JP2001215456A - Thermosensitive light transmission control material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive light transmission control material which is a material to allow the transmission of light and to shut off light autonomously by a temperature change, for example, is used for light controllable grass. SOLUTION: This thermosensitive light transmission control material consists of a polymer containing a polyalkylene glycol group, water and/or a polar solvent exclusive of water. The material is transparent below a specific temperature and turns turbid above the specific temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature-sensitive light transmission control material which can be used for a light control glass or the like and controls a light transmittance by a change in temperature.

[0002]

2. Description of the Related Art In recent years, techniques for utilizing light have been developed in fields such as optical information processing and optical applied measurement, and the need to control light intensity and light transmittance has emerged. Also, in recent years, under the concept of environmental harmony, there has been a demand for comfortable and energy-saving windows that make effective use of the sun's rays, and there is a need for dimming glass that can reversibly change and block light. As materials for realizing these, there are liquid crystal (JP-A-1-62615), electrochromic and photochromic materials (JP-A-2-85274), but there is a demand for a temperature-sensitive light transmission control material that can be more easily controlled. Is increasing. As a temperature-sensitive light transmission controlling material, a polymethacrylic acid-containing gel (JP-A-59-214018), a polyvinyl methyl ether gel, and the like have been proposed.

[0003]

The polymethacrylic acid hydrogel and the polyvinyl methyl ether gel have a problem in that the characteristic temperature for transmitting and blocking light cannot be arbitrarily controlled.

An object of the present invention is to provide a temperature-sensitive light transmission controlling material capable of arbitrarily controlling the temperature at which light is transmitted and blocked by changing the composition of a polymer.

[0005]

SUMMARY OF THE INVENTION The present invention is a temperature-sensitive light transmission control material comprising a polymer having a polyalkylene glycol group and water and / or a polar solvent other than water.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature-sensitive light transmission control material capable of reversibly changing optical characteristics, that is, light transmittance, at a characteristic temperature.

The present invention is a temperature-sensitive light transmission controlling material comprising a polymer containing a polyalkylene glycol group and water and / or a polar solvent other than water, which is transparent below the characteristic temperature and opaque above the characteristic temperature.

The above materials are transparent below the characteristic temperature, but become cloudy above the characteristic temperature. From this, light can be transmitted below the characteristic temperature, and blocked above the characteristic temperature. That is, light transmission can be controlled autonomously by a temperature change.

The light transmittance changes at the characteristic temperature because the material of the present invention shows a sol-gel transition at the characteristic temperature. . Below the characteristic temperature, the polyalkylene glycol group contained in the polymer is hydrated (solvated) in water and / or a polar solvent other than water, so that the polymer is dissolved in the solvent. Dehydration (desolvation) due to a change in entropy of the molecular chain due to thermal motion reduces the solubility of the polymer in the solvent, and increases the hydrophobic interaction between the polymers, causing the molecules to aggregate and gel. It is thought to happen.

The polyalkylene glycol group contained in the polymer in the temperature-sensitive light transmission controlling material of the present invention is represented by the following formula (1).

-(C _m H _2m O) _n -R (1) (R: H and a hydrocarbon group, m is an integer of 1 or more, n
Is an integer of 2 or more.) The polymer contained in the thermosensitive light transmission controlling material of the present invention can be obtained by copolymerizing a polyalkylene glycol group-containing ethylenic monomer with another copolymerizable ethylenic monomer.

The polyalkylene glycol group-containing ethylenic monomer used for synthesizing the polymer contained in the temperature-sensitive light transmission controlling material of the present invention is, for example, polyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethoxy, etc. Polyethylene glycol (meth) acrylate, propoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, ethoxy polypropylene glycol ( (Meth) acrylate, propoxy polypropylene glycol (meth) acrylate, butoxy Polypropylene glycol (meth)
Acrylate, phenoxy polypropylene glycol (meth) acrylate, polymethylene glycol (meth) acrylate, methoxypolymethylene glycol (meth) acrylate, ethoxypolymethylene glycol (meth) acrylate, propoxypolymethylene glycol (meth) acrylate, butoxypolymethylene glycol ( (Meth) acrylate, phenoxypolymethylene glycol (meth) acrylate butylene, polyglycol (meth) acrylate, methoxypolybutylene glycol (meth) acrylate, ethoxypolybutylene glycol (meth) acrylate, propoxypolybutylene glycol (meth) acrylate, butoxypoly Butylene glycol (meth) acrylate, phenoxypolybutylene glycol ( Data) is an acrylate, and the like.
Preferably, m = 1-6 and n = 2-15.

