JPH02222416A - Polycarbonate resin - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate resin suitable as a material for molded articles for optical uses, having low birefringence and high heat resistance containing specific three structural units in a specific ratio. CONSTITUTION:For example, diphenyl carbonate is blended with a dicarboxylic acid diphenyl ester and a diol and subjected to phenol removal reaction to give a polycarbonate resin which contains a structural unit shown by formula I (A is preferably methyl or phenyl), a structural unit shown by formula II (R1 to R4 is preferably methyl or n-octyl) and a structural unit shown by formula III in the molar ratio of the unit shown by the formula I + the unit shown by the formula II = the unit shown by formula III and the unit shown by formula I : the unit shown by formula II=(3:97)-(75:25) and has preferably (10:90)-(50:50) and 10,000-100,000, preferably 15,000-50,000 number-average molecular weight.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a novel polycarbonate resin.

The polycarbonate resin provided by the present invention has excellent properties such as low birefringence and high heat resistance, and can be used for optical recording media such as optical disks and optical cards; optical elements such as lenses, prisms, and diffraction gratings. Suitable as a material for optical molded products such as.

[Conventional technology]

In recent years, transparent resins with various performances have been required as materials for molded products in various fields including optical parts and automobile parts. Among optical recording media such as optical disks and optical cards, systems that allow users to record information, such as recordable and erasable discs, have appeared, and with the development of such recording systems, the level of requirements for various performances of the base material has also increased. It's getting expensive. Three properties are particularly required: low water absorption (low water absorption reactivity), low birefringence, and high heat resistance. Currently, glass and plastic materials are used as substrate materials, but glass has disadvantages such as low mass production, high cost, weight, and breakability.Plastic materials, which do not have these disadvantages, are suitable for substrate materials. Currently, it occupies the mainstream. In addition, lenses such as concave/convex lenses and Fresnel lenses, and stick materials such as diffraction gratings are becoming mainstream.

Polymethyl methacrylate (hereinafter abbreviated as PMMA) is currently used as a transparent optical material.

) and bisphenol A polycarbonate (hereinafter abbreviated as PC). Although PMMA has extremely low birefringence, it has a high water absorption (moisture absorption) property, and has the disadvantage that water absorption causes reactions and deformation, which tends to lead to a decrease in optical performance. In particular, when PMMA is used as a material for an optical recording medium consisting of a single substrate such as a digital audio disc, faithful reproduction of information may become impossible. Furthermore, a light-proof recording medium made of PMMA as a base material has some problems in heat resistance. On the other hand, PC has low water absorption, almost no water absorption and repulsion, and even in terms of heat resistance, the problem is that the n+ and -n points have large birefringence. For digital audio discs and small-diameter lenses, it is possible to suppress birefringence to below the required level by controlling molding conditions with high precision, but for 30m-diameter laser vision and large-diameter lenses, the molding conditions It is extremely difficult to control with high precision.

Conventionally, polycarbonate obtained from 2,2,4,4-tetramethyl-1,3-cyclobutanediol (hereinafter abbreviated as TMCD) or its ester and diester of carbonic acid, or TMCD or its ester and divalent Polycarbonates obtained from dioxy compounds such as phenol, bisphenol, and aliphatic diols and diesters of carbonic acid are known, and the latter has been reported to be superior to the former in terms of weather resistance and base resistance (Tokuko Sho et al. 38-26798). Polycarbonate obtained from M&, TMCD, and K
Polycarbonate obtained from TMCD and dihydric phenol has a high glass transition temperature, good heat resistance, reduced birefringence, and good transparency.
It has been reported that it can be used as a molding material for optical parts (see JP-A-63-92644).

[Problem to be solved by the invention]

The present inventors investigated the properties of polycarbonate obtained from TMCD and dihydric phenol, and found that the dihydric phenols include (1) 2.2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, When using 1.1-bis(4-hydroxyphenyl)ethane or 2.2-bis(4-hydroxyphenyl)butane, the resulting polycarbonate has a glass transition comparable to that of polycarbonate obtained from TMCD alone as a dioxy compound. temperature, but the TMC
(2) When bis(4-hydroxyphenyl)phenylmethane is used, Kll In addition, the resulting polycarbonate has poor heat decomposition resistance. It was revealed that polycarbonate has high birefringence.

Therefore, the object of the present invention is to provide a new material having a high glass transition temperature, excellent heat resistance, low birefringence, excellent thermal decomposition resistance and transparency, and good resistance to aliphatic hydrocarbon solvents. Our aim is to provide polycarbonate resins that are of high quality.

[Preparatory means for solving the problem] According to the present invention, the above object is achieved by solving the following formulas CI), (U)
and a structural unit represented by (In) (wherein A represents an alkyl group and 9 represents a phenyl group) (wherein 1, B2, B3 and R4 each represent a hydrogen atom or an alkyl group) ( III) -E-C-), and the molar fraction of the structural unit CI) and the structural unit (It
) is substantially equal to the mole fraction of the structural unit (IIl, ), and the ratio of the mole fractions of the structural unit (1) and the structural unit (II) is 3:97 to 75:25. This is accomplished by providing a polycarbonate resin with a certain number average molecular weight of 10,000 to 100,000.

The above structural units will be explained in detail.

The alkyl group represented by A in general formula (1) is:
An alkyl group having 1 to 4 carbon atoms is preferable, and examples include a methyl group, an ethyl group, an n-propyl group, an inglovir group, an n-butyl group, and an isobutyl group. In particular, it is preferable that the methyl group, ethyl group, or n-butyl group represents a phenyl group, and it is most preferable that the methyl group represents a phenyl group.

B in general formula (n), 1. B2, R3 and R4
The alkyl groups each represented by are preferably an alkyl group having 1 to 8 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-butyl group, and an n-octyl group.

A preferred example of the structural unit Cm) is shown below.

Among these, the following structural units are particularly preferred.

In particular, the following structural units are most preferred.

The molar fraction ratio of structural unit (1) and structural unit (II) is 3
In the range of 97 to 75 to 25, preferably 5 to 95
~60:40 range, preferably 10:90-50
It is in the range of 50 vs. If the molar fraction of the structural unit (1) is less than 3 molar sum of the molar fraction and the molar fraction of the structural unit (If), the desired resin of the present invention cannot be obtained; If it exceeds 7, the birefringence of the resulting resin increases, which is undesirable.

Structural unit (1) and structural unit (
II) may be used alone or in combination of two or more. Further, the resin may contain a small amount of other arbitrary structural units within a range that does not impair the properties of the resin of the present invention.

The resin of the present invention has a number average molecular weight (polystyrene equivalent) determined by gel permeation chromatography (CGPC) in the range of io, ooo to 100,000. 15,00
It is preferably in the range of 0 to so, ooo, 15,
More preferably, it is in the range of 000 to 50,000. Resins with a number average molecular weight of less than 10,000 are brittle;
Poor mechanical strength. On the other hand, the number average molecular weight is 100,00
A resin larger than 0 is not only difficult to manufacture, but also has poor moldability, which is not preferable.

The resin of the present invention can be produced according to known methods. Known methods include 1, for example, dephenolization reaction from a mixture of diphenyl carbonate and diphenyl ester of dicarboxylic acid and diol, dealcoholization reaction from a mixture of dialkyl carbonate and dialkyl ester of dicarboxylic acid and diol, phosgene and dicarboxylic acid chloride. and dehydrochlorination reaction from diol, dealkali metal chloride reaction from a mixture of phosgene, dicarboxylic acid chloride, and alkali metal salt of diol, etc., carried out in the presence of an appropriate catalyst as necessary. be done.

As for the form of the reaction, methods such as a melt method and a solution method can be adopted depending on the type of reaction, but the melt method is preferable because of the ease of reaction.

The case where the resin of the present invention is produced by a melting method will be explained below. As the catalyst, from the viewpoint of high reactivity, it is preferable to use metal lithium or lithium compounds such as lithium hydride, lithium nitride, lithium hydroxide, lithium alkoxide such as lithium ethoxide and butoxide. The amount of catalyst used is usually from 0.0001 to the total raw material.
1 molti, preferably 0.001 to 0.1
Morchi range. If the amount of catalyst used is less than the above range, the reaction rate will be extremely reduced, and if the amount of catalyst used is more than the above range, the water absorption rate of the resulting resin will increase. The polycondensation reaction is carried out by stirring the raw material compounds while heating in the presence of a catalyst in an inert gas atmosphere such as nitrogen, argon, carbon dioxide, etc., and distilling off the generated alcohol or phenol. The reaction temperature varies depending on the boiling points of the raw material compounds and the alcohol or phenol generated and the required reaction rate, but is usually in the range of 150 to 300°C. In the latter half of the reaction, the pressure of the system is reduced as necessary to drive the reaction.

