Note: Descriptions are shown in the official language in which they were submitted.
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F ~l. E, ~ttt't~
~~.~.,°~~,~I~~~,~'1°1~'~ KM/by/ngb/W6N15.06.1998
-1-
A method of removing, organic liduids which pollute surface water
The present invention relates to a method of removing organic liquids,
particularly oil,
which pollute surface water, wherein a binding agent which binds the organic
liquid is
applied to the surface of the water and the binding agent is subsequently
removed with
the bound or absorbed liquid.
Oil slicks floating on water constitute a serious threat to the environment,
for
example. One particular problem is that even very small contents of oil poison
a
stretch of water and constitute a lethal hazard to fish and other forms of
life.
Therefore, when oil slicks such as these are removed, it is very important
that the oil
is removed practically completely and that the oil is eliminated very rapidly,
so that
the oil slick cannot spread, or can only spread to a slight extent.
1 ~ The removal of oil slicks is generally effected by applying a binding
agent which
absorbs oil to the surface of the water, and subsequently removing the binding
agent
together with the bound or absorbed oil. The substances which are generally
used as
binding agents are those with a high affinity for oil. such as special
plastics or
substances which possess a macroscopic pore structure. in solid or liquid
form. These
substances are applied to the surface of the water, whereupon the binding
agents bind
the oil to themselves or suck up the oil before they form a floating slick on
the surface
of the water which can then easily be removed.
Moreover, since the polymer itself is not dispersed in water or seawater, so
that oil
droplets floating in the water cannot be removed by the polymer, it is known
from JP
59-039 381 A that an aqueous dispersion can be produced which comprises the
polymer on the one .hand and water which contains alcohol as a solvent on the
other
hand, and which exhibits excellent dispersibility in water, so that the
polymer is also
present under the surface of the water in order to absorb oil there.
3O
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In practice, there is a multiplicity of different binding agents which are
used, and
which apart from the polymer may also contain other oil-absorbing
constituents, such
as sawdust, peat, cork and the like. Moreover, it is known that constituents
can be
added to the polymer which cause the oil to form lumps or similar agglomerates
(JP
~4-033 887 A), which can easily be removed.
As before, however, one problem with the removal of oil slicks such as these
is that
the oil spreads rapidly, particularly under the effect of wind and/or vigorous
wave
motion in the open sea, and that even a coherent slick of oil which has
already been
bound is driven apart.
The object of the present invention is accordingly to improve the method cited
at the
outset for the removal of organic liquids which pollute surface water so that
spreading
of the organic liquid can be prevented or can at least be reduced, and so that
the
1 ~ subsequent removal thereof, e.g. by suction, is facilitated.
This object is essentially achieved according to the invention in that in
order to
delimit a polluted surface area a solution or dispersion of a polymer or a
mixture of
polymers and a water-miscible and/or readily volatile solvent which has a
lower
?0 density than water is applied to the surface of the water. The present
invention
therefore relates to a method of removing organic liquids which pollute
surface water,
wherein in order to delimit a polluted surface area a solution/dispersion of a
polymer
or a mixture of polymers and a water-miscible and/or readily volatile solvent
which
has a lower density than water is applied to the surface of the water, wherein
a binding
agent which binds the organic liquid is applied before or after the
application of the
polymer solution/dispersion, and the binding agent is subsequently removed
with the
bound or absorbed liquid, wherein the polymers are biodegradable and are
selected
from aliphatic or partially aromatic polyesters, thermoplastic aliphatic or
partially
aromatic polyester urethanes, aliphatic or aliphatic-aromatic polyester
carbonates, or
30 from aliphatic or partially aromatic polyester amides.
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The invention is based on the concept of placing a barrier round a polluted
surface
area in order to hold the surface area together and thus to counteract further
spreading
of the pollutants. According to the invention, this ring-shaped barrier is
formed by
applying a polymer solution or dispersion to the surface of the water, which
solution
or dispersion spreads, along the pollution on the surface of the water with
the
formation of a closed ring due to its low density and its affinity for the
organic
pollutants. In the course of this process, the solvent becomes mixed with the
water or
evaporates, which results in the polymer being precipitated on the surface of
the water
with the formation of the desired ring-shaped barrier, which delimits the
polluted
surface area and holds it together so that the pollution is scarcely still
capable of
spreading.
The extent of the ring-shaped barrier substantially depends on the amount of
solution
/dispersion which is applied to the surface of the water, and is limited by
the
I 5 evaporation of the solvent or the mixing thereof with the water.
The polymer content of the solution/dispersion generally amounts to up to 50 %
by
weight (with respect to the total solution or dispersion). Higher
concentrations are less
suitable, because they are not sufficiently free-flowing. The polymer content
is
~0 preferably to 30 % by weight, particularly 5 to 10 % by weight.
In order to promote uniform ring formation, it is advantageous if the solution
is
applied as uniformly as possible to the surface of the water. This can be
accomplished,
for example, by spraying the solution on to the surface of the water.
The solution or dispersion preferably contains a biodegradable polymer or a
mixture
of biodegradable polymers, so that the solution/dispersion or the polymer
contained
therein can be disposed of without problems.
30 Suitable biodegradable polymers include aliphatic or partially aromatic
polyesters,
thermoplastic aliphatic or partially aromatic polyester urethanes, aliphatic
or aliphatic-
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aromatic polyester carbonates, or aliphatic or partially aromatic polyester
amides or
mixtures thereof.
The following polymers are suitable:
Aliphatic or partially aromatic polyesters formed from
A) aliphatic bifunctional alcohols, preferably linear C, to C,o dialcohols
such as
ethanediol, butanediol or hexanediol for example, most preferably butanediol,
and/or optionally from cycloaliphatic bifunctional alcohols, preferably those
comprising 5 or 6 C atoms in their cycloaliphatic ring such as
cyclohexanedimethanol for example, and/or, completely or in part instead of
diols, monomeric or oligomeric polyols based on ethylene glycol, propylene
glycol, tetrahydrofuran or copolymers thereof with molecular weights up to
1 ~ 4000, preferably up to 1000, and/or optionally small amounts of branched
bifunctional alcohols, preferably C3-C,, alkyl diols such as neopentyl glycol
for example, and optionally small amounts of alcohols of higher functionality
in addition, such as 1,2,3-propanetriol or trimethylolpropane for example, and
from aliphatic bifunctional acids, preferably C,-C,, alkyl dicarboxylic acids,
~0 such as, for example and preferably, succinic acid or adipic acid, and/or
optionally from aromatic bifunctional acids, such as terephthalic acid,
isophthalic acid or naphthalene dicarboxylic acid for example, and optionally
from small amounts of acids of higher functionality in addition, such as
trimellitic acid for example, or
B) from acid- and alcohol-functionalised components, preferably those
comprising 2 to 12 C atoms in their alkyl chain, for example hydroxybutyric
acid, hydroxyvaleric acid or lactic acid, or from derivatives thereof, for
example s-caprolactone or dilactide,
or from a mixture and/or a copolymer of A and B,
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wherein aromatic acids constitute a proportion of not more than ~0 % by weight
with
respect to all the acids;
aliphatic or partially aromatic polyester urethanes formed from
C) aliphatic bifunctional alcohols, preferably linear C, to C,o dialcohols
such as
ethanediol, butanediol or hexanediol for example, most preferably butanediol,
and/or optionally cycloaliphatic bifunctional alcohols, preferably those
comprising 5 or 6 C atoms in their cycloaliphatic ring,, such as
cyclohexanedimethanol for example, and/or, completely or in part instead of
diols, monomeric or oligomeric polyols based on ethylene glycol, propylene
glycol, tetrahydrofuran or copolymers thereof with molecular weights up to
4000, preferably up to 1000, and/or optionally small amounts of branched
1 ~ bifunctional alcohols, preferably C3-C,, alkyl diols such as neopentyl
glycol
for example, and optionally small amounts of alcohols of higher functionality
in addition, preferably C~-C,, alkyl polyols such as 1,2,3-propanetriol or tri-
methylolpropane for example, and from aliphatic bifunctional acids, preferably
C,-C,, alkyl dicarboxylic acids, such as, for example and preferably, succinic
?0 acid or adipic acid, and/or optionally from aromatic bifunctional acids,
