Ethylene/pentene-1 copolymer, and ethylene/pentene-1 copolymer composition

An ethylene/pentene-1 copolymer obtained by copolymerizing at least ethylene and pentene-1 in the presence of an olefin polymerization catalyst formed from a titanium catalyst component in a liquid form comprising a halogen-containing magnesium compound, oleyl alcohol and a titanium compound, and a halogen-containing organoaluminum compound under such conditions that not less than 80 % by weight of the resulting ethylene/pentene-1 copolymer is dissolved in a reaction solvent or melted;

• said ethylene/pentene-1 copolymer fulfilling the following requisites (A) to (E):
• (A) a melt flow rate of said copolymer as measured according to ASTM D 1238E is in the range of 0.01 to 100 g/10 min;
• (B) a density of said copolymer as measured according to ASTM D 1505 is in the range of 0.87 to 0.94 g/cm.sup.3 ;
• (C) said copolymer contains constitution units derived from pentene-1 in an amount of 1 to 25 % by weight;
• (D) in the case that said copolymer is subjected to cast molding to prepare a film having a thickness of 40 .mu.m, a ratio (RS) of impact strength of the film to tearing strength of the film in the take-off direction of the film satisfies the following formula:
• RS.gtoreq.-20 log MFR-1000d+968
• wherein MFR represents a melt flow rate of said copolymer, and d represents a density of said copolymer;
• and
• (E) in the case that said copolymer is melted at 200.degree. C., then slowly cooled to 50.degree. C. at a cooling rate of 0.31.degree. C./min and crystallized to prepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peak pattern of the sample obtained when the sample is heated from 10.degree. to 200.degree. C. at a heating rate of 10.degree. C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of a height of the peak (Hh) on the higher temperature side to a height of the peak (Hl) on the lower temperature side and the density of said copolymer satisfy the following formula:
• <
• Hh/Hl<60d-52.0
• wherein Hh represents a peak height on the higher temperature side, Hl represents a peak height on the lower temperature side, and d represents a density of said copolymer.

An ethylene/pentene-1 copolymer composition comprising an ethylene/pentene-1 copolymer (I) and at least one compound (II) selected from the group consisting of a phenolic stabilizer (a), an organic phosphite stabilizer (b), a thioether stabilizer (c), a hindered amine stabilizer (d) and a metal salt of a higher aliphatic acid (e);

• said ethylene/pentene-1 copolymer (I) being obtained by copolymerization of ethylene and pentene-1 and fulfilling the following requisites (A) to (E):
• (A) a melt flow rate of said copolymer as measured according to ASTM D 1238E is in the range of 0.01 to 100 g/10 min;
• (B) a density of said copolymer as measured according to ASTM D 1505 is in the range of 0.87 to 0.94 g/cm.sup.3 ;
• (C) said copolymer contains constitution units derived from pentene-1 in an amount of 1 to 25 % by weight;
• (D) in the case that said copolymer is subjected to cast molding to prepare a film having a thickness of 40 .mu.m, a ratio (RS) of impact strength of the film to tearing strength of the film in the take-off direction of the film satisfies the following formula:
• RS.gtoreq.-20 log MFR-1000d+968
• wherein MFR represents a melt flow rate of said copolymer, and d represents a density of said copolymer;
• and
• (E) in the case that said copolymer is melted at 200.degree. C., then slowly cooled to 50.degree. C. at a cooling rate of 0.31.degree. C./min and crystallized to prepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peak pattern of the sample obtained when the sample is heated from 10.degree. to 200.degree. C. at a heating rate of 10.degree. C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of a height of the peak (Hh) on the higher temperature side to a height of the peak (Hl) on the lower temperature side and the density of said copolymer satisfy the following formula:
• <
• Hh/Hl<60d-52.0
• wherein Hh represents a peak height on the higher temperature side, Hl represents a peak height on the lower temperature side, and d represents a density of said copolymer.

An ethylene/pentene-1 copolymer composition comprising an ethylene/pentene-1 copolymer (I') and at least one compound (II) selected from the group consisting of a phenolic stabilizer (a), an organic phosphite stabilizer (b), a thioether stabilizer (c), a hindered amine stabilizer (d) and a metal salt of a higher aliphatic acid (e);

• said ethylene/pentene-1 copolymer being obtained by copolymerizing at least ethylene and pentene-1 in the presence of an olefin polymerization catalyst formed from a titanium catalyst component in a liquid form comprising a halogen-containing magnesium compound, oleyl alcohol and a titanium compound, and halogen-containing organoaluminum compound under such conditions that not less than 80 % by weight of the resulting ethylene/pentene-1 copolymer is dissolved in a reaction solvent or melted, and fulfilling the following requisites (A) to (E):
• (A) a melt flow rate of said copolymer as measured according to ASTM D 1238E is in the range of 0.01 to 100 g/10 min;
• (B) a density of said copolymer as measured according to ASTM D 1505 is in the range of 0.87 to 0.94 g/cm.sup.3 ;
• (C) said copolymer contains constitution units derived from pentene-1 in an amount of 1 to 25 % by weight;
• (D) in the case that said copolymer is subjected to cast molding to prepare a film having a thickness of 40 .mu.m, a ratio (RS) of impact strength of the film to tearing strength of the film in the take-off direction of the film satisfies the following formula:
• RS.gtoreq.-20 log MFR-1000d+968
• wherein MFR represents a melt flow rate of said copolymer, and d represents a density of said copolymer;
• and
• (E) in the case that said copolymer is melted at 200.degree. C., then slowly cooled to 50.degree. C. at a cooling rate of 0.31.degree. C./min and crystallized to prepare a sheet sample having a thickness of 0.5 mm, a DSC melt-peak pattern of the sample obtained when the sample is heated from 10.degree. to 200.degree. C. at a heating rate of 10.degree. C./min using DSC has two melt peaks, and a ratio (Hh/Hl) of a height of the peak (Hh) on the higher temperature side to a height of the peak (Hl) on the lower temperature side and the density of said copolymer satisfy the following formula:
• <
• Hh/Hl<60d-52.0
• wherein Hh represents a peak height on the higher temperature side, Hl represents a peak height on the lower temperature side, and d represents a density of said copolymer.