Epoxy resin composition, prepreg and laminate prepared therefrom

Abstract

The present invention relates to an epoxy resin composition, comprising the following components: (A) an epoxy resin containing oxazolidinone structure having the structure of the formula (1), (B) an active ester curing agent, and (C) a curing accelerator. The epoxy composition, prepreg, laminate and printed circuit board prepared from such epoxy composition have the following features of low coefficient of thermal expansion, low dielectric loss factor Df less than or equal to 0.0084, low water absorption and excellent moisture and heat resistance.

Claims

1. An epoxy resin composition, characterized in comprising the following components: (A) an epoxy resin containing oxazolidinone structure having the structure of the formula (1) ##STR00016## wherein m and n are each independently selected from the group consisting of 0, 1 and 2; ##STR00017## R and R each is independently selected from ##STR00018## (B) an active ester curing agent; (C) a curing accelerator; and (D) a cyanate ester resin; wherein the component (B) active ester curing agent is an active ester comprising the structure of formula (3): ##STR00019## wherein Y is phenyl or naphthyl; j is 0 or 1; k is 0 or 1; n represents that the repeating unit is 0.25-1.25.

2. The epoxy resin composition according to claim 1, characterized in that in the structure of formula (1), m=0, and n=0; the component (A) comprises an epoxy resin containing oxazolidinone structure having the structure of the formula (2) ##STR00020## wherein R and R have the same scope as claim 1.

3. The epoxy resin composition according to claim 1, characterized in that R and R are the same.

4. The epoxy resin composition according to claim 1, characterized in that the epoxy resin composition further comprises a filler which is an organic filler or/and an inorganic filler.

5. The epoxy resin composition according to claim 4, characterized in that based on the sum of the addition amounts of the components (A) epoxy resin containing oxazolidinone structure, (B) active ester curing agent, and (C) curing accelerator being 100 parts by weight, the filler is added in an amount of 100 parts by weight or less.

6. The epoxy resin composition according to claim 4, characterized in that the inorganic filler is anyone selected from the group consisting of molten silica, crystal silica, spherical silica, hollow silica, aluminum hydroxide, alumina, talc, aluminum nitride, boron nitride, silicon carbide, barium sulfate, barium titanate, strontium titanate, calcium carbonate, calcium silicate, mica or glass fiber cloth, or a mixture of at least two selected therefrom.

7. The epoxy resin composition according to claim 4, characterized in that the organic filler is anyone selected from the group consisting of polytetrafluoroethylene powder, polyphenylene sulfide or polyether sulfone, or a mixture of at least two selected therefrom.

8. The epoxy resin composition according to claim 4, characterized in that the filler is silica; the medium value of the particle size of the filler is from 1 to 15 m.

9. A prepreg comprising a reinforcing material and the epoxy resin composition according to claim 1 attached thereon after impregnation and drying.

10. A laminate comprising at least one sheet of the prepreg according to claim 9.

11. The epoxy resin composition according to claim 1, characterized in that the component (A) epoxy resin containing oxazolidinone structure and the component (B) active ester curing agent have an epoxide equivalent/ester group equivalent ratio of 1:0.9-1.1.

12. The epoxy resin composition according to claim 1, characterized in that the component (C) curing accelerator is anyone selected from the group consisting of 4-dimethylaminopyridine, 2-methylimidazole, 2-ethyl-4-methyl-imidazole or 2-phenylimidazole, or a mixture of at least two selected therefrom.

13. The epoxy resin composition according to claim 1, characterized in that based on the sum of the addition amounts of the components (A) epoxy resin containing oxazolidinone structure and (B) active ester curing agent being 100 parts by weight, the component (C) curing accelerator is added in an amount of from 0.05 to 1 part by weight.

14. The epoxy resin composition according to claim 13, characterized in that based on the sum of the addition amounts of the components (A) epoxy resin containing oxazolidinone structure, (B) active ester curing agent and (C) curing accelerator being 100 parts by weight, the cyanate ester resin is added in an amount of 50 parts by weight or less.

15. The epoxy resin composition according to claim 1, characterized in that the epoxy resin composition further comprises a flame retardant; the flame retardant is a bromine-containing flame retardant or/and halogen-free flame retardant.

16. The epoxy resin composition according to claim 15, characterized in that the flame retardant is added in an amount of from 5 to 50 parts by weight, based on the sum of the addition amounts of the components (A), (B) and (C).

17. The epoxy resin composition according to claim 15, characterized in that the bromine-containing flame retardant is anyone selected from the group consisting of decabromodiphenyl ethane, brominated polystyrene, ethylene bis-tetrabromo phthalimide or bromine-containing epoxy resin, or a mixture of at least two selected therefrom.

18. The epoxy resin composition according to claim 15, characterized in that the halogen-free flame retardant is anyone selected from the group consisting of tri(2,6-dimethylphenyl)phosphine, 10-(2,5-dihydroxylphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,6-di(2,6-dimethylphenyl)-phosphinophenyl; 10-phenyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenoxyphosphazene compound, zinc borate, nitrogen and phosphorus-based intumescent, organic polymer flame retardant, and copolymers of phosphorus-containing phenolic resin or phosphorus-containing bismaleimide, polyphosphonate, phosphonate and carbonate, or a mixture of at least two selected therefrom.

Description

EMBODIMENTS

(1) The technical solution of the present invention is further explained by the following embodiments.

(2) Those skilled in the art should know that the examples are only for understanding the present invention, and shall not be deemed as specific limits to the present invention.

(3) An epoxy resin composition metal-clad laminate prepared thereby was tested for the glass transition temperature, thermal decomposition temperature, coefficient of thermal expansion, dielectric constant, dielectric loss factor, PCT and PCT water absorption, which were stated and described in detail in the following examples, wherein the mass part of organic resins is based on the mass part of the organic solid matter.

(4) Epoxy resins having different structures according to claim 1 were synthesized by the method of preparing the epoxy resin containing oxazolidinone structure by conventionally reacting epoxy resins with polyisocyanate disclosed in U.S. Pat. No. 5,112,932.

Synthesis Example 1

(5) Synthesis of epoxy resins containing bisphenol-A structure and diphenylmethane structure, having the following structure

(6) ##STR00006##
wherein

(7) ##STR00007##
R and R both are

(8) ##STR00008##

(9) Into a three-necked flask (1000 mL) equipped with a stirrer, a thermometer and a reflux condenser was added 400 g of bisphenol-A epoxy resin, which was heated to 145-150 C. under the protection of nitrogen gas. 2-phenylimidazole (0.175 g) was added and then heated to 160 C. At 160 C., 100 g of diphenylmethanediisocyanate (MDI) was dropwise added to the aforesaid mixed solution within 30 min. After MDI was added, thermostatic reaction was carried out at 160 C. under the protection of nitrogen gas, and stopped after 15 min. The reacted solution was slowly added into stirred distilled water, to separate out the polymer, filtrated, water-washed, dried, impregnated with methanol for 24 h, vacuum-dried to obtain the product.

Synthesis Example 2

(10) Synthesis of epoxy resins containing tetrabromo-bisphenol-A structure and diphenylmethane structure, having the following structure

(11) ##STR00009##
wherein

(12) ##STR00010##

(13) Into a three-necked flask (1000 mL) equipped with a stirrer, a thermometer and a reflux condenser was added 245 g of bisphenol-A epoxy resin and 185 g of tetrabromo-bisphenol-A epoxy resin, which was heated to 145-150 C. under the protection of nitrogen gas. 0.2 g of 2-phenylimidazole was added and then heated to 160 C. At 160 C., 90 g of diphenyl-methane-diisocyanate (MDI) was dropwise added to the aforesaid mixed solution within 30 min. After MDI was added, thermostatic reaction was carried out at 160 C. under the protection of nitrogen gas, and stopped after 15 min. The reacted solution was slowly added into stirred distilled water, to separate out the polymer, filtrated, water-washed, dried, impregnated with methanol for 24 h, vacuum-dried to obtain the product.

Synthesis Example 3

(14) Synthesis of epoxy resins containing bisphenol-A structure and 2,4-toluene structure, having the following structure

(15) ##STR00011##
wherein

(16) ##STR00012##
R and R both are

(17) ##STR00013##

(18) Into a three-necked flask (1000 mL) equipped with a stirrer, a thermometer and a reflux condenser was added 400 g of bisphenol-A epoxy resin, which was heated to 135-140 C. under the protection of nitrogen gas. 0.175 g of 2-phenylimidazole was added and then heated to 160 C. At 160 C., 100 g of toluene-2,4-diisocyanate (TDI) was dropwise added to the aforesaid mixed solution within 30 min. After TDI was added, thermostatic reaction was carried out at 160 C. under the protection of nitrogen gas, and stopped after 15 min. The reacted solution was slowly added into stirred distilled water, to separate out the polymer, filtrated, water-washed, dried, impregnated with methanol for 24 h, vacuum-dried to obtain the product.

Synthesis Example 4

(19) Synthesis of epoxy resins containing tetrabromo-bisphenol-A structure and 2,4-toluene structure, having the following structure

(20) ##STR00014##
wherein

(21) ##STR00015##

(22) Into a three-necked flask (1000 mL) equipped with a stirrer, a thermometer and a reflux condenser was added 245 g of bisphenol-A epoxy resin and 185 g of tetrabromo-bisphenol-A epoxy resin, which was heated to 135-140 C. under the protection of nitrogen gas. 0.2 g of 2-phenylimidazole was added and then heated to 160 C. At 160 C., 90 g of toluene-2,4-diisocyanate (TDI) was dropwise added to the aforesaid mixed solution within 30 min. After TDI was added, thermostatic reaction was carried out at 160 C. under the protection of nitrogen gas, and stopped after 15 min. The reacted solution was slowly added into stirred distilled water, to separate out the polymer, filtrated, water-washed, dried, impregnated with methanol for 24 h, vacuum-dried to obtain the product.

Example 1

(23) Into a container was added 60 parts by weight of the product in Synthesis Example 1. A suitable amount of MEK was added and stirred till complete dissolution. Then an active ester and a curing accelerator DMAP dissolved in advance were added and homogeneously stirred. Finally a solvent was used to adjust the solid content of the liquid to 60-80% so as to obtain a glue solution. A glass fiber cloth was impregnated with the aforesaid glue solution, and to control the thickness thereof, and then dried to remove the solvent to obtain a prepreg. Several prepregs were overlapped with each other, coated with one sheet of RTF copper foil on each side thereof, placed into a thermocompressor and cured to obtain said epoxy resin copper-clad laminate. The formulation and physical properties thereof are shown in Table 1.

Example 2

(24) Into a container was added 65 parts by weight of the product in Synthesis Example 1. A suitable amount of MEK was added and stirred till complete dissolution. Then an active ester and a curing accelerator DMAP dissolved in advance were added and homogeneously stirred. Cyanate and zinc isoocatanoate dissolved in advance were added. Finally a solvent was used to adjust the solid content of the liquid to 60-80% so as to obtain a glue solution. A glass fiber cloth was impregnated with the aforesaid glue solution, and to control the thickness thereof, and then dried to remove the solvent to obtain a prepreg. Several prepregs were overlapped with each other, coated with one sheet of RTF copper foil on each side thereof, placed into a thermocompressor and cured to obtain said epoxy resin copper-clad laminate. The formulation and physical properties thereof are shown in Table 1.

Example 3

(25) The preparation process was the same as Example 2. The formulation and physical properties thereof are shown in Table 1.

Examples 4-8

(26) The preparation processes were the same as Example 1. The formulations and physical properties thereof are shown in Table 1.

Example 9

(27) Into a container was added 60 parts by weight of the product in Synthesis Example 1. A suitable amount of MEK was added and stirred till complete dissolution. Then an active ester and a curing accelerator DMAP dissolved in advance were added, and a suitable proportion of fillers were added and homogeneously stirred. Finally a solvent was used to adjust the solid content of the liquid to 60-80% so as to obtain a glue solution. A glass fiber cloth was impregnated with the aforesaid glue solution, and to control the thickness thereof, and then dried to remove the solvent to obtain a prepreg. Several prepregs were overlapped with each other, coated with one sheet of RTF copper foil on each side thereof, placed into a thermocompressor and cured to obtain said epoxy resin copper-clad laminate. The formulation and physical properties thereof are shown in Table 1.

Example 10

(28) The preparation process was the same as Example 9. The formulation and physical properties thereof are shown in Table 1.

Example 11

(29) Into a container was added 65 parts by weight of the product in Synthesis Example 1. A suitable amount of MEK was added and stirred till complete dissolution. Then an active ester and a curing accelerator DMAP dissolved in advance were added and homogeneously stirred. Cyanate and zinc isoocatanoate dissolved in advance were added, and a suitable proportion of fillers were added and homogeneously stirred. Finally a solvent was used to adjust the solid content of the liquid to 60-80% so as to obtain a glue solution. A glass fiber cloth was impregnated with the aforesaid glue solution, and to control the thickness thereof, and then dried to remove the solvent to obtain a prepreg. Several prepregs were overlapped with each other, coated with one sheet of RTF copper foil on each side thereof, placed into a thermocompressor and cured to obtain said epoxy resin copper-clad laminate. The formulation and physical properties thereof are shown in Table 1.

Examples 12-14

(30) The preparation processes were the same as Example 11. The formulations and physical properties thereof are shown in Table 1.

Comparison Examples 1-4

(31) The preparation processes were the same as Example 1. The formulations and physical properties thereof are shown in Table 2.

Comparison Examples 5-6

(32) The preparation processes were the same as Example 2. The formulations and physical properties thereof are shown in Table 2.

(33) The formulations and performance test results in Examples 1-8 are shown in Table 1; the formulations and performance test results in Examples 9-14 are shown in Table 2; the formulations and performance test results in Example 1 and Comparison Examples are shown in Table 3. Table 2

(34) TABLE-US-00001 TABLE 1 The formulations and performance test results in Examples 1-8 Examples Formulation Substances 1 2 3 4 5 6 7 8 Epoxy resin Synthesis 60 65 65 60 60 Example 1 Synthesis 60 Example 2 Synthesis 60 Example 3 Synthesis 60 Example 4 Active ester Active ester 1eq 35 35 0.9eq 1.1eq 1eq 1eq 1eq Cyanate Cyanate / 10 40 / / / / / Accelerator DMAP q.s. q.s. q.s. q.s. q.s. q.s. q.s. q.s. Zinc / q.s. q.s. / / / / / isoocatanoate Performance CTE 3.4% 3.2% 3.1% 3.4% 3.3% 3.3% 3.4% 3.4% Df 0.0082 0.0080 0.0075 0.0083 0.0081 0.0084 0.0083 0.0084 PCT water 0.17% 0.24% 0.26% 0.18% 0.17% 0.20% 0.18% 0.20% absorption PCT 0/3 0/3 0/3 0/3 0/3 0/3 0/3 0/3

(35) TABLE-US-00002 TABLE 2 The formulations and performance test results in Examples 9-14 Examples Formulation Substances 9 10 11 12 13 14 Epoxy resin Synthesis 60 60 65 65 65 65 Example 1 Active ester Active ester 1eq 1eq 35 35 35 35 Cyanate Cyanate / / 10 10 40 40 Accelerator DMAP q.s. q.s. q.s. q.s. q.s. q.s. Zinc q.s. q.s. q.s. q.s. isoocatanoate Filler Spherical silica 30 30 30 powder Molten silica 30 30 30 powder Performance CTE 3.0% 3.3% 3.3% 3.2% 2.8% 2.8% Df 0.0074 0.0079 0.0073 0.0078 0.0071 0.0073 PCT water 0.36% 0.44% 0.39% 0.46% 0.41% 0.46% absorption PCT 0/3 0/3 0/3 0/3 0/3 0/3

(36) TABLE-US-00003 TABLE 3 The formulations and performance test results in Example 1 and Comparison Examples Comparison Examples Formulation Substances Example 1 1 2 3 4 5 6 Epoxy resin Synthesis 60 60 Example 1 Epoxy resin 1 60 60 65 65 Epoxy resin 2 60 Active ester Active ester 1eq 1eq 1eq 35 35 Phenolic Phenolic resin 1 / / 1eq 1eq / / / curing agent Cyanate resin Cyanate / / / / / 10 40 Curing DMAP q.s. q.s. q.s. q.s. q.s. q.s. q.s. accelerator Zinc q.s. q.s. isoocatanoate Performance CTE 3.4% 3.6% 3.4% 3.7% 3.5% 3.4% 3.2% Df 0.0082 0.0092 0.0142 0.0174 0.0099 0.0085 0.0088 PCT water 0.17% 0.19% 0.44% 0.67% 0.22% 0.26% 0.30% absorption PCT 0/3 0/3 0/3 3/3 0/3 0/3 0/3

(37) In Tables 1, 2 and 3, when the main resin components in the formulations are bi-component, the curing agent ratio is represented by the equivalent ratio of the epoxy resins. When the main resin components in the formulations are multi-component (beyond bi-component), the curing agent ratio is represented by the solid weight ratio of the epoxy components.

(38) The materials in Tables 1 and 2 are listed as follows.

(39) Epoxy resin 1: biphenyl novolac epoxy resin NC-3000H (Trade name from Nippon Kayaku).

(40) Epoxy resin 2: dicyclopentadiene novolac epoxy resin HP-7200HHH (Trade name from DIC Japan)

(41) Phenolic resin 1: novolac curing agent KPH-2002 (Trade name from KOLON)

(42) Active ester: active ester crosslinking agent HPC-8000-65T (Trade name from DIC Japan)

(43) Cyanate: biphenol A-cyanate resin CEO1PS (Trade name from Yangzhou Apocalypse)

(44) DMAP: Curing accelerator, 4-dimethylaminopyridine (Trade name from Guangrong Chemical Company)

(45) Zinc isoocatanoate: curing accelerator (Trade name from Alfa Aesar)

(46) The aforesaid properties are tested by the following methods: (1) Coefficient of thermal expansion (CTE): tested by the TMA method as stipulated under IPC-TM-6502.4.24.6 of Thermal Mechanical Analyzer (TMA). (2) Dielectric constant and dielectric loss factor: tested by the method as stipulated under IPC-TM-6502.5.5.13, under the frequency of 10 GHz. (3) PCT post-dip soldering resistance evaluation: etching the copper foil on the surface of copper-clad plate and evaluating the plate; placing the plate in a pressure cooker and treating at 120 C. and 105 Kpa for 2 h; impregnating at 288 C. in a solder machine, and recording the corresponding time when the delamination of the plate happens; finishing the evaluation when there is no bubbles or delamination after the plate is placed in the solder machine for more than 5 min. If there is 0, 1, 2 and 3 having bubbles or delamination in three plates, 0/3, 1/3, 2/3 and 3/3 are marked. (4) PCT water absorption: etching the copper foil on the surface of copper-clad plate, weighing and recording as m.sub.1, placing the plate into a pressure cooker, treating at 120 C. and 105 Kpa for 2 h, drying the sample with dry cloth and weighing immediately and recording as m.sub.2. PCT water absorption %=(m.sub.2m.sub.1)/m.sub.1100%.

