GB2156396A

GB2156396A - Filament reinforced plastics sheets

Info

Publication number: GB2156396A
Application number: GB08507345A
Authority: GB
Inventors: Eskil Sigfrid Lundquist; Per Magnus Lennart Ronnmark
Original assignee: Tarkett AB
Current assignee: Tarkett AB
Priority date: 1984-03-23
Filing date: 1985-03-21
Publication date: 1985-10-09
Also published as: DE3509913A1; JPS60212341A; SE451440B; GB8507345D0; SE8401624D0; FR2561578A1; SE8401624L; GB2156396B

Abstract

A reinforced web or sheet of plastic is characterized in that the reinforcement consists of separate substantially parallel threads or filaments which extend in one direction in the web or sheet and are arranged with predetermined spacings. The web or sheet is produced in that the threads or filaments are stretched or placed over a mold surface in the above-mentioned arrangement, whereupon plastic material is applied thereto and gelatinized, fused or otherwise treated depending on the plastic material used, in intimate contact with the threads or filaments. Alternatively, the reinforcement may be produced as a separate unit by permanently or detachably fixing the threads or filaments of the above-mentioned arrangement on a carrier.

Description

SPECIFICATION A method of making reinforced webs or sheets of plastic and a web or sheet produced according to the method The present invention relates to a method of making reinforced webs or sheets of plastic, in which method the reinforcing material is spread over a mold surface and plastic material is applied over it and is gelatinized, fused or otherwise treated in intimate contact with the reinforcement in order finally to be removed from the mold surface together with said reinforcement.

Plastic webs or sheets are often reinforced in order to increase the mechanical strength and the dimensional stability. The reinforcement also gives a more planar product and a product with increased stiffness. Another advantage of using a reinforcement is that the strength of the product increases during the manufacturing process. Normally, the reinforcement is in the form of a woven fabric, threads arranged in specific patterns on a carrier or a felt of non-woven material, and may consist of glass, polyester, jute, polyamide, polypropylene, cellulose, rayon, carbon fibres, polyaramide, metals etc in pure or mixed form.However, the reinforcement involves a substantial cost increase in the manufacture of the products because of the costs relating to the reinforcing material per se, the manufacture of the woven fabric or the felt, and the binder required for holding the fabric or felt together. In some cases, the binder also entails undesirable side effects.

The object of the present invention is to make reinforced plastic webs or sheets in a novel, less complicated way which will reduce costs without impairing the properties of the product and which, in some contexts, entails new, advantageous properties. According to the invention, this object is achieved in that the reinforcing material consists of separate threads or filaments which are stretched or placed over the mold surface in one direction substantially parallel to each other and are maintained in place with predetermined spacings by means of reed-like means or rolls with circumferential grooves.

Normally, use is made of release paper which is applied to the mold surface, the threads or filaments being stretched or placed over the release paper in contact therewith, whereupon the plastic material in the liquid state and/or in the form of a sheeting is applied to the threads or the filaments.

The advantage of the above-mentioned method is that the reinforcement can easily be adapted to the prevailing requirements regarding the strength and dimensional stability of the finished product, such that the amount of reinforcing material can be minimized. The reduction of the amount of reinforcing material means that the amount of plastic material required for impregnating it will also be reduced. The fact that the reinforcing material extends in one direction only generally has no adverse effect on the strength and dimensional stability of the final product. For reinforcing certain products, it may of course be necessary to use a woven fabric or a felt according to conventional technique.In the case of a product manufactured in large volumes such as wall-lining materials, a new type of reinforcement however confers the advantage that lengths of material that are fixed on a wall with the reinforcement vertically oriented can be slightly stretched in the horizontal direction, whereby gaps which exist between the lengths and are caused by irregularities in the supporting surface can be bridged.

According to the above, the reinforcing material consists of threads or filaments. In this context, the term "threads" refers to both threads with long and short fibres and bundles of threads or fibres and so called roving. The reinforcement may consist of any suitable material, e.g. any of those mentioned by way of introduction.

According to the above, the reinforcement is supplied to the mold surface on which the product is manufactured. Devices used in the textile field, such as reed-like means or special rolls with circumferential grooves can be used for maintaining the reinforcing threads or filaments in place. The threads or filaments can be stretched along the mold surface or merely be placed thereon (compare products of prestressed and non-tensioned reinforced concrete).

According to another aspect of the invention, the reinforcement can be produced by a special operation in that separate threads or filaments extending in one direction and substantially parallel to each other are permanently or detachably fixed on a carrier with mutual spacings determined by the requirements regarding strength and dimensional stability to be placed on the finished product. A reinforcement provided in this way can be handled as the woven fabrics or felts hitherto used, and no modification of the mold or the like in which the product is made, is necessary. The carrier may consist of release paper, in which case the reinforcement adheres to this paper by as small a force as possible, so that it can be removed after the product is finished. The carrier with the reinforcement may also be kept on the finished product to form e.g. a backing in floor tiles.

The invention also relates to a web or a sheet of reinforced plastic material which is characterized in that the reinforcement consists of substantially parallel threads or filaments which extend in one direction and are arranged with mutual spacings depending on the requirements regarding strength and dimensional stability to be placed on the web or the sheet.

The invention will be described in greater detail hereinbelow with reference to an Example concerning vinyl wallpaper. The plastic materials as exemplified are of a type well known to the expert and the plastic recipes will therefore not be specified.

Example of the manufacture of vinyl wallpaper.

From 500 reels, a roving was drawn through a reed so as to obtain a roving with a spacing of 4 mm, and between rolls into engagement with a web of release paper. The weight of the resulting reinforcement was 25 g/m2. The reinforcement extending over the release paper was coated with a plastisol so as to cover the fibres of the roving.

This plastisol may contain 0-60 % of inorganic filler and may also be pigmented and provided with a substance decomposable by the supply of heat, such that it can be expanded after gelatinization.

After the gelatinization, the release paper, which may be used several times for the same operation, was removed. For producing the vinyl wallpaper, the parallel-reinforced layer was covered with a plastisol layer suited for printing, this layer being gelatinized and cooled, whereupon the resulting substrate was supplied to a printing machine, in which it was provided with a decorative print. The printed substrate was finally provided with a transparent surface layer of PVC.

In use, the finished wallpaper could not be stretched in the longitudinal direction, which is essential for ensuring pattern alignment between different lengths of wallpaper, but, as pointed out above, was flexible in the transverse direction, this making the wallpaper easier to correctly apply to a wall.

As in the above-mentioned Example of making a vinyl wallpaper, it is possible to produce vinyl flooring by placing parallel bundles of glass fibres, polyester fibres or mixtures thereof, optionally together with cellulose-based fibres, on a release pa per or any other temporary carrier, whereupon plastisol or a thermoplastic sheeting is applied.

After the plastisol, fibre bundles and sheeting have been fused together, the release paper or carrier is removed. To this substrate is then applied a layer which is suited for printing. This layer may be provided with a blowing agent for chemical stamping according to known technique. After conventional printing, the printed surface is coated with PVC plastisol or is laminated with PVC sheeting to a thickness of 0.05-1.5 mm, preferably 0.2-0.9 mm.

The back of a thus manufactured floor tile is suita bly provided with a layer of expanded plasticized PVC which serves to provide for sound damping and enhanced comfort when using the flooring.

The parallel reinforcement gives dimensional stability in the longitudinal direction of the flooring web, such that the decorative print on the different lengths of material will have the same repeat, whereby the lengths can be placed edge to edge with accurate pattern alignment. The flexibility of the flooring web in the transverse direction makes it easier to adapt the flooring material to premises of complicated geometry.

The reinforcement according to the invention may of course be used for producing many other products as well, such as roofing material which will thus be perfectly straight but, because of the flexibility in the transverse direction, can also be placed on supporting surfaces which are not com pletely planar.

Claims

1. A method of making reinforced webs or sheets of plastic, in which method reinforcing material is spread over a mold surface and plastic material is applied over it and is gelatinized, fused or otherwise treated in intimate contact with the reinforcement in order finally to be removed from the mcld surface together with said reinforcement, characterized in that the reinforcing material consists of separate threads or filaments which are stretched or placed over the mold surface in a direction substantially parallel to each other and are maintained in place with predetermined spacings by means of reed-like means or rolls with cir cumferential grooves.

2. Method as claimed in claim 1, characterized in that release paper is applied to the mold surface and that the threads or filaments are stretched or placed over said release paper in contact therewith, whereupon plastic material in the liquid state and/or in the form of a sheeting is applied to the threads or filaments.

3. Method of making a reinforcement for webs or sheets of plastic, characterized in that separate threads or filaments extending in one direction and substantially in parallel with each other are permanently or detachably fixed on a carrier with mutual spacings determined by the requirements regarding strength and dimensional stability to be placed on the finished product.

4. A web or sheet of reinforced plastic, characterized in that the reinforcement consists of substantially parallel threads or filaments which extend in one direction and are arranged with mutual spacings depending on the requirements regarding strength and dimensional stability to be placed on the web or sheet.

5. A method of making reinforced webs or sheets of a plastics material substantially as herein described.

6. A web or sheet of reinforced plastics material substantially as herein described.