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Description  |
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TECHNICAL FIELD
The subject invention relates to the production of flexible cellular
products formed from polyether-derived polyurethane. Polyurethane foam is
used to fabricate mattresses, cushions and thermal insulators. However,
untreated polyurethane products readily ignite when contacted with an
ignition source. The present invention is directed to treatment of such
products to inhibit flammability.
BACKGROUND ART
Polyurethane foam substrates are widely used materials. Such polymeric
substrates are ordinarily manufactured by a casting process in which a
mixture of liquid polyurethane-foam-generating reactants are deposited in
a mold. Evolution of a gas causes the reactants to foam. For some foam
formulations, the reactants themselves react to evolve sufficient gas; in
others, a blowing agent is mixed with the reactants to provide gas
evolution. Continued gas evolution causes the foam to expand and fill the
mold. The foam becomes increasingly viscous as the reactants polymerize,
ultimately curing into a polyurethane foam casting shaped by the mold.
Through the years, a number of methods for reducing flammability of
flexible cellular products have been reported. One such method involved
addition of halogen, antimony or phosphorous containing compounds to the
foam reactants prior to fabrication of a product. However, the addition of
those compounds impaired physical characteristics of the product.
Specifically, flexibility and resiliency were affected. Also, these flame
retardant compounds afforded minimal protection against flame penetration
because the product melted when contacted by a flame.
A second reported method impregates a preformed cellular material with a
flame retardant composition like an ammonium phosphate solution. This
method improved resistance to ignition, but the physical characteristics
of the impregnated product were inferior.
A third method according to Belgain Pat. No. 841,224, published Oct. 28,
1976, coats flexible polyurethane foam with a flame retardant. The coating
can comprise a carboxylated neoprene latex and a mineral hydrate, such as
alumina trihydrate. At combustion temperature, the function of the coating
is to release water and thereby cool an ignited foam surface. A carbon
char is formed during ignition.
DISCLOSURE OF THE INVENTION
The subject invention is a patentable improvement over the prior art. The
water-based impregnant of the subject invention not only imparts desirable
physical characteristics to a flexible foam, but also renders
substantially non-flammable polyether-derived polyurethane foam substrates
to which it has been applied.
Typically, the subject water-based formulation includes a carboxylated
neoprene latex and an alumina trihydrate; and it can also include
diammonium hydrogen phosphate, urea, a surfactant, a bi-metallic salt
complex and water. A typical impregnant formulation appears below;
______________________________________
Carboxylated Neoprene Latex
100 grams
Alumina Trihydrate 125 grams
Diammonium Hydrogen Phosphate
5 grams
Urea 75 grams
Surfactant 1 gram
Water As required
______________________________________
The subject formulation should have a low viscosity to facilitate
impregnation of substrates as well as a high total solid content. The
viscosity of the formulation is preferably between about 2600 centipoise
and about 5500 centipoise. The formulation can be applied to a substrate
by any conventional means like dipping, coating or spraying. Cured
impregnated foam can be laminated to other substrates. An object of the
present invention is to render polyether-derived polyurethane foam
substantially non-flammable. Another object is to form a carbon char,
having superior stability and physical strength and the release of water
to cool the substrate surface when the foam is contacted by an ignition
source. It is a further object of the invention that the impregnated foam
have a low flammability and form a minor amount of smoke and non-toxic
gases when ignited. Another object is the formation of an impregnated foam
that has an open, breathable surface and retains its physical
characteristics.
Impregnated products of the subject invention are useful in a variety of
environments. For example, breathable, yet non-flammable foam products of
the subject invention can be used in mattresses to mitigate hospital
patient bed sore problems. Similarly, the subject foams have application
in mass transit vehicles and in penal institutions where vandalism and
arson are potential hazards. The impregnating formulation of the subject
invention can also be used to impregnate fabrics as well as to control
acoustics where porosity and flammability of the product are also
important.
The novel features which are characteristic of the invention, both as to
the formulation of the impregnant and the application of that impregnant
to a porous substrate, together with further objectives and advantages
thereof, will be better understood from the following description in
connection with the examples illustrating the preferred embodiments of the
invention. However, the following description and illustrated examples are
descriptive only and not intended as a definition of the limits of the
invention.
BRIEF DESCRIPTION OF THE DRAWING
The method of carrying out the invention is diagrammatically described in
the sole FIGURE.
BEST MODE FOR CARRYING OUT THE INVENTION
The formulation referred to above comprises the subject invention along
with its method of application and products therefrom. In general, the
impregnant should be formulated so that it has a low viscosity, high total
solids content, forms a stable carbon char, and does not significiantly
affect the physical properties of a foam substrate. The formulation is
designed so that flame retardant characteristics are achieved through a
dual mechanism. One mechanism functions to release water and thereby cool
an ignited surface of an impregnated foam. Thereafter, the impregnant also
forms a thermal insulating carbon char that burns slowly and maintains the
structural integrity of the foam. At combustion temperature, the
formulation is designed to minimize the formation of smoke and preclude
the emission of toxic gases. The product of this invention is
substantially non-flammable.
An essential ingredient of the formulation is a carboxylated neoprene
latex. That ingredient can be a copolymer of chloroprene with another
organic monomer. A suitable monomer is an unsaturated carboxyl acid such
as acrylic acid or methacrylic acid. The concentration of this monomer is
between about 2% and 20% by weight of the total quantity of copolymer.
Typically, the concentration is less than or equal to 5%.
The neoprene latex polymer can be prepared by any known technique.
Typically, it is prepared by polymerization in emulsion in the presence of
a radical initiator, for example, peroxide or an organic hydroperoxide,
and with a chain linking agent such as alkyl-mercaptan or bisulphate of
dialkyl-xanthogene. Polymerization techniques are described in detail in
U.S. Pat. Nos. 3,651,037, 3,839,241, and 3,347,837 and in Belgian Pat.
Nos. 815,662 and 841,224.
A carbonization agent is included in the neoprene polymer formulation. The
agent can be any chemical composition which is not volatile at ignition
temperatures, is non-flammable or only slightly flammable, does not
increase the ignition temperatures, and has a structure which enhances the
physical characteristics of a carbon char formed during ignition. Suitable
carbonization agents are urea formaldehyde and melamine formaldehyde
resins, melamine phosphate, phthalic anhydride and pyromellitic anhydride.
Phosphate formations enhance the formation of a carbon char. A suitable
concentration of the carbonization agent is between about 5 and 15 parts
per 100 parts by weight of neoprene latex.
The other essential ingredient in the formulation is alumina trihydrate.
The particle size of the hydrate must be small enoough to give good
dispersion and have a broad particle size distribution so that the
formulation has a low dispersion viscosity. Typical alumina trihydrates
useful in the practice of the invention are 336-SP made of Solem
Industries and GHA 132 and GHA 432 made by Great Lakes Mineral Company.
Its concentration should be between about 10 and about 180 parts per 100
parts by weight of neoprene latex. Generally, the concentration of the
alumina trihydrate is dictated by the degree of flame retardancy that is
desired. If the concentration is below the lower limit of the range, only
minimal protection is afforded. Beyond the upper limit, good flame
retardance is achieved but the integrity of the foam substrate is
adversely affected. Alumina trihydrate is a unique metal hydrate because
only non-toxic combined or crystallization water is released on heating
and because it forms an inert residue, which enhances the structural
integrity of the carbon char layer.
The formulation also includes several additives which enhance the fire
retardant and physical characteristics of the formulation. Diammonium
hydrogen phosphate and urea are two such additives. The concentration of
those ingredients should be about 5 parts and about 7.5 parts by weight
per 100 parts by weight of neoprene latex, respectively.
Another additive is a magnesium-zinc salt complex like Ongard II sold by
National Lead Company. The concentration of this salt complex should be
between about 1 to about 5 parts per 100 parts of neoprene latex.
Concentrations which exceed the maximum concentration promote excessive
cross-linking in the formulation. That increased cross-linking promotes
surface cracking on impregnated foam substrates when they are in contact
with an ignition source. The overall effect is a reduction in the flame
retardant characteristics of the formulation.
Another ingredient in the formulation is a surfactant like a triethanol
amine or a 100% active non-ionic fatty acid based surfactant known as
Emmersoft 7777 and sold by Emery Industries, Inc. The surfactant permits a
reduction in the dispersion viscosity which allows an increase in the
dispersion total solids content in the formulation. The effect of this
viscosity decrease is to allow reduced amounts of water to be used and
thereby improve drying and airing rates. The concentration of the
surfactant is between about 1 to about 2 parts per 100 parts by weight of
neoprene latex.
Other additives can also and optionally be included in the formulation. For
example, fillers like BaSO.sub.4 and CaSO.sub.4 can be added. Addition of
such additives is an alternative to having them included in the foam
substrate formulation. Thus, walls of the substrate cells can be coated
with such materials. Other materials can also be included.
Because the formulation is water based, its dispersion viscosity can be
adjusted with the addition of water. The amount of water, if any, added to
the formulation is not critical; and typically, its concentration is
between about 1 and about 50 parts per 100 parts by weight of neoprene
latex. Desired viscosity is dictated by processing requirements, character
of the neoprene latex and particle size and particle size distribution of
the alumina trihydrate. Suitable viscosities of the formulation range
between about 2600 to about 5500 centipoise. Desirable viscosities are
merely those which facilitate the impregnation of a flexible foam
substrate.
The ingredients of the subject invention can be formulated in a
conventional manner. Generally, alumina trihydrate and additives are
premeasured and mixed with the neoprene latex. The neoprene latex is
generally formulated with a carbonization agent. For low dispersion
viscosity formulations, the surfactant should be added to the neoprene
latex first, followed by an aqueous solution of urea and diammonium
hydrogen phosphate, if additional water is to be used. The aqueous
solution should be added slowly to the latex with vigorous stirring to
prevent localized latex coagulation. The resulting formulation is then
applied to a flexible foam substrate, which can be laminated to another
substrate.
The impregnating formulation of the subject invention is advantageously
applied to flexible polyether-derived polyurethane foam substrates.
Polyurethane foam can be produced by the reaction of a polyester with a
diisocyanate. Such urethanes are polyester-derived polyurethanes. A
polyether can be substituted for the polyester; those urethanes are
polyether-derived polyurethanes. Desirable substrates are those which have
a uniformly open cell structure, because such a structure facilitates
impregnation. The foam substrate should selected so as to afford a medium
that has a high porosity, which permits uniform impregnation and that has
sufficient structural integrity to support the impregnant. Low porosity
foams are difficult to impregnate uniformly and, therefore, are subject to
cracking if the fire retardant agent is extremely heavy on the surface.
Polyether-derived polyurethane foam substrates are essential to the proper
practice of the subject invention. Foam substrates that facilitate
formation of a carbon char are preferred. The thickness of the substrates
are preferably equal to or greater than 3/16 inch in order to provide
sufficient flame resistance without being unduly thick so as to crack
under thermal stress.
A suitable polyether-derived polyurethane foam substrate is S2850 sold by
Reeves Brothers, Inc. S2850 is a halogenated organophosphate polyether
foam formulation having a density of 2.8 lb./ft..sup.3 and an indentation
load deflection (ILD) of 50. Another suitable polyether substrate is PS
1936 FL also sold by Reeves Brothers, Inc. PS 1936 FL is an
organohalide/antimonyoxide polyether formulation. It has a density of 1.9
lb./ft..sup.3 and an ILD of 36. Typically, the polyurethane foam density
is at least about 1.0 lb./ft..sup.3.
A foam substrate can be impregnated with the unique fire retardant
formulation of the subject invention using any conventional mechanism. One
conventional means includes placing a cellular foam on a conveyor means.
The means advances the foam past a formulation dispensing means disposed
above the foam. The dispensing means can be a reciprocating nozzle which
traverses the translating foam and applies a stream of formulation
thereon. The impregnated foam can then be passed by a skimming means that
spreads or removes the formulation to achieve a desired flame retardancy
and texture for the impregnated foam. Of course, the rate of traverse of
the dispensing nozzle and the rate of the formulation dispensed from the
nozzle can be controlled so that the desired fire retardancy of the
impregnant can be achieved without skimming.
Alternatively, the formulation can be directly sprayed on one or all sides
of a foam substrate in a uniform thickness using conventional commercial
spraying apparatus. Thereafter, the impregnated foam travels through a
conventional roller means to nip or to squeeze tightly between them the
foam so that the formulation moves deeper into the substrate. Pressure
applied by the roller means varied between 2 and 50 psi with application
levels varying from 5 to 26 oz/yd.sup.2. Then, the impregnated foam is
passed through a conventional drier at about 125.degree. F. to about
350.degree. F. for about 5 to about 10 minutes to remove moisture and to
allow partial cross-linking to occur. Consequently, the method of the
subject invention comprises depositing the impregnant on a
polyether-derived polyurethane foam substrate, impregnating and curing it,
and recovering a substantially non-flammable product.
When a flame is applied to the present impregnated foams, they do not melt
or drip, that is, do not have a tendency to spread flame, as do many known
flexible foams. Instead, because of the presence of the unique,
substantially non-flammable formulation, the impregnated product converts
to a stable cellular carbonaceous barrier. That carbon char is a good heat
insulator and prevents the impregnated product from reaching a temperature
at which it will ignite. In addition, the product is cooled by the
emission of water at relatively high temperatures that result from the
decomposition of the alumina trihydrate. Because of this, the surface of
the impregnated product in contact with a flame source may be at ignition
temperature, but the temperature beneath the surface of the carbon char
will be significantly less than that. The impregnation of the product not
only inhibits ignition, but also protects against flame penetration.
Coating urethane substrates with the subject formulation is unsuitable
because mere topical application permits surface cracks to develop. Such
ruptures allow untreated, interior portions of the substrate to ignite.
Consequently, impregnation is required. This produces a much more
rupture-resistant char on exposure to high heat flux. This characteristic
is enhanced by locating the impregnant beneath the surface of the
substrate. The closed cell nature of polyester-derived polyurethane foams
makes it difficult to achieve sufficient depth of impregnation which makes
this substrate unsuitable for use in the subject invention. Impregnated
polyester foams and surface coated polyether foams share this defect which
results in surface cracking.
EXAMPLES
The following examples illustrate the invention. A flame retardant test
procedure was used in each example. The procedure included cutting
impregnated foam into approximately 8.times.9 inch samples. The samples
are then glued with a styrene-butadiene rubber-based adhesive to a
substrate foam having identical dimensions. The thickness of the laminate
is about 1 inch. The laminate is then disposed at a 45.degree. angle above
a flame for evaluation. The flame from a Bunsen burner was adjusted to
give a six-inch height. The top of the burner was four inches below the
sample. Thus, foam was bathed in two inches of flame. Flame temperature
was in excess of 1500.degree. F. Evaluation was stopped after 400 seconds
if no fire or burn through occurred. The following observations were
considered:
1. Time for the flame to cease climbing the sample's surface, i.e., for the
foam sample to cease "fighting" or "rebuffing" the flame.
2. Development of cracks in the sample's surface which facilitates the
spread of a fire.
3. Smoke formation.
4. Time for foam sample to ignite.
5. Time to burn through the sample.
6. Difficulty in extinguishing ignited sample.
7. Condition of sample after fire retardant evaluation.
EXPERIMENT I
The flame retardant characteristics of several different foams were
evaluated using the flame retardant test procedure. One-quarter inch thick
unimpregnated foams were laminated to three-quarter inch S2850 foam sold
by Reeves Brothers, Inc. A Milligan No. 13-673A adhesive comprising
1,1,1-trichloroethene with a 45% solids content was used to form the
laminate. The results are reported in Table I.
TABLE I
______________________________________
Unimpregnated Burn Through Time
1/4 Inch Substrate
(Seconds) Observations
______________________________________
Organo Halide Phos-
phate Polyether Foam:
1.5 lb/ft.sup.3 density;
29 Flaming Drops
24 ILD (S1524 sold by
Reeves Brothers, Inc.)
Organo Halide Phos-
phate Polyether Foam:
a 1.5 lb/ft.sup.3 density:
27 Flaming Drops
23 ILD (S1523 sold by
Reeves Brothers, Inc.)
Organo Halide Phos-
phate Polyether Foam:
a 1.5 lb/ft.sup.3 density;
26 Flaming Drops
23 ILD (CS1523 sold by
Reeves Brothers, Inc.)
Organo Halide Phos-
phate Polyether Foam:
a 2.8 lb/ft.sup.3 density;
24 Flaming Drops
a 50 ILD (S2850 sold by
Reeves Brothers, Inc.)
Organo Halide Phos-
phate Polyether Foam:
a 2.8 lb/ft.sup.3 density;
27 Flaming Drops
a 50 ILD (CS2850 sold by
Reeves Brothers, Inc.)
Organo Halide/Anti-
mony Oxide Polyether
Foam: a 1.9 lb/ft.sup.3
35 Flaming Drops
density; a 36 ILD
(PS1936 FL sold by
Reeves Brothers, Inc.)
______________________________________
EXPERIMENT II
One-quarter inch samples of polyether foams S2850 and PS1936 FL sold by
Reeves Brothers, Inc., were impregnated with a copolymer emulsion of
water-based carboxylated chloroprene and methlacrylic acid latex (Neoprene
Latex 102 manufactured by E. I. DuPont). The impregnant was not diluted
with water and cured in an oven for about 5 minutes at 150.degree. C. Each
polyether foam was impregnated as follows:
30 ounces per square yard,
20 ounces per square yard,
15 ounces per square yard, and
12 ounces per square yard.
The impregnated samples were then glued to 3/4 inch S2850 polyether foam.
Fire retardant characteristics were evaluated. The data appears in Table
II.
TABLE II
______________________________________
Amount
1/4 Inch
of Impregnant
Impreg-
Equi- Concentra-
Burn
nated valent tion Through
Substrate
Weight* (oz/yd.sup.2)
Time (Secs.)
Observations
______________________________________
S2850 28.76 7.19 113 Flash fire;
Difficult to
Extinguish
PS1936 29.56 7.39 .about.50
Flash fire;
FL Difficult to
Extinguish
S2850 20.1 5.02 77 Flash fire; Easy
to Extinguish
PS1936 25.2 6.31 49 Flash fire; Easy
FL to Extinguish
S2850 14.1 3.53 165 Rapid fire; Easy
to Extinguish
PS1936 15.7 3.93 335 Rapid surface
FL fire; Easy to
Extinguish
S2850 12.8 3.20 122 Surface fire
PS1936 15.4 3.86 45 Surface fire;
FL Easy to Extin-
guish
______________________________________
*Equivalent weight based on optimum formulation of impregnant.
EXPERIMENT III
Experiment II was repeated except that the samples were impregnated with
the following formulation:
______________________________________
Carboxylated Neoprene Latex
(Neoprene Latex 102 sold by
E. I. Dupont) 100 grams
Alumina Trihydrate (336 SP
sold by Solem Industries)
125 grams
______________________________________
The impregnated sample was cured in an oven for about five minutes at
150.degree. C. The results of the fire retardancy evaluation appear in
Table III.
TABLE III
______________________________________
1/4 Inch
Amount of Impregnant
Impreg-
Equiv- Concentra-
Burn
nated valent tion Through
Substrate
Weight* (oz/yd.sup.2)
Time (Secs.)
Observations
______________________________________
S2850 29.7 27.40 >400 Surface crack
at 245 sec.
PS1936 29.7 27.40 >400 Surface crack
FL at 75 sec.
S2850 17.4 16.0 187 Surface crack
at 65 sec.
PS1936 20.9 19.26 >400 surface crack
FL at 66 sec.
S2850 15.2 14.04 164 Surface crack
at 75 sec.
PS1936 15.8 14.58 >400 Surface crack
FL at 50 sec.
S2850 12.5 11.53 .about.347
Crack at 200
sec. Readily
ignited.
PS1936 13.1 12.07 >400 No fire; crack
FL at 368 sec.
______________________________________
*Equivalent weight based on optimum latex formulation of impregnant.
EXPERIMENT IV
Once again, Experiment II was repeated, however, the 1/4 inch foam
substrate was impregnated with the following formulation:
______________________________________
Carboxylated Neoprene Latex
(Neoprene Latex 102 sold by
E. I. DuPont) 100 grams
Alumina Trihydrate (336 SP
sold by Solem Industries)
125 grams
Diammonium Hydrogen Phosphate
5 grams
Urea 7.5 grams
A Non-Ionic Fatty Acid Based
Surfactant (Emmersoft 7777
sold by Emery Industries, Inc.)
1 gram
Water 5 grams
______________________________________
The impregnated product was cured in an oven for 5 minutes at 150.degree.
C. The fire retardant characteristics were evaluated and appear in Table
IV.
TABLE IV
______________________________________
1/4 Inch
Impreg- Concentration
nated of Impregnant
Burns Through
Substrate
(oz/yd.sup.2)
Time (Secs.)
Observations
______________________________________
S2850 27.1 >400 Very good char;
Flame over 246
seconds
PS1936 FL
26.8 >400 Very good char;
Flame over .about.60
seconds
S2850 18.5 >400 Very good char;
Flame over 202
seconds
PS1936 FL
18.1 >400 Very good char;
Flame over 190
seconds
S2850 13.5 .about.200 Crack at 100
seconds
PS1936 FL
14.1 >400 Very good char;
Flame over 145
seconds
S2850 10.92 >400 Crack at 31
secs; Over
flame 100 secs
No fire
PS1936 FL
13.8 >400 Very good char;
Flame over 110
seconds
______________________________________
EXPERIMENT V
Experiment II was again repeated except that the complete formulation of
the subject invention was utilized to impregnate the 1/4 inch foam
substrate. The substrate was impregnated with the following formulation:
______________________________________
Carboxylated Neoprene Latex
(Neoprene Latex 102 sold by
E. I. DuPont) 100 grams
Alumina Trihydrate (336 SP
sold by Solem Industries)
125 grams
Diammonia Hydrogen Phosphate
5 grams
Urea 7.5 grams
A Non-Ionic Fatty Acid Based
Surfactant (Emmersoft 7777
sold by Emery Industries, Inc.)
1 gram
Magnesium-Zinc Salt Complex
(Ongard II sold by National
Lead Company) 1 gram
Water 6 grams
______________________________________
The impregnated product was cured for 5 minutes in an oven at 150.degree.
C. and then adhered to the 3/4 inch foam substrate. Flame retardancy
characteristics were once again evaluated. The results appear in Table V.
TABLE V
______________________________________
1/4 Inch
Impreg- Concentration
nated of Impregnant
Burn Through
Substrate
(oz/yd.sup.2)
Time (Secs.)
Observations
______________________________________
S2850 28.2 400 Over-flame 265
sec; Good char
PS1936 FL
28.4 400 Over-flame 260
sec; Good char
S2850 18.7 400 Over-flame 187
sec; Good char
PS1936 FL
18.9 400 Over-flame 20
sec; Good char
S2850 14.0 232 Crack at 50
sec.
PS1936 FL
14.2 400 Over-flame 145
sec; Very Good
char
S2850 11.2 136 Crack at 25
sec; bad fire
PS1936 FL
12.8 400 Over-flame 75
sec.
______________________________________
EXPERIMENT VI
Various polyether foams were impregnated with the formulation used in
Example V. The 1/4 inch foam substrate was cured for 5 minutes at
150.degree. C. Those substrates were glued to a 3/4 inch substrate of
S2850 foam for flame retardant evaluation. The results appear in Table VI.
TABLE VI
______________________________________
Concen-
tration
1/4 Inch of Im-
Impregnated pregnant Burn Through
Substrate (oz/yd.sup.2)
Time (Secs.)
Observations
______________________________________
Organo Halide
Phosphate Poly-
ether Foam: 2.8
lb/ft.sup.3 density;
14.58 >400 S2850 decomp.
50 ILD (CS2850 & melt thru
Sold by Reeves surface
Brothers, Inc.)
High Resiliency
Organo Halide
Phosphate Poly-
ether Foam: 2.7
14.85 >400 Excellent
.+-.0.2 lb/ft.sup.3 results
density; 33 ILD
(HR 33 sold by
Reeves Brothers,
Inc.)
Organo Halide
Phosphate Poly-
ether Foam: 1.5
14.85 >400 Very good
lb/ft.sup.3 density; char
24 ILD (1524 sold
by Reeves Brothers,
Inc.)
Organo Halide
Phosphate Poly-
ether Foam: 1.5
lb/ft.sup.3 density
14.04 >400 Very good
23 ILD (S1523 sold char
by Reeves Brothers,
Inc.)
Organo Halide
Phosphate Poly-
ether Foam: 1.5
lb/ft.sup.3 density
14.45 >400 Very good
23 ILD (CS1523 char
sold by Reeves
Brothers, Inc.)
Polyether Foam
with a filler:
2.8 lb/ft.sup.3
density; 28 ILD
14.52 >400 Very good
(H2828 sold by char
Reeves Brothers,
Inc.)
Polyether Foam:
2.8 lb/ft.sup.3 density;
24 ILD (A2824 sold
15.33 >400 Very good
by Reeves Brothers, char
Inc.)
______________________________________
EXPERIMENT VII
Substrates of S2850 foam were impregnated with the formulation of Example
V. The impregnated sample was cured for 5 minutes at 150.degree. C. and
adhered to a variety of different 3/4 inch foam backings. Flame retardant
characteristics were evaluated and those results appear in Table VII.
TABLE VII
______________________________________
Concen-
tration of
1/4 Inch
Impreg-
nated Burn
S2850 Through
Substrate Time
(oz/yd.sup.2)
3/4 Inch Foam Backing
(Secs.) Observations
______________________________________
15.94 Polyether Foam with a
196 Black smoke.
filler: 2.8 lb/ft.sup.3 Small fire at
density; 28 ILD (H2828 85 secs.
Sold by Reeves Bros., Inc.)
14.38 Organo Halide Phosphate
238 Melted at 175
Polyether Foam: 1.5 secs.
lb/ft.sup.3 density; 23 ILD
(CS1523 sold by Reeves
Brothers, Inc.)
18.26 Organo Halide Phosphate
>400 Melted
Polyether Foam: 1.5
lb/ft.sup.3 density; 23 ILD
(S1523 sold by Reeves
Brothers, Inc.)
15.05 Polyether Foam: 1.5
.about.275
Total flame.
lb/ft.sup.3 density; 24 ILD
Ignited at
(A1524 sold by Reeves 318 secs.
Brothers, Inc.)
14.92 Organo Halide Phosphate
>400 Small fire
Polyether Foam: 2.8 put out at
lb/ft.sup.3 density; 50 ILD
400 secs.
(CS2850 sold by Reeves
Brothers, Inc.)
14.79 High Resiliency Organo
400 Very good
Halide Phosphate Poly-
ether Foam: 2.7 .+-. 0.2
lb/ft.sup.3 density; 33 ILD
(HR 33 sold by Reeves
Brothers, Inc.)
______________________________________
It is not intended to limit the present invention to the specific
embodiments described above. It is recognized that other changes may be
made in the formulation specifically described herein without departing
from the scope and teachings of the present invention. It is intended to
encompass all other embodiments, alternatives and modifications consistent
with the present invention.
* * * * *
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