MXPA01007446A - Method for improving dye stability in colored acidic rinse-aid formulations - Google Patents

Abstract

A method for improving stability of a dye used in a colored aqueous acidic rinse aid composition to ambient and ultra-violet light radiation is disclosed. The method includes the step of adding a chelant to an acidic rinse aid composition. The chelant is present in an amount of at least 1 ppm by weight of the rinse aid composition.

Description

METHOD TO IMPROVE COLORING STABILITY IN AUXILIARY ACID FORMULATIONS WITH RINSE COLOR FIELD OF THE INVENTION The present invention relates to acid auxiliary formulations for rinsing that are used in automatic dishwashers. More particularly, the invention relates to a method for improving the stability of the dye used in an aqueous auxiliary rinse-aid composition for ultraviolet and ambient light radiation of an auxiliary rinse formulation for dishwashing machines.

BACKGROUND OF THE INVENTION It is well known to use rinsing aids in institutional and commercial dishwashing machines and also in automatic dishwashers for houses. In the automatic washing of the dishes, during the rinse cycle, a final rinse of drinking water serves to move the final pre-rinse water and its auxiliary detergents and dirt residues. Auxiliary rinsing formulations are aqueous solutions containing a non-ionic low foaming surfactant. During a rinse cycle, the rinse aid is injected into the final potable water that is rinsed at a concentration of approximately 100 to 500 ppm.

The surfactant in the rinse water decreases the surface tension of the rinse water and improves the wetting action of the rinse water. The inventors of the present invention have previously discovered that it is possible to formulate an aqueous rinse aid containing a low foaming nonionic surfactant and a neutralized, partially neutralized, or unneutralized low molecular weight polyacrylate polymer without the use of a compatible high molecular weight polymer or a surfactant coagent with high dark point, in this way an acidic, aqueous and stable auxiliary rinse dispersion is provided which reduces stains and film formation since the coating and drainage action is improved . However, one of the main problems associated with the stable acidic auxiliary rinsing dispersion is that when a dye is added in the composition to impart a pleasant color, especially a typical blue or green dye, such as a blue dye # 1 FD & For example, there is a tendency for such rinse aid compositions to change color upon exposure to the environment and ultraviolet light, for example sunlight. Frequently, if not unavoidable, acidic rinse aids will be subject to ultraviolet light (eg sunlight) repeatedly and for prolonged periods before being used by the consumer. The formulations of the rinse aids of ordinary automatic dishwashers (ADW) are specifically adjusted to a color that has been tested is aesthetically pleasing to consumers. Any change in color, the target formulation, especially when using a transparent or clear bottle or other packaging container, can negatively impact the consumer's perception of the quality of the product. Typically, in the past, rinsing color auxiliary compositions have been formulated with or near a neutral pH, since in the past this was generally understood as that the nonacid auxiliary rinsing compositions would not reduce the colorant stability for the ultraviolet and environmental light radiation. The inventors of the present invention have focused on this stability of the colorant in the present invention and provide an effective solution to the problem. Prior to the present invention, there was no previously known method or composition that would address this problem of dye stability in acidic rinse aid compositions. Accordingly, it is desirable to have an acidic rinse-aid product that is not significantly altered by ultraviolet light. In addition, despite the above-mentioned descriptions in the art, it is desirable to have an acidic rinse aid product that has superior performance in addition to good appearance when packaged. It is very desirable that the good appearance when packaging (for example, color) is maintained until the consumer has discarded the product. The present invention overcomes the problems set forth above.

TECHNICAL BACKGROUND The patent of E.U.A. No. 5,254,282, issued October 19, 1993 to Fusiak, describes acid formulations for removing paints that are stabilized against color formation by inclusion of a chelating agent; and the patent of E.U.A. No. 5,206,006, issued April 27, 1993 to Frontini et al., Discloses a composition for detecting hydrogen peroxide developed in a solution, which contains a chelating agent, important portions of both of which are incorporated herein by reference.

BRIEF DESCRIPTION OF THE INVENTION The invention covers the above needs by providing a method and composition for improving the stability of a dye used in an acidic auxiliary composition with aqueous color for rinsing for ultraviolet and ambient light radiation. In one aspect of the present invention, the method for improving the stability of a dye that is used in an aqueous acidic auxiliary composition for rinsing for ultraviolet and ambient light radiation and includes the step of adding a chelator to an auxiliary composition rinsing acid. The chelator is present in an amount of at least 1 ppm by weight of the acidic rinse aid composition.

In another aspect of the present invention, an acid color rinse aid composition that exhibits improved stability of a colorant used for ultraviolet and ambient light radiation includes a low foaming nonionic surfactant present on a scale of 2. % to 80% by weight of the auxiliary rinsing composition. The composition also includes a hydrotrope present on a scale of about 0.5% to 20% by weight of an auxiliary rinsing composition. The composition further includes a polyacrylate polymer present on a scale from about 0.1% to 15% by weight of the rinse aid composition. The polymer has a weight average molecular weight on a scale of about 1000 to 50,000. The composition includes a chelator. The chelator is present in an amount of at least 1 ppm by weight of the auxiliary rinse composition.

DETAILED DESCRIPTION OF THE INVENTION In the preferred embodiment of the present invention, the method includes the step of adding a chelator to an acidic rinse aid composition. The chelator is desirably present in an amount of at least 1 ppm, preferably at least 50 ppm, more preferably at least 100 ppm and still more preferably at least 150 ppm by weight of the rinse aid composition.

Chelators In the preferred embodiment, the acidic rinse aid composition includes chelators that are selected from the group consisting of aminocarboxylates, aminophosphonates, polyfunctionally substituted aromatic chelators, and mixtures thereof. Other useful chelating agents include manganese and / or iron chelators. Useful aminocarboxylates are optional chelators including ethylenediaminetetracetates, N-hydroxyethylenediamineathacetates, nitrilotriacetates, ethylenediamine tetraproprionates, triethylenetetramine hexacetates, diethylenetriaminepentacetates, and ethanoldiglicines, alkali metal, ammonium and substituted ammonium salts therein and mixtures therein. Polyfunctionally substituted aromatic chelators include dihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene, and ethylenediamine disuccinate ("EDDS"). In the preferred embodiment, the chelator is selected from the group consisting of ethylenediaminetetraacetic acid carboxylate, diethylenetriaminepentaacetic acid carboxylate, and mixtures thereof. In another preferred embodiment, the chelating agents are selected from the group consisting of polyphosphonate, ethylenediaminetetraacetic acid carboxylate (EDTA) and diethylenetriaminepentaacetic acid carboxylate (DTPA). More preferably the chelator is ethylenetriaminepentaphosphoric acid.

Dyes In the preferred embodiment of the present invention, the dye is selected from the group consisting of Pontamine Blue (copper phthalocyanine dye), and Liquitant Patent Blue (polymeric dye) and Blue # 1 FD &; C (having the molecular formula C37H34N2Na2? 9S3), and mixtures thereof. Preferably, the colorant has a color that is selected from the group consisting of blue, green, or mixtures thereof. It has been found that the blue and green dyes normally used in auxiliary rinse formulations, such as # 1 FD &C, are unstable for ultraviolet light under acid conditions unless the rinse aid composition is formulated with a chelator in accordance to the present invention. It has been discovered that even so-called "stable acid" dyes, such as Acid Blue 80, fade rapidly when used with acid rinse aids, ie, the dye has no color after it was exposed for 1 to 2 days under the ultraviolet light radiation, unless the rinse aid is formulated according to the present invention, with a chelator. Desirably, the dyes are added in an amount on a scale of about 0.25% of a 1% solution in water to about 0.5% of a 1% solution in water.

