DE4038908A1 - USE OF WATER-SOLUBLE GRAFTED NATURALS AS WATER TREATMENT AGENTS - Google Patents

Abstract

Described is the use, as water-treatment agents, of water-soluble graft polymers obtained by the radical-initiated polymerization of (A) monomer mixtures containing as monomers monoethylenically unsaturated carboxylic acids, their alkali-metal salts and/or their ammonium salts, in the presence of (B) monosaccharides, oligosaccharides, polysaccharides, oxidatively, hydrolytically or enzymatically degraded polysaccharides, chemically modified mono-, oligo- or polysaccharides, or mixtures of these compounds, in the ratio, by mass, of A:B of (95 to 20):(5 to 80).

Description

The invention relates to the use of water-soluble grafted Natural products obtained by polymerizing monoethylenically unsaturated Carboxylic acids and optionally other monomers in the presence of Monosaccharides, oligosaccharides, polysaccharides and / or derivatives of which are available as water treatment agents.

From US-PS 38 10 834 it is known that hydrolyzed polymalein acid anhydrides, which have a molecular weight of 300 to before hydrolysis 5000, or their water-soluble salts as water treatment agents can be used to largely suppress scale formation or to prevent. The suitable polymers are made by polymerisation ren of maleic anhydride in toluene using benzoyl peroxide and subsequent hydrolysis of the polymaleic anhydride thus obtained produced. Because the polymerization of maleic anhydride is not full constantly and the separation of unpolymerized maleic anhydride of the polymer is difficult, the polymaleic acids still contain considerable amounts of maleic acid.

From US-PS 37 55 264 low molecular weight copolymers are known 85 to 99 mol% maleic anhydride and to supplement 100 mol% acrylic Acid, vinyl acetate, styrene or a mixture thereof is copolymerized The copolymers are obtained by copolymerizing maleic acid hydride in dry organic solvents with the monomers mentioned at temperatures of 100 to 145 ° C in the presence of peroxides. Peroxides include, for example, di-tertiary butyl peroxide, acetyl peroxide, Dicumyl peroxide, diisopropyl percarbonate and especially benzoyl peroxide in Consider. The anhydride groups of the copolymer can according to the poly merization hydrolyzed to acid groups or converted into the salts will. The water-soluble copolymers are used to prevent the Scale deposition used. Those obtainable by this procedure Products have a very high content of unpolymerized malein acid anhydride.

The use of low molecular weight polymers of acrylic acid Water treatment or as a scale inhibitor is from, for example US-PS 39 04 522 and US-PS 35 14 376 known. From US-PS 37 09 816 it is known that copolymers containing acrylamidopropanesulfonic acid are suitable as water treatment agents. For example, come Copoly merisate from 2-acrylamidopropanesulfonic acid and acrylamide into consideration, the  is partially hydrolyzed. The disadvantage here is that the inevitable rest monomeric proportions of acrylamide remain in the polymers, causing their Use can only be recommended to a very limited extent. Homopolymers acrylic acid, on the other hand, has a satisfactory effect only on relative easy-to-suppress cover types, such as B. calcium carbonate.

From JP-A-61/0 31 498 detergents are known, which as a builder 0.5 to 50% by weight of graft polymers from a monosaccharide and / or one Oligosaccharide and a water-soluble ethylenically unsaturated monomer contain. According to the examples, acrylic acid was based on sucrose or Glu grafted.

From the unpublished DE-A-40 03 172 are graft copolymers of monosaccharides, oligosaccharides, polysaccharides and their derivatives known. The graft copolymers are obtainable by free radicals initiated copolymerization of

• (A) monomer mixtures
  • a) 90 to 10% by weight of monoethylenically unsaturated C ₄ to C ₈ dicarboxylic acids, their anhydrides or alkali and / or ammonium salts,
  • b) 10 to 90% by weight of monoethylenically unsaturated C ₃ to C ₁₀ carboxylic acids or their alkali and / or ammonium salts,
  • c) 0 to 40% by weight of other monoethylenically unsaturated monomers which are copolymerizable with the monomers (a) and (b), and
  • d) 0 to 5% by weight of at least two ethylenically unsaturated non-conjugated double bonds in the molecule having monomers

in the presence of

• B) monosaccharides, oligosaccharides, polysaccharides, oxidative, hydrolytically or enzymatically degraded polysaccharides, oxidized hydrolytically or oxidized enzymatically degraded polysaccharides, chemically modified mono-, oligo- and polysaccharides or Mixtures of the compounds mentioned

in the weight ratio (A): (B) from (95 to 20): (5 to 80). The graft co polymers are used as additives to detergents and cleaning agents in quantities from 0.1 to 20% by weight, based on the respective formulations used.

The invention has for its object agents for water treatment to provide the effect of the previously used poly achieve or even surpass merisates based on acrylic acid and can be produced with the partial use of renewable raw materials.

The object is achieved with the use of water soluble graft polymers of monosaccharides, oligosaccharides, poly saccharides and their derivatives, which are available through radical initiated polymerization of

• A) Mixtures of monomers
  • a) 40 to 100 wt .-% monoethylenically unsaturated C ₃ - to C ₁₀ -monocarboxylic acids and / or monoethylenically unsaturated C ₄ - to C ₈ -dicarboxylic acids, their anhydrides, alkali salts and / or ammonium salts
  • b) 0 to 60% by weight of other monoethylenically unsaturated monomers which are copolymerizable with the monomers (a), and
  • c) 0 to 5% by weight of at least 2 ethylenically unsaturated, non-conjugated double bonds in the molecule having monomers

in the presence of

• B) monosaccharides, oligosaccharides, polysaccharides, oxidative, hydro lysed or enzymatically degraded polysaccharides, oxidized hydro lytically or oxidized enzymatically degraded polysaccharides, chemically modified mono-, oligo- and polysaccharides or Mixtures of the compounds mentioned

in the weight ratio (A): (B) from (95 to 20): (5 to 80) as water means of action.

The graft polymers are by homo- or copolymerization of Monomers (A) available in the presence of natural products (B).

