DE3788075T2 - Stable liquid detergent composition containing a hydrophobic optical brightener. - Google Patents

Abstract

Stable isotropic liquid laundry detergents containing a surfactant and a hydrophobic brightener to reduce brightener staining of fabrics. Suitable species of preferred hydrophobic brighteners include disulfonated tetra-anilino naphthotriazolyl stilbene brighteners.

Description

The present invention relates to stable, preferably single phase, isotropic, liquid laundry detergents containing a particular hydrophobic bissulfonate brightener which reduces or prevents fabric staining by the softener while maintaining an exceptional level of whiteness. Particularly preferred are disulfonated tetra-anilinonaphthotriazolylstilbene brighteners. In some embodiments, the hydrophobic brighteners herein can be combined with various amounts of conventional liquid detergent brighteners to further improve and optimize the overall appearance of the fabric. In the event that such blended brighteners are employed, the hydrophobic brightener herein should constitute at least 40% of the total brightener to provide the desirable performance benefits.

Optical brighteners, also known as fluorescent whitening agents, are commonly used in laundry detergents. The brighteners deposit on the fabrics where they absorb ultraviolet radiant energy and re-emit it as a blue dense. This reduces or prevents any yellowing of the fabrics and gives them a brighter appearance. However, undesirable staining from the brightener can occur when liquid detergents come into direct contact with cotton-containing fabrics. The present invention reduces or prevents such staining while maintaining an acceptable level of fabric whiteness.

State of the art

Considerable effort has been directed toward the use of asymmetric monosulfonated naphthotriazolylstilbene (MSB) brighteners to overcome and reduce undesirable staining by the brightener. Representative of these art endeavors are a number of published patents.

British Patent Specification 2 028 365, Gray, published on 5 March 1980, contains builder-containing liquid Detergents containing anionic surfactants and one or more brighteners, including MSB.

U.S. Patent No. 3,812,041, Inamorato, issued May 21, 1974, describes builder-free liquid detergents containing nonionic surfactants and anionic surfactants in a weight ratio of nonionic surfactants to anionic surfactants of at least 1. Optional brighteners may include the MSB type.

In U.S. Patent No. 3,959,157, Inamorato, issued May 25, 1976, liquid detergents are disclosed which may contain nonionic surfactants, quaternary ammonium softeners and optional brighteners, also including MSB.

U.S. Patent No. 4,430,236, Franks, issued February 7, 1984, describes liquid detergents containing nonionic surfactants, optional anionic surfactants, hydrogen peroxide, brighteners, and preferably quaternary ammonium softening compounds. MSB brighteners are specifically mentioned as being useful.

Japanese patent application J 74-017004, published on April 26, 1977, describes liquid detergents containing MSB, which is said to be stable to light.

In German patent application 25 43 998, published on April 7, 1977, clear, liquid detergents are described which contain certain diphenyldistyryl brighteners. Examples 1 and 2 relate to liquid detergents which contain mixtures of MSB and disulfonated brighteners.

German patent application 26 09 752, published on 22 September 1977, relates to improving the low temperature stability of detergent compositions containing brighteners and does not distinguish between brighteners of different hydrophobicity or solubility.

European application 85200988.5, filed on June 21, 1985, teaches the use of MSB, optionally in combination with conventional dianilino-dimorpholino-distilbene brighteners with a view to reducing unwanted brightener deposits.

Although these prior art attempts can provide significant improvements over conventional brighteners in terms of reducing staining, their wash performance, e.g., maintaining whiteness, is no better than that achieved with conventional disulfonate brighteners.

FR-A-2 130 106, published on November 3, 1972, contains a composition and a process for solubilizing water-insoluble brighteners. It describes liquid detergents containing anionic and/or non-ionic surfactants, organic builders, hydrotropes, optical brighteners, ethylene glycol ethers and/or dimethyl sulfoxide.

It is a primary object of this invention to formulate concentrated liquid heavy-duty detergent compositions containing brighteners which do not exhibit the disadvantages of brightener staining during use, while providing at least equivalent whiteness maintenance compared to conventional detergent brighteners.

The above and other objectives can now be achieved by the incorporation of disulfonated brighteners in liquid duty detergents, which brighteners are more hydrophobic than current disulfonated brighteners.

Summary of the invention

The present invention relates to stable, isotropic heavy-duty detergent compositions comprising, by weight,

(a) 3% to 60% of a surfactant selected from anionic and nonionic surfactants and mixtures thereof; and

(b) 0.01% to 1% of a hydrophobic disulfonated brightener which represents at least 40% of the total brightener in the composition, which hydrophobic brightener has the formula:

wherein R₁, R₂, R₃ and R₄ are tetra-anilino, tetra-piperazino, tetra-cyclohexylamino, dianilino-dipiperazino and dianilino-dicyclohexylamino; and

(c) a solvent selected from lower aliphatic alcohols having 2 to 6 carbon atoms and 1 to 3 hydroxyl groups.

Detailed description of the invention

The compositions of the present invention comprise 3% to 60% of a surfactant, 0.01% to 1% of a hydrophobic brightener, and a lower aliphatic alcohol as a solvent. The essential ingredients of the invention as well as the optional components which may be desirably incorporated into the compositions of this invention are described hereinafter.

Throughout the description, percentages refer to "percent by weight" unless otherwise stated.

The hydrophobic brightener herein has the formula:

wherein R₁, R₂₁, R₃ and R₄ are selected from tetra-anilino, tetra-piperazino, tetra-cyclohexylamino, dianilino-dipiperazino and dianilino-dicyclohexylamino groups.

For reasons of reducing the coloration by the brightener, the tetraanilino derivatives of the following formula: 4,4'-bis(4-anilino-6-anilino-s-triazin-2-yl)amino)-2,2'-stilbenedisulfonic acid sodium salt (A) are most preferred. A preferred Brightener system in the context of this invention contains at least 40% (based on the total amount of detergent brightener) of the particular hydrophobic brightener referred to hereinabove in combination with a conventional detergent brightener, e.g., a disulfonated dianiline dimorpholinostilbene brightener.

Conventional detergent brighteners for use in conjunction with the hydrophobic species described hereinabove include conventional detergent brighteners including:

4-(2H-naphtho(1,2-d)triazol-2-yl)-2-stilbenesulfonic acid sodium salt; (i)

4,4'-Bis((4-anilino-6-(N-2-hydroxyethyl-N-methylamino)-s-triazin-2-yl)amino)-2,2'-stilbenedisulfonic acid disodium salt; (ii)

4,4'-Bis(4-anilino-6-morpholino-s-triazin-2-yl)amino)-2,2'-stilbenedisulfonic acid sodium salt; (iii)

2,2-(4,4'-biphenylenedivinylene)dibenzenesulfonic acid disodium salt; (ivi)

4,4'-bis(4-phenyl-2H-1,2,3-triazol-2-yl) disodium salt; (vi)

4,4'-Bis(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino)-2- stilbenesulfonate sodium salt (vii).

Although the hydrophobic brightener should constitute at least 40% of the total brightener, it is to be understood that the amount may vary depending on the particular nature of the conventional brightener. For example, the hydrophobic tetraanilino brighteners may desirably constitute 55% to 80% of the total brightener when the conventional brightener is formed from (i).

The surfactant can be constituted by anionic and nonionic surfactants and mixtures thereof. The surfactant is usually from 3% to 60%, preferably from 10% to 50%. Suitable anionic surfactants are described in U.S. Patent No. 4,285,841, Barrat et al., issued August 25, 1981, and U.S. Patent No. 3,929,678, Laughlin et al., issued December 30, 1975, both of which are incorporated herein by reference.

