US 10,889,034 B2
Method of forming an article
Chris Bocking, Reading (GB); and Peter Clarke, Graffham (GB)
Assigned to Bockatech, Ltd., Huntingdon (GB)
Appl. No. 16/72,545
Filed by Bockatach Ltd., Huntingdon (GB)
PCT Filed Feb. 2, 2017, PCT No. PCT/EP2017/052291
§ 371(c)(1), (2) Date Jul. 25, 2018,
PCT Pub. No. WO2017/134181, PCT Pub. Date Aug. 10, 2017.
Claims priority of application No. 1601946.5 (GB), filed on Feb. 3, 2016.
Prior Publication US 2019/0061208 A1, Feb. 28, 2019
Int. Cl. B29C 44/02 (2006.01); B65D 1/44 (2006.01); B65D 81/38 (2006.01); B60J 10/18 (2016.01); B60J 10/21 (2016.01); B60J 10/34 (2016.01); B60J 10/70 (2016.01); B60J 1/00 (2006.01); B65D 1/26 (2006.01); B29C 44/06 (2006.01); B29C 44/14 (2006.01); B29C 44/42 (2006.01); B29L 31/00 (2006.01); B29C 45/17 (2006.01); B29K 105/04 (2006.01); B29C 44/04 (2006.01); B29K 23/00 (2006.01); B29K 623/00 (2006.01)
CPC B29C 44/027 (2013.01) [B29C 44/06 (2013.01); B29C 44/141 (2013.01); B29C 44/42 (2013.01); B60J 1/00 (2013.01); B60J 10/18 (2016.02); B60J 10/21 (2016.02); B60J 10/34 (2016.02); B60J 10/70 (2016.02); B65D 1/265 (2013.01); B65D 1/44 (2013.01); B65D 81/3867 (2013.01); B65D 81/3874 (2013.01); B29C 44/0407 (2013.01); B29C 2045/1722 (2013.01); B29K 2023/12 (2013.01); B29K 2105/043 (2013.01); B29K 2623/12 (2013.01); B29K 2995/0094 (2013.01); B29L 2031/7132 (2013.01); Y02W 30/80 (2015.05)] 18 Claims
OG exemplary drawing
 
1. A method of forming an article, the method comprising:
(a) providing a mould having an outer part and an inner part, the outer part having a first cavity-forming surface and the inner part having a second cavity-forming surface;
(b) closing the mould thereby defining a cavity between the first and second cavity-forming surfaces wherein, at least one region of the cavity defining an annular cross-section of the cavity between outer and inner circumferential edges of the cavity, the first cavity-forming surface is such that a distance between the first cavity-forming surface and the second cavity-forming surface alternates between a first distance and a second distance around at least a portion of thea circumference of the at least one region, the first distance being greater than the second distance;
(c) injecting a molten plastic composition comprising a polymer and a blowing agent into the cavity;
(d) allowing the molten plastic composition to form, in the said at least one region, a first solid skin adjacent to and in contact with the first cavity-forming surface and having a first circumferential length, and a second solid skin adjacent to and in contact with the second cavity-forming surface and having a second circumferential length, wherein the molten plastic composition between the first and second solid skins remains molten, to form, respectively where the distance between the first cavity-forming surface and the second cavity-forming surface alternates between the first distance and second distance, alternating first and second thicknesses of the molten plastic composition, each first and second thickness comprising the first and second solid skins with molten plastic composition therebetween;
(e) opening the mould before the molten plastic composition between the first and second solid skins has solidified, thus allowing the molten plastic composition between the first and second solid skins, and the molten plastic composition at the alternating first and second thicknesses of the molten plastic composition, to expand by foaming, wherein said opening comprises removing the outer part of the mould so that the first solid skin is no longer in contact with the first cavity-forming surface, while maintaining the second solid skin in contact with the second cavity-forming surface.