WO2009121947A1

WO2009121947A1 - Acidic polymer composition and process for its production

Info

Publication number: WO2009121947A1
Application number: PCT/EP2009/053982
Authority: WO
Inventors: Frank Dietsche; Bolette Urtel; Christian Hubert Weidl
Original assignee: Basf Se
Priority date: 2008-04-04
Filing date: 2009-04-03
Publication date: 2009-10-08

Abstract

A polymer composition comprising the following components: from 10 to 70% by weight of a solvent (S), from 30 to 70% by weight of an acidic polymer component (B), from 1 to 7000 ppm of an alkyne alkoxylate (A), of the general formula (I) HC=C-CH2-O(-CH2-CHR1-O-)nH (I), where the moiety R1 is H or methyl and n is from 1 to 10, and, if appropriate, further additives is stable in storage even over a prolonged period and can be stored in conventional vessels used for transport and storage.

Description

Acid polymer compositions and process for their preparation

description

The present invention relates to an acidic polymer composition, a process for the preparation of this polymer composition, and the use of specific alkyne alkoxylates as a corrosion inhibiting component for this polymer composition.

For decades, different acidic polymers, such as. As polyacrylic acids or polymethacrylic acids and methods for their preparation. Acid polymers find z. B. Use in the manufacture of building aids (such as glass fiber mats, concrete and cement additives), dispersants z. As for pigments or in formulations to prevent deposits, for example in water tanks, dishwashers and similar devices.

In many known processes for the preparation of acidic polymers, the problem has arisen that they compared to metals, due to the low pH of the starting materials (eg., Acrylic acid), but also the acidic polymers or other auxiliary agents used such. B. radical generator (starter, molecular weight regulator), corrosive action. This is done depending on the concentrations, temperatures, time and also the halide content. The surfaces of the equipment used in the production (such as reactors, boilers, pipes, storage tanks) are continuously affected and possibly completely unusable.

The transport of acidic polymers and storage z. B. in storage vessels proves to be problematic because it comes to different forms of corrosion. In particular, repeated use of boilers or storage and transport containers, the material of the equipment is brittle and leaking Discolour metal ions, reduce the wall thicknesses by surface corrosion and / or the equipment gets a rough surface.

In the known methods for effectively combating corrosion, passivating agents, such as, for example, phosphates, phosphonates or other heavy metal-containing auxiliaries, have hitherto been added to the acidic polymer solutions, resulting in considerable stress on the persons working with the concentrates and on the environment (eg eutrophication). can lead. An alternative to avoiding transport and storage corrosion in acidic polyacrylic acids and other acidic polymers or copolymers is to carry out a (simultaneous) neutralization step directly in connection with the preparation and / or dilute the polymers so strongly that the aggressive corrosive properties reduce to a tolerated limit or disappear completely. However, these options are often neither economically nor ecologically advantageous because high water and Salzfrachtanteile greatly reduce the polymeric drug content and can greatly degrade the overall properties of the products in their subsequent use.

In the preparation of the polyacrylates themselves arise by the acidic reaction conditions (usually pH values of 0 to 4) in combination with high reaction temperatures (for example, higher than 60 ° C) increased problems of different types of corrosion, which in the known methods by the Addition of z. As corrosion inhibitors or co-monomers or by a general conversion of the polymerization in an organic solvent can be reduced. However, the use of organic solvents leads to a considerable disadvantage in terms of time and equipment-related overhead, which causes cost increases. It has been found that the use of certain components before or during the polymerization can be better fitted into an existing process scheme and the manufacturing costs can be reduced with small addition amounts of these components.

An object of the present invention was to find heavy metal-free, preferably water-soluble (soluble more than 5 percent), non-toxic and phosphorus-free, optionally also nitrogen-free and non-pH-modifying and non-salt-forming components which inhibit corrosion and which can be used before, during and / or after the preparation of the polyacrylic acids or acidic polymers (in particular in the pH range of <4) and ensure low removal rates and a low pitting tendency on all common types of steel (in particular stainless steel). The pH of the compounds may be e.g. B. measured according to DIN 19268)

WO 2004/074372 presents various copolymers which comprise acrylic acid or methacrylic acid monomer units, these polymers also being able to comprise various auxiliaries.

EP-A 0 583 086 describes the preparation of polymers with customary starters and / or regulators, mention being also made of polyols (ethanolamines). US Pat. No. 4,618,448 describes a process for the preparation of corrosion inhibitors in which a water-soluble polymer is used which may contain as monomer units, inter alia, unsaturated carboxylic acids or unsaturated sulfonic acids.

EP-A 0 239 770 describes corrosion-inhibiting substances which contain, for example, propargyl alcohol (3-propynol) as structural unit. From US 5,630,985 a method for water treatment to prevent deposits is further known in which a quantity of water, a polyol is added. Various water-soluble copolymers having acidic properties are further described in EP-A 1 719 784. These water-soluble copolymers consist essentially of olefinically unsaturated carboxylic acid monomers, olefinically unsaturated carboxylic acid ester monomers and olefinically unsaturated, nonionic monomers.

