US4970043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming thermoplastic material from granular scrap material
Assignee: Individual
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Filing: 1989-02-27
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Granted: 1990-11-13
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Expires: 2009-02-27
Abstract
Abstract A process forming a moldable material from a granular scrap material such as a high grade reground rubber and a thermoplastic polymer such as a butadiene-styrene block copolymer sold under the trademark Kraton-D-3202 by Shell Chemical Company. A substantially uniformly distributed mixture of the reground rubber and the cohesive base material in a ratio of at least about 1:1 is processed under sufficient pressure and temperature to form a semi-stable moldable product. The semi-stable moldable product is then subjected or maintained under sufficient pressure to form a stable moldable product. The ratio of reground rubber to cohesive base material may be 7:3 or higher, while pressure on the semi-stable product may generally be in the range of 1800 psi or higher. The moldable product may be subsequently molded, preferably with high fill velocities and maximum venting.
Inventors
- 👤 Rosetta C. Doan
- 👤 Albert W. Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:23
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/0026; B29B17/0042; B29B9/00; B29B9/02; B29B9/06; B29B9/065; B29C; B29C45/00; B29C45/0013; B29K; B29K2009/00; B29K2009/06; B29K2105/00; B29K2105/26; B29L; B29L2030/00; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10S; Y10S264/00; Y10S264/911; Y10S264/912
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
152 words
A process for forming a stable moldable product comprising: mixing a starting material comprising a high grade reground rubber and a cohesive base material in a ratio such that the starting material is comprised of at least 50% by weight of the reground rubber; placing the starting material under sufficient pressure and temperature for a sufficient residence time to plasticize a significant portion of the cohesive base material while avoiding significant degradation of the materials to form a semi-stable moldable product degradable under atmospheric pressure and having an aggregate interior portion at least partially encapsulated by an outer cover layer; and maintaining the semi-stable moldable product under a sufficiently high pressure while at least partially cooling the semi-stable moldable product to allow the outer cover layer to strengthen and form a stable moldable product, said stable moldable product being able to form a molded product having reduced porosity and generally uniform properties.
Claim 2
Dependent Claim
152 words
A process for forming a stable moldable product comprising: mixing a starting material comprising a high grade reground rubber and a cohesive base material in a ratio such that the starting material is comprised of at least 50% by weight of the reground rubber; placing the starting material under sufficient pressure and temperature for a sufficient residence time to plasticize a significant portion of the cohesive base material while avoiding significant degradation of the materials to form a semi-stable moldable product degradable under atmospheric pressure and having an aggregate interior portion at least partially encapsulated by an outer cover layer; and maintaining the semi-stable moldable product under a sufficiently high pressure while at least partially cooling the semi-stable moldable product to allow the outer cover layer to strengthen and form a stable moldable product, said stable moldable product being able to form a molded product having reduced porosity and generally uniform properties.
Claim 3
Dependent Claim
22 words
A process according to claim 1 wherein the starting material is comprised of at least 70% by weight of the reground rubber.
Claim 4
Dependent Claim
15 words
A process according to claim 1 wherein the cohesive base material comprises a thermoplastic polymer.
Claim 5
Dependent Claim
14 words
A process according to claim 3 wherein the thermoplastic polymer comprises a thermoplastic rubber.
Claim 6
Dependent Claim
20 words
A process according to claim 1 wherein the pressure on the semi-stable moldable product is at least about 1100 psig.
Claim 7
Dependent Claim
20 words
A process according to claim 1 wherein the pressure on the semi-stable moldable product is at least about 1800 psig.
Claim 8
Dependent Claim
37 words
A process according to claim 1 wherein the step of mixing the materials is done in a screw extruder having a feed section, a pump section and a metering section, each section comprising a plurality of flights.
Claim 9
Dependent Claim
113 words
A process according to claim 1 further comprising molding of the stable moldable end product to form a molded product comprising the steps of: heating the stable moldable product sufficiently to form a plasticized moldable material while under sufficient pressure to avoid significant deterioration of the plasticized moldable material; injecting the plasticized moldable material into a mold at a sufficiently high velocity to avoid significant localized cooling; subsequently at least partially cooling the plasticized moldable material in the mold while maintaining pressure on the material sufficient to avoid significant deterioration of the material; and further cooling the material to the extent required to form a relatively nonporous molded product having generally uniform properties.
Claim 10
Dependent Claim
48 words
A process according to claim 8 wherein the step of cooling the plasticized moldable material in the mold occurs by placing a liquid cooling medium in heat exchange relation with the plasticized moldable material, the cooling medium being in a temperature range of about 65° to 80° F.
Claim 11
Dependent Claim
19 words
A process according to claim 9 wherein the molding fill velocity is greater than about three inches per second.
Claim 12
Dependent Claim
123 words
A process for forming a stable moldable product comprising: feeding a high grade reground rubber and a cohesive base material in predetermined quantities without substantially premixing to a feed zone for mixing to form a uniformly distributed mixture comprising at least 50% by weight of the reground rubber; compressing and heating the mixture for a sufficient time to form a plastic stream; passing the plastic stream under sufficient temperature and pressure through a metering zone until a semi-stable moldable product is formed; maintaining the semi-stable product under a sufficiently high pressure while at least partially cooling the semi-stable moldable product to form a stable product, said stable product being able to form a molded product having relatively low porosity and generally uniform properties.
Claim 13
Dependent Claim
123 words
A process for forming a stable moldable product comprising: feeding a high grade reground rubber and a cohesive base material in predetermined quantities without substantially premixing to a feed zone for mixing to form a uniformly distributed mixture comprising at least 50% by weight of the reground rubber; compressing and heating the mixture for a sufficient time to form a plastic stream; passing the plastic stream under sufficient temperature and pressure through a metering zone until a semi-stable moldable product is formed; maintaining the semi-stable product under a sufficiently high pressure while at least partially cooling the semi-stable moldable product to form a stable product, said stable product being able to form a molded product having relatively low porosity and generally uniform properties.
Claim 14
Dependent Claim
19 words
A process according to claim 11 wherein the mixture comprises at least 70% by weight of the reground rubber.
Claim 15
Dependent Claim
19 words
A process according to claim 11 wherein the pressure on the semi-stable product is at least about 1,100 psig.
Claim 16
Dependent Claim
20 words
A process according to claim 11 wherein the reground rubber is a high grade reground rubber obtained from tire peels.
Claim 17
Dependent Claim
15 words
A process according to claim 11 wherein the cohesive base material comprises a thermoplastic rubber.
Claim 18
Dependent Claim
151 words
A process for forming a stable moldable product comprising: feeding a high grade reground rubber material and a thermoplastic rubber material comprising a styrene-butadiene block copolymer to a feeding zone to form a uniformly distributed mixture comprising at least 70% by weight of reground rubber, while applying heat to the materials as the materials are fed and mixed; compressing the mixture at a pressure in the range of 1,100 to 1,800 psig or higher while heating the mixture to a temperature in the range of 350°-500° F. for a sufficient time to form a semi-stable moldable product; and maintaining the semi-stable moldable product under a pressure in excess of about 1,800 psig while partially cooling the semi-stable moldable product for at least one-half of its cooling cycle to form a stable moldable product said stable moldable product being able to form a molded product having reduced porosity and generally uniform properties.
Claim 19
Dependent Claim
151 words
A process for forming a stable moldable product comprising: feeding a high grade reground rubber material and a thermoplastic rubber material comprising a styrene-butadiene block copolymer to a feeding zone to form a uniformly distributed mixture comprising at least 70% by weight of reground rubber, while applying heat to the materials as the materials are fed and mixed; compressing the mixture at a pressure in the range of 1,100 to 1,800 psig or higher while heating the mixture to a temperature in the range of 350°-500° F. for a sufficient time to form a semi-stable moldable product; and maintaining the semi-stable moldable product under a pressure in excess of about 1,800 psig while partially cooling the semi-stable moldable product for at least one-half of its cooling cycle to form a stable moldable product said stable moldable product being able to form a molded product having reduced porosity and generally uniform properties.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |