초록 ▼

A mixing apparatus suitable for mixing and conveying solid, particulate, polymeric materials, comprising a barrel that can be heated and cooled, at least two co-rotatable, self-wiping extruder screws located within the bore of the barrel, the screws being connected through a laterally flexible coupl

A mixing apparatus suitable for mixing and conveying solid, particulate, polymeric materials, comprising a barrel that can be heated and cooled, at least two co-rotatable, self-wiping extruder screws located within the bore of the barrel, the screws being connected through a laterally flexible coupling to a drive means which can reverse the direction of rotation of the screws upon the occurrence of a predetermined event. The apparatus also comprises a closeable feed port and a closeable discharge port, both of which can be made gas-tight, the shafts of the screws being provided with seals capable of withstanding elevated gas pressures inside the barrel.

대표청구항 ▼

[ We claim:] [1.] A process for making a high molecular weight polyamide, said process comprising(A) charging a diamine salt of a dicarboxylic acid, said salt containing at most about 1 weight percent of water, into the barrel of a mixing apparatus comprising:(a) an extruder barrel, which can be hea

[ We claim:] [1.] A process for making a high molecular weight polyamide, said process comprising(A) charging a diamine salt of a dicarboxylic acid, said salt containing at most about 1 weight percent of water, into the barrel of a mixing apparatus comprising:(a) an extruder barrel, which can be heated and cooled;(b) a closeable port for charging materials to be processed into said extruder barrel;(c) at least two meshed, co-rotatable, self-wiping extruder screws located within the bore of the barrel;(d) a drive means for the screws that is capable of reversing the direction of rotation of the screws,(e) a laterally flexible coupling connecting the drive means to the screws and capable of sustaining both thrust and tension;(f) a means for determining the occurrence of a predetermined event requiring changing the direction of rotation of the screws; and(g) a means for effecting the change of direction of rotation of the screws in response to the occurrence of said predetermined event; end of the barrel (a) proximate to the drive means (d) being sealed closed, and the opposite end of the barrel (a) being provided with a means for closing the barrel during mixing and opening it for discharging the material being processed therein;(B) in a first stage, maintaining in the barrel of the apparatus a temperature sufficient to initially cause the charge to melt but lower than the melting temperature of the product of the first stage, causing the screws to rotate repeatedly in a first direction and then in the opposite direction according to a predetermined cycling pattern, so as to mix and repeatedly convey the charge toward each end of the barrel until a solid polymeric material having lower molecular weight than the desired final polyamide has been formed;(C) in a second stage, venting the mixing apparatus and continuing to mix the charge, with or without passing a stream of an inert gas through the barrel of the apparatus, while maintaining a temperature within the barrel below the melting temperature of the desired high molecular weight polyamide product;(D) opening the discharge end of the barrel and causing the screws to rotate in the direction required to expel the charge from the barrel; and(E) collecting the so-expelled polyamide product.