Decorative noncombustible coatings and methods of making the same

A decorative noncombustible coating for application to combustible materials. The noncombustible coating includes monoaluminum phosphate; an inert coloring material such as titanium dioxide; phosphoric acid; a surfactant solution; and water in an amount sufficient so that the resultant coating has a surface tension of at least about 60, but not in excess of about 80 dynes per centimeter.

BACKGROUND OF THE INVENTION 
The present invention is directed to noncombustible decorative coatings and 
methods of making them. In particular, the invention is directed to a 
composition which can be used as a decorative coating for walls, ceilings, 
floors and other supported, generally non-flexible furnishings to enhance 
their fire resistance and aesthetic value. The invention is particularly 
advantageous in flame retardant systems where the coating itself must be 
totally noncombustible. 
On average, about 25 people per day in the United States die in fires. If 
trends continue, some 7,500 people will die in fires in the U.S. in 1983, 
and four times that number will be injured. That fire death rate per 
capita is almost twice the international average, and is surpassed only by 
Canada. As for fire incidence, the U.S. rate per capita is the highest in 
the world. 
Because of stringent codes, most public buildings are made largely of 
noncombustible materials like concrete, glass, and metal. Thus, the major 
fire hazard is not the structure itself, but its furnishings and interior 
fixtures, i.e. walls, ceilings and services of the building, i.e. 
plumbing, electrical wiring and air conditioning. Often these items are 
made of combustible materials, increasing the fuel load of the buildings. 
It therefore is desireable to retard flame spread or prevent it entirely 
to decrease the fire hazards. 
Also of particular consequence is the increasing use of synthetic polymers 
to replace wood and other natural materials. Most of the heats of 
combustion of synthetic polymers are much higher than those for natural 
materials. Once synthetic polymers ignite, the heat produced is greater 
than that from natural materials. It is then probable that a fire will 
develop faster and be even more life-threatening. Thus, it is necessary to 
decrease the ignitability and the rate of heat release of these 
combustible materials, preferably eliminating these factors completely. 
According to the Center for Fire Research, the federal government's 
principal organization for conducting research in laboratories or fires, 
and a part of the National Bureau of Standards, 80% of fire deaths are due 
to the inhalation of smoke or hot gases and are not the result of burns. 
Toxic gases commonly found in fires include acrolein, hydrogen cyanide, 
and hydrogen chloride. These gases can be produced by certain natural 
materials, but hydrogen cyanide and hydrogen chloride, in particular are 
produced much more abundantly by many synthetic polymers than by wood. The 
smoke and gases accumulate near the ceiling of a room until the gases 
become hot enough to burn themselves. This phenomenon, called flashover, 
makes the fire spread furiously to all combustible objects in the room. 
Thus, it has become increasingly important that any flame-retardant system 
lower the rate and extent of smoke generation. 
As is clear from these alarming statistics, fire retardant systems in the 
prior art have not been effective in combating the hazards of fire. The 
present invention, however, overcomes many of the problems of dealing with 
fire hazards as discussed herein. 
Accordingly, an important object of the present invention is to provide a 
coating for furnishings and building fixtures which is totally 
noncombustible and eliminates flame spread. 
A further object of the present invention is to provide a noncombustible 
coating which lowers or eliminates the ignitability of the coated 
material. 
A still further object of the present invention is to provide a 
noncombustible coating which decreases the rate of heat release of the 
coated material. 
Another object of the present invention is to provide a noncombustible 
coating which lowers or eliminates the rate and extent of smoke generation 
from the coated material. 
Yet another object of the invention is to provide a noncombustible coating 
which is decorative and enhances the aesthetic value of the coated 
material. 
A further object of the invention is to provide a noncombustible coating 
which is inexpensive to produce and easy to apply to furnishings and 
building fixtures. 
The foregoing and other objects and advantages will appear from the 
following description of examples of the invention. 
SUMMARY OF THE INVENTION 
Briefly, in accordance with the present invention, there is provided a 
decorative noncombustible coating for furnishings and building fixtures 
which includes by weight at least about 25 parts, but not in excess of 
about 60 parts, of monoaluminum phosphate; at least about 35 parts, but 
not in excess of about 40 parts, of an inert coloring, such as titanium 
dioxide; at least about 1 part, but not in excess of about 3 parts, of 
phosphoric acid; and a surfactant solution and water in an amount 
sufficient so that the resulting coating has a surface tension of at least 
about 60, but not in excess of about 80 dynes per centimeter. 
A method of making a decorative noncombustible coating of this type 
includes the step of mixing together the amounts of monoaluminum 
phosphate, phosphoric acid and a partial amount of the water sufficient to 
form a solution of these materials. The surfactant solution is added to 
this mixture. The method includes wetting the amount of titanium dioxide 
with an amount of water sufficient to wet the titanium dioxide. The wetted 
titanium dioxide then is added to the first mixture with sufficient 
stirring to make a uniform coating mixture. The invention, together with 
further objects and advantages thereof, can best be understood with 
reference to the following specification, taken in connection with the 
accompanying claims.

DETAILED DESCRIPTION OF THE INVENTION 
Broadly stated, the present invention is directed to a composition for use 
as a decorative noncombustible coating for use on non-flexible furnishings 
and building fixtures. Five main components make up the coating. 
The first component is monoaluminum phosphate. The purity of the component 
is not critical to the invention. Several commercial grades of 
monoaluminum phosphate are available. The component, however, could be 
made by reacting stoichiometric amounts of a 60% solution of aluminum 
sulfate Al(SO.sub.4).sub.3 and a 60% solution of monosodium phosphate 
NaH.sub.2 PO.sub.4 H.sub.2 O. The amount of the monoaluminum phosphate 
incorporated into the coating is at least about 25 parts, but not in 
excess of about 60 parts, by weight. In the preferred embodiment, the 
monoaluminum phosphate is present in an amount of about 57 parts by 
weight. 
A second component of the coating is an inert non-combustible coloring 
material such as clay or titanium dioxide. The purity of the titanium 
dioxide is not critical to the invention. Although the rutile form of 
titanium dioxide is used in the examples below, other forms also may be 
used. When the titanium dioxide is incorporated into the coating, the 
amount present is at least about 35 parts, but not in excess of about 40 
parts, by weight. In the preferred embodiment, the titanium dioxide is 
present in an amount of about 39 parts by weight. 
The third component of the coating is phosphoric acid. The examples listed 
below use an 85% concentration of phosphoric acid. Other concentrations of 
phosphoric acid may be used in the present invention by adjusting the 
amounts of the other components in the coating. The phosphoric acid is 
present in the coating in an amount of at least 1 part, but not in excess 
of about 3 parts by weight. In the preferred embodiment, the phosphoric 
acid is present in an amount of 2 parts by weight. 
The fourth component of the coating is a surfactant solution. The 
surfactant solution in the present invention adjusts the surface tension 
of the coating. Suurface tension is defined as the attractive force 
exerted by the molecules below the surface upon those at the surface/air 
interface, often measured in dynes per centimeter. It is important that 
the coating maintain certain characteristics such as viscosity and 
spreadability so that it can be easily applied to the surfaces of 
combustible materials. Furthermore, the coating should cover the 
combustible material completely, and preferably, also be uniform. The 
amount of the surfactant solution present in the coating should be 
sufficient so that the surface tension of the coating be at least about 
60, but not in excess of 80 dynes/cm. The present invention contemplates 
the use of any suitable surfactant, but nonylphenol is preferred. 
It is generally preferred that the surfactant solution be present in an 
amount less than about 3 parts by weight. One such surfactant preferably 
used is nonylphenol, a technical grade mixture of nonylakylphenols as 
described at entry 6521 on page 957 of the Tenth Edition of the Merck 
Index. When nonylphenol is used as the surfactant, it may be used in an 
amount less than 1 part, and preferably is present in an amount of about 
0.2 parts. 
The surfactant solution also may include an alcohol for coupling with the 
surfactant. When nonylphenol is used as the surfactant, isopropyl alcohol 
is preferred. The amount of the isopropyl alcohol present is usually less 
than about 2 parts, or preferably, is present in an amount of about 1.7 
parts by weight. The present invention, however, contemplates the use of 
other alcohols which perform this function. 
The fifth component is water, but its purity or type is not critical to the 
invention. Water is used in the mixing of the monoaluminum phosphate and 
phosphoric acid solution. Water also is used to wet the titanium dioxide 
so that it may be added to this solution. The present invention includes 
embodiments where the amount of water is sufficient so that the resulting 
coating has a surface tension of at least about 60, but not in excess of 
80 dynes per centimeter. The coatings contemplated herein also may include 
water present in an amount of at least 50 parts, but not in excess of 
about 70 parts, by weight. In the preferred embodiment, water is present 
in an amount of about 61 parts by weight. 
A method of making the above coatings includes mixing together the amounts 
of monoaluminum phosphate, phosphoric acid, and a partial amount of the 
water so that a solution of these amounts is formed. This mixture may be 
stirred and heated in order to assure that the monoaluminum phosphate has 
dissolved to give a uniform base solution. The surfactant solution may be 
simultaneously or successively added to this base solution. 
The method includes wetting the amounts of titanium dioxide or other inert 
coloring material with a sufficient amount of water to aid in the 
subsequent combining of this wetted titanium dioxide in the previously 
described base solution. The mixture should be sufficiently stirred to 
make a uniform coating mixture. The surface tension of the coating mixture 
may then be adjusted so as to produce the desired flow characteristics. 
The sequence of these steps is not critical. 
The method may further include de-gassing or de-bubbling the coating 
mixture so as to prevent gelling. This may be accomplished by subjecting 
the coating mixture to a vacuum. The coating mixture then is available for 
packaging. 
The decorative noncombustible coatings of the present invention are used by 
their application to the surfaces of the combustible material. A number of 
conventional techniques may be used to apply the coating such as by 
brushing, spraying, etc. The coatings of the present invention have 
paint-like flow characteristics and dry or harden like other paints, the 
time being dependent upon ambient conditions. 
Having described the invention in general terms, the following example is 
set forth to more fully illustrate a preferred embodiment of the 
invention. This example, however, is not meant to be limiting. It is 
possible to produce still other embodiments without departing from the 
inventive concept herein disclosed. 
EXAMPLE 
A noncombustible coating of the present invention was prepared by mixing 2 
grams of 85% phosphoric acid, 41 grams of water and 57 grams of 
monoaluminum phosphate trihydrate (AlPO.sub.4 -14 3H.sub.2 O) together to 
formulate a base solution. This base solution was heated to dissolve the 
monoaluminum phosphate and allowed to cool to room temperature. 
A second mixture of 0.15 grams nonylphenol and 1.65 grams isopropyl alcohol 
was prepared. This mixture was then added to the base solution and 
stirred. After clarity is restored to the resulting mixtures, 38.9 grams 
of rutile titanium dioxide wetted by 20 grams of water was added and mixed 
thoroughly in a high speed blender. If the resultant coating contained 
bubbles, these bubbles were removed under vacuum to prevent gelling. 
Other coatings were prepared as described above, only the percentage of the 
nonylphenol was changed. The surface tension of these coatings was 
measured and are presented in the following table: 
TABLE I 
______________________________________ 
Percentage by weight 
Surface Tension 
nonylphenol dynes/cm 
______________________________________ 
0.107 63.4 
0.507 68.3 
0.995 76.5 
______________________________________ 
All of these coatings were brushed onto the surface of drywall that is 
commonly used in building construction. The drywall was then exposed to an 
open flame at 500.degree. C. THe coatings did not ignite and were 
otherwise totally noncombustible. There was no flame spread on the 
drywall. A negligible amount of smoke was generated. 
The decorative noncombustible coatings made in accordance with the present 
invention are contemplated for use to prevent the combustion of otherwise 
combustible materials such as non-flexible furnishings and building 
fixtures. In particular, walls may be coated to totally eliminate flame 
spread. Being noncombustible itself, the coating acts as a barrier 
material and restricts the accessibility of oxygen for any fire starting 
on the wall. The wall or other combustible material becomes 
self-extinguishing. Applied to other combustible material, the coating of 
the present invention would lower or totally eliminate the possibility of 
the material igniting during a fire. 
With all of the advantages described herein, the noncombustible coatings of 
the present invention can be decorative and add to the aesthetic value of 
the material which it coats. This is done by adding colored pigment to the 
coatings described herein, yet none of the attendant advantages will be 
lost. 
From the above, it is seen that there has been provided a decorative 
noncombustible coating which fulfills all of the objects and advantages 
set forth above. The coatings of the present invention are more than fire 
resistant, they are totally noncombustible. The coatings can be made to be 
very decorative and enhance the aesthetic value of the material which they 
are applied to. Yet, the components of the decorative noncombustible 
coatings are inexpensive and easy to produce. 
It has been further demonstrated that the present invention provides a 
decorative noncombustible coating which eliminates flame spread and the 
ignitability of combustible materials to which they are applied. 
Furthermore, since the materials to which they are applied become 
self-extinguishing and in fact do not burn, their rate of heat release and 
smoke generation are eliminated as factors contributory as fire hazards. 
It should be understood that the present invention is not limited to the 
precise composition of the example, it being intended that the foregoing 
description of the presently preferred embodiments be regarded as an 
illustration rather than as a limitation of the present invention. It is 
the following claims, including all equivalents, which are intended to 
define the scope of the invention.