JP2003147148A - Polymethyl methacrylate/zirconia hybrid film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polymethyl methacrylate/zirconia hybrid keeping the excellent transparency of a polymethyl methacrylate. SOLUTION: The hybrid film of a methyl methacrylate copolymer and zirconia is provided.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polymethylmethacrylate copolymer-zirconia hybrid film. The invention also relates to said hybrid film, 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, zirconia is hard and brittle, but has a high refractive index and thus has an ultraviolet protection effect, and is therefore useful as an additive. Therefore, in order to meet the demand for hardness and UV protection in organic glass and the like, it is possible to add zirconia to polymethylmethacrylate to provide hardness and UV protection, but the refractive indices of the two differ greatly. Therefore, it is not easy to incorporate zirconia while maintaining the excellent transparency of polymethylmethacrylate. Inorganic / organic hybrid materials for lenses, which are transparent and have excellent optical properties, in which a (meth) acrylic polymer having excellent optical properties is uniformly dispersed in a SiO ₂ -based three-dimensional microstructure have been proposed. Zirconia Some of the above characteristics of are truly irreplaceable.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a means for incorporating zirconia while maintaining the excellent transparency of polymethylmethacrylate so as to exhibit the characteristics of zirconia.

[0004]

The present inventor can maintain the properties of both a poly (methyl methacrylate) copolymer and zirconia by preparing a poly (methyl methacrylate) copolymer-zirconia hybrid film by a sol-gel method, It has been found that the optical properties and physical properties of the film are extremely excellent. Polymethylmethacrylate homopolymer is not suitable for hybrid film preparation, and it is therefore important to use polymethylmethacrylate copolymer. The polymethylmethacrylate copolymer-zirconia hybrid film obtained by the present invention is excellent in both optical properties 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, is mixed with zirconia which is hard and has an ultraviolet protection effect while maintaining the excellent transparency of polymethylmethacrylate. It was found that the problem of the present invention of imparting hardness and UV protection effect to polymethylmethacrylate can be solved by preparing a polymethylmethacrylate copolymer-zirconia hybrid film by the sol-gel method as shown below. . In that case, a polymethylmethacrylate homopolymer is not suitable for hybrid film 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 99: 1 to 80:20, more preferably 95: 5 to 90:10.

As the zirconia, various compound forms can be used, but zirconium tetra-n-butoxide Zr (OBu) ₄ is particularly preferable. The amount of zirconia contained in the composite is preferably 2 to 50% by weight based on Zr (OBu) _{4 with} respect to the polymethylmethacrylate copolymer, and more preferably with respect to the polymethylmethacrylate copolymer.
It is 5 to 20% by weight based on Zr (OBu) ₄ .

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 was confirmed by ¹ H / NMR measurement and CPC measurement,
Perform by elemental analysis. After dissolving the obtained copolymer in tetrahydrofuran or the like, zirconium tetra-n-butoxide Zr (OBu) ₄ as a zirconia component was mixed in the copolymer at different weight ratios, 1N hydrochloric acid was added as a catalyst, and the mixture was stirred. The mixture is spread on a petri dish and 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,
It can be seen that, while those which do not contain zirconia transmit ultraviolet rays, when a small amount of zirconia is mixed, ultraviolet rays in the region of 250 nm or less can be cut. The region further expands as the weight ratio of zirconia increases.

[0013]

EXAMPLES Examples of the present invention will be shown below.

The molar ratio of methyl methacrylate (MMA) and 3-methacryloyloxypropyltrimethoxysilane (MSi), which are the synthetic monomers of the copolymer, was 90:10. MMA and MSi were charged in benzene and polymerized at 80 ° C. for 4 hours using benzoyl peroxide as an initiator. After completion of the reaction, the copolymer (MMA / MSi) was recovered by introducing it into n-hexane as a precipitant. Confirm reaction product ¹
It was performed by 1 H-NMR measurement, GPC measurement, and elemental analysis.

