Patent ID: 6511734
Filing Date: 2003-01-28
Classification: B29C,Y10T

Abstract:
Process for manufacturing a surface-structured semi-finished multi-layer film product from a thermoplastic, said process comprising the following steps:applying at least two layers of a thermoplastic material in melted form or in the form of a laminate film onto a surface formed by a metal roller with a separate external coating, said surface having an adjustable temperature and providing a negative structure (matrix) for the desired product, the plastic material having a lower layer of lighter, freely-flowing polymer in contact with the surface and an upper layer of heavier, more viscous polymer, wherein the surface has low adhesion to the plastic material and is provided with numerous fine cavities in the form of blind holes which are laser-drilled in the coating covering the roller, and wherein the surface is maintained at the melting temperature of the lower layer of plastic material at least in the area of initial contact; forcing the lower layer of the plastic material into the surface under compression of the remaining volume of plastic material, so that the matrix is filled, but the fine cavities are only partially filled by the plastic material, wherein the pressure on the plastic material is applied by a second roller in a roller gap; solidifying the shaped, plastic material by cooling while still in contact with the surface, wherein it assumes the corresponding surface structure; releasing the pressure on the plastic material, wherein the air compressed within the fine cavities at least partially forces the plastic material out; removing the hardened plastic material from the surface as a structured film, wherein the plastic material which is inserted into the cavities and removed from the same forms a pile comprised of projections and naps.