JPH0819306B2 - Chlorosulfonated ethylene / α-olefin copolymer composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a chlorosulfonated ethylene / α-olefin copolymer composition.

More specifically, the present invention relates to a chlorosulfonated ethylene / α-olefin copolymer composition having excellent heat resistance, cold resistance and water resistance after vulcanization.

The composition is particularly useful in the field of rubber belts such as toothed rubber belts and poly V belts.

[Related Art] A chlorosulfonated polymer represented by chlorosulfonated polyethylene has similar properties to chloroprene rubber as a member of the same halogenated polymer.

However, since it shows more excellent properties than chloroprene rubber in terms of heat resistance, weather resistance and ozone resistance, it is positioned as a polymer having more excellent heat resistance.

Therefore, attempts have been made to replace the chloroprene rubber with a chlorophosphonated polymer in a field where the heat resistance of the chloroprene rubber has reached its limit.

For example, it is a rubber belt typified by a toothed belt and a poly V belt.

However, since chlorosulfonated polyethylene is inferior in cold resistance to chloroprene rubber, it may be difficult to clear the cold resistance required for a toothed belt.

Therefore, in Japanese Patent Application No. 61-217935, we proposed a toothed rubber belt characterized by using a chlorosulfonated ethylene / α-olefin copolymer as a rubber material.

On the other hand, in the field of toothed rubber belts, it is also an important technical subject to improve the water resistance of products in addition to the above-mentioned heat resistance and cold resistance.

It is known that it is effective to use lead compounds such as litharge and red lead as an acid acceptor in order to improve the heat resistance and water resistance of chlorophosphonated polyethylene vulcanizates. However, it is not appropriate considering environmental pollution due to the harmfulness of lead compounds.

From such a background, the inventors have made earnest studies so that the vulcanized product has better heat resistance, better cold resistance, and better water resistance, and have accomplished the present invention. .

[Problems to be Solved by the Invention] The object of the present invention is to provide a chlorosulfonated ethylene / α-olefin copolymer composition having excellent heat resistance, cold resistance and water resistance of the vulcanized product. Is to provide.

The composition according to the present invention is particularly effective as a composition for a rubber belt such as a toothed rubber belt and a poly V belt.

[Means for Solving Problems] That is, the present invention is: a) Chlorosulfonated ethylene / α-olefin copolymer 10 having a chlorine content of 25 to 32% by weight and a sulfur content of 0.3 to 2.5% by weight.
Chlorosulfonated ethylene / α-olefin copolymer prepared by blending a) hydrotalcites 10 to 35 parts by weight c) thiurams 0.5 to 5 parts by weight d) maleimides 0.5 to 5 parts by weight with respect to 0 parts by weight It is a composition.

[Action] In the present invention, in order to obtain a vulcanized product excellent in heat resistance, cold resistance and water resistance, it is important to use a specific product described in this specification in a specific combination.

That is, a), a), c) and d) are essential components for forming the present invention.
It must be included in the α-olefin copolymer composition.

Chlorosulfonated ethylene / α-olefin copolymer is a generic term for products obtained by chlorinating and chlorophosphonating an ethylene / α-olefin copolymer as a raw material.

Examples of the ethylene / α-olefin copolymer include ethylene / butene-1 copolymer, ethylene / propylene copolymer and ethylene / hexene-1 copolymer. Examples thereof include ethylene / octene-1 copolymer and ethylene / 4-methyl-pentene-1 copolymer.

The ratio of ethylene to α-olefin is preferably 98/2 to 60/40.

However, the symbols A to B indicate that the number is A or more and B or less.

If the ratio of the two is out of this range, it becomes difficult to obtain the desired cold resistance.

Particularly preferably, it is a copolymer of ethylene and butene-1 and the ratio of ethylene to butene-1 falls within the range of 95/5 to 70/30.

Once the composition of the raw material ethylene / α-olefin is determined,
The composition ratio of ethylene / α-olefin of the chlorosulfonated ethylene / α-olefin copolymer obtained by chlorination and chlorosulfonation is maintained as it is.

On the other hand, the molar ratio of ethylene and butene-1 may also be expressed as the number of ethyl groups per 1000 carbon atoms.

That is, when the ratio of ethylene to butene-1 is 98/2 to 60/40, the number of ethylene groups per 1000 carbon atoms may be indicated as 10 to 200.

The amount of chlorine contained in the chlorosulfonated ethylene / α-olefin copolymer is 25 to 32% by weight.

If the chlorine content is less than 25% by weight or the chlorine content exceeds 32% by weight, it is difficult to obtain useful cold resistance.

 Particularly preferably, it is 28 to 31% by weight.

The amount of sulfur contained in the chlorosulfonated ethylene / α-olefin copolymer is a measure of the amount of —SO ₂ Cl groups that act as crosslinking points, and is preferably 0.3 to 2.5% by weight.

