Patent GB-613563-A (GB)
Title: Improvements in or relating to the production of decorative films
IPC: C08J7/02
Filed: 1946-06-17
Abstract: <PICT:0613563/IV(a)/1> <PICT:0613563/IV(a)/2> <PICT:0613563/IV(a)/3> <PICT:0613563/IV(a)/4> <PICT:0613563/IV(a)/5> <PICT:0613563/IV(a)/6> <PICT:0613563/IV(a)/7> A decorative film structure embodying an ingenerated design is obtained by bringing into contact with at least a portion of the surface of an organic-solvent-soluble film formed from plastic material, an organic fluid having a partial solvent and swelling action on the film, while the film is supported on a surface with that portion in contact with the liquid able to expand in a direction perpendicular to the normal plane of the film, but restricted as to planar expansion; allowing the fluid to act on the film until a portion of the film throughout its thickness distortively buckles and extends above the supporting surface; and setting the expanded portion of the film while it is in a state of expansion to provide the ingenerated design.  The setting of the design may be effected by application of pressure, or by casting a solution or gel of another film-forming substance upon the first film, and removing the swelling fluid.  Preferably, the secondary film-forming solution serves as the liquid for causing buckling of the primary film.  The two films may be such as to adhere permanently or such that they can be separated after the solvents are removed. The pattern obtained is dependent on the contour of the primary film and the depth of the swelling liquid containing the secondary film substance which is applied to the primary film. Thus, the peaks of the buckled film may rise above the level of the applied film-forming solution.  The swelling liquid may contain pigments, dyes, fillers, or fibres.  Pigments and dyes tend to settle in the depressions of the buckled film and thus give contrasting shades in the final product.  Fibres, or a fleece, web or fabric may be placed on the surface of the primary film and the secondary film may be cast through and upon the fibrous material so as to form a reinforced final product.  Such fibrous material may be of cotton or other organic material or of metal, glass or asbestos.  For carrying out the treatment, the film may be supported on a stationary or moving surface of glass, stone, metal or glazed paper.  The area to be treated may be held against planar expansion by securing the marginal edges of the film by tapes or clamps, or by means of a frame into which the swelling liquid is poured.  The adhesion between the film and its supporting surface must be sufficiently weak to permit vertical distortion or perpendicular expansion of the film upon the application of the swelling liquid.  The primary film may be of a polyvinyl chloride, polyvinylidene chloride, or polyvinyl butyral, which latter may be modified by addition of phenol- or urea - formaldehyde resin.  The secondary film may be a synthetic resin, a cellulose derivative, or a chlorinated or synthetic rubber.  A plurality of films may be cast one upon another or successively upon opposite faces of the primary film. Multi-colour effects may thus be obtained.  In an example, a clear polyvinyl chloride-acetate film is obtained by casting a solution of the polymer upon a paper sheet having a surface coating of thermoset urea-formaldehyde.  Upon the dried film, a solution of an unplasticized polyvinyl resin in methyl ethyl ketone containing a red dye is poured while the film and backing are positioned at 45 DEG  C. to the horizontal.  The solution flows down the first film and spreads over it as a thin film.  It then produces buckling of the first film and tends to accumulate in the depressions so that on evaporation of the solvent these areas are of greater thickness and depth of shade than the other parts.  One form of the buckled film A5 with the secondary film layer C5 is shown in Fig. 8.  As shown in Fig. 9, a composite material is formed by placing a rayon fabric F upon the primary film A7 and then applying the secondary film-forming liquid to a depth just sufficient to cover the fabric.  The peaks formed when the primary film buckles lift the cloth, but during subsequent drying the peaks collapse and the fabric becomes embedded in the secondary film.  As shown in Fig. 10, a sheet of felt F1 is applied to the face of the secondary film C4 while it is still tacky.  A composite material may be formed by placing two of the patterned films back-to-back with the secondary films C3 in direct contact with each other (Fig. 11b) and fusing them together or causing them to adhere by means of heat or a solvent, or a reinforcing fabric of open or close texture may be interposed between two of the films (Fig. 11a).  As shown in Figs. 12, 14, a primary film of thickness varying according to a definite pattern is subjected to the treatment. The swelling solution is applied to the ribbed surface.  Different swelling liquids may be applied to different areas a16 so as to obtain a number of different designs on the film.