A process for combating corrosion in aqueous systems is also described in EP-A 0 839 932, in which process a reaction product of propargyl alcohol and ethylene oxide is used. JP-A 11264085 describes polymers containing methacrylic acid monomers which can be used as corrosion inhibitors. JP-A 2001 329386 describes copolymers based on acrylic acids which have a molecular weight of 2,000 to 15,000 and which can be used as a corrosion inhibitor. JP-A 11 310 888 describes another anticorrosive agent which is based on a copolymer with methacrylic acid building blocks.

However, despite the numerous known processes for the preparation of acidic polymers and their equipment with conventional auxiliaries, there is a need, due to the growing importance of strongly acidic polymers (low salt content) worldwide, for the known polymer compositions and processes for their preparation to be more efficient, less expensive and gentler Replace manufacturing process.

The term "acidic polymers" refers to those polymers which have a multiplicity of acidic carboxylate groups (see EP-A 0 583 086) and generally have a pH of from 0 to 4. The pH can be, for example, 10 . be determined in a 10 percent aqueous solution (according to DIN 19268).

Especially with regard to use in large scale products (eg, for concrete admixtures or dispersants), which often need to be prepared at locations remote from the preparation of the polymer composition, an acidic polymer composition is to be provided which is storage stable (preferably for a period of at least two Weeks, especially at least two months, can be stored without significant change in properties), has a high thermal capacity, can also be transported in concentrated form (preferably 30 to 70%), does not tend to discoloration due to metal salts and the surfaces of the vessels (eg made of steel or other metal alloys) does not attack. The composition should also preferably have a low viscosity already at low temperatures (eg room temperature), which allows good processability. This should be done by using low molecular weight non-volatile corrosion inhibitors.

Containers of different metallic and non-metallic materials are suitable for transporting and storing the acidic polymers.

The corrosion protection should preferably not be achieved by temporary or permanent treatment of the metallic surface, for example by application of passivation layers or other protective layers (paints).

Another problem with providing the acidic polymer compositions is the increasing demand for improved biocompatibility, reduction of phosphorus-containing additives (inorganic phosphate, phosphonates and organically bound phosphorus), and improved tolerance of the individual components to each other, for example to prevent product spoilage , A reduction in nitrogen-containing additives is desired.

Another object of the present invention is to provide a (stable) acidic polymer composition which can be provided easily and inexpensively and which does not have the above-mentioned disadvantages.

This object is achieved by providing a polymer composition containing the following components:

a) 0 to 70 wt .-%, in particular 10 to 70 wt .-%, preferably 20 to 60 wt .-% (sometimes also 0 to 50 wt .-%) of a solvent (L), in particular a polar solvent, preferably Water, b) 30 to 70 wt .-%, in particular 30 to 60 wt .-%, often 40 to 60 wt .-%, of at least one acidic polymer component (B), c) 1 to 7,000 ppm, in particular 10 to 5,000 ppm , at least one Alkinalkoxylates (A), which corresponds to the general formula (I) or (II),

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I) H (-O-CHR ¹ -CH ₂ -) _n -O-CH ₂ -C≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H, (II),

wherein the radicals R ^{1 are} each independently H or methyl and the indices n and n 'are independently from 1 to 10, d) 0 to 20 wt .-%, in particular 0 to 10 wt .-%, of one or several additives and / or auxiliaries.

The sum of all components of the polymer composition should give 100 wt .-%. In a further embodiment of the invention, the polymer composition consists of the o. Components a) to d).

A further subject of the invention is also a polymer composition which contains:

a) from 20 to 60% by weight of a polar solvent, b) from 40 to 60% by weight of at least one acidic polymer component (B), c) from 10 to 5,000 ppm of at least one alkine alkoxylate (A) corresponding to the general formula ( I) or (II),

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I)

H (-O-CHR ¹ -CH ₂ -) _n -O-CH ₂ -C≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H, (II),

wherein the radicals R ^{1 are} each independently H or methyl and the indices n and n 'independently of one another are numbers from 1 to 10, d) 0 to 10 wt .-% of one or more additives and / or auxiliaries.

The invention also provides a polymer composition which contains water as solvent (L) and as polymer component (B) at least one polymeric or copolymeric compound composed of monomers from the group of acrylic acid, methacrylic acid and maleic anhydride (or maleic acid).

The invention also provides a polymer composition which contains water as solvent (L) and as polymer component (B) at least one polymeric or copolymeric compound selected from the group consisting of polyacrylic acids and polymethacrylic acids. The invention also relates to a polymer composition containing 100 to 5,000 ppm of a Alkinalkoxylates as component A, wherein this contains 1 to 5 ethylene oxide or propylene oxide units, in particular 1 to 3 units.

The invention also provides a polymer composition which contains as solvent (L) water and additionally 0.1 to 5 wt .-% of at least one further polar solvent.

The invention also provides a polymer composition which comprises 30 to 70% by weight of polymer component (B), water as solvent (L) and 1 to 10% by weight of additives and / or auxiliaries from the group of water-soluble complexing agents, containing surface-active substances and pH regulators.

The polymer composition often contains from 30 to 70% by weight, in particular from 30 to 60% by weight, of polymer component (B), which is preferably a polyacrylic acid or a polymethacrylic acid.

The invention also provides a polymer composition comprising 45 to 55% by weight of polyacrylic acid, 45 to 55% by weight of water and 0.1 to 5% by weight of one or more additives and / or auxiliaries from the group of surface-active agents Contains substances and / or pH regulators.

