DE1096036B - Process for matting the surface of polyethylene terephthalate films - Google Patents

Description

The present invention relates to the treatment of polyethylene terephthalate films, and in particular to a method for producing a matted or dull surface on such films.

According to the invention a method for matting the surface of polyethylene terephthalate films, wherein the film in contact with an aqueous solution of potassium or sodium hydroxide for at least that long is brought until the surface gloss of the film has disappeared, in such a way suggested that only one Surface of the film is brought into contact with the solution, while the opposite surface is temporarily is glued to a carrier.

It is preferred to work with a solution of potassium hydroxide, as this is the most important in the reaction Products that occur with the film surface can be removed more easily by washing than with the reaction products is the case with sodium hydroxide.

The intensity of the treatment depends on the temperature, the concentration of the solution and the length of time in contact with the film surface. These factors can be varied within wide limits, but they should be balanced to produce the desired amount of modification of the film surface. For example, when working with a 50gewichtsprozentigen aqueous solution of potassium hydroxide at a temperature of 120 to 130 ⁰ C, a considerable matting takes place of the film surface when the film for 1 minute dipped in the solution, while at a temperature of 140 ⁰ C. dissolution of the film takes place in the solution. A concentration of 30 to 60 weight percent sodium or potassium hydroxide generally represents a useful concentration, in particular when operating at temperatures between 90 and 13O ⁰ C, since in this case the film can be treated using high operating speeds.

A polyethylene terephthalate film can be applied to any surface of the carrier, so that one surface of each film is simultaneously with the alkali can be treated.

The intensity of the treatment can be varied to produce a wide variety of products, and in the area of films that are still transparent, but have lost their surface gloss, up to Films in which the treated surface is white and has a distinct roughness.

The products according to the invention can be used in various ways. For example film surfaces treated in this way are written on with a pencil or ink, and they can be used as a replacement for canvas or for other drawing, writing or copying purposes, being the degree of transparency of the material from methods of matting the surface of polyethylene terephthalate films

Applicant:

Imperial Chemical Industries Limited,
London

Representative: Dipl.-Ing. A. Bohr, Munich 5,

Dr.-Ing. H. Fincke, Berlin-Lichterfelde, Drakestr. 51,

Dipl.-Ing. H. Bohr and Dipl.-Ing. S. Staeger,

Munich 5, patent attorneys

Claimed priority:
Great Britain 29 November 1957

Norman New, Welwyn Garden City,
Hertfordshire (UK),
has been named as the inventor

depends on the intensity of the previous treatment. The films can also be used as non-reflective protective surface coverings, for example when they are applied in film form to appropriate materials such as wood, fabric, paper or plastic materials including flexible plastic sheets. Such non-glossy and abrasion-resistant products are, for example, wall coverings, bricks and paper, upholstery fabric, plastic for the production of handbags and luggage, and book covers. The method can also be used to improve the adhesive properties of polyethylene terephthalate films with respect to covering compounds, for example with respect to heat protection coatings, and to improve the adhesion of multilayer material which contains a polyethylene terephthalate film layer and which is said to have particularly good mechanical properties. This is the case, for example, with conveyor belts and drive belts which contain a polyethylene terephthalate film in the multilayer material in order to ensure the tensile strength and length stability of the belt in question. In the case of multilayer materials of this type, it is therefore not important that the treated polyethylene terephthalate surface is absolutely visible in the finished product.
The invention is illustrated in the following example.

009 680/538

Example.,

A piece of 0.006 mm thick plane-oriented crystallized polyethylene terephthalate film was «on one side with a pressure-sensitive adhesive. A multilayer material was produced, 5 ' by placing the pretreated film on the surface of a 0.127 mm thick film of the same material was applied. This multilayer material was soaked in a 50 weight percent solution for 20 seconds of potassium hydroxide immersed in water at a temperature of 130 ± 1 ° C. The product was after this treatment with water, then washed with acetone and then dried. That way it was removes the gloss of the outer surfaces of the thinner films without affecting the transparency of the film was significantly affected. The outer films were then removed from the base film and without further treatment to create a protective layer on the surface of decorative wall coverings used.

Claims (4)

Patent claims: 1. Process for matting the surface of polyethylene terephthalate films, the film being brought into contact with an aqueous potassium or sodium hydroxide solution until the surface gloss of the film has disappeared, characterized in that only one surface of the Füjns with the solution is brought into contact while the opposite surface is temporarily adhered to a carrier. 2. The method according to claim 1, characterized in that a 30 to 60 percent by weight potassium or Solution containing sodium hydroxide is used. 3. The method according to claim 1 and 2, characterized in that the film is placed with the solution at a temperature between 90 and 130 ⁰ C in contact. 4. The method according to claim 1 to 3, characterized in that the film so long with the potassium or Sodium hydroxide solution is brought into contact with that after washing and drying can be written on with a graphite pencil. Considered publications:
German Auslegeschrift V 6119 IVc / 39b (published on October 11, 1956). © 009 680/538 12.60