WO2011058032A1

WO2011058032A1 - Free flowing detergent granule

Info

Publication number: WO2011058032A1
Application number: PCT/EP2010/067170
Authority: WO
Inventors: Priyadarshi Bhattacharya; Sujitkumar Suresh Hibare; Jiji Paul Kottukapally; Suresh Murigeppa Nadakatti
Original assignee: Unilever Nv; Unilever Plc; Hindustan Unilever Limited
Priority date: 2009-11-13
Filing date: 2010-11-10
Publication date: 2011-05-19

Abstract

The present invention is in the field of detergent granules. The invention particularly relates to free flowing detergent granules comprising a high concentration of liquid active material produced by non tower route (NTR). It is an object of the present invention to provide a solid detergent granule comprising a high amount of liquid active (surfactant). It has been found that a granule comprising up to 30% by weight of the granule of a surfactant that is a liquid at room temperature, or added in the form of a liquid solution in the core of the granule and which is coated with an inorganic layering agent, shows both good flow properties and detergency benefits.

Description

FREE FLOWING DETERGENT GRANULE

Field of the Invention

The present invention is in the field of detergent granules. The invention particularly 5 relates to free flowing detergent granules comprising a high concentration of liquid active material produced by non tower route (NTR).

Background of the invention

Detergent products are widely used by consumers, such as for cleaning laundry and 10 hard surfaces.

Detergent product generally contain surfactant, builder, electrolyte, pH adjustment agents and usually also a perfume. Surfactants are widely used in detergent compositions for releasing and immobilising soils. Detergent compositions containing 15 high concentrations of surfactant, also known as high active detergents, have been proposed in the art.

Such high active compositions are predominantly liquid compositions, such as disclosed in US 5,607,910, wherein a liquid composition is proposed comprising up to 20 70% surfactant (also referred to as active).

Similarly in US 2003/0092594, super concentrated liquid detergent compositions are disclosed.

25 High active solid detergent compositions remain to be desired. The reason for this is that although some surfactants are solid at room temperature, most surfactants are liquids. On top of that many solid surfactants are only commercially available in the form of liquid solutions or pastes.

30 It is an object of the present invention to provide a solid detergent granule comprising a high amount of liquid active (surfactant). It is another object of the invention to provide a free flowing solid detergent granule and detergent composition.

It is yet another object of the invention to provide such a free flowing detergent granule which is substantially free or even entirely free of phosphate.

Surprisingly it has been found that a granule comprising up to 30% by weight of the granule of a surfactant that is a liquid at room temperature, or added in the form of a liquid solution in the core of the granule and which is coated with an inorganic layering agent, shows both good flow properties and detergency benefits.

Summary of the invention

Accordingly, the present invention provides a free flowing solid detergent granule comprising a core comprising 10-30% by weight of the granule surfactant, 20-60% by weight of the granule of non-phosphate builder and 10-30% by weight of the granule electrolyte and a shell comprising 10-35% by weight of the granule of an inorganic layering agent selected from calcite and magnesium carbonate and combinations thereof, which is characterised in that; the weight ratio of layering agent to surfactant is between 1 :4 and 1 .5:1 ; and the detergent granule has a dynamic flow rate of at least 65 ml/s, measured in a standard vertical tube and cone dynamic flow rate device, having a tube of 3.5 cm inner diameter, and a cone angle of 15° and a cone orifice of 2.25 cm.

In another aspect the present invention provides a detergent composition comprising the granule according to the invention.

In another aspect the present invention provides a process for preparing the granule according to the invention. These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of." In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. Brief description of the drawing

Figure 1 shows a standard dynamic flow rate measurement set up

Detailed description of the invention

The free flowing solid detergent granule comprises a core and a shell.

Core

The core of the granule comprises surfactant, builder and electrolyte.

In general, the surfactants of the surfactant system may be chosen from the surfactants described well known textbooks like "Surface Active Agents" Vol. 1 , by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, and/or the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981 . Preferred surfactants in the context of the present invention are surfactants that are in liquid form, including surfactants that are liquid or paste at room temperature, or liquid solutions surfactant. Especially preferred surfactants are anionic surfactants, e.g. Linear Alkyl benzene Sulphonic acid (LAS), Alkyl Ether sulphates, containing an alkyl chain of between 10 and 18 carbon atoms and between 0 and 10 ethylene oxide (EO) groups, more preferably between 1 and 7 EO groups, still more preferable 1 -5 EO. An example of such a surfactant is SLES-3EO (Sodium Lauryl Ether Sulphate, 3EO). Also preferred in the context of the present invention are nonionic surfactants from the group of condensation products of fatty alcohols having a carbon chain of between 8 and 18 carbon atoms and containing between 1 and 10 EO groups, more preferably between 5 and 9 EO. A neutralisation agent may be required in case the surfactant is dosed in acid form (e.g. LAS). In the context of the invention, the neutralisation agent is preferably selected from alkali metal or alkaline earth carbonates, e.g. Sodium carbonate. These carbonates, may at the same time act as builder. When present, the neutralisation agent is typically present in a 0 to 100% stoichiometric excess of the acid surfactant (also known as acid surfactant precursor). In the granules of the present invention it is preferred that the neutralisation agent is present in a concentration of between 0.5 and 6%.

The surfactant is present in the granule in a concentration of between 10 to 30% based on the total weight of the granule.

Builders are typically selected from sodium carbonate, sodium silicate, zeolite, sodium tri poly phosphate and mixtures thereof. The builder is preferably in powder form. However, at present the use of phosphate based builder is restricted more and more by legislation and consumer preference. Phosphate builder has excellent formulation properties and therefore used to be the builder of choice form making free flowing granules. Zeolite and silicate based builders are relatively expensive and do not provide good building, especially in hard water conditions. Therefore sodium carbonate is the most preferred builder, even though it is more difficult to make free flowing granules with it, especially when using non-tower-route (also referred to as NTR) processes.

Builders are present in the granule in a concentration of between 20 to 60% by weight based on the total weight of the granule, preferably 30 to 50%. by weight. Electrolytes are typically selected from chloride or sulphate salts of alkali metals or alkaline earth metals, the most preferred electrolytes are sodium chloride or sodium sulphate. The electrolyte is preferably in powder form

Electrolytes are present in the granule in a concentration of between 10 to 30% based on the total weight of the granule.

The core of the granule may further comprise additional ingredients, including fluorescers, anti-microbial agents, anti-redeposition agents, dye transfer inhibitors, bleaching agents, perfume material, coloured speckels and/or enzymes.

Shell

The shell of the granule comprises an inorganic layering agent.

The layering agent comprises a water insoluble inorganic layering agent selected from calcite, magnesium carbonate and combinations thereof. Calcite gives the best results, while Magnesium Carbonate because it already gives very good results at low dosage.

The layering agent may further comprise a water soluble inorganic layering agent chosen from sodium carbonate, sodium bicarbonate, sodium tripoly phosphate, sodium chloride, sodium sulphate and combinations thereof. The water soluble layering agent is most preferably selected from sodium carbonate and sodium bicarbonate.

The water soluble inorganic layering agent is preferably selected from Na₂C0₃, and NaHC0₃,. The water soluble inorganic layering agent preferably does not comprise salts selected from sulphates and NaCI.

In another embodiment the shell comprises both the water soluble and the water insoluble inorganic layering agent, and comprises an inner shell layer and an outer shell layer, wherein the inner shell layer predominantly comprises of the water soluble layering agent and the outer shell layer predominantly comprises of the water insoluble layering agent; wherein with predominantly is meant more than 55%, preferably more than 65%, still more preferably more than 75%, even more preferably more than 85%, or even more than 95% by weight.

The weight ratio of the combined water soluble and water insoluble layering agent : surfactant is between 1 :4 and 1.5: 1 , preferably between 1 :2 and 1 :1 .

When the optional water soluble inorganic layering agent is present, the ratio of water soluble to water insoluble inorganic layering agent is preferably between 5:1 to 1 :5, more preferably between 2:1 and 1 :2.