Monoethylenically unsaturated C ₃ -C ₁₀ -monocarboxylic acids and their alkali and / or ammonium salts are considered as monomers of group (a). These monomers include, for example, acrylic acid, methacrylic acid, dimethylacrylic acid, ethyl acrylic acid, allylacetic acid and vinyl acetic acid. From this group of monomers, preference is given to using acrylic acid, methacrylic acid, their mixtures and the sodium, potassium or ammonium salts or mixtures thereof. These monomers are polymerized either alone or as a mixture with monoethylenically unsaturated dicarboxylic acids or their anhydrides in the presence of natural products (B). Such dicarboxylic acids contain 4 to 8 carbon atoms, e.g. B. maleic acid, fumaric acid, itaconic acid, mesaconic acid, methylene malonic acid, citraconic acid, maleic anhydride, itaconic anhydride and methylene malonic anhydride. The monoethylenically unsaturated C ₄ to C ₈ dicarboxylic acids can be used in the form of the free acids or in a form neutralized with alkali metal bases, ammonia or amines in the graft polymerization. Of the dicarboxylic acids or their anhydrides in question, maleic acid, maleic anhydride, itaconic acid or itaconic anhydride and the sodium, potassium or ammonium salts of maleic acid or itaconic acid are preferably used. These salts are available, for example, from maleic anhydride or itaconic anhydride if the anhydrides mentioned are neutralized in aqueous solution with sodium hydroxide solution, potassium hydroxide solution or ammonia or amines. The dicarboxylic acids mentioned or their anhydrides or their salts can also be polymerized alone in the presence of the natural products (B).

Such are of particular application technology interest Graft polymers which are obtained by copolymerization of

• 1) 10 to 90, preferably 12 to 80% by weight of monoethylenically unsaturated C ₄ to C ₈ dicarboxylic acids, their anhydrides, salts or mixtures with
• 2) 90 to 10, preferably 88 to 20% by weight of monoethylenically unsaturated C ₃ to C ₁₀ monocarboxylic acids, their alkali metal or ammonium salts or mixtures of the free acids and the salts

are available in the presence of natural substances (B). Technically interesting are in particular graft copolymers which are obtained by copolymerization of

• 1) 15 to 60 wt .-% maleic acid, itaconic acid or their alkali or Ammonium salts with
• 2) 85 to 40 wt .-% acrylic acid, methacrylic acid, mixtures of acrylic acid and methacrylic acid, its alkali or ammonium salts or mixtures of free acids and salts

are available in the presence of natural substances (B).  

The monomers of group (a) can optionally together with (b) other monoethylenically unsaturated monomers which are mixed with the monomers (a) are copolymerizable, are subjected to the graft copolymerization. The The proportion of the monomers (a) in the monomer mixture (A) is 40 to 100% by weight, while the monomers (b) up to 60% by weight are present therein can.

The monomers of group (b) which are used where appropriate in the graft copolymerization include, for example, C ₁ - to C ₆ -alkyl and hydroxyalkyl esters of the compounds mentioned under (a), for. B. methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, maleic acid mono methyl ester, maleic acid dimethyl ester, maleic acid monoethyl ester, maleic acid diethyl ester, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxy butyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate. In addition, the amides and N-substituted alkylamides of the compounds indicated under (a) are suitable as monomers of group (b), for. B. acrylamide, methacrylamide, N-alkylacrylamides with 1 to 18 carbon atoms in the alkyl group, such as N-methylacrylamide, N-dimethylacrylamide, N-tert-butylacrylamide, N-octadecylacrylamide, maleic acid monoethylhexyl amide, maleic acid monododecylamide, dimethylamino propyl methacrylamide and dimethyl aminopropyl methacrylamide. Also suitable as monomers (b) are alkylamino alkyl (meth) acrylates, e.g. B. dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylate and dimethylaminopropyl methacrylate.

Also suitable as monomers of group (b) are monomers containing sulfo groups, such as, for example, vinylsulfonic acid, allylsulfonic acid, meth allylsulfonic acid, styrene sulfonic acid, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate and acrylamidomethylpropanesulfonic acid, and monomers containing phosphonic acid groups, such as vinylphosphonic acid, allyl and acrylamidomethyl propanephosphonic acid. This group of monomers also includes N-vinylpyrrolidone, N-vinyl caprolactam, N-vinylformamide, N-vinyl-N-methylformamide, 1-vinylimidazole, 1-vinyl-2-methylimidazole, vinyl acetate and vinyl propionate. Also suitable as monomers of group (b) are the esters of alkoxylated C ₁ to C ₁₈ alcohols which have been reacted with 2 to 50 mol of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, with the monoethylenically unsaturated carboxylic acids of group (a ), e.g. B. the esters of acrylic acid, methacrylic acid or maleic acid with a C ₁₃ / C ₁₅ oxo alcohol which has been reacted with different amounts of ethylene oxide, for. B. 3 moles, 5 moles, 7 moles, 10 moles or 30 moles of ethylene oxide.

Both the mono- and the come from the esters of dicarboxylic acids Diester into consideration. The basic monomers were preferably in the form the salts with mineral acids, e.g. As hydrochloric acid, sulfuric acid or nitrate acid, or used in quaternized form (suitable quaternization medium are, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, Ethyl chloride or benzyl chloride).

Further monomers of group (b) are amides of monoethylenically unsaturated C ₃ to C ₈ carboxylic acids with amide groups of the structure

considered in the

R³, R⁴ = H, CH₃, C₂H₅,
R = C₁ to C₂₈ alkyl,
n = 2 to 100 and
R² = H, R¹

mean.

The preferred monomers of group (b) are hydroxyethyl acrylate, Hydroxypropyl acrylates, vinyl acetate, N-vinyl pyrrolidone, acrylamidomethyl propanesulfonic acid and N-vinylimidazole.

A further modification of the graft copolymers can thereby be achieved be that the graft polymerization in the presence of monomers of Group (c) carries out. In this case, the monomer mixtures contain up to to 5 wt .-% of at least two ethylenically unsaturated non-konju gated double bonds in the molecule containing monomer. This verb Solutions are usually used as crosslinkers in copolymerizations turns. You can use the monomers used for copolymerization Group (a) or the monomer mixtures from (a) and (b) can be added. in the If used, the preferred amount of monomers is  (c) 0.05 to 2% by weight. The use of the monomers of group (c) during the copolymerization causes an increase in the K values of the copoly merisate. Suitable compounds of this type are, for example, methylene bisacrylamide, esters of acrylic acid and methacrylic acid with polyvalent Alcohols, e.g. B. glycol diacrylate, glycerol triacrylate, glycol dimethacrylate, Glycerol trimethacrylate, and at least twice with acrylic acid or Methacrylic acid esterified polyols such as pentaerythritol and glucose. Ge suitable crosslinkers are also divinylbenzene, divinyldioxane, pentaery thrittriallyl ether and pentaallylsucrose. Preferably used from this group of compounds water soluble monomers such as glycol di acrylate or glycol diacrylates of polyethylene glycols of a molecular weight weights up to 3000.

The polymerization of the monomers (a) and, if appropriate, additionally (b) and (c) takes place in the presence of natural products based on poly saccharides, oligosaccharides, monosaccharides and their derivatives. The Natural products are e.g. B. saccharides of plant or animal origin or products of the metabolism of microorganisms and their degradation and Modification products that are already dispersible in water or alkalis or are soluble or during the polymerization of the monomers (a) and optionally (b) and (c) directly or in part or entirely with Alkaline, ammonia or amine neutralized form dispersible or become soluble.

These are, for example, pectin, algin, chitin, chitosan, heparin, Carrageenan, agar, gum arabic, tragacanth, karaya gum, ghatti gum, Locust bean gum, guar gum, tare gum, inulin, xanthan, dextran, Nigeran and pentosans like Xylan and Araban, whose main ingredients are from D-glucuronic acid, D-galacturonic acid, D-galacturonic acid methyl ester, D-mannu ronic acid, L-guluronic acid, D- and L-galactose, 3,6-anhydro-D-galactose, L-arabinose, L-rhamnose, D-glucuronic acid, D-xylose, L-fucose, D-mannose, D-fructose and D-glucose, 2-amino-2-deoxy-D-glucose and 2-amino-2-deoxy D-galactose and their N-acetyl derivatives exist.

From an economic point of view, poly is used Saccharide of component (B) preferred in the graft copolymerization Starch, thermally and / or mechanically treated starch, oxidative, hydro starches degraded lytically or enzymatically, oxidized hydrolytically or oxidized enzymatically degraded starches and chemically modified starches and chemically modified monosaccharides and oligosaccharides. Prince All strengths are suitable. However, starches from are preferred Corn, wheat, rice, tapioca and especially starch from potatoes. The Starches are practically insoluble in water and can be found in known ones Way by thermal and / or mechanical treatment or by a  enzymatic or acid catalyzed degradation into a water soluble Form to be transferred. Oxidative abge are also suitable as component (B) built strengths. As starch breakdown products, either by oxidative, hydrolytic or enzymatic degradation of starch are available for example, the following compounds are called: dextrins, such as white and Yellow dextrins, maltodextrins, glucose syrups, maltose syrups, hydrolysates from high content of D-glucose, saccharification products as well as maltose and D-glucose and its isomerization product fructose. As component (B) are of course also suitable for mono- and oligosaccharides, such as Galactose, mannose, ribose, sucrose, raffinose, lactose and trehalose as well as cellulose degradation products, for example cellubiosis and its Oligomers.

As component (B) come oxidized starches, such as. B. dialdehyde starch and oxidized starch degradation products, such as Gluconic acid, glucaric acid and glucuronic acid. Such connections will be for example by oxidizing starch with periodate, chromic acid, Hydrogen peroxide, nitrogen dioxide, nitrogen tetroxide, nitric acid or get hypochlorite.

Chemically modified polysaccha are also suitable as component (B) ride, especially chemically modified starches, e.g. B. with acids Starches and starches converted to ethers with alcohols and starch degradation Products. The esterification of these substances is both with inorganic also possible with organic acids, their anhydrides or chlorides. At The esterified water leads to an acid catalysis by direct esterification based cleavage of glycosidic bonds. Of special technical Interest are phosphated and acetylated starches and starch degradation Products. The most common method of etherifying starch is treatment Starch and starch degradation products with organic halogen compound solutions, epoxides or sulfates in aqueous alkaline solution. Starch ether are, for example, the alkyl ethers, hydroxyalkyl ethers, carboxyalkyl ethers and allyl ether of starch. Among chemically modified starches according to Component (B) should also be understood as cationically modified starches be, e.g. B. with 2,3-Epoxipropyltrimethylammoniumchlorid implemented Strengths such as B. are described in US-PS 36 49 616.

Chemically modified polysaccharides also include, for example Carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, Carboxymethylhydroxyethyl cellulose, sulfoethyl cellulose, carboxymethyl sulfoethyl cellulose, hydroxypropyl sulfoethyl cellulose, hydroxyethyl sulfo ethyl cellulose, methylsulfoethyl cellulose and ethyl sulfoethyl cellulose.  

Chemically modified degraded ones are also suitable as component (B) Starches, for example hydrogenation products from starch hydrolysates, such as Sorbitol and mannitol, maltitol and hydrogenated glucose syrups or oxidized hydrolytically degraded or oxidized enzymatically degraded starches.

The acid-catalyzed or enzyma products are also suitable table glycosidation or glycosidation, such as. B. methyl glucoside.

To prepare the graft copolymers, the monomers (a) and optionally (b) and / or (c) in the presence of compounds of the compo nente (B) polymerized by radicals. In some cases it can be for the Effect of the resulting graft polymer be favorable, two or use several of the compounds specified under (B), e.g. B. Mixing acid catalytically or enzymatically degraded starches and glucon acid, mixtures of a monosaccharide and an oligosaccharide, Mixtures of an enzymatically degraded starch and a monosaccharide or mixtures of glucose and sucrose or mannose. The Polymerisa tion can be in the presence or absence of inert solvents or inert diluents. Because the polymerization in the absence of inert solvents or diluents mostly too un leads uniform graft polymers, the graft polymerization is in an inert solvent or diluent is preferred. Are suitable for for example, such inert diluents in which the under (B) given compounds can be suspended and the monomers (A) to solve. In these cases, the graft polymers follow the Polymerisa tion in suspended form and can easily be filtered in solid form can be isolated. Suitable inert diluents are available from for example toluene, xylene, o-, m-, p-xylene and isomer mixtures, ethyl benzene, aliphatic hydrocarbons, such as pentane, hexane, heptane, octane, Nonane, dodecane, cyclohexane, cyclooctane, methylcyclohexane and mixtures of the named hydrocarbons or gasoline fractions that do not contain poly contain merizable monomers. Chlorinated hydrocarbons are also suitable substances such as chloroform, carbon tetrachloride, hexachloroethane, dichloroethane and tetrachloroethane. In the procedure described above, in which the Suspend compounds of component (B) in an inert diluent dated, preferably water-free compounds of the compo nente (B) and preferably used from the group of monomers (a) the anhydrides. A preferred way of producing the graft polymers is solution polymerization, the compounds of component (B), the monomers (A) and the graft copolymer formed are at least dispersed greed, preferably in dissolved form. For the solution polymer tion, for example, inert solvents such as methanol, ethanol, Isopropanol, n-propanol, n-butanol, sec-butanol, tetrahydrofuran, dioxane, and mixtures of the inert solvents mentioned. The copolymerization  can be carried out continuously or discontinuously. The compo As already mentioned above, nents (A) and (B) can also be absent be copolymerized by inert diluents or solvents. Therefor Continuous polymerization at Tempera is particularly suitable doors from 160 to 250 ° C. If necessary, it is possible in Ab presence of polymerization initiators to work. Preferably sets However, one also uses catalysts which are among the poly merization conditions form radicals, e.g. B. inorganic and organic Peroxides, persulfates, azo compounds and so-called redox catalysts.

The graft polymers are generally with the use of radical initiators produced.

As radical initiators, all those are preferred suitable at the chosen polymerization temperature have a half-life of less than 3 hours. If you do that Polymerization starts first at a lower temperature and at a higher one Temperature ends, so it is useful to add at least two different temperature decay initiators to work, namely first an initiator that disintegrates at a lower temperature to use for the start of the polymerization and then the main polymers to end with an initiator, which at a higher temperature disintegrates. You can water-soluble and water-insoluble initiators or Mixtures of water-soluble and water-insoluble initiators put. The water-insoluble initiators are then organic Phase soluble. For the temperature ranges specified below one can use, for example, the initiators listed for this.

Temperature: 40 to 60 ° C:

Acetylcyclohexanesulfonyl peroxide, diacetyl peroxidicarbonate, dicyclohexyl peroxidicarbonate, di-2-ethylhexyl peroxidicarbonate, tert-butyl perneodeca noate, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2- methyl-N-phenylpropionamidine) dihydrochloride, 2,2'-azobis- (2-methylpropione amidine) dihydrochloride.

Temperature: 60 to 80 ° C:

tert-butyl perpivalate, dioctanoyl peroxide, dilauroyl peroxide, 2,2'-azobis (2,4-dimethylvaleronitrile).

Temperature: 80 to 100 ° C:

Dibenzoyl peroxide, tert-butyl per-2-ethylhexanoate, tert-butyl permaleinate, 2,2'-azobis (isobutyronitrile), dimethyl-2,2'-azobisisobutyrate, sodium persulfate, potassium persulfate, ammonium persulfate.  

Temperature: 100 to 120 ° C:

Bis (tert-butyl peroxide) cyclohexane, tert-butyl peroxy isopropyl carbonate, tert-butyl peracetate, hydrogen peroxide.

Temperature: 120 to 140 ° C:

2,2-bis (tert-butylperoxy) butane, dicumyl peroxide, di-tert-amyl peroxide, Di-tert-butyl peroxide.

Temperature: <140 ° C

p-methane hydroperoxide, pinane hydroperoxide, cumene hydroperoxide and tert.- Butyl hydroperoxide.

In addition to the initiators mentioned, salts or are also used Complexes of heavy metals, e.g. B. copper, cobalt, manganese, iron, Vanadium, cerium, nickel and chromium salts or organic compounds, such as Benzoin, dimethylaniline or ascorbic acid, so can the half-lives of the radical initiators indicated are reduced. So can for example, tert-butyl hydroperoxide with the addition of 5 ppm Activate copper-II-acetylacetonate in such a way that already at 100 ° C can be polymerized. The reducing component of redox catalysis For example, compounds such as sodium sulfite, Sodium bisulfite, sodium formaldehyde sulfoxylate and hydrazine are formed will. Based on the monomers used in the polymerization 0.01 to 20, preferably 0.05 to 10 wt .-% of a poly is used polymerization initiator or a mixture of several polymerization initiators. The redox components used are 0.01 to 5% of the reducing acting connections to. Heavy metals range from 0.1 to 100 ppm, preferably 0.5 to 10 ppm used. It is often an advantage a combination of peroxide, reducing agent and heavy metal as Use redox catalyst.

The polymerization of the monomers (a) and, where appropriate, to be used ending monomers (b) and / or (c) can also by the action of ultra violet radiation, optionally in the presence of UV initiators, be performed. For polymerizing under the influence of UV rays are used for the photo that is usually considered for this initiators or sensitizers. This is for example as to compounds such as benzoin and benzoin ether, α-methylbenzoin or α-phenylbenzoin. So-called triplet sensitizers, such as benzyl diketal, can be used. Serve as UV radiation sources for example, next to high-energy UV lamps, such as carbon arc lamps, mercury Silver vapor lamps or xenon lamps also have low-UV light sources, such as lights fabric tubes with a high proportion of blue.  

