EPOXY RESIN COMPOSITION FOR COPPER CLAD LAMINATE, AND APPLICATION OF EPOXY RESIN COMPOSITION

Abstract

The present invention relates to an epoxy resin composition for a copper clad laminate, and an application of the epoxy resin composition. The epoxy resin composition may be used for the preparation of pre-pregs and copper clad laminates. By using brominated epoxy resin such as a low bromine epoxy resin and a high bromine epoxy resin as bromine sources and taking a phosphorus-containing phenanthrene-type compound as a phosphorus source, and adjusting the proportions of the brominated epoxy resins and the phosphorus-containing phenanthrene-type compound within the epoxy resin composition, the bromine content is controlled at 5-12%, the phosphorus content is controlled at 0.2-1.5%, and the flame retardancy achieves the level of UL94 V-0. Compared to pure bromine flame retardant copper clad laminates, the heat resistance is higher, and a higher CTI value is achieved. Compared to pure phosphorus flame retardant copper clad laminates, the moisture absorption is low, and the adhesion performance and process operability required for printed circuit substrates are provided. Compared to the use of a large amount of aluminum hydroxide in traditional high CTI sheet material, the present invention achieves CTI>600V using a small amount of aluminum hydroxide or without using aluminium hydroxide.

Claims

1.-10. (canceled)

11. An epoxy resin composition, characterized in comprising, based on the weight parts of organic solids, (A) from 50 to 100 parts by weight of a mixture of phosphorus-containing epoxy resin, bromine-containing epoxy resin and other epoxy resin, (B) from 1 to 50 parts by weight of a curing agent, (C) from 0.05 to 1.0 part by weight of a curing accelerator, wherein the bromine in the epoxy resin composition is in an amount of 5-12% of the weight sum of organic solids in the composition; the phosphorus in the epoxy resin composition is in an amount of 0.2-1.5% of the weight sum of organic solids in the composition.

12. The epoxy resin composition claimed in claim 11, wherein the bromine in the epoxy resin composition is in an amount of 5-10%, of the weight sum of organic solids in the composition; and wherein the phosphorus in the epoxy resin composition is in an amount of 0.5-1.5%, of the weight sum of organic solids in the composition.

13. The epoxy resin composition claimed in claim 11, wherein the bromine-containing epoxy resin comprises at least one member selected from the group consisting of low bromine epoxy resin, high bromine epoxy resin, brominated isocyanate-modified epoxy resin and brominated bisphenol-A novolac epoxy resin.

14. The epoxy resin composition claimed in claim 12, wherein the low bromine epoxy resin has a bromine content of 10%-25%; and the high bromine epoxy resin has a bromine of 40% or more.

15. The epoxy resin composition claimed in claim 11, wherein the phosphorus-containing epoxy resin is a phosphorus-containing phenanthrene compound.

16. The epoxy resin composition claimed in claim 11, wherein the phosphorus-containing epoxy resin comprises at least one member selected from the group consisting of the condensates of 9,10-dihydro-9-oxo-10-phosphaphenanthrene hydroquinone or 9,10-dihydro-9-oxo-10-phosphaphenanthrene naphthoquinone with bisphenol-A epoxy resin, o-cresol novolac epoxy resin, bisphenol-A novolac epoxy resin, phenol epoxy resin, dicyclopentadiene epoxy resin, MDI epoxy resin, bisphenol F epoxy resin and bisphenol S epoxy resin.

17. The epoxy resin composition claimed in claim 11, wherein said other epoxy resin is phosphorus- and bromine-free epoxy resin, and specifically is anyone selected from the group consisting of bisphenol-A epoxy resin, o-cresol novolac epoxy resin, bisphenol-A novolac epoxy resin, phenol epoxy resin, dicyclopentadiene epoxy resin, MDI epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, tetrafunctional epoxy resin, naphthalene epoxy resin and biphenyl epoxy resin, or a mixture of at least two selected therefrom.

18. The epoxy resin composition claimed in claim 11, wherein the curing agent comprises at least one member selected from the group consisting of phenolic resin, aromatic diamine-based curing agent, dicyandiamide, aliphatic amine, acid anhydride, active polyester and cyanate.

19. The epoxy resin composition claimed in claim 18, wherein the phenolic resin comprises at least one member selected from the group consisting of phenol novolac resin, bisphenol-A novolac resin, o-cresol novolac resin, triphenol novolac resin, naphthalene novolac resin, biphenyl novolac resin and dicyclopentadiene novolac resin.

20. The epoxy resin composition claimed in claim 18, wherein the aromatic diamine-based curing agent has the following chemical structural formula: ##STR00003## wherein X is selected from the group consisting of CH.sub.2, ##STR00004## R.sub.1, R.sub.3 and R.sub.4 are selected from the group consisting of H, CH.sub.3 and C.sub.2H.sub.5; R.sub.2 is selected from the group consisting of H, CH.sub.3 and C.sub.2H.sub.5.

21. The epoxy resin composition claimed in claim 11, wherein the mole number of the active hydrogen H in the curing agent and the mole number of the epoxy group E in the epoxy resin satisfy the formula H/E=0.8-1.2.

22. The epoxy resin composition claimed in claim 11, wherein the curing accelerator comprises at least one member selected from the group consisting of imidazole curing accelerator, organic phosphine curing accelerator and tertiary amine curing accelerator.

23. The epoxy resin composition claimed in claim 22, wherein the imidazole curing accelerator comprises at least one member selected from the group consisting of 2-methylimidazole, 2-methyl-4-ethylimidazole, 2-undecylimidazole, 2-phenylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole; the organic phosphine curing accelerator is tributylphosphine and/or triphenylphosphine; the tertiary amine curing accelerator is benzyl dimethyl amine.

24. The epoxy resin composition claimed in claim 11, wherein the epoxy resin composition further comprises a filler.

25. The epoxy resin composition claimed in claim 24, wherein the filler comprises at least one member selected from the group consisting of boehmite, aluminum hydroxide, barium sulfate, calcium fluoride, magnesium hydroxide, silica, glass powder, kaolin, talc powder, mica powder, aluminum oxide, zinc oxide, magnesium oxide, boron nitride, aluminum nitride and calcium carbonate; the filler has an average particle size of 0.3-20 m; the filler is in an amount of, based on the sum of organic solids of all components in the epoxy resin composition being 100 parts by weight, from 20 to 100 parts by weight.

26. The epoxy resin composition claimed in claim 11, wherein the epoxy resin composition further comprises a solvent.

27. The epoxy resin composition claimed in claim 26, wherein the solvent comprises at least one member from the group consisting of N,N-dimethyl-formamide, ethylene glycol ethyl ether, propylene glycol methyl ether, acetone, butanone, methanol, ethanol, benzene and toluene.

28. A prepreg prepared by using the epoxy resin composition claimed in claim 11, comprising a base material, and wherein the epoxy resin composition attached thereon after impregnation and drying.

29. A laminate comprising the prepreg claimed in claim 28.

30. A printed circuit board comprising the laminate claimed in claim 29.

Description

EMBODIMENTS

[0046] The technical solution of the present invention is further stated by the following specific embodiments, but is not limited to these embodiments,

[0047] Those skilled in the art shall know that said examples are only used for understanding the present invention, and shall not be deemed as specific limitations to the present invention.

Examples Process for Preparing CCLs

[0048] Epoxy resin, curing agent, filler and curing accelerator, together with organic solvent, were homogeneously mixed in a stirring and dispersing device. Said epoxy resin composition was pre-impregnated to non-woven or woven glass fiber cloth, and dried in a glue machine (120-180 C.) to prepare semi-cured prepregs for printed circuit boards.

[0049] Several sheets of prepreg above were stacked together. One side or both sides of the stacked sheets were laminated with copper foil, and then placed on a laminator at 120-200 C., hot-pressed into a form and prepared into a CCL for printed circuit board processing. Said copper foil can also be replaced with aluminum foil, silver foil or stainless steel foil.

[0050] As for CCLs prepared in said examples, performance tests were made for the glass transition temperature, CTI, flame retardancy, solder dipping resistance time, PCT water absorption, 5% thermal weight loss and drilling processability, and further described and stated in the following Examples 1-5 and Comparative Examples 1-7.

[0051] The components in the epoxy resin composition in Examples 1-5 and Comparative Examples 1-5 and contents thereof (parts by weight) are shown in Table 1, wherein the epoxy resin compositions in Table 1 are based on 100% of solid contents. The codes of each component and the corresponding component names are stated as follows.

(A) Epoxy resin
(A1) Brominated bisphenol-A epoxy resin: DER530A80, having an epoxy equivalent of 430 g/eq, from DOW Chemical;
(A2) brominated isocyanate-modified epoxy resin: DER592A80, having an epoxy equivalent of 360 g/eq, from DOW Chemical;
(A3) high bromine epoxy resin: EPICLON153-60M, having a bromine content of 48% and an epoxy equivalent of 380 g/eq, from DAINIPPON INK & CHEMICALS;
(A4) phosphorus-containing epoxy resin: GEBR521K70, having an epoxy equivalent of 540 g/eq, from Hongchang Resin;
(A5) tetrafunctional epoxy resin: 1031, having an epoxy equivalent of 210 g/eq, from Momentive;
(B) Curing agent
(B1) linear novolac resin: 2812, from Momentive;
(B2) aromatic diamine: 4,4-DDS, from Yinsheng Taiwan;

(C) Filler

(C1) Boehmite: Bengbu Xinyuan Quartz Material Limited Company;

[0052] (C2) Aluminum hydroxide: Albemarle Corporation;
(C3) Barium sulfate: Guizhou Redstar
(D) Curing accelerator: 2-E-4MI, Shikoku Chemicals;
(E) Organic solvent: butanone, from Dow Chemical.

[0053] The following methods are used to test the CCLs prepared in Examples 1-5 and Comparative Examples 1-7, and the test methods for each performance parameter are stated as follows. [0054] (A) Glass transition temperature (Tg): on the basis of the differential scanning calorimetry (DSC), tested according to the DSC method as stipulated under IPC-TM-650 2.4.25. [0055] (B) Comparative tracking index (CTI): tested according to the method as stipulated under GB/T 4207-84. [0056] (C) Solder dipping resistance time: impregnating a double-sided copper foil plate having a size of 100100 mm into a solder tank heated to 288 C., and recording the time from impregnation to delamination and popcorn of the plate. [0057] (D) PCT water absorption: pre-drying the sample, weighing and cooking in a pressure cooker for 4 hours, and observing the mass change rate. [0058] (E) 5% thermal weight loss: heating under the nitrogen atmosphere to 500 C. at a heating rate of 5 C./min, and recording the temperature at which the sample mass losses 5%. [0059] (F) Drilling processability: stacking two plates having a thickness of 1.6 mm together, continuously drilling 5000 holes with a 0.3 mm drill at a drilling speed of 110 krpm and a falling speed of 33 mm/s, observing the cutting edge wear of the drill per 1000 holes, and determining the drilling processability according to the wear conditions. [0060] (G) Flame retardancy: tested according to the method under UL 94.

[0061] The test results of the CCLs prepared in Examples 1-5 and Comparative Examples 1-7 are shown in Tables 2 and 3.

TABLE-US-00001 TABLE 1 Comp. Comp. Comp. Comp. Comp. Example Example Example Example Example Example Example Example Example Example Materials 1 2 3 4 5 1 2 3 4 5 A1 60 60 33 60 0 90 50 0 45 0 A2 0 0 0 0 60 0 0 0 0 0 A3 0 0 0 0 0 0 0 0 21 27 A4 7 25 67 25 25 0 0 90 7 42 A5 14 10 10 10 10 10 20 10 14 6 B1 17 20 20 20 20 20 19 20 17 10.2 B2 3 2.5 4 2.5 2.5 4 2 2 3 2.4 D 0.05 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.05 0.03 C1 30 30 30 0 30 30 30 30 30 18 C3 20 20 20 0 20 20 20 20 20 12 C2 10 10 10 0 10 10 10 10 10 6 E 40 40 40 20 40 40 40 40 35 18 Phosphorus 0.2% 0.64% 1.5% 0.64% 0.64% 0.00% 0.00% 2.21% 0.2% 1.7% content % Bromine 12.0% 10.2% 5.0% 10.2% 9% 14.5% 11.0% 0.0% 16.5% 12.0% content %

[0062] The preparation methods and material manufacturers in Comparative Examples 6 and 7 are listed as follows.

[0063] Comparative Example 6: 23 parts by weight of synthetic rubber (trade name Nipol 1072CGX, from ZEON), 25 parts by weight of brominated epoxy (trade name DER530A80, from DOW), 21 parts by weight of high bromine epoxy (trade name EPICLON 153-60M, from DAINIPPON INK & CHEMICALS), 25 parts by weight of biphenyl epoxy (trade name NC3000H, from Nippon Kayaku), 0.2 part by weight of 2E4MI (from Shikoku Chemicals), 10.1 parts by weight of aromatic diamine: 4,4-DDS (from Yinsheng Taiwan), 20 parts by weight of phenoxyphosphazene (SPB-100, having a phosphorus content of 13.4%, from Albemarle Corporation), 15 parts by weight of aluminum hydroxide (from Albemarle Corporation), 31 parts by weight of boehmite (from to Bengbu Xinyuan Quartz Material Limited Company), 8 parts by weight of barium sulfate(Guizhou Redstar), solvent MEK to adjust the solid content to 66%.

[0064] Calculation: having a bromine content of 12.0% and a phosphorus content of 0.2%; the filler proportion and ratio were the same as those in Example 1.

[0065] Comparative Example 7: 33 parts by weight of nitrile rubber-modified epoxy (SC-024, from SHIN-A), 67 parts by weight of brominated epoxy resin (DEBR530A80, from DOW), 3 parts by weight of dicyandiamide, 0.02 part by weight of 2-methylimidazole, 6 parts by weight of tetrabromobisphenol A, 31 parts by weight of phosphorus-containing phenolic aldehyde (LC950, from SHIN-A), 17 parts by weight of aluminum hydroxide (from Albemarle Corporation), 34 parts by weight of boehmite (from Bengbu Xinyuan Quartz Material Limited Company), 9 parts by weight of barium sulfate (from Guizhou Redstar), solvent MEK to adjust the solid content to 66%.

[0066] Calculation: having a bromine content of 12.0% and a phosphorus content of 0.2%; the filler proportion and ratio were the same as those in Example 1.

TABLE-US-00002 TABLE 2 Example Example Example Example Example Comp. Comp. Test items 1 2 3 4 5 Example 1 Example 2 Tg (DSC) ( C.) 142 141 144 140 149 133 140 CTI (V) 600 600 600 175 600 500 600 Solder dipping >600 s >600 s >600 s >600 s >600 s <400 s >600 s resistance time PCT water 0.19 0.21 0.25 0.22 0.24 0.20 0.21 absorption % Td 5% 360 362 366 360 358 350 361 Flammability V-0 V-0 V-0 V-0 V-0 V-0 V-1 Drilling Good Good Good Good Good Good Good

TABLE-US-00003 TABLE 3 Comp. Comp. Comp. Comp. Comp. Example Example Example Example Example Test items 3 4 5 6 7 Tg (DSC) ( C.) 134 141 139 112 131 CTI (V) 600 300 V 600 V 525 V 550 V Solder dipping >600 s <400 s <300 s <300 s <300 s resistance time PCT water 0.35 0.22 0.33 0.55 0.58 absorption % Td 5% 367 352 359 348 344 Flammability V-0 V-0 V-0 V-0 V-0 Drilling General General General Good Good

[0067] According to Tables 1-3, the followings can be seen.

