Note: Descriptions are shown in the official language in which they were submitted.
;5~;;
1 BACK~ROUND OF IHE INVENTION
2 This invention relates to a method for producing
3 aqueous em~lsions and latices of sulEonated low unsatura~ion
4 elastomers More par~icularlyJ the in~ention relates to an
improvement in carrying out the passivation or quenching o
6 the elastomer cement sulfonation reaction in order to pro-
7 duce a more readily emulsifiable product and pro~ide a more
8 eficient overall latex process.
9 Sulfonated ionomers of butyl rubber and ethylene-
propylene-diene terpolymers are described, for example, in
11 Canter, U. S. Patent 3,642,728, February 15s 1972.
12 Latices prepared from sulfonnted butyl rubber are
13 disclosed in l~ubbard et al U.S. Patent 3,770,682, November
14 6, 1973, wherein the acid form of the sulfonated butyl
rubber is emulsified using a nonionic surfactant.
16 O'Farrell, U.S. Patent 3,912,683, October 14, 1975, deals
17 with the emulsification of neu~ralized sulfonated butyl
18 rubber with an anionic surfactant. O'Farrell et al, U.S.
19 Patent 3,836,511, September 17, 1974, deals with the acyl
sulfate sulfonation of these elastomers.
21 In the aforesaid techniques for preparing sulfon-
22 ated elastomeric la~ices, substan~ial quan~ities of alco-
23 hol, such as n-propanol, have been required to quench or
24 passivate the sulfonation reaction. This passivation step
is essential in order ~o provide an emulsifiable produc~
26 which can be fur~her processed to give an acceptable la~ex.
27 The amoun~ of such alcohols used has been on the order of
2~ 20~40~/o by weight based on the weight of the sulfonated
29 elastomer cement. ~fter removing solvent, alcohol and
excess water from the initial latex to forrn the final
31 latex, the pl~esence of these quantities of alcohol requires
32 extensive distillation and purifica~ion procedures in
- 2 ~
655
1 order to separate the solvent, alcohol and water. ~len
2 alcohols, such as l-octanol, having boiling points
: 3 sufficiently high, such that they are not removed during
solvent stripping and concentration of the latex, have
been used, these alcohols remain as componen~s of the
6 finished latex and cause excessive coagulation and other
7 instability pro~lems in the finished product.
. 8 Another disadvantage with respect to the usc of
~ 9 an alcohol quenching agent has been the requirement that
::~ 10 fairly substantial amo~mts of emulsifier, such as 10 to 15
11 parts per hundred (phr~g be used per hundred par~s of sul- --
1~ ona~ed elastomer presen~ in ~he cement It is known that
13 alcohols can have an adverse effect on ~he surfac~ant pro-
1~ perties of anionic emulsifiersO
~5 SUMMARY OF THE INVENTION
16 In the present invention, the numerous disadvan-
17 tages resulting from the use of an alcohol passivating sys-
18 tem for the sulfonation reac~ion are o~ercome by employing
19~ an organic epoxide containing at least one reactive oxirane
functional group. The epoxide may be used in stoichiome-
21 trio amounts to passivate or quench ~he sulfonation reac-
22 tion.
23 In accordance wlth the present in~ention, there
2~ has been discovered a process for preparlng latlces of sul-
: 25 fonated low unsaturatlon elastomers, such as sul~onated
26 butyl rubber and sulfonated EPDM elastomers, which comprises
27 the steps of:
2~ ~a) providing a cement of the elastomer in a
29 vol~tile hydrocarbon solvent;
(b~ sulfonating the elastomer cement with an acyl
31 sulate sulfonating agent;
32 (c~ passivatlng the sulfonated cement with a
c;S5
.........
1 stoichiom~tric amount o~ an organic epoxide havlng 2~ least
2 one reactlve oxirane group, that is one -C~ `C- group;
(d~ providing an emulsion of the prod~ct in water
4 in neu~ralized fonm using an anionic surfactan~ emulsifying
agent, said product belng neu~ralized before or after emul-
6 sification uslng a weak base, and
7 (e) therea~ter strlpping off e~cess water and
8 solvent~ whereby a stable latex emulsion is obtained.
9 A further embodiment of the present invention re-
sides ln ~ st~ble late~ emulsion composition prepared ac-
11 cording to ~he above-descrlbed process. s
12 DETAILED DESCRIPTION OF l~lE INVENTION 3'1
13 The term "butyl rubber" as used in the specifica-
14 tion and claims means copolymers of isoolefins and conju-
gated dienes which comprises about 0~5 to a~out 15 mole ~/O
16 con~uga~ed diene and about 85-99.5% isoolefin~ Illustrative
17 examples of isoolefins which may be used in the preparation
18 of butyl rubber are isobutylene, 2~methyl-l~propeneg 3-
19 methyl~l-buteneg 4 methyl~l~pentene and bet~pirlene. Ex-
amples of conjugated dienes are isoprene, butadiene, 2,3-
21 dime~hyl bu~adiene, chloroprene, piperylene, 2,5-dimethyl-
22 hexa-2,4-diene, cyclopentadiene, cyclohexadiene and methyl-
23 cyclopentadiene. The preparation of bu~yl r~tbber is des-
24 cribed in U.S. Patent 2,356g128 as well as in an article
by R. M. Thomas et al in "Industrial and Engineering
26 Chemistry'l, Vol. 329 p 1283, Octobers 1940.
27 The ~erm "EPDMIi is used in ~he sense of its de-
28 finition as ound in ASTM-D-141B-64 and is intended to mean
29 ~ ~erpolymer contairling ethylene and propylene in the
backbone and a diene in the side chain. Illustrati~e methods
31 or producing these terpolymers are ound in U.S. Paten~
32 3,280,082, British Patent 1,030,289 and French Patent
~ 6 ~ ~
l 1,386,600. The preferred polymers contain about 45 to
2 about 80 wt. percen~ ethylene and abou~ 2 to a~out 10 wt.
3 percent o a cliene monomer, the balance of ~he polymer
4 being propylene. The diene monomer is preferably a
nonconjugated diene.
.. .. .
6 Illustrative o~ these nonconjugat~d d~ene monomers
which may be used ~n the terpolymer l(EPDM3 are hexadiene,
8 dicyclopentadieneg ethylidene norbornene, methylene norbor-
g nene, propylidene norbornene, and methyl tetrahydroindene.
A typical EPD~ is a polymer having a Mooney viscosity at
11 212Fo Of about 9Q prepared rom a monomer blend having an
12 ethylene content of abou~ 56 wt~ percent and a nonconjuga-
13 ted diene con~ènt of abou~ 206 w~O percen~.
14 The term "cemen~" as used in ~le specification
and claim~ means the viscous solution of butyl rubber or
16 EPDM polymer in a suitable ~olatile organic solven~; pre-
17 ferably ~he solvenk is an aroma~ic hydrocarbon solvent.
18 The sulfonated cement normally has a Brookfield vlscosity
19 of about 3,000 to 109 ono cps . (12 rpm; 2~C )O This cement
viscosity prior ~o sulfona~ion is preferably 39000 cps. to
21 6,000 CPSD~ such as 4,000 cps
22 The cement is flrst prepared by dissolving ~he
23 bu~yl rubber or EPDM in a sui~able aliphatic or aromatic
24 hydrocarbon or chlorina~ed hydrocar~on solvent such as
hexane, heptane, cyclohexane, dichloroethane, methylene
26 chloride, ~arbon te~rachlor~de~ ~oluene, benzene, xylene
27 and the like. Toluene is particularly sui table. Generally
28 speaking the solven~ should have a boiling point not greater
29 ~han about 125C~ and preferably has a boillng point less
than the boiling point of water or is capable of form-lng
31 an azeotrope, the azeo'crope having a boiling point less
32 ~han tha~ of wa~er, to facilitate solvent s~ripping ~uring
65i~
preparation o:f 'che latex in flnished form. The initial
2 concen~ration o ~he bu~tl rubber or EPDM polymer in solu-
3 tion is generally in the range of abou~ 5 ~o 50/O by weight,
4 pre-Eer~bly about 7 to 18% by weight.
In the practice o~ ~he present inven~ionl sulfon-
6 a~ion o~ the cement solution is carried cu~ using a~ acyl
7 sulate sulfonating agent. Su~table sulfonating agents
8 lnclude ace~yl sulfa~e~ propionyl sulfa~e or bu~yryl sul
g fa~e, wi~h acetyl sulfate being particularly preferred.
10 The acyl sulfate sulfona~ing agents or use in accordance
.11 with the presen~ inven~ion are prepared by reacting the
12 anhydride of a mono-basic acid with sulfuric acid or re-
13 acting the mono-basic organic acid wL~h S03~ Sulfonation
14 of unsaturated elastomers generally is described by O'Far-
rell et al in V.S. Patent 3,836,511.
16 The acyl sulfate may be prepared for use in solu-
17 tion but is preferably prepared neat, ~hat is~ in the ab-
18 sence of solventg by the additlon o concentrated sulfuric
19 acid to ~he corresponding anhydrideO Acyl sulfates may be
formed at about -100C. ~o ~50Cog more preferably -40 to
2-1 ~30C., such as abou~ 20C. Preferably the acyl sulfate
22 is prepared immediately prior to use. In si~u prepara~ion
23 is adequate, such as by adding anhydride to ~he polymer
24 solution and thereater adding sulfuric acid. When the
acy~ sulfate is prepared in the solvent prior to use, its
26 solvent concentration should be about 0.5 to 25 wt. %, more
27 preferably 1 to 20~/oJ most preferably 10 to 20%~ such as
28 18% by weight.
29 ~ul~onation of the butyl rubber or EPDM cement
may be carried out at any suitable temperature, for example~
31 -lQ0 to as high as 100C. Pressure ls not a crltical con-
32 dition and may be adjus~ed to any satisEactory level~ For
6~i5
,~
l instance, the sulfonation may be carried out rom a reduced
2 pressure of, say, about 005 atmospheres up ~o a super at-
3 mospherie pressure in the area of 10 a~mospheres and above.
4 The most suitable conditions rom an economic standpolnt
S are tempera~ures of 15 ~o 40C. and a pressure approximat-
6 ing atmospheric pressure. The sul~onation time will vary
7 with the particular conditions selected9 the polymer being
8 sulfonated and the degree o sulfona~ion desiredO Gener-
- 9 ally, the sulfona~ion reaction is comple~e wlthin a few
lo seconds to several hours a~er ~he reae~an~s are contacted
Il with each o~hern When sulfonating a~ approximàtely room
12 temperature and a~mospheric pressure, the contact tlme
l3 should be about 5 seconds ~o about 25 to 30 minutes.
14 The level of sulfona~ion in the po~ymers of this
lS ~nvention may vary from about 0008 mole % to about 15 mole
16 %0 Preferably the degree o sulfona~ion is about 0008 to
17 about 10 mole ~0, more preferably about Ool to abou~ 8 mole
18 %, most preerably about 0.2 to ~out 8 mole %.
19 Af~er carrying ou~ ~he sulfonatlon reac~ionJ the
sulfona~ed cemen~ is then passi~a~ed or quenched with an
21 organic epoxide containing a~ leas~ one reactive oxirane
22 group. Organic epoxide compounds generally are suitable
23 for use in the practice of the present in~ention provided
24 they contain a~ leas~ one such oxirane group capable of
reacting with ~he S03H moie~yO Suitable epoxides include
26 aliphatic, cycloalipha~ic and aroma~ic epoxides. These
27 epoxides may contain o~her substltuen~ ~unc~lonal groups
28 such as an es~er group~ an unsa~ura~ed linlcage or a chlor~
~ ine substitu~nt and similar substi~uent groups which will
not adversely affect the quenching process. Generally
31 speaking, the suitable epoxides will have a carbon atom
32 range of rom about-2 to 20 carbon atoms. Of particular
- 7
. . , ~.
~ 6 S ~
l utility in the practice of the present invention are
2 epoxides having 2 to 8 carbon a-toms such as ethylene
3 oxideg propylene oxide, 1,2-epoxybutane and the like.
4 Examples of other suitable epoxides are 3,4~epoxy~1-
butene; 1,2,3,4~diepoxybutane; 1,2-epoxycyclohexane;
6 1,2-epoxycyclopentane; 1,2-epoxy-2-met:hylpropane; 1-
7 chloro~2,3-epoxypropane, ethyl 2,3~epoxybutyrate;
~ l-allyloxy-2,3-epoxypropane; 2,3-epoxypropyl methacrylate;
9 1,2-epoxyethylbenzene (styrene oxide); alpha-methylstyrene
oxide; and similar oxira.ne containing compounds.
.
11 The epo~ide may be co~enlen~ly added in admix~
12 ture with the same sol~ent which was used in the prepara-
13 tion of the elastomers of that cemen~ such as a mixture of
l4 propylene oxide and ~luene9 the propylene oxide concen-
tration being about 20 to 30% by weight~ In the practice
16 o~ the present inventlong the epoxide is employed in a~
l7 least stoichiometrlc amounts to effect the passi~ation~ that
18 is, on an equimolar basis based on the molPs of reactive
l9 ox~rane groups presen~ re~a~ive ~o ~he moles of sulfona~ing
agent employedO Generally speaking9 ~he molar ratio of
2l epoxide~ based on ~he moles o oxirane groups, to sulfona-
22 ting agent is from about 1:1 to lO:l. Thus, only
23 relatively small quantities of epoxide are required in
24 order to effect the passivat-ion of the sulfonation reac-
tion.
26In the next step of the process, the sulfonated
27 and passivated low unsaturation elastomer is then emulsi-
28 fied into water in a neutralized orm. The neutralization
~ step may be carried out before or after emNlsion prepara
30tion. Generally, it is preferred to emulsify the product
3l irst and thereater carry out neutralization.
32As neutralizing agents are employed, weak bases
-- 8 ~
~ 6 S S
1 such as an or~anic amine or ammOniUM hydroxide. Particu-
2 1arly useful are ~he lower alkyl primary amines and aroma-
3 ~ic primary amines, such as e~hylamine, propylamine, butyl-
4 amine, phenylamine3 and the likeO O~her subs~ituted or-
ganic amines including seconda~y and tert-Lary amines are
6 also usefulO Exemplary neu~ralizing ag~nts are diethylamine,
7 ~rie~hylamine and others con~aining substi~uen~ groups such
8 as hydroxyl, chlorog carbonyl~ ether, thioether~ nitroso
9 and the likeO T~e term "we~k base" as used herei.n applies
to ammonium hyroxide and organic amines hav mg a PKb greater
11 than 3OOo
12 The ~inished latex may be subsequently treated
13 wi~h a s~rong base~ such as an al~al~ me~al or allcaline
14 earth met~l hydroxide in order ~o increase ~he ionic bond-
ing of the film cast from the la~exO The term 1'strong
16 base" is meant to re~er ~o metal compounds and organic
17 amines h~ving a pK~ value o~ less than 3O0. Exemplary are
18 sodi~tm3 potasslum3 barium and calcium hydroxides~ alkox-
19 ides, carbonates or amine compounds such as ~e~raorgano
arr~onium hydroxide, ~e~rame~hyl ~mmonium hydroxide or tri-
21 methyl ben~yl ammonium hydroxideO
22 Latex emulsions are prepared by combining approx-
23 imately equal quantities of the passivated cement, either
24 in neutralized or non-neutralized fOrm9 with water contain-
ing a suita~le quantity of a surfactant or emulsifying
26 agentO An advantage of ~he present in~en~ion is that sig-
27 nificantly reduced quantities o~ emulsifying agent are
28 effecti~e in preparing stable oilJin~water emulsionsO Here-
~9 tofore, in preparing latex emulsions from alcohol quenched
sul~ona~ed elastomer cements3 the amount of emulsifler
31 required was on the order of lO to 15 parts per hundred
32 parts of elastomer present in ~.he sulfonated cement solu-
6 5 ~
tion. In the pre.sent in~ention9 effectivc emulsiicat~on
and dispersion is achieved by employ;ng approximately 3 to
3 6 parts per hundred of anionic surfactan~ per hundred parts
4 of elas~omer presen~ in ~he cemen~ solu~ion.
Anionic emNlsifying agents are employed in pre-
6 paring the emulsion compositions of the present invention.
7 Particularly preferred are ~he sodiumg po~assium and a~mo-
8 nium salts of sulfated ethoxylated alkanols and alkylphenols
~ such as C8-C20 alkanols and alkylphenols9 wherein the alkyl
portion has 8 to 12 carbon atoms9 the alkanols and alkyl-
11 phenols containing about 1 to 10 moles of ethylene oxide
12 per moleO Of special utility in the practice of ~he pre-
13 sent inven~ion is the sodium9 pokassium or ammonium sulate
14 deriva~ive of ~he 4 mole ethylene o~de adduct of nonyl-
phenol. Also suitableg but less preferable, are other
16 anionic surfactants such as ~he sodium and po~assium Cg-
17 C18 alkyl sulfatesg sodium alkyl glyceryl e~her sulfonate
18 sulfonated fatty ester sal~s and similar anionic surfac-
19 ~an~s wherein the solu~lliz;ng groups are -SO4H or ~S03Ho
Other suitable anionic surfactan~s are the sodium~ potas-
21 sium or ammonium salts of fa~ty acids containing rom about
22 8 to 24 carbon a~oms, preferably ~hose con~.aining about
23 10 to 20 carbon a~omsO The fa~y acids can be ob~ained
24 from nat~ural sources such as coconu~ oil fat~y acidsJ soy~
bean oil fat~y acids9 tall oil fat~y acids, rosin aclds
26 and hydrogenated rosin acids as well as synthetically pre-
27 pared atty acids such as by o~ida~ion of petroieum frac- -
28 'cions. Particular examples of such fat~y acid carboxyla~e
~9 salts are sodium stearate9 sodium oleateg sodium palm~tate,
30 potassium ricinoleate, and the likel
3l After the latex emulsion is.prepared by admixing
32 the components with simple agitation, such as by hand
- 10 -
ss
1 mixing, it may be subjected to more thorough agitation
2 such as in a homogeniæer to reduce ~he par~icle size
3 and to more ~horoughly disperse the particles. The
4 raw emulsion is then stripped of excess water and
aromatic solvent under vacuum to produce a finished
6 latex con~aining about 20 to 70%, preferably about 40
7 to 65%, such as 60% by weight of solids, the balance
consisting essentially o~ water.
9 Finished latex compositions prepared in
lo accordance with the present invention are characterized
11 as having excellent tensile properties. They are useful
12 as binders or nonwoven fabrics, as adhesives, in paper
13 coa~ing operations, and as overdips or highly unsatu-
14 rated rubber parts.
The invention is urther illustrated by the
16 following examples.
