Format Messtechnik GmbH of Karlsruhe, Germany, is always looking for gaps in the foam-testing sector, that it can design new equipment to meet.
For example it has recently launched the Resimat device specifically to evaluate the behaviour of viscoelastic foams, to meet a standard from demanding Swedish furniture group IKEA.
And the German specialist has also developed the SubCASE unit for estimating pot life and monitoring cure in the CASE (coating, adhesive, sealant and elastomer) sector.
Erland Hofmann, manager of new test technologies for PU with Format, said at K2010 that SubCASE is a device to assess foam rise for microcellular foams. To test high-density, expensive formulations such as shoe soles in standard Foamat equipment, users would need 1-litre of the chemistry in a 2.5-litre container, Hofmann said: “It is much better to test smaller amounts.”
SubCASE uses 300 ml and can test PU, polyester or epoxy types — all reactive plastics — and measures start, rise time and shrinkage. Hofmann noted its use for sealing foams, which he said are gaining market share, partly since they can be applied by robot.
The device has controlled reaction temperature, with reliable measurement of core temperature using a thermocouple and of polarisation using a CMD sensor in the base of the device. Covering the base with cling film before each test, and use of a replaceable cardboard test cylinder, minimises contamination and cuts the need for cleaning.
Format’s device used to operate at a maximum of 110°C, said Hofmann. “But we have many customers in the epoxy area and also in PU who want to test at higher temperatures of 150°C,” so Format developed a new version, SubCASE HT.
This uses a different sensor system and different insulation to measure surface temperature and core temperature, which Hofmann said is, “very important because of the exotherm.” Format has used thermocouples to assess core temperature, but these had to be cut after each test.
Now the equipment uses “a cheap laboratory glass tube, which can be positioned exactly. Users lower it to the base of the device and then raise it a known amount to measure the core temperature, “without having to clean or sacrifice expensive components,” Hofmann said.
Format developed the Resimat tester, shown above with Hofmann, to measure foam recovery for viscoelastic foams. It allows assessment to IKEA specification IOS-MAT-0076. Hofmann won a prize for his poster on this at the CPI meeting in Houston.
As Hofmann explains, for the IKEA test, the equipment compresses a 150 x 150 mm sample with depth 50 mm to 150 mm to 25 percent of its original height for 60s and then allows it to recover freely. “We measure the time for 90 percent height recovery.” Three parameters, compression amount, compression time and recovery height, can be varied to meet specific demands.
“We always develop what customers tell us they want, for example the IKEA tester,” Hofmann said, noting that business is “very good.”
