US4477512A
Expired / Lapsed
US
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Flexibilized flame retardant B-staged epoxy resin prepregs and composite laminates made therefrom
Assignee: Isola Laminate Systems Corp
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Filing: 1983-04-29
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Granted: 1984-10-16
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Expires: 2003-04-29
Abstract
Abstract A prepreg useful as the core in flame resistant cooper clad, composite, printed circuit boards is made by impregnating a porous substrate with an impregnant containing: either a brominated epoxy or epoxy resin and reactive flame retarding additive containing bromine and phenolic hydroxyl groups (e.g., tetrabromobisphenol A), phenolic novolac oligomer as curing agent, unsaturated epoxidized oil, and optionally, a suitable catalyst; and then heating the impregnated substrate to the "B"-stage.
Inventors
- 👤 Wilbur R. Thomas
- 👤 Fred E. Hickman, III
- 👤 George J. Knight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:00
CPC Classifications
B; B32; B32B; B32B29/00; B32B29/002; B32B29/005; B32B15/00; B32B15/14; B32B27/00; B32B27/04; B32B29/02; C; C08; C08G; C08G59/00; C08G59/18; C08G59/20; C08G59/22; C08G59/30; C08G59/32; C08G59/38; C08G59/40; C08G59/62; C08G59/621; H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/40; H05; H05K; H05K1/00; H05K1/02; H05K1/03; H05K1/0313; H05K1/032; H05K1/0326; H05K1/0353; H05K1/036; B32B2260/00; B32B2260/02; B32B2260/028; B32B2260/04; B32B2260/046; B32B2305/00; B32B2305/02; B32B2305/026; B32B2307/00; B32B2307/30; B32B2307/306; B32B2307/3065; B32B2315/00; B32B2315/08; B32B2315/085; H05K1/0366; H05K2201/00; H05K2201/01; H05K2201/0104; H05K2201/012; H05K2201/02; H05K2201/0275; H05K2201/0284; H05K2201/0293; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31511; Y10T428/31515; Y10T428/31518; Y10T428/31522; Y10T428/31525; Y10T428/31529; Y10T428/31971; Y10T428/31989; Y10T442/00; Y10T442/20; Y10T442/2926; Y10T442/2992; Y10T442/30; Y10T442/3382; Y10T442/3415; Y10T442/3431; Y10T442/3439; Y10T442/3707; Y10T442/378; Y10T442/3813
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
89 words
A flexibilized, "B"-staged resin impregnated porous substrate, the impregnating resin comprising a mixture of: A. a brominated epoxy resin, or a mixture of a non-halogenated epoxy resin and a flame retarding reactive additive containing bromine and phenolic hydroxyl groups, B. an epoxidized oil, wherein the oil is naturally occurring unsaturated fatty oil, and C. phenolic novolac oligomer curing agent having an average of over 2.5 phenolic hydroxyl groups per oligomeric unit, where the porous substrate is selected from the group consisting of cellulosic paper and unwoven fibrous glass sheet.
Claim 2
Dependent Claim
89 words
A flexibilized, "B"-staged resin impregnated porous substrate, the impregnating resin comprising a mixture of: A. a brominated epoxy resin, or a mixture of a non-halogenated epoxy resin and a flame retarding reactive additive containing bromine and phenolic hydroxyl groups, B. an epoxidized oil, wherein the oil is naturally occurring unsaturated fatty oil, and C. phenolic novolac oligomer curing agent having an average of over 2.5 phenolic hydroxyl groups per oligomeric unit, where the porous substrate is selected from the group consisting of cellulosic paper and unwoven fibrous glass sheet.
Claim 3
Dependent Claim
28 words
The resin impregnated substrate of claim 1, where the combined total of phenolic hydroxyl equivalents is less than or essentially equal to the combined total of epoxy equivalents.
Claim 4
Dependent Claim
42 words
The resin impregnated substrate of claim 1, where the phenolic novolac oligomeric unit has an average of from 2.5 to 15 phenolic hydroxyl groups per oligomeric unit, and the ratio of epoxy equivalents:phenolic hydroxyl equivalents is from above 1:1 to about 1.6:1.
Claim 5
Dependent Claim
34 words
The resin impregnated substrate of claim 1, where the phenolic novolac oligomeric unit has an average of from 4 to 8 phenolic hydroxyl groups per oligomer and less than 1 weight percent free phenol.
Claim 6
Dependent Claim
45 words
The resin impregnated substrate of claim 1, where the phenolic novolac oligomer (IV) has the structural formula: ##STR8## where the average of n=0 to 2, and each R is selected from CH 2 , C 2 H 4 , and C 3 H 8 .
