Patent ID: 6217700
Filing Date: 2001-04-17
Classification: B29C

Abstract:
In a method of manufacturing thermoset webs of thermoplastic polymer material particles, in which the thermoplastic polymer material particles are continuously poured in a surface-covering manner to form an initial layer directly onto a heat-resistant lower conveyor belt, and in which the initial layer then successively travels through a preheating section, a heating section and a cooling section of a treatment area, wherein the polymer material particles are covered at least in the heating section and in the cooling section from the top by an upper conveyor belt, the improvement comprising the steps of:a) uniformly pouring the thermoplastic polymer material particles mixed with binder or without binder by means of at least one first material distributor arranged above a front, non-covered portion of the lower conveyor belt to form the initial layer with a predetermined thickness;b) maintaining a distance between the lower conveyor belt and the upper conveyor belt in the heating section and in the cooling section equal to the thickness of the web to be manufactured;c) applying the initial layer with such a thickness onto the lower conveyor belt that the thermoplastic polymer material particles during travel thereof between the lower and upper conveyor belts in the heating and cooling sections are subjected to a minimum pressure of at most 0.2 bar, and guiding the upper and lower conveyor belts in heating and cooling sections such that temporary deviations from the predetermined thickness of the initial layer do not result in the minimum pressure being exceeded;d) bonding together the thermoplastic polymer material particles essentially without pressure in the heating section to form the thermoset web and simultaneously subjecting the web to surface smoothing; ande) once again smoothing the surfaces of the web by means of at least one pair of smoothing rolls acting on the lower and upper conveyor belts and mounted between the heating section and the cooling section.