WO2016043242A1

WO2016043242A1 - Film laminate and polarization plate

Info

Publication number: WO2016043242A1
Application number: PCT/JP2015/076355
Authority: WO
Inventors: 将臣桑原; 雅康鈴木; 村田　力; 後藤　誠; 加藤　昌央; 亮村田
Original assignee: 株式会社巴川製紙所
Priority date: 2014-09-19
Filing date: 2015-09-16
Publication date: 2016-03-24
Also published as: JPWO2016043242A1

Abstract

[Problem] To provide a film laminate that has low moisture permeability by forming a low moisture-permeable layer on a cellulose film that has high moisture permeability. [Solution] This film laminate comprises a low moisture-permeable layer formed by repeating units that have a structure derived from a bifunctional urethane (meth)acrylate on a cellulose film. The repeating unit has a plurality of types of saturated cyclic aliphatic groups. Even if the moisture-permeable layer is thin, a polarization film to which the film laminate is adhered does not easily absorb moisture even in a high-temperature and high-humidity environment, and expansion and contraction of the polarization film is suppressed.

Description

Film laminate and polarizing plate

The present invention relates to a film laminate in which a low moisture-permeable layer is laminated, and a polarizing plate provided with the laminate on the film.

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

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

In order to improve these, in patent document 1, as a protective film of a polarizing plate, not a TAC film but an amorphous polyolefin resin film, a polyester resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin It is described that the moisture permeability of the protective film can be reduced by using a film, an alicyclic polyimide resin film, or the like.

JP 2004-245925 A

However, the amorphous polyolefin resin film, the polyester resin film, the acrylic resin film, the polycarbonate resin film, the polysulfone resin film, the alicyclic polyimide resin film, etc. have fewer polar groups than the TAC film. For this reason, even if surface modification such as plasma treatment, corona treatment, or saponification treatment is performed in order to improve the adhesion, it cannot be sufficiently adhered to the polarizing film using a hydrophilic adhesive. That is, there is a problem that bonding using a hydrophilic adhesive, which is widely performed as a general-purpose manufacturing method for polarizing plates, cannot be performed.

In view of the above problems, an object of the present invention is to provide a film laminate having low moisture permeability by providing a low moisture-permeable layer on a cellulose-based film that can be bonded with a hydrophilic adhesive. .

As a result of intensive studies on the above problems, the present inventors have provided a low moisture-permeable layer with a urethane (meth) acrylate monomer having a plurality of types of saturated cyclic aliphatic groups on a cellulose-based film. It has been found that a film laminate having a low thickness can be obtained.

The present invention includes the following forms.
<1> In a film laminate in which a low moisture-permeable layer is laminated on a cellulose-based film,
The low moisture-permeable layer is formed by a repeating unit having a structure derived from a bifunctional urethane (meth) acrylate,
The repeating unit has a plurality of types of saturated cycloaliphatic groups.
<2> The repeating unit is
The following structure A containing a saturated cycloaliphatic group R ¹ , and
The film laminate according to <1>, comprising the following structure C containing a saturated cycloaliphatic group R ³ .
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ³ —O— (Structure C)
<3> The repeating unit is
Further characterized in that it comprises the following structure B containing saturated aliphatic chain R ² film laminate according to <2>.
—O—R ² —CO— (Structure B)
<4> The film laminate according to <3>, wherein the repeating unit has a structure represented by the following general formula (1).

(In the general formula (1), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group; R ⁴ represents a hydrogen atom or a methyl group; R ⁵ represents a hydrogen atom, a methyl group or an ethyl group; m represents an integer of 1 to 4; An integer from 0 to 2 is shown, and the sum of r and s is 1 to 2, and x is an integer from 0 to 3)
<5> The film laminate according to <1> to <4>, wherein the cellulose-based film has a thickness of 10 to 80 μm and a moisture permeability of 300 g / (m ² · 24 hours) or more. body.
<6> The film laminate according to any one of <1> to <5>, wherein the moisture permeability is 150 g / (m ² · 24 hours) or less.
<7> A polarizing plate comprising the film laminate according to any one of <1> to <6> on at least one surface of a polarizing film.

Since the film laminate according to the present invention has a plurality of types of saturated cycloaliphatic groups in the low moisture permeable layer, even when the low moisture permeable layer is provided on a cellulose film having high moisture permeability, A film laminate having a low moisture permeability can be provided.

Hereinafter, the film laminate, the low moisture permeable layer, and the polarizing plate according to the present invention will be described, but the present invention is not construed as being limited to the following description.

<Film laminate>
The film laminate according to the present invention is
(1) On at least one side of the cellulosic film,
(2) In the film laminate in which the low moisture permeability layer is laminated,
The low moisture-permeable layer is formed by a repeating unit having a structure derived from a bifunctional urethane (meth) acrylate,
The repeating unit has a plurality of types of saturated cycloaliphatic groups. Hereafter, the structural member of a film laminated body is demonstrated.

<Cellulose film>
The cellulose film is preferably a colorless and transparent film composed of a cellulose resin. Examples of the cellulose resin include cellulose acetate, cellulose propionate, cellulose butyrate, and cellulose acetate propio. Examples thereof include a film composed of acrylate and cellulose acetate butyrate. From the viewpoint of adhesiveness with a polarizing film, a TAC film made of triacetyl cellulose as a raw material can be more preferably used. The thickness of the TAC film is not particularly limited, but since it can be easily processed even if it is thin, a thickness of 10 to 80 μm is generally suitably used. If the thickness is less than 10 μm, processing is difficult because it is too thin, and if the thickness exceeds 80 μm, it is not preferable because the demand for thinner liquid crystal displays in recent years cannot be met. Further, the moisture permeability of the TAC film is not particularly limited. However, in view of the problem of the present invention, the effect becomes more remarkable by providing the low moisture permeability layer on the film having a high moisture permeability. Is preferably 300 g / (m ² · 24 hours) or more.

<Low moisture permeability layer>
Since the low moisture permeable layer is a layer obtained by polymerizing a radiation curable composition derived from (meth) acrylate as described later, in other words, it can be said to be a radiation curable resin layer. The low moisture-permeable layer according to the present invention is formed by a repeating unit having a structure derived from a urethane (meth) acrylate that is a monomer, and the repeating unit has a plurality of types of saturated cycloaliphatic groups. That is, in the low moisture permeable layer, the matrix forming the polymer is formed of repeating units having a structure derived from urethane (meth) acrylate.

The low moisture-permeable layer according to the present invention is composed of at least the above repeating unit. When the basic aspect of the structure is roughly divided, (1) an aspect mainly including the above repeating unit, and (2) the above repeating unit is represented by block A. And a copolymer mainly with other block B is available. First, the basic configuration (1) will be described, and will be described in the order (2).

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

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

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

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

The main chain of the cyclic structure of the saturated cycloaliphatic group may be formed only by carbon atoms, or may be formed by oxygen atoms and / or nitrogen atoms in addition to carbon atoms. In addition, a linear and / or branched structure having 1 to 10 carbon atoms may be added to the carbon atom of the cyclic structure.

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

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

The 3-methylene-3,5,5-trimethylcyclohexane ring and the dimethylenetricyclodecane ring are preferable ring structures, and low moisture permeability is suitably exhibited in a low moisture-permeable layer containing the ring structure in a polymer chain. Is done.

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

An example of the linear structure is — (CH ₂ ) _n1 — (where n1 is an integer of 5 to 10), and — (CH ₂ ) ₅ — is particularly preferable. On the other hand, examples of the branched structure include structures in which hydrogen on at least one carbon of the linear structure is substituted with a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or the like.

As an example of the repeating unit, a structure including the following structure A including a saturated cycloaliphatic group R ¹ and a structure including the following structure C including a saturated cycloaliphatic group R ³ can be exemplified.
—CO—NH—R ¹ —NH—CO— (Structure A)
—O—R ³ —O— (Structure C)

The repeating unit, for example, diisocyanates containing R ^1, diols containing R ^3, and can be obtained from the urethane (meth) acrylate obtained by using a (meth) acrylate, it can be easily manufactured. As an example, the ratio of the structure A and the structure C can be m + 1: m or m: m + 1, where m is an integer of 1 to 4.

Further, the repeating units may further comprise the following structure B containing saturated aliphatic chain R ^2.
—O—R ² —CO— (Structure B)

The repeating unit is, for example, an isocyanate having a (meth) acrylate or (meth) acryl group in addition to a diisocyanate containing R ¹ , an ester containing R ² (optionally used), a diol containing R ³ And can be easily manufactured. As an example, the ratio of the structure A, the structure B, and the structure C can be m + 1: m (r + s): m, m + 1: k + n: m, m: m (r + s): m + 1, m: k + n: m + 1. . M represents an integer of 1 to 4, r and s each represents an integer of 0 to 2, and the sum of r and s is 1 to 2, k represents an integer of 0 to 2, n Represents an integer of 0-2.

Specific examples of the repeating unit having the saturated cycloaliphatic group and saturated aliphatic chain described above are shown below. As shown in the general formula (1), the structure derived from (meth) acrylate is a (meth) acrylate structure H ₂ C═CH—CO ₂ — (or H ₂ C═C (CH ₃ ) —CO ₂ —. ) In which a carbon-carbon double bond is cleaved to form a single bond.

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

When the m in the general formula (1) is an integer of 1 to 4, the moisture permeability of the low moisture permeable layer can be further reduced. m is more preferably 1 or 2, and even more preferably 1. The same applies to general formulas (2), (3), and (4) described later.

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

Other specific examples of the repeating unit are shown below.

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

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

Other specific examples of the repeating unit are shown below.

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

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

Other specific examples of the repeating unit are shown below.

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

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

In addition, the isomer of the structure represented by the general formula (1a), the general formula (2a), the general formula (3a), and the general formula (4a) is also included in the repeating unit according to the present invention. Furthermore, the repeating unit is not necessarily determined to be one structure. That is, for example, in the adjacent repeating unit of the general formula (1), even if one m is 1, the other m is not limited to 1, and may be any one of 1 to 4. The same applies to r, s, x, k, n, y, z, and p in other general formulas.

Next, the mode related to the copolymer in the low moisture-permeable layer of the present invention will be described. The low moisture-permeable layer according to the present embodiment contains the above repeating unit as the block A and the block B including a structure derived from a bifunctional (meth) acrylate having one kind of saturated cycloaliphatic group. It is comprised by the made copolymer. In other words, the low moisture-permeable layer according to the copolymer comprises a block A (repeating unit) comprising a bifunctional urethane (meth) acrylate monomer unit having a plurality of types of saturated cycloaliphatic groups, and 1 It can be said that it comprises a copolymer containing a block B containing a bifunctional (meth) acrylate monomer unit having a kind of saturated cycloaliphatic group.

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

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

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

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

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

The dimethylene tricyclodecane ring is a preferred ring structure, and low moisture permeability is suitably expressed in a low moisture permeability layer containing the ring structure in a polymer chain.

Specific examples of the block B having the saturated cycloaliphatic group and the saturated aliphatic chain described above are shown below. Block B has a structure derived from (meth) acrylate at both ends, and the structure derived from (meth) acrylate is bonded to another block B or to block A (-block B-block B-, Or -Block B-Block A-). As shown in the general formula (5), the acrylate-derived site is a structure in which the carbon-carbon double bond of the acrylate structure H ₂ C═HC—CO ₂ — is cleaved to form a single bond (methacrylate). The structure is the same).

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

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

The mass ratio of the block A to the block B in the copolymer is not particularly limited, but in order to make the degree of moisture permeability reduction of the low moisture permeable layer due to the block B suitable, the block A: block B = 70. : 30 to 15:85 is preferable, 60:40 to 15:85 is more preferable, and 50:50 to 15:85 is particularly preferable.

Further, the proportion of the copolymer in the low moisture-permeable layer according to the present invention is preferably high from the viewpoint of reducing the moisture permeability of the low-moisture permeable layer, and is 70% by mass or more based on the total mass of the low moisture-permeable layer. 99.5% by mass or less, more preferably 80% by mass or more and 99.5% by mass or less.

The structure of the polymer chain (repeating unit (block A), block B) of the low moisture-permeable layer according to the present invention is determined by pyrolysis GC-MS and FT-IR. Can be determined by analyzing the above. In particular, pyrolysis GC-MS is useful because it can detect monomer units contained in the low moisture-permeable layer as monomer components.

The low moisture-permeable layer may contain various additives such as an ultraviolet absorber, a leveling agent, and an antistatic agent as long as the film-forming property of the low moisture-permeable layer and the low moisture permeability are not impaired. Thereby, it is possible to give an ultraviolet absorption characteristic, surface smoothness, and an antistatic characteristic to a low moisture-permeable layer.

Furthermore, the low moisture permeability layer may contain a thiol material. Thereby, it is possible to provide toughness to a low moisture-permeable layer.

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

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

The low moisture permeability layer according to the present invention is a layer having a low moisture permeability, and is preferably 150 g / (m ² · 24 hours) or less in a 30 μm thin layer (thickness of 30 μm or less), more It is preferably 120 g / (m ² · 24 hours) or less, and particularly preferably 100 g / (m ² · 24 hours) or less. Although the lower limit of moisture permeability is not particularly limited, it is, for example, 15 g / (m ² · 24 o'clock) or more. In addition, it is preferable that the water vapor transmission rate as a film laminated body satisfy | fills the same value.

<Functional layer>
The film laminate according to the present invention, on the low moisture permeable layer,
(1) A hard coat layer having scratch resistance,
(2) an antiglare layer that scatters light, and
(3) You may provide either the antireflective layer comprised by the high refractive index layer provided on the said low moisture-permeable layer, and the low refractive index layer provided in the said high refractive index layer. Hereinafter, (1) to (3) will be described. In addition, you may provide a well-known other layer in the range which does not inhibit the effect of this invention.

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

As the resin component constituting the hard coat layer, radiation curable resin is suitable because it can be efficiently cured by a simple processing operation, and radiation that gives a film having sufficient strength and transparency after curing. A curable resin can be used without particular limitation.

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

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

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

In order to impart functions other than hard coat properties, various additives can be added to the hard coat layer. For example, fluorine or silicone leveling agents added to improve the smoothness of the coated surface, and electron conjugated, metal oxide or ionic antistatic agents added to prevent dust adhesion. An agent or the like may be appropriately selected and used depending on the required function. The point which can use an additive agent is the same also about the following glare-proof layer and a low refractive index layer.

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

Although there is no particular limitation on the method for forming irregularities on the surface of the antiglare layer, it is easy to control the shape of the irregularities by applying a radiation curable resin containing translucent fine particles and curing after application. preferable.

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

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

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

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

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

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

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

"Polarizer"
Next, the polarizing plate of the present invention will be described. The polarizing plate which concerns on this invention equips the at least single side | surface of a polarizing film with the said film laminated body.

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

A hydrophilic adhesive is preferably used for laminating the polarizing film and the cellulose-based film of the film laminate, but is not limited thereto. As long as the hydrophilic adhesive is supplied in a liquid-applicable state, a known adhesive conventionally used in the production of polarizing plates can be used. From the viewpoint of weather resistance and polymerizability, PVA can be used. Those containing a resin are preferred.

The polarizing plate according to the present invention includes the above-described film laminate on at least one surface, and includes a configuration in which the film laminate is provided on both surfaces of the polarizing plate. Since the film laminate has a low moisture permeability even if it is a thin layer, the polarizing film is difficult to absorb moisture even under a high temperature and high humidity environment, and the expansion and contraction of the polarizing film is suppressed.

<< Method for producing film laminate >>
Although the manufacturing method of the film laminated body which concerns on this invention will not be specifically limited if the said film laminated body can be manufactured, The method including the film laminated body formation process containing the following processes (A1) and (A2) as an example is mentioned. .
Step (A1): A radiation curable composition is applied on a cellulosic film.
Step (A2): After coating, the radiation curable composition is cured to form a film laminate.

The radiation curable composition contains urethane (meth) acrylate as an essential component. The urethane (meth) acrylate, which is a monomer, is a raw material for the low moisture-permeable layer, and the monomer is polymerized to form the repeating unit described in <Low moisture-permeable layer>.

In another embodiment, the radiation curable composition includes a urethane (meth) acrylate that generates the repeating unit (block A) and a (meth) acrylate that generates the block B as a raw material for the low moisture-permeable layer. By copolymerizing these monomers, the copolymer described in the above <low moisture permeable layer> is formed.

Furthermore, in another embodiment, the radiation curable composition contains (meth) acrylate that generates block B in addition to urethane (meth) acrylate that generates the repeating unit (block A). Urethane (meth) acrylates are polymerized, or urethane (meth) acrylate and (meth) acrylate are copolymerized to form a polymer chain, thereby forming the polymer chain described in <Low moisture permeability layer> above. A low moisture permeable layer is formed.

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

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

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

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

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

Specifically, when a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (1) described above is exemplified, [1] an ester having R ² and a diol having R ³ are represented by m ( r + s): m is reacted at a molar ratio, and further m + 1 mole of diisocyanate having R ¹ is reacted to obtain an intermediate having —N═C═O groups at both ends. [2] Thereafter, urethane (meth) acrylate represented by the following general formula (6) is obtained by reacting 1 mol of the intermediate with 2 mol of (meth) acrylate.

(In the general formula (6), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group; R ⁴ represents a hydrogen atom or a methyl group; R ⁵ represents a hydrogen atom, a methyl group or an ethyl group; m represents an integer of 1 to 4; An integer from 0 to 2 is shown, and the sum of r and s is 1 to 2, and x is an integer from 0 to 3)

An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (2) is as follows: [1] A diisocyanate having R ¹ and a diol having R ³ are reacted at a molar ratio of m + 1: m. Thus, an intermediate having —N═C═O groups at both ends is obtained. [2-1] Thereafter, 2 mol of (meth) acrylate is reacted with 1 mol of the above intermediate, or [2-2] k + n mol of R ² is added with respect to 1 mol of the above intermediate. Obtained by reacting 2 moles of (meth) acrylate, or [2-3] reacting 2 moles of (meth) acrylate with an ester having k + n moles of R ^2. The urethane (meth) acrylate corresponding to the repeating unit represented by the general formula (7) can be obtained by any method in which (meth) acrylate is reacted with 1 mol of the above intermediate.

