JPS6131721B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a visible light scattering polymer composite useful as optical filters, digital components, decorative items, etc., and a method for producing the same. More specifically, a polymer composite containing in a stable state a cholesteric liquid crystal with a helical pitch capable of selectively scattering light of wavelengths in the visible region, and a polymer composite produced by polymerizing a monomer containing the cholesteric liquid crystal. Regarding how to.

Until now, various attempts have been made to obtain polymers containing cholesteric liquid crystals that selectively scatter light of specific wavelengths according to the helical pitch, but the stability of cholesteric liquid crystals in polymers and their Problems such as the consistency of the helical pitch cannot be overcome, and there is still no known product that can be put to practical use.

The present inventor selectively scatters light of wavelengths belonging to the visible region, and as long as the base material is in a stable state without softening, In order to develop a material that retains cholesteric liquid crystals while the helical pitch remains virtually unchanged, we have conducted extensive research and found that by forming cholesteric liquid crystals in monomers and then polymerizing the monomers, we have succeeded in achieving this goal. The present invention was completed based on this finding.

That is, the present invention provides a cholesteric liquid crystal comprising at least one polypeptide selected from polyglutamic acid and its ester, which has a helical pitch structure capable of selectively scattering light of wavelengths in the visible region. The present invention provides a visible light scattering polymer composite characterized in that it is dispersed and fixed in a non-liquid crystal polymer while maintaining the following properties.

Such a visible light scattering complex is produced by dissolving a polypeptide selected from, for example, polyglutamic acid and its ester in a compound having at least one polymerizable unsaturated group. It can be easily obtained by forming a cholesteric liquid crystal having a helical pitch structure that can selectively scatter light, and then carrying out a polymerization reaction.

The substance capable of forming cholesteric liquid crystals used in this case includes polyglutamic acid or its ester, and these may be used alone or as a mixture of two or more. Examples of polyglutamic acid esters include polyglutamic acid methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester,
n-pentyl ester, n-hexyl ester, cyclohexyl ester, benzyl ester, p-
Mention esters of linear, branched or cyclic (including aromatic) alcohols having 1 to 10 carbon atoms and polyglutanic acid, such as chlorobenzyl ester, p-bromobenzyl ester or o-chlorobenzyl ester. I can do it. these are,
A homopolymer or copolymer of optical isomers as L-form or D-form, or a block copolymer or random copolymer having repeating units selected from the repeating units constituting the above-mentioned polyglutamic acid or its ester. It can be used in

In addition, examples of compounds having at least one polymerizable unsaturated group include N/N-dimethylacrylamide, N/N-dimethylmethacrylamide, acrylamide, methacrylamide, methacrylic acid or its ester, acrylic acid or its ester, and acetic acid. Vinyl, styrene, α-methylstyrene, p-chlorostyrene, p-bromostyrene,
Acrylonitrile, methacrylonitrile, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate Examples of methacrylic esters or acrylic esters include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, and n-butyl ester of these acids. Straight chain, branched or cyclic (including aromatic) alcohols having 1 to 16 carbon atoms, such as esters, cyclohexyl esters, benzyl esters, glycidyl esters, phenyl esters, hydroxyethyl esters or hydroxypropyl esters, and methacrylic There are esters with acids or acrylic acids.

These compounds dissolve polyglutamic acid or its ester to form cholesteric liquid crystals in solution and polymerize to give transparent to translucent polymers.

The visible light scattering polymer composite of the present invention can be obtained as follows.

That is, 0.1 to 1 part by weight of the cholesteric liquid crystal is added to 1 part by weight of a compound having at least one polymerizable unsaturated group.
Dissolve 4 parts by weight, preferably 0.4 to 1.5 parts by weight,
After forming cholesteric liquid crystals, the compound is polymerized. In this way, polyglutamic acid or its ester has the property of spontaneously forming cholesteric liquid crystals when dissolved in a compound having at least one polymerizable unsaturated group and the molecules can move easily. Therefore, if it is polymerized in a dissolved state, a fixed cholesteric liquid crystal can be obtained.

At this time, it is necessary to adjust the helical pitch of the cholesteric liquid crystal to one that selectively scatters light belonging to the visible region. This can be carried out as appropriate by changing the concentration or polymerization temperature of the compound.

When adjustment is made by changing the combination of the compound and the substance forming the cholesteric liquid crystal, the wavelength of light to be mainly scattered can be set by applying the following formula.

λ _p =n・p・cosθ (in the formula, λ _p is the wavelength of the mainly scattered light, n is the average refractive index of the composite of the present invention, p is the helical pitch of the cholesteric liquid crystal, and θ is the helical axis of the cholesteric liquid crystal. is the angle that forms the angle of incidence). For convenience, we use the refractive index of the polymer itself as the value of n, the value of θ as 0, that is, the value of cosθ as 1 (the value when light is incident from the direction of the helical axis of the cholesteric liquid crystal), and λ _p Even if the relationship between and p is selected, it is possible to obtain something relatively close to the desired one.

In addition, when adjusting the helical pitch of cholesteric liquid crystal by its concentration or polymerization temperature,
It is advantageous to investigate the relationship between helical pitch and concentration or polymerization temperature in advance.

In order to polymerize a compound having at least one polymerizable unsaturated group in the method of the present invention, it is necessary to contain cholesteric liquid crystals in a stable state in a spiral pitch that selectively scatters light of wavelengths in the visible region at temperatures below 80°C. A photopolymerization method in which the polymerization is carried out at a low temperature of , a radiation polymerization method or a method using a polymerization initiator are advantageous, and a photopolymerization method in which the polymerization is carried out at a temperature of 0 to 40°C is particularly preferred.

When producing the composite of the present invention, photosensitizers such as azobisisobutyronitrile and benzphenone may be added, if necessary.

