Abstract: A method for reducing the crystallization temperature and the melting temperature of a polyamide powder resulting from the polymerization of at least one predominant monomer, in which the reduction in the crystallization temperature is greater than the reduction in the melting temperature, the method including a step of polymerization of the at least one predominant monomer with at least one different minor comonomer polymerized according to the same polymerization process as the at least one predominant monomer, the at least one minor comonomer being chosen from aminocarboxylic acids, diamine/diacid pairs, lactams and/or lactones, and the at least one minor comonomer representing from 0.1% to 20% by weight of the total blend of the monomers(s) and comonomer(s), preferably from 0.5% to 15% by weight of the total blend, preferably from 1% to 10% by weight of the total blend.

Abstract: A method for reducing the crystallization temperature and the melting temperature of a polyamide powder resulting from the polymerization of at least one predominant monomer, in which the reduction in the crystallization temperature is greater than the reduction in the melting temperature, the method including a step of polymerization of the at least one predominant monomer with at least one different minor comonomer polymerized according to the same polymerization process as the at least one predominant monomer, the at least one minor comonomer being chosen from aminocarboxylic acids, diamine/diacid pairs, lactams and/or lactones, and the at least one minor comonomer representing from 0.1% to 20% by weight of the total blend of the monomers(s) and comonomer(s), preferably from 0.5% to 15% by weight of the total blend, preferably from 1% to 10% by weight of the total blend.

Abstract: The present invention relates to a method for reducing the crystallization temperature an the melting temperature of a polyamide powder resulting from the polymerization of at least one predominant monomer, in which the reduction in the crystallization temperature is greater than the reduction in the melting temperature, said method comprising a step of polymerization of said at least one predominant monomer with at least one different minor comonomer polymerized according to the same polymerization process as said at least one predominant monomer, said at least one minor comonomer being chosen from aminocarboxylic acids, diamine/diacid pairs, lactams and/or lactones, and said at least one minor comonomer representing from 0.1% to 20% by weight of the total blend of said monomers(s) and comonomer(s), preferably from 0.5% to 15% by weight of said total blend, preferably from 1% to 10% by weight of said total blend.

Abstract: The present invention relates to a method for reducing the crystallization temperature an the melting temperature of a polyamide powder resulting from the polymerization of at least one predominant monomer, in which the reduction in the crystallization temperature is greater than the reduction in the melting temperature, said method comprising a step of polymerization of said at least one predominant monomer with at least one different minor comonomer polymerized according to the same polymerization process as said at least one predominant monomer, said at least one minor comonomer being chosen from aminocarboxylic acids, diamine/diacid pairs, lactams and/or lactones, and said at least one minor comonomer representing from 0.1% to 20% by weight of the total blend of said monomers(s) and comonomer(s), preferably from 0.5% to 15% by weight of said total blend, preferably from 1% to 10% by weight of said total blend.

Abstract: The invention relates to a seeded particle of polyamide (PA) powder composed of a shell made of PA-6, PA-12 or PA-6/12 and of a core made from PA-6, paA-11, PA-12 or PA-6/12, PA 6,12, PA-6,6, PA-8 or PA-4, the core and the shell being either of identical polyamide nature but of different molecular weight, or of different polyamide nature. The particle for which the shell has a melting temperature Tf1 and a crystallization temperature Tc1 and for which the core has a melting temperature Tf2 and a crystallization temperature Tc2, is characterized in that the difference in absolute value between Tf1?Tc1 and/or between Tf2?Tc2 is greater than the difference in absolute values between the melting temperature and the crystallization temperature of a particle of powder seeded by a mineral filler and for which the shell is made of PA6, PA12 or PA6/12.

Abstract: The invention relates to a method for obtaining polyamide or copolyamide particles which are spheroidal and whose average diameter is between 40 and 150 ?m, preferably between 60 and 100 ?m. Said method consists of introducing a mineral charge, preferably silica, having an average diameter of 1-30 ?m into the reaction mixture. The invention also relates to a polyamide or copolyester amide powder and to the use thereof in order to manufacture coatings, ink compositions, paint compositions, cosmetic compositions, pharmaceutical compositions, alloys with metal powders or metal oxide powders and parts by agglomerating said powder by laser sintering, IR radiation or UV radiation.

Abstract: The present invention relates to a process for the preparation of polyamide-12 powder by anionic polymerization of lauryllactam in solution in a solvent of the lactam, the polyamide-12 powder being insoluble in this solvent, the polymerization being carried out: in the presence of a catalyst and of an activator; in the presence of a finely divided organic or inorganic filler, the proportion of this filler being less than or equal to 1.5 g per 1000 g of lauryllactam; and in the presence of an amide 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 proportion of this compound being between 0.001 mol and 0.030 mol per 1000 g of lauryllactam.

