Forming methods for continuously forming a polymer with a nano-scale surface texture

摘要

Disclosed is a method for forming a polymer to define a nano-scale sized surface texture onto at least part of the surface of said polymer so formed comprising: continuously depositing a polymer extrudate that is above its glass transition temperature from an extruder head onto a serially advancing lower moulding surface of a first mould in a manner that reduces, eliminates or minimises shear stress or other stress in said polymer extrudate so deposited by: heating the lower moulding surface to maintain the lower moulding surface at a temperature above the glass transition temperature of the polymer, the heated lower moulding surface maintaining the polymer extrudate above the glass transition temperature, the polymer extrudate being in or near a substantially liquid phase when being continuously applied to the heated lower moulding surface; matching the linear speed of the extrudate to the speed of the serially advancing lower moulding surface so that the deposited polymer is not moved across the lower moulding surface; applying a serially advancing upper moulding surface of a second mould to at least the exposed upper surface of the polymer while the polymer is maintained at a temperature above the glass transition temperature, the temperature of the lower moulding surface remaining sufficiently high to keep the polymer entering pressure forming zone above the glass transition temperature; and allowing the polymer to transition from above the glass transition temperature to below the glass transition temperature while within the pressure forming zone between the upper and lower moulding surfaces, wherein actively controlled heat removal occurs from said polymer via at least one of said upper and lower moulding surfaces when said polymer is in said pressure forming zone, to transition said polymer from above the glass transition temperature to below the glass transition temperature within the pressure forming zone; and providing a plurality of heat sinks for at least one of the upper and lower moulding surfaces, said heat sinks spaced relative to each other along the pressure forming zone, wherein a heat sink more advanced through the pressure forming zone is controlled to a lower temperature than an adjacent heat sink less advanced through the pressure forming zone in order to progressively reduce the temperature of the polymer as it advances through the pressure forming zone, wherein after said actively controlled heat removal the polymer is removed from the moulding surfaces. Also disclosed is an apparatus for continuously forming an extruded or co-extruded material of one polymer or more than one polymers to define a nanoscale sized surface texture onto the surface of said material.