Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
2000-02-07
2003-07-22
Lovering, Richard D. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C424S070190, C504S363000, C510S417000, C514S846000, C514S859000, C514S943000, C514S975000, C516S022000, C516S028000, C516S105000
Reexamination Certificate
active
06596779
ABSTRACT:
The present invention relates to emulsions which remain perfectly stable over time, prepared from an emulsifier comprising at least one polyglycoside and at least one fatty alcohol, a process for stabilising the emulsions and an emulsifying agent.
Emulsions are mainly produced and used in industry as substances for consumption or for application to surfaces as carriers for water-insoluble agents. Emulsions are found in cosmetics (lotions, creams, ointments), in cooking (sauces, creams), in pharmaceuticals (ointments, creams), in paint (odour-free paint), in the road industry (emulsified tar), in agrochemicals (phytosanitary products), in detergents, in lamination, iron and steel making and in the production of various deposits (printing, adhesives, etc.).
In cosmetics and pharmaceuticals, for designing hygiene or care products, emulsions constitute an effective method of obtaining a harmonious combination of natural ingredients and different properties in a homogeneous form which is easy to use. The emulsifiers most commonly used at present are alkyl sulphates and sulphonates, alcohols, acids, ethoxylated fatty esters, fatty esters of sorbitan, etc.
Numerous phytosanitary compounds are water-insoluble and, having previously been rendered soluble in an organic solvent, they are capable of being emulsified in water at the time of use or at the moment of formulation with a suitable choice of emulsifiers.
The majority of emulsifiers are found in liquid presentations of phytosanitary products. The emulsifiable concentrate which is the commonest form and still the one most commonly used on the market at present conventionally contains 250 g/l of pesticide, for example, and 50 g/l of emulsifier. It is used by forming a fine emulsion the stability of which has to be ensured for a number of hours irrespective of temperature or the hardness of the water. Concentrated suspensions are a more recent development and correspond to the generation of formulations which allow very low doses to be applied per hectare. This is true, for example, of concentrated emulsions which contain, respectively, 400 to 600 g/l of pesticides and 50 to 100 g/l of emulsifiers. Unlike the two formulations mentioned above, microemulsions are thermodynamically stable systems which are therefore of great interest from the point of view of storage of the products.
The emulsifiers used in the phytosanitary field are essentially when speaking of anionic emulsifiers, calcium dodecyl benzenesulphonate, amine alkylarylsulphonates, ethoxylated fatty esters of alcohol phosphates or ethoxylated alkylphenols. Of the non-ionics, those most commonly used are ethoxylated alkylphenols, alcohols and ethoxylated fatty acids.
The preparation of emulsions using compositions containing polyglycosides and at least one fatty alcohol is well known (WO 92/06778, WO 96/37285, WO 95/13863, WO 98/47610, WO 97/18033, DE 196 07 977).
These emulsifying surfactants may take the form of compositions based on fatty alcohols and polyglycosides which have the advantage of being “self-emulsifying”. The term “self-emulsifying” denotes a composition which can be used to produce an emulsion simply, by mixing with gentle shaking with an aqueous phase.
However, it has been found, particularly in EP 0628305, that the use of such emulsifying compositions did not always result in emulsions which were sufficiently stable over time.
The Applicants have also found that the use of emulsifying compositions according to the prior art did not always result in emulsions which were stable in the presence of silicone oils. However, these oils are valuable because they result in emulsions which are pleasant to touch, giving good penetration and generally water-resistant.
It is therefore proposed according to the present invention to use emulsifiers based on polyglycosides and fatty alcohols to obtain stable emulsions (i.e. which do not separate out after the three months storage at 45° C.) even when using less than 5% by weight, based on the total weight of the emulsion, of these emulsifiers, even in the presence of silicone oils.
The high stability of the emulsions has been achieved by using emulsifiers based on fatty alcohol and polyglycosides containing polypentosides selected from among the polyarabinosides, and polyxylosides in specific proportions.
Moreover, the Applicants have found that the emulsions according to the invention, prepared from emulsifier based on fatty alcohol and polyglycosides, had a good suspending power, i.e. they were capable of holding solid particles in suspension, regardless of the viscosity of the emulsion.
In addition, the emulsifiers according to the invention, made up of polyglycosides and fatty alcohols, are of natural origin. They make it possible to prepare stable emulsions of totally plant origin. They do not have the drawbacks of emulsifiers based on polyoxyethylenated compounds which are capable of containing dioxane residues. They are non-irritant, non-toxic and biodegradable.
Moreover, the emulsifiers according to the invention can be used as self-emulsifying compositions.
The present invention thus relates to emulsions containing, by weight:
4.5 to 99.5% of water
0 to 95% of oil
0 to 50% of active substance
an emulsifier making up the total of 100%,
the emulsifier contains 30 to 65% by weight of at least one fatty alcohol of formula ROH, where R is a straight-chained or branched aliphatic radical, which may be saturated or unsaturated, having 1 to 4 ethylenic unsaturations, having 12 to 22 carbon atoms, the remainder consisting, except for impurities, of:
a) either a mixture of polyglycosides comprising polypentosides of formula (I):
R
1
O(P)
n1
(I)
wherein R
1
is a straight-chained or branched, saturated or unsaturated aliphatic radical having 1 to 4 ethylenic unsaturations, with 12 to 22 carbon atoms, P is the residue of a pentose selected from arabinose and xylose, n1 is between 1 and 5; and polyhexosides of formula (II):
R
2
O(H)
2
(II)
wherein R
2
is a straight-chained or branched, saturated or unsaturated aliphatic radical having 1 to 4 ethylenic unsaturations, with 12 to 22 carbon atoms, H is the residue of a hexose, n2 is between 1 and 5;
b) either a mixture of polyglycosides of formula (III):
R
3
O(G
1
)
a
(G
2
)
b
(G
3
)
c
(G
4
)
d
(G
5
)
e
(III)
wherein R
3
is a straight-chained or branched, saturated or unsaturated aliphatic radical having 1 to 4 ethylenic unsaturations and 12 to 22 carbon atoms, G
1
, G
2
, G
3
, G
4
and G
5
independently of one another are residues of an ose selected from among the hexoses and pentoses, the latter being selected from arabinose and xylose; a, b, c, d and e being equal to 0 or 1, the sum of a, b, c, d and e being at least 1
c) or a mixture of a and b
characterised by the following two features 1 and 2:
1) when the emulsifier contains polyglycosides comprising polypentosides of formula (I) and polyhexosides of formula (II), the polypentosides of formula (I) represent 66 to 100% by weight of the total polyglycosides, and the polyhexosides of formula (II) constitute 0 to 34% by weight of the total polyglycosides, when the emulsifier comprises polyglycosides of formula (III), the pentoses then constitute 66 to 100% by weight based on the total oses G
1
, G
2
, G
3
, G
4
and G
5
and the hexoses constitute from 0 to 34% by weight based on the total oses G
1
, G
2
, G
3
, G
4
and G
5
and
2-a) either the emulsifier constitutes at least 2.5% of total weight of the emulsion. The oily phase of the emulsion may thus consist of an oil selected from among:
oils of vegetable origin such as sweet almond oil, coconut oil, castor oil, jojoba oil, olive oil, rape seed oil, groundnut oil, hazel nut oil, palm oil, she a tree butter, apricot kernel oil, calophyllum oil, safflower oil, avocado oil, walnut oil, blackcurrant seed oil, wheatgerm oil, sunflower oil, corn seed oil, soya oil, cotton seed oil, alfalfa oil, barley oil, grapeseed oil, poppy oil, pumpkin oil, sesame oil, rye oil, evening primrose oil, passionflower oil, derivatives of these oils such
De Baynast Régis
Jean-Noel Bertmo
Philippe Mathaly
Véronique Dubois
Agro Industrie Recherches et Developpements
Knobbe Martens Olson & Bear LLP
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