US 2004O151950A1

(19) United States

(75) Inventor: Larry E. Good, Lexington, SC (US) (51) Int. Cl. ............................................... B32B 9/00
(52) U.S. Cl. ... 428/703; 428/472
Correspondence Address:
Nail C. Jones (57) ABSTRACT
Nelson Mullins Riley & Scarborough LLP
Keenan Building, Third Floor The present invention is an alternative to currently employed
1330 Lady Street copper-based concrete and masonry Stains by providing
Columbia, SC 29201 (US) nickel Salts to produce a concrete Stain that demonstrates
improved characteristics over the copper-based Stains.
(73) Assignee: Specialty Concrete Products Unlike known copper-based Stains, the present nickel-based
Stains do not blacken or darken as readily as copper-based
(21) Appl. No.: 10/357,302 Stains.
US 2004/O151950 A1 Aug. 5, 2004

NICKEL-BASED CONCRETE STAIN, METHOD OF to-use format with a limited color range. These decorative
APPLYING SAME, AND STAINED CONCRETE Stains or coating compositions can be applied using conven
FIELD OF THE INVENTION
tional, low-cost techniques to exposed masonry, concrete or
like material Surfaces in order to provide an aesthetically
0001. The present invention relates to compositions uti attractive appearance to Such Surfaces. An acid-based Stain
lized to Stain concrete, masonry, rock, Stone and various gives concrete a variegated look that is unique in that no two
cementious Substrates. In particular, the present invention acid-Stained Surfaces are ever alike. They can be used to
relates to a nickel-based concrete Stain and method for create Soft, earth tone color shades on concrete Surfaces
applying a nickel-based concrete Stain to decoratively color Similar to the effects of tiles, marble and patinas. Acid
masonry, concrete, or other cementious Surfaces. Staining is ideal for interior concrete floors because they are
easy to clean and require little maintenance when properly
BACKGROUND OF THE INVENTION Sealed and waxed. Oftentimes, acid Staining is a cost effec
0002 Concrete and like materials are produced from the tive alternative to more expensive flooring materials. Such as
alkaline earth metals. Concrete is produced by mixing hardwood floors, tiles and carpet.
Portland, or Similar hydraulic cements, with Sand, gravel, 0008 Such stains are effective at enhancing the appear
and water. AS the water reacts with the cement, it forms ance of these materials without the necessity of expensive
hydrates with the various complex calcium compounds in and laborious pre-treatment, Such as cleaning and restora
the cement and the mixture then hardens into Solid material.
The various complex calcareous hydrates in the mixture are tion. One particular architectural acid-Stain includes an
iron-based composition that provides a natural patina to Such
insoluble in water but react readily with most acids. Surfaces. The use of the iron-based composition for Staining
0.003 Stains, pigments, and intrinsic additives have been results in a Stain that is easier to maintain than other paints
employed to decoratively stain concrete, masonry and other and Stains.
cementious Surfaces for Several years. The vast majority of 0009. A particular advantage of Such stains is that they
decorative Stains available and commercially known in the are permanent. AS mentioned above, when applied properly,
prior art have been composed of pigments or Stains, along Such stains and/or coatings do not wash, peel or leech off the
with Some type of applicable carrier base Such as water or applied Surfaces.
Solvent. These types of Stains are commonly used on
masonry, concrete and Similar Surfaces. For example, an 0010 Current concrete stains typically use divalent salts
antique effect is established on such surfaces by using of iron (iron chloride or iron Sulfate) to produce reddish
Suitable colors applied to Simulate the qualities and/or colors; copper salts (such as cupric chloride) to produce
overall aesthetic appearance desired. A variation of color greenish colors, and manganese Salts to produce the darker
tone may be accomplished from applications of pigmented brown or black colors. Hydrates of these salts are dissolved
washes. Such appearances are common throughout the in water and then mixed with hydrochloric acid (also known
Mediterranean regions of the world and are now widely as muriatic acid in the concrete industry). Sodium bichro
imitated architectural coatings. In the aforementioned prior mate may Sometimes be added as a color modifier to darken
art Stain applications, the colors most commonly employed the iron and manganese Stains and to turn the blue-green
are known as the earth tones, including terra cotta tints and color of cupric chloride to a lighter green shade.
others.
0011 A problem currently exists with many of the stains
0004 Conventional painting and Staining techniques may and, particularly, the copper-based Stains. The copper-based
provide a single tone or color over a masonry or like Surface. stained concrete will often develop black or brown spots
In order to arrive at an antique or washed effect, numerous after a Sealant has been applied to the Stained concrete.
applications of shaded and/or color pigments may be applied These spots are apparently dark oxides of copper formed by
until the desired effect is attained. When prior art pigments, the presence of free water that is trapped in the concrete by
Stains, and the like are conventionally applied to an exposed the applied Sealer before the concrete is Sufficiently cured.
masonry Surface, it is difficult to create an appropriate 0012 Most manufacturers recommend that concrete be
appearance.
allowed to cure at least four weeks after pouring So as to
0005 Certain new concrete compositions utilize an release the water in the concrete, either by hydration of the
intrinsic color mixed into the cement to change the perma cement or by evaporation into the atmosphere. Even when
nent color of the cement. However, in order to accomplish allowing extensive time for curing, Some copper-based
this, a coloring agent is mixed with the concrete blend. Stains will Still show dark Spots after Staining and Sealing.
While Such coloring agents function to change the color of 0013. It would be desirable to reduce the amount of
the concrete, a thorough clean-up of the applicator equip Spotting in Stained concrete. In addition, it would be desir
ment is necessary due to the presence of the coloring agent, able to be able to Stain concrete within a day or So after it is
resulting in considerable labor and expense. poured, rather than having to allow the concrete to cure for
0006. In addition, polymer-based paints, such as pig four or five weeks. It is to these and other aims that the
mented acrylic latexes, have also been used to Stain or paint present invention is directed.
concrete. However, while concrete floor paints form a pro
tective coating on the Surface of the concrete, Stains actually SUMMARY OF THE INVENTION
penetrate the Surface to produce a Superior bond that resists 0014. The present invention provides an alternative to
peeling & flaking. currently employed copper-based concrete and masonry
0007 Conventional acid-based stains have been Stains. In particular, the present invention employs nickel
employed for many years and come in a premixed, ready Salts to produce an attractive green Stain that demonstrates
US 2004/O151950 A1 Aug. 5, 2004

improved characteristics over the copper-based Stains. and nickel chloride may be employed. Other nickel-based
Unlike known copper-based Stains, the present nickel-based Salts may also be used. In one particular embodiment, one
Stains do not blacken or darken as readily as copper-based gallon of a 14% solution of nickel chloride solution may be
Stains. In fact, by employing the present nickel-based Stains, mixed with 11 fluid ounces of 20 degree Baume' hydrochlo
Staining of the concrete can occur only a few days after the ric acid So as to achieve approximately a 12:1. Volume ratio
concrete is poured. of nickel Solution to muriatic acid.
0.015 The nickel-based, acid-applied, chemical formula 0022 AS Suggested above, acid stain is not a paint or a
tions utilized in the present proceSS are enabled, through a coating agent but is rather Solution that causes a chemical
chemical reaction after application, concrete, masonry, reaction on a cementious material. Acid Stains can be applied
Stone, and like materials to be colored to greatly enhance the to any concrete, polymer overlay, or Self-leveling products
overall aesthetic appearance of the Structure. that have a cementious base, Such as cement-based interior
0016. More specifically, the invention employs a nickel or exterior floors, countertops, and walls. The Stain Solutions
based stain Solution composed of a nickel Salt Solution (Such are made with water, acid and inorganic Salts and react with
as nickel chloride, nickel nitrate, nickel acetate, or nickel minerals present in the concrete, resulting in coloring of the
COncrete.
phosphate) and muriatic acid. The ratio of nickel Salt Solu
tion to muriatic acid is roughly about 12 to 1 by Volume, but 0023 Not every concrete structure provides a suitable
other ratioS may be utilized. Surface for acid Staining. For example, a Smooth concrete
0.017. The stain is then applied to concrete or other like Surface will often yield more attractive results than an old
Surface in conventional Staining manners to create a lasting, worn one. If the concrete is contaminated, the aggregate is
aesthetically pleasing appearance. exposed, or the concrete has previously been acid etched, the
DETAILED DESCRIPTION OF THE
stain may not “take in” and will not look as desired. The
INVENTION
aggregate material in the cement does not react with the
Stain, only materials in the concrete paste do. In other
0.018 Reference now will be made to the embodiments of applications, and in particular where the Surface is textured,
the invention, one or more examples of which are set forth as in Stamped concrete or Stamped overlays, acid Staining
below. Each example is provided by way of explanation of provides depth of color, larger Selection of Styles, and a
the invention, not as a limitation of the invention. In fact, it realistic look to the Surface.
will be apparent to those skilled in the art that various 0024. In order to apply acid stains such as the present
modifications and variations can be made in this invention
without departing from the Scope or Spirit of the invention. invention, the concrete Surface should be clean and free from
For instance, features illustrated or described as part of one dirt, grease, paint, water repellants Such as Sealers, and
embodiment can be used on another embodiment to yield a curing agents. Such foreign agents may prevent the Stain
still further embodiment. Thus, it is intended that the present from penetrating and reacting. One cleaner for concrete
invention cover Such modifications and variations as come Surfaces that allows proper preparation prior to acid Staining
within the Scope of the appended claims and their equiva is triSodium phosphate-containing cleaners. In addition, it
lents. Other objects, features and aspects of the present may be desirable to chip or Scar the concrete Surfaces before
invention are disclosed in or are obvious from the following they are stained So as to create an "aged' appearance.
detailed description. It is to be understood by one of ordinary 0025. Unlike known stains, the present inventive stain
skill in the art that the present discussion is a description of can be applied to a concrete Surface before it is completely
exemplary embodiments only, and is not intended as limiting cured. Manufacturers of previously-known acid Stains typi
the broader aspects of the present invention, which broader cally recommend that the concrete Surface be cured for at
aspects are embodied in the exemplary constructions. least 14 to 28 or even more days to allow sufficient time to
0019. The present invention, which is an alternative to achieve a complete cure prior to Staining.
currently employed copper-based and other concrete and 0026. Acid stains such as the present invention can be
masonry Stains, uses nickel Salt Solutions in combination applied using known techniques. Typically, acid Staining a
with acids, Such as muriatic acid, to produce an attractive concrete Surface involves very few tools. The Stain can be
green Stain that demonstrates improved characteristics over applied with tools Such as Sprayers, brushes, and brooms. A
the copper-based Stains. Unlike known copper-based Stains, Saw with a diamond blade or a stencil Sand blaster may be
the present nickel-based Stains do not blacken or darken as used for Scoring the Surface or creating various designs in
readily as copper-based Stains. In fact, by employing the the Surface after Staining. Such tools allow one to cut in
present nickel-based Stains, Staining of the concrete can Simple designs or very Sophisticated mosaics. The manner in
occur only a day or two after the concrete is poured. which the Stain is applied will determine, to a certain extent,
0020 More specifically, the invention employs a nickel the look achieved after the application.
based stain Solution composed of a nickel Salt Solution (Such 0027 Typically, one gallon of acid stain will stain
as nickel chloride, nickel nitrate, nickel acetate, or nickel approximately 150 to 200 square feet of Surface. After
phosphate) and an acid Such as muriatic acid. The ratio of applying the acid Stain and allowing it to dry, the acid must
nickel Salt Solution to muriatic acid in one embodiment is
roughly about 12 to 1 by volume. The stain is then applied then be neutralized. This is typically done by employing a
to concrete or other like Surface in conventional Staining basic powder Such as baking Soda (typically 0.5 lbs baking
CS.
Soda/five gallons of water) or a Solution of ammonia (typi
cally one quart ammonia/five galls of water). The baking
0021 Various nickel-based salts may be used as the stain. Soda or ammonia may be applied to the Surface, brushed
For example, nickel acetate, nickel phosphate, nickel nitrate, over the Surface to ensure contact with the free acid Solu
US 2004/O151950 A1 Aug. 5, 2004

tions, and then removed by rinsing with water. The Surface, 0035. On day 1 after staining, the slab stained with the
particularly if it is a floor, may then be Sealed and or waxed conventional copper-based Stain exhibited very slight dark
to protect the Stain and add Shine and depth. ening in Spots but the Slab stained with the nickel-based Stain
exhibited no discoloration. The slabs were then placed
EXAMPLES outdoors.

0028. The following examples describe various embodi 0036. On day 2 after staining, the slab stained with the
ments of the invention. Other embodiments within the scope conventional copper-based Stain exhibited noticeably more
of the claims herein will be apparent to one skilled in the art darkening but the slab stained with the nickel-based Stain
from consideration of the Specification or practice of the continued to exhibit no discoloration.
invention as disclosed herein. It is intended that the Speci 0037. On day 6 after staining, the slab stained with the
fication, together with the examples, be considered to be conventional copper-based Stain was mostly black except
exemplary only, with the Scope and Spirit of the invention around the edges and there was no discoloration of the
being indicated by the claims which follow the examples. nickel-based Stained slab.
EXAMPLE 1. 0038. On day 10 after staining, the copper-based stained
Slab was almost entirely black except for the edges and there
0029. A concrete slab was poured on a grade from Still was no discoloration of the nickel-based Stained slab.
ready-mix concrete. The Slab was 4" thick, and measured 4
foot by 5 foot. The day after the slab was poured, half of one EXAMPLE 3
end of the Slab was stained with a nickel-based concrete
Stain (containing 1 gallon of 14% nickel chloride and 10 0039. About 40% of the smooth side of a concrete slab
was stained with the nickel-based acid Stain described above
fluid ounces of muriatic acid). The other end of the slab was in Example 1. Another approximately 40% of the Smooth
Stained with a known copper-based Stain and muriatic acid.
The copper-based Stain was made from cupric chloride. Side of the Slab was stained with a conventional copper
based (cupric chloride) acid stain and muriatic acid. The slab
0.030. After staining, the stained end slab of concrete was was stained So that an approximately 1-inch thick unstained
neutralized with ammonia and dried. The Stained portion of Strip of concrete remained between the two portions. The
the Slab was then Sealed. Stained portions were then Sealed with two coats of the Sealer
0031. The next day, the portion of the slab stained with described above in Example 2.
the copper-based Stain exhibited Slight discoloration but the 0040. Three days after staining, the copper-based stained
nickel-based Stain showed only minor, localized darkening. side exhibited several small black spots while the nickel
On day 4 after Staining, the copper-based Stain showed signs based stained side showed no discoloration. On day 7, the
of extensive black darkening while the nickel-based Stain copper-based side exhibited Several black Spots of up to
continued to exhibit only localized slight darkening. On day 0.25" in diameter while the nickel-based stained side con
4, the unstained end of the Slab was Sanded, water washed, tinued to show no discoloration. On day 10, the copper
dried, and Stained as above with the copper-based acid Stain based side had more and larger (approximately up to 0.375"
on one side and the nickelbased stain on the other. This left in diameter) black spotting while the nickel-based stained
two corners of the Slab Stained with each of the copper and side continued to show no discoloration. On day 17, the
nickel based Stains, one nickel/copper pair Stained 4 days black spots on the copper-based side continued to grow up
after the other. to 0.50" in diameter and became darker while the nickel
based Stained side continued to show no discoloration.
0032) Two days after staining the other end (day 6 after
the original staining), the latter copper-stained corner of the EXAMPLES 4-6
Slab was almost completely discolored in black. The nickel
based corner of the latter stained end of the slab showed no
discoloration. 0041 Acid stains were formed from other nickel-based
salts and all were tested for colorfastness. Each of the tested
0033. On day 27 after the staining, the both copper-based nickel-based Salts performed adequately after Sealing with
stained corners of the slab were completely black. The little or no discoloration and little or no cure time on the
portions Stained with the nickel-based Stain exhibited no concrete slab.
additional discoloration. 0042. One such stain (Example 4) was comprised of
nickel acetate having a pH of from about 4 to about 5;
EXAMPLE 2 another stain (Example 5) was comprised of nickel phos
0034. A slab of concrete was formed and stained with the phate having a pH of less than about 1; and the third Stain
nickel-based Stain described above in Example 1. Another (Example 6) was comprised of nickel nitrate having a pH of
Slab of concrete was formed and Stained on the same day from about 1 to about 4. Each of the Stains was applied in
combination with their related acids to concrete. The nitrate
with a conventional copper-based Stain and muriatic acid. was combined with nitric acid; the phosphate was combined
Both slabs were then neutralized with a solution of 10%
ammonia (5% household ammonia), dried with a space with phosphoric acid; and the acetate was combined with
acetic acid.
heater, and then sealed with two coats of conventional 30%
sealer (Chrome-SealTM 30% Solids Clear Sealer available 0043. It is to be understood by one of ordinary skill in the
from Specialty concrete Products, inc. of West Columbia, art that the present discussion is a description of exemplary
S.C.). The sealed slabs were then dried overnight with the embodiments only, and is not intended as limiting the
Space heater. broader aspects of the present invention, which broader
US 2004/O151950 A1 Aug. 5, 2004

aspects are embodied in the exemplary constructions. The b) applying an acid Stain to the Surface of Said concrete,
invention is shown by example in the appended claims. Said acid Stain comprising a nickel-based Solution and
What is claimed is: an acid;
1. An acid Stain for Staining concrete and other cemen c) spreading said acid stain on the Surface of Said Surface
tious materials, Said Stain comprising a nickel Salt. So that the desired coverage is achieved;
2. The acid Stain of claim 1 wherein Said nickel Salt is
chosen from the group consisting of nickel chloride, nickel d) drying Said acid-stained material Surface to result in an
acetate, nickel phosphate, and nickel nitrate. acid-Stained concrete or cementious Surface.
3. The acid Stain of claim 1 further comprising muriatic 8. The method of claim 7 further comprising applying a
acid.
4. The acid Stain of claim 3 wherein Said Stain comprises Sealer to the material Surface after applying the acid Stain.
nickel chloride and muriatic acid. 9. The method of claim 7 wherein said nickel-based
5. An acid Stain for Staining concrete and other cemen Solution comprising a nickel Salt chosen from the group
tious materials, Said Stain consisting essentially of a nickel consisting of nickel phosphate, nickel acetate, nickel chlo
Salt and an acid. ride, and nickel nitrate.
6. The acid stain of claim 5 wherein said nickel Salt is 10. A concrete material having a nickelbased acid Stained
chosen from the group consisting of nickel chloride, nickel Surface.
acetate, nickel phosphate, and nickel nitrate and Said acid is 11. The concrete material of claim 10 wherein said
muriatic acid. material has been acid Stained with a nickel-based Solution
7. A method of Staining concrete and other cementious comprising a nickel Salt chosen from the group consisting of
material comprising the Steps of: nickel phosphate, nickel acetate, nickel chloride, and nickel
a) ensuring that the Surface of Said material is free from nitrate.
dust, oil, and other contaminants that would affect Stain
bonding,