JP2016021034A - Protective film, film laminate and polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-supporting protective film having a low moisture permeability in a thin layer state. A protective film according to the present invention is formed of a repeating unit having a bifunctional urethane (meth) acrylate-derived structure, and the repeating unit has a plurality of types of saturated cyclic aliphatic groups. Because even a thin layer has low moisture permeability, the polarizing film to which the protective film is attached does not easily absorb moisture even in a high temperature and high humidity environment, and expansion and contraction of the polarizing film is suppressed. Will be done. [Selection diagram] None

Description

  The present invention relates to a protective film, a film laminate, and a polarizing plate.

  In recent years, liquid crystal displays used in TVs and mobile devices are becoming thinner and thinner, and technical development is proceeding with the aim of making the components used in these displays, particularly polarizing plates, extremely thin. In general, a polarizing plate is adhered to both sides of a polarizing film made of a polyvinyl alcohol film uniaxially stretched by adsorbing iodine with an adhesive such as an optical film such as triacetyl cellulose (hereinafter referred to as TAC) as a protective film. It has a combined configuration. In order to bond the TAC film to the polarizing film, a hydrophilic adhesive is used.

  Such a conventional polarizing plate has a high moisture permeability of a TAC film as a protective film and a large expansion and contraction due to moisture absorption and dehumidification. When exposed to a long period of time, there are problems that the optical function as a polarizing plate is impaired, and physical troubles due to curling and warping of the polarizing plate occur.

  In order to improve these, the case where the acrylic film or polyester film with a low water vapor transmission rate is used is increasing. Further, as a method for adhering the protective film to the polarizing film, a method using an energy ray curable composition as an adhesive has also been adopted. However, in the method of adhering the protective film to the polarizing film, it is difficult to make the protective film thin (for example, 40 μm or less) from the viewpoint of handleability and durability during work, which is a big problem. .

  In order to solve such problems, in Patent Document 1, an uncured ionizing radiation curable resin (energy ray curable resin) is applied on a base film or a base film on which a release layer is formed. There has been proposed a method of forming a protective film on a polarizing film by bonding the polarizing film to the coated surface, curing the cured resin, and peeling the base film.

  Patent Document 2 discloses a technique for achieving thinning by forming a functional layer and an adhesive layer on a base film having a release layer formed on both sides and adhering it to a polarizing film. Furthermore, Patent Document 3 describes a method of forming a protective film for protecting a polarizing film with a film thickness of 40 μm or less by applying and curing an energy ray curable resin directly on the polarizing film.

JP 2006-163082 A JP2012-27260A JP 2014-010311 A

  However, the thinner the protective film is, the easier it is for moisture to permeate. Therefore, the moisture permeability tends to increase, and the polarizing plate bonded to the protective film is easy to absorb moisture and dehumidify. Furthermore, when a protective film that is not self-supporting, that is, cannot retain its shape with the protective film itself, expansion and contraction of the polarizing film due to moisture absorption and dehumidification cannot be suppressed. As a result, there is a problem that cracks occur in the polarizing film, or the polarizing film and the protective film are peeled off and the function of the polarizing plate is not exhibited.

  In any of the above-mentioned patent documents, there is no detailed explanation on moisture permeability and no self-supporting property in both of the above-mentioned patent documents for such problems. There is no description that an independent protective film is formed, and it cannot be said that the above problem has been solved.

  In view of the above problems, an object of the present invention is to provide a protective film having a low moisture permeability and a self-supporting property in a thin layer state.

  As a result of intensive studies on the above problems, the present inventors have focused on urethane (meth) acrylate monomers that have hardly been conventionally used as protective film materials, and urethanes having a plurality of types of saturated cyclic aliphatic groups. It has been found that the protective film obtained from the (meth) acrylate monomer has low moisture permeability in a thin layer state and is self-supporting.

（一般式（１）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す）
＜７＞上記繰り返し単位が、下記一般式（２）で表される構造であることを特徴とする＜４＞に記載の保護フィルム。

（一般式（２）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す）
＜８＞上記繰り返し単位が、下記一般式（３）で表される構造であることを特徴とする＜５＞に記載の保護フィルム。

（一般式（３）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す）
＜９＞上記繰り返し単位が、下記一般式（４）で表される構造であることを特徴とする＜４＞に記載の保護フィルム。

（一般式（４）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す）
＜１０＞上記Ｒ^１が、３−メチレン−３,５,５-トリメチルシクロヘキサン環であり、Ｒ^３がジメチレントリシクロデカン環であることを特徴とする＜４＞〜＜９＞の何れか１項に記載の保護フィルム。
＜１１＞上記ブロックＢが、下記一般式（５）で表される構造であることを特徴とする＜２＞に記載の保護フィルム。

（一般式（５）中、Ｒ^６は飽和環状脂肪族基を示し、Ｒ^７は水素原子またはメチル基を示し、ｙおよびｚは、０〜２の整数である）
＜１２＞上記Ｒ^６が、トリシクロデカン環であることを特徴とする＜１１＞に記載の保護フィルム。
＜１３＞上記チオエーテル結合を有する構造が、下記一般式（６）で表される構造であることを特徴とする＜３＞に記載の保護フィルム。

（一般式（６）中、Ｒ^８は、水素原子がメチル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、Ｘはそれぞれ独立して−Ｓ−または−Ｓ−Ｈを示し、ｎは１〜４の整数を示す）
＜１４＞上記チオエーテル結合を有する構造が、下記一般式（７）で表される構造であることを特徴とする＜３＞に記載の保護フィルム。

（一般式（７）中、Ｒ^９は、水素原子がアルキル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、Ｘはそれぞれ独立して−Ｓ−または−Ｓ−Ｈを示し、Ｒ^１０は水素原子またはメチル基を示し、ｐは１〜３の整数を示す）
＜１５＞透湿度が１５０ｇ／（ｍ^２・２４時間）以下、
かつ、引張弾性率が１５００ＭＰａ以上、または、引張強度が２５ＭＰａ以上であることを特徴とする＜１＞〜＜１４＞の何れか１項に記載の保護フィルム。
＜１６＞請求項１〜１５の何れか１項に記載の保護フィルムの少なくとも片面に、
（１）上記保護フィルムを支持するフィルム基材、
（２）耐擦傷性を有するハードコート層、
（３）光を散乱させる防眩層、および、
（４）上記保護フィルム上に備えられた高屈折率層と、上記高屈折率層に備えられた低屈折率層とで構成された反射防止層、の何れかを備えることを特徴とするフィルム積層体。
＜１７＞偏光フィルムの少なくとも片面に、＜１＞〜＜１５＞の何れか１項に記載の保護フィルムを備えることを特徴とする偏光板。 The present invention includes the following forms.
<1> It is formed by a repeating unit having a structure derived from a bifunctional urethane (meth) acrylate,
The said repeating unit has multiple types of saturated cycloaliphatic group, The protective film characterized by the above-mentioned.
<2> the repeating unit which is block A;
<1> characterized in that it is composed of a block B containing a structure derived from a bifunctional (meth) acrylate having one kind of saturated cycloaliphatic group. Protective film.
<3> including a polymer chain composed of a plurality of the above repeating units,
The protective film according to <1> or <2>, wherein a structure having a thioether bond is bonded at least in the polymer chain or at the terminal of the polymer chain.
<4> The repeating unit is
The following structure A containing a saturated cycloaliphatic group R ¹ , and
The protective film according to any one of characterized in that it comprises the following structure C that includes a saturated cyclic aliphatic group ^{R 3 <1> ~ <3} >.
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ³ —O— (Structure C)
<5> The repeating unit is
Further, the protective film according to <4>, which comprises the following structure B containing saturated aliphatic chain R ^2.
—O—R ² —CO— (Structure B)
<6> The protective film according to <5>, wherein the repeating unit has a structure represented by the following general formula (1).

(In General Formula (1), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)
<7> The protective film according to <4>, wherein the repeating unit has a structure represented by the following general formula (2).

(In the general formula (2), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)
<8> The protective film according to <5>, wherein the repeating unit has a structure represented by the following general formula (3).

(In General Formula (3), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain containing a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)
<9> The protective film according to <4>, wherein the repeating unit has a structure represented by the following general formula (4).

(In General Formula (4), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain including a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)
<10> Any ^one of <4> to <9>, wherein R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, and R ³ is a dimethylenetricyclodecane ring 2. The protective film according to item 1.
<11> The protective film according to <2>, wherein the block B has a structure represented by the following general formula (5).

(In General Formula (5), R ⁶ represents a saturated cycloaliphatic group, R ⁷ represents a hydrogen atom or a methyl group, and y and z are integers of 0 to 2)
<12> The protective film according to <11>, wherein R ⁶ is a tricyclodecane ring.
<13> The protective film according to <3>, wherein the structure having a thioether bond is a structure represented by the following general formula (6).

(In General Formula (6), R ⁸ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with a methyl group, and each X independently represents —S— or —S—H. N represents an integer of 1 to 4)
<14> The protective film according to <3>, wherein the structure having a thioether bond is a structure represented by the following general formula (7).

(In the general formula (7), R ⁹ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with an alkyl group, and each X independently represents —S— or —S—H. R ¹⁰ represents a hydrogen atom or a methyl group, and p represents an integer of 1 to 3)
<15> Moisture permeability is 150 g / (m ² · 24 hours) or less,
And the tensile elasticity modulus is 1500 Mpa or more, or tensile strength is 25 Mpa or more, The protective film of any one of <1>-<14> characterized by the above-mentioned.
<16> At least one surface of the protective film according to any one of claims 1 to 15,
(1) A film substrate that supports the protective film,
(2) a hard coat layer having scratch resistance;
(3) an antiglare layer that scatters light, and
(4) A film comprising any one of an antireflection layer composed of a high refractive index layer provided on the protective film and a low refractive index layer provided on the high refractive index layer. Laminated body.
<17> A polarizing plate comprising the protective film according to any one of <1> to <15> on at least one surface of a polarizing film.

  Since the protective film according to the present invention has a low moisture permeability even if it is a thin layer, the polarizing film to which the protective film is bonded is difficult to absorb moisture even in a high-temperature and high-humidity environment. Expansion and contraction of the film is suppressed.

  Hereinafter, although the protective film, film laminated body, and polarizing plate which concern on this invention are demonstrated, this invention is limited to the following description and is not interpreted.

"Protective film"
The protective film according to the present invention is formed by a repeating unit having a structure derived from a urethane (meth) acrylate that is a monomer, and the repeating unit has a plurality of types of saturated cycloaliphatic groups. That is, in the protective film, the matrix forming the polymer is formed of repeating units having a structure derived from urethane (meth) acrylate.

  The protective film according to the present invention is composed of at least the above repeating unit. When the basic aspect of the structure is roughly classified, (1) an aspect mainly composed of the above repeating unit, (2) the above repeating unit is a block A, A mode mainly comprising a copolymer with another block B, (3) a structure having a thioether bond in a polymer chain mainly comprising the above repeating unit, or a copolymer of the above block A and block B ( Hereinafter, there is an embodiment including a “thioether structure” as appropriate. First, the basic configuration (1) will be described, followed by (2) and (3).

  The protective film according to the present invention is formed of a repeating unit having a structure derived from a bifunctional urethane (meth) acrylate, and the repeating unit has a plurality of types of saturated cycloaliphatic groups. That is, in the protective film, the matrix forming the polymer is formed of repeating units having a structure derived from urethane (meth) acrylate.

  The structure derived from the urethane (meth) acrylate means a urethane (meth) acrylate monomer unit, that is, a structure in which a double bond of a (meth) acrylate group is cleaved in a urethane (meth) acrylate monomer. Since the double bond of the (meth) acrylate group is cleaved at both ends, it is bifunctional.

