JPS6312885B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for grafting an unsaturated dicarboxylic acid compound onto a block copolymer containing a vinyl aromatic compound-conjugated diene compound block copolymer and a styrenic polymer, or on the block copolymer composition. . Styrene-butadiene block copolymer is a material that has recently been attracting attention, and those with a low styrene content are used in various fields as thermoplastic rubber, and those with a high styrene content are used as transparent impact-resistant styrenic resins. It is used. Attempts have been made to modify this type of styrene-butadiene block copolymer by maleation, etc. For example, JP-A-50-56427 discloses a method of maleating in the coexistence of rubber developing oil. Publication No. 52-123443 describes a method of maleating polyethylene together with polyethylene in a screw extruder in the presence of a radical initiator. However, all of the above-mentioned maleation methods are designed for very limited special applications and lack versatility. In particular, the method described in JP-A-50-56427 merely shows a method applicable only to pressure-sensitive adhesive applications that require a large amount of developing oil. On the other hand, the method disclosed in JP-A-52-123443 uses a radical initiator in the extruder, so it is excellent in terms of reaction conversion and productivity, but the compatibility of styrene-butadiene block copolymerization with polyethylene is poor. This is not a preferred method because it tends to cause lump gelation of the block copolymer, and it is not a preferred method since it requires a large amount of polyethylene to coexist. In general, the butadiene portion of a styrene-hebutadiene block copolymer is extremely prone to gelation, and therefore maleation in an extruder using a radical initiator has not reached an industrially satisfactory stage. The present invention provides an advantageous method for grafting unsaturated dicarboxylic acid compounds onto vinyl aromatic compound-conjugated diene compound block copolymers. That is, the gist of the present invention is that (a) the content of the vinyl aromatic compound is 5 to 95% by weight;
A block copolymer containing 10 to 100% by weight of a vinyl aromatic compound-conjugated diene compound block copolymer (b) 90 to 0% by weight of a styrene polymer or a block copolymer composition containing When carrying out a graft reaction with a saturated dicarboxylic acid compound, the graft reaction is carried out in the following manner: (1) temperature of the reaction zone: 150 to 250°C (2) in the presence of a radical initiator in an amount expressed by the following formula: D・C<0.5 where, D is the weight percent of the conjugated diene compound contained in the block copolymer or the block copolymer composition, and C is the amount of the radical initiator based on 100 parts by weight of the block copolymer or the block copolymer composition. Indicates parts by weight added. ] Further, (3) 0.001 to 5 parts by weight of at least one gelling stabilizer selected from phenolic, phosphorus, and amine stabilizers based on 100 parts by weight of the block copolymer or the block copolymer composition. (4) In the presence of an inhibitor, in an extruder, the amount of unsaturated dicarboxylic acid compound added is 0.05~
20% by weight (5) Production of a modified block copolymer or modified block copolymer composition characterized by obtaining a modified block copolymer or modified block copolymer composition having a toluene insoluble content of 1% by weight or less. It's a method. The vinyl aromatic compound-conjugated diene compound block copolymer (hereinafter referred to as "block copolymer composition") constituting component (a) of the block copolymer of the present invention or the block copolymer composition (hereinafter referred to as "block copolymer composition") "copolymer") comprises at least one polymer block mainly composed of a vinyl aromatic compound,
Preferably, it contains at least two or more polymer blocks mainly composed of a conjugated diene compound, and the weight ratio of the vinyl aromatic compound to the conjugated diene compound is limited to a composition range of 5/95 to 95/5. . In addition, in the polymer block mainly composed of a vinyl aromatic compound of the block copolymer, the weight ratio of the vinyl aromatic compound to the conjugated diene compound is
The composition range is limited to 100/0 to 60/40, preferably 100/0 to 80/20, and more preferably 100/0. The distribution of the conjugated diene compound, which is a minor component, in the molecular chain may be random, tapered (in which the monomer component increases or decreases along the molecular chain), partially block-like, or a combination thereof. On the other hand, in a polymer block mainly composed of a conjugated diene compound, the weight ratio of the vinyl aromatic compound and the conjugated diene compound is 0/100.
~40/60 composition range, preferably 0/60
It is 100-20/80. The distribution of the vinyl aromatic compound, which is a minor component, in the molecular chain may be random, tapered, partially block-like, or a combination thereof. Furthermore, when containing two or more polymer blocks mainly composed of vinyl aromatic compounds or two or more polymer blocks mainly composed of conjugated diene compounds, each block may have the same structure. However, different structures are also possible. As the vinyl aromatic compound constituting the block copolymer of the present invention, one or two of styrene, α-methylstyrene, vinyltoluene, etc.
Among them, styrene is the most preferred. Further, as the conjugated diene compound, one or more types are selected from butadiene, isoprene, 1,3-pentadiene, etc. Among them, butadiene or isoprene is the most preferable. Additionally, it is incorporated in the form of butadiene-isoprene copolymers. Especially when a small amount of isoprene is introduced into the butadiene unit,
Effective in preventing gelation under high shear and high temperatures. Further, the conjugated diene polymer block may be partially or entirely hydrogenated. Further, the block copolymer has a number average molecular weight of
The molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) is preferably within the range of 1.05 to 10. Furthermore, the molecular structure of the block copolymer may be linear, branched, radial, or a combination thereof. The block copolymer used in the present invention is usually produced by polymerizing a vinyl aromatic compound and a conjugated diene compound in an inert hydrocarbon solvent such as hexane, cyclohexane, benzene, or toluene using an organolithium compound such as butyllithium as a polymerization catalyst. , obtained by anionic block copolymerization. Also,
It is also possible to make a branched or radial block copolymer by reacting the block copolymer having a lithium active terminal obtained by the above method with a polyfunctional coupling agent such as carbon tetrachloride or silicon tetrachloride. be. In addition, any block copolymer obtained by any production method can be used as the substrate for the modified block copolymer of the present invention as long as it falls within the above-mentioned limits. The above block copolymers can be used not only in one type but also in combinations of two or more types. Examples of these combinations include styrene-butadiene block copolymers and styrene-isoprene block copolymers. combination, a combination of two or more types of styrene-butadiene block copolymers with different molecular weights, a combination of two or more types of styrene-butadiene block copolymers with different styrene contents, a block structure of styrene-butadiene, and a block structure of styrene-butadiene block copolymers. Examples include combinations of styrene-butadiene-styrene block copolymers with different structures, and others. Typical commercially available products of the above block copolymers include Solprene T (manufactured by Asahi Kasei Corporation), Tufprene A (manufactured by Asahi Kasei Corporation), Kraton 1102, 1107 (manufactured by Ciel Corporation), K-Resin (manufactured by Philips Corporation), and Clearene (manufactured by Philips Corporation). manufactured by Denki Kagaku Co., Ltd.). The styrenic polymer constituting component (b) of the block copolymer composition of the present invention includes general polystyrene with a molecular weight of 10,000 or more, preferably 30,000 or more, more preferably 100,000 or more, and impact resistance. It is selected from polystyrene and other copolymers of styrene and α-methylstyrene, acrylonitrile, etc.
Preferred is general purpose polystyrene. The weight ratio of component (a) and component (b) in the block copolymer composition of the present invention is (a)/(b)=100/0 to 10/
90 preferably 100/0 to 60/40, more preferably
Selected from 100/0. Examples of unsaturated dicarboxylic acid compounds used in the present invention include maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, crotonic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endo-
cis-bicyclo[2,2,1]-5-heptene 2,
3-dicarboxylic acids, etc., and their derivatives include acid anhydrides, esters, and esters of these carboxylic acids.
Examples include acid amides and dicarboxylic acid imides, but among these, dicarboxylic acid anhydrides are preferred, and maleic anhydride is particularly preferred. The unsaturated dicarboxylic acid compound added in the present invention is 0.05 to 30% by weight based on the block copolymer composition.
The content is preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight. The radical initiator used in the present invention is selected from organic peroxides, organic hydroperoxides, azo compounds, and the like. Some peroxides useful in this invention include dialkyl peroxides and diacyl peroxides. Dialkyl peroxide has the general structure R-OO
-R', in which R and R' are the same or different primary, secondary or tertiary alkyl groups, cycloalkyl groups, aralkyl groups or heterocyclic groups. Groups of peroxides suitable for use in the present invention include dicumyl peroxide, di-tert-butyl peroxide, tert-butylcumyl peroxide and 2,5-dimethyl-2,5-bis(tert-butyl peroxide). Contains oxy)hexane. Diacyl peroxide has the general structure RC(O)
OOC(O)R', where R and R' are the same or different alkyl, cycloalkyl, aralkyl, aryl or heterocyclic groups. Examples of some diacyl peroxides suitable for use in the present invention include dilauroyl peroxide, dibenzoyl peroxide, dicetyl peroxide, didecanoyl peroxide, di-(2,4-dichlorobenzoyl) peroxide. , diisononanoyl peroxide and 2-methylpentanoyl peroxide. Furthermore,
Other peroxides useful in the present invention include methyl ethyl ketone peroxide, cyclohexanone peroxide, and the like, along with particularly preferred peresters such as tert-butyl peroctoate and tert-butyl perbenzoate. Examples of hydroperoxides suitable for use in the present invention include tert-butyl hydroperoxide, cumyl hydroperoxide, 2,5
-dimethyl-2,5-dihydroperoxyhexane, p-methane hydroperoxide and diisopropylbenzene hydroperoxide. Examples of azo compounds that can be used in the present invention include diazoaminobenzene, N,N'-dichloroazodicarboxylic acid amide, azodicarboxylic acid diethyl ester, and 1-cyano-1-(tert-butylazo).
These include cyclohexanone and azobis(isobutyronitrile). The most preferred among these radical initiators are azo compounds. The amount of the radical initiator used in the present invention is determined under the condition that D.C<0.5 [where D is the weight percent of the conjugated diene compound contained in the block copolymer composition, and is 100% of the block copolymer composition. (indicates the parts by weight of the radical initiator added to parts by weight)]. Conditions other than these are undesirable because toluene insoluble matter increases. In the present invention, the antigelation agent added for the purpose of preventing gelation or discoloration is at least one type selected from phenol-based, phosphorus-based, and amine-based stabilizers. These additives are
Although it is effective alone, it is preferable to use two or three components in combination, and it is even more preferable to use a three-component combination consisting of a phenolic stabilizer, a phosphorus stabilizer, and another one-component stabilizer. .
Examples of phenolic stabilizers include 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis-(4-methyl-6-tert-butylphenol), 4,4-butylidenebis- (3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), n-octadecyl-β-(4'-hydroxy-
Examples include 3',5'-di-tert-butylphenyl) propionate. Examples of the phosphorus stabilizer include tri(nonylphenyl) phosphite, tridecyl phosphite, disterialyl pentaerythrityl diphosphite, and the like. In addition, other one-component compounds used together with phenolic stabilizers and phosphorus stabilizers include amine stabilizers such as phenyl-β-naphthylamine, β-naphthylamine, and phenothiazine, dilaurylthiodipropionate, distearylthio In addition to sulfur-based stabilizers such as dipropionate, dilauryl sulfide, and 2-mercaptobenzimidazole, 2-
It is also possible to use thiazole compounds such as metal salts of merptobenzothiazole, dibenzothiazyl disulfide, and 2-mercaptobenzothiazole. These stabilizers are used in block copolymer compositions.
0.001 to 5 parts by weight per 100 parts by weight, preferably
It is added in an amount of 0.05 to 2 parts by weight. However, it is not preferable to use a compound that reacts with the maleic acid compound to cause gelation. The graft reaction in the present invention is carried out in a single or multi-screw or multi-stage extruder, preferably a screw extruder. A Banbury mixer can also be used, but it is not preferred in terms of productivity. Among the operating conditions for the screw extruder preferred as the reactor of the present invention, regarding temperature, the temperature after the melt zone of the extruder (reaction zone) is 150 to 250°C.
℃, preferably selected from the range of 180 to 220℃. The most preferable grafting reaction conditions of the present invention are conditions in which the temperature of the reaction zone is 180 to 220°C and D.C<0.5 [where D is the weight of the conjugated diene compound contained in the block copolymer composition]. %,C
represents the parts by weight of the radical initiator added to 100 parts by weight of the block copolymer composition. The reaction temperature and the amount of the radical initiator and polystyrene polymer should be selected to meet these conditions. The most preferred grafting reaction conditions of the present invention are preferably carried out under an atmosphere of nitrogen or vacuum. In particular, in the area of supplying block copolymer compositions,
Alternatively, in the area where the unsaturated dicarboxylic acid compound is added, it is preferable to use a nitrogen atmosphere or a vacuum atmosphere. The reaction conditions in these extruders are important in preventing gelation and coloring of the resulting modified block copolymer composition. The block copolymer composition modified with a maleic acid compound obtained by the present invention contains 0.05 to 20% by weight, preferably 0.1 to 10% by weight of a maleic acid compound.
% by weight, more preferably 0.1 to 5% by weight. The ratio of the melt viscosity index of the modified block copolymer composition obtained in the present invention to the melt viscosity index of the block copolymer composition before modification is in the range of 0.025 to 2.0. If it is less than 0.025, the melt flow characteristics of the modified block copolymer composition will deteriorate, and if it is more than 2.0, the mechanical properties will be impaired. The toluene insoluble content of the modified block copolymer composition obtained in the present invention is 1% by weight or less, preferably,
It is 0.5% by weight or less. However, if the modified block copolymer composition is reversibly crosslinked with a metal salt or acid anhydride, the melt viscosity index or toluene insoluble content is measured after decomposing the reversible crosslinks by acid treatment, etc. shall be taken as a thing. The toluene insoluble content is the proportion (wt%) of the insoluble content remaining on the wire mesh when the modified block copolymer composition is dissolved in toluene and filtered through a 200 mesh wire mesh.
shows. Furthermore, in the modified block copolymer resin composition of the present invention, any inorganic or organic compound can be selected as an additive, such as a stabilizer, a tackifier, a filler, a lubricant, Also included are what are commonly referred to as flame retardants, colorants, crosslinkers or reagents. Mono- to trivalent metal compounds that can form ionic bonds with carboxylic acid groups are also useful as additives. Specific examples of uses of the modified block copolymer composition obtained by the method of the present invention include use as a polarized material in thermoplastic rubber applications such as shoe sole materials, or as polarized materials in impact-resistant styrene resin applications. sell. Examples 1 to 8 and Comparative Examples 1 to 4 Maleic anhydride and antigelation agent were added to the vinyl aromatic compound-conjugated diene block copolymer and styrene polymer, and these were mixed uniformly using a mixer. . This mixture was connected to a screw type extruder (single screw, screw diameter 40 mm, L/D=25, full flight type) under a nitrogen atmosphere, and a maleation reaction was carried out under the conditions shown below. . Extruder temperature cylinder C ₁ (12D from the screw tip)
200℃ Cylinder C ₂ (5D part from the screw tip)
200°C Die 200°C Screw rotation speed 35 rpm The obtained polymer was dried under reduced pressure at 120°C to obtain a maleated modified block copolymer composition. Table 1 shows the properties of the block copolymer and polystyrene used. Further, the maleation reaction conditions and results are shown in Table 2.

【table】

[Table] Weight% or less

[Table] Note 1) Titration with sodium methylate 2) 200 mesh residue

Claims (1)

[Scope of Claims] 1 (a) A vinyl aromatic compound-conjugated diene compound block copolymer having a vinyl aromatic compound content of 5 to 95% by weight (10 to 100% by weight) (b) A styrene polymer 90 When grafting an unsaturated dicarboxylic acid compound onto a block copolymer or a block copolymer composition containing ~0% by weight, the grafting reaction is carried out at a temperature of (1) reaction zone temperature of 150-250°C (2 ) In the presence of an added amount of a radical initiator represented by the following formula, D・C<0.5 [where D is the weight% of the conjugated diene compound contained in the block copolymer or the block copolymer composition, C represents the part by weight of the radical initiator added to 100 parts by weight of the block copolymer or the block copolymer composition. ] Further, (3) 0.001 to 5 parts by weight of at least one gelling stabilizer selected from phenolic, phosphorus, and amine stabilizers based on 100 parts by weight of the block copolymer or the block copolymer composition. (4) In the presence of an inhibitor, in an extruder, the amount of unsaturated dicarboxylic acid compound added is 0.05~
20% by weight (5) Production of a modified block copolymer or modified block copolymer composition characterized by obtaining a modified block copolymer or modified block copolymer composition having a toluene insoluble content of 1% by weight or less. Method. 2. The manufacturing method according to claim 1, wherein the grafting reaction is carried out in a nitrogen or vacuum atmosphere. 3. The manufacturing method according to claim 1, wherein the radical initiator is an azo compound. 4. The manufacturing method according to claim 1, wherein the radical initiator is benzoyl peroxide. 5. The manufacturing method according to claim 1, wherein the temperature of the reaction zone is 180 to 220°C.