JP2003055517A - Polymethyl methacrylate/titania hybrid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for incorporating titania in polymethyl methacrylate while retaining high transparency inherent in the polymethyl methacrylate. SOLUTION: The objective polymethyl methacrylate copolymer/titania hybrid, wherein the copolymer is a copolymer of methyl methacrylate and 3- methacryloyloxypropyl trimethoxysilane is provided. Thus, the objective hybrid including titania while retaining high transparency inherent in the polymethyl methacrylate and capable of cutting e.g. ultraviolet radiation falling in the <=320 nm region can be obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymethylmethacrylate copolymer-titania hybrid. The present invention also relates to the hybrid, wherein the polymethylmethacrylate copolymer is a copolymer of methylmethacrylate and 3-methacryloyloxypropyltrimethoxysilane. The invention further relates to a method for producing the hybrid film by a sol-gel method.

[0002]

2. Description of the Related Art Polymethyl methacrylate is widely used as an organic glass or the like because it has good transparency and excellent toughness. Further, titania is useful as an additive because it is hard and has an ultraviolet protection effect. Therefore,
In order to meet the demand for hardness and UV protection in organic glass and the like, it is possible to add titania to polymethylmethacrylate to impart hardness and UV protection, but it is generally said that it is light blocking. Due to the properties of titania, it is not easy to incorporate titania while maintaining the excellent transparency of polymethylmethacrylate. SiO ₂ is a (meth) acrylic polymer with excellent optical properties.
Inorganic / organic hybrid materials for lenses, which are uniformly dispersed in a three-dimensional microstructure and are transparent and have excellent optical characteristics, have been proposed, but the above-mentioned characteristics of titania are truly indispensable.

[0003]

An object of the present invention is to provide means for incorporating titania while maintaining the excellent transparency of polymethylmethacrylate.

[0004]

Means for Solving the Problems The present inventors have prepared a poly (methyl methacrylate) copolymer-titania hybrid film by a sol-gel method to retain the properties of both the poly (methyl methacrylate) copolymer and the titania. It was found that the film has excellent optical properties and physical properties. Polymethylmethacrylate homopolymer is not suitable for hybrid preparation, and therefore it is important to use polymethylmethacrylate copolymer. The polymethylmethacrylate copolymer-titania hybrid obtained by the present invention is excellent in both optical characteristics and physical properties, but it is noteworthy that it has both transparency and UV protection effect.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Polymethylmethacrylate, which has good transparency and excellent toughness, contains a composite of titania that is hard and has an ultraviolet protection effect while maintaining the excellent transparency of polymethylmethacrylate. The problem of the present invention of imparting hardness and UV protection effect to polymethylmethacrylate, as shown below, can be solved by preparing a polymethylmethacrylate copolymer-titania hybrid film by a sol-gel method. all right. In that case, a polymethylmethacrylate homopolymer is not suitable for hybrid preparation, and it is important to use a polymethylmethacrylate copolymer.

As the copolymerizable monomer, various monomers copolymerizable with methyl methacrylate (MMA) can be used, preferably a methacrylic monomer, more preferably a Si-containing methacrylic monomer, and most preferably 3-
Methacryloyloxypropyltrimethoxysilane (MS
i) are mentioned.

The molar ratio of methyl methacrylate (MMA) to the copolymerization monomer is preferably 98: 2 to 80:20, more preferably 95: 5 to 90:10.

As the titania, various compound forms can be used, but Ti (OPr) ₄ is particularly preferable. The amount of titania to be contained in combination is preferably 2 to 50% by weight based on Ti (OPr) _{4 with} respect to the polymethylmethacrylate copolymer, and more preferably with respect to the polymethylmethacrylate copolymer. (OPr) ₄ to 5 to 20% by weight.

The thickness of the transparent hybrid film is preferably 50 to 500 μm, more preferably 100 to 3
It is 00 μm.

Methyl methacrylate (MMA), a monomer
And 3-methacryloyloxypropyltrimethoxysilane (MSi), which is a copolymerization monomer, are mixed in benzene etc. with a molar ratio of 95: 5 and 90:10 etc., and heat-polymerized with benzoyl peroxide as an initiator. .

After completion of the reaction, the copolymer is poured into hexane or the like to recover the copolymer. The reaction product is confirmed by ¹ H-NMR measurement, CPC measurement and elemental analysis. After dissolving the obtained copolymer in tetrahydrofuran etc., titanium tetraisopropoxide Ti (OPr) ₄ as a titania component was mixed by changing the weight ratio with respect to the copolymer, and 1N hydrochloric acid was added as a catalyst and stirred. After that, it is spread on a petri dish or the like, left at room temperature for about 1 week, and then vacuum dried under heating to prepare a transparent hybrid film.

By UV-VIS (UV-VIS) spectrophotometry,
Those that do not contain titania transmit ultraviolet rays, whereas
It can be seen that mixing a small amount of titania can block ultraviolet rays in the region of 320 nm or less. The area expands further as the weight ratio of titania increases.

[0013]

EXAMPLES Examples of the present invention will be shown below.

EXAMPLE 1 Benzene was charged into benzene while changing the molar composition of the monomers methyl methacrylate (MMA) and 3-methacryloyloxypropyltrimethoxysilane (MSi), and benzoyl peroxide was used as an initiator at 4 ° C. at 4 ° C. Polymerized for hours. After the reaction,
It was poured into hexane and the copolymer was recovered. Confirmation of reactants
^{It was performed by 1} H-NMR measurement, CPC measurement, and elemental analysis. After dissolving the obtained copolymer in tetrahydrofuran, titanium tetraisopropoxide Ti (OPr) ₄ (manufactured by Nippon Soda Co., Ltd.)
Was mixed with the copolymer in a weight ratio of 9: 1 to 7: 3, 1N hydrochloric acid was added as a catalyst and stirred, and then spread on a Petri dish, and allowed to stand at room temperature for 1 week, then at 120 ° C for 3 weeks. After vacuum drying for a day, a transparent hybrid film was prepared. The thickness of the film was 200 μm. The composite content of titania did not impair the transparency of the poly (methyl methacrylate) copolymer even insignificantly.

It has been found that, while those which do not contain titania transmit ultraviolet rays, when a small amount of titania is mixed, ultraviolet rays in the region of 320 nm or less can be cut. The area expanded further as the weight ratio of titania increased.

Example 2 Benzyl peroxide was added as an initiator by charging benzene with a molar ratio of the monomers methyl methacrylate (MMA) and 3-methacryloyloxypropyltrimethoxysilane (MSi) being 95: 5 and 90:10. Was polymerized at 80 ° C. for 4 hours. After completion of the reaction, the mixture was poured into hexane to collect the copolymer. The reaction product was confirmed by ¹ H-NMR measurement, CPC measurement, and elemental analysis. After dissolving the obtained copolymer in tetrahydrofuran, titanium tetraisopropoxide Ti (OPr) ₄ (manufactured by Nippon Soda Co., Ltd.) was mixed by changing the weight ratio from 95: 5 to 80:20 with respect to the copolymer. Then, add 1N hydrochloric acid as a catalyst so that the molar ratio of Ti (OPr) ₄ and HCl is 1: 0.03, stir it, develop on a Petri dish, leave it at room temperature for 1 week, and vacuum it at 120 ° C for 3 days. A transparent hybrid film was prepared by drying. The thickness of the film was 200 μm. The composite content of titania did not impair the transparency of the poly (methyl methacrylate) copolymer even insignificantly.

By ultraviolet-visible (UV-VIS) spectrophotometry,
An ultraviolet-visible (UV-VIS) spectrum as shown in Fig. 1 was obtained. The horizontal axis represents wavelength (wave length, nm), and the vertical axis represents transmittance (Transmittance,%). As can be seen in FIG. 1, those that do not contain titania transmit ultraviolet light over a wide range even if the MSi composition changes, whereas titania is added to the polymethylmethacrylate copolymer based on Ti (OPr) ₄ standard.
When 5% by weight is mixed, ultraviolet rays in the region of 300 nm or less are cut, and when 20% by weight of titania is added to the polymethylmethacrylate copolymer based on Ti (OPr) ₄ , the ultraviolet rays in the region of 330 nm or less are cut. I understood.

[0018]

EFFECTS OF THE INVENTION According to the present invention, a polymethylmethacrylate / titania hybrid capable of blocking ultraviolet rays in the region of 320 nm or less can be obtained by compositely containing titania while maintaining excellent transparency of polymethylmethacrylate. To be As the weight ratio of titania increases, the range of ultraviolet rays that can be cut further increases.

[Brief description of drawings]

FIG. 1 is a diagram showing an ultraviolet-visible (UV-VIS) spectrum of a polymethylmethacrylate copolymer-titania hybrid film.

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Claims (3)

[Claims] 1. A polymethyl methacrylate copolymer-titania hybrid. 2. The hybrid according to claim 1, wherein the polymethylmethacrylate copolymer is a copolymer of methylmethacrylate and 3-methacryloyloxypropyltrimethoxysilane. 3. A method for producing the hybrid film according to claim 1 or 2 by a sol-gel method.