17 ;EXAMPLE 1
18 Ace~yl sulf~e was prepared by add~ng lloO ml of
19 sulfuric acid dropwise in~o 37O7 ml of acetic anhydride
while cooling the anhydride in an ice ba~hO '~he mix~ure
21 was stirred for an hourO
22 A butyl rubber cement was prepared by dissolving
23 EXXON BUTYL 268 in toluene so as to prepare a 16% by weight
24 solution. EXXON BUTYL 268 is a copolymer of isobutylene
(98.5 mole %) and isoprene (1~5 mole %) having a viscosity
26 average molecular weigh~ of 450,000 and a Mooney Viscosity
27 (ML 1~3 @ 260Fo) of 55. To 625 gr~ms of this cement
28 ~con~aining 100 grams of bu~yl rubber) was added 6.47 ml
~ of the acetyl sulfate prepared above. This mix~ure was
stirred for an hour and then 2.5 gram~ of propylene o~ide
31 m~xed with 10 grams of toluene were addedO A sample of
32 the cement was removed, the sample wa~ neutralized with
6~
ethylamine and then precipi~ated wit:h acetorle. The sample
2 was dried in a vacuum oven overnight at SQC~ and there-
3 after analyzed and found ~o con~aln 0064 wt. % sulftlr.
4 300 grams of the sulfonated quenched cement was
s slowly added to 300 grams of water containing lO grams of
6 the sodium sulfate der~vative of the 4 mol eth~lene o~ide
7 adduct of nonylphenol.~ sold as "Alipal CO 433" (a 29~7 wt.
8 % active surfactant~. ~he mixture was homogenizeclJ neutra-
9 - lized with 5 grams of ~mmonium hydroxide and excess water
and toluene was strlpped under vacuum using a rotary evap~
11 orator to produce a latex wi~h 55 w~0 ~/0 solids.
12 To evaluate the product's s~ability, a sample of
13 this la~ex at 40% solids was sheared in a Hamil~on Beach
14 mixer at 19~000 rpm for 30 minu~es while heated at 180F.
ls The coagulum ~lounted ~o 0O24 w~o %o
16 A sample of the finished latex prepared as des-
17 cribed above was ad~usted tG pH 9O5 with sodium hydroxide.
18 A film was cas~ from ~he la~ex and dried overnight at room
19 temperatureO I~ was fur~her dried in an oven a~ 170Fo
for 4 hours and ~:hen v~c~un dried overnigh~ a~ 50Co The
21 ilm had ~he following ~ensile propert:iesD
22 S~reng~:h a~ 100% ~:longa~ion 85 psi
23 S~reng~h a~ 500% Elonga~ion200 psi
24 Tensile S~rength 2700 psi
Elonga~ion a~ Break 1040
26 EXAMPLE 2
27 This example demonstrates ~he effect of ~arious
28 levels of propylene oxide quench on latex forma~Lon,
29 A series of experiments were done ln which the
quan~i~y of propylene oxide was v~ried. In each lexperimen~
31 a cemen~ con~aining lO0 gO of butyl rubber was sulfonated
32 with 6.5 ml ~24 mmoles) o~ acetyl sulfate using the
~ 6 5 ~
l procedure and materials described in Example 1. The
- 2 sul~onated cements were quenched with varying amounts
3 of propylene oxide as shown in Table 1. Each quenched
4 cement (300 g) was addecl to a solution of 300 g. oE
water containing 10 g. of "Alipal C0-433" as described
: 6 in Example 1. The results are shown in Table 1.
- 13 -
'`6~5
rO s ~
Q~
i ~
X
u~ ,~
U~ O
U~ ~1 U ~ ~
~1 ~ ~ ~1 o o o a) ~ O
~ ~ z æ z~ o~ z
U~ ~ ~ ~ U ~
a~ Q) ~ ~ o o
P~ ~ ~
~ a ~ ~
. - ~ ~ a) O u~
a) o
" ~ o
rr) t~ 3 h ~ ~ h
O ~ 0 0 ~ rl O
~r/
ox ~ a) . . -
O a) ~
~ p~ d
p~
P~
~0 ~ :~
~I h O
P~ O
O ~
~1 0 ~ ~ 1~ l O O
g o
. a~ ~ J~
~1 O r-l
. S~
~ ~ ~d~
: ~ ~ ~0
r~ ~ ~ 0
O ~
~r~ r~ rS td
o a~
Q) ~ ~3~ r~ C ~ r~
# ~ P` O u~ o
r-~ ra
c~ ~ O
P~ .