In this way, the visible light scattering polymer composite of the present invention, which is manufactured into an appropriate form such as a film, block, rod, plate, or coated object, depending on its use, can be produced by softening the polymer that is the base material. It contains cholesteric liquid crystal in a stable state in which its helical pitch does not substantially change due to external factors such as temperature changes, electric fields, and magnetic fields below the temperature, and the polymer itself functions as a carrier for cholesteric liquid crystal. It does not require any other carrier to support it, and its surface is not sticky, so it is easy to handle.

The composite of the present invention selectively scatters light with wavelengths in the visible region, so it is beautifully colored red to purple under white light, so it is suitable for optical filters, digital materials, circularly polarizing filters for monochromatic light, and decorative uses. be.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 40 of poly-L-glutamic acid (molecular weight 48,000)
% by weight, azobisisobutyronitrile was added as a photosensitizer to N-N-dimethylacrylamide solution.
Add this material to a thickness of 0.1% by weight.
It was poured into the gap between two glass plates bonded together with a spacer of mm in diameter, and irradiated for 5 hours with an ultra-high pressure mercury lamp (SH6-160UV model manufactured by Tohosha Co., Ltd.) at a temperature of 0°C. Dimethylacrylamide was polymerized to obtain a film-like composite.

This material appeared blue when viewed from the direction perpendicular to the film surface, and remained the same color even at temperatures of 10 to 60°C. It was also found that this product is non-sticky and can be used as is as an optical filter or decorative item.

Example 2 A rod-shaped composite with a diameter of 10 mm was obtained in the same manner as in Example 1, except that the concentration of poly-L-glutamic acid was 30% by weight and a glass tube with an inner diameter of 10 mm was used as the reaction vessel. When this rod-shaped object was viewed under white light, it appeared to vary in color, from red to blue, depending on the angle.

Example 3 A mixed solution of 2.2 g of poly-L-glutamic acid propyl ester (molecular weight 70,000), 1.71 g of methyl methacrylate, and 0.09 g of ethylene glycol dimethacrylate was sufficiently stirred at room temperature to form a uniform liquid crystal solution, and then photointensification was performed. Benzophenone 10 as a sensitizer
mg, defoamed under reduced pressure, and about 0.2
2, which was bonded with g through a 0.15 mm thick spacer.
Three pieces of glass were poured into the voids of the glass plates, and each was irradiated at a constant temperature of 20°C, 30°C, or 40°C for 2 hours using the same ultra-high pressure mercury lamp as in Example 1. A thin film of about 0.15 mm was obtained.

Among the thin films obtained in this way, those polymerized at a temperature of 20°C are blue (center wavelength of selectively scattered light).
480nm) and green when polymerized at 30℃ (530nm).
m), those polymerized at 40°C appeared red (610 nm).

Example 4 Poly-L-glutamic acid propyl ester 2.32
A liquid crystal solution prepared from 1.43 g of methyl methacrylate, 0.17 g of butyl acrylate, and 0.08 g of ethylene glycol dimethacrylate was polymerized at a temperature of 20°C in the same manner as in Example 3. A thin film colored at a central wavelength of 540 nm was obtained.

Example 5 Poly-L-glutamic acid propyl ester 2.4
g, methyl methacrylate 1.52 g and styrene 0.08
The liquid crystal solution prepared in Example 4 was polymerized in the same manner as in Example 4, and the liquid crystal solution was polymerized in the same manner as in Example 4.
A colored thin film was obtained in m).

Example 6 A liquid crystal solution prepared in the same manner as in Example 3 from 8 g of poly-L-glutamic acid n-butyl ester (molecular weight 75,000), 8 g of triethylene glycol dimethacrylate, and 160 mg of azobisisobutyronitrile as a photosensitizer. Prepare three Pyrex test tubes with an inner diameter of 16 mm filled with approximately 5 g, and after thoroughly degassing them under reduced pressure, 20 g each.
Polymerization was carried out at 30°C or 40°C for 5 hours using the same ultra-high pressure mercury lamp as in Example 1. Of the three lumps obtained, those with a polymerization temperature of 20°C have a bluish-purple color, those with a polymerization temperature of 30°C have an overall bluish-green color, and depending on the direction, the blue and green parts are mixed. , the one at 40°C appeared yellow overall, with mottled red to green patterns mixed in depending on the direction.

Example 7 A part of the solution prepared in Example 6 was uniformly applied onto a black flat glass plate, and then photopolymerized at a temperature of 23° C. to obtain a thin film with a thickness of about 0.1 mm. This thing appeared to be colored bluish-purple.

Example 8 A liquid crystal solution prepared from 0.9 g of a copolymer of L-glutamic acid n-butyl ester and L-glutamic acid methyl ester in a molar ratio of 4:1 and 1.1 g of triethylene glycol dimethacrylate was defoamed under reduced pressure. The mixture was filled into a glass tube with an inner diameter of about 2 mm, and photopolymerized at a temperature of 30°C to obtain a blue-green round rod with a length of about 150 mm and a diameter of about 2 mm.

Claims (1)

[Scope of Claims] 1. A cholesteric liquid crystal comprising at least one polypeptide selected from polyglutamic acid and its ester and having a helical pitch structure capable of selectively scattering light of wavelengths in the visible region, A visible light scattering polymer composite characterized by being dispersed and fixed in a non-liquid crystal polymer while maintaining its structure. 2. A helical pitch structure in which a polypeptide selected from polyglutamic acid and its esters is dissolved in a compound having at least one polymerizable unsaturated group, and is capable of selectively scattering light of wavelengths in the visible region. 1. A method for producing a visible light scattering polymer composite, which comprises forming a cholesteric liquid crystal having the following properties and then carrying out a polymerization reaction.