(In General Formula (7), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and R ⁴ represents a different saturated cycloaliphatic group, R ⁴ represents a hydrogen atom or a methyl group, R ⁵ represents a hydrogen atom, a methyl group or an ethyl group, m represents an integer of 1 to 4, and k represents 0 to 2 N represents an integer from 0 to 2, and x represents an integer from 0 to 3)

An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (3) is as follows: [1] A diisocyanate having R ¹ and an ester having R ² are converted into m: m (r + s) moles. The reaction is carried out in a ratio, and further m + 1 mol of diol having R ³ is reacted to obtain an intermediate having hydroxyl groups at both ends. [2] Thereafter, urethane (meth) acrylate corresponding to the repeating unit represented by the general formula (8) is obtained by reacting 2 mol of an isocyanate having a (meth) acryl group with 1 mol of an intermediate. Is obtained.

(In the general formula (8), R ¹ represents a saturated cycloaliphatic group, R ² represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R ³ represents R ¹ and Each represents a different saturated cycloaliphatic group; R ⁴ represents a hydrogen atom or a methyl group; R ⁵ represents a hydrogen atom, a methyl group or an ethyl group; m represents an integer of 1 to 4; An integer from 0 to 2 is shown, and the sum of r and s is 1 to 2, and x is an integer from 0 to 3)

An example of a method for synthesizing a urethane (meth) acrylate corresponding to the repeating unit of the general formula (4) is as follows: [1] A diisocyanate having R ¹ and a diol having R ³ are reacted at a molar ratio of m: m + 1. Thus, an intermediate having hydroxyl groups at both ends is obtained. [2-1] Then, 2 mol of an isocyanate having a (meth) acryl group is reacted with 1 mol of the intermediate, or [2-2] k + n mol with respect to 1 mol of the intermediate. After reacting the ester having R ² , react with an isocyanate having 2 mol of a (meth) acryl group, or [2-3] k + n mol with respect to an isocyanate having 2 mol of a (meth) acryl group. The urethane (meth) acryl acrylate obtained by reacting the ester having R ² is reacted with 1 mol of the above intermediate, and the repeating unit represented by the general formula (9) is produced by any method. The corresponding urethane (meth) acrylate is obtained.

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

The structure of a typical monomer that gives rise to block B is shown below.

(In the general formula (10), R ⁶ represents a saturated cycloaliphatic group, R ⁷ represents a hydrogen atom or a methyl group, and y and z are integers of 0 to 2)

Preparation of the radiation curable composition is performed by adding a photopolymerization initiator that initiates polymerization of the monomer to the monomer that generates the repeating unit. In another embodiment, the radiation curable composition is prepared by adding a photopolymerization initiator to the monomer that generates the block B in addition to the monomer that generates the repeating unit (block A).

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

Various additives and thiol-based materials such as the ultraviolet absorber, leveling agent and antistatic agent described above in <Low moisture permeable layer> may be added to the radiation curable composition.

In the radiation curable composition, each ratio of the monomer (the total amount of the monomer that generates the repeating unit (block A) and the monomer that generates the block B), the photopolymerization initiator, and any of the various additives depends on the type of each material. However, it is difficult to define uniquely, but as an example, the total amount of monomers is 50% by mass or more and 99% by mass or less, the photopolymerization initiator is 0.5% by mass or more and 10% by mass or less, various additions An agent can be 0.01 mass% or more and 50 mass% or less. Further, an organic solvent such as toluene may be added to the radiation curable composition.

The mass ratio of the monomer A that generates the block A and the monomer B that generates the block B is such that the lowering of the moisture permeability of the low moisture permeable layer due to the block B is suitable. = 70: 30 to 15:85 is preferable, 60:40 to 15:85 is more preferable, and 50:40 to 15:85 is particularly preferable.

In order to apply the prepared radiation curable composition on the cellulose film, it is preferable to use a coating method such as a roll coating method or a gravure coating method in consideration of continuous productivity. By the coating method, the radiation curable composition can be applied so as to form a thin layer, for example, a low moisture permeability layer of 50 μm or less, preferably 30 μm or less.

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

By curing the radiation curable composition, a low moisture-permeable layer is formed on the cellulose film, and a film laminate in which the low moisture-permeable layer is laminated on the cellulose film is obtained.

