DE2410085A1 - METHOD AND DEVICE FOR MANUFACTURING ORIENTED HOLLOW BODIES AND ORIENTED HOLLOW BODIES - Google Patents

Description

Or.EMsBEBiüipl.-ta & W.fflsnsnn O A 1 Or.! §.Ste * jii.rE; 2.-fc5.Π.Csrs & anil ** ♦ ^ι

Patsntanv.-ällo
Hamburg 50 - Königstrasse 28

W. 26 185/74 2o / Co

28, 2.

Emery I. Valyi

Riverdale, New York (V.St.A.)

Method and device for producing oriented hollow bodies and oriented Hollow body.

The invention relates to blow molding plastic articles from a preform. Of the The main purpose of the invention is to provide an improved, hollow, oriented article.

There are various methods and apparatus for making plastic blow molded articles known from a preform, for example from US Pat. No. 3,349,155 and Re.-Issue-PS 27 1o4. In general these known methods are by molding a preform in a preform on a blow core Placing the molded parison and the blow core in a blow mold and expanding the parison marked within the blow mold by means of a working medium.

Of course, the blowing process itself creates an orientation in the plastic as a result of a radial extension, however, it is highly desirable to also orientate in the axial direction to create. Heretofore, this has been done by reheating or reheating the preform and was axially oriented, for example by stretching, prior to inflation.

Such known methods have disadvantages. A very particular disadvantage is the difficulty in finding a

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maintain uniform wall thickness. The control of the wall thickness distribution is obviously quite especially significant. Other difficulties with known methods include insufficient control of the Dimensions of the preform and the degree of orientation, the time required and the uncomfortable work processes as disadvantages.

Accordingly, it is a primary purpose of the invention to provide an improved oriented hollow article and to provide an apparatus for making this item.

Another object of the invention is to provide a method and an apparatus for producing the above to create said object, which is simple and easy to use, easy to operate economically are to be adapted and which result in an improved / oriented, hollow object.

The invention provides a method for producing hollow objects which, in the axial, oriented in the radial and tangential directions and made of a malleable "plastic material," the method comprising the steps of: injecting a preform in a preform onto a Blow core in an injection molding station, arranging the blow core with the preform on it outside the Injection station, partial. Expanding the preform to remove it from the contact surface with the blow core to free, axial extension or lengthening of the preform and finally expanding the preform by working means to produce the hollow object.

If it is desired to produce a multilayer or multi-layer parison, the blow core is used first provided with a layer of a plastic, and next is another plastic

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pressure-molded around them or injected under pressure, which is, for example, according to the teachings of U.S. Patents 3,349,155; 3,717,544; and 3,719,735. Although the following description is mainly relates to preforms, it goes without saying that the method and the device according to the invention also apply to such multi-layered preforms can be applied.

The device according to the invention has a preform in which there is a blow core, means for introducing deformable plastic into the preform to form a preform on the blow core to form a preform station for partial expansion of the preform, a device for positioning the blow core with the preformed parison on the blow core at the preform station, means for partially expanding the preform in the preform "station" to free it from surface contact with the blow core, a device for axial expansion or lengthening of the preformed parison, a blow mold having a mold cavity to mold the inflated article therein, the blow mold can also serve as a preforming station, a device for introducing the axially elongated, preformed Parison in the blow mold and means for inflating the parison in the cavity around the blown Object to shape.

It is readily apparent that the cave article according to the invention by in the highest degree improved properties due to the fact that its walls can be controlled both in the axial, which is oriented in the radial as well as in the tangential direction. It is known that the Orientation, the remarkable properties of plastics, for example the transparent

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speed or clarity, the impact or impact resistance, the strength and resistance to passage or permeability, etc., are significantly improved. Among the plastics that can be improved in this way are polystyrene, PVC, polyolefins such as PE and PP, polyesters, polyamides, acrylic compounds, acrylonitrile compounds and methacrylonitrile polymers. The controlled orientation in the axial, radial and tangential directions, which characterizes the article according to the present invention, therefore offers remarkable advantages which can be obtained in a simple and easily executable manner.

