CN108693588A - Polarization plates with protecting film and optical laminate - Google Patents

Abstract

The present invention provides a polarizing plate with a protective film capable of suppressing the mixing of air bubbles that may be generated when the protective film is attached back, and an optical laminate including the same. Provided is a polarizing plate with a protective film and an optical laminate comprising the same. The polarizing plate with a protective film includes: a polarizing plate including a polarizer, and a protective film laminated on one surface of the polarizing plate. Post back time is more than 17 seconds. Regarding the sticking back time, the end of one short side of a measurement sample of 100 mm in length x 50 mm in width obtained from a polarizing plate with a protective film was fixed, and the protective film of the measurement sample was peeled off from the short side opposite to the short side. When the protective film is pulled up at a specified pulling angle and length, the protective film is released from this state from the time of release to the time when the protective film is attached back to the polarizing plate of the measurement sample due to its own weight. The time of is defined as postback time.

Description

Polarizing plate and optical laminate with protective film

technical field

The present invention relates to a polarizing plate with a protective film and an optical laminate.

Background technique

Polarizing plates have been widely used in image display devices such as liquid crystal display devices, especially in various mobile devices such as smartphones in recent years. Conventionally, as a polarizing plate, a polarizing plate in which a dichroic dye is adsorbed and aligned on a polyvinyl alcohol-based resin film is bonded with a protective film to one or both surfaces.

A polarizing plate is generally distributed on the market as a polarizing plate with a pellicle in which a peelable pellicle (also referred to as a surface protective film) is attached to the surface to prevent contamination or damage of the surface. In addition, the manufacture or transportation of optical members such as liquid crystal panels including polarizing plates is also generally performed in a state in which a pellicle is attached to the surface of the polarizing plate.

Japanese Patent Application Laid-Open No. 2012-241108 (Patent Document 1) describes that a first adhesive layer with a relatively high surface resistivity and a second adhesive layer with a relatively low surface resistivity are laminated on a base film. A surface protective film is attached to the surface of the polarizing plate.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2012-241108

Contents of the invention

The problem to be solved by the invention

A pellicle attached to the surface of an optical member such as a polarizing plate may be temporarily peeled off during a performance inspection or an appearance inspection of the optical member, and may be attached back to the surface after the inspection. However, air bubbles may be mixed between the protective film and the optical member at the time of attachment. For example, when a polarizing plate with a pellicle with air bubbles mixed in when the pellicle is attached back is stored for a certain period of time before use, the shape of the air bubbles may be transferred into spots on the surface of the polarizing plate, which may cause the appearance of the polarizing plate to be damaged. bad.

An object of the present invention is to provide a polarizing plate with a pellicle that can suppress the incorporation of air bubbles that may be generated when the pellicle is attached back. Another object of the present invention is to provide an optical laminate including the polarizing plate with a protective film.

Solution to the problem

The present invention provides a polarizing plate with a protective film and an optical laminate shown below.

[1] A polarizing plate with a protective film comprising: a polarizing plate comprising a polarizer; and a protective film laminated on one surface of the polarizing plate,

The sticking back time of the protective film is more than 17 seconds,

With regard to the sticking back time, the end of one short side of the measurement sample with a size of 100 mm in length x 50 mm in width obtained from the polarizing plate with a protective film was fixed, and the short side facing the short side was fixed. The protective film of the measurement sample is peeled off to the fixed position, thereby obtaining the following state, and when the protective film is released from this state, the time from the release to the time when the protective film is attached back to the measurement sample due to its own weight The time until the polarizing plate is defined as the sticking back time, the state is starting from the fixed position, pulling up the protective film of the measurement sample, so that the protective film is relative to the polarizing plate of the measurement sample The pull-up angle was 90°, and the pull-up length of the pellicle was 90 mm.

[2] The polarizing plate with a protective film according to [1], when the protective film is peeled off from one short side of the measuring sample at a speed of 330 mm/sec, the peeling rate of the polarizing plate of the measuring sample from the surface is The peeling voltage after 5 seconds from the peeling is taken as the peeling voltage on the polarizing plate side, and the peeling voltage on the surface of the pellicle of the measurement sample after 5 seconds from peeling is set as the peeling voltage on the pellicle side. , the total value of the peeling voltage on the polarizing plate side and the peeling voltage on the protective film side is in the range of -0.500 to 0.500 kV, wherein the measurement sample is a longitudinal A measurement sample of 100 mm x 50 mm in width.

[3] The polarizing plate with a protective film according to [1] or [2],

The polarizing plate further includes a thermoplastic resin film laminated on the polarizing plate via an adhesive layer or an adhesive layer,

The pellicle film is laminated on the surface of the thermoplastic resin film.

[4] The polarizing plate with a protective film according to [1] or [2],

The polarizing plate further includes: a thermoplastic resin film laminated on the polarizer via an adhesive layer or an adhesive layer; and a resin layer laminated on a surface of the thermoplastic resin film,

The protective film is laminated on the surface of the resin layer.

[5] The polarizing plate with a protective film according to any one of [1] to [4], wherein the protective film includes a base film and an adhesive layer laminated on the base film.

[6] An optical laminate comprising an image display element and the polarizing plate with a protective film according to any one of [1] to [5] laminated on the image display element.

Invention effect

It is possible to provide a polarizing plate with a protective film capable of suppressing the mixing of air bubbles that may be generated when the protective film is attached back, and an optical laminate including the same.

Description of drawings

FIG. 1 is a schematic cross-sectional view schematically showing an example of a polarizing plate with a pellicle.

FIG. 2 is a schematic cross-sectional view showing an example of a polarizing plate with a pellicle.

Fig. 3 is a schematic cross-sectional view showing another example of a polarizing plate with a pellicle.

Fig. 4 is a schematic cross-sectional view showing still another example of a polarizing plate with a pellicle.

5 is a schematic side view showing a state where the pellicle of a measurement sample is pulled up to 90° in the measurement of the sticking back time of the pellicle.

Detailed ways

Embodiments are shown below to describe the present invention in detail.

In addition, description of "A to B" (A and B are numerical values.) in this specification means "more than A and less than B" unless otherwise specified.

<Polarizing plate with protective film>

(1) Configuration of polarizing plate with protective film

FIG. 1 is a schematic cross-sectional view schematically showing an example of a polarizing plate with a pellicle. An example of a polarizing plate with a pellicle will be described with reference to FIG. 1 . The polarizing plate with a hood includes a polarizing plate 100 including a polarizer (not shown in FIG. 1 ), and a pellicle 60 laminated on one surface of the polarizing plate 100 . The surface of the polarizing plate 100 on the pellicle 60 side (the surface to which the pellicle 60 is attached) may be, for example, a surface of a protective film, another optical film, or a layer added to the film.

The other surface of the polarizing plate 100 , that is, the surface opposite to the surface on which the pellicle film 60 is laminated, is not particularly limited, and may be composed of, for example, the surface of the first adhesive layer 31 as shown in FIG. 1 . In this case, the outer surface of the first pressure-sensitive adhesive layer 31 (the other surface of the polarizing plate 100 ) may be laminated with a peelable separator 70 for temporarily protecting the surface.

In the example of FIG. 1, the pellicle film 60 is comprised from the base film 61 and the 2nd adhesive layer 62 laminated|stacked thereon, and is bonded and laminated|stacked on the polarizing plate 100 via this adhesive layer.

The polarizing plate 100 is a polarizing element including at least a polarizing plate, and usually includes a thermoplastic resin film attached to one or both sides thereof. The thermoplastic resin film may be a protective film for protecting a polarizer, another optical film having an optical function different from that of the polarizer, or the like. A thermoplastic resin film may be provided with the resin layer (for example, an optical layer) laminated|stacked on the surface. A thermoplastic resin film can be bonded to a polarizing plate via an adhesive layer or an adhesive layer.

The thickness of the polarizing plate 100 is not particularly limited, but is usually 200 μm or less, preferably 150 μm or less, more preferably 125 μm or less, from the viewpoint of thinning the polarizing plate with a pellicle. The thickness of the polarizing plate 100 is usually 30 μm or more, more typically 50 μm or more. In the case where one outermost layer of the polarizing plate 100 is the first adhesive layer 31 and the separator 70 is laminated thereon, the thickness of the polarizing plate 100 mentioned here does not include the thickness of the separator 70 .

The polarizing plate with a pellicle may be in the form of a strip (tape), or may be a roll formed of the same. The polarizing plate with a protective film may be in the form of a sheet. The sheet-like body can be obtained by, for example, cutting a long polarizing plate with a protective film after making it by a so-called roll-to-roll method, which refers to continuously unwinding from a film roll and then cutting it. The conveyed raw material film is laminated with other raw material films continuously unwound from a film roll in the same manner, and the obtained elongated laminated film is wound up into a roll shape.

The shape of the above-mentioned sheet-shaped body is not particularly limited, and may be a square, but is preferably a square shape having a long side and a short side, more preferably a rectangle. The length of the long side and short side is not particularly limited, but the long side of the sheet-shaped body is usually 50 mm to 1000 mm (preferably 500 mm or less), and the short side is usually 30 mm to 600 mm (preferably 300 mm or less).

Next, specific examples of the layer configuration of the polarizing plate 100 will be described with reference to FIGS. 2 to 4 , but the layer configuration is not limited to these examples. For example, the other surface of the polarizing plate, that is, the surface opposite to the surface on which the protective film 60 is laminated, is not limited to the first adhesive layer 31, and may be formed by the surface of another film or layer such as the aforementioned thermoplastic resin film.

The polarizing plate of the polarizing plate with protective film shown in FIG. The first adhesive layer 31. In the example of FIG. 2, the protective film 60 is laminated|stacked on the surface of the protective film 21 which is a thermoplastic resin film.

The polarizing plate of the polarizing plate with protective film shown in FIG. The first pressure-sensitive adhesive layer 31 and the brightness-improving film 50 as an optical film laminated on the outer surface of the protective film 21 via the third pressure-sensitive adhesive layer 32 .

In the example of FIG. 3, the pellicle film 60 is laminated|stacked on the surface of the brightness improvement film 50 which is a thermoplastic resin film.

The polarizing plate of the polarizing plate with protective film shown in FIG. 4 has the same polarizing plate as that shown in FIG. layer composition. In the example of FIG. 4, the pellicle film 60 is laminated|stacked on the surface of the brightness improvement film 50 which is a thermoplastic resin film.

Although illustration is omitted, bonding of the polarizing plate 10 and the protective films 21 and 22 can be performed using an adhesive, for example.

As mentioned above, thermoplastic resin films, such as a protective film and other optical films, may have the resin layer laminated|stacked on the surface. The resin layer may be a surface treatment layer (coating). The surface treatment layer is a layer formed by applying a coating liquid containing a curable resin or the like, and performing drying treatment and curing treatment as necessary. As the surface treatment layer, for example, a hard coat layer, an antiglare layer, a light diffusion layer, a retardation layer (retardation layer having a retardation value of 1/4 wavelength, etc.), an antireflection layer, a low refractive index layer, an antireflection layer, etc. Static layer, anti-fouling layer, etc. The pellicle 60 may also be laminated on the surface of the resin layer.

For example, in the example of FIG. 2, the protective film 21 may have a surface treatment layer, and the protective film 60 may be laminated|stacked on the surface of this surface treatment layer (resin layer). In addition, in the example of FIG. 3, FIG. 4, the brightness improvement film 50 may have a surface treatment layer, and the pellicle film 60 may be laminated|stacked on the surface of this surface treatment layer (resin layer).

As another example of the layer structure of a polarizing plate, the structure which omitted the protective film, for example, the protective film 22 in the example of FIGS. 2-4 is mentioned. In this case, the first pressure-sensitive adhesive layer 31 is directly laminated on the surface of the polarizing plate 10 .

(2) The time to attach the protective film back

In the polarizing plate with a pellicle of the present invention, the sticking back time of the pellicle is 17 seconds or more. The inventors of the present invention have clarified that a polarizing plate with a protective film exhibiting a reattachment time of 17 seconds or more is less likely to cause air bubbles to be mixed into the protective film and the surface of the polarizing plate when the protective film is temporarily peeled off from the surface of the polarizing plate and then attached to the surface of the polarizing plate. between polarizing plates. Suppression of air bubbles contributes to the suppression of the above-mentioned spot-like defects on the surface of the polarizing plate, and further suppresses the poor appearance of the polarizing plate.

From the viewpoint of suppressing the inclusion of air bubbles, the sticking time of the pellicle is preferably 20 seconds or more, more preferably 25 seconds or more. The sticking time of the pellicle is usually 100 seconds or less, preferably 80 seconds or less, more preferably 50 seconds or less.

The return time of the protective film is defined as: take a measurement sample (sheet) of a specified size (100 mm in length x 50 mm in width) from a polarizing plate with a protective film, and fix one of its short side ends on a flat fixed table, such as As shown in Figure 5, starting from the fixed position, the pellicle is pulled up with a predetermined pull-up length (peeling length from the polarizing plate constituting the measurement sample), so that the pull-up angle relative to the polarizing plate of the measurement sample is When the pellicle becomes 90° and the pellicle is released from this state, it is the time from when the pellicle is released to when the pellicle is attached back to the polarizing plate of the measurement sample by its own weight. The starting point of the sticking back time is the moment when the state of pulling the pellicle to 90° is released. The end point of the sticking back time is the time when the end of the pellicle (the end on the short side facing the fixed short side) comes into contact with the polarizing plate of the measurement sample.

A more detailed measurement method of the sticking back time is as described in the Examples section described later.

(3) The peeling voltage of the polarizing plate with protective film

When the protective film is peeled off at a predetermined speed (330 mm/sec) from one short side of the measurement sample (sheet-shaped body), the peeling voltage of the polarizing plate surface of the measurement sample after 5 seconds from the peeling is set to " Polarizing plate side peeling voltage", and when the peeling voltage on the surface of the peeled pellicle 5 seconds after peeling is set as "protective film side peeling voltage", the polarizing plate side peeling voltage and pellicle side The total value (sum) of the peeling voltages is preferably in the range of -0.500 to 0.500 kV, wherein the measurement sample is a measurement sample of a predetermined size (100 mm long x 50 mm wide) obtained from a polarizing plate with a pellicle.

As a result of the study by the present inventors, it has become clear that when the above-mentioned total value (sum) is within the above-mentioned range, the above-mentioned predetermined or preferable post-return time tends to be sufficient. From the viewpoint of further improving the tendency to make the prescribed or preferred return time more likely to be sufficient, the above-mentioned total value (sum) is more preferably in the range of -0.300 to 0.300 kV, and even more preferably in the range of -0.150 to 0.150 kV It is particularly preferably in the range of -0.020 to 0.020kV. More detailed measurement methods of the "polarizing plate side peeling voltage" and "cover film side peeling voltage" are as described in the Examples section described later.

It is particularly worth mentioning that, compared with the single value of "polarizing plate side peeling voltage" or "protective film side peeling voltage", it is the total value of polarizing plate side peeling voltage and protective film side peeling voltage ( and ) have a strong correlation with the degree of air bubble mixing. The total value (sum) of the peeling voltage on the polarizing plate side and the peeling voltage on the pellicle side depends at least on the composition (including material.) of the pellicle and the composition (including material.) of the members constituting the polarizing plate attached to the pellicle both.

(4) Paste back time control

As described above, one means for controlling the sticking back time within the predetermined or preferable range is to adjust the total value (sum) of the peeling voltage on the polarizing plate side and the peeling voltage on the pellicle side to within the above range. However, postback time depends not only on this total value but also on other factors. As another factor, the thickness of a pellicle is mentioned, for example. The larger the thickness of the pellicle, the shorter the sticking time, and the smaller the thickness of the pellicle, the worse the sticking time.

As a means of adjusting the total value (sum) of the peeling voltage on the polarizing plate side and the peeling voltage on the pellicle side to the above-mentioned range, it is possible to include an antistatic agent in a polarizing plate with a pellicle. Among them, regarding the amount of antistatic agent added, it is preferable to consider the location where the antistatic agent is contained, the type of antistatic agent, etc., and to make the total value (sum) of the peeling voltage on the polarizing plate side and the peeling voltage on the protective film side reach the above-mentioned value. way to set the appropriate amount within the range. For example, a pellicle, a film or layer constituting the surface of the polarizing plate to which the pellicle is attached (for example, the surface of a thermoplastic resin film, the surface of a resin layer (surface treatment layer) laminated on the surface, etc.), or their Both contain antistatic agents. Preferably, the pellicle contains an antistatic agent.

