JPH0762058B2 - Method for producing heat-resistant high nitrile resin - Google Patents

Description

The present invention relates to a method for producing a high nitrile resin having improved heat resistance (heat distortion temperature).

[Conventional technology]

The rubber-reinforced high nitrile content resin has the gas and vapor barrier properties and solvent resistance inherent in high nitrile resins.
Further, since it is a thermoplastic polymer imparted with impact resistance, it has recently attracted attention as a packaging container material in the fields of foods, agricultural drugs, cosmetics and the like.

Examples of the body surface of such a high nitrile resin include Japanese Patent Publication No. 46-
A high nitrile resin disclosed in Japanese Patent No. 25005, which is obtained by graft-polymerizing a monomer composed of 70% by weight or more of acrylonitrile and 30% by weight or less of unsaturated carboxylic acid ester, to a diene synthetic rubber is mentioned. Such resin is
While it has excellent gas barrier properties and impact resistance and can be molded into any packaging container material by a known molding method, it has a problem that its use is limited because of its low heat distortion temperature.

[Problems to be solved by the invention]

An object of the present invention is to provide a method for producing a high nitrile resin having excellent heat resistance (high heat distortion temperature). That is, a high nitrile resin obtained by graft polymerization, which is conventionally known as a resin having excellent gas barrier property, impact resistance and molding processing method, has excellent heat resistance without deteriorating the above-mentioned characteristics originally possessed. (EN) It is intended to provide a method for producing a high nitrile resin capable of imparting (high heat distortion temperature).

[Means for solving problems]

The present inventors have conducted extensive studies to achieve the above-mentioned object, and by grafting and containing a maleimide-based monomer, it is possible to improve heat resistance without deteriorating the properties originally possessed by a high nitrile resin. Finally, the present invention was reached.

That is, the present invention, in an aqueous medium, in the presence of a polymerization initiator,
(A) 60 to 90% by weight of unsaturated nitrile, (B) 1 to 30% by weight of maleimide monomer, and (C) 5 to 5 monomers copolymerizable with the above (A) and (B). 100 parts by weight of a monomer mixture containing 35% by weight, copolymerization by emulsion polymerization method in the presence of 1-40 parts by weight of a rubber-like polymer containing 50% by weight or more conjugated diene monomer units, Is a method for producing a heat-resistant high nitrile resin.

A feature of the present invention is that a monomer mixture containing an unsaturated nitrile and a maleimide-based monomer is graft-polymerized by an emulsion polymerization method in the presence of a rubbery polymer.

Hereinafter, the present invention will be described in detail.

The heat-resistant high nitrile resin targeted by the present invention is a bulk polymerization, a solution polymerization, any one of the known general polymerization methods including an emulsion or suspension polymerization method, batch polymerization, continuous polymerization, or It can be produced by a polymerization method in which a monomer mixture is intermittently added. However, considering the ease of removing heat of polymerization, the ease of post-treatment, and the like, graft polymerization by an emulsion polymerization method is preferable as a method for producing a high nitrile resin.

The copolymerization reaction of a rubbery polymer and the copolymerization reaction of a high nitrile resin in the presence thereof are used in an aqueous medium, an emulsifier or, if necessary, a dispersant as an auxiliary agent to initiate free radical formation. It can be carried out at any temperature from 0 to 100 ° C. by removing oxygen in the presence of agents and other additives.

As the emulsifier, a higher fatty acid soap such as sodium laurate, an alkylaryl sulfonate such as sodium isopropylbenzenesulfonate, or the like can be used.

Also useful as a polymerization initiator are lauroyl peroxide, organic peroxides such as benzoyl peroxide, azo compounds such as azobisisobutyronitrile,
Examples thereof include water-soluble peroxides such as hydrogen peroxide and potassium persulfate.

The unsaturated nitrile useful in the present invention has the following general formula (2): Embedded image wherein R is hydrogen, a lower alkyl group having 1 to 4 carbon atoms, or halogen. Examples of such compounds include acrylonitrile, α-chloroacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile and the like. The most preferred unsaturated nitrile is acrylonitrile.

The amount of unsaturated nitrile used is 60 to 90% by weight, preferably
65-85% by weight. If the amount added is less than the above range, the gas barrier property becomes poor, and if it is more than the above range, the heat resistance decreases.

The maleimide-based monomer used in the present invention is an essential component of the present invention and has the following general formula (1) (In the formula, R ₁ , R ₂ , and R ₃ each independently represent hydrogen, halogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or an aryl group).

