NL8202829A - WALL AND CEILING CLADDING. - Google Patents

Description

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Wall and ceiling cladding.

This invention relates to wall and ceiling cladding of the type consisting essentially of foamed polyolefin film.

It has previously been suggested, for example, in British Pat. Nos. 1,220,053 and 3,306,373 and in

European patent application 0.001,807, to use foamed films of polyolefins, in particular of polyethylene, as a basis for wall and ceiling coverings (hereinafter referred to as "wallpaper" for short. In particular, European patent application 0.001,807 describes based on foamed films of low density polyethylene mixed with a small amount of ethylene copolymer mat polar groups, the cells of that foam being essentially all of the closed type, said abrasion resistance and printability such treatments are so advantageous, but in practice it has been found that such closed-cell polyethylene foam wallpaper readily creates air bubbles shortly after application if the wallpaper was pasted with conventional water-based adhesives. due to insufficient local adhesion of wallpaper to the wall.

It has now been found that this drawback can be overcome by providing these films over their entire surface and by providing small holes throughout the thickness.

Thus, the present invention provides a wallpaper which is a foamed thermoplastic polyolefin film, of which essentially all cells are of the closed type, and whose density is between 0.05 and 0.5 g / ml, which is characterized -noted by the fact that the film is provided with a large number of bores which all pass through the entire thickness of the film and which are distributed over its entire surface, such that 8202829 is - 2 ~ <...... ...... ............... ............................ 2 .................................................. ..............................

that on average there are 1 to 30 such penetrations per cm.

The foamed film can be of any thermoplastic polyolefin, including polymers and copolymers of ethylene (both high and low density), propylene, butene-3 and 4-methylpentene-1. Particularly suitable foamed films are those which consist entirely of ethylene homopolymer or of copolymers of ethylene with another monomer, for example with 30 to 70% by weight of one of the above mentioned other monomers. These films may also consist of mixtures of such ethylene homo- or copolymers with a small amount (eg 4 to 20% by weight) of other homo- or copolymer, for example a copolymer of ethylene with vinyl acetate.

The foamed film can be made in any manner known in the art. This generally includes the extrusion of the polymer or mixture of polymers in the molten state from a high pressure space to a lower pressure space, with a suitable blowing agent homogeneously distributed over the material prior to extrusion. The blowing agent can be a substance which develops a gas by chemical decomposition at the extrusion temperature, for example azodicarbonamide or a mixture of citric acid and sodium bicarbonate, but also a chemically inert liquid which is miscible with the polymer under the extrusion conditions and at said lower pressure it boils at a temperature which is at least 30 ° lower than the extrusion temperature. Suitable liquids are pentane, hexane, other petroleum fractions, dichloromethane and 1,3,2-trichloro-J, 2,2-trifluoroethane. The amount of blowing agent will generally be between 5 and 35% by weight of the polymer or mixture of polymers; the exact amount is determined by the density the foam must have. If an inert liquid is used as the blowing agent, a small amount of nucleating agent is advantageously added to the material to be extruded, which improves the uniformity of the cell structure of the final foam; Such a germinating agent can be subjected to a thermoset 8202829 i. - <.

- 3 - are a decomposable substance of the aforementioned kind, but are also a chemically inert compound whose critical temperature is lower than the extrusion temperature, for example nitrogen. Advantageously, the extrusion is effected through a ring-shaped nozzle, so that a tubular extrudate is obtained, which is then blown up, flattened and cut open to form a flat film.

Preferably, 5 to 20% by weight of opacifier is included in the material to be extruded, and more particularly a pigment having a high covering power such as titanium dioxide, calcium carbonate or barium sulfate,

The closed cells of the foam preferably have an average diameter between 0.01 and 1 mm.

If desired, the foamed film after extrusion can undergo a known surface treatment; in particular, it can be treated with corona discharges to improve printability. Such treatment may be limited to that surface which must be the decorative outer side of the wallpaper, but the back may also undergo that treatment to improve its adhesion to the wall. The decorative surface of the wallpaper can be printed with a suitable pattern using any conventional technique such as flexographic, lithographic or screen printing, or with relief or underprint.

Instead of or in addition to the printing, the foamed film can be given a relief by knownly passing it through the nip of a roller with a pattern of raised and lowered parts, with a counter roller that is either resilient (so that the rolling contact therein also forms the pattern) or be rigid and then carry a counter-pattern.

The foamed film immediately after extrusion preferably has a thickness between 0.2 and 3 mm, in particular between 0.3 and 0.6 mm. If the film then has to get a relief, the thickness in the recessed parts can be reduced to 50-75% of its original thickness.

