Resin composition, prepreg, metal foil-clad laminate, resin sheet, and printed circuit board

Abstract

A resin composition according to the present invention contains a cyanate compound (A). Further, the resin composition according to the present invention contains a maleimide compound (B) and/or an epoxy resin (C); and primary hexagonal boron nitride particles (D) having an average aspect ratio of 4 to 10.

Claims

1. A resin composition comprising: a cyanate compound (A); a maleimide compound (B); an epoxy resin (C); primary hexagonal boron nitride particles (D) having an average aspect ratio of 4 to 10; and a second boron nitride other than the primary hexagonal boron nitride particles (D), and optionally comprising an inorganic filler other than the primary hexagonal boron nitride particles (D) and the second boron nitride, wherein the cyanate compound (A) comprises a naphthol aralkyl-based cyanate compound represented by the following formula (A-1), ##STR00013## wherein R1 each independently represents a hydrogen atom or a methyl group, and n1 represents an integer of 1 to 50, the maleimide compound (B) comprises bis(3-ethyl-5-methyl-4-maleimidophenyl)methane and a maleimide compound represented by the following formula (B-1), ##STR00014## wherein R.sub.5 each independently represents a hydrogen atom or a methyl group, and n.sub.1 represents an integer of 1 or more, the epoxy resin (C) comprises a polyoxynaphthylene-based epoxy resin and a trisphenol-based epoxy resin, a content of the cyanate compound (A) is 10 to 80 parts by mass based on 100 parts by mass of the resin solid component, a content of the maleimide compound (B) is 10 to 80 parts by mass based on 100 parts by mass of the resin solid component, a content of the epoxy resin (C) is 3 to 80 parts by mass based on 100 parts by mass of the resin solid component, and a content of the primary hexagonal boron nitride particles (D) is 50 parts by mass or more based on 100 parts by mass of the resin solid component, provided that a total amount of the primary hexagonal boron nitride particles (D), the second boron nitride, and the inorganic filler is 301 parts by mass or less based on 100 parts by mass of the resin solid component.

2. The resin composition according to claim 1, wherein the cyanate compound (A) further comprises at least one selected from a group consisting of a phenol novolac-based cyanate compound and a biphenyl aralkyl-based cyanate compound represented by the following formula (A-2), ##STR00015## wherein R3 each independently represents a hydrogen atom or a methyl group, and n3 represents an integer of 1 to 50.

3. The resin composition according to claim 1, wherein the epoxy resin (C) further comprises at least one selected from a group consisting of a biphenyl aralkyl-based epoxy resin, a naphthylene ether-based epoxy resin, a polyfunctional phenol-based epoxy resin, and a naphthalene-based epoxy resin.

4. The resin composition according to claim 1, further comprising at least one selected from a group consisting of a phenolic resin, an oxetane resin, a benzoxazine compound, and a compound having a polymerizable unsaturated group.

5. The resin composition according to claim 1, wherein the maleimide compound (B) further comprises at least one selected from a group consisting of 2,2′-bis{4-(4-maleimidophenoxy)-phenyl}propane and a maleimide compound represented by the following formula (B-2), ##STR00016## wherein a plurality of R each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and n is an average value and represents 1<n≤5.

6. The resin composition according to claim 5, wherein the maleimide compound (B) further comprises a maleimide compound represented by the following formula (B-2), ##STR00017## wherein a plurality of R each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and n is an average value and represents 1<n≤5.

7. The resin composition according to claim 1, wherein an epoxy equivalent weight of the epoxy resin (C) is 250 to 850 g/eq.

8. The resin composition according to claim 7, wherein an epoxy equivalent weight of the epoxy resin (C) is 250 to 450 g/eq.

9. A prepreg comprising: a base material; and the resin composition according to claim 1, with which the base material is impregnated or coated.

10. A metal foil-clad laminate comprising: at least one or more of the prepregs according to claim 9 laminated; and a metal foil disposed on one surface or both surfaces of the prepreg.

11. A resin sheet comprising: a support; and the resin composition according to claim 1, disposed on a surface of the support.

12. A printed circuit board comprising: an insulating layer; and a conductor layer formed on a surface of the insulating layer, wherein the insulating layer comprises the resin composition according to claim 1.

Description

EXAMPLES

(1) The present embodiment will be more specifically described below using an Example and a Comparative Example. The present embodiment is not limited in any way by the following Example.

(Synthesis Example 1) Synthesis of 1-Naphthol Aralkyl-Based Cyanate Resin (SNCN)

(2) 300 g (1.28 mol in terms of OH groups) of an α-naphthol aralkyl resin (SN495V, OH group equivalent: 236 g/eq., manufactured by Nippon Steel Chemical Co., Ltd.) and 194.6 g (1.92 mol) (1.5 mol based on 1 mol of hydroxy groups) of triethylamine were dissolved in 1800 g of dichloromethane in a reactor, and this solution was a solution 1.

(3) While 125.9 g (2.05 mol) (1.6 mol based on 1 mol of hydroxy groups) of cyanogen chloride, 293.8 g of dichloromethane, 194.5 g (1.92 mol) (1.5 mol based on 1 mol of hydroxy groups) of 36% hydrochloric acid, and 1205.9 g of water were kept at a liquid temperature of −2 to −0.5° C. under stirring, the solution 1 was poured over 30 minutes. After completion of pouring of the solution 1, the mixture was stirred at the same temperature for 30 minutes, and then a solution of 65 g (0.64 mol) (0.5 mol based on 1 mol of hydroxy groups) of triethylamine dissolved in 65 g of dichloromethane (solution 2) was poured over 10 minutes. After completion of pouring of the solution 2, the mixture was stirred at the same temperature for 30 minutes to complete the reaction.

(4) Then, the reaction liquid was allowed to stand to separate the organic phase and the aqueous phase. The obtained organic phase was washed five times with 1300 g of water. The electrical conductivity of the wastewater from the fifth water washing was 5 μS/cm, and it was confirmed that removable ionic compounds were sufficiently removed by the washing with water.

(5) The organic phase after the water washing was concentrated under reduced pressure and finally concentrated to dryness at 90° C. for 1 hour to obtain 331 g of the target naphthol aralkyl-based cyanate compound (SNCN) (orange viscous material). The mass average molecular weight Mw of the obtained SNCN was 600. In addition, the infrared absorption spectrum of SNCN showed absorption at 2250 cm.sup.−1 (cyanate groups) and showed no absorption of hydroxy groups.

(6) (Method for Measuring Average Aspect Ratio)

(7) The average aspect ratio was measured based on an image obtained by observing primary hexagonal boron nitride particles using an scanning electron microscope (SEM). In other words, the lengths of the major axis and the minor axis were measured for 50 primary hexagonal boron nitride particles present in a predetermined field of view, and the average aspect ratio was calculated as the average value of major axis/minor axis.

Example 1

(8) 30 parts by mass of the SNCN (cyanate equivalent: 256 g/eq.) obtained by Synthesis Example 1, as a cyanate compound (A); 15 parts by mass of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane (BMI-70, manufactured by Daiwa Kasei Co., Ltd., maleimide equivalent: 221 g/eq.) and 15 parts by mass of a novolac-based bismaleimide compound (manufactured by Daiwa Kasei Co., Ltd., BMI-2300) as maleimide compounds (B); 35.3 parts by mass of a polyoxynaphthylene-based epoxy resin (“HP6000” manufactured by DIC, epoxy equivalent weight: 169 g/eq.) and 4.7 parts by mass of a trisphenol-based epoxy resin (“EPPN-501HY” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight: 169 g/eq.) as epoxy resins (C); 60 parts by mass of “πBN-S03” (average particle diameter 11 μm) manufactured by Tokuyama Corporation, as primary hexagonal boron nitride particles (D); 5.0 parts by mass of a dispersing agent comprising an acid group (manufactured by BYK Japan KK, “BYK-W903”); 15.0 parts by mass of an epoxy-based silane coupling agent (“Z6040” manufactured by Dow Corning Toray Co., Ltd.); 1.0 part by mass of a dispersing agent (manufactured by BYK Japan KK, “DISPERBYK-161”); 1.0 part by mass of a wetting and dispersing agent 1 (manufactured by BYK Japan KK, “BYK-111”); 0.3 parts by mass of a wetting and dispersing agent 2 (manufactured by BYK Japan KK, “BYK-2009”); 0.50 parts by mass of 2,4,5-triphenylimidazole (manufactured by TOKYO CHEMICAL INDUSTRY CO., LTD., curing accelerator); and 0.01 parts by mass of zinc octylate (manufactured by Nihon Kagaku Sangyo Co., Ltd., trademark NIKKA OCTHIX Zinc) were added, mixed, and diluted with methyl ethyl ketone to obtain a resin varnish. The average aspect ratio of πBN-S03 calculated based on the above-described method was 5.8.

Comparative Example 1

(9) A resin varnish was obtained as in Example 1 except that 60 parts by mass of “RBN” (average particle diameter 2 μm) manufactured by Nissin Refratech Co., LTD. was blended as the primary hexagonal boron nitride particles (D) instead of “πBN-S03”. The average aspect ratio of RBN calculated based on the above-described method was 2.5.

Comparative Example 2

(10) A resin varnish was obtained as in Example 1 except that 60 parts by mass of aggregates obtained by subjecting “BTBN009” manufactured by Ben Tree to aggregation treatment to an average particle diameter of 9 μm was blended as the primary hexagonal boron nitride particles (D) instead of “7πBN-S03”. The average aspect ratio of the BTBN009 aggregates calculated based on the above-described method was 12.1.

(11) [Method for Producing Copper-Clad Laminate]

(12) E-glass clothes having a thickness of 0.1 mm were impregnated and coated with the resin varnishes of Example 1 and Comparative Examples 1 to 2 obtained as described above, and heated and dried at 150° C. for 5 minutes using a dryer (pressure-resistant explosion-proof steam dryer, manufactured by TAKASUGI MFG. Co. Ltd.)), to obtain each prepreg comprising 50% by mass of a resin composition. Two or eight of these prepregs were stacked, and 12 μm thick electrolytic copper foil (3EC-M3-VLP, manufactured by MITSUI MINING & SMELTING CO., LTD.) was disposed on both surfaces. The stack was vacuum-pressed at a pressure of 30 kg/cm.sup.2 and a temperature of 220° C. for 150 minutes to obtain a copper-clad laminate having an insulating layer thickness of 0.2 mm or 0.8 mm. Evaluation of the following characteristics was performed using the obtained copper-clad laminate. The results are shown together in Table 1.

(13) <Methods for Evaluating Characteristics>

(14) (1) Thermal Conductivity

(15) All copper foil on both surfaces of the double-sided copper-clad laminate having an insulating layer thickness of 0.8 mm was removed by etching, and then the resultant was cut out into a test piece (10 mm×10 mm×1 mm thick). For this test piece, the thermal conductivity was measured by a laser flash using a xenon flash analyzer LFA447 thermal conductivity meter manufactured by NETZSCH. The thermal conductivity for the Example and the Comparative Examples was evaluated on a scale of 1 to 3 based on the following criteria: ⊚: more than 1.00 W/mk ◯: 0.75 W/mk or more and 1.00 W/mk or less ×: less than 0.75 W/mk
(2) Copper Foil Peel Strength

(16) The copper foil peel strength was measured three times in accordance with JIS C6481, Test methods of copper-clad laminates for printed circuit boards (see 5.7 Peel Strength), using a test piece (30 mm×150 mm×0.8 mm thick) of the double-sided copper-clad laminate having an insulating layer thickness of 0.8 mm, and the average value of the lower limit values was the measured value.

(17) (3) Moisture Absorption Heat Resistance

(18) All copper foil except half of copper foil on one surface of a double-sided copper-clad laminate (50 mm×50 mm×insulating layer thickness 0.8 mm) was removed by etching to obtain a test piece. The obtained test piece was treated at 121° C. and 2 atmospheres by a pressure cooker tester (manufactured by HIRAYAMA MANUFACTURING CORPORATION, model PC-3) for 5 hours and then immersed in solder at 260° C. for 60 seconds. Each of three samples was subjected to the above test, and the presence or absence of blisters after the immersion was visually observed for each sample. One without abnormality was described as “◯”, and one in which blisters occurred was described as “×”. For example, a case where blisters occurred in all three samples was described as “×××”, and a case where blisters occurred in two of three samples was described as “◯××”.

(19) TABLE-US-00001 TABLE 1 Example Comparative Comparative 1 Example 1 Example 2 Average aspect ratio 5.8 2.5 12.1 (major axis/minor axis) Thermal Z-axis 25 conductivity deg. C. ◯ X ◯ XY-axis 25 deg. C. ⊚ Δ ⊚ Copper foil 0.8 kgf/ peel mmt cm 0.85 0.62 0.35 strength Moisture 5 h ◯◯X XXX XXX absorption heat resistance

(20) This application is based on Japanese Patent Application No. 2017-020525 filed on Feb. 7, 2017, the contents of which are incorporated herein by reference.

INDUSTRIAL APPLICABILITY

(21) The resin composition of the present invention has industrial applicability as materials for a prepreg, a metal foil-clad laminate, a laminated resin sheet, a resin sheet, a printed circuit board, and the like.