JPS63122729A - Polycarbonate resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin, containing a polymer having an alicyclic diol linked through carbonate bonds and capable of providing molded articles having excellent transparency, well sustained moisture and heat resistance with hardly any optical stress. CONSTITUTION:A polycarbonate resin containing a polymer obtained by linking an alicyclic diol through carbonate bonds. Norbornanediol which is an organic alicyclic compound is used as the alicyclic diol. The resin is used by molding into substrates for optical disks. The above-mentioned polymer is produced by ester interchange reaction of the alicyclic diol with diphenyl carbonate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel carbonate resin, and particularly to a polycarbonate molding material that has excellent transparency and low optical distortion.

The present invention is particularly applicable to substrate materials for high-density information recording media such as optical disks and optical cards, structural materials for optoelectronic elements such as optical circuits and optical modulators, and display components, and molding materials for optical components such as functional materials. This relates to polycarbonate resins that can be produced.

(Background of the Invention) Conventionally, acrylic resins such as polymethyl methacrylate and polycarbonate resins have been used as molding materials for plastic optical molded products.

However, such conventional plastic-based optical molded products have the following drawbacks. That is, polymethyl methacrylate has disadvantages in moisture resistance, poor dimensional stability, and tends to cause cracking, and also has a low glass transition temperature and unsatisfactory heat resistance. Although polycarbonate has excellent moisture resistance and heat resistance, it inherently has a large birefringence, and there is a problem in that the birefringence is large due to molding distortion.

When moisture resistance and low birefringence are required, such as optical disks and optical cards, especially magneto-optical recording disks, it is preferable to use polycarbonate as the disk substrate material. In order to make such substrates, the molding conditions are extremely strict, and there is a strong demand for improvements in the polycarbonate resin itself.

(Prior Art) In order to improve polycarbonate for optical applications, it has been proposed to add terminal stoppers and branching agents to conventional polycarbonate, or to blend it with other polymers ( For example, see JP-A No. 60-215019, JP-A No. 60-215020, and JP-A No. 61-19656), but since there is no major change in the basic structural unit of polycarbonate, its optical properties are improved. It is also very small.

(Objective of the Invention) The object of the present invention is to improve optical properties while maintaining moisture resistance and heat resistance by changing the basic structural unit of polycarbonate.
In particular, it is an object of the present invention to provide a polycarbonate resin with significantly reduced birefringence.

(Structure of the Invention) The polycargonate resin for molding optical parts provided by the present invention is characterized by containing a polymer obtained by carzenate bonding of alicyclic diol.

The above-mentioned alicyclic diol includes cyclobutanediol,
Cyclo-tetanediol, cyclobutanediol, cyclohexane dimetatool, cyclohexanejetanol, 2,2-bis(4-hydroxycyclohexyl)f-ropane, 2,4'-dihydroxydicyclohexyl-methane, bis(2-hydroxycyclohexyl) ) methane, bis-(4-hydroxycyclohexyl)methane, bis-
(4-Hydroxy-2,6-dimethyl-3-methoxycyclohexyl)methane, 1,1-bis-(4-hydroxycyclohexyl)-ethane, 1,2-bis-(4-hydroxycyclohexyl)-ethane, (bicyclohexyl) ) -4,4'-diol and these alkyl substituted products.

The above polymers of the present invention can be made using the transesterification method or the phosgene method. In the transesterification method, the above diol may be reacted with, for example, diphenyl carbonate. In the phosdan method, the diol and phosdan are reacted in an aqueous sodium hydroxide solution in the presence of methylene chloride and a tertiary amine catalyst using an interfacial polymerization method.

It is also possible to synthesize the dichloroformate of the above-mentioned diol in advance and react it with other diol compounds, which is particularly used in the synthesis of copolycondensates.

Some of the above diols of the present invention can be substituted with dihydric phenols. Regarding dihydric phenols that can be used,
Particular examples include, but are not limited to: 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)propane, -hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 1
,1-bis(4-hydroxyphenyl)cyclohexey
Examples include.

Further, as the alicyclic diol, a norbornane diol of a bridged alicyclic compound, for example, bis(hydroxymethyl) norbornane or dihydroxynorbornane can be used.

Since the polycarbonate resin of the present invention has an alicyclic structure, the molecular chain is not flexible and the movement of the molecular chain is restricted, so it has good heat resistance like aromatic polycarbonate. Moreover, it has an alicyclic structure that does not contain π electrons, and has less polarization and reduced birefringence than aromatic polycarbonate.

Furthermore, it has no crystallinity, is amorphous, has good transparency, and has excellent moldability.

The molding method is usually injection molding, compression molding, or the like, and in the case of injection molding, the resin temperature is 300-350°C.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Parts in the examples are by weight.

In addition, various physical properties obtained in the examples were measured by the following test methods.

(Photoelastic Constant) The principal refractive index difference is expressed as the product of the photoelastic constant and residual stress as shown in the following equation.

(η1-ηz)=C(σ1-σ2) However, (ηl-η2): Principal refractive index difference, (σl-σ2)
: principal stress difference, C: photoelastic constant Stress was applied to the test piece at room temperature, the principal refractive index difference was measured, and the photoelastic constant was determined using the above formula based on its slope.

(Light transmittance) Based on ASTM D-1003, the light transmittance was measured using a test piece having a thickness of 1 mm using a light transmittance measuring device.

(Example 1) 312 parts of a mixture of 2.5- and 2,6-bis(hydroxymethyl)norbornane, 4 parts of diphenyl carbonate
27 parts and 200.07 parts of L 10H-H were heated to 215°C under a nitrogen stream. As the phenol was eluted out of the system, the reaction temperature was cleaved for about 1 hour and gradually increased to 260°C. Next, the temperature was increased from 260°C to 270°C in about 10 minutes at 0.6-1.5 mmHg under reduced pressure,
The reaction continued for an additional 50 minutes at a temperature of 270°C.

The obtained norbornane polycarbonate had an intrinsic viscosity of 0.13 (chloroform solution, 25° C.).

This resin was processed in a vented 4 Q mm extruder at 250-3
It was extruded and pellet-molded at a temperature of 00°C. Next, heat press the obtained transparent resin at 240°C for 5 minutes,
A test piece was prepared and its properties were measured and shown in Table 1.

(Example 2) 2.2,4.4-tetramethylcyclobutane-1,3-
80 parts of dichloroformate of diol, 7 parts of 2,5- and 2,6-dihydroxynorbornane mixture, 2,
35 parts of 2,4.4-tetramethylcyclobutane-1,3-diol and 600 parts of toluene were reacted with stirring under reflux under a nitrogen stream for 5 minutes, and finally at 95°C.
It was cooled to

Next, a mixed solution of 300 parts of toluene and 500 parts of pyridine was added dropwise for about 10 minutes. Methanol is added to the resulting highly viscous colorless solution to precipitate the polymer,
The polymer was washed with methanol and finally with water. The resulting copolymerized polycarbonate had an intrinsic viscosity of 0.83 (chloroform solution, 25°C).

Table 1 shows the results of measuring the properties of the test pieces that were molded and hot pressed in the same manner as in Example 1.

(Example 3) In the same manner as in Example 2, dichloroformate of 2,2-bis(4-hydroxycyclohexyl)-propane 20
and 65 parts of 2,5- and 2,6:dihydroxynorbornane mixture, 80 parts of chlorobenzene and 80 parts of pyridine.
part of the mixed solution was added dropwise.

As in Example 2, the reaction mixture was allowed to react under reflux for about 10 minutes.

The obtained copolycondensation polycarbonate has an intrinsic viscosity of i, s
(Chloroform solution, 25°C).

Table 1 shows the results of measuring the properties of the test pieces that were molded and hot pressed in the same manner as in Example 1.

(Comparative Example 1) Aromatic polycarbonate (manufactured by Teijin Kasei Ltd., Nokunrai AD5503) was hot pressed in the same manner as in Example 1 to create a test piece, and the properties were measured. The results are shown in Table 1. .

(Effects of the Invention) As shown in Table 1, the polycarbonate resin optical molded product of the present invention has good transparency, a small photoelastic constant,
Therefore, it has less optical distortion and is superior to conventional aromatic polycarbonate resin optical molded products.

Table 1

Claims (3)

[Claims] (1) A polycarbonate resin for molding optical parts, comprising a polymer obtained by carbonate bonding an alicyclic diol. (2) The polycarbonate resin according to claim 1, wherein the alicyclic diol is a norbornane diol of a bridged alicyclic compound. (3) The polycarbonate resin according to claim 1 or 2, wherein the optical component is a substrate for an optical disc.