Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
1998-05-26
2001-04-24
Krynski, William (Department: 1774)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S445000, C510S426000, C510S299000, C510S434000, C510S443000, C510S444000
Reexamination Certificate
active
06221831
ABSTRACT:
TECHINCAL FIELD
The present invention relates to built particulate laundry detergent compositions containing especially high levels of surfactant while retaining free-flowing properties.
BACKGROUND
High levels of organic detergent surfactant (active) are sometimes required in laundry detergent compositions, particularly in compositions intended for washing by hand, to give effective soil removal. However, it has been found that problems of poor powder properties can be encountered in high-active compositions, for example, powder stickiness leading to agglomeration and poor flow.
Flow properties are improved by the presence of inorganic materials having a good carrying capacity for mobile organic surfactants, but the higher the intended surfactant level, the less room there is in the formulation for inorganic material.
Clearly it is preferable that the inorganic material included for this purpose should also itself have functionality, for example, as a detergency builder. However, one of the most effective and popular detergency builders, sodium tripolyphosphate, has a relatively poor carrying capacity for surfactants unless spray-dried.
In order to improve the liquid carrying capacity of particulate detergent compositions to allow a high active level, it is known in the art to include a relatively high proportion of material, typically builder material, which has a better carrying capacity than sodium tripolyphosphate. For example, zeolite may be used in this role. However, zeolite is insoluble and its presence may lead to residues on washed fabrics. The present inventors have therefore sought to provide particulate detergent compositions having a high surfactant content, yet having acceptable or good powder properties, without the need to incorporate substantial quantities of zeolite.
Traditionally detergent powders contain a base powder, prepared by spray-drying or granulation or a combination of such processes, consisting of structured particles containing all, or the major part of, the surfactant and builder in the formulation. Other ingredients not suitable for incorporation in the base powder, such as bleaches, enzymes, heat-sensitive nonionic surfactants, antiredeposition polymers, dye transfer inhibiting polymers, foam control granules, and perfumes are subsequently sprayed on to, or dry mixed with, the base powder.
The present inventors have discovered that free-flowing powders having higher surfactant to builder ratios than have previously been possible may be prepared, if the base powder is partly or wholly replaced by, or supplemented with, separate granular components in which certain ingredients are concentrated, or segregated from one another.
DEFINITION OF THE INVENTION
The present invention accordingly provides a free-flowing built particulate laundry detergent composition comprising:
(i) at least 27% by weight of non-soap organic detergent surfactant,
(ii) one or more detergency builders, but not more than 7% by weight of alkali metal aluminosilicate, the weight ratio of surfactant (i) to builder (ii) being at least 1.2:1.
DETAILED DESCRIPTION OF THE INVENTION
The compositions of the invention are characterised by good flow properties despite the high surfactant content and high ratio of surfactant to builder. This ratio is at least 1.2:1, and may be at least 1.5:1 or even higher.
The total content of non-soap surfactant in the compositions of the invention is at least 27% by weight, preferably from 27 to 50% by weight. The surfactant content is preferably at least 28% by weight, and more preferably at least 30% by weight. Compositions having a surfactant content of 35% by weight or more are of especial interest.
The surfactant (i) preferably comprises anionic surfactant, nonionic surfactant or a combination of the two. If both anionic and nonionic surfactants are present, the weight ratio of anionic surfactant to nonionic surfactant is preferably at least 1:1, and more preferably at least 1.5:1. Formulations containing anionic surfactant only, or nonionic surfactant only, are also of interest. Other surfactant types, for example, cationic, amphoteric or zwitterionic, may also be present. Examples of suitable surfactants are listed below.
Soap, if present, should not be taken into account when calculating the surfactant to builder ratio.
The builder (ii) may be any true detergency builder having a significant calcium binding capacity, whether inorganic or organic. The term builder as used herein specifically excludes alkali metal carbonates and soluble alkali metal silicates, both of which are sometimes referred to elsewhere as builders. Those materials may of course be present, but should not be taken into account when calculating the surfactant to builder ratio.
Similarly, sequestrants present in minor amounts as bleach stabilisers, for example aminophosphonates, should not be taken into account when calculating the surfactant to builder ratio.
Preferred inorganic builders are selected from alkali metal phosphates and layered silicates. The preferred alkali metal phosphate is sodium tripolyphosphate. Layered silicate is available as SKS-6 from Hoechst.
Alkali metal aluminosilicates may also be present, but only in an amount not exceeding 7% by weight. Preferred alkali metal aluminosilicates are zeolite 4A, and zeolite MAP (maximum aluminium zeolite P, as described in EP 384 070B (Unilever), available as Doucil (Trade Mark) A24 from Crosfield.
Preferred organic builders are di- and tricarboxylic acid salts, for example, citrates, more especially trisodium citrate; and polycarboxylate polymers, for example, acrylate and acrylate/maleate polymers, more especially Sokolan (Trade Mark) CP5 from BASF.
The total level of detergency builder in the compositions of the invention will generally be lower than in known formulations, for example, it may be as low as 4% by weight. However, it is preferably at least 10% by weight, more preferably at least 20% by weight, provided that the weight ratio of surfactant to builder is always at least 1.2:1.
The compositions of the present invention are in the form of free-flowing particulates or powders. Preferred compositions of the invention have a dynamic flow rate of at least 100 ml/s, preferably at least 110 ml/s and ideally at least 120 ml/s. A method for measuring dynamic flow rate is given below. It has not previously been possible to prepare compositions having such high surfactant levels and high surfactant to builder ratios that are in the form of free-flowing powders.
Compositions of the invention may have any bulk density ranging from very low to very high.
Preferred compositions of the invention have bulk densities within the range of from 300 to 1000 g/l, preferably from 350 to 1000 g/l, more preferably from 450 to 900 g/litre. High bulk density compositions (600 g/l and above) may be prepared in accordance with the invention.
Granules and Adjuncts
As previously indicated, in the compositions of the invention the base powder is partly or wholly replaced by, or supplemented with, separate granular components in which certain ingredients are concentrated and/or segregated from one another. This approach has made possible the preparation, in free-flowing powder form, of compositions which, if prepared by known methods, could only be obtained in the form of poorly flowing powders, doughs or sticky pastes.
Examples of such granules include:
granules containing a high level of anionic surfactant (“anionic granules”),
granules containing a high level of nonionic surfactant (“nonionic granules”), and
builder granules containing little or no surfactant.
Preferred compositions of the invention comprise at least one granular component selected from
(a) granules containing at least 60% by weight of anionic surfactant,
(b) granules containing at least 20% by weight of nonionic surfactant, and
(c) builder granules, optionally containing up to 10% by weight of surfactant.
Especially preferred compositions of the invention comprise at least two different granular components selected from
(a) granules containing at least 60% by we
Emery William Derek
Groot Andreas Theodorus
Instone Terry
Liem Seeng Djiang
Metcalfe Kenneth
Garrett Dawn L.
Krynski William
Lever Brothers Company Division of Conopco, Inc.
Mitelman Rimma
LandOfFree
Free flowing detergent composition containing high levels of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Free flowing detergent composition containing high levels of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Free flowing detergent composition containing high levels of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2475301