JPH0356511A - Polystyrene-based copolymer and resin composition therefrom - Google Patents

Abstract

PURPOSE:To obtain the title copolymer capable of giving transparent optical materials excellent in light transmittance and mechanical strength with small optical strain through blending with polycarbonate resin, thus suitable for optical disks and lens by grafting a carbonate compound to a polystyrene-based resin as the backbone polymer. CONSTITUTION:The objective copolymer having recurring units of formulas I and II { Z is of formula III or IV [ m is 1 - 10; R<1> is H, 1-12C alkyl, phenyl, cumyl, phenoxy, benzoyl or of formula V (R<2> is 1-4C alkyl ) ] }, respectively, with the molar ratio of the unit I to the unit II : x/y being such as to be 0.03 - 0.5 in y/( X + Y). The other objective resin composition can be obtained by blending 10 - 95 wt.% of the present copolymer with 90 - 5 wt.% of polycar bonate resin.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a polystyrene copolymer suitable for use as a material for optical transparent shaped articles such as optical discs and lenses, and a resin composition comprising the copolymer. relating to things.

[Prior Art] It is known that acrylic resin is used as a material for optical transparent molded products because it has characteristics such as good fluidity and low birefringence (Japanese Unexamined Patent Application Publication No. 1983-1991). -13165
Publication No. 4, etc.). However, acrylic resin has a heat resistance of about 70°C.
It has the drawbacks of low impact resistance, low impact resistance, and easy warping due to moisture. In addition, in order to eliminate the above-mentioned drawbacks, the use of polycarbonate resin with a viscosity average molecular weight of 15,000 to 18,000 as a forming material for disks, lenses, etc. is being considered (Japanese Patent Laid-Open No. 58-180553).
However, it has drawbacks such as high birefringence, which is considered important, and there are limits to its use.

In an attempt to reduce birefringence, various methods have been proposed in which aromatic polycarbonate is modified or aromatic polycarbonate is mixed with other resins and used as a compound (for example, Japanese Patent Application Laid-Open No. 1983-1999) 19630, JP 61-19656, JP 62-18466
JP-A-62-20524, JP-A-61-
108617, JP 63-196612, JP 63-159415, JP 63-29
5662, JP-A-64-45433, and Functional Materials March 1987 p2i-29).

Although these proposals solve problems such as macroscopic light transmittance, new problems arise due to the fact that the composition of aromatic polycarbonate and polystyrene resin is itself an incompatible system. occurred, and the problem had not been essentially resolved. In other words, since it is an incompatible system, the phase dispersion in the structure tends to be coarse to some extent, and as a result, even in a system where the measured birefringence is reduced, individual differences in the submicron to micron size region This results in a difference in refractive index in the optical path, causing noise.

As described above, modified polycarbonate produced by conventional methods has fundamental defects and is not satisfactory in terms of properties when used as an optical material, particularly as a substrate for an optical disk.

[Problems to be Solved by the Invention] The present invention uses polystyrene resin as the backbone polymer, blends polycarbonate resin with a polystyrene copolymer grafted with a carbonate compound, and creates a transparent resin composition with high light transmittance and strength. The purpose of the present invention is to provide an optical material that has excellent optical properties, no phase separation, and low optical distortion. A further object of the present invention is to provide a polystyrene copolymer that can be used as a component of this optical material.

[Means for Solving the Problems] That is, the present invention has repeating units [I] and [II] represented by the general formula, and [
I]: The molar ratio of [n] is x:y, and y/(x+
y)=0.03 to 0.5.

[However, in the formula, m is an integer from 1 to 10, R1 is hydrogen, and has 1 to 1 carbon atoms.
12 alkyl group, phenyl group, cumyl group, phenoxy group, benzoyl group or. ] The styrenic copolymer of the present invention can be produced as follows.

As shown below, [SHMI] A costyrene-maleic anhydride copolymer is treated with aminophenol to obtain a styrene-hydroxyphenylmaleimide copolymer (SHMI), preferably a carbonate oligomer with n of 1 to 5 [I[] or [ IV] is grafted to form a graft copolymer. The copolymerization composition of the polystyrene copolymer is such that the repeating unit [I] derived from styrene and the repeating unit [II] derived from maleic acid are y/(x+y)=0.03 to 0. Make it 5.

If this is less than 0.03, the effect of improving compatibility is small, and 0.
．． When it exceeds 5, mechanical strength decreases.

In addition, the average value of the m values of the above repeating unit [■] is 20
If you try to obtain a polymer exceeding
is from 1 to 10. In order to prevent this gelation, it is preferable to use a molecular weight regulator when performing grafting using oligomers.

In the above copolymer synthesis reaction, the aminophenol treatment involves mixing the styrene/maleic anhydride copolymer with an aminophenol such as m-aminophenol or p-aminophenol in a solvent such as THF with a dehydrating agent such as acetic anhydride. The reaction is carried out by reacting for 0.5 to 20 hours at a temperature of 20 to 200 DEG C. in the presence of styrene-hydro-oxyphenylmaleimide copolymer (SHMI). Next, this is reacted with carbonate oligomer [1] or compound [IV] in a solvent such as methylene chloride, if necessary, in the presence of a molecular weight regulator such as bara-tertiary butylphenol. At this time, if a dihydric phenol such as bisphenol A is allowed to coexist, a polycarbonate homopolymer can also be synthesized at the same time.

The obtained copolymer has a weight average molecular weight of 50,000 to 3
00,000 and a glass transition temperature of 110 to 150°C is preferably used.

By blending the polystyrene copolymer of the present invention with a polycarbonate resin, it can be made into an optical material with excellent light transmittance and strength and low optical distortion. In this case, the resin composition is made up of 10 to 95% by weight of the polystyrene copolymer and 90 to 5% by weight of the polycarbonate resin.

When the polystyrene copolymer content is less than 10% by weight, optical distortion becomes large, and when it exceeds 95% by weight, mechanical strength decreases.

The polystyrene copolymer and the polycarbonate resin may be mixed together to form a composition by simultaneously synthesizing the polycarbonate resin when synthesizing the polystyrene copolymer, or the resins synthesized separately may be combined. In this case, it is preferable to perform the mixing while dissolving the components in a solvent.

As polycarbonate resin, bisphenol A etc.
A material with excellent transparency and strength that is manufactured by a solution method, a melting method, etc. using hydric phenol as a raw material is used.

[Examples] The present invention will be described below based on Examples, but the present invention is not limited thereto.

Example 1 Styrene/maleic anhydride (14 mol%) copolymer [molecular weight (measured by GPC) Mw = 170,000] 10
0 g was dissolved in 1000 ml of tetrahydrofuran (THF), 16 g of m-aminophenol was added, and the mixture was reacted at room temperature for 4 hours with stirring. After the reaction is complete, 5I! of methanol to obtain a white polymer.

30 g of the polymer were dissolved in 600 ml of a methylene chloride solution containing a bisphenol A skeleton polycarbonate oligomer with roloformate end groups at a concentration of 220 g/l, and 8.0 g of paratertiary butylphenol was added as a molecular weight regulator. 0g1 Bisphenol A
2N aqueous sodium hydroxide solution containing 16.2g dissolved in 200Trf! , 1 mL of 0.01 N triethylamine aqueous solution was added thereto, and the mixture was reacted for 1 hour with vigorous stirring. After the reaction, it was diluted with 1.51 g of methylene chloride, water and 0.5 g of diluted with methylene chloride.
The solution was washed with normal hydrochloric acid and water in this order. This solution was poured into 51 methanol to obtain a white polymer. This was washed with acetone-methanol and then dried.

The molecular weight of the polymer (measured by GPC) is Mw=12
7,000 (polystyrene equivalent). When the styrene-maleimide part was fractionated by GPC and subjected to NMR measurement, it was confirmed that the styrene-maleimide part had the following repeating units in the following proportions. Further, according to NMR measurement, the ratio of polycarbonate part/styrene-maleimide part was 70/30.

Moreover, the molecular weight of the polycarbonate homopolymer produced during the polymerization was Mw=9.soo.

The polymer was molded to a thickness of 1 mm using a minimat molding machine manufactured by Sumitomo Heavy Industries.
．． It was shaped into a 2mm, 4cm square plate. The light transmittance (830 nm) of this precept-shaped article was 89%. Also, 30
'The difference between the birefringence of obliquely incident light and the birefringence of vertically incident light is 20n.
It was m. The normal incidence birefringence was about ±20 nm.

Example 2 50 g of a polymer treated with aminophenol in the same manner as in Example 1 except that a styrene/maleic anhydride (7 mol %) copolymer [molecular weight (GPC) Mw = 120,000] was used.
was dissolved in 500 inches of methylene chloride, and 220 g/polycarbonate oligomer having chloroformate end groups was dissolved in 500 inches of methylene chloride.
250 ml of a methylene chloride solution containing 1 ml of methylene chloride solution and 10.2 g of baratatcial butylphenol were added, and pyridine was added dropwise with stirring, followed by reaction for 1 hour. After the reaction, the reaction was stopped with a small amount of water, and the polymer was precipitated with methanol, washed with acetone-methanol, and then dried. The molecular weight of this polymer was Mw=15, SOO (polystyrene equivalent). Moreover, the glass transition temperature of this polymer was 124°C.

30 g of the polymer and polycarbonate (viscosity average molecule j
1Mv=15,000) was dissolved in methylene chloride and blended. After precipitation in methanol, dry
Melt pressed. The glass transition temperature of the sample is 134℃
, and no other peaks were observed.

The blended polymer was molded to a thickness of 1.5 mm using a Sumitomo Heavy Industries mini mat molding machine. A 2 mm square, 4 cm square plate was cut out. The light transmittance (830 nm) of this molded article was 89%. The birefringence of vertical human light at the center of this molded product is +30
nm, and the refraction of 30'' incident light was +80 nm.

Example 3 100 g of styrene/maleic anhydride (7 mol%) copolymer [molecular weight (measured by GPC) Mw = 120,000] was dissolved in 1000 Tn1 of tetrahydrofuran (THF), and 7.8 g of m-aminophenol was added. and reacted at room temperature for 4 hours. To this reaction mixture, pyridine 30Tn1,
30'ml of acetic anhydride was added and reacted at room temperature for 4 hours.

The reaction solution was poured into 51 methanol and white styrene/
A m-hydroxyphenylmaleimide copolymer was obtained.

The styrene/m-hydroxyphenylmaleimide copolymer obtained above was dissolved in methylene chloride 1000711i1', 10.4 g of phenylchloroforme was added, and pyridine iom was added with stirring. After reacting for 2 hours after addition, the mixture was precipitated with methanol (51) and washed several times with methanol to obtain a polymer having the structure shown below.

The polymer had a Tg of 120°C and a molecular weight (measured by GPC) of Mw=120,000. From NMR measurement, it was confirmed that the following repeating units were contained in the following proportions.

50 g of this polymer and 50 g of polycarbonate (viscosity average molecular weight (Mv) = 15,000STg 145°C)
After dissolving the polymer in methylene chloride, the polymer was recovered with methanol and dried under reduced pressure at 100°C. After melt molding the polymer mixture, differential scanning calorimetry (D
When the glass transition point was measured by SC), only one peak appeared, and the Tg was 134°C. Further, the flexure polymer was coated with a Sumitomo Heavy Industries Minimat to a thickness of 1.
A flat plate of 2 mm and 4 cm square was molded. The light transmittance (830 nm) of this molded article was 89%. Also, 30'
The difference between the birefringence of obliquely incident light and the birefringence of vertically incident light is 50
It was nm.

Example 4 Styrene/maleic anhydride (7 mol%) copolymer of Example 3 [Molecular fi (measured by GPC) MW=120,000]
A styrene/m-hydroxyphenylmaleimide copolymer was obtained in the same manner as in Example 3 except that a styrene/maleic anhydride (14 mol %) copolymer was used instead.

This polymer had a Tg of 132°C and an Mw of 170,000.

30 g of this polymer and 70 g of polycarbonate were mixed according to Example 1, and the following measurements were performed.

The glass transition temperature determined by DSC was 142°C, and there was one peak. The light transmittance of the flat plate was 90%, and the difference in birefringence was 30 nm.

Comparative Example 1 Polycarbonate (Mv=15,000) with a thickness of 1.2
It was cut into a flat plate of 4 cm square. Light transmittance (830
nm) was 89%. The birefringence of normal incident light is +40
The birefringence of the incident light was +170 nm.

Comparative Example 2 The same procedure as Comparative Example was carried out except that a styrene/maleic anhydride (7 mol %) copolymer [molecular weight (measured by GPC) Mw=120,000] was used. Light transmittance (830nm) is 88
%Met. The normal incidence birefringence was -420 nm, and the 30° incidence birefringence was -490 nm.

Comparative Example 3 The polymers of Comparative Examples 1 and 2 were blended and molded. The molded product was cloudy.

[Effects of the Invention] The resin composition of the present invention, which uses the polystyrene resin as a backbone polymer and blends a polycarbonate resin with a polystyrene copolymer grafted with a carbonate compound, is a transparent resin composition with excellent light transmittance and strength. It is an optical material with no phase separation and small optical distortion, and its industrial value is extremely large.

Furthermore, according to the present invention, a polystyrene copolymer that can be used as a component for optical materials could be obtained.

Claims (1)

[Claims] 1. Repeating units [I] and [II] represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[II] has [
I]:[II], the molar ratio is x:y, y/(x+y)
=0.03 to 0.5 polystyrene copolymer. [However, in the formula, Z is ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, m is an integer from 1 to 10, and R^1 is hydrogen, the number of carbon atoms 1
There are ~12 alkyl groups, phenyl groups, cumyl groups, phenoxy groups, benzoyl groups, or ▲numerical formulas, chemical formulas, tables, etc.▼ (R^2 is an alkyl group with 1 to 4 carbon atoms). ] 2. Polystyrene copolymer 10 to 95 according to claim 1
A resin composition comprising 90 to 5% by weight of polycarbonate resin.