JPH01210443A - Chlorosulfonated ethylene/alpha-olefin copolymer composition - Google Patents

Abstract

PURPOSE:To obtain the title copolymer composition improved in heat resistance, low-temperature resistance and water resistance, by mixing a specified chlorosulfonated ethylene/alpha-olefin copolymer with a hydrotalcite, a thiuram, a maleimide and a dithiocarbamate. CONSTITUTION:100 pts.wt. chlorosulfonated ethylene/alpha-olefin copolymer of a chlorine content of 25-32wt.%, a sulfur content of 0.3-2.5wt.% and an ethylene to alpha-olefin ratio of 98/2-60/40 is mixed with 10-35 pts.wt. hydrotalcite, 0.5-5 pts.wt. thiuram (e.g., dipentamethylenethiuram), 0.5-5 pts.wt. maleimide (e.g., N,N'-m-phenylenedimaleimide), and 0.2-4 pts.wt. dithiocarbamate (e.g., nickel dibutyldithiocarbamate).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 that provides a vulcanized product with excellent heat resistance, cold resistance, and water resistance.

The present composition is particularly useful in the field of rubber belts such as toothed rubber belts and polyethylene belts. ' [Prior Art] Chlorosulfonated polymers, represented by chlorosulfonated polyethylene, are members of the same halogenated polymer family and have properties similar to chloroprene rubber.

However, in order to show superior properties compared to chloroprene rubber in terms of heat resistance, weather resistance, and ozone resistance,
It is positioned as a polymer with better heat resistance.

For this reason, attempts are being made to replace chloroprene rubber with chlorosulfonated polymers in fields where the heat resistance of chloroprene rubber is currently at its limit.

For example, rubber belts such as toothed belts and poly V belts are examples.

However, since chlorosulfonated polyethylene has inferior cold resistance compared to chloroprene rubber, it may be difficult to meet the cold resistance required for toothed belts.

Therefore, in Japanese Patent Application No. 61-217935, we proposed a toothed comb belt whose characteristic is to use a chlorosulfonated ethylene/α-olefin copolymer as the rubber material.

On the other hand, in the field of toothed rubber belts, the aforementioned heat resistance,
In addition to cold resistance, improving the water resistance of products is also an important technical issue.

It is known that it is effective to use lead compounds such as litharge and red lead as acid acceptors to improve the heat resistance and water resistance of chlorosulfonated polyethylene vulcanizates. However, considering the environmental pollution caused by the toxicity of lead compounds, this cannot be said to be appropriate.

Against this background, we conducted extensive studies to obtain a product after vulcanization that has better heat resistance, better cold resistance, and better water resistance, and filed Japanese Patent Application No. 62-203059.

However, as we continued to consider it further, we found that
The inventors discovered that heat resistance was significantly improved by further adding a dithiocarbamate to the composition of No. 059, leading to the present invention.

[Problem to be solved by the invention] The purpose of the present invention is to improve the heat resistance of the product after vulcanization,
An object of the present invention is to provide a chlorosulfonated ethylene/α-olefin copolymer composition that has better cold resistance and water resistance.

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

[Means for Solving the Problems] That is, the present invention provides a) a chlorine content of 25 to 32% by weight and a sulfur content of 0.3 to 2.5%.
a) Hydrosarutites 1 per 100 parts by weight of chlorosulfonated ethylene/α-olefin copolymer
Chlorosulfonated ethylene α prepared by blending 0 to 35 parts by weight, 0.5 to 5 parts by weight of thiurams, 0.5 to 5 parts by weight, e) 0.2 to 4 parts by weight, maleimides, and - an olefin copolymer composition.

[Function] In the present invention, in order to obtain a vulcanized product with excellent heat resistance, cold resistance, and water resistance, it is important to use specific substances described in Book 411 of the present invention in a specific combination.

That is, A), B), I), E), and E) must be included in the chlorosulfonated ethylene/α-olefin copolymer composition as essential components in carrying out the present invention.

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

Ethylene/α-olefin copolymers include, for example, ethylene/butene-1 copolymer, ethylene/propylene copolymer, ethylene/hexene-1 copolymer, ethylene/octene-1 copolymer, ethylene/4-methyl -Pentene-
1 copolymer, etc.

The ratio of ethylene to α-olefin is 98/2 to 60/40
It is desirable that

However, the symbols A to B indicate that the number is greater than or equal to A and less than or equal to B.

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

Particularly preferred is a copolymer of ethylene and butene-1 in which the ratio of ethylene to butene-1 is in the range of 9515 to 70/30.

Once the composition of the raw material ethylene/α-olefin is determined, the composition ratio of ethylene/α-olefin in the single chlorosulfonated ethylene/α-olefin copolymer obtained by chlorinating and chlorosulfonating it is maintained as is. .

