Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
1999-11-23
2001-06-05
Douyon, Lorna M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S298000, C510S361000, C510S446000, C510S510000, C510S512000
Reexamination Certificate
active
06242403
ABSTRACT:
This invention relates to detergent compositions in the form of tablets for use in fabric washing. Such tablets have the advantage that they do not require the user to measure out a volume of powder or liquid. Instead one or several tablets provide an appropriate quantity of composition for washing a single load in a washing machine or possibly by hand. They are thus easier for the consumer to handle and dispense.
Detergent compositions in tablet form have been described in a number of documents and are sold commercially.
Such tablets are generally made by compressing or compacting a quantity of detergent composition in particulate form. It is desirable that tablets should have adequate mechanical strength when dry before use, yet disintegrate and disperse/dissolve quickly when added to wash water. There is difficulty in achieving both properties simultaneously. As more pressure is used when a tablet is compacted, so the tablet density and strength rise, but there is also a reduction in the speed of disintegration/dissolution when the tablet comes into contact with wash water at the time of use. Organic detergent serves as a binder, but a typical quantity of such detergent can also retard disintegration and dissolution of a tablet. Our EP-A-466485 explains that as a tablet is wetted, anionic detergent can form viscous phases which retard penetration of water into the tablet interior.
This EP-A-466485 describes detergent tablets in which anionic detergent is contained within a first particulate component of the composition. This first particulate component provides from 2 to 40% of the overall composition. In some of the examples the detergent is provided as noodles or flakes containing approximately 80 to 90% of anionic detergent in which case these noodles or flakes provide only a small percentage of the composition.
In most examples in this document the nonionic detergent was mixed with or carried in particles which provided a majority of the overall composition.
Subsequent development placed reliance on materials which were effective to promote disintegration, the organic detergent which acts as binder being present at moderate concentration in particles which provide a substantial proportion of the composition. This has led to products which are marketed commercially.
In some tablets which are currently marketed commercially, the anionic and nonionic detergent are incorporated into a spray-dried base powder which is mixed with other ingredients to form the composition stamped into tablets.
The spray-dried base powder constitutes about 40% of the composition. It contains anionic detergent as approximately 25% of the base powder and nonionic detergent as approximately 12% of the same spray-dried base powder. The other ingredients of the composition include sodium tripolyphosphate which is partially hydrated and which is rich in the Phase I form of anhydrous sodium tripolyphosphate, in accordance with the teaching of our EP-A-839906 which teaches the efficacy of this form of sodium tripolyphosphate as a way to achieve rapid disintegration. This sodium tripolyphosphate is present as just over 30% of the tablet.
In other tablets which are marketed commercially the anionic and nonionic detergent are incorporated into a granulated, non-phosphate base powder. This also constitutes slightly over 40% of the relevant composition. The balance of the composition contains a highly water soluble salt.
This is consistent with our EP-A-711827 and EP-A-838519 teach that the speed of disintegration of tablets with water-insoluble non-phosphorus builder can be accelerated by including a highly water soluble salt. Organic detergent was included as a granulated base powder. In EP-A-838519 one example of base powder contained 20% anionic detergent and 15% nonionic detergent.
We have now found good results with tablets having novel formulations which include particles which contain a relatively high concentration of organic detergent. These tablets may be either homogeneous or heterogeneous. In the present specification, the term “homogeneous” is used to mean a tablet produced by compaction of a single particulate composition, but does not imply that all the particles of that composition will necessarily be of identical composition. The term “heterogeneous” is used to mean a tablet consisting of a plurality of discrete regions, for example layers, inserts or coatings, each derived by compaction from a particulate composition. In a heterogenous tablet, each discrete region of the tablet will preferably constitute at least 10% of the overall weight of the tablet.
According to a first aspect of this invention there is provided a detergent tablet of compressed particulate composition, wherein the tablet or a region thereof comprises organic detergent and detergency builder, characterised in that the tablet or region thereof is compacted from a composition which contains:
(A) particles containing at least 60% by weight of non-soap anionic detergent
(B) particles for enhancing tablet disintegration which contain one or more water-soluble materials selected from
compounds with a water-solubility exceeding 50 grams per 100 grams water at 20° C.;
sodium tripolyphosphate containing at least 50% of its own weight of the phase I anhydrous form, and preferably partially hydrated so as to contain water of hydration in an amount which is at least 1% by weight of the sodium tripolyphosphate.
We have found that such tablets give a good combination of properties, notably strength prior to use, and rapid disintegration when placed in contact with water at the time of use.
The particles for enhancing disintegration preferably are substantially free of organic detergent, containing at most 5% of their own weight of organic detergent.
Preferably they contain at least 50%, better at least 80% of their own weight of the compound(s) with water-solubility exceeding 80 gms per 100 gm water and/or specified sodium tripolyphosphate. The balance, if any, of their content is preferably other water soluble material.
A tablet of this invention will generally contain, overall,
at least 5%, better at least 8%, up to not over 40%, possibly not over 30%, by weight of non-soap organic detergent which is preferably a combination of anionic and nonionic detergents;
at least 15%, better at least 20 or 25%, up to 80%, possibly not over 70 or 60% by weight of one or more detergency builders which may be water-soluble, water-insoluble or a mixture of soluble and insoluble builders;
optionally other ingredients which may amount to at least 10% by weight of the tablet.
Constituent materials for detergent tablets will now be discussed in more detail, and various optional and preferred features will be mentioned.
Anionic Detergent Particles
The anionic detergent particles preferably comprise from 60 to 99% by weight, more preferably from 65 to 96% by weight, of anionic detergent which is one or more a non-soap organic compounds with detersive surfactant properties.
The anionic detergent may comprise, wholly or predominantly, linear alkyl benzene sulphonate of the formula
where R is linear alkyl of 8 to 15 carbon atoms and M
+
is a solubilising cation, especially sodium.
Primary alkyl sulphate having the formula
ROSO
3
−
M
+
in which R is an alkyl or alkenyl chain of 8 to 18 carbon atoms especially 10 to 14 carbon atoms and M
+
is a solubilising cation, is also commercially significant as an anionic detergent and may be used in this invention.
Frequently, such linear alkyl benzene sulphonate or primary alkyl sulphate of the formula above, or a mixture thereof will be the desired non-soap anionic detergent and may provide 75 to 100 wt % of the anionic non-soap detergent in the particles.
Examples of other non-soap anionic detergents which may be used include olefin sulphonates; alkane sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. The anionic detergent particles may contain some nonionic detergent. The anionic detergent particles may also contain minor ingredients such as water, sodium carboxyme
Lammers Rene
Liem Seeng Djiang
Sanderson Alastair Richard
Slenderbroek Bart
Tammes Harmannus
Douyon Lorna M.
Mitelman Rimma
Unilever Home & Personal Care USA , division of Conopco, Inc.
LandOfFree
Detergent 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 Detergent compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Detergent compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2453317