Aqueous adhesive compositions stabilized against microbial infestation

Abstract

The invention relates to aqueous adhesive compositions which contain at least the following components: (a) 1 to 95 wt. %, calculated as the solids content of a base component, containing: (a1) at least one polymeric organic binder, selected from acrylate, styrene, vinyl acetate, vinyl propionate and / or urethane homopolymers or copolymers, or any mixture thereof, and / or (a2) at least one polysaccharide thickener, selected from the group consisting of cellulose ethers, such as methyl cellulose, carboxyalkyl cellulose, in particular carboxymethyl cellulose, hydroxyalkyl cellulose, alkyl hydroxyalkyl cellulose, starch, in particular potato starch, starch ethers, in particular modified amylose and / or amylopectin, guar ethers, dextrins and mixtures of said compounds; (b) water; and (c) 0.03 to 1.4 wt. % guanidine and / or at least one salt of guanidine, wherein the proportion by weight refers to the content of guanidine in the total aqueous adhesive composition.

Description

[0001] Thor GmbH August 14, 2025

[0002] THO3 2024PC

[0003] Water-based adhesive compositions stabilized against microbial infestation

[0004] The invention relates to aqueous adhesive compositions comprising at least the following components: (a) 1 to 95 wt.%, calculated as solids content, of a base component comprising: (a) at least one polymeric organic binder selected from acrylate, styrene, vinyl acetate, vin propionate and / or urethane homo- or copolymers or any mixture thereof, and / or (a2) at least one polysaccharide thickener selected from the group consisting of cellulose ether, such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch ethers, in particular modified amylose and / or amylopectin, guarethem, dextrins and mixtures of these compounds, (b) water and (c) 0.03 to 1.4 wt.-% guanidine and / or at least one salt of guanidine, wherein the weight fraction refers to the guanidine content in the entire aqueous adhesive composition. The adhesive compositions are characterized in that they have a pH value in the range of pH 7.5 to 12.0. The present invention further relates to a process for producing aqueous adhesive compositions, as well as a process for stabilizing aqueous adhesive compositions against microbial attack.

[0005] Aqueous technical products, such as aqueous adhesive compositions, are typically manufactured using natural or biodegradable raw materials. These raw materials and the water used as a solvent are often contaminated with microorganisms such as bacteria, yeasts, and fungi. If these products are not preservatives, they can exhibit high microbial counts as early as one day after production.

[0006] To ensure that these products and, where applicable, their components used in their manufacture meet hygienic requirements, and thus guarantee the shelf life of the products, so-called biocides are usually added to the products or their components.

[0007] One class of biocides used to preserve aqueous adhesive compositions, or components thereof, are the so-called 3-isothiazolin-3-ones. This class of substances includes highly antimicrobial compounds with sometimes differing activity profiles. Synergistic combinations of different 3-isothiazolin-3-ones are often used to reduce the amount of biocide required. For example, WO 99 / 08530 Al proposes the combined use of methylisothiazolin-3-one and 1,2-benzisothiazolin-3-one.

[0008] Another class of biocides are the so-called alkylguanidinium salts and also polyguanidinium salts. For example, it is known from the "Directory of microbicides for the protection of materials", Springer 2005, pages 726 to 731, that medium- and long-chain guanidines and biguadinines, such as cocospropylenediamine-1,5-bis-guanidinium acetate, bis(guanidinooctyl)amine triacetate, poly(hexamethylene-biguanidine) hydrochloride, di(4'-chlorophenyldiguanido)hexane, chlorhexidine digluconate, and chlorhexidine diacetate, exhibit antimicrobial activity.

[0009] Furthermore, it is known to use such medium- and long-chain guanidine compounds together with other antimicrobial and / or fungicidal active ingredients. For example, combinations with 3-iodo-2-propynyl butylcarbamate or formaldehyde depot agents are known. EP 0 891 710 Al, for instance, teaches the combined use of dodecylguanidine hydrochloride and IPBC. However, the use of dodecylguanidine salts for preserving coating compositions and polymer dispersions has proven problematic; incompatibilities in the form of coagulation have been observed upon the addition of these salts.

[0010] Sometimes the use of conventional biocides or preservatives is not an option because these are increasingly subject to legal restrictions.

[0011] In this context, it has therefore already been proposed to provide shelf-stable dispersion paints without the use of conventional preservatives by increasing their pH value to effectively prevent microbial growth. A pH value of at least 10 is targeted, as microbial growth cannot be reliably prevented at lower pH values.

[0012] European patent EP 2 942 336 Bl protects an aqueous adhesive composition containing at least 50 wt% water, 0.1 to 4.0 wt% water glass, 0.1 to 7.0 wt% starch and / or starch derivatives, 0 to 15 wt% fillers, and polymer binders. The water glass is intended to raise the pH value of the aqueous composition to such an extent that preservatives can normally be omitted.

[0013] A disadvantage of the aforementioned preservation method, however, is the comparatively high pH values ​​required in the preparations, which necessitates particular care during handling. Furthermore, increased contamination by alkaliphilic germs—microorganisms that can survive and multiply under alkaline conditions—has recently been observed in these preparations.

[0014] Despite the numerous known combinations of active ingredients and the measures already taken, there is a growing demand, particularly due to increasing regulatory restrictions, for aqueous adhesive compositions stabilized against microbial infestation, which preferably do without or with a reduced content of classic preservatives or biocides, such as isothiazolinones, bronopol and pyrithione ions.

[0015] This task is solved by an aqueous adhesive composition containing at least the following components:

[0016] (a) 1 to 95 wt.%, preferably 10 to 90 wt.%, particularly preferably 15 to 85 wt.%, calculated as solid content, of a base component, comprising:

[0017] (a) at least one polymeric organic binder selected from acrylate, styrene, vinyl acetate, vinyl propionate and / or urethane homo- or copolymers, or any mixture thereof, and / or (a2) at least one polysaccharide thickener selected from the group consisting of cellulose etheme, such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch etheme, in particular modified amylose and / or amylopectin, guar ethers, dextrins and mixtures of these compounds,

[0018] (b) water and

[0019] (c) 0.03 to 1.4 wt.%, preferably 0.07 to 1.2 wt.%, particularly preferably 0.1 to 1.0 wt.% guanidine and / or at least one salt of guanidine, wherein the wt. percentage refers to the guanidine content in the total aqueous adhesive composition, characterized in that the adhesive composition has a pH value in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, particularly preferably in the range of pH 8.5 to 11.

[0020] The aqueous adhesive compositions according to the invention, which are stabilized against microbial attack, require significantly fewer, and in some cases even no, preservatives than those typically used in such products. Nevertheless, due to the surprisingly effective interaction of guanidine or the guanidine salt and the corresponding pH value in the range of 7.5 to 12.0, these products are characterized by excellent resistance to microbial attack, particularly during storage. This significantly improves the environmental compatibility of the aforementioned aqueous adhesive compositions, and they also exhibit all known properties relating to good and safe processing characteristics.Furthermore, the adhesive compositions according to the invention are particularly protected against infestation by adapted alkaliphilic microorganisms, especially alkaliphilic bacteria, as well as neutrophilic to weakly alkaliphilic bacteria. This allows them to be formulated with a less strongly alkaline composition, which is advantageous with regard to reliable processing.

[0021] According to a preferred embodiment of the invention, the aqueous adhesive composition is essentially free, preferably entirely free, of preservatives selected from the group consisting of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, N-butyl-1,2-benzisothiazolin-3-one, N-methyl-1,2-benzisothiazolin-3-one, octylisothiazolinone, dichlorooctylisothiazolinone, dithiobisbenzmethylamide, formaldehyde and formaldehyde releasers, quaternary ammonium compounds, bronopol,

[0022] Dibromonitrilopropionamide, dibromodicyanobutane, iodopropynylbutylcarbamate, thiabendazole, sodium pyrithione, zinc pyrithione, o-phenylphenol and combinations of these.

[0023] Essentially free in this context means that the adhesive composition contains a total amount of less than 10 ppm, preferably less than 5 ppm, particularly preferably less than 1 ppm, based on the total composition.

[0024] In the context of the present invention, an "aqueous adhesive composition" is understood to be a composition that can optionally be used as an adhesive itself, but from which a ready-to-use adhesive is generally obtained by dilution with a dispersion or solvent, preferably water. The term "adhesive" 1Within the scope of the present invention, "is" is understood in a narrower sense and includes glues, pastes, dispersion adhesives, contact or pressure-sensitive adhesives, but excludes paints, color concentrates, dyeing preparations, plasters, varnishes, glazes and slurries.

[0025] The aqueous adhesive composition according to the invention contains, based on the total adhesive composition, 1 to 95 wt.%, preferably 10 to 90 wt.%, particularly preferably 15 to 85 wt.%, calculated as solid content, a base component which contains or consists of the component(s) (al) and / or (a2).

[0026] In the context of the present invention, component (al) is at least one polymeric organic binder selected from the group consisting of acrylate, styrene, vinyl acetate, vinyl chloride, vinyl propionate and / or urethane homoder copolymers or any mixture thereof.

[0027] Accordingly, suitable organic binders include those in which the water-dispersed or water-dispersible polymeric organic binder is formed from the same or different monomers, wherein at least one of the monomers is, for example, an acrylic acid ester, methacrylic acid ester, acrylic acid, methacrylic acid, vinyl acetate, vinyl chloride, acrylonitrile, or a vinylaromatic compound, particularly styrene. Vinyl acetate / olefin copolymers, especially vinyl acetate / ethylene copolymers, are particularly preferred for the aqueous adhesive compositions according to the invention in which an organic binder is present.

[0028] By general definition, "copolymers" are understood to be fully synthetic polymers formed from more different monomers than would have been necessary for polymerization according to the respective reaction mechanism. Preferably, the copolymers usable within the scope of the present invention are composed of two different monomers.

[0029] Preferred copolymers within the scope of the present invention are, for example, copolymers based on vinyl esters, in particular copolymers of vinyl acetate with ethylene and / or vinyl chloride and / or further vinyl esters such as vinyl laurate, versatic acid vinyl esters, vinyl pivalate and / or esters of maleic / fumaric acid, furthermore copolymers of vinyl esters saturated with Crf- alkylcarboxylic acids with ethylene, vinyl chloride and / or further vinyl esters. In addition, copolymers based on styrene, acrylic acid esters, methacrylic acid esters and / or vinyl chloride are suitable, e.g. styrene-butadiene copolymers, vinyl chloride-ethylene copolymers or styrene-acrylic acid ester copolymers (styrene acrylates).

