Patent GB-777943-A (GB)
Title: Improved apparatus for the synthesis of polyamides
IPC: C08G69/04
Filed: 1954-01-14
Abstract: Polyamides are produced by continuously effecting a partial polymerization of at least a major portion of the starting monomer materials in a first polymerization vessel while allowing evolved gas or vapour to discharge freely, continuously adding to the product when most of the gas or vapour has evolved a viscosity stabilizer, and continuously completing the polymerization in a second vessel open to the atmosphere.  The stabilizer may be added in admixture with a low polymer prepared from the balance of the starting material.  The Specification describes four apparatuses, the monomer material being amino-undecanoic acid.  In Fig. 1 the monomer as a paste containing 45 per cent water is continuously fed at 14 to the first vessel 10 vented at 13.  A vessel 17 provided with a melting grid 19 and heated jacket 18 is charged with a separately prepared low polymer together with a stabilizer such as butyrolactone or a glycol.  Partial polymer from vessel 10 and the low polymer-stabilizer mixture from vessel 17 are continuously charged by pumps 20, 21 to a mixer 22 and thence by pump 24 to the second polymerization vessel 25 vented at 28.  The vessel 25 consists of a column provided with heating jacket 26 and baffles 27, which may be heated, to provide a tortuous path, the material flowing over the baffles in a thin layer or streams. The vessel is vented at 28. Preferably the fully polymerized material is matured in a molten state in an inert atmosphere in a vessel 29.  When the whole of the material passes through the first vessel 10 the vessel 17 may be replaced by a simple container for the liquid stabilizer.  In the apparatus of Fig. 2 the monomer is partially polymerized by passing <PICT:0777943/IV(a)/1> <PICT:0777943/IV(a)/2> <PICT:0777943/IV(a)/3> <PICT:0777943/IV(a)/4> over heated grids 42, the motion being assisted by a rotary scraper 44.  A partial polymer collects at 47, the stabilizer being added at this point from vessel 48.  In Fig. 3 the first vessel 62 is supplied with a solution or suspension of monomer by pump 61, the partial polymer being taken off at 66 to vessel 67 where it is mixed with stabilizer and low polymer from vessel 71. In the apparatus of Fig. 4 a solution or suspension of monomer is sprayed from a pipe 86 into heated grids 81.  Steam is vented at 83 and partial polymer collects at 87 where it is mixed with stabilizer and low polymer from vessel 88.  As a modification the stabilizer may be fed to the second polymerization vessel.  The starting materials may be amino acids, diamines and dibasic acids or lactams.ALSO:<PICT:0777943/III/1> <PICT:0777943/III/2> <PICT:0777943/III/3> <PICT:0777943/III/4> Polyamides are produced by continuously effecting a partial polymerization of at least a major portion of the starting monomer materials in a first polymerization vessel while allowing evolved gas or vapour to discharge freely, continuously adding to the product when most of the gas or vapour has evolved a viscosity stabilizer, and continuously completing the polymerization in a second vessel open to the atmosphere.  The stabilizer may be added in admixture with a low polymer prepared from the balance of the starting material.  The Specification describes four apparatus, the monomer material being amino-undecanoic acid.  In Fig. 1 the acimonomer as a paste containing 45 per cent water is continuously fed at 14 to the first vessel 10 vented at 13.  A vessel 17 provided with a melting grid 19 and heated jacket 18 is charged with a separately prepared low polymer together with a stabilizer such as butyrolactone or a glycol.  Partial polymer from vessel 10 and the low polymer/stabilizer mixture from vessel 17 are continuously charged by pumps 20, 21 to a mixer 22 and thence by pump 24 to the second polymerization vessel 25 vented at 28.  The vessel 25 consists of a column provided with heating jacket 26 and baffles 27, which may be heated, to provide a tortuous path, the material flowing over the baffles in a thin layer or streams.  The vessel is vented at 28.  Preferably the fully polymerized material is matured in a molten state in an inert atmosphere in a vessel 29.  When the whole of the material passes through the first vessel 10 the vessel 17 may be replaced by a simple container for the liquid stabilizer. In the apparatus of Fig. 2 the monomer is partially polymerized by passing over heated grids 42, the motion being assisted by a rotary scraper 44. A partial polymer collects at 47, the stabilizer being added at this point from vessel 48.  In Fig. 3 the first vessel 62 is supplied with solution or suspension of monomer by pump 61, the partial polymer being taken off at 66 to vessel 67 where it is mixed with stabilizer and low polymer from vessel 71.  In the apparatus of Fig. 4 a solution or suspension of monomer is sprayed from a pipe 86 into heated grids 81.  Steam is vented at 83 and partial polymer collects at 87 where it is mixed with stabilizer and low polymer from vessel 88.  As a modification the stabilizer may be fed to the second polymerization vessel.