Coloring-chelating systems In the preferred embodiment the dye is selected from the group consisting of copper phthalocyanine dye, colors # 1 FD &C, polymeric dyes and mixtures thereof and the chelator is selected from the group consisting of aminocarboxylates, aminophosphonates, polyfunctionally substituted aromatic chelators, and mixtures thereof. It has been found that these "dye-chelator" systems optimally provide the color stability in the dye most effective for ultraviolet and ambient light radiation, when said dyes are used in acid rinse aids. More preferred chelators are selected from phosphonate-ethylenediaminetetraacetic acid carboxylate (EDTA) and diethylenetriaminepentaacetic acid carboxylate (DTPA) in combination with the most preferred dyes that are selected from blue dyes such as Pontamine Blue (copper phthalocyanine dye) and Liquitant Patent Blue (polymeric dye) and # 1 FD &C (e.g. Blue # 1 FD &C having the molecular formula C37H3 N2Na2? 9S3). These dye-chelator systems discovered by the inventors, when formulated in an auxiliary aqueous rinse dispersion, form systems with ultraviolet and ambient light resistance and stable to color. The especially preferred dye-chelator systems discovered by the inventors are listed below: Liquitant Patent Blue in combination with CW base; # 1 FD &C in combination with CW base; Pontamine Blue in combination with CW base; Liquitant Patent Blue in combination with DTPA; # 1 FD &C in combination with DTPA; and Liquitant Patent Blue in combination with DTPA.

Carboxylic Acids In the preferred embodiment, the stability of the dye is further increased in the presence of carboxylic acids. Especially preferred are polycarboxylic acids such as Sokolan PA13PN manufactured by BASF, Acusol 480, and Acusol 480N, both manufactured by Rohm & Hass. These polycarboxylic acids provide multiple benefits, as they help to stabilize the colorant and provide performance benefits of film formation in the automatic dishwasher rinse cycle. It is desired that the polycarboxylic acid be present in an amount on a scale of about 0.25% to 10% by weight of the acidic rinse aid compositions, and preferably in an amount on a scale of about 1% to 6% by weight. weight. In another embodiment of the present invention, the rinsing color acid auxiliary composition exhibits improved stability of a colorant used therein for ultraviolet and ambient light radiation including a desirable low foaming nonionic surfactant. present on a scale of about 2% to 80% by weight of the rinse aid composition. The composition also includes a desirable hydrotrope present on a scale of about 0.5% to 20% by weight of the rinse aid composition. The composition also includes a desirable polyacrylate polymer present on a scale from about 0.1% to 15% by weight of the rinse aid composition. The polymer has a weight average molecular weight on a scale of about 1000 to 50,000. The composition also includes a chelator. The chelator is present in an amount of at least 1 ppm by weight of the auxiliary rinse composition.

Low foaming nonionic surfactant The nonionic surfactants useful in the auxiliary aqueous rinse aid dispersion may be any known low foaming nonionic surfactant which is used in dishwasher applications. Suitable common nonionic surfactants include the following commercially available materials: Triton R ™ CF-10 (a polyether alkylaryl) and Triton DF-16 (a modified polyalkoxylate alcohol) manufactured by Rohm and Hass Company; Plurafac LF404 ™, Plurafac LF400 ™ (mixed linear alcohol alkoxylates) and Pluronic R ™ L-62 (a polyoxyethylene-polyoxypropylene blocking copolymer), all manufactured by BASF Wyandotte Corporation, and BASF RA30 surfactant manufactured by BASF Corporation. The auxiliary wiping formulation of the invention may contain one or more mixtures of said low-foaming nonionic surfactants. Essentially any nonionic surfactant useful for detersive purposes can be included in the rinse aid compositions. The non-limiting classes by way of example of the useful nonionic surfactants are listed below. (i) Non-ionic polyhydroxy fatty acid amide surfactants The polyhydroxy fatty acid amides suitable for use herein are those having the structural formula R2CONR1Z wherein: R1 is H, C? -C4 hydrocarbyl, 2-hydroxyethyl? , 2-hydroxypropyl, or a mixture thereof, preferably C 1 -C 4 alkyl, more preferably Ci or C 2 alkyl, more preferably C 1 alkyl (ie methyl); and R2 is a C5-C31 hydroxycarbyl preferably alkenyl or straight chain C5-C19 alkyl, more preferably straight chain alkenyl or C9-C17 alkyl, even more preferably straight chain C11-C17 alkenyl or alkyl or mixtures thereof; and Z is a polyhydroxyhydrocarbyl having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z will preferably be derived from a reducing sugar in a reductive amination reaction; more preferably Z is glycityl. (ii) Non-ionic condensates of alkylphenols The condensates of polybutylene oxide, polypropylene and polyethylene of alkylphenols are suitable for use herein. In general, polyethylene oxide condensates are preferred. These compounds include the condensation products of alkylphenols having an alkyl group containing about 6 to 18 carbon atoms in each straight or branched chain configuration with the alkylene oxide. (ii) ethoxylated nonionic alcohol surfactant The alkylatoxyl condensation products of aliphatic alcohols with about 1 to 25 moles of ethylene oxide are suitable for use herein. The alkyl chain of aliphatic alcohol may be straight or branched, primary or secondary, and generally contains from 6 to 22 carbon atoms. Particularly preferred alcohol condensation products have an alkyl group containing from 8 to 22 carbon atoms with from about 2 to 10 moles of ethylene oxide per mole of alcohol. (iv) Propoxylated / non-ionic ethoxylated fatty alcohol surfactant The ethoxylated Cß-C-iß fatty alcohols and mixed C6-C18 propoxylated / ethoxylated fatty alcohols are highly preferred surfactants which are used herein, particularly where they are soluble in water. Water. Preferably, the ethoxylated fatty alcohols are ethoxylated C-io-C-iß fatty alcohols with an ethoxylation degree of from 3 to 50, more preferably these are C12-C18 ethoxylated fatty alcohols with an ethoxylation degree of from 3 to 40. Preferably, the mixed propoxylated / ethoxylated fatty alcohols have a long alkyl chain of 10 to 18 carbon atoms, a degree of ethoxylation of 3 to 30 and a degree of propoxylation of 1 to 10. (v) Non-ionic EO / PO condensates with propylene glycol The condensation products of ethylene oxide with a hydrophobic base formed by the condensation of propylene oxide with propylene glycol are suitable for use herein. The hydrophobic portion of these compounds preferably has a molecular weight of about 1500 to 1800 and exhibits an insolubility in water. Examples of the compound of this type include certain commercially available surfactants of Pluronic ™ marketed by BASF. (vi) Nonionic EO condensation products with propylene oxide / ethylene diamine adducts The condensation products of ethylene oxide with the products resulting from the reaction of propylene oxide and ethylene diamine are suitable for use herein. The hydrophobic portion of these products consists of the reaction product of ethylenediamine and excess propylene oxide, and generally has a molecular weight of about 2500 to 3000. Examples of this type of nonionic surfactants include certain compounds commercially available from Tetronic ™. , marketed by BASF. (vii) Nonionic Alipyl Polysaccharide Surfactants The alkyl polysaccharides suitable for use herein are described in the U.S.A. No. 4, 565, 647, Filling, issued January 21, 1986, having a hydrophobic group containing from about 6 to 30 carbon atoms, preferably from 10 to 16 carbon atoms and a polysaccharide, for example a hydrophilic group, polyglycoside of approximately 1.3 to 2.7 units of saccharide. Any reducing saccharide containing 5 or 6 carbon atoms can be used, for example portions of glucose, galactose and galactosyl can be replaced by the glucosyl portions (optionally the hydrophobic group is added to the 2-, 3-, 4- positions, etc., in this way giving a glucose or galactose opposite to a glucoside or galactoside). The intersaccharide linkages can be for example between a position of the additional saccharide unit and positions 2-, 3-, 4-, and / or 6- in the above saccharide units. Preferred alkyl polyglycosides have the formula: R2O (CnH2nO) t (glycosyl)? wherein R2 are selected from the group consisting of alkyl, alkylphenyl, hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof wherein the alkyl groups contain from 10 to 18, preferably from 12 to 14 carbon atoms; n is 2 or 3, preferably from about 1.3 to 3, more preferably from 1.3 to 2.7. The glycosyl is preferably derived from glucose. (viii) Nonionic Fatty Acid Amide Surfactants The fatty acid amide surfactants suitable for use herein are those having the formula: wherein R6 is an alkyl group containing from 7 to 21, preferably from 9 to 17 carbon atoms and each R7 is selected from the group consisting of hydrogen, CrC2 alkyl, C1-C4 hydroxyalkyl, and ~ (C2H4O) xH, wherein x is on the scale of 1 to 3. The hydrotrope useful in the present auxiliary rinse dispersion is selected from the group consisting of sodium eumeno sulfonate, sodium xylene sulfonate, sodium toluenesulfonate, sodium dioctyl sulfosuccinate, sulfonated alkylnaphthalene and sodium dihexyl sulfosuccinate. Preferably, the hydrotrope is sodium eumeno sulfonate.

