Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-12-19
2002-12-10
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S148000, C526S159000, C526S172000, C526S348000, C526S348100, C526S348600, C525S240000, C525S101000, C525S191000, C525S242000, C525S277000, C525S326100, C428S036800, C428S516000, C428S500000, C428S523000, C428S511000, C428S513000, C174S11000P, C174S1100SR
Reexamination Certificate
active
06492475
ABSTRACT:
DESCRIPTION
1. Technical Field
The present invention relates to an ethylene-&agr;-olefin copolymer which possesses various superior properties and a superior processability; a composition of the same; a film and a polar group-containing resin material of the same; and products and uses of the same. More concretely, the present invention relates to an ethylene-&agr;-olefin copolymer suitable for various packaging films manufacturing by means of T-die technique, inflation techniques, and the like, molded films such as a film for lamination, blow-molded products such as various containers manufactured by means of blow molding, injection-molded products such as various vessels, lids, containers, and the like, manufactured by means of injection molding, covering for electric wires, cables, steel pipes, and the like; a composition thereof; and a film and a polar group-containing resin material thereof. The present application is based on Japanese Patent Application No. Hei 10-173594, Japanese Patent Application No. Hei 10-197879, Japanese Patent Application No. Hei 10-197880, Japanese Patent Application No. Hei 10-226229, and Japanese Patent Application No. Hei 10-226231, the contents of which are incorporated herein by reference.
2. Background Art
The conventional, linear low density polyethylene (LLDPE) having a density of 0.89 to 0.94 g/cm
3
comprises an ethylene-&agr;-olefin copolymer produced by means of using a Ziegler catalyst. This conventional LLDPE is superior in strength and toughness to a high pressure process low density polyethylene (HpLDPE) obtained according to a high pressure radical polymerization, and applied to various uses such as films, sheets, blow-molded products, injection-molded products, and the like.
However, the conventional LLDPE possesses a distinct disadvantage in that it is inferior with respect to its processability. Therefore, in the field of films such as packaging materials, improvements in the gap width of the die in a processing device, as disclosed in U.S. Pat. No. 4,243,619 (Union Carbide Chemicals and Plastics Technology Corporation, hereinafter referred to as UCC), in addition to blending of the aforementioned HpLDPE into a LLDPE, have been developed.
More recently, it has become highly desirable to improve the both the overall strength and the sealing strength (i.e., low temperature heat sealability) of an LLDPE, in order to increase the speed of the processing cycle, by means of high-speed filling, and also reduce the weight of the molded products.
In recent years, an ethylene-&agr;-olefin copolymer which exhibits an improved low temperature heat sealability and strength has been developed. This ethylene-&agr;-olefin copolymer is obtained by means of using a metallocene catalyst, the molecular weight distribution and composition distribution of which are extremely narrow, which serves to impart high strength. Such an ethylene-&agr;-olefin copolymer is disclosed in, for example, Japanese Patent Application, First Publication Laid Open No. Sho 60-35009 (WPI: 85-001577, U.S. Pat. No. 4,540,753/Exxon Chemical Patents Inc., hereinafter referred to as Exxon), Japanese Patent Application, First Publication No. Hei 3-502710 (WPI: 90-132257, U.S. Pat. No. 5,382,630/Exxon), Japanese Patent Application First Publication No. Hei 7-500131 (WPI: 90-134412, U.S. Pat. No. 5,250,612/The Dow Chemical Company, hereinafter referred to as Dow), Japanese Patent Application, First Publication No. Hei 7-500622 (WPI: 93-152427, U.S. Pat. No. 5,272,236, WO930822/Dow), Japanese Patent Application, First Publication Laid Open No. Hei 8-311260 (WPI: 96-507707, U.S. Pat. No. 5,798,427/UCC), Japanese Patent Application, First Publication Laid Open No. Hei 9-255724 (WPI: 96-435560, EP735060/UCC), Japanese Patent Application, First Publication No. Hei 8-505174 (U.S. Pat. No. 5,420,220/Mobil Oil Corporation, hereinafter referred to as Mobil), Japanese Patent Application, First Publication No. Hei 9-511003 (WPI: 95-351300, EP751967, WO95/26372/Mobil), and the like.
However, these conventional, ethylene-&agr;-olefin copolymers obtained by means of using a metallocene catalyst, (mLLDPE), possesses several disadvantages. For example, since their composition distribution and molecular weight distribution are extremely narrow, and their properties of viscosity and strength change dramatically according to the temperature, these copolymers pose the problems of having only a limited applicable range for the temperature, extrusion conditions, and the like during the processing process, in addition to an inferior processability. In addition, the aforementioned mLLDPE is inferior both with respect to its properties of thermal resistance, even after being processed to a molded product, and with respect to its heat sealability, due to the narrow range of temperatures which can impart the appropriate heat sealing strength.
Japanese Patent Application, First Publication No. Hei 6-509528, (WO93/03093/Exxon) discloses a heat-sealed product wherein the heat sealing initiation temperature is less than 93° C., by means of using a polymer which possesses a narrow composition distribution of at least 50 on the composition distribution breadth index (CDBI). However, this heat-sealed product possesses improved properties of a low temperature heat sealability, but exhibits an inferior thermal resistance, and an inferior heat-sealing strength.
A blended composition of mLLDPE obtained by means of using a metallocene catalyst and HpLDPE, and film thereof are disclosed, for example, in Japanese Patent Application, First Publication No. Hei 9-511273, (WO95/27005/Mobil), Japanese Patent Application, First Publication Laid Open No. Hei 6-65442, (WPI: 93-407455, U.S. Pat. No. 5,594,071/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-65443, (WPI: 93-407455, U.S. Pat. No. 5,674,945/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application First Publication Laid Open No. Hei 6-136194, (WPI: 94-197254/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 6-136196, (WPI: 94-197255/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication laid Open No. Hei 9-183816, (EP781789A2, WPI: 97-334856/Mitsui Petrochemicals Ind., Ltd.), Japanese Patent Application, First Publication Laid Open No. Hei 9-59440, (WPI: 97-248282/Toso Corporation), Japanese Patent Application, First Publication No. Hei 8-502532, (WPI: 94-151264, U.S. Pat. No. 5,562,958/Dow), and the like. Composition and films disclosed therein are superior in their processability, however, possess disadvantages such as having a narrow applicable range for the temperature at which an adequate heat sealing strength is exhibited, due to their narrow molecular weight distribution and composition distribution.
An ethylene-60-olefin copolymer, which improves on the aforementioned problems, is disclosed in Japanese Patent Application, First Publication No. Hei 8-325333, (WPI: 96-435559, U.S. Pat. No. 5,874,513/Nippon Petrochemicals Co., Ltd., a joint venture partner of the applicant of the present invention). This ethylene-&agr;-olefin copolymer is superior in low temperature heat sealability, hot tacking properties, and the like, but also displays an insufficient thermal resistance, processability, and the like.
In general, the thermal resistance of a polyethylene resin can be improved by means of increasing its density and the amount of components possessing high melting points. However, since the amount of components having a low melting point simultaneously decreases, the heat sealing initiation temperature also rises, and a deterioration in the clarity and reduction in flexibility, due to an increased elasticity, unavoidably result.
In order to solve the aforementioned problem, Japanese Patent Application, First Publication No. Hei 8-501812, (WPI: 94-118420, U.S. Pat. No. 5,376,439/Exxon), and Japanese Patent Application, First Publication No. Hei 9-505094, (WPI: 95-194055, U.S. Pat. No. 5,530,065/Exxon), disclose a method for mi
Asada Fumio
Egashira Toshiaki
Higuchi Reiji
Hiraki Kenichi
Ikeda Masaaki
Japan Polyolefins Co., Ltd.
Rabago R.
LandOfFree
Ethylene/&agr;-olefin copolymer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ethylene/&agr;-olefin copolymer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ethylene/&agr;-olefin copolymer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2925360