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
2002-02-06
2004-04-20
Wilson, D. R. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S232000, C525S194000
Reexamination Certificate
active
06723794
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to olefin thermoplastic elastomers, and more particularly to olefin thermoplastic elastomer compositions capable of providing molded products having excellent tensile strength, elongation at break and elastomeric properties.
BACKGROUND OF THE INVENTION
Olefin thermoplastic elastomers have been widely used as elastomers of energy conservation type or resource conservation type, particularly as substituents for vulcanized rubbers, in the fields of, for example, automobile parts, industrial machine parts, electric or electronic parts and building materials.
The olefin thermoplastic elastomers can be divided into those in the crosslinked form and those in the non-crosslinked form. The non-crosslinked thermoplastic elastomers show small variability of quality and are available at low production cost because they need no crosslinking reaction in the preparation thereof. However, the crosslinked olefin thermoplastic elastomers are superior to the non-crosslinked thermoplastic elastomers in various properties such as tensile strength, elongation at break, elastomeric properties (e.g., elongation set, permanent compression set) and heat resistance. This is well known as described in detail in “Rubber Chemistry and Technology”, vol. 53 (1980), p. 141, by A. Y. Coran et al.
The non-crosslinked or partially crosslinked olefin thermoplastic elastomers are described in, for example, Japanese Patent Publications No. 21021/1978, No. 18448/1980, No. 15741/1981, No. 15742/1981, No. 46138/1983, No. 56575/1983, No. 30376/1984 and No. 59139/1987.
As described above, the olefin thermoplastic elastomers include the non-crosslinked thermoplastic elastomers and the crosslinked thermoplastic elastomers, and the non-crosslinked thermoplastic elastomers are inferior to the conventionally known crosslinked thermoplastic elastomers in the tensile strength, elongation at break, elastomeric properties (e.g., elongation set, permanent compression set), heat resistance and low-temperature properties of the molded products thereof, while the crosslinked thermoplastic elastomers are inferior to the conventionally known vulcanized rubbers in the low-temperature properties, tensile strength, elongation at break and elastomeric properties of the molded products thereof. Further, both the non-crosslinked and crosslinked thermoplastic elastomers are superior to the conventionally known vulcanized rubbers such as those of natural rubber, EPDM, SBR, NBR and CR in the processability and cost but inferior in the tensile properties such as tensile strength and elongation at break.
Accordingly, now desired are development of non-crosslinked thermoplastic elastomer compositions capable of providing molded products having more excellent tensile strength, elongation at break, elastomeric properties (e.g., elongation set, permanent compression set), heat resistance and low-temperature properties than the conventionally known non-crosslinked thermoplastic elastomers and development of crosslinked thermoplastic elastomer compositions capable of providing molded products having more excellent low-temperature properties, tensile strength, elongation at break and elastomeric properties than the conventionally known vulcanized rubbers.
Also desired is development of olefin thermoplastic elastomer compositions capable of providing molded products having more excellent tensile properties such as tensile strength and elongation at break than the conventionally known vulcanized rubbers.
OBJECT OF THE INVENTION
It is, therefore, an object of the present invention to provide an olefin thermoplastic elastomer composition which can provide molded products of excellent tensile strength, elongation at break, elastomeric properties, heat resistance and low-temperature properties even when it is in the non-crosslinked form, and which can provide molded products of more excellent low-temperature properties, tensile strength, elongation at break and elastomeric properties than the conventionally known vulcanized rubbers when it is in the crosslinked form.
It is another object of the invention to provide a partially or completely crosslinked olefin thermoplastic elastomer composition capable of providing molded products having such excellent properties as mentioned above.
It is a further object of the invention to provide a partially or completely crosslinked olefin thermoplastic elastomer composition capable of providing molded products having more excellent tensile properties such as tensile strength and elongation at break than the conventionally known vulcanized rubbers.
