GB1560076A - Spray dried detergent compositions - Google Patents

Description

PATENT SPECIFICATION ( 11) 1 560 076

: ( 21) Application No 47050/75 ( 22) Filed 14 Nov 1975 ( 19) t ( 23) Complete Specification Filed 12 Nov 1976 ( 44) Complete Specification Published 30 Jan1980 / t ( 51) INT CL ' C 11 D 3/06 IZ (CIID 3/06 3/20 3/065) S ( 52) Index at Acceptance _ C 5 D 6 A 5 D 2 6 B 12 B 1 6 B 12 G 2 A 6 B 14 6 C 6 6 D 1 C 1 A 524 D 37 G 50 G 50 D 37 PD 4 VG 6 ( 72) Inventors: MICHAEL KEVIN WILLIAMS LESLIE HUGH CASSIE ( 54) SPRAY DRIED DETERGENT COMPOSITIONS ( 71) We, PROCTER & GAMBLE LIMITED, a Company organised under the laws of the United Kingdom, of Hedley House, Gosforth, Newcastle upon Tyne, NE 99 l EE, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described, in and by the following

statement: 5

The invention relates to a process for preparing spray dried detergent compositions containing sodium tripolyphosphate and low levels of organic detergents with reduced reversion of the tripolyphosphate, and to detergent compositions so prepared These detergent compositions may form the whole or part of detergent products intended for sale.

In particular, the compositions may be suitable as carrier granules for nonionic detergents 10 During the last four decades, most granular detergent compositions have been made by spray drying an aqueous slurry (the "crutcher mix") containing the active detergent, whether soap or synthetic, and some or all of the other heat insensitive solid components of the compositions Such mixes, when based, as have been usual, on soap or anionic synthetic detergents, tend to puff during the spray drying process and to form lowdensity granules 15 which are strong enough to withstand mechanical handling, packaging and storage The bulk density of these products made by various manufacturers has become much the same and users have become accustomed to using about the same volume of any product for a given purpose.

It is now being found that detergent compositions based on or containing substantial 20 proportions of organic nonionic detergents have advantages, both in cleaning certain stains from certain fabrics and in their sudsing behaviour, over those based primarily upon soap or anionic detergents Compositions of this sort are described in Netherlands laid-open Patent Applications Nos 7500903, 7504262, 7504263 and 7413522 corresponding to British Applications Nos 3629/75 (Serial No 1,489,694), 16165/74, 16166/74 and 44607/74 25 (Serial No 1,462,133), respectively.

However, crutcher mixes containing nonionic detergents are proving troublesome to spray dry Some of the problems are separation of the mix into two discrete phases, poor atomisation, density control, and, in particular, presence of fumes ("plume") in the exhaust gases from the spray dryer Although various attempts have been made to overcome these prob 30 lems, they have not been entirely successful A method of avoiding these problems is to spray the nonionic detergents, which are normally liquids or low-melting solids, onto carrier granules, on which they may be sorbed If this is to be done the carrier granules should preferably comprise as much as is possible of the rest of the composition Furthermore, they must have the desired bulk density, so that the complete product will have the density to 35 which users are accustomed Such granules are herein defined as "carrier granules" In general, allowing for some increase of density in handling before sale, the desired density of finished product is from 380 to 500 g/l, which necessitates a carrier granule density of from 250 to 500 g/l, especially from 280 to 330 g/l Copending British Patent Applications Nos.

16164/74 and 17758/75 describe methods of obtaining spray dried carrier granules of this 40 type, and of this density.

Most heavy duty detergent compositions have for many years and still do contain a considerable proportion of sodium tripolyphosphate as detergency builder, and normally this is incorporated in the slurry which is spray dried to form part or all of the detergent composition As is well known in the art, the sodium tripolyphosphate is partially hydrolysed 45 2 1,560,076 2 (reverts) to less condensed phosphates (ortho and pyro-) in the course of spray drying.

Control of the drying process limits this reversion to acceptable levels in the preparation of conventional spray dried detergent compositions based upon anionic surfactants, but the extent of reversion is found to be considerably greater when compositions such as those suitable for instance as carrier granules for nonionic surfactants and containing little or no 5 organic surfactant are spray dried in conditions such that they have bulk density in the normally desired range as denoted above.

