JPH0645680B2 - Materials for optical equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a material for optical equipment, and more particularly to a material suitable for a digital audio disc, an optical memory disc, and the like.

[Problems to be Solved by Prior Art and Invention]

In general, various performances are required for materials for optical devices as described above. For example, it is necessary to have excellent transparency, heat resistance, low moisture permeability, mechanical strength and the like as well as excellent optical properties. Conventionally, methacrylic resin is known as one having such properties, but it has the drawback that it is difficult to say that this is still sufficient in terms of heat resistance, low moisture permeability, impact resistance, etc. is there.

It is also known that a polycarbonate resin obtained by reacting bisphenol A (2,2-bis (4'-hydroxyphenyl) propane) with phosgene or diphenyl carbonate can be used as a material for optical devices. Although this product is excellent in heat resistance, low moisture permeability, impact resistance, etc., it has a relatively large photoelastic coefficient and is not satisfactory in fluidity during molding. Therefore, the distortion of the molded product due to the residual strain after the molding process becomes large, the birefringence of the molded product becomes large due to these, and the reading sensitivity of the information recorded on the disk is lowered.
As described above, there has not yet been obtained a sufficiently satisfactory material for optical devices.

Therefore, the present inventors maintain the excellent properties of the polycarbonate resin such as heat resistance and mechanical strength, and improve the optical properties by improving the flowability and the photoelastic coefficient which are the drawbacks of the polycarbonate resin. We have conducted intensive research to develop such materials.

[Means for solving problems]

As a result, they have found that a specific copolymer can achieve the above object, and have completed the present invention based on this finding.

That is, the present invention has the general formula [In the formula, R ¹ represents an alkylene group. ] Or the general formula [In the formula, R ² represents a polyoxyalkylene group. ] The repeating unit [I] represented by [In the formula, R ³ and R ⁴ each represent an alkyl group, an aryl group, or an aralkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom. Show. A repeating unit [II] represented by the formula [1], wherein the repeating unit [I] has a molar fraction of 1 to 50%, and a solution of methylene chloride as a solvent at a concentration of 0.5 g / d
Reduced viscosity [η _sp / c] at ℃ is 0.3-1.0 d / g
The present invention provides a material for optical equipment, which comprises the copolymer of

The degree of polymerization of the copolymer having the repeating units [I] and [II] may be appropriately determined according to the type of optical equipment.
2 of 0.5 g / d concentration solution using methylene chloride as a solvent
Reduced viscosity [ηsp / c] at 0 ° C is 0.3 to 1.0 d /
It should be polymerized to give a copolymer of g, preferably 0.35 to 0.50 d / g. Here, the reduced viscosity is 0.
If it is less than 3 d / g, the copolymer will have low mechanical strength, and if it exceeds 1.0 d / g, the fluidity will decrease,
The residual strain is large and the optical properties are low.

Further, the mole fraction of the repeating unit [I] in the copolymer is 1
It should be -50%, preferably 5-30%. If this value is less than 1%, the fluidity during molding is low, the residual stress is large, and the birefringence is not sufficiently low. Also, 5
If it exceeds 0%, the heat resistance is lowered, which is not preferable.

The general formula In the repeating unit [I] represented by, R ¹ is an alkylene group as described above. There are various alkylene groups, but preferably an alkylene group having 2 to 15 carbon atoms, specifically, a polypropylene group such as an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a propylene group. , Butylene group and the like.

Also the general formula In the repeating unit [I] represented by, R ² is a polyoxyalkylene group, and this polyoxyalkylene group is an oxyalkylene having 2 to 15 carbon atoms, specifically, an oxyethylene group (-OCH ₂ CH ₂ -), oxy trimethylene group (-OCH ₂ CH ₂ CH ₂ -), oxytetramethylene group (-OCH ₂ CH ₂ CH ₂ CH ₂ -) which units of oxyalkylene groups are polymerized about 2-20 such Examples thereof include poly (oxyethylene) group, poly (oxytrimethylene) group, and poly (oxytetramethylene) group.

Therefore, if the repeating unit [I] is specifically shown, [In formula, n shows 2-20. ] Etc. can be enumerated.