Useful anionic surfactants include the water-soluble salts, particularly the alkali metal, ammonium and alkylolammonium salts (e.g. monoethanolammonium or triethanolammonium salts) of organic sulfuric acid reaction products which have in their molecular structure an alkyl group having 10 to 20 carbon atoms and a sulfonic acid or sulfuric acid ester group. (The term "alkyl" includes the alkyl portion of aryl groups.) Examples of this group of synthetic surfactants are the alkyl sulfates, particularly those obtained by sulfating the higher alcohols (C8-C18 carbon atoms) such as are prepared by reducing the glycerides of tallow or coconut oil; and the alkylbenzenesulfonates wherein the alkyl group contains 9 to 15 carbon atoms in straight chain or branched chain configuration, e.g. B. those of the type described in U.S. Patent Nos. 2,220,099 and 2,477,383. Particularly valuable are linear straight-chain alkylbenzenesulfonates in which the average number of carbon atoms in the alkyl group is about 11 to 14.

Other anionic surfactants herein are the water-soluble salts of paraffin sulfonates having 8 to 24 (preferably 12 to 18) carbon atoms; alkyl glyceryl ether glyceryl ether sulfonates, particularly those ethers of C8-18 alcohols (e.g. those obtained from tallow and coconut oil); alkylphenol ethylene oxide ether sulfates having 1 to 4 ethylene oxide units per molecule and 10 to 20 carbon atoms in the alkyl group.

Other useful anionic surfactants herein include the water-soluble salts of esters of alpha-sulfonated fatty acids having from 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxyalkane-1-sulfonic acids having from 2 to 9 carbon atoms in the acyl group and from 9 to 23 carbon atoms in the alkane moiety; water-soluble salts of olefin sulfonates having from 12 to 24 carbon atoms; and beta-alkyloxyalkane sulfonates having from 1 to 3 carbon atoms in the alkyl group and from 8 to 20 carbon atoms in the alkane moiety.

Preferred anionic surfactants are the C₁₀-C₁₈ alkyl sulfates with an average of 0 to 4 ethylene oxide units per mole of alkyl sulfate, linear C₁₁-C₁₃ alkylbenzenesulfonates and mixtures thereof.

The nonionic surfactant can be represented by known species which are extremely well known in the art and many of which have found widespread commercial acceptance. Suitable ethoxylated nonionic surfactants for use herein have the formula R¹(OC₂H₄)nOH, wherein R¹ is a C₁₀-C₁₆ alkyl group or a C₈-C₁₂ alkylphenyl group, n is from 3 to 9, which nonionic surfactant has an HLB (hydrophilic-lipophilic balance) of from 10 to 13. These surfactants are more fully described in U.S. Patent Nos. 4,285,841, Barrat et al., issued August 25, 1981; and 4,284,532, Leikhim et al., issued August 18, 1981, both of which are incorporated herein by reference. Particularly preferred are condensation products of C12-C15 alcohols with 3 to 8 moles of ethylene oxide per mole of alcohol, e.g., a C12-C13 alcohol condensed with 6.5 moles of ethylene oxide per mole of alcohol.

A well-known nonionic agent for use herein can be represented by amine oxide surfactants such as the C12-C16 alkyl dimethyl amine oxides.

Amine oxide surfactants are often used at levels of 0.5% to 4% in conjunction with conventional ethoxylated nonionics.

In such non-ionic systems, the weight ratio of amine oxide to non-ionic ethoxylate is often in the range of 1:8 to 1:50.

Although the compositions of the invention may be based on a combination of exclusively anionic surfactants or exclusively nonionic surfactants, it is often desirable to use anionic and nonionic surfactants in a weight ratio of 1:1 to 3:1. Expressed as a weight ratio, the nonionic surfactant may be represented by a mixture of a nonionic ethoxylate-based surfactant and an amine oxide-based surfactant.

The compositions of the present invention may contain, in addition to the essential surfactants described hereinabove, as optional ingredients, other synthetic surfactants known in the art, such as cationic, zwitterionic and ampholytic surfactants. These optional surfactants may be used in additive amounts and should typically constitute less than 40% of the total surfactant in the formulation. Suitable examples of these optional surfactants are described in U.S. Patent Nos. 4,285,841 and 3,929,678.

The compositions according to the invention are aqueous compositions and contain, depending on the respective amounts of essential ingredients and the possible amounts of optional ingredients, an amount of water to reach 100%. In some preferred embodiments of liquid heavy-duty detergents according to the invention, the amount of water can be in the range of 60% to 20%.

