JPS6338378B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition. Conventionally, among block copolymers consisting of a styrene polymer block and a conjugated diene polymer block,
Resinous materials with high styrene content are as transparent as polystyrene homopolymers and have better impact resistance than polystyrene homopolymers, making them ideal for applications that require both transparency and impact resistance. Used as a preferred material. However, since the block copolymer contains butadiene, its rigidity and strength are inferior to that of polystyrene homopolymer, and although its impact resistance is superior to that of polystyrene homopolymer,
It has drawbacks such as being far inferior to high impact polystyrene. Various methods have been studied to improve these drawbacks, but the reduction in rigidity and strength due to copolymerization of butadiene has been considered to be a very fundamental problem that is difficult to solve. In addition, methods to improve impact resistance include increasing the butadiene content in the block copolymer and adding small amounts of high-impact polystyrene, but in the former case, the rigidity and strength decrease further. However, the latter poses another problem: reduced transparency. As described above, it is extremely difficult to produce a styrene-butadiene block copolymer that maintains the excellent transparency, rigidity, and strength of polystyrene homopolymer, and has better impact resistance than polystyrene homopolymer. It was considered. The present inventors have made extensive studies to produce a styrene-butadiene block copolymer having the above-mentioned excellent characteristics, and have completed the present invention based on a concept and knowledge completely different from those of the prior art. That is, the present invention provides the following formula: (A-B) _n or B(-A-B) _n or A(-B-A) _n or B-A(-A-B) _o (wherein A is a A polymer block mainly composed of diene, B represents a polymer block mainly composed of styrene, the content of conjugated diene in the copolymer is at least 3% by weight and less than 40% by weight, and n is 2. In the above, m is an integer of 1 or more.) A block copolymer consisting of a styrene polymer block and a conjugated diene polymer block with a molecular weight of 10,000 to 400,000, or a combination of these block copolymers and polystyrene. 100 parts by weight of a mixture of HR _3-a SiX _a (wherein R is an alkyl group, an allyl group, or a vinyl group, and X is an alkoxy group, an acyloxy group, an oxime group, or a substituted amino group) Represents a decomposable organic group, a is 2 or 3 It is a thermoplastic elastomer composition that can be made to have a high molecular weight or be crosslinked by. The silane-added block copolymer composition of the present invention maintains the excellent processability of the block copolymer before reacting with silane, so it can be injection-molded under normal processing conditions for block copolymer resins. Molding,
It is possible to mold sheets, films, and blow molded products, and after molding, when the molded product comes into contact with moisture, a polymerization reaction or a crosslinking reaction can occur, so the rigidity and impact resistance are reduced after the reaction. The oil resistance and oil resistance are improved, while the original excellent transparency is maintained. The content of the present invention will be specifically explained below. The block copolymer consisting of a styrene polymer block and a conjugated diene polymer block as the main raw materials used in the present invention is preferably one represented by the following general formula or a mixture thereof. (A-B) _n or B (-A-B) _n or A (-B-A) _n or B-A (-A-B) _o In the above formula, A is a polymer block mainly composed of a conjugated diene. , B represents a block mainly made of styrene. A may contain a small amount of styrene, and B may contain a small amount of butadiene or α-methylstyrene. The structure of the block copolymer includes a complete block copolymer, a gradually decreasing block copolymer, and the like. Further, the molecular weights of each A in the formula do not need to be the same, and the same applies to B. Further, in the formula, A and B may have branched polymer chains. Said B-A(-A-
B) The block copolymer represented by _o is a so-called radial block copolymer or star block copolymer, and the living block copolymer represented by B-A is combined with a polyfunctional coupling agent such as a polyhalide or a tetrachloride. It is manufactured by coupling with silicon or the like. The content of conjugated diene in the block copolymer is at least 3% by weight and less than 40% by weight,
Preferably it is 5% by weight or more and 30% by weight or less.
If it is less than 3% by weight, no impact resistance improvement effect will be substantially observed, and if it is more than 40% by weight, the rigidity will be low, making it undesirable as a resin. The conjugated diene used in the present invention includes 1,
These include 3-butadiene, isoprene, and 1,3-pentadiene. The molecular weight of the block copolymer of the present invention is from 10,000 to 400,000, preferably from 30,000 to 200,000. In the above formula, n represents an integer of 2 or more, and m represents an integer of 1 or more. Therefore, block copolymers having at least one block A and at least one block B are included in the present invention. The block copolymer of the present invention can be used, for example, in
No. 53-15958, Special Patent Application No. 143841 (1972), Special Publication No. 143841 (1977)
No. 31951, Japanese Patent Publication No. 1973-2423, Japanese Patent Publication No. 1977-99594
No., JP-A-49-130990, JP-A-48-20038,
It can be manufactured by the method shown in Japanese Patent Publication No. 48-4106. The silane compound used in the present invention has one hydrogen directly bonded to silicon and at least two hydrolyzable organic groups, and has the general formula HR _3-a SiX _a (a=2 or 3). If there are two or more hydrogens directly bonded to silicon, they will crosslink during the addition reaction. In the above formula, R includes alkyl groups such as methyl and ethyl groups, allyl groups such as phenyl groups, and vinyl groups, and X includes alkoxy groups such as methoxy, ethoxy, and butoxy groups, such as formyloxy and acetoxy groups or acyloxy groups such as propionoxy groups, oxime groups such as -
ON=C( _CH3 ) ₂ , _-ON = _OCH3C2H5 and _-ON
=C( _{C6H5 ) 2} or substituted amino groups such as alkynoamino and arylamino groups such as _-NHCH3 , _{-NHC2H5 and -NH} ( _C6H5 )
A hydrolyzable organic group selected from The most preferred silanes are monomethyldiethoxysilane,
These are monomethyldimethoxysilane, triethoxysilane, and trimethoxysilane. The proportion of silane used depends in part on the reaction conditions and in part on the extent to which the block copolymer is modified. The actual proportions may vary over a wide range, for example from 0.1 parts to 10 parts by weight per 100 parts by weight of block copolymer. However, it is generally preferred to use from 0.5 parts by weight to 5 parts by weight. The block copolymer containing the above double bond,
To react a silane compound having one hydrogen atom directly bonded to a silicon atom in one molecule and add the silane compound to the double bond. Both raw materials may be heated and mixed in a solvent or in the absence of a solvent. The heating temperature at this time is 60 to 200°C, preferably 80 to 160°C. Suitable solvents when carried out in the presence of a solvent include, for example, hydrocarbon solvents such as toluene, n-hexane, cyclohexane, di-n-hexane, etc.
- There are ethers such as butyl ether and ethylene glycol, dimethyl ether. In addition, in the case of no solvent, the reaction can be carried out in a Banbury, kneader, or extruder while thoroughly mixing both raw materials. Furthermore, in carrying out this reaction, it has conventionally been advantageous to use known platinum or a platinum compound as an addition reaction catalyst between a compound having an aliphatic double bond and a compound having an Si-H bond. Examples of such catalysts include solid platinum supported on a carrier such as platinum black, alumina, or silica, a complex of chloroplatinic acid and olefin, and a 2-ethylhexanol-modified chloroplatinic acid solution. . The adduct of block copolymer and silane obtained by the above method of the present invention is molded by conventional extrusion, injection molding, etc., and then exposed to moisture in the presence of a silanol condensation catalyst to increase the molecular weight or crosslink it. It can be reacted. Although atmospheric moisture is sufficient for the reaction to proceed, the rate of crosslinking can be improved if desired by using an artificially humid atmosphere, immersion in liquid water, and appropriately elevated temperatures. It can be improved by leaning. Silanol condensation catalysts that can be used in the present invention include organotin compounds such as dibutyltin dilaurate, dibutyltin diacetate and dibutyltin dioctoate. The silanol condensation catalyst can be mixed before, during or after the reaction of the block copolymer with the silane. However, when a platinum catalyst is used in the reaction, the tin-based silanol condensation catalyst becomes a catalyst poison, so its use before and during the reaction must be avoided. The high-molecular weight or cross-linked thermoplastic styrene-butadiene block copolymer resin produced by the method of the present invention has excellent tensile strength and rigidity compared to ordinary styrene-butadiene block copolymer resins. It is equivalent to polystyrene homopolymer, its impact resistance is better than polystyrene homopolymer, and its oil resistance is as good as ABS. The silane-added block copolymer composition of the present invention may be mixed with a thermoplastic resin such as low-density polyethylene, high-density polyethylene, polystyrene, vinyl chloride resin, or ABS resin, if necessary.
It is also possible to mix appropriate amounts of various fillers such as silane-modified silica, calcium carbonate, dry silica, wet silica, glass fiber, calcium carbonate, oils, stabilizers, various silicones, and the like. In this case, the condensation reaction may be carried out before, during or after mixing. The composition of the silane-added block copolymer produced by the method of the present invention can be used to produce a wide variety of practically useful products such as sheets, films, foams, adhesives, shoe soles, and injection molded products. Arrived,
It must be said that the present invention has great industrial significance. Hereinafter, some examples will be given to show specific embodiments of the present invention, but these are intended to explain the gist of the present invention more specifically, and are not intended to limit the present invention. Example 1 An autoclave with an internal volume of 10, equipped with a stirrer and a jacket, was dried and replaced with nitrogen. While maintaining this autoclave at 50° C., 267 g of previously purified and dried styrene and 1.067 g of cyclohexane were supplied, and then 0.75 g of a hexane solution of butyllithium was supplied as butyllithium to initiate the polymerization reaction. One hour after the addition of the catalyst, 120 g of butadiene, 266 g of styrene, and 1,466 g of cyclohexane, which had been purified and dried in advance, were added, and the temperature was raised to 70° C. to continue polymerization. After a further 1 hour, 80 g of butadiene, 267 g of styrene and 1,467 g of cyclohexane, which had been purified and dried in advance, were added and polymerized at 70°C for 1 hour. After the polymerization reaction was completed, butylated hydroxytoluene (BHT) was added as a stabilizer to the obtained styrene-butadiene copolymer solution. A portion of the solution was taken out, the copolymer was precipitated using excess methanol, and the precipitate was dried under reduced pressure. (This is referred to as Comparative Sample A.) The styrene content of Comparative Sample A was 80%. In another 10 autoclaves, 2.5Kg of the above styrene-butadiene copolymer solution (copolymer amount
500g), then 8g of methyldiethoxysilane and 0.04g of 2-ethylhexanol-modified chloroplatinic acid solution (5% chloroplatinic acid) were added, and the temperature was 80°C.
The reaction was carried out with stirring at ℃ for 10 hours. After the reaction was completed, an antioxidant was added to the polymer solution and heated under reduced pressure to distill off the solvent and unreacted silane. The amount of silane added was calculated from the quantitative determination of the amount of unreacted silane, and it was found that 1.4 parts by weight was added to 100 parts of the block copolymer. When the infrared absorption spectrum of the obtained silane addition block copolymer was measured, strong absorption based on Si-O-C bonds was observed at 1.075 cm ^-1 and 1.105 cm ^-1 , which was not present in the copolymer before the addition reaction. Admitted. Sample 1 of the present invention was prepared by dry mixing 100 parts by weight of this silane-added block copolymer with 1 part by weight of dibutyltin dilaurate in a Brabender for 20 minutes. Next, using sample 1 of the present invention and comparative sample A,
The melt index was measured (results are shown in Table 1). Melt indexing of Sample 1 of the present invention was performed under a dry nitrogen atmosphere to prevent crosslinking due to moisture. As shown in Table 1, the inventive samples had approximately the same melt index as the comparative samples, indicating that the melt flow properties were not substantially altered by the addition of silane. In addition, a large amount of Sample 1 and Sample A synthesized by the same method were injection molded using an in-line screw type 5-ounce injection molding machine under conditions of a cylinder temperature of 200°C and a mold temperature of 30°C. A 2mm sheet was created. Since Sample 1 has almost the same melt flowability as Comparative Sample A, it is possible to mold it with the same injection pressure.
It was found that it maintains excellent processability as a thermoplastic resin. In addition, sample 1 was used during injection molding.
It was stable without crosslinking in the injection molding machine. For the measurement of the physical properties in Table 1, the sheet was used as is for Comparative Example A, and the sheet was heated at 50°C for 20 minutes for Sample 1.
A sheet was used that was crosslinked by exposure to steam for minutes. For comparison, Stylon 683 (comparative example, sample B), a polystyrene homopolymer, was similarly molded and its physical properties were measured. Table 1 summarizes the physical property measurement results.

【table】

[Table] As is clear from Table 1, sample 1 of the present invention has significantly improved tensile strength and rigidity (maximum bending stress and bending modulus) due to crosslinking, and also has improved hardness and impact resistance. has also improved. Therefore,
Sample 1 of the present invention is far superior to Comparative Sample A without silane in terms of tensile strength, stiffness, and hardness, and is comparable to polystyrene homopolymer, while impact resistance is It is a resin with extremely well-balanced physical properties that are superior to polystyrene homopolymer, and it is also clear that it has excellent oil resistance because it does not dissolve in toluene. Example 2 Injection molded sheet obtained in Example 1 (Sample 1)
After being left at room temperature for 10 days, physical properties were measured and the tensile strength and rigidity were found to be high, and the fact that it was hardly soluble in toluene suggested that it had been crosslinked. Physical properties after standing for 10 days Tensile strength 400Kgf/cm ² Maximum bending stress 800Kgf/cm ² Flexural modulus 2300Kgf/cm ² Rockwell hardness 108 (R scale) Haze value 1.7% Toluene solubility No dissolution Example 3 Internal volume 10 An autoclave with a stirrer was purged internally with nitrogen gas, dehydrated and degassed in advance, 1.
A 30% by weight n-hexane solution containing 224 g of 3-butadiene was charged. Next, 0.14 g of an n-hexane solution of 1,4-dilithio-n-butane was added as an active lithium compound, and polymerization was carried out at 60°C for 1 hour. After the polymerization of the monomer was substantially completed, it was purified and dried. A 30% by weight n-hexane solution containing 96 g of styrene was added and polymerized at 60°C for 1 hour. A hexane solution was obtained. Furthermore, n of the above B-A-B type block copolymer
-Concentration of 1280g of styrene in hexane solution
A 30% by weight n-hexane solution and an n-hexane solution containing 0.72 g of n-butyllithium as an active lithium compound were added, and polymerization was carried out at 60° C. for 2 hours with stirring. Using the obtained polymer solution, a reaction with methyldimethoxysilane was carried out in the same manner as in Example 1. The obtained silane addition block copolymer was
It showed a strong characteristic absorption based on Si-O-C bonds at 1070 cm ^-1 . The amount of silane added estimated from the reaction conversion rate of silane is per 100 parts by weight of the block copolymer.
It was 1.3 parts by weight. Sample 2 of the present invention was prepared by dry mixing 100 parts by weight of this silane-added block copolymer and 1 part by weight of dibutyltin laurate in a Brabender for 20 minutes. The block copolymer before addition of silane is designated as Comparative Example Sample C. Sample 2 and Sample C were compression molded to create a 2 mm thick sheet, and sample 2 was placed in hot water at 50°C for 5 minutes.
The material was crosslinked by immersion for a period of time and its physical properties were measured. The results are shown in Table 2.

【table】

【table】

【table】

Claims (1)

[Claims] 1 General formula (A-B) _n or B(-A-B) _n or A(-B-A) _n or B-A(-A-B) _o (wherein A is A polymer block mainly composed of conjugated diene, B represents a polymer block mainly composed of styrene, the content of conjugated diene in the copolymer is at least 3% by weight and less than 40% by weight, and n is 2 or more, m is an integer of 1 or more) and has a molecular weight of 10,000 to 400,000 and is composed of a styrene polymer block and a conjugated diene polymer block, or a block copolymer of these blocks and polystyrene. 100 parts by weight of a mixture with HR _3-a SiX _a (wherein R is an alkyl group, an allyl group or a vinyl group, and X is selected from an alkoxy group, an acyloxy group, an oxime group, a substituted amino group) represents a hydrolyzable organic group, and a is 2 or 3. A thermoplastic resin composition that can be made to have a high molecular weight or be crosslinked by contact.