JP2002338605A - Method for manufacturing epoxidized diene polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for economically manufacturing an epoxidized diene polymer having excellent heat stability. SOLUTION: An epoxidized diene polymer is manufactured by epoxidizing a diene polymer having a sphere-converted particle size of 0.05-20 mm dispersed and/or suspended in a water medium in the presence of a phenolic stabilizer and/or a phosphorus-type stabilizer, and, optionally, an antiblocking agent in the form of powdery particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an epoxidized diene-based polymer used for paints, resin modifiers, rubber modifiers, adhesives and the like. More specifically, in epoxidizing the double bond in the molecular chain of the diene polymer, the diene polymer in an aqueous solvent, in the presence of a heat stabilizer,
This is a method for producing an epoxidized diene polymer having excellent thermal stability by performing epoxidation in a suspended state.

[0002]

2. Description of the Related Art Conventionally, the following method has been known as a method for oxidizing a diene polymer to be epoxidized into an epoxidized diene polymer. (1) Hydrogen peroxide and a lower carboxylic acid such as formic acid or acetic acid are reacted in advance to produce a percarboxylic acid, and a percarboxylic acid as an epoxidizing agent is added to the reaction system, and the presence or absence of a solvent is added. Method of performing epoxidation reaction below. (2) A method of epoxidation using hydrogen peroxide in the presence of a catalyst such as an osmium salt, tungstic acid and a solvent. Each of the methods (1) and (2) is characterized by dissolving a diene polymer to be epoxidized in a solvent in order to efficiently perform an epoxidation reaction. However,
The steps of dissolving in a solvent, washing with water to remove carboxylic acids as a by-product after the epoxidation reaction, and removing the solvent are complicated, which makes collection of the product extremely difficult. In particular, when the organic polymer to be epoxidized is a rubber polymer, the epoxidized product has adhesiveness, blocking of the product immediately after production, difficulty in handling the product, deterioration in workability, blocking during storage. There are problems such as. for that reason,
After epoxidation modification, in some cases, it cannot be commercialized as powders, crumbs, or pellets, and may be in a veil form, and its use as a modifier is limited.

The inventors of the present invention have proposed many methods for producing an epoxidized diene polymer. For example, Japanese Patent Application Laid-Open No. Hei 8-120022 discloses that (1) a diene polymer or a partially hydrogenated product thereof. Mixing an organic solvent to obtain an organic solvent slurry or an organic solution of the polymer; (2) epoxidizing an unsaturated carbon bond present in the diene polymer using an epoxidizing agent; (3) (4) neutralizing the epoxidation reaction solution and / or washing with water; (4) adding a solution of the epoxidized block copolymer having a polymer concentration of 5 to 50% by weight to a boiling point of an organic solvent in the presence of a surfactant; Or, when the solvent and water are azeotropic, the azeotropic temperature is equal to or higher than 120 ° C.
A step of stripping at a temperature below to obtain a slurry in which the polymer is dispersed in water; (5) dehydrating the crumb of the epoxidized block copolymer containing water obtained above to reduce the water content to 1 to 30% by weight. %, And (6) a method of drying the epoxidized block copolymer obtained above to reduce the water content to 1% by weight or less to obtain an epoxidized diene polymer. Japanese Patent Application Laid-Open No. 9-60479 discloses a manufacturing method using a screw extruder-type squeezing and dewatering machine in the drying step (6).
In Japanese Patent Application Publication No. 12 (1999), a method for recovering an epoxidized block copolymer is characterized in that the epoxidized block copolymer solution obtained in the step (3) is supplied to an evaporator and the organic solvent is directly removed by evaporation. Has been proposed. Also, Japanese Patent Application Laid-Open
JP-A-104709 proposes a production method for improving the gel content by defining the acid value of a product.

However, all of these methods are inventions relating to a method of producing an epoxidized block copolymer by a solution method in which a raw material polymer is dissolved in a solvent and then epoxidized, and handling of a high viscosity slurry is extremely difficult. . Furthermore,
The epoxidized block copolymers obtained by these methods have a relatively low softening point, such that pellets of the copolymer may block each other at the surface during manufacture, processing, transportation, or use, or may be interlinked. However, there is a problem that they are firmly adhered to each other, which hinders handling. As an improvement method,
Japanese Patent Application Laid-Open No. 9-67502 proposes adding an antiblocking agent to the obtained epoxidized copolymer in a later step. Also, Japanese Patent Application Laid-Open No. 9-20861
No. 7 proposes a chemically modified diene-based polymer composition and a method for producing the composition by epoxy-modifying a polymer in a fine particle state of 0.05 to 10 μm in water as a method for producing the composition. This method is a production method as a composition, and does not mention the point of recovery of the epoxy-modified polymer, the point of improvement of product blocking, and the like. Japanese Patent Application Laid-Open No. 10-298232 proposes epoxidation in an aqueous dispersion, but only provides an aqueous dispersion in which only the surface of polymer particles is specifically epoxidized. Neither of these publications mentions the thermal stability of the obtained epoxidized product alone.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for economically producing an epoxidized diene polymer having excellent thermal stability.

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, when epoxidation was carried out in an aqueous dispersion system, epoxidation was carried out in the presence of a heat stabilizer. By doing so, it has been found that a polymer having excellent thermal stability can be produced. Specifically, in a system in which a diene polymer is dispersed or suspended in a solid state such as a pellet or powder in an aqueous solvent in the presence of a phenol stabilizer and / or a phosphorus stabilizer and powder particles, Epoxidation using acetic acid and a reaction accelerator, separation and recovery in a solid state, and a solvent removal step are carried out, whereby an epoxidized diene polymer having excellent thermal stability can be obtained. The present invention has been completed based on these facts.

That is, according to the present invention, a diene polymer having a sphere-converted particle diameter in the range of 0.05 to 20 mm is dispersed and / or suspended in an aqueous medium in the presence of a phenol stabilizer and / or a phosphorus stabilizer. Provided is a method for producing an epoxidized diene-based polymer which is epoxidized in a turbid state. The diene polymer is at least one selected from the group consisting of a butadiene polymer, a styrene-butadiene copolymer, an isoprene polymer, a styrene-isoprene copolymer, an acrylonitrile-butadiene copolymer, and a partially hydride thereof. A method for producing the epoxidized diene-based polymer of the invention is provided. The present invention provides a method for producing the epoxidized diene-based polymer according to the present invention, wherein peroxyacetic acid or another percarboxylic acid derived using hydrogen peroxide is used as an epoxidizing agent.
The present invention provides a method for producing the epoxidized diene-based polymer of the present invention, wherein the epoxidizing agent is peracetic acid. The present invention provides a method for producing an epoxidized diene polymer using a solvent for accelerating an epoxidation reaction. The method for producing an epoxidized diene polymer according to the invention, wherein the epoxidation reaction accelerating solvent is at least one solvent selected from the group consisting of cyclohexane, toluene, xylene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone, and chloroform. provide. The present invention provides a method for producing an epoxidized diene-based polymer, wherein the SP (solubility parameter) value of the epoxidation reaction accelerating solvent is 10 or less.

Further, according to the present invention, the total amount of the phenol-based stabilizer and / or the phosphorus-based stabilizer is not more than 1%.
There is provided a method for producing the epoxidized diene-based polymer according to any one of the above-mentioned inventions, which is 0.05 to 5 parts by weight based on 00 parts by weight. The present invention provides a method for producing the epoxidized diene-based polymer according to any one of the above-mentioned inventions, using an anti-blocking agent for powder particles. The present invention provides a method for producing an epoxidized diene-based polymer in which powder particles are inorganic particles. The present invention provides a method for producing an epoxidized diene-based polymer in which the inorganic particles are talc or silica. A first step of epoxidizing a diene-based polymer in an aqueous medium in the presence of an epoxidizing agent or a solvent for promoting the epoxidation reaction with the epoxidizing agent to form an epoxidized diene-based polymer; Production of the epoxidized diene-based polymer of the invention comprising a second step for washing or neutralization and water washing of the combined substance, and a third step optionally provided for removing the solvent for accelerating the epoxidation reaction. Provide a way. The second step is
The present invention provides a method for producing the epoxidized diene-based polymer of the present invention, which comprises a solid-liquid separation operation for separating the polymer supplied to the third step. The method for producing an epoxidized diene-based polymer according to the invention is provided in which the solvent is removed in the third step, and the polymer obtained in the second step is dried while maintaining the granular shape. The method for producing the epoxidized diene-based polymer of the present invention, wherein the solvent removal in the third step is performed by a kneading evaporator. The method for producing the epoxidized diene-based polymer according to any one of the above-mentioned inventions, wherein the oxirane oxygen concentration in the epoxidized diene-based polymer is 0.3 to 5.0% by weight. A method for producing the epoxidized diene-based polymer according to any one of the above-mentioned inventions, wherein the obtained epoxidized diene-based polymer has a gel content of 2% by weight or less. Further, the present invention provides the method for producing an epoxidized diene-based polymer according to any one of the above-mentioned inventions, wherein the gel content of the epoxidized diene-based polymer after heating is less than 2.5 times the gel content before heating. I do.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The diene-based polymer to be epoxidized in the present invention is a homopolymer of butadiene, a homopolymer of isoprene, a copolymer of butadiene and another monomer or a copolymer of isoprene and another monomer. Become. Examples of other monomers to be copolymerized with butadiene or isoprene include other conjugated dienes and vinyl compounds. As other conjugated dienes to be copolymerized with butadiene, for example,
Isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,
Examples thereof include 3-octadiene and phenyl-1,3-butadiene. These other conjugated dienes can be used alone or in combination of two or more. Other conjugated dienes to be copolymerized with isoprene include, for example, butadiene, 1,3-pentadiene,
3-dimethyl-1,3-butadiene, piperylene, 3-
Butyl-1,3-octadiene, phenyl-1,3-butadiene and the like can be mentioned. Butadiene,
Isoprene is preferred. These other conjugated dienes can be used alone or in combination of two or more.

Further, as the vinyl compound copolymerized with butadiene or isoprene, for example, styrene, α-
Methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-tertiary butyl styrene, o-methoxy styrene, m-methoxy styrene, p
-Vinyl aromatic compounds such as methoxystyrene, divinylbenzene, 1,1-diphenylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i- (meth) acrylate Propyl, n-butyl (meth) acrylate, i-butyl (meth) acrylate, sec-butyl (meth) acrylate,
Unsaturated monocarboxylic esters such as t-butyl (meth) acrylate, lauryl (meth) acrylate, methyl crotonate, ethyl crotonate, methyl cinnamate and ethyl cinnamate; 2,2,2-tri Fluoroethyl (meth) acrylate, 2,2,3,3,3-pentafluoropropyl (meth) acrylate, 2,2,3,3,4,4
Fluoroalkyl (meth) acrylates such as 4-heptafluorobutyl (meth) acrylate;

3- (trimethylsiloxanyldimethylsilyl) propyl (meth) acrylate, 3- [tris (trimethylsiloxanyl) silyl] propyl (meth)
(Meth) acryloyl group-containing siloxanyl compounds such as acrylate and di- [3- (meth) acryloylpropyl] dimethylsilyl ether; ethylene glycol;
2-propanediol, 1,3-propanediol,
Mono- or di- (meth) acrylates of alkylene glycols such as 1,6-hexanediol; 2-methoxyethylene (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxypropyl (meth)
Alkoxyalkyl (meth) acrylates such as acrylate and 3-ethoxypropyl (meth) acrylate;
Cyanoalkyl (meth) acrylates such as 2-cyanoethyl (meth) acrylate and 3-cyanopropyl (meth) acrylate; glycerin, 1,2,4-butanetriol, pentaerythritol, trimethylolalkane (the carbon number of the alkane is For example, 3 such as 1-3)
Oligo (meth) acrylates such as di-, tri- or tetra (meth) acrylate of a polyhydric alcohol having a valency of 3 or more;

(Meth) acrylonitrile, α-chloroacrylonitrile, vinyl cyanide compounds such as vinylidene cyanide; (meth) acrylamide, N-methylol (meth) acrylamide, N, N′-methylenebis (meth) acrylamide, N, N '-Ethylenebis (meth)
Unsaturated amides such as acrylamide; hydroxyalkyl (meth) such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate
Acrylates; hydroxyalkyl esters of unsaturated monocarboxylic acids such as 2-hydroxyethyl crotonate, 2-hydroxypropyl crotonate, 2-hydroxyethyl cinnamate and 2-hydroxypropyl cinnamate;
Unsaturated alcohols such as (meth) allyl alcohol;
Unsaturated monocarboxylic acids such as (meth) acrylic acid, crotonic acid and cinnamic acid; (anhydride) maleic acid, fumaric acid,
(Anhydride) unsaturated polycarboxylic acids (anhydrides) such as itaconic acid and citraconic acid; mono- or di-esters of the unsaturated polycarboxylic acids; (meth) allyl glycidyl ether, glycidyl (meth) acrylate and the like In addition to the epoxy group-containing unsaturated compound, vinyl chloride, vinyl acetate, sodium isoprenesulfonate, dicyclopentadiene, ethylidene norbornene and the like can be mentioned.
Of these, styrene-based vinyl compounds are particularly preferred. These vinyl compounds can be used alone or in combination of two or more.

In the present invention, the copolymer of butadiene and the copolymer of isoprene may be a random copolymer or a block copolymer. Examples of the polymer to be epoxidized in the present invention include a homopolymer of butadiene, a random copolymer of butadiene and styrene, a random copolymer of butadiene and (meth) acrylonitrile, and a block copolymer of butadiene and styrene. , Random copolymer of isoprene and styrene, isoprene and (meth)
Preferred are a random copolymer with acrylonitrile, a block copolymer of isoprene and styrene, and a copolymer of butadiene and isoprene. The copolymer of butadiene and isoprene may optionally contain a vinyl compound such as styrene or (meth) acrylonitrile.

The content of butadiene in the copolymer of butadiene and the content of isoprene in the copolymer of isoprene are usually 0.5 to 99.5% by weight, and more preferably 1 to 99.5% by weight.
It is preferably from 95 to 95% by weight, especially from 5 to 90% by weight. Also,
In the copolymer of butadiene and isoprene, the content of butadiene is usually 0.5 to 99.5% by weight, preferably 1 to 95% by weight, particularly preferably 5 to 90% by weight, and the content of isoprene is preferably , Usually 0.5 to 99.5% by weight,
Furthermore, it is 5 to 99% by weight, especially 10 to 95% by weight,
The content of the optionally used vinyl compound is usually
0-99% by weight, more preferably 0-95% by weight, especially 0-90% by weight
% By weight is preferred. The weight average molecular weight of the homopolymer or copolymer of butadiene and the copolymer of isoprene in the present invention is preferably from 1,000 to 5,000,000.
00, more preferably 5,000 to 500,000.

When the copolymer is a block copolymer, the composition of the copolymer may be, for example, polystyrene-polybutadiene block copolymer, polystyrene-polybutadiene-polystyrene block copolymer (SBS), polystyrene-
Polyisoprene-polystyrene block copolymer (SI
S), polyacrylonitrile-polybutadiene block copolymer (NBR) and the like. Further, as for these diene copolymers, a partially hydrogenated product obtained by partially hydrogenating a diene component may be used. The structure of the molecule itself of these block copolymers may be any of linear, branched and radial structures. The average molecular weight of the block copolymer is not particularly limited, but is preferably such that it does not dissolve in low molecular weight organic solvents. There is no particular limitation on the terminal group of the resin or rubber-based polymer to be the diene-based polymer to be epoxidized. Among these diene polymers, butadiene polymers and styrene-
It is preferably at least one diene polymer selected from the group consisting of butadiene copolymers, isoprene polymers, styrene-isoprene copolymers, acrylonitrile-butadiene copolymers and partially hydrides thereof.

