GB2060676A - Built detergent bars - Google Patents

Abstract

Built detergent bars are used in cleaning and laundering. The improved bars of the invention include a filler system which comprises a mixture of a particulate filler and a sheet alumino-silicate filler. The use of the filler system provides good bar properties i.e., bar strength and rate of wear. The product formulator is given more flexibility in varying the amounts of other components.

Description

SPECIFICATION Built detergent bars FIELD OF THE INVENTION This invention relates to improved built detergent bars. Detergent bars used, for example, for fabric washing and cleaning surfaces should have certain properties so they can perform their required functions. The bars must have a good bar strength to ensure the product retains its integrity during handling and transport. During use the bulk of the bar is removed from the surface to provide cleaning and washing components; excessive removal of the components at the surface means the rate of wear of the bar is above that which a user would associate with efficient use of the bar.

Commercial detergent bars contain detergent active material, and detergency builder material with a number of optional components, for example abrasives, fillers, perfumes, alkaline salts and bleaching agents.

GENERAL DESCRIPTION OF THE INVENTION The invention provides an improvement in built detergent bars in commercial use comprising from about 7% to about 45% by weight of detergent active material and from about 5% to about 60% by weight of detergency builder. Detergent bars of this type are characterised by containing from about 0.5% to about 45% by weight of at least one sheet alumino-silicate filler and from about 2.5% to about 57% by weight of at least one particulate substantially water insoluble non-sheet-alumino-silicate filler, the mixed filler system forming from about 10% to about 60% by weight of the detergent bar.

These amounts of sheet alumino-silicate filler and particulate non-sheet-alumino-silicate filler measured relative to the total bar formulation correspond to about 5% to about 75% of the sheet alumino-silicate filler and from about 25% to about 95% of the particulate non-sheet alumino-silicate filler measured as proportions of the filler system which forms from about 10% to about 60% by weight of the total bar.

The particulate filler is required to be a filler other than a sheet alumino-silicate. Therefore it includes fillers which are in sheet form but are not alumino-silicates in addition to alumino-silicates which are not in sheet form. Particulate fillers which are neither in sheet form nor alumino-silicates are included. Preferably the lower limit of the range of sheet alumino-silicate is about 1.5%. Preferably the sheet alumino-silicate filler has a penetration of less than about 1.8 mm in the penetration test defined.

The amount of sheet alumino-silicate filler is preferably up to about 50% by weight of the filler system at which level the benefit obtained by adding further sheet alumino-silicate filler reduces relatively sharply.

The filler systems of the invention provide an increase in bar strength with a commercially acceptable rate of wear. The applicants have found the bar strength reaches a maximum more rapidly than the rate of wear as the proportion of sheet alumino-silicate filler in the filler system is increased.

Above about 75% of sheet alumino-silicate filler in the filler system the bar strength remains substantially constant while the rate of wear continues to rise. In general about 40% by weight of sheet alumino-silicate is the preferred maximum in the total filler system. The filler systems of the invention were particularly effective in maintaining the bar properties in conditions of high temperature and humidity.

These systems allow an increased flexibility in product formulation while retaining the commercially acceptable bar properties, for example increases in active level, and, optionally, associated reduction in builder level can be accommodated.

Preferably the particulate filler is selected from calcite, feldspar, dolomite and mixtures thereof.

The sheet alumino-silicate filler is preferably selected from bentonite, kaolin and mixtures thereof. The particulate fillers exclude sheet alumino-silicates and thus include alumino-silicates having a form other than sheet and sheet minerals, other than alumino-silicates.

Commercially preferred products will contain from about 10% to about 40% by weight of the builder material. The filler system of the invention allows the amounts of the active material and builder material, together with other components of the bar, to be varied while maintaining the product bar properties within the desired commercial specification. Thus changes in the amounts and proportions of the active and builder materials can be balanced at least to some exterit by changes within the filler system.

The applicants have appreciated the materials acknowledged as fillers can be utilised to obtain a balance of the required product properties when used in the filler systems of the invention.

COMPONENTS OF THE FORMULATION Builder and detergent active components are well characterised in the field of detergent bar technology. Examples of these components are listed hereafter and full descriptions of these and other examples of these components will be found in "Surface Active Agents" by Schwartz 8 Perry published by Interscience (1949) and volume II by Schwartz, Perry and Berch published by Interscience (1958).

Examples of detergent actives usable in the built compositions of the invention are present in the general classes of anionic, nonionic amphoteric, betaine and cationic actives. Specific classes usable singly or in admixture are: a) Fatty acid ester sulphonates having from about 8 to about 20 carbon atoms in the fatty acid chain; b) alkali metal salts of alkane sulphonates having an alkyl chain length of from 11 to 14, these actives can be prepared by the reaction of a bisulphite ion species with an olefin; c) sulphates of branched chain alcohois having chain lengths from 1 2 to 1 5, these alcohols are obtainable under the trade name "Dobanol"; d) alkylaryl sulphonates having an alkyl chain from C10 to Cas;; e) dialkali metal salts of sulphonated saturated fatty acids having a chain length from C12 to C20; f) ethoxylated alcohols (C12 to C20) having a degree of ethoxylation between 10 and 20: g) alkyl (C12 to C18) sulphates, wherein the alkyl group is branched or linear; h) alkene sulphonates having a chain length from C14 to C24; i) alkali metal salts of C8 to C22 long chain fatty acids; and j) nonionic detergent actives, for example polyoxy-alkylene derivatives of alcohols, alkyl amides and alkanol-amides, polyoxyalkylene esters of acids, alkylene oxide block polymers (eg PLURONICS), polyol esters and acyl alkanolamides.

Specific examples of the builder component are: Water soluble phosphate salts, eg sodium tripoly phosphate, pyrophosphate and orthophosphate; Water soluble carbonate salts eg sodium carbonate; Organic builders eg sodium nitrilotriacetate, sodium tartarate, trisodium carboxymethyloxysuccinate, sodium oxydisuccinate and sodium sulphonated long chain (C14 to C20) fatty acids.

Other ingredients, for example sodium alkaline silicates, starch, sodium carboxymethylcellulose, colouring materials, fluorescors, opacifiers, germicides, perfumes and bleaching agents, are optionally added.

The particulate and sheet alumino-silicate fillers will be ground if necessary to ensure the particle size is suitable for incorporation in a detergent bar.

There are no specific requirements in the methods used to prepare the bars of the invention. A number of methods are known in the art and these methods are suitable for manufacture of bars with filler components of the system being added at a suitable stage.

TEST METHODS The preferred sheet alumino-silicate fillers are defined by reference to a penetration test and bar properties are measured by reference to rate of wear of the bar and the Youngs modulus of the bar composition.

i) Penetration test: The preferred sheet alumino-silicates for use in the filler systems described herein are identified by measuring the penetration properties of a mass of the sheet alumino-silicate. Quantities of sheet alumino-silicate (80% by weight) and water (20% by weight) were mixed to form a moist powder at room temperature. The powder was placed in a disc mould having a diameter of 3 cm. The powder was subjected to a pressure of 2 tons for 5 seconds; the resulting disc had a diameter of 3 cm and a depth of 1.2 cm and was stored in an airtight bag for 1 day to allow the disc to equilibrate.

The penetrometer used was a SUR penetrometer type PNR 8 (Manufactured by Sommer and Runge of Berlin DBR). The penetration needle had a point angle of 90 1 0' and was forced into the disc centre, the disc being supported on a flat smooth surface, under a pressure of 1009 for 10 seconds.

It was found that sheet alumino-silicates having a penetration below about 1.8 mm were preferred for use in the filler systems of the invention.

ii) Youngs modulus has been found to give a consistent measure of the bar strength. To measure Youngs modulus (Eo) the bar composition was extruded in the form of 25 cm rods having z inch diameter. The rods were weathered under ambient conditions (220C to 240 C) for a minimum of 5 days.

An Instron tensile tester Bench top model 1026 (manufactured by Instron Ltd of High Wycombe, England) was used. The rods were cut to 23.5 cm and bent in the instron device at room temperature (220C to 240 C). The bar was held against cylinders spaced 22 cm apart by a force applied by a hook connected to a load cell. The hook was drawn towards the load cell at a rate of 0.5 mm per minute while a recorder recorded the displacement or time against the force applied. The maximum force required at breaking point and the corresponding displacement were noted.

