JP4783988B2 - Heat resistant resin composition, prepreg and laminate using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resin composition, a prepreg, and a laminate having excellent heat resistance and excellent dielectric properties. In particular, it is suitably used for high frequency circuit boards.
[0002]
Information processing devices such as notebook personal computers and mobile phones are required to be downsized. There is an increasing demand for reduction in size and weight in printed wiring boards on which electronic components such as LSIs are mounted. In order to reduce the size and weight, it is necessary to reduce the wiring width, reduce the through-hole diameter, and reduce the plating thickness. If the plating thickness is reduced, plating cracks may occur during thermal shock, and heat resistance is required. At the same time, speeding up of these information processing crises is also demanded, and the CPU clock frequency is increasing. For this reason, it is required to increase the signal propagation speed, and it is necessary that the printed board has a low dielectric constant and low dielectric loss tangent, which is advantageous for increasing the speed.
[0003]
A cyanate resin is used as a resin having excellent heat resistance and excellent dielectric properties (for example, JP-A-8-8501). Since the cyanate resin does not generate a highly polar reactive group such as a hydroxyl group by the curing reaction, it has excellent dielectric characteristics. However, since it contains a lot of nitrogen atoms, it has a drawback of high water absorption.
[0004]
[Problems to be solved by the invention]
The present invention has been made as a result of studies to solve such problems. By using a cyanate resin and an epoxy-modified polybutadiene resin in combination, a resin composition, a prepreg, and a prepreg excellent in heat resistance, dielectric properties, and water absorption. The laminated board obtained from is provided.
[0005]
[Means for Solving the Problems]
The present invention relates to (A) a cyanate resin represented by the following general formula (1) or a prepolymer thereof, and
(B) A heat-resistant resin composition comprising an epoxy-modified polybutadiene resin represented by the following general formula (2) as an essential component. And this invention is a prepreg characterized by making a base material impregnate the said heat resistant resin composition, Furthermore, 1 or 2 or more sheets of the said prepreg are overlap | superposed and heat-pressed. copper-clad laminate characterized.
[Formula 4]
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The (A) component cyanate resin used in the present invention is represented by the following general formula (1).
Moreover, what prepolymerized cyanate resin which has this general formula is preferably used in order to adjust a moldability and fluidity | liquidity, and is contained in (A) component of this invention. The prepolymerization is usually performed by heating and melting. In the present invention, the prepolymer means a trimerization rate of 20 to 50%. The trimerization rate can also be determined using an infrared spectroscopic analyzer.
As for cyanate resin, 40-80 weight part is preferable in 100 weight part of resin components. If it is less than 40 parts by weight, the solder heat resistance at 260 ° C. is not sufficient, and if it exceeds 80 parts by weight, the water absorption rate is deteriorated.
The alkyl group of R1 of the cyanate resin in the present invention preferably has 1 to 6 carbon atoms, and the aryl group preferably has 2 to 6 carbon atoms. Similarly, the alkyl group of R2 preferably has 1 to 4 carbon atoms, and the aryl group preferably has 1 to 3 carbon atoms.
[Chemical formula 5]
[0007]
The epoxy-modified polybutadiene resin (B) used in the present invention is represented by the following general formula (2).
[Chemical 6]
The epoxy-modified polybutadiene resin is preferably 10 to 40 parts by weight in 100 parts by weight of the resin component. If it is less than 10 parts by weight, the water absorption is not sufficiently reduced. If it exceeds 40 parts by weight, the solder heat resistance at 260 ° C. is deteriorated, which is not preferable.
The molecular weight of the epoxy-modified polybutadiene resin is preferably 700 to 10,000, and preferably 1,000 to 3,000 from the viewpoint of impregnation with the substrate.
As described above, the cyanate resin generates a triazine ring by a curing reaction. However, since the triazine ring is excellent in symmetry, the polarization is small and the dielectric property is very excellent. However, since cyanate resin has a high nitrogen content, it has a drawback of high water absorption. In the present invention, an epoxy-modified polybutadiene resin is used in combination to solve this problem. Epoxy-modified polybutadiene resin does not have a substituent having a large polarity such as a hydroxyl group in the molecule, and therefore has excellent dielectric properties and low water absorption. Further, since the epoxy group reacts with the cyanate group, it can be incorporated into the resin skeleton, so that the excellent 260 ° C. solder heat resistance of the cyanate resin is not lowered.
[0008]
Examples of the substrate used in the present invention include glass fabric, glass fabric, and fabric or fabric containing components other than glass. Among these base materials, a glass woven fabric is preferable in terms of strength and water absorption.
[0009]
For the method of impregnating the substrate with the resin composition obtained in the present invention, an impregnation coating facility or the like is used.
In the present invention, when impregnating the base material, it is usually preferable from the viewpoint of impregnation to use it in the form of a varnish dissolved in a solvent. The solvent used preferably has good solubility in the composition, but a poor solvent may be used as long as it does not adversely affect the composition. Examples of the solvent exhibiting good solubility include methyl ethyl ketone and cyclohexanone.
A prepreg can be obtained by impregnating a base material with a varnish obtained by dissolving the resin composition of the present invention in a solvent and drying at 80 to 200 ° C.
[0010]
One or two or more prepregs obtained in the present invention are overlapped and heated and pressed at 150 to 200 ° C. to obtain a laminate or a copper-clad laminate.
[0011]
The resin composition of the present invention contains the cyanate resin and the epoxy-modified polybutadiene resin described above as essential components, but within a range not contrary to the object of the present invention, other resins, curing accelerators, coupling agents, flame retardants, Other ingredients may be added. When a brominated epoxy resin is used as the flame retardant, the epoxy group and the cyanate group react with each other and the flame retardant can be incorporated into the resin skeleton, which is preferable without deteriorating the properties of the resin. As the curing accelerator, cobalt-containing compounds such as cobalt acetylacetonate and cobalt naphthenate, zinc-containing compounds such as zinc chloride and zinc naphthenate, and copper-containing compounds such as copper chloride are preferable.
[0012]
【Example】
Example 1
70 parts by weight of bisphenol A cyanate resin (prepolymerized, 40% trimerization, B-40 manufactured by Ciba-Geigy), epoxy-modified polybutadiene resin (weight average molecular weight 3000, epoxy equivalent 1400, R-45EPT manufactured by Nagase Chemical Industries) ) Cyclohexanone was added to 30 parts by weight and 0.10 parts by weight of the cobalt acetylacetone complex, and the varnish was adjusted so as to have a nonvolatile content concentration of 55% by weight.
Using this varnish, 100 parts by weight of glass fiber cloth (thickness 0.18 mm, manufactured by Nitto Boseki Co., Ltd.) was impregnated with 80 parts by weight of varnish solids, and dried in a dryer oven at 150 ° C. for 5 minutes to obtain a resin. A prepreg having a content of 44.4% was prepared.
6 sheets of the above prepreg are stacked, and 35 μm thick electrolytic copper foils are stacked on the top and bottom. The pressure is 40 kgf / cm ² , the temperature is 200 ° C. for 120 minutes, and the temperature is 220 ° C. for 60 minutes, and the thickness is 1.2 mm. A double-sided copper-clad laminate was obtained.
[0013]
(Examples 2-3 and Comparative Examples 1-3)
A double-sided copper-clad laminate was prepared in the same manner as in Example 1 except for the formulation shown in Table 1.
[0014]
The obtained copper-clad laminate was measured for flame retardancy, solder heat resistance, peel strength, and water absorption. Solder heat resistance, peel strength, and water absorption are measured according to JIS C 6481. Solder heat resistance is an abnormal appearance after being immersed in a solder bath at 260 ° C. for 120 seconds after performing a moisture absorption treatment for 2 hours after boiling. The presence or absence of was investigated. Flame retardancy was evaluated by a vertical method using a 1 mm thick sample in accordance with UL-94 standards. The glass transition point was measured using RDS-7700 manufactured by Rheometrics at a heating rate of 3 ° C./min and a frequency of 1 Hz. The dielectric constant and dielectric loss tangent were measured according to JIS C 6481 and measured by measuring the capacitance at a frequency of 1 MHz. The evaluation results are shown in Table 1. It can be seen that the copper-clad laminates shown in the examples all have low dielectric constant and dielectric loss tangent, and are excellent in heat resistance, solder heat resistance, and water absorption.
[0015]
[Table 1]
[0016]
[Table 2]
[0017]
Notes to the table (1) Bisphenol A cyanate (prepolymerization: trimerization rate 40%, trade name: B-40 manufactured by Ciba Geigy)
(2) Epoxy-modified polybutadiene (molecular weight 3000, epoxy equivalent 1400, trade name: R-45EPT manufactured by Nagase Chemical Industries)
(3) Brominated epoxy resin (epoxy equivalent 400, bromination rate 48%, Epicron 153 manufactured by Dainippon Ink & Chemicals, Inc.)
(4) Cobalt acetylacetonate (5) Polybutadiene (Molecular weight 3000, Nippon Petrochemical Co., Ltd. B-3000)
[0018]
【The invention's effect】
When applied to a printed wiring board material, the heat resistant resin composition of the present invention has high heat resistance, low dielectric constant, and excellent water absorption. Accordingly, in the future, the present invention will provide a resin composition optimum for a printed wiring board in a crisis for small information processing.

Claims (3)

(A) a cyanate resin represented by the following general formula (1) or a prepolymer thereof, and
R ¹ is alkylene group, arylene group ^R 2, ^{R 3,} is -H, an alkyl group, containing epoxy-modified polybutadiene resin represented by an aryl group (B) represented by the following general formula (2), as essential components A heat-resistant resin composition characterized by comprising:
A prepreg obtained by impregnating a base material with the resin composition according to claim 1. CCL characterized by comprising heating and pressing superposed claim 2 prepreg according to one or two or more.