C4501/C
FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)


FAST RELEASE GRANULES
HINDUSTAN UNILEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed


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FAST RELEASE GRANULES
FIELD OF INVENTION
5 The present invention relates to granule conferring improved delivery of antioxidants to wash liquor.
BACKGROUND OF INVENTION
10 Rapid delivery of adjuncts to a wash medium is important
because it is necessary to have active adjuncts present in the wash liquor for the maximum time so that they perform in the most efficacious manner.
15 EP 570237, GB 1570128, GB 2348436, GB 2095274 and GB 2097419 disclose granules comprising bentonite and non-ionic surfactant. The granules may optionally comprise antioxidants.
20 GB 1557568 discloses a granular laundry composition
comprising an agglomerate of (a) from 1 to 50% by weight of the agglomerate of a quaternary ammonium surface active agent, and (b) from 10 to 90% by weight of the agglomerate of an organic acid precursor as activator for a persalt
25 bleaching agent. It may also be desirable, especially if nonionic surface-active agents are mixed in prior to the spray-drying operation, to incorporate from 0.01% to 10%, expressed by reference to the non-ionic surfactant of an antioxidant. Further optional ingredient is an ion-
30 exchangeable smectite clay, such as-Bentonite.

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SUMMARY OF INVENTION
The present invention provides a granule that releases an antioxidant rapidly into a wash medium. 5
In one aspect of the present invention there is provided a granule comprising: (i) a bentonite particle; (ii) nonionic surfactant; and , 10 (iii) an antioxidant, wherein the antioxidant is dissolved
in the non-ionic surfactant forming an
antioxidant/non-ionic solution, wherein the weight ratio of antioxidant to non-ionic is at least 5:100, and the weight ratio of antioxidant/non-ionic 15 solution to bentonite is in the range from 10:100 to 1:1, preferably 10:100 to 50:100, more preferably 20:100 to 40:100.
The maximum weight ratio of antioxidant to non-ionic is 20 determined by the solubility of the antioxidant in the non-ionic; in any event the preferred maximum weight ratio of antioxidant to non-ionic is 1:1.
In another aspect of the present invention there is provided 25 a method of preparing a clay granule comprising the steps
of:
(i) dissolving the antioxidant in a non-ionic surfactant, and mixing with particulate bentonite; and,
(ii} granulating, 3 0 wherein the weight ratio of antioxidant to non-ionic is at
least 5:100 and the weight ratio of antioxidant/non-ionic

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solution to bentonite is in the range from 10:100 to 1:1.
In a further aspect of the present invention there is provided a method of treating a textile with the antioxidant 5 granules of the present invention in an aqueous medium, followed by rinsing and drying the textile.
Treatment is preferably carried out in the domestic context, at temperature between 10 to 60 °C, preferably 15 to 40 °C. 10
DETAILED DESCRIPTION OF THE INVENTION The Granule
The granule is preferably a sieve fraction in the range 180 15 to 1400 microns. The granule is preferably used in a
laundry detergent powder formulation in the range from 0.1 to 5 wt %.
20 Bentonite
Bentonite is a widely used clay and is commercially available as a fine powder. A granular form may also be used.
2 5 Antioxidant
Anti-oxidants are substances as described in Kirk-Othmers . (Vol 3, pg 424) and in Uhlmans Encyclopedia (Vol 3, pg 91) and CRC Press Oxidation Inhibition in Organic Materials Vols I and II, Eds. Jan Pospisil and Peter P. Klemchuk: ISBN 0-
30 8493-4767-X and 0-8493-4768-8.

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10
15

One class of anti-oxidants suitable for use in the present invention is alkylated phenols having the general formula:
OH
wherein R is C1-C22 linear or branched alkyl, preferably methyl or branched C3-C6 alkyl; C3-C6 alkoxy, preferably methoxy; Rl is a C3-C6 branched alkyl, preferably tert-butyl; x is 1 or 2. Hindered phenolic compounds are preferred as antioxidant.
Another class of anti-oxidants suitable for use in the present invention is a benzofuran or benzopyran derivative having the formula:

R4 R50 \x-4^/ B\^X

wherein Rl and R2 are each independently alkyl or Rl and R2 can be taken together to form a C5-C6 cyclic hydrocarbyl moiety; B is absent or CH2; R4 is C1-C6 alkyl; R5 is 20 hydrogen or -C(0)R3 wherein R3 is hydrogen or C1-C19 alkyl; R6 is C1-C6 alkyl; R7 is hydrogen or C1-C6 alkyl; X is -CH20H, or -CH2A wherein A is a nitrogen comprising unit, phenyl, or substituted phenyl. Preferred nitrogen comprising

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A units include amino, pyrrolidino, piperidino, morpholino, piperazino, and mixtures thereof.
Other suitable antioxidants are found as follows. A 5 derivative of a-tocopherol, beta-tocopherol, gamma-
tocopherol, delta-tocopherol, and alkyl esters of gallic acid, especially octyl gallate and dodecyl gallate.
Another example of suitable antioxidants are the class of 10 hindered amine light stabilisers (HALS), particularly those based 2,2,6,6-tetramethylpipiridines.
Preferred anti-oxidants are phenols, in particular 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, and 15 mixtures of 2 and 3- tert-butyl-4-methoxyphenol. A preferred antioxidant is 4,4'-isopropylidenebis(2,6-dimethylphenol).
Mixtures of antioxidants may be use and in particular
mixtures that have synergic antioxidant. 20
Non-ionic surfactant
The non-ionic surfactant may be selected from alcohol
ethoxylates, R-(OCH2CH2)nOH, where R is an alkyl chain
typically Ci0 to Cis and n is 1 to 20, preferably 3 to 9, most 25 preferred n = 7. Preferred nonionic surfactants such as C12-
Cis alkyl ethoxylates {"AE") including the so-called narrow
peaked alkyl ethoxylates.
In a further preferred aspect, the non-ionic is preferably 30 selected from materials having an alkyl chain length in the

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range C10 to C18, with an ethoxylate number in the range 1 to 10, preferably 3 to 7.
Binder 5 The non-ionic/antioxidant may serve as a binder with out the need for other binders to be present. It is however preferred that a binder other than the non-ionic surfactant is used. Preferably, the other binder is present between 0 and 20 wt% of the total granule weight, preferably 3 to 15% 10 and more preferably 5 to 10%.
The binder may be water but may be any other suitable material that serves to hold individual particles of bentonite/non-ionic together. Polycarboxylate binders are 15 preferred; commercial examples of such are available from
BASF, for example: Sokalan CP 10, Sokalan CP 45, Sokalan CP 5, Sokalan CP 7, Sokalan CP 9, Sokalan PA 15, Sokalan PA 20, Sokalan PA 40.
2 0 Experimental
Preparation of Granules: Anti-oxidant/Bentonite Granules 1) Bentonite/2,6-di-tert-butyl-4 methylphenol l.Og of 2,6-di-tert-butyl-4 methylphenol was dissolved in 9.0g coco7EO nonionic to obtain a anti-oxidant/nonionic
25 solution. 10.Og of bentonite powder {Optigel CK - Sud
Chemie) was then mixed thoroughly in a pestle and mortar with 2.5g of the anti-oxidant/nonionic solution, forming a free-flowing powder. The resulting free-flowing powder was. then granulated with 2.7g of Sokalan CP5 (BASF) (40%). The
30 granules were then dried in an oven at 80°C and finally

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sieved to provide a- granulate sized in the range 180 and 1000 microns.
2) Bentonite/4,4'-isopropylidenebis(2 , 6-dimethylphenol) 5 l.Og of 4,4' -isopropylidenebis (2, 6-dimethylphenol) was dissolved in 9.Og coco7EO nonionic, 10.0g of bentonite powder {Optigel CK - Sud Chemie) was then mixed thoroughly in a pestle and mortar with 2.5g of the anti-oxidant/nonionic solution, forming a free-flowing powder. 10 The resulting free-flowing powder was then granulated with 2.7g of Sokalan CP5 (BASF) (40%). The granules were then dried in an oven at 80°C and finally sieved to provide a granulate sized in the range 180 and 1000 microns.
15 3) Granule, prepared by high shear mixer granulation,
containing 11.6% 2,6-di-tert-butyl-4 methylphenol, 54.3% zeolite, 11.6% ascorbic acid and 22.5% PEG6000, where the 2,6-di-tert~butyl-4 methylphenol was added as a milled powder.
20
4) Granule, prepared by high shear mixer granulation,
containing 12.7% 2,6-di-tert-butyl-4 methylphenol, 53.2%
sodium sulphate, 12.7% ascorbic acid and 15.4% PEG6000,
where the 2,6-di-tert-butyl-4 methylphenol was added as a
2 5 milled powder.
5) Granule, prepared by high shear mixer granulation,
containing 12.0% 2,6-di-tert-butyl-4 methylphenol, 57.3%
zeolite, 12.0 ascorbic acid and 18.7% Genapol T-500
30 (Clariant) , where the 2, 6-di-tert-butyl-4 methylphenol was added as a melt.

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6) Granule, prepared by high shear mixer granulation, containing 12.6% 4, 4'-isopropylidenebis(2,6-dimethylphenol), 84.9% sodium sulphate and 2.6% Sokalan CP13S 5 (BASF), where the 4,4'-isopropylidenebis(2,6-dimethylphenol) was added as a milled powder.
RATE OF RELEASE METHOD
10 4g of detergent powder (in this instance Brazilian OMO MA) was dissolved in 1 litre of demineralized water at room temperature and stirred (magnetic stirrer) for 2 0 minutes in order for complete dissolution.
15 After the dissolution period, O.lg of the antioxidant
containing granules, sieve fraction 180 to 1000 microns, were added to the solution with constant stirring.
A small sample of the solution was taken after 5 minutes 20 using a 2ml syringe. This sample was immediately filtered through a Whatman Puradisc (1.0 micromol polyethersulfone membrane) filter. The filtered sample was analysed by HPLC to determine the percentage of antioxidant released.
25 The amount of anti-oxidant released into the wash solution after 5 minutes, for each of the examples, is shown in the following table.
30

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Example % Anti-oxidant
Released after 5
minutes
1 100
2 86
Comparative 3 12
Comparative 4 12
Comparat ive 5 36
Comparative 6 28

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We Claim:
1. A granule comprising:
(i) a bentonite particle; 5 (ii) non-ionic surfactant; and,
(iii) an antioxidant, wherein the antioxidant is dissolved in the non-ionic surfactant forming an antioxidant/non-ionic solution,
wherein the weight ratio of antioxidant to non-ionic is 10 at least 5:100 and the weight ratio of antioxidant/non-ionic solution to bentonite is in the range from 10:100 to 1:1.
2. A granule according to claim 1, wherein the non-ionic is
15 selected from materials having an alkyl chain length in
the range C10 to C18, with "an ethoxylate number in the range 1 to 10.
3. A granule according to claim 1 or 2, wherein the
20 antioxidant is selected from the group consisting of: 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, and 4,4'-isopropylidenebis (2,6-dimethylphenol).
25 4. A granule according to any preceding claim, wherein the granule comprises a binder other than a non-ionic surfactant binder in the range between 0 and 2 0 wt% of the total granule weight.

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5. A granule according to any preceding claim, wherein the antioxidant granules are a sieve fraction in the range 180 to 1400 microns.
5 6. A laundry detergent powder formulation comprising the
antioxidant granule, as defined in any preceding claim, in the range 0.1 to 5 wt %.
7. A method of preparing a clay granule comprising the 10 steps of:
(i) dissolving the antioxidant in a non-ionic
surfactant, and mixing with particulate bentonite; and,
(ii) granulating,
wherein the weight ratio of antioxidant to non-ionic is 15 at least 5:100 and the weight ratio of antioxidant/non-
ionic solution to bentonite is in the range from 10:100
to 1:1.
Dated this 7th day of August 2008