JP2007070465A - Photopolymerizable composition and light controlling film produced by curing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-controlling film scattering an incident light having a specific incident angle range and a photopolymerizable composition advantageous for producing the film. <P>SOLUTION: This composition comprises: (A) a compound having in the molecule thereof a polymerizable carbon-carbon bond; (B) a compound having in the molecule thereof a polymerizable carbon-carbon bond, wherein a refractive index of a homopolymer produced by polymerizing this compound differs from that of a homopolymer produced by polymerizing the compound (A); and (C) a compound having in the molecule thereof a structure represented by formula (I), wherein R<SB>1</SB>represents a branched hydrocarbon group; R<SB>2</SB>represents a hydrogen atom, a hydrocarbon group or the like; and X represents a hydrocarbon group or a sulfur atom. This light-controlling film is produced by curing the composition through irradiating a UV light to it. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light control film that scatters incident light in a specific angle range and transmits incident light in a specific angle range other than that, and a composition that provides the film.

A light control film in which incident light in a specific angle region is scattered to give a high haze value (opaque), and incident light in a specific angle region other than that is transmitted to give a low haze value (transparency). In order to protect privacy, it is used as a viewing angle control film by being attached to a window glass or a cash dispenser touch panel, or as an optical film such as a viewing angle widening film of a flat panel display.
Such a light control film is obtained by photocuring a composition comprising a photopolymerizable compound in which two or more photopolymerizable compounds are combined such that the refractive indexes of homopolymers of the respective compounds are different. A membrane is used. Recently, for the purpose of expanding the angle range that gives a high haze value, an ultraviolet absorber represented by the formula (VIII), urethane diacrylate (refractive index: 1.49), 2,4,6-tribromophenyl acrylate, 2- About the composition of the photopolymerizable compound which mixed hydroxy-3-phenoxypropyl acrylate (refractive index 1.526) and 2-hydroxy-2-methylpropiophenone (polymerization initiator), depending on the light incident angle, low haze Although there is almost no angle range, the light control film gives a high haze value of 90% or more in a wide angle range, and has a high haze value in an incident angle range of 17 to 19 °, and 5% at an incident angle of 120 °. It is disclosed that a light control film having the following low haze angle range can be obtained (Patent Document 1).

Japanese Patent Laid-Open No. 2003-165807 (Example, FIGS. 13 and 15)

Optical films such as viewing angle widening films scatter incident light in a wide angle range to give high haze (opacity), and transmit incident light in other angle ranges to sufficiently low haze (transparency) ) Is required.
An object of the present invention is to provide a light control film having a wide angle range of high haze value, a high maximum haze value, and a sufficiently low haze angle range, and a photopolymerizable composition suitable for the film. It is to be.

（式中、Ｒ_１は炭素数が４〜１２の分枝状炭化水素基を表し、Ｒ_２は、水素原子、ハロゲン原子、置換されていてもよい炭素数１〜８の炭化水素基、置換されていてもよいアルコキシ基、置換されていてもよいアミノ基を表す。Ｘは炭素数１〜１２の炭化水素基、炭素数１〜４のアルキリデン基、又は硫黄原子を表す。） The inventors of the present invention have studied a compound that replaces the ultraviolet absorber. As a result, the present inventors have found that a photopolymerizable composition containing a specific compound provides a light control film that solves this problem, and has completed the present invention.
The present invention is a composition containing the following compounds (A) to (C), and a light control film obtained by irradiating and curing the composition with ultraviolet rays.
(A): Compound having a polymerizable carbon-carbon bond in the molecule (B): Compound having a polymerizable carbon-carbon bond in the molecule, and the refractive index of the homopolymer of the compound is the compound (A) Compound (C) different from the refractive index of the homopolymer of: a compound having a structure represented by the following (I) in the molecule and not containing a polymerizable carbon-carbon bond:

(Wherein R ₁ represents a branched hydrocarbon group having 4 to 12 carbon atoms, and R ₂ represents a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group having 1 to 8 carbon atoms, or a substituted group. And represents an optionally substituted alkoxy group and an optionally substituted amino group, and X represents a hydrocarbon group having 1 to 12 carbon atoms, an alkylidene group having 1 to 4 carbon atoms, or a sulfur atom.)

The light control film provided by the photopolymerizable composition of the present invention scatters incident light in a wide angle range to give a high haze value (opaque), and is sufficient to hardly scatter incident light in other angle regions. Give low haze (transparency).
Moreover, since the photopolymerizable composition of this invention does not contain a ultraviolet absorber, it hardens | cures rapidly and is excellent in productivity.

Hereinafter, the present invention will be described in detail.
The compounds (A) and (B) of the present invention are compounds having a polymerizable carbon-carbon bond. Here, the polymerizable carbon-carbon bond means a carbon-carbon double bond capable of addition polymerization or a carbon-carbon triple bond capable of addition polymerization. Specifically, for example, vinyl group, allyl group, styryl group, acryloyl group, methacryloyl group, acrylamide group, trans-1-oxo-2-butenoxy group, cinnamoyl group, butadiene structure, polymerizable conjugated bond, cyclopentene ring structure And the like, and the like. As the polymerizable carbon-carbon bond, an acryloyl group and a methacryloyl group are preferable, and an acryloyl group is particularly preferable.

The compound (B) is a compound having a polymerizable carbon-carbon bond in the molecule, and the refractive index of the homopolymer of the compound is different from the refractive index of the homopolymer of the compound (A).
The haze value of the obtained light control film increases as the difference in refractive index between the homopolymer of compound (A) and the homopolymer of compound (B) increases. The difference in refractive index between the homopolymer of compound (A) and the homopolymer of compound (B) is usually 0.01 or more, preferably 0.02 or more.
Three or more compounds having a polymerizable carbon-carbon bond in the molecule may be used in the composition of the present invention, and in that case, the difference in refractive index between any two homopolymers of those compounds may be different. That's fine.
The mixing ratio of the compounds having a refractive index difference of 0.01 or more is usually in the range of (A) :( B) = 10: 90 to 90:10 by weight ratio. Further, it is preferable that the compatibility of the compounds (A) and (B) is somewhat low.

Compounds (A) and (B) include monomers and oligomers.
Examples of the monomer include tetrahydrofurfuryl acrylate, ethyl carbitol acrylate, dicyclopentenyloxyethyl acrylate, phenyl carbitol acrylate, nonylphenoxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and ω-hydroxyhexanoyloxyethyl. Acrylate, acryloyloxyethyl succinate, acryloyloxyethyl phthalate, isobornyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, phenyl carbitol acrylate, nonylphenoxyethyl acrylate, 2 -Hydroxy-3-phenoxypropyl acrylate, 2,4,6-tribromofe One polymerizable carbon-carbon double bond in the molecule such as xylethyl acrylate, 2,4,6-tribromophenyl acrylate, N-vinyl pyrrolidone, N-acryloyl morpholine, and methacrylate monomers corresponding to these acrylates. A compound having,

  For example, triethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, hydrogenated dicyclopentadienyl diacrylate, trimethylolpropane triacrylate, pentaerythritol hexaacrylate, ethylene Oxide-modified bisphenol A diacrylate, trisacryloxy isocyanurate, polyfunctional epoxy acrylate, polyfunctional urethane acrylate, methacrylates corresponding to these acrylates such as diethylene glycol bisallyl carbonate, divinylbenzene, triallyl isocyanurate Compound having a plurality of polymerizable carbon-carbon double bonds

  Examples of the oligomer include polyfunctional acrylates such as polyester acrylate, polyol polyacrylate, modified polyol polyacrylate, isocyanuric acid skeleton polyacrylate, melamine acrylate, hydantoin skeleton polyacrylate, polybutadiene acrylate, epoxy acrylate, urethane acrylate, and the like. And methacrylates corresponding to the acrylates. As a urethane acrylate oligomer, what is produced | generated by addition reaction of polyisocyanate, a polyol, and 2-hydroxyalkyl (meth) acrylate is illustrated. Here, examples of the polyisocyanate include toluene diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate. Examples of the polyol include polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The compound (C) of the present invention is a compound having a structure represented by the following (I) in the molecule and containing no polymerizable carbon-carbon bond.

In the formula, R ₁ represents a hydrocarbon group having 1 to 12 carbon atoms. Here, examples of the hydrocarbon group include linear alkyl groups having 1 to 12 carbon atoms such as a methyl group, an ethyl group, and an n-propyl group, such as a t-butyl group, a t-amyl group, and 2- A branched alkyl group having 4 to 12 carbon atoms such as ethylhexyl group, for example, a cycloalkyl group having 5 to 8 carbon atoms such as cyclopentyl group and cyclohexyl group, for example, 6 to 12 carbon atoms such as 1-methylcyclohexyl group Examples thereof include alkylcycloalkyl groups such as aromatic groups having 6 to 12 carbon atoms such as phenyl group and benzyl group. As R ₁ , a branched alkyl group is preferable, and in particular, it is preferable because preparation of a t-butyl group is easy.
R ₂ represents a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom; a hydrocarbon group exemplified above; an alkoxy group having 1 to 12 carbon atoms such as a methoxy group or an ethoxy group; an amino group, methylamino Represents an amino group which may be substituted, such as a group, a dimethylamino group, an ethylamino group and a diethylamino group; The hydrocarbon group and the alkoxy group may be substituted with a halogen atom or the like. R ₂ is preferably a hydrogen atom or an alkyl group.

As the structure (I) excluding X, the following formula is exemplified.

X contained in the structure (I) represents a hydrocarbon group having 1 to 12 carbon atoms, an alkylidene group having 1 to 4 carbon atoms, or a sulfur atom (—S—).
Here, the hydrocarbon group is, for example, a linear, branched or cyclic alkyl group such as a methyl group, an ethyl group, an n-propyl group, a t-butyl group, or a 2-ethylhexyl group, such as a phenyl group. And aromatic groups such as a benzyl group. Of these, an alkyl group is preferable, and a branched alkyl group is particularly preferable.
The alkylidene group represents a divalent group derived by removing one hydrogen atom from a carbon atom having a free valence of a monovalent alkyl group. Specifically, a methylene group (CH ₂ = ), An ethylidene group (CH ₃ CH =), an isopropylidene group ((CH ₃ ) ₂ CH =), a butylidene group (CH ₃ CH ₂ CH ₂ CH =), and the like.
In the ultraviolet absorber, the X site has a benzotriazole structure or a carbonyl structure, but the component (C) of the present invention contains the X site, so that the composition of the present invention can be obtained without absorbing ultraviolet rays. It can be photocured quickly.

  X represents, for example, a carbonyl group, an ether group, an ester group, a sulfide group, a sulfonyl group, a hydrocarbon group, for example, an alkylene group such as a methylene group or an ethylene group, for example, an alkylidene group similar to the above, for example, a bonding group such as a direct bond It couple | bonds with the structure represented by a formula (II), a C1-C12 hydrocarbon group, etc. through these. The linking group may be a linking group in which the exemplified linking groups are combined, or a plurality of structures of formula (II) and hydrocarbon groups may be bonded.

式中、Ｒ_３はＲ_１と同じ意味を表し、Ｒ_４は、Ｒ_２と同じ意味を表す。Ｒ_１〜Ｒ_４は互いに同一でも異なっていてもよい。

In the formula, R ₃ represents the same meaning as R _1, and R ₄ represents the same meaning as R ₂ . R _{1 to} R ₄ may be the same as or different from each other.

Compound (C) may be a mixture of different compounds.
Examples of the compound (C) include 2,6-Di-tert-butyl-4-methylphenol, n-Octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2′- Methylenebis (4-methyl-6-tert-butyl phenol), Tetrakis [methylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 3,9-Bis [2- [3- ( 3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4'-Butylidenebis (3- methyl-6-tert-butylphenol), 4,4′-Thiobis (3-methyl-6-tert-butylphenol) and the like.
Among them, 2,6-Di-tert-butyl-4-methylphenol is preferable because it has an angle range that gives a sufficiently low haze and a large angle range that gives a high haze.

  Content of the compound (C) in the composition of this invention is 0.01-10 weight part normally with respect to 100 weight part of compositions, Preferably it is 0.02-5 weight part. When the compound (C) is 0.01 part by weight or more, it is preferable because the angle range of a high haze value tends to be expanded. When the content is increased, the solubility becomes poor, so the content is 10 parts by weight or less. Preferably there is.

