JPH0625398A - Polycarbonate resin with high refractive index and low birefringence - Google Patents

Abstract

PURPOSE:To provide the subject resin excellent in transparency, thus useful for various optical applications such as optical lens and optical disks, with bis(oxyphenylene)fluorene unit incorporated therein at a specified rate. CONSTITUTION:The objective resin is made up of constituent units of respective formulas I and II (R1-R6 are each H, halogen, etc.; W is single bond, alkylidene, etc.; (m) and (n) are each 1-4), where the content of the unit of the formula I is 41-95mol%, and has the following characteristics: (1) photoelastic constant: 50X10<-13>cm<2>/dyne; and (2) specific viscosity: >=0.19 determined at 20 deg.C for a solution prepared by dissolving 0.7g of the resin in 100ml of methylene chloride. This resin can pref. be obtained by interfacial polycondensation of 9,9-bis(4- hydroxyphenyl)fluorene and bisphenol A with phosgene, or by ester interchange reaction of the components A and B with a diester carbonate (pref., diphenyl carbonate).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polycarbonate resin having improved refractive index and birefringence. More specifically, it relates to a polycarbonate resin having a specific amount of 9,9-bis (4-oxyphenylene) fluorene structural unit, a high refractive index, low birefringence and excellent transparency. Such a resin makes use of its characteristics, a CD pickup lens,
It is extremely useful as a material for optical lenses such as Fresnel lenses, screens for projection televisions, films such as retardation films, and disks.

[0002]

2. Description of the Related Art Conventionally, a polycarbonate resin obtained by reacting a carbonate precursor substance with 2,2-bis (4-hydroxyphenyl) propane has excellent transparency, heat resistance, mechanical properties and dimensional stability. Therefore, it is widely used in many fields as engineering plastics. In particular, it has many uses as an optical material because of its excellent transparency. However, such a polycarbonate resin has a drawback that it has a large birefringence as an optical material.

[0003]

The object of the present invention is to provide a polycarbonate resin having a high refractive index and a low birefringence without impairing the transparency of the polycarbonate resin.

The inventors of the present invention have conducted extensive studies to achieve this object. As a result, a polycarbonate copolymer having a specific proportion of 9,9-bis (4-oxyphenylene) fluorene structural units introduced therein achieves the above object. Find out that
The present invention has been reached.

9,9-bis (4-hydroxyphenyl)
Aromatic polycarbonate resins obtained by reacting fluorene with a carbonate precursor are known, and it is also known that this polymer has a high refractive index and good heat resistance. However, when this homopolymer was synthesized, a large amount of a gel-like substance insoluble in the solvent was produced, and the yield of the solvent-soluble component was at most 60 to 70%, which was poor in practicality. Also,
When attempting to melt mold this, there was a problem that the melt viscosity was too high to mold.

However, the aromatic polycarbonate resin obtained by copolymerizing a specific amount of 9,9-bis (4-oxyphenylene) fluorene structural unit does not have such drawbacks, but also has a high refractive index and a low birefringence. It is surprising to show.

[0007]

The present invention provides the following general formula [1]:

[0008]

[Chemical 3]

[Wherein R _{1 to} R ₄ are a hydrogen atom, a halogen atom, a phenyl group or an alkyl group having 1 to 3 carbon atoms,
It may be the same or different. ] And the following general formula [2]

[0010]

[Chemical 4]

[Wherein W is a single bond, an alkylidene group, a cycloalkylidene group, a phenyl group-substituted alkylidene group, a sulfone group, a sulfide group or an oxide group, and R ₅ and R ₆ are a hydrogen atom, a halogen atom, a phenyl group, It is an alkyl group having 1 to 3 carbon atoms and may be the same or different, and m and n are each an integer of 1 to 4. ] The structural unit represented by the general formula [1] is contained, and the photoelastic constant is 50x10.
^-13 cm ² / dyne or less, and 0.7 g dissolved in 100 ml of methylene chloride and having a specific viscosity of 0.19 or more measured at 20 ° C., relating to a high refractive index and low birefringence polycarbonate resin. .

Polycarbonate resins of interest in the present invention are prepared by reacting 9,9-bis (4-hydroxyphenyl) fluorenes with one or more other dihydric phenol compounds, end-capping agents and carbonate precursor materials. Manufactured. It is usually produced by an interfacial polycondensation method using phosgene or a transesterification reaction using a carbonic acid diester.

9,9-bis (4-hydroxyphenyl)
Examples of fluorenes include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, and 9,9-bis (3-ethyl-4-hydroxyphenyl). ) Fluorene and the like, and particularly 9,9-bis (4-hydroxyphenyl) fluorene is preferable.

