Note: Descriptions are shown in the official language in which they were submitted.
2~33378
COATING SYSTEMS FOR PROVIDING SURFACES WITH CHROMATIC DECORATIVe
EFFECTS IN RELIEF
State oP the art
The following method is normally used to obtain coated objects
with special chromatic ePPects: a coating layer is spread over the
surPace to be coated, the system is cross-linked and/or dried and a
second coating layer different from the first is then spread over
the dried coated surface, the cross-linking and/or drying operation
being then repeated to obtain the desired effect. In this manner,
coated surfaces with a very wide range of polychromatic efPects can
be prepared industrially.
It is not known to be able to obtain such polychromatic decorative
effects, including relief effects, by the simultaneous or quick-
succession application of two or more different coatings before the
initially applied coating has dried.
Description of the invention
A process constituting one aspect of the invention has been
discovered which enables coated surfaces with chromatic decorative
effects in relief, to be obtained by applying at least two different
coatings to the surface. These different coatings are applied
simultaneously or in quick succession, within 1 to 5 seconds. In
this latter case the successive coatings are applied on the first
coating before this has dried (wet on wet~.
The essential condition to enable the process of the invention to be
effected is that the coatings have such physico-chemical
characteristics that diffusion of the coatings into each other is
totally prevented or at least considerably limited.
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A further aspect of the invention is therefore represented by
combinations of coatings which do not diffuse substantially into
each other and which when spread simultaneously or in quick
succession over the object to be coated give rise to chromatic
decorative effects in relief.
A further aspect of the invention is represented by the coated
objects with chromatic decorative effects in relief obtained by
using the aforesaid coatings and process.
To prevent mutual diffusion, the constituent coatings of the coating
systems according to the invention must satisfy well defined
requirements.
An essential requirement is incompatibility of the constituent
coatings of the system. This occurs for example iP one of the
coatings is a physically driable coating or an unsaturated polyester
resin-based coating and the other a water-based coating.
If the coatings are compatible, mutual diffusion can be prevented by
special additives which produce substantial differences in the
viscosity and/or surface tension and/or specific gravity of the
coatings, so making them incompatible. The differences in said
physical properties produce interaction between the two coatings to
prevent their diffusion, by which particular decorative effects in
relief are produced, with a wide range of chromatic variations.
Additives which induce substantial viscosity differences are for
example micronized silicas of Aerosil (Degussa) type, cellulose
acetobutyrates of CAB (Eastman Kodak) type, polysaccharides and
cellulose derivatives of ethylcellulose and carboxymethylcellulose
(Hercules) type, montmorillonites of Kronos (NL Chemicals) type,
;
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vinyl and acrylic polymers and copolymers of VAGH (Union Carbide)
type.
Additives which induce substantial surface tension differences are
for example silicone oils of Baysilone A (Bayer) type,
methylpolysiloxanes of Tego Wet (Goldschmidt) type, acrylic polyrners
of Madaflow (Monsanto) type, fluoroderivatives of F'.C. (3 Emme)
type, oxyethylated surfactants of Etilon (Henkel) type, etc.
The required substantial difference in specific gravity can be
induced by adding suitable fillers to one of the coatings. Even a
different quantity of different pigments in the coatings can result
in a specific gravity difference such as to prevent mutual diffusion
of the coatings.
In addition to the already stated decorative effects of high
aesthetic merit, the advantages of the process of the invention
compared with processes of the known art are the obtaining of a
surface with chromatic structures by the application of a smaller
- number of coats, a higher yield and a faster coating cycle as only
one drying stage is required instead of two or more, with consequent
productivity increase; the possibility of embellishing supports made
of common material such as fibre or chipboard panels of waste wooden
material; and the possibility of personalizing decorative effects by
setting selected applicational parameters.
The coating systems of the invention consist of combina~ions of
coatings, each chosen from: polyurethane coatings comprising two
components (to be mixed together at the moment of use), coatings
based on binders with ethylenic unsaturations, physically driable
single-component coatings and coatings in the form of aqueous
2~3~3r~8
solutions, dispersions or emulsions.
As stated, the constituent coatings of each coating system can be
either of different type and thus incompatible (such a solvent-based
coating and a water-based coating) or of the same type. In this
latter case they must contain additives which induce a substantial
difference between the coatings in terms of their surface tension
and/or density and/or viscosity, to produce the interactions
necessary to prevent diffusion of one coating into another.
In two-component polyurethane coatings, the hydroxyl component has a
dry residue of between 20 and 80~ and consists of a solution of
resins with mobile hydrogens such as saturated polyester, polyol,
saturated acrylic and medium-short oil alkyd resins, hydroxylated
vinyl polymers, cellulose derivatives etc., dissolved in organic
solvents chosen from ethyl, butyl, isobutyl, methoxypropyl or
ethoxypropyl acetates, ketones such as methylethylketone, acetone,
cyclohexanone, methylisobutylketone, and aromatic solvents such as
toluene and xylenes. Organic and inorganic pigments of various type
and colour such as titanium dioxide, carbon black, phthalocyanine,
iron oxides etc. or soluble colorants and dyes can be added to these
solutions, as, if required, fillers such as calcium carbonate,
kaolin, silica, talc, zinc stearate, waxes etc., and surface
additives such as low molecular weight silicone oils, acrylic
polymers, surfactants etc.
The isocyanic component of said two-component polyurethane coatings
consists of solutions of polyisocyanates, isocyanic oligomers and
prepolymers, with dry residues between 10 and 95~, dissolved in
mixtures of anhydrous solvents such as acetates, ketones, aromatics
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and glycolether acetates similar to those described for the hydroxyl
component.
The coatings based on binders with ethylenic unsaturations, in which
the filming process takes place by radical reactions activated by
redox systems and/or by U.V-visible radiation have a dry residue of
between 30 and 95% and consist of unsaturated polyester, polyester
acrylate, epoxyacrylate, urethaneacrylate, acrylic, vinylic or
siliconacrylate resins; reactive unsaturated monomers of various
kinds such as styrene, hexanedioldiacrylate, TPGDA, TMPDA~ N-
vinylpyrrolidone, vinylacetate, trimethylolpropane-diallylether etc.
with possible addition of organic solvents chosen from those
indicated heretofore for the two-component polyurethane coatings.
Also present are pigments, fillers and surface additives similar to
those indicated heretofore for the polyurethane resins; and
photoinitiators containing the benzoyl group, which may be
substituted; accelerators formed from derivatives or organic salts
of transition metals such as cobalt, chromium, manganese etc.
If the filming process is activated by redox systems possibly
associated with U.V.-visible radiation, organic peroxides such as
cyclohexanoneperoxide, methylethylketoneperoxide, benzoylperoxide,
acetylacetoneperoxide, cumenehydroperoxide, peresters etc. are added
at the moment of use. Alternatively, instead of being added to the
coatings in question, said peroxides can be dissolved in a solution
of nitrocellulose polymer to be spread over the surface to be coated
before the constituent coatings of the coating system according to
the invention are applied (either simultaneously or in quick
succession).
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The physically driable single-component coatings have a dry residue
of between 5 and 70% and consist of vinyl, acrylic, polyurethane,
nitrocellulose, polyvinylbutyral etc. polymers, dissolved in organic
solvents such as ketones, acetates, aromatics, alcohols,
glycolether esters; they can also contain pigments, fillers and
surface additives similar to those defined initially for the two-
component polyurethane coatings.
The coatings f'ormed from aqueous solutions, dispersions or emulsion.s
have a dry residue of between 10 and 80% and consist of acrylic,
acrylourethane, vinyl etc. resins dissolved, emulsified or dispersed
in water, and in addition to pigments, fillers and surface
additives already def'ined for the other coatings, they can contain
small quantities of plasticizer and/or coalescent agents. The
filming process for said coatings, which occurs by evaparation of'
the water, can be supplemented by reactions on the carboxyl and/or
hydroxyl functions present by particular cross-linking agents, in
accordance with known methods.
The constituent coatings of the coating systems according to the
invention are applied either simultaneously or in quick succession,
within 1 to 5 seconds, using for example curtain coaters with two
heads positioned next to each other or at a determined distance
apart, or double feed sprayers with their nozzles positioned next to
each other or at a determined distance apart.
A particular apparatus suitable for the purpose is described in a
patent application filed by the applicant simultaneously with the
present application. This apparatus, which according to the effect
to be obtained can be positioned next to a normal curtain coater
2~3337~
head or at a determined distance upstream or downstream from it,
which we have called "mechanical brush", is provided with no~les
which al]ow controlled delivery of the coating either
discontinuously, in intermittent or droplet form, or as a continuous
flow, both methods being adjustable in terms of intensity and
frequency.
The essential elements of this apparatus are shown in Figures 1 to
3, Figure 1 is a view f'rom the top of part of the tank containing
the coating product; Figure 2 is a section on the line A-A and
Figure 3 is a section on the line B-B.
The apparatus comprises: a tank 1 of parallelepiped shape for
containing the coating product and housing in threaded seats in its
base various delivery heads 2 on which dispensing rods 3 act to
distribute the coating over the surface to be coated. The
dispensing rods are operated by rockers and a camshaft 4 driven by
a variable speed motor.
The delivery machine can be incorporated into an independent unit or
be positioned next to, in front of or behind the head of a
conventional curtain coater.
Varying the speed of rotation of the camshaft varies the time
between the opening periods of each delivery head.
As the speed of advancement of the material to be coated and the
camshaft r.p.m. are interdependent in terms of obtaining droplets at
- a constant rate, it follows that a wide range of droplet rates can
be obtained by varying the speed of advancement of the material to
be coated and/or the camshaft r.p.m.
The position of the cams on the camshaft can be adjusted at will to
2~33~7~
vary the rate of droplet delivery by one delivery head compared with
the others.
A special camshaft is used to obtain intermittent lines. Such
intermittent Lines can also be adjusted in terms of line length,
width and gap length.
A "continuous line delivery device" can be mounted on the upper
heads of the dispensing rods to halt the camshaft and so obtain
continuous delivery by the delivery heads. Adjustment is again
possible in this case to obtain thicker or thinner lines.
Further details of this apparatus are available from the industrial
invention patent application filed by the applicant simultaneously
with the present application.
This apparatus has proved particularly suitable for implementing
the process of the invention in that with normal known coating
application systems (sprayers, rollers, single or multi-head
curtain coaters) the possibility for creating variable decorative
effects is limited because a continuous film is always obtained.
In contrast the "mechanical brush" apparatus enables the coating to
be delivered in various rows of droplets, various rows of
continuous lines or various rows of intermittent lines, or
combinations of these, and the dimensions and arrangement of the
droplets and lines can be modified to obtain asymmetric and fantasy
patterns and shapes which are always reproducible.
The following non-limiting examples are given to better illustrate
the invention.
EXAMPLE 1
The coating system consiscs of a green unsaturated polyester coating
~033~78
and a grey coating of physically driable type.
The unsaturated polyester coating has the following percentage
formulation:
un.saturated polyester resin (Roskydal 500A) 71
5 styrene monomer 26.5
green pigment (C.I. Green 7) 1.0
photoinitiator (phosphine oxide derivative) 0.8
cobalt octanoate 0.3
surface additive (Efka 83) 0.2
10 antiblister additive (Efka 720) 0.2
The coating should have a viscosity of about 30-35 seconds (Ford cup
4. ASTM-1800-82 method). If necessary, this value is attained by
adding ethyl acetate.
The physically driable single component coating has the following
percentage formulation:
nitrocellulose polymer (Sipe Nobel) 16.0
saturated polyester resin (Novater 8583)8.6
titanium dioxide 5.0
carbon black 0.4
20 methylethylketone 22.0
isobutyl acetate 20.0
propyleneglycolmethyletheracetate (PMA)12.0
xylene 13-7
dibutylphthalate 2.0
25 surface additive (Efka 80) 0.3
The viscosity should be 15-20 seconds (Ford cup 4). If necessary,
this value is attained by adding ethyl acetate.
~ ~ ?~ 3 3 7 ~
g/m of a solution containing 15X of methylethylketone peroxide
and 8% of a nitrocellulose polymer of Hacolor (Hagedorn) type
dissolved in ethylacetate are applied by roller to fibre panels
treated with melamine paper.
They are heated to 45-50 C for 50 seconds by hot air circulation
after which the green polyester coating is applied by a curtain
coater in a quantity of about 120 g/m2.
After a second, using the mechanical brush of Figures 1 to 3, the
grey single-component coating is applied by dripping, in a quantity
oP about 35 g/m2.
The thus treated panels are subjected to the following drying cycle:
- 15 minutes in an oven at L~5_50 C by hot air circulation
- 15 minutes of U.V. irradiation by high power lamps (100 W/cm)
- 60 minutes at ambient temperature.
A glossy film properly hardened and adhering to the support is
obtained, of green colour with grey relief spots the dimensions and
fr~equency of which depend on the state of adjustment of the
mechanical brush.
The quality decorative effect obtained is properly reproducible.
EXAMPLE 2
The coating system is the same as described in Example 1, with only
the conditions of application with the mechanical brush and the
drying cycle being varied.
g/m of a solution containing 15% of methylethylketone peroxide
and 8% of a nitrocellulose polymer of Hacolor (Hagedorn) type
dissolved in ethylacetate are applied by roller to fibre panels
treated with melamine paper.
2~33~7~
They are heated to 45-50 C for about 60 seconds by hot air
circulation after which the green unsaturated polyester coating is
applied by a curtain coater in a quantity of about 120 g/m2.
Two seconds later, using the mechanical brush, the grey single-
component is applied in the form of continuous lines in a quantity
of about 60 g/m2.
The thus treated panels are subjected to the following drying cycle:
- 20 minutes in an oven at 40-50 C by hot air circulation
- 15 minutes of U.V. irradiation by high power lamps (100 W/cm)
- 70 minutes at ambient temperature,
A g]ossy film properly polymerized and adhering to the support is
obtained, of green colour with bas-relief lines the dimensions and
distance apart of which depend on the state of adjustment of the
mechanical brush.
The decorative effect is properly reproducible.
EXAMPLE 3
The coating system consists of two two-component polyurethane
coatings.
The first blue polyurethane coating is prepared by mixing together
at the moment of use 1 part of component A and 1 part of component
B. The two components have the following percentage formulation:
COMPONENT A
saturated polyester resin (Novater 8534) 21.0
saturated polyester resin (Resial 1113) 38-5
25 methylethylketone 16.5
isobutyl acetate 7.3
xylene 7-7
2033~8
12
methoxypropylacetate 3.8
carbon black 0.1
blue pigment (C.I. Pigment Blue 15) 3.5
titanium dioxide 1.5
5 surface additive 0.1
COMPONENT B
isocyanic polymer (Desmodur L) 22.0
isocyanic oligomer (Desmodur IL) 28.0
butyl acetate 11.0
10 methylethylketone 31.0
methoxypropylacetate 8.0
The coating obtained by mixing the two components should have a
viscosity of 15-20 seconds (Ford cup 4). If necessary, this value
is attained by adding ethylacetate.
The second yellow polyurethane coating is prepared by mixing
together at the moment of use 2 parts of the following component A
and 1 part of the following component B. These two components have
the following percentage formulation:
COMPONENT A
20 alkyd resin (Rexin LT 870) 27.0
alkyd resin (Rexin CM 65) 55.o
xylene 2.5
methylethylketone 2.9
yellow pigment (C.I. Pigment Yel]ow 3)8.o
25 antiblister additive 0.2
surface additive 0.2
U.V. adsorber 0.2
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methoxypropylacetate 4.0
COMPONENT ~
isocyanic prepolymer (Desmodur N 3390) 12.0
isocyanic oligomer (Desmodur IL) 36.o
5 butyl acetate 20.0
ethyl acetate 25.0
methoxypropylacetate 7.0
The coating obtained by mixing the two components should have a
viscosity of 25-30 seconds (Ford cup 4). If necessary, this value
is attained by adding ethylacetate.
Using the mechanical brush, the first blue polyurethane coating is
applied to filler-treated chipboard panels as a rapid series of
droplets in a quantity of about 55 g/m . This is immediately
followed, two seconds later, by application of the yellow
polyurethane coating by a curtain coater in a quantity of about 110
g/2.
The thus prepared panels are subjected to the following drying
cycle:
- 5 minutes at ambient temperature with air changes
- 70 minutes in an oven at 45-50 C with hot air circulation.
A properly polymerized adherent film is obtained, with its surface
in the form of small arched regions surrounding large blue openings.
The effect is properly reproducible.
EXAMPLE 4
The coating system consists of the products described in Example
3, but the yellow polyurethane coating has a viscosity of 10-15
seconds (Ford cup 4): it is now applied with two airbrushes.
2~3~P~8
14
The two coatings are applied simultaneously to filler-treated
chipboard panels1 the blue one in a ~uantity of about 110 g/m , the
yellow one in a quaneity of 120 g/m2.
