JPH0388810A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide the subject composition containing a specific bismaleimide compound as an essential component, giving a three-dimensionally crosslinked cured product by the polymerization reaction of double bond, having excellent moldability, high heat-resistance, low dielectric constant and excellent electrical properties and suitable as an insulation material. CONSTITUTION:The objective composition contains a bismaleimide compound of formula as essential component and further contains preferably a cyanamide compound, cyanato compound, isocyanato compound, epoxy compound, other maleimide compound or various kinds of vinyl compounds.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a thermosetting resin composition, and in particular, it is suitable as an insulating material having excellent moldability, heat resistance, low dielectric constant, and electrical properties. The present invention relates to a resin composition.

[Conventional technology]

Conventionally, fluororesins such as polytetrafluoroethylene (PTFE) and hydrocarbon resins such as polyethylene and polybutadiene have been known as low vI electric constant insulating materials.
It has been widely applied.

These have a dielectric constant of 3 or less. However, fluororesins are superior in terms of heat resistance and electrical properties.

Since these are thermoplastic resins, they generally have a softening temperature. At temperatures higher than the softening temperature, a rapid decrease in mechanical strength and an increase in the coefficient of thermal expansion are observed, resulting in a significant decrease in material properties.

Therefore, it cannot be used in the region above the softening temperature, and is a material whose field of application is limited. Furthermore, since there is no suitable solvent for making varnish with PTFE, it is generally heated and melt-molded. The molding temperature is as high as 300° C. or higher, and the melt viscosity is very high, so it is a material with poor moldability and workability. On the other hand, many hydrocarbon-based thermosetting resins such as butadiene resin and allyl resin have been developed. These have a three-dimensional crosslinked structure and can be expected to be applied in the field of highly heat-resistant materials that require mechanical strength and two-dimensional stability at high temperatures.

However, hydrocarbon resins are easily oxidized and have poor thermal decomposition properties, as can be inferred from their chemical structures.

Therefore, it is hardly used as a highly heat-resistant material. In fields where such heat resistance is required, many resins having heteroaromatic rings such as imide rings are used. Typical examples include polyimide, polybenzimidazole, and polybenzothiazole. Among these, bismaleimide compounds in particular are used as additive heat-resistant materials that do not generate side reaction products such as condensed water during curing reactions, and are used in many fields such as various structural materials, FRP, molding materials, wiring boards, and LSI interlayer insulating films. ing.

[Problem to be solved by the invention]

However, bismaleimide compounds have a problem in that they have a higher dielectric constant than low dielectric constant materials. Many bismaleimide compounds that have been developed so far have dielectric constants of 3 or more. Bis(4-maleimidophenyl)methane (hereinafter referred to as BMI), which is a typical example of this compound, has a melting temperature (1
58℃) and polymerization temperature (180℃) are almost the same, and the processing window (hereinafter referred to as P
W) is extremely small and is 20°C. Within this PW range, the material exhibits fluidity and is moldable. Therefore, BMI is generally rarely used as a single composition. A prepolymerization reaction with diamines, reactive elastomers, etc. is used to increase the molecular weight and lower the melting temperature. Only through such improvements can it be used as a molding material. However, addition of the second component generally results in a higher dielectric constant than that of the second component alone, and is not suitable for the field targeted by the present invention.

An object of the present invention is to provide a bismaleimide compound having a low dielectric constant, a high polymerization temperature, and a large PW. The resin composition of the present invention is a low dielectric constant insulating material with excellent moldability and heat resistance.

[Means to solve the problem]

The above object can be achieved by a thermosetting resin composition characterized in that it uses the bismaleimide compound represented by as an essential component and obtains a three-dimensionally crosslinked cured product through a double bond polymerization reaction. At this time, a resin composition with excellent moldability can be obtained by combining various compounds copolymerizable with the double bond of maleimide within a range that does not impair the desired heat resistance and electrical properties.

Such compounds include cyanamide compounds.

Cyanato compounds, isocyanate compounds, epoxy compounds, maleimide compounds, vinyl compounds, etc. are useful. Other similar products include various primary to quaternary amine compounds,
Carboxylic acid compounds, polyamides, phenolic resins, melamine resins, urea resins.

There are also urethane resins, polyamino bismaleimide resins, etc. These are used in polymer, oligomeric, and monomeric units. Such resin compositions have functional groups such as polymerizable double bonds or triple bonds in their molecular structures, and undergo crosslinking reactions under heating, light irradiation, or the presence of radical polymerization initiators. The resulting cured product has a three-dimensional network structure.

