JPS6392644A - Polycarbonate resin - Google Patents

Abstract

PURPOSE:To provide a polycarbonate resin having excellent transparency and resistance to moisture and heat and exhibiting low optical distortion, having a specified cyclobutane unit in its molecular structure. CONSTITUTION:A diol having a cyclobutane unit (e.g., 2,4-di methylcyclobutanediol-1,3) and diphenyl carbonate are subjected to an ester exchange reaction to obtain a polycarbonate resin having a substd. cyclobutane unit of the formula (wherein A1, A2, A3 and A4 are each H or a 1-4C aliph. hydrocarbon).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a new polycarbonate 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 reactions, 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 also 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 storage disks, it is preferable to use polycarbonate as the disk substrate material; In order to make a substrate of 4'20 nm or less, the molding conditions are extremely strict, and there is a strong demand for improvement of the polycarbonate resin itself.

(Prior art) In order to improve polycarpinate for optical applications, it has been proposed to add end-stopping agents and branching agents to conventional 721J carpinate, or to blend it with other polymers. (For example, JP-A No. 60-215019, JP-A No. 60-215020, JP-A-61-1965)
(see No. 6), but since there is no major change in the basic structural unit of polycarbonate, the improvement in its optical properties is slight.

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

(Structure of the Invention) The polycarbonate resin provided by the present invention has a cyclobutane unit represented by the general formula: (where A1. A2. A3. A4 represents a hydrogen atom or an aliphatic hydrocarbon having 1 to 4 carbon atoms). It is characterized by its inclusion in the molecule.

Examples of the cyclobutane unit include 2,4-nomethylcyclobutane, 2 + 2 + 4 + 4-tetramethylcyclobutane, 2,4-noethylcyclobutane, and preferably 2,2.4.4- Tetramethylcyclobutane.

The above cyclobutane unit can be incorporated into the polycarbonate skeleton by using it in the form of a diol compound during polycondensation of the polycarbonate.

That is, the above diol compound and nophenyl car? It can be produced using a transesterification reaction with ester, or by a phosgene method in which the diol compound and phosdan are subjected to interfacial polymerization in an aqueous sodium hydroxide solution in the presence of a tertiary amine while adding methylene chloride. The diol compound in this case is the diol of the cyclobutane unit, that is, 2,4-dimethylcyclobutanediol-1,3,2,2,4,4-tetramethylcyclobutanediol-1,3,2,4-diethylcyclobutane. Examples include diol-1, 3, etc. Especially 2,2,4.4-
Tetramethylcyclobutanediol-1,3 is preferred. These may be cis- or trans isomers alone or in mixtures.

In the present invention, a part of the above diol compound can be replaced with a common dihydric phenol. This dihydric phenol is the one used in ordinary polycarbonate,
For example, 2,2-bis(4-hydroxyphenyl)furonogun (hereinafter referred to as bisphenol A, !: abbreviated f), bis(4-hydroxyphenyl),
-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cy/l lohexene, etc. can give.

Therefore, the polycarbonate resin according to the present invention has the general formula: (where A1.A2.A3.A4 is a hydrogen atom or an aliphatic hydrocarbon group having 1-4 carbon atoms, and n≧1)
It is a resin containing a polymer having a structural unit represented by: The number n of structural units can be appropriately selected depending on the performance required of the resin.

Since the polycarbonate resin of the present invention contains molecules having an alicyclic structure, the molecular chains are not flexible and the movement of the molecular chains is restricted, so the glass transition temperature is high and the heat resistance is good. Furthermore, it has an alicyclic structure that does not contain π electrons, has little polarization, and has reduced birefringence. Furthermore, it has no crystallinity, is amorphous, and has good transparency.

The molding method is usually injection molding, compression molding, etc., but in the case of injection molding, the shilling temperature is 300-350
It is °C.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Note that parts in the examples are parts by weight. In addition, the various physical properties obtained in the examples were measured by the following test methods. In other words, the glass transition temperature can be measured using a differential scanning calorimeter (
The temperature at the endothermic peak in DSC) was taken as the temperature at the endothermic peak.

The water absorption rate was determined based on ASTM D-570 based on the weight change after immersing a test piece (1 mm x 50 mm x 50 mm) in constant temperature water at 230° C. for 24 hours.

The light transmittance was measured using a light transmittance measuring device based on ASTM D-1003.
Measured using a ball test piece.

Birefringence (retardation, Δnd) was measured for the above test piece using a He-Ne radar.

Example 1 2.2,4.4-tetramethylcyclobutanediol-
103 parts of 1,3 and 174 parts of diphenyl carbonate were placed in a reaction vessel under a stream of purified nitrogen, 0.02 part of lithium hydroxide hydrate was added, and the mixture was heated at 215°C for 12 hours. Once the phenol has stopped distilling, reduce the temperature to 280℃.
-290°C. At this time, increase the pressure to 0.3 Dragon H
g, and the reaction was continued for 7 hours.

A polymer having an intrinsic viscosity of 1.2o at 25°C in chloroform was obtained.

The obtained polymer was heated in a vented, 4 om extruder for 25 minutes.
The pellet was extruded at a temperature of 0-300°C and the properties of the resin and test piece were measured.
Shown in the table.

Example 2 2.2,4.4-Tetramethylcyclobutanediol-
80 parts of 1,3, 2o parts of bisphenol A, 174 parts of diphenyl carbonate, 0.0 parts of lithium hydroxide dihydrate
Two parts were heated at -r210-230'C under a nitrogen stream for 3 hours. Then the temperature was increased to 280-290℃ and 0.2
= 5. It was kept in OmytHg vacuum for 3 hours.

The obtained copolycondensate had an intrinsic viscosity (25
°C) was 0.89.

The characteristics of the resin and test piece were measured in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 2.2.4.4-Tetramethylcyclobutanediol 1
．． 1 part of tetra-n-butyl titanate (Tio(C4H2)4) was added to 144 parts of dibutyl cardene and 350 parts of dibutyl cardene in a reaction vessel under a stream of purified nitrogen, and the mixture was heated at 180-210°C with stirring. heated to.

Once the distillation of n-butanol has stopped, reduce the temperature to 280-29
The temperature was raised to 0°C. At this time, the pressure was maintained at 0.2-0.5 dragon Hg for 3 hours. The intrinsic viscosity of the obtained polymer is
It was 0.89 in chloroform at 25°C.

The characteristics were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 All of Example 1 was used except that 220 parts of bisphenol A was used in place of 3 parts of 2,2,4,4-tetramethylcyclobutane-,yt-yl 1,3 io in Example 1.
Polymerization was carried out in the same manner as above. By measuring its properties, it is possible to significantly reduce the birefringence while maintaining the hydrodynamic and mechanical properties similar to those of conventional polycargonates.

Table 1

Claims (1)

[Claims] 1) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, A_1, A_2, A_3, A_4 are hydrogen atoms or aliphatic hydrocarbons having 1 to 4 carbon atoms.) A polycarbonate resin having substituted cyclobutane units as shown. 2) The above polycarbonate resin has the following general formula: ▲ mathematical formula,
There are chemical formulas, tables, etc.▼ (Here, A_1, A_2, A_3 and A_4 represent hydrogen atoms or aliphatic hydrocarbon groups having 1 to 4 carbon atoms,
n≧1. ) The polycarbonate resin according to claim 1, characterized in that the polycarbonate resin contains a molecule having a structural unit represented by: 3) The polycarbonate resin according to any one of claims 1 and 2, wherein the polycarbonate resin is a molding material for optical parts.