HALOGEN-FREE EPOXY RESIN COMPOSITION, PREPREG, LAMINATE AND PRINTED CIRCUIT BOARD CONTAINING THE SAME

Abstract

The present invention relates to a halogen-free epoxy resin composition, a prepreg and a laminate containing the same. The halogen-free epoxy resin composition comprises 60 parts by weight of epoxy resin, from 15 to 28 parts by weight of benzoxazine resin, and from 10 to 20 parts by weight of styrene-maleic anhydride. The present invention discloses using from 15 to 28 parts by weight of benzoxazine resin and from 10 to 20 parts by weight of styrene-maleic anhydride to cure 60 parts by weight of epoxy resin, to ensure the Df stability of prepregs at different curing temperature conditions while maintaining low dielectric constant and low dielectric loss. The prepregs and laminates prepared from the resin composition have comprehensive performances, such as low dielectric constant, low dielectric loss, excellent flame retardancy, heat resistance, cohesiveness, low water absorption and moisture resistance, and are suitable for use in halogen-free multilayer circuit boards.

Claims

1. A halogen-free epoxy resin composition, comprising 60 parts by weight of epoxy resin, from 15 to 28 parts by weight of benzoxazine resin, and from 10 to 20 parts by weight of styrene-maleic anhydride.

2. The halogen-free epoxy resin composition claimed in claim 1, wherein the benzoxazine resin is added in an amount of from 20 to 25 parts by weight.

3. The halogen-free epoxy resin composition claimed in claim 1, wherein the styrene-maleic anhydride is added in an amount of from 15 to 18 parts by weight.

4. The halogen-free epoxy resin composition claimed in claim 1, wherein the halogen-free epoxy resin composition comprises 60 parts by weight of epoxy resin, from 20 to 25 parts by weight of benzoxazine resin, and from 15 to 18 parts by weight of styrene-maleic anhydride.

5. The halogen-free epoxy resin composition claimed in claim 1, wherein the halogen-free epoxy resin composition further comprises a phosphorus-containing flame retardant.

6. The halogen-free epoxy resin composition claimed in claim 5, wherein the phosphorus-containing flame retardant comprises a phosphorus-containing novolac and a phosphorus-nitrogen based compound.

7. The halogen-free epoxy resin composition claimed in claim 5, wherein the phosphorus-containing flame retardant comprises from 10 to 40 parts by weight of a phosphorus-containing novolac and from 10 to 50 parts by weight of a phosphorus-nitrogen based compound.

8. The halogen-free epoxy resin composition claimed in claim 1, wherein the epoxy resin is anyone selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin, alkyl novolac epoxy resin, dicyclopentadiene epoxy resin, bisphenol A novolac epoxy resin, o-cresol novolac epoxy resin, phenol novolac epoxy resin, tetrafunctional epoxy resin, isocyanate-modified epoxy resin, naphthalene epoxy resin and phosphorus-containing epoxy resin, or a mixture of at least two selected therefrom ##STR00004## ##STR00005##

9. The halogen-free epoxy resin composition claimed in claim 1, wherein the benzoxazine resin is anyone selected from the benzoxazine resins having the following structures, or a combination of at least two selected therefrom; ##STR00006## wherein R.sub.2 and R.sub.3 are mono- or poly-substituted, and are each independently selected from the group consisting of hydrogen, methyl, allyl and formyl group; R.sub.1 is anyone selected from the group consisting of —CH.sub.2—, —O—, —C(CH.sub.3).sub.2—, —SO.sub.2—, —C(CF.sub.3).sub.2—, —CH.sub.2CH.sub.2— and dicyclopentadiene, or a combination of at least two selected therefrom; R.sub.4 and R.sub.5 are each independently anyone selected from the group consisting of allyl, unsubstituted or substituted phenyl, unsubstituted or substituted alkyl having 1-8 carbon atoms and cycloalkyl having 1-8 carbon atoms, or a combination of at least two selected therefrom.

10. The halogen-free epoxy resin composition claimed in claim 1, wherein the styrene-maleic anhydride has a structural formula of: ##STR00007## wherein x:n=0.8-19:1.

11. The halogen-free epoxy resin composition claimed in claim 1, wherein the styrene-maleic anhydride has a number average molecular weight of 1000-50000.

