JPS6357604A - Production of polymer excellent in resistance to corrosion by metal - Google Patents

Abstract

PURPOSE:To obtain the title polymer excellent in resistance to corrosion by metal and free from adverse effects such as odor, hue and toxicity, by emulsion- polymerizing a specified monomer with a carboxylic acid emulsifier and/or a nonionic emulsifier and a terpene compound. CONSTITUTION:100pts.wt. at least one monomer selected from among a conjugated diene monomer (a), an alpha,beta-unsaturated nitrile monomer (b), an aromatic vinyl monomer (c), an alkyl ester (d) of an alpha,beta-ethylenically unsaturated carboxylic acid and an alpha,beta-ethylenically unsaturated carboxylic acid (e), preferably, mixture comprising 100-45wt% component (a) and/or component (d), 0-55wt% component (b), 0-55wt% component (c) and 0-30wt% component (e) is emulsion-polymerized with 0.1-20.0pts.wt. carboxylic acid emulsifier and/or nonionic emulsifier and 0.5-15.0pts.wt. terpene compound (e.g., terpinolene) as an MW modifier at 0-70 deg.C in the presence of a polymerization initiator and a short-stop.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to molecules! Production of a polymer using a terpene compound as a regulator and a carboxylic acid emulsifier and/or a nonionic emulsifier as an emulsifier, which has excellent metal corrosion resistance and is particularly suitable for use in rubber magnets. Regarding the method.

[Conventional technology]

Conventionally, as a method for producing polymers by emulsion polymerization method,
It is known that mercaptan compounds, dialkylxanthogen disulfides, terpene compounds, and halogen compounds such as carbon tetrachloride are used as molecular weight modifiers, but in emulsion polymerization of synthetic rubber, Mooney viscosity can be easily controlled and processability is improved. Normal dodecyl mercaptan and tertiary dodecyl mercaptan, which have good properties, are often used. Further, various types of anionic or nonionic emulsifiers such as carboxylic acid or sulfonic acid are used as the emulsifier.

[Problem that the invention seeks to solve]

However, with a sulfur atom as a molecular weight regulator,
Using mercaptan compounds, conjugated diene monomers, α,
β-unsaturated nitrile monomer, aromatic vinyl monomer, α,
A polymer obtained by emulsion polymerization of one or more monomers selected from β-ethylenically unsaturated carboxylic acid alkyl esters and α,β-ethylenically unsaturated carboxylic acids in the presence of various emulsifiers. For example, in the application of rubber magnets, when the rubber magnet and metal such as copper, copper alloy, silver, silver alloy, etc. are in contact or adjacent at a close distance, the contact surface between the rubber magnet and the metal or the rubber magnet Chemical reactions cause discoloration and corrosion on surrounding metal surfaces such as copper, copper alloys, silver, and silver alloys. As a result, for example, when metals such as copper, copper alloys, silver, and silver alloys are used for conductive members, there is a problem that the conductivity deteriorates due to discoloration or corrosion.

Furthermore, even if a molecular weight regulator of a terpene compound that does not have a sulfur atom is used, the conjugated diene monomer obtained by emulsion polymerization in the presence of an emulsifier that has a sulfur atom, such as a sulfonic acid emulsifier, Body, α.

β-unsaturated nitrile monomer, aromatic vinyl monomer, α,
For the same reason, polymers made of one or more monomers selected from β-ethylenically unsaturated carboxylic acid alkyl esters and α,β-ethylenically unsaturated carboxylic acids also cause a decrease in conductivity. There were some problems.

In addition, when such polymers are processed using metal processing machines (e.g., presses, rolls, calendars, Nigoo, Banbury, extruders), discoloration in the processing machine, mold contamination,
There is a problem that metal corrosion occurs, but in order to solve this problem, the metals such as copper, copper alloy, silver, and silver alloy that make up the rubber magnet were surface-treated in advance by methods such as plating or painting. . However, in the case of articles with intricate structures, it is often extremely difficult to prevent discoloration, mold contamination, and metal corrosion even with the above-mentioned surface treatments.

In order to improve this drawback, the inventors of the present invention have made extensive research and found that a terpene compound is used as a molecular weight regulator, and a carboxylic acid emulsifier and/or a nonionic emulsifier is used as an emulsifier. We have discovered the surprising fact that by using the polymer obtained by this method, discoloration and corrosion on the surface of metals such as copper, copper alloys, silver, and silver alloys can be significantly prevented, and the crosslinked physical properties do not deteriorate. The present invention was achieved based on this.

[Means to solve the problem]

That is, the present invention uses a conjugated diene monomer, α,
β-unsaturated nitrile monomer, aromatic vinyl monomer,
Using one or more monomers selected from α, β-ethylenically unsaturated carboxylic acid alkyl esters and α, β-ethylenically unsaturated carboxylic acids, as an emulsifier, a carboxylic acid emulsifier and/or a nonionic Using a system emulsifier,
The present invention also provides a method for producing a polymer having excellent metal corrosion resistance, which is characterized by carrying out emulsion polymerization using a terpene compound as a molecular weight regulator.

