JP2001011122A - Transparent resin material for optical use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical transparent resin material which has excellent optical characteristics, low water absorption, high heat resistance and good adhesivity, by including as a main component a polymer obtained by polymerizing a vinylic monomer, if necessary, with one or more other monomers. SOLUTION: This optical transparent resin material contains a polymer as a main component, preferably in an amount of 50 to 100 wt.%, more preferably 70 to 100 wt.%. The polymer is obtained by polymerizing (A) a vinylic monomer of the formula [R1 is H or methyl; Z is a (substituted) organic cyclic hydrocarbon group-containing 7 to 23C divalent hydrocarbon; R2 is H, a (substituted) 1 to 12C alkyl, a (substituted) 6 to 13C alicyclic hydrocarbon, a (substituted) 6 to 14C aromatic hydrocarbon] in an amount of preferably 100 to 5 wt.%, more preferably 100 to 30 wt.%, if necessary, with (B) one or more other monomers capable of being copolymerized with the component A preferably in an amount of 0 to 95 wt.%. The component A preferably has a weight- average mol.wt. of 1,000 to 1,000,000 (determined by a light-scattering method, or the like, in a good solvent such as tetrahydrofuran).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optical transparent resin material which is suitable for optical elements such as optical lenses, optical fibers, optical disks and the like, and which can be formed by molding.

[0002]

2. Description of the Related Art The most general-purpose material for optical elements is, of course, inorganic glass. However, as a new material for an optical element, a transparent resin material has been widely used because it is particularly excellent in lightness and moldability. Polycarbonate resins, polystyrene resins, and polymethyl methacrylate resins have already been industrialized as optical transparent resin materials, but polymethyl methacrylate resins have high transparency and typical isotropic properties with a small birefringence. Because it has, it is particularly suitable for optical transparent resin materials,
It is called organic glass.

However, since polymethyl methacrylate resin has high water absorption, development of a novel polymethyl methacrylate resin having low water absorption is urgently required. As a typical example, a copolymer of a hydrophobic copolymerizable compound such as an alicyclic methacrylate and methyl methacrylate has been reported. For example, JP-A-58-125742 discloses a polycyclohexyl methacrylate resin, and JP-A-61-73705 discloses a tricyclodecyl (meth) acrylate resin.

[0004]

However, recently,
Optical transparent resin materials have been used for advanced optical elements such as optical lenses, optical fibers, optical disks for information recording media using laser light, and optical waveguide circuits. It's getting tougher. In particular, the optical transparent resin materials developed so far have the following problems.

The first problem is that, for example, the water absorption of an optical transparent resin material such as polymethyl methacrylate resin is still high, and does not satisfy the required performance when used for advanced optical elements. Generally, optical transparent resin materials with high water absorption absorb environmental moisture,
Problems such as a change in dimensions and warpage of a molded product, a change in surface accuracy due to a change in environmental conditions, and a change in the refractive index occur, and the stability as an optical element is lacking. Further, when the material is used for an information recording medium such as an optical disk, the recording film is deteriorated due to moisture absorption, and an error occurs during reproduction.

A second problem is that a transparent resin material for optical materials such as polycyclohexyl methacrylate resin has a low glass transition point, and thus has a problem of poor heat resistance.
For example, in the case of an optical lens, an optical lens made of a transparent resin material for optics has come to be used for a higher-energy optical system.
It is required to have heat resistance that does not cause deformation or deterioration. In addition, optical elements are generally becoming smaller and thinner, and accordingly, heat resistance is required.

A third problem is that optically transparent resin materials such as tricyclodecyl (meth) acrylate resin are excellent in low water absorption and heat resistance, but are inferior in adhesiveness. . When the material is used for an optical disk made of a single plate, Al is vapor-deposited on one surface of an optical transparent resin material constituting a substrate. The Al film formed on the surface of the disk is provided to reflect laser light, and has a mechanism of reading recorded information from the intensity of the reflected light. Therefore, the Al film is required to form a smooth surface state and maintain that state for a long period of time. For this purpose, a transparent resin material for optics and Al
Good and stable adhesiveness between them is required, and adhesion to Al is emphasized as a basic performance of the optical transparent resin material.

Further, other general-purpose resin materials such as polystyrene resin and polycarbonate resin have large wavelength dependence (dispersion) and birefringence of the refractive index because the material itself has anisotropy. When the material is used for an information recording medium such as an optical disk, there is a problem that a reading error by a laser beam increases.

