US4753838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polishing sheet material and method for its production
Assignee: Individual
•
Filing: 1987-07-30
•
Granted: 1988-06-28
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Expires: 2007-07-30
Abstract
Abstract A process and product by process of making a polishing sheet material especially useful in the polishing of silicon wafer is disclosed. There is known a process of producing a poromeric suede-like polyurethane layer which comprises applying a solution of polyurethane on an impermeable synthetic resin film, subjecting the polyurethane layer to wet coagulation to form a honeycomb-like cellular structure of polyurethane on the synthetic resin film, removing the synthetic resin film from the cellular polyurethane layer, and abrading a thin surface skin of the cellular layer to form the poromeric suede-like polyurethane layer. In the present invention, a supporting layer made of a non-poromeric, soft synthetic resin sheet having good flatness is joined to a reverse side of the suede-like polyurethane layer to form a polishing sheet material.
Inventors
- 👤 Tsuguji Kimura
- 👤 Shinichi Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:04
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/70; H10P72/74; H10P72/7402; A; A47; A47L; A47L13/00; A47L13/10; A47L13/16; B; B24; B24B; B24B7/00; B24B7/20; B24B7/22; B24B7/228; B24D; B24D11/00; B24D3/00; B29; B29C; B29C44/00; B29K; B29K2075/00; B29L; B29L2031/00; B29L2031/736; H10P72/7416; Y; Y10; Y10S; Y10S428/00; Y10S428/904; Y10T; Y10T428/00; Y10T428/23907; Y10T428/2395; Y10T428/24; Y10T428/24479; Y10T428/24496; Y10T428/24504; Y10T428/24512; Y10T428/249921; Y10T428/249953; Y10T428/249987; Y10T428/249991; Y10T428/249992; Y10T428/31
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
94 words
A process of producing a polishing sheet material comprising the steps of: applying a solution of polyurethane on an impermeable synthetic resin film; subjecting the polyurethane layer to wet coagulation to form a honeycomb-like cellular structure of polyurethane on the synthetic resin film; removing the synthetic resin film from the cellular polyurethane layer; abrading a thin surface skin of the cellular layer to form a poromeric suede-like polyurethane layer; and joining a supporting layer made of a nonporomeric, soft synthetic resin sheet having good flatness to a reverse side of the suede-like polyurethane layer.
Claim 2
Dependent Claim
94 words
A process of producing a polishing sheet material comprising the steps of: applying a solution of polyurethane on an impermeable synthetic resin film; subjecting the polyurethane layer to wet coagulation to form a honeycomb-like cellular structure of polyurethane on the synthetic resin film; removing the synthetic resin film from the cellular polyurethane layer; abrading a thin surface skin of the cellular layer to form a poromeric suede-like polyurethane layer; and joining a supporting layer made of a nonporomeric, soft synthetic resin sheet having good flatness to a reverse side of the suede-like polyurethane layer.
Claim 3
Dependent Claim
20 words
The process according to claim 1, wherein said non-poromeric, soft synthetic resin sheet comprises a sheet of soft polyvinyl chloride.
Claim 4
Dependent Claim
26 words
The process according to claim 1, which process further including the step of applying an adhesive to the exposed side of the soft synthetic resin sheet.
Claim 5
Dependent Claim
21 words
The process according to claim 3, which process further including the step of applying a release paper over said adhesive coating.
Claim 6
Dependent Claim
12 words
A polishing sheet material produced by the process according to claim 1.
Claim 7
Dependent Claim
12 words
A polishing sheet material produced by the process according to claim 3.
Claim 8
Dependent Claim
12 words
A polishing sheet material produced by the process according to claim 4.
References Cited (Backward Citations)
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US3284274A
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US3577507A
Cited
US3524791A
Cited
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Cited
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Cited
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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) | 1991-06-28 | 1991-12-28 | 1992-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-28 | 1995-12-28 | 1996-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-28 | 1999-12-28 | 2000-06-28 | $7700.00 | Window Closed / Lapsed |