JPH04314714A - Method for modifying polymer - Google Patents

Abstract

PURPOSE:To stabilize the reaction for modifying a block copolymer, such as a styrene-butadiene block copolymer, with an unsatd. carboxylic acid compd. CONSTITUTION:The modification reaction is conducted in the presence of 2,4-di- t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, a phenolic compd. selected from the group consisting of 2, 4-bis(alkylthio)-6-(3,5-di-t-butyl-4- hydroxyanilino)-1,3,5-triazine, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4- hydroxyphenyl)propionate], and 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4- hydroxybenzyl)benzene, and a phosphorus antioxidant. Thus, a modified polymer which is excellent in color tone and melt viscosity characteristics and has a low gel content is produced stably.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying a block copolymer obtained from a vinyl aromatic compound and a conjugated diene with a modifier selected from unsaturated carboxylic acids and derivatives thereof.

0002

BACKGROUND OF THE INVENTION Many attempts have been made to improve adhesive properties, green strength, etc. by modifying resins or rubbers with highly functional unsaturated carboxylic acid compounds, such as maleic acid compounds. For example, Japanese Patent Publication No. 55-13
No. 720 and JP-A-55-25315 disclose a method of maleating a block copolymer of butadiene and styrene in an organic solvent in the presence of a radical polymerization catalyst. However, in all of these methods, maleation occurs under the generation of radicals, so gelation of the resulting modified block copolymer is unavoidable, resulting in a significant deterioration of melt flow characteristics and appearance characteristics.

On the other hand, JP-A-55-38803 and JP-A-55-60511 disclose that a modification reaction is carried out under specific conditions in the absence of a radical initiator using a screw extruder. A method has been proposed to obtain a modified polymer with excellent melting properties and a low content insoluble in toluene.

[0004] Also, in Japanese Patent Publication No. 2-57805,
In order to suppress gelation of the block copolymer during modification, 2
-t-Butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl The modification reaction is carried out in the presence of certain phenolic antioxidants and phosphorus stabilizers such as acrylate. A method is proposed. Although the method disclosed in this publication is a considerable improvement over previous stabilization techniques, the color tone of the modified polymer was not necessarily good, and further improvements were required.

[0005]

[Problem to be Solved by the Invention] Under these circumstances, the present inventors have conducted intensive research on a method for obtaining a modified polymer that has excellent color tone and melting properties and contains less gel-like substances. As a result, the present invention was achieved.

[0006]

[Means for Solving the Problems] That is, the present invention provides a block copolymer having at least one vinyl aromatic hydrocarbon-based polymer segment and at least one conjugated diene-based polymer segment. (A) 2,4-di-t-amyl-6 when reacting with a modifier selected from unsaturated carboxylic acids and derivatives thereof.
-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, (B)
(I), (II) and (III) below

[0007]

[Chemical 2]

(In the above formula, R1 has 2 to 20 carbon atoms.
(C) is modified in the presence of a phosphorus antioxidant; Provided is a method for modifying a polymer characterized by carrying out a reaction.

The block copolymer used in the present invention has at least one vinyl aromatic hydrocarbon-based polymer segment and at least one conjugated diene-based polymer segment, It can be manufactured by various known methods. As a method for producing such a block copolymer, for example, Japanese Patent Publication No. 36-1928
6 Publication, Special Publication No. 43-17979, Special Publication No. 45-31951, Special Publication No. 46-324
Examples include the method described in Publication No. 15.

[0010] In the block copolymer used in the present invention, the polymer segment mainly composed of vinyl aromatic hydrocarbons refers to a homopolymer block of vinyl aromatic hydrocarbons and/or a vinyl aromatic hydrocarbon portion of 50% by weight. A copolymer block of a vinyl aromatic hydrocarbon and a conjugated diene containing 50% or more of a conjugated diene, and a polymer block mainly composed of a conjugated diene means a homopolymer block of a conjugated diene and/or a conjugated diene portion of 50% by weight or more. % or more of conjugated diene and vinyl aromatic hydrocarbon.

The conjugated diene that is a component of the block copolymer is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (i.e., isoprene). , 2,3-dimethyl-
1,3-butadiene, 1,3-pentadiene, 1,3-
Examples include hexadiene, but particularly common are 1,3-butadiene and isoprene. These conjugated dienes may be used alone or in combination of two or more.

Furthermore, examples of the vinyl aromatic hydrocarbon which is the other component of the block copolymer include styrene, o-
Methylstyrene, p-methylstyrene, p-tert-
Examples include butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, and among these, styrene is particularly commonly used. These vinyl aromatic hydrocarbons may be used alone or in a mixture of two or more.

The polymer to be modified in the present invention has at least one polymer segment mainly composed of vinyl aromatic hydrocarbon and at least one polymer segment mainly composed of conjugated diene. The block copolymer may be used alone, or it may be a mixture of such a block copolymer and a thermoplastic resin or a rubbery polymer.

Examples of thermoplastic resins that can be mixed with the block copolymer include the following. Polystyrene, such as polystyrene, impact-resistant rubber-modified styrene polymer, acrylonitrile/styrene copolymer, styrene/maleic anhydride copolymer, acrylonitrile/butadiene/styrene copolymer, methacrylate ester/butadiene/styrene copolymer resin;

[0015]
Polyethylene, a copolymer of ethylene and other copolymerizable monomers containing 50% by weight or more of ethylene moiety, such as ethylene/propylene copolymer, ethylene/vinyl acetate copolymer and its hydrolyzate, and ethylene/acrylic Acid ionomers or polyethylene resins such as chlorinated polyethylene; polypropylene, copolymers of propylene containing 50% by weight or more of propylene moieties and other copolymerizable monomers, such as propylene/ethylene copolymers and propylene/acrylics; Polypropylene resins such as ethyl acid copolymers or chlorinated polypropylene; Polybutene resins such as polybutene-1 and copolymers of butene-1 and other copolymerizable monomers;

Polyvinyl chloride, polyvinylidene chloride, vinyl chloride moiety and/or vinylidene chloride moiety
Polyvinyl chloride resins such as copolymers of vinyl chloride and/or vinylidene chloride and other copolymerizable monomers containing at least 50% by weight of vinyl acetate moieties;
Polyvinyl acetate-based resins such as copolymers of vinyl acetate and other copolymerizable monomers and their hydrolysates in an amount of at least % by weight;

Polymers of acrylic acid, acrylic esters, acrylic amide, methacrylic acid, methacrylic esters or methacrylic amide, and other copolymerizable monomers containing 50% by weight or more of these acrylic acid monomers. Polyacrylate resins such as copolymers;
Nitrile resins such as polymers of acrylonitrile and/or methacrylonitrile, copolymers with other copolymerizable monomers containing 50% by weight or more of these acrylonitrile monomers;

Linear polymers in which the structural units of the polymer are bonded by repeating amide group bonds, such as ring-opening polymers of ε-aminocaprolactam and ω-aminolaurolactam,
Polyamide resins such as condensation polymers of ε-aminoundecanoic acid and condensation polymers of hexamethylene diamine and dibasic acids such as adipic acid and sebacic acid; lines in which the constituent units of the polymer are bonded by repeating ester bonds polyester resins such as condensation polymers of dibasic acids such as phthalic acid and isophthalic acid or derivatives thereof and glycol components such as ethylene glycol, propylene glycol, butylene glycol; the structural units of the polymer are carbonate ester type. Linear polymers linked by repeating bonds, e.g. 4,4'-dihydroxydiphenylalkane, 4,4'
- A polycarbonate resin such as a polymer obtained by a reaction between a dihydroxy compound such as dihydroxydiphenyl sulfide and phosgene, or a polymer obtained by a transesterification reaction between the dihydroxy compound and diphenyl carbonate;

Polyphenylene ether resin or a grafted polyphenylene ether resin obtained by graft polymerizing a vinyl-substituted aromatic hydrocarbon to this resin; polyphenylene sulfide resin; polysulfone resins such as polyether sulfone and polyallylsulfone; polyoxymethylene, trioxane, etc. Polyacetal resin such as copolymer with alkylene oxide; Thermoplastic polyurethane resin obtained by polyaddition reaction of diisocyanate component and glycol component; Transpolybutadiene, 1,2
-Polybutadiene resin such as polybutadiene; Polyarylate resin, which is a polycondensation polymer consisting of bisphenol A and phthalic acid components; Has a structure in which part or all of the hydrogen in a chain hydrocarbon polymer compound is substituted with fluorine Fluororesin; polyoxybenzoyl resin; polyimide resin.

Rubbery polymers that can be mixed with the block copolymer include polybutadiene, polyisoprene, styrene/butadiene copolymer, butadiene/acrylonitrile copolymer, ethylene/propylene copolymer,
Examples include ethylene/propylene/diene copolymer, silicone rubber, epichlorohydrin rubber, acrylic rubber, and ethylene/vinyl acetate copolymer.

When using a mixture of a block copolymer and a thermoplastic resin or a rubbery polymer, the mixing ratio of the two (weight ratio of block copolymer/thermoplastic resin or rubbery polymer) is generally 99. The range is preferably from about /1 to 3/97, more preferably from about 97/3 to 5/95. Note that these may be mixed in advance or may be mixed in the modification reaction apparatus during the modification reaction.

Examples of unsaturated carboxylic acids and derivatives thereof that can be used as modifiers in the present invention include maleic acid, maleic anhydride, maleic ester, maleic amide, maleic imide, fumaric acid, fumaric ester, fumaric acid amide, fumaric acid imide, itaconic acid,
Itaconic anhydride, itaconic ester, itaconic acid amide, itaconic acid imide, halogenated maleic acid, halogenated maleic anhydride, halogenated maleic ester,
Halogenated maleic acid amide, halogenated maleic acid imide, cis-4-cyclohexene-1,2-dicarboxylic acid, cis-4-cyclohexene-1,2-dicarboxylic acid anhydride, cis-4-cyclohexene-1,2-dicarboxylic acid acid ester, cis-4-cyclohexene-1,2-dicarboxylic acid amide, cis-4-cyclohexene-1,2-
Dicarboxylic acid imide, endo-cis-bicyclo(2,2
,1)-5-heptene-2,3-dicarboxylic acid, anhydrous endo-cis-bicyclo(2,2,1)-5-heptene-
2,3-dicarboxylic acid, endo-cis-bicyclo(2,
2,1)-5-heptene-2,3-dicarboxylic acid ester, endo-cis-bicyclo(2,2,1)-5-heptene-2,3-dicarboxylic acid amide, endo-cis-bicyclo(2, 2,1)-5-heptene-2,3-dicarboxylic acid imide, acrylic acid, acrylic ester,
Examples include acrylic acid amide, methacrylic acid, methacrylic ester, and methacrylic acid amide.

These modifiers can be used alone or in combination of two or more. Among these modifiers, unsaturated dicarboxylic acids or derivatives thereof are preferred, and maleic anhydride is particularly preferred. The amount of the modifier selected from these unsaturated carboxylic acids and derivatives thereof is generally 0.00 parts by weight per 100 parts by weight of the block copolymer or the mixture of the block copolymer and the thermoplastic resin or rubbery polymer. 1~
About 100 parts by weight is preferable. If the amount of denaturing agent is too small, the denaturing effect will be small; conversely, if the amount of denaturing agent is too large,
This is not preferable because it becomes complicated to remove the unreacted modifier from the modified product and the homopolymer of the modifier itself becomes mixed.

In the present invention, the temperature at which the block copolymer or the mixture of the block copolymer and the thermoplastic resin or rubbery polymer is reacted with the modifier is 180 to 32°C.
The temperature is preferably about 0°C. If the reaction temperature is less than 180°C, the reaction rate of the modifier will be low and the modification effect will be reduced, which is not preferable. On the other hand, if the reaction temperature exceeds 320° C., the color tone and melting characteristics will deteriorate, and a large amount of gel-like substances that are insoluble in solvents such as toluene will be produced, which is not preferable.

In order to suppress the formation of gel-like substances during the modification reaction, it is preferable to carry out the modification reaction in the absence of a radical initiator such as a peroxide or an azo compound. Within the range that does not involve generation,
Operations such as increasing the reaction rate of the modifier using a small amount of radical initiator may also be performed.

In the present invention, component (A) 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-
2-Hydroxyphenyl)ethyl]phenyl acrylate and the phenolic compound selected from the formulas (I), (II) and (III) of the component (B) are:
(A) and (B) relative to 100 parts by weight of the block copolymer, or when using a mixture of the block copolymer and a thermoplastic resin or rubbery polymer, relative to a total of 100 parts by weight of both. It is preferable to use the total amount of about 0.1 to 1 part by weight. If the amount is less than 0.1 part by weight, the effect of suppressing the formation of gel-like substances during the modification reaction will not be sufficient, and even if it is added in excess of 1 part by weight, the effect will not be commensurate with that amount. Since no improvement can be expected, it is economically disadvantageous.

In the above formula (I), the alkyl group represented by R1 has 2 to 20 carbon atoms, and preferably has about 4 to 18 carbon atoms. Among the phenolic compounds represented by formula (I), those in which R1 is octyl, i.e., 2,4-bis(n-octylthio)-6-(3,5-di-t-butyl-4-hydroxy Anilino)-1,3,5-triazine is preferred. The chemical names of the phenolic compounds represented by formulas (II) and (III) are pentaerythrityl, respectively.
Tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], and 1,3,5
-trimethyl-2,4,6-tris(3,5-di-t-
butyl-4-hydroxybenzyl)benzene.

In the present invention, the phosphorus antioxidant is preferably used in an amount of about 0.1 to 1 part by weight based on 100 parts by weight of the block copolymer or mixture. If the amount is less than 0.1 part by weight, the effect of suppressing the formation of gel-like substances during the modification reaction will not be sufficient, and even if it is added in excess of 1 part by weight, the effect will not improve commensurately. It is economically disadvantageous because it cannot be expected.

[0029] The phosphorus-based antioxidant referred to herein is an organic compound that has at least one phosphorus atom in its molecule and has antioxidant ability. Examples of preferable phosphorus antioxidants include the following. Tris(nonylphenyl) Phosphite, distearyl Pentadierythritol Diphosphite, Tris(2,4-di-t-butylphenyl) Phosphite, tetratridecyl 4,4'-Butylidenebis(3-methyl-6-t) -butylphenyl)
Diphosphite, bis(2,4-di-t-butylphenyl) Pentaerythritol Diphosphite, tetrakis(2,4-di-t-butylphenyl)
4,4'-biphenylene diphosphonite, bis(2
-t-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-t-butylphenyl) octyl
phosphite, 2,2'-ethylidene bis(4,6
-di-t-butylphenyl) fluorophosphonite, bis(2,4,6-tri-t-butylphenyl)
Pentaerythritol diphosphite.

In the present invention, other additives may be added as necessary, such as other phenolic antioxidants, sulfur antioxidants, ultraviolet absorbers, hindered amine light stabilizers, lubricants, pigments, flame retardants, and foaming agents. Agents, reinforcing agents, inorganic fillers, etc. can be added to the composition at the stage of the modification reaction, or at any stage before or after the modification reaction. Specific examples of these optional additives are shown below.

The above formulas (I), (II) and (III)
Examples of phenolic antioxidants other than the compounds represented by are as follows. n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, triethylene glycol bis[3-(3-t-butyl-4-hydroxy-
5-methylphenyl)propionate], 3,9-bis[2-{3-(3-t-butyl-4-hydroxy-5-
methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, 2,2'-ethylidenebis(4
, 6-di-t-butylphenol), tris(3,5-
di-t-butyl-4-hydroxybenzyl) isocyanurate.

Examples of sulfur-based antioxidants include the following. Dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, lauryl stearyl 3,3'
-thiodipropionate.

[0033] Examples of the ultraviolet absorber include the following. 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, bis(5-benzoyl-4-hydroxy-2
-methoxyphenyl)methane, 2,2',4,4'-tetrahydroxybenzophenone, 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-[2
-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, 2-(3-t-butyl-2-hydroxy-5
-methylphenyl)-5-chlorobenzotriazole,
2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(2-hydroxy-5-
t-octylphenyl)benzotriazole, 2-(3
,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2-(3, 5-di-t-butyl-2-
hydroxyphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], poly( 3-11) (ethylene glycol) and methyl 3-[3-(2H-benzotriazol-2-yl)-5-t-butyl-4-
Condensate with hydroxyphenyl]propionate, 2-
Ethylhexyl 3-[3-t-butyl-5-(5-
Chloro-2H-benzotriazol-2-yl)-4-
Hydroxyphenyl]propionate, octyl 3
-[3-t-butyl-5-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]
Propionate, methyl 3-[3-t-butyl-5
-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate, 3-[
3-t-butyl-5-(5-chloro-2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionic acid, 2,2'-methylenebis[4-t-butyl-
6-(2H-benzotriazol-2-yl)phenol].

Examples of hindered amine light stabilizers include the following. Bis (2, 2, 6,
6-tetramethyl-4-piperidyl) sebacate,
Polycondensate of dimethyl succinate and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine, poly[(6-morpholino-1,3,5-triazine-2, 4-diyl) {(2,
2,6,6-tetramethyl-4-piperidyl)imino}
Hexamethylene {(2,2,6,6-tetramethyl-4
-piperidyl)imino], bis(1,2,2,6,6
-pentamethyl-4-piperidyl) 2-(3,5-
di-t-butyl-4-hydroxybenzyl)-2-butylmalonate, 4-[3-(3,5-di-t-butyl-
4-hydroxyphenyl)propionyloxy]-1-
[2-{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy}ethyl]-2,2,
6,6-tetramethylpiperidine, bis(1,2,2,
6,6-pentamethyl-4-piperidyl) decanedioate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, poly[{6-( 1,1,3,3-tetramethylbutyl)imino-1,3,5-triazine-
2,4-diyl}{(2,2,6,6-tetramethyl-
4-piperidyl)imino}hexamethylene {(2,2,
6,6-tetramethyl-4-piperidyl)imino},
1,2,3,4-butanetetracarboxylic acid and 1,2
, mixed esterified product with 2,6,6-pentamethyl-4-piperidinol and 1-tridecanol, 1,2,
3,4-butanetetracarboxylic acid and 2,2,6,6
- Mixed esterified product of tetramethyl-4-piperidinol and 1-tridecanol, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9- Bis(2-
hydroxy-1,1-dimethylethyl)-2,4,8,
Mixed ester of 10-tetraoxaspiro[5.5]undecane, 1,2,3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1
-dimethylethyl)-2,4,8,10-tetraoxaspiro[5.5]mixed ester with undecane, N
, N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 1,2-dibromoethane polycondensate, 2-methyl-2-(2,2,
6,6-tetramethyl-4-piperidyl)amino-N-
(2,2,6,6-tetramethyl-4-piperidyl)propionamide, N,N',4,7-tetrakis[4,
6-bis{N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino}-1,3,5-triazin-2-yl]-4,7-diazadecane-1, 10
-diamine, N,N',4-tris[4,6-bis{N
-butyl-N-(2,2,6,6-tetramethyl-4-
piperidyl)amino}-1,3,5-triazine-2-
yl]-4,7-diazadecane-1,10-diamine,
Bis(1-acryloyl-2,2,6,6-tetramethyl-4-piperidyl)2,2-bis(3,5-di-t-
Butyl-4-hydroxybenzyl)malonate, N,N
',4,7-tetrakis[4,6-bis{N-butyl-
N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino}-1,3,5-triazin-2-yl]
-4,7-diazadecane-1,10-diamine, N,N
',4-Tris[4,6-bis{N-butyl-N-(1
,2,2,6,6-pentamethyl-4-piperidyl)amino}-1,3,5-triazin-2-yl]-4,7
-diazadecane-1,10-diamine, bis(2,2,
6,6-tetramethyl-4-piperidyl) succinate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, tetrakis(
1,2,2,6,6-pentamethyl-4-piperidyl)
1,2,3,4-butanetetracarboxylate.

[0035] The modification reaction of the polymer according to the present invention is preferably carried out under melt-kneading in the absence of an organic solvent, but it may be carried out in a state where the polymer is dissolved in an organic solvent if necessary. Examples of the melt-kneading method include methods using general mixers such as international mixers, co-kneaders, continuous kneaders with twin-screw rotors, and single-screw, twin-screw or multi-screw extruders. In particular, a method using an extruder is preferred from the viewpoint of continuous production. In the melt-kneading method using an extruder, the average residence time in the extruder is generally about 10 to 1000 seconds. If the average residence time is too short, problems such as a low reaction rate or non-uniform reaction will occur, while if the average residence time is too long, the formation of gel-like substances will become noticeable, so this is not preferred. do not have.

Further, in the present invention, the amount of unreacted modifier remaining in the modified polymer after the modification reaction is 1 part by weight or less, preferably 0.5 part by weight or less per 100 parts by weight of the modified polymer. It is preferable to do this in order to obtain a modified polymer with excellent color tone. For this purpose, it is recommended to use an extruder equipped with a ventable device and carry out the modification reaction while removing unreacted modifier from the vent section by means such as reduced pressure.

It is also possible to carry out the modification reaction in the presence of a basic inorganic compound to obtain an ionic crosslinked modified polymer. The basic inorganic compound used in this case is generally a monovalent, divalent or trivalent metal compound, and examples thereof include compounds such as sodium, potassium, magnesium, calcium, zinc, and aluminum. Suitable examples of these metal compounds include hydroxides, alcoholates, carboxylates and oxides. Among these, magnesium hydroxide, magnesium oxide, calcium hydroxide, aluminum hydroxide, mixtures thereof, and mixtures mainly composed of these can be preferably used. When using these basic inorganic compounds, the amount added is 0.00 parts per 100 parts by weight of the block copolymer or mixture.
01 to 5 parts by weight.

[0038]

[Examples] The present invention will be explained in more detail with reference to Examples below, but these Examples are intended to show preferred specific examples and are not intended to limit the scope of the present invention. Note that % and parts in the examples are based on weight unless otherwise specified.

The test stabilizers used in the examples are as follows, and are indicated by the respective symbols below. A: 2,4-di-t-amyl-6-[1-(3
,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate I: 2,4-bis(n-octylthio)-6-
(3,5-di-t-butyl-4-hydroxyanilino)
-1,3,5-triazine II: pentaerythrityl tetrakis [3
-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] III: 1,3,5-trimethyl-2,4,6-
Tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene AO-1: 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methyl Phenyl acrylate P-1: Tris(2,4-di-t-butylphenyl) Phosphite P-2: Tetratridecyl 4,4'-butylidenebis(3-methyl-6-t-butylphenyl)
diphosphite

Example 1 After blending 100 parts of a styrene/butadiene block copolymer with an MI value of 3 g/10 min at 190°C, 2 parts of maleic anhydride, and a stabilizer in the amounts shown in Table 1, The maleation reaction was carried out at 240° C. using a single screw extruder with a diameter of 40 mm. The average residence time in the extruder is approximately 12
It was 0 seconds. Unreacted maleic anhydride is removed under reduced pressure through a vent installed near the tip of the extruder, and the amount of maleic anhydride remaining in the modified polymer is reduced.
The content was set to 0.2% or less. The amount of maleic anhydride added to the obtained modified block copolymer was in the range of 0.8 to 1.2% throughout each composition in Table 1. The melt viscosity retention, toluene insoluble content, and color tone of the modified block copolymer thus obtained were measured or evaluated by the following methods, and the results are shown in Table 1. A similar maleic anhydride addition reaction was also attempted for a system that did not use the test stabilizer, but gelation occurred during the modification reaction and a modified polymer could not be obtained, so the following measurements and evaluations were not possible. Ta.

Melt viscosity retention: Using a melt indexer (manufactured by Takara Kogyo Co., Ltd.), the melt flow rate at 200° C. of the polymer before and after modification was measured. From these values, the melt viscosity retention rate was determined according to the following formula. The styrene/butadiene block copolymer is crosslinked by heat during modification, resulting in a decrease in fluidity, so a higher melt viscosity retention means better thermal stability.

Toluene-insoluble matter: After dissolving 5 g of the modified polymer in 200 g of toluene, it was filtered through a 100-mesh wire mesh, and the toluene-insoluble matter remaining on the wire mesh was vacuum-dried at 90° C. for 2 hours, and the weight after drying was measured. The percentage of toluene-insoluble matter was determined. This means that the less gel-like substances that are insoluble in toluene are produced, the better the thermal stability is.

Color tone: The b value of the obtained modified polymer pellets was measured, and the quality of the color tone was judged according to the following criteria. The larger the b value, the greater the apparent yellowness. ◎ : b value less than 30 ○ : b value 30 or more but less than 35 △ : b
Value 35 or more and less than 40×: b value 40 or more

[0044]

[0045]

Effects of the Invention According to the present invention, a method for stably producing a polymer modified with an unsaturated carboxylic acid or a derivative thereof can be provided, and the modified polymer obtained has excellent color tone and melt viscosity characteristics. In addition, there is less inclusion of gel-like substances. Therefore, the modified polymer obtained by the present invention is
By taking advantage of the fact that it is modified with unsaturated carboxylic acid or its derivatives, it can be used as a modifier for various thermoplastic resins and thermosetting resins, materials for footwear, materials for adhesives and adhesives, asphalt modifiers, It can be used as a material for power cables, a modifier for vulcanized rubber, etc.

Claims (2)

[Claims] Claim 1: A block copolymer having at least one vinyl aromatic hydrocarbon-based polymer segment and at least one conjugated diene-based polymer segment, which contains an unsaturated carboxylic acid and a derivative thereof. (A) 2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-
2-Hydroxyphenyl)ethyl]phenyl acrylate, (B) of the following formulas (I), (II) and (III
) [Formula 1] (In the above formula, R1 represents an alkyl group having 2 to 20 carbon atoms, and R2 represents 3,5-di-t-butyl-4-hydroxyphenyl). A method for modifying a polymer, comprising carrying out a modification reaction in the presence of a phosphorus-based antioxidant and (C) a phosphorus-based antioxidant. Claim 2: Polymer 100 containing the block copolymer
Per part by weight, (A) acrylate and (B) phenol compound are present in a total of 0.1 to 1 part by weight, and (C) phosphorus antioxidant is present in 0.1 to 1 part by weight. The method according to claim 1.