The invention relates to a method for preparation of a polyamide 6 copolymer, characterised in that a copolymerization reaction is carried out between: o at least one caprolactam of formula (I): o at least one caprolactam, named substituted caprolactam, in which at least one of the carbon atoms is covalently linked to at least one A moiety, said A moiety being selected from the group formed of: # moieties comprising at least one group of formula: (A) #moieties comprising at least one group of formula: (B) # moieties comprising at least one group of formula: (C) The invention also relates to a polyamide 6, to polyamide 6 filaments and filaments yarns. ##STR00001##

The present specification provides a composition for interfacial polymerization of polyamide including at least one of an amine compound and an acyl halide compound; a surfactant; and a compound represented by Chemical Formula 1, and a method for preparing a reverse osmosis membrane using the same.

An antibacterial nylon 6 material of formula (I), preparation method therefor and application thereof are provided. In formula (I), each R.sub.1 group and each R.sub.2 group are independently selected from the group consisting of C.sub.1-24 linear or branched aliphatic hydrocarbyl groups, substituted or unsubstituted C.sub.3-12 alicyclic hydrocarbyl groups, substituted or unsubstituted C.sub.6-18 aryl groups and substituted or unsubstituted C.sub.7-30 aralkyl groups, or the R.sub.1 and R.sub.2 groups on the same nitrogen atom, together with the attached N atom, form a 5-7 membered saturated or unsaturated heterocyclic ring; each R.sub.3 group is independently selected from the group consisting of hydrogen (H), C.sub.1-24 linear or branched aliphatic hydrocarbyl groups, substituted or unsubstituted C.sub.3-12 alicyclic hydrocarbyl groups, substituted or unsubstituted C.sub.6-18 aryl groups, and substituted or unsubstituted C.sub.7-30 aralkyl groups; x is in a range of 0.02-0.30; y is in a range of 0.70-0.98, and x+y=1.

##STR00001##

Formulation systems usable for fabricating a three-dimensional object made of a polyamide-containing material, by three-dimensional 3D inkjet printing, and methods and systems utilizing same, are provided. The formulation systems are formed of at least a first and second model formulations containing a lactam and a catalyst for inducing anionic ring opening polymerization of the lactam in the first formulation, and an activator for promoting anionic ring opening polymerization of the lactam in the second formulation, and are further characterized as: including in the first and/or second formulation a compound capable of increasing a rate of said polymerization upon exposure to said curing energy; including as an activator a lactam-blocked polyisocyanate; and/or as including in the first model formulation at least one material capable of reducing a melting point of said first model formulation. Formulation systems usable at a selected ratio are also provided.

Formulation systems usable for fabricating a three-dimensional object made of a polyamide-containing material, by three-dimensional 3D inkjet printing, and methods and systems utilizing same, are provided. The formulation systems are formed of at least a first and second model formulations containing a lactam and a catalyst for inducing anionic ring opening polymerization of the lactam in the first formulation, and an activator for promoting anionic ring opening polymerization of the lactam in the second formulation, and are further characterized as: including in the first and/or second formulation a compound capable of increasing a rate of said polymerization upon exposure to said curing energy; including as an activator a lactam-blocked polyisocyanate; and/or as including in the first model formulation at least one material capable of reducing a melting point of said first model formulation. Formulation systems usable at a selected ratio are also provided.

The present invention relates to a method for preparing a polyamide resin, comprising the steps of: (a) preparing a polyamide polymer by anionically polymerizing a monomer including 2-pyrrolidone; (b) refining an unreacted monomer and a catalyst in the polyamide polymer with water; (c) pH-controlling through an ion exchange of the refined water; and (d) recovering the unreacted monomer by concentrating the pH-controlled water.

The present invention relates to a method for preparing a polyamide resin, comprising the steps of: (a) preparing a polyamide polymer by anionically polymerizing a monomer including 2-pyrrolidone; (b) refining an unreacted monomer and a catalyst in the polyamide polymer with water; (c) pH-controlling through an ion exchange of the refined water; and (d) recovering the unreacted monomer by concentrating the pH-controlled water.

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 Tf1Tc1 and/or between Tf2Tc2 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.

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 Tf1Tc1 and/or between Tf2Tc2 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.

To provide a method for producing a polymer, which contains: bringing a ring-opening polymerizable monomer containing an amide bond, and a compressive fluid into contact with each other to melt or dissolve the ring-opening polymerizable monomer containing an amide bond, followed by allowing the ring-opening polymerizable monomer containing an amide bond to react through ring-opening polymerization in the presence of a basic organic metal catalyst and a cocatalyst, to thereby obtain a polymer product.