JPH0258390A - Resin substrate for high frequency - Google Patents

Abstract

PURPOSE:To enlarge interlayer bonding force and metallic foil adhesive strength by keeping resincomposition, which contains polyphenylene oxide, crosslinkable polymer and/or monomer, and crosslinkable prepolymer, at a specific temperature so as to make it into a compact, or impregnate a base material with it. CONSTITUTION:Resin composition which contains polyphenylene oxide, crsslinkable polymer and/or monomer, and crosslinkable prepolymer is kept above 40 deg.C so as to make it into a compact or impregnate a base material with it. The polyphenylene oxide is high in glass transition point and is thermosetting resin with low permittivity and with low dielectric loss factor. To improve its heat resistance, chemical resistance, processability, and dimension stability without losing the high frequency performance of resin of a resin substrate, it is made to contain crosslinkable polymer and/or monomer excellent in high frequency performance. To make the contraction during hardening of the resin composition small to lower the internal stress and to improve the interlayer bonding force of a laminate and the metallic foil adhesive strength, the resin composition is made to contain crosslinkable prepolymer. To improve the interlayer bonding force of the laminate and the metallic foil adhesive strength, it is used at the vanish temperature of the resin composition above 40 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a high frequency resin substrate. More specifically, the present invention relates to a resin substrate useful for high frequency laminates that has excellent high frequency characteristics, interlayer adhesion strength, and metal foil adhesive strength.

(Prior art) Laminated boards for wiring of electrical and electronic devices such as precision instruments, electronic computers, and communication equipment are required to have high interlayer adhesion and metal foil adhesion as basic properties. High-frequency performance (
Dielectric constant ε and dielectric loss tangent tan δ) are also required.

Conventionally, resin substrates for laminates with strong interlayer adhesion and metal foil adhesion have been known to use epoxy resins and imide resins, and poly-4-fluoride has excellent high frequency performance. One using ethylene chloride resin is known.

(Problems to be Solved by the Invention) However, resin substrates using epoxy resins and imide resins have excellent interlayer adhesion and metal foil adhesion and can ensure sufficient moldability, but have a problem in that they are inferior in high frequency performance. It has points. On the other hand, those using poly-4-fluoroethylene resin have excellent high frequency performance, but have the drawback of being extremely expensive.

This invention was made in view of the above circumstances, and it solves the problems of conventional resin substrates, has high interlayer adhesion and metal foil adhesion, has good high frequency performance, and is manufactured at low cost. The aim is to provide a new resin substrate that can

(Means for Solving the Problems) 'In order to solve the above problems, the present invention provides a resin composition containing polyphenylene oxide, a crosslinkable polymer and/or monomer, and a crosslinkable prepolymer at a temperature of 40°C or higher. We present a high frequency resin substrate which is formed by molding or impregnating it into a base material.

The polyphenylene oxide used in the high-frequency resin substrate of this invention is a thermosetting resin with a relatively high glass transition point, low dielectric constant, and low dielectric loss, and has attracted attention in recent years because it is inexpensive. . This polyphenylene oxide has, for example, the following general formula (1) (R represents hydrogen or a hydrocarbon group having 1 to 3 carbon atoms,
Each R may be the same or different, and examples thereof include poly(2,
6-dimethyl-1,4-phenylene oxide).

Although the molecular weight is not particularly limited, for example,
Weight average molecular weight (M w ) is 10,000 to ao, oo
o, molecular weight distribution Mw/M n =2.0 to 6.0 (M
Preferably, n is approximately the same as the number average molecular weight.

In this invention, in order to improve the heat resistance, chemical resistance, processability, and dimensional stability of the resin of the resin substrate without impairing the high frequency performance of the resin, high frequency Contains crosslinkable polymers and/or monomers with excellent performance.

Examples of crosslinkable polymers include 1,2-polybutadiene, 1,4-polybutadiene, styrene-butadiene copolymer, polystyrene, modified 1,2-polybutadiene (maleic modification, acrylic modification, epoxy modification), rubbers, etc. , each can be used alone or in combination of two or more. These polymers may be in the form of elastomers or rubbers; particularly preferred examples include styrene-butadiene copolymers and/or polystyrene.

However, when manufacturing the resin substrate of the present invention using a sheet by the casting method described below, it is preferable to use polystyrene having a relatively high molecular weight in order to improve the film forming properties of the sheet.

Examples of crosslinking monomers include acrylates such as ester acrylates, epoxy acrylates, and urethane acrylates; polyfunctional compounds such as triallyl cyanurate, triallyl isocyanurate, ethylene glycol dimethacrylate, divinylbenzene, and diallyl phthalate. Monomers, monofunctional monomers such as vinyltoluene and ethylvinylbenzene, and polyfunctional epoxies are listed, and each can be used alone or in combination of two or more.

Among these, triallyl cyanurate and/or triallyl isocyanurate are preferred because they have good compatibility with polyphenylene oxide and improve film-forming properties, crosslinking properties, heat resistance, and dielectric properties.

Triallyl cyanurate and triallyl isocyanurate are chemically structurally isomers and have similar film-forming properties, compatibility, solubility, reactivity, etc., so both are similar. It can be used for.

The above crosslinkable polymers and crosslinkable monomers are
Although either one of them may be used or both may be used together, using them together is more effective in improving the characteristics.

In this invention, the above polyphenylene oxide, crosslinkable polymer and/or In addition to monomers,
Furthermore, a crosslinkable prepolymer is included in the resin composition.

As the crosslinkable prepolymer, prepolymers of the above-mentioned crosslinkable monomers can be used, and triallyl cyanurate prepolymers and triallyl isocyanurate prepolymers can be particularly preferably used.

An initiator can be used when curing such a resin composition.

The type of initiator is appropriately selected depending on whether the resin composition is of an ultraviolet curing type or a thermosetting type.

In that case, a single type of initiator may be used, multiple types of initiators may be used, or an initiator for ultraviolet curing type and an initiator for thermosetting type may be used in combination. .

It goes without saying that the resin composition used for the resin substrate of the present invention may contain various additives as long as they do not impair its properties. For example, brominated polyphenylene oxide, brominated bisphenol, Type polycarbonate etc. can be contained. In addition, inorganic powder such as ceramic dielectric powder can be contained in order to control the dielectric constant and improve shapeability.Furthermore, in order to prevent embrittlement of the resin when inorganic powder is contained, glass A fibrous reinforcing material such as fiber or aramid fiber can be included.

The blending ratio of such a resin composition is a crosslinkable polymer used together with polyphenylene oxide, a crosslinkable monomer,
It can be determined depending on the type of crosslinkable prepolymer, the molding method applied to the resin composition, etc. For example, 10 to 70 parts by weight of polyphenylene oxide, up to 30 parts by weight of styrene-butadiene copolymer and/or polystyrene, 10 to 60 parts by weight of triallyl isocyanurate and/or triallyl cyanurate, triallyl isocyanurate prepolymer and/or Preferred examples include compositions containing 5 to 40 parts by weight of allyl cyanurate prepolymer.

Further, the blending ratio of the initiator to be included in addition to such a blend is 0.1 to 5 parts by weight (more preferably 0.1 to 5 parts by weight).
If the proportion of the initiator is less than the above range, the curing of the polyphenylene oxide resin composition may be insufficient, and if it exceeds the above range, it may adversely affect the physical properties after curing. There is ξ.

The above resin composition is usually dissolved in a solvent to form a dispersed mixture (varnish). Examples of the solvent include halogenated hydrocarbons such as trichloroethylene, trichloroethane, chloroform, methylene chloride, and chlorobenzene, benzene, toluene, Aromatic hydrocarbons such as xylene, acetone, carbon tetrachloride, etc. can be used, especially benzene,
Aromatic hydrocarbons such as toluene are preferred, and these can be used alone or in combination of two or more.

Such a resin composition can be formed into various desired shapes including sheets by molding or impregnating it into a base material, but in this invention, the molecular chains of the polymer component are sufficiently spread. In order to impart appropriate flexibility to the cured resin and improve the interlayer adhesive strength of the resin substrate and the adhesive strength of the metal foil, the temperature of the resin composition (varnish temperature)
The temperature is 40°C or higher, preferably 55°C or higher.

There are no particular restrictions on the method of forming the resin substrate as long as the resin composition is heated to 40°C or higher. In other words, a sheet substrate is formed from the resin composition, or a prepreg is formed by impregnating the resin composition into a base material. Further, if necessary, a core material or the like is manufactured from these sheet substrates or Gripregs, and then these are multilayered and integrated with other base materials, films, Gripregs, metal foils, etc. according to a conventional method.