  The repeating unit has a urethane bond (—NH—CO—O—). The number of the urethane bonds is not particularly limited, and is 1 to 8, for example. The urethane bond is a polar group, and the urethane bonds in each repeating unit are close to each other by intermolecular force. On the other hand, saturated cycloaliphatic groups are nonpolar cyclic structures and have a high molecular weight. It is considered that the intermolecular force generates a high cohesive force due to the high molecular weight of the saturated cycloaliphatic group contributing to the intermolecular interaction between the urethane bonds. As a result, the protective film constituted by the above repeating units is self-supporting and also has low moisture permeability in a thin layer state.

  The urethane (meth) acrylate monomer unit has a plurality of types of saturated cyclic aliphatic groups. Although it does not specifically limit as a saturated cycloaliphatic group, From a viewpoint of raising the cohesion force resulting from molecular weight, it is preferable that it is a saturated cycloaliphatic group 5 or more membered ring. Although the upper limit of the number of member rings is not particularly limited, it is, for example, 15-membered ring or less, preferably 10-membered ring or less, from the viewpoint of easy synthesis of a monomer that is a raw material for the protective film. When the saturated cyclic aliphatic group has a plurality of cyclic structures, the number of member rings represents the maximum number of member rings of the cyclic structure, and the saturated cyclic aliphatic group has a bicyclo ring or a tricyclo ring. This means the number of ring members in the ring structure excluding the bridge carbon connecting the bridgehead carbon. For example, in the case of a tricyclodecane ring, the number of member rings is nine.

  The main chain of the cyclic structure of the saturated cycloaliphatic group may be formed only by carbon atoms, or may be formed by oxygen atoms and / or nitrogen atoms in addition to carbon atoms. Moreover, the C1-C10 linear and / or branched structure may be added to the carbon atom of the said cyclic structure.

Examples of the saturated cycloaliphatic group include a 3,5,5-trimethylcyclohexane ring, a tricyclodecane ring, an adamantane ring, and the like. The saturated cycloaliphatic group may be bonded to a urethane bonding group via a saturated aliphatic chain, and the rigidity of the repeating unit can be suitably adjusted by changing the carbon number of the saturated aliphatic chain. The saturated aliphatic chain includes a straight chain structure and a branched chain structure, and an example of the straight chain structure includes — (CH ₂ ) _n — (n is an integer of 1 to 10), From the viewpoint of reducing the flexibility and increasing the rigidity, it is particularly preferably — (CH ₂ ) — or — (CH ₂ ) ₂ —. On the other hand, examples of the branched structure include structures in which hydrogen on at least one carbon of the linear structure is substituted with a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or the like.

  When the 3,5,5-trimethylcyclohexane ring described above is bonded to two urethane bonds via a methylene chain, the 3-methylene-3,5,5-trimethylcyclohexane ring is bonded to each urethane bond. Thus, when the tricyclodecane ring is bonded to two urethane bonds via a methylene chain, the dimethylene tricyclodecane ring is bonded to each urethane bond.

  The 3-methylene-3,5,5-trimethylcyclohexane ring and the dimethylenetricyclodecane ring are preferable ring structures, and in a protective film including the ring structure in a polymer chain, low moisture permeability and self-supporting properties are preferable. Expressed.

  The main chain of the repeating unit preferably contains a saturated aliphatic chain having 5 to 10 carbon atoms in addition to the saturated cyclic aliphatic group. When the saturated aliphatic chain has 5 or more carbon atoms, flexibility is imparted to the repeating unit by the saturated aliphatic chain having a long chain length and flexibility, and the brittleness of the protective film is reduced. On the other hand, when the carbon number is 10 or less, an increase in moisture permeability in the protective film can be suppressed. The saturated aliphatic chain may have a straight chain structure or a branched chain structure. The saturated aliphatic chain constitutes a part of the repeating unit, for example, in a structure via a urethane bond or an ester bond.

Examples of the straight chain _{structure, - (CH 2) n1 -} (n1 is an integer of 5-10) include, in particular, - _{(CH 2) 5} - is preferably. On the other hand, examples of the branched structure include structures in which hydrogen on at least one carbon of the linear structure is substituted with a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or the like.

As an example of the repeating unit, a structure including the following structure A including a saturated cycloaliphatic group R ¹ and a structure including the following structure C including a saturated cycloaliphatic group R ³ can be exemplified.
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ³ —O— (Structure C)
The repeating unit, for example, diisocyanates containing R ^1, diols containing R ^3, and can be obtained from the urethane (meth) acrylate obtained by using a (meth) acrylate, it can be easily manufactured. As an example, the ratio of the structure A and the structure C can be m + 1: m or m: m + 1, and the m represents an integer of 1 to 4.

Further, the repeating units may further comprise the following structure B comprising the following saturated aliphatic chain R ^2.
—O—R ² —CO— (Structure B)
The repeating unit is, for example, an isocyanate having a (meth) acrylate or (meth) acryl group in addition to a diisocyanate containing R ¹ , an ester containing R ² (optionally used), a diol containing R ³ And can be easily manufactured. As an example, the ratio of the structure A, the structure B, and the structure C can be m + 1: m (r + s): m, m + 1: k + n: m, m: m (r + s): m + 1, m: k + n: m + 1. . M represents an integer of 1 to 4, r and s each represent an integer of 0 to 2, and the sum of r and s is 1 to 2, k represents an integer of 0 to 2, n Represents an integer of 0-2.

（一般式（１）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す） Specific examples of the repeating unit having the saturated cycloaliphatic group and saturated aliphatic chain described above are shown below. As shown in the general formula (1), the structure derived from (meth) acrylate is a (meth) acrylate structure H ₂ C═CH—CO ₂ — (or H ₂ C═C (CH ₃ ) —CO ₂ —. ) Of the carbon-carbon double bond is cleaved to form a single bond.

(In General Formula (1), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)

  When m in the said General formula (1) is an integer of 1-4, the water vapor transmission rate of a protective film can be reduced more and also a tensile elasticity modulus and tensile strength are raised more. m is more preferably 1 or 2, and even more preferably 1. The same applies to general formulas (2), (3), and (4) described later.

In the general formula (1), R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, R ² is — (CH ₂ ) ₅ —, and R ³ is a dimethylene tricyclodecane ring. A preferred structure in which R ⁴ and R ⁵ are hydrogen atoms, r and s are 1 and x is 1 is shown below.

（一般式（２）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す） Other specific examples of the repeating unit are shown below.

(In the general formula (2), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)

In the general formula (2), R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, R ² is — (CH ₂ ) ₅ —, and R ³ is a dimethylene tricyclodecane ring. Preferred repeating units in which R ⁴ and R ⁵ are hydrogen atoms, and k and n are 1 are shown below.

（一般式（３）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す） Other specific examples of the repeating unit are shown below.

(In General Formula (3), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain containing a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)

In the general formula (3), R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, R ² is — (CH ₂ ) ₅ —, and R ³ is a dimethylene tricyclodecane ring. Preferred repeating units in which R ⁴ and R ⁵ are hydrogen atoms, r and s are 1 and x is 1 are shown below.

（一般式（４）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す） Other specific examples of the repeating unit are shown below.

(In General Formula (4), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain including a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)

In the general formula (4), R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, R ² is — (CH ₂ ) ₅ —, and R ³ is a dimethylene tricyclodecane ring. Preferred repeating units in which R ⁴ and R ⁵ are hydrogen atoms, and k and n are 1 are shown below.

  The isomers having the structures represented by the general formula (1a), the general formula (2a), the general formula (3a), and the general formula (4a) are also included in the repeating unit according to the present invention.

  Next, the form regarding a copolymer among the protective films of this invention is demonstrated. The protective film according to the present embodiment is a co-polymer containing the above repeating unit which is block A and block B including a structure derived from a bifunctional (meth) acrylate having one kind of saturated cycloaliphatic group. It is constituted by a polymer. In other words, the protective film according to the copolymer includes a block A (repeating unit) including a bifunctional urethane (meth) acrylate monomer unit having a plurality of types of saturated cycloaliphatic groups, and one type of the protective film. It can be said that it comprises a copolymer containing a block B containing a bifunctional (meth) acrylate monomer unit having a saturated cycloaliphatic group.

  The repeating unit that is the block A is as described above. Block B comprises a bifunctional (meth) acrylate monomer unit having one type of saturated cycloaliphatic group. This block B contains a (meth) acrylate monomer unit and does not contain a urethane bond. The part derived from the acrylate of block A is bonded to the part derived from the acrylate of other block A or block B (-block A-block A- or -block A-block B-).

  -CO-O- of the (meth) acrylate moiety in the block B is more linear than -CO-NH-, which is a nonlinear structure of the urethane (meth) acrylate moiety, and has low flexibility. Further, since the block B has only one type of saturated cycloaliphatic group, it has a linear structure and higher rigidity than the block A. The protective film containing the copolymer containing only the block A has low moisture permeability and is self-supporting even in a thin layer state, but the self-supporting property is further enhanced by using the block B having high rigidity in combination. The protective film which can suppress the expansion-contraction of the polarizing film resulting from moisture absorption and dehumidification can be provided.

  The bifunctional (meth) acrylate monomer unit according to block B has one kind of saturated cycloaliphatic group. The saturated cycloaliphatic group is not particularly limited, but is preferably a 5-membered or higher saturated cycloaliphatic group from the viewpoint of obtaining a moisture permeability lowering effect due to molecular weight. The upper limit of the number of member rings is not particularly limited, but is, for example, 15-membered ring or less, preferably 10-membered ring or less, from the viewpoint of easy synthesis of the monomer that is the raw material of block B. When the saturated cyclic aliphatic group has a plurality of cyclic structures, the number of member rings represents the maximum number of member rings of the cyclic structure, and the saturated cyclic aliphatic group has a bicyclo ring or a tricyclo ring. This means the number of ring members in the ring structure excluding the bridge carbon connecting the bridgehead carbon. For example, in the case of a tricyclodecane ring, the number of member rings is nine.

  The main chain of the cyclic structure of the saturated cycloaliphatic group may be formed only by carbon atoms, or may be formed by oxygen atoms and / or nitrogen atoms in addition to carbon atoms. Moreover, the C1-C10 linear and / or branched structure may be added to the carbon atom of the said cyclic structure.

Examples of the saturated cycloaliphatic group include a tricyclodecane ring, a 3,5,5-trimethylcyclohexane ring, an adamantane ring, and the like. The saturated cycloaliphatic group may be bonded to the structure derived from (meth) acrylate via a saturated aliphatic chain, and the rigidity of the repeating unit is suitably improved by changing the carbon number of the saturated aliphatic chain. Can be adjusted. The saturated aliphatic chain includes a straight chain structure and a branched chain structure. As an example of the straight chain structure, — (CH ₂ ) _n — (n is an integer of 1 to 10) can be mentioned, and a copolymer From the viewpoint of lowering the flexibility of the resin and increasing the rigidity, it is particularly preferably — (CH ₂ ) — or — (CH ₂ ) ₂ —. Moreover, also when the block B is a structure which does not have a linear structure, rigidity is increased (the above n is 0). On the other hand, examples of the branched structure include structures in which hydrogen on at least one carbon of the linear structure is substituted with a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or the like.

  When the 3,5,5-trimethylcyclohexane ring described above is bonded to two (meth) acrylate-derived structures via a methylene chain, each 3-methylene-3,5,5-trimethylcyclohexane ring is ( When the tricyclodecane ring is bonded to two (meth) acrylate-derived structures via a methylene chain, each dimethylenetricyclodecane ring is bonded to each ( It is combined with a structure derived from (meth) acrylate.

  The dimethylene tricyclodecane ring is a preferable ring structure, and low moisture permeability and self-supporting property are suitably expressed in a protective film including the ring structure in a polymer chain.

（一般式（５）中、Ｒ^６は飽和環状脂肪族基を示し、Ｒ^７は水素原子またはメチル基を示し、ｙおよびｚは、０〜２の整数である） Specific examples of the block B having the saturated cycloaliphatic group and the saturated aliphatic chain described above are shown below. The block B has a structure derived from (meth) acrylate at both ends, and the structure derived from (meth) acrylate is bonded to another block B or to the block A (-block B-block B-, Or -Block B-Block A-). As shown in the general formula (5), the acrylate-derived site is a structure in which the carbon-carbon double bond of the acrylate structure H ₂ C═HC—CO ₂ — is cleaved to form a single bond (methacrylate The structure is the same).

(In General Formula (5), R ⁶ represents a saturated cycloaliphatic group, R ⁷ represents a hydrogen atom or a methyl group, and y and z are integers of 0 to 2)

In the general formula (5), R ⁶ is a tricyclodecane ring, R ⁷ is a hydrogen atom,
A preferred structure in which y and z are 1 is shown below.

  The weight ratio of the block A to the block B in the copolymer is not particularly limited, but in order to make the degree of tensile elastic modulus of the protective film due to the block B suitable, the block A: block B = 70: 30. ~ 15: 85 is preferable, 60:40 to 15:85 is more preferable, and 50:50 to 15:85 is particularly preferable.

  Further, the proportion of the copolymer in the protective film according to the present invention is preferably high from the viewpoint of reducing the moisture permeability of the protective film and increasing the self-supporting property, and is 70% by mass or more based on the total mass of the protective film, It is preferably 99.5% by mass or less, more preferably 80% by mass or more and 99.5% by mass or less.

  Next, the thioether structure will be described. The thioether structure has a thioether bond and has at least a —S—R structure (R is a hydrocarbon). The single bond on the opposite side of R of the thioether structure is bonded to the structure derived from the (meth) acrylate of the repeating unit, and a hydrogen bond is generated between the —S— of the thioether bond and the urethane bond in the repeating unit. The self-supporting property of the protective film can be enhanced.

  The thioether structure may have at least one or more thioether bonds (-S-). However, the inclusion of a plurality of thioether bonds is preferable because strong hydrogen bonds are generated and the protective film is more self-supporting. .

The hydrocarbon R having a thioether structure has a cyclic structure and / or a chain structure. The main chain of the cyclic structure and the chain structure may be formed of only carbon atoms, or may be formed of oxygen atoms and / or nitrogen atoms in addition to carbon atoms. Examples of the cyclic structure include a 1,2,3-triazine ring, a 1,2,4-triazine ring, a 1,3,5-triazine ring, a maleimide ring, and the like. As the chain structure, — (CH ₂ ) _n2 - (n2 alkyl chain is exemplified represented by is an integer of 1 to 10). A hydrogen atom bonded to a carbon atom and / or a nitrogen atom constituting the main chain of the cyclic structure and the chain structure may be substituted with a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or the like.

  The thioether structure may have a substituent, and examples thereof include a carbonyl group, a carboxyl group, an amino group, an amide group, and a hydroxyl group.

The thioether structure is bonded to (1) a polymer chain constituted by a plurality of repeating units, or (2) to an end of the polymer chain. In the case of (1), the thioether structure has a plurality of thioether bonds, one thioether bond is bonded to the structure derived from the (meth) acrylate of the repeating unit, and the other thioether bond is bonded to the other repeating unit. Bonded to (meth) acrylate-derived structure. The bonding state of (1) when the repeating unit has a site derived from acrylate is shown below. In addition, when a thioether structure has 3 or 4 or more -S-, it couple | bonds with a some repeating unit.

上記Ｒは炭化水素を示す。 On the other hand, in the case of (2), a thioether structure is bonded to the end of the polymer chain, and the thioether structure is bonded to one repeating unit. The bonding state of (2) when the repeating unit has a site derived from acrylate is shown below.

R represents a hydrocarbon.

  Although the bonding state between the repeating unit and the thioether structure has been described above, when the polymer chain is formed of the repeating unit (block A) and the block B, (1 ′) the thioether structure includes the block A and the block B. May be combined with each other, may be combined with block A and another block A, or may be combined with block B and another block B. The (2 ′) thioether structure is bonded to the block A and may not be bonded to the other block A or the block B, or is bonded to the block B, and the block A or the other block B is bonded. It does not have to be joined.

（一般式（６）中、Ｒ^８は、水素原子がメチル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、Ｘはそれぞれ独立して−Ｓ−または−Ｓ−Ｈを示し、ｎは１〜４の整数を示す） A thioether structure having one or more thioether bonds has been described above. Specific examples of such a thioether structure having both a cyclic structure and a chain structure are shown below.

(In General Formula (6), R ⁸ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with a methyl group, and each X independently represents —S— or —S—H. N represents an integer of 1 to 4)

In the general formula (6), specific examples of R ⁸ include — (CH ₂ ) — and — (CH ₂ ) ₂ —, and the hydrogen atom of the alkyl chain includes a methyl group, an ethyl group, and a propyl group. It may be substituted by a substituent such as

X is —S— or —S—H, and the structure in which two X are —S— is represented by the following general formula (6a), and one X is —S— and the other X is — The structure which is S—H is represented by the following general formula (6b), and the structure in which two X are —S—H is represented by the following general formula (6c). -S- of the thioether structure is bonded to a structure derived from (meth) acrylate as a repeating unit.

（一般式（７）中、Ｒ^９は、水素原子がアルキル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、Ｘはそれぞれ独立して−Ｓ−または−Ｓ−Ｈを示し、Ｒ^１０は水素原子またはメチル基を示し、ｐは１〜３の整数を示す） Furthermore, specific examples of the thioether structure having a chain structure are shown below.

(In the general formula (7), R ⁹ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with an alkyl group, and each X independently represents —S— or —S—H. R ¹⁰ represents a hydrogen atom or a methyl group, and p represents an integer of 1 to 3)

In the general formula (7), specific examples of R ⁹ include — (CH ₂ ) — and — (CH ₂ ) ₂ — alkyl chains, and the hydrogen atom of the alkyl chain is a methyl group or an ethyl group. , May be substituted with a substituent such as a propyl group.

In the general formula (7), among the structures in which p is 3, the structure in which three Xs are -S- is represented by the following general formula (7a), the two Xs are -S-, The structure in which one X is —S—H is represented by the following general formula (7b), and the structure in which one X is —S— and the other two X are —S—H is A structure represented by the formula (7c) and three Xs being —S—H is represented by the following general formula (7d). -S- of the thioether structure is bonded to a structure derived from (meth) acrylate as a repeating unit.

  In particular, the thioether structure represented by the general formula (7d) is tetrafunctional and forms a complicated three-dimensional structure with a repeating unit, so that the resulting protective film has high tensile strength and can be more self-supporting. .

  The weight ratio of the repeating unit to the thioether structure in the protective film is not particularly limited, but the repeating unit: thioether structure = 95: 5 to 5 in order to make the tensile strength value of the protective film due to the thioether structure suitable. It is preferably 50:50, more preferably 95: 5 to 80:20, and particularly preferably 90:10 to 70:30.

  When the protective film is composed of a copolymer, the weight ratio between the total amount of repeating units (block A) and block B and the thioether structure is the total amount of repeating units (block A) and block B: thioether structure. = 95: 5 to 50:50 is preferable, 95: 5 to 80:20 is more preferable, and 90:10 to 70:30 is particularly preferable.

  Moreover, the ratio of the polymer chain in the protective film according to the present invention (repeating unit (block A), block B and the total ratio of the thioether structure) is high from the viewpoint of reducing the moisture permeability of the protective film and increasing the self-supporting property. Desirably, it is preferably 70% by mass or more and 99.5% by mass or less, and more preferably 80% by mass or more and 99.5% by mass or less with respect to the total mass of the protective film.

  The structure of the protective film according to the present invention is formed by the polymer chain (repeating unit (block A), block B and thioether structure). The protective film is formed by pyrolysis GC-MS and FT-IR. Judgment can be made by analysis. In particular, pyrolysis GC-MS is useful because it can detect a monomer unit contained in a protective film as a monomer component.

  The protective film may contain various additives such as an ultraviolet absorber, a leveling agent, and an antistatic agent as long as the film formability, tensile elastic modulus, tensile strength, and low moisture permeability of the protective film are not impaired. Thereby, it is possible to give an ultraviolet absorption characteristic, a peeling characteristic, and an antistatic characteristic to a protective film.

  As the ultraviolet absorber, known ones can be used. For example, benzophenone series such as 2-hydroxy-4-octoxybenzophenone and 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2- (2′-hydroxy) Examples include benzotriazoles such as -5-methylphenyl) benzotriazole, hindered amines such as phenyl salsylate, and pt-butylphenyl salsylate. Known leveling agents and antistatic agents can also be used.

  Since the protective film according to the present invention is formed into a thin film, for example, the upper limit value of the film thickness is 50 μm, and more preferably 30 μm. Although a lower limit is not specifically limited, From a viewpoint of ensuring low moisture permeability reliably, it is preferable that it is 5 micrometers, and it is more preferable that it is 10 micrometers.

The moisture permeability of the protective film according to the present invention is a low value, and is preferably 150 g / (m ² · 24 o'clock) or less, more preferably 120 g / (m ² · 24) in a thin layer of 30 μm. Hour) or less, and particularly preferably 100 g / (m ² · 24 hours) or less. Although the lower limit of moisture permeability is not particularly limited, it is, for example, 15 g / (m ² · 24 o'clock) or more.

  The protective film according to the present invention is self-supporting. Having self-supporting means that the protective film can maintain its shape by itself, and as one criterion, if the tensile elastic modulus of the protective film is 1500 MPa or more, the protective film is self-supporting. In order to suppress expansion and contraction of the polarizing film due to moisture absorption and dehumidification, the tensile elastic modulus is preferably high, specifically 1500 MPa or more, more preferably 2500 MPa or more. Although an upper limit is not specifically limited, For example, it is 4500 MPa.

  As another criterion, if the tensile strength of the protective film is 15 MPa or more, the protective film is self-supporting. In order to suppress expansion and contraction of the polarizing film due to moisture absorption and dehumidification, the tensile strength is preferably high, and more preferably 25 MPa or more. Although an upper limit is not specifically limited, For example, it is 100 MPa.

<Film laminate>
Next, a film laminated body is demonstrated. The film laminate according to the present invention is provided on at least one side of the protective film.
(1) A film substrate that supports the protective film,
(2) a hard coat layer having scratch resistance;
(3) an antiglare layer that scatters light, and
(4) One of an antireflection layer including a high refractive index layer provided on the protective film and a low refractive index layer provided on the high refractive index layer is provided. Of course, the said film laminated body may be equipped with arbitrary said (1)-(4) on both surfaces of a protective film. That is, the same type of layers on both sides (for example, (1) on the surface of the protective film, (1) on the back side) or different layers (for example, (1) on the front side of the protective film, (2) on the back side, or the surface (2) and (3)) may be provided on the back surface. Furthermore, (1) to (4) are provided with other layers (1) to (4), and may have a laminated structure. Hereinafter, (1) to (4) will be described.

[Film base]
The protective film which concerns on this invention can be handled integrally in the state laminated | stacked with the other film. In addition, when manufacturing a film laminate by forming a protective film on a film substrate by a coating method such as a roll coating method or a gravure coating method, the film substrate should be used as part of the film laminate. You can also.

