JP3130165B2 - Transparent resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is useful for preparing a transparent resin composition having an arbitrary refractive index, particularly an optical resin having an arbitrary refractive index, wherein a resin and a monomer are polymerized. Is
The present invention relates to a resin composition comprising:

2. Description of the Related Art With the rapid progress of electronic devices such as optical devices and semiconductor lasers, optical communication systems have been put into practical use, and optical fibers are the basis of such optical communication systems. As optical fibers, silica-based optical fibers, multi-component glass-based optical fibers, plastic-based optical fibers, and the like have been developed, and various optical cables using these optical fibers have been commercialized.

An optical fiber is composed of a high-refractive-index core and a low-refractive-index clad (sheath). It is classified into a graded index type having a continuous refractive index distribution from the center to the periphery.

In addition, research on optical components, for example, gradient index lenses and optical devices, has been actively conducted along with information transmission means centered on optical fibers. In the field of optoelectronics, these optical components have been developed. It is expected to play an important role in the future. In the field of optical materials as described above, materials capable of adjusting the refractive index to desired ones are expected.

[0005]

2. Description of the Related Art As described above, among optical fibers, silica-based optical fibers and multi-component glass-based optical fibers are often used for long-distance transmission. It has the characteristic of having optical transmission characteristics, but has the disadvantage of being brittle. On the other hand, although plastic optical fibers have inferior optical transmission characteristics to glass optical fibers, they can be made into large-diameter optical fibers and have excellent workability, so they have been commercialized for short-distance transmission. I have. Also, recently, a plastic clad optical fiber having a quartz or glass core and a plastic clad is expected to have characteristics as an optical fiber for medium-distance transmission.

The core material of the plastic optical fiber is represented by polymethyl methacrylate resin, polystyrene resin, polycarbonate resin, poly-4-methylpentene-1, deuterated polymethyl methacrylate, deuterated polystyrene and the like. It is made of a transparent and high refractive index organic polymer material. Also, as the cladding material, silicon-based and fluorine-based resins having a lower refractive index are often used, and in particular, for the fluorine-based resin,
Attention has been paid to the fact that the weather resistance is good in accordance with the low refractive index. For example, JP-A-49-107790, JP-A-49-108321, and JP-A-49-1
These sheath materials are specifically shown in JP-A-15556, JP-A-51-52849 and JP-A-53-60242.

However, the fluororesin used as the cladding material is often a single polymer material such as a fluoroalkyl (meth) acrylate-based resin or a vinylidene fluoride-based copolymer. Poor compatibility with resin, opaque by resin blending,
The diversification of required performance cannot be handled by modifying these resins. For this reason, performance improvement can be expected by blending these resins, etc.
Almost no examples have been known in which a resin composition in which different resins are blended is applied to a cladding material of an optical fiber or an optical device.

Recently, examples of resin mixtures having excellent compatibility include:
JP-A-59-41348, JP-A-59-6245
JP, JP-A-62-57449 and the like,
It is described that the resin composition is suitable for a wide range of applications in the optical field, but it is difficult to adjust the refractive index of these resin compositions to a desired one, and the molded product has sufficient transparency and mechanical strength. Almost nothing has been developed. As a transparent composition in a resin blend system, only a blend of a vinylidene fluoride resin and a vinyl ester copolymer is known, and a method of kneading each polymer in a molten state is known as a production method thereof. There is a method in which the two types of polymers are dissolved in a common solvent, mixed, and then the solvent is removed.

A blend system of a vinylidene fluoride resin and a vinyl ester copolymer has a drawback that the range in which the refractive index can be adjusted is narrow, and a resin which can adjust the refractive index in a wider range and has excellent transparency. System development,
The present inventors have studied a variety of polymer blends having different refractive indices and methods for producing the blends, and have disclosed in Japanese Patent Application Nos. 63-118134 and 62-26.
No. 2725, Japanese Patent Application No. 62-294220, Japanese Patent Application No. 63
-118133 and Japanese Patent Application No. 1-281725. The heat resistance of these resin blends was not so good as compared with the blend of vinylidene fluoride resin and vinyl ester copolymer.

[0010]

Means for Solving the Problems The inventors of the present invention have studied for the purpose of obtaining a resin composition which can adjust the refractive index in a wider range and has higher heat resistance. Polymer as main component (A)
And a monomer (B) containing adamantyl (meth) acrylate as a main component, which gives a polymer having a higher refractive index than that of the polymer (A), mixed with a polymerization initiator.
The present invention, which is a transparent resin composition, has been completed.

