Classifications

• • C—CHEMISTRY; METALLURGY
  • C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
  • C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
  • C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
  • C11D3/39—Organic or inorganic per-compounds
  • C11D3/3902—Organic or inorganic per-compounds combined with specific additives
  • C11D3/3905—Bleach activators or bleach catalysts
  • C11D3/3907—Organic compounds
  • C11D3/3917—Nitrogen-containing compounds
  • C11D3/392—Heterocyclic compounds, e.g. cyclic imides or lactames

Definitions

• This invention relates to a method of improving the performance of water-stable bleach activators and to formulations containing such activators of improved performance.
• Bleach activators are well known ingredients of detergent formulations.
• a widely used activator is tetraacetyl ethylene diamine (also known as TAED) which is described in GB-A-2832021.
• Bleach activators which have an anhydride structure have recently been used in detergent formulations. Such activators are claimed and described in our published EP-A-331300. These activators are primarily based on the isatoic anhydride (hereafter referred to as "IA" in the specification) type structure. The use of similar anhydrides is also claimed in the later filed EP-A-332050 (Henkel). Similarly activators which have a lactone structure have been claimed and described in our published EP-A-332294.
• EP-A-332050 states that IA or its derivatives can be used for activation in pure form, or to improve storage stability it can be added as tablets, granules, or in finely divided coated form. This patent specification adds, however, that special significance is attached to the granulated form which is prepared by agglomeration of powder.
• Granulation is a process for binding active material powders together into e.g. agglomerates. This technique usually mitigates problems of dust and materials handling and bestows other advantages such as improvement of flow; prevention of lump or cake formation; ease of metering, dosing and dispensing; enabling formation of uniform mixtures/blends without risk of segregation of the components in the mixture/blend; stabilisation of the active materials against premature degradation; controlling the release profile of the active materials; and enabling coatings to be applied on the active materials.
• the present invention relates to a granulated bleach activator formulation comprising:
• the present invention relates to a granulated bleach activator formulation comprising on a dry weight basis:
• the amount of bleach activator in the granulated formulation is suitably at least 60%w/w, preferably at least 70%w/w.
• the particle size of the powdered bleach activator used to produce the granules is below 250 micrometers, suitably below 150 micrometers, preferably from 1-110 micrometers. It has been found that some commercial varieties of activators sold and used in detergent formulations may have a particle size outside this range. In such a case, the activator has to be milled or ground to bring the particle size within the range now specified followed by air classification or sieving to produce a powder of the desired particle size range. Otherwise, the formulations of the invention do not function effectively since the use of larger particles for granulation in the case of e.g. IA cause yellow-brown colouration of the wash liquor and can in some cases cause staining of the clothes washed therewith. If, however, the activator is available in the appropriate particle size it can be used directly to produce the granulated formulations of the present invention.
• the granulated formulations of the present invention can optionally include conventional bleach activators such as tetralkyl ethylenediamine in addition to the compounds of formula (I) or (II) provided that the particle size of powder comprising such mixed activators used in the formulation to be granulated falls within the ranges now specified.
• conventional bleach activators such as tetralkyl ethylenediamine
• the binder used is a clay, suitably a bentonite clay, preferably an alkali metal bentonite clay or an alkaline earth metal bentonite clay. Most preferred are the sodium and calcium forms of bentonite clay.
• the amount of binder used in the formulation is suitably from 5-20%w/w, preferably 5-15%w/w of the dry granules.
• a disintegrating aid in the granulated formulation facilitates the disintegration of the activator present in the formulation into the wash liquor. This is usually achieved by the ability of the disintegrating aid to swell in the presence of excessive amounts of water, as would be encountered during a wash cycle, and thereby help break up the granules to release the activator.
• the disintegrating aid can also be used to partially or wholly replace the filler in the formulation.
• the amount of disintegrating aid used in the formulation is suitably from 0-15%w/w, preferably from 2-11%w/w on a dry weight basis of the total formulation. Examples of disintegrating aids that can be used include water swellable caboxymethyl cellulose derivatives such as the cross-linked microcrystalline derivative Ac- di-sol (Regd Trade Mark, ex FMC Corp) and polyacrylates.
• the presence of a filler in the granulated formulation improves the binding properties of the clay binder.
• the filler is suitably present in an amount from 0-20%w/w, preferably from 1-12%w/w.
• examples of fillers that can be used include various conventional inorganic fillers such as sodium sulphate or cellulosic fillers such as e.g. Avicel (Regd Trade Mark, ex FMC Corp).
• the formulations of the present invention may contain in addition surfactants such as e.g. Tween 81 (Regd Trade Mark) which is a polyoxyethylene sorbitan monooleate ester or an alkali metal salt of a polycarboxylic acid, Dispex G40 (Regd. Trade Mark, ex Allied Colloids).
• surfactants such as e.g. Tween 81 (Regd Trade Mark) which is a polyoxyethylene sorbitan monooleate ester or an alkali metal salt of a polycarboxylic acid, Dispex G40 (Regd. Trade Mark, ex Allied Colloids).
• surfactants which can also aid disintegration, can be present in an amount from 0.01-5%w/w, preferably upto 3%w/w.
• 2-aryl 3,1 (4H)-benzoxazin-4-ones When 2-aryl 3,1 (4H)-benzoxazin-4-ones are used, it may be necessary to grind the activator to a very fine powder before being granulated.
• the particle size of the activator powder being granulated should be as small as is possible, preferably below 10 micrometers.
• the preferred surfactant used for 2-aryl 3,1 (4H)-benzoxazin-4-ones is preferably an alkali metal salt, e.g. sodium salt of a polymeric carboxylic acid, e.g. Dispex-G40 (Regd Trade Mark, sold by Allied Colloids, UK), in aqueous solution.
• the surfactant enables dispersion of the fine activator powder in the wash liquor.
• the formulation suitably contains at least one, preferably both the dispersing aid and the filler. However, whichever combination is used, it is preferable that the total amount of the disintegrating aid, the filler and binder used is at least 9%w/w of the total granulated formulation on a dry weight basis.
• the granulated formulations are suitably produced by an extrusion/spheronisation technique.
• Extrusion/spheronisation technique is used to convert an active material in powdered form into regular sized, dense spheres.
• the purpose of this technique is usually to mitigate the problems of dust and materials handling, to allow complete and uniform mixing to be achieved with mixtures of powders without risk of segregation and to enable uniform coatings to be applied.
• the technique consists essentially of (i) mixing a fine powder of the active material with a powdered binder and water to form a crumbly dough, (ii) extruding the dough to form thread-like material from the dough and (iii) placing the extrudate in a spheroniser so as to subject the extrudate to circular and tumbling motion whereby the extrudate is broken up into short pieces which then take the shape of granules.
• the powders can be extruded into a smooth extrudate which (a) is not friable, (b) does not crumble into a dusty powder in the spheroniser and (c) holds the moisture within the mixture thereby reducing stickiness and the risk of agglomeration.
• the extrusion/spheronisation technique is primarily used to produce spheres which: are dense and have a tight particle size distribution; have a relatively smooth surface; enable complete and uniform mixing of the components without risk of segregation; facilitate application of coatings thereon; and protect the active material during storage and transportation.
• the compounds of formulae (I) and (II) as herein defined are water-stable, i.e. they do not substantially disintegrate or substantially undergo any undesirable chemical and/or physical change in the presence of or when exposed to small amounts of water and hence they can be subjected to extrusion/spheronisation in aqueous media.
• An example of such an undesirable change would be the premature decomposition of
• a feature of the invention is that the granulated formulation has a high activator content which enables the bleaching function to be carried out more efficiently in comparison with formulations produced conventionally by extrusion and spheronisation where the activator content is usually much lower and the binder content is relatively high.
• the present invention is a process for producing a granulated formulation from a water-stable, powdered bleach activator, a binder, a disintegrating aid and/or a filler as appropriate and as hereinbefore described, said process comprising subjecting a dough of suitable consistency made from the components of the formulation and an aqueous medium to the extrusion/spheronisation technique.
• the activator, binder and other components of the formulation are thoroughly mixed with the aqueous medium, e.g. water, to form a dough.
• aqueous medium e.g. water
• the pressure required to extrude the mixture might be too high or the extrudate can disintegrate in the spheroniser to a dusty powder; if the liquid level is too low, the mixture can become difficult to extrude; if the liquid level is too high, this may result in stickiness and agglomeration of the mixture in the spheroniser.
• Extrusion involves forcing the dough through a suitable orifice in order to produce continuously a body of uniform cross-section.
• the exact technique for forcing the dough and forming the orifice will vary with the type of extruder.
