JPS60248708A - Heat-resistant copolymer - Google Patents

Abstract

PURPOSE:The titled inexpensive copolymer having improved heat resistance, obtained by copolymerizing monomers consisting of methacrylic acid, styrene, methacrylic acid ester, and acrylonitrile in a specific ratio. CONSTITUTION:(A) 5-40pts.wt. methacrylic acid is copolymerized with (B) 95- 60pts.wt. monomer selected from styrene, methacrylic acid ester and acrylonitrile and (C) 0-20pts.wt. monomer (e.g., maleic anhydride, etc.) copolymerizable with it in such a way that total amounts of the components A-C are 100pts.wt., to give the aimed copolymer having 0.01-0.7 specific viscosity [etaSP] (0.3wt% DMF solution). The polymerization is preferably carried out by bulk polymerization method, or bulk and suspension polymerization method with respect to both waste water of polymerization and polymerizability of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copolymer with excellent heat resistance. More specifically, 5 to 40 parts by weight of methacrylic acid, 95 to 60 parts by weight of at least one monomer selected from styrene, methacrylic acid ester, and acrylonitrile, and 0 to 20 parts by weight of a monomer copolymerizable with these. parts by weight (total of monomers: 100 parts by weight).

(Prior Art) Recently, the demand for resins with good heat resistance has been increasing in the fields of automobile parts, electrical parts, and OA equipment parts. Conventionally, engineering plastics such as polycarbonate and polyarylate, and As resin have been used, but the former have drawbacks such as being expensive and the latter having insufficient heat resistance.

(Problems to be Solved by the Invention) The present inventors have conducted extensive research to improve these drawbacks, and as a result, have arrived at the present invention. That is, an object of the present invention is to provide a copolymer that is inexpensive and has excellent heat resistance.

(Means for solving the problems) The present invention will be explained in detail below. The copolymer of the present invention contains 5 to 40 parts by weight of methacrylic acid, at least one selected from styrene, methacrylic acid ester, and acrylonitrile.
It consists of 95 to 60 parts by weight of monomers or more, and 0 to 20 parts by weight of monomers copolymerizable with these monomers. More preferably, 10 to 30 parts by weight of filZ + Jruf, styrene,
It consists of 90 to 70 parts by weight of at least one monomer selected from methacrylic acid ester and acrylonitrile.

If the amount of methacrylic acid is less than 5 parts by weight, the effect of improving heat resistance is small, and if it exceeds 40 parts by weight, molding becomes difficult, which is not preferable. Styrene 1. The ratio of methacrylic acid ester and acrylonitrile used may be arbitrary. From the viewpoint of processing and molding, a system rich in styrene is preferable. In terms of oil resistance and gas barrier properties, yarn rich in acrylonitrile is preferable.

The styrene referred to in the present invention includes styrene and styrene derivatives such as t-butylstyrene, p-methylstyrene, and p-halogenated styrene, and these can be used alone or in combination. Acrylonitrile refers to acrylonitrile and methacrylonitrile, which can be used alone or in combination. The methacrylic ester refers to methacrylic esters such as methyl methacrylate and ethyl methacrylate, and these can be used alone or in combination. In addition, in the present invention,
Monomers copolymerizable with these include maleic anhydride, N
- Refers to known monomers such as maleimide compounds such as phenylmaleimide and N-methylmaleimide, acrylic acid and its esters, and α-methylstyrene. These can also be used alone or in combination.

The copolymer of the present invention can be obtained by a known emulsion polymerization method, suspension polymerization method, bulk polymerization method, or the like using the above-mentioned monomers. Copolymers obtained by emulsion polymerization are difficult to handle due to their small particle size, and require a coagulation process.
Furthermore, the transparency of the molded product is reduced due to the emulsifier remaining in the copolymer particles. Therefore, it is preferable to produce the copolymer by a suspension polymerization method or a bulk polymerization method. In the emulsion polymerization method or the suspension polymerization method, known emulsifiers and dispersants are used.

As the polymerization initiator, a known water-soluble initiator or redox initiator is used in the emulsion polymerization method. Further, in the suspension polymerization method or the bulk polymerization method, a known oil-soluble initiator is used.

In addition, it is advantageous from the viewpoint of polymerization wastewater and the polymerizability of methacrylic acid to adopt a bulk polymerization method in which methacrylic acid is water-soluble, or a bulk/suspension polymerization method in which suspension polymerization is carried out during the bulk polymerization.

The copolymer of the present invention has a specific viscosity [η sp ) of 001 to 0.
．． 7 (0.3% dimethylformamide solution), particularly preferably in the range of 0.03 to 0.5.

In order to adjust the molecular weight of the copolymer, known chain transfer agents such as t-dodecylmercaptan, 2-mercaptoethanol, and thiophenol; known polyfunctional agents such as diallyl phthalate, diethylene glycol diacrylate, and ethylene glycol dimethacrylate are used. Compounds may also be used.

Known lubricants such as behenic acid, ethylene bisstearylamide, stearic acid, and liquid paraffin may be added during the production of the copolymer.

Furthermore, if necessary, known rubbers such as NBE, polybutadiene, and styrene-butadiene copolymers may be added during the production of the copolymer.

The copolymer of the present invention may be used by blending it with the above-mentioned lubricants, known stabilizers, colorants, pigments, flame retardants, and various other resins. Examples of resins to be blended include polyvinyl chloride resins, chlorinated polyvinyl chloride resins, MBS resins, chlorinated polyethylene resins, acrylic rubber resins, NER resins, and known engineering plastics such as polycarbonate and polyarylate. There are resins.

The copolymer of the present invention can be processed and molded using an injection molding machine, a molding machine, or an extrusion molding machine. Furthermore, as a product form, it can be used in the fields of plastic molded products and foam molded products.

(Examples and Effects) Examples of the present invention are shown below, but these do not limit the present invention in any way.

Examples 1 to 11, Comparative Examples 1 to 4 A stainless steel polymerization vessel with an internal volume of 31 mm and a stirring blade.
t-Butylperoxyhexahydroterephthalate (abbreviation HTP), 1,1-dibutylperoxy-3,3,5
-trimethylcyclohexane (abbreviation DBTO), 1,1
'-Azobinucyclohexanecarbonitrile (AB
CC), methacrylic acid, nutylene, methyl methacrylate, and acrylonitrile were charged and polymerized for 3 hours at 95'C, followed by 200 parts of ion-exchanged water in which 0.5 parts of partially saponified polyvinyl acetate was dissolved. was added, and polymerization was further carried out at 95°C for 6 hours. Then +1
Heat treatment was carried out at 5'C for 4 hours. After dehydration, 150
'C for 1 hour. Then, the conversion rate was calculated from the weight of the copolymer.

Next, test pieces were made from this copolymer using an injection molding machine, and the Vicat softening temperature ('C) under a load of 5 kq/cm2 was measured. The results are shown in Table-1. Table 1 also lists the Vicat softening temperature measured in the same manner as above for a commercially available AS resin and polymethyl methacrylate as a comparative example.

Rice 1 Tyril 769 (commercial product of 'AS resin) Rice 2 Acryvet MF (commercial product of polymethyl methacrylate resin) Rice 3 The sample was brittle and could not be taken out as a sheet.

Table 1 shows that the 40 mark indicates that a commercially available resin was used.If the methacrylic acid content is less than 5 parts, the effect of improving heat resistance is small;
It can be seen that when ζ is increased from 0 parts, the processability becomes worse. It is also seen that conventional resins have low r# thermal properties.

Patent applicant Kanebuchi Chemical Industry Co., Ltd. Representative Patent Attorney Makoto Asano

Claims (1)

[Claims] 1. 5 to 40 parts by weight of methacrylic acid, 95 to 60 parts by weight of at least one monomer selected from styrene, methacrylic acid ester, and hyacrylonitrile, and a monomer copolymerizable with these. 0 to 20 parts by weight (total of monomers: 1
00 parts by weight), the specific viscosity [ηsp) is 001 to 0.
, 7 (0.5% dimethylformamide solution). 2. The heat-resistant copolymer according to claim 1, which is obtained by a suspension polymerization method or a bulk polymerization method. 3. During polymerization, switching from bulk polymerization to suspension polymerization
A heat-resistant copolymer according to claim 1 obtained by a suspension polymerization method.