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

MANUFACTURE OF DETERGENT GRANULES BY DRY NEUTRALISATION

HINDUSTAN UNILEVER LIMITED, a company Incorporated under the Indian Companies Act, 1913 and having its registered office
at 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
MANUFACTURE OF DETERGENT GRANULES BY DRY NEUTRALISATION
5 This invention relates to the manufacture of detergent
granules by dry neutralisation, in particular to a process for the dry neutralisation of surfactant acid with Sodium Carbonate to form detergent granules comprising anionic non- soap surfactant.
10
BACKGROUND
Detergent granules are normally manufactured as agglomerates 15 of smaller particles. This agglomeration can be achieved by spray drying, mixing, or a combination of those processes. Many detergent granules comprise non-soap anionic surfactants, for example alkyl benzene sulphonate. Such granules have been prepared by in-situ neutralisation of the
20 acid precursor of the non-soap anionic surfactant, referred to hereafter as "surfactant acid" with a solid alkali salt, usually Sodium Carbonate.
GB 1 369 269 discloses a process for the neutralisation of
25 synthetic organic anionic detergent acids, such as straight chain alkyl benzene sulphonic acid, by mixing the acid with an excess of powdered Sodium Carbonate in a modified mixer with a cutting arrangement, for example a Lodige ploughshare mixer. A builder and/or filler salt is taught to be added
30 with the Sodium Carbonate in order to make the product more free flowing. The choppers or cutters in the mixer are used
' - 5 NOV 2009
during addition of the acid. Examples 1 and 2 include a sodium tripolyphosphates in the dry mix. The powders produced are free flowing. Example 3 uses no sodium tripolyphosphate but the product requires pulverisation and
5 is not described as free flowing. A problem with this
disclosure is that it is now desirable to exclude phosphate from the granule, but this document does not teach an effective process for its elimination.
10 GB 2 221 695 describes a dry neutralisation process for
preparation of detergent powder of high bulk density in a high speed mixer granulator, with a stirring and a cutting action. In most of the examples, zeolite or Sodium Tripolyphosphate is used in addition to Sodium Carbonate.
15 In examples 26 to 29, very high levels of Sodium Carbonate are used and a special calcite flow aid is dosed at 4% to assist with the granulation. Despite this, the flow properties of example 26 are very poor and addition of Sodium Tripolyphosphate is taught as a remedy for this
20 problem. A problem with this process is that the use of a flow aid is a major process complication and it is now desirable to exclude phosphate from the granule.
WO 2002/24854 describes a dry neutralisation process carried 25 out in a horizontal thin-film evaporator drier. Use of
small particle size Sodium Carbonate is taught to reduce the amount of unneutralised surfactant acid in the resulting product. Such unneutralised material is known to be undesirable as it continues to react with the Sodium
30 Carbonate and causes powder caking. In the examples,
zeolite is also added. This addition would reduce the level
of anionic surfactant in the detergent granule. Furthermore, it is now desirable to be able to eliminate use of zeolite from a detergent granule if it is not essential in the formulation.
5
US 7 053 038 describes a dry neutralisation process carried out in a gas fluidisation granulator using small particle size Sodium Carbonate and an inorganic acid, such as sulphuric acid. Both zeolite and sodium tripolyphosphate
10 are included in all the examples.
EP 1 534 912 discloses dry neutralisation of preformed spray dried particles comprising a carbonate salt and polyacrylate. The process is carried out under low shear
15 conditions in order to avoid agglomeration. In all of the examples, the carbonate salt is the Burkeite double salt formed when Sodium Carbonate and sodium sulphate are spray dried together. These particles are too strong to be used in the process of the present invention. As further
20 explained later this process does not make habit modified Sodium Carbonate.
EP 0 221 776 describes a process to spray dry Sodium Carbonate and a crystal growth modifier to make, so called, 25 habit modified carbonate granules. The crystal growth modifier is preferably polymeric polycarboxylate. The patent describes the manufacture of habit modified Burkeite in the majority of the examples. Only example 1 crystal habit modifies Sodium Carbonate itself.
Habit modified Sodium Carbonate is also spray dried for use as a carrier granule in WO 2006/081930. Polyaspartates are used in place of the polycarboxylates of EP 0 221 776.
5 Throughout this specification habit modified Sodium Carbonate is a term used to encompass such prior art materials. The term does not include habit modified Burkeite, although low concentrations of Burkeite could conceivably be included in admixture with the desired habit
10 modified Sodium Carbonate provided that the resulting admixture remains characterised as described below.
There remains a need for a process to manufacture detergent granules by dry neutralisation, that does not require the
15 use of additives such as zeolite, Sodium Tripolyphosphate, or flow aids to facilitate satisfactory granulation and at the same time provides the required conversion of surfactant acid to surfactant.
20 It is an object of the present invention to provide an
improved process for the manufacture of detergent granules comprising non-soap anionic surfactant by dry neutralisation. It is also an object to provide detergent granules comprising Sodium Carbonate and exceptionally high
25 levels of non-soap anionic surfactant, which exhibit improved storage and handling properties.
SUMMARY OF THE INVENTION
30 According to the present invention there is provided a
process for the manufacture of detergent granules comprising
anionic non-soap surfactant, the process comprising the step of dry neutralisation of surfactant acid with habit modified Sodium Carbonate, which is a crystal growth modified Sodium Carbonate that comprises a mixture of Sodium Carbonate and
polymer.
5 The invention also provides detergent granules comprising at least 30 wt% anionic surfactant comprising a major part of anionic non-soap surfactant and habit modified Sodium
10 Carbonate, which is a crystal growth modified Sodium
Carbonate that comprises a mixture of Sodium Carbonate and polymer, and less than 10 wt%, preferably zero, zeolite, obtainable by the process.
15
DETAILED DESCRIPTION OF THE INVENTION
The habit modified Sodium Carbonate (HMC)
20 Habit modified Sodium Carbonate is a crystal growth modified Sodium Carbonate, which comprises a mixture of Sodium Carbonate and polymer. Its manufacture is, for example, described in EP 0 221 776 and WO 2006/081930. It is not the same thing as habit modified Burkeite; the double salt of
25 Sodium Carbonate and Sodium Sulphate.
It is essential that the polymer used as crystal growth modifier is present when crystallisation of the habit modified Sodium Carbonate occurs, that is to say, it must be
30 incorporated not later than the Sodium Carbonate.
