THERMOSETTING RESIN COMPOSITION, AND PREPREG AND METAL FOIL CLAD LAMINATE MADE THEREFROM

Abstract

Thermosetting resin composition, prepreg and metal foil clad laminate made therefrom. The thermosetting resin composition comprises (A): a solvent-soluble multifunctional vinyl aromatic copolymer, wherein same is a multifunctional vinyl aromatic copolymer having structural units from monomers comprising a divinyl aromatic compound (a) and ethyl vinyl aromatic compound (b); and (B), wherein same is selected from olefin resins having a number-average molecular weight of 500-10,000 and containing 10%-50% by weight of a styrene structure, and the molecules thereof contain a 1,2-addition butadiene structure. The prepreg and copper foil clad laminate made from the thermosetting resin composition of the present invention have a good toughness, and maintain a high glass transition temperature, a low water absorption, excellent dielectric properties and damp heat resistance thereof, and are suitable for use in the field of high frequency and high speed printed circuit boards, and are also suitable for processing multilayer printed circuit boards.

Claims

1-10. (canceled)

11. A thermosetting resin composition, characterized in that the thermosetting resin composition comprises component (A) a solvent soluble polyfunctional vinyl aromatic copolymer having a structural unit derived from monomers comprising divinyl aromatic compound (a) and ethyl vinyl aromatic compound (b), comprising 20 mol. % or more of repeating units derived from divinyl aromatic compound (a), wherein the molar fraction of the vinyl group-containing structural unit derived from the divinyl aromatic compound (a) represented by the following formulae (a1) and (a2) satisfies (a1)/[(a1)+(a2)]0.5; the polystyrene-equivalent number average molecular weight M.sub.n measured by gel permeation chromatography is 600 to 30,000; and the ratio of the weight average molecular weight M.sub.w to the number average molecular weight M.sub.n is 20.0 or less, ##STR00005## wherein R.sub.13 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms; R.sub.14 represents an aromatic hydrocarbon group having 6 to 30 carbon atoms; and component (B) which is selected from olefin resins having a number average molecular weight of 500-10,000, containing 10-50 wt. % of a styrene structure and comprising a butadiene structure added at the 1,2 position in the molecule thereof.

12. The thermosetting resin composition according to claim 11, characterized in that the olefin resin is a butadiene-styrene copolymer and/or butadiene-styrene-divinylbenzene copolymer.

13. The thermosetting resin composition according to claim 11, characterized in that, in the thermosetting resin composition, the compounding amount of the component (A) is 10 to 98 wt. %, and the compounding amount of the component (B) is 2 to 90 wt. %, based on the total weight of the components (A) and (B).

14. The thermosetting resin composition according to claim 11, wherein the main chain skeleton of the soluble polyfunctional vinyl aromatic copolymer has an indane structure represented by the following formula (a.sub.3) ##STR00006## wherein W represents a saturated or unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group, or an aromatic ring or a substituted aromatic ring fused to a benzene ring; Z is an integer of 0 to 4.

15. The thermosetting resin composition according to claim 11, wherein the soluble polyfunctional vinyl aromatic copolymer has a number average molecular weight M.sub.n of 600-10,000.

16. The thermosetting resin composition according to claim 11, wherein, the soluble polyfunctional vinyl aromatic copolymer has a number average molecular weight distribution M.sub.w/M.sub.n value of less than or equivalent to 15.

17. The thermosetting resin composition according to claim 11, wherein the soluble polyfunctional vinyl aromatic copolymer has a metal ion content of less than or equivalent to 500 ppm, more preferably less than or equivalent to 100 ppm, further preferably less than or equivalent to 20 ppm, most preferably less than or equivalent to 1 ppm based on the total content of various metal ions.

18. The thermosetting resin composition according to claim 11, characterized in that the component (A) is a soluble polyfunctional vinyl aromatic copolymer containing a structural unit of monovinyl aromatic compounds (c) other than the ethyl vinyl aromatic compounds (b).

19. The thermosetting resin composition according to claim 11, characterized in that there further contains an initiator as the component (C) in addition to the components (A) and (B); the component (C) is used in an amount of 0.1 to 10 by weight based on 100 parts by weight of the component (A) and the component (B).

20. The thermosetting resin composition according to claim 11, wherein the component (C) initiator has a half-life temperature t.sub.1/2 of not less than 130 C.; the initiator is a radical initiator.

21. The thermosetting resin composition according to claim 11, wherein the thermosetting resin composition further comprises a filler, wherein the filler comprises an organic filler and/or an inorganic filler.

22. The thermosetting resin composition according to claim 11, wherein the thermosetting resin composition further comprises a flame retardant, wherein the flame retardant may be a bromine-containing flame retardant or a halogen-free flame retardant.

23. The thermosetting resin composition according to claim 11, wherein the thermosetting resin composition further comprises an antioxidant, a heat stabilizer, a light stabilizer, a plasticizer, a lubricant, a flow modifier, an anti-drip agent, an anti-blocking agent, an antistatic agent, a flow promoter, a processing aid, a substrate binder, a mold release agent, a toughening agent, a low shrinkage additive and a stress relief additive, or a combination of at least two selected therefrom.

24. A resin varnish, characterized in that it is obtained by dissolving or dispersing the thermosetting resin composition according to claim 11 in a solvent.

25. A prepreg, characterized in that the prepreg comprises a substrate and the thermosetting resin composition according to claim 11 adhered to the substrate by impregnation and drying.

26. A laminate, characterized in that the laminate comprises at least one prepreg according to claim 25.

27. A metal foil-clad laminate, comprising one or at least two laminated prepregs according to claim 25, and metal foils on one side or both sides of the laminated prepreg.

28. A high-frequency high-speed circuit board comprising one or at least two laminated prepregs according to claim 25.

Description

EXAMPLE 1

[0104] 80.0 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 20.0 parts by weight of styrene-butadiene copolymer Ricon 100 (from Sartomer, having a styrene content of 25%), 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a 2116 prepreg. 6 sheets of 2116 prepregs and 12 sheets of 2116 prepregs were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm.sup.2, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties).

[0105] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 2

[0106] It was the same as in the process of Example 1, except for that the ratio of the polyfunctional vinyl aromatic copolymer VOD-A and the styrene-butadiene copolymer Ricon 100 had changed from 80:20 to 50:50.

[0107] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 3

[0108] It was the same as in the process of Example 1, except for that the olefin resin component was replaced by styrene-butadiene Ricon 181 (Sartomer, having a styrene content of 28%). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 4

[0109] It was the same as in the process of Example 1, except for that the olefin resin component was replaced by styrene-butadiene-divinylbenzene copolymer Ricon 250 (Sartomer, having a styrene content of 35%). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 5

[0110] It was the same as in the process of Example 4, except for that the ratio of the polyfunctional vinyl aromatic copolymer VOD-A and the styrene-butadiene-divinylbenzene copolymer Ricon 250 had changed from 80:20 to 50:50 in detail.

[0111] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2.

EXAMPLE 6

[0112] It was the same as in the process of Example 1, except for that the ratio of the polyfunctional vinyl aromatic copolymer VOD-A and the styrene-butadiene copolymer Ricon 100 had changed from 80:20 to 13:87 in detail.

[0113] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 7

[0114] It was the same as in the process of Example 1, except for that the ratio of the polyfunctional vinyl aromatic copolymer VOD-A and the styrene-butadiene copolymer Ricon 100 had changed from 80:20 to 93:7. The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

EXAMPLE 8

[0115] It was the same as in the process of Example 1, except for that the polyfunctional vinyl aromatic copolymer VOD-A was replaced by the polyfunctional vinyl aromatic copolymer VOD-B. The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 2 in detail.

Comparison Example 1

[0116] 100 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a 2116 prepreg. 6 sheets of 2116 prepregs and 12 sheets of 2116 prepregs were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm.sup.2, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

Comparison Example 2

[0117] 80.0 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 20.0 parts by weight of styrene-butadiene copolymer Ricon 100 (Sartomer, having a styrene content of 25%), 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a prepreg of 2116. 6 sheets of 2116 prepreg and 12 sheets of 2116 prepreg were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm.sup.2, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

Comparison Example 3

[0118] 48 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 12 parts by weight of vinyl modified polyphenylene ether resin OPE-2ST-1, 40 parts by weight of hydrogenated styrene butadiene block copolymer H1041, 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a 2116 prepreg. 6 sheets of 2116 prepregs and 12 sheets of 2116 prepregs were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm.sup.2, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

Comparison Example 4

[0119] 80.0 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 20 parts by weight of methyl-terminated acryloyl cage silsesquioxane A, 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a 2116 prepreg. 6 sheets of 2116 prepregs and 12 sheets of 2116 prepregs were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm.sup.2, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties). The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

Comparison Example 5

[0120] 80.0 parts by weight of the polyfunctional vinyl aromatic copolymer VOD-A, 20.0 parts by weight of styrene-butadiene copolymer D4272 (Kraton, having a styrene content of 53%), 3.0 parts by weight of a radical initiator DCP, 25 parts by weight of a bromine flame retardant BT-93 W, and 60 parts by weight of the silica fine powder S0-C2 were dissolved in a toluene solvent, and adjusted to a suitable viscosity. NE-glass fiber cloth (Nittobo, model 2116NE) was impregnated with the resin varnish, controlled to be suitable for piece weight by a clamping axis, and dried in an oven to remove the toluene solvent, so as to prepare a 2116 prepreg. 6 sheets of 2116 prepregs and 12 sheets of 2116 prepregs were respectively overlapped, and were coated with a copper foil having a thickness of 1 OZ on both the upper and lower sides, vacuum laminated and cured for 120 min in a press at a curing pressure of 50 kg/cm, and a curing temperature of 200 C., to prepare high-speed circuit boards with two thickness specifications (6*2116-0.76 mm plates for testing comprehensive performance, 12*2116-1.52 mm thick plates for testing mechanical properties).

[0121] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

Comparison Example 6

[0122] It was the same as in the process of Comparison Example 5, except for that the olefin rein component was replaced by maleated polybutadiene Ricon 130MA8 (Sartomer, having a styrene content of 35%).

[0123] The physical properties of the prepared copper foil substrate were tested, and the results are shown in Table 3 in detail.

TABLE-US-00002 TABLE 2 Materials and performances Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Copolymer 80 50 80 80 50 13 93 VOD-A Copolymer 80 VOD-B Copolymer VOD-C Ricon 100 20 50 87 7 20 Ricon 181 20 Ricon 250 20 50 Ricon 130MA8 D4272 OPE-2ST-1 H1041 Cage silses- quioxane A DCP 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 BT-93W 25 25 25 25 25 25 25 25 S0-C2 60 60 60 60 60 60 60 60 Tg-DMA( C.) 293.3 269.6 292.2 294.3 272.2 213.2 292.6 291.2 Td-5% loss 416.2 415.3 416.3 413.2 416.3 417.3 416.5 414.2 ( C.) PCT water 0.14 0.15 0.15 0.16 0.16 0.15 0.15 0.14 absorption rate (%) Dielectric 3.40 3.41 3.40 3.41 3.40 3.41 3.41 3.40 constant (10 GHz) Dielectric 0.0020 0.0021 0.0019 0.0021 0.0020 0.0020 0.0020 0.0020 loss factor (10 GHz) Pendulum 63.547 65.368 64.589 64.201 65.365 66.175 62.751 64.547 Impact strength (kJ/m.sup.2) Drop hammer impact toughness PCT >300 s >300 s >300 s >300 s >300 s >300 s >300 s >300 s

TABLE-US-00003 TABLE 3 Materials and Comp. Comp. Comp. Comp. Comp. Comp. performances Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Copolymer 100 48 80 80 80 VOD-A Copolymer VOD-B Copolymer 80 VOD-C Ricon 100 20 Ricon 181 Ricon 250 Ricon 130MA8 20 D4272 20 OPE-2ST-1 12 H1041 40 Cage silses- 20 quioxane A DCP 3.0 3.0 3.0 3.0 3.0 3.0 BT-93W 25 25 25 25 25 25 S0-C2 60 60 60 60 60 60 Tg-DMA( C.) 291.6 210.3 202.6 289.3 288.2 285.3 Td-5% loss 416.2 360.2 412.3 414.2 413.3 410.3 ( C.) PCT water 0.14 0.15 0.25 0.15 0.14 0.15 absorption rate (%) Dielectric 3.40 3.40 3.43 3.55 3.41 3.54 constant (10 GHz) Dielectric 0.0020 0.0020 0.0030 0.0050 0.0021 0.0052 loss factor (10 GHz) Pendulum 45.687 58.654 55.501 54.632 46.598 52.132 Impact strength (kJ/m.sup.2) Drop hammer impact toughness PCT >300 s 10 s; 2 s; >300 s >300 s >300 s delamination delamination

[0124] The test methods for the above characteristics are as follows.

[0125] 1) Glass transition temperature (Tg): The Tg of the laminate was measured according to the dynamic thermal mechanical analysis (DMA) method specified in IPC-TM-650 2.4.24.4.

