SU413050A1 - - Google Patents

Description

one

The invention relates to the industry of processing polymeric materials and, in particular, to the manufacture of various products from polymeric materials, for example pipes.

A known method of producing pipes from a thermoplastic oriented film wound on a mandrel.

The disadvantage of this method is low physical and mechanical properties and insufficient stability of the geometrical parameters of the products under the conditions of non-temporal temperature regimes of operation.

In order to manufacture pipes of large diameter with increased strength, the wound workpiece is heat-shrunk at a temperature higher than the orientation temperature of the film, but lower than the melting temperature of the thermoplastic.

The starting material for the production of products according to the proposed method is a thermoplastic single-binoenoientonen film with a thickness of from 10 to 100 microns. The film is wound tightly and evenly on a mandrel that matches the configuration of the desired product. The material for making the mandrels are metals and nonmetallic materials, which have a rather large linear expansion coefficient in the range of temperatures close to the temperatures of maximum shrinkage by film 2

ki The marking is carried out in several layers depending on the desired thickness of the product, after which the top layer of films is fixed by welding or by any other method. A mandrel with a multilayer laminated film onto it is then put into a heat chamber in which it is kept at such time parameters as temperature, when maximum relaxation of stress occurs (the temperature must be several degrees higher than the oriental temperature, but less than the melting temperature). In the process of thermo annealing, the heating of an oriented film causes voltage re-tapping1 | arising from its fabrication at the time of stretching, which create internal stresses, which lead to some shrinkage of films. The donor filament force is created by the mandrel expanding during heating. After thermojing, the mandrel is cooled and the finished product is removed from it. For ease of removal, the mandrel is recommended to be made with tapered or detachable. The products obtained in this way are not monolithic, on the film of films they are packed very tightly, due to which adhesion between the layers is achieved.

Example. From a biaxially oriented polypropylene film having a nrential orientation in the fractional direction, 20 microns thick (orientation krati in the film production process is 8: 1 in irodol and iraleration, and with a diameter of 6: 1) and a pipe

60 mm and 3.5 mm thick steak. Winding pleiki lead to a metal mandrel of a circular cross section with a diameter of 53 mm. The annealing temperature is 160-165 ° C. Exposure to a heating cabinet was performed for 30 minutes. Below, the properties of the pipe obtained by the described method are compared with the properties of pipes of similar geometrical sizes, commercially produced from polypropylene by the extrusion method.

Subject invention

A method of producing pipes from a thermoplastic oriented film wound onto a mandrel, characterized in that, in order to manufacture pipes of large diameter, of increased strength, the coiled workpiece is heat shrinkable at a temperature exceeding the orientation temperature of the film, but lower than the melting temperature of the thermoplastic.