JPS63125522A - Optical material comprising polycarbonate resin - Google Patents

Abstract

PURPOSE:To facilitate the injection molding of an optical material and to improve its transferability, optical properties and chemical resistance, by preparing said material from a polycarbonate resin having a specified terminal group and a specified MW. CONSTITUTION:This optical material is formed from a polycarbonate resin of a viscosity-average MW of 9,000-22,000, obtained by polymerizing a m- alkenylphenol compound of formula 1 (wherein R is a 1-4C alkyl) as a terminating agent. By modifying a molding formed from a photoinitiator and said polycarbonate resin by irradiation with ultraviolet rays or electron beams, an optical material which can give a molding having a surface markedly improved in heat and chemical resistance can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a polycarbonate resin optical material that has excellent optical properties and improved heat resistance and chemical resistance. The present invention relates to an optical material that can be easily continuously molded using a method such as a molding method, and has significantly improved heat resistance and chemical resistance of the molded product's coating and surface through photocrosslinking after molding.

[Conventional technology]

Substrates used for optical applications are required to be transparent and have low optical distortion. In particular, when used as a substrate for optical disks, optical distortion can be reduced by a phase difference of ±λQnm in a single pass, preferably ±λQnm, while maintaining good transferability of groups (guide grooves) from the stamper.
is required to be within the range of l. In order to industrially manufacture such a molded article, it is advantageous to use a polycarbonate resin which has excellent transparency and dimensional stability, and to carry out the molding by injection molding or injection compression molding.

However, polycarbonate resins have a limited heat resistance (Tg': 4-73Q DEG C.) and poor resistance to organic solvents, which may limit their use in optical applications. For example, in the case of optical disk substrates, heat resistance (when forming a film on an inorganic medium by sputtering, etc.) or chemical resistance (when applying an organic dye with a solvent) becomes an issue in the process of forming the recording medium on the substrate. . Further, depending on the optical recording method, for example, in the phase change type, the heat resistance of the substrate becomes a problem because the laser power during recording or erasing is large.

On the other hand, although glass substrates and thermosetting (or photocurable) plastic substrates have excellent heat resistance and chemical resistance, they have the disadvantage of poor productivity of molded products and high costs.

[Purpose of the invention]

Therefore, the present inventors conducted intensive studies to obtain an optical molded product that can be easily molded by injection molding, etc., has excellent transferability and optical properties, and has improved heat resistance and chemical resistance. The present inventors have discovered that the problems of the prior art described above can be solved by using a polycarbonate resin having the following properties. That is, the present invention relates to general formula (I)
An optical material made of a polycarbonate resin having a viscosity average molecular weight of 9.000-400 obtained by polymerization using an m-alkenylphenol compound represented by the formula (I) as a terminal capping agent. number / represents an alkyl group of -+).

・[Structure of the invention] The present invention will be explained in detail below.

Specifically, the polycarbonate resin having a viscosity average molecular weight of 9.000 to 24000 as used in the present invention is produced by reacting one or more bisphenol compounds with a carbonate ester such as phosgene or diphenyl carbonate.

The viscosity average molecule it (M) is calculated by the following formula from η8p measured at 0° C. using a methylene chloride solution of A, Og/it of the polycarbonate resin.

7sp10 = Cwa) (/+ to 'ηsp) [η] = K
Mα In the formula C polymer concentration (11/l) [ri] Intrinsic viscosity ' O, cog K /, co, ? X/0=α0. KJ M Average molecular weight Specific examples of bisphenol compounds that can be used in the present invention include bis-(lI-hydroxyphenyl)methane, i,i-bis-(lI-hydroxyphenyl)ethane, l,/-bis- (lI-Hydroxyphenyl)propane, Tame-Corbis-(Hiro-Hydroxyphenyl)propane Sunawachi Bisphenol A% Corbis-(I-Hydroxyphenyl)butane, 4Corbis-(terhydroxyphenyl)pentane, Tame-Bis-(II- hydroxyphenyl)-3-methylbutane, co, corbis-(
4t-Hydroxyphenyl)hexane, Zhan Corbis-(
terhydroxyphenyl/v)-gumethylpentane,/
, /-bis-(lI-hydroxyphenyl)cyclopentane, /, /-bis-(41-hydroxyphenyl)
Cyclohexane, bis-(terhydroxy-3-methylphenyl)methane, l,/-bis-(terhydroxy-
3-methylphenyl)ethane, -, Corbis-(terhydroxy-3-methylphenyl)propane, Corbis-(terhydroxy-3-ethylphenyl)furopane,
High Corbis-(II-hydroxy-3-1!10propylphenyl)propane, High Corbis-(4t-hydroxy-j-aeo 7°tylphenyl)propane, Bis-(terhydroxyphenyl)phenylmethane, /,
/-bis-(terhydroxyphenyl)-/-phenylethane, l,/-bis-(4I-hydroxyphenyl)
-/-phenylpropane, bis-(terhydroxyphenyl)diphenylmethane, bis-(hiro-hydroxyphenyl)dibenzylmethane, p, II'-dihydroxydiphenyl ether, +, lI'-dihydroxydiphenyl sulfone, +, II'-dihydroxy Examples include diphenyl sulfide and phenolphthalein, with bisphenol A being particularly preferred.

The m-alkenylphenol compound represented by the general formula (I) that can be used as a terminal capping agent in the present invention is a phenol in which R is a methyl group, an ethyl group, etc., but especially m
-Isoprobenylph Furthermore, in order to obtain a resin with a desired molecular weight, a so-called known molecular weight regulator, such as phenol, p-tert-butylphenol, etc., may be used in combination with the m-alkenylphenol compound represented by the above general formula (I). is also possible.

In carrying out the present invention, a method for producing a polycarbonate resin from one or more bisphenol compounds and phosgene is specifically carried out in the presence of an inert solvent such as methylene chloride or -monodichloromethane, and a bisphenol compound is added with an alkali as an acid acceptor. Add an aqueous solution or pyridine, etc., and react while introducing phosgene.

When using an alkaline aqueous solution as an acid acceptor, use a tertiary amine such as trimethylamine or triethylamine as a catalyst.
Alternatively, the reaction rate is increased by using an isothermal grade ammonium compound such as tetrabutylammonium chloride or hensyltributylammonium bromide.

A suitable reaction temperature is 0 to 100°C.

The catalyst may be added from the beginning, or any method may be used, such as adding it after the oligomer is produced to increase the molecular weight.

In addition, when copolymerizing two or more types of bisphenol compounds, (a) first, they are simultaneously reacted with phosgene and polymerized.

(b) One is first reacted with phosgene, and after a certain amount of reaction, the other is added and polymerized.

(c) The oligomers are reacted separately with phosgene, and the oligomers are reacted and polymerized.

Any method can be used.

The terminal capping agent m-alkenylphenol compound represented by the general formula (I) used in the present invention is used in coexistence with a bisphenol compound, and the method for doing so is (a) making it coexist with the bisphenol compound from the beginning.

0) After producing an oligomer consisting of a bisphenol compound, it is allowed to coexist when increasing the molecular weight.

Any method can be used.

The amount of the m-alkenylphenol compound used as the terminal capping agent in the present invention is determined depending on the desired molecular weight.

That is, when a small amount of the bisphenol compound is used, a high molecular weight resin is obtained, whereas when a large amount is used, a low molecular weight resin is obtained. Preferably 3.3-70 for the bisphenol compound used
It is mole%. If it is less than 3.3 mol %, the resulting resin will have a high viscosity average molecular weight and poor fluidity, making it difficult to obtain an optical material with excellent transferability and small optical distortion in injection molding.

In addition, if the proportion of the terminal capping agent of the present invention bonded in the polymer molecule is too small, and the crosslinking density during ultraviolet crosslinking described below is too low, it will be difficult to achieve the extreme effects of heat resistance and chemical resistance.
On the other hand, if it exceeds 70 mol %, the molecular weight of the resin obtained is too small and becomes extremely brittle, making it difficult to obtain a satisfactory molded product.

The polycarbonate resin used in the present invention preferably has a viscosity average molecular weight in the range of t, o o o - 4 ooo. Further, Q value is usually used as a measure of fluidity, but since the resin of the present invention has a specific alkenyl group at the end, the Q value is increased when compared with the same viscosity average molecular weight.

The Q value referred to here is the melt viscosity measured with a flow tester at a temperature of 0°C, /A 01c9/cnt/f.
The amount of molten resin flowing out from the nozzle of 10×10×XL is c
It is expressed in units of c/sea.

