JPH0628871B2 - Method for producing molded article having excellent optical properties - Google Patents

Description

The present invention relates to a method for producing a molded article having excellent optical properties,
More specifically, it relates to a method for producing a molded product having excellent transparency and small optical distortion.

[Conventional technology]

The resin molded product used for optical recording / reproduction needs to be transparent and have a small optical distortion. Especially in optical discs that are optical information recording materials using digital signals, such as digital audio discs, digital video discs, and optical discs for reading and writing information, the requirement for transparency is extremely strict. The actual strain is required to be 5 × 10 ⁻⁵ or less in terms of birefringence in an actual molded product. Also,
This type of disk is also required to have no warp and excellent heat resistance.

In order to industrially produce such a molded product, it is advantageous to use a polycarbonate resin having excellent transparency, dimensional stability, heat resistance and the like, and injection-mold this to obtain a molded product.
In particular, in order to obtain a molded product with a small optical distortion, a polycarbonate resin having a specific chemical structure is used, and at the time of injection molding, the fluidity of the resin is improved so that an optical defect caused by the flow of the molten resin is caused. It is necessary to suppress uniform generation.

[Problems to be solved by the invention]

However, if the temperature of the molten resin is increased to improve the fluidity of the resin, the decomposition of the resin causes coloration such as yellowing, which causes various problems such as impairing the transparency of the resulting molded article. Has not reached.

[Means for solving problems]

In view of the above points, the present inventors have conducted extensive studies on a method of producing a molded article having excellent transparency and small optical distortion, and as a result, contain a phosphite ester, a carbonate bond structural unit and a molecular weight. The polycarbonate resin specified in is excellent in melt fluidity and heat stability, and when injection molding is performed under specific conditions using this resin,
The inventors have found that a molded product having good transparency and small optical strain can be produced, and thus the present invention has been accomplished.

[Structure of Invention]

The present invention relates to a carbonate bond structural unit (a component) in which a unit constituting a carbonate bond has a group represented by the following general formula (I) and / or a carbonate bond structural unit having a group represented by the following general formula (II). 0.005 to 0.5% by weight of a phosphite ester in a polycarbonate resin having an average molecular weight of 9,500 to 22,000 consisting of (B component) and optionally a carbonate bond constitutional unit (C component) having a group represented by the following general formula (III): % Of the composition is injection-molded at a resin temperature of 300 to 400 ° C. and a mold temperature of 50 to 150 ° C., which is a method for producing a molded article having excellent optical characteristics.

General formula (I) (In the formula, X and Y are selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group or an aralkyl group, and at least one of X and Y is an aryl group or an aralkyl group.) General formula ( II) (In the formula, A, B, Z, and W are hydrogen atoms or 1 to 6 carbon atoms.
And an at least one of A and B is an alkyl group having 1 to 6 carbon atoms. ) General formula (III) (In the formula, E is Is a divalent group represented by, wherein F and G represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and D represents an alkylene group having 4 to 6 carbon atoms. ) Hereinafter, the present invention will be described in detail.

The carbonate bond in the present invention is obtained by reacting an alcoholic hydroxyl group or a phenolic hydroxyl group with, for example, phosgene. The term "carbonate bond constitutional unit" refers to a divalent group interposed between such carbonate bonds.

The polycarbonate resin used in the present invention includes a carbonate bond structural unit (A component) having a group represented by the general formula (I) and / or a carbonate bond structural unit (B having a group represented by the general formula (II). component)
And a carbonate-bonding structural unit (C component) having a group represented by the general formula (III) as required.

The polycarbonate containing the carbonate-bonding structural unit (component A) having the group represented by the general formula (I) can provide the group represented by the general formula (I). For example, it can be obtained by reacting one or more bisphenol-based compounds represented by the following general formula (I ′) with phosgene and polymerizing them.

General formula (I ') (However, in the formula, X and Y have the same meaning as in the general formula (I).) Examples of the bisphenol compound represented by the general formula (I ′) include bis (4-hydroxyphenyl). ) Phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) dibenzylmethane etc. are mentioned. (Such bisphenol-based compounds will be referred to below) as component A bisphenol. ) A polycarbonate containing a polycarbonate-bonding structural unit (component B) having a group represented by the general formula (II) is
For example, it can be obtained by reacting one or more bisphenol compounds represented by the following general formula (II ') with phosgene and polymerizing, which can provide the group represented by the above general formula (II).

