JPH0254201A - Resin composition for light control plate - Google Patents

Abstract

PURPOSE:To provide the resin compsn. which has the uniform quality to selectively scatter only the incident light of a specific angle, high scattering power and good weatherability by incorporating acrylate monomers and urethane acrylate oligomer which are respectively specific into the compsn. CONSTITUTION:One or more kinds of the acrylate monomers which have no halogen atoms in the molecule and the urethane acrylate oligomer having >=1,000 mol.wt. are incorporated into this compsn. The light control plate which sufficiently withstands outdoor use as building materials, etc., is then obtd. merely by compounding this compsn. with various transparent films and plastic having a light degree of UV light cutting power, etc., without the need for using various additives. The light control plate which has the uniform quality to selectively scatter only the incident angle of the specific angle, the high scattering power and the good weatherability is obtd. in this way by the relatively simple method.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a resin composition for a light control plate that selectively scatters only incident light from a specific angle.

<Prior art and its problems> Conventionally, transparent bodies made of plastic or glass were only transparent to light from any angle. Therefore, as a material that only transmits light from a specific angle, an alignment film cut out from a plastic block made by laminating plastic transparent sheets and opaque sheets alternately, or a grid or stripe on a transparent substrate using photosensitive resin. A so-called "light-shielding plate" was used optically, in which a relief with a pattern such as the above was provided, and a transparent substrate or the like was placed on top of the relief. As this light shielding plate, for example, there is one shown in Japanese Patent Application Laid-Open No. 57-189439. However, these conventional alignment films and light shielding plates have problems in that they are expensive due to complicated manufacturing methods and that the film quality is not uniform. In contrast, by curing multiple polymerizable compounds with different refractive indexes under specific ultraviolet curing conditions, it is extremely easy to create a uniform film that selectively scatters only incident light from specific angles. A manufacturing method for obtaining a control board has been proposed. This light control board requires high scattering for incident light from a specific angle, for example 80% or more in terms of haze value, while high transparency for incident light from other angles. . However, conventional resin compositions for light control boards often use (meth)acrylate monomers containing halogen atoms with a large refractive index in order to increase the difference in refractive index between monomer oligomers and obtain high haze. Ta.

When such a (meth)acrylate monomer having a halogen atom is used, the resulting film undergoes desorption of the halogen atoms in the molecule when heated or irradiated with ultraviolet light including sunlight, resulting in significant yellowing. Regarding its weather resistance,
It was very bad.

However, the applications in which such light control boards may be used include building materials, automobile parts, and decorative items, and in all of these applications, the materials used must have severe weather resistance. is always the case. Therefore, when using it as a light control plate, it is necessary to combine it with various transparent films or plastics that have extremely high ultraviolet light cutting ability, and also to use additives such as noherogen stabilizers and ultraviolet absorbers. Met.

The present inventor has devised a resin composition for a light control board that has a uniform film quality that selectively scatters only incident light forming a specific angle, the film has a high scattering ability and is weather resistant. As a result of research to find something good, the present invention was completed.

Means for Solving the Problems> That is, the present invention is characterized by: ◎ containing one or more types of (meth)acrylate monomers that do not have a halogen atom in the molecule; and (A) a urethane acrylate oligomer having a molecular weight of 1000 or more. This is a resin composition for a light control board.

Examples of the urethane acrylate oligomer (A) include those produced by addition reaction of polyisocyanate, 2-hydroxyalkyl (meth)acrylate, and polyol. Here, examples of the polyisocyanate include toluene diisocyanate, inphorone diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, and the like. Examples of polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, polyester polyols, and polysiloxane polyols.In addition, these polyols and 3-methylbentanediol, 1,4-butanediol, Combination use with low molecular weight components such as thiogentanol may also be mentioned.

These urethane acrylate compounds require a molecular weight of 1000 or more in order to exhibit high scattering ability when the resin composition is used as a light control plate.

These compounds usually have a refractive index of 1.5 or less and are also characterized by extremely excellent polymerizability.

The compound (B) is an acrylate monomer having a refractive index of 1.51 or more, such as phenyl acrylate, benzyl acrylate, or a phenyl glycidyl ether acrylic acid adduct, or a methacrylate monomer corresponding to these acrylates.

In order for the light control plate using these compounds to have high scattering ability, it is necessary that the refractive index difference between the monomer component and the oligomer component be 0.01 or more, preferably 0.02 or more. .

Two or more kinds of compounds (A) and CB) may be used in combination.

