JPH03107901A - Production of light control plate - Google Patents

Abstract

PURPOSE:To obtain the light control plate which selectively scatters only the incident light from a specific angle by casting a specific compd. or coating the surface of a substrate with this compd., then irradiating the compd. with active rays from a specific angle, thereby curing the compd. CONSTITUTION:The compd. having plural polymerizable carbon-carbon double bonds in the molecule is cast or the substrate is coated with this compd. and thereafter, the compd. is irradiated with the active rays from the specific angle and is thereby cured. The compd. to be used is a monomer or oligomer having >=2 pieces of polymerizable groups, such as acryloyl groups, methacryloyl groups, vinyl groups or allyl groups in the molecule and the difference in the refractive index before and after the curing is >=0.01. The light control plate which selectively scatters only the incident light forming the specific angle and allows the transmission thereof is obtd. from the single compd. in this way.

Description

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

<Conventional technology> Conventional 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, there is an alignment film cut out from a plastic block made by laminating plastic transparent sheets and opaque sheets alternately, and a checkered or striped film made of photosensitive resin on a transparent substrate. A so-called "light-shielding plate" was commonly used, in which a relief with a pattern such as the above was provided, and a transparent substrate or the like was further placed on top of the relief. As this light shielding plate, for example, there is one shown in Japanese Patent Laid-Open No. 189439/1983.

<Problems to be Solved by the Invention> However, these conventional alignment films and light shielding plates have problems in that they are expensive due to complicated manufacturing methods, and 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 control light to create a uniform film that selectively scatters only incident light from specific angles. A manufacturing method for obtaining a plate is proposed, for example, in Japanese Patent Application Laid-Open No. 63-309902.

However, this light control plate requires a plurality of compounds having one or more polymerizable carbon-carbon double bonds in the molecule and having different refractive indexes as raw materials.

The present inventor completed the present invention after studying to find a single compound that selectively scatters and transmits only incident light forming a specific angle.

Means for Solving the Problems> That is, the present invention provides a compound having multiple polymerizable carbon-carbon double bonds in the molecule, and the difference in refractive index before and after curing is 0.
．． 01 or more is cast or coated on a substrate,
The present invention provides a method for producing a light control board, which comprises curing the compound by irradiating the compound with actinic rays from a specific angle.

The present invention will be explained in detail below.

The compound used in the present invention is a monomer or oligomer containing two or more polymerizable groups such as acryloyl group, methacryloyl group, vinyl group, or allyl group in the molecule, and the difference in refractive index before and after curing is 0. .01 or more. Specifically, for example, triethylene glycol diacrylate, polyethylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanesiol diacrylate, hydrogenated dicyclopentagenyl diacrylate, ethylene oxide modified bisphenol A diacrylate, Methylolpropane triacrylate, pentaerythritol hexaacrylate, trisacryloxyisocyanurate, multifunctional epoxy acrylate, multifunctional urethane acrylic sheet, methacrylates corresponding to these acrylates, divinylbenzene, triallylisocyanurate, diethylene glycol bis Examples include allyl carbonate.

In order for a light control plate using these compounds to have sufficient scattering ability, the difference in refractive index before and after curing of these compounds must be 0.
．． 01 or more, preferably 0.02 or more. Although these compounds can be used alone to produce a light control board, they may be used in combination with other compounds.

The compound used in the present invention is a photocurable compound.
By curing with a photocuring device as shown in 1, a light control plate that selectively scatters incident light at a specific angle is created. For curing, the compound is coated onto a substrate by means such as casting or coating, or cast, for example, sealed in a cell, and then irradiated with light from a specific direction to be cured. This method makes it possible to create a light control plate that selectively scatters incident light at a desired angle.

Here, as the active light, visible light, ultraviolet light, or the like that causes a polymerization reaction is used, and ultraviolet light is particularly preferably used. Examples of the photopolymerization initiator used as necessary include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, jetoxyacetophenone, benzyl dimethyl ketal, 2-
Examples include hydroxy-2-methylpropiophenone and l-hydroxycyclohexylphenyl ketone.

