A flame retardant or fire retardant preparation can be employed with fibrous material containing either cellulosic fibers, non-absorbent fibers, or blends thereof. The preparation is formed of an aqueous solution of ammonium sulfate, a metasilicate salt serving as binder, and ammonium phosphate (MAP or DAP). An ultraviolet inhibitor is preferably included in the solution. A wetting agent promotes penetration of the solution into cellulosic fibers. An ultraviolet fluorescent agent permits non-destructive testing of articles after treatment. For increased sensitivity, the preferred fluorescent agent is a substituted 2,2' disulfonic acid sodium salt.

BACKGROUND OF THE INVENTION 
This invention relates to fire-retardant or flame retardant preparations, 
and also to articles treated with such preparations. 
There is an increasing need in industry, in public places, and in the home 
for treatment of flammable articles to render them fire resistant or flame 
resistant. This requirement applies to industrial clothing. It also 
applies to international building materials such as lumber, plywood, and 
other decorative materials in the commercial and industrial marketplace 
typically associated with hospitality, educational, and health care 
facilities. Flame proofing or flame retardancy is now being required even 
for displays and the like. Flame proofing and fire proofing is also 
desirable, if not required, for upholstered furniture, for vehicle 
interiors, and for industrial gloves and outer clothing. Flame retardancy 
is also required in some situations for mattresses and is desirable for 
paper products, wall hangings, and other flammable items. 
According to a recent study of the National Fire Protection Association, 
about two-thirds of all home, hotel, and office fires originate on 
decorative materials, i.e., upholstery, wall coverings, carpets and rugs, 
draperies, and paneling, These items are generally installed after 
construction is complete or nearly complete. In industrial and commercial 
facilities whose decorative materials are mandated to be fire resistant, 
problems can occur in that if materials, in fact, do meet fire codes on 
new constructions upon completion, there is no way to ensure or check for 
the continued effectiveness of the decorative material's fire retardancy 
during or after initial construction. Significant problems in this area of 
fire protection are first, the ability to ensure that the treatment has 
been properly applied, and second, the ability to inspect the status of 
the flame- or fire-retardant treatment at future dates. 
Because of the decorative nature of many of these materials, it is 
important also that the flame-retardant or fire-retardant treatment not 
discolor the materials or otherwise degrade their appearance. 
The conventional method of treating these articles for fire or flame 
retardancy is to apply an aqueous solution of an inorganic salt having 
fire-retardant characteristics, and then to dry the article. However, 
because these conventional treatments involve a soluble inorganic salt, 
the durability of the treatment is quite limited. This is because the salt 
dissolves or leaches out in moisture and can be washed away by laundering 
or dry cleaning, or simply by perspiration or high humidity conditions. 
Another problem of conventional treatments is that the inorganic salt 
employed as a fire-retardant can bring stiffness and/or discoloration to 
the treated article. Furthermore, because the inorganic salt can be 
somewhat toxic, the amount that can be employed for a given area of fabric 
is somewhat limited. 
It would be desirable to supply the treatment as a self-application kit, 
e.g. for use by schools, parents, theater groups, etc. This would provide 
a safe and simple means for Such a self-application kit would, of course, 
facilitate the treatment in place of existing drapes, carpeting, etc., 
without requiring their removal and reinstallation. 
Another problem with previously-proposed flame- or fire-retardant 
treatments is their incompatibility with synthetic, high-polymer content 
fiber products. This is a problem derived from the use of water soluble 
inorganic salts, which have little if any tendency to bond to the surface 
of they synthetic organic polymer fibers. 
A further problem is that with a generally colorless and textureless 
treatment, the untreated product appears the same as the treated product. 
Accordingly, it would be extremely desirable to provide means to detect 
whether an item has been treated, or whether a previous treatment is still 
effective. Destructive testing, i.e., applying an open flame to the 
decorative materials, is unacceptable in almost all instances. 
One proposed solution that has met generally with success is described in 
U.S. Pat. No. 4,824,483. This involves a treatment that can be applied 
onto previously installed materials, which can be made of high-polymer 
content fibers, and which is quite durable. This patent, which involves 
the same inventor as in this improvement, also describes additives to 
enhance the penetration and persistence of the treatment and to give the 
treatment an ultraviolet detectability. 
The treatment involved in that patent is an aqueous solution of ammonium 
sulfate, a metasilicate salt serving as a binder, and an ammonium 
phosphate such as monoammonium phosphate (MAP) or diammonium phosphate 
(DAP). To this an ultraviolet inhibitor can be added, and the inhibitor 
disclosed in the patent is a substituted disulfobenzophenone, namely 
disodium 2,2'-dihydroxy 4,4-dimethoxy - 5,5-disulfobenzophenone, which is 
commercially available from BASF Wyandotte under the name UVINUL DS-49. 
This compound has fluorescent properties, and will fluoresce with a color 
ranging from orange to lime green under strong exposure to long-wavelength 
ultraviolet light. 
With such a system, a fire inspector can field-test the treated materials 
non-destructively, using an ultraviolet test lamp. This also reduces the 
need to rely solely on written documentation of treatment, as the 
effectiveness of the treatment is, or should be, visible to the inspector. 
In addition, a wetting agent can be included in the treatment to facilitate 
penetration into the fibers. In the patent, a wetting agent is disclosed 
that biogrades after treatment so that further wetting after application 
will not affect the flame retardancy. 
Unfortunately, the ultraviolet agent used in the patented formulation, 
i.e., the substituted disulfobenzophenone, does have a drawback in that 
its fluorescence is quite weak. In many cases, a zero or near-zero light 
condition (total darkness) is required to verify the presence of the 
treatment. On some materials, such as wood, the visible light is very 
difficult to see, even under ideal conditions. Moreover, under some 
conditions the ultraviolet agent does not stay in solution before 
treatment. Even though this does not affect the fire-or flame-retardancy, 
it does render the treatment impossible to verify by ultraviolet means. 
For these reasons, an improved formulation has been sought in which the 
ultraviolet agent fluoresces at a level strong enough to be detected in 
the presence of normal incident light, which will be detectable on all 
treated material, and which will reliably remain in formulation in the 
treatment until application. 
OBJECTS AND SUMMARY OF THE INVENTION 
It is an object of this invention to provide a fire- or flame-retardant 
treatment which avoids the drawbacks of the prior art, and which is 
detectable by non-destructive means. 
It is a more specific object to provide a fire- or flame retardant 
treatment which fluoresces in the presence of long wavelength ultraviolet 
light so as to be visible in ambient light. 
It is a more particular object of this invention to provide a fire- or 
flame-retardant treatment which can be applied to natural, i.e. cellulosic 
fiber products or to synthetic polymer fiber products, which is persistent 
and durable, which does not lose its flame- or fire-retardant properties 
if the treated article is dry cleaned, which will not wear off and will 
withstand numerous washings, and which does not adversely affect the 
texture or color of the treated article. 
It is yet another object of this invention to provide a flame- or 
fire-retardant treatment which can be applied to carpeting, drapery, or 
other installed articles while in place and which can be applied to 
articles formed of cellulosic fibers, or high-polymer absorbent fibers, or 
of blends of these. 
It is a further object of this invention to provide a UV-detectable flame- 
or fire-retardant treatment whose ultraviolet agent reliably remains in 
formulation until applied to the materials treated, even when the aqueous 
solution that comprises the flame-or fire-retardant is alkaline. 
According to one aspect of this invention, a flame- or fire-retardant 
preparation is formed of an aqueous solution of ammonium sulfate, a 
metasilicate salt, such as sodium metasilicate, serving as a binder, and 
an ammonium phosphate, such as monoammonium phosphate (MAP) or diammonium 
phosphate (DAP). In one typical preferred treatment, the aqueous solution 
consists essentially of about 0.9 parts sodium metasilicate, about 12.0 
parts ammonium sulfate, about 4.12 parts monoammonium phosphate, and 
sufficient water to make up 100 parts. To this an ultraviolet inhibitor is 
added. 
The dissolved ammonium sulfate penetrates into cellulosic fibers such as 
cotton, wool, cellulose, etc., and the sodium metasilicate assists the 
bonding of the ammonium sulfate both to the cellulosic fibers and also to 
non-absorbent fibers, such as nylon, acetate, polyester, polypropylene, 
etc. Monoammonium phosphate covers and bonds to the surface of the 
nonabsorbent fibers, such as nylon, polypropylene or other synthetic 
polymers, and the presence of the sodium metasilicate facilitates this. 
To increase the ability of the solution to wet cellulosic fibers, the 
solution also contains about one percent of a nonionic esterized branch 
chain alcohol ethoxylate with a phosphate base, to serve as a wetting 
agent. This loses its wetting properties after application, which inhibits 
the treatment from washing out. 
For non-destructive inspection of articles for testing both whether, and 
how well, they have been treated, the solution includes a fluorescent 
agent which emits visible light of a characteristic color when illuminated 
with long wave ultraviolet. This can be a substituted 2,2'-disulfonic acid 
salt, to it, 4,4'-bis -2-diethylamine 
-4-(2,5-disulphophenylamino)-5-triazinyl-6-aminostilbene-2, 2'-disulfonic 
acid sodium salt. This can be present in any effective amount in the range 
of 0.001% to 4% by weight of the solution. 
These materials involved in the flame- or fire-retardant treatment are 
colorless and do not degrade the visible appearance of decorative 
materials nor do they impair the touch or texture. 
The above and many other objects, features, and advantages of this 
invention will be more fully understood from the ensuing description of a 
preferred embodiment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
In the preferred embodiment of this invention, the flame- or fire-retardant 
preparation is formed as an aqueous solution of ammonium sulfate, sodium 
metasilicate, and an ammonium phosphate, preferably monoammonium phosphate 
(MAP). The ammonium sulfate, a fire-retardant soluble inorganic salt, 
penetrates into the fibers of the absorbent or "cellulosic" fibrous 
materials, and the metasilicate salt serves as a binder for the ammonium 
sulfate. The MAP attaches to the non-absorbent synthetic fibers, such as 
polyesters, polypropylene, nylons or polyamides, acetates or polyacetates, 
polyolefins, polyethylenes, and the like. The metasilicate salt affects 
some bonding of the ammonium sulfate to the non-absorbent fibers. MAP or 
DAP, in the presence of elevated temperatures, serves as an 
oxygen-starving agent. The MAP or DAP breaks down chemically at 
temperatures above about 260 degrees C., and the breakdown products starve 
oxygen from the flammable gases that emanate from heat decomposition of 
the non-absorbent fibers. This has provided an effective way of preventing 
spread of fire and flame in synthetic polymer materials. By contrast, 
conventional inorganic salts that are often used for flame- or 
fire-retardant treatment will not prevent flame spread in these synthetic 
materials. 
The effect of these ingredients is described in my earlier U.S. Pat. No. 
4,824,483, which is incorporated herein by reference. However, instead of 
the substituted disulfobenzophenone employed in the composition disclosed 
there, in the present invention a substituted 2,2'-disulfonic acid salt is 
employed as a fluorescent agent, namely 4,4'-bisdiethylamino-4-(2, 
5-disulfobenzophenone)-5-triazinyl-6-aminostilbene-2,2'-disulfonic acid 
sodium salt. 
This additive permits drapes, carpets, wall coverings, upholstery and other 
decorative materials to be tested nondestructively using a simple 
long-wave ultraviolet lamp. The testing can be carried out without 
requiring extreme darkness. The fluorescence will be observable under most 
indoor ambient light conditions, although subdued lighting is preferred. 
With this additive, the presence of the treatment is readily visible on 
wood or other cellulosic fibers, whereas the visible light was extremely 
faint when the prior compound, i.e., substituted disulfobenzophenone, was 
employed as the fluorescent agent. 
The preferred preparation has 0.9 parts of sodium metasilicate, 13.0 parts 
of ammonium sulfate, 4.12 parts of MAP, and sufficient water to make up 
100 parts. These parts are by weight. This blend represent the maximum 
amount of the chemicals that can be dissolved in water and remain in 
solution. Nevertheless, there is some trade-off between the ammonium 
sulfate and the MAP, that is if a greater amount of one of these chemicals 
is desired, the solution can accommodate it by using less of the other. 
Current experiments seem to indicate that the two together can constitute 
up to about twenty percent of the solution. Accordingly, the blend of 
ingredients can be tailored to suit a specific fabric, if the amount and 
types of fibers are known. Any combination of MAP or DAP with ammonium 
sulfate (up to this total of about twenty percent) will have good fire 
retardancy, but the optimum protection seems to be with the above 
mentioned blend. The amount of sodium metasilicate used in this example is 
sufficient for adequate bonding of the ammonium sulfate. The amount of 
this ingredient is preferably limited to keep toxicity at a minimum and to 
keep alkalinity low. 
An ultraviolet inhibitor, of commercial grade and quality, and which does 
not react with other ingredients can also be used. To increase penetration 
of the preparation into wood or other fibers, a biodegrading wetting agent 
can be employed, and one suitable agent is non-ionic esterized branch 
chain alcohol materials fluoresce to emit a characteristic bright blue 
light. This permits fire inspectors and insurance inspectors to determine 
if a particular installation meets fire code requirements. The 
effectiveness of the treatment can be quickly checked at periodic 
intervals. 
The treatment can be applied by spraying the aqueous solution onto the 
material, or by dipping the material into the solution. The water is then 
allowed to evaporate from the sprayed or dipped material. Evaporation of 
the water can be accelerated by application of heat or dry air. 
Due to the binding effect of the sodium metasilicate and the natural 
bonding characteristics of the MAP, this fire- or flame-retardant 
treatment has been found to be exceptionally durable and is not noticeably 
diminished, even by ten or more cycles of laundering or dry cleaning. The 
treatment is considered permanent. 
The flame- or fire-retardant preparation of this invention can be applied 
easily, either to new or to previously installed carpeting, draperies, 
upholstery, wall coverings, or other decorative materials. Application can 
involve simple spraying onto the carpeting, draperies, or other material, 
and permitting the treated material to dry. Removal of existing carpeting 
and reinstallation of treated carpeting in unnecessary. The preparation 
lends itself to use in self-application kits, namely a container of the 
preparation, a sprayer, a sheet of simple instructions and a small, 
hand-held UV lamp or light gun for testing. By following the simple 
instructions described ethoxylate, which retains its properties over a 
wide range of pH. 
For highly improved ultraviolet detectability, an ultraviolet fluorescent 
agent is included in the amount of about 0.04 weight percent. In the 
preferred mode, this agent is a sodium salt of a substituted 
2,2'disulfonic acid, namely 
4,4'-bis-2-diethylamino-4-(2,5-disulfobenzophenone)-5-triazinyl-6-amino-st 
ilbene-2,2'-disulfonic acid, sodium salt. This compound in solid form is a 
light yellow powder, but when dissolved is clear. The compound has an 
absorption maximum at 349 nm (longwavelength ultraviolet) and an emission 
fluorescence maximum at 438 nm (blue). The compound is soluble in water 
and retains its solubility in somewhat alkaline conditions. This compound 
is sometimes employed in photographic chemistry as an ultraviolet 
inhibitor for protection of color film. As far as can be learned, it is 
rarely or never used outside of that field, or where it is likely to be 
exposed to air and light over extended periods of time. The compound has 
the following formula: y 
##STR1## 
Treated materials can be tested using an ultraviolet lamp producing 
sufficient light at or near about 349 nm. The treated above, school 
custodial personnel, parents, theater groups, or others without special 
training can apply this fire- or flame-retardant treatment to fabrics or 
other fibrous products. The treatment can also be applied to display 
items, paper, wallpaper and building materials. 
In the above embodiment, water is employed as the vehicle for the other 
ingredients, water being a generally safe, non-toxic carrier. However, in 
industrial applications where high-speed drying is important, an organic 
carrier can be used, or an accelerator can be added to the solution. The 
substitute carrier or accelerator should be inert with respect to the 
fibers of the materials to be treated. 
The wetting agent, e.g. non-ionic esterized branch chain alcohol 
ethoxylate, also serves to hold the substituted 2,2'-disulfonic acid salt 
in solution, even in the presence of a high alkalinity from the other 
ingredients. This counters the tendency of disulfonic acid salts to 
precipitate out under high pH conditions. The ethoxylates bond the basic 
ingredients and the alkaline fluorescent compound to allow that compound 
to be accepted by the aqueous solution. Once dissolved, the substituted 
disulfonic acid remains in solution. 
The substituted disulfonic acid, with its broader light absorption 
spectrum, also serves as a UV inhibitor, providing greater protection 
against sun fading or spotting. The ultraviolet fluorescence at detection 
capabilities are increased because the fluoresce is about four times 
stronger than the fluorescent compound employed in the previous U.S. Pat. 
No. 4,824,483. Also, the substituted disulfonic acid has a number of 
absorption peaks in both the long and short wavelength portions of the 
ultraviolet spectrum. These can be combined for enhanced identification 
characteristics. 
While a particular embodiment has been described in detail hereinabove, it 
should be recognized that this invention is not limited to that precise 
embodiment, and many modifications and variations would present themselves 
to those skilled in the art without departure from the scope and spirit of 
this invention as defined in the appended claims.