EP0076572B1

EP0076572B1 - Fabric softening detergent additive products and use thereof in detergent compositions

Info

Publication number: EP0076572B1
Application number: EP82304703A
Authority: EP
Inventors: John Robert Berschied, Jr.; John Albert Gregg
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1981-09-11
Filing date: 1982-09-08
Publication date: 1986-05-14
Also published as: EP0076572A1; JPS5874799A; CA1203651A; DE3271167D1

Description

This invention relates to compositions adapted to provide fabric softening effects in fabric laundering operations. More particularly it relates to the provision of softening and antistatic effects to fabrics while simultaneously cleansing fabrics by means of conventional synthetic detergent compounds and organic or inorganic detergent builders.
Fabric "softness" is an expression well defined in the art and is usually understood to be that quality of the treated fabric whereby the handle or texture is smooth, pliable and fluffy to the touch. Moreover, optimally softened fabrics are characterized by a desirable antistatic effect, which is exhibited by a lack of static cling.
It has long been known that various chemical compounds possess the ability to soften and impart antistatic benefits to fabrics. However, the effectiveness of any given compound may depend on its mode of use. For example, rinse-added fabric softeners, especially the quaternary ammonium compounds used in the detergent-free deep rinse cycle of a home laundering operation, provide exceptional conditioning benefits. Unfortunately, the cationic nature of these softeners causes them to interact undesirably with the common anionic surfactants such as the alkyl benzene sulfonates and is generally believed to preclude their use during the deterging cycle of a laundering operation involving commercial anionic detergents.
Numerous attempts have been made to formulate laundry detergent compositions that have both good cleaning properties and also textile softening properties so as to avoid the necessity of using a separate rinse-added textile softener product in addition to the usual laundry detergent.
The most commonly commercially available organic textile softening compounds are cationic materials that are reactive toward the anionic surfactants used in conventional laundry detergents. If both types of material are formulated in a single product, they tend to interact on addition to a wash liquor which results in undesirable effects such as increased soil redeposition on fabrics and poorer soil removal. A further consequence of this incompatibility is the inhibition of the tendency of the cationic material to deposit on the fabric surface and an associated reduction in the softening benefit delivered to the laundered fabric. In order to overcome this problem, compositions have been proposed which have sought to minimize the mutual reactivity of the anionic and cationic materials by the addition of compatibilizing compounds as described for example in US-A-3,886,075 and US-A-3,954,632.
An alternative approach has been to incorporate one of the reactant materials in a form that inhibits its contact with the other in the wash liquor and examples of this type of formulation are taught in US―A―3,936,537, US―A―3,644,203, and US―A―4,076,072. _
In an attempt to avoid the reactivity problem altogether, nonionic surfactants have been proposed in place of the conventional anionic surfactants and compositions of this type are described in, for example GB-A-1,079,388 and US-A-3,607,763.
EP-A-11333 on the other hand relates to a particulate detergent additive for softening textiles comprising a quaternary ammonium compound which has been precomplexed with an anionic complexing component.
Another proposal to provide acceptable cleaning and textile softening by avoiding the surfactant- softener interaction has been made in GB-A-1,514,276 which teaches the use of certain long chain tertiary amines that are nonionic in character at the wash liquor pH existing when a conventional laundry detergent is used. EP-A-11340 discloses cleaning and softening compositions comprising a combination of a long chain tertiary amine and a smectite-type clay in an anionic surfactant based detergent. The use of smectite-type clays as softening agents in detergent compositions is taught in GB―A―1,400,898. This type of softening agent does not affect the cleaning performances of the detergent composition but, if used on its own, requires a high level of incorporation for effective softening performance. US-A-4,292,035 discloses the formation of complexes of clay and organic textile softening agents for inclusion into detergent compositions for fabric softening.
In summary, there has been a continuing search for fabric conditioning agents which are compatible with anionic surfactants and which can be used without regard to the presence or absence of such materials. The current practice in providing a softening benefit to fabrics in domestic laundering operations continues to be to add a cationic fabric softener, either as a liquid to the final rinse of the washing process or as a separate additive to hot air tumble dryer.
It has now been found that detergent compositions can be formulated wherein the cleaning performance is not impaired together with effective textile softening performance.
It is an object of this invention to provide fabric conditioning particles for use in detergent compositions, which particles do not react with anionic surfactants and do deposit on fabrics to provide a softening benefit without the need of machine drying.
The present invention is based on the discovery that fabric softening particles prepared from certain comelted mixtures of dilong chain tertiary amines and quaternary ammonium salts can be included in a detergent composition to provide fabric softening benefits in a softening through-the-wash operation. The inclusion of the tertiary amine in the particles mitigates the interactive effects of the quaternary ammonium softening agents and further contributes to fabric softening, wherein the particles have a specified range of particle size, solubility in water and melting point. These particulate materials can be employed, either as additives to supplement conventional laundering products when the latter are added to the liquor or as part of a product designed to provide textile materials with simultaneous cleansing, and fabric softening effects.
According to one aspect of the invention there is provided a particulate additive product containing as essential ingredients a quaternary ammonium fabric softening agent in intimate mixture with a tertiary amine which provides further fabric softening and also acts as a dispersion inhibitor for the quaternary compound.
The present invention also encompasses, as integral formulations, compositions containing the materials defined herein in combination with synthetic detergent compounds and organic and inorganic builder salts. Such compositions, merely added to water, provide in a single step the provision of a laundering bath adopted to the provision of simultaneous cleansing and fabric softening effects. In this application, because of the small size of the particles of fabric softening agents, it is convenient to agglomerate the particles with water-soluble neutral or alkaline salts and certain clays to prevent segregation in the composition. The addition of clay is useful for preventing caking of the agglomerate during processing as well as providing further softening properties.

