JP6678274B1 - Laminated film roll, laminated body with hard coat film, and polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film wound body, a laminated body with a hard coat film, and a polarizing plate capable of suppressing the generation of stripes on the surface of a laminated body with a hard coat film such as a polarizing plate provided with a hard coat film. To do. A laminated film winding body is obtained by winding a laminated film in a roll shape. The laminated film has a hard coat film having a base material layer and a hard coat layer, and a protective film. The thickness of the hard coat film is 30 μm or less, and the tensile elastic modulus at a temperature of 23 ° C. and a relative humidity of 55% in the winding direction of the hard coat film is 3000 MPa or less. The hard coat film peeled off from the laminated film has a standard deviation of the film thickness distribution in the winding axis direction of 0.25 μm or less and a pencil hardness of 5 B or more and less than H. [Selection diagram] None

Description

  The present invention relates to a rolled laminate film, a laminate with a hard coat film, and a polarizing plate.

  2. Description of the Related Art Various types of optical films are used in display devices such as a liquid crystal display device and an organic electroluminescence (EL) display device. One of such optical films is a polarizing plate. The polarizing plate is provided with a protective layer for protecting the polarizing layer on one side or both sides of the polarizing layer. A protective layer used for a polarizing plate may be provided with a hard coat layer in order to improve the surface hardness (for example, Patent Documents 1 to 4).

JP 2005-103878 A JP 2009-292871 A JP 2013-136774 A JP 2017-82240 A

  A protective layer provided with a hard coat layer (hereinafter, sometimes referred to as a “film with an HC layer”) is provided with a hard coat layer (hereinafter, referred to as a “layer with an HC layer”) at the time of production or distribution on the market (before being bonded to a polarizing layer). In order to prevent the HC layer from being damaged, the film with the HC layer may be a laminated film in which the HC layer side is covered with a protective film. In addition, the film with the HC layer may be used by being bonded to the surface of the polarizing layer to obtain a polarizing plate, but the bonding of the polarizing layer and the film with the HC layer is performed using a long object. Usually, it is performed continuously. Therefore, the above-mentioned laminated film is also obtained as a long product, and this long laminated film is made into a rolled laminated film wound into a roll shape, and is distributed on the market and stored.

  And at the time of lamination of the polarizing layer and the film with the HC layer, after peeling off the protective film from the laminated film obtained by unwinding the laminated film wound body, laminating the film with the HC layer to the polarizing layer, A polarizing plate having a film with an HC layer is obtained. The present inventors have found that streaks may be visually recognized on the surface of the polarizing plate thus obtained on the side of the film with the HC layer.

  The present invention provides a laminated film wound body, a laminated body with a hard coat film, and a polarizing plate, which can suppress generation of streaks on the surface of a laminated body with a hard coat film such as a polarizing plate provided with a hard coat film. For the purpose of providing.

The present invention provides a laminated film wound body and a polarizing plate described below.
[1] A laminated film wound body in which the laminated film is wound into a roll,
The laminated film has a hard coat film having a base layer and a hard coat layer, and a protective film,
The thickness of the hard coat film is 30 μm or less,
The tensile elastic modulus at a temperature of 23 ° C. and a relative humidity of 55% in the winding direction of the hard coat film is 3000 MPa or less,
The standard deviation of the film thickness distribution in the winding axis direction of the hard coat film peeled from the laminated film is 0.25 μm or less,
The laminated film roll, wherein the hard coat film peeled from the laminated film has a pencil hardness of 5B or more and less than H.

  [2] The laminated film roll according to [1], wherein the protective film is provided on the hard coat layer side of the hard coat film.

  [3] The laminated film roll according to [1] or [2], wherein the protective film is provided on the base layer side of the hard coat film.

  [4] The laminated film winding according to any one of [1] to [3], wherein a standard deviation of a film thickness distribution in a winding axis direction of the protective film peeled from the laminated film is 0.68 μm or less. Body.

  [5] The rolled laminated film according to any one of [1] to [4], wherein the protective film has self-adhesiveness.

  [6] The laminated film roll according to any one of [1] to [5], wherein a standard deviation of a film thickness distribution in a winding axis direction of the laminated film is 0.68 μm or less.

  [7] A laminate with a hard coat film, comprising a hard coat film peeled from the laminate film according to any one of [1] to [6] and an adherend.

  [8] The laminate with a hard coat film according to [7], wherein the hard coat film peeled off from the laminate film and the adherend are laminated via an adhesive layer.

  [9] A polarizing plate having a polarizing layer and a hard coat film peeled from the laminated film according to any one of [1] to [6].