Habit modified Sodium Carbonate is further characterised by its specific surface area, measured by nitrogen adsorption. The specific surface area ("SSA")of the Sodium Carbonate is measured by nitrogen absorption according to ASTM D 36 63-78
5 standard based upon the Brunauer, Emmett, and Teller (BET) method described in J. Am. Chem. Soc. 60, 309 (1938). We used a Gemini Model 2360 surface area analyzer (available from Micromeritics Instrument Corp. of Norcross, Ga.). The Habit modified Sodium Carbonate is characterised by
10 having a specific surface area (SSA) of 5 m2/g or greater,
preferably 8 m2/g or greater, even more preferably 10 m2/g or greater.
The pore volume in pores less than 2 micron may further
15 characterise the habit modified Sodium carbonate. This is
measured by a conventional mercury porosimetry method. Pore volumes of 0.3 ml/g or greater are advantageous.
An alternative characterisation of the habit modified Sodium 20 Carbonate, comprising polymer and Sodium Carbonate, is to
use it in the process of claim 1 with sulphonic acid and to determine the maximum Sodium Sulphonate anionic non-soap surfactant levels achievable before over-granulation occurs. Over-granulation means that the discrete detergent granules
25 begin to coalesce into a sticky mass and it is no longer
possible to discharge them as a free flowing product without adding flow aid or other solid materials such as Zeolite or Sodium Tripolyphosphate. If the anionic Sodium Sulphonate surfactant level achieved is greater than 30 wt%, preferably 30 greater than 35 wt%, more preferably greater than 45 wt%,
then the Sodium Carbonate is habit modified for the purpose of this invention.
Habit modified Sodium Carbonate, herein also referred to as
5 HMC, may be made by spray drying, as described in EP 0 221 776 and WO 2006/081930. Alternative drying methods, as described in those patent applications, may also be employed: for example, air drying, oven drying, drum drying ring drying, freeze drying, solvent drying, or microwave
10 drying.
HMC can also be made by precipitation of a saturated Sodium Carbonate solution, which further comprises a growth modifying polymer, in an evaporator, separating the
15 precipitate; e.g. by filtration and drying the precipitate to habit modified Sodium Carbonate. The remaining solution is augmented with fresh Sodium Carbonate solution and polymer solution and returned to the evaporator. The advantage of a precipitation process over one that relies
20 entirely on drying is that energy consumption is lower.
The polymer
25 An essential component of habit modified Sodium Carbonate i the polymer. Suitable crystal growth modifying polymers ma be selected from polycarboxylates. Polyaspartates and polyaspartic acid are advantageously used due to their biodegradability.
Preferred polymeric polycarboxylate crystal growth modifiers used in the invention are used in amounts of from 0.1 to 20 wt%, preferably from 0.2 to 5 wt%, most preferably 1 to 5 wt%, based on the total amount of Sodium Carbonate.
5 However, higher levels of polymer, for example, up to 60% by weight based on Sodium Carbonate, may be present in detergent granules of the invention, or full compositions comprising the detergent granules of the invention, for reasons other than crystal growth modification, for example, 10 building, structuring or antiredeposition.
The polycarboxylate crystal growth modifier preferably has a molecular weight of at least 1000, advantageously from 1000 to 300 000, especially from 1000 to 250 000.
15 Polycarboxylate crystal growth modifiers having molecular
weights in the 3000 to 100 000 range, especially 3500 to 70 000 and more especially 10 000 to 70 000 are preferred. All molecular weights quoted herein are those provided by the manufacturers.
20
Preferred crystal growth modifiers are homopolymers and copolymers of acrylic acid or maleic acid. Of especial interest are polyacrylates and acrylic acid/maleic acid copolymers.
25
Suitable polymers, which may be used alone or in combination, include the following:
Salts of polyacrylic acid such as sodium polyacrylate, for
30 example Versicol (Trade Mark) E5 E7 and E9 ex Allied
Colloids, average molecular weights 3500, 27 000 and 70 000;
Narlex (Trade Mark) LD 30 and 34 ex National Adhesives and Resins Ltd, average molecular weights 5000 and 25 000 respectively; and Sokalan (Trade Mark) PA range ex BASF, average molecular weight 250 000; ethylene/maleic acid
5 copolymers, for example, the EMA (Trade Mark) series ex Monsanto; methyl vinyl ether/maleic acid copolymers, for example Gantrez (Trade Mark) AN119 ex GAF Corporation; acrylic acid/maleic acid copolymers, for example, Sokalan (Trade Mark) CP5 ex BASF.
10
A second group of polymeric crystal growth modifiers comprises polyaspartic acids and polyaspartates.
Preferred polymeric crystal growth modifiers in this second 15 group have a molecular weight of at least 1000,
advantageously from 3500 to 300000, especially from 4000 to 250000. HMC is preferably prepared using polyaspartate crystal growth modifiers having molecular weights in the 3500 to 100000 range, especially 4000 to 70000 and more 20 especially 5000 to 70000. All molecular weights quoted herein are those provided by the manufacturers.
Polyaspartate is a biopolymer synthesised from L-aspartic acid, a natural amino acid. Due in part to the carboxylate 5 groups, polyaspartate has similar properties to
polyacrylate. One preferred type of polyaspartate is thermal polyaspartate or TPA. This has the benefit of being biodegradable to environmentally benign products, such as carbon dioxide and water, which avoids the need for removal
30 of TPA during sewage treatment, and its disposal to landfill.
TPA may be made by first heating aspartic acid to temperatures above 180°C to produce polysuccinimide. Then the polysuccinimide is ring opened to form polyaspartate.
5 Because the ring can open in two possible ways, two polymer linkages are observed, an [alpha]-linkage and a [beta]- linkage.
Amounts of from 0.1 to 20 wt% of the crystal growt
10 modifier, preferably from 0.2 to 5 wt%, most preferably 1 to 5 wt%, based on the total amount of Sodium Carbonate are generally sufficient to produce suitable habit modified Sodium Carbonate.
15 Mixtures of any two or more polymeric crystal growth modifiers may, if desired, be used in the process and detergent granule compositions of the invention.
20 The Sodium Carbonate
The Sodium Carbonate used to make the habit modified Sodium Carbonate may be of any type. Synthetic light soda ash has been found to be especially preferred; natural heavy soda
25 ash is intermediate, while synthetic granular soda ash is the least preferred raw material.
The surfactant acid
The surfactant acid is an acid precursor of an anionic non- soap surfactant which, when reacted with habit modified Sodium Carbonate will be neutralised to form the sodium salt of the anionic surfactant. Surfactant acids in liquid,
5 pumpable, form are preferred.
A preferred class of anionic surfactants is alkyl aryl sulphonates. The preferred surfactant acid is linear alkyl benzene sulphonic acid, also referred to as LAS acid and
10 HLAS. This surfactant acid gives a corresponding linear alkyl benzene sulphonate (LAS) upon neutralisation. Preferably, the LAS non-soap anionic surfactant has an alkyl chain length of C8-18, more preferably C10-16 and most preferably C12-14.
