Note: Descriptions are shown in the official language in which they were submitted.
~5~i7
BACKGROUND OF THE INVENTION
1~ Eield of the Invention
This invention relates to third degree acyclic esters of
phosphorus acid, i.e., compounds containing three P O -C
linkages.
2. Description of the Prior Art
Haloalkyl phosphates are known flame retardants, see U.S.
3,132,169; U.S. 3,287,266, U.S. 3,324,205; and U.S.
3,830,886. Commercially known haloalkyl phosphates include
- tris(bromochloroisopropyl)phosphate, trist2-chloroethyl)-
phosphate, tris(dichloropropyl)phosphate, and tris(2,3-
dibromopropyl)phosphate, see 1974-1975 Modern Plastics
Encyclopedia, McGraw-Hili Inc., New York, New York, p. 755
et seq. It has been discovered that a sub-generic group
of haloalkyl phosphates possesses increased hydrolytic and
thermal stability over other haloalkyl phosphates. This
. .
improved hydrolytic and thermal stability enables the ;~
haloalkyl phosphates of this invention to impart flame re-
tardancy of increased durability to materials treated there-
with.
SUMMARY OF THE I~VENTION
In accordance with this invention there is provided
haloalkyl phosphates of the formula
ICH2X ll/ O ~ CH2 ~ CHY ~ CHZ -R
XCH~ -C ~ CH2 - - P
CH~X ~ O - CH2 ~ CHY -CHZ - R
wherein each X is independently selected from the group
. . ~ , ,
consisting of chlorine, bromine, and hydrogen, wherein both Ys
are identical and selected from chlorine and bromine, wherein
- 2 -
~5~3~7
each Z is independently selected from chlorine and bromine, and
wherein each R is independently selected from the group consist-
ing of hydrogen, alkyl, and halogenated alkyl groups, wherein
each alkyl group contains from 1 to about 3 carbon atoms and
each halogenated group contains from 1 to about 3 halogen
substituents selected from chlorine and bromine. The halo-
; alkyl phosphates of this invention are flame retardants
possessing increased hydrolytic and thermal stability.
DESCRIP'rI~ OF THE PREFERRED EMBODIMENTS
The haloalkyl phosphates within th~ scope of this
invention are described by the following formula I:
C 2X
¦ ¦ /0 -CH2- CHY- CHZ - R
XCH2--C--CH2--O--P~
CH2X 0 -CH2- CHY- CHZ - R
(I)
wherein each X is independently selected from the group consist- -
ing of chlorine, bromine, and hydrogen, wherein both Ys are
identical and selected from chlorine and bromine, wherein each z
is independently selected from chlorine and bromine, and wherein
each R is independently selected from the group consisting of
hydrogen, alkyl, and halogenated alkyl groups, wherein each alkyl
group contains from 1 to about 3 carbon atoms and each halogena-
ted group contains from 1 to about 3 halogen substituents select-
ed from chlorine and bromine. Preferably, each R is identical
and more preferably each R is hydrogen~ It is also preferred
that Z be the same halogen as Y. Further, Y is preferably
bromine. Each X is preferably independently selected from the
group consisting of chlorine and bromine. Exemplary preferred
compounds falling within the scope of formula I include bis-
(2,3-dibromopropyl)-3-bromo-2,2-bis(bromomethyl)propyl phosphate,
bis(2,3-dibromopropyl~-3-bromo-2,2-bis(methyl)propyl phosphate,
bis(2,3-dibromopropyl)-3-chloro-bis(bromomethyl)propyl phosphate,
bis(2,3-dibromopropyl)-3-chloro-2,2-bis(chloromethyl)-propyl
phosphate, bis(2,3-dibromopropyl)-3-chloro-2,2-bis(methyl)-propyl
phosphate, and bis(2,3-dichloropropyl)-3-chloro-2,2-bis~methyl)-
propyl phosphate. For purposes of illustration only, Table I
as follows is designed to further help describe the compounds
of this invention and is neither meant nor should it be taken
to be a complete listing of all the compounds within the
scope of this invention as described by formula I.
Another preferred embodiment of this ~invention is the
following sub generic formula II:
CH 0
3 1 / 0 -CH2- CHY- CHZ -R
XCH2--C--CM2--O--P ~ ,,,
~; CH3 0- CH2- CHY- CHZ- R
~, - `';
(II)
, .
wherein ~ is chlorine or bromine and wherein Y, Z, and-R, as well
as their preferred embodiments,-are as defined above. Sub-
generic formula II is a preferred embodiment of this invention ~-
because it combines the increased hydrolytic and thermal
stability possessed by the compounds of this invention with a
relatively low viscosity to produce a flame retardant compound
which is excellent for use in polymeric systems wherein the
viscosity of the flame retardant and/or its hydrolytic and~or
thermal stability are important factors, e.g., polyurethanes.
A relatively low viscosity greatly enhances a flame retardant's
ease of handling by enabling said flame retardant to be pumped
under less severe conditions of pressure and heat. For
halogenatedflame retardants of the same thermal stability,
the difference in viscosity
~513~;7
m~ 5 ~ :
~ c.) c.) ~ ~
m m
m~
m
$ ~~ $ e~ ~ ~ m ~ ~ ~
~ _ :
Nl m m m m m ~ u a: m a: c~ m m o o c~ c) m m m
Nl m ~ m oq m v ~ m m o m m m ~ v m v m m m
~1 m m m m m c) o c) ~ o m m m u ~) m o m m m
~ m m :q m m u u c) u o m m m u c~ m u m m m
Xl m ~ m c~ m ~i u m ~ m ~ m ~ ~
Xl m ~ m u m ~ ~) m ~ u ~m ~ :r~ m ~ m '~ m
Xl m c~ c~ u m ~ u m c) u m m ~ ~ m m u o c~ m
O ~1 ~) ~ OD ~ O ~ n ~ I` co ~ o
enables the lower viscosity flame retardant to be handled at a
given viscosity while being subjected to less heat, thereby
saving energy as well as prolonging the pot life of the polymeric
composition containing said lower viscosity flame retardant
because the rate at which the flame retardant decomposes is
reduced. Further, a lower viscosity flame retardant will also
mix more rapidly with a given polymer.
The haloalkyl phosphate compounds within the scope
of this invention may be preapred according to the following
reaction scheme: ~
.'~ .
.
'~
-
I I
,N~ .
':
O~ ~ ~ ~ :
O. \ /
0 ~ ~
~ I -~
X ~ ,~ o ':
~ I ~ ,
U ~C ~ X
I
~ ~ I ~
C)--C~--C)
O H,
~, H O
':
X~ ~ X~ ~
~ I ~ N
c~--v--~ .¢ , m
o ~ o
~C ~ H
~ H t~
E~ H ~13
~35~3~7
,..;^
wherein X, Y, Z, and R are as defined above.
More particularly, the reaction of Equation A is
generally carried out by the reaction of equimolar quantities
of the desired substituted neopentyl alcohol with phosphoryl
chloride. The reaction can be carried out at a temperature
between 0 to about 150C. and preferably from about 60 to
about 120C~ using a metal salt catalyst, e.g., magnesium
oxide, titanium tetrachloride, calcium chloride, magnesium
chloride, etc. The reaction can also be carried out using an
~ 10 equimolar quantity of an organic tertiary amine base as a
j catalyst and hydrogen chloride acceptor. e.g., triethylamine,
pyridine, etc. Similarly, reaction of a metal salt of the
alcohol with phosphoryl chloride results in the desired products.
The reaction is genèrally carried out from 1 to 48 hours but
the time is dependent on the chosen temperature of the reaction.
For convenience, reaction times of 1 to 8 hours are generally
used.
, Also more particularly, ther reaction of Equation B is
generally carried out by the reaction of 2 moles of appropriately
substituted 2-haloalkanol with one mole of the appropriately
substituted neopentyl dichlorophosphate prepared by Equation A.
The reaction of Equation B can be carried out without isolation
or purification of the intermediate chlorophosphate and is
generally carried out under the same conditions as the first
reaction. The resulting phosphates are purified by washing with
dilute base to remove the acidic by-products, followed by steam
distillation to remove volatile by-products. ~he products are
dried, decolorized and filtered.
The compounds of formula 1 are useful flame retardants
in polymeric compositions selected from the group consisting of
polyurethane, including flexible and rigid foams and elastomers,
-- 7 --
polyester, both saturated and unsaturated polyester, and styrene
polymers such as polystyrene, including both crystalline and
high impact types and styrene co- and terpolymers such as styrene-
butadiene copolymer, styrene-acrylonitrile copolymer and acrylo-
nitrile-butadiene-styrene terpolymers. A further description of
above polymers applicabel to the present invention may be found
in Modern Plastics Encyclopedia, Vol. 52, No. 10~, McGraw-Hill,
IncO, New ~ork, New York (1975).
It is also contemplated that the flame retardants of
formula I will possess excellent flame retardant efficacy in
polyolefins, e.g., polypropylene and polyethylene. A detailed
description o~ polyolefin~polymers can be found in Modern
Plastics Encyclopedia, ibid.
The flame retardants of this invention may be incor-
porated into or applied onto virutally any flammablè poly-
urethane, polyester, and styrene polymeric material by tech-
niques which are standard or known to those skilled in the art.
See, for example, J. M. Lyons, "~he Chemistry and Uses of ~ire
Retardants", Wiley-Interscience, New York, NY (1970), and Z. E.
Jolles, "Bromine and Its Compounds", Academic Press, New York,
NY (1966). Depending on ths substrate and the amount of flame
retardancy desired, up to about 40 weight percent of the flame
retardant compound of formula I within the scope of this inven-
tion can be incorporated therewith. However, in most applica-
tions it is preferred to use less than 25 weight percent of said
compounds within the scope of this invention. It should be
noted that the optimum level of additive of the flame retardant
I within the scope of this invention depends upon the particu-
lar substrate being treated as well as the level of flame
retardancy desired. For example, in polyesters a flame retardant
level of from about 10 to about 3S percent by weight of the
total polymeric composition is satisfactory.
In addition to the flame retardant compounds within
the scope of this invention, the flame retardancy of a polymer
can be further enhanced through the use of so-called "synergists"
or enhancing agents which when used with the compounds of
formula I promote a cooperative effect therebetween and thus
enhance the flame retardancy of the resultant plastic composi-
tion as compared to the fiame retardancy of either one component
used separately. These "enhancing agents" comprise the oxides
and halides of groups IVA and VA of the Periodic Table, i.e.,
oxides and halides of antimony, bismuth, arsenic, tin, lead,
germanium, e.g., antimony oxychloride, antimony chloride, anti-
mony oxide, stannic oxide, stannic chloride, arsenous oxide,
arsenous chloride, and the like; and organic and inorganic com-
pounds of phosphorus, nitrogen, boron, and sulfur, e.g., tri-
phenyl phosphate, ammonium phosphate, zinc borate, thiourea,urea,
stannic sulfide, and the like and oxides and halides of titanium,
vanadium, chromium, manganese, iron, niobium, molybdenum, copper,
zinc, magnesium, e.g., titanium dioxide, titanium chloride,
vanadium pentoxide, chromic bromide, manganous oxide,molybdenum
trioxide, ammonium molybdate, and hydrates of the above, e.g.,
stannic oxide hydrate, lead hydrate, and combinations thereof.
The preferred enhancing agents are the oxides of antimony,
arsenic and bismuth. However, any compound which on decomposi-
tion, as by ignition, yields these oxides would be suitable.
Thus some organic antimonates are preferred. The enhancing
ag~nts disclosed in U.S. 3,205,196 are also suitable for use.
U.S. Patent 3,205,196, column 2, states that "Antimony
oxide
is the antimony compound that is presently preferred for use in
the present invention. ~Iowever, many antimony compounds are
suitable~ Inorganic antimony compounds include antimony sulfide,
sodium antimonite, potassium antimonite, and the likeO Many
organic antimony compounds are suitable such as the antimony
salts of organic acids and their pentavalent derivatives dis-
closed in U.S. Patent 2,996,528. Compounds of this class include
antimony butyrate, antimony valerate, antimony caproate, anti-
mony heptylate, antimony caprylate, antimony pelargonate, anti-
caprate, antimony cinnamate, antimony anisate, and their penta-
valent dihalide derivatives. Likewise, the esters of anti-
monous acids and their pentavalent derivatives disclosed in
U.S. Patent 2,993,924, such as tris(n-octyl) antimonite, tris(2-
ethylhexyl) antimoni~e, tribenzyl antimonite, tris(~-chloro-
ethyl) antimonite, tris(~-chloropropyl) antimonite, tris(~-
chlorobutyl~ antimonite and their pentavalent compounds are
the cyclic antimonites such as trimethylolpropane antimonite,
pentaerythritol antimonite, and ~lycerol antimonite. The
corresponding arsenic and bismuth compounds can also be
employed.
Without limitation, pre~erred enhancing agents
include Sb203, SbC13, SbBr3, SbI3, SbOCl, As203, As205, ZnBO4,
BaB20~.H20, 2-ZnO.3B2O3.3.5H20 and stannic oxide hydrate. The
more preferred enhancing agent is antimony trioxide.
It is also within the scope of the present invention
to employ other materials in the present invention compositions
where one so
1 0 --
8~7
desires to achieve a particular end result. Such materials
include, without limitation, adhesion promotors; antioxidants,
antistatic agents' antimicrobials, colorants; flame retardants
such as those listed on pages 665-668, Modern Plastics
Encyclopedia, ibid., (in addition to the new class of flame
retardants described herein), heat stabilizers, light
stabilizers, pigments' plasticizers, preservatives' ultra-
violet stabilizersand fillers.
In this latter category, i.e., fillers, there can be
mentioned without limitation, materials such as glass, carbon, ~
cellulosic fillers (wood flour, cork and shell flour), ~=
calcium carbonate (chalk, limestone, and precipitated calcium
carbonate); metal flakes; metallic oxides (aluminum, beryllium
oxide and magnesia); metallic powders (aluminum, bronze, lead,
stainless steel and zinc), polymers (comminuted polymers and
elastomerplastic blends), silica products (diatomaceous earth,
novaculite, quartz, sand, tripoli, fumed colloidal silica, silica
aero~el, wet process silica), silicates (asbestos, Kaolimite,
mica, nepheline syenite, talc, wollastonite, aluminum silicate
and calcium silicate); and inorganic compounds such as barium
Eerrite, barium sulfate, molybdenum disulfide and silicon
carbide.
The above mentioned material, including filler, are
more fully described in Modern Plastics Encyclopedia, ibid.,
The amount of the above described materials emp~oyed
in the present invention compositions can be any quantity
which will not substantially adversely affect the desired
results derived from the present invention compositions. Thus,
the amount used can be any amount up to that percent based
on the total weight of the composition at which said com-
position can still be cla~sified as
1 1 --
~3586;7
a plastic. In general, such amount will be from about 0/O to
about 75% and more specifically from about 1% to about 50D/o.