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body with a hard coat film, such as a polarizing plate in which generation | occurrence | production of the streak was suppressed, can be provided.

(Laminated film roll)
The laminated film wound body of the present embodiment is a laminated film wound body in which the laminated film is wound in a roll shape. The laminated film has a hard coat film (hereinafter, sometimes referred to as “HC film”) and a protective film. The HC film has a base layer and a hard coat layer (hereinafter, may be referred to as “HC layer”). The HC film can be used, for example, as a protective layer for protecting the surface of the polarizing layer. For example, as described later, the HC film can be laminated on the polarizing layer to form a polarizing plate. The protective film is used as a protective layer for protecting the surface of the HC layer of the HC film, or in order to suppress the occurrence of blocking between the HC layer and the base layer when the HC film is wound. It can be used for. When a protective film is used to protect the surface of the HC layer, the protective film can be provided on the HC layer side of the HC film. In addition, when used to suppress the occurrence of blocking between the HC layer and the base layer, the protective film can be provided on the base layer side of the HC film. The protective film is usually provided on one side of the HC film, but may be provided on both sides of the HC film.

  In the laminated film roll, the thickness of the HC film is 30 μm or less. The thickness of the HC film may be 28 μm or less, 25 μm or less, 23 μm or less, and usually 8 μm or more, 10 μm or more, or 12 μm or more. You may. The thickness of the base layer contained in the HC film may be 29 μm or less, 25 μm or less, 20 μm or less, 5 μm or more, or 10 μm or more. You may. The thickness of the HC layer contained in the HC film may be 15 μm or less, may be 10 μm or less, may be 5 μm or less, may be 0.1 μm or more, and may be 0.5 μm or more. And may be 1 μm or more. In the HC film having the thickness in the above range, by setting the standard deviation of the film thickness distribution in the range described later, a streak generated on the HC film side of the laminate with the HC film can be suppressed. The thickness of the HC film can be measured by a method for measuring the thickness of the HC film described in Examples described later. Further, the thickness of the base material layer and the thickness of the HC layer can also be measured according to the method for measuring the thickness of the HC film described in Examples described later.

  Further, in the laminated film wound body, the tensile modulus at a temperature of 23 ° C. and a relative humidity of 55% in the winding direction (flow direction) of the HC film is 3000 MPa or less. The tensile modulus of the HC film may be 2800 MPa or less, 2500 MPa or less, and may be usually 800 MPa or more, 1000 MPa or more, or 1200 MPa or more. In the HC film having the tensile elastic modulus in the above range, by setting the standard deviation of the film thickness distribution in the range described later, a streak generated on the HC film side of the laminate with the HC film can be suppressed. The tensile modulus at a temperature of 23 ° C. and a relative humidity of 55% in the winding direction of the HC film can be measured by a method described in Examples described later.

  In the laminated film wound body, the standard deviation of the film thickness distribution in the winding axis direction (width direction) of the HC film peeled from the laminated film is 0.25 μm or less. The standard deviation of the film thickness distribution of the HC film may be 0.23 μm or less, may be 0.20 μm or less, and is usually 0.05 μm or more, and may be 0.1 μm or more. Good. The standard deviation of the film thickness distribution in the winding axis direction (width direction) of the HC film can be measured by a method described in Examples described later.

  The HC film obtained by unwinding the laminated film roll can be laminated on an adherend such as a polarizing layer to form a laminate with an HC film such as a polarizing plate. In a laminated body with an HC film in which an HC film obtained from a laminated film obtained by unwinding a laminated film wound body is laminated on an adherend, streaks may be visually recognized on the HC film side. The present inventors have found that when the thickness of the HC film is 30 μm or less and the tensile elastic modulus is 3000 MPa or less, it is likely to occur. Since the streaks generated in the HC film cannot be eliminated by post-treatment such as heating due to the presence of the HC layer, it is desirable to suppress the occurrence of streaks in the HC film obtained from the laminated film roll. It is. Investigation was carried out to suppress the streaks visible in the HC film. As a result, the standard deviation of the film thickness distribution in the winding axis direction of the HC film obtained from the laminated film obtained by unwinding the laminated film roll was 0.1. It has been found that streaks visible in a laminate with an HC film can be suppressed by using a layer having a thickness of 25 μm or less.

  When the standard deviation of the film thickness distribution in the winding axis direction of the HC film is 0.25 μm or less, it is not clear why the streaks are visually recognized on the surface of the laminated body with the HC film. Guessed. The HC film obtained by unwinding the laminated film wound body, the state of the HC film before the protective film is provided (before the laminated film) (standard deviation of the film thickness distribution, etc.), the HC film and the protective film (The standard deviation of the thickness distribution of the protective film, the tension at the time of laminating the HC film and the protective film, etc.), the state of winding (the tension at the time of winding, It is considered that the shape has a shape reflecting the influence of various factors such as the degree of tightness of the winding.