The invention also relates to a process for the preparation of a polymer composition in which an acidic polymer component (B) is prepared by polymerization in the presence of an alkinalxyl acrylate (A) of the general formula (I) or (II), and if appropriate with a solvent ( L) and / or additives and / or auxiliaries.

In addition to the polymer component (B), the composition according to the invention contains at least one (water-soluble) alkoxylated alkynol (A) and optionally a solvent (L). It has been found that, surprisingly, the alkinal alkoxylates used as component (A) can be added before or during the polymerization.

These alkyne alkoxylates are not destroyed or significantly consumed in the polymerization and acidic conditions.

In addition, the composition according to the invention may also contain other components, such as further active ingredients and / or additives and / or auxiliaries.

To component A The polymer compositions according to the invention contain at least one alkoxylated alkynol (A). This component (A), which may preferably be added before or at, but optionally also after the polymerization, is explained in more detail below.

Alkyne alkoxylates have been known for years, for example from DE-A 2 241 155. They are used, inter alia, as an additive in the electrodeposition of nickel or cobalt. US Pat. No. 3,004,925 already describes the use of ethoxylated butynediol derivatives and ethoxylated propynol derivatives as corrosion inhibitors in aqueous solutions. The OH groups are each modified with - (CH ₂ -CH ₂ O) _x - groups, where x has a value of 3 to 25. Furthermore, the disclosed alkynols additionally have one or more alkyl, aryl, cycloalkyl and aralkyl groups.

The component (A) in the preparation used for the process according to the invention is preferably an amount of (based on the total composition) 1 to 7,000 ppm, in particular 10 to 6,000 ppm, often also 100 to 5,000 ppm, of at least one Alkinalkoxylates of the general formula (I) or (II),

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I) or

H (-O-CHR ¹ -CH ₂ -) _n -O-CH ₂ -C≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (II).

The indices n and n 'independently of one another are from 1 to 10.

It is known that such alkoxy groups are obtainable in particular by alkoxylation or starting from industrial polyglycols by polymer-analogous reaction or end group modification. The stated values for n thus stand for average chain lengths, the average value not having to be a natural number but also being an arbitrary rational number. It is preferable that n and n 'and a number from 1 to 8, in particular from 1 to 3.

The radicals R ¹ in (I) and (II) are each, independently of one another, preferably H or methyl. The alkyleneoxy groups may be exclusively groups derived from ethylene oxide units (EO) or groups derived exclusively from propylene oxide (PO). However, they may also be groups having both ethylene oxide units and propylene oxide units. They are preferably polyoxyethylene units. It is also possible to use mixtures of (I) and (II) and / or mixtures of different compounds (I) or various compounds. fertilize (II) can be used. Preference is given to using compounds of the formula (I).

In the polymer compositions 1 to 7,000 ppm (I) or (II) are preferably used, in particular 10 to 6,000 ppm and particularly preferably 100 to 5,000 ppm. All concentrations are based on the total polymer composition. It is also possible to first prepare and distribute a concentrate of the composition which can be chemically modified on site or diluted to the desired concentration.

The amount of (I) and / or (II) also depends on the type and amount of the polymer component (B) and the other components and on the temperature at which the polymer composition is to be processed. As a rule, the higher the temperature, the higher the concentration of component (A) should be. The compounds used (A) are in a known manner z. B. by alkoxylation of butynediol or propynol (propargyl alcohol) available, as described for example in DE-A 22 41 155.

To component L

The composition of the invention may contain a solvent (L). The component L is water or another solvent which is suitable for dissolving or dispersing, suspending or emulsifying the acidic polymer (component B). In the context of the present text, a solvent is understood as meaning a liquid matrix in which the various constituents of the composition according to the invention are dispersed as finely as possible. Such a fine distribution can be, for example in the sense of a molecularly disperse distribution, a true solution of the ingredients in the solvent. However, the term "solvent" also includes liquid matrices in which the ingredients are distributed in the sense of an emulsion or dispersion, i.e., do not form a molecular-disperse solution.

Suitable solvents (L) are, for example, water and water-miscible and water-immiscible solvents. Suitable water-miscible solvents are, for example, primary or secondary mono- or polyalcohols, for example having 1 to about 6 C atoms, such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, pentanol, hexanol, cyclohexanol or glycerol. Also suitable as water-miscible solvents are low molecular weight ketones such as acetone or methyl ethyl ketone or ether alcohols such as diethylene glycol or triethylene glycol. Also suitable in the context of the present invention are solvents (L) which are immiscible or only to a small extent miscible with water. These include, for example, ethers, such as diethyl ether, dioxane or tetrahydrofuran, aromatic solvents, such as toluene or xylene, halogenated solvents, such as dichloromethane, chloroform or tetrachloromethane, and optionally substituted aliphatic solvents, including, for example, the higher homologs of the abovementioned alcohols and ketones and paraffin hydrocarbons ,

The abovementioned solvents (L) can be used individually or as a mixture of two or more of the solvents mentioned. In the context of a preferred embodiment of the present invention, the solvent used is water, if appropriate in admixture with one or more of the abovementioned, preferably water-soluble, solvents. Especially preferred are purely aqueous compositions which contain no other solvents.

