JPH07157540A - Thermosetting resin composition having low dielectric constant - Google Patents

Abstract

PURPOSE:To obtain the subject composition comprising a specific epoxy resin and a phenolic compound in specified amounts, respectively, low in dielectric dissipation factor, excellent in metal adhesivity and heat resistance, and useful for printed circuit boards, copper-clad laminates, etc. CONSTITUTION:This composition comprises (A) 100 pts.wt. of an epoxy resin consisting mainly of an epoxy resin of formula I [R1, R2 are each an alkyl; X is an alkylene or group of formula II (R3-R6 each is an alkyl); (k) is 0-100], and (B) 20-150 pts.wt. of a phenolic compound of formula III (n>=1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition having a low dielectric constant, a low dielectric loss tangent and a high heat resistance and excellent adhesion to a metal, such as a laminated plate and a metal foil-clad laminated plate. It is preferably used for.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a laminated wiring board resin having excellent heat resistance and low dielectric constant and low dielectric loss tangent for printed wiring used in a high frequency range. On the other hand, a thermoplastic resin such as a fluororesin or a polyphenylene ether resin having a small dielectric constant has been proposed, but it has 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 epoxy resin has a high dielectric constant, and satisfactory characteristics have not been obtained.

Further, the polybutadiene resin containing thermosetting 1,2-polybutadiene as a main component has a low dielectric constant,
The adhesion was poor and the heat resistance was insufficient. A composition containing 5 to 20 parts by weight of 1,2-polybutadiene resin, 5 to 10 parts by weight of a crosslinkable monomer and 100 parts by weight of a polyphenylene ether resin, and a radical crosslinking agent (JP-A-61-8).
3224) is known, but it has a molecular weight of several thousand.
When the 1,2-polybutadiene resin is used, stickiness remains when the solvent is removed from the composition, and the prepreg obtained by coating and impregnating the glass substrate cannot maintain a tack-free state, which is a practical problem. was there. On the other hand, there is a method of using a high molecular weight 1,2-polybutadiene to eliminate stickiness, but this method causes a problem in practical use because the solubility in a solvent is lowered, the solution becomes highly viscous and the fluidity is lowered. It was

[0004]

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

[0005]

That is, the present invention provides an epoxy resin (A) containing an epoxy compound represented by the following general formula [1] as a main component and a phenol compound (B) represented by the general formula [2]. The epoxy resin (A) is 100 parts by weight, and the phenol compound (B) is 50 to 150 parts by weight.

[0006]

[Chemical 1] Here, k represents an integer of 0 or 100 or less. R ₁ , R
₂ represents an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a tertiary butyl group, which may be the same or different. X is a methylene group, an ethylene group,
Alkylene groups such as isopropylidene group, isobutylene group, hexafluoroisopropylidene group or

[Chemical 2] (R ₃ , R ₄ , R ₅ and R ₆ represent an alkyl group having 1 or more carbon atoms and may be the same or different.)
Indicates.

[0007]

[Chemical 3] n represents an integer of 1 or more.

[0008]

The epoxy resin used in the present invention is mainly composed of the epoxy compound represented by the general formula [1]. It is possible to increase the molecular volume by introducing a bulky alkyl substituent or the like into the aromatic ring in the molecule or its connecting part, and as a result, the dielectric constant is smaller than that of a normal bisphenol A type epoxy resin. It is possible to do so, which is preferable. Further, k in the general formula [1] is 1
It is preferably 00 or less. A polymer having a high molecular weight of more than 100 is not preferable because it lowers the workability in the process of manufacturing a laminate. Further, the epoxy resin of the present invention preferably has a halogen substituent corresponding to 15 to 40% by weight of the total amount. If it is less than 15% by weight, flame retardancy cannot be obtained, which is not preferable, and if it exceeds 40% by weight, heat resistance is impaired, which is not preferable. The halogen substituent is not particularly limited, but examples thereof include bromine and chlorine. Further, a flame retardant aid may be added if necessary.

The phenol compound used in the present invention is represented by the general formula [2], but since it has a phenolic hydroxyl group in the molecule, it functions as a curing agent for the epoxy resin. Further, since the molecular skeleton has an aliphatic cyclized structure, it also has a function of lowering the values of the dielectric constant and the dielectric loss tangent, which is preferable. The hydroxyl equivalent of this phenol compound is preferably 100 to 2000. 10
If it is less than 0, the effect of improving the dielectric properties will be weakened, and if it exceeds 2000, the crosslinking density will decrease as an epoxy curing agent, and sufficient heat resistance will not be obtained, such being undesirable. Specific examples of the phenol compound used in the present invention include special phenol resins DPP-600L, DPP-600M and DPP-600 manufactured by Nippon Oil Co., Ltd.
H, etc., but is not particularly limited thereto. Further, a part of other epoxy curing agent may be used in combination as long as it does not adversely affect.

The low dielectric constant thermosetting resin composition of the present invention comprises a specific epoxy resin (A) and a phenol compound (B), and the ratio thereof is 100 parts by weight of the epoxy resin (A). Phenol compound (B) 2
It is desirable that the amount is 0 to 150 parts by weight. When the amount of the phenol compound (B) is less than 20 parts by weight, the effect of lowering the dielectric constant is insufficient, and when it exceeds 150 parts by weight, the heat resistance is lowered, which is not preferable. The thermosetting resin composition of the present invention contains a specific epoxy resin and a phenol compound, but a curing accelerator can be used to adjust the curing rate. As a curing accelerator,
Imidazole compounds, organic phosphorus compounds, tertiary amines,
A quaternary ammonium salt or the like is used. It is possible to use several kinds of these accelerators in combination. The blending amount is preferably 0.01 to 5% by weight with respect to the epoxy resin.
If it is less than 0.01% by weight, the promoting effect is small, and if it exceeds 5% by weight, the storage stability is lowered.

The epoxy resin composition of the present invention can be used in various forms, but a solvent is usually used when coating and impregnating a substrate. It is necessary that the solvent used has good solubility in part or all of the composition, but a poor solvent can be used as long as it does not adversely affect the composition. Examples of the solvent used include acetone, methyl ethyl ketone, methyl isobutyl ketone, ketone solvents such as cyclohexanone, aromatic hydrocarbon solvents such as toluene, xylene, mesitylene, methyl cellosolve, ethyl cellosolve butyl alsolve, isobutyl. Cellsolve, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether Various glycol ether solvents such as butyl ether, methyl cell Ester solvent such as rubu acetate, ethyl cellosolve acetate, butyl cellosolve acetate, ethyl acetate, dialkyl glycol ether solvent such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, N, N-dimethyl There are amide solvents such as acetamide, N, N-dimethylformamide and N-methyl-2-pyrrolidone, and alcohol solvents such as methanol and ethanol, and these may be used in combination.

The varnish obtained by using the above-mentioned solvent with the epoxy resin composition of the present invention 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, and dried in a drying oven. A prepreg for a printed wiring board can be obtained by drying in the 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 metal, and high heat resistance. It is a thermosetting resin and is preferably used for laminated plates, metal-clad laminated plates and the like.

[0013]

EXAMPLES The present invention will now be described in more detail with reference to examples. << Example 1 >> 66 parts of an epoxy compound represented by the following formula [3] having an epoxy equivalent of 300 (parts by weight, the same applies hereinafter)

[Chemical 4]

To 34 parts of tetrabromobisphenol A was added and heated and stirred at 120 ° C., and 0.01 part of 2-methylimidazole was further added and 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-1). Phenolic resin DPP-600 manufactured by Nippon Oil Co., Ltd. having an OH equivalent of 173 relative to 100 parts of resin (A-1).
43.25 parts of M was added to the resin (A-1) in an equivalent ratio (moles of epoxy groups / moles of hydroxyl groups) of 1, and cured to a total of 100 parts of both solid contents. Accelerator 2-Ethyl-4-methylimidazole (0.8 parts) was added, and the varnish solution was adjusted with toluene so that the non-volatile content was 50%.

Then, using this varnish, 100 parts of glass cloth (thickness 0.18 mm, E-glass manufactured by Nitto Boseki Co., Ltd.) was impregnated with 43 parts of the varnish with a solid content and dried in a drying oven at 150 ° C. for 4 minutes. It was dried to prepare a prepreg. The obtained prepreg was tack-free and had excellent workability. Eight sheets of the above-mentioned dried prepregs were stacked, and electrolytic copper foils having a thickness of 35 μm were stacked on top and bottom, and heat and pressure molding was performed 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 It was
After removing the surface of the laminated plate by etching, the laminate was treated for 20 hours at 121 ° C. under a pressure cooker condition of 2.0 atm, and the weight increase was measured. The results are shown in Table 2.

The measurement of the dielectric constant and the dielectric loss tangent is JIS C
According to 6481, the capacitance at a frequency of 1 MHz was measured and determined. JIS C 6 for solder heat resistance and peel strength
The solder heat resistance was measured at 260 ° C. for 300 seconds, and the appearance was checked for abnormality. The flame retardancy was evaluated by the vertical method according to UL-94 standard. The glass transition temperature was determined from the peak temperature of tan δ by the viscoelastic method. The results are shown together in Table 2.

Example 2 To 66 parts of an epoxy compound represented by the following formula [4] having an epoxy equivalent of 250

[Chemical 5]

34 parts of tetrabromobisphenol A was added and reacted under the same conditions as in Example 1 to give an epoxy equivalent of 2
A solid epoxy resin having a bromine content of 75 and a bromine content of 20% was obtained. Hereinafter, this is abbreviated as resin (A-2). Resin (A-
2) DPP-60 used in Example 1 for 100 parts
62.91 parts of 0M was added, and a laminated plate was manufactured in the same manner as in Example 1 below, and various characteristics were evaluated. The results are shown in Table 2.

<< Examples 3 to 6 and Comparative Examples 1 to 6 >> Laminated plates were produced in the same manner as in Example 1 except for the compounding recipe shown in Table 1, and the results are shown in Table 2. .

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

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, an excellent adhesion to a metal, and a thermosetting property. It is a resin composition. Therefore, it is an optimal 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 laminate resin, which is an industrial advantage. Is large.

Claims (3)

[Claims] 1. An epoxy resin (A) containing an epoxy compound represented by the following general formula [1] as a main component and a phenol compound (B) represented by the following general formula [2], each of which is an epoxy resin. (A) 100 parts by weight Phenol compound (B) 20 to 150 parts by weight A low dielectric constant thermosetting resin composition characterized by the above. [Chemical 1] Here, k represents an integer of 0 or 100 or less. R ₁ , R
₂ represents an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a tertiary butyl group, which may be the same or different. X is a methylene group, an ethylene group,
Alkylene groups such as isopropylidene group, isobutylene group, hexafluoroisopropylidene group or (R ₃ , R ₄ , R ₅ and R ₆ represent an alkyl group having 1 or more carbon atoms and may be the same or different from each other). [Chemical 3] n represents an integer of 1 or more. 2. The resin composition according to claim 1, wherein the epoxy resin (A) has 15 to 40% by weight of the total amount of halogen substituents. 3. The resin composition according to claim 1, wherein the hydroxyl equivalent of the phenol compound (B) is 100 to 2000.