GB2123043A - Fabric softening composition - Google Patents

Abstract

An improved fabric softening composition is provided by the synergistic combination of a cationic softening agent and a higher alkyl sulphonate. The preferred cationic compounds are the water-soluble or dispersible (a) di-longchain alkyl-di- shortchain alkyl quaternary ammonium salts and (b) 2-longchain alkyl imidazolinium salts. The preferred alkyl (i.e. paraffin) sulphonates are the C14 to C22 paraffin sulphonates. The preferred ratio of cationic compound to paraffin sulphonate ranges from 5:1 to 12:1 on a weight basis. The preferred form of the composition is as an aqueous dispersion containing from 2 to 5% by weight of cationic compound and 0.2 to 1% paraffin sulphonate. A process for making the compositions of the invention is also provided along with a process of treating laundry materials in the rinse cycle of the laundering operation.

Description

SPECIFICATION Fabric softening composition The present invention relates to improved, highly efficacious, fabric softening compositions utilizing a combination of cationic fabric softening compound or mixture of such compounds and a higher alkyl sulphonate which by itself does not provide any softening effect to the laundry materials, and processes for making and using such compositions. The unique and synergistic effect of the combination of cationic and paraffin sulphonate permits the formulation of softening compositions of lower active ingredient levels (A.l.) than when using straight cationic material to obtain comparable softening effect. This permits wider latitude in preparing the compositions as well as significant monetary savings.

Empirically it has been determined that for a normal wash load (e.g. 8 to 10 Ibs) in the usual washing machine utilizing about 35 litres of water, about 30 to 60 grams of a 6% active cationic conditioner results in very acceptable softening. On a scale of 1 to 10 of softness rating, this means a rating of about 9 to 1 0.

At 6 and above there is to the consumer a perceptible difference between values of 6, 7, 8, 9 and 10.

From 1 to 5, the wash is totally unsatisfactory being very harsh and "boardy" in feel. At these levels the consumer generally cannot perceive any differences. Of course, the expert, with more experience and sophistication can discern differences between all these numerical ratings.

The 6% active cationic level has been the general industry-wide standard since higher concentrations in aqueous systems are often difficult to formulate, the stability may be poor, pourability deficient, gel-formation a serious problem, and dispersibility in the laundry water difficult leading to poor softening and/or staining.

In U.S. Patent 4,000,077 there are described improved fabric softening compositions combining a cationic softener with a long chain aliphatic alcohol sulphate (including ethoxylated alcohol sulphates). It is clear in this patent and it has been empirically established that lower levels of total actives (i.e. below 6%) can give softening equivalent to 6% cationic alone.

In U.S. Patent 3,997,453 fabric softening compositions of improved cold water dispersibility are obtained by the conjoint use of minor amounts of specified anionic sulphonates. Ratios of cationic to anionic of from 80:1 to 3:1, 50:1 to 4:1 and 40:1 to 5:1 are disclosed. Among the disclosed sulphonates are the C8 to C20 paraffin sulphonates.

The present invention aims to provide a fabric softening composition of excellent performance and which is economical as well.

This invention also aims to provide cationic fabric softeners utilizing lower levels of active ingredient but which give softening levels comparable to compositions of cationic alone at higher levels of active ingredients.

In accordance with the present invention, a fabric softening composition is provided which comprises an aqueous dispersion of a cationic fabric softener and a long-chain paraffin sulphonate in a weight ratio of from 5:1 to 12:1 (softener:sulphonate).

The cationic softeners useful herein include the conventional quaternary ammonium fabric softeners and particularly the water dispersible di-longchain, di-shortchain quaternary ammonium salts and the 2-long-chain imidazolinium salts. Of particular preference are the di-C,2 to C30 alkyl, di-C1 to C3 alkyl quaternary ammonium salts (e.g. chloride, sulphate, methosulphate, and acetate) and the 2-C,3 to C30 alkyl, 1 ,1-disubstituted imidazolinium salts (e.g. chloride, sulphate, methosulphate or acetate).

Generally the foregoing compounds may be represented by the following formulae for the imidazolinium softeners (A and AA) and quaternary salts (B):

Formula (A) Wherein: R' represents a C8 to C30 aliphatic radical and preferably a C14 to C,8 alkyl or alkenyl group; R2 and R3 independently represent any of R1 or preferably, a lower alkyl or substituted alkyl group of C1 to C4 such as haloalkyl, hydroxyalkyl or acylaminoalkyl; X represents a water-solubilizing anion such as a chloride, bromide, iodide, fluoride, sulphate, methosulphate, nitrite, nitrate, phosphate, or carboxylate, (e.g. acetate, adipate, phthalate, benzoate or oleate) group.

The preferred compounds have the formula:

Formula (AA) Wherein: R' is as defined for Formula (A): R2 may represent any of R' or preferably a lower alkyl group or a substituted alkyl group of C, to C4 such as haloalkyl or hydroxyalkyl; R4 may represent a hydrogen atom or a C1 to C4 alkyl group or substituted alkyl group; R5 may represent any of R' and R2, preferably a C8 to C30 aliphatic group and more preferably a C14 to C18 alkyl or alkenyl group; and X is as defined for Formula (A).