Other dihydric phenols include, for example, bis (4-hydroxyphenyl) methane and 2,2-bis (4
-Hydroxyphenyl) propane [commonly known as bisphenol A], 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-bis (4-hydroxyphenyl) heptane, 2,2-bis (4-hydroxy) -3,5
-Dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bis (4-hydroxyphenyl) oxide, bis (3,5
-Dichloro-4-hydroxyphenyl) oxide,
4,4'-dihydroxydiphenyl, 3,3'-dichloro-4,4'-dihydroxydiphenyl, bis (4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (4 -Hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfoxide and the like are mentioned, and bisphenol A is particularly preferable. A monohydric phenol such as p-tert-butylphenol is used as the terminal stopper.
The amount used is usually 0.01 with respect to the dihydric phenol used.
It is -10 mol%, preferably 0.03-8 mol%.

In the interfacial polycondensation reaction using phosgene,
Usually, 9,9-bis (4-hydroxyphenyl) fluorenes and other dihydric phenol are dissolved in an aqueous solution of an acid binder and reacted in the presence of an organic solvent. As the acid binder, for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used, and as the organic solvent, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. The reaction is usually 0 to 40 ° C., preferably 20
The process is completed in about 10 minutes to 10 hours at -30 ° C. It is preferable to keep the pH of the reaction system at 10 or higher as the reaction progresses. A catalyst may be used to accelerate the reaction, and examples of the catalyst include triethylamine and tetra-n.
Examples include tertiary amines such as -butylammonium bromide and tetra-n-butylphosphonium bromide, quaternary ammonium compounds, and quaternary phosphonium compounds. Furthermore, if necessary, an antioxidant such as hydrosulfite can be added.

In the transesterification reaction using a carbonic acid diester, 9,9-bis (4-hydroxyphenyl) fluorenes and other dihydric phenol compounds are formed by stirring the carbonic acid diester while heating in an inert gas atmosphere. It is carried out by distilling alcohol or phenol.
The reaction temperature varies depending on the boiling point of the alcohol or phenol to be produced, but is usually in the range of 120 to 350 ° C.
In the latter stage of the reaction, the system is depressurized to facilitate the distillation of the alcohol or phenol produced and complete the reaction. Examples of the carbonic acid diester include diphenyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate and the like. Of these, diphenyl carbonate is particularly preferable.

A polymerization catalyst can also be used to accelerate the polymerization rate. As the polymerization catalyst, hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide and potassium hydroxide, and hydroxides of boron and aluminum can be used. Alkaline metal salts, alkaline earth metal salts, quaternary ammonium salts, alkali metal and alkaline earth metal alkoxides, alkali metal and alkaline earth metal organic acid salts,
Zinc compounds, boron compounds, silicon compounds, germanium compounds, organotin compounds, lead compounds, antimony compounds, manganese compounds, titanium compounds,
It is possible to use a catalyst which is usually used for esterification reaction and transesterification reaction of zirconium compounds and the like.
The catalyst may be used alone or in combination of two or more kinds. The amount of these catalysts used is 0.0001 to 1% by weight, preferably 0.000, based on the dihydric phenol as a raw material.
It is selected in the range of 5 to 0.5% by weight.

The molecular weight of the polycarbonate resin is 0.19 or more, preferably 0.26 to, expressed as a specific viscosity measured at 20 ° C. in a methylene chloride solution having a concentration of 0.7 g / dl.
0.45. If it is less than 0.19, the obtained molded product becomes brittle, which is not suitable.

In the polycarbonate resin of the present invention, the content ratio of the structural unit represented by the general formula [1] and the structural unit represented by the general formula [2] is 41 to 95 mol% of the former and 59 to 5 of the latter. Mol%. When the content of the structural unit represented by the general formula [1] is less than 41 mol%, the birefringence is not sufficiently lowered, and when it exceeds 95 mol%, the birefringence is remarkably reduced, but the transparency is deteriorated.

In the polycarbonate resin of the present invention, if necessary, for example, triphenyl phosphite, tris (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, diphenyl hydrogen phosphite, Irganox 1076 [stearyl-β -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like,
For example, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-
Weathering agents such as 3 ', 5'-di-tert-amylphenyl) benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2-hydroxy-4-octoxybenzophenone, etc. You may add additives, such as a coloring agent, an antistatic agent, a mold release agent, and a lubricant. Further, any method such as injection molding, extrusion molding, and heat press molding is adopted to mold the polycarbonate resin of the present invention, but the method of film formation by the casting method is most suitable for increasing transparency. is there. The polycarbonate resin of the present invention obtained as described above has a high refractive index, low birefringence, and excellent transparency.

[0021]

EXAMPLES The present invention will be further described with reference to the following examples. The parts and% in the examples are parts by weight and% by weight, unless otherwise specified. The specific viscosity, total light transmittance, refractive index and photoelastic coefficient were measured by the following methods.