General formula (II ′) (However, in the formula, A, B, Z, and W have the same meanings as in the general formula (II).) Examples of the bisphenol compound represented by the general formula (II ′) include bis (4 -Hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy) -3-ethylphenyl) propane, 2,2-bis (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis (4-hydroxy-3-sec butylphenyl)
Propane etc. are mentioned. (Such a bisphenol compound is hereinafter referred to as a bisphenol for component B.) Furthermore, a carbonate-bonding structural unit (component C) having a group represented by the general formula (III), which is optionally used in the present invention. The polycarbonate containing a compound can be obtained by reacting one or more bisphenol compounds represented by the following general formula (III ′) with phosgene and polymerizing, for example, a group capable of providing the group represented by the above general formula (III). it can.

General formula (III ′) (However, E in the formula has the same meaning as in the general formula (III).) Examples of the bisphenol compound represented by the general formula (III ′) include bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane or bisphenol A, 2,2- Bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 2,2-bis (4-hydroxy) Phenyl) hexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) Such as cyclohexane . (Such a bisphenol compound is hereinafter referred to as a bisphenol for component C.) In the present invention, first, a carbonate-bonding structural unit having a group represented by the general formula (I) (hereinafter referred to as component A) and / or A carbonate bond structural unit having a group represented by the general formula (II) (hereinafter referred to as B component) and, if necessary, a carbonate bond structural unit having a group represented by the general formula (III) (hereinafter referred to as C component). A polycarbonate resin having the above is prepared. As the method, the bisphenol for the component A or the bisphenol for the component B is independently reacted with phosgene to polymerize, bisphenol for the component A and bisphenol for the component B, and optionally bisphenol for the component C. Examples thereof include a method of copolymerizing a phenol and a method of copolymerizing a bisphenol for component A or a bisphenol for component B with a bisphenol for component C. Also, bisphenol for component A, bisphenol for component B, and bisphenol for component C are each reacted with phosgene to obtain respective polycarbonates, and then these polycarbonates may be mixed so as to satisfy the requirements of the present invention. Good. Also,
Copolymerized polycarbonates from two or more of the bisphenols for components A, B and C and polycarbonates from bisphenols containing the remaining components may be mixed to meet the requirements of the invention.

For polymerization, methylene chloride, 1,2-dichloromethane and the like, an inert solvent such as bisphenol compound and an aqueous alkaline solution or an acid acceptor such as pyridine,
Phosgene may be introduced into this and reacted. When an alkaline aqueous solution is used as the acid acceptor, the reaction rate is increased by using a tertiary amine such as trimethylamine or triethylamine or a quaternary ammonium compound such as tetrabutylammonium chloride or benzyltributylammonium bromide as a catalyst. Also, if necessary,
A monovalent phenol such as phenol or p-tert-butylphenol is allowed to coexist as a molecular weight modifier. The reaction temperature is 1 to 100 ° C. The catalyst may be added from the beginning, or it may be used in any method such as by adding it in the middle of the reaction, that is, after the oligomer is formed and carrying out the polymerizing reaction in the presence of the catalyst.

The method for copolymerizing the bisphenol for the component A and / or B and the bisphenol for the component C, which is optionally used, is as follows: (a) by allowing them to exist in the reaction system from the beginning and simultaneously reacting with phosgene. Polymerize, (b) Partly react with phosgene to carry out a certain amount of reaction, then add the remaining component bisphenol to polymerize, (c) Separately react with phosgene to form an oligomer,
Then, any method such as mixing them and further reacting them to polymerize can be adopted.

As a method of mixing separately polymerized,
After mixing each powder or granules, extruder,
Any method such as a method of mixing in a molten state with a kneader or a kneading roll, a solution blending method, or the like can be used.

A component of the polycarbonate resin used in the present invention, B
The contents of the component and the C component are 0 to 100% by weight of the A component and 100 to 0% of the B component in all the carbonate bond constitutional units.
%, C component is 0 to 99% by weight, preferably 0 to 90
% By weight.

The average molecular weight of the polycarbonate resin used in the present invention is 9,500 to 22,000. The average molecular weight referred to here is 2 g using a solution of 6.0 g of polymer in methylene chloride.
It is a value obtained from ηsp measured at 0 ° C. by the following equations (1) and (2).

ηsp / c = [η] (1 + K′ηsp) …… (1) [η] = KM ^α ……………… (2) C polymer concentration in the formula g / [η] intrinsic viscosity, K ′ = 0.28 K 1.23 × 10 ⁻⁵ , α = 0.83 M Average molecular weight If the average molecular weight is too high, it is necessary to perform the molding at a resin temperature of more than 400 ° C. in order to produce a molded product with little optical strain. Decomposition of the resin cannot be avoided at such a high temperature, and there are inconveniences such as the occurrence of silver streaks on the surface of the molded product and coloration. On the other hand, if the average molecular weight is too low, it is possible to obtain a molded product with less optical strain, but the strength of the resin is low, the molded product is easily damaged when released from the mold, and a molded product is obtained. However, the mechanical strength is small.

