JPH01110556A - Polycarbonate based resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition having excellent transparency and capable of providing a molded product having small optical strain, by blending polystyrene with an aromatic polycarbonate copolymer led from a bisphenol component having 2 or 3 kind of different structures. CONSTITUTION:(A) 1-99wt.% aromatic polycarbonate copolymer obtained by subjecting (A1) a mol.% 2,2-bis-(4-hydroxyphenyl)propane to carbonate bonding with (A2) b mol.% 1,1'-bis-(4-hydroxyphenyl)-P-diisopropylbenzene and (A3) c mol.% 1,1-bis-(4-hydroxyphenyl)-cyclohexane by ester exchange method at a ratio satisfying formula I - formula VI and having preferably 3,000-50,000 viscosity-average molecular weight is blended with (B) 99-1wt.% preferably 3-60wt.% styrene homopolymer having preferably 10,000-200,000 number- average molecular weight.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an excellent transparent polycarbonate copolymer derived from bisphenol components having two or three different structures, which is blended with a polystyrene resin. The present invention relates to a polycarbonate resin composition having properties. especially,
Specifically, the present invention relates to a composition that provides a molded article with excellent transparency and low optical distortion.

(Prior Art and its Problems) There is no disclosure yet of a composition that can maintain transparency over the entire mixing ratio range of mixing a polycarbonate resin and a styrene homopolymer. In Japanese Patent Publication No. 43-6295, polycarbonate resin and polystyrene are mixed,
Reports have been published that provide polycarbonate resins that maintain transparency and have a high softening point. However, as shown in the above notice, when mixing polystyrene, the transparency of the molded product gradually decreases as the amount of polystyrene mixed increases, and when the amount of additive exceeds 30%, it becomes cloudy. becomes large, and it is impossible to provide a transparent resin over the entire composition range in the mixture.

On the other hand, molding materials used in the production of molded articles for optical devices are often required to have excellent transparency and particularly low optical distortion. However, there are very few plastic molding materials that can satisfactorily satisfy these conditions.

In recent years, optical information recording substrates have attracted attention as optical materials. In other words, Direct Read After Write (DRAW) is a method in which a spot beam of a laser beam is applied to a disk to record signals on the disk in minute pits, and the signals recorded by the pits are read out by detecting the amount of reflected or transmitted light from the laser beam. , Erasable Direct Read After Write (EDR)
AW) type optical information recording and reproducing system is attracting attention.

Disks used in such recording and reproducing systems are required not only to be transparent because a laser beam passes through the disk body, but also to have optical homogeneity to reduce reading errors. Thermal stress, molecular orientation, and
Birefringence occurs when the laser beam passes through the disk body, mainly due to residual stress due to volume changes near the glass transition point. This large optical non-uniformity caused by birefringence is a fatal defect for optical discs.

In general, polymethyl methacrylate (hereinafter abbreviated as PMMA) is a typical plastic material that has outstanding transparency and weather resistance, low birefringence, good moldability, and balanced mechanical strength. It is known that it can be used as an optical material.

However, PMMA has relatively high water absorption and is not suitable for applications requiring highly precise dimensional stability.

Further, bisphenol A homopolycarbonate (hereinafter abbreviated as PC) is a type of engineering plastic that has transparency comparable to that of PMMA, has excellent heat resistance and impact resistance, and has low water absorption.

However, PC has a phenyl ring which is a functional group with large optical anisotropy, tends to cause birefringence, and has poor moldability.

On the other hand, even if PC is used, the molding temperature must be increased, or
Birefringence can be reduced by lowering the average molecular weight of the resin and lowering its melt viscosity, but an increase in molding temperature causes thermal decomposition of the resin, and a decrease in molecular weight causes a decrease in mechanical strength. Each has its limits.

Under these circumstances, many proposals have been made for reducing birefringence in PCs for optical disks.

For example, ■ improving the fluidity of PC in order to reduce orientational birefringence (JP-A-58-126119; JP-A-6
0-215051. Japanese Patent Publication No. 61-16962. Tokukai Showa 6
1-78864, 4? Kaisho 6l-123658) ■ Dihydric phenol having a skeleton other than bisphenol A, or
Decreasing the photoelastic constant using an aliphatic alcohol (JP-A-60-83239; JP-A-60-16321.
JP-A-60-166322, JP-A-61-55116.
Japanese Patent Publication No. 61-55117. Japanese Patent Publication No. 61-223025.
Japanese Patent Publication No. 62-2770. JP-A No. 62-3443゜ JP-A No. 62-39624) ■ Introducing a polyester carbonate or polyether carbonate structure into PC to lower the photoelastic constant and improve fluidity. (Unexamined Japanese Patent Publication No. 6
0-188422, JP-A-60゜188426, JP-A-62-36457) However, in these proposals, since the birefringence is caused by the chemical structure of PC itself, it is difficult to stabilize a substrate with low birefringence. The situation is such that it is difficult to manufacture these products.

Furthermore, the birefringence canceling effect of polymer blends has recently been proposed. [U.S. Pat. No. 4,373,065. polymer(
Polymer); vol. 26, p. 1619 (1985 edition), JP-A-61-108617] These basic principles are as follows. In other words, the principle is that if a polymer with positive birefringence and a polymer with negative birefringence are made compatible, positive and negative birefringence can be canceled out without losing transparency, and a molded or stretched product without birefringence can be obtained. Based on. PC
Examples of materials that eliminate the inherent birefringence of N-phenylmaleimide and N-phenylmaleimide include phenylmaleimide, styrene copolymer, maleic anhydride-styrene copolymer (Japanese Patent Application Laid-Open No. 61-19656).

Examples include a terpolymer of t-butylmaleimide and styrene (Japanese Patent Application Laid-open No. 18466/1983).

(Means for Solving the Problems) The present invention relates to a mixed system of an aromatic polycarbonate copolymer and a polystyrene resin, and has found a polycarbonate resin composition that can maintain excellent transparency in the entire mixing ratio range. More specifically, the present invention was achieved by discovering a molded product with excellent transparency and low optical distortion.

That is, the present invention comprises (1) (a) 1 to 99% by weight of an aromatic polycarbonate copolymer using several specific dihydric phenol compounds, and (b) 99 to 1% by weight of a styrene homopolymer. (2) An aromatic polycarbonate copolymer prepared using several specific dihydric phenol compounds is 2,2-bis-(
4-hydroxyphenyl)propane (i) a mol% and 1
, 1-bis-(4-hydroxyphenyl)-p-diisopropylbenzene (ii)b mol% and 1,1-bis-(
4-hydroxyphenyl)cyclohexane(iii)c
The polycarbonate resin composition according to (1) above, which is an aromatic polycarbonate copolymer obtained by carbonate bonding of mol %.

Here, a, b, and c (mol%) used in the resin composition range of the aromatic polycarbonate copolymer are represented by the following formula (I) ~
This is an aromatic polycarbonate copolymer that satisfies (VI).

a+b+c=100 -...CI)0≦b<
100 (II) 0≦c≦7
5 ・---...(IH)O≦a≦35+
5.5c However, when O≦c≦10... (■) 0≦
a≦100-c However, when 10≦c≦70... (
V) 0≦a≦450-6c, but when 70≦c≦75・
...(■) Each constituent unit (i X ii
If iii) is outside the above range, the polycarbonate resin composition obtained by mixing with the styrene homopolymer will lose its transparency.

The copolymer of the present invention has a viscosity average molecular weight of 13.000 to 50.0 in terms of bisphenol A-polycarbonate.
00 is preferred. If it is less than 13,000, the copolymer will become brittle, and if it exceeds 50,000, it will be difficult to provide a molding material with small optical distortion.

In addition, the styrene homopolymer used for mixing with the above-mentioned aromatic polycarbonate copolymer may contain 3 to 6 % of the styrene homopolymer in the composition.
It is particularly desirable that the content be in the range of 0% by weight.

