JP3013466B2 - Thermoplastic elastomer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to thermoplastic elastomer compositions. More specifically, the present invention relates to a thermoplastic elastomer composition comprising chlorosulfonated polyethylene or chlorinated polyethylene, styrene / conjugated diene block copolymer, dehydrochlorination scavenger, softener and / or plasticizer, organic peroxide and polypropylene. . The thermoplastic elastomer composition of the present invention is used in various rubber fields such as rubber electric wires, rubber cables, rubber mats, rubber hoses, rubber roofs and rubber magnets.

[0002]

2. Description of the Related Art Thermoplastic elastomers made from rubber
The molding process of the composition requires a vulcanization step in order to crosslink the rubber, but a thermoplastic elastomer composition containing a gel component in which the rubber and polyolefin are kneaded and subjected to dynamic heat treatment to partially crosslink the rubber. The product has such features that it can be molded in a short time without the need for a vulcanization step, and the molding cost can be reduced. For this reason, in recent years, the demand for a thermoplastic elastomer composition containing a gel component mainly composed of rubber and polyolefin has been increasing.

Along with this, chlorine-containing chlorosulfonated polyethylene or chlorinated polyethylene is superior in physical properties such as oil resistance, ozone resistance, weather resistance and light color to other rubbers. Thermoplastic elastomer compositions containing a gel component mainly composed of chlorosulfonated polyethylene or chlorinated polyethylene and polypropylene which is a polyolefin are also in practical use. However, since this thermoplastic elastomer composition contains a gel component by dynamic heat treatment, its flow characteristics are extremely poor in molding at a high temperature of 100 ° C. or higher. For example, in molding with an injection molding machine, the molding cycle is slow,
In addition, products having complicated shapes cannot be formed, and there are drawbacks in that extrusion speed is low in extrusion molding by an extruder, and products having complicated shapes cannot be formed. Further, the thermoplastic elastomer composition is inferior in mechanical properties such as compression set and tensile strength. For example, rubber mats with inferior compression set will be deformed from the beginning of practical use, and will be greatly deformed during practical use. If the tensile strength is inferior, they will be destroyed by spikes of golf shoes and the like. Becomes extremely short. For this reason, without impairing physical properties such as oil resistance, ozone resistance, weather resistance, lightness of chlorosulfonated polyethylene or chlorinated polyethylene,
There is a strong need to provide a thermoplastic elastomer composition containing a gel component having excellent flow characteristics, compression set and tensile strength.

[0004]

SUMMARY OF THE INVENTION The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have succeeded in reducing the mechanical properties of chlorosulfonated polyethylene or chlorinated polyethylene without impairing the excellent physical properties. The present invention provides a thermoplastic elastomer composition containing a gel component having excellent mechanical properties.

[0005]

The present invention is characterized by chlorosulfonated polyethylene or chlorinated polyethylene, styrene / conjugated diene block copolymer, dehydrochlorination scavenger,
A thermoplastic elastomer composition comprising a softener and / or a plasticizer, an organic peroxide and polypropylene. Hereinafter, the present invention will be described in detail.

The chlorosulfonated polyethylene (hereinafter referred to as CSM) used in the thermoplastic elastomer composition of the present invention.
Means polyethylene, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, etc. Into which rubber and a chlorosulfonyl group are introduced. A method for introducing chlorine and chlorosulfonyl groups is to dissolve the polymer in an inert organic solvent such as carbon tetrachloride,
There is a method of introducing chlorosulfonyl group by injecting chlorine gas and then chlorinating and then adding and reacting chlorosulfonyl, or introducing chlorine and chlorosulfonyl group by chlorosulfonyl. . The amount of chlorine is not particularly limited as long as the CSM is rubbery, but 15 to 55% by weight of the CSM is rubbery. The chlorinated polyethylene (hereinafter referred to as CPE) used in the production method of the present invention refers to a powder or particles of the polymer suspended in water or dissolved in an inert organic solvent such as carbon tetrachloride. Then, chlorine gas is blown and chlorine is introduced to form a rubber. The amount of chlorine is not particularly limited as long as the CPE is rubbery like CSM, but 15 to 55% by weight of CPE is in a rubbery state. that's all,
Although the method for producing CSM and CPE is exemplified, the CSM or CPE used in the thermoplastic elastomer composition of the present invention is not limited to these methods. CSM or CPE for the rubber elastic component used in the present invention
Is used in the range of 60 to 90% by weight. If the amount is less than 60% by weight, oil resistance, which is a physical property of CSM or CPE, is impaired.

The rubber elastic component styrene / conjugated diene block copolymer used in the present invention (hereinafter referred to as SBC)
Is a block copolymer produced by solution polymerization in the presence of a catalyst such as organic lithium and a vinyl aromatic compound and a conjugated diene compound as raw materials, and the content of the vinyl aromatic compound in the block copolymer is 10-55% by weight
It is. Examples of the vinyl aromatic compound include styrene, vinyl toluene, vinyl xylene and α-methylstyrene, and examples of the conjugated diene compound include isoprene and 1,3
-Butadiene, 1,3-pentadiene and the like.
Commercially available SBCs include Enikem Elastomeri
Co., Ltd. Europrene SOL T 161A, 16
1C, 162, 163, 166, 168, 171, 17
2, 174, 176, 177, 190, 192, 193
And the like. S of the rubber elastic component used in the present invention
BC is used in an amount of 5 to 40% by weight. Below 5% by weight, the flow and mechanical properties of the thermoplastic elastomer composition are not improved. If it exceeds 40% by weight, the excellent physical properties of CSM or CPE are impaired, which is not preferred.

The dehydrochloric acid scavenger used in the thermoplastic elastomer composition of the present invention is one which scavenges hydrochloric acid generated when a CSM or CPE is partially crosslinked by dynamic heat treatment. Are metal oxides, metal lead compounds, metal hydroxides, fatty acid metal soaps, such as magnesium oxide, calcium oxide, zinc oxide, lead monoxide, lead tetroxide, tribasic lead sulfate, dibasic lead phosphite , Calcium hydroxide, sodium stearate, magnesium stearate, calcium stearate and the like. These are used alone or as a mixture. The amount used is 0.1 to 30 parts by weight per 100 parts by weight of the rubber elastic component of the present invention.

The softener and / or plasticizer referred to in the present invention is blended to lower the viscosity of the rubber kneaded material to improve the processability of the rubber kneaded material, or to reduce the hardness of the rubber product. The softeners include mineral oil softeners and vegetable oil softeners. Examples include aroma oil, paraffin oil, naphthenic oil, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, coconut oil, and the like. Examples of the plasticizer include phthalic acid esters, dibasic acid esters, glycol esters, epoxy plasticizers, and phosphoric acid esters. For example, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, diheptyl phthalate
, Di-n-octyl phthalate, diisooctyl phthalate, di- (2-ethylhexyl) phthalate, dinonyl phthalate, diisodecyl phthalate, diallyl phthalate, ditridecyl phthalate, Dicyclodecyl phthalate, diisodecyl adipate, di- (2-ethylhexyl) azelate, dibutyl sebacate, di- (2
-Ethylhexyl) isosebakate, diethylene glycol benzoate, triethylene glycol di- (2-
Ethylhexoate), butyl stearate, butyl arylate, methyl acetyl ricinoleate, tetrahydrohalfuryl oleate, butyl epoxy stearate
Octyl epoxy stearate, triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate and the like. These are used alone or as a mixture. The amount used is 5 to 100 parts by weight per 100 parts by weight of the rubber elastic component. If the amount is less than 5 parts by weight, the effect of the thermoplastic elastomer composition of the present invention on the processability is small.

The organic peroxides used in the present invention include hydroperoxides, diacyl peroxides, ketone peroxides, peroxyesters and dialkyl peroxides, for example, t-butyl hydroperoxide. , Cumene hydroperoxide,
Di-isopropylbenzene hydroperoxide,
2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-cumylperoxide, di-t-butylperoxide , N-butyl-4,
4-bis (t-butylperoxy) hexane, t-butylperoxybenzoate, benzoyl peroxide and the like. These are used alone or in combination. The amount of the organic peroxide used is 0.1 to 10 parts by weight per 100 parts by weight of the rubber elastic component used in the present invention. If the amount is less than 0.1 part by weight, mechanical properties such as compression set and tensile strength are inferior. If it is used in excess of 10 parts by weight, the thermoplastic elastomer composition has poor mechanical properties such as fluidity and tensile strength at the time of molding at a high temperature, which is not preferable.

The polypropylene (hereinafter referred to as PP) used in the thermoplastic elastomer composition of the present invention refers to propylene homopolymer or propylene and α-olefin such as ethylene, pentene-1, butene-1,4 −
It is a polymer obtained by copolymerization with methyl pentene-1 and the like, and is crystalline. Examples of commercially available PP include, for example, materials for domestic and foreign chemicals A Polymer: CMC Corporation (198
There is a PP listed in 8). These may be used alone or as a mixture. The amount used is 5 to 50 parts by weight per 100 parts by weight of the rubber elastic component used in the present invention. If the amount is less than 5 parts by weight, the fluidity of the obtained thermoplastic elastomer composition during molding at high temperatures is poor.
If it exceeds 50 parts by weight, it does not exhibit elasticity, which is not preferable.

The method for obtaining the thermoplastic elastomer composition of the present invention is not particularly limited, but a kneader generally used for kneading rubber or resin, such as a roll kneader, a Banbury mixer, Use a double arm kneader, screw type kneader, rotor type continuous kneader, etc.
Alternatively, a method in which CPE, SBC, a dehydrochlorination scavenger, a softener, and / or a plasticizer and PP are kneaded in advance at a temperature equal to or higher than the melting point of PP, and then an organic peroxide is added to perform dynamic heat treatment

The dynamic heat treatment referred to in the present invention means that CSM or CPE and SBC are partially cross-linked with an organic peroxide while not flowing in an organic solvent such as benzene, acetone and cyclohexane while flowing in the kneader. It is to make a gel. Although the gel content is not particularly limited, CSM or C in the thermoplastic elastomer composition is used.
The gel content of PE and SBC is preferably 20% by weight or more. If the amount is less than 20% by weight, the mechanical properties of the thermoplastic elastomer composition are inferior and are not preferred.

