Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2000-04-21
2003-07-29
Sellers, Robert E. L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S232000, C525S240000
Reexamination Certificate
active
06599984
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a rubber modifier for improving workability in roll kneading, extrusion and so on by admixing to rubber and, more specifically, to a rubber modifier superior in the effect of modification of workability and in the handling.
DESCRIPTION OF THE RELATED TECHNIQUES
Ethylene/propylene copolymer rubber (EPR) and ethylene/propylene/diene copolymer rubber (EPDM) are superior in the heat resistance and weatherability, as compared with generally used rubbers based on diene, since they do not have unsaturation bond in the main chain, so that they find application in many products including automobile parts, industrial structural materials and parts and so on.
In accordance with the increased requirement for the performance of rubber products in recent years, the molecular weights of EPR and EPDM tend to become increased. However, EPRs and EPDMs having higher molecular weights are inferior in the workability in, for example, roll kneading and extrusion, whereby a problem results in the production efficiency.
A lower molecular weight ethylene/&agr;-olefin copolymer rubber is known to have an ability to improve the above-mentioned workability without deteriorating the material properties of the rubber.
However, such a lower molecular weight ethylene/&agr;-olefin copolymer rubber exhibits too high of a viscosity to handle it as a flowable mass but is too soft to handle it as a solid mass, so that its handling performance is too low to be used widely.
Therefore, it has been expected to find a novel rubber modifier which is superior in the handling performance and which can afford to improve the workability of an ethylene/&agr;-olefin copolymer rubber, such as EPR or EPDM, in roll kneading and in extrusion without deteriorating the material properties intrinsic for such a copolymer rubber by simply admixing thereto.
SUMMARY OF THE INVENTION
An object of the present invention is to obviate the problem incidental to the prior technique mentioned above and to provide a rubber modifier which is easy to handle and which can improve the workability of ethylene/&agr;-olefin copolymer rubber, such as EPR and EPDM, without deteriorating the material properties of the copolymer rubber to be blended with the rubber modifier.
Thus, the present invention is directed to a rubber modifier which comprises an ethylene/&agr;-olefin copolymer rubber (A) composed of one or more copolymers selected from the group consisting of a copolymer of ethylene and an &agr;-olefin having 3-20 carbon atoms and a copolymer of ethylene, an &agr;-olefin having 3-20 carbon atoms and a non-conjugated polyene, wherein the copolymer rubber (A) has the parameters of
an ethylene/&agr;-olefin mole ratio in the range of 51/49 to 87/13,
an intrinsic viscosity [&eegr;] determined in decahydronaphthalene at 135° C. in the range of 0.8 to 2.5 dl/g and
an iodine value in the range of 0 to 40.
A preferred rubber modifier according to the present invention comprises
60-90% by weight of an ethylene/&agr;-olefin copolymer rubber (A1) having the parameters of
an ethylene/&agr;-olefin mole ratio in the range of 50/50 to 85/15,
an intrinsic viscosity [&eegr;] determined in decahydronaphthalene at 135° C. in the range of 0.2 to 0.9 dl/g and
an iodine value in the range of 0 to 40 and
10-40% by weight of an ethylene/&agr;-olefin copolymer rubber (A2) having the parameters of
an ethylene/&agr;-olefin mole ratio in the range of 60/40 to 90/10,
an intrinsic viscosity [&eegr;] determined in decahydronaphthalene at 135° C. in the range of 3 to 6 dl/g and
an iodine value in the range of 0 to 40.
DETAILED DESCRIPTION OF THE INVENTION
<The Ethylene/&agr;-Olefin Copolymer Rubber (A)>
The ethylene/&agr;-olefin copolymer rubber (A) to be used according to the present invention as the rubber modifier is composed of one or more copolymers selected from the group consisting of (1) a copolymer of ethylene and an &agr;-olefin having 3-20 carbon atoms, preferably 3-8 carbon atoms, and (2) a copolymer of ethylene, an &agr;-olefin having 3-20 carbon atoms, preferably 3-8 carbon atoms and a non-conjugated polyene.
For the &agr;-olefin having 3-20 carbon atoms, there may be enumerated concretely, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene. These &agr;-olefins can be used alone or in a combination of two or more of them. Among them, particular preference is given to &agr;-olefins having 3-8 carbon atoms, such as, propylene, 1-butene and 1-octene.
As the non-conjugated polyene, there may be enumerated, for example, cyclic dienes, such as, 5-ethylidene-2-norbornene, 5-propylidene-5-norbornene, di-cyclopentadiene, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-
2
-norbornene and norbornadiene; chain-formed non-conjugated dienes, such as, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-hepta-diene, 6-methyl-1,7-octadiene and 7-methyl-1,6-octa-diene; and trienes, such as, 2,3-diisopropylidene-5-norbornene and 4-ethylidene-8-methyl-1,7-nonadiene. Among them, 1,4-hexadiene, dicyclopentadiene and 5-ethylidene-2-norbornene are preferred.
The ethylene/&agr;-olefin copolymer rubber (A) has an ethylene/&agr;-olefin mole ratio in the range from 51/49 to 87/13, preferably from 55/45 to 80/20, especially preferably from 55/45 to 75/25, an intrinsic viscosity [&eegr;] determined in decahydronaphthalene at 135° C. in the range from 0.8 to 2.5 dl/g, preferably from 1.0 to 2.0 dl/g, especially preferably from 1.2 to 1.8 dl/g, and an iodine value in the range from 0 to 40, preferably from 0 to 20, especially preferably from 0 to 10.
The ethylene/&agr;-olefin copolymer rubber (A) to be used as the rubber modifier according to the present invention may be composed of one single copolymer rubber of ethylene/&agr;-olefin or a composition of two or more copolymer rubbers of ethylene/&agr;-olefin, so long as the three parameters of the ethylene/&agr;-olefin mole ratio, the intrinsic viscosity [&eegr;] and the iodine value thereof are in the above-defined ranges, respectively.
For the ethylene/&agr;-olefin copolymer rubber (A) consisting of a composition of two or more copolymer rubbers of ethylene/&agr;-olefin, it is permissible not only that all the parameters of ethylene/&agr;-olefin mole ratio, intrinsic viscosity [&eegr;] and iodine value of each individual copolymer rubber are in the above-defined ranges, respectively, but also that one or more of these parameters of individual copolymer rubber are outside the above-defined respective range, so long as the three parameters as regards the composition are in the above-defined respective range.
It is permissible to incorporate any voluntary combination of individual ethylene/&agr;-olefin copolymer rubbers for such a composite copolymer rubber (A), so long as the above-mentioned three parameters as regards the composition are in the above-defines ranges, respectively. Concrete examples of such a composite copolymer rubber (A) include the followings:
1) A composition composed of two or more of ethylene/&agr;-olefin copolymer rubbers in which all the three parameters of ethylene/&agr;-olefin mole ratio, intrinsic viscosity [&eegr;] and iodine value of each individual copolymer rubber are in the above-defined ranges, respectively.
2) A composition composed of two or more of ethylene/&agr;-olefin copolymer rubbers in which one or two of the above three parameters are in the above-defined respective range.
3) A composition composed of two or more of ethylene/&agr;-olefin copolymer rubbers in which all the above three parameters are outside the above-defined respective range.
4) A composition composed of one or more of ethylene/&agr;-olefin copolymer rubbers in which all the above three parameters are in the above-defined respective range and of one or more of ethylene/&agr;-olefin copolymer rubbers in which one or two of the above thre
Hakuta Takashi
Kawasaki Masaaki
Koda Taku
Tojo Tetsuo
LandOfFree
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