GB2184452A - Built detergent compositions - Google Patents

Abstract

A built detergent composition for washing fabrics, disks and surfaces in the form of a semi-solid gel, cream or paste contains 10% to 45% by weight of non-soap detergent active material, at least part of which is sufficient primary alcohol (C8 to C22) sulphate active to provide at least 10% by weight of the composition, from 5% to 60% by weight of detergency builder and from 0.25% to 2% by weight of alkanolamine containing 2 to 4 carbon atoms in each alkanol group. The alkanolamine improves the lather characteristics of the semi-solid gel, cream or paste without introducing a tendency to instability or a brown discolouration on storage.

Description

SPECIFICATION Detergent compositions This invention relatesto detergent compositions which are in a semi-solid form, that is to say a gel, cream or paste. Such a detergent for is already marketed in some countries. It is sufficiently solid that it cannot be poured, and it coheres together in a soft mass which can however be deformed by hand. Such a form isthus distincifrom liquids, powders and bars.

Semi-solid detergent compositions may be used forwashing fabrics, washing dishes, and/or other cleaning of surfaces. They should have certain properties to provide efficient performance of the required functions. The present invention is concerned with the lather characteristics of such compositions, containing primary alcohol sulphate asthe major detergent active.

Built detergent paste compositions which are commercially marketable will generally contain detergent active and detergent builder materials together with optional components, for example abrasives, fillers, perfumes, alkaline salts, for example silicates, and bleaching agents.

U K Patent 742567 discloses built liquid detergent compositions containing lauryl sulphate as detergent active, with triethanolammonium as cation thereof, and with a alkanolamine presentto promote homogeniety of the system.

UK Patent 583028 discloses a non-soap bar for personal washing containing cetyl sulphate as detergent active, with triethanolamine present. The purpose of including it is not stated.

In unpublished UK patent applications, the applicants describe the use of alkanolaminesto improve lather characteristics of built detergent compositions, principally in bar form.

We have nowfound that use ofalkanolaminesto improve the lather characteristics of semi-solid compositions is possible provided thatthe amountofalkanolamine is not substantially above an upperlimit.

We consider that a practical upper limit is 2% by weight of the composition. Above this two deleterious effects are observed. One is a tendency to instability. The other is a brown discolouration ofthe producton storage. Such discolouration does not destroy the effectiveness ofthe product, but makes it unattractive to users.

The stability of a semi-solid composition can be enhanced by adding a structuring agent, and it may be preferred to include a structuring agent in compositions according to this invention. Use of a structuring agentto enhance stability can achieve a stable composition with an alkanolamine contentsomewhatabove 2%, e.g. up to 3.5% or 5% by weight of the composition. However, we havefound thatthe amountof structu rant which is needed to achieve stability atthese higher alkanolamine levels also acts to harden the composition to an undesirable degree- and the tendencyto brown discolouration remains.

The present invention relates particularlyto built semi-solid detergent compositions comprising (based on the total composition)from about 10% to about 45% by weight of non-soap detergent active, and from about 5%to about 60% by weight of detergency builder. In this invention such a composition also contains alkanolamine in a quantity which is not substantially above 2% byweight.

The invention is specifically directed to semi-solid detergent compositions containing at least about 10% by weight of primary alcohol sulphate; these detergent actives have the general formula R-OSO3M where R is branched, i.e. derived from petroleum, or straight-chain alkyl group containing from 8to 22 carbon atoms. M is a cation providing water-soluble properties for the detergent active and will usually be selected from ammonium, potassium and sodium with the latter being the cation used generally. The sulphate groupwill be attached at a primary position in the alkyl group.The invention is particularly beneficial when the level of primary alcohol sulphate is above about 15% by weight ofthe composition and, more particularly,above about 20% by weight. Preferablythe level of primary alcohol sulphate in the composition is not morethan about 35% by weight.

The applicants have found the lather obtained with primary alcohol sulphate-containing compositions is labile, particularly when notably hard water is used to prepare the detergent liquor and when the composition is used at relatively low concentrations. It has been found that incorporation of an alkanolamine component in compositions containing primary alcohol sulphate improves the lather characteristics ofthe composition.

As mentioned above, the quantity ofalkanolamine should not be substantially above 2% by weight of the composition. Preferably the quantity of alkanolamine does not exceed 1.5% by weight of the composition unless a structuring agent is present. In this event about 1% aikanolamine is preferred. The amountof alkanolamine used should be at least 0.25% by weight ofthe composition. Subjectto the upper limits mentioned above, it is also preferablethatthe amount of alkanolamine component is at least 15% molar relative to the amount of primary alcohol sulphate anion present.

The alkanolamine component may be introduced into the composition as a separate additive during processing orit may be utilised as a neutralisation componentforthe primary alcohol sulphuric acid after formation. This latter latter route introduces the alkanolamine component as the cation species ofthe detergent active.

Preferably the amountofalkanolamine component is not less than about25% molar, relative to the amount of primary alchol sulphate anion. The amount of alkanolamine component may well be more than this but is preferably not more than about 60% molar relative to the amount of primary alcohol sulphate anion, sothat the alkanolamine component(s) are used in association with other usual cationic species, e.g. potassium, sodium and ammonium.

The alkanolamine,which is preferably a mono-alkanolamine, may be ofthe mono, di ortri formulation and the alkanol radical used may contain two to four carbon atoms. Monoethanolamine isthe preferred alkanolamine; diethanolamine and triethanolamine are preferred components in their classes (i.e. di- and tri-alkanolamines).

Other components Conventional structuring agents are coconut ethanolamide (CEA), gelatin, starch, and sodium carboxy methyl cellulose which also functions as an antiredeposition agent. These structuring agents may be used in combination with high levels of electrolyte. Electrolyte at a high level e.g. a high level of phosphate, is also usable as a structuring agent.

We preferto use as structing agent an aluminosilicateformed in situ during mixing of the composition, as described in our UK published patent applications.

Detergents active and builder components are well characterised in detergent bar technology. The components are described in "Surface Active Agents" by Schwartz and Perry (lnterscience 1949) and volume II by Schwartz, Perry and Berch (Interscience 1958). The detergent actives usable in the present invention in admixturewith primary alcohol sulphates may be found in the general classes ofanionic, nonionic, amphoteric, betaine and zwitterionic actives. Specific examples of detergent actives are linear alkyl benzene sulphonates, alkane sulphonates, secondary alcohol sulphates, branched alkyl benzene sulphonates, alkyl sulphates, olefin sulphonates, monocarboxylic acid salts, ethoxylated alcohols and fatty acid ester sulphonates.

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 nitrilotriacetate, sodium tartrate, trisodium carboxymethyl oxysuccinate, sodium oxydisuccinate and sodium sulphonated long-chain monocarboxylic acids.

Other ingredients, forexample silicates, e.g. sodium alkaline silicate, starch, sodium carboxymethyl cellulose, colouring materials, enzymes, fluorescers, opacifiers, germicides, perfumes, bleaching agents and fillers, for example sodium sulphate, talc, calcite and bentonite, are optionally present.

The compositions of the present invention will preferably be formulated to provide a pH in solution, when dissolved art a level of 2 grammes per litre, sufficientto ensure at least 50% of the alkanolamine component is in cationicform.

Production Asemi-solid detergent composition can be produced by adding the constituents to the waterwhich will be present in the eventual composition, and mixing.

Asuitable procedure isto heat all the water, and dissolve in it the builder, any other solid electrolyte and sodium carboxymethyl cellulose (if used) while mixing under conditions of high shear. When these components have dissolved, alkaline silicate is added,followed by detergent active and alkanolamine. After solution ofthese, aluminium sulphate is added to form aluminosilicate in situ. Finally anyfluorescerand perfume are added.

Ifaluminosilicate is notto be included, the alkaline silicate and aluminium sulphate are omitted from the above procedure. If another structurant such as coconut ethanolamide is used, it is preferably added afterthe detergent active and alkanolamine.

In the Examples which follow, all percentages are by weight of the compositions.

Example 1A Two creams were prepared, containing sodium primary (coco) alcohol sulphate (PAS) as detergent active and trisodium pyrophosphate (TSPP) as builder. The formulations, in percentages by weight, were A B PAS 25% 25% TSPP 10% 10% Na2CO3 14.8% 14.8% Ethanolamine - 1.0% Water balanceto 100% 100% The creams were prepared by heating thewaterto 60"C in a high shear mixer, and then adding thesodium carbonate and sodium pyrophosphate over about 20 minutes. When these salts had visibly dissolved the detergent active was added, followed by any ethanolamine. Mixing was continued for ten minutes afterthese dissolved.

The lathering performance of each cream was assessed in water of 20"FH (2 x 10-3 molar calcium ions), at various cream concentrations, bythefollowing procedure.

Stock solutions (1 2.5gm/litre of each of the PAS creams) were prepared in demineralised water. Foreach cream,a measured volume of the stock solution was pipetted into a 50cm3 measuring cylinder. The volume ofstocksolutionvaried depending uponthefinal product concentration required. An aliquotofcalcium hard water was dispensed into the measuring cylinder and the total volume diluted to 25 cm3 with demineralised water. Thefinal calcium hardness was 20 FH.

The stopperwasfitted into into the measuring cylinder and the latter given 50 shakes using a manual technique. The lather height (mm) was immediately measured and then assessed at 1 minute intervals overa 5 minute period. Each assessment was carried out in duplicate. The results are set out in Table I below.

Example 18 Two similarcreamswere prepared in the same way. Theirformulations, in percentages by weight, were C D PAS 31% 31% TSPP 6% 6% NaCO3 12.5% 12.5% Ethanolamine - 1.0% Water balance to 100% 100% The lathering performance was assessed as in Example 1Aaove, exceptthat an aliquot ofa stocksebum suspension was also added to the liquor in the measuring cylinder priorto dilution to 25cm3, so asto represent a soiled detergent liquor. The sebum concentration in the final liquor was 0.Sgm/litre. The results are also set out in Table 1 below.

Table I Cream Cream Lather heights (mum) concentration Time (clean systems) (gmsllitreJ (mins): 0 1 2 3 4 5 A 1.5 29 20 19 17 15 15 2.0 45 38 31 28 28 28 2.5 48 41 37 32 30 28 B 1.5 30 23 20 18 18 15 2.0 64 55 49 46 44 44 2.5 135 116 115 114 113 113 (Soiled systems) C 1.5 7 5 2 2 1 1 2.0 16 10 8 6 4 4 2.5 71 49 41 33 31 12 D 1.5 55 16 7 4 4 4 2.0 60 26 18 15 13 11 2.5 67 42 30 29 24 18 Example 2A A detergent cream Awas prepared by a similar procedure to that in Example 1A. Its formulation in percentages by weight was A Sodium cocoalcohol sulphate 25% Ethanolamine 2% Sodium tripolyphosphate 10% Sodium carbonate 5% Sodium sulphate 15% Aluminosilicate 3.5% Perfume 0.25% Water balance to 100% The aluminosilicate was formed in situ from sodium alkaline silicate and aluminium sulphate used in equivalent quantities.The sodium sulphate formed provides part of the 15% sodium sulphate in the above list.

The water was first heated to 60"C in a higher shear mixer as before. The electrolytes, i.e. tripolyphosphate, carbonate and the partofsulphate added as such,were added overabout20 minutes. When they had dissolved the alkaline silicate, detergent active, and ethanolamine were added in succession and each was mixed in until dissolved. The aluminium sulphatewasthen added, followed by the perfume. Mixing was continued for ten minutes after these had dissolved.

Example 2B A number of detergent creams were prepared by the same procedure as in Example 2A. These were tested for stability by subjecting them to a storage cycling process of 6 hours at400C followed by eighteen hours at 20-25"C overa period of 26 cycles. The criteria of stability is that the creams (a) should notshowwater separation, (b)thatthey should not become mobile and (c) cream appearance should not show signs of cracking and/or curdling.

The various compositions were as set out below. PAS denotes sodium coconut alcohol sulphate, STP denotes sodium tripolyphosphate, TSPP denotes sodium pyrophosphate, and SCMC denotes sodium carboxymethyl cellulose (which is added at the same time as the electrolytes).

B C D % PAS 23.0 23.0 23.0 %Ethanolamine - 1.0 4.0 % STP 24.5 24.5 24.5 % Na2CO3 6.0 6.0 6.0 %SCMC 1.1 1.1 1.1 % Na2SO4 2.5 2.5 2.5 % Perfume 0.25 0.25 0.25 %Water 42.3 41.3 38.3 E F G %PAS 25 25 25 %Ethanolamine 2 2 2 %Na2CO3 5 - 5 %Na2SO4 7 15 15 %Aluminosilicate 3.5 3.5 3.5 %STP 18 - %TSPP - 10 5 Water balance balance balance Creams B, C, E, F, G and also the cream A of Example 2A were stable when subjected to this testing. Cream D with 4% ethanolamine was unstable. All the creams had a satisfactory, semi-solid consistency. Only Cream D showed brown discolouration on storage.

Two compositions were also prepared having the sameformulation asAand E but with aluminosilicate structurant increased to 5%. They were undesirably hard.

Example 3 Aseries of detergent creams was prepared by a similartechniqueto that in Example 2A. Thecomposition, in percentages by weight, was Sodium coconut alcohol sulphate 25% Trisodium pyrophosphate 5% Sodium carbonate 5% Aluminosilicate structurant 3.5% Sodium sulphate Ethanolamine 13.6% Water balanceto 100% The level of ethanolamine was varied, with compensating variation in the level of sodium sulphate.

The creams weretested forstability, as in Example 2. Upto 2% ethanolaminethe creams werestable.

Abovethisthe creams were increasingly unstable.A cream with 2.5% ethanolamine and 11.1%sodium sulphate displayed instability after 15 storage cycles. A cream with 4% ethanolamine and 9.6% sodium sulphate displayed instability after only 3 storage cycles. Above 2% ethanolamine, the creams discoloured during storage.

Claims (12)

1. A built detergent composition in the form of a semi-solid gel cream or paste containing; from about 10% to about 45% by weight of non-soap detergent active material, at least part ofwhich is sufficient primary alcohol (Ca to C22) sulphate active to provide at least 10% by weight of the composition, from 5%to60% byweightofdetergencybuilderand from 0.25%to 2% by weight of alkanolamine component containing 2to 4carbon atoms in each alkanol group thereof.

2. Acomposition according to claim 1 containing at least about 15% by weight of primaryalcohol sulphate.

3. Acomposition according to claim 2 containing at least about20% byweigth of primary alcohol sulphate.

4. A composition according to any preceding claim wherein the level of primary alcohol sulphate is not morethan about 35% byweight of the composition.

5. Acomposition according to any preceding claim wherein the level ofalkanolamine component is not morethanabout 1.5% byweightofthecomposition.

6. Acomposition according to any preceding claim wherein the amount ofalkanolaminecomponentis not lessthan about 25% molar relative to the amount of primary alcohol sulphate anion.

7. Acomposition according to any preceding claim wherein theamountofalkanolamine component is not morethan about 60% molar relative to the amount of primary alcohol sulphate anion.

8. Acomposition according to any preceding claim, further including a structuring agent.

9. Acomposition according to claim 8 in which the structuring agent is aluminosilicateformed in situ during mixing of the composition.

10. A composition according to claim 9 in which the structuring agent is present in an amount of not greater than 4% by weight of the composition.

11. Acomposition according to any preceding claim wherein the alkanolamine is a mono-alkanolamine.

12. Acomposition according to any preceding claim wherein the alkanolamine is an ethanolamine.