The polycarbonate resin having the specific alkenyl group terminal described above is molded by injection molding, injection compression molding, or the like. Molding temperature is 2tO℃~daθO℃, preferably 300℃
At molding temperatures between ℃ and 310℃ and lower than StO℃,
The melt viscosity of the resin is high, making it difficult to improve the transferability and reduce optical distortion of the molded product, while when the molding temperature exceeds 4100°C, problems such as a decrease in the molecular weight of the resin, gas generation, and yellowing occur. The polycarbonate resin molded product of the present invention has lower optical distortion (phase difference) than conventional optical polycarbonate molded products, and also has improved groove transferability from the stub bar.

Further, the polycarbonate resin obtained in the present invention is put to practical use after a molded article is modified by irradiation with ultraviolet rays or electron beams in the presence of a photoinitiator. Photoinitiators that can be used here include benzophenone, benzine, p-benzoylbenzophenone, tertiary-butylphenylglyoxalate, trimethylsilylphenylglyoxalate, anthraquinone, λ-methylanthraquinone, coethylanthraquinone, dibenzyl ether, benzyldimethyl Examples include ketal. The method for making such a photoinitiator present in a resin is (1) adding it to a resin solution and removing the solvent to obtain a blend.

(2) Tri-blend with resin powder or pellets.

(3) The triblend is kneaded using an extruder.

Any method can be used.

The photoinitiator used here is 0.0% based on the weight of the resin. /
~3% by weight. That is, 0. /wt% or less, the photoinitiation effect is small, while if it is more than Jwt%, molding defects due to photoinitiator bleed out, the molecular weight of the resin decreases,
Weather resistance is likely to deteriorate.

The ultraviolet irradiation necessary for modifying the polycarbonate resin molded article obtained in the present invention can be performed using a commercially available ultraviolet lamp. Further, at this time, it is desirable to place the polycarbonate molded product in an N2 atmosphere. The irradiation time varies depending on the intensity of the light source used, the distance to the molded product, and the properties of the molded product, but is about 3 to ito seconds.

The polycarbonate resin molded product thus obtained has excellent optical properties and good heat resistance and chemical resistance, so it is suitable as various optical materials. The optical materials referred to in the present invention include, for example, lenses for copy machines, laser pickups, still cameras, video cameras, video glojictors, glasses, telescopes, audio discs (compact discs), etc. Examples include optical discs such as optical video discs, WLO W optical discs, and erasable optical discs; acute angles such as room mirrors and reflectors; and optical waveguide elements such as parts of optical connectors.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 (a) Production of oligomer H, 01000 parts, NaOH 7 parts, bisphenol A
An alkaline aqueous solution of bisphenol A containing 110 parts was charged into a reactor and stirred vigorously. After adding 530 parts of methylene chloride to this to form an emulsion, phosgene
One portion was infused over lIO minutes at a temperature of 5-10°C.

After the reaction was completed, stirring was stopped, and a methylene chloride solution containing the polycarbonate oligomer in the lower layer was collected.

The analytical values of this solution (hereinafter abbreviated as oligomer solution A) were as follows.

・Oligomer concentration, t! Ar weight% (Note/)・Terminal chloroformate group concentration llI/N (Note)・Terminal hydroxyl group concentration 0.10N (Note 3) Note 1) Evaporate to dryness and measure at °C, 2) React with aniline Neutralization titration of the obtained aniline hydrochloride with an aqueous sodium hydroxide solution J) Color development when titanium tetrachloride is dissolved in an acetic acid solution & IIA Colorimetric determination at nm (=) Polymer production Oligomer solution AcoOO part, Methylene chloride/lj parts, m
After 19 parts of -1 nopropenylphenol was charged into a reactor and stirred vigorously, 70 parts of an aqueous solution containing 7 parts of NaOH and 0.07 parts of triethylamine were added, and interfacial polymerization was carried out for 2 hours. After the reaction is completed, the polymerization solution is separated into an aqueous layer and a methylene chloride layer containing polycarbonate, and the methylene chloride layer is sequentially washed with an aqueous sodium hydroxide solution, an aqueous hydrochloric acid solution, and deionized water, and the methylene chloride is evaporated to remove flakes of polycarbonate resin. Obtained. Add to this a photoinitiator of 0,2
After adding % of benzyl dimethyl ketal (manufactured by Ciba Geigy), the mixture was melt-kneaded using an extruder and then pelletized. The obtained pellet had a viscosity average molecular weight of 11 sO.