The present invention has been made in view of the above circumstances, and based on a polymethyl methacrylate resin, utilizing the low dispersion and low birefringence due to its high isotropy,
An object of the present invention is to provide a transparent optical resin material having excellent optical properties, low water absorption, high heat resistance, and good adhesiveness.

[0010]

According to the present invention for solving the above-mentioned problems, the vinyl monomer represented by the general formula (1) can be copolymerized alone or with the vinyl monomer. There is provided an optically transparent resin material containing, as a main component, a polymer obtained by polymerization with another monomer.

[0011]

Embedded image (Wherein, R ¹ is a hydrogen atom or a methyl group, Z is a substituted or unsubstituted bridged cyclic hydrocarbon group having 7 to 23 carbon atoms.
R ² is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 6 to 13 carbon atoms, or a substituted or unsubstituted Represents a substituted aromatic group having 6 to 14 carbon atoms. )

[0012]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, specific examples of Z in the general formula (1), tricyclo [5.2.1.0 ^{2, 6]} decyl methylene group, a tricyclo [5.2.1.0 ^{2, 6]} decanediyl group, methyl Tricyclo [5.2.1.0 ^2,6 ] decanediyl group,
Adamantane-diyl group, a norbornanediyl group, methyl norbornane-diyl group, iso norbornane-diyl group, tetracyclo [4.4.0.1 ^2,5 .1 ^7,10] dodecanediyl group, methyl tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10} ] dodecanediyl group,
Hexacyclo ^{[6.6.1.1 3,6 .1 10,13 .0 2,7 .0} 9,14] heptadecane-diyl group, methylhexahydrophthalic cyclo [6.6.1.1 ^{3, 6} .1
^10,13 .0 ^2,7 .0 ^9,14] heptadecane-diyl group, octacyclo ^{[8.8.0.1 2,9 .1 4,7 .1 11,18 .1} 13,16 .0 3,8 .0 12 ^{, 17]} Dokosanjiiru group, methyl octa cyclo [8.8.0.1 ^2,9 .1
^4,7 .1 ^11,18 .1 ^13,16 .0 ^3,8 .0 ^12,17] Although such Dokosanjiiru group, the present invention is not limited thereto. Examples of the substituent of the substituted bridged cyclic hydrocarbon group include an alkyl group, a halogen atom, an alkoxy group, a thioalkyl group, and a nitrile group.

Where R^TwoSpecific examples of
Tyl group, n-propyl group, isopropyl group, n-butyl
Straight-chain, isobutyl, t-butyl, etc.
Is a branched alkyl, cyclohexyl, tricyclo
[5.2.1.0^2,6Decyl group, adamantyl group, norborny
Group, isobornyl group, tetracyclo [4.4.0.1^2,5.1
^7,10Alicyclic hydrocarbon group such as dodecyl group, phenyl
Groups, benzyl, naphthyl, anthranyl, etc.
Aromatic groups, but the invention is not limited thereto
Not. In particular, substituted alkyl groups, substituted alicyclic hydrocarbons
And a substituent of the substituted aromatic group includes a halogen atom,
Alkyl group, alkoxy group, thioalkyl group, nitrile
And the like.

A method for producing the vinyl monomer represented by the general formula (1) is disclosed in Japanese Patent No. 2856116,
-171122 and JP-A-10-287712.

In order to maintain good performance of the optical transparent resin material, it is preferable that the polymer is a main component of the optical transparent resin material, specifically, the optical transparent resin material of the polymer. Is preferably 50 to 100% by weight, and more preferably 70 to 100% by weight.

In the present invention, the monomer composition of the polymer is preferably 100 to 5% by weight of a vinyl monomer and 0 to 95% by weight of another copolymerizable monomer. In this manner, the excellent properties of the monomer represented by the general formula (1) can be sufficiently utilized to obtain an optically transparent resin material of excellent quality.

The weight-average molecular weight of the polymer is determined by dissolving the transparent resin material for optical use in a good solvent such as tetrahydrofuran (THF) or acetone, and using a light scattering method or a gel permeation chromatogram method. In order for the optical transparent resin material to have sufficient mechanical strength and moldability,
The weight average molecular weight is preferably from 1,000 to 1,000,000, and more preferably from 1,000 to 500,000.

