JP2556864B2 - Optical materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel optical material. More specifically, the present invention is suitable for use as an element for optical equipment such as a lens, a prism, an audio disc, an optical memory disc, and an optical fiber.
The present invention relates to an optical material composed of a polycarbonate copolymer which has excellent mechanical strength, moisture resistance and the like, has a small optical anisotropy, and can suppress the occurrence of birefringence during molding.

[Prior Art] Conventionally, polycarbonate resins have been widely used in many fields as engineering plastics because of their excellent transparency, heat resistance, mechanical strength, etc., and in recent years, these properties have been utilized. Then, it has come to be used as a material for optical device elements such as lenses, prisms, audio disks, optical memory disks, and optical fibers.

By the way, the optical material is required to have heat resistance, moisture resistance, mechanical strength, etc. in addition to excellent optical characteristics, and conventionally, an acrylic resin, particularly a polymethylmethacrylate resin has been mainly used. However, in this acrylic resin, the heat resistance is not always sufficient and inferior in the moisture resistance, therefore, the optical device element made of this material is unavoidably deteriorated in performance due to moisture absorption during storage, and further,
It has a drawback that it cannot be used in the field where heat resistance is required.

On the other hand, since polycarbonate is excellent in heat resistance and moisture resistance and has good transparency, it has recently attracted attention as an optical material. However, the conventional polycarbonate resin uses 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A) as a starting material and has a molecular chain of a molecular chain at the time of molding such as injection molding or compression molding. Optical anisotropy is likely to occur due to orientation and residual stress, and birefringence is likely to occur due to this. Therefore, when it is used as a material for an optical device element that requires high precision, its application is subject to restrictions. For example, in an optical disc used for reading and writing information with light using a laser beam, it cannot be used as a memory for a computer or the like, but is used only as a so-called compact disc for audio.

Therefore, there has been a strong demand for the development of an optical material that is excellent in transparency, heat resistance, moisture resistance, mechanical strength, and the like, and that can suppress the occurrence of birefringence during molding or the like.

[Problems to be Solved by the Invention] The present invention has been made in response to such a demand, and in the molding process or the like without impairing the transparency, heat resistance, moisture resistance, mechanical strength and the like which a polycarbonate resin originally has. The purpose of the present invention is to provide an optical material made of a novel polycarbonate resin having a small optical anisotropy, which can suppress the occurrence of birefringence at a low level.

[Means for Solving Problems] The inventors of the present invention have conducted extensive studies to develop an optical material made of a polycarbonate resin having the above-mentioned excellent characteristics, and as a result, have found that a polycarbonate-based copolymer having a specific structure can be used. It was found that coalescence could meet the purpose, and the present invention was completed based on this finding.

That is, the present invention provides (A) general formula (X in the formula is a linear or branched alkylene group which may be substituted with an aryl group, a cycloalkylene group, -O
-, - S -, - SO- or -SO ₂ -, n is or 1, R ¹ and R
² is a halogen atom, an alkyl group, an alkoxy group or an aryl group, 1 and m are 0 or an integer of 1 to 3, and when 2 or more R ¹ or 2 or more R ² are contained, they may be the same. Which may be different), and (B) a general formula (X ′ in the formula is a linear or branched alkylene group optionally substituted with an aryl group, a cycloalkylene group,-
O -, - S -, - SO- or -SO ₂ -, n 'is 0 or 1, R
³ and R ⁴ are a halogen atom, an alkyl group, an alkoxy group or an aryl group, l ′ and m ′ are 0 or an integer of 1 to 4, and include 2 or more R ³ or 2 or more R ^4. Which may be the same or different) and which provides an optical material composed of a polycarbonate copolymer having a molar ratio of 10: 1 to 1:10. Is.

 Hereinafter, the present invention will be described in detail.

In the polycarbonate copolymer used as the optical material of the present invention, the monomer constituting the repeating unit represented by the general formula (I) has a general formula: (Wherein X, n, R ¹ , R ² , l and m have the same meanings as described above).
From the viewpoint of easy availability, it is usually advantageous to use the bisphenols in which R ¹ and R ² in the general formula (III) are the same.

Representative examples of bisphenols represented by the general formula (III) include 2,2-bis (3-cyclohexyl-4).
-Hydroxyphenyl) propane, 2,2-bis (2-cyclohexyl-4-hydroxyphenyl) propane,
2-bis (3-methyl-4-hydroxy-5-cyclohexylphenyl) propane, 2,2-bis (2,3-dimethyl-4-hydroxy-5-cyclohexylphenyl) propane, 2,2-bis (3- Methoxy-4-hydroxy-5
-Cyclohexylphenyl) propane, 1-phenyl-
1,1-bis (3-cyclohexyl-4-hydroxyphenyl) ethane, 1,1-bis (3-cyclohexyl-4-)
Hydroxyphenyl) -1,1-diphenylmethane, 3,3-
Bis (3-cyclohexyl-4-hydroxyphenyl)
Pentane, 1,2-bis (3-cyclohexyl-4-hydroxyphenyl) ethane, 1,1-bis (3-cyclohexyl-4-hydroxyphenyl) cyclohexane, bis (3-cyclohexyl-4-hydroxyphenyl) sulfone, 2 , 2-bis (3-cyclohexyl-4-hydroxy-6-chlorophenyl) propane, bis (3-cyclohexyl-4-hydroxyphenyl) sulfoxide, bis (3-cyclohexyl-4-hydroxyphenyl) ether, bis (3-cyclohexyl) -4-hydroxyphenyl) thioether, 3,3'-dicyclohexyl-4,
4'-dihydroxybiphenyl etc. are mentioned.

On the other hand, the monomer constituting the repeating unit represented by the general formula (II) has a general formula (Wherein X ′, R ³ , R ⁴ , n ′, 1 ′ and m ′ have the same meanings as described above).
As the bisphenols, it is usually advantageous to use ones in which R ³ and R ⁴ in the general formula (IV) are the same, from the viewpoint of easy availability.

Typical examples of the bisphenols represented by the general formula (IV) include 2,2-bis (4-hydroxyphenyl).
Propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (2,3-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3-methoxy-4-) Hydroxyphenyl) propane, 1,2-bis (4-hydroxyphenyl) ethane, 1-phenyl-1,
1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1,1-diphenylmethane, 3,3-bis (4-hydroxyphenyl) pentane,
1,1- (4-hydroxyphenyl) cyclohexane, 2,2
-Bis (3-phenyl-4-hydroxyphenyl) propane, bis (3-phenyl-4-hydroxyphenyl)
Sulfo, 2,2-bis (3-chloro-4-hydroxyphenyl) propa, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) thioether, bis (4
-Hydroxyphenyl) ether, 4,4'-dihydroxydiphenyl and the like.

The method for producing a polycarbonate copolymer using the bisphenols represented by the general formula (III) and the bisphenols represented by the general formula (IV) is not particularly limited, and a conventionally known method such as bisphenol is available. Method of interfacial polycondensation of compounds with phosgene, transesterification of bisphenols with diaryl carbonates such as diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate and dinaphthyl carbonate By a reaction method, a method by a transesterification reaction of a bisphenol with a dialkyl carbonate such as dimethyl carbonate or diethyl carbonate, or a transesterification reaction of a fatty acid ester of a bisphenol with the dialkyl carbonate. Method, the bisphenols in the presence of a noble metal catalyst such as palladium, such as direct method of producing a polycarbonate by reacting with carbon monoxide and chlorine, can be used any method.

Next, the method for producing the polycarbonate copolymer used as the optical material of the present invention will be described by taking the interfacial polycondensation method using phosgene as an example. First, in a suitable solvent, for example, methylene chloride, chlorobenzene, xylene, etc. To the above, for example, bisphenols represented by the general formula (III) and an acid binder are added, and phosgene gas is blown thereinto at a temperature of usually 0 to 40 ° C to prepare a polycarbonate oligomer having a chloroformate group terminal. To do.

Next, the bisphenols represented by the general formula (IV), the terminal terminator, and, if necessary, the above-mentioned solvent, acid binder, catalyst and the like are added to this reaction liquid, and the mixture is usually 0 to 40 ° C.
By subjecting the polymer to polycondensation at a temperature in the range, the desired polycarbonate-based copolymer can be obtained.

Examples of the acid binder used here include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic bases such as pyridine. Further, as the catalyst, for example, a tertiary amine such as triethylamine, a quaternary ammonium salt, or the like is used. Further, the terminating agent is used for adjusting the molecular weight, and examples thereof include pt-butylphenol and phenylphenol.

Regarding the molecular weight of the polycarbonate-based copolymer used as the optical material of the present invention, the reduced viscosity [ηs at a temperature of 20 ° C. of a 0.5 g / dl concentration solution using methylene chloride as a solvent is
p / c] is preferably 0.2 dl / g or more. This reduced viscosity
If it is less than 0.2 dl / g, the mechanical strength is insufficient,
Not preferred.

The content ratio of the repeating unit represented by the general formula (I) and the repeating unit represented by the general formula (II) in the polycarbonate copolymer is in the range of 10: 1 to 1:10. is necessary. If the number of repeating units represented by the general formula (I) is less than this, the improvement of optical properties becomes insufficient, and if it is more than this, the heat resistance becomes insufficient.

When an optical material composed of the polycarbonate copolymer of the present invention is molded to produce an optical device element, the molding method is not particularly limited, and a method conventionally used for molding a polycarbonate resin, such as injection molding, is used. Method, compression molding method, or an arbitrary method can be selected from the low-linking method and the micromolding method, which are the poor methods of injection molding and compression molding.

Among these molding methods, the effects of the present invention are large, such as the molding method in which the degree of birefringence that occurs during the molding of ordinary polycarbonate resin is relatively large, and for example, the injection molding method is most advantageous.

Furthermore, in the case of molding a polycarbonate copolymer having low fluidity, for example, after molding in a state in which the fluidity is improved by adding a small amount of a crosslinkable monomer, γ rays,
A method of irradiating an electron beam, an X-ray, an ultraviolet ray or the like to crosslink and cure can be used.

The optical element obtained from the optical material of the present invention,
For example, so-called lenses for steel cameras, video cameras, telescopes, eyeglasses, contact lenses, sunlight concentrating, prisms such as pentaprisms,
Concave mirrors, mirrors such as polygons, optical elements such as optical fiber optical waveguides, discs such as video discs, audio discs, optical memory discs, and the like that can exhibit functions by transmitting or reflecting light be able to.

[Effects of the Invention] The optical material comprising the polycarbonate copolymer of the present invention is excellent in transparency, heat resistance, mechanical strength, moisture resistance and the like, and has a small optical anisotropy, resulting in birefringence during molding. It is possible to suppress the occurrence of heat generation at a low level, and by changing the copolymer composition, various characteristics such as optical characteristics as well as heat resistance can be controlled in various ways.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

Example 1 100 g (0.25 mol) of 2,2-bis (3-cyclohexyl-4-hydroxyphenyl) propane was added to a baffled flask having an internal volume of 1 together with 480 ml of a 6 wt% aqueous solution of sodium hydroxide and 250 ml of methylene chloride. While stirring vigorously, phosgene gas was blown at a rate of 900 ml / min for 14 minutes. Next, the product was separated by standing to obtain a methylene chloride solution of a polycarbonate oligomer having a chloroformate group terminal and a polymerization degree of 2 to 3.

Then dilute 300 ml of this solution to 450 ml with methylene chloride,
As a molecular weight regulator, 0.5 g of pt-butylphenol and 2,
A solution of 23 g of 2-bis (4-hydroxyphenyl) propane dissolved in 140 ml of an aqueous solution of sodium hydroxide having a 2N concentration is added, 3 ml of sodium hydroxide having a concentration of 12N and 1.0 ml of a 5% by weight aqueous solution of triethylamine as a catalyst are added. , Reacted for 1 hour with vigorous stirring. After the reaction was completed, the product was diluted with 500 ml of methylene chloride, diluted with water,
0.01N sodium hydroxide aqueous solution, 0.01N hydrochloric acid,
After washing with water in this order, it was poured into methanol 5 to obtain a copolymer.

The structure of this product was as follows from the NMR spectrum.

Examples 2 to 16 Copolymers were produced in the same manner as in Example 1 using the bisphenols shown in Table 1. The structures of these copolymers according to the NMR spectrum are shown in Table 1.

Comparative Examples 1 to 3, 2,2-bis (3-cyclohexyl-) in Example 1
Instead of 4-hydroxyphenyl) propane, 2,2-
58 g of bis (4-hydroxyphenyl) propane (Comparative Example 1), 74 g of 1-phenyl-1,1-bis (4-hydroxyphenyl) ethane (Comparative Example 2), 2,2-bis (3-methyl-4-) Hydroxyphenyl) propane 65 g (Comparative Example 3)
A polymer was obtained in the same manner as in Example 1, except that

As described above, the reduced viscosity ηsp / c, the glass transition temperature Tg, and the photoelastic coefficient of the polymers obtained in Examples 1 to 16 and Comparative Examples 1 to 3 were measured. Table 2 shows the results.

The reduced viscosity is 0.5 g / l with methylene chloride as the solvent.
The value of the dl concentration solution at 20 ° C was determined.

Claims (1)

(57) [Claims] 1. A general formula (A) (X in the formula is a linear or branched alkylene group which may be substituted with an aryl group, a cycloalkylene group, -O
-, - S -, - SO- or -SO ₂ -, n is 0 or 1, R ¹ and R ² is a halogen atom, an alkyl group, an alkoxy group or an aryl group, l and m are 0 or an integer of 1 to 3 And when two or more R ^1's or two or more R ^2's are contained, these may be the same or different, and (B) a general formula (X ′ in the formula is a linear or branched alkylene group optionally substituted with an aryl group, a cycloalkylene group,-
O -, - S -, - SO- or -SO ₂ -, n 'is 0 or 1, R
³ and R ⁴ are a halogen atom, an alkyl group, an alkoxy group or an aryl group, l ′ and m ′ are 0 or an integer of 1 to 4, and include 2 or more R ³ or 2 or more R ^4. These may be the same or different) and an optical material composed of a polycarbonate copolymer having a molar ratio of 10: 1 to 1:10.