Note: Descriptions are shown in the official language in which they were submitted.
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Hydrogels based on polyisobutene succinic acid esters
Description
The present invention relates to the use of esters of polyisobutenesuccinic
acid for
producing hydrogels, and to the use of such hydrogels for cleaners and care
compositions for the home (so-called homecare products), for cosmetics, and
also for
medical products.
Hydrogels, i.e. water-comprising gels based on crosslinked, water-swellable
but
simultaneously water-insoluble polymers are of interest for a very wide
variety of
applications. Depending on the type of polymer, they are used as biomaterials
in the
pharmaceutical or medical sector, for example for contact lenses, wound
closure
materials, soft implants, for coating surfaces, for example biomedical
articles such as
implants or contact lenses, for producing biosensors (see Rompp Chemie-
Lexikon,
10th edition, Georg Thieme Verlag 1997, p. 1835 and literature cited therein).
Hydrogels laden with perfume or surfactants are sometimes used in fragrance
dispensers or as cleaners. Despite a large number of known synthetic and
natural
polymeric hydrogel formers such as poly(meth)acrylic acids, polyvinyl
alcohols,
polyvinylpyrrolidones, polyalkylene ethers, pectins, alginates and the like,
there is a
continuous need for new gel formers.
EP 1318191 discloses water-containing pastes for fragrance release for the
sanitary
sector which, besides water and perfume substances, comprise a block copolymer
which has oligo- or polyethylene oxide, oligo- or polypropylene oxide, or
oligo- or
polybutylene oxide groups. Specifically, polyoxyethylene-polyoxypropylene di-
and
triblock copolymers are specified. Pastes of this type adhere well to ceramic
surfaces
and are not rinsed off as a whole under the action of water, but dissolve
slowly and
completely only after or during frequently repeated action of water. It has
proven
disadvantageous that, in the event of relatively infrequent action of water
and/or in the
event of prolonged intervals between repeated actions of water, pastes of this
type
have a tendency to dry out and can then no longer be removed completely. These
dried-out pastes look unpleasant too. A further disadvantage of these pastes
is their
low dimensional stability, as a result of which they run down the ceramic wall
and form
unattractive "noses".
The object of the present invention is to provide new gel formers for
hydrogels. These
gel formers should form hydrogels which are dimensionally stable at least over
a
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prolonged period, and moreover have no or no significant surface-active
properties.
Furthermore, biocompatibility is desirable.
WO 02/02674 describes block copolymers, in particular triblock and higher
multiblock
copolymers, which are obtainable by reacting silane-terminated polyisobutene
with
allyl-terminated polyalkylene glycol ethers. The block copolymers are
swellable with
water. Their production is comparatively complex. The properties of the
hydrogels
produced therefrom, especially their mechanical properties, are
unsatisfactory.
DE 10125158 describes, inter alia, esters of polyisobutenesuccinic acid with
an alcohol
selected from poly-C2-C4-alkylene glycols and the use thereof as emulsifier
for water-
in-oil emulsions.
WO 2007/014915 describes aqueous polymer dispersions of polyolefins using
polyisobutenes functionalized with hydrophilic groups, such as, for example,
esters of
polyisobutenesuccinic acid with an alcohol selected from poly-C2-C4-alkylene
glycols,
as emulsifiers.
The use of such esters for producing hydrogels has hitherto not been
described.
Surprisingly, it has been found that esters of polyisobutenesuccinic acid with
an alcohol
selected from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-
C1-C22-
alkyl ethers form stable hydrogels with water, i.e. act as gel formers.
The invention therefore relates to the use of esters of polyisobutenesuccinic
acid with
an alcohol selected from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene
glycol
mono-C1-C22-alkyl ethers in hydrogels or as gel former for hydrogels, in
particular in
hydrogels which can be used in cleaners and care compositions for the home
(homecare products), in cosmetics, and also for medical products.
The invention also relates to hydrogels, in particular hydrogels for cleaners
and care
compositions for the home, for cosmetics, and also for medical products, where
the
hydrogels comprise, besides water, at least one ester of polyisobutenesuccinic
acid
with an alcohol selected from poly-C2-C4-alkylene glycols and poly-C2-C4-
alkylene
glycol mono-Ci-C22-alkyl ethers.
The invention also relates to the use of esters of this type for producing
hydrogels, and
to a process for producing the hydrogels, in which at least one ester of
polyisobutenesuccinic acid with an alcohol selected from poly-C2-C4-alkylene
glycols
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and poly-C2-C4-alkylene glycol mono-Ci-C22-alkyl ethers is incorporated into
an
aqueous liquid, or mixed with the aqueous liquid.
The hydrogels according to the invention are stable, i.e. they are
dimensionally stable
over a large temperature range from, for example, 0 to 90 C, in particular 0
to 70 C,
and do not have a tendency to separate even upon mechanical stress. The gel
formers
present therein, i.e. the esters of polyisobutenesuccinic acid described here,
moreover,
do not exhibit surface-active properties, i.e. at a concentration of 1 g/I,
they do not
lower the surface tension of the water below 45 mN/m, determined by the ring
method
in accordance with DIN 53914: 1980-03 at 25 C. On account of the gel formers
used,
the hydrogels are, moreover, biocompatible, i.e. they have no, or no
noteworthy,
disadvantageous effect on living beings or living material such as cell
material or
tissue.
The hydrogels according to the invention have good adhesion on polar surfaces,
in
particular inorganic surfaces such as glass or ceramic, and are not
immediately rinsed
off upon the action of water, but dissolve without leaving a residue, only
after prolonged
and frequently repeated action of water. Moreover, they can be formulated
without
disadvantages with fragrances or other substances which promote the cleaning
or
disinfection of sanitary ceramicware. In addition, these hydrogels only have a
slight
tendency to dry out. Furthermore, the hydrogels are dimensionally stable and
are
therefore suitable for producing molded articles, e.g. in fragrance
dispensers.
The hydrogels according to the invention can be easily formulated with
fragrances or
other additives for cleaners, such as, for example, surfactants, dyes,
preservatives,
disinfectants, complexing agents, thickeners, humectants, disintegrants, foam
stabilizers or substances which dissolve lime or urine scale, and are
especially suitable
for use in the sanitary sector. They adhere well to ceramic surfaces and are
not rinsed
off as a whole under the action of water, but dissolve slowly and completely
only after
frequently repeated action of water. In particular, it has proven advantageous
that, in
the event of infrequent action of water and/or in the case of prolonged
intervals
between the repeated actions of water, pastes of this type have no, or only a
low,
tendency to dry out and can be removed completely by repeated rinsing with
water
even in cases of relatively infrequent action of water.
A hydrogel former is understood as meaning a polymer which forms stable
hydrogels
with water upon the action of water and the associated swelling at least
within a certain
temperature range, e.g. in the range from 5 to 40 C. A stable hydrogel is
understood as
meaning a hydrogel which does not separate in a significant way upon
mechanical
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stress and/or prolonged storage, at least within a certain temperature range,
e.g. in the
range from 5 to 40 C, i.e. at which no significant deposition of an aqueous
serum takes
place under these conditions.
Without being bound to one theory, it is assumed that in the hydrogels
according to the
invention the ester of polyisobutenesuccinic acid binds the water to form a
3-dimensional, polymeric network, with the polyalkylene groups of the ester
presumably bringing about the binding of the water and the good adhesion to
the polar
surfaces, whereas the nonpolar polyisobutenyl radicals, on account of
hydrophobic
interactions and association, lead to a physical, i.e. non-covalent,
crosslinking of the
polymer chains and thus to the formation of a three-dimensional, dimensionally
stable
polymer network.
Polyisobutenesuccinic acid is understood as meaning oligomeric or polymeric
macromolecules with an oligomer radical or polymer radical, respectively,
which is
derived from isobutene and which has, on one of its termini 1 or 2, radicals
derived
from succinic acid, i.e. radicals of the formula SA
-CH(COOH)CH2COOH (SA)
and accordingly 2 or 4 carboxyl groups, and also mixtures thereof.
Polyisobutenesuccinic acids can therefore be described by the following
formulae I la
and Ilb:
PIB-CH(COOH)CH2COOH (11a)
P1B14CH(COOH)CH2COOH]2 (11b)
where PIB in formula Ila is a monovalent oligomer radical or polymer radical
derived
from polyisobutene, and PIB' in formula Ilb is a divalent oligomer radical or
polymer
radical derived from polyisobutene.
In the esters of polyisobutenesuccinic acid used according to the invention,
at least one
of the carboxyl groups is present in the form of the ester with a poly-C2-a4-
alkylene
glycol or a poly-C2-C4-alkylene glycol mono-Ci-C22-alkyl ether. Esters of this
type can
be described by the general formulae la and lb:
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,-Pag
0
PIB ________________________________________ (la)
0
Pag
C)
2KLO
(lb)
PIB'
,
0 0 R
R'
5 in which PIB and PIB' have the meanings given above for formulae Ila and
Ilb, R and
R', independently of one another, are hydrogen or Pag and Pag is a radical
derived
from a poly-C2-C4-alkylene glycol or a poly-C2-C4-alkylene glycol mono-Ci-C22-
alkyl
ether. In the formulae la and lb, R is in particular hydrogen.
Poly-C2-C4-alkylene glycols are understood as meaning linear or branched
oligomers
or polymers which are composed essentially of repeat units of the formula -A-0-
(hereinbelow also alkylene oxide repeat units), in which A is C2-C4-
alkanediyl, and
which have hydroxyl groups on their termini.
Poly-C2-C4-alkylene glycol mono-Ci-C22-alkyl ethers are understood as meaning
linear
or branched oligomers or polymers which are composed essentially of repeat
units of
the formula -A-0-, in which A is C2-C4-alkanediyl, which have, at one of their
ends, a
Cl-C22-alkyl group bonded via oxygen, and which have hydroxyl groups at the
other
terminus or the other termini.
In these poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-Ci-
C22-alkyl
ethers, the repeat units of the formula -A-0- may be identical or different.
If the poly-
C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-Ci-C22-alkyl ethers
have
different repeat units of the formula -A-0-, these may be arranged randomly,
alternately
or in a plurality, e.g. 2, 3 or 4, blocks. In one specific embodiment of the
invention, the
poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-C-1-C22-alkyl
ethers
have different repeat units of the formula -A-0- which are arranged randomly.
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In this context, C2-C4-alkanediy1 is a saturated divalent hydrocarbon radical
having 2 to
4 carbon atoms, such as 1,2-ethanediyl, 1,2-propanediyl, 1,3-propanediyl,
1,4-butanediyl, 1,2-butanediyl, 1,3-butanediyl, 2,3-butanediy1 or 1-methy1-1,2-
propanediyl.
In this context, Cl-C22-alkyl is a saturated, acyclic monovalent hydrocarbon
radical
having 1 to 22 carbon atoms, in particular having 1 to 8 carbon atoms or 1 to
4 carbon
atoms, such as methyl, ethyl, n-propyl, isopropyl, 1-butyl, 2-butyl, tert-
butyl, isobutyl,
n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl,
isooctyl, 2-ethylhexyl,
n-nonyl, isononyl, n-decyl, 2-propylheptyl, n-undecyl, n-dodecyl, n-tridecyl,
myristyl,
pentadecyl, palmityl (= cetyl), heptadecyl, octadecyl, nonadecyl, arachinyl or
behenyl.
