JP2014010311A - Polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate with a cured product having a low photoelastic coefficient, capable of being manufactured without using an adhesive or the like and making a thickness of a polarizer protective film less than 40 μm.SOLUTION: A polarizing plate is made by directly forming, as a protective film, a film-shaped or sheet-shaped cured product of an active energy ray-curable composition on at least one side surface of a polarizer formed from a polyvinyl alcohol resin. A photoelastic coefficient of the cured product at 23°C is 15×10Paor less.

Description

The present invention relates to a polarizing plate having a film-like or sheet-like cured product of an active energy ray-curable composition as a protective film, and belongs to these technical fields.
In the following, for convenience, unless otherwise specified, a film or sheet is represented as “film”, and acrylate or methacrylate is represented as (meth) acrylate.

  In recent years, liquid crystal display devices with integrated touch panels have been increasingly applied to mobile devices such as smartphones, tablet terminals, car navigation systems, etc. Accordingly, the polarizing plates that make up liquid crystal display devices have become thinner and lighter. In addition, high durability has been demanded. In addition, a liquid crystal display device for mobile use is required to be usable under wet heat, and a polarizing plate used therefor is also required to have high wet heat resistance. On the other hand, a polarizing plate on which a triacetyl cellulose (hereinafter referred to as “TAC”) film is bonded as an optical film such as a polarizer protective film or a retardation film for optically compensating a liquid crystal is used in a high humidity environment, particularly at high temperatures. When exposed to a humid environment for a long period of time, there are problems that the polarization performance deteriorates and the polarizer contracts. Accordingly, the protective layer laminated on the polarizer is required to improve the mechanical strength and the ability to suppress the contraction of the polarizer (shrinkage suppressing force) as well as reducing the thickness and weight and increasing the hardness. .

  In the conventional method of adhering a protective film made of a TAC film to a polarizer, it is difficult to make the protective film less than 40 μm from the viewpoint of handling and durability during work, and there is a limit to reducing the thickness and weight. .

  As a protective film, a cured film of an active energy ray-curable composition containing urethane (meth) acrylate has been studied. However, in the method of bonding this to a polarizer, the film is torn when the protective film is 40 μm or less. It became easier, and stable processing could not be performed when processing with the roll-to-roll method, and there was a limit to reducing the thickness and weight.

  In order to solve such a problem, a technique for directly forming a protective film on at least one surface of a polarizer is disclosed.

  In Patent Document 1, a protective film is formed on a polarizer by curing an active energy ray-curable composition containing an active energy ray-polymerizable compound having a dicyclopentanyl residue or a dicyclopentenyl residue. Techniques to do this are disclosed.

  Patent Document 2 discloses a polarizing plate having a protective film mainly composed of an epoxy resin on at least one surface of a polarizing film.

  Patent Document 3 discloses that at least one surface of a polarizer is protected with a cured product of an active energy ray-curable resin composition mainly composed of a (meth) acrylic acid ester or an epoxy compound and an oxetane compound.

  However, none of Patent Documents 1 to 3 describes or suggests a photoelastic coefficient. When the polarizer protective film used on the liquid crystal cell side is made of a material that easily causes birefringence changes due to external force, there is a problem that birefringence distribution occurs and the contrast becomes non-uniform. The ease with which birefringence changes due to external force are expressed by the absolute value of the photoelastic coefficient, but when the materials described in Patent Documents 1 to 3 are used as the polarizer protective film, the absolute value of the photoelastic coefficient is large. The light birefringence occurs due to the occurrence of stress birefringence accompanying the polarizer contraction.

JP 2003-185842 A JP 2004-245924 A JP 2005-92112 A

  An object of the present invention is to provide a polarizing plate that can be produced without using an adhesive or the like, the thickness of the polarizer protective film can be less than 40 μm, and the photoelastic coefficient of the cured product is low. That is.

  As a result of intensive studies to solve the above problems, the present inventors have directly applied a film-like cured product of an active energy ray-curable composition having a specific photoelastic coefficient as a polarizer protective film to a polarizer. It was found that the formed polarizing plate was effective, and the present invention was completed.

  According to the composition of the present invention, it is possible to provide a polarizing plate in which a protective film having a thin film of less than 40 μm and a low photoelastic coefficient is directly formed on a polarizer by a simple manufacturing method without using an adhesive or the like. it can.

FIG. 1 shows an example of the production of the polarizing plate of the present invention. FIG. 2 shows an example of the production of the polarizing plate of the present invention.

In the present invention, an active energy ray-curable composition (hereinafter simply referred to as “composition”) is used as a protective film on at least one surface of a polarizer (hereinafter simply referred to as “polarizer”) formed from a polyvinyl alcohol resin. A polarizing plate directly formed with a film-like cured product (hereinafter simply referred to as “cured product”), wherein the cured product has a photoelastic coefficient at 23 ° C. (hereinafter simply referred to as “photoelastic coefficient”). The present invention relates to a polarizing plate that is 15 × 10 ⁻¹² Pa ⁻¹ or less.
Details of the present invention will be described below. In the present specification, a crosslinked product and a cured product obtained by irradiating the composition with active energy rays are collectively referred to as a “cured product”.

1. Polarizer The polarizer used in the polarizing plate of the present invention is one formed from a polyvinyl alcohol resin.
As the polarizer, various materials can be used as long as they have a function of selectively transmitting linearly polarized light in one direction from natural light.
For example, an iodine polarizing film in which iodine is adsorbed and oriented on a polyvinyl alcohol film, a dye polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol film, and a dichroic dye is coated. Examples include a fixed coating type polarizer. These iodine-based polarizing films, dye-based polarizing films, and coating-type polarizers have a function of selectively transmitting linearly polarized light in one direction from natural light and absorbing linearly polarized light in the other direction. It is called a polarizer.
Among these polarizers, it is preferable to use an absorptive polarizer having excellent visibility. The thickness of the absorption polarizer is preferably 5 to 40 μm.

2. Active energy ray-curable composition The polarizing plate of the present invention is obtained by directly forming a film-like cured product of an active energy ray-curable composition as a protective film on at least one surface of a polarizer.
And as the said composition, the thing whose photoelastic coefficient of hardened | cured material is 15 * 10 <^-12> Pa <^-1> or less is used. When the photoelastic coefficient of the cured product of the composition is greater than 15 × 10 ⁻¹² Pa ^{−1, a} liquid crystal display is likely to cause light leakage and white spots.
The photoelastic coefficient of the cured product of the composition is preferably −10 × 10 ⁻¹² to 10 × 10 ⁻¹² Pa ⁻¹ , more preferably −5 × 10 ^{−12 to} 5 × 10 ⁻¹² Pa ⁻¹ . .

In the present invention, the photoelastic coefficient is a coefficient representing the ease of occurrence of a change in birefringence due to an external force, and means that the change in birefringence due to an external force is smaller as the value of the photoelastic coefficient is closer to zero.
Specifically, the photoelastic coefficient (C) is a value defined by the following equation, where σ is an extensional stress and Δn is a birefringence when stress is applied.
C [Pa ⁻¹ ] = Δn / σ
Here, Δn is defined by the following equation, where n ₁ is the refractive index in the direction parallel to the stretching direction and n ₂ is the refractive index in the direction perpendicular to the stretching direction.
Δn = n ₁ −n ₂
In addition, the photoelastic coefficient in this invention means the value measured at the temperature of 23 degreeC.

As the composition, various compositions can be used as long as the cured product of the composition satisfies the photoelastic coefficient and can form a polarizing plate protective film.
Among them, a composition containing urethane (meth) acrylate (A) [hereinafter referred to as “component (A)”] is preferable in that the obtained cured product is excellent in mechanical properties.
Hereinafter, the composition containing the component (A) will be described.

2-1. (A) Component Examples of the component (A) include a reaction product of a polyol, an organic polyisocyanate and a hydroxyl group-containing (meth) acrylate.
The component (A) is a urethane (meth) acrylate having two or more (meth) acryloyl groups, and a urethane (meth) acrylate having two (meth) acryloyl groups is preferable.
As the component (A), urethane (meth) acrylate having no aromatic group is preferable because it has a low photoelastic coefficient. A urethane (meth) acrylate having no aromatic group can be produced by using a compound having no aromatic group as a raw material polyol and organic polyisocyanate.
(A) As a weight average molecular weight (henceforth "Mw") of a component, a thing of 1,000-15,000 is preferable, More preferably, it is 1,000-10,000.
In the present invention, Mw is a value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter referred to as “GPC”) into polystyrene.
(A) A component may use only 1 type or may use 2 or more types together.
Hereinafter, the polyol, the organic polyisocyanate and the hydroxyl group-containing (meth) acrylate, which are the raw material compounds of the component (A), and the method for producing the component (A) will be described.

2-1-1. As the polyol polyol, a diol is preferably used, and various diols can be used.
Furthermore, examples of the polyol include a polyol having a hydroxyl number-based number average molecular weight (hereinafter referred to as “P-Mn”) having a P-Mn of less than 500 and a polyol having a P-Mn of 500 or more.
In addition, in this invention, P-Mn (number average molecular weight) of a polyol means the value calculated | required according to the following formula.

  Examples of the polyol having a P-Mn of less than 500 include aliphatic diols having 2 to 12 carbon atoms and alicyclic diols having 2 to 12 carbon atoms.

  Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, , 5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexane glycol, 2,2,4-trimethyl-1,3 -Aliphatic diols such as pentanediol, 3,3-dimethylolheptane, 1,9-nonanediol and 2-methyl-1,8-octanediol.

Examples of the alicyclic diol having 2 to 12 carbon atoms include cyclohexanedimethanol, hydrogenated bisphenol-A, tricyclo [5.2.1.0 ^2,6 ] decanedimethanol (common name: tricyclodecanedimethanol), 1 , 4-decahydronaphthalenediol, 1,5-decahydronaphthalenediol, 1,6-decahydronaphthalenediol, 2,6-decahydronaphthalenediol, 2,7-decahydronaphthalenediol, decahydronaphthalenediol, Norbornanediol, norbornanedimethanol, decalindimethanol, adamantanediol, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane ( Common name; spiroglycol), isosorbide, isomannide, , 2-bis (4-hydroxycyclohexyl) propane (common name; hydrogenated bisphenol A), 4,4'-dihydroxydicyclohexylmethane (common name; hydrogenated bisphenol F), 1,1-bis (4-hydroxycyclohexyl) -1 , 1-dicyclohexylmethane (common name; hydrogenated bisphenol Z), and alicyclic diols such as 4,4-bicyclohexanol.

Among these compounds, a polyol having a P-Mn of 60 or more and 400 or less is preferable.
Specific examples of the compound include aliphatic diols having 2 to 6 carbon atoms such as 1,4-butanediol, tricyclo [5.2.1.0 ^2,6 ] decandimethanol, and 3,9-bis (1 , 1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane and other alicyclic diols having a plurality of rings are preferable, and the strength of the cured product is excellent. 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (common name; spiroglycol) is particularly preferred.

  Examples of the polyol having P-Mn of 500 or more include polycarbonate diol, polyester diol, and polyether diol.

Examples of the polycarbonate diol include a reaction product of a low molecular weight diol or / and a polyether diol and a dialkyl ester carbonate such as ethylene carbonate and dibutyl carbonate.
Here, examples of the low molecular weight diol include ethylene glycol, propylene glycol, cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, and the like.
Examples of polyether diols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and block or random polymer diols such as polyethylene polypropoxy block polymer diols.

  The polyester diol is an ester of the low molecular weight diol or / and the polyether diol with an acid component such as a dipic acid such as adipic acid, succinic acid, tetrahydrophthalic acid and hexahydrophthalic acid or an anhydride thereof. And the like.

  Examples of polyether diols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; block or random polymer diols such as polyethylene polypropoxy block polymer diols, and the like.

  As the polyol, in order to improve the mechanical strength of the cured product, it is preferable to use a triol in addition to the diol.

  Triols include 1,2,6-hexanetriol, 1,2,3-heptanetriol, 1,2,4-butanetriol, trimethylolpropane, trimethylolethane, kacilitol, pyrogallol, glycerin and tris (2-hydroxy). Ethyl) isocyanurate and the like, and adducts of these triols such as ε-caprolactone, ethylene oxide and propylene oxide.

As the caprolactone adduct of triol, a caprolactone adduct of trimethylolpropane and a caprolactone adduct of glycerin are preferable. The triol caprolactone adduct is preferably a compound having an average hydroxyl value of 300 to 600 mgKOH / g and an average number of hydroxyl groups of 3.
The trica-cacaprolactone adduct is commercially available, and examples thereof include Plaxel 303, 305, 308, 312 and L320ML (manufactured by Daicel Corporation).

These polyols may be used alone or in combination of two or more.
When brittleness and flexibility are required as the component (A), it is more preferable to use an aliphatic diol having 2 to 12 carbon atoms or an alicyclic diol having 2 to 12 carbon atoms as the polyol.
As the component (A), when mechanical properties are required, more specifically, when excellent in breaking strength and tensile elastic modulus are required, a polyol having a P-Mn of 500 or more and P-Mn as a polyol It is preferable to use a combination of polyols having a molecular weight of less than 500.

  More specifically, examples of the polyol having a P-Mn of 500 or more include polycarbonate diol and polyester diol, and examples of the polyol having a P-Mn of less than 500 include an aliphatic diol having 2 to 12 carbon atoms and 2 to 12 carbon atoms. These alicyclic diols can be mentioned, and these are used in combination.

  These polyols may be used alone or in combination of two or more.

2-1-2. Organic polyisocyanate As organic polyisocyanate, organic diisocyanate is preferable, and non-yellowing type organic diisocyanate is more preferable.
Non-yellowing organic diisocyanates include hexamethylene diisocyanate, lysine methyl ester diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate and other aliphatic diisocyanates, isophorone diisocyanate (hereinafter referred to as “IPDI”), 4, Examples include alicyclic diisocyanates such as 4'-methylenebis (cyclohexyl isocyanate), norbornane diisocyanate, and ω, ω'-diisocyanate dimethylcyclohexane.

  These organic polyisocyanates may be used alone or in combination of two or more.

  Among the above-mentioned compounds, IPDI is preferable because it is excellent in mechanical strength and optical properties of the cured product.

2-1-3. Hydroxyl group-containing (meth) acrylate As hydroxyl group-containing (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polycaprolactone-modified hydroxyethyl acrylate , Hydroxyalkyls such as hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, pentaerythritol tri, di or mono (meth) acrylate, and trimethylolpropane di or mono (meth) acrylate ( And (meth) acrylate.
Among the above-mentioned compounds, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like in that the curability of the composition and the flexibility of the cured product are excellent. Polycaprolactone-modified hydroxyethyl acrylate is preferred.

2-1-4. (A) Manufacturing method of component (A) The component may be manufactured according to a conventional method.
As the component (A), a polyol and an organic polyisocyanate are reacted to produce an isocyanate group-containing compound, a compound obtained by reacting this with a hydroxyl group-containing (meth) acrylate (hereinafter referred to as “compound A1”), a polyol, Examples thereof include a compound obtained by reacting an organic polyisocyanate and a hydroxyl group-containing (meth) acrylate at the same time (hereinafter referred to as “compound A2”), and the compound A1 is preferable because the molecular weight is easily controlled.
In the case of producing compound A1, in the presence of a urethanization catalyst such as dibutyltin dilaurate, the polyol and organic polyisocyanate to be used are heated and stirred for addition reaction, and further hydroxyalkyl (meth) acrylate is added, and heated and stirred for addition reaction. Examples of the method for producing compound A2 include a method in which a polyol, an organic polyisocyanate and a hydroxyalkyl (meth) acrylate are simultaneously added and heated and stirred in the presence of the same catalyst as described above.

  A catalyst for urethanization can be added to these reactions. Specific examples include tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctate and dibutyltin diacetylacetonate, bismuth compounds such as bismuth dioctate, and calcium compounds such as calcium dioctate.

These reactions can be carried out without solvent or in the presence of a solvent.
Specific examples of the solvent include hydrocarbon solvents such as n-hexane, benzene, toluene, xylene, ethylbenzene and cyclohexane; tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, bis (2-methoxy Ether solvents such as ethyl) ether, bis (2-ethoxyethyl) ether and bis (2-butoxyethyl) ether; acetone, methyl ethyl ketone, methyl-n-propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, methyl Ketone solvents such as pentyl ketone, di-n-propyl ketone, diisobutyl ketone, holon, isophorone, cyclohexanone and methylcyclohexanone; propylene glycol mono Ethyl acetate, butyl acetate and like esters; alkylene glycol monoether acetates, such as chill ether acetate and N- methylpyrrolidone and the like.
Of these, methyl ethyl ketone and methyl isobutyl ketone are particularly preferable from the viewpoints of solubility of urethane (meth) acrylate and easiness of evaporation.

  A reactive diluent can be used in place of the solvent in order to reduce the viscosity of urethane (meth) acrylate. Specifically, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, 1-adamantyl (meth) acrylate, methyl (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, lauryl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (Meth) acrylate, benzyl (meth) acrylate, allyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, о-phenylphenol EO modified (n = 1 to 4) (meth) acrylate, p-cumylphenol EO-modified (n = 1-4) (meth) acrylate, phenyl (meth) acrylate, о-phenylphenyl (meth) acrylate, p-cumylphenyl (meth) acrylate, N- (meth) acryloylmorpholine, N-vinylformamide, N- (meth) acryloyloxyethyl hexahydrophthalimide, N- (meth) acryloyloxyethyl tetrahydrophthalimide and the like can be mentioned.

2-1-5. Preferable component (A) In the present invention, the component (A) includes diols having a P-Mn of less than 500 (hereinafter collectively referred to as “diol b”), non-yellowing organic diisocyanate, and hydroxyl group among the components described above. Urethane (meth) acrylate which is a reaction product of contained (meth) acrylate is preferable.
In the component (A), the cured product of the composition is excellent in brittleness and flexibility.
Examples of the diol b include the above-described aliphatic diols having 2 to 12 carbon atoms and alicyclic diols having 2 to 12 carbon atoms.
In this case, the diol b is preferably a polyol having a P-Mn of 60 or more and 400 or less.
Specific examples of the compound include aliphatic diols having 2 to 6 carbon atoms such as 1,4-butanediol, tricyclo [5.2.1.0 ^2,6 ] decandimethanol, and 3,9-bis (1 , 1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane and other alicyclic diols having a plurality of rings are preferable, and the strength of the cured product is excellent. 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (common name; spiroglycol) is particularly preferred.

  As the component (A), as described above, the diol b and a non-yellowing organic diisocyanate are reacted to produce an isocyanate group-containing compound, and the compound (compound A-) which is reacted with a hydroxyl group-containing (meth) acrylate. I), a compound (compound A-II) obtained by reacting diol b, a non-yellowing organic diisocyanate and a hydroxyl group-containing (meth) acrylate at the same time, and the like, and compound AI is preferred because the molecular weight is easily controlled.

The component (A) is a reaction product of a diol having P-Mn of 500 or more (hereinafter collectively referred to as “diol a”), diol b, non-yellowing organic diisocyanate, and hydroxyl group-containing (meth) acrylate. Urethane (meth) acrylate is preferred.
Compared to other urethane (meth) acrylates, the component (A) has a mechanical strength by using a long-chain diol diol a, a short-chain diol diol b, and a non-yellowing type organic diisocyanate. It is excellent and the yellowing degree after the light resistance test is small, and the photoelastic coefficient of the cured product of the composition can be low.
Examples of the diol a include the aforementioned polycarbonate diol and polyester diol, and examples of the diol b include the above-described aliphatic diol having 2 to 12 carbon atoms and alicyclic diol having 2 to 12 carbon atoms.
These diols a and b may be used alone or in combination of two or more.

The ratio of diols a and b is preferably diol a: 0 to 50 mol% and diol b: 50 to 100 mol%, more preferably diol a: 0 to 40 mol% and diol b: 60 to 100 mol%. is there.
Further, when triol is used in combination, the ratio of triol is preferably the sum of diols a and b: 50 to 100 mol% and triol: 0 to 50 mol%, more preferably diol a and / or b: 60. ˜100 mol% and triol: 0 to 40 mol%.

  The production method of the component (A) may be carried out in the same manner as described above using diol a and diol b together, and the preferred production method is also the same as described above.

Particularly preferably, as the hydroxyl group-containing (meth) acrylate in the above, those produced using a caprolactone adduct of a hydroxyl group-containing (meth) acrylate, that is, diol b, non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate Urethane (meth) acrylate which is a reaction product of caprolactone adduct is particularly preferable.
The (A) component makes the cured product of the composition particularly excellent in brittleness and flexibility.

As the caprolactone adduct of hydroxyl group-containing (meth) acrylate, a caprolactone adduct of hydroxyalkyl (meth) acrylate is preferred. Furthermore, the reaction ratio of caprolactone to hydroxyl group-containing (meth) acrylate is preferably greater than 0.1 mol and less than 2.0 mol.
The production method of the component (A) may be carried out in the same manner as described above, and the preferred production method is also the same as described above.

2-2. Other Components The composition used in the present invention preferably contains the component (A), but various components can be blended depending on the purpose.
Hereinafter, other components will be described.
Specifically, a polymer having a photoelastic coefficient of 5 × 10 ⁻¹² Pa ⁻¹ or less (hereinafter referred to as “component (B)”) and a homopolymer other than the component A) have a glass transition temperature of 0 ° C. or higher. Ethylenically unsaturated compound (hereinafter referred to as “component (C)”), ethylenically unsaturated compound other than components (A) and (C) (hereinafter referred to as “component (D)”), photopolymerization initiation Agents (hereinafter referred to as “component (E)”), organic solvents (hereinafter referred to as “component (F)”), plasticizers, polymerization inhibitors or / and antioxidants, light resistance improvers, and the like. .
Hereinafter, these components will be described.

2-2-1. Component (B) The component (B) is a polymer having a photoelastic coefficient of 5 × 10 ⁻¹² Pa ⁻¹ or less.
The cured product of the component (A) usually has a positive photoelastic coefficient in the range of 10 × 10 ⁻¹² to 30 × 10 ⁻¹² Pa ⁻¹ , so that the photoelastic coefficient is 5 × 10 ⁻¹² Pa ⁻¹ or less. By blending with a certain component (B), the photoelastic coefficient of the cured product can be 10 × 10 ⁻¹² Pa ⁻¹ or less.

The photoelastic coefficient of the component (B) is preferably −10 × 10 ^{−12 to} 5 × 10 ⁻¹² Pa ⁻¹ , more preferably −10 × 10 ⁻¹² to 2 × 10 ⁻¹² Pa ⁻¹ . More preferably, it is −10 × 10 ⁻¹² to ⁻² × 10 ⁻¹² Pa ⁻¹ .

  As the component (B), various compounds can be used as long as the polymer has the photoelastic coefficient as described above, and a homopolymer or copolymer of a monomer having a (meth) acryloyl group, N-vinyl-2-pyrrolidone copolymer. Examples thereof include a polymer, a homopolymer or copolymer of α-methylstyrene, and an ethylene-tetracyclododecene copolymer.

  As the monomer having a (meth) acryloyl group, specifically, (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) ) Acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycidyl (meth) acrylate and other (meth) acrylates; 2-hydroxyethyl (meth) ) Acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate and other hydroxyl group-containing (meth) acrylates; N- (meth) acryloylmorpho Acrylamides such as (meth) acrylamide, N-methylol acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and N, N-dimethylaminopropyl (meth) acrylamide Can be mentioned.

As a copolymer of a monomer having a (meth) acryloyl group, a copolymer having an amide structure or a carboxyl group is preferable in that it has a large negative photoelastic coefficient value and is excellent in compatibility with the component (A).
In the copolymer having an amide structure, the amide structure is preferably a morpholine structure. As a specific example of the copolymer having an amide structure, a copolymer of methyl (meth) acrylate and / or t-butyl (meth) acrylate and N- (meth) acryloylmorpholine is preferable.
As a specific example of the copolymer having a carboxyl group, a copolymer of methyl (meth) acrylate and acrylic acid or methacrylic acid is preferable.

A commercially available thing can also be used as a homopolymer or copolymer of the monomer which has a (meth) acryloyl group. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dianal BR52, BR80, BR83, BR85, BR87, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electric Chemical Co., Ltd.), etc. Can be mentioned.
Dianal is a copolymer of monomers having a (meth) acryloyl group, and BR83, BR87 and BR88 are commercially available copolymers having a carboxyl group.

In the N-vinyl-2-pyrrolidone copolymer, examples of the copolymerizable monomer of N-vinyl-2-pyrrolidone include vinyl acetate and alkyl (meth) acrylate.
Specific examples of the N-vinyl-2-pyrrolidone copolymer include vinyl pyrrolidone / vinyl acetate copolymer, vinyl pyrrolidone / methyl (meth) acrylate copolymer, vinyl pyrrolidone / ethyl (meth) acrylate copolymer, vinyl A pyrrolidone butyl (meth) acrylate copolymer etc. can be mentioned.

A commercially available N-vinyl-2-pyrrolidone copolymer can also be used.
For example, PVP / VA S-630 [manufactured by asp Japan Co., Ltd.] and the like can be mentioned.

  The weight average molecular weight (hereinafter referred to as Mw) of the component (B) is preferably 1,000 to 100,000 in terms of excellent compatibility with the component (A).

  There is no restriction | limiting in particular as a manufacturing method of (B) component, Any of well-known methods, such as suspension polymerization, emulsion polymerization, block polymerization, or solution polymerization, may be used using the above-mentioned monomer. . Here, as a polymerization initiator, a normal peroxide type and an azo type can be used, and a redox type can also be used.

  Regarding the polymerization temperature, suspension or emulsion polymerization may be performed at 30 to 100 ° C, and bulk or solution polymerization may be performed at 80 to 300 ° C. Furthermore, although polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent, it is preferable that the amount used is small in order to reduce the photoelastic coefficient.

As the component (B) in the present invention, a polymer having an ethylenically unsaturated group (hereinafter referred to as “(UB) component”) can be used, and the compatibility with the component (A) and the brittleness of the cured product are improved. And since it can increase (B) component content, it is preferable at the point that a photoelastic coefficient can further be reduced.
Hereinafter, the (UB) component will be described.

As the (UB) component (UB) component, various compounds can be used as long as the photoelastic coefficient is 5 × 10 ⁻¹² Pa ⁻¹ or less and the polymer has an ethylenically unsaturated group. Mention may be made of the polymers shown.
1) Polymer B1: Polymer containing carboxyl group (hereinafter referred to as “carboxyl group-containing prepolymer”) and / or polymer containing hydroxyl group (hereinafter referred to as “hydroxyl group-containing prepolymer”), isocyanate group and ethylene Polymer 2 obtained by adding a compound having a polymerizable unsaturated group (hereinafter referred to as “isocyanate-based unsaturated compound”) 2) Polymer B2: Compound having an epoxy group and an ethylenically unsaturated group on a carboxyl group-containing prepolymer Polymer 3 obtained by adding (hereinafter referred to as “epoxy unsaturated compound”) Polymer B3: Polymer containing epoxy group (hereinafter referred to as “epoxy group-containing prepolymer”), carboxyl group and ethylenic property Obtained by adding a compound having an unsaturated group (hereinafter referred to as “carboxyl unsaturated compound”) Polymer

◇ Prepolymer production method The carboxyl group-containing prepolymer used in the production of the polymer B1 and the polymer B2 includes a carboxyl-based unsaturated compound and other ethylenically unsaturated compounds (hereinafter referred to as "other unsaturated compounds"). And a polymer containing a carboxyl group at the terminal obtained by polymerizing another unsaturated compound in the presence of a chain transfer agent having a carboxyl group (hereinafter referred to as a terminal carboxyl group-containing polymer).
Hereinafter, the manufacturing method of a carboxyl group-containing prepolymer, a hydroxyl group-containing prepolymer, and an epoxy group-containing prepolymer will be described.

