JPH0614413B2 - Optical disc material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention also relates to an optical disk material. More specifically, the present invention relates to an optical disk material having excellent heat resistance and transparency and having a small birefringence.

[Conventional technology and problems]

In recent years, the demand for plastic materials as optical element materials is expanding, and currently transparent resins such as polymethylmethacrylate, polystyrene, and polycarbonate are used as optical element materials, but both have poor heat resistance and dimensional stability. There is.

The properties required of the optical disc material are dimensional stability and heat resistance under environmental conditions.

The most frequently used material for optical disc substrates for injection molding is polymethylmethacrylate resin.
Polycarbonate resins are also in practical use, but they are not suitable for large-sized disks and have excellent heat resistance, but have poor moldability and large birefringence due to molding strain.

Polymethylmethacrylate and polystyrene have excellent moldability, but have poor heat resistance and cannot withstand use under high temperature conditions. In addition, polymethylmethacrylate is particularly excellent in optical characteristics, but has a drawback that it has a large elongation due to moisture absorption, it greatly warps when a reflecting film is provided on one side, and the focus surface is deformed by the thermal energy of laser light. .

[Means for solving problems]

The present inventors have studied for the purpose of solving the above-mentioned drawbacks, and as a result, the imidized copolymer having a specific composition has the same refractive index as the aromatic polycarbonate, and the imidized copolymer and the aromatic polycarbonate are combined. It was found that this improves the moldability.

Moreover, it has been found that a resin composition having a very small photoelastic coefficient can be obtained by combining a polycarbonate and an imidized copolymer. It has been found that an optical disk made of this resin composition is excellent in heat resistance and transparency, has a small residual stress due to molding, and has a small photoelastic coefficient, so that an optical disk having a small birefringence can be obtained.

That is, the present invention provides (A) component: aromatic vinyl monomer residue 30 to 80% by weight,
The total amount of the N-phenylmaleimide monomer residue and the N-methylmaleimide monomer residue is 20 to 70% by weight and the vinyl monomer residue other than these is 0 to 40% by weight.
A phenylmaleimide monomer residue and an N-methylmaleimide monomer residue in a molar ratio of 65-35 / 35-65 in excess of 30% by weight to 95% by weight, Component B): An optical disc material comprising 5% by weight or more and less than 70% by weight of an aromatic polycarbonate.

In the present invention, the optical disc specifically includes a video disc, an audio disc, and a file disc.

First, the method for producing the imidized copolymer as the component (A) will be described.

The first method for producing the component (A) copolymer is an aromatic vinyl monomer, N-phenylmaleimide monomer, N-
A method of copolymerizing a methylmaleimide monomer and a vinyl monomer mixture copolymerizable therewith, as a second production method, an aromatic vinyl monomer, maleic anhydride, and a vinyl monomer copolymerizable therewith. A method in which a polymer obtained by copolymerizing a monomer mixture is reacted with aniline and methylamine to convert an acid anhydride group into an imide group, and an imidized copolymer can be obtained by any method .

The amount of aniline and methylamine used was 0.65 to 0,0 for aniline / methylamine based on maleic anhydride.
35 / 0.35-0.65 mol.

The aromatic vinyl monomer used in the first and second production of the component (A) copolymer is a styrene monomer such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene and the like. And a substituted monomer thereof, and of these, styrene is particularly preferable.

As other vinyl monomers, acrylonitrile, methacrylonitrile, vinyl cyanide monomers such as α-chloroacrylonitrile, acrylic acid ester monomers such as methyl acrylic acid ester, ethyl acrylic acid ester,
There are methacrylic acid ester monomers such as methyl methacrylic acid ester and ethyl methacrylic acid ester, vinylcarboxylic acid monomers such as acrylic acid and methacrylic acid, acrylic acid amide, and methacrylic acid amide.

In particular, in the case of the first production method, it is preferable to copolymerize an unsaturated dicarboxylic acid anhydride such as maleic anhydride used in the second production method.

When the imidization reaction of the second production method is carried out in a solution state or a suspension state, it is preferable to use an ordinary reaction vessel, for example, an autoclave, and when it is carried out in a bulk molten state, an extruder equipped with a devolatilization device is used. May be used. A catalyst may be present during imidization, and for example, a tertiary amine or the like is preferably used.

The temperature of the imidization reaction is room temperature to 350 ° C, preferably 100 to 300 ° C.

When the amount of the aromatic vinyl monomer residue is less than 30% by weight, moldability and dimensional stability are impaired, and when it exceeds 80% by weight, impact strength and heat resistance are impaired. If the amount of the maleimide derivative residue is less than 20% by weight, the effect of improving the heat resistance is not sufficient, while if it exceeds 70% by weight, the resin composition becomes brittle and the moldability remarkably deteriorates. Further, the ratio of the N-phenylmaleimide monomer residue and the N-methylmaleimide monomer residue in the maleimide derivative acid group is 65 in molar ratio.
35/35 to 65/35, and when it exceeds 65/35, the refractive index becomes larger than that of aromatic polycarbonate.
When it is less than the above value, it is smaller than the aromatic polycarbonate and the transparency is poor when combined with the aromatic polycarbonate.

As the polycarbonate resin used as the component (B),
In general And has a repeating unit of, for example, a phosgene method or a transesterification method.

Preferred polycarbonate resins are bis (hydroxyaryl) alkane-based polycarbonate resins, such as bis (4-hydroxyphenyl)
Methane, bis (4-hydroxyphenyl) ethane, 2,2
-Bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenylpropane, bis (4-hydroxyphenyl) phenylmethane or other bis (hydroxyaryl) alkane and phosgene or It is obtained from a diaryl carbonate and these are used alone or as a mixture.

In the present invention, the ratio of the component (A) and the component (B) is such that the component (A) is 3
It is more than 0% by weight and up to 95% by weight, and the component (B) is 5% by weight or more and less than 70% by weight. The composition of the component (A) and the component (B) within this range has good moldability, optical properties, mechanical properties (strength) and heat resistance, and is suitable as an optical disc material.

In the present invention, the mixing method of the component (A) and the component (B) is not particularly limited, and known means can be used.

Examples of the means include a Banbury mixer, a Henschel mixer, a tumbler mixer, a single-screw or twin-screw extruder, and the like.

(Example) All parts and% in the examples are expressed on a weight basis.

Experimental Example (1) Manufacture of a polymer obtained by imidizing a copolymer obtained by polymerizing an aromatic vinyl monomer and maleic anhydride Charge 100 parts of styrene and 50 parts of methyl isobutyl ketone into an autoclave equipped with a stirrer. The delivery was replaced with nitrogen gas. After raising the temperature to 83 ° C., maleic anhydride 67
And 0.2 parts of benzoyl peroxide were dissolved in 400 parts of methyl isobutyl ketone and added over 8 hours. As a result of sampling a part of the viscous reaction liquid and quantifying the unreacted monomer by gas chromatography, the polymerization rates were 99% for styrene and 99% for maleic anhydride.
The maleic anhydride was added to the copolymer solution obtained here.
32 parts of 0.5 molar equivalents of aniline, 11 parts of 0.5 molar equivalents of methylamine and 1 part of triethylamine with respect to maleic anhydride were added and reacted at 140 ° C. for 7 hours. The imidized copolymer obtained by the degassing treatment is referred to as polymer A-1.

Experimental Example (2) Production of a polymer obtained by imidizing a copolymer obtained by polymerizing aromatic vinyl, maleic anhydride, and a vinyl monomer copolymerizable therewith, styrene instead of 100 parts of styrene in Experiment (1). A copolymer was obtained in the same manner as in Experimental Example (1) by using 100 parts and 17 parts of acrylonitrile and making 50 parts of 67 parts of maleic anhydride. The polymerization rate of this polymer is 98% styrene and 98% maleic anhydride.
It was in%.

The same operation as in Experimental Example (1) was performed except that 24 parts of aniline and 8 parts of methylamine were used in the resulting copolymer solution to obtain an imidized copolymer. This is designated as Polymer A-2.

Experimental Example (3) In Experimental Example (1), 32 parts of aniline at 0.5 molar equivalents and 11 parts of methylamine at 0.5 molar equivalents were replaced with 29 parts of aniline at 0.45 molar equivalents and methylamine 1 at 0.45 molar equivalents.
The procedure was the same as in Experimental Example (1) except that 0 part was used. The obtained imidized copolymer is designated as A-3.

Examples 1 to 3 Polymer A-1 obtained in Experimental Example (1) and a polycarbonate resin (Panlite L-1225, Teijin Chemicals Ltd.)
After mixing at the ratios shown in the table, they were extruded into pellets by an extruder with a vent. This pellet is 1.2m thick by injection molding.
A disk of m and 120 mm in diameter was molded and evaluated. First result
Shown in the table.

Example 4 The procedure of Example 1 was repeated except that the polymer A-2 obtained in Experimental Example (2) was used.

Example 5 Using the imidized copolymer A-3 obtained in Experimental Example (3), the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 6 35 parts by weight of the polymer A-1 obtained in Experimental Example (1) and 65 parts by weight of a polycarbonate resin were mixed, pelletized in the same manner as in Example 1, and the pellet was molded into a disk. Evaluated. The results are shown in Table 1.

Comparative Example 1 Example 1 was repeated except that only the polycarbonate resin was used.

Comparative Example 2 32 parts of aniline and 1 of methylamine in Experimental Example (1)
Polymer A-4 was obtained in the same manner as in Experimental Example (1) except that 64 parts of aniline was used instead of 1 part.

The procedure of Example 1 was repeated except that the polymer A-4 was used instead of the polymer A-1. The results are shown in Table 1.

The methods for measuring the physical properties shown in the table were as follows.

(1) VSP: Load 5 kg Compliant with ASTM D-1525 (2) Light transmittance: Compliant with JIS K 6714 (3) Optical path difference: Measured with an automatic ellipsometer.

(Effects of the Invention) As described in detail above, the resin composition of the present invention is excellent in heat resistance and transparency, has a good moldability, and is capable of obtaining a molded product having a small optical distortion.

Claims (1)

[Claims] 1. Component (A): aromatic vinyl monomer residue 30 to 80
%, The total amount of N-phenylmaleimide monomer residue and N-methylmaleimide monomer residue is 20 to 70% by weight, and 0 to 40% by weight of vinyl monomer residue other than these. A phenylmaleimide monomer residue and an N-methylmaleimide monomer residue in a molar ratio of 65-35 / 35-65 in excess of 30% by weight to 95% by weight (B ) Component: An optical disc material comprising 5% by weight or more and less than 70% by weight of aromatic polycarbonate.