The relative density of Nylon-12 is only 1.01-1.03, which is the smallest among all engineering plastics, which has a certain effect on reducing the weight of automobiles and reducing fuel consumption. If compared by unit volume, Nylon-12 has advantages in price and performance.
2) Melting point
The melting point of nylon 12 is 172-178°C, which is slightly lower than that of nylon 11, which can fully meet the working environment temperature requirements of automobile fuel pipes and air brake pipes.
3) Water absorption
As we all know, the biggest disadvantage of nylon products is that they have high water absorption and difficult to guarantee dimensional stability. However, due to the increase of methylene molecules in Nylon-12, the influence of hydrophilic groups is greatly reduced. Therefore, nylon 12 has the lowest water absorption rate among nylon products, which reduces the performance and size of products caused by water absorption. changes, which givesNylon-12 a great advantage. After absorbing water, the tensile strength of nylon 12 decreases very little, while nylon 66 and nylon 6 have large changes.
4) Impact strength
Impact strength is an important specification, especially for Nylon-12 tubing, which is often exposed to air. Nylon 12 was tested according to the standard at -20°C and -40°C, and there was no breakage phenomenon, which fully met the requirements for use. Nylon-12 has excellent impact resistance.
5) Low temperature performance
Nylon-12 has the lowest brittle temperature of -70 degrees Celsius, so it can be widely used in low temperature resistant parts. The table below lists the brittle temperature of nylon resins:
The influence of plasticizers on the physical properties of Nylon-12 is concentrated on the elastic modulus of the resin. There are three basic types of resins for Nylon 12, which differ primarily in their flexibility due to their plasticizer content. The elastic modulus of the resin decreases with the increase of the content of plasticizer extractable components.
7) Low wear and low friction performance
Nylon 12 has excellent low wear and friction properties and self-lubricating properties, so the friction noise of nylon 12 products is very low. The following table gives the values obtained by Taber disc test for Nylon 12 and other plastics.
8) Fuel resistance
In automobiles, the current use of oxygenated fuels, high aromatic fuels and alcohol blends can cause breakdown of many hose materials. Only nylon 11, Nylon-12 and fluorocarbon elastomers have been tested for use in this environment. Under the action of automobile fuel, all nylons will swell, resulting in dimensional changes, especially in gasoline containing methanol, nylon with a large number of amide groups, such as nylon 6, is more soluble than nylon with a small amount of amide groups, such as nylon 12 % The increase is much larger. After research, it was found that fuel oil containing 15% methanol had a great impact on nylon.
9) Resistance to zinc chloride solution
Zinc chloride can be present in the under-vehicle environment. Under certain temperature and humidity, the salt on the road reacts with the galvanized steel sheet or the zinc-containing primer to form a small amount of zinc chloride. Zinc chloride is highly corrosive, but Nylon-12 is very resistant to zinc chloride solutions. Ozone aging, ultraviolet radiation, temperature conditions, etc., will bring different degrees of damage to the parts and reduce the service life. Ozone aging does not occur due to the absence of + 2 3 2 + unsaturated double bonds that are susceptible to ozone attack in Nylon 12.
In addition, Nylon-12 has high crystallinity, high melting temperature, and good heat resistance stability. After adding a heat stabilizer, the heat resistance performance is doubled. When sunlight hits, its energy can cause chemical bonds in organic matter to break. However, the bond energies of C-H, C-O, and C-N bonds in Nylon-12 are all very large, and ultraviolet rays are not enough to destroy them, and can only destroy C-C bonds with smaller bond energy; therefore, after adding an appropriate anti-aging agent to the raw material, Nylon-12 The anti-ultraviolet performance is very excellent.