For example, if a solvent containing water and a water-immiscible solvent is used in the present invention, the solvent may contain, for example, an emulsifier to form a substantially stable W / O emulsion (Water / Oil) or O. / W emulsion to allow.

In a preferred embodiment of the invention, the composition contains from 20 to 60% by weight of water.

To the polymer component (B)

Polymer component B is an acidic polymer or copolymer, preferably composed of:

30 to 100 wt .-%, preferably 50 to 100 wt .-%, in particular 50 to 99

% By weight of acrylic acid and / or methacrylic acid, or salts thereof as component (B1),

0 to 70% by weight, preferably 0 to 50% by weight, in particular 1 to 50% by weight, of a carboxylate-containing monomer (B2) of the formula (I)

wherein the symbols have the following meanings: n is 0 to 10, preferably 0 to 5, particularly preferably 0 to 3; R ^1, R ^2, R ³ independently of one another are hydrogen, C ₁ - to C ₈ -alkyl which may be branched or unbranched, C ₃ - to C ₆ cycloalkyl, C ₂ - to C ₁₈ -

Alkenyl, which may be branched or unbranched, C ₃ - to C ₆ -cycloalkenyl, C ₆ - to C ₁₂ -aryl which may be substituted by alkyl or further aryl substituents, wherein said radicals R ¹ , R ² and / or R ^{3 may} optionally be substituted by at least one carboxyl group, or a carboxyl group; preferably R ¹ , R ² and R ^{3 are} hydrogen or C ₁ - to C ₁₈ -alkyl which is unbranched and is optionally substituted by at least one carboxyl group, or a carboxyl group; particularly preferably, one of the radicals R ¹ or R ² or R ^{3 is} a carboxyl group and the remaining radicals are hydrogen or methyl; or R ¹ , R ² and R ³ are hydrogen or methyl; R ⁴ and R ⁵ are independently hydrogen, C ₁ to C ₁₈ alkyl, which may be branched or unbranched, C ₃ to C ₆ cycloalkyl, C ₂ to C ₁₈ alkenyl, which may be branched or unbranched C ₃ - to C ₆ -cycloalkenyl, C ₆ - to C ₁₂ -aryl which may be substituted by alkyl or further aryl substituents, R ⁴ and R ⁵ are preferably hydrogen or C ₁ - to C ₁₈ -alkyl, which is unbranched, very particularly preferably hydrogen or methyl; or salts,

Anhydrides, (esters) of compounds of the formula (I), particular preference is given to maleic acid, fumaric acid, itaconic acid, crotonic acid or their salts, (esters,) anhydrides;

(wherein the formula (I) is not meant to mean acrylic acid or methacrylic acid)

and or

0 to 30 wt .-%, preferably 0 to 20 wt .-% of a further, acid-stable vinylidene comonomer (B3) which is polymerizable with the above monomers.

The polymer component (B) may also contain other comonomers (B4).

Component (B1) is acrylic acid and / or methacrylic acid or a salt of (meth) acrylic acid. It is also possible to use mixtures of the stated components as component B1. Suitable salts of (meth) acrylic acid are, in particular, the alkali metal salts or alkaline earth metal salts, preferably lithium, sodium or potassium salts. umsalze. Very particular preference is given to using, as component B1, acrylic acid and / or methacrylic acid, in particular acrylic acid, in their free acid form.

As component B2, if appropriate, a carboxylate-containing monomer of the formula (I) is used

wherein the symbols have the following meanings:

n is 0 to 10, preferably 0 to 5, particularly preferably 0 to 3

R ¹ , R ² , R ^{3 are} independently hydrogen, C ₁ - to C ₁₈ -alkyl, which may be branched or unbranched, C ₃ - to C ₆ -cycloalkyl, C ₂ - to Cia-alkenyl, which may be branched or unbranched can, C ₃ - to C ₆ -cycloalkenyl, C ₆ - to C ₁₂ -aryl which may be substituted by alkyl or further aryl substituents, said radicals R ¹ , R ² and / or R ³ optionally having at least one carboxyl group or a carboxyl group; R ¹ , R ² and R ³ are preferably hydrogen or C ₁ - to C ₁₈ -alkyl which is unbranched and is optionally substituted by at least one carboxyl group, or a carboxyl group; particularly preferably, one of the radicals R ¹ or R ² or R ^{3 is} a carboxyl group and the remaining radicals are hydrogen or methyl; or R ¹ , R ² and R ³ are hydrogen or methyl;

R ⁴ and R ⁵ are independently hydrogen, C ₁ to C ₁₈ alkyl, which may be branched or unbranched, C ₃ to C ₆ cycloalkyl, C ₂ to C ₁₈ alkenyl, which may be branched or unbranched can, C ₃ - to C ₆ - cycloalkenyl, C ₆ - C ₁₂ aryl can be up, the tuenten with alkyl or other substituted Arylsubsti-; R ⁴ and R ⁵ are preferably hydrogen or C ₁ - to C ₁₈ -alkyl which is unbranched, very particularly preferably hydrogen or methyl,

(wherein the formula (I), however, should not mean acrylate or methacrylate). It is also the salts, anhydrides, (and optionally esters) of compounds of formula (I) can be used. Preference is given to maleic acid, fumaric acid, itaconic acid, crotonic acid or their salts, (optionally esters), anhydrides, with (meth) acrylic acid or its salts (see component B1) being excluded. Preferably, the component B2 is selected from at least one compound selected from the group consisting of crotonic acid, maleic acid, fumaric acid, itaconic acid, or salts, (optionally esters) and anhydrides of said acids. Particular preference is given to using maleic anhydride or maleic acid as component B2.

