NL8005039A - METHOD AND APPARATUS FOR MANUFACTURING FORMS FROM THERMOPLASTIC PLASTICS, WHICH, BY PHYSICAL INFLUENCES, IN PARTICULAR, TEMPERATURE INFLUENCED IN ITS PARTIAL CRYSTALLINE STATE. - Google Patents

Description

4 N / 29892-tM / lb

Method and device for producing green bricks from thermoplastic plastic, which can optionally be set in its partly crystalline state by physical influences, in particular temperature influences.

The invention relates to a method and device for manufacturing green bricks from thermoplastic plastic, which can be adjusted to its partly crystalline state by physical influences, in particular temperature influences, by:

Forming a semi-finished product, in particular continuous extrusion of a tape or hose, from the plasticized plastic, stabilizing the semi-finished product by cooling at least on a surface, warm-conditioning the stabilized semi-finished product to hot formability and hot-forming before obtaining form-retaining final moldings from the semi-finished product.

German Offenlegungsschrift 2830740 and 2830788 disclose methods for manufacturing thin-walled articles from crystalline thermoplastic material. The thermoplastic material to be processed in these processes, in particular polyolefin, is in any case only 20 of a crystalline nature and thus only offers the possibility of adjusting the partially crystalline state in the molding wall to a greater or lesser degree of crystalline and through temperature control and utilization. of physical influences to influence the crystals present in the plastic of the blank wall. Accordingly, these known methods are also arranged to control the crystallinity of the plastic and the physical influence of the crystals in the plastic in the production process of the green bricks in such a way that an optimal approach to the desired properties of the green wall and at the same time usable conditions for hot-forming are available.

British Patent Specification 1514277 also already discloses the production of blisters, in particular bottles, from polyester material by combined injection molding and blow molding. In this case, a preform must first be produced by 8005039 - 2 - injection molding and stabilized on the outer surface by cooling. Then a first broadening under stretching of the cooled wall zones and then complete blow molding must take place. This known method is relatively complicated, takes considerable time and cannot be carried out as a continuous process with the formation of a semi-finished product.

The object of the invention is to provide a method and apparatus which make it possible, when processing plastics which can be set amorphously or partly crystalline, as desired, in the molding wall in the molded wall, by physical influences, in particular temperature influences. to set the desired crystallinity state and degree of crystallinity, thereby achieving desired physical properties, for example, desired elasticity, strength and, for example, temperature resistance of the green brick.

According to the invention, this object is achieved by the use of the following method features: For the manufacture of plastic bricks, the crystallinity state of which is optionally adjustable between amorphous and partly crystalline, the desired crystallinity state in the molding wall is adjusted by a first heat conditioning to be carried out on the semi-finished product and a second heat conditioning to be carried out on the green brick; the physical influences to be exerted on the semi-finished product between the stabilizing and hot-forming to be effected are determined in a predetermined manner in order to achieve a desired preparative crystallinity condition and hot-deformability of the plastic of the semi-finished product. tuned and modified, wherein a temperature profile is prepared over the semi-finished cross-section, adjusted to the subsequent hot deformation and the desired final crystallinity state in the plastic of the blank wall preparatory; and the second hot conditioning during the hot deformation and optionally is followed thereafter with temperature control to obtain or maintain the desired final crystallinity state in the plastic of the molding wall, respectively, with obtaining the dimensional stability. of the green brick.

On the one hand, the method according to the invention offers a large number of optionally changeable and adjustable method parameters, which reproducibly and accurately predeterminably influence the final crystallinity state of the plastic in the molding wall and the physical properties important for the use of the molding.

The effective application and mutual combination of the utilized process parameters, in particular of the heat treatment during the process, becomes particularly favorable through the use of two warm conditioning runs. Furthermore, the method according to the invention also offers the possibility of applying additional physical treatment steps, such as stretching, rolling, calander, compaction, irradiation, electrostatic treatment, electromagnetic treatment and the like without the stability of the manufacture and the desired stable setting of adversely affect the crystallinity state in the plastic of the molding wall. Also for these additional physical treatment steps, the two warm conditioning courses offer favorable application and combination options.

A method of principle given within the scope of the invention is characterized in that the semi-finished product is cooled to a temperature during the stabilization and initial heat-conditioning over its entire cross-section while the desired final crystallinity state is adjusted, without any significant change in the crystallinity state. in the plastic, and when setting the temperature profile for the requirements for hot-forming in all semi-finished zones, temperatures are maintained at which no significant change in the crystalline state occurs, and during the hot-forming deep drawing and second heat-forming for fixing the crystallinity state in the plastic and the thereby formed and reinforced molding wall.

40 With this method, which is possible in principle according to the invention, the final crystallinity state desired in the plastic of the green brick wall is largely set at an early stage, namely during the stabilization and initial warm-conditioning of the semi-finished product and until preparation of the green bricks held very extensively.

This principle method can be utilized to set a largely amorphous state in the plastic in the semi-finished product during the stabilization and subsequent first heat-conditioning, and this largely amorphous state in the second heat-conditioning, including the heat-forming, to such an extent possible to keep.

The moldings manufactured in this way have an amorphous state in the plastic material of their wall and are distinguished by relatively high elasticity and compliance.

However, they have only a relatively low temperature shape resistance for this.

Another basic method embodiment according to the invention consists in that the semi-finished product is rapidly cooled over its entire cross-section during stabilization and initial heat-conditioning and is adjusted to a temperature profile which permits heat-deformation, but temperatures in all semi-finished product zones persists, with no substantial change in the crystallinity state in the relevant plastic; the heat-forming takes place on at least one molding surface, which is heated to a temperature, crystal growth in the relevant plastic occurs, and the second heat-conditioning in temperature and duration on setting occurring in contact with the molding wall with the heated molding surface. of a desired partial crystallinity of the plastic of the blank wall.

In this process embodiment, a crystallinity state in the plastics of the semi-finished product is pre-set and starting from this crystallinity state in the hot-forming process, the desired final crystallinity state in the molding wall is obtained.

40 The synthetic material of the semi-finished product can be kept essentially in the amorphous state during the first hot conditioning 8005039 I-5.

However, it is also possible to subject the plastics of the semi-finished product to an initial low crystal growth during the first heat-conditioning. The choice of one or the other option depends, among other things, on the desired final crystallinity state in the plastic of the molding wall and the degree of crystal growth desired during the hot-forming.

In order to obtain the desired growth of the crystal growth during the hot-forming, the molding surface can be kept at a temperature in the range below to above the temperature for optimum crystal growth in the respective plastic. In order to achieve the highest possible degree of crystal growth during the hot-forming with an appropriately short hot-forming time, the mold surface will be kept at a temperature in the range of the temperature for optimum crystal growth in the relevant plastic, possibly in the upper part. of this temperature range in order to set the temperature suitable for optimum crystal growth in the plastic as quickly as possible.

When, in the process according to the invention, temperature conditions are set during the stabilization and first warm-conditioning of the semi-finished product, in which practically no or only very small changes of the crystallinity state occur, the semi-finished product can be used during the first warm-conditioning and, respectively, or between the first heat-conditioning and the heat-deformation practically subject to stretching the crystallinity state of its plastic, for example subjecting biaxial stretching as additional physical processing. This stretching can take place in a practically amorphous state of the plastic or also in a more or less partly crystalline state of the plastic. In the context of the method according to the invention, this stretching has the surprising effect that the green bricks produced under this additional physical influence have a high strength, a high elasticity and a high temperature-forming resistance combined with one another.

A. a further possibility for carrying out the method according to the invention consists in that η η n <5 Λ x fl - 6 - the semi-finished product is stabilized at its surface zones during stabilization and initial heat-conditioning at temperatures for a reinforcement which is suitable for handling the semi-finished product, and internally at temperatures for optimum crystal growth in the respective plastic, and heat-forming takes place on at least one molding surface heated at a temperature at which crystal growth occurs in the respective plastic.

This embodiment variant of the method according to the invention is particularly suitable for cases in which as far as possible crystallization of the plastic in the molding wall is desired. Green bricks manufactured according to this embodiment of the method are distinguished by a particularly high temperature-resistant shape. In these embodiments of the method according to the invention it is expedient for the plastic in the interior of the semi-finished product to be adjusted by the influence of the set temperature and the duration of the first heat-conditioning to form a crystallinity state, wherein the plastic in question is still heat-deformable, however, if desired, the plastic can also be transferred in the interior of the semi-finished product by the influence of the set temperature and the duration of the first hot conditioning in a criticality condition which the other side of the limit of the actual hot formability of the plastic in question. In this case, the surface zones of the semi-finished product, which are kept more or less in an amorphous or only slightly partly crystalline state, form sufficiently durable trays during the heat-forming, between which the plastic already crystallized outside the actual hot-deformability in the interior of the semi-finished product can still be deformed. In this last embodiment of the method according to the invention it is particularly advantageous to heat the mold surfaces at a temperature for optimum crystal growth in the relevant plastic. As a result, a final heating of the total plastic of the shaped molding wall takes place and there through 40 by an even crystallization.

8005039 - 7 -

A further possibility for carrying out the method according to the invention is characterized in that the semi-finished product, during the stabilization and initial heat-conditioning, is set at temperatures for a reinforcement which is suitable for handling the semi-finished product and essentially in the interior. the aplasticizing temperature used in the extrusion of the web is left; heat-molding takes place on at least one molding surface 10, which is heated to a temperature at which crystal growth occurs in the relevant plastic material and the molding wall is kept for a second period of time attuned to the desired final crystallinity state of the molding wall for the second heat-conditioning. 15 a temperature at which crystal growth takes place in the plastic of the molding wall.

In this method embodiment which is possible according to the invention, the plastic is kept in the interior of the semi-finished product at a temperature which is above the temperature range in which crystal growth occurs in the relevant plastic. The surface zones of the semi-finished product, on the other hand, are cooled to such an extent that the respective crystalline state, for example amorphous state or to a small extent partly crystalline state, is frozen therein. Contrary to the usual inline hot-forming process, in the actual hot deformation now a complete heating of the entire shaped molding wall is carried out and with this heating during the hot-forming and second hot-conditioning the setting of the desired or more strong in each case takes place. partially crystalline state. In this embodiment of the method, the plastic in the interior of the semi-finished product entails considerable amounts of heat in the first heat-conditioning and in the heat-deformation and second heat-conditioning, the temperature at the mold surfaces will advantageously be slightly below set temperature for optimum crystal growth to thereby achieve faster cooling of the plastic in the interior of the molded molded wall in the temperature range in which optimum crystal growth occurs.

8005039 - 8 -

In all process variants according to the invention, in which crystal growth is permitted during the actual hot-forming, the molding wall can be kept in contact with the molding surface until the plastic has reached the desired degree of crystallinity. However, it is also possible to initiate the crystal growth on the molding surface and to remove the molding from the molding surface upon achieving sufficient dimensional stability and to perform the second heat conditioning in a heat treatment device connecting to the outlet of the hot molding device 10. This second warm conditioning - starting on the mold surface - can be carried out with a constant temperature. However, it is also possible to change the temperature during the second warm conditioning, for example with temperature decreasing with time. With the latter type of temperature control, a temperature on the molding surface can be used that is suitable for optimum crystal growth in the respective plastic and the molding wall cools with time.

In the method according to the invention, heat-forming can be carried out under application of molding pressure on the plastic of the molding wall. This molding pressure may optionally be chosen for a specific compaction of the plastic.

The method according to the invention also allows the semi-finished product to be subjected to a calibrating and / or rolling operation with reduction of the thickness between additional extrusion and hot-forming for additional physical influence on the crystalline state. This calendaring or rolling can be part of the stabilization of the semi-finished product.

The method according to the invention can preferably be used for the production of green bricks from polyethylene terephthalate. However, the manufacture of green bricks from modified polyethylene terephthalate, for example 1,4-cyclohexyl-dimethylenterephthalate / isophthalate-copolymerisate, is also suitable. The production of green bricks from polybutylene terephthalate by the method according to the invention is also conceivable. In the latter case, care should be taken that the temperature range, within which the crystal growth in 8005039-9 - the polybutylene terephthalate occurs, is far down, i.e., to about 30 ° C.

In particular, a device with an extruder for the continuous manufacture of the semi-finished product, a stabilizing device for the semi-finished product and a heat-forming device and a heat-conditioning device for the semi-finished product and optionally suitable for carrying out the method according to the invention is suitable. a device for separating the green bricks from the surrounding parts of the semi-finished product. According to the invention, such a device is characterized by the following features:

A first hot conditioning station is disposed between the stabilizing device and the hot forming device;

The hot deformation device is located in a second hot conditioning station;

The stabilizing device and the hot-forming device are equipped with a control device for a predetermined optionally programmable control of the physical, in particular thermal, effects on the plastic of the semi-finished product and on the stations for the hot-conditioning, occurring in the stabilizing device and hot-forming device Devices for physical, in particular thermal action on the plastics material of the semi-finished product, molding and control devices for the specific optionally programmable control of the processing device have been added.

Such a device offers the advantage that it allows practically all variants of the method according to the invention to be carried out without important conversion measures. The device also offers the advantage that devices for desired special physical effects such as stretching, rolling, irradiation, etc. can be inserted into the device at the desired location without difficulty.

The device according to the invention can be equipped in the hot-conditioning stations mainly in the first semi-finished station with heating 40 and cooling units for the semi-finished product, respectively 0 0 0 39 -10- green bricks with control option for temperature and heating or cooling time to be. With this equipment, the heat-conditioning in the device according to the invention can be carried out in all conceivable method variants with full certainty and optimum effectiveness.

The first station for hot conditioning, namely that for the semi-finished product, may also have a stretching device for the semi-finished product with control options for stretching temperature, degree of stretching and, if necessary, stretching speed. Adding the stretching device to the first hot conditioning station has its particular advantage in that the stretching operation is carried out at a stage of the semi-finished product, with optimum conditions for the stretching itself and also for the action of the stretching on the the crystallinity of the plastic can be adjusted and can also be retained until hot-forming.

If additional devices are to be provided in the device according to the invention for calander and / or rolling a strip-shaped semi-finished product with a thickness reduction, this can be added to the stabilizing device.

In the device according to the invention, the cooling devices arranged in the stabilizing device can be provided with devices for generating a controllable temperature control acting in chronological order on the plastic of the semi-finished product. This means that when several cooling devices are placed one behind the other, they can be operated at different temperatures.

In the device according to the invention, the hot-forming device must be advantageously designed with at least one molding tool having an adjustable heatable and coolable molding surface. Advantageously, the hot deformation device may include at least one molding tool, which includes a control device for generating a predetermined optionally programmable temperature change or temperature control during the hot deformation on at least one molding surface. The hot deformation device 8005039-11 may also include at least one molding tool provided with devices for generating a predetermined controllable molding pressure. These devices for generating the molding pressure can be provided with control devices for variably and programmably varying the molding pressure during the hot deformation.

In the device according to the invention, preferably the second hot conditioning station 10 in its entrance zone may contain the hot deformation device and extend beyond the exit of the hot deformation device. In addition, the second hot conditioning station may comprise a heat treatment device for the green bricks connecting to the exits of the hot forming apparatus.

Examples of embodiments of the invention are explained in more detail below with reference to the drawing.

Show in this:

Fig. 1 is a diagram for the basic course of the method according to the invention or the basic construction of a device according to the invention? Fig. 2 shows the dependence of the crystal growth rate V on the temperature T with polyethylene terephthalate; Fig. 3 shows a group of temperature profiles for a first embodiment of the method according to the invention with polyethylene ether phthalate? Fig. 4 shows a group of temperature profiles for a second embodiment of the method according to the invention with polyethylene terephthalate; Fig. 5 shows a group of temperature profiles for a third embodiment of the method according to the invention with polyethylene terephthalate; Fig. 6 shows a group of temperature profiles for a fourth embodiment of the method according to the invention with polyethylene terephthalate; Fig. 7 shows a group of temperature profiles for a fifth embodiment of the method according to the invention with polyethylene terephthalate; Fig. 8 shows a group of temperature profiles for a sixth embodiment of the method according to the invention, with a polyethylene terephthalate 3 9-12, and Fig. 9 shows a group of temperature profiles for a seventh embodiment of the method according to the invention. with polyethylene terephthalate.

FIG. 1 shows the sequence of passes in a preferred embodiment of the method of manufacturing thin-walled articles of thermoplastic plastic, which may optionally be amorphous or more or less partially crystalline. In the completed example, an extruder press 11 is arranged, which is suitable for receiving the granulated thermoplastic plastic, for example polyethylene terephthalate, and continuously compressing and heating it, until it is melted and with a temperature TE (fig. 3 to 8) above the crystal melting point 15 to be fed to the extrusion tool, for example a wide-slit nozzle 12. In the present example, this wide-slit nozzle 12 provides a strip-shaped semi-finished product 10, which is fed from the wide-slit nozzle 12 into the stabilizing device 13. First, in the stabilizing device 13, the semi-finished product 10 is made manageable by cooling at least one surface for the further process. The tape-shaped semi-finished product 10 runs out of the stabilizing device 13 into a first conditioning station 14. This semi-finished conditioning station 25 14 has the primary purpose of setting temperature profiles in semi-finished product 10. However, it is also an object of the semi-finished conditioning station 14 to exert additional desired physical influences on the semi-finished product 10 or to fix additional physical influences previously exerted in the semi-finished product 10.

For these purposes, the semi-finished conditioning station 14 is provided with heating devices and cooling devices, which have control devices that are controllable and optionally programmable as desired. In addition, semi-finished conditioning station 14 may have devices for physically influencing semi-finished 10. This includes stretching devices, irradiating devices, optionally rolling and compacting devices. However, the latter devices can also already be installed in the stabilizing device 13.

In the illustrated example, the semi-finished conditioning station 14 is constructed in two steps, namely with a first stage 14a, which is thus designed for the heat-conditioning of the continuous semi-finished product 10, and with a second stage 14b, which is designed for the treatment and warming conditioning of the step-by-step semi-finished product 10 has been carried out. Located between the two stages 14a and 14b of the semi-finished conditioning station 14-10 in the semi-finished conditioning station 14 is a device 15 for controlling and converting the movement of the semi-finished 10 of continuous or stepwise feeding. With this device 15, the feed movement of the semi-finished product 10 is tuned to the working cycle of the step 17 receiving the semi-finished product 10 for conditioning the finished parts with the device 16 for hot-forming.

This station 17 for the conditioning of finished parts and the second station for heat conditioning 20, in its first part, contains the device 16 for hot deformation, which in the example shown is provided with deep drawing tools, the molding surfaces of which are optionally heatable or coolable and for changing the temperature during each operating cycle. According to FIG. 1, a part of the finished station conditioning station 17 is connected to the hot-forming device 16, in which, in the example shown, the strip-like semi-finished product with molded green bricks 16 from the hot-forming device passes through it. Heating and cooling devices are provided in this second part of the station 17 for conditioning the finished parts. In addition, devices for the physical treatment of the green bricks 18, for example irradiation or treatment with sound or the like, may also be arranged there.

From the second station for hot conditioning, the strip-shaped semi-finished product with molded-in green bricks 18 enters a blanking device 19, the green bricks 18 are cut out and the semi-finished product residues 20 for material-40 recovery or direct return of the crushed material. 8005039 «- 14 - material is discharged to the extruder 11.

The semi-finished product 10, referred to above as a plastic strip, for example, may have a thickness of about 2 ram in the processing of polyethylene terephthalate.

Instead of band-shaped semi-finished products, all other conceivable and continuously manufactured semi-finished products are also eligible, for example hoses, profile strands or the like.

The semi-finished product may also be a layered material of 10 different plastics, of which in any case an important part must be plastics, which are optionally amorphous or, if desired, partly crystalline, by physical influence, in particular by temperature treatment.

A pressure treatment of the plastic can be carried out on the semi-finished product, for example by rolling or calendaring in the stabilizing station 13 or also in the first part 14a of the semi-finished conditioning station 14. It is also conceivable to perform a pressure treatment of the plastic by step-by-step flat-pressing during step-through-feeding by carrying out the second part 14b of the semi-finished conditioning station 14. The invention furthermore allows a pressure treatment on the molding or the finished part, therefore, within the second station 17 for hot conditioning. Preferably, this pressure treatment will be performed on the finished part by applying a predetermined molding pressure in the hot deformation device 16. Instead of the printing treatment whether it is carried out on the semi-finished product or on the finished part, or in addition to this, an ultrasound treatment can also be carried out. The pressure treatment or the ultrasound treatment, in addition to influencing the crystallinity state, also leads to considerably higher rigidity and thus improved cold dimensional stability of the produced green bricks.

The curve drawn in Figure 2 shows the dependence of the crystal growth rate V in polyethylene terephthalate in dependence on the temperature T indicated in degrees Celsius. As shown in Figure 2, polyethylene terephthalate has between 100 ° C and the crystalline melting point (250-260 ° C). C) 8005039-15 - a crystal growth temperature range in which optimum crystal growth occurs at about 170 ° C to 175 ° C. Above the crystalline melting point, polyethylene terephthalate changes to the plasticized state. Below 60 ° C, polyethylene-5 terephthalate exists in the solid state, without any crystal growth occurring to any significant extent in the material. This means that the relevant crystallinity state of the material can be frozen by cooling the polyethylene terephthalate below 60 ° C.

In order to simplify the explanations, the amorphous state should also be regarded as a crystallinity state, namely a state with "crystallinity zero", in the context of this application.

The method according to the invention must provide economically favorable manufacturing options for plastic moldings with the above-described properties, whereby the method must offer a choice for the final crystallinity state of the plastic in the molding wall.

In principle, this is achieved with the invention in that, using the above in connection with FIG.

2, the behavior of the plastics contemplated here is produced by producing a semi-finished product by continuous extrusion at a temperature TE (compare FIGS. 3 to 8) which is above the crystalline melting point in a temperature range in which the material is in the plasticized state. From this plasticized state, the material is cooled and thermally conditioned throughout the crystal growth temperature range shown in FIG. 2 in accordance with the respective needs and requirements of the molding so that upon reaching the temperature range in which it is used as a solid is present (at polyethylene terephthalate below 60 ° C), has a desired crystallinity state associated with desired physical properties.

Some examples of possibilities that can be achieved with the heat-conditioning according to the invention are shown in the following explanation of Figures 3-8.

In the example of Fig. 3, in the manufacture of green bricks from polyethylene terephthalate, the semi-finished product 10 is strongly cooled during stabilization and, during 8005039-16, it is warm-conditioned to a temperature profile over the thickness of the semi-finished product, which is in the range of 55 to 100 ° C, in which practically no crystal growth or no crystal formation occurs. The outer zones 5 or surface zones of the semi-finished product can thereby be cooled below this temperature range, while the plastic in the interior of the semi-finished product can be warm to about 100 ° C, at least not importantly may exceed this temperature. During stabilization, as indicated in the upper part of Fig. 3, starting from a temperature profile prevailing during the extrusion and at the extrusion temperature TE, it can be cooled rapidly by the temperature shown to the left in the upper part of Fig. 3. the amorphous state in the plastic is essentially maintained or frozen. During the next warm-conditioning (middle part of Fig. 3) and the subsequent second heat-conditioning (Fig. 3 bottom part), these temperature conditions can be maintained on and in the interior of the semi-finished product 10 and the pre-coating 18, so that even then no significant crystal growth or crystal formation occurs. The green bricks produced in this way - when it consists of pigment-free plastic - are clearly transparent, which means that the plastic in the green brick wall is practically in an amorphous state. The temperature resistance of the molding is about 70 ° C.

In order to allow or mold a certain degree of partial crystallinity in the plastic of the molding wall in this method, this can be done in the stabilization and initial heat-conditioning, because the cooling of the semi-finished product 10 is carried out more slowly and in this case already a partial crystallinity to the desired degree occurs. This partial crystallinity can then be substantially maintained in the thermoforming and second hot-conditioning by corresponding temperature control. Compare the lower part of Fig. 3) in the plastic of the molding or finished part, respectively.

Fig. 4 shows a possibility for the ionization of the process according to the invention, in which the semi-finished product 10 is cooled rapidly in order to strengthen it and make it manageable at its outer zones 40 and surface zones, respectively. However, the plastic in the interior of the semi-finished product remains at a temperature which is considerably above 100 ° C. This transition from the temperature profiles located at the extruding temperature TE to the temperature profile set by stabilization is visible from the upper part of Fig. 4. When heating-conditioning to the semi-finished product after stabilization, a temperature profile can then be set, wherein the outer zones of the semi-finished product are at temperatures at up to just above 50 ° C and the core of the semi-finished product at temperatures above 100 ° C. With this temperature control during the stabilization and initial heat-conditioning, the polyethylene terephthalate in the interior of the semi-finished product 10 exhibits significant crystal formation and significant crystal growth, which is manifested by cloudiness of the material. Since the time between the conditioning of the semi-finished product (middle part of Fig. 4) and the thermoforming with conditioning of the finished part (bottom part of Fig. 4) is fixed in the method according to the invention, it can be determined by temperature profile drawn in the middle part of fig. 4 and the extent to which the temperature in the interior of the semi-finished product 10 is above 100 ° C, predetermine how large the degree of crystallization of the semi-finished product at the beginning of the conditioning of the finished part is.

In this example, hot-forming is done by drawing the workpiece onto a hot molding surface, the temperature of which must be at 120 to 180 ° C. In the completed example, a temperature on the mold surface is assumed at 180 ° C. Thus, when the finished part is started during the heat-forming process and, possibly, after the heat-forming process, the finished part crystallizes extensively, the polyethylene terephthalate crystallizes. The green brick is provided with an opaque wall (when starting from a pigment-free material). The temperature molding resistance of the green brick is above 200 ° C.

A similar process sequence would be attainable according to FIG. 5 if a temperature profile is set, as in the upper and middle parts of FIGS. 3 and 5, when stabilizing and conditioning or conditioning the semi-finished product under 8005039-18 pressure. is shown. If, in this case, in order to obtain a far-reaching crystallization in the plastic when the finished part is being conditioned, starting from the substantially amorphous state of the polyethylene terephthalate, a longer time for crystallization should be made available, or a degree of crystallinity that is not so high can be achieved as with the starting condition according to fig. 4. As indicated in the lower temperature profile of fig. 5, in such a case it is also possible to work with a slightly higher temperature on the mold surface, for instance up to 200 ° C. However, it is also possible, in particular, to continue conditioning the finished part correspondingly longer after the heat-forming process, as indicated in Fig. 1 by the second heat-conditioning station 17. The moldings produced in this way (when starting from a pigment-free material) have a transparent wall. The temperature mold resistance of the green bricks so produced is about 150 ° C to 200 ° C.

Fig. 6 gives an opportunity for carrying out the method according to the invention, which differs from fig. 3 and 5, respectively, in that during the conditioning of the semi-finished product (compare middle part of fig. 6) between stabilization and warming deforming the semi-finished product 10 is stretched. During this stretching, as the middle temperature profile in Fig. 6 indicates, additional cooling of the semi-finished product 10 occurs. The stretched, preferably biaxially stretched semi-finished product 10 is then deep-drawn on the hot molding surface during hot-forming, which may have a temperature of, for example, 150 to 200 ° C. In the example of Fig. 6, a temperature of about 200 ° C is assumed at the mold surface of the tool for hot deformation. The green bricks produced in the process embodiment of Fig. 6 again have a transparent wall (when starting from a pigment-free material) but still have a significantly improved temperature forming resistance, namely to temperatures of 200 ° C to 250 ° C. In addition, the green bricks so manufactured are distinguished by an increase in strength and elasticity.

In the example of Fig. 7, a temperature profile is set during the stabilization and subsequently during the heat-conditioning of the semi-finished product 10, wherein relatively thick surface zones 10a are cooled to a temperature below 100 ° C and kept in a practically amorphous state of the polyethylene terephthalate turn into. In the interior of the semi-finished product 10, a temperature of maximum about 150 ° C is set. Starting from this temperature profile shown in the middle part of Fig. 7, the heat-deforming and conditioning of the finished part takes place on mold surfaces which have been heated to about 150 to 180 ° C.

In the illustrated example, the temperature of the two molding surfaces between which the molding wall 18 is formed is 180 ° C. The plastic of the molding wall 18 is largely crystallized between the two molding surfaces held at 180 ° C. The green bricks thus produced have a temperature mold resistance of about 200 ° C.

In the example of Fig. 8, during stabilization, a rapid quenching of both surfaces of the semi-finished product 10 is performed. During the conditioning of the semi-finished product, a temperature is then set on the surfaces of the semi-finished product between about 50 and 100 ° C, while the polyethylene terephthalate in the core 25 or the inside of the semi-finished product still largely retains the extrusion temperature, i.e. at a temperature at about 270 ° C. The semi-finished product produced with this temperature profile (drawn in the middle part of Fig. 8) is heat-deformed between two hot forming surfaces. The molding surfaces can have a temperature of 150 to 160 ° C. As appears from the lower part of Fig. 8, an important equalization of the temperature profile occurs between the mold surfaces. As a result, the polyethylene terephthalate in the surface zones of the shaped green brick wall 18 crystallizes substantially at about 160 ° C and in the inner zone of the green brick wall 18 at about 190 ° C, i.e. in the outer zones slightly below and in the inner zones slightly above the optimum crystallization temperature of about 170 ° C. The green bricks produced in this manner have opaque green bricks (when starting from pigment-free material). The temperature shape resistance is approx. 200 ^ C.

Fig. 9 shows a modified method in which the semi-finished product is made manageable during stabilization by rapid quenching of the two surfaces.

When conditioning the semi-finished product, a temperature profile is set, which - as the middle part of the figure shows - is between the extrusion temperature (260 ° C to 290 ° C) and about 170 ° C. During the hot-forming and conditioning of the finished part, a temperature profile between 120 ° C and 170 ° C is set on the molding wall. The green bricks produced by this modified process also have opaque green bricks (when starting from a pigment-free material) and a temperature mold resistance at about 200 to 220 ° C. In addition to the above explanation, in addition to the aforementioned stretching, other mechanical and physical treatments can also be carried out in the conditioning of the semi-finished product and also in the conditioning of the finished part, for example compacting and thickness reduction by rolling or molding, irradiating with jets of all kinds, treatment with ultrasound or the like. The above-described embodiments of the method according to the invention can be used with all kinds of semi-finished products, for instance hose, profile strips or the like.

8005039

Claims (44)

1. Process for the production of moldings from thermoplastic plastic, which can optionally be adjusted to its partly crystalline state by physical influences, in particular temperature influences, by: forming a semi-finished product, in particular by extruding a strip in progress or tubing, from the plasticized plastic, stabilizing the semi-finished product by cooling at least on one surface, warm-conditioning the stabilized semi-finished product to hot formability and hot-forming to obtain form-retaining final moldings from the semi-finished product, characterized in that that for the manufacture of green bricks from this plastic, the crystallinity condition of which is selectively adjustable between amorphous and partly crystalline, the desired crystallinity condition is adjusted in the green brick wall by a first heat conditioning to be carried out on the semi-finished product and a second on the semi-finished product. green bricks 20 perform warm conditioning is processed; the physical influences to be exerted on the semi-finished product during the initial stabilization and heat-forming to be adjusted and modified in a predetermined manner in order to achieve a desired preparative crystallinity state and hot deformability of the plastic of the semi-finished product. and thereby adjusting a temperature profile preparatory to the subsequent hot deformation over the semi-finished cross-section and the desired final crystallinity state in the plastic of the blank wall preparatory; and the second hot conditioning is carried out during the hot deformation and optionally thereafter with temperature control for obtaining or retaining the desired final crystallinity state in the plastic of the molding wall in order to obtain the shape stability, respectively. 8005039 - 22 - 2. Process according to claim 1, characterized in that the semi-finished product is cooled to a temperature during stabilization and initial heat conditioning over its total cross-section while adjusting the desired final crystallinity state, with no significant change in the crystallinity state in the plastic takes place more, and also when temperatures are set to the requirements during the hot-forming requirements, temperatures are maintained in all semi-finished product zones, whereby no significant change of the crystallinity state occurs, and during the hot-forming a deep-drawing operation and second hot conditioning for fixing the crystallinity state in the plastic of the thereby formed and reinforced molding wall is effected. 3. A method according to claim 2, characterized in that the semi-finished product is rapidly cooled to a temperature at which no significant change of the crystallinity condition takes place during the stabilization and initial heat-conditioning, while maintaining the amorphous state in the plastic. 4. A method according to claim 2 or 3, characterized in that the green bricks are made of polyethylene terephthalate and the temperature in the material strip is adjusted in a range at 50 ° to 100 ° C during the stabilization and initial heat-conditioning. 5. Process according to claim 1, characterized in that the semi-finished product is rapidly cooled over its total cross-section during stabilization and initial heat-conditioning and is adjusted to a temperature profile which allows heat-deformation, but temperatures in all semi-finished zones wherein no significant change of the crystallinity state occurs in the particular plastic; the heat-forming takes place on at least one molding surface, which is heated at a temperature, at which the crystal growth occurs in the relevant plastic material and the second hot-con forming or coming into contact with the molding wall with the heating surface 8005039 - 23 - -Texturing in temperatures and time is adjusted to the setting of a desired partial crystallinity of the plastic. Method according to claim 5, characterized in that the plastic material of the semi-finished product is largely kept in an amorphous state during the stabilization and initial heat-conditioning. 7. A method according to claim 5, characterized in that the plastic material of the semi-finished product is already subjected to a first low crystal growth during the stabilization and initial heat-conditioning. 8. A method according to any one of claims 5-7, characterized in that the molding surface is maintained at a temperature in ranges below to above the temperature for optimum crystal growth in the respective plastic. 9. Method according to claim 8, characterized in that the molding surface is kept at a temperature in the region of the temperature for optimum crystal growth in the relevant plastic. 10. A method according to any one of claims 1-9, characterized in that the semi-finished product during the first heat-conditioning and between the first heat-conditioning and the heat-deformation, respectively, while substantially maintaining the crystallinity state of its plastic on a elongation, preferably biaxial elongation, is subjected as an additional physical influence. Method according to any one of claims 5-10, characterized in that during the manufacture of green bricks from polyethylene terephthalate, during the stabilization, a first warm-conditioning of the semi-finished product is set at a temperature in the range of 50 to 100 ° C and the molding surface maintains a temperature in the range of from 120 to 180 ° C. 12. A method according to claim 1, characterized in that the semi-finished product, during stabilization and initial heat-conditioning, at its surface zones at temperatures for a reinforcement suitable for handling the semi-finished product, and in the internally is set at temperatures for optimum crystal growth in the relevant plastic and heat-forming takes place on at least one molding surface 5, which is heated to a temperature at which crystal growth occurs in the relevant plastic. 13. A method according to claim 12, characterized in that the plastic in the interior of the semi-finished product is adjusted to the formation of a crystallinity state by the influence of the set temperature and the duration of the initial heat-conditioning, the plastic in question still being is hot-deformable. 14. A method according to claim 12, characterized in that the plastic in the interior of the semi-finished product, due to the influence of the set temperature and the duration of the first warm-conditioning, on the other side of the limit of the actual warm deformability of the respective plastic crystallinity state. Method according to any one of claims 12-14, characterized in that the molding surface is heated to a temperature for optimum crystal growth in the respective plastic. A method according to any one of claims 12-15, 25, characterized in that in the production of green bricks from polyethylene terephthalate during the stabilization and initial warm-conditioning of the material strip the surface zone temperature is at about 50 ° to 100 ° C and the interior zone temperature at about -30 springs can be adjusted from 140 ° to 160 ° C and the molding surface is heated to about 120 ° to 180 ° C during hot-forming and second hot-conditioning. 17. Method according to claim 1, characterized in that the semi-finished product is set at temperatures for stabilization suitable for handling the semi-finished product during the stabilization and initial heat-conditioning at the surface zones of its cross-section and in the interior substantially to the plasticizing temperature utilized in extruding 40 of the web is left 8005039-25; the heat-forming takes place on at least one molding surface which is heated to a temperature at which crystal growth occurs in the relevant plastic material and the molding wall for second heat-conditioning over a period of time attuned to the desired final crystallinity state of the molding wall at a desired temperature. temperature is maintained at which crystal growth takes place in the plastic of the molding wall. 18. A method according to claim 17, characterized in that the temperature at the molding surface is set slightly below the temperature for optimal crystal growth and the blank is kept at a temperature in the temperature range for optimal crystal growth during the second heat-conditioning. • 19. Method according to claim 17 or 18, characterized in that the plastic in the surface zones of the semi-finished product is largely kept in an amorphous state during the stabilization and initial warm-conditioning. 20. A method according to claim 17 or 18, characterized in that the plastic material is transferred to the surface zones of the semi-finished product in a predetermined low partially crystalline state during stabilization and initial heat-conditioning. 21. A method according to any one of claims 17-20, characterized in that during the production of green bricks from polyethylene terephthalate, the surface zone temperature is set at about 80 ° to 100 ° C and the temperature is stabilized and first warm-conditioned of the material strip. is left in the interior of the belt at about 250 ° to 300 ° C and the mold surface is maintained at about 140 ° to 160 ° C during hot-forming and second hot-conditioning. 22. A method according to any one of claims 5-21, characterized in that the molding wall is kept in contact with the molding surface for the second heat-conditioning. 8005039 - 26 - Method according to any one of claims 5-21, characterized in that the molding is removed from the molding surface during the second heat-conditioning and subjected to a subsequent heat treatment. A method according to claim 22 or 23, characterized in that during the second heat-conditioning the plastic of the green brick wall is largely crystallized out. 25. A method according to claims 22 to 24, characterized in that the molding wall is kept at an essentially constant temperature during the second heat-conditioning. 26. A method according to any one of claims 22-24, characterized in that the molding wall is tempered to a falling temperature during the second heat-conditioning. 27. Method according to claim 26, characterized in that the temperature control during the second heat-conditioning takes place essentially cooling down from the temperature 20 for optimum crystal growth in the respective plastic. 28. A method according to any one of claims 1-27, characterized in that the hot-molding is carried out on the plastic of the molding wall while applying molding pressure. 29. A method according to any one of claims 1-28, characterized in that the semi-finished product is subjected to a calibrating and / or rolling operation under thickness reduction for additional physical influence on the crystallinity state between the extrusion and the hot-forming. A method according to claim 29, characterized in that the calibrating or rolling operation is involved in stabilizing the semi-finished product. A method according to any one of claims 1-30, characterized in that glycol-modified polyethylene terephthalate is used as a thermoplastic production material. 32. A method according to any one of claims 1-30, 40, characterized in that polybutylene-terephthalate 80 0 5 039 - 27 - is used as a thermoplastic production material. 33. Apparatus for carrying out the method according to any one of claims 1-32, with an extruder for continuously producing the semi-finished product, a stabilizing device for the semi-finished product and a device for hot deformation and optionally a device for removing the green bricks from the surrounding area. separating parts from the semi-finished product, characterized by the features: a first heat-conditioning station (14) is arranged between the stabilizing device (13) and the hot-forming device (16); the hot deformation device (16) is located in a second heat conditioning station (17); The stabilizing device (13) and the hot deformation device (16) are with a control device for the predetermined optionally programmable control of the physical occurring in the stabilizing device (13) and the hot deformation device (16). equipped with special thermal effects on the plastic material of the semi-finished product (10); and at the heat conditioning stations (14, 17) are devices for physical, in particular thermal action on the plastics of the semi-finished product (10) and molding (18) and a control device for the predetermined optionally programmable control of added the exposure device. 34. Device according to claim 33, characterized in that the heating-conditioning stations (14, 17) have heating and cooling equipment for the semi-finished product (10) or the green bricks (18) with control options for temperature and heating or cooling time. Device according to claim 33 or 34, characterized in that the first heat-conditioning station (14) has a stretching device for the semi-finished product (10) with control option for stretching temperature, degree of stretching and possibly stretching speed. Device according to claim 35, characterized in that the stretching device is designed for biaxial stretching of strip-shaped or tubular semi-finished product (10). 37. Device according to any one of claims 33-36, characterized in that devices for calibrating and / or rolling a strip-shaped semi-finished product under thickness reduction are added to the stabilizing device (13). 38. Device according to any one of claims 33-37, characterized in that the cooling devices arranged in the stabilizing device (13) are provided with devices for obtaining an effect in chronological order on the plastic material of the semi-finished product (10). adjustable temperature control. Device according to any one of claims 33-38, 15, characterized in that the heat-forming device (16) contains at least one molding tool with an adjustable heating and cooling moldable surface. 40. Device according to any one of claims 33-39, characterized in that the hot-forming device (16) 20 comprises at least one molding tool, which with a control device for generating a predetermined, possibly programmable temperature change or temperature control during the hot forming is equipped on at least one molding surface. A device according to any one of claims 33-40, characterized in that the hot-forming device (16) comprises at least one molding tool equipped with devices for generating a predetermined, adjustable molding pressure. Device according to claim 41, characterized in that the devices for generating the molding pressure are equipped with a control device for the variable, optionally programmable variation of the molding pressure during the hot-forming process. An apparatus according to any one of claims 33-42, characterized in that the second heat conditioning station (17) in its entrance zone contains the heat-forming device (16) and is located beyond the exit of the heat-forming device ( 16) extends. Device according to claim 43, characterized in that the second heat conditioning station (17) comprises a heat treatment device for the green bricks connecting to the outlet of the heat-forming device (16). 8005039