WO1992022535A1

WO1992022535A1 - Fabric softening agents and compositions thereof

Info

Publication number: WO1992022535A1
Application number: PCT/US1992/004905
Authority: WO
Inventors: Michael Peter Siklosi; Charles Albert Hensley
Original assignee: The Procter & Gamble Company
Priority date: 1991-06-19
Filing date: 1992-06-11
Publication date: 1992-12-23
Also published as: PT100612A; IE921974A1; NZ243195A; TW213964B; CN1069788A; MX9203013A; TR25990A; AU2266592A

Abstract

This invention relates to a non-stoichiometric bisimidazoline ion pair complex. The ion pair complex comprises a bisimidazoline, organic acids selected from alkyl and aryl carboxylic acids, alkyl and alkyl aryl sulfonic acids, and alkyl dicarboxylic acids, and Bronstedt acids. The ion pair complex thus obtained can be concentrated and still retain softening performance benefits over many known conventional softeners. The ion pair complex can be combined with cosofteners in an aqueous fabric softening composition used to treat fabrics, usually during the rinse cycle of laundering operations.

Description

FABRIC SOFTENING AGENTS AND COMPOSITIONS THEREOF

Tpr.hnical Field

This invention relates to bisimidazoline ion pair complexes which are used as fabric softening agents. The ion pair complexes are used with or without cosoftening agents usually in an aqueous fabric softening composition to treat fabrics during the rinse cycle of laundering operations. The composition can be substantially concen¬ trated.

Background

Liquid fabric softening compositions have long been known in the art and are widely utilized by consumers during the rinse cycles of laundry operations. To satisfy the consumer's need for convenience and the growing environmental concerns, there is an increasing need for fabric softening agents that can be used in concentrated formulas with equivalent softening performance. This invention discloses fabric softening agents which have excellent softening performance, and which can be formulated into a substantially concentrated aqueous fabric softening composition.

Fabric softeners impart a smooth, pliable, and fluffy texture to laundered fabrics. Consumers tend to prefer fabric softeners which give more softness. The term "fabric softening" as used herein and as known in the art refers to a process whereby a desirably soft and fluffy appearance is imparted to fabrics. The practical methods of how to measure softness are explained in the examples.

Conventionally, rinse-added fabric softening compositions contain, as the active component, substantially water-insoluble cationic materials having two long alkyl chains. Typical of such materials ar ditallow dimethyl ammonium chloride, and imidazoliniu complexe substituted with two tallow groups. Other compounds known for having excellent softening performance are bisi idazolines. These compounds are disclosed in U.S. Patents 3,855,235 (issued Dec. 17, 1974), 3,887,476 (issued June 3, 1975), and 3,898,244 (Aug. 5, 1975). However, these bisimidazoline compounds are highly viscous even in conventionally prepared products, and thus difficult to incorporate into concentrated products. The term "conventional product" refers to fabric softening products having about 5% to 8% active softening agent concentration, whereas "concentrated product" has higher concentrations, usually 2 to 3 times this level.

In recent years, consumers have tended to prefer liquid fabric softeners which are highly concentrated because these products take less space, are easy to carry, and concentrated packaging contributes to decreasing of solid waste. Solid waste has become a critical requirement of consumer products. However, due to the physical properties of fabric softening agents, concentrating these agents often results in a highly viscous liquid which is difficult to measure, pour, and is often unstable on storage. Moreover, the gel-like appearance of a thick product is unacceptable to consumers. The main difficulty of formulating an acceptable product is to disperse the active agents. Numerous attempts have been made to overcome this problem, such as using more dispersible fabric softening agents, using dispersing solvents, adding viscosity controlling agents, etc.. Another method is to "ion pair" the fabric softening agent, forming a complex which is easily dispersed in water. The term "ion pair" is used for situations where the fabric softening agents, usually amines, are dispersed with any kind of anion such as surfactant fatty acids, thus creating an ammonium/anion pair.

British Patent Application Nos. 1,077,103 and 1,077,104, assigned to Bayer, published July 26, 1967, disclose amine-anionic surfactant ion pair complexes useful as antistatic agents. These complexes are applied directly to the fabric from an aqueous carrier. Fatty acid-amine ion pair complexes in granular detergents are disclosed in European patent application No. 133,804, Burckett-St. Laurent et al., published June 3, 1984.

More recently, U.S. Patent No. 4,756,850 (issued July 12, 1988) discloses dryer-added fabric conditioning articles and methods utiliz¬ ing imidazoline-anionic surfactant ion pair complexes as fabric condi¬ tioning agents. The composition containing these actives are commin¬ gled with the fabrics and provide a soft, antistatic finish concurrent¬ ly with the drying operation. U.S. Patent No. 4,915,854 (issued Apr. 10, 1990) discloses an amine-anionic compound ion pair complex particles having an average particle diameter of from about 10 microns to about 300 microns. These particles provide excellent through-the-wash softening without signifi¬ cantly impairing cleaning performance. Furthermore, U.S. Patent No. 4,915,854 discloses that ion pair particles which are made from lower chain length amines impart improved processing characteristics and improved chemical stability in liquid detergents.

U.S. Patent Nos. 4,844,824 (issued July 4, 1989) and 4,861,502 (issued Aug. 29, 1989) teach other variations of amine-organic anion ion pair complexes useful as through-the-wash fabric conditioning agents.

These ion pairs are basically stoichiometric; i.e., the amine and anion pairs are on a 1:1 basis.

