JPS62279906A - Meathod of measuring dryness of prepreg for laminated sheet - Google Patents

Abstract

PURPOSE:To measure a volatile quantity swiftly and correctly, by observing a degree of coloration of a thing to be obtained by applying a solution of ferric oxide to a prepreg after drying of priming as a dryness measuring means posterior to the priming. CONSTITUTION:Craft paper of 0.1mm in thickness is impregnate with primer varnish to be obtained by diluting precondensated resin of phenolic formalin with methanol and water (a mixture weight ratio is methanol: water=7:3) and dried so that an adhesive quantity of resin becomes 10 wt%. On the other hand, preparations for a coloration reagent are performed by compounding a solution of ferric oxide so that concentration becomes 35 wt% and by filling said solution into a vessel of hand spray. Drying is performed so as to preset priming dryness at voltaile amount of 3.5% and remaining unreacted phenolic amount of 15% (they are wt%). In this instance, coloration is given in purplish blue so that brightness based on a color difference meter is 50%, in color reaction of phenolic ferric oxide. Control of drying is performed so that the dryness becomes a preset value while a degree of coloration is confirmed by performing continuous production for 24 hours and spraying the reagent to said pregreg, which is under continuous production, every hour.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to a method for measuring the dryness of prepregs used when manufacturing laminates used in electronic devices and the like.

BACKGROUND TECHNOLOGY Conventionally, a method for producing prepreg for laminates and a two-stage coating method using a fat varnish and, most importantly, a phenol-based or epoxy-based varnish, have been known. In this two-stage coating for manufacturing prepreg for laminates, as a method to check the degree of dryness after undercoating, the prepreg after undercoating is heat treated for 110 minutes at 160" C, for example, and the amount of volatile matter is measured. has been more commonly practiced than before.

Problems to be Solved by the Invention Confirming the dryness of the undercoat using the above method has the following problems.

[11 When carrying the prepreg after drying the undercoat to an oven for measuring volatile content (hereinafter referred to as "oven"), or when taking out the prepreg from the oven and measuring the volatile content by the difference in weight before and after heat treatment, the atmosphere The prepreg absorbs moisture due to the moisture inside, making it difficult to determine the true volatile content and causing errors in dryness measurements.

(2) After the undercoat has dried, the prepreg must be separately heat-treated and collected by cutting out colored pieces. This may cause the prepreg to break during continuous production and cause interruptions in coating production.

(3) In order to measure the amount of volatile matter, the prepreg is usually heat treated in an oven for about 10 minutes, but it takes more than 10 minutes after the prepreg for measurement is collected until the amount of volatile matter can be confirmed.

The present invention solves the above problems and quickly reduces the amount of volatile matter.
The purpose of the present invention is to provide a prepreg dryness measurement method that can accurately measure the degree of dryness of prepregs and can contribute to efficient production of prepregs with stable quality.

Means for Solving the Problems In order to achieve the above object, the present invention provides a method for producing prepreg for laminates using a phenolic resin varnish as an undercoat, by applying a ferric chloride solution to the prepreg after the undercoat has dried. The degree of dryness after undercoating is measured based on the degree of coloration of the perilla.

How to check the dryness of the prepreg after drying the undercoat:
We have conventionally measured the amount of volatile matter in the prepreg, and as a result of investigating factors related to the amount of volatile matter, we found a correlation between the residual unreacted phenol content in the prepreg and the volatile content. This is shown in Figure 1'''.Here, based on the conventional knowledge that phenol exhibits a unique coloring reaction with ferric chloride, and as a result of further investigation, we found that It has been found that by adhering and impregnating a ferric chloride solution of a certain concentration, the prepreg exhibits a coloration depending on the amount of residual unreacted phenol.This result shows that the amount of residual unreacted phenol in the undercoat prepreg can be reduced. It is now possible to easily quantify the amount of volatile matter related to the phenol content, and the amount of volatile matter related to the phenol content can be immediately measured with less error than the conventional method of measuring volatile matter using the oven method.

The degree of coloring caused by this ferric chloride is shown in FIG. It is sufficient to check the color reaction with the naked eye, but in order to control the numerical values, it is preferable to check with an instrument as shown by the brightness box in Figure 2. If a colorimeter or color difference meter is used, Accuracy is further improved.

Due to the above-mentioned features, the present invention allows the volatile content and undercoat dryness to be more accurately determined by coloration, thereby solving the conventional problems, specifically, when collecting and weighing prepreg for volatile content measurement. This solves the problem of errors caused by moisture absorption, as well as the trouble and time required to measure volatile content. Furthermore, it is possible to directly impregnate and impregnate prepreg with ferric chloride solution during continuous production and color it, which eliminates the problem of interruptions in coating production due to cuts in the prepreg that conventionally occur when collecting prepreg for measurement. It is something that will be resolved.

According to the present invention, the punching workability of the laminate, dimensional changes, warpage,
The undercoat dryness, which affects properties such as color tone, can be checked accurately and effectively in a simple manner, and the quality of the laminate plate is stable. Examples of the present invention and conventional examples are shown below. explain.

Example 1 Phenol-formalin initial condensation resin was mixed with methanol and water (the mixing weight ratio was methanol:water = 7:3) so that the resin adhesion amount was more than 10% by weight on kraft paper with a thickness of O.Lm.
) and dried. On the other hand, a ferric chloride aqueous solution was prepared to have a concentration of 35% by weight, and the solution was packed in a hand spray container to prepare a coloring reagent.

Whether drying is performed to set the undercoat dryness to 3.54 volatile content and 15 alr residual unreacted phenol content (each based on weight), as is clear from the correlation shown in Figures 1 and 2. In the phenol-ferric chloride color reaction, a blue-purple color with a brightness of 50% measured by a colorimeter (manufactured by Nippon Seishoku ■) is produced. Continuous production was carried out for 24 hours, and a reagent was sprayed every hour on the prepreg during continuous production, and drying was adjusted accordingly.

The undercoat and topcoat are applied sequentially, but after the undercoat dries,
A prepreg for a laminate was obtained by overcoating with tung oil-modified phenolic resin varnish and drying.

The 8 sheets of prepreg and the thickness 35/A placed on the surface
A single-sided copper-clad laminate having a thickness of 1.6 mm was manufactured by laminating and molding the RRL copper foil.

Example 2 Using kraft paper with a thickness of 0.1 m, the same undercoating varnish as in Example 1, and a coloring reagent which is an aqueous ferric chloride solution,
The undercoat was dried so that the volatile content and other prepreg properties were the same as in Example 1, but hourly confirmation using a coloring reagent was carried out to ensure that the LOcr from the undercoat prepreg during continuous production was
The prepreg for measurement which was cut out and collected was directly immersed in a reagent placed in a beaker.

A single-sided copper-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Example 1.

An undercoat was dried using the same kraft paper and undercoat varnish as in the conventional example. The dryness of the undercoat was similarly set at 3.5% volatile content and 15% residual unreacted phenol content. Undercoat drying The prepreg cut into l Ocm holes from the prepreg during continuous production was treated in an open setting at 160"C for 10 minutes, and the dryness reached the set value while measuring and checking the volatile content every hour. A single-sided copper-clad laminate having a thickness of 1.6 mm was obtained in the same manner as in Example 1.

Table 1 shows the results of the coatings performed in Example 1.2 and the conventional example and the variation in properties of the laminates.

In the above embodiments, water was used as the solvent for the molten ferric chloride at °C1, but any solvent such as acetone, methanol, etc. that dissolves ferric chloride may be used.

) VT Royal Note (1) Total time per measurement (2) Re-checked with residual unreacted phenol content, and the difference between the maximum and minimum phenol weight range (2)
Measured 4 times: n=24) (When undercoat dryness is checked 24 times for 3124 hours) (4) and (5) This is a guideline for the variation in Examples, where the conventional variation level is 100.

Effects of the Invention As described above, the present invention provides the following advantages in the production of prepreg by two-stage coating using phenolic resin varnish as the undercoat.
By using a very simple method of checking the degree of dryness of the undercoat, which has an important meaning in the properties of the laminate, by the degree of coloration of the ferric chloride solution, it is possible to dry the undercoat accurately, efficiently, and economically. The industrial value of this method is extremely great in that it is possible to manufacture prepregs for laminates and laminates with stable quality.

[Brief explanation of the drawing]

Figure 1 is a curve diagram showing the relationship between the amount of volatile matter contained in the prepreg after drying the undercoat and the amount of residual unreacted phenol, and Figure 2 is the amount of residual unreacted phenol in the prepreg after drying the undercoat. FIG. 3 is a curve diagram showing the relationship between the degree of coloring caused by ferric chloride group ζ and ferric chloride group ζ.

Claims (1)

[Claims] In the production of prepreg for laminates, in which varnish is applied in two stages, an undercoat and a topcoat, and a phenolic resin varnish is used as the undercoat, a ferric chloride solution is applied to the prepreg after the undercoat has dried as a means of measuring the dryness after the undercoat. A method for measuring the dryness of prepreg for laminates, which is characterized by coating and observing the degree of color development.