The invention is explained below with reference to the drawing, for example.

Fig. 1 is a front view, partly in section, showing the blow core in the parison forming station shows in the preform.

Figure 2 is a view corresponding to Figure 1 showing the blow core withdrawn and the preform shows on the spot «

Figure 3 is a view corresponding to Figure 1 showing the blow core in place in the preform shows the preform being preformed.

3A is an enlarged cross-sectional view showing the blow core and preform according to FIG Fig. 3 reproduces.

FIG. 4 is a representation corresponding to FIG. 1, in which the blow core is drawn back and the preform is shown axially elongated. FIG. 4A is an enlarged cross-sectional view showing the blow core and preform shown in FIG. 4.
Fig. 5 is a representation corresponding to Fig. 1,

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which shows the blow core in the blow position in the blow mold, the axially elongated Preform is inflated.

• Fig. 6 is a representation corresponding to Fig. 1, the blow mold in the unloading or removal position and the blow core in its retracted position Location shows.

Fig. 7 is a view showing an article made according to the invention. In the drawings, a preform is denoted by 1o and has outer wall parts 11 which are designed to be separable, which is of the shape and shape of the Preform depends to form the outer surface of the preform walls. The preform 1o also has a End wall portion 12 which is shaped to the end wall of the preform. The end wall 12 of the preform 1o has an injection port 13 which is an injection nozzle 14 appropriately receives through which plastic material is injected into the preform 1o. The preform 1o is shown split so that it can be opened to reveal the preform formed. As before the plastics to be taken into account and their properties according to the invention are established can be improved by orientation, polyolefins such as PE, PP and copolymers of these, PVC, polystyrene, acrylonitrile, Methacrylonitrile, polyvinylidene chloride compounds, Polycarbonates, polyesters, polyamides, etc.

In the case of making multi-layer preforms, the layers of which are made of different plastic materials must have the deformation characteristics all layers are taken into account, such characteristics being known to the person skilled in the art, and the stage of axial stretching or elongation must be carried out in such a way that it at the same time is appropriate or suitable.

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A blow core 15 'which is carried on a rod 16 is arranged in FIG. 1 within the preform 10 and is formed with a cylindrical surface 17 and an end wall 18 in order to with the walls 11 and 12 of the preform 1o to form a preform chamber in FIG which the preform is molded. The blow core 15 is provided with the usual blow passages 19 for insertion provided by pressure means to expand the preform into the shape of the finished article. Of the Blow core 15 has a front part 15a and a rear part Part 15b, the front part 15a being axially movable to and fro by means of a piston rod 2o which is moved by suitable means, not shown, as is most clearly shown in Figs 4A is shown in a manner described below. A blow core rod 16 is connected so that them by a crosshead or crosshead 44 and a convenient hydraulic cylinder for advancing and can be actuated to retract the blow core 15 in its various divisions of work.

A neck ring, which can be formed in two parts, is composed of parts 52 and 53 which are attached to one Carrier 51 are attached, which is connected so that it is through a socket 6o, a cross head 61 and through an appropriate piston / cylinder device (not shown) connected to the cross head 61 can be displaced can. The neck ring is at the preform injection station arranged in the preform injection position adjacent to the walls of the preform 1o and is designed so around the neck of the preform and the resulting blown article. A preform 21 is formed with a cavity 22 which is shaped so as to provide a boundary or a contact surface for the Partial expansion of the preform in the preform station to accomplish. The preform 21 has an opening 24 on its

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one side to receive the blow core 15. A blow mold 25 is provided in a corresponding manner, which is provided with a cavity 26 which is designed to accommodate the finished article, for example a bottle 23, to shape. The blow mold 25 also has an opening 27 on one side, to receive the blow core 15 and the preformed parison. Of course, the preform 21 and / or the blow mold 25 may be formed in one piece, or they can be split, in two pieces, if this is desired to be carried out. In addition, the separate preform 21 can be omitted if so desired and the preform can be inserted directly into the blow mold 25 and the preforming process can be done on the blow mold.

