JPH01314112A - Resin selector - Google Patents

Abstract

PURPOSE:To contrive a reduction of a quantity of residual resin within a head die by performing a changeover operation of the resin simply in a short period of time at the time of changeover by providing a changeover member movably and fixably to a connecting member and a discharge port member of an extruding machine. CONSTITUTION:A changeover position 45b of a changeover member 40 and discharge port members 34, 35 are fixed respectively to a connecting member 20 and changeover passages 47b, 48b of the changeover member 40. When extruding machines 30, 31 are operated in this manner, two kinds of resin are supplied to resin paths 11, 12 through the passages 47b, 48b and extruded through an annular discharge port 13. Then after suspension of operation of the extruding machine, the members 34, 35, 20 are removed from the member 40, the member 20 and the member 34 or 35 are joined respectively to changeover position 45b or 45c of the changeover member 40 and the changeover member 40 and operation of the extruding machine on only a junction side is reopened. With this construction, the resin is entered into the resin paths 11, 12 by passing through a branch possage 46a or 46c and the individual resin is extruded through the discharge port 13.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention mainly relates to a head die for extruding a parison for blow molding, which is connected to a plurality of extruders. The present invention relates to a resin switching device for an extruder in which a switching member is provided between the molding die and the switching member is moved and attached depending on the purpose.

(Prior art) In conventional extruders that extrude a single parison using two extruders, in order to use resin from one of the extruders, a sliding die installed in the head die must be moved. A device that closes or controls one cylindrical resin path in the head die, or a device that opens and closes a shutoff valve for the resin path between the head die and the extruder, or supplies the resin to two extruders. Methods such as replacing the raw materials themselves are being adopted.

(Problem to be solved) However, in the case where the head die is equipped with a sliding die that serves as a switching valve, the cylindrical resin path structure in the head die becomes complicated, and the residual resin on the non-supply side gradually leaks. The quality of subsequent molded products deteriorates, and the residual resin remaining in the RAD die is exposed to high temperatures for a long period of time, so the quality deteriorates and it cannot be used at all at the next changeover, so it is extruded and discarded. However, the complexity of the resin path and the deterioration of quality tend to hinder the flow, and in order to ensure completeness, the resin must be disassembled and cleaned.

In addition, even in devices that are switched by a gate valve, the resin remaining on the downstream side of the gate valve is not equally partitioned with the resin on the other side, so these residual resins may get mixed in.
This still results in a decrease in quality, and the residual resin deterioration is similar to that of the prior art described above.

In addition, for products that do not have any switching device and change raw materials,
Both the extruder and the head die must be disassembled and cleaned, which requires a great deal of labor and time, and the operating efficiency of the apparatus is significantly reduced.

Therefore, these prior art methods are inefficient in molding small lots, especially in trial molding of various products on an experimental basis, and a large amount of resin is wasted, resulting in extremely high costs.

In addition, in multilayer parison molding, the extruded residual resin that occurs when changing materials is a mixture of different materials, so it can only be used for recycling low-quality molded products, and it can also be used as a resin contaminant that deteriorates quality. However, reducing the amount of extruded residual resin as much as possible will greatly contribute to lowering costs in small-lot production.

This invention aims to improve the prior art as described above, and by adding a simple component with a simple resin path, it is unnecessary to clean the head die or extruder at the time of switching, and the work of changing the resin is reduced. The purpose of this is to provide the market with a device that is easy and quick to use, minimizes the amount of resin remaining in the head die, allows frequent switching operations, and minimizes the loss of resin that occurs during switching. do.

(Means for Solving the Problems) In order to achieve the above-mentioned problems, at least two internal and external cylindrical resin paths are provided in the parison head die, and these paths merge on the downstream side to form a single annular discharge port. The upstream end of each cylindrical resin path is independently connected to a resin supply port provided on the outer peripheral surface of the die, and the upstream end of each cylindrical resin path is independently connected to a resin supply port provided on the outer peripheral surface of the die. Through a single resin path connecting member in which resin communication paths are arranged in parallel,
The resin supply port of the die can be connected to a discharge port member of an independent extruder, and the upstream ends of the resin communication passages of the resin passage connecting member are provided adjacent to each other, and the resin passage connecting member A single resin path switching member is provided between the upstream end of the extruder and the discharge port member of each extruder, and this resin path switching member has different combinations of branching or communicating paths at each switching position. The resin switching device is characterized in that switching passages are formed respectively, and the switching member is provided at each switching position so as to be movable and tightened with respect to the connecting member and the discharge port member of the extruder. This solved the problem.

In order to achieve the above object, in the resin switching device of the present invention, the shapes of the switching passages at each switching position are different from each other,
One of the switching positions is provided with a parallel switching resin path that connects each extruder discharge port and each resin communication passage of the resin connection member in parallel, and at least one other switching position is provided with a parallel switching resin path that connects each extruder discharge port and each resin communication path of the resin connection member in parallel. Block the outlet, branch from the switching resin connected to the discharge port of an extruder other than the blocked extruder, and form a branched resin path at a position communicating with the resin communication path corresponding to the blocked extruder. It may also be characterized by including a branch switching resin path.

In order to achieve the above-mentioned object, in the switching device of the present invention, the resin path switching member is a bar-shaped member whose cross section has the same contour shape, each switching path is provided almost in a direction perpendicular to its length, and each switching path is provided in the vicinity of each switching position. In some cases, the screw holes for tightening with the resin path connecting member are provided, and several screw holes are provided around the switching passages that connect with the discharge port member of each extruder. .

(Function) In the apparatus of the present invention configured as above, for example, when connecting the discharge ports of different extruders to each cylindrical resin path in the head die as the most general method, the resin path switching The member is aligned with the upstream end of the connecting member at a switching position where switching resin passages are provided in parallel as many as the number of cylindrical resin passages, and the connecting member and the switching member are tightened and fixed.

Then, a discharge port member of an extruder is pressure-bonded to the primary side of the switching member, and this discharge port member is tightly fixed to the switching member.

In this way, the head die, the connecting member, the switching member, and the extruder are all maintained at a predetermined temperature and operated, and parisons having different inner and outer layer materials (resin color and/or material) are extruded from the head die.

Next, in order to change the thickness of each resin layer formed as a parison, the discharge amount of each suppressor is changed in accordance with the thickness. Alternatively, the flow rate is separately controlled by a flow control valve provided on the connection member.

That is, to increase the thickness, increase the discharge rate ratio of other extruders, and to decrease the thickness, conversely, decrease the discharge rate ratio.

Next, using an example of a machine with two extruders, if you want to stop the supply of resin from one extruder and only extrude the resin from the other, stop the operation of all extruders once, and then For extruders, the temperature is also reduced.

Then, the fixing means of the discharge port member of each extruder is released and the switching member is moved away from the switching member, the switching member and the connecting member are released, and the switching member is moved away from the switching member and the connecting member. Move it to the desired switching position, tighten and fix the switching member to the connecting member again, press only the extruder on the supply side to the newly selected switching position of the switching member, and tighten and fix it using the fixing means. .

In this way, the resin from the combined extruders is branched into two resin paths by the branch switching resin path in the switching member, and the same type of resin is supplied to each resin path communication path in the connecting member. The resin that has been supplied up to the communication passage and the cylindrical resin path in the head die is extruded, and then a single resin parison is extruded.

On the other hand, when molding only the resin in the opposite extruder, the same operation is performed by moving the switching member to a position suitable for another purpose.

When it is desired to return the extruder to its original position, the extruder is operated in a similar manner, raising the temperature of the extruder that had been stopped to a predetermined temperature.

(Effects) Although this invention is constructed and functions like a savior, there is no need to provide a resin switching structure in the head die, and the structure of the molding die is a head die having a simple multiple cylindrical resin path that can mold a multilayer parison. can be adopted, the amount of residual resin at the time of resin switching can be reduced, and cleaning of the rad die after each switching can be omitted.
The apparatus of the present invention can also be constructed by adding a connecting member and a switching member to a conventionally used molding die of this type.

Also, the resin that is extruded as unnecessary resin during switching is only the amount from the resin communication passage in the connecting member to the cylindrical resin path, and the resin in the switching passage from the extruder to the switching member can be left as is and unnecessary. The amount of resin extruded is small and the yield is good.

Further, since the resin in the head die extruded as unnecessary resin has not been heated to high temperature for a long period of time, the quality does not deteriorate that much, and it can be used sufficiently for recycling products whose quality has slightly deteriorated.

In addition, the switching work is relatively simple: releasing the tightening device, separating the extruder outlet member, moving and re-tightening the switching member, and press-fitting the extruder outlet member. There is no work involved, and it can be done easily and in a short time.

Therefore, in small lot production or trial molding, various moldings such as material exchange and multiple molding can be changed over in a short time, improving the efficiency of these operations and reducing the amount of resin discharged.

(Example) Next, a typical embodiment of this invention will be described.

In FIG. 1, reference numeral 10 denotes a die head, which is assembled from a plurality of parts, and in which double cylindrical resin passages 11 and 12 are formed concentrically in the figures. They merge on the downstream side to form an annular discharge port 13, and the upstream ends of each cylindrical resin path 11.12 are independently connected to resin supply ports 14.15 provided on the outer peripheral surface of the die head 1o. radial resin path 16.17 leading to
It is communicated by.

Reference numeral 20 denotes a connecting member, which has the same number of resin communication passages 21.22 as the cylindrical resin passages 11.12, and the positions of the downstream ends of these passages are aligned with the positions of the supply ports 14.15 of the die head 1o. They are formed parallel to each other and close to each other on the upstream end face 25, and in the embodiment, they are formed of a metal block similar to the Herad die 10, and are firmly established by several bolds per 1° of the head die. It has been done.

In FIG. 2, 3o and 31 are independent extruders, and discharge port members 34 and 35 provided with discharge ports 32 and 33 are respectively attached to support members.

The discharge ports 32 and 33 are screwed together so as to be movable and fixed in the axial direction by a slight distance of about 10 to 20 III, and these discharge ports 32 and 33 are provided at positions close to and facing the upstream end surface 25 of the connection member 20. Yes, one discharge port 32, one resin communication passage 21 of the connecting member 20, and the other discharge port 3
3 and the other resin communication passages 22 are provided in the same plane, and although the discharge ports 32 and 33 are provided in different directions by 90 degrees in the illustrated example, they are parallel to each other. Even if the angle is different, there is no difference in this invention.

Reference numeral 40 denotes a switching member, and in the illustrated example, it is composed of a single rod-shaped block with a pentagonal cross section, and one ridgeline 4 of the switching member 40 is a switching member.
The included angle between 1 and 1 is 90°.

This switching member 40 is provided slidably in the length direction with respect to the guide portion 26 provided on the connecting member 20,
For example, it is movable relative to the connecting member 20 and the outlet member 34, 35 by means of a feed screw 27.

The surface 42 that is farthest from the ridgeline 41 is in contact with the upstream end surface 25 of the connecting member 20, and one inclined surface 43 across the ridgeline 41 is connected to the first extruder 30.
The other inclined surface 44 sandwiching the ridge line 41 serves as the joint surface of the discharge port member 34 of the second extruder 31.
Several switching positions 45a, 45b, 45c are provided along the length of the switching member 40, which serves as a coupling surface for the switching member 40. 46c is bored.

To be more specific, at the central switching position 45b,
A bent communication passage 47b connected to one resin communication passage 21 of the connecting member 20 is formed to penetrate through the inclined surface 43, and a bent communication passage 48b connected to the other resin communication passage 22 of the connection member 20 is formed. , and are provided to penetrate through the other inclined surface 44.

These communication passages 47b, 48b are open to the surface 42, and these communication passages 47b, 48b constitute a parallel switching passage 46b at the switching position 45b.

Next, the branch switching passage 46a at the switching position 45a is connected to one inclined surface 43 at a position where it can be connected to the first discharge port member 32.
In the surface 42 which opens in the middle and branches in the middle and comes into contact with the connecting member 20, the resin communicating passage 21 of the connecting member 20 is opened.
It is bored in a shape that communicates with both sides of 22.