The compositions of this invention often have a pH, measured in a 1% aqueous solution at 20°C, in the neutral to mildly alkaline range, i.e. from 6.5 to 9.

In addition to the essential ingredients described hereinabove, the compositions of the invention often contain a number of optional ingredients which are used in conventional amounts because of their known functionality. These optional ingredients generally enhance and promote the detergent performance of the claimed compositions. Examples of such optional ingredients include perfumes, dyes, opacifiers, germicides, antioxidants, foam regulators including silicones and hydrogenated fatty acids, builders including tartrate monosuccinic acid, sodium tripolyphosphate and sodium pyrophosphate, citric acid, fully hydrated zeolite having a particle diameter in the range of 1 to 10 µm; and alkenyl succinates having 10 to 16 carbon atoms in the alkenyl moiety. Other optional components include soil release agents such as polyethylene glycol terephthalate, performance enhancers, e.g. tetraethylene pentamine having 15 to 19 EO, corrosion inhibitors such as Aminosilanes, enzymes, cationic surfactants, fabric softening agents such as quaternary ammonium salts and bentonite clays, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, fatty acids, alkylenepolyaminopolyalkylenephosphonic acids, enzyme stabilizing systems and liquid matrix components including water and suitable solvents.

Suitable saturated or unsaturated fatty acids have 10 to 18 carbon atoms in the alkyl chain. Unsaturated species having 12 to 18 carbon atoms in the alkyl chain are preferred, with oleic acid being most preferred. The corresponding soaps can be used in the same way. The optional fatty acid/soaps are used in amounts up to 20%, often from 5% to 15%.

Detergent enzymes generally assist and enhance the removal of specific soils. Suitable enzymes may be proteases, amylases, lipases, glucose oxidases, cellulases or mixtures thereof. In the claimed liquid concentrated compositions, proteases and amylases are preferred. They are often used in an amount of 0.01% to 2%.

All generally known enzyme stabilizing systems can be used in the compositions according to the invention in the amount established in the art. Examples of suitable stabilizing systems include short-chain C1-4 carboxylic acids, especially formic acid, in combination with small amounts of calcium, boric acid and the water-soluble salts thereof, optionally in combination with polyols.

Suitable alkylene polyaminopolyalkylene phosphonic acids for use herein include ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid or the salts thereof. These polyphosphonates are advantageously used in an amount of from 0.1% to 3%, preferably from 0.4% to 1.2%; the preferred tetra and pentamethylene phosphonate species may also be used in combination, e.g. in a tetra:penta weight ratio of from 3:1 to 1:3.

Acceptable detergent foam regulators herein include hydrogenated fatty acids having 16 to 22 carbon atoms in the alkyl chain and alkylated polysiloxanes such as dimethylpolysiloxanes.

The fatty acid foam regulator is often used in an amount of 0.5 to 5%, whereas the silicone can be used effectively in amounts in the range of 0.05% to 0.5%. The foam regulator can also be formed from a combination of hydrogenated fatty acid and silicone.

In the presence of oxidizable materials, the compositions of the invention may also contain known antioxidants in amounts established in the art, e.g., 0.01% to 0.25% (based on the total composition). These antioxidants are often incorporated in conjunction with unsaturated organic acids. Although many suitable antioxidants are already known and available for this purpose, particularly preferred for use in the compositions of the invention are 2,6-di-tert-butyl-p-cresol, commonly known as butylated hydroxytoluene, BHT, and 2-tert-butyl-4-hydroxyanisole. Other suitable antioxidants are 4,4'-thiobis(6-tert-butyl-m-cresol) and 2-methyl-4,6-dinonylphenol.

Builders such as sodium tripolyphosphate, sodium pyrophosphate, tartrate monosuccinic acid, citric acid, (C₁₂-C₁₆) alkenyl succinates, fully hydrated zeolite A with a particle diameter of 1 to 10 µm or combinations thereof are often used in amounts of 2% to 25%.

