JPS60206810A - Production of copolymer - Google Patents

Abstract

PURPOSE:To obtain a copolymer excellent in transparency, heat resistance, etc. in good efficiency, by copolymerizing alpha-methylstyrene with acrylonitrile in the presence of a bifunctional organic peroxide capable of generating t-butoxy radicals as an initiator. CONSTITUTION:A mixture is formed from 10-80wt% alpha-methylstyrene, 5-50wt% acrylonitrile and 0-70wt% compound selected from among styrene, chlorostyrene, p-methylstyrene, t-butylstyrene and (meth)acrylate esters. This mixture is copolymerized by suspension or bulk polymerization at a temperature of 80- 120 deg.C in the presence of a bifunctional organic peroxide capable of generating t-butoxy radicals and having a 10hr half-life temperature of 60-110 deg.C (e.g., di- t-butyl peroxyhexahydroterephthalate) to obtain the purpose copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention c. 10 to 80% by weight of alpha methylstyrene;
Acrylonitrile A 15-50% by weight, further styrene,
One or more compounds selected from chlorostyrene, paramethylstyrene, t-butylstyrene, acrylic esters, and methacrylic esters are used at a monomer content of 0 to 70% by weight to create a special The present invention relates to a method for producing a copolymer with a high conversion rate, excellent transparency, heat resistance, and strength in a short polymerization time in suspension polymerization or bulk polymerization using a peroxide-based initiator.

Alpha-methylmethylene 4-lene, acrylonitrile, and various substituted styrenes such as styrene, chlorstyrene, paramethylstyrene, and t-butylstyrene that can be copolymerized with these; acrylic acid enethers such as methyl acrylate, ethyl acrylate, and butyl acrylate; methyl methacrylate; In order to obtain a copolymer with sufficient heat resistance for practical use by copolymerizing one or more compounds selected from methacrylic acid esters such as ethyl methacrylate and butyl methacrylate, Alpha methylstyrene is at least 10% by weight of the monomers used.
The content of alpha methylstyrene is preferably 10% by weight or more, preferably 20% by weight or more.
It is necessary to make the copolymer account for 0% by weight or more.

However, based on this viewpoint, conventionally, in order to obtain a copolymer having excellent heat resistance by using a large amount of Al-77 methylstyrene as described above and performing suspension polymerization or bulk polymerization, tertiary glutyl peroxybenzoate, There is a method of using organic peroxides such as tertiary butyl peroxy acetate and ditertiary butyl peroxide as a polymerization initiator, but in methods using these initiators, the polymerization rate is extremely high regardless of the polymerization temperature. It is necessary to use a large amount, and the resulting copolymer has an extremely low degree of polymerization and is therefore of little utility as a molding material. Furthermore, if the amount of initiator is decreased in order to increase the degree of polymerization with these initiators, so-called dead end polymerization will occur.
Although it is not possible to obtain a high conversion rate that is expected industrially, an extremely long polymerization time is required in order to obtain a high conversion rate, resulting in extremely poor productivity. Furthermore, when an organic peroxide such as benzoyl peroxide is used, even if an appropriate polymerization temperature is used, a copolymer with a high conversion rate that can be used industrially cannot be obtained at all.

As described above, in the conventional methods for producing alpha methylstyrene-acrylonitrile copolymers using suspension polymerization or bulk polymerization, a technology capable of producing a copolymer that can be used industrially as a molding material cannot be obtained. Either there was no such thing, or the productivity was extremely poor from an industrial perspective.

As a result of intensive research in view of these points, the present inventors have discovered that alpha methylstyrene-acrylonyl l-lyl-based polymers, which can be produced by suspension polymerization or bulk polymerization, have excellent transparency, heat resistance, and strength with a high conversion rate in short light periods. They discovered a method for producing a polymer and completed the present invention.

