GB2035206A

GB2035206A - Paper-plastics wallcovering

Info

Publication number: GB2035206A
Application number: GB7935880A
Authority: GB
Original assignee: Reed International Ltd
Current assignee: Reed International Ltd
Priority date: 1978-10-20
Filing date: 1979-10-16
Publication date: 1980-06-18
Also published as: GB2035206B

Abstract

In order to reduce curl of a wallcovering comprising a laminate of a paper backing and a plastics film the paper backing is arranged to be in the form of a plurality of spaced paper strips extending along the length of the wallcovering. The spacing between the strips is small (typically less than 0.5 mm). The plastics film may be metallised polyethylene terephthalate.

Description

SPECIFICATION Wallcovering This invention relates to wallcoverings comprising a laminate of paper backing and a plastics film. (By the term "wallcovering" we include products suitable for covering surfaces other than walls, for example ceilings).

Such wallcoverings are well known. The purpose of the paper backing is generally to confer bulk to the product so that, when applied to walls, minor surface imperfections thereon are concealed. The plastics film, which is often printed with a decorative pattern, confers an attractive surface which is suffi ciently strong to withstand washing, abrasion, etc.

The wallcovering is conventionally fastened to the wall by means of an aqueous adhesive paste, often starch based applied to the paper backing. In some cases the wallcovering is prepasted. Whether the wallcovering is prepasted or not the wallcovering becomes wetted during the hanging process. During such wetting the paper backing absorbs water and swells. This swelling acts in a sense to increase the dimensions of the backing, the increase in width in the direction transverse to the paper machine direction being typically of the order of 1 to 3%.

The plastics film is generally not affected by the water and so a situation is created in which one layer of a two-layer laminate system is stressed to expand more than the other layer and the situation does not fully recover when the pasted paper dries. This sets up an edge curling tendency rather than an overall curling tendency, the intensity of the curling being governed by such factors as the thicknesses, strengths, ductility of the components of the wallcovering. Where the plastics film is strong and the paper backing is thick (e.g. 100 g/m2 or more) curl is pronounced even to the extent that no normal wallcovering adhesive will retain the edges in adhesion with a wall.

One type of wallcovering having a strong plastics film is that in which the film is polyethylene terephthalate. This is a desirable material which can be metallised, but its strength accentuates edge curling problems.

Various methods have been proposed to improve the dimension stability of wallcoverings. However most of them give either increased costs or loss of paper-like properties.

We have now devised a wallcovering comprising a laminate of paper backing and plastics film in which the tendency to edge curl is overcome, or reduce to a level controllable with normal pasting techniques, and the paper-like properties maintained with little or no cost increase.

According to the present invention we provide a wallcovering comprising a laminate of a paper backing and a plastics film in which the paper backing comprises a plurality of spaced apart strips of paper extending along the length of the wallcovering, the spaces between the strips being small to the extent that the sum of the dimensions of the spaces is commeasurate with or less than the increase in transverse dimension of the paper backing when wetted.

By the use of a backing consisting of a plurality of spaced strips with small spacing, the necessary bulk is given to the wallcovering without significantly altering its handling, or effect, or covering ability whilst providing a wallcovering which, on wetting, hanging and drying does not result in edge curl.

The spaces between the strips should not be more than 1 mm, and preferably not more than 0.5 mm, to avoid the generation of an undesirable striated appearance to the face of the wallcovering.

For a paper backed, plastic film laminate wall covering of 530 mm width in which the paper backing swells on wetting by 3%, at least 17 strips are recommended having a width of about 30 mm. This leaves a spacing between strips of about 1 mm. If the spacing between strips is to be reduced to about 0.5 mm, then 32 strips are recommended, each strip having a width of about 16 mm. It is preferred however to use at least 50 strips.

Because of the discontinuous nature of the backing across the width of the wallcovering, the plastics film may be called upon to supply more of the transverse strength but this sets no problem and in fact may be in aid of strippability of the wallcovering.