Surprisingly, it has now been found that a unique non-stoichio- metric ion pairing method solves the dispersing problem and, by apply¬ ing this non-stoichiometric ion pairing to the bisimidazoline fabric softening compounds, a fabric softening active that can be substantially concentrated and still retaining softening performance benefits over many known conventional softeners is obtained. It is an object of the present invention to provide fabric soften¬ ing agents which have excellent fabric softening performance as well as favorable physiological properties to formulate a concentrated product. It is also an object of the present invention to prepare a fabric softening composition with or without cosofteners which is found acceptable to consumers. A further object of the invention is to provide a practical and efficient process to obtain this ion pair complex and compositions including the ion pair complex. Summary of the invention The present invention relates to an ion paired complex comprising;

A. A bisimidazoline of the formula;

(CH₂)2 (CH₂)2

/ \ / \

N N-(CH2)_n-N N \\ / \ //

C C

I I

Rl Rl wherein n is 2 - 4 and Rl is independently selected from C6-22 alkyl groups;

B. Organic acids selected from the group consisting of carboxylic acids having a C6-22 alkyl or C7-C22 alkyl aryl chain, alkyl or alkyl aryl sulfonic acids having a Ci-22 alkyl chain, dicarboxylic acids having a C2-C8 alkyl chain, and mixtures thereof;

C. Bronstedt acids having a pKa value of not greater than 6, provided that the pH of a dispersion of the acid is not greater than 5;

and wherein the mole ratio of components A : B : C is from about 1.0 : 1.8 : 1.4 to about 1.0 : 0.1 : 2.0 when component B is a onoacid and 1.0 : 0.9 : 1.4 to about 1.0 : 0.1 : 2.0 when component B is a diacid.

The ion pair complex is included in an aqueous fabric softening composition at a concentration up to about 23%, wherein optionally viscosity controlling agents are added to the composition. The ion pair complex can be mixed with cosofteners to provide a composition with excellent fabric softening performance wherein the bisimidazoline in the ion pair complex is more than 25% by weight of the total softening active agents. Detailed description of the invention

The components of the unique non-stoichiometric ion pair complex and the method of ion pairing of the present invention are described in detail below. Further described are the preferred compositions for the ion pair complex as fabric softening agents and optional ingredients such as cosofteners.

Component A The bisimidazoline compounds can be prepared by the reaction of a higher fatty acid with a polya ine. Such polyamines are those having the following structural formula; NH2CH2CH2NH(CH2)_nNHCH2CH2NH2 wherein n is 2 - 4, preferably 2. The preferred polyamine is triethylenetetra ine. The bridge portion (CH2)n of the bisimidazoline compound should not be longer than propyl, for longer chains are thought to cause physicochemical property problems. The bridge also should not include nitrogen (N), for those derivatives are thought to cause yellowing when applied to fabrics.

The Rl substituent of the respective imidazoline rings represents the alkyl group attached to the carboxyl group of the fatty acid from whence it is derived. Accordingly, when a mixture of fatty acids is used, the R¹ substituent collectively represents the mixture of alkyl residues associated with carboxyl groups of said fatty acids.

With respect to the applicable fatty acid reactants, those with C6-22 alkyl groups are suitable for preparing the bisimidazoline com¬ pounds useful in the practice of this invention. Representative of such fatty acids include; caproic, caprylic, capric, lauric, myristic, yristoleic, palmitic, pal itoleic, stearic, oleic, elaidic, ricinoleic, linoleic, linolenic, eleostearic, arachidonic, behenic, and erucic acid. The fatty acids can be derived from naturally occurring or synthetic fatty acids. Suitable sources of naturally occurring fatty acids include tallow fatty acids, corn oil fatty acids, cottonseed oil fatty acids, peanut oil fatty acids, soybean oil fatty acids, canola oil fatty acids (i.e. fatty acids derived from low erucic acid rapeseed oil), sunflower seed oil fatty acids, sesame seed oil fatty acids, safflower oil fatty acids, palm kernel oil fatty acids, palm oil fatty acids, and coconut oil fatty acids. The fatty acids can be saturated or unsaturated, including positional or geometrical isomers, e.g., cis- or trans-isomers.

Preferred fatty acids are oleic acid, tallow acid, hardened tallow acid and mixtures thereof. The fatty acid reactant can take the form of a free fatty acid, an alkyl ester thereof or the naturally occurring glyceride esters. As will be noted below, the glyceride ester form of the fatty acid will readily split in the course of the initial condensation of the acid and the polyamine reactant and the glycerol by-product can be removed from the reaction mixture.

The following are nonlimiting examples of specific triglycerides which can be used to prepare the bisimidazolines of this invention: Animal fats such as lard, tallow, oleo oil, oleo stock, oleo stearin and the like, which are solid at room temperature can be utilized as a mixture with liquid oils. Also, liquid oils, e.g., unsaturated vegetable oils, can be used. These oils can be partially hydrogenated to convert some of the unsaturated double bonds of the fatty acid constituents into saturated bonds. Vegetable oils include unhydrogenated or partially hydrogenated soybean oil, hazelnut oil, linseed oil, olive oil, peanut oil, canola oil, coconut oil, safflower oil, rapeseed oil, cottonseed oil, corn oil and sunflower seed oil can also be used herein. Solid vegetable oils useful herein include palm oil, palm kernel oil, cocoa butter and hydrogenated vegetable oils.

Also suitable for use herein are the so-called low molecular weight synthetic fats which are certain tri- or diglycerides in which one or two of the hydroxyl groups of the glycerine have been esterified with acetic, propionic, butyric or caprionic acids and one or two of the remaining hydroxyl groups of the glycerine have been esterified with higher molecular weight fatty acids having from 12 to 22 carbon atoms. Other common types of triglycerides include: cocoa butter and cocoa butter substitutes, such as shea and illipe butter; milk fats, such as butter fat; and marine oils which can be converted into plastic or solid fats such as menhaden, pilcherd, sardine, whale and herring oils.

Preferred triglycerides include partially hydrogenated and unhydrogenated animal or vegetable oils which are liquid or semi-solid at room temperature, and the like.

It is known that those bisimidazoline compounds with shorter than C6 chain lengths do not soften well, while those longer than C22 become undesirably viscous when formulated. Preferably, fatty acids are substantially saturated, as unsaturated fatty acids tend to oxidize.

The next step in deriving the bisimidazolines involves cyclizing the polyamido amine. This reaction is accomplished by heating the polyamido amine at a temperature between about 125°C and 250°C under vacuum from 1 to 300 mm Hg. The extent of cyclization can be noted by analyzing tertiary amine content, generally referred to as the TAN value of the reaction mixture. The extent of. cyclization is an important factor, for remaining acylic amines can cause yellowing and malodor when applied to fabrics.

The most preferred bisimidazoline compound (1-ethylene bis [2-hydrogenated tallow imidazoline]) is commercially available from Sherex Co., Dublin, OH, in the form of free amine.

Component B

The organic acids, component B, used for ion pairing the bisimidazoline compound, component A, are selected from a variety of acids. The group of acids consists of carboxylic acids with a Cβ-22 alkyl or C7-C22 alkyl aryl chain, alkyl or alkyl aryl sulfonic acids having a Ci-22 alkyl chain, dicarboxylic acids having a C2-8 alkyl chain, and mixtures thereof. These include the following acids; hexanoic, heptanoic, octanoic, lauric, stearic, palmitic, oleic, behenic, elaidic, benzene sulfonic, methane sulfonic, ethane sulfonic, octane sulfonic, malic, oxalic, malonic, succinic, adipic, phthalic, etc. Ion pair complexes made of any of the above mentioned acids can be used to formulate a fabric softening composition of 5%-8% active component concentration when further reacted with component C, the Bronstedt acid. The preferred acids are Cδ-18 alkyl fatty acids, Cχ-3 alkyl sulfonic acids, and C -iβ alkyl aryl sulfonic acids. The ion pairs made with these acids can be formulated up to 18% concentration. Most preferred acids are Cβ-12 carboxylic acids and methanesulfonic acid. Ion pairs made of these acids can be formulated up to 23% concentration in the compositions herein. The ratio of the bisimidazoline compounds and organic acids is a key factor of the present invention. It is known that the ion pairing of bisimidazoline compounds with organic acids reduces the viscosity of the original bisimidazoline. It is a finding of the present invention that within a certain level of ion pairing of bisimidazoline with organic acids, an ion pair complex which has a viscosity low enough to be formulated into concentrations up to 23% and still retaining intrinsic softening performance benefits of the bisimidazoline over many known softening agents is obtained. This level is non-stoichiometric. The ion pair ratios are from about 1.0 : 1.8 to about 1.0 : 0.1 of bisimidazoline to organic acid for monoacids, and from about 1.0 : 0.9 to about 1.0 : 0.1 for diacids.

Component C The Bronstedt acid useful for completing the ion pairing are those having a pKa value of not greater than 6, provided that the pH of a dispersion of the acid is not greater than 5. These acids stabilize the electric charge of the ion pair structure obtained by the bisimidazoline compounds and organic acids, resulting in a unique non-stoichiometric ion pair complex. These Bronstedt acids also contribute in keeping the ion pair complex within a certain pH range, which is also critical for stabilization. Preferred Bronstedt acids are HC1, HBr, H2SO4, H3PO4, formic acid, acetic acid, methanesulfonic acid, and ethanesulfonic acid. Most preferred is HC1. The Ion Pair Complex The ion pair complex is prepared by combining the above mentioned components A, B, and C at a non-stoichiometric mole ratio, wherein A : B : C is from about 1.0 : 1.8 : 1.4 to about 1.0 : 0.1 : 2.0, when component B is a monoacid, and from about 1.0 : 0.9 : 1.4 to about 1.0 : 0.1 : 2.0 when component B is a diacid. The preferred ratio is about 1.0 : 0.5 : 2.0 for monoacids and 1.0 : 0.25 : 2.0 for diacids.

The ion pair complex is prepared by first melting component A, bisimidazoline, followed by addition of melted component B, organic acid, followed by the addition of the combined A and B components to an aqueous solution of component C, Bronstedt acid.

First, the bisimidazoline is heated to slightly above its melting point in a vessel equipped with a stirrer or other mixing device. The organic acid is added to the bisimidazoline as a liquid melt, slowly with stirring. In general, temperatures of from 80°C to 120°C are used for this stirring process. A nitrogen or other inert gas purge can be used to prevent hydrolysis and/or oxidation. Here, the bisimidazoline-organic acid mixture is formed.

When a cosoftener is used, it is preferably mixed with the melted bisimidazoline-organic acid mixture before adding them to the Bronstedt acid. The cosofteners are solid at room temperature and thus are easier to incorporate if they are melted and mixed after the bisimidazoline-organic acid mixture is formed.

The bisimidazoline-organic acid mixture or optionally the mixture of bisimidazoline-organic acid and cosoftener as obtained above is then added to the Bronstedt acid aqueous solution of component C. The Bronstedt acid is usually at a concentration of from about 0.3% to about 10% in water. The exact amount of water used and of the acid depends upon the particular ratio of ion pair complex to be formed, the pH of the ion pair complex and the final concentration of the softener composition.

The ion pair complex of the present invention is unique in that it is non-stoichiometric. The stoichiometric ratio of the bisimidazoline to organic acids is 1 : 2 since there are two secondary amines present in each molecule of the bisimidazoline. These amines are thought to react with the acids. When diacids are used for component B, one molecule of diacid is believed to react with two amine sites, and therefore included by half the ratio of monoacids.

The complexing of the amine and the anion c compounds results in an ion pair entity which is chemically distinct from either of the three starting materials.

This is confirmed by the melting point of the complex which is higher than either the bisimidazoline or organic acid when investigated with Differential Scanning Calorimetry. Without being bound by theory, components B and C are thought to pair with the two secondary amines, forming in part an ion pair of the following formula; (CH₂)2 (CH₂)2 / \ / \ Y- H-N N-H—-X"

I I

Rl Rl

HX: component B (in case it is a monoacid)

HY: component C The non-stoichiometric ion pairing would render a mixture of free, partially, and fully ion paired bisimidazolines, which as a whole is regarded as the ion pair complex in the present invention. The ion pair complex thus obtained is useful for treating textiles, especially fabric softening.

The ion pair complex is stable and flowable in a pH range of 2.5 - 4, preferably about 3.5. Another important factor for stabilizing and dispersing the ion pair complex is the particle size. The desired particle sizes can be achieved by use of in-line high shear mixing instruments such as the Tekmar Mill produced by the Ika-Works Co., Cincinnati, OH.

The ideal particle made from an ion pair complex is sufficiently small so as to be readily dispersed when formulated in an aqueous fabric softening composition. Preferably more than 80% of the ion pair complex has a particle size smaller than about 5 microns, more preferably smaller than about 1 micron. The ion pair complex can also be processed to larger particles and appl ied to a dispensing means for release to fabrics in the dryer operation.

The Composition The ion pair complex of the present invention shows excellent fabric softening performance, and can be formulated into a substantial¬ ly concentrated aqueous fabric softening composition. Compositions may include the ion pair complex particles as the only fabric softening agent, or combined with cosofteners. The active components of the composition are primarily fabric softening agents, but may also include ingredients such as those disclosed herein, and may include other ingredients not specifically listed herein. Preferred compositions contain cosofteners. In the present invention, cosofteners are added in order to enhance softening performance. The cosofteners are restricted to those which are solid at room temperature, for cosofteners of such nature are known to increase softening performance. Especially preferred are quaternary ammonium salts and fatty acid esters. The tallow substituted quaternary ammonium salts such as those known as MTTMAC (monotallow trimethyl ammonium chloride) and DTDMAC (ditallow dimethyl ammonium chloride) are well known in the art as fabric softener agents usually formulated in liquid compositions. Another type is the fatty acid esters of sorbitan or glycerol. Sorbitan monostearate is most pre¬ ferred among this type. This type is well known in the art as dryer- added fabric softening agents in sheet form. Among those mentioned above, DTDMAC is the most preferred. It is also known that by adding both the quaternary ammonium salts and fatty acid esters as cosofteners, a composition with preferable softening performance as well as fluidability is obtained. When either type of cosoftener is incorporated, the composition containing both the ion pair complex and cosoftener gives better softening performance than the ion pair complex or cosoftener alone. The cosoftener is usually comelted with the combined mixture of component A and B. This ensures that it is well dispersed. The examples illustrate the method of adding the cosoftener.

The ratio of the ion pair complex to the cosoftener is al so important to softening performance. The preferred ratio of the ion pair compound is wherein the ion pair complex is more than 25% by weight of the total active softening agents, preferably wherein the bisimidazoline in the ion pair complex to cosoftener is about 1.6 : 1 to about 2 : 1 by weight. A viscosity controll ing agent is usually present in the composi ¬ tion at a level not more than about 2.5%, especially when a concentrated formula is prepared. Viscosity controll ing agents can be organic or inorganic in nature. Examples of organic viscosity controll ing agents are fatty acids and esters such as fatty acid esters of sorbitan or glycerol , fatty alcohols, water-mi scible solvents such as short chain alcohols and ammonium salts such as TTMMAC (tritallow monomethyl ammonium chloride) obtained as Adogen 440 (Sherex Co. ) . Examples of inorganic viscosity control agents are water-soluble ionizable salts. A wide variety of ionizable salts can be used. Examples of suitable salts are the hal ides of the group IA and IIA metal s of the Periodic Table of the Elements, e.g. , CaCl2, gCl , NaCl , KBr, and LiCl . CaCl2 is preferred. 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. TTMMAC is preferred to be included when tallow substituted quaternary ammonium salts are contained as cosofteners in the composition at a substantially concentrated level . The amount of viscosity controlling agents used depends on the level of active ingredients used in the compositions and can be adjusted according to the desire of the formul ator. The viscosity controll ing agent is usually included in the formula in a flowable form either concurrently with or after the combined A and B components are added to an aqueous solution of component C.

The present compositions can contain sil icones to provide addi - tional benefits such as ease of ironing and improved fabric feel . The preferred silicones are polydimethylsiloxanes at a viscosity of from about 100 centistokes (cs) to about 100,000 cs, preferably from about 200 cs to about 60,000 cs. These silicones can be used as is, or they can be conveniently added to the softener compositions in a preemulsified form which is obtainable directly from the suppliers. Examples of these preemulsified silicones are 55% emulsion of polydimethylsiloxane (350cs) sold by Dow Corning Corporation under the trade name DOW CORNING 1157 Fluid and 50% emulsion of polydimethyl_: siloxane (10,000cs) sold by General Electric Company under the trade name General Electric R SM 2140 Silicones. The optional silicone component can be used in an amount of from about 0.1% to about 6% by weight of the composition.

Another type of silicone can be contained as antifoa ing agents. Examples of such is the 20% emulsion of DOW CORNING 1520 FLUID available from Dow Corning. This silicone can be used in an amount of from about 0.005% to about 0.05% of the composition.

Other minor ingredients include short chain alcohols such as ethanol and isopropanol which are often present in the commercially available quaternary ammonium compounds used as cosofteners. The short chain alcohols are normally present at less than about 3% by weight of the composition when quaternary ammonium compounds are selected as a cosoftener.

Additional ingredients can be added to the composition herein for their known purposes. Such ingredients include, but are not limited to, perfumes, emulsifiers, preservatives, antioxidants, bacteriocides, fungicides, colorants, dyes, fluorescent dyes, brighteners, opacifiers, freeze-thaw control agents, shrinkage control agents, and agents to provide ease of ironing. Such ingredients can be seen in the examples. These ingredients, if used, are added at their usual levels, generally each of up to about 2% by weight of the composition.

The aqueous fabric softening compositions of the present invention can be prepared by conventional methods. A convenient and satisfactory method is to prepare the softening active pre ix of the ion pair complex and cosoftener at about 100°C. The premix is injected into a heated aqueous solution of the Bronstedt acid, and mixed with agitation and high shearing, if the latter is necessary to achieve a certain particle size. Ingredients such as viscosity controlling agents can be added in the Bronstedt acid solution while mixing with the active premix, or can be added after the injection is completed. When TTMMAC is to be incorporated in the formula as a viscosity controlling agent, it is usually co elted with the softening active premix prior to mixing with the Bronstedt acid solution. Temperature-sensitive optional ingredients can be added after the fabric softening composition is cooled to a lower temperature. The aqueous fabric softening compositions of this invention are usually used by adding to the rinse cycle of conventional home laundry operations. Generally, rinse water has a temperature of from about 5° to about 30°C. The concentration of the fabric softener actives of this invention is generally from about 10 ppm to about 200 ppm, prefer- ably from about 25 ppm to about 100 ppm by weight of the aqueous rinsing bath.

In general, the present invention in its fabric softening method aspect comprises the steps of (1) washing fabrics in a conventional washing machine with a detergent composition; and (2) rinsing the fabrics in a bath which contains the above-described amounts of the fabric softeners; and (3) drying the fabrics. When multiple rinses are used, the fabric softening composition is preferably added to the final rinse. Fabric drying can take place either in an automatic dryer or in the open air.

Examples

The following examples illustrate the present inventions. The terminology used in the examples are defined below. The percentages, parts and ratios used herein are on a weight basis unless otherwise specified. Ingredients are described on the active ingredient basis as

"percent", and on the actual basis as "parts".

Definitions 1) Abbreviations used in Examples are defined below. a) Bisimidazoline:

1-ethylene bis(2-hydrogenated tallow i idazoline) b) HC1 solution:

31.5% aqueous solution c) CaU2 solution: 25% aqueous solution d) DTDMAC: a blend of di (hydrogenated) tallow dimethyl ammonium chloride, onotal low tri ethyl ammonium chloride, and ethanol in a nominal ratio of 76: 11 :13. e) Adogen 440: blend of tri tal low mono ethyl ammonium chloride (TTMMAC) and isppropanol at a nominal ratio of 80:20. f) Kathon:

1.5% active mixture of 5-chloro-2-methyl 4-isothiazol in -3-one and 2-methyl -4-isothiazol in-3-one. g) Tenox S-l: mixture of 20% /j-propyl -3,4,5-trihydroxybenzoate, 10% citric acid, and 70% propylene glycol . h) DC 1157 Fluid: 55% active emul sion of pol yd i methyl si loxane (350cs) . i ) DC 1520 Fluid:

20% active emul sion of polydi methyl si loxane. Tngredient (active) Parts Bisimidazoline 14.000 DTDMAC 8.434

Octanoic Acid 1.690 HCl solution 5.243 Adogen 440 2.062 1st CaCl2 solution 0.540 2nd CaCl2 solution 2.000 Kathon 0.033 Tenox S-l 0.025 DC 1157 Fluid 1.091 DC 1520 Fluid 0.040 Perfume 0.300

