Note: Descriptions are shown in the official language in which they were submitted.
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_ WO 01/81102 PCT/BE00/00125
METHOD FOR PRODUCING FLOOR AND WALL COVERINGS
WITH A DIFFERENTIAL GLOSS DECORATION EFFECT,
AND RESULTING PRODUCTS
Subject of the invention
The present invention relates to an improved method
for producing floor and wall coverings with contrasted, mat
and gloss decoration effects, which may be combined with
other decoration effects (designs, embossment, texture or
structure) that are standard for this type of product.
The invention also covers the products resulting from
this method.
Technical background
In order to satisfy customer demands, floor coverings,
in particular floor coverings of hard-wearing type, are
constantly changing both as regards the decoration, i.e.
essentially the design and the embossment (mechanical or
chemical Braining) and as regards the intrinsic wear
qualities (wear resistance, resilience, etc.).
The desired effects are of different nature but
generally involve an accordance (or register) between the
design, the embossment and any other optical effects.
In this latter respect, the tendency is to create,
preferably in accordance with a design and an embossment,
local effects that highlight specific areas relative to
others by means of differences in gloss.
To obtain mat and glossy effects, the state of the art
usually consists in locally Braining the product by
mechanical means with grainers that give different matting
effects.
The current performance requirement in terms of wear
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and resistance to chemical attack requires the application
of specific surface treatments with performance qualities
that are higher than those of the base products.
Unfortunately, the application of such surface layers
causes the matting effects obtained by mechanical Braining
to disappear.
Furthermore, the existing technologies for applying
surface treatments or layers, especially onto very wide
lengths, should be taken into account. The solutions
proposed should not, however, involve downgrading of the
existing material and prohibitive investments in new
equipment.
Document WO 99/39042 describes floor and wall covering
products with a contrasted gloss effect, containing at
least one layer with wear-resistant particles, such as
alumina.
The technique described involves the use of a curable
resin such as a urethane-based resin, depending on the
presence or absence of said particles.
This method requires at least one chemical Braining
operation and involves a partial overlapping layer applied
with a roller on the embossments of the product and having
a difference in gloss to create a contrasted effect. A
second solution recommended consists in applying a
continuous "topcoat" protective layer and a discontinuous
"topcoat" layer to the embossments.
This technique of applying a coating to embossments,
also known as "kiss-coating", is particularly difficult to
implement.
Poor adjustment of the equipment may lead to a
variation in the thickness of the product, which may lead
either to a loss of contact, or to crushing the embossment,
and, in both cases, prevents the desired effect from being
obtained.
A person skilled in the art can immediately see that
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this technique only allows the production of two grades of
gloss.
Aims of the invention
The present invention .aims to avoid the above
mentioned drawbacks. In particular, it aims to propose. an
economical method that is easy to implement and which
enables to produce a covering with mufti-contrast effect
and good wear resistance by a differential application of
different grades or qualities of "topcoat".
Other characteristics, details and advantages of the
present invention will appear in the following description,
of a preferred embodiment of the invention.
Characteristic elements of the invention
According to the invention, an underlying floor and
wall covering is first produced according to the standard
production techniques that are well known to those skilled
in the art, and gloss effects are then achieved by
differential application without total overlapping of at
least two protective layers of the "topcoat" type with
' different characteristics, possibly in register with the
underlying decoration.
With these techniques, products that incorporate
differential gloss effects in the protective layers of the
"topcoat" type are produced.
The underlying covering intended to receive the
decoration with a differential gloss effect may be smooth,
embossed by chemical or mechanical Braining, and may be in
a flexible or rigid form.
The decoration on the underlying covering may be
printed, made by inclusions of materials (inlaid) or even
obtained by other standard techniques. The products may
especially be produced on standard equipment for producing
floor coverings, up to a width of 4 m or more.
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The nature of the covering may consist of synthetic
materials such as PVC and polyolefins, semisynthetic
materials of the linoleum type, and may also be laminated
products or wood.
A first continuous or discontinuous application of a
first protective layer is first achieved on the chosen
underlying covering, followed by a drying operation.
A second discontinuous protective layer with a matting
effect that is different from that of the first layer is
then applied.
If so desired, the second layer may partially overlap
the first layer if it is discontinuous. There will
necessarily be such a partial overlapping when the first
layer is continuous.
Complementary matting effects (for example
intermediate between the glossiest layer and the mattest
layer) may be obtained either following the partial
overlapping of the first and the second layer, or by
applying one or more additional protective layers.
After each application of a protective coating layer,
a drying operation is performed. The drying may be
performed either using hot air or by IR-irradiation.
After drying, a curing operation is also performed,
preferably under irradiation with UV or with a beam of
electrons.
The differential gloss applications may or may not be
in register with the actual decoration of the covering
and/or may or may not be in register with the embossments
of the product.
The degree of gloss of the protective layers with
differential gloss effects may range between 5 and 90
(under 60 degrees).
The thickness of the layers thus applied may range
from 3 to 50 Vim.
The application of the various protective layers of
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differential gloss may be performed by means of one or more
of the following techniques (of course taking into account
the fact that it may be desired to produce the first
protective layer optionally in a continuous way):
5 - air knife;
- screen-printing application;
- heliographic application;
- flexographic application;
- roller coater.
In addition to their specific gloss characteristic,
the applied layers may also be coloured.
As will be described in greater detail hereinbelow,
the recommended technique allows to create mat-gloss
contrast effects with two or more than two different grades
of gloss.
The chosen protective layers contain coloured or
uncoloured resins that are conventionally used as topcoats,
so as to apply one layer of specific gloss contrasted with
the gloss of a neighbouring layer.
In contrast with the "kiss-coating" techniques, the
recommended technique also allows to coat both the depths
' and the crests of the embossment.
The resin contained in the protective layers is chosen
among standard curable resins, in particular resins that
are curable with W or with a beam of electrons, which may
be chosen from the group consisting of the following
resins: polyurethane, melamine, epoxy, acrylic or modified
ionomer, etc. Heat-curable resins may also be suitable,
although they are more difficult to use. The incorporation
of matting agents into such compositions does not
essentially reduce, and may even improve, the intrinsic
wear resistance properties, thus affording a very wide
range of techniques and products for the implementation of
the method.
The invention will be described in greater detail with
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reference to an illustrative embodiment and to examples for
implementing the technique of the invention, with regard to
the attached drawings.
Brief description of the drawings
Figure 1 illustrates the operating steps of. a
production line of the product according to the invention.
Figure 2 diagrammatically illustrates a cross-section
of a flat product obtained by a continuous method according
to a first embodiment.
Figure 3 corresponds to Figure 2 for a second
embodiment.
Figure 4 differs from the two preceding figures
essentially in that it relates to a product that is
embossed and also continuously produced.
Figure 5 diagrammatically illustrates a cross-section
of a product of the "wooden parquet flooring" type produced
by a discontinuous method.
In the various figures, identical reference numerals
are used for identical or similar constituent elements of
the products obtained.
Detailed description of one preferred embodiment of the
n...,r.- , ...~
The manufacturing line that is schematically shown in
Figure 1 involves the following operating steps:
- standard manufacture of the support 1;
- first application 2 of a polyurethane resin;
This application may be performed practically by any
common technique, by air-knife coating, by coating with
a roller, or alternatively by screen printing,
heliography or flexography;
- drying 3. It is possible to dry using hot air and/or
using an IR-heating installation;
- curing 4. The usual UV or electron-beam techniques are
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suitable for this purpose;
- second discontinuous application 5 of a polyurethane
resin by heliography or flexography;
- drying 6 especially using means identical to those of
step 3;
- curing 7, especially using means identical to those. of
step 4;
- third optional discontinuous application 8 of a
polyurethane resin.
It should be noted that the reference to polyurethane
is illustrative and that other resins or resin
compositions, in particular resins that are curable with W
or with a beam of electrons, may be suitable.
In Figures 2 to 5, the common reference numerals 10
generally designate a composite underlayer, the reference
numeral 20 designates a first "topcoat" layer which may be
continuous or discontinuous, depending on the case, and
which corresponds to the first application 2 in Figure 1,
the reference numeral 22 designates a second "topcoat"
layer, which is necessarily discontinuous and which
corresponds to the second application 5 in Figure 1, and
' the reference numeral 24 designates a second "topcoat"
layer corresponding to a third (optional) application 8 in
Figure 1.
