Novel halogen free epoxy resin for high performance electronic applications

1. Novel halogen free epoxy resin for high performance electronic applications P.K.Dubey, Dr. Hitesh Soni*, Dr. M.Soni, Ms. Thipa Thai Organics Chemicals Co., Ltd. (Epoxy Division)Map Ta Phut-Rayong (Thailand) TRFA Annual meeting, Florida, USA

2. Introduction: PWB, flip chip encapsulation, surface mounting adhesives, conformal and die coatings are major applications requiring FR epoxy resin Demand of halogen free fire retardant material due to environmental issues Lead free soldering calling for high heat resistance Miniaturization of electronic components requiring high thermal stability TRFA Annual meeting, Florida, USA

3. Conventional FR epoxy resins Bromine containing Standard for many years and have environmental and thermal stability issue Filler containing Capable to achieve V-0 rating Problem of high viscosity, aggregation of filler and micro structural defects in cured resin Red phosphorous Suitable to achieve V-0 rating but have issue of pigmentation & handling Phosphorous additives Effective fire-retardants. Problem of high water affinity, risk of p-o-p or c-o-p bonds under humid condition along with low thermal stability TRFA Annual meeting, Florida, USA

4. R-H + •X R• + HX HX + •OH H2O + •X Px H3POX -H2O H3POX + CH2–CH2 –H3PO4 + C Mechanism of various flame retardant action 1. Halogen based flame retardant 2. Filler based flame retandant Al(OH)3xH20 Al2O3 + H2O 3. Phosphorus based flame retardant TRFA Annual meeting, Florida, USA

5. Present work Reactive phosphorous compound (DOPO) selected for study as fire-retardant Multifunctional EOCN and EBPN resins synthesized and suitably reacted with DOPO Phenolic compounds based on phenol Novolac, bis-phenol Novolac, O-cresol Novolac, and tris-phenols are selected as hardener. 2MI and TPP are used as catalyst All sets of combinations studied for thermal, mechanical, and electrical properties. TRFA Annual meeting, Florida, USA

6. Epoxy Resin: YDBN 602 and YDBN 602P TRFA Annual meeting, Florida, USA

7. Epoxy resin TOCN 4030 and TOCN 4030P TRFA Annual meeting, Florida, USA

8. Phenolic Hardeners: Phenol Novolac-PN O-Cresol Novolac- OCN BPA Novolac- BPN Tris- Phenol- TP TRFA Annual meeting, Florida, USA

9. Catalyst 2- Methyl Imidazole- 2MI Triphenyl Phosphine- TPP TRFA Annual meeting, Florida, USA

10. Reaction Mechanism of 2-MI with epoxy group Source: Farkas, A., Strohem, P.F., J.Appl. Polym. Sci., 1968, 12, p159 TRFA Annual meeting, Florida, USA

11. mechanism of reaction between epoxy and phenol using TPP as catalyst Romanchick, W.A., Sohn, J.E., and Geibel, J.F., ACS Symposium Series 221-Epoxy Resin Chemistry II ( Ed: R.S.Bauer) American Chemical Society, Washington, D.C. 1982, p-85 TRFA Annual meeting, Florida, USA

12. Basic Properties of Epoxy resins TRFA Annual meeting, Florida, USA

13. Typical properties Epoxy resins • Physical properties are comparable TRFA Annual meeting, Florida, USA

14. Typical properties Epoxy resins • Melt viscosity is low in case of YDBN resins in-spite of high Mw/Mn ratio. • YDBN resins has lower softening point TRFA Annual meeting, Florida, USA

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17. Curing Behavior of Epoxy resins with Phenolic hardeners TRFA Annual meeting, Florida, USA

18. OCN is fastest reactive phenolic hardener TRFA Annual meeting, Florida, USA

19. YDBN 602 is more reactive because of better structural symmetry and low melt viscosity TRFA Annual meeting, Florida, USA

20. 2MI is more reactive compared to TPP because of alkoxide ion formation and more basicity of the 2MI catalyst TRFA Annual meeting, Florida, USA

21. Modified resins are lower in reactivity due to the presence of acidic Phosphorus compounds. TRFA Annual meeting, Florida, USA

22. Possible reaction of Phosphorus Resin with Catalyst polymerization Ring cleavage TRFA Annual meeting, Florida, USA

23. Phenolic reactivity trend- OCN>PN>TP>BPN TRFA Annual meeting, Florida, USA

24. Thermal Property TRFA Annual meeting, Florida, USA

25. Sample cured 175oC/6hrs • Concentration of catalyst effect reactivity not the final crosslink structure • 2-MI system gives higher Tg than TPP system TRFA Annual meeting, Florida, USA

26. 6 hrs at 175oC is adequate curing schedule for full crosslinking • YDBN system shows higher Tg compared to TOCN system TRFA Annual meeting, Florida, USA

27. Sample cured 175oC/6hrs • TP shows highest Tg(230-235oC) • YDBN systems shows better Tg compared to TOCN system in all cases. • Modified resins shows lower Tg-due to high EEW and polarity. • Modified resins with 2MI catalyst shows Tg in range of 155-185oC depending on curing agent TRFA Annual meeting, Florida, USA

28. Flammability And Thermal Degradation TRFA Annual meeting, Florida, USA

29. Effect of Phosphorus content on flammability • 1.5% Phosphorus is adequate to get flammability rating V-O • YDBN resins shows better flammability rating compared to TOCN • TPP catalyst shows better flammability rating than 2MI TRFA Annual meeting, Florida, USA

30. YDBN resins shows better thermal degradation stability • P- resins shows initial loss at low temperature but Tmax is higher than unmodified resins • TPP cured system shows better overall degradation stability TRFA Annual meeting, Florida, USA

31. YDBN 602 char yield is higher than TOCN 4030- better flammability. • Incorporation of phosphorus increases char yield dramatically. • TPP cured system shows better char yield than 2MI TRFA Annual meeting, Florida, USA

32. Mechanical Property TRFA Annual meeting, Florida, USA

33. Electrical property TRFA Annual meeting, Florida, USA

34. Conclusion: • Halogen free YDBN-P and TOCN-P resins could be material of choice where high glass transition temperature (170-190oC) or flammability is desired for electrical and electronics applications. • YDBN series of resins were found comparable to TOCN resins in terms of mechanical, electrical and thermal properties with distinct advantage of lower melt viscosity which could be advantageous for better wetting or lower coating thickness requirements. • Curing agents could be selected depending on process/ performance requirements. TP has exhibited higher Tg with low melt viscosity where as low functionality PN could be used for moderate Tg requirement. • 2MI as catalyst lead to higher Tg of cured matrix compared to TPP. TRFA Annual meeting, Florida, USA

35. Acknowledgement: • Sincerely thanks • Management of TOCC • All Colleagues Somsak, Satid, Thithikan and Thaniya • Mr. Wutti of Mettler Toledo, Thailand TRFA Annual meeting, Florida, USA

36. Thank you TRFA Annual meeting, Florida, USA

37. Any Question? TRFA Annual meeting, Florida, USA