Polyadipyl-isophthalenedimethylamine

1. Introduction to polyadipyl-isophthalenedimethylamine
Polyadipylisophthalenedimethylamine, referred to as MXD6 in English and generally referred to as "nylon MXD6", is a special high-barrier nylon material. Although MXD6 is slightly less barrier than PVDC and EVOH, its barrier properties are not affected by temperature and humidity, which is especially suitable for use in high temperature and humidity environments. In today's barrier packaging and the general trend of replacing steel with plastic, nylon MXD6 has become one of the eye-catching new plastic varieties.
2. Structural performance
(1) General performance MXD6 is a crystalline aromatic nylon, compared with other nylons, its water absorption rate is low, and the size change after water absorption is small. The molding shrinkage is low, which is suitable for the processing of precision products.
(2) Mechanical and thermal properties MXD6 has excellent mechanical and thermal properties, its mechanical strength and heat deflection temperature are high, and the linear expansion coefficient is small. After glass fiber reinforcement, the mechanical properties can also be greatly improved. The mechanical properties are less affected by temperature and can maintain high strength and rigidity over a wide range of temperatures, and the mechanical properties are less affected by humidity than other nylons.
(3) Barrier performance MXD6 has a transmittance coefficient of 2~5 (cm3) for O2, a transmittance coefficient of 28 (cm3) for CO2, and a transmittance coefficient of 15~30 (g) for H2O.
At room temperature and low relative humidity, the barrier property of MXD6 is not as good as EVOH and PVDC, but with the increase of temperature and humidity, its barrier performance does not decrease as fast as EVOH and PVDC, that is, at high temperature and high humidity, the barrier property of MXD6 is close to them.
Since MXD6 and PET are very close in terms of thermal properties such as melting point and glass transition temperature, they are very easy to form alloys. In PET, MXD6 contains 10%, its barrier performance is 2 times higher, and the tear strength, pressure resistance and transparency are comparable to those of pure PET single-layer bottles, and when MXD6 and PET are compounded to produce carbonated beverage bottles, when the MXD6 layer is 6% of the total thickness, the storage time of retaining 85% of the carbonic acid is 245 days, while that of pure PET bottles is only 84 days.
3. Scope of application
Automotive is expected to be the largest market for MXD6, followed by barrier packaging materials.
(1) Packaging materials
Food packaging is mainly made in the form of PET/MXD6 blend, which is used for the packaging of wine, beverages, pharmaceuticals and food.
Upholstery material is used for shockproof packaging of precision instruments, meters and valuables.
(2) Engineering structural materials
In auto parts, many occasions require material products with high mechanical strength and good oil resistance, and can be used for a long time in the range of 120~160 °C. Glass-fiber reinforced MXD6 has a heat-resistant temperature of up to 225°C and a high strength retention rate at high temperatures, which can be used in automobile engine blocks, cylinder heads, pistons, synchronous gears, etc.
MXD6/PPO alloy has high temperature resistance, high strength, oil resistance, wear resistance, good dimensional stability and other properties, and can be used for vertical outer panels of automobile body, front and rear fenders, wheel covers, and curved parts that can hardly be stamped and formed with steel plates and automobile chassis.
(3) Magnetic plastics The resin materials in composite magnetic plastics used to be commonly used PA6, PA66, PA12, PP, etc., but PA6 and PA12 have large water absorption, and the heat resistance after water absorption is not enough. MXD6 has low water absorption, low density, small shrinkage and high dimensional accuracy, making it an ideal composite magnetic resin material.