Laminate comprising non-woven fibrous backing

• US 3,878,316 A
• Filed: 01/16/1973
• Issued: 04/15/1975
• Est. Priority Date: 07/08/1970
• Status: Expired due to Term

• Current Assignee: Gaylord L. Groff
• Original Assignee: Gaylord L. Groff
• Inventors: Groff, Gaylord L.
• Primary Examiner(s): Lesmes, George F.
• Assistant Examiner(s): Bell, James J.
• Application Number:
  US05/324,219
• Time in Patent Office: 819 Days
• Field of Search: 161/151,169,170,214,227,231,150,146,DIG.7 174/68.5 57/14BY 117/138.8F,138.8N
• US Class Current: 174/258
• CPC Class Codes: D04H 1/4342 Aromatic polyamides
• CPC Class Codes: D04H 1/435 Polyesters
• CPC Class Codes: D04H 1/43835 Mixed fibres, e.g. at least two chemically different fibres or fibre blends
• CPC Class Codes: H05K 1/0366 reinforced, e.g. by fibres, fabrics H05K1/036 takes precedence
• CPC Class Codes: H05K 2201/0145 Polyester, e.g. polyethylene terephthalate [PET], polyethylene naphthalate [PEN]
• CPC Class Codes: H05K 2201/0278 Polymeric fibers
• CPC Class Codes: H05K 2201/0284 Paper, e.g. as reinforcement
• CPC Class Codes: H05K 2201/0293 Non-woven fibrous reinforcement
• CPC Class Codes: Y10T 442/692 Containing at least two chemically different strand or fiber materials

Abstract

The disclosed laminate is suitable for use in the art of printed circuitry and comprises an electrically conductive layer and a nonwoven backing layer. The nonwoven backing has unusual dimensional stability under a wide variety of conditions and preferably comprises a blend of at least 15 wt. % polyester staple and at least 10 wt. % aromatic polyamide staple. This blend is impregnated with a thermosettable resin.

Claims

1. AN ARTICLE COMPRISING AN ELECTRICALLY CONDUCTIVE METAL FILM LAYER IN ADHERENT CONTACT WITH A MAJOR SURFACE OF A SHEETLIKE NONWOVEN WEB IMPREGNATED WITH AN ELECTRICALLY INSULATIVE, MOISTURE-INSENSITIVE THERMOSET RESIN, SAID SHEET-LIKE NONWOVEN WEB BEING FORMED FROM A FIBER BLEND COMPRISING AT LEAST 15 WEIGHT % DISCONTINUOUS SYNTHETIC HEAT SOFTENABLE FIBERS, SAID SYNTHETIC HEAT-SOFTENABLE FIBERS BEING AT LEAST PARTIALLY HEAT SOFTENABLE AT TEMPERATURES BELOW 200*C., AND, IN INTIMATE ADMIXTURE WITH SAID HEAT SOFTENABLE FIBERS, AT LEAST 10 BUT NO MORE THAN ABOUT 75 WEIGHT % DISCONTINUOUS SYNTHETIC HEAT RESISTANT FIBERS, SAID HEAT RESISTANT FIBERS BEING RESISTANT TO TEMPERATURES IN EXCESS OF 250*C.

2. An article according to claim 1 wherein said conductive layer comprises copper.

3. An article according to claim 1 wherein said discontinuous synthetic heat softenable fibers of said fiber blend are undrawn polyester staple fibers and said synthetic heat resistant fibers of said fiber blend are aromatic polyamide staple fibers.

4. An article according to claim 3 wherein said fiber blend contains 25 - 65 weight percent of said aromatic polyamide staple fibers.

5. An article according to claim 1 wherein said electrically conductive layer is smaller in area than said major surface of said sheet-like nonwoven web.

6. AN ARTICLE ACCORDING TO CLAIM 1 FURTHER COMPRISING ELECTRICAL COMPONENTS ELECTRICALLY CONNECTED TO SAID ELECTRICALLY CONDUCTIVE LAYER.

7. An article according to claim 1 wherein said sheet-like nonwoven web is formed from a fiber blend comprising drawn and undrawn polyester staple fiber and heat resistant aromatic polyamide staple fiber, said fiber blend containing up to 60 weight percent drawn polyester staple fiber, the amount of said drawn polyester staple fiber being no more than twice the amount of said undrawn polyester staple fiber.

8. An article comprising an electrically conductive metal film layer bonded to and at least partially covering a backing, said backing being less than 20 mils in thickness and being at least as flexible as a 10-mil thick biaxially oriented poly(ethylene terephthalate) film, said backing comprising a sheet-like nonwoven web impregnated with an electrically insulative, moistureinsensitive thermoset resin, said sheet-like nonwoven web, prior to impregnation, having a Gurley value, ASTM Test D 726, Method A, of less than 100 seconds per 100 cc of air per 5 mils of thickness, said sheet-like nonwoven web being formed from a fiber blend comprising:

0 - 60 weight percent drawn polyester staple fiber;

15 - 60 weight percent undrawn polyester staple fiber, and 10 - 75 weight percent aromatic polyamide staple fiber, said sheet-like nonwoven web being autogenously bonded.

9. An article according to claim 8 wherein the amount of said drawn polyester staple fiber is no greater than twice the amount of said undrawn polyester staple fiber.

10. An article according to claim 8 wherein said electrically conductive layer is electrically connected to electrical components.

11. An article comprising an electrically conductive metal film layer bonded to and at least partially covering a backing, said electrically conDuctive layer having a coefficient of linear thermal expansion less than 30 X 10 6 for a 1* C. rise in temperature, at least within the temperature range of 30* - 120* C., said backing comprising a sheet-like nonwoven web impregnated with an electrically insulative, moisture insensitive resin, said sheet-like nonwoven web, after being impregnated with said resin, having a coefficient of linear thermal expansion less than 30 X 10 6 for a 1* C. rise in temperature, at least within the temperature range of 30* - 120* C., said sheet-like nonwoven web being formed from a fiber blend comprising at least 15 weight % discontinuous synthetic heat softenable fibers, said synthetic heat softenable fibers being at least partially heat softenable at temperatures below 200* C., and, in intimate admixture with said heat softenable fibers, at least 10 but no more than 75 weight % discontinuous synthetic heat resistant fibers, said heat resistant fibers being at least resistant to temperatures up to 250* C.

12. An article according to claim 11 wherein the temperature range for the determination of said coefficient of linear thermal expansion of said electrically conductive layer and said sheet-like nonwoven web impregnated with said resin is 30* - 160* C., in which range said coefficient is less than 30 X 10 6 per *C.

13. An article according to claim 1 wherein conductive layers are in adherent contact with two major opposed surfaces of said impregnated, sheet-like nonwoven web.