[0030] According to a preferred embodiment of the invention, the base component (al) is therefore at least one polymeric organic binder selected from copolymers of vinyl acetate with ethylene and / or vinyl chloride and / or further vinyl esters, such as vinyl laurate, versatic acid vinyl esters, vinyl pivalate and / or esters of maleic / fumaric acid, copolymers of vinyl esters saturated with alkylcarboxylic acids with ethylene, vinyl chloride and / or further vinyl esters, and copolymers based on styrene, acrylic acid esters, methacrylic acid esters and / or vinyl chloride, or any mixture thereof. According to a particularly preferred embodiment of the invention, the base component (al) is at least one polymeric organic binder selected from vinyl acetate-acrylate copolymers, vinyl acetate-ethylene copolymers, styrene-butadiene copolymers, vinyl chloride-ethylene copolymers, styrene-acrylic acid ester copolymers, or any mixture thereof.

[0031] In the context of the present invention, component (a2) is at least one polysaccharide thickener selected from the group consisting of cellulose etheme, such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch etheme, in particular modified amylose and / or amylopectin, guar ethers, dextrins and mixtures of these compounds.

[0032] According to a preferred embodiment of the invention, the base component (a2,) is selected from the group consisting of hydroxy ethylcellulose, hydroxypropylcellulose, methylhydroxypropylcellulose and methylhydroxyethylcellulose, in particular methylhydroxy ethylcellulose.

[0033] Within the scope of the present invention, the values ​​"wt.%" refer to the entire aqueous adhesive composition.

[0034] In the context of the invention, "at least one salt of guanidine" means that the adhesive composition contains one or two, three, four, five or six, i.e., also a mixture of salts of guanidine.

[0035] The aqueous adhesive composition according to the invention contains, as component (c), guanidine and / or at least one salt of guanidine, in an amount in the range of 0.03 to 1.4 wt.%, wherein the specified wt. percentage refers to the guanidine content in the entire adhesive composition, thus providing stabilization against microbial attack, particularly during storage. The amount of component (c) required for stabilization is determined by a person skilled in the art, depending on the specific composition, using methods familiar to them. The aqueous adhesive compositions stabilized against microbial attack exhibit improved stability against microbial attack compared to non-stabilized aqueous compositions, i.e., compositions that contain no guanidine or no salt of guanidine, or that contain guanidine or its salt in insufficient quantities, and are therefore less prone to microbial contamination.Within the scope of the invention, it was found that guanidine amounts of up to 1.5 wt.%, preferably up to 1.2 wt.%, and particularly preferably up to 1 wt.%, are sufficient to ensure stabilization of the composition against infestation by microorganisms. Higher amounts than, for example, 1.4 wt.% guanidine are not desirable from a practical point of view with regard to stabilization, and especially from an economic point of view.

[0036] The aqueous adhesive composition according to the invention is characterized in that the component (c) is contained in the composition in the range of 0.03 to 1.4 wt.%, preferably in the range of 0.07 to 1.2 wt.%, particularly preferably in the range of 0.1 to 1.0 wt.%, wherein the specified weight percentage refers to the content of unsubstituted guanidine according to the formula shown below: in the entire aqueous composition. Therefore, when determining the guanidine content, in the case of guanidine salts, only the guanidine content is considered, without taking any counterion into account.

[0037] The guanidine salt that may be contained in the aqueous adhesive composition is preferably at least one guanidine salt selected from the group consisting of guanidine hydrochloride, guanidine carbonate, guanidine nitrate, guanidine sulfate, guanidine thiocyanate, guanidine phosphate, guanidine hydrogen carbonate, guanidine formate, guanidine acetate, guanidine silicate, and / or guanidine citrate. "At least one guanidine salt" means that one, two, three, four, five, or even more guanidine salts may be present. The guanidine salts according to the present invention are unsubstituted guanidine or guanidinium salts of the general formula shown below: where n is equal to 1, 2 or 3, and where the counterion X 11 'for example chloride, carbonate, nitrate, sulfate, thiocyanate, phosphate, bicarbonate, formate, acetate or citrate.

[0038] According to a preferred embodiment of the invention, the aqueous adhesive composition contains, as component (c), guanidine hydrochloride and / or guanidine carbonate; according to a particularly preferred embodiment of the invention, the aqueous adhesive composition contains, as component (c), guanidine carbonate.

[0039] The pH value of the aqueous adhesive composition is generally in the range of pH 7.5 to 12. According to a preferred embodiment of the invention, the aqueous adhesive composition is characterized in that it has a pH value in the range of 8 to 11.5, preferably in the range of pH 8.5 to 11. By adjusting the pH value to a value in the range of 8.5 to 11, more skin-friendly compositions and thus adhesives with additionally improved properties are obtained. In particular, less stringent requirements apply to the handling of the compositions according to the invention.

