JPH0114025B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a synthetic resin laminate used as an insulating board or the like with high accuracy in board thickness. Synthetic resin laminates are made by impregnating a continuous sheet-like fibrous base material such as paper or cloth with a synthetic resin varnish such as phenolic resin or epoxy resin and drying it to a B state. Prepreg is cut into a predetermined length and a predetermined number of sheets. It is manufactured by stacking them together and applying heat and pressure. Since the sheets of paper, cloth, etc. used at this time are made of continuous material, the prepreg is also used by cutting continuous material. When manufacturing a laminate, for convenience of work, it is customary to stack the prepregs in the order in which they are cut and heat and press them. In this case, the paper or cloth has irregularities in papermaking and weaving during manufacturing, but these irregularities also tend to be continuous, so when stacking several sheets, these irregularities are It appears amplified on the board. The present invention has been made in view of these points, and involves cutting a prepreg into a predetermined length into a predetermined length by impregnating a continuous sheet-like base material with synthetic resin varnish and drying it, and then stacking a predetermined number of sheets and heating them. In the method of manufacturing a pressed synthetic resin laminate, at least half of the pre-preg sheets cut to a predetermined length are cut in the order in which they were cut, that is, the continuous sheet-like base material becomes discontinuous. It is characterized by being stacked. For example, by using different lots of paper or cloth base materials for the prepregs stacked on top of each other, or by cutting a continuous sheet of prepreg to a predetermined length and changing the orientation of the cut prepregs, The unevenness cancels out each other, resulting in a laminate with uniformity. As for the condition that the original paper or cloth is not continuous, it is necessary that at least 50% of the sheets of the same paper or cloth cut as prepreg are laminated in random order, and it is desirable that the sheets of paper or cloth are stacked in random order. It's good that the lotto changes. Example Bleached kraft paper impregnated with phenolic resin (weighed
140g/m ² ) prepreg (resin amount 100g/m ² ) was continuously cut to 1050mm x 1050mm, 8 sheets were stacked in succession, and heated at 170℃ for 60 minutes and at a pressure of 80℃ using the usual method.
A laminate was manufactured by lamination molding under the condition of Kg/cm ² . Let this be A. Next, eight sheets of prepreg manufactured by impregnating phenolic resin using bleached kraft paper (weighing 140 g/m ² ) with different raw rolls were selected, each with a different raw roll, and stacked in a conventional manner. by
A laminate plate was produced by lamination molding at 170°C for 60 minutes and at a pressure of 80 kg/cm ² . Let this be B. The thickness of the 30 laminates A and B was measured and the results are shown in the table below. As can be seen from this result, laminate B had little variation in plate thickness and was good.

[Table] As explained above, sheet-like materials (paper, cloth, and prepregs made from these materials) that are generally manufactured continuously into sheets tend to have a density distribution in the flow direction. This tendency is further amplified in stacked laminates, but since discontinuous raw material is used in the present invention, these density distribution trends cancel each other out, resulting in a uniform product. It has the effect of reducing not only thickness variations but also warping, twisting, and scratching. In addition, since the variation in plate thickness can be reduced, it is possible to
The plate thickness of 1.6±0.2mm was changed to 1.5mm by this invention.
It also has the effect of saving material costs by ±0.1mm.

Claims (1)

[Claims] 1. A method for producing a synthetic resin laminate, in which a continuous sheet-like base material is impregnated with a synthetic resin varnish, dried and prepreg brought to a B state is cut into predetermined lengths, and a predetermined number of sheets are stacked and heated and pressed. A method for producing a synthetic resin laminate, comprising stacking at least half of the predetermined number of prepregs cut to a predetermined length without following the order in which they were cut. 2. The method for producing a synthetic resin laminate according to claim 1, characterized in that prepregs cut to a predetermined length are stacked so that adjacent prepregs have different raw rolls.