This becomes a heat-resistant insulating material that maintains mechanical properties, two-dimensional stability, etc. even at high temperatures. Furthermore, since reaction by-products such as condensed water are not generated in this crosslinking and curing reaction, there is an advantage that it can be applied in many fields such as various structural materials and molding. This is different from typical heat-resistant insulating materials such as polyimide, polybenzimidazole, and polybenzothiazole.

A typical bismaleimide compound is bis(4-maleimidophenyl)methane (BMI). However, B
MI has a high dielectric constant of 3.3 and a melting temperature (1
58°C) and the polymerization temperature (180°C) are almost the same, and the temperature difference between them, PW, is only 20°C. In addition, BMI alone has the disadvantage that the obtained cured product has a high elastic modulus and is very brittle. Therefore, BMI is generally rarely used as a single composition; it is usually used as a molding material by prepolymerizing with diamine, dithiol, reactive elastomer (liquid rubber), etc. In general, these materials often have a higher relative dielectric constant than those used alone.

Therefore, bismaleimide compounds have been developed in which flexibility is imparted by introducing an ether group with a large curvature into the structure.A typical example is 2.2-(bis(4
-maleimidophenoxy)phenyl)propane.

This compound can be used alone as a molding material, and the resulting cured product has a lower elastic modulus and an improved breaking strength. However, the dielectric constant is relatively high at 3.1.

The present invention aims to solve these two problems by introducing a fluorine group into the bismaleimide structure having this ether skeleton. By increasing the molar specific volume of the cured product obtained by using fluorine groups, the dielectric constant could be reduced, and a bismaleimide compound having a dielectric constant of 3 or less could be obtained. In addition, by introducing an electron-withdrawing fluorine group near the maleimide ring where the double bond of the functional group is located,
The electron density on the carbon of the double bond can be reduced and the reactivity can be significantly reduced. This made it possible to move the polymerization temperature to a higher temperature side, increase PW, and raise it to 100° C. or higher.

Since the PW is large and the resulting cured product is highly flexible, it does not require a second component such as diamine, so it can be used as an insulating material without increasing the dielectric constant.

For fluorine groups, molar specific volume.

A high fluorine content is desirable from the viewpoint of maximizing the electron-withdrawing effect. From this point of view, trifluoromethyl group is the best.

In the present invention, trifluoromethyl groups are introduced into each benzene ring close to the maleimide ring to reduce the reactivity of the double bond. There is a concern that if two or more are introduced, the reactivity will be further reduced and the practicality as a molding material will be lost. Therefore,
From the perspective of lowering the dielectric constant, we fluorinated the propane skeleton at the center of the molecular structure, which is thought to have little effect on the reactivity of double bonds. As described above, the cured product using the bismaleimide compound represented by formula (1) has good moldability.

It was discovered that it has excellent heat resistance, electrical properties, etc.

The cured product is obtained by filling a mold or the like in the temperature range of PW in a molten state, and then raising the temperature to a predetermined polymerization temperature or higher to proceed with a crosslinking reaction. At this time, if a radical polymerization initiator such as peroxide is added, the polymerization temperature can be moved to a lower temperature side, and the reaction time can also be reduced. Examples of such radical polymerization initiators include benzoyl peroxide and parachlorobenzoyl peroxide.

2.4-dichlorobenzoyl peroxide, lauroyl peroxide, dicumyl peroxide, acetyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, bis(1-hydroxycyclohexyl peroxide), 2.5-dimethylhexane-2,
5-dihydroperoxide, t-butylperbenzoate, 2゜5-dimethyl-2,5-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-(t-butylperoxy)hexane- 3,2,5-dimethylhexyl-2,5-di(peroxybenzoate), cumene hydroperoxide, t-butyl hydroperoxide, t
-Butyl peroxybenzoate, t-butyl peroxy acetate, 1-butyl peroxy octate, t-
Examples include butyl peroxyisobutyrate, dibenzyl peroxide, di-t-butyl peroxy phthalate, and the like.

These may be used alone or in combination.

The amount of the polymerization initiator to be blended is 0.01 to 5 parts by weight per 100 parts by weight of the resin composition, particularly preferably 0.01 to 5 parts by weight.
It is 1 to 3 parts by weight. In addition, if necessary, a polymerization accelerator,
A retardant, various pigments, fillers, etc. may be added.

