CA1183440A

CA1183440A - Method of making decorative laminated products such as tiles, panels or webs

Info

Publication number: CA1183440A
Application number: CA000402216A
Authority: CA
Inventors: Sven A. Ryden; Ulf L. Ahlstedt; Eduard Lussi
Original assignee: Tarkett AB
Current assignee: Tarkett AB
Priority date: 1981-05-05
Filing date: 1982-05-04
Publication date: 1985-03-05
Also published as: NO821452L; NO156855C; JPH0351579B2; SE435199B; DE3215684A1; ATA165782A; AT381064B; JPS581557A; DE3215684C2; FR2505257A1; GB2108426A; SE8102784L; NO156855B; NL8201781A; FI821540L; FI74906C; FI74906B; FI821540A0

Abstract

CANADIAN PATENT APPLICATION

OF

SVEN ARVID RYDEN
ULF LENNART AHLSTEDT
EDUARD LUSSI

FOR

METHOD OF MAKING DECORATIVE LAMINATED PRODUCTS
SUCH AS TILES, PANELS OR WEBS

Abstract of the Disclosure:

A laminated decorative tile particularly for floor-ing purposes, is made by forming a base layer of granu-lated cellulosic material in a matrix of fusible plas-tics, and placing on the base layer a thin decorative layer of cellulosic material with natural holes and re-cesses therein. After a film of fusible plastic has been applied on the decorative layer the laminate is hot press-ed and then immediately cooled in a cold press. The tile obtained has a pleasing appearance because the granules of the base layer have been forced up, in the hot press-1a ing operation, into the holes and recesses of the de-corative layer, filling out these holes and recesses.
In this embodiment the tile has a smooth wear resisting layer surface but this surface can be provided with a relief pattern such that it conforms to the structure of the decorative layer, if the tile after cooling is heated in a free state, i.e. without press plates.

1b

Description

11~934~

This invention relates to a method of making decora-tive laminated products in tile, panel or web form.
Decorative coating or covering materials are produced in a multitude of embodiments and may consist for instance of synthetic or natural materials or combinations thereof.
The materials may present a smooth or relief wear resist-ing surface. Mostly, the latter alternative is preferred for both practical and æsthetical reasons. Relief ma-terials have a three-dimensional appearance rich in con-trast, but to produce this appearance the pattern and relief must be perfectly synchronized. An ordinary re-lief embossing to which the plastics surface is subjected and which is not in good register with the printing pat-tern does not bring about the above-mentioned effect.
Apart from all wood imitations in plastics, excel-lent cork imitations with relief surfacing have been made during the last few years. Like all pure natural materials, such imitations are usable for both wall cover-ing and flooring purposes. As for coating and covering materials comprising a combination of natural and syn-thetic materials in the form of a relatively thick plas-tics sheeting covering the natural material, conditions are slightly different in that these coating and covering ma-terials are only available with a smooth wear resisting surface since one has not succeeded in developing any method of securing a thick wear resisting plastics layer on, for instance, cork without neutralizing the relief effect at the same time.

3~

Such smooth cork flooring tiles, which have been manufactured for a great many years, are composed of a wear resisting layer of plastics, a decorative layer, a resilient layer and a base layer. The wear resisting layer preferably consists of a calendered or coated plas-tisol of transparent softened PVC of high resistance to wear and stain repellency. ~he resilient layer con-sists of a sheet made by lathe-turnin~ or splitting blocks of cork granules This sheet is, if necessary, refined by prelamination with a thin decorative cork veneer.
The base layer serves as a mechanical stress relieving means and said layer or a further layer complementary of the wear resisting layer counteracts dishing of the tiles and delays diffusion of moisture from the sub-floor.
For the last-mentioned layer use is made of a softened PVC film which has the same modulus of strength as the wear resisting layer or a higher modulus than said layer.
This will result in a balance of forces in the finished floor structure and ensure that the tiles remain planar.
Cork is a material which is excellently suited for the purpose concerned~ but its enormous porosity and air content give rise to problems at the tile manufacture.
Being a natural product, cork besides suffers from nu-merous defects which appear as big or small holes and recesses that are not acceptable in thè finished tiles.
This necessitates a severe selection and implies expen-sive waste in the production. Especially thin cork ve-neers of but little compression are usually strewn with ~83~

holes which must be stopped up before the sheets can be provided with laminates.
The wear resisting layer is usually united with the underlying layers by pressure gluing. One has also tried to manufacture cork webs continuously includinq varnishing and roll gluing, but these experiments have not met with any great success.
Summarizing, it may be established that natural materials combined with a wear resisting layer of plastics film occur only in the form of cork tiles with a smooth covering film layer~
The object of the present invention is to permit, by the use of a novel manufacturing method, making both smooth and relief tiles, panels and webs of this type, which are suited both as wall coverings and floorings and which in view of the insignificant waste are cheaper than the products hitherto made.
The object of the invention is realized by granulat-ing a eellulosie material, partieularly cork, mixing the granulate with a fusible plastics and making a mat therefrom, cutting from a cellulosic material of the same kind as or another kind than the first mentioned eellulosie material thin slices whieh in the state obtain-ed with the through holes and recesses therein are placed on the mat thus made, applying a film of fusible plastics on the thin slices of cellulosic material and compressing the laminate thus obtained under supply of heat for melt-ing the plastics and urging the material of the mat into ~ 4 ~334~

the holes and recesses of the slice, and then cooling the compressed tile.
The most characteristic feature of the method ac-cording to the invention is the use of an entirely new type of base layer which consists o~ granulated cellu-losic material in a matrix of fusible plastics. If ~he cellulosic material is cork and the base layer has a thickness of about 2 mm, the particle size must not ex-ceed 2 mm and is preferably below 1.5 mm. When at the manufacture of the tile, panel or web the thin decorative layer is placed on said base and the layers are subject-ed to a compressing operation at such a temperature that the plastics cures/melts, the plastic mass with its cork filling will "rise" into and fill out the holes and re-cesses of the decorative layer~ whereby a decorative layer with a smooth surface and perfect appearance is obtained. The filling material can be given any desired nuance, for instance a nuance which more or less conforms with the predominant nuance of the decorative layer or contrasts with said nuance.
The wear resisting layer which normally consists of a precoated 0.5 mm film of softened PVC, is placed on the decorative layer before said layer is united with the base layer, i.e. all three layers are united with each other in the same operation. In the compressing operation the wear resisting layer is thus also molten so that it well adheres to the decorative layer. The wear resisting layer may also consist of a coating ma-terial other than a film, such as a plastisol, differentkinds of lacquers, polyurethane etc.
After the product has been compressed for a prede-termined time it is transferrea to a cold press in which it is cooled and simultaneously subjected to a higher pressure, suitably approximately twice as high as that in the hot press The tlle, panel or web which is removed from the cold press, has the above-mentioned advantageous appearance and an entirely smooth wear resisting surface and is usable for wall covering and flooring purposes.
To provide a tile, panel or web with relief surface there is required a natural material having, what may be called, a "memory of its resilience". Cork is such a material. The cork with its peculiar cellular system is compressed when subjected to pressure but once the load has been relieved it partially springs back after some time lag. As the load in the above case is not re-lieved until the plastics has cooled off, the state of tension of the cork is blocked so that the tile, panel or web obtains the smooth wear resisting layer face.
If, however, the tile, panel or web is subjected after cooling to heating in a free state (i e. without being acted upon by the press plate or like means) to a tem-perature exceeding the softening temperature of the plas-tics, the state of tension Gf the cork relaxes and the cork returns to the shape it had before the pressing operation If use is made of softened PVC~ a reheating temperature of 70-150C is suitable. After reheating ~he tile~ panel or web is allowed to cool, likewise in a free state By this change of state one ob~ains a re-lief wear resisting layer face of very advantageous ap-pearance, since the relief of the wear resisting layer is controlled by the material of the decorative layer, whereby a perfect synchronization of pattern and relief is obtained.
As hinted at in the foregoing, the cork has proved extremely advantageous for the manufacture of a tile of natural material having a relief face, in which the decorative appearance depends upon the structure and composition of the thin layer or veneer employed. The layer is produced by splitting a block of cork conglo-merate into thin sheets which display a range of diffe-rent growth zones of varying relative orientation and compressibility. The different zones possess varying resilience and restorative capacity, whereby the relief formation can vary from simple knottiness to a perfect work of art of nature. Although cor~ is the most suitable ma'erial for the time being, other cellulosic materials are also conceivable, that have or may be given the "me-mory of resilience" required for the relief formation.
Applying the method according to the present inven-tion, one gains the special advantage that no cellulosic material is wasted, as all waste is converted into gra-nulate. This of course entails savings of cost beyond those obtained because the decorative layer need not be stopped up and there is only an insignificant discard of finished products :`~Li83~

tile, panel or web manufactured in the above-described manner and having a base layer of granulated cellulosic material in a matrix of fusible plastics, a thin decorative layer on the base layer and a wear resisting layer of a plastic film of fusible plastics, which latter layer by a cold pressing operation after the hot pressing has a smooth upper face or by renewed heating in a free state after the cold pressing operation has a relief surface, is highly decorative and extremely advantageous in use because it is both wear resistant and comfortable to walk on owing to its resilience and ~ insulating capacity.
; The invention will now be more fully described with reference to an example.
A 1 mm thick cork veneer was placed on a calendered

2 mm base layer of softened PVC and cork granulate hav-ing a particle size of up to 1.5 mm, and a 0.5 mm thick wear resisting layer film of softened PVC was then placed on said cork veneer. The material was put into-a press mould having distance means and provided on both sides with paper coated with a mould release agent. The press-ing operation was performed in a hot press (180C) under successively increasing pressure up to 2 kg/cm2 for five minutes. The mould with the material contained therein was then transferred in hot condition to a cold press where the pressure was increased from 2 kg/cm2 to 5 kg/cm2 for five minutes, whereupon the cold product was removed from the mould. The product now was entire~ly planar~

but at the subsequent ileating to 130C for two ~inutes a relieE pattern was Eormed on the surface~ the appear-ance of which was determined by the structure used for the cork veneer.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of making decorative laminated products, such as tiles, panels or webs, characterized by granulating a cellulosic material, mixing the granulate with a fusible plastics and making a mat therefrom, cut-ting from a cellulosic material of the same kind as or another kind than the first mentioned cellulosic material thin slices which in the state obtained with the through holes and recesses therein are placed on the mat thus made, applying a film of fusible plastics on the thin slices of cellulosic material, and compressing the lam-inate thus obtained under supply of heat for melting the plastics and urging the material of the mat into the holes and recesses of the slice, and then cooling the compressed tile.

2. A method as claimed in claim 1, characterized by effecting the cooling of the product in a cold press in which the tile is subjected to a higher pressure than in the hot pressing operation.

3. A method as claimed in claim 1 or 2, charac-terized by subjecting the tile after cooling to free heating and cooling for relief formation of the plastics film.

4. A method as claimed in claim 1, characterized in that at least the cellulosic material is cork.

5. A method as claimed in claim 1, characterized in that at least the granulated cellulosic material is wood.

6. A method as claimed in claim 1, characterized in that the plastics are softened PVC.