The quaternary ammonium compound has the general formula:

Formula (B) wherein the R groups which may be the same or different each represent a C1 to C30 aliphatic group, preferably an alkyl group or an alkenyl or an aryl group (e.g. a phenyl, tolyl, or cumyl group), or an aralkyl group (e.g. a benzyl, or a phenethyl group); halo, amido, hydroxy, or carboxy substituted alkyl, alkenyl, aryl or aralkyl group thereof; with the proviso that at least two of the R groups represent a C14 to C30 aliphatic group and preferably a C14 to C22 group and the other R groups represent a lower alkyl and more preferably at least two R groups represent a C14 to C18 aliphatic group and the other R groups represent a lower alkyl of C1 to C4 carbon atoms (and most preferably represent methyl or ethyl groups) and Y represents an anion as defined for X for Formula (A).

Typical imidazolinium softeners include the following within the above formula (A): 2-heptadecyl-1 methyl1 -oleylamidoethyl imidazolinium ethosulphate; 2-heptadecyl- -methyl-l -(2-stearoylamido)ethylimidazolinium sulphate; 2-heptadecyl- 1-methyl-I -(2-stearoylamido)ethylimidazolinium chloride; 2-coco-l -(2-hydroxyethyl)- 1 -benzyl imidazolinium chloride; 2-coco-l -(hydroxyethyl)- 1 -(4-chlorobutyl)-imidazolinium chloride; 2-coco-1 -(2-hydroxyethyl)- 1 -octadecenyl-imidazolinium chloride; 2-tall oil fatty-i -(2-hydroxyethyl)-i -benzyl imidazolinium chloride;; 2-tall oil fatty-l -(2-hydroxyethyl)-l -(4-chlorobutyl)-imidazolinium chloride; 2-heptadecenyl-1-(2-hydroxyethyl)-1-(4-chlorobutyl)-imidazolinium chloride; 2-heptadecenyl-i -(2-hydroxyethyl)-i -benzyl imidazolinium chloride; and 2-heptadecyl-1-(hydroxyethyl)-1-octadecyl imidazolinium ethyl sulphate.

Typical cationic compounds of Formula (B) include the following: distearyl dimethyl ammonium chloride; ditallow dimethyl ammonium chloride; dihexadecyl di methyl ammonium chloride; distearyl di methyl ammonium bromide; di(hydrogenated tallow) dimethyl ammonium bromide; distearyl, di(isopropyl) ammonium chloride; and distearyl dimethyl ammonium methosulphate.

In addition to the cationic softening component of the present invention, there may be also included in the aqueous compositions numerous conventional, supplemental materials or optional components which do not adversely affect the stability and/or functional characteristics of the present invention. Thus, for example, there may be present minor amounts of various surfactant materials and in particular certain surfactant phosphate esters which may be desirable to effect anti-static control of the laundered goods. Such conventional additional components also include perfumes, dyes, pigments, germicides, optical brighteners and anti-corrosion agents (e.g. sodium silicate). Where used, each of these may comprise for example up to 1% by weight of the compositions of the present invention.

It may also be desirable to supplement and/or modify the viscosity features of the composition of the present invention by the addition of electrolyte material such as calcium chloride, sodium nitrate or sodium formate e.g. in amounts from about 0.05 to about 5% by weight. Minor proportions of other components may also be included such as the lower alkanols, e.g. ethyl and isopropyl alcohol as well as the conventional opacifiers particularly of the resin emulsion types so well known in the art.

It is of course understood that most commercial materials contain a mixture of moieties. Thus the long chain substituents on the cationics may not only be a single carbon length chain but more probably a mixture. In this regard a particularly useful quaternary salt wherein the alkyl substituents are derived from tallow may contain a mixture about 35% C16 and 60% C18 and minor amounts of Ca4.

Similarly the paraffin sulphonate may be a singie chain length product but, again, more generally a mixture, and preferably such a mixture could be a mixed C14 to C17 (e.g. 26% C14; 32% C15; 25% C16; 14% C17; 4% C13; 1.5% C18 and 0.5% C12). Other mixed alkyls can of course be used but the preferred ones contain at least about 90% in the C14 to C17 range.

In general, the aqueous compositions of this invention contain from 2% to 5% of the cationic compound and from 0.2% to 1% of the paraffin sulphonate with the ratio of cationic to sulphonate ranging from 5:1 to 12:1. The preferred compositions have a total content of active ingredients (i.e.

cationic plus sulphonate) of from about 4% to about 6% with from 4% to 5.5% most preferred and a most preferred ratio of cationic to sulphonate of about 10:1.

