US3474038A - Detergent compositions containing n-(2-hydroxyalkyl)-omega-methyltaurine - Google Patents

Description

3,474,038 DETERGENT COMl-USITIQNS CONTAINDIG N-(2- HYDROXYALKYL)-w-METHYLTAURINE Ralph Raymond Sepulveda, Bronx, N.Y., and Frank Vincent Cieri, Union City, N.J., assignors to Lever Brothers Company, New York, N.Y., a corporation of Maine Filed Oct. 7, 1965, Ser. No. 493,804 Int. Cl. Clld 3/30, J/OZ, 1/38 US. Cl. 252-437 7 Claims ABSTRACT OF THE DISCLQSURE A novel liquid detergent is disclosed in which N-(2- hydroxyalkyD-N-methyl taurines are employed as hydrotroping agents. Organic sulfate, sulfonates, nonionic and cationic detergents can be prepared in homogeneous liquid formulations using the (I -C N-(2-hydroxyalkyl)- N-methyl taurines.

This invention relates to certain novel liquid detergent formulations.

The preparation of liquid detergents is a problem which has received considerable attention in the art. Generally, liquid detergents comprise the combination of a minor portion of a detergent ingredient and a major portion of water, the latter to provide liquidity. Further to supplement and to improve the detergent properties, it is common to include builders and foam improving agents. In the case of detergent composiitons designed for use in light-duty applications, organic compounds, such as the alkylamides or alkylolamides, are frequently used, usually to improve the forming properties. In the case of detergents adapted for use in heavy-duty applications, an inorganic builder is provided, which commonly is of the phosphate type, particularly, the alkali-metal tripolyphosphates and the alkali-metal pyrophosphates. In addition to the principal detergent, builders and suds boosters, other ingredients may be present in the liquid, such as viscosity controlling agents, soil-suspending agents, dyes, perfumes, colorants, optical brighteners, germicides, and the like, as well as salts present in the detergent as a result of the manufacturing process.

As is well known, a problem in the formulation of liquid detergents of the foregoing general description is obtaining a homogeneous liquid which is stable against separation into two or more liquid phases. The phase separation problem has been particularly troublesome. Reduced to its simplest terms, the problem is to dissolve a sufficient amount of the detergent-active ingredients in a single-phase liquid to provide a concentrate of adequate potency. The detergent components are frequently of limited solubility in water, and are liable to be salted Out by inorganic salts which may be present, such as the inorganic builders. In many liquid detergents, it is common to employ a minor amount of alcohol for the purpose of solubilizin the organic component in the water employed as the major portion of the solvent. In other liquid detergents, the lower alkyl-benzene sulfonates, such as sodium xylene sulfonate or sodium toluene sulfonates, have been used as hydrotropes.

According to the present invention, it has been found, surprisingly, that the salts of certain N-(2-hydroxyalkyl)- N-methyltaurines with water-solubilizing cations exhibit unexpected hydrotroping activity, and may be used for this purpose in detergent formulations.

Typical liquid detergent formulations to which the present invention is applicable consist essentially of about 2% to about 35% of a surface-active organic detergent and a sufficient amount of Water to liquefy the formulanite States Patent G 3,474,038 Patented Oct. 21, 1969 tion, the amount of the detergent being sufficient that a mixture having at least two liquid phases normally would occur. (By employing the phrase consisting essentially of it will be understood that detergent adjuncts may be present, such adjuncts being Well known in the art for modifying variou properties of the detergent formulation but not changing its essential detersive nature.) To such a detergent formulation is added from 2% to 35% of a C to C N (2 hydroxyalkyl) N-methyltaurine, the amount thereof relative to said detergent being sufficient to yield a homogeneous mixture.

The present invention is of particular applicability to detergent formulations consisting essentially of from 2% to 35% of a surface-active organic detergent, a builder to improve the detergency properties of said detergent and sufficient water to liquefy the formulation, the amount of the detergent being sufiicient normally to yield a formulation having more than one liquid phase. It has been found that the presence of a builder, and especially the inorganic alkaline phosphates, tends to make the organic detergents more difficultly soluble. As in the broad concept of the present invention, an amount of a C to C N-(2-hydroxyalkyl)-N-methyltaurine is present, generally etween 2% and 35% of the formulation, which is sufficient to render the liquid homogeneous. As a rule, when a builder is present, the ratio of N-(2-hydroxyalkyl)-N- methyltaurine to detergent necessary to obtain a homogeneous liquid is greater in the prescence of a builder than in its absence.

In greater detail, detergent formulations generally representative of the present invention will contain:

(a) from about 2% to about 35% of a surface-active, organic detergent compound selected from the group consisting of detergent salts of organic, sulfonic, and sulfuric acids, nonionic condensates of ethylene oXide having detergent properties and cationic detergent compounds containing a quaternary nitrogen atom in the molecule;

(b) from about 2% to about 35% of an N-(Z-hydroxyalkyl)-N-methyltaurine having from about 6 to 12 carbon atoms in the alkyl group, the Weight ratio of said N-(Z- hydroxyalkyl)-Nmethyltaurine to said detergent (a) being between about :10 and 10:90, and the amount of said N-(2-hydroxyalkyl)-N-methyltaurine being sufiicient to yield a homogeneous liquid;

(c) from 0% to about 20% of an alkaline phosphate builder;

(d) from 0% to about 15% of an organic amide of the formula:

0 R, H Rr-C-N in which R contains from about 8 to about 18 carbon atoms and R and R are each selected from the group consisting of hydrogen, lower alkyl and lower hydroxyalkyl radicals containing up to about 5 carbon atoms, there being no more than one hydrogen attached to the nitrogen; and

(e) water and miscellaneous ingredients, the balance to make In the foregoing formulation, as well as hereafter in the specification and claims, all percentages are based on the weight of the complete formulation unless specifically stated to the contrary.

Various miscellaneous ingredients may be added to improve the properties of the detergent formulation but which do not change the essential nature thereof. Usually not more than about 10% to 20% of the formulation will be composed of such ingredients; although larger amounts of miscellaneous ingredients may be present especially if the principal active ingredients contain significant amounts of more or less inert impurities. Possible miscellaneous ingredients include, but are not limited to, thickeners, fillers, soil suspending agents, dyes, perfumes, colorants, optical brighteners, germicides, opacifiers, and the like.

In the detergent formulations of the present invention, the amounts and relative proportions of detergents, builders and suds boosters will be suflicient to result normally in a multi-phase solution. Additionally, there is provided a hydrotroping agent which consists essentially of N-(Z-hydroxyalkyl)-N-methyltaurine in an amount, between about 2% and about 35% by weight of the finished detergent formulation, sufiicient to yield a homogeneous liquid. Generally there should be from 6 to 12 carbon atoms in the alkyl group of the N-(2-hydroxyalkyl) -N-rnethyltaurine. It is contemplated that the N-(Z-hydroxyalkyl)N-methyltaurines of the present invention may be used in combination with other hydrotropes. By the phrase consisting essentially of it is intended to include within the ambit of this invention combinations wherein the N-(Z-hydroxyalkyl)-N-methyltaurine is present in such an amount that but for its presence a multi-phase liquid would be obtained.

As the principal detergent, any one or more of the well-known surface-active detergent compounds may be used. Three important classes of detergents are recognized.

The first important class is the anionic detergents. Typical anionic detergents which may be used in the present invention are the salts of the water-solubilizing cations mentioned above with various organic acids containing from 8 to about 18 carbon atoms such as the sulfonates and sulfates. The hydrophobic portion of the molecule generally is characterized by at least one alkyl, alkenyl, alkylaryl or alkenylaryl radical containing between about 8 and 18 carbon atoms; however, this portion may also contain other functional groups such as carboxyl or ether groups.

A particularly important group of anionic detergents are those exhibiting good biodegradability. Generally the property of biodegradability is associated with linear fatty alkyl groups in the molecular structure.

The second class of useful detergents are the nonionic surface-active compounds. Nonionic detergents are generally prepared by the condensation of ethylene oxide with one or more organic compounds containing an active hydrogen. The commercially important nonionic detergents are generally condensates of ethylene oxide with either hydroxy-containing hydrophobic organic compounds, e.g. polypropylene glycol or fatty alcohols, or amino-containing organic compounds; however, many others have been proposed in the literature. Biodegradable nonionic detergents based on linear fatty alcohols are known and may be used in the present invention. As in the case of the anionic detergents, the organic compound may be either alkyl alkenyl, alkylaryl or alkenylaryl and contain other substituent groups, i.e. ether linkages such as in the polyoxypropylene-based compounds.

The third major class of detergents is the cationic detergents. These, in general, contain a quaternary nitrogen within the molecular structure. In some cases, the nitrogen may be contained in a ring structure.

The most important, and largest class of quaternary ammonium compounds are of the structure:

in which each of R R R and R is selected from the group consisting of hydrogen, alkyl radicals containing from 1 to 5 carbon atoms, alkyl and alkenyl radicals containing from 8 to about 18 carbon atoms and alkylaryl and alkenylaryl radicals containing from 8 to about 18 carbon atoms. Among R R R and R there should be between 1 and 3 high molecular weight groups (containing from 8 to about 18 carbon atoms). In the above formula X is a water-solubilizing cation of which many are known in the art. For example, the halides (especially Cl and Br), sulfates and methane sulfates are common; although other anions are possible and are included within the scope of the present invention.

The following is but a partial list of detergents which may be employed:

Sodium coconut sulfate,

Potassium stearyl sulfonate,

Potassium lauryl glycerol ether sulfate,

The ammonium of the sulfates of C14C18 mixed fatty alcohols,

Triethanolamine alkyl sulfate derived from coconut oil,

Sodium dodecyl benzene sulfonate,

Sodium C C secondary alcohol sulfates,

The potassium salts of carboxy isethionates, derived from coconut oil fatty acids,

Alkyl alcohol-3 ethylene oxide sodium sulfate,

Polyoxyethylene-polyoxypropylene ethanols,

Lauryl alcohol condensed with 6 moles of ethylene oxide,

Stearyl alcohol condensed with 10 moles of ethylene oxide,

C C mixed alkyl alcohols condensed with 9 moles of ethylene oxide,

Tall oil fatty acids condensed with ethylene oxide,

Ethylene diamine-propylene oxide-ethylene oxide condensates,

Dodecyl phenol-l0 ethylene oxide condensate,

Dodecyl trimethyl ammonium methosulfate,

Distearyl dimethyl ammonium chloride,

Dodecyl benzyl dimethyl ammonium bromide,

Cetyl pyridinium chloride.

The total amount of the detergent components will generally be between about 2% and about 35 by weight. The present invention is specifically concerned with formulations in which the concentration of the detergent is in excess of the amount which will dissolve in a single liquid phase in the absence of a solubilizing agent. It will be recognized by those skilled in the art that the solubility characteristics of the various surface-active detergent compounds vary, and are affected by the other materials present in the detergent formulation. In some instances it may be necessary to employ a solubilizing agent with as little as 2% of the second detergent present, especially if the formulation is built with an inorganic phosphate. In other cases, the detergent may be soluble to a considerably greater extent. Accordingly, the concentration of the detergent which will require the presence of a hydrotrope will depend on the nature of the detergent as well as the relative proportions of detergent and adjuncts.

The builders which are contemplated are the generally recognized soluble alkaline phosphates, such as the alkali metal, pyrophosphates and polyphosphates. Tetrasodium pyrophosphate, tetrapotassium pyrophosphate, sodium tripolyphosphate, potassium tripolyphosphates, and the simple sodium or potassium phosphates are the most common of the phosphate builders commercially available. The phosphate builders, when used, are commonly pres ent in a concentration of from 5% to 20%.

In addition to or in lieu of the phosphate builders, organic builders may be used. Certain of the organic amides mentioned below, for example, are well known to be effective builders. Nitriloacetic acid salts are another known group of organic builders which may be used in the present invention.

The organic amides contemplated have the following general formula:

R being a long-chain radical containing from about 8 to about 18 carbon atoms and R and R each being selected from the group consisting of hydrogen, lower alkyl and lower hydroxyalkyl. There should be no more than one hydrogen attached to the nitrogen atom. Typical compounds include, but are not limited to, coco diethanol amide, and lauric isopropanol amide. Commonly the amides are employed for the purpose of improving the foaming or detergency properties of the formulation. The organic amides, when used, are conventionally present in a concentration between about 2% and about 15%.

In addition to the foregoing principal ingredients of the composition, there may also be included the minor constituents typical of most detergent formulations. These minor constituents include thickeners, fillers, soil suspenders, dyes, optical brighteners, colorants, perfumes, germicides, etc. Sodium bicarbonate is Well-known as a thickener. Sodium and potassium chloride are also effective for this purpose. A number of cellulose derivatives, such as carboxymethyl cellulose, carboxyethyl cellulose, carboxyhydroxyethyl cellulose and the like are wellknown soil suspenders. Sodium silicates may be included, especially because of their value as corrosion retardants. Other constituents contemplated are the by-product salts which may be present as a result of the process by which the detergent is prepared. Most commonly these salts are the alkali metal or ammonium salts of the halogen acids or of sulfuric acid.