The pressure at this time is in the range of 0.001 to 100 mmHg.

After the reaction is completed, the obtained resin is extruded from the reactor in the form of a strand, and then pelletized with a pelletizer, or extruded in the form of a lump and pulverized.

The resin of the present invention can be molded by any known method, for example, melt molding methods such as press molding, extrusion molding, injection molding, and injection compression molding. Also.

The resin of the present invention can also be made into a film by dissolving it in a suitable solvent and using a casting method.

In the case of melt molding, the resin temperature is usually 200-350'C1
The mold filling degree is set within the range of 40 to 150°C. During molding, heat stabilizers, light stabilizers, antistatic agents, lubricants, inorganic or organic fillers, dyes, pigments, etc. may be added to the resin of the present invention, if necessary.

The resin of the present invention can be formed into a flat plate or a simple shape and then laminated with inorganic or organic materials, or can be made into a complex shape by adhesion or fusion, or can be formed into a high-quality material such as embossing on the surface.・It is also possible to reverse the process.

When the resin of the present invention is used, for example, as a material for a substrate for a read-only optical recording medium, the resin of the present invention is first molded by injection molding or the like using a mold in which groups, signals, etc. are recorded. Obtain the substrate. On this substrate, a metal such as aluminum is deposited on the information surface by a method such as vacuum evaporation, and then a protective polymer layer is formed, or the information surface on which the surface is made of metal is coated face-to-face. Paste the two sheets together.

The information recording layer may be provided on a flat substrate made of the resin of the present invention using a photocurable resin by the 2P method.

Furthermore, the information recording layer can also be formed by, for example, providing a thin film of an inorganic material such as tellurium oxide or terbium-iron-cobalt alloy or an organic material such as cyanine dye on the surface of a molded substrate.

The resin of the present invention can be used for the following purposes by taking advantage of the excellent properties described above.

■Lighting equipment parts ■Various signboards ■Glass substitutes for windows, windshields, etc. ■Substrates for various display elements such as liquid crystals ■Various types of concave/convex lenses, Fresnel lenses, etc. used in eyeglasses, cameras, loupes, video grojectors, etc. Lenses ■ Diffraction gratings such as optical disc player pickups, spectroscopic elements, and optical low-pass filters ■ Various optical elements such as prisms, optical waveguides, and beam splitters ■ Optical fibers ■ Substrates for optical recording media such as optical disks and optical cards [Example] The present invention will be explained in detail below using examples.

In addition, the physical property values were measured according to the following method.

■Number average molecular weight: GPC (polystyrene equivalent) speed 10
°C/min).

■Heat of fusion: Using a differential thermal analyzer, the sample was heated to 260°C, held at the same temperature for 30 minutes, and then lowered to 0°C at a rate of 5°C/min, then at a rate of 10°C/min. 300
The temperature was raised to 'C, and the heat of fusion was determined.

■Light transmittance: Wavelength 4 of 9 samples formed by heat press to 2 mm thickness Q Q nrn, 600 nm and s
The transmittance of o o nm light was measured using a spectrophotometer.

■Photoelastic coefficient: 2 an x 10 m x by heat press
Soejima et al.'s method using a Helium neon laser as a light source for a plate formed to a thickness of 2°C (Komunshi Experimental Science, edited by the Editorial Committee of the Society of Polymer Science and Technology, Volume 10, p. 296,
983) Obtained in accordance with Kyoritsu Publishing (Measurement temperature: 25
℃).

■Surface hardness: Determined by pencil hardness test (JIS K 5400).

■ Saturated water absorption rate = Calculate the weight increase rate when no weight increase due to water absorption is observed in distilled water at 23℃ K
It was measured from

■Water absorption warpage: Aluminum was vapor-deposited to a thickness of 1000 on one side of a plate-like sample measuring 2 x 10 m x 2 thicknesses, and the sample was immersed in distilled water at 23°C, and the maximum value of the reaction that occurred was defined as the water absorption warp.

