JPH0749474B2 - Method for producing polycarbonate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a polycarbonate resin in which the melted resin has a large fluidity and therefore has a good moldability.

[Prior Art] Generally, polycarbonate is produced by a reaction of an organic dihydroxy compound and phosgene, and is known as an engineering plastic excellent in heat resistance and mechanical strength. In order to obtain the fluidity of the molten resin during molding, it must be molded by heating it to a high temperature close to the decomposition temperature of the polycarbonate resin. Especially when molding thin-walled products or molding intricate shapes, molding often fails because the resin flow is insufficient even at temperatures close to the decomposition temperature of the resin. Brown spots of the decomposed product occur due to overheating of the product, resulting in poor appearance of the molded product.

In order to solve such a situation, as a means for improving the fluidity of the polycarbonate during molding, a method of adding a plasticizer and a method of using a specific molecular weight modifier (Japanese Patent Publication No. 52-50078), Already proposed.

In the method of adding a plasticizer, the fluidity is improved, but vapor of the plasticizer having an offensive odor is generated at the time of molding to impair the working environment, and the vapor of the plasticizer is condensed on the mold surface. There is a drawback that it is transferred to the surface of the molded product and the appearance of the product becomes poor.

On the other hand, the method of using a specific molecular weight modifier is a monofunctional organic compound having a linear aliphatic group having a carbon number in a specific range in a reaction system for producing a polycarbonate to control the molecular weight, and the molecular weight of the polycarbonate. The molecular weight modifier is added to the end of the main chain to improve the fluidity of the polycarbonate. This material has improved fluidity, but has the drawback of reduced heat resistance.

[Problems to be Solved by the Invention] In the present invention, in order to solve the contradictory difficult situation that heat resistance is generally deteriorated when fluidity is increased, the above method of adding a specific molecular weight modifier to the end of the main chain of the polycarbonate. In the above, it is an object of the invention to provide a method for producing a polycarbonate in which only the fluidity is improved while maintaining the heat resistance.

[Means for Solving the Problems] As a result of various studies on the molecular weight regulator used in the production of polycarbonate, the present inventors have conducted polymerization of polycarbonate with a monofunctional fatty acid or acid halide having a branched alkyl group. The present invention has been accomplished by finding that the addition of a molecular weight modifier to the reaction system does not lower the heat resistance and thus improves only the fluidity.

That is, in the present invention, when a polycarbonate is produced by reacting a dihydroxy compound and phosgene in a liquid medium in the presence of a molecular weight regulator, a compound represented by the formula R-COX (where R is 8 to 8 carbon atoms) is used as a molecular weight regulator. 20 branched alkyl groups, X
Is a halogen atom or a hydroxyl group) is used to provide a method for producing a polycarbonate, which is characterized by using a monofunctional organic compound.

As the organic dihydroxy compound used as a raw material of the present invention, any compound can be used as long as it produces a polycarbonate by a reaction with phosgene, and examples thereof include an aromatic dihydroxy compound, an aliphatic dihydroxy compound and an alicyclic dihydroxy compound. Although aromatic dihydroxy compounds such as bisphenol A can be preferably used. In general, since polycarbonate is not crystalline and its physical properties are not deteriorated even if it is a copolymer, a method of adjusting the physical properties of a polymer is commonly used as a copolymer composed of two or more dihydroxy compounds. Also in the present invention, a copolymer using two or more kinds of these organic dihydroxy compounds, for example, an aromatic dihydroxy compound other than the starting aromatic dihydroxy compound or an aliphatic or alicyclic dihydroxy compound is added to the present invention. Polycarbonate can be produced.

Examples of the aromatic dihydroxy compound as a raw material of the polycarbonate of the present invention include bis- (4-hydroxyphenyl) methane and 1,1-bis- (4-hydroxyphenyl)
Ethane, 1,1-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, (hereinafter referred to as "bisphenol A"), 2,2-bis- (4-hydroxy) Phenyl) butane, 2,2-bis-
(4-hydroxyphenyl) pentane, 2,2-bis-
(4-Hydroxyphenyl) isopentane, 2,2-bis- (4-hydroxyphenyl) hexane, 2,2-bis-
(4-hydroxyphenyl) isohexane, 4,4-dihydroxytriphenylmethane, 4,4-dihydroxytetraphenylmethane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, 2,2-bis- (4,4 -Hydroxy-3-methylphenyl) propane, 2,2-bis- (4,4-
Hydroxy-3,5-dimethylphenyl) propane, dihydroxydiphenylether, dihydroxydiphenylsulfone, dihydroxydiphenylsulfide, di (4
Bisphenols such as -hydroxyphenyl) diphenylmethane and di (4-hydroxyphenyl) di (4-methylphenyl) methane, and divalent phenol compounds such as hydroquinone, resorcin, o-methylresorcin, and o-cumylresorcin However, a particularly preferred aromatic diol is bisphenol A.

Examples of the aliphatic dihydroxy compound of the present invention include trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,
Decamethylene glycol, diethylene glycol and the like can be used alone or together with the aromatic dihydroxy compound.