  For example, when the standard deviation of the film thickness distribution of each film (HC film and protective film) before being made into a laminated film is large, the HC film obtained by unwinding the laminated film roll has a standard deviation of the film thickness distribution. Is considered to be larger. In addition, when the HC film and the protective film are bonded together or when the laminated film is wound, tension is usually applied to the film. It is considered that when tension is applied to a film having a large standard deviation, the standard deviation of the film thickness distribution becomes large. Further, the rolled laminated film is wound by being wound with air at the time of winding, and is tightly wound by gradually removing the wound air after winding. It is considered that the laminated film and each film constituting the laminated film are deformed in accordance with the tightening. In particular, when the standard deviation of the film thickness distribution of the laminated film or each film constituting the laminated film is large, the amount of air taken in at the time of winding tends to vary, and the degree of air release tends to be non-uniform. It is considered that the amount of deformation of each film constituting the laminated film is likely to be large.

  As described above, in the HC film obtained by unwinding the laminated film wound body, under the influence of the various factors described above, the entire film surface is partially deformed without being flat along the horizontal plane. It is thought that there is. In an HC film having a large standard deviation of the film thickness distribution in the winding axis direction, the amount of deformation of the deformed portion is large. In the laminate with the HC film obtained by laminating on the adherend, it is considered that streaks are easily visible on the surface.

  When the thickness of the HC film is small, or when the above-described tensile modulus is small, it is easily affected by the various factors described above. Easy to grow. Therefore, the use of the HC film having a thickness of 30 μm or less and the tensile elastic modulus of 3000 MPa or less and having a small standard deviation of the film thickness distribution in the winding axis direction generates a HC film in the laminate. Streaks can be suitably suppressed.

  In the case where the standard deviation of the film thickness distribution in the winding axis direction of the HC film separated from the laminated film of the laminated film roll is 0.25 μm or less, for example, the HC film or the protective film before being formed into a laminated film (For example, as the HC film before being formed into a laminated film, smaller than the standard deviation of the film thickness distribution of the HC film peeled from the laminated film of the laminated film roll). Or a protective film before being formed into a laminated film, which is smaller than the standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled off from the laminated film of the laminated film roll). Use a substrate layer with a small standard deviation of the film thickness distribution as a base layer before being made into an HC film. The base layer is coated on the base layer to form an HC layer. HC film that adjusts the viscosity of the photocurable resin composition to be cured, and adjusts the curing conditions (illuminance and light amount of irradiated light) when curing the photocurable resin composition applied on the base layer. By adjusting the laminating conditions (tension applied to the HC film and the protective film at the time of lamination) when obtaining the laminated film by laminating the protective film and the protective film, adjusting the tension when winding the laminated film, and the like. Can be.

  In the laminated film roll, the pencil hardness of the HC film separated from the laminated film may be less than H (softer than H), for example, F, HB, B, 2B, 3B, 4B. It is usually 5B or more. The pencil hardness of the HC film can be measured according to the pencil hardness test specified in JIS K5600-5-4: 1999. When the pencil hardness of the HC film is low, the HC film is susceptible to the various factors described above, and thus the amount of partial deformation of the HC film tends to increase. For this reason, by using an HC film having a pencil hardness of less than H and having a small standard deviation of the film thickness distribution in the winding axis direction, streaks generated in the laminate with the HC film can be suitably suppressed. The pencil hardness of the HC film can be adjusted by adjusting the material and thickness of the HC layer, the material and thickness of the base layer, and the like.

  In the laminated film wound body, the standard deviation of the film thickness distribution in the direction of the winding axis of the protective film peeled from the laminated film is preferably 0.68 μm or less, and may be 0.65 μm or less. .60 μm or less. The standard deviation of the film thickness distribution in the winding axis direction (width direction) of the protective film can be measured by a method described in Examples described later. When the standard deviation of the film thickness distribution in the winding axis direction of the protective film is large, it is estimated that the standard deviation of the film thickness distribution of the protective film before being bonded to the HC film is also large. Such a protective film is bonded to an HC film to form a laminated film, and when this is wound to form a laminated film roll, it is considered that the HC film is likely to cause the above-described deformation with a larger deformation amount. . Therefore, it is preferable that the standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film is small. The standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film of the laminated film roll adjusts the standard deviation of the film thickness distribution as the protective film before being formed into a laminated film (for example, As a protective film before being formed into a laminated film, a protective film peeled off from the laminated film of the laminated film roll is smaller than a standard deviation of a film thickness distribution in a winding axis direction of the protective film), an HC film and a protective film Can be adjusted by adjusting the laminating conditions (tension applied to the HC film or the protective film at the time of lamination) when obtaining a laminated film by laminating and laminating the laminated film. it can.

