Improvements in process of and apparatus for the continuous production and treatmentof flat structures of or containing plastic materials

摘要

Flat structures in endless or continuous length, such as foils, bands and plates, made of or containing plastic material, are produced and treated by placing the material to be worked between two endless bands, e.g. of metal, and subjecting it, together with the bands, to the pressure of a gas or liquid, whereby the bands are pressed against the material. The gas or liquid may be heated or cooled, e.g. it may be heated to the softening or hardening temperature of the material under treatment. The material may be passed continuously through a treatment zone which is under a constant pressure, or a pulsating pressure may be set up in the treatment zone and the material may be passed into and through this zone intermittently with a movement corresponding to the pulsations of pressure. The bands may pass between pressure plates and may be exposed to the pressure fluid which is contained in cavities within the pressure plates, elastic members being provided to effect a seal between the travelling bands and the plates. The process is applicable to the production of foils or plates of cellulose acetate, celluloid or vulcanized fibre, and to the production of thin plastic-impregnated paper board and foils. It is also applicable to such treatments as polishing, backing, matting, smoothing, stamping and other surface treatments of articles of or containing plastic materials. One or both of the pressure plates may be fashioned as a piston which is guided in a cylindrical space in the direction of the bands and is under the pressure of a liquid or gas. The space behind the piston may be connected by pipes with the cavity in the pressure plate so that the fluid pressure is balanced. As shown in Fig. 2, cavities 4, 5 are formed in top plate 1 and bottom plate 2 which are drawn together by bolts 3, and the cavities are filled with water or other fluid under pressure. Cooling or heating fluid is conveyed through pipes 6. The cavities are connected by pipes 7 and 8 to pumps whereby they may be placed under constant or pulsating pressure. The contact surfaces 9 are provided with packings 10 of a soft elastic material between which are guided two endless metal bands 11 with the material 12 to be treated located therebetween. Packings 13 are also provided between cavities 4 and 5, one of which may be used as a heating space and the other as a cooling space. As shown in Fig. 4, the bottom part 14 is made as a cylinder in which is guided a bottom plate 15 in the form of a piston. Pipe lines 17 supply liquid under pressure to pressure spaces 16, and a pipe 19 supplies such liquid to the space 18 beneath piston 15. If desired, the space 16 may be connected by a pipe line with space 18.