[0011] monomers that may be used to make the polymer of higher refractive index than the polymer used in the practice of the present invention (A)
As the isomer (B) , a monomer mixture containing adamantyl (meth) acrylate in an amount of 10% by weight or more is preferably used. As a monomer used together with the adamantyl (meth) acrylate, methyl (meth) acrylate is used. ) Acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, tert-butyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and other alicyclic (meth) A) acrylate and the like. Fluorinated alkyl (meth) acrylates can also be used as long as the polymer obtained from the monomer mixture has a higher refractive index than the polymer (A). Polymerization of adamantyl (meth) acrylate monomer (B)
The amount in the body is preferably in the range of 10 to 68% by weight. Adamantyl (meth) acrylate large amount of copolymerized polymer impairs the compatibility of the polymer (A) late
There is .

Further, as the polymer (A) containing methyl methacrylate as a main component used in the present invention, a homopolymer of methyl methacrylate may be used, or a copolymer of methyl methacrylate and another copolymerizable monomer may be used. A copolymer may be used. Such monomers include methyl acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, tert-butyl (meth) acrylate, benzyl (meth) acrylate, and phenyl (meth) acrylate. Acrylate, 2-hydroxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, 2- (n-butoxyethyl) (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate,
2,2,2-trifluoroethyl (meth) acrylate, 2,2,
3,3-tetrafluoropropyl (meth) acrylate, 2,
2,3,3,3-pentafluoropropyl (meth) acrylate, 1-trifluoromethyl-2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3,4,4,5, (Meth) acrylates such as 5-octafluoropentyl (meth) acrylate, 2,2,3,3,4,4-hexafluoro (meth) acrylate, and other alicyclic (meth) acrylates.

The polymer (A) obtained by copolymerizing a monomer having a lower refractive index than methyl methacrylate among these monomers with methyl methacrylate has a lower refractive index than that of methyl methacrylate homopolymer. Although the range of the refractive index that can be adjusted for the transparent resin composition becomes large,
The compatibility between both polymers (A) and (B) tends to be poor, and care must be taken not to impair the transparency.

Further, a copolymer of a monomer having a higher refractive index than methyl methacrylate and methyl methacrylate has a higher refractive index than that of methyl methacrylate homopolymer, and the resin composition of the present invention using this polymer has a higher refractive index. Although the adjustable refractive index range is small, both polymers (A),
The compatibility between (B) tends to be better. Therefore, the selection of the type of monomer having a lower refractive index than that of methyl methacrylate used in producing the polymer (B) and the copolymerization amount thereof are within a range that does not impair the compatibility of the polymers (A) and (B). It is necessary to.

The polymer (B) constituting the resin composition of the present invention
Is required to be 25 to 75% by weight. Resin compositions formed from compositions outside this range tend to have poor compatibility and tend to whiten.

[0016] The resin composition of the present invention is a polymer (A), heavy
By preparing a composition with the monomer (B) composing the coalescing and polymerizing it, it is considered that an internetwork polymer structure is formed between both polymers, and a resin composition having good transparency Things. Thermal polymerization method as the polymerization method,
A photopolymerization method is preferred, and a photopolymerization method is particularly preferred. As the polymerization catalyst, for example, carbonyl compounds such as benzoin, benzoin isobutyl ether, benzyl, benzophenone, p-methoxybenzophenone, 1-hydroxycyclohexyl phenyl ketone, sulfur compounds such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, azobis Azo compounds such as isobutyronitrile and azobis-2,4-dimethylvaleronitrile;
Peroxide compounds such as benzoyl peroxide and di-tert-butyl peroxide are included. Further, a photosensitizer can be used together with the photopolymerization initiator.

In order to prepare the resin composition having the desired refractive index, transparency and heat resistance of the present invention, a polymer (A) containing methyl methacrylate as a main component and a polymer (A) having a higher molecular weight than the polymer (A) are used. It is most important to use a mixture of a monomer (B) containing, as a main component, adamantyl (meth) acrylate that gives a polymer having a refractive index in a state of good compatibility. It is preferable to use a method in which a photopolymerization catalyst is added, mixed well, and irradiated with light such as ultraviolet light to carry out polymerization curing treatment.

