GB2206601A

GB2206601A - Automatic dishwashing detergent powder

Info

Publication number: GB2206601A
Application number: GB08813094A
Authority: GB
Inventors: Fahim Uddin Ahmed; Michael Armand Camara; James A Kaeser; Charles Edward Buck; Jnr James Frank Cush
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1987-06-05
Filing date: 1988-06-03
Publication date: 1989-01-11
Anticipated expiration: 2008-06-03
Also published as: AU614287B2; DK301988A; FR2616156B1; GB8813094D0; DK301988D0; BE1003812A5; DE3818660A1; CA1316788C; SE8802056D0; IT8848051A0; IT1219635B; GB2206601B; ES2009932A6; SE8802056L; CH678190A5; AU1740088A; FR2616156A1

Description

1 2206601 "AUTOMATIC DISHWASHING DETERGENT POWDEC The present invention

relates to an improved 5 automatic dishwashing detergent powder with superior performance solubility, pourability,, handling and storage characteristics and a method for making and using the same.

In general automatic dishwashing detergent powders io contain water soluble builder salt, watersoluble sili cate, bleach, preferably a water-soluble chlorine bleaching agenti and water-soluble detergent which is usually an organic, low-foaming (i.e. low "sudsing") non-ionic. For best cleaning efficiency and anti corrosion effects, the compositions are usually formu lated with alkaline salts (i.e. sodium and potassium).

In the normal environment in the dishwashing machine, the automatic dishwashing compositions generally yield a pH in the range of about 9. 0 to 12. 0 and more generally about 9.5 to 11.5. The alkaline builder salts which have been used are both of the inorganic type (e.g. pyrophosphates; carbonates, silicates and so forth) and of the organic type e.g. aminocarboxylates such as trisodium. nitrilotriacetate, tetrasodium ethylene diamine tetra-acetate# sodium citratei sodium itaconate, sodium polymaleate, sodium inter polymaleates, such as maleic-acrylic (or vinyl) interpolymers, sodium oxydisuccinate and so forth.

The builder generally functions to increase the 30 cleaning action of the composition by supplying alkalinity and also by removing (i.e. "sequestering") ions which affect the action and efficiency of the organic detergent.

2 The silicates which have been used are those wherein the Na20:S'02 ratio varies from 2:1 to 1:4 and more generally from about 1:1 to about 1:3.4, typically 1:1 to 1:2A or 1:1 to 1:2.

The bleach employed is generally a chlorineyielding agent and has been used in varying amounts but generally to give available chlorine levels. of from about 0.3% to about 10% and. more often, levels of about 1 % to 5%. Typical bleaches are the inorganic types such as sodium, lithium and calcium hypochlorite, and chlorinated trisodium phosphate, as well as the organic f orms such as the di- and tri-chlorocyanuric acids and their alkali metal (e.g. sodium and potassium) salts, N-chloracetyl urea and 1 3-dichloro- 5,5-dimethylhydantion.

The nonionic detergents in common usage have been any of the conventional hydrophobe moieties (e.g. C8 to C20 alcohols, phenols,, amides or acids) reacted with ethylene oxide (or mixtures with other oxyalkylating agents such as propylene oxide or butylene oxide). Typical nonionics used have been n-dodecanol with 10 moles of ethylene oxide; tetradecyl alcoholhexadecyl alcohol (1:1 weight ratio) with 5, 10, 15 or 20 moles of ethylene oxide; polyoxypropylenes condensed (i.e. terminated) with oxyethylene groups and having the general formula HO(C2H40)x(C3H60)y (C2H40)zH wherein y = 5 to 100 and typically 10 or 15 and x and z may be from about 5 to several hundred e.g. 10, 20, 40, 50, etc. Among the latter type of nonionics have been those where the oxyethylene component comprises from about 15% to 90% on a weight basis of the non-ionic. Types of non-ionic detergent disclosed as generally useful in automatic dishwashing compositions can be found in U. S.

3 P Patents 3314891, 33592070. 2677700, 297 9528 1, 3036118, 3382176, 4115308 and 4411810. It has been known and generally described that non-ionic surfactants even though a preferred class of detergents because of their low-foam character i stic s. are not, generally, considered "bleach- stable" detergents and where the latter is of importance use of anionic surfactant. albeit higher foamers, has been reported. A discussion of this problem and illustrations of this approach can be found in U.S. Patents 4116849. 5005027 and 4235732.

Automatic dishwashing detergents have been provided in two basic forms, as powders and as "liquids" (or semi-liquids or pastes). The powders represent the "first generation". They are simple to formulate, easy to dispense from machines which have, in the main,, been designed to handle powders and not liquids; and because of the presence of the formulation flactives" in solid state, (and usually the components comprise separate and discrete particles), there is a minimum of interaction among the composition ingredients. "Liquids", the so-called "second generation" of products in this area, on the other hand, are more convenient to dispense from the package; also they are generally more soluble in water and therefore have less tendency to remain and/or leave residues in the machine dispenser cup. Phase separation leading to decreased homogeneity and an exacerbation of component interaction are among some of the disadvantages of the liquid system. Some of the U.S. Patents mentioned earlier are specifically directed to "liquid" systems.

V.e present invention rela tes to an improved automatic dishwashing detergent in powder form which is highly efficacious, has superior stability, is phase 4 stable and homogeneous and not withstanding its powder characteristic has many of the advantages of the liquid systems i.e. dispensibility, pourability and solubility without, however, the problems and disadvantages often attending the use of liquid automatic dishwashing compositions.

The compositions of this invention comprise builder salt, generally alkaline builder salt, alkalimetal silicate, non-ionic surfactant and as a preferred optional ingredient, bleaching agent. The product is characterized by a base bead of builder salt having absorbed thereon the nonionic surfactant, said bead being admixed with the silicate and bleach (where used). Where other optional materials are used they, too, are conveniently post blended with the base beads.

These materials may be alkali salts including builder salts,anti-oxidants, dyes. pigments, fragrances, anti foamers, fillers. sequestering agents, soil suspending agents# drainage improvers and the like.

The present invention relates to an improved and superior automatic dishwashing detergent composition in powder form which is free flowing. non-caking, homo geneous, highly soluble and very lowi if not entirely free of insolubles and residue when in usei and methods for making and using such compositions.

The outstanding automatic dishwashing compositions which are provided are powders and comprise a base material on which is absorbed or "loaded" a detergent,, and in admixture therewith an alkaline silicate and any other desired components. of particular value is a bleaching agent and alkaline reacting compounds such as alkali carbonates, bicarbonates, borates, hydroxides and so forth.

The base material which is the carrier for the surfactant is a spraydried phosphate composition which also contains a small amount of a polymeric substance.

The spray-dried base is generally characterized as _5 a "base bead" although it may not necessarily be a bead in the usual geometric f orm. The absorbent base material is comprised of a major portion of inorganic salts and generally and preferably phosphate material.

Suitable phosphates include trisodium phosphate, sodium tripolyphosphate, monobasic sodium phosphate,, dibasic sodium phosphate, dibasic sodium pyrophosphate, tetra sodium pyrophosphate, sodium hexametaphosphate and the like. The corresponding potassium salts along with mixtures of sodium and potassium salts are useful. It may be desirable to add other salts to the phosphate such as the alkali metal carbonatest bicarbonates, borates and silicates. The alkaline earth salts (e.g. calcium, magnesiumi etc.) of the non-phosphate inorganics may be used if desired and/or indicated. In general, the base "bead" is prepared by spray-drying a slurry of the phosphate-containing composition. The processing of detergent free phosphate slurries and spray-drying them to form base beads is described in U.S. Patent 4414129 to David Joshi.

The base material will generally comprise from about 50 to 95% alkali-metal polyphosphate. on an anhydrous basis. the base may comprise from about 50% to 99% of inorganic salts and again, preferably alkali metal polyphosphate. Minor amounts of moisture are almost invariably present and the water content may vary from a few or less percent (e.g. 0.5%. 1%r 2%j 3%) to 20% and more but more generally f rom about 5% to 15%. typically 6%, 8%, 10% and 12%.

