JP2014129470A - Polychloroprene and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polychloroprene including an emulsifier other than rosinates and a method for manufacturing the same.SOLUTION: A water-soluble petroleum resin is obtained by reacting, with a basic compound, an α,β-unsaturated dicarboxylic anhydride-modified petroleum resin obtained by reacting an α,β-unsaturated dicarboxylic anhydride and a petroleum resin. It has been discovered, in particular, that, if a water-soluble petroleum resin having a critical micelle concentration of 180 g/L or below is used for the emulsion polymerization of chloroprene, a high-quality polychloroprene is obtained in a high productivity.

Description

  The present invention relates to polychloroprene and a method for producing the same, and more particularly to polychloroprene containing a water-soluble petroleum resin and a method for producing the same.

  As a method for producing polychloroprene, a method of carrying out emulsion polymerization of a chloroprene monomer in an aqueous emulsion containing an emulsifier and an initiator in the presence of a chain transfer agent is widely known.

  Conventional emulsifiers used for polymerization include anionic emulsifiers such as rosinates, higher fatty acid salts, alkylbenzene sulfonates, nonionic emulsifiers such as polyoxyethylene alkyl ethers and polyvinyl alcohols, alkylamine salts, quaternary ammoniums. Cationic emulsifiers such as salts and amphoteric emulsifiers such as alkylbetaines and alkylamine oxides are known, and any one or more of these emulsifiers are used alone or in combination. In particular, in emulsion polymerization of chloroprene, anionic emulsifiers, particularly rosinates are preferably used (Patent Documents 1 to 5).

  However, since rosin is a natural product obtained from pine family plants such as Maomatsu, its production is not only difficult and laborious, but also a long time from pine planting to rosin recovery. Since it took a month, there was a problem in stable supply.

  Then, the new emulsifier which changes to the conventional method is examined (patent document 6).

  However, such a method is still a complicated method, and high-quality polychloroprene using a high-performance emulsifier obtained by a simpler method has been demanded.

JP 2006-307156 A JP 2011-122141 A JP 2007-332207 A JP 2009-191182 A JP 2010-006902 A JP20112344631A

  This invention is made | formed in view of said subject, The objective provides the polychloroprene containing new emulsifiers other than rosinates, and its manufacturing method.

  As a result of intensive studies to solve the above problems, the present inventors have found that polychloroprene using a petroleum resin, particularly a water-soluble petroleum resin having a critical micelle concentration of 180 g / L or less, as a new emulsifier other than rosinates. It has been found that the productivity is high and the quality is high, and the present invention has been completed. That is, this invention is a polychloroprene characterized by including the water-soluble petroleum resin of the critical micelle density | concentration of 180 g / L or less, and its manufacturing method.

  The present invention is described in further detail below.

  The polychloroprene of the present invention contains a water-soluble petroleum resin having a critical micelle concentration of 180 g / L or less.

  Petroleum resin is a resin that is obtained by polymerizing a part of naphtha decomposition by-product oil (highly unsaturated diene) used in the petrochemical industry as a raw material. Examples of petroleum resins to be used include aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, and the like, and at least one selected from these can be used. preferable.

  The water-soluble petroleum resin can be obtained, for example, by the following steps (1) and (2).

(1) Step: Step of reacting α, β-unsaturated dicarboxylic acid anhydride with petroleum resin to obtain α, β-unsaturated dicarboxylic acid anhydride-modified petroleum resin (2) Step: Obtained by step (1) A step of reacting the obtained α, β-unsaturated dicarboxylic acid anhydride-modified petroleum resin with a basic compound to form a water-soluble petroleum resin. Here, α, β-unsaturated dicarboxylic acid anhydride is α, β -Any compound can be used as long as it belongs to the category of unsaturated dicarboxylic acid anhydrides. Among them, α, β-unsaturated dicarboxylic acid anhydrides having 3 to 36 carbon atoms are preferable, 18 α, β-unsaturated dicarboxylic anhydrides are particularly preferred. For example, maleic anhydride, citraconic anhydride, chloromaleic anhydride and the like can be mentioned. Among them, maleic anhydride is preferred because of excellent reaction efficiency and easy availability.

  The step (2) is a step of reacting the α, β-unsaturated dicarboxylic anhydride modified petroleum resin obtained in the step (1) with a basic compound to obtain a water-soluble petroleum resin.

  As the basic compound, any compound that belongs to the category of basic compounds can be used. For example, lithium hydroxide, potassium hydroxide, sodium hydroxide, rubidium hydroxide, cesium hydroxide and the like can be used. Examples include alkali metal hydroxides; alkylamines such as trimethylamine, triethylamine, tripropylamine, and dimethylethylamine; and amine compounds such as alkanolamines such as trimethanolamine, triethanolamine, diethanolamine, and monoethanolamine. Among them, sodium hydroxide, potassium hydroxide, trimethanolamine, and triethanolamine are particularly preferable because petroleum resins having excellent water solubility can be easily and efficiently produced.

  The water-soluble petroleum resin contained in the polychloroprene of the present invention has a critical micelle concentration of 180 g / L or less. The critical micelle concentration is the concentration of the surfactant when the surfactant starts to form micelles in the solution, and no micelle is formed below this concentration. If the critical micelle concentration exceeds 180 g / L, the emulsifying power at the time of polymerization of rubber is insufficient, and stable emulsion polymerization becomes difficult, and the quality of the resulting polymer is lowered. For example, the latex generated during emulsion polymerization becomes unstable, and problems such as rubber precipitation in the liquid occur.

  In the polychloroprene of the present invention, the content of the above-mentioned water-soluble petroleum resin is not particularly limited, but since the latex becomes more stable and the polymerization rate can be increased, the polychloroprene polymer with respect to 100 parts by weight of the polychloroprene polymer, The amount is preferably 5 to 30 parts by weight, and more preferably 5 to 20 parts by weight.

  The polychloroprene of the present invention can be produced by adding 5 to 30 parts by weight of the water-soluble petroleum resin to 100 parts by weight of the chloroprene monomer and performing emulsion polymerization. It is preferable that it is a weight part.

  In emulsion polymerization, a chloroprene monomer alone or a mixture of a chloroprene monomer and a monomer copolymerizable therewith can be used as a raw material.

  Examples of the copolymerizable monomer include 2,3-dichloro-1,3-butadiene, 2-cyano-1,3-butadiene, 1-chloro-1,3-butadiene, 1,3-butadiene, Styrene, acrylonitrile, methyl methacrylate, methacrylic acid, acrylic acid and the like can be mentioned. Among these, these are used alone or in combination of two or more. The amount containing these monomers is not particularly limited, but is preferably 0 to 30% by weight as long as the properties of the polychloroprene obtained are not impaired.

  In the polymerization reaction, for example, a chain transfer agent is added to a mixture of a chloroprene monomer alone or a chloroprene monomer and a copolymerizable monomer, and an aqueous emulsion containing an emulsifier and a pH adjuster is mixed. Suspend.

  The conditions for the polymerization reaction are not particularly limited. For example, the catalyst solution can be added at a temperature of 0 to 60 ° C. and a pH of 7 to 13 of the polymerization system while mixing and stirring.

  The chain transfer agent is used to adjust the molecular weight of the obtained polymer as intended, to prevent the obtained polymer from forming a crosslinked polymer structure, and to allow polychloroprene to be processed and molded as a rubber. About 0.01 to 1.0 part by weight with respect to 100 parts by weight of the monomer mixture other than the chain transfer agent. The type of chain transfer agent is not particularly limited, and examples thereof include molecular weight regulators such as alkyl mercaptans, halogen hydrocarbons, alkyl xanthogen disulfides, sulfur, etc. Of these, n from the viewpoint of odor and workability. -Dodecyl mercaptan is preferred.

  As a pH regulator, any one or more of basic compounds such as sodium hydroxide, potassium hydroxide, sodium phosphate, potassium phosphate, triethylamine, diethylamine, triethanolamine, diethanolamine, ethanolamine, and ammonia are used alone or in combination. And use.

  As a catalyst for initiating polymerization, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, t-butyl hydroperoxide, or the like can be used.

  The polymerization is carried out to a polymerization conversion rate of about 60 to 99%, and then stopped by adding a small amount of a polymerization inhibitor. The polymerization inhibitor to be used is not particularly limited. For example, thiodiphenylamine, 4-t-butylcatechol, 2,6-di-t-butyl-4-methylphenol, 2,2′-methylenebis (4-ethyl-6) -T-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), hydroquinone, N, N-diethylhydroxyl An amine etc. are mentioned, Among these, 1 or more types can be used individually or in combination.

  From the obtained polymer latex, unreacted monomers are removed and recovered by a vacuum stripping method, and the desired polychloroprene is obtained in a latex state. The latex may be used as it is as a latex or may be used as polychloroprene rubber by a method such as drying or freeze drying.

  The present invention will be specifically described by the following examples, but the present invention is not limited thereto.

<Measurement method of critical micelle concentration>
The surface tension was measured using a surface tension meter (ESB-V, manufactured by Kyowa Science Co., Ltd.), and the obtained surface tension was plotted against the concentration (logarithmic concentration) of the water-soluble petroleum resin. The lowest concentration at which is constant was determined as the critical micelle concentration.

<Evaluation method of state after low temperature storage>
The obtained latex was allowed to stand in a low-temperature atmosphere (5 ° C.) for 7 days, and the low-temperature storage property was evaluated by confirming the precipitation of the rubber component in the latex.

Example 1
After 1000 g of petroleum resin (Petrotac (registered trademark) 70, manufactured by Tosoh Corporation, aliphatic / aromatic copolymer petroleum resin) was heated and melted at 250 ° C., 250 g of maleic anhydride was added, and 250 ° C. The reaction was carried out for 2 hours to obtain a maleic anhydride-modified petroleum resin. To 1000 g of the resulting maleic anhydride-modified petroleum resin, 4000 g of a 5% aqueous potassium hydroxide solution was added, and the reaction was carried out by stirring for 10 hours under reflux at 85 ° C. to obtain a water-soluble petroleum resin (critical micelle concentration 50-100 g / L). Got.

  As a monomer mixture, 0.5 g of n-dodecyl mercaptan is added to 1000 g of chloroprene monomer, 100 g of water-soluble petroleum resin (10 parts by weight with respect to 100 parts by weight of chloroprene monomer), naphthalenesulfonic acid and formaldehyde The mixture was stirred and mixed with an emulsified aqueous solution containing 5 g of a sodium salt of the condensate, 0.5 g of sodium hydroxide and 1000 g of water. A polymerization catalyst consisting of 1 g of potassium persulfate, 0.1 g of sodium anthraquinone-β-sulfonate, and 300 g of water was added at a constant rate by a pump to carry out polymerization. The polymerization is carried out by adding a polymerization catalyst until the polymerization conversion rate reaches 90%. Here, 0.5 g of 4-t-butylcatechol, 0.5 g of phenothiazine, 5 g of sodium dodecylbenzenesulfonate, 30 g of chloroprene and 30 g of water are stopped. The polymerization was stopped by adding an agent. Thereafter, unreacted chloroprene was removed and recovered by steam stripping under reduced pressure to obtain a polychloroprene latex. About the obtained polychloroprene latex, the state after low-temperature storage was evaluated. The results are shown in Table 1. The obtained polychloroprene latex was excellent in storage stability at a low temperature (5 ° C.) without precipitation of rubber.

Example 2
A polychloroprene latex was obtained in the same manner as in Example 1 except that the water-soluble petroleum resin was changed to 200 g (20 parts by weight with respect to 100 parts by weight of the chloroprene monomer) with respect to 1000 g of the chloroprene monomer. The later state was evaluated. The obtained polychloroprene latex was excellent in storage stability at a low temperature (5 ° C.) without precipitation of rubber.

Example 3
A polychloroprene latex was obtained in the same manner as in Example 1 except that the water-soluble petroleum resin was changed to 300 g (30 parts by weight relative to 100 parts by weight of the chloroprene monomer) with respect to 1000 g of the chloroprene monomer, and stored at low temperature. The later state was evaluated. The obtained polychloroprene latex was excellent in storage stability at a low temperature (5 ° C.) without precipitation of rubber.

Comparative Example 1
Polymerization was carried out in the same manner as in Example 1, except that the water-soluble petroleum resin (critical micelle concentration 200 to 300 g / L) obtained using petroleum resin (Petrotac (registered trademark) 1140, manufactured by Tosoh Corporation) was used. However, polymerization did not proceed and polychloroprene could not be obtained.

Comparative Example 2
Example 1 except that the water-soluble petroleum resin added to 1000 g of the chloroprene monomer was changed to a petroleum resin (Petrotac (registered trademark) 70, manufactured by Tosoh Corporation, aliphatic / aromatic copolymer petroleum resin). Polymerization was carried out in the same manner as in Example 1, but emulsification did not occur and polychloroprene could not be obtained.

  The polychloroprene of the present invention can achieve the same high quality as rosin that has been widely used in emulsion polymerization.

Claims (4)

A polychloroprene comprising a water-soluble petroleum resin having a critical micelle concentration of 180 g / L or less. The polychloroprene according to claim 1, comprising 5 to 30 parts by weight of a water-soluble petroleum resin having a critical micelle concentration of 180 g / L or less based on 100 parts by weight of the polychloroprene polymer. The petroleum resin is at least one selected from an aliphatic petroleum resin, an aromatic petroleum resin, and an aliphatic-aromatic copolymer petroleum resin. Polychloroprene. The emulsion polymerization is carried out by adding 5 to 30 parts by weight of a water-soluble petroleum resin having a critical micelle concentration of 180 g / L or less to 100 parts by weight of the chloroprene monomer. The manufacturing method of the polychloroprene as described in the term.