Suitable salts of the abovementioned acids are in particular the alkali metal and alkaline earth metal salts. Optionally usable esters are the reaction products of said acids with C ₁ - to C ₂₀ -alcohols, preferably with C ₁ - to C ₁₆ -alcohols, particularly preferably with C ₁ to C ₁₀ -alcohols. Preference is given to using maleic acid, salts or esters of maleic acid or maleic anhydride. Preferred salts are already mentioned above. Very particular preference is given to using maleic anhydride as component (B2).

The acidic polymers (component B) may contain not only monomers (B1) and monomers (B2) but also other acid-stable, vinylidene monomers (B3). It is also possible that the polymers (component B) contain, in addition to monomers of component (B1), either monomers of component (B2) or (B3).

Suitable further components (B4) for the polymer component (B) are those comonomers which are polymerizable with the monomers mentioned under B1 and B2. Such monomers are preferably ethylenically unsaturated monomers. Suitable monomers having at least one ethylenically unsaturated group are, for example: olefins such as ethylene or propylene, vinylaromatic monomers such as styrene, divinylbenzene, 2-vinylnaphthalene and 9-vinyl-anthracene, substituted vinylaromatic monomers such as p-methylstyrene, .alpha.-methylstyrene, o-chlorostyrene, p-chlorostyrene, 2,4-dimethylstyrene, 4-vinylbiphenyl and vinyltoluene, esters of vinyl alcohol and monocarboxylic acids having 1 to 18 C atoms, such as vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl laurate and vinyl stearate, anhydrides or esters from 3 to 6 carbon atoms having α, ß-monoethylenically unsaturated mono- and dicarboxylic acids (with the exception of the compounds mentioned as component B2), in particular acrylic and methacrylic acid, with generally 1 to 20, preferably 1 to 12, particularly preferably 1 to 8 and most preferably 1 to 4 carbon atoms having alkanols such as in particular acrylic and methacrylic acid, methyl, ethyl, n-butyl, iso Butyl, tert-butyl and 2-ethylhexyl esters, dimethyl maleate or n-butyl maleate, or the esters of said carboxylic acids with alkoxy compounds, for example ethylene oxide or polyethylene oxide, such as ethylene oxide acrylate or methacrylate, the nitrile of the abovementioned α, β-monoethylenically unsaturated carboxylic acids, such as acrylonitrile and methacrylonitrile, and C ₄ . ₈ -conjugated dienes such as 1,3-butadiene and isoprene and N-vinyl compounds such as N-vinylpyrrolidone and N-vinylformamide; Vinyl ethers, H ₂ C = CH-OR ⁵ , wherein R ^{5 is} a C ₁ - to C ₁₈ -alkyl radical which may be branched or unbranched, and suitable monomers containing sulfone, sulfonate or sulfate groups. As styrene compounds come z. B. those of the general formula (II) into consideration:

in which R 'and R "independently of one another are H or C _r to C ₈ -alkyl and n is 0, 1, 2 or 3.

In a further embodiment, such polymer components B are used in the composition according to the invention which contain acid-stable, vinylidene comonomers (B3) in addition to monomers (B1). However, in a preferred embodiment, the polymer component of the polymer composition is substantially free of monomers of group (B4).

Frequently, homopolymers of acrylic acid are used as polymer component (B). In a particular embodiment, component B may also be a copolymer composed of acrylic acid and maleic anhydride (or maleic acid).

The proportion of acrylic acid is preferably 50 to 99% by weight, more preferably 50 to 80% by weight, and the proportion of maleic anhydride (or maleic acid) is just 1 to 50% by weight, particularly preferably 15 to 40% by weight. In a further preferred embodiment, component B is a copolymer composed of

(Meth) acrylic acid and maleic anhydride. For example, the copolymer is composed of 20 to 80% by weight of (meth) acrylic acid and 10 to 40% by weight of maleic anhydride.

The polymers used as component B can be prepared by various methods known to those skilled in the art.

The polymer compositions are preferably prepared by free radical copolymerization of the stated components B1 and / or B2 and / or B3 and / or B4. The proportions of the components used are varied. bar. The free radical copolymerization can be carried out, for example, in solution, emulsion, dispersion, suspension or substance.

Suitable polymerization processes for the preparation of the polymers used as component B are listed, for example, in DE-A 196 06 394. The polymers B are particularly preferably prepared by free radical copolymerization in solution. The solvent is preferably selected from the group consisting of water, alcohols, ethers and ketones, particularly preferably water alone. If anhydride copolymers are obtained, they are preferably hydrolyzed by addition of suitable amounts of water.

The polymerization conditions are known to the person skilled in the art. The acidic polymers (component B) can be obtained in a further embodiment by polymer-analogous reactions. Suitable polymer-analogous reactions are known to the person skilled in the art. For example, the preparation of the carboxylate-containing copolymers by appropriate functionalization of copolymers prepared by copolymerization; by reaction of polyhydric alcohols with higher-valent carboxylic acids possible.