  When adjusting the tension (tension before lamination) applied to the protective film when the HC film and the protective film are laminated to obtain a laminated film, the tension is preferably 0.03 N / mm or more, It may be 0.04 N / mm or more, preferably 0.35 N / mm or less, more preferably 0.2 N / mm or less, and even more preferably 0.1 N / mm or less. It is particularly preferably 0.08 N / mm or less, and may be 0.06 N / mm or less. When the tension is small, the protective film is likely to meander and the transportability is likely to be reduced. When the tension is increased, the curl generated in the laminated film after laminating the protective film is likely to be large, so that the protective film is easily deformed, and the winding of the HC film peeled off from the laminated film of the laminated film roll. The standard deviation of the film thickness distribution in the direction of the rotation axis tends to increase.

  The tension (winding tension) when winding the laminated film can be, for example, 0.05 N / mm or more and 0.35 N / mm or less. When the winding tension is small, a winding deviation is likely to occur in the rolled laminated film. When the winding tension is increased, bumps (winding bumps) which are observed in a protruding shape along the circumferential direction in the laminated film wound body are likely to occur, and the HC film is likely to be deformed by winding.

  Further, the protective film forming the laminated film of the laminated film roll preferably has self-adhesiveness. In the present specification, the term "self-adhesive" refers to a property capable of adhering by itself without providing a means for adhering an adhesive layer or the like and maintaining the adhered state. A protective film having self-adhesiveness can reduce the overall thickness as compared with a protective film having an adhesive layer. Thus, the HC film on which the protective film is laminated is easily deformed under the influence of the various factors described above. Therefore, when using a HC film from a laminated film roll using a protective film having self-adhesiveness to obtain a laminate with an HC film, the standard deviation of the film thickness distribution in the winding axis direction is small as the HC film. By using such a material, streaks generated in the laminate with the HC film can be suitably suppressed.

  In the laminated film roll, the standard deviation of the film thickness distribution in the winding axis direction of the laminated film is preferably 0.68 μm or less, may be 0.65 μm or less, or 0.60 μm or less. Is also good. The standard deviation of the film thickness distribution in the winding axis direction (width direction) of the laminated film can be measured by a method described in Examples described later. When the standard deviation of the film thickness distribution in the winding axis direction of the laminated film is large, it is considered that the HC film has undergone the above-described deformation with a larger deformation amount. Is preferably small. The standard deviation of the film thickness distribution in the winding axis direction of the laminated film is to adjust the standard deviation of the film thickness distribution as an HC film or a protective film before being made into a laminated film. Adjusting the standard deviation of the film thickness distribution, adjusting the laminating conditions (tension applied to the HC film and the protective film at the time of lamination) when laminating the HC film and the protective film to obtain a laminated film, It can be adjusted by adjusting the tension at the time of winding.

(Laminated body with hard coat film (laminated body with HC film) and polarizing plate)
The laminated body with the HC film of the present embodiment includes the HC film peeled from the laminated film on which the above-described laminated film roll is unwound, and an adherend. The laminated body with the HC film is obtained by peeling the protective film from the laminated film on which the above-mentioned laminated film roll is unwound to obtain an HC film, and laminating the HC film and the adherend via an adhesive layer. Can be obtained by By using the HC film described above, it is possible to obtain a laminate with an HC film in which generation of streaks on the HC film side is suppressed.

  The adherend is not particularly limited as long as it is an article required to increase the surface hardness and prevent scratches on the surface. For example, an optical element such as a polarizing layer; a touch panel display; a panel of an image display device such as a liquid crystal display or an organic EL display; a front case, a rear case, and a battery of portable electronic devices such as a smartphone, a tablet terminal, a music player, and a notebook computer Cases; Lenses such as goggles and glasses; Optical recording media such as CDs, DVDs, and Blu-ray discs; Building material decorative sheets; Glass, headlights, exterior parts, interior parts, electrical parts, sunroofs, and the like for automobiles. In particular, by making the base layer constituting the HC film a transparent base material, it can be suitably used for optical applications such as optical elements, panels of image display devices, and optical recording media. When the adherend is a polarizing layer, a laminate with an HC film having a polarizing layer and an HC film can be used as a polarizing plate.

