Patent GB-1225552-A (GB)
IPC: B32B37/22
Filed: 1968-03-07
Abstract: 1,225,552. Coating. PHOTOCIRCUITS CORP. and J. P. THAMS. 7 March, 1968 [17 March, 1967], No. 11039/68. Heading B2E. [Also in Division G5] A base material in D provided with a pattern, e.g. by printing, embossing, etching, printed circuit manufacturing techniques, 2) coated with a layer of viscous, liquid, solvent-free or substantially solvent-free, hardenable material, 3) contacted with a temporary covering material non-adherent to the coating in its hardened state, the surface of the covering material being provided with the mirror-image of the desired surface texture, 4) treated to harden the coating, e.g. by applying heat or radiation, and 5) stripped from the covering material. The coating composition may be applied in its un-polymerised state and is polymerised or cross-linked after its surface has been brought into close contact with the transfer-surface of the temporary top-layer material. Suitable materials for use as the temporary covering are sheet material, films or foils consisting of polyethylene, polyvinylchloride, polyvinylfluoride, polyester, polytetrafluoroethylene and metals. A release agent may be employed for facilitating stripping of the temporary covering after the coating has been hardened. Alternatively a mould release film or foil or paper may be used together with a suitable backing. For the manufacture of name-plates, dials the coating composition is translucent or transparent. The finish, pattern or texture of the temporary covering may be produced by mechanical, chemical, photo-chemical or printing means. Preferably the top-layer material is arranged a distance from the original surface of the material producing a coating layer of a specified and closely controlled thickness. Coating materials mentioned are polyepoxides, polyester, melamine and carbamide resins, polyacrylics, polymetha-acrylics, polystyrene and mixtures thereof. In Fig. 1 apparatus comprises a conveyor. It 2 supporting articles 1 to be coated. Two transport rollers 3 and 3' are kept at a certain distance thereby controlling the thickness of the layer of coating material 4 formed. The roller 3' may be spring loaded and the thickness of the layer foil is controlled by the pressure between two rollers 3 and 3'. The roller 3' serves as a guide roller for the temporary top layer 5.. In Fig. 2 a similar arrangement is provided. A transport belt arrangement 6 is employed to feed the article to the coating section and the two sheets or belts 5 of temporary top-layer materials serve for providing further transportation. The transport roller 3 and 3' act as the guide-roller for application of the temporary top-layer material 5. In the examples: 1) a laminate having printed circuit conductors on one or both sides is coated with. a solvent free epoxy resin composition and subsequently provided with a temporary top-layer consisting of polyester film arranged at a distance from the laminate to produce a coating layer of thickness sufficient for encapsulating the conductors producing a plain surface; (2) a name plate is formed by embossing a sheet of metallised paper and coating its surface with a melamine-resin composition, the surface of the layer being provided with temporary top layer consisting of polyetrafluoroethylene arranged at such a distance to form a coating of a thickness sufficient to reach a smooth, level surface.