GB1214366A - Process for the manufacture of packaging fillers made of foamed synthetic plastics - Google Patents

Abstract

1,214,366. Moulding foamed materials. ASAHI KASEI KOGYO K.K. 26 July, 1968 [27 July, 1967; 31 July, 1967; 1 Aug., 1967 (3)], No. 35760/68. Heading B5A. [Also in Divisions B8 and C3] Shock resistant packaging materials of foamed synthetic resin, e.g. polystyrene, or a copolymer thereof, polyesters or polyethers, are produced by mechanically compressing a rigid form of the material, e.g. to 33 to 66% of the original volume, to expel a substantial amount of gaseous foaming agent whereby the material is rendered pliable, and simultaneously or subsequently cutting the compressed foam into smaller pieces. The compressing and cutting may be performed simultaneously between a reciprocable upper die 10<SP>1</SP> and a stationary lower die 14<SP>1</SP>, respectively provided with a series of interengaging concentric cutting edges 13<SP>1</SP> and grooves 15<SP>1</SP> which do not close into contact, whereby the packaging is produced as a series of concentric rings which, by suitable local shallowing of alternate opposed pairs of the cutting edges and grooves, Figs. 9 and 10, not shown, may alternatively be interconnected. By suitably configuring the cutting edges and grooves, the rings may be serrated or undulated in the horizontal plane. Alternatively, a series of spirals may be formed between the dies and these may be undulated in a vertical plane or serrated in the horizontal plane. The upper and lower dies may respectively be provided each with a centrally disposed cylindrical locating recess and projection, the latter serving also to locate the used end pads from textile yarn packages when these are employed as the rigid form of material. When rigid foam sheets are employed, the recess and projection are dispensed with. The process may be effected continuously between rolls 21, 23, each respectively provided with a group of concentric cutting grooves 28, 29 and 30, 31 the working surfaces whereof are separated by a gap 27; separate or interconnected rings may be produced. A sheet may be precompressed by passage through opposed rolls, comprising interengaging ribs and grooves, to form continuous strips which may be further subdivided in length. The moulding rollers may be formed with tongues and grooves of varying depth whereby a strip of sinusoidal configuration is obtained. Foamed sheets may also be compressed by passage through two sets of rolls and then cut into continuous strips by passage between a stationary bed comprising a series of parallel grooves and a series of rotary cutter blades. The continuous strips may be subdivided in length by cutting rolls provided with axially extending cutting regions. Examples of suitable blowing agents are given (see Division C3).