WO2013081101A1

WO2013081101A1 - Active energy beam-cured composition for optical film, optical film, polarizer protective film, and polarizing plate

Info

Publication number: WO2013081101A1
Application number: PCT/JP2012/081075
Authority: WO
Inventors: 谷内　健太郎; 貴之竹本; 望月　克信; 加藤　久雄
Original assignee: 東亞合成株式会社
Priority date: 2011-12-01
Filing date: 2012-11-30
Publication date: 2013-06-06
Also published as: KR20140099294A; TW201329628A; CN104024294A; JPWO2013081101A1

Abstract

[Problem] To provide: an active energy beam-curable composition for optical films that combines a low photoelastic coefficient and low retardation, good resistance to moist heat, and outstanding flexibility; an optical film obtained using said composition; a polarizer protective film; and a polarizing plate. [Solution] An energy beam-curable composition for forming optical films, containing: (A) urethane (meth)acrylate (A) having a photoelastic coefficient at 23°C when cured (hereinafter merely referred to as the "photoelastic coefficient") not exceeding 30 x 10^-12Pa^-1, and (B) a polymer other than the component (A) and which has a photoelastic coefficient not exceeding 5 x 10^-12Pa^-1. The photoelastic coefficient when cured does not exceed 10 x 10^-12Pa^-1, in-plane retardation at the front and at a diagonal of 40° and total retardation in the thickness direction when cured as measured at a thickness of 40μm does not exceed 5nm.

Description

Active energy ray-curable composition for optical film formation, optical film, polarizer protective film, and polarizing plate

The present invention relates to an active energy ray-curable composition used for forming an optical film, an optical film obtained by curing the composition, and a polarizing plate using the same as a polarizer protective film. Belongs.
The “optical film” in the present invention means “optical film or sheet”, and the thickness is not particularly limited. Further, acrylate or methacrylate is represented as (meth) acrylate.

In recent years, with the increase in size of liquid crystal displays, it has become necessary to increase the size of optical films such as polarizer protective films and retardation films that optically compensate liquid crystals.
However, when the size of the optical film is increased, the bias of external force is generated. Therefore, when the optical film is made of a material that easily changes birefringence due to the 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 a triacetyl cellulose (hereinafter also referred to as “TAC”) film generally used as a polarizer protective film. The absolute value of the photoelastic coefficient is large, and light leakage and white spots occur due to the generation of stress birefringence accompanying the polarizer contraction.

Moreover, the TAC film has a retardation in the thickness direction, although the retardation with respect to the incident light in the front direction is small. Such retardation significantly affects viewing angle characteristics as the size of liquid crystal displays increases.
Therefore, a material that can achieve both a low photoelastic coefficient and a low retardation is required.

Patent Document 1 discloses that photoelasticity is reduced by blending an acrylic resin having negative photoelasticity with a cellulose ester resin having positive photoelasticity.

In Patent Document 2, a low photoelastic coefficient and a low retardation are achieved by blending polyvinyl pyrrolidone with a cellulose ester resin.

Patent Document 3 discloses that an optical film made of urethane (meth) acrylate has a small photoelastic coefficient.

Republished patent WO2009 / 081607 JP 2008-111056 A JP 2011-145330 A

In the invention described in Patent Document 1, the retardation is large and the low photoelastic coefficient and the low retardation cannot be achieved at the same time. In addition, because it is based on cellulose with a high water absorption rate, the heat and moisture resistance is not sufficient, and when a polarizing plate using the film as a polarizer protective film is used at high temperature or high humidity, the polarizing plate may be deformed, There is a drawback that the performance of the polarizing plate such as the degree of polarization and the hue deteriorates.
In the invention described in Patent Document 2, since it is a combination of a cellulose ester resin and polyvinylpyrrolidone, there is a problem that the heat and humidity resistance is worse than that of the composition described in Patent Document 1.
In the invention described in Patent Document 3, the absolute value of the photoelastic coefficient is as large as TAC (13 × 10 ⁻¹² Pa ⁻¹ ), which is not satisfactory. Further, the retardation is large, and a low photoelastic coefficient and a low retardation cannot be achieved at the same time.
As described above, optical films that have been studied as materials for polarizer protective films that replace conventional triacetyl cellulose do not have both a low photoelastic coefficient and a low retardation, or have sufficient moisture and heat resistance even if they are compatible. However, when a polarizing plate using the film as a polarizer protective film is used at a high temperature or under high humidity, there are disadvantages that the polarizing plate is deformed and polarizing plate performance such as degree of polarization and hue is lowered.

An object of the present invention is to provide an active energy ray-curable composition for forming an optical film that can achieve an optical film having both a low photoelastic coefficient and a low retardation and excellent in heat and moisture resistance.
Another object of the present invention is to provide an optical film that can be suitably used for polarizer protective film applications, has excellent viewing angle characteristics, and has excellent moisture and heat resistance and adhesiveness.

As a result of intensive studies to solve the above problems, the present inventors have found that the following active energy ray-curable composition can solve the above problems, and have completed the present invention.
The active energy ray-curable composition for forming an optical film of the present invention is a urethane (meth) acrylate (A) having the following photoelastic coefficient 1 of 30 × 10 ⁻¹² Pa ⁻¹ or less of the cured product, and the following photoelastic coefficient. 2 has a value of 5 × 10 ⁻¹² Pa ⁻¹ or less and includes a polymer (B) other than the component (A), and the photoelastic coefficient 1 of the cured product of the composition is 10 × 10 ⁻¹² Pa ^{−. It is 1} or less, and all of the front surface of the cured product and the in-plane retardation at an angle of 40 ° and the retardation in the thickness direction when measured at a thickness of 40 μm are 5 nm or less.
The photoelastic coefficient 1 means a photoelastic coefficient at 23 ° C., and the photoelastic coefficient 2 is an optical film obtained by adding the component (B) at an arbitrary ratio to the component (A) used. The value of the photoelastic coefficient at 23 ° C. is measured and extrapolated from a linear graph of the added quantity and the photoelastic coefficient, and means a value when the added quantity is 100%.

ADVANTAGE OF THE INVENTION According to this invention, the active energy ray hardening-type composition for optical film formation which can make compatible the low photoelastic coefficient and low retardation, and can obtain the optical film excellent in heat-and-moisture resistance can be provided.
Moreover, according to this invention, it can use suitably for a polarizer protective film use, and can provide the optical film excellent in the viewing angle characteristic, and excellent in heat-and-moisture resistance and adhesiveness.

It is a schematic diagram which shows one example of manufacture of the optical film which uses the composition of this invention. It is a schematic diagram which shows another example of manufacture of the optical film which uses the composition of this invention.

The active energy ray-curable composition for forming an optical film of the present invention (hereinafter also simply referred to as “composition”) is a urethane (meta) having a photoelastic coefficient 1 of 30 × 10 ⁻¹² Pa ⁻¹ or less of the cured product. ) Acrylate (A) [hereinafter also referred to simply as “component (A)”. And the following photoelastic coefficient 2 has a value of 5 × 10 ⁻¹² Pa ⁻¹ or less, and the polymer (B) other than the component (A) [hereinafter also simply referred to as “component (B)”. In the case where the cured product of the composition has a photoelastic coefficient 1 of 10 × 10 ⁻¹² Pa ⁻¹ or less and is measured at a thickness of 40 μm, the front surface of the cured product and an in-plane retardation and thickness of 40 ° obliquely are measured. All of the retardation in the length direction is 5 nm or less.
The photoelastic coefficient 1 means a photoelastic coefficient at 23 ° C., and the photoelastic coefficient 2 is an optical film obtained by adding the component (B) at an arbitrary ratio to the component (A) used. The value of the photoelastic coefficient at 23 ° C. is measured and extrapolated from a linear graph of the added quantity and the photoelastic coefficient, and means a value when the added quantity is 100%.
Hereinafter, the present invention will be described in detail. 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. Component (A) The component (A) is a urethane (meth) acrylate having a photoelastic coefficient 1 of a cured product of 30 × 10 ⁻¹² Pa ⁻¹ or less.
By using a compound having a photoelastic coefficient 1 of 30 × 10 ⁻¹² Pa ⁻¹ or less as the photoelastic coefficient 1 of the cured product (A), the photoelastic coefficient 1 of the cured product of the composition is 10 × 10 ⁻¹² Pa ⁻¹ or less. It can be. Moreover, it is preferable that the photoelastic coefficient 1 of the hardened | cured material of (A) component is 5 * 10 < ^-12 > Pa < ^-1 > or more.
The photoelastic coefficient 1 of the cured product (A) is preferably 10 × 10 ⁻¹² to 20 × 10 ⁻¹² Pa ⁻¹ , more preferably 10 × 10 ⁻¹² to 15 × 10 ⁻¹² Pa ⁻¹ . is there.

In the present invention, the photoelastic coefficient is a coefficient representing the ease of change of birefringence due to external force, and the photoelastic coefficient 1 is a photoelastic coefficient at 23 ° C. The closer the value of the photoelastic coefficient is to zero, the smaller the change in birefringence due to external force.
Specifically, the photoelastic coefficient 1 (C) is a value defined by the following equation (1), where σ is an extensional stress and Δn is a birefringence when stress is applied.
C [Pa ⁻¹ ] = Δn / σ (1)
Here, Δn is defined by the following equation (2), 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 (2)
In addition, the photoelastic coefficient 1 in this invention means the value measured at the temperature of 23 degreeC.
As a measuring method of the photoelastic coefficient 1, an optical film obtained by curing the composition of the present invention or a film obtained by curing only the component (A) may be measured by a known birefringence meter. Specifically, for example, an optical film obtained by curing the composition of the present invention or a film obtained by curing only the component (A) is cut into 15 mm × 60 mm, and an automatic birefringence meter (KOBRA-WR, Oji Scientific Instruments) is cut out. The in-plane retardation value when the five-point tension σ is changed in the range of 0N to 10N at room temperature is measured using the A method for obtaining the elastic modulus 1 is preferred.

(A) As a component, the reaction material of a polyol, organic polyisocyanate, and a hydroxyl-containing (meth) acrylate etc. are mentioned, A raw material is selected so that the compound obtained may satisfy the above-mentioned photoelastic coefficient 1.
The component (A) is preferably a urethane (meth) acrylate having two or more (meth) acryloyl groups, and more preferably two (meth) acryloyl groups are urethane (meth) acrylates.
As the component (A), urethane (meth) acrylate having no aromatic group is preferable because of low photoelasticity. 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.
The weight average molecular weight (hereinafter referred to as “Mw”) of the component (A) is preferably 1,000 to 15,000, more preferably 1,000 to 10,000.
In addition, in this invention, Mw is the value which converted the molecular weight measured by the gel permeation chromatography (henceforth "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, and the method for producing the component (A), which are the raw material compounds of the component (A), will be described.

