Compositions – Solids with solution or dispersion aids
Reexamination Certificate
1999-12-09
2001-07-10
Lovering, Richard D. (Department: 1712)
Compositions
Solids with solution or dispersion aids
C424S489000, C424S501000, C426S098000, C510S446000, C514S941000, C514S952000, C516S099000, C516S108000
Reexamination Certificate
active
06258297
ABSTRACT:
The present invention relates to water-redispersible granules comprising an active ingredient in liquid form, a process for the preparation thereof and the use thereof.
In some industries, such as the food, cosmetics or paint industries, formulations are prepared from active ingredients in the form of a hydrophobic liquid. One formulation possibility is to prepare oil-in-water emulsions of such ingredients.
However, such emulsions cause stability problems on storage. The phases of the emulsion constituents are seen to separate to a greater or lesser extent. Further, there may be problems with deactivation of the active ingredient to contend with, the active ingredient possibly degrading by hydrolysis during storage.
Finally, the fact that in order to be readily manipulatable and pumpable, such formulations must contain relatively low quantities of active ingredient and a large amount of water cannot be ignored.
The present invention aims to provide an original alternative to the problems mentioned above in that the formulations proposed are powders containing high concentrations of active ingredient initially in the form of a hydrophobic liquid.
The invention thus provides water-redispersible granules comprising:
at least one active ingredient in the form of a hydrophobic liquid;
at least one non ionic surfactant selected from polyoxyalkylene derivatives;
at least one hydrosoluble compound selected from polyelectrolytes from the weak polyacid family.
The invention also provides a process for preparing such granules consisting of carrying out the following steps:
preparing an emulsion in water of at least one active ingredient, at least one non ionic surfactant, and at least one hydrosoluble compound;
drying the emulsion obtained
The granules of the present invention have the following advantages.
Firstly, their conformation can avoid all of the problems of using emulsions. Thus problems of instability on storage are avoided, such as creaming, flocculation, ageing and coalescence. These different phenomena have been described in the “ENCYCLOPEDIA OF EMULSIONS TECHNOLOGY”, volume 1, by Paul BECHER published by MARCEL DEKKER INC., 1983.
A further advantage of the present invention is that the concentrations of active ingredients can be very high compared with emulsions. As a result, during use of these granules, a smaller quantity of granules will suffice.
Further, the conformation of the invention can overcome the problem of deactivation of the active ingredient when it is sensitive to hydrolysis.
The present invention can also provide a pre-formulation in the form of granules which are thus easier to use than emulsions, for example in the case where the pre-formulation is added to a powder formulation.
Further, the granules of the invention, prepared from an emulsion, have the advantage of redispersing spontaneously in water, to produce again an emulsion with a granulometry close to that of the initial emulsion.
Finally, the present invention provides a solution to the problems of liquid product conformations which are normally formulated by absorption on a support. The concentration of active ingredient in such formulations is often low and there may be phase separation between the support and the active ingredient by migration of the active ingredient during storage.
Further advantages and characteristics will become more clear from the following description and examples.
As indicated above, the granules of the invention comprise at least one active ingredient in the form of a hydrophobic liquid.
All active ingredients are suitable provided that at ambient temperature they are in the form of a liquid which is non miscible in or very slightly miscible with water or are dissolved in an organic solvent.
The term “slightly miscible” means active ingredients with a solubility in water not exceeding 10% by weight.
The term “active ingredient” means either pure active ingredient or active ingredient dissolved in a solvent, or a solvent
Examples of active ingredients in the food industry are mono-, di- and tri-glycerides, essential oils, flavourings, and colorants.
Examples of active ingredients in the cosmetics industry are silicone oils, for example from the dimethicone family.
Examples of active ingredients suitable for implementing the invention in the paint industry are alkyl resins, epoxy resins, and block or non blocked isocyanates.
In the paper industry, examples are sizing resins and water repelling resins such as alkylketene dimer (AKD) or alkenyl succinic anhydride (ASA).
In the detergent industry, silicone antifoaming agents can be mentioned as active ingredients.
It is also possible to use active ingredients such as lubricants for working or deforming materials.
When the active ingredient is a solvent or a mixture of solvents, solvents are used which are non miscible in or slightly miscible with water, as defined above. Solvents which can be used are those used for cleaning or stripping, such as aromatic petroleum cuts, terpene compounds such as D-limonene, or L-limonene, also solvents such as Solvesso®. Aliphatic esters such as methyl esters of a mixture of acetic, succinic and glutaric acids (the acid mixture is a by-product of Nylon synthesis), oils such as vaseline oil, and chlorinated solvents are also suitable as solvents.
This list is, of course, given by way of indication only and is not exhaustive.
The active ingredients can be used as they are or in the presence of an organic solvent. More particularly, this solvent is selected from products which are insoluble in or slightly miscible with water.
Examples are mineral oils, mono-, di- and tri-glycerides of saturated or unsaturated fatty acids; they may be natural or synthetic triglycerides, aromatic petroleum cuts, terpene compounds (D-limonene, L-limonene), aliphatic esters or chlorinated solvents.
The granules of the invention also comprise at least one non ionic surfactant selected from polyoxyalkylene derivatives.
More particularly, the following can be cited:
ethoxylated or ethoxy-propoxylated fatty alcohols;
ethoxylated or ethoxy-propoxylated triglycerides;
ethoxylated or ethoxy-propoxylated fatty acids;
ethoxylated or ethoxy-propoxylated sorbitan esters;
ethoxylated or ethoxy-propoxylated fatty amines;
ethoxylated or ethoxy-propoxylated di(1-phenylethyl) phenols;
ethoxylated or ethoxy-propoxylated tri(1-phenylethyl) phenols;
ethoxylated or ethoxy-propoxylated alkyl phenols.
The number of oxyethylene (OE) and/or oxypropylene (OP) units in these non ionic surfactants is normally between 2 and 100 depending on the desired HLB (hydrophile/lipophile balance). More particularly, the number of OE and/or OP units is between 2 and 50. Preferably, the number of OE and/or OP units is between 10 and 50.
The ethoxylated or ethoxy-propoxylated fatty alcohols generally comprise 6 to 22 carbon atoms, OE and OP units being excluded from these numbers. These units are preferably ethoxylated units.
The ethoxylated or ethoxy-propoxylated triglycerides can be triglycerides of vegetable or animal origin (such as lard, tallow, peanut oil, butter oil, cottonseed oil, linseed oil, olive oil, fish oil, palm oil, grapeseed oil, soya oil, castor oil, rapeseed oil, copra oil, or coconut oil, and are preferably ethoxylated. The ethoxylated or ethoxy-propoxylated fatty acids are esters of fatty acids (such as oleic acid, stearic acid), and are preferably ethoxylated.
The ethoxylated or ethoxy-propoxylated esters are cyclised sorbitol esters of fatty acids containing 10 to 20 carbon atoms such as lauric acid, stearic acid or oleic acid, and are preferably ethoxylated.
The term “ethoxylated triglyceride” used in the present invention covers products obtained by ethoxylation of a triglyceride by ethylene oxide and those obtained by transesterification of a triglyceride by a polyethylene glycol.
Similarly, the term “ethoxylated fatty acid” includes both products obtained by ethoxylation of a fatty acid by ethylene oxide and those obtained by transesterification of a fatty acid by a polyethylene glycol.
The ethoxylated or ethoxy-propoxylat
Bibette Jér{dot over (o)}me
Guerin Gilles
Morvan Mikel
Chimie Rhodia
Lovering Richard D.
Seugnet Jean-Louis
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