It should be noted that, in the case of a polarizing plate with a protective film in which a low-refractive index layer is formed on the surface of a thermoplastic resin film constituting a polarizing plate, and a protective film is bonded to the surface of the low-refractive index layer, an antistatic film may be used. It is not easy to adjust the total value (sum) of the peeling voltage on the polarizing plate side and the peeling voltage on the pellicle side within the above range. From such a viewpoint, it is preferable that the film constituting the surface of the polarizing plate on which the pellicle is attached does not have a low-refractive index layer, and the reflectance Y value of the film is preferably 2% or more. That is, when the reflectance Y value of the aforementioned film is 2% or more, air bubbles are less likely to be introduced when the pellicle is attached back. The method of measuring the reflectance Y value follows the description in the Examples section described later.

(5) Polarizer

The polarizing plate 10 constituting the polarizing plate of the polarizing plate with a pellicle absorbs linearly polarized light having a vibration plane parallel to its absorption axis and has a vibration plane perpendicular to the absorption axis (parallel to the transmission axis). As an absorbing polarizing plate that transmits linearly polarized light, a polarizing film in which a dichroic dye is adsorbed and oriented to a uniaxially stretched polyvinyl alcohol-based resin film can be suitably used for the polarizing plate 10 . The polarizing plate 10 can be produced, for example, by a method including the steps of uniaxially stretching a polyvinyl alcohol-based resin film; dyeing the polyvinyl alcohol-based resin film with a dichroic dye so that the dichroic dye is adsorbed; The step of treating the polyvinyl alcohol-based resin film on which the dichroic dye is adsorbed with a cross-linking solution such as boric acid aqueous solution; and the step of washing with water after the treatment with the cross-linking solution.

As the polyvinyl alcohol-based resin, a resin obtained by saponifying polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers that can be copolymerized therewith, and the like. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having ammonium groups, and the like.

In this specification, "(meth)acryl" means at least one selected from acryl and methacryl. The same applies to "(meth)acryloyl", "(meth)acrylate", and the like.

The saponification degree of polyvinyl alcohol-type resin is 85-100 mol% normally, Preferably it is 98 mol% or more. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

A film obtained by forming such a polyvinyl alcohol-based resin into a film can be used as a raw film of the polarizing plate 10 (polarizing film). The method of forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a known method can be employed. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but in order to make the thickness of the polarizing plate 10 15 μm or less, it is preferable to use a thickness of 5 to 35 μm. More preferably, it is 20 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing of the dichroic dye, simultaneously with dyeing, or after dyeing. When performing uniaxial stretching after dyeing, this uniaxial stretching may be performed before crosslinking treatment or during crosslinking treatment. In addition, uniaxial stretching may be performed in the above-mentioned plural steps.

In the case of uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using heated rolls. In addition, the uniaxial stretching may be a dry stretching in which stretching is performed in the air, or a wet stretching in which a polyvinyl alcohol-based resin film is swollen using a solvent or water may be used. The draw ratio is usually 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing this film in the aqueous solution containing a dichroic dye is employable, for example. As a dichroic dye, iodine and a dichroic organic dye can be used. In addition, it is preferable that the polyvinyl-alcohol-type resin film performs the immersion process in water before dyeing process.

As a crosslinking treatment after dyeing with a dichroic dye, a method of immersing a dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid is generally employed. When using iodine as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide.

More preferably, the thickness of the polarizing plate 10 is usually 30 μm or less, preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less. In particular, setting the thickness of the polarizing plate 10 to 15 μm or less is advantageous in reducing the thickness of the polarizing plate with a pellicle. The thickness of the polarizing plate 10 is usually 2 μm or more.

(6) Protective film

The protective films 21, 22 that can be laminated on one or both sides of the polarizing plate 10 can be made of a light-transmitting (preferably optically transparent) thermoplastic resin, such as a chain polyolefin-based resin (polypropylene-based resin, etc.), Polyolefin-based resins such as cyclic polyolefin-based resins (norbornene-based resins, etc.); cellulose-based resins such as triacetylcellulose and diacetylcellulose; polyethylene terephthalate, polyethylene Polyester-based resins such as butylene terephthalate; polycarbonate-based resins; (meth)acrylic resins such as methyl methacrylate-based resins; polystyrene-based resins; polyvinyl chloride-based resins Resin; acrylonitrile-butadiene-styrene resin; acrylonitrile-styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin; polyamide resin; polyacetal resin; modified poly Films formed of phenylene ether resins; polysulfone resins; polyethersulfone resins; polyarylate resins; polyamideimide resins; polyimide resins, etc.

As the chain polyolefin resin, in addition to polyethylene resin (polyethylene resin as a homopolymer of ethylene, copolymer mainly composed of ethylene), polypropylene resin (polypropylene resin as a homopolymer of propylene, propylene In addition to the homopolymers of chain olefins such as the main copolymer), copolymers containing two or more kinds of chain olefins are also exemplified.

Cyclic polyolefin-based resins are a general term for resins polymerized with cyclic olefins as polymerization units, and examples include JP-A-1-240517, JP-A-3-14882, JP-A-3-122137 Resins described in gazettes, etc. Specific examples of cyclic polyolefin-based resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, and copolymerization of cyclic olefins with chain olefins such as ethylene and propylene. (representatively random copolymers), graft polymers modified with unsaturated carboxylic acids or derivatives thereof, and hydrogenated products thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

The polyester-based resin is a resin having an ester bond other than the cellulose ester-based resin described below, and is generally a resin containing a polycondensate of a polycarboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or its derivative, dibasic dicarboxylic acid or its derivative can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalate. Dihydric diols can be used as the polyhydric alcohol, and examples thereof include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, and cyclohexanedimethanol. As a representative example of polyester-based resin, polyethylene terephthalate which is a polycondensate of terephthalic acid and ethylene glycol is mentioned.

A (meth)acrylic resin is resin whose main constituent monomer is a compound which has a (meth)acryloyl group. Specific examples of (meth)acrylic resins include, for example: poly(meth)acrylates such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate- (meth)acrylate copolymer; methyl methacrylate-acrylate-(meth)acrylic acid copolymer; (meth)methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate and Copolymers of compounds having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). It is preferable to use a poly(meth)acrylate C _1-6 alkyl ester as a main component polymer such as poly(meth)acrylate, more preferably to use methyl methacrylate as a main component (50 to 100 % by weight, preferably 70 to 100% by weight) of methyl methacrylate resin.

Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of cellulose ester-based resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, these copolymers and cellulose ester-based resins in which some hydroxyl groups are modified with other substituents are exemplified. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferred.

A polycarbonate-based resin is an engineering plastic including a polymer in which monomer units are bonded via carbonate groups.

It is also useful to control the retardation value of the protective film 21 and/or the protective film 22 to a value suitable for an image display device such as a liquid crystal display device. For example, in an in-plane switching (IPS) mode liquid crystal display device, it is preferable to use a film having a retardation value of substantially zero as the protective film 22 . The retardation value being substantially zero means that the in-plane retardation value R ₀ at a wavelength of 590nm is 10nm or less, the absolute value of the retardation value R _th in the thickness direction at a wavelength of 590nm is 10nm or less, and that at a wavelength of 480 to 750nm The absolute value of the retardation value R _th in the thickness direction at 15 nm or less.

For example, depending on the mode of the liquid crystal display device, the protective film 21 and/or the protective film 22 may be stretched and/or shrunk to give an appropriate retardation value. For example, for the purpose of viewing angle compensation, a phase difference layer (or film) of a single-layer or multi-layer structure may be used as the protective film 22 . In this case, the polarizing plate 100 may be an elliptically polarizing plate or a circular polarizing plate having a laminated structure including the polarizing plate 10 and a retardation layer, or a polarizing plate including a retardation layer and having a viewing angle compensation function, or the like.

The thickness of the protective films 21 and 22 is usually 1 to 100 μm, but is preferably 5 to 60 μm, more preferably 5 to 50 μm, from the viewpoint of strength, handleability, and the like. If the thickness is within this range, the polarizing plate 10 can be protected mechanically, and even if exposed to a humid environment, the polarizing plate 10 will not shrink, and stable optical characteristics can be maintained.

When protective films are bonded to both surfaces of the polarizing plate 10, these protective films may be composed of the same type of thermoplastic resin or may be composed of different types of thermoplastic resins. In addition, the thickness may be the same or different. In addition, they may have the same phase difference characteristics or may have different phase difference characteristics.

As mentioned above, at least one of the protective films 21, 22 may be equipped with a hard coat layer, an anti-glare layer, a light diffusion layer, and a retardation layer (with 1 /4 wavelength retardation layer, etc.), antireflection layer, low refractive index layer, antistatic layer, antifouling layer and other surface treatment layers (coatings).

From the viewpoint of suppressing the mixing of air bubbles between the pellicle film and the polarizing plate, the surface of the polarizing plate 100 on the pellicle 60 side (the surface to which the pellicle film 60 is bonded) is preferably the arithmetic mean roughness Ra according to JIS B 0601:2013 smaller. Specifically, Ra of the above-mentioned surface is preferably 0.3 μm or less, more preferably 0.2 μm or less, and still more preferably 0.15 μm or less. Ra of the above-mentioned surface is usually 0.001 μm or more, for example, 0.005 μm or more.

The protective films 21 and 22 can be bonded to the polarizing plate 10 via an adhesive layer, for example. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and a water-based adhesive or an active energy ray-curable adhesive is preferable.

Examples of the water-based adhesive include an adhesive containing a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Among them, it is preferable to use a water-based adhesive containing an aqueous solution of a polyvinyl alcohol-based resin. As the polyvinyl alcohol-based resin, in addition to a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate which is a homopolymer of vinyl acetate, it is also possible to use vinyl acetate and other monomers that can be copolymerized therewith. Polyvinyl alcohol-based copolymers obtained by saponification of bulk copolymers, or modified polyvinyl alcohol-based polymers obtained by partially modifying their hydroxyl groups. The water-based adhesive may contain crosslinking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine-based compounds, methylol compounds, isocyanate compounds, amine compounds, and polyvalent metal salts.

When using a water-based adhesive, it is preferable to perform a drying process for removing the water contained in a water-based adhesive after bonding the polarizing plate 10 and the protective films 21 and 22 together. After the drying step, for example, a curing step of curing at a temperature of 20 to 45° C. may be provided.

The above-mentioned active energy ray-curable adhesive is an adhesive containing a curable compound cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet-curable adhesive.

The aforementioned curable compound may be a cation polymerizable curable compound or a radical polymerizable curable compound. As a cationically polymerizable curable compound, for example, epoxy-based compounds (compounds having one or more epoxy groups in the molecule), oxetane-based compounds (compounds having one or more epoxy groups in the molecule) 2 or more oxetane rings), or a combination thereof. Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), radically polymerizable Other vinyl compounds with double bonds, or combinations thereof. A cationically polymerizable curable compound and a radically polymerizable curable compound may also be used together. An active energy ray-curable adhesive usually further contains a cationic polymerization initiator and/or a radical polymerization initiator for initiating the curing reaction of the above-mentioned curable compound.

When bonding the polarizing plate 10 and the protective films 21 and 22 , surface activation treatment may be given to at least one of these bonding surfaces in order to improve adhesiveness. Examples of surface activation treatment include corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, and ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.). Dry treatment such as water, acetone and other solvents such as ultrasonic treatment, saponification treatment, primer treatment and other wet treatment. These surface activation treatments may be performed alone or in combination of two or more.

When bonding protective films to both surfaces of the polarizing plate 10, the adhesives used for bonding these protective films may be the same type of adhesive or different types of adhesives.

(7) Other optical films

The polarizing plate 100 may include other optical films other than the polarizing plate 10 and the protective films 21 and 22, and representative examples thereof are the brightness improving film 50 and retardation film. When the polarizing plate 100 includes another optical film, the protective film 60 may be laminated on the surface of the optical film, or on the surface of a resin layer laminated on the optical film.

The brightness improving film 50 is also called a reflective polarizing film, and a polarization conversion element having a function of separating light emitted from a light source (backlight) into transmitted polarized light, reflected polarized light, or scattered polarized light can be used. By arranging the brightness improving film 50 on the polarizing plate 10 , the output efficiency of the linearly polarized light emitted from the polarizing plate 10 can be improved by using the retroreflected light (Japanese: re-reflected light) as reflected polarized light or scattered polarized light. The brightness improvement film 50 can be laminated|stacked on the polarizing plate 10 via the adhesive layer (3rd adhesive layer 32). Another film such as a protective film may be interposed between the polarizing plate 10 and the brightness improvement film 50 .

The brightness enhancement film 50 may be, for example, an anisotropic reflective polarizer. An example of an anisotropic reflective polarizer is an anisotropic multilayer film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction. A specific example is "DBEF" manufactured by 3M Corporation (see Japanese Patent Application Laid-Open No. 4-268505, etc.). Another example of an anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ/4 plate, and a specific example thereof is "PCF" manufactured by Nitto Denko Co., Ltd. (see JP-A-11-231130, etc.) . Still another example of an anisotropic reflective polarizer is a reflective grid polarizer, and a specific example is a metal grid reflective polarizer that emits reflected polarized light even in the visible light region by microfabrication of metal (refer to U.S. Patent No. 6,288,840 Instructions, etc.), a film obtained by adding metal fine particles to a polymer matrix and stretching it (see Japanese Patent Application Laid-Open No. 8-184701, etc.).

A surface activation treatment may be performed in advance on the bonding surface of the brightness improving film 50 to be bonded to the third pressure-sensitive adhesive layer 32 . Examples of surface activation treatment are as described above.

As described above, a hard coat layer, an anti-glare layer, a light diffusion layer, a retardation layer (a retardation layer having a retardation value of 1/4 wavelength, etc.), an antireflection layer, etc. can be provided on the outer surface of the brightness improving film 50. Surface treatment layers (coatings) such as low refractive index layers, antistatic layers, and antifouling layers. By forming such a layer, the adhesiveness with the backlight tape and the uniformity of a displayed image can be improved. The thickness of the brightness improving film 50 is usually 10 to 100 μm, preferably 10 to 50 μm, and more preferably 10 to 30 μm from the viewpoint of thinning the polarizing plate 100 .

(8) Adhesive layer

The first adhesive layer 31 can be used to bond the polarizing plate with a pellicle to an image display element (for example, a liquid crystal cell) or other optical members. The third adhesive layer 32 can be used to bond optical films constituting the polarizing plate 100 (for example, another optical film such as the brightness improving film 50 and the polarizing plate 10 or the protective film 21 ). The first adhesive layer 31 and the third adhesive layer 32 can be made of resins such as (meth)acrylic, rubber, urethane, ester, silicone, and polyvinyl ether. It is composed of an adhesive composition as the main component. Among them, an adhesive composition using a (meth)acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, etc., is preferable. The adhesive composition may be an active energy ray-curable type or a heat-curable type.

As the (meth)acrylic resin (base polymer) used in the adhesive composition, for example, butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate , Polymers or copolymers of one or more types of (meth)acrylates such as 2-ethylhexyl (meth)acrylate as monomers. As the base polymer, it is preferable to copolymerize polar monomers. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethyl A monomer having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as aminoethyl (meth)acrylate and glycidyl (meth)acrylate.

The adhesive composition may contain only the above-mentioned base polymer, but usually also contains a crosslinking agent. Examples of the crosslinking agent include: a metal ion having a divalent or higher valence and forming a metal carboxylate salt with a carboxyl group; a crosslinking agent that is a polyamine compound and forming an amide bond with a carboxyl group; Oxygen compounds or polyols, which form ester bonds with carboxyl groups; polyisocyanate compounds, which form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferable.

The active energy ray-curable adhesive composition has the property of being cured by being irradiated with active energy rays such as ultraviolet rays or electron beams, and has adhesiveness even before irradiating active energy rays, so that it can be adhered to a film or the like. The adherend is an adhesive composition that can be cured by irradiation with active energy rays to adjust the properties of the adhesive force. The active energy ray-curable adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable adhesive composition contains an active energy ray polymerizable compound in addition to the base polymer and the crosslinking agent. In addition, a photopolymerization initiator and a photosensitizer may be contained as needed.

The adhesive composition may contain fine particles, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, antistatic agents, tackifiers, fillers (metal powder, Other inorganic powders, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, anti-corrosion agents, photopolymerization initiators and other additives.

The first pressure-sensitive adhesive layer 31 and the third pressure-sensitive adhesive layer 32 can be formed by applying an organic solvent dilution of the above-mentioned pressure-sensitive adhesive composition on a base material and drying it. The base material may be the polarizing plate 10, the protective films 21, 22, other optical films such as the brightness improvement film 50, an isolation film (for example, the isolation film 70), and the like. In the case of using an active energy ray-curable adhesive composition, a cured product having a desired degree of curing can be obtained by irradiating the formed adhesive layer with active energy rays.

