Patent ID: 11958218
Assignee: PALTECH
Field: Other special machines (Mechanical engineering)
Classification: CPC B  C  Y | IPC B

Claim 0:
1. A process for producing a polymeric article comprising:
(a) providing a female mould comprising a female mould cavity and providing heating and cooling means for heating and cooling the female mould cavity,
(b) providing first, second, and third polymeric materials each independently being thermoplastic polymers, and providing a blowing agent, wherein the blowing agent is a substance which is capable of producing a cellular structure in the second polymeric material upon heating above an activation temperature,
(c) filling the female mould cavity with the first, second, and third polymeric materials (1p-3p) and blowing agent (2 b) in the following sequence:
a first batch of the first polymeric material is laid into the female mould cavity,
a second batch comprising a mixture of the second polymeric material and 5 a blowing agent is placed over the first batch of the first polymeric material, and
a third batch of the third polymeric material is laid over the second batch, and

(d) closing the thus filled cavity with a lid (12) to form a mould (10) defining a closed cavity of constant volume in time,
(e) heating the mould to a processing temperature, which is above the melting temperature of all of the first, second, and third polymeric materials and is above the activation temperature,
(f) after a process time at the processing temperature, cooling the mould to or below a demoulding temperature, and
(g) removing the lid to open the cavity and extracting the polymeric article thus produced,, characterized in that,
(h) the second polymeric material is at least 50 wt. % of recycled polymer in the form of shredded flakes comprising first and second main surfaces separated from one another by a thickness, wherein the mean thickness of the shredded flakes is between 0.1 and 10 mm, and the mean hydraulic diameter, Dh=4 A/P, of the first and second main surfaces is comprised between 5 and 150 mm, wherein A is an area and P a perimeter of each of the first and second main surfaces of the shredded flakes.