(1) According to Examples 1-5, it can be seen that the epoxy resin compositions in Examples 1-5 all could achieve the flame retardancy of UL 94 V-0 level, and have a solder dipping resistance time of greater than 600 s and a better drilling processability,
(2) According to Examples 1-5, it could be seen that the epoxy resin compositions in Examples 1-3 all had a Comparative Tracking Index (CTI) of 600V, while the epoxy resin composition in Example 4 had a Comparative Tracking Index (CTI) of only 175V, which showed that the addition of a suitable amount of filler into the epoxy resin composition could make the substrate have a high CTI.
(3) As compared to Comparative Example 3, the POT water absorptions in Examples 1-5 were better than that in Comparative Example 3. Since only phosphorus-containing epoxy resin was used in Comparative Example 3, and the phosphorus content was as high as 2.21%, the moisture absorption thereof was increased. In Examples 1-5, phosphorus-containing epoxy resin and bromine-containing epoxy resin were both used, and low moisture absorption could be achieved when the phosphorus content was only 0.2%-1.5%, which showed that the substrates could have a low water absorption when phosphorus-containing epoxy resin and bromine-containing epoxy resin were used in combination.
(4) As compared to Comparative Example 2, Examples 2-5 disclosed that phosphorus and bromine were used synergistically for flame retardancy, and only less than 11% of bromine was needed to achieve the UL94 V-0 level. Comparative Example 2 disclosed only introducing bromine for flame retardancy. Although the bromine content reached 11%, it could not achieve the UL94 V-0 level yet.
(5) As compared to Comparative Example 1, Examples 1-5 disclosed that, since phosphorus and bromine were used synergistically for flame retardancy, only 12% or less of bromine was needed to achieve the UL94 V-0 level. Thus, Examples 1-5 had better chemical heat resistance than Comparative Example 1, i.e. 5% thermal weight loss temperature being 10 C. higher than that in Comparative Example 1, and longer solder dipping resistance time.
(6) Comparative Examples 4 and 5 respectively disclosed the circumstances in which the bromine content and phosphorus content were not within the range of the present invention. It could be seen that, when the bromine content was 16.5%, Td and soldering dipper resistance time were obviously lower than those in Example 1, and CTI could not reach 600V, although the flame retardancy could be achieved. When the phosphorus content was 1.7%, the materials were also flame retardant although the CTI reached 600V. However, the soldering dipping resistance time was reduced to 300 s or less, and the PCT water absorption reached higher than 0.3%.
(7) Comparative Examples 6 and 7 respectively disclosed the resin compositions in CN 101808466A and CN 101892027A could not reach a CTI of 600V when having the same bromine content, phosphorus content and filler system as the present invention. Moreover, the water absorption was obviously higher than that of the present invention, and the soldering dipping resistance time could not reach 300 s. The present invention, however, showed a better thermal shock resistance. By comparing the present invention with Comparative Example 6, it can be found that the reactive phosphorus- and bromine-introduction way can have no effect on the glass transition temperature of the materials. Although phosphorus-containing phenolic aldehyde in Comparative Example 7 can participate in the reaction, the reactivity itself is poor, and it is hard to completely graft to the polymer backbone. Thus it will affect the Tg of the plates.

[0068] In conclusion, the epoxy resin composition of the present invention has a greatly increased heat resistance as compared to pure bromine flame retardant system, and has a CTI of 600V or higher after the filler such as boehmite is added. As compared to pure phosphorus flame retardant system, the epoxy resin composition has a lower water absorption, a better drilling processability and a better flame retardancy. The prepregs and CCLs prepared from said epoxy resin composition have excellent CTI property, so as to significantly improve the adaptability of PCBs in harsh environments. Meanwhile, relatively higher thermal resistance and longer solder dipping resistance time make the epoxy resin composition be suitable for the needs of lead-free soldering. Moreover, the present invention can further reduce the dependence of flame retardancy on bromine, so as to be more environmentally friendly.

[0069] The applicant claims that the present invention describes the detailed process of the present invention, but the present invention is not limited to the detailed process of the present invention. That is to say, it does not mean that the present invention shall be carried out with respect to the above-described detailed process of the present invention. Those skilled in the art shall know that any improvements to the present invention, equivalent replacements of the raw materials of the present invention, additions of auxiliary, selections of any specific ways all fall within the protection scope and disclosure scope of the present invention.