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Polyamide (PA), commonly known as nylon, is a general term for resins containing repeating amide groups - NHCO - on the molecular chain, obtained by condensation of binary acids with diamines or amino acids. Nylon is the foundation resin with the largest production, most varieties, widest use, and excellent comprehensive performance among the five general engineering plastics.

Nylon, as an important engineering plastic today, is constantly being modified through physical and chemical means to achieve high performance. At present, many fields have put forward new requirements for the high-temperature resistance function of materials. In order to adapt to these requirements, people have done a lot of research in the development of new high-temperature nylon products.

Definition of high-temperature nylon

High temperature nylon (HTPA) is a heat-resistant polyamide that can be used as an engineering plastic in an environment of 150 ℃ for a long time. Good performance in thermal, electrical, physical, and chemical resistance. Especially at high temperatures, it still has high rigidity and strength, as well as excellent dimensional accuracy and stability.

Characteristics of high-temperature nylon

1. High temperature resistance. The thermal deflection temperature is 280 ℃ (1.8MPa), and the continuous use temperature is 180 ℃.

2. Creep performance. The high crystallinity of HTPA allows it to maintain excellent rigidity at high temperatures (above 120 ℃), with aluminum like strength, steel like hardness, and rubber like flexibility, ductility, and impact resistance.

3. Excellent dimensional accuracy and stability. The molecular structure of HTPA contains aromatic rings in its molecular segments, making the molecular structure more regular and the chain shorter and less prone to movement.

4. Chemical resistance. Polyamide materials have good resistance to most chemicals. Like other polyamide materials, HTPA is no exception, especially in terms of its excellent oil and grease resistance at high temperatures.

5. Moisture absorption. HTPA fiber reinforced products have low moisture absorption, with a water absorption rate only half that of equivalent glass fiber reinforced PA46 products. This low moisture absorption can save customers more drying costs, and the dimensional stability of the product is better.

6. Resilience. The excellent impact toughness of HTPA makes it a material choice for high demand manufacturing.

Types and properties of traditional high-temperature nylon

PA46

PA46 is an aliphatic polyamide formed by the condensation of butylamine and adipic acid. Compared to PA6 and PA66, PA46 has more amides on each given length chain and a more symmetrical chain structure, which allows its crystallinity to reach up to 70% and gives it a very fast crystallization rate.

The melting point of PA46 is 295 ℃, and the HDT (hot deformation temperature) of unreinforced PA46 is 160 ℃. After being reinforced with glass fiber, its HDT can reach up to 290 ℃, and its long-term use temperature is also 163 ℃.

The unique structure of PA46 endows it with unique properties that other materials cannot achieve. As the full owner of PA46 property rights, DSM Company is gradually industrializing its excellent performance through continuous modification. While ensuring its high-temperature resistance, various special applications such as ultra-wear resistance, ultra-high rigidity, and ultra-high fluidity have been continuously developed.

In terms of high temperature resistance, DSM in Chinapla in 2008

PA46

PA46 is an aliphatic polyamide formed by the condensation of butylamine and adipic acid. Compared to PA6 and PA66, PA46 has more amides on each given length chain and a more symmetrical chain structure, which allows its crystallinity to reach up to 70% and gives it a very fast crystallization rate.

The melting point of PA46 is 295 ℃, and the HDT (hot deformation temperature) of unreinforced PA46 is 160 ℃. After being reinforced with glass fiber, its HDT can reach up to 290 ℃, and its long-term use temperature is also 163 ℃.

The unique structure of PA46 endows it with unique properties that other materials cannot achieve. As the full owner of PA46 property rights, DSM Company is gradually industrializing its excellent performance through continuous modification. While ensuring its high-temperature resistance, various special applications such as ultra-wear resistance, ultra-high rigidity, and ultra-high fluidity have been continuously developed.

In terms of high temperature resistance, DSM launched its new high-performance STAN YL Diablo on Chinaplas in 2008. It has long-term heat resistance stability and can operate normally for over 3000 hours at high temperatures of 230 ℃, while the mechanical performance decreases by less than 15%.

PA6T

PA6T is a typical representative of semi aromatic nylon, which is formed by condensation of hexanediamine and terephthalic acid. Pure PA6T has a melting point of up to 370 ℃, at which nylon has degraded and cannot be thermoplastic formed. Therefore, the PA6T in circulation on the market is a copolymer or composite that has reduced its melting point after copolymerization with other monomers.

PA6T introduces a large number of benzene rings on the basis of fatty chains. Compared with traditional PA6 and PA66, PA6T has higher Tg, low water absorption, dimensional stability, and high heat resistance. Due to the need to introduce other monomers for copolymerization to reduce the melting processing temperature of PA6T, different monomer ratios become the key to PA6T modification. Therefore, it can be said that there is great potential for the development of high-temperature resistance modification of PA6T.

Shanghai Jieshijie Company has also successfully launched the PA6T series of high-temperature resistant nylon and has put it into production.

PA9T

PA46 is an aliphatic polyamide formed by the condensation of butylamine and adipic acid. Compared to PA6 and PA66, PA46 has more amides on each given length chain and a more symmetrical chain structure, which allows its crystallinity to reach up to 70% and gives it a very fast crystallization rate.

The melting point of PA46 is 295 ℃, and the HDT (hot deformation temperature) of unreinforced PA46 is 160 ℃. After being reinforced with glass fiber, its HDT can reach up to 290 ℃, and its long-term use temperature is also 163 ℃.

The unique structure of PA46 endows it with unique properties that other materials cannot achieve. As the full owner of PA46 property rights, DSM Company is gradually industrializing its excellent performance through continuous modification. While ensuring its high-temperature resistance, various special applications such as ultra-wear resistance, ultra-high rigidity, and ultra-high fluidity have been continuously developed.

In terms of high temperature resistance, DSM launched its new high-performance STAN YL Diablo on Chinaplas in 2008. It has long-term heat resistance stability and can operate normally for over 3000 hours at high temperatures of 230 ℃, while the mechanical performance decreases by less than 15%.

PA6T

PA6T is a typical representative of semi aromatic nylon, which is formed by condensation of hexanediamine and terephthalic acid. Pure PA6T has a melting point of up to 370 ℃, at which nylon has degraded and cannot be thermoplastic formed. Therefore, the PA6T in circulation on the market is a copolymer or composite that has reduced its melting point after copolymerization with other monomers.

PA6T introduces a large number of benzene rings on the basis of fatty chains. Compared with traditional PA6 and PA66, PA6T has higher Tg, low water absorption, dimensional stability, and high heat resistance. Due to the need to introduce other monomers for copolymerization to reduce the melting processing temperature of PA6T, different monomer ratios become the key to PA6T modification. Therefore, it can be said that there is great potential for the development of high-temperature resistance modification of PA6T.

Shanghai Jieshijie Company has also successfully launched the PA6T series of high-temperature resistant nylon and has put it into production.

The research results show that pure PA10T has a high melting point of 319.1 ℃, and its excellent heat resistance makes PA10T demonstrate potential commercial value.

Jinfa Technology, a leading domestic plastic modification enterprise, has commercialized this technology. Its brand name is Vicnyl's PA10T product, which has excellent heat resistance, ultra-low water absorption, better dimensional stability, lead-free soldering temperature up to 280 ℃, excellent chemical resistance, and injection molding processing performance.

Moreover, it is reported that nearly half of the raw materials of PA10T resin come from castor, which is a bio based environmentally friendly material with excellent comprehensive performance and demonstrates strong market competitiveness. The commercialization of PA10T products has filled the gap in China's independent research and development of high-temperature nylon new materials, and Jinfa Company has become the second unit in China to have high-temperature nylon industrialization technology, following Shanghai Jieshijie Company.

Other PPA materials

PPA (semi aromatic nylon) is obtained by condensation polymerization of aliphatic diamines or diacids with aromatic ring containing diacids or diamines. In addition to the aforementioned materials such as PA4T, PA6T, PA9T, and PA10T, there are also many PPA varieties such as PAMXD6 and PA12T. These nylon materials have aromatic ring structures in their chemical structure, which to varying degrees increase the thermal deformation temperature. DuPont Company synthesized PA12T using dimethyl terephthalate (DMT) and dodecylamine (DDMD), with a melting point of 296.6 ℃, which has strong application value.

The Application of High Temperature Nylon

Due to its ability to provide a thermal deformation temperature exceeding 270 ℃, HTPA is an ideal engineering plastic for heat-resistant parts in the automotive, mechanical, electronic/electrical industries. Meanwhile, HTPA is also an ideal choice for components that must maintain structural integrity under short-term high temperatures. The commonly used products are shown in the table below: