KR0180827B1 - Method for manufacturing branched polycarbonate - Google Patents

Abstract

The present invention relates to a branched polycarbonate manufacturing method used as a container and a sheet material, and a biphasic polymerization reaction of a branching agent and a molecular weight modifier in an organic solvent methylene chloride in which dihydric phenols are added to an aqueous alkali solution to make an aqueous solution of a divalent phenol salt and phosgene gas is injected. In the preparation of branched polycarbonate, 0.1 to 1.5 mol% of 2,2'-bis- (3-phenylhydroxy-4-hydroxyphenyl)-(4-hydroxyphenyl) -propane was used as the branching agent. The polycarbonate resin obtained in this way has a strength characteristic and can be widely used in industrial resins such as electrical parts, machine parts, and containers.

Description

Process for producing branched polycarbonate

The present invention relates to a process for producing branched polycarbonates used as raw materials for bottles and sheets.

Polycarbonate resins are widely used as industrial resins such as electrical parts, mechanical parts and containers because they have excellent strength, particularly impact resistance and transparency.

However, linear polycarbonate resins exhibit almost the behavior of Newtonian Fluid upon melting, and their viscosity does not depend on shear rate. In addition, due to the poor melt elasticity and melt strength, it is possible to perform extrusion molding using polycarbonate, especially when blow molding using an extrusion molding machine. It's hard to make a hand.

In order to solve this difficulty, (1) a method of mixing two types of polycarbonates having different molecular weights, and (2) a method of using branched polycarbonates have been introduced. A method of making a branched polycarbonate is known by first adding a phosgene gas into a dihydric phenol and a polyfuntional compound, and then controlling the molecular weight with a monohydric phenol, which is a molecular weight modifier. However, this method is not preferred because of its low reactivity.

Therefore, a method of preparing polycarbonate oligomer having n = 5 to 15 and then reacting polyhydric phenol under amine catalysts has been proposed, but it is also difficult to control the reactivity and the reaction is adjusted to pH = 3 to 6 when phosgene gas is injected. The dihydric phenols tend to precipitate, making it very difficult to complete the reaction. Therefore, there are limitations to the reactors that can be used, and tubular reactors cannot be used.

The polycarbonate oligomer used in the present invention is prepared by adding an aqueous alkali solution to the dihydric phenols to form a dihydric phenol salt solution, followed by stirring with methylene chloride (MC, Methylene chloride), an organic solvent injected with phosgene gas.

The dihydric phenols used at this time usually use the following type of molecule.

Wherein R ₁ , R ₂ , R ₃ and R ₄ are hydrogen, phenyl, a halogen element, an alkyl group corresponding to C _{1 to} C ₃ , and R ⁵ is an alkyl group corresponding to C ₀ to C ₅ , -O-,- S-, -SO _2- , -CO- and the like.

Examples of typical dihydric phenols are as follows.

2,2-bis (4-hydroxyphenol) -propane (aka Bisphenol A), 1,1-bis (4-hydroxyphenol) -cyclohexane, 4,4-dihydroxydiphenol, 2,4- Bis (4-hydroxyphenol) -2-methyl-butane, α, α'-bis (4-hydroxyphenol) -p-diisopropylbenzene, 2,2-bis (3-methyl-4-hydroxy Phenol) -propane, 2,2-bis (3-chloro-4-hydroxyphenol) -propane, bis (3,5-dimethyl-4-hydroxyphenyl) -methane, 2,2-bis (3,5 -Dimethyl-4-hydroxyphenyl) -propane, bis (4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, 2,4-bis (3,5-dimethyl- 4-hydroxyphenyl) -2-methanebutane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -cyclohexane, α, α'-bis (3,5-dimethyl-4-hydroxy Oxyphenyl) -p-diisopropylbenzene, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) -propane, and 2,2-bis (3,5-dibromo-4-hydroxy Oxyphenyl) -propane and the like.

Especially dihydric phenols which are frequently used among them are 2,2-bis (4-hydroxyphenyl) -propane (Bisphenol A), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) -propane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) -propane, 1,1-bis (4-hydroxyphenyl) -cyclohexane, and the like. These dihydric phenols can be used individually or in combination with each other.

The degree of polymerization of the polycarbonate oligomer, that is, the molecular weight of the polycarbonate oligomer can be adjusted to a desired level using a molecular weight modifier such as phenol, p-tert-butyl phenol, isopropyl phenol, where n number is usually 20 or It is smaller than that and shows a better effect when n = 2 to 10.

In addition, the branching agent should contain at least three or more of the following functional groups. That is, a hydroxyl group (-OH), carboxyl group (-COOH), amino group (-NH _2), acid halide (-COCI), formyl group (-CHO) or the like.

Typical examples of branching agents having three or more functional groups are as follows.

Mellitic acid, trimellitic acid, trimellitic acid chloride, trimellitic acid anhydride, pyromellitic acid, resorcyclic acid ], Resorcinaldehyde, trimellitiltrichloride, trihydroxyflavone derivatives, ie 2,4,4-trimethyl-2,4-7-trihydroxyflavone, phloroglucin (Phloroglucin) etc. are mentioned.

The present invention is to prepare a branched polycarbonate by interfacial polymerization of a branching agent and a molecular weight control agent in an organic solvent methylene chloride in which dihydric phenols are added to an aqueous alkali solution to form an aqueous solution of a divalent phenol salt and injected with phosgene gas. 2'-bis (3-phenylhydroxy-4-hydroxyphenyl)-(4-hydroxyphenyl) -propane, and the amount thereof is 0.1 to 1.5 mol%. will be.

In the present invention, the end portion of the polycarbonate oligomer is in the form of chloroformate and is a branching agent containing three or more functional groups. Hydroxyphenyl)-(4-hydroxyphenyl) -propane is used, and the amount is 0.1-1.5 mol%. If the amount is less than 0.1 mol% there is a problem that the branching effect disappears, if it exceeds 1.5 mol% there is a problem that gelatin occurs. In addition, as the phase transfer catalyst in the reaction, triethylamine [(CH ₃ CH ₂ ) ₃ N], tripropylamine [(CH ₃ CH ₂ CH ₂ ) ₃ N], triisopropylamine {[(CH ₃ ) ₂ CH] ₃ N}, and the like. Although there are various reaction conditions in the reaction of the polycarbonate oligomer with the branching agent, the reaction temperature is generally 5 to 40 ° C., more preferably 10 to 30 ° C. The reaction time is usually 10 minutes to 3 hours, more preferably 20 minutes to 1 hour 30 minutes.

The material obtained in the reaction with the branching agent of the polycarbonate oligomer is subjected to the interfacial polycondensation reaction under an aqueous alkali solution (aqueous water ratio of 15 to 20 ± 1%) and a catalyst of amines, and the dihydric phenols used herein are those mentioned above. One typical example is bisphenol A. Trifuntional compounds, which are used as branching agents, also use many of the aforementioned substances.

The interfacial polycondensation reaction is usually performed at a stirring speed of 250 to 500 rpm for 10 to 40 ° C. for about 1 hour and 30 minutes. More preferably, the reaction is performed at 25 ° C. and 500 rpm stirring speed for about 30 minutes. Branched polycarbonates are made.

The branched polycarbonate synthesized in the present invention has a molecular weight of 20,000 to 35,000 and is well soluble in a solvent for dissolving ordinary linear polycarbonate.

In the present invention, there is no side reaction between the reaction of the trivalent or higher multifunctional substance and the dihydric phenol, and the reactivity is very large. In addition, the branched polycarbonate made according to the method of the present invention compared to the existing polycarbonate shows good melting properties, and the dependence of the melt viscosity on the shear rate is very large. One of the advantages of this branched polycarbonate is its high Barus Effect, low deflection, and another great strength.

Thus, the branched polycarbonates made according to the method presented in the present invention are well suited for extrusion molding, in particular for brow molding using an extrusion molding machine, so that high quality sheets, containers and other molded articles can be produced.

The present invention will be described in more detail based on Examples and Comparative Examples as follows.

Example 1

115 g of 2,2-bis (4-hydroxyphenol) -propane (aka bisphenol A), 41.33 g of caustic soda and 647.5 mL of pure water are mixed to form a BPA-Na solution, and carbonyl dichloride (388.5 mL of methylene chloride solvent) 59.9 g of CDC) gas was collected, put together in a 2 L cylinder reactor, and stirred for 5 to 10 minutes to obtain an oligomer having a molecular weight of about 1,000. Subsequently, 0.1205 g of caustic soda and 0.2604 g of 2,2'-bis (3-phenylhydroxy-4-hydroxyphenyl)-(4-hydroxyphenyl) -propane dissolved in 10 mL of pure water were added to the cylinder reactor in two stages. 1.892 g of a molecular weight regulator para-t-butyl alcohol and 0.0346 g of triethylamine as a catalyst were added and reacted at a stirring speed of 500 rpm for 30 minutes to produce an oligomer having a molecular weight of 2,000 to 3,000. Thereafter, the hard layer and the middle layer were separated, and 160 mL of methylene chloride was added to the middle layer, 16 g of caustic soda, 12 mL of pure water, and 0.0069 g of triethylamine were added. The mixture was stirred at a stirring speed of 500 rpm for about 1 hour, followed by 0.0796 g of triethylamine. Add more stirring for 30 minutes to 2 hours while adding the reaction is complete.

When the reaction is complete, stirring is stopped and the heavy solution is diluted with two solvents, pure water and methylene chloride. The washing is continuously washed with alkali, acid, and pure water, and the granulation of branched polycarbonate can be obtained by slowly dropping the finished heavy liquid into a solvent mixed with acetone and pure water at a ratio of 0.5 to 1: 1. After drying for 4 hours at 100 ℃, 2 hours at 140 ℃, it is shown in Table 1 by measuring the physical properties.

EXAMPLES 2-7

In the same manner as in Example 1, but the content of the branching agent as shown in Table 1, the physical properties are shown in Table 1.

[Comparative Examples 1 to 4]

In the same manner as in Example 1, but the content of the branching agent as shown in Table 1, the physical properties are shown in Table 1.

※ In case of Comparative Example 4, the amount of branching agent is high, resulting in gelation.

※ MIR measurement was performed according to ASTM D1238 using a weight of 2.16 kg and 21.6 kg at 260 ° C.

Claims (1)

To prepare a branched polycarbonate by interfacial polymerization of a branching agent and a molecular weight control agent to an organic solvent methylene chloride containing divalent phenols in an aqueous alkali solution, and to an aqueous solution of a divalent phenol salt injected with phosgene gas. 0.1-1.5 mol% of '-bis- (3-phenylhydroxy-4-hydroxyphenyl)-(4-hydroxyphenyl) -propane is added.