The salts of the N-(Z-hydroxyalkyl)-N-methyltaurines which are used as hydrotropes in the present invention have the following formula:

in which R; may contain from 4 to about carbon atoms, and M is a water-solubilizing cation. For most effective hydrotroping activity, the C -C N-(Z-hydroxyalkyl)- I-methyltaurine are preferred, (i.e. wherein R in the above formula contains from 4 to 8 carbon atoms). As is well known in the detergent art, the water-solubilizing cations normally are the alkali metal ions, ammonium, and substituted ammonium ions. For commercial economy and convenience, sodium, potassium and ammonium are the preferred cations. Typical substituted ammonium ions known in the art include trimethylamm'onium, triethanolammonium and morpholinium ions. The alkyl group of the N-(Z-hydroxyalkyl)-N-methyltaurines may be either straight or branched chain and may be derived from either synthetic or natural sources. Typical compounds include, but are not limited to the sodium salts of N-(Z-hydroxyalkyl)-N-methyltaurines, in which the radical R is C C or C or mixtures of the foregoing.

The amount of the N-(Z-hydroxyalkyl)-N-methyltaurine should be sufiicient to convert the detergent formulation into a homogeneous liquid stable against phase separation. Between 2% to 35% will usually be needed. The relative amount of the N-(Z-hydroxyalkyl)-N-methyltaurine to the second detergent may vary widely. In the broadest concept of this invention, a weight ratio between about 90:10 to 10:90 of N-(2-hydroxyalkyl)-N- methyltaurine to the second detergent will be used to obtain commercially useful improvements in the solubility of the detergent. For the most effective hydrotroping activity, a weight ratio of N-(Z-hydroxyalkyl)-N-methyltaurine to the second detergent between about 90: 10 and 50:50 is preferred.

Example 1 Percent Sodium salt of N (2 hydroxyoctyl) N methyl taurine 24 Sodium lauryl sulfate 6 Water 70 Example 2 Sodium salt of N (2 hydroxyoctyl) N methyl taurine 12 Sodium Alfol 14124.1 E.O. sulfate 18 Water 70 1A straight chain primary alcohol, obtained by liquid polymerization of ethylene, containing an average of 12 to lei: carbon atoms in the alkyl group and containing an average of about 3.1 ethylene oxide groups.

The formulations illustrated in Examples 1 and 2 are each clear homogeneous liquids.

As already mentioned, the compositions of the N-(2- hydroxyalkyl)-Nmethyltaurine (HAMT) plus a second detergent may be used in conjunction with various builders. Liquid detergent compositions illustrating the foregoing are as follows:

Example 3 Percent by Weight Ingredients A B 62.5. Description of composition Opaque liquid Clear homoslight organic geneous separation at liquid. surface of liquid.

B Sodium N-rnethyl-N-coconut acid taurate.

Example 4 Percent by Weight Ingredients A B Cm HAMT l- 8. Polypropylene benzene suli'onate a 2 2. Sodium tripolyphosphate..- 5.. 5. Water 93... 85. Description of composition Orga s Clear homoprecipitate geneous. from liquid.

a Mole weight of sulionic acid is 325.

Example 5 Percent by Weight Ingredients A B Cw HAMT 8 LHES l0... Tetra potassium pyrophosphate 20 Water 70 62.

Description of composition Transparent liquid, Clear LHES separates as homosolids at top and geneous within liquid. liquid.

' Sodium lauryl glycerol ether sulionate.

Example 6 Ingredients: Percent by wt.

Potassium dodecyl benzene sulfonate, alkane sulfonic acids 9.62 Sodium xylene-toluene sulfonate 7.93 Laurie isopropanolamide 3.11 Lauric diethanol amide 2.67 Tetrapotassium pyrophosphate 18.58

Water to 100%.

Example 7 Sufiicient N-(2-hydroxyalkyl)-N-methyltaurine is added to a mixture of 100 parts of the above liquid laundry detergent and about 5 parts of distearyl dimethyl ammonium chloride to yield a homogeneous liquid. Without N-(Z-hydroxyalkyl)-N-methyltaurine a multi-layer separation occurs.

Parts Ingredients A. B

Liquid laundry detergent 100 100 Cg HAMI Distearyl dimethyl ammonium chloride 5 5 Water 15 Description of composition Clear Multi-layer homm separation geneous liquid It will be understood that the examples are for illustrative purposes only and are not intended to limit the spirit or scope of the invention and claims herein.

We claim:

1. A liquid detergent composition consisting essen tially of:

(l) a water-soluble salt of an N-(Z-hydroxyalkyD-N- methyl taurine having from about 6 to about 12 carbon atoms in the alkyl group;

(2) a second organic surface-active material having detergent properties, said second detergent material being selected from the group consisting of detergent salts of organic sulfonic and sulfuric acids containing between about 8 and 18 carbon atoms, nonionic condensates of ethylene oxide having detergent properties and cationic organic compounds having detergent properties and containing a quaternary nitrogen atom in the molecule; and

(3) the balance of said composition consisting essentially of water in an amount sufficient to yield a liquid-detergent composition;

the amount of said second organic surface-active detergent material relative to the amount of said Water being sufiicient that a liquid detergent containing more than one phase would result in the absence of said -N-(Z-hydroxyalkyD-N-methyl taurine, and the amount of said N-(Z-hydroxylalkyl)-N-methyl taurine being between about 2% and about 35% by weight of said Water, and suflicient to yield a homogeneous liquid.

2. A liquid detergent composition consisting essentially of:

(1) an N-(Z-hydroxyalkyl)-N-methyl taurine having from about 6 to about 12 carbon atoms in the alkyl p;

(2) at least one second organic surface-active detergent compound selected from the group consisting of detergent salts of organic sulfonic and sulfuric acids, nonionic condensates of ethylene oxide having detergent properties and cationic organic compounds having detergent properties and containing a quaternary nitrogen in the molecule;

(3) a builder to improve the detergency of said second organic surface-active detergent compound; and

(4) the balance of said detergent composition consisting essentially of water in an amount suflicient to yield a liquid-detergent composition;

the amounts of said second organic surface-active detergent compounds and said builder, relative to the amount of said water, being sufiicient that a liquid detergent containing more than one phase would result in the absence of said N-(2-hydroxyalkyl)-N-methyl taurine, and the amount of said N- (2-hydroxyalkyl)-N-methyl taurine being between about 2% and about 35% by weight of said detergent composition, and sufiicient to yield a homogeneous liquid.

3. A liquid-detergent composition consisting essentially of:

(1) from about 2% to about 35% by weight of an N-(Z-hydroxyalkyl-N-methyl taurine having from about 6 to about 12 carbon atoms;

(2) from about 2% to about 35% by weight of at least one second surface-active organic detergent compound selected from the group consisting or detergent salts of organic sulfonic and sulfuric acids, nonionic condensates of ethylene oxide having detergent properties and cationic detergent compounds containing a quaternary nitrogen atom in the molecule;

(3) from about 0% to about 20% by weight of an alkaline phosphate builder;

(4) from about 0% to about 15% by weight of an organic amide of the formula in which R is a long chain acyclic aliphatic hydrocarbon radical having from 8 to about 18 carbon atoms, and R and R are each selected from the group consisting of hydrogen, lower alkyl and lower hydroxy alkyl radicals having up to about 5 carbon atoms, there being no more than 1 hydrogen attached to the nitrogen; and

(5) the balance of said composition consisting essentially of Water, the amount of said water being suiticient to yield a liquid formulation;

the amount of said second organic detergent compound, alkaline phosphate builder, when present, and organic amide, when present, being suflicient that a multiphase liquid detergent would result in the absence of said N-(Z-hydroxyalkyl)-N-methyl taurine, and the weight ratio of said N-(2-hydroxyalkyl)-N-methyl taurine to said second detergent (2) being between 10 and 10:90, and sufficient to yield a homogeneous liquid.

4. A detergent composition in accordance with claim 3 containing from about 2% to about 15% of said organic amide.

5. A detergent composition according to claim 3 containing from about 5% to about 20% of said alkaline phosphate builder.

6. A detergent composition according to claim 3 wherein the weight ratio of said N-(2-hydroxyalkyl-N-methyltaurine to said detergent is between about 90:10 and 50:50.

9 M) 7. A detergent composition according to claim 3 Where- FOREIGN PATENTS in said N-(2-hydroxya1kyl)-N-methyltaurine contains 1,332,754 6/1963 France from about 6 to about 10 carbon atoms in the alkyl group. LEON D. ROSDOL, Primary Examlner Refer n e Ci g 5 S. D. SCHWARTZ, Assistant Examiner UNITED STATES PATENTS U.S. Cl. X.R.

3,254,028 5/1966 Wixon 252137 252-438, 152; 260-513 Patent; BA 4,038 Dated: Qctober 21, 1969 Inventor(s) R R. Sepulveda et a1 It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

In the specification, column 1, line 3 "forming" should read "foaming".

In the claims, column 8, line 73, a parenthesis I: should be inserted after "(2-hydr'oxyalkyl".

bihiti) Mill SEALED FEB 1 71970 (SEAL) Atteat:

WILLIMI I. "S-GHUYLER, JR- Edmu member Oomissioner of Patents Atm tingOfficer

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