That is, if it is less than 3% by weight, it will be difficult to maintain optical homogeneity, and if it exceeds 60% by weight, it will cause problems such as a decrease in the coloring and mechanical properties of the molded product due to a decrease in thermal stability.

The above-mentioned styrene homopolymer preferably has a number average molecular weight between 10,000 and 200,000, and if it is outside this range, either mechanical properties or optical homogeneity may be affected. occurs.

There are the following two methods for producing the aromatic polycarbonate copolymer of the present invention.

■Transesterification method 2.2-His-(4-hydroxyphenyl)propane, 1.1-bis-(4-hydroxyphenyl)-1)-
diisopropylbenzene and 1,1. Diphenyl carbonate in a slight excess of the stoichiometric equivalent to the compound of bis(4-hydroxyphenyl)cyclohexane,
In the presence of a conventional carbonation catalyst, about 160-180
Approximately 3 °C under normal pressure and with inert gas introduced.
React for 0 minutes, then gradually reduce the pressure over 2 hours for about 18 minutes.
Finally 10 Torr under the temperature of 0-220 °C, 2
Precondensation is completed at 20°C. After that, 10 Torr,
30 minutes at 270°C, 5 Torr, 2 at 270°C
0 minutes, then 270'C under reduced pressure of 0.5 Torr or less, preferably 0.3 Torr-0,ITorr.
After 1.5 to 2.0 hours, proceed with the condensation.

In addition, carbonation catalysts for carbonate bonding include alkali metals such as lithium-based catalysts, potassium-based catalysts, sodium-based catalysts, calcium-based catalysts, and tin-based catalysts;
Alkaline earth metal catalysts are suitable, such as lithium hydroxide, lithium carbonate, potassium borohydride, potassium hydrogen phosphate, sodium hydroxide, sodium borohydride, calcium hydride, dibutyltin oxide.

Examples include stannous oxide. Among these, it is preferable to use a potassium catalyst.

■Phosgene method Attach a stirrer, a thermometer, a gas inlet pipe, and an exhaust pipe to a three-bottle flask and add 2,2-bis-(4-hydroxyphenyl)propane and 1,1'-bis-(4-hydroxyphenyl). -1)-diisopropylbenzene and 1,
A pyridine solution of a mixture of 1-bis(4-hydroxyphenyl)cyclohexane is added, and phosgene gas is introduced while stirring the mixture vigorously. Since phosgene is extremely poisonous, it must be operated in a strong fume hood. Additionally, a unit is attached to the exhaust terminal that decomposes and detoxifies excess phosgene with a 10% aqueous sodium hydroxide solution. For phosgene, use the empty air washing bottle from the cylinder.

Introduce the paraffin into the flask through an air washing bottle (count the foam) and an empty air washing bottle. The gas introduction tube should be inserted above the stirrer, and the tip should be widened into a funnel shape to prevent it from becoming clogged by precipitated pyridine salt.

As gas is introduced, pyridine hydrochloride precipitates and the contents become cloudy. Water cooling is performed so that the reaction temperature is 308C or less. It becomes viscous as the condensation progresses. Phosgene
Pass phosgene through until the yellow color of the hydrogen chloride complex no longer disappears. After the reaction is completed, methanol is added to precipitate the polymer, which is then filtered and dried. Since the polycarbonate produced is soluble in methylene chloride, pyridine, chloroform, tetrahydrofuran, etc., it is purified by reprecipitation from these solutions with methanol.

The above-mentioned aromatic polycarbonate copolymer and styrene resin can be uniformly mixed using a known melt mixing method using an extruder, kneader, Banbury mixer, etc., or by dissolving them in a common solvent such as methylene chloride and mixing with the solvent. , a post-drying method, etc.

Further, the resin composition according to the present invention may contain, if necessary, a known lubricant and various stabilizers within a range that does not harm the physical properties of the product.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples. In addition, the viscosity average molecular weight shown in the following reference examples and examples is
Bisphenol A, the intrinsic viscosity [11
1 and the viscosity average molecular weight Mv [! 11: 1.11 x 10-4 (Mv) 0.8
This is the molecular weight of bisphenol A in terms of polycarbonate calculated from the intrinsic viscosity using the formula of 2 [E, Miiller and C, Bayer; US Pat. No. 2,999,844].

