JP3339301B2 - Epoxy resin composition, prepreg using this resin composition, and laminate using this prepreg - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin composition, a prepreg using the resin composition, and a laminate using the prepreg. For example, the present invention relates to a laminate used for a printed circuit board used in a high frequency region, The present invention relates to a prepreg used for producing the laminate, and an epoxy resin composition useful for producing the prepreg.

[0002]

2. Description of the Related Art Epoxy resin, epoxy resin curing agent,
A laminate in which a cured product of polyphenylene ether and a glass cloth are integrated has been already known in 1970. This type of polyphenylene ether (hereinafter referred to as PPE
-A laminated board made of a cured product of an epoxy resin-based thermosetting resin is used in a satellite communication wave region in that it has excellent high-frequency characteristics, particularly, dielectric constant and dielectric loss tangent characteristics. It is suitable for the X band (10 GHz) region. When a cured product of a PPE-epoxy resin-based thermosetting resin constituting a laminated board of this type proposed so far is classified, it can be classified into three types of cured products. One is a cured product in which the epoxy resin and the PPE are present independently of each other by simply blending the PPE with the epoxy resin. The other is a PPE in which the epoxy group of the epoxy resin is reacted with the terminal hydroxyl group of the PPE. A cured product of a modified epoxy resin, and another cured product of a PPE-modified epoxy resin obtained by reacting an epoxy resin with a low-molecular-weight PPE by using a radical initiator as a radical initiator are known. When the first cured product is subjected to an alkali resistance test in which the laminate is immersed in a 10% aqueous solution of sodium hydroxide, since the epoxy resin and PPE are not bonded, the cured product lacks water resistance and causes delamination. According to the following method, when the PPE to be charged is a polymer, the reactivity between the terminal phenolic hydroxyl group of the PPE and the epoxy group of the epoxy resin is low, and therefore, a large amount of unreacted PPE not involved in the crosslinked structure is present in the cured product. Therefore, the interlayer adhesive strength is low. According to the last method, a low-molecular P activated by a redistribution reaction of a high-molecular-weight PPE by a radical initiator is used.
PE is formed, and the addition reaction of the phenolic hydroxyl group of the phenolic compound bound to the PPE with the epoxy group of the epoxy resin causes the PPE to participate in the crosslinked structure in the cured product. Although the laminate manufactured using the resin composition of the first party causes delamination, the phenomenon of delamination is not observed.

In other words, comparing the chemical structures of the epoxy resins constituting the cured product, the final cured product is composed of a substance having a high crosslinking density different from the former two and has excellent characteristics, but is still copper. There is room for improvement in the adhesive strength to the foil, heat resistance, and electrical properties.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture a laminate having excellent adhesive strength to copper foil, heat resistance, and electrical characteristics. An epoxy resin composition useful for the present invention, a prepreg using the epoxy resin composition, and a laminate using the prepreg.

[0005]

Means for Solving the Problems] claims 1 to請 of the present invention
The epoxy resin composition according to claim 5 , which has a number average molecular weight of 1
A modified phenol product obtained by redistributing a 0000-30000 high molecular weight polyphenylene ether and a phenolic compound in the presence of a radical initiator, an epoxy resin,
The epoxy resin curing agent and an inorganic powder having a dielectric constant of 100 or more and an average particle diameter of 0.1 to 100 μm are used as components. As the radical initiator, for example, benzoyl peroxide can be used. The modified phenol product preferably has a number average molecular weight of 1,000 to 3,000, and the inorganic powder is 1 to 300 parts by weight based on 100 parts by weight of the total of the modified phenol product, the epoxy resin, and the curing agent of the epoxy resin. Parts by weight are preferred, and titanium dioxide-based ceramics can be used as the inorganic powder,
The phenolic compound is a compound having two or more phenolic hydroxyl groups in the molecule, and has a high adhesive strength to a metal foil, and is an index of high frequency characteristics, and is excellent in dielectric constant and dielectric tangent. It is useful.

A prepreg according to a sixth aspect of the present invention is a prepreg obtained by forming the above epoxy resin composition into a resin varnish using an organic solvent, and impregnating and drying the resin varnish on a substrate. This is a prepreg useful for the production of a laminate having high adhesive strength and excellent in dielectric constant and dielectric loss tangent which are indicators of high frequency characteristics.

[0007] The laminate according to claim 7 of the present invention comprises:
The above prepreg and metal foil are heated and pressed, the adhesive strength with copper foil is high, the dielectric constant which is an index of high frequency characteristics,
It has excellent dielectric loss tangent.

Hereinafter, embodiments of the present invention will be described in detail.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is:
There are no particular restrictions on the epoxy resin used for the laminate, and examples thereof include bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and bisphenol-type epoxy resin.
S-type epoxy resin, phenol-novolak type epoxy resin, cresol novolak type epoxy resin, isocyanurate type epoxy resin, hydantoin type epoxy resin, alicyclic epoxy resin, biphenyl type epoxy resin,
And polyfunctional epoxy resins and the like, and these may be used alone or in combination. Further, flame-retardant epoxy resins obtained by brominating these resins can also be used.

[0010] As a curing agent for these epoxy resins,
Commonly used amines such as primary and secondary amines, phenols such as bisphenol A and bisphenol F,
Acid anhydrides can be mentioned. These may be used alone or in combination.

For the curing reaction of the epoxy resin, it is practical to add, for example, an imidazole-based curing accelerator as required.

The epoxy resin composition of the present invention relates to a redistribution reaction between a high-molecular-weight polyphenylene ether having a number average molecular weight of 10,000 to 30,000 and a phenolic compound in the presence of a radical initiator, as being involved in the crosslinked structure of the epoxy resin. Containing modified phenol product. A typical example of the polyphenylene ether is poly (2,6-dimethyl-1,4phenylene oxide). Such a polyphenylene ether can be produced, for example, by a synthesis method disclosed in the specification of US Pat. No. 4,059,568.
As the phenolic compound, polyfunctional phenols having two or more phenolic hydroxyl groups in the molecule, such as polyphenol bisphenol A, phenol novolak, and cresol novolak, are preferable. Examples of the radical initiator include, in addition to benzoyl peroxide, dicumyl peroxide, tert-butylcumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-tert-butylperoxy. Hexin-
3,2,5-dimethyl-2,5-di-tert-butylperoxyhexane, α · α′-bis (tert-butylperoxy-m-isopropyl) benzene [1.4
(Or also referred to as 1.3) -bis (tert-butylperoxyisopropyl) benzene]. In addition, although it is not a peroxide as an initiator, a commercially available initiator “Biscumyl” (trade name, manufactured by NOF CORPORATION) (1 minute half-life temperature 330 ° C.) can also be used. Number average molecular weight of 1000 in the presence of a radical initiator
When a high molecular weight polyphenylene ether of 0 to 30,000 is reacted with a phenolic compound in a solvent such as toluene or chloroform, the high molecular weight polyphenylene ether is first radicalized, and the redistribution reaction of a low-molecular-weight polyphenylene ether whose straight chain is cut is performed. Proceeds, and phenols are modified by the polyphenylene ether. The redistribution reaction is performed in an aromatic hydrocarbon solvent such as toluene, benzene, or xylene by heating at 80 to 120 ° C. for 10 to 100 minutes.
The low molecular weight polyphenylene ether having a straight chain cut is preferably one having a number average molecular weight in the range of 1,000 to 3,000. That is, if it exceeds 3,000, the melt viscosity increases, and if it is less than 1,000, the mechanical strength and heat resistance of the laminate tend to decrease. The appropriate amount of benzoyl peroxide is 3 to 20 parts by weight and the amount of the phenolic compound is 3 to 20 parts by weight based on 100 parts by weight of PPE. That is, when the added amount of benzoyl peroxide and the phenolic compound is excessive, the number average molecular weight of the low molecular weight polyphenylene ether is reduced, and the mechanical strength and heat resistance are reduced as described above. It does not proceed and the number average molecular weight does not decrease. As a result PP
E does not participate in the crosslinked structure constituting the cured product of the epoxy resin and remains in a free form.

The modified phenol product is composed of a substance in which one or two phenolic compounds are bonded to the terminal of a low-molecular-weight PPE, and thus the phenolic compound phenol is formed. PPE participates in the crosslinked structure of the cured product because the residue consisting of the hydroxyl group reacts with the epoxy group of the epoxy resin.

Further, the inorganic powder added as an inorganic filler has a dielectric constant of 100 or more and an average particle diameter of 0.1 to 0.1.
100 μm powder, which contributes to the improvement of the electrical properties. In particular, when the average particle size is smaller than 0.1 μm, the dispersibility is poor, and the particles tend to be unevenly distributed. The inorganic filler may be, for example, a titanium dioxide ceramic, a barium titanate ceramic, a lead titanate ceramic, a strontium titanate ceramic, a calcium titanate ceramic, a bismuth titanate ceramic,
It is added in combination of one or more of magnesium titanate-based ceramics and lead zirconate-based ceramics.

The mixing ratio will be described. The solid content of the epoxy resin and the curing agent of the epoxy resin is 50 to 50.
The number average molecular weight is 10,000 to 3 with respect to 95% by weight.
Preferred is 5 to 50% by weight of a modified phenol product obtained by redistributing 0000 high molecular weight polyphenylene ether and a phenolic compound in the presence of a radical initiator.

To prepare a resin varnish containing these components, solvents such as toluene, xylene, benzene, ketone and alcohols are used.

Next, the prepreg obtained by impregnating and drying the substrate with the resin varnish can be generally prepared by the following method. By immersing the substrate in a resin varnish,
The substrate is impregnated with these resin varnishes and adhered. The resin content of the prepreg thus produced is not particularly limited, but is preferably 30 to 70% by weight.

At the time of impregnation, the resin varnish is
When the temperature is kept at 5 ° C., the resin varnish can be kept stable, the impregnation property to the base material can be kept constant, and the characteristics of the laminate can be improved. In heating and drying after impregnating the resin varnish, a temperature of 80 to 180 ° C is preferable. If the heating and drying is insufficient, only the surface of the prepreg stops drying, and the solvent remains inside, so that distortion occurs due to a difference in the concentration of the resin between the surface and the inside of the prepreg, and the prepreg surface is Fine cracks occur. In addition, when excessive heating and drying, the prepreg surface undergoes a sharp change in viscosity during the drying process, causing uneven streaks and resin dripping on the prepreg surface, resulting in uneven adhesion between the metal foil and the prepreg. Large and small irregularities in the peel strength, solder heat resistance and dielectric properties of the metal foil occur.

The substrate includes glass cloth, aramid cloth, polyester cloth, pulp paper, linter paper and the like.

A predetermined number of prepregs and metal foils thus produced are laminated to form a pressure-receiving body, and the pressure-receiving body is heated and pressed to obtain a laminated plate. As the metal foil, a copper foil, an aluminum foil or the like is used. Pressing is performed for joining the metal foil and sheet and adjusting the thickness, so that the pressing conditions can be selected as necessary. In addition, since the crosslinking reaction between the modified phenol product modified by PPE, the epoxy resin, and the curing agent of the epoxy resin mainly depends on the reaction temperature of the curing agent, the heating temperature and the heating time are selected according to the type of the curing agent. Good. For example, generally, a temperature of 150 to
300 ° C., pressure 50 kg / cm ² , time about 10 to 60 minutes.

The metal foil-clad laminate thus obtained does not impair the properties of the epoxy resin and the PPE, has excellent high-frequency properties such as dielectric properties, and has heat resistance and adhesive strength which affect solder heat resistance. The processability such as through holes and punching due to the strength and the reliability of circuit formation due to the etching property are also excellent.

The epoxy resin composition of the present invention is not limited to an example of use as a prepreg by forming a resin varnish through a solvent, impregnating the resin varnish into a substrate such as glass cloth and drying the resin varnish. A sheet containing no base material can be prepared by the method, and this sheet can be used as a prepreg. When the casting method is used, for example, a resin varnish is applied to a sheet insoluble in the solvent of the resin varnish, such as a polyester film or a polyimide film, to a thickness of 5 to 700 μm, and when sufficiently dried, the blended resin is heated. It is excellent in that a sheet can be formed more easily at a relatively low temperature as compared with the case of extrusion molding which melts. The above-mentioned sheet for casting the resin varnish is practical because the use of a sheet surface-treated with a release agent facilitates peeling.

Hereinafter, embodiments of the present invention will be specifically described with reference to examples. (Preparation of PPE solution) First, Japan G.P. E. FIG. 100 parts by weight (hereinafter referred to as “parts”) of 640-111 manufactured by Plastics Co., Ltd., the ratio (unit: weight) of toluene to benzoyl peroxide and phenolic compound bisphenol A shown in Table 3 PPE solution (A) (B) (C) (D) consisting of a modified phenol product modified by PPE by redistribution and stirring at 90 ° C. for 60 minutes.
(E) and (F) were obtained in solution. This solution was subjected to gel permeation chromatography (column composition: SuperHM-M manufactured by Tosoh Corporation).
(1) + SuperHM-H (1) The molecular weight distribution was measured, and (Table 3) shows the number average molecular weight of each PPE solution.

[0024]

【Example】

(Examples 1 to 8) PPE solution (A) shown in Table 3
(B) Using (C), excluding the inorganic powder (inorganic filler), put the components shown in (Table 1) into a separable flask, stir at room temperature for 30 minutes, air-cool, and perform a resin liquid at 25 ° C. I got Titanium oxide (product number: TR-840, average particle size: 0.3 μm) manufactured by Fuji Titanium Industry Co., Ltd. was added as an inorganic powder to the resin solution, and then 1000 to 1500 using a disper.
Stirred at rpm for 5 minutes. Then 1 in the basket mill
After stirring for an hour, a resin varnish containing the epoxy resin composition of the present invention as a component was obtained. As the epoxy resin, a brominated bisphenol A type epoxy resin manufactured by Toto Kasei Co., Ltd. was used.

This varnish had a low initial viscosity, had no precipitation phenomenon, and had excellent storage stability. After 24 hours, a 0.1 mm E glass cloth was impregnated with a resin varnish,
After drying for 5 minutes, a prepreg having a resin content of 65% by weight was obtained. As shown in (Table 2), this prepreg had a smooth surface and no unevenness in impregnation of the resin, and confirmed the good impregnation of the resin varnish.

Further, copper foil of 18 μm is arranged on both sides of the prepreg to form a pressure-receiving body.
The mixture was heated and pressed at 100 cm ² for 100 minutes to obtain a copper-clad laminate having copper foil laminated on both sides. The peel strength (peeling strength of copper foil), solder heat resistance, dielectric constant, and dielectric loss tangent of this laminated plate were measured, and the results are shown in Table 2. Note that the dielectric constant,
The dielectric loss tangent and the dielectric loss tangent were based on measurement conditions specified in MIL.

[0027]

[Comparative example]

(Comparative Examples 1 to 3) PPE solution (D) shown in Table 3
(E) A resin varnish was obtained in the same steps as in the examples using (F) and the compounding ratios shown in Table 1, and a laminated board was obtained using the resin varnish in the same manner as in the examples.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

Comparing the resin varnish characteristics, prepreg characteristics, and laminate characteristics of the example and the comparative example, it is clear that the resin varnish has particularly excellent peeling strength, dielectric constant, and dielectric loss tangent characteristic. The impregnation property is due to the fact that PPE contributes to the crosslinked structure constituting the cured product of the epoxy resin.

[0032]

According to the epoxy resin composition, prepreg and laminate of the present invention, the adhesive strength to copper foil, heat resistance,
In addition, a laminate having excellent electrical characteristics can be provided.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Eiichiro Saito 1048 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-4-132730 (JP, A) JP-A-3-166934 ( JP, A) JP-A-1-190448 (JP, A) JP-A-3-2775761 (JP, A) JP-A-3-166935 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) C08G 59/62 B32B 27/38 C08J 5/24 C08K 3/22 C08L 63/00-63/10

Claims (7)

(57) [Claims] 1. A number average molecular weight of 10,000 to 3000.
Number average of redistribution reaction between high molecular weight polyphenylene ether and phenolic compound in the presence of a radical initiator
Modified phenol product having a molecular weight of 1,000 to 3,000, an epoxy resin, a curing agent for the epoxy resin, and a dielectric constant of 100 or more and an average particle size of 0.1 to 100 μm
An epoxy resin composition characterized by comprising an inorganic powder as a component. 2. The epoxy resin composition according to claim 1, wherein the radical initiator is benzoyl peroxide. 3. The method according to claim 1, wherein the amount of the inorganic powder is 1 to 300 parts by weight based on 100 parts by weight of the total of the modified phenol product, the epoxy resin, and the curing agent for the epoxy resin.
Or the epoxy resin composition of claim 2 . 4. The epoxy resin composition according to claim 1, wherein said inorganic powder is a titanium dioxide-based ceramic. 5. A method according to claim 1 to claim said phenolic compound having two or more phenolic hydroxyl groups in the molecule
4. Any one of the epoxy resin compositions. 6. A prepreg obtained by forming a resin varnish from the epoxy resin composition according to claim 1 using an organic solvent, and impregnating and drying the resin varnish on a substrate. 7. A laminate obtained by laminating a metal foil on the prepreg according to claim 6 and heating and pressing.