JPH075691B2 - Raw material charging method in emulsion polymerization - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a raw material charging method in the production of an impact resistant resin by grafting at least one vinyl monomer onto a diene elastomer. .

[Conventional technology]

As methods for obtaining a graft polymer, methods such as emulsion polymerization method, solution polymerization method, bulk polymerization method and suspension polymerization method are known.

Among them, in the emulsion polymerization method, vinyl monomers, diene elastomers and other additives are continuously added for the purpose of avoiding the collapse of latex due to excessive heat generation due to rapid reaction and controlling the copolymerizability of monomers. A method of charging the polymerization tank in a divided or divided manner is adopted. (For example, JP-A-60-6206
Issue).

[Problems to be Solved by the Invention]

However, when the graft polymer is produced by the above method, there are many kettle scales at the end of the polymerization, resulting in a decrease in productivity and a problem of processing as an industrial waste, and further deterioration in properties during resin processing, and processing. It causes problems such as later appearance deterioration.

An object of the present invention is to provide a raw material charging method at the time of polymerization, which is capable of reducing the above-mentioned problems such as a kettle scale, reducing the amount of industrial waste, and improving productivity.

[Means for solving problems]

The present inventors have earnestly studied a method of adding an emulsifier during polymerization in order to improve productivity by stabilizing a diene elastomer, and have completed the present invention.

That is, in an emulsion polymerization method of producing a graft polymer by copolymerizing at least one monovinyl monomer in the presence of a diene elastomer, a diene elastomer and an emulsifier and other continuous or divided charges, A method for charging raw materials in emulsion polymerization, which comprises separately charging into a polymerization tank from a charging port using independent pipes.

In the present invention, the diene elastomer means a conjugated diene having 4 to 6 carbon atoms, for example, rubbery homopolymers and copolymers of butadiene, isoprene, piperylene and the like, and one or more of these dienes. And other monomers such as acrylonitrile, methacrylonitrile, α
-A copolymer with methylstyrene, styrene, ethyl acrylate, methyl methacrylate and the like.

Preferably, 1,3-butadiene and isoprene are used as the conjugated diene, and acrylonitrile, styrene, methacrylonitrile are used as the monomer for copolymerization.

In particular, the diene elastomer used in the present invention preferably contains at least 50% by weight of a polymerized diene, and its production method may be a method of emulsion polymerization using a usual radical initiator, and there is no particular limitation on its production method. .

Examples of the monovinyl monomer used in the present invention include monomers comprising one or more of aromatic vinyl compounds, unsaturated nitriles, unsaturated carboxylic acid esters, vinyl esters, vinyl ethers, α-olefins and the like. .

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluenes, vinylxylenes, and the like, and preferably styrene.

Examples of the unsaturated nitrile include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, and the like, and acrylonitrile and methacrylonitrile are preferable.

Examples of the unsaturated carboxylic acid ester include esters of acrylic acid or methacrylic acid such as methyl, ethyl, propyl and butyl, preferably methyl acrylate,
They are ethyl acrylate, methyl methacrylate, and ethyl methacrylate.

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

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, with vinyl ethers, ethyl vinyl ethers, propyl vinyl ethers, and butyl vinyl ethers being preferred.

As the α-olefin, isobutene, 2-methyl-1
-Butene, 2-methyl-1-pentene, 2-methyl-1
-Hexene, 2-methyl-1-heptene, 2-methyl-
1-octene, 2-ethyl-1-butene, 2-propyl-1-butene and the like can be mentioned, with preference given to isobutene.

As the emulsifier used in the present invention, anion, nonion, and cationic surfactants, which are generally known animal fats, vegetable fats, semi-synthetic fats, synthetic fats and the like, can be used. Anionic surfactants are preferred.

In the present invention, the other continuous or divided charge means a vinyl monomer, a molecular weight adjusting agent and a pH adjusting agent. The polymerization initiator may be charged continuously or dividedly if necessary.

In the present invention, Japanese Patent Application No. 60-6206 (Japanese Patent Laid-Open No. 61-1668) is used.
No. 13), Japanese Patent Application No. 60-6205, JP-A No. 61-166812, and the polymerization method disclosed in the initial specification is preferably used. In this method, 1 to 40 parts by weight of a diene elastomer is graft-polymerized with at least one kind of vinyl monomer. In order to control the physical properties and molecular weight of the polymer, the diene elastomer, the vinyl monomer, and the molecular weight are adjusted. Agents, emulsifiers, pH regulators, etc. are charged continuously or in divided amounts.

Utilizing this polymerization method, the diene elastomer and the emulsifier and other continuous or divided charges are separately charged into the polymerization tank from the charging port using an independent pipe by the method of the present invention, thereby completing the polymerization. The kettle meal (scale) generated in the polymerization tank at that time is about 1/50 of that of the conventional method of charging from the same charging port, and the post-polymerization process is greatly simplified, and at the same time, the production unit is also reduced. It is remarkably improved. Also, if the scale of kamame (scale) is reduced, the amount of industrial waste treated will be reduced to about 1/50.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples, but it goes without saying that the scope of the present invention is not limited by the Examples.