Examples of the alicyclic dihydroxy compound of the present invention include 1,
Hydrogenated products of aromatic rings of the above-mentioned aromatic dihydroxy compounds including 4-dihydroxycyclohexane can be used.

The molecular weight modifier used in the present invention is a fatty acid or acid halide having a branched alkyl group having 8 to 20 carbon atoms, preferably 10 to 18 carbon atoms.

If the carbon number is less than 8, there is almost no improvement in fluidity,
If the carbon number exceeds 20, the heat resistance will decrease.

Examples of the fatty acid or acid halide having such branched alkyl include, for example, trimethylhexanoic acid, triethylhexanoic acid, diethylhexanoic acid, ethylhexanoic acid, methylethylhexanoic acid, trimethylheptanoic acid, triethylheptanoic acid, diethylheptanoic acid. , as hexyldecanoate, for example, valeric acid (C _5), hexanoic acid (C _6), heptanoic acid (C _7), octanoic acid (C _8), nonanoic acid (C _9), decanoic acid (C ₁₀₎ , Undecanoic acid (C ₁₁ ), lauric acid (C ₁₂ ), myristic acid (C ₁₃ ),
A carboxylic acid having a structure having one or more linear or branched alkyl groups having 1 to 6 carbon atoms as a side chain in a linear carboxylic acid such as palmitic acid (C ₁₆ ) or an acid halide thereof can be used. Further, in the present invention, two or more kinds of these molecular weight modifiers may be used in combination.

The polycarbonate of the present invention can be produced by a usual method for producing a polycarbonate, for example, any known method such as an interfacial polymerization method or a pyridine method.

For example, an organic diol dissolved in an alkaline aqueous solution is reacted with phosgene in the presence of an inert organic solvent, a molecular weight modifier is added before or during the reaction, and after the reaction is completed, in the presence of a tertiary amine as a polymerization catalyst. Interfacial polymerization method for obtaining a polycarbonate resin by carrying out interfacial polymerization and pyridine for directly obtaining a polycarbonate resin by dissolving organic diols and a molecular weight modifier in pyridine or a mixed solvent of pyridine and an inert solvent and blowing phosgene into this solution. A polymerization method or the like can be suitably adopted as the polymerization method of the polycarbonate of the present invention.

The obtained resin can be purified by subjecting it to neutralization and washing steps, or by precipitation with a poor solvent such as alcohol or ketone, by a conventional method.

The polycarbonate obtained according to the present invention has a molecular weight regulator having a branched alkyl group of the present invention bound to both ends of almost all polymer molecules, and therefore, the present invention has a terminal group structure composed of the branched alkyl. The present invention provides a method for producing a novel polycarbonate.

The flowability of the molten resin at the time of molding processing of the polycarbonate resin obtained by the present invention, if the molecular weight is the same,
It depends on the structure of the polymer terminal group, that is, the type of branched alkyl group possessed by the molecular weight regulator used during production.

A polycarbonate resin having desired fluidity and heat resistance can be produced by combining various kinds of branched alkyl groups of the molecular weight modifier and the addition amount thereof.

[Effect of the Invention] The polycarbonate resin obtained by the production method of the present invention is
The heat resistance is good, although the degree of improvement in fluidity is equivalent to that of the conventional one produced by adding a molecular weight modifier having a linear alkyl group having 8 to 20 carbon atoms.

As a result, there is an advantage that thin-wall molding and manufacturing of a molded product having a complicated structure are possible, and the molding cycle can be shortened even in the case of an ordinary molded product.

Further, since no plasticizer is used, the working environment is not impaired, and the appearance of the product is not deteriorated, which is advantageous.

[Examples] The present invention will be described in more detail with reference to Examples. Example 1 43.2 g of sodium hydroxide was dissolved in 530 g of water, and 91.2 g of bisphenol A and 0.1 g of hydrosulfite were further dissolved while maintaining the temperature at 20 ° C. did. To this, methylene chloride
While adding 325 g and stirring, 2.37 g of 3,5,5-trimethylhexanoic acid was added, and then 41 g of phosgene was bubbled in over 60 minutes. After the completion of blowing phosgene, stir the mixture vigorously to emulsify the reaction solution, and after emulsification, add 0.1 g of triethylamine to about 1
Stirring was continued for polymerization.

The aqueous layer and the organic layer were separated from this polymerization solution, and the organic layer was neutralized with phosphoric acid. After repeating washing with water until the pH of the washing liquid became neutral, 400 g of isopropanol was added to precipitate a polymer. The precipitate was filtered and vacuum dried at 50 ° C. to obtain a white powder polycarbonate.

Next, this polycarbonate was melted at 300 ° C. and extruded through pores having a diameter of 2 mm to form a transparent strand, which was shredded to obtain a chip-shaped polycarbonate.

The average molecular weight determined from the intrinsic viscosity of a methylene chloride solution of this polymer, the flow value measured using a Koka type flow tester, and the heat distortion temperature measured using a compression molded piece are as shown in Table 1.

Example 2 A chip-shaped polycarbonate was prepared in the same manner as in Example 1 except that 3.84 g of 2-hexyldecanoic acid was used instead of using 3,5,5-trimethylhexanoic acid. Obtained.

Physical properties of this polymer are shown in Table 1.

Example 3 The same treatment as in Example 1 was repeated except that instead of using 3,5,5-trimethylhexanoic acid in Example 1, 2.64 g of 3,5,5-trimethylhexanoic acid chloride was used. Then, a chip-shaped polycarbonate was obtained.

Physical properties of this polymer are shown in Table 1.

Comparative Example 1 43.2 g of sodium hydroxide was dissolved in 530 g of water and 91.2 g of bisphenol A, 2.25 g of paratershariptylphenol and 0.1% of hydrosulfite were added while keeping the temperature at 0 ° C.
g was dissolved, 325 g of methylene chloride was added thereto, and 43.6 g of phosgene was blown thereinto with stirring for 60 minutes. After the completion of blowing phosgene, the reaction solution was vigorously stirred to emulsify, 0.1 g of triethylamine was added after emulsification, and stirring was continued for about 1 hour to polymerize. The aqueous layer and the organic layer were separated from the polymerization solution, and the organic layer was neutralized with phosphoric acid. After repeating washing with water until the pH of the washing liquid became neutral, 400 g of isopropanol was added to precipitate a polymer. The precipitate was filtered and vacuum dried at 50 ° C. to obtain a white powder polycarbonate. This polycarbonate is then melted at 300 ° C and
It was extruded from the pores of mm to form a transparent strand, which was shredded to obtain chip-shaped polycarbonate.

The average molecular weight determined from the intrinsic viscosity of a methylene chloride solution of this polymer, the flow value determined by a Koka type flow tester and the heat distortion temperature measured using a compression molded piece are as shown in Table 1.

Comparative Example 2 91.2 g of bisphenol A was dissolved in a mixed solvent of 100 g of pyridine and 600 g of methylene chloride, and 1.4 g of propionic acid chloride dissolved in 50 g of methylene chloride was added thereto. 40g of phosgene while stirring at a temperature of 20 ℃
Was blown in 90 minutes. After 400 g of methylene chloride was added to dilute the solution, 700 g of 10% hydrochloric acid aqueous solution was added, and the mixture was vigorously stirred for 15 minutes.

The water layer and the organic layer were separated, and the organic layer was repeatedly washed with water until the pH of the washing liquid became neutral. After washing with water, the aqueous layer was again separated with a centrifuge. After adding methanol to the organic layer to precipitate the polymer, a chip-shaped polycarbonate resin is obtained in the same manner as in Comparative Example 1.

The physical properties of this polymer are as shown in Table 1.

Comparative Example 3 91.2 g of bisphenol A was dissolved in a mixed solvent of 100 g of pyridine and 600 g of methylene chloride, and 1.95 g of caproic acid dissolved in 50 g of methylene chloride was added thereto. 2
While maintaining the temperature at 0 ° C., 40 g of phosgene was blown in for 90 minutes while stirring, 400 g of methylene chloride was added to dilute the solution, and 700 g of 10% hydrochloric acid aqueous solution was added, followed by vigorous stirring for 15 minutes. The water layer and the organic layer were separated, and the organic layer was repeatedly washed with water until the pH of the washing liquid became neutral. After washing with water, the aqueous layer was again separated with a centrifuge. After adding methanol to the organic layer to precipitate the polymer, a chip-shaped polycarbonate resin is obtained in the same manner as in Comparative Example 1.

The physical properties of this polymer are as shown in Table 1.

Comparative Example 4 43.2 g of sodium hydroxide was dissolved in 530 g of water, and 91.2 g of bisphenol A and 0.1 g of hydrosulfite were further dissolved while maintaining the temperature at 20 ° C. While stirring 325 g of methylene chloride, 4.13 g of valmitic acid chloride was added, and then 41 g of phosgene was blown in for 60 minutes.

After blowing phosgene, stir vigorously to emulsify the reaction solution,
After the emulsification, 0.1 g of triethylamine was added, and the mixture was stirred for about 1 hour to continue polymerization. Then, the same treatment as in Comparative Example 1 was performed to obtain a chip-shaped polycarbonate. The physical properties of this polymer are as shown in Table 1.

From the results shown in Table 1, the molecular weights of the polycarbonates obtained here are regulated to be almost the same, and when the molecular weight regulator having an alkyl group having less than 8 carbon atoms is used, the heat resistance is high but the fluidity is high. It is found that when palmitic acid chloride having a low C.sub.8 and having a linear alkyl group having 8 to 20 carbon atoms is used as the molecular weight modifier, the fluidity is improved but the heat resistance is significantly reduced.

On the other hand, it is understood that the polycarbonate resin of the present invention using the molecular weight regulator having a branched alkyl group has improved fluidity while maintaining heat resistance.

Claims (1)

[Claims] 1. When a polycarbonate is produced by reacting an organic dihydroxy compound with phosgene in a liquid medium in the presence of a molecular weight regulator, the molecular weight regulator is represented by the formula R—COX (where R is 8 to 8 carbon atoms). 20 branched alkyl groups, X
Is a halogen atom or a hydroxyl group). A method for producing a polycarbonate, comprising using a monofunctional organic compound represented by