15
A second preferred class of anionic surfactant is the alkyl and/or alkenyl sulphuric acid half-esters (i.e. the sulphation products of primary alcohols) which give alkyl and/or alkenyl sulphates upon neutralisation. Among such
20 non-soap anionic surfactants is primary alcohol sulphate (PAS), especially PAS having a chain length of C10-22, preferably C12-14; Coco PAS is particularly desirable.
Other suitable surfactant acids include alpha-olefin
25 sulphonic acids, internal olefin sulphonic acids, fatty acid ester sulphonic acids and primary sulphonic acids.
It is also possible to use combinations of surfactant acids as will be apparent to the skilled person.
Soaps formed by the dry neutralisation of carboxylic or fatty acids may be used as secondary anionic surfactants in admixture with the non-soap anionic surfactants. Preferred carboxylic acids are fatty acids with 12-18 carbon atoms,
5 such as for example fatty acids of coconut oil, palm oil,
palm kernel and tallow. The fatty acids may be saturated or unsaturated, branched or straight chain. Mixtures of fatty acids may be used. Fatty acids may be used at levels of up to 30 wt% based on the surfactant acid.
10
The surfactant acid (or mixture of surfactant acids) may be used in a partially pre-neutralised form without loss of the advantageous effects of the invention. In effect, the surfactant acid is then a mixture of the surfactant acid
15 with neutralised anionic non-soap surfactant.
Optional further ingredients present during the process
The HMC dry neutralisation process has all of the advantages 20 and flexibility of prior art dry neutralisation processes.
The surfactant acid may be added in admixture with other liquid components. Among these, in addition to the fatty acids and neutralised anionic surfactant already discussed,
25 the most important additional component that may be added as liquids with the surfactant acid is nonionic surfactant. This is typically added to the surfactant acid to reduce viscosity to enable it to be added at a lower temperature.
30 Suitable nonionic surfactants that may be used include the primary and secondary alcohol ethoxylates, especially the
C8-C2 0 aliphatic alcohols ethoxylated with an average of from 1 to 50, preferably 1 to 20, moles ethylene oxide per mole of alcohol, and more especially th£ do-cis primary and secondary aliphatic alcohols ethoxylated with an average of 5 from 1 to 10 moles of ethylene oxide pef mole of alcohol. Non-ethoxylated nonionic surfactants include alkylpolyglycosides, glycerol monoether, and polyhydroxyamides (glucamide). As discussed already neutralised anionic surfactant may be mixed with the
10 surfactant acid. This can have the advantage of increasing throughput of the reaction vessel/mixer.
Other liquid additives that may be added with the anionic surfactant acid, or added as separate liquid stream(s),
15 include inorganic acids, such as sulphuric acid, and hydrotropes, such as para toluene sulphonic acid.
A small amount of water, sufficient to initiate the neutralisation reaction but not sufficient to cause
20 substantial agglomeration, may be premised with the
surfactant acid before the latter is introduced into the mixer, but addition of water is not essential. If a coloured product is desired, dyestuff may conveniently be premixed with the surfactant acid and water before addition
25 to the mixer. The amount of water to be added may up to about 2 wt% based on the total granule ingredients.
Additional solid may be admixed with the habit modified Sodium Carbonate. This can be done either before or during
30 neutralisation of the surfactant acid. Unmodified Sodium
Carbonate, i.e. soda ash, may be used in admixture with the
habit modified Sodium Carbonate. Zeolite and/or other builder materials could be added, although they are not needed to gain the good granule properties ascribed to the use of HMC. It is preferred to avoid use of zeolite
5 completely, except perhaps as a final whitening coating. A complete detergent system can nevertheless be formulated into a single simple dry neutralised granule especially when Calcium tolerant surfactant blends are used. Calcium tolerant surfactant blends are those single or mixed
10 surfactants, which do not require builders to be present for effective detergency across a normal range of water hardness. We use the following method to test a surfactant blend for Calcium-tolerance. First 0.7 g/L of the surfactant blend are dissolved in water containing
15 sufficient Calcium ions to give a French hardness of 40 (4 x 10~3 Molar Ca2+) . Other electrolytes such as Sodium Chloride, Sodium Sulphate, and Sodium hydroxide are then added as necessary to adjust the ionic strength to 0.05M and the pH to 10. The adsorption of light of wavelength 540 nm through
20 4 mm of sample is measured 15 minutes after sample
preparation. Ten measurements are made and an average value is calculated. Calcium tolerant blends are those that give an average value of less than 0.08.
25 Calcium tolerant surfactant blends that may be dry
neutralised include mixtures of LAS with nonionic high EO, SLES paste and/or AOS paste.
In addition to the essential habit modified Sodium
30 Carbonate, conventional builders and non habit modified
Sodium Carbonate may also be added to the mixer. Examples of
' - 5 NOV 2009
• •
such builders include crystalline and amorphous alkali metal aluminosilicates, alkali metal phosphates, and mixtures thereof. The total of habit modified Sodium Carbonate and Sodium Carbonate should always be present in excess of the
5 amount required for neutralisation, in order to provide
alkalinity in the product: an excess of about 10 to 15 wt% is then suitable. This represents a molar excess of 3:1 or more.
10 The solids present in the mixer may also include other solid ingredients desired for inclusion in the detergent granule, for example, fluorescers; polycarboxylate polymers; antiredeposition agents, for example, sodium carboxymethyl cellulose; or fillers such as sodium sulphate, diatomaceous 15 earth, calcite, kaolin or bentonite.
If desired, solid particulate surfactants, for example, alkylbenzene sulphonate and/or alkyl sulphate in powder form, may form part of the solids charge to the mixer to
20 further increase the activity level of surfactant in the
granule, however it is preferred to produce all the anionic surfactant by dry neutralisation.
Other anionic surfactants that may be present in detergent
25 granules prepared by the process of the invention include secondary alkyl sulphates, alkyl ether sulphates, and dialkyl sulphosuccinates. Anionic surfactants are of course well known and the skilled reader will be able to add to this list.
The dry neutralisation process
The surfactant acid is preferably used in liquid form and advantageously it is reacted while mixing with a molar
5 excess of habit modified Sodium Carbonate to form a sodium salt of the anionic surfactant, while mixing. As an alternative to use of a molar excess of habit modified Sodium Carbonate the reaction may be done with a mixture of habit modified Sodium Carbonate and a smaller amount of
10 other conventional Sodium Carbonate, such as light ash and/or Burkeite, with a corresponding reduction in the granulation benefits of the invention. Nevertheless, if large amounts of Sodium Carbonate are to be used this hybrid process reduces the amount of specially habit modified raw
15 material needed.
A wider than normal range of ratios of liquid to solid ingredients may be used in the dry neutralisation reaction. Because the system is self structuring, no zeolite or
20 similar structurant is needed and the process is easy to control.
The total amount of free water that can be tolerated in the process preferably should not amount to more than 8 wt% of
25 the total composition, preferably not more than 4 wt%.
When habit modified Sodium Carbonate is used in the dry neutralisation process then the resulting granule will comprise neutralised anionic surfactant together with any
30 excess habit modified Sodium Carbonate. The habit modified Sodium Carbonate is an excellent substrate for additional
liquid components and it also functions in the same way as Sodium Carbonate as a buffer in a detergent composition. The invention may thus advantageously be used to prepare detergent powders in which Sodium Carbonate is used without
5 any other builder present - especially if a Calcium tolerant surfactant blend or mixture is used. To ensure the presence of significant quantities of Sodium Carbonate in the granule substantially more habit modified Sodium Carbonate than is required for neutralisation may be present.
10
A process feature known to the person skilled in the art of dry neutralisation is that the surfactant acid should be added to the mixer sufficiently gradually so that it will be consumed immediately and will not accumulate in the mixer in 15 unreacted form. We have found that this applies equally to the process using habit modified Sodium Carbonate. The time required and preferred for addition of the surfactant acid is of course dependent on the amount to be added, but in general addition preferably takes place over a period of at
20 least 1 minute, more preferably over a period of from 2 to 12 minutes, most preferably from 3 to 10 minutes.
The mixer
25
The process is generally not sensitive to the type of mixer used, provided intensive mixing is applied. We have found that to obtain the full advantages of the invention the use of a mixer with a chopping action is advantageous. The HMC
30 starting material has a relatively low crush strength and the mixer should be selected so that it breaks up and
rapidly provides fine, material with a consequent large total surface area for reaction and for regranulation. Thus, a conventional fluid bed granulator would not be preferred for the dry neutralisation process using habit
5 modified carbonate.
Preferably, the mixing is carried out in a mixer having and using both a stirring action and a cutting action, most preferably these actions will be separately usable, as
10 described below. The cutting action is the preferred
chopping action. This may be advantageously achieved by the choice of mixer to be a high-speed mixer/granulator having both a stirring action and a cutting action. Preferably, the high-speed mixer/granulator has rotatable stirrer and
15 cutter elements that can be operated independently of one another, and at separately changeable or variable speeds. Such a mixer is capable of combining a high-energy stirring input with a cutting action, but can also be used to provide other, gentler stirring regimes with or without the cutter
20 in operation. The cutters would be off during the solids pre-mixing.
A Lodige mixer is preferred, vertical or horizontal axis cutters are desirable for high anionic loading. Also
25 preferred are mixers of the Fukae FS-G type manufactured by Fukae Powtech Co Ltd., Japan; this apparatus is essentially in the form of a bowl-shaped vessel accessible via a top port, provided near its base with a stirrer having a substantially vertical axis, and a cutter positioned on a 30 side wall.
The stirrer and cutter may be operated independently of one another, and separately variable speeds. The vessel can be cooled.
5 Other mixers believed to be suitable for use in the process of the invention are the Fuji (Trade Mark) VG-C series ex Fuji Sangyo Co., Japan; and the Roto (Trade Mark) ex Zanchetta & Co srl, Italy.
10 Yet another mixer found to be suitable for use in the process of the invention is the L6dige (Trade Mark) FM series batch mixer ex Morton Machine Co. Ltd., Scotland. This differs from the mixers mentioned above in that its stirrer has a horizontal axis. Z blade and sigma mixers
15 (Winkworth machinery limited) are suitable mixers having a chopping action.
The temperature of the powder mass in the mixer should be maintained throughout at 55 °C or below, preferably below 50
20 °C, more preferably below 47 °C, and desirably below 40 °C. If the temperature is allowed to rise too much, agglomeration and lump formation may occur.
25 The detergent granule
The granular product of the process is a particulate solid with a bulk density in the range 450 to 720 g/litre. The particle size distribution is generally such that at least 30 50 wt%, preferably at least 70 wt% and more preferably at least 85 wt%, of particles are smaller than 1700 microns, and the level of fines is low. No further treatment has
generally been found to be necessary to remove either oversize particles or fines.
The product generally has excellent flow properties, low 5 compressibility and little tendency towards caking.
The particulate detergent granules that are the direct result of the dry neutralisation process may have an anionic surfactant content of 25 wt% to 45 wt%, or even higher. The absence of the need for a granulation aid such as zeolite,
10 together with the ease that the reaction can be driven results in the potential to achieve exceptionally high levels of anionic surfactant in the granule. For example, greater than about 30 wt%, preferably greater than 35 wt%, even greater than 40 wt%, or over 45 wt% anionic surfactant
15 may be incorporated into the detergent granule. It is
preferred for the anionic surfactant to comprise less than 10 wt% soap, based on the total anionic surfactant in the detergent granule.
20 The detergent granules may also comprise water in an amount of 0 to 8% and preferably 0 to 4% by weight of the granules.
The detergent granules obtained from the process are storage stable at high levels of humidity. Thus, they can be used
25 in a wide range of detergent products.
Desirably the detergent granules have an aspect ratio not in excess of two and more preferably are generally spherical in order to reduce segregation from other particles in a
30 formulated powder detergent composition and to enhance the visual appearance of the powder.
Further processing
If desired, further ingredients may be admixed to the 5 detergent granules after they have been manufactured.
The detergent granules may be admixed with anything normally used in detergent formulations. They may be dry blended with solid materials and they may advantageously have further liquids added into them, using their spare liquid
10 carrying capacity. It is especially advantageous to add conventional, or even higher than conventional, levels of perfume this way.
Other types of non-soap surfactant, for example, cationic,
15 zwitterionic, amphoteric or semipolar surfactants, may also be used with the granules if desired. 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
20 and Berch.
Soap may also be present, to provide foam control and additional detergency and builder power. The fully formulated composition may comprise up to 8 wt% soap.
25
Detergent compositions including the detergent granules prepared by the process of the invention may contain conventional amounts of other detergent ingredients, for example, bleaches, enzymes, lather boosters or lather
30 controllers as appropriate, antiredeposition agents such as cellulosic polymers; anti incrustation agents, perfumes,
' -5 NOV 2QQ9 *
dyes, shading dyes, fluorescers, sodium silicate; corrosion inhibitors including silicates; inorganic salts such as sodium sulphate, enzymes; coloured speckles; foam controllers; and fabric softening compounds. The detergent
5 granule may if desired be mixed with other organic or inorganic builders, typically supplied in the form of granules of either pure builder or mixtures of builder and other ingredients. Especially preferred organic builders are acrylic polymers, more especially acrylic/maleic
10 copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10wt%. Such polymers may also fulfil the function of the habit modifying polymer.
The skilled detergent formulator can decide which
15 ingredients are suitable for admixture in the mixer, and which are not.
The detergent granules may be mixed with another powder obtained from any conventional detergent production process
20 including spray drying or non spray drying processes. For convenience, such other powder is hereinafter called a base powder. As the detergent granules produced by the present invention may be admixed with such other powders, a significant degree of formulation flexibility is obtained
25 and the level of active material in the fully formulated
•composition may be very high without an unnecessary increase in builder levels.
The total amount of surfactant present in the detergent 30 composition is suitably from to 5 to 40 wt%, although amounts outside this range may be employed as desired.
The detergent granules may typically constitute from 30 to 100 wt% of a final fully formulated detergent composition. Typically, the fully formulated detergent composition
5 incorporating the detergent granules produced by the process of the invention may comprise from 5 to 45 wt%, preferably 10 to 35 wt% of anionic surfactant, this anionic surfactant being derived wholly or in part from the granular product of the dry neutralisation.reaction. The process of the
10 invention is of especial interest for the production of
detergent powders or components containing relatively high levels of anionic surfactant, for example, 15 to 30 wt%, more especially 20 to 30 wt%. In addition, the fully formulated detergent composition may comprise from 0 to 10
15 wt% of nonionic surfactant, and from 0 to 5 wt% of fatty acid soap.
Fully formulated detergent compositions, comprising other ingredients and the detergent granules produced by dry
20 neutralisation of habit modified Sodium Carbonate;
preferably have a bulk density of at least 400 g/1, more preferably at least 450 g/litre.
The invention will now be further described with reference
25 to the following non limiting examples. In the examples, in addition to the SSA, pore volume and loading tests described above, the detergent granule properties are measured according to the following known test protocols.
30 Dynamic flow rate (DFR)
' - 5 NOV 20091' • i
This is also called flow-rate. Powder flow may be quantified by means of the dynamic flow rate (DFR), in ml/s, measured by means of the following procedure. The apparatus used consists of a cylindrical glass tube having an internal
5 diameter of 35 mm and a length of 600 mm. The tube is
securely clamped in a position such that its longitudinal axis is vertical. Its lower end is terminated by means of a smooth cone of polyvinyl chloride having an internal angle of 15° and a lower outlet orifice of diameter 22.5 mm. A
10 first beam sensor is positioned 150 mm above the outlet, and a second beam sensor is positioned 250 mm above the first sensor.
To determine the dynamic flow rate of a powder sample, the 15 outlet orifice is temporarily closed, for example, by
covering with a piece of card, and powder is poured through a funnel into the top of the cylinder until the powder level is about 10 cm higher than the upper sensor; a spacer between the funnel and the tube ensures that filling is
20 uniform. The outlet is then opened and the time t (seconds) taken for the powder level to fall from the upper sensor to the lower sensor is measured electronically. The measurement is normally repeated two or three times 'and an average value taken. If V is the volume (ml) of the tube
25 between the upper and lower sensors, the dynamic flow rate DFR (ml/s) is given by the following equation:
DFR = v/t ml/s t
30 Unconfined Compression Test (UCT)
In this test, freshly produced powder is compressed into a compact and the force required to break the compact is measured. The powder is loaded into a cylinder and the surface levelled. A 50 g plastic disc is placed on top of
5 the powder and a 10 kg weighted plunger is placed slowly on top of the disc and allowed to remain in position for 2 minutes. The weight and plunger are th£n removed and the cylinder removed carefully from the powder to leave a freestanding cylinder of powder with the 50tJ plastic disc on top
10 of it. If the compact is unbroken, a second 50 g plastic disc is placed on top of the first and left for approximately ten seconds. Then if the compact is still unbroken a 100 g disc is added to the plastic discs and left for ten seconds. The weight is then increased in 0.25 kg
15 increments at 10 second intervals until the compact
collapses. The total weight (w) needed to effect collapse is noted.
The cohesiveness of a powder is classified by the weight (w) as follows:
20 w < 1.0 kg Good flowing
1.0 kg < w < 2.0 kg Moderate flowing.
2.0 kg < w < 5.0 kg Cohesive.
5.0 kg < w Very cohesive.
25 Dissolution time (T90)
A 1-litre beaker is filled with 500mls of demineralised water at 20-25°C and stirred with a magnetic stirrer
*
adjusted to give a vortex of about 4cm. A sample of powder is added to the water. The dissolution is measured according to solution conductivity. The "T90' value is the time taken to achieve 90% of the final conductivity value.
5 Bulk density (BP)
This is measured by taking the increase in weight of a 1 litre container when it is filled with detergent granules and tapped lightly.
10 EXAMPLES
Sodium carbonate materials for use in dry neutralisation were obtained. Dense granulated sodium carbonate (reference carbonate A) and light soda ash (reference carbonate B) were
15 sourced directly from Brunner Mond. Reference carbonate C and HMC 1 to 6 were manufactured as described below.
HMC 1 ~ Spray dried HMC (low moisture)
HMC was prepared according to WO 2006/081930 Al by mixing
20 together 29.8 kg of Sokalan CP5 solution (40% active
material) with 1373.8kg of water in a stirred tank. Into this solution was then dissolved 596.4 kg of light Sodium Carbonate (ex Brunner Mond). The resultant solution was then spray dried in a 2.5 m diameter spray-drying tower to a
25 final product moisture content of 1.8 % (by IR Balance).
HMC 2 - Spray dried HMC (high moisture)
The preparation was as for HMC 1 except that the HMC was spray dried to a final product moisture content of 12.9 %
30 (by IR Balance).
HMC 3 - Oven dried HMC
0.06kg of Sokalan CP5 solution (40% active material) was mixed with 2.74 kg of water in a stirred tank. Into this solution was then dissolved 1.2 kg of light Sodium Carbonate 5 (ex Brunner Mond). The resultant solution was then dried in shallow trays (solution depth approximately 0.5cm) in an oven at 85°C.
HMC 4 - Drum dried HMC
10 A solution with composition by weight, 69.58% water, 0.6% Sokalan CPS (100% active material) and 29.82% light Sodium Carbonate (ex Brunner Mond) was dried using a 0.391m diameter twin-drum dryer (drying time of 25.6 seconds, drum temperature 148°C).
15
HMC 5 - Microwave dried HMC
1.5 g of Sokalan CPS solution (40% active material) was mixed with 68.5 g of water in a beaker. Into this solution was then dissolved 30g of light Sodium Carbonate (ex Brunner
20 Mond). The resultant solution was then dried in shallow trays (solution depth approximately 0.5cm) in a microwave oven (Samsung MX35 1000W).
HMC 6 - Precipitated HMC
25 29.8 g of Sokalan CP5 solution was dissolved in 1400 g of demin. water in glass beaker. To this solution was added 590g of light Sodium Carbonate (ex Brunner Mond). The resultant solution was then heated to 70°C with constant stirring and left open to atmosphere to allow evaporation.
30 Heating and stirring were continued until the solution
volume had reduced to approximately half its initial volume.
The resultant slurry was filtered to remove the crystals precipitated during evaporation. These crystals were then oven dried at 85°C to produce the final product.
5
Reference Carbonate C - Spray dried modified Burkeite 425.2kg of water was added to a lm3 mixing vessel having agitation impellers. To the water were sequentially added 25.3kg of sodium polyacrylate solution {Sokalan PA40 ex
10 BASF) followed by 330kg of Sodium Sulphate. The temperature of the mixture was then raised to 60°C and agitated for 8 minutes. 123.7 kg of Sodium Carbonate {Light ash ex Brunner Mond) was then added whilst maintaining agitation to form a slurry. The temperature of the resultant mixture was then
15 raised to 82°C and agitated for a further 12 minutes.
54.9kg of alkaline silicate solution {Crystal 112 ex Ineos Silicas) was then added. The resultant 53 wt% slurry was spray-dried to form a Burkeite carrier material similar to that made in the examples of EP 1 534 812 (Kao).
20
The above prepared samples had their specific surface area (SSA) and porosity in small pores {<2 micron diameter) measured using the BET method already described. In addition, by dry neutralisation experiments the maximum
25 amount of LAS acid (HLAS) surfactant acid that could be used with the different types of Sodium Carbonate was determined.
In Table 1 the SSA, porosity and HLAS capacity is summarised for carbonate materials used. It can be seen that there is
30 a correlation between SSA and the amount of surfactant acid.
Table 1
Carbonate Example pore vol
ml/g (diameter <2 micron) SSA(mVg) IAS Capacity (gHLAS /100g carrier)
Dense Ash Ref A 0. 07 0.46 9.4
Light Ash Ref B 0.21 1. 00 22. 5*
Burkeite Ref C 0.48 3.08 10.0
Spray Dried HMC HMC 1 0. 64 8.17 98 . 3
Drum Dried HMC HMC 4 0.78 8 . 69 80.7
Microwave HMC HMC 5 0.72 8 .88 122. 0
Oven Dried HMC HMC 3 0. 78 10.86 157. 5
Precipitated HMC HMC 6 0.77 12 .36 135.0

5
*granulation was not possible. The product was a sticky mess, so the amount of surfactant acid noted here is not a true granule carrying capacity.
10 Throughout the examples the surfactant acid used is LAS
acid: C9 to Cll Linear Alkyl Benzene Sulphonic Acid having a mean molecular weight of 320 a purity of 97% and containing 0.8% water.
15 Example 1 - Neutralisation of LAS acid in Fukae mixer
4.0 kg of HMC 1 were charged to a Fukae FS30 high shear granulator/mixer, and mixed using an agitator speed of 200 rpm and a chopper speed of 1300 rpm. Whilst the powder was
' - 5 NOV 2009
t
mixing 1.8 kg of LAS acid was added at a constant rate over a period of 4 minutes using a peristaltic pump. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the
5 solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing powder (flow-rate 130), having a bulk density of 705 kg/m3, and a dissolution time (T90) of 34 seconds.
10
Example 2 - Neutralisation of LAS acid in Ploughshare mixer 12 kg of HMC 1 were charged to a Morton (130 litre) Ploughshare granulator/mixer, and mixed using an agitator speed of 100 rpm and a chopper speed of 1000 rpm. Whilst
15 the powder was mixing 5.09 kg of LAS acid was added at a constant rate over a period of 4.5 minutes using a peristaltic pump. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
20
The granulated product was a readily soluble, free-flowing powder (flow-rate 135), having a bulk density of 532 kg/m3, and a dissolution time (T90) of 30 seconds.
25 Example 3 - Neutralisation of LAS acid in Z blade mixer
0.3'kg of HMC 1 was charged to a Winkworth (Type 2Z) z-blade mixer. Whilst the powder was mixing 0.135 kg of LAS acid was poured in at a constant rate over a period of 4 minutes. On completion of the addition of the LAS acid, mixing was
30 continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing powder (flow-rate 108), having a bulk density of 496 kg/m3, and a dissolution time (T90) of 25 seconds.
5 Example 4 - Neutralisation of LAS acid in high shear mixer 1.0 kg of HMC 1 were charged to a Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed using an agitator speed of 350 rpm and a chopper speed of 1350 rpm. Whilst the powder was mixing 0.45 kg of LAS acid was added 10 at a constant rate over a period of 4 minutes using a
peristaltic pump. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
15 The granulated product was a readily soluble, free-flowing powder (flow-rate 142), having a bulk density of 549 kg/m3, and a dissolution time (T90) of 32 seconds.
Example 5 - Neutralisation of LAS acid by high moisture HMC 20 This is essentially a repeat of Example 1, but using 4.0 kg of higher moisture HMC 2 instead of HMC 1. The HMC was charged to a Fukae FS30 high shear granulator/mixer, and mixed using an agitator speed of 200 rpm and a chopper speed of 1300 rpm. Whilst the powder was mixing 1.54 kg of LAS
25 acid was added at a constant rate over a period of 4 minutes using a peristaltic pump. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
30
The granulated product was a readily soluble, free-flowing powder (flow-rate 144), having a bulk density of 570 kg/m3, and a dissolution time (T90) of 34 seconds.
5 Example 6 - Neutralisation of HMC with a LAS acid/NI blend 400 g of LAS acid was thoroughly mixed with 100 g of ethoxylated alcohol nonionic surfactant {Neodol 2 5-7 ex Shell Chemicals) to form a liquid blend.
10 1.0 kg of HMC 1 was charged to a Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed using an agitator speed of 350 rpm and a chopper speed of 1350 rpm. Whilst the powder was mixing 0.453 kg of the LAS acid/ nonionic surfactant liquid blend was added at a constant
15 rate over a period of 4 minutes using a peristaltic pump. On completion of the addition of the liquid blend, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
20 The granulated product was a readily soluble, free-flowing powder (flow-rate 129), having a bulk density of 655 kg/m3, and a dissolution time (T90) of 40 seconds.
Example 7 - Neutralisation of HMC with a LAS acid/fatty acid 25 blend
400 g of LAS acid was thoroughly mixed with 100 g of fatty acid (Pristerine 4916) to form a liquid blend.
1.0 kg of HMC 1 was charged to a Zanchetta RotoJunior (10 30 litre) high shear granulator/mixer, and mixed using an
agitator speed of 350 rpm and a chopper speed of 1350 rpm.
