DE2007777A1 - Method and device for the manufacture of molded bodies from thermoset and / or thermoplastic raw materials - Google Patents

Description

Method and device for the production of moldings from duro- and / or the thermoplastic raw materials The invention relates to a method and a device for the production of molded articles from thermosetting and / or thermoplastic Pipe materials, preferably thermoplastics, such as phenolic, Urea, melamine resin molding compounds or polyethylene, polypropylene, polyvinyl chloride or the like.

For the production of moldings made of thermoset and thermoplastic Different methods are known to plastics. For example, it is thermoplastic Plastics known to produce moldings by injection molding. Likewise is it is known, molded bodies in the compression process and in particular in the cold extrusion process analogous to the processing of metals.

In the case of thermosetting plastics, it is common practice to heat them up To deform state under pressure and to harden at the same time. Most recently By now it has also become known to inject thermoset plastics to be processed in such a way that the raw material is pre-plastified by means of screws and heating or frictional heat is heated up to close to the hardening point and then injected into a heated mold and cured there completely will. This has the consequence that the curing times compared to the first mentioned Reduce methods considerably.

The purpose of the invention is, both in the processing of duro- as well as from thermoplastics to sprueless moldings, the largest possible To achieve performance by reducing the pure curing times even further will. According to the invention this is achieved with a method that is characterized in that that the raw material is brought into the plastic state as gently as possible, precisely dosed, continuously portioned, deformed and hardened or

is cooled.

In practice this can be done in such a way that the raw material is plasticized in a screw device or in a screw-piston device from a corresponding these discharged and with the help of a downstream separating device divided into portions of the desired volume and immediately while still hot introduced into an at least two-part deformation tool and in this at at a suitable temperature immediately into the intended final shape with the application of pressure is brought.

The advantage of this continuous working method is, on the one hand, that that the temperature of the melt can be controlled in such a way that, on the one hand, in the case of I @ roplasts hardening in the plasticizing device is reliably avoided, on the other hand However, the curing takes place in the korm in a very short time, una that with Thermoplastics the temperature of the melt at the lower limit of the plastic range can be maintained, resulting in the shortest possible cooling times.

In addition, there is the further advantage that the normally *) males The amount of raw material required for the sprue is saved or in the case of thermoplastic compounds reprocessing is not necessary. It is also advantageous that moldings are formed produce with marking-free surfaces.

When working continuously by means of a worm *) Preparation the volume of the portions can expediently depend on the speed of the screw and the speed of the downstream separating device. The same can be done in a discontinuous manner by means of a screw-piston device depending on the size of the outlet opening and the advance of the screw piston take place, a wide cutting knife arranged in front of the discharge opening as Can serve closure for the outlet opening.

There is a device for carrying out the method according to the invention provided, which is gekemzzeiclmet by a plasticizing device known per se with horizontal or downward directed, preferably the contour of the one to be produced Fonn.körpers adapted discharge opening and with one of the discharge opening downstream at least single-edged reciprocating or rotating cutting device and a subsequent bogie with two or more for receiving the at least two-part tool molds determined in the rotational speed infinitely adjustable turntables.

Since the times for the hardening process are sufficient cooling of the thermoplastic The mass or the times for sufficient heating of the thermoset for hardening The turntable is largely determined by the shape of the molded body of course with such a number of tool shapes or mold cavities provided that the molded parts are ejected from the tool nests in a dimensionally stable manner can before the turntable has completed a full revolution. To get an optimal To achieve operation, this of course also requires that the output the plasticizing device with the speed of the turntable in the correct ratio stands. The temperature control medium is supplied in accordance with the proposal of the invention expediently through the axis of the turntable. It goes without saying that this is the case also provide that the temperature control medium is controlled so that it is the appropriate Mold cavity always flows in when the turntable is in the correct position or from it drains.

According to a further proposal of the invention, the male and / or female part of the tool molds hydraulically, pneumatically or mechanically to adjust. The adjustment movement can expediently by means of cam tracks or Cams take place, for example, with the cavity having the mold Turntable and another turntable work together so that they are always in Overlap the area of at least one of the mold cavities in an exactly fitting manner.

Is directly or indirectly connected to the further turntable between this and the turntable for each mold cavity, which exits the mold cavities a stamp or a corresponding tool part is arranged, the stamp or Tool parts work together with a cam attached to the other turntable, so that the closing and reopening of the mold is effected in each case. Of course have the turntable also appropriate facilities for controlling the time of the so-called holding pressure, temperature control and demolding. And furthermore can according to a proposal of the invention, the turntable also with a J3enzungseinrichtung be provided.

In some cases, for example with crown caps for bottles it may be desirable or necessary to incorporate prefabricated parts into the molded parts. For this purpose, the invention provides that the turntable with a possibly with a upstream sorting device provided feed device work together, these feeding devices of course depending on the number of turntables or which is formed accordingly on these mold cavities.

The closing time and the closing pressure of the molds are expedient controlled depending on the speed of the turntable. Of course it plays the number of tool nests on the turntable plays an important role.

By choosing the turntable diameter accordingly, you have it with you the opportunity to focus on achieving the best possible relationship nits To influence.

In the event that burrs are to be expected on the molded parts, the invention provides that deburring devices in the area of the turntable be provided, for example grinding wheels, cutting devices, brushes Od. Like. With which the moldings that are still in the mold can be deburred. Likewise, in the event that the moldings are to be printed or embossed, provided to arrange appropriate facilities in the area of the turntable, so that the molding still in the mold can be processed accordingly.

According to a further proposal, the invention provides for the application of the Method according to the invention and the device for crown closures made of thermoplastic Plastic for bottles in front.

It should be based on the well-known elastic property of the material Use is made in such a way that the edge of the crown clasp is in relation is formed on the bottles with undersize and ribbed so that a Long-term mechanical stretching at least almost completely disappears. It can be provided that the crown closure is provided with a sealing insert, which are either molded in one piece or made and inserted as a separate part can be.

For easier handling bplmm closing the bottles on the The filling system can replace the material of the crown closure with metallizable metal, preferably in the form of dust.

In practice it has been shown that depending on the swelling behavior of the to Processing coming melts the dosed quantities for the preform differ can be, whereby in the deformation tools possibly overflow holes or pinch edges can be provided. Comes with multi-part refrigerated or heated molds deform the raw material, so can the arrangement of the punch or tool parts for the closer angeodnet underneath the turntable In the case of screw closures with internal threads, for example, the individual The stamp is provided with gears, by means of a curved Zalin rod d ,, n unscrewing process effect with rotating plate.

It is not uncommon for air inclusions awlf, especially in pressed parts, which thereby largely avoided the controllable retraction of the press ram can be. Ventilation for the purpose of undesired amounts of gas is also possible through a Cam control possible.

Are they relatively small and in large numbers? Molded parts to be produced, the diameter of the turntable can be correspondingly large **) a corresponding number of hollow nests can also be selected on the turntable be provided so that it is possible to use several independent To feed plasticizers. This results in the possibility of e.g. first close a thermoset closure on the first half of the turntable manufacture, after unscrewing, for example, the threaded punch in a the second cycle arrives, where it is locally wetted with welding aids and underneath the second plasticizing device is transported, from which another preform, E.g. from foamable soft PVC, which is then profiled with one Stamp is formed in the closure to form a seal. Depending on the size of the molded part further plasticizing units can also be arranged.

For example, multi-colored articles or moldings, consisting of different raw materials.

Essential items such as crown locks can be made of impact-resistant Xlart-PVC can be produced according to this Alethocle, whereby the ribs are deformed in this way that a slight excess of the bottle mouth is the prerequisite that when pressing the crown locks on the bottle neck only a slight Short-term stretching per rib occurs and by a second, internally attached conical lip seal seals the bottle tightly. Engravings on de @ Dechelflä @, e.g. @n @ rschlü. en, can ehenfil on) int f - *) 1 '' Turntable arrangement can be printed or embossed in color at the same time.

The holding pressure and the cooling time can be reduced by the cam disk arrangement can be chosen arbitrarily, but with continuous charging of the mold cavities on the one hand takes place and on the other hand the output of the rotation speed and the plasticizing capacity is determined. In the case of a plurality of deformation stations, large numbers of items are required to achieve. Very weakly stabilized hard and soft PVC mixtures, polyvinyl fluoride, Post-chlorinated polyvinyl chloride and polyvinylidene chloride are continuous The operation of the plasticizing device is easy to handle from a thermal point of view.

The invention is shown in the drawing in one embodiment and is explained on the basis of this in the following.

1 shows, in a schematic representation, a device for Implementation of the method according to the invention, FIG. 2, on a somewhat larger scale a detail in a slightly modified form and FIG. 3 a further detail.

According to Fig. 1 are on the turntable 1 as it were in development However, in reality, the mold cavities 2 shown are arranged on a circle. Above the mold cavities are the axially displaceable guided in the blocs 3 and arranged by means of the cam 4 via the rollers 5 controlled tool stamp 6.

The preplasticized in the screw or screw-piston injection unit 7 warm mass is released from the Euse by means of the motor 8 operated cutting knife 9, which may also act as a lock for the unit 7 or whose outlet opening can serve in the Servings 10 divided into a predetermined volume, the division in accordance with the Dre speed of the turntable 1 takes place so that each one serving over the feed 11 into the one located just in front of the outlet opening or diioe 12 Mold cavity 2 is reached During one rotation of the turntable 1, the mold cavities pass through 2 the positions I to VI, i.e. in position I the portion 10 is filled, in position II is about the cam 4 and the roller 5 of the punch 6 to a large extent moved back, in position III the molding is pressed, the pressing pressure up to to position IV or even a little further is maintained or even still can be easily reinforced, in position V is the punch 6, which by the only schematically indicated spring 13 is always pressed the cam 4 via the roller 5 is extended together with the now finished molding from the mold cavity 2 and is ejected in position VI or stripped from the punch 6. While running Of course, the temperature in the various atellations is in each case Required influences what is most expedient in a manner not shown through the shaft of the turntable 1 or the turntable 6 and the mold cavities 2 he follows.

