E.i. Dupont De Nemours and Company

Invista North America S.a.r.l.

Dupont Canada Inc.

Ernest Keith Marchildon

Stuart Fergusson

Ahmet Turgut Mutel

Bryan D Kaushiva

Karen A Surgenor

Leo Ernest Manzer

Hari Babu Sunkara

David Neil Marks

Jeffrey David Cohen

Howard Chung-Ho Ng

Michel M Dumoulin

James Joseph Lang

Ann Marion Brearley

John Anthony Kendall

Grant R Stephenson

Ahmut Turgut Mutel

Douglas W Muzyka

A continuous process for the manufacture of a polyamide, the process comprising the steps of: (i) flowing a stream A comprising a molten dicarboxylic acid, or a molten dicarboxylic acid-rich mixture comprising a dicarboxylic acid and a diamine, through a first stage and at least one more reaction stage of a vertical multistage reactor, wherein the first stage is at the top of the reactor; (ii) counter-currently flowing a stream B comprising a diamine as either a vapor or a diamine-rich liquid through at least one of the stages below the first reaction stage of said vertical multistage reactor; (iii) accumulating a liquid phase material P comprising polyamide at and/or below the final stage of said reactor; wherein said reactor is equipped with internal features suitable for effecting contact between counter-currently flowing streams A and B; and wherein said process further comprises the step of agitating said liquid phase material P by injecting a gaseous stream C comprising steam, or at least one inert gas, or a mixture of steam and at least one inert gas into the reactor at or below the final stage of the reactor. The invention further provides a vertical multistage reactor configured to implement said process.

Continuous polyamidation process&#x2014;I

A continuous process for the manufacture of a polyamide, the process comprising the steps of: (i) flowing a stream A comprising a moltendicarboxylic acid, or a molten dicarboxylic acid-rich mixture comprising a dicarboxylic acid and a diamine, through a first stage and at least one more reaction stage of a vertical multistage reactor, wherein the first stage is at the top of the reactor; (ii) counter-currently flowing a stream B comprising a diamine as either a vapor or a diamine-rich liquid through at least one of the stages below the first reaction stage of said vertical multistage reactor; (iii) accumulating a liquid phase material P comprising polyamide at and/or below the final stage of said reactor; wherein said reactor is equipped with internal features suitable for effecting contact between counter-currently flowing streams A and B; and wherein the process further comprises controlling the viscosity of said liquid phase material P by directly controlling the chemical equilibrium of the polyamidation reaction or by controlling stream B so that the amounts of diamine and dicarboxylic acid introduced into the reactor during the process are stoichiometrically imbalanced. The invention further provides a vertical multistage reactor configured to implement said process.

Continuous polyamidation process&#x2014;II

A process for making nylon 6, in which caprolactam and water are reacted in a multistage reactive distillation column.

Process for converting caprolactam to nylon 6

Process for making Nylon 6,6 by reacting adiponitrile, hexamethylenediamine and steam in a multistage distillation column reactor.

Process for making nylon 6,6

Process for making nylon 6 in which a feed stream containing a major portion of caprolactam and/or nylon 6 prepolymer and a minor portion of aminocapronitrile is fed to a multistage reactive distillation column in which the feed stream flows countercurrently to a steam stream.

Process for the production of nylon 6

A continuous process for the polymerization of omega-aminonitriles (e.g., 6-aminocapronitriles) which is introduced at the top of a vertical multistage reactor being swept countercurrently with steam and polyamide (e.g., nylon 6) is recovered near the bottom of the vertical multistage reactor. By virtue of independent temperature control at each of the vertical stages of the multistage reactor, the polyamide recovered is typically characterized as having unreacted nitrile end groups of less than 20 gram equivalents per million grams of polyamide, and less than 25 gram equivalents of secondary amine branching per million grams of polyamide.

Continuous polymerization process for preparing polyamides from omega-aminonitriles

The invention provides a continuous process for the preparation of polyamides, equipment in which the polymerization process can be conducted, and process control methods for said polymerization process.

Continuous polymerization process for polyamides

A process for controlling the relative viscosity of synthetic yarns during production thereof. At least three pressure measurements are taken at three spaced locations in a transfer line for carrying molten polymer to a spinneret. Temperature and throughput of polymer in said transfer line are measured. An estimated relative viscosity of yarn produced by employing a predetermined correlation between pressure drop, throughput, temperature and relative viscosity is then calculated. A meaningful operating condition in the melting zone is adjusted in response to deviations in the estimated relative viscosity of said yarn from a desired relative viscosity of said yarn.

Process for controlling quality of yarns

An improved mixing apparatus involves a vessel having an interior surface in the shape of at least two intersecting conical frustums with axes parallel and substantially vertical. At least two interengaging helical screw elements are rotatably mounted within the vessel such that when co-rotated they interengage along their length and also conform to the interior surface of the vessel to effect a complete cleaning of each other and of the interior surface of the vessel. The bottom portion of the screw elements form a pressure generating zone and the upper portion of the screw elements form a mixing zone having a hollow center described by the co-rotating screw elements. In the mixing zone each screw element includes a continuous transition from a multilobal cross-section, e.g., trilobal cross-section (bounded by three equal arcs), to a circular cross-section. The circular cross-sections of the screw elements in the upper part of the mixing zone, i.e., above the liquid level, provide greater screw element-to-screw element shear than do the multilobal cross-sections of the screw elements according to the prior art. The mixing apparatus is useful, for example, for finishing high viscosity synthetic polymers such as polyamides, polyesters, etc.

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Kingston, Canada

Ernest Keith Marchildon