Polyamides (Nylon) comprise the largest family of engineering plastics with a very wide range of applications. Polyamides are one of the major engineering and high performance plastics because of their good balance of properties. Polyamides are very resistant to wear and abrasion, have good mechanical properties even at elevated temperatures, have low permeability to gases and have good chemical resistance, good dimensional stability, good toughness, high strength, high impact resistance, good flow.
Polyamides find application in several sectors including automotive, consumer goods, electrical/electronics, industrial applications, engineering parts, housings, building &construction, packaging, sporting goods, etc. However, these ETPs have few disadvantages such as high moisture pick-up with related dimensional instability, high shrinkage in molded sections, high moisture absorption degrades electrical and mechanical properties, prone to oxidizing agents, strong acids and bases. Growing public awareness and increasing customer interest in bio-based plastics has led to development of several grades of polyamide from renewable feedstocks.
German producer BASF developed, produced and marketed a castor oil-based engineering polymer 50 years ago. In 2007, the company reintroduced this engineering polymer to its plastics portfolio, encouraged by increasing customer interest in bio-based plastics. BASF’s Ultramid Balance, a polyamide 6.10, is comprised around 60% sebacic acid, a castor derivative. It has a superior performance compared to the standard polyamides PA6 and PA66, and offers dimensional stability and better resistivity against numerous chemicals. Lupranol Balance, a polyol made up of 31% castor oil by weight, is produced by BASF’s European polyurethane (PU) subsidiary, Elastogran, mostly for the synthesis of soft PU foams used in mattresses.
Arkema has also been working with castor derivatives since the early 1940s. The France-based company first created its 100% castor oil-based Rilsan polyamide 11 (PA11) mainly to make synthetic fibers as an alternative to another oil-based polyamide: nylon. Rilsan® PA11 is used in a large number of applications thanks to its outstanding properties: excellent resistance to chemicals (particularly hydrocarbons), ease of processing, a wide range of working temperatures (-40°C / +130°C), high dimensional stability and low density. It is easy to process, using most processing technologies (extrusion, extrusion-blow molding, injection molding and rotomolding). The PA11 matrix accommodates countless additives and filling agents, such as plasticisers, stabilisers, colorants, lubricants, impact modifiers, glass fiber, carbon fiber, etc.
Currently, Rilsan PA11 finds application in high value-added applications such as fuel lines in cars, offshore pipelines, gas distribution piping systems and in traditional markets such as electronics, sports equipment, furniture and automobile components. The company’s high-performance castor-based chemicals line now includes among others its first flexible, high-temperature resin, Rilsan HT, a polymer blend of PA11 and polyphthalamide; Pebax Rnew, a thermoplastic polyamide elastomer that can contain between 20% and 90% castor derivative depending on applications; Platamid Rnew, a 100% bio-based hot melt adhesive; and the newly launched Rilsan Clear Rnew, a transparent polyamide that contains 54% castor derivatives.
US-based DuPont introduced in 2007, Zytel long-chain polyamides PA10 and PA610, both based on sebacic acid. The PA10 has 100% renewable content and PA610 has over 60%.
EcoPaXX™ from DSM Engineering Plastics is a bio-based, high performance engineering plastic. The new material, which is based on polyamide (PA) 4.10, is set to be commercialized. Polyamide 4.10 is a “long-chain polyamide”. It pairs typical long-chain polyamide properties, such as low moisture absorption, with high melting point (highest of all bio-plastics) and high crystallization rate (typical for engineering plastics such as polyamide 6.6 and Stanyl polyamide 4.6). It is a green, bio-based material: approximately 70% of the polymer consists of building blocks derived from castor oil as a renewable resource. Castor oil is a unique natural material and is obtained from the Ricinus Communis plant, which grows in tropical regions. It is grown in relatively poor soil conditions, and its production does not compete with the food-chain.
EcoPaXX™ has been shown to be 100% carbon neutral from cradle to gate, which means that the carbon dioxide which is generated during the production process of the polymer, is fully compensated by the amount of carbon dioxide absorbed in the growth phase of the castor beans. It is a high-performance polyamide with excellent mechanical properties. It combines the benefits of a high melting point of ca. 250°C, with a high rate of crystallization enabling high productivity. The material has low moisture absorption and excellent chemical and hydrolysis resistance, which makes it highly suitable for various demanding applications, for instance in the automotive and electrical markets. A good example is its very good resistance to salts, such as calcium chloride. Because of its low moisture absorption, it will also keep good strength and stiffness after conditioning.
Rhodia’s Technyl eXten, a polyamide 6.10 made partly from castor oil, which offers chemical resistance, high gas barrier properties, lower moisture absorption than polyamide 6, and good mechanical properties. Rhodia has also created a new polyamide-based matrix suitable for continuous glass or carbon fibre composite materials. Available as pre-impregnated fabrics or plates, the semi-finished product range surpasses existing thermoplastic composites in stiffness, strength, ageing and recyclability. A new bio based engineering plastic broadens the use of polyamide to technically advanced applications while reducing their ecological footprint.
Technyl eXten’s benefits include:
- Excellent mechanical and thermal performance, similar to that of PA 6 as regards its high melting point (215°C);
- Exceptional chemical resistance, comparable to that of polyamide 12;
- Very high gas barrier properties;
- Low moisture absorption, halfway between that of polyamide 6 and polyamide 12.
Technyl eXten also has a reduced carbon footprint: the production of a ton of this product requires 20% less non-renewable resources than the production of a ton of conventional polyamide with equivalent performance properties. A significant reduction in the environmental impact of the material has been measured; its production from organic raw material reduces greenhouse gas emissions by 50% compared with a product produced from non-renewable sources.
Rhodia’s Fuel’In by Technyl, is a new product family of polyamide 6 and 6.6 based solutions for blowmolding, developed specifically for fuel contact applications. The product range provides new solutions for fuel storage and transportation, offering high barrier performance and weight reduction of up to 30% without compromising on safety.
Evonik Industries has expanded its range of compounds for high-performance cables to include bio-based VESTAMID® Terra DS. This polyamide 1010 (PA 10.10) is produced entirely from monomers obtained from castor oil. Castor oil is in turn obtained from the bean of the castor oil plant, which is used neither as food nor animal feed and whose cultivation does not compete with that of food crops. Molding compounds are semicrystalline and therefore distinguished by high mechanical strength as well as resistance to chemicals and stress cracking. They also have high to very high heat deflection temperatures and a low water-absorption capacity, retaining their good mechanical properties such as elongation at break and impact strength, even in high humidity.
Areas of application for VESTAMID® Terra DS cable jacketing include special cables for the automotive industry, underground cables, in which case the bio-polyamide protects against damage caused by gnawing rodents, and polymer optical fibers. VESTAMID® Terra HS is a polyamide 610 that contains approximately 60% renewable raw materials. From a technical viewpoint, this variant occupies a position between the high-performance polyamide 612 and the standard polyamides PA 6 and PA 66.