The thickness of the first adhesive layer 31 and the third adhesive layer 32 is usually 1 to 40 μm, from the viewpoint of reducing the thickness of the polarizing plate with a pellicle film and maintaining good processability while suppressing the dimensional change of the polarizing plate 100 From the viewpoint of the thickness, it is preferably 3 to 25 μm (for example, 3 to 20 μm, preferably 3 to 15 μm).

(9) Isolation film

The separator 70 is a film temporarily attached to protect the surface before the first adhesive layer 31 is bonded to an image display element (for example, a liquid crystal cell) or another optical member. The separator 70 is usually made of a thermoplastic resin film that has been subjected to release treatment on one side with a release agent such as silicone or fluorine, and the release-treated surface is bonded to the first adhesive layer 31 .

The thermoplastic resin constituting the separator 70 may be, for example, polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, polyethylene terephthalate, polyethylene naphthalate, or the like. polyester resin, etc. The same separator as above may be pasted on the surface of the third pressure-sensitive adhesive layer 32 to protect the surface before bonding an optical film such as the brightness improvement film 50 . The thickness of the isolation film 70 is, for example, 10 to 50 μm.

(10) Protective film

The pellicle film 60 may include a base film 61 and a second adhesive layer 62 laminated thereon. The protective film 60 is a film for protecting the surface of the polarizing plate 100, and usually, for example, after the polarizing plate with the protective film is bonded to an image display element or other optical member, together with the second adhesive layer 62 it has are stripped and removed together.

The base film 61 is preferably a thermoplastic resin film. Examples of the thermoplastic resin constituting the thermoplastic resin film include polyolefin-based resins such as polyethylene-based resins and polypropylene-based resins; cyclic polyolefin-based resins; polyethylene terephthalate, polyethylene naphthalate Polyester resins such as glycol esters; polycarbonate resins; (meth)acrylic resins, etc. The base film 61 may have a single-layer structure or a multi-layer structure. The base film 61 preferably has a single-layer structure from the viewpoints of ease of manufacture, manufacturing cost, and the like.

The thickness of the base film 61 may be 20-150 μm (for example, 30-80 μm, preferably 30-60 μm), and the thickness of the protective film 60 may be 40-200 μm (for example, 50-160 μm). These thickness ranges are also advantageous in setting the reattachment time of the pellicle to the above-mentioned range. Regarding the configuration of the second adhesive layer 62 , the description about the above-mentioned first adhesive layer 31 and third adhesive layer 32 can basically be cited.

In particular, the storage elastic modulus of the second pressure-sensitive adhesive layer 62 is preferably 0.15 MPa or less at 80° C., more preferably 0.14 MPa or less, and still more preferably 0.10 MPa or less. Usually, the storage elastic modulus at 80° C. of the second pressure-sensitive adhesive layer 62 is 0.01 MPa or more. In the present specification, the storage elastic modulus of the pressure-sensitive adhesive layer can be measured using a commercially available viscoelasticity measuring device, for example, a viscoelasticity measuring device "DYNAMIC ANALYZER RDA II" manufactured by REOMETRIC Corporation.

The protective film 60 may contain an antistatic agent. For example, the second adhesive layer 62 may contain an antistatic agent. As an alternative to making the second adhesive layer 62 contain an antistatic agent, or at the same time, an antistatic agent may be provided on the surface of the base film 61 opposite to the surface on which the second adhesive layer 62 is laminated. Antistatic layer for static agents. By using the pellicle 60 containing an antistatic agent, the total value (sum) of the polarizing plate side peeling voltage and the pellicle side peeling voltage can be easily controlled within the above range. For the same reason, an antistatic agent may be added to the surface of the polarizing plate to which the protective film 60 is attached, or an antistatic layer may be formed. For example, an antistatic layer is formed on the thermoplastic resin film of the polarizing plate (the surface on which the protective film 60 is attached), or an antistatic layer is added to the resin layer (surface treatment layer) on the thermoplastic resin film of the polarizing plate. agent.

As an antistatic agent, an ionic compound is mentioned. An ionic compound is a compound having an inorganic cation or an organic cation, and an inorganic anion or an organic anion.

Two or more ionic compounds may also be used.

Examples of inorganic cations include alkali metal ions such as lithium cation [Li ⁺ ], sodium cation [Na ⁺ ], potassium cation [K ⁺ ], beryllium cation [Be ²⁺ ], magnesium cation [Mg ²⁺ ] , alkaline earth metal ions such as calcium cation [Ca ²⁺ ], etc.

Examples of organic cations include imidazolium cations, pyridinium cations, pyrrolidinium cations, ammonium cations, sulfonium cations, and phosphonium cations.

Among the above-mentioned cationic components, organic cationic components are preferably used because they have good compatibility with the adhesive composition.

Examples of inorganic anions include chloride anion [Cl ^- ], bromide anion [Br ^- ], iodide anion [I ^- ], tetrachloroaluminate anion [AlCl ₄ ^- ], heptachlorodialuminate anion [Al ₂ Cl ₇ ^- ], tetrafluoroborate anion [BF ₄ ^- ], hexafluorophosphate anion [PF ₆ ^- ], perchlorate anion [ClO ₄ ^- ], nitrate anion [NO ₃ ^- ], hexafluoroarsenate anion [ AsF ₆ ^- ], hexafluoroantimonate anion [SbF ₆ ^- ], hexafluoroniobate anion [NbF ₆ ^- ], hexafluorotantalate anion [TaF ₆ ^- ], dicyandiamide anion [(CN) ₂ N ^- ] Wait.

Examples of organic anions include: acetate anion [CH ₃ COO ^- ], trifluoroacetate anion [CF ₃ COO ^- ], methanesulfonate anion [CH ₃ SO ₃ ^- ], trifluoromethanesulfonate anion [CF ₃ SO ₃ ^- ], p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ^- ], bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N ^- ], bis(trifluoromethanesulfonate Acyl)imide anion [(CF ₃ SO ₂ ) ₂ N ^- ], tris(trifluoromethanesulfonyl)methanide anion [(CF ₃ SO ₂ ) ₃ C ^- ], dimethylphosphonite anion [( CH ₃ ) ₂ POO ^- ], (poly) hydrofluoric acid fluoride anion [F(HF) _n ^- ] (n is about 1 to 3), thiocyanate anion [SCN ^- ], perfluorobutanesulfonate anion [C ₄ F ₉ SO ₃ ^- ], bis(pentafluoroethanesulfonyl)imide anion [(C ₂ F ₅ SO ₂ ) ₂ N ^- ], perfluorobutyrate anion [C ₃ F ₇ COO ^- ], (Trifluoromethanesulfonyl)(trifluoromethanecarbonyl)imide anion [(CF ₃ SO ₂ )(CF ₃ CO)N ^- ], perfluoropropane-1,3-disulfonate anion [ ^- O ₃ S (CF ₂ ) ₃ SO ₃ ^- ], carbonate anion [CO ₃ ^2- ], etc.

Among the above-mentioned anionic components, anionic components containing fluorine atoms are particularly preferably used because they can provide ionic compounds excellent in antistatic performance. Specifically, bis(fluorosulfonyl)imide anion, hexafluorophosphate anion, or bis(trifluoromethanesulfonyl)imide anion can be mentioned.

Specific examples of the ionic compound can be appropriately selected from combinations of the above-mentioned cationic components and anionic components. When the examples of the ionic compound which has an organic cation are listed according to the structure of an organic cation, the following compounds are mentioned.

Pyridinium salt:

N-hexylpyridinium hexafluorophosphate,

N-octylpyridinium hexafluorophosphate,

N-octyl-4-methylpyridinium hexafluorophosphate,

N-butyl-4-methylpyridinium hexafluorophosphate,

N-decylpyridinium bis(fluorosulfonyl)imide,

N-dodecylpyridinium bis(fluorosulfonyl)imide,

N-tetradecylpyridinium bis(fluorosulfonyl)imide,

N-hexadecylpyridinium bis(fluorosulfonyl)imide,

N-dodecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-tetradecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-hexadecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-benzyl-2-methylpyridinium bis(fluorosulfonyl)imide,

N-benzyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-hexylpyridinium bis(trifluoromethanesulfonyl)imide,

N-octylpyridinium bis(trifluoromethanesulfonyl)imide,

N-octyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide,

N-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide.