Polyacrylate Polymer The low molecular weight polyacrylate polymer useful in the present auxiliary rinse aid dispersion is selected from the group consisting of polyacrylate homopolymer, polyacrylate copolymer, polyacrylate terpolymer, and mixtures thereof. Preferably, the polyacrylate polymer is a partially neutralized, non-neutralized polyacrylate polymer having a pH on the scale of about 2.0 to 4.0. In the preferred embodiment, the polyacrylate polymer is desirable at least about 75% unneutralized. Alternatively, the polyacrylate polymer is not neutralized. Still alternatively, it can be used is a neutralized polyacrylate polymer, which is more than 25% neutralized, but an acid must be added in an amount sufficient to bring the pH value of the resulting rinse aid dispersion within a scale of about 2 to 6. Typically, the polyacrylate polymer is a homopolymer of methacrylic or acrylic acid, or a copolymer formed of at least about 50% by weight of acrylic acid. The polyacrylate polymer is a low molecular weight polymer or its alkali metal or its ammonium salt having a weight average molecular weight in the range of about 1,000 to 40,000.

Acid When an acid is added to the auxiliary rinsing dispersion, any acid can be used even though the organic acids are more desirable and the preferred organic acid is citric acid. It has been found that even in the absence of a high molecular weight polymer compatibility, but with the addition of a hydrotrope and under acidic conditions, the stable rinse aid dispersion is not separated in faces when stored for a reasonable time or under conditions of actual use and allows each component to effectively reduce stains and film removal and improve the coating action without interfering with the foaming and anti-foaming action of the surfactant. In the preferred embodiment, the auxiliary rinse formulation of the invention is an aqueous dispersion with a pH of about 2 to 6. Preferably, the pH is in the range of about 3 to 5. The auxiliary rinse dispersion of the present invention is preferably prepared by stirring the desired amount of the surfactant in an aqueous solution of the neutralized or only partially neutralized polyacrylic acid (not more than 25% is neutralized) of low molecular weight by gradual addition of the hydrotrope and if necessary , citric acid so that the dispersion is within the desired pH scale. The formulation may also contain other additives that include sequestrants such as NTA, EDTA, or sodium citrate and water miscible solvents such as ethanol, isopropanol and propylene glycol. Ethanol is the preferred solvent, on a desirable present scale of about 0.1% to 10% by weight of the auxiliary rinse dispersion and preferably on a scale of about 2% to 8% by weight.

Hydrotrope In the preferred embodiment, the hydrotrope is selected from the group consisting of sodium eumeno sulfonate, sodium xylene sulfonate, sodium toluenesulfonate, sodium sulfosuccinate dioctyl, alkylnaphthalene sulfonate and sodium sulfonsuccinate dihexyl. Preferably, the hydrotrope is sodium eumenium sulfonate and the partially neutralized polyacrylate polymer is a polyacrylate copolymer that is approximately 20% neutralized. In the preferred embodiment, the stable aqueous rinse aid dispersion is essentially free of a high molecular weight compatibility polymer and is also free of an additional nonionic surfactant having a dark point of at least 70 ° C. The following examples are intended to illustrate the invention.

EXAMPLE 1 An auxiliary dispersion for rinsing according to the present invention is made as follows, from the following compositions, in percent by weight: Low-foaming non-ionic surfactant 20.0% Sodium eumenium sulfonate hydrophobic 7.0% Copolymer of polyacrylate (20% neutralized) 4.5% Ethanol 6.0% Chelator (DTPA) 0.015% Liquitant Patent Blue 0.25% Water 62.235% This dye has a radiation stability of ultraviolet and ambient light and its color does not change after exposure to radiation. Ultraviolet light for 1 to 2 days.

EXAMPLE 2 Another auxiliary rinsing dispersion according to the present invention is prepared as follows, from the following composition, in percent by weight: Low-foaming non-ionic surfactant 35.0% Sodium eumeno sulfonate hydrotrope 4.0% Copolymer of polyacrylate (20% neutralized) 4.0% Citric acid 1.6% Ethanol 6.0% Chelator (polyphosphonate) 0.015% Blue # 1 FD &C 0.25% Water 49.135% This dye has ultraviolet and ambient light radiation stability and its color does not change after be exposed to ultraviolet light radiation for 1 to 2 days.

