Note: Descriptions are shown in the official language in which they were submitted.
39588
This application is a divisional application of
Canadian patent application No. 612,951 filed on September 25th,
1989.
WATER-REDUCIBLE COATING COMPOSITION
AND PROCESS OF USE THEREOF
The parent invention is directed to a method and
compositions used therewith for coating wood, metal or plastic
to render it capable of receiving wood-grain printing inks and
conventional wood stains, while also concealing joints and
other imperfections.
In the decorative uses of wood, there are many
applications in which visible joints in the wood are not
desired. For example, in the use of moldings along the edges
of doors, window frames, and the like, it is desirable to have
each edge constructed of a single length of wood. Moreover,
to have a decorative effect, the wood is often stained to a
desired color, such as walnut, rosewood, and the like, then
covered with a protective coating such as varnish or other
conventional clear coating. The use of single lengths of wood
is expensive and wasteful, since short lengths of scrap wood
are not reusable. There is no practical alternative to using
single lengths of wood for molding. Plastics or compounded
wood pulp products are usually not desirable since they either
do not have sufficient strength and durability or do not have
the pleasing wood grain surface texture. A piece ofplywood
would also be extremely expensive since one or more surfaces of
the molding would have to be veneered, making it much more
expensive than a solid piece of wood.
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The use of scrap pieces of wood joined together, such
as by finger joints, would be desirable. There has been
difficulty however, in treating joined pieces of wood to have
the appearance of a single piece of wood for decorative
purposes. One such method is described in commonly assigned
Patent No. 4,546,133, wherein specialized wood coating and ink
compositions are disclosed. The present invention provides an
improved method and coating for metal or plastic to impart
wood-like appearance, or for concealing joints in wood, while
still maintaining the appearance and texture of a single piece
of wood. The coating according to the present invention also
is capable of accepting conventional wood stains.
The present invention therefore seeks to provide
water-reducible compositions which are useful for coating metal
or plastic to impart a wood-like appearance, or for coating
wood to conceal joints, but which retain the grainy appearance
of the natural wood.
The present invention also seeks to provide novel
coatings for metal, plastic or wood which accept conventional
wood stains.
The invention will be apparent from the following
description and preferred embodiments.
The method of the parent application utilizes a base-
coat composition for covering plastic, metal, wood or a wood
product comprising a combination of resins, pigments, solvents,
and additives for suspension, dispersion, thickening, flowing
and defoaming. In the invention of this divisional application
a printing composition is also provided comprising resin,
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pigments, solvents, and anti-foaming and wetting agents.
The method according to the present invention
comprises the steps of applying a novel liquid basecoat onto
metal, plastic/ natural wood or a wood product, evaporating
volatile solvents to form a solid coating, and applying a
novel ink composition in a wood grain pattern onto the solid
coating.
The starting material for forming a coated product
may be any product having a plastic, metal or wood surface,
including strips, with or without joints, sheets, including
plywood and wood grain paper, or any other product derived
from wood or wood pulp, sawdust, and the like. Since a primary
purpose for the use of the compositions according to the present
invention is to provide a decorative surface, it is desirable,
but not necessary, that the starting material have a wood grain
texture, since that texture will be substantially retained after
the basecoat coating is applied.
Generally, the metal, plastic, wood or wood product
will be coated with a liquid basecoat composition then dried to
remove the volatile solvents. The drying is preferably
performed with heat in a conventional oven, but other
evaporative methods may be utilized. Then a grain ink formula-
tion may be applied in a pattern to simulate a wood grain using
a conventional roller having a wood grain pattern using the
inks described herein. Apparatus for performing these functions
are conventional and known in the art.
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The basecoat formulation according to the present
invention comprises the following components:
acrylic resins, styrene-maleic anhydride resins,
pigments and fillers, thickener, flow agents,
defoaming agents and solvents.
In general, the water-reducible basecoat, according
to the invention will contain the following:
% by volume
Water 20-30
10 Organic solvents 1-5
Styrene-maleic anhydride resins 0.5-3
Acrylic resins 45-~5
Pigments and inorganic fillers 10-20
organic thickener up to 1
15 Defoaming agents up to 3
Flow agents up to 5
Suspension agent up to 1
Nut shell flour 1-5
A particularly preferred basecoat composition useful
for coating wood contains the following (percentages
given by volume).
~ ~y volume
Water 23.50
Organic solvents 1.72
25 Styrene-maleic anhydride resins 0.8
Acrylic resins 51.10
Pigments and inorganic fillers 15.98
organic thickener 0.17
Defoaming agents 1.02
30 Flow agents 3 33
Suspension agent 0.18
Nut shell flour 2.20
In a preferred formulation, the acrylic resins and
styrene-maleic anhydride resins are the commercially
~5 available resins Joncryl 89 (Johnson & Johnson),
Rhoplex AC-~07 (~ohm & Haas), and SMA-1440 (Sartomer
Company).
Absorption pigments and inert fillers which may be
utilized include commercial pigments such as
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Asbestine 325 (U.S. Mica), titanium dioxide, talc,
Hitox (Benilite), and the like. The composition will
also contain an organic pigment, pecan shell flour,
preferably ground to an average size of about 40
micron.
The base coat composition will also contain
suspension agents, thickeners, flow agents and
defoaming agents. Suspension agents include Colloid
711 made by Colloid Co. A preferred thickener is
Cellosize, made by Union Carbide. Flow agents such
as Minusil (P.G.S., Inc.), Super Adit*(Nuodex) may ~e
utilized. Defoaming agents such as Surfynol (Air
Products) may be used.
Typical organic solvents include dimethyl ethanol,
carbitol (diethylene glycol monomethyl ether) methyl
ethyl ketone, acetone, MIBK (methyl isobutyl ketone),
methyl and ethyl alcohol, ethyl acetate, amyl
acetate, and the like. The several portions of any
vehicle used in comparing one of the decorative
coatings are generally composed of the same ~asic
materials although they may have varied amounts of
thinners, solvents, fillers and the like so as to
vary their viscosities and other physical properties,
but there may ~e a com~ination of unrelated resins
used on the same panel to provide texture and growth
lines.
The pulverized pecan nut shell flour utilized in the
base coat composition as an absorption pigment will
be in the form of a fine powder, typically grain size
of about 35 to 45 microns (prefera~ly 40 average
microns).
The particular proportions of the various components
used may be generally in the proportions given a~ove.
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It will be understood however, that various
modifications in proportions and components may ~e
utilized without departing from the scope of the
present invention.
A particularly preferred coating composition
comprises the following:
parts rvolume)
Water 24.88
Dimethyl ethanol 0.19
10 Car~itol 1.63
Styrene-maleic anhydride 0.84
resin SMA-144(H)
Rhoplex AC-507 acrylic resin 41.33
Joncryl 86-acrylic resin 12.75
TiPure*R900, titanium dioxide 0.79
Hitox pigment 2.17
Asbestine 325 pigment 10.46
Nytal*300 talc filler 3.50
Pecan shell flour (40 micron) 2.33
Cellosize QP-09-H thickener 0.18
Defoamer 6-475 (Drew Chemical) 0.23
Surfynol T.G. (Air Products) 0.85
Minusil 10 flour additive 3.40
Super Adit flow additive 0.13
Colloid 711 suspension agent 0.19
In addition to the various pigments mentioned above,
the base coat may contain various typical inorganic
pigments useful for wood grain such as those iron
pigments ranging in color from yellow through red,
reddish brown, brown to black, similar to those found
in natural wood. These iron pigments include yellow
ocher, raw and burnt sienna, and raw and burnt umber.
other useful inorganic color pigments include chrome
yellow, cadmium sulfide, zinc yellow, cobalt blue,
ultramarine blue, iron oxide, chrome green, chromium
oxide green, chromium hydroxide green, lamp black
carbon, and white pigments such as titanium dioxide,
titanium calcium, zinc oxide, zinc sulfide, antimony
oxide, lithopone, etc. Organic pigments may also be
utilized such as toluidine red, phthalocyanine blue
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and green, VanDyke brown, alizarin, madder lake,
lythol red, etc.
After applying the base coat, it is dried, for
example, in a conventional oven to remove the
volatile solvents, thereby forming a hardened base
coat. An ink formulation may then be applied to the
base coat with a roller having a wood grain pattern.
The ink formulation comprises: resins, pigments and
fillers, thickeners, defoaming agents, flow agents,
suspension agents, solvents, and wax.
The resins utilized in the above ink formulation
include acrylic resins such as Joncryl 74, BALAB,
UCAR-SCT 100. The pigments include various pigments
utilized to simulate wood grain colors, as described
above and include specifically yellow 895-000-1801
(Nuodex), burnt umber (I-347), red oxide 895-1003
(Harshaw), Mearlin silk white (an iridescent
pigment). As an absorption pigment Phoschek P/30 may
be utilized. As a tinting agent a tint paste such as
Benzidine yellow (W-1041) may be utilized. A wetting
agent such as glycol ether (PM) is used. Various
solvents may be utilized such as DMAE (Union
Carbide), water and ethylene glycol.
The pigments which are utilized in the ink
formulation will depend upon the color of the wood
grain desired. The pigments must, of course, impart
a color to the ink formulation which is different
from the color of the dried base coat in order to
provide contrast. Usually, colorants which impart
yellow or ~rown tones to the base coat will ~e
useful. Typically, the base coat, after application
of the ink formulation, will be stained with a
conventional wood stain, which usually enhances the
contrast between the base coat and the ink.
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In general, the ink will contain as follows:
~ bY volume
Water 2-8
Organic solvents 1-5
5 Acrylic resins 30-60
Yellow pigment 8-12
Brown pigment 10-20
Red pigment up to 3
Iridescent white pigment up to 1
10 Inert pigment up to 5
Wetting agent 2-8
Wax 5-lS
A typical ink formulation may comprise the following
(parts by volume):
Manufacturer
Joncryl 74 52.24 Acrylic resin Johnson &
Johnson
BALAB 3056A .73 Resin (latex) Witco
Ethylene glycol2.32 SolventChem Central
DMAE .58 SolventUnion Carbide
Tap ~ater 5.15 Solvent
UCAR SCT100 1.20 Resin (latex) Union Carbide
Glycol Ether PM6.41 Wetting agent Ashland
895-000-1801 Yellow 6.22 Pi~ment Nuodex
U-1041 Benzidine
Yellow 4.90 Tint pasteHarshaw
I-347 Bt. Umber16.77 Pigment Harshaw
895-1003 Red Oxide .79 Pigment Nuodex
Mearline Silk ~hite .22 Iridescent pigment Hearl
Phos Chek P/30 fine 2.45 Absorption pi~ment Monsanto
Slip Ayd-459-102910.00 Wax
After application of the graining ink formulation and
air drying, the final product may be utilized as is,
or stained with a conventional wood stain, then
coated with a conventional varnish or other clear
preservative.
The base coat and ink formulation may be applied to
any metal, plastic or wood surface, including paper,
if desired.
Having described the specific em~odiments of the
invention, other modifications and variations will be
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apparent to those of ordinary skill in the art, which
variations and modifications are intended to ~e
within the scope of the present invention.