[0014] The thermoplastic elastomer composition of the present invention may be added to the thermoplastic elastomer composition during the manufacturing process or to the obtained thermoplastic elastomer composition, for example, a compounding agent for rubber or a resin, such as a radical inhibitor or an antioxidant. A UV absorber, a compatibilizer, a co-crosslinking agent, carbon black, a white filler, a foaming agent, a lubricant, an antistatic agent, a colorant, and the like can be used as necessary.

[0015]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Table 1 shows the formulations used in the examples and comparative examples.

Examples-1 to 4 and Comparative Examples-1 to 3 In the composition-1 shown in Table 1, an organic peroxide, P
P, the rubber elastic component excluding the stabilizer, and the compounding agents were kneaded with a roll kneader at 50 ° C. to obtain a rubber kneaded product. Next, this rubber kneaded material and PP are put into a chamber at a set temperature of 140 ° C. using a Brabender-Plastic-Da Roller-Mixer type, and the rubber kneaded material is mixed with a roller mixer at 100 RPM. Using the heat generated, the temperature of the rubber kneaded material was set to the melting point of PP or more, and PP was melted and dispersed in the rubber kneaded material. Next, a dynamic heat treatment was performed by adding an organic peroxide, and then a stabilizer was added and kneaded to obtain a thermoplastic elastomer composition.

In order to know the fluidity of the obtained thermoplastic elastomer composition, a load of 2 was applied according to JIS K 7210 using a melt indexer manufactured by Toyo Seiki Seisaku-sho, Ltd.
1.6 kg, MFR which is an index of fluidity at a temperature of 190 ° C.
(Melt flow rate) was measured. Further, the obtained thermoplastic elastomer composition was preheated by a compression molding machine at 180 ° C. for 4 minutes and press molded for 2 minutes, and then cooled by a compression cooling machine at 10 ° C. for 4 minutes to form a 2 mm thick shell. A tensile strength was measured from the sheet according to JIS K6301. Further, the obtained thermoplastic elastomer composition was preheated by a compression molding machine at 180 ° C. for 6 minutes and press molded for 3 minutes, and then cooled by a compression cooling machine at 10 ° C. for 6 minutes to obtain a thickness of 12. A 7 mm sheet was obtained. From the obtained sheet, a compression set test was performed under the test conditions of 70 ° C. and 22 hours according to JIS K6301.

Furthermore, CSM or CPE and SB produced by dynamic heat treatment in a thermoplastic elastomer composition
In order to know the amount of the gel composed of C, the amount of the gel was measured according to the following method. The 2 mm sheet obtained by molding the thermoplastic elastomer composition is cut into 1-2 mm squares, 0.5 g of the sheet is put in 100 g of benzene, left at 23 ° C. for 24 hours, and then After stirring for 1 hour with Lumil,
The mixture was allowed to stand for 1 hour to settle the insoluble portion of the thermoplastic elastomer, 5 g of the portion dissolved in benzene was taken out, and the benzene was evaporated. Generated CS
The amount of the gel composed of M or CPE and SBC was calculated by the following equation. GL = {0.5− (L + P)} / 0.5 × 100 where GL: gel content (% by weight) L: weight of the thermoplastic elastomer composition dissolved in 100 g of benzene P: sample 0.5 Polypropylene weight.

The measured MFR, tensile strength, compression set and gel content are shown in Table 1. From Table 1, it can be seen that Examples 1 to 10 obtained by using the thermoplastic elastomer composition of the present invention.
It can be seen that the thermoplastic elastomer composition of No. 4 is superior to Comparative Examples 1 to 3 in all of MFR as an index of flow characteristics and mechanical properties such as tensile strength and compression set.

[0020]

[Table 1]

[0021]

As is apparent from the above description, the thermoplastic elastomer composition of the present invention comprising CSM or CPE, SBC, dehydrochloride scavenger, softener and / or plasticizer, organic peroxide and polypropylene. It can be seen that the sample has excellent flow characteristics and excellent tensile strength and compression set.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 23/28 C08L 23/28 // (C08L 23/28 53:02 23:10) (C08L 23/34 53:02 23: Ten)

Claims (1)

(57) [Claims] 1. A dehydrochlorination scavenger of 0.1 to 100 parts by weight of a rubber elastic component comprising 60 to 90% by weight of chlorosulfonated polyethylene or chlorinated polyethylene and 10 to 40% by weight of a styrene / conjugated diene block copolymer. A thermoplastic elastomer composition comprising 30 parts by weight, 5 to 100 parts by weight of a softening agent and / or plasticizer, 0.1 to 10 parts by weight of an organic peroxide, and 5 to 50 parts by weight of polypropylene.