IL30321A - Process and apparatus for the continuous manufacture of shapes from thermoplastic substances,and the articles thus obtained - Google Patents

Description

PROCESS AND APPARATUS FOR THE CONTINUOUS MANUFACTURE OF SHAPES THERMOPLASTIC AND THE ARTICLES THUS OBTAINED The invention relates to a process apparatus for the continuous manufacture of solid articles from thermoplastic more particularly those a narrow melting in which process the thermoplastio material extruded into air and subsequently and shaped into form by means of a cooled and to the articles obtained If use made of a die which is so formed that force which the article carried off will act as far as the mouthpiece of the extruderf resulting article may show internal shrinkage cavities surfac Such stresses may lead to a gradual deformation of the A p ocess and suitable apparatus for carrying out process have now been found make possible to produce solid supporting are to a great extent free from the the resulting articles show great dimensional stability also at relatively high temperatures and have an attractive By solid supporting shapes are within the scope of invention to be understood articles that do not have cavities of any considerable size and that are neither reinforced nor supported by nation a continuously extending body of different tubes or coated metal proflied wire rtot within the soppe of prote tion Pf the present The nvention provides that in the process o the the extruded melt is in the air die paused accumulate to a solid having a area greater than thai of the extruded and that the mass thus aooumulated is gradually ed into the desired shape through the this propose of continuously producing articles the force serving to draw of the article no longer acts beyond the It has been found that in thus obtained there are consequently hardly any internal degree of accumulation may preferred to such an aooumulation of the plastlPieed polyme extruded into that the area of the mass aooumulated at least hut preferably at least 6 times that of the mass The degree of is very much dependent on the of the plastic substance the distance between the outf ow Pf the feeding apparatus of the plasticised substance and the and the dimensions of the articles be During operation it can readily be mined by the bulging out of the mass the quality the product obtained whether the right amount of accumulation has been obtai right accumulation it found advantage for the to pass freely through the air over a distance of not more than 5 and not less than Said distanc is largely dependent on the viscosit the general the highe the longer the distance which may be In orde to promote the gradual deformation into the desired shape the melt extruded into the air and to make that there will be no occurrence o detrimental internal stresses orming is according to the Invention preferred that during deformation the plastic subetanpe gradually This may best be achieved by having the die cooled on the side where the article leaves the This may be by directing to ths sid a stream of cooling such The thermoplastic substances which may be processed according to the invention include polyvinyl compounds such polyvinyl such as more particularly poiyamlnooaproic and more particularly polyethylene The als relates to an apparatus for carrying out the according to the This apparatus comprises an extruder with extruder and die positioned at some distance from and coaxial with said a device for drawing off the formed according to the invention provided with die having a inlet By inlet paseage to tunderetood any inlet passage which from the opening to the outlet opening has a gradually or decreasing of the inle passage depends in the first place on the shape of the article to In this connection necessar that the chang form of the accumulated mass into that of the final shape should be it is not required that the accumulated mass should get contact with the walls of the upon entry into the To the contrary it has been found that irregularities in the produot stream are removed if widest part of the inlet passage the plastic mass does not touch the As as the shape of the outlet opening of he regard to that of the extruder concerned the following should be In principle is not necessary that the shape of the extruder mouth should be adapted to that of the In general it will be possible to use an extruder mouthpiece having a round in the case of the shaped article having a very elongated A specific embodiment o the will way of with reference the accompanying which representation o an embodiment of an apparatus Out a process according to the Figure 1 shows a partly out away view of this Figure 2 shows a along the plane in Figure Figure 3 shows a alon the Figure and Figure shows the shape obtained in a along the plane in Figure 1 In 1 the re numeral refers to the mouth of an the aid of this extrude thermoplastic material is plasticised and homogenised and is subsequently forced through mouth In this ease the extruder mouth is formed of round Outle opening Opposite the extruder 1 and at some distance there positioned a die 3 has inlet passage which gradual into passage 5 having a double or On the side the die 3 awa from the extruder mouth 1 there is a nozzle 6 which connected to a feed line supply of cooling There is also a pai of feed rollers 8 which may be rotated the direction indicated by the by means of a mechanism area of or double was 77 mm the feed rate of the molten polymer was chosen that while maintaining a maximum area of the aooumulated the formed article be discharged at a rate of 1 metres per length of the in the direction of travel of the polymer was 20 and the sectional are Of the inlet opening mm ό Against water at was sprayed a a of 200 litres per insufficientOCRQuality

Claims (1)

1. A processr the continuous manufacture of solid articles as de thermoplastic in which process the material is extruded into air and is ly cooled and shaped into its final form by means of a cooled that the extruded melt is in the air space before the ale caused to accumulate to at mass having a area greate than that of the extruded in that the mass thus ated graduall drawn the desired shape through the A process as claimed in in which the of the mass accumulated is at least 6 times that of the mass A process as claimed 1 or claim 2 in the distance over which the extruded melt passes freely through the air is not more than 5 cm and not less than A process as claimed in any of claims to in which melt is gradually cooled during being drawn into the desired An apparatus for carrying out th process ing to any one of the preceding comprising an extruder and a die positioned at a distance from and substantially coaxial with said said depending upon the viscosity of the accumulated mass being generally being a greater distance for a mass of high viscosity and a lesser distance a mass of low viscosity and a device for drawing off the formed characterized in that the die is provided with a inlet Solid articles obtained according to any of the processes described in the claims 1 to process as herelnbe described reference to the An apparatus substantially before described with reference and as shown in the accompanying insufficientOCRQuality