The properties other than the molecular weight of the polymer are specified as follows. First, the ratio of repeating structural units is
It is determined by the monomer composition of the polymer. As for the monomer composition of the polymer of the present invention, the proportion of the vinyl monomer is preferably 100 to 5% by weight, more preferably 10 to 5% by weight.
0 to 30% by weight. Within this range, the excellent properties of the monomer represented by the general formula (1) can be fully utilized to obtain a transparent optical resin material of excellent quality. Regarding the arrangement state of repeating units in the polymer such as randomness and blockiness, and stereoregularity,
There is no particular limitation as long as it is within the range described below, and any form may be used.

The arrangement state and stereoregularity of the repeating unit are as follows:
It is specified by total light transmittance, saturated water absorption and glass transition temperature. In order to use the optical transparent resin material of the present invention in an optical lens, an optical fiber, an optical disk for an information recording medium using a laser beam, an advanced optical element such as an optical waveguide circuit, the physical properties of these materials are required. It is preferable that the requirements to be expressed fall within the following ranges. The total light transmittance is an index of the transmittance of white light in the optical transparent resin material and corresponds to the transparency, and is measured according to ASTM1003. The total light transmittance is preferably 8
5% or more, more preferably 90% or more. The saturated water absorption was determined by measuring a cast plate of a transparent resin material for optical
After drying under reduced pressure for 8 hours, the initial weight (dry weight) is measured. Then, the cast plate is immersed in warm water at 80 ° C. for 48 hours, and then the weight (water absorption weight) is determined by the following equation. Saturated water absorption (%) = [(water absorption-dry weight) / (dry weight)] × 100 In the polymer of the present invention, the value of the saturated water absorption determined as described above may be 2% or less. It is more preferably 1% or less. Most preferably, it is 0.4% or less. The glass transition point is a temperature at which the polymer starts micro-Brownian motion, and is a physical property value directly connected to the arrangement state and stereoregularity of the repeating unit, and is an index of heat resistance. The measurement is performed by differential scanning calorimetry (DSC) at a heating rate of 5 ° C./min under a nitrogen atmosphere. The glass transition temperature is preferably 120 ° C. or higher, more preferably 13 ° C.
0 ° C. or higher, most preferably 140 ° C. or higher.

In the present invention, the copolymerizable monomer may contain a (meth) acrylate derivative.
Specific examples of the (meth) acrylate derivative include methyl (meth) acrylate, ethyl (meth) acrylate,
Isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate,
Isobutyl (meth) acrylate, t-butyl (meth)
Alkyl (meth) acrylate such as acrylate, cyclohexyl (meth) acrylate, norbornyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecyl (meth) acrylate, tetracyclododecyl (meth) acrylate, etc. Alicyclic (meth) acrylate,
Examples include aromatic (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, and naphthyl (meth) acrylate, but the present invention is not limited thereto. In particular, from the viewpoint of low water absorption, an alicyclic (meth) acrylate is preferable. By copolymerizing these copolymerizable compounds, optical properties, water absorption,
It is possible to balance heat resistance, adhesiveness, moldability, mechanical strength, economy, and the like.

In the present invention, the other copolymerizable monomer may contain an aromatic vinyl derivative. Specific examples of the aromatic vinyl derivative include α-substituted styrene such as styrene and α-methylstyrene, and nuclear-substituted styrene such as methylstyrene and methoxystyrene, but the present invention is not limited thereto. By copolymerizing these copolymerizable compounds, optical properties, water absorption, heat resistance, adhesion, further mechanical strength, moldability,
It is possible to balance economics and the like.

In the present invention, the other copolymerizable monomer may contain an unsaturated dibasic acid derivative. Specific examples of unsaturated dibasic acid derivatives include maleic anhydride,
Examples include N-substituted maleimides such as N-methylmaleimide, N-ethylmaleimide, and N-phenylmaleimide, but the invention is not limited thereto. By copolymerizing these copolymerizable compounds, optical properties, water absorption, heat resistance, adhesion, further mechanical strength, moldability,
It is possible to balance economics and the like.

In the present invention, the other copolymerizable monomer may contain an unsaturated fatty acid derivative. Specific examples of the unsaturated fatty acid derivative include (meth) acrylic acid,
Examples include acrylamide, methacrylamide, N-dimethylacrylamide, and the like, but the invention is not limited thereto. By copolymerizing these copolymerizable compounds, it becomes possible to balance optical properties, water absorption, heat resistance, adhesiveness, mechanical strength, moldability, economy and the like.

The optical transparent resin material of the present invention is synthesized by a known polymerization method such as radical polymerization or ionic polymerization. For example, solution polymerization in the presence of a polymerization initiator, bulk polymerization,
It is synthesized by a method such as suspension polymerization.

