JPH0824625A - Microcapsules containing polyglutamic acid γ-ester and immobilization method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] Derived from polyglutamic acid γ-ester-containing microcapsules with no cohesiveness and excellent operability, and cholesteric liquid crystallinity with high designability by fixing the capsules in a polymer matrix. The present invention provides a method for easily and reproducibly immobilizing a polyglutamic acid γ-ester exhibiting an extremely characteristic color. [Structure] A core film is a copolymer of glutamic acid γ-benzyl ester having thermotropic cholesteric liquid crystallinity and glutamic acid γ-alkyl ester, and an epoxy resin and a hydrophilic amine having two or more amino groups in the molecule are used as a wall film. A microcapsule containing polyglutamic acid γ-ester contained as a constituent of

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention provides a polyglutamic acid γ-ester containing micro-color which exhibits a very characteristic color derived from cholesteric liquid crystallinity and is useful as a highly-designable colorant used for marking films and decorative panels. The present invention relates to a capsule and a method of immobilizing the capsule.

[0002]

2. Description of the Related Art Many organic compounds forming a liquid crystal structure are known. Liquid crystals are roughly classified into thermotropic liquid crystals that form a liquid crystal state by applying heat and lyotropic liquid crystals that form a liquid crystal state under the presence of a solvent. In addition, cholesteric (chiral nematic) liquid crystals and chiral smectic liquid crystals are characteristic liquid crystals produced by optically active molecules such as polypeptides. The glutamic acid γ-ester polymer is one of polymer liquid crystals known as cholesteric liquid crystal due to the molecular alignment state, and exhibits both lyotropic liquid crystal property and thermotropic liquid crystal property depending on the type of ester side chain. That is, a glutamic acid γ-ester polymer forms an α-helix in various organic solvents and retains a rigid rod-shaped molecule essential for a lyotropic liquid crystal.
By introducing a flexible alkyl group having a function as a solvent into the ester side chain of the ester polymer, it is possible to have a thermotropic liquid crystallinity showing a thermal phase transition from crystal to liquid crystal. [Macromolecu
les, 17, 1004 (1984), Macromolecules, 18, 2141 (198
5), Polym. Prep. Jpn., 30 , 283 (1980)]. Such a property of the liquid crystal is called a thermotropic cholesteric liquid crystal property.

The liquid crystal composed of the above-mentioned glutamic acid .gamma.-ester polymer exhibits a selective reflectivity for circularly polarized light in a narrow wavelength region and a very large optical rotatory power. The wavelength of the circularly polarized light that is selectively reflected is proportional to the cholesteric pitch length, and exhibits a color tone similar to a red to blue fluorescent color at a visible light wavelength (functional material, Watanabe Sequential, September 1987 issue, 20). page).
This color tone is the glittering brilliance itself of naturally occurring beetle wings, which is the selective reflection of light originating from the extremely characteristic cholesteric structure.

General formula (I)

[0005]

Embedded image

(In the formula, R represents alkyl having 10 to 30 carbon atoms, m and n represent positive integers, and the degree of polymerization (m +
n) is 50 ≦ m + n ≦ 2000, m / n is 80/20 to
10/90, and the benzyl ester unit and the alkyl ester unit are both L-form or both D-form), and the copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester is 1
It is a thermotropic liquid crystalline polypeptide which undergoes a phase transition to liquid crystal at 00 to 180 ° C. and stably retains its α-helix structure, and its immobilization is disclosed (Japanese Patent Publication No. 4-30969). . However, the glutamic acid γ-ester copolymer used here has high aggregability and poor operability. Further, when fixing this copolymer, the liquid crystal orientation is formed by once making it in a molten state and then spreading it thinly and applying shear stress.
In this case, the shear stress applied to the thinly spread glutamic acid γ-ester copolymer thin film is made uniform,
Since the temperature applied to the thin film also needs to be uniform, a high level of technology is required for immobilization.

[0007]

An object of the present invention is to provide a polyglutamic acid γ-ester-containing microcapsule which is excellent in operability without agglomeration and which is fixed in a polymer matrix. Accordingly, it is an object of the present invention to provide a method for easily and reproducibly immobilizing a polyglutamic acid γ-ester having a very characteristic color derived from a cholesteric liquid crystallinity having a high design property.