  In addition to the compounds (A), (B) and (C), the composition of the present invention may be, for example, polystyrene, polymethyl methacrylate, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol, nylon, etc. Polymers such as toluene, n-hexane, cyclohexane, methyl alcohol, ethyl alcohol, acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, dimethylformamide, dimethylacetamide, acetonitrile, etc., organic halogen compounds, organosilicon compounds, plastics Plastic additives such as agents and stabilizers may be contained.

The light control film of the present invention is obtained by curing the composition of the present invention. As a method for producing the light control film, a method of applying the composition of the present invention on a substrate such as a glass plate or a polyethylene terephthalate plate and photocuring it. For example, a method of encapsulating the composition of the present invention in a cell and photocuring it may be mentioned.
The composition before photocuring is usually photocured in the form of a film having a thickness of about 25 μm to 1000 μm, a width of 5 cm to 300 cm and a length of 5 cm to several hundred m.

A composition in which oxygen is blocked, such as a composition obtained by encapsulating in a cell, does not necessarily require a photopolymerization initiator, but in a general method such as a method of coating on a substrate, In order to improve the degree of curing, a film-like composition in which a photopolymerization initiator is mixed in advance is used.
Examples of the photopolymerization initiator include benzophenone, benzyl, Michler ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin methyl ether, benzoin ethyl ether, diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methyl. Examples include propiophenone and 1-hydroxycyclohexyl phenyl ketone.
When the photopolymerization initiator is mixed, the mixing amount is usually about 0.01 to 5 parts by weight, preferably about 0.1 to 3 parts by weight with respect to 100 parts by weight of the film-like composition.

Photopolymerization For example, as in the ultraviolet curing device of FIG. 1, a film-like composition 1 is applied on a glass plate by irradiating light from a rod-like light source 5 as a light beam in the vertical direction through the slit 4 of the light shielding plate 3. And the like, and a method of gradually curing while moving at a speed of about 0.01 to 10.0 m / min, preferably about 0.1 to 5.0 m / min.
Examples of the ultraviolet light source include light sources such as high-pressure mercury lamps and metal halide lamps. The shape of the light source is a simple rod-shaped light source, a series of many point light sources arranged in a line, laser light, etc. A linear light source such as a light source that scans light using a rotary mirror and a concave mirror (irradiates while moving linearly from a number of different angles at one point of the irradiated position) is used. Among these, a rod-shaped light source is preferable because it is easy to handle.

  The film-like composition exhibits anisotropy with respect to the major axis and the minor axis direction of the light source, and scatters light at a specific angle only when the film-like composition is moved in the minor axis direction of the light source. That is, the film-like composition forms a microstructure layer in which regions having different refractive indexes periodically exist in a state of being oriented in parallel with the long axis direction of the light source. Thus, it is considered that light incident on the light control film of the present invention from a specific angle is scattered in regions having different refractive indexes.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these examples.

  The haze value is obtained by using an integrating sphere type light transmittance measuring device (Hazeguard Plus 4725 manufactured by Gardner) and setting the distance between the center of the light control film and the integrating sphere to 4 cm, and the total light transmittance and diffusion of the light control film. It is a value determined by measuring the transmittance and using the following equation.

  Further, the angle dependency of the haze value in the light control film was measured as follows. That is, as shown in FIG. 2, the angle θ of the incident light to the test piece 6 of the light control film is changed between 0 to 180 °, and the above-described haze value is measured for each angle. Here, the angle θ is a value in which the direction parallel to the surface of the test piece 6 is 0 ° and the normal direction of the test piece 6 is 90 °. The rotation of the test piece 6 depends on the angle dependency of the haze value. In the direction that maximizes. A and B in the figure are the left figure (when light enters the test piece 6 from the vertical direction: θ = 90 °) and the right figure (when light enters the test piece 6 from an oblique direction) Thus, the reference numerals are attached so that the corresponding portions of the test piece 6 can be seen.

