Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-05-10
2003-03-25
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S303000, C510S304000, C510S318000, C510S372000, C510S375000, C510S470000, C510S477000, C510S476000
Reexamination Certificate
active
06537958
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for preparing a peroxycarboxylic acid raw material having average mean particle size of less than 100 microns.
BACKGROUND OF THE INVENTION
Commonly encountered liquid aqueous bleaching compositions suitable for the bleaching of stains on fabrics and hard-surfaces are based on halogen bleaches, especially hypochlorite bleaches. Halogen bleaches are extremely effective bleaching agents, however they also present a number of drawbacks which can sometimes dissuade a consumer from choosing the halogen-containing product. For example halogen bleaches, especially chlorine bleaches, emit a pungent odour during and after use (e.g., on consumer hands and/or surfaces treated therewith) which some consumer find disagreeable.
Furthermore, it is known in the art halogen bleach-containing compositions (typically hypochlorite) are relatively aggressive to fabrics and may cause damage when used in relatively high concentration and/or repeated usage. In particular the consumer may perceive damage to the fabric itself (e.g. loss of tensile strength) or damage to the colour intensity of the fabric. While colour and fabric damage may be minimised by employing milder oxygen bleaches such as hydrogen peroxide, the bleach performance characteristics of such peroxygen bleaches are much less desirable than those of the halogen bleaching agents. Therefore, liquid aqueous activated peroxygen bleach-containing compositions have been developed containing activators, i.e., compounds which enhance peroxygen bleaching performance. However these bleaches do not perform as well as hypohalogen bleaches in stain removal.
It is thus an object of the present invention to provide a bleaching raw material and a bleaching composition which not only delivers effective bleaching performance, when used in laundry applications and/or in any household application (e.g. bleaching/disinfecting of hard-surfaces), but is also safe to the surfaces treated, e.g. to fabrics per se and/or colours of fabrics.
A particular problem encountered when formulating bleaching compositions, is the tendency of the bleaching raw material to chemical instability upon prolonged periods of storage. Thus it is thus a further object of the present invention to provide a bleaching raw material and a bleaching composition delivering effective bleaching performance and which are chemically stable upon prolonged periods of storage.
The raw material and compositions according to the present invention may be useful in any laundry application, e.g., as a laundry detergent or a laundry additive, and when used as a laundry pretreater. A particular advantage of the compositions of the present invention is that they are suitable for the bleaching of different types of fabrics including natural fabrics, (e.g., fabrics made of cotton, and linen), synthetic fabrics such as those made of polymeric fibres of synthetic origin (e.g., polyamide-elasthane) as well as those made of both natural and synthetic fibres. For example, the bleaching compositions of the present invention herein may be used on synthetic fabrics despite a standing prejudice against using bleaches on synthetic fabrics, as evidenced by warnings on labels of clothes and commercially available bleaching compositions like hypochlorite-containing compositions.
Another advantage of the bleaching compositions according to the present invention is that they can be used in a variety of conditions, i.e., in hard and soft water as well as when used neat or diluted. More particularly, it has been found that the liquid aqueous compositions of the present invention find a preferred application when used in their diluted form in any application and especially in any conventional laundry application. Indeed, upon dilution (typically at a dilution level of 20 ml/L or more (composition:water)) the compositions of the present invention become less acidic, e.g., from a pH of about 1.5 to about 6.5 or more. The compositions according to the present invention although delivering effective bleaching performance in their neat form surprisingly exhibit further enhanced bleaching performance in their diluted form. Actually, this “pH jump” effect allows to formulate acidic liquid aqueous compositions (i.e. pH below 7, preferably below 3 and more preferably below 2) which are physically and chemically stable upon prolonged periods of storage and which deliver outstanding bleaching performance under diluted usage conditions.
Yet another advantage of the compositions of the present invention is that they exhibit also effective stain removal performance on various stains including enzymatic stains and/or greasy stains.
SUMMARY OF THE INVENTION
According to the present invention there is provided a process for preparing solid pre-formed peroxycarboxylic acid raw material having mean average particle size of less than 100 microns wherein the peroxycarboxylic acid is ground in at least two consecutive grinding steps; step (i) and step (ii).
The present invention further encompasses a bleaching composition comprising the pre-formed peroxycarboxylic acid prepared.
DETAILED DESCRIPTION OF THE INVENTION
Process
The present invention relates to a process for preparing a pre-formed peroxycarboxylic acid (hereafter referred to as peracid) raw material having mean average particle size of less than 100 microns. The process involves grinding particles of peracid to achieve the mean average particle size as required herein. Peracids are available in numerous forms. One of the most useful forms available for use in bleaching compositions is a wet cake, consisting of peracid and water formed into a particles of approximately 0.16 mm to 1.4 mm. Whist it is possible to incorporate the wet cake into a bleaching composition, the Applicant has found that there are two problems generally associated with the size of the peracid in this form. The first problem is the appearance of the bleaching composition. Especially when the bleaching composition is in liquid form, the wet cake is easily visible to the naked eye. The Applicant has found that consumers find the appearance of the bleaching composition comprising the wet cake as unacceptable. The second problem relates to performance. One of the benefits in using peracids as bleaching agents is that they are generally less aggressive to fabrics than for example hypochlorite bleaches. How ever, the Applicant has found that if the wet cake is used in bleaching compositions to clean fabrics, the large particles of the wet cake can sometimes deposit on the fabrics, potentially causing localised colour loss/fading due to intense bleach action in that area.
The Applicant has found that by processing the peracid using the process of the present invention, relatively small particles can be achieved that are consumer acceptable and do not cause colour loss/fading.
The process of the present invention involves grinding the peracid in two consecutive steps. In the first step the peracid wet cake is ground using a silverson rotar mill, a coball mill (for example a mill based on the corundum stone) or mixtures thereof. At the end of this grinding step the peracid has been ground from a particle size of 0.16 to 1.4 mm to mean average particle size of between 100 and 200 microns. In the second step, the product of the first step is ground using a cobalt mill to the point where the peracid has a mean average particle size of less than 100 microns. In a preferred aspect the peracid has mean average particle size of from 10 to 80 microns and most preferably from 20 to 50 microns.
The peracid may be any peracid known in the art suitable for use herein. In a preferred embodiment of the present invention the peracid has the general formula
X—R—C(O)OOH
wherein R is a linear or branched alkyl chain having at least 1 carbon atom and X is hydrogen or a substituent group selected from the group consisting of alkyl, especially alkyl chains of from 1 to 24 carbon atoms, aryl, halogen, ester, ether, amine, amide, substituted phthalic amino, imide, hydroxide, sulphide,
Di Capua Gloria
Dresco Pierre Antoine
Scialla Stefano
Delcotto Gregory
Echler Sr. Richard S.
Miller Steven W.
The Procter & Gamble & Company
Zerby Kim W.
LandOfFree
Bleaching compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bleaching compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bleaching compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3037374