Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2001-07-23
2003-04-22
Gupta, Yogendra N. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S375000
Reexamination Certificate
active
06551983
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to detergent compositions comprising bleach sensitive ingredients and a hydrogen peroxide source of a specific particle size.
BACKGROUND OF THE INVENTION
Bleach-containing detergent compositions generally contain an oxygen-based bleach, typically a perborate or percarbonate salts which releases hydrogen peroxide in the wash water, and often a bleach activator or precursor. In solid detergent compositions, these compounds are typically admixed as separate granules to the base composition.
Detergents also contain certain ingredients which are bleach-sensitive and which can react with the bleaching agent during manufacturing or storage or in use. Thus, these bleach-sensitive ingredients may loose some of their performance when present in bleach-containing compositions. For example perfumes, enzymes, dyes and brighteners can react with bleaching agent, in particular, percarbonate and perborate bleach and in particular when they are present as spray-on component or as admixed component. Various techniques are known to protect the bleach-sensitive ingredients, for example coating of these ingredients. However, there is still a need to further improve the stability of bleach-sensitive ingredients.
The inventors have now found that this problem can be reduced when particulate hydrogen peroxide sources of a specific, larger particle size and having a narrow particle size distribution are incorporated in the solid detergent compositions. It is believed that this is due to the fact that the larger particle size hydrogen peroxide sources have a smaller surface area per weight unit and thus per active oxygen or available oxygen.
There is thus a smaller total surface area per amount of active oxygen bleach in the composition, which may be in contact with the bleach-sensitive ingredients. Thus, there is a reduced possibility that the bleach-sensitive ingredients and the percarbonate or perborate are in contact and react together.
In particular in compositions whereby bleach-sensitive ingredients are present as admixed granules, or even more in compositions whereby the bleach-sensitive ingredients are sprayed onto the detergent particles, including the percarbonate, it has been found beneficial for the stability of the bleach-sensitive ingredients, that the hydrogen peroxide source has the larger particle size of the invention.
It is known that in general the larger the particle size of a particle, the slower the particle dissolves in water. Thus, this would also be expected for particulate hydrogen peroxide sources dissolve slower in water. However, the inventors have surprisingly found that the larger particle size hydrogen peroxide sources of the invention, in particular percarbonate salts, have a water-solubility which is comparable to the water-solubility of smaller sources, such as for example percarbonate salts having an average particle size of around 600 or even 500 microns.
Also, the inventors have surprisingly found that the bleaching performance of detergent compositions incorporating a hydrogen peroxide source and a bleach activator is not always satisfactory after storage, even when the bleach is stable. Also they have found that the bleaching performance may differ from one batch of product to another.
They have now found that this can be due to the segregation of the hydrogen peroxide source component in, particularly, the granular product, during manufacturing or during storage, resulting in an uneven distribution of the hydrogen peroxide source component and/or bleach activator component.
The inventors have found that it can be advantageous that the a bleach activator component, or part thereof, also has an large average particle size, preferably similar to the particle size of the hydrogen peroxide source component, to reduce the segregation of theses components in the product. Preferably, the base granules of the composition also have an average particle size similar to the particle size of the hydrogen peroxide source component and preferably the bleach activator component.
SUMMARY OF THE INVENTION
The invention provides a solid composition comprising a bleach-sensitive component and a hydrogen peroxide source wherein the hydrogen peroxide source is present in a particulate component having an average particle size, by weight, of from 700 microns to 1100 microns, preferably from 700 microns to 1000 microns, whereby at least 80% by weight of the particulate component comprising the hydrogen peroxide source has a particle size of between 60% to 140% of the of the average particle size.
Preferably, the composition comprises one or more bleach activators.
DETAILED DESCRIPTION OF THE INVENTION
Hydrogen Peroxide Source
The hydrogen peroxide source herein is present in a particulate component of the composition, preferably being admixed to the other detergent components, preferably in the form of a separate granular component of the composition. The particulate component containing the hydrogen peroxide source preferably has an average particle size of from 700 microns to 1000 microns, more preferably from 750 or even 800 microns to 950 microns or even from 820 to 920 microns.
Hereby at least 80%, preferably at least 90% or even at least 95% or even substantially 100% by weight of the particulate component comprising the hydrogen peroxide source has a particle size which is 60% to 140% of the of the weight average particle size, preferably between 70% and 130% of the weight average particle size, or even more preferably from 80% to 120% of the weight average particle size.
It may be preferred that at least 70% or even at least 80% and more preferably at least 90% or even at least 95% of the component comprising the hydroxy peroxide source has a particle size of from 600 or even 710 microns to about 1180 microns, preferably from 710 microns to 1000 microns.
Hereby it may be preferred that less than 10% by weight or even less than 6% or even less than 4% by weight has a particle size of less than 425 microns or even 600 microns. Hereby it may also be preferred that less than 10% by weight or even less than 6% or even less than 4% by weight has a particle size of more than 1400 microns or even 1180 microns.
Preferably the weight distribution of the particle sizes of the component comprising the hydrogen peroxide source is very narrowly distributed around one mean or average or median.
For example preferred may be that the weight average particle size is 800 microns, whereby (by weight) 5% or less has a particle size of less than 600 microns and less than 2% has a particle size of more than 1180 microns. Also preferred may be that the weight average particle size is 800 microns whereby (by weight) 3% or less has a particle size of less than 425 microns and less than 5% has a particle size of more than 1400 microns
The average particle size when used herein is a weight average particle size, obtained by analysing the particle size of a sample of the product by any conventional way, known in the art, for example by sieving the material through a series of sieves of given mesh sizes and measuring the weight fractions of the material which remain on the sieve and/or pass through the sieve. Minimum and maximum particle sizes are also measurable by sieving the material with sieves of a given mesh size, by ways known in the art.
Preferred hydrogen peroxide sources are perhydrate bleaches, such as metal peroxymonopersulfate, more preferably metal perborates and most preferably metal percarbonates, particularly the potassium or more preferably the sodium salts thereof.
In particular the percarbonate salts are used herein may be coated. Suitable coating agent are known in the art, for example hydrophobing agents such as wax, inorganic salts such as magnesium salts, sulphate salts and carbonates salts and silicates or mixtures thereof.
It may be preferred that the hydrogen peroxide source, and preferably the component containing it, has a solubility in water of 10° C. such that 75% of the theoretical maximum available oxygen (AvO) of said component
Hartshorn Richard Timothy
Hensman Tiffany Alice
Main Alison Lesley
Welch Robert Gary
Dressman Marianne
Gupta Yogendra N.
Petruncio John M
The Procter & Gamble & Company
Waugh Kevin L.
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