12. The halogen-free epoxy resin composition claimed in claim 6, wherein the phosphorus-containing novolac is anyone selected from the group consisting of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified novolac resin, 10-(2,5-dihydroxylphenyl)9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified novolac resin, 10-(2,9-dihydroxylnaphthyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-modified novolac resin, or a mixture of at least two selected therefrom

13. The halogen-free epoxy resin composition claimed in claim 6, wherein the phosphorus-nitrogen based compound has the following structure: ##STR00008## wherein n is a positive integer greater than 1.

14. The halogen-free epoxy resin composition claimed in claim 1, wherein the halogen-free epoxy resin composition further comprises a halogen-free flame retardant selected from the group consisting of ammonium polyphosphate, tri(2-carboxyethyl)phosphine, tri(isopropylchloro)phosphate, trimethyl phosphate, dimethyl-methyl phosphate, resorcinol bis-xylyl phosphate, melamine polyphosphate, melamine cyanurate and tri-hydroxyethyl isocyanurate, or a combination of at least two selected therefrom.

15. The halogen-free epoxy resin composition claimed in claim 1, wherein the halogen-free epoxy resin composition further comprises from 20 to 100 parts by weight of a filler.

16. The halogen-free epoxy resin composition claimed in claim 15, wherein the filler is an organic and/or inorganic filler.

17. The halogen-free epoxy resin composition claimed in claim 16, wherein the inorganic filler is anyone selected from the group consisting of aluminum hydroxide, alumina, magnesium hydroxide, magnesium oxide, aluminum oxide, silica, calcium carbonate, aluminum nitride, boron nitride, silicon carbide, titanium dioxide, zinc oxide, zirconium oxide, mica, boehmite, calcined talc, talcum powder, silicon nitride and calcined kaolin, or a mixture of at least two selected therefrom; the organic filler is anyone selected from the group consisting of polytetrafluoroethylene powder, polyphenylene sulfide and polyether sulfone powder, or a mixture of at least two selected therefrom.

18. The halogen-free epoxy resin composition claimed in claim 15, wherein the filler has a particle size of from 0.01 to 50 μm.

19. The halogen-free epoxy resin composition claimed in claim 1, wherein the halogen-free epoxy resin composition comprises a curing accelerator which is anyone selected from imidazole accelerators.

20. The halogen-free epoxy resin composition claimed in claim 19, wherein the curing accelerator is anyone selected from the group consisting of 2-methyl imidazole, undecyl imidazole, 2-ethyl-4-methyl imidazole, 2-phenyl imidazole and 1-cyanoethyl-substituted imidazole, or a combination of at least two selected therefrom.

21. A prepreg comprising a reinforcing material and the halogen-free epoxy resin composition in claim 1 attached thereon after impregnation and drying.

22. A laminate, comprising at least one overlapped prepreg claimed in claim 21.

23. A printed circuit board, comprising at least one overlapped prepreg claimed in claim 21.

Description

EMBODIMENTS

[0055] The technical solution of the present invention is further stated by the following specific embodiments.

[0056] As for the resin composition for use in prepregs and laminates of the present invention, the peeling strength, glass transition temperature, flame retardancy, dip soldering resistance limit after two hours of PCT, water absorption and dielectric constant of substrates cured at 200° C. for 120 min were tested, and the dielectric loss performance was tested at different curing temperatures. The following examples provide further description.

[0057] Epoxy resin, benzoxazine, styrene-maleic anhydride, phosphorus-containing novolac, phosphorus-nitrogen based compound, filler and other auxiliaries were fed into a container, stirred and homogeneously mixed to make a glue. A solvent was used to adjust the solid content of the solution to 60 wt %-70 wt % to obtain a glue solution, i.e. the resin composition glue solution of the present invention. A glass fabric having 2116 electronic grade was impregnated with the glue, baked with an oven to prepare a prepreg. Six sheets of 2116 prepregs were covered by both sides with electrolytic copper foils having a thickness of 35 μm, vacuum-laminated by a thermocompressor, cured at 190° C., 200° C. and 210° C. for 120 min to obtain a copper-clad plate.

[0058] The components in the examples and comparison examples are stated as follows.

[0059] (A) Epoxy resin

[0060] (A-1) NC-3000-H (Trade name from Japan Chemical)

[0061] (A-2) HP-7200H (Trade name from Dainippon Ink)

[0062] (B) Benzoxazine

[0063] (B-1) D-125 (Trade name from Sichuan East wood Technology Group Co., Ltd)

[0064] (B-2) LZ8280 (Trade name from Huntsman Advanced Materials)

[0065] (C) Styrene-maleic anhydride oligomer: SMA-EF40 (Trade name from Sartomer)

[0066] (D-1) Dicyandiamide: DICY (Trade name from Ningxia Darong)

[0067] (D-2) Polyester: EXB-9460

[0068] (E) Phosphorus-containing novolac resin

[0069] (E-1) XZ92741 (Trade name from DOW)

[0070] (E-2) LC-950 (Trade name from SHIN-A)

[0071] (F) Phosphorus-nitrogen compounds: SPB-100 (Trade name from Otsuka Chemical Corporation)

[0072] (G) Filler: molten silica

TABLE-US-00001 TABLE 1 Com. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 1 A-1 60 60 60 60 30 60 60 60 60 A-2 60 30 B-1 15 23 28 23 20 25 23 10 B-2 23 28 C 10 16 20 16 20 15 18 15 16 16 E-1 18 18 18 E-2 40 10 F 30 10 50 30 30 G 50 50 100 50 Com. Com. Com. Com. Com. Com. Com. Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 A-1 60 30 30 A-2 60 60 30 30 60 60 B-1 40 B-2 23 23 28 28 23 23 C 16 5 40 15 15 20 20 E-1 18 E-2 18 40 5 50 40 40 F 30 10 10 50 50 5 60 G 50 50 50 100 100 50 50

TABLE-US-00002 TABLE 2 Example Example Example Example Example Example Com. Com. Com. Testing items 1 2 3 4 5 6 Example 1 Example 2 Example 3 Tg(DSC) (° C.) 178 185 188 182 182 180 170 190 171 Peeling strength 1.32 1.32 1.25 1.35 1.28 1.30 1.30 1.35 1.30 (N/mm) Combustibility V-1 V-1 V-1 V-0 V-0 V-0 V-0 V-0 V-0 PCT(min) >5 >5 >5 >5 >5 >5 >5 >5 >5 PCT water 0.32 0.32 0.35 0.33 0.36 0.33 0.35 0.36 0.36 absorption % Processability Good Good Good Good Good Good Good Worse Worse Dielectric constant 3.9 3.9 3.9 3.9 3.9 3.9 4.0 3.9 4.0 (1 GHz) Dielectric 190° C./ 0.007 0.0063 0.0063 0.0063 0.0067 0.0065 0.0075 0.0063 0.008 loss 120 min (1 GHz) 200° C./ 0.007 0.0063 0.0063 0.0063 0.0067 0.0065 0.0075 0.0072 0.008 120 min 210° C./ 0.007 0.0063 0.0063 0.0063 0.0067 0.0065 0.0075 0.0080 0.008 120 min

TABLE-US-00003 TABLE 3 Example Example Example Com. Com. Com. Com. Com. Testing items 7 8 9 Example 4 Example 5 Example 6 Example 7 Example 8 Tg(DSC) (° C.) 184 184 182 188 182 175 184 170 Peeling strength 1.33 1.33 1.32 1.02 1.30 1.30 1.30 1.30 (N/mm) Combustibility V-1 V-1 V-0 V-1 V-1 V-0 V-1 V-0 PCT(min) >5 >5 >5 >5 >5 4 >5 4 PCT water 0.32 0.32 0.32 0.40 0.32 0.41 0.36 0.36 absorption % Processability Good Good Good Good Good Good Good Worse Dielectric constant 3.9 3.9 3.9 3.9 3.9 3.9 3.9 3.9 (1 GHz) Dielectric 190° C./ 0.0063 0.0063 0.0063 0.006 0.0065 0.0068 0.0067 0.0067 loss 120 min (1 GHz) 200° C./ 0.0063 0.0063 0.0063 0.0068 0.0065 0.0068 0.0067 0.0067 120 min 210° C./ 0.0063 0.0063 0.0063 0.0078 0.00654 0.0068 0.0067 0.0067 120 min

[0073] According to Tables 1-3:

[0074] According to Example 1 and Examples 2, 7, 8, it can be seen that the formulae obtained by optimizing with curing agents has a lower Df value and a high Tg.

[0075] According to Examples 2, 7, 8 and Example 3, it can be seen that, although the formulae optimized with curing agents has a lower Tg, it has a higher peeling strength and a lower water absorption. That is to say, it can be seen according to Examples 1-3, 7 and 8 that the formulae optimized with curing agents has better comprehensive performances.

