JPH01123848A - Resin composition for laminating material and metal foil-clad laminate - Google Patents

Abstract

PURPOSE:To obtain the subject composition having a low dielectric constant and a low dielectric loss tangent and excelling in moldability, hot dimensional stability, copper foil peeling strength, adhesiveness, etc., by mixing a fluorocarbon resin organosol with a thermosetting resin and a fluorinated epoxy resin. CONSTITUTION:A fluorocarbon resin organosol (a) which is a sol consisting of 100pts.wt. fine fluorocarbon resin particles (e.g., tetrafluoroethylene/ hexafluoropropylene copolymer) homogeneously dispersed in an organic dispersing medium is mixed with 10-1,000pts.wt. thermosetting resin (c) (e.g., bismaleimide/triazine resin) and a fluorinated epoxy resin (c) (e.g., bisphenol AF epoxy resin) to obtain the title composition. A plurality of prepregs, as a laminating material, obtained by impregnating bases with the composition and drying them are laminated and a metal foil is laminated on at least either surface of the assemblage, followed by hot lamination pressing or bonding under applied heat and pressure.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a resin composition for a laminate useful for producing a laminate as a material for printed wiring boards, and a laminate and metal foil obtained from the resin composition. This invention relates to a metal foil-clad laminate formed by laminating layers.

[Prior Art] Conventionally, epoxy resin metal-clad laminates, bismaleimide-triazine resin metal-clad laminates, polyimide resin laminates, and the like have been widely used in printed wiring boards used in the electrical and electronic fields. Such a laminate is, for example, 250
It can be molded at low temperatures below ℃ and has good moldability. However, it has a drawback that it has a high dielectric constant and is not suitable for high frequency applications. -On the other hand, tetrafluoroethylene resin copper-clad laminates are commercially available as laminates with low relative permittivity, but the molding temperature is high at 300°C or higher (formability is poor, and thermal expansion in the thickness direction of the substrate is high). The coefficient is 1xl
It is thicker than O-'/'C (it has the disadvantage of poor thermal dimensional stability).

Under these circumstances, various improved metal foil-clad laminates have been proposed to eliminate the above-mentioned drawbacks, such as laminates made of a mixed system of tetrafluoroethylene resin powder and thermosetting resin such as epoxy resin. However, tetrafluoroethylene resin inherently has poor dispersibility, and even if a base material is impregnated with a mixed system with a thermosetting resin and a laminated material is formed, the laminated material is not uniformly impregnated. Obtaining wood was difficult. Therefore, even a laminate made by laminating such laminate materials has not been able to exhibit sufficient characteristics as a printed circuit board.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned problems faced by the prior art, and its purpose is to improve thermal stability through moldability and low expansion coefficient. A resin composition for laminates that provides a metal foil-clad laminate with excellent dimensional stability, good electrical properties, and excellent adhesion between layers and with metal foil, and a resin composition obtained using this composition. An object of the present invention is to provide a novel metal foil-clad laminate formed by laminating and molding a laminate material and a metal foil.

[Means for Solving the Problems] That is, the present invention provides a resin composition containing fa) a fluororesin organosol, (bl thermosetting resin, and (c) a fluorine-containing epoxy resin) as a resin composition for a laminated material. The present invention also provides a metal foil-clad laminate in which a laminate obtained by impregnating a base material with the resin composition and drying the resin composition and a metal foil are laminated.

In the present invention, (a
A fluororesin organosol is a sol in which fluororesin fine particles are uniformly dispersed in an organic dispersion medium. Examples of fluororesins that can be used include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTF[E), tetrafluoroethylene-hexafluorobrobylene copolymer (FEP), and polyvinylidene. Fluorolite (r'VdF), polyvinyl fluoride (PVF), tetrafluoroethylene-ethylene copolymer, chlorotrifluoroethylene-ethylene copolymer, tetrafluoroethylene-perfluorovinylether copolymer (PFΔ), etc. be able to. Therefore, polytetrafluoroethylene (PTFE) and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) are used because they are easy to prepare as an organosol and the prepared organosol has good stability. is preferred. Note that the above fluororesin is not limited to one type, and several types can be used in combination.

Regarding the method for preparing a fluororesin organosol using the fluororesin described in L, for example, British Patent No. 106484
No. 0, No. 1094349, U.S. Patent No. 2937+
Specifications of No. 56 and No. 3661831, Special Publication No. 1977
-310967ta, No. 48-17548, No. 49-1
The known methods described in each publication of No. 7016 are employed. Among the methods known above, preferred are those described in British Patent No. 1064840 and Japanese Patent Publication No. 47
- A method of obtaining an anhydrous organosol by dropping an aqueous dispersion of a fluororesin while heating an organic solvent that is azeotropic with water to remove water as an azeotrope of the organic solvent, as described in Japanese Patent No. 31096; Or special public service Sho 49-17016
A layer transfer agent, which is an organic solvent that is insoluble or poorly soluble in water and does not physically or chemically damage the fluororesin, is added to the aqueous dispersion of the fluororesin described in the publication, and stirred to form the fluororesin. This is a method in which the aqueous layer is inverted from the aqueous layer to the inversion medium, and the aqueous layer is removed.