  Examples of the adhesive layer for laminating the HC film and the adherend include an adhesive layer using an adhesive, an adhesive layer using an adhesive layer, and the like. The number of adhesive layers is usually one, but may be two or more.

  When the laminate with an HC film is a polarizing plate (when the adherend is a polarizing layer), the polarizing layer and the HC film are preferably laminated via an adhesive layer. In the polarizing plate, the HC film may be provided on one side of the polarizing layer via an adhesive layer, or the HC film may be provided on both sides of the polarizing layer via an adhesive layer. In addition, an HC film is provided on one surface of the polarizing layer via an adhesive layer, and a substrate layer having no HC layer, for example, different from the HC film is protected on the other surface via an adhesive layer. It may be provided as a layer.

  Hereinafter, the details of the above-described laminated film wound body, the laminated body with the hard coat film, the polarizing plate, and the respective layers constituting these will be further described.

(Laminated film roll)
The laminated film wound body can be obtained by winding around a core, for example, such that a protective film side of the laminated film described later becomes an outer surface. The length of the laminated film wound body in the winding axis direction is not particularly limited, but is usually 800 mm or more and 2000 mm or less, may be 1000 mm or more, may be 1200 mm or more, and may be 1800 mm or less. Or 1500 mm or less. The diameter of the laminated film roll is not particularly limited, but is usually 50 mm or more and 1000 mm or less, may be 100 mm or more, may be 300 mm or more, may be 800 mm or less, and may be 500 mm or less. You may.

(Laminated film)
The length of the laminated film in the laminated film wound body in the winding axis direction (width direction) is, for example, 800 mm or more and 2000 mm or less, 1000 mm or more, 1200 mm or more, or 1800 mm. Or less than 1500 mm. In addition, the length (winding length) of the laminated film in the laminated film roll may be, for example, 1000 m or more and 5000 m or less, may be 1500 m or more, may be 2000 m or more, and may be 4500 m or less. Or 4000 m or less.

  The laminated film can be formed by laminating an HC film and a protective film. The protective film may be attached to the HC layer side or the base layer side of the HC film by utilizing the adhesiveness of the protective film (the adhesive layer when the protective film has an adhesive layer).

(Hard coat film (HC film))
The base material layer constituting the HC film is used for protecting the adherend surface and supporting the HC layer. The substrate layer is not particularly limited, but is preferably a resin film. When the HC film is used by being bonded to an optical film such as a polarizing layer, it is formed from a thermoplastic resin having excellent transparency, mechanical strength, heat stability, moisture barrier properties, isotropy, stretchability, and the like. It is preferable to use a resin film. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resins; polysulfone resins; polycarbonate resins; polyamides such as nylon and aromatic polyamides. Resin; Polyimide resin; Polyolefin resin such as polyethylene, polypropylene, ethylene / propylene copolymer; Cyclic polyolefin resin having cyclo- and norbornene structure (also referred to as norbornene-based resin); (meth) acrylic resin; Polyarylate resin; A polyvinyl alcohol resin, and a mixture thereof. In this specification, “(meth) acryl” means that either acryl or methacryl may be used. “(Meth)” such as (meth) acrylate has the same meaning.

  The HC layer constituting the HC film is used for increasing the surface hardness of the base material layer, preventing scratches on the surface, and the like. As a material for forming the HC layer, for example, a photocurable resin, a thermosetting resin, an electron beam curable resin, and the like can be given, and among them, the photocurable resin is preferable.

  As the photocurable resin, a (meth) acrylic photocurable resin is preferably used. For example, a polyfunctional (meth) acrylate; a polyfunctional urethanized (meth) acrylate, a polyol (meth) acrylate, and, if necessary, A photocurable mixture containing a (meth) acrylic polymer having an alkyl group containing two or more hydroxyl groups may be used. Among these, a photocurable mixture is preferable from the viewpoint of adhesiveness to the substrate layer and productivity.

  Examples of the polyfunctional (meth) acrylate include di- or tri- (meth) acrylate of trimethylolpropane, tri- or tetra- (meth) acrylate of pentaerythritol, and (meth) having at least one hydroxyl group in the molecule. Examples include a polyfunctional urethane (meth) acrylate which is a reaction product of an acrylate and a diisocyanate. These polyfunctional (meth) acrylates may be used alone or in combination of two or more.