On the other hand, the general formula showing the repeating unit [II] In, R ^{3 to} R ⁶ are as described above. That is,
R ³ and R ⁴ each represent an alkyl group such as a methyl group, an ethyl group and a propyl group, an aryl group such as a phenyl group and a tolyl group, or an aralkyl group such as a benzyl group and a phenylethyl group. R ⁵ and R ⁶ each represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a chlorine atom, a bromine atom or the like.

The copolymer in the present invention has the above repeating units [I] and [II], and there are various copolymers such as random copolymers, block copolymers and alternating copolymers.

The above-mentioned copolymer can be produced by various methods. [In the formula, R ^{3 to} R ⁶ are the same as the above], and a bisphenol compound represented by the general formula HO-R ¹ -OH ... (B) [wherein R ¹ is the same as the above] Compounds containing, specifically ethylene glycol, trimethylene glycol (1,3-propanediol), tetramethylene glycol (1,4-butanediol), or general formula HR ² -OH ... (C) [wherein , R ² is the same as the above], and specifically, it can be produced by polycondensing an aliphatic chain-containing compound, specifically, polyethylene glycol, polypropylene glycol or the like with phosgene. In addition to the method according to the method for producing a polycarbonate by the phosgene method, it can be performed according to a method for producing a transesterification method polycarbonate using diphenyl carbonate or the like. In this case, the bisphenol compound represented by the general formula (A) and the aliphatic chain-containing compound represented by the general formula (B) or (C) are directly mixed as a monomer to form phosgene or a carbonic acid ester such as diphenyl carbonate. Or a bisphenol compound represented by the general formula (A) and phosgene are polycondensed in advance to obtain an oligomer, and the oligomer and the aliphatic group represented by the general formula (B) or (C) are reacted. It may be reacted with a chain-containing compound. In addition, the general formula (B) in advance
Alternatively, the aliphatic chain-containing compound represented by (C) may be polycondensed with phosgene or the like to form an oligomer, and this may be reacted with the bisphenol compound represented by the general formula (A). Further, the bisphenol compound and the aliphatic chain-containing compound may be separately reacted with phosgene or the like to produce respective oligomers, and the oligomers may be reacted with each other.

Further, in any of the above cases, a mixture of an oligomer and a monomer may be used instead of the individual one.

The conditions for this polycondensation cannot be uniquely determined depending on the type of raw materials used, the degree of polymerization of the desired copolymer, etc., but normally it is usually a halogenated hydrocarbon such as methylene chloride or chlorobenzene, or pyridine. A suitable catalyst, alkali, molecular weight modifier, etc. may be used in a solvent, preferably in a methylene chloride solvent. Here, various monohydric phenols can be used as the molecular weight modifier, and preferred examples include phenol, tertiary butylphenol, phenylphenol, cumylphenol and the like.

The repeating unit [I] constituting the copolymer of the present invention is formed by the reaction of the aliphatic chain-containing compound represented by the general formula (B) or (C) with phosgene, and the repeating unit [II] is It is formed by the reaction of the bisphenol compound represented by the general formula (A) with phosgene or the like. Therefore, the bisphenol compound represented by the general formula (A) or the aliphatic chain represented by the general formula (B) or (C) is selected depending on the desired mole fraction of the repeating units [I] and [II] in the copolymer. The amount of the contained compound used may be appropriately selected. When forming a disk or the like using the copolymer of the present invention, usual additives such as an antioxidant and an ultraviolet absorber may be added.

〔The invention's effect〕

The copolymer of the present invention thus obtained has a smaller photoelastic coefficient than conventional polycarbonate resins, and has good moldability and little molding strain, resulting in small birefringence and excellent optical properties. It is a thing. Moreover, it has excellent heat resistance and mechanical strength. Therefore, when the copolymer of the present invention is used as a material for various optical devices, the optical properties are improved, so that the reading sensitivity of the information recorded on the disk is high and the occurrence of errors is small, that is, the recording information Excellent optical equipment with high fidelity of reproduction can be obtained. Further, since it is a material that is good in terms of both thermal and mechanical strength, an optical device made using it can operate stably under various conditions.

