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Патент USA US3042642

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Unite States Patent (‘Y "ice
3,042,633
Patented July 3, 1962
'5
2
3,042,633
gives ?ocs of reduced size. After the latex has been co
agulated to a ?ne ?occulate, an aldehyde resin is incor
porated in the aqueous medium of the slurry of the rubber
3.
RUBBER rovvnnn
Woodrow W. White, ()xford, Conn, assignor to United
States Rubber Company, New York, N.Y., a corpora
tion of New Jersey
N0 Drawing. Fiied Apr. 29, 1957, Ser. No. 653,745
12 Claims. (‘-Cl. 260-3)
?ocs and the resin is precipitated therein to form a water
insoluble coating on the ?ocs. The ?ocs may then be de
watered as by ?ltering, and dried as in conventional rub
ber practice. The aldehyde resin may be phenol-aldehyde,
resorcinol-aldehyde, urea-aldehyde, melamine-aldehyde or
aniline-aldehyde resin in which the aldehyde is formalde
This invention relates to improvements in rubber pow
der for incorporation in the bituminous binder used in 10 hyde or acetaldehyde. An aqueous solution of the re
atant other than the aldehyde may be added to the aque
building roads, and for other purposes.
ous slurry of the rubber ?occulate followed by an aqueous
In conventional road building practice, hot bituminous
solution of the aldehyde or an aqueous solution of a mix~
binder (asphalt or road tar) is mixed with the aggregate
ture of the two may be added to the aqueous slurry. The
at a pug mill, generally in amount from 3 to 15% on the
weight of the aggregate, and the mix is then transported 15 molar ratio of reactant other than aldehyde to aldehyde
is generally from about 1:0.75 to 1:2.0. The mixture of
to the paving site, or the dry aggregate is ?rst laid on the
the resin reactants in aqueous acid medium of the slurry
road and the hot bituminous binder is then sprayed on
of the rubber ?uocculate is agitated for a short time, e.g.
the aggregate. In these operations the binder is at a tem
from 1/2 to 3 hours at temperature from 50° C. to 100° C.
perature of 250° F. to 400° F. (generally 250° F. to
350° F.).
20 for formation of the water-soluble resin after which the
pH is raised’ to 8 or above by the addition of dilute alkali.
Rubber powders prepared directly from natural and
As the pH is raised, the resin which has been ‘formed in
the acid phase is precipitated and deposited on the surface
of the rubber ?ocs giving a product which is non-tacky
synthetic rubber latices have been incorporated in the hot
bituminous binder used with the mineral aggregate in
forming paving compositions, generally in amounts to give
1 to 15 parts of rubber per 100 parts of bituminous binder. 25 because the ‘particles are coated with a brittle non-tacky
resin. The resulting particles aredewatered as by ?lter
ing, and dried, giving a ?ne free-?owing powder. The
However, such rubber p wders do not flow easily and
have a tendency to sinter in storage and thus make di?i
amount of resin may be from 2 to 30% of the ?nal coated
cult their handling and measuring and their gradual addi
particles with the preferred level being 10 to 16%. The
tion to the hot melt of bituminous material.. One method
of attempting to overcome this di?iculty has been to’vul 30 dried resin coated rubber particles may be in the range
from 10 to 200 mesh, and generally will be in the range y
canize the latex before producing the rubber powder. An
from 30 to 100 mesh. The amount of the thus prepared
other method has been to coprecipitate the rubber in the
resin coated rubber powder that is mixed with the hot
latex with an equal amount or more of ground inert
bituminous binder is that which gives from 1 to 15 parts
mineral ?ller. These methods introduce other disadvan
tages. The vulcanization reduces the compatibility of the 35 of rubber per 100 parts of the asphalt or road tar binder,
whether added as such in the pug mill with the hot ag
rubber with the bituminous binder. The large amount
gregate and the binder, or mixed with the hot binder be
of ?ller increases the extraneous material which is shipped
fore introduction into the pug mill, or mixed with the hot
about and has a tendency to settle out when added to bulk
binder before spraying on the rolled hot aggregate. As
quantities of the bituminous binder.
