Sprayed granule

A detergent composition comprises detergent particles, each particle having a substantially anhydrous coating comprising a fluorescent whitening agent and a nonionic surfactant. A process for the preparation of the said detergent composition comprises spraying base detergent particles with a substantially anhydrous mixture comprising the fluorescent whitening agent and the nonionic surfactant.

FIELD OF THE INVENTION 
The present invention relates to a novel detergent composition and a 
process for preparing the same, and in particular to the provision of a 
laundry composition having improved whiteness as perceived by the 
consumer. 
BACKGROUND OF THE INVENTION 
The use of whitening agents, or brighteners, in laundry applications to 
whiten fabrics has been widespread since the mid-1970s. Since then, much 
research has been carried out into the properties of such whitening 
agents, and many different compositions including such agents have been 
described in the literature. However, most applications of whitening 
agents have been for the purpose of fabric whitening, rather than 
whitening of the detergent composition itself. 
WO 94/05761 discloses a process for preparing a high density granular 
detergent composition in which the bulk density of the detergent 
composition is increased by spraying detergent particles with a liquid and 
then dusting with a fine powder in a rotating drum or mixer. It is 
preferred that the liquid comprise a nonionic surfactant. Optionally, the 
liquid may also include other ingredients, such as perfume or a slurry, in 
water, of an optical brightener. The Examples describe the use of a 20% 
aqueous solution of optical brightener. 
However, a problem with mixing a nonionic surfactant with water is that 
this can lead to the formation of flakes of nonionic surfactant which tend 
to block the spray nozzle, thereby interrupting the process and requiring 
cleaning of the nozzle before the process can re-start. Furthermore, the 
use of an aqueous spray tends to be detrimental to the stability of the 
final detergent composition because water tends to react with and/or 
promote reaction of components of the composition. 
JP-A-07286198 discloses a process for preparing a granular nonionic 
detergent composition comprising spray-drying detergent particles 
containing 1% by weight of a nonionic surfactant and 0.01% by weight of a 
brightener. The brightener is first dissolved and/or dispersed in the 
nonionic surfactant, and is then granulated with other ingredients to form 
detergent particles prior to spray-drying. The process is designed to 
prevent unevenness of fluorescence of textile articles during washing. 
SUMMARY OF THE INVENTION 
According to a first aspect of the present invention, a detergent 
composition comprises detergent particles, each particle having a 
substantially anhydrous coating comprising a fluorescent whitening agent 
and a nonionic surfactant. 
The composition of the present invention has improved whiteness properties, 
even with very low levels of whitening agent, as compared to a composition 
in which the whitening agent is present throughout the detergent 
particles, as disclosed in JP-A-0728198, discussed above. 
According to a second aspect of the present invention, a process for 
preparing a detergent composition comprises spraying detergent particles 
with a substantially anhydrous mixture comprising a fluorescent whitening 
agent and a nonionic surfactant. 
As the process of the present invention substantially excludes the presence 
of water during spraying of the whitening agent/nonionic surfactant 
mixture, it overcomes two major problems experienced in the prior art when 
spraying nonionic surfactant when wet. In addition, a dramatic increase in 
the whiteness of the resulting product is observed. 
According to a third aspect of the present invention, the use of a 
substantially anhydrous mixture comprising a fluorescent whitening agent 
and a nonionic surfactant improves the whiteness properties of detergent 
particles, when the detergent particles are sprayed with the said mixture. 
DESCRIPTION OF THE INVENTION 
Prior to spraying the detergent particles, a substantially anhydrous 
mixture of whitening agent and nonionic surfactant is prepared by 
dispersing or partially dissolving the whitening agent in the nonionic 
surfactant, preferably with mixing to achieve a substantially homogenous 
mixture. The homogeneity of the mixture may be assessed using, for 
example, a UV lamp, thereby determining uniformity of fluorescence. The 
temperature at which the whitening agent and the nonionic surfactant are 
mixed is selected so as not to damage either of those components. 
Typically, however, the temperature will be in the range 25-80.degree. C., 
and preferably 30-60.degree. C. 
In the context of the present Application, by substantially anhydrous we 
mean that the amount of water present in the mixture of whitening agent 
and nonionic surfactant-is less than 5% by weight of that mixture, 
preferably less than 3% by weight, and more preferably less than 1% by 
weight. Most preferably, the mixture should contain no added water above 
that included in the commercially available forms of the whitening agent 
and the nonionic surfactant. For instance, some nonionic surfactants may 
include around 0.5% by weight water. 
The ratio of whitening agent: nonionic surfactant included in the mixture 
to be sprayed onto the detergent particles will depend, in part, on the 
nature of the whitening agent and the nonionic surfactant, and also in the 
nature of the final product into which the coated particles are to be 
incorporated. Generally, however, the ratio of whitening agent: nonionic 
surfactant will be in the range 1:500 to 1:5, and typically 1:400 to 1:10, 
by weight. It may be preferred to use a ratio of whitening agent: nonionic 
surfactant of 1:75 to 1:200 by weight for compact products, a ratio of 
1:150 to 1:400 by weight for "big-box" products, and a ratio of 1:5 to 
1:50 by weight for individual detergent additives, eg. in agglomerate, 
capsule or exudate form. 
The whitening agent is preferably a biphenyl distyryl compound, such as 
disodium 4,4'-bis(2-sulphostyryl)biphenyl, otherwise known as Brightener 
49 or Tinopal CBS (trade name, supplied by Ciba Geigy), or a coumarin 
compound, such as Tinopal SWN (trade name, suppled by Ciba Geigy). 
However, other whitening agents known in the art may also be suitable for 
use in the present invention, including benzidene sulfone disulfonic acids 
(BS), naphthotriazoylstilbene sulfonic acids (NTSA), amino coumarins (AC) 
and diphenylpyrazolines (DP), and derivatives thereof. 
Any suitable nonionic surfactant, or mixture of nonionic surfactants, may 
be used, provided that this is capable of forming a substantially 
homogenous dispersion, or solution, with the whitening agent. For 
instance, suitable nonionic surfactants include water-soluble condensation 
products of aliphatic alcohols having from 8 to 22 carbon atoms, in either 
straight or branched configuration, and which are optionally ethoxylated, 
for instance with 3 to 100 mols of ethylene oxide per mol of alcohol. 
Preferred are the condensation products of alcohols having 9 to 15 carbon 
atoms, with 3 to 80 mols of ethylene oxide per mol of alcohol. 
Typically, the amount of the whitening agent/nonionic surfactant mixture 
sprayed onto the detergent particles will constitute 0.1 to 10%, 
preferably 0.2 to 5%, by weight of the total particle weight. This means 
that the amount of whitening agent present can be as low as 0.01% by 
weight, and yet still provide beneficial results with regard to the 
whiteness of the composition. 
The base detergent particles themselves, i.e. the particles onto which the 
whitening agent/nonionic surfactant mixture is sprayed, may comprise any 
suitable detergent components. For instance, the detergent particles may 
comprise surfactants selected from anionic, zwitterionic, ampholytic and 
cationic surfactants, and mixtures thereof The detergent particles may 
also comprise a nonionic surfactant, which may be the same or different to 
the nonionic surfactant used to coat those particles. Suitable examples of 
such surfactants include any of those disclosed in WO-A-9405761. 
The base detergent particles may also include a whitening agent, which may 
be the same or different to the whitening agent used to coat the 
particles. Any conventional whitening agent is suitable for this purpose. 
The base detergent particles may also include a builder, which may be 
selected from conventional builders for use in laundry detergents. 
Suitable examples include aluminosilicate ion exchange materials, neutral 
or alkaline salts, inorganic phosphate builders, nonphosphorous organic 
builders and polymeric builders, and any of the builders disclosed in 
WO-A-9405761. 
Other ingredients commonly used in detergent compositions can also be 
included in the compositions of the present invention. Examples of such 
ingredients are disclosed in WO-A-9405761. 
The base detergent particles may be prepared by any of the known methods. 
For instance, in one method each component is metered by weight onto a 
moving belt, and then blended together in a rotating drum or mixer to 
agglomerate the separate components. In another method, a number of high 
active pastes, typically at least 40% by weight active, are agglomerated, 
for instance as described in any of EP-A-0508543, EP-A-0578872, 
EP-A-0618289 and EP-A-0663439. In yet another method, the detergent 
particles may be prepared by forming a slurry of the individual 
components, and then spray-drying the slurry to produce a "blown powder". 
The method of preparation used will generally depend upon final form of 
product required, and the final product may contain particles prepared by 
a number of different methods. 
The whitening agent/nonionic surfactant mixture may be sprayed onto the 
base detergent particles by any conventional spraying means. For instance, 
a Loedige CB mixer may be used. The rate at which the mixture is sprayed 
onto the detergent particles will vary according to the method of 
spraying, but will typically be in the range 0.5 to 5 tonnes/hr for a 
commercial process. 
After the detergent particles have been sprayed with the whitening 
agent/nonionic surfactant mixture they may be slightly sticky in nature. 
In this case, it may be preferred to dust the detergent particles with a 
processing aid, typically in the form of a fine powder having a particle 
size of up to 100 .mu.m, but generally up to 10 .mu.m, such as a zeolite, 
silica, clay, carbonate or starch, or any other suitable material. 
The final, coated, detergent particles may be used as a detergent 
composition by themselves, for instance if each particle comprises a 
mixture of detergent components of if the composition comprises different 
particles comprising different detergent components. Alternatively, or 
additionally, the coated detergent particles may be mixed with other 
particulate detergent materials, as are conventionally used in the laundry 
field. The present invention is further illustrated by the following 
Examples, in which, where not otherwise stated, all amounts are given in % 
by weight of the total composition, and the abbreviations used have the 
following meanings: 
______________________________________ 
LAS Sodium linear C.sub.11-13 alkyl benzene sulfonate 
TAS Sodium tallow alkyl sulfate 
CxyAS Sodium C.sub.1x -C.sub.1y alkyl sulfate 
C46SAS Sodium C.sub.14 -C.sub.16 secondary (2,3) alkyl sulfate 
CxyEzS Sodium C.sub.1x -C.sub.1y alkyl sulfate condensed with z moles 
of 
ethylene 
oxide 
CxyEz C.sub.1x -C.sub.1y predominantly linear primary alcohol 
condensed with an average of z moles of ethylene oxide 
QAS R.sub.2.N.sup.+ (CH.sub.3).sub.2 (C.sub.2 H.sub.4 OH) with 
R.sub.2 = C.sub.8 -C.sub.14 
Soap Sodium linear alkyl carboxylate derived from 
80/20 mixture of tallow and coconut fatty acids 
CFAA C.sub.12 -C.sub.14 (coco) alkyl N-methyl glucamide 
TFAA C.sub.16 -C.sub.18 alkyl N-methyl glucamide 
TPKFA C.sub.12 -C.sub.14 topped whole cut fatty acids 
STPP Anhydrous sodium tripolyphosphate 
TSPP Tetrasodium pyrophosphate 
Zeolite A 
Hydrated sodium aluminosilicate of formula 
Na.sub.12 (Al0.sub.2 SiO.sub.2).sub.12.27H.sub.2 O having a 
primary 
particle size in the range from 0.1 to 10 .mu.m (weight 
expressed on an anhydrous basis) 
NaSKS-6 Crystalline layered silicate of formula - Na.sub.2 Si.sub.2 
O.sub.5 
Citric acid 
Anhydrous citric acid 
Borate Sodium borate 
Carbonate 
Anhydrous sodium carbonate with a particle size 
between 200 .mu.m and 900 .mu.m 
Bicarbonate 
Anhydrous sodium bicarbonate with a particle size 
distribution between 400 .mu.m and 1200 .mu.m 
Silicate 
Amorphous sodium silicate (SiO.sub.2 :Na.sub.2 O = 2.0:1) 
Sulfate Anhydrous sodium sulfate 
Citrate Tri-sodium citrate dihydrate of activity 86.4% 
with a particle size distribution between 425 .mu.m 
and 850 .mu.m 
MA/AA Copolymer of 1:4 maleic/acrylic acid, average 
molecular weight about 70,000 
AA Sodium polyacrylate polymer of average 
molecular weight 4,500 
CMC Sodium carboxymethyl cellulose 
Cellulose 
Methyl cellulose ether with a degree of polymerization 
ether of 650 available from Shin Etsu Chemicals 
Protease 
Proteolytic enzyme of activity 4KNPU/g sold by 
NOVO Industries A/S under the tradename Savinase 
Alcalase 
Proteolytic enzyme of activity 3AU/g sold by NOVO 
Industries A/S 
Cellulase 
Cellulytic enzyme of activity 1000 CEVU/g sold by 
NOVO Industries A/S under the tradename Carezyme 
Amylase Amylolytic enzyme of activity 120KNU/g sold by 
NOVO Industries A/S under the tradename Termamyl 120T 
Lipase Lipolytic enzyme of activity 100KLU/g sold 
by NOVO Industries A/S under the tradename Lipolase 
Endolase 
Endoglucanase enzyme of activity 3000 CEVU/g sold 
by NOVO Industries A/S 
PB4 Sodium perborate tetrahydrate of nominal 
formula NaBO.sub.2.3H.sub.2 O.H.sub.2 O.sub.2 
PB1 Anhydrous sodium perborate bleach of 
nominal formula NaBO.sub.2.H.sub.2 O.sub.2 
Percarbonate 
Sodium percarbonate of nominal formula 
2Na.sub.2 CO.sub.3.3H.sub.2 O.sub.2 
NOBS Nonanoyloxybenzene sulfonate in the form of 
the sodium salt 
NAC-OBS (6-nonamidocaproyl)oxybenzene sulfonate 
TAED Tetraacetylethylenediamine 
DTPA Diethylene triamine pentaacetic acid 
DTPMP Diethylene triamine penta(methylene phosphonate), 
marketed by Monsanto under the Tradename Dequest 2060 
EDDS Ethylenediamine-N,N'-disuccinic acid, (S,S)- 
isomer in the form of its sodium salt. 
Photoacti- 
Sulfonated zinc phthlocyanine encapsulated in 
vated bleach 
dextrin soluble polymer 
Brightener 1 
Disodium 4,4'-bis(2-sulphostyryl)biphenyl 
Brightener 2 
Disodium 4,4'-bis(4-anilino-6-morpholino-1,3,5- 
triazin-2-yl)amino stilbene-2,2'-disulfonate 
HEDP 1,1-hydroxyethane diphosphonic acid 
PEGx Polyethylene glycol, with a molecular weight 
of x 
PEO Polyethylene oxide, with an average molecular 
weight of 50,000 
TEPAF Tetraethylenepentaamine ethoxylate 
PVP Polyvinylpyrolidone polymer, with an average 
molecular weight of 60,000 
PVNO Polyvinylpyridine N-oxide polymer, with an 
average molecular weight of 50,000 
PVPVI Copolymer of polyvinyipyrolidone and 
vinylimidazole, with an average molecular weight of 20,000 
QEA bis[(C.sub.2 H.sub.5 O)(C.sub.2 H.sub.4 O).sub.n ]CH.sub.3 
--N.sup.+ --C.sub.6 H.sub.12 -- 
N.sup.+ (CH.sub.3)bis[(C.sub.2 H.sub.5 O)--(C.sub.2 H.sub.4 
O).sub.m) where n = from 20-30. 
SRP 1 Sulfobenzoyl and capped esters with 
oxyethylene oxy and terephtaloyl backbone 
SRP 2 Diethoxylated poly (1, 2- propylene 
terephtalate) short block polymer 
Silicone 
Polydimethylsiloxane foam controller with siloxane- 
antifoam 
oxyalkylene copolymer as dispersing agent with a ratio of 
said foam controller to said dispersing agent of 
10:1 to 100:1 
Wax Paraffin wax 
Levante Perfume 
______________________________________