Bleaching process and composition.

Field of the Invention

The present application relates to an improved process for effecting bleaching and / or removal of limestone scale on a surface.

Background of the Invention

The use of oxygenated bleaches in household surface bleaching compositions has been known for a long time and many such compositions are now available. However, a common difficulty during the formulation of such a composition is to ensure that it remains stable during storage but is sufficiently active in use. This is particularly difficult to achieve in liquid bleaching compositions. Many solutions to this problem have been proposed but most of these require the use of expensive stabilizing agents or complex formulation processes.

One solution has been to formulate liquid peroxide bleaches at pHs between about 3 and 7 to produce a stable composition, but in practice, these compositions do not provide sufficient bleaching power useful for many domestic situations. Until

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-2uauL-.i attempts have been made to date to formulate liquid peroxide bleach compositions at pHs above this range to improve bleaching power. However, they generally require expensive stabilizing compounds to prevent loss of activity after manufacturing.

Summary of the Invention

The present invention provides a peroxide bleaching product that has acceptable post-manufacturing stability but is capable of providing effective bleaching power when used by the consumer.

Commercial products capable of removing limestone scale from domestic surfaces are well known. Most of these products are made from acids that simply dissolve limestone scale. Many surfaces require both limestone removal and bleaching, but products that are truly capable of performing these two functions are not commercially available.

In addition, it would be convenient for the consumer to acquire a product that can be used either for the removal of limestone scale or for the

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-3 bleaching, as required, even when both functions are not required simultaneously.

The present invention provides a product that is capable of effective bleaching and / or removal of limestone scale from a surface.

In accordance with the invention, there is provided a process for bleaching and / or providing removal of limestone scale on a surface, the method comprises applying to the surface an aqueous composition of hydrogen peroxide or an organic peracid whose composition has a pH 2 or less and comprises a mixture of:

a) an aqueous composition comprising hydrogen peroxide or an organic peracid having a pH of more than 2, but less than 7 (hereinafter component (a)) and

b) an acidic composition (hereinafter component (b)), where components (a) and (b) are not mixed more than two hours before being applied to the surface that requires bleaching and / or limestone scale removal.

<td>The</td><td colspan="2">suitable compositions</td><td>to effect</td><td>the</td>

<td colspan="2">invention can be provided</td><td>in a</td><td>ready form</td><td>for</td>

<td>be used or,</td><td>preferably</td><td>they can</td><td>supply</td><td>how</td>

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IL. i separate components suitable for mixing by the consumer. When the compositions are suitable for mixing, they can be mixed either directly on the surface or away from the surface before application.

In accordance with a further aspect of the invention, there is provided a process for preparing a

<td></td><td>composition</td><td>aqueous bleach and / or</td><td>a</td><td>composition</td>

<td></td><td>eliminator</td><td>limestone inlays that</td><td>has</td><td>a pH of 2</td>

<td></td><td>or less than</td><td>consists of mixing:</td><td></td><td></td>

<td> 10</td><td>to)</td><td>an aqueous composition</td><td>than</td><td>understands</td>

hydrogen peroxide or an organic peracid having a pH of more than 2 but less than 7 (hereinafter component (a)) and,

b) an acidic composition (hereinafter component (b)), wherein components (a) and (b) are mixed for no more than two hours before being applied to the surface that

<td>requires the</td><td>Whitening</td><td>and / or the</td><td>elimination</td><td>of the</td>

<td>scale</td><td>limestones.</td><td></td><td></td><td></td>

<td>The</td><td>perished</td><td>organic</td><td colspan="2">are preferably</td>

<td>composed of</td><td colspan="2">the formula XC (O) OOH,</td><td>where X</td><td>is H 6</td>

<td>CH₃(CH₂)_n yn</td><td>Goes from</td><td>0 to 8,</td><td colspan="2">more preferably</td>

<td colspan="2">peracetic acid (n = 0),</td><td colspan="2">peroxypropionic acid</td><td>(n = l) or</td>

peroxy hexanoic acid (n = 4).

By acidic composition is meant in the

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-5I present a composition comprising at least one acid (in liquid or solid form), so that when mixed in suitable proportions with the aqueous composition comprising hydrogen peroxide or organic peracid, the resulting mixture has a pH of 2 or less.

Component (a) preferably comprises hydrogen peroxide or peracetic acid.

Component (b) can be a solid acidic composition (i.e. granular or powder) or, preferably, a liquid and aqueous acidic composition.

Wherein component (b) is an aqueous liquid, it preferably comprises hydrochloric acid, sulfamic acid, tartaric acid, phosphoric acid, oxalic acid, citric acid or salicylic acid; more preferably hydrochloric acid, sulfuric acid, phosphoric acid, or citric acid.

Wherein component (b) is solid and preferably comprises tartaric acid, phosphoric acid, ascorbic acid, oxalic acid, citric acid or salicylic acid;

more preferably phosphoric acid or citric acid.

According to the invention, the two can be mixed in any suitable proportions, depending on their initial concentrations, suitably, such that the finally applied mixture comprises 0.01-30% in

P1342 / 97MX weight of hydrogen peroxide or an organic peracid. Preferably, the ratio of component (a) to component (b) ranges from 10: 1 to 1:10, more preferably, from 2: 1 to 1: 2.

It is preferred that the two components (a) and (b) are mixed for no more than 10 minutes before application to the surface requiring bleaching and / or removal of limestone scale.

It is much more preferred that the two components (a) and (b),&gt; be mixed at the surface requiring bleaching and / or limestone removal, so that the improved bleaching effect can occur immediately.

In this aspect, component (a) can be applied to the surface followed by component (b) or vice versa. Alternatively (and preferably) components (a) and (b) are applied to the surface that requires bleaching and / or limestone scale removal substantially simultaneously.

In accordance with a preferred embodiment of the present invention, the concentration of hydrogen peroxide or organic peracid in the composition, immediately after mixing, ranges from 0.01 to 10% by weight. This would mean, for example, having a 1: 1 mix of component (a) and (b), than component (a) before

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-711. ... 1 mix would contain from 0.02 to 20% by weight of hydrogen peroxide or an organic peracid.

When component (a) comprises hydrogen peroxide, it is more preferred that the concentration of hydrogen peroxide in the mixture immediately after mixing should be 1.5 to 5% by weight. For example, if a 1: 1 mixture of components (a) and (b) is mixed, then component (a) should comprise from 3 to * 10% by weight of hydrogen peroxide.

The concentration of the acid in component (b) will be selected such that the pH of the mixture of components (a) and (b) will be 2 or less. In accordance with the above, this will depend on the acid selected, the proportion of components (a) and (b) to be mixed, the initial pH of component (a) and the intended pH of the mixture of components ( a) and (b).

The process of the present invention alleviates the need to use additional stabilizing components when preparing commercial products.

Compositions suitable for use in the process according to the invention may further include any other conventional additives known in the art. Examples of these include fragrances, surfactants (eg, anionic, cationic, nonionic, amphoteric, or mixtures thereof), thickeners,

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IL ... 1

i .:

dyes, sequestrants, chelating agents, germicides, preservatives, corrosion inhibitors or antioxidants. More preferably, compositions suitable for effecting the present invention will contain at least one of the following:

-an anionic surfactant (eg sodium xylene sulfonate),

-a nonionic surfactant (for example, an alkyl alcohol ethoxylate),

-a cationic surfactant (eg, a quaternary ammonium surfactant),

-a thickener (for example xanthan gum),

-a dye or colorant,

-a fragrance.

The above auxiliary components can be included in the compositions suitable for use in the process of the present invention at concentrations of from 0.01% by weight to 10% by weight. These auxiliary ingredients may be included in any component, component (a) or component (b) or both if appropriate.

In accordance with a further aspect of the present invention, the use of an aqueous composition of hydrogen peroxide or an organic peracid, the composition of which has a pH of 2 or less, is provided to eliminate

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-9UL..Í&gt;

* limestone scale on a surface or both for bleaching and for removing limestone scale from a surface.

Compositions suitable for use in the process according to the present invention can be stored in any appropriate container known in the art. For example, the two components can be stored in suitable two-compartment packages for dispatch sequentially or simultaneously.

When both components (a) and (b) are liquid, these can be more preferably stored in a two compartment dispenser, each compartment contains one component, the dispenser will be adapted to dispatch each component to a surface, either sequentially or preferably simultaneously.

In accordance with a further aspect of the invention, there is provided a two compartment dispenser comprising a first compartment containing an aqueous composition comprising hydrogen peroxide or an organic peracid and having a pH greater than 2 but less than 7;

a second compartment containing an acid component; and a dispatcher means adapted to dispatch the

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-1010 components (or a part thereof) from the compartments to a surface, either sequentially or simultaneously, to form a mixture thereof; whereby the pH of the acid component and / or of the dispensing medium is selected such that the mixture has a pH of less than 2.

Preferably, the first compartment contains an aqueous composition comprising 3 to 10% by weight of hydrogen peroxide and the second compartment 10 contains an aqueous composition comprising hydrochloric acid.

In accordance with the present invention, a process can be used to bleach and / or remove limestone scale from any domestic surface

<td> 15</td><td>adequate</td><td>resistant</td><td>to acids, for</td><td>example</td><td colspan="2">surfaces</td>

<td></td><td>ceramics</td><td>such as</td><td>The surfaces</td><td colspan="2">from the toilet or</td><td>the</td>

<td></td><td>tiles.</td><td>The invention</td><td>will be illustrated in</td><td>followed</td><td>through</td><td>the</td>

following examples.

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-11i .:

Example 1

The following two aqueous compositions are prepared.

Composition (a).

Hydrogen peroxide (35% aqueous solution)

9g

Water

Composition (b).

Hydrochloric Acid (from 36 Twaddle)

Water

The two compositions (a) and beaker and the pH composition of about 0.

The immediately and are left on surfaces produces a se

91g

5g

5g (b) are mixed in a resultant has a sample of the to the contact surfaces rinsed improved during composition that require to apply bleaching minutes. Then with water. The blended surface bleaching composition compared to any composition (a) or (b) alone when diluted with an equal volume of water.

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-12IHIL.I

EXAMPLE 2

The following compositions were prepared.

Parts by weight

Composition (a)

Hydrogen peroxide (aqueous solution at

35%)

Sodium xylene sulfonate (30%) 2.40

Hexadecyl trimethylammonium chloride (30%) 3.77

Citric acid 0.31

Fragrance0.20

Coloring0.005

Water 84,315 pH 2.6

Composition (b)

Hydrochloric Acid (from 36 Twaddle)

Trimethylammonium tallow chloride (50% in IPA / water)

Parts by weight

25.00

0.60

Tallow bis (2-hydroxyethyl) amine

Fatty alcohol ethoxylate (C12 / C14) moles)

1.20 (12

0.27

Water

72.93

Equal proportions of the two compositions are mixed to provide a composition that has an initial hydrogen peroxide concentration of 1.55% and an initial pH of approximately 0.

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-1313

Example 3

The following compositions were prepared.

Composition (a)

Hydrogen peroxide (35% aqueous solution) at

Parts by weight

9.00

Surfactants

3.77

Arquad 16/29 (AKZO)

Sodium xylene sulphonate (30%)

2.40

Citric acid (Anhydrous)

0.31

Fragrance (Parfex 43174 (Givaudan Roure))

Dye (Sandolun Turquoise EVS (Sandoz Dyes))

0.20

0.006

Water

84.31

Composition (b)

Premix

Parts by weight

Soft water

83.83

Surfactants

Arquad T-50

3.86

Ethomeen T12

8.00

Lutensol (80%)

1.78

Dye (Flexonil B2G (Hoechst)

0.0253

Main Mix

Hydrochloric Acid (36 Twaddle)

25.00

Premix

15.00

Soft water

60.00

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-14I

Equal proportions of the two compositions (a) and (b) were mixed to provide a composition

<td colspan="4">It has an initial concentration of hydrogen peroxide of 1,575% and an initial pH of less than 1.</td><td>of</td>

<td></td><td></td><td>EXAMPLE 4</td><td></td><td></td>

<td>The</td><td>improved</td><td>performance</td><td>bleach</td><td>the</td>

<td>compositions</td><td>of the</td><td>invention</td><td>was tested by</td><td>the</td>

following procedure.

Three ceramic tiles were covered with absorbent blue laboratory paper (Kimberley Clark). Three milliliters of one of the following compositions were applied to the tiles.

i) Example 1, Composition (a), diluted 50% by weight with water (1,575% by weight hydrogen peroxide);

ü) weight with water iii)

Example, Composition (b), diluted 50% in {4.5% by weight of active hydrochloric acid);

Example 1, a 1: 1 mixture of Composition (a) and Composition (b) (1,575% by weight of hydrogen peroxide and 4.5% by weight of active hydrochloric acid).

register iii) (the

The tiles were photographed every hour for any bleaching of the paper.

The mixed composition of the Compositions (a)

And (b) demonstrate good bleaching and compositions i) and ii) show little or no bleaching.

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-15LU .1.:

Example 5

The improved limestone scale dissolution performance of the compositions of the invention 5 is tested by the following procedure.

Pre-weighed 1-inch marble cubes are placed on 150-ml samples of the three compositions

<td></td><td>i), ii)</td><td>and</td><td>iii) described in the Example</td><td> 4.</td><td>The cubes</td><td>I know</td>

<td></td><td>withdraw</td><td>of</td><td>the compositions after</td><td>of</td><td>5 minutes,</td><td>I know</td>

<td> 10</td><td>they wash,</td><td>I know</td><td>dry, weigh and turn</td><td>to</td><td>place in</td><td>the</td>

original compositions. This process was repeated after 30, 60 and 120 minutes. The average weight loss (over 3 repetitions) in each composition is:

AVERAGE% OF WEIGHT LOSS

<td></td><td>0 mins.</td><td>5 mins.</td><td>30 mins.</td><td>60 mins.</td><td>120 mins.</td>

<td>Composition</td><td></td><td></td><td></td><td></td><td></td>

<td>i)</td><td> 0.0</td><td> 0.013</td><td> 0.013</td><td> 0.043</td><td> 0.06</td>

<td>ii)</td><td> 0.0</td><td> 8.09</td><td> 29.95</td><td> 38.74</td><td> 41.29</td>

<td>iii)</td><td> 0.0</td><td> 10.4</td><td> 33.13</td><td> 47.04</td><td> 50.55</td>

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