(47) Physical Property Analyses (1) By comparing Examples 2, 3 with 1, it can be seen that the coefficient of thermal expansion and dielectric loss factor in Examples 2 and 3 are lower than those in Example 1, but the water absorption is higher than that in Example 1, which shows that the introduction of cyanate can reduce the coefficient of thermal expansion and dielectric loss factor of the composition, but increase the water absorption of the composition. (2) By comparing Example 2 with 3, it can be seen that the coefficient of thermal expansion and dielectric loss factor in Example 3 are lower than those in Example 2, but the water absorption is higher than that in Example 1, which shows that the composition has lower dielectric loss factor and higher water absorption along with the increase of cyanate content. (3) By comparing Examples 6, 7, 8 with 1, it can be seen that they all have similar dielectric loss factor and water absorption. However, the Br-containing components have relatively greater water absorption and dielectric loss factor. In addition, the epoxy resin containing diphenylmethane structure has better symmetry as compared to that containing methyl structure, so as to have lower dielectric loss factor. (4) Examples 9-14 show that the composition into which the filler is added has a decreased coefficient of thermal expansion and dielectric loss factor, but an increased water absorption, and an excellent moisture and heat resistance. As compared to the molten silica powder, spherical silica powder can bring lower dielectric loss factor and water absorption. (5) According to Comparison Examples 2 and 3, it can be seen that there is PCT delamination phenomenon for the composition containing oxazolidinone epoxy resin and novolac resin in Comparison Example 3, which shows a worse moisture and heat resistance. There is no delamination phenomenon for the composition containing biphenyl epoxy and novolac resin in Comparison Example 2, and it has a lower dielectric loss factor and water absorption as compared with the composition system in Comparison Example 3. There is no delamination phenomenon for the compositions containing oxazolidinone epoxy resin and active ester resin in Examples 1 and 6-8 as compared to the composition containing biphenyl epoxy and active ester in Comparison Example 1 and the composition containing dicyclopentadiene epoxy and active ester in Comparison Example 4. As compared to other two compositions in Comparison Examples 1 and 4, the composition containing oxazolidinone epoxy resin and active ester resin has a lower dielectric loss factor and a lower water absorption. It can be seen that the epoxy resin containing oxazolidinone structure and active ester can exert the synergistic effect and ensure the composition to have a lower dielectric loss factor, a lower expansion coefficient and water absorption and to have the moisture and heat resistance as compared to the compositions using a single component. (6) By comparing Examples 2 and 3 with Comparison Examples 5 and 6, it can be seen that coefficient of thermal expansion, dielectric loss factor and water absorption are lower than those in Comparison Examples 4 and 5, which shows that the introduction of cyanate still can exert the synergistic effect, and make the composition have lower coefficient of thermal expansion, dielectric loss factor and water absorption. (7) According to Examples 1-14, it can be seen that, in the PCT-post-dip soldering resistance evaluation by using the composition of the present invention, none of the experimental samples has delamination or blistering phenomena, which shows that it has excellent moisture and heat resistance.

(48) As stated above, the present invention has low coefficient of thermal expansion, low dielectric loss factor, low water absorption and excellent moisture and heat resistance as compared to general laminates.

(49) The aforesaid examples are merely preferred examples. According to the technical solution and technical concept of the present invention, those ordinarily skilled in the art can make various changes and deformation, which all belong to the scope of the claims of the present invention.

(50) The applicant declares that, the present invention detailedly discloses the process of the present invention by the aforesaid examples, but the present invention is not limited by the detailed process, i.e. it does not mean that the present invention cannot be fulfilled unless the aforesaid detailed process is used. Those skilled in the art shall know that, any amendment, equivalent change to the product materials of the present invention, addition of auxiliary ingredients, and selection of any specific modes all fall within the protection scope and disclosure scope of the present invention.