Examples of the initiator used for the polymerization include lauroyl peroxide, benzoyl peroxide, t-butylperoxypivalate, t-butylperoxyneodecanate, t-butylperoxy-2-ethylhexanoate, and t-butylperoxy-2-ethylhexanoate. Organic peroxides such as -butylperoxyisobutyrate, 2,2′-azoisobutyronitrile,
Azo compounds such as 2′-dimethyl-azoisobutyrate and 2,2′-azobis (2-methylbutyronitrile);
Examples thereof include a water-soluble catalyst represented by potassium persulfate and ammonium persulfate, and a redox catalyst obtained by combining a peroxide or a persulfate with a reducing agent. These polymerization initiators can be used alone or in combination of two or more.

The amount of these polymerization initiators to be added is as follows.
It is used in the range of 0.01 to 10 parts by weight with respect to 00 parts by weight. The polymerization temperature is usually in the range of 40 to 160 ° C., and the polymerization can be carried out in multiple stages by changing the polymerization temperature. In particular, in the case of mold polymerization, the mold used is not particularly limited.For example, a mold composed of a plate-like material such as tempered glass, a stainless steel plate, and a chrome-plated plate and a soft vinyl chloride gasket is preferably used. You.

Since the optical transparent resin material of the present invention contains a polymer having a specific structure as a main component, it has the following functions and effects.

First, since the vinyl monomer has a hydrophobic group represented by -Z-, the resulting polymer has poor hygroscopicity, and the optical transparent resin material has low water absorbing property. Is shown.
Secondly, vinyl monomers, represented by -COOR ^2,
Since the molecule has a polar group composed of a carboxylic acid or a carboxylic acid ester, an attractive force is generated between the polymer chains of the obtained polymer, and the glass transition temperature increases. Therefore, the optical transparent resin material exhibits excellent heat resistance. Third, since an electrostatic interaction acts between the polar group and Al, excellent adhesion between the optical transparent resin material and Al can be realized. When manufacturing optical disks using optical transparent resin materials,
Adhesion with Al is a particularly important property. Al is deposited on one side of the disk and reflects the laser light. Therefore, the surface smoothness and long-term stability of the Al film are important, and the presence of the polar group represented by -COOR ² in the vinyl monomer improves the adhesion between the disk and the Al film, Good surface smoothness and long-term stability of the Al film can be realized. Furthermore, since the optical transparent resin material disclosed in the present invention is based on polymethyl methacrylate resin, relatively good optical characteristics can be expected, but the vinyl monomer is a flexible resin represented by -Z-. Group,
The obtained polymer has more excellent isotropy, and as a result, the optical transparent resin material has further improved low dispersibility and low birefringence.

[0029]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

(Example 1) 200 m equipped with a three-way cock
methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10] eggplant flask l dodecyl methacrylate 50g of 2,2'-azobisisobutyronitrile 0.1g was added, under argon, at 60 ° C. Stir for 30 minutes,
A partial polymer was obtained. Next, this partial polymer was poured into a glass cell and polymerized at 60 ° C. for 4 hours and further at 120 ° C. for 7 hours to obtain a transparent cast plate having a thickness of 3 mm.

[0031] (Example 2-4, Comparative Example 1-3) methoxycarbonyltetracyclo [4.4.0.1 ^2,5 .1 ^7,10] in place of dodecyl methacrylate 50 g, polymerizing the monomers shown in Table 1 Thus, a cast plate was produced. The procedure was the same as in Example 1 except that the type of monomer and the amount charged were different.

[0032]

[Table 1] (Evaluation of properties of cast plate) Examples 1-4, Comparative Examples 1-3
The weight average polymerization degree, the refractive index, the total light transmittance, the saturated water absorption, and the glass transition temperature of the cast plate obtained in the above were measured, and the adhesiveness of Al was further evaluated. The implementation method was as follows, and the results are summarized in Table 2.

Weight-average degree of polymerization: The cast plate was dissolved in tetrahydrofuran and determined by gel permeation chromatography. The chromatographic equipment used was L manufactured by Shimadzu Corporation.
C-9A, and the column is KF-80M manufactured by Showa Denko KK

Refractive index: Measured according to a conventional method using an Abbe refractometer 2T manufactured by Atago.

Total light transmittance: The transmittance of white light was measured using an integrating sphere measuring device ISR-365 manufactured by Shimadzu Corporation.
It was measured according to TM1003.