 Particularly preferably, it is 0.5 to 1.5% by weight.

A method of synthesizing a chlorosulfonated ethylene / α-olefin copolymer is to use ethylene / α-olefin copolymer as a raw material and a radical generator as a catalyst, chlorine and sulfurous acid gas, chlorine and sulfuryl chloride or chlorine sulfuryl alone. The method of reacting is a general synthetic method.

The reaction may be carried out in a homogeneous system dissolved in a solution, in a heterogeneous system suspended in a solution, or in a heterogeneous system suspended in a gas phase.

However, as a method for obtaining a chlorosulfonated ethylene / α-olefin copolymer excellent in both heat resistance and cold resistance, a homogeneous system obtained by dissolving a raw material ethylene / α-olefin copolymer in a solvent is used. Better and desirable.

At this time, as the solvent, a solvent inert to the halogenation reaction such as carbon tetrachloride, chloroform, monochlorobenzene, and tetrachloroethane is used.

A) thus obtained chlorosulfonated ethylene / α having a chlorine content of 25 to 32% by weight and a sulfur content of 0.3 to 2.5% by weight.
-A) 10 to 35 parts by weight of hydrotalcites, u) 0.5 to 5 parts by weight of thiurams, and e) 0.5 to 5 parts by weight of maleimides are added as essential components to 100 parts by weight of an olefin copolymer. The composition of the invention is made up.

The hydrotalcites include not only hydrotalcite as a natural mineral produced in the Ural region of the Soviet Union, but also synthetic hydrotalcite synthesized industrially.

Examples of synthetic hydrtalcite include DHT-4A-2, DHT-4A, KW-2100, and KW-2200 manufactured by Kyowa Chemical Industry Co., Ltd.

These hydrotalcites are added as an acid acceptor of a chlorosulfonated polymer, but show superior heat resistance, cold resistance, and water resistance only in a specific combination shown in the present invention. .

The addition number of hydrotalcites is 10 to 35 parts by weight.

If the amount is less than 10 parts by weight, the effect on water resistance and heat resistance cannot be expected.

On the other hand, when the amount exceeds 35 parts by weight, there are large defects such as an increase in viscosity of the compound and an increase in hardness of the vulcanized product.

More preferably, the amount of 13 to 23 parts by weight has a good balance between heat resistance and water resistance and is excellent in workability.

Thiurams are generally known as vulcanization accelerators,
For example, dipentamethylenethiuram tetrasulfide (TRA), tetramethylthiuram monosulfide (T
S), tetramethylthiuram disulfide (TT or TMT
D) and tetraethylthiuram disulfide (TET)
There is.

The amount of thiuram used is 0.5 to 5 parts by weight, but if the amount of addition is small, the vulcanization speed and vulcanization density will not increase, while if the amount of addition is large, the water resistance will decrease.

 Therefore, it is more preferably 1 to 3 parts by weight.

Maleimides are known as vulcanization accelerators or anti-aging agents, for example N, N'-m-phenylenedimaleimide.

Commercial products include Barnock PM and HVA-2.

Maleimides are used in an amount of 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight for the purpose of further improving heat resistance.

The above-mentioned hydrotalcites, thiurams, and maleimides interact with each other to vulcanize the chlorosulfonated ethylene / α-olefin copolymer.

It is not clear at this time how this mechanism works, but it is important that in certain combinations according to the present invention the aforementioned objectives can be achieved.

In addition to the essential components of a), b), c) and d), the composition of the present invention contains other conventional rubber compounds such as reinforcing agents, fillers, plasticizers, antioxidants and processing aids. Agents can be added as needed.

Examples of the reinforcing agent and the filler include carbon black, white carbon, calcium carbonate, clay, talc, and titanium oxide.

Examples of plasticizers include various oils, esters and chlorinated paraffins.

Anti-aging agents include nickel dibutyldithiocarbamate (NBC), amine-based antioxidants, and phenol-based antioxidants.

Processing aids include low molecular weight polyethylene, metal soap and the like.

As described above, the present invention relates to the vulcanization of a chlorosulfonated ethylene / α-olefin copolymer, and thus achieves the above object.

Therefore, it is necessary to be cautious to use agents such as a vulcanizing agent and a vulcanization accelerator, which directly affect vulcanization, as the components of the present composition.

For example, metal oxides or metal hydroxides acting as vulcanizing agents, except for lead compounds, should be added less than 3 parts by weight.

For example, the combined use of magnesia, calcium oxide, and calcium hydroxide deteriorates the water resistance of the present invention.

Further, the combined use of a sulfur-based vulcanization accelerator also deteriorates the water resistance, so that the combined use should be less than 3 parts by weight.

The composition according to the present invention is added and compounded by a closed kneader such as a Banbury mixer or an intermix or a usual rubber kneading machine such as an open roll.