Examples of the maleimide-based monomer include maleimide, N-phenylmaleimide, N-cyclohexylmaleimide, N
Examples thereof include N-substituted maleimides such as -o-methylphenyl maleimide, N-methyl maleimide, N-ethyl maleimide and N-butyl maleimide. These may be used in combination of two or more. The amount of maleimide-based monomer used is 1 to 30.
Weight percent is preferred. If it exceeds 30% by weight, the melt index of the obtained resin is lowered and the processability is deteriorated. Further, if it is less than 1% by weight, the degree of improvement in heat resistance decreases.

Examples of the monomer that can be copolymerized with the unsaturated nitrile and maleimide-based monomer used in the present invention include unsaturated carboxylic acid ester, vinyl aromatic monomer, vinyl ester, vinyl ether, and α-olefin. The amount of these used is preferably 5 to 35% by weight. When the amount exceeds the above range, the amount of unsaturated nitrile is relatively decreased, so that the gas barrier property of the obtained resin is deteriorated.

Examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylates, butyl acrylates, amyl acrylates, hexyl acrylates, methyl methacrylate, ethyl methacrylate, propyl methacrylates, and methacrylic acid. Butylates, amyl methacrylates, hexyl methacrylates, methyl α-chloroacrylate, ethyl α-chloroacrylate and the like, most preferably methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate. Etc.

Examples of the vinyl aromatic monomer include styrene, α-methylstyrene, vinyltoluenes, vinylxylenes and the like. Styrene and α-methylstyrene are preferred.

As α-olefin, isobutylene, 2-methyl-1
-Butene, 2-methyl-1-pentene, 2-methyl-1
-Hexane, 2-methyl-1-heptene, 2-methyl-
1-octene, 2-ethyl-1-butene, 2-propyl-1-pentene and the like can be mentioned. Isobutylene is preferred.

Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ethers, butyl vinyl ethers, methyl isopropenyl ether, ethyl isopropenyl ether, and the like, and most preferred are methyl vinyl ether, ethyl vinyl ether,
Examples include propyl vinyl ethers and butyl vinyl ethers.

Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate and the like. Vinyl acetate is preferred.

The rubber-like polymer used in the present invention is a homopolymer of conjugated diene-based monomers such as butadiene and isoprene, and a monomer copolymerizable with these conjugated diene-based monomers, such as acrylonitrile, styrene, and methyl acrylate. Is a copolymer with at least 50 conjugated diene-based monomer units.
It contains the weight%.

As the conjugated diene-based monomer, 1,3-butadiene, isoprene, chloroprene, bromoprene, cyanoprene, 2,
3-dimethyl butadiene and the like can be mentioned. Of these, butadiene and isoprene are preferable.

The amount of the conjugated diene-based synthetic rubber used is the above-mentioned monomer mixture.
1 to 40 parts by weight, preferably 2-35 parts by weight, relative to 100 parts by weight
Parts by weight. Generally, when the relative proportion of the rubber component in the resin is increased, the impact strength is increased, but the gas barrier property is somewhat lowered, so the amount of rubber should be adjusted so that the physical properties according to the intended purpose are obtained within the above range. You can select it.

The present invention, in the presence of the rubber-like polymer, an unsaturated nitrile, a maleimide-based monomer, and a mixture of a monomer copolymerizable with the unsaturated nitrile and the maleimide-based monomer by an emulsion polymerization method. It is a method of obtaining a heat resistant high nitrile resin by graft copolymerization. According to the present invention, a resin composition in which a copolymer obtained by grafting a part of the monomer mixture onto a rubber-like polymer and a copolymer obtained by copolymerizing a part of the monomer mixture are uniformly mixed. can get.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to Examples. However, "parts" and "%" shown in the examples are based on weight.

Reference Example Production of Conjugated Diene Rubber Latex A monomer mixture consisting of the following components was subjected to emulsion polymerization at 45 ° C. for 15 hours under stirring in an atmosphere from which oxygen was removed using a stainless steel polymerization reactor.

Acrylonitrile 40 parts 1,3-Butadiene 60 parts Fatty acid soap 2.5 parts Azobisisobutyronitrile 0.3 parts t-Dodecyl mercaptan 0.5 parts Water 200 parts Monomer conversion is 90%, the obtained conjugated diene rubber latex The solid content concentration was 30%.

Example 1 A mixture of acrylonitrile, methyl acrylate and a maleimide monomer was emulsion polymerized in the presence of the conjugated diene rubber latex obtained in the above Reference Example. The amounts of main and auxiliary materials used are as follows.

