Regular division of melt flow in extrusion of blown films

Description: TECHNICAL FIELD [Detailed description of the invention]

The flow of the melt when the blow-molded film is extruded How to divide regularly Field of invention The present invention is an extrusion-molded annular product, especially an extrusion-molded plastic resin. Products manufactured by the line, most specifically injection molded plastics Regarding improving the quality of the ilmu. Background of the invention When manufacturing such a cylindrical product, the raw material of the product is an annular extrusion die. It is extruded from and drawn along the axis of the die. Blow-molded file In the case of Lum, the plastic resin is from a heated extrusion molding machine with an annular die. The extruded and melted polymer is drawn along the die axis in the form of expanded bubbles. Be kicked out. After the resin cools to a predetermined diameter as a result of the application of cold air, bubbles Crushes and proceeds into the nip roll for further manufacturing steps. As the film is extruded, the thickness fluctuates along the circumference of the foam. This Like a printing press, laminator (laminator), or bag making machine, if there is a variation in the thickness of Problems for downstream conversion equipment Occurs. The film is not converted in-line, but once rolled before conversion In the case of going through a winding process, the process involves a large number of layers of film on the roll. When becomes, the thick region and the thin region of the film generate uneven parts on the roll surface. These uneven portions deform the film. These uneven parts are special In the case of a large-diameter roll, the problems associated with the subsequent conversion become remarkable. others Therefore, not only blow-molded films, but also other extruded cylindrical products. Similarly, it is desirable to minimize the variation in the thickness. For this purpose To achieve, manufacturers over time with these thick and thin areas Make the position random, or convert the finished roll to a subsequent conversion Designed to automatically reduce the degree of such fluctuations so that they are suitable for use. You are using expensive equipment. The variation in thickness is in the circumferential direction of the flow distribution passage (port and spiral part) in the die. Non-uniformity, non-uniform viscosity of the melt, and passing as the polymer exits the die Found to be due to various factors, such as non-uniformity of the annular die voids There is. The problem with the distribution of flows within the die is that they are typically "po". High spots and low spots, called "trine", arranged at relatively steep and narrow intervals Special interest because it takes the form of high and low spots It is a thing. Furthermore, the cold air fluctuates and the atmosphere surrounding the extrusion molding line. The non-uniformity of the air sucked into the flow of cold air from the film mainly causes the thickness of the film to fluctuate. It is the cause of sagging. Many film manufacturers have traditional blow-molded film equipment Is used to determine the thickness of the film. This method typically involves film The overall thickness is changed within a fluctuation range of ± 10 to 20% on average, and its greatest effect is the standard. The type is to vary the thickness of the port line. Improve the die to obtain higher quality film and other products The flow device can operate faster and longer, and the final product is more uniform. It is desirable to have a uniform thickness. One major difficulty that must be resolved when designing a die is "melt". Typically of molten polymer, or other material, carried to the die through a pipe. How to convert a non-uniform flow into a relatively thin annular flow. Circular flow That is not just a surrounding outer wall, such as the outlet of a melt pipe, It means that there are inner and outer molded walls. Flow of melt through this thin molded wall In order to introduce it into this, the outer wall of the die surrounds this newly formed wall. It is necessary to firmly fix it in the bitty. For this, the flow of melt material A flow in which a connecting structure is placed in the path and the connecting structure forms a number of separate flows. Temporarily disturb this, then allow the flow to pass through the connection structure and something Must be combined again in a way. Unfortunately, the molten polymer Primarily changes in properties at the molecular level, and local changes in polymer temperature Due to this, it exhibits a non-uniform viscosity of the melt. All of these effects on viscosity It is called rheology as a body. One of these properties, which is of primary concern, is The polymer exhibits "non-Newtonian" flow behavior. This is a polymer It means that the viscosity of the polymer changes depending on the speed at which the polymer flows through the predetermined passage. Taste To. The pure effect of the combined effects of all viscosities depends on the viscosity of the polymer. Tends to separate and can be uniformly recombined with a large number of polymer streams It will be extremely difficult. In addition, the molten polymer goes through the previous flow. Remembering the latitude, many polymer streams are seamlessly recombined. Rather, it forms an unwanted "weld line" and this "weld line" Then, the flows that are adjacent to each other will be combined again. Weld line The problem is also especially noticeable when the polymer deteriorates due to the low flow rate of the polymer. It becomes. Currently some to provide a connecting structure between the outer and inner molded walls of the die Method is adopted. One method is to use a small distribution chamber in the die with a central axis. It is supplied from the wire. This chamber separates the polymer and its polymer -Led into several thin pipes, called ports, which are evenly spaced. These ports expand radially at an angle to the flow axis of the inflowing melt. To. These ports have a diameter suitable for recombining into an annular flow. Carry the polymer in such a way that this annular stream