Chelating agents such as alkylenepolyamino-polyalkylenepolycarboxylic acids and/or polyphosphonic acids are often used in amounts of 0.1 to 3%.

Known fabric softening agents including the ditallow dimethyl ammonium salts and imidazolinium salts as well as bentonite clays as known from DE-PS 23 34 899 may also be used depending on the effect of the composition being considered. If the softening agents are present, they may typically represent 2% to 8%.

The liquid matrix components should also comprise a solvent selected from the lower aliphatic alcohols having 2 to 6 carbon atoms and 1 to 3 hydroxyl groups, for example ethanol; n-propanol; isopropanol; butanol; 1,2-propanediol; 1,3-propanediol.

Other liquid matrix components are further optional components in the compositions of the invention. This component together with water and the lower aliphatic alcohols can constitute the solvent matrix for e.g. the concentrated liquid embodiments. Suitable classes of components include ethers of diethylene glycol and lower aliphatic monoalcohols having 1 to 4 carbon atoms. Specific examples of phase regulators are monomethyl, ethyl, propyl and monobutyl ethers of diethylene glycol. The liquid matrix components can be used in varying amounts depending on e.g. the total amount of components in the composition. In the concentrated liquid heavy-duty detergent compositions embodiments of the invention, the liquid solvent can constitute 5% to 30%. The heavy-duty detergent compositions of the invention represent a preferred embodiment of the claimed technology. These compositions can have the following formula: % by weight Generally preferred Anionic surfactant Non-ionic surfactant Builder Chelating agent Enzyme protease Amylase Brightener - hydrophobic Conventional Water Solvent (liquid matrix)

EXAMPLE I

The tendency of different brighteners to stain tissue is evaluated in the following composition.

Component wt.%

Linear C₁₂-alkylbenzenesulfonic acid 10.0

C₁₂₋₁₄-alkylsulphuric acid 3.0

C₁₄₋₁₅-alcohol polyethoxylate (7EO) 12.0

C₁₂₋₁₄-fatty acid 11.0

Oleic acid 4.0

Citric acid (anhydrous) 1.0

Dimethylenetriaminepentamethylenephosphonic acid 0.8

Triethanolamine 6.0

Sodium hydroxide to pH 7.7 3.4

Propylene glycol 1.6

ethanol 6.0

Alkaline protease (1.5 AU/g) 0.9

Formic acid 0.66

alpha-amylase (300 KAU/g) 0.1

Brightener 0.175

Minor components and water rest to 100

Undiluted detergent samples containing the above detergent brighteners are applied to non-brightened 100% cotton fabric samples and left for 10 minutes. The fabric samples are then washed with the same detergent solution (1% product concentration, 30ºC, gentle agitation) and spun dry. The fabric samples are then graded under UV light based on the coloration by the brightener using the following scale:

0 no visible staining

T Traces of staining

1.0 very slight staining

1.5 slight staining

2.0 moderate light staining

2.5 moderate staining

3.0 strong staining

The results are as follows: Brightener Stain classification blue nightdress pink undershirt green shorts blue undershirt pink nightdress blue pillowcase beige muslin (technical swatch) beige cotton knit Indian cotton pink tracksuit

The above results confirm the reduced brightener staining on a wide variety of fabrics by the tetraanilino brightener (A) in accordance with the invention.

The superiority of brightener deposition during The laundry washing process is shown in a complementary manner by means of measurements of the brightener increase.

Brightener increase is the speed at which a brightener is deposited on the brightened and non-brightened fabric samples. The increase is measured as follows:

Test conditions

Miele® W765, 60ºC short cycle, 180 ml Product use (1% product concentration) Ballast filling: 2 kg bleached 100% cotton (90ºC wash with perborate/sodium tripolyphosphate), not bleached.

Indicators

Unbleached terry cloth: unbleached, non- bleached terry cloth which has been bleached by washing once at 90ºC with perborate/sodium tripolyphosphate; bleached terry cloth: bleached, brightened terry cloth which has been washed five times with a heavy-duty detergent at 90ºC.