On the other hand, the switching passage 46c branching from the switching position 45c opens at a position on the other inclined surface 44 where it can be coupled with the second discharge port member 33, and on the surface 42 that branches off from this point in the middle and comes into contact with the connecting member 20, the Similarly, the resin communication passage 21.
It is bored in a shape that communicates with both sides of 22.

Several bolt holes 48 for fixing to the connecting member 20 are bored on both sides of each of the aforementioned switching passages 46a, 46b, and 46c.

(Operation of the embodiment) The operation of this embodiment is the same as that of the present invention, but to explain it specifically, first, the connection member 20 and the discharge port member 34 are placed at the central switching position 45b of the switching member 40. ,3
5, loosen several groups of bolds 49 that fix the switching member 40 to the connecting member 20, and align the bold through holes 4.
8 and remove the second group of bolds (not shown) fixing each outlet member 34, 35 to the switching member 40, and separate the outlet members 34, 35 from the switching member 40, respectively.

Next, the handle 28 of the feed screw 27 is rotated to change the switching position 45b of the switching member 4o and the connecting member 20.
and the discharge port members 34, 35 are moved to the point where they coincide, and the switching member 40 is again fixed to the connecting member by the bold group 49, and then the corresponding discharge ports are placed in the counterbore portions of the switching passages 47b and 48b. After fitting the members 34 and 35, the discharge port members 34 and 35 are fixed to the switching member 4o by the second bold group.

In this way, when the two extruders 30 and 31 are operated, the two types of resin are separately supplied to the switching member 40.
The resin is supplied separately to the cylindrical resin passage 11.12 of the head die through the switching passages 47b and 48b of the resin member 20 of the connecting member 20, and further through the resin communication passage 21.22 of the resin member 20 of the connecting member 20, and is supplied to the cylindrical resin passage 11.12 of the annular discharge port 13 in front of the annular discharge port 13. The inner and outer layers merge and are extruded into a single parison.

At this time, in order to change the thickness ratio of the resin layer inside and outside the parison, the ratio of the extrusion amount of the extruder 30.31 can be changed, or the flow rate control valve 21a provided in each resin communication passage 21. , 21b are adjusted.

Next, in order to make the parison extruded from the annular discharge port 13 into a parison made only of resin from one of the extruders 30 and 31,
After stopping the operation of both extruders 30, 31, remove each discharge port member 34, 35 from the switching member 40, remove the switching member 40 from the connecting member 2o, and move the handle 28 in the same manner as the first movement procedure of the switching member 40. to rotate the feed screw support 27 to move the switching member 40 to the desired switching position 45a or 45.
C, the connecting member 20 and the discharge port member 34.
In addition, the switching member 40 is fitted with a discharge port member 34 that matches the purpose.
Or combine it with 35 to suppress the suppressor 3 only on the contacted side.
Resume operation of only 1 or 32.

In this way, if the resin on the side whose operation has been stopped, for example, the extruder 30, is stopped and only the extruder 31 is connected, that is, the switching position 45c is the connecting member 2o and the discharge port member 34, 35.
If the switching member 40 is moved to a position that matches the above and reconnected, the space between the resin communication passage 21 of the connecting member 20 and the cylindrical resin passage 11 of the head die 1o is filled with resin from the extruder 3o. , this is newly extruded by the resin of the other extruder 31 fed through the switching passage 46c with branch passages, and finally the cylindrical resin passage 11.12.
are both made of the same resin, and the parison extruded from the annular discharge port is made of a single resin.

Next, the switching member 40 is moved so that the switching position 45a on the opposite side matches the connecting member 2o and the outlet member 34.35, and the connecting member 20, the switching member 40, and the outlet member 3 are again moved.
4, the extruder 30 will now feed both cylindrical resin channels 11,12.

When these resins were being switched, the switching passages 46a, 46b, 46c of the switching member 4o and the extruder 30.
Each resin in No. 31 is left as it is, and the temperature of the extruder that is not used is lowered.