Always after a molding has been ejected or removed in position VI.

stripped off Yiurde, the Fornnest 2 runs back into position I, where the process is repeated. Be during one revolution of the turntable so all mold cavities 2 filled once with a portion 10, since during this circulation yes, each of the mold cavities present on the turntable close once in front of the nozzle 12 stand comes.

Of course, the number of Fpr, mester 2 shown here is the same how the type of control of the punch 6 should be understood and could only be an example can also be done in a significantly different way. such as can be provided be that the finished pressed molding remains in the mold cavity and d in the molding in a further position another mass is introduced, for example um in the for @ ling a seal or a to train different colored insert or the like .. Here it goes without saying that, depending on the requirement of the Turntable is provided with a more or less large number of mold cavities, so that during one revolution of the turntable all the measures provided work properly have it carried out.

According to 5. 2, the tool punch 6 is at its lower end for the purpose of Manufacture of screw caps with the thread 14 provided. Here must then, of course, care must be taken that when low and high of the stamp or when the finished screw cap is deployed, either the Stamp or twist the cap loads. In the present case this is because of this brings about that the punch 6 in the Führbü.'chse 15 is both axially displaceable is also rotatably mounted and that the guide bushing 15 in turn is axially is arranged displaceably in the sleeve 3. The guide bush is supported here 15 by means of the spring 16 on the bushing 3 and the punch 6 by means of the somewhat weaker Spring 17 on the guide sleeve 15 so that-the Fiihnungsbüchse 15 and the punch 6 must always be pressed in the direction of the cam 4.

In the manufacture of the crown lock 18 of FIG. 3, the tool stamp is designed in several parts, namely in 3 parts.

As shown in the left half of the figure, parts 19a and 19a serve 19b in connection with the mold cavity 2 to form the central part of the bottom and the rib-like ring seal 18a and the parts 19b and 19c in turn in connection with the Fonnnest 2 to form the outer part of the floor and the outer edge. The division of the stamp into parts 19b and 19c is particularly important for this reason made to after the final pressing and sufficient cooling or in the case of thermosets, sufficient curing of the molded part is still possible to be able to extend the molding located on the punch out of the mold cavity and then after returning the guide sleeve 15 by advancing the part 19c, the crown lock while temporarily stretching its edge over the curved end 19d of the stampelis 19b to slide.

Claims (13)

P a t e n t a n s p r ü c h e 1. Process for the production of moldings made of thermoset or thermoplastic Plastics, preferably made of thermoplastic plastics, d a d ii r c h g e k e n n z e J c hn e t that the raw material as gently as possible in the plastic Condition brought, precisely dosed, continuously plasticized, deformed and is hardened or cooled. 2. The method according to claim 1, characterized in that the volume of the portions as a function of the speed of the screw plasticizing device and the speed of the cutting device is measured. 3. The method according to claim 1, characterized in that the volume ' of the portions as a function of the feed rate of the screw or the Schneeken piston device is measured. 4. Device for performing the method according to one of the claims 1 to 3, characterized by a plasticizing device known per se horizontal or downward preferably the contour of the to be produced Shaped body adapted outlet opening, as well as with one downstream of the outlet opening at least one reciprocating or rotating cutting device and a subsequent bogie with two or more for the inclusion of at least two-part tool molds determined in the rotational speed infinitely adjustable turntable. 5. Apparatus according to claim 4, characterized in that the turntable with a device guided through its axis n h for alternating Heating and cooling of the tool molds are provided. 6. Performing according to claim 4 or 5, characterized gekennzeic @ net that the male and / or female part of the tool @ forms hydraulically, pneumatically or is or are mechanically adjustable. 7. Apparatus according to claim 6, characterized in that the adjusting movement takes place by means of cam tracks or discs. 8. Device according to one of claims 4 to 7, characterized in that that the turntables are provided with a wetting device. 9. Device according to one of claims 4 to 8, characterized thereby, that the turntable for the purpose of loading the Drmnester with prefabricated parts a feed device optionally provided with an upstream sorting device work together. 10. Device according to one of claims 4 to 9; characterized, that the closing time and the closing pressure of the molds are dependent on the speed of the turntable is controlled. 11. Device according to one of claims 4 - 10, characterized in that that in the area of the turntable devices for deburring which is still in the open Moldings located in the vehicle are arranged, for example SchZiS disks, Cutting device or the like. 12. Device according to one of claims 4 to 11, characterized in that that in the area of the turntable facilities for printing or embossing of the still are arranged in the opened tool phone located moldings. 13. Application of the method and the device according to the preceding claims for crown closures made of thermoplastic plastic. 14. Crown closure according to claim 13, characterized he one in diameter undersized from en and with Ribbed edge up from a b? I short-term ger mechanically ung sic'i at least approximately in his - Original shape restoring material is made.