exits the die. another The method is to form a mushroom-shaped distribution chamber, which exits the die, approximately axially. Relatively allowed to be recombined quickly before forming an annular stream of directions A small, extremely streamlined spider-like connection structure at an angle to the flow axis It is to extend radially from this mushroom-shaped distribution chamber. Furthermore Another method is to feed the die radially from the side of the die and also a stream similar to a tree branch. Divide the flow more than once through this network, and the branches are finally separate Carrying a stream of polymer and recombining it into an annular stream out of the die Make the diameter suitable for. Generally, one or more in the die of blow-molded film Flow separation method must be adopted, but each of the methods is a question associated with separation. It can create issues and form weld lines. Limit these effects In order to do so, special recombining techniques must be adopted. To recombining the flow of individual melt materials with the annular flow coming out of the die Several techniques are used in. Some of them form an onion-like stacking effect Designed to superimpose separate streams, while others are opposed streams The time, temperature and time for the recombination to be made by abutting them further upwards. It allows pressure to be possible. The most commercially available film in the manufacture of blow-molded films Common recombining techniques employ passages that form a spiral around the axis of the die. It is a thing. These so-called spirals overlap each other and the molten polymer It is gradually blown out of the passage over the "land part", and finally it is a layered re-layered onion. Flow towards the annular outlet of the die to form a combined flow. This ring Polymer flow out through the die outlet, commonly referred to as the die overhang To. The main problem with this method is the non-Newtonian flow caused by the polymer. Must be non-uniform so that it and other non-uniformities can be corrected There is no point. Unfortunately, in terms of the flow characteristics of the various polymeric materials being processed There are significant differences. For a given die design, a flow ring for one material It can be evenly distributed around, but not with other materials .. Instead, other materials are somewhat in position depending on the nature of the material being processed. , Tends to form sinusoidal high and low flow points. For this reason The spiral design method keeps the thickness variation at a constant foreseeable minimum while at the same time widening it. Its ability to process a range of materials will be limited. Another problem is that the polymer, or other material, inevitably flows through the aisle. It requires a long time, i.e. a long residence time, which degrades the material. It leads to. In addition, significant back pressure is created as the material flows through each passage. To. A distribution passage and a spiral portion extending substantially in the plane of the plate coaxial with the flow axis of the die. In the design of the including "pancake mold", the moist surface area is extremely large, which is why , When combined with higher pressure, the separating force generated in the adjacent plate is extremely large. Therefore, it becomes impossible to hold the dies together. For this reason The designer of B is forced to limit the degree of pressure, which is uniform. Distribution tends to be impaired. In addition, it is often lower by increasing the flow path. Pressure is obtained. However, this increases the dwell time, which in turn increases the po. Deteriorates the nature of the limmer. In reality, the effects of pressure and distribution must be balanced. Ba However, this limits the extent to which the die is made larger. The recombining method adopted as the next best measure does not overlap the flow, Instead of, the streams merge at one or more different locations. Facing At such a position where the two streams meet together, the flow rate is extremely low. Therefore, the residence time of the material becomes extremely long, and as a result, the polymer deteriorates. This Degraded polymer has poor optical properties and a separate weld that reduces strength It will form a line, which limits the use of those with such designs. To. On the other hand, since there is no overlapping part, the flow path is designed to overlap. It will be shorter. This allows for limited deterioration and larger designs. It has the advantages of low pressure and short residence time. Also, non-overlapping design In the one, the flow path is clearly defined and displaced around the flow path due to the overlapping design. Unlike the case, the polymer has the same geometric morphology regardless of the flow characteristics of the melt. Be urged through. Non-Newtonian flow through a given geometry is sufficient As understood, this simplifies die design. Inconvenient And when the flow characteristics of the melt are different from those used in the die design, at the time of distribution Non-uniformity still occurs. As a wider range of polymers can be selected Well, this is a bigger problem. For manufacturers, extruded materials, each of which has its own special properties The range of fee selection tends to expand more and more. For example, some polymers are water Resistant to vapors, others resist the permeation of oxygen, yet others have high strength , Or provides high drilling resistance. Increasingly, manufacturers are new to these materials. It has been adopted and is layered so that property advantages can be obtained in some fields. That is, different polymers can be combined together in a "coextruded" structure. I know what is desirable. For this reason, the die is designed with a large number of installation points. This, however, distributes the polymer stream into separate annular streams, which Later, while still in the die, do this so that one is inside the other Contributes to layering. Although a non-overlapping design is used, The most popular was either in concentric form or in pancake form. It is an overlapping