Imidazolium salt:

1-ethyl-3-methylimidazolium hexafluorophosphate,

1-ethyl-3-methylimidazolium p-toluenesulfonate,

1-Ethyl-3-methylimidazolium bis(fluorosulfonyl)imide,

1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide,

1-Butyl-3-methylimidazolium methanesulfonate,

1-Butyl-3-methylimidazolium bis(fluorosulfonyl)imide.

Pyrrolidinium salt:

N-butyl-N-methylpyrrolidinium hexafluorophosphate,

N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide,

N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide.

Quaternary ammonium salt:

Tetrabutylammonium hexafluorophosphate,

Tetrabutylammonium p-toluenesulfonate,

(2-Hydroxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide,

(2-Hydroxyethyl)trimethylammonium dimethylphosphonite.

Moreover, if the example of the ionic compound which has an inorganic cation is given, the following compounds are mentioned.

lithium bromide,

lithium iodide,

lithium tetrafluoroborate,

lithium hexafluorophosphate,

lithium thiocyanate,

lithium perchlorate,

Lithium trifluoromethanesulfonate,

Lithium bis(fluorosulfonyl)imide,

Lithium bis(trifluoromethanesulfonyl)imide,

Lithium bis(pentafluoroethanesulfonyl)imide,

Lithium tris(trifluoromethanesulfonyl)methanide,

Lithium p-toluenesulfonate,

sodium hexafluorophosphate,

Sodium bis(fluorosulfonyl)imide,

Sodium bis(trifluoromethanesulfonyl)imide,

Sodium p-toluenesulfonate,

Potassium hexafluorophosphate,

Potassium bis(fluorosulfonyl)imide,

Potassium bis(trifluoromethanesulfonyl)imide,

Potassium p-toluenesulfonate.

It is also possible to form an antifouling agent based on a silicone-based, fluorine-based, etc. release agent or coating agent, silica particles, or the like on the surface of the base film 61 opposite to the surface on which the second adhesive layer 62 is laminated. Floor. The above-mentioned antistatic layer may also serve as an antifouling layer.

<Optical laminate, liquid crystal panel, and image display device>

The polarizing plate with a protective film can be suitably used for the optical laminated body which consists of an image display element and the polarizing plate with a protective film laminated|stacked thereon. In this optical laminate, the polarizing plate with a protective film can be bonded to (in the case of a separator such as the separator 70, peeled off) via an adhesive layer (for example, the first adhesive layer 31). After removal) the image is displayed on the component. The optical laminate may be a liquid crystal panel including an image display element and polarizing plates with protective films laminated on one or both surfaces thereof.

The image display device may be any device such as a liquid crystal display device or an organic EL display device, but it is preferable that the liquid crystal display device is a liquid crystal display device. A liquid crystal display device includes: a liquid crystal panel including a liquid crystal cell as an image display element; and a backlight. When constructing a liquid crystal display device, the polarizing plate with protective film of the present invention can be used for the polarizing plate arranged on the viewing side, also can be used for the polarizing plate arranged on the backlight side, and can also be used for the viewing side and the backlight Polarizing plates on both the source side.

[Example]

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these examples. In examples, % and parts showing content or usage-amount are based on weight unless otherwise specified. In addition, the thickness of a film was measured using the digital micrometer "MH-15M" made from Nikon Corporation.

<Production of Polarizer>

A polyvinyl alcohol film with a thickness of 20 μm (average degree of polymerization of about 2400, saponification degree of 99.9 mole percent or more) is longitudinally uniaxially stretched to about 5 times by dry stretching, and further, under the condition of maintaining tension, After immersing in 60 degreeC pure water for 1 minute, it immersed in the 28 degreeC aqueous solution whose weight ratio of iodine/potassium iodide/water was 0.05/5/100 for 60 seconds. Then, it was immersed for 300 seconds in the 72 degreeC aqueous solution whose weight ratio of potassium iodide/boric acid/water was 8.5/8.5/100. Next, after washing with pure water at 26° C. for 20 seconds, drying treatment was performed at 65° C. to obtain a polarizing plate having a thickness of 7 μm in which iodine was adsorbed and oriented to the polyvinyl alcohol film.

<Preparation of protective film A>

(1) Preparation of acrylic polymer

Nitrogen gas was introduced into a reaction device equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction pipe, and the air in the reaction device was replaced with nitrogen gas. Then, 60 parts of solvent (ethyl acetate), 93 parts of 2-ethylhexyl acrylate, 5.5 parts of 8-hydroxyoctyl acrylate, and 1.5 parts of acrylic acid were added to the reaction apparatus. Then, 0.1 part of azobisisobutyronitrile was added dropwise as a polymerization initiator over 2 hours, and it was made to react at 65 degreeC for 6 hours, and the polymer solution 1 was obtained. The weight-average molecular weight of the acrylic polymer contained in the polymer solution 1 was 500,000 (standard polystyrene conversion value based on gel permeation chromatography).

(2) Production of protective film A

After adding 2.0 parts of 1-octylpyridinium dodecylbenzenesulfonate as an antistatic agent to 100 parts of the acrylic polymer contained in the polymer solution 1 obtained in the above (1) and stirring, add CORONATE 1.5 parts of HX (isocyanurate body of a hexamethylene diisocyanate compound) were stirred and mixed to obtain an adhesive composition. After coating this adhesive composition on a separator with a thickness of 15 μm formed of a polyethylene terephthalate (PET) film coated with a silicone resin, it was dried at 90° C. The solvent was removed to obtain a PSA sheet having a PSA layer (storage modulus of elasticity at 80° C.: 0.09 MPa) having a thickness of 25 μm. Then, on the side opposite to the side of a polyethylene terephthalate (PET) film with a thickness of 38 μm that has been subjected to antistatic treatment and antifouling treatment on one surface An adhesive sheet was laminated on the surface of the film to obtain a protective film A having a layer composition of antistatic treatment and antifouling treatment PET film/adhesive layer/release film (PET film coated with silicone resin). Hereinafter, the adhesive layer included in the pellicle film A and the following pellicle films B to D is also referred to as a second adhesive layer.

A cylinder with a diameter of 8mm and a thickness of 1mm was used as a test piece, and the storage energy elasticity of the adhesive layer was measured at a temperature of 80°C by a torsional shear method with a frequency of 1 Hz using a viscoelasticity measuring device "DYNAMIC ANARYZER RDA II" manufactured by REOMETRIC Corporation. modulus. The same applies to the storage elastic modulus of the pressure-sensitive adhesive layer included in the pellicle below.

<Preparation of protective film B>

As the protective film B, a PET film (without antistatic ability) with a thickness of 38 μm, an adhesive layer with a thickness of 20 μm laminated thereon (the storage elastic modulus of the adhesive layer at 80° C. is 0.15 MPa), And a release film laminated on the surface of the adhesive layer, and the adhesive layer contains a protective film of antistatic agent.

<Preparation of protective film C>

As the protective film C, a PET film (without antistatic ability) with a thickness of 38 μm, an adhesive layer with a thickness of 15 μm laminated thereon (the storage elastic modulus of the adhesive layer at 80° C. is 0.12 MPa), And a release film laminated on the surface of the adhesive layer, and the adhesive layer contains a protective film of an antistatic agent.

<Preparation of Protective Film D>

As the protective film D, a PET film (without antistatic ability) with a thickness of 38 μm, an adhesive layer with a thickness of 15 μm laminated thereon (the storage elastic modulus of the adhesive layer at 80° C. is 0.16 MPa), And a release film laminated on the surface of the adhesive layer, and the adhesive layer does not contain a protective film of an antistatic agent.

<Preparation of the first protective film A>

As the first protective film A, a triacetyl cellulose film (thickness: 40 μm, brand name “KC4UY”) manufactured by Konica Minolta Co., Ltd. was prepared. The arithmetic mean roughness Ra of the bonding surface with the pellicle according to JIS B 0601:2013 is 0.0050 μm. The first protective film A does not contain an antistatic agent.

<Preparation of the first protective film B>

As the first protective film B, prepare an antireflection film (thickness: 40 μm, trade name "HLAG8" manufactured by Dainippon Printing Co., Ltd., including a base film formed of a triacetyl cellulose film, and an antiglare layer laminated thereon. , and a low refractive index layer laminated on the anti-glare layer). The arithmetic mean roughness Ra of the bonding surface with the pellicle (the surface of the low-refractive index layer) according to JIS B 0601:2013 was 0.0570 μm. The first protective film B does not contain an antistatic agent.

<Preparation of the first protective film C>

As the first protective film C, prepare a film manufactured by Toppan Printing Co., Ltd. (thickness 25 μm, trade name "25KCHC-TC", including a base film formed of a triacetyl cellulose film and a hard coat layer laminated thereon. ). The arithmetic mean roughness Ra of the bonding surface with the pellicle (the surface of the hard coat layer) according to JIS B 0601:2013 was 0.0140 μm. The first protective film C does not contain an antistatic agent.

<Preparation of the first protective film D>

As the first protective film D, prepare an antireflection film (thickness 40 μm, trade name "40KSPLR") manufactured by Toppan Printing Co., Ltd., including a base film formed of a triacetyl cellulose film, an antiglare layer laminated thereon, and a low refractive index layer laminated on the anti-glare layer). The arithmetic mean roughness Ra of the bonding surface with the pellicle (the surface of the low-refractive index layer) according to JIS B 0601:2013 was 0.0070 μm. The first protective film D contains an antistatic agent in the low refractive index layer.

<Preparation of the first protective film E>

As the first protective film E, prepare an anti-glare film (thickness 40 μm, trade name "GL-5150") produced by Dainippon Printing Co., Ltd., which includes a base film formed of a triacetyl cellulose film, and a film laminated thereon. anti-glare layer). The arithmetic mean roughness Ra of the bonding surface (surface of the anti-glare layer) with the pellicle according to JIS B 0601:2013 was 0.1300 μm. The first protective film E does not contain an antistatic agent.

<Measurement of the reflectance Y value of the first protective film>

About said 1st protective film A-E, the reflectance Y value was measured using the spectrophotometer ("UV2200" by Shimadzu Corporation). The reflectance Y value refers to the visual sensitivity correction (Japanese: visual sensitivity correction) reflectance. Specifically, it refers to the reflectance when light is incident at an incident angle of 12° using a 2-degree field of view (C light source) according to JIS Z 8701. Spectral reflectance in the wavelength range of 350 to 900 nm at an angle of 12° (that is, the regular reflectance at an incident angle of 12°) is the reflectance obtained by correcting visual sensitivity. In order to prevent reflection from the back of the protective film sample and prevent warping of the sample, use an optically transparent adhesive to place the sample on the side opposite to the bonding surface of the protective film (the bonding surface of the protective film becomes the surface) ) was bonded to a black acrylic plate ("SUMIPEX" manufactured by Sumitomo Chemical Co., Ltd.) and measured.

The measurement results of the reflectance Y value are shown below.

1st protective film A: 4%,

1st protective film B: 0.8%,

1st protective film C: 4%,

1st protective film D: 1%,

1st protective film E: 4%.

<Preparation of the second protective film>

A cyclic polyolefin-based resin film (thickness: 13 μm) manufactured by Nippon Zeon Co., Ltd. was prepared. The in-plane retardation value _Re of the film at a wavelength of 590nm is 0.8nm, the thickness direction retardation value _Rth at a wavelength of 590nm is 3.4nm, and the thickness direction retardation value _Rth at a wavelength of 483nm is 3.5nm, The retardation value R _th in the thickness direction at a wavelength of 755 nm was 2.8 nm. The phase difference value was measured at 23° C. using “KOBRA-ADH” manufactured by Oji Scientific Instruments Co., Ltd., which is a phase difference meter based on the parallel Nicol rotation method.

<Production of Brightness Improvement Film with Hard Coat>

A hard coat layer was formed on one surface of a 17-μm-thick brightness-improving film (trade name "Advanced Polarized Film, Version 4" manufactured by 3M Corporation) to obtain a 20-μm-thick brightness-improving film with a hard coat layer. The arithmetic mean roughness Ra of the bonding surface with the pellicle (the surface of the hard coat layer) according to JIS B0601:2013 was 0.0150 μm. The brightness-enhancing film of this hard coat layer does not contain an antistatic agent.

<Preparation of the first adhesive layer>

As the first pressure-sensitive adhesive layer, prepared was prepared an acrylic pressure-sensitive adhesive layer with a thickness of 20 μm on the release-treated surface of a release-treated separator made of polyethylene terephthalate with a thickness of 38 μm. Commercially available adhesive layer with release film.

<Preparation of the third adhesive layer>

Copolymer of butyl acrylate and acrylic acid, in which an organic solvent solution of urethane acrylate oligomer and isocyanate crosslinking agent was added, was applied to the The release-treated surface of the 38 μm-thick polyethylene terephthalate separator was subjected to the release treatment, and then dried to obtain a third pressure-sensitive adhesive layer with a release film.

<Preparation of water-based adhesive>

A polyvinyl alcohol aqueous solution was prepared by dissolving 3 parts of carboxy-modified polyvinyl alcohol ["KL-318" manufactured by Kuraray Corporation] with respect to 100 parts by weight of water. In the obtained aqueous solution, a water-soluble polyamide epoxy resin ["Sumires Resin 650 (30)" manufactured by Tagoka Chemical Industry Co., Ltd.] was mixed at a ratio of 1.5 parts to 100 parts of water, and the solid content concentration was 30%. ] to obtain a water-based adhesive.

<Example 1>

A polarizing plate with a pellicle having the same layer configuration as in Fig. 2 was produced in the following procedure. First, the first protective film A is bonded to one side of the polarizer using the water-based adhesive, and the second protective film is bonded to the other side in the same manner using the water-based adhesive. Before bonding, corona treatment of 15.9 kJ/m ² was given to the bonding surfaces of the first and second protective films and the polarizing plate. Then, it was dried at 80° C. for 5 minutes, and cured at 40° C. for 168 hours.

Next, the above-mentioned 1st pressure-sensitive adhesive layer (it has a separator film on the outer surface.) was bonded to the surface of the 2nd protective film on the side opposite to a polarizing plate. Before bonding, corona treatment of 15.9 kJ/m ² was given to both the bonding surface of the 2nd protective film and the bonding surface of the 1st pressure-sensitive adhesive layer. Furthermore, the said pellicle A was bonded to the surface of the 1st protective film opposite to a polarizing plate via the 2nd pressure-sensitive adhesive layer, and the polarizing plate with a pellicle was obtained.

<Example 2>

Except having used the said pellicle B instead of pellicle A, it carried out similarly to Example 1, and produced the polarizing plate with a pellicle.

<Example 3>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 1, and produced the polarizing plate with a pellicle.

<Comparative example 1>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 1, and produced the polarizing plate with a pellicle.

<Example 4>

A polarizing plate with a pellicle having the same layer configuration as in Fig. 4 was produced in the following procedure. First, the second protective film is bonded to one surface of the polarizing plate using the water-based adhesive. Before bonding, corona treatment of 15.9 kJ/m ² was given to the bonding surface with the polarizing plate of the 2nd protective film. Then, it dried at 80 degreeC for 5 minutes, and maintained at 40 degreeC for 168 hours. Next, the said 1st pressure-sensitive adhesive layer (it has a separator film on the outer surface.) was bonded to the surface of the 2nd protective film on the side opposite to a polarizing plate. Before bonding, corona treatment of 15.9 kJ/m ² was given to both the bonding surface of the 2nd protective film and the bonding surface of the 1st pressure-sensitive adhesive layer. Furthermore, the said 3rd pressure-sensitive adhesive layer (having a separator on the outer surface) was bonded to the surface of the polarizer opposite to the 2nd protective film. Before bonding, corona treatment of 15.9 kJ/m ² was given to both the bonding surface of the polarizing plate and the bonding surface of the third pressure-sensitive adhesive layer. Next, after peeling and removing the separator of the third pressure-sensitive adhesive layer, the above-mentioned brightness-improving film with a hard coat layer was bonded on the surface of the third pressure-sensitive adhesive layer exposed by peeling from the brightness-improving film side. Before bonding, corona treatment of 15.9 kJ/m ² was given to the bonding surface of the brightness improving film. Finally, the above-mentioned pellicle film A was bonded to the outer surface of the hard coat layer included in the brightness improving film via the second pressure-sensitive adhesive layer to obtain a polarizing plate with a pellicle film.

<Example 5>

Except having used the said pellicle B instead of pellicle A, it carried out similarly to Example 4, and produced the polarizing plate with a pellicle.

<Example 6>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 4, and produced the polarizing plate with a pellicle.

<Comparative example 2>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 4, and produced the polarizing plate with a pellicle.

<Example 7>

Except having used the said 1st protective film B instead of the 1st protective film A, it carried out similarly to Example 1, and produced the polarizing plate with a protective film.