[Functional layer formation process]
As a variation of the manufacturing method of a film laminated body, the manufacturing method which contains a functional layer formation process (B) after a film laminated body formation process (A1) and (A2) is mentioned. In the functional layer formation step (B), the radiation curable composition that is the raw material of the functional layer described above in << functional layer >> is applied on the film laminate and cured to form the functional layer on the film laminate. To do.

The functional layer is not particularly limited, and examples thereof include the hard coat layer, the antiglare layer, and the antireflection layer described above. The radiation curable composition that is a raw material of the functional layer includes the resin described above in the description of the hard coat layer, the antiglare layer, and the antireflection layer. An organic solvent such as methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone (MIBK), isopropyl alcohol (IPA), or toluene may be added.

In order to apply the radiation curable composition, which is a raw material of the functional layer, on the film laminate, it is preferable to use a coating method such as a roll coating method or a gravure coating method in consideration of continuous productivity. According to the radiation curable composition to be used, a method of arbitrarily heating and then crosslinking and curing by ultraviolet irradiation or the like may be used.

In order to form the antiglare layer on the film laminate, for example, it can be suitably obtained by applying a radiation curable composition containing translucent fine particles on the film laminate. The antiglare layer thus obtained has an antiglare function for scattering light because the surface has irregularities. The shape of the unevenness is determined by the required antiglare property, and a more preferable uneven shape can be defined by the roughness parameter Ra, Ra: 0.01 μm or more, Sm: 50 μm to 500 μm, average slope Angle: More preferably from 0.1 ° to 3.0 °.

When forming the functional layer, a plurality of layers can be formed. For example, when a plurality of hard coat layers are formed, a first hard coat layer is formed on the film laminate, and a second hard coat layer is formed on the first hard coat layer. An antiglare layer may be formed in place of the second hard coat layer.

Further, when forming the antireflection layer, a high refractive index layer is formed on the film laminate, and a low refractive index layer is formed on the high refractive index layer. Thereby, the film laminated body laminated | stacked in order of the film laminated body and the antireflection layer is obtained.

The method for producing a film laminate according to the present invention is not limited to the method described above, and may be formed by the following method. That is, (1) a method of forming a low moisture-permeable layer on a release film, transferring the low moisture-permeable layer to a TAC film, and then removing the release film, (2) forming a functional layer on the release film, After forming a low moisture permeable layer and transferring the low moisture permeable layer to the TAC film, (3) After forming the low moisture permeable layer on the peeled film and forming the functional layer thereon The method of bonding the surface which peeled the peeling film to the TAC film is mentioned.

<< Polarizing plate manufacturing method >>
The polarizing plate according to the present invention includes the film laminate according to the present invention on at least one surface of a polarizing film. In the manufacturing method of the polarizing plate which concerns on this invention, the point which bonds the said film laminated body to a polarizing film is important, What is necessary is just to employ | adopt a well-known method as a bonding method, and it is not specifically limited.

For example, after the film laminate forming step, or after the film laminate forming step and the functional layer forming step, if the cellulose film side of the film laminate is bonded to a polarizing film, the polarizing plate according to the present invention is obtained. can get.

The process related to the method for producing a polarizing plate will be described more specifically. The following steps (C1) to (C3) are performed after the film laminate forming step or after the film laminate forming step and the functional layer forming step.

(C1) a coating step of applying a hydrophilic adhesive to the cellulose-based film side (or polarizing film) of the film laminate,
(C2) A bonding step in which a polarizing film (or a cellulose-based film side of the film laminate) is applied to the hydrophilic adhesive surface applied in the coating step and pressed.
(C3) A curing step in which the hydrophilic adhesive is cured by heating and drying with a dryer on the film laminate in which the film laminate is bonded to the polarizing film via the hydrophilic adhesive.

In the coating step (C1), a hydrophilic adhesive is applied to the cellulose-based film side of the film laminate, which becomes the bonding surface of the polarizing film (or instead of the cellulose-based film side of the film laminate, polarized light is applied). Apply a hydrophilic adhesive to the film). As a coating machine used here, a well-known thing can be used suitably, for example, the coating machine using a gravure roll etc. are mentioned. At this time, in order to improve the adhesiveness between the cellulose-based film and the hydrophilic adhesive, the cellulose-based film surface may be appropriately subjected to surface treatment such as plasma treatment, corona treatment, and saponification treatment in advance. The saponification treatment is performed by immersing the film in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

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

In the curing step (C3), after the film laminate is bonded to the polarizing film, the solvent is volatilized and the hydrophilic adhesive is cured by heating and drying with a dryer.