Fig. 1 shows the parts in the preform injection station, wherein the blow core 15 within the preform 1o and the neck ring carrier 51 adjacent to Preform 1o are arranged and both the preform 21 and the blow mold 25 are arranged outside the path of the blow core 1o. If the parts are in this Location, plastic material will pass through the nozzle H is inserted into the injection cavity to form the preform 31.

In the second stage, which is shown in Fig. 2, the preform 1o is open to the preform and to expose the blow core with the neck ring, and the preform is sufficiently separated therefrom to expose To create space for the preform 21, which then moves in the transverse direction in the path of movement of the blow core will. It is understood that changes in these movements can be made by those skilled in the art can be made easily. Accordingly, instead of the blow core alone, it can be moved in the axial direction is to be rotatably attached to the blow core and from the

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Injection station to preform station and blow molding station be moved.

In the third stage shown in FIG. 3, the blow core with the neck ring is moved into the preform 21 and working fluid is introduced through the blow core passages 19 under pressure to the preform to partially expand so that it is freed or separated from the contact surface with the blow core, as can be seen most clearly in Mg. 3A. The purpose of this stage is what has already been mentioned To avoid difficulties that would arise during the axial elongation of the preform, if this is in contact or surface contact with the blow core. For example, if the preform is stretched in the axial direction while it is in surface contact with the blow core, the latter tends to do so in local areas due to the inhibition caused by friction against the wall of the blow core will, to dilute. This leads to undesirable and unpredictable thinning or wall thickness reduction, which often leads to unacceptable products.

Of course, a preform could sometimes be dispensed with at this stage and the preform could be preformed without obstruction or resistance by controlling the duration and / or the level of the working fluid pressure. Alternatively, this step can be carried out in the blow mold, the preform first being preformed within the confines of the blow mold without expanding it in conformity with the blow mold. The preform is then elongated axially to reach the length of the blow mold cavity and only then is it expanded or inflated into full conformity with the blow mold.

In the fourth stage shown in Fig. 4, the preform is axially moved by moving the front part 15a

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of the blow core 15 in the axial direction through the piston 2o, as best seen in Figure 4A, elongated. Alternatively, if desired, the same .effect could be obtained can be achieved by moving the entire blow core 15 in the axial direction. This stage will make you more comfortable Way the preform is stretched lengthways before inflation without the above problems occur, and thereby orientation in the axial direction in addition to that subsequently becomes through Inflation generated orientation generated. It can be seen that preheating is not required and Discontinuities caused by friction are avoided «At this stage, both the preform and the Blow mold arranged at a distance from the blow core.

In the Mg.5 fifth stage shown the blow core with the collar and with the axially elongated pre- * is molded in the blow mold 25 are arranged and pressurized befindliches working medium passages blow core is fed through the to the preformed and axially elongated preform in the Blow mold cavity 26 to form bottle 23. Depending on the shape of the preformed and axially expanded parison, it can be brought into position through the neck opening of the blow mold, or the blow mold can be opened to allow the parison to be introduced.

When the object has cooled to its correct state, the neck ring parts 51 and 52 are separated from each other separated, the neck ring carrier 53 is withdrawn and the blow mold is out of the path of movement of the blow core into the removal position, as shown in Fig. 6, pushed out, in which the finished object is removed from the blow mold. During the removal stage, the blow core is transferred to the preform forming station returned for the next duty cycle.

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The removal of the object can be facilitated by using compressed air or by mechanical actuation parts are, for example, by ejector pins, which are effective through an opening 88.

It can be readily seen that the finished article according to the invention is characterized by many advantages is. In particular, the side walls are in a controlled manner in the axial, radial and oriented in the tangential direction without any longitudinal irregularities occur or Wanddickeverrederungeη available. Furthermore, the article according to the present invention has a substantially uniform Wall thickness on. The uniform wall thickness of an object oriented in this way is highly beneficial.