-Manufacturing method of carboxyl group-containing prepolymer First, the copolymer of a carboxyl type unsaturated compound and other unsaturated compounds is demonstrated.

Examples of carboxyl unsaturated compounds include (meth) acrylic acid, modified polycaprolactone of (meth) acrylic acid, and carboxyl groups such as monohydroxyethyl (meth) acrylate phthalate and monohydroxyethyl (meth) acrylate succinate ( And (meth) acrylate.
Among these, (meth) acrylic acid is preferably used because the photoelastic coefficient of the component (B) obtained is particularly low.

Other unsaturated compounds are not particularly limited as long as the photoelastic coefficient of the component (B) to be obtained is 5 × 10 ⁻¹² Pa ⁻¹ or less, but excellent in copolymerizability with the above-described carboxyl-based unsaturated compound. To (meth) acryloyl group-containing compounds are preferred.
As a compound having a (meth) acryloyl group, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, t-butyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl ( (Meth) acrylates such as (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycidyl (meth) acrylate;
N- (meth) acryloylmorpholine;
Acrylamides such as (meth) acrylamide, N-methylolacrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and N, N-dimethylaminopropyl (meth) acrylamide; and (meth) Examples include acrylonitrile.
If necessary, compounds other than the compound having a (meth) acryloyl group can also be used, and examples thereof include styrene, α-methylstyrene, and vinyl acetate.

  Among these, it is preferable to use methyl (meth) acrylate and N- (meth) acryloylmorpholine because the photoelastic coefficient of the component (B) obtained is particularly low.

The prepolymer may further be a copolymer of a compound having a hydroxyl group and an ethylenically unsaturated group (hereinafter referred to as a “hydroxy unsaturated compound”).
Hydroxyl unsaturated compounds include hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and hydroxyhexyl (meth) acrylate, And hydroxyalkyl vinyl ethers such as hydroxybutyl vinyl ether.

There is no restriction | limiting in particular as a manufacturing method of the copolymer of a carboxyl type unsaturated compound and another unsaturated compound, The same manufacturing method as the said (E) component can be mentioned using an above described compound.
Among these, the solution polymerization method is preferable because the polymer can be easily produced and does not contain extra impurities such as an emulsifier.

Next, the manufacturing method of a terminal carboxyl group containing polymer is demonstrated.
Examples of the method for producing the terminal carboxyl group-containing polymer include a method of polymerizing other unsaturated compounds in the presence of a chain transfer agent having a carboxyl group.
Other unsaturated compounds include the same compounds as described above, and the same compounds as described above are preferable.
Examples of the chain transfer agent having a carboxyl group include 3-mercaptopropionic acid and mercaptoacetic acid.
The ratio of the chain transfer agent having a carboxyl group may be appropriately set according to the ratio of the ethylenically unsaturated group to be finally introduced, and is 0.01 to 100 parts by weight based on the total of 100 parts by weight of all monomers used. 7 parts by weight is preferred.
As the polymerization method, the same method as described above can be employed.

-Production method of hydroxyl group-containing prepolymer The hydroxyl group-containing prepolymer used in the polymer B1 is a copolymer of a hydroxy unsaturated compound and other unsaturated compounds, and other unsaturated compounds in the presence of a chain transfer agent having a hydroxyl group. Examples thereof include a polymer containing a hydroxyl group at the terminal obtained by polymerizing the compound (hereinafter referred to as “terminal hydroxyl group-containing polymer”).

Examples of the hydroxy unsaturated compound include the same compounds as described above.
Other unsaturated compounds include the same compounds as described above, and the same compounds as described above are preferable.

  As a manufacturing method of the copolymer of a hydroxyl-type unsaturated compound and another unsaturated compound, it can manufacture in accordance with the method similar to the above.

Next, the manufacturing method of a terminal hydroxyl group containing polymer is demonstrated.
Examples of the method for producing a terminal hydroxyl group-containing polymer include a method of polymerizing other unsaturated compounds in the presence of a chain transfer agent having a hydroxyl group.
Other unsaturated compounds include the same compounds as described above, and the same compounds as described above are preferable.
Examples of the chain transfer agent having a hydroxyl group include 2-mercaptoethanol.
What is necessary is just to set suitably as a ratio of the chain transfer agent which has a hydroxyl group according to the ratio of the ethylenically unsaturated group finally introduce | transduced, 0.01-7 parts with respect to a total of 100 weight part of all the monomers to be used. Part by weight is preferred.
As the polymerization method, the same method as described above can be employed.

-Manufacturing method of epoxy-group-containing prepolymer As an epoxy-group-containing prepolymer used with polymer B3, the copolymer of an epoxy-type unsaturated compound and another unsaturated compound is mentioned.

Examples of the epoxy unsaturated compound include epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and cyclohexene oxide-containing (meth) acrylate.
Other unsaturated compounds include the same compounds as described above, and the same compounds as described above are preferable.

  As a manufacturing method of the copolymer of an epoxy unsaturated compound and other unsaturated compounds, it can manufacture according to the method similar to the above.

-Manufacturing method of (UB) component (UB) component has the functional group and ethylenically unsaturated group which can react with these prepolymer with respect to a carboxyl group-containing prepolymer, a hydroxyl group-containing prepolymer, and an epoxy group-containing prepolymer. It is introduced by addition reaction of the compound.
The addition reaction may be carried out in accordance with a conventional method, and it can be produced in an organic solvent or without a solvent. As conditions for the addition reaction, the reaction temperature, reaction time, and catalyst may be appropriately selected according to each reaction.

○ Ratio of component (B) As the component (B), only one kind of the aforementioned compounds may be used, or two or more kinds may be used in combination.
The proportion of the component (B) may be appropriately set according to the purpose, but the component (A) is 30 to 99% by weight based on the total amount of the component (B) and the component (B), and the component 1 (B). -70 weight% is preferable, More preferably, (A) component 40-90 weight% and (B) component 10-60 weight%.
By making the ratio of the component (A) 30% by weight or more, the cured product obtained can be excellent in mechanical properties, and by making it 99% by weight or less, the photoelastic coefficient is further reduced. Can do.

2-2-2. Component (C) Component (C) is an ethylenically unsaturated compound having a homopolymer glass transition temperature of 0 ° C. or higher.
In the component (C), examples of the ethylenically unsaturated group include a (meth) acryloyl group, a vinyl group, a vinyl ether group, and the like, and a (meth) acryloyl group is preferable.

As the component (C), various compounds can be used as long as they have an ethylenically unsaturated group and the homopolymer has a Tg of 0 ° C. or higher. A compound having one (meth) acryloyl group (hereinafter referred to as “component”) , “Monofunctional (meth) acrylate”), compounds having two or more (meth) acryloyl groups (hereinafter referred to as “polyfunctional (meth) acrylate”), (meth) acrylamide compounds, fumaric acid esters, malees Examples include acid esters, allyl compounds, and vinyl compounds.
Monofunctional (meth) acrylates include methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl (meth) acrylate, pentyl methacrylate, isopentyl methacrylate, neopentyl (meth) acrylate, cyclohexyl (Meth) acrylate, isobornyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and the like.
As polyfunctional (meth) acrylates, alkylene glycol di (meth) such as ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate and tripropylene glycol di (meth) acrylate Acrylate;
Glycol di (meth) acrylates such as 1,6-hexanediol di (meth) acrylate and neopentyl glycol di (meth) acrylate;
Dimethylol tricyclodecane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa ( Polyol poly (meth) acrylates such as (meth) acrylate;
Examples include poly (meth) acrylates of alkylene oxide adducts of polyols; and di- or tri (meth) acrylates of isocyanuric acid alkylene oxides.
Examples of the (meth) acrylamide compound include N- (meth) acryloylmorpholine, N, N-dimethyl (meth) acrylamide, N-isopropylacrylamide, and N, N-dimethylaminopropyl (meth) acrylamide.
Examples of the fumaric acid ester include dimethyl fumarate, diethyl fumarate, diisopropyl fumarate and dibutyl fumarate.
Examples of allyl compounds include glycerin monoallyl ether, trimethylolpropane diallyl ether, pentaerythritol triallyl ether, and isocyanuric acid triallyl.
Examples of the vinyl compound include N-vinylpyrrolidone, 4-vinylcyclohexene, vinyl acetate and the like.

As the component (C), among the above-described compounds, compounds having tertiary and quaternary carbon atoms are preferable because they have a low photoelastic coefficient.
Here, the tertiary carbon atom is a carbon atom in which one hydrogen atom and three atoms other than a hydrogen atom are bonded, and the quaternary carbon atom is a carbon atom in which four atoms other than a hydrogen atom are bonded. Means.
Specific examples of the compound include monofunctional (meth) acrylates such as isopropyl methacrylate, isobutyl methacrylate, t-butyl (meth) acrylate, isopentyl methacrylate, neopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) ) Acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, 1-adamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and the like. Polyfunctional (meth) acrylates include neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate; poly (meth) acrylate of an alkylene oxide adduct of the above polyol; and di- or tri (meth) acrylate of isocyanuric acid alkylene oxide, etc. Is mentioned.
Examples of the (meth) acrylamide compound include N-isopropylacrylamide.
Examples of the fumaric acid ester include diisopropyl fumarate and dibutyl fumarate.
Examples of maleic acid esters include diisopropyl malate.
4-vinylcyclohexene is mentioned as a vinyl compound.

  Furthermore, among these, in particular, isobutyl methacrylate (Tg of homopolymer: 67 ° C.), t-butyl (meth) acrylate (Tg of homopolymer of acrylate: 41 ° C., Tg of homopolymer of methacrylate: 107 ° C., hereinafter parentheses , 3,3,5-trimethylcyclohexyl (meth) acrylate (acrylate homopolymer Tg: 81 ° C.) and isobornyl (meth) acrylate (acrylate homopolymer Tg: 94 ° C., methacrylate) (Tg: 180 ° C.) is more preferable in terms of good mechanical properties and less coloration after heat treatment.

As the component (C), among the compounds described above, a compound having an aliphatic cyclic skeleton or a compound having a saturated cyclic skeleton containing a hetero atom is preferable because it has a low photoelastic coefficient.
Specific examples of the compound include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 3,3,5-trimethylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. Monofunctional (meth) acrylate having an aliphatic cyclic skeleton; polyfunctional (meta) having an aliphatic cyclic skeleton such as dimethylol tricyclodecane di (meth) acrylate and poly (meth) acrylate of an alkylene oxide adduct of the polyol. ) Acrylate; 2-propionic acid (5-ethyl-1,3-dioxane-5-yl) methyl ester and 2-methyl-2-propionic acid (5-ethyl-1,3-dioxane-5-yl) methyl ester Having a saturated cyclic skeleton containing oxygen atoms such as No monofunctional (meth) acrylate: and N- (meth) acrylate saturated cyclic skeleton monofunctional containing a (meth) acrylate containing a nitrogen atom such as acryloyl morpholine.

  Among these, in particular, 2-propionic acid (5-ethyl-1,3-dioxane-5-yl) methyl ester (Tg of homopolymer: 10 ° C.), 3,3,5-trimethylcyclohexyl (meth) acrylate (Tg of acrylate homopolymer: 81 ° C.), isobornyl (meth) acrylate (Tg of acrylate homopolymer: 94 ° C., Tg of homopolymer of methacrylate: 180 ° C.) and N- (meth) acryloylmorpholine (acrylate homo Polymer Tg: 145 ° C.) is more preferable in terms of good mechanical properties.

  As the component (C), only one kind of the aforementioned compounds may be used, or two or more kinds may be used in combination.

  The proportion of the component (A) and the component (C) may be appropriately set according to the purpose, but the amount of the component (A) is 30 to 90% by weight based on the total amount of the component (A) and the component (C), and 70 to 10 weight% of (C) component is preferable, More preferably, it is 50 to 80 weight% of (A) component and 50 to 20 weight% of (C) component.

2-2-3. Component (D) Component (D) is an ethylenically unsaturated compound other than components (A) and (C).
(D) A component is a component mix | blended as needed for the purpose of reducing the viscosity of the whole composition and adjusting the other physical properties.

  Specific examples of the component (D) include (meth) acrylates other than the components (A) and (C) [hereinafter referred to as “other (meth) acrylates”], N-vinyl-2-pyrrolidone, and the like.

  Other (meth) acrylates include a compound having one (meth) acryloyl group (hereinafter referred to as “monofunctional (meth) acrylate”) and a compound having two or more (meth) acryloyl groups [hereinafter referred to as “multiple”. Functional (meth) acrylate ”and the like.

  Specific examples of the monofunctional (meth) acrylate include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl ( (Meth) acrylate, diethylaminoethyl (meth) acrylate, benzyl (meth) acrylate, allyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, о-phenylphenol EO modification (n = 1 to 1) 4) (meth) acrylate, p-cumylphenol EO modified (n = 1 to 4) (meth) acrylate, phenyl (meth) acrylate, о-phenylphenyl (meth) acrylate, p-cumylphenyl (meth) a Examples thereof include acrylate, N-vinylformamide, N- (meth) acryloyloxyethyl hexahydrophthalimide, N- (meth) acryloyloxyethyl tetrahydrophthalimide and the like.

Specific examples of the polyfunctional (meth) acrylate include bisphenol A EO-modified (n = 1 to 2) di (meth) acrylate, bisphenol A di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene glycol di (meth). ) Acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (n = 5-14) di (meth) acrylate, dipropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol (n = 5-14) Di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polybutylene glycol (n = 3-16) di (meth) acrylate, Po Li (1-methylbutylene glycol) (n = 5 to 20) di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, spiroglycol di (meth) ) Bifunctional (meth) acrylate of acrylate.
In the above, EO modification means ethylene oxide modification, and n means the number of repeating alkylene oxide units.

  As the component (D), only one of the aforementioned compounds may be used, or two or more may be used in combination.

  The proportion of the component (D) may be appropriately set according to the purpose, and may be an amount that does not decrease the flexibility of the resulting cured product, but the total amount of the component (A) is 100 parts by weight. When (B) component and (C) component are included, 1 to 100 weight% is preferable with respect to 100 weight part of total amounts of (A) component, (B) component, and (C) component, More preferably 1 to 80% by weight.

2-2-4. (E) component (E) component is a photoinitiator.
(E) A component is a component mix | blended when an ultraviolet-ray and visible light are used as an active energy ray. When an electron beam is used as the active energy ray, it is not always necessary to add it, but a small amount can be added as necessary in order to improve curability.

(E) Component includes benzyl dimethyl ketal, benzyl, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, oligo [2-hydroxy-2-methyl-1- [4-1- (methylvinyl) phenyl] Propanone, 2-hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl] -2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) )] Phenyl] -2-morpholinopropan-1-one, 2- Nediru 2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) -butane-1 -Aromatic ketone compounds such as ON, Adekaoptomer N-1414 (manufactured by ADEKA), phenylglyoxylic acid methyl ester, ethyl anthraquinone, phenanthrenequinone;
Benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 4- (methylphenylthio) phenylphenylmethane, methyl-2-benzophenone, 1- [4- (4-Benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfonyl) propan-1-one, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis ( Benzophenone compounds such as diethylamino) benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, N, N′-tetraethyl-4,4′-diaminobenzophenone and 4-methoxy-4′-dimethylaminobenzophenone ;
Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl- (2,4,6-trimethylbenzoyl) phenylphosphinate and bis (2, Acylphosphine oxide compounds such as 6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide;
Thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propylthioxanthone, 3- [3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl] oxy]- Thioxanthone compounds such as 2-hydroxypropyl-N, N, N-trimethylammonium chloride and fluorothioxanthone;
Acridone compounds such as acridone, 10-butyl-2-chloroacridone;
1,2-octanedione 1- [4- (phenylthio) -2- (O-benzoyloxime)] and ethanone 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] Oxime esters such as -1- (O-acetyloxime);
2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-phenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2 2,4,5-triarylimidazole such as 2,4-di (p-methoxyphenyl) -5-phenylimidazole dimer and 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole dimer Dimer; and acridine derivatives such as 9-phenylacridine and 1,7-bis (9,9'-acridinyl) heptane.

  These compounds may be used alone or in combination of two or more.

(E) As a compounding ratio of a component, when it contains the said (B) component, (C) component, and (D) component with respect to a total of 100 weight part of (A) component, (A) component, ( The content is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on 100 parts by weight of the total amount of the component B), the component (C) and the component (D).
By setting the blending ratio of the component (E) to 0.01% by weight or more, the composition can be cured with an appropriate amount of ultraviolet light or visible light, and the productivity can be improved. By doing, it can be made the thing excellent in the weather resistance and transparency of hardened | cured material.

2-2-5. Component (F) The composition of the present invention preferably contains an organic solvent as the component (F) for the purpose of improving the coating property to the substrate.

Specific examples of the component (F) include hydrocarbon solvents such as n-hexane, benzene, toluene, xylene, ethylbenzene, and cyclohexane;
Methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 2-butoxy Ethanol, 2-isopentyloxyethanol, 2-hexyloxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 1 -Methoxy-2-propanol, 1-ethoxy-2-propanol and propylene glycol monomethyl Alcohol solvents such as ether;
Ether solvents such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether and bis (2-butoxyethyl) ether;
Acetone, methyl ethyl ketone, methyl-n-propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, methyl pentyl ketone, di-n-propyl ketone, diisobutyl ketone, phorone, isophorone, cyclopentanone, cyclohexanone, methylcyclohexanone, etc. Ketone solvents;
Ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, methyl glycol acetate, propylene glycol monomethyl ether acetate, cellosolve acetate;
Examples include aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and γ-butyrolactone.

As the component (F), one or more of the aforementioned compounds can be used.
As an organic solvent, you may add separately and may use it as it is, without isolate | separating the organic solvent used by urethane (meth) acrylate manufacture.

  In the case of coating directly on the polarizer, one that does not dissolve the polarizer is used in order to maintain the optical function, but a hydrocarbon solvent such as toluene or an ester solvent such as ethyl acetate is preferable.

  The proportion of the component (F) may be set as appropriate, but is preferably 10 to 90% by weight, more preferably 40 to 80% by weight in the composition.

2-2-6. For the purpose of imparting flexibility to the cured plasticizer and improving brittleness, a plasticizer can be added. Specific examples of the plasticizer include dialkyl phthalates such as dioctyl phthalate and diisononyl phthalate, dialkyl esters of adipic acid such as dioctyl adipate, phosphate esters such as sebacic acid ester, azelaic acid ester and tricresyl phosphate, polypropylene Examples thereof include liquid polyether polyols such as glycol, liquid polyester polyols such as polycaprolactone diol and 3-methylpentanediol adipate.
The blending ratio of these plasticizers may be set as appropriate. When the component (B) and the component (C) are included with respect to 100 parts by weight of the component (A), the component (A), 5-30 weight% is preferable with respect to 100 weight part of total amounts of (B) component and (C) component, More preferably, it is 5-20 weight%.
When the blending ratio of the plasticizer is 5% by weight or more, flexibility is exhibited, and when it is 30% by weight or less, toughness is maintained.

2-2-7. Polymerization inhibitor or / and antioxidant It is preferable to add a polymerization inhibitor or / and an antioxidant to the composition of the present invention because the storage stability of the composition of the present invention can be improved.
As the polymerization inhibitor, hydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, and various phenolic antioxidants are preferable. A secondary antioxidant or the like can also be added.
When the total blending ratio of these polymerization inhibitors or / and antioxidants includes the component (B) and the component (C) with respect to a total of 100 parts by weight of the component (A), the component (A), It is preferable that it is 0.001 to 3 weight% with respect to 100 weight part of total amounts of (B) component and (C) component, More preferably, it is 0.01 to 0.5 weight%.

2-2-8. The composition of the light resistance improver present invention, the light resistance improving agent such as an ultraviolet absorber or a light stabilizer may be added.
Examples of the ultraviolet absorber include 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2- (2 Benzotriazole compounds such as'-hydroxy-3'-t-butyl-5'-methylphenyl)benzotriazole;
Triazine compounds such as 2,4-bis (2,4-dimethylphenyl) -6- (2-hydroxy-4-iso-octyloxyphenyl) -s-triazine;
2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2, 4, 4 ' -Trihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3', 4,4'-tetrahydroxybenzophenone, or 2,2 Examples include benzophenone compounds such as'-dihydroxy-4,4'-dimethoxybenzophenone.
Examples of the light stabilizer include N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2,6,6). -) Pentamethyl-4-piperidyl) -2- (3,5-ditertiarybutyl-4-hydroxybenzyl) -2-n-butylmalonate, bis (1,2,2,6,6-pentamethyl-4- Low molecular weight hindered amine compounds such as piperidinyl) sebacate; N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) -N, N′-diformylhexamethylenediamine, bis (1,2 Hindered amine light stabilizers such as high molecular weight hindered amine compounds such as 2,6,6-pentamethyl-4-piperidinyl) sebacate.
The blending ratio of the light fastness improver includes the component (A), the component (B) when the component (B), the component (C), and the component (D) are included with respect to 100 parts by weight of the component (A). ) Component, (C) component, and (D) component is preferably 0 to 5% by weight, more preferably 0 to 1% by weight, based on 100 parts by weight of the total amount.

3. Polarizer invention, on at least one surface of the polarizer, the film-like cured product of an active energy ray-curable composition described above as a protective film is a polarizing plate which is formed directly.
When the cured product of the composition is directly formed on at least one surface of the polarizer, it is possible to reduce the amount of foreign matter mixed in and to reduce the thickness of the polarizing plate as compared with bonding using an adhesive or the like.

  As a configuration of the polarizing plate, various forms can be adopted as long as a cured product of the composition is formed on at least one surface of the polarizer.

As an example of a polarizing plate, the polarizing plate of the following structure etc. which formed one layer of the hardened | cured material of the composition on the single side | surface of a polarizer are mentioned.
Hardened | cured material / polarizer In addition to this, the polarizing plate of the following structure etc. which formed two layers of the hardened | cured material of the composition on both surfaces of the polarizer are mentioned.
Cured product / polarizer / cured product

As an example of another polarizing plate, a polarizing plate having the following constitution and the like having a base material on which one layer of a cured product is laminated on one side of a polarizer and the cured product can be peeled off.
Polarizer / cured product / peelable substrate In addition to this, two layers of the cured product of the composition are formed on both sides of the polarizer, and each cured product has a peelable substrate as described below. A polarizing plate etc. are mentioned.
Peelable substrate / cured product / polarizer / cured product / peelable substrate

Examples of the peelable substrate include a release-treated film and a surface untreated film having peelability (hereinafter collectively referred to as “release material”).
Examples of the release material include silicone-treated polyethylene terephthalate film, surface untreated polyethylene terephthalate film, surface untreated cycloolefin polymer film, and surface untreated OPP film (polypropylene).
In order to suppress the haze of the cured product of the composition of the present invention to 1.0% or less, it is preferable to use a surface untreated polyethylene terephthalate film or a surface untreated OPP film (polypropylene).

In order to give a low haze or impart surface smoothness to the polarizer protective film obtained from the composition of the present invention, a substrate having a surface roughness Ra of 150 nm or less should be used as a peelable substrate. Is preferred.
Specific examples of the substrate include a surface untreated polyethylene terephthalate film and a surface untreated OPP film (polypropylene).
In the present invention, the surface roughness Ra means a value obtained by measuring the surface roughness of the film and calculating an average roughness.

4). Hereinafter, a method for producing a polarizing plate of the present invention will be described.
In the following, a part of the description will be given with reference to FIGS.

As a manufacturing method of a polarizing plate, various usage methods can be employ | adopted according to the objective of polarizer protective film formation.
Specifically, the composition is directly applied to the polarizer and irradiated with an active energy ray to cure, and the active energy ray is further applied after the composition is applied to a peelable substrate and bonded to the polarizer. The method of irradiating and hardening and peeling a base material etc. is mentioned.

In coating the composition, the composition of the resulting optical film is stirred and mixed in order to prevent the introduction of foreign substances, the occurrence of defects such as voids, and the excellent optical properties. After that, it is preferable to use a purified product.
As a method for purifying the composition, a method of filtering the composition is simple and preferable. Examples of the filtration method include pressure filtration.
The filtration accuracy is preferably 10 μm or less, more preferably 5 μm or less. The lower the filtration accuracy, the better. However, if the filter accuracy is too small, the filter is likely to be clogged, and the filter replacement frequency increases and the productivity is lowered. Therefore, the lower limit is preferably 0.1 μm.

  The coating method may be appropriately set according to the purpose, and conventionally known bar coat, applicator, doctor blade, knife coater, comma coater, reverse roll coater, die coater, lip coater, gravure coater, micro gravure coater, etc. The method of coating with is mentioned.

Examples of the active energy rays include ultraviolet rays, visible rays, and electron beams. Among these, ultraviolet rays are more preferable in that they have been used in polarizing plate lines, and an electron beam is more preferable in terms of excellent heat resistance and light resistance of a cured product without necessarily including a photopolymerization initiator.
What is necessary is just to set suitably irradiation conditions, such as irradiation intensity | strength and a dose in active energy ray irradiation, according to the composition to be used, a base material, a purpose, etc.

FIG. 1 shows an example of a preferred method for producing a polarizing plate comprising a polarizer / cured product.
In FIG. 1, (1) means a polarizer.
When the composition is a solventless type (FIG. 1: F1), the composition is applied to a polarizer [FIG. 1: (1)]. When the composition contains an organic solvent or the like (FIG. 1: F2), the composition is applied to a polarizer [FIG. 1: (1)] and then dried to evaporate the organic solvent (FIG. 1: 1). -1).
A polarizing plate composed of a polarizer / cured product is obtained by irradiating active energy rays to a sheet having the composition layer (2) formed on the polarizer. The active energy ray is usually irradiated from the composition layer side, but can also be irradiated from the polarizer side.

  The coating amount of the composition of the present invention may be appropriately selected according to the application to be used, but it is preferable to coat so that the film thickness after drying the organic solvent or the like is 5 to 100 μm. Preferably it is 10-40 micrometers.

When the composition contains an organic solvent or the like, it is heated and dried after coating to evaporate the organic solvent or the like.
As a heating / drying method, a method of passing through a furnace equipped with a heating device, or it can be carried out by blowing air,
The heating / drying conditions may be appropriately set according to the organic solvent used, and examples thereof include a method of heating to a temperature of 40 to 150 ° C.
When applying directly to a polarizer, the method of heating to the temperature below 80 degreeC which a polarizer does not heat-shrink is preferable.
As the composition after heating and drying, the proportion of the organic solvent is preferably 1% by weight or less.

  What is necessary is just to set suitably irradiation conditions, such as irradiation intensity | strength and a dose in active energy ray irradiation, according to the composition to be used, a base material, etc.

  FIG. 2 shows an example of a preferred method for producing a polarizing plate comprising a polarizer / cured product / release material.

In FIG. 2, (1) means a release material, and (3) means a polarizer.
When the composition is a solventless type (FIG. 2: F1), the composition is applied to a release material [FIG. 2: (1)]. When the composition contains an organic solvent or the like (FIG. 2: F2), the composition is applied to a release material [FIG. 2: (1)] and then dried to evaporate the organic solvent (FIG. 2: 2). -1).
By irradiating active energy rays after laminating the polarizer (3) on the sheet having the composition layer (2) formed on the release material, the release material, the cured product, and the polarizer are formed in this order. A polarizing plate is obtained, and the release material is peeled off in use.

4-2. Use of polarizing plate The polarizing plate of the present invention can be used for various optical uses. More specifically, a polarizing plate used for a liquid crystal display device, an organic EL display device, a touch panel integrated liquid crystal display device, a touch panel integrated organic EL display device, or the like can be given.

