JP2006169481A - Resin composition, prepreg, and laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition having less resin flow, being halogen free, and having good adhesiveness, a prepreg, and a laminate. <P>SOLUTION: The resin composition is used for forming a sheet-shaped prepreg through impregnation of a substrate with the resin composition. The resin composition contains a phenol aralkyl epoxy resin, a polyamide imide resin, and a hardening agent, and further contains a phosphate ester compound, and further contains a synthetic rubber, where the content of the hardening agent is 5 wt.% or more and 30 wt.% or less of the whole resin composition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin composition, a prepreg, and a laminate.

  The multilayer flexible circuit board includes a multilayer part and a flexible part. The flexible part extends to the multilayer part and constitutes the multilayer part. The flexible part is usually composed of at least one single-sided or double-sided flexible circuit board, and when there are a plurality of flexible parts, the flexible parts are often not bonded so as not to impair the flexibility. On the other hand, the multilayer part has a structure in which the layers are laminated and bonded via a prepreg.

  Up to now, prepreg has been used as an insulating base material for rigid circuit boards, and a resin flow during molding is relatively large in order to obtain superiority in thickness accuracy and voidless. If this is applied to a multilayer flexible circuit board as it is, a resin flow of a prepreg occurs from the multilayer part to the flexible part, resulting in disadvantages such as loss of flexibility after molding. Therefore, a non-flow prepreg with less resin flow is required for the multilayer flexible circuit board.

  In the case of a non-flow prepreg, an epoxy resin is often used, but in order to adjust the resin flow degree, the degree of cure of the epoxy resin is adjusted to increase the melt viscosity of the resin. In a resin system having a fast curing reaction, it is difficult to control the degree of curing, and there is a possibility that the adhesion to a substrate such as a polyimide film or a metal foil which is a counterpart during lamination adhesion may be reduced.

Moreover, although it was common to use brominated epoxy resin as a conventional flame-retardant adhesive (for example, Patent Documents 1 and 2), since there is a concern about the generation of dioxins during combustion, It is required that halogen is not included as a flame retardant.
JP 7-162113 A JP-A-10-212737

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resin composition, a prepreg, and a laminate that have a small resin flow, are halogen-free, and have excellent adhesion.

Such an object is achieved by the present invention described in the following (1) to (13).
(1) A resin composition used for impregnating a base material to form a sheet-like prepreg,
A resin composition comprising a phenol aralkyl epoxy resin, a polyamideimide resin, a curing agent, and a phosphate ester compound.
(2) Furthermore, the resin composition as described in said (1) containing synthetic rubber.
(3) The resin composition according to the above (1) or (2), wherein the content of the curing agent is 10% by weight or more and 25% by weight or less of the total resin composition.
(4) The resin composition according to any one of (1) to (3), wherein the curing agent includes a novolac type phenol resin having a triazine ring represented by the following compound (I).

(5) The resin composition according to the above (4), wherein the content of the novolak type phenol resin having a triazine ring is 5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the curing agent.
(6) The resin composition according to any one of (1) to (5) above, wherein an epoxy equivalent of the phenol aralkyl epoxy resin is 150 or more and 350 or less.
(7) The resin composition according to any one of (1) to (6), wherein the content of the phenol aralkyl epoxy resin is 45% by weight or more and 55% by weight or less of the total resin composition.
(8) The resin composition according to any one of (1) to (7), wherein the content of the polyamideimide resin is 5% by weight or more and 25% by weight or less of the total resin composition.
(9) The resin composition according to any one of (1) to (8), wherein the polyamideimide resin has a weight average molecular weight of 8000 to 15,000.
(10) The resin composition according to any one of (1) to (9), wherein a content of the phosphate ester compound is 10% by weight to 25% by weight of the total resin composition.
(11) The resin composition according to any one of (2) to (10), wherein the content of the synthetic rubber is 0.5 part by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the resin composition.
(12) A prepreg obtained by impregnating a base material with the resin composition according to any one of (1) to (11).
(13) A laminate comprising one or more of the prepregs described in (12) above.

  According to the present invention, it is possible to provide a resin composition, a prepreg, and a laminate that have a small resin flow, are halogen-free, and have excellent adhesion.

  Hereinafter, the resin composition, prepreg, and laminate of the present invention will be described in detail.

  The resin composition of the present invention is a resin composition used for impregnating a base material to form a sheet-like prepreg, and includes a phenol aralkyl epoxy resin, a polyamideimide resin, a curing agent, and a phosphate ester compound. It is characterized by.

  Moreover, the prepreg of the present invention is characterized in that a base material is impregnated with the above-mentioned resin composition.

  The laminate of the present invention is characterized in that one or more of the prepregs described above are laminated.

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

  In the resin composition of the present invention, a phenol aralkyl epoxy resin is used. Although the epoxy equivalent of the said epoxy resin is not specifically limited, It is preferable to use the phenol aralkyl epoxy resin of 150 equivalent or more and 350 equivalent or less. Compared to bisphenol-type epoxy resins, the skeleton is stiff and should be used when it is desired to obtain higher hardness. Although it does not specifically limit as a phenol aralkyl epoxy resin, If it hardens | cures using a novolak-type phenol resin at 25 degreeC, a higher heat-resistant effect and strong blade property can be acquired. If the epoxy equivalent is less than the lower limit, the compatibility may decrease. Moreover, when the said upper limit is exceeded, heat resistance may fall.

  Although content of the said epoxy resin is not specifically limited, 35 to 65 weight% of the whole resin composition is preferable, and 40 to 55 weight% is further more preferable. If it is less than the lower limit, the wettability with the object to be bonded may be lowered. Moreover, when the said upper limit is exceeded, resin flow control will become difficult and compatibility with a polyamidoimide resin may fall.

  In the resin composition of the present invention, a polyamideimide resin is used. The weight average molecular weight of the polyamideimide resin is not particularly limited, but it is preferably 8000 or more and 15000 or less. If the weight average molecular weight is less than the lower limit, the amount of seepage increases, and if the weight average molecular weight exceeds the upper limit, compatibility with the epoxy resin and impregnation into the substrate may decrease.

  The content of the polyamideimide resin is not particularly limited, but is preferably 5% by weight to 30% by weight, and more preferably 8% by weight to 20% by weight of the total resin composition. If the amount is less than the lower limit, the amount of seepage may increase. Moreover, when the said upper limit is exceeded, compatibility with an epoxy resin may fall.

  The polyamide-imide resin used in the present invention also has heat resistance and flame retardancy effects on its molecular skeleton.

  In the resin composition of the present invention, a curing agent is used.

  Although content of a hardening | curing agent is not specifically limited, 5 to 30 weight% of the whole resin composition is preferable, and 15 to 25 weight% is further more preferable. If it is less than the said lower limit, the chemical resistance and solvent resistance of the obtained hardened | cured material may fall. If the upper limit is exceeded, the curing agent that does not contribute to the reaction remains, so the resin flow may increase.

  Part of the curing agent is preferably a novolac type phenol resin represented by the following chemical formula.

  As the novolac type phenol resin, a novolac phenol type resin having a triazine ring is used. The triazine ring contains nitrogen and contributes to the flame retardant effect. It also has a primary amine, which contributes to the curing reaction of the epoxy resin.

  As a result, a multistage curing reaction is expected, the degree of curing can be easily controlled, and the resin flow can be suppressed without impairing adhesion.

  The content of the novolac type phenol resin is not particularly limited, but is preferably 5% by weight to 30% by weight, and more preferably 10% by weight to 22% by weight, based on the total amount of the curing agent. If it is less than the lower limit, the flame retardant effect of the triazine ring may be difficult to obtain, and if it exceeds the upper limit, a curing agent that does not contribute to the reaction remains, and the resin flow may increase.

  Although it does not specifically limit as another hardening | curing agent, A novolak-type phenol resin, a novolak-type cresol resin, amines, etc. are mentioned. Of these, amines are desirable.

  In the resin composition of the present invention, a phosphate ester compound is used. Thereby, the flame retardance in a prepreg single-piece | unit can be ensured. As mentioned above, brominated epoxy resins have generally been used as a flame retardant adhesive. However, there is concern about the generation of dioxins during combustion, and a halogen-free material is required. Examples of the flame retardant that achieves halogen-free include inorganic fillers such as aluminum hydroxide and magnesium hydroxide, phosphorus alone, and phosphorus-containing compounds. Inorganic fillers have a combustion retarding effect. In that respect, phosphorus alone and phosphorus-containing compounds have a fire extinguishing action. The content of the phosphoric acid ester compound is not particularly limited, but is preferably 10% by weight to 25% by weight and more preferably 12% by weight to 20% by weight of the total resin composition. If the amount is less than the lower limit value, the flame retardant effect may not be obtained. If the upper limit value is exceeded, the compatibility with the epoxy resin may be lowered or the adhesion may be lowered.

