DE69028667T2 - Laundry softener - Google Patents

Description

The present invention relates to a fabric softener and a process for its preparation. In particular, the present invention relates to a fabric softener for use in the rinse stage of a fabric washing process.

In US Patent 4 137 180 (Lever Brothers Company) cationic diesters of the following formula

wherein each of R¹, R² and R³ is an alkyl or hydroxyalkyl group having 1 to 4 carbon atoms or a benzyl group, each of R and R are alkyl chains having 11 to 23 carbon atoms and X⊃min; is a water-soluble anion.

It was proposed in EP Patent Specification 239 910 (P&G) to formulate fabric conditioning compositions containing ester-linked quaternary ammonium materials of the following formula:

wherein each R¹ group is independently selected from C₁₋₄alkyl, alkenyl or -hydroxyalkyl groups; each R² group is independently selected from C alkyl or alkenyl groups;

T is

and n is an integer with a value from 0 to 5.

These ester-linked quaternary ammonium materials are particularly preferred for use in fabric conditioning agents because they are more biodegradable than conventional quaternary ammonium materials.

In the past, difficulties have been encountered in preparing fabric softeners containing exclusively the above-mentioned softening material at levels above 0.1% by weight by the known process of premelting the material followed by dispersing the melt in hot water with stirring, because after melting a highly viscous phase was formed which was very difficult to disperse. The products obtained from such a process were not of satisfactory stability and tended to thicken to an unacceptably high viscosity on storage. Attempts to prepare fabric softeners by cold dispersion resulted in inhomogeneous products of unacceptably high viscosity.

It is an object of the present invention to provide fabric softeners containing the above-mentioned biodegradable quaternary ammonium compounds. It is a second object of the invention to provide biodegradable fabric softeners which are of acceptable stability. Further objects of the invention are to provide fabric softeners which can be easily prepared and which provide adequate softening of the fabrics treated therewith.

Surprisingly, it has been found that one or more of the above-mentioned problems can be overcome and/or one or more of the above-mentioned objectives can be achieved when the specific ester-linked quaternary ammonium materials as mentioned above are used in combination with one or more specific extender materials are used.

Accordingly, the present invention relates to a laundry softener comprising:

(i) from 3 to 30 weight percent of an ester-linked quaternary ammonium material of the formula:

wherein each group is independently selected from C1-4 alkyl, alkenyl or hydroxyalkyl groups; each R2 group is independently selected from C8-28 alkyl or alkenyl groups;

T is

and n is an integer with a value from 0 to 5; and

(ii) at least 0.5% by weight of an extender material, which is a mixture of

(a) an ester-linked mono-long alkyl or alkenyl quaternary ammonium compound containing a single long C8-28 alkyl or alkenyl group linked to the quaternary ammonium molecule via an ester linkage; and one or more compounds of:

(b) a tertiary amine containing one C8-28 alkyl or alkenyl group and two C1-4 alkyl, alkenyl or hydroxyalkyl groups;

(c) a predominantly linear non-ionic ester material;

(d) a predominantly linear C8-28 fatty alcohol material, a C8-28 fatty acid material or a salt thereof, or;

(e) an ester of a predominantly linear C8-18 fatty acid with a polyhydric alcohol;

wherein the composition has a pH of less than 8.0 and is prepared by heating a mixture containing the materials (i) and (ii) to a temperature above 40ºC, followed by dispersing the mixture in water.

The compositions of the invention may take a variety of forms, such as pastes, liquids, etc., and may be impregnated onto substrates, for example for use in tumble dryers. Preferably, the compositions of the invention are liquids containing an aqueous base in which the active ingredients are dispersed.

Suitable ester-linked quaternary ammonium materials (i) and their preparation processes are described, for example, in US Patent 4,137,180 (Lever Brothers). A preferred material is 1,2-ditalgoxy-3-trimethylammonium propane chloride.

Preferably, the compositions have a high active content, e.g. comprising more than 8% of the ester-bound quaternary ammonium compounds.

The diluent material (ii) may be selected from mono-long alkyl or alkenyl tertiary or quaternary ammonium compounds and predominantly linear nonionic materials, or mixtures thereof. In this specification, the term predominantly linear nonionic material refers to materials having a molecular backbone to which no or only a small number of side groups are attached. Preferably, the molecular backbone accounts for more than 75% by weight of the molecule, more preferably more than 90%. In selecting diluent materials for use in a composition of the invention, it is preferred to use only those materials which are of acceptable biodegradability.

Particularly useful extender materials are:

(A) Tertiary amines containing one C8-28 alkyl or alkenyl group and two C1-4 alkyl, alkenyl or hydroxyalkyl groups. These materials are preferably used in protonated form.

