JP2005290047A - Method for producing synthetic rubber latex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a synthetic rubber latex. <P>SOLUTION: The method for the production of a synthetic rubber latex comprises the emulsion polymerization of a conjugated diene monomer, an ethylenically unsaturated monomer and a dicarboxylic acid monomer having an ethylenically unsaturated group by using an emulsifier composed of (d1) a straight-chain alkylbenzenesulfonic acid sodium salt having a benzene ring added to the 2-position of the alkyl group, (d2) a straight-chain alkylbenzenesulfonic acid sodium salt having a benzene ring added to the 3-position of the alkyl group, (d3) a straight-chain alkylbenzenesulfonic acid sodium salt having a benzene ring added to the 4-position of the alkyl group, (d4) a straight-chain alkylbenzenesulfonic acid sodium salt having a benzene ring added to the 5-position of the alkyl group and (d5) a straight-chain alkylbenzenesulfonic acid sodium salt having a benzene ring added to the 6-position of the alkyl group, provided that the weight ratio [ä(d1)+(d2)}/ä(d1)+(d2)+(d3)+(d4)+(d5)}] is 0.38-1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a production method capable of efficiently producing a synthetic rubber latex.

  Latex is generally a spherical polymer substance (polymer) dispersed in water, and is used in a wide range of fields such as construction / civil engineering, paint, paper processing, and textile processing. As a production method for synthesizing this latex, for example, emulsion polymerization is used. Synthetic rubber latex using this emulsion polymerization is, for example, a conjugated diene monomer, an ethylenically unsaturated monomer and a dicarboxylic acid monomer having an ethylenically unsaturated group in water using an alkylbenzenesulfonic acid-based emulsifier. It is manufactured by a method of performing emulsion polymerization (see, for example, Patent Document 1).

  However, in the production method of Patent Document 1, a dicarboxylic acid monomer having an ethylenically unsaturated group, such as fumaric acid, has poor solubility in water as an emulsion polymerization medium, and as a result, polymerization proceeds. First, it is very difficult to efficiently produce a good synthetic rubber latex.

JP 2001-139694 A

  The subject of this invention is providing the manufacturing method which can obtain synthetic rubber latex efficiently.

As a result of intensive studies, the present inventors have found the following findings and have completed the present invention.
(1) As an emulsifier used in the emulsion polymerization, a linear alkyl sodium benzenesulfonate (d1) having a benzene ring bonded to the 2-position of the linear alkyl group or a benzene ring bonded to the 3-position of the linear alkyl group When an alkylbenzene sulfonic acid-based emulsifier containing linear sodium alkylbenzene sulfonate (d2) is used, the solubility of ethylenically unsaturated monomers containing two carboxyl groups in water is improved and efficient synthesis is achieved. Rubber latex can be produced.
(2) Sodium linear alkylbenzenesulfonate (d3) having a benzene ring bonded to the 4-position of the linear alkyl group usually mixed as a by-product when producing the above (d1) and (d2), linear alkyl group Alkylbenzene sulfone containing a linear alkylbenzene sulfonate sodium (d4) having a benzene ring bonded to the 5-position and a linear alkylbenzene sulfonate sodium (d5) having a benzene ring bonded to the 6-position of the linear alkyl group The acid-based emulsifier has no emulsifying property to ensure the solubility (water solubility) of the ethylenically unsaturated monomer containing two carboxyl groups in water, and efficiently produces a good synthetic rubber latex. I can't.
(3) Even if (d3), (d4) and (d5) are mixed in (d1) and (d2), the weight ratio [{(d1) + (d2)} / {(d1) + If (d2) + (d3) + (d4) + (d5)}] has a relationship of 0, 38 to 1, a good synthetic rubber latex can be produced efficiently.

  That is, the present invention relates to an ethylenically unsaturated monomer other than the conjugated diene monomer (A), the ethylenically unsaturated monomer (B) containing two carboxyl groups, and the ethylenically unsaturated monomer (B). Monomer (C) is a linear alkylbenzenesulfonate sodium (d1) in which a benzene ring is added to the 2-position of the linear alkyl group, and a linear chain in which the benzene ring is bonded to the 3-position of the linear alkyl group. Sodium alkylbenzenesulfonate (d2), linear alkylbenzenesulfonate sodium (d3) with a benzene ring bonded to the 4-position of the linear alkyl group, linear chain with a benzene ring bonded to the 5-position of the linear alkyl group Sodium alkylbenzene sulfonate (d4) and linear alkyl benzene sulfonate sodium (d5) having a benzene ring bonded to the 6-position of the linear alkyl group Alkylbenzenesulfone contained so that [{(d1) + (d2)} / {(d1) + (d2) + (d3) + (d4) + (d5)}] is 0.38 to 1 by weight ratio An object of the present invention is to provide a method for producing a synthetic rubber latex characterized by emulsion polymerization in the presence of a sodium acid emulsifier.

  According to the present invention, synthetic rubber latex can be produced efficiently, and the obtained synthetic rubber latex can be preferably used in various industries, particularly in the paper processing field.

  As the conjugated diene monomer (A) used in the present invention, for example, butadiene, isoprene and the like can be preferably used. A conjugated diene monomer (A) may be used independently and may use 2 or more types together.

  Examples of the ethylenically unsaturated monomer (B) containing two carboxyl groups used in the present invention include fumaric acid, maleic acid, itaconic acid and the like. The dicarboxylic acid monomer (C) having an ethylenically unsaturated group may be used alone or in combination of two or more.

  Among ethylenically unsaturated monomers (B) containing two carboxyl groups, fumaric acid, maleic acid and the like, for example, have relatively poor solubility in water. In that case, the solubility in water can be improved by partially neutralizing these acids with a base before the start of polymerization. The base to be used is not particularly limited, but ammonia and potassium hydroxide are preferable.

  Examples of the ethylenically unsaturated monomer (C) other than the ethylenically unsaturated monomer (B) used in the present invention include styrene, α-methylstyrene, vinyl toluene, chlorostyrene, acrylonitrile, methacrylonitrile and the like. Can be mentioned. An ethylenically unsaturated monomer (B) may be used independently and may use 2 or more types together.

  Ethylenically unsaturated monomers (C) other than the conjugated diene monomer (A), the ethylenically unsaturated monomer (B) containing two carboxyl groups, and the ethylenically unsaturated monomer (B) ) Is preferably used in a weight ratio of 35 to 55/3 to 1/40 to 60 ([A] / (B) / (C)].

  The emulsifier (D) used in the present invention is a straight chain sodium alkylbenzenesulfonate (d1) having a benzene ring bonded to the 2-position of the linear alkyl group, and a straight chain having a benzene ring bonded to the 3-position of the linear alkyl group. Sodium alkylbenzene sulfonate (d2), linear alkylbenzene sulfonate sodium (d3) with a benzene ring bonded to the 4-position of the linear alkyl group, straight chain benzene ring bonded to the 5-position of the linear alkyl group Sodium alkylbenzenesulfonate (d4) and linear alkylbenzenesulfonate sodium (d5) having a benzene ring bonded to the 6-position of the linear alkyl group in a weight ratio [{(d1) + (d2)} / Alkylbenzenes contained so that {(d1) + (d2) + (d3) + (d4) + (d5)}] is 0.38 to 1 There is a need to be acid-based emulsifier. When [{(d1) + (d2)} / {(d1) + (d2) + (d3) + (d4) + (d5)}] is smaller than 0.38, ethylenic group containing two carboxyl groups It is not preferable because the solubility of the unsaturated monomer (B) cannot be sufficiently improved and a synthetic rubber latex cannot be produced efficiently. The above-mentioned [{(d1) + (d2)} / {(d1) + (d2) + (d3) + (d4) + (d5)}] of the emulsifier (D) used in the present invention is 0.45 to 1. A certain emulsifier is more preferable, and the emulsifier which is 0.47-0.8 is still more preferable.

  The abundance (existence weight) of (d1), (d2), (d3), (d4) and (d5) in the alkylbenzenesulfonic acid emulsifier can be determined by, for example, a liquid chromatography method.

  Examples of the alkyl group possessed by (d1), (d2), (d3), (d4) and (d5) include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, Examples include octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and eicosyl group. As the alkyl group, an alkyl group having 9 to 15 carbon atoms is preferable, and an alkyl group having 11 to 13 carbon atoms is more preferable.

  The production method of the emulsifier (D) used in the present invention is not particularly limited, but can be preferably produced by, for example, a method in which paraffin and benzene are reacted in the presence of aluminum chloride. Examples of commercially available products include “Neogen S-20” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Neopelex F-25” manufactured by Kao Corporation, “POLYSTEP A-15” manufactured by Stepan Company of the United States, and the like. Can be mentioned.

  The production method of the present invention includes, for example, a conjugated diene monomer (A), an ethylenically unsaturated monomer (B) containing two carboxyl groups, and an ethylenically unsaturated monomer in a pressure-resistant reactor for polymerization. (E) Other than (B), an ethylenically unsaturated monomer (C), an emulsifier used in the present invention, water, a catalyst, etc. are charged, the reaction system is purged with nitrogen, oxygen is removed, and the reaction is conducted under heating. Can be mentioned.

  In charging various raw materials into the polymerization pressure reactor, an ethylenically unsaturated monomer (B) containing two water and carboxyl groups, an emulsifier and a basic compound used in the present invention are mixed in advance. The partial neutralization of the ethylenically unsaturated monomer (B) containing two carboxyl groups with a basic compound and the dissolution of the ethylenically unsaturated monomer (B) containing two carboxyl groups in water; May be performed.

  As the catalyst, any catalyst can be used without particular limitation as long as it can be used in the production of synthetic rubber latex. For example, ammonium persulfate is preferable. Moreover, the use of a metal sealant is effective in order to facilitate the polymerization, and ethylenediaminetetraacetic acid and its neutralized salts can be preferably used. The metal sealant may be added to the reaction system simultaneously with the catalyst. For example, partial neutralization of the ethylenically unsaturated monomer (B) containing two carboxyl groups described above with a basic compound and the addition to water. It may be added when dissolving the ethylenically unsaturated monomer (B) containing two carboxyl groups in advance.

  In the production method of the present invention, the emulsion polymerization is preferably carried out under conditions of pH 1 to 5, and more preferably carried out under conditions of pH 3.5 to 5.

  The amount of the emulsifier used in the present invention is ethylenic other than the conjugated diene monomer (A), the ethylenically unsaturated monomer (B) containing two carboxyl groups, and the ethylenically unsaturated monomer (B). Usually, 0.5 to 1.5 parts by weight is preferable with respect to 100 parts by weight of the unsaturated monomers (C) in total.

  65-85 degreeC is preferable and the reaction temperature at the time of performing emulsion polymerization has more preferable 70-80 degreeC. The reaction time is preferably 10 to 15 hours, more preferably 12 to 14 hours.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

Example 1
454.8 grams of water, 14.8 grams of fumaric acid, 10.2 grams of 25% aqueous ammonia, 23.2 grams of Neoperex F-25, 0.25 grams of ethylenediaminetetraacetic acid disodium salt Was added and mixed. The pH at this time was 4. Furthermore, 250.4 grams of styrene and 4.2 grams of tert-dodecyl mercaptan were charged, and the inside of the kettle was purged with nitrogen to eliminate oxygen. After injecting 244.8 grams of butadiene, the temperature was raised by heating, and when the temperature reached 70 ° C., an aqueous solution in which 7.65 grams of ammonium persulfate was dissolved in 68.9 grams of water was injected. After maintaining at 70 ° C. for 8 hours, the temperature was raised to 78 ° C., and the reaction was further continued at 78 ° C. for 5 hours. Thereafter, the mixture was cooled to obtain a synthetic rubber latex having a solid content of about 47% and a viscosity of 180 mPa · sec. When the obtained synthetic rubber latex was confirmed with the naked eye, the polymerization reaction was completed, and a synthetic rubber latex having a quality that could withstand use could be efficiently produced. Neoperex F-25 used here is a linear alkylbenzene sulfonate-based emulsifier manufactured by Kao Corporation, and the above-mentioned [{(d1) + (d2)} / {(d1) + (d2) + The value of (d3) + (d4) + (d5)}] is 0.51. Neoperex F-25 is 5.2% by weight of linear alkylbenzene sulfonate sodium having an alkyl group having 10 carbon atoms, and 30.9% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 11 carbon atoms. Containing 32.1% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 12 carbon atoms and 21.9% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 13 carbon atoms.

Comparative Example 1
In a pressure-resistant reactor for polymerization, 454.8 grams of water, 14.8 grams of fumaric acid, 10.2 grams of 25% aqueous ammonia, 23.2 grams of Neogen S-20F, and 0.25 grams of ethylenediaminetetraacetic acid disodium salt Charged and mixed. The pH at this time was 4. Furthermore, 250.4 grams of styrene and 4.2 grams of tert-dodecyl mercaptan were charged, and the inside of the kettle was purged with nitrogen to eliminate oxygen. After injecting 244.8 grams of butadiene, the temperature was raised by heating, and when the temperature reached 70 ° C., an aqueous solution in which 7.65 grams of ammonium persulfate was dissolved in 68.9 grams of water was injected. Although the temperature was kept at 70 ° C., stirring was stopped when 6 hours passed. When the temperature in the reaction system was lowered to room temperature and the reaction apparatus was opened and the inside of the apparatus was checked, it was observed that a polymer with extremely high viscosity adhered to the stirrer and the stirring blade, and the polymerization reaction was not completed. It was judged. In addition, neogen S-20F used here is a linear alkylbenzene sulfonate sodium emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd., [{(d1) + (d2)} / {(d1) + (d2 ) + (D3) + (d4) + (d5)}] is 0.36. In addition, Neogen S-20F is 9.4% by weight of linear alkylbenzene sulfonate sodium having an alkyl group having 10 carbon atoms, and 32.4% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 11 carbon atoms. And containing 39.2% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 12 carbon atoms and 19.2% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 13 carbon atoms.

Comparative Example 2
454.8 grams of water, 14.8 grams of fumaric acid, 10.2 grams of 25% aqueous ammonia, 23.2 grams of Neoperex G-15, 0.25 grams of ethylenediaminetetraacetic acid disodium salt Was added and mixed. The pH at this time was 4. Furthermore, 250.4 grams of styrene and 4.2 grams of tert-dodecyl mercaptan were charged, and the inside of the kettle was purged with nitrogen to eliminate oxygen. After injecting 244.8 grams of butadiene, the temperature was raised by heating, and when the temperature reached 70 ° C., an aqueous solution in which 7.65 grams of ammonium persulfate was dissolved in 68.9 grams of water was injected. After maintaining at 70 ° C. for 8 hours, the temperature was raised to 78 ° C., and the reaction was further continued at 78 ° C. for 5 hours. After cooling, the product was confirmed, but a large amount of unreacted monomer remained, the polymerization rate was about 50%, and the polymerization reaction was not completed. Neoperex G-15 used here is a linear alkylbenzene sulfonate sodium emulsifier manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., and the above-mentioned [{(d1) + (d2)} / {(d1) + (d2) + (D3) + (d4) + (d5)}] is 0.36. Neoperex G-15 is 9.4% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 10 carbon atoms, and 32.4% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 11 carbon atoms. 39.2% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 12 carbon atoms and 19.2% by weight of sodium linear alkylbenzene sulfonate having an alkyl group having 13 carbon atoms.

Claims (4)

Conjugated diene monomer (A), ethylenically unsaturated monomer (B) containing two carboxyl groups, and ethylenically unsaturated monomer (C) other than said ethylenically unsaturated monomer (B) Sodium alkylbenzene sulfonate (d1) having a benzene ring added to the 2-position of the linear alkyl group, and sodium linear alkylbenzene sulfonate (d2) having a benzene ring bonded to the 3-position of the linear alkyl group. ), Sodium linear alkylbenzenesulfonate (d3) having a benzene ring bonded to the 4-position of the linear alkyl group, and linear sodium alkylbenzenesulfonate (d4) having a benzene ring bonded to the 5-position of the linear alkyl group ) And sodium linear alkylbenzenesulfonate (d5) having a benzene ring bonded to the 6-position of the linear alkyl group in a weight ratio [{( 1) + (d2)} / {(d1) + (d2) + (d3) + (d4) + (d5)}] Presence of sodium alkylbenzene sulfonate emulsifier containing 0.38-1 A process for producing a synthetic rubber latex, characterized in that emulsion polymerization is carried out. The composition according to claim 1, wherein [{(d1) + (d2)} / {(d1) + (d2) + (d3) + (d4) + (d5)}] is 0.47 to 0.8. A method for producing rubber latex. The synthetic rubber latex according to claim 1, wherein the linear alkyl group in the (d1), (d2), (d3), (d4) and (d5) is a linear alkyl group having 9 to 15 carbon atoms. Method. The manufacturing method of the synthetic rubber latex of any one of Claims 1-3 which perform the said emulsion polymerization on the conditions whose pHs are 1-5.