Decorative panel

A base coated substrate carries a pattern defined by a silicone-containing printing ink. A silicone-containing top coat covers the inked substrate, the top coat being disturbed by the repulsion forces of the ink's silicone at locations adjacent the edges of the patterns thereby producing a three-dimensional effect in an otherwise smooth top coat surface.

The present invention relates to a decorative panel particularly suited for 
such uses as wall and ceiling coverings, furniture, etc. In fabricating 
such a panel, it is desirable to produce a surface which is non-uniform so 
as to provide a three-dimensional effect. 
Attempts have been made in the past to form a panel having a textured 
surface by applying to a substrate a silicone-containing ink in a pattern 
and covering the inked substrate with a top coating. The silicone repels 
the top coating at the edges of the ink-top coat interface to produce an 
uneven surface. Such prior efforts are disclosed, for example, in U.S. 
Pat. No. 3,811,915 which issued on May 21, 1974 in the names of Harry 
Bunell and Robert C. Millen, Jr., and in Canadian Pat. No. 981,124 which 
has granted to John C. Barker and Ivan P. McLaughlin on Jan. 6. 1976. 
However, an important shortcoming exists in the previously known products. 
More particularly, using the techniques described in the aforesaid 
patents, when a given segment of ink covers a substantial area for the 
purpose of producing, for example, a geometric figure on the finished 
panel, the application of the top coating results in the figure having a 
plurality of separate "islands" of top coating within the confines of the 
area defined by the ink or alternatively a series of "fisheyes" or cells 
of the top coating within this area. The latter result can be referred to 
as a "hammered" effect. While such configurations have interesting and 
attractive appearances, it is impossible to accurately duplicate them in 
subsequent panels. Thus, when a plurality of panels so fabricated are used 
to cover a wall, the randomly produced effects in the several panels 
produce an overall appearance which is generally unacceptable. 
The problem just described is recognized in Canadian Pat. No. 981,124 where 
it is stated that for best results, the inked pattern should define lines 
of 1/1 6 to 3/16 thickness rather than surface areas. 
Another shortcoming of products of the type disclosed in the aforesaid 
patents is that as the upper limit of silicone in the printing ink is 
reached (the upper limits being stated as 3% in U.S. Pat. No. 3,811,915 
and 5% in Canadian Pat. No. 981,124), the displacement of the top coat 
away from the edges of the printing ink increases causing a substantial 
build-up of top coat material in an irregular manner. This condition 
detracts from the appearance of the product. 
A still further aesthetic problem of prior art products is that when a 
material such as polyester is used in the top coat (as is disclosed in 
each of the aforesaid patents), the natural characteristic of the material 
is to produce an uneven surface. 
SUMMARY OF THE INVENTION 
The present invention constitutes an improvement over the prior art by 
providing for a panel construction having a three-dimensional effect on 
its surface while also allowing large surface areas to be printed and 
covered with a top coating of uniform thickness. This is accomplished by 
providing respectively both the pattern-defining ink and the top coating 
with silicone components, whereby at the peripheries of the inked areas 
there is a flow of the top coat so as to produce a sharply defined 
depression-elevation phenomenon which gives the product its 
three-dimensional effect, while over the printing ink areas and over the 
unprinted areas not encompassed by depressions and elevations the top coat 
is rendered smooth. The resultant product is one which can be repeatedly 
reproduced with great accuracy thereby making the product suitable for 
mass production.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1 and 2 of the drawings, the problem which the present 
invention solves will first be explained. 
If a substrate 10 is covered with a base coat 11 and then with a pattern of 
silicone-containing printing ink 12 in accordance with the teachings of 
the aforesaid U.S. Pat. No. 3,811,915 and Canadian Pat. No. 981,124, and 
should areas defined by the printing ink 12 be substantial, the 
application of a conventional top coat over the exposed surface of the 
assembley produces a series of "islands" 14 (or sometimes a series of 
"fisheyes" or cells) of top coat material separated by voids 16 which 
expose the printing ink. This creates an appearance which is not 
reproducible with continuous accuracy. 
The silicone in ink 12 also repels the top coat adjacent to the printed 
pattern to cause a buildup of top coat material designated as 17. With the 
ink's silicone content in the general range of 3 - 5%, the buildup of the 
top coat is substantial and assures an irregular outline as can be seen in 
FIG. 1. This contributes to an unacceptable product appearance, 
particularly when the top coat is pigmented with colors which are not 
muted. As shown in FIG. 2, the remaining surface of top coat over the 
unprinted area often is uneven, particularly if a polyester is used as a 
component of the top coat. Also in accordance with U.S. Pat. No. 3,811,915 
and Canadian Pat. No. 981,124 the surface of the top coat over the 
unprinted areas is higher than over the printed areas. 
In accordance with the present invention, the problems just discussed are 
overcome as now will be described with reference to FIG. 3. 
A cleaned substrate 18, typically a material such as hardboard, paper, 
cardboard, particle board, hardwood, cement asbestos, aluminum, etc., 
receives a plurality of successive coatings. In the case of certain of 
these materials (e.g., plywood, hardwood and particle board) the first of 
these coatings is a filler or sealer (not shown). Such a coating, if 
employed, is accomplished with conventional materials and techniques so 
well known in the art that it is unnecessary to list them at this time, 
particularly since they form no part of the present invention. 
A pigmented base coat 20 then is applied to the substrate by conventional 
techniques such as roller or curtain coating. After drying of the base 
coat, a silicone-containing printing ink 22 is selectively disposed on the 
base coat in a pattern established by such typical processes as silk 
screen, offset, rotogravure, flexography, brush (air or hand), airbrush, 
etc. 
Following a drying step which is employed to drive off solvents (and in the 
case of a seccative ink, to completely dry the ink), a top coat 24 is used 
to cover the ink 22 and the portions of base coat 20 left exposed by the 
ink. The top coat is applied by conventional means such as rollers, 
spraying equipment, brushes, electrostatics, etc. Thereafter, the product 
is exposed to a step in which any remaining solvents are driven off, and 
the product is dried. This step can be performed by open air, hot 
circulated air, air jets, infra-red heaters, electron beams, ultraviolet, 
electric or gas heaters, or combinations of these conventional techniques. 
As will be explained hereinafter, the top coat 24 also contains a silicone. 
Accordingly, the effect of the silicones in ink 22 and top coat 24 is to 
produce depressions 26 at the ink-top coat interface adjacent the edges of 
the ink and elevations 28 immediately outwardly of the depression 26. The 
location of these depressions and elevations is controlled by the top coat 
silicones. No surface disturbance is created over the printed areas, 
notwithstanding their size, and therefore, a smooth top coat surface is 
left in these areas, this surface being at a level between those of the 
peaks of the depressions 26 and the elevations 28. The level of top coat 
24 over the printed areas is substantially the same as that of the 
remaining top coat covering the previously exposed areas of base coat 20. 
The latter also has a smooth surface due to the silicone in the top coat. 
As a result of the control achieved according to the invention, the pattern 
can be precisely repeated in manufacturing subsequent panels. Thus, 
uniform panels can be made on a continuous basis. 
The results of the invention having been described, details of materials 
which may be employed in fabricating the improved product now will be set 
forth. 
Base Coat 
A number of conventional base coat materials are suitable for use in 
practicing the present invention. One such formulation which has been 
employed is as follows with proportions being indicated as percentage by 
weight. 
______________________________________ 
Range Preferred Amount 
______________________________________ 
titanium dioxide 
25 - 33 % 30 % 
calcium carbonate 
20 - 25 % 22 % 
lecithin 1.3 - 1.7 % 1.5 % 
alkyd resin 15 - 20 % 16.1 % 
(non-drying) 
aromatic solvent 
7 - 10 % 8 % 
(with high boiling point) 
xylene 4 - 6 % 4.4 % 
melamine resin 
10 - 15 % 12.5 % 
butyl alcohol 2.5 - 5 % 3.0 % 
glycol butyl ether, 
2 - 4 % 2.5 % 
2-butoxyethanol 
______________________________________ 
The alkyd resin just listed is a reaction product of phthalic anhydride and 
glycerol modified with a short-oil (raw castor oil). The resin has a 
solids content of 50% in solution with a xylol solvent, KKK a 
Gardner-Holdt viscosity of N-P, a specific weight of 0.989-0.999 and an 
acid number of 8-13. 
The melamine resin is a reaction product of melamine, formaldehyde and 
butyl alcohol. The resin has a solids content of 58-62% in solution with 
xylol-butanol, KKK a Gardner-Holdt viscosity of S--V, a specific weight of 
1.02-1.04 and an acid number of 1 (max.). 
The high boiling point aromatic solvent is typically a material such as 
Esso's Solvesso 100 having a specific weight 70/60.degree. F of 0.8729, a 
flash point of 115.degree. F, an aromatics content of 99.2 (D-1319) and 
97.4 (D-875), a boiling range of 320.degree. F (initial point) to 
350.degree. F (final state) and a refraction index of 1.49988. 
Printing Ink Base 
A suitable base for a printing ink employed in carrying out the present 
invention includes: 
______________________________________ 
Range Preferred Amount 
______________________________________ 
isophorone 10 - 13 % 11.5 % 
COCH:C(CH.sub.3) 
CH.sub.2 C(CH.sub.3).sub.2 CH.sub.2 
glycol butyl ether, 
12 - 15 % 14.0 % 
2-butoxyethanol 
diacetone alcohol 
5 - 8 % 6.5 % 
hexylene glycol 
6 -9 % 9.8 % 
vinyl resin 4 - 6 % 4.2 % 
alkyd resin (same 
19.5 - 20 % 19.0 % 
as used in 
base coat) 
calcium carbonate 
1.8 - 2.5 % 2.1 % 
lecithin 0.8 - 1.3 % 1.0 % 
thickener agent 
18 - 24 % 22.0 % 
pigment 10 - 30 % 11.9 % 
(for a 
typical yellow) 
______________________________________ 
The vinyl resin is a vinyl chloride-vinyl acetate copolymer (91% PVC and 3% 
PVA, with the remainder being a hydroxyl calculated as vinyl alcohol). The 
resin has a specific weight of 1.39, a molecular weight of 23,100 and a 
glass transition temperature of 79.degree. C. 
The thickener agent typically has a formulation of: 
______________________________________ 
Range Preferred Amount 
______________________________________ 
xylene 75 - 83 % 
81.6 % 
Bentone 38 (a commercial 
9.5 - 11 % 
10.2 % 
product of NL Industries, Inc.) 
Anti-Terra U (a commercial 
8 - 10 % 8.2 % 
product of Byk-Mallinckrott) 
______________________________________ 
Bentone 38 is an organic derivative of montmorillonite clay having a 
density (gm/cm.sup.3) of 1.70. 
Anti-Terra U is an ester acid of high molecular weight over a base of 
polyaminamide salt. The composition has a specific weight 20/4.degree. C 
of 0.94, a pH of 6 - 8, an index of refraction of 1.490 and a flash point 
of approximately 23.degree. C (Abel-Persky). 
While the foregoing ink base formulation utilizes as a binder a combination 
of vinyl and alkyd resins, it also is possible to use just a vinyl or an 
alkyd resin as the binder. Alternatively, other binders which may be 
employed are nitrocellulose, chloridated rubber (C.sub.10 H.sub.11 
Cl.sub.7), an oil free polyester resin with nitrocellulose, or 
combinations of such binder materials. A suitable oil free polyester is 
the commercial product Polylite JC-643 by Reichhold Chemicals, Inc., a 
product of the reaction of a synthetic saturated fatty acid having a 
viscosity (Gardner) of Z.sub.1 - Z.sub.4, a solids content of 69 - 71% in 
solution with a xylol solvent, an acid number of 7 (max.), a hydroxyl 
number of 140 - 160 and a hydroxyl percentage of 4.24 - 4.84%. 
The ink base may employ a single pigment. Alternatively, differently 
pigmented ink base formulations may be utilized for different areas of the 
surface being coated so as to create various color effects. 
Silicone Additive to Printing Ink Base 
In order to obtain the desired three-dimensional effect discussed 
previously, a silicone material is added to the printing ink base in 
amounts of 5 - 20% by weight of the combination of the base and the 
silicone. Silicones which may be used in the printing ink include: 
di-methylsiloxane, 
polydi-methyl siloxane, 
phenyl methyl polysiloxane. 
A typical example of a di-methylsiloxane is the commercial product Dow 200 
which has a viscosity of 60,000 centistokes at 25.degree. C (ASTM D 445, 
Appendix C), a specific weight of 0.976 at 25.degree. C (ASTM D 1298), a 
flash point of 321.degree. F (ASTM D 92, open cup), an index of refraction 
of 1.4035 at 25.degree. C (ASTM D 1218) and a surface tension at 
25.degree. C of 21.5 dynes/cm. 
A representative example of a polydi-methyl siloxane is the commercial 
silicone fluid M 300,000 by Bayer which is a di-methyl polymer terminated 
in groups of trimethylsiloxane and having the formula: 
##STR1## 
This product has a viscosity of 300,000 centistrokes .+-. 10%, a specific 
weight D 20/4.degree. C of 0.96 - 0.97, a flash point above 350.degree. C 
and a refraction index of 1.405. 
An example of a phenyl methyl siloxane is Bayer's silicone fluid PL which 
has a viscosity of 210 .+-. 50 centipoises at 20.degree. C in a Hopper 
ball viscometer, a specific weight D 20/4.degree. C of 1.06 .+-. 0.02 and 
a surface tension of approximately 24 dynes/cm. 
Top Coat 
A composition suitable for use is: 
______________________________________ 
Range Preferred Amount 
______________________________________ 
polyester, wax free 
58 - 64 % 61.9 % 
cobalt - 6% metal 
0.7 - 0.8 % 0.74 % 
content 
silicone solution 
1 - 10 % 3.0 % 
styrene monomer 
9 - 15 % 11.3 % 
diacetone alcohol 
2 - 4 % 2.46 % 
thixotropic 18 - 23 % 20.6 % 
______________________________________ 
The wax free polyester is a reaction product of maleic anhydride, phthalic 
anhydride, propylene glycol and trimethylolpropane diallyl ether. When the 
resin is combined with a styrene monomer in a 65/35 ratio, the mixture has 
a viscosity at 25.degree. C of 500 - 1000 centipoises and an acid index of 
35 (max.). 
The thixotropic is formulated with a 98% content of the wax free polyester 
just described and a 2% content of a material commercially available as 
Degussa's Aerosil 200 (which has a silicium dioxide content of at least 
99.8% and less than 0.05% alumina). 
Binders other than the wax free polyester which may be used in the top coat 
formulation are alkyds, alkyd amines, acrylics, acrylic amines, epoxies, 
polyesters (non-saturated) with paraffin, vinyl lacquers, nitrocellulose 
lacquers, polyurethanes and oil free polyesters in combination with any of 
the foregoing materials. 
Silicones which are suitable for the top coat are those which are referred 
to in the art as "anti-silicones", i.e., they have the property, when 
brought in contact with a silicone-containing surface of allowing adhesion 
with the latter surface. Consequently, when such "anti-silicones" are used 
in a top coat applied over a silicone-containing printing ink, 
substantially no surface disturbance occurs in the top coat material and 
the coatings adhere to one another with a smooth surface occurring over 
the printed areas. 
The silicones used in the top coat also provide an additional advantage in 
improving the flow of the top coat in the unprinted areas of the panel 
beyond the depressions 26 and elevations 28 discussed with respect to FIG. 
3. 
Thus, the elimination of surface disturbances over the printed areas and 
the improved flow of the top coat over the unprinted areas result in a 
smooth, blemish free panel which has a three-dimensional effect adjacent 
the peripheries of the printed areas. 
Preferably the silicone used in the top coat has a viscosity less than 
approximately 1,000 centistokes. Typical silicone materials which may be 
included in the top coat are commercially available silicone oils, 
designated A and OL, produced by Bayer. 
Bayer Silicone Fluid A is a 100% polysiloxane having a specific weight D 
20/4.degree. C of 0.96 - 0.97, a viscosity at 20.degree. C of 5 - 20 
centipoises, a flash point of approximately 45.degree. C and a surface 
tension of approximately 20 dynes/cm. 
The Silicone Fluid OL by Bayer is an organofunctional silicone fluid having 
a specific weight D 20/4.degree. C of 1.035 .+-. 0.01, a viscosity of 600 
.+-. 100 centipoises at 20.degree. C in a Hoppler ball viscometer, a flash 
point as per DIN 51 758 (Persky -- Martins) of above 90.degree. C, and a 
surface tension of approximately 23 dynes/cm. 
Of course, in order to impart additional color effects to the product, 
pigments can be added to the top coat formulation in amounts up to 
approximately 10% by weight of the combination. The pigments may either be 
suspended in the top coat formulation or added thereto after being 
dissolved in an aniline. 
So as to permit curing of the materials following the application of the 
top coat, a suitable catalyst is added with the top coat binder to the top 
coat formulation. A typical catalyst appropriate for such use is benzoyl 
peroxide in a quantity of approximately 2 - 4%. 
The invention will be further illustrated but should not be limited by the 
examples to follow. In each case a hardboard substrate was provided with a 
base coat prepared according to the preferred formulation indicated above. 
Upon this base coat a pattern of printing ink was applied. The pattern 
included diverse configurations such as lines, dots and large surface 
areas. The base used for the printing ink was formulated in accordance 
with the preferred composition previously recited. A top coat was applied 
over the entire coated surface of the substrate. Deviations from the 
preferred top coat formulation included variations in the type of top coat 
binder utilized and in amounts of the silicone solution and the styrene 
monomer separately added to the top coat. 
EXAMPLE 1 
Silicone added to printing ink base: 
5% (Dow Corning 200) 
Silicone solution included in top coat: 
3% (Bayer Silicone Fluid A) 
Styrene monomer -- 11.3% 
Top coat binder -- polyester, wax free 
EXAMPLE 2 
Silicone added to printing ink base: 
10% (Bayer Silicone Fluid M 300,000) 
Silicone solution included in top coat: 
3% (Bayer Silicone Fluid A) 
Styrene monomer -- 11.3% 
Top coat binder -- polyester, wax free 
EXAMPLE 3 
Silicone added to printing ink base: 
20% (Bayer Silicone Fluid PL) 
Silicone solution included in top coat: 
3% (Bayer Silicone Fluid OL) 
Styrene monomer -- 11.3% 
Top coat binder -- polyester, wax free 
EXAMPLE 4 
Silicone added to printing ink base: 
5% (50/50 mixture of Bayer Silicone Fluid PL and M 300,000) 
Silicone solution included in top coat: 
3% (Bayer Silicone Fluid OL) 
Styrene monomer -- 11.3% 
Top coat binder -- polyester, wax free 
EXAMPLE 5 
Silicone added to printing ink base: 
6% (50/50 mixture of Bayer Silicone Fluid PL and Dow Corning 200) 
Silicone solution included in top coat: 
2.5% (Bayer Silicone Fluid A) 
Styrene monomer -- 11.8% 
Top coat binder -- polyester, wax free 
EXAMPLE 6 
Silicone added to printing ink base: 
8% (50/50 mixture of Bayer Silicone Fluid M 300,000 and Dow Corning 200) 
Silicone solution included in top coat: 
2.5% (Bayer Silicone Fluid A) 
Styrene monomer -- 11.8% 
Top coat binder -- polyester, wax free 
EXAMPLE 7 
Silicone added to printing ink base: 
20% (equal mixture of Bayer Silicone Fluids PL and M 300,000 and Dow 
Corning 200) 
Silicone solution included in top coat: 
2.5% (Bayer Silicone Fluid OL) 
Styrene monomer -- 11.8% 
Top coat binder -- polyester, wax free 
EXAMPLE 8 
Silicone added to printing ink base: 
5% (Dow Corning 200) 
Silicone Solution included in top coat: 
1% (Bayer Silicone Fluid A) 
Styrene monomer -- 13.3% 
Top coat binder -- alkyd melamine 
EXAMPLE 9 
Silicone added to printing ink base: 
5% (Dow Corning 200) 
Silicone solution included in top coat: 
10% (Bayer Silicone Fluid OL) 
Styrene monomer -- 4.3% 
Top coat binder -- polyester, wax free 
EXAMPLES 10 - 12 
Silicone added to printing ink base: 
Ex. 10 -- 8% (Dow Corning 200) 
Ex. 11 -- 12% (Dow Corning 200) 
Ex. 12 -- 18% (Dow Corning 200) 
Silicone solution included in top coat: 
2.5% (Bayer Silicone Fluid OL) 
Styrene monomer: 11.8% 
Top coat binder: polyester, wax free 
EXAMPLES 13 - 15 
Silicone added to printing ink base: 
Ex. 13 -- 8% (Dow Corning 200) 
Ex. 14 -- 12% (Dow Corning 200) 
Ex. 15 -- 18% (Dow Corning 200) 
Silicone solution included in top coat: 
3.5% (Bayer Silicone Fluid OL) 
Styrene monomer -- 10.8% 
Top coat binder: polyester, wax free 
EXAMPLES 16 - 18 
Silicone added to printing ink base: 
Ex. 16 -- 8% (Dow Corning 200) 
Ex. 17 -- 12% (Dow Corning 200) 
Ex. 18 -- 18% (Dow Corning 200) 
Silicone solution included in top coat: 
5.0% (Bayer Silicone Fluid OL) 
Styrene monomer -- 9.3% 
Top coat binder: polyester, wax free 
In each of the foregoing examples a product was achieved which had a solid, 
uninterrupted, smooth-surfaced top coat over the printed areas. This 
resulted from the combined effect of the silicones of the printing ink and 
the top coat. Instead of breaking into "islands" or a series of "fisheyes" 
or cells, the total amount of silicone at the interface of the top coat 
and the ink over the pattern (contributed to primarily by the printing ink 
composition) was sufficiently large to prevent a surface disturbance of 
the top coat. 
However, since the repulsion forces of the silicones used in the top coat 
are less than those of the printing ink silicone, the forces of the latter 
directed away from the printed patterns were able to overcome opposing 
forces of the top coat silicone so as to produce the depressions 26 and 
elevations 28 of FIG. 3 immediately adjacent the printed areas. The 
reaction forces of the top coat silicone were sufficient nevertheless to 
limit the extent of displacement of the top coat thereby preventing a 
large buildup of top coat material and sharply defining the depressions 26 
and elevations 28 to avoid irregularities of the type designated at 17 in 
FIG. 1. 
The silicone content of the top coat also prevented those remaining 
portions of the top coat over unprinted areas from curing with an 
irregular surface shown in FIG. 2. This was due to the flow characteristic 
supplied by this silicone. Consequently, except for the depressions 26 and 
elevations 28, the surfaces of the top coat were smooth and substantially 
level with respect to one another throughout the product.