JPS6169409A - Manufacture of prepreg - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet, the molding properties during the laminate molding of which is good and at the same time which has good surface smoothness and heat resistance, by a method wherein glass base materials are impregnated with resin and once dried and resin is coated respectively on the back side of one glass base material and on the front side of the other base material by the thickness, the sum of which coated on said back side and on said front side exceeds 10mum. CONSTITUTION:Firstly, glass base materials are impregnated with resin and once dried in order to bring the resin in semi-hardened state. Secondly, resin layer is provided by coating resin respectively on the back side of one glass base material and on the front side of the other base material by the thickness, the sum of which coated on said back side and on said front side exceeds 10mum. Consequently, because the resin layer 2, the thickness of which is about 10mum and more or adequate, exists between the base materials 1 and 1, the mutual contact between the base materials 1 and 1 is eliminated, resulting in enhancing the bonding strength between both the base materials 1 and 1 enough high. At the same time, the thickness of a laminated sheet can be increased by the thickness of the resin layer. Further, because the resin layer exists on the surface of prepreg and consequently glass threads are not exposed, the smoothness of the laminated sheet is improved. Furthermore, because the forming is done under the state that the resin layer is interposed between the base materials, no mutual dislocation between the base materials occurs, resulting in improving the molding properties during the laminate molding of the laminated sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing prepreg used for laminates for electronic devices and the like.

[Background technology]

Prepreg is produced by laminating and molding predetermined sheets of prepreg together with copper foil to make a copper-clad laminate, or by laminating and molding prepreg by placing prepreg on both sides of an inner layer printed wiring board and copper foil on the outside. It is used to make stretched laminates.

Prepreg is usually made by impregnating a base material with resin and then drying it so that the resin is semi-hardened. However, if a glass base material such as glass cloth is used as the base material, it can be made in this way. If a laminate is made using prepreg, the heat resistance of the resulting laminate will deteriorate; ■When the number of prepregs to be used is determined, even if the resulting laminate is thinner than the desired thickness, Problems such as the inability to increase the thickness further, (1) poor surface smoothness of the resulting laminate, and (2) poor formability during lamination molding have occurred. For example, in the manufacture of glass epoxy stacked N-slopes, a prepreg made by impregnating a glass cloth with an epoxy resin is used, but the resin content of such prepreg is usually determined from the relationship between the apparent volume and the actual volume of the glass cloth. ,
43% by weight or less (in the case of 7628 type manufactured by Nittobo Co., Ltd., which is a relatively thick and standard type of glass cloth), and glass cloth does not blend well with resin, so it is difficult to use resin any more. It is difficult to increase the content. Therefore, it is not possible to increase the thickness of the laminate by increasing the amount of resin contained in the prepreg, and it is not possible to increase the thickness of the laminate by increasing the amount of resin contained in the prepreg. Even if you try to make a laminate with a thickness of about 1.6 tsuru, you can only make it about 1.5 tsuru thick at most. In addition, since the resin content of the prepreg is low, after lamination molding, as shown in Figure 1, there are areas where the glass cloths 1 and 1 come into contact with each other, reducing the adhesive force between them due to the resin. , peeling between the eyebrows is more likely to occur, heat resistance often deteriorates, and the glass fibers become thicker and the surface becomes softer. - In many cases, moldability deteriorated due to poor lubricity and laminated molding special number ribs shifting from each other. In the figure, 1a is a glass thread [Object of the invention] This invention was made in view of the above circumstances,
Even if the number of resin-impregnated base materials used is the same, the thickness of the laminate can be made thicker than before, and the laminate has good formability during lamination molding, as well as good surface smoothness and heat resistance. The purpose is to provide a method for producing prepreg that can obtain the following.

[Disclosure of the invention]

In order to achieve the above-mentioned objects, the present invention proposes a prepreg manufacturing method in which a glass substrate is impregnated with resin, once dried, and then the resin is applied to the front and back surfaces with a total thickness of 10 μm or more. This is the summary. The present invention will be explained in detail below.

In the prepreg manufacturing method according to the present invention, a glass base material is impregnated with resin, then dried to semi-cure the resin, and then coated with resin to a thickness of 10 μm or more on both front and back surfaces. Try to create layers. The resin layers may have the same thickness on the front and back surfaces, or the resin layers on the front and back surfaces may have different thicknesses. In short, it is sufficient that the total thickness of the front and back surfaces is 10 μm or more. If necessary, the resin layer is semi-cured. The prepreg thus obtained is laminated and molded. Then, in the resulting laminate, as shown in FIG. 2, resin N2 with an appropriate thickness of about 10 μm or more is formed between the base materials 1, 1, so that the base materials 1, 1 do not come into contact with each other. , and the adhesive strength between the two base materials 1 and 1 due to the resin becomes sufficiently high. In the figure, 1a is a glass thread.

At the same time, the thickness of the laminate can be increased by the amount of resin required.Also, since a resin layer is formed on the surface of the prepreg and the glass threads are hidden, the smoothness of the laminate is improved.
Since molding is performed with a resin layer interposed between the base materials, the base materials do not shift from each other, and moldability is also improved. If the thickness of the resin layer between the base materials is less than 10 μm, there will be problems such as insufficient adhesion between the base materials and poor moldability. The thickness of the resin layer on the outer surface of the prepreg used as the outermost layer is preferably 5 μm or more. 5
This is because if the thickness is less than μm, the smoothness of the resulting laminate tends to decrease. For example, when a resin layer with a thickness of 5 μm is provided, the surface roughness of the laminate is reduced to about 2.0 μm, whereas it is 3 to 3.5 μm when there is no resin layer. Another reason is that when a metal foil such as copper foil is placed on the outermost side, the adhesive force between the outermost base material and the metal foil tends to decrease. The proportion of resin in the prepreg is preferably 55% by volume or more.

In the prepreg manufacturing method according to the present invention, a base material made of glass such as glass cloth or glass nonwoven fabric is used.

Besides the glass, some other ingredients may also be added. The type of resin is not particularly limited. For example, epoxy resin, unsaturated polyester resin, polyimide resin, etc. are used.

〔Effect of the invention〕

In the prepreg manufacturing method according to the present invention, a glass substrate is impregnated with resin, once dried, and then the resin is applied to a thickness of 10 μm or more on the front and back surfaces.
Even if the number of resin-impregnated substrates used is the same, the thickness of the laminate can be made thicker than before, and the laminate has good formability during lamination molding, and also has good surface smoothness and heat resistance. can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged vertical cross-sectional view of a laminate made using prepreg obtained by a conventional manufacturing method, and FIG. FIG. Agent: Patent Attorney Takehiko Matsumoto Figure 1 Figure 2

Claims (4)

[Claims] (1) A prepreg manufacturing method in which a glass substrate is impregnated with a resin, once dried, and then the resin is applied to a thickness of 10 μm or more on both front and back surfaces. (2) Claim 1 in which the glass substrate is glass cloth
Prepreg manufacturing method described in section. (3) The method for producing a prepreg according to claim 1 or 2, wherein the resin is an epoxy resin and/or a polyimide resin. (4) The method for producing a prepreg according to any one of claims 1 to 3, wherein the proportion of resin in the prepreg is 55% by volume or more.