Next, as the phosphite used in the present invention, a diester or triester of phosphorous acid and an alcohol acid or a phenol is preferably used, and among them, a compound represented by the following general formula (IV) is preferable.

General formula (IV) (In the formula, R ¹ and R ² are an alkyl group having 4 to 18 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ³ is a hydrogen atom, an alkyl group having 4 to 18 carbon atoms or 6 to 2 carbon atoms.
It is an aryl group of 0. As R ¹ and R ² in the general formula (IV), a butyl group, a hexyl group, an octyl group, a 2-ethylhexyl group,
Examples thereof include alkyl groups such as nonyl group, decyl group, dodecyl group, octadecyl group, ventaerythrityl group and cyclohexyl group, and aryl groups such as phenyl group, toluyl group and nonylphenyl group.

Examples of R ³ include a hydrogen atom, the above alkyl group or the above aryl group.

Specific examples of such phosphite include tributyl phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, tristearyl phosphite, triphenyl phosphite, tricresyl phosphite, tris (nonyl phenyl) phosphite, 2-ethylhexyldiphenylphosphite, decyldiphenylphenylphosphite, phenyldi-2-ethylhexylphosphite, phenyldidecylphosphite, tricyclohexylphosphite, distearylpentaerythritylphosphite, diphenylpentaerythritylphosphite, etc. Is mentioned.

The content of the phosphite ester is 0.005 to 0.5% by weight, preferably 0.01 to 0.2% by weight, based on the polycarbonate resin. If the amount of phosphite is too small, it is not possible to suppress the coloring and the deterioration of transparency due to the decomposition of the resin. On the other hand, if the amount is too large, decomposition of the phosphite itself can be seen, which causes inconvenience such as silver streak.

As a method for containing a phosphite ester in a polycarbonate resin, similar to the method for preparing an ordinary resin composition, (a) a method of dry blending both (b) melt-kneading the blend using an extruder or the like. Method (c) Any method such as a method of preparing master pellets having a high phosphite content and mixing them with a polycarbonate resin can be used.

Further, in the present invention, when the polycarbonate resin composition is injection-molded to produce a molded article having excellent optical properties, the resin temperature is 300 to 400 ° C. and the mold temperature is 50 to 150 ° C. To do. If the resin temperature is too high, decomposition of the resin is unavoidable, which causes coloration, silver streaks and the like, resulting in poor transparency. On the other hand, if the resin temperature is too low, it becomes impossible to obtain a molded product having a small optical strain even if the above-mentioned polycarbonate resin, which hardly causes optical strain, is used.

The mold temperature is 50 to 150 ° C., preferably 60 to 1
45 ° C. If the mold temperature is too high, the deformation at the time of mold release becomes large, and it becomes impossible to obtain a molded product with small warpage. On the contrary, if it is too low, a molded product with small optical distortion cannot be obtained.

〔Example〕

Hereinafter, a specific method for producing the polycarbonate resin used in the present invention will be described as a production example, and a method for producing a disk using the obtained polycarbonate resin will be illustrated as an example.

All "parts" indicating the amounts of the following components are "parts by weight". Also, the measured values of physical properties are values measured by the following methods.

(B) Birefringence From the center of the molded 1.2 mm thick disk with a diameter of 130 mm
Phase difference due to birefringence at 3.0 cm and 5.5 cm positions (hereinafter Δ
n _3.0 and Δn _5.5 ). The phase difference due to birefringence was measured with a polarizing microscope manufactured by Nippon Kogaku Co., Ltd.

(B) Warp amount The same disk as above was measured using a flattester FT-7 manufactured by NIDEK.

(C) Melt fluidity 280 ° C, shear rate 10 ³ s by Koka type flow tester
The apparent melt viscosity η _α at ec ^-1 was measured and used as a measure of melt fluidity.

The compositions and average molecular weights of the polycarbonate resins produced in Production Examples 1 to 3 and Comparative Production Examples 1 and 2 are shown in Table 1 below. In addition, the results of Examples and Comparative Examples conducted using these polycarbonate resins are shown in Table 2 and Table 2 below.
3 shows.

Production Example 1 (a) Production of oligomer 1,1-bis (4-hydroxyphenyl) -1-phenylethane 100 parts Sodium hydroxide 40 parts Water 600 parts Methylene chloride 375 parts The above mixture was charged into a reactor equipped with a stirrer at 800 rpm. It was stirred. Blow 57 parts of phosgene into this for 1 hour,
Interfacial polymerization was performed. After completion of the reaction, only the methylene chloride solution containing the polycarbonate oligomer was collected. The analysis results of the methylene chloride solution of the obtained oligomer are as follows.

Oligomer concentration 22.5% by weight (Note 1) Terminal chloroformate group concentration 0.42N (Note 2) Terminal phenolic hydroxyl group concentration 0.020N (Note 3) Note 1) Measured after evaporation to dryness.

2) The aniline hydrochloride obtained by reacting with aniline
Neutralization titration with 0.2N aqueous sodium hydroxide solution.

3) Colorimetric determination of color development at 546 nm when dissolved in titanium tetrachloride and acetic acid solution.

The oligomer solution obtained by the above method is hereinafter abbreviated as oligomer solution-A.

(B) Production of Polycarbonate Oligomer Solution-A 140 parts p-tert-butylphenol 1.9 parts Methylene chloride 80 parts The above mixture was charged into a reactor equipped with a stirrer and stirred at 550 rpm. Further, an aqueous solution having the following composition, that is, 80 parts of a 7.3 wt% aqueous solution of sodium hydroxide and 1 part of a 2 wt% aqueous solution of triethylamino was added, and interfacial polymerization was carried out for 3 hours. The reaction mixture was separated, and the methylene chloride solution containing the polycarbonate resin was washed with water, an aqueous hydrochloric acid solution and then water, and finally the methylene chloride was evaporated to take out the resin. The average molecular weight of this resin was 11,200.

Production Example 2 (a) Production of Oligomer 16.6% aqueous solution of bisphenol A sodium salt prepared by dissolving bisphenol A in aqueous sodium hydroxide solution 100 parts p-tert-butyl phenol 0.23 part methylene chloride 40 parts phosgene 7 parts above The mixture of composition was quantitatively supplied to the pipe reactor for interfacial polymerization.

The reaction mixture was separated, and only the methylene chloride solution containing the polycarbonate oligomer was collected.

The analysis results of the methylene chloride solution of the obtained oligomer are as follows.

Oligomer concentration 24.5% by weight Terminal chloroformate group concentration 1.3 N Terminal phenolic hydroxyl group concentration 0.3 N The oligomer solution obtained by the above method is abbreviated as oligomer solution-B below.

(B) Production of Polycarbonate Oligomer solution-A 208 parts Oligomer solution-B 54 parts Methylene chloride 87 parts p-Tertiary butylphenol 1.46 parts were charged into a reactor equipped with a stirrer and stirred at 550 rpm. Further, an aqueous solution having the following composition was charged and interfacial polymerization was carried out for 2 hours.

Water 48 parts Sodium hydroxide 25% by weight aqueous solution 39 parts Triethylamine 2% by weight aqueous solution 1.1 parts After washing by the same formulation as in Production Example 1, the resin taken out had an average molecular weight of 13.500.

The results of NMR analysis showed that the amount of the bisphenol A-derived carbonate bond constituent units was 20.5% by weight based on the total carbonate bond constituent units.

Production Example 3 Oligomer Solution-B 370 parts p-tert-butylphenol 1.0 part Methylene chloride 300 parts The above mixture was charged into a reactor equipped with a stirrer and stirred at 550 rpm. Further, an aqueous solution having the following composition, that is, a 17 wt% aqueous solution of sodium salt of 2,2-bis (4-hydroxy-3-methylphenyl) propane
200 parts 25% by weight aqueous solution of sodium hydroxide 20 parts 2 parts by weight 2% by weight aqueous solution of triethylamine were added and interfacial polymerization was carried out for about 1.5 hours, the reaction mixture was separated, and a methylene chloride solution containing a polycarbonate resin was added to water and hydrochloric acid. The resin was removed by washing with an aqueous solution and then with water and finally evaporating the methylene chloride.

The average molecular weight of this resin was 17,000, and the copolymerized 2,2-bis (4-hydroxy-
The amount of the bond constitutional unit of the carbonate derived from 3-methylphenyl) propane is 3 with respect to the total carbonate bond constitutional unit.
It was 0.5% by weight.