The resin or rubber polymer to be the diene polymer to be epoxidized has a particle diameter in terms of sphere in the reaction system of an aqueous medium in the presence of a phenol stabilizer and / or a phosphorus stabilizer. 0.05-20 mm, preferably 0.07
It needs to be dispersed and / or suspended in a range of 20 mm, more preferably 0.1-20 mm. The epoxidation-targeted diene-based polymer being dispersed or suspended at the reaction temperature means that the epoxidation-targeted diene-based polymer is in a solid state such as powder or granules throughout the reaction,
It means that at the reaction temperature, the diene-based polymer does not exhibit a liquid or paste-like powder or granules, or a linked body in which they are arbitrarily combined. When they are in a liquid or paste state, they tend to coalesce and stirring becomes difficult. The spherical equivalent particle size of the diene polymer to be epoxidized is 0.05 m
If it is less than m, solid-liquid separation is particularly difficult in handling, and if it exceeds 20 mm, the surface area becomes small, and the progress of epoxidation which proceeds from the surface, which is a feature of the present invention, is not preferred. As long as the spherical equivalent particle diameter of the diene polymer to be epoxidized is within the above range, it may be in the form of a commercially available pellet. In order to carry out the epoxidation reaction efficiently, it may be pulverized to increase the surface area of the diene polymer to be epoxidized. The method of pulverization may be a method of pulverization with a usual pulverizer, but when the diene-based polymer to be epoxidized is a rubber-based polymer, it is preferable to perform pulverization by a freeze-pulverization method. Here, the sphere-converted particle diameter is defined as the diameter of a sphere having the same volume as the average volume of the diene polymer to be epoxidized. In the production method of the present invention, the epoxidation reaction is carried out in an aqueous medium, but the epoxidation reaction is promoted by using an organic solvent as described below to infiltrate the epoxidizing agent into the dispersed particles of the diene polymer to be epoxidized. It can also be used as a solvent for use.

In the production method of the present invention, at the time of the epoxidation reaction, a phenol stabilizer and / or a phosphorus stabilizer are present in the reaction system in order to improve the thermal stability of the product epoxidized diene polymer. Representative examples of phenolic stabilizers include tetrakis (methylene-3- (3 ′, 5′-di-
tert-butyl-4′-hydroxyphenyl) propionate) methane, 1,3,5-trimethyl-2,4
6-tris (3,5-di-tert-butyl-4′-hydroxybenzyl) benzene, 2,6-di-tert-
Butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert-butylphenol, 2,4-
Bis- (n-octylthio) -6- (4-hydroxy-
3-5-di-tert-butylanilino) -1,3,5
-Triazine, octadecyl-3- (3,5-di-te)
rt-butyl-4-hydroxyphenyl) propionate, triethylene glycol-bis (3- (3-ter
t-butyl-5-methyl-4-hydroxyphenyl) propionate), 1,3,5-tris- (4-tert
-Butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2′-methylenebis- (4-
Methyl-6-tert-butylphenol), 3,9-
Bis (2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy)-
1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 2,6-di-te
rt-butyl-4-ethylphenol, butylated hydroxyanisole, 2,2′-dihydroxy-3,3′-
Dicyclohexyl-5,5'-dimethyl-diphenylmethane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4 '
-Butylidenebis-6-tert-butyl m-cresol, bis (3-cyclohexyl-2-hydroxy-5methylphenyl) methane, 2,2'-methylenebis- (4
-Ethyl-6-tert-butylphenol), 1,1
-Mevis- (2'-methyl-4'-hydroxy-5'-
tert-butylphenyl) butane and the like. These phenolic stabilizers can be used in combination of two or more. Representative examples of the phosphorus-based stabilizer include trisnonylphenyl phosphite, tris (2,5-di-tert-butylphenyl) phosphite, tris (2-di-tert-butylphenyl) phosphite, tris (2 , 4-bis (1,1-dimethylpropyl) phenyl) phosphite and the like. These phosphorus-based stabilizers can be used in combination of two or more. These phenol-type and phosphorus-based stabilizers may be used in combination or may be used alone. The amount of the stabilizer used is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the diene polymer to be epoxidized. By adding these stabilizers at the time of the epoxidation reaction, it is possible to uniformly disperse them in the epoxidized diene polymer, and one of the operations of post-addition at the time of extrusion or the like becomes unnecessary.

The manufacturing method of the present invention is as follows. A first step of performing an epoxidation reaction with a peroxide in an aqueous solvent in the presence of a diene polymer and a heat stabilizer;
In the case where a water washing step or a neutralization and water washing step is used as the second step and an organic solvent is used as the reaction promoting solvent in the first step, a solvent removal step may be provided as the third step. In the second step, the polymer that has been subjected to the water-washing step or the neutralization and water-washing steps is separated into a polymer by solid-liquid separation and supplied to the third step. Thereafter, in the third step, while maintaining the polymer shape obtained in the second step, drying and / or
Alternatively, this is a production method in which the epoxidized diene-based polymer is recovered by drying with a kneading evaporator. A feature of the present invention is that a heat stabilizer is used at the time of epoxidation and is uniformly penetrated into a diene polymer, so that the obtained epoxidized diene polymer has excellent heat stability.

The epoxidation reaction solvent used for carrying out the epoxidation reaction to cause the epoxidation reaction of the diene polymer to be epoxidized in a dispersed and / or suspended state is carried out under the epoxidation conditions. It is desirable that the solvent be a solvent that dissolves and swells the diene-based polymer or penetrates the diene-based polymer. The choice of the organic solvent depends on the type of the diene polymer to be epoxidized and the reaction conditions for the epoxidation, but linear and branched hydrocarbons such as hexane and octane, and their alkyl-substituted derivatives; cyclohexane, cyclohexane Alicyclic hydrocarbons such as heptane, and alkyl-substituted derivatives thereof; aromatic hydrocarbons such as benzene, naphthalene, toluene, and xylene; and alkyl-substituted aromatic hydrocarbons; methyl acetate;
Aliphatic carboxylic acid esters such as ethyl acetate; halogenated hydrocarbons such as chloroform; and the like.
Among these, from the viewpoint of dissolving and using a peroxide as an epoxidizing agent, from the viewpoints of solubility of a diene polymer to be epoxidized and easy recovery of an organic solvent thereafter,
Cyclohexane, ethyl acetate, chloroform, toluene, benzene, xylene, hexane, tetrahydrofuran and the like are preferred, and one or more mixed solvent systems can be used.

These organic solvents are selected according to the diene polymer to be epoxidized. Organic solvents are
It has the function of dissolving the peroxide and heat stabilizer, which are epoxidizing agents, or penetrating and transporting the diene polymer in the solid state to the inside, and fixing the epoxidation and the stabilizer to the inside. As a selection criterion, it is preferable to select an organic solvent capable of dissolving or swelling the diene polymer to be epoxidized or penetrating the diene polymer, and having a solubility parameter value of 10 or less. An organic solvent having a solubility parameter value of more than 10 has a small ability to dissolve or swell in a diene polymer to be epoxidized or penetrate into a diene polymer to be epoxidized, and does not function as a reaction accelerator. When an organic solvent is used as the reaction-promoting solvent, the amount is preferably from 0.5 to 100, more preferably from 0.5 to 75 parts by weight per 100 parts by weight of the diene polymer to be epoxidized. Water is preferably from 50 to 1,000, more preferably from 100 to 1,000 parts by weight per 100 parts by weight of the diene polymer to be epoxidized. The same proportion of water is used when no organic solvent is used.

In carrying out the epoxidation reaction, an anti-blocking agent may be used. Powder particles are used as the antiblocking agent. The above-mentioned reaction promoting solvent dissolves the diene polymer to be epoxidized, swells, or penetrates into the diene polymer, so that depending on the amount used, blocking between polymer particles occurs, which is a feature of the present invention. The reaction in the aqueous dispersion cannot proceed.
Therefore, an anti-blocking agent is used to avoid the blocking between polymer particles and allow the reaction to proceed. As the powder particles, inorganic particles are preferable. As inorganic particles,
The type, size, shape, etc. are not particularly limited. For example, particles of a poorly water-soluble or water-insoluble inorganic compound such as calcium carbonate, zeolite, silica, mica, talc, magnesium oxide, and magnesium hydroxide are exemplified. Of these inorganic particles, talc and silica are more preferred because they have a small amount of anti-blocking effect. The use ratio of the antiblocking agent is 0.01 to 5, more preferably 0.05 to 5 parts by weight per 100 parts by weight of the diene polymer to be epoxidized.
3 parts by weight are preferred. The average particle size of the antiblocking agent is preferably from 0.1 to 100 μm, and more preferably from 0.1 to 50 μm because a small amount has an antiblocking effect.

Examples of the peroxide used as the epoxidizing agent include percarboxylic compounds such as formic acid, peracetic acid and perpropionic acid. Epoxidation with peroxides derived with hydrogen peroxide is also possible. Among them, peracetic acid is preferable because it efficiently promotes epoxidation. When using a percarboxylic acid as an epoxidizing agent, it is preferable to use the percarboxylic acid dissolved in a solvent. As the solvent for the percarboxylic acids, hydrocarbons such as hexane, organic acid esters such as ethyl acetate,
Examples include aromatic hydrocarbons such as toluene. These solvents have the same effect on the epoxidation reaction as the above-mentioned reaction accelerator, and penetrate into the interior of the diene polymer to be epoxidized to promote the epoxidation reaction. Therefore, it is desirable to use these solvents. .

In a system using a peroxide derived from hydrogen peroxide, hydrogen peroxide and a lower carboxylic acid such as formic acid or acetic acid are reacted in advance to produce a percarboxylic acid, and this percarboxylic acid is used in the reaction system. There is a method of adding an epoxidizing agent and performing an epoxidation reaction, or a method of performing epoxidation using hydrogen peroxide in the presence of a catalyst such as an osmium salt or tungstic acid and a solvent. Solvents that can be used in this case are
Same as listed above.

In the epoxidation by the production method of the present invention, the oxirane oxygen concentration of the obtained epoxidized product is as follows:
0.3 to 5.0% by weight, more preferably 0.3 to 4.5% by weight. The oxirane oxygen concentration can be adjusted by changing the amount of double bonds in the diene polymer to be epoxidized and the reaction molar ratio with the epoxidizing agent. This reaction molar ratio varies depending on the level of the oxirane oxygen concentration of the obtained epoxidized product, but the reaction molar ratio of the amount of double bonds contained in the diene-based polymer to be epoxidized and the amount of pure peroxide,
It can be selected in the range of 1.0 to 3.0, and particularly 1.1 to 3.0.
It is preferable to select in the range of 2.5.

The reaction temperature for epoxidizing the diene polymer to be epoxidized according to the production method of the present invention depends on the type of the diene polymer to be epoxidized, the size of the surface area, the type of the solvent, the type of the epoxidizing agent and Although it depends on the amount and the reaction time, it is preferable to select within the range of 10 to 70 ° C. When the reaction temperature is lower than 10 ° C., the reaction rate is too low to be practical. Conversely, when the temperature is 70 ° C. or higher, the peroxide self-decomposes significantly, which is not preferable. Further, there is a problem that the dissolution of the surface of the epoxidized diene-based polymer by the organic solvent proceeds to cause blocking. A more preferred reaction temperature is 3
It is in the range of 0-60 ° C. The reaction pressure is usually at atmospheric pressure, but may be slightly reduced or slightly increased.

The reaction time for epoxidizing the diene polymer to be epoxidized according to the production method of the present invention depends on the type of the diene polymer to be epoxidized, the size of the surface area, the type of the solvent, and the type of the epoxidizing agent. Although it varies depending on the amount and the reaction temperature, it can be usually selected in the range of 1 to 24 hours.
When the reaction time is less than 1 hour, the conversion of the double bond is low and is not practical. On the other hand, when the reaction time is 24 hours or more, for example, when peracetic acid is used, a side reaction of the organic polymer is caused. Is generated, which causes a decrease in yield, which is not preferable.

According to the production method of the present invention, the reaction solution after the epoxidation reaction is in a state where the product epoxidized diene polymer is dispersed or suspended in a water solvent in a solid state.
It is obtained as a suspension in which an organic solvent or carboxylic acid is dissolved in the solvent. In order to separate and recover the solid epoxidized product from the suspension, a method such as filtration or centrifugation may be used. The separated and recovered epoxidized product in the form of a solid is washed with water to remove a solvent, carboxylic acid and the like attached to the surface. Neutralization treatment and water washing treatment are performed as necessary. The aqueous alkaline solution used for neutralization includes lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, calcium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium acetate, An aqueous solution such as potassium acetate or ammonia water is used. Next, the obtained product is dried and commercialized. The drying here may be a method of removing water and the like by direct heating after desolvation by an indirect heating method such as a steam stripping method, and at least one of a vacuum dryer, a hot air dryer, a kneading evaporator and the like. The organic solvent is directly removed from the polymer obtained by various kinds of dryers to reduce the water content to less than 1% by weight. In the method of the present invention, various additives can be added to the polymer according to the purpose. For example, softeners such as oils, plasticizers, antistatic agents, lubricants, ultraviolet absorbers, flame retardants, pigments,
Inorganic fillers, reinforcing agents such as organic and inorganic fibers, carbon black, and other thermoplastic resins can be used as additives. In addition, it is preferable to add these additives before putting them in the drying step.

The epoxidized diene-based polymer obtained by the method of the present invention has a gel content of 2% by weight or less, and more preferably 0.1% by weight or less.
The content of 2% by weight or less is preferable in that the appearance (surface state) of the final product using the epoxidized diene-based polymer becomes good. As a measure of the heat resistance of the epoxidized diene polymer, the gel content after heating under predetermined conditions is preferably less than 2.5 times the original gel content, more preferably 0 to less than 2 times. . If the gel content is within the specified range, it can be said that the thermal stability has been improved. Also, after the same heating, even if the strand is further pulled by an extruder and the surface state thereof is visually observed, no foreign matter is recognized,
This means that the thermal stability is good. When using an anti-blocking agent for powder particles such as inorganic particles, the surface layer of diene polymer particles such as epoxidized pellets obtained by the present invention, 0.01 to the entire particle. 5% by weight of the powder may be attached. The epoxidized diene polymer particles may contain an unreacted diene polymer that has not been epoxidized in the epoxidation reaction at the center. The obtained epoxidized diene polymer can be used as various molded products such as sheets, films, injection molded products of various shapes, hollow molded products, etc., as well as modifiers, adhesives and adhesives for various thermoplastic resins. Material, asphalt modifier, home appliances, automobile parts, industrial parts, household goods, toys and the like.

[0028]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following description unless it exceeds the gist. In the following description example,
“Parts” and “%” are both based on weight. Various measurements were performed by the methods described below. (1) Oxirane oxygen concentration: Measured according to ASTM-1652. (2) Gel content: about 0.1 g of the dried epoxidized diene copolymer was added to 10 ml of toluene, and the mixture was stirred and dissolved at 25 ° C. for 3 hours. Then, the solution was passed through a 200-mesh wire net and passed through the wire net. The weight of insoluble matter which was not dried was measured at 120 ° C. for 2 hours, and the resulting weight was shown as a percentage by weight. (3) Gel content after heating: The solvent insoluble content after the dried epoxidized diene-based copolymer was left in an oven at 180 ° C. for 30 minutes (in air) was measured. This measurement result was used as one measure of thermal stability. If the gel content after heating is less than 2.5 times the original gel content, the thermal stability is considered to be almost good. (4) Surface state of the epoxidized diene copolymer after heating: using pellets heated under the same heating conditions as in (3) above, using a melt indexer (heating temperature 180 ° C., heating melting time 5 minutes, load A linear strand having a diameter of about 1 mm was extruded from a 5 kg die having a diameter of 1 mm), and the surface thereof was visually observed. ：: surface smooth, ×: surface bumpy. (5) Spherical particle size: The volume of 5 g of the dried diene-based copolymer particles to be epoxidized is measured by weighing it in distilled water, and the average volume per particle is determined. This is a value obtained by determining the diameter of a sphere having a volume.

Example 1 A block copolymer of polystyrene-polybutadiene-polystyrene (SBS) was placed in a three-liter, four-necked round bottom flask equipped with a stirrer, a thermometer, a dropping funnel and a reflux condenser. Synthetic Rubber Co., Ltd.
Product name: TR2000 @ 300 g (sphere-converted particle size 3.
5 g), 600 g of water, 1.5 g of a phenolic heat stabilizer (manufactured by Ciba Specialty Chemicals, trade name: Irganox 1010) and talc (talc MW HS-T manufactured by Hayashi Kasei Co., Ltd., average particle size: 2.7 μm) 0.6 g of each was charged, mixed well by stirring, and SBS was dispersed. The temperature inside the flask was raised to 40 ° C.
100 g of an ethyl acetate (SP = 8.9) solution was continuously dropped, and epoxidation was performed at 40 ° C. for 5 hours with stirring.
The reaction proceeded without blocking between the pellets. After the solid was recovered from the reaction solution after the reaction by filtration, the solid was washed with deionized water. Water and remaining solvent were removed from the collected solid by a vent-type kneading extruder to obtain 302 g of epoxidized SBS. The obtained epoxidized SBS had a gel content of 0.02% by weight and an oxirane oxygen concentration of 1.5% by weight. Further, the gel content after heating was 0.04% by weight, and the obtained epoxidized pellets were drawn on strands after heating, and the surface state was ○.

Example 2 The same four-necked round bottom flask used in Example 1 was charged with a copolymer of polystyrene-polybutadiene-polystyrene (SBS) {manufactured by Asahi Kasei Corporation; Converted particle size 3.0
mm), water 600 g, phenolic heat stabilizer (manufactured by Ciba Specialty Chemicals: Irganox 1)
010) 1.5 g and talc (Talc M manufactured by Hayashi Kasei Co., Ltd.)
(W HS-T) 0.6g was charged, stirred and mixed well to disperse SBS. Temperature inside flask is 40 ℃
And 30% of peracetic acid in ethyl acetate 100
g was continuously added dropwise, and epoxidation was performed at 40 ° C. for 6 hours with stirring. The reaction proceeded without blocking between the pellets. After the solid was recovered from the reaction solution after the reaction by filtration, the solid was washed with deionized water. Water and remaining solvent were removed from the collected solid by a vent-type kneading extruder to obtain 300 g of epoxidized SBS.
The resulting epoxidized SBS has a gel content of 0.1.
02% by weight and oxirane oxygen concentration was 1.5% by weight. Further, the gel content after heating was 0.04% by weight, and the obtained epoxidized pellets were drawn on strands after heating, and the surface state was ○.

Example 3 In the same four-necked round bottom flask used in Example 1, a copolymer of polystyrene-polybutadiene-polystyrene (SBS) (manufactured by Asahi Kasei Corporation; trade name: Tufprene 125) 300 g (sphere) Converted particle size 3.0
mm), water 600 g, phenolic heat stabilizer (manufactured by Ciba Specialty Chemicals: Irganox 1)
010) 3.0 g and talc (Talc M manufactured by Hayashi Kasei Co., Ltd.)
(W HS-T) 0.6g was charged, stirred and mixed well to disperse SBS. Temperature inside flask is 40 ℃
And 30% of peracetic acid in ethyl acetate 100
g was continuously added dropwise, and epoxidation was performed at 40 ° C. for 5 hours with stirring. The reaction proceeded without blocking between the pellets. After the solid was recovered from the reaction solution after the reaction by filtration, the solid was washed with deionized water. Water and remaining solvent were removed from the collected solid with a vented kneading extruder to obtain 300 g of epoxidized SBS. The resulting epoxidized SBS has a gel content of 0.02
% By weight, and the oxirane oxygen concentration was 1.5% by weight.
The gel content after heating was 0.02% by weight, and the obtained epoxidized pellets were drawn on strands after heating, and the surface state was ○.

Example 4 A copolymer of polystyrene-polybutadiene-polystyrene (SBS) was placed in the same four-necked round bottom flask used in Example 1 {Nippon Synthetic Rubber Co., Ltd.
Product name: TR2000 @ 300 g (sphere-converted particle size 3.
5 mm), 600 g of water, 3.0 g of a phenolic heat stabilizer (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals) and 0.6 g of talc (talc MW HS-T, manufactured by Hayashi Kasei Co., Ltd.), respectively. Stir and mix well to disperse SBS. Temperature inside flask is 40
At 30 ° C., and 10% ethyl acetate solution of 30% peracetic acid.
0 g was continuously added dropwise, and epoxidation was performed at 40 ° C. for 5 hours with stirring. The reaction proceeded without blocking between the pellets. After the solid was recovered from the reaction solution after the reaction by filtration, the solid was washed with deionized water. Water and remaining solvent were removed from the collected solid with a vented kneading extruder to obtain 300 g of epoxidized SBS. The resulting epoxidized SBS has a gel content of 0.0
2% by weight and oxirane oxygen concentration was 1.5% by weight. The gel content after heating was 0.02% by weight, and the obtained epoxidized pellets were drawn on strands after heating, and the surface state was ○.

Comparative Example 1 In Example 1, the reaction and recovery were carried out under the same conditions without using a phenolic heat stabilizer, to obtain 300 g of epoxidized SBS. The obtained epoxidized SBS had a gel content of 0.10% by weight and an oxirane oxygen concentration of 1.5% by weight. The gel content after heating was 1.0% by weight, and the obtained epoxidized pellets were drawn on strands after heating, and the surface state was x.

Comparative Example 2 In Example 2, the reaction and recovery were carried out under the same conditions without using a phenolic heat stabilizer, to obtain 300 g of epoxidized SBS. The obtained epoxidized SBS had a gel content of 0.12% by weight and an oxirane oxygen concentration of 1.5% by weight. Further, the gel content after heating was 0.35% by weight, and the obtained epoxidized pellets were drawn on a strand after heating, and the surface state was x.

[0035]

According to the present invention, an epoxidized diene-based polymer which is less likely to generate gel due to heating and has excellent heat stability is provided.
For example, epoxidize pellet raw material as it is,
Stabilizers can also be included, and kneading of stabilizers by kneading is unnecessary, and the raw material is used as an organic solution,
Compared with the method of epoxidation, it can be obtained by a method that is more economical, such as reducing the energy cost of dissolving in a solvent and recovering the solvent.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshihiro Otsuka 4-13-5-305 Kuba, Otake City, Hiroshima Prefecture F-term (reference) 4J100 AB02Q AM02Q AS02P AS03P BC53H CA01 CA04 CA31 HA29 HA61 JA01 JA03

Claims (18)

[Claims] A sphere-based particle diameter of 0.05 to 2 in an aqueous medium in the presence of a phenol stabilizer and / or a phosphorus stabilizer.
A method for producing an epoxidized diene polymer, comprising epoxidizing a diene polymer in a range of 0 mm in a dispersed and / or suspended state. 2. The diene polymer is a butadiene polymer,
A styrene-butadiene copolymer, an isoprene polymer, a styrene-isoprene copolymer, an acrylonitrile-butadiene copolymer, and at least one selected from the group consisting of hydrogenated products thereof. 2. The method for producing the epoxidized diene polymer according to 1. 3. The epoxidized diene-based polymer according to claim 1, wherein peracetic acid or another percarboxylic acid derived using hydrogen peroxide is used as an epoxidizing agent. Method. 4. The method for producing an epoxidized diene polymer according to claim 3, wherein the epoxidizing agent is peracetic acid. 5. The method for producing an epoxidized diene polymer according to claim 1, wherein a solvent for accelerating the epoxidation reaction is used. 6. The epoxidation according to claim 5, wherein the epoxidation reaction promoting solvent is at least one solvent selected from the group consisting of cyclohexane, toluene, xylene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone and chloroform. A method for producing a diene polymer. 7. The method for producing an epoxidized diene polymer according to claim 6, wherein the SP (solubility parameter) value of the solvent for promoting the epoxidation reaction is 10 or less. 8. The method according to claim 1, wherein the total amount of the phenol stabilizer and / or the phosphorus stabilizer is 0.05 to 5 parts by weight based on 100 parts by weight of the diene polymer. 8. The method for producing an epoxidized diene-based polymer according to any one of items 1 to 7. 9. The method for producing an epoxidized diene-based polymer according to claim 1, wherein an anti-blocking agent for powder particles is used. 10. The method for producing an epoxidized diene polymer according to claim 9, wherein the powder particles are inorganic particles. 11. The method for producing an epoxidized diene-based polymer according to claim 10, wherein the inorganic particles are talc or silica. 12. A first step of epoxidizing a diene polymer in an aqueous medium in the presence of an epoxidizing agent or a solvent for accelerating an epoxidation reaction with the epoxidizing agent to form an epoxidized diene polymer, A second step for washing or neutralizing and washing the epoxidized diene-based polymer with water, and a third step optionally provided for removing a solvent for accelerating the epoxidation reaction. Item 4. The method for producing an epoxidized diene polymer according to Item 1. 13. The method for producing an epoxidized diene polymer according to claim 12, wherein the second step includes a solid-liquid separation operation for separating the polymer supplied to the third step. 14. The method for producing an epoxidized diene polymer according to claim 12, wherein removing the solvent in the third step includes drying while maintaining the granular shape of the polymer obtained in the second step. 15. The method for producing an epoxidized diene polymer according to claim 12, wherein the solvent removal in the third step is performed by a kneading evaporator. 16. An oxirane oxygen concentration in the epoxidized diene polymer is from 0.3 to 5.0% by weight.
5. The method for producing an epoxidized diene-based polymer according to any one of 5. 17. The method for producing an epoxidized diene polymer according to claim 1, wherein the gel content of the obtained epoxidized diene polymer is 2% by weight or less. 18. The gel content of the epoxidized diene polymer after heating in an oven at 180 ° C. for 30 minutes (in air) is less than 2.5 times the gel content before heating.
8. The method for producing an epoxidized diene polymer according to any one of 7.