JP2002254543A - Composite laminated sheet and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the solder heat resistance of a composite laminated sheet having a core layer resin containing aluminum hydroxide as an inorganic filler. SOLUTION: A surface layer resin extends to a core layer in a state connected to a surface layer to constitute the composite laminated sheet wherein resin sumps distributed in the core layer are formed. This composite laminated sheet is manufactured by subjecting a surface layer prepreg, which is adjusted so that the lowest melt viscosity of the resin at the time of heating press molding becomes 50-500 Pa.s, and a core layer prepreg, which is adjusted so that the lowest melt viscosity of the resin at the time of heating press molding becomes higher than that of the surface layer prepreg, to heating press molding. The core layer prepreg is formed so as to leave gaps in which the resin of the prepreg at the time of heating press molding can flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a glass fiber nonwoven substrate comprising an epoxy resin composition containing at least aluminum hydroxide as an inorganic filler and a surface layer holding the epoxy resin composition on a glass fiber woven substrate. The present invention relates to a composite laminate in which a held core layer is integrated by heating and pressing. The present invention also relates to a method for producing the composite laminate.

[0002]

2. Description of the Related Art The above composite laminate is widely used as an insulating layer of a printed wiring board, and aluminum hydroxide of a core layer is blended for the purpose of imparting flame retardancy. Aluminum hydroxide starts to thermally decompose at a high temperature (around 200 ° C.) and generates water vapor to exhibit a flame-retardant effect. However, if this thermal decomposition temperature is low, the heat resistance (solder heat resistance) of the laminate decreases. This can cause

[0003] The thermal decomposition onset temperature of aluminum hydroxide varies depending on the production conditions of aluminum hydroxide, and the lower the content of sodium oxide in the produced aluminum hydroxide, the higher the thermal decomposition onset temperature. In industrial aluminum hydroxide, the content of sodium oxide in aluminum hydroxide is an indicator of heat resistance. In high heat-resistant applications, the content of sodium oxide is approximately 0.1% by mass.
It is managed below.

[0004] The solder heat resistance required for a composite laminate for the manufacture of a printed wiring board is such that a test piece floats in a solder bath at 260 ° C for 20 seconds or more without any abnormality according to the standard defined by JIS. Is considered 120
It has been operated for nothing more than seconds. Under such circumstances, aluminum hydroxide used in the core layer resin of the composite laminate is a high heat-resistant aluminum hydroxide. In particular, aluminum hydroxide of 30% by mass or more is contained in the core layer resin. In such a case, it is necessary to select aluminum hydroxide having high heat resistance. In such a case, when a general-purpose aluminum hydroxide having a sodium oxide content exceeding 0.1% by mass is employed, the solder heat resistance becomes less than 120 seconds.

[0005]

The problem to be solved by the present invention is to improve the solder heat resistance of a composite laminate containing at least aluminum hydroxide as an inorganic filler in the resin of the core layer. is there. In the case of using aluminum hydroxide having a high heat resistance in which the amount of sodium oxide contained as an impurity is restricted, the solder heat resistance of a conventional composite laminate employing the same aluminum hydroxide is further improved. Further, even when aluminum hydroxide for general use containing an increased amount of sodium oxide as an impurity is used, the solder heat resistance of the conventional composite laminate using aluminum hydroxide having high heat resistance is brought close to the heat resistance.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a glass fiber woven fabric base material and an epoxy resin composition containing at least aluminum hydroxide as an inorganic filler. It is intended for a composite laminate in which a core layer held by a material is integrated by heating and pressing. In order to solve the above-described problems, the composite laminate according to the present invention has a configuration in which the surface layer resin extends to the core layer in a state of being connected to the surface layer, and forms a resin pool distributed in the core layer. Features.

[0007] The composite laminate having such a structure is as follows.
A prepreg obtained by impregnating an epoxy resin composition into a glass fiber woven fabric substrate and drying by heating is used as a surface layer, and an epoxy resin composition containing at least aluminum hydroxide as an inorganic filler is impregnated into a glass fiber nonwoven fabric substrate. The prepreg obtained by heating and drying is used as a core layer of the surface layer, and manufactured by a method in which these are integrated by heat and pressure molding. The surface layer prepreg and the core layer prepreg are adjusted and used as follows. That is, the surface layer prepreg is adjusted so that the minimum melt viscosity of the resin at the time of the heat and pressure molding is 50 to 500 Pa · s. The core layer prepreg is adjusted so that the minimum melt viscosity of the resin at the time of the hot press molding is higher than the minimum melt viscosity of the surface layer prepreg. In addition, the core layer prepreg is left with a void through which the resin of the prepreg melted at the time of the heat and pressure molding can flow.