Comparative Production Example 1 In Production Example 3, p-tertiary butylphenol 1.
The same operation was performed except that 0 part was not used to obtain a polycarbonate resin. The average molecular weight of this resin is 2
3,000, which is copolymerized from the NMR analysis results
The amount of carbonate-bonded structural units derived from 2,2-bis (4-hydroxy-3-methylphenyl) propane was 30.8% by weight based on all carbonate-bonded structural units.

Comparative Production Example 2 In (b) of Production Example 1 of polycarbonate resin, p-
A polycarbonate resin was obtained by the same procedure except that the tert-butylphenol was changed to 2.5 parts. The average molecular weight of this resin was 7,800.

Examples 1 to 3 and Comparative Examples 1 to 5 Polycarbonate resin flakes having an average molecular weight of 11,200 produced in Production Example 1 were mixed with the phosphite ester shown in Table 2 below in an amount shown in Table 2 to obtain a 40 mmφ extruder. Using 2
Melt-knead at 80 ° C and extrude into pellets.
A polycarbonate resin pellet containing phosphite having an average molecular weight shown in was obtained.

These pellets were injected into an injection molding machine (M-140A manufactured by Meiki Co., Ltd.)
At the resin temperature and mold temperature shown in Table-2,
It was formed into a disk with a diameter of 1.2 mm and a diameter of 130 mm.

The retardation and the amount of warpage due to the birefringence of the obtained disk are as shown in Table-2. Example 1 as shown in Table-2
In Nos. 3 to 3, a molded product having a small optical distortion could be obtained. On the other hand, silver streak occurred when no phosphite was contained as shown in Comparative Example 1 or when the resin temperature was too high as shown in Comparative Example 2. Further, when the resin temperature was too low as shown in Comparative Example 3 or when the mold temperature was too low as shown in Comparative Example 4, a molded product with small optical strain could not be obtained. Further, as shown in Comparative Example 5, when the mold temperature was too high, the warp amount was large.

Examples 4 to 6 and Comparative Examples 6 to 7 Polycarbonate resins prepared in Production Examples 2 to 3 and Comparative Production Examples 1 to 2 were mixed with tridecyl phosphite in the amounts shown in Table 3 below to obtain Example 1. Do the same operation,
I got a disk.

The retardation and the amount of warpage due to the birefringence of the obtained disk are as shown in Table-3.

As shown in Table 3, in Examples 4 to 6, moldings having a small optical strain could be obtained. On the other hand, as shown in Comparative Example 6, if the molecular weight of the resin was too high, a molded product with small optical strain could not be obtained. Further, as shown in Comparative Example 7, if the molecular weight of the resin was too low, cracking occurred during molding and a satisfactory molded product could not be obtained.

[Effects of the Invention] As described above, according to the method of the present invention, a molded article having excellent transparency, small birefringence, small warpage and sufficient strength and heat resistance can be produced with a good yield.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location B29L 11:00 4F 17:00 4F (72) Inventor Masahiro Narui 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Address Sanryo Kasei Kogyo Co., Ltd. (72) Inventor Isao Ikuhara 1000 Kamoshida-cho, Midori-ku, Yokohama, Kanagawa Sanryo Kasei Co., Ltd.

Claims (2)

[Claims] 1. A carbonate bond constitutional unit (a component) in which a unit constituting a carbonate bond has a group represented by the following general formula (I) and / or a carbonate bond constitution having a group represented by the following general formula (II). 0.005 to 0.5 of a phosphite ester is added to a polycarbonate resin having an average molecular weight of 9,500 to 22,000 consisting of a unit (component B) and optionally a carbonate bond constitutional unit (component C) having a group represented by the following general formula (III). The composition containing wt%,
A method for producing a molded article having excellent optical properties, characterized by performing injection molding at a resin temperature of 300 to 400 ° C and a mold temperature of 50 to 150 ° C. General formula (I) (In the formula, X and Y are selected from a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group or an aralkyl group, and at least one of X and Y is an aryl group or an aralkyl group.) General formula ( II) (In the formula, A, B, Z, and W are hydrogen atoms or 1 to 6 carbon atoms.
And an at least one of A and B is an alkyl group having 1 to 6 carbon atoms. ) General formula (III) (In the formula, E is Is a divalent group represented by, wherein F and G represent hydrogen or an alkyl group having 1 to 6 carbon atoms, and D represents an alkylene group having 4 to 6 carbon atoms. ) 2. A phosphite is represented by the following general formula (IV): (In the formula, R ¹ and R ² are an alkyl group having 4 to 18 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ³ is a hydrogen atom, an alkyl group having 4 to 18 carbon atoms or 6 to 2 carbon atoms.
It is an aryl group of 0. ) The method according to claim 1, which is a compound represented by the formula: