JPH06143017A - Back-up board for drilling - Google Patents

Abstract

PURPOSE:To easily judge the state of penetration of a drilled hole by means of a pit hole at a clear contrast between the color phase of the end part of the opening of the pit hole and the color layer of the inside of the pit hole by providing one prepreg on the surface and the other prepreg on the inside to superimpose them on one another, and by heating and pressurizing the entire body for integrated lamination. CONSTITUTION:A prepreg A, for which a reaction mixture between mononuclear or multinuclear hydroxymethylphenol, which is provided by inducing reaction between a trifunctional phenol group and aldehyde under an alkaline catalyst, and normal salt, for which the alkaline catalyst is neutralized by acid, is impregnated and dried on a mixed paper base material mixed with white pigment, and a prepreg B, for which mononuclear or multinuclear hydroxymethylphenol containing alkaline catalyst, which is formed by inducing reaction between a trifunctional phenol group and aldehyde under an alkaline catalyst, is impregnated and dried on a paper base material, are provided. The prepreg A is provided on both surfaces, while the prepreg B is provided on the inside, and they are superimposed on one another. The entire body is heated and pressurized, to form a multilayered structure in an integrated form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called backup board which is used as a lining for drilling.

[0002]

2. Description of the Related Art A backup board is used as a backing on the underside of a drilled product in order to improve the finish of the drilled hole during drilling.
This backup board improves the finished dimensional accuracy of the drill holes and improves the hole characteristics when drilling a large number of small-diameter holes such as component mounting holes of printed wiring boards and pilot holes for through-hole plating with a drill blade. Those that do not have an adverse effect are required. As a conventional backup board, a paper-based phenolic resin laminate (conventional example 1) or a multilayered laminate having a paper-based melamine resin surface and a paper-based phenolic resin inside (conventional example 2) is mainly used. .
The conventional example 1 improves the finished size of the drilled hole and does not adversely affect the hole characteristics, but recently, as a method of simply knowing the penetration state of the drilled hole of the processed hole, the drill edge is It may be judged by observing the processing state of the pit hole that penetrates into the backup board and is drilled. There is a problem that it is difficult to see when observing the processed state of such a pit hole. Further, in the conventional example 2, since the hue of the surface and the hue of the inner phase portion are different, the processing state of the pit hole, that is, the hue of the opening edge portion and the hue of the inner phase portion exposed inside the pit hole are different. Although it can be clearly observed, the difference in the resin state between the surface part and the interior causes a difference in the cured state, which tends to cause warping and twisting, and the surface melamine resin layer has a high hardness. There is also a problem that the chip of the drill blade becomes large.

[0003]

In order to solve the above-mentioned problems, the backup board for drilling of the present invention comprises a mixed paper base material containing a white pigment and a trifunctional phenol and aldehyde. A prepreg A impregnated with a reaction mixture of mononuclear or polynuclear hydroxymethylphenol obtained by reacting under an alkaline catalyst and a normal salt obtained by neutralizing the alkaline catalyst with an acid, and a paper substrate,
A prepreg B is prepared by impregnating mononuclear or polynuclear hydroxymethylphenol containing an alkaline catalyst obtained by reacting a trifunctional phenol with an aldehyde under an alkaline catalyst and drying the prepreg A on both sides. Was placed inside and superposed, and the whole was heated and pressed to form a multilayer structure in which they were integrally laminated.
The white pigment is not particularly limited, but zinc white (Zn
O), lead white (2PbCO ₃ · Pb (OH) ₂ ), basic sulfate (nPbSO ₃ · PbO), lead sulfate (PbS)
O ₄ ), trypone (ZnS + BaSO ₄ ), zinc sulfide (ZnS), titanium oxide (TiO ₂ ), antimony oxide (Sb ₂ O ₃ ), and the like, and the mixing ratio is 5
The range of 0% to 5% is preferable. The pulp used for the paper base is not particularly limited, but the one used for the mixed paper base may be any one capable of mixing white pigments, and preferably bleached pulp is used. It will not damage the color. Examples of the trifunctional phenols include phenol, cresol, xylenol, and resorcin trifunctional monomers, and any of them may be used. Examples of the aldehyde include formaldehyde, acetaldehyde, and furfural, and any of them may be used. The alkaline catalyst is not particularly limited as long as it can be used as a catalyst for an alkaline hydroxymethylation reaction, and amines, alkali metal hydroxides and the like can be used. As the amine, an amine having an amino group, an imino group or a nitrilo group can be used. As the alkali metal hydroxide, sodium hydroxide, lithium hydroxide or potassium hydroxide can be used. The acid for neutralizing the alkali catalyst is not particularly limited, but phosphoric acid or the like can be used. Since the prepreg A neutralizes the alkali catalyst with an acid to form a normal salt, the ionic content of the prepreg A is reduced as much as possible. Since the number of chromophores having a saturated bond is small and the refractive index of light is small, the phenol resin component of prepreg A exhibits a light colored transparency, and the white pigment inside can be seen through from the outside. Since prepreg B contains an alkaline catalyst inside and contains negative ions, a chromophore having an unsaturated bond is generated in the molecule of the cured product when cured by heating under pressure, and the resin species and catalyst type It becomes opaque with a unique color. In this way, the surface part is transparent through the colored resin that is lighter than the outside, and the white color of the white pigment inside the surface layer can be seen through, and the inside layer is a colored opaque phase, so the pit hole opening edge The state of the part can be clearly observed by the color contrast.

[0004]

Example 1 First, a prepreg A is prepared as follows. Prepare varnish A for prepreg A. As this varnish A, 680 kg of trifunctional phenol, 20 kg of p-nonylphenol, and 627 kg of formalin are mixed with 2.04 kg of sodium hydroxide as an alkaline catalyst and reacted at 100 ° C. to obtain hydroxymethylphenol. At the end of the reaction, 10 kg of phosphoric acid was added to neutralize sodium hydroxide as an alkaline catalyst to precipitate sodium phosphate [Na ₃ (PO ₄ )]. This varnish A has good coatability. For this purpose, 410 kg of MeOH and 16 kg of water are mixed to adjust the viscosity.
In addition, a white pigment-mixed paper base material is prepared. As the mixed paper base material, kraft pulp with titanium white (TiO ₂ ) 1
Titanium white paper mixed with 5% is used. This titanium-white mixed paper was impregnated with a viscosity-controlled varnish A so that the resin content was about 35%, and this was dried to remove MeOH and water to obtain prepreg A. Next, the prepreg B is created as follows. Prepare varnish B for prepreg B. As this varnish B, trifunctional phenol 68
0 kg and 627 kg of formalin are mixed with 2.04 kg of sodium hydroxide as an alkaline catalyst and reacted at 100 ° C. to obtain hydroxymethylphenol, but a material which does not remove sodium hydroxide as an alkaline catalyst from this reaction mixture is used. To improve the coatability of this varnish B, 410 kg of MeOH and 16 kg of water are mixed and the viscosity is adjusted before use. Also, kraft paper is prepared as a paper base material. Varnish B with viscosity adjusted to this kraft paper
Was impregnated so that the resin content was about 35%, and this was dried to remove MeOH and water, and prepreg B was obtained. The resin of the above prepreg A and prepreg B contains p-nonylphenol in addition to the trifunctional phenol for the purpose of imparting flexibility. Next, the prepreg A and the prepreg B are arranged in the order of the prepreg A, the prepreg B, and the prepreg A, and are overlapped with each other, and the whole is heated and pressed to cause a curing reaction of the resin component of the prepreg A and the resin component of the prepreg B. By laminating them integrally, a backup board for drilling was obtained. This backup board for drilling has a multi-layer structure in which the cross section has a multi-layered structure that looks white through the transparent resin of light color on both sides and the inside looks reddish brown.

[0005]

[Comparative Example] A proper number of prepregs B used in Example 1 were stacked, and the whole was heated and pressed to cure the resin component of the prepregs B and to integrally laminate them to obtain a backup board for drilling. . This backup board for drilling had a reddish brown laminated plate with a uniform cross section. The backup boards for drilling in the above-mentioned Examples and Comparative Examples both showed less warpage and twisting after lamination molding, and the straightness of the drill blade during drilling was good, but the processed opening end of the pit hole was good. Regarding the difficulty of observing the edge portion, the color contrast of the example was clearer than that of the comparative example, and it was possible to observe accurately.

[0005]

EFFECTS OF THE INVENTION The backup board for drilling according to the present invention does not damage warpage or twisting, and does not impair the straight movement of the drill blade during drilling. There is an effect that it can be easily judged by the clear contrast between the hue of the edge of the pit hole opening and the color layer inside the pit hole.

Claims (1)

[Claims] 1. A mononuclear or polynuclear hydroxymethylphenol obtained by reacting a trifunctional phenol and an aldehyde under an alkaline catalyst on a mixed paper substrate mixed with a white pigment and the alkaline catalyst with an acid. Dried prepreg A impregnated with the reaction mixture with hydrated normal salt,
The prepreg B obtained by impregnating a paper base material with mononuclear or polynuclear hydroxymethylphenol containing an alkaline catalyst obtained by reacting a trifunctional phenol with an aldehyde under an alkaline catalyst and drying the prepreg A Is placed on the surface, the prepreg B is placed on the inside, and the prepregs B are superposed on each other, and the whole is heat-pressed to be integrally laminated, and a backup board for drilling.