Know Everything About High Temperature Nylon

High-temperature nylon (HTPA) is a heat-resistant polyamide that can be used for long periods of time on 150°C. It is a semi-aromatic polyamide made by polycondensation of terephthalic acid and 1,6-hexanediamine. The main categories of high temperature nylon include aliphatic PA46, semi-aromatic PA4T, PA6T, PA9T, PA10T, PA12T, MXD6 and its copolymers, and aromatic PPTA. High-temperature nylon in the thermal, electrical, physical and chemical resistance have a good performance, especially at high temperatures still have high rigidity and high strength and excellent dimensional accuracy and stability, can melt injection molding, extrusion processing, widely used in automotive, electrical and electronic, mechanical engineering and other fields.

Characteristics of high-temperature nylon

(1) High temperature resistance

The hot deflection temperature is 280℃ (1.8MPa), and the continuous use temperature is 180℃.

(2) Creep Properties

HTPA's high crystallinity allows it to maintain excellent rigidity at high temperatures (greater than 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 the molecular chain segments, which makes the molecular structure more regular and the chain segments 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 the high temperature oil and grease resistance is very good.

(5) Moisture absorption

HTPA fiber-reinforced products have low moisture absorption, which is only half that of an equivalent glass fiber-reinforced PA46 product. This low moisture absorption can save more drying costs for customers, and the product's dimensional stability is better.

(6) Toughness

HTPA's excellent impact toughness makes it the material of choice for demanding productions.

Types of high-temperature nylon

(1) PA46

PA46 is an aliphatic polyamide condensed from butanediamine and adipic acid. Compared with Pa6 and Pa66, PA46 has a higher number of amides per given length of chain and a more symmetrical chain structure, which allows its crystallinity to be as high as 70% and gives it a very fast crystallization rate.

The melting point of PA46 is 295°C. The heat distortion temperature of unreinforced PA46 is 160°C, while after glass fiber reinforcement, its heat distortion temperature can be as high as 290°C, and its long-term use temperature is also 163°C.

The unique structure of PA46 gives it unique properties that cannot be achieved by other materials. As the full owner of the property rights of PA46, DSM is gradually industrializing its excellent properties through continuous modification. In addition to its high-temperature resistance, various special applications such as super abrasion resistance, ultra-high rigidity, and ultra-high fluidity have been developed.

In terms of high temperature resistance, DSM in 2008 Chinaplas launched its new high-performance STAN YL Diablo, which has a long-term thermal stability, can be 230 ℃ high temperature normal work more than 3,000h, while the mechanical properties of less than 15% decline.

(2) PA6T

PA6T is a typical representative of semi-aromatic nylon, which is polycondensed from hexylenediamine and terephthalic acid. Pure PA6T melting point of up to 370 ℃, at this temperature nylon has been degraded, can not be thermoplastic molding, so the market circulation of PA6T are after copolymerization with other monomers to reduce the melting point of the copolymer or complex.

PA6T in the aliphatic chain based on the introduction of a large number of benzene rings, compared with the traditional PA6, PA66, PA6T has a higher Tg, low water absorption, dimensional stability and high heat resistance. Since PA6T needs to introduce other monomers for copolymerization to reduce the melt processing temperature, different monomer ratios become the key to the modification of PA6T, so it can be said that the high temperature modification of PA6T has a lot of room for development.

In China, Wang Peigang and others have studied the polymerization process of PA6T/66 copolymer with different aromatic ring content and its heat resistance. Shanghai Jieshijie company has also successfully issued the PA6T series of high-temperature resistant nylon, and has been put into production.

(3) PA9T

PA9T is developed by Japan Kuraray company alone, it is polycondensed with nonylenediamine and terephthalic acid. Although the same semi-aromatic nylon, PA9T in the processing of the same does not need to be like PA6T to lower the melting point by copolymerization modification, pure PA9T melting point of 306 ° C. PA9T high glass transition temperature (125 ° C) and high crystallinity, endowed with good toughness in high temperature environments.

At the same time it also has other PA materials incomparable chemical resistance, second only to PPS, and its water absorption is only 0.17%, the lowest of all PA. PA9T comprehensive performance is undoubtedly the traditional heat-resistant nylon in the better one, and with the continuous expansion of the scale of production, the cost of its cost will be close to the cost of ordinary PA, so PA9T is a variety of great potential for development.

(4) PA4T

As the world's leading producer of high-temperature nylon (PA46), DSM has the world's only industrialized program of butylenediamine. Butylenediamine is the key raw material for PA46 synthesis, and this technological advantage has enabled DSM to take the lead in developing PA4T as a raw material.

This first new polymer of the 21st century has excellent spatial stability, lead-free solder compatibility, a high melting point, high hardness and mechanical strength at elevated temperatures, and shows ultra-low water absorption compared to DSM's original PA46 products, even PA9T.

The comprehensive and excellent performance of PA4T will enable it to occupy an important share in the future in the field of high-temperature-resistant applications such as electronics and automobiles, etc. The invention of PA4T is also the embodiment of the market miniaturization and the centralization of electronic products, which demand higher performance materials.

(5) PA10T

China's Cao Ming, Zhang Mingqiu, etc. on the synthesis and copolymerization of PA10T modification of systematic research, the results show that pure PA10T with a high melting point of 319.1 ℃, and its excellent heat resistance so that the PA10T shows the potential commercial value. Jinfa Technology, a leading plastic modification company in China, commercialized this technology.

At the 2009 Rubber & Plastics Expo, Jinfa proudly introduced PA10T products with the grade Vicnyl, which has excellent heat resistance, ultra-low water absorption, better dimensional stability, resistance to lead-free solder up to 280°C, excellent chemical resistance and injection molding processability.

Moreover, it is said 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, showing strong market competitiveness.The commercialization of PA10T products fills the blank of China's independent research and development of new high-temperature nylon materials, and Jinfa has become the 2nd unit in China with high-temperature-resistant nylon industrialization technology following Shanghai Jieshijie Company.

(6) Other PPA materials

PPA (semi-aromatic nylon) is produced by polycondensation of aliphatic diamine or diamine with aromatic ring of diamine or diamine. In addition to the materials described above, such as PA4T, PA6T, PA9T, PA10T, etc., there are many other PPA varieties such as PAMXD6 and PA12T. These nylon materials because of the chemical structure of the aromatic ring structure, are different degrees to improve the heat distortion temperature. Among them, DuPont used dimethyl terephthalate (DMT) and dodecylamine (DDMD) to synthesize PA12T, with a melting point of 296.6°C, which has a strong application value.

Applications of High Temperature Nylon

HTPA is an ideal engineering plastic for heat-resistant parts in the automotive, mechanical, and electronic/electrical industries because it offers heat deflection temperatures in excess of 270°C. HTPA is also ideal for parts that must maintain structural integrity at short-term elevated temperatures. HTPA is also ideal for parts where structural integrity must be maintained at high temperatures for short periods of time.

① Applications in the Electrical and Electronics Industry

Under certain conditions, the trend toward miniaturization of electrical equipment or the increase in operating current causes the temperature of its internal components to rise considerably. As a result, materials are required to have high long-term operating temperatures and low creep at high temperatures. When used for motor parts, internal components of circuit breakers, and wire-wound components such as bobbins and switches, high-temperature nylon has the advantage of being economical and practical, rivaling materials such as PPS, PEI, PES, and LCP in terms of cost performance.

The continuing trend toward miniaturization of integrated circuit boards has resulted in even thinner-walled, smaller surface-mount components. These electronic components are sensitive to the high peak temperatures in modern reflow soldering processes and require materials with high heat distortion temperatures.

In particular, the development of surface mount technology (surface mount technology, referred to as SMT), connectors, switches, relays, capacitors and other various electrical components are installed at the same time, connected to the circuit board, to promote the miniaturization of electronic components, densification, the project cost than the previous product to reduce the cost of 20% to 30%.

However, the use of SMT technology, the various electrical components and line substrate to be heated at the same time in the infrared heating device, made of various components and circuit board materials reflow resistance and dimensional stability put forward higher requirements. In order to reduce environmental pollution, the use of lead-free solder is now strongly advocated, and lead-free processes are widely implemented.

The previous lead - tin solder melting point of 183 ℃, the new solder for tin - copper - silver solder, melting point of 215 ℃, the melting point of the previous material increased by 30 ℃, this time PA66, PBT and other materials can not meet the requirements of heat resistance, so the development of heat-resistant higher material has become inevitable. High-temperature nylon has a high degree of high-temperature stability, but also has outstanding toughness and excellent fluidity and high crystallinity, thus providing an economical material program and can meet the latest design requirements of all such end markets.

The high heat distortion temperature allows the plastic components to maintain dimensional stability during the soldering process. High-temperature nylon connectors maintain dimensional consistency at soldering temperatures up to 260°C, while other high-performance plastics deform.

If a motor of equal or greater power is miniaturized, depending on the design, the temperature may rise significantly. Overloading or rotor lock-up can cause a sharp rise in temperature to more than 250°C. In order to be fully effective, a certain degree of safety is required for the motor.

High-temperature nylon ensures that it can withstand the heat generated by normal motor operation and overload conditions, and is successfully used in a variety of motor components including: end laminations, brush holders, gears, and end brackets. Due to its outstanding intrinsic properties, high temperature nylon has been successfully used in the following fields and markets: connectors; circuit breakers; wirewound; SMD components; microswitches; motor components; computers and their auxiliary equipment; communications industry; electrical products and household appliances; consumer electronics.

② Applications in the Automotive Industry

In the automotive industry, heat-resistant plastics are rapidly replacing traditional engineering plastics. The driving force behind this development stems from the requirements of three major trends in the automotive industry: improved safety, comfort, and motor management; longer warranty and service life; and the solution to the problem of high temperatures in the engine area.

In particular, the solution to environmental issues such as the reduction of CO2 emissions and the improvement of fuel consumption in the automotive industry is to increase the combustion temperature of the engine so that the fuel is fully combusted, which inevitably raises the temperature in the engine compartment and raises the heat-resistance requirements of all plastic materials.

At the same time, the plasticization of metal parts such as the fuel system, exhaust system, and cooling system near the engine has been replaced by thermosetting resins for the purpose of recycling, and the requirements for the materials have become more stringent. The heat resistance, durability, and chemical resistance of conventional general-purpose engineering plastics no longer meet the requirements.

From an economic point of view, the high-temperature nylon series has proved to be an ideal metal replacement material. It has very good creep resistance, mechanical strength, rigidity and fatigue resistance at high temperatures, while also maintaining the well-known advantages of plastics, that is, easy processing, limited finishing requirements and the freedom to develop and design complex and integrated functional parts, weight reduction and noise reduction and corrosion resistance.

In conclusion, the excellent characteristics of high-temperature nylon can bring many benefits to users, and conversion to HTPA from PA6, PA66, or PET/PBT materials basically does not require modification of molds, etc., so there is a bright future in a variety of applications that require high-temperature resistance.