US 12,503,574 B2 · Pelletization of a polymer stabilizer mixture

Abstract

The invention relates to a method for manufacturing a pellet in a pellet mill, which method comprises the steps of (A) pressing a mixture for compaction by a roller through a nozzle to obtain a strand, and (B) comminuting the strand to obtain the pellet, wherein the mixture for compaction comprises (i) 87 to 97 wt. % of a polymer stabilizer mixture polymer stabilizer mixture, which comprises the polymer stabilizers (i-1) 21 to 29 wt. % of tris(2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4), (i-2) 21 to 29 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl]methane (CAS-No. 6683-19-8), (i-3) 8 to 12 wt. % of a C16-C18 fatty acid calcium salt, (i-4) 36 to 44 wt. % of a calcium oxide, and wt. % of the polymer stabilizers (i-1), (i-2), (i-3) and (i-4) are based on the weight of the polymer stabilizer mixture, and (ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 100 J/g at 101.32 kPa. The pellet is useful for a dust-free handling of its polymer stabilizer mixture at a manufacturing of a stabilized polymer. Furthermore, a method for stabilizing a polymer, which is a polyolefin, a polystyrene or a mixture thereof, is disclosed, which comprises the dosing of the pellet to the polymer.

Claims15

Dependent claims

A method for manufacturing a pellet in a pellet mill, which comprises a roller and a die with a nozzle, which method comprises the steps of

(A) pressing a mixture for compaction by the roller through the nozzle to obtain a strand, and
(B) comminuting the strand to obtain the pellet,
wherein the mixture for compaction comprises the components
(i) 87 to 97 wt. % of a polymer stabilizer mixture, which comprises the polymer stabilizers
(i-1) 21 to 29wt. % of tris (2,4-ditert-butylphenyl) phosphite (CAS-No. 31570-04-4),
(i-2) 21 to 29 wt. % of tetrakis-[3-(3,5-ditert-butyl-4-hydroxy-phenyl)-propionyloxymethyl] methane (CAS-No. 6683-19-8),
(i-3) 8 to 12 wt. % of a C16-C18 fatty acid calcium salt,
(i-4) 36 to 44 wt. % of a calcium oxide, and wt. % of the polymer stabilizers (i-1), (i-2), (i-3) and (i-4) are based on the weight of the polymer stabilizer mixture, and
(ii) 3 to 13 wt. % of a processing aid, which is a propylene-ethylene copolymer and which possesses a melting enthalpy below 100 J/g at 101.32 kPa, wherein the melting enthalpy is determined by a differential scanning calorimetry according to EN ISO 11357-3,
and wt. % of the components (i) and (ii) are based on the weight of the mixture for compaction.

7 more elements

Dependencies are inferred from the claim text.

Pelletization of a polymer stabilizer mixture

Life of this patent

Pelletization of a polymer stabilizer mixture

Life of this patent

Abstract

Claims15