JP5105065B2 - Method for producing polarizing plate with retardation film - Google Patents

Description

  The present invention relates to a method for producing a polarizing plate with a retardation film useful for producing an image display device such as a liquid crystal panel.

Conventionally, in a laminating method in which a thin-layer adherend such as a plastic film or sheet or a thin-layer adherend such as a plastic film or sheet is bonded to a thin-layer adherend made of another material, ethylene is used. -A solvent-type adhesive composition containing a vinyl acetate copolymer or a polyurethane polymer is applied to the first thin layer adherend and dried, and then the second thin layer adherend is attached to the nip- A dry laminating method in which pressure bonding is performed with a roller or the like is mainly performed.
The adhesive composition used in this method generally contains a large amount of a solvent in order to make the coating amount of the composition uniform, but for this reason, a large amount of solvent vapor is volatilized during drying, resulting in toxicity, work safety and Environmental pollution is a problem.
As an adhesive composition for solving these problems, a solventless adhesive composition has been studied.

As the solventless adhesive composition, a two-component adhesive composition and an adhesive composition that is cured by an active energy ray such as an ultraviolet ray or an electron beam are widely used.
As the two-component adhesive composition, a so-called polyurethane adhesive composition is mainly used in which a polymer having a hydroxyl group at the terminal is a main agent and a polyisocyanate compound having an isocyanate group at the terminal is a curing agent. However, the composition has the disadvantage that it takes too long to cure.
On the other hand, the active energy ray-curable adhesive composition is excellent in productivity because of its high curing rate, and has recently attracted attention.

On the other hand, thin display devices such as liquid crystal display devices have been widely used as display elements for televisions, portable personal computers, mobile phones, word processors and the like as well as simple display devices in digital watches and various electric appliances. In recent years, an active energy ray-curable adhesive has been used for bonding various optical films used in the liquid crystal display element.
The adhesive composition used in the optical film is required to have a performance capable of maintaining the adhesive force under severe conditions under high temperature and high humidity conditions. However, most of the conventional active energy ray-curable adhesive compositions are excellent in initial adhesive strength, but if they are used for a long time under high temperature or high humidity conditions, the adhesive strength decreases and causes peeling. Or whitening due to moisture absorption.

The present inventors have proposed an adhesive (Patent Document 1) that contains a polymer having a glass transition temperature of 40 ° C. or higher in the composition so far, or by using a compound having an imide group. The adhesive (patent document 2) which is excellent in the adhesiveness under humidity is proposed.
Further, the present inventors have proposed an adhesive between a polymethyl methacrylate (PMMA) plate and a film, but when used as a laminate adhesive between films, the adhesive strength is insufficient. (Patent Document 3).

JP 2000-072833 A (Claims) JP 2001-064594 A (Claims) JP 2005-272775 A (Claims)

In recent years, polarizing plates used in liquid crystal panels and the like are also required to be used under severe conditions such as higher temperatures and higher humidity, used outdoors under sunlight, and have a longer product life. Thus, the conventionally proposed adhesives have become unsatisfactory due to problems such as a decrease in adhesive strength and coloring over time.
The present inventors have intensively studied in order to find a polarizing plate with a retardation film that is excellent in adhesive strength under both high temperature and high humidity conditions and is less colored even when used for a long time.

  As a result of various studies, the present inventors have developed a polarizing film with a retardation film produced using an adhesive composition comprising a urethane (meth) acrylate having a specific structure, a phenol compound having a specific structure, and a sulfur-based antioxidant. It was found that the plate was excellent in adhesive strength under both high temperature and high humidity conditions, with little coloration, and was at a practical level, and the present invention was completed.

  According to the polarizing plate with a retardation film of the present invention, excellent adhesive force can be maintained under any condition of high temperature or high humidity, and coloration with time is small.

The present invention relates to a method for producing a polarizing plate with a retardation film (hereinafter, simply referred to as a polarizing plate) comprising the following steps [1] to [3].
[1] A step of applying the following active energy ray-curable adhesive composition to a polarizing film or a retardation film
[2] A step of bonding the retardation film or the polarizing film to the polarizing film or the retardation film coated with the composition, respectively.
[3] A process of irradiating active energy rays from the surface of any of the substrates after bonding any of the films ○ Active energy ray-curable adhesive composition: including the following components (A) to (D) An active energy ray-curable adhesive composition.
(A) Urethane (meth) acrylate having a polyester skeleton or a polycarbonate skeleton (B) A phenol compound having at least one group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group. (C) Sulfur antioxidant which is a diester type thioether compound represented by the following formula (6) and / or a tetraester type thiocarbonate compound represented by the following formula (7) (D) Other than the component (A) Hereinafter, an active energy ray-curable adhesive composition, a polarizing film, and a retardation film will be described.
In the present specification, acrylate and / or methacrylate is represented by (meth) acrylate, acryloyl group and / or methacryloyl group is represented by (meth) acryloyl group, and acrylic acid and / or methacrylic acid is represented by (meth) acrylic acid. .

