JPH01292031A - Resin composition for optical material - Google Patents

Abstract

PURPOSE:To provide the subject composition having excellent heat-resistance, moisture-resistance and mechanical strength, uniform optical properties and small birefringence and composed of a polycarbonate copolymer containing a specific recurring unit. CONSTITUTION:The objective composition is composed of a polycarbonate copolymer having the recurring unit of formula I (R1 and R2 are H, 1-6C alkyl or phenyl; the molar ratios n and m are 0.01-0.99 and n+m=1) (e.g., the unit of formula II). The copolymer can be produced by reacting bisphenols and 2,2,4,4-tetramethylcyclobutane-1,3-diol with a compound capable of forming carbonic acid ester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] 5 The present invention relates to a resin for optical materials, and particularly to digital audio discs and optical memory discs.

[Prior Art] Glass is used as a substrate for digital audio discs, optical discs, and magneto-optical discs that record and reproduce information on an information recording layer consisting of a recording layer or a light-reflecting layer, and that reproduce information formed on an information recording layer. A transparent synthetic resin disk is used.

Although glass substrates are materials with excellent transparency, heat resistance, and dimensional stability, they have problems in that they are heavy, easily broken, and have high manufacturing costs.

On the other hand, synthetic resin substrates are easier to mold than glass substrates, have less risk of breakage during handling, are lighter, and are superior to glass substrates in terms of cost. In general, such synthetic resins (resins for optical materials) are transparent, have good moldability and dimensional stability, have excellent heat resistance, moisture resistance, and mechanical strength, and are optically homogeneous. Low birefringence is required.

As such resins for optical materials, acrylic resins, epoxy resins, polystyrene resins, vinyl chloride resins, bisphenol A-based polycarbonate resins, and the like are conventionally known. However, although acrylic resin is highly transparent, optically homogeneous, and has low birefringence, it has poor dimensional stability due to its high hygroscopicity, and it warps in humid environments.
It has the disadvantage of causing twisting, etc., and also has a problem with heat resistance.

Although epoxy resin has good optical and physical properties, it has problems with moldability and is not suitable for mass production.
Although polystyrene resin has excellent processability and is low in cost, it has the drawbacks of easily producing interference fringes and increasing birefringence.

Hard vinyl chloride resin has excellent moisture absorption properties, but is inferior in processability, durability, heat resistance, moldability, etc. On the other hand, bisphenol A (2,2-bis(4'-
Polycarbonate resin obtained by reacting hydroxyphenyl (propane) with phosgene, diphenyl carbonate, etc. has excellent heat resistance, moisture resistance, impact resistance, etc., but has large birefringence, making it difficult to read information recorded on disks. The drawbacks are that sensitivity is reduced and errors are more likely to occur.

As described above, to date, a resin for optical materials that has good transparency, heat resistance, durability, and mechanical strength, is optically homogeneous, and has low birefringence has not been found.

[Problems to be Solved by the Invention] The present invention has excellent heat resistance, moisture resistance, and mechanical strength required for the above-mentioned conventional digital audio disk and optical memory disk resin, and also has optical properties. The purpose of this invention is to provide a resin for optical materials that is homogeneous and has low birefringence.

[Means for Solving the Problem] The present inventors have conducted extensive studies in order to obtain a resin for optical materials that has excellent heat resistance, moisture resistance, and mechanical strength, is optically homogeneous, and has low birefringence. Ta.

As a result, they discovered that a polycarbonate copolymer with a specific structure has excellent heat resistance, moisture resistance, and mechanical strength, as well as being optically homogeneous and having small birefringence, leading to the present invention. Na.

That is, the present invention provides a resin for an optical material that has excellent heat resistance, moisture resistance, and mechanical strength, is optically homogeneous, and has low birefringence and has the following general formula (1) as a substrate for digital audio disks and optical memory disks. ) (wherein R and R2 represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and a phenyl group, and the molar fractions n and m are arbitrary numbers from 0.01 to 0.99, respectively, The present invention relates to a resin composition for optical materials comprising a polycarbonate copolymer having a repeating unit represented by (and n + m is 1).

The polycarbonate copolymer in the present invention is.

It can be produced by reacting bisphenols and 2,2,4,4-tetramethylcyclobutane 1,3-diol with a carbonate-forming compound.

Examples of bisphenols used in the present invention include 2.
2-bis(4'-hydroxyphenyl)propane, 2,
2-bis(4'-hydroxyphenyl)butane, 2.2
-bis(4'-hydroxyphenyl)pentane, 2.
2-bis(4'-hydroxyphenyl)hexane, 2.
2-bis(4'-hydroxyphenyl)hebutane, 3.
3-bis(4'-hydroxyphenyl)pentane, 4.
4-bis(4'-hydroxyphenyl)hebutane, 1-
Phenyl-1,1-bis(4'-hydroxyphenyl)
Ethane, 1,1-bis(4'-hydroxyphenyl)
Cyclohexane, 1-phenyl-1,1-bis(4'-
Examples include hydroxyphenyl)propane and bis(4'-hydroxyphenyl)diphenylmethane.

Examples of the carbonate ester-forming compound used in the present invention include phosgene and bisaryl carbonates such as diphenyl carbonate, di-P-tolyl carbonate, phenyl-P-tolyl carbonate, di-P-talolophenyl carbonate, and dinaphthyl carbonate. It will be done.

The method for producing the copolymer includes known methods used to produce polycarbonate from bisphenol A, such as direct reaction of dihydric phenol and alcohol with phosgene, or direct reaction of dihydric phenol and alcohol with bisaryl carbonate. A method such as transesterification reaction with

In the former method of direct reaction of dihydric phenols and alcohols with phosgene, the above-mentioned bisphenols and 2,2,4
．． 4-Tetramethylcyclobutane Obtained by reacting 1,3-diol with phosgene.

As the acid binder, for example, pyridine or an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used, and as the solvent, for example, methylene chloride, chlorobenzene, xylene, etc. are used. Furthermore, a catalyst such as a tertiary ammonium salt such as triethylamine is added to promote the polycondensation reaction, and a molecular weight regulator such as pt-butylphenol or phenol is added to adjust the degree of polymerization. It is desirable to carry out the reaction, and if necessary, a small amount of an antioxidant such as sodium sulfite or hydrosulfide may be added.

Although the blending ratio of bisphenols and 2,2,4,4-tetramethylcyclobutane 1,3-diol is arbitrary, the above general formula (1) derived from bisphenols
The value of n therein is usually 0.01 to 0.99, preferably 0.2 to 0.99. The reaction temperature is usually 0 to 15
The reaction time, which is preferably carried out at a temperature in the range of 5 to 40°C, depends on the reaction temperature, but is usually 0"C5.
．． The time is 5 minutes to 10 hours, preferably 1 minute to 2 hours.

Further, during the reaction, it is desirable to maintain the pH of the reaction system at 10 or higher.

On the other hand, in the latter transesterification method, the aforementioned bisphenols and 2.2.4.4-tetramethylcyclobutane 1,3-diol are mixed with bisaryl caponate and reacted at high temperature under reduced pressure. This is usually carried out at a temperature in the range of 150 to 350°C, preferably 200 to 300°C, and the degree of vacuum is preferably 1 mmHg or less at the final stage to remove the phenols derived from the bisaryl carbonate produced by the transesterification reaction. to leave it outside. The reaction time depends on the reaction temperature, degree of pressure reduction, etc., but is usually about 1 to 4 hours.

The reaction is preferably carried out under an inert gas atmosphere such as nitrogen or argon, and the above-mentioned molecular weight regulator, antioxidant, etc. may be added as necessary.

Molding methods for obtaining a substrate by molding the resin material of the present invention include injection molding, compression molding, etc. Among these molding methods, injection molding is most preferred from the viewpoint of productivity. When forming a substrate by injection molding, it is desirable that the viscosity of the molten resin is low, and it is preferable to adjust the molecular weight of the resin material as appropriate within a range that does not adversely affect heat resistance, mechanical strength, etc.

In the above molding method, the copolymer may be molded as it is, but if necessary, various components such as phosphorous esters to prevent coloration and deterioration of transparency may be added to the copolymer. The copolymer of the present invention may be blended with a plasticizer to increase the melt index value and molded, or may be molded with other resins blended within a range that does not impair the properties of the copolymer of the present invention. .

[Effects of the invention] The polycarbonate copolymer composition of the invention thus obtained has excellent transparency, heat resistance, and mechanical strength, as well as optical homogeneity and low birefringence. Therefore, it is an extremely excellent resin for optical materials.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited only to these examples.

The various physical properties obtained in the Examples were measured by the following test methods.

(1) Light transmittance 2 Measure the light transmittance at 500 nm using a spectrophotometer (2) Birefringence 80 mm diameter section of the optical disk substrate using a Nihon Kogaku Co., Ltd. dehiscence light microscope with a Senarmon compensator attached. (3) Heat distortion temperature: Measured with a heat distortion tester according to ASTM-D-648 (4) Hardness: Measured with a pencil hardness tester according to JIS-6911 (5) Water absorption: ASTM- Measurement Example 1 according to D-570 116.1 g of 1-phenyl-1゜1-bis(4゛-hydroxyphenyl)ethane (
0.4 mol) and 2.2,4.4-tetramethylcyclobutane 1.3-diol 57°7g (0.4 mol)
After adding a solution of 2.0 g of P-tert-butylphenol dissolved in 500 ml of methylene chloride and 200 ml of pyridine as a molecular weight regulator, phosgene gas was blown in at a rate of 10,100 O/min for 15 minutes while stirring, and the reaction was carried out at room temperature for 1 hour. After the completion of the 0 reaction, the reaction product was diluted with 1500 ml of methylene chloride, washed with IN hydrochloric acid and water, and poured into 5000 ml of methanol to recover the copolymer.

When the obtained copolymer was dried at 40°C under vacuum,
Yield was 165g.

When the obtained polymer was measured by GPC, the weight average molecular weight was 2°30×10' in terms of polystyrene.
Met.

From the infrared absorption spectrum of this copolymer, 1652 cm
-' absorption based on the carbonyl group of polycarbonate was observed, and from the IH- and 13C-NMR spectra, this copolymer was confirmed to have the following repeating unit.

This copolymer was heated at a cylinder temperature of 250°C, a mold temperature of 1
It was injection molded at 20° C. into a disk with a thickness of 1.2 mm and a diameter of 120 mm. Table 1 shows the results of water absorption, light transmittance, pencil hardness, birefringence, and heat distortion temperature of the injection molded plate obtained.

Example 2 116.1 g of 1-phenyl-1゜1-bis(4-hydroxyphenyl)ethane (
0.4 mol), 14.4 g (0.1 mol) of 2.2,4.4-tetramethylcyclobutane 1,3-diol and 2.0 g of P-tert-butylphenol as a molecular weight regulator, 500 ml of methylene chloride and 2.0 g of pyridine.
After adding the solution dissolved in 00ml, phosgene gas was blown in at a rate of 10,100 O/min for 15 minutes while stirring, and the reaction was allowed to proceed at room temperature for 1 hour. After the reaction was completed, the reaction product was diluted with 1500 ml of methylene chloride, washed with IN hydrochloric acid and water, and poured into 5000 ml of methanol to recover the copolymer.

When the obtained copolymer was dried at 40°C under vacuum,
Yield was 122g.

When the obtained polymer was measured by GPC, the weight average molecular weight was 2°52×10' in terms of polystyrene.
Met.