  The film base material plays a role of supporting the protective film, and finally has a release layer on the side where the protective film is laminated in order to peel and remove. In addition, when a film base material is equipped with a functional layer via a release layer, after the film base material is bonded to the functional layer side of the protective film and then removed by removing the film base material, the functional layer is usually Is not transferred to the film substrate side but transferred to the protective film side.

  Usually, since a protective film and a polarizing film are bonded together with an ultraviolet curable adhesive, it is preferable that the film base material does not have ultraviolet absorbing ability so as not to prevent ultraviolet irradiation. Furthermore, the optical properties may be inspected in various manufacturing processes in which other films are provided on the polarizing plate and processed up to the display device, and this influences the measurement of the optical properties of the polarizing film and protective film, which is the basic configuration of the polarizing plate It is preferable that the film substrate has transparency so as to minimize the thickness. From such a viewpoint, a polyester film substrate having a release layer is preferably used as the film substrate.

  As described above, the polyester film substrate may have a release layer, and other functional layers may be formed in addition to the release layer. Examples of the functional layer include a hard coat layer (HC layer), an antiglare layer (AG layer), and an antireflection layer (LR layer). These layers are formed on the release layer of the polyester film, laminated on the protective film, and then peeled off the polyester substrate from the release layer, whereby each functional layer and the protective film are laminated. The body is easily obtained.

[Hard coat layer]
The hard coat layer has a hard coat property. The hard coat property in the present invention is based on JIS K5600: 1999, and the scratch hardness according to the pencil method under a load of 500 g and a speed of 1 mm / s is 2H or more.

  As the resin component constituting the hard coat layer, an ionizing radiation curable resin is suitable because it can be cured efficiently with a simple processing operation, and after curing, a coating having sufficient strength and transparency is provided. An ionizing radiation curable resin can be used without any particular limitation.

  Examples of the ionizing radiation curable resin include monomers and oligomers having radical polymerizable functional groups such as acryloyl group, methacryloyl group, acryloyloxy group, and methacryloyloxy group, and cationic polymerizable functional groups such as epoxy group, vinyl ether group, and oxetane group. , Prepolymers, and compositions obtained by mixing polymers alone or as appropriate are used. Examples of monomers include methyl acrylate, methyl methacrylate, methoxy polyethylene methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, ethylene glycol dimethacrylate, dipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and the like. it can. As oligomers and prepolymers, polyester acrylate, polyurethane acrylate, polyfunctional urethane acrylate, epoxy acrylate, polyether acrylate, acrylate compounds such as alkit acrylate, melamine acrylate, silicone acrylate, unsaturated polyester, tetramethylene glycol diglycidyl ether, Epoxy compounds such as propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether and various alicyclic epoxies, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[((3- Oxeta such as ethyl-3-oxetanyl) methoxy] methyl} benzene, di [1-ethyl (3-oxetanyl)] methyl ether Mention may be made of the compound. Examples of the polymer include polyacrylate, polyurethane acrylate, and polyester acrylate. These can be used alone or in combination. Among these ionizing radiation curable resins, in particular, a polyfunctional monomer having 3 or more functional groups can increase the curing speed and improve the hardness of the cured product. Furthermore, by using polyfunctional urethane acrylate, the hardness and flexibility of the cured product can be imparted.

  The ionizing radiation curable resin can be cured by irradiation with ionizing radiation as it is, but in the case of curing by ultraviolet irradiation, it is necessary to add a photopolymerization initiator. Photopolymerization initiators include radical polymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin, and benzoin methyl ether, and cationic polymerization starts such as aromatic cyazonium salts, aromatic sulfonium salts, aromatic iodonium salts, and metallocene compounds. The agents can be used alone or in appropriate combination.

  The thickness of the hard coat layer is not particularly limited as long as the hard coat property is exhibited, but is generally 2 μm or more and 10 μm or less.

  In order to provide functions other than hard coat properties, various additives can be added to the hard coat layer. Examples include fluorine or silicone leveling agents added to improve releasability when peeling from polyester film substrates, and electrons added to prevent dust adhesion due to peeling charge during peeling. A conjugated, metal oxide or ionic antistatic agent may be appropriately selected and used according to the required function. The point which can use an additive agent is the same also about the following glare-proof layer and a low refractive index layer.

(Anti-glare layer)
The antiglare layer has an antiglare function that scatters light, and realizes the antiglare function by external haze and / or internal haze. It contains translucent fine particles, or both.

  There is no particular limitation on the method of forming the unevenness on the surface of the antiglare layer, but the method of applying an ionizing radiation curable resin on the polyester film substrate on which the unevenness is formed, and curing after application is It is preferable because the shape can be easily controlled.

  The shape of the surface irregularities on the polyester substrate side of the antiglare layer is determined by the required antiglare property. A more preferable uneven shape can be defined by the roughness parameter Ra, and Ra: 0.01 μm or more, Sm: 50 μm to 500 μm, and average inclination angle: 0.1 ° to 3.0 °. More preferred.

  The thickness of the antiglare layer is not particularly limited, but if it is too thin, the uneven shape formed on the support side remains on the uneven surface formed on the support side, which is not preferable in terms of preventing glare. On the other hand, when it is too thick, curling and cracking due to curing shrinkage of the resin occur, which is not preferable in terms of handling, and therefore it is preferably in the range of 1 to 12 μm.

  On the other hand, the translucent fine particles added to the ionizing radiation curable resin to cause internal haze include, for example, acrylic resin, polystyrene resin, styrene-acrylic copolymer, nylon resin, silicone resin, melamine resin, polyether. Organic resin fine particles such as sulfone resin and inorganic fine particles such as silica can be used. Here, the translucent fine particles preferably have a refractive index difference of 0.04 or less from the resin component, and more preferably 0.01 or less. A large difference in refractive index from the resin component is not preferable because internal scattering occurs in the antiglare layer and the contrast is lowered.

  The film thickness of the antiglare layer is not particularly limited as long as the antiglare property is exhibited, but is generally 2 μm or more and 10 μm or less. In addition to the antiglare property, the antiglare layer can also have a hard coat property. In this case, the hard coat property is imparted by adjusting the resin component used.

(Antireflection layer)
The antireflection layer is composed of a low refractive index layer and a high refractive index layer. The low refractive index layer is a layer having a lower refractive index than the adjacent high refractive index layer (hard coat layer, antiglare layer or protective film), and has a low refractive index in a state of being laminated with the high refractive index layer. This contributes to preventing reflection of light from the layer side. Here, the high refractive index and the low refractive index do not define an absolute refractive index, but rather specify that the refractive indices of the two layers are relatively high or low compared. The reflectance is said to be lowest when both have the relationship of the following formula 1.

n2 = (n1) ^1/2 (Formula 1)
(N1 is the refractive index of the high refractive index layer, n2 is the refractive index of the low refractive index layer)

In order to suitably exhibit the antireflection function, the refractive index of the low refractive index layer is preferably 1.45 or less. Examples of the material having these characteristics include LiF (refractive index n = 1.4), MgF ₂ (n = 1.4), 3NaF · AlF ₃ (n = 1.4), AlF ₃ (n = 1. 4) Inorganic low-reflective material in which inorganic material such as Na ₃ AlF ₆ (n = 1.33) is finely divided and contained in acrylic resin or epoxy resin, fluorine-based, silicone-based organic compound, heat Examples thereof include organic low reflection materials such as plastic resins, thermosetting resins, and radiation curable resins. Among them, in particular, the fluorine-based fluorine-containing material is excellent in antifouling property, and therefore, it is preferable in terms of preventing contamination when the low refractive index layer becomes the surface.

  Examples of the fluorine-containing material include vinylidene fluoride copolymers, fluoroolefin / hydrocarbon copolymers, fluorine-containing epoxy resins, fluorine-containing epoxy acrylates, fluorine-containing silicones, which are easily dissolved in organic solvents. , Fluorine-containing alkoxysilane, fluorine-containing polysiloxane, and the like. These can be used alone or in combination. The fluorine-containing polysiloxane is obtained by curing a hydrolyzable silane compound and / or a mixture containing at least a hydrolyzate thereof and a curing accelerator, as a hydrolyzable silane compound, as a film forming agent and an antistatic agent. A cation-modified silane compound having the above function can also be contained.

  The film thickness of the low refractive index layer is not particularly limited as long as the antireflection function is exhibited in relation to the high refractive index layer, but is generally 0.05 μm or more and 0.2 μm or less. In general, the thickness is preferably 0.05 μm or more and 10 μm or less. The low refractive index layer exhibits an antireflection function in relation to the high refractive index layer, but can also have a hard coat property by selecting a raw material. Further, the high refractive index layer may have a hard coat property or may have an antiglare property depending on the selection of raw materials.

"Polarizer"
Next, a polarizing plate provided with the protective film of the present invention will be described. The polarizing plate according to the present invention is provided with the protective film on at least one surface of the polarizing film.

  The polarizing film is made of a polyvinyl alcohol resin (PVA resin), and has a property of transmitting light having a vibration surface in a certain direction out of light incident on the polarizing film and absorbing light having a vibration surface orthogonal to the direction. A dichroic dye is typically adsorbed and oriented on a PVA resin. The PVA resin constituting the polarizing film can be obtained by saponifying a polyvinyl acetate resin. The polyvinyl acetate resin used as the raw material for the PVA resin may be a copolymer of polyvinyl acetate, which is a homopolymer of vinyl acetate, or a copolymer of vinyl acetate and other monomers copolymerizable therewith. Good. A polarizing film can be produced by subjecting the film made of the PVA resin to uniaxial stretching, dyeing with a dichroic dye, and boric acid crosslinking treatment after dyeing. As the dichroic dye, iodine or a dichroic organic dye is used. Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or after dyeing with a dichroic dye, for example, during a boric acid crosslinking treatment. May be. Thus, the polarizing film which consists of PVA resin which is manufactured and the dichroic dye adsorbs and becomes one of the constituent materials of a polarizing plate.

  An ultraviolet curable adhesive is preferably used for pasting the polarizing film and the protective film. As long as the ultraviolet curable adhesive is supplied in a liquid coatable state, a known one that has been conventionally used in the production of polarizing plates can be used, but from the viewpoint of weather resistance, polymerizability, etc. A polymerizable compound, for example, one containing an epoxy compound as one of the ultraviolet curable components is preferable.

  In addition to cationically polymerizable compounds such as epoxy compounds as representative examples of ultraviolet curable adhesives, polymerization initiators, particularly to generate cationic species or Lewis acids upon irradiation with ultraviolet rays, initiate polymerization of cationically polymerizable compounds. The photocationic polymerization initiator is blended. Further, a thermal cationic polymerization initiator that initiates polymerization by heating, and various other additives such as a photosensitizer may be blended.

  The polarizing plate which concerns on this invention is equipped with the said protective film on at least one surface, and the structure provided with a protective film on both surfaces of a polarizing plate is contained. Since the protective film has a low moisture permeability even if it is a thin layer, the polarizing film is difficult to absorb moisture even in a high temperature and high humidity environment, and the expansion and contraction of the polarizing film is suppressed.

<< Method for producing protective film and film laminate >>
[Protective film forming step]
Although the manufacturing method of the protective film which concerns on this invention will not be specifically limited if the said protective film can be manufactured, The method including the protective film formation process containing the following processes (A1) and (A2) as an example is mentioned.
Step (A1): The energy beam curable composition is applied on the film substrate or the release layer of the film substrate.
Step (A2): After coating, the energy beam curable composition is cured to form a protective film.

  The energy beam curable composition contains urethane (meth) acrylate as an essential component. The said urethane (meth) acrylate which is a monomer is a raw material of a protective film, The repeating unit described in the said << protective film >> is formed when the said monomer polymerizes.

