HIGH-STRENGTH HIGHLY MODULOUS POLYOLEFIN COMPOSITE IMPROVED IN STRETCHING CAPACITY IN SOLID

摘要

PURPOSE: To enhance the strength by a method wherein a coextruded cap layer of a polymer constituted of a butene-1 homopolymer and a copolymer of a homopolymer and ethylene is laminated on both surfaces of a core layer constituted of polypropylene and linear low-density polyethylene, and a composite thus obtained is drawn to a specific draw ratio. CONSTITUTION: This composite is a drawn polyolefin laminate which has a tensile strength of 0.35 GPa or above and a 1% secant modulus of 10.5 GPa or above and of which the elongation at breakage is less than 10% and a laminate which is prepared by laminating a coextruded cap layer of a polymer constituted of a butene-1 homopolymer and a copolymer of a homopolymer and ethylene on both surfaces of a core layer of a polymer constituted of polypropylene and linear low-density polyethylene and by drawing the laminated material to a draw ratio of 15:1 or above. For the material usable as the core layer, a polypropylene polymer containing the linear low-density polyethylene being a copolymer of polypropylene and ethylene having highly isotactic crystallizability and of 1-butene to 5% is used. The molecular weight of the polypropylene core polymer is in the range of 0.1-20 M.F. According to this constitution, the composite of high strength and high modulus can be obtained.