  The phosphoric ester compound used in the present invention has a high flame retardant effect on its molecular skeleton, and the contained resin composition retains good electrical characteristics.

  The resin composition of the present invention preferably contains a synthetic rubber. Thereby, resin flow control, adhesion improvement, and powder falling off during prepreg cutting can be prevented.

  The synthetic rubber is not particularly limited, and examples thereof include NBR, acrylic rubber, polybutadiene, isoprene, carboxylic acid-modified NBR, hydrogen conversion polybutadiene, and epoxy-modified polybutadiene. Among these, the solid type is more preferable than the liquid type because the workability during temporary bonding is improved.

  Further, a carboxylic acid-modified, hydroxyl-modified or epoxy-modified product for improving compatibility with an epoxy resin or polyamideimide, a hydrogen conversion type synthetic rubber or the like may be used to prevent thermal degradation.

  The content of the synthetic rubber is not particularly limited, but is preferably 0.5% by weight to 10% by weight, and more preferably 1% by weight to 5% by weight. If the amount is less than the lower limit, powder falling may occur or the resin flow may increase. If the upper limit is exceeded, the heat resistance is lowered and the linear expansion coefficient is increased, which may cause disconnection in the through hole of the interlayer connection used in the multilayer flexible circuit board.

  The resin composition of this invention can add additives other than the said component in the range which does not impair a characteristic as needed. Examples of the additive include an inorganic filler, a coupling material, an antifoaming material, and a leveling material.

  Next, the prepreg will be described.

  The prepreg of the present invention is obtained by impregnating a base material with the above resin composition. Thereby, it is possible to obtain a prepreg which is halogen-free and excellent in adhesion and has a small resin flow.

  Examples of the base material used in the present invention include glass fiber base materials such as glass fiber cloth and glass non-woven cloth, or inorganic fiber base materials such as fiber cloth and non-fiber cloth containing inorganic compounds other than glass, aromatic polyamide resins, polyamides. Examples thereof include organic fiber base materials composed of organic fibers such as resins, aromatic polyester resins, polyester resins, polyimide resins, and fluororesins. Among these base materials, glass fiber base materials represented by glass woven fabric are preferable in terms of strength and water absorption.

  Examples of the method of impregnating the base material with the resin composition obtained in the present invention include a method of immersing the base material in a resin varnish, a method of applying with various coaters, and a method of spraying with a spray. Among these, the method of immersing the base material in the resin varnish is preferable. Thereby, the impregnation property of the resin composition with respect to a base material can be improved. In addition, when a base material is immersed in a resin varnish, a normal impregnation coating equipment can be used.

  The solvent used for the resin varnish is selected from those having good solubility in the resin composition, and those that do not remain in the adhesive when dried after the resin composition is impregnated into the substrate. It is preferable. For example, acetone or methyl ethyl ketone, xylene, mesitylene, n-hexane, methanol, ethanol, ethyl cellosolve, butyl cellosolve, hexyl cellosolve, butyl cellosolve acetate, methoxypropanol, cyclohexanone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, or the like. It is possible to use mixed systems of more than one species.

  Although the solid content of the resin varnish is not particularly limited, the solid content of the resin composition is preferably 10% by weight to 60% by weight, and particularly preferably 15% by weight to 45% by weight. Thereby, the impregnation property to the base material of a resin varnish can further be improved. A prepreg can be obtained by impregnating the base material with the resin composition and drying at a predetermined temperature, for example, 80 ° C. or higher and 200 ° C. or lower.

  Next, a laminated board is demonstrated.

  The laminate of the present invention is formed by molding at least one prepreg described above. In the case of a single prepreg, a metal foil or film is stacked on both upper and lower surfaces or one surface. Two or more prepregs can be laminated. When two or more prepregs are laminated, a metal foil or film is laminated on the outermost upper and lower surfaces or one surface of the laminated prepreg. Next, a laminate can be obtained by heating and pressurizing a laminate of a prepreg and a metal foil. The heating temperature is not particularly limited, but is preferably 120 ° C. or higher and 220 ° C. or lower, and particularly preferably 150 ° C. or higher and 200 ° C. or lower. Moreover, the pressure to pressurize is not particularly limited, but is preferably 0.5 MPa or more and 4 MPa or less, and particularly preferably 1.0 MPa or more and 3.5 MPa or less. Thereby, the laminated board with high thickness accuracy and excellent moldability can be obtained. The resin composition in the present invention uses a higher polymer resin and has a high melt viscosity. Therefore, it is possible to reduce the resin flow-out due to the press or roll, and to increase the thickness accuracy.

