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
  • C11D13/00—Making of soap or soap solutions in general; Apparatus therefor
  • C11D13/14—Shaping
  • C11D13/20—Shaping in the form of small particles, e.g. powder or flakes
• • 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
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0073—Tablets
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/02—Anionic compounds
  • C11D1/12—Sulfonic acids or sulfuric acid esters; Salts thereof
  • C11D1/14—Sulfonic acids or sulfuric acid esters; Salts thereof derived from aliphatic hydrocarbons or mono-alcohols
  • C11D1/146—Sulfuric acid esters
• • 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
  • C11D1/00—Detergent compositions based essentially on surface-active compounds; Use of these compounds as a detergent
  • C11D1/02—Anionic compounds
  • C11D1/12—Sulfonic acids or sulfuric acid esters; Salts thereof
  • C11D1/28—Sulfonation products derived from fatty acids or their derivatives, e.g. esters, amides
• • 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
  • C11D17/0047—Detergents in the form of bars or tablets
  • C11D17/0065—Solid detergents containing builders
  • C11D17/0069—Laundry bars

Definitions

• the present invention relates to the preparation of non-soap detergent solids, especially in bar, tablet or powder form, by non-evaporative solidification of aqueous detergent pastes.
• NSD non-soap laundry detergents
• the term includes the sulphated and sulphonated anionic surfactants, non-ionic, Zwitterionic, amphoteric and semi-polar surfactants and mixtures thereof, including mixtures with minor proportions of soap.
• the term excludes soap and active mixtures containing major proportions of soap.
• the term includes those cationic surfactants, which are effective as laundry cleaning agents or fabric softeners generally used in admixture with non- ionic or amphoteric surfactants.
• soap was the only laundry surfactant of industrial significance. It was used mainly in the form of moulded bars, or sometimes as a powder. It suffers, however, from the major disadvantage that it forms an insoluble curd with alkaline earth metals, which commonly occur in water especially in "hard” water areas.
• NSD which, apart from a small proportion sold as liquid detergents, is invariably supplied as a powder formed by the evaporation of a slurry of NSD, with builders and other auxiliary detergent ingredients, in water. Evaporation is normally effected in a spray drier.
• the conventional dried NSD powder has certain disadvantages.
• the energy cost of evaporating substantial quantities of water is high, and the capital cost and relative sophistication of spray driers is prohibitive for many developing countries seeking to establish an indigenous detergent industry.
• a market persists, even in industrialised countries, for laundry surfactants in the form of bars for repeated use, or of rapidly soluble tablets which can be used as a convenient means of adding measured amounts of surfactant to the wash liquor.
• Spray drying technology is not well adapted to satisfy this demand.
• a method for the manufacture of solid NSD formulations which comprises mixing an aqueous NSD surfactant comprising a water soluble alkyl sulphate, sulphocarboxylate or sulphoester, at a concentration and temperature such that it is present as "G" phase, with builder and, optionally, other ingredients of solid laundry detergent compositions, and forming the mixture into a solid composition by non-evaporative solidification.
• an aqueous NSD surfactant comprising a water soluble alkyl sulphate, sulphocarboxylate or sulphoester
• non-evaporative solidification embraces those processes which rely primarily upon one or more of the following three phenomena to effect solidification, that is to say:
• the first of the foregoing phenomena (A) requires a "G" phase which exists only at a substantially elevated temperature and which is converted to the hydrated solid phase on cooling to ambient temperature.
• Suitable higher temperature "G” phase surfactants include sodium, potassium and tris (hydroxyethyl) ammonium alkyl sulphates, olefin sulphonates and alkyl benzene sulphonates.
• the second phenomenon (B) depends on the effects of electrolyte in raising the temperature of the "G" phase/solid phase transition boundary, and hence, effectively increasing the temperature at which the "G” phase solidifies, enabling a normally liquid crystalline surfactant composition to be obtained as the hydrated solid at ambient temperature.
• Suitable electrolytes to be used in raising the transition temperature include, for example, sodium silicate, sodium sulphate, sodium chloride, or sodium carbonate.
• the surfactant is anionic a common cation is employed to maximise the effect, thus where, as will normally be the case,the surfactant is a sodium salt, the preferred electrolyte will be a water soluble, strongly dissociable sodium salt.
• the amount of electrolyte required will depend upon the particular NSD and the extent to which the other non-evaporative solidification effects such as cooling or hydration of hydratable salts is relied upon.
