KR890003537B1 - The method of polymerization thermerplastic in suspension pr massive by mma acrylonitril and stylene - Google Patents

Abstract

A thermoplastic resin having an excellent transparency, high surface hardness and weatherability is prepd. by the suspension polymn. of 5- 35 wt.% MMA, 45-80 wt.% styrene and 5-35 wt.% acrylonitrile. The suspension polymn. of the three monomers is carried out by reacting in a mixed soln. of pure water and cellosize at 70-115≰C for 8 hrs, and by adding an antioxidant.

Description

Process for preparing thermoplastic resins by suspension and bulk suspension polymerization by MMA, acrylonitrile and styrene

The present invention relates to a method for producing a thermoplastic resin having high yield by suspension polymerization or superphase suspension polymerization with three components of MMA, acrylonitrile and styrene.

U.S. Patent 4056671 and Japanese Patent No. 49-37836 and the like disclose SAN resin which is a copolymer of styrene and acrylonitrile and MS resin which is a styrene and MMA copolymer.

SAN resins have poor thermal stability and surface hardness, and MS resins have drawbacks of chemical resistance.

According to Japanese Patent Application Laid-Open No. 58-217544, there is a method of raising a copolymer of acrylonitrile and MMA with a copolymer of styrene and acrylonitrile to a melting temperature and then mixing them, but it is difficult to have uniformity of physical properties. According to Korean Patent Application No. 80-1645, a thermoplastic resin polymerized by emulsion polymerization of α-methylstyrene, MMA and acrylonitrile is shown.

In the present invention, styrene was used instead of α-methylstyrene, and the polymerization method was subjected to suspension polymerization or superphase suspension polymerization. MMC polymers have high optical properties, weather resistance and high surface strength, and absorbability has a weak chemical resistance.

Copolymers of acrylonitrile and styrene are transparent, have excellent chemical resistance and economical efficiency, but sometimes they require excellent transparency, surface hardness, and weather resistance. Thus, polymerizing three components of MMA, acrylonitrile, and styrene may be used. The present invention was developed to improve.

In view of the polymerization effect of the three components in the present invention, the more the styrene is added, the slower the polymerization rate, but the dimensional stability of the molded article is excellent, and the weight ranges from 45 to 80%. As the amount of acrylonitrile increases, the polymerization rate increases, the dimensional stability decreases, and the heat resistance increases. Therefore, in order to maintain the balance of physical properties, the range is 5-35%. As the amount of methyl methacrylate increases, the polymerization rate becomes faster and the polymerization system becomes unstable. Therefore, it is in the range of 5-35%. This resin can be mixed with ABS, and when used alone, it is a transparent product and is used in molded articles requiring chemical resistance, weather resistance and high tensile resistance. As the polymerization catalyst, a low temperature catalyst and a high temperature catalyst were used in combination.

TABLE 1

Suspension Polymerization (Value Wt%)

In the polymerization method of Table 1), pure water and cellosize were first mixed and dissolved at 60 ° C. for 20 minutes. Add all remaining treatment compounds and extract the air in the reactor with nitrogen and fill the pressure to prevent air from being introduced. 2 hours at 70-75 ℃, 3 hours at 80-85 ℃, 3 hours at 115 ℃ After the temperature was lowered to 90 ° C., an antioxidant was added and terminated. Resin whose polymerization rate is 99.9% can be obtained.

In Table 1, the reaction rate is faster when the amount of AN and M is increased than styrene, and increasing the amount of catalyst increases the fluidity of the resin, lower molecular weight, lowers the physical properties, and the color is not good. In addition, increasing the reaction inhibitor mercaptan increases the fluidity, but the reaction rate is slowed down and many unreacted substances are used to find an appropriate amount.

TABLE 2

Lump suspension polymerization

In Table 2), the superphase polymerization is carried out by putting the whole treated compound into a reactor, extracting air with nitrogen gas, filling the pressure to prevent air from entering, and then performing polymerization at 75 ° C. for 1 hour and at 80-85 ° C. for 4 hours. Obtain the same characteristics as 3).

TABLE 3

Viscosity and Solid Content According to Polymerization Time

As shown in Table 3), when the viscosity is 6000-8000CP and the solid content is 40-45%, the polymerization is stopped and transferred to the suspension polymerization reactor. After extracting air with nitrogen gas from the suspension polymerization reactor, polymerization is completed for 2 hours at 70-75 ° C, 3 hours 30 minutes at 80-85 ° C, and 3 hours at 115 ° C. Lower the temperature to 90 ° C. and add antioxidant.

The effect of the monomer on the polymerization in the bulk suspension method is as shown in the suspension polymerization, and in suspension polymerization, it is difficult to control the molecular weight due to the high expression in the suspension polymerization, but the reaction is carried out by the suspension polymerization method after the 40-45% block polymerization at low temperature. Therefore, the physical properties can be uniform.

TABLE 4

Property comparison table

Tin: SAN: Styrene acryonitrile

MS: Methylmetacrylate styerne

AN: Acrylonitryl

MMA: Methyl methacrylate

Physical property test method of table 4) iszod impact strength (ASTD D-256), tensile strength (SATM D-638), elongation (ASTM D-638), flexural strength (ASTM D-790), fluidity (ASTM D-1238) ) And hardness (ASTM D-785).

This resin can be mixed with ABS resin, and because it has excellent transparency, surface strength, tensile strength and chemical resistance, it is applied to general injection molded products.

The resin according to the present invention has high surface hardness, features weather resistance and chemical resistance, and has good compatibility with other resins.

Claims (3)

MMA (Methylmethacylate), styrene (Styrene) and acrylonitrile (Acrylonitle), and a method of producing a high yield of thermoplastic synthetic resin by suspension polymerization and bulk suspension polymerization, when the suspension polymerization and bulk polymerization The above method, characterized in that the monomer is treated in the range of 45-80 Wt% of styrene, 5-35 Wt% of acrylonitrile, and 5-35 Wt% of MMA. The method of claim 1, wherein the suspension polymerization is dissolved by mixing pure water and cellosize (Cellosize), and then adding a treating compound such as styrene, acrylate, MMA to the reaction tank, and performing a polymerization reaction ( 70-75 ° C., 2 hours, 80-85 ° C., 3 hours, 115 ° C., 3 hours) by lowering the temperature to terminate the polymerization reaction by adding an antioxidant. The method of claim 1, wherein the bulk suspension polymerization is carried out by placing the entire processing compound into the reactor to extract the air with nitrogen gas to maintain the pressure and then polymerized (75 ℃ 1 hour, 80-85 ℃ 4 hours) viscosity 6000-8000Cp solid When the content is 40-45 Wt%, the polymerization is stopped and polymerized in a suspension polymerization reactor (70-75 ° C 2 hours, 80-85 ° C 3 hours 30 minutes, 115 ° C 3 hours) to terminate the reaction. Way.