1-1. As the polyol polyol, a diol is preferably used, and various diols can be used.
Examples of the diol include aliphatic diols having 2 to 12 carbon atoms, alicyclic diols having 2 to 12 carbon atoms, polycarbonate diols, polyester diols, and polyether diols.

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, poly Tetramethylene glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexaneglycol, 2,2,4- Examples include trimethyl-1,3-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, norbornane Diol, norbornanedimethanol, decalin dimethanol, 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.

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 diols such as polyethylene polypropoxy block polymer diols, and random polymer diols.

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

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 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 of 3 hydroxyl groups.
The above-mentioned caprolactone adduct of triol is commercially available, and examples thereof include Plaxel 303, 305, 308, 312 and L320ML (manufactured by Daicel Chemical Industries, Ltd.).

These polyols may use only 1 type or may use 2 or more types together.
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.
In the case where mechanical properties are required as the component (A), more specifically, when excellent in breaking strength and tensile modulus are required, the number average molecular weight (hereinafter referred to as “P”) is used as the polyol. -Mn ") is preferably used in combination with a polyol having 500 or more and a polyol having P-Mn of less than 500.
In the present invention, the P—Mn (number average molecular weight) of the polyol is a value determined according to the following formula.

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 are mentioned, and these are used in combination. The polyol having P—Mn of 500 or more is preferably a polyol having P—Mn of 500 or more and 10,000 or more. The polyol having P—Mn of less than 500 is preferably a polyol having P—Mn of 62 or more and less than 500.

1-2. Organic polyisocyanate As organic polyisocyanate, organic diisocyanate is preferable, and non-yellowing type organic diisocyanate is more preferable.
Examples of the non-yellowing organic diisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate, lysine methyl ester diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate (hereinafter also referred to as “IPDI”), and the like. Examples thereof include alicyclic diisocyanates such as 4,4′-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.

1-3. Hydroxyl group-containing (meth) acrylates Hydroxyl group-containing (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxy Hexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, pentaerythritol tri, di or mono (meth) acrylate, and hydroxyalkyl (meth) acrylates such as trimethylolpropane di or mono (meth) acrylate, and caprolactone of these compounds Examples include adducts.
Among the compounds described above, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like are excellent in curability of the composition and flexibility of the cured product. A caprolactone adduct of 2-hydroxyethyl acrylate is preferred.

1-4. (A) Manufacturing method of component (A) The component may be manufactured according to the conventional method.
As the component (A), a polyol and an organic polyisocyanate are reacted to produce an isocyanate group-containing compound, which is reacted with a hydroxyl group-containing (meth) acrylate (hereinafter also referred to as “compound A1”), polyol. , Organic polyisocyanate and hydroxyl group-containing (meth) acrylate compound (hereinafter also referred to as “compound A2”), and the like, and the compound A1 is preferred because the molecular weight is easy to control.
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.

1-5. Preferable component (A) In the present invention, the component (A) is a polycarbonate diol or polyester diol (hereinafter also collectively referred to as “diol a”), aliphatic having 2 to 12 carbon atoms, among those described above Alternatively, urethane (meth) acrylate which is a reaction product of alicyclic diol (hereinafter collectively referred to as “diol b”), non-yellowing organic diisocyanate and hydroxyl group-containing (meth) acrylate is preferable.
Compared with other urethane (meth) acrylates, the component (A) has excellent mechanical strength and light resistance by using diol a as a polyol, diol b as a short-chain diol, and non-yellowing type as an organic diisocyanate. The degree of yellowing after the test is small, and the photoelastic coefficient 1 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 the 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: 5 to 50 mol% and diol b: 50 to 95 mol%, more preferably diol a: 5 to 40 mol% and diol b: 60 to 95 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 95 mol% and triol: 5 to 50 mol%, more preferably diol a and / or b: 60 to 95 mol% and triol: 5 to 40 mol%.

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

Further, in the present invention, as the component (A), among the above-mentioned components, a reaction product of a caprolactone adduct of diol b (a diol having P-Mn of less than 500), a non-yellowing organic diisocyanate, and a hydroxyl group-containing (meth) acrylate Particularly preferred is urethane (meth) acrylate. In the component (A), the cured product of the composition is excellent due to brittleness and flexibility.
In this case, the diol b is preferably a polyol having P-Mn of 62 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.
The caprolactone adduct of hydroxyl group-containing (meth) acrylate is preferably a caprolactone adduct of hydroxyalkyl (meth) acrylate. Furthermore, the reaction ratio of caprolactone to the hydroxyl group-containing (meth) acrylate is preferably greater than 0.1 mol and less than 2.0 mol.
The method for producing 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. Component (B) The component (B) is a polymer having a photoelastic coefficient 2 of 5 × 10 ⁻¹² Pa ⁻¹ or less, and is a polymer other than the component (A). Further, the photoelastic coefficient 2 of the component (B) is preferably −15 × 10 ⁻¹² Pa ⁻¹ or more.
In the present invention, the photoelastic coefficient 2 is the value of the photoelastic coefficient at 23 ° C. of the optical film obtained by adding the component (B) at an arbitrary ratio to the component (A) used as described above. And the value when the addition amount is 100% extrapolated from the linear graph of the addition amount and the photoelastic coefficient is meant.
When graphing the relationship between the addition amount of the component (A) and the component (B) and the photoelastic coefficient, it is preferable to obtain three or more measured values, and the graph can be prepared by the least square method. preferable.
Since the cured product of the component (A) and the cured product of the composition can be formed into a film, the photoelastic coefficient can be directly measured using an automatic birefringence system. Can not be measured directly, the photoelastic coefficient 2 is the photoelastic coefficient.

As described above, the cured product of component (A) has a positive photoelastic coefficient of 1 of 30 × 10 ⁻¹² Pa ⁻¹ or less, preferably 10 × 10 ⁻¹² to 30 × 10 ⁻¹² Pa ^−1. Therefore, by blending the component (B) having a photoelastic coefficient 2 of 5 × 10 ⁻¹² Pa ⁻¹ or less, the photoelastic coefficient 2 of the cured product of the composition is 10 × 10 ^−. It can be ¹² Pa ⁻¹ or less.

The photoelastic coefficient 2 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 .

The Mw of the component (B) may be appropriately set depending on the purpose, and is preferably 1,000 to 100,000, more preferably 1,000 to 50,000.
By making Mw 1,000 or more, the amount of the polymerization initiator and the chain transfer agent can be reduced at the time of producing the component (B), thereby preventing an increase in the photoelastic coefficient 1 and coloring problems of the cured product. On the other hand, by making it 100,000 or less, it is excellent in compatibility with the component (A), and the turbidity of the cured product can be prevented.

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

Specific examples of the monomer having a (meth) acryloyl group include (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 (meta ) (Meth) acrylates such as acrylate, dicyclopentenyl (meth) acrylate, glycidyl (meth) acrylate;
Hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate;
N- (meth) acryloylmorpholine; and (meth) acrylamide, N-methylol acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide and N, N-dimethylaminopropyl (meth) acrylamide And acrylamides.

As a copolymer of a monomer having a (meth) acryloyl group, a copolymer having an amide structure or a carboxyl group has a large negative photoelastic coefficient 2 and is excellent in compatibility with the component (A). preferable.
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 (meth) acrylate and N- (meth) acryloylmorpholine is preferable.
In the case of a copolymer having an amide structure, the proportion of the monomer having an amide structure is preferably 5 to 50 parts by weight with respect to 100 parts by weight as a total of all monomers used.
As a specific example of the copolymer having a carboxyl group, a copolymer of (meth) acrylate and acrylic acid or methacrylic acid is preferable.
In the case of a copolymer having a carboxyl group, the acid value is preferably from 5 to 65 mgKOH / g.

As the homopolymer or copolymer of the monomer having a (meth) acryloyl group, a commercially available product can also be used. For example, Delpet 60N, 80N (Asahi Kasei Chemicals Co., Ltd.), Dialal BR52, BR80, BR83, BR85, BR87, BR88 (Mitsubishi Rayon Co., Ltd.), KT75 (Electrochemical Industry 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 N-vinyl-2-pyrrolidone copolymer monomers 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.

As the N-vinyl-2-pyrrolidone copolymer, a commercially available product can also be used. For example, PVP / VA S-630 (manufactured by IPS Japan Co., Ltd.) and the like can be mentioned.

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.

The polymerization temperature is preferably 30 to 100 ° C. for suspension or emulsion polymerization and 80 to 300 ° C. for bulk or solution polymerization. Furthermore, the polymerization can be carried out using alkyl mercaptan or the like as a chain transfer agent.

As the component (B) in the present invention, a polymer having an ethylenically unsaturated group [hereinafter also referred to as “(UB) component”. Is preferred.
The (UB) component is chemically cross-linked with the (A) component by irradiation with active energy rays. Therefore, when a polymer having a negative photoelastic coefficient 2 having no ethylenically unsaturated group is blended, there is a problem that the flexibility and brittleness of the obtained cured product are reduced. It becomes possible to mix more polymers having a negative value of the coefficient 2, and the photoelastic coefficient 2 of the cured product can be greatly reduced.
Hereinafter, the (UB) component will be described.

2-1. Examples of the ethylenically unsaturated group in the (UB) component (UB) component include a vinyl group, a vinyl ether group, a (meth) acryloyl group, and a (meth) acrylamide group. Among these, the (meth) acryloyl group is particularly preferable, and the acryloyl group is more preferable because the component (B) is easy to produce and has excellent curability by active energy rays.

As the (UB) component, various compounds can be used as long as the photoelastic coefficient 2 is 5 × 10 ⁻¹² Pa ⁻¹ or less and the polymer has an ethylenically unsaturated group, and examples thereof include the following polymers. be able to.
1) Polymer UB1: To a polymer containing a carboxyl group (hereinafter also referred to as “carboxyl group-containing prepolymer”) and / or a polymer containing a hydroxyl group (hereinafter also referred to as “hydroxyl group-containing prepolymer”). Polymer 2 obtained by adding a compound having an isocyanate group and an ethylenically unsaturated group (hereinafter also referred to as “isocyanate-based unsaturated compound”) 2) Polymer UB2: epoxy group and ethylenic group to carboxyl group-containing prepolymer Polymer 3 obtained by adding a compound having an unsaturated group (hereinafter also referred to as “epoxy unsaturated compound”) Polymer UB3: Polymer containing epoxy group (hereinafter referred to as “epoxy group-containing prepolymer”) And a compound having a carboxyl group and an ethylenically unsaturated group (hereinafter referred to as “carboxyl unsaturated group”). Also referred to as objects ".) The following polymer obtained by adding, described polymer UB1 ~ UB3.

