The difference between modified nylon PA6 and PA66 is like this
2023-06-01
There is no difference between Nylon 66 and Nylon 6 in appearance. From the perspective of performance and physical indicators: Nylon has better strength, wear resistance and hand feel than polyester, acrylic, polypropylene and other synthetic fibers, but nylon 66 is stronger than nylon 6. , better wear resistance, more delicate feel. structural difference PA6 is obtained by ring-opening polymerization of caprolactam, while PA66 is obtained by condensation polymerization of hexamethylenediamine and adipic acid. The two have the same molecular formula, but the structure is quite different. The number of hydrogen bonds of PA66 is higher than that of PA6, and the molecular force is also stronger than that of PA6, so PA66 has better thermal properties and requires higher processing temperature. PA6 has better toughness, and PA66 has better rigidity and hardness, which is also caused by the different hydrogen bonds in the molecular structure. performance difference Nylon PA66 Common nylon is a crystalline polymer. The melting point of nylon 66 reported by different grades and different test methods is between 250-271°C, the glass transition temperature (dry state) is 50°C, and the density is 1.13~1.16 grams per cubic centimeter. Because the phthalamide group in the amorphous part of nylon 66 is easy to combine with water molecules, the water absorption rate of nylon 66 is relatively high at room temperature. PA6 is a translucent or opaque milky white crystalline polymer particle with a melting point of 220°C, a thermal decomposition temperature greater than 310°C, a relative density of 1.14, and a water absorption rate (24 hours in 23°C water) of 1.8%. It has excellent wear resistance and self-lubrication High mechanical strength, heat resistance, good electrical insulation performance, excellent low temperature performance, self-extinguishing, good chemical resistance, especially excellent oil resistance. Compared with PA66, PA6 is easy to process and shape, the surface gloss of the product is good, and the service temperature range is wider, but the water absorption rate is higher and the dimensional stability is poor. It has low rigidity, low melting point, can be used for a long time in harsh environments, and can still maintain sufficient stress in a wide temperature range, and the continuous use temperature is 105°C. application difference PA6 is used in industrial fields such as electronics and automobiles. Its civilian silk industry consumes a relatively high proportion of nylon filament for clothing, about 58%. The use of PA6 in the tire frame nylon cord market accounts for about 13%. Engineering plastics use PA6 accounted for 12%, including injection plastics and modified plastics. PA6 accounts for about 6% of fishing net wire. Plastic film-grade PA6 for the production of BOPA film accounts for 4%, staple fiber PA6 for the production of carpets, sweaters, non-woven fabrics and other supplies accounts for 4%, and other PA6 for the production of PA rods, PA tapes, etc. accounts for 3%. PA66 is widely used in clothing, decoration, engineering plastics and other fields. The highest proportion of its consumption is engineering plastics, accounting for 65% of the total consumption, while industrial yarn accounts for 20%, and others account for 15% of the total consumption. Compared with nylon 6, nylon 66 has better mechanical strength, stiffness, heat resistance and wear resistance, and better creep resistance, but its impact strength and mechanical shock absorption performance are reduced. It has a wide range of applications in automobiles, drones, electronics, etc. The development of nylon 66 and nylon 6 should be fully considered from the rational use of resources. When the resources of sulfuric acid are sufficient, the application of ammonium sulfate has its market, and nylon 6 has its own advantages of priority development. It is more appropriate to develop nylon 66 in places where sulfuric acid resources are relatively scarce.