The organic solvent used as a dispersion medium for the fluororesin organosol is not particularly limited as long as it does not physically or chemically alter the aqueous dispersion of the fluororesin, but from the point of view that the resulting organosol has good stability. and preferably methyl ethyl ketone, methyl isobutyl ketone,
These include ketones such as acetone, and aromatic hydrocarbons such as benzene, toluene, and xylene.

Used with fluororesin organosol (b)
Examples of the thermosetting resin include bismaleimide/triazine resin, polyaminobismaleimide resin (addition type imide resin), epoxy resin, unsaturated polyester resin, phenol resin, urethane resin, and acrylic resin. From the viewpoint of good heat resistance and electrical properties, preferred are bismaleimide triazine resin, polyamino bismaleimide resin, epoxy resin, and the like.

Furthermore, bisphenol AF type epoxy resin is preferably used as the (c) fluorine-containing epoxy resin contained in the resin composition, and (meth)acrylic acid ester having a polyfluoroalkyl group is preferably used in the epoxy resin. It is also possible to use a composition in which an epoxy resin contains a polyfluoroalkyl group-containing composite obtained by polymerization (see Japanese Patent Application No. 120060/1986).

In the resin composition, the blending ratio of (bl thermosetting resin to (a) fluororesin organosol is 10 parts by weight per 100 parts by weight of fluororesin as the solid content of the organosol.
-1000 parts by weight, preferably 20-500 parts by weight. If the amount is less than 10 parts by weight, the mechanical strength of the laminated material obtained by impregnating the base material and curing will be low; on the other hand, if it exceeds 10,001 parts by weight, the electrical properties of the laminated material No improvement effect can be obtained.

(c) The amount of fluorine-containing epoxy resin may be the same as or higher than that of the thermosetting resin, but if it is in a large amount as in the case of the thermosetting resin, the heat resistance of the laminated material may be affected. It is determined by considering the relationship with the total amount of resin since it has an unfavorable effect on the amount of resin. Therefore, it is preferably about half the amount or less of the thermosetting resin.

The resin composition of the present invention containing (a) fluororesin organosol, (bl thermosetting resin, and (c) fluorine-containing epoxy resin) is impregnated into a base material for a laminate to form a laminate. Examples of such substrates include inorganic fibers such as glass, asbestos, and silica fibers, organic synthetic fibers such as polyester, polyamide, polyvinyl alcohol, and acrylic, woven fabrics, nonwoven fabrics, or mats made of natural fibers such as cotton, and paper. Any material that is generally used as a base material for laminated materials can be used without particular limitation, such as a combination of the following.Particularly preferred are glass fiber woven fabric, nonwoven fabric, or paper.

A method for impregnating a base material for a laminate such as a pair of legs with a resin composition can be carried out by a known method. The substrate impregnated with the composition is dried to remove the solvent and to form a so-called prepreg as a laminate. Room temperature is sufficient for this drying condition, but heating can be used if necessary.

The thus obtained prepreg as a laminate is made into a laminate by laminating a plurality of sheets, further laminating metal foil on one or both sides, and then forming a metal foil-clad laminate by hot lamination pressing or hot pressure bonding. It is said that The hot lamination press or the hot pressure bonding can be performed using a commonly used device such as a hot press. Furthermore, lamination with metal foil is not limited to hot lamination press or hot pressure bonding. For example, the above laminated materials are laminated to form a pre-cured plate-like body, and the plate-like body and metal foil are bonded together using an adhesive. It is also possible to laminate the layers through the layers.

Materials for the metal foil in the present invention include commonly used copper foil, aluminum foil, iron-based alloy foil, and the like.

[Function] The fluorine-containing resin contained in the resin composition of the present invention has the effect of improving electrical properties such as dielectric properties in the laminate, and the thermosetting resin has the effect of imparting good moldability. It is considered to have. Furthermore, fluorine-containing epoxy resin not only improves electrical properties but also improves the adhesion of the composition obtained by impregnating and drying the resin composition into the base material for laminated materials, and also improves the adhesion between the laminated materials and metal foil. It is presumed that it has an effect that contributes to improving adhesiveness.

[Example] Example 1 In a reactor equipped with a stirrer, 100 parts of an aqueous dispersion containing 50% of a tetrafluoroethylene-hexafluoropropylene co-in combination (FEP) (parts by width, the same applies hereinafter) and n- 100 parts of hexane were added and mixed with stirring. Subsequently, 300 parts of acetone was gradually added while stirring was continued. After adding acetone, it was confirmed that the soft paste-like FEP polymer was transferred from the aqueous layer to the raw hexane.