Practical example 1 1.1-bis(4-hydroxyphenyl)-1 was placed in a three-bottle flask equipped with a stirrer, a nitrogen gas inlet, and a cooling pipe for solidifying the distilled phenol.
- phenylethane (B15-AP) 145f (0,5 mol), TMCD 72f (0,5 mol), diphenyl carbonate 214F (1,0 mol) and lithium hydride 8.0'W (1,0 mmol). The mixture was heated to 200° C. in an oil path in a nitrogen stream and stirred for 30 minutes. Next, after stirring at 230°C for 40 minutes and at 250°C for 60 minutes, the pressure in the system was reduced to 1QwHf, and the system was stirred for an additional 30 minutes under this reduced pressure to form a pale yellow transparent resin 219F.
I got it.

The 'I (NMR spectrum (90 MHz, in deuterated chloroform, based on tetramethylsilane) of this resin is shown below.

Note that the value in parentheses represents the relative absorption intensity.

1.0-1.4 ppm: TMCIM)-CHs Noah'o)n (12) 2, 0-2.3 ppm: B
15-AP(7)-Ct(s(Dboon)Bun(3
) 4, 1-4.5 ppm: TMCD (D-n-CH
-(7) Proton [2] 6,9 to 7.4 ppm:
BLs -AP (D aromatic ring () and proton of BeφX [13] Table 2 shows the measurement results for various physical properties of the obtained resin.

Furthermore, when this resin was evaluated for resistance to hexane according to the method specified in JIS K7114, no change occurred in the appearance of the resin.

Examples 2 to 5 Various resins were obtained by carrying out the reaction in the same manner as in Example 1 except that the raw material compounds and/or the amount charged thereof were changed. The raw material compounds used and the amounts charged are shown in Table 1.

Margin below I'll show you.

Table 2 shows the measurement results for various physical properties of the resins obtained in Examples 2 to 5. The same table shows bisphenol A polycarbonate (Comparative Example 1) and TMCDMC hole-bonate (Comparative Example 2) as comparative examples.

1. Polycarbonate obtained from 1-bis(4-hydroxyphenyl)-1-phenylethane (Comparative Example 3),
Also, the physical properties of a polycarbonate (Comparative Example 4) obtained using TMCD and bisphenol A at a molar ratio of 3:7 are shown.

When these resins were evaluated for resistance to hexane according to the method specified in JIS K7114, none of the resins of the present invention showed any change in appearance. In the polycarbonate obtained in Comparative Example 2, surface whitening of the resin occurred and the transparency was completely lost.

It is clear from Table 2 below that the resin of the present invention is Comparative Example 1,
It has a smaller absolute value of photoelastic coefficient than the polycarbonate obtained in Comparative Example 3 or 4, and has a higher glass transition temperature and excellent heat resistance than the polycarbonate obtained in Comparative Example 2. Furthermore, it is clear that the resin of the present invention is completely non-quality.

〔Effect of the invention〕

The present invention provides a polycarbonate resin which has the following features and is suitable as a material for optical molded products.

(1) Possess excellent transparency.

(2) It has a high glass transition temperature of 130°C or higher and has excellent heat resistance.

(8) The absolute value of the photoelastic coefficient, which is an index of birefringence, is 55X
It should be as small as 10 oA/dyne and have low birefringence.

(4) No heat of fusion was observed by differential thermal analysis;
Be completely immoral.

(6) High surface hardness of 2H or more.

(6) The resistance due to water absorption is extremely small.

Claims (1)

[Claims] 1. Structural units (I) represented by the following formulas (I), (II) and (III) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, A is an alkyl group or a phenyl group ) (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^1, R^2, R^3 and R^4 each represent a hydrogen atom or an alkyl group.) (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ It consists of the mole fraction of the structural unit (I) and the structural unit (II).
) is substantially equal to the mole fraction of structural unit (III), and the ratio of the mole fractions of structural unit (I) to structural unit (II) is from 3:97 to 75:25. Number average molecular weight 1
0,000-100,000 polycarbonate resin. 2. The absolute value of the photoelastic coefficient at 25℃ is 4×10^-
The polycarbonate resin according to claim 1, which has a particle diameter of ^1^2 cm^2/dyne or less.