By: David Vink
September 13, 2012
KERPEN, GERMANY (Sept. 13, 1:45 p.m. ET) — Compound and masterbatch producer A. Schulman Inc. officially opened its Schulman Academy center earlier this year at its European engineering thermoplastics business headquarters in Kerpen. The new center is a special section of Schulman’s technical center, which opened in November.
The center has been equipped with technology to function as a fluid systems development center for pipe and tube extrusion, complete with an extruder, corrugators, online dimension monitoring and pipe burst testing equipment.
The center’s main focus is presently on developing automotive fuel and coolant line tubes with Schulman materials.
Asked why the center has not focused on injection molding, innovation manager Thilo Stier indicated that three-component injection molding and blow molding might be developed at a later stage by the academy.
Stier said the key to success in tube development lies 50 percent in formulation and 50 percent in processing. “But without the equipment you can’t convince the customer. Fuel and coolant line tube products from EMS, Evonik, Arkema are all forms of the polyamide produced by those companies. We can bring different polymers together in the most economical way without being tied to a particular type of polymer,” he said.
The lower cost, easy processing alternative to today’s monolayer nylon 12 tubes consists of a Schulatube BP (break pressure) three-layer design involving a Schulamid 612 IC 4005 W outer layer, a Schulamid 612 FS 4003 central layer and Schulamid BB 4011 inner layer.
As a special co-polyamide with high monomer content, the BB (break booster) 4011 inner layer material has good elastic recovery. The more conventional unplasticized FS (fuel system) 4003 heat stabilized nylon 6/12 central layer grade is supported by the 612 IC (industrial consumer) 4005 W outer layer material, a plasticised nylon 6/12 with high ductility and viscosity. It also has around 20 percent higher heat resistance than nylon 12.
612 IC 4005 W is already used in extrusion applications because it can be extruded at high speeds without diehead build-up. The material also has high cold impact strength and high burst pressure resistance. Wittmann’s Feedmax S3-40 dosing equipment in the Schulman Academy is fitted with DIN 73378 standard blue monolayer pneumatic fluid tubes made in this material.
Schulman has already made Schulamid 612 IC 4005 W and conventional nylon 12 W monolayer tube burst pressure comparisons which show burst pressure is consistently 10 percent higher with 612 IC 4005 W. In tests, a 6mm outer diameter, 1.0mm wall thickness pipe sample had burst pressure of almost 90bar, compared with the same-sized sample in nylon 12 W with just over 80bar. Corresponding values for 15mm diameter and 1.5mm wall thickness were just over 50bar for the Schulamid material, and around 45bar for nylon 12 W.
Against a backdrop of this year’s nylon 12 shortages that have been aggravated by the CDT feedstock plant fire at Evonik’s Marl plant, Schulman stresses the “unlimited and global availability” of its three nylon 6/12 based grades for automotive fuel line pipes. These are supplied in natural and black colors.
Stier said that some three-layer tube systems were already running at customers in June. He stressed that Schulman’s tube concept allows customers to run the three grades in three-layer tubes on older and existing machinery, avoiding a need to make equipment investment.
After Bernhard Rzepka, Schulman’s CEO for the EMEA region, presented the company’s product and worldwide strategy, Stier was asked why the Schulman Academy had been built in Europe and not in a higher-growth market.
Stier replied: “We have developments in other countries, but the engineering thermoplastics competence is here in Europe. It is also easier to do development work in one place. And if we extrude a tube and find it is not very good, we can solve the problem in-house.”
Schulman technical and market development manager Peter Seb" said that conducting trials at customer facilities is difficult due to conflicts with production needs. He continued by saying there is a shift from mono nylon 12 to multilayer tubes that is being driven by the European market.
Allowance has to be made in tube materials and design for use of automatic quick connector insertion that “takes a lot of manual assembly out of manufacturing operations”, Seb" said. High temperature resistant plastics remain important, as engine downsizing means rising engine compartment temperatures, bringing nylon 12 close to its limits.
Seb" said the Schulman Academy is investigating “green” polymers by using recyclate in the central layer of multilayer tubes.
Stier pointed out that there is a need to focus on individual requirements, since “a particular region may involve more exposure to ethanol or sulphur, for example, which can be challenging. We welcome it, however, because if it gets easy, everyone can then do it”.
Maintools of Germany supplied its Extrudex EG 35-25D central, EN 40-25D inner and EN 45-30D outer layer extruders for the academy. These were fitted with Maintools dosing and extrusion controls, for production of monolayer or multilayer tubes, as well as a set of 50 pairs of 56.5mm x 68.5mm x 36mm vacuum corrugation tools with capability for eight corrugation geometries.
ETA Kunststofftechnologie of Germany provided a spiral mandrel diehead with circular melt pre_distribution that enables separate temperature control for each individual tube layer and product centering adjustment during production. Although presently provided for three-layer tube solutions, ETA says up to seven layers are theoretically possible and a further three can be added by coating processes. The company also supplies dieheads for blow molding nine layers.
Bellaform supplied the vacuum tank, cooling batch, pull-off and servo-cutter equipment. Beta LaserMike supplied Datapro 5000 online and BenchMike 283-10 laser micrometer offline equipment for measurement of outer diameter, wall thickness and concentricity. The equipment makes a total of 10 measurements; six ultrasonically and four by laser.
The final stage in Schulatube BP processing involves tube marking and coding with KBA-Metronic’s alphaJET evo pro Pig 70µm continuous ink jet printer, which can print at speeds up to 600m/min.
Having made tubes, these are then tested in static and dynamic burst pressure testing equipment developed by IPT Institut für Prüftechnik Gerätebau for testing up to 200bar pressure between - 40°C and 160°C.
Schulman also uses a Distelkamp Electronic digital microscope to prepare and display images of multi-layer pipe cross-sections on a computer screen, complete with display of individual layer thicknesses.