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
  • C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
  • C11D17/06—Powder; Flakes; Free-flowing mixtures; Sheets
  • C11D17/065—High-density particulate detergent compositions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
  • B01J2/28—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic using special binding agents
• • 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
  • C11D11/00—Special methods for preparing compositions containing mixtures of detergents
  • C11D11/0082—Special methods for preparing compositions containing mixtures of detergents one or more of the detergent ingredients being in a liquefied state, e.g. slurry, paste or melt, and the process resulting in solid detergent particles such as granules, powders or beads
  • C11D11/0088—Special methods for preparing compositions containing mixtures of detergents one or more of the detergent ingredients being in a liquefied state, e.g. slurry, paste or melt, and the process resulting in solid detergent particles such as granules, powders or beads the liquefied ingredients being sprayed or adsorbed onto solid particles

Definitions

• the present invention relates to an improved process for granulation particularly the granulation of inorganic compounds such as light soda ash, with sodium silicate solutions , the granules so prepared and detergent compositions comprising such granules.
• Granules are granulated for the convenience of customers and users. Compared to powders, granules tend to have reduced dustiness, improved flow properties and less of a tendency for caking or separation from mixtures on standing or handling. Granules may also offer otner benefits such as rapid dissolution in water and facilitate accurate measurement of the correct dose. Granules also provide a constancy of component ratios in complex mixtures .
• Granules can be built up in a number of ways, and a large range of equipment for granulation is commercially available. In some cases all of the granule is composed of desired product while in others, inert carriers are used to facilitate granulation or to enhance granule properties, such as solubility.
• Base dry granules which are porous can be used to absorc liquids to yield free flowing products that appear dry.
• Granules of the prior art are often produced from components supplied as a fine dusty powder and this may lead to production of granules which suffer the disadvantage of being accompanied by oust.
• the presence of ⁇ ust may make the ⁇ ranuies messv to handle, difficult accurately to meter and handle, contact with the dust may cause respiratory tract irritation in some people.
• non-dusting soap granules may be formed by mixing soap dust with fatty acid and an alkaline material which saponifies the acid.
• the current invention provides a process for the preparation of granules which process comprises as a first step, agglomeration of a powdered component by agitating said component and optional additives and contacting them with a binder solution and as a second step drying the resultant agglomerate to form granules wherein said first step is carried out at a temperature below 40°C and said second step is carried out at a temperature between 30°C and 60°C and at a relative humidity of less than 50%.
• the invention provides a process for the preparation of a detergent granules which process comprises as a first step agglomeration of a powdered detergent component by agitating said component and optional additives and contacting the agitated powder with a binder solution and as a second step drying the resultant agglomerate to form granules wherein said first step is carried out at a temperature below 40°C and said second step is carried out at a temperature between 30°C and 60°C and at a relative humidity of less than 50%.
• the invention also provides granules prepared accordin ⁇ to the process of the invention.
• the term "powdered component” comprises one or more particuiate inorganic compounds of which at least 25% of the particles are smaller than 500 microns.
• inorganic compounds include, but are not limited to, sodium carbonate, sodium sulphate, zeolites, sodium tripolyphosphate, surfactants, alkali earth metal salts and alkali metal salts.
• Preferred powdered components for use in the current invention include sodium carbonate and particularly sodium carbonate in the form referred to as "light soda ash".
• the powdered component to be granulated is a dry powder comprising at least forty percent by weight of the anhydrous form of an inorganic compound which can take up water of crystallisation.
• the total powdered component contains essentially no free water and less than five percent of all forms of water. This water may be present in free form and/or as water of crystallisation, and/or held as "zeolitic" water. It is also particularly preferred that the powdered component is in a finely divided, free- flowing, lump free form.
• the properties of the granulated product formed by the process of the present invention may be adversely affected if "wet" product is used.
• the powdered component does not comprise any particles which are larger than the final desired granule size.
• a powdered component containing even small numbers of particles of size equal to or larger than the final desired granule size is undesirable as it may minimise many of the desirable benefits of the invention.
• Granulation processes usually produce granules of size which is not uniform but is distributed around a target median size.
• Granules formed by the process of the present invention are typically of median size from 0.5 to 3 mm.
• particle size means the preferred median size as determined using standard ASTM sieve measurement techniques.
• binder solution refers to any substance capable of bonding the dusty powdered component to form and maintain agglomerates thereof and to enable them to coat the agglomerating particles.
• the binder solution is compatible with the powdered component plus other additives and it also possess a "setting property" either alone or by interaction with the powdered component.
• the binder solution comprises aqueous solutions of sugars, polyacrylate polymers or neutral sodium silicate (waterglass) or water. Small amounts of surfactant material may be added to these binder solutions in order to improve their wetting properties.
• binder solutions are used at aqueous concentrations at which the liquid is viscous and "sticky".
• waterglasses are solutions of from about 25% to about 50% by weight, typically around 34% by weight. Properties of the granulated product may be adversely affected if too viscous a binder solution is used. This solution may be diluted if necessary to give a solution of viscosity which is preferably less than or equal to 250 cP at 20°C.
• sodium silicate solution is the binder solution.
• the binder solution used comprises a sodium silicate solution having a silicate to alkali weight ratio (as Si0-/Na ? 0) between 2.0 and 3.5.
• Other liquids or water soluble components can be added to this solution provided that they do not increase the viscosity of the liquid, or cause chemical changes to the sodium silicate, such a precipitation of silica.
• unacceptable additives include un-neutralised acids, salts containing free fluoride ion and, gelling agents.
• a sodium silicate solution having a low viscosity is used as binder solution.
• low viscosity sodium silicate binder solutions allow the silicate to more effectively penetrate the powders. If high viscosity sodium silicate binder solution is utilised, it is believed that less silicate is incorporated into the powders and granule properties such as solubility may be diminished.
• additives includes components such as granulising particles and dyes added to the powdered component.
• granulising particles means particles which are capable of promoting granule formulation.
• Such components are extensively described in Australian Patent No.615239 (26674/88) and include neutral and alkaline salts of alkali metal cations and organic or inorganic anions such as alkali metal orthophosphates and tripolyphosphates .
• the powder is granulated by contacting it with the binder solution, in the second step the granules formed are dried under controlled conditions.
• the process of the current invention may include other steps which are commonly practiced in granulation processes such as separation of undersized product and recycling of this product to the granulation process.
• the binder solution is broken up into fine droplets before contacting the powder.
• the binder solution can be broken up into fine droplets by any suitable method. Nozzles are commonly used in the art for reducing solutions into sprays but many other methods for forming fine droplets will be apparent to those skilled in the art.
• the fine droplets of binder solution contact the powder whilst it is being agitated.
• the agitation is such that contact of the spray with already formed granules is minimised.
• Agitation of the powder can be carried out by any suitable method but pan granulators are particularly preferred.
• the first step of the present invention is preferably carried out at a stable temperature of less than 40°C and preferably less than 30°C. Use of higher temperatures may reduce the amount of silicate absorbed and may reduce the solubility of the product in water.
• the granules are dried at low temperature and low humidity, preferably at a temperature of less than 50°C. Drying can be carried out by any suitable method but use of a vacuum dryer or fluidised bed dryer has been found to be particularly suitable. If a fluidised bed drier is used, suitably inlet air temperatures are adjusted to give a bed temperature of a maximum of 50°C (and preferably 45°C) . In practice inlet air temperatures of a maximum of 80°C, and preferably 70°C, have been found to be suitable. It is particularly preferred that drying conditions are controlled so that water evaporated from some of the drying granules does not condense other granules as this may cause caking and loss of desirable granule properties.
• composition of the agglomerates are given in Tables 1(a) and 1(b) .
• Agglomeration was performed in a small pan granulator using a hand spray to apply the sodium silicate solution.
• the pan was loaded with 200g of powder and allowed to rotate so as to produce a falling curtain of powder.
• Sodium silicate solution 200g) warmed to 40°C was sprayed onto the falling curtain of powder at the 11 o'clock position until the particles reached desired size range.
• the wet agglomerated powder was spread out on metal trays at 0.5 to 1.0 cm in depth and dried overnight in an oven at 50°C at a relative humidity of less than 50%.
• the properties of the granules are given in Table 2. Solubility was measured by the number or inversions at ten second intervals that are required to dissolve 5g of material in a 250 ml cylinder of tap water.
• Example 1 Light soda ash agglomerated in the manner of Example 1 was dried over a 48 Hour period on trays at room temperature open to the atmosphere and at a relative humidity of greater than 50%. The resulting, granules were similar in appearance to that prepared in Example 1 but contained 16.0% water and were no longer fully soluble in water.
• Example 1 Comparison of the products of Example 1 and Comparative Example I indicates that drying of the agglomerate at a relative humidity greater than 50% leads to a product of inferior solubility compared to the product of Example 1.
• Example 1 The technique described in Example 1 for agglomeration was applied to powdered blends containing Penrice Light soda ash and dried Toyobuilder zeolite A.
• the composition of the powdered detergent components used are given in Tables 4(a) and (b) .
• the technique was successful in forming granules and reducing the dusting character of zeolite A.
• the properties of the granules are given in Table 5.
• the wet agglomerate was dried under vacuum that is at a relative humidity of close to zero in the closed vessel at a temperature of 50°C after an aging period of 1 to 2 hours .
• the agglomerated powder required at least 4 hours drying under rotation before it was sufficiently dried.
• the properties of the granules formed are given in Table 7.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Wood Science & Technology (AREA)
• Detergent Compositions (AREA)

Applications Claiming Priority (3)

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• 1993
  • 1993-12-17 NZ NZ25882693A patent/NZ258826A/en unknown
  • 1993-12-17 EP EP94902553A patent/EP0675759A4/de not_active Withdrawn
  • 1993-12-17 WO PCT/AU1993/000662 patent/WO1994014529A1/en not_active Ceased
  • 1993-12-17 CA CA 2152090 patent/CA2152090A1/en not_active Abandoned

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