  In another embodiment, the energy ray curable composition includes a urethane (meth) acrylate that generates the repeating unit (block A) and a (meth) acrylate that generates the block B as a raw material for the protective film. These monomers are copolymerized to form the copolymer described in the above << Protective film >>.

  Furthermore, in another embodiment, the energy ray curable composition is a (meth) acrylate that produces block B in addition to urethane (meth) acrylate that produces (block A) that produces the repeating unit, and / or Includes thiols that produce thioether structures. When urethane (meth) acrylates are polymerized, or urethane (meth) acrylate and (meth) acrylate are copolymerized to form a polymer chain, thiol binds in the polymer chain or at the end of the polymer chain Thus, a protective film containing the polymer chain described in the above << Protective film >> is formed.

  The urethane (meth) acrylate is different from the above repeating unit in that the structure derived from (meth) acrylate at both ends is a (meth) acrylate group, but the monomer is a plurality of types or one type of saturated cyclic aliphatic group. The structure other than both ends, such as having a point, is common, and the same applies to (meth) acrylates. Specific examples of the saturated cycloaliphatic group, saturated aliphatic chain and the like are the same as the description of the repeating unit (block A) and block B, and thus the description thereof is omitted.

Examples of the urethane (meth) acrylate include the following structure A having a saturated cycloaliphatic group R ¹ , structure B (optionally included) having the following saturated aliphatic chain R ² , and a saturated cycloaliphatic group R. ^The structure containing the following structure C which has ³ can be illustrated. The structure b is an optional component.
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ² —CO— (Structure B)
—O—R ³ —O— (Structure C)

The urethane (meth) acrylate includes, for example, a diisocyanate containing R ¹ , an ester containing R ² (optionally used), a diol containing R ³ , a (meth) acrylate, or a (meth) acrylic group. It can be obtained by using an isocyanate having, and can be easily produced.

  As an example, the ratio of the structure A, the structure B, and the structure C is m + 1: m (r + s): m, m + 1: k + n: m, m: m (r + s): m + 1, or m: k + n: m + 1. Can do. M represents an integer of 1 to 4, r and s each represent an integer of 0 to 2, and the sum of r and s is 1 to 2, k represents an integer of 0 to 2, n Represents an integer of 0-2.

  The method for synthesizing the urethane (meth) acrylate is not particularly limited. As an example, first, a bifunctional intermediate is synthesized, and an isocyanate having a (meth) acrylate or (meth) acryl group is attached to both ends of the intermediate. A method of synthesizing is mentioned.

（一般式（８）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す） Specifically, when a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (1) described above is exemplified, [1] an ester having R ² and a diol having R ³ are represented by m ( r + s): m is reacted at a molar ratio of m, and further m + 1 mole of diisocyanate having R ¹ is reacted to obtain an intermediate having —N═C═O groups at both ends. [2] Thereafter, urethane (meth) acrylate represented by the following general formula (8) is obtained by reacting 1 mol of the intermediate with 2 mol of (meth) acrylate.

(In General Formula (8), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain containing a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)

（一般式（９）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す） An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (2) is as follows: [1] A diisocyanate having R ¹ and a diol having R ³ are reacted at a molar ratio of m + 1: m. To obtain an intermediate having —N═C═O groups at both ends. [2-1] Then, 2 mol of (meth) acrylate is reacted with 1 mol of the above intermediate, or [2-2] k + n mol of R ² with respect to 1 mol of the above intermediate. Obtained by reacting 2 moles of (meth) acrylate, or [2-3] reacting 2 moles of (meth) acrylate with an ester having k + n moles of R ^2. The urethane (meth) acrylate corresponding to the repeating unit represented by the general formula (9) can be obtained by any method in which (meth) acrylate is reacted with 1 mol of the above intermediate.

(In the general formula (9), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)

（一般式（１０）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｒおよびｓはそれぞれ０〜２の整数を示し、かつ、ｒとｓとの和は１〜２であり、ｘは０〜３の整数を示す） An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (3) is as follows: [1] A diisocyanate having R ¹ and an ester having R ² are converted into m: m (r + s) moles. The reaction is carried out in a ratio, and further m + 1 mol of diol having R ³ is reacted to obtain an intermediate having hydroxyl groups at both ends. [2] Thereafter, urethane (meth) acrylate corresponding to the repeating unit represented by the general formula (10) is obtained by reacting 2 mol of an isocyanate having a (meth) acryl group with 1 mol of an intermediate. Is obtained.

(In General Formula (10), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3)

（一般式（１１）中、Ｒ^１は飽和環状脂肪族基を示し、Ｒ^２は炭素数５〜１０の直鎖または分鎖構造を含む飽和脂肪族鎖を示し、Ｒ^３は、Ｒ^１と異なる飽和環状脂肪族基を示し、Ｒ^４は水素原子またはメチル基を示し、Ｒ^５は、水素原子、メチル基またはエチル基を示し、ｍは１〜４の整数を示し、ｋは０〜２の整数を示し、ｎは０〜２の整数を示し、ｘは０〜３の整数を示す） An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (4) is as follows: [1] A diisocyanate having R ¹ and a diol having R ³ are reacted at a molar ratio of m: m + 1. Thus, an intermediate having hydroxyl groups at both ends is obtained. [2-1] Then, 2 mol of an isocyanate having a (meth) acryl group is reacted with 1 mol of the intermediate, or [2-2] k + n mol with respect to 1 mol of the intermediate. After reacting the ester having R ² , react with an isocyanate having 2 mol of a (meth) acryl group, or [2-3] k + n mol with respect to an isocyanate having 2 mol of a (meth) acryl group. The urethane (meth) acryl acrylate obtained by reacting the ester having R ² is reacted with 1 mol of the above intermediate, and the repeating unit represented by the general formula (11) is obtained by any method. The corresponding urethane (meth) acrylate is obtained.

(In General Formula (11), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3)

（一般式（１２）中、Ｒ^６は飽和環状脂肪族基を示し、Ｒ^７は水素原子またはメチル基を示し、ｙおよびｚは、０〜２の整数である） The structure of a typical monomer that gives rise to block B is shown below.

(In General Formula (12), R ⁶ represents a saturated cycloaliphatic group, R ⁷ represents a hydrogen atom or a methyl group, and y and z are integers of 0 to 2)

  The thiol (R-SH) used in the present invention is the above-described thioether structure (R-S-) and hydrocarbon except that H on S becomes a single bond during the reaction with urethane (meth) acrylate. Since it is common in the point of R and the specific example of hydrocarbon R was already demonstrated with the thioether structure mentioned above, description regarding hydrocarbon R is not repeated.

（一般式（１３）中、Ｒ^８は、水素原子がメチル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、ｎは１〜４の整数を示す） Representative thiols that give rise to thioether structures are shown below.

(In the general formula (13), R ⁸ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with a methyl group, and n represents an integer of 1 to 4)

（一般式（１４）中、Ｒ^９は、水素原子がアルキル基によって置換されていてもよい炭素数１または２のアルキル鎖を示し、Ｒ^１０は水素原子またはメチル基を示し、ｑは１〜４の整数を示す） Other structures of typical thiols that give rise to thioether structures are shown below.

(In the general formula (14), R ⁹ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with an alkyl group, R ¹⁰ represents a hydrogen atom or a methyl group, and q represents 1 to 2) Indicates an integer of 4)

In the general formula (14), R ⁹ is an ethyl chain, a methyl group is bonded to the β carbon of the ethyl chain, and a suitable thiol in which q is 4 is shown below. This thiol is tetrafunctional and gives rise to a thioether structure that forms a complex three-dimensional structure with the repeating unit.

  The energy ray curable composition is prepared by adding a photopolymerization initiator for initiating polymerization of a monomer to a monomer for generating a repeating unit. In another embodiment, the energy ray curable composition is prepared by adding a photoinitiator to the monomer that generates the repeating unit (block A), the monomer that generates the block B, and / or the thiol. Do it.

  Photopolymerization initiators include radical polymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin, and benzoin methyl ether, and cationic polymerization starts such as aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, and metallocene compounds. The agents can be used alone or in appropriate combination.

  You may add various additives, such as the ultraviolet absorber mentioned above by << protective film >>, a leveling agent, and an antistatic agent, to an energy-beam curable composition.

  In the energy ray-curable composition, each ratio of the monomer (the total amount of the monomer that generates the repeating unit (block A) and the monomer that generates the block B), the thiol, the photopolymerization initiator, and any of various additives is the material. However, as an example, the total of the monomer and the thiol is 50% by mass or more and 99% by mass or less, and the photopolymerization initiator is 0.5% by mass or more and 10% by mass. % Or less, and various additives may be 0.01 mass% or more and 50 mass% or less. Moreover, you may add organic solvents, such as toluene, to an energy-beam curable composition.

  The weight ratio of the monomer A that generates the block A and the monomer B that generates the block B is set so that the degree of improvement in the tensile elastic modulus of the protective film due to the block B is suitable. The range is preferably from 70:30 to 15:85, more preferably from 60:40 to 15:85, and particularly preferably from 50:40 to 15:85.

  Regarding the thiol, the weight ratio of the monomer (monomer A or a mixture of the monomer A and the monomer B) to the thiol that generates the thioether structure is suitable for the degree of improvement in the tensile strength of the protective film due to the thioether structure. In order to achieve this, it is preferable that monomer: thiol = 95: 5 to 50:50, and more preferably 90:10 to 70:30.

  In order to apply the prepared energy ray curable composition on the film substrate or the release layer of the film substrate, considering continuous productivity, a coating method such as a roll coating method or a gravure coating method is used. It is preferable to use it. By the coating method, the energy ray-curable composition can be applied so as to form a thin layer, for example, a protective film of 50 μm or less, preferably 30 μm or less.

  Curing in the step (A2) can be performed by irradiating ultraviolet rays from an ultraviolet irradiation device. The ultraviolet light source to be used is not particularly limited, but has a light emission distribution at a wavelength of 400 nm or less, such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, etc. Can be used. In the case of using an adhesive having an epoxy compound as an active energy ray-curable component, a high-pressure mercury lamp or a metal halide lamp having a lot of light of 400 nm or less is preferably used as an ultraviolet light source in consideration of an absorption wavelength exhibited by a general polymerization initiator. It is done.

  By curing the energy ray-curable composition, a protective film is formed on the film substrate or the release layer of the film substrate, and a film laminate in which the protective film is laminated on the film substrate is obtained. . Furthermore, a single protective film can be obtained by peeling the protective film from the film laminate.

[Functional layer formation process]
As a variation of the manufacturing method of a film laminated body, the manufacturing method which contains a functional layer formation process (B) before a protective film formation process (A1) and (A2) is mentioned. In the functional layer forming step (B), the energy ray curable composition that is the raw material of the functional layer is applied to the film base material or the release layer of the film base material and cured to function on the film base material. Form a layer.

  Although it does not specifically limit as said functional layer, The hard-coat layer, glare-proof layer, and antireflection layer which were mentioned above are mentioned. The energy ray curable composition that is a raw material of the functional layer includes the resin described above in the description of the hard coat layer, the antiglare layer, and the antireflection layer. An organic solvent such as methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone (MIBK), isopropyl alcohol (IPA), or toluene may be added.

  In order to apply the energy ray curable composition, which is the raw material of the functional layer, on the film substrate or the release layer of the film substrate, considering continuous productivity, roll coating method, gravure coating method, etc. It is preferable to use this coating method. According to the energy ray curable composition to be used, a method of arbitrarily heating and then crosslinking and curing by ultraviolet irradiation or the like may be used.