[0008]

The present invention provides a core substance of a copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester having thermotropic cholesteric liquid crystallinity (hereinafter, also referred to as polyglutamic acid γ-ester). And a polyglutamic acid γ-ester-containing microcapsule containing an epoxy resin and a hydrophilic amine having two or more amino groups in the molecule as a constituent of a wall film, and the polyglutamic acid γ-ester-containing microcapsule in a polymer matrix. It relates to a method for immobilizing polyglutamic acid γ-ester having thermotropic cholesteric liquid crystallinity, which is characterized in that

As a copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester,
Any polymer having thermotropic cholesteric liquid crystallinity may be used, and the copolymer represented by the general formula (I) is preferably used. As the alkyl, linear or branched alkyl having 10 to 30 carbon atoms, for example, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,
Nonadecyl, Aicosil, Henicosil, Docosyl,
Examples thereof include tricosyl, tetracosyl, pentacosyl, triacontyl and the like. Among them, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, aicosyl, docosyl and tetracosyl having 12 to 24 carbon atoms are preferable.

The benzyl group / alkyl group ratio (m / n) in the copolymer of the present invention is not particularly limited, but is preferably 80/20 to 10/90, more preferably 70. / 30 to 40/60. Within this range, repeating units having a benzyl group and repeating units having an alkyl group are usually present randomly. The degree of polymerization (m + n) of the copolymer of the present invention is also not particularly limited, but it is preferably 50 to 2000, and more preferably 100 to 1500.

Any epoxy resin may be used as long as it can form a wall film with a hydrophilic amine, and an amphipathic epoxy resin is preferable. The amphipathic epoxy resin may be any amphipathic epoxy resin having two or more epoxy groups or glycidyl groups in the molecule and which is usually used, ((molecular weight of epoxy resin / epoxy group) Value of 180 to 20000, for example, bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, novolac type epoxy resin, halogenated bisphenol. A type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, alicyclic epoxy resin,
At least one selected from urethane-modified bisphenol A type epoxy resins can be mentioned.

The hydrophilic amine may be any one having two or more amino groups in the molecule and capable of forming a wall film together with the epoxy resin, but the value of (molecular weight of amine / number of hydrogen on amino group) Is preferably 300 or less, and when it is larger than this range, cohesion resistance, heat resistance and solvent resistance are not imparted, and the effect as a capsule is not observed. For example, ethylenediamine, propylenediamine, 1,2
-Diaminopropane, butylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, phenylenediamine, diethylenetriamine, triethylenetetramine, dipropylenetriamine, methyliminobis (propylamine), bis (3-
Aminopropyl) ether, 1,2-bis (3-aminopropoxy) ethane, 1,3-bis (3-aminopropoxy) -2,2-dimethylpropane, α, ω-bis (3
-Aminopropyl) polyethylene glycol ether.

The polymer matrix may be any resin as long as it is colorless and transparent, does not impair the optical properties of the particles, and has a decomposition temperature of 200 ° C. or higher and can fix the polyglutamic acid γ-ester-containing microcapsules. For example, but not limited to, carboxylic acid group, sulfonic acid group, phosphoric acid group, hydroxyl group, oxirane group, active methylol group, amino group, epoxy group, reactive carbon-carbon unsaturated bond, isocyanate group, block Isocyanate group, having a functional group such as halogen, a polyvalent isocyanate compound, an epoxy resin, a polyvalent amine compound, a polyvalent hydroxy compound, a carboxylic acid compound, a carboxylic anhydride, an acrylic resin, composed of at least one selected from melamine resin Examples of the resin include

Examples of the polyvalent isocyanate compound include aliphatic polyisocyanates such as hexamethylene diisocyanate, hexamethylene diisocyanurate, lysine diisocyanate, trimethylhexamethylene diisocyanate and lysine triisocyanate, isophorone diisocyanate, isophorone diisocyanurate,
Hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, hydrogenated tolylene diisocyanate, alicyclic polyisocyanate such as hydrogenated xylylene diisocyanate, tolylene diisocyanate, phenylene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, aromatic isocyanate such as naphthalene diisocyanate, etc. can give. Among them, non-yellowing type ones such as aliphatic polyisocyanate and alicyclic polyisocyanate are preferable in order to maintain a very characteristic color tone derived from cholesteric liquid crystal property for a long time.

Examples of the epoxy resin and the polyvalent amine compound include the above-mentioned epoxy resin and hydrophilic amine. Examples of the polyhydric hydroxy compound include ethylene glycol, butanediol, hexanediol, polyethylene glycol, polyether polyol, polyester polyol, polycaprolactone polyol, polycarbonate polyol, bisphenol derivative, polybutadiene diol, polyacrylic polyol and the like.

