JPH03199203A - Production of polymer by emulsion polymerization - Google Patents

Abstract

PURPOSE:To obtain the subject polymer excellent in corrosion resistance of metals and free from bad influences such as odor or color tone by using a phosphate-based emulsifier as an emulsifier and using a terpene-based compound as a molecular weight modifier when carrying out emulsion polymerization in the presence of a radical initiator. CONSTITUTION:In emulsion polymerization in the presence of a radical initiator, a monomer such as 1,3-butadiene, vinylnorbornene, acrylonitrile, styrene, acrylic acid, methyl (meth)acrylate or monoethyl malate is polymerized using a phosphate-based emulsifier (e.g. polyoxyethylene alkyl phosphate monoester) as an emulsifier and a terpene-based compound (e.g. preferably terpinolene) as a molecular weight modifier, thus obtaining the objective polymer. In addition, a high-saturated polymer is obtained by hydrogenating C-C double bonds contained in the obtained polymer in the presence of a hydrogenation catalyst after production of the above-mentioned polymer.

Description

Detailed Description of the Invention The present invention provides a highly saturated polymer obtained by emulsion polymerization using a terpene compound as a molecular weight regulator and a phosphoric acid ester emulsifier as an emulsifier, or a highly saturated polymer obtained by hydrogenating the polymer. The present invention relates to a method for producing a polymer having excellent metal corrosion resistance and particularly suitable for a sealing material that comes into contact with metal.

(Prior art) Conventionally, as a method for producing a polymer 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 they are effective in controlling the molecular weight during polymerization and in processing the resulting polymer. Normal dodecyl mercaptan and tertiary dodecyl mercaptan are often used. In addition, various types of anionic emulsifiers such as carboxylic acid-based and sulfonic acid-based emulsifiers, or nonionic emulsifiers are used.

However, with a sulfur atom as a molecular weight regulator,
Rubbers polymerized using mercaptan compounds have a problem in that the sulfur compounds remaining therein corrode the metals in contact with them, particularly copper, silver, and their alloys, leading to leakage from seals. In addition, polymers obtained by emulsion polymerization in the presence of emulsifiers having sulfur atoms, such as sulfonic acid emulsifiers, also have problems for the same reason.The present inventors, in order to improve this drawback, As a result of extensive research, we have found that a polymer obtained by using a terpene compound as a molecular weight regulator and a phosphate ester emulsifier as an emulsifier does not cause discoloration or corrosion on contact or adjacent metal surfaces. We have found a fact that can be significantly improved, and have achieved the present invention based on this knowledge.

(Means for Solving the Problems) That is, the present invention uses a phosphate ester emulsifier as an emulsifier and a terpene compound as a molecular weight regulator in the production of a polymer by emulsion polymerization using a radical initiator. The present invention provides a method for producing a highly saturated polymer obtained by hydrogenating a polymer having excellent metal corrosion resistance characterized by using the above polymer.

The monomer component constituting the polymer of the present invention may be any monomer component as long as it has a copolymerizable double bond.

For example, 1,3-butadiene, isoprene, 2,3-
Conjugated diene monomers such as dimethylbutadiene and 1,3-pentadiene; Non-conjugated diene monomers such as vinylnorbornene and dicyclopentadiene; α such as acrylonitrile and methacrylonitrile;

β-Unsaturated nitrile monomers: Aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, nialic acid, methacrylic acid, itaconic acid.

α,β-unsaturated carboxylic acid monomers such as fumaric acid: methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl acrylate.

α,β-unsaturated carboxylic acid alkyl ester monomers such as: methoxyethyl (meth)acrylate.

α, β-unsaturated carboxylic acid alkoxyalkyl ester monomers such as butoxyethyl (meth)acrylate, ethoxypropyl acrylate, methoxyethoxy (meth)acrylate; cyanomethyl (meth)acrylate,
α, β-unsaturated carboxylic acid cyano W-substituted alkyl ester monomers such as 2-cyanoethyl (meth)acrylate and cyanohexyl acrylate: α such as 2-hydroxyethyl acrylate and hydroxypropyl acrylate
.

β-Unsaturated carboxylic acid hydroxyalkyl ester monomer: α such as methylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, β-unsaturated carboxylic acid aminoalkyl ester monomer: mono(di)ethyl maleate.

Unsaturated carboxylic acid ester monomers such as mono(di)ethyl fumarate, di-2ethylhexyl fumarate, di-n-butyl itaconate, monomethacrylooxyethyl succinate: trifluoroethyl(meth)acrylate, tetra Unsaturated carboxylic acid fluoroalkyl ester monomeric niacrylamide, such as fluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, pentadecafluoro(meth)octyl acrylate.

Methacrylamide, N-methylol (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N
, N'-dimethylol (meth)acrylamide, etc.
-Substituted (meth)acrylamide monomer: Other copolymerizable monomers include norbornene, glycidyl methacrylate, and allyl glycidyl ether.

Examples of copolymers made of these monomers include acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, styrene-butadiene-methacrylic acid copolymer, acrylonitrile-butadiene-butyl acrylate copolymer, and methacrylic acid copolymer. Lonitrile-butadiene-methacrylic acid copolymer, acrylonitrile-isoprene-acrylic acid-ethyl acrylate copolymer, hydrogenated conjugated diene moieties in these copolymers, butyl acrylate-methoxy acrylate-acrylic acid copolymer Examples include a butyl acrylate-ethoxyethyl acrylate-vinylnorbornene copolymer, a butyl acrylate-2hydroxyethyl acrylate-vinyl chloroacetate copolymer, and the like.

Examples of the molecular weight regulator terpene compound used in the present invention include terbinolene, α-terpinene, β-terpinene, γ-terpinene, α-pinene, β-pinene, etc. Terbinolene is preferred from the viewpoint of effectiveness. These can be used singly or in a mixture of two or more, if necessary. The amount used is 0.00% per 100 parts by weight of the monomer.
The amount is 1 to 10 parts by weight, preferably 1.0 to 7.5 parts by weight. If the amount of this molecular weight modifier is less than 0.1 part by weight, the effect as a molecular weight modifier will not be obtained, and if it exceeds 5 parts by weight, the polymerization rate will be slow and the Mooney viscosity of the polymer will be low. Productivity in molding is poor. This is not preferable because it increases costs.

Examples of phosphate emulsifiers include polyoxyethylene alkyl phosphate monoesters.

Polyoxyethylene alkyl phosphate diester.

Polyoxyethylene alkyl phosphate triester.

Examples include polyoxyethylene alkylphenyl phosphate monoester and polyoxyethylene alkylphenyl phosphate diester. The amount of these emulsifiers used is 1.0 to 10.0 parts by weight, preferably 1.5 to 7.0 parts by weight, based on 100 parts by weight of the monomer. If the amount of this emulsifier is less than 1.0 parts by weight, polymerization stability will deteriorate, and if it exceeds 10.0 parts by weight, a large amount of emulsifier will remain as impurities in the polymer, which is not preferable. Examples of the polymerization initiator 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 organic compounds. - Redox catalysts such as a combination of iron sulfate are used. Each monomer and polymerization auxiliary materials such as 2 molecules of polymerization initiator and 8 regulators 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 one reaction.

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

Polymerization is usually carried out at a reaction temperature of 0 to 70°C, preferably 5 to 50°C.
Although the reaction is carried out in a reactor from which oxygen has been removed, the temperature and operating conditions such as stirring can be changed arbitrarily during the reaction.

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, and magnesium chloride can be used. Furthermore, coagulation can also be achieved by using the above-mentioned metal compounds and the like together with a flocculant generally referred to as a polymer flocculant. In either method, it is undesirable to use compounds containing sulfur that would adversely affect metal corrosion resistance.

The polymer of the present invention can be dissolved in a solvent and used as a coating agent or adhesive, and can also be vulcanized and used as a material for sealing materials, electric circuit materials, hoses, rolls, oil-resistant packing, etc. It is particularly useful as a sealing member and an electric circuit material used in areas where metal corrosion is averse.