As part of the method according to the present invention it is possible to include the stages of the axial and / or perform radial orientation at temperatures that are appropriate to get the best properties in a given To produce plastic. Accordingly, a cooling period or a cooling time between the axial lengths or extending the preform are introduced. As an alternative, it can be the preform or predetermined Areas of the preform are warmed up or heated in order to reduce the degree of orientation in these areas.

Of course, the present invention is very versatile and a wide variety of objects Variable configurations can easily be made. If desired, the present Invention can be carried out on a continuous basis or intermittently. For example, the process be interrupted at any convenient stage, the item can be saved or transferred to one be brought to another place, and the manufacturing

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Drive can then be completed, moving the preformed preform from one to the other Place can be brought

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Claims (22)

Claims (1 Method of making oriented hollow Plastic articles comprising injection a preform into a preform onto a blow core in an injection station, the positioning of the blow core with the preform on it outside the spraying station; partially expanding the preform to remove it from surface contact with to free the blow core; the axial stretching of the preform and the final stretching of the preform by working equipment. 2. The method according to claim 1, characterized in that that the preform is arranged outside the injection station in a preform station and at this is partially expanded. 3. Method according to one of Claims 1 or 2, characterized in that the axially elongated preform is arranged in a blowing station and is finally expanded there. 4. The method according to any one of claims 1 to 3, characterized in that the preform by working means is partially expanded. 5. The method according to any one of claims 1 to 4, characterized in that the preform by the axially extendable blow core is axially elongated or partially stretched. 6. The method according to claim 5, characterized in that the preform by an axially reciprocable Part of the blow core is elongated. / 7. Procedure according to one of Claims 1 to 6, characterized in that the preform is cooled prior to being axially elongated. 8. The method according to any one of claims 1 to 7, characterized in that the preform before axial lengths is heated or heated. 409839/0656 9. The method according to any one of claims 1 to 8, characterized in that "certain areas of the Preforms are heated or heated before the axial length or stretching. 10. The method according to any one of claims 1 to 9 »characterized in that the neck part of the preform is held enclosing or held while the preform is partially expanded, axially is elongated and finally expanded or inflated. 11. The method according to any one of claims 1 to 1o, characterized in that the article produced oriented in the axial, radial and tangential directions will. 12. The method according to any one of claims 2 to 11, characterized in that the EncU expansion stage is carried out at the preform station. 13 · The method according to claim 4, characterized in that the preform without resistance or compulsion to Part is expanded by the working medium pressure in relation to its duration of action or to its level or is controlled with respect to both. 14. The method according to claim 1, characterized in that a multi-layered preform on the blow core is formed. 15. Apparatus for making oriented objects Made of plastic, consisting of a preform with an outer preform part and a blow core with walls, which shape the inner surface of the object; a device for introducing plastic into the Preform for molding the preform on the blow core; a preform station for partially expanding the preform j a device to the blow core with the preform formed thereon and the preform station to be arranged opposite one another; a facility for 'partial Expanding the preform at the preform station, 409839/0656 -H- to keep him from surface contact with the blown core to free; means for axially expanding the preformed parison; a blow mold with a Cavity for molding the blown article; one Device for introducing the axially elongated preformed parison into the blow mold and from a device for inflating the preform into the cavity to form the finished article. 16. The device according to claim 15, characterized by a neck ring (52,53) and means to to arrange the neck ring with the blow core (15) »the preform (21) and the blow station (25) opposite one another. 17. Device according to one of claims 15 or 16, characterized by a device sum removal dea blown object (23) from the blow mold (25). 18. Device according to one of claims 15 to T7 » characterized in that the preform station has a chamber (21) with a cavity (22) in it. 19- device according to one of claims 15 to 18, characterized in that the blow mold (25) is also used as a preform station (21). 20. Hollow body made of plastic with a bottom wall, Side walls and a neck part formed in one piece with these with an opening therein, characterized in that the walls are controlled in the axial, radial and tangential directions are oriented. 21. Hollow body according to claim 2o, characterized by a substantially uniform wall thickness. , 22. Hollow body according to one of claims 2o or 21, characterized by more than one layer of plastic. 409839/0656