Examples of the carboxylic acid compound and carboxylic acid anhydride include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-biphenylcarboxylic acid, succinic acid and adipine. Acids, azelaic acid, sebacic acid, dodecanedioic acid, aliphatic dicarboxylic acids such as dimer acid, 1,3-
Cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,4-cyclohexylenedicarboxylic acid, polycarboxylic acid such as trimellitic acid and pyromellitic acid, succinic anhydride, phthalic anhydride, etc. Carboxylic acid anhydrides and the like.

Examples of the acrylic resin include aromatic vinyl compounds such as styrene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, fumaric acid and itaconic acid, their neutralized products or esters, and glycidyl methacrylate. Unsaturated carboxylic acid esters of alcohols containing functional groups such as 2-hydroxyethyl methacrylate and 2-hydroxypropyl acrylate, vinyl carboxylic acid esters such as vinyl acetate, vinylamide compounds such as acrylamide and methacrylamide, and aliphatic compounds such as butadiene. Olefin compounds such as diene, ethylene, propylene and isobutylene, halogen-substituted vinyl compounds such as vinyl chloride and vinylidene chloride,
Examples thereof include homo- and copolymer resins obtained by polymerizing one or more selected from monomers such as di- and trivinyl compounds such as divinylbenzene, 1,4-butanediol diacrylate, and trimethylolpropane triacrylate. .

Examples of the melamine resin include various melamine resins such as methylated melamine resin, butylated melamine resin and melamine-urea co-condensed resin. These resins can be used alone or in combination of two or more. Further, an aqueous emulsion of these resins, or a mixture of two or more aqueous emulsions can also be used.

The copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester can be obtained by the method described in Japanese Patent Publication No. 4-30969. Further, in order to use the above-mentioned copolymer (polyglutamic acid γ-ester) as a core substance of microcapsules, it is preferable to use it in the form of fine particles.
Fine particles of ester can be obtained, for example, by dispersing polyvinyl alcohol or the like as an emulsifier [Polym. J., vol 17, 13
01 (1985)]. The particle size of the polyglutamic acid γ-ester fine particles used in the present invention is 0.1 to
The thickness is 1000 μm, preferably 5 to 200 μm. When the particle size is smaller than this range, α-helix is difficult to be formed, and when it is larger than this range, the coating with the wall film becomes difficult, which is not preferable.

The wall film in the microcapsule containing polyglutamic acid γ-ester can be obtained by interfacially polymerizing an epoxy resin and a hydrophilic amine. Microcapsules containing polyglutamic acid γ-ester,
An organic solution of polyglutamic acid γ-ester and epoxy resin can be obtained, for example, by emulsifying in an aqueous solution containing polyvinyl alcohol as an emulsifier, removing the organic solvent, and adding a hydrophilic amine to the resulting solution for polymerization. .

When an amphipathic epoxy resin is used as the epoxy resin, the amphipathic epoxy resin is preferably used in a proportion of 1 to 100 parts by weight based on 100 parts by weight of the polyglutamic acid γ-ester. When the content of the epoxy resin is less than this range, the obtained fine particles are not provided with cohesion resistance, heat resistance and solvent resistance, and the effect as a capsule cannot be obtained. On the other hand, when it is larger than this range, the content of polyglutamic acid γ-ester in one particle is lowered, and a satisfactory liquid crystal effect cannot be seen, which is not preferable.

As the organic solvent, a hydrophobic solvent having no active hydrogen is preferable, for example, dichloromethane,
1,2-dichloroethane, chloroform, halogen solvents such as carbon tetrachloride, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as acetone, ether solvents such as diethyl ether, benzene, toluene,
Examples thereof include aromatic hydrocarbon solvents such as xylene, ester solvents such as ethyl acetate and butyl acetate, and mixed solvents thereof may be used.

The hydrophilic amine is added in an amount of 0.1 to 2000 equivalents per 1 equivalent of the epoxy group. The polymerization reaction is 30 ~
It is performed in the temperature range of 100 ° C. When a glycidyl ester type epoxy resin is used as the epoxy resin, the capsules produced may have cohesive properties and may not have solvent resistance. However, after dispersing this capsule in a solvent that does not dissolve polyglutamic acid such as an aliphatic solvent, for example, by adding a monomer or prepolymer of a polyvalent isocyanate compound that reacts with an amino group or a hydroxyl group present in the wall film, , Physical properties can be improved. In this case, 10 parts by weight or more of solvent is used for 1 part by weight of the capsule. If the amount of the solvent is smaller than this range, the particles adhere to each other, which is not preferable.