[0076] According to a comparison of Example 2 and Examples 4 and 9, it can be seen that, although Tg is slightly reduced after the addition of phosphorus-containing novolac and phosphorus-nitrogen based compounds, it can be ensured that the flame retardancy can achieve V-0, and there is no effect on other performances. In addition, the addition of fillers has little effect on the substrate performance.

[0077] According to Example 4 and Comparison Examples 1-2, it can be seen that, when benzoxazine is in an amount less than 15 parts by weight, the Tg thereof is lower, and the dielectric performances are worse; when benzoxazine is in an amount higher than 28 parts by weight, the processability thereof is worse, and Df is unstable and increases along with the increase of the curing temperature, although it has a higher Tg.

[0078] According to Example 5 and Comparison Examples 3-4, it can be seen that, when styrene-maleic anhydride is in an amount less than 10 parts by weight, Tg is insufficient, and the dielectric loss performance is worse, which will affect the processability of the substrate; when the amount is higher than 20 parts by weight, the flame retardancy is insufficient although Tg can increase; the water absorption increases; the Df is unstable and will increase along with the increase of the curing temperature.

[0079] According to Example 6 and Comparison Examples 5-6, it can be seen that, when phosphorus-containing novolac is in an amount less than 10 parts by weight, the flame retardancy cannot achieve the V-0 level; when phosphorus-containing novolac is in an amount higher than 40 parts by weight, such amount can ensure the flame retardancy, but increase the water absorption of the substrate and decrease the Tg, and will affect the PCT performance of the substrate.

[0080] According to Example 5 and Comparison Examples 7-8, it can be seen that, when the phosphorus-nitrogen based compound is in an amount less than 10 parts by weight, the flame retardancy cannot achieve the V-0 level; when the phosphorus-nitrogen based compound is in an amount higher than 50 parts by weight, such amount can ensure the flame retardancy, but decrease the Tg, and will affect the PCT performance and processability of the substrate.

Comparison Example 9

[0081] Comparison Example 9 is Example 4 disclosed in CN 101684191B.

Comparison Example 10

[0082] Comparison Example 10 is Example 1 disclosed in CN103131131A.

Comparison Example 11

[0083] Comparison Example 11 is Example 2 disclosed in CN 103881302A.

TABLE-US-00004 TABLE 4 Com. Com. Com. Example 9 Example 10 Example 11 A-1 60 35 35 A-2 25 25 B-1 115 30 B-2 42 C 42 6 18 D-1 0.9 D-2 12 E-1 44 24 E-2 F 21 G 21 31

TABLE-US-00005 TABLE 5 Com. Com. Com. Testing items Example 9 Example 10 Example 11 Tg(DSC) (° C.) 175 167 170 Peeling strength (N/mm) 1.27 1.38 1.32 Combustibility V-1 V-0 V-0 PCT(min) >5 3 >5 PCT water absorption % 0.32 0.40 0.34 Processability Good Good Good Dielectric constant (1 GHz) 4.0 3.9 3.9 Dielectric 190° C./120 min 0.006 0.009 0.006 loss (1 GHz) 200° C./120 min 0.0068 0.009 0.0065 210° C./120 min 0.0072 0.009 0.0072

[0084] According to Examples 1-9, it can be seen that the laminates prepared from the halogen-free resin composition of the present invention have better dielectric performances, the dielectric loss value will not change along with the increase of the curing temperature and can achieve the V-0 standard in the flame retardancy test UL-94. Thus, while ensuring the halogen-free flame retardancy, the laminates also have comprehensive performances, such as low dielectric constant, low dielectric loss, excellent heat resistance, cohesiveness and moisture resistance, and are suitable for use in halogen-free high multi-layer circuit boards. The prepregs and laminates prepared from the resin composition of the present invention have comprehensive performances, such as low dielectric constant, low dielectric loss, excellent flame retardancy, heat resistance, cohesiveness and moisture resistance, overcome the shortcomings of the current halogen-free laminates, such as insufficient heat resistance and worse moisture resistance and are suitable for use in halogen-free high multi-layer circuit boards.

[0085] The present invention discloses the detailed process via the aforesaid examples. However, the present invention is not limited by the aforesaid detailed process. That is to say, it does not mean that the present invention cannot be carried out unless the aforesaid detailed process is used. Those skilled in the art shall know that any improvement, equivalent replacement of various raw materials of the present invention, addition of auxiliary ingredients, selection of specific modes and the like all fall within the protection scope and disclosure of the present invention.