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Advanced materials and systems to benefit rubber production
Date Published：12/10/2016 03:12:29 PM
Major developments in the rubber sector in the next few years point toward the launch of new materials and production processes.
The global demand for rubber is forecast to rise 3.9% annually, with volume demand to reach 31.7 million metric tons in 2019, according to a report by Freedonia. Asia Pacific retains its special place being the region with the largest and fastest growing market. The share of tire and non-tire applications is projected to remain steady, as will the balance between synthetic and natural rubber, according to the report.
The global market currently has a surplus of natural rubber inventory as excess supply has been the result of stocks piling high amid falling prices. It is projected that global surplus by the year 2020 will be approximately 1 million tons of natural rubber and 3 million tons of synthetic rubber.
Asia accounts for 93% of the world natural rubber production. Thailand is the largest producer followed by Indonesia and Vietnam. Other large rubber producers in the region include India, China and Malaysia. China is the world’s biggest consumer of natural rubber followed by India and the United States. Increasing consumption of tires and industrial rubber products is expected to spur demand for natural rubbers. Indonesia is the second largest rubber producer globally behind Thailand.
Thailand is the world’s largest producer and exporter of natural rubber but the industry is faced with sluggish demand and excess inventory due mainly to the lower demand from China, the world’s largest rubber consumer. Thailand accounts for about 35% of the global natural rubber supply with market value of $25 billion a year. The tire industry in Thailand remains robust and consumes more than half of the natural rubber production of the country.
Rising product portfolio
Significant developments in the rubber sector in the next few years point toward the launch of high performance rubber materials and production processes that meet the requirements of high-end customers or complex applications.
ARLANXEO, a leading player in synthetic elastomers, has launched a new nitrile butadiene rubber (NBR) grade. Krynac® XL 3375 VP is a new pre-crosslinked NBR, specifically developed to deliver high quality products with no compromise on production efficiency. It is particularly suited for extruded and calendered parts requiring good dimensional stability, such as hoses inner parts, rubber linings, semi-finished products, belts. Other key processing benefits include good calendering behavior, low shrinkage, smooth compound surface and higher compound green strength. Moreover, Krynac® XL 3375 VP delivers reduced nerviness on the mill. The pre-crosslinked structure of the new Krynac® XL 3375 VP allows exceptional performance in terms of mechanical properties such as elongation at break and tensile strength as well as extremely low compression set values.
Another company, Momentive Performance Materials, Inc. (Momentive), launched Silopren LSR 27x9 liquid silicone rubber family, a new self-bonding material capable of addressing the growing demands for hard-soft designs, and decreasing assembly steps. It also enables attaining the bonding between silicone and thermoplastics, and fulfills several complex design requirements.
The new materials from Momentive addresses the demand of industrial, automotive, medical device and consumer electronics manufacturers for improved adhesion technology between silicone elastomers and specific engineering plastics including co-polyesters, polybutylene terephthalate (PBT) and polycarbonate (PC) in order to enhance performance characteristics such as functionality, durability, protection and waterproofing. The self-bonding LSR technology developed by Momentive provides a primerless solution that helps to blend two materials through a two-shot over-molding process in order to obtain a hard-soft design and also a cost-effective manufacturing process of high part-quantities in a single integrated molding process. Surface treatment on the substrates is not needed for Silopren LSR 27x9 liquid silicone rubber, which provides short cycle times and a single step curing that will result in enhancing design freedom and productivity.
Additive manufacturing of silicone rubber
Additive manufacturing or 3D printing is expected to gain acceptance in the manufacture of silicone rubber parts. In this area, WACKER, the Munich-based chemical company, has launched a high-tech device – called ACEO® Imagine Series K – that will start the era of 3D printing rubber parts. WACKER’s printing process for the additive manufacturing of silicone rubber parts has been the subject of discussions for months as there has been no mature 3D printing technology available for silicones. The process developed by WACKER is considered a milestone in additive manufacturing.
The term “additive manufacturing,” better known as 3D printing, describes a manufacturing process in which a workpiece is built up in successive layers, without the use of a mold – i.e., it is a mold-free process. This offers designers significantly more latitude than conventional manufacturing methods. Once a product design has been generated by computer-aided design (CAD) or imaging techniques, printing can commence immediately.
According to WACKER, it’s 3D printer represents the first printer generation for industrial purposes. The ACEO® Imagine Series K prints considerably faster and is more compact in design. “The printer is based on the ACEO® technology – a drop-on-demand method developed by WACKER,” says Bernd Pachaly, head of WACKER’s silicones research and responsible for the ACEO® team. “It can be used to make parts and assemblies with complex geometries, as well as ‘impossible products,’ which could not previously be produced.”
“The automotive and aerospace industries are currently the main customer sectors for 3D,” says Mr. Pachaly, who started developing a system solution for 3D printing with silicones with his team in 2014. At the moment, additive manufacturing is growing rapidly in medical applications. Biomodeling and customized geometries are particularly promising. “In these types of applications, silicones can display their favorable properties particularly well,” emphasizes the research head. “Silicones are heat resistant, flexible at low temperatures, transparent and biocompatible. They can furthermore be pigmented in any color and have good damping properties.” With ACEO® Imagine Series K, prototypes or small series can be produced quickly and efficiently. The new 3D printing process thus offers product designers fascinating possibilities.
ACEO® technology uses a drop-on-demand method. The printer head deposits tiny silicone droplets on a substrate. In this way, the workpiece is built up layer by layer. The silicone is formulated so that the droplets flow together before the curing process begins, which is activated by UV light. The droplets and layers thus produce a homogeneous workpiece, which does not differ much from injection-molded parts. With the aid of water-soluble support materials, it is also possible to create overhang materials and internal lattices.
WACKER is already operating its own technology center – the so-called ACEO® campus – near its main site in Burghausen, Germany. The campus also features an Open Print Lab, where customers are able to test their own product ideas.