In order to produce polymers with a low K value, the graft poly merization conveniently carried out in the presence of regulators. Appropriate Examples of regulators are mercapto compounds, such as mercaptoethanol, Mercaptopropanol, mercaptobutanol, mercaptoacetic acid, mercaptopropion acid, butyl mercaptan and dodecyl mercaptan. The following are also suitable as controllers the allyl compounds, such as allyl alcohol, aldehydes, such as formaldehyde, acet aldehyde, propionaldehyde, n-butyraldehyde and isobutyraldehyde, formic acid, Ammonium formate, propionic acid, hydrazine sulfate and butenols. if the Polymerization in the presence of regulators is required thereof 0.05 to 20 wt .-%, based on those used in the polymerization set monomers.

In order to produce colorless or only slightly colored graft polymers from components (A) and (B), the polymerization is carried out in the presence of water-soluble phosphorus compounds in which the phosphorus has an oxidation number of 1 to 4, the water-soluble alkali metal or ammonium salts of which are water-soluble -PO (OH) ₂ group-containing compounds and / or their water-soluble salts. Phosphorous acid is preferably used. The phosphorus compounds in question are used to reduce the discoloration of the graft copolymers in amounts of from 0.01 to 5% by weight, based on the monomers (A) used. The phosphorus compounds in question are described in EP-A-01 75 317.

The copolymerization of components (A) and (B) is usually carried out in one in an inert gas atmosphere with the exclusion of atmospheric oxygen. While the polymerization is generally used for thorough mixing of the Reaction participants worried. For smaller approaches where one safe dissipation of the heat of polymerization is guaranteed, you can Reactants, preferably in an inert dilution medium, copolymerize discontinuously by reacting the Reak tion mixture heated to the polymerization temperature. These temperatures are in the range from 40 to 150 ° C. With this method you get but graft copolymers, which when using dicarboxylic acids have relatively high content of unpolymerized dicarboxylic acid. Around to be able to better control the course of the polymerization reaction, therefore, the monomers (A) are added after the polymerization has started the polymerizing mixture continuously or batchwise to the extent to that the graft polymerization is good in the desired temperature range is controllable. A type of addition of the monomers is preferred Component (A) in which the verbin is first in the polymerization reactor Component (B) or at least some of the compounds of Component (B) together with at least one monomer from group (a) in Submitted reactor and therein with stirring to the desired polymer  tion temperature heated. As soon as this temperature is reached you add for this over a period of about 1 to 10, preferably 2 to 8 hours, optionally the remaining monomers of group (a) and given if the monomers (b) and optionally (c) and the initiator and if necessary, a controller. Such an approach is used at for example when polymerizing components (A) and (B) in one inert diluent in which component (B) is suspended and also used in the graft copolymerization carried out in solution.

The graft copolymers are preferably by suspension or Solution polymerization of components (A) and (B) in an aqueous medium provided, the solution polymerization in water is particularly preferred is. In solution polymerization in an aqueous medium, for example demonstrate that the monomers (a) and at least part of Ver Compounds of component (B) in an aqueous medium and optionally the remaining monomers of group (a) and optionally the monomers ren (b) and optionally the monomers (c) continuously or batch as the polymerizing reaction mixture adds and co polymerizes that the degree of neutralization of the copolymerized monomer Units (1) and (2) of the monomers of group (a) after completion of the Graft copolymerization, d. H. if at least 95, preferably 98-99% of the Monomers are polymerized, is 20 to 80%. Preferably the Monomers (1) of group (a) already at the start of the polymerization at least 20% neutralized form used. At the graft copoly merization in an aqueous medium, the total amount of compounds component (B) or only a part, e.g. B. 50% of the compounds of the Submit component (B) together with the monomers (1) of group (a) and the remaining amounts of compounds of component (B) the polymeri reaction mixture together with the monomers (2) of group (a) and optionally the monomers (b) and / or (c) continuously or add in batches. To graft copolymers with a low residual content unpolymerized monomer (1) of group (a), d. H. in particular To obtain maleic acid, it is important to maintain the degree of neutralization of the monomers controlled during the copolymerization. He is said to be during the graft copolymerization is 20 to 80, preferably 30 to 70%. For example, monomers (1) and (2) of group (a) partially neutralize, so that their degree of neutralization in each case specified range. But it is also possible to pre-in the reactor added monomers (1) of group (a) completely or to about 90% neutralize and the monomers (2) of group (a) in non-neutra lized form so that the total degree of neutralization of Monomers (1) and (2) of group (a) and optionally (b), d. H. if as (b) uses a monomer containing acid groups, e.g. B. Acrylamido methylpropanesulfonic acid or vinylphosphonic acid, during the poly  merization of initially approx. 100% or approx. 90% to values in the range decreased from 20 to 80%. To a certain degree of neutralization within half this range of monomers (1) and (2) of group (a) obtained, a base, for. B. Soda add lye, potassium hydroxide solution, ammonia or ethanolamine. In dependence of the composition of the graft copolymers is the main amount, i. H. 60 up to 80% of the monomers (1) and (2) of group (a) in a neutralisa degree of polymerisation from 20 to 80%. The Lö is particularly preferred solution copolymerization with hydrogen peroxide, sodium persulfate or Mi in any ratio as initiator. Here for 0.5 to 20% by weight, based on the monomers (A), is required Initiator. Are the monomer mixtures (A) composed of a small proportion of the Monomers (1) of group (a) will have a relatively low amount of initiator and with a high proportion of the monomers (1) of group (a) a larger one Initiator amount used, for. B. at 90 wt .-% monomer (1) of group (a) about 15 to 18 weight percent initiator. Here too, one proceeds in such a way that one at least part of component (B) together with the monomers (1) the group (a), which preferably neutralizes approximately at least 90% are submitted and the monomers (2) of group (a) and optionally the monomers (b) and / or (c) while maintaining the required neutral degrees of 20 to 80% admits. The degree of neutralization of the mono mer (2) of group (a) can either correspond by separate addition the amounts of base or by adding partially neutralized mono mer (2) of group (a) to the reaction mixture. The neutralisa Degree of tion of the partially neutralized monomers (2) of group (a) then in the range of 20 to 80%.