Examples of suitable plastics films include polyethylene, polypropylene, polyvinyl chloride and polyethylene terephthalate.

The film is preferably an oriented film and particularly preferred is biaxially oriented polyethylene terephthalate. A decorative layer or pattern may be applied to the plastics film either before or after laminating to the paper backing. Such a decorative layer may be applied by printing.

Where the film is transparent the decorative pattern or layer may be applied to the surface of the film to which the paper backing is to be applied so that the plastic film serves as a protective layer to the decoration. One particular form of decorative layer that may be used is a metallic layer applied to the film by, for example, vacuum deposition.

A preferred wallcovering consists of a vacuum metallised biaxially oriented polyethylene terephthalate film to the metallised side of which the paper backing strips are laminated. In such a case, the non metallised surface of the film may be provided with a printed pattern.

The paper strips may be laminated to the plastic film by means of any suitable adhesive, an acrylic or nitro-cellulose lacquer or an ionomer or other hot melt adhesive. The adhesive, if applied all over the surface of the plastics film, may also act as a corrosion barrier e.g. to protect any metallic coating on the plastic film from attack by salts in the wallcovering hanging adhesive or that are leached out of the wall or ceiling to which the wallcovering is applied.

The wallcovering may be made by adhering the paper strips to an adhesive coated plastics film as it passes through a laminating nip. The paper strips may conveniently be produced by slitting a web of paper as it is fed from a reel to the laminating nip and may be spaced apart by the desired amount by means of guides or by a banana or spreader roller.

If desired a suitable wallcovering adhesive may be applied to the reverse side of the paper either before or after laminating to the plastics film.

The paper strips may have straight sides or may be of a curved or zig-zag configuration. In either case however the width of the strips and their spacing should be in accordance with the criteria specified hereinbefore.

The invention is illustrated by the following example: A 12 pm film aluminium metallised biaxially oriented polyethylene terephthalate of width 530 mm was coated on the metallised surface with an acrylic based adhesive applied at a rate of 10 g/m2.

While the adhesive was still wet the coated film was laminated to paper of substance 90 g/m2 which had been slit into 51 parallel straight sided strips of width 10 mm spaced apart by 0.4 mm immediately prior to laminating. The paper had an expansion factor of 0.03.

When the resultant wallcovering was pasted with a water activated cellulose ether wallcovering hanging adhesive, hung on a wall and dried, there was no tendencyforthewallcovering to curl and minor imperfections in the wall surface were concealed.

Claims

1. A wallcovering comprising a laminate of a paper backing and a plastics film in which the paper backing comprises a plurality of spaced apart strips of paper extending along the length of the wallcovering, the spaces between the strips being small to the extent that the sum of the dimensions of the spaces is commeasurate with or less than the increase in transverse dimension of the paper backing when wetted.

2. A wallcovering as claimed in claim 1 in which the spacing between strips is less than 0.5 mm.

3. A wallcovering as claimed in claim 1 or claim 2 in which the paper strips have a transverse expansion when wetted in the range of 1 to 5%.

4. A wallcovering as claimed in any one of claims 1 to 3 having at least one strip for each 10 mm of width of wallcovering.

5. A wallcovering as claimed in any one of claims 1 to 4 in which the plastics film is a biaxially oriented film of polyethylene terephthalate.

6. A wallcovering as claimed in any one of claims 1 to 5 in which the plastics film is metallised on the surface to which the paper backing is laminated.

7. A wallcovering as claimed in any one of claims 1 to 6 in which the plastics film is laminated to the paper backing by means of an adhesive layer applied over the whole surface of the plastics film.

8. A wallcovering as claimed in any one of claims 1 to 7 in which the spaced apart strips have nonlinear edges, for example of curved or zig-zag configuration.

9. A wall covered with a wallcovering as claimed in any preceding claim with the paper backing adhered to the wall.