Other copolymerizable ethylenic monomers used in synthesizing the polymer contained in the temperature-sensitive light transmission controlling material of the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate.
Acrylate, (meth) acrylonitrile, glycidyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2
-Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) A) acrylate, perfluorocyclohexyl (meth) acrylate, styrene, vinyltoluene, ethylstyrene, p-chlorostyrene and other hydrophobic group-containing ethylenic monomers, 2-hydroxyethyl (meth)
Hydroxyl-containing ethylenic monomers such as acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; acrylic acid, methacrylic acid, itaconic acid, maleic acid, 3-vinylsalicylic acid, 3-vinylacetylsalicylic acid; acidic group-containing ethylenic monomer such as p-vinylbenzenesulfonic acid or 2-acrylamidopropanesulfonic acid, (meth)
Acrylamide, N-methyl (meth) acrylamide,
Examples include amide group-containing ethylenic monomers such as N, N-dimethyl (meth) acrylamide and N-butoxymethyl (meth) acrylamide.

In particular, it is preferable to copolymerize a hydrophobic group-containing ethylenic monomer and a hydroxyl group-containing ethylenic monomer in order to control the transmission and blocking of light.

The number average molecular weight of the polymer contained in the thermosensitive light control material of the present invention is 500,000.
It is preferred that: The above molecular weight is 500,000
If it exceeds, the mobility of molecules deteriorates, and as a result, the response of transmitting and blocking light at a characteristic temperature deteriorates.

Preferred conditions for copolymerization for preparing the polymer contained in the temperature-sensitive light control material of the present invention will be described.

The copolymer corresponding to the polymer in the present invention can be prepared by mixing a monomer in a reaction vessel with a polymerization initiator such as an azo compound or an organic peroxide in the presence of an organic solvent in an amount of 50 to 150. It is obtained by polymerizing at a temperature of ° C for 3 to 5 hours. Examples of the organic solvent include methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, toluene, xylene, benzene, dioxane, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol mono n-butyl ether, tetrahydrofuran and the like can be used. As the organic solvent, one of these solvents or a combination of two or more thereof can be used. As the azo compound, 2,2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobisisobutyrate and the like can be used. Benzoyl peroxide, t-butyl peroxybenzoate, t-
Butyl peroxyisobutyrate, t-butyl peroxy 2-ethylhexanoate, cumene hydroperoxide and the like can be used.

The amount of the ethylenic monomer containing a polyalkylene glycol group when synthesizing the polymer contained in the thermosensitive light control material of the present invention is preferably 1 to 80 mol%, and more preferably 5 to 70 mol%. Is more preferred.
If it is less than 1 mol%, it is difficult to disperse in water. If it exceeds 90 mol%, gelation is promoted, and the dispersibility of the polymer in water and / or a polar solvent other than water tends to decrease.

The characteristic temperature of the temperature-sensitive light transmission controlling material of the present invention can be controlled by changing the compounding ratio of the ethylenic monomer when synthesizing the polymer, for example, the compounding amount of the polyalkylene glycol group-containing ethylenic monomer. The smaller the value, the lower the characteristic temperature. Furthermore, the characteristic temperature becomes lower as the amount of the hydroxyl group-containing ethylenic monomer is smaller.

The polar solvent other than water contained in the temperature-sensitive light control material of the present invention includes methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, hexyl alcohol, ethylene glycol monomethyl ether. , Ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono t-butyl ether, ethylene glycol monohexyl ether,
Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol mono n-
Butyl ether, propylene glycol monoisobutyl ether, propylene glycol mono-t-butyl ether, propylene glycol monohexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol mono n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol Monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol mono n-butyl ether, ethyl acetate, butyl acetate, isobutyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone and the like can be mentioned.

The temperature-sensitive light transmission controlling material of the present invention is a material capable of autonomously controlling the light transmittance through a transparent-opaque transition (sol-gel transition) at a characteristic temperature. By changing the composition of the polymer, it is easier to control the characteristic temperature as compared with the conventional temperature-sensitive light transmission control material, for example, a greenhouse, a chemical laboratory, a light control glass used in a radioisotope laboratory, a temperature sensor, Can be used for toys, interiors, displays, mechanochemical element materials, etc.

[0022]

The temperature-sensitive light transmission controlling material of the present invention can arbitrarily control the temperature at which the light transmittance changes by changing the composition of the polymer.

