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US 5,656,693 AGranted
Thermoplastic elastomers having improved cure
AssigneeExxon Chemical Patents Inc.
InventorsMaria D. Ellul, Donald R. Hazelton, Periagaram S. Ravishankar
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Abstract
Thermoplastic elastomers containing ethylene, alpha-olefin, vinyl norbornene elastomeric polymers provide superior cure levels to thermoplastic elastomers containing ethylene, alpha-olefin, diene monomer elastomeric polymers with other dienes than vinyl norbornene. The elastomeric polymers, along with a thermoplastic, curative, and other components will have cure levels in excess of 95 percent. Lower diene incorporation into the polymer combined with lower curative levels yield a fabricated article with improved resistance to compression set and improved heat aging.
Claims22
A thermoplastic elastomer comprising:
- a) an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer;
- b) a crystalline thermoplastic selected from the group consisting of homopolymers and copolymers of polypropylene, polybutylene, homopolymers and copolymers of ethylene, polyethylene terephthalate, polybutylene terephthalate, polyamides, and mixtures thereof;
- and
- c) a curative comprising an organic peroxide;
- wherein said curative is present in said thermoplastic elastomer in an amount effective to yield a cure level of said elastomeric polymer of at least about 95 percent;
- wherein said elastomeric polymer has a M.sub.w /M.sub.n greater than 6;
- and wherein said elastomeric polymer has a branching index below about 0.6.
4 more elements
A thermoplastic elastomer comprising:
- a) an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer, said elastomeric polymer including:
- i) in the range of about 70 to about 90 mole percent ethylene;
- and
- ii) in the range of from about 0.2 to about 1.5 mole percent vinyl norbornene,
- iii) in the range of from about 10 to about 30 mole percent of said alpha-olefin,
- said mole percents based on the total moles of the elastomeric copolymer;
- and wherein said elastomeric copolymer has a M.sub.w /M.sub.n greater than 6, and a branching index in the range of from about 0.1 to about 0.3,
- b) a crystalline thermoplastic selected from the group consisting of thermoplastic homopolymers and copolymers of propylene, polybutylene, homopolymers and copolymers of ethylene, polyethylene terephthalate, polybutylene terephthalate, polyamides, and mixtures thereof;
- and
- c) a curative comprising an orgain peroxide;
- d) a cure adjuvant;
- and
- wherein said curative and said cure adjuvant are present in said thermoplastic elastomer at an amount effective to yield at least about 95 percent cured elastomeric polymer.
10 more elements
A thermoplastic elastomer comprising:
- a) an ethylene, propylene, vinylnorbornene elastomeric polymer, wherein:
- i) said ethylene is present in said polymer in the range of from about 50 to about 85 mole percent;
- ii) said vinyl norbornene is present in said polymer in the range of from about 0.4 to about 1.5 mole percent;
- iii) said propylene is present in the range of from about 15 to about 50 mole percent;
- said mole percents based on the total moles in said elastomeric polymer;
- iv) said elastomeric polymer has a ML(1+4) at 125.degree. C. above about 20 and a MST(5+4) at 200.degree. C. below about 60 and;
- v) said elastomeric polymer has a M.sub.w /M.sub.n above about 10,
- b) a thermoplastic selected from the group consisting of polypropylene and blends of polypropylene, said thermoplastic having:
- i) a melt flow rate measured according to test method ASTM-D1238 in the range off from about 0.1 to about 30 dg/min;
- and
- c) a curative system, said curative system including .alpha.,.alpha.-bis(tert-butylperoxy)diisopropyl benzene and triallyl cyanurate;
- wherein;
- said thermoplastic is present in said thermoplastic elastomer in the range of from about 20 to about 100 parts per hundred parts of said elastomeric polymer;
- wherein said .alpha.,.alpha.-bis(tert-butylperoxy)diisopropyl benzene and triallyl cyanurate is present in said thermoplastic elastomer in the range of from about 7.times.10.sup.-4 to about 1.5.times.10.sup.-3 mole per hundred parts of said elastomeric polymer;
- and
- wherein said thermoplastic elastomer has a cured polymer portion exceeding about 95 percent.
13 more elements
A method for preparing a thermoplastic elastomer comprising:
- a) masticating
- i) an ethylene, alpha-olefin, vinyl norbornene elastomeric polymer,
- ii) a crystalline thermoplastic present in said thermoplastic elastomer in the range of from about 10 to about 900 parts per hundred parts of said elastomeric polymer;
- and
- iii) a curative comprising an organic peroxide, said curative being present at a level to cure said elastomeric polymer to above about 95 percent, said masticating carried out for a sufficient time to obtain a substantially homogeneous mixture;
- b) adding a cure activator;
- and
- c) masticating a product of (a) and (b) at a temperature and for a time sufficient to yield about 95 percent or greater cure of said elastomeric polymer.
5 more elements
A thermoplastic elastomer comprising:
- a) an ethylene, propylene, vinylnorbornene elastomeric polymer, wherein:
- i) said ethylene is present in said polymer in the range of from about 50 to about 85 mole percent;
- ii) said vinyl norbornene is present in said polymer in the range of from about 0.4 to about 1.5 mole percent;
- iii) said propylene is present in the range of from about 15 to about 50 mole percent;
- said mole percents based on the total moles in said elastomeric polymer;
- iv) said elastomeric polymer has a ML(1+4) at 125.degree. C. above about 20 and a MST(5+4) at 200.degree. C. below about 60;
- v) said elastomeric polymer has a branching index in the range of from about 0.1 to about 0.3;
- and
- vi) said elastomeric polymer has a M.sub.w /M.sub.n above about 10;
- b) a crystalline thermoplastic selected from the group consisting of polypropylene and blends of polypropylene, said thermoplastic having:
- i) a melt flow rate measured according to test method ASTM-D1238 in the range of from about 0.1 to about 30 dg/min;
- and
- c) a curative system, said curative system including .alpha.,.alpha.-bis(tert-butylperoxy)diisopropyl benzene and triallyl cyanurate;
- wherein;
- said thermoplastic is present in said thermoplastic elastomer in the range of from about 20 to about 100 per hundred parts of said elastomeric polymer;
- wherein said .alpha.,.alpha.-bis(tert-butylperoxy)diisopropyl benzene and triallyl cyanurate is present in said thermoplastic elastomer in the range of from about 7.times.10.sup.-4 to about 1.5.times.10.sup.-3 mole per hundred parts of said elastomeric polymer;
- and
- wherein said thermoplastic elastomer has a cured polymer portion exceeding about 95 percent.
15 more elements
Dependencies are inferred from the claim text.