Specific viscosity: 0.7 g of the polymer was dissolved in 100 ml of methylene chloride and measured at 20 ° C. Total light transmittance: Measured by Σ80 manufactured by Nippon Denshoku Co., Ltd. according to ASTM D-1003. Refractive index: wavelength 59 by Abbe refractometer manufactured by Atago Co., Ltd.
It was measured at 25 ° C. using a D line of 8.3 nm. Photoelastic coefficient (birefringence): 30 mm × 10 mm × 100 μm
Photoelasticity measuring device P manufactured by Riken Keiki Co., Ltd.
It was measured by A-150.

[0023]

Example 1 9,9-bis (4-hydroxyphenyl)
21.5 parts of fluorene, 2.47 parts of bisphenol A,
23.8 parts of 48.5% aqueous sodium hydroxide solution and 36 distilled water
One part was charged into a reactor equipped with a stirrer and dissolved. To this, 162 parts of methylene chloride was added, and the mixed solution was cooled to 20 ° C., and 10.0 parts of phosgene was blown in for 40 minutes. Thereafter, to the reaction solution was added 0.108 parts of p-tert-butylphenol in a solution of methylene chloride, 2.98 parts of a 48.5% aqueous sodium hydroxide solution and 0.05% of triethylamine.
Part of the mixture was added and stirring was continued for 2 hours to complete the reaction. After completion of the reaction, a lower layer methylene chloride solution of polycarbonate was separated from the reaction solution, the solution was washed with an aqueous solution of hydrochloric acid and distilled water, and then methylene chloride was removed by evaporation to obtain a polycarbonate powder. The specific viscosity of the obtained powder was 0.850. This powder was dissolved in methylene chloride to form a film. The total light transmittance of this product is 89%, the refractive index is 1.636, and the photoelastic coefficient is 24 × 1.
It was 0 ^-13 cm ² / dyne.

[0024]

Example 2 9,9-bis (4-hydroxyphenyl)
19.0 parts of fluorene and 4.1 of bisphenol A
A powder was obtained in the same manner as in Example 1 except that 1 part was used. The specific viscosity of this powder was 0.863. When this powder was molded and evaluated in the same manner as in Example 1, the total light transmittance was 89%, the refractive index was 1.631, and the photoelastic coefficient was 30 × 10 ⁻¹³ cm ² / dyne.

[0025]

Example 3 9,9-bis (4-hydroxyphenyl)
12.6 parts of fluorene and 8.2 of bisphenol A
A powder was obtained in the same manner as in Example 1 except that 3 parts were used. The specific viscosity of this powder was 0.755. When this powder was molded and evaluated in the same manner as in Example 1, the total light transmittance was 90%, the refractive index was 1.616, and the photoelastic coefficient was 48 × 10 ^-13 cm ² / dyne.

[0026]

Comparative Example 1 9,9-bis (4-hydroxyphenyl)
Fluorene 2.53 parts and bisphenol A 14.
A powder was obtained in the same manner as in Example 1 except that 8 parts were used. The specific viscosity of this powder was 1.024. When this powder was molded and evaluated in the same manner as in Example 1, the total light transmittance was 90%, the refractive index was 1.592, and the photoelastic coefficient was 74 × 10 ⁻¹³ cm ² / dyne.

[0027]

[Comparative Example 2] Bisphenol A polycarbonate powder having a specific viscosity of 0.451 [Panlite manufactured by Teijin Chemicals Ltd.]
L-1250] was molded and evaluated in the same manner as in Example 1. As a result, the total light transmittance was 90%, the refractive index was 1.589, and the photoelastic coefficient was 83 × 10 ⁻¹³ cm ² / dyne.

[0028]

The polycarbonate resin of the present invention has a high refractive index, a low birefringence and an excellent transparency.
It is extremely useful for various optical applications such as films and disks that require high refractive index, low birefringence and transparency.

Claims (1)

[Claims] 1. The following general formula [1]: [In the formula, R _{1 to} R ₄ are a hydrogen atom, a halogen atom, a phenyl group or an alkyl group having 1 to 3 carbon atoms and may be the same or different. ] And the following general formula [2] [Wherein W is a single bond, an alkylidene group, a cycloalkylidene group, a phenyl group-substituted alkylidene group, a sulfone group, a sulfide group or an oxide group, and R ₅ and R ₆ are a hydrogen atom, a halogen atom, a phenyl group, and a carbon number of 1 ~ 3 alkyl groups, which may be the same or different, and m and n are integers of 1 to 4, respectively. ] The structural unit represented by general formula [1] is 41-95.
Mol% and the photoelastic constant is 50 × 10 ^-13 cm ² / dyne
A high-refractive-index, low-birefringence polycarbonate resin having a specific viscosity of 0.19 or more when 0.7 g is dissolved in 100 ml of methylene chloride and measured at 20 ° C.