[0023]

EXAMPLES The present invention will be described in more detail with reference to Examples. The present invention is not limited to these examples. Example 1 Composition 1 82 parts by weight of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a temperature controller, and a reflux condenser, and the temperature was raised to 75 ° C. after purging with nitrogen. Here, methoxy polyethylene glycol methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.
Ester M-40G) 68 parts by weight, 2-hydroxyethyl methacrylate 6 parts by weight, n-butyl methacrylate 26
After adding a monomer solution consisting of parts by weight and 0.7 parts by weight of azobisisobutyronitrile over 3 hours, stirring was continued for 1.5 hours to obtain a polymer having a number average molecular weight of 17,000. (Example 2) Composition 2 82 parts by weight of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a temperature controller and a reflux condenser, and the temperature was adjusted to 75 ° C after purging with nitrogen. Here, methoxy polyethylene glycol methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.
Ester M-40G) 76 parts by weight, 2-hydroxyethyl methacrylate 6 parts by weight, n-butyl methacrylate 18
After a monomer solution consisting of parts by weight and 0.7 parts by weight of azobisisobutyronitrile was added over 3 hours, stirring was continued for 1.5 hours to obtain a polymer having a number average molecular weight of 18,000. (Example 3) Composition 3 A reaction vessel equipped with a stirrer, a temperature controller and a reflux condenser was charged with 82 parts by weight of methyl ethyl ketone, and the temperature was brought to 75 ° C after purging with nitrogen. Here, 37 parts by weight of methoxypolyethylene glycol methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester M-90G), 6 parts by weight of 2-hydroxyethyl methacrylate, 40 parts by weight of n-butyl methacrylate, 17 parts by weight of stearyl acrylate and azobisiso After adding a monomer solution consisting of 0.7 parts by weight of butyronitrile over 3 hours, stirring was continued for 1.5 hours to obtain a polymer having a number average molecular weight of 16,000. (Comparative Example 1) Polymer not containing polyalkylene glycol 82 parts by weight of isopropyl alcohol was charged into a reaction vessel equipped with a stirrer, a temperature controller and a reflux condenser, and the temperature was raised to 80 ° C after purging with nitrogen. Here, a monomer solution comprising 15 parts by weight of methacryl acrylate, 8 parts by weight of methacrylate, 24 parts by weight of 2-hydroxyethyl methacrylate, 53 parts by weight of n-butyl acrylate and 0.8 parts by weight of azobisisobutyronitrile was added for 5 hours. After the addition, stirring was continued for one and a half hours to obtain a number average molecular weight of 79.
00 resin was obtained. (Example 4) After desolvating the polymer of Example 1, Example 2, Example 3 and Comparative example 1 with an evaporator until the non-volatile content concentration became 80% by weight, Examples 1 to 3 were directly deionized water. In Comparative Example 1, an aqueous dispersion of a polymer having a non-volatile content of 25% by weight was prepared by adding deionized water after neutralization by equivalent weight with 2-dimethylaminoethanol. A sample was prepared by injecting between two glass plates. The temperature of this sample is kept at 20 ° C to 50 ° C in a thermostat.
The light transmittance when it was raised to was measured visually. Table 1 shows the results.

As shown in Table 1, at 20 ° C., Example 1
In Examples 2, 3 and Comparative Example 1, the polymer was sol-like and transparent, and light was transmitted. When the temperature was increased, Example 1 was between 28 ° C. and 32 ° C., and Example 2 was between 35 ° C. and 40 ° C.
Example 3 gels between 25 ° C and 30 ° C,
In contrast to the cloudiness, Comparative Example 1 maintained the sol state even when the temperature was increased, and was transparent. As a result, at 50 ° C., Examples 1, 2 and 3 were cloudy and no light was transmitted, whereas Comparative Example 1 was transparent and light was transmitted.

[0025]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C08L 55/00 C08L 55/00 F term (reference) 2H079 AA06 AA13 BA01 CA24 DA06 DA07 4J002 BQ001 DE026 EC036 ED026 EE036 EH036 HA04 HA05 4J027 AC02 AC03 AC04 AC06 AJ01 BA04 BA05 BA06 BA07 BA08 BA09 BA10 BA11 BA12 BA13 BA14 CB03 CB09 CC02 CD01 4J100 AB02Q AB04Q AB07R AB08Q AJ02R AJ08R AJ09R AL03Q AL04Q AL05Q AL08P BA08R15 AM04 AL08Q15P BA56R BB18Q BC04Q BC43P BC43Q CA01 CA04 CA05 DA61 JA32

Claims (3)

[Claims] 1. A thermosensitive light transmission control material comprising a polymer having a polyalkylene glycol group and water and / or a polar solvent other than water. 2. The thermosensitive light transmission controlling material according to claim 1, wherein the polymer further has a hydrophobic group. 3. The thermosensitive light transmission controlling material according to claim 2, wherein said polymer further has a hydroxyl group.