2-1-1. Production method of prepolymer As the monomer constituting the prepolymer, a monomer whose photoelastic coefficient 2 of the obtained prepolymer is 5 × 10 ⁻¹² Pa ⁻¹ or less may be appropriately selected. Among them, (meth) acryloyl A compound having a group can be preferably used.
Hereinafter, the manufacturing method of a carboxyl group-containing prepolymer, a hydroxyl group-containing prepolymer, and an epoxy group-containing prepolymer will be described.

2-1-1-1. Production method of carboxyl group-containing prepolymer The carboxyl group-containing prepolymer used in the production of the polymer UB1 and polymer UB2 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). Can be mentioned.

First, a copolymer of a carboxyl unsaturated compound and other unsaturated compounds will be described.

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 2 of the (UB) component obtained is particularly low.

The other unsaturated compound is not particularly limited as long as the photoelastic coefficient 2 of the obtained (UB) component is 5 × 10 ⁻¹² Pa ⁻¹ or less, but is excellent in copolymerizability with the above carboxyl-based unsaturated compound. Therefore, a compound having a (meth) acryloyl group is preferred.
Examples of the compound having a (meth) acryloyl group include 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-methylol acrylamide, 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 2 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, also referred to as “hydroxy acid unsaturated compound”).
Hydroxy 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.

The method for producing a copolymer of a carboxyl unsaturated compound and other unsaturated compounds is not particularly limited, and known methods such as suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization and the like are used without any limitation. The method can be used.
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.

In the case of producing by a solution polymerization method, the raw material monomer to be used is dissolved in an organic solvent, a thermal polymerization initiator is added, and the mixture is heated and stirred. In the case of synthesizing by radical polymerization by a solution polymerization method, the raw material monomer to be used is dissolved in an organic solvent, a thermal radical polymerization initiator is added, and the mixture is heated and stirred. Further, a chain transfer agent can be used to adjust the molecular weight of the polymer, if necessary.

Organic solvents used in the solution polymerization method include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; ethers such as propylene glycol monomethyl ether; aromatic carbonization such as toluene and xylene. Hydrogen; and aliphatic hydrocarbons such as hexane, heptane and mineral spirit.

Examples of thermal polymerization initiators include azo initiators such as azobisisobutyronitrile, azobisisovaleronitrile, azobiscyclohexanecarbonitrile, and azobiscyanovaleric acid;
Organic peroxides such as t-butyl peroxypivalate, t-hexyl peroxypivalate, dilauroyl peroxide, di (2-ethylhexyl) peroxydicarbonate, di-t-butyl peroxide and dicumyl peroxide And hydrogen peroxide-iron (II) salt, peroxodisulfate-sodium hydrogen sulfite, cumene hydroperoxide-iron (II) salt, and the like.
What is necessary is just to set suitably the usage-amount of a thermal-polymerization initiator according to the target molecular weight. The use ratio of the thermal polymerization initiator is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight in total of all monomers used.

The chain transfer agent may be used as necessary to adjust to the above-mentioned Mw range, but the use of the chain transfer agent may increase the photoelastic coefficient 2 of the component (B). It is preferable to adjust the chain transfer agent in as small an amount as possible.
A known chain transfer agent can be used as the chain transfer agent. For example, in addition to mercaptans such as dodecyl mercaptan, lauryl mercaptan, glycidyl mercaptan, 2-mercaptoethanol, 3-mercaptopropionic acid, mercaptoacetic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, α- And methyl styrene dimer.
These chain transfer agents may be used alone or in combination of two or more.
The amount of the chain transfer agent used may be the same as the amount normally used, and is preferably 0.01 to 7 parts by weight as a total of 100 parts by weight of all monomers used.

The polymer obtained as described above is a polymer having a carboxyl group in the side chain.
What is necessary is just to set suitably according to the ratio of the ethylenically unsaturated group finally introduce | transduced as a copolymerization ratio of a carboxyl type unsaturated compound and other unsaturated compounds, and a carboxyl type unsaturated compound and other unsaturated compounds total The amount of carboxyl unsaturated compound is preferably 1 to 40% by weight and the other unsaturated compound 60 to 99% by weight with respect to 100% by weight.
The Mw of the copolymer of the carboxyl unsaturated compound and the other unsaturated compound may be appropriately set according to the purpose, and is preferably 1,000 to 100,000, preferably 1,000 to 50,000. It is more preferable that

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.
Examples of 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 with respect to a 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.

The polymer obtained as described above is a polymer having a carboxyl group at the terminal.
The Mw of the terminal carboxyl group-containing polymer may be appropriately set according to the purpose, and is preferably 1,000 to 100,000, more preferably 10,000 to 50,000.

The carboxyl group-containing prepolymer is preferably a terminal carboxyl group-containing polymer because the number and position of ethylenically unsaturated groups introduced into one molecule can be controlled.

2-1-1-2. Method for Producing Hydroxyl-Containing Prepolymer Hydroxyl-containing prepolymer used in polymer UB1 includes 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. And a polymer containing a hydroxyl group at the terminal obtained by polymerizing (hereinafter also referred to as “terminal hydroxyl group-containing polymer”).

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

As a method for producing a copolymer of a hydroxyl-based unsaturated compound and another unsaturated compound, it can be produced according to the same method as described above.

The copolymer obtained as described above is a copolymer having a hydroxyl group in the side chain.
What is necessary is just to set suitably according to the ratio of the ethylenically unsaturated group finally introduce | transduced as a copolymerization ratio of a hydroxyl-type unsaturated compound and other unsaturated compounds, and a hydroxyl-type unsaturated compound and other unsaturated compounds The amount of the hydroxy unsaturated compound is 1 to 40% by weight and the other unsaturated compound is 60 to 99% by weight with respect to 100% by weight of the total compound.
The Mw of the copolymer of the hydroxy unsaturated compound and the other unsaturated compound may be appropriately set according to the purpose, and is preferably 1,000 to 100,000, preferably 1,000 to 50, More preferably, it is 000.

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.
Examples of 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.
The ratio of the chain transfer agent having a hydroxyl group may be appropriately set according to the ratio of the ethylenically unsaturated group to be finally introduced. Part by weight is preferred.
As the polymerization method, the same method as described above can be employed.

The polymer obtained as described above is a polymer having a hydroxyl group at the terminal.
The Mw of the terminal hydroxyl group-containing polymer may be appropriately set depending on the purpose, and is preferably 1,000 to 100,000, more preferably 1,000 to 50,000.

As the hydroxyl group-containing prepolymer, a terminal hydroxyl group-containing polymer is preferable because the number and position of ethylenically unsaturated groups introduced into one molecule can be controlled.

2-1-1-3. Production Method of Epoxy Group-Containing Prepolymer Examples of the epoxy group-containing prepolymer used in the polymer UB3 include a copolymer of an epoxy unsaturated compound and other unsaturated compounds.

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

As a method for producing a copolymer of an epoxy unsaturated compound and other unsaturated compounds, it can be produced according to the same method as described above.

The copolymer obtained as described above is a copolymer having an epoxy group in the side chain.
What is necessary is just to set suitably according to the ratio of the ethylenically unsaturated group finally introduce | transduced as a co-weight ratio of an epoxy type unsaturated compound and other unsaturated compounds, and an epoxy type unsaturated compound and other unsaturated compounds total The amount of the epoxy unsaturated compound is 1 to 40% by weight and the other unsaturated compound is 60 to 99% by weight with respect to the amount of 100% by weight.
The Mw of the copolymer of the epoxy unsaturated compound and the other unsaturated compound may be appropriately set according to the purpose, and is preferably 1,000 to 100,000, preferably 1,000 to 50,000. It is more preferable that

2-1-2. (UB) the production method (UB) of component are carboxyl group-containing prepolymer, hydroxyl group-containing prepolymer, with respect to the epoxy group-containing prepolymer, a compound having a functional group and an ethylenically unsaturated group capable of reacting with these prepolymers Is introduced by addition reaction.
What is necessary is just to follow a conventional method as a method of addition reaction.
For example, in any case, it can be produced by adding each compound to a prepolymer in an organic solvent, in an aqueous medium or without a solvent. As conditions for each addition reaction, a reaction temperature, a reaction time, and a catalyst may be selected according to each reaction.
Hereinafter, the addition reaction will be described.

Polymer UB1 is produced by adding an isocyanate-based unsaturated compound to a carboxyl group-containing prepolymer and / or a hydroxyl group-containing prepolymer by a urethanization reaction.

Examples of the isocyanate-based unsaturated compound include the organic polyisocyanates mentioned in the preparation of the component (A), preferably 2-isocyanatoethyl (meth) acrylate, monoadducts of IPDI and 2-hydroxyethyl acrylate, and the like. Can be mentioned.

Examples of the catalyst for the urethanization reaction include organometallic compounds.
Examples of organometallic compounds include di-n-butyltin oxide, di-n-butyltin dilaurate, di-n-butyltin, di-n-butyltin diacetate, di-n-octyltin oxide, di-n-octyltin dilaurate, Organic tin compounds such as monobutyltin trichloride, di-n-butyltin dialkyl mercaptan, di-n-octyltin dialkyl mercaptan; organic lead compounds such as lead oleate, lead 2-ethylhexanoate, lead naphthenate, lead octenoate An organic bismuth compound such as bismuth octylate;

The proportion of the catalyst used in the urethanization reaction is preferably 0.001 to 0.5 parts by weight, and preferably 0.001 to 0.5 parts per 100 parts by weight of the total amount of the carboxyl group-containing prepolymer and the isocyanate unsaturated compound. 1 part by weight is more preferred.

The reaction ratio of the isocyanate-based unsaturated compound to the carboxyl group-containing prepolymer is preferably 0.8 to 1.0 mol of the isocyanate-based unsaturated compound with respect to a total of 1 mol of carboxyl groups in the carboxyl group-containing prepolymer.
The reaction ratio of the isocyanate unsaturated compound to the hydroxyl group-containing prepolymer is preferably 0.8 to 1.0 mol of the isocyanate unsaturated compound with respect to 1 mol of hydroxyl groups in the hydroxyl group-containing prepolymer.
By making the reaction ratio of the isocyanate-based unsaturated compound less than 1 mol with respect to 1 mol of the carboxyl group and / or hydroxyl group in the prepolymer, the (UB) component is converted into a polymer having a carboxyl group and / or a hydroxyl group can do.

Polymer B2 is produced by adding an epoxy unsaturated compound to a carboxyl group-containing prepolymer.
In addition, the polymer B3 is produced by adding a carboxyl unsaturated compound to an epoxy group-containing prepolymer.

Examples of the epoxy unsaturated compound include the same compounds as described above, and examples of the carboxyl unsaturated compound include the same compounds as described above.

Catalysts for the addition reaction of carboxyl group and epoxy group include tertiary amines such as triethylamine, tripropylamine, tributylamine, dimethyllaurylamine, triethylenediamine and tetramethylethylenediamine; triethylbenzylammonium chloride, trimethylcetylammonium bromide, tetra Quaternary ammonium salts such as butylammonium bromide, quaternary phosphonium salts such as triphenylbutylphosphonium bromide and tetrabutylphosphonium bromide; and phosphine compounds such as triphenylphosphine and tributylphosphine. Among these, it is preferable to use triphenylphosphine because the resin is less colored.

As a ratio of the catalyst in the reaction, the total amount of the carboxyl group-containing prepolymer and the epoxy unsaturated compound is 100 parts by weight, or the total amount of the epoxy group-containing prepolymer and the carboxyl unsaturated compound is 100 parts by weight. 0.1 to 5.0 parts by weight is preferable, and 0.1 to 3.0 parts by weight is more preferable.

The reaction ratio of the epoxy unsaturated compound to the carboxyl group-containing prepolymer is preferably 0.8 to 1.2 mol of the epoxy unsaturated compound with respect to 1 mol of the total carboxyl groups in the carboxyl group-containing prepolymer.
The reaction ratio of the carboxyl unsaturated compound to the epoxy group-containing prepolymer is preferably 0.8 to 1.2 mol of the carboxyl unsaturated compound with respect to a total of 1 mol of epoxy groups in the epoxy group-containing prepolymer.

The above addition reaction can be carried out in any case following the production of the prepolymer, preferably following the solution polymerization.
In that case, a polymerization inhibitor is used to suppress polymerization during the addition reaction. Examples of the polymerization inhibitor include dibutylhydroxytoluene, hydroquinone, hydroquinone monomethyl ether and the like, and it is preferable to add 50 to 1,000 ppm with respect to the reaction solution.

2-3. What is necessary is just to set suitably according to the objective as an average number of the ethylenically unsaturated groups in a (UB) component (UB) component.
The average number of ethylenically unsaturated groups in the (UB) component is preferably 0.5 to 5.0 on average per molecule, more preferably 1.0 to 3.0 on average. It is. When the number of ethylenically unsaturated groups in one molecule is 0.5 or more on average, it is sufficiently incorporated into the matrix of the component (A), and heat resistance, moist heat resistance and brittleness are sufficient. When the average is 5.0 or less, the crosslinking density is appropriate, the film is excellent in toughness, and the photoelastic coefficient 1 of the cured product of the composition can be lowered.
The average number (f) of ethylenically unsaturated groups in the (UB) component can be represented by the following formula (3).

X: Number average molecular weight Mn of prepolymer measured by GPC
Y: Molecular weight of the compound unit having a reactive group in the prepolymer Z: Number of parts by weight of the compound unit having a reactive group in the prepolymer The compound unit having a reactive group in the prepolymer is a carboxyl group-containing compound unit A monomer unit derived from a carboxyl unsaturated compound if it is a prepolymer, a monomer unit derived from a hydroxyl unsaturated compound if it is a hydroxyl group-containing prepolymer, or a monomer unit derived from an epoxy unsaturated compound if it is an epoxy group-containing prepolymer Means each.

As the (UB) component, since an ethylenically unsaturated group can be efficiently introduced into the molecular terminal, the terminal carboxyl group-containing polymer or terminal hydroxyl group-containing polymer is used as a prepolymer from the viewpoint that both brittleness and photoelastic coefficient 2 can be achieved at high dimensions A polymer produced from a polymer (hereinafter also referred to as a macromonomer) is preferred.
Specific examples of the macromonomer include polymers B1 and B2 produced from a terminal carboxyl group-containing polymer, and polymer B1 produced from a terminal hydroxyl group-containing polymer, and these f values are 1.0.

3. The active energy ray-curable composition for forming an optical film The present invention is an active energy ray-curable composition for forming an optical film comprising the component (A) and the component (B) as essential components.
As a manufacturing method of a composition, what is necessary is just to follow a conventional method, using (A) component and (B) component, using other components further as needed, and obtaining these by stirring and mixing. it can.

In the composition of the present invention, the photoelastic coefficient 1 of the cured product needs to be 10 × 10 ⁻¹² Pa ⁻¹ or less. Thereby, a hardened | cured material becomes what becomes difficult to produce the birefringence change by external force, and when used as a polarizer protective film, light leakage and white spot can be prevented. The photoelastic coefficient 1 of the cured product of the composition of the present invention is preferably −10 × 10 ⁻¹² Pa ⁻¹ or more.

In the composition of the present invention, all of the front surface of the cured product, the oblique in-plane retardation of 40 ° and the retardation in the thickness direction when measured at a thickness of 40 μm must be 5 nm or less. Thereby, when it uses as a polarizer protective film, the liquid crystal display excellent in the viewing angle characteristic can be obtained. A cured product having a retardation larger than 5 nm has a problem of poor viewing angle characteristics.
Further, it is preferable that the in-plane retardation of the cured product when measured at a thickness of 40 μm is 1 nm or less, the in-plane retardation at an oblique angle of 40 ° is 5 nm or less, and the retardation in the thickness direction is 5 nm or less. The retardation values are preferably -5 nm or more.

In the present invention, the retardation means a phase difference caused by birefringence when the transmitted light is considered to be decomposed into two linearly polarized lights orthogonal to each other when the linearly polarized light enters the optical film.
Specifically, the in-plane retardation (Re) and the thickness direction retardation (Rth) are nx, ny (where nx ≧ ny), and nz is the refractive index in the thickness direction. When the film thickness is d, it is a value defined by the following formula.
Re = (nx−ny) × d
Rth = {(nx + ny) / 2−nz} × d
Furthermore, in the present invention, the in-plane retardation at an angle of 40 ° means an in-plane retardation when linearly polarized light is incident on the optical film at an angle of 40 °.

The proportion of the component (A) and the component (B) 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 (B). Component (B) is preferably 10 to 70% by weight, more preferably 40 to 80% by weight of component (A) and 20 to 60% by weight of component (B).
By making the ratio of the component (A) 30% by weight or more, the cured product obtained can be excellent in mechanical properties, and on the other hand, by making it 90% by weight or less, a low photoelastic coefficient and a low retardation are obtained. It can be compatible.

The composition of the present invention essentially comprises the component (A) and the component (B), but various components can be blended depending on the purpose.
Specifically, an ethylenically unsaturated compound other than the component (A) [hereinafter also referred to as the component (C). ], Photopolymerization initiator [hereinafter also referred to as component (D). ] Organic solvent [hereinafter also referred to as component (E). ], A polymerization inhibitor or / and an antioxidant, a light resistance improver, and the like.
Hereinafter, these components will be described.

Component (C) The component (C) is an ethylenically unsaturated compound other than the component (A).
(C) 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 (C) include (meth) acrylates other than the component (A) [hereinafter also referred to as “other (meth) acrylates”. And N-vinyl-2-pyrrolidone.

As other (meth) acrylates, compounds having one (meth) acryloyl group [hereinafter also referred to as “monofunctional (meth) acrylates”. ] Or a compound having two or more (meth) acryloyl groups [hereinafter also referred to as “polyfunctional (meth) acrylate”. ] Etc. are mentioned.

Specific examples of monofunctional (meth) acrylates include 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, 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 = 1-4) (meth) acrylate, p-cumylphenol EO modified (n = 1-4) (meth) acrylate, phenyl (meth) acrylate, о-phenylphenyl (meth) acrylate, p-cumylphenyl ( And (meth) acrylate, N- (meth) acryloylmorpholine, N-vinylformamide, N- (meth) acryloyloxyethylhexahydrophthalimide, N- (meth) acryloyloxyethyltetrahydrophthalimide, 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, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) Acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (n = 5-14) di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) Acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol (n = 5 to 14) di (meth) acrylate, 1,3-butylene glycol Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, polybutylene glycol (n = 3 to 16) di (meth) acrylate, poly (1-methylbutylene glycol) (n = 5 to 20) di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, Examples thereof include bifunctional (meth) acrylates of tricyclodecane dimethylol di (meth) acrylate.
In the above, EO modification means ethylene oxide modification, and n means the number of repeating alkylene oxide units.

(C) As a component, only 1 type of the above-mentioned compound may be used, or 2 or more types may be used together.

As the component (C), among the compounds described above, a compound having a homopolymer photoelastic coefficient 1 smaller than the component (A) is preferable, and a compound having a homopolymer photoelastic coefficient 1 negative is more preferable.
Specific examples of the compound are particularly preferably isobornyl (meth) acrylate, t-butyl (meth) acrylate, N- (meth) acryloylmorpholine and N-vinyl-2-pyrrolidone.

The proportion of the component (C) may be appropriately set according to the purpose, and may be an amount that does not reduce the flexibility of the resulting cured product, but the total amount of the component (A) and the component (B) is 100 weights. The amount is preferably 1 to 100% by weight, more preferably 1 to 80% by weight, based on the part.

(D) Component (D) A component is a photoinitiator.
(D) 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 the component (D), but a small amount of the component (D) can be added as necessary for improving curability.

Component (D) 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- (methyl Vinyl) phenyl] propanone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one, 2-methyl-1- [4 -(Methylthio)] phenyl] -2-morpholinopropan-1-one, 2-benzene Dil-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) Aromatic ketone compounds such as butan-1-one, Adekaoptomer N-1414 (manufactured by ADEKA Corporation), 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 Benzophenones such as (diethylamino) benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, N, N′-tetraethyl-4,4′-diaminobenzophenone and 4-methoxy-4′-dimethylaminobenzophenone Compound;
Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate and bis (2,6- Acylphosphine oxide compounds such as 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 can be used alone or in combination of two or more.

As a blending ratio of the component (D), when the component (C) is included with respect to a total of 100 parts by weight of the component (A) and the component (B), the component (A), the component (B), and ( C) 0.01 to 10% by weight is preferable with respect to 100 parts by weight of the total amount of components, and more preferably 0.1 to 5% by weight.
By setting the blending ratio of component (D) 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.

