THERMOSETTING RESIN COMPOSITION, PREPREG CONTAINING SAME, LAMINATED BOARD, AND PRINTED CIRCUIT BOARD

Abstract

A thermosetting resin composition. The composition comprises thermosetting resin, a cross-linking agent, accelerator, and a porogen. The porogen is a porogen capable of being dissolved in an organic solvent. The organic solvent is an organic solvent capable of dissolving the thermosetting resin. A mode of directly adding the dissolvable porogen to a resin system is used, tiny pores that are uniform in pore diameter can be evenly distributed in resin matrix by means of a simple process at low cost, and the high-performance composition having a low dielectric constant and low dielectric loss is obtained; the method has good applicability to a great number of resin systems; because the pore size in the system reaches a nanometer grade, performance of the final system, such as mechanical strength, thermal performance and water absorption rate, is not sacrificed.

Claims

1-12. (canceled)

13. A thermosetting resin composition, comprising a thermosetting resin, a crosslinking agent, an accelerator and a porogen, wherein the porogen is soluble in an organic solvent.

14. The composition claimed in claim 13, wherein the organic solvent is any one selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl acetate, dichloromethane, cyclohexanone, butanone, acetone, ethanol, toluene, xylene, and a mixture of at least two selected therefrom.

15. The composition claimed in claim 13, wherein the porogen is any one selected from the group consisting of azo compound, nitroso compound, dicarbonate compound, azide compound, hydrazine compound, and a combination of at least two selected therefrom.

16. The composition claimed in claim 15, wherein the nitroso compound is in a powder shape having an average particle size of 0.1-50 m.

17. The composition claimed in claim 13, wherein the porogen is present in an amount of 10 wt. % or less in the thermosetting resin composition.

18. The composition claimed in claim 13, wherein the porogen can release gas at 100-190 C.

19. The composition claimed in claim 13, wherein the porogen is nitroso compound and/or azide compound.

20. The composition claimed in claim 13, wherein the porogen is sulfonyl azide compound.

21. The composition claimed in claim 13, wherein the composition comprises the following components, in percent by weight, from 50 to 90 wt. % of a thermosetting resin, less than 30 wt. % of a crosslinking agent, from 0.1 to 10 wt. % of an accelerator and less than 10 wt. % of a porogen, wherein the sum of the weight percents of all components in the composition is 100 wt. %.

22. The composition claimed in claim 13, wherein the composition comprises the following components, in percent by weight, from 50 to 70 wt. % of a thermosetting resin, from 10 to 30 wt. % of a crosslinking agent, from 3 to 10 wt. % of an accelerator and from 3 to 10 wt. % of a porogen, wherein the sum of the weight percents of all components in the composition is 100 wt. %.

23. The composition claimed in claim 13, wherein the thermosetting resin is any one selected from the group consisting of polymers crosslinkable to form a network structure, or a combination of at least two selected therefrom.

24. The composition claimed in claim 13, wherein the thermosetting resin is any one selected from the group consisting of epoxy resin, phenolic resin, cyanate resin, polyamide resin, polyimide resin, polyether resin, polyester resin, hydrocarbon resin, benzoxazine resin, silicone resins, and a combination of at least two selected therefrom.

25. A resin glue, wherein the resin glue is obtained by dispersing the thermosetting resin composition in claim 13 in a solvent.

26. The resin glue claimed in claim 25, wherein the solvent is any one selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, propylene glycol methyl ether, propylene glycol methyl ether acetate, ethyl acetate, dichloromethane, cyclohexanone, butanone, acetone, ethanol, toluene, xylene, and a combination of at least two selected therefrom.

27. A prepreg, wherein the prepreg comprises a reinforcing material and the thermosetting resin composition according to claim 13 attached thereon after impregnating and drying.

28. A laminate comprising at least one prepreg of claim 27.

29. A printed circuit board comprising at least one laminate of claim 28.

Description

Experiment Group A (Table 1)

EXAMPLES 1-3

[0046] 100 parts by weight of epoxy resin DER530, 3 parts by weight of dicyandiamide, 0.05 parts by weight of 2-methylimidazole, 4-methylbenzenesulfonyl azide (having 1, 5, 10 parts by weight respectively) were dissolved in an organic solvent and mechanically stirred, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Comparison Examples 1-2

[0047] The embodiments are the same as Example 1, and their difference lies in that the porogen was in an amount of 0 part in Comparison Example 1, and 12 parts in Comparison Example 2.

Experiment Group B (Table 2)

Example 4

[0048] 100 parts by weight of epoxy resin DER530, 3 parts by weight of dicyandiamide, 0.05 parts by weight of 2-methylimidazole and 5 parts by weight of N,N-dinitrosopentamethylene tetraamine were dissolved in an organic solvent and mechanically stirred, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Comparison Examples 3-4

[0049] The mass ratios and feeding modes of each component are the same as those in Example 4, and their difference lies in that the porogen was azodicarbonamide in Comparison Example 3, and ammonium bicarbonate in Comparison Example 4.

Experiment Group C (Table 3)

Example 5

[0050] 100 parts by weight of epoxy resin DER530, 24 parts by weight of phenolic resin TD2090, 0.05 parts by weight of 2-methylimidazole and 5 parts by weight of a soluble porogen (4-methylbenzenesulfonyl azide) were dissolved in an organic solvent and mechanically stirred and emulsified, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Example 6

[0051] 20 parts by weight of phenol novolac cyanate PT30, 40 parts by weight of o-cresol novolac epoxy resin N695, 20 parts by weight of brominated styrene and a proper amount of catalyst zinc octoate, 2-phenylimidazole, and 5 parts by weight of a soluble porogen (4-methylbenzenesulfonyl azide) were dissolved in an organic solvent and mechanically stirred and emulsified, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Example 7

[0052] 70 parts by weight of vinyl-based thermosetting polyphenylene ether MX9000 dissolved in toluene, 5 parts by weight of bifunctional maleimide from KI Chemical dissolved in N,N-dimethylformamide, 25 parts by weight of butadiene-styrene copolymer R100, 3 parts by weight of a curing initiator DCP, and 5 parts by weight of a soluble porogen (4-methylbenzenesulfonyl azide) were dissolved in an organic solvent and mechanically stirred and emulsified, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Example 8

[0053] 30 parts by weight of dicyclopentadiene epoxy HP-7200H, 60 parts by weight of benzoxazine resin D125, 5 parts by weight of linear novolac resin EPONOL 6635M65, 5 parts by weight of dicyandiamide, and 5 parts by weight of a soluble porogen (4-methylbenzenesulfonyl azide) were dissolved in an organic solvent and mechanically stirred and emulsified, formulated into 65 wt. % of a glue. Then glass fiber cloth was impregnated therewith, heated and dried to form a prepreg. Copper foils were placed on both sides of the prepreg, pressed and heated to produce a copper clad laminate.

Comparison Examples 5-8

[0054] The embodiments therein correspond to those in Examples 5-8 respectively, and their difference lies in that the formulation systems in Comparison Examples 5-8 contain no soluble porogen.

TABLE-US-00001 TABLE 1 Effects of the amount of the porogen Formulation Comp. Types and Examples Examples amounts No. of the porogen 1 2 3 1 2 4-methylbenzenesulfonyl azide 1 5 10 12 Material Properties Dielectric constant/dielectric 4.5/0.011 4.2/0.008 4.1/0.008 4.7/0.011 4.1/0.075 loss (1 MHz) Water absorption/% 0.20 0.20 0.25 0.20 0.45 Glass transition temperature 135 135 134 135 128 (Tg)/ C. Bending strength/MPa 600/500 640/550 620/520 600/500 520/400 (warp-wise/weft-wise) Bending modulus/GPa 25/24 27/26 25/24 25/24 20/18 (warp-wise/weft-wise) Tensile strength/MPa 250/240 250/240 240/240 250/240 200/190 (warp-wise/weft-wise) Peeling strength/N .Math. mm.sup.1 1.60 1.62 1.59 1.60 1.47

TABLE-US-00002 TABLE 2 Effects of the type of the porogen Comp. Formulation Examples Examples Types and amounts No. of the porogen 2 4 3 4 4-methylbenzenesulfonyl azide 5 N,N-dinitrosopentamethylene 5 tetraamine Azodicarbonamide 5 Ammonium bicarbonate 5 Material Properties Dielectric constant/dielectric 4.2/0.008 4.4/0.010 4.6/0.011 4.7/0.011 loss (1 MHz) Water absorption/% 0.20 0.23 0.25 0.22 Glass transition temperature 135 131 122 130 (Tg)/ C. Bending strength/MPa 640/550 590/510 550/460 590/500 (warp-wise/weft-wise) Bending modulus/GPa 27/26 25/24 22/23 25/24 (warp-wise/weft-wise) Tensile strength/MPa 250/240 230/230 180/180 250/240 (warp-wise/weft-wise) Peeling strength/N .Math. mm.sup.1 1.60 1.59 1.42 1.60

