Abstract:
IN THE PRODUCTION OF POLYAMIDES BY PRE-CONDENSING POLYAMIDE/FORMING REACTANTS IN THE PRESENCE OF WATER, REMOVING WATER, AND THEN POLYCONDENSING TO FORM THE POLYAMIDE, THE IMPROVEMENT WHICH COMPRISES TERMINATING THE POLYCONDENSATION WHE THE VISCOSITY OF THE PRODUCT FALLS IN THE RANGE OF ABOUT 50 TO 90, TRANSFERRING THE MATERIAL AT A TEMPERATURE OF ABOUT 200 TO 300*C. TO A SCREW EXTRUDER HAVING A VACUUM OUTLET, AND ADVANCING SAID MATERIAL THROUGH THE SCREW EXTRUDER WHILE CONTAINING POLYCONDENSATION TO A FINAL ISCOSITY OF ABOUT 116 TO 150. ADVANTAGEOUSLY THE POLYAMIDE WHEN POLYCONDENSATION IS TERMINATED AT A VISCOSITY OF 50 TO 90 IS SENT TO A FEEDER BIN UNDER PRESSURE OF AN INERT GAS AND FROM THERE IS DISCHARGED INTO THE SCREW EXTRUDER. THE RESULTING POLYAMIDES, THOUGH QUITE HARD, ARE LOW MELTING AND THUS LIGHT STABLIZERS CAN BE BLENDED THEREIN AND THE EASIER WORKING WILL NOT DEGRADE THE STABILIZERS SO TRANSPARENT HOLLOW ARTICLES OF IMPROVED APPEARANCE CAN BE MADE BY INJECTION MOLDING.
Abstract:
A shock absorber piston especially suitable for use in automobiles and like vehicles wherein the piston is in contact with a damping fluid and is subject to repeated stresses under varying degrees of pressure and temperature; the piston is made of an amorphous polyamide characterized by a viscosity of about 100 to 200 in a 0.5 percent by weight solution in m-cresol at 25*C.
Abstract:
A METHOD FOR INCORPORATING GLASS PARTICLES INTO AN AMORPHOUS POLYAMIDE CONTAINING TEREPHTHALIC ACID RADICALS AND A POLYMER SELECTED FROM THE GROUP CONSISTING OF 2,2,4-TRIMETHYLHEXAMETHYLENE DIAMINE AND 2,4,4-TRIMETHYLHEXAMETHYLENE DIAMINE WHICH PROCESS COMPRISES INTRODUCING SAID POLYAMIDE AND SAID GLASS PARTICLES INTO A ZONE AND KNEADING THEM TOGETHER, PREFERABLY BY EMPLOYING A SCREW EXTRUDER SUCH AS A DOUBLE SCREW EXTRUDER UNTIL THE GLASS PARTICLES ARE INTIMATELY INCORPORATED WITHIN AND DISTRIBUTED THROUGHOUT SAID POLYAMIDE.
Abstract:
Polyamides, removed from terephthalic acid or from the dimethylester of terephthalic acid and mixtures of 2,2,4- and 2,4,4-trimethylhexamethylene diamine, sometimes adhere to the mold when injection molded. The tendency is overcome by mixing the polyamide with about 0.1 to 6 percent by weight of a lactone of three to nine carbon atoms, melting the mixture and forming it into a shaped article. The physical properties of the article are unimpaired as a result of the addition. The lactones of hydroxyfatty acids are preferred.
Abstract:
MOLDING COMPOSITIONS AMENABLE TO BLOW MOLDING, HAVING HIGH DIMENSIONAL STABILITY. THE COMPOSITION COMPRISE:
(A) TACTIC VINYL CHLORIDE POLYMERIZATE, (B) A MINOR PROPORTION OF A COPOLYMER OF VINYL CHLORIDE AND FUMARIC ACID DIESTER OR POLYMETHACRYLIC ACID ALKYL ESTER.
Abstract:
SHAPED ARTICLES OF AMORPHOUS POLYAMIDES HAVE THEIR GAS AND WATER VAPOR PERMEABILITY REDUCED BY IMMERSION IN A 45-80:55-20 WATER-COPOLYMER DISPERSION, THE COPOLYMER COMPRISING 85-90:15-10 VINYLIDENE CHLORIDE: ETHYL ACRYLATE, ALL BY WEIGHT, FOLLOWED BY DRYING IN WARM AIR. THE AMORPHOUS POLYAMIDE PREFERABLY COMPRISES RADICALS OF TEREPHTHALIC ACID, ISOPHTHALIC ACID OR MIXTURES THEREOF AND RADICALS OF 2,2,4-TRIMETHYLHEXAMETHYLENEDIAMINE, 2,4,4-TRIMETHYLHEXAMETHYLENEDIAMINE, HEXAMETHYLENEDIAMINE, NONAMETHYLENEDIAMINE OR MIXTURES THEREOF; THE SHAPED ARTICLE MAY ALSO COMPRISE UP TO ABOUT 40% BY WEIGHT OF A PARTIALLY CRYSTALLIZABLE POLYAMIDE.