JPS6086101A - Preparation of polymer - Google Patents

Abstract

PURPOSE:To obtain a polymer having mechanical stability of latex, improved waste water treatment properties, and processing characteristics, etc., by polymerizing a monomer containing an ethylenic double bond in an aqueous medium in the presence of a monoalkylsulfosuccinate. CONSTITUTION:A monomer (e.g., butadiene) containing an ethylenic double bond is polymerized in an aqueous medium in the presence of 0.1-10pts.wt., preferably 0.2-6.0pts.wt. monoalkylsulfosuccinate (e.g., sodium formaldehyde sulfoxylate, etc.) shown by the formula (R is 8-16C alkyl; M1 and M2 are N, K, or NH4) based on 100pts.wt. monomer.

Description

Detailed Description of the Invention The present invention is directed to the production of a latex polymer that uses monoalkyl sulfosuccinates as emulsifiers and dispersants and has excellent mechanical stability, easy drainage treatment, and improved processing characteristics. It is about the method.

Conventionally, asymmetric rosinates, fatty acid salts, alkylbenzenesulfonates, naphthalenesulfonic acid formaldehyde condensates, and the like have been used as emulsifiers and dispersants during emulsion polymerization of polymers, especially synthetic rubbers.

Emulsifiers and dispersants used in the production of synthetic rubber by emulsion polymerization are generally required to have the following properties.

That is, it does not inhibit the polymerization reaction rate, the mechanical stability of the latex during and after polymerization is excellent, it is easy to treat wastewater generated during the manufacturing process, and it has little effect on the physical properties of rubber. Among these required performances, the mechanical stability of latex is poor and the polymerization process is difficult.
Coagulation is likely to occur during the monomer recovery process, latex transfer process, etc., causing process troubles. In addition, in the treatment of wastewater, for example, formalin condensates of sodium naphthalene sulfonate have poor microbial decomposition properties and are not decomposed even by activated sludge treatment, so if they are contained in wastewater, they can be easily decomposed or recovered by normal treatment. There is a strong fear that this will cause environmental pollution due to the inability to do so.

In addition, when the rubber components are coagulated and separated from the latex, the emulsifier or dispersant may remain in the rubber, causing problems in the rubber processing process, or the properties of the final product may deteriorate. There is a strong possibility that the life of the product will be significantly reduced. Avoiding such problems is extremely important in the production of synthetic rubber.As an emulsifier for polymerization, it does not reduce the polymerization reaction rate and improves the mechanical stability of latex, making it easy to treat from the standpoint of wastewater treatment. Furthermore, there is a strong desire for an emulsifier for polymerization that does not adversely affect the polymer and physical properties.

In view of this background, the present inventors have conducted extensive research and found that -
(The present invention has been completed by discovering that the use of certain types of phosphate salts exhibits innovative properties. Namely, the present invention is based on the use of monomers having ethylenic double bonds in aqueous media. When performing radical polymerization, the general formula, H2C-C-0-R HC-C-0M2 1 M, 03SO (in the formula, R represents an alkyl group of 08 to 6, Ml and M2
The present invention provides a method for producing a polymer, characterized in that the polymerization is carried out in the presence of a monoalkylsulfoko/·phosphate salt represented by (none of which represents Na, K, or NH4, respectively).

By carrying out the present invention, in the emulsion polymerization of monomers having ethylenic double bonds, the mechanical stability of the latex during and after the polymerization is excellent, and the solid polymer is separated and washed from the polymer latex. It has excellent microbial decomposition properties for the co-phosphates discharged into the wastewater, and even if the co-phosphates remain in the polymer, there is no risk of contaminating the mold during processing, and Even when the combined substance is used in contact with metal, improved effects such as less corrosive action on metal can be obtained.The substituent R in the compound represented by the above general formula used in the present invention has 8 to 8 carbon atoms. 16 alkyl group with 8 carbon atoms
If the number of carbon atoms is less than 16, the polymerization reaction rate will drop significantly, and if the number of carbon atoms exceeds 16, it will not be possible to obtain crumbs that are large enough to be separated from the serum in the separation of the polymer by coagulation, and the crumbs will not be separated and will remain in the waste water. It leaks out. The preferred carbon number is 9 to 13. In addition, from the viewpoint of facilitating microbial decomposition, the alkyl group is preferably an unbranched straight-chain alkyl group. Both M and M2 in the general formula are Na, K
and NH, with Na or K being preferred. The amount of the succinate used in the polymerization method of the present invention is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight per 100 parts by weight of the total monomers. It is 0.2 to 6.0 parts by weight. The succinate can be used alone, or if desired, a part of the succinate can be used in place of other commonly used dispersants and emulsifiers. Examples of dispersants and emulsifiers that can be used in combination include fatty acid salts, disproportionated rosinates, alkanesulfonates, α-olefin sulfonates, alkylbenzenesulfonates,
Examples include naphthalene sulfonic acid formaldehyde condensate.

