Polyphthalamides
Polyphthalamides ( PPA , partially aromatic polyamides, partially aromatic polyamides) are semi-crystalline aromatic polyamides (PA) . They are semi-aromatic polyamides in which the amide groups are bonded alternately to aliphatic groups (-R-) and to benzene dicarboxylic acid groups. They belong to the class of thermoplastics . They differ in their properties from the aliphatic polyamides and the aromatic polyamides (aramids).
structure
The monomers used for the production of polyphthalamides are α, ω- diamines of different chain lengths and the benzene dicarboxylic acids terephthalic acid or isophthalic acid . These monomers polycondense to form the polymer with elimination of water . The molecular weight of PPAs produced by direct condensation is in the range between 12,000 and 16,000 kg / kmol.
The number after the designation PA refers to the number of carbon atoms in the monomer. Some monomers are abbreviated with a letter. So stands z. B. T for terephthalic acid and I for isophthalic acid. PA 6T homopolymer based on hexamethylenediamine and terephthalic acid melts at 371 ° C. Longer diamines with 9 to 12 methylene groups or copolymers are used to lower the melting point . A multi-digit number indicates that multiple monomers are being used to manufacture. PA 6T / 6I is accordingly a copolyamide that is made from several polyamide-forming monomers, namely hexamethyldiamine, terephthalic and isophthalic acid.
Polyphthalamide 6T / 66 is a copolymer of polyphthalamide 6T and polyamide 66. PA 66 contains six methylene groups between the amines and the acid segment consists of carbonyl group - four methylene groups - carbonyl group Used as an amine instead of an aliphatic amine 2-methylpentane-1,5 -diamin is used, the PPA is marked with a D. z. B. PA6TDT is a copolymer of the first segment hexamethylenediamine – terephthalic acid and the second segment 2-methylpentanediamine – terephthalic acid. Copolymers made from polyphthalamides and PTFE are also offered as unreinforced and reinforced copolymers.
Reinforced polyphthalamides
Glass fiber reinforced polyphthalamides are characterized by high mechanical strength, hardness, rigidity, heat resistance and resistance to hot lubricants and hot water. Parts made from it are particularly dimensionally stable and have a high creep strength and high heat resistance (up to 280 ° C). PA6T / 6I based on hexamethyldiamine and terephthalic acid and isophthalic acid is offered almost exclusively reinforced with glass fiber (GF). More PPAs use as reinforcements milled glass, carbon fibers or aramid fibers.
Bio-based polyphthalamides
The companies Arkema , Evonik , EMS-GRIVORY, Ter Plastics and Unitika offer bio-based PPAs based on renewable raw materials.
properties
The data sheets of the manufacturing companies provide detailed information about the product characterization.
In them properties of the polyphthalamides with those of other plastics such. B. Polycaprolactam (PA6), polyamide 66 (PA66), polybutylene terephthalate (PBT), syndiotactic polystyrene (sPS), polyphenylene sulfide (PPS) compared.
Thermal properties
Due to its partially aromatic structure, polyphthalamide is a partially crystalline material with a high melting point and a high glass transition temperature of over 150 ° C. The glass transition temperature increases with the terephthalic acid content. Polyphthalamides have a high heat resistance of more than 280 ° C.
Mechanical properties
The highly rigid material has high tensile strength and rigidity . The modulus of elasticity (E-module) of glass fiber reinforced PPAs can be up to 20,000 MPa. The notched impact strength is higher than that of comparable plastics. The constant mechanical properties with dimensional stability , only low warpage and high creep resistance enable a wide range of applications.
The flexible, chemically and thermally resistant PPA cables or hoses made of Rilsan HT from Arkema can replace aluminum in high-temperature vacuum systems .
The company Ter Hell Plastic has developed a polyphthalamide TEREZ® PPA LW F40 ECO based on castor oil, specially designed for lightweight construction applications .
Wear resistance
Because of its low coefficient of friction and low abrasion coefficient , it can be used in self-lubricating bearings and gears. Unreinforced XecoT from Unitika has an abrasion coefficient of 10 mm³ / (km · kN). The XecoT reinforced with 30% glass fiber has a value of 30 mm³ / (km · kN).
Moisture absorption
The moisture absorption is only 0.1-0.3%. It is lower than with other polyamides. Changes in physical properties due to water absorption are rarely observed. Deformation due to water absorption is greatly reduced.
Chemical properties
Polyphthalamides have a higher chemical resistance than standard polyamides, even against aggressive chemicals. They are media-resistant to: biodiesel fuel, brake fluid , synthetic motor oil , transmission fluid , transformer oil, glycols , sulfuric acid , road salt , zinc chloride , calcium chloride .
Drinking water pipes made from Vestamid HTplus are approved for direct contact with drinking water and food. In medical technology, PPAs are used as catheters .
Due to their high corrosion resistance, PPA can also cover soldering points.
PPAs adhere directly to a wide variety of elastomers without an adhesion promoter e.g. B. Plastic-rubber composite.
PPAs are suitable for the production of resistant fibers. Filaments can be drawn from VESTAMID® HTplus F2001 from Evonik, such as B. for stressed bristles of toothbrushes. Since it can withstand high temperatures in the long term without any problems, it is suitable, for example, for hairbrushes when styling.
Electrical Properties
Polyphthalamides have good insulating properties. The products are characterized by high tracking resistance, which is only slightly affected by the moisture content of the material. The specific volume resistance and the surface resistance are very high.
Newer PPAs from RTP (RTP 4099 series) are thermally conductive and electrical insulators ( and ) or alternatively thermally conductive and electrically conductive ( and ).
Applications
Polyphthalamide-based plastics replace metals in areas where high heat resistance and high mechanical stability are required at the same time. PPA is suitable for use in classic metal applications such as gas lines, supply lines, pumps or filter systems.
In automotive production , PPAs are used in fuel and cooling lines, fuel metering systems, valves, water coolers, line connectors, cooling pump impellers, pump sealing rings, air coolers, protective tubes for electrical cables and bases for LED headlights .
Because of their good sliding properties, polyphthalamides are used as processing aids in the processing of polyolefin resins. B. by coating the inside of nozzles and extruders to reduce adhesion and to reduce cleaning times when changing colors. Because of their low moisture absorption, polyphthalamides are used in sanitary facilities, e.g. B. as a housing for thermostats, valve bodies in shower fittings.
Because of their low electrical conductivity, polyphthalamides are used as electrical components as housings for connectors, three-dimensional circuit carriers, in switches and as electrical insulators. It is used in the base of LED car headlights.
Since electronic components made from VESTAMID® HTplus from Evonik are classified as flame retardant class V0 with a wall thickness of 0.4 mm, they can withstand lead-free solder baths at very high temperatures without any problems. Due to their high melting point, they enable lead-free soldering of the connection surfaces directly on a circuit board .
Ultramid 6T / 6 from BASF, based on hexamethylenediamine, terephthalic acid, and caprolactam with a melting point of 295 ° C, is used as household electrical appliances, connectors, low-voltage switchgear and in automobile and rail vehicle construction.
The unreinforced and reinforced PPA molding compounds are heat-resistant and suitable for use in the interior of aircraft, trains or ships.
PA9T Genestar from Kuraray is made up of C9 diamine and terephthalic acid . The PA9T fiber is suitable when it comes to high temperatures and chemical resistance. The PA9T fiber is used, among other things, as short-cut fiber for special papers in rechargeable batteries.
Delivery form and processing
The granulate supplied is poured into molds by injection molding . The cured PPAs can be glued , riveted , snap-connected , screwed and welded . Your surface can be painted . They can be machined mechanically by drilling , turning , milling , planing and sawing .