(B) Ester-linked mono-long alkyl or alkenyl quaternary Ammonium compounds containing a C₈₋₂₈ alkyl or alkenyl group linked to the quaternary ammonium molecule via an ester bond. Preferred materials within this class are materials of the formula:

wherein R¹, R², T and n have the same meaning as in formula I and R³ is a hydrogen or a hydroxy group. Of these materials, those in which R³ is a hydroxy group are preferred. These materials show surprisingly good plasticizing performance.

(C) Predominantly linear nonionic ester materials, for example esters of C8-28 fatty acids and C1-30 monohydric alcohols. Particularly preferred is the use of ethyl stearate, lanolin and jojoba oil.

(D) Predominantly linear C8-28 fatty alcohol materials, C8-28 fatty acid materials or their salts. Of these materials, the use of free monocarboxylic fatty acid materials is particularly preferred.

(E) Esters of predominantly linear C8-28 fatty acids with polyhydric alcohols. Preferred esters are glycerol monostearate, sorbitan monostearate and the monoesters of polyethylene glycol with a molecular weight between 200 and 2000.

Preferably, the content of extender material is more than 0.2%, particularly preferred are systems containing more than 0.5% extender material. The content of extender material is usually 50% by weight of the composition preferably less than 30%, typically from 0.5 to 10% by weight of the composition.

The weight ratio of ester-linked quaternary ammonium materials (i) to extender materials (ii) is preferably from 20:1 to 1:10, more preferably from 10:1 to 1:2, most preferably from 9:1 to 1:1.

The compositions of the invention are obtainable by heating a mixture of materials (i) and (ii) to a temperature above 40°C, followed by dispersing the mixture in water. Preferably, the materials are heated to a temperature above 50°C and dispersed in water of elevated temperature. Compositions prepared by this process show surprisingly good stability and no, or only a small, increase in viscosity on storage. It is believed that this increased stability is caused by the particularly good homogeneity of the products obtained using this process. Therefore, particularly preferred products according to the present invention contain the above-mentioned two materials (i) and (ii) dispersed in water, wherein the mean particle diameter of the dispersed plasticizer phase is less than 10 µm, preferably less than 7 µm, most preferably less than 3 µm. Such dispersions of small particles are often referred to as microdispersions.

The compositions of the invention may preferably have a pH of more than 2.0. Preferably, the pH of the composition is less than 8.0, more preferably less than 5.0. Particularly preferred are pH values in the range from 2.5 to 4.0.

The compositions of the invention may contain, in addition to the two ingredients described above, other active ingredients, such as additional fabric conditioning materials.

When selecting the optional ingredients, it is preferred to use materials that do not significantly affect the biodegradability of the composition. It is therefore preferable to reduce the content of non-biodegradable or less biodegradable materials to a minimum.

Preferably, the compositions of the invention do not contain large amounts of conventional non-ester-bound quaternary ammonium compounds, preferably the compositions of the invention are substantially free of these quaternary ammonium compounds.

Plasticizing materials which can be incorporated in a composition according to the invention are amines, such as those described in EP 89200113.2, or biodegradable amphoteric plasticizing materials, such as those described in EP 89200113.2.

Preferably, the amount of active materials other than the above-mentioned ester-linked materials and extender materials is relatively low, i.e. the weight ratio of other plasticizer materials to the total amount of the two essential plasticizer components is preferably lower than 2:1, more preferably lower than 1:1, most preferably lower than 0.5:1.

The composition may also contain one or more optional ingredients selected from non-aqueous solvents such as C₁₋₄ alkanols and polyhydric alcohols, pH buffering agents such as strong or weak acid e.g. HCl, H₂SO₄, phosphoric, benzoic or citric acid, rewetting agents, viscosity modifiers such as electrolytes e.g. calcium chloride, anti-gelling agents, perfumes, perfume carriers, fluorescers, dyes, hydrotropes, anti-foaming agents, soil carriers, enzymes, optical brighteners, opacifiers, stabilizers such as guar gum and polyethylene glycol, emulsifiers, anti-shrinking agents, anti-creasing agents, fabric curling agents, anti-staining agents, soil release agents, germicides, linear or branched silicones, fungicides, antioxidants, anti-corrosive agents, preservatives such as Bronopol (Trade Mark), a commercially available form of 2-bromo-2-nitropropane-1,3-diol, Dyes, bleaches and bleach precursors, wrinkling agents, antistatic agents and ironing aids.

These optional ingredients, if added, are preferably present at levels of up to 5% by weight of the composition.

A preferred method of preparing the compositions according to the invention is to form a molten mixture of the ester-linked quaternary ammonium materials (i) and the extender materials (ii), possibly in combination with other emollient materials and/or optional ingredients, and to introduce this premix into water with stirring to form a dispersion and then to add any other optional ingredients.

In use, the fabric conditioning composition of the invention can be added to a large volume of water to form a solution with which the fabrics to be treated are contacted. Usually, the total concentration of the ester-linked quaternary ammonium compounds (i) and the extender compound in this solution will be between about 30 ppm and 1000 ppm. The weight ratio of the fabrics to the solution will usually be between 1:1 and 1:20.

The invention will now be explained in more detail by the following examples.

example 1

The following compositions were prepared by heating the active ingredients to a temperature of 60°C and dispersing the premelt in water at 60°C with stirring. The compositions obtained according to the invention were homogeneous dispersions in which the average diameter of the dispersed active particles was less than 1 µm was.

1) 1,2-Ditalgoxytrimethylammoniumpropane chloride

2) 1-Tallowoxy-2-hydroxytrimethylammoniumpropane chloride

3) Isopropyl alcohol

4) Stearyl esters of choline

5) Commercially available biodegradable plasticizer, 90% active, 10% IPA

2 g of formulations A to D were added to 1 liter of ambient temperature tap water containing 0.001% by weight of sodium alkylbenzene sulfonate to simulate the transfer of anionic detergent active compound from laundry. 800 ml of the resulting solution was placed in a tergotometer vessel and four pieces of terry cloth fabric (40 g total weight) were added. The fabrics were treated for 5 minutes at 60 rpm and spun and line dried. The dried fabrics were evaluated for softness by a panel of experts using a round robin test protocol.

The order of preference for the above-mentioned compositions was:

B > C > A > D

These results show a surprisingly good softening effect for the composition of the present invention (A to C) compared to the commonly available biodegradable active softeners (D).

Example 2

The following compositions were prepared as in Example 1.

Example 3

The following compositions were prepared as in Example 1.

Footnotes to the above table

1) 1-Tallowamidoethyl-2-tallowimidazoline (protonated)

2) Industrial alcohol denatured with methanol

3) Methyl-di-hydrogenated tallow amine (protonated)

Example 4

The following compositions were prepared as in Example 1.

1) Dimethyl-hydrogenated tallow amine (protonated)

Example 5

The following compositions were prepared as in Example 1.

1) Hydrogenated tallow fatty acid

2) C₁₄₋₁₅-alcohol ethoxylate with 11 moles of ethylene oxide

Claims (5)

1. A laundry softener containing: (i) from 3 to 30 weight percent of an ester-linked quaternary ammonium material of the formula: wherein each R¹ group is independently selected from C₁₋₄ alkyl, alkenyl or hydroxyalkyl groups; each group is independently selected from C₂₋₂₈ alkyl or alkenyl groups; T is and n is an integer with a value from 0 to 5; and (ii) at least 0.5% by weight of an extender material, which is a mixture of (a) an ester-linked mono-long alkyl or alkenyl quaternary ammonium compound containing a single long C2-C28 alkyl or alkenyl group linked to the quaternary ammonium molecule via an ester linkage; and one or more compounds of: (b) a tertiary amine containing one C8-28 alkyl or alkenyl group and two C1-4 alkyl, alkenyl or hydroxyalkyl groups; (c) a predominantly linear non-ionic ester material; (d) a predominantly linear C8-28 fatty alcohol material, a C8-28 fatty acid material or a salt thereof, or; (e) an ester of a predominantly linear C8-18 fatty acid with a polyhydric alcohol; wherein the composition has a pH of less than 8.0 and is prepared by heating a mixture containing the materials (i) and (ii) to a temperature above 40ºC, followed by dispersing the mixture in water. 2. A fabric softener containing a dispersion in water consisting of: (i) from 3 to 30 weight percent of an ester-linked quaternary ammonium material of the formula: wherein each R¹ group is independently selected from C₁₋₄ alkyl, alkenyl or hydroxyalkyl groups; each R² group is independently selected from C₈₋₂₈ alkyl or alkenyl groups; T is and n is an integer with a value from 0 to 5; and (ii) at least 0.5% by weight of an extender material, which is a mixture of (a) an ester-linked mono-long alkyl or alkenyl quaternary ammonium compound containing a single long C8-28 alkyl or alkenyl group linked to the quaternary ammonium molecule via an ester linkage; and one or more compounds of: (b) a tertiary amine containing one C8-28 alkyl or alkenyl group and two C1-4 alkyl, alkenyl or hydroxyalkyl groups; (c) a predominantly linear non-ionic ester material; (d) a predominantly linear C8-28 fatty alcohol material, a C8-28 fatty acid material or a salt thereof, or; (e) an ester of a predominantly linear C8-18 fatty acid with a polyhydric alcohol; wherein the dispersion has an average particle diameter of less than 10 µm and a pH value of less than 8.0. 3. A fabric softener according to any one of claims 1 or 2, containing at least 8% by weight of the ester-bonded quaternary ammonium material of formula I. 4. A fabric softener according to any preceding claim, wherein the ester-linked mono-long alkyl or alkenyl quaternary ammonium compound is selected from materials of formula II or the formula III R² wherein R¹, R², T and n are defined for the formula I and R³ is hydrogen or a hydroxy group. 5. A laundry softener according to any one of the preceding claims having a pH in the range from 2 to 8.