• one type of extruder that can be used is that which uses a screw to feed the dough to a perforated screen and the dough is extruded through these perforations.
• the dough is fed into a rotating drum in contact with a rotating perforated screen.
• Other devices that may be used include a piston type extruder in which a movable arm squeezes the dough onto a perforated screen.
• Yet another device that can be used is extrusion of a dough by the pressure of a ram through a die.
• the material to be extruded must be in plastic condition. This condition may be achieved by choice of a suitable formulation.
• the size of the orifice would be determined by the ultimate size of the spheres desired and would normally be the approximate final diameter of the spherical product. It would be understood that the particle size of the ingredients forming the dough would be substantially less than the size of the orifice and the particles would ideally be of a diameter which is less than half the diameter of the orifice.
• Sufficient compaction should be achieved during the extrusion phase to ensure adequate 'green' strength in the extrudate. However, the compaction should not be so great that the subsequent spheronisation and, where applicable, disintegration in use are hampered.
• a spheroniser usually consists of a corrugated disc spinning about a vertical axis and the disc is housed in a cylindrical housing with vertical walls along the edges of the disc.
• the extrudate tends to break into smaller pieces and is simultaneously flung towards the walls of the housing by centrifugal force. This action and the dragging action of the corrugations cause the extrudate pieces to spheronise either by impact or by coalescence with other pieces to form the spheres.
• a typical spheroniser is that sold by GB Caleva Ltd.
• the extrudate is placed on a 20.3 cm disc and spun eg at about 1000 rpm for a few minutes to result in a spherical bound product.
• the amount of the extrudate placed on the disc will depend on the size of the disc. Too much or too little of the extrudate will not give optimum spheres.
• the amount of extrudate placed thereon is suitably from 200-1000 g.
• This product is then dried at a temperature from 20-60 °C, preferably around 45 ° C to drive off the surplus aqueous components leaving behind robust spheres.
• formulations used to produce the dense spheres of active materials bound in a binder can also optionally include other ingredients depending upon the end use of the spheres.
• the extrudate was then placed in a 20.3 cm diameter spheroniser (ex GB Caleva Ltd) and spun approximately at 1000 rpm. After about 5 minutes, the extrudate had formed into good spheres being substantially from 500-2000 micrometers in diameter.
• the spheres produced were robust enough to withstand continuous spheronisation of at least 10 minutes without sticking together or breaking down into dusty particles.
• the following granular formulations were prepared and contained an active (IA), a disintegrant (Acdisol) and a binder and/or filler (ASB 60 clay and/or Avicel PH 101 respectively). The components were thoroughly blended together, extruded and spheronised.
• IA active
• Acdisol disintegrant
• ASB 60 clay and/or Avicel PH 101 binder and/or filler
• the following formulations were prepared by using a hand held extruder, which was simply a plate which had an aperture 6mm long and 1 mm in diameter through which the dough prepared as previously was manually extruded, air drying the extrudate and cutting it into prills of 1-2mm lengths;
• This example demonstrates a formula suitable for extrusion/spheronisation containing a 50:50 blend of the bleach activators TAED and IA.
• the same techniques as used in example 2 were applied, i.e. hand extrusion.
• the extra water in this formulation made the extrudate more compact.
• the dried prills disintegrated in cold water within 30 seconds.
• Powder detergent formulations were prepared using the procedure in Example 1 above, and tested with the formulations and washing conditions shown below. The quantities of the various components used are also shown below.
• a wet mix was prepared using water and the surfactant shown. This wet mix was then mixed together with the dry components and formed into a dough, which was then extruded on a Caleva model 10 extruder, using a 1 mm screen and running at a speed setting of 100. The extrudate was then spheronised on a Calvea model 120 spheroniser, running at 2700 rpm (setting 13). The resulting spheres were dried on a Strea-1 fluid-bed drier for 15 minutes, with an inlet air temperature of 70 C. The following granules were prepared:
• the L value being the reflectance valur as defined in COmmittee Internationale D'Eclarage LAB system (CIELAB)

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Organic Chemistry (AREA)
• Detergent Compositions (AREA)
• Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)

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Cited By (4)

Citations (4)

• 1990
  • 1990-10-23 GB GB909022999A patent/GB9022999D0/en active Pending
• 1991
  • 1991-10-14 EP EP91309431A patent/EP0482806A1/de not_active Ceased
  • 1991-10-22 CA CA 2053979 patent/CA2053979A1/en not_active Abandoned
  • 1991-10-23 JP JP27583291A patent/JPH04272999A/ja active Pending

Patent Citations (4)

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