As the prepolymer, for example, a polyvalent isocyanate compound is reacted with a compound having active hydrogen, for example, ethylene glycol to give an isocyanate group-terminated prepolymer. Monomers or prepolymers of polyvalent isocyanate compounds,
It is added in the range of 0.01 to 10 equivalents with respect to the reactive group (amino group or hydroxyl group) existing in the wall film. When the amount of polyvalent isocyanate compound is smaller than this range,
Does not meet the amount of cross-linking agent equivalent to improve the wall membrane surface,
On the other hand, if it is larger than this range, it may react with polyglutamic acid to inhibit liquid crystallinity, which is not preferable.

The reaction is carried out in the temperature range of 20 to 60 ° C,
Further, a catalyst such as dibutyltin laurate or dibutyltin maleate may be added. The size of the particles prepared depends on the cholesteric phase-forming ability of the polyglutamic acid γ-ester used, but is not particularly limited as long as it is not less than the particle size exhibiting cholesteric liquid crystallinity. For example, when it is used for a marking film or a panel for decoration, it is preferably adjusted to have a particle size of 0.1 to 1000 μm, more preferably 5 to 200 μm. The particle size can be adjusted by changing the polyvinyl alcohol aqueous solution concentration, the polyglutamic acid solution concentration, the stirring speed, and the like.

Next, a method for immobilizing polyglutamic acid γ-ester having thermotropic cholesteric liquid crystal property will be described. Immobilization of polyglutamic acid γ-ester is carried out by dispersing the polyglutamic acid γ-ester-containing microcapsules obtained by the above-mentioned production method in a solution containing a binder constituting the polymer matrix or a component thereof to form a crosslinked film (polymer matrix). Is formed by forming. For example, in the case of coating film preparation, polyglutamic acid γ-ester-containing microcapsules are dispersed in a solution containing a binder or its constituents to form a coating film, and then the film is dried and further baked to give polyglutamic acid γ. -The ester can be immobilized.

As the binder or its constituents,
Examples thereof include, but are not limited to, polyvalent isocyanate compounds, epoxy resins, polyvalent amine compounds, polyvalent hydroxy compounds, carboxylic acid compounds, carboxylic acid anhydrides, acrylic resins and melamine resins. Examples of the polyvalent isocyanate compound, the epoxy resin, the polyvalent amine compound, the polyvalent hydroxy compound, the carboxylic acid compound, the carboxylic acid anhydride, the acrylic resin, and the melamine resin can include those mentioned above.

The embodiments of the present invention will be specifically described below with reference to examples.

[0029]

【Example】

[Example 1] 1 g of a copolymer of γ-benzyl glutamate and γ-dodecyl glutamate (synthesized by the method described in Japanese Patent Publication No. 4-30969, dodecyl group content 38%, degree of polymerization 140) and bisphenol A type epoxy 1, containing 0.1 g of resin (Toto Kasei Co., Ltd .: YD-011)
After 40 g of the 2-dichloroethane solution was emulsified in 250 g of a 2% by weight aqueous solution of polyvinyl alcohol (Kanto Chemical Co., Inc., saponification degree: 86.589 mol%), 1,2-dichloroethane was removed by slightly flowing nitrogen. 0.7 g of hexamethylenediamine was added to this dispersion solution, and the mixture was stirred at 60 ° C. for 3 hours. After filtering the obtained encapsulated particles, washed with water,
It was dried at 60 ° C. The particle diameter of this particle is 20 to 40 μm.
Therefore, there was no cohesive property (FIG. 2), and it did not melt even when heated to 150 ° C. or higher.

Example 2 Bisphenol F type epoxy resin (Toto Kasei Co., Ltd .: YDF-1) as the epoxy resin
75) The same as Example 1 except that 0.1 g was used and 0.3 g of 1,3-bis (3-aminopropoxy) -2,2-dimethylpropane (Koei Chemical Industry Co., Ltd.) was used as the amine compound. Encapsulated particles were prepared by the operation, and particles having the same physical properties as the particles obtained in Example 1 were obtained.

[Embodiment 3] A novolac type epoxy resin (Toto Kasei Co., Ltd .: YDCN-70) was used as the epoxy resin.
1) Encapsulated particles were prepared in the same manner as in Example 1 except that 0.1 g was used and 1.4 g of hexamethylenediamine was used as the amine compound, and they had the same physical properties as the particles obtained in Example 1. The particles were obtained.

Example 4 A glycidyl ester type epoxy resin (Toto Kasei Co., Ltd .: PG-2 as an epoxy resin
07S) 0.3 g was used, and encapsulated particles were prepared by the same operation as in Example 1 except that 12 g of ethylenediamine was used as the amine compound. 0.3 g of the obtained particles
Was dispersed in 80 ml of n-hexane, 0.02 g of hexamethylene diisocyanate and 0.005 g of dibutyltin laurate were added, and the mixture was shaken at room temperature for 18 hours to obtain particles having the same physical properties as the particles obtained in Example 1. It was

Example 5 Acrylic emulsion resin (Kyowa Hakko Kogyo Co., Ltd.) was added to 1 g of the encapsulated particles prepared in Example 1.
Ltd .: YS-258V, solid content 42%) and melamine resin (Sumitomo Chemical Co., Ltd .: Smith M-50W, solid content 80)
%) In a weight ratio of 8 to 2 and the coating film is adjusted (dried at 60 ° C. for 30 minutes and baked at 150 ° C. for 15 minutes) to disperse the encapsulated particles in the polymer matrix. A coating film was prepared. The coating is 1
When heated to 40 ° C, the blue color corresponding to the wavelength region 430 to 480 nm is emitted. When heated to 155 ° C, the wavelength region 50 is increased.
It exhibited a green color corresponding to 0 to 560 nm and could change the color any number of times by changing the temperature.

[Example 6] 6 g of a mixed solution of cellosolve acetate and methyl ethyl ketone in a weight ratio of 9: 1 was added to 2 g of the encapsulated particles prepared in Example 4, polyacrylic polyol (Dainippon Ink and Chemicals, Inc .: Acridic)
A-801-P, solid content 49.8% 2 g and lysine triisocyanate 0.9 g were added to prepare a coating film (60 ° C.).
After drying for 30 minutes at 140 ° C. and baking for 1.5 hours), a coating film in which the encapsulated particles were dispersed in the polymer matrix was prepared.

[0035]

EFFECTS OF THE INVENTION According to the present invention, microcapsules containing polyglutamic acid γ-ester excellent in cohesiveness and excellent in operability, and cholesteric liquid crystallinity having high designability by fixing the capsules in a polymer matrix are obtained. There is provided a method for easily and reproducibly immobilizing polyglutamic acid γ-ester exhibiting a very characteristic color.

[Brief description of drawings]

FIG. 1 γ-benzyl glutamate and γ-glutamate
It is a micrograph when a copolymer with dodecyl (dodecyl group content 38%, degree of polymerization 140) is made into fine particles.

FIG. 2 is a micrograph of microcapsules containing polyglutamic acid γ-ester prepared in Example 1.

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Claims (4)

[Claims] 1. A copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester having a thermotropic cholesteric liquid crystallinity (hereinafter, also referred to as polyglutamic acid γ-ester) is used as a core substance, and an epoxy resin and a molecule thereof are used. A polyglutamic acid γ-ester-containing microcapsule containing a hydrophilic amine having two or more amino groups as a constituent of a wall film. 2. A copolymer of glutamic acid γ-benzyl ester and glutamic acid γ-alkyl ester is represented by the general formula (I): (In the formula, R represents alkyl having 10 to 30 carbon atoms, m and n represent positive integers, and the degree of polymerization (m + n) is 50 ≦ m.
+ N ≦ 2000, m / n is 80/20 to 10/90, and the benzyl ester unit and the alkyl ester unit are both L-forms or both D-forms), which is a polyglutamic acid γ-ester. A microcapsule containing the polyglutamic acid γ-ester according to claim 1. 3. A method of immobilizing polyglutamic acid γ-ester having thermotropic cholesteric liquid crystallinity, which comprises immobilizing the polyglutamic acid γ-ester-containing microcapsules according to claim 1 in a polymer matrix. 4. The polymer matrix has a decomposition temperature of 200.
The method for immobilizing poly-glutamic acid γ-ester according to claim 3, comprising a polymer having a temperature of ℃ or higher.