In the composite laminate manufactured as described above, since the minimum melt viscosity of the surface layer prepreg resin at the time of heating and pressing is low, the resin flows into the voids of the core layer prepreg to form a resin reservoir. Becomes The resin pool extends to the core layer with the surface layer resin connected to the surface layer and is distributed in the core layer, and usually has a size of 100 μm or more. The minimum melt viscosity of the surface layer prepreg resin is low as described above, while the minimum melt viscosity of the core layer prepreg resin is higher than the minimum melt viscosity of the surface layer prepreg resin. Will be formed.

Due to the formation of the above-mentioned resin pool, the adhesion area between the surface layer and the core layer increases. Further, the interlayer adhesion strength between the surface layer and the core layer is improved by the anchor effect of the resin pool. From these results, even when aluminum hydroxide is thermally decomposed to generate water vapor, delamination between the surface layer and the core layer is less likely to occur, and heat resistance is improved.

If the minimum melt viscosity of the surface layer prepreg resin is too low, it is difficult to control the thickness accuracy of the laminate, and if the minimum melt viscosity is too high, the resin pool will not be formed well.

[0011]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, aluminum hydroxide for general use containing more than 0.1% by mass of sodium oxide as an impurity can be employed. In the same manner as in the case of adopting the above, the solder heat resistance of the composite laminate can be ensured. Since aluminum hydroxide for general use can be adopted, material cost can be reduced. However, the sodium oxide content in the aluminum hydroxide is preferably controlled to 0.2% by mass or less. Of course, in the present invention, when aluminum hydroxide having a high heat resistance is employed, the solder heat resistance of a conventional composite laminate employing the same aluminum hydroxide having a high heat resistance can be further improved. In addition to aluminum hydroxide as an inorganic filler, a commonly used inorganic filler such as talc may be added to the core layer resin. The content of aluminum hydroxide in the core layer resin is preferably 20 to 40% by mass from the viewpoint of imparting flame retardancy and securing heat resistance.

As described above, a surface layer prepreg produced by impregnating a glass fiber woven fabric substrate with an epoxy resin composition and heating and drying the resin has a minimum melt viscosity of the resin in the heat and pressure molding for producing a composite laminate. From 50 to 500 Pa
Adjust to s. On the other hand, the minimum melt viscosity of the resin of the core layer prepreg is set higher than the minimum melt viscosity of the resin of the surface layer prepreg.
It is preferable to adjust in the range of 05 MPa · s. The adjustment of these minimum melt viscosities is performed by changing the degree of heating and drying at the time of prepreg production. In order to allow the molten resin to flow into the voids of the core layer prepreg during the heat and pressure molding of the composite laminate, the resin content of the core layer prepreg (including the inorganic filler) should be 95% by mass or less. Then, the glass fiber nonwoven fabric substrate is preferably impregnated with the epoxy resin composition.

The surface layer prepreg and the core layer prepreg as described above are manufactured by a standard composite laminate manufacturing method.

[0014]

EXAMPLES Examples according to the present invention, comparative examples, and conventional examples will be described below. Examples 1 to 5, Comparative Example 1 and Conventional Examples 1 to 2 A glass fiber woven fabric substrate was impregnated with an epoxy resin composition containing no inorganic filler, dried by heating, and dried to form a surface layer prepreg (resin content: 45% by mass). ) Manufactured. An epoxy resin composition containing 30% by mass of aluminum hydroxide and 27% by mass of talc as an inorganic filler is impregnated into a glass fiber nonwoven fabric substrate and dried by heating to form a core prepreg (containing a resin containing an inorganic filler). 90% by mass). One sheet of the surface layer prepreg is placed on both sides of the two-ply core layer prepreg, and 35 μm thick copper foil is placed on the outermost surface, and these are heated and pressed to form a 1.6 mm thick composite laminate. And

Table 1 shows the minimum melt viscosity of the resin when the surface layer prepreg used in each of the above examples was heated and pressed. The adjustment of the minimum melt viscosity is performed by changing the setting of the drying temperature and / or the drying time of the prepreg production,
This was performed by adjusting the degree of curing of the resin of the stage. The minimum melt viscosity of the resin at the time of heating and pressing the core layer prepreg was 0.03 MPa · s in each case.
The amounts of sodium oxide contained as impurities in the aluminum hydroxide used in each example are as shown in Table 1.

Regarding the composite laminate of each of the above examples,
The cross section was observed. FIG. 1 schematically shows a cross section of the composite laminate of the embodiment. The surface layer resin reaches from the surface layer 1 to the core layer 2 and forms a resin reservoir 3 in the core layer. A large number of resin reservoirs 3 are distributed in the core layer. On the other hand, the composite laminate of Comparative Example 1 was not remarkable even if a resin puddle was formed, and the composite plies of Conventional Examples 1 and 2 did not have a resin puddle.
Table 1 also shows the dimensional maximum value of the formed resin reservoir 3 and the measurement results of the solder heat resistance. In the table, the minimum melt viscosity of the surface layer prepreg resin was measured using an elevated flow tester (heating rate 2).
° C / min). The maximum value of the resin pool size is the maximum size of the resin pool observed within a cross-section observation length of 10 cm of the test piece. The solder heat resistance is obtained by floating a test piece on molten solder (260 ° C.) based on JIS-C5013 and measuring the time until blistering occurs on the test piece surface (n =
5 average).

[0017]

[Table 1]

As is clear from Table 1, in the embodiment according to the present invention, the resin pool is formed well and the solder heat resistance is excellent. Aluminum oxide as an impurity.
Good solder heat resistance is maintained even when the content is more than 1% by mass and 0.16% by mass (Examples 2 to 5). When aluminum hydroxide for high heat resistance is employed, the solder heat resistance is further improved as compared with the conventional example employing the same aluminum hydroxide (comparing Example 1 with Conventional Example 1).

[0019]

As described above, in the composite laminate according to the present invention, although the core layer resin contains aluminum hydroxide as an inorganic filler, the surface layer resin is connected to the surface layer. Since the resin layer extends to the core layer in the state and forms a resin pool distributed in the core layer, the heat resistance is good.
Further, the method according to the present invention is an effective method for producing a composite laminate having the above-described configuration.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a cross section of a composite laminate according to an embodiment of the present invention.

[Explanation of symbols]

 1 is a surface layer 2 is a core layer 3 is a resin pool

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29K 105: 16 B29K 105: 16 309: 08 309: 08 B29L 7:00 B29L 7:00 9:00 9: 00 (72) Inventor Masayuki Noda 2-8-7 Nihonbashi Honcho, Chuo-ku, Tokyo F-term in Shin-Kobe Electric Machinery Co., Ltd. 4F100 AA17B AA19B AB17C AB33C AC10B AG00A AG00B AK53A AK53B BA02 BA03 BA07 BA08 BA10A BA10C BA16 DG11A01B15 DH01B GB43 JJ03 4F204 AA39 AB11 AB16 AD03 AD16 AG01 AG03 FB22 FF01 FF05 FF06 FG09

Claims (3)

[Claims] 1. A surface layer in which an epoxy resin composition is held on a glass fiber woven base material and a core layer in which an epoxy resin composition containing at least aluminum hydroxide as an inorganic filler is held on a glass fiber nonwoven base material. In the composite laminate integrated by heat and pressure molding, the surface layer resin extends to the core layer in a state of being connected to the surface layer,
A composite laminate comprising a resin pool distributed in a core layer. 2. The method according to claim 1, wherein aluminum hydroxide is used as an impurity.
The composite laminate according to claim 1, wherein the composite laminate contains more than 1% by mass of sodium oxide. 3. A glass fiber nonwoven fabric comprising a prepreg obtained by impregnating a glass fiber woven fabric substrate with an epoxy resin composition and drying by heating, the epoxy resin composition comprising at least aluminum hydroxide as an inorganic filler. The prepreg obtained by impregnating the substrate and heating and drying was used as the core layer of the surface layer,
In the production of a composite laminate in which these are integrated by heat and pressure molding, the resin has a minimum melt viscosity of 50 at the time of heat and pressure molding.
Surface layer prepreg adjusted so as to be ~ 500 Pa · s, and the minimum melt viscosity of the resin at the time of the heat and pressure molding is adjusted so as to be higher than the minimum melt viscosity of the surface layer prepreg, and the molten resin can flow in. A method for producing a composite laminate, comprising using a core layer prepreg having a large void.