such as
terephthalic acid, isophthalic acid or naphthalene dicarboxylic acid for
example, and optionally from small amounts of acids of higher functionality in
addition, such as trimellitic acid for example, or
D) from acid- and alcohol-functionalised components, preferably those
comprising 2 to 12 C atoms in their alkyl chain, for example hydroxybutyric
acid, hydroxyvaleric acid or lactic acid, or from derivatives thereof, for
example s-caprolactone or dilactide,
30 or from a mixture and/or a copolymer of A and B,
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wherein aromatic acids constitute a proportion of not more than 50 % by weight
with
respect to all the acids;
E) from the reaction product of C and/or D with aliphatic and/or
cycloaliphatic
bifunctional isocyanates and optionally with isocyanates of higher
functionality in addition, which preferably comprise 1 to 12 C atoms or 5 to 8
C atoms in the case of cycloaliphatic isocyanates, e.a. tetramethylene
diisocyanate, hexamethylene diisocyanate or isophorone diisocyanate,
optionally with linear and/or branched and/or cycloaliphatic bifunctional
alcohols -and/or alcohols of higher functionality in addition, preferably C3-
C,,
alkyl diols or polyols or those comprising 5 to 8 C atoms in the case of
cycloaliphatic alcohols, e.g. ethanediol. hexanediol, butanediol or
cvclohexane-dimethanol, and/or optionally with linear and/or branched and/or
cycloaliphatic bifunctional amines and/or amino alcohols and/or with linear
1$ and/or branched and/or cycloaliphatic amines and/or amino alcohols of
higher
functionality in addition, preferably those comprising 2 to 12 C atoms in
their
alkyl chain, e.g. ethylenediamine or aminoethanol, and/or optionally with
other modified amines or alcohols such as ethylenediaminoethane-sulphonic
acid for example, as the tree acid or as a salt,
wherein the ester fraction represented by C) and/or D) is at least 75 % by
weight with
respect to the sum of C), D) and E);
aliphatic or aliphatic-aromatic polyester carbonates formed from
F) aliphatic bifunctional alcohols, preferably linear Cz to C,o dialcohols
such as
ethanediol, butanediol or hexanediol for example, most preferably butanediol,
and/or optionally cycloaliphatic bifunctional alcohols, preferably those
comprising S to 8 C atoms in their cycloaliphatic ring, such as
cyclohexanedimethanol for example, and/or, completely or in part instead of
diols; monomeric or oligomeric polyols based on ethylene glycol, propylene
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glycol, tetrahydrofuran or copolymers thereof with molecular weights up to
4000, preferably up to 1000, and/or optionally small amounts of branched
bifunctional alcohols, preferably with C,-C,, alkyl dicarboxylic acids, such
as
neopentyl glycol ,for example. and optionally small amounts of alcohols of
higher functionality in addition, such as 1,2,3-propanetriol or tri-
methylolpropane for example, and from aliphatic bifunctional acids, preferably
C,-C,, alkyl dicarboxylic acids. such as, for example and preferably, succinic
acid or adipic acid, and/or optionally from aromatic bifunctional acids, such
as
terephthalic acid, isophthalic acid or naphthalene dicarboxylic acid for
example, and optionally from small amounts of acids of higher functionality in
addition, such as trimellitic acid for example, or
G) from acid- and alcohol-functionalised components, preferably those
comprising 2 to 12 C atoms in their alkyl chain, for example hydroxybutyric
acid, hydroxyvaleric acid or lactic acid, or from derivatives thereof, for
example s-caprolactone or dilactide,
or from a mixture and/or a copolymer of F and G,
wherein aromatic acids constitute a proportion of not more than 50 % by weight
with
respect to all the acids;
H) a carbonate fraction which is produced from aromatic bifunctional phenols,
preferably bisphenol A, and carbonate donors, for example phosgene,
or
a carbonate fraction which is produced from esters of aliphatic carbonic acids
or derivatives thereof, such as esters of chlorocarbonic acid for example, or
from esters of aliphatic carboxylic acids or derivatives thereof, such as
salts for
example, and carbonate donors, for example phosgene, wherein
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the ester fraction represented by F) and/or G) is at least 70 % by weight with
respect
to the sum of F), G) and H);
aliphatic or partially aromatic polyester amides formed ti-om
I) aliphatic bifunctional alcohols, preferably linear C, to C,~ dialcohols
such as
ethanediol, butanediol or hexanediol for example, most preferably butanediol,
and/or optionally cycloaliphatic bifunctional alcohols, preferably those
comprising 5 to 8 C atoms, such as cyclohexanedimethanol for example,
and/or, completely or in part instead of diols, monomeric or oligomeric
polvols based on ethylene glycol, propylene glycol, tetrahydrofuran or
copolymers thereof with molecular weights up to 4000, preferably up to 1000,
and/or optionally small amounts of branched bifunctional alcohols, preferably
1 ~ C~-C,, alkyl polyols such as neopentyl glycol for example, and optionally
small amounts of alcohols of higher functionality in addition, preferably C~-
C,,
alkyl polyols such as 1,2,3-propanetriol or trimethylolpropane for example,
and from aliphatic bifunctional acids, preferably C,-C,, alkyl dicarboxylic
acids. such as, for example and preferably, succinic acid or adipic acid,
and/or
~0 optionally from aromatic bifunctional acids, such as terephthalic acid,
isophthalic acid or naphthalene dicarboxylic acid for example, and optionally
from small amounts of acids of higher functionality in addition, such as
trimellitic acid for example, or
K) from acid- and alcohol-functionalised components, preferably those
comprising 2 to 12 C atoms in their alkyl chain. for example hydroxybutyric
acid. hydroxyvaleric acid or lactic acid, or from derivatives thereof, for
example ~-caprolactone or dilactide,
30 or from a mixture and/or a copolymer of I and K,
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wherein aromatic acids constitute a proportion of not more than ~0 % by weight
with
respect to all the acids;
L) an amide fraction formed from aliphatic and/or cycloaliphatic bifunctional
amines and/or optionally from small amounts of branched bifunctional amines,
preferably linear aliphatic C, to C,° diamines, and optionally ti-om
small
amounts of amines of higher functionality in addition, the preferred amines
being hexamethylenediamine or isophorone diamine, most preferably
hexamethylene-diamine, and from linear and/or cycloaliphatic bifunctional
acids, preferably those comprising 2 to 12 C atoms in their alkyl chain or
comprising a CS or C6 ring in the case of cycloaliphatic acids, and/or
optionally
from small amounts of branched bifunctional acids and/or optionally aromatic
bifunctional acids, such as terephthalic acid, isophthalic acid or naphthalene
dicarboxylic acid for example. and optionally from small amounts of acids of
1 ~ higher functionality in addition, preferably those comprising 2 to 10 C
atoms,
or
M) comprising an amide fraction formed from acid- and amine-functionalised
components, preferably those comprising 4 to 20 C atoms in their
?0 cycloaliphatic chain, preferably w-laurolactam or E-caprolactam, most
preferably s-caprolactam,
or comprising a mixture of L) and M) as an amide fraction, wherein
25 the ester fraction represented by I) and/or K) is at least 30 % by weight
with respect
to the sum of I), K), L) and M), wherein with the proportion by weight of
ester
structures preferably. ranges from 30 to 70 % by weight and the proportion of
amide
structures preferably ranges from 70 to 30 % by weight.
30 All the acids can also be used in the form of derivatives, such as acid
chlorides or esters
for example, said esters including both monomeric and oligomeric esters.
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The biodegradable polyester amides according to the invention can be
synthesised
either by the "polyamide method''. comprising the stoichiometric mixing of the
starting components, optionally with the addition of water, and subsequent
removal of
water from the reaction mixture, or by the "polyester method", comprising the
stoichiometric mixing of the starting components and the addition of an excess
of
diol, with esterification of the acid groups and subsequent
transesterification or
transamidisation of the ester. In the second case, the excess of diol is also
removed
again by distillation, in addition to the removal of water by distillation.
