JPH0730281B2 - Rubber composition for coating - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rubber composition for coating, and particularly, a coating which is extremely effective as a coating material for a rubber product which has extremely high weather resistance and is required to have long-term durability. The present invention relates to a rubber composition.

[Prior Art] Rubber products used for various building materials, machine parts, etc. are generally required to have long-term durability. For such a rubber product, weather resistance under its use condition is a very important factor for determining durability.

By the way, general-purpose rubbers such as natural rubber (NR), butadiene rubber (BR), and styrene-butadiene rubber (SBR), which are widely used as ordinary rubber product materials, exhibit excellent properties under static and dynamic conditions. However, the weather resistance such as ozone resistance, ultraviolet resistance, heat aging resistance, oxidation deterioration resistance, and radiation resistance is poor. For this reason, these rubbers themselves are not suitable for products that require long-term use, and when manufacturing products that can withstand long-term use using the above rubber materials, the outer surface of the rubber product is usually weather-resistant. A method of coating with another rubber material having excellent properties is adopted.

Among such rubber materials for coating, ethylene-propylene rubber is ozone resistance, radiation resistance, oxidation deterioration resistance,
It is known to be extremely excellent in ultraviolet resistance, heat aging resistance, low temperature characteristics and the like.

[Problems to be Solved by the Invention] However, this ethylene-propylene rubber has poor adhesion with the above-mentioned general-purpose rubber, poor adhesion with metal, poor tackiness, poor workability, elongation at break, etc. It has drawbacks such as poor fracture characteristics, and its use as a coated rubber is limited.

[Means and Actions for Solving Problems] The coating rubber composition of the present invention comprises a cyclopentadiene resin and / or a dicyclopentadiene resin in an amount of 10 to 40 in 100 parts by weight of a rubber containing ethylene-propylene rubber as a main component. 5 to 20 parts by weight of the rosin derivative are blended.

In the rubber composition for coating of the present invention, a cyclopentadiene resin and / or a dicyclopentadiene resin,
In addition, a rosin derivative is blended, and the adhesiveness with various rubbers and metals, tackiness, processability, and breaking properties are remarkably improved, and the ethylene-propylene rubber also has high weather resistance.

The present inventors have solved the above-mentioned conventional problems, and have earnestly studied to obtain a coating rubber composition in which the above-mentioned disadvantages are improved without impairing the excellent weather resistance of ethylene-propylene rubber. It has been found that the cyclopentadiene resin or the dicyclopentadiene resin improves the processability of rubber and causes a chemical reaction or physical interaction with the rubber during vulcanization to contribute to the improvement of rubber physical properties.

Specifically, the cyclopentadiene resin or the dicyclopentadiene resin has better workability in compounding with rubber and generates less heat than ordinary process oils.

 Decrease in fracture characteristics due to blending is small.

A rubber containing ethylene-propylene rubber as a main component and these resins blended therein has good adhesiveness to various rubbers and metals. In addition, it was confirmed that the migration of ordinary process oil during long-term use was hardly observed, and the rubber properties were excellent in long-term stability.

The present invention will be described in detail below.

In the present invention, a cyclopentadiene resin or a dicyclopentadiene resin to be blended with a rubber containing ethylene-propylene rubber as a main component is a petroleum resin mainly containing cyclopentadiene or dicyclopentadiene, and is cyclopentadiene or dicyclopentadiene. And a copolymer of an olefinic hydrocarbon which is copolymerizable therewith, or a polymer of cyclopentadiene and / or dicyclopentadiene. Incidentally, these resins are required to have 30 wt% or more, preferably 50 wt% or more of the resin weight in terms of the weight of cyclopentadiene, dicyclopentadiene or a mixture of cyclopentadiene and dicyclopentadiene. To be done.

In addition, as cyclopentadiene or an orphanes hydrocarbon copolymerizable with dicyclopentadiene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl- Olefinic hydrocarbons such as 1-butene and 2-methyl-2-butene; butadiene, isoprene, 3-methylbutadiene 1,
And disubstituted hydrocarbons such as styrene, α-methylstyrene, vinyltoluene, etc., such as cyclopentadiene or dicyclopentadiene and Friedel hydrocarbon in the presence of a suitable catalyst. Kraft can be copolymerized by reaction or the like.

In the present invention, such a cyclopentadiene resin or a dicyclopentadiene resin has a softening point (ring and ball) in consideration of its molecular weight and reactivity of double bond in order to be effective in terms of physical properties of the vulcanized rubber. Formula JIS K-5902) is 50-2
The bromine number (ASTM D-1158-57T) at 00 ° C is preferably in the range of 40 to 150. More preferable softening point is 80 to 150
C., and more preferable bromine number is 50 to 150.

In the present invention, the blending amount of these cyclopentadiene resin and / or dicyclopentadiene resin is 10 to 40 parts by weight, preferably 15 to 35 parts by weight, relative to 100 parts by weight of a rubber containing ethylene-propylene rubber as a main component. Is.

On the other hand, the main component of the rosin derivative is abietic acid,
It is a mixture of pimaric acid and a carboxylic acid having a structure similar to these, and various rosin-based esters, polymerized rosins, hydrogenated rosins, cured rosins, hyrosins, zinc resinates, modified rosins and the like can be mentioned.

The blending amount of such a rosin derivative is 5 to 20 parts with respect to 100 parts by weight of a rubber containing ethylene-propylene rubber as a main component.
Parts by weight.

The ethylene-propylene rubber that is the rubber component of the coating rubber composition of the present invention includes ethylene-propylene diene rubber (EPDM) containing a diene as the third component, and ethylene-propylene rubber containing no third component ( EPR) and oil-extended ethylene-propylene diene rubber, oil-extended EPR.

General-purpose rubbers such as NR, BR, and SBR may be added to these ethylene-propylene rubbers, if necessary, for the purpose of improving processability and the like. In this case, the amount of general-purpose rubber added is 70 parts by weight or less, preferably 60 parts by weight or less, based on 100 parts by weight of ethylene-propylene rubber.

Various vulcanization accelerators can be used in such a rubber composition for coating of the present invention depending on its application. As the vulcanization accelerator, thiazole-based, guanidine-based, thiuram-based, dithiocarbamate-based and the like are preferable, and particularly N-cyclohexyl-2-benzothiazole sulfenamide, dibenzothiazyl disulfide, tetramethylthiuram monosulfide, 2 -Mercaptobenzothiazole, 2-mercaptobenzothiazole cyclohexylamine salt, tetra-2-ethylhexyl thiuram disulfide, di-2-ethylhexyl dithiocarbamic acid zinc salt, and diphenylguanidine are preferable, and N is particularly preferable.
Optimal are cyclohexyl-2-benzothiazole sulfenamide and diphenylguanidine. The addition amount of the vulcanization accelerator is preferably in the range of 0.5 to 5 parts by weight.

Furthermore, the coating rubber composition of the present invention may contain various compounding agents that are generally used in rubber materials, such as various fillers, antioxidants, plasticizers, softeners, and oils.

Such a coating rubber composition of the present invention has extremely excellent weather resistance and is extremely effective as a coating material for various rubber products that are used dynamically or statically for a long period of time. Therefore, the rubber composition for coating of the present invention is a seismic isolation rubber, fender, anti-vibration rubber, belt, hose, tire tube, electric wire, bumper, O-ring, roll, rubber for bridge, leisure boat,
It can be applied to products such as air mats, webs, and gaskets. Of these, seismic isolation rubber, fenders,
Effective for rubber for bridges. The coating rubber composition of the present invention is extremely effective as a coating material for seismic isolation rubber.

[Examples] The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Examples 1 to 3 and Comparative Examples 1 and 2 Rubber compositions having the compositions shown in Table 1 were produced, and the physical properties thereof were examined. The results are shown in Table 1 below. Note that all physical property values were measured at 25 ° C.

From Table 1, it can be seen that the rubber compositions of Comparative Examples 1 and 2 have small elongation at break, low adhesiveness to the iron plate, and extremely low adhesive strength to natural rubber, while dicyclopentadiene resin and hyrozine are used. The coating rubber compositions of the present invention of Examples 1 to 3 in which the composition has a large elongation at break or breaking strength, and excellent adhesiveness with a natural rubber composition and adhesiveness with a metal It is clear.

Examples 4 to 6 and Comparative Example 3 The weather resistance of the rubber compositions of Examples 1 to 3 was examined, and a normal natural rubber composition (100 parts by weight of natural rubber, 20 parts by weight of HAF carbon, 10 parts by weight of spindle oil) was used. , 1.5 parts by weight of sulfur, and 1 part by weight of antiaging agent) were evaluated in comparison with the weather resistance.
The results are shown in Table 2.

From Table 2, the coating rubber composition of the present invention shows extremely high values not only in ozone resistance but also in elongation at break after heat deterioration, retention rate of break strength and flex resistance after heat deterioration. It is clear that it has excellent heat deterioration performance.

[Effects of the Invention] As described in detail above, the rubber composition for coating of the present invention has excellent weather resistance such as ozone resistance, radiation resistance, oxidative deterioration resistance, ultraviolet resistance, heat aging resistance, and low temperature characteristics. Excellent and has good durability for a long period of time in all static and dynamic environments. Moreover, the coating rubber composition of the present invention has good adhesiveness to other rubbers, metals, etc., is excellent in tackiness and workability, and is remarkably excellent in mechanical properties such as elongation at break.

Therefore, the rubber composition for coating of the present invention can be used as a coating material for various rubber products with good adhesiveness and processability, and can protect the rubber products for a long period of time reliably and effectively. . The coating rubber composition of the present invention is extremely effective particularly as a coating material for seismic isolation rubber.

Claims (1)

[Claims] 1. A rubber composition comprising ethylene-propylene rubber as a main component and 100 parts by weight of a cyclopentadiene resin and / or dicyclopentadiene resin and 5 to 20 parts by weight of a rosin derivative. A rubber composition for coating, which is characterized.