Whilst the powder was mixing 0.45 kg of the LAS acid/ fatty acid liquid blend was added at a constant rate over a period of 4 minutes using a peristaltic pump. On completion of the addition of the liquid blend, mixing was continued for a
5 further 30 seconds, after which time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing powder (flow-rate 148), having a bulk density of 582 kg/m3,
10 and a dissolution time (T90) of 40 seconds.
Example 8 - Neutralisation of LAS acid in Z blade mixer This is essentially a repeat of Example 3 using the oven dried material HMC 3 in place of the spray dried HMC 1. 0.3 15 kg of oven dried HMC 3 was charged to a Winkworth (model 2Z) z-blade mixer. Whilst the powder was mixing 0.135 kg of LAS acid was poured at a constant rate over a period of 4 minutes. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which
20 time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing powder (flow-rate 111), having a bulk density of 482 kg/m3, and a dissolution time (T90) of 27 seconds.
25
Example 9 - Neutralisation of LAS acid in Z blade mixer This is a repeat of Example 8 using more LAS acid. 0.3 kg of HMC 3 was charged to a Winkworth (model 2Z) z-blade mixer. Whilst the powder was mixing 0.215 kg of LAS acid
30 was poured at a constant rate over a period of 4 minutes. On completion of the addition of the LAS acid, mixing was
continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing
5 powder (flow-rate 120), having a bulk density of 526 kg/m3, and a dissolution time (T90) of 34 seconds.
Example 10 - Neutralisation of LAS acid in high shear mixer This is modification of Example 9 using still more LAS acid
10 and a different mixer. 1.0 kg of HMC 3 was charged to a
Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed using an agitator speed of 350 rpm and a chopper speed of 1350 rpm. Whilst the powder was mixing 0.45 kg of LAS acid was added at a constant rate over a period of 4
15 minutes using a peristaltic pump. On completion of the
addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
20 The granulated product was a readily soluble, free-flowing powder (flow-rate 110), having a bulk density of 557 kg/m3, and a dissolution time (T90) of 33 seconds.
Example 11 - Neutralisation of LAS acid in high shear mixer 25 This is a repeat of Example 10 with even more LAS acid. 1.0 kg of HMC 3 was charged to a Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed using an agitator speed of 350 rpm and a chopper speed of 1350 rpm. Whilst the powder was mixing 0.721 kg of LAS acid was added at a
30 constant rate over a period of 4 minutes using a peristaltic pump. On completion of the addition of the LAS acid, mixing
was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing
5 powder {flow-rate 142), having a bulk density of 655 kg/m3, and a dissolution time (T90) of 42 seconds.
Comparative Example A - Neutralisation of LAS acid with Sodium Carbonate in Fukae
10 This is a comparative example that substitutes the HMC neutralisation process according to Example 1 with an analogous process using unmodified Sodium Carbonate. 4.0 kg of commercial light soda ash (ex Brunner Mond) with mean particle size of 110 micron (Reference Carbonate B) were
15 charged to a Fukae FS30 high shear granulator/mixer, and
mixed using an agitator speed of 200 rpm and a chopper speed of 1300 rprt\. Whilst the powder was being mixed, 1.032 kg of LAS acid was added at a constant rate over a period of 4 minutes using a peristaltic pump. On completion of the
20 addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the product was discharged from the mixer.
This over granulated product had very poor flow properties, 25 having the appearance of wet sand, and was not suitable for use as detergent granules. Even use of lower amounts of surfactant acid did not give satisfactory granules using this process.
30Examples 12 to 16 and B - Dry neutralisation of LAS acid using various carbonate materials
Example 12
30 g of HMC 1 was placed in a laboratory scale granulator (Braun MR 500 CA) and reacted with LAS acid, which was added 5 manually to the granulator, via a syringe, through a small hole drilled in the top of the granulator's lid until the onset of granulation. The weight of LAS acid added at that point was 18 g. Further LAS acid was then added until the granules started to stick together as dough (over-
10 granulation). The maximum amount of LAS acid that could be added to form detergent granules was 29.5 g.
Example 13
20 g of HMC 3 was placed in a laboratory scale granulator
15 (Braun MR 500 CA) and reacted with LAS acid,, which was added manually to the granulator, via a syringe, through a small hole drilled in the top of the granulator's lid until the onset of granulation. The weight of LAS acid added at that point was 15 g. Further LAS acid was then added until the
20 granules started to stick together as dough. The maximum amount of LAS acid that could be added to form detergent granules {before over-granulation) was 31.5 g.
Example 14
25 30g of HMC 4 was placed in a laboratory scale granulator
(Braun MR 500 CA) and reacted with LAS acid, which was added manually to the granulator, via a syringe, through a small hole drilled in the top of the granulator's lid until the onset of granulation. The weight of LAS acid added at that
30 point was 13 g. Further LAS acid was then added until the granules started to stick together as dough. The maximum
amount of LAS acid that could be added to form granules (before over-granulation) was 24.2 g. Example 15
20 g of HMC 5 was placed in a laboratory scale granulator
5 (Braun MR 500 CA) and reacted with LAS acid, which was added manually to the granulator, via a syringe, through a small hole drilled in the top of the granulator's lid until the onset of granulation. The weight of LAS acid added at that point was 13 g. Further LAS acid was then added until the
10 granules started to stick together as dough. The maximum amount of LAS acid that could be added to form granules (.before over-gratwilation) was 24.4 g.
Example 16
15 This example was a repeat of Example 12 with 30 g of HMC 6 replacing the 30 g of HMC 1.
The amount of LAS acid that could be added to the point of "maximum granulation'' (i.e.: maximum amount of LAS acid
20 before over-granulation occurs) was determined to be 37.0 g
Comparative Example B
40 g of commercial anhydrous Sodium Carbonate (Light Ash ex Brunner Mond) (Reference Carbonate B) was placed in a
25 laboratory scale granulator (Braun MR 500 CA) and reacted with LAS acid which was added manually to the granulator, via a syringe, through a small hole drilled in the top of the granulator's lid until the onset of granulation. The weight of LAS acid added at that point was 9 g. Even at
30 this low level of addition of LAS acid, the granules were of poor quality in terms of flow and stickiness. Addition of
' - 5 NOV 2009 *
further LAS acid caused the granules started to form an even stickier mass.
Examples 17-22 showing granulation over a range of LAS/Carbonate ratios.
5 One of the advantages of the inventive process is the
ability to granulate successfully over a wide range of HLAS carbonate ratios. This series of examples were prepared to demonstrate this benefit. The method and materials are the same as for Example 4.