design. The pancake design stacks individual layers on top of each other Miju It is suitable for a larger number of layers because it can be squeezed. Concentric design Is about 5 for the simple reason that the diameter of the die is too large to be practical. Limited to only 7 layers. Having multiple layers cancels out some of the thickness variations present within each layer. It has traditionally been recognized that it brings the secondary benefit of being able to To. This has one drawback. That is, the fluctuation of each layer is the flow of the related melt. Since it depends on the characteristics, production volume, temperature, etc., the fluctuation is typically not necessarily averaged. It is not done. In practice, the multiple layers are evenly aligned on top of each other Does not average the thickness at all. This is especially true for overlapping designs. It is that the melt is in position even if slight fluctuations occur within a given layer. And it fluctuates remarkably in terms of size. Attempt to achieve this averaging effect As a commercial co-extruded die, adjacent layers typically bend in opposite directions. Some are designed to have a shaped part. For concentric die designs, die flow axis Because it is not formed in a spiral shape at the same distance from the line. The spiral part for each layer is However, they differ in terms of design. Pancake designs are on the same machine Although it can be in a typical form, each layer is stacked on top of each other, so each layer Inevitably, the length of the path to the overhanging part of the die is different. This means that each layer Corrects differences in flow behavior as a result of acting at different pressures. With averaging effect Commercially available dies designed to be embodied will increase production over the entire process range. As a result, both very good and very bad fluctuations in overall thickness occur. Let me. This is because the variability of the layers formed first occurs in a facing (good) state and then each other. Occurs as a (bad) state consistent with. A further problem with these designs is the thickness. Individuals, even if the fluctuations are opposite and cause fluctuations in good condition overall The distribution of the layers can still be bad. This is especially true , Unfavorable effect when each layer is designed to take advantage of different film properties The layer that provides fruit and serves as a barrier to oxygen or water vapor separately is Even if the overall thickness is uniform, it can vary widely from one to another. individual A uniform distribution state for each of the layers and for a combination of multiple layers Revealing is highly desirable. Outline of the invention The present invention homogenizes the distribution of melt extruded material to each of the individual layers. Regular divisions (RD, re) that exhibit a high degree of insensitivity to the flow characteristics of the melt gular division) Die and pressure resistance type that does not limit the size of the die It features a distribution device. The design of this die is the extrusion of polymerization-based blow-molded films. Other forms of extrusion methods that are particularly applicable to slab molding but require an annular die. Also applies to. The extrusion molding line for blow-molded film is typically Melt the flow of plastic resin and pressurize the flow of melted plastic resin Heated extrusion molding machine for, and foam that extrudes and expands molten resin An annular die through which the resin passes when pulled out along the axis in the form of It is equipped with an air-cooling device having a structure that guides the contact to each other, and the cold air device is cold. The wind is allowed to flow along the bubbles, and the maximum constant is approximately constant at the freezing line separated from the annular die. Allow the molten resin to cool as the film expands until the foam diameter is achieved. To. The RD design is an integral part of one or more individual die layers within a complete die. Can be included. According to one preferred embodiment, of this RD design Can be integrated separately within each layer of pancake type stackable dies Wear. Each of the layers is a series of concentric liquors that perform the functions of supply, distribution and recombination. It has a ring with one inside the other. This These rings surround and contact each other on the surface and / or the polymer itself. The polymer travels between the rings unobstructed through a notched passage through the ring. And enable. These rings are both bolted together into a single unit Forming a layer, this layer is stacked to face the other layer of the complete die, each The geometric axis in the center of the layer is made concentric with the flow axis of the die. Polymer -Is supplied separately within the outer diameter of the supply ring on the outside of each layer. Polymer is supplied Proceed straight in the radial direction through the ring and the associated inward radial distribution phosphorus Reach For the following explanation, the position of the input part that penetrates the supply ring is 0 °. It shall be in the place. The distribution ring has a machined flow path on its radial outward facing surface. Therefore, this flow path functions to divide the flow at least once. On the outside (or with this) Alternatively, cut the passage (on the side facing inward in the radial direction, or on both sides). With and, the detrimental effect of the separating force due to the pressure of the polymer is eliminated. To polymer The more generated force is not the bolts that hold the layers together, but the surrounding supply ring Acts on. In the distribution ring, the polymer flow inputs from the supply ring are equal in number (2).ⁿ) Is divided into independent and equal flows. In a preferred embodiment, the input flow Has 8 flows (2) in 3 stages³) Is divided. The first division of the flow is 0 ° At this point, the polymer flow is split in two and half of that flow. Each of the two passages is introduced into one of the two passages, each of which flows around the circumference of the ring. Make one clockwise turn from 0 ° to 90 ° and bend 90 °, the other of which is 0 ° Rotates counterclockwise from to 270 °. Each flow (maximum) at 90 ° and 270 ° Half of the first flow) rotates and axially a short distance before the second split It flows. This second split is done separately at the 90 ° and 270 ° points. Each of them At the point, the flow is again split in half and the part of the flow formed (1 of all input flows). / 4 parts) are around the outside of the ring in opposite directions from the 90 ° and 270 ° points, respectively. Guided to one of a pair of passages that turn 45 °. These four streams are 45 ° and 135 ° , 225 ° and 315 °, and at these points the flow is divided again. In this case, it is divided into opposite bending angles of 22.5 °. The final of these three divisions As a result, it became 22.5 °, 67.5 °, 112.5 °, ..., 337.5 ° at intervals of 45 °, respectively. There are eight separate streams that end in the end. After each split, each of the opposite bending angles The lengths of the pathways are equal and therefore do not occur in all passages through which the polymer flows. Ensure that the pressure drops are equal. These eight divided streams then pass through the first distribution ring in the radial direction. Flowing inward and reaching the recombined ring directly or further division is desired If so, the second distribution ring is reached. To use one or more distribution rings More, it is possible to achieve a larger number of "n" divisions without reducing pressure You will understand that you can. In either case, the desired number of divisions is the distribution ring After being done within, the flow formed is the final (ie, innermost radial) distribution. Within the radial direction to the recombined ring through the split plate that forms the integral part of the ring It is carried to the direction. The split plate is compared to the main body of the distribution ring of which the split plate is a part (of the die). Relatively thin (when measured in the axial direction). This split plate is 2ⁿForm a polymer stream And the final radial inward, tapered to a thin edge on its inner circumference It extends inward from the part of the distribution ring of. In the dividing plate and as a whole Before the par is attached, 2ⁿRadial flow alternates on one side of the plate, or Directed to the other side of. This is separate, but two identical flow patterns Each of its flow patterns is placed on either the top surface or the bottom surface of the split plate. Out of the port, 2 (^n-1) Recombined flow is included. Meanwhile, these The flow is supplied to a pair of recombined plates that abut on the top and bottom surfaces of the split plate. One recombined plate is attached to one side of the tapered portion of the split plate There is. The recombined flow port formed on one side of the split plate is on the opposite side of the split plate. It is staggered so that its center is between the ports of the part. this thing Is that an accurate mirror image recombination occurs, that is, "minutes" at both sides of the split plate. Allows "flow" to be done. Such a divided, mirror image-like flow is divided. They meet together at the inner edge of the board. The flow of this recombined flow on each side of the split plate Flow distribution that gives a flat flow profile when the path is added to its mirror image form Form a state. The non-sensitivity of the melt to rheology is when the recombined streams are non-overlapping. Allowed to be distributed, which forms a foreseeable non-displaceable polymer flow. It is achieved by making it possible. Place the intervening land area directly in front of each port By placing it so that the main flow path passes through the diameter part behind the land part, The formation of rudlines is avoided. Thus, a portion of the flow from each port It flows above the land, and half of the rest goes down in one direction along the aisle. Flow, the other half flows in the direction of that half body. Finally from one port The flow of the aisle merges with the flow in the opposite direction from the adjacent port. At this point The main flow path travels inward in the radial direction between the ends of the adjacent land portions. this child Form one weld region, which is a high flow region Therefore, the problem of polymer deterioration is substantially eliminated. Next, the main passage is , Divide again and proceed through the diameter section in front of each of the associated land sections. Therefore, half of the flow flows downward in one direction along the passage, and the other half flows in the opposite direction. It flows in the opposite direction. Thus, first deflected around the land section through the main passage. The flow that has been made is recombined with the flow of the land section. This aspect is foreseeable It is stable, but gives a layered effect. In this respect, the one with a spiral design Is similar to. However, the position does not change. This is circular and within the radial direction The recombined flow directed towards the top of the final land section of the split plate It reaches the top, and at the top of this split plate, it is divided into mirror images coming from the opposite side of the split plate. Flow is added. Less flow where high flow weld lines occur To ensure that the center is in the land area where the higher flow rate intervenes. The final passage and land section are cut in by the way. That Adding a mirror image stream adds a larger flow (non-welded) area of the mirror image. This minimizes the harmful effects of weld lines. Flow to ensure uniform combined flow from both sides of the split plate Flow out of the recombined area on each side of the split plate before recombining Their shape is important. For certain materials, the individual flow from each half is uniform You can, but the flow is not necessarily what you have to do I. Various songs that, after addition, produce a uniformly flat combination profile Wires can be incorporated into the flow path design. Used for crystallographic research, or MC As you can see in the representation of the figure by, "regular de "Visions of the plane)" can be examined mathematically. Escher Shows suitable examples of both simple profiles and complex profiles. each One suitable profile for split flow is in high flow weld lines. A straight "triangle" that linearly increases from the minimum flow rate to the maximum flow rate in line with the port It is a profile. This profile does not discontinue around the layer, it It repeats itself. The second preferred split flow profile is similarly high flow. A "sine" that has its minimum value in the quantity welding line and has a maximum value that is in line with the port. Wavy "profile. A brief description of the drawing FIG. 1 shows a blow-molded fill with a multi-layered regular split die according to the present invention. It is a schematic side view which shows the extrusion molding apparatus of a mu. FIG. 2 shows the regular split dies for extrusion molding of the blow-molded film of FIG. It is a schematic side sectional view (along line AA of FIG. 3) at an enlarged scale. Figure 3 shows the overall multi-layer blow-molded film relative to the extrusion die. It is a plan view of the arrangement. Figure 4 shows the overall supply inlet, split aisle, recombined port, and aisle. Partial side profile of one layer with respect to a regular split die showing position (Figure 4a) Along the line BB). Figure 4a shows the overall supply inlet, split aisle, recombined port, and aisle. It is a plan view of one layer of the regular split die of FIG. Figure 4b shows the supply inlet on the outer surface of the layer and the split passage when viewed inward in the radial direction. Regular minutes in Figure 1, showing the overall location of roads, recombined ports, and passageways. It is a schematic diagram in which the center is in the hole of the supply inlet of one layer of the split die. Figure 5 shows the upward reassembly when viewed upward from the top surface of the tapered portion of the distribution plate. It is the schematic of the mating passage and the associated land area. FIG. 5a is paired with FIG. 5 when viewed downward from the lower surface of the tapered portion of the dividing plate. It is a schematic view of the lower recombined passage and the land portion area arranged in the above. 6 and 6a are typically desired from the upper and lower recombined rings. It is sectional drawing which is the schematic of the flow part. Description of preferred embodiments In Figure 1, the molten plastic resin can form a blow-molded film. An extrusion molding apparatus for a blow-molded film extruded as described above is illustrated. .. Except for the die 10, the device of FIG. 1 and its operation are the same as before. one Generally, the plastic pellets are fed into the feed hopper 2a and are an extrusion molding machine. Carried into 4a, the plastic pellets are extruded in the extrusion molding machine. It is melted, mixed and pressurized by the action of the screw of the molding machine. The melt is Out of the extruder 4a and carried through the melt pipe 6a, the melt pipe The melt is introduced into the die 10 of the blow-molded film. Die 10 Melting Designed to form the melt in the flow 14 of the annular cylindrical plastic melt Then the flow of the melt is an annular orifice die at the top of die 10. It is extruded from the overhanging portion 16. The flow of this annular melt as a whole Continuously drawn from the annular die overhang 16 in a state concentric with the center line 18 of the process. It has been squeezed out. The flow of the melt reaches the freezing line 20 (shown graphically with the saw tooth line). From the die until it forms a cooled, solidified plastic tubular film foam 22 As it advances, the annular diameter of the melt increases in size. The main cold air for the process is the outer air ring from the conventional air source (not shown) 2 Supplied to 4. This air is brought to the base of the foam by the overhanging part 26 of the air ring. It is supplied so as to be in contact with a melt of plastic that is adjacently extruded. This air flows in an annular air stream 28 along the expanding outer surface of the foam. some Other forms of cooling are also employed in the blow-molded film process. One such device (not shown) supplies cold air to the inner surface of the foam according to known techniques. , Commonly referred to as the internal foam cooling method, or simply "IBC". plastic The melt is sufficiently cooled by the freezing line 20 to solidify into the tubular foam 22. Further, according to a known technique, the tubular foam 22 is a folding frame 150, 150. It is continuously sucked upwards through a, and at this folding frame, the tubular foam is When passing through the nip point between nip rolls 152, 152a, "Ray Hula" On sheet 22a of flat film, also known as "lay flat" It is compressed. These nip rolls continuously extrude the film from the molding process. Driven to pull. Next, the ray flat film sheet 22a is rolled. It is wound into a finished product by a downstream processing device such as the scraper 156. Figure 2 shows a regular split type with multiple die layers 30a, 30b, 30c. Schematic side sectional view of the extrusion die 10 of the blow-molded film is shown. It has been. Die layers 30a, 30b and 30c are approximately identical and are illustrated in Figure 3. Rotated relative to each other. Each of the layers melts from their respective melt pipe 6 The supply of the melt is converted to form a flow 14 of the cylindrical plastic melt, which The flow of the melt is around the cylindrical inner mandrel 12 to the die overhang 16. Will be carried towards. Thus, the layer 30a is the flow of the melt from the melt pipe 6a. Is converted into a melt flow 14a, and layer 30b is a second cylindrical plastic melt. Forming body flow 14b, the flow of the melt is a cylindrical plastic melt Luck around the flow 14a and inner mandrel 12 towards the die overhang 16 Burr, layer 30c is a cylindrical plastic melt flow 14b, 14a and inside A third cylindrical shape carried around the mandrel 12 towards the die overhang 16. Form a flow of plastic melt 14c. These three cylindrical pluses Tick melt flows 14a, 14b, 14c form adjacent layers, which Formed a flow 14 of the entire cylindrical plastic melt, which flow , Inner mandrel 12 and outer mandrel until exiting through the annular die overhang 16 It flows between Rel 15. Layer 30a has a large number of bolts 34a at the base of the die 1 It is held at 1. Layer 30b is placed on top of layer 30a by a number of bolts 34b. Stacked and held in layer 30a. Layer 30c has a large number of bolts 34c Stacked on top of layer 30b and held in layer 30b. Stack At the top of the body the outer mandrel 15 is at the top of layer 30c with numerous bolts 34d Stacked on and held in layer 30c. Seal area with an annular O-ring 3 Seal 2, 32a, 32b, 32c, die base 11 and layers 30a, 30b , 30c and each flat shaft formed by the overhang 15 of the mandrel Prevents the plastic melt from flowing outwards between the directional contact surfaces. In FIG. 3, a large number of layers as shown by reference numerals 30a, 30b, and 30c in FIG. 2 are shown. A typical blow-molded film extrusion die with a regular split mold 10 The overall arrangement of is illustrated in plan view. As illustrated in FIG. 3, layer 30a , Is supplied from the extrusion molding machine 4a by the melt pipe 6a. Layer 30b and related The attached extrusion molding machine 4b as well as the melt pipe 6b are associated with layer 30a, It is placed at an angle with respect to the extruded machine 4a and the melt pipe 6a. It has been. Similarly, layer 30c, associated extruder 4c and melt pie. The pump 6c is on the layer 30b, the associated extrusion molding machine 4b and the melt pipe 6b. It is placed at an angle with respect to it. Adjacent extrusion molding machine and melt pipe This angle is, for example, large enough to provide a gap between and Selected at approximately 60 °. The annular die overhang 16 is the outer surface of the inner mandrel 12. When, Formed by the inner surface of the outer mandrel 15. Many bolts 34d are on the outside It is arranged so that the render can be held in place. Many illustrated in Figure 2 Bolt 34b is directly behind a number of bolts 34d. Also, a large number of bolts 34a , 34c, one of which is above each other and each other, as illustrated in FIG. Arranged between a large number of bolts 34b and 34d stacked so as not to interfere ing. As shown in FIGS. 2 and 3, an arbitrary number of layers are stacked and in predetermined positions. The layer can be easily accepted in this way by bolting to .. FIG. 4 is an enlarged cross-sectional view of a portion of the die 10 of FIG. 1 having layer 30a, FIG. a is a plan view. Layer 30a is a series of concentric rings, one inside the other Consists of (supply ring 40, distribution ring 42 and recombined rings 45, 46) These concentric rings provide, distribute, and distribute molten extrusion material. And then it works to recombinate. In the illustrated embodiment, plastic The stick and polymer flow flows radially through the supply passage 50 and distributes. Reach the outer diameter of ring 42. As most clearly illustrated in FIGS. 4 and 4a, the supply ring 40 is annular and Approximately vertical plane to which the melt pipe 6a is attached and the radius of the annular distribution ring 42 A supply channel that extends radially through the stepped inner surface that engages with the facing outer surface. Has a road. On the other hand, each of the distribution rings 42 is approximately vertical (but slightly inclined) and half. Forming a series of annular stepped portions 42a, 42b, 42c with radially oriented walls The outer surface facing the radial direction is defined, and the annular stepped portion is in this embodiment. Annulus that is flat and parallel to each other (and perpendicular to the axes of the die and layer) Separated by faces. Lower and intermediate filament walls of the top maximum diameter wall portion 42a The underside of the minute 42b is the corresponding surface formed on the radial inner diameter of the supply ring 40. Seal against. O-rings 43a, 43b provide a seal on the contact surface, The Lut 44 (see Figure 2) holds both the distribution ring and the supply ring tightly together. The distribution ring 42 has an annular split plate portion 42d on its inner side. The split plate portion has its center at the overall height of the split ring, but at its own height. Is a vertical height within approximately 20% of the total height of the distribution ring 42 (distribution ring and die). (Value measured along the axis of). Illustrated, as most clearly illustrated in Figure 4. In the above-described embodiment, the top surface and the bottom surface of the dividing plate portion 42d are formed on the dividing plate portion. Flat over most of the radial width and parallel to each other, but split plates Adjacent to the inner edge of the portion, it is tapered towards each other. The recombined rings 45 and 46 are located above the top and bottom of the split plate portion 42d. Yes, both are bolted by bolts 34. Adjacent to its radial inner edge Then, the recombined ring extends inward in the radial direction of the radial inner edge of the dividing plate portion. It is long, close to each other, and ends near the outer surface of the inner mandrel 12. The main action of the distribution ring 42 is to create a large number of single streams from the supply ring 50 (immediately). Chi, 2², In a preferred embodiment 2³That is, divide into the same flow part of 8) To. To achieve this, a series of flow split passages 52, 54, 58 are stepped portions 42. It is machined on the outer surface facing the radial direction, which is almost vertical to b. Divided passage (passage 52 , 54, 58 are shown in the illustrated embodiment) , Limited only by the vertical dimension of the outer diameter of the distribution ring 42. Flow split passage 52, 54, 58 separate eight separate melts from supply aisle 50 of supply ring 40 Divide into the radial port flow 59 of. Most flows are supply ring 40 and The distribution ring 42 and the supply are located between the radial surfaces of the distribution ring 42. Forces 41a, 4 along the die axis that tend to move the ring 40 away It will be clear that 1b is relatively small. The reason is