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US4698267A
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High density para-aramid papers
Assignee: EIDP Inc
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Filing: 1986-03-13
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Granted: 1987-10-06
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Expires: 2006-03-13
Abstract
Abstract High density para-aramid papers comprising 5 to 25 percent, by weight, binder and an amount of para-aramid fibers selected from the group consisting of para-aramid pulp, para-aramid floc and mixtures thereof, compacted to provide a volume percent para-aramid fiber of at least 53 minus 0.13 times the volume percent floc in the paper are useful in the preparation of circuit board substrates having a low coefficient of thermal expansion.
Inventors
- 👤 Edward W. Tokarsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:30
CPC Classifications
H; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/0353; H05K1/0366; D; D21; D21H; D21H13/00; D21H13/10; D21H13/20; D21H13/26; H05K2201/00; H05K2201/02; H05K2201/0275; H05K2201/0278; H05K2201/0293; H05K2201/06; H05K2201/068; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12639; Y10T428/12646; Y10T428/31504; Y10T428/31511; Y10T428/31529; Y10T428/3154; Y10T428/31551; Y10T428/31562; Y10T428/31591; Y10T428/31678; Y10T428/31681; Y10T428/31692; Y10T428/31699; Y10T428/31725; Y10T428/3175; Y10T428/31971; Y10T428/31993
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
Process for preparing high density para-aramid paper for use in electrical circuit board laminates having low coefficient of thermal expansion comprising the steps of (1) preparing a 0.01 to 3 percent, by weight, aqueous slurry of para-aramid fibers made up of 0-50 volume percent para-aramid pulp and 50-100 volume percent para-aramid floc having lengths of 0.8 to 12.7 mm, (2) forming a sheet from the slurry using known papermaking methods, (3) drying the thusly formed sheet and (4) calendering the sheet in one or more steps between rigid rolls heated to 125° to 400° C. at a pressure of 1500 to 5000 lbs/inch (268 to 894 kg/cm) nip pressure.
Claim 2
Dependent Claim
109 words
Process for preparing high density para-aramid paper for use in electrical circuit board laminates having low coefficient of thermal expansion comprising the steps of (1) preparing a 0.01 to 3 percent, by weight, aqueous slurry of para-aramid fibers made up of 0-50 volume percent para-aramid pulp and 50-100 volume percent para-aramid floc having lengths of 0.8 to 12.7 mm, (2) forming a sheet from the slurry using known papermaking methods, (3) drying the thusly formed sheet and (4) calendering the sheet in one or more steps between rigid rolls heated to 125° to 400° C. at a pressure of 1500 to 5000 lbs/inch (268 to 894 kg/cm) nip pressure.
Claim 3
Dependent Claim
37 words
Process of claim 1 wherein preparing the slurry includes adding a binder which consists of 5 to 15 percent, by weight, based on the total solids content of the paper, of a polymeric binder of aramid fibrids.
Claim 4
Dependent Claim
56 words
Process of claim 1 wherein preparing the slurry includes adding a binder which consists of 5 to 15 percent, by weight, based on the total solids content of the paper, of a water dispersible polymeric binder selected from the group consisting of epoxy resins, phenolic resins, polyester resins, polyureas, polyurethanes, melamine formaldehyde resins and fluorocarbon resins.
Claim 5
Dependent Claim
12 words
Process of claim 2 wherein the aramid fibrids are poly(m-phenylene isophthalamide) fibrids.
Claim 6
Dependent Claim
59 words
Electrical circuit board substrate containing at least one layer of the para-aramid paper made by the process of claims 1, 2, or 3, having a volume percent total matrix binder of no more than 52 plus 0.13 times the volume percent para-aramid floc in the para-aramid fibers in the layers, but no less than 15 volume percent total binder.
Claim 7
Dependent Claim
15 words
The circuit board substrate of claim 5 having 50 to 80 volume percent para-aramid fibers.
Claim 8
Dependent Claim
36 words
The circuit board substrate of claims 5 or 6 having a volume percent total matrix binder of no more than 42 plus 0.13 times the volume percent para-aramid floc in the para-aramid fibers in the layers.
Claim 9
Dependent Claim
10 words
Process of claim 1 wherein the para-aramid is poly(p-phenylene terephthalamide).
Claim 10
Dependent Claim
10 words
Process of claim 2 wherein the para-aramid is poly(p-phenylene terephthalamide).
Claim 11
Dependent Claim
10 words
Process of claim 3 wherein the para-aramid is poly(p-phenylene terephthalamide).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-05 | 1991-04-06 | 1991-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-05 | 1995-04-06 | 1995-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-05 | 1999-04-06 | 1999-10-06 | $7700.00 | Window Closed / Lapsed |