Effects specific to the embodiment In the embodiment, in addition to achieving the effects of the present invention, the surfaces of the switching member 4o where the extruders 30 and 31 are connected are set at 90° to each other.
Since the inclined surfaces 43 and 44 are different from each other, the two bending paths 57b and 48b constituting the central switching path 46b can be provided close to each other. The switching member 40 and the connecting member 20 and the switching member 40 and the discharge port member 34 and 35 have a structure in which they can be moved and fixed with bolts, and each switching passage 45
Since a, 45b, and 45c are completely separated from each other, there is no risk that the two resins will leak out after switching.

In addition, the structure is simple and does not cause trouble, and the switching time can be extremely short, and the resin in the switching member 4o and extruder 30 and 31 is not wasted at all, and the amount of resin discarded during switching is reduced by the connection. The amount of resin in the member 20 and the cylindrical resin passages 11 and/or 12 is kept to a minimum, thereby minimizing the increase in cost.

In the above-mentioned invention, one cylindrical resin passage 11.12 has two
We explained about the heavy one, but in the case of three layers, connect the connecting member 2.
Since the number of resin communication paths of 0 becomes three, the number of combinations of switching paths of the switching member 40 increases, and the length of the switching member 40 also increases, it is better to make it into a disk shape and rotate it to switch the resin. The invention can be made smaller and the invention remains the same even with this modification.

[Brief explanation of the drawing]

The drawings show typical embodiments of the present invention, in which FIG. 1 is a longitudinal cross-sectional side view of the extruder separated from the extruder, FIG. 2 is a plan view of FIG. 1, and FIG. 4-line cutting ratio surface diagram,
FIG. 5 is a longitudinal sectional side view of the switching member at one switching position, FIG. 6 is a longitudinal sectional side view of the switching member at the other switching position, and FIG. 7 is a longitudinal sectional plan view of the fixed portion of the switching member. Main symbols in the figure 10...head die, 11.12...cylindrical resin path, 14.15...
... Resin supply port, 2o ... Connection member, 21.22 ... Resin communication passage, 30.31 ...
...Extruder, 34.35...Discharge port member, 40...Switching member, 45a, 45b, 45c --Switching position. 46a, 46b, 46c -- switching passage.

Claims (1)

[Claims] (1) The parison head die is provided with at least two inner and outer cylindrical resin paths, which merge on the downstream side and are formed to communicate with a single annular discharge port, and each cylindrical resin The upstream ends of the passages are each independently connected to resin supply ports provided on the outer circumferential surface of the die, and resin communication passages that are independently continuous with these resin supply ports are arranged in parallel to form a single resin passage. The resin supply port of the die can be connected to the discharge port member of an independent extruder through a connecting member, and the upstream ends of the resin communication passages of the resin path connecting member are provided adjacent to each other. A single resin path switching member is provided between the upstream end of this resin path connecting member and the discharge port member of each extruder, and this resin path switching member has different branches or channels at each switching position. Switching passages each having a combination of communication passages are bored, and the switching member is provided at each of these switching positions so as to be movable and tightened with respect to the connecting member and the discharge port member of the extruder. resin switching device. 2) The shapes of the switching passages at each switching position are different from each other.
One of the switching positions is provided with a parallel switching resin path that connects each extruder discharge port and each resin communication passage of the resin connection member in parallel, and at least one other switching position is provided with a parallel switching resin path that connects each extruder discharge port and each resin communication path of the resin connection member in parallel. Block the outlet, branch from the switching resin connected to the discharge port of the extruder other than the blocked extruder, and form a branched resin path at a position communicating with the resin communication path corresponding to the blocked extruder. 2. The resin switching device according to claim 1, further comprising a branch switching resin path. 3) The resin path switching member is a bar-shaped member whose cross section has the same outline shape, each switching path is provided almost in a direction perpendicular to its length, and a screw is provided near each switching position to tighten with the resin path connecting member. 2. The resin switching device according to claim 1, wherein several screw holes are provided around each switching passage through which the through hole also connects with the discharge port member of each extruder. 4) The resin switching member is of a rotary type, and each switching passage is arranged concentrically around its rotation axis, and a screw hole for tightening with the resin connecting member is provided near each switching position. 3. The resin switching device according to claim 2, wherein several of these are provided.