Title: Apparatus for moulding heat-expandable thermo-plastics material

Abstract: Heat-expandable beads of thermo-plastic material such as polystyrene are moulded by steam heating in a metal mould and venting the interior of the mould through apertures in plugs set into ports in the wall of the mould. The plugs are made of low heat conductivity material, for example nylon, to prevent the apertures being blocked by fusion of the beads in contact with the plugs due to heat conduction from the wall of the mould. The steam may be introduced into the mould through apertures in nylon plugs set in ports in the wall of the mould, the low heat conductivity of the nylon preventing the steam raising the plugs to a temperature at which the beads would burn onto the plugs. The same plugs may be used to introduce steam into the mould and then vent the interior of the mould.

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Inventors: Cotterell, Robert Frederick Joseph

Application Number: 438030
Filing Date: 1974-01-30
Publication_date: 1976-03-02
Assignee:
Primary Class(es): 425/4R 249/141, 264/51, 264/102, 425/812, 425/817R
Other Classes:
US Patent Ref:

2354433	Jul, 1944	Carter	264/101.
2707802	May, 1955	Gard	249/141.
2765494	Oct, 1956	Weingart	425/812.
3377662	Apr, 1968	Fukushima	425/812.
3555620	Jan, 1971	Bucy	425/812.
3737266	Jun, 1973	Yamamoto	425/812.
3803277	Apr, 1974	Bassett	425/4.
3803281	Apr, 1974	Fix	264/102.

Other Refs: 431,9251,016,124

Sep, 1967	CH
Jan, 1966	UK

Primary Examiner: Annear, R. Spencer
Assistant Examiner: Rosenbaum, Mark
Attorney: