U.S. patent application number 11/521988 was filed with the patent office on 2007-01-18 for mineral stains for wood and other substrates.
This patent application is currently assigned to Purecolor, Incorporated. Invention is credited to Stephen B. Auger.
Application Number | 20070011820 11/521988 |
Document ID | / |
Family ID | 25345472 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070011820 |
Kind Code |
A1 |
Auger; Stephen B. |
January 18, 2007 |
Mineral stains for wood and other substrates
Abstract
According to the invention, a metal salt and an oxygen source
are applied to penetrate or impregnate a suitable substrate
sequentially in effective amounts so as to react in contact with
the substrate and produce a mineral compound fixed within the
surface of the substrate. The inventive combination of a mutually
compatible metal salt, oxygen source, and substrate brings about an
in situ reaction, and modifies the substrate to bring about a
lasting desired effect. The mineral compound that is produced
according to the invention is linked to the substrate, is stable
and long-lasting or permanent, and is immobilized or insolubilized
in the substrate. The mineral compound is bound or contained within
and on the surface of the substrate, so it may be said to be
ingrained in the fibers or matrix of the substrate, or embedded
within the substrate. The desired effect is preferably a color. A
wide variety of metal salts may be used depending on the desired
effect. The oxygen source is preferably a peroxide, and the
substrate is preferably a cellulose product such as wood, cotton,
or paper; leather; or masonry. The invention contemplates methods
of treating substrates, treatment kits, and treated products. With
wood products, the invention provides a water-based stain of low
toxicity useful for soft woods.
Inventors: |
Auger; Stephen B.; (Santa
Fe, NM) |
Correspondence
Address: |
MCDERMOTT, WILL & EMERY
4370 LA JOLLA VILLAGE DRIVE, SUITE 700
SAN DIEGO
CA
92122
US
|
Assignee: |
Purecolor, Incorporated
Santa Fe
NM
|
Family ID: |
25345472 |
Appl. No.: |
11/521988 |
Filed: |
September 15, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11131937 |
May 17, 2005 |
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11521988 |
Sep 15, 2006 |
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09932976 |
Aug 21, 2001 |
6905520 |
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11131937 |
May 17, 2005 |
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08865419 |
May 28, 1997 |
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09932976 |
Aug 21, 2001 |
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Current U.S.
Class: |
8/402 |
Current CPC
Class: |
C04B 41/52 20130101;
D06P 1/67375 20130101; D06P 3/3293 20130101; C09D 15/00 20130101;
D06P 1/67333 20130101; D06P 1/67383 20130101; B27K 5/04 20130101;
D06P 1/008 20130101; C04B 41/52 20130101; C04B 41/5007 20130101;
C04B 41/009 20130101; C04B 41/52 20130101; D06P 1/0076 20130101;
C04B 41/009 20130101; C04B 41/70 20130101; C04B 41/5007 20130101;
D06P 1/67366 20130101; C04B 41/65 20130101; C04B 41/009 20130101;
D06P 1/67341 20130101; C04B 41/89 20130101; D06P 1/6735 20130101;
C04B 41/85 20130101; C04B 2111/82 20130101; B27K 5/02 20130101;
D06P 5/001 20130101; D06P 3/60 20130101; D06P 1/67391 20130101;
B27K 3/52 20130101; C04B 41/5007 20130101; C04B 22/068 20130101;
C04B 41/4558 20130101; C04B 22/068 20130101; C04B 41/502 20130101;
C04B 41/502 20130101; C04B 28/02 20130101; C04B 41/502 20130101;
C04B 33/00 20130101; C04B 41/457 20130101 |
Class at
Publication: |
008/402 |
International
Class: |
D06P 3/60 20060101
D06P003/60 |
Claims
1. A kit for imparting a pre-determined color to a wood substrate,
comprising: (a) a solution of a mineral salt, and (b) a solution of
an oxidizing agent, the mineral salt and oxidizing agent solutions
being applied sequentially in effective amounts to the wood
substrate, sequentially penetrating a surface of the wood
substrate, reacting with each other in the presence of the wood
substrate and imparting the color to the wood substrate.
2. A method for treating a wood substrate comprising the steps of:
(a) contacting a surface of a wood substrate with a first
formulation comprising a metal salt and a solvent, (b) Penetrating
the surface of the wood substrate with an effective amount of the
first formulation to penetrate the wood substrate, and sequentially
(c) Contacting the wood substrate with a second formulation
comprising an oxidizing agent and a solvent, (d) Penetrating the
surface of the wood substrate with an effective amount of the
second formulation, (e) Reacting the first and second formulations
with each other in contact with the wood substrate, and (f)
Imparting a stable change to the characteristics of the wood
substrate.
3. The method of claim 2, wherein the oxidizing agent is sodium
peroxide or sodium hydroxide and the solvents in the first and
second formulations are acids, alcohol, water or combinations.
4. The method of claim 2, wherein the metal salt is selected from
the group consisting of salts of iron, silver, zinc, cerium,
copper, gold, magnesium, molybdenum, nickel, tin, chromium,
aluminum, barium, calcium, sodium, potassium, and titanium, and
combinations.
5. The method of claim 2, wherein the metal salt is selected from
the group consisting of salts of aluminum, antimony, beryllium,
bismuth, cadmium, chromium, cobalt, copper, gold, iridium, lead,
magnesium, manganese, mercury, molybdenum, nickel, niobium, osmium,
platinum, plutonium, potassium, rhodium, selenium, silicon, silver,
sodium, tantalum, thorium, tin, titanium, tungsten, uranium,
vanadium, and zinc, and combinations.
6. The method of claim 2, wherein the metal salt is selected from
the group consisting of sulfates, chlorides, perchlorates,
acetates, nitrates, permanganates, thiosulfates, and oxides, and
combinations.
7. The method of claim 2, wherein the metal salt is selected from
the group consisting of silver sulfate, silver perchlorate, silver
nitrate, silver sulfate, iron (II) chloride, zinc perchlorate, iron
(II) perchlorate, iron (II) sulfate, copper acetate, sodium
thiosulfate, magnesium thiosulfate, potassium thiosulfate,
potassium nitrate, potassium permanganate, copper nitrate, copper
II carbonate dihydroxide, copper sulfate, titanium III sulfate,
magnesium nitrate, cerium (III) perchlorate, and cerium nitrate,
and combinations.
8. The method of claim 2, wherein the metal salt is selected from
the group consisting of molybdenum (VI) oxide, zinc sulfate, copper
(II) chloride, nickel perchlorate, nickel sulfate, copper (II)
perchlorate, tin (II) sulfate, tin (I) chloride, chromium (III)
sulfate, aluminum sulfate, cerium (III) perchlorate, zinc peroxide,
titanium hydride, chromium (III) perchlorate, zinc powder,
manganese (II) chloride, aluminum chloride, titanium (IV) chloride,
silver chloride, and titanium (II) sulfate, and combinations.
9. The method of claim 2, wherein the oxidizing agent is sodium
hydroxide.
10. The method of claim 2, wherein the oxidizing agent is selected
from the group consisting of hydrogen peroxide, sodium peroxide,
zinc peroxide, calcium peroxide, barium peroxide, and lithium
peroxide, sodium hydroxide and combinations.
11. The method of claim 2, wherein the wood substrate is a close
grain wood.
12. The method of claim 2, wherein the wood substrate is a
wood-like product.
13. The method of claim 2, wherein the wood substrate is selected
from the group consisting of hardwoods, soft woods, porous surface
woods and close grain wood, and manufactured wood products.
14. The method of claim 2, wherein the wood substrate is a hardwood
manufactured wood product.
15. The method of claim 2, wherein the wood substrate is a soft
wood manufactured wood product.
16. The method of claim 2, wherein the wood substrate is a pine
wood.
17. The method of claim 2, wherein the effect imparted to the wood
substrate is a color.
18. The method of claim 2, wherein step (a) is performed before
step (c).
19. The method of claim 2, wherein step (c) is performed before
step (a).
20. The method of claim 2, further comprising the step of drying
the wood substrate between step (b) and step (c).
21-56. (canceled)
Description
[0001] This application is a division of application Ser. No.
08/865,419 filed May 28, 1997.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a water-based mineral stain for
wood and other substrates.
[0003] More specifically, the invention relates to a process in
which a metal salt and an oxygen source react with the substrate to
provide a stable color or other desired effect such as preserving
the substrate.
[0004] Many commercial stains readily available on the market are
oil or solvent-based and/or contain hazardous chemicals subject to
increasing environmental regulation and health concerns. There is a
growing need for water-based colorants and finishes that contain no
hazardous chemicals. Federal and state initiatives are leading to
bans on stains using volatile organic compounds (e.g. petroleum,
mineral spirits, toluene, or benzene).
[0005] Most water-based products for coloring and finishing wood
and other materials are primarily based upon a pigment or dye
suspended in a binder such as acrylic resin, which is spread onto
the wood surface and held in place by the binder. Such products,
although less toxic, exacerbate a problem of all conventional
stains, namely that while coloring a wood such as pine they sink in
more deeply into the soft pulp and are repelled by the harder wood
around the annual growth rings formed during the dormant period in
a tree's growing season. For example, stains such as Minwax.TM. can
color pine to a maple-like general color, but in doing so emphasize
the distinctive grain-markings characteristic of pine. Such
products tend to produce marginal results and an uneven staining
pattern. There would be great advantages for a stain capable of
coloring both hard and soft woods evenly allowing for a maple-like
overall color with a much more subtle grain pattern, thereby
allowing a soft wood to mimic the appearance of a hard wood more
effectively. Also, water-based stains tend to raise wood grain,
requiring additional sanding.
[0006] There is a need for a coloring process having the
environmental benefit of allowing rapidly growing, sustainably
harvestable woods such as pine and other fast-growing and therefore
"renewable" wood resources to give the visual appearance of
endangered hardwoods such as mahogany, ebony, redwood, and other
species that are increasingly rare and expensive.
[0007] The construction, furniture, and woodworking industries need
new improved water-based stains effective for soft woods. Likewise,
there is a need for environmentally beneficial coloring processes
for wood products such as paper and cardboard, for fabrics for
clothing and upholstery, and for manufactured polymer products.
[0008] Conventional stains take a relatively long time to dry and
can only be applied in temperatures at or above 55 degrees F. There
is a need for a stain that can be applied outside this range, for
example, for exterior woodwork in a colder climate.
[0009] Conventional stains are made up of a binder and a pigment or
dye. Many of these coloring agents are "fugitive," fading over
time, especially in exterior settings. A stable coloring agent that
is permanent and does not fade over time and even becomes richer
and slightly darker would be an improvement over conventional
stains.
[0010] Conventional stains can be used on dry, cured wood only.
There is a need for stains that can be applied to damp or "green"
un-cured wood. Conventional stains coat the surface of aromatic
woods such as cedar, preventing the natural aroma from being
released by the wood. There are advantages to stains that leave a
wood fully aromatic. Oil-based conventional stains can be difficult
to over-coat with water-based acrylic finishes. A stain that can be
over-coated with any type of oil or water-based finish would have
pronounced advantages.
[0011] Stains used to simulate wood aging, such as Cabot Stains
Bleaching Oil.TM. can only be used for exterior use and the
appearance of aging of the wood takes many months from application.
An aging treatment that can be used indoors and occurs immediately
has clear advantages. Other aging processes require the use of
harsh acids, bleaches and other toxic chemicals and require complex
manual wood-distressing techniques such as multiple layering of
different stains to mimic grain patterns of aged wood. Preferable
would be an aging treatment that is non-toxic and can be applied
easily by a layman.
[0012] Some coloring processes have been developed to compensate
for the unattractive green color of CCA (copper-chromium-arsenic)
pressure-treated preserved lumber, such as Leach, U.S. Pat. Nos.
4,752,297 and 4,313,976. These processes rely on organic acids and
other organic compounds. They are concerned primarily with
preservation of wood, are able to produce only a limited color
palate, and are not of general applicability.
[0013] A process of using an aqueous solution of an alkaline earth
metal base to treat wood is described in Gaines et al. U.S. Pat.
No. 4,757,154. This method requires immersing wood at high
temperature and pressure and sanding to remove an unattractive
deposit, so it is not a viable method for staining wood. Some
woodworkers soak wood in a solution of iron-rich fertilizer to
produce a dusty gray tone. The coloring is unstable, uneven, fades
over time, leaches out if exposed to moisture, and if overcoated
creates an unattractive residue, so it is not in regular use.
SUMMARY OF THE INVENTION
[0014] According to the invention, a metal salt and an oxygen
source are applied to penetrate or impregnate a suitable substrate
sequentially in effective amounts so as to react in contact with
the substrate and produce a mineral compound fixed within the
surface of the substrate. The inventive combination of a mutually
compatible metal salt, oxygen source, and substrate brings about an
in situ reaction, and modifies the substrate to bring about a
lasting desired effect. The mineral compound that is produced
according to the invention is linked to the substrate, is stable
and long-lasting or permanent, and is immobilized or insolubilized
in the substrate. The mineral compound is bound or contained within
and on the surface of the substrate, so it may be said to be
ingrained in the fibers or matrix of the substrate, or incorporated
or embedded within the substrate. The desired effect is preferably
a color. A wide variety of metal salts may be used depending on the
desired effect. The oxygen source is preferably a peroxide, and the
substrate is preferably a cellulose product such as wood, cotton,
or paper; leather; or masonry. The invention contemplates methods
of treating substrates, treatment kits, and treated products.
[0015] This invention satisfies a long felt need for a water-based,
non-toxic stain for woods and other substrates that provides a
permanent even coloring effect. The invention is in the crowded and
mature art of colorants, preservatives, and finishes for wood and
other substrates, yet it has not previously been discovered or
used.
[0016] The wood-stain industry has been searching for ways to
reduce toxic chemical use, to more effectively stain woods such as
pine that are difficult to work with and relatively inexpensive,
and to simulate the appearance of aging. The demand is such that
any feasible process tends to be put into use.
[0017] This invention succeeds where previous efforts have failed.
It avoids the need for volatile organic solvents and toxic
compounds, heat, or pressure--elements employed in the prior
art--without loss of ability, and indeed with improved results. It
can be applied to a wide variety of woods and other substrates with
excellent, permanent results. It works quickly in environments and
temperatures inappropriate for conventional treatments, and is
simple enough to be used by an amateur.
[0018] This invention solves previously unrecognized problems,
including how to react a substrate with a soluble mineral salt and
an oxygen source to color the substrate; how to satisfy consumer
aesthetics limiting the substitutability of sustainable woods for
endangered species; and how to use a single staining system for a
wide variety of wood and non-wood substrates. This invention also
solves the problem of evenly staining and rapidly aging soft woods
and green woods and related materials, which was generally thought
to be insoluble. The advantages provided by the invention could not
previously have been appreciated, such as its adaptability to a
variety of overcoat finishes, the ability to stain without
appreciably raising wood grain, and its retention of the aromatic
quality of the substrate.
[0019] This invention differs from the prior art in modifications
which were not previously known or suggested, such as using mineral
salts and peroxide solutions to produce surprising coloring
effects. Indeed, this invention is contrary to the teachings of the
prior art, which favors one step treatments using colored pigments,
rather than two step processes whereby the color is developed and
stabilized during the process.
[0020] The inventive approach to the coloring and preserving of
cellulose and other materials is a process whereby a water-soluble
mineral salt is saturated into the substrate material and
subsequently oxidized and somehow linked or bonded to that
material. This process has no precedent in the marketplace and
provides important advantages in both the commercial and consumer
markets. In a preferred embodiment, the inventive stains
are-completely water-based. The process does not require a binder
of any kind, petroleum products, organic solvents, acrylic resins,
dyes, or other expensive or toxic materials. The component
materials have low-impact on both the environment and human heath.
The unique characteristics of the product, its permanence even in
exterior applications, its ability to evenly stain extremely soft
woods and penetrate extremely hard woods, its simulated aging of
wood, and the richness of the colors achieved will appeal even to
those completely unconcerned about its environmental and health
advantages.
[0021] According to the invention, a method for coloring a
substrate comprises:
[0022] (a) applying a preparation of a metal salt to the substrate,
and
[0023] (b) separately applying a preparation of an oxygen source to
the substrate,
such that the metal salt and the oxygen source penetrate the
substrate and react in contact with the substrate to produce a
stable, water-insoluble stain or other fixed physical
characteristic in the substrate.
[0024] Step (a) may be performed before or after step (b), and
there may be a step of drying the substrate between the two steps.
Preferably the preparations are aqueous solutions and are applied
between the freezing point and boiling point of the solutions as
determined under the particular process conditions selected for the
method. The method may further comprise applying a sealing coat
over the substrate surface.
[0025] In a preferred embodiment, the substrate is a sustainably
harvested wood, the stain is relatively uniform, the metal salt is
of low toxicity and not considered hazardous, the reparations of
metal salt and oxygen source are water-based solutions, and the
oxygen source eaves essentially no residue. Preferably, the metal
salt preparation and the oxygen source reparation are aqueous
solutions.
[0026] The metal salt may be any appropriate mineral salt and is
preferably a salt of iron, silver, zinc, cerium, copper, magnesium,
molybdenum, nickel, tin, chromium, aluminum, and titanium, r a salt
of antimony, beryllium, bismuth, cadmium, cobalt, gold, iridium,
lead, manganese, mercury, niobium, osmium, platinum, plutonium,
potassium, rhodium, selenium, silicon, sodium, tantalum, thorium,
tungsten, uranium, vanadium, or a combination. The principal
purpose of staining with the mineral may be to impart a desirable
color to the substrate, to preserve the substrate, or both.
[0027] The metal salt is preferably selected from sulfates,
chlorides, perchiorates, permanganates, thiosulfates, acetates,
nitrates, as well as oxides that are subject to reduction to
release a metal ion capable of reacting with the oxygen source in
the presence of the substrate to produce a color. Other salts that
may be suitable include halides, phosphates, carbonates, nitrates,
oxalates, silicates, tartrates, formates, chromates, organic salts,
and the like, so long as the metal ion or compound is sufficiently
solublet penetrate the substrate and is able to react with the
oxygen source preparation to produce the desired color or other
desired fixed quality in the substrate.
[0028] Preferred metal salts are silver sulfate, iron (II)
chloride, zinc perchlorate, cerium (III) perchlorate, iron (II)
perchiorate, iron (II) sulfate, silver perchlorate, copper acetate,
magnesium nitrate, and cerium nitrate. Other preferred metal salts
are molybdenum (VI) oxide, zinc sulfate, copper (II) chloride,
nickel perchlorate, nickel sulfate, copper (II) perchlorate, tin
(II) sulfate, tin (I) chloride, chromium (III) sulfate, aluminum
sulfate, cerium (III) perchlorate, zinc peroxide, titanium hydride,
chromium (III) perchlorate, zinc powder in combination with
titanium salts, manganese (II) chloride, aluminum chloride,
titanium (IV) chloride, silver chloride, and titanium (II)
sulfate.
[0029] Preferably the oxygen source is a peroxide. It may be
hydrogen peroxide, sodium peroxide, zinc peroxide, barium peroxide,
calcium peroxide, or lithium peroxide. The oxygen source may
include a hydroxide such as sodium hydroxide. The oxygen source is
capable of penetrating the substrate and reacting with the metal
salt to impart a stable color or other physical characteristic to
the substrate.
[0030] The substrate is preferably a building material or textile
and is preferably a cellulosic material such as a soft wood, hard
wood, bamboo, rattan, or other cellulose product, such as cotton,
paper, cardboard, or the like. The substrate may be previously
coated, such as a latex painted surface. The substrate may be
leather, fabric, or porous plastic; or it may be a masonry material
such as ceramic, plaster, cement, concrete, stone, brick, or a
combination. Preferably the effect achieved in the substrate is a
color, typically an earth tone. The substrate is one which can be
penetrated and contacted sequentially with the metal salt
preparation and the oxygen source preparation so as to produce the
desired color or other effect bound stably within the substrate.
Preferably the substrate is wood or is a wood-like product, meaning
a hard fibrous, cellulose-based product from trees, bamboo, reeds
or other agricultural sources, including fiber board, plywood, and
veneer.
[0031] The metal salt preparation and/or oxygen source preparation
may further comprise a compatible additive selected from the group
consisting of thickener, alcohol, emulsifier, coloring agent,
pigment, dye, bleach, sealer, finishing agent, tint, acrylic
finish, latex finish, polyurethane, alcohol, gelling agent,
tabletting agent, surfactant, buffer, citric acid, tannic acid,
acetic acid, other acid, base, color, salt, stabilizer,
antimicrobial, antifungal, insecticide, insect repellant,
ultraviolet protectant, and fire retardant. Other additives now
known or hereafter available to a person of skill in the art may be
employed so long as they do not interfere with the operation of the
components of the invention and have suitable shelf life and other
characteristics.
[0032] The invention contemplates a colored or otherwise altered
substrate produced by the method of the invention. The colored or
altered substrate, at its surface or within, has a stable
manufactured composition that imparts color or other desirable
characteristics, the composition comprising the products of a
chemical reaction in contact with the substrate, between a metal
salt, and an oxygen source.
[0033] The invention further contemplates a kit for treating a
substrate, comprising (a) a metal salt preparation, and (b) an
oxygen source preparation, the preparations being adapted to
penetrate the substrate when applied, and both preparations, when
applied sequentially in effective amounts, being adapted to react
with each other to produce a compound fixed on or in the substrate
that is stable, and water-insoluble and imparts a color or other
desirable characteristic.
[0034] The metal salt preparation is preferably an aqueous solution
comprising between about 0.001% and about 20% (w/v) more preferably
about 0.025% to about 8% metal salt. The oxygen source preparation
is preferably an aqueous solution comprising between about 0.1% and
about 50% (w/v) peroxide, more preferably between about 0.3% and
about 15%. The concentration of either component may be the
point-of saturation of a solution or a higher concentration of an
appropriate suspension.
[0035] Further details, objectives, and advantages will become
apparent from a consideration of the following description.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] In describing preferred embodiments of the present
invention, specific terminology is employed for the sake of
clarity. However, the invention is not intended to be limited to
the specific terminology so selected, and it is to be understood
that each specific element includes all technical equivalents which
operate in a similar manner to accomplish a similar purpose. For
the sake of simplicity, this description principally addresses
application to wood products. In most cases, however, processes and
compositions discussed are also applicable to a wide variety of
non-wood products.
[0037] The inventive process is a two-step process preferably
involving a non-toxic, water-based mineral solution and a low
toxicity water-based oxidizing solution applied sequentially to
unfinished wood products. The process may be adapted for the
coloring and finishing of wood-like products such as bamboo or
rattan, paper, recycled cellulose products, cotton and other
cloths, leather, certain porous plastics, tile, cement, and other
masonry, and other substrate substances.
[0038] The user first brushes, sprays, or otherwise applies a
water-based solution "A" onto a wood or other product, lets the
product dry for about 5-30 minutes, depending on temperature and
humidity, then applies a second water-based solution "B". Color
change begins immediately and when the B solution dries, in another
approximately 5-30 minutes, the product is permanently stained. The
solutions may also be applied by soaking the substrate in the
solution, at standard temperature and pressure or at either extreme
or combinations as with typical pressure treatments for lumber to
ensure thorough penetration of thicker substrates.
[0039] The inventive process can simulate the look of other,
generally more expensive woods (i.e. making pine look like maple,
alder look like walnut, or bamboo plywood look like oak). In
particular, the coloring process can provide stains that simulate
increasingly endangered woods such as mahogany, ebony, and
redwood.
[0040] In another application, the process can be used to give new
wood an aged appearance for aesthetic reasons, or to allow the
unobtrusive introduction of new wood into antique furniture,
architectural antiques, fences or shingles that are in need of
refurbishment. In such applications, it may be advantageous to
distress the surface with rough sanding, sand blasting, chiselling,
saw marks, and so on, to allow the minerals to soak in and provide
irregular staining. In other applications, it is preferable to
maximize the uniformity of the staining, although the stain tends
to be somewhat darker around knots and ring areas even with a
smooth surface. Nonetheless, staining according to the invention
may be uniform, in the sense that it is more even than conventional
water-based stains.