Homo- or copolymers are generally to be understood as meaning branched or preferably linear compounds which have at least 3 repeat units, preferably more than 10 repeat units. The weight average molecular weight (Mw) of the homo- or copolymers used according to the invention is generally from 1000 to 5,000,000 g / mol, preferably from 1,000 to 500,000 g / mol, frequently from 1,000 to 100,000 g / mol, in particular from 1,000 to 50,000 g / mol.

In one embodiment, the polymer may also have low cross-linking, so that no molecular weight can be stated, although the polymer can be dispersed, emulsified or suspended in technically customary solvents. The molecular weight (Mw) can, for. B. be determined by gel permeation chromatography against a polystyrene standard.

The acidic polymers used as component B according to the invention are hydrophilic copolymers.

Preferably, a polymer composition is used which contains

a) 0 to 70% by weight, in particular 10 to 70% by weight, of a polar solvent (L), in particular water, b) 30 to 70% by weight of at least one acidic polymer component (B), c) 1 to 7,000 ppm of at least one alkine alkoxylate (A) which corresponds to the general formula (I) or (II),

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I)

H (-O-CHR ¹ -CH ₂ -) _n -O-CH ₂ -C≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (II),

wherein the radicals R ^{1 are} each independently H or methyl and the indices n and n 'independently of one another are numbers from 1 to 8, and d) 0.1 to 10 wt .-% of one or more additives and / or adjuvants ,

Preference is given to a polymer composition which contains water as solvent (L) and as polymer component (B) at least one polymeric or copolymeric compound composed of monomers from the group consisting of acrylic acid, methacrylic acid and maleic anhydride.

The subject matter is also a polymer composition which contains (L) water as solvent and contains as polymer component (B) at least one polymeric or copolymeric compound from the group of polyacrylic acids and polymethacrylic acids.

Preferred is a polymer composition containing as solvent (L) water and additionally 0.1 to 5 wt .-% of at least one further polar solvent.

Preference is given to a polymer composition which contains 0.01 to 10% by weight, in particular 0.1 to 5% by weight, of at least one surface-active substance as auxiliary.

Preference is given to a polymer composition which contains 1 to 10% by weight of one or more additives and / or auxiliaries from the group of water-soluble complexing agents and / or pH regulators.

The invention also relates to the use of a composition as described above for the preparation of building aids, dispersants or water treatment agents.

The invention also provides a polymer composition which contains water (or else water and contains no further solvent) as solvent (L) and as polymer component (B) at least one compound from the group of polyacrylic acids, polymethacrylic acids and copolymers of acrylic acid or methacrylic acid with monomers from the group of maleic anhydride (MSA), isobutene (IB), diisobutene (DIB), vinyl allyl ether, hydroxybuyl vinyl ether (HBVE) and polyethylene glycol acrylic acid polymers. Instead of MSA, its open derivatives can also be used.

The polymer compositions may contain as solvent (L) water and further from 0.01 to 20 wt .-%, in particular 0.1 to 10 wt .-% of an additional component (additives and / or auxiliaries). You can also contain as solvent (L) water and at least one other polar solvent. For example, they may contain water as solvent (L) and a water-soluble complexing agent (K) as additional component.

The polymer composition according to the invention preferably contains water as solvent (L), the polymer composition generally being used as a concentrated polymer composition, ie. H. having a polymer content of at least 30% by weight, in particular at least 40% by weight, preferably at least 45% by weight.

The solvent component (L) used for the polymer composition according to the invention is preferably a polar solvent, in particular water, in an amount of 0 to 70% by weight, preferably 20 to 60% by weight, in particular 30 to 50% by weight. , The water can also be used together with other solvents. The percentages here and below always refer to the amount of all components of the composition.

The polymer compositions often still contain one or more additives or auxiliaries, even if their addition is not necessary in every case. The amount of such additives is often 0 to 20 wt .-%, preferably 0.01 to 10% by weight and particularly preferably 0.1 to 10 wt .-%.

Adjuvants are in particular a surface-active substance. Preferably, 0.01 to 10 wt .-% and particularly preferably 0.05 to 8 wt .-% of the surfactant used. Examples of suitable surfactants include conventional anionic or nonionic surfactants. It can also be used several different surfactants. Among the surfactants, a suitable choice can be made depending on the desired application of the polymer composition. Nonionic and anionic surfactants are preferably used. The following examples are intended to explain the invention in more detail:

The following commercial products were used in the following experiments:

Commercially available corrosion inhibitor (I)

(Ethoxylated propargyl alcohol with 1 to 3 ethylene oxide units, water content not more than 0.5% by weight, manufacturer eg BASF)

Commercially available corrosion inhibitor (II) (solution of propoxylated propargyl alcohol with 1 to 3 propylene oxide units, water content 33% by weight, manufacturer eg BASF)

Commercially available corrosion inhibitor (III) (ethoxylated butynediol having 1 to 5 ethylene oxide units, water content 0.5% by weight)

Commercially available corrosion inhibitor (IV) (propoxylated butynediol having 1 to 5 propylene oxide units, water content 0.8% by weight)

example 1

Determination of Inhibition Efficiency of Inhibitors in Acid Medium

The following test shows the extent to which the dissolution of iron from stainless steel surfaces and the pitting tendency of a solution which has been brought into contact with a steel surface for a long time is suppressed or completely prevented by the addition of a substance.

