Patent ID: 8349961
Filing Date: 2013-01-08
Classification: C08F

Abstract:
1. A process for the preparation of a high-impact vinylaromatic (co)polymer grafted on an elastomer, which comprises: a) dissolving a first portion (X b) adding to the solution from as a functionalization and polymerization catalytic system comprising a free radical initiator (G), with F functionality, capable of extracting a proton from the elastomer polymeric chain and a stable free radical initiator comprising the group ═N—O or the group ═N—O—R′ (I), with molar ratios (I)G·F from 1 to 3, F being equal to the number of functional groups per initiator molecule which, through decomposition, produce two free radicals, wherein R′ is an (iso)alkyl radical C (i) functionalizing the first portion (X (ii) mixing of the functionalized elastomer from (i) with to second portion (X (iii) optionally mixing the elastomeric homogeneous composition from (ii) with additional liquid phase essentially constituted by a vinylaromatic monomer and/or solvent of polymerization, (iv) polymerizing the vinylaromatic monomer, at a temperature higher or equal to 120° C., wherein the weight ratio of the vinylaromatic monomer/solvent is from 60/40 to 100/0 and the weight ratio X (v) recovering, at the end of the polymerization, a vinylaromatic (co)polymer grafted on the elastomer, wherein the vinylaromatic (co)polymer grafted on the elastomer comprises a rigid matrix formed by a vinylaromatic (co)polymer and an elastomeric phase dispersed in the matrix in the form of particles with a strictly bimodal diameter distribution, wherein the particles comprise a first class having a volume average dimension of from 0.15 to 0.50 μm and a second class having a volume average dimension of from 1 to 8 μm, with a total absence of particles having dimensions between the volume average dimension of the first and second class of particles.