As already mentioned, polysaccharides in aqueous suspension can Graft copolymerization are subjected. Preferably, however, one poses Graft copolymers from polysaccharides in that a water insoluble polysaccharide first in aqueous suspension with the addition of Enzymes and / or acids are converted into a water-soluble form and there when the aqueous solution of the degraded polysaccharide is available from Propfco subject to polymerization. This first becomes water-insoluble Polysaccharide, such as potato starch, suspended in water and dismantled. This degradation can take place under the influence of enzymes, e.g. B. α- or β-amylase or debranching enzymes, such as. B. pullulanase, or by exposure to inorganic or organic acids ter way. Suitable as inorganic acids for example phosphoric acid, sulfuric acid, hydrochloric acid and nitric acid. Suitable organic acids are, for example, saturated or unsung saturated carboxylic acids, e.g. B. formic acid, acetic acid, propionic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, p-toluenesulfonic acid and Benzenesulfonic acid. Converting the polysaccharides into one water soluble  Liche form is preferably carried out with a monomer (a) which finally used in graft copolymerization. So you can at for example, in a simple manner, potato starch or corn starch in aqueous Suspension by adding acrylic acid, methacrylic acid, maleic acid or Itaconic acid in the temperature range from 50 to 150 ° C hydrolytically dismantle. As soon as the starch has reached the desired degree of degradation, the added monocarboxylic acid or maleic acid or itaconic acid at least 20, preferably 90%, neutralized and by adding the remaining monomers of group (a) and optionally of monomers (b) and optionally (c) the graft copolymerization is carried out.

The enzymatic breakdown of starch is in the temperature range from 30 to 120 ° C performed while the hydrolytic degradation of the starch Temperatures from 50 to 150 ° C. For hydrolytic degradation one needs about 5 minutes to 10 hours, the degree of hydroly table degradation of starch from the selected temperature, pH and depends on the time. More information on the breakdown of starch can Specialist literature can be found, cf. e.g. B. Günther Tegge, strength and Starch derivatives, Behr′s Verlag, Hamburg 1984. In some cases it has proven to be advantageous already in the enzymatic or hydrolyti degradation of the starch to include at least one of the phosphorus compounds set which lead to polymers according to the teaching of EP-A-01 75 317, that are not or only very little colored.

In graft copolymerization, the temperatures are usually in the Range from 40 to 180, preferably 60 to 150 ° C. As soon as the temperature in the copolymerization above the boiling points of the inert diluent or solvent or the monomers, the copolymerization is under Printing done. The concentration of components (A) and (B) is in the copolymerization in the presence of inert solvents or inert ver fertilizers 10 to 80, preferably 20 to 70 wt .-%. The production the graft copolymers can in the usual polymerization respectively. This is done, for example, by using a stirred kettle with a Anchor, blade, impeller or multi-stage impulse counterflow stirrers out are equipped. Especially in the absence of graft copolymerization of diluents, it can be advantageous to graft copolymerize in kneaders. Likewise, it may be necessary to use a kneader to polymerize when working at high concentrations or when the natural products are high molecular weight and initially swell strongly.

This gives water-soluble graft copolymers with K values from 8 to 70, preferably 10 to 40, (measured on 1% aqueous solutions of the Copolymers at pH 7 and 25 ° C). The following the procedures given above Graft copolymers that can be produced are colorless to brownish in color  Products. When polymerizing, they are dispersed in an aqueous medium ions or polymer solutions. Depending on the particular Zu composition and the concentration of the graft copolymers are low-viscosity to pasty aqueous solutions or dispersers sions. The graft polymers described above are by nature proportion of the material compared to the previously used copolymers based ethylenically unsaturated monomers are better biodegradable, at least however, can be eliminated from the wastewater of sewage treatment plants with the sewage sludge.

The aqueous copolymer solutions thus obtainable can be used directly as Water treatment agent to reduce scale deposition and water hardness excretion can be used in water-bearing systems. It is possible to combine the polymers according to the invention with others Dispersants such as phosphonates, phosphonoalkane carboxylic acids etc.

The mode of action of the graft polymers as a so-called the water treatment consists in the formation of crystals of the Hardness forming salts, such as calcium carbonate, magnesium oxide, magnesium carbonate, Calcium, barium or strontium sulfate, calcium phosphate (apatite) and prevent similar in the substoichiometric dosage range or to influence the formation of these precipitates so that no hard and stone-like deposits arise, but are easily washed out in the water finely divided excretions are formed. In this way, the Surfaces of e.g. B. heat exchangers, pipes or pump components from Keep coverings free and reduce their tendency to corrode. In particular the risk of pitting corrosion under these coverings is reduced. Furthermore, the growth of microorganisms on this metal surface areas difficult. Due to the influence of the deposit inhibitors, the Lifespan of such systems increases and downtimes for cleaning of plant parts can be significantly reduced. The quantities required for this of scale inhibitors are 0.1 to 100, preferably 0.5 to 25 ppm, based on the respective amount of water. With water-bearing systems is it z. B. to open or closed cooling circuits, at for example of power plants or chemical plants, such as reactors, Distillation apparatus and similar components where heat is removed must be led. The use of these deposit preventers can also in Boiler water and steam generators, preferably in the water area temperatures below 150 ° C. A preferred application of the Depletion inhibitor to be used according to the invention is also desalination extraction of sea and brackish water by distillation or membrane processes, such as B. reverse osmosis or electrodialysis. So z. B. in the so-called MSF distillation process (multistage flash evaporation) for sea water Desalination of thickened sea water with increased temperature in circulation drive. The deposit inhibitors effectively prevent the excretion of hardness agents such as B. brucite and their caking on plant components.  

In membrane processes, the membranes can be damaged by crystallization hardening agents can be effectively prevented. This way these anti-fouling agents improved higher thickening factors Yield of pure water and longer life of the membranes. Another Application of the deposit inhibitor is e.g. B. when evaporating sugar juices from cane or beet sugar. In contrast to the one described above Applications are here the sugar thin juice for cleaning z. B. Calcium hydroxide, carbon dioxide, sulfur dioxide or optionally phosphoric acid added. After filtering in sugar juice remaining poorly soluble Calcium salts such as As calcium carbonate, sulfate or phosphate fall then during the evaporation process and can be used as rock hard coverings occur on heat exchanger surfaces. This also applies to sugar accompanying substances, such as silica or calcium salts of organic acids, such as e.g. B. oxalic acid.

