POLYPROPYLENE RESIN COMPOSITION WITH LOW LINEAR EXPANSION AND LOW GRAVITY WHICH IS NOT SENSITIVE TO SURROUNDING TEMPERATURE CHANGE AS THE COEFFICIENT OF LINEAR EXPANSION IS LOW WHICH IS FOLLOWED BY THERMAL CHANGE

摘要

PURPOSE: A polypropylene resin composition is provided to reveal hardness while having small amount of inorganic filler contents and to secure the size stability of segments by minimizing changes in balanced properties, especially linear expansion followed by thermal change.;CONSTITUTION: A polypropylene resin composition comprises 70-98 weight % of a highly crystalline polypropylene resin with more than 96% of isotactic peptide fraction by C-NMR method; and 1-20 weight % of rubber component; and 1-10 weight% of inorganic filler. The highly crystalline polypropylene resin is the polypropylene resin of a highly crystalline block copolymer. The rubber component is 'more than one selected from an armorphous ethylene α-olefin copolymer and styrene thermoplastic elastomer'. The inorganic filler is 'more than one selected from glass fiber, talc, mica, calcium carbonate, wollastonite, barium sulfate, clay, magnesium sulfate and whisker'.;COPYRIGHT KIPO 2013