  Examples of the polyfunctional urethane (meth) acrylate used in forming the photocurable resin mixture include (meth) acrylic acid and / or (meth) acrylate, polyol, and a diisocyanate. You. Specifically, by preparing a hydroxy (meth) acrylate having at least one hydroxyl group in the molecule from (meth) acrylic acid and / or (meth) acrylate and a polyol, and reacting this with a diisocyanate, Multifunctional urethanized (meth) acrylates can be produced. The polyfunctional urethane (meth) acrylate produced in this way has a function as the above-mentioned photocurable resin. In the production thereof, (meth) acrylic acid and / or (meth) acrylic acid ester may be used each alone or in combination of two or more. Similarly, polyol and diisocyanate may be used respectively. One type may be used or two or more types may be used in combination.

  As the (meth) acrylic ester used in forming the polyfunctional urethane (meth) acrylate, a chain or cyclic alkyl ester of (meth) acrylic acid can be used, and specific examples thereof include methyl ( Alkyl (meth) acrylates such as meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth) acrylate; cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate No.

  The polyol used for forming the polyfunctional urethane (meth) acrylate is a compound having at least two hydroxyl groups in the molecule, and specific examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, Diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4 -Trimethyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol ester of hydroxypivalic acid, cyclohexane dimethylol, 1,4-cyclohexanediol, spiro glycol, tricyclodecane dimethylol, Biscuit Phenol A, ethylene oxide-added bisphenol A, propylene oxide-added bisphenol A, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol, glucose And the like.

  The diisocyanate used when forming the polyfunctional urethane (meth) acrylate is a compound having two isocyanato groups (-NCO) in the molecule, and various aromatic, aliphatic or alicyclic diisocyanates are used. Specific examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalenediisocyanate, and 3,3′-dimethyl. -4,4'-diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and nuclear hydrogenated diisocyanate having an aromatic ring among these. .

  The (meth) acrylic polymer having an alkyl group containing two or more hydroxyl groups used in forming the photocurable resin mixture has an alkyl group containing two or more hydroxyl groups in one structural unit, Specific examples thereof include a polymer containing 2,3-dihydroxypropyl (meth) acrylate as a constituent unit and a polymer containing 2,3-dihydroxypropyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate as a constituent unit And the like.

  The (meth) acrylic photocurable resin is preferably used as a photocurable resin composition in combination with a photopolymerization initiator. To the photocurable resin composition, if necessary, additives such as a leveling agent, an antioxidant, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent are added. You can also.

  The HC layer is obtained by applying a hard coat liquid containing a solvent (hereinafter, sometimes referred to as “HC liquid”) to one surface of the base material layer, drying the HC liquid, and further curing the dried HC liquid. Can be formed. The HC liquid can be prepared by adding and mixing a solvent to the photocurable resin composition. The solvent can be appropriately selected from organic solvents capable of dissolving components constituting the photocurable resin composition. The method for applying the HC liquid is not particularly limited, and a method known in the art, such as a method for applying using a bar coater, a method for applying by spraying using a spray or the like, can be used. The drying of the HC liquid applied to the base material layer can be performed by, for example, heat drying, vacuum drying, air drying, or the like. The method for curing the HC liquid after drying may be appropriately selected depending on the material for forming the HC layer, and examples thereof include a method of irradiating active energy rays such as ultraviolet rays and electron beams, and a method of heating.

(Protective film)
The protective film can be used to protect the surface of the HC layer of the HC film or to prevent the HC layer and the base material layer from blocking when the HC film is wound, and the like. May also be provided on the surface of the base material layer. The protective film preferably has a resin film, and when the resin film does not have self-adhesiveness, it may have an adhesive layer for bonding to the HC film. The resin film forming the protective film is not particularly limited, and examples thereof include a film formed from a thermoplastic resin for forming a base material layer forming an HC film. The self-adhesive protective film can be formed using, for example, a polypropylene-based resin and a polyethylene-based resin. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer that the protective film may have, for example, the following can be used.

  The thickness of the protective film is not particularly limited, but may be, for example, 5 μm or more and 200 μm or less, may be 10 μm or more, may be 20 μm or more, may be 25 μm or more, and may be 150 μm or less. May be 120 μm or less, or 100 μm or less. When the protective film has a pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer can be, for example, 5 μm or more and 100 μm or less, may be 10 μm or more, may be 15 μm or more, or 50 μm or less. And may be 40 μm or less. The thickness of the protective film or the pressure-sensitive adhesive layer can be measured according to the method for measuring the thickness of the HC film described in Examples described later.

(Polarizing layer)
The polarizing layer may be a layer in which a dichroic dye such as iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film (hereinafter sometimes referred to as a “PVA-based resin film”). It may be a layer in which dichroic dyes are oriented.