  When a functional layer is formed on the film substrate in the functional layer forming step, an energy ray curable composition containing urethane (meth) acrylate is applied to the functional layer side of the film substrate in the protective film forming step (A1). . When the functional layer is a plurality of layers, it is usually applied to the last formed functional layer side.

  When the film base material in which unevenness | corrugation was formed is used, an unevenness | corrugation is formed in the functional layer formed in the said film base material, and it functions as an anti-glare layer which has anti-glare property. The shape of the unevenness is determined by the required antiglare property, and a more preferable uneven shape can be defined by the roughness parameter Ra, Ra: 0.01 μm or more, Sm: 50 μm to 500 μm, average slope Angle: More preferably from 0.1 ° to 3.0 °.

  When forming the functional layer, a plurality of layers can be formed. For example, when forming a plurality of hard coat layers, the first hard coat layer is formed on the film substrate or the release layer of the film substrate, and the second hard coat layer is formed on the first hard coat layer. Form. Thereafter, in the step (A1), an energy ray curable composition containing urethane (meth) acrylate is applied to the second hard coat layer side. An antiglare layer may be formed in place of the second hard coat layer.

  Moreover, when forming an antireflection layer, a low refractive index layer is formed on a film base material or a release layer of the film base material, and a high refractive index layer is formed on the low refractive index layer. Furthermore, the energy ray-curable composition containing urethane (meth) acrylate is applied to the high refractive index layer side in the step (A1). Thereby, the film laminated body laminated | stacked in order of the film base material, the functional layer, and the protective film is obtained.

<< Polarizing plate manufacturing method >>
The polarizing plate according to the present invention includes the protective film according to the present invention on at least one surface of the polarizing film. In the method for producing a polarizing plate according to the present invention, it is important that the protective film is bonded to a polarizing film, and the bonding method may be a known method, and is not particularly limited.

  As the protective film, the protective film may be used alone, but it is preferable to use the protective film together with the film laminate, that is, the film base material, for ease of handling.

  For example, after a protective film forming step or after obtaining a laminate including a protective film after a functional layer forming step and a protective film forming step, the polarizing film is bonded to the protective film side of the film laminate. A polarizing plate according to the present invention is obtained.

  The process which concerns on the manufacturing method of a polarizing plate is demonstrated more concretely. The following steps (C1) to (C4) are performed after the protective film forming step or after the functional layer forming step and the protective film forming step.

(C1) a coating step of applying an ultraviolet curable adhesive to the protective film side (or polarizing film) of the film laminate,
(C2) A laminating step in which a polarizing film (or a protective film side of the film laminate) is applied to the UV curable adhesive surface applied in the coating step and pressed.
(C3) A curing step of curing the ultraviolet curable adhesive by irradiating ultraviolet rays from an ultraviolet irradiation device to the film laminate in which the protective film is bonded to the polarizing film via the ultraviolet curable adhesive,
(C4) The peeling process which peels and removes a film base material (support base material) from a laminated | multilayer film as needed.

  In the coating step (C1), an ultraviolet curable adhesive is applied to the protective film side of the film laminate, which becomes the bonding surface of the polarizing film (or instead of the protective film side of the film laminate, the polarizing film is applied to the polarizing film). Apply UV curable adhesive). As a coating machine used here, a well-known thing can be used suitably, for example, the coating machine using a gravure roll etc. are mentioned.

  In the bonding step (C2), after passing through the coating step (C1), the polarizing film is laminated on the adhesive-coated surface of the film laminate, and the bonding is performed while pressing (polarization in the coating step (C1)). When an ultraviolet curable adhesive is applied to the film, the film is laminated while pressing the protective film side of the film laminate on the surface of the ultraviolet curable adhesive). A known means can be used for pressurization in the bonding step, but from the viewpoint that pressurization while continuous conveyance is possible, a method of sandwiching between a pair of nip rolls is preferably used. Is preferably about 150 to 500 N / cm as a linear pressure when sandwiched between a pair of nip rolls.

  In a hardening process (C3), after bonding a film laminated body to a polarizing film, an ultraviolet-ray is irradiated from an ultraviolet irradiation device, and an ultraviolet curable adhesive is hardened. Ultraviolet rays are irradiated through the film laminate. The ultraviolet light source to be used is not particularly limited, but has a light emission distribution at a wavelength of 400 nm or less, such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, etc. Can be used. When using an adhesive having an epoxy compound as an energy ray curable component, a high-pressure mercury lamp or metal halide lamp having a large amount of light of 400 nm or less is preferably used as an ultraviolet light source in consideration of the absorption wavelength exhibited by a general polymerization initiator. .

  The peeling step (C4) is a step that is appropriately performed as necessary. The film base material laminated on the protective film by this step is peeled off and removed (if the film base material has a plurality of layers, the film base A part of the material is peeled and removed), whereby a polarizing plate is obtained. When the polarizing plate is further processed, when the surface of the protective film is desired to be protected in the post-processing step, the film substrate may be peeled after the completion of the processing.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited to the content of an Example. The protective film obtained by peeling the polyester film substrate from the obtained film laminate (when the functional layer is formed on the film substrate, the protective film and the functional layer) are measured, and the moisture permeability and tensile strength of the protective film are as follows: The measurement method was used.

[Film thickness]
The film thickness of the protective film (or protective film + functional layer) was measured using a digital linear gauge D-10HS and a digital counter C-7HS (manufactured by Ozaki Manufacturing Co., Ltd.).

[Moisture permeability]
According to the moisture permeability test method (cup method) of JIS Z0208, the number of grams of water vapor that passes through the protective film in 24 hours per 1 m ² area of the test piece in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH. It was measured.

〔Autonomy〕
The sample film was cut so that the protective film was cut to a size of 15 mm x 160 mm, using “Tensilon RTF-24” (manufactured by Yamato Kagaku) with the long side as the tensile direction, so that the gap between the grips was 100 mm. The tensile modulus and / or tensile strength were determined from the maximum slope of the stress-strain curve at a measurement load range of 40 N and a measurement speed of 20 mm / min at normal temperature (25 ° C.).

  In the evaluation of the self-supporting property, when the tensile modulus of the sample film is 1500 MPa or more and less than 2500 MPa, it is judged as ◯, when the tensile modulus is 2500 MPa or more, it is judged as ◎, and when it is ○ or ◎, it is self-supporting. Judged to be one. On the other hand, when the film formed at the stage of peeling from the PET film collapsed, it was determined as x because measurement was impossible.

  On the other hand, in the case of tensile strength, when the tensile strength of the sample film is 15 MPa or more and less than 25 MPa, it is judged as ◯, when the tensile strength is 25 MPa or more, it is judged as ◎, and when it is ○ or ◎, It was judged that there was. On the other hand, when the film formed at the stage of peeling from the PET film collapsed, it was determined as x because measurement was impossible.

[Production Example 1]
Synthesis of Compound 1:
196.29 g (1 mol) of tricyclodecane dimethanol and 228.29 g (2 mol) of ε-caprolactone were charged into a flask, the temperature was raised to 120 ° C., and 50 ppm of monobutyltin oxide was added as a catalyst. Thereafter, the reaction was carried out under a nitrogen stream until the remaining ε-caprolactone was 1% or less by gas chromatography to obtain diol (1).

  Charge 445.58 g (2 mol) of isophorone diisocyanate to another flask, add 425.57 g (1 mol) of diol (1) at a reaction temperature of 70 ° C., and when the remaining isocyanate group becomes 5.7%, 2-hydroxyethyl Add 232.24 g (2 mol) of acrylate and 0.35 g of dibutyltin laurate and react until the remaining isocyanate group is 0.1% to obtain urethane acrylate (compound 1) which is a monomer that generates repeating units (block A). (In the repeating unit of Compound 1, m is 1 in the general formula (1a)).

[Production Example 2]
Synthesis of compound 2:
114.14 g (1 mol) of ε-caprolactone and 116.12 g (1 mol) of 2-hydroxyethyl acrylate were reacted at 120 ° C. under a nitrogen stream, and with respect to 100 parts by mass of 114.14 g (1 mol) of ε-caprolactone, As a catalyst, 5 parts by mass of Kureha Co., Ltd. spherical activated carbon BAC was added, and in order to suppress radical polymerization of 2-hydroxyethyl acrylate, 4-methoxyphenol was added at 500 mg / kg to the entire polymerization system. Thereafter, the reaction was performed until ε-caprolactone became 1% or less by gas chromatography to obtain ε-caprolactone-modified hydroxyethyl acrylate (2).

  Charge 44.58 g (2 mol) of isophorone diisocyanate to the flask, add 196.29 g (1 mol) of tricyclodecane dimethanol at a reaction temperature of 70 ° C., and ε-caprolactone-modified hydroxyethyl when the residual isocyanate group becomes 5.7%. Acrylate (2) 2 mol 460.52 g was added, and the reaction was carried out until the residual isocyanate group reached 0.1% to obtain urethane acrylate (compound 2), which is a monomer that generates repeating units. M is 1 in the formula (2a)).

[Production Example 3]
Compound 1a, which is a monomer that produces repeating units, is obtained in the same manner as in Production Example 1 except that the amount of diol (1) synthesized is changed to twice and the amount of isophorone diisocyanate used is changed from 2 mol to 3 mol. (In the repeating unit of compound 1a, m is 2 in the general formula (1a)).

[Production Example 4]
Compound 1b was obtained in the same manner as in Production Example 1 except that the synthesis amount of diol (1) was changed to 3 times and the amount of isophorone diisocyanate used was changed from 2 mol to 4 mol (the repeating unit of compound 1b was In general formula (1a), m is 3.

[Example 1: Polyester film substrate / protective film]
Using the applicator, the following energy beam curable composition for forming a protective film (1) was applied to the release layer side of non-silicone release PET SG-1 (38 μm thickness) manufactured by Panac. The energy ray curable composition (P1) contains toluene and has a solid content (NV) of 60%.

The coating thickness of the energy ray curable composition (P1) was adjusted so that the film thickness after drying was 20 μm to 30 μm. The coating film is dried in a clean oven set at a drying oven temperature of 100 ° C, and then UV cured under conditions of peak illuminance of 326 mW / cm ² and integrated light intensity of 192 mJ / cm ^{2 in} a nitrogen atmosphere. A film laminate having a protective film formed on one side was obtained. The evaluation results for this film laminate are shown in Table 7.

[Example 2: Polyester film substrate / HC layer / protective film]
The following energy beam curable composition for HC layer formation (HC1) was applied to the release layer side of Panac's non-silicone release PET SG-1 (38 μm thickness) by reverse coating. The formed coating film is dried at 100 ° C for 1 minute, and then irradiated with ultraviolet light using a 120W / cm condensing high-pressure mercury lamp in a nitrogen atmosphere (irradiation distance 10cm, irradiation time 30 seconds). The film was cured to form a hard coat layer (HC layer) having a thickness of 2.5 μm and a refractive index of 1.52.

  Subsequently, the energy ray curable composition (P1) described in Example 1 was coated and dried on the HC layer side under the same conditions as in Example 1, and a film laminate in which a protective film was formed on the HC layer side. Got. The evaluation results for this film laminate are shown in Table 7.

[Example 3: Polyester film substrate / AG layer (containing filler) / protective film]
Using a bar coating method, apply a release layer coating solution on one side of a PET film (product name: Emblet S-50, manufactured by Unitika) as a support for the release film so that the dry film thickness is 2 μm. The coating film was dried at 140 ° C. for 1 minute and then cured. Thus, a support having a 2 μm-thick release layer having surface irregularities on the PET film was obtained. Subsequently, the following energy layer curable composition for AG layer formation (AG1) was applied on the release layer.

  The coating thickness was adjusted by a bar coating method so that the dry film thickness was 6 μm. The coating film of AG1 was dried at 100 ° C. for 1 minute, and then irradiated with ultraviolet rays (lamp: high pressure mercury lamp, lamp output: 120 W / cm, integrated light amount: 120 mJ / cm) to cure the coating film. Subsequently, the energy ray curable composition (P1) described in Example 1 was coated and dried on the AG layer side under the same conditions as in Example 1, and a film laminate in which a protective film was formed on the AG layer side. Got the body. The evaluation results for this film laminate are shown in Table 7.

[Example 4: Polyester film substrate / HC layer (fillerless AG) / protective film]
Using a bar coating method, apply a release layer coating solution on one side of a PET film (product name: Emblet S-50, manufactured by Unitika) as a support for the release film so that the dry film thickness is 2 μm. The coating film was dried at 140 ° C. for 1 minute and then cured. Thus, a support having a 2 μm-thick release layer having surface irregularities on the PET film was obtained. Subsequently, in the same manner as in the application of AG1 in Example 3, the following energy beam curable composition for HC layer formation (HC2) was applied on the release layer and then cured.

  Subsequently, the energy ray curable composition (P1) described in Example 1 was applied and dried on the HC layer side under the same conditions as in Example 1, and a film laminate in which a protective film was formed on the HC layer side. Got the body. The evaluation results for this film laminate are shown in Table 7.

[Example 5: Polyester film substrate / low refractive index layer / high refractive index layer / AG layer / protective film]
Using a bar coating method, apply a release layer coating solution on one side of a PET film (product name: Emblet S-50, manufactured by Unitika) as a support for the release film so that the dry film thickness is 2 μm. The coating film was dried at 140 ° C. for 1 minute and then cured. Thus, a support having a 2 μm-thick release layer having surface irregularities on the PET film was obtained.

  The following low-refractive-index paint (LR1) is applied on the release layer by the reverse coating method, and the coating film is dried at 100 ° C. for 1 minute. The thickness is 0.1 μm and the low refractive index is 1.38. A refractive index layer was formed. Then, it left still at 60 degreeC for 120 hours for hardening of a low refractive index layer.

  Subsequently, the energy ray curable composition for AG layer formation (AG1) described in Example 3 was applied onto the low refractive index layer by a bar coating method so that the dry film thickness was 6 μm, and the coating was performed at 100 ° C. After drying for 1 minute, UV irradiation was performed (lamp: high-pressure mercury lamp, lamp output: 120 W / cm, integrated light amount: 120 mJ / cm), the coating film was cured, and an AG layer was formed.

  Subsequently, the energy ray curable composition (P1) described in Example 1 was coated and dried on the AG layer side under the same conditions as in Example 1, and a film laminate in which a protective film was formed on the AG layer side. Got the body. The evaluation results for this film laminate are shown in Table 7.

[Example 6: Polyester film substrate / low refractive index layer / high refractive index layer / HC layer / protective film]
Using an applicator, the low refractive index paint (LR1) described in Example 5 was applied to the release layer side of a non-silicone release PET SG-1 (38 μm thickness) manufactured by Panac Co., Ltd. And dried for 1 minute, followed by curing to form a low refractive index layer having a thickness of 0.1 μm and a refractive index of 1.38. Then, it left still at 60 degreeC for 120 hours for hardening of a low refractive index layer.

  Subsequently, the following energy beam curable composition for HC layer formation (HC3) was applied on the low refractive index layer by a reverse coating method. After drying at 100 ° C for 1 minute, ultraviolet irradiation (irradiation distance 10 cm, irradiation time 30 seconds) with one 120 W / cm condensing type high-pressure mercury lamp in a nitrogen atmosphere to cure the coating film, thickness 2.5 μm, An HC layer having a refractive index of 1.64 was formed.

  Subsequently, the energy ray curable composition (P1) described in Example 1 was applied and dried on the HC layer side under the same conditions as in Example 1, and a film laminate in which a protective film was formed on the HC layer side. Got the body. The evaluation results for this film laminate are shown in Table 7.

[Examples 7 to 9: polyester film substrate / protective film]
In Example 7, Compound 1 was changed to Compound 2, in Example 8, Compound 1 was changed to Compound 1a, and in Example 9, Compound 1 was changed to Compound 1b. A film laminate in which a protective film was formed on one side of the PET film was obtained. The evaluation results for this film laminate are shown in Table 7.

[Comparative Example 1]
A cured film is formed on one side of the PET film in the same manner as in Example 1 except that Compound 1 is changed to Compound 3 (manufactured by Shin-Nakamura Chemical Co., Ltd.) represented by the following general formula (12a). Got. The evaluation results for this film laminate are shown in Table 7.

  As shown in Table 7, when Compound 1 of Examples 1 to 6 and Compound 2 of Example 7 were used, protective films with very low moisture permeability were obtained. In Examples 2 to 6, the moisture permeability is lower due to the functional layer. A high value was also obtained for the tensile modulus, and a very useful protective film could be obtained. Although the protective film which uses the compound 1a, 1b in Examples 8 and 9 as a raw material is inferior to Example 1 (Compound 1), it has achieved low moisture permeability. Moreover, evaluation of a tensile elasticity modulus is (circle) and sufficient self-supporting property is obtained as the protective film which concerns on this invention.

  On the other hand, the cured film formed in Comparative Example 1 is very hard and fragile, and breaks when peeled off from the PET film. Therefore, the film thickness, moisture permeability, and tensile strength cannot be measured, and the self-supporting property is completely absent. There wasn't. Since the monomer having only one type of saturated cycloaliphatic group was used when synthesizing compound 3, the repeating unit of compound 3 contains only one type of saturated cycloaliphatic group. For this reason, it is thought that the cohesive force between repeating units became excessively high and the cured film with high brittleness was formed.

[Example 10: Polyester film substrate / protective film]
Using an applicator, the following energy film curable composition for forming a protective film (P2) was applied to the release layer side of non-silicone release PET SG-1 (38 μm thickness) manufactured by Panac. The energy ray curable composition (P2) contains toluene and has a solid content (NV) of 60%.

The coating thickness of the energy beam curable composition (P2) was adjusted such that the coating thickness after drying was 20 μm to 30 μm. The coating film is dried in a clean oven set at a drying oven temperature of 100 ° C, and then UV cured under conditions of peak illuminance of 326 mW / cm ² and integrated light intensity of 192 mJ / cm ^{2 in} a nitrogen atmosphere. A film laminate having a protective film formed on one side was obtained. The evaluation results for this film laminate are shown in Table 9.

[Example 11: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 was changed to 66.5 parts by mass of Compound 1 and 28.5 parts by mass of Compound 3. The film laminated body in which was formed was obtained. Compound 3 is a monomer that generates block B and is represented by the following general formula (12a). Table 9 shows the evaluation results for the film laminate.

[Example 12: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 was changed to 47.5 parts by mass of Compound 1 and 47.5 parts by mass of Compound 3. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 9.

[Example 13: Polyester film substrate / HC layer / protective film]
In the same manner as in Example 2, an HC layer was formed on a PET film (PET SG-1). Subsequently, the energy ray curable composition used in Example 12 was applied and dried on the HC layer side under the same conditions as in Example 12 to obtain a film laminate in which a protective film was formed on the HC layer side. . The evaluation results for this film laminate are shown in Table 9.

[Example 14: Polyester film substrate / AG layer (containing filler) / protective film]
In the same manner as in Example 3, a coating film of AG1 was cured on a PET film (product name: Emblet S-50 manufactured by Unitika). Subsequently, the energy ray curable composition used in Example 12 was applied and dried on the AG layer side under the same conditions as in Example 12 to obtain a film laminate in which a protective film was formed on the AG layer side. . The evaluation results for this film laminate are shown in Table 9.

[Example 15: Polyester film substrate / HC layer (fillerless AG) / protective film]
In the same manner as in Example 4, an HC layer was formed on a PET film (product name: Emblet S-50 manufactured by Unitika). Subsequently, the energy ray curable composition used in Example 12 was applied and dried on the HC layer side under the same conditions as in Example 12 to obtain a film laminate in which a protective film was formed on the HC layer side. . The evaluation results for this film laminate are shown in Table 9.

[Example 16: Polyester film substrate / low refractive index layer / high refractive index layer / AG layer / protective film]
In the same manner as in Example 5, a low refractive index layer was formed on the PET film, and an AG layer was further formed on the low refractive index layer. Subsequently, the energy ray curable composition used in Example 12 was applied and dried on the AG layer side under the same conditions as in Example 12 to obtain a film laminate in which a protective film was formed on the AG layer side. It was. The evaluation results for this film laminate are shown in Table 9.

[Example 17: polyester film substrate / low refractive index layer / high refractive index layer / HC layer / protective film]
In the same manner as in Example 6, a low refractive index layer was formed on the PET film, and an HC layer was formed on the low refractive index layer. Subsequently, the energy ray curable composition used in Example 12 was applied and dried on the HC layer side under the same conditions as in Example 12 to obtain a film laminate in which a protective film was formed on the HC layer side. It was. The evaluation results for this film laminate are shown in Table 9.

[Example 18: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 was changed to 28.5 parts by mass of Compound 1 and 66.5 parts by mass of Compound 3. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 9.

[Example 19: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 was changed to 19 parts by mass of Compound 1 and 76 parts by mass of Compound 3. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 9.

[Comparative Example 2]
A film laminate in which a protective film is formed on one side of a PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 is changed to 95 parts by mass of Compound 3. (Compound 1 was not used). The evaluation results for this film laminate are shown in Table 9.

Example 20
A cured film was formed on one side of the PET film in the same manner as in Example 10 except that Compound 1 was changed to Compound 2, and a film laminate was obtained. The evaluation results for this film laminate are shown in Table 9.

Example 21
Cured on one side of a PET film in the same manner as in Example 20, except that the monomer (95 parts by mass of Compound 2) used in Example 20 was changed to 57 parts by mass of Compound 2 and 38 parts by mass of Compound 3. A film was formed to obtain a film laminate. The evaluation results for this film laminate are shown in Table 9.

[Example 22]
A cured film is formed on one side of a PET film in the same manner as in Example 10 except that the monomer (95 parts by mass of Compound 1) used in Example 10 is changed to 95 parts by mass of Compound 1a. Got. The evaluation results for this film laminate are shown in Table 9.

Example 23
A cured film was formed on one side of the PET film in the same manner as in Example 10, except that the monomer (95 parts by mass of compound 1a) used in Example 22 was changed to 38 parts by mass of compound 1a and 57 parts by mass of compound 3. And a film laminate was obtained. The evaluation results for this film laminate are shown in Table 9.

As shown in Table 9, in Example 10, only Compound 1 was used as a monomer and Compound 3 was not used. As a result, the protective film obtained had a film thickness of 24 μm and a moisture permeability of 77 g / ( m ² · 24 h). Next, in Example 11, when Compound 3 was used as the monomer B, the moisture permeability of the obtained protective film was 60 g / (m ² · 24 h), and a low moisture permeability film was obtained. I understand.

  Next, in Example 12, when the ratio of the compound 3 was increased, the tendency for moisture permeability to decrease was confirmed. In Examples 13-17, when the functional layer was provided in the protective film, it turns out that low moisture permeability is maintained. In Example 18 and Example 19, when the ratio of the compound 3 was further increased, the tendency for the moisture permeability to decrease could be confirmed. Moreover, it has also been demonstrated that the protective films obtained in Examples 11 to 19 have a high tensile elastic modulus and have sufficient self-supporting properties.

