Laminate made from epoxy resin, styrene-maleic anhydride copolymer and crosslinkers
View Patent ↗A composition useful as an impregnant for the making of laminates for printed wiring boards comprises a FR4 epoxy resin which is a bisphenol A epoxy resin advanced with tetrabromobisphenol A, a crosslinking agent of a strene-maleic anhydride copolymer and a co-crosslinking agent is an optionally brominated bisphenol A and/or an optionally brominated bisphenol A diglycidyl ether.
1. A laminate made from a resin composition comprising an FR4 epoxy resin, a copolymer of styrene and maleic anhydride (SMA) as a first cross-linking agent, and a co-cross-linking agent selected from the group consisting of bisphenol A (BPA), bisphenol A diglycidyl ether (BPADGE), and a mixture thereof, wherein the composition is free from an allyl network forming compound.
2. The laminate of claim 1 wherein the SMA has a molecular weight of from about 1400 to about 50,000, and an anhydride content of more than 15% by weight.
3. The laminate of claim 1 wherein the SMA is selected from one SMA or a mixture of SMAs having a styrene:maleic anhydride ratio of 1:1, 2:1, or 4:1, and a molecular weight from about 1400 to about 2,000.
4. The laminate according to claim 1 wherein a copolymer is used such as to give an equivalency ratio of anhydride and aromatic hydroxy groups:epoxy groups in the range of 50 to 150% by weight.
5. The laminate according to claim 1 wherein a copolymer is used such as to give an equivalency ratio of anhydride and aromatic hydroxy groups:epoxy groups in the range of 75 to 125% by weight.
6. The laminate according to claim 1 wherein a copolymer is used such as to give an equivalency ratio of anhydride and aromatic hydroxy groups:epoxy groups in the range of 90 to 110% by weight.
7. The laminate of claim 2 wherein the SMA has a molecular weight of from about 1400 to about 50,000, and an anhydride content of more than 15% by weight.
8. The laminate of claim 3 wherein the SMA has a molecular weight of from about 1400 to about 50,000, and an anhydride content of more than 15% by weight.
9. The laminate of claim 2 wherein the SMA is selected from one SMA or a mixture of SMA's having a styrene:maleic anhydride ratio of 1:1 to 4:1, and a molecular weight of from about 1400 to about 2,000.
10. The laminate of claim 3 wherein the SMA is selected from one SMA or a mixture of SMA's having a styrene:maleic anhydride ratio of 1:1 to 4:1, and a molecular weight of about 1400 to about 2,000.
11. The laminate of claim 1 wherein at least 10% by weight of BPA and at least 10% by weight BPADGE are employed.
12. The laminate of claim 1 wherein the SMA has a molecular weight of from about 1400 to about 50,000, and an anhydride content of more than 15% by weight.
13. The laminate of claim 1 wherein the SMA is selected from one SMA or a mixture of SMAs having a styrene:maleic anhydride ratio of 1:1, 2:1, or 4:1 and a molecular weight of from about 1400 to about 2,000.
14. The laminate of claim 1 wherein the resin is partially cured.
15. The laminate of claim 1 wherein the resin is fully cured.
16. A printed circuit board including one or more laminate layers wherein at lease one of the laminate layers is the laminate of claim 1 .
17. A printed circuit board including at least one laminate layer that is made from a resin composition comprising an FR4 epoxy resin, a copolymer of styrene and maleic anhydride (SMA) as a first cross-linking agent, and a second cross-linking agent selected from the group consisting of bisphenol A (BPA), bisphenol A diglycidyl ether (BPADGE), and a mixture thereof, wherein the composition is free from an allyl network forming compound.