Note: Descriptions are shown in the official language in which they were submitted.
lOS;~924
Back~round of the Invention
Polymers of halogen-containing ethylenically unsat-
urated monomers, such as the vin~ or ~inylidene halides,
are often prepared as aqueous latices or emulsions in which
form they may be conveniently used as coatings, adhe~ives,
paint bases and in various other types of applications. In
many instances, particularly where they are being considered
for use in building interiors or in uses requiring their
prolonged exposure to high temperatures, it is highly desir-
able and advantageous that these latices ~hould display en-
hanced fire or flame retardant properties and color stability
so that they may be safely employed in place of more cottly
materials. MDr~over, it is highly desirable and advantageous
that these latices when applied to 1exible substrates, should
not substantially reduce the soft "hand" of said fl~xible
substrates.
Prior attempts to provide fire retardantt film-
forming vinyl or vinylidene halide polymer latices have in- ~ -
volved the preparation of various polymeric compo~itions
including copplymer latices of vinyl halides and alkyl
acrylates, copolymer latices of vinyl ha~ides and vinylidene
chloride and polyvinyl halide ~atices containing an extran-
eously added phosophate ester plasticizer. Other attempts
25have involved the use of interpolymers of bis(beta-chloro-
ethyl) vinyl phosphonate With lower alkyl acrylates or meth-
acrylates and acrylic or methacrylic nitriles~i These inter-
polymers cQuld additionally optionally include vinyl halides
or vinylidene halideo. Still other attempts have involved
interpolymo~szation of vinylidene halide monomers with
~OS'~9;~4
carboxylic acid monomers and N-alkylol amide monomers. These
latter interpolymers could optionally include other polymer-
izable comonomers such as esters of acrylic acid or methacrylic
acid, vinyl acetate, acrylonitrile, methacrylonitrile, acryl-
amide or methacrylamide, styrene or bis(beta-haloalkyl)
vinylphosphonates. However, despite the many and varied
attempts to obt~in a completely satisfactory polymeric latex,
none of the above-described approaches has proven to be com-
pletely satisfactory as the resultant products are found, in
many cases, to be lacking in either sufficient fire retard- -
ancy, softness of the polymer, color stability and mechanical
stability or ultravio~e-tstability or the products are su~ect
- to the gradual loss of their extraneously added phosphate
plasticizers.
Recent improv~ments in this technology have resulted
in fire retardant aqueous polymer emulsions comrising a
halogen-containing vinyl monomer such as vinylidene chloride,
a phosporus-containing vinyl monomee such as bis(beta-chloro-
ethyl)vinyl phosphonate, and another comonomer~such as an
alkyl acrylate. These emulsions, while vastly superior to
those previously known, can still stand further improvement.
It is particularlyidesirable to obtain highly stable fire-
retardant polymer compositions with even higher fire retard-
ant properties.
Accordingly, it is an object of this invention to
provide novelj fire retardant halogen-containing vinyl latices
which may be used in a variety of coating, binding, and lam-
in~ting applications and which are characterized by their
essentially complete freedom from the various disadvantageeus
properties herefofore associated with this type of product.
105'~9Z4
It is another ob~ect of this in~ention to provide
a novel class o~ pol~mers in the form of unusually stable
aqueous emulsions of latices which are particularly useful,
:~ as additives, for preparing fire retardant, polymer compositions
; which are in the form of aqueous solutions, suspensions, or,
most preferably, emulsions.
It is a further object of the present invention
to provide a method for preparing highly stable polymeric
. latices.
Thus, in accordance with the present teachings,
a process is provided for preparing a stable, fire-retardant
` polymer latex which comprises: ~
~ (i) admixing water, and (1) from 10 to 98% :
.l by weight of a halogen-containing ethylenically unsaturated
monomer, said halogen being selected from the group consisting
.- of fluarine, chlorine and bromine, (2) from 1 to 89% by
1 weight of a bis (hydrocarbyl) vinyl phosphonate of the formula:
`i X O
:~ CH = ~ OR'~ :
- OR '
in which x is selected from the group consisting of hydrogen, ~
fluorine, chlorine, bromine, cyano, phenyl, alkyl of from l
to 18 carbon atoms and the grouping
O
s q~OR'~
- OR
and each of R and R' is selected from the group consisting of
. alkyl of from 1 to 18 carbon atoms, alkenyl of from 2 to 18
carbon atoms, and may be combined to form a single radical,
cycloalkyl of from 3 to 8 carbon atoms, phenyl, benzyl,
phenethyl, tolyl and naphthyl, and (3) from 1 to 45% by weight
of at least one monomer selected from the group consisting
of alpha olefins, vinyl esters of carboxylic acids, Cl-C20 alkyl
)~ .
lOSZ924
esters of acrylic and methacrylic acid, ethylenically un~
saturated dicarboxylic acids, an~ydrides of ethylenically
unsaturated dicarboxylic acid, Cl-C20 mono- and di-alkyl
esters of ethylenically unsaturated carboxylic acid and
their N-methylol and diacetone derivatives; vinyl aryl
compounds; Cl-C20 alkyl vinyl ethers; C4-C20 dienes, and
glycidyl esters of acrylic and methacrylic acid;
~ ii) admixing therewith a sodium sulfosuccin-
amate emulsifier of the formula:
CH2-l-N = R
NaOSO2-CH -C-O-Na 2
O
in which Rl is hydrogen, a hydrocarbyl radical having from
1 to 18 carbon atoms or di-sodium 1,2-dicarboxyethyl, and ~2
is a hydrocarbyl radical having from 1 to 18 carbon atoms;
(iii) admixing therewith a free radical
generating catalyst, and effecting polymerization of the
monomer admixture to obtain a stable latex.
. 20 Vario.us other objects and advantages of this
; invention will be apparent from the disclosure thereof which
follows hereinafter.
Technical Disclosure of the Invention
`. In its broadest aspect, this invention resides
in the discovery that aqueous emulsions of fire retardant poly-
mers comprising (1) one or more halogen-containing vinyl
monomers with (2) one or more phosphorus containing vinyl
monomers as hereinafter defined, and (3) one or more additional
comonomers as hereinafter further defined, these polymers
being in the form of unusually stable dispersions of particles
in an aqueous emulsion or latex, are prepared by an emulsion
polymerization process using as an emulsifier a sodium sulfo-
G ~ -4a-
.
~05'Z924
succinamate of the general ~ormula;
O
CH2-C~N ~ R
NaOSO2-CH-C-O-Na 2
.' O
in which Rl is hydrogen, a hydrocarbyl radical having from 1
to 18 carbon atoms, or di-sodium 1,2-dicarboxy ethyl; and R2
is a hydrocarbyl radical having from 1 to 18 carbon atoms.
:'
j :.
~, ' .
:-
-4b-
,~ . .
105'~924
Preferred as R2 are hydrogen, alkyl radical~ having from 16
to 18 carbon atoms, or di-sodium, l,~-dicarboxy ethyl.
Preferred as R2 are alkyl radicals having from 16 to 18
carbon atoms. Especially preferred as emulsifiers are
S tetra-sodium N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccin-
amate and di-sodium N-octadecyl sulfosuccinamate: these emul-
sifiers are sold under the trademarks Aer0sol 2? and Aerosol
18, respectively, by American Cyanamid Company.
More particularly, it has now been discovered that
the use of a sodium sulfosuccinahate emul-sifier enables the
preparation of highly stable aqueous emulsions or latices of
polymers formed from one or more halogen-containing vinyl
monomers with one or more bis(hydrocarbyl) vinyl phosphonate
and one or more additional comonomers as hereinafter defined
in an emulsion polymerizaiton process. These stable poly-
meric emulsions when blended with an ordinarily fla~mable
polymer, impart to the resulting polymer blend a high degree
of fire retardance and excellent color stability without
adversely affecting any of the significant physical proper-
tieæ of the polymer. In addition, it has been found that the
polymer additives of the present invention impart a desirably
soft hand to substrates upon which they are coated or w~th-
in w~hch they are impregnated. Moreover, it is truly sur-
prising and advantageous to find that the polymer blendsresulting from the process of this invention, particularly
those blends which are in the form of an aqueous emulsion or
latex system, display an outstanding degree of compatibility
since, as is well known to those skilled in the art, physical
blends of two or more polymers are almost always character-
ized by their inherently poor compatibility. The process of
this invention provides highly stable aq~eous emulsion or
latex polymers comprising:
~05'~924
(1) at least one halogen-containing, alpha, beta-
ethylenically unsaturated monomer, i.e., vinyl monomers in-
cluding vinyl halides such as, for example, vinyl chloride,
vinyl fluoride and vinyl bromide, halogenated Cl-C12 alkyl
acrylates and methacrylates such as, for example, methyl
alpha-chloroacrylate and methyl a~pha-bromoacrylate; vinyl-
dene halides such as, for example, vin~ldene chloride,
vinylidene bromide, vinylidene chlorobromide and vinylidene
'~ fluoride; halo-bubstituted nitriles of ethylen~cally unsa~-
'~ 10 urated carboxylic acids such as, for example, alphachloro-
acrylonitrile; and the chlorinated styrenes such as, for
example, alpha-chlorostyrene, o-chlorostyrene, m~oh~
styrene, p-chlorostyrene and 2,4-dichlorostyrene.
(2) at least one bis(hydrocarbyl)vinylphosphonate ;~
having the structure:
' X o
C 2 C p
`: :
~'wherein-~X--is s'~ct~d fr~m':~h~-~g~ Wo~n~istl~n~iof-hyd~ogen,
':h i~ge~Y~yan~ $~r'su~h~a~ ~henyIt ~l Qi8 Y
O
OR'~ ;
~' ~ OR-' , wherein -
R and R' are hydrocarbyl and substituted hydrocarbyl groups
consisting essentially of hydrogen and carbon~and containing
up to about 18 carbon atoms inclusive with the proviso that
' R and R' may be the same, different or conjoint, i.e., R and ' ''
R' may combine to form one single radical; and
(3~ optionally at least one comonomer including alpha "
elefins such as ethylene, propylene and butylene; vinyl esters
of carboxylic acids, such as vinyl acetate, vinyl butyrate
~ - 6 -
)~\
105Z9Z4
and vinyl stearate; and Cl-C20 alkyl esters of acrylic
and methacrylic acid such as methyl methacrylate, methyl
acrylate, ethyl acrylate, n-butyl acrylate, sec.-butyl
acrylate, tert.-butyl acrylate, 2-ethylhexyl acrylate,
105Z9Z4
lauryl acrylate and the like; ethylenically unsaturated di-
carboxylic acids, their an~ydrides and their Cl-C20 mono-
and dialkyl esters such as aconitic acid, fumaric acid,
maleic acid, itaconic acid, citraconic acid, maleic anhydride,
dibutyl fumarate and monoethyl maleate; amides of ethylen-
ically unsaturated carboxylic acids such as acrylamide and
methacrylamide and their N-methylol and diacetone deriva-
tives such as N-methylol acrylamide, N-methylol methacryla-
- mide and diacetone acrylamide; vinyl aryl compounds such as
styrene and alpha-methyl styrene; Cl-C20 alkyl vinyl ethers
such as methyl vinyl ether, ethyl vinyl ether and stearyl
vinyl ether; dienes such as isoprene and butadiene; and
glycidyl esters of acrylic and methacrylic acid such as
l glycidyl acrylate and glycidyl methacrylate. The preferred
-, 15 comonomers are the Cl-C20 alkyl esters of acrylic and meth-
- acrylic acid, e~pecially the lower (C4-C8) alkyl acrylates.
It is considered preferable to include the N-methylol
and diacetone derivatives of amides of ethylenically un- --
saturated carboxylic acids such as~ for example, N-methylol
acrylamide or diacetone acrylamide which serve to provide the
resulting polymer w-ith cross*linking si~es.
The use, in this disclosure, of the expression
"hydrocarbyl'! and "substituted hydrocarbyl groups" in the ~- ~
definition of the suitable bis(hydrocar~yl)vinylphosphonates ~ -
given hereinab~ve refers to the radicals obtained upon the
removal of a hydrogen from a hydrosarbon or substituted hydro-
carbon group which may be either an aliphatic or aromatic
group. These hydrocarbyl gr~ups may be substituted with any
non-interferring groups, i.e., with any group which does not
interfere w~th the polymerization of the bis-(hydrocarbyl)
~05Z9Z4
vinylphosphonate. Such sub~tituent groups include, for
example, chloro, bromo, fluoro, nitro, hydroxy, sulfone,
ethoxy, methpxy, nitrile, ether, ester and keto groups
and the like.
Illustrative of the aliphatic and aromatic groups
. as are represented by R and R' in the structure of the
. bis-(hydrocarbyl)vinylphosphonate given hereinabove are
alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl,
hexyl, nonyl, and the like; alke~yl groups such as pentenyl
. 10 and hex~nyl groups and all of their respective isomers;
. cycloalkyl groups, such as cyclopropyl, ~yclobutyl, cyclo-
:~ pentyl, cyclohexyl and the likei cycloalkynyl groups such
as cyclohexenyl and the like; typical aryl gooups inc~udQ
phenyl, benzyl, phenethyl, tolyl, naphthyl and the like.
Representative of the above-defined bis(hydrocarbyl)
~ .vinylphosphonates are: ;
: Bis(beta-chloroethyl) vinylphosphonate;
Bis(beta-chloropropyl):vinylphosphonate;
~ Bis(beta-chloroethyl) l-methylvinylp~osphonate;
.~ 20 Bis(be~a-chloroethyl) -l-cyanovinylphosphonate;
;Bis(beta-chloroethyl~ c~ lp~o~pbs~atc~
Bis(beta-chloroethyl) -l-phenylvinylphosphonate;
Dimethyl vinylphosphonate;
. 25 Diethyl vinylphosphonate;
Bis(omega-chlorobutyl~ v~nylphosphonate;
Di-n-butyl vinylphosphonate;
~i-isobutyl v~.nylphosph~nate;
Bist2-chloroisopropyi~ met~ylv~n~lpho~p~onate;
Diphenyl v~.nylphosphonate; and
Bis.t2,3-dibromopropyl~ ~n~lph~sp~nate
- 8 -
lOSZ924
From the above group of bis(hydrocarbyl)vinyl-
phosphonate monomers, it i5 preferred to employ bis(beta-
chloroethyl) vinylphosphonate in preparing the novel aqueous
emulsion polymers of this invention since the latter monomer
is a commercially available material and lower in c~st than
any of the other bis(hydrocarbyl~vinylphosphonates.
