JP3290239B2 - 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 a metal. It is suitably used for plates and the like.

[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, 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 prepared 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. 57-185350) ) Is known, but the decrease in the dielectric constant was insufficient.

Further, polybutadiene containing thermosetting 1,2-polybutadiene as a main component has a low dielectric constant, but has poor adhesiveness and insufficient heat resistance. Polyphenylene ether
A composition comprising 5 to 20 parts by weight of 1,2-polybutadiene, 5 to 10 parts by weight of a crosslinkable monomer and a radical crosslinking agent per 100 parts by weight (see JP-A-61-83224) is known. When 1,2-polybutadiene having a molecular weight of several thousand is used, stickiness remains when the solvent is removed from the composition, and the prepreg obtained by coating and impregnating on a glass substrate cannot maintain a tack-free state. Therefore, there was a practical problem. 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 has a high 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]

According to the present invention, there is provided a compound represented by the general formula (1):
And a bismaleimide compound represented by the general formula (2) and / or a prepolymer thereof (b), and a weight ratio of (a) and (b). Is in the range of 1/99 to 99/1, which is a low dielectric constant thermosetting resin composition.

Embedded image (R _{1 to} R ₂₀ represent hydrogen or an alkyl group, and the total number of carbon atoms of R _{1 to} R ₁₀ and the total number of carbon atoms of R _{11 to} R ₂₀ are each 8
that's all)

[0006]

The cyanate ester compound represented by the general formula (1) and / or a prepolymer thereof used in the present invention means an organic compound having two or more cyanate ester groups in a molecule. In the present invention, the polyfunctional cyanate ester itself or a prepolymer derived therefrom can be used. These compounds, if necessary, may be zinc naphthenate, cobalt naphthenate, copper naphthenate, lead naphthenate, zinc octylate,
By using a catalyst such as tin octylate, lead acetylacetonate, dibutyltin maleate or the like, the cyanate ester group can be trimerized and the reaction can be appropriately adjusted to form a prepolymer. The cyanate ester group can form a sym-triazine ring in the molecule by trimerization, and can be finally heat-cured.

The substituent of R _{1 to} R ₁₀ in the formula (1) is
Means hydrogen or an alkyl group. Further, the total number of all carbon atoms of the alkyl substituents of R _{1 to} R ₁₀ is preferably 8 or more. When the number of carbon atoms is 8 or more, the free volume can be increased in the heat-cured structure, and the dielectric constant and the dielectric loss tangent can be reduced. If the total number of carbon atoms is less than 8, the dielectric constant and the dielectric loss tangent are not sufficiently reduced, which is not preferable.

The cyanate ester compound used in the present invention is not particularly limited as long as it is represented by the general formula (1). Specific examples include 2,2-bis (4-cyanate). Phenyl) nonane, 2,2-bis (3-tert-butyl-4-cyanatophenyl) propane, 2,2-bis (3-secondarybutyl-4-cyanatophenyl) propane, 1,1-bis (4 -Cyanatophenyl) decane, 1,1-bis (2-methyl-4-cyanato-5-tert-butylphenyl) -2-methyl-propane, 4,4'-cyclohexylidene-
Bis [2- (1,1-dimethylethyl) cyanatobenzene], 4,
4'-methylene-bis [2,6-bis (1,1-dimethylethyl) cyanatobenzene], 4,4'-methylene-bis [2,6-di-secondary-butylcyanatobenzene], 4,4 '-Cyclohexylidene-bis (2-cyclohexyl-1-cyanatobenzene), 4,4'-methylene-bis (2-nonyl-cyanatobenzene), 4,4'-(1-methylethylidene) bis [ 2,6-bis (1,1-dimethylethyl) cyanatobenzene], 4,4 '-(2-ethylhexylidene) biscyanatobenzene, 4,4'-(1-methylheptylidene) bis Cyanate benzene, 4,4'-cyclohexylidene-bis (3-methyl-cyanatobenzene) and the like.

The bismaleimide compound represented by the general formula (2) and / or a prepolymer thereof used in the present invention is a compound having two or more maleimide groups in a molecule. The bismaleimide compound represented by the general formula (2) is obtained by further dehydrating and ring-closing a bismaleamic acid obtained by reacting maleic anhydride and a diamine. A prepolymer can be obtained by reacting this bismaleimide with a polyfunctional amine or a polyfunctional allylphenol compound at a temperature of 200 ° C. or lower. The bismaleimide and / or its prepolymer obtained in this way has excellent heat resistance, and it is of course possible to use two or more kinds in combination.

The substituents of R _{11 to} R ₂₀ in the formula (2) are
Means hydrogen or an alkyl group. Further, the total number of carbon atoms of the alkyl substituents of R _{11 to} R ₂₀ is preferably 8 or more. When the number of carbon atoms is 8 or more, the free volume can be increased in the heat-cured structure, and the dielectric constant and the dielectric loss tangent can be reduced. If the total number of carbon atoms is less than 8, the dielectric constant and the dielectric loss tangent are not sufficiently reduced, which is not preferable.

The bismaleimide compound used in the present invention is not particularly limited as long as it is represented by the general formula (2). For example, 2,2-bis [4-
(4-maleimidophenoxy) phenyl] nonane, 2,2-bis
[3-tert-butyl-4- (4-maleimidophenoxy) phenyl] propane, 2,2-bis [3-secondary-butyl-4-
(4-maleimidophenoxy) phenyl] propane, 1,1-bis [4- (4-maleimidophenoxy) phenyl] decane, 1,1-
Bis [2-methyl-4- (4-maleimidophenoxy) -5-tert-butylphenyl] -2-methylpropane, 4,4'-cyclohexylidene-bis [1- (4-maleimidophenoxy) -2-
(1,1-dimethylethyl) benzene], 4,4'-methylene-bis
[1- (4-maleimidophenoxy) -2,6-bis (1,1-dimethylethyl) benzene], 4,4'-methylene-bis [1- (4-maleimidophenoxy) -2,6-di- Secondary butylbenzene],
4,4′-cyclohexylidene-bis [1- (4-maleimidophenoxy) -2-cyclohexylbenzene], 4,4′-methylene-bis [1- (maleimidophenoxy) -2-nonylbenzene], 4,
4 '-(1-methylethylidene) -bis [1- (maleimidophenoxy) -2,6-bis (1,1-dimethylethyl) benzene, 4,4'-(2-
Ethylhexylidene) -bis [1- (maleimidophenoxy)-
Benzene], 4,4 '-(1-methylheptylidene) -bis [1- (maleimidophenoxy) -benzene], 4,4'-cyclohexylidene-bis [1- (maleimidophenoxy) -3-methyl Benzene].

The low dielectric constant thermosetting resin composition of the present invention comprises:
A composition wherein the weight ratio of component (a) to component (b) is in the range of 1/99 to 99/1. If the component (a) is less than 1% by weight in the composition with the component (b), the toughness and adhesiveness of the resin are undesirably reduced. If the component (b) is less than 1% by weight in the composition with the component (a), the coefficient of linear expansion increases, and the heat resistance decreases. When the weight ratio is within the above range, a thermosetting resin composition having excellent heat resistance, toughness, adhesiveness and dielectric properties can be obtained.

In the resin composition of the present invention, it is of course possible to add a thermosetting resin or a thermoplastic resin other than the components (a) and (b) as long as the original properties are not impaired. If necessary, a release agent, a coloring agent, a flame retardant, a flame retardant auxiliary, a coupling agent and the like can be added.

Although the 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 must have 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 and mesitylene, methyl cellosolve, ethyl cellosolve, butyl cellosolve, isobutyl cellosolve, diethylene glycol. Monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monopropyl ether,
Various glycol ether solvents such as dipropylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, ester solvents such as methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, and ethyl acetate; ethylene glycol Dialkyl glycol ether solvents such as dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, N, N-dimethylacetamide, N, N-dimethylformamide, amide solvents such as N-methyl-2-pyrrolidone,
There are alcohol solvents such as methanol and ethanol,
These can be used in combination of several types.

The varnish obtained by dissolving the resin composition of the present invention in the above-mentioned solvent may be a woven glass cloth, a nonwoven glass cloth or paper,
Alternatively, a prepreg for a printed wiring board can be obtained by applying and impregnating a substrate such as a cloth containing a component other than glass and drying it in a drying oven at a temperature in the range of 80 to 200 ° C. The prepreg is used for producing a printed wiring board by heating and pressing, and the resin composition of the present invention has a low dielectric constant, a low dielectric loss tangent, excellent workability, excellent adhesiveness to metal, high heat resistance, and It is a thermosetting resin with excellent chemical resistance,
It is suitably used for laminates, metal-clad laminates and the like.

[0016]

The present invention will be described below in more detail with reference to examples.

