Compositions – Nonreactive analytical – testing – or indicating compositions
Reexamination Certificate
1999-03-03
2001-03-27
Lovering, Richard D. (Department: 1712)
Compositions
Nonreactive analytical, testing, or indicating compositions
C106S031310, C106S031330, C252S183110, C428S321500, C516S031000, C523S210000, C523S211000
Reexamination Certificate
active
06207080
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a process for homogeneously dispersing in a fluid matrix at least one reactant which is immiscible with the matrix, as well as to the products obtained by this process.
DESCRIPTION OF THE RELATED ART
The process of the present invention applies more particularly to the production of composite materials of the ink type, in which one or more reactants in the matrix display by themselves, or in combination with others, characteristics which change as a function of a predetermined external parameter, such as light radiation, in particular ultraviolet radiation, the temperature, the humidity and the magnetic field. The composition material obtained may thus serve to control a predetermined parameter using a visual signal or any other signal. In such an application, the matrix is polymerizable. These composite products must be able to be used by all the conventional means, such as paint, coating, printing in all its industrial forms, ink-spraying or aerosol spraying. It is thus necessary for the reactant(s) to be distributed very homogeneously in the fluid matrix in order to prevent the presence of agglomerates of reactant(s), which might have a negative impact on the application, or to prevent the presence of lacunae of reactant(s) in the layer applied, which would lead to defects and irregularities in the control signal of the determined parameter.
SUMMARY OF THE INVENTION
According to the present invention, a process is proposed which allows, in a fluid matrix, very homogeneous distribution of reactant(s) in particle form and which thereby makes it possible to obtain a composite material, which can be applied by all the conventional means, forming very fine films which have no identifiable lacunae of reactant(s).
The subject of the present invention is thus a process for homogeneously dispersing at least one reactant in a fluid matrix, characterized in that capsules of a first type containing the reactant(s) are prepared with a first encapsulation product and capsules of a second type containing the fluid matrix are prepared with a second encapsulation product which is compatible with the first, these two types of capsules bearing electric charges of opposite polarity, the capsules of the two types are combined by electric attraction and the first and second encapsulation products are removed so as to obtain a composite material consisting of the, fluid matrix containing the reactant(s) in homogeneous dispersion form.
The process according to the invention preferably includes the following steps:
a) the reactant(s) is(are) mixed with the first encapsulation product and, optionally, with a first solvent for the said first encapsulation product which is compatible with the said reactant(s), so as to obtain a pulverizable mixture,
b) the mixture obtained is sprayed so as to obtain capsules containing the reactant(s) and, among these capsules, the capsules of the first type having an electric charge of determined polarity are selected,
c) the fluid matrix is emulsified in the second encapsulation product, optionally in the presence of a second solvent which is capable of dissolving the said second encapsulation product and which is compatible with the fluid matrix, until matrix droplets of the desired size are formed in a continuous phase consisting of the second encapsulation product, those droplets of the emulsion which have an electric charge of opposite polarity to that of the capsules of the first type obtained in step b) are selected, the said droplets constituting the capsules of the second type in which the fluid matrix is encapsulated in a coating formed from the second encapsulation product,
d) the walls of the capsules of at least one of the two types obtained in steps b) and c) above are softened using a third solvent which is compatible with at least one of the two encapsulation products, and the two types of capsules are mixed together so as to combine, by electric attraction, the capsules of reactant(s) and the capsules of fluid matrix in a continuous phase consisting of at least one of the two encapsulation products,
e) the solvent(s) is(are) removed and the encapsulation product(s) is(are) separated from the mixture obtained in step d), so as to obtain a fluid matrix in which the reactant(s) is(are) homogeneously dispersed.
In step d), it is preferred to soften only the walls of the capsules of the first type using a solvent for the first encapsulation product. It is also preferred to use the same encapsulation product for steps a) and c) .
Within the context of the present patent application, the term “particles” will be understood to denote both solid particles and droplets of a product in liquid form.
According to the invention, the term “fluid matrix” is understood to denote a matrix consisting of a relatively viscous product capable of flowing when the vessel in which it is contained is tipped over. The matrix may consist mainly of a monomer or of a polymer of low molecular weight.
The matrix may in particular contain at least one fluid polymer; it advantageously consists, mainly, of at least one polymer containing, in its repeating unit, a cyclic group, which may be a cycloaliphatic group such as cyclohexane, a cycloalkenyl group containing one or more ethylenic-type bonds, such as pentene, or an aryl group, for instance the phenyl, naphthyl and anthracenyl groups. A polyester of an acid containing an aryl group in its main chain and of an aliphatic polyol is preferably used.
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Aimco SA ( Automatic Instant Mesures et Controle Optique)
Lovering Richard D.
Young & Thompson
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