Soft compounds containing elastomeric metallocene polyolefins and styrenic block copolymers

Abstract

A soft multicomponent compound comprising a styrenic block copolymer having good elastomeric properties, a paraffinic oil, a crystalline polyolefin and a metallocene polyolefin having a density from 0.86 to 0.91, a molecular weight distribution less than 3, and good distribution of ethylene and from 12% to 30% by weight of one or more α-olefin monomers having from 4 to 12 carbon atoms. The metallocene polyolefin partly replaces the styrenic block copolymer in conventional soft compounds and provides the desired softness at significantly lower oil contents, thus avoiding surface tackiness and oil extractability.

What is claimed is: 
     
       1. A soft multicomponent composition, comprising: from 30% to 50% by weight of hydrocarbon components of a blend of elastomeric polymers;   from 10% to 25% by weight of hydrocarbon components of a crystalline polyolefin; and   from 15% to 60% by weight of hydrocarbon components of a paraffinic oil;   wherein the elastomeric polymers comprise: a styrenic block copolymer having at least two monoalkenyl arene blocks separated by a saturated conjugated diene block; and   an elastic metallocene polyolefin having a density from 0.865 to 0.887, and a molecular weight distribution less than 3, and good distribution of ethylene and from 15% to 30% by weight of one or more an α-olefin comonomers having from 4 to 12 carbon atoms; and     wherein the styrenic block copolymer is at least 25% by weight of the hydrocarbon components and the metallocene polyolefin is at least 10% by weight of the hydrocarbon components.   
     
     
       2. The composition of claim 1, wherein the block copolymer has the structure S-EB-S. 
     
     
       3. The composition of claim 1, wherein the comonomer in the metallocene polyolefin is butene. 
     
     
       4. The composition of claim 1, further comprising from 5% to 40% by weight of the polymer components of a hard inorganic filler.