Summary of the invention

The present invention in its broadest aspect relates to a particulate detergent additive product in the form of fabric softening particles which are useful as adjuvants for detergent compositions. The invention also relates to agglomerated particulate detergent additive products and detergent compositions containing said particles.
The fabric softening particles, which are especially adapted for use in combination with anionic, nonionic, zwitterionic, and amphylytic surfactants, are intimate mixtures consisting of, by weight of the particles:

A. from 90% to 20% of a quaternary ammonium compound of the formula [R₁R₂R₃R₄N]⁺Y wherein at least one but not more than two of R,R₂R₃ and R₄ is an organic radical containing a group selected from a C₁₆ to C₂₂ aliphatic radical, or an alkyl phenyl or alkyl benzyl radical having 10 to 16 carbon atoms in the alkyl chain, the remaining group or groups being selected from C, to C₄ alkyl, C₂ to C₄ hydroxyalkyl, and cyclic structures in which the nitrogen atom forms part of the ring, Y constituting an equivalent amount of an anionic radical selected from hydroxide, halide, sulfate, methylsulfate, ethylsulfate, and phosphate ions; and
B. from 80% to 10% of a tertiary amine having the formula R,R₂R₃N wherein R, and R₂ are independently selected from C₁₀―C₂₂ alkyl or alkenyl groups, and R₃ represents a C₁―C₇ alkyl group, wherein substantially all the individual particles have a size in the range of 10 micrometers to 500 micrometers, a solubility in water of 50 ppm maximum at 25°C, and a softening point in the range of from 32.2°C (90°F) to 93.3°C (200°F).

The fabric softener particles consist of an intimate mixture of two components; a quaternary ammonium salt; and a di-long chain tertiary amine in a weight ratio range of from-9:1 to 1:4 respectively. Preferred ratios are from 4:1 to 1:2 and especially preferred ratios are from 3:2 to 2:3.
The fabric softening particles employed herein are in the form of substantially water-insoluble particles having an average size (diameter) range of from 10 micrometers to 500 micrometers. Preferably, the size of the particles herein lies in the range from 25 micrometers to 200 micrometers, more preferably from 50 micrometers to 100 micrometers, and particles within this range are efficiently entrained on fabric surfaces which is especially important for cool water washing and line drying. The water solubility of the particles must be no greater than 50 ppm at 25°C in water. The fabric softening particles must also be in the solid form in the washing liquor so that they deposit on the fabric as discrete particles. The particles therefore should have a melting point in the range of from 32.2°C (90°F) to 93.3°C (200°F)

The quaternary ammonium salt

Suitable quaternary ammonium compounds are included in US-A-3,936,537. The following description is an abbreviated discussion.
The quaternary ammonium salts useful herein have the formula [R₁R₂R₃R₄N]⁺Y wherein R₁ and preferably R₂, represent an organic radical containing a group selected from a C_l6--C₂₂ alkyl radical or an alkyl phenyl or alkyl benzyl radical having 10 to 16 carbon atoms in the alkyl chain, the remaining group or groups being selected from C,-C₄ alkyl, C₂-C₄ hydroxyalkyl, and cyclic structures in which the nitrogen atom forms part of the ring, and Y constitutes an equivalent amount of an anionic radical selected from hydroxide, halide, sulfate, methylsulfate, or ethylsulfate. The preferred anions for the quaternary ammonium fabric softener salts are chloride and methylsulfate.
The quaternary ammonium fabric softening compounds useful herein include both water-soluble and substantially water-insoluble materials. Imidazolinium compounds enumerated in US-A-3,936,537 possess appreciable water solubility and can be utilized in the present invention by mixing with the appropriate type and level of tertiary amine to give ultimate particle solubility in water of less than 50 ppm (parts per million) at 25°C. Relatively water-soluble quaternary fabric softeners can be used, such as diisostearyl dimethyl ammonium chlorides disclosed in US-A-3,395,100. Exemplary quaternary ammonium imidazolinium compounds are specifically methyl, 1-alkylamidoethyl, 2-alkyl imidazolinium methyl sulfates, more specifically 1-methyl-1[(tallowamido) ethyl]-2-tallowimidazolinium methyl sulfate. However, the most useful quaternary ammonium fabric softening agents are characterized by relatively limited solubility in water.
The quaternary ammonium fabric softening agents used in this invention can be prepared in various ways well known in the art. Many such materials are commercially available. The quaternaries are often made from alkyl halide mixtures corresponding to the mixed alkyl chain lengths in fatty acids. For example, the "ditallow" quaternaries are made from alkyl halides having mixed C14-C18 chain lengths. Such mixed di-long chain quaternaries are useful herein and are preferred from a cost standpoint.
The following are representative examples of substantially water-insoluble quaternary ammonium fabric softening agents suitable for use in the compositions and processes of the instant invention. All of the quaternary ammonium compounds listed can be formulated with the detergent compositions herein, but the compilation of suitable quaternary compounds hereinafter is only by way of example and is not intended to be limiting of such compounds. Dioctadecyldimethylammonium chloride is an especially preferred quaternary fabric softening agent for use herein by virtue of its high fabric softening activity; ditallowdimethyl ammonium chloride is equally preferred because of its ready availability and its good softening activity; other useful dilong chain quaternary compounds are dicetyldimethyl ammonium chloride; bis-docosyldimethyl ammonium chloride; ditallowdimethyl ammonium bromide; dioleoyl- dimethyl ammonium hydroxide; ditallowdimethyl ammonium chloride, ditallowdipropyl ammonium bromide; ditallowdibutyl ammonium fluoride, bis-[ditallowdimethyl ammonium]sulfate; tris-[ditallowdimethyl ammonium] phosphate; and the like.

The tertiary amine

The tertiary amines suitable for use in making the intimate particles have the general formula R,R_ZR₃N wherein R₁ and R₂ are independently selected from C₁₀ to C₂₂ alkyl or alkenyl groups, and R₃ represents a C₁ to C₇ alkyl. The tertiary amines are characterized by being water insoluble.
Exemplary tertiary amine compounds include, but are not limited to, the following: didecyl methylamine, dicoconut methylamine, dimyristyl methylamine, dicetyl methylamine, distearyl methylamine, diarachidyl methylamine, dibehenyl methylamine, di(mixed arachidyl/behenyl) methylamine, ditallowyl methylamine, and the corresponding ethylamines, propylamines, and butylamines. Especially preferred is ditallowyl methylamine.
It was discovered that the combination of the quaternary ammonium salt and the tertiary amine in intimate admixtures provide compositions that are effective in softening fabrics through-the-wash. The term "effective" means that the particles provide fabrics with a softer feel and an antistatic effect as described hereinabove. The tertiary amine, as shown by this invention, does protect the quaternary ammonium compound from interactive effects in the wash liquor and the admixture, in the form of particles, does deposit on the fabrics to condition the fabrics as described above.
The fabric softening particles of the present invention can be conveniently prepared by co-melting the tertiary amine and the quaternary ammonium salt compound and then converting the molten mass into particles of the desired size by any of the conventional means for converting melted materials to dry particles, e.g., cooling the molten mass, followed by grinding to the appropriate size, or simultaneously cooling the mass and forming particles by spraying the mass through a nozzle into a cool atmosphere (prilling). Particle size selection can be accomplished by controlling the process, or alternatively screening, air stream segregation, etc.
As disclosed herein, the particles can be added directly to a wash liquor containing a conventional detergent composition for softening fabrics through-the-wash. The particles can of course be dry-added to a granular detergent composition to provide a composition which can simultaneously clean and soften fabrics. To prevent segregation it is desirable to coat the particles to make agglomerates of the particles which will have approximately the same particle size as the granular detergent composition. The agglomerate can contain from 10% to 80%, preferably from 15% to 50%, more preferably from 20% to 40%, by weight, of the particles of quaternary ammonium salt and tertiary amine.
The fabric softener particles can be agglomerated by mixing with a water-soluble, neutral or alkaline salt and spraying the agitating mixture with water or an organic agglomerating agent. Further, certain smectite clays can be included which are useful as processing aids to prevent caking of the agglomerated during making. The smectite clays can provide additional fabric softening benefit when used in laundering fabrics wherein the water contains appreciable amounts of soluble calcium and magnesium salts, i.e., water having at least 153 mg CaC0₃/litre (9 grains per gallon) of such salts.
The water-soluble neutral or alkaline salt can be either organic or inorganic and has a pH in solution of seven or greater. The water-soluble neutral or alkaline salt will be employed in the agglomerated particulate in an amount from 10% to 80% by weight, preferably from 20% to 60% by weight, more preferably from 25% to 50% by weight, most preferably from 30% to 40% by weight. Specifically, some of the water-soluble, neutral or alkaline salts, if not used in the hydrated form, will absorb moisture during the processing of the agglomerated particulate detergent additive, and in addition function as detergency builders in wash water solutions.
Examples of such water-soluble neutral or alkaline salts include alkali metal chlorides such as sodium chloride and potassium chloride, alkali metal fluorides such as sodium fluoride and potassium fluoride, alkali metal carbonates such as sodium carbonates, alkali metal silicates, and mixtures thereof. Any conventional water-soluble, neutral or alkaline inorganic salt such as the alkali metal sulfates, notably sodium sulfate, may be employed in the present invention.
Water-soluble, neutral or alkaline salts also include the variety commonly known as detergency builder salts, especially alkaline, polyvalent anionic builder salts. Suitable detergency builder salts include polyvalent inorganic or organic salts or mixtures thereof. Suitable water-soluble, preferred inorganic alkaline detergency builder salts include alkali metal carbonates, borates, phosphates, polyphosphates, bicarbonates, silicates, and sulfates. Specific examples of such salts include the sodium and potassium tetraborates, perborates, bicarbonates, carbonates, tripolyphosphates, pyrophosphates, orthophosphates and hexametaphosphates.
Examples of suitable organic alkaline detergency builder salts are: water-soluble aminopolyacetates, e.g., sodium and potassium ethylenediaminetetraacetates, nitrilotriacetates and N-(2-hydroxyethyl)nitrilo- diacetates; water-soluble salts of phytic acid, e.g., sodium and potassium phytates; water-soluble polyphosphonates, including sodium, potassium, and lithium salts of ethane-1-hydroxy-1, 1-diphosphonic acid; sodium, potassium and lithium salts of methylene diphosphonic acid and comparable examples.
Additional organic builder salts are disclosed in US-A-2,264,103, US-A-3,308,067, and US-A-4,083,813. US-A-2,264,103 particularly discloses polycarboxylate and citrate salts, notably sodium citrate which may be used in the present invention as a water-soluble, alkaline salt. Further detergency builder salts are disclosed in US-A-3,936,537.
As noted hereinabove the water-soluble neutral or alkaline salt can be used as the agglomerating material with water above or with an organic agglomerating agent. The organic agglomerating agent can be present at levels, on a dry basis, of up to 20% by weight, preferably from 5% to 15% by weight, most preferably from 7% to 12% by weight of the particle agglomerate detergent additive.
The organic agglomerating agent (often loosely termed a "glue" or "glue mix") may include starches, notably the dextrin starches. Dextrin starches, or dextrins, are starches which are modified by heating in their natural state. Suitable dextrins include those manufactured by the A. E. Staley Manufacturing Company, Decatur, Illinois 62525 under the trade name Stadex (RTM) and described in the Staley Technical Bulletin TDS No. 116.
The Stadex (RTM) dextrins are produced by partially hydrolyzing corn starch, by heating in a dry atmosphere in the presence of acid. There are three main types, white dextrins, canary or yellow dextrins, and British Gums which are heated longer and catalyzed with little or no acid. The standard method of dextrin manufacture was roasting the starch in a horizontal cooker with agitation. However, Stadex (RTM) dextrins are made by "fluidizing" powdered starch during the heating cycle for greater conversion uniformity of starch to dextrin by ensuring a more even distribution of heat and acids.