[0126] 2) Thermal decomposition temperature (Td-5% loss): According to the thermogravimetric analysis (TGA), the temperature Td at 5% weight loss of the laminate was measured according to the TGA method specified in IPC-TM-650 2.4.24.6.

[0127] 3) PCT water absorption rate: After etching the copper foil on the surface of the copper clad laminate, the substrate was dried to weigh the original weight, and then placed in a pressure cooker, treated at 120 C. and 150 KPa for two hours, taken out with a dry cloth, wiped to dry and to weigh the sample after water absorption. PCT water absorption (weight after cooking-weight before cooking)/weight before cooking.

[0128] 4) Dielectric constant Dk and dielectric loss factor Df: Tested according to the SPDR (Split Post Dielectric Resonator) method at a test frequency of 10 GHz.

[0129] 5) Pendulum impact strength: Using a simple-supported beam non-metallic material pendulum impact tester. A laminate of about 1.6 mm was made into several 120 mm*10 mm notched samples (notch depth 2 mm). The pendulum was used to impact the sample at a speed of 3.8 m/s. After the sample broke, the absorption work of the pendulum impact tester was read. Finally, the pendulum impact strength was calculated.

[0130] 6) Drop hammer impact toughness: using the drop hammer impact tester. The drop hammer of the impact tester had a drop height of 100 cm and a weight of 1 Kg. Toughness evaluation: the clearer the cross was, the better the toughness of the product was, represented by the character 0. If the cross was blurred, it showed that the product had poor toughness and brittleness, which was represented by the character A. If the clarity of the cross was between clarity and blur, it indicated that the product had a general toughness, which was represented by the character 0.

[0131] 7) PCT: After etching the copper foil on the surface of the copper clad plate, the substrate was placed in a pressure cooker, treated at 120 C. and 150 KPa for two hours, and then immersed in a tin furnace at 288 C. When the substrate was layered, the corresponding time was recorded. The evaluation could be ended if bubbles or delamination did not appear after the substrate was in the tin furnace for more than 5 minutes.

[0132] Physical Property Analysis

[0133] It can be seen from the physical property data in Tables 2 and 3 that Comparison Example 1 discloses that the substrate has a higher glass transition temperature, better electrical properties, lower water absorption ratio, but extremely worst toughness after the polyfunctional vinyl aromatic copolymer VOD-A was used for self-curing. In Comparison Example 2, a polyfunctional vinyl aromatic copolymer VOD-C was used. Based on the total amount of the structural units represented by the general formula (a.sub.1) and (a.sub.2) in the copolymer, the molar fraction of the structural unit represented by the general formula (a.sub.1) was 0.25, i.e. (a.sub.1)/[(a.sub.1)+(a.sub.2)]=0.25. At this time, the heat resistance of the substrate was reduced, and the toughness thereof was poor. In Comparison Example 3, after the addition of the hydrogenated styrene butadiene block copolymer, the toughness of the substrate was improved, but the glass transition temperature was significantly reduced. Moreover, the delamination and plate blasting appeared, and it had a poor heat and humidity resistance. In Comparison Example 4, the terminal (meth)acryloyl cage-type silsesquioxane A was introduced as a crosslinking agent. It was inferior in dielectric properties due to its high polarity. In Comparison Example 5, the styrene content in the styrene-butadiene copolymer used was higher than 50%, which caused the toughness of the substrate to be significantly reduced. In Comparison Example 6, maleated polybutadiene Ricon 130MA8 was used. Since such polyolefin resin had a polar structure, it made the dielectric properties of the prepared substrate worse, and reduced the toughness.

[0134] In Examples 1 to 8, the olefin resin (styrene-butadiene copolymer) was used as the polyfunctional vinyl aromatic copolymer VOD-A/VOD-B. The cured substrate had good toughness and maintained its high glass transition temperature, low water absorption, excellent dielectric properties and heat and humidity resistance.

[0135] As described above, the circuit substrate of the present invention has good toughness as compared with general laminates, and maintains its high glass transition temperature, low water absorption, excellent dielectric properties, and moist heat resistance.

[0136] The applicant claims that the thermosetting resin composition of the present invention, prepregs and metal foil-clad laminate prepared therefrom are described by the above embodiments. However, the present invention is not limited to the above embodiments, i.e. it does not mean that the present invention cannot be carried out unless the above embodiments are applied. Those skilled in the art shall know that any modifications of the present invention, equivalent substitutions of the materials selected for use in the present invention, and addition of the auxiliary ingredients, and specific manner in which they are selected, all are within the protection scope and disclosure of the present invention.