[0041] The A solutions contain a variety of mineral salts (such as
a variant of the iron-rich compounds found in nutritional
supplements) and other natural compounds that soak into the
wood-surface readily. The B solutions contain an oxidizing agent,
such as dilute peroxides similar to the hydrogen peroxide found in
many medicine cabinets. Preferred B solutions are somewhat more
concentrated.
[0042] Although the invention is not intended to be limited to the
mechanism of action, it is believed that the oxygen source causes
an oxidation reaction, bonding the minerals in solution A to or
among the cellulose fibers in the wood, or other matrix material of
a substrate, a process referred to here as "crosslinking." The
chemical nature of the crosslinking reaction is suggested by the
fact that a color change results from the combination of solution
A, solution B, and the substrate. The resulting color, unlike the
clear solutions and their components, is not water-soluble. Also,
typically if solutions A and B are mixed without first applying
them to the substrate, they throw an unattractive gray-black or
gray-brown sediment which is not useful for staining according to
the invention. At high strengths and with peroxides, such a
reaction is accompanied by bubbling as oxygen is released from the
peroxide.
[0043] The process involves saturating the fibers of a wood or
other product matrix with a solution of minerals in a water-soluble
form and then oxidizing said minerals in the fibers or matrix to
change the color, texture, and general appearance of the wood or
other properties. It is believed that the coloring process of the
invention renders mineral salts into a stable, insoluble form,
perhaps an oxide, coordination compound, or other water-insoluble
compound or complex, referred to here as a cross linked
compound.
[0044] The metal salt formulation soaks into the substrate,
impregnating it with mineral ions, which are then converted by the
oxygen source into an insoluble coloring compound. Thus, a metal
oxide may serve as a metal salt according to the invention, and is
contemplated within that definition, if it is solubilized with an
acid, applied so as to penetrate into a substrate, and then reacted
with an appropriate oxygen source to generate the desired color or
other effect. With soluble oxides such as molybdenum IV oxide, the
metal oxide may be soaked into the substrate directly, and then
reacted to produce a color. Also, solution A may include a
combination of a salt of one metal such as titanium chlorate and an
elemental metal, such as zinc powder, such that the elemental metal
is oxidized by the salt to produce a metal salt which then reacts
according to the invention.
[0045] The coloring agent according to the invention may associate
physically or chemically with the substrate, via absorption,
mechanical admixture, entrapment, polar attraction, or covalent
bonding. With cellulosic and leather products, it is assumed that
the reaction involves the cellulose or collagen matrix of the
substrate article, although it would not affect the scope of the
invention if the colored compound remains physically trapped in the
matrix of such substrates, without reacting chemically with them.
With masonry, the substrate may or may not react with the metal
salt and oxygen source, so long as the colored compound is fixed
insolubly within the substrate. The scope of the invention is not
intended to be limited to any of these supposed mechanisms of
action, however.
[0046] The invention also encompasses methods and compositions for
imparting other desired stable physical effects to a substrate,
where color may be a secondary factor. For example, with certain
combinations of metal salts and oxygen sources, the substrate may
have an improved texture, conductivity, photosensitivity,
anti-fungal, antimicrobial, insect repellant, or fire retardant
quality, as a result of treatment according to the invention. Thus
the scope of the intention may encompass a method for imparting a
desirable stable physical change by sequentially applying
preparations A and B to the substrate and allowing them to react so
as to fix or bond the reaction product to or within the
substrate.
[0047] In some cases, the B solution is applied before the A
solution in order to obtain a different effect. Different mineral
solutions and different oxidizing agents create markedly different
effects on wood, and these finishes can be customized for specific
application to a wide variety of materials.
[0048] The invention relates to compositions and kits comprising
the various A and B solutions prepared by combining water soluble
or other mineral salts, oxidizing agents, and other substances into
an aqueous solution.
[0049] The product has a variety of commercial applications
including: wood stain, as an alternative to petroleum, acrylic, and
latex wood finishes; a wood aging system, to make new wood take on
the appearance of old wood; stain for wood-like products, to color
and preserve wood-like products such as bamboo; cloth stain, to
color cloth, hemp, flax, textiles, leather, and other similar
products; wood or other substrate preservation through
anti-microbial or anti-fungicidal effects; and masonry stain: to
color tile, cement, concrete, brick, stone, and other similar
products. The invention can be used both indoors and outdoors, for
wood and non-wood products. As can be appreciated, the metal salt
can be selected to provide desirable preservative, antifungal,
and/or insecticidal properties in addition to a color effect, or
can be combined with known preservative treatments. In some
applications, the color may be secondary to the ability of the
oxygen source to bind or link the metal ion into the substrate
according to the two step process of the invention.
[0050] A kit according to the invention can be distributed in two
containers such as plastic bottles, one for the A solution and one
for the B solution. Bottles A and B can preferably contain a
concentrated solution of key mineral salts or oxidizing agents
dissolved in water, which the end-user will dilute in a gallon or
other volume of water. Alternatively, the product may be
distributed in powder or tablet form, requiring the end-user to
dilute fully with water. The product can be distributed in fully
diluted liquid form, ready to use, which increases shipping costs
but reduces variability due to the type of water used and dilution
techniques. These decisions can readily be made by a person of
ordinary skill depending on acceptance of the various techniques
among consumers (such as professional or amateur markets) and the
relative difficulty of maintaining certain chemicals' shelf lives
in aqueous versus dry conditions. Preferred formulas make use of
only non-toxic substances such as iron and silver sulfates and
avoid toxic heavy metals such as chromium, cobalt, and lead, which
minimize regulatory oversight, and shipping, labelling, and
disposal requirements.
[0051] Preferred applications involve water-soluble solutions of
minerals of low toxicity, usually in the form of mineral salts such
as iron chloride in the A solution, and sodium peroxide or hydrogen
peroxide as the oxygen source in the B solution. More toxic metals
may also be used for an appropriate result, although they require
additional precautions in handling and disposal. Other oxygen
sources may be used, and the invention may be carried out in
preparations other than water or aqueous solutions. For example, a
gel, paste, emulsion, or other thick preparation may be used for
either or both components, so long as such a formulation is able to
deliver the metal salt and oxygen source into the substrate in a
reactive form. Typically, such a thick preparation would be an
aqueous solution, although an emulsion with an oil or a suspension
may be appropriate in certain applications.
[0052] In a preferred embodiment, to form the various preparations
of Solution A, a measured weight of the mineral or minerals is
mixed in a volume of purified water. To form the iterations of
Solution B, liquid hydrogen peroxide or powdered sodium peroxide
are mixed in a volume of water. Alternatively, sodium hydroxide is
added to a hydrogen peroxide solution and may be neutralized or
buffered if desired. Certain other compounds may serve as an oxygen
source according to the invention, such as citric acid on other
organic and inorganic acids, provided that they react with an
appropriate metal salt according to the invention in contact with
the substrate to produce the desired effect.
[0053] The first step in applying the mineral stain is to apply a
sufficient amount of Solution A onto the wood or other substrate so
that it penetrates, using a brush, pad, roller, spraying device or
other suitable method. The solution is generally clear, translucent
or slightly cloudy, and alters the color of wood much the same way
the application of water would. Some of the A solutions are orange
or pink, some milky, some gray. When applied, however, in thin
coatings, there is no appreciable color until the oxygen source is
applied. Optionally colorants, thickeners, surfactants, and other
additives may modify the appearance of the A solution. When the
Solution A dries, in 5-30 minutes depending on temperature and
humidity etc., the wood looks much as it did before anything was
applied to it. A slight graying may be apparent.
[0054] The next step is to apply Solution B to the wood or
substrate in much the same manner as Solution A. With a strong
Solution B, the color in the wood changes immediately. With weaker
solutions, the color comes on slowly, over five minutes or so. The
process is reminiscent of making photographic film prints, or
watching an instant photograph develop, or making invisible ink
become visible. Strong iterations of Solution B have a greater
tendency to show brush marks, which can be a negative or positive,
depending on the effect desired. The final depth of color in the
stained wood is more dependent on the concentration of minerals in
Solution A.
[0055] It is possible, in addition to mixing two or more mineral
salts in an A solution or two peroxides in the B, to apply fast one
and then another A, or first a hydrogen peroxide-based and then a
sodium peroxide-based B solution. Thus two basic steps of the
process might, for certain effects, such as highlighting raised
areas with a different color, etc. involve more than two steps.
[0056] The color and tone of the varying wood samples discussed
below are described in words but the visual impression of two
different samples of wood treated with two different formulas might
both be described as "gray brown" though they actually create quite
different nuances of visual impression. The colors produced
according to the invention are generally earth tones, by which is
meant the palate relating to brown, including gray, orange, yellow,
red, green and blue variants, ranging from light to virtually
black. Opalescent or iridescent effects may be achieved. Brighter
coloring effects may also be achieved, as with aluminum oxides.
Gray is a preferred effect for simulated aging. The effects may be
modified by distressing the surface of the wood to simulate an aged
appearance, or by adding pigments and other coloring agents.
[0057] The following mineral salts and oxides have been used
according to the invention to stain wood: barium sulfate, calcium
sulfate, cerium III nitrate, cerium III perchlorate, copper II
nitrate, copper II acetate, copper II carbonate dihydroxide, copper
sulfate, iron II sulfate, iron II perchlorate, iron II chloride,
sodium thiosulfato, magnesium thiosulfate, potassium thiosulfate,
potassium nitrate, potassium permanganate, silver sulfate, silver
perchlorate, silver nitrate, titanium III sulfate, and zinc
perchlorate.
[0058] Other mineral salts that may be used according to the
invention include: aluminum potassium sulfate, molybdenum (VI)
oxide, zinc sulfate, copper (II) chloride, nickel perchlorate,
nickel sulfate, copper (II) perchlorate, tin (II) sulfate, tin (I)
chloride, chromium (III) sulfate, aluminum sulfate, titanium
hydride, chromium (III) perchlorate, zinc powder, manganese (II)
chloride, aluminum chloride, titanium (IV) chloride, silver
chloride, and titanium (II) sulfate.
[0059] Other minerals capable of reacting with an oxygen source in
contact with a substrate to color the substrate or provide other
effects according to the invention may be selected from salts of
elements of columns 2 through 6 of the Periodic Table of the
Elements, including the transition elements, Lanthanides, and
Actinides. Preferably, the metal is selected from aluminum,
antimony, beryllium, bismuth, cadmium, chromium, cobalt, copper,
gold, iridium, lead, magnesium, manganese, mercury, molybdenum,
nickel, niobium, osmium, platinum, plutonium, potassium, rhodium,
selenium, silicon, silver, sodium, tantalum, thorium, tin,
titanium, tungsten, uranium, vanadium, and zinc.
[0060] As applied to wood and other substrates, the invention may
employ any water-soluble mineral salt or oxidized mineral compound
soluble in solvents such as acids, alcohols, or other aqueous
substances. It may employ any oxidized mineral compounds capable of
reacting with an oxygen source and a substrate to form a colored
compound linked to the substrate. Such compounds are referred to
here collectively for convenience as metal salts, although some of
the mineral elements are not metal, and some of the compounds are
oxides, not salts.
[0061] The oxygen source may be any oxidizing agent capable of
oxidizing mineral salts according to the invention in the presence
of a substrate of wood, bamboo, leather, cellulose, and other
suitable substrates. Preferred oxygen sources are-peroxides,
compounds that include the peroxy (--O--O--) group. Peroxides form
hydrogen peroxide upon solution in water. The invention may employ
any inorganic or organic peroxide, including those described in
Kirk Othmer, Concise Encyclopedia of Chemical Technology, pp.
845-850 (1985), which is incorporated herein by reference. Thus,
the oxygen source may be a superoxide or ozonide, or a peroxyacid.
It may also be a hypochlorite or chlorine dioxide, although these
are relatively toxic and unstable.
[0062] A person of ordinary skill may vary and control for the
following parameters to obtain a desired result. The
color-producing reactions and resultant color and textural
appearance of the wood varies widely with the different minerals
used in Solution A. They are reproducible, however, and may be
selected as desired to provide a particular appearance. The effect
may vary with the purity of the minerals used in Solution A. The
examples below used Reagent Grade but Technical Grade or lower
grades are suitable for a commercial application.
[0063] The effect varies with the oxygen sources in solution B.
Sodium peroxide and hydrogen peroxide and combinations give
desirable effects. Other inorganic and organic peroxides and oxygen
sources are suitable.
[0064] The effect may vary with the source of water. The examples
use purified water. Distilled water versus mineral-rich well water
may result in slightly different effects. In general, however, the
use of tap water or deionized water gives adequate results. In
other cases, modifying the pH or ionic strength with additives may
be desirable.
[0065] The effect may vary with the solution in which the minerals
or peroxides are dissolved or suspended. In the examples below,
water is used, but other liquids could be used, some with
non-water-soluble minerals. Instead of a solution, the minerals
could be dissolved or suspended in a gel, wax, lotion, or creme and
rubbed into the wood or substrate, so long as adequate penetration
results. The wood or substrate must also be susceptible to
penetration by an appropriate oxygen source, and the vehicle must
be compatible in that it does not interfere with the
color-producing reaction.
[0066] The effect may vary with the concentrations of the
solutions. Generally, more dilute solutions create lighter color
density but in some cases they actually give the appearance of a
different color.
[0067] The effects produced do not vary appreciably with the
ambient temperature at which the solutions are applied. The process
can be followed at any temperature above or even slightly below
32.degree. F. or the freezing point, and the stained-wood is dry
and ready to be top-coated (if desired) in less than an hour,
depending on humidity and temperature conditions. For extremely
low-temperature applications, minerals and/or oxidizing agents can
be dissolved in alcohol or other non-water solutions. In the
examples below, the tests took place at room temperature, but
experiments at near-freezing temperatures seemed to create the same
result. The invention can also be applied at upper extremes of
temperature or high or low pressure, if appropriate.
[0068] Reactions and resultant color and textural appearance of the
substrate vary with the substrate material. In the examples below,
sugar pine was used but the method of the invention has been
successfully applied to northern pine, ponderosa pine, alder,
poplar, maple, oak, ash, cedar; cherry, walnut, obinji and other
woods and, of course, the results vary widely with the color, tone,
and character of each type of wood. Successful demonstrations have
also been done on ply bamboo, cotton, leather, and masonry. Ply
bamboo is a very hard wood product, does not stain well with
conventional products but is susceptible to coloring according to
the invention. Other substrates are suitable so long as they are
made of a material capable of binding the mineral salt in the
presence of the oxygen-source according to the invention.
[0069] Effects may vary with the order of application of solutions
A and B. In general, starting with B and finishing with A yields a
similar color but less nuances of wood grain, which could be
preferable in certain applications. In simulating aged wood, for
example, the A solution should be applied first. For:a non-aged
appearance and an even color, the B solution can be applied first.
It may be that applying B first makes for a more superficial
penetration of the linked color in the wood, but this may be
appropriate for thin substrates. With porous substrates, such as
fabric or leather, it is preferable to soak the substrate in the
solutions to ensure even staining.
[0070] The results also vary with the additives included in
solutions A or B such as pigments or dyes, citric acid, bleaches,
alcohols, solvents, thickeners, tableting agents, finishing agents
such as an appropriate overcoat of acrylic and other resins or
polyurethanes that might oxidize and seal the wood simultaneously.
Alternatively, an over coat sealer may be applied over the stain.
An overcoat may optionally be included into Solution B (or solution
A if that is applied last).
[0071] Stained wood according to the invention has been subjected
to accelerated weathering situations, exposure to sun, hot water,
freezing temperatures, and submersion in water. It is resistant to
fading and actually is made slightly darker or warmer in tone on
exposure. These tests show that the product produces a remarkably
permanent stain suitable for use by professionals and amateurs, for
interior and exterior application.
EXAMPLES
[0072] In all the formulas below, Solution A is made up as a
solution of mineral in water. Concentrations are given as percent
(weight/volume), or the number of grams of mineral and the volume
of water is given. Solution B is made up of a 15% (v/v) solution
hydrogen peroxide or a 0.3% sodium peroxide solution (made from 3.0
grams per liter of water). In all these cases, the substrate is
Sugar Pine unless specifically mentioned otherwise. Different woods
or other substrates work equally well, but the colors are somewhat
different. These experiments were conducted with an ambient
temperature around 65-75 degrees F. Upon application of the B
solution, color appeared in from less than one second to up to one
minute. Experiments at different temperatures have only marginally
different results. Different strengths of Solution B speed or slow
the reaction, but result in similar end colors. The key variable
determining the color is the mineral or minerals in Solution A.
[0073] In Examples 1-10, the given mass of mineral was dissolved in
1 liter water.
Example 1
[0074] Solution A: 0.25 g Silver Sulfate (Ag.sub.2SO.sub.4)
[0075] Solution B: Sodium Peroxide
[0076] Result: Medium density golden-brown
Example 2
[0077] Solution A: 2.0 g Iron (II) Chloride
(FeCl.sub.2.XH.sub.2O)+0.5 g Silver Sulfate (Ag.sub.2SO.sub.4)
[0078] Solution B: Sodium Peroxide
[0079] Result: Medium density gray-brown, aged appearance
[0080] Solution B: Hydrogen Peroxide
[0081] Result: Medium density warm yellow-brown
Example 3
[0082] Solution A: 1.5 g Iron (II) Chloride
[0083] Solution B: Hydrogen Peroxide
[0084] Result: Light density warm brown with reddish tone
Example 4
[0085] Solution A: 1.5 g Iron (II) Chloride+1.0 g Zinc Perchlorate
(Zn(ClO.sub.4).sub.2.6H.sub.2O)
[0086] Solution B: Hydrogen Peroxide
[0087] Result: Medium density orange-brown with dark brown to black
highlights in the crossgrain
[0088] Solution B: Sodium Peroxide
[0089] Result: Medium density gray with black in the crossgrain
Example 5
[0090] Solution A: 1.5 g Cerium III Perchlorate
(Ce(ClO.sub.4).sub.3.6H.sub.2O)
[0091] Solution B: Hydrogen Peroxide
[0092] Result: Light to medium density yellow-brown
Example 6
[0093] Solution A: 2.0 g Iron (II) Perchlorate
(Fe(ClO.sub.4).sub.2.6H.sub.2l O)
[0094] Solution B: Hydrogen Peroxide
[0095] Result: Light to medium density warm brown, aged
appearance
Example 7
[0096] Solution A: 2.0 g Iron (II) Perchlorate
(Fe(ClO.sub.4).sub.2.6H.sub.2O)+0.25 g Silver Sulfate
(Ag.sub.2SO.sub.4)
[0097] Solution B: Hydrogen Peroxide
[0098] Result: Medium density warm brown aged appearance
[0099] Solution B: Sodium Peroxide
[0100] Result: Medium density gray brown aged appearance
Example 8
[0101] Solution A: 1.5 g Iron (II) Sulfate
(FeSO.sub.4.7H.sub.2O)
[0102] Solution B: Hydrogen Peroxide
[0103] Result: Medium density warm-brown, aged appearance
[0104] Solution B: Sodium Peroxide
[0105] Result: Medium density warm gray
Example 9
[0106] Solution A: 0.5 g Silver Perchlorate
(AlgCO.sub.4.7H.sub.2O)
[0107] Solution B: Sodium Peroxide
[0108] Result: Medium density warm brown, aged appearance
Example 10
[0109] Solution A: 1.0 g Iron (II) Sulfate+0.5 g Silver
Perchlorate
[0110] Solution B: Hydrogen Peroxide
[0111] Result: Medium density warm brown, aged appearance
[0112] Solution B: Sodium Peroxide
[0113] Result: Medium density gray brown aged appearance
Example 11
[0114] Solution A: Copper Acetate, 1 gram diluted in 50 ml of
H.sub.2O
[0115] With Hydrogen Peroxide: warm orange-brown, medium
density
[0116] With Sodium Peroxide: no reaction
Example 12
[0117] TABLE-US-00001 Solution A: Iron(II) Chloride: 0.5 grams and
Silver Sulfate 0.5 grams in 50 ml H.sub.2O With Hydrogen Peroxide:
gray-brown, medium density With Sodium Peroxide: orange brown, dark
density
Example 13
[0118] TABLE-US-00002 Solution A: Iron (II) Perchlorate: 8 grams
and Silver Sulfate 0.25 grams in 100 ml H.sub.2O With Hydrogen
Peroxide: dark aged appearance With Sodium Peroxide: nearly black,
ebony-like appearance
Example 14
[0119] TABLE-US-00003 Solution A: Iron (II) Perchlorate: 4 grams
and Silver Sulfate 0.1 grams in 100 ml H.sub.2O With Hydrogen
Peroxide: warm orange brown, medium density With Sodium Peroxide:
warm reddish brown, medium density
Example 15
[0120] TABLE-US-00004 Solution A: Iron (II) Perchlorate 4 grams and
Silver Sulfate 0.1 grams in 200 ml H.sub.2O With Hydrogen Peroxide:
warm gray aged appearance, light density With Sodium Peroxide:
reddish gray aged appearance, light density
Example 16
[0121] TABLE-US-00005 Solution A: Iron (II) Chloride 2.5 grams and
Silver Sulfate 0.5 grams in 150 ml H.sub.20 With Hydrogen Peroxide:
minimal reaction With Sodium Peroxide: gray-black with silvery
sheen, dark density With Sodium Peroxide warmer gray-black with
reddish and Hydrogen Peroxide tinge, dark density mixed
together:
Example 17
[0122] TABLE-US-00006 Solution A: Iron (II) Perchlorate 1 gram in
200 ml H.sub.2O With Hydrogen Peroxide: gray brown aged appearance,
light density With Sodium Peroxide: orange brown aged appearance,
light density
Example 18
[0123] TABLE-US-00007 Solution A: Iron (II) Chloride 1 gram in 200
ml H.sub.2O With Hydrogen Peroxide: gray brown aged appearance,
light to medium density With Sodium Peroxide: richer brown aged
appearance, light to medium density
Example 19
[0124] TABLE-US-00008 Solution A: Iron (II) Chloride 1 gram in 400
ml H.sub.2O With Hydrogen Peroxide: gray brown aged appearance,
light density With Sodium Peroxide: warm brown aged appearance,
light density
Example 20
[0125] TABLE-US-00009 Solution A: Magnesium Nitrate 1 gram in 250
ml H.sub.2O With Hydrogen Peroxide: minimal result With Sodium
Peroxide: yellow appearance, medium density
Example 21
[0126] TABLE-US-00010 Solution A: Cerium Nitrate 1 gram in 250 ml
H.sub.2O With Hydrogen Peroxide: minimal result With Sodium
Peroxide: yellow appearance, medium density
In all of the examples below the hydrogen peroxide is in a 15%
solution and the Sodium Peroxide is made with 2 grams diluted in
one liter H.sub.2O.
Example 22
[0127] Silver Perchlorate: 1.5 grams per liter H.sub.2O
[0128] Result on concrete:
[0129] With Hydrogen Peroxide: no effect
[0130] With Sodium Peroxide: gun metal gray to black
Example 23
[0131] Iron (II) Chloride:; 2 grams per liter H.sub.2O
[0132] result with cotton cloth:
[0133] With Hydrogen Peroxide: light gray
[0134] With Sodium Peroxide: orange brown
Example 24
[0135] Iron (II) Chloride: 2 grams per liter H.sub.2O
[0136] result on pale unfinished leather:
[0137] With Hydrogen Peroxide: warm golden brown
[0138] With Sodium Peroxide: grayish tan
Example 25
[0139] Iron (II) Chloride: 2 grams per liter H.sub.2O
[0140] result on paper:
[0141] With Hydrogen Peroxide: light gray
[0142] With Sodium Peroxide: rich sepia
[0143] The embodiments illustrated and discussed in this
specification are intended only to teach those skilled in the art
the best way known to the inventors to make and use the invention.
Nothing in this specification should be considered as limiting the
scope of the present invention. Modifications and variations of the
above-described embodiments of the invention are possible without
departing from the invention, as appreciated by those skilled in
the art in light of the above teachings. It is therefore to be
understood that, within the scope of the claims and their
equivalents, the invention may be practiced otherwise than as
specifically described.
* * * * *