It has now been found that the addition of a small amount of a waterinsoluble wax to the slurry before spray drying considerably reduces the degree of reversion of the tripolyphosphate during spray drying these "low active" compositions 10 It is not understood how the wax acts Either or both of two effects seem to be relevant It is found that the wax, perhaps because it inhibits phosphate hydration, makes the slurry less viscous Reduced hydration of itselt tends to reduce subsequent reversion A rather lower moisture content can thus be used to obtain similar spraying behaviour; thus less moisture has to be evaporated from the slurry, and this also leads towards less reversion 15 The invention provides a process for making a granular heat dried detergent composition which contain sodium tripolyphosphate and less than 5 % by weight of organic surfactant, comprising the steps:

(a) preparing a slurry comprising sodium tripolyphosphate, the organic surfactant if any, water, and from 0 1 to 4 % by weight of the composition of a dispersed water insoluble wax 20 having melting point in the range from 35 to 1250 C and saponification value less than 100:

and (b) spray drying the slurry to provide said granular composition.

The invention also embraces detergent compositions made by the process, and detergent products comprising such compositions 25 Normally the slurry contains from 10 to 70 %, by weight of the spray dried composition, of sodium tripolyphosphate, preferably from 35 % to 55 % It may also contain other non-heat sensitive components of the detergent composition, such as inorganic or organic detergency builders and other as more fully described below.

In this specification the term organic detergent is taken to mean one or more surface active 30 agents selected from anionic, nonionic, zwitterionic, amphoteric and cationic classes and mixtures thereof.

Anionic surface active agents can be natural or synthetic in origin; nonionic surface active agents can be either semipolar or alkylene oxide condensate types; and cationic surfactants include amine salts, quaternary ntirogen and phosphorous compounds and ternary sul 35 phonium compounds Specific examples of each of these classes of compounds are disclosed by Laughlin & Heuring in US Patent No 3929678.

Particularly preferred are the anionic detergents, especially water soluble soaps, for example, Ci 2-2 o alkali metal soaps, particularly sodium soaps of natural fats and oils, especially of coconut and tallow oils, and the alkyl benzene sulphonates having 9 to 15, preferably 10 to 40 14, carbon atoms in the alkyl chain, or a mixture of these Suitable cationic detergents include such compounds as dodecyl to octadecyl trimethyl ammonium halides, similar long chain alkyl dimethyl benzyl ammonium or alkyl pyridinium halides The amount of such detergents in the carrier granules is less than 5 % and preferably in the range from 1 to 4 %, by weight of the composition of the invention, more preferably from 1 to 2 % 45 Such waxes are hydrocarbon waxes or may be ester waxes containing a high proportion of hydrocarbon in their structure i e having saponification value less than 100, preferably less than 60 Preferably they are hydrocarbon waxes, especially microcrystalline waxes and have melting point from 65 to 115 C, especially over 100 C Suitable waxes include the petroleum derived microcrystalline petrolatum waxes, oxidised petrolatum waxes, synthetic waxes 50 made by the Fischer-Tropsch or Ziegler process, earth and peat waxes such as ozokerite, ceresin or montan waxes, and ester waxes such as beeswax, candelilla and carnauba wax.

High melting paraffin wax may also be suitable Such waxes are described in British Patent Specification No 1,492,938, corresponding to Netherlands laid-open application 7500299.

In particular petroleum based microcrystalline waxes or synthetic hydrocarbon waxes such 55 as those made by the Fischer-Tropsch process or the Ziegler process are preferred Long chain ester waxes (with low saponification values) may be used alone or mixed with the hydrocarbon waxes, but the latter alone are preferred Normally they have saponification value well below 20.

Some suitable commercially available waxes sold under Trade names are: 60 Microcrystalline wax 160/165 sold by Shell Chemicals Microcrystalline wax 185/190 sold by Shell Chemicals Microcrystalline wax 160/25 Y sold by BP Chemicals Microcrystalline wax OK 239 sold by Astor Chemicals Ltd.

Mobilwax 2305 and 2360 sold by Mobil Oil Co Ltd 65 3 1,560,076 Mobilwax Cerese sold by Mobil Oil Co Ltd.

Veba Wax SP 1044 sold by Veba Chemie AG.

Witcodur sold by Witco Chemical, of Holland They must be dispersed in the slurry and should be in powdered or flaky form, or liquid, when added to the other components during preparation of the slurry If the wax is to be added liquid to the crutcher mix its melting point should be below or only a little above that of the crutcher mix to which it is added so that it becomes dispersed before it freezes.

Quite low levels of wax are effective, as stated above, and preferred levels are in the range from 0 2 to 3 % by weight of the spray dried composition The dual function of the wax, for controlling phosphate reversion and sudsing behaviour may be taken into account in selecting 10 the optimum level in a given composition or product.

