AU666918B2 - Granular percarbonate laundry bleach containing layered silicate stabilizer - Google Patents

Description

OPI "DATE 28/07/93 AOJF DATE 30/09/93 APPLN. ID 34224/93 PCT NUMBER PCT/US92/11222 AU9334224 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) F(51) International Patent Classification 5 (11) International Publication Number: WO 93/12843 A62D 3/00, C01B 15/037, 15/10 C09K 15/02, CUID 3/08, 3/395 Al (43) Internatioual Publication Date: 8 July 1993 (08.07.93) CIlD 7/14, 7/18 (21) International Application Number: PCT/US92/11222 (74)Agents: REED, David et al.; The Procter Gamble Company, 5299 Spring Grove Avenue, Cincinnati, OH (22) International Filing Date: 24 December 1992 (24,12.92) 45202 (US).

Priority data: (81) Designated States: AU, BB, BG, BR, CA, CS, FI, HU, JP, 92200005.4 3 January 1992 (03.01.92) EP KP, KR, LK, MG, MN, MW, NO, NZ, PL, RO, RU, (34) Countries for which the regional SD, UA, US, European patent (AT, BE, CH, DE, DK, or international application ES, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OAPI wasfiled: BE et al. patent (BF, BJ, CF, CG, Cl, CM, GA, GN, ML, MR, SN, TD, TG).

(71) Applicant (for all designated States except US): THE PROC- TER GAMBLE COMPANY [US/US]; One Procter Published Gamble Plaza, Cincinnati, OH 45202 With international search report.

(72) Inventor; and Inventor/Applicant (for US only) TRANI, Marina [IT/IT]; Via Gualtiero Serafino, 20, 1-00136 Rome (IT).

666918 (54) Title: GRANULAR PERCARBONATE LAUNDRY BLEACH CONTAINING LAYERED SILICATE STABILIZER (57) Abstract A granuler bleaching composition is disclosed which comprises an alkali metal salt of percarbonate and a crystalline layered silicate or mixtures thereof. Preferred compositions further comprise an anhydrous acidifiant agent. The compositions provide effective bleaching and are as stable as perborate based bleaching compositions.

WO 93/12843 PCF/US92/11222 1 GRANULAR PERCARBONATE LAUNDRY BLEACH CONTAINING LAYERED SILICATE STABILIZER Technical field The present invention relates to bleaching compositions for laundry. Granular laundry bleaching compositions are described which comprise percarbonate as the bleaching specie, said compositions being stable upon storage.

Background of the invention The inorganic perhydrate bleach most widely used in the context of laundry bleaching is sodium perborate in the form of either the monohydrate or tetrahydrate. However, concerns about the impact of boron salts on the environment have led to an increasing interest in other perhydrate salts, of which sodium percarbonate is the most readily available.

WO 93/12943 PCIF/US92/11222 2 Detergent compositions containing sodium peru bonate are known in the art. Percarbonate salts, particularly sodium percarbonate, are attractive pertlydrates for use in detergent compositions because they dissolve readily in water, are weight efficient and, after giving up their available oxygen, provide a useful source of carbonate ions for detergency purposes.

However, the inclusion of percarbonate salts in detergent compositions has been restricted hitherto by the relative instability of the bleach both as is and in use. Sodium percarbonate loses its available oxygen at a significant rate in the presence of ions of heavy metals such as iro:, copper and manganese and also in the presence of moisture, these effects being accelerated at temperatures in excess of about Moisture and heavy metal ions are unavoidable components of conventional granular laundry treatment compositions. Also percarbonate decomposition due to moisture becomes more of an issue during storage as laundry treatment products are often stored in humid environments when the product picks up moisture. This has resulted in marginally acceptable percarbonate bleach stability under Northern European summer conditions, where the average maximum temperature over the hottest months is from 21°C to 25 0 C, and unacceptable stability under temperatures higher than this.

Such conditions are found in the Middle East and Southern Asia and also in Southern Europe where average maximum temperatures are in the 27°C to 33 0 C range for the hottest summer month.

There has therefore been much activity by workers in the field to increase percarbonate stability so as to make it a viable component of detergent formulations. This activity has tended to concentrate on the protection of the percarbonate by coating the crystalline product or by inclusion of stabilising agents during its manufacture, or both. Thus, while it has proved possible to incorporate percarbonate salts in conventional detergent compositions so as to have acceptable percarbonate stability over periods reflecting normal product shelf life, the percarbonate salts have proved complex and expensive to manufacture. This has restricted their broadscale utilisation, as evidenced by the relatively small number of commercially available products containing percarbonate.

It would therefore be desirable to provide a granular laundry bleaching composition incorporating an alkali metal percarbonate bleach, said bleach displaying improved stability.

It would also be desirable to provide a granular laundry bleaching composition incorporating an alkali metal percarbonate bleach displaying improved stability, in which the percarbonate bleach does not require complex protection techniques.

Granular bleaching compositions comprising percarbonate have been described for instance in FR 2,385,837, US 4,428,914 and GB 1,553,505.

Crystalline layered silicate and their methods of preparation have been described for instance in EP-A-164 514, DE-A-34 17 649 and DE-A-37 42 043 and their application to the field of laundry treatment has been described in applicant's copending British applications GB 90 21 761.3, GB 90 18157.9 and GB 91 08639.7.

The composition according to the present invention also allow adequate control of the pH in the bleaching liquor, giving appropriate balance between bleaching performance and fabric safety.

Throughout the description and claims of this specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives or components or integers. Summary of the Invention Compositions according to the present invention are granular bleaching compositions comprising from 35 to 80% by weight of the total composition of an alkali metal salt of percarbonate bleach and from 5% to 80% by weight of the total composition of a crystalline layered silicate of formula NaMSiO 2 1 yH 2 0 wherein A 3 o c a *1 M is sodium or hydrogen, x is a number of from 1.9 to 4 and y is a number of from 0 to 20, or mixtures thereof. The compositions optionally contain filler salts and adjunct ingredients. Preferred compositions herein further comprise an anhydrous acidifying agent, preferably citric acid.

Detailed Description of the Invention As a first essential component, the compositions according to the present invention comprise an alkali metal salt of percarbonate, preferably sodium percarbonate. Sodium percarbonate is available commercially as a crystalline solid. Most commercially available material includes a low level of a heavy metal sequestrant such as EDTA, 1-hydroxyethylidene 1, 1-diphosphonic acid (HEDP) or an amino-phosphonate, that is incorporated during the manufacturing process.

For the purposes of the present invention, the percarbonate can be incorporated into detergent compositions without additional protection.

Whilst heavy metals present in the sodium carbonate used to manufacture the percarbonate can be controlled by the inclusion of sequestrants in the reaction mixture, it is preferred that the percarbonate be protected from heavy ee* *o WO 93/12843 PCUS92/11222 metals present as impurities in other ingredients of the product. It has been found that the total level of Iron, Copper and Manganese ions in the product should not exceed ppm and preferably should be less than 20 ppm in order to avoid an unacceptably adverse effect on percarbonate stability.

The compositions according to the present invention comprise me ,an \by weight of the total composition of percarbonate, up to 80% by weight of the total composition, preferably from 40% to The second essential component of the invention is a crystalline layered silicate. The crystalline layered silicates suitable for use herein are of the granular formula NaMSixO 2 x+..yH 2 0 wherein M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20, or mixtures thereof.

Crystalline layered sodium silicates of this type are disclosed in EP-A-164 514 and methods for their preparation are disclosed in DE-A-34 17 649 and DE-A-37 42 043. For the purposes of the present invention, x in the general formula above has a value of 2, 3 or 4 and is preferably 2.

More preferably M is sodium and y is 0 and preferred examples of this formula comprise theo 6 Yand forms of Na 2 Si 2 0 5 These materials are available from Hoechst AG FRG as respectively NaSKS-5, NaSKS-7, NaSKS-11 and NaSKS-6.

The most preferred material is Na 2 Si 2 0 5 NaSKS-6.

Crystalline layered silicates are incorporated either as dry mixed solids, or as solid components of agglomerates with other components.