a) Preparation of the test sheets:

For the tests several sheets of stainless steel 1.4541 (XβCrNiTi 18-10), stainless steel 1.4571 (X6CrNiMoTi17-12-2) and stainless steel 1.4539 (X1 NiCrMoCu32-28-7) of size 50 mm x 20 mm x 2 mm were used. Investigated were also center-welded corrosion samples (50 mm x 20 mm x 2 mm), which were installed in the liquid and in the vapor space. To evaluate a possible susceptibility to stress corrosion cracking, the samples of materials 1.4541 and 1.4571 were roughly ground on one side. b) The metal samples were cleaned for the tests as follows:

The panels were easily wiped with ethyl acetate. The thus pretreated sheet is at a voltage of 10 volts in a degreasing bath of the following components

20 g NaOH p.a.

22 g Na ₂ CO ₃ pa 16 g Na ₃ PO ₄ × 12 H ₂ O pa 1 g EDTA tetrasodium salt, powder

0.5 g nonionic surfactant (ethoxylated nonylphenol, approx. 10 EO units)

immersed between the electrodes and connected as a cathode. The voltage is adjusted so that the current is 1 A. After 30 seconds, the plate is removed and rinsed under running demineralised water for five seconds, blown off with air and used immediately for testing purposes. The sheets will be used directly in the corrosion test without further storage, because otherwise the re-forming oxide layer falsifies the result of the corrosion test.

c) Corrosion test (surface corrosion and pitting tendency)

The test electrolyte used is a polymer composition (Ia) according to the invention. It is an unneutralized, 50% solution of a radically polymerized, aqueous Homopolyacrylsäure (M _w 1,000-20,000 g / mol, Restacrylsäu content <2000 ppm, solids content 50%) of freshly distilled acrylic acid at pH 1-2.5 used; this polymer solution contains no phosphorus-containing additives; Sodium persulfate solution serves as a starter; the polymerization time is 14h; Solution (1a).

The test electrolyte used is furthermore a polymer composition (Ib) according to the invention: Unneutralized 30% solution of a free-radically polymerized aqueous polyacrylic-co-methacrylic acid (M _w 1,000-50,000 g / mol, residual acrylic acid content <2,000 ppm, solids content 30%) from 1 part fresh distilled acrylic or 3 parts of freshly distilled methacrylic acid at pH 2.1-3.5 used; this polymer solution contains no phosphorus-containing additives; Sodium persulfate solution as a starter; Polymerization time 20h; Solution (1b).

The test electrolyte used is furthermore a polymer composition (Ic) according to the invention: Unneutralized 30% solution of a free-radically polymerized aqueous polyacrylic-co-maleic acid (M _w 3,000-50,000 g / mol, residual acrylic acid content <2,000 ppm, solids content 30%) from 1 part fresh distilled acrylic or 1 part of maleic anhydride used at pH 2.2-4; this polymer solution contains no phosphorus containing additives; Hydrogen peroxide solution as a starter; Polymerization time 22h; Solution (1c).

The corrosion inhibitor to be tested (component A) is dissolved in the original polymer solution in the form of a solution or as a pure liquid product in the amount indicated in Table 1. It was possible to determine by means of quantitative GC analysis (area% relative to a calibration substance) before, during (every 2 hours) and after the polymerization a corrosion inhibitor content of> 95% (at the initial charge), i. the corrosion inhibitors (I-IV) do not consume during the polymer synthesis.

The stainless steel sheet is used immediately after weighing. In each case a prepared sheet is hung in a filled with solution 1a, solution 1b and solution 1c 250 ml beaker with nitrogen inertization, so that it is completely covered by the solution and dormant. The beaker is stored at 60 ^° C. for a period of 28 days.

The plates are then removed from the solutions, rinsed with demineralized water and blown dry with air. Subsequently, the mass is determined in each case. The efficiency (E) is determined by the mass loss Δm _p . ^ Relative to the loss of mass in a corresponding control experiment without inhibitor Am ₀ .

The following applies: E = (Am ₀ - Am ^ _obe ) I Am ₀ .

For each measured value a double determination is carried out. The results are summarized in Table 1 below.

The mean linear corrosion rate v / mm year was tested without findings (<0.001) for the vapor space.

Table 1 Corrosion Inhibitor I in Polymer Solution (1a)

Material Inhibitor Medium linear inhibition. Remarks

[ppm] Corrosion rate in efficiency

on

1.4571 - 0.007 0

1.4539 - 0.001 0 without findings

1.4541 1000 0.09 22-27 Pitting (2-5

Points / cm ² ), trough-shaped

Attack, crevice corrosion

1.4571 1000 0.005 28-33

1.4539 1000 0.001 n.b. without findings

1.4541 5000 <0.001> 95 without findings

1.4571 5000 <0.001> 95 without findings

1.4539 5000 <0.001 n.b. without findings

Table 2 Corrosion inhibitor I in polymer solution (1b)

Material Inhibitor Medium linear inhibition. Remarks

[ppm] Corrosion rate in fluid efficiency [%]

[v / mm year]

1.4541 - 0.21 0 Pitting (9-18

Points / cm ² ), trough-shaped attack, crevice corrosion

1.4571 - 0.012 0

1.4539 - 0.008 0 without findings

1.4541 1000 0.002> 95% no pitting

1.4571 1000 0.003 75 without findings

1.4539 1000 <0.001 n.b. without findings

1.4541 5000 <0.001> 95 no laxity

1.4571 5000 <0.001> 95 without findings

1.4539 5000 <0.001> 95 without findings Table 3 Corrosion inhibitor I in polymer solution (1c)

Material Inhibitor Medium linear inhibition. Remarks

[ppm] Corrosion rate in fluid efficiency r lo // ° 1J

[v / mm year]

1.4541 _ 0.195 0 Pitting (9-18

Points / cm ² ), trough-shaped

Attack, crevice corrosion

1.4571 - 0.012 0

1.4539 - 0.008 0 without findings

1.4541 1000 <0.001> 95% no pitting

1.4571 1000 <0.001> 95% without findings

1.4539 1000 <0.001 n.b. without findings

These experiments show that the addition of already 1,000 ppm of the corrosion inhibitor (I), the mass removal by surface corrosion decreases significantly, with the addition of 5,000 ppm, it can be seen that the pitting sensitivity is significantly reduced. This component (A), which can be used before or during the preparation of the acidic polymer, appears suitable for permanent protection of the stainless steel surfaces from the aggressive aqueous polymer solutions at pH <5.

It could be demonstrated that with the described components (A) already in the dosage range of 100-5000 ppm complete suppression of any form of corrosion (> 95% inhibition efficiency) on the stainless steel surfaces (1.4541, 1.4571 and 1.4539) in all investigated polymer solutions (1a). c).

It is of particular advantage that component (A) can be added even before the polymerization.

The polymer composition according to the invention also satisfies the following requirements:

a) It is due to the average viscosity (preferably EO / PO n <10) easily processable for many applications and additionally corrosion inhibiting; b) it is still corrosion-inhibiting even at elevated temperature (eg 120 ^° C.); c) it is color-neutral even after prolonged contact with the metal surface of storage or transport vessels; d) it is available without complicated process steps; e) to form water-soluble without turbidity.

Claims

claims

A polymer composition containing the following components:

a) from 10 to 70% by weight of a solvent (L), b) from 30 to 70% by weight of at least one acidic polymer component (B), c) from 1 to 7000 ppm of at least one alkine alkoxylate (A) corresponding to the general formula ( I) or (II),

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I)

where the radicals R ^{1 are} each, independently of one another, H or methyl and the indices n and n 'independently of one another represent numbers from 1 to 10,

d) 0 to 20 wt .-% of one or more additives and / or adjuvants.

2. Polymer composition according to claim 1, characterized in that it contains:

a) from 20 to 60% by weight of a polar solvent, b) from 30 to 60% by weight of at least one acidic polymer component (B), c) from 10 to 5,000 ppm of at least one alkine alkoxylate (A) corresponding to the general formula (I) or (II) corresponds

HC≡C-CH ₂ -O (-CH ₂ -CHR ¹ -O-) _n H (I)

where the radicals R ^{1 are} each independently H or methyl and the indices n and n 'independently of one another are numbers from 1 to 10, d) 0 to 10% by weight of one or more additives and / or auxiliaries.

3. Polymer composition according to one of claims 1 or 2, characterized in that it contains as solvent (L) water and as polymer component (B) at least one polymeric or copolymeric compound composed of monomers from the group of acrylic acid, methacrylic acid and maleic anhydride.

4. Polymer composition according to one of claims 1 to 3, characterized in that it contains as solvent (L) water and as polymer component (B) at least one polymeric or copolymeric compound from the group of polyacrylic acids and polymethacrylic acids.

5. Polymer composition according to one of claims 1 to 4, characterized in that it contains 100 to 5,000 ppm of Alkinalkoxylates as component A, wherein this contains 1 to 5 ethylene oxide or propylene oxide units.

6. Polymer composition according to one of claims 1 to 5, characterized in that it contains as solvent (L) water and additionally 0.1 to 5 wt .-% of at least one further polar solvent.

7. Polymer composition according to any one of claims 1 to 6, characterized in that it contains 30 to 70 wt .-% of polymer component (B), water as a solvent (L) and 1 to 10 wt .-% of additives and / or excipients from the group of water-soluble complexing agents, surface-active substances and pH regulators.

8. Polymer composition according to any one of claims 1 to 7, characterized in that it contains 30 to 70 wt .-% of polymer component (B), which is a polyacrylic acid or a polymethacrylic acid.

Polymer composition according to any one of Claims 1 to 8, characterized in that it contains 45 to 55% by weight of polyacrylic acid, 45 to 55% by weight of water and 0.1 to 5% by weight of one or more additives and / or or additives from the group of surface-active substances and / or pH regulators.

10. A process for preparing a polymer composition according to one of claims 1 to 9, characterized in that one prepares an acidic polymer component (B) in the presence of a Alkinalkoxylates (A) of the general formula (I) or (II) by polymerization, and optionally mixed with a solvent (L) and / or additives and / or auxiliaries.

11. Use of a composition according to any one of claims 1 to 9 for the preparation of building aids, dispersants or water treatment agents.