The present composition is an ultraviolet curable resin composition for a light control board, and the composition ratio of (A) is 10 to 90% by weight, preferably 30 to 70% by weight, based on the total weight of [A] + CB). It is. By curing such a composition with an ultraviolet curing device as shown in Figure 1, a light control plate that selectively scatters incident light at a specific angle is created. In addition, performance expression (
It is also possible to use a thermosetting mechanism in combination without causing any problems.

For curing, it is preferable to apply the composition onto a substrate or encapsulate it in a cell, and then irradiate the composition with ultraviolet rays from a specific direction to cure it. By this method, it is possible to create a light control plate that selectively scatters incident light at a desired angle. Further, a photopolymerization initiator is not necessarily required if it can be sealed in a cell to block 02, but in order to improve curability, it is preferable to add the following photopolymerization initiator.

For example, benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, jetoxyacetophenone, benzyl dimethyl ketal, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclo Examples include xylphenyl ketone.

<Effects of the Invention> The composition of the present invention exhibits a high degree of scattering when used as a light control plate, and also has high weather resistance, so there is no need to use various additives, and the composition of the present invention does not require the use of various additives. It is possible to obtain a light control board that is sufficiently durable for outdoor use as a building material, simply by combining it with various transparent films or plastics that have the ability to cut ultraviolet light. That is, according to the present invention, it is possible to manufacture a light control plate with a uniform film quality that selectively scatters only incident light forming a specific angle using a relatively simple method, which has high scattering ability and good weather resistance. became possible.

The light control plate made of the resin composition of the present invention is a plastic sheet, but it can also be used by coating a glass plate or other plastic sheet. These products can be used in a variety of applications, including window materials, vehicles, displays, mirrors, and greenhouses.

<Examples> The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 60 parts for 40 parts of polyether urethane acrylate (refractive index 1.467) obtained by the reaction of polypropylene glycol with an average molecular weight of 96,000, toluene diisocyanate and 2-hydroxyethyl acrylate, and 2-hydroxy-2- Using a methyl-30W mercury lamp ultraviolet irradiation device, the distance was 40 cm as shown in Figure 1.
UV rays were irradiated for 0.5 minutes to obtain a cured film, and the dependence of the angle of incident light on the tatami was measured as shown in Figure 2. Furthermore, an accelerated weathering test was conducted using a DuPanel light control weather meter, and the deterioration of yellowing over time was measured using a color difference meter. For haze value and yellowing change, the values are shown in the table.
II shows this.

Example 2 A resin composition prepared by adding and mixing 3 parts of polyether hydroxy-2-methylpropiophenone obtained by the reaction of polytetramethylene glycol having an average molecular weight of 2000, #dimethylhexamethylene diisocyanate, and 2-hydroxyethyl acrylate. was cured in the same manner as in Example 1 to obtain a cured sheet, and the physical properties were measured in the same manner as in Example 1. The results are shown in Table-1.

Example 3 Polytetramethylene glycol with an average molecular weight of 2000,
60 parts of the compound CI shown in Example 1 and 2-hydroxy-2 to 40 parts of polyether urethane acrylate (RI=1.476) obtained by the reaction of inphorone diisocyanate and 2-hydroxyethyl acrylate. - A resin composition containing 3 parts of methylpropiophenone was cured in the same manner as in Example 1 to obtain a cured sheet, and the physical properties were measured in the same manner as in Example 1. The results are shown in Table-1.

Example 4 Same polyether urethane acrylate 40 as Example 1
phenyl acrylate (refractive index 1.521
) and 3 parts of 2-hydroxy-2-methylpropiophenone were added and mixed to obtain a cured sheet and cured in the same manner as in Example 1, and the physical properties were measured in the same manner as in Example 1. Shitco. The results are shown in Table-1.

Comparative Example Polytetramethylene glycol with an average molecular weight of 2000,
The results are shown in Table 1 for 30 parts of polyether urethane acrylate obtained by the reaction of toluene diisocyanate and 2-hydroxyethyl acrylate.

Table 1 and a resin composition in which 3 parts of 2-hydroxy-2-methyl-propiophenone were added and mixed were cured in the same manner as in Example 1 to obtain a cured sheet, and the physical properties were measured in the same manner as in Example 1. did.

[Brief explanation of the drawing]

FIG. 1 shows a side view and a plan view of the ultraviolet irradiation device used in Examples and Comparative Examples. Figure 2 shows the method for measuring haze value in Examples and Comparative Examples.

Claims (1)

[Claims] A resin composition for a light control board, comprising a (meth)acrylate monomer having no halogen atom in the molecule and a urethane acrylate oligomer having a molecular weight of 1000 or more.