Leading compounder A. Schulman, Inc. is partnering with 3M to develop insulating and low-density compounds that incorporate engineered hollow glass microspheres marketed under the 3M Glass Bubbles brand. The partnership is focusing on the DACH (Germany, Austria, Switzerland) region and elsewhere in Western Europe. A. Schulman is in the process of being acquired by resin supplier LyondellBasell, with the deal slated for completion in the second half of 2018 subject to regulatory approval.
|Glass bubbles are functional fillers that can reduce density, accelerate cycle times, and eliminate notable warping in plastic parts.|
3M Glass Bubbles are finely dispersed, free-flowing powders consisting of thin-walled (0.5–1.5 µm) spherical soda lime borosilicate glass particles with an average diameter of 16–65 µm. “First innovations which are now in production, such as scuff plates in vehicles, show great potential for further light-weight applications,” says Heinrich Lingnau, Vice President and General Manager EMEA at A. Schulman. “Due to the combination of 3M’s hollow glass beads and our innovative filler systems, a weight reduction of 15 percent can be achieved without compromising on product properties.”
The glass beads can be compounded with resins such as polypropylene (PP) and polyamide (PA). A density of 0.785 is achievable with a 20wt% glass bubble loading compared with 0.9 for straight PP.
Mechanical performance in PP compounds is generally enhanced when a maleic anhydride-grafted PP (MAH-PP) coupling agent is also employed. Tensile strength at room temperature is 28.7 MPa for the MAH-PP-modified versus 30 MPa for straight PP whereas tensile modulus actually increases from 1195 MPa to 1830 MPa.
3M research has also indicated that glass bubbles can also reduce cycle time. The temperature of an ejected PP part is reduced from 90ºC to 68ºC when the glass bubble loading is increased from 0 to 20 wt%, indicating that cooling time can potentially be reduced by 37%. Glass bubbles can also decrease the degree of shrinkage and warpage observed in parts where high aspect ratio fillers such as glass fibers are used.
In addition to automotive light weighting, A. Schulman is also focusing on developing compounds with improved insulating properties for the construction industry. By using 3M Glass Bubbles in an existing compound, thermal conductivity can be reduced by 23 percent.
Some of A. Schulman’s newly developed reduced-density compounds can be used in existing molding tools without any changes in process or tool design.