WO1994010285A1

WO1994010285A1 - Fabric softeners containing dyes for reduced staining

Info

Publication number: WO1994010285A1
Application number: PCT/US1993/010046
Authority: WO
Inventors: Errol Hoffman Wahl; Jeffrey Wayne Watson; Kimberley Suzanne Kramer
Original assignee: The Procter & Gamble Company
Priority date: 1992-10-26
Filing date: 1993-10-20
Publication date: 1994-05-11
Also published as: CN1092124A; JPH08502784A; BR9307311A; CA2147840A1; MX9306673A; EP0665877A1

Abstract

The present invention relates to fabric softening compositions providing an increase in the ease of stain removal on fabrics such as cottons and polyesters, comprising: (a) from about 3 % to about 50 % by weight of fabric softener; and (b) from about 1 ppm to about 1,000 ppm of a stable dye system, whereby the dye system comprises selected water-soluble LiquitintR dyes.

Description

FABRIC SOFTENERS CONTAINING DYES FOR REDUCED STAINING

TECHNICAL FIELD

The present invention relates to the selection of certain nonionic dyes to be incorporated into liquid fabric softening compositions to reduce staining of fabrics, even at high levels of dyes. BACKGROUND OF THE INVENTION

Liquid fabric softening compositions are widely used by consumers during the rinse cycles of automatic laundry operations to impart a smooth, pliable, and fluffy texture to the laundered fabrics. The present invention is based on the discovery that only some of the nonionic Liqultint* dyes, which are available from MiHiken Chemical Co., reduce staining, via an increased ease of stain removal, and are stable in fabric softening compositions. Colorants are generally added to liquid fabric softening compo- sitions for visual appeal to the consumer as well as identity of the product. Fabric staining caused by softener compositions can be permanent and is not always obvious to the consumer due to a relatively low incident of occurrence.

The selected Liqultint* dyes of the present invention are more easily removed from fabric once dye staining occurs, and therefore reduce fabric staining for those fabrics which are usually washed in the typical laundering operation, i.e., cottons and polyester. Also, by selecting the appropriate Liquitint* dye, color stability in the composition can be maximized. High color loading and bright coloration as well as minimal complexation with other ingredients of the softener composition are possible. Mixing specific Liquitlnt* dyes with other types of dyes can also yield lower staining colorant systems. SUMMARY OF THE INVENTION The present invention relates to fabric softening compo¬ sitions which reduce the staining of fabrics. The present invention comprises: (a) from about 3% to about 50% by weight of fabric softener;

(b) from about 1 ppm to about 1,000 ppm, preferably from about 5 ppm to about 250 ppm, more preferably from about 10 ppm to about 100 ppm, of a dye system; and

(c) a liquid carrier; whereby the dye system comprises a dye selected from the group consisting of:

1. Liquitint^® Blue HP;

2. Liquitint® Blue 65;

3. Liquitint^® Experimental Yellow 8949-43; 4. Liquitint^® Green HMC;

5. Liquitint^® Patent Blue;

6. Liquitint® Royal Blue;

7. Liquitint^® Teal ;

8. Liquitint^® Violet; 9. Liquitint^® Yellow II; and 10. Mixtures thereof. Preferably the dye is selected form the group consisting of 2, 3, and 5, and mixtures thereof.

The pH of the composition is less than about 6, preferably less than about 4, more preferably from about 1.8 to about 3.5.

DETAILED DESCRIPTION OF THE INVENTION The Dves The composition of the present invention contains a dye system whereby the dye system comprises a dye selected from the group consisting of:

1. Liquitint^® Blue HP;

2. Liquitint^® Blue 65;

3. Liquitint^® Experimental Yellow 8949-43;

4. Liquitint^® Green HMC; 5. Liquitint^® Patent Blue;

6. Liquitint^® Royal Blue;

7. Liquitint^® Teal; 8. Liquitint® Violet;

9. Liquitint^® Yellow II; and 10. Mixtures thereof.

Preferably, the dye is selected from the group consisting of 2, 3, 5, and mixtures thereof. Although Liquitint® dyes are commer¬ cially available and are alleged to be non-staining and color stable, not all of these dyes exhibit color stability and non- staining properties in fabric softener compositions. It is not obvious to one skilled in the art which of these dyes would provide an increase in stain removal and provide stability in fabric softener compositions. The problem of fabric staining by softener compositions is also not always obvious, due to the relatively low incidence of occurrence to the consumer. These dyes can also be mixed with other commercially available (con- ventional) dyes which would be selected by one skilled in the art for use in fabric softeners. These conventional dyes are selected from the group consisting of:

1. Acid Red #1;

2. D&C Yellow #10; 3. Polar Brilliant Blue (Acid Blue #127:1); and 4. Mixtures thereof; wherein the ratio of nonionic Liquitint^® dye to conventional dye is from about 1:1 to about 1:0.1, preferably from about 1:0.75 to about 1:0.1, more preferably from about 1:0.35 to about 1:0.1. The level of conventional dye should be minimized to reduce the staining potential of the dye system. For example, Patent Blue can be mixed with D&C Yellow #10 at a ratio of from about 1:0.75 to about 1:0.25; or Patent Blue can be mixed with Acid Red #1 at a ratio of from about 1:0.35 to about 1:0.1. The Liquitint® dyes of the present invention are highly water-soluble. Because these dyes are water-soluble, high color loading is possible without precipitation of the dye, and there¬ fore bright coloration is possible. Also, because they are water-soluble and non-reactive, these dyes are compatible with many fragrances and preservatives and tend not to complex with other ingredients of the composition. These dyes provide stability in a pH range of from about 2 to about 10 which is important, especially in biodegradable softener compositions which tend to have a lower pH value (in the range of from about 2 to about 4; neat pH).

These dyes can be added to the composition at any point during the processing including into the water seat, after the addition of electrolyte (hot), or post-addition to the cooled product. The dyes should not be added to the organic premix (co-melt of all softener actives) because a significant degrada¬ tion of the dye can occur. For ease of processing these dyes can be post-added to the cooled product. If mixtures of dyes are utilized, these dyes can either be premixed before addition to the composition or the dyes can be mixed into the composition at different points.

The level of dye of the present invention is an amount which provides from about 1 ppm^' to about 1,000 ppm, preferably from about 5 ppm to about 250 ppm, more preferably from about 10 ppm to about 100 ppm in the composition. Colors from dyes are usually detectable in the composition at dye concentrations of approximately 5 ppm or greater. Liquitint^® dyes can be mixed at any ratio to provide a greater variety of colors. For example, Experimental Yellow 8949-43 and Patent Blue can be mixed at a ratio of from about 1:1 to about 1.5:1 to provide colors ranging from blue to green.

Under stress conditions the staining characteristics of these dyes showed significant differences. Experts evaluated and ranked these dyes as follows (lowest staining to highest staining char¬ acteristic):

1. Liquitint^® Patent Blue;

2. Liquitint^® Royal Blue; 3. Liquitint^® Violet;

4. Liquitint^® Blue HP;

5. Liquitint^® Teal;

6. Liquitint® Experimental Yellow 8949-43;

7. Liquitint^® Green HMC; and 8. Liquitint^® Yellow II. These dyes provide an increase in the ease of stain removal versus a commonly used blue dye, Acid Blue #127:1, used in liquid fabric softener compositions.

The Fabric Softeners The fabric softening agent in the composition is from about 3% to about 50%, preferably from about 15% to about 35%, by weight of the composition. The lower limits reflect the amount needed to effectively soften fabrics when added to laundry rinse cycle in the usual manner. The higher limits reflect concentrated products which provide reduced packaging and distribution costs. Some preferred compositions are disclosed in U.S. Pat. No. 4,661,269, issued April 28, 1987, which is incorporated herein by reference.

The fabric softener herein comprises from about 2% to about 50% of di-long-chain quaternary ammonium fabric softening compound described in detail under (1) and (2) below.

Preferably the di-long-chain softener is biodegradable diester quaternary ammonium compound which is at least 80% diester.

The compositions can also be concentrated aqueous liquids, containing from about 15% to about 50%, preferably from about 15% to about 35%, more preferably from about 15% to about 30%, of the biodegradable diester softening compound. The liquid compositions can be added to the rinse to provide adequate usage concentration (e.g., from about 10 to about 1,000 ppm, preferably from about 50 to about 500 ppm, of total active ingredient).

Di-Long-Chain Quaternary Ammonium Compound (1) Diester Quaternary Ammonium Compound Preferably, the composition of the present invention has from about 3% to about 50%, preferably from about 15% to about 35%, more preferably from about 15% to about 30%, of said diester quaternary ammonium fabric softening compound (DEQA), preferably DEQA having the formula:

( )4-m " N+ - [(CH₂)_n - Y - R²]m X^' wherein each Y - -0-(0)C-, or -C(0)-0-; - 2 or 3; each n = 1 to 4; each R substituent is a short chain Cj-Cβ, preferably C1-C3 alkyl or hydroxyalkyl group, e.g., methyl (most preferred), ethyl, propyl, hydroxyethyl, and the like, benzyl or mixtures thereof; each R² is a long chain C10-C22 hydrocarbyl, or substituted hydrocarbyl substituent, preferably C15-C19 alkyl and/or alkylene, most preferably C15-C17 straight chain alkyl and/or alkylene; and the counterion, X", can be any softener-compatible anion, for example, chloride, bromide, methylsulfate, formate, sulfate, nitrate and the like. It will be understood that substituents R and R² can option¬ ally be substituted with various groups such as alkoxyl or hydroxyl groups, and/or can be saturated, unsaturated, straight, and/or branched so long as the R² groups maintain their basically hydrophobic character. The preferred compounds can be considered to be diester variations of ditallow dimethyl ammonium chloride (DTDMAC), which is a widely used fabric softener. At least 80% of the DEQA is in the diester form, and from 0% to about 20% can be DEQA monoester (e.g., only one -Y-R² group).

As used herein, when the diester is specified, it will include the monoester that is normally present in the active raw material. For softening, the percentage of diester should be high.

The following are non-limiting examples (wherein all long- chain alkyl substituents are straight-chain): [HO-CH(CH3)CH2][CH3]+N[CH2CH2θC(0)Ci5H3i]2 Br" [C2H5]2⁺N[CH₂CH2θC(0)Ci7H₃5]2 Cl^" [CH3][C2H5]⁺N[CH₂CH₂OC(0)Ci3H27]2 I^" [C3H7][C2H5l⁺N[CH2CH2θC(0)Ci5H3l]2 SO4ΘCH3 [CH3]2+N-CH2CH2θC(0)Ci5H3i Cl" I

CH2CH20C(0)CπH35 [CH2CH2OH][CH3]+N[CH2CH20C(0)R ]2 Cl^" [CH3]2⁺N[CH2CH2θC(0)R²] Cl" where -C(0)R² is derived from hardened tallow. Since the foregoing compounds (diesters) are somewhat labile to hydrolysis, they should be handled rather carefully when used to formulate the compositions herein. For example, stable liquid compositions herein are formulated at a pH in the range of about 2 to about 5, preferably from about 2 to about 4.5, more preferably from about 2 to about 4. The pH can be adjusted by the addition of a Bronsted acid. pH ranges for making stable softener compo- sitions containing diester quaternary ammonium fabric softening compounds are disclosed in U.S. Pat. No. 4,767,547, supra, and is incorporated herein by reference.

The diester quaternary ammonium fabric softening compound (DEQA) can also have the general formula:

wherein each R, R², and X have the same meanings as before. Such compounds include those having the formula: [CH3]3+ N[CH2CH(CH2θC[0]R²)OC(0)R²] Cl" where -0C(0)R² is derived from hardened tallow.

Preferably each R is a methyl or ethyl group and preferably each R² is in the range of CJS to Cig. Degrees of branching, substitution and/or non-saturation can be present in the alkyl chains. The anion X" in the molecule is preferably the anion of a strong acid and can be, for example, chloride, bromide, iodide, sulphate or methyl sulphate; the anion can carry a double charge in which case X" represents half a group. These compounds, in general, are more difficult to formulate as stable concentrated liquid compositions.

These types of compounds and general methods of making them are disclosed in U.S. Pat. No. 4,137,180, Naik et al., issued Jan. 30, 1979, which is incorporated herein by reference. (2) Acyclic Quaternary Ammonium Salts The composition of the present invention can contain from about 2% to about 35%, preferably from about 2% to about 15%, of an acyclic quaternary ammonium salt of the formula:

wherein R, R², and A" have the same meaning as before for DEQA. RIO i_S selected from the group consisting of R and R².

Examples of this component are the well known dialkyldi¬ methylammonium chloride, ditallowdimethylammonium methylsulfate, di(hydrogenated tallow) dimethylammonium chloride, etc.

Optional ingredients In addition to the above components, the composition can have one or more of the following optional ingredients.

(1) Optional Viscositv/Dispersibilitv Modifiers The composition of the present invention can contain from about 0.1% to about 30% of viscosity and/or dispersibility modi¬ fier selected from the group consisting of:

1. single-long-chain-alkyl, cationic surfactant;

2. nonionic surfactant with at least 8 ethoxy moieties; or 3. mixtures thereof.

(l)(a) Single-Long-Chain Alkyl Cationic Surfactant The mono-long-chain-alkyl (water-soluble) cationic surfac¬ tants are at a level of from 0% to about 15%, preferably from about 0.5% to about 10%, the total single-long-chain cationic surfactant present being at least at an effective level.

Such mono-long-chain-alkyl cationic surfactants useful in the present invention are, preferably, quaternary ammonium salts of the general formula:

[R N+R3] X- wherein the R² group is C10-C22 hydrocarbon group, preferably a C12-C18 alkyl group. This R² group can be attached to the cati¬ onic nitrogen atom through a group containing one, or more, ester, amide, ether, amine, etc., preferably ester, linking groups which can be desirable for increased hydrophilicity, biodegradability, etc. Such linking groups are within about 1 to about 4, prefer¬ ably 3 carbon atoms of the nitrogen atom. Each R is a hydrogen or C1-C4 alkyl or substituted (e.g., hydroxy) alkyl, preferably methyl, and the counterion X" is a softener compatible anion, for example, chloride, bromide, methyl sulfate, etc. The ranges above represent the amount of the single-long- chain-alkyl cationic surfactant which is added to the composition of the present invention. The ranges do not include the amount of monoester which is already present in component (A), the diester quaternary ammonium compound, the total present being at least at an effective level .

Suitable biodegradable single-long-chain alkyl cationic surfactants containing an ester linkage in the long chain are described in U.S. Pat. No. 4,840,738, Hardy and Walley, issued June 20, 1989, said patent being incorporated herein by reference.

It will be understood that the main function of the water- soluble cationic surfactant is to lower the viscosity and/or increase the dispersibility of the diester softener and it is not, therefore, essential that the cationic surfactant itself have substantial softening properties, although this may be the case. Also, surfactants having only a single long alkyl chain, presum¬ ably because they have greater solubility in water, can protect the diester softener from interacting with anionic surfactants and/or detergent builders that are carried over into the rinse.

Other cationic materials with ring structures such as alkyl imidazoline, imidazolinium, pyridine, and pyridinium salts having a single C12-C30 alkyl chain can also be used. Very low pH is required to stabilize, e.g., imidazoline ring structures.

Some alkyl imidazolinium salts useful in the present inven¬ tion have the general formula:

wherein Y² is -0-, -C(0)-0-, -0-(0)-C-, -C(0)-N(R9), or -N(R⁹)-C(0)- in which R⁵ is a divalent C1-C4 alkylene group; R⁶ is a hydrogen, a hydroxyalkyl group, or C1-C4 saturated alkyl radical; R? and R⁸ are each independently selected from R and R² as defined hereinbefore for the single-long-chain cationic sur¬ factant with only one being R²; and R⁹ is a hydrogen or a C1-C4 alkyl radical. A preferred quate nization method (where R⁶ is hydrogen) is disclosed in U.S. Pat. No. 4,954,635, Rosario-Jansen et al., issued Sept. 4, 1990, the disclosure of which is incor¬ porated herein by reference.

Some alkyl pyridinium salts useful in the present invention have the general formula:

wherein R and X" are as defined above. A typical material of this type is cetyl pyridinium chloride.

Some alkanamide alkylene pyridinium salts useful in the present invention have the general formula:

wherein R², R-, and X- are as defined above.

(l)(b) Nonionic Surfactant (Alkoxylated Materials)

Suitable nonionic surfactants, which can serve as a viscosity/dispersibility modifier, include addition products of ethylene oxide and, optionally, propylene oxide, with fatty alcohols, fatty acids, fatty amines, etc.

Any of the alkoxylated materials of the particular type described hereinafter can be used as the nonionic surfactant. In general terms, the nonionics herein, when used alone, are at a level of from 0% to about 5%, preferably from about 0.1% to about 5%, more preferably from about 0.2% to about 3%. Suitable com¬ pounds are substantially water-soluble surfactants of the general formula:

R² - Y - (C2H4θ)_z - C2H4OH wherein R² is selected from the group consisting of primary, secondary and branched chain alkyl and/or acyl hydrocarbyl groups; primary, secondary and branched chain alkenyl hydrocarbyl groups; and primary, secondary and branched chain alkyl- and alkenyl-sub¬ stituted phenolic hydrocarbyl groups; said hydrocarbyl groups having a hydrocarbyl chain length of from about 8 to about 20, preferably from about 10 to about 18 carbon atoms. More prefer¬ ably the hydrocarbyl chain length is from about 16 to about 18 carbon atoms. In the general formula for the ethoxylated nonionic surfactants herein, Y is typically -0-, -C(0)0-, -C(0)N(R)-, or -C(0)N(R)R-, in which R², and R, when present, have the meanings given hereinbefore for the single long chain cationic surfactant, and/or R can be hydrogen, and z is at least about 8, preferably at least about 10-11. Performance and, usually, stability of the softener composition can sometimes decrease when fewer ethoxylate groups are present.

The nonionic surfactants herein are typically characterized by an HLB (hydrophilic-lipophilic balance) of from about 7 to about 20, preferably from about 8 to about 15. Of course, by defining R² and the number of ethoxylate groups, the HLB of the surfactant is, in general, determined. However, it is to be noted that the nonionic ethoxylated surfactants useful herein, for concentrated liquid compositions, contain relatively long chain R² groups and are relatively highly ethoxylated. While shorter alkyl chain surfactants having short ethoxylated groups may possess the requisite HLB, they are not normally as effective herein.

Examples of nonionic surfactants follow. The nonionic surfactants of this invention are not limited to these examples. In the examples, the integer defines the number of ethoxyl (EO) groups in each molecule. A. Straight-Chain. Primary Alcohol Alkoxylates

The deca-, undeca-, dodeca-, tetradeca-, and pentadeca- ethoxylates of n-hexadecanol , and n-octadecanol having an HLB within the range recited herein are useful viscosity/dispersi- bility modifiers in the context of this invention. Exemplary ethoxylated primary alcohols useful herein as the viscosity/dis- persibility modifiers of the compositions are n-CιβEO(lO); and n-CιoEO(ll). The ethoxylates of mixed natural or synthetic alcohols in the "tallow" chain length range are also useful herein. Specific examples of such materials include tallow- alcohol-EO(ll), tallowalcohol-E0(18), and tallowalcohol -EO(25). B. Straight-Chain. Secondary Alcohol Alkoxylates The deca-, undeca-, dodeca-, tetradeca-, pentadeca-, octadeca-, and nonadeca-ethoxylates of 3-hexadecanol , 2-octadeca- nol, 4-eicosanol, and 5-eicosanol having and HLB within the range recited herein are useful viscosity/dispersibility modifiers in the context of this invention. Exemplary ethoxylated secondary alcohols useful herein as the viscosity/dispersibility modifiers of the compositions are: 2-CιeE0(ll); 2-C2θEO(ll); and

C. Alkyl Phenol Alkoxylates

As in the case of the alcohol alkoxylates, the hexa- through octadeca-ethoxylates of alkylated phenols, particularly monohydric alkylphenols, having an HLB within the range recited herein are useful as the viscosity/dispersibility modifiers of the instant compositions. The hexa- through octadeca-ethoxylates of p-tri- decylphenol, m-pentadecylphenol, and the like, are useful herein. Exemplary ethoxylated alkylphenols useful as the viscosity/dis¬ persibility modifiers of the mixtures herein are: p-tridecylphenol E0(11) and p-pentadecylphenol E0(18). As used herein and as generally recognized in the art, a phenylene group in the nonionic formula is the equivalent of an alkylene group containing from 2 to 4 carbon atoms. For present purposes, nonionics containing a phenylene group are considered to contain an equivalent number of carbon atoms calculated as the sum of the carbon atoms in the alkyl group plus about 3.3 carbon atoms for each phenylene group.

D. Olefinic Alkoxylates

The alkenyl alcohols, both primary and secondary, and alkenyl phenols corresponding to those disclosed immediately hereinabove can be ethoxylated to an HLB within the range recited herein and used as the viscosity/dispersibility modifiers of the instant compositions.

E. Branched Chain Alkoxylates Branched chain primary and secondary alcohols which are available from the well-known "0X0" process can be ethoxylated and employed as the viscosity/dispersibility modifiers of compositions herein. The above ethoxylated nonionic surfactants are useful in the present compositions alone or in combination, and the term "nonionic surfactant" encompasses mixed nonionic surface active agents. (l)(c) Mixtures

The term "mixture" includes the nonionic surfactant and the single-long-chain-alkyl cationic surfactant added to the compo¬ sition in addition to any monoester present in the DEQA.

Mixtures of the above viscosity/dispersibility modifiers can be highly desirable. The single long chain cationic surfactant can provide improved dispersibility and protection for the primary

DEQA against anionic surfactants and/or detergent builders that are carried over from the wash solution.

Mixtures of the viscosity/dispersibility modifiers are typically present at a level of from about 0.1% to about 30%, preferably from about 0.2% to about 20%, by weight of the com¬ position.

(2) Optional Essentially Linear Fatty Acid and/or Fatty Alcohol Monoesters Optionally, an essentially linear fatty monoester can be added in the composition of the present invention and is often present in at least a small amount as a minor ingredient in the DEQA raw material.

Monoesters of essentially linear fatty acids and/or alcohols, which aid said modifier, contain from about 12 to about 25, preferably from about 13 to about 22, more preferably from about 16 to about 20, total carbon atoms, with the fatty moiety, either acid or alcohol, containing from about 10 to about 22, preferably from about 12 to about 18, more preferably from about 16 to about 18, carbon atoms. The shorter moiety, either alcohol or acid, contains from about 1 to about 4, preferably from about 1 to about 2, carbon atoms. Preferred are fatty acid esters of lower alcohols, especially methanol. These linear monoesters are sometimes present in the DEQA raw material or can be added to a DEQA premix as a premix fluidizer, and/or added to aid the vis¬ cosity/dispersibility modifier in the processing of the softener composition. (3) Optional Nonionic Softener An optional additional softening agent of the present inven¬ tion is a nonionic fabric softener material. Typically, such nonionic fabric softener materials have an HLB of from about 2 to about 9, more typically from about 3 to about 7. Such nonionic fabric softener materials tend to be readily dispersed either by themselves, or when combined with other materials such as single- long-chain alkyl cationic surfactant described in detail herein¬ before. Dispersibility can be improved by using more single- long-chain alkyl cationic surfactant, mixture with other materials as set forth hereinafter, use of hotter water, and/or more agitation. In general, the materials selected should be rela¬ tively crystalline, higher melting, (e.g., >~50'C) and relatively water-insoluble. The level of optional nonionic softener is typically from about 0.5% to about 10%, preferably from about 1% to about 5%.

Preferred nonionic softeners are fatty acid partial esters of polyhydric alcohols, or anhydrides thereof, wherein the alcohol, or anhydride, contains from 2 to about 18, preferably from 2 to about 8, carbon atoms, and each fatty acid moiety contains from about 12 to about 30, preferably from about 16 to about 20, carbon atoms. Typically, such softeners contain from about one to about 3, preferably about 2 fatty acid groups per molecule.

The polyhydric alcohol portion of the ester can be ethylene glycol, glycerol, poly (e.g., di-, tri-, tetra-, penta-, and/or hexa-) glycerol, xylitol, sucrose, erythritol, pentaerythritol, sorbitol or sorbitan. Sorbitan esters and polyglycerol ono- stearate are particularly preferred.

The fatty acid portion of the ester is normally derived from fatty acids having from about 12 to about 30, preferably from about 16 to about 20, carbon atoms, typical examples of said fatty acids being lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid.

Highly preferred optional nonionic softening agents for use in the present invention are the sorbitan esters, which are esterified dehydration products of sorbitol, and the glycerol esters. Sorbitol, which is typically prepared by the catalytic hydrogenation of glucose, can be dehydrated in well known fashion to form mixtures of 1,4- and 1,5-sorbitol anhydrides and small amounts of isosorbides. (See U.S. Pat. No. 2,322,821, Brown, issued June 29, 1943, incorporated herein by reference.)

The foregoing types of complex mixtures of anhydrides of sorbitol are collectively referred to herein as "sorbitan." It will be recognized that this "sorbitan" mixture will also contain some free, uncyclized sorbitol. The preferred sorbitan softening agents of the type employed herein can be prepared by esterifying the "sorbitan" mixture with a fatty acyl group in standard fashion, e.g., by reaction with a fatty acid halide or fatty acid. The esterification reaction can occur at any of the available hydroxy! groups, and various mono-, di-, etc., esters can be prepared. In fact, mixtures of mono-, di-, tri-, etc., esters almost always result from such reactions, and the stoichiometric ratios of the reactants can be simply adjusted to favor the desired reaction product.

For commercial production of the sorbitan ester materials, etherification and esterification are generally accomplished in the same processing step by reacting sorbitol directly with fatty acids. Such a method of sorbitan ester preparation is described more fully in MacDonald; "Emulsifiers:" Processing and Quality Control:, Journal of the American Oil Chemists Society. Vol. 45, October 1968.

Details, including formula, of the preferred sorbitan esters can be found in U.S. Pat. No. 4,128,484, incorporated hereinbefore by reference.

Certain derivatives of the preferred sorbitan esters herein, especially the "lower" ethoxylates thereof (i.e., mono-, di-, and tri-esters wherein one or more of the unesterified -OH groups contain one to about twenty oxyethylene moieties [Tweens^®] are also useful in the composition of the present invention. There¬ fore, for purposes of the present invention, the term "sorbitan ester" includes such derivatives. For the purposes of the present invention, it is preferred that a significant amount of di- and tri- sorbitan esters are present in the ester mixture. Ester mixtures having from 20-50% mono-ester, 25-50% di-ester and 10-35% of tri- and tetra-esters are preferred.

The material which is sold commercially as sorbitan mono¬ ester (e.g., monostearate) does in fact contain significant amounts of di- and tri-esters and a typical analysis of sorbitan monostearate indicates that it comprises ca. 27% mono-, 32% di- and 30% tri- and tetra-esters. Commercial sorbitan monostearate therefore is a preferred material. Mixtures of sorbitan stearate and sorbitan pal itate having stearate/palmitate weight ratios varying between 10:1 and 1:10, and 1,5-sorbitan esters are useful. Both the 1,4- and 1,5-sorbitan esters are useful herein. Other useful alkyl sorbitan esters for use in the softening compositions herein include sorbitan monolaurate, sorbitan mono- myristate, sorbitan monopalmitate, sorbitan monobehenate, sorbitan monooleate, sorbitan dilaurate, sorbitan dimyristate, sorbitan dipalmitate, sorbitan distearate, sorbitan dibehenate, sorbitan dioleate, and mixtures thereof, and mixed tallowalkyl sorbitan mono- and di-esters. Such mixtures are readily prepared by reacting the foregoing hydroxy-substituted sorbitans, particularly the 1,4- and 1,5-sorbitans, with the corresponding acid or acid chloride in a simple esterification reaction. It is to be recog- nized, of course, that commercial materials prepared in this manner will comprise mixtures usually containing minor proportions of uncyclized sorbitol, fatty acids, polymers, isosorbide struc¬ tures, and the like. In the present invention, it is preferred that such impurities are present at as low a level as possible. The preferred sorbitan esters employed herein can contain up to about 15% by weight of esters of the C20^_C26_> -ⁿ- higher, fatty acids, as well as minor amounts of Cs, and lower, fatty esters.

Glycerol and polyglycerol esters, especially glycerol, diglycerol, triglycerol, and polyglycerol mono- and/or di- esters, preferably mono-, are also preferred herein (e.g., polyglycerol monostearate with a trade name of Radiasurf 7248). Glycerol esters can be prepared from naturally occurring triglycerides by normal extraction, purification and/or interesterification pro¬ cesses or by esterification processes of the type set forth hereinbefore for sorbitan esters. Partial esters of glycerin can also be ethoxylated to form usable derivatives that are included within the term "glycerol esters."

Useful glycerol and polyglycerol esters include mono-esters with stearic, oleic, palmitic, lauric, isostearic, myristic, and/or behenic acids and the diesters of stearic, oleic, palmitic, lauric, isostearic, behenic, and/or myristic acids. It is under¬ stood that the typical mono-ester contains some di- and tri-ester, etc.

The "glycerol esters" also include the polyglycerol, e.g., diglycerol through octaglycerol esters. The polyglycerol polyols are formed by condensing glycerin or epichlorohydrin together to link the glycerol moieties via ether linkages. The mono- and/or diesters of the polyglycerol polyols are preferred, the fatty acyl groups typically being those described hereinbefore for the sorbitan and glycerol esters. The performance of, e.g., glycerol and polyglycerol mono¬ esters is improved by the presence of the diester cationic material, described hereinbefore.

Still other desirable optional "nonionic" softeners are ion pairs of anionic detergent surfactants and fatty amines, or quaternary ammonium derivatives thereof, e.g., those disclosed in U.S. Pat. No. 4,756,850, Nayar, issued July 12, 1988, said patent being incorporated herein by reference. These ion pairs act like nonionic materials since they do not readily ionize in water. They typically contain at least two long hydrophobic groups (chains).

The ion-pair complexes can be represented by the following formula:

wherein each R⁴ can independently be C12- 20 a k l or alkenyl, and R⁵ is H or CH3. A- represents an anionic compound and includes a variety of anionic surfactants, as well as related shorter alkyl chain compounds which need not exhibit surface activity. A" is selected from the group consisting of alkyl sulfonates, aryl sulfonates, alkylaryl sulfonates, alkyl sulfates, dialkyl sulfo- succinates, alkyl oxybenzene sulfonates, acyl isethionates, acylalkyl taurates, alkyl ethoxylated sulfates, olefin sulfonates, benzene sulfonates, C1-C5 linear alkyl benzene sulfonates, or mixtures thereof.