Although either a vinyl halide or a vinylidene
halide monomer can be suitably employed as the halogen-
containing ethylenically unsaturated monomer in the aqueous
emulsion polymers of the present invention, it is considered
preferable to employ vinylidene halide monomers since the
vinylidene halide monomers when incorporated into polymers
of the present invention impart a soft "hand" to substrates
upon which they are coated or w~thin which they are impreg- ~ -
nated. The preferred third comonomer for use in the poly-
; mers of the present invention is an alkyl acrylate, prefer-
ably the C4-C8 alkyl acrylates such as n-butyl acrylate and
2-ethylhexyl acrylate. It has been found that inclusion in
; the polymer of an alkyl acrylate aids in imparting good
aQ color stability and softness to the resulting polymer. It -
is to be noted, at this point, that the use of the term
"polymer~ in this disclosure is meant to apply to polymers
derived from two or more distinct monomeric spe¢ies.
In addition to the above described bis(h~drocarbyl)
vinylphosphonates, it is also possible to prepare aqueous
emulsion polymers useful as flame retardant additives by ~ -
employing~ mono(alkyl~acid vinylphosphonates such as,
fqr example, mono(ethyl~ hydrogen vinylphosphonates mono
(butyl~ hydrogen vinyiphosphonate, mono(octyl~hydrogen vinyl-
phosphonate, mono(beta-chloroethyl~ hydrogen vinylphosphonate,
mono(omega-chlorooctyl~hydrogen vinylphosphonate; ~2~ mono
,,
. .
105Z924
(cycloalk~l) and mono(aryllhydrogen vinylphosphonates such as,
for example, mono~cyclohexyl)hydrogen vinylphosphonate,
mono(phenyl)hydrogen vinylphosphonste, mono(benzyl)hydrogen
vinylphosphonate; (3) bis(cycloalkyl) and bis(aryl)vinyl-
phosphonates, such as, for example, bis(cyclohexyl)vinyl-
phosphonate and bis(benzyl)vinylphosphonates; and, (4) bis
(alkyl), bis(cycloalkyl), and bis(aryl) allylphosphonates,
such as, for example bis(beta-chIoroethyl)allylphosphonate,
bis(cyclohexyl) allylphosphonate and bis(benzyl)'allylphos-
; 10 phonate as well as mixtures of any two or more of the above
described phosphonate monomers.
The polymers of the present invention are prepared
by means of free radiaal initiated emulsion pplymerization '
techniques well known to those skilled in the art. In these
procedures, the various monomers and catalysts are emulsified,
in water, by means of the emulsifiers of the present inven-
tion whereupon the polymerization r~aC~$on is then initiated.
Suitable water soluble, free radical initiating catalysts
; for use in preparing the polymer latices of this invention
include sodium, potassium and ammonium persulfate an~ '
hydrogen peroxide. Alternatively, one may use a redox
system such ~-fior example, as a mixture of a persulfate with ~-
an al~ali metal b~sulfite, thiosulfate or hydrosulfite.
These catalysts should be present in a concentration of from
about 0.05 to 5.0%, by weight, of the total monomer charge. -~
The sodium sulfosuccinamate emulsifiers employed in
the present invention have been found to impart surprisingly
enhanced stability to the emulsi~Dnof latex polymer additives
of the present invention. In the absence of at lea~t about
0.03% by weight of the emulsifiers based on the total momo-
,
- 10 -
105Z924
mer charge, the gum and floc levels of the resulting emul-
sions or latices have been found to be exceedingly high;
whereas, when the sulfosuccinam~te emulsifiers are employed,
preferably in amounts of from about 0.03% to about ~% by
S weight, based on total monomer charge, gum and floc in the
resulting emulsion or latex is substantially elîminated and
the stability of the emulsion or latex is retained for ex- -
tended periods of time. The emulsifiers can be employed in
amounts greater than about 3%, if desieed without detri-
mental effect.
~ In addition, a protective colloid such as polyvinyl
alcohol, polyvinyl pyrrolidone, methyl cellulose or gelatin
can also, if desired, be present in the recipe in an effec- ~
tive concentration of from about 0.03 to 6.0%, by weight, of ~;
the total monomer charge. Alternatively, the protective
; colloid may be introduced into the polymer latex subsequent
` to its preparation. When post-added in this manner, the ~;
protective colloid should be preæent in a concentration of
from about 0.03 to 6.0%, by weight, of the total resin solids.
In any event, the presence o the protective colloid serves
to fnuther enhance the mechanical stability of the emulsion.
The actual polymerization reaction will ordinarily
be conducted at a temperature of from about 0 to 100C. for
a period of from about l to 24 hours, depending upon such
factors as the particular monomer, catalysts, surfactants
and polymeriza*ion apparatu~that is being utilized. The
l~tices resulting from this polymerization process will
ordina~ily have a resin solids content of from about 5 to
70~, by weight, wherein the particles have a diameter which
ranges in size from about 0.03 to 3.0 microns.
-- 11 --
1052924
With respect to pooportions, these aqueous emulsion.
or latex copolymer particles may contain from about 1 to 89%
by weight, of one or more of the above-described bis~hydro-
carbyl) vinylphosphonates, from about 10 to 98% by weight
of one or more of the above-described halogen-containing
ethylenically unsaturated monomer~ and from about 1 to 45%
by weight of one or more of the above-described third co-
monomers. Optimum results, as flame retardant additives
exhibiting good color stability for ordinarily fla~mable
polymer substrates adapted to impart good "hand" to said
substrates are obtained by use of polymers in accordance
with the present invention containing from about 10 to 75% by
weight of one or more of the bis(hydrocarbyl) vinylphospho~.
nates, from about 20 to 85% by weight of one or more of
the above-described halogen-containing ethylenicall~ unsat-
urat~monome~s and from about 5 to 35% by weight of one or
more of the.above-described third comonomers. Most pre-
.ferred.is a polymer containing about 45-554 by weight-of
bis(beta-chloroethyl) vinylphosphonate, 25-35% by eight of
vinylidene chloride, 14-20% by weight of n-butyl acrylate
and 1-5% by weight of N-methylol acrylamide. n-butyl acrylate
can be replaced, without affecting the properties of the
~` ~ latex polymer, by 2-ethyl.hexyl acrylate. When 2-ehhyl
hexyl.adrylate is used, the most preferred composition con-
tains.65=~5~ by-weight of vinylidene chloride, 12-22% by
weight of bis(beta-chloroethyl~ vlnylphosphonate, 5-13~. by
weight.of 2-ethylhexyl acrylate and.1-5% by weight of n-
methylol acrylamidç. These two preferred compositions pro-
vide a proper balance of all the desired properties and are
30 e~sent.ially free ~om the varioss.disadvantageous properties
associated heretofore with this type of polymer emulsion or
- 12 -
lOSZ9Z4
latex.
With respect to the above-described proportions
for the composition of the aqueous emulsion or latex co-
polymers of this invention, it has been found that it be-
comes increasingly more difficult to attain good polymeri-
zation conversion rates as attempts are made to increase
the amount of the bis(hydrocarbyl~ vinylphosphonate in the
resulting cop~lymer substantially above a concentration of
about 60% by weight. On the other hand, the use of these
copolymer emulsions as flame retardant additives for ord-
;~ inarily flammable polymer-substrates becomes progressively
more inefficient when they contain substantially less than
about 5% by weight of one or more bis(hydrocarbyl~ vinyl~
phosphonates, since the resulting blend will then require
the presence of a rather high concentration of the polymer
in order to attain flame retardance. The use of such high
coneentrations of theæe polymer addi~ives may, in turn,
result in so~e deterioration m~ the ihherent physical pro-
... . . . .
perties of the thus modified polymer substrate.
1 ~Speclfic aqueous emulsion polymer compos~tions
which are particularly preferred are:
a terpolymer of 81 parts by weight of vinyl-
idene chloride, 5 parts by weight of n-butyl acrylate and
' 14 parts bylweight of bis(beta-chloroethyll vinyl phospho~-
,- 25 nate;
i (21 a tèrpolymer containing 15 parts by weight of
; di-n-butyl vinyl phosphonate, 20~parts by weight of di-n-
octyl fumarate and 65 parts by weight of vinylidene chloride~
~ ~31 a terpol~mer containing 15 parts by w~ight
bis(beta~chloroethyll vinyl phosphDnate, 5 parts by weight
~ .
- 13 -
...
1052924
propylene and 80 parts by weight vinylidene chloride;
(4) a terpolymer containing 25 parts by weight
vinylid~ne bromide, 65 parts by weight bis~beta-chloroethyl)
vinylphosphonate and 10 parts vinyl.acetate; and
(5) a polymer containing 50 parts by weight vinyl
chloride, 35 parts by weight bis(2-chloroisopropyl) l-methyl
vinyl phosphonate, 15 parts by weight stearyl vinyl ether
and 5 parts by weight N-methylol acrylamide.
It is important, with respect to this disclosure, to
10 distinguish between the processes of suspension and emulsion
polymerization. Thus, suspension polymerization refers to a
method.of polymerizatlon whereby one or more monomers is f
dispersed in a suspension medium which is a non-solvent for
both the monomer and the resulting polymer. Generally,
water is utilized for this purpose and a monomer soluble
polymerization inltiator is thereupon introduced. Polymeri- ~ .:
zation takes place within the monomer phase containing the - .
polymerization initiator. ~he use.of..the suspending.medium
; assists in the di~sipation of the heat of reaction and the
polymerization:reaction is therefo.re easier to control.
Suspension polymerization is generally accomplished-by dis-
persing..the monomer in the suspending medium either by
conætant agitation or by the:.use.of a suspending agent or
. both.. Various suspending a~entSI.are.known in the.art. These
kno~.suspending agents.include.gelatin, hydroxy methyl
cellulose, hydroxy ethyl cellulose,..hydroxy prop~ cellulose,
carboxy.methyl cellulose, talc, clay,.polyvinyl alco~ol, :
and the like.
.. By contrast, emul8ion poly~erization, the process
.~
used in the present inven*ion, invQlves a proce~s ~hereby
one or more monomers~are emul~ied.in t~e form of droplets
, ~
~, , . . ~
105'~9~4
vithin a continuous phase which should be inert with respect
to both the emulsified monomers and the resulting polymer.
3,
Water is generally selected as the continuous phase.
Emulsification of the monomers is effected by the use of one
S or more of the above-described emulsification agents which :~
~ tend to reduce the interfacial tension between the dispersed
- and continuous phases.
j A water soluble initiator is.employed and it is
.` believed that the polymer chains originate in the continuous,
,: 10 aqueous phase and then continue their growth in the dispersed . -
. mono.mer-polymer phase yielding the polymer product in a finely
divided state which remains emuLsified within the continuous, ~.
aqueous medium. Thus, an important distinction between
emuls~on and suspension polymer.ization is that in the former, -.
lS the monomer is either dispersed.into.droplets which are
stabilized by~an adsorbed.layer of-..soap molecules or-is
solubilized in the soap micel.le.which is present in aq~eous
soap.solutions. As a~.result, atable.polymer emulsions are
readily.obtained whereas, in.. a 4uspension polymerization, . ~-
the resulting polymer..par.ticles...are.of. a relatively làrger
mass wAich tend to more readlly...separate.out from the
suspension. ..
In..all cases,.the aqueous~e~ulsion or latex co-
poly~ers of.this invention...haYe been.found to.provlde b~ends
with ordinarily flammable p~lymeric ~aterials ~hich are
characterized by.their outstanding.-f~re retardance. As used
in t~i~ disc~osure, the term...'~ .r.e.retardant" or "~lame
retardant" i~ intended.to re~er to t~at particular pro~erty
of a.mater~al.~hich provides..it.wtt~ a degree of resi~tance
to ~g~t an ..and~~un~n~ .$-~ë~ori ~14~e..ret~dant
.
. - . , .
105'~9~4
composition i8 one which has a low level of flammability and
flame speead. This property may be conveniently ev~luated
by means of any of the standard flame retardancy tests such
as, for example, the ASTM test D-635. . .
As has been indicat~d, hereinabove, the aqueous
emulsion or latex copolymers of this invention are particu-
. larly suitable for blending with ordinarily flammable poly- ..
, mers which are in the form of aqueous sy~tems such as solu-
: tions, suspensions, or, most preferably, emulsions. The
: 10 resulting aqueous blends may thRn be used in any of the
various coating, adhesive, ~aminating,.and impregnating
- applications known to those skilled in the art. Thus~ these ~.
: aqueous blends may be coated upon and/or absorbed by all ~-
;~ types of materials to which it is desired to impart fire
retardant properties. They may, there~ore, be used as coat-
ings,-impregnants,ifillers, la~inants, and adhesives for
such substrates as wood~, paper/..~etals;.textiles ba~ed on
eighéelfibers or.blends.t~ereof.;~.sy~t~eticipolymer ~llms
such as those based..opon p.olyoleips,.~egenerated cellulose,
~.e.,.cellop~ane polyvinyl.c~lor~d~,..polyeaters, and the
like7 leat~er.;:natural.and ~ynthetic rubher; fiber~boaxd;
and`s~n~hetic.pla$tics.~prepared by..:mean6 of e~ther addit~on
or conden-ation polymeriza~on te~hnigues. In addition, the
polymeræ.of.this invention. may- be e~p.lo~ed as fixe retardant
additives in the spinning:baths or.dop~s rom ~bich rayon
and acrylic fibers are spun.
In effect, one may utilize an~ ordinarily flammable :.
polyme~ic mat~ri~l in prepar~ng f~re.retardant polyblends
with the novel.aqaeQus emuls~bn p~lymer of this invention.
These ordinarily flammable polymer~c.materials may be thermo-
- 16 -
, :
.~ ~
~05'~9Z4
plastic polymers, i.e., polymers which can be softened
;- by heat and which then regain their ofiginal properties on
.. - cooling. Also applicable are polymer systems, particularly
those in aqueous emulsion form, comprising copolymers con-
5 taining one or more crosslinkable comonomers, i.e., monomers
contain~ng two or more functional groups, such, for example,
as N-methylol acrylamide, N-methylol methacrylamide, glycidyl
acrylate and glycidyl methacrylate. Thus, the copolymer.s ~;
containing one or more of these crosslinkable comonomers
can be cured or crosslinked~by theluse ~ heat a~d~or
catalysts and are thereby converted into a form ~n which
thèy will no longer be thenmoplastic but, will, rather, be
thermosetting, i.e., they will not soften upon being heated.
Ideally, the novel aqueous emulsion copolymers~of this in-
~ 15 vention are blended with such crosslinkable copolymer sys-
tems prior to the time they undergo.this curing or cross-
lihking operation.
The actual blending of.the aqueous emulsion copoly-
mers of this invention with other polymeric materials may be
accomplished.by.means.of any convenient procedure whiah
will resul:t in an intimate admixture o~ the instant copolymer
within.the poiymeric mass... Thus,~for example, the aqueous :~
emulsion or latex of the.present.invention may slmpl~ be
blended.or otherwise admixed with a.polymer ~hich should,
as preferably, be.in the form of an aqueous:solutlon, latex or
s.uspension. The resulting.a~ueou~ blend can be useful as .
such or can.be co-coagulated t~ ~or~a solid polymeric blend.
Or, if desired, the aqaeous..polymeric emulsion of this in-
vention can.-be coagulated by freezing or by addition o~ NaCl
solution,. methanol.~*.t~e L-~ ee~e~ ~he ~ol~e~ ~n
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105'~924
solid particulate form. The polymer additive and a polymer
to be modified may be admixed while each is in the form of
a solid.
The blending operation may also be carried out by
means of a procedure in which the polymer which i9 to be
modified is itself polymerized while in the presence of
one of the previously polymerized aqueous emulsion polymers
of this invention. Alternatively, the-bis(hydrocarbyl)
vinyl-phosphonate-containing aqueous emulsion polymers may
be polymerized in a system which contains the previously
polymerized polymer to be modified in an appropriate physical
form, e.g. as an aqueous solution, suspension or emulsion.
~!, With respect to proportions, the amount of bis(hydro-
carbyl) vinylphosphonate-containing aqueous emulsion or latex
polymer which may be admixed with an ordinarily flammable
polymeric material will depend, primariIy, upon such factors -
as the particular phosphonate polymer and the polymers
which are to be blended with one another, the degree of fire
retardancy desired in the resulting blend, the degree of - -
clarity, hardness and other specific physical properties
which are sought as well as other technical and economic
considerations known and understood by those skilled in the
art. However, in order to attain a composition which will ~ ~;
be self-extinguishing, it is generally desirable to intro- ;
duce an effective concentration of bis(alkyl) vinylphos-
phonate aqueous emulsion polymer solids which will be suffi-
cient to provide the re~ulting blend with at least about 0.5%,
by weight, of phosphorus and with at least about 10%, by
weight, of halogen, i.e., chlorine and/or bromine, derived
from the halogen containing ethylenically unsaturatea monomer
and also, if possible, from the bis(hydrocarbyl~ vinylphos-
phonate. - 18 -
lOSA~9Z4
: The fire retardant polymer compositions of this
invention can be prepared 80 as to contain various optional
additives which may include plasticizers such as the alkyl
esters of phthalic, adipic and sebacic acids such, for
5 example, as dioctyl phthalate and ditridecyl phthala~ -
and aryl phosphate esters such, for example, as triphenyl and
tricresyl phosphate, etc.; lubricants and mold release
agents such as stearic acid or its metal salts, petroleum
. based waxes, mineral oils and their halogenated products,
10 polyethylene waxes and their halogenated products, etc.;
.: and heat and light stabilizers such as barium, cad;iu~
calcium, zinc soaps or phenates, basic lead compounds,
organo-tin compounds, such as di-alkyl tin mercaptides and ~
di-alkyl tin maleates, th la~n~canhydride and n-butyl : -
stannoic acid, epoxidized oils, alkyl diphenyl phosphites,
triaryl.phosph~tes, phenyl salicylates, o-hydroxy benzo- ~:
phenones and benzotriazoles, etc. For a more complete list-
ing of plasticizers, lubrican.ts,.stabilizers and other
functional additives, one may consult "Poly~inyl Chloride"
20 by ~A. Sarvetnick published.by Van Nostrand Reinhold Co.,
: New Yor~, New York, in 1969.
The-Oompositions of this inventian may also contain :
fillers, pigments, dyes, opacifying~agents, decorative addi-
: tives such as reflective metal foils or flakes, and other
imbedded solid objects such.as fiber glass, textile ~i~ers,
asbestos and the like, provided that they~do notld~tra¢t';fr~m
the flame retardancy of.hhese products. In addition, the
compositions may contain other ~la~e.retardants such as
antimony compounds, zinc borate, aluminum hydrate, halo-
genated alkyl phosphates or phosphonates, alkyl acid phos~
phates, or small concentrations of phosphoric acid.