Deionized water

Balance

Example I contains as fabric softening active 7.0% of DTDMAC and the reaction product of 14.0% of bisimidazoline and 1.63% of octanoic acid and 1.65% of HCl. The mole ratio of bisimidazoline : octanoic acid : HCl is 1.0 : 0.5 : 2.0. It is prepared as follows: about 14.0 parts of molten bisimidazoline (melted under a dry nitrogen purge to prevent hydrolysis) is added to a heated premix vessel. To this, 1.69 parts of octanoic acid is added slowly and the mixture is stirred for 5 minutes. Then, 8.43 parts of molten DTDMAC and 2.1 parts of molten Adogen 440 are added to the above mixture and this premix is stirred and the temperature is maintained at 100°C. The premix is then added, with agitation, to a mix vessel containing deionized water, 5.24 parts of HCl solution, 1.09 parts of DC 1157 fluid and 0.040 parts of DC 1520 fluid which had been heated to 57°C. When the premix is 75-95% injected, 0.5 parts of CaCl2 solution is added for viscosity control. Another 2.0 parts of CaCl2 solution is added after premix addition is completed. At this point, additional CaCl2 solution and HCl solution can be added for viscosity and pH control, respectively if needed. This is followed by addition of 0.025 parts of Tenox S-l, 0.033 parts of Kathon, and perfume. Product is then cooled to room temperature.

Example II contains as fabric softening active 8.7% of sorbitan monostearate and the reaction product of 14.3% of bisimidazoline and 1.67% of octanoic acid and 1.69% of HCl. The mole ratio of bisimida¬ zoline : octanoic acid : HCl is 1.0: 0.5 : 2.0. It is prepared as follows : About 14.3 parts of molten bisimidazoline (melted under a dry nitrogen purge to prevent hydrolysis) is added to a heated premix vessel. To this, 1.67 parts of octanoic acid is added slowly and the mixture is stirred for 5 minutes. Then, 8.7 parts of molten sorbitan monostearate is added to the above mixture and this premix is stirred and the temperature is maintained at 100°C. The premix is then added, with agitation, to a mix vessel containing deionized water and 5.36 parts of HCl solution which had been heated to 57°C. When the premix is 75 - 95% injected, 1.5 parts of CaCl2 solution is added for vis¬ cosity control. Another 5.0 parts of CaU2 solution is added after premix addition is completed. At this point, additional CaU solution and HCl solution can be added for viscosity and pH control, respectively, if needed. This is followed by addition of 1.09 parts of DC 1157 fluid, 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and 0.005 parts of DC 1520 fluid. Tnqredient (active) Bisimidazoline 5 DTDMAC

Octanoic acid HCl

Kathon Tenox S-l 10 DC 1157 Fluid DC 1520 Fluid Perfume Deionized water

Example III contains as fabric softening active 2.5% of DTDMAC and 15 the reaction product of 5.0% of bisimidazoline and 0.58% of octanoic acid and 0.6% of HCl. The mole ratio of bisimidazoline : octanoic acid : HCl is 1.0: 0.5 : 2.0. It is prepared as follows : About 5.0 parts of molten bisimidazoline (melted under a dry nitrogen purge to prevent hydrolysis) is added to a heated premix vessel. To this, 0.58 parts of 20 octanoic acid is added slowly and the mixture is stirred for 5 minutes. Then, 3.0 parts of molten DTDMAC is added to the above mixture and this premix is stirred and the temperature is maintained at 100°C. The premix is then added, with agitation, to a mix vessel containing deionized water and 1.87 parts of HCl solution which had been heated to 2557°C. At this point, CaCl2 solution and HCl solution can be added for viscosity and pH control, respectively, if needed. This is followed by addition of 0.36 parts of DC 1157 fluid, 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and 0.005 parts of DC 1520 fluid. 0

5 Ingredient (active) Bisimidazoline

5 DTDMAC

Succinic Acid HCl

Kathon Tenox S-l

10 DC 1157 Fluid DC 1520 Fluid Perfume Deionized water

Example IV contains as fabric softening active 2.5% of DTDMAC and

15 the reaction product of 5.0% of bisimidazoline and 0.24% of succinic acid and 0.6% of HCl. The mole ratio of bisimidazoline : succinic acid : HCl is 1.0: 0.25 : 2.0. It is prepared as follows : About 5.0 parts of molten bisimidazoline (melted under a dry nitrogen purge to prevent hydrolysis) is added to a heated premix vessel. To this, 0.24 parts of

20 succinic acid is added slowly and the mixture is stirred for 5 minutes. Then, 3.0 parts of molten DTDMAC is added to the above mixture and this premix is stirred and the temperature is maintained at 100°C. The premix is then added, with agitation, to a mix vessel containing deionized water and 1.87 parts of HCl solution which had been heated to

25 57°C. At this point, CaCl2 solution and HCl solution can be added for viscosity and pH control, respectively, if needed. This is followed by addition of 0.36 parts of DC 1157 fluid, 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and 0.005 parts of DC 1520 fluid. 0

5

Example V contains as fabric softening active 7.5% of DTDMAC. It is prepared as follows: About 9.0 parts of molten DTDMAC is added to a heated premix vessel maintained at 100°C and stirred for 1 minute. The premix is then added with agitation, to a mix vessel containing deionized water and 0.032 parts of HCl solution which had been heated to 57°C. At this point, CaCl2 solution can be added for viscosity control, if needed. This is followed by addition of 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and 0.005 parts of DC 1520 fluid.

Ingredient (active) DTDMAC

HCl solution

Kathon

Tenox S-l DC 1520 Fluid

Perfume

Deionized Water

Example VI contains as fabric softening active 15.0% of DTDMAC. It is prepared as follows: About 18.1 parts of molten DTDMAC is added to a heated premix vessel maintained at 100°C and stirred for 1 minute. The premix is then added, with agitation, to a mix vessel containing

5 deionized water and 0.794 parts of HCl solution which had been heated to 57°C is added for pH control. At this point, CaU2 solution can be added for viscosity control, if needed. This is followed by addition of 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and

100.005 parts of DC 1520 fluid.

Parts 15.300 9.277 1.070 5.730 2.200 0.500 2.000 0.033 0.025 1.091 0.050 0.175

Balance

Example VII contains as fabric softening active 7.7% of DTDMAC and the reaction product of 15.3% of bisimidazoline and 1.07% of octanoic 0 acid and 1.81% of HCl. The mole ratio of bisimidazoline : octanoic acid : HCl is 1.0 : 0.3 : 2.0. It is prepared as follows: About 15.3 parts of molten bisimidazoline (melted under a dry nitrogen purge to prevent hydrolysis) is added to a heated premix vessel. To this, 1.07 parts of octanoic acid is added slowly and the mixture is stirred for 5 5 minutes. Then, 9.3 parts of molten DTDMAC and 2.2 parts of molten Adogen 440 are added to the above mixture and this premix is stirred and the temperature is maintained at 100°C. The premix is then added, with agitation, to a mix vessel containing deionized water and 5.73 parts of HCl solution which had been heated to 57°C. When the premix is 75-95% injected, 0.5 parts of CaCl2 solution is added for viscosity control. Another 2.0 parts of CaCl2 solution is added after premix addition is completed. At this point, additional CaU2 solution and HCl solution can be added for viscosity and pH control, respectively,, if needed. This is followed by addition of 1.09 parts of DC 1157 Fluid, 0.025 parts of Tenox S-l, and 0.033 parts of Kathon. The mixture is cooled to 43°C with continued agitation and addition of perfume and 0.005 parts of DC 1520 Fluid.

SOFTENING PERFORMANCE The above compositions of Examples I, II, III and IV were tested for softening performance using the following subjective evaluation methods. Examples I and II were compared versus Example VI, and Examples III and IV were compared versus Example V..

Test Conditions and Procedure

A total of 1.1 kg of fabric composed of 0.2 kg test fabrics (6-100% cotton terry face cloths) and 0.9 kg of ballast fabrics (8-U.S. cotton medium t-shirts) are placed in twin tub washers (National W102) at normal agitation setting with 25g of powder laundry detergent (Attack, Kao Co.). A total of 30 liters of 20°C water (3 grains/gallon hardness, Ca/Mg ratio 3/1) is added, followed by the test fabrics and ballast fabrics. The wash cycle is started and is allowed to proceed for 10 minutes, after which the fabric is transferred to the spinner compartment and spun for 2 minutes. The fabric is transferred back to the main washer compartment, and is rinsed for 10 minutes using an overflow rinse with a water flow rate of 9 liters/minute. The fabric is transferred again to the spinner compartment and spun for 2 minutes. Then, 30 liters of 3 grain/gallon water is added, the agitator is started, and the fabric softener is added. The fabrics from the spinner are placed in with the fabric softener, and are rinsed with agitation for 3 minutes.

The amount of fabric softener added depends on the concentration of the fabric softeners used. The in-rinse is 50 ppm of softener actives, i.e., bisimidazoline ion pair complex or bisimidazoline ion pair complex plus cosoftener, depending on the system being studied. The active agent of the ion pair complex here is calculated on the bisimidazoline basis. Thus, for systems where the total active softening agents are about 23% of the composition, 6 grams of fabric softener is used. In those systems where the total active softening agents are about 7.5% of the composition, 18 grams of fabric softener is used.

The fabrics are placed back in the spinner for two minutes. The terries are then removed from the spinner and line dried on a clothes rack overnight. They are graded blind the following day for softness by expert judges. The following scale is used:

0 PSU - No difference

1 PSU ■ I think there is a difference

2 PSU ■ I know there is a difference

3 PSU « There is a large difference 4 PSU ■ There is a very large difference

This is a relative scale and each PSU value is applicable only for the pair of treatments considered, and is not additive or used for comparison with other pair tests.

For each test, 2 individual washing machines are used, with 6 terry face cloths placed in each washer, and 3 judges grade the softening performance, blind. The order of grading is randomized to eliminate order bias.

Table VIII shows the results for the softening performance of compositions prepared in Examples I and II compared to Example VI, and Examples III and IV compared to Example V. To verify the advantage of the present invention over the standard softener active, DTDMAC (which is adequately formulated into a practical composition in Examples V and VI), a procedure of 2 to 4 cycles of wash, rinse, soften, dry and grade were used. In this table, a positive PSU value indicates that the given composition softened better than the standard DTDMAC control compositions, Examples V and VI, which for simplicity is normalized to 0.0 PSU. As can be seen in Table VIII, compositions prepared in Examples I, II, III and IV of the present invention show superior softening activity and are statistically significant at the 95% confidence level for each cycle tested, compared with Example V or VI, as indicated.

Claims

WHAT IS CLAIMED IS:

1. An ion pair complex comprising;

A. A bisimidazoline of the formula;

(CH₂)2 (CH₂)2

/ \ / \

N N-(CH2)n-N N

\\ / \ // C C

I I

Rl Rl wherein n is 2 - 4 and Rl is independently selected from Cβ- 2 saturated and unsaturated alkyl groups;

B. organic acids selected from the group consisting of carboxylic acids having a Cβ-22 alkyl or C7-22 alkyl aryl chain, alkyl or alkyl aryl sulfonic acids having a Ci-22 alkyl chain, dicarboxylic acids having a C2-8 alkyl chain, and mixtures thereof;

and wherein the mole ratio of components A : B : C is from 1.0 : 1.8 : 1.4 to 1.0 : 0.1 : 2.0 when component B is a monoacid, and from 1.0 : 0.9 : 1.4 to 1.0 : 0.1 : 2.0 when component B is a diacid.

2. An ion pair complex according to Claim 1 wherein the pH of an aqueous dispersion of the complex is 2.5 - 4, preferably wherein said Bronstedt acid is selected from the group consisting of HCl, HBr, H2SO4, H3PO4, formic acid, acetic acid, methanesulfonic acid, and ethanesulfonic acid.

3. An ion pair complex according to Claim 1 or 2 wherein n is 2 and wherein Rl is selected from saturated or unsaturated alkyl chains of Ci6 or i8, preferably wherein Rl is hardened tallow.

4. An ion pair complex according to Claims 1, 2 or 3 wherein component B is selected from C6-18 alkyl fatty acids, C1-C3 alkyl sulfonic acids, and Cχ_i8 alkyl aryl sulfonic acids, preferably wherein component B is selected from fatty acids with a chain length .

5. An aqueous fabric softening composition comprising from 5% to 18% by weight of bisimidazoline as an ion pair complex according to claims 1, 2, 3 or 4, preferably wherein more than 80% of the ion pair complex has a particle size smaller than 5 microns.

6. An aqueous fabric softening composition according to Claim 5 wherein CaCl2 is included as a viscosity controlling agent.

7. An aqueous fabric softening composition according to Claims 5 or 6 containing cosofteners which are solid at room temperature, and wherein the total of active softening agents are from 5% to 18% by weight, preferably wherein the cosoftener is selected from the group consisting of a fatty acid ester of sorbitan or glycerol and an acyclic quaternary ammonium salt having the formula;

R2

I

R4 - N+ - R³ A-

I

R3 wherein R is an acyclic aliphatic C15-22 hydrocarbon group, R³ is a C1-4 saturated alkyl or hydroalkyl group, R⁴ is selected from R and R³, and A is an anion.

8. An aqueous fabric softening composition according to Claims 5, 6 or 7 wherein the bisimidazoline in the ion pair complex is more than 25% by weight of the total active softening agents, preferably wherein the ratio of the bisimidazoline in the ion pair complex to the cosoftener is from 1.6 : 1 to 2 : 1 by weight.

9. An aqueous fabric softening composition according to Claims 5, 6, 7 or 8 wherein an ammonium salt viscosity controlling agent of the following formula is included;

R6

I

R6 - N+ - R6 A-

I

R7 wherein R⁶ is an acylic aliphatic C15-C22 hydrocarbon group, R? is a C1-C4 saturated alkyl or hydroalkyl group, and A is an anion, and which additionally contains a fatty acid ester of sorbitan or glycerol .

10. An aqueous fabric softening composition comprising from 5% to 23% by weight of bisimidazoline as an ion pair complex comprising;

A. A bisimidazoline of the formula;

(CH₂)2 (CH₂)2

/ \ / \

N N - (CH2)2 - N N

\\ / \ // c c

I I

Rl Rl wherein Rl is selected from alkyl chains of Cβ-22 5

B. organic acids selected from the group consisting of Cβ to C12 alkyl fatty acids; C. Bronstedt acids selected from the group consisting of HCl, HBr, H2SO4, H3PO4, formic acid, acetic acid, methanesulfonic acid, and ethanesulfonic acid;

and wherein the mole ratio of components A:B:C is from 1.0 : 1.8 : 1.4 to 1.0 : 0.3 : 2.0, preferably wherein more than 80% of the ion pair complex has a particle size smaller than 5 microns.

11. An aqueous fabric softening composition according to Claim 10 wherein CaCl2 is included as a viscosity controlling agent and preferably containing cosofteners which are solid at room temperature, and wherein the total of active softening agents are from 5% to 23% by weight, preferably wherein the bisimidazoline in the ion pair complex is more than 25% by weight of the total active softening agents.

12. An aqueous fabric softening composition according to Claim 11 wherein the cosoftener is an acyclic quaternary ammonium salt having the formula;

R2

I

R4 - N+ - R³ A-

I

R³ wherein R2 is an acyclic aliphatic Ci5_22 hydrocarbon group, R³ is a C1-4 saturated alkyl or hydroalkyl group, R* is selected from R2 and R³, and A is an anion; or a fatty acid ester of sorbitan or glycerol; preferably wherein an ammonium salt viscosity controlling agent of the following formula is included;

R6

I

R6 - N+ - R6 A-

I

R⁷ wherein Rδ is an acylic aliphatic C15-C22 hydrocarbon group, R⁷ is a C1-C4 saturated alkyl or hydroalkyl group, and A is an anion.

12. A process for preparing an ion pair complex according to Claims 1, 2, 3 or 4 by first melting component A, followed by the addition of melted component B, followed by the addition of the mixture of component A and B into an aqueous solution of component C.

13. A process for preparing an aqueous fabric softening composition according to Claims 5, 6, 7, 8, 9, 10 or 11 by first melting component A, followed by the addition of melted component B, followed by the addition of melted cosoftener, followed by the addition of the mixture of components A, B, and cosoftener into an aqueous solution of component C.