Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter
Reexamination Certificate
2001-07-11
2003-12-16
Kiliman, Leszek (Department: 1773)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Particulate matter
C428S407000, C528S312000, C528S315000, C528S323000, C525S09200D, C525S178000, C525S165000, C524S227000
Reexamination Certificate
active
06663962
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the preparation of porous powders formed of copolyesteramides and to the powders thus obtained. It concerns a synthesis of anionic type from at least one lactam and from at least one lactone. The powders obtained have a diameter of between 1 &mgr;m and 200 &mgr;m, a specific surface of between 1 and 25 m
2
/g and a melting temperature of between 80° C. and 220° C. These powders are of use in making pigment paper, that is to say structures comprising (i) a fibrous substrate and a hot melt adhesive layer and (ii) comprising these powders. A design or text is printed on this paper, the ink is retained in the porosity of the powders, this pigment paper is then pressed under hot conditions on a textile and the design or the text is transferred onto the textile. These powders are also of use in cosmetic compositions.
BACKGROUND OF THE INVENTION
Patent EP 192 515 discloses the anionic polymerization of a lactam in a solvent in the presence of an N,N′-alkylenebisamide. A polyamide powder is obtained, the melting temperature of which is that of PA 6 or PA 12, that is to say 220° C. and 180° C. respectively. The joint use of lactams 6 and 12 makes it possible to lower the melting point to approximately 140° C. where the composition with regard to lactams is 50/50. However, this temperature is sometimes too high for certain applications.
Patent EP 303 530 discloses a process very similar to the above process, the powder particles are composed of flakes and have a so-called gypsum flower structure. The melting temperature is the same as in the preceding prior art.
British Patent GB 1 099 184 from 1966 discloses the synthesis of lactam/lactone copolymers by anionic polymerization in a bulk process. The author of this patent describes these syntheses in greater detail in a series of articles in the review European Polymer Journal:
20(3), 241-247, 1984
20(6), 529-537, 1984
20(6), 539-547, 1984
20(6), 549-557, 1984
These polyesteramides obtained by these bulk processes exhibit melting points of less than 140° C. but thus have to form the subject of a treatment, such as milling, in order to be used in the powder form. This stage is expensive and does not make possible the preparation of fine powders with a diameter <50 &mgr;m. In addition, these powders do not exhibit any porosity.
Patent Application JP 08 325 406 A, published on Dec. 10, 1996, discloses particles of aliphatic esteramide copolymer by dissolution in a solvent, followed by precipitation. Particles of 0.5 to 50 &mgr;m are disclosed. However, the particle size is very dispersed and many particles are agglomerated.
SUMMARY OF THE INVENTION
It has now been found that, by copolymerizing at least one lactam and at least one lactone in a solvent medium (in which the lactam is soluble and the powders insoluble) and by anionic catalysis, powders are obtained having a diameter of between 1 &mgr;m and 200 &mgr;m, a specific surface of between 1 and 25 m
2
/g and a melting temperature of between 80° C. and 220° C. Another advantage of the process of the invention is that the particle size of the powders is very narrow, that is to say that at least 85% by number of the particles and advantageously 90% are within a range of 5 &mgr;m. Another advantage of this process is that the particles are porous. Furthermore, the presence of polycaprolactone blocks confers a biodegradable nature on the powders.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a process for the preparation of powders formed of copolyesteramides by anionic polymerization, in which at least one lactam and at least one lactone are copolymerized in solution in a solvent in the presence of a catalyst and of an activator, the solvent being a solvent of the lactam and the powders being insoluble in the solvent.
According to a first preferred form of the invention, at least two lactams and at least one lactone are copolymerized.
According to a second preferred form of the invention, the copolymerization is carried out in the presence of a finely divided organic or inorganic filler.
According to a third preferred form of the invention, the copolymerization is carried out in the presence of an N,N′-alkylenebisamide, such as ethylenebisstearamide (EBS) disclosed in EP 192 515, or generally amides of formula R1-NH—CO—R2, in which R1 can be replaced by an R3-CO—NH— or R3-O— radical and in which R1, R2 and R3 denote an aryl, alkyl or cycloalkyl radical.
The present invention also relates to powders formed of copolyesteramides comprising, in moles (the total being 100%):
1 to 98% of a lactam,
1 to 98% of another lactam,
1 to 98% of a lactone,
which have a diameter of between 1 &mgr;m and 200 &mgr;m and a specific surface of between 1 and 25 m
2
/g.
The invention also relates to the use of these various powders, in particular in pigment paper and cosmetics.
DETAILED DESCRIPTION OF THE INVENTION
Mention may be made, as examples of lactams, of those which have from 3 to 12 carbon atoms on the main ring and which can be substituted. Mention may be made, for example, of &bgr;,&bgr;-dimethylpropiolactam, &agr;,&agr;-dimethylpropiolactam, amylolactam, caprolactam, capryllactam and lauryllactam. Caprolactam and lauryllactam are advantageously used.
Mention may be made, as examples of lactones, of caprolactone, valerolactone and butyrolactone. Caprolactone is advantageously used.
As regards the solvent, it is a solvent of the lactam; in contrast, the copolyesteramide powder is insoluble in this solvent. Such solvents are mentioned in Patent EP 192 515. The solvent is advantageously a paraffinic hydrocarbon fraction with a boiling range lying between 140 and 170° C.
The catalyst is a base which is sufficiently strong to create a lactamate. Mention may be made, as examples of catalysts, of sodium, potassium, alkali metal hydrides, alkali metal hydroxides or alkali metal alkoxides, such as sodium methoxide or ethoxide.
As regards the activator, this term is thus used to denote any product capable of bringing about and/or accelerating the polymerization. Mention may be made, as examples, of lactams-N-carboxyanilides, isocyanates, carbodiimides, cyanimides, acyllactams, triazines, ureas, N-substituted imides or esters. The activator can be formed in situ; for example, an acyllactam is obtained by adding an alkyl isocyanate to the lactam.
The ratio of the catalyst to the activator, in moles, can be between 0.2 and 2 and preferably between 0.8 and 1.2. The proportion of catalyst in the lactam can be between 0.1 and 5 mol per 100 mol of monomers (lactams and lactones) and preferably between 0.3 and 1.5.
There are no restrictions on the proportions of lactam and lactone; the process operates with all proportions. However, the advantage is explained later of choosing proportions for adjusting the melting temperature.
The process can be carried out in a stirred reactor equipped with a device for heating via a jacket or a coil, with an emptying system, such as a bottom valve, and with a device for introducing the reactants which is flushed with dry nitrogen. The process can be carried out continuously or batchwise.
The process is advantageously carried out batchwise. The solvent is introduced and then, simultaneously or successively, the lactam, the catalyst, the activator and the lactone. It is recommended to introduce first the solvent and the lactam (or the lactam in solution in the solvent), then to remove any trace of water and, when the medium is completely dry, to introduce the catalyst. The traces of water can be removed by azeotropic distillation. Subsequently, the activator and the lactone are added. The process is carried out at atmospheric pressure and a temperature of between 20° C. and the boiling temperature of the solvent. The duration of the reaction depends on the temperature and decreases when the temperature increases. It is usually between 1 h and 12 h. The reaction is complete, all the monomers are consumed and constitute the copolyesteramide powder. On conclusion of the reaction, th
Guerin Roland
Le Crom Christophe
Atofina
Kiliman Leszek
Millen White Zelano & Branigan P.C.
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