6 - other alkaline saltsi particularly sodium carbonate, sodium tetraborate and sodium silicate may be admixed with the phosphate in the crutcher before spray-drying. Generally these materials are used in less than major amounts, generally from very small amounts e.g. 1%. 2% or 5%,, up to larger quantities, typically 10%, 15%j 20%r 30%j 35% or 40%. Where silicate is used in the crutcher mix 'it is usually one of lesser alkalinity e.g. Na20:S'02 ratio of about 1:1A to 1:3A typically 1:2A.

A second preferred component of the base bead is a water-soluble polymeric material such as sodium polyacrylate, which.is the most preferred polymer salt. Other water-soluble polymers (at least soluble in such salt form) as poly (hydroxy) acrylates, copolymers and inter polymers of acrylic acid with other copolymerizable monomers (usuallyo, P- olefinicially unsaturated) such as vinyl pyrrolidone, vinyl acetate, hydrolyzed polyvinyl acetate (75-95% polyvinyl alcohol), acryla- mide. methyl vinyl ether and so forth can be used. Other polymers include water-soluble forms of starch and cellulose and particularly derivatives such as sodium carboxy methylcellulose and the like. Natural proteins are useful, too; examples include gelatin and the like. In general, the useful materials are characterized by water- solubility and compatibility to form a base carrier suitable for loading the detergent in quantities from 1 to about 10% and where desired up to quantities of 25-35%. Such polymers are useful in amounts of from about 0.5% to about 10% and preferably from about 1% to 8%. Typical usage would be 1.5%, 2%0 2.5%, 3% or 4%,, especially with sodium polyacrylate. Thus the ratio of the polyphosphate to the polymer 7 M (ignoring any moisture present) may be in the range 190..li 100:1f 60:1f 45:1, 36:1, 30:1 or 20:1 to 10:1 or 8:1 or even 2.5:1 or 1.5:1. Pref erably it is in the range 190:1 to 8:1 e. g. 100:1 to 10:1, especially 25:1 5 to 50:1 or 35:1 to 40:1. The molecular weights of the synthetic polymers may vary from several hundred to several million, e.g. at least 600, 1200,, 2000y 5000j, 150j000r 500j00OF 1p000j000y 5j000r000 and the like. After the base bead has been prepared, it is used as an absorbent or carrier for the detergent. The latter are preferably non-ionic surfactants which, in liquid form are preferably non-ionic surfactants which. in liquid f orm are sprayed on to the base beads. The more desirable non-ionic detergent materials are generally pasty to waxy at room temperature or at least sprayable as a liquid at somewhat elevated temperatures e.g. at least 300C, 400C1 600Ce 800C or 1000C.

The nonionic detergent materials comprise any of the class designated as nonionic and generally comprises the oxyalkylated derivatives (preferably oxyethyl or mixed oxypropyloxyethyl) of hydrophobic base moieties of about C8 to C30 carbon atom content of such functional types as alcohols, thioalcohols, esters. acids and amides. The preferred compounds are oxyethylated and mixed oxypropylated-oxyethylated aliphatic alcohols of Clo to C180 The non-ionic detergents are the preferred types because of their physical characteristicsi namely being liquifiable and sprayable as well as low foaming, since one of the major characteristics of a detergent which adversely affects the cleaning efficacy of a dishwashing composition is a high level of foam. This is due primarily to the fact that the cleaning action is 8 proportional to the f orce of the jets of water impinging on the dishes. etc., and high levels of foam and thick or dense foam reduce this force and thus the cleaning action.

A general formula for preferred non-ionics is:

1 R R---OCH2CH---n0H (I) wherein R represents a hydrogen atom or a Cl 0 to Cl 8 alkyl group and preferably a linear alkyl group. Ri represents a hydrogen atom or a methyl group and n is an integer from 20 to 150, preferably 5 to 50 and more preferably 5 to 20. Where R represents a hydrogen atom the oxyalkyl groups are oxypropyl as a hydrophobe backbone with oxyethyl or oxyethyl and oxypropyl terminating groups.

Compounds where R represents a hydrogen atom generally have the following formula:

HO---(-CH CH 0 ? CHICH10) ( CH CH 0-+_-H (I1) 2 2 q C. 4. m 2 2 p where m may range from 3 to 50 or more and p and q may range similarly as n for Formula Ii i.e. from 20 to 150 preferably 5 to 50 and more preferably 5 to 20.

