Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2001-05-31
2003-03-04
Pezzuto, Helen L. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S307300, C526S320000, C526S321000, C526S323100, C526S336000, C526S347000
Reexamination Certificate
active
06528606
ABSTRACT:
The present invention relates to the preparation of a stable composition of radically polymerisable monomers, containing at least one monomer having urea function(s). Said composition is stable despite the joint presence within it of said monomer(s) having urea function(s) and at least one monomer of another type which is radically copolymerisable.
The present invention can also be analysed as an original method of preparing monomers having urea function(s), said monomers being, at the end of said original preparation, obtained in solution in a solvent which is constituted of at least one other radically copolymerisable monomer; the resulting composition−monomer(s) having urea function(s)+other monomer(s)−being stable.
Monomers having urea function(s) (monomers which have at least one urea function in their chemical formula) are generally prepared in order then to be copolymerised with at least one monomer of another type.
On a laboratory scale, they are generally prepared and used, as a comonomer, as soon as they are obtained.
On an industrial scale, problems of their manipulation and of their storage are more frequently come up against. With reference to these two problems, the incorporation of a solvent may be opportune, but does involve further manipulations. If they are manipulated and/or stored in the presence of at least one comonomer, the mixture has a tendency to gelify, to solidify.
Confronted with this problem of storage, and more specifically with that of the instability of the compositions based on such mixtures of monomers (compositions which contain at least one monomer having urea function(s) and at least one radically copolymerisable monomer of another type), the Applicant proposes an original solution: an original method of preparing said monomer having urea function(s) which leads to said monomer, stabilised, in solution in at least one other monomer. Furthermore, said stabilised monomer is found under interesting conditions for its future use (as a comonomer). It can be easily manipulated without it being in solution in a solvent, in the sense of the prior art.
U.S. Pat. No. 4,990,575 describes compositions which contain such monomers having urea function(s). Said monomers (ureas having isopropenylic functions) are of the formula (I) below:
They are obtained by a reaction of 3-isopropenyl-&agr;,&agr;-dimethylbenzyl isocyanate (m-TMI®), of formula:
with a polyoxyalkylenepolyamine, of formula:
In accordance with the teaching of the examples of the patent, a stoichiometric amount of m-TMI® is added slowly to the polyamines, more specifically to Jeffamines® marketed by the company Huntsman Corporation, to lead to the urea monomers sought after.
These urea monomers, which have isopropenylic functions, do not form a homopolymer by radical polymerisation but can easily be copolymerised with vinylic monomers, of the styrene, acrylate, or methacrylate type. Such copolymerisations are carried out in the presence of radical initiators. Some have been described in the Journal of Coatings Technology, Vol. 58, No. 737, June 1986.
U.S. Pat. No. 4,990,575 describes the synthesis of these urea monomers in the presence or not of a solvent such as isopropanol.
Said urea monomers are, in themselves, solid or very viscous and are therefore difficult to manipulate. Their pumping is not, in any case, an easy thing.
The solutions of these monomers are obviously easier to manipulate, but within the context of the use of said monomers as a comonomer in a copolymerisation reaction, it is necessary sooner or later to get rid of the intervening solvent, generally by evaporation. The evaporation operations do, on an industrial scale, consume much space and energy. Furthermore, they generate problems of safety and of pollution.
Further, the Applicant has described the synthesis of such urea monomers in the applications EP-A-0 977 788 and FR-A-2 783 829. The Applicant has led said synthesis on a laboratory scale, under nitrogen, in the presence of a comonomer, the reagents intervening in stoichiometric amount. The Applicant was not at the time interested in the stability of said monomers on storage. As soon as the monomers were prepared, they were copolymerised.
The Applicant presently proposes a method of preparing a composition of radically copolymerisable monomers, said composition containing firstly at least one monomer which has at least one urea function in its formula and secondly at least one monomer which does not have an isocyanate function in its formula (which monomer is sometimes qualified as <<the other monomer>> in the present text).
The method comprises:
preparing said monomer(s) having urea function(s) by reaction of two types of reagent: at least one radically copolymerisable monomer which has at least one isocyanate function in its formula with at least one amine selected from primary and secondary amines ; and
incorporating said monomer(s) which does(do) not have an isocyanate function in its(their) formula, prior to said reaction, together with one of said reagents before adding the other of said reagents, and/or during the addition of said reagents, and/or after said reaction.
Characteristically, within the context of said method:
said reaction of preparing said monomer(s) having urea function(s) is carried out in the absence of non-radically polymerisable solvent, with said reagents, monomer(s) having isocyanate function(s) and amine(s), being incorporated in relative proportions such that the isocyanate equivalent/amine equivalent ratio be between 0.98 and 1.02, and advantageously equal to 1; and
said monomer(s) having urea function(s) obtained at the end of said reaction is(are) maintained diluted in the solvent which is constituted of said monomer(s) which does(do) not have an isocyanate function in its(their) formula, in the presence of dissolved oxygen; the composition thus prepared being stable.
The method of the invention does not make use of a solvent in the sense of U.S. Pat. No. 4,990,575. However, it leads to a stable mixture of monomers which is easy to manipulate (notably easy to pump).
With reference to the stability on storage, the Applicant has demonstrated the crucial importance of the two parameters, below:
the relative proportion of the reagents in question: they must imperatively be incorporated in amounts which are close to stoichiometry, advantageously in stoichiometric amounts, and more specifically in relative proportions such that the isocyanate equivalent/amine equivalent ratio be between 0.98 and 1.02, and advantageously equal to 1. On this point, Examples 1, 1′, 1″, infra, can be considered;
the presence of dissolved oxygen in the mixture of monomers. It is recommended to incorporate said dissolved oxygen to saturation. In fact, the beneficial effect of the presence of said oxygen is generally felt as soon as said oxygen intervenes at a content of greater than 1% of the content at saturation.
With reference to the convenience of manipulation, the Applicant recommends the incorporation, at least for the storage, even for later on (for the implementation of the reaction), of an entirely original solvent: at least one other radically copolymerisable monomer which does not have an isocyanate function in its formula. The incorporation of said other monomer must not disrupt the relative proportions set forth supra. The incorporation of said other monomer is particularly opportune in the hypothesis in which it constitutes afterwards a partner of copolymerisation of the urea monomer prepared according to the invention. The urea monomers are thus obtained according to the invention in solution in at least one comonomer.
In the light of the comments above, it will already have been understood that the method of the invention is analysed as a method of preparing and of storing a stable composition of specific monomers; the stability of said composition depending upon (being acquired by) the combination of the specific conditions of implementation of the synthesis reaction on the one hand, and, on the othe
Bear Marie-Maud
Lafosse Xavier
Corning S.A.
Pezzuto Helen L.
Rogalskyj Peter
Schaeberle Timothy M.
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