JPH09316187A - Method for modifying polycarbonate resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for modifying a polycarbonate resin whereby a resin which does not cause evaporation or bleed out of an ultraviolet absorber and provides excellent ultraviolet-secreening effects is obtd. by using a specific ultraviolet-absorbing substance as a terminal stopper. SOLUTION: Therminal groups represented by formula I (wherein R1 and R2 are each H, a halogen, or a 1-6C alkyl; and R3 is a 1-10C alkyl) are attached to the molecular terminals of a polycarbonate resin formed from a dihydric phenol and phosgene in such an amt. of terminal groups that benzotriazole rings in the terminal groups account for at least 0.1wt.% of the resin. A pref. compd. which is used for giving the terminal group is 2-(2'-hydroxy-5'-β- hydroxyethylphenyl)benzotriazole. A pref. dihydric phenol is represented by formula II (wherein W is a single bond, 0, S, SO, SO2 , CO, or a 1-12C hydrocarbon group; and R4 to R7 are each H, a halogen, or a 1-6C alkyl).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for modifying a polycarbonate resin. More specifically, the present invention relates to a method for producing a modified polycarbonate resin having an excellent UV-cutting effect, which is free from volatilization and bleed-out of the UV absorber during melt extrusion, molding, and use.

[0002]

2. Description of the Related Art Conventionally, as a typical polycarbonate resin, there is known one obtained by reacting 2,2-bis (4-hydroxyphenyl) propane (commonly called bisphenol A) with phosgene. Such polycarbonate resins are widely used in a wide range of fields because of their excellent properties such as transparency, heat resistance and dimensional accuracy. Further, in recent years, it has been widely used for optical applications such as optical discs, lenses and transparent plates by utilizing the excellent optical properties of polycarbonate resins. Particularly in the case of eyeglass lenses, not only fashionability but also safety is demanded, and it is strongly demanded to block ultraviolet rays harmful to the eyes.

Various methods have been proposed in the past for imparting an ultraviolet blocking effect to a polycarbonate resin, and the method of adding and mixing a small amount of an ultraviolet absorber is the most general method. However, in this method, there are problems that the ultraviolet absorbent volatilizes during melt extrusion or molding, the working environment is deteriorated, and it is difficult to obtain the expected ultraviolet blocking effect. Further, when the obtained molded product is used, the ultraviolet absorbent bleeds out, which causes a problem that the surface of the molded product is contaminated. In order to prevent volatilization and bleed-out of the ultraviolet absorber, a method of using an ultraviolet absorber having a relatively large molecular weight or copolymerizing the ultraviolet absorber has been proposed. However, these methods have problems such as insufficient UV blocking effect and large coloring, and no satisfactory method has been proposed yet.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polycarbonate resin having an excellent UV-cutting effect without volatilization or bleed-out of the UV absorber during melt extrusion, molding, or use. is there.

The inventor of the present invention intends to achieve the above object.
As a result of earnest researches on modification of polycarbonate resin, the excellent transparency and moldability of polycarbonate resin can be maintained by using an ultraviolet absorbing substance with a specific structure as an end-stopper when producing polycarbonate resin. At the same time, it has been found that a polycarbonate resin having an excellent ultraviolet blocking effect without volatilization of the ultraviolet absorber and bleed-out can be obtained. The present invention has been completed by further research based on this finding.

[0006]

The present invention provides the following general formula (1) at the end of a polycarbonate resin composed of a dihydric phenol and phosgene.

[0007]

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[0008] [wherein R ₁ and R ₂ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms R ₁ and R
₂ may be the same or different. R ₃ is an alkylene group having 1 to 10 carbon atoms. ] The method for modifying a polycarbonate resin is characterized in that the benzotriazole ring in the terminal group is added to the polycarbonate resin in an amount of at least 0.1% by weight.

Examples of the dihydric phenol constituting the polycarbonate resin to be modified include hydroquinone, resorcin, 4,4'-dihydroxydiphenyl and bis (4
-Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bisphenol A, 2,2-bis (3-methyl-4) -Hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (3-phenyl-4)
-Hydroxyphenyl) propane, 2,2-bis (3-
Isopropyl-4-hydroxyphenyl) propane,
2,2-bis (4-hydroxyphenyl) butane, 2,
2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dibromo-4-)
Hydroxyphenyl) propane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfide, 3,3'-dimethyl-4,4'-dihydroxydiphenyl sulfide, 4, 4'-dihydroxydiphenyl oxide and the like can be mentioned. These may be used alone or in combination of two or more. Among such dihydric phenols, the following general formula (2)

[0010]

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[In the formula, W is a single bond, -O-, -S-, -S.
_{O -, - SO 2 -,} - CO- or a hydrocarbon group having 1 to 12 carbon atoms may be contained aromatic groups, R ₄ ~
R ₇ is a hydrogen atom, a halogen atom or an alkyl group having 1 to 4 carbon atoms, and R _{4 to} R ₇ may be the same or different. ] The dihydric phenol represented by is preferable, and bisphenol A is especially preferable. Also, a small amount of a trifunctional compound may be used as a branching agent, or a part of the dihydric phenol may be replaced with a dicarboxylic acid.

In order to produce the polycarbonate resin of the present invention from the above dihydric phenol and phosgene, an interfacial polycondensation reaction is usually carried out in the presence of an acid binder and a solvent. An alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used as an aqueous solution as the acid binder, and a halogenated hydrocarbon such as methylene chloride or chlorobenzene is used as the solvent. Further, a molecular weight modifier is used, and a catalyst such as a tertiary amine or a quaternary ammonium salt can be used to further accelerate the reaction.
The reaction temperature is usually 0 to 40 ° C, the reaction time is several minutes to 5 hours,
The pH during the reaction is usually preferably maintained at 10 or higher.

In order to impart a terminal group represented by the general formula (1) to the polycarbonate resin, the following general formula (3) is used when the polycarbonate resin is produced.

[0014]

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[In the formula, R _{1 to} R ₃ are the same as those in the general formula (1). ] The compound represented by this is used as a molecular weight regulator. In the formula, hydrogen atoms are particularly preferable as R ₁ and R ₂ , and an alkyl group having 1 to 3 carbon atoms is preferable as the alkyl group. R ₃ is preferably an alkylene group having 1 to 6 carbon atoms. Among them, 2- (2'-hydroxy-5'-β- in which R ₁ and R ₂ are hydrogen atoms and R ₃ is an ethylene group.
Hydroxyethylphenyl) benzotriazole is preferred.

The amount of the compound represented by the general formula (3) used varies depending on the kind of the dihydric phenol used for producing the polycarbonate resin, the intended use of the modified polycarbonate resin obtained, and the like, and can take a wide range. However, the amount of benzotriazole ring in this compound is at least 0.1% by weight, preferably at least 0.15% by weight, based on the modified polycarbonate resin obtained. If the amount is less than 0.1% by weight, it becomes difficult to impart a sufficient ultraviolet ray cutting effect to the polycarbonate resin. The upper limit does not have to be particularly set and may be added to all the terminals, but the ultraviolet blocking effect becomes saturated at about 50 mol% of all terminal groups, and the modified polycarbonate resin obtained as the amount increases Tends to be colored, so it is preferably limited to 50 mol% of all terminal groups. The remaining end groups have other molecular weight regulators such as phenol.
You may add monofunctional phenols, such as phenol, p-tert-butylphenol, p-cumylphenol, and isooctylphenol. The molecular weight of the modified polycarbonate resin thus obtained is not particularly limited, but 0.7 g of the polymer is dissolved in 100 ml of methylene chloride to obtain 2
The specific viscosity of the solution measured at 0 ° C. is preferably 0.05 to 0.5.

The modified polycarbonate resin of the present invention includes
Phosphorus stabilizers can be included and are also preferred. Phosphorous acid ester and phosphoric acid ester are preferable as the phosphorus-based stabilizer. Examples of the phosphite include triphenylphosphite, trisnonylphenylphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecylphosphite,
Trioctyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite,
Monodecyldiphenylphosphite, monooctyldiphenylphosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-te)
rt-Butylphenyl) octylphosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tetrakis (2.
4-di-tert-butylphenyl) -4,4-diphenylenephosphonite and other phosphorous acid triesters, diesters, and monoesters may be mentioned. Of these, trisnonylphenyl phosphite and tris (2,4-di-te
rt-Butylphenyl) phosphite and distearyl pentaerythritol diphosphite are preferred. Examples of the phosphoric acid ester include tributyl phosphate, trimethyl phosphate, tricresyl phosphate, triphenyl phosphate triethyl phosphate, diphenyl cresyl phosphate, tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate, and the like, among which triphenyl phosphate. , Trimethyl phosphate is preferred. These stabilizers may be used alone or in combination of two or more kinds. The phosphorus-based stabilizer is preferably used in the range of 0.0001 to 0.05% by weight based on the modified polycarbonate resin.

The modified polycarbonate resin of the present invention preferably contains a phenolic antioxidant. Examples of phenolic antioxidants include triethylene glycol-bis [3- (3-tert-butyl-
5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,
4,6-tris (3,5-di-tert-butyl-4-
(Hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl Ester, tris (3,5-di-tert-butyl-
4-hydroxybenzyl) isocyanurate, 3,9-
Bis {1,1-dimethyl-2- [β- (3-tert-
Butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane and the like. The preferred addition amount of these antioxidants is 0.0001 to 0.05% by weight based on the modified polycarbonate resin.

Further, in the modified polycarbonate resin of the present invention, in addition to the phosphorus-based stabilizer and the phenol-based antioxidant, other additives such as a light stabilizer and a colorant may be added, if necessary.
Antistatic agents, lubricants, release agents, glass fibers, glass beads, carbon fibers, metal fibers, talc, silica and the like can be added. When the modified polycarbonate resin of the present invention is molded, it can be molded by any method such as an injection molding method, a compression molding method, an extrusion molding method and a solution casting method.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. In the examples, parts and% are parts by weight and% by weight, respectively. (1) Specific viscosity: 0.7 g of the polymer was dissolved in 100 parts of methylene chloride.
The solution was dissolved in ml and measured at 20 ° C. (2) Glass transition temperature; measured by DuPont DSC910. (3) Spectral light transmittance: diameter 40 m obtained by compression molding
m, 3 mm thick test piece, Hitachi spectrophotometer UV-
It was measured by 3600.

Example 1 A thermometer, a stirrer, and a reactor equipped with a dropping funnel were charged with 783.8 parts of ion-exchanged water and 112.7 parts of a 48% sodium hydroxide aqueous solution, and 151.3 parts of bisphenol A and hydro. After dissolving 0.3 parts of sulfite, 457.0 parts of methylene chloride was added, and 71.6 parts of phosgene was blown thereinto under stirring at 23 to 25 ° C. over 45 minutes. After the completion of blowing phosgene, 6.8 parts of 2- (2'-hydroxy-5'-β-hydroxyethylphenyl) benzotriazole as an end-stopping agent (the benzotriazole ring in the end group is 1. Bisphenol A dissolved in 58.0 parts of 48% sodium hydroxide aqueous solution.
2.3 parts was added, and triethylamine as a catalyst was further added.
After adding 46 parts of the mixture and emulsifying the mixture, the mixture was stirred at 25 to 30 ° C. for about 1 hour to complete the reaction. After the reaction was completed, the product was diluted with methylene chloride, washed with water, acidified with hydrochloric acid and washed with water. When the conductivity of the aqueous phase became almost the same as that of ion-exchanged water, methylene chloride was evaporated to give a colorless modified polycarbonate resin. 1
67 parts (yield 94%) were obtained. The polymer had a specific viscosity of 0.444 and a glass transition temperature of 148 ° C. This polymer was extruded at 280 ° C. with an extruder to form pellets, and the obtained pellets were used to obtain test pieces. During that time, no white smoke was observed. The spectral light transmittance of the test piece is 0% at 380 nm or less,
The value at 700 nm was 85%.

[Example 2] 2- (2'-hydroxy-
Example 1 except that the amount of 5′-β-hydroxyethylphenyl) benzotriazole used was 11.8 parts (the amount of benzotriazole ring in the terminal group was 3.1% based on the modified polycarbonate resin). 174 parts (yield 95%) of colorless modified polycarbonate resin were obtained in the same manner as in.
The polymer had a specific viscosity of 0.279 and a glass transition temperature of 148 ° C. Pellets and test pieces were obtained from this polymer in the same manner as in Example 1. During that time, no white smoke was observed. The spectral light transmittance of the test piece was 0% at 380 nm or less and 85% at 700 nm.

[Example 3] 2- (2'-hydroxy-
Example 1 except that the amount of 5′-β-hydroxyethylphenyl) benzotriazole used was 2.5 parts (the amount of benzotriazole ring in the terminal group was 0.7% based on the modified polycarbonate resin). 165 parts (yield 95%) of colorless modified polycarbonate resin were obtained in the same manner as in. This polymer has a specific viscosity of 0.541 and a glass transition temperature of 1.
It was 49 ° C. Pellets and test pieces were obtained from this polymer in the same manner as in Example 1. During that time, no white smoke was observed. The spectral light transmittance of the test piece was 0% at 380 nm or less and 85% at 700 nm.

[Example 4] 1,2 as dihydric phenol
-Bis (4-hydroxyphenyl) cyclohexane 15
Using 1.3 parts, 2- (2'-hydroxy-5'-β-
Colorless in the same manner as in Example 1 except that the amount of hydroxyethylphenyl) benzotriazole used was 1.7 parts (the amount of the benzotriazole ring in the terminal group of the modified polycarbonate resin was 0.5%). The modified polycarbonate resin of 1. was synthesized, washed with water, and a methylene chloride solution of this polymer was cast on a glass substrate and dried to obtain a transparent film. The specific viscosity of this polymer is 1.06
5. The glass transition temperature was 170 ° C. The spectral transmittance of this cast film is 0% at 380 nm or less, 7
00 nm was 90%.

[Comparative Example 1] 2- (2'-hydroxy-
173 parts of a polycarbonate resin containing no ultraviolet absorber in the same manner as in Example 1 except that 3.5 parts of p-tert-butylphenol was used instead of 5′-β-hydroxyethylphenyl) benzotriazole (yield 99%).
I got This polymer has a specific viscosity of 0.405, a glass transition temperature of 148 ° C., and a spectral light transmittance of 380 nm.
Was 78% and 700 nm was 88%.

Comparative Example 2 0.3 part of 2- (2'-hydroxy-5'-β-hydroxyethylphenyl) benzotriazole was added to 100 parts of the polymer synthesized in Comparative Example 1 (2- (2 2'-hydroxy-
5′-β-hydroxyethylphenyl) benzotriazole was added to the benzotriazole ring in an amount of 0.14%, and the mixture was extruded with an extruder in the same manner as in Example 1 to form pellets. Was observed. In addition, the spectral light transmittance is 38
0% or less was 0% and 700 nm was 90%.

[0027]

Industrial Applicability According to the present invention, it is possible to provide a polycarbonate resin having an excellent UV-cutting effect, which is free from volatilization during melt extrusion of an ultraviolet-absorbing substance or during molding and does not bleed out from the surface of a molded article. , The industrial effect it produces is exceptional.

Claims (5)

[Claims] 1. A polycarbonate resin composed of a dihydric phenol and phosgene is added to the terminal of the following general formula (1): [In the formula, R ₁ and R ₂ are a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, and R ₁ and R ₂ may be the same or different. R ₃ is an alkylene group having 1 to 10 carbon atoms. ] The method for modifying a polycarbonate resin, characterized in that the terminal group represented by the formula (3) is added in an amount such that the benzotriazole ring in the terminal group becomes at least 0.1% by weight based on the polycarbonate resin. 2. A compound used for imparting a terminal group represented by the general formula (1) is 2- (2′-hydroxy-).
The method for modifying a polycarbonate resin according to claim 1, which is 5'-β-hydroxyethylphenyl) benzotriazole. 3. A dihydric phenol is represented by the following general formula (2): [In formula, W is a single bond, -O-, -S-, -SO-, -SO.
_2- , -CO- or a hydrocarbon group having 1 to 12 carbon atoms which may contain an aromatic group, and R _{4 to} R ₇ are hydrogen atoms, halogen atoms or alkyl groups having 1 to 6 carbon atoms. And R _{4 to} R ₇ may be the same or different. ]
The method for modifying a polycarbonate resin according to claim 1, which is a dihydric phenol represented by: 4. The dihydric phenol is 2,2-bis (4-
A method for modifying a polycarbonate resin according to claim 1, which is hydroxyphenyl) propane. 5. The modified polycarbonate resin has a molecular weight of 0.16 expressed as a specific viscosity of a solution obtained by dissolving 0.7 g of a polymer in 100 ml of methylene chloride and measuring at 20 ° C.
The method for modifying a polycarbonate resin according to any one of claims 1 to 4, which is 5 or more.