JP2817240B2 - Thermoplastic elastomer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention relates to a thermoplastic elastomer composition comprising chlorinated polyethylene containing a gel component, polypropylene and a liquid butadiene rubber having an active group. The thermoplastic elastomer composition of the present invention is used in all rubber fields such as rubber electric wires, rubber cables, rubber mats, rubber hoses, rubber roofing and rubber magnets.

(Prior art) Conventionally, a thermoplastic elastomer composition comprising a rubber containing a gel and a polyolefin obtained by dynamically heat-treating and vulcanizing a rubber while kneading the rubber and a polyolefin has a thermal flexibility and rubber elasticity. Because of this, it is molded at a high temperature by utilizing the thermoplastic property of the thermoplastic elastomer, and is used within a temperature range having rubber elasticity. Generally, a thermoplastic elastomer composition has the advantages of being easily flowable at a high temperature and easy to mold, unlike molding of a rubber composition part, and having a short molding time, and requires a vulcanization step in molding of a rubber composition. However, in the case of a thermoplastic elastomer composition, such as not requiring this, because it is superior to the rubber composition in terms of energy consumption or labor costs,
In recent years, it has been widely used in the rubber field.

In recent years, there has been a movement to use chlorinated polyethylene and polypropylene containing gels as thermoplastic elastomers, but thermoplastic elastomer compositions consisting of chlorinated polyethylene and polypropylene containing gels have a static mechanical property of compression Poor in strain and permanent elongation. For example, a rubber mat with inferior compression set starts to deform from the beginning of practical use, changes greatly during practical use, and the useful life of the rubber mat is extremely short. In order to put a thermoplastic elastomer composition comprising a chlorinated polyethylene and a polypropylene containing a gel component into practical use, it is necessary to solve the above problems.

(Problems to be solved by the invention) The present invention has been made as a result of earnest research to solve the above problems,
An object of the present invention is to provide a thermoplastic elastomer composition having solved static mechanical properties.

(Means for Solving the Problems) The present invention resides in a thermoplastic elastomer composition comprising chlorinated polyethylene containing a gel component, polypropylene and liquid butadiene rubber having an active group. The thermoplastic elastomer composition provided by the present invention is extremely excellent in terms of static mechanical properties such as compression set and permanent elongation, and can be put to practical use.

 Hereinafter, the present invention will be described in detail.

The chlorinated polyethylene used in the present invention,
It is obtained by introducing chlorine into polyethylene, ethylene-butene-1 copolymer, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer or the like to form a rubber. The introduction of chlorine into the polymer can be performed by turbidizing the powder or particles of the polymer in water and blowing a chlorine gas or dissolving the polymer in an inert organic agent such as carbon tetrachloride to remove the chlorine gas. Insufflation is performed.

The amount of chlorine is not particularly limited as long as the chlorinated polyethylene is rubbery, but the chlorinated polyethylene having a chlorine amount of 15 to 55% by weight is in a rubbery state.

The chlorinated polyethylene containing the gel component of the present invention,
It refers to chlorinated polyethylene obtained by vulcanizing chlorinated polyethylene by dynamic heat treatment in a kneader. The gel component in the present invention refers to chlorinated polyethylene vulcanized by dynamic heat treatment.
According to JIS K 6388, it is measured with a Harris basket made of 100 mesh stainless steel wire mesh. It refers to the residue of the oil debris in benzene. And the gel content of the chlorinated polyethylene of the present invention is 20% by weight or more, and the gel content is 20% by weight.
If it is less than 1, it is inferior in terms of static mechanical properties such as compression set and permanent elongation, is poor in practical use, and is not preferred. The term "dynamic heat treatment" used herein means vulcanization while flowing chlorinated polyethylene in a kneader to form a gel. The temperature of the dynamic heat treatment is preferably 140 to 250C.

In order to form a gel by this dynamic heat treatment, a metal oxide, a metal lead compound, a metal hydroxide, and a fatty acid metal are used as a dehydrochlorination scavenger and / or a vulcanizing agent for capturing hydrochloric acid generated during vulcanization of chlorinated polyethylene. Soaps such as magnesium oxide, calcium oxide, zinc oxide, lead monoxide, lead trioxide, tribasic lead sulfate, dibasic lead phosphite, calcium hydroxide, sodium stearate, magnesium stearate, calcium stearate, etc. Is blended. These are used alone or as a mixture. Also, thiourea-based compounds, polyamine-based compounds, organic peroxides, thiol derivative compounds, sulfur derivative compounds such as ethylene thiourea, 2-mercaptoimidazole, dicumyl peroxide are used as vulcanizing agents and / or vulcanization accelerators for chlorinated polyethylene. , T-butylcumyl peroxide, 1,3,5
Trithiocyanuric acid, N-cyclohexylbenzyl-2-sulfenamide, N, N'-m-phenylenebismaleimide, 2 mercaptobenzothiazole and the like are blended. These are used alone or as a mixture.
The amounts of the vulcanizing agent and / or the vulcanization accelerator are not particularly limited, and the amount is such that the chlorinated polyethylene is vulcanized by dynamic heat treatment and the gel content becomes 20% by weight or more.

The polypropylene used in the present invention uses a Ziegler-Natta type catalyst and homopolymerizes propylene in an inert solvent, or propylene and an α-olefin such as ethylene, pentene-1, butene-1, 4-ene.
A polymer obtained by copolymerizing methyl pentene-1 and the like, and is crystalline. The polypropylene to be used is not particularly limited in the present invention, but preferably has a melt flow index (MFI) of 0.1 to 30 g / 10 minutes as measured in JIS K7210 (230 ° C., 2.16 kg load). As a commercially available propylene, for example, there is a polypropylene published in Japanese and foreign chemicals A polymer: published by CMC Corporation (1988). These may be used alone or as a mixture. This polypropylene is mixed in an amount of 5 to 50 parts by weight, preferably 10 to 40 parts by weight, per 100 parts by weight of chlorinated polyethylene containing 20% by weight or more of a gel component. If the amount is less than 5 parts by weight, the resulting thermoplastic elastomer composition has poor fluidity and is difficult to mold. Further, when the addition and mixing exceed 50 parts by weight, the obtained molded product is hard, does not show rubber elasticity, and lacks practicality, which is not preferable. The mixing of the polypropylene with the chlorinated polyethylene and the liquid butadiene rubber having an active group is performed at a temperature not lower than the melting point of the polypropylene used.

Of particular importance in the present invention lies in the use of liquid butadiene having active groups. The liquid butadiene rubber having this active group is liquid at room temperature and has a number average molecular weight of 200 to 4000.
A liquid butadiene rubber having an active group such as a hydroxyl group, a carboxyl group, an isocyanate group, an epoxy group, or an amino group at the molecular terminal or in the molecule. These liquid butadiene rubbers having an active group are used alone or as a mixture. The liquid butadiene rubber having an active group exhibits an effect by dynamic heat treatment using a vulcanizing agent. This vulcanizing agent includes a mercapto group, a carboxyl group, and a reactive group, which are reactive with the active group of the liquid butadiene rubber.
A compound having an active group such as a hydroxyl group, an amino group, an epoxy group and an isocyanate group is used. The temperature of the dynamic heat treatment can be performed in a range from normal temperature to 250 ° C. The liquid butadiene rubber having an active group, which constitutes one component of the thermoplastic elastomer composition of the present invention, is used to show compatibility with both chlorinated polyethylene and polypropylene, Compression set and permanent elongation, which are excellent mechanical properties, are remarkably improved. The liquid butadiene rubber having an active group to be added and kneaded is 3 to 20 parts by weight per 100 parts by weight of chlorinated polyethylene. If less than 3 parts by weight, the effect of addition is small and the compression set and permanent elongation of the thermoplastic elastomer are small. Improvement cannot be measured. If the amount exceeds 20 parts by weight, the mechanical strength of the obtained molded product, for example, tensile strength, tear strength and the like is inferior, which is not preferable.

The method for obtaining the thermoplastic elastomer of the present invention uses a roll kneader, a Banbury mixer, a double-arm kneader, a screw-type kneader, a rotor-type continuous kneader, or the like, and chlorinated polyethylene to polypropylene in a molten state at a high temperature. And a method of simultaneously adding and kneading a liquid butadiene rubber having an active group and dynamically heat-treating to obtain a plastic elastomer composition; a chlorinated polyethylene and a liquid butadiene rubber having an active group are subjected to dynamic heat treatment in advance; Method of kneading with polypropylene in (1), a method of kneading chloride butane and liquid butadiene rubber having an active group in advance without dynamic heat treatment, adding this to polypropylene in a molten state at a high temperature, and performing dynamic heat treatment simultaneously with kneading. Or chlorinated polyethylene mixed with polypropylene in the molten state Dynamically heat-treated at the same time, then a method of simultaneously dynamic heat treatment and mixing a liquid butadiene rubber having an active group allyl, a method of obtaining a thermoplastic elastomer of the present invention is not limited thereto. In the thermoplastic elastomer composition of the present invention, a compounding agent for rubber or resin can be added in the process of obtaining the composition or after obtaining the composition. For example, these additives include plasticizers, softeners, anti-aging agents, ultraviolet absorbers, carbon black, or white fillers such as titanium oxide, calcium carbonate, talc and clay, foaming agents, lubricants, slip agents, and antistatic agents. Agents, coloring agents and the like. For the thermoplastic elastomer composition of the present invention, a forming machine such as an extruder, an injection molding machine, a calender roll, a press molding machine, a blow molding machine or a vacuum molding machine is used.

(Examples) The present invention will be described with reference to the following examples, but the present invention is not limited to these examples.

Examples 1 to 4 and Comparative Examples 1 to 4 Table 1 shows the formulations of the thermoplastic elastomer compositions used in Examples and Comparative Examples.

In Example-1, 100 parts by weight of chlorinated polyethylene (Daisolac H-135 manufactured by Daiso Corporation) having the composition shown in Table 1 was used.
Liquid butadiene rubber having an active group (poly bd R-45
5 parts by weight of EPI), 10 parts by weight of calcium hydroxide, 20 parts by weight of DOS, 10 parts by weight of titanium oxide, and 1 part by weight of PM were roll-kneaded at a temperature of 40 ° C. This was added to 20 parts by weight of polypropylene in a molten state at a roll temperature of 180 ° C., and kneaded for 15 minutes, and at the same time, chlorinated polyethylene and liquid butadiene rubber having an active group were subjected to dynamic heat treatment to obtain a thermoplastic elastomer composition. This was preheated for 4 minutes by a compression molding machine at 180 ° C. and press molded for 2 minutes, and then cooled for 4 minutes by a compression cooling machine at 10 ° C. to obtain a sheet having a thickness of 2 mm. The obtained sheet was subjected to a hardness test and a permanent elongation test according to JIS K6301. The elongation in this permanent elongation test was 100% elongation. Table 1 shows the test results. Further, the obtained thermoplastic elastomer composition was preheated by a compression molding machine at 180 ° C. for 6 minutes, pressed and molded for 3 minutes, and then cooled by a compression cooling machine at 10 ° C. for 6 minutes to obtain a 12.7 mm thick film. I got a sheet.
The obtained sheet was subjected to a compression set test at 70 ° C. for 22 hours according to JIS K6301. Table 1 shows the test results.

On the other hand, in order to know the content of the gel of chlorinated polyethylene in the thermoplastic elastomer composition, 100 parts by weight of chlorinated polyethylene (Daisolac H-135 manufactured by Daiso Corporation) having the composition shown in Table 1 was used. 10 parts by weight of calcium and 1 part by weight of PM were roll-kneaded at a temperature of 40 ° C. This was added to 20 parts by weight of polypropylene in a molten state at a roll temperature of 180 ° C., and kneaded for 15 minutes, and at the same time, chlorinated polyethylene was subjected to dynamic heat treatment.

According to JIS K 6388, the residue not extracted into benzene at 23 ° C. was measured with a Harris basket made of a 100-mesh stainless steel wire mesh. The gel content of the chlorinated polyethylene was calculated by the following equation. The calculation results are shown in Table 1.

L0: Weight of sample before benzene extraction L1: Total weight of polypropylene and calcium hydroxide or magnesium oxide added by kneading in sample before benzene extraction L2: Weight of residue unextracted into benzene Except that 5 parts by weight of liquid butadiene rubber having an active group of 1 (poly bd R-45EPI) was changed to 10 parts by weight, a thermoplastic elastomer composition was obtained according to Example 1, and a hardness test, a permanent elongation test and A compression set test was performed. Table 1 shows the test results. A test to determine the content of the chlorinated polyethylene gel in the thermoplastic elastomer composition was not performed because it was the same as in Example-1.

Example 3 is the same as Example 1 except that 5 parts by weight of the liquid butadiene rubber having active groups (poly Rd-45EPI) of Example 1 was changed to 20 parts by weight, and 20 parts by weight of polypropylene was changed to 10 parts by weight. -1, a hardness test, a permanent elongation test and a compression set test were performed. The test for determining the gel content of the chlorinated polyethylene was not performed because it was the same as in Example-1.

Example-4 is a liquid butadiene rubber having an active group poly bd R-45EPI of Example 1 was replaced with poly bd R-45EPT of a liquid butadiene rubber having an active group, except that calcium hydroxide was changed to magnesium oxide. The test was performed according to Example-1.

Comparative Example-1 followed Example-1 except that 1 part by weight of PM in Example-1 was omitted.

Comparative Example-2 was carried out by changing 20 parts by weight of the polypropylene in the molten state at the roll temperature of 180 ° C of Example-1 to 3 parts by weight, but the thermoplastic elastomer composition obtained on the roll at 180 ° C was Due to poor fluidity, it turned into a powder and could not be tested for migration.

In Comparative Example-3, a test was performed in accordance with Example-1, except that 5 parts by weight of the liquid butadiene rubber having an active group (polybd R-45ERI) having the active group of Example-1 was removed. The test for determining the gel content was not performed because it was the same as in Example-1.

Comparative Example-4 is 20 parts by weight of Example-1 polypropylene.
Example 1 was followed except that the amount was changed to 60 parts by weight. A test for determining the gel content was not performed because it was the same as in Example-1.

As can be seen from Table 1, Examples 1 to 4 are significantly smaller in compression set and permanent elongation than Comparative Examples 1 to 4. Also, as can be seen in Comparative Example-4, the thermoplastic elastomer composed of 60 parts by weight of polypropylene has high hardness and does not show rubber elasticity.

(Effects of the Invention) As is clear from the above description, the thermoplastic elastomer composition of the present invention has a problem of the static elastomer composition comprising a chlorinated polyethylene and a polypropylene containing a gel component, which is a problem of the thermoplastic elastomer composition. The points of compression set and elongation, which are mechanical properties, have been solved, and it can be seen that they are practically usable.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08L 23/28 C08L 23/10-23/14 C08L 7/00-21/02

Claims (1)

(57) [Claims] 1-5 parts by weight of polypropylene per 100 parts by weight of chlorinated polyethylene containing at least 20% by weight of a gel component,
A thermoplastic elastomer composition containing 3 to 20 parts by weight of a liquid butadiene rubber having an active group.