The following examples are provided for the purpose of
further illustration only and are not intended to be limitations
on the disclosed invention. Unless otherwise specified, all
temperatures are expressed in degrees centigrade; all weights
are expressed in grams, and all volumes are expressed in milli-
liters.
Exam~le I
Preparation of compound 1 of Table I:
A mixture o-f 650 grams of tribromoneopentyl alcohol, ~;
307 grams of phosphoryl chloride and 3 grams of magnesium oxide
was heated and stirred at 85 to 90C. for three hours. After
cooling overnight, 854 grams of dibromopropanol were added and
heated to about 85C. for six hours. After aspirating at 95C.
for 0.5 hours, the product was washed three times with an
aqueous ammonia solution having a p~l of 8 and a temperature of
50C. The volatile by-products were removed by steam distil-
lation and the product was dried, treated with Celite (trademark
for diatomaceous earth~: and Celkate (trademark for hydrated,
synthetic magnesium silicates) and filtered. A yield of 1200
grams (74%) of a ~,~riscous liquid was obtained. Analysis:
Calculate~l for CllH18Br704P: Br, 69.48. Found: Br, 69.03.
Example 2
Preparation of compound 3 of Table I:
A mixture containing 872 grams oE 3-chloro-2,2-bis-
(bromomethyl)propyl dichlorophosphate and 900 grams of 2,3-di-
bromopropanol was heated to about 85C" and allowed to react
at the temperature for about six hours. After aspirating at
95C. for 0.5 hours, the product was washed three times with
an aqueous ammonia
i~7~
f~ ' -- 12
~35~ii7
solution having a pH of 8 and a temperature of 60C. The
volatile by-products were removed by steam distillation and the
product was dried, treated with celite andcelkate, and filtered.
A yield o~ 1308 grams of a viscous liquid was obtained. Analy-
sis: Calculated for CllH16Br6C104P: Br, 63.4; C1, 4.69.
Found: Br, 62.24, Cl, 5.60.
Example 3
Compound 2 of Table I was prepared in a manner similar
to Example 2, except that 1400 g of 3-chloro-2,2-di(methyl)
propyl dichlorophosphate was reacted with 2478 g of 2,3-dibromo-
propanol to yield 2355 g of a low viscosity liquid. Analysis:
llH20Br4clo4p: Br, 53.1 Cl 5 go
Br, 51.0 Cl, 7.08.
Example 4
Compound 4 of Table I was prepared in a manner similar
to Example 2, e~cept that 234 g of tris-2,2,2-(chloromethyl)
ethyl dichlorophosphate was- reacted with 305 g of 2,3-dibromo-
propanol to yield 366 g of a viscous liquid. Analysis:
C lculate Cll 18 4 3 4
Br, 47.72, Cl 16.27.
Bis(2,3-dibromopropyl)-3-bromo-2,2-bis(methyl)propyl
phosphate and bis(2,3-dich~oropropyl)-3-chloro-2,2-bis(methyl)
propyl phosphate as well as other compounds within the scope
o~ formula I can be prepared in a manner similar to that
employed in examples 1 through 4.
.
- 13 -
Example_5
A test, hereinafter referred to as the Hydrolytic
Stability Test (HST~, has been devised to quantitatively measure
the hydrolytic stability of compounds. As applied to the comp~unds
under consideration, the HST measures the extent to which the
following reaction proceeds:
O o
H2 0 11
R10 - P - OR __~ R10 - P ~ OH + R30H
OR2 2
Equation C
wherein Rl, R2 and R3 are independently selected from halo- -
genated or unhalogenated carbon containing groups. The acid or
Hydrolytic Stability Test Number (HST number) is directly pro-
portional to a compound's hydrolytic instability.
In particular, a magnetically stirred emulsion contain-
ing 4 grams of compound 1 of Table I, 1 gram of an emulsifier
(Emcol AM2-lOC, trademark for an anionic surfactant) Witco
Chemical Corporation, Organics Division, ~ew York, New York), and
45 grams of water heated at 100C. for 44 hours. (The
emulsifier is used merely for the purpose of obtaining a uniform
emulsion of two otherwise immiscible liquids). The HST Number
of the emulsion as determined by titration with a standard
potassium hydroxide solution was 1.81.
Using the HST described in Example 5, the hydrolytic
stability of triethyl phosphate, bistbromopropyl)chloroethyl
phosphate, tris~2-chloroethyl)phosphate, tris(2,3-dibromopro- ;~
proFyl)phosphate~ and compound 2 of Table I was also determined.
The HST ~umbers for these compounds are listed in Table II
5E~7
As exemplified by bis(2,3-dibromopropyl)-3-chloro-
2,2-bis(methyl)propyl phosphate and bis(2,3-dibromopropyl)-3-
bromo~2,2-bis(bromomethyl)propyl phosphate in Table II, the
hydrolytic stability of the narrow sub-generic group of compounds
within the scope of this invention, e.g., bis(2,3-dibromopropyl-
3 bromo-2,2-bis(methyl)propyl phosphate, bis(2,3-dibromopropyl)-
3-chloro-bis(bromomethyl)propyl phosphate, bis(2,3-dibromopropyl)-
3-chloro-2,2-bis(chloromethyl)propyl phosphate, and bis(2,3-di-
chloropropyl)-3-chloro-2,2-bis(methyl)propyl phosphate, is
unob~iously better than the hydrolytic stability of close prior
art compounds. This increase in hydrolytic stability possessed
by the compounds within the scope of this invention has signifi-
cant commercial implications as is disclosed by the following
examples.
TABLE II ,
HST Number
'~ Compound (m~ KOH/g _mple)
Triethyl phosphate 17.2
'Bis(bromopropyl)chloroethyl
phosphate 9.72
Tris,(2-chloroethyl)phosphate 8.7
Tris(2,3-dibromopropyl)
phosphate 3.2
Compound 2 of Table I 1.85
Compound 1 of Table I 1.81
- 15 -
586~7
Example 6
Two flame retardant emulsions were prepared. The com-
ponents of.each emulsion and weight percent of each component
are listed in Table III.
TAsLE III
Component Emulsion X Emulsion Y
Water 60.0 60.0 :
Emulsion Concentrate 40.0 40.0
Compound 3, Table I 50.0
Bis(bromopropyl) - 50.0
chloroethyl phosphate
Solvent a 40.0 40.0 -~ :
Emulsifying Agentb 10.0 10.0
aThe solvent had a flash point of about 110F. and a .. :
boiling point of about 315F. (Hi-Sol 10, trade mark for an i. !
aromatic hydrocarbon solvent, Ashland Chemical Company,
Columbus, Ohio).
bThe emulsifying agent was an anionic blend of oil-soluble
metal sulfonates with polyoxyethylene ethers having an HLB :
value of 12.5. (Emcol N-141, trade mark for an anionic sur-
factant emulsifying agent, Witco Chemical Co., Inc., Chicago,
Illinois).
Two sets of samples of lOG% polyester fabrics (Style
~umber 755H~ 100% Spun Dacron 54 (trademark for a fibre of
polyethylene terephthalate) 36 x 32 count, 20/2 yarn size,
5.2 ounces per square yard, Testfabrics, Inc., Middlesex, New
Jersey~ were treated with the above emulsions The processes
to which the two sets of samples were subjected as well as the
data obtained from said samples are listed in Table IV.
~ 16 -
TABLE IV
Wet
Pick Up, Processing B d e
Emulsion Percent Drya Cureb AWC Count Index
........ _ .
X 72.0 X 1~,01~
X 72.~ X X 15,836
X 72.0 X X X15,2~8 30.0
Y 64.7 X 11,086
Y 64.7 X xf 2,552
Y 64.7 X X X 1,163 22.5
Control ~ 22.5
Dry: 5 minutes at 110C.
bCure: 90 ~econds at 205C.
Afterwash: 40 grams o~ soda ash and 20 grams
of Triton QS-44 detergent (Triton QS-44 is a
trademark of Rohm and Haas Company, Philadelphia, ~ -~
Pennsylvania) were used with a Kenmore 600 wash-
ing machine on a-delicate cycle, hot water
( 71C.),- and warm rinse setting. The samples
dwere tumbled dried. ;
Bromine count was obtained by the use of a
fluorescent x-ray technique. When measuring the
bromine content of identical fabric substrates
as was the case herein, the bromine count is a
relative number indicative of the bromine con-
- tent of the fabric sample. This bromine count
technique is basically a linear relation wherein
; the higher the bromine count the higher the bro-
mine content of the fabric sample.
eOxygen Index: ASTM D 2863-70.
fObservation: Tremendous fumes came out during
and after the curing.
Table IV clearly indicates that the thermal stability
of a flame retarding agent is decisive in the durability of a
given flame retardant finish. The two emulsions contrasted in
Table IV differ from each other solely in the flame retarding
agent employed. Emulsion Y which employed a prior art flame
retarding agent severely decomposed during the curing procedure,
- 17 -
as evidenced by the bromine count as well as the tremendous
amount of fumes observed during said procedure, and much of the
emulsion finish was also removed during the afterwash step.
Both of these phenomena are directly related to the relatively
poor hydrolytic and thermal stability of the prior art flame
retarding agent, bis(bromopropyl)chloroethyl phosphate, employed
in Emulsion Y. In contrast, fabrics treated with Emulsion X
containing a flame retarding agent within the scope of this ~-
invention maintained their bromine count throughout the drying,
curing, and afterwa~h procedures. This stability of Emulsion X
is due to the increased hydrolytic and thermal stability of the
compounds within the scope of this invention. The superior
oxygen index of the fabric treated with Emulsion X containing
` an exemplary flame retardant compound within the scope of this
invention over the fabric treated with Emulsion Y containing a
prior art flame retardant further exemplifies the commercial
importance of the increased hydrolytically and thermally stable
compounds within the scope of this invention.
Example 7
~ solution of 600 grams of polystyrene and 10 parts
per hundred resin (phr) of compound 3 of Table I in 2670 grams
of methylene chloride and 60 grams of hexane was prepared. To
the above solution was added 3 grams of dicumyl peroxide as a
flame retardant synergist. This mixture was poured into an alu-
minum dish and the methylene chloride was allowed to evaporate ;
in the air. Following this, the casting was steamed to produce
a crude foam. This foam was then cut into sufficient specimens
of appropriate sizes in order to subject said foam to three
tests capable of measuring the non-flammability of said foam.
The flammability tests to which the foam specimens were subject-
ed consisted of the Underwriters' Laboratories, Inc.'s UL-94
8~
Standard for Safety (UL~94), ASTM D 2863-70 Oxygen Index Test
(OI), and an ignition test (described below). The first two
of the above tests are well ~nown to those skilled in the art of
flame retardants and therefore no elaboration on or summary
of said tests is made herein. The ignition test entailed hold-
ing a foamed specimen in a vertical position and igniting said
specimen for a second or so with a micro burner. To pass this
ignition test the ignited foamed specimen upon removal of the
ignition source, should cease burning in one second or less.
10 The results obtained by subjecting the foamed specimens to the
several ~lammability tests are listed in Table V.
Additional samples of polymer were prepared in which
the amount of fire retardant was 2.5 phr and 5 phr. Still
additional samples were preparedwith the prior art compound
tris(2,3-dibromopropyl)phosphate at the 2.5, 5 and 10 phr levels.
These samples were tested in the same manner and the results
obtained are also tabulated in Table V.
TABLE V
Ignition
Flame Retardant phr OI UL-94 Test
Compound 3, Table I 1030.1 V-O Pass
do 5 28O5 V-0 Pass
do 2.5 25.5 V-2 Pass
Prior Art
Tris(2-,3-dibromo- r
propyl)phosphate10 33.0 V-0 Pass
- do 5 29.5 V-0 Pass
do 2.5 28.0 V-2 Pass
i ~.
-- 19 --
As exemplified by bis(2,3-dibromopropyl)-3-chloro,2,2-
bis(bromomethyl)propyl phosphate in Table ~, the flame retardants
of this invention, e.g., bis(2,3-dibromopropyl)-3-bromo-2,2-bist-
bromomethyl)propyl phosphate, bis(2,3-dibromopropyl) 3-bromo-2,2-
bis(methyl)propyl phosphate, bis(2,3-dibromopropyl)-3-chloro-2,2-
bis(chloromethyl)propyl phosphate, bis(2,3-dibromopropyl)-3-
chloro-2,2-bis(methyl)propyl phosphate, and bis(2,3-dichloro-
propyl)-3-chloro-2,2-bis(methyl)propyl phosphate, possess a flame
retardant efficacy comparable to that of tris(2,3-dibromopropyl)
phosphate. However, it is known that the polymerization of
styrene beads ~Jia a suspension system is a sensitive procedure.
"The stability of the suspension system depends upon the selec-
tion of the suspending agent, the degree of agitation, the
surface tension of the water, the parameter of the kettle, the
condition of the water that is charged initially to the process,
and many other factors, such as the time and the temperature
in the reaction conditions. Because of all these variables, the
stability of the suspension system is extremely important, not
just for successful operation of the suspension system without
failure and coalescence but also to guarantee an effective
beadsize distribution of the final product which emerges from
the kettles." R.B. Bishop, "Practical Polymerization for Poly-
styrene," 266, Cahners Books, Boston, Massachusetts 02116,
1971. The hydrolytic and thermal stability of flame retardant
compounds is a variable which can adversely affect the stability
of the suspension system. The higher a compound's HST Number,
the more hydrolytically unstable that compound is and the more
acidic and corrosive would be a solution or suspension contain-
ing said compound. This increase in acidity detrimentallyaffects the stability of the styrene suspension system; and
- 20 -
~5~
because of its corrosive properties, decreases the useful life
of process equipment. Therefore, the flame retardants within
the scope of this invention in~roduce into the styrene suspen-
sion system more hydrolytically stable flame retardants thereby
better assuring the stability of said styrene suspension system
while maintaining the flame retardant efficacy of prior art flame
retardantsO
The following examples exemplify other embodiments
using compounds within the scope of this invention wherein the
hydrolytic stability of said compounds makes a significant
commercial difference.
Example 8
The foam was prepared using the following basic
formulation:
Component Parts by
Weight
Polyol b 100
Silicone Glycol Surfactant 2
Trichlorofluoramethan~C 35
Polyisocyanate 135
aalkanolamine polyol, molecular weight
approximately 3500, hydroxyl number
approximately 530i Thanol R-350-X,
Jefferson Chemical Co., Houston, Texas.
bDow Corning 193, Dow Corning Corp.,
Midland, MI.
- Freon*llB, Eo I. DuPont de ~emours & Co.,
Wilmington, Del.
dPolymeric aromatic isocyanate, 31.5%
available NCO, Mondur*MRS, Mobay Chemical
Co., Pittsburgh, PA.
The polyol, surfactant, and flurocarbon blowing agent were
combined in a masterbatch based on 1000 g of polyol to mini-
mize loss of blowing agent.
The following procedure was used to prepare the
foam:
- 21 -
*Trademark
i7
1. The polyisocyanate was weighed into a tared, 10
ounce, paper cup (allowances being made for hold-
up) and the cup set aside while the remaining
ingredients were weighed out and mixed.
2. The pol~ol masterbatch was weighed out, in the
proper amount to give 100 grams of polyol, in a r
one quart, untreated, paper cup.
3. The 10 grams of Compound 3 of Table I were then
` weighed into the same one quart cup.
4~ The contents of the one quart cup were mixed at
1000 rpm for 5 seconds.
5. The polyisocyanate was then added and stirring
at 1000 rpm continued for 10 seconds.
6. The mix was poured into a 5 pound, untreated,
;` paper tub and allowed to rise.
After the foam was tack-free, and substantially cured, it was
set aside for at least seven days before cutting the foam in ;
half to observe the extent of "scorch" (discoloration) at the
center. These observations are recorded in Table VI.
Using the same procedure other foams were made at
different load levels as well as containing different flame
retardant additives. The results of these additional tests
are also reported in Table VIo
- 22 -
~5~
T~LE VI
Flame Retardant ~ Scorch OI
-
(control) -- ~one 20~5
Detected
Compound 5, Table I 10 None 23~5
Detected
do 20 None 25.5
Detected
do 30 ~one 26.5
Detected
Compound 6, Table I 10 ~one 22.5
Detected
~ do 20 None 23.5
- Detected ~:~
do 30 None 24.5
Detected
(Prior Art)
tris(2,3-dibromo- ` :
.propyl)phosphate 10 Pronounced 23.5
Scorch
do 20 Pronounced 25.5
Scorch
do 30 Pronounced 26.5.
Scorch
The presence of scorch is detrimental for basically
three reasons. First, scorch is not aesthetic in appearance
and is therefore a very undesirable property in foams whose
ultimate application necessitates their use as cuttings.
Second, industrial manufacturers fear the presence of dis-
coloration in the center of rigid polyurethane foams becauseat one time said discoloration was an indication that e~cessive
heat was being generated inside the foam during the manufactur-
ing process which could possibly result in the ingniton of
the rigid foams. Third, the presence of scorch is felt to be
an indication of the decomposition of the flarne retardant
additives which decomposition detrimentally affects the physical
:properties of the foam~
- 23 -
lOb~3S~ 7
Example 9
Type I toluene diisocyanate (hereinafter referred toas TDI) was placed in a first tank of a Martin Sweets Modern
Module No. 3A urethane foam equipment modified for six compo-
nents. Compound 2 of Table I (1 kg) was mixed with 10 kg of
Pluracol GP 3030 polyol in a second tank. (Pluracol*GP 3030
brand polyol, BASF Wyandotte, Wyandotte, MI, is a polypropylene
glycol having a molecular weight of approximately 3000 and a
hydroxyl number of approximately 56~) Stannous octoate catalyst
was placed in a third tank (T-9 brand catalyst, M & T Chemicals,
Inc., New York, NY). Into a fourth tank was placed a silicone
surfactant (L-540 brand silicone surfactant, Union Carbide
CorpO, New York, NY). A water-triethylenediamine mixture
(3/0.45) was added to a fifth tank. (Dabco*33LV brand
triethylene diamine, Houndry Process & Chemical Co., is a 33~/0
solution of triethylene diamine in dipropylene glycol.) All
the above components were simultaneously mixed using a size 3
pin type mixer at 3, 000 rmp in the following ratio:
Parts by
Component Weight
Compound 2, Table I 10
Polyol - '100 ~- -
TDI 39.3
Stannous Octoate 0.16
Silicone sur~actant 1.0
Water 3 o
Txiethylene diamine 0.45
The mixture was dropped during the mixing procedureinto a 14"
x 14" x 6" Adstrom cardboard box. After the foam came to full
height it was post cured in a forced air oven at 99 to 140C.
for 30 minutes.
*Trademark - 24 -
'7
After allowing the foam to sit ~or at least 7 days,
the foam was then subjected to ASTM D 1564 Compression Set
Method B-1971. The data obtained from this test is reported
in Table IX.
The same procedure was used to make other foams at
different load levels. Those foams were also subjected to
the Compression Set Test and the data obtained reported in
Table VII.
TABLE VII
9~/ a
Compression Set
Flame Retardant -(Parallel Rise)
phr cbt CCd
Control -- 6.98 7.75
Compound 2, Table I 10 4.23 4.70
do 20 14.9 16.5
ASTM D-1564-1971 - Compression Set Test
bMethod B
C is the compression set expressed as a
petrcent of the original thickness
CC is the compression set expressed as a
p~rcent of the original deflection,
The higher the compression set number the poorer
on the physical properties of the foam. Further, in order to
pass ASTM D-1564 Compression Set Test Method B, a foam has to
display a compression set number less than 20 percent.
Therefore, as Table VII indicates,Compound 2 of Table I passes
the ASTM test.
Other flame retardants within the scope of this
invention, e 7g~ ~ bis(2,3-dibromopropyl)-3-bromo-2,2-bis(bromo-
methyl)propyl phosphate, bis(2,3-dibromopropyl)-3-bromo-2,2-
bis(methyl)propyl phosphate, bis(2,3-dibromopropyl)-3-chloro-
bis(bromomethyl)propyl phosphate, bis(2,3-dibromopropyl)-3- --
.~
35~
chloro-2,2--bis(chloromethyl)propyl phosphate, bis(2,3-di-
bromopropyl)-3-chloro-2,2-bis(methyl)propyl phosphate, and
bis(2,3-dichloropropyl)-3-chloro-2,2-bis~methyl)propyl
phosphate, also possess excellent flame retardant efficacy
in polyurethane, polyester, and styrene polymeric compositions.
Example 10
Using the exact procedure of Example III of U.S.
3,830,886, a compound was produced which is disclosed in said
Example 3 to be 3-bromo-2,2-bis(hydroxymethyl)propyl diethyl
phosphate of the formula
1l CH2OH ~-
(CH3 CH2)2 P---OCH2 IC CH2
CH2H
The viscosity of 3-bromo-2,2-bis(hydroxymethyl)propyl diethyl
phosphate was determined at 28C. using a Brookfield Viscosi~
meter. In the same manner the viscosity of Compound 2 of
Table I was determined and the results are listed in Table
VIII. Also listed in Table VIII is the viscosity o~ tris(2,3-
dibromopropyl)phosphate, another prior art flame retardant~
TABLE VIII
Viscosity
Increase Over
Viscosity, Compound 2,
Centipoise Table I
(percent)
3-bromo-2,2-bis- 9450 497
(hydroxymethyl)propyl
` diethyl phosphate
tris(2,3-dibromopropyl)-
phosphate ' 7500 395
Compound 2, Table I 1900
- 26 -
As exemplified by bis(2,3-dibromopropyl)-3-chloro-
2,2 bis(methyl)propyl phosphate, in Table VIII, compounds within
the scope of formula II e.g., b_s(2,3-dibromopropyl)-3-bromo-
2,2 bis(methyl)propyl phosphate and bis(2,3-dichloropropyl)-3-
chloro-2,2-his(methyl)propyl phosphate, possess a viscosity
which is unobviously low in view of the prior art. This sub-
~tantial decrease in the viscosity of formula II compounds has
significant commercial implications in both flexible and rigid
polyurethane forms as well as in any polymeric system wherein
viscosity is a factor to be taken into consideration. The
relatively low viscosity of compounds within the scope of
formula II greatly enhances their ease of handling by enabling
said flame retardants to be pumped under less severe conditions
of pressure and heat. For halogenated flame retardants of the
same thermal stability, the difference in viscosity enables
the lower viscosity flame retardants within the scope of
formula II of this invention to be handled at a given viscosity
while being subjected to less heat, thereby saving energy as
well as prolonging the pot life of the polymeric composition
containing a polymer and said lower viscosity flame retardants
because the rate at which the flame retardant breaks apart
is reduced. Further, the lower viscosity flame retardants
within the scope of formula II of this invention will also
mix more rapidly with a given polymer.
Example 11
The thermal stability of compound 4 of Table I, t~is(2-
chloroethyl)phosphate, and tris(2,3-dibromopropyl)phosphate was
determined by the procedure set forth in Section 9-951, "Thermo-
gravimetric Analyzer , of Instruction Manual 990, Thermal
Analyzer and Modules", E, I. Du Pont De ~emours and Co, (Inc.),
~858~
Instrument Products Division, Wilmington, Delaware 19898. The
results of the thermogravimetric analysis (TGA) of the three
compounds at several different weight losses are tabulated in
Table IX as follows:
TABLE IX
~GA RESULTS
Temperature at which weight
Chanqe Occurs, C
Compound 10% wt~25% wt. 50/O wt.
Loss Loss Loss
Compound 4, Table I 285 307 323
Tris(2-chloroethyl)-
phosphate 182 197 209
Tris(2,3-dibromo-
propyl)phosphate 273 288 307
As exemplified by bis(2,3~dibromopropyl)-3-chloro-
2,2-bistchloromethyl)propyl phosphate, in Table IX, compounds
within the scope of this invention, e.g., bis(2,3-dibromopropyl)-
3-bromo-2,2-bis(bromomethyl)propyl phosphate, bis(2,3-dibromo-
propyl)-3-bromo-2,2-bis(methyl)propyl phosphate, bis(2,3-
dibromopropyl)-3-chloro-bis(bromomethyl)propyl phosphate,
bis(2,3-dibromopropyl)-3-chloro-2,2-bis(methyl)propyl phosphate,
and bis ~2,3-dichloropropyl)-3-chloro-2,2-bis(methyl)propyl
phosphate, possess superior thermal stability than that
possessed by prior art compounds.
Based on this disclosure many other modifications
and ramifications will naturally suggest themsel~es to those
skilled in the art. These are intended to be comprehended
as within the scope of this invention.
_ 28