Detergent composition

In another aspect, the present invention provides a detergent composition comprising the granule of the invention. The detergent composition may contain up to 100% of the granule. Typically the detergent composition comprises between 50 and 99% of the granule.

The detergent composition may further comprise additional solid free flowing material, including solid surfactant powder or granules, electrolyte salts, fluorescers, antimicrobial agents, anti-redeposition agents, dye transfer inhibitors, bleaching agents, perfume and/or enzyme granules. Optionally the detergent composition may comprise additional builder material; adding separate builder material may provide faster building of the wash liquor, therefore softening the water before the surfactant from the granule of the invention dissolves into the wash liquor.

5 Process for making the granule

The process for manufacturing a free flowing solid detergent composition granule comprising the sequential steps of

Mixing the builder and the electrolyte;

Adding the liquid surfactant active;

10 - Adding a water insoluble inorganic layering agent selected from calcite, zeolite, magnesium carbonate or precipitated silica.

The the weight ratio of layering agent : surfactant is between 1 :4 and 1 .5:1 and having a dynamic flow rate of at least 55 ml/s, measured in a standard tube and cone dynamic flow rate device, having a tube of 3.5 cm inner diameter, and a cone angle of 15 15° and a cone orifice of 2.25 cm.

In another embodiment the layering agent in step c, further comprises a water soluble inorganic layering agent having a low hygroscopicity.

20 In another embodiment a water soluble inorganic layering agent having low

hygroscopicity is added, between the liquid active and the water insoluble layering agent.

Flow properties

25 The detergent granule preferably has a dynamic flow rate of at least 55 ml/s,

preferably at least 60 ml/s, more preferably at least 65ml/s, even more preferably at least 70ml/s, yet more preferably at least 75ml/s, still more preferably at least 80 ml/s, or even at least 100 ml/s, measured with a vertical tube and cone DFR method, having a tube (T) with an inner diameter (DT) of 3.5 cm inserted in to a cone (C)

30 having an angle (A) of 15° and an orifice diameter (DO) of 2.25cm (See figure 1 ).

Such devices are commercially available (e.g. Model DFR-403F, ex Silikon

Technologies, India) and well known in the art. The tube is preferably about 50 cm high and preferably has a level marking scale. The flowrate is measured by closing the cone orifice, filling the tube and cone with the material, opening the orifice and measuring the time for a predetermined volume (based on the marking scale of the tube or of the volume collected at the outlet) of the material to flow out from the cone orifice.

The same flow properties are preferred for the detergent composition comprising the granule.

Examples

The invention will now be illustrated by means of the following non-limiting examples.

Example 1 : Preparation of granules according to the invention.

The following ingredients were mixed

2) These are liquid/paste surfactants 3) combined neutralization agent and builder

4) Including moisture

Granule 1

The heating jacket of a 15 litre capacity standard z-blade mixer (ex Sigma) heated by circulating water at 80°C to make sure the mixer walls are hot. This is to mimic the factory condition where batches are made one after the other and mixer is always hot (i.e. about 80°C). Sodium carbonate and sodium chloride powder were then charged into the mixer and mixed for 1 minute. SLES paste (67%; sodium lauryl ether (E03) sulphate, ex Galaxy, India) and non-ionic surfactant (condensation product of C12 alcohol and 7 ethylene oxide groups (E07), ex Galaxy, India) were added to the mixer and mixed with the powders for 2 minutes. LAS acid (linear alkylbenzene sulphonic acid, ex Reliance, India) was slowly added over 2 minutes and mixed for 30 seconds post addition. After that the hot water circulation of the heating jacket was switched off. Calcite (forcalU, precipitated calcium carbonate, Saurashtra Solid Industry Pvt Ltd, India) layering agent was added to the mixer and mixed in for 30 seconds. Minors (mostly perfume and fluorescer) were added and mixed for 1 minute for homogeneous mixing. The product was sieved through 2mm sieve to take out oversize and the remaining granules were measured for the yield of the desired cut.

Granule 2

A Plough-Share mixer (40 litre capacity with 2 ploughs and one chopper) heating jacket was heated by circulating water at 80°C to make sure the mixer walls are hot. This is to mimic the factory condition where batches are made one after the other and mixer is always hot. sodium carbonate and sodium chloride were added into the mixer and mixed for 1 minute at 200 rpm with chopper kept on. SLES paste (67%) and non- ionic surfactant and again mix them with the powders for 2 minutes. The mixing speed was reduced to 150 rpm and LAS acid was slowly added over 2 minutes and mix it for 30 seconds post addition. Hot water heating to the jacket was switched off. The material from was taken out of the mixer and transferred to the Sigma mixer. Layering with calcite (forcalU) is done in the Sigma mixer. Minors (mostly perfume and fluorescer) were added and mixed for 1 minute for homogeneous mixing. The product was sieved through 2mm sieve to take out oversize and the remaining granules were measured for the yield of the desired cut.

Granule 10 (combined water soluble and insoluble layering agent)

A Plough-Share mixer (40 litre capacity with 2 ploughs and one chopper) heating jacket was heated by circulating water at 80°C to make sure the mixer walls are hot. This is to mimic the factory condition where batches are made one after the other and mixer is always hot. sodium carbonate and sodium chloride were added into the mixer and mixed for 1 minute at 200 rpm with chopper kept on. SLES paste (67%) and non- ionic surfactant and again mix them with the powders for 2 minutes. The mixing speed was reduced to 150 rpm and LAS acid was slowly added over 2 minutes and mix it for 30 seconds post addition. Hot water heating to the jacket was switched off. The material from was taken out of the mixer and transferred to the Sigma mixer. Layering with combined calcite (forcalU) and Soda (Na₂C0₃) is done in the Sigma mixer. Minors (mostly perfume and fluorescer) were added and mixed for 1 minute for homogeneous mixing. The product was sieved through 2mm sieve to take out oversize and the remaining granules were measured for the yield of the desired cut.

Granule 1 1 (dual shell layer)

A Plough-Share mixer (40 litre capacity with 2 ploughs and one chopper) heating jacket was heated by circulating water at 80°C to make sure the mixer walls are hot. This is to mimic the factory condition where batches are made one after the other and mixer is always hot. sodium carbonate and sodium chloride were added into the mixer and mixed for 1 minute at 200 rpm with chopper kept on. SLES paste (67%) and non- ionic surfactant and again mix them with the powders for 2 minutes. The mixing speed was reduced to 150 rpm and LAS acid was slowly added over 2 minutes and mix it for 30 seconds post addition. Hot water heating to the jacket was switched off. The material from was taken out of the mixer and transferred to the Sigma mixer. Layering is first done with the Na2C03 layering material and then with calcite (forcalU); both sequentially done in the Sigma mixer. Minors (mostly perfume and fluorescer) were added and mixed for 1 minute for homogeneous mixing. The product was sieved through 2mm sieve to take out oversize and the remaining granules were measured for the yield of the desired cut.

The dynamic flow rate (DFR) was measured using a commercially available tube and cone DFR device from Silicon Technologies (India), comprising a tube with a 3.5 cm inner diameter and a cone having an angle of 15° and a cone orifice of 2.25cm; the tube being inserted into the cone.

The table above shows that both processes provide granules with suitable dynamic flow rates.

Example 2: Layering agents.

The process of Granule 1 was used, but the type and amount of inorganic layering agent was varied; Calcite, Zeolite, Magnesium carbonate (MgC0₃) and precipitated silica were used. When there is too little layering agent, the granules are not free flowing; when too much layering agent is added, the layering agent excess adds unnecessarily to the cost of the product and also has a negative influence on the flow behaviour.

In these examples the minimum and maximum amount of layering agent for preferred particles according to the invention are given

The base material (excluding layering agent is given in the table below. Parts (by weight)

Sodium carbonate (Na2C03) 40

Sodium Chloride (NaCI) 19

SLES - E03 7

Nl (C12 alcohol - E07) 3

LAS 10

Minors 7(including moisture)

The layering agent was gradually added to this base material, and several samples were taken from the mixer during the addition.

The dynamic flow rate (DFR) of all samples Samples was measured and the upper land lower limit for each layering agent was given.