〔Example〕

<Example 1> 1.1. l, 3,3.3-hexafluoro-2゜2-bis[(4-maleimido-2-trifluoromethylphenoxy)phenyl]propane (p-HFBP) (Central Glass) 100 g and 2,2-bis[( 4-cyanoaminophenoxy)phenyl]propane (Manatsuk) 100
g was dissolved in 300 g of acetone, and 0.5 g of t-butyl hydroperoxide (NOF) was added as a radical polymerization initiator.
After adding g, the solvent was removed by vacuum drying to obtain a powder sample. The obtained sample was press-molded using a 2 m thick spacer to obtain a cured resin plate. Curing conditions are 1
After melting the sample at 50° C., the temperature was raised to 250° C. and heated and pressurized for 1 hour. The dielectric constant, thermal expansion coefficient, and thermal decomposition temperature of the obtained resin plate were measured. Also, the melting point of the resin composition.

Polymerization temperature was measured by differential thermal analysis.

<Example 2> 100 g and 1 of p-HFBP used in Example 1.

1.1,3,3,3-hexafluoro-2,2-bis(
4-cyanatophenyl)propane (Manatsuk) 100g
After dissolving in 300 g of acetone, a powdery composition was obtained by vacuum drying. A cured product was obtained by press molding only by thermal polymerization without the addition of a radical polymerization initiator. The curing conditions were such that the sample was first melted at 150°C, then heated to 250°C for 1 hour, and then heated and pressurized at 280°C for 1 hour. The properties of the obtained resin composition and resin plate were evaluated in the same manner as in Example 1.

<Example 3> 1.1,1,3,3.3-hexafluoro-2゜2-bis[(5-maleimido-3-trifluoromethylphenoxy)phenyl]propane (m-HFBP) (Central Glass) 100 g of 2,2-bis[(4-maleimidophenoxy)phenyl]propane (BBMI) (Hitachi Chemical) were dissolved in 300 g of acetone, and 2,5-dimethyl-2,5-(t- After adding butylperoxy)hexyne-3 (NOF) Ig, the solvent was removed by vacuum drying to obtain a powder sample. The obtained sample was molded using a mold using a 2 m thick spacer to obtain a resin plate. The curing conditions were such that the sample was first melted at 150°C, defoamed, and heated to 250°C for 1 hour. The properties of the obtained resin composition and resin plate were evaluated in the same manner as in Example 1.

<Example 4> p -HF B P l 00 g used in Example 1 and 2゜2-bis(4-allyloxyphenyl)propane 1
00g in 200g of methyl isobutyl ketone, 1
Prepolymerization was performed under reflux at 20'C for 160 minutes. After cooling to room temperature, 0.2 g of dicumyl peroxide (NOF) was added as a radical polymerization initiator, and the solvent was removed by vacuum drying to obtain a powder sample. The obtained sample was press-molded in the same manner as in Example 1 to obtain a resin plate. The curing conditions were heating and pressure at 200° C. for 1 hour. The properties of the obtained resin composition and resin plate were evaluated in the same manner as in Example 1.

[Comparative example]

Comparative Example 1> A resin plate was obtained using only p-HFBP used in Example 1 under the same conditions as in Example 1, and its properties were evaluated.

<Comparative Example 2> BBMI (Hitachi Chemical) used in Example 3 was obtained by press molding in the same manner as in Example 1. The curing conditions were as follows: After melting the sample at 180°C, the temperature was raised to 220°C, followed by heating and pressurizing for a certain period of time. The properties of the obtained resin plate were evaluated in the same manner as in Example 1.

The results of Examples and Comparative Examples are shown in Tables 1 and 2.

Table 1 Characteristics of cured product Table 2 Melting point and polymerization initiation temperature 〔Effect of the invention〕

Claims (1)

[Claims] 1. Obtaining a three-dimensionally cross-linked cured product by a polymerization reaction of double bonds using a bismaleimide compound represented by (1) as an essential component. A thermosetting resin composition characterized by: 2. A thermosetting resin composition using the bismaleimide compound and cyanamide compound according to claim 1. 3. A thermosetting resin composition using the bismaleimide compound and cyanato compound according to claim 1. 4. A thermosetting resin composition using the bismaleimide compound and isocyanate compound according to claim 1. 5. A thermosetting resin composition using the bismaleimide compound and epoxy compound according to claim 1. 6. A thermosetting resin composition using the bismaleimide compound according to claim 1 and another maleimide compound. 7. A thermosetting resin composition using the bismaleimide compound according to claim 1 and various vinyl compounds or polymers thereof. 8. The thermosetting resin composition according to claim 1, wherein the polymerization reaction of the double bond is thermal polymerization. 9. The thermosetting resin composition according to claim 1, wherein the polymerization reaction of the double bond is polymerization in the presence of a radical polymerization initiator such as a peroxide. 10. The thermosetting resin composition according to claim 1, wherein the polymerization reaction of the double bond is photopolymerization such as UV irradiation. 11. The thermosetting resin composition according to claim 1, having a dielectric constant of 3 or less.