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

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

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

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, but sulfur secondary antioxidants, phosphorus secondary antioxidants are preferable. Subsequent antioxidants can also be added.
When the total blending ratio of these polymerization inhibitors or / and antioxidants includes the component (C) with respect to a total of 100 parts by weight of the component (A) and the component (B), the component (A), The content is preferably 0.001 to 3% by weight, more preferably 0.01 to 0.5% by weight, based on 100 parts by weight of the total amount of the component (B) and the component (C).

The composition of the light resistance improver present invention, the light resistance improving agent such as an ultraviolet absorber or light stabilizer may be added.
Examples of ultraviolet absorbers 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-isooctyloxyphenyl) -s-triazine;
2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4,4'-tri Hydroxybenzophenone, 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 (1,2,2,6). , 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) and the component (C) when the component (C) is included with respect to 100 parts by weight of the component (A) and the component (B). ) It is preferably 0 to 5% by weight, more preferably 0 to 1% by weight, based on 100 parts by weight of the total amount of the components.

4). Method of Use The composition of the present invention can employ various methods of use depending on the purpose of forming the optical film.
Specifically, a method of applying a composition to a substrate and irradiating it with an active energy ray to cure, applying a composition to a substrate and bonding it to another substrate, and further irradiating with an active energy ray And a curing method, a method of pouring the composition into a mold having a recess, and curing by irradiation with active energy rays.

As the substrate, any of a peelable substrate and a substrate having no releasability (hereinafter, also referred to as “non-releasable substrate”) can be used.
Examples of the peelable substrate include a release-treated film, a peelable surface untreated film, a metal (hereinafter also referred to as “release material”), and the like.
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 achieve low haze or impart surface smoothness to the optical film obtained from the composition of the present invention, the surface roughness (centerline average roughness) Ra is 150 nm or less as a peelable substrate. It is preferable to use a material, and a substrate having an Ra of 1 to 100 nm is more preferable. Furthermore, the haze is preferably 3.0% or less. Moreover, it is preferable that a haze is 0.01% or more.
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.

Examples of the non-releasable substrate include various plastics other than those described above, such as cellulose acetate resins such as polyvinyl alcohol, triacetyl cellulose and diacetyl cellulose, acrylic resin, polyester, polycarbonate, polyarylate, polyethersulfone, norbornene and the like. And cyclic polyolefin resins having a cyclic olefin as a monomer.

In coating the composition of the present invention, as a composition, in order to prevent the generation of defects such as mixing of foreign substances and voids, and to have excellent optical properties, the obtained optical film has a raw material component. It is preferable to use a purified product after stirring and mixing.
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 smaller the filtration accuracy, the better. However, if the filtration 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 active energy rays include electron beams, ultraviolet rays and visible rays. Among these, an electron beam is more preferable in that it is not always necessary to add a photopolymerization initiator and the cured product is excellent in heat resistance and light resistance.

The irradiation conditions such as dose and irradiation intensity in the active energy ray irradiation may be appropriately set according to the composition to be used, the substrate, the purpose and the like.

5). Optical Film The composition of the present invention can be preferably used for the production of an optical film.
Hereinafter, the optical film will be described.
Hereinafter, a part of the description will be given with reference to FIGS. 1 and 2.

5-1. Manufacturing method of optical film As a manufacturing method of an optical film, a conventional method may be followed. For example, the composition may be applied to a substrate and then irradiated with active energy rays.

FIG. 1 is a schematic view showing an example of a preferred method for producing an optical film composed of a release material / cured product.
In FIG. 1, (1) means a release material.
When the composition is a solventless type (FIG. 1: F1), the composition is applied to a release material [FIG. 1: (1)]. When the composition contains an organic solvent or the like (FIG. 1: F2), the composition is applied to a release material [FIG. 1: (1)] and then dried to evaporate the organic solvent or the like (FIG. 1: 1). -1).
By irradiating an active energy ray with respect to the sheet | seat in which a composition layer (2) is formed in a mold release material, the optical film comprised from a mold release material / hardened | cured material is obtained. The active energy ray is usually irradiated from the composition layer side, but can also be irradiated from the release material side.
In the above, if a release material is used as the substrate (1), an optical film composed of a release material / cured product can be produced.

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 that the coating is performed so that the film thickness after drying the organic solvent or the like is 5 to 200 μm. The thickness is preferably 10 to 100 μm.

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.
As the composition after heating and drying, the proportion of the organic solvent is preferably 1% by weight or less.

FIG. 2 is a schematic view showing an example of a preferable method for producing an optical film composed of a release material / cured product / release material.
In FIG. 2, (1), (3), and (4) mean release materials.
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). The composition layer (2) is laminated with the release material (3) and then irradiated with active energy rays, or after being irradiated with the active energy rays, the release material (4) is laminated to obtain a release material, a cured product and a release material. An optical film formed in this order is obtained.

Although the example which used the mold release material as a base material was described in the said FIG.1 and 2, an optical film can also be manufactured using a non-molding property base material.
For example, in FIG. 1, a non-releasable base material is used in place of the release material of (1) and is cured by irradiation with active energy rays in the same manner as described above, and is composed of a non-releasable base material / cured product. An optical film can also be manufactured.
Moreover, in FIG. 2, as a mold release material of any of (1), (3), and (4), a non-mold release substrate is used, and it is cured by irradiation with active energy rays in the same manner as described above. An optical film composed of a release material / cured product / non-releasing substrate and an optical film composed of a non-releasing substrate / cured material / non-releasing substrate can also be produced.
Specific examples of the embodiment include a method in which a polarizer is used as a non-releasing substrate, a composition is applied and irradiated with active energy rays, and a protective film is directly formed on the polarizer. .
In the case of producing a lens sheet, a transparent plastic film is used as a non-releasing substrate, a composition is applied, and then a metal mold is bonded to the coating film as a release material. Examples include a method of irradiating active energy rays from the side.

In the above example, the optical film is produced by applying the composition to a substrate. However, when producing an optical film having a large film thickness, the composition is formed on a mold having a specific recess. An optical film can also be produced by pouring an object and irradiating active energy rays in the same manner as described above to cure the composition.

5-2. Use of optical film The optical film formed from the composition of the present invention can be used for various optical uses, more specifically, a polarizer protective film for polarizing plates used in liquid crystal display devices, etc. Examples include a support film for a prism sheet and a light guide film. Other uses include lens sheets such as Fresnel lenses and lenticular lenses, and the lenticular lenses can be used for naked-eye 3D displays.

Hereinafter, a polarizing plate using a polarizer protective film (hereinafter, also simply referred to as “protective film”) formed from the composition of the present invention will be described.

The polarizing plate is a structure in which a protective film is laminated on at least one surface of a polarizer.
The polarizing plate may be manufactured by directly coating and curing the composition of the present invention on a polarizer to form a protective film, or may be manufactured by bonding a polarizer and a protective film.

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 absorption type polarizer having excellent visibility. The thickness of the absorptive polarizer is preferably 5 to 40 μm.
The polarizing plate of the present invention is a polarizing plate in which the optical film of the present invention is laminated as a protective film on at least one surface of a polarizer, and is bonded by an adhesive.

