JP2006258819A - Test method for press hot platen precision - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test method for a hot platen precision which can be analyzed on a condition adapted to an actual molding. <P>SOLUTION: A prepreg in which a grid like marking 1 and a circular marking 2 capable of discrimination after a heat pressurization are formed on a surface is placed between the press hot platens and is carried out the heat pressurization. Then, a variation of the grid like marking 1 and the circular marking 2 is checked after the heat pressurization, thereafter, a parallelism of the hot platen is checked. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a press hot plate (hereinafter referred to as hot plate) accuracy inspection method.

A printed wiring board material and an electrical laminate for electrical insulation are manufactured by stacking a predetermined number of prepregs and heating and pressing them.
The multilayer printed wiring board is manufactured by stacking components through a prepreg and heating and pressing. Here, the constituent materials are an inner layer material and an outer layer material, 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. .

The 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 making the impregnated thermosetting resin semi-cured.
The thermosetting resin impregnated in the prepreg is once melted by heating to be in a fluid state, and then a curing reaction proceeds to change into an insoluble and infusible cured resin. The fluidity when the thermosetting resin impregnated in the prepreg is melted depends on the composition of the resin and the conditions for making it into a semi-cured state. If this fluidity is not appropriate, it may cause product defects such as voids and scum.
Conventionally, this fluidity has been examined by experimentally heating and pressing a prepreg.

For both electrical laminates and multilayer printed wiring boards, a press equipped with a parallel hot plate (hereinafter simply referred to as a hot plate) is used for molding. Molding by a press equipped with a hot plate is generally called parallel plate molding.
In parallel plate molding, the hot plate accuracy affects the quality of the product. If the accuracy of the hot plate, in particular, the parallelism is not appropriate, pressure unevenness can occur and the thickness accuracy is deteriorated.
Conventionally, as a method for inspecting the accuracy of the hot plate, a solder wire is placed between the hot plates, and after pressurizing or heating and pressurizing, a method of measuring the thickness of the solder wire, a pressure sensitive paper is put between the hot plates, A method of knowing the pressure distribution based on the degree of discoloration of the pressure sensitive paper after pressurization is known.

The fluidity of the prepreg cannot be examined by a method using a solder wire or a method using pressure sensitive paper. Also, in actual molding, the presence of cushions, circuit irregularities, and jigs also influences, so the conditions are not the same as those for molding.
The hot plate accuracy cannot be inspected simply by a method in which the prepreg is heated and pressed experimentally by a press.
It is an object of the present invention to provide a hot plate accuracy inspection method that can be analyzed under conditions suitable for actual molding.

The present invention is characterized in that a prepreg formed with a marking identifiable on the surface after heating and pressing is placed between the heating plates and heated and pressed to check the parallelism of the heating plate from the change of the marking. This is an accuracy inspection method.
The marking changes as the resin of the prepreg flows due to heating and pressurization. The fluidity can be determined from the degree of change of the marking, particularly the moving distance.
And if the change of marking by the resin of a prepreg flowing is equal, it can be judged that the parallelism of a hot plate is good. Note that quantitative confirmation of the hot plate accuracy is possible by measuring the thickness of the prepreg after heating and pressing.

  According to the present invention, the hot plate accuracy can be inspected by the same operation as that for examining the fluidity of the resin of the prepreg.

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 most suitable. Water-based inks are not preferred because they have poor affinity with thermosetting resins and cannot be marked. Also, markings such as engravings are not suitable because they disappear during heating and pressing.
The color tone of the ink may be a color tone different from that of the thermosetting resin, and there is no other limitation.

  The marking is preferably symmetrical on the entire surface of the prepreg. As such a marking, for example, a lattice-shaped marking 1 as shown in FIG. Further, instead of using a single shape, for example, as shown in FIG. 1 (a), markings of several shapes are used together so as to draw a circular marking 2 in the lattice of the lattice-like marking 1. Is preferred.

Using an oil-based felt pen on a glass cloth base epoxy resin prepreg (made by Hitachi Chemical Co., Ltd., GEA-67N (trade name)) having a thickness of 0.2 mm and 510 × 510 mm, a straight line having a width of 3 mm is formed. The grid-like markings 1 were formed by being drawn vertically and horizontally at intervals of 50 mm, and further, circular marks 2 were formed by drawing a medium-black circle having a diameter of about 5 mm at the center of each grid (see FIG. 1A).
One prepreg was inserted between stainless steel mirror plates, and heated and pressurized at a temperature of 170 ° C. and a pressure of 3 MPa for 120 minutes. As a result, the marking changed as shown in FIG. It is confirmed that the flow direction and degree of flow of the resin can be clearly understood, and that the parallelism of the hot plate is also good in view of the form of the grid-like marking 1b after heating and pressing and the circular marking 2b after heating and pressing. It was.

  Using a press in which the central portion of the hot plate was recessed due to wear, heating and pressurization were performed in the same manner as in Example 1. 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 and the hot press after heating and pressing. It was in the form of a later circular marking 2c. Therefore, the hot plate was ground to correct the parallelism and heated and pressurized in the same manner as in Example 1. As a result, the marking of the prepreg was almost the same as in FIG. 1B, and it was confirmed that the parallelism of the hot plate was equivalent to the press of Example 1.

  Heating and pressing were performed in the same manner as in Example 1 using a press having a disordered hot plate parallelism. As a result, the marking was as shown in FIG. That is, since the resin flows toward a portion where the hot plate interval is wide, the lines of the circular marking 2 and the lattice-shaped marking 1 are also in a form like the lattice-shaped marking 1d after heating and pressing and the circular marking 2d after heating and pressing. It was. In addition, FIG.1 (d) extracts and shows the part with large disorder of marking. From FIG.1 (d), it was judged that the space | interval of a hot plate space | interval became large the part of the prepreg corresponding to FIG.1 (d). Therefore, a spacer was inserted between the hot plate and the press main body to adjust the parallelism, and heating and pressing were performed in the same manner as in Example 1. As a result, the marking of the prepreg was almost the same as that in FIG. 1B, and it was confirmed that the parallelism of the hot plate was equivalent to that of the press of Example 1.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view regarding one Example of this invention, (a) shows the state before heat pressurization, (b) shows the state after heat pressurization, (c) and (d) are also heat pressurization similarly. The part with a large disturbance in the later state is extracted and shown.

Explanation of symbols

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

Claims (1)

  Press hot plate accuracy, characterized by placing a prepreg with markings that can be identified on the surface after heating and pressing between the hot plate and heating and pressing to check the parallelism of the hot plate from the change in marking Inspection method.

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