Synthesis is
preferably effected by the ''polyester method'' described above.
The condensation polymerisation process can also be speeded up by the use of
known
catalysts. It is possible to employ both the known phosphorus compounds which
speed up the synthesis of polyamides, and to employ acid or organometallic
catalysts
I ~ for the esterification process. It is also possible to use combinations of
both types of
catalysts to speed up the condensation polymerisation process.
It must be ensured that the catalysts do not have a negative effect either on
the
biodegradability or compostability or on the quality of the resulting compost.
The condensation polymerisation process to form polyester amides can also be
influenced by the use of lysine, lysine derivatives or other products which
promote
branching of amides, such as aminoethyl-aminoethanol (see DE 3831709 for
example).
The production of polyesters, polyester carbonates and polyester urethanes is
generally known or can be carried out analogously by known methods (see EP-A
304
787, WO 95/12629, WO 93/13154, EP-A 682 054, EP-A 593 975, for example).
The polyesters, polyester urethanes, polyester carbonates or polyester amides
according to the invention may also contain 0.1 to ~ % by weight, preferably
0.1 to 1
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by weight, of branching agents (see the description of the polymers also).
These
branching agents may be trifunctional alcohols, such as trimethyolpropane or
glycerol
for example. tetrafunctional alcohols such as pentaerythritol, or
trifunctional
carboxylic acids such as citric acid. Branching agents increase the melt
viscosity of
the polyester amides according to the invention to a value such that extrusion
blow-
moulding is possible with these polymers. The biodegradation of these
materials is not
impaired thereby.
The biodegradable/compostable polyester urethanes, polyesters, polyester
carbonates
and polyester amides generally have a molecular weight of at least 10,000
g/mol and
generally comprise a random distribution of the starting materials in the
polymer. In a
synthesis which is typical of polyurethanes, optionally from C) and D) as well
as from
E), a completely random distribution of the monomer components cannot always
be
anticipated.
Biodegradable polymers are commercially available, and are sold by Bayer AG
under
the product codes BAK 1095 and BAK 2195, for example.
Alcohols, ketones, ethers, halogenated or halogen-free hydrocarbons or
mixtures
thereof can be used as solvents. Examples thereof include ethanol, acetone,
ethyl
acetate, isopropanol, methanol, dichloromethane chloroform, tetrahydrofuran
and
toluene. Solvents which are environmentally compatible are preferably used.
Other environmentally compatible, water-miscible solvents include dimethyl
sulphoxide (DMSO) and N-methyl-2-pyrrolidinone. Solvents can also be used in
admixture with water, e.g. a mixture of ethanol and water. The solubility of
the
solvent in water can also be increased by the addition of alcohol. The alcohol
used
here can have different specifications. Possible examples include methanol,
ethanol,
(iso-, n-)propanol, (n-, iso-, tert.-)butanol, or ketones (acetone, 2-
butanone). It is
essential that the polymer is dissolved or dispersed in the solvent but is
insoluble in
water. A solution which has proved to be particularly suitable is a solvent
mixture
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containing a C,-C4 alcohol, a C,-CG ketone and/or an aromatic carboxylic acid
or a salt
thereof, particularly a solution which is prepared by the method described in
German
Patent Application 19 640 032.5, which has not been previously published and
to
which express reference is hereby made.
Customary binding agents can be used for binding the organic liquid. These
binding
agents can be sprayed or poured on to the surface of the water. just like the
solution.
Examples of binding agents such as these include powdered rubber, peat. cork
and/or
latices, which can be used individual or in combination.
The binding agent can be applied to the surface of the water before or after
the
solution is applied. Preferably, however, the solution is applied first, in
order to
delimit and fix a defined polluted surface area. which can then be treed from
the oil or
other organic liquid. This results in particular in a time advantage. due to
which
1 ~ further spreading of the organic liquid polluting the surface water can be
minimised.