From the infrared absorption spectrum of this copolymer, 1652 cm
Absorption based on the carbonyl group of the polycarbonate was observed at -', and from the 1) (- and 13c-NMR spectra), this copolymer was recognized to have the following repeating units.

This copolymer was injection molded under the same conditions as in Example 1.

Table 1 shows the results of water absorption, light transmittance, pencil hardness, birefringence, and heat distortion temperature of the injection molded plate obtained.

Example 3 91.3 g (0°4 mol) of 2,2-bis(4-1hydroxyphenyl)propane in a 1000 ml flask
and 2,2,4,4-tetramethylcyclobutane 1,3-
After adding a solution in which 27.7 g (0°4 mo1) of diol and 2.0 g of P-tert-butylphenol as a molecular weight regulator were dissolved in 500 ml of methylene chloride and 200 ml of pyridine, phosgene gas was introduced at 10,100 O/min while at-+. The mixture was blown in at the feeding rate for 15 minutes and allowed to react at room temperature for 1 hour. After the reaction was completed, the reaction product was diluted with 1500 ml of methylene chloride, washed with IN hydrochloric acid and water, and poured into 5000 ml of methanol to recover the copolymer.

The obtained copolymer was dried under vacuum at 40'C, and the yield was 134 g.

When the obtained polymer was measured by GPC, the weight average molecular weight was 1°83×10' in terms of polystyrene.
Met.

From the infrared absorption spectrum of this copolymer, 1651 cm
Absorption based on the carbonyl group of the polycarbonate was observed at -', and from the Mana 1) (- and !30-NMR spectra), this copolymer was recognized to have the following repeating unit.

This copolymer was injection molded under the same conditions as in Example 1.

Table 1 shows the results of water absorption, light transmittance, pencil hardness, birefringence, and heat distortion temperature of the injection molded plate obtained.

Example 4 91.3 g of 2,2-bis(4-1hydroxyphenyl)propane <0°4 mol) in a 1000 ml flask
and 2,2,4,4-tetramethylcyclobutane 1,3-
14.4 g (0.1 mo1) of diol and 2. P-tert-butylphenol as molecular weight regulator. After adding a solution in which Og was dissolved in 500 ml of methylene chloride and 200 ml of pyridine, phosgene gas was blown in at a rate of 10,100 O/min for 15 minutes while stirring, and the mixture was heated at room temperature for 15 minutes.
Allowed time to react. After the reaction was completed, the reaction product was diluted with 1500 ml of methylene chloride, washed with IN hydrochloric acid and water,
The copolymer was recovered by pouring it into 5000 ml of methanol.

The obtained copolymer was dried under vacuum at 40°C, and the yield was 102 g.

When the obtained polymer was measured by GPC, the weight average molecular weight was 1°96xlO' in terms of polystyrene.
Met.

From the infrared absorption spectrum of this copolymer, 1651 cm
Absorption based on the carbonyl group of the polycarbonate was observed in ``'', and from the 1) (- and 13C-NMR spectra), this copolymer was recognized to have the following repeating units.

This copolymer was injection molded under the same conditions as in Example 1.

Table 1 shows the results of water absorption, light transmittance, pencil hardness, birefringence, and heat distortion temperature of the injection molded plate obtained.

Comparative Example 2. A commercially available polycarbonate resin made from 2-bis(4-h droxyphenyl)propane was injection molded under the same conditions as in Example 1. Table 1 shows the results of water absorption, light transmittance, pencil hardness, birefringence, and heat distortion temperature of the injection molded plate obtained.

Claims (1)

[Claims] The following general formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (In the formula, R_1 and R_2 represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and a phenyl group, A resin composition for optical materials comprising a polycarbonate copolymer having a repeating unit represented by molar fractions n and m each being an arbitrary number from 0.01 to 0.99, and n+m being 1. .