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
  • C11D3/16—Organic compounds
  • C11D3/37—Polymers
  • C11D3/3746—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C11D3/3757—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions
  • C11D3/3765—(Co)polymerised carboxylic acids, -anhydrides, -esters in solid and liquid compositions in liquid compositions
• • 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
  • C11D17/0008—Detergent materials or soaps characterised by their shape or physical properties aqueous liquid non soap compositions
  • C11D17/003—Colloidal solutions, e.g. gels; Thixotropic solutions or pastes
• • 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
  • C11D3/02—Inorganic compounds ; Elemental compounds
  • C11D3/12—Water-insoluble compounds
  • C11D3/124—Silicon containing, e.g. silica, silex, quartz or glass beads
  • C11D3/1246—Silicates, e.g. diatomaceous earth
  • C11D3/1253—Layer silicates, e.g. talcum, kaolin, clay, bentonite, smectite, montmorillonite, hectorite or attapulgite
  • C11D3/1266—Layer silicates, e.g. talcum, kaolin, clay, bentonite, smectite, montmorillonite, hectorite or attapulgite in liquid compositions
• • 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
  • C11D3/395—Bleaching agents
  • C11D3/3956—Liquid compositions

Definitions

• This invention relates to liquid automatic dishwashing detergent compositions which are used for the purpose of cleaning soils from dishes, glasses and cookware. More particularly, it provides for such a composition containing a structuring system composed of a swellable clay, a water-soluble polymer, a source of multivalent cations together with a hypochlorite bleach and other common automatic dishwasher detergent components as well as a method for the preparation thereof.
• liquid compositions for automatic home dishwashing offers several advantages over the more predominant powdered or granular forms. These advantages include greater ease of handling in dispensing and dosing, the substantial elimination of lump formation, "caking", and dust, and improved solubility.
• liquid detergent compositions must meet certain requirements.
• the composition must be a substantially uniform mixture of ingredients to deliver the optimum combination of active components to the wash with each dose. In most current formulations, this requires that the liquid be shaken before each use to re-mix the components.
• a satisfactory product should also be substantially stable against physical separation and segregation of its active components or de-mixing.
• a high composition viscosity at a low shear rate contributes to physical stability of the liquid and protects against separation of the active components.
• Physical stability can be achieved through the use of suspending or viscosifying systems to enhance the liquid rheological properties.
• Such systems typically maintain viscosity at low shear rate under the high ionic strength conditions present in a built liquid detergent.
• the agents producing these systems must also be chemically compatible with the other components of the formula, especially chlorine bleach or hypochlorite ion at the high pH where the ion is stable.
• liquid dishwashing detergent must also be compatible with the dishwashing equipment presently available.
• Most current home dishwashing machines use detergent cups which have been designed to house powdered or granular solid detergent and deliver it to a specific wash cycle.
• the cups are not designed to contain low viscosity liquids. Consequently, any liquid for use as an automatic dishwashing composition or detergent must possess a sufficiently high viscosity to be effectively retained in the cup to avoid substantial leakage into the machine during cycles which precede the wash. Excessive leakage leads to under-dosing in the wash cycle and may negatively affect cleaning performance.
• high viscosity is desirable under storage conditions or while the material is in the detergent cup, the liquid must also be readily and conveniently dispensed from its container.
• a liquid that undergoes a viscosity decrease under the influence of applied shear such that the decrease is reversible with time after the removal of shear is preferably.
• This behaviour is termed thixotropy and is desirable for liquid dishwashing detergents. Agitation of the liquid in the container, by squeezing or shaking, will supply sufficient shear strain to initiate shear-thinning behaviour and increased liquid flow for dispensing from the container.
• Optimum flow properties allow for easily pourable liquids or fluids which maintain sufficient viscosity at higher shear rates to prevent or minimise excessive spillage.
• the liquid must also quickly regain its structure or viscosity after dispensing so it does not undergo substantial leakage from the dispenser cup in the machine.
• GB 2 164 350 describes a liquid automatic dishwashing product comprising a liquid phase which is water-containing alkali-metal tripolyphosphate, clay thickener, a chlorine bleach compound and a water-soluble polymeric carboxylic acid, for example, sodium polyacrylate.
• GB 2 176 495 describes clay thickened liquids stabilised by polyvalent metal salts of long-chain fatty acids, for example aluminium tristearate.
• hypochlorite-containing liquid automatic dishwashing detergent composition which includes a structuring system of a swellable clay, a water-soluble synthetic polymer, and a source of multivalent cations substantially minimises the problems of the art.
• This combination also gives a positive effect on the rheology of the product due, it is theorized, to interaction between the components. This positive interaction is manifested in apparent viscosity increases (at shear rates up to 450 sec ⁇ 1 and in yield point increase.
• the art details various kinds of structuring systems containing clay, polymer, or related combinations; but these are not completely satisfactory. The remarkable increase in yield point observed in this system together with superior hypochlorite stability further increases the desirability of the combination.
• Improved rheology of the composition can result in improved detergent performance through better retention in the cup and better stability against separation which provides increased reliability in dosing the proper levels of active ingredients to the machine wash cycle. Further, the improved structuring system also results in improved product dispensability.
• the present invention relates to an aqueous liquid machine dishwashing composition
• a thickening system comprising a chlorine source, an alkaline source and a builder
• the thickening system comprising a synthetic water-soluble polymer, a swellable clay and a multivalent cation, the composition having a yield point of between about 5 and 150 pascals at 25°C.
• the positive interaction which occurs between the swelling clay, the water-soluble synthetic polymer and the multivalent cation is beneficial in that it provides an enhancement of the yield point and of the low shear viscosity of the liquid.
• multivalent cations such as aluminium (III) or chromium (III) enhances the rheological properties of the autodish cleaning liquids over those structured by polymer alone, clay alone, or polymer-clay combinations. This results in increased yield point and higher viscosity at both low and high shear rates.
• the combination delivers substantially satisfactory stability against physical separation or segregation of the liquid upon storage. This provides for a more uniform product and for dosing of an optimised mixture of cleaning agents into the machine. Poor physical stability on the other hand can lead to development of a stratified liquid through the separation of a fluid layer to the top of the liquid and segregation of solids to the bottom. A physically separated liquid may be re-mixed by the end user through vigorous shaking of the bottle but this is not completely desirable.
• the use of the polymer in combination with the clay and multivalent metal ions provides for stability against separation and syneresis.
• the inventive combination also produces an enhanced yield point in autodish liquids.
• Detergent cup retention under wash conditions is higher with liquids possessing a higher yield point. Such retention is related to product cleaning performance since it governs the reliability of the detergent dose delivered to the wash cycle in the machine.
• the present invention allows for desirable yield points with lower levels of insoluble clay minerals to be used in automatic dishwashing liquid detergents. Liquids structured with clay alone can develop a high yield point if sufficient quantities of clay are used. However, the presence of insoluble clay minerals or silica negatively affects glass spotting and filming performance.
• the combination as described in the present invention has an advantage over a composition structured with synthetic polymers alone in that an otherwise unattainable yield point is achieved. Liquids containing for example, polyacrylate as the only structuring agent do not appear to possess a yield point and consequently, suffer from poor cup retention.
• the combination described in this invention constitutes an efficient and cost-effective structuring system.
• the colour of swelling clays available in bulk quantities ranges from off-white to shades of brown or yellow.
• the whiter clays are preferred for use in a consumer product where colour is an important factor.
• the high purity white clays tend to be significantly more expensive than the off-colour varieties.
• the use of the combined clay/polymer/multivalent ion structuring system allows for lower quantities of clay to be used.
• a lower quantity of a pure white clay can be used at a moderate cost savings because the polymer/multivalent ion combination is less expensive than the clay.
• a less expensive off-colour clay may be tolerated because in combination with the polymer and multivalent ions lower concentrations of clay are required.
• the structuring system of this invention can be tailored to develop an optimum fluid rheology in terms of low shear rate attributes (physical stability and cup retention) and moderate shear rate flow behaviour during dispensing. Because the structuring system is composed of more than one part, the clay content can be modified independently of the polymer content or the cation concentration. Thus, the rheology of the liquid can be optimised more easily than a one or two part system.
• the liquid automatic dishwashing detergent of this invention is in the form of a slurry-like paste.
• This thixotropic material possesses a yield point as determined with a rotational viscometer (Haake Rotovisco RV100) with a cup and bob sensing configuration. Measurements are made with a linearly increasing shear rate of 15 sec ⁇ 1/min. Yield point is practically measured herein as the stress level at which the stress vs. shear rate curve initially deviates from linearity.
• the liquid has a yield point of about 5 to 150 pascals or even higher at 25°C. Preferably 30 to 100 and most preferably about 40 to 80 pascals at 25°C for ease in processing and dispensing from the container.
• the liquid cleaning agent should also possess a viscosity of about 0.1 to 15 pascal seconds at 25°C and 21 s ⁇ 1, preferably 1 to 9 pascal seconds and, most preferably 1.5 to 5, to facilitate dispensing and processing.
• the swelling clay component of the structuring system may be a clay mineral of the smectite type.
• the clay can be naturally occurring or synthetic and of the dioctahedral or trioctahedral type.
• Examples of the natural clays that may be used in this invention are montmorillonites, hectorites, nontronites, beidillites, saponites, and sauconites. Materials of this type are available under the names of Gelwhite GP and Thixagel (trade names of Southern Clay). Synthetic swelling clays such as Laponite (trade name of Laporte Industries) may also be used.
• the smectite type clay should preferably be in an alkali or alkaline earth metal exchange form and should be white or most preferably of a high white purity.
• Peptizing agents such as hexametaphosphate, pyrophosphate, or other polyelectrolytes known to the art may be used.
• the clay may be present at about 0.1 to 15%, preferably about 1 to 5%, and most preferably about 1 to 4% by weight of the final products.
• the use of excessive amounts of clay within the formulas which contain high levels of other solids can lead to viscosities considerably above the preferred range.
• the polymer used should be of a synthetic type and be water-soluble.
• the polymer should also be anionic.
• Examples of applicable polymers are water-soluble carboxylic polymers such as polyacrylic acid and its salts, polymethacrylic acid and its salts, copolymers of acrylic acids or methacrylic acids with co-monomers such as alkyl acrylates, alkyl methacrylates, and polymaleic acids and their salts.
• the preferred salts are alkali-metal salts such as, for example, sodium.
• These polymers may have a weight average molecular weight of from 60,000 to about 2,000,000 or higher with a molecular weight of from 60,000 to 500,000 preferred, and 100,000 to 300,000 most preferred.
• the polymers may be used in the acid or the neutralised form.
• the polymers should be of a hypochlorite stable type with polyacrylate and polymethacrylate being most preferred.
• the polymer should be of a purity such that it contains a minimum of unsaturated monomers, chemically reactive initiators, terminators, or surfactants present all of which hasten the rate of hypochlorite decomposition.
• the polymer may be present in the formula at about 0.05 to 8% by weight, from 1 to 4% being preferred, and from about 1 to 3% by weight being most preferred.
• the use of excessively high polymer concentrations can lead to gumminess and extremely high viscosities. Excessively high polymer molecular weights can product liquids with a very stringy and pituitous flow behaviour.
• a source of soluble or solubilised multivalent cations is the third component of the viscosifying system, preferably employing inorganic chlorides, sulphates and the like.
• Trivalent cations (M3+) such as aluminium (III), chromium (III), and iron (III) may be employed as well as divalent cations (M2+) or cations with higher valencies.
• the source of ions should be present in the formula at about 0.01 to 3% by weight with 0.01 to 2% more preferred and 0.01 to 1.0% the most preferred.
• metal ions include: Group No Example IIA barium IVA titanium, zirconium VIA chromium VIIA manganese VIIIA iron, cobalt, nickel IB copper IIB zinc IIIB aluminium IVB tin
• An alkali-metal condensed phosphate may be present in the formula as a water hardness sequestering agent or builder.
• Tripolyphosphate is the preferred sequestrant although pyrophosphate, hexametaphosphate, or other condensed phosphates may be used.
• the sequestrant may be present in the formula from about 0.1 to 35% with 15 to 25% by weight being more preferred.
• Use of the sequestrant, such as sodium tripolyphosphate, in excess of its solubility limit within the formula requires that the solid be present as fine particles which are suspended by the structuring system. The presence of solids will affect the viscosity of the liquid and may modify the range of the structurants needed to deliver the proper rheology.
• inorganic builders which may be used are sodium and potassium salts of polyphosphate, orthophosphate, carbonate, bicarbonate, sesquicarbonate and borate.
• Organic detergent builders can also be used in the present invention. They are generally sodium and potassium salts of the following: citrate, nitrolotriacetates, phytates, polyphosphates, oxydisuccinates, oxydiacatates, carboxymethyloxy succinates, tetracarboxylate, starch and oxidised heteropolymeric polysaccharides.
• Sodium citrate is an especially preferred builder.
• Water-insoluble aluminosilicate ion-exchange materials may be used as alternative builders (e.g. GB 1 473 201 and 1 473 202 - Henkel). These are crystalline or amorphous materials of general formula (Cat 2/n 0) x. Al203(SiO2)y. ZH20 wherein Cat is cation having a valency n that is exchangeable with Calcium (e.g. Na+ or K+); x is a number from 0.7 to 1.5; y is a number from 1.3-4; and z is such that the bound water content is from 1% to 28% by weight.
• Cat is cation having a valency n that is exchangeable with Calcium (e.g. Na+ or K+)
• x is a number from 0.7 to 1.5
• y is a number from 1.3-4
• z is such that the bound water content is from 1% to 28% by weight.
• Preferred is the commercially available product Zeolite type A- Na
• An alkali metal carbonate may be used as an alkaline buffering agent from about 0.1 to 30% or more preferably from 5 to 15% by weight.
• Alkali metal silicates with an Si02:Na20 weight ratio of about 1.0 to 3.25 may be used as alkaline sources and as anticorrosion agents to protect metal and china surfaces against the harshly alkaline environments present in the wash.
• the silicate may be used in the form of an aqueous liquor or a solid, preferably present in the formula at about 0.1 to 25% by weight, and more preferably from 5 to 10%.
• An alkali metal hydroxide may be used as an alkaline source and as a means to boost the pH of the liquid detergent to a pH of 10 to 13 to stabilise the hypochlorite.
• a preferable pH range is 11 to 12.5 to optimise hypochlorite stability and consumer safety.
• Sodium hydroxide in the form of an aqueous liquor or as a solid will be used in the formula to achieve the above pH range, typically about 1 to 2.5% by weight, or higher, depending on the other components.
• the surfactants optionally used in this invention may be those normally used in machine dishwashing products provided they are sufficiently stable with hypochlorite. These surfactants should be of the low-foaming type as foam interferes with the dishwasher cleaning action. While this invention is not limited to any particular surfactant or type or surfactant, the surfactant should possess stability against degradation by hypochlorite.
• the preferred nonionics are condensates of 8 to 12 carbon linear alcohols with polymers of ethylene oxide or propylene oxide in either a random copolymer or as block polymers provided sufficient hypochlorite stability is introduced by appropriate means, such as for example, end capping. Hypochlorite stability is enhanced in surfactants of this type which contain relatively higher propylene oxide to ethylene oxide ratios. Surfactants of these types are present in this invention at about 0.1 to 25% by weight, with from 0.1 to 5% preferred and about 0.1 to 3% most preferred.
• Highly foaming surfactants are preferably excluded or are used in only minimal amounts, or if desired with effective hypochlorite stable defoaming agents.
• Low foaming anionic surfactants are preferred for this invention, especially in combination with effective defoamers, in that these surfactants are shown to be more stable towards hypochlorite.
• Anionic surfactants may be present in the composition of this invention from about 0.1 to 25% by weight, with from 0.1 to 3% preferred.
• surfactants examples include alkyl diphenyloxide sulphonates; alkyl sulphonates; alkyl napthalene sulphonates; and nonionic surfactants as described above in which a sodium alkylene carboxylate moiety had been linked to the terminal hydroxyl group(s) through an ether bond.
• Defoaming of the wash may be accomplished by the presence of any of a number of commercially available defoaming agents. These agents may be of the general type of slightly soluble alkyl carboxylates, alkyl phosphates, hydrophobic silicas, silicone defoamers, or many others. In addition to being an effective defoamer the species must be stable to hypochlorite.
• the defoamer will optionally be present in the composition from about 0.1 to 5% by weight, more preferably from 0.1 to 1%, and most preferably from about 0.1 to 0.5%.
• Stable chlorine bleaches known to the art such as alkali metal hypochlorites, chlorine containing organics which yield available chlorine or the like may be present in the formula as agents for removing tea, coffee and other food stains from cups, dishes, flatware, etc.
• the bleach source may be present in the mixture at about 0.1 to 10% by weight with the most preferred range being about 0.1 to 2%. Common bleaching agents which are well known in the art may be used. For substantially effective compositions, about 0.1 to about 2% weight of available chlorine is desirable.
• Typical stable colourants or pigments such as TiO2, fragrances and other adjuvants may be employed as desired with the provision that they must be adjusted to achieve appropriate viscosity and stablility.
• the process of this invention incorporates several factors essential to the production of liquids possessing the proper rheological properties. These factors include the order of mixing, the characteristics of the raw materials and the processing temperatures.
• Preferred orders of addition effectively combine the structuring components, clay, polyacrylate and multivalent cations in a low electrolyte concentration aqueous solution. This forms a thickening matrix in the absence of excess electrolyte.
• One portion of the sodium tripolyphosphate, as well as the MSAP premix, surfactant solution, sodium hydroxide present in the polymer premix, colourants, etc. may be present during the admixing of the structuring components.
• the bulk of the solution electrolyte however is added after the structuring components.
• the electrolyte is contributed by the alkali metal silicate, the alkali metal carbonate, and the remainder of the tripolyphosphate. Hypochlorite bleach is typically added last after cooling of the mixture.
• the order of addition and approximate temperature ranges are illustrated in the following list: Component Preferred Temp. °C Water 15-25 Clay 15-25 40-50 Sodium Tripolyphosphate 50-60 Polymer Premix1 50-60 Multivalent Cation 50-60 Sodium Silicate (2.4 Ratio) 50-60 Sodium Carbonate 50-60 Defoamer 50-60 Surfactant 50-60 Sodium Tripolyphosphate 50-60 Sodium Hypochlorite 30-30 1
• the polymer premix is prepared by combining sodium hydroxide 50% liquor with a polymer solution.
• the structuring components are the clay, the polymer and the multivalent cation source. Very low electrolyte concentrations are preferred to hasten the rate and extent of clay swelling which is essential for the development of the structuring system.
• a partial flocculation of the clay occurs upon the dissolution of the STP. The flocculates are desirable to increase the adsorptive interaction of the polymer with the clay particles. Addition of cations should occur prior to the addition of the carbonate and silicate to increase the effectiveness of the multivalent metal ion/clay/polymer interactions.
• the sodium tripolyphosphate (STP) is split into two separate additions. This method of addition offers a significant enhancement of the final batch rheology compared to a single addition.
• Raw material selection plays an important role in determining the ease of mixing and the rheological quality and smoothness of the final product.
• Tripolyphosphate characteristics are critical to the process.
• the STP used in the process is a commercially available material which provides for the proper granulation type, anhydrous crystalline phase content and prehydration conditions.
• the sodium tripolyphosphate of choice is a medium to light density granular anhydrous form with a preferred unpacked bulk density of about 0.45 to 0.85 g/cc, with a more preferred range of 0.50 to 0.8, and the most preferred density of from 0.50 to 0.7.
• Preferred levels of prehydration are from 0.1 to 6.0 wt.% water, with the more preferred range being from 0.1 to 2.0, and the most preferred from 0.1 to 1.4.
• the preferred anhydrous sodium tripolyphosphate crystalline phase Type I content is from 20% to 60 wt.% with the more preferred content from 25% to 55%, with the most preferred range of from 30% to 50%.
• the STP selection plays a major role in controlling the grittiness of the final liquid and the mixing time involved in processing.
• the clay must be both easily dispersed in cold water and quickly swelled in warmer water. A number of swelling clays posses both attributes. Peptising agents may be useful in both of these processing steps.
• the temperature parameters outlined above are also criticalities of the process. Control of the mixing temperature within about +/- 10°C of those described is essential to the success of the process. The maintenance of low (15-25°C) water temperature eases the dispersion of the clay. Raising the temperature to 40-50°C increases the swelling rate of the clay, thus allowing for shorter mixing times. Addition of the STP at this temperature allows for rapid hydration of that salt and for the exothermic nature of the reaction. The exotherm causes the temperature of the mixture to rise about 5°C. About 65°C is a maximum temperature and a criticality of the process, substantially exceeding this temperature has a deleterious effect on the viscosity and rheology of the final product. The mixture should be cooled before hypochlorite addition to minimise degradation.
• the cooling rate has a major influence on the rheological quality of the final product. Too slow a rate (less than about 0.5°C/min.) results in a final product that is too low in viscosity.
• the preferred temperature for hypochlorite addition is about 30°C or lower.
• anhydrous tripolyphosphate which forces the formation of finely dispersed tripoly­phosphate hexahydrate crystals early in the mixing process is beneficial.
• the use of the anhydrous tripolyphosphate at the end of the batch requires that the phosphate dissolve and recrystallise onto those finely divided nuclei produced initially.
• the resulting automatic dishwashing detergent is a thixotropic opaque liquid which is offwhite colour.
• the consistency is of a smooth, creamy liquid which possesses a yield point.
• the yield points and viscosity data were collected using a Haake Rotovisco RV100. The measurements were taken at a uniformly increasing rate of about 15 s ⁇ ­1/min The formulations were tested 24 hours after mixing, and these results are shown for the three formu­lations in Table 2.
• Table 2 Rheological Comparison of the Three Formulations Viscosity at 25°C as measured in Pascal seconds (1) (2) (3) 5 s ⁇ 1 5.4 8.3 9.2 21 s ⁇ 1 1.8 2.7 2.8 Yield Point at 25° as measured in Pascals (1) (2) (3) 2.2 15.6 29.0
• the distilled water (113.32g) was placed in a 1 litre stainless steel beaker at 20°C.
• Eight grams of Gelwhite GP was sifted slowly into the water while agitation and shear were supplied by a mechanical stirrer to form a slurry. After the slurry was uniform and smooth, it was heated to 45°C with continued stirring.
• 40g of granular anhydrous sodium tripolyphosphate was added into the slurry and, after the mixture was uniform, the temperature was increased to 55°C.
• 32g of Acrysol A-3 which was in the form of a 25% solids (solute) solution was premixed with 9.6g of a 50 wt% sodium hydroxide solution to neutralise the polymer and adjunct the pH.
• the neutralised alkaline polymer premix was then added to the slurry. After 5 minutes of stirring, 0.8g of aluminium sulphate, eighteen hydrate was added to the mixture and stirred for 10 minutes. The remaining ingredients were added in the order listed in Table 3, with 5-10 minutes between each addition.
• Into the slurry was added 71.12g of 47.1 wt% sodium silicate solution with a SiO2/Na20 ratio of 2.4 to 1. Next was added 24g of sodium carbonate, followed by addition of 24.64g of a 2.6 wt% premix of stearyl acid phosphate in water. Next, 3.2g of Dowfax 2A-1 surfactant (45% actives) was added.
• the resulting automatic dishwashing detergent is a thixotropic opaque liquid which is off white in colour and which possesses a yield point.
• the yield points and viscosity data were collected using a Haake Rotovisco RV100. The measurements were taken at a uniformly increasing rate of about 15s ⁇ 1/min. The formulations were tested 24 hours after mixing and the results are shown in Table 4.
• Table 4 Rheological Comparison of the Two Formulations Viscosity at 25°C as Measured in Pascal Seconds (4) (5) 5 s ⁇ 1 11.4 2.3 21 s ⁇ 1 2.7 1.2 Yield Point at 25°C as measured in Pascals (4) (5) 50 19
• formulation (4) is similar to formulation (3) in Example 1 yet the yield point in formulation (4) is much higher. This reproducible difference is believed to be attributable to changes made in the process and in the order of mixing.
• Table 5 shows the effect of several metal ions on the yield point of an automatic dishwashing liquid according to the invention as compared to a control without metal salt. This control was run independently yet a close correlation can be seen with formulation (2) of Example I. It can be observed that the addition of these metal cations at a level of 0.2 wt% of the salt enhances viscosity and yield point.
• the composition of each formulation is identical to formulation 3 from Example I above except that the specified metal salts are substituted for aluminium sulphate.
• enhancement factor is used to describe the increase in the yeild point (YP) which occurs when the combination of the invention is used as a structurant.
• the factor is calculated by dividing the yield point of the sample containing the combination of the three components by the sum of the yield points of samples which contain clay, polymer and multivalent metal cation individually.
• the YP of the inventive compositions containing the metal cations polymer/clay combination is measured and reported above.
• the YP of the individual components is reported below. Yield Points of individual components WT% (1) (2) (3) Clay 2.0 0 0 Polymer (Acrysol A-3) 0 2.0 0 Metal Cation 0 0 0.2 Yield Point (Pascals) 2.2 3.5 0.0
• Table 6 demonstrates the effect of changing metal salt concentration. Increasing salt content with its concomitant increasing cation content increases the yield point and viscosity for the composition shown. This composition is similar to formulation 3 from Example 1, with the exception of the salt content and water content being varied to achieve 100%. These samples were tested one week after they were mixed. The enhancement factors are calculated in the same way as for Table 5.
• the presence of multivalent metal cations in the autodish detergents of the invention improves hypochlorite stability relative to clay-polymer alone.
• the rate of hypochlorite degradation as a function of time is decreased when the metal ions are present.
• Hypochlorite stability of the samples is measured by monitoring the concentration of hypochlorite by titration. This is reported as % available chlorine.
• Table 7 shows the available chlorine content of samples stored at various temperatures. Formulations shown in this table contain clay-structuring (1), clay-polymer structuring (2), and clay-polymer-aluminium (III) structuring (3), and are identical to the formulations in Example 1.
• Clay-­structured autodishwashing liquids are generally considered to be hypochlorite stable.
• a batch of autodish liquid including the above listed components was prepared using a Versamix (from Charles Ross and Sons, Inc.) of approximately 2 gallon capacity fitted with an anchor blade and a disperser blade.
• a polymer premix was prepared by adding 192 g of sodium hydroxide 50% liquor to 640 g of Acrysol A-3 25% solution with agitation. The temperature of this premix was kept below 70°C to minimise discoloration. This mixture was intentionally overneutralized to have a pH of about 12.9. The premix, thus prepared, can be added to the slurry batch while either hot or cold.
• a 2.6wt% defoamer premix was prepared by homogenizing stearyl acid phosphate in water at 25°C.
• the stearyl acid phosphate used was "High mono grade" obtained from Occidental Chemical Company and was a mixture of monostearyl and distearyl acid phosphates.
• the defoamer premix may be prepared at 70°C using conventional high speed agitation.
• the freshly prepared polymer premix was than added to the slurry while still hot, and mixed for 10 minutes. 160 g of aluminium sulphate. l8H2O was then added to the slurry as crystalline powder while avoiding lump formation and mixed for about 10 minutes.
• the silicate, carbonate, defoamer premix and surfactant were than added stepwise with mixing to the slurry.
• 1422.4g of a 47 wt% solids solution of 2.4 ratio (2.4:1 SiO2:Na2O) sodium silicate (from PPG) was added.
• 480g of sodium carbonate, grade 100 medium density ash (from Monsanto Company) was added.
• 616g of the defoamer premix was added.
• 640g of Dowfax 2A-1 surfactant was added as a 45 wt% solution (received from Dow). Approximately 10 minutes between additions was allowed to ensure sufficient mixing.
• the temperature of the mixture was maintained between 50-55°C. Addition of the second 800 g portion of sodium tripolyphosphate affords an exotherm of about 4°C. The speed of the disperser blade is decreased to approximately 200 rpm once addition of the second portion of STP is complete, to avoid overshearing the liquid. The mixture was stirred until the STP granules were substantially hydrated (approximately 45-60 minutes). The mixture was then cooled with agitation to 30°C. These conditions produce a viscosity increase after about 20 minutes.

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• 1988
  • 1988-06-09 ES ES88305256T patent/ES2023255B3/es not_active Expired - Lifetime
  • 1988-06-09 DE DE8888305256T patent/DE3863131D1/de not_active Expired - Fee Related
  • 1988-06-09 EP EP88305256A patent/EP0295093B1/de not_active Expired - Lifetime
  • 1988-06-09 CA CA000569046A patent/CA1315640C/en not_active Expired - Fee Related
  • 1988-06-10 JP JP63143449A patent/JPS644699A/ja active Pending
  • 1988-06-10 AU AU17619/88A patent/AU596310B2/en not_active Ceased
  • 1988-06-10 ZA ZA884170A patent/ZA884170B/xx unknown
  • 1988-06-13 BR BR8802888A patent/BR8802888A/pt not_active Application Discontinuation

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