(Synthesis Example 1 of Cyanate Ester Prepolymer) Four-necked 3 l equipped with a stirrer, thermometer and reflux condenser
In a separable flask, 4,4 '-(2-methylpropylidene)
After charging 1500 g of bis [3-methyl-6- (1,1,1-dimethylethyl) cyanatobenzene, 3.75 g of cobalt naphthenate in 10% nonylphenol solution was added, and the temperature in the system was adjusted using an oil bath. Was heated to 140 ° C. System 140
C., and stirring was continued. After 60 minutes, the oil bath was removed, and the contents were taken out of the system and cooled. Prepolymer obtained
As a result of measuring an IR spectrum of (I), from the appearance of characteristic absorption due to the triazine ring generation reduction and 1560 cm ^-1 of the characteristic absorption of cyanate groups of 2270 cm ^-1, trimerization of 30% of the cyanate group is in progress It was recognized that.

(Synthesis Example 2 of Cyanate Ester Prepolymer) In place of the cyanate ester compound used in Synthesis Example 1, 1500 g of 4,4'-bis (3,5-dimethyl-4-cyanatophenyl) methane was used. Thereafter, prepolymerization was performed in the same manner as in Synthesis Example 1. The trimerization ratio of the obtained prepolymer (II) was 40%.

Example 1 500 g of the cyanate ester prepolymer (I) obtained in Synthesis Example 1 above, 4,4 '-(2-methylpropylidene) bis [1- (4-maleimidophenoxy) -3- [Methyl-6- (1,1-dimethylethyl) benzene] was dissolved in 500 g of a mixed solvent of toluene / methyl ethyl ketone 1/1 to prepare a varnish solution so as to have a nonvolatile content of 50%. To this solution, a 10% nonylphenol solution of cobalt naphthenate was gradually added to give a gel time of 4 minutes ± 15 minutes.
Adjusted to seconds.

Thereafter, 57 parts by weight of a glass cloth (0.18 mm in thickness, E-glass manufactured by Nitto Boseki Co., Ltd.) were impregnated with 43 parts by weight of a varnish with a solid content using the varnish, and dried in a drying oven at 150 ° C. After drying for 4 minutes, a prepreg was prepared. The obtained prepreg was tack-free and excellent in workability. Eight pieces of the dried prepregs were stacked, and an electrolytic copper foil having a thickness of 35 μm was stacked on the upper and lower sides, and heated and pressed at a pressure of 40 kgf / cm ² and a temperature of 175 ° C. for 90 minutes to obtain a 1.6 mm-thick laminate. . After the surface copper foil of the laminate was removed by etching, the laminate was treated at 121 ° C. under a pressure cooker under a pressure of 2.0 atm for 20 hours, and the weight increase was measured. The same test piece was immersed in methylene chloride for 10 minutes at room temperature, and the appearance was checked to determine the solvent resistance. Table 2 shows the results.

The measurement of the dielectric constant and the dielectric loss tangent are based on JIS C 6481.
The capacitance was measured at a frequency of 1 MHz. JIS C 648 for solder heat resistance and peel strength
The solder heat resistance was measured at 260 ° C. for 300 seconds to check for any abnormal appearance. 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. Further, the coefficient of linear expansion in the thickness direction of the obtained laminate was measured by thermomechanical analysis. Table 2 shows the results together.

(Examples 2 to 4 and Comparative Examples 1 to 4) Laminates were manufactured in the same manner as in Example 1 except that the formulation was as shown in Table 1 and the results are shown in Table 2. .

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

As is clear from the results shown in Tables 1 and 2, the resin composition of the present invention has a low dielectric constant and a low dielectric loss tangent, and has excellent adhesiveness to metal, heat resistance and chemical resistance. It is a thermosetting 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.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-306165 (JP, A) JP-A-6-306166 (JP, A) JP-A-6-306168 (JP, A) 93735 (JP, A) JP-A-54-129100 (JP, A) JP-A-50-129700 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 73/00-73 / 26 C08L 79/00-79/08 CAPLUS (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] The present invention comprises a cyanate ester compound represented by the general formula (1) and / or a prepolymer (a) thereof, a bismaleimide compound represented by the general formula (2) and / or a prepolymer (b) thereof, A low dielectric constant thermosetting resin composition, wherein the weight ratio of (a) and (b) is in the range of 1/99 to 99/1. Embedded image (R _{1 to} R ₂₀ represent hydrogen or an alkyl group, and the total number of carbon atoms of R _{1 to} R ₁₀ and the total number of carbon atoms of R _{11 to} R ₂₀ are each 8
that's all)