Crosslinked polyethylene composition having improved processability

Patent metadata

Field	Value
Publication number	US-9388296-B2
Application number	US-201214405220-A
Country	US
Kind code	B2
Filing date	Jun 4, 2012
Priority date	Jun 4, 2012
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

Disclosed in the present invention is a crosslinked polyethylene composition having improved processability comprises: 100 parts by weight of polyethylene, 0.03-5 parts by weight of crosslinking agent, 0.03-5 parts by weight of crosslinking promoter, and 0.01-1.5 parts by weight of free radical inhibitor, wherein the polyethylene is a copolymer and/or homopolymer containing at least 90 wt. % of vinyl and at least one C 3 -C 8 α-alkenyl, and has a density in the range of 0.920-0.970 g/cm 3 , a melt index in the range of 2.5-17.5 g/10 min; the crosslinking agent is a peroxide crosslinking agent; the crosslinking promoter is an organic substance containing maleimido, (meth)acrylate group, and/or allyl, and/or a polymer containing more than 50% of vinyl; the free radical inhibitor is an organic antioxidant, a quinhydrone and/or a substituted quinhydrone. The crosslinked polyethylene composition of the present invention has a crosslinking efficiency index of more than 1,100 Nm/g and a δ torque value of more than 10 Nm at the temperature of 200° C., a significantly higher safety process temperature and a significantly improved crosslinking retardation time compared to the conventional crosslinked polyethylene composition, which make it especially be suitable for the production of rotational molding articles.

First claim

The invention claimed is:

1. A crosslinked polyethylene composition wherein the composition is prepared by combining: 100 parts by weight of polyethylene, 0.03-5 parts by weight of crosslinking agent, 0.03-5 parts by weight of crosslinking promoter, and 0.01-1.5 parts by weight of free radical inhibitor, wherein the polyethylene is a copolymer and/or homopolymer containing at least 90 wt. % of vinyl and at least one C 3 -C 8 α-alkenyl, has a density in the range of 0.935-0.960 g/cm 3 , and a melt index in the range of 2.5-17.5 g/10 min at 190° C./2.16 kg; the crosslinking agent is a peroxide crosslinking agent; the crosslinking promoter is an organic substance containing maleimido, (meth)acrylate group, and/or allyl, and/or a polymer containing more than 50% of vinyl; the free radical inhibitor is hydroquinone and/or a substituted hydroquinone selected from the group consisting of 4,4′-thio-bis(6-tert-butyl-3-methyl-phenol), 2,2′-thio-bis(4-methyl-6-tert-butylphenol), 2,2′-thio-bis(4-chloro-6-isopropyl-3-methylphenol), 4,4′-thio-bis(6-tert-butyl-m-cresol), 4,4′-thio-bis(2-methyl-6-tert-butylphenol), 4,4′-thio-bis(2-tert-butyl-5-methylphenol), and mixtures thereof, and
the crosslinked polyethylene composition has a crosslinking efficiency index of more than 1,100 Nm/g and a δ torque value of more than 10 Nm at the temperature of 200° C. and 40 rpm.

2. The crosslinked polyethylene composition according to claim 1 , wherein the composition is prepared by combining: 100 parts by weight of polyethylene, 0.1-3 parts by weight of crosslinking agent, 0.1-3 parts by weight of crosslinking promoter, and 0.03-1.0 parts by weight of free radical inhibitor.

3. The crosslinked polyethylene composition according to claim 2 , wherein the composition is prepared by combining: 100 parts by weight of polyethylene, 0.3-2 parts by weight of crosslinking agent, 0.3-2 parts by weight of crosslinking promoter, and 0.1-0.8 parts by weight of free radical inhibitor.

4. The crosslinked polyethylene composition according to claim 1 , wherein the polyethylene has a melt index in the range of 4-15 g/10 min at 190° C./2.16 kg.

5. The crosslinked polyethylene composition according to claim 1 , wherein the polyethylene has a melt index in the range of 6-10 g/10 min at 190° C./2.16 kg.

6. The crosslinked polyethylene composition according to claim 1 , wherein the polymer containing more than 50% of vinyl is 1,2-polybutadiene.

7. The crosslinked polyethylene composition according to claim 1 , wherein said peroxide crosslinking agent is selected from the group consisting of 1,1-di(tert-butylperoxy)-3,3,5 trimethyl cyclohexane; 2,7-dimethyl-2,7-di(tert-butylperoxy)octadiyne-3,5; 2,7-dimethyl-2,7-di(peroxyethyl carbonate)octadiyne-3,5; 3,6-dimethyl-3,6-di(peroxyethyl carbonate)octyne-4; 3,6-dimethyl-3,6-di(tert-butylperoxy)octyne-4; 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3; 2,5-dimethyl-2,5-di(peroxy n-propyl carbonate) hexyne-3; 2,5-dimethyl-2,5-di(peroxy isobutyl carbonate)-hexyne-3; 2,5-dimethyl-2,5-di(peroxyethyl carbonate)hexyne-3; 2,5-dimethyl-2,5-di(alpha-cumyl peroxy) hexyne-3; 2,5-dimethyl-2,5-di(peroxy betachloroethyl carbonate) hexyne-3; 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3 (DTBH); butyl-4,4-di(tert-butylperoxy)valerate; di(2,4-dichlorobenzoyl) peroxide; di(4-methylbenzoyl) peroxide; di (tert-butylperoxy isopropyl)benzene; dibenzoyl peroxide; dicumyl peroxide (DCP); ditert-butyl peroxide; tert-butylcumyl peroxide; tert-butyl peroxy-3,5,5-trimethylhexanoate; tert-butylperoxy benzoate; and tert-butylperoxy-2-ethylhexyl carbonate.

8. The crosslinked polyethylene composition according to claim 1 , wherein said crosslinking promoter is selected from the group consisting of cis-1,2-polybutadiene (1,2-BR); diallyl terephthalate (DATP); triallyl cyanurate (TAC); and triallyl isocyanurate (TAIC).

Assignees

• Chen Xuelian
• Liang Wenbin
• Niu Yanhua
• Lai Shih-Yaw
• Nat Inst Clean & Low Carbon Energy
• Shenhua Group Corp Ltd

Inventors

• Chen Xuelian
• Liang Wenbin
• Niu Yanhua
• Lai Shih-Yaw

Classifications

• C08L2207/062

  HDPE · CPC title

• C08L23/08

  Copolymers of ethene (C08L23/16 takes precedence) · CPC title

• C08K5/34924

  containing cyanurate groups; Tautomers thereof · CPC title

• C08K5/375

  containing six-membered aromatic rings {(C08K5/3725 takes precedence)} · CPC title

• C08K5/13

  Phenols; Phenolates · CPC title