  The PVA-based resin film is a film formed using a polyvinyl alcohol-based resin. The polyvinyl alcohol-based resin refers to a resin containing 50% by mass or more of a structural unit derived from vinyl alcohol. As the polyvinyl alcohol resin, a resin obtained by saponifying a polyvinyl acetate resin can be used. The degree of saponification of the polyvinyl acetate resin can be determined in accordance with JIS K 6727 (1994), and can be, for example, in the range of 80.0 to 100.0 mol%.

  Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate with another monomer copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

  An example of the PVA-based resin film may be an unstretched film formed by forming a polyvinyl alcohol-based resin, or a stretched film obtained by stretching the unstretched film. When the PVA-based resin film is a stretched film, it is preferably a stretched film that has been stretched uniaxially in a longitudinal direction, and more preferably a stretched film that has been dry stretched. When the PVA-based resin film is a stretched film, the stretching ratio is usually 1.1 to 8 times.

  Examples of the polarizing layer, which is a layer in which the dichroic dye is oriented in the liquid crystal compound, include a cured layer in which the dichroic dye is oriented in the polymerizable liquid crystal compound and the polymerizable liquid crystal compound is polymerized. No. Such a polarizing layer is formed by coating a composition for forming a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye on a base film, and polymerizing and curing the polymerizable liquid crystal compound while maintaining a liquid crystal state. Can be formed. The polarizing layer thus obtained is in a state of being laminated on the base film, and the base film is provided as it is on the other surface of the polarizing layer (the surface opposite to the side on which the HC film is provided). It may be used as a protective layer. Alternatively, the base film may be peeled off after the polarizing layer with the base film capable of peeling the base film from the polarizing layer is laminated on the HC film via the adhesive layer.

(Adhesive layer)
Examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer include pressure-sensitive adhesives known as pressure-sensitive adhesives, and conventionally known pressure-sensitive adhesives can be used without any particular limitation. As the pressure-sensitive adhesive, for example, a pressure-sensitive adhesive having a base polymer of (meth) acrylic type, urethane type, silicone type, polyvinyl ether type or the like can be used. Further, an active energy ray-curable pressure-sensitive adhesive, a thermosetting pressure-sensitive adhesive or the like may be used. Among these, an adhesive using a (meth) acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (hereinafter also referred to as reworkability), weather resistance, heat resistance, and the like, is preferable.

(Adhesive layer)
The adhesive forming the adhesive layer can be formed, for example, by combining one or more of an aqueous adhesive, an active energy ray-curable adhesive, a pressure-sensitive adhesive and the like. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, a water-based two-part urethane emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, for example, those containing a polymerizable compound and a photopolymerizable initiator, those containing a photoreactive resin, Examples include those containing a binder resin and a photoreactive crosslinker. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable (meth) acrylic monomers, and photocurable urethane monomers, and oligomers derived from these monomers. . Examples of the photopolymerization initiator include those containing a substance that generates active species such as neutral radicals, anion radicals, and cation radicals when irradiated with active energy rays such as ultraviolet rays.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Measurement of thickness of hard coat film (HC film)]
Using a contact-type film thickness meter (Digimicro MH-15M, manufactured by Nikon Corporation), the sum of the position 50 mm inside both ends in the winding axis direction (width direction) of the HC film and the center position in the width direction. The thickness at three locations was measured, and the average value was taken as the thickness of the HC film.

[Measurement of tensile modulus of hard coat film (HC film)]
A rectangular test piece having a length of 100 mm in the winding direction (the length direction of the HC film) × a length of 25 mm in the winding axis direction (the width direction of the HC film) is cut out from the center in the winding axis direction of the HC film. Was. Next, each of the cut test pieces was gripped vertically by a tensile tester (AUTOGRAPH AG-1S tester manufactured by Shimadzu Corporation) so that the distance between the grips was 5 cm in the long side direction ( Winding direction) The test piece was pulled in the long side direction at a tensile speed of 1 mm / min under an environment of a temperature of 23 ° C. and a relative humidity of 55% with both ends sandwiched. The tensile modulus [MPa] in MD at ° C was calculated.

[Measurement of standard deviation of film thickness distribution]
With respect to the HC film, the protective film, and the laminated film obtained from the laminated film roll, the standard deviation of the film thickness distribution in the winding axis direction was measured by the following procedure. From one end in the winding axis direction (width direction) of each film using a non-contact type continuous film thickness meter (table-top offline capacitance thickness measuring device TOF-C, manufactured by Yamabun Electric Co., Ltd.) The thickness was measured at a pitch of 1 mm up to the other end (width 1330 mm), and a standard deviation was calculated from the measured value.

