Patent GB-658248-A (GB)
Title: Improvements in or relating to flexible film bearing a design and method for producing same
Inventor: CHAVANNES MARC A
IPC: B44C1/26
Filed: 1947-07-30
Abstract: <PICT:0658248/IV (a)/1> <PICT:0658248/IV (a)/2> A flexible film bearing a printed design is obtained by continuously advancing a smooth, non-stretchable, flexible carrier, printing a design of fluid film-forming substance of at least one colour on the carrier, forming a continuous layer of film over the design and the carrier from a fluid-forming substance comprising a dispersion or solution of a vinyl resin in a liquid containing a plasticizer, drying the film, and stripping the dried film together with the design from the carrier.  As shown in Fig. 7, a carrier 20 passes through tensioning rolls 21, 22, 23, and then over an engraved roller 24.  This roller dips into a film-forming liquid 25 and is rotated by the carrier. The roller carries a design in intaglio.  The design may comprise a plurality of small designs, or may be in the form of lettering, fine lines such as lacework, a silhouette, or dots such as a half-tone picture.  It may be continuous or discontinuous.  The liquid 25 may be a dispersion, emulsion, or solution of a vinyl resin, cellulose derivative, natural or synthetic rubber, paraffin wax or other wax, or a polyamide.  It may comprise a vinyl acetate-chloride copolymer, a plasticizer such as dioctyl phthalate, a solvent such as methyl ethyl ketone, and a pigment such as titanium white.  It may include dyes, phosphorescent or fluorescent substances, metallic flakes, carbon black, or chalk. The carrier receives a layer in design of the film-forming liquid 25, a doctor blade 27 being provided to remove liquid from the roller 24 except in the depressed regions.  The carrier may then pass over a heating roller 29 so as to dry the design.  If desired, several designs may be printed on the carrier in various colours.  The design may be applied using apparatus of the rotogravure type.  The carrier then passes through a coating apparatus where a layer of vinyl resin solution or dispersion is applied over the design.  The coating apparatus as shown comprises rollers 30-32 and a trough 33, partly formed between rollers 31 and 32.  The vinyl resin preparation may comprise a vinyl acetate-chloride copolymer, dioctyl phthalate as plasticizer, and a mixture of high and low boiling diluents including xylol and petroleum distillates.  If the film is required to have a smooth flat surface opposite to the designed surface, the carrier is passed from the coating device to a drying and fusing oven.  I an undulated surface is required, the carrier is passed through a short oven 36 and then swelling agent is applied to the partially dried film by a spray 37 so that the surface of the film becomes undulated.  The carrier is then passed through an oven 38 with drying and fusing sections 38a, 38b.  The dried film with the design layer is stripped by roll 45 and is wound on reel 46.  The vinyl resin composition for forming the body of the film may contain pigments, fluorescent or phosphorescent substances, and other additions.  The design and body portions of the film may be in contrasting colours.  If desired, the conditions of formation may be such that the design is deliberately smeared, e.g. the composition for forming the body portion may contain a good solvent for the design layer.  If desired, thin-walled jacket-like or bag-like articles may be obtained by applying the design layer to the carrier; then applying the vinyl resin composition over the design layer and carrier in the desired shape of one wall of the article; drying this layer; applying a coating of a substance which is relatively non-adhesive to this layer, leaving an area exposed, e.g. at the margin; drying this layer; applying another layer of film-forming substance over the non-adhesive coating and the exposed area of the first layer; drying this layer and stripping the article from the carrier.  If undulations are desired, a swelling agent is applied to the last layer while it is still in a partly dried condition.  Such a bag-like article is shown in Fig. 9.  Labels may be produced by applying appropriate designs to the carrier, forming a continuous film layer over the designs and then severing the film at the appropriate points to form the separate labels. If desired another film-layer may be formed over the film or article on the side bearing the embedded design.  A design in relief may be printed on the film on the side opposite to that bearing the embedded design.  Specifications 288,592, [Class 2 (ii)], 638,034 and 650,784 are referred to.  The Specification as open to inspection under Sect. 91 comprises also the production of films in which the body portion as well as the design portion is of any film-forming substance.  This subject-matter does not appear in the Specification as accepted.