Next, the aqueous layer was removed by decantation, 300 parts of acetone was added, and decantation was repeated three times, followed by filtration to obtain a grease-like, highly concentrated FEP polymer organosol. Bismaleimide triazine resin (
“B T 2170”: Manufactured by Mitsubishi Gas Chemical Co., Ltd.) 12.
6 parts of bisphenol AF type epoxy resin and 6 parts of bisphenol AF type epoxy resin, and further added methyl ethyl ketone to adjust the solid content concentration (F
EP50: Bismaleimide triazine resin 12.5)
A varnish was obtained as a composition.

A glass cloth having a bulk specific gravity of 48 g/d was impregnated with the above varnish and pulled up, and then dried at room temperature to obtain a prepreg as a laminate having a resin content of 88%. These four sheets of prepreg are laminated, and one layer of surface-treated copper foil with a thickness of 0.018 mm is placed on each side of the prepreg, and then this is sandwiched between molds. molding pressure 2
0g/cm” at 180°C for 1 hour, then at 220°C.
It was held at ℃ for 4 hours and molded to obtain a double-sided copper-clad laminate.

The physical properties of this double-sided copper-clad laminate were measured in accordance with JISC6481. The results are shown in Table 1.

Example 2 22 parts of bismaleimide triazine resin added to the organosol in Example 1, and further bisphenol AF
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that the mold epoxy resin was changed to 11 parts.

The properties of this laminate were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 3 In place of the bismaleimide triazine resin added to the organosol in Example 1, 6.5 parts of bisphenol A type epoxy resin with an epoxy equivalent of 471 were added, and to this were added 6 parts of bisphenol AF type epoxy resin, 0.5 parts of dicyandiamide, A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that 0.025 part of benzyldimethylamine was used.

The properties of this laminate were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 4 70 parts of the aqueous dispersion of FEP in Example 1 and 70 parts of polytetrafluoroethylene (P T
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 except that 25 parts of the aqueous dispersion of F E ) was used.

The properties of this laminate were measured in the same manner as in Example 1. The results are shown in Table 1.

Example 5 First, a fluorine-containing epoxy resin was prepared as follows. Bisphenol A epoxy resin (“Epicote 8”)
28″ (manufactured by Dioilka Ciel Epoxy Co.) 75 parts, CI+□=
29 parts of C(cI+, 1COOC2t1.C,F) and 0.1 part of azobisisobutyronitrile were mixed and reacted at 60° C. for 20 hours with stirring to obtain an epoxy resin composition.

Next, a double-sided copper-clad laminate was prepared in the same manner as in Example 1, except that the above epoxy resin composition was used in place of the bisphenol AF type epoxy resin used in the preparation of the varnish as the composition in Example 1. Obtained.

The properties of this laminate were measured in the same manner as in Example 1. The results are shown in Table 1.

Ratio 1 Bite Example 1 Using a varnish prepared from 60 parts of bismaleimide triazine resin and 40 parts of methyl ethyl ketone, Example 1
A double-sided copper-clad laminate was obtained in the same manner as above. The properties of this laminate were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 25 parts of bisphenol A epoxy resin with an epoxy equivalent weight of 471, 1 part of dicyandiamide, 0.05 part of pencil dimethylamine, 15 parts of acetone, 10 parts of methyl cellosolve
A double-sided copper-clad laminate was obtained in the same manner as in Example 1 using the varnish prepared from the above. Example 1 The characteristics of this laminate
The results are shown in Table 1.

Ratio 1 Bite Example 3 Example 1 except that bisphenol ΔF type epoxy resin was not added in the preparation of the varnish as the composition of Example 1.
A double-sided copper-clad laminate was obtained in the same manner as above. The properties of this laminate were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4)) 50 parts of "I" FE powder, bismaleimide.
A varnish was prepared by mixing 12.5 parts of triazine resin and 94 parts of methyl ethyl ketone, but the PTFE powder agglomerated, making it impossible to prepare a brief leg by impregnating glass cloth.

Table 1 [Effects of the Invention] The resin composition for laminated materials of the present invention and the metal foil-clad laminates made of laminated materials using the composition have characteristics as clear from the comparison between Examples and Comparative Examples. It has an excellent effect of having low dielectric constant and dielectric loss tangent. In addition, the copper foil has high peel strength, excellent adhesive properties, and good water and humidity resistance. Furthermore, since there is a wide range of thermosetting resins to choose from, it also has the effect of improving, for example, thermal dimensional stability by using a suitable resin with moldability and low expansion coefficient.

Claims (2)

[Claims] 1. A resin composition for a laminated material, comprising (a) a fluorine-based resin organosol, (b) a thermosetting resin, and (c) a fluorine-containing epoxy resin. 2. A laminated material and metal foil obtained by impregnating a base material with a resin composition for a laminated board containing (a) a fluororesin organosol, (b) a thermosetting resin, and (c) a fluorine-containing epoxy resin and drying the resin composition. A metal foil-clad laminate made of laminated sheets.