Monomers having an ethylenic double bond used in the present invention include conjugated diene monomers such as inobrene, butadiene, 1,3-pentadiene, and chloropre-7; ethyl acrylate, propyl acrylate, butyl acrylate,
Alkyl esters of acrylic acid or methacrylic acid such as methyl methacrylate; metquin methyl acrylate;
Alkoxyalkyl acrylates such as ethoxyethyl acrylate and butoxyethyl acrylate; unsaturated monomers containing epoxy groups such as vinyl glycidyl ether, allyl glycidyl ether, and glycidyl methacrylate-1; acrylic acid, methacrylic acid, maleic acid, itaconic acid Aromatic vinyl monomers such as styrene and α-methylstyrene; unsaturated carboxylic acids such as acrylonitrile and methacrylonitrile; vinyl monomers such as vinyl acetate and vinyl chloride; Examples include the body, etc.
The monomer is not limited to these as long as it is a monomer that can be radically polymerized. The exemplified monomers can be used alone or in combination of two or more. The method of the invention is particularly suitable for the production of rubbery polymers such as polybutanecom, polyisoprene rubber, butadiene-styrene copolymer rubber, acrylonitrile-butadiene copolymer rubber, so-called acrylic rubber.

As the radical polymerization initiator used in the present invention, commonly used radical polymerization initiators can be used, and there are no particular limitations. Typical initiators include, for example, persulfates such as potassium persulfate and ammonium persulfate, and letosox initiators. Molecular weight regulators, chelating agents, chemical agents, etc. may be those used in normal emulsion polymerization (there are no particular restrictions.The polymerization method may be batch, semi-batch, continuous, etc.). The polymerization temperature may be either low or high temperature.In short, in the polymerization method of the present invention, known radical emulsion polymerization methods can be used, except that monoalkyl sulfosuccinate is used as an emulsifier and a dispersant.

The present invention will be specifically explained below using Examples.

Table 1 shows emulsifiers and dispersants used in the following examples.

Table 1 Example 1 Acrylonitrile/butadiene copolymer (hereinafter NBR
) was prepared by polymerization at 5°C in a pressure vessel according to the following polymerization recipe. The pH of the system was adjusted to 10.5 in advance.

(Polymerization recipe) (parts by weight) Emulsifiers, dispersants (see Table 2) 3.

Sodium carbonate 0.1 Deionized water 190 Acrylonitrile 34 Butadiene 66 Ethylenediaminetetraacetic acid tetrasulium salt 0.03
Tertiary dotesyl mercaptan 0.43FeSO,・7
H200,005 Sodium formaldehyde sulfoxylate. ,o
5p-menthane hydroperoxide 0.06 When the polymerization conversion rate reached 84, 0.5 part of sodium dimethyldithiocarbamate was added to stop the polymerization.

The stability of the obtained latex was measured by the following method and the results are shown in Table 2.

[Latex stability-1] After stopping the polymerization, remove unreacted monomers by steam distillation, collect the coagulated material with 80 mesh gold steel, weigh the amount of agglomerates after washing and drying with water, and calculate the ratio to the weight of the produced polymer. show. The lower the value, the better the mechanical stability of the latex.

[Latex Stability-2] The latex from which unreacted monomers had been removed was placed in a mixer manufactured by Hamilton Beach Co., Ltd. (Kai-51 Drink Master), and the latex was forcibly stirred at a temperature of 50°C and a rotational speed of Jl, 000 rpm for 5 minutes, and the resulting aggregates were dried. The ratio of the weight to the total solid weight of the sample latex was defined as latex stability 2. The lower the number, the better the stability.

From the results in Table 2, it can be seen that the emulsifier of the present invention has better latex stability than conventionally used emulsifiers and dispersants. Experiment No. 11 (comparative example) shows latex stability equivalent to that of the present invention, but as described later, when used as a solid rubber, mold contamination and metal debris tactility are extremely poor.

Experiment number 4 in Table 2. Add 1 part by weight of a6-di-t-butyl-p-cresol as a stabilizer to the latex of 6.10 and 1, remove unreacted monomers by steam distillation, and then add calcium chloride to make NBR. After coagulating, washing and drying, an NBR mixture was prepared using a 6-inch roll according to the formulation shown in Table 3, and JISK-630
Physical properties were measured according to 0.6301 (vulcanization conditions 160
℃, 20 min press vulcanization). The metal contamination property was evaluated using a 5-point method by observing the degree of contamination of the mold after placing the NBR mixture in the mold and press vulcanizing it (1 point for no staining to 5 points for very much staining). Metal scrap tactility was determined by testing two sheets of NBR vulcanizate according to GM Test Method 9003-P [SAE] 020
Place it between two metal plates and place it in a desiccator filled with water.
It was left at 40°C for 96 hours. The degree of corrosion of the metal plate after the test was evaluated according to the test method using a scoring system ranging from 0 points (no corrosion) to 5 points (severely corrosive).

The above results are shown in Table 4.

Table 3 (Composition) NBR 100 parts by weight Zinc white %] 5 Stearic acid 1 SRF carbon black 5o Dioctyl phthalate 5 Sulfur 0.5 Tetramethylthiuram disulfide 1.5 Cyclohexylbenzothiazyl sulfenamide 1 .5th
4 It is clear from the results in Table 4 that the examples of the present invention have no adverse effect on the physical properties of rubber such as Mooney scorch and tensile tests.
Mold contamination and metal corrosion are significantly improved.

Example 2 A copolymer of ethyl acrylate/glycidyl methacrylate was prepared according to the following polymerization recipe using 24 separate flasks. Prior to polymerization, first, charge each substance in a flask, adjust the I)H of the mixture in the flask to 7, raise the temperature in the system to 5°C while stirring, and repeat deaeration and nitrogen replacement in the system. After sufficiently removing oxygen, each substance (2) was added and polymerization was carried out at 5°C.

(Polymerization recipe) (Parts by weight) Polymerization was completed in about 16 hours, and the polymerization conversion rate at that time was 95~
It was in the range of 99 inches. The stability of the obtained latex was measured in the same manner as in Example 1, and the results are shown in page 5.

Table 5 (Note) Emulsifier and dispersant shown in Table 1 Example 3 A styrene/butadiene copolymer was prepared by polymerization at 5°C in a pressure vessel according to the following polymerization recipe.

(Polymerization recipe) (Parts by weight) Deionized water 200 Emulsifiers and dispersants shown in Table 1 4.1 Styrene 28 Phrydien 72 Sodium triphosphate, -2H200,8 Sodium formaltehyde sulfoxylate 0.15FcsO4 7
H200,005 Ethylenediaminetetraacetic acid tetrasodium salt 0.07
Tertiary dodecyl mercaptan 0.2 p-nontane hydroperoxide 0.1 When the polymerization conversion reached 65±3, 0.5 part of sodium dimethyldithiocarbamate was added to stop the polymerization. The stability of the obtained latex was measured and the results are not shown in Table 6.

Table 6 From the results shown in Tables 5 and 6, it can be seen that the emulsifiers of the examples of the present invention exhibit far superior latex stability than conventional emulsifiers and dispersants.

Patent applicant: Nippon Zeo/Co., Ltd.

Claims (1)

[Claims] When radically polymerizing a monomer having an ethylenic double bond in an aqueous medium, the general formula % formula % (wherein R represents a C8-6 alkyl group, M, and M2
A method for producing a polymer, characterized in that the polymerization is carried out in the presence of a monoalkyl sulfosuccinate represented by Na, Na, and NL, respectively.