Other examples of suitable dextrins and their preparation are contained in Starch and Its Derivatives by J. A. Radley, Chapman and Hall Ltd;, London (4th Ed. 1968), notably in the assay by G. V. Caesar on "Dextrins and Dextrinization" at pages 282-289 and the assay on "The Shardinger dextrins" at pages 290-305. Suitable examples of dextrins and their preparation are also contained in Chemistry and Industry of Starch by Ralph W. Kerr, Academic Press, Inc., New York (2nd Ed. 1950), particularly in the assay "Dextrinization" by G. V. Caesar at pages 345-355, and the assay "Manufacture of Dextrins" at pages 357-373.
Dextrin may be added to the agglomerate in a water solution. This dextrin-in-water solution may comprise from 10% to 60% by weight, preferably from 20% to 50% by weight, and most preferably from 30% to 40% by weight of dextrin.
Other exemplary materials useful as agglomerating agents are described in US-A-4,141,841. Briefly, these materials include polyethylene glycols and polypropylene glycols having a molecular weight of from 950 to 30,000; copolymers containing ethylene oxide and propylene oxide units, condensation products of one mole of a C₁₀ to C_ls saturated or unsaturated straight or branched chain carboxylic acid with from 20 to 50 moles of ethylene oxide, C₁₀-C₂₄ saturated or unsaturated, straight or branched chain alcohols with from 9 to 50 moles of ethylene oxide, certain polyoxyethylene glyceride esters and polyoxyethylene lanolin derivatives, amides which have a melting point between 30°C and 100°C, the condensation product of one mole of CS-C1s alkyl phenol with from 25 to 50 moles of ethylene oxide, C₁₂ to C₃₀ fatty acids which melt between 30°C and 100°C, and C₁₆ to C₃₀ fatty alcohols which melt at between 30°C and 100°C.
The agglomerated particulate detergent additive may optionally contain smectite clay as an ingredient. Clay compounds, namely sodium and calcium montmorillonites, sodium saponites, and sodium hectorites, can be incorporated into the agglomerated particulate detergent additive. These smectite clays may be admixed with the particulate detergent additive of this invention at levels from 5% to 50% by weight, preferably from 10% to 40% by weight, most preferably from 20% to 35% by weight, of the agglomerated particulate detergent additive. The clays used herein are "impalpable", i.e., have a particle size which cannot be perceived tactilely. Impalpable clays have particle sizes below 50 micrometers; the clays used herein have a particle size range of from 5 micrometers to 50 micrometers.
The clay minerals can be described as expandable, three-layer clays, i.e., aluminosilicates and magnesium silicates, having an ion exchange capacity of at least 50 meq/100 g. of clay and preferably at least 60 meq/100 g. of clay. The term "expandable" as used to describe clays relates to the ability of the layered clay structure to be swollen, or expanded, on contact with water. The three-layer expandable clays used herein are those materials classified geologically as smectites.
There are two distinct classes of smectite clays that can be broadly differentiated on the basis of the numbers of octahedral metal-oxygen arrangements in the central layer for a given number of silicon-oxygen atoms in the outer layers.
The clays employed in the compositions of the instant invention contain cationic counterions such as protons, sodium ions, potassium ions, calcium ions, and lithium ions. It is customary to distinguish between clays on the basis of one cation predominantly or exclusively absorbed. For example, a sodium clay is one in which the absorbed cation is predominantly sodium. Such absorbed cations can become involved in exchange reactions with cations present in aqueous solutions. A typical exchange reaction involving a smectite-type clay is expressed by the following equation: smectite clay (Na)⁺+NH₄OH⇄smectite clay-(NH₄)⁺+NaOH. Since the foregoing equilibrium reaction, one equivalent weight of ammonium ion replaces an equivalent weight of sodium, it is customary to measure cation exchange capacity (sometimes termed "base exchange capacity") in terms of milliequivalents per 100 g. of clay (meq/100 g.). The cation exchange capacity of clays can be measured in several ways, including by electrodialysis, by exchange with ammonium ion followed by titration or by a methylene blue procedure, all as fully set forth in Grimshaw, "The Chemistry and Physics of Clays", pp. 264-265, Interscience (1971).
The cation exchange capacity of a clay mineral relates to such factors as the expandable properties of the clay, the charge of the clay, which, in turn, is determined at least in part by the lattice structure, and the like. The ion exchange capacity of clays varies widely in the range from about 2 meq/100 g. of kaolinites to about 150 meq/100 g., and greater, for certain smectite clays. Illite clays although having a three layer structure, are of a nonexpanding lattice type and have an ion exchange capacity somewhere in the lower portion of the range, i.e., around 26 meq/100 g. for an average illite clay. Attapulgites, another class of clay minerals, have a spicular (i.e. needle-like) crystalline form with a low cation exchange capacity (25-30 q/100 g.). Their structure is composed of chains of silica tetrahedrons linked together by octahedral groups of oxygens and hydroxyl containing AI and Mg atoms.
It has been determined that illite, attapulgite, and kaolinite clays, with their relatively low ion exchange capacities, are not useful in the instant compositions. Indeed, illite and kaolinite clays constitute a major component of clay soils and, as noted above, are removed from fabric surfaces by means of the instant compositions. However, the alkali metal montmorillonites, saponites, and hectorites, and certain alkaline earth metal varieties of these minerals such as calcium montmorillonites have been found to show useful fabric-softening benefits when incorporated in compositions in accordance with the present invention. Specific examples of such fabric-softening smectite clay minerals are: sodium montmorillonite, sodium hectorite, sodium saponite, calcium montmorillonite, and lithium hectorite. Accordingly, smectite clays useful herein can be characterized as montmorillonite, hectorite, and saponite clay minerals having an ion exchange capacity of at least 50 meq/100 g., and preferably at least 60 meq/100 g.
The above discussion of optional clay additives is intended to only be a brief cursory review of the subject matter contained in US-A-3,936,537.
It is intended that the particulate detergent additive be incorporated in a detergent composition to provide cleaning and softening to fabrics. Because of segregation problems due to the small particle size of the particulate detergent additive, it is preferred to agglomerate said detergent additive as disclosed above. The detergent composition thus will contain an agglomerate of the particulate detergent additive dry admixed with the detergent composition which contains a surfactant and detergency builders. The detergent composition can contain from 5% to 50%, preferably from 10% to 30%, more preferably from 12% to 20%, by weight, of the agglomerated particulate detergent additive product.