Preparation of Hybrid 3 g of the obtained copolymer was dissolved in 1.2 mol of tetrahydrofuran (THF), and 1 mol of zirconium tetra-n-butoxide Zr (OBu) ₄ (Nippon Soda) was dissolved in 14.8 mol of THF. The above solution is added and stirred (solution A). Separately, prepare a solution in which 1N-HCl as a catalyst is dissolved in 7.4 mol of THF,
At this time, the molar ratio of Zr (OBu) ₄ : HCl was set to 1: 0.03 (solution B). Since highly reactive Zr (OBu) ₄ was precipitated by direct addition of water, the water required for hydrolysis was supplied from 1N-HCl. The solution B was added to the solution A, and the solution was vigorously stirred for several minutes, then developed on a silane coupling-treated petri dish, and allowed to stand at room temperature for 1 week for gelation. The obtained transparent film was heat treated in vacuum at 120 ° C. for 3 days to prepare a sample. The thickness of the film was 200 μm. Copolymer (MMA / MSi ＝
The combined amount of Zr (OBu) ₄ relative to 90:10) is 0, 10, 20, 30% by weight. The amount of zirconia obtained from thermogravimetric measurement was almost the same as the calculated value from the charged amount.

Physical Properties Measurement DVA-220 manufactured by IT Measurement Co., Ltd. was used for dynamic viscoelasticity measurement at 10 Hz and a heating rate of 5 ° C./min. UV / Visible (UV
・ VIS) UV-2500PC manufactured by Shimadzu Corporation for spectrophotometric measurement
For the refractive index measurement, an Abbe refractometer 3T (sodium D line: wavelength 589 nm) manufactured by Atago Co. was used.

Test Results UV / VIS Measurement From the UV / VIS measurement, the hybrid films in which the copolymer and Zr (OBu) ₄ were composited cut ultraviolet rays of about 250 nm or less, but show high transmission in other visible light regions. Showed the rate. The refractive index increased linearly with the increase of the composite amount of Zr (OBu) ₄ .

Dynamic viscoelasticity measurement The results of dynamic viscoelasticity measurement are shown in FIG. In Figure 1, the vertical
The axis shows the storage elastic modulus (Pa) and the loss tangent tan δ, and the horizontal axis shows
Indicates temperature (° C). For comparison, PMMA film (MMA / MSi
/ Zr (OBu)_Four= 100/0/0) are also shown. PMMA segment
Loss tangent tan near 100 ℃ based on the micro Brownian motion of
The δ peak shows that when the MSi composition of the copolymer is 10 mol%,
Shifted to a high temperature side of about 50 ° C and the rubber-like plastic has a storage elastic modulus E '.
The toe area appears. This is the silanol group of the MSi side chain
This silica bond forms a network structure due to the chemical bond between them.
Is to bind the PMMA segment. MSi composition
By default, Zr (OBu)_Four, The tan δ peak becomes lower,
It broadens and shifts to the high temperature side,
The E'value increased and the heat resistance increased. This is Zr (OBu) _Four
When combined with Zr (OBu), which has high reactivity_FourIs hydrolyzed, severely reduced
After combining, the zirconia end and the silanol group of the MSi side chain
React to form an inorganic domain, which is a complex
Chain length of PMMA grows larger with increasing amount
Is constant, so to strongly suppress segmental motion
it is conceivable that.

[0019]

EFFECTS OF THE INVENTION According to the present invention, a polymethylmethacrylate / zirconia hybrid film can be obtained in which zirconia is compositely contained while maintaining excellent transparency of polymethylmethacrylate, and the characteristics of zirconia are exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing the results of dynamic viscoelasticity measurement of a polymethylmethacrylate copolymer-zirconia hybrid film.

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Claims (3)

[Claims] 1. A polymethylmethacrylate copolymer-zirconia hybrid film. 2. The hybrid film of 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.