That is, the present invention uses alpha methylstyrene 10 to 8
0% by weight, 5-50% by weight of acrylonitrile, 0-70% by weight of one or more compounds selected from styrene, chlorstyrene, paramethylstyrene, t-butylstyrene, acrylic ester, and methacrylic ester. % of monomers, a difunctional organic peroxide with a 10-hour half-life temperature of 60 to 110°C and capable of generating tert-butoxy radicals as an initiator, and a polymerization temperature of Transparency with high conversion rate in short polymerization time by suspension polymerization or bulk polymerization at 80-120℃,
The gist of this paper is a method for producing a copolymer with excellent heat resistance and strength.

The monomer used in the present invention is alpha methylstyrene 10
-80% by weight, 5-50% by weight of acrylonitrile, styrene, chlorstyrene, methylstyrene,
t-butylstyrene, etc.) various substituted styrenes: acrylic esters such as methyl acrylate, ethyl acrylate, butyl acrylate; at least one compound selected from methacrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, etc. 0-7
0% by weight mixture, preferably 20-80% by weight of alpha methylstyrene, acrylonitrile 7210
~40% by weight, and various substituted styrenes such as styrene, chlorstyrene, paramethylstyrene, and t-butylstyrene; acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate; and methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate. At least one selected from acid esters
0 to 70% by weight of species compounds.

Further, the initiator used in the present invention is a difunctional organic peroxide capable of generating t-butoxy radicals, and has a 10-hour half-life temperature of 60 to 110°C. Comparable compounds include di-t-butylperoxyhegisahydroterephthalate, 1,1-di-t-butylperoxyhegisahydroterephthalate,
-Butylperoxy-8,8,5-trimethylcyclohexane, 1,1-di-t-butylperoxine chlorohexane, di-t-butylperoxyazelate, 2゜2-
Examples include di(t-butylperoxy)-butane, 4°4-di-t-butylperoxyvaleric acid-n-glythyl ester, di-t-butylperoxytrimethyl adibate, and the like. Among these, sheet t-butylperoxyhexahydroterephthalate and 1,1-di-t-butylperoxy-3,8,5-)limethylcyclohexane are particularly preferred. The amount used is 0.1 to 2.0% by weight, preferably 0.2 to 1.5% by weight. 0.1% by weight
If the conversion rate is less than that, it may not be possible to obtain an industrially practical conversion rate, or it will take an extremely long time, resulting in extremely poor productivity. If it exceeds 2.0% by weight, a high conversion rate can be obtained in a short time, but the molecular weight will drop significantly and the strength will drop significantly when molded.

As mentioned above, the 10-hour half-life temperature is 60 to 110°C,
By using a difunctional organic peroxide capable of generating t-butoxy radicals, an alpha methylstyrene-acrylonide lyl copolymer can be produced in an extremely short period of time by suspension polymerization or bulk polymerization. The fact that high quality products can be obtained is something that could not have been predicted from conventional technology and knowledge. The mechanism is currently unknown.

As a polymerization method for obtaining the copolymer in the present invention, known suspension polymerization or bulk polymerization is employed. Particularly in the case of suspension polymerization, known dispersants are used in the aqueous medium. Dispersants include organic dispersants such as polyvinyl alcohol, polyvinylpyrrolidone, and methylcellulose, and inorganic dispersants such as tricalcium phosphate, magnesium phosphate, sodium silicate, zinc oxide, and magnesium carbonate. (iii) When anionic surfactants such as dodecylbenzenesulfonic acid sorter and α-olefin sulfonate sodium are used in combination, the dispersion effect becomes significantly better.

Furthermore, when using the initiator in the present invention, it is important to select the polymerization temperature. That is, the polymerization temperature is 80-120℃
is good, and more preferably Vi is 90 to 110°C. 8
If the temperature is less than 0°C, the conversion rate will be extremely low, and if it exceeds 120°C, the molecular weight will decrease, making it difficult to obtain an industrially useful copolymer.

Examples are shown next, and in each table of each example,
The conversion rate of the obtained copolymer is shown in percentage (wt%),
Regarding the properties of the obtained copolymers, the results were obtained for samples molded by injection molding of each copolymer, and the heat distortion temperature was measured as an expression of heat resistance. -6871 method, and the impact strength is also based on the JIS-6871 method. still,
Specific viscosity η5pri The value measured at 30° C. using dimethylformamide as a solvent and 0.2% eluent thereof is shown, and was used as a comparison standard for the degree of polymerization.