Therefore, the material (copolymer) of the present invention can be effectively used as a material for optical devices such as digital audio disks and optical memory disks.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 67 g of 2,2-bis (4'-hydroxyphenyl) propane
Phosgene gas was blown at a rate of 800 m / min at 15 ° C. while vigorously stirring a mixed solution of 450 m of a 6% concentration aqueous sodium hydroxide solution and 200 m of methylene chloride, and the pH of the reaction system dropped to 9. At this point, the supply of phosgene gas was stopped and the mixture was allowed to stand and separate to obtain a polycarbonate oligomer having a chloroformate group terminal in the organic layer and a degree of polymerization of 2 to 3.

Next, the above polycarbonate oligomer was dehydrated with anhydrous sodium sulfate, and then 60 m of a methylene chloride solution of this polycarbonate oligomer was further diluted with methylene chloride to a total of 150 m. To this, 0.2 g of paratertiary-butylphenol was added as a molecular weight regulator,
A solution prepared by dissolving 2.0 g of 1,4-butanediol in 15 m of pyridine was added dropwise, and the mixture was reacted for 1 hour while stirring. Then, 100 m of methylene chloride was added to the obtained reaction product, washed with hydrochloric acid and water, respectively, and the organic layer was separated and put into methanol 2 to obtain a white polycarbonate copolymer.

The obtained copolymer has 0.5 g of methylene chloride as a solvent.
Reduced viscosity [ηsp /
c] was 0.39 d / g, and the content of the repeating unit [I] was 22 mol% as determined by nuclear magnetic resonance spectroscopy. Further, the glass transition temperature, the melt index value under a load of 2160 g at 280 ° C., and the photoelastic coefficient were measured. The results are shown in Table 1.

Example 2 In the process for producing the polycarbonate oligomer of Example 1, 1,2-bis (4'-hydroxyphenyl) -1- was used instead of 2,2-bis (4'-hydroxyphenyl) propane.
Polyethylene glycol with a molecular weight of about 600, using 60 g of phenylethane and replacing 1,4-butanediol 1
Example 1 was repeated except that 2.0 g was used. The results are shown in Table 1.

Example 3 In the process for producing the polycarbonate oligomer of Example 1, 2,2-bis (3'-sec-butyl-4'-hydroxyphenyl) pyropane 65 g was used instead of 2,2-bis (4'-hydroxyphenyl) propane. Was used and the amount of 1,4-butanediol used was 1.0 g, and the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 4 In the production process of the polycarbonate oligomer of Example 1, 2,2-bis (3′-methyl-4′-hydroxyphenyl) -4- was used instead of 2,2-bis (4′-hydroxyphenyl) propane. The procedure of Example 1 was repeated except that 65 g of methylpentane was used and the amount of 1,4-butanediol used was 1.0 g. The results are shown in Table 1.

Comparative Example 1 The properties of a commercially available polycarbonate prepared from 2,2-bis (4′-hydroxyphenyl) propane as a raw material were measured in the same manner as in Example 1. The results are shown in Table 1.

Claims (3)

[Claims] 1. A general formula [In the formula, R ¹ represents an alkylene group. ] Or the general formula [In the formula, R ² represents a polyoxyalkylene group. ] The repeating unit [I] represented by [In the formula, R ³ and R ⁴ each represent an alkyl group, an aryl group, or an aralkyl group having 1 to 5 carbon atoms, and R ⁵ and R ⁶ each represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom. Show. A repeating unit [II] represented by the formula [1], wherein the repeating unit [I] has a mole fraction of 1 to 50%, and a solution of 0.5 g / dl in 20
Reduced viscosity [η _sp / c] at ℃ is 0.3-1.0dl / g
Material for optical equipment consisting of the copolymer of. 2. The material for optical equipment according to claim ¹ , wherein R ¹ in the general formula representing the repeating unit [I] is an alkylene group having 2 to 15 carbon atoms. 3. R ² in the general formula representing the repeating unit [I] is ² to 2 for an oxyalkylene unit having 2 to 15 carbon atoms.
The material for optical equipment according to claim 1, which is obtained by polymerizing 20 pieces.