In the case of Figures 2 and 3, the underlayers 10
may, for example, comprise a glass film 11 impregnated with
foam 12, a compact layer 13 and a standard wear layer 14.
This type of flat support 10 receives, in the case of
Figure 1, a continuous layer 20 of mat polyurethane, a
discontinuous layer 22 of high gloss and a discontinuous
layer 24 of intermediate gloss.
Figure 3 differs from Figure 2 in that the layer 20 is
discontinuous, the layers 22 and 24 nevertheless
overlapping the gaps in the application. of the layer 20.
In the case of the embossed product of Figure 4, the
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foam layer 15 has undergone a standard differential foaming
operation according to the "cushion-floor" technique. The
wear layer 14 follows the embossment, without filling it,
by means of a suitable and standard technique for applying
such~wear layers onto embossed products.
By these same techniques, a first "topcoat" layer.20
is continuously applied while preserving the embossment.
Layers 22 and 24 are then applied, for example solely
on the crests for 22 and in the depths and on the crests
for 24. Given that the layer 20 is continuous, it is
possible, as in the right-hand part of Figure 4, to leave a
space between the layer 24' and 22', both on the crest and
in the depth created by the layer 20, if so desired.
The case of a wooden parquet flooring according to
Figure 5 differs from Figure 1 only in the nature of the
underlayer 10, which is a composite material formed from a
bottom layer 16, an intermediate layer 17 and a sheet
(strip) of wood 18.
Illustrative embodiments
The formulations of the compositions used in the
' various examples are as follows.
Formulae A B C D E F
-Aqueous base aliphatic 100 100 100 - -
polyurethanea
-Aliphatic acrylate - - - 100 100 100
polyurethaneb
-Tripropylene glycol diacrylate° - - - 40 40 40
-Antifoamd 0.2 0.2 0.2 - - -
-Wetting agente 0.2 0.2 0.2 0.2 0.2 0.2
-Viscosity modifierf 0.5 0.3 0.2 - - -
-Matting agents - 2 3 - 2 4
-Photoinitiatorsh 2 2 2 - 2 2
These constituents are sold under the trade names or
brand names below by the manufacturers indicated.
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a. Neorad 8450 Zeneca
b. Ebecryl 294 UCB
c. TPGDA UCB
d. Byk 022 Byk Chemie
e. Byk 346 Byk Chemie
Fluorad FC 430 3M
f. Coatex Rheo 2000
Coatex
g. Acemat + s 100 Degussa
h. Irgacure 184 Ciba
Example 1 (flat product according to Figure 2)
The support is manufactured according to the standard
techniques that are well known to those skilled in the art.
The first PU (formula C) is continuously applied onto
the support using a roller coater (thickness 10 microns/mat
effect 15). The PU is dried with hot air.
The second PU (formula A) is then applied by the
heliographic technique (thickness 10 microns/gloss 80). The
PU is again dried with hot air.
The third PU (formula B) is applied by heliographic
roller in register with the design of the second PU
(thickness 10 microns/gloss 50). Drying with hot air.
The third PUs are finally cured under UV (power
160 W/cm) .
Example 2 (flat product according to Figure 3)
First PU (formula C) is applied by heliographic roller
(thickness 10 microns/mat effect 15). Drying with hot air.
The second PU (formula A) is applied by hello in
register with the first PU (thickness 10 microns/mat effect
80). Drying with hot air.
The third PU (formula B) is applied by hello in
register with the first and the second PU (thickness 10
microns/mat effect 50). Drying with hot air.
Final UV-curing.
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Example 3 (embossed product according-to Figure 4)
First PU deposit (formula F) continuously applied by
heliographic roller (thickness 10 microns/mat effect 15).
The PU is then UV-cured.
The second PU (formula D) is then applied by hello
(thickness 10 microns/gloss 80). UV-curing.
The third PU (formula E) is applied by hello in
register with the second PU and in register with the design
of the joint (thickness 10 microns/mat effect 50). UV
curing.
Final W-curing.