TABLE-US-00003 TABLE 3 Effects of the type of the thermosetting resin system Formulation Examples Comp. Examples Types and No. amounts of the porogen 5 6 7 8 5 6 7 8 4-methylbenzenesulfonyl 5 5 5 5 azide Material Properties Dielectric 4.4/ 4.1/ 3.7/ 3.9/ 4.9/ 4.4/ 3.90/ 4.2/ constant/dielectric loss 0.012 0.008 0.006 0.010 0.013 0.008 0.006 0.010 (1 MHz) Water absorption/% 0.25 0.48 0.05 0.08 0.25 0.45 0.04 0.08 Glass transition 156 219 210 167 157 219 212 167 temperature (Tg)/ C. Bending strength/MPa 550/ 380/ 550/ 500/ 330/ 520/ (warp-wise/weft-wise) 500 350 550 450 330 530 Bending modulus/GPa 24/ 19/ 22/ 16/ (warp-wise/weft-wise) 24 17 21 17 Tensile strength/MPa 260/ 200/ 260/ 210/ (warp-wise/weft-wise) 260 190 260 210 Peeling strength/N .Math. mm.sup.1 1.55 1.00 1.40 1.41 1.55 1.02 1.45 1.43

[0055] Those skilled in the art shall know that the above examples are merely used for understanding the present invention, rather than specific limitations to the present invention.

[0056] According to the performance test results in Table 1, it can be seen that, since homogeneously-distributed micropores and nanopores are formed inside the system in the examples in which the soluble porogen is added, the dielectric constant thereof is reduced apparently. Moreover, the formed micropores can prevent the cracks from expanding when the sheets are pressed, thereby resulting in a certain increase in the bending strength, bending modulus and the like. However, the tensile strength, peeling strength and glass transition temperature are not affected basically. When the soluble porogen is added in an amount of 5 wt. %, such system has a lower dielectric constant and loss, as well as best bending strength. Along with further increase of the amount of the porogen (Comparison Example 2), the decrease of the dielectric loss of the sheet is not obvious. However, the glass transition temperature and mechanical performance are reduced greatly. Meanwhile, the bubbles produced during the decomposition thereof greatly reduce the peeling strength of the sheets. Thus the amount of the porogen is preferably 1-10 wt. %.

[0057] According to the performance test results in Table 2, it can be seen that Example 2 has the best overall performance. This is mainly due to the fact that the decomposition temperature of 4-methylbenzenesulfonyl azide is in the production temperature range of common copper clad laminates, and it is liquid at room temperature and can form a homogeneous system with epoxy resin; and the porogen can be dispersed into the entire formulation system in a molecular grade. The pore size reaches the nanometer level and has entire plate uniformity.

[0058] The porogen used in Example 5 is N,N-dinitrosopentamethylene tetraamine, which has a decomposition temperature higher than 170 C. and can be dissolved in a solvent such as acetone at room temperature, and can also be well dispersed throughout the entire epoxy formulation system, and has better pore-forming effect. The porogen used in Comparison Example 3 is azodicarbonamide, which has a decomposition temperature higher than 160 C., but is insoluble in common organic solvents, so that it cannot be well dispersed in the entire formulation system. By the experimental investigation, it can be found that it has an uneven pore-forming distribution, a pore size of more than 20 microns, as well as greatly reduced glass transition temperature, peeling strength and mechanical strength of the sheets, so that it cannot meet the reliability of copper clad laminates and PCB processing requirements. The porogen used in Comparison Example 4 is ammonium bicarbonate having a decomposition temperature of about 40 C. During the sizing process, the porogen is completely decomposed, thereby being unable to reduce the dielectric constant.

[0059] On the other hand, it can be seen from the performance test results in Table 3 that soluble high-temperature porogens in different thermosetting resin systems (Example 5 and Comparison Example 5 are phenolic aldehyde-cured epoxy systems; Example 6 and Comparison Example 6 are cyanate ester-epoxy systems; Example 7 and Comparison Example 7 are polyphenylene ether systems; Example 8 and Comparison Example 8 are epoxy-benzoxazine systems) can reduce the dielectric constant, without reducing the glass transition temperature, peeling strength or tensile strength, and can increase the bending strength of the sheets to a certain degree.

[0060] 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.