The thus treated panels are subjectecl to the following drying cycle:
- 5 minutes at ambient temperature with air changes
- 70 minutes in an oven at 45-50 C with hot air circulation.
A properly hardened film adhering to its support is obtained, with a
glossy surface having relief graining of irregular design with
colours ranging from yellow to blue, and with a considerable green
component.
EXAMPLE 5
The coating system consists of a red physically driable coating and
a black unsaturated polyester coating.
The physically driable coating has the following percentage
15 formulation:
alkyd resin (Novater 8583) 10.0
vinyl chloride-vinyl acetate copolymer (VAGH~ 15.0
red pigment (C.I. Pigment Red 112) 5.0
ethyl acetate 15.0
20 toluene 20.0
methylethylketone 19.90
butyl acetate 15.0
surface additive 0.1
The viscosity should be 15-25 seconds (Ford cup 4). If necessary,
this value is attained by adding ethyl acetate.
The unsaturated polyester coating has the following percentage
formulation:
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unsaturated polyester resin (Roskydal 300) 47.30
styrene 15.5
nitrocellulose polymer (Sipe Nobel) 2.0
carbon black 0.2
5 photoinitiator 0.8
ethyl acetate 12.2
cobalt octanoate 0. 3
isobutyl acetate 8.5
toluene 10.9
10 surface additive 0.2
antiblister additive 0.1
The viscosity should be 25-30 seconds (Ford cup 4). If necessary,
this value is attained by adding ethyl acetate.
g/m oP a solution containing 15% of acetylacetone peroxide and
10% of a nitrocellulose polymer of Norma 34E (Sipe Nobel) type
dissolved in ethylacetate are applied by roller to fibre laminate
panels.
They are heated to 45-50 C for 65 seconds by hot air circulation,
after which about 20 g/m of the red coating are applied by slow
dripping using the mechanical brush, followed, three seconds later,
by about 1?0 g/m of the black unsaturated polyester coating using
a curtain coater.
The thus coated panels are then subjected to the following drying
cycle:
- 10 minutes at 40-50 c by hot air circulation
- 15 minutes of U.V. irradiation by high power lamps (80-120 W/cm)
- 45 minutes at ambient temperature.
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16
A film properly polymerized and adhering to the support is obtained,
having a black glossy surface with opaque red spots in bas-relief.
The decorative effect can be reproduced by keeping all operating
conditions unaltered.
EXAMPLE 6
The coating system is the same as in Example 5, whereas the
application and drying cycles are varied.
g/m2 of a solution containing 15% of acetylacetone peroxide and
10% of a nitrocellulose polymer dissolved in ethylacetate are
applied to fibre laminated panels.
They are heated to 45-50 C for 65 seconds by hot air circulation,
after which about 110 g/m of the red coating are applied by curtain
coater, followed by abou-t 40 g/m of the black unsaturated polyester
coating by rapid dripping using the mechanical brush.
The thus coated panels are then subjected to the following drying
cycle:
- 15 minutes at 40-45 C by hot air circulation
- 15 minutes of U.V. irradiation by high power lamps (100 W/cm)
- 70 minutes at ambient temperature.
A glossy film properly polymerized and adhering to the support is
obtained, having a red satin-like surface with tangential glossy
black relief spots. The effect is properly reproducible.
EXAMPLE 7
The coating consists of a two-component black polyurethane coating
and a coating in the form of a white aqueous dispersion.
The polyurethane coating is prepared by mixing together at thc
moment of use two parts of component A and one part of component B.
~ Q ~ 7 ~
17
The two components have the following percentage composition:
COMPONENT A
saturated polyester resin (Alftalat VAM 9905) 42.0
saturated polyester resin (Novater 8583) 18.0
5 carbon black z.O
nitrocellulose polymer (Norma E Sipe Nobel) o.75
ethyl acetate 5.0
isobutyl acetate 10.0
methoxypropylacetate 3.5
lO methylethylketone 7.7
xylene 9.0
paraffln wax 1.0
opacifying additive 0. 5
antiblister additive 0.2
15 surface additive o. 35
COMPONENT B
isocyanic polymer (Desmodur N 3390) 9.o
isocyanic polymer (Desmodur IL) 30~0
ethyl acetate 21.0
- 20 isobutyl acetate 35.0
~; methoxypropylacetate 5.0
The polyurethane coating obtained by mixing the two components
should have a viscosity of about 25-35 seconds (Ford CUp 4). If
necessary, this value is attained by adding ethylacetate.
The coating in aqueous dispersion form has the following percentage
composition:
urethane resin (Neorez R 961) 22.60
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18
acrylic resin (Neocryl XK-54) 41.8
titanium dioxide 12.0
opacifying agent SW OP 6002 5.0
anti-foaming agent (Dehydran 1293) 1.0
5 cross-linking agent (W 936) 10.0
surface additive 1.0
polyethylene wax (Aquacer) 6.6
The viscosity should be 25-35 seconds (Ford cup 4). If necessary,
this value is attained by adding water.
The black polyurethane coating is applied in a quantity of 60 g/m
in the form of thin continuous lines with the mechanical brush to
chipboard panels treated with melamine paper, and two seconds
later the water coating is applied in a quantity of 90 g/m by
curtain coater.
Considerable interaction between the two coatings is noted, with the
-formation of the decorative effect.
The coated panels are then dried at 45-50 C for 90 minutes by hot
air circulation.
In this manner a properly hardened satin-like film is obtained
having a black surface with regular white lines in relief, with grey
edges. The decorative effect is reproducible.
EXAMPLE 8
The coating system comprises the coatings of Example 7.
Using a two-headed curtain coater, the black polyurethane coating
in a quantity of 100 g/m2 and contemporaneously the water
coating in a quantity of 80 g/m are applied to filler-treated
chipboard panels.
2~3337~
19
The panels are then dried for 90 minutes at 45-50 c by hot air
circulation.
In this manner a hard film adhering to its support is obtained,
having a black opaque surface with whlte reliefs of irregular
shape.
EXAMPLE 9
The coating system consists of a white coating in aqueous dispersion
form and a blue physically driable coating.
The aqueous dispersion coating has the following percentage
c0mpOSition
urethane resin (Neorez R 961) 17.50
acrylic resin (Neocryl XK-54) 48.50
mineral filler (calcium carbonate) 4.o
mineral filler (talc) 1.0
15 titanium dioxide 12.0
cross-linking agent 10.0
anti-foaming agent (Dehydran 1293) 1.0
surface additive 1.0
polyethylene wax (Aquacer) 5.0
The viscosity of the coating should be 15-25 seconds (Ford cup 4).
If necessary, this value is attained by adding water.
The physically driable coating has the following percentage
composition:
cellulose acetobutyrate 13.5
25 saturated polyester resin (Novater 8583)13.0
blue pigment (C.I. Pigment blue 16) 5.0
ethyl acetate 16.0
20~3~7~
methylethylketone 13.0
butyl acetate 15.0
toluene 15.0
methoxypropylacetate 7.3
S surface additive 0.2
The viscosity should be 15-25 seconds (Ford cup 4). If necessary,
this value is attained by adding ethyl acetate.
The aqueous coating is applied in a quantity of about 25 g/m by
slow dripping with the mechanical brush to chipboard panels treated
with melamine paper, followed, two seconds later, by application oP
the blue single component in a quantity of 100 g/m by curtain
coater. The coated panels are dried for 90 minutes at 45-50 C in an
oven with hot air circulation.
In this manner a hard film adhering to the support is obtained,
having a blue satin-like surface with light blue round spots in bas
relief. The effect is properly controllable and reproducible.
EXAMPLE 10
The system is the same as in Example 9.
The aqueous coating is applied in a quantity of 100 g/m by curtain
~20 coater to filler-filled fibre panels, followed, three seconds
later, by application of the physically driable coating in a
quantity of 30 g/m by slow dripping with the mechanical brush.
The panels are then dried for 90 minutes at 45-50 C by hot air
circulation.
-25 In this manner a hard film adhering to the support is obtained,
having a white opaque surface with regular blue spots having a light
blue halo. The decorative effect is regular and properly
2~33~7~
repeatable.
EXAMPLE 11
The coating system comprises two aqueous coatings.
The first coating has the following percentage composition:
5 urethane resin (Neorez R 961) 22.60
acrylic resin (Neocryl XK-54) 4l.8
anti-foaming agent (Dehydran 1293) 1.0
titanium dioxide 12.0
opacifying agent (SW OP 6002) 5,0
lO cross-linking agent 10.0
surface additive 1.0
polyethylene wax (Aquacer) 6.6
The viscosity of the coating prepared in this manner is adjusted if
necessary to 20-25 seconds (Ford 4 cup) by adding water.