  On the other hand, when only Compound 3 was used without using Compound 1 as a monomer in Comparative Example 2, the obtained cured film was very hard and fragile, and collapsed when peeled from the PET film. The moisture permeability and tensile strength could not be measured, and there was no self-supporting property. When synthesizing compound 3, a monomer having only one type of saturated cycloaliphatic group is used, and compound 3 contains only one type of saturated cycloaliphatic group. For this reason, it is considered that the cohesive force between the monomer units was excessively high, and a cured film having high brittleness was formed.

  In Example 20, Compound 2 was used as a monomer, and in Example 21, in addition to Compound 2, Compound 3 was used. From a comparison of both examples, Example 11 confirmed the effect of reducing moisture permeability. From a comparison between Example 22 and Example 23 using Compound 3 as a monomer, the effect of reducing moisture permeability could be confirmed in Example 23.

[Example 24: Polyester film substrate / protective film]
Using the applicator, the protective film-forming energy beam curable composition (P2) used in Example 10 was applied to the release layer side of non-silicone release PET SG-1 (38 μm thickness) manufactured by Panac. The energy ray curable composition (P2) contains toluene and has a solid content (NV) of 60%.

The coating thickness of the energy beam curable composition (P2) was adjusted such that the coating thickness after drying was 20 μm to 30 μm. The coating film is dried in a clean oven set at a drying oven temperature of 100 ° C, and then UV cured under conditions of peak illuminance of 326 mW / cm ² and integrated light intensity of 192 mJ / cm ^{2 in} a nitrogen atmosphere. A film laminate having a protective film formed on one side was obtained. The evaluation results for this film laminate are shown in Table 10.

[Example 25: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 90.25 parts by mass of Compound 1 and 4.75 parts by mass of Compound 4. The film laminated body in which was formed was obtained. Compound 4 (manufactured by Showa Denko KK) is a thiol, and its structure is represented by the following general formula (14a). Table 10 shows the evaluation results for the film laminate.

[Example 26: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 85.5 parts by mass of Compound 1 and 9.5 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

[Example 27: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 76 parts by mass of Compound 1 and 19 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

[Example 28: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24, except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 66.5 parts by mass of Compound 1 and 28.5 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

[Example 29: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 57 parts by mass of Compound 1 and 38 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

[Example 30: Polyester film substrate / HC layer / protective film]
In the same manner as in Example 2, an HC layer was formed on a PET film (PET SG-1). Subsequently, the energy ray curable composition used in Example 26 was applied and dried on the HC layer side under the same conditions as in Example 26 to obtain a film laminate in which a protective film was formed on the HC layer side. . The evaluation results for this film laminate are shown in Table 10.

[Example 31: Polyester film base material / AG layer (containing filler) / protective film]
In the same manner as in Example 3, a coating film of AG1 was cured on a PET film (product name: Emblet S-50 manufactured by Unitika). Subsequently, the energy ray curable composition used in Example 26 was applied and dried on the AG layer side under the same conditions as in Example 26 to obtain a film laminate in which a protective film was formed on the AG layer side. . The evaluation results for this film laminate are shown in Table 10.

[Example 32: Polyester film substrate / HC layer (fillerless AG) / protective film]
In the same manner as in Example 4, an HC layer was formed on a PET film (product name: Emblet S-50 manufactured by Unitika). Subsequently, the energy ray curable composition used in Example 26 was applied and dried on the HC layer side under the same conditions as in Example 26 to obtain a film laminate in which a protective film was formed on the HC layer side. . The evaluation results for this film laminate are shown in Table 10.

[Example 33: Polyester film substrate / low refractive index layer / high refractive index layer / AG layer / protective film]
In the same manner as in Example 5, a low refractive index layer was formed on the PET film, and an AG layer was further formed on the low refractive index layer. Subsequently, the energy ray-curable composition used in Example 26 was applied and dried on the AG layer side under the same conditions as in Example 26 to obtain a film laminate in which a protective film was formed on the AG layer side. It was. The evaluation results for this film laminate are shown in Table 10.

[Example 34: Polyester film substrate / low refractive index layer / high refractive index layer / HC layer / protective film]
In the same manner as in Example 6, a low refractive index layer was formed on the PET film, and an HC layer was formed on the low refractive index layer. Subsequently, the energy ray curable composition used in Example 26 was applied and dried on the HC layer side under the same conditions as in Example 26 to obtain a film laminate in which a protective film was formed on the HC layer side. It was. The evaluation results for this film laminate are shown in Table 10.

Example 35
A film laminate in which a protective film is formed on one side of a PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 is changed to 95 parts by mass of Compound 2. (Compound 1 was not used). The evaluation results for this film laminate are shown in Table 10.

[Example 36: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 85.5 parts by mass of Compound 2 and 9.5 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

Example 37
A film laminate in which a protective film is formed on one side of a PET film in the same manner as in Example 25 except that the monomer (95 parts by mass of Compound 1) used in Example 24 is changed to 95 parts by mass of Compound 1a. (Compound 1 was not used). The evaluation results for this film laminate are shown in Table 10.

[Example 38: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 76 parts by mass of Compound 1a and 19 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

Example 39
A film laminate in which a protective film was formed on one side of a PET film in the same manner as in Example 24 except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 95 parts by mass of Compound 1b. (Compound 1 was not used). The evaluation results for this film laminate are shown in Table 10.

[Example 40: Polyester film substrate / protective film]
A protective film on one side of the PET film in the same manner as in Example 24, except that the monomer (95 parts by mass of Compound 1) used in Example 24 was changed to 90.25 parts by mass of Compound 1b and 4.75 parts by mass of Compound 4. The film laminated body in which was formed was obtained. The evaluation results for this film laminate are shown in Table 10.

As shown in Table 10, in Example 24, when only Compound 1 was used as the monomer and Compound 4 was not used, the protective film obtained had a film thickness of 24 μm and a moisture permeability of 77 g / (m ² -24h) and the tensile strength was 20MPa. Next, in Example 25, when Compound 1 as a thiol was used in combination with Compound 1, the resulting protective film had a film thickness of 25 μm, a moisture permeability of 86 g / (m ² · 24 h), and a tensile strength of 30 MPa. When both results are compared, in Example 25, although the water vapor transmission rate is slightly increased, the tensile strength is 1.5 times, and it can be seen that a significant increase in tensile strength is achieved.

  Next, in Example 26, when the proportion of Compound 4 was increased, it was confirmed that although the water vapor transmission rate was slightly increased as compared with Example 25, the tensile strength was further increased. In Examples 27 and 28, when the proportion of Compound 4 was increased to 20% and 30%, respectively, the tensile strength further increased from the result of Example 26. In Example 29, when the ratio of Compound 4 was further increased to 40%, the tensile strength was a very high value of three times or more that in Example 24, but the moisture permeability was extremely increased.

  In Examples 30 to 34, a functional layer is provided on the protective film, but it can be seen that, similarly to Example 26, a protective film excellent in tensile strength was obtained.

In Example 35 and subsequent examples, Compound 1 was changed to another monomer having a plurality of types of saturated cycloaliphatic groups. In Example 35, when Compound 1 was changed to Compound 2 and Compound 4 as a thiol was not used in combination, the resulting protective film had a film thickness of 23 μm and a moisture permeability of 93 g / (m ² · 24 h). there were. On the other hand, in Example 36, when 10% of the thiol compound 4 was used in combination with Compound 2, the tensile strength was about twice that of Example 35, and a tendency to increase the tensile strength of the protective film could be confirmed. .

  Similarly, when Example 37 and Example 38 were performed for Compound 1a, and Example 39 and Example 40 were performed for Compound 1b, the tensile strength of the protective film was increased by using thiol compound 4 in combination with Compound 1a and 1b. The tendency to increase was confirmed.

  As is apparent from the evaluation results described in Table 10, in the production of a protective film, a protective film formed by polymerizing urethane (meth) acrylate having a plurality of types of saturated cycloaliphatic groups in combination with a thiol compound. Is understood to have low moisture permeability and high self-supporting properties.

  The protective film according to the present invention has low moisture permeability in a thin layer state and is self-supporting. Therefore, the protective film is useful as a constituent member of a polarizing plate, particularly in applications where low moisture permeability is required. Available.

Claims (17)

It is formed by a repeating unit having a structure derived from bifunctional urethane (meth) acrylate,
The said repeating unit has multiple types of saturated cycloaliphatic group, The protective film characterized by the above-mentioned. The above repeating unit being block A;
The block B which comprises the structure derived from the bifunctional (meth) acrylate which has one type of saturated cycloaliphatic group, and is comprised by the copolymer containing the structure of Claim 1 characterized by the above-mentioned. Protective film. Including a polymer chain composed of a plurality of the above repeating units,
The protective film according to claim 1 or 2, wherein a structure having a thioether bond is bound at least in the polymer chain or at the terminal of the polymer chain. The above repeating unit is
The following structure A containing a saturated cycloaliphatic group R ¹ , and
The protective film according to claim 1, comprising the following structure C containing a saturated cycloaliphatic group R ³ .
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ³ —O— (Structure C) The above repeating unit is
The protective film according to claim 4, further comprising the following structure B containing a saturated aliphatic chain R ² .
—O—R ² —CO— (Structure B) The protective film according to claim 5, wherein the repeating unit has a structure represented by the following general formula (1).

(In General Formula (1), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3) The protective film according to claim 4, wherein the repeating unit has a structure represented by the following general formula (2).

(In the general formula (2), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3) The protective film according to claim 5, wherein the repeating unit has a structure represented by the following general formula (3).

(In General Formula (3), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain containing a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and r and s each represent The integer of 0-2 is shown, and the sum of r and s is 1-2, x shows the integer of 0-3) The said repeating unit is a structure represented by following General formula (4), The protective film of Claim 4 characterized by the above-mentioned.

(In General Formula (4), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain including a straight chain or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer of 0 to 2, and x represents an integer of 0 to 3) The R ¹ is a 3-methylene-3,5,5-trimethylcyclohexane ring, and the R ³ is a dimethylenetricyclodecane ring, according to any one of claims 4 to 9, Protective film. The said block B is a structure represented by following General formula (5), The protective film of Claim 2 characterized by the above-mentioned.

(In General Formula (5), R ⁶ represents a saturated cycloaliphatic group, R ⁷ represents a hydrogen atom or a methyl group, and y and z are integers of 0 to 2) The protective film according to claim 11, wherein R ⁶ is a tricyclodecane ring. 4. The protective film according to claim 3, wherein the structure having a thioether bond is a structure represented by the following general formula (6).

(In General Formula (6), R ⁸ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with a methyl group, and each X independently represents —S— or —S—H. N represents an integer of 1 to 4) The protective film according to claim 3, wherein the structure having a thioether bond is a structure represented by the following general formula (7).

(In the general formula (7), R ⁹ represents an alkyl chain having 1 or 2 carbon atoms in which a hydrogen atom may be substituted with an alkyl group, and each X independently represents —S— or —S—H. R ¹⁰ represents a hydrogen atom or a methyl group, and p represents an integer of 1 to 3) Moisture permeability is 150 g / (m ² · 24 hours) or less,
And the tensile elasticity modulus is 1500 Mpa or more, or tensile strength is 25 Mpa or more, The protective film of any one of Claims 1-14 characterized by the above-mentioned. At least one surface of the protective film according to any one of claims 1 to 15,
(1) A film substrate that supports the protective film,
(2) a hard coat layer having scratch resistance;
(3) an antiglare layer that scatters light, and
(4) A film comprising any one of an antireflection layer composed of a high refractive index layer provided on the protective film and a low refractive index layer provided on the high refractive index layer. Laminated body.   A polarizing plate comprising the protective film according to claim 1 on at least one surface of a polarizing film.