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

That is, the ratio of ethylene to butene-1 is 98/2 to 60/4.
The number of ethyl groups per 1000 carbon atoms is 10 to 0.
It may be displayed as 200 pieces.

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

If the amount of chlorine is less than 25% by weight or if the amount of chlorine is more than 32% by weight, it is difficult to obtain useful cold resistance.

Particularly preferably 28 to 31% by weight.

The amount of sulfur contained in the chlorosulfonated ethylene/α-olefin copolymer is a measure of the amount of -5O2Cβ groups that act as crosslinking points, and is preferably 0.3 to 2.5% by weight.

Particularly preferred is 0.5 to 1.5% by weight.

The method for synthesizing a chlorosulfonated ethylene/α-olefin copolymer involves using an ethylene/α-olefin copolymer as a raw material, using a radical generator as a catalyst, and using chlorine and sulfur dioxide gas, chlorine and sulfuryl chloride, or sulfuryl chloride alone. The reaction method is a general synthesis method.

The reaction may be carried out in a homogeneous system in which the substance is dissolved in a solution, in a heterogeneous system in which it is suspended in a solution, or in a heterogeneous system in which it is suspended in a gas phase.

f! ! The homogeneous method of dissolving the raw material ethylene/α-olefin copolymer in a solvent is the only method to obtain a chlorosulfonated ethylene/α-olefin copolymer that has excellent heat resistance and cold resistance. in a better way,
desirable.

At this time, the solvent used was carbon tetrachloride and chloroform.

A solvent inert to the halogenation reaction, such as monochlorobenzene or tetrachloroethane, is used.

A) chlorine amount 25 to 32% by weight obtained in this way,
Based on 100 parts by weight of a chlorosulfonated ethylene/α-olefin copolymer with a sulfur content of 0.3 to 2.5% by weight, a) 10 to 35 parts by weight of hydrosartites, and 2) 0.5 to 5 parts by weight of thiurams. The composition of the present invention is constituted by adding as essential components 0.5 to 5 parts by weight of maleimides and 0.2 to 4 parts by weight of dithiocarbamates.

Hydrotalcites include industrially synthesized synthetic hydrotalcite as well as hydrotalcite as a natural mineral produced in the Ural region of the Soviet Union.

For example, D of Kyowa Kagaku Kogyo ■ is used as a synthetic hydrotalcite
HT-4A-2, DHT-4A, KW-2100, KW
-2200 etc.

These hydrotalcites are added as acid acceptors for chlorosulfonated polymers, and in certain combinations shown in the present invention, they exhibit superior heat resistance, cold resistance, and water resistance.

The amount of hydrotalcites added is 10 to 35 parts by weight.

If the amount is less than 10 parts by weight, no effect on water resistance or heat resistance can be expected.

On the other hand, if it exceeds 35 parts by weight, disadvantages such as an increase in the viscosity of the compound and an increase in the hardness of the vulcanizate occur.

More preferably, one containing 13 to 23 parts by weight has a good balance between heat resistance and water resistance, and is also excellent in processability.

Thiurams are generally known as vulcanization accelerators, such as dipentamethylenethiuram tetrasulfide (
TRA), tetramethylthiuram monosulfide (T
S), tetramethylthiuram disulfide (TT or TMTD) and tetraethylthiuram disulfide ('T'' ET).

Thiurams are used in an amount of 0.5 to 5 parts by weight, but if the amount added is small, the vulcanization rate and vulcanization density will not increase, while if the amount added 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, such as N,N'-m-phenylene dimaleimide.

As a commercial product, Parnock PM or HV A-
There are 2.

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

Dithiocarbamates are used in an amount of 0.2 to 4 parts by weight; however, if it is less than 0.2 parts by weight, the effect will not be apparent;
Exceeding parts by weight does not increase the effect.

Preferably it is 0.3 to 3 parts by weight, particularly preferably 0.
．． The amount is 5 to 2 parts by weight.

Examples of dithiocarbamates include nickel dibutyldithiocarbamate (NBC), nickel diethyldithiocarbamate (NEC), zinc dibutyldithiocarbamate, zinc diethyldithiocarbamate, and the like.

Particularly preferred is nickel dibutyldithiocarbamate (
NBC).

Dithiocarbamates are particularly effective in improving heat resistance in certain compositions herein.

That is, the rate of change in elongation of the vulcanizate after being left at high temperatures is small, and the compression set at high temperatures is small.

This is probably because the dithiocarbamates directly act on the vulcanization mechanism of the chlorosulfonated ethylene/α-olefin copolymer in the specific vulcanization system herein.

Although this mechanism is not currently clear, it is important that the above-mentioned object can be achieved in a specific combination according to the present invention.

The composition of the present invention includes a), b), t), d) and e)
In addition to the essential ingredients, reinforcing agents and fillers.

Other conventional rubber compounding agents such as plasticizers, anti-aging agents and processing aids can be added as desired.

Examples of reinforcing agents and fillers include carbon black,
white carbon, calcium carbonate, clay, talc,
Examples include titanium oxide.

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

Anti-aging agents include general amine anti-aging agents and phenolic anti-aging agents.

Processing aids include low molecular weight polyethylene and metal soaps.

As mentioned above, the present invention achieves the above object because it relates to the vulcanization of a chlorosulfonated ethylene/α-olefin copolymer.

For this reason, care must be taken not to use drugs that directly affect vulcanization, such as vulcanizing agents and vulcanization accelerators, in combination with the components of the present composition.

For example, metal oxides or metal hydroxides that act as vulcanizing agents, with the exception of lead compounds, cannot be added in combination.
Should be less than parts by weight.

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

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

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

The resulting compound is breath cured and
The product is vulcanized by steam vulcanization, UHF vulcanization, air heat vulcanization, etc.

[Examples] Next, the present invention will be explained in more detail based on Examples, but these are examples for helping understanding of the present invention, and the present invention is not limited in any way by these Examples.

Note that the values used in these Examples were obtained based on the following measurement method.

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

[Example 1, 2.3. ll and used in Comparative Example 1.2.3] Ethylene-butene-1 copolymer (melt index 4 g/10 min, density 0.89g/cc)3
After dissolving 360 g in carbon tetrachloride, it is reacted with 5620 g of sulfuryl chloride together with 12 g of α,α'-azobisisobutyronitrile as a radical generator and 0.25 g of pyridine as a promoter.

After the reaction was completed, the acid remaining in the solution was removed, and 17 g of 2,2'-bis(4-glycidyloxyphenyl)propane was added as a stabilizer.

The solution was fed to a drum dryer in a conventional manner to separate the product from the solvent.

As a result of analysis, this chlorosulfonated ethylene butene
1 copolymer was found to contain a chlorine content of 30.1% by weight and a sulfur content of 1.02% by weight.

Mooney viscosity (ML, 100°C) is 58 and 1
+4. This is called A-1.

[Examples 1 to 3 and Comparative Examples 1 to 4] After kneading the formulations shown in Table 1 with an open roll, Examples 1 to 3 were 150"CX30 minutes, Comparative Examples 1 to 4 were 15"
Vulcanization was performed at 0°C for 40 minutes to obtain a vulcanized sheet.

Thereafter, the physical properties of the vulcanizate shown in Table 1 were measured.

Note that the Gehman torsion test was used as an index of cold resistance.

Examples 1 to 3 are chlorosulfonated ethylene/α-olefin copolymer compositions having excellent heat resistance, cold resistance, and water resistance according to the present invention.

In particular, the heat resistance is significantly improved by using dithiocarbamates.

In Comparative Example 1, hydrotalcite was not used and magnesia was used as the vulcanizing agent, so the desired water resistance was not obtained.

Furthermore, higher heat resistance has not been achieved.

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

Furthermore, higher heat resistance has not been achieved.

In Comparative Example 3, maleimides and dithiocarbamates were not used, so the heat resistance was poor.

In Comparative Example 4, Hypalon 40, which is a chlorosulfonated polyethylene, is used instead of the chlorosulfonated ethylene/α-olefin copolymer.

For this reason, the desired cold resistance cannot be obtained.

Furthermore, higher heat resistance has not been achieved.

Referring to these Examples and Comparative Examples, it is clear that the present invention provides a chlorosulfonated ethylene/α-olefin copolymer composition that has excellent heat resistance, cold resistance, and water resistance after vulcanization. it is obvious.

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

Therefore, it is particularly useful as a material for comb belts such as toothed belts and polyethylene belts.

On the other hand, it is also applied to fields that require heat resistance, cold resistance, and water resistance, such as sheets, electric wires, and hoses.

Claims (1)

[Claims] 1) A) Chlorine content 25 to 32% by weight, sulfur content 0.3 to 2
．． Based on 100 parts by weight of 5% by weight chlorosulfonated ethylene/α-olefin copolymer, a) 10 to 35 parts by weight of hydrosartites, c) 0.5 to 5 parts by weight of thiurams, and e) 0.5 to 5 parts by weight of maleimides. A chlorosulfonated ethylene/α-olefin copolymer composition containing 5 parts by weight of e) 0.2 to 4 parts by weight of dithiocarbamates.