By the present invention, there is provided an improved 40 above described, the temperature of the binder in these
operations is from 250° F.‘ to 400° F. (generally 250° to
rubber powder which is free-?owing and non~sintering
350° F.).
under storage conditions and which is readily and uni
The latex may be a natural or synthetic rubber latex.
formly dissolved or dispersed in hot bituminous material.
According to the present invention, the individual par
ticles of rubber powder prepared directly from latex are
coated with an aldehyde resin which imparts the free
The synthetic'rubbcr latex may be a so-called butadiene
polymer synthetic rubber latex, i.e. an aqueous emulsion
?owing properties to the crumbs, and permits ready dis
ple, butadiene-1,3, 2-methylbutadiene-l,3 (isoprene), 2
solution of the rubber in the bituminous material. Such
resin coated powder may be mixed with the hot bitumi
nous binder for the aggregate in road building generally
in amount from 1 to 15 parts of rubber per 100 parts of
bituminous binder. Mixtures of bituminous material and
the resin coated powder in amount up to 25 parts of rub
ber per 100 parts of bituminous material may be used as
expansion joint ?llers in road construction, and as lami
nating adhesives in making paper to paper and paper to
metal foil laminates. The rubber powders with the resin
coating on the individual rubber particles may be used
chlorobutadiene-1,3 (chloroprene), 2,3-dimethylbutadi
directly in molding and extrusion processes to'give ?nished '
rubber articles.
.
polymerizate of one or ‘more butadienes-l,3, for exam
cue-1,3, piperylene, or a mixture of one or more such
butadienes-lfa" with one or, more other polymerizable
compounds which are capable of forming rubbery co-'
polymers with_butadienes-1,3, for example, up to 70%
by weight of such mixture of one or more compounds
which contain a CH2=C< group where at least one
of the disconnected valences is, attached to an electro-.
negative group, that is, a group which substantially in
creases the electrical dissyrnmetry or polar‘ character of
the molecule; Examples of compounds which contain
a CH2=C< group and are copolymerizable with butadi-- '
60 cue-1,3 hydrocarbons are aryl ole?nes, suchv as styrene,»
which may be unvulcanized or vulcanized or which may
vinyl toluene, alpha methyl styrene, chlorostyrene, di
chlorostyrene, vinyl naphthalene; the alpha methylene
contain vulcanizing ingredients, softeners, extenders or
?llers, emulsi?ed or dispersed therein,_is ?occulated in the
carboxylic acids and their esters, nitriles and amides, such
as acrylic acid, methyl acrylate, methyl .methacrylate;
In carrying out the present invention, the rubber latex
conventional manner to form ready ?lte'rable ?ocs. For ex
acrylonitrile, ,methacrylonitrile, methacrylamide; methyl
ample, the latex may be creamed by addition of a solution ~
vinyl ether; methyl vinyl ~ketone; vinylidene ._chloride;
of a monovalent salt, such as sodium chloride, and then > vinyl pyridines; alkyl vinyl pyridines. ‘Common com
?occulated with dilute acid, such as sulfuric, hydrochloric I '
mercial synthetic rubber ‘latices ‘arelaticesof GR-S (co
or acetic acid, or by dilute solutions of multivalent salts.
polymer of a major proportion ‘of butadiene and a minor
of strong acids, such as calcium chloride or aluminum sul 70 proportion of styrene), Paracril (copolymer of a major
fate. The addition of up to 20 parts of sodium lignate
proportion of butadiene and a minor proportion .of
per l00 parts of rubber of the latex before ?occulation
acrylonitrile); and neoprene (polymerized chloro-Z-butae
4
. diene—1‘,'3). Such latices may be compounded with sof
in admixture with previously flocculated rubber latex
' teners, extenders and ?llers by adding emulsions or dis
- particles onto said'?occulated rubber latex particles, said
persions of the same to the latex before ?occulation.
.For example, asphalt and tar softeners and extender oils
.such asheavy petroleum fractions may be added to the
"latex as emulsions generally in amount up to'one-half
rubber being selected from the group consisting of natural
rubber and synthetic rubber emulsion polymerizates of
material selected from the’ group consisting of butadienes
71,3,and mixtures of butadienes-1,3 with compounds which
the weight of the rubber. Similarly inert ?llers, such as.
contain a CH2=C< group and are copolymerizable with
‘silica maybe formed in situ'in the latex, or inert ?llers
.such as‘ silica and carbon black may be, added to the
butadienes-1,3.
'
.
t
'
2. A free flowing dried resin coated rubber powder the
latex as dispersions generally in amount up to one-half 10 particles of which are 1010 200 mesh size and are coated
'of the weight of the rubber.
'
'
with aniline-formaldehyde resin, said resin being precip
r
The following'illustrates the invention. 7 All parts and ’
percentages referred to herein are by weight.
.
itated from asoluble state in an aqueous acid medium
in admixture with previously ?occulated rubber latex
144. pounds (40 pounds dry'weight) of a latex of a
particles onto said?oeculated rubber latex particles, said
copolymer of 175 ' parts of butadiene and 125 parts of. 15 rubber being selected from ‘the group consisting of natu
styrene were stabilized to'oxidation by the addition of
ral rubber and synthetic rubber "emulsion polymerizates
1189, pounds (0.6 pounds dry Weight)’ of? an aqueous ' , ‘of material selected from the group consistingof butadi
emulsion of condensed diphenylamine acetone reaction . , enes-1,3 and mixtures of.butadiezies-LS,withcompounds
A solution of sodium lignate which had been
' preparediby dissolvingf0.82 pounds of sodium hydroxide
which containa CH2=C<jgroup and are copolyrneriza-'
' product.
20' ble
in;l0 pounds'of water and'dissolving 2.07 pounds of
with butadiene's-Lél.l
'
l '
"
Y
-
3. A free ?owing :dried. resin coated rubber powder
the particles of which aIe'lO to 200 mesh size and are
coated with‘ resin selected from the group consisting of
.lignin (Indulin A) in the‘ solution was then‘ added. This
''mixture was creamed .with'320 pounds (24 pounds dry
phenol-aldehyde, resorcinol-aldehyde, urea-aldehyde, mel
. . weight) or a sodium chloride solution which was ad
justed to 'a pH of’ 10' with sodium hydroxide. iFloccula-r 25 amine aldehyde and aniline-aldehyde, resins in which the
tion was then accomplished under. vigorous‘ agitation, by
aldehyde is selected from the group consisting of formal- '
the addition of sui?cient sulfuric acidltetraethylene pentai . dehyde and acetaldehyde, said resin being in amount
mine solution (2 pounds sulfuric acid and 0.4 pounds of
from'2 to 30% by weight of the coated particles and
tetraethylene pentamine "to obtain smooth ?occulation
being‘ precipitated‘ from a solublei'state in an aqueous
per 38-pounds of water) to reduce the pH to 2. The ?oci
acid medium in'admixture with previously ?occulated
fculat‘e was" in very ?ne particles. "A solution containing
rubber latex particles onto said'?occulated rubber latex
3.3‘porin‘ds of aniline dissolved in l.9,pounds'of sulfuric
particles, said rubber being selected from the group con
' . acid and 74.8 pounds of water was then added followed
' sisting of natural rubber and synthetic rubber emulsion
bythe addition of l0v pounds (.4. pounds dry'weight') of 1 ' polymerizates of material's'elected from'the group con
7 210% formaldehyde. The mixture was then held under 35 sisting of butadienes-_l,3 and mixtures of butadienes-1,3
agitation at 140-150”
for one hour, ‘after which the‘ .with‘ compounds which contain a'CH2'=C< group and
pH was raised to 8 using a solution of sodium hydroxide.
are copolymerizable ‘with butadienes-l?q
The resin deposited on the‘ rubber ?ocs. The ?ne ?oc
'4. A' free ?owing dried resin coated rubber powder
culate was then ?ltered onto cheese cloth and dried over:
the particles of which are '10 to 2007me7sh’size and are
nightfat 170° F. 1 After drying the'iproduct wasfin the
form of porous ‘chunks which disintegrated’into very ?ne
coated with 'aniline-formaldehydefresin, said resin being
in amount from'2lt'o' 30%‘ by weight of the coated parti
free-?owing powderiof about 40 rnesh'unde'rv mild grind
ing ‘conditions.
i
'
'
‘
eles and‘being'precipitated from a soluble state in an
7 :aqueous acid'medium in ‘admixture with previously ?oc
'
‘
ree pants of'the fzhusv prepared‘. resin coated‘rubber .
. powder Were added to 97. parts of asphalt heated: to about
45
culated rubber latex particles onto said‘?oc'cul-ated rub
ber latex particles‘, said rubber being selected from the
350° in‘ a closed container equipped with an agitator. ‘ group consisting vof natural’ rubber and synthetic rubber
I The asphalt had a penetration value at 77°F. of 110-120 .
emulsion polymerizatesjof'nlaterial selected from the
(A‘.S.T;M.~ D5-52).' The rubber was completely dis
f group consisting‘ of butadienes-l? rand
of buta
. 7 ' persed in‘thew asphaltfgiving a smooth mix in three hours; ' dienes'-l,3 :with‘. compounds which contain a .CH2—_~,C<
'Such blend is useful as a binder “for the aggregate pin. 50 group . and are copolymer‘iizable with _butadie_nes-l,3.
'
road construction.
V 5.._The method of making free ?owing resin coated
rubber powder of particles‘of 10 to 200 mesh sizefrom
. latexi which comprises ?rst ?occulating'the latex and
l a "
'l‘wenty'p'aritsof the above resin coated rubber powder
‘were vadded'to $0'Iparts of asphalt at 3275*‘ F.‘ in an in
7te'rnal mixer of. the'Werner‘andjP?eidereritype; The
' asphalt had a penetration value at 77° F. of about 200 55
(A.S.T.M. D5,-5.2).’ The rubber was completely dis
pensed‘in the asphalt. giving a smooth mix in four hours.
V
of ‘phenol-aldehyde, resorcinol-aldehyde, urea-aldehyde,
. melaminegaldehyde and aniline-aldehyde resins in which
the ‘aldehyde I is selected from” the group consisting of
Such blend useful for ?lling expansion joints in paving’ ' formaldehydeqandr vacetaldehyde .on wthe-Wet 1109s to coat
" ‘construction’
by. pouring in "melted; conditionrbetwee‘n
thei'same, dewatering the coated rubber does of the ?oc
r 7
adjacent paving sections.
"
‘
60 culatedrlatex, and drying’, said 7 rubber being’ selected,
from thegroupiconsistinggof natural. rubbervand synthetic
Ingviewq of ‘thegmany changes and modi?cations that ,
.may be made without departing from the principles un-1 .
‘derlying the inventionkreference should be made to'the ,
rubber, emulsion polymerizates 'ofmaterial selected from
the group consisting of ibutadienes-l? and mixtures of
~appended‘claims 'for anunderstanding?of the scope of
.
the protection 'a?orded ‘the invention.
.
‘
, Having thus described
my invention-,what Iclaim
; fdesire-to'protect'wby Letters Patent is:
Y '
then depositing resin selected: from the group consisting
' ~
'butadienesjl? with ‘compounds which contain a
andq
' "
>';1.'Afree-?owing dried resinjcoated rubber. powder
"
.
a
group andiare copolymerizable" with butadienes-l?.
_6'. 'The'gmethodf of making ifr‘ee i?owing resin coated
'
the'particles'of Whichare 10'to 200 mesh size and are
rubber powder ofparticles of £10m 2001mesh'size from‘
coated
resin selected from; thepgrou‘p consisting of 70 latex which'tcomprises ‘?rst; ?occulating the latex and’ then
phenol; aldehyde, resoreinol-v- aldehyde, ’ urea - aldehyde,
depositing ranilinerfolfhqliildehyde ‘resin on the .wet does to
1, ainelamine-alde'hyde and‘aniline-ialdehyde resins in which ' coat the same, dewatering ,the'pcoated rubber ?oes of the
' the aldehyde is'_ selected from the'groupiconsistingrof ' , ?occulated latex,>and drying, saidJubber. being selected
formaldehyde andvacetaldehyde, saidresin being preeip» from ,the'group consisting of natural rubber and synthetic
itated from ajsoluble state in' an aqueous acid medium 75 rubber emulsion polymerizates iofwmaterial selected from
3,042,833
the group consisting of butadienes-1,3 and mixtures of
butadienes-1,3 with compounds which contain a CH2=C<
group and are copolymerizable with butadienes-1,3.
7. The method of making free ?owing resin coated
rubber powder of particles of 10 to 200 mesh size from
latex which comprises ?rst ?occulating the latex and then
depositing resin selected from the group consisting of
phenol-aldehyde, resorcinal-aldehyde, urea-aldehyde, mel
9. A composition comprising a blend of bituminous
material and a vfree ?owing resin coated rubber powder
as de?ned in claim 3, the rubber content of the blend
being from 1 to 25 parts per 100 parts of the bituminous
material.
10. A composition comprising a blend of bituminous
material and a free ?owing resin coated rubber powder
as de?ned in claim 4, the rubber content of the blend
being from 1 to 25 parts per 100 parts of the bituminous
amine aldehyde and aniline-aldehyde resins in which the
aldehyde is selected from the group consisting of formal 10 material.
11. The method of uniformly dispersing rubber in
dehyde and acetaldehyde on the Wet rubber ?ocs of the
bituminous material which comprises mixing with hot
?occulated latex to coat the same, dewatering the coated
bituminous material a free ?owing resin coated rubber
?ocs, and drying, said resin being precipitated from a
powder prepared according to the method of claim 5.
soluble state in an aqueous acid medium in admixture
12. The method of uniformly dispersing rubber in
with the ?occulated rubber latex particles onto said ?oc 15
bituminous material which comprises mixing with hot
culated rubber latex particles, said rubber being selected
bituminous material a free ?owing resin coated rubber
from the group consisting of natural rubber and synthetic
powder prepared according to the method of claim 6.
rubber emulsion polymerizates of material selected from
the group consisting of butadienes-1,3 and mixtures of
References Cited in the ?le of this patent
butadienes-1,3 with compounds which contain a CH2=C< 20
group and are copolymerizable With butadienes-l,3.
8. The method of making free ?owing resin coated
rubber powder of particles of 10 to 200 mesh size from
latex which comprises ?rst ?occulating the latex and then
depositing aniline-formaldehyde resin on the Wet rubber
?ocs of the ?occulated latex to coat the same, dewater
UNITED STATES PATENTS
2,277,941
2,314,181
2,610,158
2,700,655
Almy _______________ __ Mar. 31,
Winterkorn __________ __ Mar. 16,
Hall ________________ __ Sept. 9,
Endres et a1 ___________ __ Jan. 25,
1942
1943
1952
1955
ing the coated ?ocs, and drying, said resin being precip
2,845,397
Mills _____________ __‘..__ July 29, 1958
itated from a soluble state in an aqueous acid medium
2,857,351
Carrol ______________ __ Oct. 21, 1958
in admixture with the ?occulated rubber latex particles
FOREIGN PATENTS
onto said ?occulated rubber latex particles, said rubber 30
381,587
Great
Britain __________ _._ Oct. 7, 1932
being selected from the group consisting of natural rub
bet‘ and synthetic rubber emulsion polymerizates of ma
OTHER REFERENCES
terial selected from the group consisting of butadienes-1,3
Clinebell et al.: “A Survey on the Use of Rubber in
and mixtures of butadienes-1,3 with compounds which
Bituminous Pavements,” Rubber Age, volume 70, pub. ,
contain a CH2=C< group and ‘are copolymerizable with
October 1951, page 70.
butadienes-l,3.
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