Claim 7
Dependent Claim
25 words
The resin impregnated substrate of claim 5, where the epoxy resin is a bisphenol A epoxy resin and the flame retarding additive is tetrabromobisphenol A.
Claim 8
Dependent Claim
21 words
The resin impregnated substrate of claim 6, where the epoxy resin is a mixture of bisphenol A epoxy and cycloaliphatic epoxy.
Claim 9
Dependent Claim
74 words
The resin impregnated substrate of claim 1 or claim 5, where the epoxidized oil constitutes at least about 5 percent, based on the total weight of resin solids of the impregnating resin, and functions as an internal flexibilizer during resin cure, said oil being selected from the group consisting of epoxidized corn oil, epoxidized cottonseed oil, epoxidized peanut oil, epoxidized menhaden oil, epoxidized linseed oil, epoxidized tung oil, epoxidized soybean oil, and mixtures thereof.
Claim 10
Dependent Claim
15 words
The resin impregnated substrate of claim 8, where the epoxidized oil is epoxidized soybean oil.
Claim 11
Dependent Claim
26 words
The resin impregnated substrate of claim 1 or claim 5, where the ratio of epoxy resin equivalents: epoxidized oil equivalents is from about 2 to 12:1.
Claim 12
Dependent Claim
116 words
A flexibilized, high pressure laminate comprising the bonded combination of: (1) outer surface layers of an epoxy impregnated woven glass fabric, and (2) a core layer comprising at least one resin impregnated porous sheet, the impregnating resin comprising a mixture of: A. a brominated epoxy resin, or a mixture of a non-halogenated epoxy resin and a flame retarding reactive additive containing bromine and phenolic hydroxyl groups, B. an epoxidized oil, wherein the oil is naturally occurring unsaturated fatty oil, and C. phenolic novolac oligomer curing agent having an average of over 2.5 phenolic hydroxyl groups per oligomeric unit, where the porous sheet is selected from the group consisting of cellulosic paper and unwoven fibrous glass sheet.
Claim 13
Dependent Claim
116 words
A flexibilized, high pressure laminate comprising the bonded combination of: (1) outer surface layers of an epoxy impregnated woven glass fabric, and (2) a core layer comprising at least one resin impregnated porous sheet, the impregnating resin comprising a mixture of: A. a brominated epoxy resin, or a mixture of a non-halogenated epoxy resin and a flame retarding reactive additive containing bromine and phenolic hydroxyl groups, B. an epoxidized oil, wherein the oil is naturally occurring unsaturated fatty oil, and C. phenolic novolac oligomer curing agent having an average of over 2.5 phenolic hydroxyl groups per oligomeric unit, where the porous sheet is selected from the group consisting of cellulosic paper and unwoven fibrous glass sheet.
Claim 14
Dependent Claim
20 words
The laminate of claim 11, where an electrically conductive metal layer is bonded to at least one of said surfaces.
Claim 15
Dependent Claim
11 words
The laminate of claim 12, where the metal layer is copper.
Claim 16
Dependent Claim
12 words
The laminate of claim 11, where the porous sheet is cellulosic paper.
Claim 17
Dependent Claim
43 words
The laminate of claim 11, where the phenolic novolac oligomer (IV) has the structural formula: ##STR9## where the average of n=0 to 2, and each R is selected from CH 2 , C 2 H 4 , and C 3 H 8 .
Claim 18
Dependent Claim
26 words
The laminate of claim 11, where the resin in the porous sheet was a mixture of (A) a non-halogenated epoxy resin and (B) tetrabrominated bisphenol A.
Claim 19
Dependent Claim
13 words
The laminate of claim 11, where the epoxidized oil is epoxidized soybean oil.
Claim 20
Dependent Claim
86 words
The laminate of claim 11, where the epoxidized oil constitutes at least about 5 percent, based on the total wieght of resin solids of the impregnating resin, the ratio of epoxy resin equivalents: epoxidized oil equivalents is from about 2 to 12:1, the epoxidized oil functions as an internal flexibilizer during resin cure, said oil being selected from the group consisting of epoxidized corn oil, epoxidized cottonseed oil, epoxidized peanut oil, epoxidized menhaden oil, epoxidized linseed oil, epoxidized tung oil, epoxidized soybean oil, and mixtures thereof.
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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) | 1987-10-16 | 1988-04-16 | 1988-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-16 | 1992-04-16 | 1992-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-16 | 1996-04-16 | 1996-10-16 | $7700.00 | Window Closed / Lapsed |