PH12009000379A1 - Process for making a detergent composition having a fluorescer - Google Patents

Abstract

The invention relates to a process for the preparation of a non-tower detergent composiiton, that includes a fluorescer. A process for making a non-spray-dried detergent composition is disclosed, which includes a step of neutralisation of an acid precursor of an anionic surfactant, in which an aqueous solution or dispersion of a fluorescer is mixed with the precursor, prior to neutralisation, wherein temperature of the aqueous solution or dispersion is in the range of 60 to 80 C . The invention addresses the problem of uniformity in the distribution of the fluorescer in the powder composition, which is generally relatively lower.

Description

oo ' 1 : PROCESS FOR MAKING A DETERGENT COMPOSITION HAVING A FLUORESCER

FIELD OF INVENTION ;

The present invention relates to a process for the preparation of a detergent composition. In particular this invention relates to a process for making a Non-Tower ) detergent composition comprising a fluorescer. ¥ oo

BACKGROUND AND RELATED ART Sn ya

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Any discussion of the prior art throughout the specification should in no way be considered as an admission’ that such prior art is widely known or forms part o / the common ] general knowledge in the field. 7 /

Detergent powders generally include ingredients in addition to surfactants, which are necessary for good cleaning. These ingredients which provide the powder with desirable characteristics include fluorescers and perfumes. ]

Fluorescers have been used for many years in conventional J spray-dried and NTR (Non-Tower Route) powders so that the powder appears white and/or bright.

In the production of spray-dried powders, the fluorescer is generally incorporated into the slurry which is to be spray- dried, to produce the powder.

With the advent of high bulk density (abbreviated as BD) powders, for example having bulk density in excess of 750 kg/m’, new process routes have been proposed which involve subjecting a spray-dried powder to a "post-tower" mixing and densification process, or mixing and densifying the components of the detergent composition without the use of a spray-drying step (NTR process) for example as described in

EP367339 (Unilever, 1990).

Production of a detergent composition by mixing process typically involves contacting and mixing the liquid components with the solid components of the composition so that the liquid binds the solids, thereby forming particles of the composition. With further mixing, the particles increase in size to form granules. This step is known as agglomeration.

In NTR process, fluorescers are generally incorporated into the powder as a solid material in the mixing/densification step. In the dry-mix method of making detergent powders with the existing know how; it is generally observed that the distribution of fluorescer is not uniform. One way to overcome this problem is to dose a higher amount of the fluorescer. However, this is a relatively expensive solution.

WO 95/013358 Al (Unilever) describes a process of making high BD detergent powders by NTR route, by incorporating a fluorescer into the liquid component of the detergent composition to produce a pre-mix of the fluorescer in the form of a slurry, dispersion or suspension, which is then combined with the solid components in the mixing step to produce the particulate compositicn. The present inventors have found that the degree of uniformity of distribution of the fluorescer would be relatively low, as it is difficult to make a homogenous mixture of a liquid with solid components, especially at low 1liquid:solid ratios. This would lead to pockets of high and low fluorescer content.

US4309316 (CIBA GEIGY CORP, 1982) describes a process for production of spray-dried detergent powders containing a fluorescer. In this process, the fluorescer is first ‘ dissolved or dispersed in a mixture of water and polyvinyl alcohol or polyvinyl pyrrolidone, and this solution is added to the washing powder slurry and the slurry is dried in a conventional manner. It has been described that the solution or dispersion could also be subsequently sprayed onto the dried residual washing powder. Such a process 1s not suitable for making NTR powders, as NTR process does not involve any spray-drying.

JP11189799A (LION CORP, 1999) describes a process for producing high BD granular detergent powders containing a fluorescer. In this case, the liquid acid precursor of an anionic surfactant is neutralised with a granular alkaline builder containing a fluorescer mixed with it. The present inventors have observed that in such a process, there would be non-uniform mixing of the alkaline builder with the 1 fluorescer, as their individual levels of addition vary significantly. This non-uniform mixing in-turn would lead to non-uniform distribution of the fluorescer in the finished product, when this powder is added to the acid precursor. :

Therefore, the resultant composition has pockets that are rich in fluorescer, and some pockets that have no fluorescer at all.

JP9241695A (LION CORP, 1997) describes a process for making : high BD NTR powders in which a mixture containing a fluorescer, a non-ionic surfactant and water is added to pre-neutralized acid precursor of the anionic surfactant.

Such a mixing (solid/liquid) leads to relatively lower degree of uniformity in distribution of the fluorescer in the composition.

Yet another known process exists in which an aqueous solution of the fluorescer is mixed with un-neutralised

LABSA, (i.e. Linear Alkyl Benzene Sulphonic Acid, also known as LAS acid in the trade), which is heated in the range of 60 to 80 °C. The LABSA is then neutralised by addition of an alkali. The present inventors have observed that heating

LABSA to such a high temperature 1s an extremely energy intensive process and further, the degree of uniformity in the distribution of the fluorescer is relatively low.

Thus, it may be seen from the above prior art that there is a need for a process for making NTR detergent powder which ] includes a fluorescer; having relatively high degree of uniformity in the distribution of the fluorescer, while avoiding at least some of problems of the prior art.

OBJECT OF THE INVENTION

It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art. :

It is an object of the present invention to provide a process for making NTR detergent powder composition which includes a fluorescer, in which the degree of distribution ©f the fluorescer in the powder composition is relatively ; high, while avoiding at least some of problems of the prior ' art.

It 1s an object of the present invention to provide a process for making NTR detergent powder composition which includes a relatively lower amount of fluorescer, in which 5 the degree of distribution of the fluorescer in the powder composition is relatively high.

Other objects of the present invention will become apparent : to those skilled in the art by reference to the - 10 specification.

The present inventors have found that an NTR (Non-Tower

Route) detergent powder having relatively high degree of uniformity in the distribution of the fluorescer could be obtained when neutralisation of an acid precursor of an anionic surfactant is a carried out in presence of an aqueous solution or dispersion of a fluorescer, where temperature of the aqueous solution or dispersion is in the range of 60 to 80 °C.

SUMMARY OF THE INVENTION ]

According to the first aspect, the present invention ; provides a process for making a non-spray-dried detergent : composition comprising a step of neutralisation of an acid precursor of an anionic surfactant, in which, an aqueous : solution or dispersion of a fluorescer is mixed with the precursor, prior to neutralisation, wherein temperature of the aqueous solution or dispersion is in the range of 60 to 80 °C.

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According to the second aspect, the present invention provides a non-spray-dried detergent composition obtained by the process according to the first aspect.

The term “comprising” is meant not to be limiting to any subsequently stated elements but rather to encompass non- specified elements of major or minor functional importance.

In other words the listed steps, elements or options need : not be exhaustive. Whenever the words “including” or “having” are used, these terms are meant to be equivalent to “comprising” as defined above.

Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material ought to be understood as modified by the word “about”.

It should be noted that in specifying any range of concentration or amount, any particular upper concentration ; can be associated with any particular lower concentration or amount.

For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments. :

DETAILED DESCRIPTION OF THE INVENTION

The expression “weight%” wherever used in the specification : : means % by weight.

: According to the first aspect, the present invention provides a process for making a non-spray-dried detergent composition comprising a step of neutralisation of an acid precursor of an anionic surfactant, in which, an aqueous solution or dispersion of a fluorescer is mixed with the precursor, prior to neutralisation, wherein temperature of the aqueous solution or dispersion is in the range of 60 to 80 °C. :

It has been observed by the present inventors that when the aqueous solution or dispersion of the fluorescer is heated and mixed with the acid precursor of the anionic surfactant, prior to neutralisation; very high degree of uniformity in : the distribution of the fluorescer could be obtained.

Agitation of the aqueous solution or dispersion and of its mix with the acid precursor may be necessary in some cases : to avoid undesirable sedimentation. The aqueous solution or dispersion may contain non-ionic surfactant. Examples include C12-7EO. It is preferred for the fluorescer to be in aqueous solution. Any nonionic can be post-mixed with the solution before adding the mixture so formed to the acid precursor of the anionic surfactant. : :

Preferably, the concentration of the fluorescer in the ! aqueous solution or dispersion is in the range of 3 to 15 : weight%, more preferably in the range of 5 to 10 weighty, and most preferably in the range of 6 to 8 weight%. It is : preferred that the aqueous solution or dispersion is in the : range of 2 to 8 % by weight of the acid precursor of anionic ’ surfactant, more preferably in the range of 2 to 6 % by weight, and most preferably it is 3 % by weight. It is preferred that the rate of addition of the aqueous solution i or dispersion of the fluorescer to the acid precursor of the anionic surfactant is in the range of 1 to 5 kg per minute, preferably 2 kg per minute. It is preferred that an aqueous solution of the fluorescer is used, as this gives very high degree of uniformity in distribution of the fluorescer. As mentioned above the aqueous solution may be admixed with nonionic before addition to the anionic surfactant acid.

The expression aqueous solution is intended to cover such mixtures with nonionic. The ratio of water to nonionic is preferably greater than 1:1.

The fluorescer may be a fluorescer known in the art; and is preferably selected from Biphenyl compounds or Triazine ]

Stilbenes. Preferred Biphenyl compounds are Distyryl biphenyls, (abbreviated as DSBP). Suitable examples include

TINOPAL CBS-X™ ex. Ciba Geigy.

It has been found by the present inventors that the process according to the invention results in relatively high degree of distribution of the fluorescer in the detergent ] composition. As the process distributes the fluorescer with a high degree of uniformity, a relatively lower level of fluorescer can be used without compromising on the whiteness/brightness level of the composition. This helps in reducing the cost of the composition. It is preferred that in the non-spray-dried detergent composition, the fluorescer ; is in the range of 0.001 to 1 weight%, more preferably in the range of 0.005 to 0.5 weight%, and most preferably in the range of 0.01 to 0.4 weight%. Particularly preferred level is in the range of 0.01 to 0.05 weight%, based on the : total composition.

Without wishing to be bound by theory it is believed that the relatively higher degree of uniformity in the

BE oo 9 distribution of the fluorescer is obtained as liquid-liquid mixing is a highly effective form of mixing, and in the present invention the acid precursor of the anionic surfactant, which is a liquid is mixed with an aqueous solution or dispersion of the fluorescer.

It is preferred that the acid precursor of anionic surfactant is linear alkyl benzene sulphonic acid (generally abbreviated as LABSA). The alkyl chain length of the acid is preferably in the range of Cy-C;3. Preferably, neutralisation is carried out by an alkaline material selected from Sodium carbonate, Sodium hydroxide, Potassium carbonate, Potassium : hydroxide, Sodium bicarbonate or Potassium bicarbonate. It 1s preferred that Sodium carbonate (Soda ash) is used for neutralisation.

The neutralisation is carried out in a mixer. The mixer may suitably be selected from SIGMA™ mixer, PLOUGH SHARE™ mixer or FUKAE™ mixer. It is preferred that the mixer is a SIGMA™ mixer. The process is carried out at a temperature (inside the mixer) in the range of 20 to 80 °C, preferably in the : range of 40 to 70 °C, and more preferably in the range of 60 to 70 °C. The operational rpm (revolutions per minute) of : mixing arms of the mixer is preferably in the range of 20 to 40 rpm. ;

According to another aspect, the present invention provides a non-spray-dried detergent composition obtainable by the process according to the first aspect.

It is preferred that the non-spray-dried detergent composition includes 10 to 25 weight%, -more preferably 12 to

16 weight%, and further more preferably 12 to 15 weight% anionic surfactant. Apart from the acid precursor of the anionic surfactant, which eventually gets neutralised to form a salt thereof (anionic surfactant), the detergent composition of the present invention may also contain additional anionic surfactants. Anionic surfactants are well-known to those skilled in the art. Examples include alkylbenzene sulphonates, particularly linear alkylbenzene sulphonates having an alkyl chain length of C3-Cig; primary and secondary alkylsulphates, particularly Cg-C;3 primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.

Other surfactants which may be present in the granular detergent composition are cationic, non-ionic, amphoteric and zwitter-ionic surfactants, and mixtures thereof. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in "Surface-

Active Agents and Detergents", Volumes I and II, by

Schwartz, Perry and Berch. :

Non-ionic surfactants that may be used include the primary ; and secondary alcohol ethoxylates, especially the Cg-Cy aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol, and specially the C3-Cis primary and secondary aliphatic alcohols ethoxylated with an average of from 1 to 10 moles of ethylene oxide per mole of alcohol. Non-ethoxylated non- ' ionic surfactants include alkylpolyglycosides, glycerol monoethers, and polyhydroxyamides (glucamide). ;

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Cationic surfactants that may be used include quaternary ammonium salts of the general formula R;R;R3R,N'X™ herein the R groups are long or short hydrocarbyl chains, typically alkyl, hydroxyalkyl or ethoxylated alkyl groups, and X is a solubilising anion (for example, compounds in which R; is a

Cs-Cy2 alkyl group, preferably a Cg-Cip or Ci1-Cis alkyl group,

R, is a methyl group, and R; and R,, which may be the same or different, are methyl or hydroxyethyl groups); and cationic esters (for example, Choline esters).

The non-spray-dried detergent composition also preferably contains 20 to 70 weight%, more preferably 10 to 60 weight% detergency builder selected from Sodium tripolyphosphate,

Zeolite, or Sodium carbonate. Especially preferred organic builders are Carbonates, suitably used in amounts of from 20 to 60 weight%, preferably from 25 to 45 weight%. Sodium i carbonate may be used for neutralisation and/or may be post- : 70 dosed.

The non-spray-dried detergent composition preferably includes 20 to 50 weight% salt selected from Sodium chloride or Sodium sulphate.

The non-spray-dried detergent composition preferably includes 4 to 16 weight%, preferably 6 to 10 weight% flow aid selected from Calcite or Dolomite. A particularly preferred grade of Calcite is FORCAL-U™,

The non-spray-dried detergent composition may also suitably ! contain a bleach system. Preferably this will include a peroxy bleach compound, for example, an inorganic per-salt ; or an organic peroxy-acid, capable of yielding Hydrogen peroxide in aqueous solution. Preferred inorganic per-salts are sodium perborate monohydrate and tetrahydrate, and sodium percarbonate, the latter being especially preferred. :

The sodium percarbonate may have a protective coating against destabilisation by moisture. The peroxy bleach compound is suitably present in an amount of from 5 to 35 weight%, preferably from 10 to 25 weight%. The peroxy bleach compound may be used in conjunction with a bleach activator (bleach precursor) to improve bleaching action at low wash temperatures. The bleach precursor is suitably present in an amount of from 1 to 8 weight%, preferably from 2 to 5 weight%. Preferred bleach precursors are peroxycarboxylic acid precursors, more especially peracetic acid precursors and peroxybenzoic acid precursors; and peroxycarbonic acid precursors. An especially preferred bleach precursor ] suitable for use in the present invention is N,N,N,N’- tetracetyl ethylenediamine (TAED). A bleach stabiliser (heavy metal sequestrant) may also be present. Suitable bleach stabilisers include ethylenediamine tetraacetate (EDTA) , diethylenetriamine pentaacetate (DTPA) , ethylenediamine disuccinate (EDDS), and the polyphosphonates such as the DEQUESTS™, ethylenediamine tetramethylene phosphonate (EDTMP) and diethylenetriamine pentamethylene phosphate (DETPMP). Bleach ingredients are preferably post- dosed.

Sodium silicate may also be present. The amount of sodium silicate may suitably range from 0.1 to 5 weight%. Sodium silicate may also be post-dosed, for example, as granular sodium di-silicate, or as sodium carbonate/sodium silicate co-granules, for example, NABION™ 15 ex Rhodia Chimie.

Powder flow may be improved by the incorporation of a small amount of a powder structurant. Examples of powder structurants, some of which may play other roles in the formulation as previously indicated, include, for example, fatty acids (or fatty acid soaps), sugars, acrylate or acrylate/maleate polymers, sodium silicate, and dicarboxylic acids (for example, SOKALAN™ DCS ex BASF. One preferred powder structurant is fatty acid soap, suitably present in an amount of from 1 to 5 weight%.

Other materials that may be present in the non-spray-dried detergent composition include anti-redeposition agents such as cellulosic polymers; soil release agents; anti-dye- transfer agents; post-dosed fluorescers; inorganic salts such as sodium sulphate; enzymes (proteases, lipases, amylases, cellulases); dyes; coloured speckles; perfumes; and fabric conditioning compounds. These may be included in : one or both the components, if sufficiently robust, or alternatively post-dosed in the granular detergent composition, as is well known to those skilled in the art.

Bulk density (BD) of the non-spray-dried detergent composition is preferably in the range of 550 to 1000 kg/m’, more preferably in the range of 600 to 1000 kg/m®> and most preferably in the range of 700 to 950 kg/m.

It was observed by the present inventors that superior powder whiteness (i.e. lower 'b' value) could be obtained when a non-ionic surfactant, such as C12-7E0, is present in the aqueous solution or dispersion of the fluorescer.

Where a continuous process for making the non-spray-dried : detergent composition is to be employed; mixing and densification steps may be carried out simultaneously using a high speed mixer, suitable examples include a SHUGI™

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Granulator, a DRAIS™ K-TTP 80 Granulator or LODIGE™ CB30 recycler. The residence time in the mixing step is suitably about 5 to 30 seconds and the rate of mixing in the apparatus is suitably in the range of 100 to 2500 xrpm depending upon the degree of densification and the particle size required. The granulation step, if present, may be carried out using a lower speed mixer for example, the

DRAIS™ K-T 160 or the LODIGE™ KM300 mixer. The residence time in the granulation step is suitably in the range of 1 to 10 minutes and the rate of mixing in the apparatus is about 40 to 160 rpm.

Suitable mixers include the FUKAE™ range of mixers. Other materials may be added subsequently as desired. Residence time is selected according to the required degree of granulation for example 1 to 20 minutes. i

In accordance with a preferred aspect of the process according to the invention; part or whole of the Sodium tripoly phosphate (STPP), Sodium carbonate, Zeolite, Sodium chloride and Sodium sulphate is taken into a mixer ] (PSM™/FUKAE™/SIGMA™) . The fluorescer is then mixed in the required amount of water and then heated in the range of 60 to 80 °C to get a clear solution. Alternatively, the fluorescer may be added directly to the hot water (60 to 80 °C) to obtain the clear solution. This clear solution is then added to LABSA with continuous stirring to get a uniform mix of the fluorescer in the LABSA. Slight . temperature rise may happen during this mixing process which will facilitate mixing. Then this mix is added to the mixer already containing Sodium tripoly phosphate (STPP), Sodium carbonate, Zeolite, Sodium chloride and Sodium sulphate and oo ‘ 15 other minors and mixed for 2-3 minutes to ensure near- complete neutralization of LABSA. After LABSA neutralization is nearly complete, remaining part of the builders and salts “ is added into the mixer and mixed for about a minute. Then the other remaining minor ingredients are mixed to complete the base powder. This base powder can then be post-dosed in a Double Cone mixer or Drum mixer where perfumes, speckles, enzymes, and other minor ingredients, if any, are mixed to produce the finished powder.

Further details of the invention, its objects and advantages are explained hereunder in greater details with reference to the following non-limiting examples. It would be apparent to a person skilled in the art that many such examples are possible and the examples given under are for illustrative purpose only. These should not be construed so as to limit ; the scope of this invention in any manner.

EXAMPLES ] " EXAMPLE-1

Preparation of a non-spray-dried detergent composition by the process according to the invention

Approximately 1000 kg of an NTR detergent composition having the final formulation as given in Table-1 below was made by the process as described below. 335.9 kg of light soda ash and 466 kg of common salt were ; charged to a mixer. Half kg of the TINOPAL CBS-X ex. Ciba

Geigy, was mixed with 5 kg of water and the mixture was heated to 60 °C to get a clear transparent solution. This i

.. . 16 clear transparent solution was then added to 155.95 kg of

LABSA (Linear alkyl benzene sulphonic acid; 90% purity) with continuous stirring to get a uniform mix of the fluorescer § in LABSA. Then this LABSA containing the fluorescer was added to the mixer already containing the soda ash and salt and mixed for 2-3 minutes to ensure near-complete neutralization of LABSA. The rate of addition of LABSA was 55 kg per minute. The contents were thoroughly mixed for 3 to 4 minute, till the neutralisation neared completion.

Thereafter, 3.8 kg perfume was then mixed with the mass.

Finally, 45 kg Forcal-U™ was added. The contents were mixed for 30 seconds to get the finished product.

Table-1 —_—

Quantity/kg weight %

LABSA (90% 155.95 15.0 (in the form of Sodium purity) salt) 335.9

FORCAL-U™

TINOPAL 0.5 (dissolved in | 0.05

CBG -X™ 5 kg water) ]

Moisture + 5 3.5

NDOM* ] 1012.15 100.00

Note: *NDOM is non-detergent organic matter 1

EXAMPLE -2

In this example, a detergent composition containing 0.01 weight% TINOPAL CBS-X™ was made by making appropriate ] changes to the composition of Example-1. All other components were used at the same levels.

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In this example, a detergent composition containing 0.03 weight% fluorescer (TINOPAL CBS-X™) was made and also 0.9 weight% of non-ionic surfactant C12-7EO0 was included by nN making appropriate changes to the composition of Example-1.

All other components were used at the same levels.

Control Processes

Control-1

In this process, a detergent composition containing 0.05 weight% TINOPAL CBS-X™ was made by a conventional process in which the fluorescer was directly mixed with the acid precursor of the anionic surfactant, prior to ; neutralisation, and the rest of the process was as followed in Example-1.

Control-2

In this case, the fluorescer was pre-mixed with Sodium carbonate (Soda ash), which was used to neutralise the acid ; precursor of the anionic surfactant, as described in

JP11189799 A (LION CORP, 1999). The final level of the fluorescer in the composition was 0.02 weight%. The rest of : the process was as followed in Example-1.

Control-3 :

In this case, the fluorescer was mixed with non-ionic surfactant (Cl12-7EO) and this mix was sprayed onto the pre- neutralised anionic surfactant (LABSA) , as done in

JP9241695A. The final level of the fluorescer in the ‘ composition was 0.05 weight% and that of the non-ionic ) i

. 18 surfactant was 0.9 weight%. The rest of the process was as followed in Example-1.

Control-4

In this process, a detergent composition containing 0.05 weight% TINOPAL CBS-X™ was made by a conventional process in which solution of the fluorescer, which was at room temperature, i.e. 25 to 30 °C, was directly mixed with the acid precursor of the anionic surfactant, prior to neutralisation, and the rest of the process was as followed in Example-1.

Whiteness/Brightness of the detergent compositions :

The “Whiteness Index” and “F-value” of the compositions of ;

Example-1, 2 and 3 and that of the Control processes 1, 2 and 3 were determined by methods well known to the person skilled in the art. The results are provided in Table-2 below.

The measurements were carried out by using a spectrophotometer. “F” value was measured as the A460 and was ; measured as follows:

Delta R460 values are determined by measuring the reflectance of light from the sample at 460 nm when irradiated with a

Tungsten lamp without a filter and measuring the reflectance, of the sample with a “UV” filter and calculating the difference between the two measurements. This method provides an indication of the contribution of the fluorescer to the reflectance of the sample. The results of the Ganz Whiteness

Index and “F” values are reported in Table-2 below, which are average values of five measurements in each case. :

Table-2

Sample Whiteness SD* in F-Value SD* in ’

Index (WI) measuring measuring

WI F-Value 93.11 9.712 118.0

Control-1 | 77.80 6.492

Control-2

Control-3 113.15 - lmesz [=

Note: :

SD* stands for Standard Deviation

Ex stands for Example ]

The data in the above table indicates that the Whiteness 1

Index and the F-values of the compositions made by the process in accordance with the invention is significantly high as compared to the of the control processes. It may also be seen that the Standard Deviation in the observed values in the case of the non-spray-dried detergent compositions made by the process in accordance with the invention is comparatively significantly lower. This indicates a relatively high degree of uniformity in the distribution of 75 the fluorescer in the compositions made by the process in accordance with the invention.

It will be appreciated that the illustrated examples provide : a process for making NTR detergent powder which includes a } fluorescer, in which the degree of distribution of the fluorescer in the composition is relatively high; while avoiding at least some of problems of the prior art. :

It will be appreciated that the illustrated examples, provide a process for making NIR detergent powder composition which includes a relatively lower amount of : fluorescer, in which the degree of distribution of the fluorescer in the powder composition is relatively high.

It will be appreciated that the illustrated examples, provide for a process for making NTR detergent powder composition which includes a fluorescer, in which the degree of distribution of the fluorescer in the powder composition is relatively high, by using relatively lower amount of the fluorescer. 1S It should be understood that the specific forms of the invention herein illustrated and described are intended to be representative only as certain changes may be made therein without departing from the clear teachings of the disclosure. : :

Although the invention has been described with reference to ; specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (10)

CLAIMS:

1. A process for making a non-spray-dried detergent composition comprising a step of neutralization of an acid precursor of an anionic surfactant, in which, an aqueous solution or dispersion of a flourescer is mixed with said precursor, prior to neutralisation, wherein temperature of said aqueous solution or dispersion is in the range of 60 or 80°C.

2. A process as claimed in claim 1 wherein concentration of the fluorescer in said aqueous solution or dispersion is in the range of 3 to 15 weight %.

3. A process as claimed in claim 1 or 2 wherein said aqueous solution or dispersion is 2 to 8 % by weight of the said precursor of anionic surfactant.

: 4. A process as claimed in claim 1 wherein said acid precursor of anionic surfactant is linear alkyl benzene sulphonic acid. :

5. A process as claimed in claim 1 wherein said ] neutralisation is carried out by an alkaline material selected from Sodium or Potassium salt of carbonate, bicarbonate or hydroxide.

6. A process as claimed in claim 1 wherein rate of addition of the aqueous solution or dispersion of said ]

flourescer to said acid precursor of the anionic surfactant is in the range of 1 to 5 kg per minute.

7. A process as claimed in claim 1 wherein said flourescer is selected from Biphenyl compounds or Triazine Stilbenes.

8. A process as claimed in claim 1 wherein an aqueous solution of the flourescer 1s added to said acid precursor of the anionic surfactant.

9. A non-spray-dried detergent composition obtained by the process as claimed in claim 1.

10.A process substantially as hereindescribed with reference to the accompanying examples.