WO2011147646A1

WO2011147646A1 - Builder composition and process for building

Info

Publication number: WO2011147646A1
Application number: PCT/EP2011/056226
Authority: WO
Inventors: Sujitkumar Suresh Hibare
Original assignee: Unilever Nv; Unilever Plc; Hindustan Unilever Limited
Priority date: 2010-05-24
Filing date: 2011-04-19
Publication date: 2011-12-01

Abstract

The present invention is in the field of detergent powders. The invention particularly relates to a builder composition providing sequential building of Magnesium and Calcium hardness ions. Although a lot of progress is made, the problem of getting fast building and building to a very low level of hardness ions remains to be desired, especially achieving this without the use of phosphate builder material. It is an object of the invention to reduce magnesium ion poisoning of a laundry builder system. The present inventors have found that when magnesium ions are removed from the water before the calcium building is started the overall building is faster and the overall removal of hardness ions is improved.

Description

BUILDER COMPOSITION AND PROCESS FOR BUILDING Field of the Invention

The present invention is in the field of detergent powders. The invention particularly relates to a builder composition providing sequential building of magnesium and calcium hardness ions.

Background of the invention

Reducing the hardness of washing water has been one of the major challenges in the development of laundry detergent materials for decades and has become a more pressing issue due to the demand from consumers and governments to reduce or abolish the use of phosphate builders in detergent products.

Hardness in water is predominantly caused by calcium (Ca²⁺) and magnesium (Mg²⁺) ions, and causes reduced efficiency of surfactants in water, surfactant precipitation, as well as deposition of lime scale in washing machines.

The better the building (i.e. removal of calcium and magnesium hardness ions from laundry water) is, the lower is the loss of surfactant. By better building is understood, both fast removal of the hardness ions and efficient removal, i.e. removal to a low level. Surfactant precipitation also leads to re-deposition onto fabrics, which is not desired.

One alternative builder to phosphate is sodium carbonate, typically used together with small amounts of calcite acting as precipitation seed material.

However, although sodium carbonate is a very good builder for calcium ions, its efficiency is dramatically reduced by the presence of magnesium ions.

Other builders next to sodium carbonate have also been disclosed in the art, for instance in GB 1395305, US 5419850, US2003-224961 and EP-B-178893.

However, the problem of poisoning of the sodium carbonate / calcite builder by magnesium ions remains to be solved. GB 1395305 discloses a detergent composition which may contain a builder. Various compounds are given as possible builders including sodium carbonate and calcium hydroxide. A preferred example gives a composition containing 8- 14% Na₂CO₃ and 0-2% Ca(OH)₂, amongst other constituents.

US 5419850 discloses a phosphate-free detergent block comprising 5-40% of an alkali metal hydroxide and 5-25% of an alkali metal carbonate. The carbonate may by sodium carbonate but there is no apparent mention of the hydroxide being an alkali earth metal or of calcium hydroxide.

US2003-224961 discloses a cleaning composition comprising 20-95% of a builder which may be sodium carbonate. The composition may also include 0.1 - 20% of an alkali compound which may be calcium hydroxide, although this does not appear to be part of the builder.

EP-B-178893 discloses a solid detergent composition which may comprise 5- 25% of an alkali metal hydroxide, a phosphate hardness sequestering agent and 5-35% hydrated sodium carbonate, although there is no specific mention of calcium being the alkali metal and the composition includes a phosphate.

However, although a lot of progress is made, the problem of getting fast building and building to a very low level of hardness ions remains to be desired, especially achieving this without the use of phosphate builder material. Without wishing to be bound by a theory, it is though that the presence of magnesium hardness ions poison sodium carbonate as a builder and reduces its efficiency.

It is therefore an object of the invention to reduce magnesium ion poisoning of a laundry builder system. It is another object of the invention to provide for sequential building of magnesium ions and calcium ions.

The present inventors have found that when magnesium ions are removed from the water before the calcium building is started the overall building is faster and the overall removal of hardness ions is improved.

Summary of the invention

Accordingly the present invention provides a builder composition comprising 5- 40 parts by weight of calcium hydroxide particles having a particle size of between 1 and 20 micrometer 60-95 parts by weight of sodium carbonate particles having a particle size of between 200 and 2500 micrometer.

In another aspect the invention provides a detergent composition comprising between 20 and 70% by weight of the builder composition according to anyone of claims 1 to 3; between 10 and 30% by weight of a surfactant and between 5 and 15% by weight of an electrolyte.

In a third aspect there is provided a method of use of a builder composition comprising calcium hydroxide particles having a particle size of between 1 and 20 micrometer and sodium carbonate particles having a particle size of between 200 and 2500 micrometer for sequential building of magnesium and calcium hardness ions. By building is meant the removal of hardness ions, especially calcium and magnesium for water.

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.

Detail description of the invention

The present invention provides a builder composition comprising calcium hydroxide particles and sodium carbonate particles, and a detergent

composition comprising the builder composition according to the invention.

Builder composition

The builder composition according to the invention comprises relatively small particles of calcium hydroxide (Ca(OH)₂) particles and relatively large particles of sodium carbonate particles (Na2CO3).

The builder composition comprises between 5 and 40 parts by weight of calcium hydroxide particles; preferably at least 10 parts by weight, more preferably at least 15 parts by weight, but preferably not more than 35 parts by weight and more preferably not more than 30 parts by weight, or even not more than 25 parts by weight. The average diameter (hereinafter referred to as the particle size) of the calcium hydroxide particles is between 1 and 20

micrometer, preferably at least 2 micrometer, or even at least 5 micrometer, while the particle size is preferably not more than 18 micrometer, or even not more than 15 micrometer. It is preferred that at least 50%, more preferably at least 75%, or even more preferably at least 90%, of the calcium hydroxide particles has a particle size within 50% of the average, more preferably within 30% of the average, or even within 20% of the average particle size. The builder composition comprises between 60 and 95 parts by weight of sodium carbonate particles; preferably at least 65 parts by weight, more preferably at least 70 parts by weight, still more preferably more than 75 parts by weight, but preferably not more than 90 parts by weight and more preferably not more than 85 parts by weight. The average diameter (hereinafter referred to as the particle size) of the sodium carbonate particles is between 200 and 2500 micrometer, preferably at least 300 micrometer, or even at least 500

micrometer, while the particle size is preferably not more than 2000 micrometer, more preferably not more than 1500 micrometer, or even not more than 1000 micrometer. It is preferred that at least 50%, more preferably at least 75%, or even more preferably at least 90%, of the sodium carbonate particles has a particle size within 50% of the average, more preferably within 30% of the average, or even within 20% of the average particle size.

To obtain the maximum of reducing magnesium poisoning of the sodium carbonate builder, it is especially preferred that not more than 10% of the sodium carbonate is dissolved within 30 seconds after dosing the builder composition or detergent product comprising the builder composition to the laundry water at 25°C under agitation, preferably it is preferred that not more than 10% is dissolved within 1 minute, while at least 90% of the sodium carbonate should be dissolved within 10 minutes, preferably within 5 minutes.

The builder composition according to the invention may further comprise between 1 and 35 parts by weight of a seed material, more preferably between 5 and 30 parts by weight or even more preferably between 10 and 25 parts by weight. The seed material may be selected from calcite or dolomite. The most preferred seed material is calcite.

The builder composition may further comprise additional builder materials, but in view of the consumer preference the composition according to the invention is preferably free of phosphate builder material. Also, in view of fabric ashing, zeolite builders are typically not preferred.

Detergent composition

The detergent composition according to the invention comprises between 20 and 70% by weight of the builder composition according to the invention.

For top load washing machine application, the detergent composition preferably comprises at least 40%, or even at least 50% by weight of the detergent composition, preferably not more than 65% or even more preferably not more than 60% by weight of the detergent composition.

For front load washing machine application and hand wash, the detergent composition preferably comprises at least 30%, or even at least 40% by weight of the detergent composition, preferably not more than 60% or even more preferably not more than 55% by weight of the detergent composition.

The detergent composition further comprises between 10 and 30% by weight of a surfactant. The surfactant may be selected from the surfactants described in 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 .

Anionic surfactants are the most preferred, especially linear alkyl benzene sulphonate, alkyl sulphates, alkyl ether sulphates, alpha olefin sulphonate and primary and secondary alkyl sulphonates. Anionic surfactants preferably make up at least 50% by weight of the total surfactant in the composition, more preferably at least 70% by weight. The composition my further comprise non-ionic surfactants. Especially preferred are ethoxylated fatty alcohols, comprising between 1 and 10, ethylene oxide groups and a fatty alcohol chain length of between 8 and 22 carbon atoms, preferably between 12 and 18 carbon atoms. The detergent composition according to the invention optionally comprises of between 0 and 15% by weight, preferably between 5 and 13% by weight of an electrolyte. The electrolyte may be preferably selected from sodium chloride, sodium sulphate; sodium chloride being the most preferred. The electrolyte may also act as filler material. This electrolyte excludes the builder material.

Optional ingredients

The detergent composition may further comprise fluorescers, shading dyes, anti-microbial agents, anti-redeposition agents, dye transfer inhibitors, bleaching agents, perfume and/or enzyme granules.

Process

The invention further provides a method of use of a builder composition comprising calcium hydroxide particles having a particle size of between 1 and 20 micrometer and sodium carbonate particles having a particle size of between 200 and 2500 micrometer for sequential building of magnesium and calcium hardness ions in hard water. In a preferred embodiment, the a builder composition according to claim 1 is used for sequential building of magnesium and calcium hardness ions in hard water Additionally a method for building (i.e. removing hardness ions from water) comprising the steps of adding a builder composition comprising calcium hydroxide particles having a particle size of between 1 and 20 micrometer and sodium carbonate particles having a particle size of between 200 and 2500 micrometer to water comprising hardness ions.

For water having a hardness of between 6 and 72 °fH, typically 24 to 48 °fH, it is preferred that between 0.1 g/L and 2.5 g/L of the builder composition according to the invention is used, preferably at least 0.25 g/L, more preferably at least 0.4 g/L, still more preferably at least 0.5 g/L, but typically not more than 2 g/L, more preferably not more than 1 .5 g/L or even not more than 1 .0 g/L for top load machines, while and it is preferred that between 0.2 g/L and 4 g/L of the builder composition according to the invention is used, preferably at least 0.5 g/L, more preferably at least 1 g/L, still more preferably at least 1 .5 g/L, but typically not more than 3 g/L, more preferably not more than 2.5 g/L for front load machines and hand wash application. It is preferred that the total dose of detergent composition, including the builder composition to a washing machine is between about 25 and 150 g of detergent per wash in a standard 60 L water intake top load washing machine, preferably between 70 and 125 g per wash, more preferably between 80 and 100 g per wash.

For front load washing machines and for hand wash processes, both using approximately 15 L of water intake is between about 25 and 150 g of detergent per wash, preferably the detergent product comprising the builder is dosed in an amount of between 30 and 100 g, more preferably between 50 and 90 g per wash, still more preferably between 60 and 80 g per wash.

Examples

The invention will now be illustrated by means of the following non-limiting examples. Example 1 : Effect of delayed release of calcium builder

In this experiment a tergo-to-meter was used, a commonly used small scale washing test device, consisting of a 1000 mL effective volume container and an agitator.

The tergo-to-meter is filled with 1000 mL of hard water, of 48 °fH (2:1

calcium:magnesium). The test is done at 25°C and the agitator is set to 90 rpm.

The builder composition for this example consisted of 0.6 g of sodium carbonate and 0.15 g of calcium hydroxide.

In comparative experiment A, sodium carbonate and calcium hydroxide were added together as fine powders (less than 20 micrometer cut). In experiment 1 , calcium hydroxide powder was added first followed by sodium carbonate powder after 1 minute. The same less than 20 micrometer cut powders were used.

The water hardness was measured by titration using 0.4266 mM EDTA solution, a well known method in the art.

Results

Time Hardness (°fH)

(min) Comparative Experiment A Experiment 1

0 52.0 52.0

1 43.5 55.0

2 39.7 23.0

3 36.3 12.8

5 31 .1 9.8

7 23.9 8.1

10 21 .3 8.5

15 14.5 6.4 It is clear from the results above that building Mg2+ first (with calcium

hydroxide) and Ca2+ later (with sodium carbonate) reduces the water hardness better (faster and further) than building co-currently. Example 2: Effect of delayed release of calcium builder

This example was carried out in the same manner as Example 1 , but now a small amount of seed material was added together with the sodium carbonate.

The builder composition for this example consisted of 0.6 g of sodium carbonate, 0.2 g of calcite and 0.15 g of calcium hydroxide.

In comparative experiment B, sodium carbonate, calcite and calcium hydroxide were added together as fine powders. The same less than 20 micrometer cut Ca(OH)₂ and Na2CO3 were used as in example 1 .

In experiment 2 calcium hydroxide powder was added first followed by sodium carbonate powder and calcite (less than 20 micrometer cut) after 1 minute. The same less than 20 micrometer cut Ca(OH)₂ and Na2CO3 were used as in example 1 .

The water hardness was measured by EDTA titration.

Results

Time Hardness (°fH)

(min) Comparative experiment B Experiment 2

0 46.1 46.1

1 26.9 48.0

2 23.0 13.4

3 19.2 9.6

5 17.3 9.6

7 15.3 9.6

10 13.4 7.6

15 9.6 7.6 As seen in the table above, calcite seed addition, the normal way to improve building, improves the overall building, but sequential building of Mg2+ and Ca2+, still gives faster overall building and a lower final water hardness, which is important to avoid loss of surfactant due to surfactant poisoning

(precipitation).

Example 3: Effect of delayed release of calcium builder, in a washing machine In this experiment a commercially available Samsung model WA80TAL Silver Nano top load washing machine.

The machine was operated on the normal main wash program with 60 L of hard water of 48 °fH (2:1 calcium:magnesium), at room temperature (25°C).

The builder composition for this example consisted of 36 g (=0.6 g/L) of sodium carbonate, 18 g (=0.3 g/L) of calcite and 12 g (0.2 g/L) of calcium hydroxide.

In comparative experiment C, sodium carbonate, calcite and calcium hydroxide were added together as fine powders. The same less than 20 micrometer cut Ca(OH)₂, calcite and Na2CO3 were used as in example 1 .

In experiment 3, sodium carbonate granules (of a 0.5-2 mm cut), calcite and calcium hydroxide (less than 20 micrometer cut) were added together.

The water hardness was measured by EDTA titration.

Results

Time Hardness (°fH)

(min) Comparative experiment C Experiment 3

0 44.2 44.2

1 30.7 21 .1

2 21 .1 13.5

3 15.4 1 1 .5 5 9.6 7.7

10 7.7 7.7

15 7.7 3.8

It is clear from the results above that building Mg2+ first (with fine particles of calcium hydroxide) and Ca2+ later (with coarse particles of sodium carbonate for delayed release) reduces the water hardness better (faster and further) than building co-currently with both builder materials added as fine powders.

Example 4: Detergencv Experiments

In this experiment a tergo-to-meter was used, a commonly used small scale washing test device, consisting of a 1000 ml_ effective volume container and an agitator.

The tergo-to-meter is filled with 1000 ml_ of hard water, of 48 °fH (2:1

calcium:magnesium). The test is done at 25°C and the agitator is set to 90 rpm. Pre-stained cotton swatches (ex WFK, Germany, type WFK-10D) containing the following soil composition were used for cleaning experiments: Kaolin (10.8%), Carbon black (1 %), Iron Oxide black (0.5%), Iron Oxide yellow (0.2%) and Sebum (87.5%) The detergent composition consisted of 1 .2 g sodium carbonate, 0.15 g calcium hydroxide, 0.4 g calcite and 0.6 g NaLAS.

The wash protocol that was used was consisting of 20 min soak, 15 min wash, 2 rinses (2 min each), each step using 1000 ml_ of the hard water as defined above.

In comparative experiment D, sodium carbonate, calcite and calcium hydroxide were added together as fine powders, NaLAS was added after 5 min. The same less than 20 micrometer cut powders were used for Ca(OH)₂, calcite and Na2CO3 as in example 1 .

In experiment 4, sodium carbonate granules (0.5-2 mm cut), calcite and calcium hydroxide as powders (less than 20 micrometer cut) were added together followed by NaLAS after 5 min.

The cleaning effect was measured by a reflectance method. The reflectance values at 460 nm (R460) of the dried swatches were measured before washing and after washing with the above protocol. The difference (AR460) is a commonly used indicator for cleaning effect. The higher the AR460 number, the better the cleaning.

Results

The results show that the builder composition according to the invention also provides improved detergency in wash conditions.

Example 5: Detergency Experiments

The same protocol and conditions as in Example 4 were used.

However, the detergent composition in this experiment consisted of 1 .2 g sodium carbonate, 0.15 g calcium hydroxide, 0.4 g calcite and 0.6 g MgLAS granules (1 -2 mm granules).

In comparative experiment E, sodium carbonate, calcite and calcium hydroxide were added together as fine powders together with the MgLAS granules. The same less than 20 micrometer cut powders were used for Ca(OH)₂, calcite and Na2CO3 as above. In experiment 5, sodium carbonate granules (0.5-2 mm cut), calcite and calcium hydroxide as powders (less than 20 micrometer cut) were added together with the MgLAS granules.

Results

The results show that the experiment according to the invention is superior to the comparative example without delayed release of builder.

Claims

1 Builder composition comprising

a 5-40 parts by weight of calcium hydroxide particles having a particle size of between 1 and 20 micrometer

b 60-95 parts by weight of sodium carbonate particles having a particle size of between 200 and 2500 micrometer

2 A builder composition according to claim 1 further comprising between 1 and 35 parts of a seed material.

3 A builder composition according to claim 2 wherein the seed material is calcite.

4 Detergent composition comprising

a Between 20 and 70% by weight of the builder composition according to anyone of claims 1 to 3;

b Between 10 and 30% by weight of a surfactant; and

c Between 0 and 15% by weight of an electrolyte.

5 Method for building comprising the steps of adding between 0.1 g/L and 2.5 g/L of the builder composition according to claim 1 to water comprising hardness ions up to a hardness of between 6 and 72 °fH.

6 Use of a builder composition according to claim 1 for sequential building of

magnesium and calcium hardness ions in hard water.