Absorbing polymer

Absorbing polymer consisting of a polymer A which is an optionally modified polyvinyl alcohol or an optionally modified polysaccharide or a mixture of these, and of a polymer B which is a maleic anhydride homo- or copolymer having a hydrolysis time of 5 to 120 minutes, the anhydride groups being open and 0.005 to 5 mol % of the acid functions being esterified with hydroxyl groups of polymer A, and the remaining acid functions being present as free acid groups, as salts or as acid amide groups, an absorbing product containing this polymer and a process for their preparation.

The invention relates to a novel, absorbing polymer and to an absorbing 
product containing the former, to a process for their preparation and to 
their use for taking up and retaining water or aqueous solutions. 
Absorbing polymers usually consist of polymers or copolymers which are 
hydrophilic and which have been rendered water-insoluble by reaction with 
suitable crosslinking agents. Such materials can absorb and hold liquids 
or steam, so that they are most widely used in a wide range of fields, but 
in particular in the sanitary sector. In connection with a support, they 
are employed in all situations where liquids are to be removed rapidly, 
that is to say, for example, in tissue papers, nappies, tampons, bandages 
etc. On the other hand, such polymers can also be used with good success 
for retaining and later releasing moisture in the agricultural sector, but 
also in many other areas. There has therefore been no lack of attempts to 
provide such polymers. 
For example, in DE-A-2,923,435 there is disclosed a process for the 
preparation of a crosslinked polyvinyl alcohol (PVAL), in US-A-3,936,441 a 
process for the preparation of crosslinked cellulose in GB-A-2027714 a 
process for the preparation of crosslinked carboxyalkyl cellulose and in 
GB-A-1,508,123 a process for the preparation of crosslinked starch having 
absorbing properties. Besides the fact that these crosslinked hydrophilic 
polymers often contain a high proportion of water-soluble products, the 
crosslinking agents employed are poisonous monomers containing epoxy, 
halogen or acrylic groups Since the crosslinked, polymeric materials 
always contain a certain amount of still unreacted, monomeric crosslinking 
agents, their use in particular in the sanitary sector can cause effects 
which are injurious to health. 
US-A-4,332,917 describes the preparation of a ester in an organic solvent. 
For this purpose, the maleic anhydride groups are at least partially 
hydrolized, the two polymers are mixed in an organic solvent, and the 
solvent is evaporated. In EP-A-0,210,754 there is described a composition 
of polyalkylene oxides with copolymers which consist of units of an 
alpha-beta unsaturated monomer and a monomer which is copolymerizable with 
the former, for the preparation of a water-absorbing composition. However, 
in both cases the specific polymers are only held together via hydrogen 
bonds. 
From GB-A-1392624 it is known to crosslink polyethylene oxide with 
water-soluble polymers with the aid of ionizing radiation. However, plants 
which make possible the irradiation of substrates with ionizing radiation 
require complicated equipment and extensive protective measures. 
Unexpectedly, it was possible with the aid of the present invention to 
prepare an absorbing polymer which overcomes the disadvantages associated 
with the abovementioned polymers and their preparation. 
Accordingly, the invention relates to an absorbing polymer consisting of a 
polymer A and a polymer B, comprising polymer A being present in an amount 
of 10 to 99 percent by weight and being an optionally modified polyvinyl 
alcohol or an optionally modified polysaccharide or a mixture of these, 
and polymer B being present in an amount of 1 to 90 percent by weight and 
being a maleic anhydride homo- or copolymer having a hydrolysis time of 5 
to 120 minutes, the anhydride groups being opened and 0.005 to 5 % of the 
acid functions being esterified with the hydroxyl groups of polymer A and 
the remaining acid functions being present as free acid groups, as salts 
or as acid amide groups. 
Polymer A is an optionally modified polyvinyl alcohol (PVAL) or an 
optionally modified polysaccharide or a mixture of such polymers. PVAL is 
taken to mean conventional polyvinyl alcohols having molecular weights of 
about 10000 to 100000. Modified PVAL means that some of the hydroxyl 
groups of the PVAL are present in an esterified or etherified form. 
Esterified PVAL is understood as meaning either partially hydrolyzed 
polyvinyl acetate or completely or partially hydrolyzed polyvinyl acetate 
which is re-esterified. Compounds which are suitable for esterifying PVAL 
are, for example, reactive derivatives of di- or tricarboxylic acids, such 
as, for example, acid anhydrides of succinic acid, maleic acid, fumaric 
acid, itaconic acid or pyromellitic acid. The degree of substitution DS 
after the esterification is 0.005 to 0.5, preferably 0.01 to 0.3. Such 
products are commercially available or they can be prepared by a 
conventional esterification method, for example with the aid of a reactive 
carboxylic acid derivative, if appropriate in a diluent, using basic or 
acid catalysts. Compounds which are suitable for etherification are 
aliphatic or araliphatic sulphonic acids, phosphonic acids, carboxylic 
acids or their salts, and also quaternary ammonium salts having an 
aliphatic side chain, and in which this side chain carries a reactive 
leaving group or epoxy group and can, if appropriate, also be substituted 
by hydroxyl groups. Examples of such compounds are Na 
3-chloro-2-hydroxypropanesulphonate, chloromethylsulphonic acid, Na 
chloromethylphosphonate, Na monochloroacetate or glycidyltrimethylammonium 
chloride The degree of substitution DS after etherification is 0.005 to 
0.5, preferably 0.01 to 0.3. Such products are commercially available or 
they can be prepared under conventional etherification conditions, in 
which process the reactive leaving group of the compound employed for 
etherification and the hydrogen ion from the hydroxyl group of the PVAL 
are eliminated, if appropriate in a solvent in the presence of a base, 
this resulting in the formation of an ether bond. In the event that an 
epoxy group is present in the place of a reactive leaving group, 
etherification takes place with basic catalysis, in which case, after the 
etherification reaction, a hydroxyl group is additionally present in the 
alpha-position relative to the ether oxygen in the aliphatic side chain of 
the compound used for etherification. Substances which are used for 
esterification or etherification are known substances of organic 
chemistry. Preferred as the polymer A is a modified PVAL, for example a 
PVAL modified by esterification with succinic anhydride. 
