Continuous polymerization process for polyamides
AssigneeE. I. Du Pont de Nemours and Company
InventorsAnn Marion Brearley, James Joseph Lang, Ernest Keith Andrew Marchildon
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Abstract
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.
Claims19
A continuous process for the manufacture of dimonomeric polyamide which process comprises the steps of:
- a) providing to a first reaction stage of a vertical multistage reactor, said reactor equipped with internals which enable it to cause effective contact of countercurrently flowing diamine or diamine-rich vapor with a molten acid or acid-rich process stream, having a first stage and one or more additional stages, a process stream comprising a molten diacid or a molten acid-rich mixture comprising a dicarboxylic acid and a diamine;
- b) flowing said process stream through a series of a first reaction stage and at least one more reaction stage;
- c) adding to said process stream, in at least one of the reaction stages beyond the first reaction stage, an additional diamine component as either a vapor or a diamine rich liquid;
- d) maintaining the temperature of the first reaction stage and any further stages at a sufficiently high temperature to keep solid from forming in the reaction apparatus.
A continuous process for the manufacture of dimonomeric polyamide which process comprises the steps of:
- a) providing to a first reaction stage of a vertical multistage reactor, said reactor equipped with internals which enable it to cause effective contact of countercurrently flowing diamine or diamine-rich vapor with a molten acid or acid-rich process stream, having a first stage and one or more additional stages, a process stream comprising a molten diacid or a molten acid-rich mixture comprising a dicarboxylic acid and a diamine;
- b) flowing said process stream through a series of a first reaction stage and at least one more reaction stage;
- c) adding to said process stream, in at least one of the reaction stages beyond the first reaction stage, an additional diamine component as either a vapor or a diamine rich liquid;
- d) controlling the balance of acid and amine ends in the resulting dimonomeric polyamide by an appropriate control system;
- and
- e) maintaining the temperature of the first reaction stage and any further stages at a sufficiently high temperature to keep solid from forming in the reaction apparatus.
A continuous process for preparing an essentially anhydrous mixture comprising adipic acid and hexamethylene diamine in a 75-85:15-25 weight ratio comprising the steps of:
- (a) heating a heat stable liquid to about 80.degree. C.,
- (b) adding solid adipic acid,
- (c) agitating at about 80.degree. C. until a solution is obtained,
- (d) adding hexamethylene diamine to reach the desired 75-85:15-25 by weight adipic acid:hexamethylene diamine ratio,
- (e) heating the mixture to about 120.degree. C. to about 135.degree. C., with agitation, while allowing any water present to evaporate to form an essentially anhydrous molten acid-rich mixture comprising 75-85:15-25 by weight adipic acid:hexamethylene diamine, and
- (f) feeding adipic acid and hexamethylene diamine in an 75-85:15-25 ratio to the molten acid rich mixture at the same rate that molten acid-rich feed is withdrawn.
Dependencies are inferred from the claim text.