EXAMPLE 3 Another auxiliary rinsing dispersion according to the present invention is prepared as follows, from the following composition, in percent by weight: Low-foaming nonionic surfactant 12.0% Sodium eumeno sulfonate hydrotrope 4.0% Copolymer of polyacrylate (20% neutralized) 1.0% Citric acid 1.6% Ethanol 5.0% Chelator (polyphosphonate) 0.015% Blue # 1 FD &C 0.25% Water 76.135% This dye has a radiation stability of ultraviolet and ambient light and its color does not change after of exposure to ultraviolet light radiation for 1 to 2 days. The above auxiliary rinsing formulations were prepared by the following procedures: appropriate quantities of: a low foaming nonionic surfactant (Plurafac LF 404 ™), 45% hydrotrope of active sodium eumeno sulfonate (45% active SCS), 50% active polyacrylate copolymer (Acusol 480 ™, manufactured by Rohm &Haas), 50% ethanol of active citric acid and deionized water are added to a beaker and agitated sequentially. A chelator is also added in an amount of 0.015% by weight (150 ppm by weight) and a dye as indicated. The resulting mixture obtained is a single-phase acid dispersion in blue or green color and which is also stable, without phase separation occurring after the resulting mixture is kept unchanged in a closed container for a period of 2 weeks at a time. temperature of 50 ° C. In addition, the resulting mixture exhibits no more than about 30% discoloration when exposed to ambient light for 6 months, and no more than about 30% discoloration when exposed to ultraviolet light for 2 days. Accordingly, having described the invention in detail, it will be obvious to those skilled in the art that various changes can be made without departing from the scope of the present invention and the invention will not be considered as limiting for what is described in the specification.

Claims (9)

NOVELTY OF THE INVENTION CLAIMS

1. - A method to improve the stability of a dye used in an auxiliary composition with aqueous color for rinsing for the radiation of ultraviolet and environmental light characterized by the steps of: adding a chelp + gdor to an auxiliary rinsing acid composition, said chelator it is present in an amount of at least 1 ppm by weight in said auxiliary rinse composition.

2. The method according to claim 1, further characterized in that said chelator is present in an amount of at least 50 ppm by weight of said auxiliary rinsing composition.

3. The method according to claims 1 to 2, further characterized in that said chelator is selected from the group consisting of aminocarboxylates, aminophosphonates, polyfunctionally substituted aromatic chelators and mixtures thereof.

4. The method according to claims 1 to 3, further characterized in that said chelator is selected from the group consisting of ethylenediaminetetraacetic acid carboxylate, diethylenetriaminepentaacetic acid carboxylate, and mixtures thereof.

5. - The method according to claims 1 to 4, further characterized in that said chelator is ethylene trinophobic phosphoric acid.

6. The method according to claims 1 to 5, further characterized in that said dye is selected from the group consisting of copper phthalocyanine dye, color # 1 FD &C, polymer dyes and mixtures thereof.

7. The method according to claims 1 to 6, further characterized in that said dye is selected from the group consisting of copper phthalocyanine dye, color # 1 FD &C, polymer dyes and mixtures of the mimes, and said chelator is selected from the group consisting of aminocarboxylates, aminophosphonates, polyfunctionally substituted aromatic chelators, and mixtures thereof.

8. An acid auxiliary composition with color for rinsing exhibiting an improved stability of a dye used therein for ultraviolet and ambient light radiation, characterized by: a non-ionic low foaming surfactant present on a scale of about 2% to 80% by weight of said auxiliary rinsing composition; a hydrotrope present on a scale of about 0.5% to 20% by weight of said auxiliary rinsing composition; a polyacrylate polymer present on a scale of about 0.1% to 15% by weight of said auxiliary rinse aid composition, said polymer having a weight-average molecular weight on a scale of about 1,000 to 50,000; and a chelator, said chelator is present in an amount of about 1 ppm by weight of said auxiliary rinse composition.

9. The rinse aid auxiliary composition according to claim 8, further characterized in that said rinse aid has a pH on a scale of about 2 to 7. The auxiliary rinse aid composition according to claim 8, further characterized in that it includes an acid present on a scale of about 0.1% to 20% by weight of said auxiliary rinse composition.