• the third of the aforesaid phenomena (C) involves the abstraction of water from the "G” phase by a hydratable compound, in an amount sufficient to convert the "G" phase into a hydrated solid.
• anhydrous hydratable salt capable of exerting a dessicant action on a "G" phase surfactant
• the most convenient is anhydrous tetrasodium pyrophosphate or sodium tripolyphosphate, which are commonly included in NSD formulations as builders.
• the hydratable compound may be a partially hydrated compound.
• non-evaporative solidification does not exclude the possibility that some evaporation of moisture occurs during the process. Incidental evaporation of moisture is inevitable when aqueous materials are handled, especially at elevated temperatures. The term merely indicates that techniques are employed which do not rely on evaporation to effect solidification. It is possible within the scope of our invention to use evaporation in conjunction with the non-evaporative techniques. However, if the evaporation requires expensive drying equipment or removes a sufficiently large proportion of the moisture to increase, substantially, the energy costs, then a part of the economic benefit of the invention will have been forfeited.
• the NSD feed in the process of our invention is essentially present as a "G" phase, although it may be possible in certain circumstances to add minor proportions of the NSD in other forms, e.g. as a dilute aqueous solution, or as an anhydrous or partially hydrated solid product. In the latter case the addition of the anhydrous surfactant may contribute to the non-evaporative solidification by raising the active concentration, and may in fact constitute some or all of the hydratable compound.
• the “G” phase is a pumpable fluid which is formed over a narrow range of concentrations which range usually lies somewhere between 45% and 80% by weight of active ingredient and is characterised by a lamellar structure in which the surfactant molecules are associated to form plates of indefinite size separated by planes of water molecules.
• concentration of a surfactant in the "M 1 " phase is progressively increased a phase change occurs to give either a hydrated solid phase, or, if the temperature is sufficiently elevated, to convert the M l phase progressively to a fluid "G" phase until a viscosity minimum is reached. Further increase in the concentration of the "G” phase causes the viscosity to rise until a further phase change occurs, leading to the formation of a hydrated solid phase.
• hydrated solid phase has been used broadly to include those systems which comprise suspensions of solid or immobile gel phases in one or more viscous or gel phase to provide a more or less rigid material.
• C l ... C n are the concentrations of the individual active components and g 1 ... g n are the concentrations at which each component forms a "G" phase of minimum viscosity.
• This formula enables the concentration of the mixture corresponding to the minimum viscosity "G" phase to be estimated in a majority of cases.
• any "G" phase can be located very rapidly and easily, using standard laboratory equipment by making a test composition having an active concentration of say 75% (or, where appropriate, whatever concentration has been estimated on the basis of the foregoing formula) and placing a sample on a slide on the block of a heated stage microscope.
• the mixture is in an M 1 phase, water may be allowed to evaporate from the edges of the sample under the cover disc and any phase changes observed. If any M 2 phase or hydrated solid is present, water may be added around the edge of the cover disc and allowed to diffuse into the composition. If no "G" phase is located in this way samples may be heated progressively on the block and the operations repeated.
• the composition is pumpable at concentrations within a range of ⁇ 10%, preferably - 5%, e.g. ⁇ 2.5% of the minimum viscosity concentration. This range tends to be broader at more elevated temperatures. Compositions may be obtained, at the limits of the range in which one or more solid or gel phase is suspended in a continuous "G" phase. Such compositions may be useful according to the invention.
• the "G” phase may generally be prepared by converting a suitable precursor to the NSD in the presence of the appropriate quantity of water (e.g. an alkyl sulphuric or fatty ester sulphonic acid may be neutralised with aqueous alkali of the appropriate strength).
• Mixed NSD may be prepared either by mixing the separately prepared components, each preferably in the "G" phase, or where this is impractical, by preparing one component from its precursor in the presence of the other component as described in our British Patent 2,022,125.
• alkyl sulphates available for NSD solid formulations have been either substantially anhydrous solids and therefore difficult to mix with other ingredients, or more usually dilute solutions containing more than 60% water, which cannot be solidified at ambient temperatures except by evaporation of a major proportion of the water content.
• Non-evaporative solidification has not therefore been contemplated.
• Our invention takes advantage of a property of the more concentrated fluid "G" phase alkyl sulphates, namely their sensitivity to small changes in active or electrolyte concentration or of temperature, which enables them to be much more easily converted into hydrated solids than the more conventional detergent solutions.
• the alkyl sulphate for use according to our invention may be potassium, ammonium or lower alkyl ammonium or alkylolammonium alkyl sulphate. Particularly preferred are sodium alkyl sulphates. Sodium alkyl sulphates do not form "G" phases at ambient temperatures and are normally only available as dilute solutions less than 30% active concentration. Solid anhydrous or hydrated sodium alkyl sulphate cannot normally be melted, but tends to decompose on heating. The instability of alkyl sulphuric acids has prevented the adoption of dry neutralisation for making sodium alkyl sulphate based solid NSD formulations.
• alkyl sulphates would be attractive alternatives to alkyl benzene sulphonate for many developing countries who could prepare the former by sulphation of locally produced vegetable based feedstocks rather than imported petrochemical feedstocks required for the latter.
• sodium alkyl sulphates are prepared at temperatures of, e.g. 70°C, or even lower where mixed alkyl feedstocks were used, and the water used in the neutralisation is controlled within narrow limits to form the "G" phase, a pumpable and stable hot fluid can be obtained which is mixable with other detergent ingredients and which can be solidified by cooling to form a solid composition.
• the solid composition will normally be formed by extrusion.
• the hot alkyl sulphate mixture may be injected into a mould and cooled to form cast bars. Also, depending upon the consistency and physical form of the mixture, it may be milled to a powder and sold as such, or compacted into rapidly soluble tablets.
• the alkyl sulphate for use according to preferred embodiments of our invention is typically sodium C 8-20 linear alkyl sulphates, preferably a mixed C 10-18 alkyl sulphate. Particularly preferred is lauryl alkyl sulphate.
• Other alkyl sulphates which may be used include potassium, lithium, ammonium, monoethanolemine, diethanolamine triethanolamine and mono-, di- tri-and tetra alkylammonium salts having up to 6 carbon atoms, preferably 1 to 4 carbon atoms per cation. Salts of mixtures of the aforesaid cations and branched chain alkyl sulphates are also useful.
• alkyl sulphate may be used in admixture with any other "G" phase forming anionic NSD, or nonionic, Zwitterionic, amphoteric or semi-polar NSD or mixtures thereof.
• Cationic surfactants preferably in conjunction with non-ionic or amphoteric surfactants, may also be used.
• the alkyl sulphate constitutes at least 30% more preferably at least 50% e.g. at least 75% of the total surfactant.
• the alkyl sulphate constitute at least 80% and preferably substantially all of the anionic surfactant.
• the non-ionic surfactant is preferably present in a proportion of from 1 to 49% especially 2 to 20% e.g. 3 to 10% of the total weight of surfactant.
• the alkyl sulphate may be used in conjunction with, or be replaced by, a sulphonated fatty acid or ester such as the methyl ester of coconut fatty acid.
• the surfactant may contain an at least sparingly water-soluble, alkali metal, ammonium, alkylolamine or amine, alkylbenzene sulphonate, alkyl ether sulphate, olefin sulphonate, alkane sulphonate, alkyl phenol sulphate, alkyl phenol ether sulphate, alkylethanolamide sulphate, or alkylethanolamide ether sulphate, each having at least one alkyl or alkenyl groups with from 10 to 20 aliphatic carbon atoms.
• Said alkyl or alkenyl groups are preferably straight chain primary groups but may optionally be secondary, or branched chain groups.
• ether refers to polyoxethylene, poloxypropylene, glyceryl and mixed polyoxyethylene-oxy propylene or mixed glyceryl-oxyethylene or glyceryl-oxy propylene groups, typically containing from 1 to 20 oxyalkylene groups.
• the sulphonated or sulphated surfactant may be sodium dodecyl benzene sulphonate, potassium hexadecyl benzene sulphonate, sodium dodecyl dimethyl benzene sulphonate, ammonium lauryl monethoxy sulphate, or monoethanolamine cetyl 10 mole ethoxylate sulphate.
• anionic surfactants useful according to the present invention include fatty alkyl sulphosuccinates, fatty alkyl ether sulphosuccinates, fatty alkyl sulphosuccinamates, fatty alkyl ether sulphosuccinamates, acyl sarcosinates, acyl taurides, isethionates, and alkyl ether carboxylates.
• Anionic phosphate fatty esters may also be used.
• Preferred anionic surfactants are sodium salts.
• Other salts of commercial interest include those of potassium, lithium, ammonium, monoethanolamine, diethanolamine triethanolamine, and alkyl amines containing up to six aliphatic carbon atoms.
• the surfactants may optionally but preferably contain nonionic surfactants.
• the nonionic surfactant may preferably be, e.g. a C 10-22 ethanolamide such as coconut monoethanolamide.