When using a polarizing plate, it can also be set as the optical member which provided the optical layer which shows optical functions other than a polarizing function through the protective film layer which comprises this invention.
Examples of the optical layer laminated on the polarizing plate for the purpose of forming an optical member include those used for forming a liquid crystal display device, such as a retardation plate and a brightness enhancement film.

  The retardation plate as the optical layer described above is used for the purpose of compensation of retardation by a liquid crystal cell. Examples thereof include birefringent films made of stretched films of various plastics, films in which discotic liquid crystals and nematic liquid crystals are oriented and fixed, and films in which the liquid crystal layer is formed on a film substrate. In this case, a cellulose-based film such as triacetyl cellulose is preferably used as the film substrate that supports the aligned liquid crystal layer.

Examples of the plastic forming the birefringent film include polycycloolefins such as polynorbornene, cellulosic films such as triacetyl cellulose, polycarbonate, polystyrene, polymethyl methacrylate, polyarylate, and polyamide.
The stretched film may be processed by an appropriate method such as uniaxial or biaxial. Moreover, the birefringent film which controlled the refractive index of the thickness direction of a film by applying a shrinkage force and / or extending | stretching force under adhesion | attachment with a heat-shrinkable film may be sufficient.
Note that two or more retardation plates may be used in combination for the purpose of controlling optical characteristics such as broadening the bandwidth.

  The brightness enhancement film is used for the purpose of improving the brightness in a liquid crystal display device or the like. For example, a plurality of thin film films having different refractive index anisotropies are laminated to produce anisotropy in reflectance. And a reflection-type polarization separation sheet designed in the above, a cholesteric liquid crystal polymer alignment film, and a circular polarization separation sheet in which the alignment liquid crystal layer is supported on a film substrate.

  The optical member is a combination of a polarizing plate and one or two or more optical layers selected according to the purpose of use from the retardation plate, the brightness enhancement film, etc., and a laminate of two or three layers or more. can do.

  The various optical layers forming the optical member are integrated using an adhesive, but the adhesive used for this purpose is not particularly limited as long as the adhesive layer is well formed.

Specific examples of the adhesive include solvent-based adhesives (pressure-sensitive adhesives), solvent-based adhesives, hot-melt adhesives, and solvent-free adhesives. Solvent-free active energy rays A curable adhesive can be suitably used.
Examples of the active energy ray curable adhesive include a photo cation curable adhesive, a photo radical curable adhesive, and a hybrid adhesive that uses both photo cation curing and photo radical curing.
Examples of the photo cation curable adhesive include photo cation curable compounds such as epoxy compounds and oxetane compounds, and adhesives including a photo cation polymerization initiator.
Examples of the photo-radical curable adhesive include photo-radical curable compounds such as (meth) acrylates, vinyl ethers and vinyl compounds, and adhesives containing a photo-radical polymerization initiator.
Examples of the hybrid adhesive include an adhesive containing the above-described photocationic curable compound, photoradical curable compound, photocationic polymerization initiator, and photoradical polymerization initiator.

When having a protective film on both surfaces of a polarizer, the one having the protective film of the present invention on both surfaces is most preferable. However, if necessary, the protective film of the present invention can be used on one side, and a protective film other than the protective film of the present invention (hereinafter referred to as “other protective film”) can be used on the other side.
Examples of other protective films include cellulose acetate resin films such as triacetyl cellulose and diacetyl cellulose, acrylic resin films, polyester resin films, and cyclic polyolefin resin films containing cyclic olefins such as norbornene as monomers. Moreover, when using these as a protective film of a display side, the film which has phase difference may be sufficient.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” means parts by weight.

○ Production Example 1 [Production of component (A)]
In a 500 mL reaction vessel equipped with a stirrer, a thermometer, and a cooler, IPDI: 151.4 g as an isocyanate and 0.07 g of dibutyltin dilaurate as a catalyst were charged at room temperature, and these were placed in a nitrogen atmosphere containing 5% by volume of oxygen. While stirring, the liquid temperature was increased to 70 ° C.
1,4-butanediol (hydroxyl value: 1247 mg KOH / g, P-Mn: 90): 28.2 g as an alcohol solution, polycaprolactone triol (hydroxyl value: 544 mg KOH / g, P-Mn: 309) [Daicel Plaxel 303 manufactured by Co., Ltd., number average molecular weight 300]: 18.3 g, polycarbonate diol (hydroxyl value: 108 mg KOH / g, P-Mn: 1040) [Duranol T-5651 manufactured by Asahi Kasei Chemicals Corporation]: 20.4 g Methyl ethyl ketone (hereinafter referred to as “MEK”): 65.0 g of a mixed solution was added dropwise so that the internal temperature was 75 ° C. or lower, and then reacted at an internal temperature of 80 ° C. for 2 hours.
Thereafter, 2-hydroxyethyl acrylate (hereinafter referred to as “HEA”): 61.6 g as a hydroxyl group-containing acrylate, and 2,6-di-t-butyl-4-methylphenol (hereinafter referred to as “BHT”) as a polymerization inhibitor. ): 0.28 g, MEK: 5.0 g, and dibutyltin dilaurate: 0.07 g of a mixed solution was added dropwise so that the internal temperature would be 75 ° C. or less, followed by reaction for 3 hours. The spectrum was measured by IR Spectrum 100), it was confirmed that the isocyanate group was completely consumed, and a MEK solution (solid content 80%) containing urethane acrylate (hereinafter referred to as “UA-1”) was obtained.
It was 2,400 as a result of measuring the polystyrene conversion weight average molecular weight (henceforth Mw) of UA-1 by GPC (solvent: tetrahydrofuran, column: HSPgel HR MB-L made from Waters).

○ Production Example 2 [Production of Component (A)]
In Production Example 1, a mixed solution of IPDI: 99.6 g and MEK: 50.0 g as isocyanate, spiroglycol as alcohol (hydroxyl value: 369 mg KOH / g, P-Mn: 304) [SPG manufactured by Mitsubishi Gas Chemical Co., Ltd.] : 74.4 g and MEK (used for washing adhered to the reaction vessel after adding SPG powder): 25.5 g, ε-caprolactone 1 mol adduct of 2-hydroxyethyl acrylate as hydroxyl group-containing acrylate [(stock ) FA1DDM manufactured by Daicel]: The same operation was performed except that the mixed solution was 95.6 g and MEK: 5.0 g, and a MEK solution containing urethane acrylate (hereinafter referred to as “UA-2”) (solid content: 80%) Got.
Mw of the obtained UA-2 was 2,300.

○ Production Example 3 [ Production of Component (A) and Component (C)]
In Production Example 1, IPDI: 116.3 g as isocyanate and IBXA [isobornyl acrylate, light acrylate IB-XA manufactured by Kyoeisha Chemical Co., Ltd.]: 177.3 g, SPG as alcohol: 100.3 g and IBXA: 32.5 g The IBXA solution containing urethane acrylate (hereinafter referred to as “UA-3”) (UA concentration: 55%) except that a mixed solution of HEA: 45.9 g and IBXA: 5.0 g was used as the hydroxyl-containing acrylate. )
Mw of the obtained UA-3 was 2,300.

○ Production Example 4 [ Production of (A) Component and (C) Component Mixture]
In Production Example 1, IPDI: 103.8 g as isocyanate and DCPA [dimethylol-tricyclodecane diacrylate, light acrylate DCP-A manufactured by Kyoeisha Chemical Co., Ltd.]: 50.0 g, SPG as alcohol: 93.4 g and Duranol T -5651: 35.4 g, the same operation was performed except that a mixed solution of HEA: 29.9 g and DCPA: 15.6 g as a hydroxyl group-containing acrylate, and urethane acrylate (hereinafter referred to as “UA-4”) was included. A DCPA solution (UA concentration 80%) was obtained.
Mw of UA-4 obtained was 5,000.

○ Production Example 5 [ Production of urethane acrylate other than component (A)]
In Production Example 1, the same operation was carried out except that IPDI: 151.7 g as isocyanate, Duranol T5651: 78.8 g as the alcohol solution, and HEA: 49.4 g as the hydroxyl group-containing acrylate, and urethane acrylate (hereinafter referred to as “UA”). MEK solution (80% solid content) was obtained.
Mw of the obtained UA-5 was 4,400.

○ Production Example 6 [Production of Component (B)]
In a 500 mL reaction vessel equipped with a stirrer, a thermometer, and a condenser, methyl methacrylate (hereinafter referred to as “MMA”): 7.0 g, N-acryloylmorpholine (hereinafter referred to as “ACMO”): 3.0 g, MEK: 78.0 g was charged and uniformly dissolved at room temperature.
While stirring the contents of the flask, the internal temperature was raised to 80 ° C. under a nitrogen atmosphere. After the internal temperature became constant, MMA: 63.0 g was consumed for 4 hours and ACMO: 27.0 g was applied for 3 hours. On the other hand, a polymerization initiator solution consisting of V-65 [2,2′-azobis-2,4-dimethylvaleronitrile, manufactured by Wako Pure Chemical Industries, Ltd.]: 9.0 g and MEK: 22.5 g Each was continuously fed over 5 hours.
As a result of aging for 4 hours while maintaining the internal temperature at 80 ° C. after completion of continuous supply, a solution (solid content 52%) containing a polymer having a negative photoelastic coefficient (hereinafter referred to as “LP-1”) was obtained. It was.
The obtained LP-1 had Mw of 6,600 and Mn of 2,000.