In this case, the sheet substrate made from the resin composition is, for example,
It can be formed by a casting method. The casting method is a method in which a resin composition mixed with a solvent is formed into a thin layer by casting or coating, and then the resin composition is cured by removing the solvent. According to the casting method, a cured product can be obtained at a relatively low temperature without using the costly calendar method. To explain this casting method more specifically, the resin composition mixed with a solvent is placed on a mirror-treated iron plate or a carrier film for casting, etc.
The sheet 6 is obtained by casting or coating to a thickness of 00 (preferably 5 to 500) μI and thoroughly drying to remove the solvent.

The carrier film for casting is not particularly limited, but it is preferably one that is insoluble in the above solvents, such as polyethylene terephthalate film, polyethylene film, polypropylene film, polyester film, or polyimide film, and preferably one that has been subjected to mold release treatment.

Drying is carried out by air drying or hot air drying, etc. The upper limit of the temperature range in this case must be lower than the boiling point of the solvent or lower than the thermal temperature of the carrier film for casting (no The lower limit is determined by drying time, processability, etc. For example, when trichlorethylene is used as a solvent and PET film is used as a carrier film for casting, it is preferable to
It is preferable to set the temperature to 0° C., and if the temperature is increased within this range, the drying time can be shortened.

When producing one leg by impregnating a base material with a resin composition, the following method can generally be used.

That is, the resin composition is dispersed in a solvent, and the base material is immersed in the solvent dispersion (dipping) to impregnate and adhere the resin composition to the base material.

Then, the solvent is removed by drying or the like, or semi-cured to bring it to the B stage. The amount of impregnation of the resin composition in this case is not particularly limited, but is preferably 30 to 80% by weight. The base material is not particularly limited, and examples include glass cloth, aramid cloth, polyester cloth, etc. It is possible to use a loss-like material that can be impregnated with vIJ resin such as nylon cloth, a mat-like material made of these materials and/or a fibrous material such as non-woven fabric, paper such as kraft paper, linter paper, etc. Such prepregs do not require melting the resin, and therefore can be easily produced at relatively low temperatures.

As the metal foil for circuit formation used when forming the resin substrate, a wide variety of metal foils used for ordinary wiring boards can be used. For example, metal foil such as copper foil or aluminum foil can be used. In this case, it is preferable that the metal foil has a smooth adhesion surface and good conductivity in order to improve dielectric properties.

Such metal foil can be formed by vapor deposition, etc., but it can also be formed into a desired conductor (circuit, electrode, etc.) by subtractive method, additive method (full additive method, semi-additive method), etc. It's okay.

A method for manufacturing a laminate using a core material, sheet, and 7-repreg manufactured from a resin composition includes, for example, combining a predetermined number of appropriately dried sheets and/or prepregs to a predetermined design thickness; If necessary, metal foils are also combined and laminated, and the resin is melted by heating and pressing to bond sheets to each other, sheets to Gripreg or core material, prepregs to each other, sheets and metal foil, and prepreg and metal foil to each other. to form a laminate.

Strong adhesion is obtained by this fusion, but even stronger adhesion can be obtained if the heating at this time causes a crosslinking reaction by a radical initiator.

Note that such adhesion may be performed using an adhesive in combination.

Here, the combination of sheets, prepregs, and core materials when used together is not particularly limited, but it is preferable to use vertically symmetrical combinations to prevent warping after molding and secondary processing (etching, etc.). Further, it is preferable to combine the sheets so that they are placed on the adhesive interface with the metal foil, since the adhesive force can be improved.

The temperature during heat pressing depends on the combination of metal foil and sheet or prepreg, but for example, the heat fusion properties of the sheet can be used to bond metal foil and sheet, so the lamination pressing temperature depends on the glass of the sheet. Above the transition point, about 16
It is preferable to keep the temperature in the range of about 0 to 300°C, and
When thermally crosslinking a resin composition, the crosslinking reaction depends on the reaction temperature of the initiator used, so the heating temperature and heating time are determined depending on the type of initiator. For example, the temperature is 150 to 300°C and the time is about 10 to 60 minutes.

Pressing is performed to bond sheets to each other, sheets to prepreg, prepregs to prepreg, metal foil to sheet, metal foil to Gripreg, etc., and to adjust the thickness of the laminate, so press conditions are selected as necessary. For example, pressure 20-70kg/-
It can be done to a certain extent.

