Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
I
WO 90/09236 :~ PCTl~P90/00175
~~~~~3~~a
finder for liquids
A frequently occurring problem involves the binding of
spilled, environmentally hazardous liquid substances in such a
way that deeper penetration into the soil or flowing into the
sewage system or rivers, which means polluting and endangering
groundwater and surface water, can be avoided.
known conventional binders for local limitation of
contamination are sand, peat, sawdust or the like.
Mixtures of alkali metal or alkaline earth metal
carbonates with kieselguhr and iron oxide are known as so-called
chemical binders, in particular by fire brigades. Other known
binders for oils are plastics foams of, for example, poly-
urethane,, in particular milled PV foams, condensates based on
ghenol/formaldehydefsulfuric acid and, for example, fibers and
mats of polyethylene.
So-called superabsorbers are also known for binding
aqueous liquids.
All systems currently used have disadvantages, some of
which are serious. Thus, for example, binders which contain
carbonates are completely unsuitable for use in acidic solutions
since they can even react explosively by elimination of C02. Tn
the case of improper handling or the use of the incorrect binder,
damage may even be extended and made worse. All good hinders for
aqueous solutions have insufficient binding power for nonaqueous
solutions, while virtually all good binders for nonaqueous
solutions have insufficient or. no absorptive capacity for aqueous
systems.
Another disadvantage of some known binders is their low
density, which causes them to float on the liquid to be absorbed
ar adsorbed, sa that they have first to be stirred in mechani-
cally in order to display their full activity. Furthermore, such
products tend to produce large amounts of dust, with the result
that, on the one hand, the personnel deployed are exposed to
greater dangers and, on the other hand, mater9_al which is already
slightly contaminated is blown by the action of the wind and
contamination over a wide area can therefore occur.
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WO 90/09236 ~ ~ t~ ~ j ~ ~ PCT/~P90/00175
The most serious disadvantage of all binders according to
the prior art .for liquid media is therefore their insufficient
suitability fox universal use.
It is therefore the object of the present invention to
provide a binder for liquids which does not have the stated
disadvantages, in particular can be universally used and rules
out incorrect handling.
This object is achieved, surprisingly, by a binder which
contains crosslinked, hydrogel-foaming polymers and compounds
with a large surface area and/or a capillary and/or fibrous
structure.
Crosslinked, hydrogel-forning polymers are preferably the
polymers kno;vn under the name "superabsorbers".
Preferred superabso~.~bers are those which are formed by
polymerization of olefinic monomers, such as, for example,
acrylic acid, acrylamide, methacrylic acid, methacrylamide,
vinylsulfonic acid, malefic acid, fumaric acid, crotonic acid, 2-
acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-
methylpropanephosphonic acid and vinylphosphonic acid and/or
20', their half--esters and/or salts of the stated acids, in the
presence of up to 2~ by weight of polyfunctional epoxides,~or
monomers having at least two olefinically unsaturated double
bonds, such as, for example, bisacrylamidoacetic acid,
tri.methylolpropane triacrylate and/or tetraallyloxyethane.
Particularly preferred superabsorbers are those which are
prepared by polymerization of acrylamide and/or acrylic acid
and/or a salt thereof, izi the presence of up to 2~ by weight of
bisacrylamidoacetic acid, trimethylolpropane triacrylate and/or
tetraallyloxyethane.
Compounds with a large surface area and/or a capillary
and/or fibrous structure may be inorganic or organic, of natural
origin or synthetically produced.
Preferred compounds of this type are, for example,
kieselguhr, peat, sawdust, wood meal, wood wool, straw, paper
fibers, pulp or plastics in fibrous or milled form, such as, for
example, polyethylene fiber filler, polyethylene fluff or milled
polyurethane foam, and the stated substances can also be used as
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WU 90109236 ~ ~ ~ ~ ~ ~ ~ PCT/~1~90/00175
a mixture with one another.
The binders according to the invention usually contain
the superabsorber and the compound with a large'surface area each
zn amounts of 10-905 by weight, preferably 30-70~ by weight.
The binder according to the invention may optionally
contain further additives. The addition of up to 30~ by weight,
particularly preferably up to 20~ by weight, of a polyglycol is
particularly preferred, with the result that possible dust
formation by the binder can be avoided, which is advantageous
particularly during use in the open air in a strong wind.
Preferred polyglycols are those which have a melting
point of less than 20°C, in other words essentially polyglycols
having a molecular weight of up to 500.
2f the binder is to be used for scattering on traffic
1S areas, up to 30=~ by weight, particularly preferably up to 20~ by
weight, of coarse-particled, sharp-edged materials, such as sand,
chips or, preferably, crushed expanded clay, are preferably
admixed as abrasive material to increase the resistance to
skidding.
The binders according to the invention can be prepared by
mixing the individual components in 'the desired ratio.
If the stated method only results in insufficient
homogeneity of the product, or the compound with a large surface
area has a very low bulk density, this too can be mixed in an
appropriate amount with the mechnically comminuted, water-
containing superabsorber crude product which was obtained by gel
polymerization, even before said product is dried, and the
mixture is kneaded, dried and milled and optionally further
components are admixed.
Finally, the binder according to the invention can also
be prepared by mixing the compound with a large surface area with
the monomer solution of the superabsorber, carrying out
polymerization by the process of gel polymerization and drying
and milling the product obtained, and optionally admixing further
components.
The binders according to the invention can be used in
various forms for binding liquid media, for example in pure form
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W~ 90/09236 ~ ~ ~~ ~ ~ ~ pCT/E~90/00175
by dumping to form a wall, by scattering in or on, which can be
effected manually or with the aid of a gritter, by blowing or for
sealing barrier layers. However, they can also be used in incor-.
porated form, such as, for example, in nonwovens, woven fabrics
or perforated films which are bag-, strand- or sausage-shaped, or
in large, perforated, quilt-like mats, or pressed into pellets.
It is also particularly advantageous to blow the binders
according to the invention onto the liquid to be bound, with the
aid of a pressure container, such as, for example, can con-
veniently be carried during transport of hazardous materials.
The use forms described can also be used without loss pf
effectiveness where there is wind activity and independently o.f
temperature influences.
The binders according to the invention are universally
suitable far binding both aqueous, acidic or alkaline liquids and
nonaqueous liquids or mixtures thereof with one another and
display their binding activity even when they are simply
scattered without mechanical aid. It may also be regarded as
particularly advantageous that spent binder can be very easily
removed from the surface onto which it has been scattered,
without leaving residues. This can be effected manually or with
the aid of industrial vacuum cleaners or suction pumps.
In contrast to conventional binders, aqueous liquids
cannot b~ pressed out of the binders according to the invention
by mechanical effects.
After removal of spent binders according to the inventipn
from contaminated soil, a further amount of chemicals can be
removed from the soil by further scattering of fresh binder. It
is thus possible, with the binders according to the invention, to
carry out long-term treatment even of large areas if the latter
are additionally covered with water-impermeable films. In this
way, it is also possible to remove radioactive substances from
surfaces and soil.
The binders according to the invention can also be used
for building up a vapor barrier. In other words, when scattered
on toxic or strongly smelling media, less hazardous or odorous
vapors escape than in the case of known binders, so that the
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WO 90/09236 PCT/EP90/00175
personnel deployed can work closer to the endangered site and are
in less danger. This also applies in particular to hydrochloric
acid and other substances which fume strongly in the air.
The binders according to the invention are not fire-
s promoting. Superabsorbers have a flashpoint of over 200°C, while
the compounds with the large surface area are for the rtdost part
nonflammable.
The binders according to the invention constitute a
considerable advance in the prevention or restriction of damage
caused by spilled liquids.
The Examples which follow illustrate the present
invention:
Example 1
60 g of kieselguhr and 40 g of ~Tylose VS 3746
(superabsorber based on polyacrylater aTylose is a registered
trade mark of Hoechst AG, Frankfurt am Main) are mixed until
complete homogeneity is obtained.
Example 2
Example 1 is repeated using 55 g of kieselguhr, 36 g of
~Tylose VS 3746 and 9 g of polyethylene glycol 200.
Example 3
635 g of water and 180 g of sodium bicarbonate are
initially taken in a vessel well insulated with foamed plastic
material and 240 g of acrylic acid are metered in at a rate such
that the reaction solution does not foam over, said solution
cooling down to a temperature of 10 to 8°C. 1.5 g of sodium
diisooctylsulfosuccinate and a solution of 2 g of GENApOL~ OX 130
(GENAFOL~ is a registered trade mark of Hoechst AG, Frankfurt) and
2.5 g of l,l,l-trimethylolpropane triacrylate are then added.
The initiators, a redox system consisting of 0.2 g of 2,2'-
azobisami.dinopropane dihydrochloride, dissolved in 2.5 g of
water, 0.6 g of potassium peroxodisulfate, dissolved in 20 g of
water, and 0.05 g of ascorbic acid, dissolved in 10 g of water,
are added in successian at a temperature of 8-10°C and the mixture
is stirred thoroughly. The reaction solution is allowed to stand
without stirring, the temperature increasing to 80°C and a solid
gel being formed, as a result of polymerization which occurs.
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WO 90/09236 ~ ~ ~ ~ ~ ~ ~ PCT/EP90/00175
1,000 g of the polymer gel thus obtained are mechanically
comminuted, 245 g of polyethylene fluff are added and the mixture
is kneaded in a kneader to give a homogeneous mixture and then
dried at temperatures above 80°C and milled.
Example 4:
Example 3 is repeated, 1,000 g of the polymer gel being
replaced with 300 g of pulp fluff.
Example 5:
Repetition of Example 3 using 1,000 g of polymer gel and
200 g of milled polyurethane foam.
Examz~le 6:
Repetition of Example 3 using 800 g of polymer gel, 350 g
of polyethylene fluff and in addition 100 g of polyethylene
glycol. 300.
Example 7:
' Repetition of Example 3 using 1,000 g of polymer gel and
280 g of polyethylene fiber filler having a fiber length of 1-5
am.
Table 1 demonstrates the universal applicability of the
binders
according
to
the
invention
under
conditions
in
practice,
in comparison with known binders. Th~ following symbols are
used:
-E+ = very good
+ - good . .:
0 -- possible
- - poor ,
-- cannot be used
The following binders axe compared:
A - Risselguhr, commercially available
B - Pulp fluff, commercially available
C - ~Rench-Rapid, from Rench Rapid GmbH, Rechen; based on
phenol/formaldehyde/sulfuric acid condensate
D - ~Ntetax 1713, from Chemital GmbH, Frankfurt/M.; ..
E - ~Ekoperl 99, from Eduard Michels GmbH, Essen; (~ietax and
~Ekoperl = mixtures based on carbonate/kieselguhr/iron
oxide)
F - ~Tylase 3746, from Hoechst AG, Frankfurt/Main;
G - Mixture according to the invention (Example 2)
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~~~.~~Je~~
WO 90/09.236 PCT/EP90/00175
Table 1
A B C D E F G
Can be~manually scattered - - + o -H + ++
Scatterability, gritter - -- o - o + ++
Blowing by pressure container-- -- -- -- -- ++ -3-t-
Behavior in wind - - - - + ++ -+-+
(Dust formation and associated
increase in area and endanger-
ing of personnel deployed)
Binding of harmful substances
from surfaces and out of o - 0 0 0 + a-t-
soil
Formation of a vapor barrier- - o - - + -!-+
Damming of liquids - - - - o -E +-~-
Absorptivity for aqueous , - -- + ;-
liquids
Absorptivity for nonaqueous + -~ ++~~ ;- o - ,
liquids
Absorptivity for dripping o - - o o + -r-f-
liquids with high specific
gravity
Behavior to oxidizing agents+ --b~ + o ++ ++
--b~
Behavior to acids or alkalis++ - -H~ pd~ pa y..e)~f)
Nonflammability ++ -g~ -h~ ++ ++ -t-o-++
Removal of spent binder:
manually - + + - - + ++
with industrial vacuum
cleaners - + o - - +
with suction pumps o - o o - o +-t-