The terms "alkyl sulfonate" and "linear alkyl benzene sulfo¬ nate" as used herein shall include alkyl compounds having a sulfonate moiety both at a fixed location along the carbon chain, and at a random position along the carbon chain. Starting alkyl- amines are of the formula:

R4

N - Rδ R* ^ wherein each R⁴ is C12-C20 alkyl or alkenyl, and R⁵ is H or CH3. The preferred anions (A^) useful in the ion-pair complex of the present invention include benzene sulfonates and C1-C5 linear alkyl benzene sulfonates (LAS), particularly C1-C3 LAS. Most preferred is C3 LAS. The benzene sulfonate moiety of LAS can be positioned at any carbon atom of the alkyl chain, and is commonly at the second atom for alkyl chains containing three or more carbon atoms.

More preferred are complexes formed from the combination of ditallow amine (hydrogenated or unhydrogenated) complexed with a benzene sulfonate or C1-C5 linear alkyl benzene sulfonate and distearyl amine complexed with a benzene sulfonate or with a C1-C5 linear alkyl benzene sulfonate. Even more preferred are those complexes formed from hydrogenated ditallow amine or distearyl amine complexed with a C1-C3 linear alkyl benzene sulfonate (LAS). Most preferred are complexes formed from hydrogenated ditallow amine or distearyl amine complexed with C3 linear alkyl benzene sulfonate. The amine and anionic compound are combined in a molar ratio of amine to anionic compound ranging from about 10:1 to about 1:2, preferably from about 5:1 to about 1:2, more preferably from about 2:1 to about 1:2, and most preferably 1:1. This can be accom- pushed by any of a variety of means, including but not limited to, preparing a melt of the anionic compound (in acid form) and the amine, and then processing to the desired particle size range. A description of ion-pair complexes, methods of making, and non-limiting examples of ion-pair complexes and starting amines suitable for use in the present invention are listed in U.S. Pat. No. 4,915,854, Mao et al., issued April 10, 1990, and U.S. Pat. No. 5,019,280, Caswell et al . , issued May 28, 1991, both patents incorporated herein by reference.

Generically, the ion pairs useful herein are formed by reacting an amine and/or a quaternary ammonium salt containing at least one, and preferably two, long hydrophobic chains (C12-C30, preferably C11-C20) with an anionic detergent surfactant of the types disclosed in said U.S. Pat. No. 4,756,850, especially at Col. 3, lines 29-47. Suitable methods for accomplishing such a reaction are also described in U.S. Pat. No. 4,756,850, at Col. 3, lines 48-65.

The equivalent ion pairs formed using C12-C30 fatty acids are also desirable. Examples of such materials are known to be good fabric softeners as described in U.S. Pat. No. 4,237,155, Kardouche, issued Dec. 2, 1980, said patent being incorporated herein by reference.

Other fatty acid partial esters useful in the present inven¬ tion are ethylene glycol distearate, propylene glycol distearate, xylitol monopalmitate, pentaerythritol monostearate, sucrose monostearate, sucrose distearate, and glycerol monostearate. As with the sorbitan esters, commercially available mono-esters normally contain substantial quantities of di- or tri- esters.

Still other suitable nonionic fabric softener materials include long chain fatty alcohols and/or acids and esters thereof containing from about 16 to about 30, preferably from about 18 to about 22, carbon atoms, esters of such compounds with lower (C1-C4) fatty alcohols or fatty acids, and lower (1-4) alkoxy- lation (C1-C4) products of such materials.

These other fatty acid partial esters, fatty alcohols and/or acids and/or esters thereof, and alkoxylated alcohols and those sorbitan esters which do not form optimum emulsions/dispersions can be improved by adding other di-long-chain cationic material, as disclosed hereinbefore, or other nonionic softener materials to achieve better results. The above-discussed nonionic compounds are correctly termed "softening agents," because, when the compounds are correctly applied to a fabric, they do impart a soft, lubricious feel to the fabric. However, they require a cationic material if one wishes to efficiently apply such compounds from a dilute, aqueous rinse solution to fabrics. Good deposition of the above compounds is achieved through their combination with the cationic softeners discussed hereinbefore and hereinafter. The fatty acid partial ester materials are preferred for biodegradability and the ability to adjust the HLB of the nonionic material in a variety of ways, e.g., by varying the distribution of fatty acid chain lengths, degree of saturation, etc., in addition to providing mixtures. (4) Optional Imidazoline Softening Compound Optionally, the composition can contain from about 1% to about 35%, preferably from about 5% to about 26%, of a di-substi- tuted imidazoline softening compound of the formula:

CH2 CH2

I I

N_^ N - R5 - γ2 - Rl (I)

C

R² or mixtures thereof, wherein Y² is as defined hereinbefore for the alkyl imidazolinium salts; Rl and R² are, independently, a C10-C22 hydrocarbyl group, preferably a C12-C18 alkyl group, most prefer- ably a straight chained tallow alkyl group. These di-substituted imidazoline compounds are believed to be biodegradable and susceptible to hydrolysis due to the ester group on the alkyl substituent. Furthermore, the imidazoline compounds contained in the compositions of the present invention are sus- ceptible to ring opening under certain conditions. As such, care should be taken to handle these compounds under conditions which avoid these consequences. For example, stable liquid compositions herein are preferably formulated at a pH in the range of about 1.5 to about 5.0, most preferably at a pH ranging from about 1.8 to 3.5. The pH can be adjusted by the addition of a Bronsted acid. Examples of suitable Bronsted acids include the inorganic mineral acids, carboxylic acids, in particular the low molecular weight (C1-C5) carboxylic acids, and alkylsulfonic acids. Suitable organic acids include formic, acetic, benzoic, methylsulfonic and ethylsulfonic acid. Preferred acids are hydrochloric and phos¬ phoric acids. Additionally, compositions containing these com¬ pounds should be maintained substantially free of unprotonated, acyclic amines.

(5) Optional Soil Release Agent Optionally, the compositions herein contain from 0% to about 10%, preferably from about 0.1% to about 5%, more preferably from about 0.1% to about 2%, of a soil release agent. Preferably, such a soil release agent is a polymer. Polymeric soil release agents useful in the present invention include copolymeric blocks of terephthalate and polyethylene oxide or polypropylene oxide, and the like. These agents give additional stability to the concen¬ trated aqueous, liquid compositions. Therefore, their presence in such liquid compositions, even at levels which do not provide soil release benefits, is preferred. A preferred soil release agent is a copolymer having blocks of terephthalate and polyethylene oxide. More specifically, these polymers are comprised of repeating units of ethylene and/or propylene terephthalate and polyethylene oxide terephthalate at a molar ratio of ethylene terephthalate units to polyethylene oxide terephthalate units of from about 25:75 to about 35:65, said polyethylene oxide terephthalate containing polyethylene oxide blocks having molecular weights of from about 300 to about 2000. The molecular weight of this polymeric soil release agent is in the range of from about 5,000 to about 55,000.

Another preferred polymeric soil release agent is a crystal- lizable polyester with repeat units of ethylene terephthalate units containing from about 10% to about 15% by weight of ethylene terephthalate units together with from about 10% to about 50% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight of from about 300 to about 6,000, and the molar ratio of ethylene terephthalate units to polyoxyethylene terephthalate units in the crystallizable polymeric compound is between 2:1 and 6:1. Examples of this polymer include the commercially available materials Zelcon® 4780 (from DuPont) and Milease® T (from ICI). Highly preferred soil release agents are polymers of the generic formula:

0 0 0 0 n n n ii

X-(OCH2CH2)_n(0-C-Rl-C-OR²)_u(0-C-Rl-C-0) (CH2CH2θ-)_n-X

in which X can be any suitable capping group, with each X being selected from the group consisting of H, and alkyl or acyl groups containing from about 1 to about 4 carbon atoms, preferably methyl, n is selected for water solubility and generally is from about 6 to about 113, preferably from about 20 to about 50. u is critical to formulation in a liquid composition having a rela¬ tively high ionic strength. There should be very little material in which u is greater than 10. Furthermore, there should be at least 20%, preferably at least 40%, of material in which u ranges from about 3 to about 5. The Rl moieties are essentially 1,4-phenylene moieties. As used herein, the term "the Rl moieties are essentially 1,4-phenyl- ene moieties" refers to compounds where the Rl moieties consist entirely of 1,4-phenylene moieties, or are partially substituted with other arylene or alkarylene moieties, alkylene moieties, alkenylene moieties, or mixtures thereof. Arylene and alkarylene moieties which can be partially substituted for 1,4-phenylene include 1,3-phenylene, 1,2-phenylene, 1,8-naphthylene, 1,4-naph- thylene, 2,2-biphenylene, 4,4-biphenylene and mixtures thereof. Alkylene and alkenylene moieties which can be partially sub¬ stituted include ethylene, 1,2-propylene, 1,4-butylene, 1,5-pen- tylene, 1,6-hexamethylene, 1,7-heptamethylene, 1,8-octamethylene, 1,4-cyclohexylene, and mixtures thereof.

For the Rl moieties, the degree of partial substitution with moieties other than 1,4-phenylene should be such that the soil release properties of the compound are not adversely affected to any great extent. Generally, the degree of partial substitution which can be tolerated will depend upon the backbone length of the compound, i.e., longer backbones can have greater partial sub¬ stitution for 1,4-phenylene moieties. Usually, compounds where the Rl comprise from about 50% to about 100% 1,4-phenylene moieties (from 0 to about 50% moieties other than 1,4-phenylene) have adequate soil release activity. For example, polyesters made according to the present invention with a 40:60 mole ratio of isophthalic (1,3-phenylene) to terephthalic (1,4-phenylene) acid have adequate soil release activity. However, because most polyesters used in fiber making comprise ethylene terephthalate units, it is usually desirable to minimize the degree of partial substitution with moieties other than 1,4-phenylene for best soil release activity. Preferably, the Rl moieties consist entirely of (i.e., comprise 100%) 1,4-phenylene moieties, i.e., each Rl moiety is 1,4-phenylene.

For the R² moieties, suitable ethylene or substituted ethylene moieties include ethylene, 1,2-propylene, 1,2-butylene, 1,2-hexylene, 3-methoxy-l,2-propylene and mixtures thereof. Preferably, the R² moieties are essentially ethylene moieties, 1,2-propylene moieties or mixture thereof. Inclusion of a greater percentage of ethylene moieties tends to improve the soil release activity of compounds. Surprisingly, inclusion of a greater percentage of 1,2-propylene moieties tends to improve the water solubility of the compounds. Therefore, the use of 1,2-propylene moieties or a similar branched equivalent is desirable for incorporation of any sub¬ stantial part of the soil release component in the liquid fabric softener compositions. Preferably, from about 75% to about 100%, more preferably from about 90% to about 100%, of the R2 moieties are 1,2-propylene moieties.

The value for each n is at least about 6, and preferably is at least about 10. The value for each n usually ranges from about 12 to about 113. Typically, the value for each n is in the range of from about 12 to about 43.

A more complete disclosure of these highly preferred soil release agents is contained in European Patent Application 185,427, Gosselink, published June 25, 1986, incorporated herein by reference.

(6) Optional Bacteriocides

Examples of bacteriocides used in the compositions of this invention are glutaraldehyde, formaldehyde, 2-bromo-2-nitropro- pane-l,3-diol sold by Inolex Chemicals under the trade name

Bronopol®, and a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazoline-3-one sold by Rohm and Haas Company under the trade name Kathon^® CG/ICP. Typical levels of bacteriocides used in the present compositions are from about 1 to about 1,000 ppm by weight of the composition.

Examples of antioxidants that can be added to the compo¬ sitions of this invention are propyl gallate, available from Eastman Chemical Products, Inc., under the trade names Tenox^® PG and Tenox S-l, and butylated hydroxy toluene, available from U0P Process Division under the trade name Sustane^® BHT.

(7) Other Optional Ingredients

Inorganic viscosity control agents such as water-soluble, ionizable salts can also optionally be incorporated into the compositions of the present invention. A wide variety of ion- izable salts can be used. Examples of suitable salts are the ha!ides of the Group IA and IIA metals of the Periodic Table of the Elements, e.g., calcium chloride, magnesium chloride, sodium chloride, potassium bromide, and lithium chloride. The ionizable salts are particularly useful during the process of mixing the ingredients to make the compositions herein, and later to obtain the desired viscosity. The amount of ionizable salts used depends on the amount of active ingredients used in the compositions and can be adjusted according to the desires of the formulator. Typical levels of salts used to control the composition viscosity are from about 20 to about 10,000 parts per million (ppm), prefer- ably from about 20 to about 4,500-5,000 ppm, by weight of the composition.

Alkylene polyammonium salts can be incorporated into the composition to give viscosity control in addition to or in place of the water-soluble, ionizable salts above. In addition, these agents can act as scavengers, forming ion pairs with anionic detergent carried over from the main wash, in the rinse, and on the fabrics, and may improve softness performance. These agents may stabilize the viscosity over a broader range of temperature, especially at low temperatures, compared to the inorganic electrolytes.

Specific examples of alkylene polyammonium salts include 1-lysine monohydrochloride and 1,5-diammonium 2-methyl pentane dihydrochloride.

The present invention can include other optional components conventionally used in textile treatment compositions, for example, perfumes, preservatives, optical brighteners, opacifiers, fabric conditioning agents, surfactants, stabilizers such as guar gum and polyethylene glycol, anti-shrinkage agents, anti-wrinkle agents, fabric crisping agents, spotting agents, germicides, fungicides, antioxidants such as butylated hydroxy toluene, anti-corrosion agents, other colorants or dyes, and the like.

In the method aspect of this invention, fabrics or fibers are contacted with an effective amount, generally from about 10 ml to about 150 ml (per 3.5 kg of fiber or fabric being treated) of the softener actives herein in an aqueous bath. Of course, the amount used is based upon the judgment of the user, depending on con¬ centration of the composition, fiber or fabric type, degree of softness desired, and the like. Preferably, the rinse bath contains from about 10 to about 1,000 ppm, preferably from about 50 to about 500 ppm, of the fabric softening compounds herein. Liouid Carrier The liquid carrier employed in the present invention is preferably water due to its low cost, relative availability, safety, and environmental compatibility. The level of water in the liquid carrier is more than about 50%, preferably more than about 80%, more preferably more than about 85%, by weight of the carrier. The level of liquid carrier in the composition is greater than about 50%, preferably greater than about 65%, more preferably greater than about 70%. Mixtures of water and up to about 15% low molecular weight, e.g., <100, organic solvent, e.g., lower alcohols such as ethanol, propanol, isopropanol or butanol are useful as the carrier liquid. Low molecular weight alcohols include monohydric, dihydric (glycol, etc.), trihydric (glycerol, etc.), and polyhydric (polyols) alcohols. In many cases, it is advantageous to use a 3-component composition comprising: (1) a diester quaternary ammonium cationic softener such as di(tallowoyloxy ethyl) dimethylammonium chloride; (2) a viscosity/dispersibility modifier, e.g., mono-long-chain alkyl cationic surfactant such as fatty acid choline ester, cetyl or tallow alkyl trimethylammonium bromide or chloride, etc., a nonionic surfactant, or mixtures thereof; and (3) a di-long-chain imidazoline ester compound in place of some of the DEQA. The additional di-long-chain imidazoline ester compound, as well as providing additional softening and, especially, antistatic bene- fits, also acts as a reservoir of additional positive charge, so that any anionic surfactant which is carried over into the rinse solution from a conventional washing process is effectively neutralized.

All percentages, ratios, and parts are by weight unless otherwise indicated. All numerical limits are normal approxi¬ mations. The following exemplify, but do not limit, the present invention. EXAMPLE I The following compositions show a decrease in fabric staining when added to the rinse cycle of an automatic laundry operation. Examples: Components

DTDMAC/MTTMAC* Blend (83%)

Ditallowalkyl Imidazoline Amide

Hydrochloric Acid (25%) Liquitint^® Patent Blue

Liquitint^® Royal Blue - 0.0040

Liquitint^® Blue 65

Kathon CG/ICP (1.5%)

Polydimethyl Siloxane Emulsion** (55%)

Perfume

CaCl2

Deionized Water

*Ditallowdimethylammonium chloride/monotallowtrimethyl- ammonium chloride. ^♦♦Polydimethyl siloxane emulsion is a mixture of several components available from Dow Corning Corp.

^♦Ditallowdimethylammonium chloride/monotallowtrimethyl- ammonium chloride.

^♦♦Polydimethyl siloxane emulsion is a mixture of several components available from Dow Corning Corp.

EXAMPLE II

*Dye levels adjusted to give a consumer acceptable color of approximate equal color intensity.

Claims

What is claimed is:

1. A fabric softening composition comprising:

(a) from 3% to 50% by weight of fabric softener, or mixtures thereof; and

(b) from 1 ppm to 1,000 ppm, preferably from 5 ppm to 250 ppm, of a stable dye system; wherein the dye system comprises a dye selected from the group consisting of:

1. Liquitint^® Blue HP;

2. Liquitint^® Blue 65;

3. Liquitint^® Experimental Yellow 8949-43;

4. Liquitint^® Green HMC;

5. Liquitint^® Patent Blue;

6. Liquitint^® Royal Blue;

7. Liquitint^® Teal;

8. Liquitint^® Violet;

9. Liquitint^® Yellow II; and 10. Mixtures thereof; and wherein the pH of the composition is from 1.8 to 6, preferably from 2 to 4.

2. The softening composition according to Claim 1 wherein the dye system comprises a dye selected from the group consisting of: Liquitint® Blue 65; Liquitint® Experimental Yellow 8949-43; Liquitint® Patent Blue; and mixtures thereof.

3. The softening composition according to Claim 1 wherein the dye is mixed with a conventional dye selected from the group consisting of:

1. Acid Red #1;

2. D&C Yellow #10;

3. Acid Blue #127:1; and

4. Mixtures thereof; wherein the ratio of Liquitint dye to conventional dye is from 1:1 to 1:0.1, preferably from 1:0.75 to 1:0.1, more preferably from 1:0.35 to 1:0.1. 4. The softening composition according to Claim 3 wherein Liquitint^® Patent Blue is mixed with D&C Yellow #10 at a ratio of from 1:0.75 to 1:0.25.

5. The softening composition according to Claim 3 wherein Liquitint^® Patent Blue is mixed with Acid Red #1 having a ratio of from 1:0.35 to 1:0.1.

6. The softening composition according to Claim 1 wherein Liquitint^® Patent Blue is mixed with Liquitint® Experimental Yellow 8949-43 at a ratio of from 1:1 to 1:1.5.