The second coating has the following percentage composition:
urethane resin (Neorez R 961) 27.0
carboxylated acrylic resin (Neocryl XK-54) 50. o
mica particles (Mearlin Super White) 0.5
blue pigrnent (C.I. Pigment Blue 15) 1.5
20 opacifying silica 1.0
polyethylene wax 3 5
anti-foarning agent (Dehydran 1293) 1.5
water 15.0
The coating viscosity should be 30-35 seconds (Ford cup 4). If
necessary, this value is attained by adding water.
The first coating is applied in a quantity of about 130 g/m by
curtain coater to filler-filled fibre panels, followed, three
~333~
seconds later, by application of the second coating in a quantity of
25 g/m2 by slow dripping with the mechanical brush.
The thus treated panels are then dried for 80 minutes at 45-50 C in
an oven with hot air circulation.
In this manner a hard film adhering to the support is obtained,
having a white surface with light blue shaded nucleate drops (in the
form of cells) having a blue core with pearly reflections.
EXAMPLE 12
The coating system consists of the two aqueous coatings described in
Example 11.
The first white coating is applied in a quantity of about 130 g/m
by curtain coater to MDF panels treated with melamine paper,
followed, one second later, by application of the second blue
coating in a quantity of about 40 g/m by slow dripping with the
mechanical brush.
The coated panels are dried at 50 C in an oven with hot air
circulation for 80 minutes.
A hard film adhering to the support is obtained, having a white
surface with large blue pearlescent cores in relief surrounded by
blue haloes also in relief.
EXAMPLE 13
The coating system consists of a green unsaturated polyester
coating, a grey physically driable coating and a white coating in
aqueous dispersion form.
The unsaturated polyester coating has the following percentage
formulation:
unsaturated polyester resin (Roskydal 500A) 76.0
2 ~ 7 8
23
styrene monomer 21.5
green pigment (C.I. Green 7) 1.5
cobalt octanoate 0.5
surface additive (Efka ~3) o.3
5 antiblister additive (Eflca 720) 0.2
The coating should have a viscosity of about 30-35 seconds (Ford cup
4). If necessary, this value is attained by adding ethyl acetate.
The grey physically driable coating has the following percentage
formulation:
lO nitrocellulose polymer (Norma 24 E Sipe Nobel) 16.0
saturated polyester resin (Novater 8583) 8.6
titanium dioxide 5.o
carbon black o.4
methylethylketone 22.0
15 isobutyl acetate 20.0
propyleneglycolmethylether acetate (PMA) 12.0
xylene 13.7
dibutylphthalate 2.0
surface additive (Efka 80) 0.3
The viscosity should be 15-20 seconds (Ford cup 4). If necessary,
this value is attained by adding ethyl acetate.
The white coating in aqueous dispersion form has the following
percentage formulation:
urethane resin (Neorez R 961) 23.0
25 carboxylated acrylic resin (Neocryl XK-54) 41.4
anti-foaming agent (Dehydran 1293) l.o
titanium dioxide 12.0
2(3~37~
2~
opacifying agent (SW OP 6002) 5.o
cross-linking agent (W 936) 10.0
surface additive 1.0
polyethylene wax (Aquacer) 6.6
The viscosity of the coating prepared in this manner is adjusted if
necessary to 20-25 seconds (Ford 4 cup) by adding water.
g/m of a solution containing 15% of cyclohexanone peroxi.de and
10% of a nitrocellulose polymer of Hacolor (Hagedorn) type dissolved
in ethylacetate are applied by roller to filler-treated chipboard
panels.
They are heated to L~5_50 C for 50 seconds by hot air circulation
after which the green unsaturated polyester coating is applied with
the first head of the curtain coater in a quantity of about 110
g/m ; one second later, the grey single-component coating is
applied by dripping using the mechanical brush, in a quantity of 20
g/m and contemporaneously the white coating in aqueous dispersion
form is applied with the second head of the curtain coater in a
quantity of 70 g/m .
The thus treated panels are dried in the following manner:
5 minutes at ambient temperature with air circulation (flash period)
70 minutes in an oven at 45-50 C with hot air circulation.
In this manner a properly hardened film adhering to the support is
obtained, of green colour with grey and white spots in relief. The
effect is reproducible.