In the above description, the polarizing film is bonded to the cellulose-based film side of the film laminate. However, as a modification, the cellulose-based film used in the << film laminate manufacturing method >> has a polarizing film bonded in advance. It may be used. In this case, a low moisture-permeable layer is formed on the cellulose film with a polarizing film. Thereby, the polarizing plate which concerns on this invention is obtained.

Hereinafter, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the contents of the examples. The obtained film laminate was measured, and the moisture permeability of the film laminate was measured by the following measurement method.

[Film thickness]
Using a digital linear gauge D-10HS and a digital counter C-7HS (manufactured by Ozaki Mfg. Co., Ltd.), the film thickness of the cellulose film and the film laminate is measured, and the film thickness of the cellulose film is determined from the film laminate thickness. The film thickness of the low moisture-permeable layer was obtained.

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

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

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

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

Charge 44.58 g (2 mol) of isophorone diisocyanate to the flask, add 196.29 g (1 mol) of tricyclodecane dimethanol at a reaction temperature of 70 ° C., and ε-caprolactone-modified hydroxyethyl when the residual isocyanate group becomes 5.7%. Acrylate (2) 2 mol 460.52 g was added, and the reaction was continued until the residual isocyanate group became 0.1% to obtain urethane acrylate (compound 2) which is a monomer for generating repeating units. Compound 2 is a raw material for the low moisture-permeable layer formed by the repeating unit in which m is 1 in the general formula (2a).

[Production Example 3]
Compound 1a, which is a monomer that produces repeating units, is obtained in the same manner as in Production Example 1 except that the amount of diol (1) synthesized is changed to twice and the amount of isophorone diisocyanate used is changed from 2 mol to 3 mol. It was. Compound 1a is a raw material for the low moisture-permeable layer formed by the repeating unit in which m is 2 in the general formula (1a).

[Production Example 4]
Compound 1b was obtained in the same manner as in Production Example 1, except that the amount of diol (1) synthesized was changed to 3 times and the amount of isophorone diisocyanate used was changed from 2 mol to 4 mol. Compound 1b is a raw material for the low moisture-permeable layer formed by the repeating unit having m of 3 in the general formula (1a).

[Example 1: TAC film substrate / low moisture-permeable layer]
The following radiation curable composition for forming a low moisture permeable layer (P1) was applied to a TAC film KC2UAW (25 μm thickness, moisture permeability 1060 g / (m ² · 24 h)) manufactured by Konica Minolta using an applicator. The radiation curable composition (P1) for forming a low moisture permeable layer contains toluene and has a solid content (NV) of 60%.

The coating thickness of the radiation curable composition (P1) for forming a low moisture permeable layer was adjusted so that the film thickness after drying was 20 μm to 30 μm. The coating film is dried in a clean oven set at a drying oven temperature of 100 ° C, and then UV-cured under a nitrogen atmosphere under conditions of peak illuminance of 326 mW / cm ² and integrated light intensity of 192 mJ / cm ² , A film laminate having a low moisture permeability layer formed on one side was obtained. The evaluation results for this film laminate are shown in Table 6.

[Example 2: TAC film substrate / low moisture permeability layer / HC layer]
The following radiation curable composition for HC layer formation (HC1) was applied to the low moisture permeable layer side of the film laminate obtained in Example 1 by a reverse coating method. The formed coating film is dried at 100 ° C. for 1 minute, and then irradiated with ultraviolet rays using a 120W / cm condensing high-pressure mercury lamp in a nitrogen atmosphere (irradiation distance 10 cm, irradiation time 30 seconds). The film was cured to form a hard coat layer (HC layer) having a thickness of 2.5 μm and a refractive index of 1.52. The evaluation results for this film laminate are shown in Table 6.

[Example 3: TAC film substrate / low moisture-permeable layer / AG layer (containing filler)]
The following radiation curable composition for AG layer formation (AG1) was applied to the low moisture-permeable layer side of the film laminate obtained in Example 1 by a reverse coating method. The formed coating film is dried at 100 ° C. for 1 minute, and then irradiated with ultraviolet rays using a 120W / cm condensing high-pressure mercury lamp in a nitrogen atmosphere (irradiation distance 10 cm, irradiation time 30 seconds). The film was cured to form an antiglare layer (AG layer) having a thickness of 6 μm. The evaluation results for this film laminate are shown in Table 6.

[Example 4: TAC film substrate / low moisture permeability layer / high refractive index layer / AG layer / low refractive index layer]
The following low refractive index paint (LR1) was applied to the AG layer side of the film laminate obtained in Example 3 by a reverse coating method, and the coating film was dried at 100 ° C. for 1 minute to obtain a thickness of 0.1 μm, An uneven low refractive index layer having a refractive index of 1.38 was formed. Then, it left still at 60 degreeC for 120 hours for hardening of a low refractive index layer. The evaluation results for this film laminate are shown in Table 6.