○ Production Example 7 [ Production of Polarizer]
A polyvinyl alcohol film having a thickness of 80 μm was swelled in a 30 ° C. water bath and then dyed in an aqueous iodine solution of 5 wt% (weight ratio: iodine / potassium iodide = 1/10). Then, it is immersed in an aqueous solution containing 3% by weight boric acid and 2% by weight potassium iodide, and further 5.5 times in an aqueous solution containing 4% by weight boric acid and 3% by weight potassium iodide at 55 ° C. After uniaxial stretching, it was immersed in a 5 wt% potassium iodide aqueous solution. Then, it dried for 1 minute in 70 degreeC oven, and obtained the 30-micrometer-thick polarizer (henceforth polarizer P).
About the obtained polarizer P, when the polarization degree and the single transmittance were measured using the spectrophotometer with a polarizing prism (Shimadzu Corporation UV-2200), it was 99.99% and 43.1%, respectively. there were.

(1) Production Examples C1 to C6, Comparative Production Examples C1 and C2 (Production of Composition)
The components shown in Table 1 below were charged in a stainless steel container at the ratio shown in Table 1, and stirred with a magnetic stirrer while heating to obtain a composition.

The abbreviations in Table 1 mean the following.
LP-2: One-end methacryloyl group polymethyl methacrylate macromonomer, AA-6 manufactured by Toagosei Co., Ltd. [solid content 100%, Mn 6,000]
Dc1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one, DAROCUR-1173 manufactured by BASF Japan

(2) Production Examples C1 to C6, Comparative Production Examples C1 and C2 (measurement of photoelastic coefficient)
To Production Co. C1 to C6 and Comparative Production Examples C1 to 300 mm wide × 300 mm long “Lumirror 50-T60” (surface untreated polyethylene terephthalate film, thickness 50 μm, hereinafter referred to as “Lumirror”) The ultraviolet curable composition obtained in C2 was applied with an applicator so that the film thickness after drying at 60 ° C. for 10 minutes was as shown in Table 2 (Production Examples C5 and C6 had no drying step).
After that, the composition layer was coated with a conveyor type ultraviolet irradiation device (high pressure mercury lamp, lamp height 20 cm, 365 nm irradiation intensity 260 mW / cm ² (Fusion UV Systems Japan Co., Ltd. UV POWER). The conveyor speed was adjusted according to the measurement value of PUCK)), and an ultraviolet ray was irradiated with an integrated light amount of 380 mJ / cm ² to obtain an optical film.
After curing, it was peeled off from Lumirror and used for measurement of photoelastic coefficient. The results are shown in Table 2.

[Photoelastic coefficient]
The optical film obtained above was cut into 15 mm × 60 mm, and the five-point tension σ was changed in the range of 0N to 10N at room temperature using an automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments). The in-plane retardation value at that time was measured, and the photoelastic coefficient was obtained from the slope of the approximate straight line prepared according to the following formula. The results are shown in Table 2.
Δn = C · σ [wherein, Δn represents stress birefringence, σ represents tension, and C represents a photoelastic coefficient. ]

(3) Examples 1 to 7 and Comparative Examples 1 to 2 (Production of Polarizing Plate)
Using the compositions obtained in Production Examples C1 to C7 and Comparative Production Examples C1 to C2 as the polarizer protective film, the film thickness after drying at 60 ° C. for 10 minutes on one side of the polarizer P is described in Table 2. (Examples 6 and 7 were not dried). Thereafter, a conveyor type ultraviolet irradiation device manufactured by Eye Graphics Co., Ltd. (high pressure mercury lamp, lamp height 15 cm, irradiation intensity of 365 nm 370 mW / cm ² (measured value of UV POWER PUCK manufactured by Fusion UV Systems Japan Co., Ltd.)) By adjusting the conveyor speed, ultraviolet irradiation with an integrated light amount of 220 mJ / cm ² was performed.
Further, a polarizer protective film was formed in the same manner on the other surface of the polarizer P to obtain a polarizing plate (width 100 mm × length 100 mm).
In addition, the corona treatment was performed on any surface of the polarizer.

(Measurement of degree of polarization and single transmittance)
About the polarizing plate obtained by the Example and the comparative example, the polarization degree and the single-piece | unit transmittance were measured using the spectrophotometer with a polarizing prism (Shimadzu Corporation UV-2200). The results are shown in Table 2.

[Moisture and heat resistance of polarizing plate: Appearance]
The external appearance of the sample after leaving the polarizing plate obtained by the Example and the comparative example for 120 hours in a 60 degreeC90% RH constant temperature and humidity chamber was visually evaluated on the following references | standards. The results are shown in Table 3.
○: Deformation is not seen.
X: Deformation was observed.

[Moisture and heat resistance of polarizing plate: Iodine decolorization]
The samples obtained in Examples and Comparative Examples were visually evaluated according to the following criteria for the presence or absence of iodine decolorization of samples after being left in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 120 hours. The results are shown in Table 2.
○: Iodine decolorization is not observed.
X: Iodine decolorization was seen.

Examples 1 to 7 are polarizing plates using the optical films obtained in Production Examples C1 to C6, and are conventional polarizing plates (thickness: 40 μm) bonded to both sides of the polarizer P. : 110 μm), the performance of the polarizer P was maintained, and the heat-and-moisture resistance was good.
On the other hand, Comparative Examples 1 and 2 are polarizing plates using the optical films obtained in Comparative Production Examples C1 and C2, but the moisture and heat resistance was poor.

  The polarizing plate of the present invention can be used for various optical applications. Specifically, the polarizing plate is used for liquid crystal display devices, organic EL display devices, touch panel integrated liquid crystal display devices, touch panel integrated organic EL display devices, and the like. Can be used for

Claims (18)

A polarizing plate in which a film-like or sheet-like cured product of an active energy ray-curable composition is directly formed as a protective film on at least one surface of a polarizer formed from a polyvinyl alcohol-based resin, and the cured product has a temperature of 23 ° C. A polarizing plate having a photoelastic coefficient (hereinafter, simply referred to as “photoelastic coefficient”) of 15 × 10 ⁻¹² Pa ⁻¹ or less.   The polarizing plate according to claim 1, wherein the composition contains urethane (meth) acrylate (A).   The polarizing plate according to claim 2, wherein the component (A) is urethane (meth) acrylate having no aromatic group.   The polarizing plate according to claim 2, wherein the component (A) is a reaction product of a polyol having a number average molecular weight of less than 500, a non-yellowing organic polyisocyanate, and a hydroxyl group-containing (meth) acrylate. 3. The composition contains a polymer (B) having a photoelastic coefficient of 5 × 10 ⁻¹² Pa ⁻¹ or less, and the cured product has a photoelastic coefficient of 10 × 10 ⁻¹² Pa ⁻¹ or less. The polarizing plate according to claim 4.   The polarizing plate according to claim 5, wherein the component (B) is a homopolymer or copolymer of a monomer having a (meth) acryloyl group. The composition is a compound having an ethylenically unsaturated group having a glass transition temperature of a homopolymer having a glass transition temperature of 0 ° C. or higher, containing a compound (C) other than the component (A), and the photoelastic coefficient of the cured product is 10 ×. It is 10 <^-12> Pa < ^{-1 >} or less, The polarizing plate of any one of Claims 2-6.   The polarizing plate according to claim 7, wherein the component (C) is a compound having tertiary and quaternary carbon atoms.   The polarizing plate according to claim 7, wherein the component (C) is a compound having an aliphatic cyclic skeleton or a compound having a saturated cyclic skeleton containing a hetero atom. After applying the active energy ray-curable composition to at least one surface of a polarizer formed from a polyvinyl alcohol-based resin, a method for producing a polarizing plate that irradiates active energy rays from the coated surface or the polarizer side, The manufacturing method of the polarizing plate which uses the thing whose photoelastic coefficient of hardened | cured material is 15 * 10 <^-12> Pa < ^{-1 >} or less as said composition.   The manufacturing method of the polarizing plate of Claim 10 in which the said composition contains urethane (meth) acrylate (A).   The method for producing a polarizing plate according to claim 11, wherein the component (A) is urethane (meth) acrylate having no aromatic group.   The method for producing a polarizing plate according to claim 12, wherein the component (A) is a reaction product of a polyol having a number average molecular weight of less than 500, a non-yellowing organic polyisocyanate, and a hydroxyl group-containing (meth) acrylate. . 12. The composition contains a polymer (B) having a photoelastic coefficient of 5 × 10 ⁻¹² Pa ⁻¹ or less, and the cured product has a photoelastic coefficient of 10 × 10 ⁻¹² Pa ⁻¹ or less. The manufacturing method of the polarizing plate of any one of Claims 13.   The method for producing a polarizing plate according to claim 14, wherein the component (B) is a homopolymer or copolymer of a monomer having a (meth) acryloyl group. The composition is a compound having an ethylenically unsaturated group having a glass transition temperature of a homopolymer having a glass transition temperature of 0 ° C. or higher, containing a compound (C) other than the component (A), and the photoelastic coefficient of the cured product is 10 ×. It is 10 <^-12> Pa < ^-1 > or less, The manufacturing method of the polarizing plate of any one of Claims 11-15.   The method for producing a polarizing plate according to claim 16, wherein the component (C) is a compound having tertiary and quaternary carbon atoms.   The method for producing a polarizing plate according to claim 16, wherein the component (C) is a compound having an aliphatic cyclic skeleton or a compound having a saturated cyclic skeleton containing a hetero atom.

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