The preferred general process for making the compositions of the present invention depends upon whether a batch or continuous technique is used. In a batch process about 2/3 of the formula amount of water is heated to about 35-500C. Separately the cationic and paraffin sulphonate are combined to form a fluid mixture (generally heating to 50-550C). The latter is then added to the preheated water and mixed until a homogeneous mass is obtained. Thereafter the remaining water is added with mixing.

In a continuous process the premix of cationic compound and paraffin sulphonate (at 50--550C) is added to the total formula amount of water which has been heated to about 700C.

The invention may be put into practice in various ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples. Parts, where given, are by weight, unless otherwise indicated.

Examples 1A to 1D (A) A 40x40 cm cotton towel prewashed six times to remove all material which might have been in the towel was rinsed in tap water at room temperature and after air-drying was cut into 5 pieces.

Each piece was treated with 1.5 grams of an aqueous composition containing 4% distearyl dimethyl ammonium chloride (DSDMAC). The softened towel pieces were evaluated through a paired comparison method against the following compositions used also to treat towels as above.

(B). 1.5 grams aqueous softener containing 3.75% DSDMAC and 0.14% C14-17 sodium paraffin sulphonate (SAS).

(C). 1.5 grams aqueous softener containing 3.50% DSDMAC and 0.28% SAS.

(D). 1.5 grams aqueous softener containing 3.25% DSDMAC and 0.43% SAS.

The results of the evaluation indicated that (C) was the best with (D) next, followed by (A) and then (B). It should be noted that (C) and (D) contain significantly less cationic and even less total actives than (A) (cationic alone) and yet give better softening. In the case of (B) the amount of SAS was too low to give the synergistic effects shown by (C) and (D) which are examples of the present invention.

Examples 2 to 5 Further examples of aqueous compositions of this invention were made up as follows: % DSDMAC % SAS Ex. 2 3.67 0.52 3 4.40 0.425 4 4.40 0.90 5 4.00 0.33 The DSDMAC of the foregoing examples had a molecular weight of about 575 and includes in addition to C,8 alkyl some C,6 alkyl as well.

The paraffin sulphonate had a molecular weight of about 328 according to the Epton method of titration of the anionic surfactant with a cationic surfactant of known molecular weight using methylene blue as indicator.

Examples 6A to 6H Each of the foregoing examples 1 B, 1 C, 1 D, 2, 3 4 and 5 was repeated utilizing the following cationic compounds and paraffin sulphonates with comparable results: A. di-octadecyl, diethyl ammonium methosulphate.

B. di-hexadecyl di-isopropyl ammonium acetate.

C. di-eicosyl dimethyl ammonium bromide.

D. 2-heptadecyl- -methyl-l -oleylamidoethyl imidazolinium ethosulphate.

E. 2-coco-i -(2-hydroxyethyl)- 1 -benzyl imidazolinium chloride.

F. distearyl, hydroxypropyl methyl ammonium chloride.

G. C18 paraffin sulphonate.

H. C18 paraffin sulphonate.

The aqueous softening compositions of this invention are generally applicable as other such compositions, particularly useful in the rinse cycle of an automatic laundry machine. In such operations as well as in any other desired method of treating clothes, the compositions are usually employed to provide generally an actives concentration of from about 0.005% to 0.3% based on the weight of clothes treated preferably 0.007% to about 0.2% and most preferably from about 0.01% to about 0.15%.

Claims (9)

Claims

1. An aqueous fabric softening composition comprising from 2% to 5% of a cationic softener and from 0.2% to 1% of a C14 to C22 paraffin sulphonate in a weight ratio of about 5:1 to 12:1.

2. A composition as claimed in Claim 1 in which the cationic compound is a water dispersible dilong chain aliphatic, di-short chain aliphatic quaternary ammonium salt or a 2-long chain-il -di- substituted imidazolinium salt or a mixture thereof.

3. A composition as claimed in Claim 2 in which the cationic compound is distearyl dimethyl ammonium chloride.

4. A composition as claimed in Claim 1, 2 or 3 in which the paraffin sulphonate is a C14-C17 paraffin sulphonate.

5. A composition as claimed in any one of Claims 1 to 4 in which the weight ratio of cationic compound to sulphonate is about 10:1.

6. A composition as claimed in Claim 1 substantially as specifically described herein with reference to any one of Examples 1 C, 1 D, 2 to 5 and 6A to 6H.

7. A process for preparing a composition as claimed in any one of Claims 1 to 6 which comprises adding a liquid premix of the cationic compound and paraffin sulphonate at a temperature of about 40 to 700C to a major amount of the formula weight of water which has been preheated to a temperature of from about 350C to about 750C and mixing to obtain an homogeneous dispersion of the active ingredients in the water.

8. A process as claimed in Claim 7 substantiaily as specifically described herein.

9. A composition as claimed in any one of Claims 1 to 6 whenever made by a process as claimed in Claim 7 or Claim 8.

1 0. A process for treating clothes to soften them which comprises adding to the clothes in water sufficient of a composition as claimed in any one of Claims 1 to 6 or Claim 9 to provide a concentration of about 0.005 to about 0.3% thereof based on the weight of clothes.