[Example 5: TAC film substrate / low moisture permeability layer / high refractive index layer / HC layer / low refractive index layer]
The following radiation curable composition for forming a high refractive index layer and HC layer (HC2) was applied to the low moisture permeable layer side of the film laminate obtained in Example 1 by a reverse coating method. After drying at 100 ° C for 1 minute, UV irradiation (irradiation distance 10cm, irradiation time 30 seconds) is performed with one 120W / cm condensing type high-pressure mercury lamp in nitrogen atmosphere, the coating film is cured, and the thickness is 2.5μm. An HC layer having a refractive index of 1.64 was formed.

Subsequently, using the applicator, the low refractive index paint (LR1) described in Example 4 was applied onto the high refractive index layer, and the coating film was dried at 100 ° C. for 1 minute, and then cured to be thick. A low refractive index layer having a thickness of 0.1 μm and a refractive index of 1.38 was formed. Then, it left still at 60 degreeC for 120 hours for hardening of a low refractive index layer. The evaluation results for this film laminate are shown in Table 6.

[Examples 6 to 8: TAC film substrate / low moisture-permeable layer]
In Example 6, Compound 1 was changed to Compound 2, in Example 7, Compound 1 was changed to Compound 1a, and in Example 8, Compound 1 was changed to Compound 1b. A film laminate in which a low moisture-permeable layer was formed on one side of the TAC film was obtained. The evaluation results for this film laminate are shown in Table 6.

[Comparative Example 1]
A cured film was formed on one side of the TAC film in the same manner as in Example 1 except that Compound 1 was changed to Compound 3 (manufactured by Arkema) represented by the following general formula (11) to obtain a film laminate. The evaluation results for this film laminate are shown in Table 6.

As shown in Table 6, when the compounds 1 of Examples 1 to 5 and the compound 2 of Example 6 were used, a film laminate having a very low moisture permeability was obtained. In Examples 2 to 5, the moisture permeability was lower due to the functional layer. Although the film laminated body which uses the compound 1a, 1b in Example 7 and 8 as a raw material is inferior to Example 1 (compound 1), the low water vapor transmission required for the film laminated body of the present invention was achieved.

On the other hand, the film laminate formed in Comparative Example 1 had very high moisture permeability. Since the repeating unit of Compound 3 does not contain a urethane bond (—NH—CO—O—) or a saturated cycloaliphatic group, the cohesive force between the repeating units becomes excessively low, thereby increasing the water vapor permeability. It is thought.

The film laminate according to the present invention has a low moisture permeability in a thin layer state, and is useful as a constituent member of a polarizing plate, particularly in applications where low moisture permeability is required, and can be used in various fields. .

Claims

In a film laminate in which a low moisture-permeable layer is laminated on a cellulose film,
The low moisture-permeable layer is formed by a repeating unit having a structure derived from a bifunctional urethane (meth) acrylate,
The repeating unit has a plurality of types of saturated cycloaliphatic groups.
The above repeating unit is
The following structure A containing a saturated cycloaliphatic group R 1 , and
Film laminate according to claim 1, characterized in that it comprises the following structure C that includes a saturated cyclic aliphatic group R 3.
—CO—NH—R 1 —NH—CO— (Structure A)
—O—R 3 —O— (Structure C)
The above repeating unit is
The film laminate according to claim 2, further comprising the following structure B containing a saturated aliphatic chain R 2 .
—O—R 2 —CO— (Structure B)
The said laminated unit is a structure represented by following General formula (1), The film laminated body of Claim 3 characterized by the above-mentioned.

(In the general formula (1), R 1 represents a saturated cycloaliphatic group, R 2 represents a saturated aliphatic chain having a linear or branched structure having 5 to 10 carbon atoms, and R 3 represents R 1 and Each represents a different saturated cycloaliphatic group; R 4 represents a hydrogen atom or a methyl group; R 5 represents a hydrogen atom, a methyl group or an ethyl group; m represents an integer of 1 to 4; An integer from 0 to 2 is shown, and the sum of r and s is 1 to 2, and x is an integer from 0 to 3)
The film lamination according to any one of claims 1 to 4, wherein the cellulose-based film has a thickness of 10 to 80 µm and a moisture permeability of 300 g / (m 2 · 24 hours) or more. body.
The film laminate according to any one of claims 1 to 5, wherein the moisture permeability is 150 g / (m 2 · 24 hours) or less.
A polarizing plate comprising the film laminate according to any one of claims 1 to 6 on at least one surface of a polarizing film.