Surfactant

The detergent composition which comprises the agglomerated particulate detergent additive additionally comprises from 5% to 85% by weight of surfactant selected from anionic, nonionic, ampholytic and zwitterionic surfactants, and mixtures thereof. Suitable surfactants are:

1. Anionic surfactants, having in their molecular structure an alkyl group containing from 8 to 22 carbon atoms and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl groups.) Examples of this group include C_a-C_1a alkyl sulfates, straight or branched chain alkylbenzene or alkyltoleune sulfonates containing from 9 to 15 carbon atoms in the alkyl chain (especially valuable are linear straight chain alkylbenzene sulfonates in which the average of the alkyl groups is about 11.8 carbon atoms and commonly abbreviated as C_11.8LAS), C₁₀ to C₂₀ alkyl ether sulfates having from 1 to 30 moles of ethylene oxide per molecule, sodium alkyl glyceryl ether sulfonates, ester of a-sulfonated fatty acids, and C₁₂ to C₂₄ olefin sulfonates.
2. Nonionic surfactants obtained by the condensation of 1 to 12 ethylene oxide moieties with a C₁₀ to C₁₈ aliphatic alcohol.
3. Zwitterionic surfactants such as 3 - (N,N - dimethyl - N - hexadecyl ammonio) - 2 - hydroxypropane - 1 - sulfonate and 3 - (N,N - dimethyl - N - tallowyl ammonio) - 2 - hydroxypropane - 1 - sulfonate.