From these measurements the value of Eo was calculated using standard physical equations.

ii) Rate of wear test: A cloth was placed on a smooth surface which was inclined to extend below the surface of water in a trough. A detergent bar was placed on the cloth, contracting it at a face having an area of 5 cm by 3 cm with the 5 cm dimension positioned across the slope. The bar was moved up and down the plane under a force of about 1 90 g tracing a path of 6.5 cm of which about half extended below the water level.

The bar was subjected to 125 cycles (a cycle being two strokes, one in each direction) with a new cloth being used for each period of 25 cycles.

The loss in weight after the bar had been dried at ambient overnight is the rate of wear (R) in grams.

DRAWINGS This specification is accompanied by 6 figures which carry graphs showing the Youngs modulus and rate of wear of detergent bars including the filler systems of the invention. The graphs display the results given in the examples and the content of each graph is noted in the appropriate example.

EXAMPLES Examples of detergent bars according to the invention will now be described to illustrate but not limit the invention.

Two test formulations used were based on sodium alkyl (branched) benzene sulphonate as active and sodium pyrophosphate as builder. In formulation A the amount of filler system was 30% and in Formulation B it was 40%. The two formulations are given in Table I with the amounts in percentage by weight.

TABLE I Formulation Component A B Sodium alkyl (C11-C13 branched chain) 28 22 benzene sulphonate sodium pyrophosphate 16 11 sodium carbonate monohydrate 10 10 filler system 30 40 sodium carboxy methyl cellulose 2 1 sodium sulphate (anhydrous) 7 6 added water 7 10 A quantity of the alkyl (branched) benzene sulphonic acid sufficient to give the required amount of sulphonate active was heated to 350C and the sodium carbonate added; the whole was mixed for 5 minutes. The formulation water was then added and mixing continued for 10 minutes. The other components were then added in sequence with a period of mixing at each addition. The components of the filler system were premixed and half the quantity added and mixed for 3 minutes, the other half of the filler was then added and mixing continued for 3 minutes.The sodium sulphate (additional to that already present in the active to give the required level) and SCMC were mixed together, added and mixed for 5 minutes. The sodium pyrophosphate builder component was then added with additional mixing of 1 5 minutes. The formulation was milled twice and plodded three times with the temperature of the final apertured plate of the plodder maintained at 800 C. The formulation was prepared in batches of 1 5 Kg. The major proportion of each batch was extruded and formed into commercially sized bars.

Samples were extruded for measurement of Youngs modulus and rate of wear.

EXAMPLE I Formulation A was used as a base to study a filler system having calcite and bentonite as the particulate and sheet alumino-silicate fillers respectively. Calcite of grade D.40, obtainable from Omya SA of France, and having a mean particle size distribution of 40 micron was used in admixture with bentonite.

The results for Eo (measured in newtons per square metre) and Rate of Wear (R measured in grms) are given in Tables II.

TABLE II TABLE II Amount of filler in formulation (%) Calcite Bentonite Eo R 30 nil 6.36 x 108 1.76 28.5 1.5 7.92 x 108 1.46 27 3 8.71 x 108 1.90 24 6 9.58 x108 1.88 18 12 12.68 x108 2.28 nil 30 13.80 x 108 3.28 These results are shown graphically in Figure 1.

These bars had acceptable product and in-use properties and it will be seen the bar strength increases relatively rapidly when low amounts of bentonite are present while the rate of wear increases at a substantially constant rate.

EXAMPLE II Formulation A was used to study the filler system comprising dolomite and bentonite.

The results of bar tests for Eo and R are given in Table Ill.

TABLE III Amount of filler in bar (%) Dolomite Bentonite Eo R 30 nil 7.84 x 108 1.62 28.5 1.5 8.71 x 108 1.81 18 12 13.06 x 108 2.23 nil 30 13.80 x 108 3.28 These results are shown graphically on Figure 2.

These bars had satisfactory product and in-use properties and it will be seen the Youngs modulus increases relatively rapidly at low levels of bentonite while the rate of wear increases at a substantially constant rate.

EXAMPLE Ill Example II was repeated using feldspar as a replacement for the dolomite. The results are given in Table IV and shown graphically on Figure 3.

TABLE IV Amount of filler in bar (%) Feldspar Bentonite Eo R 30 nil 6.18x108 1.84 28.5 1.5 8.06 x 108 1.72 18.0 12 12.19x108 2.60 nil 30 13.80 x 108 3.28 It will be seen the properties of this bar are comparable to those of Example II.

EXAMPLE IV Formulation A was used to study a filler system comprising calcite and kaolin. The calcite was of the type used in Example I. The results of the measurements on this formulation are given in Table V and shown graphically on Figure 4.

TABLE V Amount of filler in bar (%) Calcite Kaolin Eo R 30 0 6.36 x 108 1.76 27 3 9.47 x 108 2.23 18 12 13.2Ox108 2.58 0 30 13.15x108 2.96 The presence of relatively low levels of kaolin causes an increase in bar strength with a relatively small increase in the rate of wear.

EXAMPLE V Formulation B was used to test a number of filler systems according to the invention. The formulations and test results are given in Table VI.

TABLE VI Amount of filler in bar (%) Sheet alumino Particulate silicate Eo R Calcite 40% nil 6.26 1.94 Calcite 36% bentonite 4% 10.75 2.11 Calcite 30% bentonite 10% 13.06 2.22 nil bentonite 40% 15.24 2.98 Dolomite 40% nil 8.71 2.53 Dolomite 36% bentonite 4% 12.80 2.55 Feldspar 40% nil 5.68 2.58 Feldspar 36% bentonite 4% 11.31 2.57 The results for the calcite/bentonite filler system are also shown graphically on Figure 5.

It is seen the presence of a small amount of a sheet alumino-silicate filler increases bar strength with only slight effect on rate of wear.

EXAMPLE VI Formulation A was used as a base to study a filler system having calcite and mica as the particulate and sheet alumino-silicate fillers respectively. The calcite used was of grade D40, obtainable from Omya SA of France, and having a mean particle size distribution of 40 micron. The mica was obtained from Microfine Minerals and Chemicals Ltd of Derby England and had at least 60% of the particies finer than 60 micron (measured by sedimentation).

The results for E0 (newtons per square metre) and Rate of Wear (grms) are given in Table VII and are shown graphically in Figure 6.

TABLE VIZ Amount of filler in bar (%) Calcite Mica E0 R 30 0 6.3x108 1.76 20 10 8.5x1O8 1.85 10 20 9.62 x 108 2.04 0 30 9.80 x 108 2.26

Claims (9)

1. A detergent bar comprising: i) from about 7% to about 45% by weight of a detergent active material, and ii) from about 5% to about 60% by weight of detergency builder material, characterised in that the bar contains iii) from about 0.5% to about 45% by weight of at least one sheet alumino-silicate filler and from about 2.5% to about 57% by weight of at least one particulate substantially water insoluble non-sheetalumino-silicate filler, the mixed filler system forming from about 10% to about 60% by weight of the detergent bar.

2. A detergent bar according to claim 1 wherein the lower level of sheet alumino-silicate filler is about 1.5% by weight.

3. A detergent bar according to claim 1 or 2 wherein the sheet alumino-silicate has a penetration of less than about 1.8 mm in the penetration test described.

4. A detergent bar according to any preceding claim wherein the amount of sheet alumino-si!icate filler is not more than about 50% by weight of the mixed filler system.

5. A detergent bar according to claim 4 wherein the amount of sheet aluinino-silicate filler is not more than about 40% by weight of the mixed filler system.

6, A detergent bar according to any preceding claim wherein the particulate filler is selected from calcite, feldspar, dolomite and mixtures thereof.

7. A detergent bar according to any preceding claim wherein the sheet alumino-silicate filler is selected from bentonite, kaolin and mixtures thereof.

8. A detergent bar according to any preceding claim containing from about 10% to about 40% of builder material.

9. A detergent bar according to claim 1, substantially as described in any of Examples I to VI.