[0040] Adjusting the pH value to the required range can be achieved using methods familiar to those skilled in the art. This can be done, for example, by using guanidine carbonate as a guanidine salt. Similarly, the pH value can be adjusted to the required range by adding alkaline substances, also known as alkali adjusters. Such pH-adjusting compounds are known to those skilled in the art; the required amount can vary widely and can be determined using familiar methods. Examples of alkali adjusters include:

[0041] • Guanidine carbonate,

[0042] • Alkali metal hydroxides such as lithium, sodium and / or potassium hydroxide,

[0043] • Alkaline earth metal hydroxides such as magnesium, calcium, and / or barium hydroxide, ammonium hydroxide, xonotlite and / or ettringite (Ca6[Al(OH)e]2(SO4 x 26 H2O)),

[0044] • Water glass such as sodium, lithium and potassium water glass, or mixtures thereof,

[0045] • Siliconates, such as alkali metal alkyl siliconates or alkaline earth alkyl siliconates, in particular compounds according to the general formula R-Si(OH)2OM A or [R-Si(OH)2O]2M E designated, wherein M A for an alkali metal such as lithium, sodium, potassium, M E where R represents an alkaline earth metal, such as magnesium or calcium, and R represents an alkyl group, such as methyl, ethyl, n-propyl, i-propyl, n-butyl or i-butyl.

[0046] • Buffer systems, for example based on at least one phosphate or polyphosphate salt, preferably K3PO4 or NasPCrf, and at least one alkali hydroxide, preferably lithium, sodium and / or potassium hydroxide,

[0047] • Alkali and / or alkaline earth carbonates and / or hydrogen carbonates,

[0048] • Ammonia and ammonium compounds,

[0049] • Amines, amino compounds and amino alcohols.

[0050] According to a preferred embodiment of the invention, the pH value is adjusted to the claimed range using guanidine carbonate and / or sodium carbonate.

[0051] According to one embodiment of the invention, the adhesive composition is characterized in that it further comprises as component (d) one or more carbonate compound(s) selected from the group consisting of sodium hydrogen carbonate, sodium carbonate, potassium hydrogen carbonate, potassium carbonate, ammonium hydrogen carbonate and ammonium carbonate.

[0052] As component (d) the adhesive composition according to the invention contains one or more carbonate compound(s) selected from the group consisting of sodium hydrogen carbonate (NaHCCL), sodium carbonate (Na2COs),

[0053] Potassium hydrogen carbonate (KHCO3), potassium carbonate (K2CO3),

[0054] Ammonium hydrogen carbonate (NH4HCO3) and ammonium carbonate (NH^CCh). "Several" here means that the composition can contain two, three, four, five, or six of the mentioned carbonate compounds.

[0055] According to a preferred embodiment of the invention, the adhesive composition contains as component(s) (d) sodium carbonate (Na₂CO₃) and / or sodium bicarbonate (NaHCl). In the case of the use of these carbonate compounds, compositions with additionally improved antimicrobial properties are obtained.

[0056] Within the scope of the present invention, both the quantities of components (c) and (d) and the weight ratios of components (c) and (d) to each other are specified. Unless otherwise stated, the quantities refer to the lead structures, guanidine (CN3H5) as component (c) and carbonate (CO3), respectively. 2). Likewise, when determining the specified weight ratios, the content of guanidine, without consideration of any counterion, as component (c), and the content of carbonate, without consideration of any counterion, as component (d), in the composition are taken as a basis.

[0057] The amount of component (d) containing one or more carbonate compounds in the composition according to the invention can vary over a wide range and is generally in the range of 100 ppm to 50,000 ppm, preferably in the range of 500 ppm to 25,000 ppm, and particularly preferably in the range of 1,000 ppm to 10,000 ppm, based on the amount of carbonate in the adhesive composition.

[0058] The weight ratio of component (c) to component (d) is generally in the range of 1 : 14 to 54 : 1, preferably in the range of 1 : 8.6 to 21 : 1, particularly preferably in the range of 1 : 8 to 8 : 1 and most preferably in the range of 1 : 3.4 to 1.6 : 1, wherein the determination of the weight ratio is based on the content of guanidine and carbonate in the total composition.

[0059] In the context of the present invention, an aqueous adhesive composition means that the composition contains water, which makes it somewhat susceptible to microbial contamination. The adhesive composition generally has a water content of at least 5 wt.%, preferably at least 10 wt.%, and particularly preferably at least 15 wt.%, wherein the components forming the adhesive composition always add up to 100.0 wt.%. As already described in the introduction, such aqueous compositions are usually produced using natural or biodegradable raw materials. These raw materials and the water used as a solvent are often contaminated with microorganisms such as bacteria, yeasts, and fungi. The water content in the aqueous adhesive composition can vary over a wide range and is generally in the range of 5 to 95 wt.%, preferably in the range of 10 to 90 wt.%.-% and particularly preferably in the range of 15 to 85 wt.%, wherein the components forming the adhesive composition always add up to 100.0 wt.%.

[0060] The subject matter of this invention further relates to a method for producing the aqueous adhesive composition according to the invention, comprising mixing the components defined above.