(Reference Examples and Examples) Reference Example 1 Synthesis of aromatic polycarbonate copolymer (ester exchange method) 2. 14 parts by weight (5 mo 1%) of 2-his-(4-hydroxyphenyl)propane and 1,1'-bis -(4-hydroxyphenyl)-p-diisopropylbenzene 24
5 parts by weight (59 mo1%) and 116 parts by weight (36 mo1%) of 1,1-bis-(4-hydroxyphenyl)cyclohexane.
1%) and 264 parts by weight of diphenyl carbonate.
The mixture was placed in a three-necked flask, and after repeating degassing and N2 purging five times, it was melted in a silicon bath at 180°C while nitrogen was introduced. Once melted, add a solution of potassium borohydride, the carbonation catalyst, dissolved in phenol (
3 x 10-3 for the total amount of bisphenol charged
Mo1% amount) was added, and the mixture was stirred and incubated at 180°C under N2 for 30 minutes. Next, the pressure was reduced to 100 Torr at the same temperature,
After stirring for 30 minutes, the pressure was further reduced to 50 Torr at the same temperature, and the mixture was reacted for 30 minutes. Then gradually increase the temperature to 220°C
The reaction was carried out for 30 minutes, and 80% of the theoretical amount of phenol was distilled out through the reaction up to this point.

Thereafter, the pressure was reduced to 10 Torr at the same temperature, and the reaction was carried out for 30 minutes, and the temperature was gradually raised to 270°C, and the reaction was carried out for 30 minutes. Further, at the same temperature, the pressure was reduced to 5 Torr and the reaction was allowed to proceed for 30 minutes, and almost the entire theoretical amount of phenol was distilled off, completing the precondensation.

Next, the edges were aligned at the same temperature for 2 hours at 0.1 to 0.3 Torr. After the product polymer was taken out and cooled under nitrogen, the solution viscosity was measured at 200C using dichloromethane as a solvent. The viscosity average molecular weight (hereinafter abbreviated as Mv) calculated from this value was Mv=16,520. The refractive index (hereinafter abbreviated as n) measured using an Atsube refractometer was nD=1.5922. Also,
Differential scanning calorimeter (DSC; Perkin -
Elmer 2C type), the glass transition temperature (hereinafter abbreviated as Tg) was found to be Tg = 156°C. In addition, the water absorption rate (hereinafter abbreviated as Wab) measured according to ASTM-D-570-63 is Wab = 0
．． It was 23%. Furthermore, the photoelastic constant (hereinafter abbreviated as C) is C=32 Brewsters
, 10-12 m2/N). The photoelastic constant was measured using a self-made one, but the method for calculating the photoelastic constant was to add different magnitudes of tensile stress to the test piece (100mm x 10mm x 1mm) in the length direction, and to calculate each using the following formula (1). The photoelastic constant was determined from the slope by substituting the value.

nl-n2=c(al-(72)) (1) However, nl-n2: Birefringence σ1-02: Residual stress C: Photoelastic constant Reference example 2 Synthesis of aromatic polycarbonate copolymer (phosgene method) Three Attach a stirrer, a thermometer, a gas inlet pipe, and an exhaust pipe to the flask.
55 parts by weight (20 mo1%) of 2-bis-(4-hydroxyphenyl)propane, 179 parts by weight (43 mo1%) of 1,1'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene, and 1,1-bis-(4-hydroxyphenyl)-p-diisopropylbenzene. -(4-hydroxyphenyl)cyclohexane 119 parts by weight (37 mo1
%) was dissolved, dichloromethane was added, and phosgene gas was introduced while stirring vigorously. Phosgene was introduced from the cylinder into the flask through an empty washing bottle, a washing bottle filled with water, and an empty washing bottle. The reaction temperature during the introduction of phosgene gas was water-cooled to 25°C or less. As the condensation progresses, the solution becomes viscous. Further phosgene was passed through the mixture until the yellow color of the phosgene-hydrogen chloride complex no longer disappeared.

After the reaction is complete, pour the reaction solution into methanol and filter it.
Repeated washing. Furthermore, the polycarbonate produced is
It was purified by reprecipitation with methanol from a dichloromethane solution.

After purification and thorough drying, the solution viscosity was measured at 20°C using dichloromethane as a solvent. The viscosity average molecular weight Mv calculated from this value was 18,420. Furthermore, the same measurements as in Reference Example 1 were performed, and the results of the refractive index, glass transition temperature, photoelastic constant, and water absorption rate were shown in Table 1.

Reference Examples 3 to 5 Bisphenol (II) (II) (III) was prepared in Reference Example 1 or Reference Example 2 in the proportions listed in Table 1, respectively.
A copolymer was synthesized by the polycarbonate copolymer manufacturing method (ester exchange method or phosgene method) shown in . The properties of these resins were measured in the same manner as Reference Example 1 and Reference Example 2, and the results are shown in Table 1.

Incidentally, Table 1 also lists the initial characteristics of Reference Examples 6 and 7 described below.

Reference example 6 Bisphenol A homopolycarbonate AD5503 (
Ondai Kasei Co., Ltd. (trade name) is a bisphenol A homopolycarbonate whose viscosity average molecular weight, calculated from the solution viscosity measured at 20°C using dichloromethane as a solvent, is Mv = 17,000. . Also, AD55
In 03, the number average molecular weight according to G and Pρ is 11,0
00 and the weight average molecular weight is 37,000.

Reference Example 7 Styrene homopolymer 5tyron666 (trade name of Asahi Kasei Co., Ltd.) is G,
It is a styrene homopolymer with a number average molecular weight of 55,000.

(Examples 1 to 7 and Comparative Examples 1 and 2) The aromatic polycarbonate copolymers of Reference Examples 1 to 5 above are respectively abbreviated as polycarbonate resin-V, and the bisphenol A-homopolycarbonate obtained in Reference Example 6 is It is abbreviated as polycarbonate resin ■. Furthermore, reference example 7
The homopolystyrene obtained is abbreviated as styrenic resin A.

Polycarbonate resin ~■ and styrene resin A are the second
The mixture was kneaded using a 20Φ Brabender Extruder in the proportions shown in the table and pelletized to obtain a polycarbonate resin composition.

When various properties were measured for each of the obtained polycarbonate resin compositions, the results shown in Table 2 were obtained.

(Effects) As is clear from the results in Table 2, the polycarbonate resin composition according to the present invention is a resin composition with excellent transparency and small optical distortion.

It is also used in engineering plastics, particularly in fields where transparency is required.

Claims (2)

[Claims] (1) (a) A mixture of 1 to 99% by weight of an aromatic polycarbonate copolymer using several specific dihydric phenol compounds and (b) 99 to 1% by weight of a styrene homopolymer. Transparent polycarbonate resin composition (2) Aromatic polycarbonate copolymers made using several specific dihydric phenol compounds are 2,2-bis-(
4-hydroxyphenyl)propane (a mol%) and 1,
1'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene (b mol%) and 1,1-bis-(4-
2. The polycarbonate resin composition according to claim 1, which is an aromatic polycarbonate copolymer obtained by carbonate-bonding hydroxyphenyl)cyclohexane (c mol %). Here, a, b, c (mol%) used for the resin composition range of the aromatic polycarbonate copolymer are expressed by the following formula (I)
It is an aromatic polycarbonate copolymer that satisfies (VI). a+b+c=100...(I) 0≦b<100...(II) 0≦c≦75...(III) 0≦a≦35+5.5c However, 0≦ When c≦10...
...(IV) 0≦a≦100-c, but when 10≦c≦70...
・(V) 0≦a≦450-6c However, when 70≦c≦75...
...(VI)