The present disclosure provides a leaching process and resulting composition which prevents or substantially reduces agglomeration of polyamide 6/66 copolymers. The leaching process includes applying hot water in the presence of an agglomeration inhibitor to the polyamide 6/66 copolymers in order to separate unreacted caprolactam and small molecular weight oligomers from the copolymers while preventing or substantially reducing agglomeration of the copolymers.

A tumbler crystallizer for crystallizing pelleted, tacky, polymeric materials includes a housing for rotatably supporting a removable paneled drum on rollers. The removable panels may be made of a transparent, heat-insulating material. The drum receives a flow of hot pellets through an inlet chute, and a tumbling action of the drum and internal agitators keeps the pellets in motion relative to each other to prevent agglomeration until they reach a desired level of crystallinity and are no longer tacky. Baffle plates are provided at intervals along the length of the drum to slow the flow of pellets therethrough to increase residence time. Damper plates are provided near the exit end of the drum to aid in building a bed of pellets within the drum, and also to control residence time of the pellets within the drum.

A method for producing a polyamide resin composition containing a crystalline polyamide resin (A) containing a polycaproamide resin as a main component, a semi-aromatic amorphous polyamide resin (B), an inorganic reinforcing material (C), a master batch of carbon black (D), and a copper compound (E); a dispersion liquid of the copper compound (E) has a concentration of 0.04% by mass to 1.0% by mass; and the crystalline polyamide resin (A) containing a polycaproamide resin as a main component, the semi-aromatic amorphous polyamide resin (B), the master batch of carbon black (D), and the dispersion liquid of the copper compound (E) are mixed in advance, followed by charging the mixture is into a hopper part of an extruder, and charging the inorganic reinforcing material (C) into the extruder by a side feed method.

A method for producing a polyamide resin composition containing a crystalline polyamide resin (A) containing a polycaproamide resin as a main component, a semi-aromatic amorphous polyamide resin (B), an inorganic reinforcing material (C), a master batch of carbon black (D), and a copper compound (E); a dispersion liquid of the copper compound (E) has a concentration of 0.04% by mass to 1.0% by mass; and the crystalline polyamide resin (A) containing a polycaproamide resin as a main component, the semi-aromatic amorphous polyamide resin (B), the master batch of carbon black (D), and the dispersion liquid of the copper compound (E) are mixed in advance, followed by charging the mixture is into a hopper part of an extruder, and charging the inorganic reinforcing material (C) into the extruder by a side feed method.

A method of synthesizing polyamide microparticles may comprise: dehydrating and shearing a mixture comprising a matrix fluid, an emulsion stabilizer at about 0.01 wt % to about 50 wt % based on the weight of the matrix fluid, a solvent at about 13 wt % to about 75 wt % based on the weight of the matrix fluid, and a cyclic amide monomer at about 20 wt % to about 90 wt % based on the weight of the matrix fluid to yield an emulsion having a water content of about 1 wt % or less based on the total weight of the emulsion; adding a deprotonating agent to the emulsion at a concentration of about 0.01 wt % to about 1 wt % based on the weight of the matrix fluid; and contacting the emulsion with a polymerization initiator under conditions effective to polymerize the cyclic amide monomer into a plurality of polyamide microparticles.

A method of synthesizing polyamide microparticles may comprise: dehydrating and shearing a mixture comprising a matrix fluid, an emulsion stabilizer at about 0.01 wt % to about 50 wt % based on the weight of the matrix fluid, a solvent at about 13 wt % to about 75 wt % based on the weight of the matrix fluid, and a cyclic amide monomer at about 20 wt % to about 90 wt % based on the weight of the matrix fluid to yield an emulsion having a water content of about 1 wt % or less based on the total weight of the emulsion; adding a deprotonating agent to the emulsion at a concentration of about 0.01 wt % to about 1 wt % based on the weight of the matrix fluid; and contacting the emulsion with a polymerization initiator under conditions effective to polymerize the cyclic amide monomer into a plurality of polyamide microparticles.

The present invention relates to a composite semipermeable membrane including a supporting membrane and a separation functional layer disposed on the supporting membrane, in which the separation functional layer comprises an aromatic polyamide, the aromatic polyamide has side chains and terminal groups, at least one of the side chains and terminal groups of the aromatic polyamide being an amino group, at least one of the side chains and terminal groups of the aromatic polyamide is a substituent having a structure represented by formula (1): —NXY or formula (2): —NXYZ, and in the aromatic polyamide, a content A of substituents having structures represented by formula (1) and formula (2) and a content B of amide groups satisfy 0.005≦A/B≦0.15.

The present invention relates to a composite semipermeable membrane including a supporting membrane and a separation functional layer disposed on the supporting membrane, in which the separation functional layer comprises an aromatic polyamide, the aromatic polyamide has side chains and terminal groups, at least one of the side chains and terminal groups of the aromatic polyamide being an amino group, at least one of the side chains and terminal groups of the aromatic polyamide is a substituent having a structure represented by formula (1): —NXY or formula (2): —NXYZ, and in the aromatic polyamide, a content A of substituents having structures represented by formula (1) and formula (2) and a content B of amide groups satisfy 0.005≦A/B≦0.15.

The polyamide production method of the present invention comprises the steps of: producing a low-order condensate by effecting a polycondensation reaction between a dicarboxylic acid component containing between about 5 and about 40 mol. % of terephthalic acid, and a diamine component containing between about 70 and about 100 mol. % of a xylylenediamine in which the content of paraxylylenediamine is between about 50 and about 100 mol. %, under conditions of a reaction temperature of at least about 200° C. and less than about 230° C.; discharging and cooling the low-order condensate at a pressure at or below atmospheric pressure, in an inert gas atmosphere; and subjecting the discharged and cooled low-order condensate to solid state polymerization. The production method makes it possible to obtain a polyamide having outstanding mechanical strength, heat resistance, color tone and the like without problems such as gelling.

Described herein are methods of lowering the endotoxin content from a polyanionic polymer conjugate. In particular, methods of reducing the endotoxin content from a polyanionic polymer conjugate that can be useful for a variety of drug delivery applications are described herein.