[Measurement of pencil hardness]
The pencil hardness of the HC film was measured according to a pencil hardness test specified in JIS K5600-5-4: 1999 on a glass plate so that the HC layer side was on the top.

[Example 1]
The protective film is laminated on the HC layer of the HC film so that the tension of the protective film (tension before lamination) is 0.045 N / mm, and the obtained laminated film is wound to form a laminated film wound body ( 1) was prepared. The protective film was a self-adhesive polyethylene film (FF1035, manufactured by Toledeger, 28 μm in thickness). In the HC film, the base layer was a (meth) acrylic resin film having a thickness of 25 μm, and the HC layer was a layer of a (meth) acrylic ultraviolet curable resin having a thickness of 3 μm. The thickness, tensile modulus, standard deviation of film thickness distribution, and pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (1) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (1) and the protective film peeled from the laminated film was measured. Table 1 shows the results.

  Next, as a polarizing layer, a polyvinyl alcohol-based resin film (PVA-based resin film) in which iodine as a dichroic dye was adsorbed and oriented was prepared. The polarizing film (1) is obtained by laminating the base layer side of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (1) on the polarizing layer using an aqueous adhesive. Was. As the above-mentioned water-based adhesive, a polyvinyl alcohol powder (trade name “GOSEFIMER” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average degree of polymerization: 1100) was dissolved in hot water at 95 ° C. to obtain a concentration of 3 wt. % Polyvinyl alcohol aqueous solution, an aqueous solution obtained by mixing a crosslinking agent [sodium glyoxylate manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] at a ratio of 1 part by weight to 10 parts by weight of polyvinyl alcohol powder was used. The thickness of the adhesive layer was 0.1 μm. When the obtained polarizing plate (1) was visually observed from the HC film side, no streak was visually recognized.

[Comparative Example 1]
A laminated film roll (2) was prepared in the same manner as in Example 2 except that the tension of the protective film (tension before lamination) was adjusted to be 0.090 N / mm. The thickness, tensile modulus, standard deviation of film thickness distribution, and pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (2) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (2) and the protective film peeled from the laminated film was measured. Table 1 shows the results.

  Next, a polarizing plate (2) was obtained in the same procedure as in Example 1. When the obtained polarizing plate (2) was visually observed from the HC film side, streaks in the direction along the winding direction in the laminated film roll (2) were visually recognized.

[Reference Example 1]
The same procedure as in Comparative Example 1 was carried out except that the base material layer was a 25 μm-thick triacetyl cellulose film and the HC layer was a 3 μm-thick (meth) acrylic UV-curable resin layer. Thus, a laminated film roll (3) was prepared. The thickness, tensile elastic modulus, standard deviation of film thickness distribution, and pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (3) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (3) and the protective film peeled from the laminated film was measured. Table 1 shows the results.

  Next, a polarizing plate (3) was obtained in the same procedure as in Example 1. When the obtained polarizing plate (3) was visually observed from the HC film side, no streak was visually recognized.

Claims (9)

A laminated film wound body in which the laminated film is wound into a roll,
The laminated film has a hard coat film having a base layer and a hard coat layer, and a protective film,
The thickness of the hard coat film is 30 μm or less,
The tensile elastic modulus at a temperature of 23 ° C. and a relative humidity of 55% in the winding direction of the hard coat film is 3000 MPa or less,
The standard deviation of the film thickness distribution in the winding axis direction of the hard coat film peeled from the laminated film is 0.25 μm or less,
A laminated film roll, wherein a pencil hardness measured from the hard coat layer side of the hard coat film peeled from the laminated film is 5B or more and less than H.   The laminated film roll according to claim 1, wherein the protective film is provided on the hard coat layer side of the hard coat film.   The laminated film roll according to claim 1, wherein the protective film is provided on the base layer side of the hard coat film.   The laminated film wound body according to any one of claims 1 to 3, wherein a standard deviation of a film thickness distribution in a winding axis direction of the protective film peeled from the laminated film is 0.68 µm or less.   The laminated film roll according to any one of claims 1 to 4, wherein the protective film has self-adhesiveness.   The laminated film wound body according to any one of claims 1 to 5, wherein a standard deviation of a film thickness distribution in a winding axis direction of the laminated film is 0.68 µm or less.   A laminate with a hard coat film, comprising a hard coat film peeled from the laminate film according to any one of claims 1 to 6 and an adherend.   The laminate with a hard coat film according to claim 7, wherein the hard coat film peeled from the laminate film and the adherend are laminated via an adhesive layer.   A polarizing plate comprising: a hard coat film peeled from the laminated film according to claim 1; and a polarizing layer.