US3916050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyurethane sandblast stencil
Assignee: 3M Co
•
Filing: 1972-11-15
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Granted: 1975-10-28
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Expires: 1992-11-15
Abstract
Abstract Sheet material for making sandblast stencils is simply and predictably prepared by blending polyurethane forming components and kaolin or similarly reinforcing filler. A small amount of wax is preferably incorporated to improve cuttability. Such structures typically have on one face a layer of pressuresensitive adhesive protected by a removable liner.
Inventors
- 👤 George A Kurhajec
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:49
CPC Classifications
C; C08; C08L; C08L75/00; C08L75/04; B; B41; B41N; B41N1/00; B41N1/24; C08K; C08K3/00; C08K3/34; C08L91/00; C08L91/06; Y; Y10; Y10T; Y10T428/00; Y10T428/14; Y10T428/1419; Y10T428/31504; Y10T428/31551; Y10T428/31609
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
144 words
IN A LAMINAR SANDBAST STENCIL SHEET OF THE TYPE COMPRISING A FILLED SELF-SUPPORTING RUBBERY LAYER HAVING A FIRST PRESSURESENSITIVE ADHESIVE LAYER ON ONE SIDE, THE IMPROVEMENT WHEREIN SAID FILLED RUBBERY LAYER IS A POLYURETHANE REACTION PRODUCT OF COMPONENTS COMPRISING (1) A MIXTURE OF POLYOLS AND POLYISOCYANATES HAVING AN OH:NCO RTIO IN THE RANGE OF ABOUT 1.0 TO 1.2, AND (2) A PARTICULATE KAOLIN FILLER, SAID FILLER CONSTITUTIN ABOUT 1/5 TO ABOUT 1/3 THE VOLUME OF SAID RUBBERT LAYER SAID REACTION PRODUCT HAVING AN ELONGATION AT BREAK ON THE ORDER OF 100 - 1000 PERCENT, A TENSILE STRENGTH OF 5-40 POUNDS PER INCH WIDTH, A TEAR RESISTANCE OF 1.0-4.0 POUNDS A SHORE A-2 HARDNESS OF 30-75,.9 - 1.8 URETHANE GROUPS PER1000 GRAMS OF THE POLYURETHAN PORTION OF SAID REACTION PRODUCT, AND A MOLCULAR WEIGHT BETWEEN URETHANE-CONTAINING CROSSLAINKS AIN THE APPROXIMATE RANGE OF 2000 TO 10,000,
Claim 2
Dependent Claim
144 words
IN A LAMINAR SANDBAST STENCIL SHEET OF THE TYPE COMPRISING A FILLED SELF-SUPPORTING RUBBERY LAYER HAVING A FIRST PRESSURESENSITIVE ADHESIVE LAYER ON ONE SIDE, THE IMPROVEMENT WHEREIN SAID FILLED RUBBERY LAYER IS A POLYURETHANE REACTION PRODUCT OF COMPONENTS COMPRISING (1) A MIXTURE OF POLYOLS AND POLYISOCYANATES HAVING AN OH:NCO RTIO IN THE RANGE OF ABOUT 1.0 TO 1.2, AND (2) A PARTICULATE KAOLIN FILLER, SAID FILLER CONSTITUTIN ABOUT 1/5 TO ABOUT 1/3 THE VOLUME OF SAID RUBBERT LAYER SAID REACTION PRODUCT HAVING AN ELONGATION AT BREAK ON THE ORDER OF 100 - 1000 PERCENT, A TENSILE STRENGTH OF 5-40 POUNDS PER INCH WIDTH, A TEAR RESISTANCE OF 1.0-4.0 POUNDS A SHORE A-2 HARDNESS OF 30-75,.9 - 1.8 URETHANE GROUPS PER1000 GRAMS OF THE POLYURETHAN PORTION OF SAID REACTION PRODUCT, AND A MOLCULAR WEIGHT BETWEEN URETHANE-CONTAINING CROSSLAINKS AIN THE APPROXIMATE RANGE OF 2000 TO 10,000,
Claim 3
Dependent Claim
36 words
The stencil sheet of claim 1 wherein the kaolin constitutes about 1/3 the volume of the rubbery layer and the tensile strength of the rubbery layer is in the range of 10-30 lbs. per inch width.
Claim 4
Dependent Claim
20 words
The stencil sheet of claim 1 wherein the rubbery layer contains up to 10 volume percent lubricant to facilitate cutting.
Claim 5
Dependent Claim
22 words
The stencil sheet of claim 3 wherein the lubricant is a paraffin wax having a melting point in the range of 100*-150*F.
Claim 6
Dependent Claim
20 words
The stencil sheet of claim 1 wherein the first pressure-sensitive adhesive layer is protectively covered by a removable release liner.
Claim 7
Dependent Claim
44 words
THE STENCIL SHEET OF CLAIM 1 WHEREIN A POLYMERIC FILM IS ADHERED TO THE EXPOSED SURFCE OF SAID FIRST PRESSURE-SENSITIVE ADHESIVE LAYER AND A SECOND PRESSURE-SENSITIVE ADHESIVE LAYER OVERLIES SAID FILM, SAI SECOND PRESSURE-SENSITIVE ADHESIVE LAYER BEING PROTECTIVELY COVERED BY A REMOVABLE RELEASE LINER,
Claim 8
Dependent Claim
15 words
The stencil sheet of claim 1 wherein the polyols comprise a diol and a triol.
Claim 9
Dependent Claim
17 words
The stencil sheet of claim 1 wherein the Shore A-2 hardness is in the range of 45-70.
References Cited (Backward Citations)
CA757807A
Cited
US3201136A
Cited
US3583945A
Cited
US3592787A
Cited
US3714110A
Cited
US3492255A
Cited
US3579926A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-27 | 1979-04-28 | 1979-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-27 | 1983-04-28 | 1983-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-27 | 1987-04-28 | 1987-10-28 | $7700.00 | Window Closed / Lapsed |