1. Active energy ray-curable adhesive composition The active energy ray-curable adhesive composition used in the present invention is (A) urethane (meth) acrylate having a polyester skeleton or a polycarbonate skeleton (hereinafter referred to as component (A)), (B) a phenol compound having at least one group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group [hereinafter referred to as component (B)], (C) Sulfur-based antioxidants [hereinafter referred to as component (C)] and (D ) which are diester thioether compounds represented by the following formula (6) and / or tetraester thiocarbonate compounds represented by the following formula (7) ) A compound having an ethylenically unsaturated group other than the component (A) [hereinafter referred to as component (D)].
Hereinafter, each component will be described.
In addition, as (A)-(D) component, each compound mentioned later can be used individually or in combination of 2 or more types.

1-1. (A) Component The component (A) is a urethane (meth) acrylate having a polyester skeleton or a polycarbonate skeleton. In this invention, by containing (A) component, the hardened | cured material obtained will be excellent in adhesive force in any conditions of high temperature or high humidity.
On the other hand, in the composition containing urethane (meth) acrylate having a skeleton other than the polyester skeleton or the polycarbonate skeleton different from the component (A), the adhesive strength under high temperature conditions and high humidity conditions of the resulting cured product is reduced. End up.
As the component (A), both oligomers and polymers can be used, and those having a weight average molecular weight of 500 to 50,000 are preferable, and those having a weight average molecular weight of 3,000 to 40,000 are more preferable.
In the present invention, the weight average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography into polystyrene.

As the component (A), various compounds can be used, and examples thereof include compounds obtained by reacting a hydroxyl group-containing (meth) acrylate with a polyol having a polyester skeleton or a polycarbonate skeleton and an organic polyisocyanate reaction product.
The component (A) is preferably a urethane (meth) acrylate having two (meth) acryloyl groups (hereinafter referred to as a bifunctional urethane (meth) acrylate), and a diol having a polyester skeleton or a polycarbonate skeleton. More preferred is a bifunctional urethane (meth) acrylate obtained by reacting a hydroxyl group-containing (meth) acrylate with a reaction product of an organic diisocyanate.

Here, examples of the polyol having a polyester skeleton include an esterification reaction product of a diol such as a low molecular weight diol or polycaprolactone diol and an acid component such as a dibasic acid or an anhydride thereof.
Examples of the low molecular weight diol include ethylene glycol, propylene glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol.
Examples of the dibasic acid or an anhydride thereof include adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and terephthalic acid, and anhydrides thereof.
Examples of the polycarbonate polyol include a reaction product of the low molecular weight diol or / and bisphenol such as bisphenol A and a carbonic acid dialkyl ester such as ethylene carbonate and carbonic acid dibutyl ester.

  Organic polyisocyanates include tolylene diisocyanate, 1,6-hexane diisocyanate, 4,4′-diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, 1,6-hexane diisocyanate trimer, hydrogenated tolylene diisocyanate, hydrogenated 4 , 4'-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, paraphenylene diisocyanate, tolylene diisocyanate dimer, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate interadduct, 4,4'-dicyclohexylmethane diisocyanate , Trimethylolpropane tris (tolylene diisocyanate) adduct, isophorone diisocyanate and the like. The organic polyisocyanate is preferably an organic diisocyanate.

  As the hydroxyl group-containing (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxy Examples include octyl (meth) acrylate, pentaerythritol tri, di or mono (meth) acrylate, and hydroxyalkyl (meth) acrylate such as trimethylolpropane di or mono (meth) acrylate.

  These can be obtained by heating and stirring the organic isocyanate and polyol component to be used in the presence of an addition catalyst such as dibutyltin dilaurate, adding hydroxyalkyl (meth) acrylate, heating and stirring, and adding reaction.

  As the component (A), urethane acrylates using non-aromatic polyester polyols and polycarbonate polyols are preferable in that the adhesive strength under high humidity is particularly excellent and the cured adhesive is less colored over time. .

1-2. Component (B) The component (B) is a phenol compound having at least one group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group. In the present invention, by including the component (B), coloring over time can be remarkably suppressed.
Examples of the alkyl group for R include those having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.
The number of groups —C (CH ₃ ) ₂ R in the phenyl group is preferably 1 or 2.

  (B) As a component, it is preferable that the compound represented by following formula (1) is included, and it is more preferable that it is only the compound represented by 1 type (s) or 2 or more types (1).

〔式（１）において、Ｒはアルキル基又はフェニル基を表し、Ｒ¹は水素原子、アルキル基又はフェニル基を表し、Ｒ²及びＲ³は水素原子又はメチル基を表し、Ｘはｍ価の基を表し、ｍは１〜４の整数を表す。〕

[In the formula (1), R represents an alkyl group or a phenyl group, R ¹ represents a hydrogen atom, an alkyl group or a phenyl group, R ² and R ³ represent a hydrogen atom or a methyl group, and X represents an m-valent group. Represents a group, and m represents an integer of 1 to 4. ]

In the formula (1), X is a monovalent or divalent group, and m is preferably an integer of 1 or 2.
The alkyl group in R ¹ of formula (1) is preferably an alkyl group having 1 to 20 carbon atoms.
As the compound of the formula (1), a compound represented by the following formula (1) ′ or / and the formula (1) ″ is preferable.

In the formula (1), specific examples of X include the following monovalent to tetravalent groups.
Examples of the monovalent group include an alkyl group, a group having one or more ester bonds (—COO— and / or —OCO—), a benzotriazoyl group, a group containing a hindered amino skeleton, and the like.
As the alkyl group, an alkyl group having 2 or more carbon atoms is preferable because it is excellent in preventing coloring of the cured product.
Examples of the group having one or more ester bonds include an alkoxycarbonylalkyl group, and a group represented by —R ⁷ COOR ¹ is preferable. Here, R ⁷ is an alkylene group having 1 to 12 carbon atoms such as an ethylene group, and R ¹ represents an alkyl group having 1 to 20 carbon atoms. R ⁷ is preferably an alkylene group having 2 to 6 carbon atoms.
Examples of the divalent group include an alkylene group and a group having one or more ester bonds. As the group having one or more ester bonds, two or more structures selected from the group consisting of monovalent to tetravalent alkyl groups, ester bonds, and ether bonds are linked, and one or more ester bonds are bonded. Examples thereof include divalent groups having a spiro orthoether ring and one or more ester bonds, and are preferably divalent groups.
Examples of the trivalent group include an isocyanur group (1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione-1,3,5-triyl group).
Examples of the tetravalent group include groups having one or more ester bonds, and two or more structures selected from the group consisting of monovalent to tetravalent alkyl groups, ester bonds, and ether bonds are linked. And tetravalent groups having one or more ester bonds are preferred. More ^{_{specifically, C (CH 2 OCOR 7 -}} ) 4 and the like. R ⁷ represents an alkylene group having 1 to 12 carbon atoms as described above, and is preferably the same as described above.

  The compound represented by the formula (1) is more preferably a compound (B1) [hereinafter referred to as component (B1)] in which X is a group having one or more ester bonds.

  In the component (B1), preferred examples of the monophenol compound include compounds represented by the following formula (2).

[However, in Formula (2), R < ⁴ > represents a C1-C20 alkyl group. ]
In the formula (2), when the carbon number of R ⁴ is 1 or more, the solubility in the composition is sufficient, and when the carbon number is 20 or less, a desired effect can be obtained with a small amount, A uniform composition is obtained.

As a specific example of the monophenol compound, a compound in which R ⁴ is —C ₁₈ H ₃₇ is preferable because it is easily available because it is sold by Asahi Denka Kogyo Co., Ltd. under the product name AO-50.

  In the component (B1), preferred examples of the diphenol compound include compounds represented by the following formula (3).

As the component (B), in addition to the above-described compounds, at least one group —C (CH ₃ ) ₂ R (R is an alkyl group or a phenyl group), which is known as an ultraviolet absorber. And a benzotriazole group (hereinafter referred to as component (B2)), which is known as a light stabilizer, at least one group —C (CH ₃ ) _{2 in the} phenyl group. A compound (B3) [hereinafter referred to as component (B3)] having R (R represents an alkyl group or a phenyl group) and further having a hindered amino group can also be mentioned.

As the component (B2), various compounds can be used as long as they have at least one group —C (CH ₃ ) ₂ R in the phenyl group and further have a benzotriazole group. Such compounds are commercially available, and examples thereof include TINUVIN series manufactured by Ciba Specialty Chemicals.
As the component (B2), a compound represented by the following formula (4) is more preferable.

[However, R ⁷ represents an alkyl group or a phenyl group having 1 to 10 carbon atoms. ]
In the formula (4), as R ⁷ , an alkyl group having 4 carbon atoms or a phenyl group is commercially available and can be suitably used.

As the component (B3), various compounds can be used as long as they are compounds having at least one group —C (CH ₃ ) ₂ R in the phenyl group and further having a hindered amino group. Such compounds are commercially available, and examples thereof include TINUVIN series manufactured by Ciba Specialty Chemicals.
As the component (B3), a compound represented by the following formula (5) is more preferable.

As the component (B), any of the components (B1) to (B3) described above can be used.
As a preferred form of use of the component (B), the component (B1) is essential, and the component (B2) or / and the component (B3) is used in combination. In this case, it is preferable because coloring of the substrate can be suppressed.

1-3. Component (C) The component (C) is a sulfur-based antioxidant which is a diester thioether compound represented by the following formula (6) or / and a tetraester thiocarbonate compound represented by the following formula (7). .
In this invention, there exists an effect which suppresses coloring in the case where light and heat are added to a laminated body simultaneously by including (C) component.
The component (C), compounds der having an oxidation preventing function has a sulfur atom is, for reasons of excellent coloring suppressing effect, to use the diester thioether compounds or / and tetraester type thiocarbonate compound.

The diester thioether compound in the component (C) or / and tetraester type carbonate compound, because they are low volatility, the diester thioether compounds, using the compound represented by the formula (6), tetraester As the type carbonate compound, a compound represented by the formula (7) is used .

[However, in the formula (6), R ⁵ represents an alkyl group having 1 to 20 carbon atoms. ]

[However, in Formula (7), R < ⁶ > represents a C1-C20 alkyl group. ]

In the formula (6) and (7), R ⁵ and R ⁶ is an alkyl group having 1 to 20 carbon atoms. When the carbon number of R ⁵ or R ⁶ is 1 or more, the composition has sufficient solubility, and when the carbon number is 20 or less, a desired effect can be obtained with a small amount, and a uniform composition can be obtained. A thing is obtained.

Specific examples of the diester type thioether compound include dioctyl thiodipropionate, dimyristyl-3,3-thiodipropionate, and the like.
Specific examples of the tetraester type thiocarbonate compound include pentaerythritol tetrakis (β-lauryl thiopropionate).

  By the way, it is a fact widely known in the field of plastic molding materials that the heat-resistant oxidative deterioration of a plastic material can be suppressed by using a phenol compound and a thioether compound in combination (Non-Patent Document 1).

JETI (Japan Energy & Technology Intelligence), Vol. 44, no. 5, 92-97 (1996)

  However, such knowledge has not been applied for the purpose of keeping coloring low in an active energy ray-curable composition, and moreover, in an active energy ray-curable adhesive composition, and in a combination different from the present invention, Coloring is greatly promoted by heat and light.

1-4. (D) Component In the composition of the present invention, a compound having an ethylenically unsaturated group is blended for the purpose of adjusting the viscosity of the composition and adjusting the intended physical properties.
As the component (D), various compounds can be used as long as they are compounds having an ethylenically unsaturated group other than the component (A). (D) As a component, there exist a monomer, an oligomer, and a polymer.

1) Examples of the monomer monomer include compounds having one (meth) acryloyl group.
Examples of the compound include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Alkyl (meth) acrylate; hydroxyl-containing (meth) acrylate such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; benzyl (meth) acrylate, o-phenylphenylethyl (meth) acrylate and p-cumylphenylethyl And aromatic group-containing (meth) acrylates such as (meth) acrylate; and alicyclic (meth) acrylates such as isobornyl (meth) acrylate.
In addition to (meth) acrylate, (meth) acrylamide derivatives such as N-methylacrylamide, N-isopropylacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide and acryloylmorpholine; N-vinylformamide N-vinyl compounds such as N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinylpyrrolidone and N-vinylcaprolactam.

  Among these, a hydroxyl group-containing (meth) acrylate is preferable because adhesion to the substrate can be improved. Further, when the composition is applied to an optical member or the like, an aromatic group-containing (meth) acrylate is preferable in that the cured product has an excellent refractive index, and (meth) acrylate having two aromatic groups. Is preferred.

  Examples of the compound having two or more (meth) acryloyl groups include ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. Alkylene glycol di (meth) acrylate; glycol di (meth) acrylate such as 1,6-hexanediol di (meth) acrylate and neopentyl glycol di (meth) acrylate; bisphenol A di (meth) acrylate or halogen aromatic nucleus substitution thereof And bisphenol F di (meth) acrylate or its halogen aromatic nucleus substituted bisphenol type di (meth) acrylate; dimethylol tricyclodecane di (meth) acrylate, trimethylol Polyol poly (meth) acrylates such as lopantri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate; Poly (meth) acrylates of adducts of alkylene oxide; di- or tri (meth) acrylates of isocyanuric acid alkylene oxides; in addition to these, the document "Latest UV Curing Technology" (printed information association, published in 1991) And compounds described on pages 53 to 56.

2) Examples of oligomers include polyester (meth) acrylate, epoxy (meth) acrylate, and polyether (meth) acrylate.

2-1) Polyester (meth) acrylate oligomer Examples of the polyester (meth) acrylate oligomer include a dehydration condensate of polyester polyol and (meth) acrylic acid.
Here, examples of the polyester polyol include a reaction product of a carboxylic acid with a polyol or an anhydride thereof.
Polyols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, butylene glycol, polybutylene glycol, tetramethylene glycol, hexamethylene glycol, neo Low molecular weight polyols such as pentyl glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, glycerin, pentaerythritol and dipentaerythritol, and their alkylene oxide adducts Etc.
As the carboxylic acid or anhydride thereof, dibasic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, fumaric acid, maleic acid, hexahydrophthalic acid, tetrahydrophthalic acid and trimellitic acid, or anhydrides thereof Thing etc. are mentioned.
Examples of the polyester poly (meth) acrylate other than these include compounds described on pages 74 to 76 of the above-mentioned document “UV / EB Curing Material”.

2-2) Epoxy (meth) acrylate oligomer Epoxy (meth) acrylate is a compound obtained by addition reaction of (meth) acrylic acid to an epoxy resin, and described in pages 74 to 75 of the above-mentioned document “UV / EB Curing Material”. And the like.
Examples of the epoxy resin include aromatic epoxy resins and aliphatic epoxy resins.

Specific examples of the aromatic epoxy resin include resorcinol diglycidyl ether; di- or polyglycidyl ether of bisphenol A, bisphenol F, bisphenol S, bisphenol fluorene or its alkylene oxide adducts; phenol novolac type epoxy resin and cresol novolac type Novolak type epoxy resins such as epoxy resins; glycidyl phthalimide; o-phthalic acid diglycidyl ester and the like.
In addition to these, the document “Epoxy Resin-Recent Advances” (Shojodo, published in 1990), Chapter 2 and the document “Polymer Processing”, Vol. 9, Volume 22 Special Issue Epoxy Resin (Polymer Publications, Compounds published on pages 4-6 and 9-16 of (Showa 48).