Detergency builders

The detergent compositions of the instant invention contain a detergency builder in an amount from 5% to 85% by weight, preferably from 15% to 60% by weight, and most preferably from 20% to 40% by weight of the entire detergent composition. The detergency builders mentioned hereinabove are suitable for use in this invention.

Other optional ingredients

Other optional ingredients which may be included in the detergent composition include detergency builders enumerated in US-A-3,936,537 from column 13, line 54 through column 16, line 17, as well as antitarnish and anticorrosion agents, perfume and color additive, enzymes and other optional ingredients enumerated in US-A-3,936,537, from column 19, line 53 through column 21, line 21.

Method of preparation

The particulate detergent additive product is made by mixing the quaternary ammonium compound and tertiary amine by comelting the materials, cooling to a solid mass and obtaining the desired particle size by comminution and screening. An alternative method is to spray the liquid mixture through a pressure nozzle to form droplets of the desired size range which are then solidified by cooling and subject to screening (prilling process). It is a requirement of this invention that the quaternary ammonium compound and the tertiary amine be intimately mixed, i.e., comelted, in forming the particulate softening composition. The particle size range of the particulate detergent additive is from 10 to 500 micrometers, most preferably from 50 micrometers to 100 micrometers.
The processes of comminuting a solid mass of comelt such as grinding, ball milling, hammering, grating through a sieve etc. are well known in the art. Similarly, prilling processes are also well known.
It will be appreciated that in making the comelt, the materials should be low in solvent and ideally are substantially free thereof. While solvents, such as isopropanol, are conventionally present in commercially available quaternary softening materials to aid dispersion in aqueous media, such solvents are disadvantageous to the present invention in that the particles must have low solubility.
After initial combination of the quaternary ammonium compound and tertiary amine to form a comelt or prill of the desired particle size, said particles are agglomerated with the water-soluble neutral or alkaline salt for use as admixtures in detergent compositions and avoiding segregation. Agglomeration serves the purpose of combining the small particles to increase the apparent particle size without affecting the particle size of the individual particles. The salt also provides more strength to the agglomerate and makes the resulting mixture more free-flowing. In the wash liquor the water-soluble salt dissolves to release the individual particles which then are distributed throughout the wash liquor and are free to deposit on the fabrics being washed.
The mixture of comelt or prill and salt, preferably sodium carbonate or sodium tripolyphosphate, is fed into a highly efficient mixer where agglomerating agent (dextrin glue solution) is sprayed onto the mixture. Types of mixers which may be employed include the Schugi mixer (Flexomix (RTM) 160, 250, 335 or 400), the O'Brien mixer, the Littleford mixer, the Patterson-Kelly mixer, ribbon mixers, and/or vitually any of the conventionally-known pan agglomerators. This results in agglomerates of water-soluble, neutral or alkaline salt and prills or comelt of quaternary ammonium compound and tertiary amine in the same size range as conventional detergent granules, thus eliminating the problem of segregation (150-1190 micrometers in size). The final agglomerates are discharged from the (Schugi) mixer and optionally admixed with particulate, smectite clay. The resulting composition is aged for approximately one hour, optionally mixed with silica if increased flowability is desired, and admixed with conventional detergent granules.
Certain of the water-soluble, neutral or alkaline salts may absorb moisture during the processing of the agglomerate. In addition, some of the water-soluble neutral. or alkaline salts function as detergency builders in wash water. Further, the mixture of prills and water-soluble neutral or alkaline salt, when agglomerated, provides increased fabric softening relative to prills alone in the second wash load.

Example I

A particulate detergent additive was prepared as follows:
The quaternary (DTDMAC) and amine (DTMA) were melted together to form a clear solution in a steam bath. The molten mixture was cooled and became solid at room temperature. The solid mass was broken up and then ground in a mortar with a pestle to a particle size in the range not greater than 65 micrometers to 80 micrometers. A microscope with a grid was used to check the particle size during the grinding. (A convenient alternative process would be to make the particles by a prilling process). The softening point of the particulate detergent additive was about 40.6°C (105°F). The particles were essentially insoluble in water at 25°C. The particulate detergent additive in all the subsequent examples had essentially the same solubility characteristics and ranged in melting point from 32.2°C (90°F), to 57.2°C (135°F), depending on the ratio of the components.
The particulate detergent additive can be added to a wash liquor to provide softening to fabrics. As defined hereinabove softening means that the fabrics treated therewith have a softer feel to the touch and exhibit a lack of static cling.
Comparable results are obtained when the quaternary ammonium compound utilized is ditallowdimethyl ammonium methylsulfate, ditallowdimethyl ammonium ethylsulfate, 1-methyl-1-[(tallowamido)-ethyl]-2-tallow imidazolinium methylsulfate, or mixtures thereof in place of the ditallowdimethyl ammonium chloride on a part for part basis.
Substantially similar results are obtained when the ditallow methylamine is replaced with didecyl heptylamine, dicoconut butylamine, dimyristyl ethylamine, dicetyl methylamine, diarachidyl methylamine, dibehenyl methylamine, and di(mixed arachidyl/behenyl) methylamine.

