JPH10142138A - Method for panalyzing resin fluidity of prepreg and method for inspecting pressed heat plate accuracy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately examine the fluidity of prepreg resin by forming a marking that can be identified after heated press on a surface, heating and pressing a prepreg by a press, and analyzing resin fluidity from the change in the marking. SOLUTION: A lattice-shaped marking 1 is formed horizontally and vertically with a specific gap using an oil-based felt pen, and further a centered dot circle with a specific diameter is drawn at the center of each lattice, thus forming a circular marking 2. The prepreg is sandwiched between stainless mirror plates and is heated and pressed at specific temperature and pressure for a specific amount of time, thus clearly grasping the degree and direction of flow of resin from the change in the marking and confirming the degree of parallelization of the heated plate from the condition of a lattice-shaped marking 1b and a circular marking 2b after heated press.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for analyzing resin fluidity of a prepreg and a method for inspecting the accuracy of a hot plate (hereinafter referred to as a hot plate).

[0002]

2. Description of the Related Art A substrate material for a printed wiring board and an electrical laminate for electrical insulation are manufactured by laminating a predetermined number of prepregs and heating and pressing them. The multilayer printed wiring board is manufactured by laminating constituent materials via a prepreg and heating and pressing. Here, the constituent materials are an inner layer material and an outer layer material, wherein the inner layer material is a printed wiring board on which an inner layer circuit is formed, and the outer layer material is a single-sided copper-clad laminate or copper foil for forming an outer layer circuit. .

[0003] A prepreg used in the production of a laminated board and a multilayer printed wiring board is obtained by impregnating a thermosetting resin varnish into a fiber base material, and then impregnating the impregnated thermosetting resin into a semi-cured state. The thermosetting resin impregnated in the prepreg is temporarily melted by heating to be in a fluid state, and then the curing reaction proceeds to change into an insoluble and infused cured resin.
The fluidity of the thermosetting resin impregnated in the prepreg when it melts depends on the composition of the resin and the conditions under which the prepreg is brought into a semi-cured state. If the fluidity is not appropriate, it may cause product defects such as voids and blurring. Conventionally, the fluidity has been examined by heating and pressing the prepreg on a trial basis.

A press equipped with a parallel hot plate (hereinafter simply referred to as a hot plate) is used for molding, both for an electric laminate and a multilayer printed wiring board. Forming by a press having a hot plate is generally called parallel plate forming. In parallel plate molding, hot plate accuracy affects product quality. If the accuracy of the hot plate, particularly the degree of parallelism, is not appropriate, pressure unevenness occurs and the thickness accuracy deteriorates. Conventionally, as a method of inspecting the accuracy of the hot plate, placing a solder wire between the hot plate, pressurized, or, after heating and pressurizing, a method of measuring the thickness of the solder wire,
A method is known in which pressure-sensitive paper is placed between hot plates, and after pressure is applied, the pressure distribution is determined based on the degree of discoloration of the pressure-sensitive paper.

[0005]

In a method using a solder wire or a method using pressure-sensitive paper, the fluidity of a prepreg cannot be examined. Further, at the time of actual molding, the same conditions as molding are not obtained because the presence of cushions, unevenness of the circuit, and the presence of jigs also affect the molding. The method of simply heating and pressurizing the prepreg on a test basis with a press cannot check the accuracy of the hot plate. An object of the present invention is to provide a method for analyzing resin fluidity of a prepreg and a method for inspecting the accuracy of a hot plate, which can be analyzed under conditions suitable for actual molding.

[0006]

A first aspect of the present invention is to heat and press a prepreg having a surface on which a identifiable marking is formed after heating and pressurizing by a press, and to analyze the resin fluidity from a change in the marking. A method for analyzing resin fluidity of a prepreg. As the resin of the prepreg flows due to heating and pressing, the marking changes,
The fluidity can be determined from the degree of change of the marking, particularly from the moving distance. The second aspect of the present invention is characterized in that a prepreg having a surface on which a identifiable marking is formed after heating and pressing is placed between hot plates, heated and pressed, and the parallelism of the hot plate is confirmed from a change in the marking. This is a method for inspecting the accuracy of a hot plate. If the change in marking caused by the flow of the resin of the prepreg is uniform, it can be determined that the parallelism of the hot plate is good. The accuracy of the hot plate can be quantitatively confirmed by measuring the thickness of the prepreg after heating and pressing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A marking that can be identified after heating and pressing is a marking that does not disappear by heating and pressing.
As such a marking, a writing instrument using oil-based ink, particularly a felt pen, is optimal. Aqueous inks are not preferred because they have poor affinity for thermosetting resins and cannot be marked. Markings such as stamps are not suitable because they disappear during heating and pressing. The color tone of the ink may be different from that of the thermosetting resin,
There are no other restrictions.

The marking is preferably symmetrical over the entire surface of the prepreg. As such a marking, for example, a grid-like marking 1 as shown in FIG. Also, instead of using a single shape, for example, as shown in FIG. 1A, several shapes of markings are used in combination such that a circular marking 2 is drawn in a grid of a grid-like marking 1. Is preferred.

[0009]

【Example】

Example 1 Glass cloth-based epoxy resin prepreg 0.2 mm thick, 510 × 510 mm (GE manufactured by Hitachi Chemical Co., Ltd.
A-67N (trade name) was drawn using an oil-based felt pen to draw a straight line having a width of 3 mm vertically and horizontally at intervals of 50 mm to form a grid-like marking 1. Draw a 5mm black circle and make a circular marking 2
Was formed (see FIG. 1A). One sheet of this prepreg is inserted between stainless steel head plates, at a temperature of 170 ° C. and a pressure of 3MP.
a and heating and pressurizing for 120 minutes. As a result, the marking changed as shown in FIG. The flow direction and the degree of flow of the resin can be clearly grasped, and the grid-like marking 1b after heating and pressing and the circular marking 2 after heating and pressing
It was confirmed from the view b that the parallelism of the hot plate was also good.

Example 2 Heat and pressure were applied in the same manner as in Example 1 using a press in which the center of the hot plate was concave due to wear. As a result, the marking at the center changed as shown in FIG. That is, since the resin flows toward the concave portion of the hot plate, the lines of the circular marking 2 and the grid-like marking 1 also move toward the concave portion of the hot plate, and the grid-like marking 1c after heating and pressurizing and the heating and pressurizing. This was in the form of the later circular marking 2c. Then, the hot plate was ground to correct the parallelism, and heated and pressed in the same manner as in Example 1. As a result, the marking of the prepreg was almost the same as that of FIG. 1B, and it was confirmed that the parallelism of the hot plate was equivalent to that of the press of Example 1.

Example 3 A hot press was performed in the same manner as in Example 1 using a press having a disturbed parallelism of the hot plate. As a result, the marking was as shown in FIG. In other words, since the resin flows toward the portion where the interval between the hot plates is wide, the lines of the circular marking 2 and the grid-like marking 1 also have a form like the grid-like marking 1d after the heating and pressing and the circular marking 2d after the heating and pressing. Had become. FIG. 1D shows a portion where the marking is largely disturbed. FIG.
From (d), it was determined that the space between the hot plates was large in the portion of the prepreg corresponding to FIG. 1 (d). Therefore, a spacer was inserted between the hot plate and the press body to adjust the parallelism, and heating and pressing were performed in the same manner as in Example 1. As a result, it was confirmed that the marking of the prepreg was substantially equal to that of FIG. 1B, and that the parallelism of the hot plate was equivalent to that of the press of Example 1.

[0012]

According to the present invention, the fluidity of the resin of the prepreg can be accurately investigated. In addition, the accuracy of the hot plate can be inspected by the same operation.

[Brief description of the drawings]

FIG. 1 is a plan view of an embodiment of the present invention,
(A) shows a state before heating and pressurizing, (b) shows a state after heating and pressurizing, and (c) and (d) similarly show a portion after the heating and pressurizing where a large turbulence is extracted. .

[Explanation of symbols]

 1 Lattice marking 2 Circular marking 1b, 1c, 1d Lattice marking after heating and pressing 2b, 2c, 2d Circular marking after heating and pressing

Claims (2)

[Claims] 1. A method for analyzing resin fluidity of a prepreg, comprising: applying a heat and a pressure to a prepreg having a surface on which a identifiable marking is formed after heating and pressing by a press; and analyzing the resin fluidity from a change in the marking. . 2. The method according to claim 1, further comprising placing a prepreg on the surface of which a identifiable marking is formed after heating and pressurizing, placing the prepreg between press hotplates, heating and pressurizing, and confirming the parallelism of the press hotplate from a change in the marking. Press hot plate accuracy inspection method.