Illustrative compounds include:

1) n-tridecanol-+ 7.E.O. (EO is ethylene oxide).

2) n-tetradecyl alcohol + 8.E.O.

3) n-hexadecylalcohol + 8.E.O.

4) a C12-C14 linear alcoho' containing 55% oxy alkyl of which 42% are ethoxy and 58% propoxy in a random distribution.

11 1 Z 9 5) A C18 alkyl linear alcohol containing 57% ethylene oxide. 6) CH3 1 HO---(-CH2CH20 CH2CHO),,)(-CH2CH20)5H.

Mixed carbon chain lengths are often, and typically, used since they are very often quite readily available as mixtures f rom both synthetic and natural sources.

The amount of nonionic may range from a few percent up to 35 to 40% on a weight for weight basis. It is preferred to use at least about 3 to 4%. Typical amounts would be 4%, 6%, or 8% and in some embodiments 20%, 25% or 30%. Thus the ratio of the base to the nonionic may be in the range 35:1 j 25:1, 16:1, or 12:1 to 4:1,, 3:1,, 2:1,, 1.75:1 or 1.5:1. Where high nonionic loading is desired,, then it is preferred to utilize some of the f ormula- inorganic polyphosphate as post-added in anhydrous (or very low moisture content e.g. 1%, 2% or 3%) form.

In general, while other inorganic alkaline materials may be used in preparing the non-ionic carrier phosphate bead,. it is usually less desirable to 2.5 use silicate at least as a major replacement for the polymer if not as only a minor replacement for the polymer materials. and the silicate where employed in this invention for its alkalinity and anti-corrosive benefits is best utilized as a post-added component.

The silicates which are used. in the compositions of the present invention and particularly those which are post-added as powders comprise any of the commer cially available alkali silicates available as powders, wherein the Na20 to Si02 molar ratio varies from 2:1 to 1:4 and preferably varies from 1:1 to 1:3.5. Typical and most preferred silicates are sodium and potassium silicates where the Na20 to S'02 molar ratio varies from 1:1 to 1:2.5 and especially the metasilicates 0:1 ratio).

The physical form of the particulate silicate may be any form i.e. any density, porosity, shape and particle size. Thus densities may range from a bulk density of 0.3 to one of 1.5 and preferably 0.4 or 0.5 to 0.7 or 0.8. 0.9 or 1.0.

Typical particle sizes for the post-added silicates may be a product of 20, 30, 40, 50, 60 mesh (U.S. Sieve Series which have openings 840, 590, 420, 297, and 250 microns across. respectively). A commercially available product with 80-85% or more between 40 and 60 mesh is very useful. Similarly a product with 84% between 10 and 65 mesh is excellent, 10 and 65 mesh (U.S. Sieve Series) have openings 2000 microns and between 210 and 250 mircrons across,.respectively.

One additional and particularly outstanding characteristic and feature of one aspect of the compositions of this invention is their relatively low bulk density as compared to the usual commercial products.

Thus for example, while commercial products may have densities of the order of 0.8 those of the present invention may be made having 20 to 50% less density.

The silicates used may be in the form of beads, hollow or otherwise, finely divided powder, regular and irregular and diverse shaped particles. Particularly preferred silicate- are available as Metsobeads from PQ Corporation and Britesil LD24. Mixtures of any of the foregoing may also, of course, be used.

c 11 The amount of silicate used may vary from a few percent to a significant and almo.st major amount such as 2%y 3% and 5% to 10%r 15%, 20%, 30% and 40%. Parti cularly preferred ranges are 5% to 25% and 5% to 15%.

The optional bleach which, however, is highly desirable and preferred can be any of those convention ally used in automatic dishwasher compositions. The chlorine bleaches described earlier with reference to the prior art can also be used in this invention.

Similar amounts may be used as e.g. 0.3% to about 10%. preferably 1% to 5% (by weight). In plac e of chlorineyielding (e.g. OCL-) bleaches, one may use oxygen bleaches such as sodium perborate monohydrate, sodium perborate tetrahydrate, sodium persulphate, sodium per- carbonate and so forth. Oxygen bleach levels may range from about 2% to 40 or 50% and preferably from about 5% to 30%.