Conjugated diene monomers as monomer components constituting the polymer of the present invention include 1,3-butadiene, isoprene, chlorobrene, 1,3-pentadiene, hexadiene, etc., but other monomers may also be used. Because of the ease of copolymerization with
1,3-Butadiene or isoprene is preferred. As a monomer component constituting the polymer of the present invention, examples of the α,β-unsaturated nitrile monomer include acrylonitrile and methacrylonitrile. Examples of the aromatic vinyl monomer as a monomer component constituting the polymer of the present invention include styrene, α-methylstyrene, vinyltoluene, etc., and styrene is usually used.

As the α,β-unsaturated carboxylic acid alkyl ester monomer constituting the polymer of the present invention, methyl (
Examples include meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, and 2-ethylhexyl acrylate. Further, examples of the α,β-ethylenically unsaturated carboxylic acid that is a monomer component constituting the polymer of the present invention include acrylic acid, methacrylic acid, itaconic acid, and fumaric acid.

The proportion of these monomers used is preferably 100 to 45% by weight of the conjugated diene monomer and/or α,β-ethylenically unsaturated carboxylic acid alkyl ester, based on the total monomer components; α.

The content is 0 to 55% by weight of β-unsaturated nitrile monomer, 0 to 55% by weight of aromatic vinyl monomer, and 0 to 30% by weight of α,β-ethylenically unsaturated carboxylic acid monomer. Particularly preferably, a combination of a conjugated diene monomer and an α,β-unsaturated nitrile monomer or a combination of a conjugated diene monomer and an aromatic vinyl monomer can be used.

The glass transition temperature of the polymer obtained in the present invention is preferably 0°C or lower, particularly preferably -10°C or lower. The glass transition temperature was measured using a differential scanning calorimeter (in addition,
When natural rubber was measured as a standard substance, it was -74°C).

Examples of the terpene compounds used as the molecular weight regulator of the present invention include terpinene, dipentene, t-terpinene, α-terpinene, α-pinene, β-pinene, myrcene, etc. is preferred. If necessary, such terpenes can be used alone or in a mixture of two or more.
The amount of molecular weight regulator used is based on 100 parts by weight of monomer.
0°5 to 15.0 parts by weight, preferably 1.5 to 8.0 parts by weight
Parts by weight. If the amount of this molecular weight regulator is less than 0.5 parts by weight, the effect as a molecular weight regulator will be significantly inferior, and if it exceeds 15.0 parts by weight, the polymerization rate will be slow and the Mooney viscosity of the polymer will be low. This is undesirable in terms of poor productivity in molding and increased costs.

In addition, nonionic emulsifiers preferably exhibit significant surface activity at low concentrations and do not ionize in aqueous solutions. Specifically, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene Fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene propylene block polymer, alkylsulfinyl alcohol,
Examples include fatty acid monoglycerides.

The amount of emulsifier used is 0.00 parts by weight per 100 parts by weight of the monomer.
1 to 20.0 parts by weight can be used, preferably 2.0 to 6 parts by weight.
．． It is 0 parts by weight. If the amount of the emulsifier is less than 0.1 part by weight, polymerization stability will be poor, and if it exceeds 20.0 parts by weight, a large amount of the emulsifier will remain as an impurity in the polymer, which is not preferable.

Polymerization initiators used in the present invention include organic peroxides such as benzoyl peroxide, cumene hydroperoxide, paramenthane hydroperoxide, and lauroyl peroxide, diazo compounds represented by azobisisobutyronitrile, and potassium persulfate. Inorganic compounds, such as organic compounds and redox catalysts typified by combinations of iron sulfate, etc., are used. Each monomer, a polymerization initiator, a molecular weight regulator, and other polymerization agents may be added in their entirety at the start of the reaction, or may be added in arbitrary portions or continuously after the start of the reaction.

Examples of polymerization terminators that can be used in the present invention include hydroxylamine and 2,5-dimethylhydroquinone, and sodium dimethyldithiocarbamate, hydroxyamine sulfate, and the like having a sulfur atom are not preferred.

Polymerization is usually carried out at 0 to 70°C, preferably 5 to 50°C, in a reactor from which oxygen has been removed, but operating conditions such as temperature and stirring can be arbitrarily changed during the reaction. The polymerization method can be either a continuous method or a batch method. The coagulation operation is carried out after adding a suitable anti-aging agent to the obtained polymer latex.

As the coagulant, metal compounds such as sodium chloride, calcium chloride, tin chloride, magnesium chloride, etc. can be used.

Alternatively, as another method, it is possible to coagulate without using a coagulant by adding an anti-aging agent to the polymer latex and heating it to a temperature equal to or higher than the clouding point of the nonionic emulsifier. In either method, it is necessary to solidify the polymer so that no components that would adversely affect metal corrosion resistance remain in the polymer.

The polymers of the present invention contain conventional rubber compounding agents such as carbon black and other reinforcing agents, fillers, extender oils, stearic acid, zinc white, antiaging agents, vulcanization accelerators, and crosslinking or vulcanizing agents. After molding and processing, it can be heat pressed and used for various industrial materials such as rubber magnets, sealing materials, hoses, rolls, oil-resistant packing, printing blankets, and materials related to food, medical equipment, etc. , especially useful as rubber magnets.

In addition, in the application of rubber magnets, the polymer produced by the method of the present invention is used as a binder, and various magnetic materials such as ferrite and compounding agents, such as various processing aids and anti-aging agents, are added to the polymer and cross-linked. Alternatively, it can be provided by non-crosslinked molding. Furthermore, if necessary, it can also be provided in a method other than the above.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

In the examples, "parts" and "%" mean parts by weight and % by weight unless otherwise specified.

Emulsion polymerization was carried out at a temperature of lO<0>C using the monomers and polymerization agents shown below in an autoclave with an internal volume of 2 (l).

Emulsion polymerization Respi Butadiene 30 parts acrylonitrile 70 water
220 Disproportionated Rosin Acid Potassium Salt
4.0 Terpinolene 2.
0 ferrous sulfate 0.005 paramenthane high F Roberoxy F
0002 When the polymerization conversion rate reached 60%, the polymerization reaction was stopped by adding 0.2 parts of hydroxylamine per 100 parts of monomer. The latex produced was then heated, and unreacted monomers were removed by steam distillation, after which 1 part of an antiaging agent (octylated diphenylamine) was added per 100 parts of the produced copolymer, and an aqueous calcium chloride solution was added. The mixture was solidified into crumb-like form. After washing the produced crumb with water, it was dried in a hot air dryer at 100°C to obtain a copolymer.

Of the composition of the produced polymer, the acrylonitrile component was calculated from the total nitrogen content in the obtained polymer using a nitrogen analyzer. The composition of the polymer of Example 1 was: Butashev 50%, acrylonitrile 50%, Mooney viscosity ML, 4 (100°C) 90, in order to conduct corrosion tests of this polymer on copper plates or silver-cadmium plywood. ,
The polymer obtained above was press-molded and
Each metal plate with a thickness of 2fi, which had been thoroughly polished and degreased on the 0th order, which had been cut into 10 cubes to form an aggregate sample, was cut into 3×3 pieces. 300mj of the above 110X10X10 polymer sample! A cylindrical glass pedestal with a height of 3 parts and a height of 1 m x 4 a.phi. was inserted around it, and each metal plate sample was placed on top of the cylindrical glass pedestal. After leaving the specimen bottle in a gear open at 80° C. for 48 hours, each metal plate sample was taken out, and the degree of corrosion was visually ticked and evaluated on a four-grade scale. The results are shown in Table 1.

Further, this polymer sample was kneaded according to the formulation shown below, and then crosslinked at 160°C for 20 minutes, and the physical properties of the obtained crosslinked product were evaluated.

The results are shown in Table 1.

Blended Respi polymer ioo, o part zinc oxide 5.0 stearic acid
1.0SRF carbon
60.0 Di(2-ethylhexyl)7 tallate 5.0
Accelerator N-cyclohexy8-2-benzothiazyl sulfene 7mi F2.0 accelerator Te) Lamethylthiuram disulfy F 1.5 dicumyl peroxide 2.62-9, 1-5 According to the polymerization recipe in Table 1 Based on this, it was carried out in the same manner as in Example 1. Table 1 shows the composition and Mooney viscosity of the obtained polymer, as well as the corrosion evaluation results of the polymer and the physical property evaluation results of the crosslinked product.

However, regarding the polymer composition and styrene component of Example 8 and Comparative Example 5, the synthetic rubber SBR test method (JIS
K 6383-1977), the refractive index was calculated and the amount of bound styrene was determined.

As is clear from the results in Table 1, using terpinene, dipentene, and t-terpinene as molecular weight regulators,
Moreover, it can be seen that the polymers using a carboxylic acid emulsifier and/or a nonionic emulsifier as an emulsifier do not corrode each metal.

On the other hand, it can be seen that the conventional method of producing a polymer using t-dodecylmercaptan as a molecular weight regulator and sodium dodecylbenzenesulfonate as an emulsifier cannot prevent discoloration and corrosion of the metal surface.

〔Effect of the invention〕

The present invention provides corrosion resistance to metals by using terpenes such as terpinolene, dipentene, t-terpinene, and cyclic terpenes as a molecular tiJ1 moderator, and using a carboxylic acid emulsifier and/or a nonionic emulsifier as an emulsifier. The purpose of the present invention is to provide a polymer material that has good properties and has no adverse effects such as odor, color tone, or toxicity.

Claims (1)

[Claims] Monomers include conjugated diene monomers, α,β-unsaturated nitrile monomers, aromatic vinyl monomers, α,β-ethylenically unsaturated carboxylic acid alkyl esters, and α,β-ethylenically unsaturated Emulsion polymerization using one or more monomers selected from carboxylic acids, a carboxylic acid emulsifier and a mono- or nonionic emulsifier as an emulsifier, and a terpene compound as a molecular weight regulator. A method for producing a polymer having excellent metal corrosion resistance.