O
~i ,~ D ~ .
~ . ~
~4
14
X~MPLli 3
2 This example illustrates ~le use o~ a relati~ely
3 low level of emulsifying agentO A latex was prepared by
4 adding 300 g. of the quenched sulfonated cement o~ Example 1
~o a solu~ion of 4 phr of "Alipal C0~-433" (6 0 7 g. o 29 . 7%
6 active matexial) 1n 300 g. of distilled wa~erO This is 4
7 parts of emulsifier per hundred parts of elas~omer present
8 in the cemen~ solution. An oil~in~ ter emulsion easily
9 ~ormedc This emulsion was homogenized with no di~ficul~y
in an Ef~enback Homo Mixer for 3 minO at 40 volts with the
11 deflector plate Up9 3 min. at 110 volts with tlle deflector
12 pla~e up, and 5 minO at llO volts with the deflector plate
13 closedO
14 EXA
Acetyl sulf~e was prepared by dripping 11.0 ml
16 of sulfuric acid into 37O7 ml of acetic anhydride while
17 cooling the acetic anhydride in an ice bathO l~e mixture
18 was stirred ~or an hourO
19 An EPDM elas~omer cement w~s prepared by dissol-
ving an EPDM ha~ing an ethylene conten~ of 51 wt. %, an
21 ethylidene norbornene eontent of 9 wt. ~/0 and a Mooney vis-
22 cosity of 50 at 260F. in toluene. The EP~M elastomer
23 concentration was 10 wto %. To 1000 gO of this cement
24 (100 g. of elastomer) was added 4.7 ml of acetyl sulfate
prepared above. The cement immedia~ely turned dark brown
26 and was stirred for an hourO I~ was qu2nched with 2.5 g.
27 of propylene oxide in 10 ml o tolueneO The cement returned
28 . to its original amber color in about 5 min. I~ was stirred
29 for an additional one half hour.
3U The sulfonated and quenched cement (500 g~ was
31 poured into a mixture of 500 g. of dlstilled wal:er and 10.9
32 g. of "Alipal C0-433'7 ~27.4% active)~ r~is is equi~alent
- 15 -
i5~i
1 to 6 phr emulsi~ier per h~ndred p~rts o elas~omer present
2 in the solu~ionO An oll~ln~wa~er emulsiGn fonmed wl~h no
3 dif~icu1tyO This emulsion was ~omogenized using an ~ffen-
4 back Homo-Mixer for 5 min~ at 40 vol~s with the de1ector
plate UPJ 5 minO at 110 volts wit.h thle deflector plate up,
6 and 5 minO at 110 vol~s wi~h ~he defl~ec~or pla~e downO
7 Sodium hydroxide ~5 gO in 10 ml of water) was addedO The
8 resulting latex had an ~erage p~r~icle size of 1~ . The
9 latex had excel~ent high tempera~ure mechanical stability
with only 00 36~/o coagulum after shearing 30 minO in a HamiL~
11 ton~Beach mixer at 19,000 rpm while being heated ~o 180F.
12 Toluene and excess wa~er were vacu~m stripped
13 from the emulsion using a ro~ary evapora~or to give a latex
14 having 3606% solidsO This latex had excellent mechanical
stability gi~ng only 003~/0 coagulum when stirred at room
16 tempera~ure or 30 minO in a Hamllton~Beach mixer at 199000
17 rpmO A ilm was cast: from the finished latexO A~ter dry-
1~ ing the film had the foll~wing t:enslle propertieso
19 Strength a~ 100% Elonga~lon 115 psi
Strength at 500~/0 Elongation 170 psi
21 Tensile Streng~h 775 psi
22 ElongatiQn at Bre~ 700%
~3 E MPLE S
24 This example demonstr~tes the use of ethylene
25 oxideO Acetyl sulfate was prepared by dripp;ng lloO ml of
26 sulfuric acid into 37O 7 ml of ace~lc anhydride while cool-
27 ing the ace'cic anhydride in an ice bae:hO The mlxture was
28 stirred for an hourO
29 A bu~yl rubber cement was prepared by dlssolvi.ng
EXXON BUTYL 268 in toluerleO The butyl nlbber was 16 w~O %.
31 To 625 gO of thls cement (100 gO of rubber) was ac1ded 6. 5
32 ml of acetyl sula~e prepared as described above~ This
~ 16 -
5 ~
l mixture was s~irred or one h~lf hour, Eth~lene oxide (3
2 ml, 206 g) was added to quench the sulfonation reaction,
3 A sample was removed and neutra1ized with ethyl amine. The
4 rubber was preclpi~ated with acetone, dried in a vacu~un
oven and analyzed for sulfurO ~esults 007 wto % S~
6 The ethylene oxide quenched cemen~ (600 g) was
7 mi~ed wi~h G00 gO of dis~illed wa~er con~aining 21.9 g. of
8 "Allpal C0-433" (2704% active) which is 6 phr emulsi;er
g per ~undred par~s of elas~omer presen~ in solu~ionO An oil~
~n-wa~er em~lsion easily ~ormed~ This emulsion was homo~
ll genized with an Effenback Homo~Mixer for 3 mlnO at 40 volts
l2 with the de1ector pla~2 Up, 3 minO at 110 volts wi~h the
deflector pla~e up, and 5 minO at 11~ vol~s with ~he de-
flector plate downO Ammonium hydroxide (10 gO o~ 28 wto
% ma~erial) was added ~o ~he emulsionO Toluene and excess
16 water were removed with a rotary evaporator to g~ve a la-
17 ~ex with 5207 w~0 % solldsO The la~ex had an average par-
18 ticle size of ~1 micrcnO fhe la~ex had only 000002% co-
agulum when sheared for 30 minu~es at 19,000 rpm in a
Hamilton-Beach mixerO
21 ~
22 This is a comp~rative eæample o demonstra~e the
23 unsuitability o~ higher alcohols as quenching agents for
24 the sulfonation of low unsaturation elastomers from which
a latex is subsequently preparedO
26 Ace~yl sulfa~e was prepared by dripping 11,0 ml
27 of sulfuric acid in~o 37.7 ml of acetic anhydride while
28 cooling the acetic anhydride in an ice bathO The mixture
29 was s~irred for an hour,
A butyl rubber cement. was prepared by dissolving
31 EXXON BUTYI. 268 in tolueneO Th2 butyl rubber was 16 wt. 7
32 To 313 g. o~ the cement (50 g~ o:E r lbber) w~s added 3. 2S
- 17 -
.. . .
ss
1 ml of ~he ace~yl sulfate prepared above. This mixture was
2 stirred for one half hcur. 1 Octanol (31 g.~ b.p. 194C.)
3 was added and allowed to stlr for 1/2 hrO
4 The sulfonated cement (345 g.) whlch had been
quenched with l~oc~anol was slowly added ~o a mixture of
6 345 g. wa~er9 31 g. of l~octanol and 27.4 g. of "Alipal CO-
7 433" (27.4% active)O This mix~ure ormed a r~w enrulsion
8 eas~ly. It was homogenl~ed with an ~ffenback Homo-Mlxer
9 for 3 minO at 40 volts with the deflec~or plate up) 3 min.
at 110 volts with the deflec~or pla~e up followed by 3 min.
11 at llO volts wi~h ~he deflec~or pla~e downD Ammonium ~y-
12 droxide (5 ~. o~ 28% solu~ion) was added ~o ~che emulsion~
13 Excess ~oluene and wa~er were removed by s~ripping under
14 vacuum with a ro~ary evapora or. The emulsion coagulated
15 ~t about 21% solidsD
o 18
.. , .. ,.. ,. . ,.. . ,. ... ,, .. ~ '. , - ' ~ - ' " ' ,L?'