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WO 93/12843 PCT/US92/11222 6 The compositions according to the present invention comprise from 5% to 80% by weight of the total composition of said crystalline layered silicates or mixtures thereof, preferably from 15% to As an optional but highly preferred component, the compositions according to the present invention further comprise an anhydrous acidifying agent or mixtures thereof.

The purpose of said acidifying agent is to control the alkalinity generated by the percarbonate in the bleaching liquor. Said agent need to be incorporated in the product in an anhydrous form, and to have a good stability in oxidizing environment. Suitable anhydrous acidifying agents for use herein are carboxylic acids such as citric acid, succinic acid, adipic acid, glutaric acid, 3 ketoglutaric acid, citramalic acid, tartaric acid and maleic acid. Other suitable acidifying agents include sodium bicarbonate, sodium sesquicarbonate and silicic acid. Highly preferred for use herein is citric acid.

Indeed, citric acid is commercially available in anhydrous form, it additionally acts as a builder and a chelant, and it is biodegradable. The compositions according to the present invention comprise from up to 15% by weight of the total composition of anhydrous citric acid, preferably from 2% to most preferably about Compositions in accordance with the invention can also comprise optional ingredients such as optical brighteners, anti dusting agents such as olefines and waxes, enzymes, chelants, dispersants, surfactants, soil release agents, photoactivated bleaches such as Zn phthalocyanine sulphonate, dyes, pigments and perfumes are examples of such optional ingredients and can be added in varying amounts as desired.

WO 93/12843 P~/US92/11222 7 Optional but highly preferred ingredients are peroxy carboxylic acids bleach or precursors thereof, commonly referred to as bleach activators, which are preferably added in a prilled or agglomerated form. Examples of suitable compounds of this type are disclosed in British Patent GB 1 586 769 and GB 2 143 231 and a method for their formation into a prilled form is described in European Published Patent Application EP-A-62 523. Preferred examples of such compounds are tetracetyl ethylene diamine (TAED), sodium 3, 5, 5 trimethyl hexanoyloxybenzene sulphonate, diperoxy dodecanoic acid as described for instance in US 4 818 425 and nonylamide of peroxyadipic acid as described for instance in US 4 259 201 and nnonanoyloxybenzenesulphonate (NOBS), and acetyl triethyl citrate (ATC) such as described in European Patent application 91870207.7.

The compositions according to the present invention naturally comprise inorganic filler salts such as alkali metal carbonates bicarbonates and sulphates. Such fillers, for instance sodium bicarbonate, may also act as acidifying agent as described herein above. Accordingly, sodium percarbonate is a preferred filler material for use herein.

The compositions according to the present invention can be made by a variety of methods well known in the art, including dry-mixing, spray drying, agglomeration and granulation and combinations thereof.

The compositions according to the present invention can be prepared with different bulk densities, from conventional granular products to so-called "concentrated" products with a bulk density above 600g/l).

WO 93/12843 PCr/US92/11222 8 Examples 1) Part A The following examples will illustrate the present invention. The following granular compositions are made by dry-mixing the listed ingredients in the listed proportions.: Compositions 1 2 3 4 5 6 Sodium percarbonate 40.0 35.0 54.0 55.0 46.0 47.0 TAED 8.7 7.6 11.7 9,5 Silicate layered SKS-6: 25.0 30.0 20.0 10.0 18.0 20.0 Anhydrous citric acid 10.0 12.0 12.0 5.0 5.0 Sodium sulphate 15.3 14.3 1.0 20.0 0.5 15.0 Sodium bicarbonate 5.0 18.0 NOBS 10.3 minors :up to 100% 2) Part B The following compositions were made by mixing the listed ingredients in the listed proportions. The self heating rates of the products were monitored as follows. The product is made and put in a bottle. The bottle is then put in an oven which is heated up to 706c. A probe in the product allows to monitor the temperature of the product.

As soon as the product reaches 70 0 c, the bottle is covered and the system is isolated in an adiabatic/thermo bell which maintains the temperature of the oven constant at 0 c as above. This places the product in adiabatic conditions and from thereon, the temperature of the product is monitored. The temperature increase thus measured is due to the self-heating of the product (runaway reaction).