10
The amount of LAS acid added, and key physical properties of
the resulting detergent granules (BD - bulk density, DFR -
Dynamic flow rate, d - Mean particle size, and T90 -
t
dissolution rate) are shown in Table 2. All samples have 15 good granulometry, flow-rate and dissolution properties.
Table 2
Example 17 18 19 20 21 22
LAS acid/HMC w/w 356g/kg 406g/kg 44 9g/kg 502g/kg 544g/kg 624g/kg
BD (kg/m3) 594.45 592.425 619.65 635.625 663.75 743.625
DFR (ml/s) 98 118 120 125 87 85
D
(micron) 365 331 362 392 311 460
T90 (s) 41.7 37 .7 42 44 48.5 57. 5

Comparative Example C: Preparation of Detergent Granules using Burkeite (Reference Carbonate C)
Example 23
200 g of the detergent granules from Example 2 was sprayed in a laboratory scale rotating pan with 6.0 g of perfume oil. The flow rate of the resultant powder was measured as 5 137 g/min.
Example 24
200 g of the detergent powder from Example 2 was sprayed in a laboratory scale rotating pan with 10.0 g of perfume oil. 10 The flow rate of the resultant powder was measured as 140 g/min.
Example 25 - Neutralisation of LAS acid in high shear mixer (no chopping action) 15 1.0 kg of HMC 1 were charged to a Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed using an agitator speed of 350 rpm but with the choppers switched off. Whilst the powder was mixing 0.353 kg of LAS acid was added at a constant rate over a period of 4 minutes using a 20 peristaltic pump. On completion of the addition of the LAS acid, mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer.
The granulated product was a readily soluble, free-flowing 25 powder (flow-rate 146), having a bulk density of 549 kg/m3, and a UCT value of 2.5 kg - this means it would cake easily, for example in silo-storage. Thus, this variant of the process is less preferred due to the lower loading of the anionic surfactant achievable and the caking problem 30 indicated by the high UCT result.
* - 5 NOV 2009
* *
Note that this example is essentially a repeat of Example 4 (which has the choppers/cutters operating) and achieves a higher surfactant content, similar DFR and same bulk density but has been measured to have a UCT of zero and would 5 therefore not have a caking problem.
Example 26 and Comparative Example E - Storage stability 398 g of the detergent granules of Example 2 was stored in an open, plain cardboard carton (dimensions 15.4 cm wide, 10 7.0 cm deep and 13.0 cm high) at a temperature of 28°C and relative humidity of 70%RH for a period of 6 weeks. On removal from storage, these detergent granules had not caked and were still free-flowing (flow rate-133).
15 For comparison, 388 g of the product of Comparative Example A was stored in the same type of cardboard carton under the same conditions for a period of less than 6 weeks. On removal from storage, this powder was heavily caked, in large lumps and did not flow freely from the carton.
20
The granules according to the invention made using habit modified Sodium Carbonate in the dry neutralisation process are non-caking at higher surfactant levels than those made with conventional Sodium Carbonate in the dry neutralisation 25 process.
CLAIMS
1. A process for the manufacture of detergent granules comprising anionic non-soap surfactant the process 5 comprising the dry neutralisation of surfactant acid
with habit modified Sodium Carbonate, which is a crystal growth modified Sodium Carbonate that comprises a mixture of Sodium Carbonate and polymer.
10 2. A process according to claim 1 in which the surfactant acid is used in liquid form.
3. A process according to any preceding claim in which the surfactant acid is reacted while mixing with a molar 15 excess of habit modified Sodium Carbonate to form a
sodium salt of the anionic surfactant, while mixing.
4. A process according to claim 3 in which the mixing is carried out in a mixer with a chopping action and the 20 chopping action is used during the dry neutralisation
reaction.
5. A process according to claim 4 in which the mixing is carried out in a mixer, which has both a stirring
25 action and a cutting action, and both actions are used
during the dry neutralisation reaction.
6. A process according to any preceding claim in which the neutralising agent compasses a mixture of habit
30 modified carbonate with a smaller amount of Sodium
Carbonate and/or Burkeite.
7. A process according to any preceding claim in which the habit modified Sodium Carbonate is characterised by having a specific surface area of 5 m2/g or greater, 5 preferably 8 m2/g or greater, even more preferably 10
m2/g or greater..
8. A process according to claim 7 in which the habit
modified Sodium Carbonate is characterised by having
10 a pore volume, in pores less than 2 micron diameter,
of 0.3 ml/g or greater.
9. A high active detergent granule comprising:
a) greater than 30 wt% anionic surfactant, said
15 surfactant comprising a major part of non-soap anionic
surfactant,
b) habit modified Sodium Carbonate, which is a crystal growth modified Sodium Carbonate that comprises a mixture of Sodium Carbonate and polymer, and
20 c) less than 10 wt%, preferably zero, zeolite,
obtainable by the process according to any preceding claim.
25 10. A detergent granule according to claim 9 characterised in that the non-soap anionic surfactant level in the granule is greater than 30 wt%, preferably greater than 35 wt%, even greater than 40 wt% and preferably even greater than 45 wt%.
11. A detergent granule according to claim 9 or claim 10, further comprising perfume.
12. A detergent granule according to any one of claims 9 to 5 11, further comprising nonionic surfactant.
13. A detergent granule according to any one of claims 9 to 12, further comprising soap.
1.5 kg of the spray-dried Reference Carbonate C were charged
to a Zanchetta RotoJunior (10 litre) high shear granulator/
5 mixer, and mixed using an agitator speed of 350 rpm and a
chopper speed of 1350 rpm. Whilst the powder was mixing
0.15 kg of LAS acid was added at a constant rate over a
period of 2.5 minutes. On completion of the addition of the
LAS acid, mixing was continued for a further 30 seconds,
10 after which time, the solid product was discharged from the mixer. The granulated product was a free-flowing powder (flow-rate 115) , having a bulk density of 715 kg/rn3.
Comparative Example D: Preparation of Detergent Granules 15 using milled ash.
1.5kg of Sodium Carbonate (light ash ex Brunner Mond) that had previously been milled to a mean particle size of 50 micron {Reference Carbonate D) were charged to a Zanchetta RotoJunior (10 litre) high shear granulator/mixer, and mixed 20 using an agitator speed of 350 rpm and a chopper speed of
1350 rpm. Whilst the powder was mixing 0.364 kg of LAS acid was added at a constant rate over a period of 5.75 minutes. The amount added was just sufficient to prevent over- granulation . On completion of the addition of the LAS acid, 25 mixing was continued for a further 30 seconds, after which time, the solid product was discharged from the mixer. The granulated product was a free-flowing powder (flow-rate 90), having a bulk density of 705 kg/m3.
30 Examples 23 and 24 - Perfume loading of detergent granules