Abstract: The subject of the invention is a process for producing polyamide, copolyamide, polyolefin, copolyester amide or fluorocarbon resin powder particles on to the surface of which has been grafted at least one functionalized grafting monomer, characterized in that it comprises: a) a step of blending the polyamide or copolyamide powder particles with the functionalized grafting monomer; followed by b) a step of irradiating the powder impregnated with functionalized grafting monomer resulting from a) with photons (?-radiation) or electrons (?-radiation), with a dose ranging from 0.5 to 15 Mrad. The invention also relates to the particles grafted in this way and to the compositions containing such particles.

Abstract: The present invention relates to a method for reducing the crystallization temperature an the melting temperature of a polyamide powder resulting from the polymerization of at least one predominant monomer, in which the reduction in the crystallization temperature is greater than the reduction in the melting temperature, said method comprising a step of polymerization of said at least one predominant monomer with at least one different minor comonomer polymerized according to the same polymerization process as said at least one predominant monomer, said at least one minor comonomer being chosen from aminocarboxylic acids, diamine/diacid pairs, lactams and/or lactones, and said at least one minor comonomer representing from 0.1% to 20% by weight of the total blend of said monomers(s) and comonomer(s), preferably from 0.5% to 15% by weight of said total blend, preferably from 1% to 10% by weight of said total blend.

Abstract: The subject of the invention is a process for producing polyamide, copolyamide, polyolefin, copolyester amide or fluorocarbon resin powder particles on to the surface of which has been grafted at least one functionalized grafting monomer, characterized in that it comprises: a) a step of blending the polyamide or copolyamide powder particles with the functionalized grafting monomer; followed by b) a step of irradiating the powder impregnated with functionalized grafting monomer resulting from a) with photons (?-radiation) or electrons (?-radiation), with a dose ranging from 0.5 to 15 Mrad. The invention also relates to the particles grafted in this way and to the compositions containing such particles.

Abstract: The invention relates to a method for preparing a powdered polymer selected from a polyamide, a copolyamide or a copolyesteramide by anionic polymerization in a solvent solution, characterized in that the polymerization of the monomers) generating said polymer is made in the presence of a catalyst, an activator, at least one amide one of which is always a N,N?-alkylene bisamide, and an organic or inorganic filler, the amount of N,N?-alkylene bisamide added in the medium being determined based on the specific surface are desired for the powder particles, said powder particles having an essentially constant diameter or one depending on the desired mean diameter of the powder particles, said powder particles having an essentially constant specific surface area.

Abstract: The invention relates to a seeded particle of polyamide (PA) powder composed of a shell made of PA-6, PA-12 or PA-6/12 and of a core made from PA-6, paA-11, PA-12 or PA-6/12, PA 6,12, PA-6,6, PA-8 or PA-4, the core and the shell being either of identical polyamide nature but of different molecular weight, or of different polyamide nature. The particle for which the shell has a melting temperature Tf1 and a crystallization temperature Tc1 and for which the core has a melting temperature Tf2 and a crystallization temperature Tc2, is characterized in that the difference in absolute value between Tf1?Tc1 and/or between Tf1?Tc2 is greater than the difference in absolute values between the melting temperature and the crystallization temperature of a particle of powder seeded by a mineral filler and for which the shell is made of PA6, PA12 or PA6/12.

Abstract: The invention relates to a method for obtaining polyamide or copolyesteramide particles which are spheroidal and whose average diameter is between 40 and 150 ?m, preferably between 60 and 100 ?m. Said method consists in introducing a mineral charge, preferably silica, having an average diameter of 1-30 ?m into the reaction mixture. The invention also relates to a polyamide or copolyesteramide powder and to the use thereof in order to manufacture coatings, ink compositions, paint compositions, cosmetic compositions, pharmaceutical compositions, alloys with metal powders or metal oxide powders and parts by agglomerating said powder by laser sintering, IR radiation or UV radiation.

Abstract: The subject of the invention is a process for producing polyamide, copolyamide, polyolefin, copolyester amide or fluorocarbon resin powder particles on to the surface of which has been grafted at least one functionalized grafting monomer, characterized in that it comprises: a) a step of blending the polyamide or copolyamide powder particles with the functionalized grafting monomer; followed by b) a step of irradiating the powder impregnated with functionalized grafting monomer resulting from a) with photons (?-radiation) or electrons (?-radiation), with a dose ranging from 0.5 to 15 Mrad. The invention also relates to the particles grafted in this way and to the compositions containing such particles.

Abstract: The present invention relates to a process for the preparation of polyamide-12 powder by anionic polymerization of lauryllactam in solution in a solvent of the said lactam, the polyamide-12 powder being insoluble in this solvent, the said polymerization being carried out: in the presence of a catalyst and of an activator; in the presence of a finely divided organic or inorganic filler, the proportion of this filler being less than or equal to 1.5 g per 1000 g of lauryllactam; and in the presence of an amide 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 proportion of this compound being between 0.001 mol and 0.030 mol per 1000 g of lauryllactam.