The results below list three self heating rates, all in Oc/hour: SHR1 is the average temperature increase measured during the first two hours of adiabatic conditions; SHR2 is the average temperature increase measured during the three WO 93/12843 PC/US92/11222 9 following hours, and SHR3 is the average temperature increase measured beyond 5 hours. The table below lists the results obtained for various compositions, with and without crystalline layered silicate. In some cases the runaway reaction was out of control and experiments had to be interrupted for safety reasons. Such experiments are marked "ooc" (out of control).

Compositions 7 7a 8 8a 9 9a Sodium percarbonate 47.0 47.0 47.0 47.0 47.0 47.0 TAED 10.2 10.2 10.2 10.2 10.2 10.2 Silicate SKS-6 20.0 20.0 20.0 Citric acid 10.0 10.0 8.0 8.0 8.0 Sodium Sulphate 11.7 31.7 13.7 33.7 9.2 29.2 Sodium bicarbonate 4.5 SHR1* 2.3 4.5 2.2 4.0 2.5 3.9 SHR2** 0.6 8.9 0.6 8.0 0.5 7.7 SHR3*** 0 ooc 0 ooc 0 ooc Compositions 10 10a 11 lla 12 12a Sodium percarbonate 47.0 47.0 47.0 47.0 47.0 47.0 TAED 10.2 10.2 10.2 10.2 10.2 10.2 Silicate SKS-6 18.0 20.0 42.8 Citric acid 7.0 7.0 5.0 5.0 Sodium Sulphate 16.7 34.7 16.7 36.7 42.8 Sodium bicarbonate SHR1* 2.7 4.1 2.2 4.1 2.2 SHR2** 0.6 8.3 0.4 8.2 0.3 10.8 SHR3*** 0 ooc 0 ooc 0 ooc Comments: Compositions 7-12 show good thermal stability, and no temperature increase is reported after 5 hours storage and beyond. In the absence of crystalline layered silicate i.e. in compositions 7a-12a, self-heating rates measured were so high that experiments had to be stopped for safety purposes.

Claims (6)

1. A granular bleaching composition comprising: a) from 35% to 80% by weight, of a percarbonate alkali metal salt; b) from 5% to 80% by weight, of a crystalline layered silicate of formula NaMSixO 2 x+1-yH20 wherein M is sodium or hydrogen, x is a number of from 1.9 to 4 and y is a number of from 0 to 20, or mixtures thereof; and c) optionally filler salts and adjunct ingredients.

2. A composition according to claim 1 comprising from 2% to 15% by weight, of an anhydrous acidifying agent selected from the group consisting of citric acid, succinic acid, adipic acid, glutaric acid, 3-ketoglutaric acid, citramalic acid, tartaric acid, maleic acid, sodium bicarbonate, sodium sesquicarbonate, silicic acid, and i ixtures thereof.

3. A composition according to claim 2 comprising from 40% to 50% by weight, of the percarbonate alkali metal salt and from 15% to 25% by weight, of the crystalline layered silicate.

4. A composition according to claim 3 comprising a crystalline layered silicate having the formula NaMSixO2xl'+yH20, wherein x is 2, M is sodium and y is 0. A composition according to claim 2 wherein the anhydrous acidifying agent i is anhydrous citric acid. 20 6. A composition according to claim 5 comprising from 2% to 12% by weight, S* .of the anhydrous citric acid. S7. A composition according to claim 6 comprising 5% by weight, of the anhydrous citric acid.

8. A composition according to claim 1 wherein the adjunct ingredients are 25 members selected from the group consisting of optical brighteners, anti-dusting agents, enzymes, chelants, dispersants, surfactants, soil release agents, photoactivated bleaches, dyes, pigments, perfumes, and mixtures thereof.

39. A composition according to claim 1 substantially as herein described with reference to any one of the Examples. DATED: 28 December, 1995 THE PROCTER GAMBLE COMPANY By their Patent Attorneys <PHILLIPS ORMONDE FITZPATRICK INTERNATIONAL SEARCH REPORT International application No. PCT1US92J11222 A- CLASSIFICATION OF SUBJECT MALTIER IPC(S) :1A62D 3/QQ;CO1B3 15/037,15/10;CO9K 15/02;CIID 3/08,3/395,714, 7/18 US CL :7-52NS,99,100,174.2S,1S6.Z7,1S6,186.43 According to hnuational Patent Claaalfication (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) U.S. 252/95,99,100,174.25,186.27,1.86,186-43 Documentation searched otherThan miimum documentation to the extent that such documents are included in the fields searched NONE Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) NONE C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X EP,A, 0,337,217 (DANY) 1-3 18 OCTOBER 1989 See table 1, excamples, 3 and X,P USA 5,087,895 (DANY) 1-3 07 JANUARY 1992 See table 1, examples 3 and A USAk, 4,820,439 (RIECK) I1I AP'RIL 1989 Y USA 4,737,306 (WICHELHAUS) 1-3 12 APRIL 1988 See col. 14, line 63-col. 15, line 3 and Examples 11-17 Further documents are listed in the continuation of Box C. See patent family annex. Speci eaeorics of cited docuiana: r hier doumea ,ukbiahs after the heterautional filing date ot pnrqt date sad sot in cosfictwith the application but citd to uadengtandthe to be pan of paz mfloYe pacvaeo ter mtdin h ect atrier octt psblthe r a~ne he tesgieul ilig d± X. docutanot of pnrticuir relc-vasce the claumed invention cannot be arler ~cutea pulisud n a afer k kwaaionl f14 ac omidcn'd novel or esosot bo considered to involve an ioventive se docainsn which may tku w doubb an pdrycies t hich is when the docuiiecn taken slowe sci e so (oslaihtepocii indeofaohr lno o docianti of pastiuur relevance; the clanned inventiou cannot be apeda maso (maspeciied)cminsimein in volve an myastoive s"e when the docunt is dommwatt rfaing to an omt declousn, tue, ezhizums or other conahined with newc or wore other such docianeni, a" oombination aumn being okiviowt to a peeso attle In the an' documwA publiabod pior io te keetviol iling date bt laier than danmat nanber of die am= patent fanly the prineity date claimed DaM of the actual completion of the international search Date of mailing of the international search report 04 MARCH 1993 V Name and matilingi address of the ISA/US Attl-lrizod officer Commisuioner ofPtnsand Trademaris BOX PCT ENNS L. ALBRECI Wa&6hingtn D.C. 20231P Facsimile No. NOT APPLICABLE Teehone No. (703) 308-2525 Form PCT/ISA/210 (second shet)(July 1992)* INTERNATIONAL SEARCH REPORT International application No. PCTIUS92/1222 Box I (ibsawaim whecre cabtin claim were fmwd unsearchble (Continuation of kern 1 -Z first shect) This international report has not been established in respc of certain claim urler Article 17(2X&) for dhe Molowing reasons: 1. 0 Claimrs No&.: because they relate to subject matter not required to be searched by this Authority, namely: l Claims Nos.: -'because they relate to parts of the international application that do not comply with the prescribed requirements to such an extent that no meaningful international search can be carried out, specifically: 3. Fn1 Claims Nos.: 4-7 because they are dependent claims ad are not drafted in vavcordance with the second and third sentences of Rule 6.4(a). Bnx 11 Observations whcre unity of invention is lacking (Continuation or item 2 of first sheet) This International Searching Authority found multiple inventions in this international application, as follows: 1. As all required additional search fees were timely paid by the applicant, this internatiori iearch report w.vcrs all searchable claims. 2. As all searchable clams could be searched without effort justifying an additional fee, this Authority did not invite payment of any additional fee. 3. []As only some of the required additional search fees were timely paid by the applicant, this international search report covers only those claims fbr which fees wore paid, specifically claims No:.: restricted to the invention first mentioned in the claimsz; it is covered by clairms Nos.: Remark on Protest The additional search fees were accompanied by the applicant's protest. ni No pretest secompaiiied the payment of additional search fees. Form PCT(ISAf21O (continuation of first shcet(l))(July 199)*