Patent US1018509A successfully refreshed from Google Patents.
US5709931A
Expired / Lapsed
US
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Release liners for production of molded products
Assignee: Ahlstrom Filtration Inc
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Filing: 1995-08-09
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Granted: 1998-01-20
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Expires: 2015-08-09
Abstract
Abstract A mold release liner for a heated pressure mold for making products such as printed circuit boards is preferably made without polymer films or chemical release agents utilizing two or more wet-laid fiber layers of cellulose or cellulose derivative fibers (such as wood, cotton, cellulose acetate, or rayon fibers, or mixtures of these). The first layer has a sufficiently low density so that it acts as a cushion and absorbs deformation when used as a release liner in the mold (typically it has a thickness of between 8-250 mils, most desirably 40-90 mils, and a basis weight of about 25-350 pounds per ream, most desirably 130-160 pounds per ream). A second layer is of much higher density than the first layer and readily releases from the molds, for example comprising condenser tissue or a similar product, having a thickness of between 0.5-10 mils and a basis weight of 4-50 pounds per ream of 500 sheets. The first and second layers are in face-to-face engagement with each other, and may be adhesively laminated together with sheet, spray, liquid, or powder adhesive. A third layer, substantially like the second layer but on the opposite side of the first face, may also be provided.
Inventors
- 👤 John S. Baumgardner
- 👤 Merle W. Barclay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:18
CPC Classifications
B; B32; B32B; B32B5/00; B32B5/22; B32B5/24; B32B5/26; B29; B29C; B29C33/00; B29C33/56; B29C33/68; B32B23/00; B32B23/10; B32B7/00; B32B7/04; B32B7/12; B32B2262/00; B32B2262/06; B32B2262/062; B32B2262/067; H; H05; H05K; H05K3/00; H05K3/02; H05K3/022; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/24992; Y10T428/31504; Y10T428/31971; Y10T428/31975; Y10T428/31978; Y10T428/31982; Y10T442/00; Y10T442/60; Y10T442/647; Y10T442/651
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
103 words
A heat and pressure mold release liner comprising: a first dry-laid or wet-laid fiber layer of cellulose or cellulose-derivative fibers, said first layer having a thickness of between 8-250 mils and a basis weight of 25-350 pounds per ream of 500 20 inch by 20 inch sheets; a second wet-laid fiber layer of cellulose or cellulose-derivative fibers of higher density than said first layer, said second layer having a thickness of between 0.5-10 mils and a basis weight of 4-50 pounds per ream of 500 20 inch by 20 inch sheets; and said first and second layers in face-to-face engagement with each other.
Claim 2
Dependent Claim
103 words
A heat and pressure mold release liner comprising: a first dry-laid or wet-laid fiber layer of cellulose or cellulose-derivative fibers, said first layer having a thickness of between 8-250 mils and a basis weight of 25-350 pounds per ream of 500 20 inch by 20 inch sheets; a second wet-laid fiber layer of cellulose or cellulose-derivative fibers of higher density than said first layer, said second layer having a thickness of between 0.5-10 mils and a basis weight of 4-50 pounds per ream of 500 20 inch by 20 inch sheets; and said first and second layers in face-to-face engagement with each other.
Claim 3
Dependent Claim
18 words
A release liner as recited in claim 1 further comprising adhesive laminating said first and second layers together.
Claim 4
Dependent Claim
25 words
A release liner as recited in claim 2 wherein said adhesive comprises polyolefin, polyester, hot melt, or starch, in sheet, spray, liquid, or powder form.
Claim 5
Dependent Claim
76 words
A release liner as recited in claim 3 further comprising a third wet-laid fiber layer of cellulose or cellulose-derivative fibers having a density greater than that of said first layer, said third layer having a thickness of between 0.5-10 mils, and a basis weight of 4-50 pounds per ream of 500 20 inch by 20 inch sheets, said third layer in face-to-face engagement with said first layer on the opposite face thereof from said second layer.
Claim 6
Dependent Claim
21 words
A release liner as set forth in claim 4 further comprising an adhesive laminating said third layer to said first layer.
Claim 7
Dependent Claim
33 words
A release liner as set forth in claim 5 wherein said cellulose or cellulose-derivative fibers are cotton, vegetable, cellulose acetate, or rayon fibers, or mixtures thereof with each other, or with wood fibers.
Claim 8
Dependent Claim
18 words
A release liner as recited in claim 5 wherein each of said layers has a substantially uniform density.
Claim 9
Dependent Claim
29 words
A release liner as recited in claim 4 wherein said first layer has a thickness of about 40-90 mils, and a basis weight of about 130-160 pounds per ream.
Claim 10
Dependent Claim
29 words
A release liner as recited in claim 8 wherein said density of each of said second and third layers is at least two times that of said first layer.
Claim 11
Dependent Claim
25 words
A release liner as recited in claim 5 consisting of the recited elements, said release liner being devoid of polymeric films or chemical release agents.
Claim 12
Dependent Claim
35 words
A release liner as recited in claim 1 wherein said second layer includes other fibers in addition to said cellulose or cellulose-derivative fibers which enhance the release properties of said second layer from a mold.
Claim 13
Dependent Claim
76 words
A release liner as recited in claim 1 further comprising a third wet-laid fiber layer of cellulose or cellulose-derivative fibers having a density greater than that of said first layer, said third layer having a thickness of between 0.5-10 mils, and a basis weight of 4-50 pounds per ream of 500 20 inch by 20 inch sheets, said third layer in face-to-face engagement with said first layer on the opposite face thereof from said second layer.
Claim 14
Dependent Claim
33 words
A release liner as set forth in claim 1 wherein said cellulose or cellulose-derivative fibers are cotton, vegetable, cellulose acetate, or rayon fibers, or mixtures thereof with each other, or with wood fibers.
Claim 15
Dependent Claim
29 words
A release liner as recited in claim 1 wherein said first layer has a thickness of about 40-90 mils, and a basis weight of about 130-160 pounds per ream.
Claim 16
Dependent Claim
24 words
A release liner as recited in claim 1 consisting of the recited elements, no polymeric film or fibers or chemical release agents being provided.
Claim 17
Dependent Claim
13 words
A release liner as recited in claim 2 wherein said adhesive comprises polyamide.
Claim 18
Dependent Claim
18 words
A release liner as set forth in claim 5 wherein said cellulose or cellulose-derivative fibers include wood fibers.
Claim 19
Dependent Claim
18 words
A release liner as set forth in claim 1 wherein said cellulose or cellulose-derivative fibers include wood fibers.
Claim 20
Dependent Claim
13 words
A release liner as recited in claim 18 wherein said adhesive comprises polyamide.
Claim 21
Dependent Claim
76 words
A release liner as recited in claim 16 further comprising a third wet-laid fiber layer of cellulose or cellulose-derivative fibers having a density greater than that of said first layer, said third layer having a thickness of between 0.5-10 mils, and a basis weight of 4-50 pounds per ream of 500 20 inch by 20 inch sheets, said third layer in face-to-face engagement with said first layer on the opposite face thereof from said second layer.
Claim 22
Dependent Claim
21 words
A release liner as set forth in claim 20 further comprising an adhesive laminating said third layer to said first layer.
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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) | 2001-01-19 | 2001-07-21 | 2002-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-19 | 2005-07-21 | 2006-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-19 | 2009-07-21 | 2010-01-20 | $7700.00 | Window Closed / Lapsed |