The slurry may also contain any other non-heat sensitive components of the detergent composition as stated above These include, for example, water soluble inorganic salts such as alkali metal ortho or pyrophosphates, carbonates, sulphates, chlorides, silicates, borates; organic detergency builders and salts as alkali metal polycarboxylates, aminocarboxylates, 15 citrates, tartrates and succinates; water insoluble builders such as certain alumino silicates described, for instance, in British Patent Specification No 1,429,143 Minor components which may be incorporated include soil suspending agents, e g sodium carboxymethyl cellulose and other cellulose and starch derivatives, and copolymers of maleic anhydride and methyl vinyl ether; other suds depressants such as silicones; optical brighteners, and colour 20 ing materials; and other components of detergent compositions known in the art.

The slurry must, of course, contain enough water to render it pumpable and sprayable, and normally it contains from 30 to 50 % by weight More usually, especially when densities such as those described above are required, the content is from 40 to 50 % The temperature of the slurry, when atomised at entry into the spray drying equipment, e g the spray drying tower, is 25 preferably in the range from 60 to 950 C, especially from 65 to 750 C.

The spray dried compositions generally have water content in the range from 5 to 20 %, preferably from 8 to 15 % They may be sold or used as such in cases where products with a low surfactant level are required They are very suitable for use as carrier granules for nonionic surfactants For instance from 5 to 25 % by weight of a liquid or molten nonionic 30 surfactant may be sprayed on to the granules The nonionic surfactant may be any of the many types known in the art, for instance as described by Laughlin & Heuring in US Patent 3929678 Preferred are primary and secondary branched or linear alcohols having 10 to 22 carbon atoms, condensed with from 3 to 30 molar proportions of ethylene oxide, especially alcohols with 12 to 18 carbon atoms condensed with from 4 to 15 molar proportions of 35 ethylene oxide Such materials are commercially available under Trade names "Dobanol", "Neodol" (Shell Chemicals), "Tergitol" (Union Carbide), "Synperonics" (ICI) and others.

Preferred commercial brands are Dobanol 23-6 5, Dobanol 45-7 (Shell Chemicals), Synperonic A-7, A-9, A-11 (ICI), Lial 125-7, 145-7 (Liquichemical), Tergitol 15-S-5, 15-S-7, 15-S-9 (union Carbide), and Lutensols of BASF 40 The nonionics, heated as required to melt them, may be sprayed on to a moving bed to the carrier granules in any suitable equipment such as a pan granulator, rotating drum or fluidised bed.

Alternatively the composition, whether sprayed with nonionic or not, may be blended with other particulate detergent components or compositions, such as heat sensitive components 45 e.g persalts such as sodium perborate or percarbonate; enzymes or other spray dried detergent compositions to form composite detergent products.

1,560,076 EXAMPLE I-III

Spray dried detergent compositions having the following compositions (%by weight) were prepared by spray drying:

I II III 5Sodium linear dodecyl benzene 1 4 1 4 1 4 5 sulphonate Sodium tripolyphosphate 48 0 47 0 53 0 Sodium silicate (Si O 2:Na 20 1 6:1) 16 0 16 0 17 5 10 10180 1 198 1 Sodium sulphate 18 O 18 O 198 Wax (type) 1 6 (A) 1 5 (A) 1 7 (B) Water 11 0 14 0 4 0 Minor components impurities 4 0 2 3 2 5 15 Water content of slurry 40 % 39 % 39 % Temperature as sprayed 75 C 77 C 88 C as added, assuming zero reversion Wax A was Veba SP 1044 melting point 106-111 C; Saponification value less than 10, 20 added in dry powder form to the slurry to be spray dried.

Wax B was Shell Microcrystalline Wax, melting point 85-88 C, added molten to the slurry to be spray dried.

In each case the degree of reversion of these products was less than that of a corresponding product with the wax omitted 25 Substantially similar results are obtained if the 1 4 to 1 5 % alkylbenzene sulphonate is replaced by 1 % of a sodium soap derived from an 80:20 Tallow/coconut oil blend.

Satisfactory results are obtained if the hydrocarbon waxes above are replaced by beeswax or carnauba wax (Saponification values 80 and 90 respectively), Shell Microcrystalline wax 160/165, BP Chemicals, Microcrystalline wax 160/25 Y, Astor Chemicals, Microcrystalline 30 wax OK 239, Mobilwax 2305 or 2360.

EXAMPLE IV

A detergent composition is prepared by dry mixing 60 parts by weight of the spray dried product of Example I with 25 parts by weight sodium perborate tetrahydrate in a pan granulator, and spraying on to the mixture 15 parts Dobanol 45-7 (C 14-15 primary alcohols 35 condensed with 7 molar proportions of ethylene oxide).

