Note: Descriptions are shown in the official language in which they were submitted.
~ tlon
1. Field of the Invention
This invention rPlates to R smoke suppressed rigid
polyurethane oam composition. More specifically, this
inven~ion relates to the addition o~ organic sulfur-containing
metal compounds to rigid polyurethane foam composition5 to
reduce the smoke generated on burning the resulting foams.
2. Description of the Prior Art
Rigid foams are becoming increasingly important as an
insulatlon material in construction of new buildings to reduce
energy losses. At the same time, building code agencies are
requiring lower levels of smoke to be generated when foam
burns in order to make the exits easily observable to facili-
tate access by firemen and the escape of occupants.
Prior to the instant inventlon polyurethane foams
could be smoke suppressed by using sulfur containing compounds
such as elemental sulfur or certan organo-sulfur compounds
such AS di-t-butyl pol~sul~ide and ethylene trithiocarbonate.
The use of these materials is illustrated in U.S. Patent Nos.
Z0 3,542,701, 3,876,568, and 3,933,694. These organosulfur
compounds have the disadvantage of either being too volatile
or imparting an objectionable odor during processing. Poly-
urethane foam containing these pxior art sulfur compounds
still produced substantial amounts of smoke.
The compounds used in the rigid foam compositions o
the present invention overcome the disadvantages of the prior
art because they substantially reduce the amount of smoke
produced from burning polyurethane. This has been demonstrat-
ed in the Examples inra.
St,atement of the Invent.ion
The present invention is directed to a smok~ suppressed
rigid polyurethane foam prepared from a reaction mi.xture which
comprises a smoke suppresslng amount of a compound selectéd
from the group consisting of:
S
~(R~2N-~-S~n~, ~S-Rl-S~M,
_ _ .
L~ c ~ v ¦ I n
N N -- _ _
~ \ S / M, and -S ~ N \ S~
N~ ~N M
S
_ n
wherein:
R is a lower al~yl of 1 to 5 carbons;
Rl is a cycloalkyl of 3-10 carbons or an alkyl of 2-10
carbons;
n is an integer equal to the valence of M; and
X is selected from S/ O or N~I.
M ls selected from the group consisting of copper, zinc,
aluminum, tin, antimony, bismuth, vanadium, chromium, molybdenum,
manganese, lron, cobalt, and nickel.
Detailed De cri~tion of the Invention
-
The present invention is directed to a smoke suppressed,
rigld polyurethane foam. Generally, polyurethanes are prepared
by the reaction of toluene dii~ocyanate or polymethylene
polyphenylisocyanate or mlxture thereof with polyfunctional
-- 2 --
hydroxy compounds. Some typical e~amples o~ rigid polyurethane
foams are described ln E~ N. Doyle "The Development and Use of
Polyurathane Products", McGraw-Hill Book Co., New York, 1971 and
in W.CO Kuryla and A~J. Papa, "Flame Retardancy o~ Polymeric
Materials", Volume 3, Marcel Dekker, Inc., New York, 1975.
The xigid polyurethane xesins of this invention may also con-
tain flame retardants such as chloroethyl phosphates, phos~
phorous-nitrogen compounds, and brominated or chlorinated
polyols~
The smoke suppressant additives used to prepare the
rigid polyurethane foams of this invention may be prepared by
the reaction of salts of metals selected from copper, zinc,
aluminum, tin, antimony, bismuth, vanadium, chromium, moly-
bdenum, manganese, iron, cobalt and nickel, with the sodium
salts of sulfur containing compounds selected from mercapto-
benzothiazoles, 2,5-di-mercapto-1,3~4-thiadiazoles, mercapto-
triazines, dialkyl dithiocarbamates, hydroxy thiophenols and
aliphatic dimercapto compounds having 2 to 10 carbons. These
additives are either monomeric or polyme~ic salts and can be
cyclic or linear; the~ are phy~ically mixed with the reactants
for prepari~g ~he polyurethane ~oam pre~erably in the amount
o~ 0.1 to 20 parts by weight of the formulation of reactants
(i.e., polyols, surfactants, catalysts, water, blowing agents,
flame retardant, and isocyanate) to give the polyurethane
foam.
Representative smoke suppressant additives used in
this invention are as follows:
ferrous 2-mer~aptobenzothiazole
cupric 2-mercaptobenzothiazole
zinc 2-mercaptobenzothiazole
ferrous dlmethyl dithiocarbamate
cupric dimethyl dlthiocarbamate
~ 3 ~
zinc dimethyl dithiocarbamate
ferrous dibutyl dithiocarbamat~
cupric dibutyl di.thiocarbamate
zinc dibutyl dithiocarbamate
nickelous dibutyl dithiocarbamate
antimonous dibutyl di~hiocarbamate
ferrous dimercapto-1,3,4~dithladiazole
cupric dimercapto-1,3,4-dithiadiazole
zinc dimercapto-1,3,4-dithiadiazole
ferrous salt o~ p-hydroxythiophenol
zinc salt of p-hydroxythiophenol
ferrous 2-mercaptobenzoxazole
ferrous 2-mercaptobenzimidazole
zinc salt of trimercaptotriazine
ferrous salt of l,6-dimercaptohexane
cupric salt of l,6-dimercaptohexane
cobaltous dimethyl dithiocarbamate
nickelous dimethyl dithiocarbama~e
stannous 2-mercap~obenæothiazole
In the practice of this invention, pre~erred metals
used for the smoke suppressants are iron, copper~ and zinc.
The preferred organosul~ux compounds used to prepare
the metal salts are selected from mercaptobenzothiazoles,
dimercapto-1,3,4-thiadiazoles, and dlalkyl d:lthiocarbamates.
The preferred smoke suppressants are: ferrous 2-mer-
captobenzo~hiazole, ferrous dimethyl dlthiocarbamate, ferrous
2,5-dimercapto-1,3,4-thiadiazole, cupric 2-mercapkobenzothia-
zole, cuprlc dimethyl dithiocarbamate, cupric 2,5-dimercapto-
1,3,4-thiad.iazole, æinc 2-mercaptobenzothiazole, zinc dimethyl
di~hiocarbamate, zinc dibutyl dithiocarbamate, and zinc 2,5-
dimercapto 1,3,4-thiadiazole.
The following examples illustrate the present
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.~
invention bu~ are no~ interlded to limi~ the invention thereto.
Rigid polyurethan0 foams described in the following
examples are prepared by stirring the smoke suppressant additive
with the polyol ~ollowed by addition of catalysts, surfactant,
~ater and/or blowing agent and isocyanate as described by
K.C. Fris~h and S.L. Reegan in t'Advances in Urethane Science
and Technology1', Volumes 1 to 4, Technomlc, Conn., 1971-1976.
The rigid foams are made by pouring the stirred reaction mixture
into an 8"x8"x5" box. The foam is aged for seven days, and then
cut in~o 3"x3"xl" specimens that are burned in the NBS smoke
chamber using the flaming mode in accordance with ASTM Special
Technical Publication 422 tl969) and NFPA 258 - T, "Smoke
Generated by Solld Materlals~, May, 1974. The averaye of two
or more values is reported.
Example 1 shows that a rigid polyurethane foam contain-
lng a phosphorus based flame retardant and no smoke suppressant
produces a large quantity of smoke (DmC - 355).
Examples 2-5 show that xigid polyurethane foams of the
same ~ormulaklon as Example 1 but contalning metal dialkyl-
dithiocarbAmates or zinc mercap~obenzo~hiaæole produce les5smoke than a ~oam containing prior art elemental sul-fur at the
same loadlng le~el by ~eight.
EXA~PLES 1~5
: Parts
Polyol~ Pluracol* 383 (BASF Wyandotte)(a~ 100.0
Surfactant - DC - 193* (Dow Corning)( ) 1.0
Dimethylaminoethanol (Pennwalt) 2~94
Dibutyltin Dilaurate (M & T) 0.06
Water 0.9
Blowing Agent - Isotron II* ~Pennwalt~(Cj50.0
Flame Retardant - Fyrol* 6 (Stauf~er)( )35.0
Isocyanate - PAPI* (Upjohn)( ) 182.0
Smoke Suppressant as shown below
___
(a) Sucrose - based polyol, OH number = 483, contains ~1%
phosphorus
(b) Silicone surfactant
(c) Dlethyl N,N-Bis(2-hydroxyethyl)aminomethylphosphonate
~d) Polymethylene polyphenylisocyanate, NCO equivalent = 133
Smoke ~ Smoke
D cReduction
1 None - 355 0
2 Sulfur 20 266 25
3 Ferrouq 2-mercapto- 20 216 39
benzothiazole
4 Zinc dimethyl di- 20 143 60
thiocarbamate
Zinc ~,5-dimercapto- 20 135 62
1,3,4 thiadiazole
Examples 6 - 10 show that rigid polyurethane foams
flame retarded with an organobromine compound and containing
the mekal oryano sulfur compounds of this invention produce
less smoke than a foam containing prior art elemental sulfur
at the same percent sulfur content~
*Trade Mark
~f ~
EX~PLES 6~10
. Parts
Polyol - Pluracol 383 (B~SF Wyandotte)(a) lOOoO
Surfactant - DC - 193 (Dow Corning)(b) 1.0
Dimethylaminoethanol 2.94
Dibutyltin Dilaurate 0.06
Water 0 9
Blowing Agent - Isotron II (Pennwalt)(C) 50.0
Flame Retardant - FR - 1138 (DOW)(d) 30.0
Isocyanate - PAPI (Upjohn)( ) 173~0
Smoke Suppressant as shown below
__
(a) Sucrose based polyol, OH number - 483, contalns 1%
phosphorus
~b) Silicone surfactant
~c ) F luorocarbon I ~
(d) Dibromoneopentyl glycol
(e) Polymethylene polyphen~llsoc~an~te, NCO equivalent = 133
Smoke % Smo]ce
D Reduction
~mc
6 None - 344 0
7 Sulfur ~ 6~ 23
B Ferrous dimethyl dithio- 20.1 163 53
carbamate
9 Zinc dim~thyl dithio- 20.8 179 48
carbarnate
Cupric dimethyl dithio- 20.4 194 ~4
carbamate
__ __. ____
*All present at the same percent sulfur by weight.
Examples 11-12 are presented to show the effectiveness
of zinc dimethyl dithiocarbarnate as a smoke suppre~sant for
rigld polyurethane containing a chlorinated flame retardant
(Thermolin* RF230). This metal sulfur~containing salt was
earlier shown in Example 4 to also be e~fec~ive as a smoke
*Trade Mark _ 7 _
~3~
suppressant for rlgid polyure~hane ~oam containing a phosphorus/
nitrogen flame retardant (Fyrol 6).
EXAMPLES 11-13
Parts
Polyol - Thermolin RF230 (Olin)(a)25.0
Polyol - Pluracol 383 (BASF Wyandotte)(b) 75,0
Surfactant - DC-193 (Dow Corning )(C) 1.0
Dimethylaminoetha~ol 2.94
Dibutyltin Dilaurate 0.06
Water 0-9
Blowing Agent - Isotron 11 (Pennwalt)( ) 50.0
Isocyanate - PAPI (Upjohn)(e) 132.4
Smoke Suppressant as shown below
(a) Hydroxyl~number = 365, 47% chlorine
(b) Sucrose based polyol, OEI number = 483, contains c
phosphorus
(c) Silicone surfactant
(d) Fluorocarbon 11
(e) Polymethylene polyphenylisocyanate, NCO equivalent ~ 133
Smoke % Smoke
D c Reduction
11 None - 220 0
12 Zinc dimethyl dithio- 11.6 136 38
carbamate
EXAMPLE 13
~o a rigid polyurethane recipe as described in
Examples 11-1~ is added llo 6 pph o~ zinc dibutyl dithio-
carbamate Zn L(C4H9 ~2NCS2]2 (Pennwalt~s Butyl Ziram). The
resulting rigid polyurethane foam on combustion gave smoke
~eductions on the order o~ about 38% or about the same as that
from zinc dlmethyl dithiocarbamate sho~n in Example 12.
~ .
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o~
EX~MPLE 14
2,5 dlmercapto 1,3,4-th~adiazole (50g, 0.33 mole) is
stirred in 100 ml H200 NaOH (26.7g, 0.66 mole) is slowly added
with stirring and cooling. A ZnC12 solution (45.4g, 0.33 mole
dissolved ln 300 ml H203 is added to the sodium dimercapto-
1,3,4 thiadiaæole salt solution resulting in the formation of a
white precipitate. The pre~ipitate is filtered and dried to
give a quantitative yield of zinc 2,5-dimercapto-1 t 3,4-thiadia-
zole.
Elemental and spect~oscopic analyses are consistent
with the assigned structure.
xAMæLE 15
Pre aration of Zinc Dimeth 1 Dithiocarbamate
Sodium dimethyl dithiochrbamate (75~2g, 0.66 mole) is
dissolved in 100 ml H20. A ZnC12 solution (45.4g, 0033 mole
dissolved in 300 ml H20) is added to the sodium dimethyl
dithiocarbamate solution~ Immediately, a whi~e precipitate
forms which ls ~iltered and dried to give a quantitatlve yleld
of zinc dimethyl dithiocarbamate.
Elemental an~ spectroscopic analyses are consistent
with the assigned structure as beins
S
~CH3)2N-C S ~2
ExAMæLE 16
~ _ ~ ~
Sodium dimethyl dithiocarbamate (75.2g, 0.66 mole) is
dissolved in'100 ml H20. A CuC12 solution (44.3g, 0.33 mole
dissolved in 300 ml H20) is added to the sodlum dlmethyl
dithiocarbamate solution. Immediately, a precipita~ forms
which is filtered and dried to give a ~uantitative yi~ld of
_ g
cupric dimethyl dithiocarbamate~
Elemental and speckroscopic analyse~ are consistent
with the assigned structure as being:
S
[(CH3)2N~;C-S~2Cu
~. .
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