Note: Descriptions are shown in the official language in which they were submitted.
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
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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
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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.