Example II

The particulate detergent additive particles made in Example I were agglomerated with sodium tripolyphosphate (STP), in a cement mixer. The STP was a dry, anhydrous, powder with at least 90% passing through a 0.149 mm (100 mesh Tyler) sieve.
To 33.75 parts of particles made in Example I were added 28.95 parts of STP and sprayed with 8.42 parts of dextrin glue (35 parts solid to 65 parts water). This resulted in agglomerates of the particulate detergent additive and STP having the same size range as other detergent granules, 150-1190 micrometers.
The product of this agglomerating step was added to detergent granules to provide a composition which simultaneously cleaned and softened fabrics. The agglomerated fabric softening or conditioning composition provided better second load fabric softening than the addition of the particulate detergent additive alone to wash water.
As mentioned hereinbefore smectite clay can be a component of the agglomerate. The process is one of simply admixing the agglomerate with the appropriate amount of impalpable smectite clay. For example 71.1 parts of the agglomerate was admixed with 29.9 parts of calcium montmorillonite clay of good fabric softening performance and having an ion exchange capacity of about 84 meq./100 g. (available from Industrial Minerals Ventures Inc. U.S.A., sold under the trade name Imvite (RTM) K).
Substantially similar results are obtained when sodium tripolyphosphate is replaced with sodium tetraborate, potassium tetraborate, sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, potassium tripolyphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium hexametaphosphate, potassium hexametaphosphate, sodium sulfate, potassium sulfate, sodium citrate, potassium citrate, and mixtures of these water-soluble, alkaline salts.
Other types of smectite clay which when substituted for calcium montmorillonite yield comparable fabric-softening performance include sodium hectorite, sodium saponite, calcium montmorillonite, lithium hectorite, and mixtures thereof.

Example III

Particulate detergent additives and agglomerates thereof made according to Examples I and II were added to detergent granules to make detergent compositions which provide cleaning and softening through-the-wash and evaluated for cleaning and softening performance relative to a detergent composition having no softening attribute and a second composition having a softening component outside this invention.
The composition of the softener components were as follows:
Control 1 does not contain any fabric softening component; Control 2 contains 8% of a mixture of tertiary amines (2:1 DTMA: Dicoconut methylamine) and 12% of clay. The softener component of Composition No. 1 was added to the detergent component as an agglomerate having the composition shown. In Composition No. 2 the softener component is an admix of the product made in Example I.
Several fabrics were washed with the detergent compositions in a 10 minute wash at 21.1°C (70°F) in soft water (51 mg CaC0₃/litre: 3 grains hardness/gal), line dried, air tumbled in a dryer without heat for 10 minutes, and checked for total voltage using a Faraday cage, instances of static cling of the fabrics, and for softness by a panel in paired comparison testing.
Static Test Results (20°C:68°F/34% Rel. H.)
Softening Performance-Panel Score Units
As shown by the results, Compositions No.'s 1 and 2, which are within the scope of this invention, provide a softening effectto fabrics relative to Control 1 and the softening effect is superiorto that provided by Control 2 which contains a mixture of tertiary amines.
In Composition No. 1 when sodium tripolyphosphate or sodium tetraborate replaced the sodium carbonate as the soluble salt in the agglomerated particulate detergent additive substantially similar results were observed.
'In Composition No. 1 when the 2:3 ratio of DTDMAC:DTMA was replaced by a 3:2 ratio of DTDMAC:DTMA substantially similar results were observed.
In Composition No. 1 when the 2:3 ratio of DTDMAC:DTMA was replaced by a 1:4 ratio of DTDMAC:DTMA the softening benefit observed was less than Composition No. 1 and about equal to Control 2.
In Composition No. 1 when the 2:3 ratio of DTDMAC:DTMA is replaced by a 9:1 ratio of DTDMAC:DTMA substantially similar results were observed.
Comparable results are obtained when the sodium carbonate in the agglomerated particulate detergent additive of Composition No. 1 is replaced by sodium tripolyphosphate, sodium tetraborate, potassium tetraborate, sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, potassium tripolyphosphate, sodium pyrophosphate, potassium pyrophosphate, sodium hexametaphosphate, potassium hexametaphosphate, sodium sulfate, potassium sulfate, sodium citrate, potassium citrate, and mixtures of the water-soluble, alkaline salts.
Comparable results are obtained when the quaternary ammonium compound utilized is ditallowdimethyl ammonium methylsulfate, ditallowdimethyl ammonium ethylsulfate, 1-methyl-1-[(tallow amido) ethyl]-2-tallow imidazolinium methyl sulfate, or mixtures thereof in place of the ditallowdimethyl ammonium chloride on a part for part basis.
Comparable results are obtained when the DTMA in the agglomerated particulate detergent additive is replaced by didecyl methylamine, didecyl heptylamine, dicoconut methylamine, dicoconut butylamine, dimyristyl methylamine, dimyristyl ethylamine, dicetyl methylamine, diarachidyl methylamine, dibehenyl methylamine, and di(mixed arachidyl/behenyl) methylamine.
Since the intimate mixture of quaternary ammonium salt and tertiary amine particles are essentially water-insoluble, even under alkaline conditions, they are wholly compatible with all manner of detersive surfactants and detergency builders. Thus, the detergent component in Composition No. 1 can include any of the surfactants and builders disclosed hereinabove and still deliver the softening to fabrics through-the-wash provided by the agglomerated particulate detergent additive.
Compositions 1 and 2 show that the insoluble, small particles of the intimate mixture of quaternary ammonium salt and tertiary amine do deposit on fabrics during washing to provide a softening benefit to the fabrics, merely with line drying. The softening benefit delivered to the fabrics will be greater when the washed fabrics are machine dried with heat which melts the particles on the fabric and provides a better coating to the fibers.

Claims

1. A particulate detergent additive product adapted to soften textiles when applied thereto from a detergent wash liquor, the additive product being in the form of particles comprising by weight thereof:

A. from 90% to 20% of a quaternary ammonium salt having the formula [R₁R₂R₃R₄N]⁺Y wherein at least one but not more than two of R₁R₂R₃ and R₄ is an organic radical containing a group selected from a C₁₆ to C₂₂ aliphatic radical or an alkyl phenyl or alkyl benzyl radical having 10 to 16 carbon atoms in the alkyl chain, the remaining group or groups being selected from C, to C₄ alkyl, C₂ to C₄ hydroxyalkyl, and cyclic structures in which the nitrogen atom forms part of the ring, Y constituting an equivalent amount of an anionic radical selected from hydroxide, halide, sulfate, methylsulfate, ethylsulfate, and phosphate ions;

wherein substantially all the individual particles have a size in the range of 10 micrometers to 500 micrometers, a solubility in water of 50 ppm maximum at 25°C, and a softening point in the range of from 32.2°C (90°F) to 93.3°C (200°F), characterized in that the particulate product is an intimate mixture consisting of the quaternary ammonium salt and

B. from 80% to 10% of a tertiary amine having the formula R₁R₂R₃N wherein R, and R₂ are independently selected from C₁₀―C₂₂ alkyl or alkenyl groups, and R₃ represents a C₁―C₇ alkyl group.

2. An agglomerated particulate detergent additive product adapted to soften textiles when applied thereto from a detergent wash liquor, characterized in that said product is an agglomerate of:

A. from 10% to 80%, preferably from 15% to 50%, more preferably from 20% to 40%, by weight of the particles of Claim 1;

B. from 10% to 80%, preferably from 20% to 60%, more preferably from 25% to 50%, by weight of a water-soluble, neutral or alkaline salt; and

C. from 0% to 20% by weight of an organic agglomerating agent; and wherein the agglomerate is from 150 to 1190 micrometers in size.

3. A product according to Claim 1 or 2 characterized in that substantially all the particles of the additive product of Claim 1 are from 25 to 200 micrometers, preferably from 50 to 100 micrometers in size.

4. A product according to Claim 2 or 3 characterized in that the water-soluble, neutral or alkaline salt is selected from alkali metal salts of carbonates, tetraborates, orthophosphates, polyphosphates, bicarbonates, silicates, sulfates, citrates, and mixtures thereof.

5. A product according to any of Claims 1 to 4 characterized in that the quaternary ammonium compound is selected from ditallow dimethylammonium chloride, ditallow dimethylammonium methylsulfate, 1 - methyl -1 - [(tallowamido)ethyl] - 2 - tallowimidazolinium methylsulfate, and mixtures thereof.

6. A product according to any of Claims 1 to 5 characterized in that the tertiary amine is selected from ditallow methylamine, dicoconut methylamine, dicetyl methylamine, distearyl methylamine, diarachidyl methylamine, dibehenyl methylamine, and mixtures thereof.

7. A product according to any of Claims 1 to 6 characterized in that the weight ratio of quaternary ammonium compound to tertiary amine is from 4:1 to 1:2, preferably from 3:2 to 2:3.

8. A product according to any of Claims 2 to 7 characterized by from 5% to 15% by weight of an organic agglomerating agent selected from dextrin, a solution of dextrin in water, polyethylene glycol, polypropylene glycol, the condensation product of one mole of carboxylic acid having from 10 to 18 carbon atoms with from 20 to 50 moles of ethylene oxide, the condensation product of one mole of alcohol having from 10 to 24 carbon atoms with from 9 to 50 moles of ethylene oxide, polyoxyethylene glyceride, polyoxyethylene lanolin derivative, amide, and the condensation product of one mole of alkyl phenol having an alkyl chain from 8 to 18 carbon-atoms with from 25 to 50 moles of ethylene oxide, and mixtures thereof.

9. A product according to any of Claims 2 to 8 characterized in that the agglomerated particulate detergent additive product is additionally admixed with from 5% to 50%, preferably from 10% to 40%, more preferably from 20% to 35%, by weight of a smectite clay having an ion exchange capacity of at least 50 meq/100 g, preferably at least 60 meq/100 g.

10. A detergent composition for softening fabrics laundered therewith comprising:

(1) from 5% to 85% by weight of surfactant selected from anionic, nonionic, ampholytic, and zwitterionic surfactants, and mixtures thereof and

(2) from 5% to 85% by weight of detergency builder, characterized in that it further contains

(3) from 5% to 50% by weight of an agglomerated particulate detergent additive according to any of Claims 2 to 9.