When a monomer mainly containing adamantyl methacrylate is used as the monomer (B) in the present invention, the glass transition temperature (Tg) of the homopolymer is as high as 170 ° C., and the glass transition temperature (Tg) of the adamantyl acrylate is high. 1
15 ℃ or methyl methacrylate homopolymer (Tg) 1
It is preferable because the resin composition of the present invention having a Tg higher than 10 ° C. can be obtained, and its hygroscopicity can be low.

[0019]

The resin composition of the present invention is a polymer having a low refractive index.
(A) and a polymer having a high refractive index (B) to form an internetwork polymer structure, and the mixing ratio is appropriately adjusted within a range not to impair the compatibility. As a result, a novel transparent resin composition having a desired refractive index can be obtained.
Further, this resin composition can be used as a sheath material or a core material for an optical fiber, and further, as a graded index type optical fiber material.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[0021]

Example 1 Polymethyl methacrylate (n _D = 1.489,
[Η] = 0.425, measured in MEK at 25 ° C., the same applies hereinafter) A mixture comprising 40 parts by weight, adamantyl methacrylate 32 parts by weight, methyl methacrylate 28 parts by weight, and 1-hydroxycyclohexyl phenyl ketone 0.5 part by weight was prepared. Was sandwiched between two polyester films, and irradiated with ultraviolet rays at 25 ° C. to obtain a transparent film. The refractive index of this film was 1.503, and the light transmittance was 91%. The glass transition temperature (Tg) of this film is 1
29 ° C.

[0022]

Comparative Example 1 A polymer composed of 53% by weight of adamantyl methacrylate and 47% by weight of methyl methacrylate (n _D = 1.5
13, [η] = 0.350) 60 parts by weight and polymethyl methacrylate (n _D = 1.489, [η] = 0.425) 40 parts by weight were dissolved in methyl ethyl ketone 900 parts by weight. This solution was flowed on a film to a thickness of 0.1 mm, after which methyl ethyl ketone was volatilized. At that time, the film turned white.

[0023]

Example 2 Polymethyl methacrylate (n _D = 1.489,
[Η] = 0.425) 45 parts by weight, adamantyl acrylate 30
A mixture consisting of 25 parts by weight of methyl methacrylate, 0.8 part by weight of 1-hydroxycyclohexyl phenyl ketone was prepared, and the mixture was sandwiched between two polyester films and irradiated with ultraviolet rays at 30 ° C. to obtain a transparent film. Was. The refractive index of this film is 1.503,
The light transmittance was 92%. The glass transition temperature (Tg) of this film was 113 ° C.

[0024]

Examples 3 to 6 A polymer comprising 98% by weight of methyl methacrylate and 2% by weight of methyl acrylate (n _D = 1.489,
[Η] = 0.335) and adamantyl methacrylate 59% by weight
And a monomer mixture of 41% by weight of methyl methacrylate and 1.0% by weight of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator. The mixture was mixed as shown in [Table 1]. Perform photopolymerization in the same manner,
The results of measuring the physical properties of the obtained resin composition are shown in Table 1.

[Table 1]

[0025]

Examples 7 to 9 Polymers comprising 98% by weight of methyl methacrylate and 2% by weight of methyl acrylate (n _D =
1.489, [η] = 0.335) and the following monomer mixture at a mixing ratio of 50:50.
Hydroxycyclohexyl phenyl ketone 1.0% by weight
Table 2 shows the results of evaluating the properties of the resin composition obtained by photopolymerizing the product obtained by adding the above. However, the monomer mixture used was a mixture of methyl methacrylate (C) and adamantyl methacrylate (D) at a mixing ratio shown in [Table 2].

[Table 2]

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 265/06 B29D 11/00 C08J 5/00 C08F 20/18 B29K 33:04

Claims (2)

(57) [Claims] 1. A polymer (A) containing methyl methacrylate as a main component in an amount of 25 to 75% by weight, and a monomer (A) containing adamantyl (meth) acrylate having a higher refractive index than the polymer (A) as a main component. B) A transparent resin composition obtained by polymerizing a mixture of 75 to 25% by weight. 2. The monomer mixture according to claim 1, wherein the monomer (B) comprises 10 to 68% by weight of adamantyl (meth) acrylate and 90 to 32% by weight of another copolymerizable monomer. Transparent resin composition.