  Examples of the metal constituting the metal foil include copper and a copper alloy, aluminum and an aluminum alloy, iron and an iron alloy, and the like. Examples of the film include polyethylene and polypropylene.

A multilayer flexible circuit board can be obtained by using the prepreg obtained as described above as an interlayer adhesive of the flexible circuit board.
Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

Example 1
As resin composition, phenol aralkyl epoxy resin (epoxy equivalent 274, Nippon Kayaku Co., Ltd. NC3000H) 50% by weight, polyamideimide resin (molecular weight 10,000, Tg = 280 ° C., Toyobo Co., Ltd.) 11% by weight, as curing agent , Diaminodiphenyl sulfone (Mitsui Chemicals Fine Co., Ltd., 3, `3-DAS) 18% by weight, novolac type triazine phenol resin (OH equivalent 125, Dainippon Ink and Chemicals Phenolite LA-7054) 4% by weight In addition, 15% by weight of phosphoric ester amide (P content 10%, developed by Shikoku Kasei Co., Ltd.) is blended as an additive, and 2% by weight of carboxyl group-containing acrylonitrile butadiene rubber (Nippon Nippon Corporation 1072J) is blended. Non-volatile in mixed solvent with butyl cellosolve and N-methylpyrrolidone Min and the mixture was stirred so as to be 30% to 40%. The resin varnish was impregnated into a 88 μm thick glass cloth and dried at 190 ° C. for 5 minutes to obtain a prepreg.
The obtained printed circuit board prepreg was subjected to thermocompression molding at 190 ° C. and 1.5 MPa for 2 hours on a polyimide surface of a single-sided copper-clad laminate by a vacuum press to obtain a substrate for evaluation.
(Example 2)
Except that the amount of the phenol aralkyl epoxy resin was 45% by weight, the amount shown in Table 1 was used, and an evaluation substrate was obtained in the same manner as in Example 1 and evaluated in the same manner.
(Example 3)
Except that the amount of the phenol aralkyl epoxy resin was 55% by weight, the amount shown in Table 1 was used, and an evaluation substrate was obtained in the same manner as in Example 1 and evaluated in the same manner.
Example 4
Except for using 10 parts by weight of the novolak-type phenol having a triazine ring as a curing agent for 100 parts by weight of the total curing agent, the amounts shown in Table 1 were used. Obtained and evaluated in the same manner.
(Example 5)
Except for using 25 parts by weight of the novolac-type phenol having a triazine ring as the curing agent for 100 parts by weight of the total curing agent, the amounts shown in Table 1 were used. Obtained and evaluated in the same manner.
(Example 6)
An evaluation substrate was obtained in the same manner as in Example 1 except that the amount of the polyamideimide resin was changed to 5% by weight, and evaluated in the same manner.
(Example 7)
Except that the blending amount of the polyamideimide resin was 25% by weight, the blending amounts shown in Table 1 were used, and an evaluation substrate was obtained in the same manner as in Example 1 and evaluated in the same manner.
(Example 8)
An evaluation substrate was obtained in the same manner as in Example 1 except that the amount of phosphoric ester amide was changed to 10% by weight, and evaluated in the same manner.
Example 9
Except that the blending amount of phosphoric ester amide was 25% by weight, the blending amount shown in Table 1 was used, and an evaluation substrate was obtained in the same manner as in Example 1 and evaluated in the same manner.
(Example 10)
Except that the blending amount of the carboxyl group-containing acrylonitrile butadiene rubber was 0.5 wt%, the blending amount shown in Table 1 was used, and an evaluation substrate was obtained in the same manner as in Example 9, and evaluated in the same manner.
(Example 11)
Except that the blending amount of the carboxyl group-containing acrylonitrile butadiene rubber was 10% by weight, the blending amounts shown in Table 1 were used, and an evaluation substrate was obtained in the same manner as in Example 9 and evaluated in the same manner.
(Comparative Example 1)
The same as Example 1 except that a phenol aralkyl epoxy resin having an epoxy equivalent of 274 was not used and a cresol novolac type epoxy resin (epoxy equivalent 200, Dainippon Ink & Chemicals, Inc. N-655-EXP-S) was used. Thus, an evaluation substrate was obtained and evaluated in the same manner.
(Comparative Example 2)
An evaluation board was obtained and evaluated in the same manner as in Example 1 except that a phenoxy resin (epoxy equivalent 7800, Japan Epoxy Resin Co., Ltd. JER-1256B40) was used without using a polyamideimide resin.
(Comparative Example 3)
An evaluation board was obtained in the same manner as in Example 1 except that the polyamideimide resin was not used, and was similarly evaluated.

The evaluation substrate thus obtained was measured and evaluated for the resin flow amount, powder falling at the time of cutting, moisture-absorbing solder heat resistance, adhesion, electrical insulation and flame retardancy, and the results are shown in Tables 2 to 4.

* Resin Flow After thermocompression molding, the resin part that exudes from the edge of the glass cloth was measured with a metal microscope. (N = 20)
* Impregnation into glass cloth The compatibility of the resin composition, the impregnation property of the resin composition into the glass cloth, and whether there were any abnormalities such as foaming after drying were confirmed by appearance.
* Powder fall at the time of cutting It was visually judged whether or not powder fall occurred at the time of cutting by the ring cutter or the big punch before and after the prepreg molding.
* Hygroscopic solder heat resistance Conforms to JIS standard C5016-10.3. It was confirmed that there was no swelling or peeling.
* Adhesive strength Conforms to JIS standard C5016-8.1.
* Electrical insulation

Conforms to JIS standard K6911. Measure the cured product.
* Incombustibility Complies with UL standard UL94V.

  In recent years, as electronic devices have become smaller, lighter, and higher in density, printed circuit board high-density and high-fine circuit patterns have been required. In order to solve this problem, multilayer flexible printed circuit boards in which flexible printed circuit boards are laminated have been manufactured. The multilayer flexible printed circuit board is a printed circuit board having a conductor pattern in three or more layers including the surface conductor layer. The surface conductor circuit is referred to as an outer layer circuit, and the conductor layer in the insulating layer is referred to as an inner layer circuit. The multilayer flexible printed circuit board is made from an inner layer circuit board obtained by processing a printed circuit board and a base material such as glass cloth or non-woven fabric, impregnated with resin to make a semi-cured state, from a metal foil or printed circuit board used as an outer layer circuit It can be obtained by sandwiching this between metal plates and applying heat and pressure to cure and mold the prepreg. Through the prepreg, electrical connection between conductors of different layers is performed by through-hole plating. INDUSTRIAL APPLICABILITY The present invention is used for a prepreg for a multilayer flexible printed circuit board that has a small resin flow and is excellent in moldability and heat resistance when laminated by heating and pressing.

Claims (13)

A resin composition used for impregnating a base material to form a sheet-like prepreg,
A resin composition comprising a phenol aralkyl epoxy resin, a polyamideimide resin, a curing agent, and a phosphate ester compound.   Furthermore, the resin composition of Claim 1 containing synthetic rubber.   The resin composition according to claim 1 or 2, wherein the content of the curing agent is 10 wt% or more and 25 wt% or less of the total resin composition. The resin composition according to any one of claims 1 to 3, wherein the curing agent contains a novolak-type phenol resin having a triazine ring represented by the following compound (I).

  5. The resin composition according to claim 4, wherein the content of the novolac type phenol resin having a triazine ring is 5 parts by weight or more and 30 parts by weight or less with respect to 100 parts by weight of the curing agent.   The resin composition according to any one of claims 1 to 5, wherein an epoxy equivalent of the phenol aralkyl epoxy resin is 150 or more and 350 or less.   7. The resin composition according to claim 1, wherein the content of the phenol aralkyl epoxy resin is 45% by weight or more and 55% by weight or less of the total resin composition.   8. The resin composition according to claim 1, wherein the content of the polyamideimide resin is 5% by weight or more and 25% by weight or less of the total resin composition.   The resin composition according to any one of claims 1 to 8, wherein the polyamideimide resin has a weight average molecular weight of 8000 or more and 15000 or less.   10. The resin composition according to claim 1, wherein the content of the phosphate ester compound is 10% by weight or more and 25% by weight or less of the total resin composition.   The resin composition according to any one of claims 2 to 10, wherein a content of the synthetic rubber is 0.5 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the resin composition.   A prepreg obtained by impregnating a base material with the resin composition according to claim 1.   A laminate obtained by laminating one or more prepregs according to claim 12.