| 摘要 |
1317452 Extruding into moving mould means JTAGA 14 May 1970 [14 May 1969] 23427/70 Heading B5A In a process wherein molten thermoplastics; e.g. polyolefins or polyamides or foamed thermoplastics, are extruded through an orifice defined between a stationary die 1 and a moving chain of moulds 2 which define a ridged surface 2, 2<SP>1</SP>, leakage of thermoplastics rearwardly of the die is prevented by one or more die barrier members 5 which are movable to maintain contact or close proximity with the mould surface. In the Fig. 5 embodiment, the member 5 is biased into contact by a spring 6, and in the Fig. 6 embodiment (not printed) the member is pivotally mounted on the underside of the die and contact is maintained by the extrusion pressure. The contact may alternatively be effected by reciprocation of the member by a cam track, either running along the side of the moulds, or located independently of the moulds. The thermoplastics flow from the front underside of the die 1 may also be regulated by one or more freely rotatable or driven cooled pressure rollers, 12a, 12b, Fig. 9, the temperatures of which are independently adjusted by internally circulated cooled or warm water, or alternatively, or in addition, by an endless belt passing over the cooled rollers, Fig. 10. The cooled rollers or belt also act to avoid moulded article deforming stresses, by effecting cooling of the contacting thermoplastics surface under the same conditions as the opposite surface cooled by the moulds, and similarly act to effect the formation of a skin layer with expanded plastics when the rolls or belt provide a gradually widening space between the moulds in which foam expansion is effected. The roll 12a, Fig. 9, may be recessed as at j to pattern the extrusion, or may be a printing roll to effect anastatic, intaglio, or lithoprinting. A printed paper c, Fig. 10, may be laminated to the extrusion, or may alternatively be applied by an endless belt located subsequent to an initial cooling roller.
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