Possible examples of polysaccharides are starch, dextran, xanthan, 
water-soluble cellulose derivatives, such as, for example, cellulose 
ethers, such as hydroxyalkylcellulose, methylcellulose, 
carboxylmethylcellulose and hydroxypropylcellulose or sodium alginate, 
guar and similar substances. Modified polysaccharides are polysaccharides 
in which some of the hydroxyl groups are esterified or etherified with 
compounds as have been described above in the case of PVALs. Modified 
polysaccharides are known and commercially available, or they can be 
prepared as described above in the case of the modified PVALs. Preferred 
polysaccharides are carboxymethylcellulose or sodium alginate. However, 
polymer A can also be a mixture of the polymers described above. Examples 
of preferred mixtures are partially hydrolyzed PVALs and 
carboxymethylcellulose, or partially hydrolyzed PVAL and sodium alginate. 
Polymer A is preferably watersoluble. 
Polymer B is a maleic anhydride (MA) homo- or copolymer or a mixture of MA 
homo- and copolymers or a mixture of various MA copolymers, the hydrolysis 
time being 5 to 120 minutes, preferably 10 to 60 minutes. Hydrolysis time 
is taken to mean the time in minutes in which the pH of a stirred 
dispersion of 0.2 g of polymer B in 76 ml of distilled water and 17.5 ml 
of 0.1 molar NaOH drops from pH 12.4 to pH 10.0 at 25.degree. C. MA 
homopolymers are known and can be prepared, for example, following 
US-A-4789716. Preferably used copolymers are those of MA with alkyl vinyl 
ether, styrene, 2-methylstyrene, monomethoxypolyethylene glycol vinyl 
ethers or olefins, such as ethylene, propylene, isobutylene, etc., and 
similar compounds. Maleic anhydride/methyl vinyl ether (MA/MVE) copolymers 
are particularly preferred. Copolymers of MA with abovementioned compounds 
are known, or they can be prepared following conventional methods, for 
example MA/monomethoxypolyethylene glycol vinyl ether copolymers by the 
method of Tohru Suzuki et al Journal of Polymer Science Polymer Chemistry 
Edition, Vol. 22, 1984, 2829 to 2839. Polymer B is preferably 
water-insoluble. 
In the absorbing polymer according to the invention, the acid anhydride 
groups are present in virtually completely open form and, depending on the 
nature and amount of the base used, a small, but important proportion of 
them is present as ester groups, occasionally as a salt and free acid 
groups, and in some cases also as acid amide groups. The degree of 
neutralization is the proportion of acid functions in mol %, based on the 
total number of acid functions present, which is present as a salt. It is 
about 25 to 80 %. 
The proportion of polymer A in the absorbing polymer according to the 
invention is 10 to 99, preferably between 40 and 95 per cent by weight; 
the proportion of polymer B is 1 to 90, preferably 25 to 60 per cent by 
weight. 
The absorbing polymer according to the invention has an absorption capacity 
for distilled water of at least 110 to 800 g/g of the dry absorbing 
polymer an absorption capacity for a 0 9 percent strength aqueous NaCl 
solution or for an aqueous CI-D standard solution, that is an aqueous 
solution having a defined ion content, which is described in Example 1 of 
the present application, of 10 to 120 g/g of the dry absorbing polymer. 
It is capable of absorption over a wide temperature range which embraces 
the conventional application range of about 0.degree. to 50.degree. C., 
and it is stable in the presence of those liquids which it is to absorb, 
which, besides water, can also be, for example, blood, urine, 
perspiration, secretion of wounds, etc. A particular advantage is the fact 
that it is non-poisonous. 
The invention also relates to a process for the preparation of an absorbing 
polymer, comprising combining an optionally modified polyvinyl alcohol, an 
optionally modified polysaccharide or mixtures of these with a maleic 
anhydride homo- or copolymer having a hydrolysis time of 5 to 120 minutes, 
and the mixture being treated at a temperature of 20 to 120.degree. C. 
with 0.5 to 1.6 equivalents, added all at once, of an inorganic or organic 
base per equivalent of maleic anhydride. 
The preparation of the absorbing polymer according to the invention can be 
continuous or batchwise, and, in a first step, polymer A and polymer B are 
mixed in a solid, dissolved or dispersed form. Suitable diluents or 
solvents are organic solvents which are inert under the reaction 
conditions or water, water being preferred In a preferred procedure, 
polymer A is dissolved in water and polymer B is added in the form of a 
powder or dispersed in water. The two polymer systems are combined and if 
appropriate heated, or the polymer systems A and B are heated before they 
are combined The reaction mixture is treated with an inorganic or organic 
base at temperatures of 20.degree. to 120.degree. C., preferably at 
temperatures of about 50.degree. to 90.degree. C. Inorganic bases which 
can be employed are, for example, alkali metal hydroxides, alkali metal 
hydrogen carbonates, alkali metal carbonates, ammonia, ammonium hydrogen 
carbonate or ammonium carbonate, organic bases which can be employed are, 
for example, amines, such as methylamine, ethylamine, guanidine carbonate 
etc. The base is preferably employed in the form of aqueous solutions. It 
is essential for the process that the base is added all at once, that is 
to say, rapidly and without interruption. 
In general, the solutions or dispersions of polymers A and B are employed 
as concentrated as possible. When the base is added to the reaction 
mixture of polymers A and B, virtually all maleic anhydride groups of 
polymer B are opened, and 0.005 to 5 mol % of the acid functions formed as 
a result of the reaction form an ester bond with the hydroxyl groups of 
polymer A. This results in a network of polymers A and B which is bonded 
via covalent bonds and which has a small but important proportion of 
covalent ester bonds. The number of the covalent ester bonds in the 
absorbing polymer was determined photometrically via dinitrophenyl 
hydrazide, which absorbs at 340 nm. After the reaction, some of the acid 
functions are in the form of a salt and some in the form of a free acid; 
if ammonia or amines are used, amide bonds can additionally also be 
formed. 
Polymer A and polymer B are employed in a ratio by weight of 10:90 to 99:1, 
preferably of about 40:60 to about 95:5. 0.5 to 1.6 equivalents of the 
base are used per equivalent of maleic anhydride in polymer B, so that 
after the reaction 25 to 80 % of the acid functions are present as a salt 
and 0 to 50 % as an amide. The remaining acid functions, which are not 
present in the form of esters, amides or salts, are present in the form of 
free acid groups. 
The reaction time is very short. The rate at which the reaction proceeds 
depends on the nature and concentration of the specifically employed 
starting substances, but in particular on the reaction temperature. At 
room temperature, the reaction proceeds within minutes, at higher 
temperatures within seconds. 
In the course of the reaction, the viscosity of the reaction mixture 
increases greatly. Comparison experiments have revealed that this can 
partly be attributed to "intertwining" of the polymers A and B, as 
described in US-A-4,169,818, but, as an important feature, also to 
moderate esterification of polymers A and B. To this end, reaction 
mixtures according to the invention and comparison reaction mixtures were 
prepared under identical conditions in each case. The only difference 
between these reaction mixtures was that, in the comparison case, the 
anhydride groups of polymer B had already been completely hydrolyzed 
before the base was added, so that esterification with polymer A was no 
longer possible When the viscosities are compared, it becomes evident that 
the viscosity of the reaction mixtures according to the invention is 
substantially higher than the viscosity of the comparison reaction 
mixtures. This can only be explained by the presence of ester bonds 
between polymer A and polymer B. 
To obtain a dried, absorbing polymer according to invention, the gel formed 
in the reaction is applied, for example, to a suitable support surface, 
such as glass, plastic or steel, dried by customary methods, such as, for 
example, heating, drying in the air, drying in vacuo or lyophilization, 
peeled off the support surface and used as a foil, or scraped off and 
comminuted by pounding or grinding so that the absorbing polymer is then 
present in the form of a film, powder or flakes and is ready for use. 
Depending on the field of application, a range of substances such as 
softeners, surface-active substances, fillers, pigments, UV-absorbing 
materials, antioxidants, odour-imparting substances, disinfectants and 
also chemicals suitable for agriculture can be admixed to the dried 
absorbing polymer or to a dispersion or solution of the absorbing polymer 
according to the invention, with the proviso that they do not negatively 
influence the absorption properties of the absorbing polymer according to 
the invention. 
The absorbing polymer according to the invention can be readily and rapidly 
prepared, it is virtually water-insoluble, it is non-poisonous, has very 
good absorption properties, and thus represents an enrichment of the art. 
Accordingly, the absorbing polymer according to the invention can be used 
in the form of a powder or individual pieces, in the form of foils, 
fibres, sheet-like structures and similar shapes, for a range of purposes 
Foils made of the absorbing polymer according to the invention can be 
used, for example, to construct moisture barriers in the soil. A powder 
which consists of the absorbing polymer according to the invention, and 
which can be mixed for example with soil, glass beads, foamed polymers, 
calcined clay or comminuted plastic, improves the water retention 
properties of the soil. It is also possible to incorporate active 
substances into the absorbing polymer according to the invention in any 
customary manner, thus guaranteeing long-term effectiveness of these 
active substances. 
Furthermore, the absorbing polymer can be combined with one or more 
supports to give an absorbing product. 
Supports which are possible are, for example, fibrous supports, such as 
woven or unwoven material, such as, for example, cotton tissue, rayon, 
wool, dressing gauze, paper or cellulose fluff, for example in the form of 
lengths, sheets or loose fibres, preferably lengths of paper; glass, 
ceramics or metal, but also materials such as wood, stone or concrete, are 
also possible. 
The absorbing polymer can be applied to the support on one side or both 
sides, or incorporated and/or applied between several identical or 
different supports, so that laminates are present which have two or more 
layers of the absorbing polymer or it is present in connection with loose 
fibres, such as, for example, cellulose fibres, asbestos fibres or other 
material, in which case it can be encased between cover sheets, for 
example of fabric, fleece fabric or paper. It can be applied to the 
support continuously or batchwise, that is to say, in the form of, for 
example, strips, dots, lattices etc., or it can be incorporated between 2 
or more supports. 
Products which are preferred are, for example, products which are used in 
the sanitary sector, such as, for example, household and industrial 
tissues, for example, tissue papers , sanitary towels, tampons, surgical 
sponges or swabs, facial tissues, bandages, swathes etc. 
Such absorbing products can be prepared in various manners. The support can 
be immersed into a dispersion of the absorbing polymer according to the 
invention in a conventional manner and dried, the dispersion can be 
sprayed onto the support or supports, or the absorbing polymer is 
scattered onto the support in the form of a powder and adhesively bonded 
with the support by suitable measures, such as, for example, steam and/or 
pressure treatment. To coat fibres, polymer A, polymer B and--all at 
once--the base can be incorporated into a suspension of fibres, so that 
the absorbing product is formed directly in the reaction mixture. 
Furthermore, it is possible to spray polymer A, polymer B and the base in 
solution or dispersion onto a continuously moving length of support. In 
this case, polymer A, polymer B and the base can be sprayed on either 
individually or together. 
In a particularly preferred embodiment, an aqueous solution of polymer A is 
combined with polymer B which is employed in the form of a powder in 
aqueous dispersion. This dispersion and the solution of the base, both of 
which are as concentrated as possible, are propelled through nozzles with 
the aid of pressurized air or steam and sprayed onto the support. In this 
case, the base can be mixed with polymer A and polymer B either within the 
nozzle or outside the nozzle If a length of paper is used as the support, 
and if the reaction mixture is applied in a highly concentrated form and 
only in small amounts, it is possible for in particular an overdried paper 
to take up the entire moisture. 
If the support contains free hydroxyl groups, such as, for example, in the 
case of cellulose-containing supports, the former can be involved in the 
crosslinking process so that particularly good bonding to the support 
takes place when the absorbing layer is formed. 
The absorbing products have excellent absorption properties, the bonding 
between support and polymer being good and durable, and they can be 
prepared easily, rapidly and with a low input of energy and costs, and 
therefore represent an enrichment of the art.

EXAMPLE 1 
Maleic anhydride/methyl vinyl ether (MA/MVE copolymer) 
87.3 g of maleic anhydride and 1.46 g of dilauroyl peroxide were introduced 
into a 2 1 Juchheim pressurized reaction vessel, and the reaction 
apparatus was then flushed with nitrogen. When the apparatus was free from 
oxygen, 310 g of methyl vinyl ether which had been dried over solid sodium 
hydroxide and freshly distilled, were added. The reaction mixture was 
warmed to 55.degree. C. with stirring and maintained at this temperature 
for 2 hours under pressure. After the mixture had cooled to 20.degree. C., 
excess methyl vinyl ether was distilled off, and the reaction product was 
removed from the vessel. This gave 118 g (84.9 % of theory) of an MA/MVE 
copolymer having the following properties: loss on drying at 105.degree. 
C.: 0.92 %, at 60.degree. C. in vacuo: 0.25 %. The particle size 
distribution, which was measured by sieve analysis, gave the following 
values: 
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Particle size (micrometers) 
(%) 
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below 32 43.6 
32-44 7.6 
44-100 13.0 
100-200 14.0 
200-354 14.2 
354-500 5.8 
500-710 0.6 
710-850 0.6 
850-1400 0.6 
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Conditions: Alpine air-jet sieve, 0.02 bar vacuum; sieving time: 7 minutes 
The specific viscosity was determined as follows: 0.5 g of MA/MVE 
copolymer was dissolved in 50 ml of methyl ethyl ketone and the solution 
was stirred for 1 to 2 hours at room temperature. The specific viscosity 
was measured with the aid of a Ubbelohde viscometer and was 3.2. 
The hydrolysis rate of the MA groups was determined as follows: 
17.5 ml of a 0.1 molar aqueous sodium hydroxide solution and 76 ml of 
distilled water (having a pH of 12.4) were dispersed with 0.2 g of MA/MVE 
copolymer in a 250 ml round-bottomed flask equipped with a KPG stirrer 
(blade diameter: 5 cm) at 250 rpm. The pH drop in the measuring apparatus 
was determined with the aid of a glass electrode. The hydrolysis time is 
defined as the period in minutes which is required for the pH to drop from 
pH 12.4 to pH 10.0. The hydrolysis rate was 30 minutes. 
EXAMPLE 2 
Polymer A: Polyvinyl alcohol (PVAL), Mowiol 8-88, Hoechst, FRG 
Polymer B: Maleic anhydride/methyl vinyl ether (MA/MVE) copolymer of 
Example I 
100 g of 5 % by weight aqueous solution of polymer A were heated to 
80.degree. C and treated with 5 g of polymer B in the form of a powder, 
with stirring 30 ml of a 1 molar aqueous sodium hydroxide solution were 
then added all at once, which resulted in gel formation in the reaction 
vessel within one minute. The gel was brushed onto a plastic foil and 
dried at 100.degree. C. 0.17 mol % of the acid functions of polymer BL 
were present in the form of esters. The absorption properties of the dried 
gel were determined in the following manner: 
The dried gel was scraped off the plastic foil. About 0.2 g were 
transferred into a teabag and immersed in an aqueous test solution. The 
test solutions used were, on the one hand, distilled water, on the other 
hand a CI-D standard solution which is an aqueous solution having an 
exactly defined ion content (CI, Handbook, Vol. 1, Analysis of 
Technical Formulated Pesticides, R. Ashworth, J. Henriet, J. F. Lovett, 
Cellaboration International Pesticide, Analytical Council, 1970, 875 to 
879), and a 0.9 % by weight NaCl solution After 24 hours, the teabag was 
removed from the test solution, placed on a filter paper base and turned 
without application of pressure until the escape of liquid had ceased 
(about 4 minutes). After this, the weight of the swelled sample was 
determined. The absorption capacity AC of the polymerized substance for a 
test solution was calculated as follows: 
##EQU1## 
AC-D is the absorption capacity for distilled water AC-C is the absorption 
capacity for a CI-D standard solution 
AC-N is the absorption capacity of a 0.9 % by weight sodium chloride 
solution 
The gel had the following absorption properties: 
AC-D: 434 
AC-C: 49 
AC-N: 49 
The same procedure was also used for determining the absorption capacities 
of the absorbing polymer in the other examples. 
EXAMPLE 3 
Polymer A: PVAL, Mowiol 4-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
A 27 % by weight aqueous solution of polymer A was introduced in a mixing 
vessel at a flow of 7.4 g/min together with polymer B in the form of a 
powder, in an amount of 2 g/min, and the mixture was homogenized. The 
dispersion which formed was continuously withdrawn in an amount of 9.4 
g/min, heated to 80.degree. C., mixed with 4 ml/min of a 17 % by weight 
aqueous sodium carbonate solution, immediately sprayed onto a paper length 
of width 23 cm, moving at 12.4 m/min, and dried with hot air. To measure 
the absorption properties of the absorbing product, batches of 3 to 7 
samples in the shape of circles were punched out of the coated length of 
paper, immersed in test solutions as described in Example 1 and then 
treated as in Example 1. The absorption capacity of the absorbing product 
for a test solution was calculated as follows: 
##EQU2## 
The absorbing product had the following absorption properties: 
AC-D 244 
AC-C: 41 
The same procedure was used for determining the absorption capacity of the 
absorbing products in the other examples. 
EXAMPLE 4 
Polymer A: PVAL, Mowiol 4-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
100 g of a 24.8 % by weight aqueous solution of polymer A were heated to 
80.degree. C. and treated with 24.8 g of polymer B in the form of a 
powder, with stirring. After this, 39.4 g of a 20 % by weight aqueous 
sodium carbonate solution were added all at once. After about 30 seconds, 
the reaction mixture started foaming, this resulting in the formation of a 
foamed product which was brushed on and dried at 100.degree. C. 
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Without support 
On paper 
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AC-D 214 203 
AC-C 30 19 
AC-N 34 -- 
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EXAMPLE 5 
Polymer A: PVAL, Mowiol 4-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
The procedure of Example 2 was followed, but at a reaction and drying 
temperature of 25.degree. C., this giving a dried gel having the following 
properties: 
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Without support 
On paper 
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AC-D 142 191 
AC-C 31 25 
AC-N 38 -- 
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0.084 mol % of the acid functions of polymer B were present in the form of 
an ester. 
EXAMPLE 6 
Polymer A: PVAL, Mowiol 8-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
50 g of a 10 % by weight solution of polymer A were warmed to 80.degree. C. 
and treated with 1 g of polymer B, with stirring. After this, 30 ml of a 1 
molar aqueous ammonium hydrogen carbonate solution were added all at once, 
which made the reaction mixture foam, and a foamed product was formed. 
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Without support 
On paper 
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AC-D 393 140 
AC-C 36 12 
AC-N 33 -- 
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EXAMPLE 7 
As described in Example 6, but using 30 ml of a 0.5 molar, aqueous 
guanidine carbonate solution as the base, a gel being obtained. 
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On paper 
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AC-C 24 
AC-N: 34 
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EXAMPLE 8 
Polymer A: Carboxymethylcellulose (CMC), Cekol-DVEP Type, Billerud, Sweden; 
Polymer B: MA/MVE copolymer of Example 1 
100 g of a 5 % by weight solution of polymer A were heated to 80.degree. C. 
and treated with 5 g of polymer B, with stirring. A gel was formed within 
one minute by adding 30 ml of a 1 molar aqueous sodium hydroxide solution 
all at once. 
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Without support 
On paper 
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AC-D 55 65 
AC-C 64 -- 
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EXAMPLE 9 
Polymer A: Sodium alginate, Protanal LF 20/60, AMEA, Austria 
Polymer B: MA/MVE copolymer of Example 1 
4.5 g of polymer A and 4.5 g of polymer B were run into 145 ml of distilled 
water, and the mixture was then heated to 70.degree. C. with stirring A 
gel was formed in the course of 2 minutes by adding 28.8 ml of a 1 molar 
aqueous sodium hydroxide solution all at once. 
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Without support 
On paper 
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AC-D 208 214 
AC-C 72 68 
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EXAMPLE 10 
Polymer A: Hydroxypropyl starch, Solamyl 9570, AGENA, Austria 
Polymer B: MA/MVE copolymer of Example 1 
The procedure of Example 9 was followed, but using 160 ml of distilled 
water, 12 g of polymer A, 6 g of polymer B and 53.8 ml of a 1 molar 
aqueous sodium hydroxide solution. 
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Without support 
On paper 
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AC-D 220 180 
AC-C: 26 -- 
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EXAMPLE 11 
Polymer A: Cold-soluble starch, Sobex 242, Sudstarke, FRG 
Polymer B: MA/MVE copolymer of Example 1 
The procedure of Example 9 was followed, but using 160 ml of water, 6 g of 
polymer A, 3 g of polymer B and 26.9 ml of a 1 molar, aqueous sodium 
hydroxide solution. 
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Without support 
On paper 
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AC-D 227 123 
AC-C 20 -- 
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EXAMPLE 12 
Polymer A: Phosphate guar, Meyprofilm 500, Meyhall, Switzerland 
Polymer B: MS/MVE copolymer of Example 1 
The procedure of Example 9 was followed, but using 160 ml of water, 6 g of 
polymer A, 6 g of polymer B and 38.4 ml of 1 molar aqueous sodium 
hydroxide solution. 
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Without support 
On paper 
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AC-D 152 215 
AC-C 18 28 
AC-N 22 -- 
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EXAMPLE 13 
Polymer A: Depolymerized guar, Meyprogat 90, Meyhall, Switzerland 
Polymer B; MA/MVE copolymer of Example 1 
The procedure of Example 9 was followed, but using 160 ml of water, 3 g of 
polymer A, 3 g of polymer B and 19.2 ml of a 1 molar aqueous sodium 
hydroxide solution. 
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Without support 
On paper 
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AC-C 25 14 
AC-N 12 -- 
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EXAMPLE 14 
Polymer A: Native guar, Meyproguar CSA 200/50, Meyhall, Switzerland 
Polymer B: MA/MVE copolymer of Example 1 
The procedure of Example 9 was followed, but using 160 ml of water, 3 g of 
polymer A, 3 g of polymer B and 26.9 ml of a 1 molar aqueous sodium 
hydroxide solution. 
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Without support 
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AC-D 113 
AC-C 23 
AC-N 22 
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EXAMPLE 15 
Polymer A: Hydroxypropyl starch, Solamyl 9570, AGENA, Austria, and PVAL, 
Mowiol 4-88, Hoechst, FRG, in the ratio of 1:1 
Polymer B: MA/MVE copolymer of Example 1 
50 g of a 5 % by weight aqueous hydroxypropyl starch solution was made into 
a paste and treated at room temperature with 12.5 g of a 20 % by weight 
PVAL solution, and the mixture was heated to 80.degree. C., after which 5 
g of polymer B were added with stirring. A gel was formed within one 
minute after 30 ml of a 1 molar aqueous sodium hydroxide solution were 
added all at once. 
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Without support 
On paper 
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AC-D 308 247 
AC-C 28 22 
AC-N 32 -- 
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EXAMPLE 16 
Polymer A: Cold-soluble starch, Sobex 242, Sudstarke, FRG, and PVAL, Mowiol 
4-88, Hoechst, FRG, in the ratio by weight of 1:1 
Polymer B MA/MVE copolymer of Example 1 
50 g of a 5 % by weight aqueous starch solution were mixed with 12.5 g of a 
20 % by weight aqueous PVAL solution, and the mixture was heated to 
80.degree. C and treated with 5 g of polymer B in the form of a powder. A 
gel was formed after 30 ml of a 1 molar aqueous potassium hydroxide 
solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 259 138 
AC-C 28 15 
AC-N 27 -- 
______________________________________ 
EXAMPLE 17 
Polymer A: Sodium alginate, Protanal LF 20/60, AMEA, Austria, and PVAL, 
Mowiol 4-88, Hoechst, FRG 
Polymer B: MA-MVE copolymer of Example 1 
100 ml of a 3 % by weight aqueous sodium alginate solution and 7.5 g of a 
20 % by weight aqueous PVAL solution were mixed at room temperature, and 
the mixture was heated to 80.degree. C. and treated with 4.5 g of polymer 
B in the form of a powder. A gel was formed after 27 ml of a 1 molar 
aqueous sodium hydroxide solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 250 220 
AC-C 67 52 
______________________________________ 
EXAMPLE 18 
The procedure of Example 17 was followed, the ratio by weight of the 
starting substances sodium alginate:PVAL:MA/MVE copolymer being 1:1:2. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 319 277 
AC-C 52 50 
______________________________________ 
EXAMPLE 19 
The procedure of Example 17 was followed, the ratio by weight of the 
starting substances sodium alginate:PVAL:MA/MVE copolymer being 1:0.5:1.5. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 333 236 
AC-C 48 43 
______________________________________ 
EXAMPLE 20 
Polymer A: Carboxymethylcellulose (CMC), CEKOL HDEG,Billerud, Sweden, and 
PVAL, Mowiol 4-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
80 g of a 4 % by weight aqueous solution of CMC and 16 g of a 20 % by 
weight aqueous solution of PVAL were heated to 82.degree. C. and treated 
with 6.4 g of polymer B in the form of a powder. A gel was formed within 1 
minute after 38.4 ml of a 1 molar aqueous sodium hydroxide solution were 
added all at once 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 289 383 
AC-C 64 39 
AC-N 55 -- 
______________________________________ 
EXAMPLE 21 
Polymer A: Hydrolyzed wheat starch, Merigum C, Amylum, Belgium, and PVAL, 
Mowiol 8-88, Hoechst, FRG 
Polymer B: MA/MVE copolymer of Example 1 
6 g of wheat starch and 6 g of PVAL were made into a paste or dissolved, 
respectively, in 123 ml of distilled water at 82.degree. C., after which 6 
g of MA/MVE copolymer, dispersed in 20 ml of water, were added with 
stirring. A gel was formed within 30 to 50 seconds after 39 ml of a 1 
molar aqueous sodium hydroxide solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 374 188 
AC-C 18 16 
AC-N 18 -- 
______________________________________ 
EXAMPLE 22 
Polymer A: Cationic potato starch, Cationamyl 9852, AGENA, Austria, and 
xanthan gum, Jungbunzlauer, Austria, 
Polymer B: MA/MVE copolymer of Example 1 
6 g of potato starch and 3 g of xanthan gum were made into a paste or 
dissolved, respectively, in 140 ml of distilled water at 80.degree. C., 
and treated with 3 g of polymer B which had been dispersed in 20 ml of 
water. A gel was formed within 30 seconds after 27 ml of a 1 molar aqueous 
sodium hydroxide solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 144 113 
AC-C 19 25 
AC-N 17 -- 
______________________________________ 
EXAMPLES 23-27 
3 g of a range of comminuted cellulose materials were incorporated in 100 g 
of a 5 % by weight PVAL solution (Mowiol 8-88, Hoechst, FRG), and the 
mixture was stirred to form fine fibres This mixture was heated to 
80.degree. C. and treated with 8 g of MA/MVE copolymer of Example 1. A gel 
was formed within 20 seconds after 48 ml of a 1 molar aqueous sodium 
hydroxide solution were added all at once. 
EXAMPLE 23 
Cellulose material Photocellulose, Borregaard, Austria 
PVAL:Cellulose:MA/MVE copolymer =1:0.6:1.6 (5 g:3 g:8 g) 48 ml of 1 molar 
NaOH 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 334 254 
AC-C 24 23 
AC-N 18 -- 
______________________________________ 
EXAMPLE 24 
Cellulose material: Sulphatecellulose, degree of freeness 12.degree. SR, 
whiteness 88.7 %, Pols, Austria 
PVAL:Cellulose:MA/MVE copolymer =1:0.6:1.6 (5 g:3 g:8 g) 
48 ml of 1 molar NaO 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 390 256 
AC-C 25 19 
AC-N 18 -- 
______________________________________ 
EXAMPLE 25 
Cellulose material:tissue paper. A, Zewa, PWA FRG PVAL:Cellulose:MA/MVE 
copolymer =1:0.6:1.6 (5 g:3 g:8 g) 48 ml of 1 molar NaOH 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 284 251 
AC-C 29 27 
AC-N 22 -- 
______________________________________ 
EXAMPLE 26 
Cellulose material: tissue paper B. Henry, Laakirchen, Austria 
PVAL:Cellulose:MA/MVE copolymer =1:1:2 (5 g:5 g: 10 g) 60 ml of 1 molar 
NaOH 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 227 196 
AC-C 23 28 
AC-N 23 -- 
______________________________________ 
EXAMPLE 27 
Cellulose material, sulphite cellulose, fully bleached Steyrermuhl, Austria 
PVAL:Cellulose:MA copolymer = 1:1:2 (5 g:5 g:10 g) 60 ml of 1 molar NaOH 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 218 204 
AC-C 20 18 
AC-N 17 -- 
______________________________________ 
0.113 mol % of the acid functions of polymer B were present in the form of 
esters. 
EXAMPLE 28 
PVAL succinate 
100 g of a 36 % by weight aqueous PVAL solution (Mowiol 4-88, Hoechst, FRG) 
were stirred with 24.5 g of succinic anhydride and 0.3 g of concentrated 
sulphuric acid for 1 hour at 60.degree. C. The reaction mixture was then 
cooled to room temperature and added dropwise to acetone, PVAL succinate 
being precipitated. The precipitate was filtered off, washed with acetone 
and dried at 50.degree. C. to constant weight This gave 45 g of PVAL 
succinate. The degree of substitution DS was determined titrimetrically. 
The degree of substitution was 0.149 mol of succinic ester groups per mol 
of hydroxyl groups in the PVAL. 
PVAL succinates having degrees of substitution of 0.016; 0.038; 0.091 and 
0.293 mol of succinic ester groups per mol of hydroxyl groups in the PVAL 
were prepared following the above procedure using appropriate amounts of 
succinic anhydride. 
Compounds 29 to 33 were prepared following the procedure of Example 2 and 
using, in each case, 5 g of PVAL succinate of the appropriate degree of 
substitution DS, 5 g of polymer B and 30 ml of 1 molar aqueous sodium 
hydroxide solution: 
EXAMPLE 29-33 
Polymer A: PVAL succinate of degree of substitution DS 
Polymer B: MA/MVE copolymer of Example 1 
______________________________________ 
AC-D AC-C AC-N 
without without 
without 
No. DS support support 
support 
______________________________________ 
29 0.016 431 54 50 
30 0.038 398 61 52 
31 0.091 353 64 48 
32 0.149 400 64 41 
33 0.293 424 61 43 
______________________________________ 
EXAMPLE 34 
PVAL hydroxypropanesulphonic acid ether 
100 g of a 20 % by weight aqueous solution of PVAL, Mowiol 8-88, Hoechst, 
FRG, were treated with 17.8 g of a 25 % by weight aqueous solution of Na 
3-chloro-2 -hydroxypropanesulphonate (Na CHPS), and the mixture was heated 
to 60.degree. C. In this process, the pH was maintained at 8 by dropwise 
addition of a 20 % by weight aqueous sodium hydroxide solution. When the 
reaction was complete, the reaction solution was added dropwise to 
acetone, PVAL hydroxypropanesulphonic acid ether being precipitated. The 
precipitate was filtered off, washed with acetone and dried. This gave 21 
g of PVAL hydroxypropanesulphonic acid ether. PVAL hydroxypropanesulphonic 
acid ethers were prepared following the above procedure using appropriate 
amounts of 3-chloro-2-hydroxypropanesulphonic acid ether. 
The following polymerized substances were prepared following the procedure 
described in Example 2 using 120 ml of a 1 molar aqueous sodium hydroxide 
solution, in each case 20 g of PVAL hydroxypropanesulphonic acid ether as 
polymer A, dissolved in 80 ml of distilled water, and in each case 20 g of 
MA/MVE copolymer as polymer B, prepared in Example 1: 
EXAMPLES 35-39 
______________________________________ 
AC-D 
Amount of with- 
NaCHPS out AC-C AC-N 
(25% b.w.) 
sup- On without 
On without 
No. in g port paper support 
paper support 
______________________________________ 
35 3.57 423 347 37 36 34 
36 17.84 462 293 47 30 50 
37 39.59 326 245 28 20 28 
38 107.08 268 398 34 24 43 
39 278.48 337 358 34 26 35 
______________________________________ 
EXAMPLE 40 
PVAL 2-hydroxypropane-3-(trimethylammonium chloride) ether 
0.40 g of glycidyltrimethylammonium chloride were stirred into 200 ml of a 
5 % by weight aqueous solution of PVAL, Mowiol 8-88, Hoechst, FRG, of 
Example 1 at room temperature, and the reaction mixture was heated to 
60.degree. C and maintained at pH 8 by continuous addition of an aqueous 
sodium hydroxide solution After 2 hours, the reaction mixture was cooled 
to room temperature, and the product formed was precipitated by adding 
acetone, filtered off, washed and dried at 50.degree. C. This process gave 
10.4 g of the title compound. 