Acrylonitrile 75 parts Methyl acrylate 25 parts Latex of the above reference example 33 parts Maleimide 5 parts Sodium dioctyl sulfosuccinate 1.0 parts Polyvinylpyrrolidone 0.4 parts Potassium persulfate 0.06 parts n-Dodecyl mercaptan 1.0 parts Water 235 parts Polymerization reaction under nitrogen atmosphere It was carried out at 60 ° C. for 8 hours with stirring. The conversion rate of the monomer was 90%. The obtained latex was coagulated with an aqueous solution of aluminum sulfate, washed with water and dried to obtain a powdery polymer.

This polymer was pressure-molded at 170 ° C. and 140 kg / cm ² to prepare a test piece, and the notched Izod impact value (Izod) at 23 ° C. and a load of 3.828 kg was measured according to ASTM D256. Moreover, in order to investigate the processing method of the polymer, the melt indexer
According to TM D1238, outflow rate (MI) at 200 ℃, 12.5kg load
Was measured. Furthermore, in accordance with ASTM D648, heat distortion temperature (HD
T) was measured. The measurement results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 2 Polymerization was carried out in the same manner as in Example 1 except that the amount of maleimide was changed to 10, 20, 30, 40 parts. The polymer obtained was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Examples 5 to 8 and Comparative Example 3 Example 1 was repeated except that 5, 10, 20, 30, and 40 parts of N-phenylmaleimide was used as the maleimide-based monomer. The results are shown in Table 1.

Examples 9 to 11 Example 1 was repeated except that 10 parts each of N-cyclohexylmaleimide, N-methylmaleimide and N-butylmaleimide were used as maleimide-based monomers. The results are shown in Table 1.

[Effect of the Invention] A feature of the present invention is to graft-polymerize a monomer mixture containing an unsaturated nitrile and a maleimide-based monomer in an aqueous medium in the presence of a rubber-like polymer by an emulsion polymerization method.

According to the present invention, excellent heat resistance (high heat distortion temperature) is imparted without deteriorating the excellent gas barrier property, impact resistance and molding processability originally possessed by the high nitrile resin obtained by graft polymerization. can do.

Further, since the graft polymerization is carried out by the emulsion polymerization method, the respective components constituting the obtained resin are chemically bonded. In addition, the components that are not graft-polymerized are mixed together with the chain growth during the copolymerization process, so that the composition is more uniform than the physically mixed blend.

Furthermore, since the polymerization is carried out by an emulsion polymerization method in an aqueous medium, it is easy to remove the heat of polymerization, and additional equipment such as a step of recovering an organic solvent is unnecessary, which is also useful in that it is a simple process. is there.

 ─────────────────────────────────────────────────── --Continued from the front page Judgment panel for referees Chief referee Yoshio Narui Judge Judge Kento Kondo Toshihide Kawakami (56) References JP-A-60-79019 (JP, A) JP-A-57-31914 (JP, JP, A) JP-A-52-129757 (JP, A) JP-A-51-45154 (JP, A) JP-B-45-14549 (JP, B1)

Claims (5)

[Claims] 1. An aqueous medium in the presence of a polymerization initiator,
(A) 60 to 90% by weight of unsaturated nitrile, (B) 1 to 30% by weight of maleimide monomer, and (C) 5 to 5 monomers copolymerizable with the above (A) and (B). 100 parts by weight of a monomer mixture containing 35% by weight, copolymerization by emulsion polymerization method in the presence of 1-40 parts by weight of a rubber-like polymer containing 50% by weight or more conjugated diene monomer units, A method for producing a heat resistant high nitrile resin. 2. The method for producing a heat-resistant high nitrile resin according to claim 1, wherein the unsaturated nitrile is acrylonitrile. 3. The copolymerizable monomer is at least one selected from (meth) acrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms, styrene, α-methylstyrene, isobutylene and vinyl acetate. The method for producing a heat-resistant high nitrile resin according to claim 1, which is a monomer of 4. A maleimide-based monomer is represented by the following general formula (1): (Wherein R ₁ , R ₂ and R ₃ each independently represent hydrogen, halogen, a substituted or unsubstituted alkyl group or aryl group having 1 to 20 carbon atoms) The method for producing a heat-resistant high nitrile resin according to item 1. 5. The method for producing a heat-resistant high nitrile resin according to claim 1, wherein the rubber-like polymer is a butadiene-acrylonitrile copolymer.