SUMMARY OF THE INVENTION
The olefin thermoplastic elastomer composition of the invention is a thermoplastic elastomer composition comprising a crystalline polyolefin resin (A) in an amount of not less than 10 parts by weight and less than 60 parts by weight and an ethylene/&agr;-olefin
onconjugated polyene copolymer rubber (B) which comprises ethylene, an &agr;-olefin of 3 to 20 carbon atoms and a nonconjugated polyene in an amount of not more than 90 parts by weight and more than 40 parts by weight, the total amount of said components (A) and (B) being 100 parts by weight,
wherein the ethylene/&agr;-olefin
onconjugated polyene copolymer rubber (B) is obtained by random copolymerizing ethylene, an &agr;-olefin of 3 to 20 carbon atoms and a nonconjugated polyene in the presence of a metallocene catalyst and has the following properties:
(1) said copolymer rubber contains (a) units derived from ethylene and (b) units derived from the (&agr;-olefin of 3 to 20 carbon atoms in a molar ratio of 40/60 to 95/5 ((a)/(b));
(2) the iodine value is in the range of 1 to 50; and
(3) the intrinsic viscosity (&eegr;), as measured in decalin at 135° C., is in the range of 0.1 dl/g to 10 dl/g.
Preferred embodiments of this thermoplastic elastomer composition are the following compositions (1) and (2).
The olefin thermoplastic elastomer composition (1) is a thermoplastic elastomer composition comprising a crystalline polyolefin resin (A) in an amount of not less than 10 parts by weight and less than 60 parts by weight and an ethylene/&agr;-olefin
onconjugated polyene copolymer rubber (B) which comprises ethylene, an &agr;-olefin of 3 to 20 carbon atoms and a nonconjugated polyene in an amount of not more than 90 parts by weight and more than 40 parts by weight, the total amount of said components (A) and (B) being 100 parts by weight,
wherein the ethylene/&agr;-olefin
onconjugated polyene copolymer rubber (B) is obtained by random copolymerizing ethylene, an &agr;-olefin of 3 to 20 carbon atoms and a nonconjugated polyene in the presence of a metallocene catalyst and has the following properties:
(1) said copolymer rubber contains (a) units derived from ethylene and (b) units derived from the &agr;-olefin of 3 to 20 carbon atoms in a molar ratio of 40/60 to 95/5 ((a)/(b));
(2) the iodine value is in the range of 1 to 50;
(3) the intrinsic viscosity (&eegr;), as measured in decalin at 135° C., is in the range of 0.1 dl/g to 10 dl/g, and
(4) the ratio g&eegr;* of the intrinsic viscosity (&eegr;) of said copolymer rubber (B) determined in the property (3) to the intrinsic viscosity (&eegr;)
blank
of a linear ethylene-propylene copolymer having the same weight-average molecular weight (measured by a light scattering method) as the copolymer rubber (B) and having an ethylene content of 70% by mol, (&eegr;)/(&eegr;)
blank
, is more than 0.95.
The ethylene/&agr;-olefin
onconjugated polyene copolymer rubber (B) for constituting the thermoplastic elastomer composition (1) preferably further has, in addition to the above properties (1) to (4), the following properties:
(5) the intensity ratio D of T&agr;&bgr; to T&agr;&agr; in the
13
C-NMR spectrum, T&agr;&bgr;/T&agr;&agr;, is not more than 0.5;
(6) the B value, as determined by the
13
C-NMR spectrum and the following equation, is in the range of 1.00 to 1.50,
B
value=(
P
OE
)/(2·(
P
E
)·(
P
O
))
wherein (P
E
) is a molar fraction of the units derived from ethylene (a) in the copolymer
Itoh Yuichi
Kawasaki Masaaki
Kobayashi Kyoko
Okada Keiji
Sagane Toshihiro
Burns Doane , Swecker, Mathis LLP
Mitsui Chemicals Inc.
Wilson D. R.
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