1. Field of the Invention
The present invention relates to molds adapted to transforming plastic and composite materials, and the related transformation methods.
2. Discussion of Background Information
In the transformation of plastic and composite materials, and namely the transformation of reinforced or non-reinforced thermoplastic or thermosetting polymers, as well as vulcanizable compounds, there are numerous methods that consist of heating the material within a mold while pressurizing it, so that it can polymerize while taking on the mold impression. These transformation methods generally use the thermal conduction of the molds to bring the material to the temperature desired for its polymerization. Thus, the molds used are made from materials that conduct heat, on the one hand, and that withstand the temperature at which one wishes to heat the material, on the other hand.
The molds used in the prior art are therefore of two types: metal molds that conduct heat well and that easily withstand the high temperatures, and composite molds that only allow working at relatively low temperatures and with which one can only work certain plastic or composite materials that have low transformation temperatures. These various molds from the prior art have numerous drawbacks related to their implementation and to their use.
Metal molds are very expensive and require heavy investments. In addition, they rise in temperature and therefore cause problems in handling the demolded elements, problems in cooling and heating the elements and the molds, and therefore problems related to the cycle times. Also, the necessity of heating the entire mold requires a very substantial use of energy, particularly in the case of large sized elements. Composite molds are less expensive, but they are made of materials that do not resist high temperatures; therefore, they can only transform plastic and composite materials having a low transformation temperature. In addition, they degrade easily when the temperature rises, and they only allow a number of cycles that is very limited compared to metal molds.