The light source used in photopolymerization emits active rays such as ultraviolet rays that contribute to photopolymerization, and the light source has a linear shape when viewed from the irradiated position (film surface).
A rod-shaped lamp is one of the preferred linear illumination sources.

When a linear light source is used and the irradiation conditions are adjusted, the resulting sheet-like cured material exhibits anisotropy in the long and short axis directions of the light source, and when rotated around the long axis of the light source, It only scatters light at a specific angle.

In other words, in the produced sheet-like cured polymer, regions with different refractive indexes exist periodically in a state oriented in a certain direction, and light incident from a specific angle is completely absorbed at the boundary between the regions with different refractive indexes. It is thought that it is reflected and scattered.

This region with different refractive index is thought to be generated due to the difference in the degree of curing of the compound used in the present invention, and the larger the difference in refractive index due to the degree of curing, the greater the light scattering ability of the produced light control plate. is expected to increase. Therefore, even for compounds having only one polymerizable carbon-carbon double bond in the molecule and compounds having multiple polymerizable carbon-carbon double bonds in the molecule, the difference in refractive index before and after curing is 0.0.
Compounds with a hardness of 1 or less are considered not to have sufficient scattering ability because it is difficult to create a difference in refractive index due to a difference in degree of curing.

<Effects of the Invention> In the present invention, it has become possible to manufacture a light control plate that selectively scatters only incident light at a specific angle, which conventionally required multiple polymerizable compounds, using a single polymerizable compound. .

The light control plate obtained by the present invention is in the form of 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. In addition,
"Parts" in the examples mean "parts by weight."

Example 1 A composition prepared by adding and mixing 3 parts of 2-hydroxy-2-methyl-propiophenone to 100 parts of trimethylolpropane triacrylate was coated on a glass plate to a thickness of 200 μm, and heated with a 30 W mercury lamp. Using an ultraviolet irradiation device, ultraviolet rays were irradiated for 1 minute at a distance of 40 cm as shown in Figure 1 to obtain a cured film. Figure 2 shows the dependence of the haze value on the incident light angle.
The results of the measurements are shown in Table 1.

Example 2 2- to 100 parts of compound (I) represented by the following structural formula
A composition containing 3 parts of hydroxy-2-methyl-propiophenone was polymerized and cured in the same manner as in Example 1 to obtain a cured sheet, and clouding was measured in the same manner as in Example 1.

The results are shown in Table-1.

Example 3 Epoxy acrylate (rl)i represented by the following structural formula
A composition prepared by adding and mixing 3 parts of CHlhOCOCH:Ct(2(II)l-hydroxycyclohexylphenylketone to oo part) was polymerized and cured in the same manner as in Example 1 to obtain a cured sheet. Table 1 shows the results of measuring the haze value.
Shown below.

Example 4 Composition in which 3 parts of 2-hydroxy-2-methy"-propiophenone was added and mixed with 100 parts of urethane acrylate obtained by reacting 1 mol of hexamethylene diisocyanate with 2 mol of pentaerythritol triacrylate. The material was cured in the same manner as in Example 1 to obtain a cured sheet, and the haze value was measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 A resin composition prepared by adding and mixing 3 parts of H2-hydroxy-2-methyl-propiophenone to 100 parts of compound (II[) represented by the following structural formula was cured in the same manner as in Example 1. A sheet was obtained, and the haze value was measured in the same manner as in Example 1. The results are shown in Table-1.

Comparative Example 2 2-hydroxy-2-methyl- to 100 parts of polyether urethane acrylate obtained by reacting polypropylene glycol with an average molecular weight of 3000, toluene diisocyanate, and 2-hydroxyethyl acrylate.
Example 1 A composition containing 3 parts of propiophenone was added and mixed.
A cured sheet was obtained by curing in the same manner as in Example 1, and the haze value was measured in the same manner as in Example 1. The results are shown in Table 1.

Table-1

[Brief explanation of drawings]

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 compound that has multiple polymerizable carbon-carbon double bonds in its molecule and has a refractive index difference of 0.01 or more before and after curing is cast or coated on a substrate, and then actinic light is irradiated from a specific angle. A method for producing a light control board, comprising curing the compound by irradiating the compound.