Polycaprolactam (PA6) is an important engineering plastic, widely used in automotive, electronics, aerospace, textile and other fields. Its manufacturing method mainly involves polymerization reaction, polycondensation reaction and other chemical processes. This article will introduce the manufacturing method of polycaprolactam in detail.
I. Raw material preparation
1. Caprolactam monomer: caprolactam is the monomer of polycaprolactam, which is usually produced by adipic acid and adipic diamine through polycondensation reaction.
2. Initiator: Commonly used initiators are persulfate, benzoyl peroxide and so on.
3. Auxiliaries: such as heat stabilizers, antioxidants, etc., in order to improve the thermal stability and antioxidant properties of polycaprolactam.
II. Polymerization process
1. Add caprolactam monomer to the polymerization kettle and heat to a certain temperature.
2. Add initiator to initiate the polymerization reaction.
3. Under a certain temperature and pressure, maintain a certain reaction time, so that the monomer is fully polymerized.
4. Remove unreacted monomers and low molecular by-products by vacuum dehydration and other methods.
3. Post-processing
1. Extrude and granulate the polymerization product to obtain polycaprolactam granules.
2. The pellets are dried to remove water and other volatile substances.
3. The pellets are sieved to obtain polycaprolactam products of different particle sizes.
4. Precautions
1. Temperature and pressure need to be strictly controlled during the polymerization process to ensure the smooth progress of the reaction.
2. It is necessary to choose suitable initiators and auxiliaries according to the use and requirements of the products.
3. Attention needs to be paid to the quality and appearance of the products during the post-treatment process to ensure the performance and use value of the products.
In short, the manufacturing method of polycaprolactam involves several chemical processes, and it is necessary to strictly control the process parameters and operating conditions of each link to ensure the quality and yield of the product. At the same time, it is also necessary to continuously research and improve the manufacturing process to improve production efficiency and reduce costs to meet the growing demand of the market.