The resulting compound is vulcanized by press vulcanization, steam vulcanization, UHF vulcanization, air thermal vulcanization, etc., like ordinary rubber products, to give a product.

[Examples] Next, the present invention will be described in more detail based on examples, but these are examples for helping to understand the present invention, and the present invention is not limited by these examples.

The values used in these examples are obtained according to the following measuring methods.

Molar ratio of ethylene and butene-1: ¹³ C-NMR analysis Melt index: JIS K 7210 Density: JIS K 7112 Chlorine and sulfur content: Combustion flask method Mooney viscosity: JIS K 6300 Vulcanized rubber Physical properties: JIS K 6301 The chlorosulfonated ethylene / butene-1 copolymer used in this example was synthesized as follows.

[Used in Examples 1, 2, 3, 4 and Comparative Examples 1, 2, 3] Ethylene 91.7 mol%. Butene-1 3360 g of ethylene-butene-copolymer (melt index 4 g / 10 min, density 0.89 g / cc) having a composition of 8.3 mol% was dissolved in carbon tetrachloride, and α, α'as a radical generator was dissolved. -React with 5620 g of sulfuryl chloride together with 12 g of azobisisobutyronitrile and 0.25 g of pyridine as cocatalyst.

After the completion of the reaction, the acid content remaining in the liquid was removed, and 17 g of 2,2'-bis (4-glycidyloxyphenyl) propane as a stabilizer was added. The solution was fed to the drum dryer by a conventional method to separate the product from the solvent.

As a result of the analysis, it was found that the chlorosulfonated ethylene / butene-1 copolymer contained 30.1% by weight of chlorine and 1.02% by weight of sulfur. Mooney viscosity (ML _{1 + 4} , 100
℃) was 58. This is called A-1.

[Used in Example 5] A product was obtained according to the method used in Example 1 except that the ethylene / butene-1 copolymer as a raw material was changed as follows.

 Ethylene to butene-1 ratio: 92.3 / 7.7 Melt index: 3g / 10min Density: 0.89g / cc.

As a result of the analysis, this chlorosulfonated ethylene butene
One copolymer was found to contain a chlorine content of 30.0% by weight and a sulfur content of 0.99% by weight.

 The Mooney viscosity was 65. This is called A-2.

[Used in Example 6] A product was obtained according to the method used in Example 1 except that the ethylene / butene-1 copolymer as a raw material was changed as follows.

Ethylene to butene-1 ratio: 92.3 / 7.7 Melt index: 8g / 10min Density: 0.89g / cc.

As a result of analysis, this chlorosulfonated ethylene butene-1
The copolymer was found to contain 30.0% by weight chlorine and 1.01% by weight sulfur.

The Mooney viscosity (ML _{1 + 4} , 100 ° C) was 44. This is called A-3.

[Examples 1 to 6 and Comparative Examples 1 to 4] After kneading the ingredients shown in Table 1 with an open roll,
It was vulcanized at 150 ° C for 40 minutes to obtain a vulcanized sheet.

 Then, the physical properties of the vulcanizates shown in Table 1 were measured.

As an indicator of cold resistance, a Gehman torsion test was used.

Examples 1 to 6 are chlorosulfonated ethylene / α-olefin copolymer compositions excellent in heat resistance, cold resistance and water resistance according to the present invention.

In Comparative Example 1, the desired water resistance was not obtained because magnesia was used as a vulcanizing agent without using hydrotalcite.

In Comparative Example 2, the amount of hydrotalcite was small, and desired water resistance was not obtained.

In Comparative Example 3, since maleimides are not used,
Poor heat resistance.

In Comparative Example 4, chlorosulfonated polyethylene, Hypalon 40, was used instead of the chlorosulfonated ethylene / α-olefin copolymer. Therefore, desired cold resistance has not been obtained.

With reference to these Examples and Comparative Examples, the present invention provides a chlorosulfonated ethylene / α-olefin copolymer composition having excellent heat resistance, cold resistance and water resistance after vulcanization. Is clear.

[Effects of the Invention] Chlorosulfonated ethylene / α obtained by the present invention
-The olefin copolymer composition has a heat resistance of the product after vulcanization,
It has the characteristics of excellent cold resistance and water resistance.

Therefore, it is particularly useful as a material for rubber belts such as toothed belts and poly V belts.

On the other hand, it is also applied to other fields in which heat resistance, cold resistance and water resistance are required, such as sheets, electric wires and hoses.

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Claims (1)

[Claims] 1. A) Chlorine amount 25 to 32% by weight, sulfur amount 0.3 to
A) Hydrotalcites 10 to 35 parts by weight c) Thiuram 0.5 to 5 parts by weight d) Maleimides 0.5 to 5 parts by weight to 2.5 parts by weight of 100 parts by weight of chlorosulfonated ethylene / α-olefin copolymer. A chlorosulfonated ethylene / α-olefin copolymer composition blended.