Manufacturer and trade name
Polyphthalamides are offered by the manufacturers under their trade names :
- Manufacturer Akro-Plastic with the trade name Akromid T
- Manufacturer Arkema with the trade name Rilsan HT
- Manufacturer BASF with the trade name Ultramid T KR PA6T / 6, Advanced N PA9T, Advanced T1000 PA6T / 6I, Advanced T2000 PA6T / 66
- Manufacturer Daikin with the trade names DA-310St, DA-810X, DA-910
- Manufacturer DSM with the trade name ForTii
- Manufacturer DuPont with the trade names Zytel HTN 51, 52, 53, 54, 92
- Manufacturer Ems-Grivory with the trade names Grivory HT1: PA6T / 6I, HT2: PA6T / 66, HT3: PA10T / X
- Manufacturer Evonik with the trade name Vestamid HTplus
- Manufacturer Kuraray with the trade name PA9T fiber Genestar
- Manufacturer Lanxess with the trade name Durethan T40 / T40SZ
- Manufacturer Mitsui Chemicals with the trade name Arlen Modified Polyamide 6T
- Manufacturer Solvay with the trade name Amodel-PPA
- Manufacturer Ter Plastics with the trade name Terez HT
- Manufacturer Ter Hell Plastic GmbH with the trade name TEREZ ® PPA LW F40 ECO
- Manufacturer Unitika with the trade name XecoT
- Compounder RTP with the trade names of the RTP 4000 series
- Compounder Bada AG with the trade names of Badamid PPA
Recycling and recovery
PPAs, like any other thermoplastic, are theoretically completely recyclable , either by remelting or as a shortened polymer after depolymerization or by recovering heat during combustion.
literature
- Cousin, Thibault, Jocelyne Galy, and Jerome Dupuy. Molecular Modeling of Polyphthalamides Thermal Properties: Comparison between Modeling and Experimental Results Elsevier 53.15 (2012): 3203-210. Web. 26 Nov. 2013. doi: 10.1016 / j.polymer.2012.05.051
- Desio, Glenn P. (1996), Characterization and properties of polyphthalamide / polyamide blends and polyphthalamide / polyamide / polyolefin blends . J Vinyl Addit Technol , 2: 229-234. doi: 10.1002 / from left 10131
- Domininghaus Hans (author), Elsner, Peter; Eyerer, Peter; Hirth, Thomas (editor). (2012), Kunststoffe: Properties and Applications , Berlin, Heidelberg: Springer (Verlag) ISBN 978-3-642-16173-5
- Harper, Charles A (June 10, 2002). Handbook of plastics, elastomers, and composites . pp. 51-52. ISBN 978-0-07-138476-6 .
- Hellerich Walter, Harsch Günther, Haenle Siegfried: Materials guide for plastics: Properties - tests - characteristic values . Carl Hanser Verlag, ISBN 3-446-21437-2 ( PDF )
Individual evidence
- ↑ a b c d Polyphthalamide, brief overview ( Memento of the original from April 26, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b c polyamide 6T-6I
- ↑ a b c Structures of polyphthalamides
- ↑ a b c d e f Glass fiber reinforced PPA from RTP Co.
- ↑ a b c d e Akromid T from Akro-Plastic ( Memento of the original from November 8, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ a b c d e Ultramid from BASF
- ↑ a b c d Rilsan HT from Arkema ( Memento of the original from April 26, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ a b c d e f g Vestamid HTplus from Evonik
- ↑ a b c Terez HT from Ter Plastics ( Memento of the original from April 26, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b c d e f g XecoT from Unitika based on renewable raw materials
- ↑ a b c d TEREZ® PPA LW F40 ECO from Ter Hell Plastic based on castor oil
- ↑ a b c Daikin PPA DA from Daikin
- ↑ a b ForTii from DSM
- ↑ a b Zytel HTN from DuPont
- ↑ a b Grivory HT from Ems-Grivory
- ↑ a b c d Vestamid HTplus for electronics from Evonik .
- ↑ a b c PA9T Genestar fiber from Kuraray
- ↑ a b Arlen modified polyamide 6T from Mitsui chemicals
- ↑ a b c d Amodel PPA from Solvay
- ↑ Product search. Retrieved June 25, 2019 .
- ↑ Badamid the company Bada
