US4061694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low temperature impact strength molding compositions
Assignee: Dart Industries Inc
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Filing: 1976-12-21
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Granted: 1977-12-06
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Expires: 1996-12-21
Abstract
Abstract Polypropylene molding compositions of improved impact strength are obtained by subjecting certain block copolymers of ethylene and propylene to controlled oxidative degradation.
Inventors
- 👤 Eugene Gennaro Castagna
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:46
CPC Classifications
C; C08; C08L; C08L23/00; C08L23/26; C08L23/30; C08F; C08F8/00; C08F8/50; C08F2800/00; C08F2800/20; C08F2810/00; C08F2810/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
171 words
A polypropylene molding resin of improved low temperature impact strength obtained in a process comprising I. providing a block copolymer having a melt flow rate in the range of from about 0.5 to about 1.5 grams per 10 minutes at 230° C and containing a. from about 60 to about 95 percent by weight of a polypropylene block and b. from about 5 to about 40 percent by weight of a block of a random copolymer of ethylene and another α-olefin, wherein the content of ethylene derived units in said random copolymer block ranges between 30 and 60 weight percent, Ii. contacting said block copolymer with an oxygen containing compound selected from air, elemental oxygen, inorganic peroxide, organic peroxide, or mixtures thereof; melting and working the mixture of oxygen containing compound and block copolymer in a high shear zone to subject the mixture to substantial oxidative degradation, and Iii. recovering a polymer product having a melt flow rate which is higher than that of the block copolymer provided in Step I.
Claim 2
Dependent Claim
171 words
A polypropylene molding resin of improved low temperature impact strength obtained in a process comprising I. providing a block copolymer having a melt flow rate in the range of from about 0.5 to about 1.5 grams per 10 minutes at 230° C and containing a. from about 60 to about 95 percent by weight of a polypropylene block and b. from about 5 to about 40 percent by weight of a block of a random copolymer of ethylene and another α-olefin, wherein the content of ethylene derived units in said random copolymer block ranges between 30 and 60 weight percent, Ii. contacting said block copolymer with an oxygen containing compound selected from air, elemental oxygen, inorganic peroxide, organic peroxide, or mixtures thereof; melting and working the mixture of oxygen containing compound and block copolymer in a high shear zone to subject the mixture to substantial oxidative degradation, and Iii. recovering a polymer product having a melt flow rate which is higher than that of the block copolymer provided in Step I.
Claim 3
Dependent Claim
23 words
A polypropylene molding resin according to claim 1, wherein the polypropylene block is a preblock and the random copolymer block is a postblock.
Claim 4
Dependent Claim
16 words
A polypropylene molding resin according to claim 2, wherein the polypropylene block is a polypropylene homopolymer.
Claim 5
Dependent Claim
35 words
A polypropylene molding resin according to claim 2, wherein the polypropylene preblock is a random copolymer of propylene and no more than 5 mole percent of another α-olefin having from 2 to 8 carbon atoms.
Claim 6
Dependent Claim
21 words
A polypropylene molding resin according to claim 2, wherein the random copolymer postblock is a random copolymer of ethylene and propylene.
Claim 7
Dependent Claim
29 words
A polypropylene molding resin according to claim 5, wherein the content of ethylene derived units in said random copolymer postblock is between about 40 and about 50 weight percent.
Claim 8
Dependent Claim
30 words
A polypropylene molding resin according to claim 5, wherein the random copolymer postblock represents on the average from about 20 to about 30 percent by weight of the block copolymer.
Claim 9
Dependent Claim
33 words
A polypropylene molding resin according to claim 5, wherein the block copolymer of Step I has a melt flow rate in the range from about 0.6 to about 1.3 grams per 10 minutes.
Claim 10
Dependent Claim
15 words
A polypropylene molding resin according to claim 2, wherein the oxygen containing compound is air.
Claim 11
Dependent Claim
27 words
A polypropylene molding resin according to claim 2, wherein the temperature of the melt of Step II is maintained between about 350° F and about 650° F.
Claim 12
Dependent Claim
27 words
A polypropylene molding resin according to claim 2, wherein the temperature of the melt of Step II is maintained between about 400° F and about 550° F.
Claim 13
Dependent Claim
37 words
A polypropylene molding resin according to claim 2, wherein the oxygen containing compound is a mixture of gaseous oxygen and from about 0.01% and about 0.1% of a peroxide based on the weight of the block copolymer.
Claim 14
Dependent Claim
31 words
A polypropylene molding resin according to claim 2, wherein the melt flow rate of the recovered polymer product is at least double that of the block copolymer provided in Step I.
Claim 15
Dependent Claim
29 words
A polypropylene molding resin according to claim 13, wherein the melt flow rate of the recovered polymer product is between about 2 and about 10 grams per 10 minutes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-05 | 1981-06-06 | 1981-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-05 | 1985-06-06 | 1985-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-05 | 1989-06-06 | 1989-12-06 | $7700.00 | Window Closed / Lapsed |