The present invention relates to a method for continuously preparing a polyamide prepolymer, the viscosity in solution of which is comprised between 0.25 dL/g and 0.70 dL/g, as measured according to ISO 307:2007 in m-cresol at 20 C., the method being characterized in that it comprises a step of polycondensation on the basis of one or more polyamide precursor monomers, said polycondensation step being carried out in a extruder comprising at least two co-rotating conveying screws, the at least one monomer being previously added therein in solid or liquid form without being dissolved in a solvent or in water, and said polycondensation step being carried out without extracting the water formed during said polycondensation.

The present invention relates to a method for continuously preparing a polyamide prepolymer, the viscosity in solution of which is comprised between 0.25 dL/g and 0.70 dL/g, as measured according to ISO 307:2007 in m-cresol at 20 C., the method being characterized in that it comprises a step of polycondensation on the basis of one or more polyamide precursor monomers, said polycondensation step being carried out in a extruder comprising at least two co-rotating conveying screws, the at least one monomer being previously added therein in solid or liquid form without being dissolved in a solvent or in water, and said polycondensation step being carried out without extracting the water formed during said polycondensation.

A process for continuous production of partly crystalline polycondensate pellet material which comprises the step of crystallizing the pellet material in a second treatment space (6a) under fixed bed conditions by supply of energy from the exterior by means of a process gas, wherein the process gas has a temperature (T.sub.Gas), which is higher than the sum of the pellet temperature (T.sub.GR) and the temperature increase (T.sub.KR) which occurs due to heat of crystallization released hi the second treatment space (6a), i.e., (T.sub.Gas>(T.sub.GR+T.sub.KR)). The pellets at the exit from the second treatment space (6a) have an average temperature (T.sub.PH), which is 10 to 90 C. higher than the sum of the temperature of the pellets (T.sub.GR) and the temperature increase (T.sub.KR) which occurs due to heat of crystallization released in the second treatment space (6a), i.e., (T.sub.GR+T.sub.KR+90 C.)T.sub.PH(T.sub.GR+T.sub.KR+10).

The present disclosure relates to processes for producing high molecular weight polyamides from caprolactam. In particular, the present disclosure relates to processes for adding water during Solid State Polymerization (SSP) to remove residual caprolactam to form high molecular weight polyamides, e.g., Nylon 6 and Nylon 6,6 copolymers, having low residual caprolactam monomer content. The water addition step controls the SSP process for a specific time to produce polyamides with a desired molecular weight and low residual caprolactam monomer content.

The present disclosure relates to processes for producing high molecular weight polyamides from caprolactam. In particular, the present disclosure relates to processes for adding water during Solid State Polymerization (SSP) to remove residual caprolactam to form high molecular weight polyamides, e.g., Nylon 6 and Nylon 6,6 copolymers, having low residual caprolactam monomer content. The water addition step controls the SSP process for a specific time to produce polyamides with a desired molecular weight and low residual caprolactam monomer content.

Provided is a multilayer vessel excellent in gas barrier performance and transparency and its application. The multilayer vessel contains a layer (X) that contains at least one type of polyolefin resin as the major ingredient; and a layer (Y) that contains a polyamide resin (A) as the major ingredient, the polyamide resin (A) being composed of a structural unit derived from diamine, and a structural unit derived from dicarboxylic acid, 70 mol % or more of the structural unit derived from diamine being derived from metaxylylenediamine, meanwhile 30 to 60 mol % of the structural unit derived from dicarboxylic acid being derived from straight chain aliphatic ,-dicarboxylic acid having 4 to 20 carbon atoms, and 70 to 40 mol % being derived from isophthalic acid.

Provided is a multilayer vessel excellent in gas barrier performance and transparency and its application. The multilayer vessel contains a layer (X) that contains at least one type of polyolefin resin as the major ingredient; and a layer (Y) that contains a polyamide resin (A) as the major ingredient, the polyamide resin (A) being composed of a structural unit derived from diamine, and a structural unit derived from dicarboxylic acid, 70 mol % or more of the structural unit derived from diamine being derived from metaxylylenediamine, meanwhile 30 to 60 mol % of the structural unit derived from dicarboxylic acid being derived from straight chain aliphatic ,-dicarboxylic acid having 4 to 20 carbon atoms, and 70 to 40 mol % being derived from isophthalic acid.

The disclosure relates to a synthesis method of long carbon chain semi-aromatic nylon. The synthesis method comprises the following steps: mixing a wet powdery nylon salt, an antioxidant, a catalyst, a surfactant and pellets, and carrying out a one-step solid state polymerization under dynamic mixing to obtain a powdery nylon; under dynamic mixing, enabling the pellets to promote the stirring and mixing of the material and reducing material adhesion to the wall; the one-step solid state polymerization comprises a pre-solid state polymerization and a post-solid state polymerization; in the pre-solid state polymerization, ensuring the nylon salt and the prepolymer not to be molten; in the post-solid state polymerization, gradually reducing the system pressure to vacuum, and keeping the system pressure in vacuum state for at least 1 hour; the temperature of the post-solid state polymerization is not lower than the termination temperature of the pre-solid state polymerization.

The disclosure relates to a synthesis method of long carbon chain semi-aromatic nylon. The synthesis method comprises the following steps: mixing a wet powdery nylon salt, an antioxidant, a catalyst, a surfactant and pellets, and carrying out a one-step solid state polymerization under dynamic mixing to obtain a powdery nylon; under dynamic mixing, enabling the pellets to promote the stirring and mixing of the material and reducing material adhesion to the wall; the one-step solid state polymerization comprises a pre-solid state polymerization and a post-solid state polymerization; in the pre-solid state polymerization, ensuring the nylon salt and the prepolymer not to be molten; in the post-solid state polymerization, gradually reducing the system pressure to vacuum, and keeping the system pressure in vacuum state for at least 1 hour; the temperature of the post-solid state polymerization is not lower than the termination temperature of the pre-solid state polymerization.

A preparation method of a deodorizing nylon 6 fiber including providing a fabricating step of deodorizing nylon 6 chips and performing a spinning step. A porous powder of citrate is mixed with a caprolactam powder so as to obtain a raw material of a deodorizing chip. The raw material of the deodorizing chip is ground so as to obtain a size mixture of a deodorizing nylon 6. The size mixture of the deodorizing nylon 6 is polymerized so as to obtain the deodorizing nylon 6 chips. In the spinning step, a spinning material including the deodorizing nylon 6 chips is provided. The spinning material is spun so as to obtain a deodorizing nylon 6 fiber.