JP2680506B2 - Low dielectric constant thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high heat-resistant thermosetting resin composition having a low dielectric constant, a low dielectric loss tangent, and excellent adhesion to metals. It is preferably used for

[0002]

2. Description of the Related Art In recent years, there has been a demand for a resin for a laminate having excellent heat resistance and a low dielectric constant and a low dielectric loss tangent for a printed wiring used in a high frequency range. On the other hand, thermoplastic resins such as fluororesins and polyphenylene ether resins having a small dielectric constant have been proposed, but have problems such as poor workability and adhesiveness and lack of reliability. Therefore, an epoxy-modified polyphenylene ether resin or a polyphenylene ether-modified epoxy resin has been proposed for the purpose of improving workability and adhesiveness. However, the dielectric constant of the epoxy resin is high and satisfactory characteristics have not been obtained. A curable resin composition obtained by blending a polyphenylene ether resin and a polyfunctional cyanate ester resin, and further mixing other resins, adding a radical polymerization initiator, and performing a preliminary reaction (Japanese Patent Application Laid-Open No. S57-18535).
No. 0) is known, but the decrease in the dielectric constant was insufficient.

A polybutadiene resin containing thermosetting 1,2-polybutadiene as a main component has a low dielectric constant.
The adhesiveness was poor and the heat resistance was insufficient. Composition containing 5 to 20 parts by weight of a 1,2-polybutadiene resin, 5 to 10 parts by weight of a crosslinkable monomer and a radical crosslinking agent per 100 parts by weight of a polyphenylene ether resin (JP-A-61-8)
However, when a 1,2-polybutadiene resin having a molecular weight of several thousand is used, stickiness remains when the solvent is removed from the composition, and the composition is coated and impregnated on a glass substrate or the like. There is a practical problem since the obtained prepreg cannot maintain a tack-free state. On the other hand, in order to eliminate stickiness, there is a method using 1,2-polybutadiene having a high molecular weight. However, according to this method, the solubility in a solvent is reduced, the solution becomes high in viscosity, and the fluidity is reduced, which is a practical problem. Was.

[0004]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies to obtain a thermosetting resin having low dielectric constant, high heat resistance, high adhesiveness and excellent workability. .

[0005]

That is, according to the present invention, the area ratio of an aliphatic proton to an aromatic proton in a proton NMR spectrum is 9 in which two or more epoxy groups are contained in the molecule.
Epoxy resin (A) of 5/5 to 80/20 and phenol compound (B) represented by the following general formula [I]

[0006]

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A low dielectric constant thermosetting resin composition characterized by containing and.

[0008]

The epoxy resin used in the present invention has at least two epoxy groups in the molecule and has an area ratio of aliphatic protons to aromatic protons in the proton NMR spectrum of 95/5 to 80/20. . An epoxy compound containing only one epoxy group in the molecule is not preferable because the curability is insufficient and only a cured product having low heat resistance can be obtained. The area ratio of aliphatic protons to aromatic protons in the proton NMR spectrum is 95/5 to 80/2.
It is desirable to be in the range of 0. If the aliphatic protons are larger than 95/5 with respect to the aromatic protons, the heat resistance of the cured product decreases, which is not preferable. On the other hand, if it is smaller than 80/20, the heat resistance of the cured product is excellent, but the dielectric constant and dielectric loss tangent of the resulting cured product are undesirably large. As a desirable epoxy resin

[0009]

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An epoxy resin or an alicyclic epoxy resin having a bulky alkyl substituent such as

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A preferable example is a combination of epoxy resins having an equivalent halogen substituent, but the combination is not particularly limited. The epoxy resin of the present invention preferably has a halogen substituent equivalent to 15 to 40% by weight of the total amount. If it is less than 15% by weight, sufficient flame retardancy cannot be obtained, which is not preferable, and if it exceeds 40% by weight, heat resistance is impaired. The halogen substituent is not particularly limited, and examples thereof include bromine and chlorine. Further, a flame retardant aid can be added as needed. The phenol compound used in the present invention is represented by the general formula [I], but since it has a phenolic hydroxyl group in the molecule, it can function as a curing agent for the epoxy resin. Further, since the molecular skeleton has a cyclized structure, it has a function of lowering the values of the dielectric constant and the dielectric loss tangent. Although the epoxy resin composition of the present invention contains a specific epoxy resin and a phenol compound, a curing accelerator can be used to adjust the curing speed. As the curing accelerator, an imidazole compound, an organic phosphorus compound, a tertiary amine, a quaternary ammonium salt, or the like is used. Some of these accelerators can be used in combination. The compounding amount is preferably 0.01 to 5% by weight based on the epoxy resin. 0.
If it is less than 01% by weight, the promoting effect is small, and if it exceeds 5% by weight, the storage stability is lowered.

Although the epoxy resin composition of the present invention is used in various forms, a solvent is often used when coating and impregnating a substrate. The solvent used is required to show good solubility in part or all of the composition,
A poor solvent can be used as long as no adverse effect is exerted. Examples of solvents used include acetone, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone, aromatic hydrocarbon solvents such as toluene, xylene and mesitylene, methyl cellosolve, ethyl cellosolve butyl alsolve, and isobutyl. Cellosolve, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene ghoul monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether,
Various glycol ether solvents such as ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, etc .; ester solvents such as methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, and ethyl acetate; ethylene glycol dimethyl ether; diethylene Gutacol dimethyl ether,
Dialkyl glycol ether solvents such as diethylene glycol diethyl ether and diethylene glycol dibutyl ether, N, N-dimethylacetamide, N, N
There are amide solvents such as -dimethylformamide and N-methyl-2-pyrrolidone, and alcohol solvents such as methanol and ethanol, and some of these can be used in combination.

The varnish obtained by dissolving the epoxy resin composition of the present invention in the above solvent is applied to and impregnated into a base material such as glass woven cloth, glass non-woven cloth or paper, or cloth having a component other than glass as a drying oven. A prepreg for a printed wiring board can be obtained by drying in the temperature range of 80 to 200 ° C. The prepreg is used for producing a printed wiring board by heating and pressurizing, but the epoxy resin composition of the present invention has a low dielectric constant, a low dielectric loss tangent, excellent workability, excellent adhesiveness to a metal, and high heat resistance. It is a thermosetting resin,
It is preferably used for laminated plates, metal-clad laminated plates and the like.

[0014]

The present invention will be described in more detail with reference to the following examples. << Example 1 >> 66 parts of an epoxy compound represented by the following formula having an epoxy equivalent of 300 (parts by weight, the same applies hereinafter)

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34 parts of tetrabromobisphenol A was added thereto, and the mixture was heated and stirred at 120 ° C., and 0.01 parts of 2-methylimidazole was further added. The mixture was reacted at 150 ° C. for 4 hours.
A solid epoxy resin having an epoxy equivalent of 400 and a bromine content of 20% was obtained. Hereinafter, this is abbreviated as resin (A). The result of measurement of the proton NMR spectrum of the resin (A) is shown in FIG. The area ratio of the aliphatic protons to the aromatic protons was determined by this, and was 85/15.
OH equivalent of 16 represented by the general formula [I] with respect to the resin (A)
9 Nippon Oil Co., Ltd. phenol resin DPP
600M was added to the resin (A) in an equivalent ratio (epoxy group mole number / hydroxyl group mole number) of 1, and 0.8 part of the curing accelerator was added to 100 parts of the total solid content of both. , 2-ethyl-4-methylimidazole were added, and the varnish solution was adjusted with methyl ethyl ketone to a non-volatile content concentration of 55%. Then, using this varnish, a glass cloth (thickness 0.18 mm, E-glass manufactured by Nitto Boseki Co., Ltd.) 10
The prepreg was prepared by impregnating 0 parts of the varnish with 43 parts of the solid content and drying it in a drying oven at 150 ° C. for 4 minutes. The obtained prepreg was tack-free and excellent in workability.
Eight sheets of the above-mentioned dried prepreg were piled up, 35 μm thick electrolytic copper foils were piled up and down, and heat and pressure molding was carried out at a pressure of 40 kgf / cm ² and a temperature of 175 ° C. for 1 hour to obtain a laminated plate having a thickness of 1.6 mm. After removing the surface of the laminate by etching, 121
2 under pressure cooker condition of pressure of 2.0 atm at ℃
The mixture was treated for 0 hour and the weight increase was measured. Table 2 shows the results.

The measurement of dielectric constant and dielectric loss tangent is based on JIS
It was determined according to C6481 by measuring the capacitance at a frequency of 1 MHz. Solder heat resistance and peel strength were also measured according to JIS C 6481.
The presence or absence of abnormal appearance was examined at 0 ° C. for 300 seconds. Flame retardancy was evaluated by the vertical method according to the UL-94 standard. The glass transition temperature was determined from the peak temperature of tan δ by the viscoelastic method. The results are shown in Table 2. << Examples 2 and 3 and Comparative Examples 1 to 3 >> As shown in Table 1, laminated plates were prepared in the same manner as in Examples except for the composition of each epoxy resin and the curing agent, and various characteristics were evaluated. Table 2 shows the results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

As is clear from the results shown in Tables 1 and 2, the epoxy resin composition of the present invention has a low dielectric constant, a low dielectric loss tangent, and excellent thermosetting properties with excellent adhesion to metal and excellent heat resistance. It is a resin composition. Therefore, it is the most suitable resin for printed wiring boards that require low dielectric constant and low dielectric loss tangent, and copper-clad laminates can be manufactured in the same process as conventional resin for laminates, which is an industrial advantage. Is big.

[Brief description of the drawings]

FIG. 1 is a proton NMR spectrum of resin (A).

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-320315 (JP, A) JP-A-5-320314 (JP, A) JP-A-5-222156 (JP, A) JP-A-3- 47826 (JP, A)

Claims (2)

(57) [Claims] 1. An epoxy resin (A) containing two or more epoxy groups in the molecule and having an area ratio of an aliphatic proton to an aromatic proton in a proton NMR spectrum of 95/5 to 80/20, and the following general formula: Phenol compound (B) represented by [I] A low dielectric constant thermosetting resin composition comprising: 2. Epoxy resin is 15 to 4 out of the total amount.
2. The resin composition according to claim 1, having 0% by weight of a halogen substituent.