As the adhesive used for bonding the polarizer and the protective film, any adhesive can be used in consideration of each adhesive property.
Specific examples of the adhesive include polyvinyl alcohol-based aqueous adhesives, solvent-based adhesives, hot-melt adhesives, and solvent-free adhesives. Solvent-free active energy ray-curable adhesives It can be used suitably.
Examples of the active energy ray curable adhesive include a photo cation curable adhesive, a photo radical curable adhesive, and a hybrid adhesive using 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, 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 it has a protective film on both surfaces of a polarizer, what has the protective film of this invention on both surfaces is the 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 also 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 A1 [Production of Component (A)]
A 500 mL reaction vessel equipped with a stirrer, a thermometer and a condenser was charged with IPDI: 145.9 g as an isocyanate and dibutyltin dilaurate: 0.07 g as a catalyst at room temperature (25 ° C., the same applies hereinafter), and 5% by volume. These were heated under stirring in a nitrogen atmosphere containing oxygen until the liquid temperature reached 70 ° C.
Polycarbonate diol [Duranol T-5651 manufactured by Asahi Kasei Chemicals Corporation, number average molecular weight 1,000]: 43.0 g, 1,4-butanediol: 33.5 g and methyl ethyl ketone (hereinafter also referred to as “MEK”) as an alcohol solution. ): 65.0 g of the mixed solution was added dropwise so that the internal temperature became 75 ° C. or lower, and then reacted at an internal temperature of 80 ° C. for 2 hours.
Thereafter, 2-hydroxyethyl acrylate (hereinafter also referred to as “HEA”): 57.6 g, 2,6-di-t-butyl-4-methylphenol (hereinafter also 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 was 75 ° C. or lower, and reacted for 3 hours to obtain an infrared absorption spectrum apparatus (FT-manufactured by Perkin Elmer). The spectrum was measured by IR Spectrum 100), and it was confirmed that the isocyanate groups were completely consumed. Thus, a MEK solution (solid content 80%) containing urethane acrylate (hereinafter referred to as “UA-1”) was obtained.
The weight average molecular weight (hereinafter also referred to as Mw) of UA-1 was 2,300 as a result of measurement by GPC (solvent: tetrahydrofuran, column: HSPgel HR MB-L manufactured by Waters).
As a result of measuring the photoelastic coefficient 1 according to the following description, it was 12.3 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A2 [Production of Component (A)]
In Production Example A1, IPDI as the isocyanate: 127.8 g, Duranol T5651 as the alcohol solution: 37.6 g, tricyclo [5.2.1.0 ^2,6 ] decanedimethanol (OCDEA TCDDM): 64.1 g and A MEK solution (solid content 80%) containing urethane acrylate (hereinafter referred to as “UA-2”) was obtained in the same manner except that MEK: 65.0 g mixed solution and HEA: 50.5 g were used. .
As a result of measuring Mw and photoelastic coefficient 1 of the obtained UA-2 in the same manner as in Production Example A1, the Mw was 2,300 and the photoelastic coefficient 1 was 9.7 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A3 [Production of Component (A)]
In Production Example A1, IPDI: 151.4 g as isocyanate, polycaprolactone triol (manufactured by Daicel Chemical Industries, Ltd.) Plaxel 303, number average molecular weight 300): 18.3 g, Duranol T5651: 20.4 g, 1, A MEK solution containing urethane acrylate (hereinafter referred to as “UA-3”) was carried out in the same manner except that a mixed solution of 4-butanediol: 28.2 g and MEK: 65.0 g and HEA: 61.6 g were used. (Solid content 80%) was obtained.
Mw and photoelastic coefficient 1 of the obtained UA-3 were measured in the same manner as in Production Example A1, and as a result, Mw was 2,400 and photoelastic coefficient 1 was 13.5 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A4 [Production of Component (A)]
In Production Example A1, IPDI as isocyanate: 148.8 g, polyester diol as alcohol solution [Exp4358 manufactured by DIC Corporation, esterified product of adipic acid and ethylene glycol, number average molecular weight 500]: 42.1 g, 1,4-butane A MEK solution (solid content) containing urethane acrylate (hereinafter referred to as “UA-4”) was carried out in the same manner except that a mixed solution of diol: 30.4 g and MEK: 65.0 g and HEA: 58.7 g were used. 80%).
As a result of measuring Mw and photoelastic coefficient 1 of the obtained UA-4 in the same manner as in Production Example A1, Mw was 1,900 and photoelastic coefficient 1 was 12.6 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A5 [Production of Component (A)]
In Production Example A1, a mixed solution of IPDI: 99.6 g and MEK: 50.0 g as isocyanate, spiroglycol (hydroxyl value: 369 mg KOH / g, P-Mn: 304) as alcohol (SPG manufactured by Mitsubishi Gas Chemical Co., Inc.) : 74.4 g and MEK (used for washing adhering to the reaction vessel after addition of SPG powder): 25.5 g, ε-caprolactone 1 mol adduct of 2-hydroxyethyl acrylate as hydroxyl-containing acrylate [Corporation] Daicel FA1DDM]: MEK solution (80% solid content) containing urethane acrylate (hereinafter referred to as “UA-5”), except that a mixed solution of 95.6 g and MEK: 5.0 g was used. Got.
As a result of measuring Mw and photoelastic coefficient 1 of the obtained UA-5 in the same manner as in Production Example A1, Mw was 2,400 and photoelastic coefficient 1 was 11.6 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A6 [Production of Component (A)]
In Production Example A1, except that IPDI: 134 g as isocyanate, 1,4-butanediol: 34.2 g and MEK: 65.0 g as a solution of alcohol, and FA1DDM: 104.8 g as hydroxyl group-containing acrylate were used. The same operation was performed to obtain a MEK solution (solid content 80%) containing urethane acrylate (hereinafter referred to as “UA-6”).
The Mw and photoelastic coefficient 1 of the obtained UA-6 were measured in the same manner as in Production Example A1, and as a result, the Mw was 2,200 and the photoelastic coefficient 1 was 17.5 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example A′1 [ Production of urethane acrylate other than component (A)]
A 500 mL reaction vessel equipped with a stirrer, a thermometer, and a condenser was charged with IPDI: 196.0 g as an isocyanate and dibutyltin dilaurate: 0.035 g as a catalyst at room temperature under an atmosphere of nitrogen containing 5% oxygen by volume. Was stirred until the liquid temperature reached 70 ° C.
After dropping 49.5 g of Duranol T5651 as alcohol so that the internal temperature became 75 ° C. or lower, the reaction was carried out at an internal temperature of 80 ° C. for 2 hours.
Thereafter, HEA: 104.5 g and BHT: 0.09 g were added dropwise so that the internal temperature was 75 ° C. or lower, and reacted for 3 hours to obtain urethane acrylate (hereinafter referred to as “UA′1”).
As a result of measuring Mw and photoelastic coefficient 1 of UA′1 obtained in the same manner as in Production Example A1, Mw was 4,400 and photoelastic coefficient 1 was 153 × 10 ⁻¹² Pa ⁻¹ .

○ Production Example B1 [Production of Component (B)]
In a 500 mL reaction vessel equipped with a stirrer, a thermometer, and a condenser, methyl methacrylate (hereinafter also referred to as “MMA”): 20.0 g, N-acryloylmorpholine (hereinafter also referred to as “ACMO”): 20 0.0 g, methyl isobutyl ketone (hereinafter also referred to as “MIBK”): 200 g was charged and uniformly dissolved at room temperature.
While stirring the contents of the flask, the internal temperature was raised to 92 ° C. in a nitrogen atmosphere. After the internal temperature became constant, MMA: 80.0 g was consumed for 4 hours, and ACMO: 80.0 g was applied for 3 hours. On the other hand, a polymerization initiator solution consisting of 10 g of V-65 [2,2′-azobis-2,4-dimethylvaleronitrile, manufactured by Wako Pure Chemical Industries, Ltd.] and 40 parts of MIBK was added over 5 hours. Feeded continuously.
After completion of continuous supply, aging was performed for 3 hours while maintaining the internal temperature at 92 ° C. As a result, a solution (solid content 47%) containing a polymer having a negative photoelastic coefficient 2 (hereinafter referred to as “LP-1”) Obtained.
The Mw of the obtained LP-1 was measured in the same manner as in Production Example A1, and as a result, the Mw was 10,000. Further, the photoelastic coefficient 2 of LP-1 was measured according to the following, and found to be −5.0 × 10 ⁻¹² Pa ⁻¹ .
In addition, about the photoelastic coefficient 2 of (B) component, the photoelastic coefficient value in 23 degreeC of the optical film obtained by adding (B) component in arbitrary ratios with respect to the used urethane acrylate was measured, The photoelastic coefficient value when the addition amount was 100% extrapolated from the linear graph of the addition amount and the photoelastic coefficient was calculated and described.

(1) Examples 1 to 12 and Comparative Examples 1 to 7 (Production of Composition)
Components shown in Table 1 below were charged in a stainless steel container in the proportions 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: polymethyl methacrylate resin, Mitsubishi Rayon Co., Ltd. Dianal BR-87 [solid content: 100%, Mw; 25,000, acid value: 10.5 mg KOH / g, photoelastic coefficient 2; -6 × 10 ^-12 Pa ^-1 ]
LP-3: N-vinyl-2-pyrrolidone / vinyl acetate copolymer, PVP / VA S-630 (solid content: 100%, Mw: 45,000, photoelastic coefficient 2) manufactured by IS Japan Co., Ltd. -9 × 10 ^-12 Pa ^-1 ]
Dc1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one, DAROCUR-1173 manufactured by BASF Japan Ltd.

(2) Examples F1 to F10 and Comparative Examples F1 to F6 (Production of optical film by electron beam curing)
A film “Lumirror 50-T60” (surface untreated polyethylene terephthalate film, thickness 50 μm, hereinafter referred to as “Lumirror”) manufactured by Toray Industries, Inc., having a width of 300 mm and a length of 300 mm, was used in Examples 1 to 10 and Comparative Examples 1 to The composition obtained in 6 was coated with an applicator so that the film thickness after drying at 80 ° C. for 10 minutes was 40 μm.
Then, after laminating 300 mm width x 300 mm length on the composition layer, an acceleration voltage of 200 kV, a dose of 50 kGy (adjusted by the beam current and the conveyance speed), oxygen by an electron beam irradiation apparatus manufactured by NHV Corporation, oxygen Electron beam irradiation was performed under conditions of a concentration of 300 ppm or less to obtain an optical film.
After curing, the film was peeled off from Lumirror and used for evaluation of photoelastic coefficient 1, in-plane and thickness direction retardation described later.

(3) Examples F11 to F12 and Comparative Example 7 (Production of optical film by ultraviolet curing)
The UV curable composition obtained in Examples 11 to 12 and Comparative Example 7 was applied to a Lumirror having a width of 300 mm and a length of 300 mm with an applicator so that the film thickness after drying at 80 ° C. for 10 minutes was 40 μm. did.
Then, after laminating 300 mm width x 300 mm length on the composition layer, a conveyor type ultraviolet irradiation device (high pressure mercury lamp, lamp height 12 cm, 365 nm irradiation intensity 400 mW / cm ² ) manufactured by Eye Graphics Co., Ltd. (Measurement value of UV POWER PUCK manufactured by Fusion UV Systems Japan Co., Ltd.) was adjusted to carry out ultraviolet irradiation with an integrated light quantity of 1,000 mJ / cm ² to obtain an ultraviolet curable optical film.
After curing, it was peeled off from Lumirror and used for the evaluation described later.

[Photoelastic coefficient 1]
The optical films obtained in Examples and Comparative Examples were cut into 15 mm × 60 mm, and using an automatic birefringence meter (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.), a 5-point tension in the range of 0N to 10N at room temperature. The in-plane retardation value when σ was changed was measured, and the photoelastic coefficient 1 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
(In the formula, Δn represents stress birefringence, σ represents tension, and C represents photoelastic coefficient 1.)
Moreover, about the photoelastic coefficient 1 of the hardened | cured material of (A) component, only the (A) component was hardened by the method similar to manufacture of the optical film by the said electron beam hardening, a film was produced, and it measured similarly to the above. .

[In-plane and thickness direction retardation]
For the optical films obtained in Examples and Comparative Examples, front and oblique in-plane retardation (hereinafter, “0 ° Re” respectively) using a phase difference measuring device (KOBRA-21ADH manufactured by Oji Scientific Instruments). And “40 ° Re”) and thickness direction retardation (hereinafter also referred to as “Rth”). The results are shown in Table 2.

Examples F1 to F12 are optical films obtained from the compositions of Examples 1 to 12 which are the compositions of the present invention, and the photoelastic coefficient 1 is the light of a TAC conventionally used as a polarizer protective film. The elastic modulus was smaller than 13 × 10 ⁻¹² Pa ^{−1 of 1} , and there was no concern about light leakage or white spots. Further, the thickness direction retardation was smaller than the Rth of TAC (40 μm) of 30 to 40 nm, and the viewing angle characteristics were excellent.
On the other hand, Comparative Examples F1 to F5 did not contain the component (B), and therefore, the photoelastic coefficient 1 or the thickness direction retardation was large, and both could not be reduced simultaneously. In Comparative Examples F6 to F7, although the component (B) was included, the photoelastic coefficient 1 of UA-5 alone was large, so the photoelastic coefficient 1 could not be sufficiently reduced.

○ Production Example B2 [ Production of carboxyl group-containing prepolymer]
In a 1 L reaction vessel equipped with a stirrer, a thermometer and a condenser, methyl methacrylate (hereinafter also referred to as “MMA”): 52.0 g, 2-hydroxyethyl methacrylate (hereinafter also referred to as “HEMA”): 16.0 g, methacrylic acid (hereinafter also referred to as “MAA”): 12.0 g, 3-mercaptopropionic acid (hereinafter also referred to as “MPA”): 3.2 g, methyl isobutyl ketone (hereinafter referred to as “MIBK”) 480g was charged and dissolved uniformly at room temperature.
While stirring the contents of the flask, the internal temperature was raised to 92 ° C. under a nitrogen atmosphere, and after the internal temperature became constant, MMA: 468.0 g, HEMA: 144.0, MAA: 108.0, MPA: 748.8 g of a mixture of 28.8 g was added over 5 hours, while 2,2′-azobis-2,4-dimethylvaleronitrile [V-65 manufactured by Wako Pure Chemical Industries, Ltd.]. Hereinafter, it is also referred to as “V-65”. ]: A polymerization initiator solution composed of 6.4 g and MEK: 80 g was continuously added over 5.5 hours.
After completion of the continuous addition, aging was carried out for 2 hours while maintaining the internal temperature at 92 ° C. to obtain a solution (solid content: 62%) of a carboxyl group-containing prepolymer (hereinafter referred to as “LP-4”).
Mn, Mw, and photoelastic coefficient 2 of the obtained LP-4 were measured in the same manner as in Production Example B1, and as a result, Mn was 3,200, Mw was 5,800, and photoelastic coefficient 2 was 0.2 × 10 ^−12. -Pa ^-1 .
The results are shown in Table 3. In addition, the numbers in Table 3 are described as ratios when converted to a ratio of 100% by weight of the whole monomers used, and the used organic solvents and their ratios are omitted.

○ Production Example B3 [ Production of carboxyl group-containing prepolymer]
In Production Example B2, the same operation was carried out except that the raw materials used were changed as shown in Table 3, and a carboxyl group-containing prepolymer having a negative photoelastic coefficient 2 (hereinafter referred to as “LP-5”). Solution (solid content 62%) was obtained.
Mn, Mw, and photoelastic coefficient 2 of LP-5 obtained were measured in the same manner as in Production Example B1. As a result, Mn was 4,400, Mw was 11,000, and photoelastic coefficient 2 was −2.0 × 10 ^{−. 12} · Pa ⁻¹ . The results are shown in Table 3.

○ Production Example B4 [ Production of terminal carboxyl group-containing polymer]
MMA: 400.0 g, MPA: 5.8 g, and MIBK: 640.0 g were charged into a 1 L reaction vessel equipped with a stirrer, a thermometer, and a condenser, and uniformly dissolved at room temperature.
While stirring the contents of the flask, the internal temperature was raised to 92 ° C. under a nitrogen atmosphere, and after the internal temperature became constant, MMA: 400.0 g and MPA: 8.64 g were added over 3 hours. On the other hand, a polymerization initiator solution (1) consisting of V-65: 1.3 g and MEK: 32 g was added for 4 hours, and a polymerization initiator solution (2) consisting of V-65: 5.2 g and MEK: 128.0 g. Each was added continuously over 2 hours.
After completion of the continuous addition, aging was performed for 2 hours while maintaining the internal temperature at 92 ° C., and a solution of a terminal carboxyl group-containing polymer (hereinafter referred to as “LP-6”) having a negative photoelastic coefficient of 2 (solid content 51). %).
Mn, Mw, and photoelastic coefficient 2 of the obtained LP-6 were measured in the same manner as in Production Example B1, and as a result, Mn was 6,000, Mw was 12,000, and photoelastic coefficient 2 was −4.0 × 10 ^{−. 12} · Pa ⁻¹ . The results are shown in Table 3.

○ Production Example B5 [Production of Component (B)]
LP-4: 350.0 g (solid content 62%) was charged into a 1 L reaction vessel equipped with a stirrer, a thermometer, and a cooler, heated to 92 ° C. Stir for 1 hour. Thereafter, BHT: 0.11 g as a polymerization inhibitor, DBTDL: 0.05 g as a catalyst, 2-acryloyloxyethyl isocyanate [Karenz AOI manufactured by Showa Denko KK]. Hereinafter, it is also referred to as “AOI”. ]: 43.0 g was charged all at once and stirred for 4 hours.
Completion of this urethanization reaction confirmed the disappearance of the isocyanate group in the solution by infrared spectroscopy. In this way, a solution (solid content 64%) of component (B) (hereinafter referred to as “ULP-1”) was obtained.
Mn, Mw, and photoelastic coefficient 2 of the obtained ULP-1 were measured in the same manner as in Production Example B1. Also, the f value of ULP-1 was calculated according to equation (3).
Table 4 shows the results of Mn, Mw, f value of ULP-1, unsaturated group introduction site, and photoelastic coefficient 2.
In addition, the numbers in Table 4 are described as ratios in terms of 100% by weight of the total monomers used in the prepolymer production, and the used solvents and their ratios are omitted.

○ Production Examples B6 to 16 [Production of component (B)]
In Production Example B5, the same procedure was followed except that the types and ratios of the monomers used in the prepolymer production were changed as described in Tables 4 and 5 and the types and ratios of the compounds used in the addition reaction were changed. And a solution of component (B) (solid content 51 to 64%) was obtained.
The Mn, Mw, f value and photoelastic coefficient 2 of the obtained ULP-2 to 12 were measured by the same method as in Production Example B6. The results are shown in Table 4 and Table 5 together with the unsaturated group introduction site.
In Production Examples B11 and B14, the completion of the reaction between the carboxyl group and the epoxy group was confirmed by using an autotitrator [COM-900, manufactured by Hiranuma Sangyo Co., Ltd.] to confirm the disappearance of the acid value in the reaction solution. did.

F in Table 4 and Table 5 is the average number of ethylenically unsaturated groups in one molecule.
The abbreviations in Tables 3 to 5 including those defined above are shown below.
• MMA: methyl methacrylate • HEMA: 2-hydroxyethyl methacrylate • MAA: methacrylic acid • MA: methyl acrylate • GMA: glycidyl methacrylate • ACMO: acryloylmorpholine • V-65: 2,2′-azobis-2,4-dimethyl Valeronitrile, MPA: 3-mercaptopropionic acid, MTG: 2-mercaptoethanol, DM: dodecyl mercaptan, AOI: 2-acryloyloxyethyl isocyanate, AA: acrylic acid, MOI: 2-methacryloyloxyethyl isocyanate, DBTDL : Dibutyltin dilaurate • TBAB: Tetrabutylammonium bromide • BHT: 2,6-di-t-butyl-4-methylphenol

(4) Examples U1 to U20 and Comparative Examples U1 to U2 (Production of compositions)
The components shown in Tables 6 to 9 below were charged in a stainless steel container in the proportions shown in Tables 6 to 9, and stirred with a magnetic stirrer while heating to obtain a composition.

In Table 7, M309 means trimethylolpropane triacrylate [Aronix M-309 manufactured by Toagosei Co., Ltd.].

(5) Examples UF1 to UF20 and Comparative Examples UF1 and UF2 (production of optical film by electron beam curing)
Examples U1-U20 and Comparative Examples U1- The composition obtained in U2 was coated with an applicator so that the film thickness after drying at 120 ° C. for 10 minutes was 40 μm.
Then, after laminating 300 mm width x 300 mm length on the composition layer, an acceleration voltage of 200 kV and a dose of 150 kGy (adjusted by the beam current and the conveyance speed), oxygen by an electron beam irradiation apparatus manufactured by NHV Corporation, oxygen Electron beam irradiation was performed under conditions of a concentration of 300 ppm or less to obtain an optical film.
After curing, the film was peeled off from the Lumirror, and the photoelastic coefficient 1, in-plane and thickness direction retardation were evaluated by the same method as described above. Further, cutting property and bending resistance were evaluated according to the following methods.

[Cutting]
In order to evaluate the flexibility of the produced film, the cutting property when cut with a cutter knife was evaluated according to the following criteria. The results are shown in Table 10.
○: A state in which cutting can be performed smoothly △: Slightly lacking in smoothness ×: A state in which a cross-section is cracked during cutting

[Bending resistance]
In order to evaluate the flexibility of the produced film, the resistance when the film cut into 15 mm × 150 mm was bent 180 ° was evaluated according to the following criteria. The results are shown in Table 10.
○: No cracking after 3 times Δ: Cracking once or twice ×: Cracking once

Examples UF1 to UF17 are optical films obtained from the compositions of Examples U1 to U17, which are the compositions of the present invention, and the photoelastic coefficient 1 is the light of TAC conventionally used as a polarizer protective film. The elastic modulus was smaller than 13 × 10 ⁻¹² Pa ^{−1 of 1} , and there was no concern about light leakage or white spots. Further, the thickness direction retardation was smaller than the Rth of TAC (40 μm) of 30 to 40 nm, and the viewing angle characteristics were excellent. Furthermore, it was excellent in flexibility.
On the other hand, Examples UF18 to UF20 are compositions having a component (B) ′ having no ethylenically unsaturated group although it is a polymer having a low photoelastic coefficient 1 or a negative value (Comparative Example). An optical film manufactured from U18 to U20), which was excellent in photoelastic coefficient 1 and retardation as in the Examples, but was poor in flexibility.
Comparative Example UF1 is an optical film produced from a composition (Comparative Example U1) that does not contain the component (B), and has a large photoelastic coefficient 1 and thickness direction retardation, and both cannot be simultaneously reduced. . Comparative example UF2 is an optical film manufactured from a composition (comparative example U2) using a urethane acrylate different from component (A), and has a large photoelastic coefficient 1.

○ Production example PL1 [ 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 the polarizer P).
For the obtained polarizer P, the degree of polarization and the single transmittance were measured using a spectrophotometer with a polarizing prism (UV-2200, manufactured by Shimadzu Corporation), and found to be 99.99% and 43.1%, respectively. there were.

○ Production Example V1 [ Production of UV-curable adhesive]
50 parts of bisphenol A diglycidyl ether (Japan Epoxy Resin Co., Ltd. jER807), 20 parts of tetrahydrofurfuryl acrylate (Osaka Organic Chemical Co., Ltd. THF-A), 4-hydroxylbutyl acrylate (Nippon Kasei Co., Ltd.) 30 parts of 4-HBA), iodonium (4-methylphenyl) [4- (2-methylpropyl) phenyl] hexafluorophosphate (BASF Japan) as a photopolymerization initiator (hereinafter also referred to as “photoinitiator”) 4 parts of IRGACURE250 manufactured by Co., Ltd. and 1 part of 2,4-diethylthioxanthone (Kayacure DETX-s manufactured by Nippon Kayaku Co., Ltd.) are placed in a stainless steel container and stirred with a magnetic stirrer until uniform. A curable adhesive (hereinafter referred to as adhesive UVX1) was obtained.

(6) Examples P1, P2 and Comparative Example P1 (Production of Polarizing Plate)
Using the optical films obtained in Examples F3 and F5 and Comparative Example F6 as the polarizer protective film, adhesive UVX1 was applied to both sides of the polarizer P with a film thickness of 5 μm, and the optical films were bonded together. Conveyor speed by conveyor type ultraviolet irradiation device (high pressure mercury lamp, lamp height 15 cm, 365 nm irradiation intensity 370 mW / cm ² (measured value of UV POWER PUCK manufactured by Fusion UV Systems Japan Co., Ltd.)) Was adjusted, and ultraviolet rays with an integrated light quantity of 220 mJ / cm ² were applied to obtain a polarizing plate (width 100 mm × length 100 mm).
In addition, no corona treatment was performed on any of the polarizer protective films.

(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 11.

[Adhesiveness between polarizer protective film and polarizer]
In the polarizing plates obtained in the examples and comparative examples, the adhesive properties of the polarizer protective film and the polarizer P were evaluated by the following criteria when twisted by hand twisting. The results are shown in Table 11.
A: The polarizer and the polarizer protective film are integrated with each other so that peeling does not occur.
X: Peeling is recognized between the polarizer and the polarizer protective film.

[Moisture and heat resistance of polarizing plate]
The polarizing plates obtained in the examples and comparative examples were visually evaluated based on the following criteria for the presence or absence of deformation of the samples after leaving them in a constant temperature and humidity chamber at 60 ° C. and 90% RH for 120 hours. The results are shown in Table 11.
○: Deformation is not seen.
X: Deformation was observed.

Examples P1 and P2 are polarizing plates using the optical films obtained in Examples F3 and F5, which are the compositions of the present invention. The performance of the polarizer P is maintained, and the adhesiveness and heat and humidity resistance are high. It was good.
On the other hand, Comparative Example P1 is a polarizing plate using the optical film obtained in Comparative Example F6, but the performance of the polarizer P is maintained and the adhesiveness is good, but the heat and humidity resistance is reduced. did.

(7) Example P3 to Example P12 (Production of polarizing plate)
A polarizing plate was prepared in the same manner as in Example P1 except that the optical films obtained in Examples F1, F2, F4, and F6 to F12 were used as the polarizer protective film, and the wet heat resistance was evaluated.
All the polarizing plates of Examples P3 to P12 had good wet heat resistance.

○ Production Example V2 [ Production of UV-curable adhesive]
40 parts of bisphenol A diglycidyl ether (Japan Epoxy Resins Co., Ltd. jER807), 20 parts of tetrahydrofurfuryl acrylate (THF-A, Osaka Organic Chemical Co., Ltd.), 4-hydroxylbutyl acrylate (manufactured by Nippon Kasei Co., Ltd.) 4-HBA), 30 parts of isocyanuric acid ethylene oxide modified di- and triacrylate (Aronix M-313 manufactured by Toagosei Co., Ltd.), 50 weight of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate as a photoinitiator 6 parts of a 1% propylene carbonate solution (CPI-100P manufactured by San Apro) and 1 part of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 manufactured by BASF Japan Ltd.) are put into a stainless steel container and uniformly mixed with a magnetic stirrer And stirred until the ultraviolet curing adhesive (hereinafter, referred to as adhesive UVX2.) Was obtained.

(8) Example UP1, UP2 and Comparative Example UP1 (Production of Polarizing Plate)
A polarizing plate (width 100 mm × length 100 mm) was used in the same manner as in Example P1, except that the optical films obtained in Examples UF7, UF10 and Comparative Example UF2 were used as the polarizer protective film, and UVX2 was used as the adhesive. )
In addition, no corona treatment was performed on any of the polarizer protective films.
About the polarizing plate obtained by the Example and the comparative example, a polarization degree and single-piece | unit transmittance | permeability are measured by the method similar to the said Example P1, and the adhesiveness of a polarizer protective film and a polarizer is the same as the above. In addition, the heat and humidity resistance of the polarizing plate was evaluated. The results are shown in Table 12.

Examples UP1 and UP2 are polarizing plates using the optical film obtained in Examples UF7 and UF10, which are the compositions of the present invention. The performance of the polarizer P is maintained, and the adhesiveness and heat and humidity resistance are high. It was good and effective as a protective film for a polarizer.
On the other hand, Comparative Example UP1 is a polarizing plate using the optical film obtained in Comparative Example UF2, but the performance of the polarizer P is maintained and the adhesiveness is good, but the heat and humidity resistance is reduced. did.

(9) Example UP3 to Example UP20 (Production of Polarizing Plate)
A polarizing plate was prepared in the same manner as in Example UP1 except that the optical films obtained in Examples UF1 to UF6, UF8, UF9, and UF11 to F20 were used as the polarizer protective film, and the moisture and heat resistance was evaluated.
All the polarizing plates of Examples UP3 to UP20 had good heat and humidity resistance.

The active energy ray-curable composition for forming an optical film of the present invention can be suitably used for the production of an optical film.
Furthermore, as described in detail above, the optical film of the present invention is suitably used in a polarizer protective film application.

Claims

Urethane (meth) acrylate (A) having the following photoelastic coefficient 1 of the cured product of 30 × 10 −12 Pa −1 or less, and
The following photoelastic coefficient 2 has a value of 5 × 10 −12 Pa −1 or less, and includes a polymer (B) other than the component (A),
The following photoelastic coefficient 1 of the cured product of the composition is 10 × 10 −12 Pa −1 or less,
An active energy ray-curable composition for forming an optical film, wherein the front surface of the cured product and the in-plane retardation at an angle of 40 ° and the retardation in the thickness direction when measured at a thickness of 40 μm are all 5 nm or less.
The photoelastic coefficient 1 means a photoelastic coefficient at 23 ° C., and the photoelastic coefficient 2 is an optical film obtained by adding the component (B) at an arbitrary ratio to the component (A) used. The value of the photoelastic coefficient at 23 ° C. is measured and extrapolated from a linear graph of the added quantity and the photoelastic coefficient, and means a value when the added quantity is 100%.
The active energy ray-curable composition for forming an optical film according to claim 1, wherein the component (A) is a compound having no aromatic group.
The active energy for forming an optical film according to claim 1 or 2, wherein the component (A) is an oligomer having two or more (meth) acryloyl groups and having a weight average molecular weight of 1,000 to 15,000. Line curable composition.
The active energy ray-curable composition for forming an optical film according to any one of claims 1 to 3, wherein the component (A) is a reaction product of a polyol, an organic polyisocyanate, and a hydroxyl group-containing (meth) acrylate. .
In the component (A),
The polyol is an aliphatic or alicyclic diol having 2 to 12 carbon atoms, or a polycarbonate diol or polyester diol and an aliphatic or alicyclic diol having 2 to 12 carbon atoms,
The active energy ray-curable composition for forming an optical film according to claim 4, wherein the organic polyisocyanate is a non-yellowing organic diisocyanate.
In the component (A),
The polyol is an aliphatic or alicyclic diol having 2 to 12 carbon atoms having a number average molecular weight of 62 or more and less than 500,
The organic polyisocyanate is a non-yellowing organic diisocyanate;
The active energy ray-curable composition for forming an optical film according to claim 4, wherein the hydroxyl group-containing (meth) acrylate is a caprolactone adduct of the hydroxyl group-containing (meth) acrylate.
The active energy ray-curable composition for forming an optical film according to any one of claims 1 to 6, wherein the component (B) is a homopolymer or a copolymer of a monomer having a (meth) acryloyl group. object.
The active energy ray curable type for optical film formation according to claim 7, wherein the component (B) is a copolymer of a monomer having a (meth) acryloyl group, which is a copolymer having an amide structure or a carboxyl group. Composition.
The active energy ray-curable composition for forming an optical film according to any one of claims 1 to 6, wherein the component (B) is an N-vinyl-2-pyrrolidone copolymer.
The active energy ray-curable composition for forming an optical film according to any one of claims 1 to 9, wherein the component (B) is a polymer having an ethylenically unsaturated group.
The active energy ray-curable composition for forming an optical film according to claim 10, wherein the ethylenically unsaturated group in the component (B) is a (meth) acryloyl group.
The component (B) is
A polymer obtained by adding a compound having an epoxy group and an ethylenically unsaturated group to a polymer containing a carboxyl group,
A polymer obtained by adding a compound having an isocyanate group and an ethylenically unsaturated group to a polymer containing a carboxyl group and / or a polymer containing a hydroxyl group, and
The polymer according to claim 11 or 12, which is at least one selected from the group consisting of polymers obtained by adding a compound having a carboxyl group and an ethylenically unsaturated group to a polymer containing an epoxy group. An active energy ray-curable composition for forming an optical film.
The active energy for forming an optical film according to claim 12, wherein the polymer containing a carboxyl group, the polymer containing a hydroxyl group, or the polymer containing an epoxy group is a copolymer of a compound having a (meth) acryloyl group. Line curable composition.
The optical film according to claim 12 or 13, wherein the polymer containing a carboxyl group or the polymer containing a hydroxyl group is a polymer containing a carboxyl group at a terminal or a polymer containing a hydroxyl group at a terminal, respectively. An active energy ray-curable composition for formation.
15. The composition according to claim 1, comprising 10 to 80% by weight of component (A) and 20 to 90% by weight of component (B) based on the total amount of component (A) and component (B). The active energy ray-curable composition for forming an optical film as described.
The active energy ray-curable composition for optical film formation according to any one of claims 1 to 15, which is an electron beam curable composition for optical film formation.
An optical film obtained by forming a cured product of the composition according to any one of claims 1 to 15 into a film shape or a sheet shape.
A polarizer protective film comprising the optical film according to claim 17.
A method for producing an optical film, comprising: applying a composition according to any one of claims 1 to 15 to a sheet-like substrate; and irradiating active energy rays from the coated surface side or the sheet-like substrate side.
The method for producing an optical film according to claim 19, wherein the sheet-like substrate is a peelable substrate.
A sheet-like substrate is coated with the composition according to any one of claims 1 to 15, and another sheet-like substrate is bonded to the coated surface of the composition, and then the sheet-like substrate. The manufacturing method of the optical film which irradiates an active energy ray from either side of these.
The method for producing an optical film according to claim 21, wherein either one or both of the sheet-like base materials are peelable base materials.
A polarizing plate in which the polarizer protective film according to claim 18 is laminated on at least one surface of a polarizer formed of a polyvinyl alcohol resin, and the polarizer is attached to the polarizer protective film via an adhesive layer. A bonded polarizing plate.