Saturated water absorption: The cast plate was dried under reduced pressure at 60 ° C. for 48 hours, the initial weight (dry weight) was measured, and then the cast plate was immersed in warm water at 0 ° C. for 48 hours, and then weighed (water absorption). Weight) and the following equation. Saturated water absorption (%) = [(water absorption weight−dry weight) / (dry weight)] × 100 Glass transition temperature: DSC3100 manufactured by Mac Science
Was measured by differential scanning calorimetry (DSC) at a heating rate of 5 ° C./min in a nitrogen atmosphere.

Al adhesion: Aluminum was deposited on the surface of the cast plate, and the formed aluminum deposited layer was then rubbed.

[0038]

[Table 2] Table 2 shows that in Examples 1 to 4, cast plates having the same molecular weight, refractive index, and total light transmittance were obtained as compared with the comparative example. That is, the mechanical properties, moldability, and optical properties of the optical transparent resin material disclosed in the present invention are as excellent as those of conventional materials, and can be easily manufactured by a known method. On the other hand, as for the saturated water absorption, especially when compared with Comparative Example 1, it can be seen that the saturated water absorption of the cast plates shown in Examples 1 to 4 was low, that is, the water absorption was reduced. Similarly, with respect to the glass transition temperature, it can be seen that the present invention is superior to Comparative Examples 1 and 2, that is, the heat resistance is improved. From the above, it was shown that the transparent resin material for optical shown in the present invention has improved water absorption and heat resistance in a well-balanced manner while maintaining good optical and mechanical properties. Furthermore, in the comparative example, in particular, in the case of Comparative Example 3, the Al layer was easily peeled off, whereas in the cast plates of Examples 1 to 4, the deposited Al layer was not easily peeled off. The adhesion was shown to be improved. In conclusion, when including the adhesiveness with Al, Comparative Examples 1 to 3 are unsatisfactory in any of the properties, while Examples 1 to 4 have all properties improved in a well-balanced manner. It is a suitable value. Therefore, the optical transparent resin material disclosed in the present invention is compared with a known optical transparent resin material, and is compared with a known optical transparent resin material, such as an optical lens, an optical fiber, an optical disk for an information recording medium using a laser beam, and an optical waveguide circuit. It was found that it can be suitably used for a typical optical element.

[0039]

Vinyl monomer according to the present invention is a hydrophobic group represented by -Z-, represented by -COOR ^2, since the polar group consisting of carboxylic acids and carboxylic acid esters has in the molecule The optical transparent resin material shown in the present invention has excellent optical properties, low water absorption, high heat resistance, and good adhesiveness. Further, the optical transparent resin material has excellent mechanical properties and moldability, and can be easily produced by a conventional method conventionally used. Therefore, the optical transparent resin material of the present invention is suitably used as a material for advanced optical elements such as optical lenses, optical fibers, optical disks for information recording media using laser light, and optical waveguide circuits.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Etsuo Hasegawa 5-7-1 Shiba, Minato-ku, Tokyo F-term within NEC Corporation (reference) 4J100 AL03Q AL04Q AL08P AL08Q AL11Q BA04P BA16P BA20P BA40P BA53P BB00P BC04P BC04Q BC08P BC08Q BC09P BC09Q BC12P BC12Q BC43P BC43Q BC48P BC49P BC49Q CA04 JA33 JA36

Claims (6)

[Claims] 1. A polymer obtained by polymerizing the vinyl monomer represented by the general formula (1) alone or together with another monomer copolymerizable with the vinyl monomer. Optical transparent resin material as the main component. Embedded image (Wherein, R ¹ is a hydrogen atom or a methyl group, Z is a substituted or unsubstituted bridged cyclic hydrocarbon group having 7 to 23 carbon atoms.
R ² is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 6 to 13 carbon atoms, or a substituted or unsubstituted Represents a substituted aromatic group having 6 to 14 carbon atoms. ) 2. The polymer according to claim 1, wherein the vinyl monomer
The optical transparent resin material according to claim 1, which is a polymer obtained by polymerizing 0 to 5% by weight and 0 to 95% by weight of the other monomer. 3. The optical transparent resin material according to claim 1, wherein the other monomer contains a (meth) acrylate derivative. 4. The optical transparent resin material according to claim 1, wherein the other monomer contains an aromatic vinyl derivative. 5. The optical transparent resin material according to claim 1, wherein the other monomer contains an unsaturated dibasic acid derivative. 6. The optical transparent resin material according to claim 1, wherein the other monomer contains an unsaturated fatty acid derivative.