PROPYLENE-BASED COMPOSITIONS OF ENHANCED APPEARANCE AND EXCELLENT MOLD FLOWABILITY

• Main Authors: SALEK JEFFREY S, MAJEWSKI RITA A
• Format: Patent
• Language: English
• Published: 17.04.2014
• Subjects: CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP

The present disclosure relates to a class of impact copolymer polypropylene (ICP) compositions exhibiting the advantageous combination of excellent tiger (flow) marking performance in large/long molded parts, very low gels count and exceptional mold flowability (high MFR) despite the high viscosity ratio (e.g., >4) between rubber and propylene based matrix phases. Furthermore, it has been surprisingly found that the inventive compositions are associated with a low gels count even when using a quite coarse mesh wire screen, e.g., 60 mesh wire screen, independent of screw type e.g., twin or single screw. Finally, the inventive compositions exhibit significantly reduced the levels of volatiles, and excellent stiffness-impact balance used as standalone materials or in filled compounds. The significantly reduced number of large gels leads to excellent surface appearance and paintability of the molded parts. The composition of the present disclosure is made with a bulk/gas reactor process (i.e., non-slurry/non-solvent process) that has the advantage of process simplicity, process efficiency and simplicity of compositional structure relative to the complexity in structure and process of making of compositions in the prior art.