(Effect of the invention) The present invention uses a terpene compound as a molecular weight regulator,
In addition, by using a phosphoric acid ester emulsifier as an emulsifier, the present invention provides an excellent polymer that has better corrosion resistance to metals than conventional techniques, and has no negative effects such as odor in seven colors and toxicity. .

(Example) The present invention will be described in more detail with reference to Examples below. Note that parts and percentages in Examples and Comparative Examples are based on weight unless otherwise specified.

(Example 1) Emulsion polymerization was carried out at a temperature of 8° C. using the monomers and polymerization auxiliary materials shown below in an autoclave with an internal volume of 10 A.

Emulsion polymerization Respi Butadiene 70 parts Acrylonitrile 30 parts Water
300 parts phosphate emulsifier 1 4 parts terbinolene 2 4 parts ferrous sulfate
0.005 parts Cumene hydroperoxide 0.01 parts (*Eng.) Gafac LO-529 Manufactured by Toho Chemical Co., Ltd. (*2) Nofumer TP Manufactured by Nippon Oil & Fats Co., Ltd. When the polymerization addition rate reaches 60%, 100 parts of monomer Hit, O-
The polymerization reaction was stopped by adding 5 parts of hydroxylamine. Next, 0.5 part of anti-aging agent per 100 parts by weight was added to the latex produced, and coagulation was performed using calcium chloride. The produced crumb was washed with water and then dried with hot air vi and a dryer. A polymer was obtained.

In order to conduct a corrosion test of this polymer on a metal plate, the polymer obtained above was press-molded and 15X15X
It was cut into 10 mm cubes to form test samples. Next, a 1.5m thick copper plate was thoroughly polished and degreased.
(30mm x 30mn) with the above polymer sample
As shown in I, place the bottle in a 300 ml weighing bottle, put it in a lid, and place it in a gear oven at 80℃ for 48 hours.
After leaving it for a while, the copper plate sample was taken out and the degree of corrosion and contamination was visually checked. The results are shown in Table 1.

(Example 2) A copolymer of Example 2 was obtained in the same manner as in Example 1, except that styrene was used instead of acrylonitrile.

Corrosion tests on copper plates were conducted in the same manner as in Example 1, and the results are shown in Table 1.

(Example 3) The copolymer of Example 1 was dissolved in methyl isobutyl ketone, and the carbon-carbon double bonds in the copolymer were hydrogenated using a Pd/carbon catalyst, resulting in a hydrogenation rate of 90%. A copolymer was obtained.

A copper plate corrosion test was conducted in the same manner, and the results are shown in Table 1.

(Example 4) Polymerization was carried out in the same manner as in Example 1 using three types of monomers, acrylonitrile, butadiene, and acrylic acid, to obtain a copolymer of Example 4. A copper plate corrosion test was conducted in the same manner, and the results are shown in Table 1.

(Comparative Example 1) A copolymer of Comparative Example 1 was obtained in the same manner as in Example 1 except that the phosphoric acid ester emulsifier was changed to sodium dodecylbenzenesulfonate.

A corrosion test was similarly conducted on a copper plate, and the results are shown in Table 1.

(Comparative Example 2) Terbinolene, the molecular weight regulator of Example 1, was
A copolymer of Comparative Example 2 was obtained in the same manner except that t-dodecylmercaptan was used. A copper plate corrosion test was conducted in the same manner and the results are shown in Table 1.

As is clear from the results in Table 1, the polymer of the present invention:
It can be seen that the copper plate is not corroded.

On the other hand, it can be seen that polymers obtained using tert-dodecyl mercaptan as a molecular weight modifier or sodium dodecylbenzenesulfonate as an emulsifier cannot prevent discoloration or corrosion on the surface of a copper plate.

[Brief explanation of drawings]

FIG. 1 shows an outline of a corrosion test on a copper plate.

Claims (2)

[Claims] (1) A method for producing a polymer characterized by using a phosphate ester emulsifier as an emulsifier and a terpene compound as a molecular weight regulator in the production of a polymer by emulsion polymerization using a radical initiator. . (2) A method for producing a highly saturated polymer by producing a polymer by the method according to claim 1 and then hydrogenating the carbon-carbon double bond portion contained in the polymer using a hydrogenation catalyst.