GB2239873A - Non-aqueous liquid detergents - Google Patents

Abstract

A slurry of solid materials having a relatively high surface area dispersed in a non-aqueous medium is used in the preparation of a non-aqueous liquid detergent composition.

Description

SLURRIES AND THEIR USE IN MAKING LIOUlD DETERGENT COMPOSITIONS This invention relates to non-aqueous slurries and a method of using such slurries in the preparation of nonaqueous liquid detergent compositions.

Non-aqueous liquid detergent compositions, such as for fabric washing, have been described in the art.

Generally, they contain a liquid phase in which one or more solid phase ingredients in particulate form are suspended. A surfactant is included, most conveniently but not necessarily by the use of a liquid surfactant as part or all of the liquid phase. The solid phase ingredients include a detergency builder or builder system. Where the use of excessive amounts of phosphate is to be avoided a suitable builder system is a mixture of a water-soluble carbonate material and calcite. This is a particularly useful builder system because of its relatively low cost and due to the fact that when a peroxygen bleach system is also present, bleach stability may be better than the case when, for example, aluminosilicates are used as non-phosphate builders.

A problem in using solid materials having a high surface area say more than 25m2/g, for example 35-200 m2/g, especially 50-150 m2/g, is that the fine particles can introduce handling and transportation difficulties.

These problems are especially apparent when calcite materials having a high surface area are used, but sometimes they are also observed by using other materials of relatively high surface area such as silica materials, especially finely divided silica materials, in particular hydrophobically modified silica materials such as Sipernat D10 or Sipernat D17 ex Degussa, or metal oxides such as for example finely divided Magnesium or Calcium oxides, clay materials in particular finely divided'hydrophilic or hydrophobic clay materials, bleaches such as finely divided perboratemonohydrate bleaches and builders such as for example non-phosphate builders, in particular zeolite and/or citrate builders.

We have now discovered that solid materials having a relatively high surface area, such as calcite, can be stably dispersed in a non-aqueous medium to form a slurry and that this slurry can be successfully used in the preparation of non-aqueous liquid detergent compositions.

Thus, according to one aspect of the invention, the present invention relates to the use of a slurry of solid materials having a relatively high surface area dispersed in a non-aqueous medium in the preparation of a non-aqueous liquid detergent composition. Preferably calcite or the other materials as referred to above are used as solid materials. Thus according to a second aspect of the invention, the present invention relates to the use of a slurry of calcite, silica, clay, bleach and/or builder dispersed in a non-aqueous medium in the preparation of a non-aqueous liquid detergent composition.

Thus, according to a third aspect of the invention, there is provided a method of preparing a non-aqueous liquid detergent composition comprising a surfactant and a material of relatively high surface area, the composition being in the form of a particulate solid phase dispersed in a liquid phase, the method comprising the use of a slurry of the material of relatively high surface area in a non-aqueous liquid medium.

In the remaining of this specification the use of calcite slurries as preferred in accordance with the present invention is discussed, for the use of slurries containing solid materials other than calcite similar conditions apply.

Usually, when calcite slurries are used, the nonaqueous liquid detergent compositions to be made by the above methods additionally contain one or more further solid phase ingredients. These may be selected, for example, from other detergency builders, alkali metal carbonates, enzymes, bleaches and bleach activators, fabric conditioning agents, fluorescers, dyes, perfumes, soil suspending agents, corrosion inhibitors, enzyme stabilizing agents and lather depressants.

Advantageously in the forming of the final liquid detergent composition, these further solid phase ingredients will be mixed with the calcite slurry.

Although sometimes, for example for increasing the stability of the slurry, it may be advantageous that the slurry comprises one or more of the additional ingredients intended to be present in the final detergent composition, it is preferred that the majority of the materials other than calcite and the liquid medium are not yet present in the slurry. Based on the total weight of the materials other than calcite and the liquid medium, preferably at least 50 8 of these materials, more preferably more than 75 wt %, most preferably more than 90 % will be added in the final preparation step. Preferably the level of ingredients other than calcite and the liquid medium will be less than 10 % by weight of the slurry, more preferred from 0- 5 %, most preferably from 0.1 to 3 %.

Preferably liquid detergent compositions prepared as described above comprise a water-soluble carbonate material, which is prefera7)ly selected from the carbonates and bicarbonates of sodium and potassium, or mixtures thereof, although any water-soluble carbonate material is suitable. Most preferred is a mixture of sodium carbonate and bicarbonate, or sodium sesquicarbonate, which generates good building capacity in hard water without excessive alkalinity. Preferably the level of water-soluble carbonate is from 0-35% by weight, more preferably 2-30%, most preferably 5-25%.

The liquid medium of the slurry preferably comprises a liquid surfactant, in particular a liquid non-ionic surfactant, more preferably an alkoxylated fatty alcohol, most preferably an EO (2-12), ethoxylated (7-20) alcohol. Other liquid phase ingredients may also be present in the final liquid detergent product, especially liquids which act for example as soil solvents or bleach activators.

In addition to the solid phase ingredients which are mixed into the calcite slurry, any other liquid phase ingredients may be added at this stage or alternatively they may be included in the calcite slurry.

We have found that calcite slurries in nonionic surfactants can be formed with satisfactory rheological properties. Preferably the content of calcite in the slurry is more than 2 % and less than 60 % by weight such as from 10-50 %, more preferably from 15-45 %, most preferably from 20-40%. These levels are also preferred when other materials of relatively high surface area are used.

Therefore a preferred embodiment of the invention relates to a non-aqueous slurry consisting of: (a) 2-60 % by weight of a material of relatively high surface area; (b) a liquid non-aqueous medium; and (c) less than 10 % by weight of ingredients other than the material of relatively high surface area and non-aqueous medium.

