Method for producing carboxylated ethylene polymer blends

Procedure for the manufacture of carboxylated ethylene polymer blends, characterized by in a 1st step, in a fluid mixing reactor, adding 0.05-15 parts by weight (pbw) of an α,β-ethylenically unsaturated mono and/or dicarboxylic acid or its anhydride (carboxyl monomer), or a monomer mixture containing at least one carboxyl monomer and 0.01-10 pbw of a free radical-forming initiator with a 1 h half-time temperature (THW/1h) of 50-200° C., and graft-polymerizing at reaction temperatures of 30-120° C. for 5-120 min, to 100 pbw of solid-fluid particulate ethylene polymer with an MFR (190° C./2.16 kg load weight)≧20 g/10 min, chosen from among ethylene homopolymers and/or linear ethylene copolymers of composition≧80-98 wt.-% ethylene/2 to ≦20 wt.-% C3-12-olefin units and subsequently,

• in a 21 step, continuously feeding into a reaction extruder via gravimetric dosing devices:
• a) 100 pbw of the modified ethylene polymer obtained in the 1st, solid phase step—together with
• b) 150-4,000 pbw of an unmodified ethylene polymer or polymer blend with a MFR (190° C./2.16 kg load weight) of <20 g/10 min, chosen from among ethylene homopolymers or ethylene copolymers of composition≧85-98 wt.-% ethylene/2 to ≦15 wt.-% C3-12-olefin units, or compounds or reactor blends consisting of LLDPE and HDPE, together with
• c) 0-4,000 pbw of i) an olefinic elastomer having 10-100 wt.-% of units derived from propylene and 0-90 wt.-% of units derived from a monomer selected from the group consisting of ethylene or C4-12-olefin or diene units and mixtures thereof, or ii) an ethylene copolymer containing 10-80 wt.-% of comonomer units derived from vinyl acetate (EVA) or (meth)acrylic acid ester (E(M)AE) and mixtures thereof;
• and reacting the above components at temperatures of 160-260° C. such that at a reactor end, a graft-modified olefin polymer blend with a carboxylation degree of 0.05 to 1 wt.-% is continuously discharged.