Many other adjuvants may be added to the present compositions without adversely affecting their utility and performance. For example, bacteriocidesi enzymest anti-spotting agents, sheeting agents, glaze-damage inhibitors (e.g. boric acid anhydride) may be used in amounts from as little as 0.01% to 10% or 15% or more.

The invention may be put into practice in various 2.5 ways and a number of specific embodiments will be described to illustrate the invention with reference to the accompanying examples. Partst where usedi are by weight unless-,otherwise indicated.

EXAMPLE I

An aqueous slurry of anhydrous sodium tripolyphosphate powder (TPP), water and sodium_ polyicrylate powder is prepared at 45% solids leveli handled and spray dried as in Example 1 of Joshi U.S. Patent 12 4414129. Thus an aqueous slurry of 15.s parts by weight anhydrous.sodium tripolyphosphate powder, 1.20 parts of sodium polyacrylate and 34 parts by weight of water is 5 prepared. This slurry is brought to a temperature of about 140oF (60OC) and mixed well to form the hexahydrate phosphate salt and is subsequently heated to 190OF (88OC) and maintained at between 1900P (880C) and 200OF (93OC) to prevent hydration of the next. to be 10 added portion of the total sodium tripolyphosphate. 28.5 parts by weight of anhydrous sodium tripolyphosphate powder and 21.0 parts by weight water are added to the previously formed slurry at 190OF to 200OF (88930C) to form a crutcher mix contain 45 parts solids 15 (43.8 phosphate and 1.2 polyacrylate), and 55 parts water i.e. 45% solids.

The crutcher mix is supplied to a countercurrent 8 foot (2.4 m) high spray drying tower and is sprayed at a manifold temperature of 180OF (820C) and a pressure of 600-900 psig using a Whir1jet 15-1 or Fu11jet 3007 spray nozzle. An air inlet temperature at the base of the tower of about 600OF (316OC) is used in the spray tower.

Of the spray dried product the TPP comprises 89.55%, the polyacrylate 2.45% and the balance of 8% is moisture in the bead. The bead has a specific gravity of 0.5 and has considerable mechanical strength & The beads so produced are introduced into a rotary drum and post-sprayed with a nonionic surfactant (liquified) at a temperature of 120OF (490C) until 6% by we'ght of the nonionic (based on the weight of the beads after spraying) has been "loaded" on the carrier beads. The non-ionic is a C12-C14 linear alcohol v 13 containing about 55% of random oxyethyl and oxypropyl groups (42 wtA oxyethyl - 58 wtA oxypropyl groups). These groups are introduced into the alcohol using a mixed ethylene oxide - propylene oxide stream. The beads at the time of spraying are at a. temperature of about 1000 to 1050P (38 to 41OC). 680g of the "loaded" beads are then dry mixed with 125g of powdered sodium metasilicate (PQ Corporation Metsobeads). 102 grams of anhydrous sodium carbonate and 33g of sodium dichloro- isocyanurate dihydrate.

In use in an automatic dishwashert 37g of the above formulation are used (in lieu of 50g of commercial automatic dishwasher powder "A"). Excellent cleansing is obtained. The spotting and filming performance is better than the commercial material #@A', a state of the art powder.

EXAMPLE II

Example I is repeated except that the beads are loaded with 25% by weight of the non-ionic and the composition is varied somewhat to have the following components:

Base Beads of Ex. I Sodium metasilicate 1 WT. % 60.0 12.0 Sodium carbonate of Ex. 1 10.0 Nonionic of Ex. 1 15.0 Chlorine bleach of Ex. 1 3.0 100.0% the metasilicate used here is a high bulk density product (50 lbs/ft3).

EXAMPLE III Example II is repeated except that the amount of base beads is only 50% (and, therefore, non-ionic is 14 is only 12.5%). The additional "hole" of 12.5% in the formula is filled with sodium tripolyphosphate (anhydrous) which is post mixed and blended into the formula with the metasilicatei carbonate and bleach.

EXAMPLES IVAj IVB and IVC, VA, VB and VC and VIA, VIB and VIC.

The previous examples are repeated using as the non-ionic in each instance, the following:

Examples 10 IV, V and VIA C18 linear alcohol containing 57% condensed ethylene oxide. Olin SLF-18-polytergent. n-tetradecylalcohol + 8 moles of ethylene oxide.

In preparing the compositions of this invention, the usual equipment may be used. Examples include Patterson Kelly twin shell blender for batch operation and a Patterson Kelly Zig-Zag blender for continuous processing.

IV, V and VIB IV, V and VIC 11 1

Claims

1. A free-flowing, automatic dishwashing deter5 gent powder composition comprising water-soluble, inorganicr polyphosphate baser non-ionic surfactant carried by the said base and admixed therewith.powdered watersoluble alkali silicate.

2. A composition as claimed in Claim 1 in which the polyphosphate base is a spray-dried bead-like product and comprises from about 50 to 95% by weight, the non-ionic from about 2% to 40% by weight and the silicate from about 2% to 40% by weight.

is

3. A composition as claimed in Claim 1 or Claim 2 in which the polyphosphate is sodium tripolyphosphate, the non-ionic is a C10-C18 linear alcohol condensed with at least 5 moles of ethylene oxide and 20 the silicate is sodium metasilicate.

4. A composition as claimed in Claim 1, 2 or 3 including a water-soluble polymer in the polyphosphate base.

5. A composition as claimed in Claim 4 in which the polymer is a polyacrylate and comprises 0.5% to 10% by weight of the composition.

6. A composition as claimed.in any one of Claims 1 to 5 including a bleaching agent.

7. A composition as claimed in Claim 6 in which 16 the bleaching agent is a chloroisocyanurate or an alkali metal or calcium hypochlorite.

8. A composition as claimed in any one of Claims 1 to 7 including powdered alkaline salts other than polyphosphate.

9. A composition as claimed in Claim 1 substantially as specifically described herein with reference to the accompanying examples.

10. A detergent powder composition useful as or in the preparation of a dishwasher detergent powder composition comprising (A) water soluble inorganic powder base comprising (i) polyphosphate, (ii) water soluble polymer, and (iii) moisture; and (B) nonionic detergent carried on or in the said powder base.

11. A detergent composition as claimed in Claim 10 in which the ratio of (A) to (B) is 15:1 to 16:1 or more broadly 10:1 to 20:1.

12. A detergent composition as claimed in Claim 10 or Claim 11 in which the ratio of polyphosphonate (i) to polymer (ii) is 35:1 to 40:1 or more broadly 25:1 to 50:1.

13. A detergent composition as claimed in Claim 10 substantially as specifically described herein with reference to the examples.

R 17 v

14. A dishwasher detergent powder composition incorporating a composition as claimed in any. one of Claims 10 to 13.

15. A method of making a free-flowing automatic dishwashing composition comprising preparing an aqueous slurry of water-soluble inorganic phosphate and a minor amount of a polymeri spray drying to form essentially hollow beads. absorbing thereon from 2% to 40% by weight based on the weight of the beads of a non-ionic surfactant having a melting point below about 1500C by spraying the said nonionic in liquified form onto the said beads and thereafter dry mixing the said beads with powdered sodium silicate.

16. A method as claimed in Claim 15 in which a powdered chlorine yielding bleaching agent is dry blended along with the silicate.

17. A method as claimed in Claim 15 substantially as specifically described herein with reference to the accompanying examples.

18. A composition as claimed in Claim 1 whenever made 'by a method as claimed in any one of Claims 15 to 17.

19. A method for cleaning dishes and the like in an automatic dishwasher which comprises adding to the dishwashert preferably to the dispenser means thereof. a free-flowing composition as claimed in any one of Claims 1 to 9 or Claim 14 or Claim 18 and thereafter putting the machine through its normal washing cycle.

Published 19813 at The Patent Offire. State House. 6671 High Holborn, London WC1R 4TP.F'urther copies maybe obtained from The Patent office, IRR:5 3RD. Printed bv MultiDlex techniques ltd. St Mary Cray, Kent. Con. 1187.