8202829

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The holes with which the foamed film is provided have a diameter between 0.05 and 0.5 mm. The piercings may be in a regular pattern if desired, for example, as a grid of squares, 5 but preferably, in order not to detract from the final appearance of the wallpaper, they are randomly distributed over the surface. Preferably, there are on average between 1 and 25 punctures per cm of foil area. %

The bores can be easily inserted into the foamed film by passing the latter through the pinch of a rigid roller, the surface of which bears a large number of protruding tips or needles of appropriate cross-section and at mutually suitable distances, with on the other side a resilient counter roller, for example one that is made of felt or covered with it, so that the needles can penetrate all the way through the film. Preferably, the needles are positioned radially on the surface of the roll or roller so that the tendency to tear the film rather than neatly piercing will be minimal. The piercing can be best, before, simultaneously with or after the printing of the foamed film. However, if that film is also to receive a pattern, it is preferable that this operation come after piercing, since the deformation of the film by the pattern can very usefully mask any potential irregularities in the piercing pattern.

Puncturing can normally be accomplished very well on a film which continuously moves at a speed customary in printing and embossing wallpaper, between 20 and 200 m / min, so that all of these operations are suitable in a single pass of the paper. material can happen.

Perforated closed-cell wallpaper according to the invention brings the aforementioned drawback of a previously known closed-cell wallpaper (that they blister with a glue on water-based blisters) shortly after application. minimum back. They also have the advantage over the non-pierced wallpaper in the longer term that 8202829 * - 5 - any moisture that has entered the wall can escape through the wallpaper.

The wallpaper of the invention generally exhibits a water permeability between 1050 and 1890 2 g / m / 24 hours, compared to an egg permeability of 15-21 2 g / m / 24 hours for the same material before being pierced. The air porosity of the pierced material is usually between 0.3 and 3.5 liters / min. dm .cm water pressure.

The invention is now further explained, but not limited by the following example, with reference to the accompanying drawing.

A closed cell foam film (1) consisting of a mixture of 96-97% polyethylene and 4-3% ethylene / vinyl acetate ropolymer, 0.38 mm thick, 0.26 g / ml and cells of 0.03-0.3 mm, was passed through the nip of a pair of rollers, the counter roller (2) of which was covered with felt, and the other roller (3) covered over its surface with radially arranged needles (4). Each needle was 6 mm long and they were arranged symmetrically on the roller at a density of 25 per cm. The film was passed through the nip at a speed of 20 m / min. The holes thus made in the film were clearly visible, they were measured and found to be 0.3-0.4 mm at their widest point (near the surface of the film) and at their narrowest point (in the center of the film). the film) 0.36-0.19 mm in diameter.

The pierced material (5) was then embossed, with the film in the recesses compressed for about 20%. The penetrations were re-measured and now found to be 0.05-0.1 mm in their narrowest portions.

The water permeability was measured on this film both before and after puncturing, with the following results: 2

Film not pierced: 18 g / m / 24 nur 2 35 Film pierced: 1470 g / m / 24 hours »8202829

Claims (10)

1. Wall or ceiling covering, being a foamed film of a thermoplastic polyolefin, of which essentially all cells are of the closed type and the density of which is between 0.05 and 0.5 g / ml, characterized in that the the film is provided with a large number of holes which all pass through the entire thickness of the film and which are distributed over its entire surface, such that on average 2 per cm are between 1 and 30 such holes. 2. Wall or ceiling covering according to claim 1, the foamed foil of which consists of ethylene homopolymer. 3. Wall or wall covering according to claim 1, the foamed film of which consists of a copolymer of ethylene with 10 to 70% by weight of propylene, butene-1 and / or 4-methylpentene-1. 4. Wall or ceiling cladding according to claim 1, wherein the foamed film consists of a mixture of an ethylene homopolymer or copolymer with 4 to 20 wt.% Copolymer of ethylene and vinyl acetate. Wall or ceiling covering according to any one of the preceding claims, containing 5 to 20% by weight opacifier. . Wall or ceiling covering according to any one of the preceding claims. whose closed cells have average diameters between 0.01 and 1.0 mm. Wall or ceiling covering according to any one of the preceding claims, characterized in that the penetrations 30 have diameters between 0.05 and 0.5 mm. Wall or ceiling covering according to any one of the preceding claims, the bores of which are spread randomly over the surface of the film. Wall or wall covering according to any one of the preceding claims, characterized in that it averages 8202829 - 7 - • v ...... ..... 2 '........... . .............. ......... 'has 1 to 25 through-holes per cm of surface. 10, Wall or ceiling cladding mainly according to description and / or example. 8202829