EXAMPLE 41 
A product having the following properties was obtained following the 
procedure described in Example 2 and using 5 g of the product of Example 
40, dissolved in 100 ml of distilled water, 5 g of MA/MVE copolymer 
prepared in Example 1 in the form of a powder and 30 ml of a 1 molar 
aqueous sodium hydroxide solution. 
______________________________________ 
Without support 
______________________________________ 
AC-D 373 
AC-C 35 
AC-N 51 
______________________________________ 
EXAMPLE 42 
6 g of cationic potato starch (Amylofax 15, DS =0.027, AVEBE, NL) and 6 g 
of PVAL (Mowiol 8-88, Hoechst, FRG) were made into a paste, or dissolved, 
respectively, in 123 ml of water at 82.degree. C., and the mixture was 
treated with 6 g of MA/MVE copolymer, prepared in Example 1, and dispersed 
in 20 ml of water. A gel was formed within seconds after 39 ml of 1 molar 
aqueous sodium hydroxide solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 253 159 
AC-C 18 16 
AC-N 16 -- 
______________________________________ 
EXAMPLE 43 
6 g of cationic potato starch (Amylofax 15, DS = 0.027, AVEBE, NL) and 3 g 
of CMC (CEKOL HDEG, Billerud, Sweden), were made into a paste, or 
dissolved, respectively, in 140 ml of distilled water at 80.degree. C., 
and the mixture was treated with an aqueous dispersion of 3 g of MA/MVE 
copolymer, prepared in Example 1, in 20 ml of water. A gel was formed 
within a few seconds after 27 ml of 1 molar aqueous sodium hydroxide 
solution were added all at once. 
______________________________________ 
Without support 
On paper 
______________________________________ 
AC-D 230 156 
AC-C 32 30 
______________________________________ 
EXAMPLE 44 
Polymer A: Cationic potato starch, Cationamyl 9852, AGENA, Austria 
Polymer B MA/isobutyl-ene copolymer, Isobam-10, Kuraray, Japan 
6 g of polymer A were made into a paste in 160 ml of distilled water at 
70.degree. C., and the mixture was treated with stirring with 3 g of 
polymer B which had previously been ground in a porcelain dish. A gel was 
formed after 26.5 ml of a 1 molar aqueous ammonium hydroxide solution were 
added all at once. 
______________________________________ 
Without support 
______________________________________ 
AC-D 127 
______________________________________ 
The examples 45 to 48 below prove that the polymerized substance according 
to the invention is crosslinked via ester bonds and not only via hydrogen 
bonds. 
EXAMPLE 45 
1 g of cationic potato starch, Cationamyl 9852, AGENA, Austria, were made 
into a paste in 150.6 g of distilled water at 70.degree. C. for 20 minutes 
and the mixture was treated with 0.5 g of MA/MVE copolymer, prepared in 
Example 1, and dispersed in 9.5 ml of distilled water, and the mixture was 
stirred for 30 seconds, after which 3.84 ml of a 1 molar aqueous sodium 
hydroxide solution were added all at once which resulted in the formation 
of a gel. The solids content of the reaction mixture 
##EQU3## 
was 1 % in this case. After the reaction mixture had cooled to room 
temperature, the viscosity was determined. 
Reaction mixtures of solids contents of 2 % and 3 % were prepared in the 
same manner using the appropriate amounts of starting substances. 
For comparison, reaction mixtures having solids contents of 1, 2 and 3 % 
were prepared in the same manner but using a MA/MVE copolymer, prepared in 
Example 1, in which the acid anhydride groups were hydrolyzed completely 
prior to addition to the reaction mixture by stirring in distilled water 
for 14 hours, and the viscosities of these reaction mixtures were 
determined. The degree of neutralization was 60 % in all cases, that is to 
say, 60 % of the acid groups in the polymerized substance were present in 
the form of the Na salt, and the pH was 7.5. 
The viscosity was determined with the aid of a Brookfield Viscometer, 
Synchro Lectric Viscometer, Model LVT. The following viscosities were 
measured: 
______________________________________ 
Viscosity in mPas 
Solids content 
According to 
in percent the invention 
Comparison 
______________________________________ 
1 520 120 
2 8350 525 
3 339000 2190 
______________________________________ 
EXAMPLE 46 
2 g of polyvinyl alcohol, Mowiol 8-88, Hoechst, FRG, were dissolved in 89.1 
g of distilled water at 80.degree. C., and the solution was treated with 1 
g of MA/MVE copolymer, prepared in Example 1, and dispersed in 9 ml of 
water, and the mixture was stirred for 30 seconds, after which 3.2 ml of a 
1 molar aqueous sodium hydroxide solution were added all at once, which 
resulted in the formation of a gel. The solids content of the reaction 
mixture was 3 %. After the reaction mixture had cooled to room 
temperature, the viscosity was determined. 
Reaction mixtures having solids contents of 5 % and 7 % were prepared in 
the same manner using the appropriate amounts of starting substances, and 
the viscosities of these reaction mixtures were measured. 
For comparison, reaction mixtures were prepared in the same manner, but 
using a MA/MVE copolymer, prepared in Example 1, in which the acid 
anhydride groups were completely open prior to the addition to the 
reaction mixture by stirring in distilled water for 14 hours, and the 
viscosities of these reaction mixtures were determined. The degree of 
neutralization was 25 % in all cases and the pH was 4.05. 
______________________________________ 
Viscosity in mPas 
Solids content 
According to 
in percent the invention 
Comparison 
______________________________________ 
3 1660 158 
5 7945 550 
7 36310 1740 
______________________________________