Example 1 110 parts by weight of water, 0.24 parts by weight of tricalcium phosphate, 0.0 parts by weight of sodium dodecylbenzenesulfonate, and 0.2 parts by weight of sodium chloride were placed in an autoclave equipped with a stirrer, and the mixture was heated with stirring under stirring. A monomer mixture of 50 parts by weight of alpha methylstyrene, 80 parts by weight of acrylonitrile, and 20 parts by weight of styrene in which 0.3 parts by weight of 1-butylperoxyhexahydroterephthalate was dissolved was introduced into a dazzling light, suspended, and immediately heated to 95°C. After the temperature was raised and polymerization was carried out for 7 hours, the mixture was cooled to 40°C, dehydrated, and dried to obtain a resin (A). Table 1 shows the measured values of the conversion rate, specific viscosity, heat distortion temperature, and impact strength of the resin (A) obtained.

Example 2 In Example 1, instead of using 0.3 parts by weight of the initiator sheet t-butyl peroxyhexahydroterephthalate, 0.0 parts by weight of t, t-butyl barogino 1,8.5-trimethylcyclohexane was used. Using .5 parts by weight, polymerization temperature 9
Resin (B) was obtained in the same manner as in Example 1 except that the temperature was 100°C instead of 5°C.

Table 1 shows the measured values of resin (B).

Example 3 Resin (C) was obtained in the same manner as in Example 1 except that 0.5 parts by weight of sheet t-butylperoxyhexahydroterephthalate was used. Table 1 shows the measured values of resin (C).

Comparative Example 1 A resin (
D) was obtained. The results are shown in Table 1.

Example 4 In Example 1, the amount of di-t-butylperoxyhexahydroterephthalate used was changed to 1.0 parts by weight, and in addition, 1 part by weight of alpha methylstyrene, 10 parts by weight of acrylonitrile, and 60 parts by weight of styrene were added. Polymerization was carried out in the same manner except that

The conversion rate of the obtained resin was 98.2%, and a copolymer with a high conversion rate was obtained in a short polymerization time. Further, the heat distortion temperature was 118°C.

Comparative Example 2 The same procedure as in Example 4 was repeated except that 1.0 parts by weight of benzoyl peroxide was used instead of 1.0 parts by weight of di-t-butylperoxyhexahydroterephthalate and the polymerization temperature was changed to 90°C. Polymerization was carried out. The conversion rate of the obtained resin was extremely low at 42%.

Table 1 *Specific viscosity, heat distortion temperature, and impact strength were not measured because the conversion rate was low and it was impractical.

Note: The initiator used in Example 1 was 0.3 parts by weight of t-butylperoxyhexahydrothyrephthalate, 0.5 parts by weight in Example 3, and 1.1-di- 20.5 parts by weight of t-butylperoxy-3,3°5-trimethylcyclohexa, and 0.3 parts by weight of benzoyl peroxide in Comparative Example 1 were used.

Comparative Example 1 had a low conversion rate and was impractical, so its physical properties were not measured.

Patent applicant Kanebuchi Chemical Industry Co., Ltd. Agent: Patent Attorney Makoto Asano -

Claims (2)

[Claims] (1) Alpha methylstyrene 10-80% by weight,
5 to 50% by weight of acrylonitrile, and 0 to 70% by weight of one or more compounds selected from styrene, chlorostyrene, paramethylstyrene, t-butylstyrene, acrylic ester, and methacrylic ester. Using a certain monomer, the 10-hour half-life temperature is 6
Using a bifunctional organic peroxide that can generate t-butoxy radicals at 0 to 110°C as an initiator,
A method for producing a copolymer, which comprises copolymerizing by suspension polymerization or bulk polymerization at a polymerization temperature of 80 to 120°C. (2) The difunctional organic peroxide is di-t-butyl. Peroxyhexahydroterephthalate or di-t-
A method for producing a copolymer according to claim 1, which is butylperoxy-8,8,5-trimethylcyclohexane.