The same applies to processes that follow sugar extraction, so z. B. the production of alcohol from residues from sugar production.

The copolymers which can be used according to the invention as scale inhibitors are able to largely prevent the above-mentioned formation of deposits, so that downtime of the systems for cleaning, for. B. by boiling, can be significantly reduced. An essential point of view here is also the considerable energy savings through avoidance of the heat-insulating coverings mentioned.

The amounts of the deposit inhibitor required in the applications described are different, but are between 0.1 and 100 ppm, based on cooling water, boiler water, process water or z. B. Sugar juice.

The products to be used according to the invention have a better dispersion alloy against hardness forming salts such as Ca carbonate, Ca sulfate and Ca Phosphate and are also more compatible with Ca ions than homopoly merisate of acrylic acid.

The K values of the copolymers were determined according to H. Fikentscher, Cellulose chemistry, volume 13, 48 to 64 and 71 to 74 (1932) in aqueous solution a pH of 7, a temperature of 25 ° C and a polymer concentration tion of the sodium salt of the copolymer of 1 wt .-% determined. The Percentages relate to the weight of the fabrics.

Examples Production of the graft polymers Graft polymer 1

In a heatable reactor equipped with a stirrer, reflux condenser, thermometer, Provide inlet devices, nitrogen inlet and outlet devices is, 309.4 g of the 80.7% solution of a two-step enzyme conversion obtained starch saccharification product with a combination setting of approx. 10% dextrose, approx. 11% maltose, approx. 14% maltotriose and 65% higher sugar, 354.6 g water and 1.8 g phosphorous acid in weak nitrogen flow heated to 95 ° C and within 4 hours metered in in parallel, 294.6 g of acrylic acid, 35.35 g of 2-mercaptoethanol dissolved dissolved in 50 g water and 2.94 g sodium persulfate in 70 g water. On finally it is cooled to 80 ° C. and a solution at 80 ° within 1 hour solution of 0.3 g of 2,2'-azobis- (2-methylpropionamidine) dihydrochloride in 30 g Water metered in evenly. Then at 80 ° C with 296 g 50% sodium hydroxide solution neutralized. Then one after the other a solution of 0.9 g sodium disulfite in 15 g water and 9.8 g 30% hydrogen Peroxide added and reheated at 80 ° C for 1 hour. The received yellowish polymer solution has a solids content of 46.8% and has a pH of 7.0. The K value of the graft polymer is 14.6.

Graft polymer 2

In a heatable reactor equipped with a stirrer, thermometer, feed device lines, and a distillation device, 1056 g a mixture of isopropanol and water in a ratio of 75:25, 806.46 g Maltodextrin with a DE value (according to Luff-Schoorl) of 11 to 14, 94% and 47.16 g of 30% hydrogen peroxide. Then the Pressed reactor with 3 bar nitrogen 3 times and relaxed again and then heated to 120 ° C, with a pressure of 3 bar. Now, at 120 ° C, 1137 g of acrylic acid become uniform within 6 hours dissolved in 966 g of a mixture of isopropanol and water in the ratio 75:25, and within 8 hours, 80 g of 30% hydrogen peroxide dissolved in 304 g of a mixture of isopropanol and water in a ratio of 75:25, added. The mixture is then reheated at 120 ° C. for a further 2 hours. Then it will be cooled to 100 °, relaxed and by introducing water vapor Isopropanol is distilled off until a boiling point of 100 ° is reached. Subsequently, by adding 882 g of 50% aqueous sodium hydroxide solution neutralized to a pH of 8. Now it is cooled and the 54.6% Almost clear solution adjusted to 45% by dilution with water. The K value of the graft polymer is 19.5.  

Graft polymer 3

is made according to the formulation of graft polymer 2 with the exception that that the acrylic acid solution in 3 hours and the hydrogen peroxide evenly metered in within 4 hours. The K value of the obtained Graft polymer is 21.7 g.

Graft polymer 4

In the reactor in which the graft polymer 1 was produced, 290 g Maltodextrin with a DE value (according to Luff-Schoorl) of 11 to 14, 94%, 470 g water, 101.4 g maleic anhydride, 4.2 ml of a 0.1% solution of iron (II) ammonium sulfate in water and 74.5 g of sodium hydroxide at the boil heated. A mixture of 120 g of acrylic is added within 5 hours acid and 114.4 g 58% aqueous solution of the sodium salt of acrylamido methylpropanesulfonic acid and 80 g of hydrogen peroxide within 6 hours 30% and the same solution of 24 g sodium persulfate in 72 g water moderately under boiling conditions. Then the reaction mixture is still Boiled at reflux for 2 hours and then with cooling with 155 g of 50% neutralized aqueous sodium hydroxide solution. The brown, clear solution obtained has a solids content of 42.3% and a pH of 7.0. The K value of the Graft polymer is 27.6.

Graft polymer 5

In the reactor in which the graft polymer 1 was produced 127.2 g maltodextrin with a DE value (according to Luff-Schoorl) from 11 to 14, 370 g of water, 3.8 g of phosphorous acid in a weak stream of nitrogen Heated to 95 ° C. and a mixture of 407 g in parallel within 4 hours Acrylic acid, 35 g water and 101.8 g N-vinylimidazole and a mixture of 25.44 g of 2-mercaptoethanol and 78.5 g of water and a solution of 3.2 g sodium persulfate in 75 g water and a solution of 3.2 g 2,2'-azo bis- (2-methylpropionamidine) dihydrochloride in 65 g of water evenly 95 ° C metered. The mixture is then reheated for a further 2 hours and then reduced to 40 ° C. cools and neutralized with 378 g of 50% aqueous sodium hydroxide solution. The yellow Liche solution has a solids content of 45.8% and a pH of 7.1. The K value of the graft polymer is 26.9.

Graft polymer 6

235.4 g of maltodextrin are added to the reactor described in Example 1 a DE value of 11 to 14, 230 g of water, 117.54 g of maleic anhydride and 173 g of 50% aqueous sodium hydroxide solution and heated to boiling. The degree of neutralization of the resulting maleic acid is 90.1%.  

Immediately after the start of boiling, a solution is added within 5 hours from 139.2 g of 97% acrylic acid and 300 g of water and within 6 hours the separate solutions of 3.2 g of sodium persulfate in 80 g Water and 10.14 g of 30% water peroxide in 60 g of water evenly and polymerizes at the boiling point of the reaction mixture. The one in the graft co Maleic acid and acrylic acid units contained in the polymer have one Degree of neutralization of 50.6%. After finishing hydrogen per oxide addition, the reaction mixture is heated to boiling for a further 1 hour and neutralized by adding 137 g of 50% aqueous sodium hydroxide solution. Man receives a clear, viscous, brown solution with a solids content of 39%. The graft copolymer has a K value of 31.5.

Graft polymer 7

In a heatable reactor equipped with a stirrer, thermometer, feed device lines, and a distillation device, 1056 g a mixture of isopropanol and water in a ratio of 75:25, 806.46 g Maltodextrin with a DE value (according to Luff-Schoorl) of 11 to 14, 94% and 47.16 g of 30% hydrogen peroxide. Then the Pressed reactor with 3 bar nitrogen 3 times and relaxed again and then heated to 120 ° C, with a pressure of 3 bar. Now, at 120 ° C, 682.2 g of acrylic acid, 227.4 g of N-vinylimidazole and 227.4 g of acrylamidomethylpropanesulfonic acid dissolved in 966 g of a mixture of isopropanol and water in the ratio 75:25, and within 8 hours, 80 g of 30% hydrogen peroxide dissolved in 304 g of a mixture of isopropanol and water in a ratio of 75:25, added. The mixture is then reheated at 120 ° C. for a further 2 hours. Then it will be cooled to 100 °, relaxed and by introducing water vapor Isopropanol is distilled off until a boiling point of 100 ° is reached. Then by adding 50% aqueous sodium hydroxide solution up to neutralized to a pH of 8. Now it is cooled and the 50.6% Almost clear solution adjusted to 45% by dilution with water. The K value of the graft polymer is 23.5.

Water treatment agent 1

Commercial homopolymer of acrylic acid with a K value of 15.

Water treatment agent 2

Commercial homopolymer of acrylic acid with a K value of 20.  

Water treatment agent 3

Commercial homopolymer of acrylic acid with a K value of 25.

The graft polymers described above are based on their suitability as Water treatment agent subjected to the following tests and with commercially available water treatment agents compared.

Examples according to the invention and comparative examples CaSO ₄ test

500 ml of a saturated CaSO ₄ solution is evaporated to 200 g at 200 ° C. in a drying cabinet. The mixture is left to stand overnight and filtered the next day through a membrane filter (0.45 µm).

50 ml of the filtrate is titrated with an aqueous 0.2 M solution of Na ₂ H ₂ EDTA (EDTA = ethylenediaminetetraacetic acid) and the Ca fraction which is still dissolved is determined. The inhibition when adding 1 ppm polymer is calculated against a blank test without addition of polymer.

CaCO ₃ test

An aqueous test solution is prepared from components A and B.

• A: 3.36 g NaHCO₃ / l
• B: 1.58 g CaCl₂.2 H₂O / l, 0.88 g MgSO₄ / l

100 ml each of the above solutions A and B are pipetted into a 250 ml bottle, mixed with 5 ppm graft polymer, sealed and stored at 86 ° C. for 16 hours. After cooling to room temperature and filtration, the solution is titrated with a 0.2 M solution of Na ₂ H ₂ EDTA.

Ca ₃ (PO ₄ ) ₂ test

100 ml of a solution with the following concentrations are prepared:

1.095 g / l CaCl₂ · 6 H₂O
0.019 g / l NaHPO₄ · 2 H₂O
2 ppm polymer.

The pH is adjusted to 8.6 with a borax buffer. The solution is then stirred for 3 hours at 70 ° C. and left to stand for 24 hours. To At this time, the light transmission (LD, whitish) with a photo meters measured. The photometer is opened beforehand with distilled water 100% LD set.

The data on polymer refer to 100% substance.

The test results are given in the table.

As can be seen from the table, the graft polymers in Comparison to the homopolymers of acrylic acid with a comparable K value an improved effectiveness.

Claims (4)

1. Use of water-soluble graft polymers of monosaccharides, oligosaccharides, polysaccharides and their derivatives, which are obtainable by free-radically initiated polymerization of

• A) Monomer mixtures
  • a) 40 to 100% by weight of monoethylenically unsaturated C ₃ to C ₁₀ monocarboxylic acids and / or monoethylenically unsaturated C ₄ to C ₈ dicarboxylic acids, their anhydrides, alkali metal salts and / or ammonium salts,
  • b) 0 to 60 wt .-% of other monoethylenically unsaturated monomers which are copolymerizable with the monomers (a), and
  • c) 0 to 5 wt .-% at least 2 ethylenically unsaturated, non-conjugated double bonds in the molecule having monomers

in the presence of

• B) monosaccharides, oligosaccharides, polysaccharides, oxidatively, hydrolytically or enzymatically degraded polysaccharides, oxidized hydrolytically or oxidized enzymatically degraded polysaccharides, chemically modified mono-, oligo- and polysaccharides or mixtures of the compounds mentioned in the weight ratio (A): (B) of ( 95 to 20): (5 to 80) as water treatment agent.

2. Use according to claim 1, characterized in that as component (A)

• a) acrylic acid, methacrylic acid, maleic acid or mixtures thereof and
• b) uses acrylamidomethylpropanesulfonic acid or N-vinylimidazole or mixtures thereof.

3. Use according to claim 1 or 2, characterized in that as Component (B) Starch saccharification products or hydrogenated starch uses hydrolysates.