In this composition the Dobanol 45-7 may be replaced by an agent amount of coconut alcohol condensed with 6 molar proportions of ethylene oxide, Tergitol 15S-7 (Trade name) (Ci-i 5 secondary linear alcohols condensed with 7 molar proportions of ethylene oxide, Dobanol 23-6 5 (C 12-13 alcohols, EO 6 5), Synperonic A 7 (C 13-1 S OXO alcohols, EO 7) or Lial 40 125-7 or Lial 145-7 (C 12-15 or C 14-1 S alcohols, EO 7 respectively).

EXAMPLE V

A low sudsing detergent composition is prepared by spraying 12 parts by weight of Shell Dobanol 23-6 5 (C 12-13 primary alcohols condensed with 6 5 molar proportions of ethylene oxide), on to 88 parts of the composition of Example II, in a rotating drum mixer 45 EXAMPLE VI

Spray dried carrier granules to the following composition are prepared.

Sodium tripolyphosphate 83 % (by weight Wax (Veba SP 1044) 2 Water 15 50 The crutcher mix contains 45 % water by weight before drying.

parts by weight of the above granules are sprayed with 15 parts by weight of Dobanol 45-7 (C 14- 5 primary alcohols condensed with 7 molar proportions of ethylene oxide) to provide a detergent product with reduced reversion of the tripolyphosphate 55

Claims (1)

1. WHAT WE CLAIM IS:

   1 A process for making a granular heat dried detergent composition which contains sodium tripolyphosphate and less than 5 % by weight of organic surfactant comprising the steps:

   (a) preparing a slurry comprising sodium tripolyphosphate, water, and from O 1 to 4 % by 60 weight of the composition of a dispersed water insoluble wax having melting point in the range from 35 to 125 C and saponification value less than 100; and (b) spray drying the slurry to provide said granular composition.

   2 A process according to claim 1 wherein the slurry contains sodium tripolyphosphate in amount corresponding to form 10 % to 70 % by weight of the composition 65 A 1,560,076 3 A process according to claim 2 wherein the amount of tripolyphosphate corresponds to from 35 % to 55 %.

   4 A process according to claims 1 to 3 wherein the slurry contains from 1 % to 2 %, by weight of the composition of an anionic surfactant.

   5 A process according to claim 4 wherein said surfactant is sodium alkylbenzene sulpho 5 nate wherein the alkyl group has 10 to 14 carbon atoms.

   6 A process according to any previous claim wherein the wax has saponification value less than 60.

   7 A process according to any previous claim wherein the wax consists predominantly of petroleum derived microcrystalline wax or synthetic hydrocarbon wax and has a saponifica 10 tion value less than 20.

   8 A process according to any previous claim wherein the wax has melting point in the range 65 to 115 C.

   9 A process according to any previous claim wherein the wax has a melting point above oo 100 C 15 A process according to any previous claim wherein the wax is in powdered or flaky form when added to other components during preparation of the slurry.

   11 A process according to any previous claim wherein the slurry contains from O 2 % to 3 % of wax by weight of the composition.

   12 A process according to any previous claim wherein the slurry additionally contains 20 other non-heat sensitive components of the detergent composition.

   13 A process according to any previous claim wherein the slurry contains from 30 to % of water.

   14 A process according to claim 13 wherein the slurry contains from 40 to 50 %of water.

   15 A process according to any previous claim wherein the temperature of the crutcher 25 mix entering the spray drying equipment is from 65 C to 75 C.

   16 A process according to any previous claim wherein the spray dried composition contains from 5 to 20 % of water.

   17 A process according to claim 16 wherein the composition contains from 8 to 15 % of water 30 18 A detergent composition when prepared by a process according to any of claims 1 to 17.

   19 A detergent product comprising a detergent composition according to claim 18.

   A process for preparing a detergent product according to claim 19 which comprises spraying from 5 to 25 % by weight of the composition of a nonionic detergent on to a moving 35 bed of granules of a composition according to claim 18.

   21 A nonionic detergent containing a granular detergent composition comprising spray-dried carrier granules comprising sodium tripolyphosphate and from 0 1 to 4 % of a dispersed water insoluble wax having melting point in the range from 35 to 125 C and saponification value less than 100, having impregnated thereon from 5-25 % by weight of the 40 carrier granules of a nonionic detergent.

   22 A spray dried detergent composition according to claim 18 substantially as described in Example I.

   23 Detergent products according to claim 19 as described in Example II, III or IV.

   Agents for the Applicants, 45 CARPMAELS & RANSFORD, Chartered Patent Agents, 43 Bloomsbury Square, LONDON, WC 1 A 2 RA.

   Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1979.

   Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.