that their power is a seal Because it acts only on the protruding area (as seen in the plan view) between 43a and 43b. is there. The arrangement of the split passages is most clearly illustrated in Figure 4b, which is shown in Figure 4b. Schematic exhibition illustrating the radial outward facing surface of the wall portion 42b of the split ring 42 It is an open view (that is, a non-enclosed view). As shown, in the split passages 52, 54, 58 All extend circumferentially around the outward facing surface of the split ring and are the axes of the die. It is located approximately perpendicular to the line. The flow from the inlet supply passage 50 goes downward ( A short passage that is parallel to the axis of the die and extends approximately perpendicular to the split passage 52. It reaches the center of the split passage (via 51). Passage 52 is a distribution ring 42 A total of 180 ° turns around the outside of the aisle, and the flow from the entrance 50 is introduced into the aisle 52. Bend 90 ° in the opposite direction from the point where the melt flows from the inlet 50 in the opposite direction. Separate into two facing streams. At each end of the passage 52, the short vertical passage 53 The flow in each half of the passage 52 (in the axial direction of the die layer) of each of the passages 54 Introduce in one center. Each of the split passages 54 is around the outside of the distribution ring 42. Total 90 ° (each from where the flow from passage 53 is introduced into each passage 54 Bend in the direction (45 ° angle) and divide the flow of melt from passage 52 into a total of four flows To do. At each end of each of the split passages 54, each of the respective flow sections is again Directed vertically for a short distance through the short passage 55, each of the split passages 58 Reach one center. Each of the split passages 58 is 45 ° around the outside of the distribution ring ( Opposite direction from where the flow from passage 55 is introduced into each split passage 58 Bend to 22.5 °) and again, in this case, flow so that there are a total of eight equal flow parts. Divide it. At each end of each distribution passage, each flow section has eight radii Introduced in one of the directional passages 57, 59, the radial passage distributes its flow portion. Dividing plate portion of the distribution ring through ring 42 (as illustrated in FIGS. 2 and 4) On the upper surface of the passage (in the case of passages 59a, b, c, d) or on the lower surface thereof (passage 59a', In the case of b', c', d'), carry it in the radial direction. Radius as shown Each of the direction passages 59'is just outside the tapered part of the dividing plate part in the radial direction. At the position, each surface of the split plate portion 42d from each one of the split passages 58 Extends inward in the radial direction. The flow of polymer melt from the split passage 58 is Divided equally into the top and bottom of the split plate, half of which are upper ports 56a, 5 Head towards 6b, 56c, 56d, the other half down ports 57a, 57b, 57 Head to c, 57d. All of the flow paths 50, 52, 54, 58, 59 of the distribution plate 42 are symmetrical. Therefore, the length of the path that the melt must flow to reach each port is It will be appreciated that equality and even distribution are guaranteed. In the recombined ring 46, the upper port 5 on the top surface of the split plate 42d 6a, 56b, 56c, 56d are the recombined rings 4 on the top and top of the split plate. Evenly distributes its associated melt flow to four equidistant positions between 6 and To do. At ring 45, the lower ports 57a, 57b, 57c, 57d are minutes. Melted at four equidistant positions between the lower part of the split plate and the lower recombined ring 45 Distribute the flow of the melt evenly. The position of the upper part of the dividing plate is the lower part of the dividing plate. It is in the middle between the above positions in. A pair of radially spaced circular circles, as most clearly illustrated in FIGS. 4 and 5. Passages 60 and 64 are cut into the underside of the recombined plate 46 and are separated in the radial direction. Only a pair of similar circular passages 70, 74 cut into the top surface of the recombined plate 45 It is rare. A plurality of arc-shaped recombined land portions 62 are located between passages 60 and 64. It is formed on the lower surface of the recombining plate 46, and a plurality of similar arc-shaped recombinations A set land portion 72 is formed on the upper surface of the recombined plate 45 between the passages 70 and 74. ing. The final lands 66, 76 are the split plates of the passage 64 and the distribution ring 42. It is formed on the lower surface of the recombined plate 46 with the inner edge in the radial direction, and also passes through. Formed on the upper surface of the recombined plate 45 between the road 74 and the radial inner edge of the split plate ing. In this embodiment, each of the arcuate lands is slightly greater than 90 °. Set boundaries for small areas. Generally, the melt is from the radial passage 59 through the port 56 to the passage 60, or , Flows through port 57 to any of passage 70. Outer loop of recombined ring From roads 60 and 70, the melt is on the recombined lands 62 and 72, respectively. Recombined passages across or between adjacent ends of the land portion Flow inward through 61, 71 and reach inner recombined passages 64, 74 .. The upper melt is then placed inside between the final land portion 66 and the split plate 42d. It flows out from the recombined passage 64. On the other hand, the lower melt is the final run Flow out from the inner recombined passage 74 between the do part 76 and the split plate 42d To. Recombined seals 47 and 49 have recombined passages 60, with the melt on the outside. Prevent each from leaking to the outside from 70. These upper and lower melts Flows merge at the inner tip of the split plate 42d to form a combined flow 68, This combination flow 68 is carried inward to the outer wall of the inner mandrel 12, and this The inner mandrel forms a flow 14a of cylindrical plastic melt. In the illustrated embodiment, the recombined passage, the recombined land portion, and And the final land part is cut into the surface of the recombined rings 45 and 46. , Further, the upper surface and the lower surface of the dividing plate 42d of the distribution ring 42 facing each other are substantially flat. To. In other embodiments, some or all of these are cut into the split plate. be able to. The recombined passage and the land portion are arranged on the lower surface of the upper recombined ring 46. This is most clearly illustrated in Figure 5. This Figure 5 shows Po Schematic simple plan view of the recombined region, symmetrical around G56a Is. The flow enters the outer recombined passage 60 via the upper port 56a. .. As illustrated in Figure 4a, one half body is re-outer towards the upper port 56d. It flows downward along the combination passage 60 in a clockwise direction, and the other half is in the upper position. It flows counterclockwise toward To 56b. The melt is downward along the passage (ie, When flowing in the opposite direction (in the circumferential direction of the die), some of the polymer melt is recombined. It flows inward in the radial direction across the land portion 62a and reaches the inner passage 64. remaining The melt of the recombined land part 62a (its center at port 56a, 90 Passage 60 until you reach both ends of the (bounded by an arc slightly less than °) It flows in the circumferential direction, and at both ends of this recombined land, the melt is on top. Similar, but with opposite melt flow, resulting from port 56d, 56b Shed. In this case, the opposing streams merge or "weld" to a high flow rate. Weld lines 80a and 80b are formed, respectively. These merged flows Radial recombined passages 61a and 61b at both ends of the land portion 62a It rotates through and flows inward into the inner recombined passage 64. In the inner recombined land portion 64, the melt is the final land portion 66. Radially inward and downward along the recombined passage 64 inside It flows in both opposite directions. Downward along the inner recombined passage 64 The flow is layered at the top of the flow across the recombined land portion 62a. Also, it flows inward in the radial direction across the final land part 66. Final run The profile (ie, shape) of the radial inward flow of the portion 66 is mainly based on Depending on the design of the final land section, this final land section will be described below. Thus, variable length and / or also so that the desired melt flow profile can be set. Can be designed to include voids. FIG. 5a is the same as FIG. 5, but FIG. 5a shows the lower surface of the dividing plate portion as seen from above. Recombined in the downward recombined area between and the downward recombined ring 45 It differs in that it indicates the state in which the set passage and the land portion are arranged. Downward recombining The flow to the region comes from port 57, but in Figure 5a, to the upper combination region. A symmetrical arrangement is shown around the upper port 56a, which is why the upper assembly is shown. The relationship between the mating area (Fig. 5) and the downward recombining area (Fig. 5a) is the easiest to understand. To be understood. In the lower recombined region, the flow is lower ports 57d, 57a (shown). In addition, the outer reassembly is performed through the lower ports 57b, 57c) (not shown in Fig. 5a). Enter the passage 70. From each port as in the upper recombined area The flow flows downward along the outer recombined passage and is one of the flows from each port. The other half flows clockwise and the other half flows counterclockwise. Regarding Figure 5 As explained in the above, a part of the flow in the passage 70 is the recombined land part 72d, A melt that flows inward in the radial direction over one side of 72a and remains at the end of the land. Flows weld together to form a high flow weld line 90a and also half Inward through the radial recombined passage 71a to the inside of the inner recombined passage 74 It flows. In the inner recombined passage, the melt crosses the final land portion 76. Flows inward in the radial direction and downwards along the inner recombined passage 74 In the inner recombined passage, the melt is recombined. It is layered below the flow that crosses the lands 72d and 72a. Downward reassembly As in the mating region, the final land portion 76 is the desired melt flow. Designed to have variable lengths and / or voids so that files can be set To. The recombined land portion 62 and the passage 61 of the land portion of the upper recombined area Is 45 ° offset from the land portion 72 and the passage 71 in the downward recombining area. It will be understood that it is in the place. This arrangement is high from one recombined ring Align the fusion line of flow with the port from the opposing recombined ring in the radial direction Deploy. 6 and 6a show regular divisions, ie, upper and lower recombined areas. The flow profiles of the two suitable melts exhibiting the cross-sectional area of the flow from the region are identical. Yes, it is shown that they fit together without interposing a gap. High flow rate fusion wire 80a , 80b (also 80c, 80d) are produced in the low flow region of the final land part 66. Jerking. High flow fusion line 90a (also 90b, 90c, 90d) is the final run It occurs in the low flow rate region of the unit 76. The flow of the upper and lower melts is the split plate 42d When merging at the inner tip of the to form a combined flow 68, the opposing recombinations The final land area of the high flow rate of the set ring is added, and the effect of the fusion line is washed away. .. Flow profiles 82a, 82b (82c), 82d, 92a (92b, 92) c), 92d of these by choosing to be able to divide the shape regularly All flow profiles are locked together to create a uniformly distributed combined flow 68 Form. The present invention has been described with respect to specific structural embodiments, but is described in the claims. Various modifications to the above-described embodiments without departing from the spirit and scope of the present invention. It will be understood that it is possible to embody.