Polymer radicals derived from isobutene, hereinbelow also polyisobutenyl
radicals, are
understood as meaning organic radicals which are derived from linear or
branched
oligomers or polymers of isobutene and which can comprise, polymerized
therein, up to
20% by weight, preferably not more then 10% by weight, of C2-C12-olefins
different from
isobutene, such as 1-butene, 2-butene, 2-methyl-1-butene, 2-methylpentene-1, 2-
methylhexene-1, 2-ethylpentene-1, 2-ethylhexene-1, 2-propylheptene-1. Radicals
of
this type can be described in the case of monovalent radicals PIB for example
by the
following formulae
- CH2 - CH3 - CH3
*
and in the case of divalent radicals PIB', for example by the following
formulae
/* /*
*
in which the value p+2 corresponds to the degree of polymerization and
indicates the
number of isobutene units in the polyisobutene radical and * signifies the
linkage to the
succinic acid (ester) radical. In these formulae, some of the isobutene units
-CH2C(CH3)2-, generally not more than 20% by weight, preferably not more than
10%
by weight, can be replaced by C2-Ci2-alkane-1,2-diylgroups derived from C2-C12-
olefins which are different therefrom. The degree of polymerization p+2 is
typically in
the range from 5 to100, in particular in the range from 8 to 80 and
specifically in the
range from 15 to 65.
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With regard to the use according to the invention in hydrogels, preference is
given to
those esters of polyisobutenesuccinic acid which, based on the total weight of
the
ester, consist to at least 50% by weight, in particular to at least 70% by
weight, of
esters of the formula la. Preferably, the esters of polyisobutenesuccinic acid
comprise,
based on the total weight of the ester, less than 30% by weight, in particular
less than
20% by weight, of esters of the formula lb.
As a consequence of the preparation, the esters of polyisobutenesuccinic acid
may
comprise unmodified polyisobutene. Unless stated otherwise, this is not
included in the
esters here and below. The fraction of polyisobutene can constitute up to 50%
by
weight, but preferably not more than 40% by weight or not more than 30% by
weight,
based on the total amount of ester + polyisobutene.
With regard to the use according to the invention in hydrogels, preference is
given to
those esters of polyisobutenesuccinic acid whose polyisobutene radical of the
ester
has a number-average molecular weight in the range from 500 to 5000 daltons,
in
particular in the range from 800 to 3600.
In a specific embodiment of the invention, polyisobutene radicals of the
polyisobutenesuccinic acid esters have a narrow molecular weight distribution.
The
polydispersity is then preferably at most 1.4, particularly preferably at most
1.3, in
particular at most 1.2. Polydispersity is understood as meaning the quotient
of weight-
average molecular weight Mw and number-average molecular weight Mn (PDI =
Mw/Mn).
With regard to the use according to the invention in hydrogels, preference is
given to
those esters of polyisobutenesuccinic acid which are esterified with an
alcohol selected
from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-Ci-C22-
alkyl
ethers, or a mixture of these alcohols, where the alcohol or the alcohols has
or have a
number-average molecular weight in the range from 500 to 15 000 daltons, in
particular
in the range from 800 to 10 000 daltons and specifically in the range from
1200 to 5000
daltons.
Furthermore, it has proven to be advantageous if the alcohol which is
esterified with the
polyisobutenesuccinic acid is unbranched, i.e. is selected from linear poly-C2-
C4-
alkylene glycols and linear poly-C2-C4-alkylene glycol mono-Ci-C20-alkyl
ethers.
Unbranched, i.e. linear poly-C2-C4-alkylene glycols and linear poly-C2-C4-
alkylene
glycol mono-Ci-C20-alkyl ethers can be described by the following formula
(III):
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HO¨FA-0¨FR' (III)
Here, A is C2-C4-alkanediy1 as defined above, which may be identical or
different and
which is preferably selected from 1,2-ethanediy1 and 1,2-propanediyl. R' is
hydrogen or
Cl-C22-alkyl, in particular hydrogen or Cl-Clo-alkyl and specifically hydrogen
or C1-C4-
alkyl, e.g. methyl. The variable n indicates the average number of repeat
units [A-01
(number-average) and is typically in the range from 10 to 350, in particular
in the range
from 15 to 200.
Accordingly, the radical Pag in the formulae la and lb is preferably a radical
of the
formula
(Pag)
in which A, R and n have the meanings given above and * signifies the linkage
to the
oxygen atom of the polyisobutenesuccinic acid radical.
In formula III or in the formula for Pag, the repeat units of the formula -A-0-
may be
identical or different. If the formulae III or in the formulae for Pag have
different repeat
units of the formula -A-0-, these may be arranged randomly or in a plurality,
e.g. 2, 3 or
4 blocks. In a specific embodiment of the invention, the formulae III and in
the formulae
for Pag have different repeat units of the formula -A-0-, which are arranged
randomly.
Furthermore, it has proven to be advantageous if the alcohol which is
esterified with the
polyisobutenesuccinic acid is composed, to at least 50 mol%, and in particular
to at
least 70 mol%, based on the total number of alkylene oxide repeat units in the
alcohol,
of repeat units of the formula [CH2CH20]. Accordingly, in the formulae III and
Pag, the
fraction of repeat units of the formula [CH2CH20] is at least 50 mol%, and in
particular
at least 70 mol%, based on the total number of repeat units A-0.
In a specific embodiment of the invention, all or virtually all of the repeat
units A-0 of
the poly-C2-C4-alkylene glycol or of the poly-C2-C4-alkylene glycol mono-Ci-
C20-alkyl
ether, or all or virtually all of the repeat units A-0 in the formulae III and
Pag, are repeat
units of the formula [CH2CH20].
In a further preferred embodiment of the invention, the alcohol which is
esterified with
the polyisobutenesuccinic acid, in particular the alcohol of the formula III
or the radical
Pag, comprises
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- 50 mol% to 99 mol%, and in particular 70 mol% to 98 mol%, based on the
total
number of alkylene oxide repeat units in the alcohol, of repeat units of the
formula [CH2CH20], and
- 0.1 mol% to 50 mol%, and in particular 2 mol% to 30 mol%, based on the
total
number of alkylene oxide repeat units in the alcohol, of repeat units of the
formula [A'-0], in which A' is C3-C4-alkanediyl, and in particular repeat
units of the
formula [CH2CH(CH3)0].
In one specific version of this preferred embodiment, the repeat units
[CH2CH20] and
[A'-0] which are different from one another are not arranged in a blocklike
manner, but
are in random distribution or arranged alternately.
In addition, it has proven to be advantageous if the alcohol constituent and
the
polyisobutenesuccinic acid on which the ester is based are selected such that
the ester
has, on average, a weight ratio of polyisobutene radical to alcohol radical in
the range
from 10:1 to 1:30, preferably in the range from 1.5:1 to 1:20 and in
particular in the
range from 1:1 to 1:10.
The preparation of the esters of polyisobutene succinic acid used according to
the
invention is possible in a manner known per se by reacting
polyisobutenesuccinic acid
or an ester-forming derivative of polyisobutenesuccinic acid with a poly-C2-C4-
alkylene
glycol or poly-C2-C4-alkylene glycol mono-Ci-C22-alkyl ether or mixtures
thereof under
esterification conditions. Processes for this are known in principle, e.g.
from
DE 10125158 and WO 2007/014915 cited at the start.
Suitable ester-forming derivatives of polyisobutenesuccinic acid are the acid
halides
and the Ci-C4-alkyl esters of polyisobutenesuccinic acid and also in
particular
polyisobutenesuccinic anhydride.
In one preferred embodiment of the invention, ester of polyisobutenesuccinic
acid is
used which is obtainable by reacting polyisobutenesuccinic anhydride with an
alcohol
selected from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-
C2-C20-
alkyl ethers, in particular an alcohol of the formula III, or a mixture of
these alcohols.
Polyisobutenesuccinic anhydride is understood here and below as meaning the
internal
anhydrides of polyisobutenesuccinic acid, i.e. substances in which the two
carboxyl
groups of the succinic acid radical form a 1-oxolane-2,5-dion-2-y1 radical.
Polyisobutenesuccinic anhydrides of this type can be described in particular
by the
following formulae
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PIB
0
0 (IVa) (IVb)
0 ON
0'O
in which PIB and PIB' have the meanings given above for formulae la, lb, I la
and Ilb.
5 Preferably, the polyisobutenesuccinic anhydride used for producing the
ester
comprises, based on the total weight of the anhydride, to at least 50% by
weight, in
particular to at least 70% by weight, the anhydride of formula IVa.
Preferably, the
polyisobutenesuccinic anhydride used for producing the ester comprises, based
on the
total weight of the anhydride, less than 30% by weight, in particular less
than 20% by
10 weight, of anhydride of the formula IVb. As a consequence of the
preparation, the
polyisobutenesuccinic anhydride can comprise polyisobutene. The fraction of
the
polyisobutene can constitute up to 50% by weight, but preferably not more than
40% by
weight or not more than 30% by weight, based on the total amount of
polyisobutenesuccinic anhydride + polyisobutene.
The relative fraction of compounds of the formula IVa and IVb in the
polyisobutenesuccinic anhydride used to produce the ester corresponds to the
saponification number of the polyisobutenesuccinic anhydride, determined
analogously
to DIN 53401. For the properties of the ester, it has proven to be
advantageous if the
polyisobutenesuccinic anhydride has a saponification number SN in the range
from 40
to 140 mg KOH/g and in particular in the range from 70 to 100 mg KOH/g,
determined
in accordance with DIN 53401.
The polyisobutenesuccinic anhydrides used for the reaction are known, e.g.
from DE
2702604 A1, US 5883196, US 5420207 and EP 629638, and also the publication by
M. Tessier et al., Eur. Polym. J, 20, 1984, p. 269-280 and H. Mach et al.,
Lubrication
Science 12-2, 1999, p. 175-185.
Preference is given to polyisobutenesuccinic anhydrides which are obtainable
by
reacting olefinically unsaturated polyisobutenes with maleic anhydride.
Particular
preference is given to products which are obtained by reacting highly reactive
polyisobutenes with maleic anhydride. Highly reactive polyisobutenes are
understood
as meaning polyisobutenes with at least 50 mol%, often with at least 60 mol%
and in
particular with at least 80 mol%, based on the total number of polyisobutene
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macromolecules, of terminally arranged double bonds. The terminally arranged
double
bonds may either be vinyl double bonds [-CH=C(CH3)2] (13-olefin) or vinylidene
double
bonds [-CH-C(=CH2)-CH3] (a-olefin). Preferred highly reactive polyisobutenes
have
predominantly vinylidene double bonds. Highly reactive polyisobutenes are
commercially available, e.g. the Glissopal grades from BASF SE, thus e.g.
Glissopal
1000 and Glissopal 1300, Glissopal 2300.
The poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-C2-C20-
alkyl
ethers used for the reaction are likewise known from the prior art and
commercially
available, for example under the trade names Pluriol , e.g. the Pluriol E
grades such
as Pluriol E 600, Pluriol E 600 S, Pluriol E 1000, Pluriol E 1000 S,
Pluriol E
1500, Pluriol E 3400, Pluriol E 6000, Pluriol E 8000, Pluriol E 9000, the
Pluriol
P grades such as Pluriol E 600, Pluriol E 900, Pluriol E 2000, Pluriol E
4000, the
Pluriol A grades such as Pluriol A 1020 E, Pluriol A 2000 E, Pluriol A
3010 E,
Pluriol A 5010 E, Pluriol A 1020 PE, Pluronic , e.g. the Pluronic PE grades
such
as Pluronic PE 3100, Pluronic PE 3500, Pluronic PE 4300, Pluronic PE 6100,
Pluronic PE 6120, Pluronic PE 6200, Pluronic PE 6400, Pluronic PE 6800,
Pluronic PE 7400, Pluronic PE 8100, Pluronic PE 9200, Pluronic PE 9400,
Pluronic PE 10100, Pluronic PE 10300, Pluronic PE 10400 and Pluronic PE
10500, or can be prepared analogously to standard processes by base-catalyzed
homo- or copolymerization of C2-C4-alkylene oxides such as ethylene oxide,
propylene
oxide, 1,2-butylene oxide, 2-methyl-1,2-propylene oxide (= isobutylene oxide).
The reaction of the polyisobutenesuccinic anhydride with the alcohol selected
from
poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-C2-C20-alkyl
ethers
can take place in a manner known per se analogously to the procedures
described in
DE 10125158 and WO 2007/014915.
For this, as a rule, the polyisobutenesuccinic anhydride is reacted with the
alcohol
selected from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-
C2-C20-
alkyl ethers in a molar ratio of 2:1 to 1:2, in particular 1.5:1 to 1:1.5 and
specifically
1.05:1 to 1:1.2, in each case based on the anhydride groups in the
polyisobutenesuccinic anhydride.
The reaction can be carried out in solution or without dilution. Examples of
suitable
solvents are aromatic hydrocarbons, e.g. benzene, toluene, xylenes,
mesitylene,
naphthalene, tert-butylbenzene, and mixtures thereof, (cyclo)aliphatic
hydrocarbons,
e.g. hexane, heptane, octane, isooctane, cyclohexane, cycloheptane,
cyclooctane,
tetralin, and mixtures thereof, halogenated hydrocarbons such as
dichloromethane,
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1,1-dichloroethane, 1,2-dichloroethane, 1,1-dichloroethene, 1,2-
dichloroethene,
chlorobenzene, dichlorobenzene, chlorotoluene and mixtures thereof, and also
mixtures of the aforementioned aromatic and (cyclo)aliphatic hydrocarbons and
mixtures of the aforementioned hydrocarbons with halogenated hydrocarbons.
The reaction can take place in the presence of a catalyst or in the absence of
catalysts.
As a rule, the reaction takes place at temperatures in the range from 60 to
250 C, often
in the range from 80 to 200 C and in particular in the range from 100 to 180
C.
Suitable catalysts are in particular basic compounds such as alkali metal and
alkaline
earth metal oxides, hydroxides, carbonates and hydrogencarbonates, and also
tertiary
organic amines, e.g. trialkylamines such as triethylamine, tripropylamine,
methyldiisopropylamine, tributylamine, dimethyl-tert-butylamine, and also
cyclic
alkylamines such as N-methylmorpholine, N-methylpiperidine, N-
methylpyrrolidine, and
triethylenediamine. If required, the catalyst is used in amounts of from 0.1
to 20 mol%,
based on the anhydride groups in the polyisobutenesuccinic anhydride.
As already mentioned in the introduction, the esters of polyisobutenesuccinic
acid with
an alcohol selected from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene
glycol
mono-Ci-C22-alkyl ethers form stable hydrogels with water, i.e. they can be
used as gel
formers.
Accordingly, the present invention also relates to hydrogels which, besides
water
(hereinbelow also component B), comprise at least one ester of
polyisobutenesuccinic
acid with an alcohol selected from poly-C2-C4-alkylene glycols and poly-C2-C4-
alkylene
glycol mono-Ci-C22-alkyl ethers, as described above in an amount sufficient to
form a
hydrogel.
The amount of component A required to form the hydrogel naturally depends on
the
other constituents of the hydrogel and on the precise constitution of
component A and
can be ascertained easily by the person skilled in the art through routine
experiments.
As a rule, irrespective of the other additives, a stable hydrogel is obtained
if the weight
ratio of component A to component B, i.e. water, is in the range from 4:1 to
1:6, often in
the range from 3:1 to 1:4 and in particular in the range from 2:1 to 1:3.
In the hydrogels according to the invention, the component A generally
constitutes 15
to 80% by weight, often 20 to 75% by weight, and in particular 25 to 65% by
weight,
based on the total weight of the hydrogel.
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13
In the hydrogels according to the invention, the total amount of components A
and B is
generally at least 70% by weight and in particular at least 80% by weight, of
the
hydrogel.
Typically, the hydrogel according to the invention comprises
a. 15 to 80% by weight, often 20 to 75% by weight, and in particular 25 to
65% by
weight, based on the total weight of the hydrogel, of component A and
b. 20 to 85% by weight, often 25 to 80% by weight, and in particular 35 to
75% by
weight, based on the total weight of the hydrogel, of water as component B.
Besides the aforementioned components, the hydrogel according to the invention
can
comprise one or more further constituents different from the components A and
B and
which are directed to the desired intended use. These constituents are also
referred to
below as component C.
Examples of component C are fragrances and customary additives present in
cleaners,
such as, for example, surfactants, dyes, preservatives, disinfectants,
complexing
agents, thickeners, humectants, disintegrants, foam stabilizers and substances
which
dissolve lime or urine scale, and mixtures of the aforementioned substances.
Accordingly, one embodiment of the invention relates to a hydrogel which
comprises,
besides component A and water (component B), at least one further constituent
as
component C, which is preferably selected from fragrances, surfactants, dyes,
preservatives, disinfectants, complexing agents, thickeners, humectants,
disintegrants,
foam stabilizers and substances which dissolve lime or urine scale, and
mixtures
thereof.
The fraction of component C will generally not exceed 30% by weight, often 25%
by
weight and in particular 20% by weight, based on the total weight of the
hydrogel, and
is, if desired, typically in the range from 0.1 to 30% by weight and in
particular in the
range from 1 to 20% by weight.
The nature of component C is governed in a manner known per se by the desired
intended use.
Accordingly, one embodiment of the invention relates to a hydrogel comprising:
a. 15 to 79.9% by weight, in particular 20 to 74.5% by weight, and
specifically 25 to
64% by weight, based on the total weight of the hydrogel, of component A,
,
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b. 20 to 84.9% by weight, in particular 25 to 79.5% by weight, and
specifically 35 to
74% by weight, based on the total weight of the hydrogel, of water as
component B,
c. 0.1 to 30% by weight, in particular 0.5 to 25% by weight, and
specifically 1 to
20% by weight, based on the total weight of the hydrogel, of at least one
further
constituent different from components A and B, which is also referred to below
as
component C,
where the total amount of components A, 6 and C is 100% by weight.
In one preferred embodiment of the invention, the hydrogel comprises at least
one
fragrance. Suitable fragrances which may be present in the hydrogels according
to the
invention comprise synthetic fragrances, semisynthetic fragrance mixtures and
natural
fragrance oils. Examples of synthetic fragrances are the synthetic products of
the ester,
ether, aldehyde, ketone, alcohol and hydrocarbon types. The natural fragrances
include in particular those perfume oils which are accessible from plant
sources.
Preference is given to using mixtures of different fragrances which together
produce a
pleasant scent note.
In one preferred embodiment of the invention, the hydrogel according to the
invention
comprises at least one surfactant. Suitable surfactants are typically selected
from
anionic, nonionic, amphoteric and cationic surfactants, and also mixtures
thereof. If
desired, the hydrogels according to the invention comprise surfactants
preferably in
amounts of from 0.01 to 30% by weight, based on the total weight of the
hydrogel.
The hydrogels according to the invention can furthermore comprise one or more
antimicrobial active ingredients, which can generally also act as
preservative.
The hydrogels according to the invention can further comprise substances which
dissolve lime or urine scale. These include in particular water-soluble
builders and
mixtures thereof with acids.
The hydrogels according to the invention can also comprise one or more
conventional
thickeners. Of suitability for this are in principle all viscosity regulators
used in the prior
art in detergents and cleaners. In one preferred embodiment of the invention,
the
hydrogel comprises no conventional thickener.
The hydrogels according to the invention are also largely dimensionally stable
even
under relatively large shear stresses, i.e. their deformability at 30 C and a
shear stress
of 102 Pa is typically less than 5% and in particular less than 1%, determined
at 30 C
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using a shear-stress-controlled rotary viscometer with cone/plate geometry and
a shear
stress range from 102 to 104 Pa. The yield point as a limit of the elastic
deformation
range is 30 C as a rule at a shear stress of at least 103 Pa, e.g. in the
range from 103 to
106 Pa.
5
The hydrogels according to the invention typically have a viscosity in the
range from
105 to 1010 Pas, often in the range from 105 to 108 Pas, determined at 30 C
using a
shear-stress-controlled rotary viscometer with cone/plate geometry in the
shear stress
range from 102 to 104 Pa.
The hydrogels according to the invention have good adhesion on polar surfaces,
in
particular inorganic surfaces such as glass or ceramic, and are not
immediately rinsed
off upon action of water, but dissolve, without leaving a residue, only after
prolonged
and frequently repeated action of water. Moreover, they can be formulated
without
disadvantages with fragrances or other substances which promote the cleaning
or
disinfection of sanitary ceramicware. The invention therefore also relates to
the use of
a hydrogel as described here for homecare products, in particular for
producing
compositions which release fragrance, e.g. fragrance-releasing pastes or for
producing
cleaning and care compositions for the sanitary sector, specifically for
pastes for
application in WCs and bidets, as described in WO 99/66021, WO 02/26925 or
EP 1318191.
The hydrogels according to the invention can be prepared in a simple manner by
incorporating at least one ester of polyisobutenesuccinic acid with an alcohol
selected
from poly-C2-C4-alkylene glycols and poly-C2-C4-alkylene glycol mono-C2-C20-
alkyl
ethers, as described here, optionally with some or all of the constituents of
component
C into an aqueous liquid which, if desired, besides water, can already
comprise some
or the total amount of the constituents of component C.
The incorporation can take place by simply mixing water or an aqueous liquid
which,
besides water, comprises some or the total amount of the constituents of the
optionally
desired component C. However, it is also possible to incorporate a solution of
component A, which optionally comprises some or all of the constituents of the
optionally desired component C, into water or an aqueous liquid, and then to
remove
the solvent.
The incorporation of component A and optionally further constituents into
water or the
aqueous liquid will generally take place at temperatures in the range from 10
to 100 C.
The use of mixing devices may be advantageous, but is generally not required.
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16
The figures and examples below serve to illustrate the invention in more
detail.
Figure 1: Viscosity of the polyisobutenesuccinic acid ester from preparation
example 11
as a function of the shear rate at 70 C (grey) and 90 C (black). Measuring
instrument:
stamping capillary viscometer.