<Embodiment 8>

Except having used the said pellicle B instead of pellicle A, it carried out similarly to Example 7, and produced the polarizing plate with a pellicle.

<Example 9>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 7, and produced the polarizing plate with a pellicle.

<Comparative example 3>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 7, and produced the polarizing plate with a pellicle.

<Example 10>

Except having used the said 1st protective film C instead of the 1st protective film A, it carried out similarly to Example 1, and produced the polarizing plate with a protective film.

<Example 11>

Except having used the said pellicle B instead of pellicle A, it carried out similarly to Example 10, and produced the polarizing plate with a pellicle.

<Example 12>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 10, and produced the polarizing plate with a pellicle.

<Comparative example 4>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 10, and produced the polarizing plate with a pellicle.

<Example 13>

Except having used the said 1st protective film D instead of the 1st protective film A, it carried out similarly to Example 1, and produced the polarizing plate with a protective film.

<Example 14>

Except having used the said pellicle B instead of pellicle A, it carried out similarly to Example 13, and produced the polarizing plate with a pellicle.

<Example 15>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 13, and produced the polarizing plate with a pellicle.

<Comparative example 5>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 13, and produced the polarizing plate with a pellicle.

<Example 16>

Except having used the said 1st protective film E instead of the 1st protective film A, it carried out similarly to Example 1, and produced the polarizing plate with a protective film.

<Example 17>

A polarizing plate with a pellicle was produced in the same manner as in Example 16 except that the pellicle B was used instead of the pellicle A.

<Example 18>

Except having used the said pellicle C instead of pellicle A, it carried out similarly to Example 16, and produced the polarizing plate with a pellicle.

<Comparative example 6>

Except having used the said pellicle D instead of pellicle A, it carried out similarly to Example 16, and produced the polarizing plate with a pellicle.

The obtained polarizing plate with a pellicle was measured and evaluated as follows. The results are shown in Table 1.

(1) Determination of the sticking back time of the protective film

From the obtained polarizing plate with a pellicle (the state in which the separator was laminated on the outer surface of the first pressure-sensitive adhesive layer), a sheet-shaped body having a size of 100 mm in length and 50 mm in width was cut out, and this was used as a measurement sample. In this measurement sample (sheet-shaped body), the absorption axis direction of the polarizing plate is parallel to the longitudinal direction. Referring to FIG. 5 , the measurement sample 1 is placed on the flat stage 2 with the pellicle facing upward (in such a way that the separator surface is in contact with the stage surface 2 ). In this state, the end of the measurement sample 1 is fixed to the flat table 2 at one short side of the measurement sample 1 . This fixation was performed by winding the tape 3 (repair tape manufactured by 3M Japan Co., Ltd.) at a position 10 mm from the end surface of the short side.

Next, from the short side opposite to the short side fixed with the tape 3, the protective film 4 of the measurement sample 1 is peeled at a speed of 20 m/min to the fixed position fixed with the tape 3, so that the tape 3 can be used. Starting from the fixed fixed position, the pellicle 4 is pulled up so that the pull-up angle of the pellicle 4 relative to the polarizing plate portion 1 ′ of the measurement sample 1 on the flat table 2 becomes 90°. In this state, the pulled-up pellicle 4 is in a state of tension without being loosened. The pull-up length of the protective film 4 is 90 mm. Release the protective film 4 after 5 seconds after the pull-up of the protective film 4 is completed, and measure the time until the protective film 4 sticks back to the polarizing plate part of the measurement sample on the flat platform 2 due to its own weight (from releasing the protective film 4 , until the end of the pellicle film 4 on the short side opposite to the short side fixed by the tape 3 touches the polarizing plate portion). The measurement of the fixation and return time of the sample 1 to the platform 2 was carried out in an environment with a temperature of 23° C. and a relative humidity of 50%.

(2) Measurement of peeling voltage

From the obtained polarizing plate with a pellicle (the state in which the separator was laminated on the outer surface of the first pressure-sensitive adhesive layer), a sheet-shaped body having a size of 100 mm in length and 50 mm in width was cut out, and this was used as a measurement sample. In this measurement sample (sheet-shaped body), the absorption axis direction of the polarizing plate is parallel to the longitudinal direction. Next, the separator laminated on the outer surface of the first adhesive layer was peeled off, and the measurement sample was bonded to a glass substrate (trade name "Eagle XG" manufactured by Corning Inc., 130 mm x 76.4 mm in width]. The glass substrate to which the measurement sample was bonded was autoclaved for 20 minutes at a temperature of 50° C. and a pressure of 5 kg/cm ² (490.3 kPa).

After the autoclave treatment, it was kept at a temperature of 23° C. and a relative humidity of 50% for 12 hours, and then placed in a printing tester (RK Print Coat Instruments Ltd., commercial product) under an atmosphere of a temperature of 23° C. and a relative humidity of 50%. name "K Printing Proofer"), peel the protective film from one short side of the measurement sample at a speed of 330mm/second in a 45° direction, and use an electrostatic measuring device (trade name "FMX-003" manufactured by SIMCO Corporation) to test the polarizing plate The surface (the surface to be attached to the pellicle. It is referred to as "the polarizing plate side" in Table 1.) and the surface of the pellicle (the surface to be attached to the polarizing plate. It is referred to as the "Pf side" in Table 1.) were measured separately The peeling voltage after 5 seconds from peeling. Table 1 shows the total values of the peeling voltage on the "polarizing plate side" and the peeling voltage on the "Pf side".

(3) Evaluation of air bubbles

Visually observe the measurement sample (polarizing plate with pellicle) after the stick-back time measurement in (1) above from the pellicle side, and evaluate the degree of air bubbles mixed between the polarizing plate and pellicle according to the following evaluation criteria Make an evaluation.

A: Bubbles do not exist at all,

B: Bubbles hardly exist,

C: There are many bubbles.

[Table 1]

Symbol Description

1 measurement sample; 1' the polarizing plate part of the measurement sample; 2 platform surface; 3 belt; 4 protective film; 10 polarizer; 21, 22 protective film; 50 brightness enhancement film; 60 protective film; 61 substrate film; 62 second adhesive layer; 70 release film; 100 polarizing plate.

Claims (6)

1. a kind of polarization plates with protecting film, have:Include the polarization plates of polarizing film;With a table for being laminated in the polarization plates The protecting film in face,

The patch of the protecting film time time is 17 seconds or more,

The time is pasted back about described, by the measurement of the vertical 100mm × horizontal 50mm sizes obtained from the polarization plates with protecting film The end of one short side of sample is fixed, from the opposite short side of the short side by the protection film stripping of the determination sample to The fixed position, thus obtains following states, by when discharging the protecting film by the state from the release to described Protecting film is pasted due to dead weight return to the polarization plates of the determination sample until timing definition be paste back the time, the state is Using the fixed position as starting point, the protecting film of determination sample described in pull-up so that the protecting film is relative to the measurement The pull-up angle of the polarization plates of sample becomes 90mm as the pull-up length of 90 °, the protecting film.

2. the polarization plates according to claim 1 with protecting film, by from determination sample short side with speed The release band voltage from stripping after 5 seconds on the surface of the polarization plates of determination sample when 330mm/ seconds stripping protecting films, described It is set as polarization plates side release band voltage, and by the stripping from stripping after 5 seconds on the surface of the protecting film of the determination sample From it is with voltage be set as protecting film side release band voltage when, the polarization plates side release band voltage and protecting film side stripping charge The aggregate value of pressure is in the range of -0.500~0.500kV, wherein the determination sample is from the polarization plates with protecting film The determination sample of the vertical 100mm × horizontal 50mm sizes obtained.

3. the polarization plates according to claim 1 or 2 with protecting film,

The polarization plates also include thermoplastic resin film, which is laminated in across adhesive layer or adhesive phase The polarizing film,

The protecting film is laminated in the surface of the thermoplastic resin film.

4. the polarization plates according to claim 1 or 2 with protecting film,

The polarization plates also include:Thermoplastic resin film is laminated in the polarizing film across adhesive layer or adhesive phase; And resin layer, it is laminated in the surface of the thermoplastic resin film,

The protecting film is laminated in the surface of the resin layer.

5. the polarization plates with protecting film according to any one of Claims 1 to 4, the protecting film include base material film, With the adhesive phase being laminated on the base material film.

6. a kind of optical laminate, it includes image-displaying member and the claim being laminated on the image-displaying member 1~ The polarization plates with protecting film described in any one of 5.