Curing process of epoxy laminates
The production process of epoxy laminates has always attracted much attention. Curing molding is also one of the important production processes. For epoxy laminates, it is usually pressed and solidified to be divided into three stages, namely preheating, hot pressing and cooling. Special epoxy laminates must also be heat treated after hot pressing, that is, supplemental curing. Let me introduce the steps of curing the epoxy laminates.
(1) the preheating stage. The blanks are packed into the hot plate of the press, and the hot plate is closed, then the pressure 1-3MPa is given to 100-120, and the 25-45min is kept so that the resin in the pre impregnated material is further penetrated into the blank of the glass fabric fiber, and the volatiles can be further spilled. If the preheating temperature is too high, it is easy to flow glue or even run material (billet slip out of hot plate) and lead to the surface of the laminates. If the preheating temperature is low and the time is insufficient, the 31 overpressure is too fast in the hot pressing stage, which will lead to the sliding out of the pressure.
(2) the stage of hot pressing. The setting of temperature, pressure and time in the hot pressing stage plays a key role in the performance of epoxy laminates. It is set according to the curing condition of the ring rice adhesive, for example, the epoxy phenolic glass cloth laminates are set at 170-175 C, and the epoxy silicone glass cloth laminates are cured at (210 + 10) C. Because the thin plate is very easy to heat transfer, when the plate is pressed, the hot pressing temperature can be reduced by 5-10 degrees C, so that the plate has a certain elasticity for the use of the punching shear insulation parts and the lining insulation.
(3) after cooling off and discharging hot press, the hot plate is cooled in cold water and should be cooled slowly so as to prevent the internal stress and cause the warpage and deformation of the laminates, and the general cooling time is 30-60min. Then unload the pressure, open the hot plate, remove the product.
(4) after processing after more than 10 years of production experience in ZTELEC, we recommend that the laminates have heat treatment in the oven of 100-140 degrees centigrade to eliminate the internal stress of the laminates and the residual low molecular material in the plate, thus further improving the mechanical and electrical characteristics of the laminates.