US4684535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Surface treatment of plastics material
Assignee: STC PLC
•
Filing: 1986-07-28
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Granted: 1987-08-04
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Expires: 2006-07-28
Abstract
Abstract Discontinuities, e.g. scratches, in a plastics surface are removed by exposing the surface to a pulsed radio frequency plasma comprising a mixture of argon and hydrogen. After melting has been effected the surface is exposed to an argon plasma to effect cross-linking to form a smooth surface layer.
Inventors
- 👤 Rudolf A. H. Heinecke
- 👤 Suresh M. Ojha
- 👤 Ian P. Llewellyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:35
CPC Classifications
B; B05; B05D; B05D1/00; B05D1/62; B05D3/00; B05D3/14; B05D3/141; B05D3/142; B05D3/144; B29; B29C; B29C59/00; B29C59/14; B05D2201/00; B05D2201/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
111 words
A process for removing discontinuities from a plastics surface by fusion and cross-linking of the surface, the process comprising the steps of: exposing the plastics surfaces to a first pulsed radio frequency plasma comprising argon as the major constituent and up to 30 volume percent of hydrogen, the hydrogen content of the plasma being such that the melting point of the plastics surface is reduced whereby the plastics surface is rendered molten and thereby smoothed and exposed the molten plastics surface to a second pulsed radio frequency plasma comprising argon for a sufficient period of time to effect cross-linking of the molten surface, thereby increasing the melting point of the surface.
Claim 2
Dependent Claim
111 words
A process for removing discontinuities from a plastics surface by fusion and cross-linking of the surface, the process comprising the steps of: exposing the plastics surfaces to a first pulsed radio frequency plasma comprising argon as the major constituent and up to 30 volume percent of hydrogen, the hydrogen content of the plasma being such that the melting point of the plastics surface is reduced whereby the plastics surface is rendered molten and thereby smoothed and exposed the molten plastics surface to a second pulsed radio frequency plasma comprising argon for a sufficient period of time to effect cross-linking of the molten surface, thereby increasing the melting point of the surface.
Claim 3
Dependent Claim
18 words
A process as claimed in claim 1 wherein the plasma contains from 5 to 10 volume percent hydrogen.
Claim 4
Dependent Claim
22 words
A process as claimed in claim 1 wherein the plastics surface is subjected to an energy density of 2 to 3 kw/liter.
Claim 5
Dependent Claim
19 words
A process as claimed in claim 3, wherein the pressure of the plasma is 10 to 200 m torr.
Claim 6
Dependent Claim
16 words
A process as claimed in claim 4, wherein the pulse width is 1 to 5 ms.
Claim 7
Dependent Claim
17 words
A process as claimed in claim 5, wherein the pulse repetition frequency is 5 to 20 Hz.
Claim 8
Dependent Claim
16 words
A process as claimed in claim 1 wherein a coating is subsequently applied to the surface.
Claim 9
Dependent Claim
15 words
A process as claimed in claim 7, wherein said coating is a plasma deposited coating.
Claim 10
Dependent Claim
16 words
A process as claimed in claim 1, wherein a coating is subsequently applied to the surface.
Claim 11
Dependent Claim
15 words
A process as claimed in claim 9, wherein said coating is a plasma deposited coating.
References Cited (Backward Citations)
GB2031439A
Cited
GB2051087A
Cited
GB2061969A
Cited
JPS5734137A
Cited
US4396641A
Cited
US4395434A
Cited
US4337279A
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GB2105729A
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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) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |