JPH0333189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic elastic composition, particularly a ternary or quaternary copolymer comprising a block copolymer of a conjugated diene compound and a vinyl-substituted aromatic compound, ethylene and vinyl acetate, and an alkyl acrylate and/or an alkoxyalkyl acrylate. The present invention relates to a thermoplastic elastomer composition suitable for shoe soles having properties such as oil resistance and ozone resistance. Traditionally, there have been various materials used for shoe soles, but natural rubber and styrene-butadiene rubber are expensive because they require vulcanization, and polyurethane resin is unvulcanized. Available, but expensive. On the other hand, soft vinyl chloride resin does not have sufficient thermal stability, low-temperature properties, and slip resistance, and styrene-butadiene copolymer resin is an excellent resin without these drawbacks, but has poor oil resistance and ozone resistance. There is a problem. The present invention has solved these drawbacks, and is a ternary or quaternary copolymer consisting of a block copolymer of a conjugated diene compound and a vinyl-substituted aromatic compound, ethylene and vinyl acetate, and an alkyl acrylate and/or an alkoxyalkyl acrylate. The object of the present invention is to provide a thermoplastic elastomer composition containing the above-mentioned polymers, which retains oil resistance, ozone resistance, and rubber properties. That is, the thermoplastic elastomer composition of the present invention is a direct combination of a conjugated diene compound containing 20 to 70% by weight of a vinyl substituted aromatic compound having a polymerization average molecular weight of 3 x 10 ⁴ to 30 x 10 ⁴ . A ternary or quaternary copolymer (hereinafter referred to as acrylic copolymer) consisting of 100 parts by weight of a block copolymer having a chain structure (hereinafter referred to as block copolymer), ethylene, vinyl acetate, and alkyl acrylate and/or alkoxyalkyl acrylate (hereinafter referred to as acrylic copolymer) ) in an amount of 3 to 100 parts by weight. In the present invention, the block copolymer refers to A(-B
-A) _o-1 , (A-B) _o , (A-B) _ox linear structures. In these formulas, A represents a vinyl-substituted aromatic compound block, B represents a conjugated diene compound block, and X represents a polyfunctional compound in which n polymer chains are bonded, and n is an integer of 2 to 4. .
Note that the connection between the A block and the B block may be a clear cut or a tapered shape. The conjugated diene compounds of these block copolymers include 1,3-butadiene, 1,3-pentadiene,
Examples of vinyl-substituted aromatic compounds include 1,3-hexadiene and isoprene, and examples of vinyl-substituted aromatic compounds include styrene, α-methylstyrene, and vinyltoluene. It is sufficient that the block copolymer in the elastomer composition of the present invention is one in the rubber range, but in particular, vinyl-substituted aromatic compounds are contained in the block copolymer.
Preferably it contains 20 to 70% by weight. 70% by weight
If it exceeds 20% by weight, the permanent elongation will be high and the rubber properties will be significantly impaired, and if it is less than 20% by weight, the rubber hardness will be insufficient. The polymerization average molecular weight is preferably 3 x 10 ⁴ to 30 x 10 ⁴ , and if it is less than 3 x 10 ⁴ , the strength characteristics and abrasion resistance of the resin composition after immersion in oil will be low, and if it exceeds 30 x 10 ⁴ The workability of these materials is extremely poor. On the other hand, acrylic copolymers contain ethylene from 5 to 20
15 to 55 parts by weight of vinyl acetate and alkyl acrylate represented by the following formula () and/or
Alternatively, a ternary or quaternary copolymer comprising 25 to 80 parts by weight of an alkoxyalkyl acrylate represented by the following formula () is preferred. () CH ₂ = CHCOO-R ₁ (R ₁ is an alkyl group having 3 to 8 carbon atoms) () CH ₂ = CHCOO-R ₂ -O-R ₃ (R ₂ is an alkylene group having 1 to 4 carbon atoms, R ₍₃ is an alkyl group or an alkoxyalkyl group having 1 to 4 carbon atoms) The elastomer composition of the present invention is a block copolymer.
However, if the acrylic copolymer is less than 3 parts by weight, the oil resistance and ozone resistance will not improve. Moreover, if the amount exceeds 100 parts by weight, the elongation, fluidity and hardness of the elastic body composition will be significantly reduced, making it undesirable as a rubber elastic body. Furthermore, the elastomer composition of the present invention may contain, in addition to the block copolymer and acrylic copolymer described above, styrene polymer, ethylene polymer, ethylene vinyl acetate copolymer, paraffinic, naphthenic or aromatic process oil. , fillers such as calcium carbonate, clay, silica, and talc, titanium dioxide,
Combining colorants such as carbon, metal stabilizers, stabilizers such as stearic acid, lubricants, vulcanizing agents, etc. has the effect of adjusting hardness, improving moldability, and increasing heat distortion temperature, depending on the application. It is preferable to mix an appropriate amount. To produce the elastomer composition of the present invention, the block copolymer and acrylic copolymer may be blended in predetermined amounts and mixed using a mixer such as a mixing roll, Banbury mixer, kneader, or extruder. In addition, the mixing temperature is 100 to 230℃.
It is preferable to operate under the following conditions. As explained above, the elastomer composition of the present invention is characterized by containing a block copolymer and an acrylic copolymer, and is generally manufactured by injection molding, such as cloth shoes and work shoes that require oil resistance. , used in the soles of athletic shoes and other shoes that require abrasion resistance. It can also be used in other applications that require oil resistance and rubber-like physical properties, such as automobile bumper protectors. The present invention will be explained in detail below with reference to Examples, but the present invention is not limited thereto. Examples 1 to 8 Comparative Examples 1 to 3 100 parts by weight of a styrene-butadiene block copolymer with a polymerization average molecular weight of 15×10 ⁴ , single taper ABA type (A and B are as described above, and the same applies hereinafter) containing 60% by weight of butadiene. and acrylic copolymers <A> and <B> produced by the method below in the amounts shown in Table 1, and 4-methyl-2, 4-methyl-2, as anti-aging agent.
Adding 0.5% by weight each of 6-ditertiary-ethylphenol and trinolylphosphite;
The mixture was kneaded using a 6-inch test roll at a temperature of 160°C. Next, this kneaded material was press-molded at a temperature of 150°C to prepare a test piece, and the test piece was punched out to be used as a measurement sample and various physical properties were measured. The results are shown in Table 1. As shown in Table 1, styrene-butadiene block copolymer and plain rubber have excellent tensile strength and hardness, but are significantly inferior in oil resistance. On the other hand, when 3 parts by weight, 35 parts by weight, 75 parts by weight, and 100 parts by weight of acrylic copolymer <A> were added, the oil swelling degree decreased to 28, 18, 10, and 8.3%, respectively, and oil resistance was improved. It can be seen that other rubber-like physical properties are also maintained. Furthermore, when the amount of the acrylic copolymer <A> exceeds 100 parts by weight (125 parts by weight), oil resistance is greatly improved, but rubber-like physical properties such as tensile strength, elongation, hardness, and fluidity are significantly reduced, resulting in thermoplasticity. It cannot be used as an elastic body composition. Moreover, acrylic copolymer <B
Although the oil resistance of Examples 5 to 8 and Comparative Example 3 using acrylic copolymer <A> is slightly inferior to that of Examples 1 to 4 and Comparative Example 2 using acrylic copolymer <A>, other physical properties are similar to those of acrylic copolymer <A>. It can be seen that there is almost no difference from <A>. Production method of acrylic copolymer Production of acrylic copolymer <A> (ternary system) Polyvinyl alcohol in 40 autoclaves
Dissolve 530g and 21.6g of sodium acetate to make 16.2Kg
An aqueous solution adjusted to have the following properties was added, and while stirring, 2.16 kg of vinyl acetate and 8.64 kg of 2-methoxyethyl acrylate were added and emulsified. After purging the inside of the autoclave with nitrogen gas, ethylene monomer was pressurized from the top. Ethylene pressure is 55 at polymerization temperature of 63℃.
Adjusted to be Kg/cm ² . After that, a 1% aqueous solution of ammonium persulfate was added in several portions,
Polymerization was stopped in about 10 hours. Then demonomer,
The copolymer was coagulated with a 3% aqueous solution of borax and dehydrated, followed by roll drying to obtain a copolymer. The yield of the copolymer was 1.4Kg, and the composition of the obtained copolymer was vinyl acetate 18
parts by weight, 76 parts by weight of 2-methoxyethyl acrylate, and 6 parts by weight of ethylene. Production of acrylic copolymer <B> (quaternary system) Polyvinyl alcohol in 40 autoclaves
530g, sodium acetate 21.6g, Rongarit
Add 32.4g of vinyl acetate, 1.08g of ethylenediaminetetraacetic acid, and 0.54g of ferrous sulfate to a total weight of 16.2kg.
After adding Kg and emulsifying the autoclave, the space inside the autoclave was completely replaced with nitrogen gas, and then ethylene monomer was pressurized from the top. Ethylene pressure is polymerization temperature
The weight was adjusted to 50Kg/cm ² at 55°C. after that,
A mixture of 25 kg of n-butyl acrylate and 2.5 kg of 2-methoxyethyl acrylate and a 1% aqueous solution of ammonium persulfate were added dropwise from separate injection ports over a period of 80 to 10 hours to advance polymerization. After the polymerization is completed, the monomer is removed, and a 3% aqueous borax solution is added to solidify the polymer emulsion.
Dehydrated and dried on a test roll at 120-130°C. The composition of the obtained copolymer was 51 parts by weight of vinyl acetate, 19 parts by weight of n-butyl acrylate, 23 parts by weight of 2-methoxyethyl acrylate, and 7 parts by weight of ethylene.

【table】

[Table] Examples 9 to 12 Comparative Example 4 100 parts by weight of a styrene-butadiene block copolymer with a polymerization average molecular weight of 15×10 ⁴ and a single taper ABA type containing 60% by weight of butadiene and a naphthenic process oil (manufactured by Idemitsu Kosan Co., Ltd., 25 parts by weight of the product name NS-100), the amount of the acrylic copolymer <A> used in Examples 1 to 4 shown in Table 2, and 4-methyl 2,6-dita as an antiaging agent. - sheabutylphenol and polynolylphosphite, respectively.
0.5% by weight was added and kneaded for 15 minutes using a kneader (model D3-5 pressurized kneader manufactured by Moriyama Seisakusho) at a temperature of 180°C, and then formed into a sheet using a 6-inch Teto roll at 160°C. Next, the sheet was press-molded at a temperature of 150°C for 10 minutes to prepare a test piece. Furthermore, the test piece was punched out and used as a measurement sample to measure various physical properties. The results are shown in Table 2. As shown in Table 2, the results of experiments using a ternary system of styrene-butadiene block copolymer, process oil, and acrylic copolymer <A> show that 10 to 100 parts by weight of acrylic copolymer <A> It can be seen that within this range, it has a function as a thermoplastic elastomer composition and its oil resistance is significantly improved.

[Table] The physical properties of Examples and Comparative Examples were measured in the following manner. 1 Oil swelling degree: 50mm x 50mm x 2mm at 5℃ for 72 hours using No. 3 test oil specified in JIS-K-6301.
The test piece was immersed, and the weight change rate (%) before and after immersion was determined. 2 Tensile strength JIS-K-6301 3 Elongation JIS-K-6301 4 Permanent elongation JIS-K-6301 5 Hardness JIS-K-6301 6 Melt flow index JIS-K-6870

Claims (1)

[Claims] 1 100 weight block copolymer having a linear structure of a conjugated diene compound and a vinyl substituted aromatic compound containing 20 to 70% by weight of a vinyl substituted aromatic compound having a polymerization average molecular weight of 3 × 10 ⁴ to 30 × 10 ⁴ and 3 to 100 parts by weight of a ternary or quaternary copolymer of ethylene, vinyl acetate, and alkyl acrylate and/or alkoxyalkyl acrylate.