Production Example (Production of Diene Elastomer) A mixture having the following composition was placed in a polymerization tank equipped with a stirrer, and polymerization was carried out at 50 ° C. for 10 hours under a nitrogen atmosphere.

Acrylonitrile 30 parts by weight 1,3-butadiene 70 parts by weight Fatty acid soap 2.0 parts by weight Azobisisobutyronitrile 0.3 parts by weight t-dodecyl mercaptan 0.5 parts by weight Ion-exchanged water 200 parts by weight The solid content concentration of the obtained diene elastomer is 29.8. %Met.

Example 1 7 parts by weight of the diene elastomer obtained in Production Example and a mixture having the following composition were charged into a polymerization tank equipped with a stirrer, and polymerization was started at 58 ° C. under a nitrogen atmosphere.

Acrylonitrile 14 parts by weight Ethyl methacrylate 6 parts by weight Sodium dioctyl sulfosuccinate 0.2 parts by weight Polyvinylpyrrolidone 0.07 parts by weight Potassium persulfate 0.06 parts by weight Ion-exchanged water 120 parts by weight After adding phosphoric acid to the polymerization system 30 minutes after the start of polymerization, The above compound was continuously charged into the polymerization tank through the charging port for 5 hours to carry out polymerization at a polymerization temperature of 58 ° C. However, the charging port for charging the diene elastomer, sodium dioctylsulfosuccinate and polyvinylpyrrolidone, and the other compounds were charging from separate charging ports.

Acrylonitrile 60 parts by weight Ethyl methacrylate 20 parts by weight Sodium dioctylsulfosuccinate 0.8 parts by weight Polyvinylpyrrolidone 0.32 parts by weight Diene elastomer 26 parts by weight Deionized water 110 parts by weight Pentaerythritol tetrakis (β-mercaptopropionate) 1.65 parts by weight Phosphoric acid 0.38 Parts by weight The amount of kettle meal (scale) after the completion of the polymerization was 0.1 parts by weight.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that the diene elastomer and the emulsifier to be continuously charged were charged into the polymerization tank through the same charging port as other compounds. The kettle meal (scale) after completion of the polymerization was 5.5 parts by weight.

Example 2 Polymerization was started in the same manner as in Example 1 except that 10 parts by weight of the diene elastomer obtained in Production Example and a mixture having the following composition were used.

Acrylonitrile 15 parts by weight Styrene 3 parts by weight Ethyl acrylate 2 parts by weight Sodium dioctyl sulfosuccinate 0.2 parts by weight Polyvinylpyrrolidone 0.07 parts by weight Potassium persulfate 0.06 parts by weight Ion-exchanged water 120 parts by weight Acetic acid was added to the polymerization system 30 minutes after the initiation of the polymerization. Then, the following compounds were continuously charged into the polymerization tank through a charging port over 5 hours to carry out polymerization at a polymerization temperature of 58 ° C. However, the diene elastomer, sodium dioctylsulfosuccinate, polyvinylpyrrolidone, and other compounds were charged through separate charging ports.

Acrylonitrile 50 parts by weight Styrene 10 parts by weight Ethyl acrylate 20 parts by weight Sodium dioctyl sulfosuccinate 0.8 parts by weight Polyvinylpyrrolidone 0.32 parts by weight Diene elastomer 23 parts by weight Ion-exchanged water 110 parts by weight Pentaerythritol tetrakis (β-mercaptopropionate) 1.65 parts by weight Parts acetic acid 0.23 parts by weight After the continuous charging, the polymerization reaction was further carried out for 1 hour. The kettle meal (scale) after the completion of the polymerization was 0.12 parts by weight.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 2 except that the diene elastomer and the emulsifier to be continuously charged were charged into the polymerization tank through the same charging port as other compounds. The kettle meal (scale) after completion of the polymerization was 6.3 parts by weight.

〔The invention's effect〕

By charging the diene elastomer and the emulsifier from a separate charging port from other continuous or divided charging materials, the scale of kamame (scale), which is considered to be due to the collapse of the latex, is greatly reduced, and the basic unit is 8%. As a result, the productivity can be improved and the productivity can be improved. In addition, the amount of industrial waste will be greatly reduced, which will greatly contribute to the industrial world.

 ─────────────────────────────────────────────────── --Continuing the front page Examiner Akira Fujii (56) References JP-A-61-166813 (JP, A) JP-B-46-9474 (JP, B1)

Claims (1)

[Claims] 1. In an emulsion polymerization method for producing a graft polymer by copolymerizing at least one monovinyl monomer in the presence of a diene elastomer, a diene elastomer and an emulsifier and other continuous or divided charges. A method for charging raw materials in emulsion polymerization, characterized in that the substances are separately charged into a polymerization tank from a charging port using independent pipes.