EXAMPLE A pellet of polycarbonate resin was obtained by carrying out the same operation as in (b) of Example 1, except that the amount of m-isopropenylphenol was changed to /,'lK parts. The viscosity average molecular weight of this pellet is /7. / 00.

Example J (a) Production of oligomer H, 01000 parts, NaOH&A part, /, /-bis-(
ib
An aqueous solution consisting of o parts was charged into a reactor and stirred vigorously.

After adding 100 parts of methylene chloride to this to form an emulsion, 10 parts of phosgene was blown into the emulsion at a temperature of 3 to 70°C over 90 minutes. After the reaction was completed, stirring was stopped, and the methylene chloride solution containing the polycarbonate oligomer in the lower layer was collected. The analytical values of this solution (hereinafter abbreviated as oligomer solution B) were as follows.

Oligomer concentration - t, S weight % Terminal chloroformate group concentration O3 t normal Terminal hydroxyl group concentration 0.70 normal (measurement conditions are the same as in Example 1) (b) Polymer production Oligomer solution B 00 parts, methylene chloride lkojm, m
- Charge 63 parts of isoglobenylphenol into a reactor, stir vigorously, and then add 90 parts of an aqueous solution containing part of NaOH'/.
1 part, and 0.06 part of triethylamine were added to carry out interfacial polymerization for a period of time. After the reaction is complete, the polymerization solution is separated into an aqueous layer and a methylene chloride layer containing polycarbonate, and the methylene chloride layer is sequentially washed with an aqueous sodium hydroxide solution, an aqueous hydrochloric acid solution, and deionized water.Finally, the methylene chloride is evaporated to form a polycarbonate resin. Obtained. This was melted and kneaded with the addition of photoinitiator X in the same manner as in Example, and then formed into pellets. The viscosity average molecular weight of the obtained pellet was /(4100).

Comparative Example/, λ Commercially available polycarbonate resins (Mitsubishi Chemical Corporation) Novaretsk θ, 20 AD, and Novaretsk 0
The discs described below were prepared using

Comparative Example 3 In (b) of Example 3, p-tert-butylphenol was used instead of m-impropenylphenol.
The same operation was performed except that 76 parts were used to obtain polycarbonate resin flakes, which were then pelletized. The obtained pellet had a viscosity average molecular weight of /0.900.

Using the resins obtained in Examples 1 to 3 and Comparative Examples 1 to 3, an optical disk molding machine (Dynamelter M/4t manufactured by Taikisha Co., Ltd.
Diameter /, 7 (71E1
1. Thickness 1. Injection compression molding of a parrot disk was performed.

Birefringence was measured at points with radius of -1, tcm and 4' ICH from the center of the obtained disk using a repremeter manufactured by Mizojiri Optical Co., Ltd., and grooves were measured using an electron beam surface morphology analyzer manufactured by Elionix Co., Ltd. The depth was measured.

The results are shown in Table/.

In addition, for such a disk, the strength t in an N2 atmosphere is
o W/crIL ultraviolet rays were irradiated for a predetermined period of time.

Toluene/ethyl cellosolve = //lI (wt/wt) for chemical resistance testing of molded products! Table 1 shows the results of appearance observation after being immersed for seconds, and the groove depth measurement results after being held at 170°C for 3 minutes in an open state as a heat resistance test.

Table /) IOW HE U/G, under N2 atmosphere, 2)l
After heat treatment at 0℃ for 5 minutes η Toluene/ethyl cellmelf = /β (vt/wt)
[Effect of the Invention] As explained above, the optical material using the polycarbonate resin of the present invention has better transferability than conventional polycarbonate (using p-tertiary-butylphenol as a molecular weight regulator). It has excellent optical distortion (birefringence) and improved optical distortion (birefringence). Furthermore, after being modified by UV irradiation, it has excellent heat resistance and chemical resistance, and can be used in a wide range of applications that require optical properties and heat resistance, such as erasable optical discs.

Claims (2)

[Claims] (1) A polycarbonate resin having a viscosity average molecular weight of 9,000 to 22,000 obtained by polymerization using an m-alkenylphenol compound represented by the general formula (I) as a terminal capper. Optical materials. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents an alkyl group having 1 to 4 carbon atoms.) (2) An optical material made of a polycarbonate resin according to claim 1, wherein the polycarbonate resin is irradiated with ultraviolet rays or electron beams in the presence of a photoinitiator.