US4185070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for injection molding thermoplastic articles with reduced combustibility
Assignee: Union Carbide Corp
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Filing: 1977-11-10
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Granted: 1980-01-22
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Expires: 1997-11-10
Abstract
Abstract A process is disclosed for the production of injection molded thermoplastic articles having reduced combustibility comprising: maintaining a mold cavity at a pre-selected back pressure sufficiently high to substantially prevent foaming of a thermoplastic melt to be injected therein; injecting thermoplastic melt into said mold cavity under a pressure in excess of said back pressure to fill said mold cavity; said thermoplastic melt containing from about 50 to 70% by weight of alumina trihydrate and from about 1 to 12% by weight of water as a liquid processing aid.
Inventors
- 👤 Richard G. Angell, Jr.
- 👤 Laurence H. Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:58
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/02; B29C44/10; B29C44/105; C; C08; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
The process for the production of injection molded thermoplastic articles having reduced combustibility comprising: maintaining a mold cavity at a preselected back pressure sufficiently high to substantially prevent foaming of a thermoplastic melt to be introduced therein; injecting thermoplastic melt into said mold cavity under a pressure in excess of said back pressure to fill said mold cavity; said thermoplastic melt containing from about 50 to 70% by weight of alumina trihydrate and from about 1 to 12% by weight of water as a liquid processing aid thereby permitting increased rate of thermoplastic melt flow while filling said mold cavity.
Claim 2
Dependent Claim
100 words
The process for the production of injection molded thermoplastic articles having reduced combustibility comprising: maintaining a mold cavity at a preselected back pressure sufficiently high to substantially prevent foaming of a thermoplastic melt to be introduced therein; injecting thermoplastic melt into said mold cavity under a pressure in excess of said back pressure to fill said mold cavity; said thermoplastic melt containing from about 50 to 70% by weight of alumina trihydrate and from about 1 to 12% by weight of water as a liquid processing aid thereby permitting increased rate of thermoplastic melt flow while filling said mold cavity.
Claim 3
Dependent Claim
22 words
The process in accordance with claim 1, wherein said thermoplastic melt contains from about 55 to 65% by weight of alumina trihydrate.
Claim 4
Dependent Claim
19 words
The process in accordance with claim 2, wherein said thermoplastic melt contains about 60% by weight of alumina trihydrate.
Claim 5
Dependent Claim
15 words
The process in accordance with claim 1, wherein said thermoplastic melt is a polyolefin-containing melt.
Claim 6
Dependent Claim
29 words
The process in accordance with claim 1, wherein said thermoplastic melt is introduced into said mold cavity at a pressure of the order of about 2500 to 3500 psi.
Claim 7
Dependent Claim
23 words
The process in accordance with claim 1, wherein said mold cavity is maintained at a back pressure of about 200 to 450 psi.
Claim 8
Dependent Claim
15 words
The process in accordance with claim 4, wherein said polyolefin-containing melt is a polyethylene-containing melt.
Claim 9
Dependent Claim
16 words
The process in accordance with claim 7, wherein said polyethylene-containing melt is a high density polyethylene.
Claim 10
Dependent Claim
24 words
The process in accordance with claim 7, wherein said melt consists essentially of a polyethylene, alumina trihydrate and water as a liquid processing aid.
Claim 11
Dependent Claim
25 words
The process in accordance with claim 8, wherein said melt consists essentially of high density polyethylene, alumina trihydrate and water as a liquid processing aid.
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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) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |