US 11,286,365 B2Granted

Process for recycling polyolefins

AssigneePolymetrix AG

InventorAndreas Christel

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Abstract

A process for recycling polyolefins comprising the steps of extruding used polyolefin material, producing granules from the polyolefin material exiting from the extrusion into a liquid cooling medium, separating the cooling medium to obtain a dry polyolefin granulate, and treating the dry polyolefin granulate in a treatment space with a treatment gas, preferably by counter-current flow, immediately after separation of the cooling medium, the dry polyolefin granules still have a granule temperature (T2) which is above a temperature (T1) of the liquid cooling medium and in the range of 71° C.-200° C., preferably 80° C.-160° C., but below the melting point of the granules, and at least 75% of the dry polyolefin granules, in the treatment space, have a dry temperature (T3) which is in the range of granule temperature (T2)±20° C., but below the melting point of the granules.

Claims15

Dependent claims

A process for recycling polyolefins, the process comprising the steps of:

a) extruding a used polyolefin material,
b) producing granules from the polyolefin material emerging from the extrusion into a liquid cooling medium,
c) separating the cooling medium to obtain dry polyolefin granules, and
d) treating the dry polyolefin granules in a treatment space with a treatment gas to remove volatiles,
wherein carrying out the process in such a way that the dry polyolefin granules, directly after separation of the cooling medium in step c), still have a granule temperature (T2) which is above a temperature of the liquid cooling medium (T1) in step b) and is in the range of 71° C.-200° C., but below a melting point of the dry polyolefin granules, and at least 75% of the dry polyolefin granules, in the treatment space, have a treatment space temperature (T3) which is in the range of the granule temperature (T2) ±20° C., but below the melting point of the dry polyolefin granules.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/803,227Filed 27 Feb 2020
Priority: EP 1916307515 Mar 2019
Published: US 2020/0291200 A117 Sep 2020
Granted: 29 Mar 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

C08J 11/06
Of polymers: without chemical reactions
F26B 3/08
The gas or vapour flowing through the materials or objects to be dried: so as to loosen them, e.g. to form a fluidised bed
B29B 9/065
In the form of filamentary material, e.g. combined with extrusion: under-water, e.g. underwater pelletizers
B29B 9/16
Making granules: auxiliary treatment of granules