"Extrusion blow molders and brand owners in the personal care and household products markets often find liquid masterbatches to be an attractive alternative to solid concentrates," stated Raymond Sloan, head of liquid color, Clariant Masterbatches North America, in a news release. "However, until now, use of liquid color has been limited in blow molding of polyolefin resins because many liquid based carrier systems (including mineral oil) would not incorporate well with the resins. It was pigment friendly, but not resin friendly."
The new Clariant masterbatches use a liquid vehicle system that incorporates suspension aids and binders, which have been integrated into the new LVT masterbatches to allow for higher pigment loadings and lower usage rates. Additional components enhance flow and make for dramatically faster color changes, the company stated.
Additional features, according to Clariant:
Improved weld-line strength. Previous carriers had a tendency to rapidly bloom to the surface of extrusion blow molded containers, interfering with seam re-welding. In contrast, the new Clariant liquid products appear to actually assist in the formation of a strong seam. Finished products have passed industry standard top-load and drop tests.
Enhanced processing characteristics. The new Clariant liquid colors have a positive effect on material flow in the extruder. Reduced screw slippage leads to improved mixing and more complete dispersion and less streaking. It also results in processing temperatures as much as 17°C (30°F) lower and, therefore, less cooling is required.
Faster color changes. The Clariant LVT products tend not to adhere to metal surfaces and, in fact, can act as a cleansing agent, removing deposits left behind by other colorants. Color changes that might typically take several hours with solid pellet colorants can now be completed in just minutes with the new liquid colors from Clariant. This means processors spend much less time producing scrap for regrind and more time producing actual saleable containers.
"So far," Sloan stated, "Testing has been completed in several types of monolayer containers and we are confident that similar results can be achieved in multilayer applications involving both opaque color and pearlescent effects."
"Although liquids have had only limited acceptance in these markets, we fully expect our new technology, along with Clariant's industry leading technical service and global reach, will allow us to discover new opportunities in the extrusion blow molding market," he said. "Clariant is actively seeking processor partners to help us test and prove LVT benefits in specific applications."
Clariant has offered liquid masterbatches for PET and other applications on a global scale for many years. In 2008, Clariant acquired Rite Systems Inc., a U.S. supplier of liquid masterbatches and dispensing technology headquartered in Chicago, IL. The new liquid vehicle technology for extrusion blowmolding was developed there and it has been thoroughly tested in North America. It is now being rolled out through three sites in South America and others in Europe and China.