Figure 2: Temperature sweep of the polyisobutenesuccinic acid esters from
preparation
examples 11 (grey) and 12 (black) at temperatures of 60 to 90 C where f= 1 Hz
and
def. = 0.1%, measuring instrument: shear-stress-controlled rotary rheometer.
Figure 3: Viscosities of the polyisobutenesuccinic acid esters from
preparation
example 11 as a function of shear stress, measuring instrument: shear-stress-
controlled rotary viscometer.
Figure 4: Viscosities of the hydrogel from example 21 as a function of shear
stress;
measuring instrument: shear-stress-controlled rotary viscometer.
Figure 5: Deformation of the polyisobutenesuccinic acid ester from preparation
example 11 as a function of shear stress, measuring instrument: shear-stress-
controlled rotary viscometer.
Figure 6: Deformation of the hydrogel from example 21 as a function of shear
stress,
measuring instrument: shear-stress-controlled rotary viscometer.
Abbreviations:
EO: ethylene oxide
PO: propylene oxide
PIBSA: polyisobutenesuccinic anhydride
Mn: number-average molecular weight
M: weight-average molecular weight
SN: saponification number
AN: acid number
OHN: OH number
ST: surface tension
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17
11 Analytics:
The saponification number SN was determined analogously to
DIN 53401:1998-06
The acid number AN was determined by titration of the polyisobutenesuccinic
acid ester in a mixture of toluene and ethanol. The AN indicates the number of
mg of potassium hydroxide which was used up to neutralize 1 g of the sample.
The OH number was determined analogously to DIN 53401:1971-12
The viscosity of the polyisobutenesuccinic acid esters was investigated by
means
of a shear-stress-controlled rotary rheometer (MCR300, plate/plate geometry,
25 mm, h = 1 mm) at temperatures of 60 to 90 C, and also by means of a
stamping capillary viscometer (Rosand, KVM geometry, annular capillary:
L/R = 294.70, L = 150.00 mm, R = 0.509 mm) at temperatures of 70 and 90 C.
The deformability and the yield point of the polyisobutenesuccinic acid ester
and
the resulting hydrogel produced therefrom were determined by means of a shear-
stress-controlled rotary viscometer (Physika MCR, plate/plate geometry, upper
plate d = 25 mm, distance: 2 mm) at a temperature of 30 C.
The surface tension ST was measured according to the ring method analogously
to DIN 53914: 1980-03. The ST is defined as the force in the surface per unit
of
length and has the dimension mN/m (10-3 newtons/meter).
The maximum water absorption capacity of sample 11 was tested both with
deionized water (demin. water) and also with non-deionized water (Jayco
solution) both at room temperature and also at 4 C.
For this, ca. 3 g of sample were placed in a Petri dish and melted at 80 C in
a
heating oven. After the sample had cooled back to room temperature, either
demin. water or Jayco solution was added, a ratio of sample to water of 1:9
being
established. The swelling behavior of sample 11 was then determined
gravimetrically.
The Jayco solution comprised the following salt concentrations: 2 g/I
potassium
chloride, 2 g/I sodium sulfate, 0.85 g/I ammonium dihydrogenphosphate, 0.15
g/I
,
PF 71467 CA 02822487 2013-06-20
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18
diammonium hydrogenphosphate, 0.5 g/I magnesium chloride hexahydrate,
0.25 g/I calcium chloride dihydrate.
III Feed materials:
Polyisobutenesuccinic anhydride 1: PIBSA with a saponification number SN of
87.5 mg KOH/g, prepared by reacting polyisobutene (Mn = 1000 g/mol) with
maleic anhydride (PIBSA 1000)
Polyisobutenesuccinic anhydride 2: PIBSA with a saponification number SN of
44 mg KOH/g, prepared by reacting polyisobutene (Mn = 2300 g/mol) with maleic
anhydride (PIBSA 2300)
Polyisobutenesuccinic anhydride 3: PIBSA with a saponification number SN of
84 mg KOH/g, prepared by reacting polyisobutene (Mn = 1000 g/mol) with maleic
anhydride
Polyisobutenesuccinic anhydride 4: PIBSA with a saponification number SN of
105 mg KOH/g, prepared by reacting polyisobutene (Mn = 1000 g/mol) with
maleic anhydride
Polyisobutenesuccinic anhydride 5: PIBSA with a saponification number SN of
145 mg KOH/g, prepared by reacting polyisobutene (Mn = 550 g/mol) with maleic
anhydride (PIBSA 550)
Polyether 1: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(ED/PO ratio 10, Mr, = 2587 g/mol; SN = 21.6 mg KOH/g)
Preparation of polyether 1: 69.7 g of diethylene glycol monomethyl ether and
3.1 g of an aqueous 50% strength by weight potassium hydroxide solution were
introduced as initial charge in an autoclave. The mixture was heated to 80 C
and
a vacuum of 10 mbar was applied for 2 h in order to remove the water. The
system was then rendered inert with nitrogen and the reaction mixture was
heated to 130 C. At this temperature, a mixture of 1277.8 g of ethylene oxide
(E0) and 168.4 g of propylene oxide (PO) was injected over the course of 5 h
and the mixture was after-stirred for 2 h at 130 C. The volatile constituents
were
then removed from the reaction mixture in vacuo, giving 1570 g of a white
solid,
which consisted essentially of KOH and the random EO/PO copolymer.
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Polyether 2: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(E0/P0 ratio 20:3; Mn = 1175 g/mol) prepared analogously to the preparation of
polyether 1.
Polyether 3: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(E0/P0 ratio 50:3; Mn = 2497 g/mol; SN = 22.7 mg KOH/g), prepared
analogously to the preparation of polyether 1.
Polyether 4: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(EXPO ratio 75:7.5; Mn = 3860 g/mol; SN = 16.8 mg KOH/g), prepared
analogously to the preparation of polyether 1.
Polyether 5: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(E0/P0 ratio 10; Mn = 5106 g/mol; SN = 13.2 mg KOH/g), prepared analogously
to the preparation of polyether 1.
Polyether 6: random poly(ethylene glycol-co-propylene glycol) monomethyl ether
(E0/P0 ratio 52:3; Mn = 2623 g/mol; SN = 23.9 mg KOH/g), prepared
analogously to the preparation of polyether 1.
Polyether 7: polyethylene glycol, Mn = 1500 g/mol
Polyether 8: polyethylene glycol, M,, = 6000 g/mol
Polyether 9: polyethylene glycol monomethyl ether, Mn = 2000 g/mol
Polyether 10: polyethylene glycol monomethyl ether, Mn = 3010 g/mol
Polyether 11: polyethylene glycol monomethyl ether, Mn = 5010 g/mol
Polyether 12: polyethylene glycol monomethyl ether, Mn = 1020 g/mol
Polyether 13: poly(ethylene glycol-co-propylene glycol) monomethyl ether,
= 1020 g/mol, molar ratio EO/PO 1:1
Polyether 14: polyethylene glycol, Mn = 600 g/mol
Polyether 15: polyethylene glycol, Mn = 1000 g/mol
,
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.
Surfactant: nonionic surfactant
IV Preparation examples
5 Preparation example 1: polyisobutenesuccinic acid ester
Polyisobutenesuccinic anhydride 2 (0.0506 mol; 129 g) was reacted with
polyether 7 (0.0506 mol; 75.9 g) at a temperature of 140 C without dilution.
The
reaction time was 3 hours. The acid number of the copolymer obtained was
12.6 mg KOH/g.
Preparation examples 2 to 16:
The polyisobutenesuccinic acid esters of preparation examples 2 to 16 were
prepared in a manner analogous to preparation example 1. The feed materials,
relative use amounts and the properties are summarized in table 1 below.
Table 1:
Preparation PIBSA Polyether PIBSA:polyether AN ST
example No. No. No. [mol:mol] [mg KOH/g] [mN/m]
1 2 7 1:1 12.6
2 1 8 1:1 7.9
3 1 9 1:1 17.8 50.2
4 1 10 1:1 12.5 54.6
5 1 11 1:1 3.6
6 1 12 1:1 8.8
7 1 13 1:1
8 1 14 1:1
9 1 2 1:1
10 1 15 1:1
11 1 1 1:1 13.5 49.3
12 1 5 1:1
13 1 1 1:0.9 12.8
141/ 1 1 1:0.9 16.9
15 1 4 1:0.9 46.9
16 1 9+10 1:1 52.9
1) reaction not quite complete
Investigation of the viscoelastic behavior of the polyisobutenesuccinic acid
ester from
preparation example 11 revealed, at shear rates in the range from 10-3 to 102
s-1 and in
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21
particular in the range from 10-3 to 101 s-1 in a temperature range from 60 to
90 C,
Newtonian viscoelastic behavior and viscosities in the range from 0 to 103 Pas
and in
particular viscosities from 6 to 400 Pas. Above a shear rate above 102s-1, the
viscosity
decreases linearly to below 2 Pas. (see figure 1).
Investigation of the viscoelastic behavior of the polyisobutene succinic acid
esters from
preparation examples 11 and 12 revealed that the temperature profile of the
viscosity
depends on the molecular weight of the alcohol selected from the poly-C2-C4-
alkylene
glycols and poly-C2-C4-alkylene glycol mono-C2-C20-alkyl ethers. The ester
from
preparation example 12 (black) reveals a greater temperature dependency than
the
ester from preparation example 11 (grey) (see figure 2).
The maximum water absorption capacity of the polyisobutenesuccinic acid ester
from
preparation example 11 is shown in table 2 below:
Table 2:
Water absorption capacity of preparation example 11
Solvent Demin. water Jayco solution
temperature [ C] 22 4 22 4
Water absorption
[% by wt.] 2) 81 110 130 103
2) Average value, based on the starting weight of the copolymer used.
V Hydrogels:
General preparation procedure.
The polyisobutenesuccinic acid ester was melted at a temperature of 70 C and
diluted with the amount of warm water and optionally surfactant given in table
3.
In all cases, a clear hydrogel was formed.
Example 1:
The gel of example 21 was prepared analogously to the general preparation
procedure from the polyisobutenesuccinic acid ester of preparation example 11
by dilution with water/surfactant. The hydrogel was then analyzed
viscometrically.
The results for example 21 are shown in figures 4 and 6.
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,
22
Table 3:
Polyisobutene-
Water Surfactant AN
Example succinic acid
[% by wt.] 4) ro by wt.] 4)
[mg KOH/g]
ester 3)
1 2 80 0 7.5
2 3 60 0 9.5
3 4 66.6 0 5.0
4 5 66.6 0 3.6
6 66.6 0 8.8
6 7 40 0
7 7 50 0
8 7 60 0
9 7 70 0
8 40 0
11 8 50 0
12 8 60 0
13 8 70 0
14 8 14 6
8 24 6
16 8 34 6
17 8 44 6
18 10 36 0
19 10 34 6
11 14 6
21 11 44 6
22 11 54 6
23 12 44 6
24 13 50 0
6 30 105)
3) preparation example number
4) based on the hydrogel
5) mixture of 9 parts by weight of the nonionic surfactant with 1 part by
weight of a
5 customary perfume oil