Measurement

Re-emission at 440 nm from non-brightened terry cloth fabric at the beginning: 83.88

Re-emission at 440 nm from brightened terry cloth at the beginning: 149.13

Results: Reemission at 440 nm n washes non-bleached fabric sample bleached fabric sample

EXAMPLE II

Additional liquid compositions in accordance with the invention include the following ingredients:

% by weight Linear C₁₂-alkylbenzenesulfonic acid 6

C₁₃-C₁₅-oxo alcohol, condensed with 7 moles ethylene oxide 3

C₁₂-C₁₄-fatty diethanolamide 2

Sodium tripolyphosphate 23

Carboxymethylcellulose 0.3

Hydrogenated fatty acid (C₁₈-C₂₂) 1

Polydimethylsiloxane 0.2

Brightener (see below) 0.15-0.20

proteolytic enzyme (1.5 Au basis) 0.5

Glycerine 5

Sodium tetraborate 2

Sodium hydroxide (1% solution) to 9.0

optional ingredients including

Perfume, brightener 1.0

The brightener is used by:

- A

- a mixture of A and vii (in a weight ratio of 1 : 1); and

- a mixture of A and iii (in a weight ratio of 9:1). EXAMPLES Dodecylbenzosulfonic acid C₁₂₋₁₈C₁₄-alkyltriethoxysulfate-Na C₁₂₋₁₈C₁₄-dimethylamine oxide C₁₂₋₁₈C₁₃-oxaalcohol condensed with 6.5 moles EO C₁₂₋₁₈C₁₈-fatty acid Oleic acid Citric acid Tartratemonosuccinic acid Ditallowdimethylammonium chloride Diethylenetriaminepentaacetic acid Tetraethylenepentamine-15-19 EO C₁₂₋₁₈C₁₄-alkenylsuccinic acid Ethanol Polyethylene glycol terephthalate (1) Diethylenetriaminopentamethylenephosphonic acid Monoethanolamine Triethanolamine Propanediol Proteolytic enzyme (1.5 AU/g basis) Amylolytic enzyme Brightener A Sodium formate Sodium hydroxide to adjust the pH (1% solution)* Optional ingredients including perfume, colorant, silicone, foam regulator, aminosilane, opacifier, water - balance to 100 - * expressed as pH units (1) as described in more detail in European patent application 85202053.6 dated 12.12.1985.

Claims (7)

1. A liquid, aqueous laundry detergent composition comprising (a) 3% to 60% by weight of a surfactant selected from anionic and nonionic surfactants and mixtures thereof; and (b) from 0.01% to 1% by weight of a hydrophobic disulfonated brightener which represents at least 40% by weight of the total brightener in the composition, which hydrophobic brightener has the formula: wherein the R₁₋₄ residues are selected from the group consisting of tetra-anilino, tetra-piperazino, tetra-cyclhexylamino, dianilino-dipiperazino and dianilino-dicyclohexylamino; and (c) a solvent selected from lower aliphatic alcohols having 2 to 6 carbon atoms and 1 to 3 hydroxyl groups. 2. The composition of claim 1, wherein the surfactant represents 10% to 50% by weight. 3. Composition according to claim 2, wherein the hydrophobic brightener is formed from the tetra-anilinoderivative which is in a Amount of 0.07 wt.% to 0.3 wt.%. 4. A composition according to claim 1, wherein the surfactant is formed from a mixture of anionic and nonionic surfactants in a weight ratio of anionic surfactants to nonionic surfactants of from 1:1 to 3:1. 5. A composition according to claims 1 and 4, wherein the nonionic surfactant is formed from a combination of nonionic ethoxylates and amine oxides in a weight ratio of ethoxylate to amine oxide of 50:1 to 8:1. 6. A composition according to claim 1, wherein the brightener is formed by a mixture of the hydrophobic brightener and a conventional detergent brightener, the hydrophobic brightener representing at least 40% by weight of the total brightener. 7. Composition according to claims 1 and 6, wherein the conventional brightener is 4,4'-bis((4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino)-2-stilbenesulfonate sodium salt.