Example 1
Based on polypropylene glycol having an average molecular weight of about 3,000 and 40 parts by weight of polyether urethane acrylate (refractive index: 1.460, compound (B)) obtained by reaction of toluene diisocyanate hexamethylene diisocyanate with 2-hydroxyethyl acrylate 2,4,6-tribromophenyl acrylate (I) 30 parts by weight (compound (A)), 2-hydroxy-3-phenoxypropyl acrylate (II) 30 parts by weight (refractive index 1.526, compound (A) ) And 2-hydroxy-2-methylpropiophenone (polymerization initiator) mixed with 1.5 parts by weight of 2,6-di-t-butyl-4-methylphenol (compound (C A composition obtained by adding 2.0 parts by weight of)) and thoroughly mixing it was applied on a glass plate to a thickness of 220 μm. An 80 W / cm rod-shaped high-pressure mercury lamp was placed at a position 50 cm above the obtained film-shaped composition, and passed through a light-shielding plate with a slit so that the entire surface of the coating film was exposed to light, 0.6 m / min. Light was irradiated while moving the glass plate with a coating film laterally at a speed (see FIG. 1) to obtain a light control film. The dependence of the haze value on the incident light angle was measured as shown in FIG. From the obtained angle-dependent haze curve (Fig. 3), the maximum haze value (%), the haze value of the haze value of 40% or more is used as the opacity angle range (°) and the haze value at an incident angle of 120 °. It is shown in Table 1.

(Example 2, Comparative Examples 1-3)
A light control film was obtained in the same manner as in Example 1 except that the compounds (VI to VIII) described below were used as the compound not containing a polymerizable carbon-carbon bond. The results are shown in Table 1.
In Comparative Example 2, the photopolymerizable composition was not photocured and a light control film could not be obtained. In Comparative Example 3, the results of the light control film obtained without using a compound containing no polymerizable carbon-carbon bond are shown in Table 1.

  The photopolymerizable composition of the present invention is photocured at a speed equivalent to the case where the compound (C) is not added, and the light control film of the present invention has a wide opacity angle range and a high haze value. That is, a lot of incident light is scattered. Further, the light control film of the present invention has a transparent angle region through which incident light is transmitted with a haze of 5% or less.

  The light control film of the present invention can be used even if it is coated or bonded to a transparent substrate such as a glass plate or other plastic sheet. Then, the obtained laminate of the transparent base material and the light control film is used for optical films such as building material windows, vehicle windows, mirrors, greenhouse outer wall materials, flat panel displays, and rear projection displays. Can do.

i: Side view of ultraviolet curing device ii: Perspective view of ultraviolet curing device Schematic diagram of haze angle dependence measurement method Haze value curves of Examples and Comparative Examples

Explanation of symbols

1. Laminated body of film-shaped resin composition and glass substrate,
2 ... conveyor,
3 …… Shading plate,
4 ... Slits provided on the light shielding plate,
5 ... Bar light source lamp (high pressure mercury lamp),
6. Test piece for measuring haze value (light control film)

Claims (6)

A composition comprising the following compounds (A) to (C):
(A): Compound having a polymerizable carbon-carbon bond in the molecule (B): Compound having a polymerizable carbon-carbon bond in the molecule, wherein the refractive index of the homopolymer of the compound is compound (A) Compound (C) different from the refractive index of the homopolymer of: a compound having a structure represented by the following (I) in the molecule and not containing a polymerizable carbon-carbon bond:

(Wherein R ₁ represents a branched hydrocarbon group having 4 to 12 carbon atoms, and R ₂ represents a hydrogen atom, a halogen atom, an optionally substituted hydrocarbon group having 1 to 8 carbon atoms, or a substituted group. And represents an optionally substituted alkoxy group and an optionally substituted amino group, and X represents a hydrocarbon group having 1 to 12 carbon atoms, an alkylidene group having 1 to 4 carbon atoms, or a sulfur atom.) 2. The composition according to claim 1, wherein R ₁ of the compound (C) is a branched alkyl group having 4 or more carbon atoms.   Compound (C) is 2,6-Di-tert-butyl-4-methylphenol, n-Octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,2'-Methylenebis (4 -methyl-6-tert-butyl phenol), Tetrakis [methylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 3,9-Bis [2- [3- (3-tert -butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, 4,4'-Butylidenebis (3-methyl-6 -tert-butylphenol) and 4,4'-Thiobis (3-methyl-6-tert-butylphenol), at least one compound selected from the group consisting of Composition.   The refractive index difference between the homopolymer of the compound (A) and the homopolymer of the compound (B) is 0.01 or more, and is a combination of the compound (A) and the compound (B). 4. The composition according to any one of 3.   The composition according to any one of claims 1 to 3, wherein the composition further contains a polymerization initiator. A light control film obtained by photocuring the composition according to claim 1.

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