[0061] The present invention further relates to a method for stabilizing an aqueous adhesive composition against microbial infestation, which comprises the following process steps:

[0062] (i) Providing an aqueous adhesive composition containing:

[0063] (a) 1 to 95 wt.%, calculated as solid content, of a base component, containing:

[0064] (al) at least one polymeric organic binder selected from acrylate, styrene, vinyl acetate, vin propionate and / or urethane homo- or copolymers or any mixture thereof, and / or

[0065] (a2) at least one polysaccharide thickener selected from the group consisting of cellulose ethers such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch ethers, in particular modified amylose and / or amylopectin, guar ethers, dextrins and mixtures of these compounds, (ii) mixing at least one salt of guanidine with the aqueous adhesive composition and

[0066] (iii) optionally adjusting the pH value, characterized in that the stabilized aqueous adhesive composition has a pH value in the range of pH 7.5 to 12.0, preferably from pH 8 to 11.5, particularly preferably from pH 8.5 to 11, and further characterized in that the amount of the guanidine salt or guanidine salts is in the range of 0.03 to 1.4 wt.%, preferably in the range of 0.07 to 1.2 wt.%, particularly preferably in the range of 0.1 to 1.0 wt.%, wherein the weight fraction refers to the guanidine content in the total aqueous composition.

[0067] The process according to the invention is advantageously characterized by the fact that it enables the production of aqueous adhesive compositions stabilized against microbial attack, which, due to their composition, require significantly fewer, and in some cases even no, preservatives such as those typically contained in aqueous adhesive compositions. Nevertheless, due to the surprisingly effective interaction of the at least one guanidine salt or the resulting guanidine and the corresponding pH value in the range of pH 7.5 to 12.0, the aqueous adhesive compositions exhibit excellent resistance to microbial attack, particularly during storage. This significantly improves the products with regard to their environmental compatibility.

[0068] In step (i) of the method according to the invention, the aqueous adhesive composition to be stabilized against microbial attack is provided. Stabilizing against microbial attack, within the scope of the present invention, means that in an unstabilized state, particularly during storage, it is prone to microbial attack and thus deteriorates.

[0069] The aqueous adhesive composition provided in step (i) is mixed with at least one guanidine salt in process step (ii). The amount of guanidine salt required for stabilization is determined by a person skilled in the art, depending on the specific product, using methods familiar to them. The aqueous adhesive compositions stabilized against microbial attack exhibit improved stability against microbial attack compared to non-stabilized aqueous adhesive compositions, i.e., compositions that do not contain a guanidine salt or guanidine, or that contain an insufficient amount of the guanidine salt or guanidine, and are therefore less prone to microbial contamination.

[0070] The amount of guanidine salt(s) used in process step (ii) can vary depending on the composition provided and is in the range of 0.03 to 1.4 wt.%, preferably in the range of 0.07 to 1.2 wt.%, particularly preferably in the range of 0.1 to 1.0 wt.%, wherein the weight fraction refers to the guanidine content, without taking into account any counterion, in the total aqueous adhesive composition.

[0071] According to a preferred embodiment of the invention, guanidine hydrochloride and / or guanidine carbonate are used in process step (ii), and according to a particularly preferred embodiment of the invention, guanidine carbonate is used.

[0072] In process step (iii) of the process for stabilizing the aqueous adhesive composition, the pH is optionally adjusted so that the composition has a pH value in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, and particularly preferably in the range of pH 8.5 to 11. "Optionally" here means that the pH value is already in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, and particularly preferably in the range of pH 8.5 to 11, due to the composition of the adhesive composition or the guanidine salt used in process step (ii), so that adjustment is not necessary.

[0073] The present invention further relates to a method for producing an aqueous adhesive composition stabilized against microbial infestation, comprising the following process steps:

[0074] (i) Providing an aqueous adhesive composition as defined above,

[0075] (ii) Mixing at least one salt of guanidine with the aqueous adhesive composition such that the amount of the guanidine salt, based on the guanidine content in the total aqueous composition, is in the range of 0.03 to 1.4 wt.%, and

[0076] (iii) optionally adjusting the pH value, characterized in that the aqueous adhesive composition produced has a pH value in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, particularly preferably in the range of pH 8.5 to 11.

[0077] The manufacturing process according to the invention is advantageously characterized in that aqueous adhesive compositions stabilized against microbial infestation can be produced with it, which, due to their

[0078] Composition significantly less, in some cases even none

[0079] Preservatives, such as those commonly included in these compositions for preservation, are required. Nevertheless, the aqueous

[0080] Adhesive compositions are characterized by excellent resistance to microbial infestation, especially during storage, due to the surprisingly effective interaction of at least one guanidine salt and the corresponding pH value in the range of pH 7.5 to 12.0.

[0081] In step (i) of the manufacturing process according to the invention, the aqueous adhesive composition to be stabilized against microbial attack is provided. Stabilizing against microbial attack, within the scope of the present invention, means that in its unstabilized state, it is prone to microbial attack, particularly during storage, and thus deteriorates.

[0082] The aqueous adhesive composition provided in step (i) is then mixed with at least one guanidine salt in process step (ii). The amount of guanidine salt required for stabilization is determined by a person skilled in the art, depending on the specific composition provided, using methods familiar to them. The aqueous adhesive composition stabilized against microbial attack exhibits improved stability against microbial attack compared to non-stabilized compositions, i.e., compositions that do not contain a salt of unsubstituted guanidine or that contain an insufficient amount of the guanidine salt, and is therefore less prone to microbial contamination. The amount of guanidine salt(s) used in process step (ii) can vary widely depending on the adhesive composition provided and ranges from 0.03 to 1.4 wt.-%, preferably in the range of 0.07 to 1.2 wt.%, particularly preferably in the range of 0.1 to 1.0 wt.%, wherein the weight fraction refers to the content of guanidine, without taking into account any counterions, in the total aqueous adhesive composition.

[0083] According to a preferred embodiment of the invention, in process step (ii) guanidine hydrochloride and / or guanidine carbonate, according to a particularly preferred embodiment of the invention, guanidine carbonate, is used.

[0084] In process step (iii) of the process for producing the aqueous adhesive composition, the pH is optionally adjusted so that the produced composition has a pH value in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, and particularly preferably in the range of pH 8.5 to 11.0. "Optionally" here means that the pH value is already in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, and particularly preferably in the range of pH 8.5 to 11.0, due to the composition of the adhesive composition or the guanidine salt used in process step (ii), so that adjustment is not necessary.

[0085] The invention further relates to the use of guanidine and / or at least one salt of guanidine in an aqueous adhesive composition having a pH value in the range of pH 7.5 to 12.0, preferably in the range of pH 8 to 11.5, particularly preferably in the range of pH 8.5 to 11, in an amount in the range of 0.033 to 2.0 wt. %, preferably in the range of 0.07 to 1.7 wt. %, particularly preferably in the range of 0.1 to 1.4 wt. %, wherein the weight percentage refers to the content of guanidine, without taking into account any counterion, in the entire aqueous composition, for stabilizing the aqueous adhesive composition against microbial attack.

[0086] Advantageously, the use of guanidine or at least one guanidine salt in the aqueous adhesive composition defined above, as described in the invention, eliminates the need for conventional preservatives typically contained in such compositions for container preservation. This allows the adhesive compositions to be improved with regard to their

[0087] Environmental compatibility significantly improved. The stressed aqueous

[0088] Furthermore, adhesive compositions exhibit all known properties relating to good and safe processing characteristics; they are also particularly protected against infestation by adapted alkaliphilic microorganisms as well as against neutrophilic to weakly alkaliphilic microorganisms.

[0089] The following examples serve to further illustrate the present invention:

[0090] To demonstrate the stabilization of aqueous adhesives against microbial infestation, various adhesives with different pH values ​​were treated with different amounts of guanidine salts and tested for their stability against microbial infestation:

[0091] The adhesives tested were as follows:

[0092] Adhesive 1: Fabric adhesive with a pH value of 9.5, based on vinyl acetate / VeoVa® / acrylate copolymer, without the addition of the otherwise usual conventional preservatives.

[0093] Adhesive 2: Wallpaper adhesive with a pH value of 8.9, based on vinyl acetate / ethylene copolymer, without the addition of the otherwise usual conventional preservatives.

[0094] Adhesive 3: Woodchip wallpaper adhesive with a pH value of 7.7, based on vinyl acetate / ethylene copolymer, without the addition of the otherwise usual conventional preservatives.

[0095] Adhesive 4: Starch adhesive with a pH value of 7.7, without the addition of the otherwise usual conventional preservatives.

[0096] Procedure:

[0097] Adhesives 1 to 4 were mixed with different concentrations of the guanidinium salts to be tested and homogenized.

[0098] The resulting batches of the prepared adhesives were each inoculated with a mixture of different bacterial or yeast strains as an inoculum. A total of three bacterial mixtures of varying compositions were used. Bacterial mixture 1 consisted of bacteria commonly used as a standard in laboratory tests for the microbial stability of technical, aqueous products. Bacterial mixture 2 consisted of bacterial mixture 1 plus field-specific bacterial isolates isolated from contaminated, technical, aqueous products. Bacterial mixture 3 consisted of so-called alkaliphilic bacteria isolated from contaminated alkaline technical products. Bacterial mixture 1:

[0099] Alcaligenes faecalis NCIMB 13145

[0100] Aeromonas hydrophila DSM 6173

[0101] Escherichia coli DSM 13631

[0102] Burkholderia cepacia DSM 9241

[0103] Staphylococcus aureus DSM 799

[0104] Pseudomonas aeruginosa DSM 50071

[0105] Pseudomonas putida DSM 13624

[0106] Bakteriengemisch 2:

[0107] Bakterien-Gemisch 1

[0108] Pseudomonas spp. (Pseudomonas oleovorans group) DSM 33933

[0109] Pseudomonas aeruginosa DSM 33935

[0110] Pseudomonas oleovorans DSM 33936

[0111] Pseudomonas putida DSM 33937

[0112] Pseudomonas aeruginosa DSM 33938

[0113] Bakterien-Gemisch 3:

[0114] Nesterenkonia sp. DSM 108520

[0115] Nesterenkonia sp. DSM 108521

[0116] Alkalibacterium pelagium DSM 108522

[0117] Nesterenkonia massiliensis DSM 110679

[0118] Nesterenkonia sp. DSM 108519

[0119] Hefepilz-Gemi sch :

[0120] Pichia manshurica DSM 12249

[0121] Rhodotorula mucilaginosa DSM 12248

[0122] Candida boidinii DSM 13622 35

[0123] Candida albicans DSM 1386

[0124] The respective mixture was added as an inoculum to the respective sample at each inoculation with a concentration of 2% (v / w) fresh cell suspension in physiological saline (0.9% NaCl). The cell count of the added inoculum was 10 for bacterial mixtures 1 and 2. 9 / ml, 3 for the bacterial mixture and 10 for the yeast mixture 8 / ml, each consisting of equal parts of the individual bacterial and yeast strains.

[0125] The bacterial cell suspensions were prepared by culturing the individual bacteria for 24 to 48 hours at 30 °C in liquid culture on a shaker. Müller-Hinton liquid medium was used as the culture medium for bacteria from bacterial mixtures 1 and 2. Bacteria from bacterial mixture 3 were cultured in Müller-Hinton liquid medium, which had been previously adjusted to pH 9.5–9.7 with an alkaline buffer solution. After cultivation, the individual liquid cultures were centrifuged, and the cells were resuspended in physiological saline. To adjust the mixture to the desired cell count, the individual bacterial suspensions were diluted accordingly, if necessary, before being combined with saline. The cell count of the inoculation suspension was determined using chamber counting.

[0126] To prepare the cell suspension of the yeast mixtures, the yeast strains were cultivated on Sabouraud glucose agar for 48 hours at 25 °C, and the cell layer was washed off using physiological saline solution (0.9% NaCl). Further steps to adjust the cell count of the inoculation suspension were carried out analogously to the preparation of the bacterial cell suspensions.

[0127] When using bacterial mixtures 1 and 2, the samples were inoculated three times at weekly intervals with the respective cell suspensions (2% v / w). After each inoculation, the microbial contamination was assessed after 6 days of incubation of the inoculated samples at 30 °C.

[0128] When using bacterial mixture 3, the samples were inoculated once (2% v / w) and the microbial infestation was assessed directly after addition and after 7, 14, 21 and 28 days of incubation of the inoculated samples at 30 °C.

[0129] When using the yeast mixture, the samples were inoculated three times at two-week intervals with the respective cell suspensions (2% v / w). After each inoculation, the microbial contamination was assessed after 6 and 12 days of incubation at 30 °C. To evaluate microbial growth, an aliquot was taken from each sample after homogenization using a sterile plastic inoculation loop (10 g) and streaked evenly onto agar plates (bacterial mixtures 1 and 2 on tryptone-soy agar, bacterial mixture 3 on alkaline nutrient agar DSMZ 31, Sabouraud glucose agar for yeast). The streaked agar plates were then incubated for 48 hours (bacterial mixture 1 and 2 on tryptone-soy agar, bacterial mixture 3 on alkaline nutrient agar DSMZ 31, and Sabouraud glucose agar for yeast).

[0130] 1 and 2) or 5 to 7 days (bacterial mixture 3) at 30 °C, or 72 hours at 25 °C (yeast mixture). After incubation, the bacterial or yeast colonies grown on the agar plates were visually assessed and quantified according to the following scheme:

[0131] The results are shown in Tables 1 to 6:

[0132] Example 1 / Table 1: Inoculation 2% (w / v) with bacterial mixture 1, cell count 10 9 / ml

[0133] As can be seen from the test results shown in Table 1, concentrations as low as 0.05 wt% guanidine carbonate in adhesive 1, at a pH of 9.6 or higher, or concentrations as low as 0.25% guanidine hydrochloride at pH 9.3–9.4, lead to improved stabilization against microbial attack compared to the

[0134] Blank sample. Example 2 / Table 2:

[0135] Inoculation 2% (w / v) with yeast mixture, cell count 10 8 / ml As can be seen from the test results shown in Table 2, concentrations of guanidine carbonate from 0.05 wt% at pH 9.6 or higher or concentrations of guanidine hydrochloride from 0.25 wt% at pH 9.3 - 9.4 in the adhesive 1 lead to improved stabilization against microbial infestation compared to the blank sample.

[0136] Example 3 / Table 3:

[0137] Inoculation 2% (w / v) with bacterial mixture 1, cell count 10 9 / ml As can be seen from the test results shown in Table 3, concentrations of guanidine carbonate from 0.2 wt% at pH 9.8 or higher in the adhesive lead to improved stabilization against microbial infestation compared to the blank sample.

[0138] Example 4 / Table 4:

[0139] Inoculation 2% (w / v) with yeast mixture, cell count 10 8 / ml As can be seen from the test results shown in Table 4, concentrations of guanidine carbonate from 0.05 wt% at pH 9.6 or higher, or concentrations of guanidine hydrochloride from 0.25 wt% at pH 8.6–8.7, lead to improved stabilization against microbial attack in the adhesive compared to the blank sample. Example 5 / Table 5:

[0140] Inoculation 2% (w / v) with bacterial mixture 1, cell count 10 9 / ml As can be seen from the test results shown in Table 5, concentrations of 0.2 wt% guanidine carbonate at pH 9.7 or higher or concentrations of 0.25 wt% guanidine hydrochloride at pH 7.7 - 8.0 lead to improved stabilization against microbial attack in the adhesive compared to the blank sample.

[0141] Example 6 / Table 6:

[0142] Inoculation 2% (w / v) with yeast mixture, cell count 10 8 / ml As can be seen from the test results shown in Table 6, concentrations of 0.05 wt% guanidine carbonate at pH 9.4 or higher, or concentrations of 0.25 wt% guanidine hydrochloride at pH 7.7 - 8.0, lead to improved stabilization against microbial infestation in the adhesive compared to the blank sample.

[0143] Example 7 / Table 7:

[0144] Inoculation 2% (w / v) with bacterial mixture 2, cell count 10 9 / ml As can be seen from the test results shown in Table 7, concentrations of guanidine carbonate from 0.1 wt% at pH 8.0 or higher or concentrations of guanidine hydrochloride from 0.1 wt% at a pH of 7.6 - 7.7 lead to improved stabilization against microbial attack in the adhesive compared to the blank sample.

[0145] Example 8 / Table 8:

[0146] Inoculation 2% (w / v) with yeast mixture, cell count 10 8 / ml As can be seen from the test results shown in Table 8, concentrations of guanidine carbonate from 0.1 wt% at pH 8.0 or higher or concentrations of guanidine hydrochloride from 0.1 wt% at a pH of 7.6 - 7.7 lead to improved stabilization against microbial attack in the adhesive compared to the blank sample.

[0147] Example 9 / Table 9:

[0148] Inoculation 2% (w / v) with bacterial mixture 3, cell count 10 8 / ml As can be seen from the test results shown in Table 3, concentrations of guanidine carbonate from 0.05 wt% at pH 9.6 or higher in adhesives 1 and 2 lead to improved stabilization against microbial infestation compared to the blank sample.

Claims

Thor GmbH August 14, 2025 THO3 2024PC Patent claims 1. Aqueous adhesive composition containing at least the following components: (a) 1 to 95 wt.%, calculated as solid content, of a base component, containing: (al) at least one polymeric organic binder selected from acrylate, styrene, vinyl acetate, vin propionate and / or urethane homo- or copolymers or any mixture thereof, and / or (a2) at least one polysaccharide thickener selected from the group consisting of cellulose ethers, such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch ether, in particular modified amylose and / or amylopectin, guar ethers, dextrins and mixtures of these compounds, (b) water and (c) 0.03 to 1.4 wt.% guanidine and / or at least one salt of guanidine, wherein the wt. percentage refers to the guanidine content in the total aqueous adhesive composition, characterized in that the adhesive composition has a pH value in the range of pH 7.5 to 12.

0.

2. Adhesive composition according to claim 1, characterized in that the component (c) is contained in the adhesive composition in the range of 0.07 to 1.2 wt.%, wherein the wt. percentage refers to the guanidine content in the total composition.

3. Adhesive composition according to claim 1 or 2, characterized in that the at least one is a guanidine salt, guanidine hydrochloride and / or guanidine carbonate.

4. Adhesive composition according to one of claims 1 to 3, characterized in that the component (c) is contained in the range of 0.1 to 1.0 wt.%, wherein the wt. fraction refers to the guanidine content in the total composition.

5. Adhesive composition according to one of claims 1 to 4, characterized in that it has a water content in the range of 5 to 95 wt.%.

6. Adhesive composition according to one of claims 1 to 5, characterized in that it further comprises as component (d) one or more carbonate compound(s) selected from the group consisting of sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, ammonium bicarbonate and ammonium carbonate.

7. Adhesive composition according to any one of claims 1 to 6, characterized in that it comprises one or more preservative(s) selected from the group consisting of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one, N-butyl-1,2-benzisothiazolin-3-one, N-methyl-1,2-benzisothiazolin-3-one, octylisothiazolinone, Contains dichloroctylisothiazolinone, dithiobisbenzmethylamide, formaldehyde and formaldehyde cleavage, quaternary ammonium compounds, bronopol, dibromonitrilopropionamide, dibromodicyanobutane, iodopropynyl butylcarbamate, thiabendazole, sodium pyrithione, zinc pyrithione and o-phenylphenol in a total amount of less than 10 ppm, based on the composition.

8. Method for stabilizing an aqueous adhesive composition against microbial infestation, comprising the following process steps: (i) Providing an aqueous adhesive composition containing: (a) 1 to 95 wt.%, calculated as solid content, of a Basic component, containing: (al) at least one polymeric organic binder selected from acrylate, styrene, vinyl acetate, vin propionate and / or urethane homo- or copolymers, or any mixture thereof, and / or (a2) at least one polysaccharide thickener selected from the group consisting of cellulose ethers such as methylcellulose, carboxyalkylcellulose, in particular carboxymethylcellulose, hydroxyalkylcellulose, alkylhydroxyalkylcellulose, starch, in particular potato starch, starch ether, in particular modified amylose and / or amylopectin, guarethem, dextrins and mixtures of these compounds, (ii) Mixing at least one salt of guanidine with the aqueous adhesive composition and (iii) optionally adjusting the pH value, characterized in that the stabilized aqueous adhesive composition has a pH value in the range of pH 7.5 to 12.0, and further characterized in that the amount of the guanidine salt or guanidine salts is in the range of 0.03 to 1.4 wt.%, wherein the wt. fraction refers to the guanidine content in the total aqueous composition.

9. Method according to claim 8, characterized in that the at least one is a guanidine salt, guanidine hydrochloride and / or guanidine carbonate.

10. Method for producing an aqueous adhesive composition, comprising the following process steps: (i) Provide an aqueous adhesive composition, (ii) Mixing at least one salt of guanidine with the aqueous adhesive composition such that the amount of the guanidine salt, based on the content of guanidine in the total aqueous composition, is in the range of 0.03 to 1.4 wt.%, and (iii) optionally adjusting the pH value, characterized in that the aqueous adhesive composition produced has a pH value in the range of pH 7.5 to 12.0.

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