Last time, we explained the common quality problems and solutions of epoxy laminates. Because of the more common quality problems in the epoxy laminates, we continue to share the problems and solutions to them today.
1. The sticky steel plate or the surface of the oil flower. It is mainly caused by the improper use of deglutinant or the most inappropriate punishment. Different adhesives used by different adhesives are different, such as the phenolic resin type can be used oleic acid, and the epoxy phenolic resin must use zinc stearate (in l%~1.5%), and the external deoxidizing agent is useful for Black wax or silicon cool. In addition, the steel plate is too poor to be repolished before being used. The release agent should be properly concentrated and coated evenly, otherwise the steel plate will be easily adhered or the oil flowers will be produced.
2. Run the material when it is pressed. When the glass cloth is often produced, the resin has not formed a cementitious elastomer at the preheating stage. The resin content is the most and the soluble resin content is large, and the preheating period is insufficient and the pressure is too fast. Therefore, qualified pre impregnated materials should be selected, and then the pressure should be boosted according to the flow state of the glue. In addition, when the hot plate is not parallel, it can also cause uneven blank pressure and lead to run-off, so it should be timely gun investigation and adjust the parallelism of the hot plate.
3. The thickness deviation of the laminates is large. Thick plate deviations usually are thick on one side and thin on the other side or thick in the edge. This is mainly caused by the size of the pre impregnated material on one side and the other side of the rubber. In addition, the edge of the steel plate is caused by the edge and uneven edge. In addition, the inclined plate of the press can also cause the thin side and thin side. Therefore, attention should be paid to maintaining the steel plate and placing materials, dressing the edges of the boards in time, and noting the aging materials and folding materials.
4. The dielectric properties of the epoxy laminates are not qualified. The unqualified tangent values of voltage resistance and dielectric loss angle are mainly caused by the high volatile content of preprepreg and the failure to take corresponding measures during damp pressing. The remedy is often to heat the laminate after heat treatment at 120 or 140 degrees Celsius, and vacuum drying is better. The dielectric properties of some products often take into account whether the selection of the adhesive formula is appropriate and the pressing process is reasonable. The dielectric properties of the general pure epoxy resin are better than that of the epoxy phenolic resin.
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