Specific examples of the aliphatic epoxy resin include diglycidyl ethers of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol; polyglycerides such as diglycidyl ethers of polyethylene glycol and polypropylene glycol. Diglycidyl ether of alkylene glycol; diglycidyl ether of neopentyl glycol, dibromoneopentyl glycol and its alkylene oxide adduct; di- or triglycidyl ether of trimethylolethane, trimethylolpropane, glycerin and its alkylene oxide adduct, and penta Polyglycerides of polyhydric alcohols such as di, tri or tetraglycidyl ethers of erythritol and its alkylene oxide adducts Ether; hydrogenated bisphenol A and di- or polyglycidyl ethers of alkylene oxide adducts; tetrahydrophthalic acid diglycidyl ether; hydroquinone diglycidyl ether, and the like.
In addition to these, the compounds described on pages 3 to 6 of the above-mentioned document “Polymer Processing”, separate volume epoxy resin, can be mentioned. In addition to these aromatic epoxy resins and aliphatic epoxy resins, epoxy compounds having a triazine nucleus as a skeleton, for example, TEPIC (Nissan Chemical Co., Ltd.), Denacol EX-310 (Nagase Kasei Co., Ltd.) and the like can be mentioned, Moreover, the compound etc. which are described in the said polymer "polymer processing" separate volume epoxy resin 289-296 pages are mentioned.
In the above, the alkylene oxide of the alkylene oxide adduct is preferably ethylene oxide or propylene oxide.

2-3) Polyether (meth) acrylate oligomer Polyether (meth) acrylate oligomer includes polyalkylene glycol (meth) diacrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate and polytetra And methylene glycol di (meth) acrylate.

3) As the polymer polymer, a (meth) acrylic polymer having a (meth) acryloyloxy group, a (meth) acrylic polymer having a functional group, a (meth) acryloyl group introduced into the side chain, Examples thereof include compounds described on pages 78 to 79 of the document “UV / EB Curing Material”.

1-5. In the present invention, as the ratio of the components (A), (B), (C) and (D), the total amount of the components (A), (B), (C) and (D) is 100% by weight. In this case, (A) component 5 to 50% by weight, (B) component 0.01 to 5% by weight, (C) component 0.01 to 5% by weight, and (D) component 50 to 95% by weight are preferable. More preferred ranges are (A) component 15 to 40% by weight, (B) component 0.05 to 1% by weight, (C) component 0.05 to 1% by weight, and (D) component 50 to 80% by weight. When the proportion of the component (A) is 5% by weight or more, the adhesive strength at high temperature is excellent, and when it is 50% by weight or less, the initial adhesive strength or adhesive strength under high humidity is excellent. It becomes. When the components (B) and (C) are each 0.01% by weight or more, the cured product obtained by curing the composition is less colored by heat or light, and when it is 5% by weight or less, no precipitation occurs. A uniform composition is obtained and the curability is excellent. When the component (D) is 90% by weight or less, the initial adhesive force and the adhesive force at high temperature or high humidity are excellent.

Further, the composition of the present invention preferably contains 2 to 30% by weight of a methacrylate compound in the total amount of the components (A) and (D) in order to prevent appearance defects such as wrinkles and warpage of the base film to be bonded. . By including these methacrylate compounds in the composition, the curing rate of the composition can be adjusted. When it is 2% by weight or more, the adhesive strength is excellent, and when it is 30% by weight or less, the curability and productivity are excellent.
The methacrylate compound may be appropriately selected from the aforementioned components (A) and (D).

In applications that require a small initial coloration, the compound having an aromatic group and an ethylenically unsaturated group is less than 50% by weight in the total amount of the component (A) and the component (D). Preferably, it is less than 30% by weight, and most preferably does not contain the compound.
On the other hand, in applications where the refractive index of the cured product is required, the compound having an aromatic group and an ethylenically unsaturated group is contained in 50% by weight or more and 80% by weight in the total amount of the component (A) and the component (D) % Or less is preferable.
What is necessary is just to select suitably from the above-mentioned (D) component as a compound which has the said aromatic group and ethylenically unsaturated group.

1-6. Other Components When the composition of the present invention is cured by ultraviolet rays, a photopolymerization initiator can be blended as necessary.
Photopolymerization initiators include benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenyl Acetophenones such as acetophenone, 1,1-dichloroacetophenone, 1-hydroxyacetophenone, 1-hydroxycyclohexyl phenyl ketone and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one; 2 -Anthraquinones such as methyl anthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxan Thioxanthone such as 2,4-diethylthioxanthone, 2-chlorothioxanthone and 2,4-diisopropylpyroxanthone; ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; 2,4,6-trimethylbenzoyl diphenylphosphine oxide and the like Examples thereof include phosphine oxides such as monoacylphosphine oxide and bisacylphosphine oxide; benzophenones such as benzophenone; and xanthone. These photopolymerization initiators can be used alone or in combination with a benzoic acid-based or amine-based photopolymerization initiation accelerator.
A preferable blending ratio of the photopolymerization initiator is 0.1% by weight or more and 10% by weight or less, and more preferably 0.5% by weight or more and 5% by weight or less with respect to 100% by weight of the composition.
An α-hydroxyacetophenone-based or phosphine oxide-based photopolymerization initiator is preferred because of less coloring over time.

  The composition of the present invention contains other antioxidants in an amount of up to 5% by weight per 100% by weight of the total of components (A) to (D) and optionally (E), (B2 ) UV absorbers other than the components, (B3) Durability improvers such as light stabilizers (HALS (hindered amine light stabilizer), etc.), etc., and leveling agents for making the coating film thickness uniform An antifoaming agent for suppressing foaming can be added.

1-7. Production and Use Method The production method of the composition of the present invention is not particularly limited, and the essential component of the present invention, or the essential component and other components as necessary are stirred or mixed by a commonly used method. Is obtained.

As a glass transition temperature (henceforth Tg) after hardening of a composition, 10 to 70 degreeC is preferable. When Tg is 10 ° C. or higher, sufficient adhesive strength is obtained during the heat resistance test, and when Tg is 70 ° C. or lower, initial peel strength is sufficiently obtained.
In the present invention, Tg means a temperature at which the main peak of the loss tangent (tan δ) of the viscoelastic spectrum of the cured product measured at 1 Hz is maximized.

2. Polarizing film The polarizing film used in the present invention has a function of selectively transmitting linearly polarized light in one direction from natural light.

Specific examples of the polarizing film include an iodine polarizing film obtained by adsorbing and aligning iodine on a polyvinyl alcohol film, a dye polarizing film obtained by adsorbing and aligning a dichroic dye on the polyvinyl alcohol film, and (lyotropic) liquid crystal. Examples thereof include a coating type polarizer coated with a dye in a state, oriented and fixed.
These iodine-based polarizing films, dye-based polarizing films, and coating-type polarizers have a function of selectively transmitting one direction of linearly polarized light from natural light and absorbing the other one direction of linearly polarized light. It is called a type polarizer.

In the said iodine type polarizing film and dye-type polarizing film, what provided the protective layer in the single side | surface or both surfaces can also be used normally.
In a polarizing plate provided with a protective layer only on one side, the surface to be bonded to the retardation film may be a surface with a protective layer or a surface without a protective layer.
Examples of the protective layer include cellulose acetate resin films such as triacetyl cellulose and diacetyl cellulose, acrylic resin films, polyester resin films, polyarylate resin films, polyether sulfone resin films, and cyclic olefins such as norbornene. The thing which bonded the cyclic polyolefin resin film etc. to do is mentioned.
The protective layer is not limited to a film. For example, it may be a protective layer formed by coating.
The polarizing film used in the present invention is not limited to the absorptive polarizing film described above, but a reflective type having a function of selectively transmitting linearly polarized light in one direction from natural light and reflecting or scattering the linearly polarized light in another direction. What is called a polarizer or a scattering polarizer may be used. Moreover, the polarizer specifically mentioned above is not necessarily limited to these, and any polarizer having a function of selectively transmitting linearly polarized light in one direction from natural light may be used.
Among these polarizing films, it is preferable to use an absorption polarizing plate excellent in visibility, and among them, it is most preferable to use an iodine polarizing plate excellent in polarization degree and transmittance.

3. The retardation film retardation film, various materials can be used, an optical film for processing has been performed, such as uniaxial or biaxial stretching, or a liquid crystalline compound or the like is applied to a substrate, the orientation, the immobilized Examples include a processed optical film and the like, in which the magnitude relationship (refractive index ellipsoid) of the three-dimensional refractive index is controlled according to the use conditions. It is mainly used to compensate for coloration of the liquid crystal layer of a liquid crystal display and to compensate for changes in phase difference due to viewing angle.

Specific examples of retardation films include optical film materials that are subjected to processing such as stretching, polyolefins such as polyethylene, polypropylene, and cyclic polyolefins, polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyarylate. And polyamide.
The above-mentioned cyclic polyolefin is a general generic name for resins obtained from cyclic olefins such as norbornene, tetracyclododecene, and derivatives thereof. For example, JP-A-3-14882 and JP-A-3-122137. Etc. are mentioned.
Specifically, ring-opening polymers of cyclic olefins, addition polymers of cyclic olefins, random copolymers of cyclic olefins and α-olefins such as ethylene and propylene, and these are modified with unsaturated carboxylic acids or their derivatives. Examples of such graft-modified products can be given. Furthermore, these hydrides are mentioned. Examples of the products include ZEONEX and ZEONOR manufactured by Nippon Zeon Co., Ltd., Arton manufactured by JSR Corporation, and TOPAS manufactured by TICONA.

  In addition, as optical films coated with liquid crystalline compounds, etc. and processed for orientation and fixation, "WV film" (Fuji Photo Film Co., Ltd.), "LC film", "NH film" (Both made by Nippon Oil Corporation).

4). TECHNICAL FIELD The present invention relates to a method for producing a polarizing plate comprising the following steps [1] to [3].
[1] A step of applying the following active energy ray-curable adhesive composition to a polarizing film or a retardation film
[2] A step of bonding the retardation film or the polarizing film to the polarizing film or the retardation film coated with the composition, respectively.
[3] A process of irradiating active energy rays from the surface of any substrate after bonding any film

In the step [1], the active energy ray-curable adhesive composition is applied to a polarizing film or a retardation film.
As a coating method of the composition, a conventionally known method may be followed, natural coater, knife belt coater, floating knife, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, Examples include air blades, curtain flow coaters, and gravure coaters.
Moreover, what is necessary is just to select the application | coating thickness of a composition according to the polarizing film to be used, retardation film, and a use, Preferably it is 0.1-1,000 micrometers, More preferably, it is 1-50 micrometers.

In the step [2], the retardation film or polarizing film is bonded to the polarizing film or retardation film coated with the composition.
As a method of laminating these films, a conventional method may be followed.

In the step [3], after any film is bonded, active energy rays are irradiated from the surface of any substrate.
Irradiation of active energy rays may be performed from the polarizing film side or the retardation film side, depending on the type of film used.
Examples of the active energy ray include ultraviolet rays, X-rays, and electron beams, but ultraviolet rays are preferable because inexpensive devices can be used. Various light sources can be used for curing with ultraviolet rays, and examples thereof include a pressurized or high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge lamp, and a carbon arc lamp. In the case of curing with an electron beam, various devices can be used as an EB irradiation device that can be used, such as a Cockloft-Walton type, a bandegraph type, and a resonance transformer type device. Those having an energy of 1,000 eV are preferred, more preferably 100 to 300 eV.

When the polarizing plate of the present invention is used as a circularly polarizing plate, a retardation film having a different retardation is further bonded to the retardation film side of the obtained composite polarizing plate in order to obtain a circularly polarized state over a wide band. You can also
Specifically, there is a method in which a retardation film having a ½ wavelength with respect to each wavelength is bonded to a polarizing film, and a retardation film having a ¼ wavelength is bonded to each wavelength. .

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following examples, “part” means wt%.

○ Production Examples 1-7
The components (A) to (E) and the photopolymerization initiator shown in Table 1 below were dissolved by heating and stirring at 60 ° C. for 1 hour to produce an active energy ray-curable adhesive composition. Table 2 summarizes the proportion (% by weight) of methacrylate (hereinafter also referred to as “MA ratio”) in the total number of parts (A) and (D) of each composition.
The obtained composition was evaluated according to the following test method. The results are shown in Table 3.

In Table 1, each number means the number of copies, and each abbreviation means the following.
1) M-1200: urethane acrylate having a non-aromatic polyester skeleton, weight average molecular weight of about 5,000 [Aronix M-1200 manufactured by Toagosei Co., Ltd.]
2) UN-9200: Urethane acrylate having a non-aromatic polycarbonate skeleton, weight average molecular weight of about 20,000 [Negami Kogyo Co., Ltd. Art Resin UN-9200A]
3) AO-50: Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate [AO-50 manufactured by Asahi Denka Kogyo Co., Ltd., wherein R ¹ is an octadecyl group Some compounds
4) AO-80: 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4 8,10-tetraoxaspiro [5.5] undecane [AO-80 manufactured by Asahi Denka Kogyo Co., Ltd., compound of formula (4)]
5) TV900: 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol [TINUVIN900 manufactured by Ciba Specialty Chemicals, R ⁴ in formula (5) Is a phenyl group]
6) TV928: 2- (2H-benzotriazol-2-yl) -4- (1,1-dimethyl-3,3-dimethylbutyl-6- (1-methyl-1-phenylethyl) phenol [Ciba Specialty -Chemicals TINUVIN928, a compound in which R ⁴ is a methyl group in formula (5)]
7) TV144: bis (1,2,2,6,6-pentaethyl-4-piperidyl) [3,5-bis (1,1-dimethyl) -4-hydroxyphenyl] butyl malonate [Ciba Specialty Chemicals TINUVIN144, compound of formula (6)]
8) Sum: Dimyristyl-3,3′-thiodipropionate [SumilizerTPM manufactured by Sumitomo Chemical Co., Ltd.]
9) AO-412: Pentaerythritol tetrakis (β-laurylthiopropionate) [AO-412S manufactured by Asahi Denka Kogyo Co., Ltd.]
10) IBX: Isobornyl methacrylate [Light Ester IB-X manufactured by Kyoeisha Chemical Co., Ltd.]
11) IBXA: Isobornyl acrylate [Kyoeisha Chemical Co., Ltd. light acrylate IB-XA]
12) HEMA: Hydroxyethyl methacrylate [Kyoeisha Chemical Co., Ltd. Light Ester HO]
13) OPPA: Orthophenylphenol acrylate [Aronix TO-2344, manufactured by Toagosei Co., Ltd.]
14) Irg184: 1-hydroxycyclohexyl phenyl ketone [Irgacure 184 manufactured by Ciba Specialty Chemicals]
15) TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide [Lucirin TPO manufactured by BASF]

Examples 1 to 7 (experiment assuming adhesion between a polarizing film with a double-sided TAC and a retardation film)
180 μm thick cycloolefin resin film [manufactured by Nippon Zeon Co., Ltd. Product name Zeonoa. On the film, the obtained composition was applied to a thickness of 10 μm by a bar coater. Triacetyl cellulose [manufactured by Lonza Corporation] having a thickness of 100 μm. Hereinafter, it is abbreviated as TAC. ) After pasting the film together by nip roll, this was passed twice under the condition of 120 W / cm, 10 cm from the bottom of the concentrating metal halide lamp at a conveyor speed of 5 m / min. A laminated film (laminated film) was produced by bonding. This is called specimen A.
In the above, a polyethylene terephthalate (hereinafter abbreviated as PET) film having a thickness of 50 μm was stacked on the TAC film side of the obtained laminated film. This is called specimen B.
Using the obtained specimen A, the peel strength was evaluated after being left under the following conditions.
-Initial: 30 minutes at room temperature-After high-temperature test: 500 hours at 90 ° C-After high-humidity test: 500 hours under conditions of 70 ° C and 95% RH After standing, coloring was evaluated.
After high temperature test: 500 hours at 90 ° C. After high humidity test: 500 hours under the conditions of 70 ° C. and 95% RH Light resistance test: 250 J / cm ² (UV) for the laminate film using a high-pressure mercury lamp -A) UV irradiation was performed.

(2) Peel strength After the test body A was subjected to a high temperature test or a high humidity test under the above conditions, the peel strength was measured with a tensile tester under the following conditions.
Test piece: 25 mm x 100 mm
Peeling angle: 180 degrees Peeling speed: 200 mm / min
In addition, when the adhesive strength was sufficiently strong and the base material was torn at the time of measuring the peel strength, it was described as base material destruction.

(3) Measurement of coloring Using an integrating sphere type spectral transmittance measuring device (DOT-3C manufactured by Murakami Color Material Research Laboratory Co., Ltd.), the YI value of the specimen B before the test, and the high temperature test, high humidity test and The YI value of the specimen B after the light resistance test was measured. In the table below, the coloring after each test is indicated by ΔYI (difference between the YI value of the specimen B after each test and the YI value of the specimen B before each test).

○ Examples 8 to 14 (experiment assuming adhesion of polarizing film with double-sided TAC and retardation film)
In Examples 1 to 7, laminated films were produced in the same manner except that a 100 μm Arton film [manufactured by JSR Co., Ltd.] was used instead of the ZEONOR film.
Table 4 shows the results of testing the obtained laminated film in the same manner as described above.

○ Comparative Production Examples 1 to 7
An active energy ray-curable adhesive composition was produced in the same manner as in Production Examples except that the components shown in Table 5 below were used. Table 6 summarizes the MA ratio of each composition.
The obtained composition was evaluated in the same manner as in the examples. The results are shown in Table 5.

In Table 5, each number means the number of copies, and each abbreviation has the same meaning as in Table 1 except for the following.
16) M-1600: Polyether urethane acrylate, weight average molecular weight of about 3,000 [Aronix M-1600 manufactured by Toagosei Co., Ltd.]
17) SZ-3: 1,2-bis (2-hydroxyethylthio) ethane [SZ-3 manufactured by Sakai Chemical Co., Ltd.]

○ Comparative Examples 1-7
In Examples 1 to 7, laminated films were produced in the same manner except that the compositions obtained in Comparative Production Examples were used.
Table 7 shows the results of testing the obtained laminated film in the same manner as described above.

○ Examples 15 to 21
A polarizing plate was produced in the same manner as in Examples 1 to 7 except that a commercially available polarizing film and retardation film were used, and as a result, it had the same adhesiveness as described above.

  The polarizing plate of the present invention can be used for various applications, and can be particularly preferably used for producing an image display device such as a liquid crystal panel.

Claims (9)

A method for producing a polarizing plate with a retardation film, comprising the following steps [1] to [3].
[1] A step of applying the following active energy ray-curable adhesive composition to a polarizing film or a retardation film
[2] A step of bonding the retardation film or the polarizing film to the polarizing film or the retardation film coated with the composition, respectively.
[3] A process of irradiating active energy rays from the surface of any of the substrates after bonding any of the films ○ Active energy ray-curable adhesive composition: including the following components (A) to (D) An active energy ray-curable adhesive composition.
(A) Urethane (meth) acrylate having a polyester skeleton or a polycarbonate skeleton (B) A phenol compound having at least one group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group. (C) Sulfur antioxidant which is a diester type thioether compound represented by the following formula (6) and / or a tetraester type thiocarbonate compound represented by the following formula (7) (D) Other than the component (A) Compounds having an ethylenically unsaturated group

[However, in the formula (6), R ⁵ represents an alkyl group having 1 to 20 carbon atoms. ]

[However, in Formula (7), R < ⁶ > represents a C1-C20 alkyl group. ] When the total amount of the components (A), (B), (C) and (D) is 100% by weight, the component (A) is 5 to 50% by weight, and the component (B) is 0.01 to 2. The method for producing a polarizing plate with a retardation film according to claim 1, comprising 5 wt%, (C) component 0.01 to 5 wt% and (D) component 50 to 95 wt%. The manufacturing method of the polarizing plate with retardation film of Claim 1 or Claim 2 in which the said (B) component contains the compound represented by following formula (1).

[In the formula (1), R represents an alkyl group or a phenyl group, R ¹ represents a hydrogen atom, an alkyl group or a phenyl group, R ² and R ³ represent a hydrogen atom or a methyl group, and X represents an m-valent group. Represents a group, and m represents an integer of 1 to 4. ] The manufacturing method of the polarizing plate with a phase difference film of Claim 3 in which the said (B) component contains the compound (B1) whose X in said Formula (1) is group which has one or more ester bonds. The method for producing a polarizing plate with a retardation film according to claim 4, wherein (B1) is a compound represented by the following formula (2).

[However, in Formula (2), R < ⁴ > represents a C1-C20 alkyl group. ] The method for producing a polarizing plate with a retardation film according to claim 4, wherein (B1) is a compound represented by the following formula (3).

The component (B) has the above (B1) and at least one group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group, and further has a benzotriazoyl group. And / or a compound (B3) having at least a group —C (CH ₃ ) ₂ R (R represents an alkyl group or a phenyl group) in the phenyl group and further having a hindered amino group. The manufacturing method of the polarizing plate with retardation film as described in any one of Claims 4-6. Phase difference method of producing a film with the polarizing plate according to any one of claims 1 to 7 further comprising a photopolymerization initiator. The method for producing a polarizing plate with a retardation film according to any one of claims 1 to 8 , wherein the total amount of the component (A) and the component (D) contains 2 to 30% by weight of a methacrylate compound.