• Other nonionic surfactants which may optionally be present include ethoxylated alcohols, ethoxylated carboxylic acids, ethoxylated amines, ethoxylated alkylolamides, ethoxylated alkylphenols, ethoxylated glyceryl esters, ethoxylated sorbitan esters, ethoxylated phosphate esters, and the propoxylated, or ethoxylated and propoxyTated, analogues of all the aforesaid ethoxylated nonionics, all having a C 8-22 alkyl or alkenyl group, or any other nonionic surfactant which has hitherto been incorporated in powder compositions, e.g. amine oxide
• the preferred nonionics for our invention are the less water soluble compounds, for example those ethoxylates having an HLB range of 7-18, e.g. 12-15. However, more water soluble ones may sometimes be present, usually in minor amounts. In particular, fatty alkanolamides may be useful, in minor proportions, as internal lubricants to assist in the mixing and plodding of the alkyl sulphates.
• compositions of our invention may also contain amphoteric surfactant, usually as a minor component of the active material.
• Amphoteric surfactants include betaines and sulphobetaines formed by substituting a suitable tertiary nitrogen compound having a long chain alkyl or alkenyl group with a B-acid-forming substituting agent such as chloroacetic acid.
• suitable tertiary nitrogen containing compounds include: tertiary amines having one or two long chain alkyl or alkenyl groups, optionally a benzyl group and any other substituent a short chain alkyl group; imidazoline having one or two long chain alkyl or alkenyl groups and amidoamines having one or two long chain alkyl or alkenyl groups.
• the surfactant is mixed with builders and other auxiliary detergent ingredients.
• builder is sometimes used loosely in the detergent art to include any non-surfactant whose presence in a detergent formulation enhances the cleaning effect of the surfactant. More usually, however, the term is restricted to those typical "builders”, which are primarily useful as means of preventing or ameliorating the adverse effects on washing of calcium ions, e.g. by chelation, sequestering, precipitation or absorption of the ions, and secondarily as a source of alkalinity and buffering.
• builder refers to additives which produce the foregoing effects to a substantial extent.
• phosphate and condensed phosphate salts such as sodium or potassium orthophophates, pyrophosphates, metaphosphates or tetraphosphate, as well as phosphonates such as acetodiphosphonates and amino tris methylene phosphonates. It also includes alkali metal carbonates, zeolites and other "molecular sieves" and such organic sequestrants as salts nitrilotriacetic acid, citric acid and ethylene diamine tetracetic acid.
• compositions of our invention may contain fillers which help to provide a suitable physical form of bar.
• auxiliary detergent ingredients may comprise anti redeposition agents such as sodium carboxy methyl cellulose, perfumes, dyes, optical brightening agents, hydrotopes, buffers, bleach activators, alkalis and the like.
• auxiliaries are present in proportions of. less than 10% and more usually less than 5% wt. each and less than 25%, e.g. less than 15% total.
• an NSD bar according to our invention will have the following composition:
• the filler may comprise any inert solid having suitable physical properties, e.g. sodium sulphate or talc.
• the other auxiliaries may include any or all of:- sodium carboxymethyl cellulose or other soil suspending agent; enzymes; dyestuffs; perfumes; optical brighteners; oxidising bleaches such as peroxides, perborates, percarbonates or hypochlorites; gums; starches; water soluble synthetic polymers; organic polyelectrolytes such as polyacrylic acid; and hydrotropes. Tablets for addition to washing machines may contain minor proportions of soap as foam depressants, and/or silicone anti foams.
• the properties of the "G" phase surfactant may further be modified by the inclusion of mono- di- or tri-glycerides, fatty alcohols, glycerol, glycols, polyethylene glycol or polypropylene glycol, which may help to lubricate the mixture in cases where difficulties are encountered with mixing or extrusion.
• composition of the fatty alcohol was:-
• the resulting phase was then allowed to age for a minimum period of 1/2 hour to allow it to harden off.
• the mixture were then passed 3 - 4 time through a 30 rpm. 200 lbs/ft "sunlab” plodding machine to make them plastic enough to be extruded through the same machine in the form of bars.

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Cited By (20)

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Citations (4)

• 1983
  • 1983-11-28 IN IN791/DEL/83A patent/IN160448B/en unknown
  • 1983-12-05 PH PH29924A patent/PH20175A/en unknown
  • 1983-12-06 BR BR8306706A patent/BR8306706A/pt unknown
  • 1983-12-06 AU AU22103/83A patent/AU560525B2/en not_active Ceased
  • 1983-12-07 DE DE8383307439T patent/DE3376487D1/de not_active Expired
  • 1983-12-07 GB GB08332607A patent/GB2131447B/en not_active Expired
  • 1983-12-07 KR KR1019830005793A patent/KR900004559B1/ko not_active IP Right Cessation
  • 1983-12-07 EP EP83307439A patent/EP0110731B1/de not_active Expired
  • 1983-12-07 JP JP58229974A patent/JPS59115400A/ja active Pending
  • 1983-12-07 AT AT83307439T patent/ATE33994T1/de not_active IP Right Cessation
• 1987
  • 1987-12-30 MY MY135/87A patent/MY8700135A/xx unknown

Patent Citations (4)

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