-- 19 --
105'~9Z~
The fire retardant compositions of thi~ invention,
whether comprising blend~ of polymeric materials with one
or more of the fire retardant additives of this invention
or whether comprising the fire retardant polymers of the
present invention, per se, may be utilized in any of the
coating, adhesive, impregnating, lamina~ing, binding and
painting applications known to those skilled in the art
wherein it is desired to provide fire retardancy to the
resulting end product. For example, these compositions may
. 10 be used in such applications as rug and carpet backing ad-
hesives, as adhesives for fi~er glass, as a backing coating `~
for fabrics, as heat sealable binders for non-woven ~abrics,
as flooring, coatings, as paper coatings, as paint bases
and as adhesives for preparing laminated structures.
In addition to being used as fire retardant addi-
tives for the preparation ~f fire retardant polymer blends
with fla~mable polymer substrates,. the aqueous emulsion ~ :
polymera of this invention.may be usedt per se, in any of the
~a~Gusc~t~n~,painting adhesive, laminating, impregnating
and binding applications knawn to those.skilled in the art.
Thus, they may be coated upon and~or adsorbed by all types
of substrates to which it is desired to impart fire retar-
dant properties. Tkey may, therefore, be used as boatings, :~
impregnants, fillers, laminants. and adhesives for such sub-
strates as wood; paperJ metals, non-woven fabrics and tex-
tiles based on either natural, s~nthetic, mineral or glass
fibers or blends thereof; synthetic polymer films such as
those based upon ~ly~le~ns,regenerated cellulose, i.e.
cellophane, polyvinyl chloride, polyesters and the liket
leather, natural and synthetic rubber; fiberboard, and, syn-
thetic plastics prepared by means of either addition or
~ - 20 -
':
.' ' :
105;~924
condensation polymerization techniques.
The following examples will further illustrate the
various embodiments of this invent~on. In these examples, all
, parts and percentages given are by weight unless otherwise ~te-
noted.
: ~ :
' ' ,
~ ~:
'
:' ," ~.
. .
,
; ' .
, .
- 20a -
.: . .
.:
~05'~9Z4
EXAMPLE I
.
This example illustrates the effectiveness of
sodium sulfosuccinamates as emulsifiers for preparing stable
polymeric latices. This example also illustrates that other
emulsifiers, heretofore considered equivalent to sodium
sulfosuccinamates as emulsifiers for polymeric latices pre-
pared from one or more of the monomers employed in the pre-
sent invention (See, for example, U.S. 3,489,706 and 3,682,
~; 871), are in fact, not equivalent and essentially unsuitable
for use in the preparation of the stable latices of the
- present invention.
Into a 32 ounce polymerization vessel, there are
charged 150 grams of bis(beta-chloroethyl~ vinylphosphonate,
- hereinafter referred to as "bis-beta", 15 grams N-methylol
lS ac~ylamide, 60 grams vinylidene chloride, 280 grams deion-
ized water and 60 grams of a 10% aqueous solution of tetra-
sodium N-(1,2-dicarboxyethyl~-N-octadecyl sulfoauccinamate.
The pH of the resulting mixture is adjusted to a value of 7
by addition of 3.3 mls of 58% aqueous solution of ammonium
hydroxide, whereupon 4~ grams of a 10% aqueous ammonium
persulfate solution is added to the mixture. The a~r space
above the liquid level in the reactor is purged wit~h nitrogen
and the veesel is sealed. The vessel is shaken to form a
", stable emulsion. Polymerization is effected at a temperature
of 50C. over a period of 12 hours with a:polymerization
vessel being continuously su~jected to a tumbling agltation.
extremely stable latex of good color stability is obt~ined
exhibiting a gum and fl~c-level of less than 1%. When the
- latex is poured onto a Petri dish and dried, a film exhibit- ing a soft hand is reco~ered. When ignited with a Bunsen
- 21 -
lOS'~924
burner for two seconds and the burner then removed, the
film does not support combustion and therefore exhibits
good RR properties.
A portion of the emulsion prepared above is blended
with an aqueous emulsion containing 46~ of polybutyl
acrylate polymer particles whose films are ordinarily
~ flammable. The concentration of the bis-beta p~lymer solids
i in the blend is 20% based on the polybutyl acrylate solids. ^-
A film having a dry thickness of 5 mils is cast from the
polymer blQnd and is found to exhibit a good fire retarda~cet
COMPARATIVE EXAMPLE 1
Example 1 is repeated except that 60 grams of a 10
aqueous sodium lauryl sulfate solution is employed in the
emulsifier in lieu of the sodium sulfosuccinamate employed.
Polymerization is effected under identical conditions. The
ulting emulsion is characterized by all floc.
EXAMPLE 2
Example 1 is repeated except that di~di~ -~-octa- -
decyl sulfosuccinamate is em~lpyed in lieu of tetrasodium
N-(1,2-dicarboxyethyl~-N-octadecyl sulfosuccinamate. A
stable latex is similarly obtained.
.
- 22 -