It is useful to include in the slurry, a suspension stabilizing agent to reduce or prevent separation of the liquid and solid phases (settling) and to prevent the build up of undesirably high viscosities (setting). Such agents are described in European Patent Specification EP 266199 (Unilever) as "deflocculants". Most preferred is the use of anionic surfactants, especially anionic surfactants in acid form. Preferably the level of deflocculants is from 0.1-5 % by weight of the slurry, more preferred 0.2-4 %.

Therefore another preferred embodiment of the invention relates to a non-aqueous slurry consisting of: (a) 10-50 % by weight of a material of relatively high surface area; (b) a liquid non-ionic surfactant; and (c) 0.1 to 5 % by weight of deflocculant material, and the slurry comprises less than 10 % by weight of ingredients other than the material of relatively high surface area and non-ionic surfactant.

The nature of the various ingredients which may be used to make up the detergent compositions and the levels at which they may suitably be used, are described in EP 266199 referred to above.

The slurries according to the invention may be prepared by addition of the dry calcite or other material of high surface area to a stirred vessel containing the nonaqueous medium. Ingredients other than the calcite may be added before, at the same time or after the addition of the calcite to the liquid medium. Generally no milling step will be necessary to prepare the slurry.

After preparation the slurry may be stored, transported etc, finally the slurry may be used in the preparation of a non-aqueous liquid detergent composition by combining the slurry with the remaining ingredients of the composition.

PROCESSING During manufacture, it is preferred that all raw materials should be dry and (in the case of hydratable salts) in a low hydration state, e.g. anhydrous carbonate builder, sodium perborate monohydrate and dry calcite. In a preferred process, the dry, substantially anhydrous solids are blended with the calcite slurry in a dry vessel. In order to minimise the rate of sedimentation of the solids, this blend is passed through a grinding mill or a combination of mills, e.g.

a colloid mill, a corundum disc mill, a horizontal or vertical agitated ball mill, to achieve a particle size of 0.1 to 100 microns, preferably 0.5 to 50 microns, ideally 1 to 10 microns. A preferred combination of such mills is a colloid mill followed by a ball mill since these can be operated under the conditions required to provide the appropriate size distribution in the final product. Of course particulate material already having the desired particle size need not be subjected to this procedure and if desired, can be incorporated during a later stage of processing.

During this milling procedure, the energy input results in a temperature rise in the product and the liberation of air entrapped in or between the particles of the solid ingredients. It is therefore highly desirable to mix any heat sensitive ingredients into the product after the milling stage and a subsequent cooling step.

It may also be desirable to de-aerate the product before additlon of these (usually minor) ingredients and optionally, at any other stage of the process. Typical ingredients which might be added at this stage are perfumes and enzymes, but might also include highly temperature sensitive bleach components or volatile solvent components which may be desirable in the final composition. However, it is especially preferred that volatile material be introduced after any step of daeration. Suitable equipment for cooling (e.g. heat exchangers) and de-aeration will be known to those skilled in the art. It follows that all equipment used in this process should be completely dry, special care being taken after any cleaning operations. The same is true for subsequent storage and packing equipment.

Examples 1-4 Calcite slurries having the compositions (% by weight) given below were prepared by addition of the dry calcite to a stirred vessel containing the nonionic detergent material and -in example 4- the deflocculant material.

Each slurry was stored for 4 weeks at 370C and the viscosity was measured at 21s-1. After this period, phase separation (setting) was minimal. The results shows that the slurries had satisfactory rheological properties.

Example No: 1 2 3 4 Inaredients Calcitel 21 24 28 38 ABSA2 - - - 0.2 Nonionic surfactant3 balance -------------balance----------- Viscosity (mPast 192 312 552 2760 21s- Notes 1 Socal U3 (ex Solvay) having a surface area of 85 m2/gram.

2 C12 alkyl benzene sulphonic acid (stabilizing agent).

3 A narrow range 6 EO ethoxylated C10-12 alcohol ex Vista Chemical Company.

These slurries were then used to prepare the following non-aqueous liquid detergent composition by mixing the ingredients (except for the perfumes and enzymes) in the listed order, followed a milling step in a colloid mill followed by milling in a ball mill.

Finally the perfume and enzyme ingredients are added.

Ingredient (t wt) A Nonionic (ex Vista see above) 28.9 Anionic (L (C12-14)AS) 3.9 Na carbonate 18.0 GTA (glycerol triacetate) 5.7 Silicone DB 100 1.0 Na bicarbonate 4.2 Slurry (see example 4) 21.0 TAED 3.0 Perborate.monohydrate 10.5 Enzymes 0.8 Perfume 0.5 Minor ingredients (fluorescers balance anti-reposition acids) Example V A slurry of hydrophobically modified silica material was prepared by addition of the dry silica to a stirred vessel containing the nonionic detergent material.

Ingredient (% wt) Nonionic surfactantl) 85 % Sipernat D17 (ex Degussa) 15 % 1) Synperonic A7 ex ICI This slurry was used for the preparation of a liquid detergent composition of the following composition: Ingredient (% wt) B Nonionic (ex Vista see above) 35.0 Anionic (L (C12-14)AS) 3.9 Na carbonate 18.0 GTA (glycerol triacetate) 8.7 Silicone DB 100 1.0 Na bicarbonate 6.2 Sipernat Slurry 12.0 TAED 3.0 Perborate.monohydrate 10.5 Enzymes 0.8 Perfume 0.5 Minor ingredients (fluorescers balance anti-reposition acids)

Claims (1)

1. CLAIMS 1. The use of a slurry of solid materials having a relatively high surface area dispersed in a non aqueous medium in the preparation of a non-aqueous liquid detergent composition.