Basic reaction of AA-BB type polyamides

Polyamides can be easily moulded. They are hard and brittle and resistant to abrasion, shrinkage and heat. Certain polyamides are especially flexible and impervious to impact. Polyamides are resistant to deterioration by alkalis, petroleum products, and organic solvents. Hot phenol, formaldehydes, ultraviolet light and mineral acids destroy polyamides. Most polyamides are self-extinguishing in the event of fire. 

Polyamide is reported to be produced by seven companies in Western Europe. Overall, the Western European polyamide industry produced 1399 kilotonnes in 2002. A summary of the production data for the years 2000 - 2002 is given in Table 9.1. 

Polyamide 6 is among the most used polyamides, due to the good availability of the raw material (caprolactam), to the wide range of applications and to the production, transformation and recycling of polyamide 6 being easy and economically viable. 

Polyamide 6 can be produced both by batch or continuous polymerisation. Batch polymerisation is preferably used for changing polymer formulations with a wide range of molecular weight, mostly compounding grades. Continuous polymerisation reactors - VK columns (Vereinfacht Kontinuierlich) - have a lower range of product mix but higher productivity and are, i.e. used for the production of textile or industrial fibres. Continuous processes can be operated with one or two reactors in series. 

The main process steps used for the production of polyamide 6 are the following  

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