In the heat-pressing method described above, a predetermined number of sheets and/or prepregs are heated and laminated in advance, metal foil is superimposed on one or both sides of the sheets, and the sheets and/or prepregs are heat-pressed again. Good too.

(Function) The resin composition used in the present invention provides a resin substrate with excellent high frequency performance.

In addition, since this resin composition contains a crosslinkable prepolymer, shrinkage during curing is small and internal stress is reduced, so the resulting laminate has improved interlayer adhesion and metal foil adhesion strength. Become.

Furthermore, by heating this resin composition to 40°C or higher and using it to form a laminate, the polymer in the resin composition can be
Since the component molecules can be cured with sufficient spread, the interlayer adhesive strength and metal foil adhesive strength of the laminate can be further improved.

Next, examples will be shown to further explain the high frequency resin substrate of the present invention.

Examples 1 to 5 Polyphenylene oxide, styrene-butadiene copolymer (Solrun T406: Asahi Kasei Corporation ■), triallyl isocyanurate monomer (n-
TAIC + Nippon Kasei■) or triallyl cyanurate monomer (1-TAC),) reallylyl isocyanurate glebolimer (p-TAIC) or triallyl cyanurate prepolymer (p-TAC), initiator (Perbutyl 27 NOF (tl) and toluene were mixed and sufficiently stirred until a homogeneous solution was obtained to obtain a resin composition.

Next, the resin composition was impregnated into a glass cloth while keeping the temperature at 55°C or higher and dried to produce a resin cloth.

This resin cloth is laminated, copper foil is placed on both sides, 180
A MNJ plate was obtained by pressure molding at 50 kg/ad for 100 minutes.

Each of the obtained laminates was evaluated for dielectric constant, dielectric loss tangent, solder heat resistance, copper foil adhesive strength, and interlayer adhesive strength.

The results are shown in Table 1.

As is clear from the comparison with the later-described comparative example shown in Table 1, a laminate was obtained that had excellent high frequency characteristics and was also extremely excellent in copper foil adhesive strength and interlayer adhesive strength.

The dielectric constant and dielectric loss tangent were measured using IHH2'C'' as shown in FIGS. 1 and 2. In the figures, (a) shows the resin substrate, and (b) shows the metal foil.

Comparative Examples 1 to 2 As shown in Table 1, a laminate was produced in the same manner as in the above example using a resin composition containing no triallylisocyanurate prepolymer (Comparative Example 1).

In addition, a laminate was produced in the same manner as in the above Example using a resin composition having the same composition as in Example 2, except that the heat retention temperature of the resin composition was 25°C. 2).

The physical properties of the laminates Gkotsu~) obtained in Comparative Examples 1 and 2 were evaluated in the same manner. The results are also shown in Table 1. Compared to the example, the performance was much worse.

(Effects of the Invention) According to the present invention, a resin substrate with excellent high frequency performance can be obtained.

This high frequency resin substrate also has extremely excellent interlayer adhesion and metal foil adhesion.

Furthermore, this high-frequency resin substrate does not require conventional expensive components such as poly-4-fluoroethylene resin, so it can be manufactured at extremely low cost.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are a perspective view and a circuit diagram, respectively, showing a method for measuring a dielectric constant and a dielectric loss tangent.

Claims (6)

[Claims] (1) A high-frequency resin substrate characterized by being formed by molding or impregnating a base material with a resin composition containing polyphenylene oxide, a crosslinkable polymer and/or monomer, and a crosslinkable prepolymer while maintaining the temperature at 40°C or higher. . (2) The high frequency resin substrate according to claim (1), wherein the crosslinkable polymer is a styrene-butadiene copolymer and/or polystyrene. (3) The high frequency resin substrate according to claim (1), wherein the crosslinking monomer is triallyl isocyanurate and/or triallyl cyanurate. (4) The high frequency resin substrate according to claim (1), wherein the crosslinkable prepolymer is a triallyl isocyanurate prepolymer and/or a triallyl cyanurate prepolymer. (5) The resin composition is polyphenylene oxide 10
~70 parts by weight, styrene-butadiene copolymer and/or
or 30 parts by weight or less of polystyrene, triallyl isocyanurate and/or triallyl cyanurate 10
60 parts by weight, and 5 to 40 parts by weight of triallyl isocyanurate prepolymer and/or triallyl cyanurate prepolymer. (6) A high-frequency laminate formed by laminating and integrating the resin substrates according to claim (1).