The table above shows the upper and lower limits (UL and LL) for the amount of the different layering agents added to the bas material to for the "best mode" particles. Below the lower limit, the particles do not flow. At the Lower Limit, the particles start giving good flow behaviour (above about 55 ml/min) and at up to the upper limit the particles still show good flow behaviour. Above the upper limit the flow becomes poor due to segregation happening at high inorganic content

Example 3: Sequence of addition

In this example the sequence of addition of the layering agent was varied to show the effect on the dynamic flow rate. The calcite layering agent is now added before, during and after the addition of the last liquid surfactant.

The base powder is given in the below table.

To the base powder 14% of Calcite layering agent was added.

First the builder and electrolyte were mixed; then SLES (sodium lauryl ether sulphate) and Nl (non-ionic surfactant) were added and mixed into the mixture. Then 3 different sequences for added the last liquid surfactant and the layering agent were tested (see table below). Material Sequence

Granule 7 Calcite before LAS

Granule 8 Calcite and LAS together

Granule 9 Calcite after LAS

The dynamic flow rates were measured as above.

Material DFR (ml/s)

Granule 7 No Flow

Granule 8 No Flow

Granule 9 108 This set of examples clearly shows that the particle according to the invention

(granule 9), which forms a base material core and a shell of layering agent gives good flow characteristics, while Granules 7 and 8, which form granules without a shell of layering agent, do not flow at all.

Claims

1 Free flowing solid detergent granule comprising

a. a core, prepared by an NTR process, comprising:

i. 10-30% by weight of the granule of surfactant, ii. 20-60% by weight of the granule of non-phosphate builder, and iii. 10-30% by weight of the granule of electrolyte; and

b. A shell comprising:

i. a water insoluble inorganic layering agent selected from calcite, magnesium carbonate, and combinations thereof; characterised in that;

the weight ratio of layering agent : surfactant is between 1 :4 and 1 .5:1 ; and the detergent granule has a dynamic flow rate of at least 65 ml/s, measured in a standard vertical tube and cone dynamic flow rate device, having a tube of 3.5 cm inner diameter, and a cone angle of 15° and a cone orifice of 2.25 cm.

2 A granule according to claim 1 , wherein the shell further comprises a water soluble inorganic layering agent selected from sodium carbonate, sodium bicarbonate, sodium tripoly phosphate, sodium chloride, sodium sulphate and combinations thereof.

3 A granule according to claim 2, wherein the shell comprises an inner shell layer and an outer shell layer, wherein the inner shell layer predominantly comprises of the water soluble layering agent and the outer shell layer predominantly comprises of the water insoluble layering agent.

4 A granule according to any one of the preceding claims, wherein the surfactant is selected from anionic surfactants, non-ionic surfactants or mixtures thereof.

5 A granule according to any one of the preceding claims, wherein at least part of the surfactant is dosed in the form of a liquid. A granule according to any one of the preceding claims, wherein 50-100% of the surfactant is dosed in the form of a liquid. A granule according to any one of the preceding claims wherein the average particle size is between 600-1200 micrometer and wherein the 80% of the particles in between 200 and 2000 micrometer A detergent composition comprising the granule according to any one of the preceding claims. Process for manufacturing a free flowing solid detergent composition granule comprising the steps of:

a. Mixing

i. 20-60% by weight of the granule of builder; and

ii. 10-30% by weight of the granule of electrolyte;

b. Adding 10-30% by weight of the granule of a liquid surfactant active; c. Adding a water insoluble inorganic layering agent selected from calcite, zeolite, magnesium carbonate or precipitated silica; and

characterised in that the weight ratio of layering agent : surfactant is between 1 :4 and 1 .5:1 and having a dynamic flow rate of at least 55 ml/s, measured in a standard tube and cone dynamic flow rate device, having a tube of 3.5 cm inner diameter, and a cone angle of 15° and a cone orifice of 2.25 cm. A process according to claim 9, wherein the layering agent in step c, further comprises a water soluble inorganic layering agent . A process according to claim 9, wherein between steps b and c, a further step is included, wherein a water soluble inorganic layering agent is added..