GB2096163A - Built detergent bars - Google Patents

Abstract

Built detergent bar intended for laundry use are required to satisfy commercial user requirements. Extruded bars prepared using the invention contain a filler system comprising a sheet alumino-silicate filler, e.g., bentonite, and a water soluble non-builder filler material, e.g. sodium sulphate.

Description

SPECIFICATION Built detergent bars FIELD OF THE INVENTION This invention relates to improved extruded 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.

GENERAL DESCRIPTION OF THE INVENTION The invention provides an improvement in extruded 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 10% to about 60% by weight of at least one non-builder substantially water soluble filler, the mixed filler system forming from about 10%, preferably above about 20%, to about 50% by weight of the detergent bar.

The substantially water soluble filler is required to be a non-builder material, that is it does not interact in the wash liquor to reduce the levels of hardness ions. Usually it will be an inorganic salt.

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.

The filler systems of the invention provide an increase in bar strength with a commercially acceptable rate of wear. 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 cane accommodated.

Preferably the water soluble filler is selected from chloride, sulphate, bicarbonate, borate and mixtures thereof. The sheet alumino-silicate filler is preferably selected from bentonite, kaolin and mixtures thereof. The water soluble fillers will usually be the alkali metal, preferably sodium, or ammonium salts.

Commercially preferred products will contain from about 10% to about 40% by weight of the builder material. The fillter 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 extent 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.

PRIOR LITERATURE UK 1,175,749 (Altieri) describes the manufacture of detergent formulations in cake form by compression of a powder. The presence of soluble filler (bicarbonate and sulphate) and bentonite is disclosed in Example 2. There is no disclosure of the benefit obtained when the mixed filler system of the present invention is used in an extruded product. An extruded bar is normally prepared by milling and plodding.

COMPONENTS OF THE FORMULATION Detergent active and builder components are well characterised in detergent bar technology.

These components are characterised in "Surface Active Agents" by Schwarz and Perry (Interscience 1949) and volume II by Schwarz, Perry and Berch (Interscience 1958). The detergent actives usable are found in the general classes.of anionic, nonionic, amphoteric, betaine and zwitterionic actives. Specific examples of detergent active are linear alkyl benzene sulphonates, alkane sulphonates, alcohol sulphates, branched alkyl benzene sulphonates, alkyl sulphates, olefin sulphonates, monocarboxylic acid salts and ethoxylated alcohols.

Examples of builder components are: water soluble phosphate salts, e.g. sodium tripolyphosphate, pyrophosphate and orthophosphate; water soluble carbonates, e.g. sodium carbonate; organic builders e.g. sodium nitrilo-triacetate, sodium tartarate, trisodium carboxy-methyl oxysuccinate, sodium oxydisuccinate and sodium sulphonated long chain monocarboxylic acids.

Other ingredients, for example all < aline salts, e.g. sodium alkaline silicates, starch, sodium carboxymethylcellulose, colouring materials, fluorescers, opacifiers, germicides, perfumes and bleaching agents, are optionally added. Silicates fall within the definition of builder salts.

The water soluble 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. Quantitites 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 9010' and was forced into the disc centre, the disc being supported on a flat smooth surface, under a pressure of 100 g 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 21 inch diameter. The rods were weathered under ambient conditions (220C to 240C) for a minimum of 5 days.

An Instron tensile tester Bench top modei 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 (22 OC to 240C). The bar was held against cylinders spaced 22 cm apart by a forced 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 E0 was calculated using standard physical equations.

iii) 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 in the rate of wear (R) in grms.

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

Test formulations used were based on sodium alkyl (branched) benzene suiphonate as active and sodium pyrophosphate as builder the total amount of filler system was 37%.

Formulation: Weight % Component Sodium alkyl (C11-C13) branched 28 benzene sulphonate Sodium pyrophosphate 1 6 Sodium carbonate monohydrate 10 Fillers (bentonite/soluble filler) 30 Sodium carboxy methyl cellulose 2 Sodium sulphate (anhydrous) 7 Added water 7 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 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 800C. 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.

The formulation was used as a base to study a filler system having sodium sulphate, sodium bicarbonate, sodium borate (Na2B4O7. 10H20) and sodium chloride as soluble fillers and bentonite as the sheet alumino-silicate filler respectively. The amount of sodium sulphate (7%) derived from processing the base formulation was kept constant and the amounts of soluble filler and bentonite varied.

The results for E0 (measured in Newtons per square metre) and Rate of Wear (R measured in grms) are given in the Tables.

EXAMPLE I Amount of filler in formulation (%) Sodium bicarbonate Bentonite E0 R 30 nil 8.3 x 108 1.58 20 10 10.2x108 1.84 10 20 14.4x108 2.12 nil 30 14.3 x 108 3.26 These bars had acceptable product and in-use properties.

EXAMPLE II Sodium sulphate (anhydrous) was used as the soluble filler; this was in addition to the sulphate (7%) derived from processing.

Amount of filler in formulation (1%) Sodium sulphate Bentonite E0 R 30 nil 6.1 x 108 2.3 20 10 10.5 x 108 2.7 10 20 13.6 x 108 3.2 nil 30 14.3 x 108 3.6 These bars had acceptable product and in-use properties.

EXAMPLE lil Sodium borate was used as the soluble filler; the bars had acceptable product and in-use properties.

Amount of filler in formulation (%) Sodium borate Bentonite E0 R 30 nil 7.0 x 108 1.4 20 10 10.7x108 1.9 10 20 12.5 x 108 2.5 nil 30 14.3 x 108 3.1 EXAMPLE IV Sodium chloride was used as the soluble filler; the bars had acceptable product and in-use properties.

Amount of filler in formulation (%) Sodium chloride Bentonite E0 R 30 nil 5.5 x 108 1.8 20 10 8.3x108 2.4 10 20 11.3 x 108 2.9 nil 30 14.3 x 108 3.4

Claims (9)

1. An extruded detergent bar 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 characterised in that the bar contains from about 0.5% to about 45% of at least one sheet alumino-silicate filler and from about 10% to about 60% of at least one non-builder substantially water soluble filler, the mixed filler system forming from about 10% to about 50% by weight of the detergent bar.

2. A detergent bar according to claim 1 containing at least about 1.5% of the sheet alumino siiicate filler.

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

4. A detergent bar according to any preceding claim wherein the sheet alumino-silicate filler is present at a level up to about 50% by weight of the filler system.

5. A detergent bar according to claim 4 wherein the sheet alumino-silicate is present at a level up to about 40% by weight of the filler system.

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

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

8. A detergent bar according to any preceding claim wherein the soluble filler is selected from chioride, sulphate, bicarbonate, borate and mixtures thereof.

9. A detergent bar according to any preceding claim containing at least about 20% of the mixed filler system.