CN216068591U - Center feeding multilayer co-extrusion die head structure - Google Patents

Abstract

The utility model relates to a center feeding multilayer co-extrusion die head structure. The method comprises the following steps: the central shunting core is formed by superposing at least a plurality of shunting blocks, a plurality of central shunting holes are formed in the shunting blocks, and the central shunting holes are communicated with the corresponding feed inlets of the shunting blocks; the spiral body is provided with a plurality of groups of spiral runners, and each group of spiral runners comprises a main spiral runner communicated with the central diversion hole and a plurality of spiral branch runners connected with the main spiral runner; and the mold outlet comprises an annular flow channel, and the spiral branch flow channels arranged on the spiral bodies are converged in the annular flow channel. Therefore, the utility model improves the stability, the layer thickness uniformity and the overall film thickness uniformity of the film bubble during extrusion molding.

Description

Center feeding multilayer co-extrusion die head structure

Technical Field

The utility model is applied to plastic extrusion blown film equipment, in particular to a multilayer co-extrusion inner cooling die head with conical surface sealing, central feeding, central flow dividing and feeding on the same plane.

Background

The five-layer coextrusion head feeding mode in the prior art mainly comprises a center feeding mode and a side feeding mode.

Most of the current center feeding modes adopt concentric circle type core sleeves for layered feeding, the center lines of five layers of feeding holes are not on the same horizontal plane, the height difference ratio of the five layers of feeding holes is large, and the central heights of extruders in all layers are required to be different. Such a feed increases the length of the individual layer runners, the inventory of polymer in the die is high, and the overall height of the die is high. This would result in: 1. the operation is difficult when the film is drawn; 2. The possibility of decomposition of the polymer in the die during production increases; 3. the time required for replacing the resin or the color is long; 4. the relative distance between the die head outlet and the central line of the main traction is short, namely the effective height of the upper traction is reduced, and the cooling efficiency is reduced; 5. the different heights of the centers of the extruders further increase the manufacturing difficulty of the extruders.

The five-layer co-extrusion die head has the advantages that the corresponding processing and manufacturing difficulty is obviously increased due to the increase of the number of layers, and a side feeding mode with smaller processing and manufacturing difficulty is mostly adopted. The existing side-feeding five-layer co-extrusion die head has the advantages that a melt directly enters the cylindrical surface of each layer of flow channel, and is divided into two, four, eight or sixteen, and then the spiral flow channel is formed, so that the following problems can be caused: 1. the flow channel is too long, so that the sealing surface of the cylindrical surface is relatively long, the sealing is difficult, the number of the spiral flow channels is only eight (or sixteen), the spiral flow channels cannot be divided into 10 or 12, and the flow channels cannot obtain proper spiral lead angles on the cylindrical surface of the layer; 2. The lengths of eight (or sixteen) runners and the pressure drop of the melt cannot be completely consistent, so that the pressure and the temperature of the spiral diversion starting points of the last eight (or sixteen) runners are difficult to ensure to be consistent, the diversion in the circumferential direction is not uniform, and the uniformity of the layer thickness is reduced; 3. the side feeding mode causes the uneven distribution of the temperature, flow rate and pressure of the melt along the circumference when the spiral flow channel shunts, the unevenness can change along with the change of the extrusion speed and temperature of the extruder, the thickness of the film bubble and the film also changes along with the change of the extrusion speed of the extruder, the thickness of the bubble shape and the film needs to be adjusted frequently in production, the difficulty of production operation is increased, and unqualified products are easy to generate; 4. the non-uniformity of layer thickness makes the side-feed die extremely prone to increased production costs in the production of black and white films or barrier films, resulting in rejects.

SUMMERY OF THE UTILITY MODEL

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

The utility model mainly aims to solve the technical problems in the prior art and provides a center-feeding multilayer co-extrusion die head structure. The structure adopts central feeding and central shunting, so that the shunting pressure, temperature and flow velocity of each layer of melt along the circumference of a spiral flow channel are more uniform, and the stability, the thickness uniformity and the integral thickness uniformity of a film bubble during extrusion molding are improved; the flow channel distribution length is short, resin replacement or color is quicker, and polymer decomposition is reduced; the die head has a low profile, the effective height of upper traction is increased, the operation is more convenient, and the cooling effect is better; the conical surface sealing is adopted in the stacked conical central shunt core structure, so that the sealing reliability is improved, the assembly and disassembly are convenient and easy, and the phenomenon that the assembly and disassembly are damaged by pulling on the matching surface is avoided.

In order to solve the problems, the scheme of the utility model is as follows:

a center-feed multilayer co-extrusion die head structure, comprising:

the central shunting core is formed by superposing at least a plurality of shunting blocks, a plurality of central shunting holes are formed in the shunting blocks, and the central shunting holes are communicated with the corresponding feed inlets of the shunting blocks;

the spiral body is provided with a plurality of groups of spiral runners, and each group of spiral runners comprises a main spiral runner communicated with the central diversion hole and a plurality of spiral branch runners connected with the main spiral runner;

and the mold outlet comprises an annular flow channel, and the spiral branch flow channels arranged on the spiral bodies are converged in the annular flow channel.

Preferably, in the above center-fed multilayer co-extrusion die head structure, the feed inlets corresponding to the shunting blocks of each layer are located on the same plane and are distributed at equal intervals along the circumference.

Preferably, in the above center-feed multilayer co-extrusion die head structure, the number of the flow dividing blocks and the number of the spiral bodies are 5.

Preferably, in the above center-fed multilayer co-extrusion die head structure, the feed inlets corresponding to the respective shunting blocks are communicated with the central shunting hole at the centers of the shunting blocks.

Preferably, in the above center-fed multilayer co-extrusion die head structure, the cross section of the center flow-dividing core is of an isosceles trapezoid structure.

Preferably, in the above center-feed multilayer co-extrusion die head structure, the shunt core is tightly connected with the inner layer spiral body through a screw, and a conical surface seal is arranged between the shunt core and the inner layer spiral body.

Preferably, in the above-mentioned structure of the center-feed multilayer co-extrusion die, the outlet includes: adjusting ring, neck mold plug-in;

the neck ring is positioned in the adjusting ring, an annular flow channel is formed between the neck ring and the adjusting ring, and the annular flow channel is communicated with the spiral branch flow channels arranged on the spiral bodies;

the die insert is positioned on the die through the cylindrical surface and is in compression connection through the screws.

Therefore, compared with the prior art, the utility model has the advantages that: 1. the height of the die head is reduced, the length of a flow passage is shortened, the cooling efficiency is improved, the operation of film pulling is more convenient, the polymer storage in the die head is reduced, and the material changing or color changing is quicker. 2. The central feeding center of each layer of the shunting core is in shunting characteristics, so that the number of spiral runners is not limited to 8 or 8 multiples any more, the design of spiral runner lift angle and the like is more convenient, before spiral shunting, a one-to-two structure of 8 central shunting runners which are uniformly distributed on the circumference enables the material flow temperature, speed and pressure distribution of each layer of melt to be homogenized again, the thickness uniformity and the integral thickness of the film are improved, the optimal distribution uniformity is obtained when a five-layer co-extrusion die head processes a barrier film and a colored film, and the production cost is reduced. 3. The conical surface sealing is adopted between the conical shunt core and the inner layer spiral body, so that the conical shunt core is convenient to assemble and disassemble while the optimal sealing effect is achieved, and the phenomenon that the matching surface is easily scratched when the conical shunt core is assembled and disassembled in a large-area matching mode is avoided. Secondly, the utility model adopts the plug-in structure on the design of the neck ring, can conveniently change the neck ring plug-in according to the production requirement of the film product to change the gap of the neck ring, reduces the difficulty and time of neck ring replacement, solves the problem that the downtime can not be overlong in the production of the barrier film, and is more beneficial to the production of the barrier film and various functional films.

Drawings

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the utility model and to enable a person skilled in the pertinent art to make and use the disclosure.

FIG. 1 illustrates a schematic view of a co-extrusion die configuration in an embodiment of the present invention;

fig. 2 illustrates a schematic diagram of a flow dividing channel with a central uniform distribution in an embodiment of the utility model;

embodiments of the present invention will be described with reference to the accompanying drawings.

Detailed Description

Examples

This embodiment adopts the design of stack form circular cone type center reposition of redundant personnel core, the feed inlet with five layers of crowded die heads is directly set up on the coplanar, each layer fuse-element all enters into the reposition of redundant personnel core central line of die head back, the 14 center reposition of redundant personnel holes of diameter of 8 (also can divide into 9 as required, 10 etc.) partitions again, after the face of cylinder of entering each layer, in order to improve the temperature distribution homogeneity of fuse-element, carry out the distribution of one minute two, divide into 16 runners with 8 14 runners, carry out the reposition of redundant personnel of spiral runner again.

This example will be exemplified by a five-layer coextrusion die, but those skilled in the art will appreciate that the application of this approach is not limited to a five-layer structure.

The present embodiment will be further described with reference to the accompanying drawings.

Referring to FIG. 1, a center-feed multilayer co-extrusion die structure is shown in this example.

The die structure comprises an inner ABCDE five-layer structure, and mainly comprises the following parts: the split-flow block comprises an A-layer split-flow block 1, a B-layer split-flow block 2, a C-layer split-flow block 3, a D-layer split-flow block 4, an E-layer split-flow block 5, an A-layer spiral body 6, a B-layer spiral body 7, a C-layer spiral body 8, a D-layer spiral body 9, an E-layer spiral body 10, an outer mould body 11, an adjusting ring 12, a mouth mould 13, a mouth mould plug 14, a screw 15, a screw 16 and a feeding hole 17.

Five-layer feed inlets 17 of ABCDE are positioned at the bottom of the inner layer spiral body 6, are distributed at 45 degrees along the circumference on the same plane with the same central height; the stacked conical central shunting core consists of an A-layer shunting block 1, a B-layer shunting block 2, a C-layer shunting block 3, a D-layer shunting block 4 and an E-layer shunting block 5; the fusant respectively enters the centers of an A-layer shunting block 1, a B-layer shunting block 2, a C-layer shunting block 3, a D-layer shunting block 4 and an E-layer shunting block 5 corresponding to the stacked conical central shunting core after passing through an ABCDE five-layer feed inlet 17, then is shunted by 8 (or 9, 10 and the like according to requirements) equally-divided central shunting holes with the diameter 14 on each layer of shunting block to the corresponding cylindrical runner surfaces of an A-layer spiral body 6, a B-layer spiral body 7, a C-layer spiral body 8, a D-layer spiral body 9 and an E-layer spiral body 10, a one-to-two structure (shown in the attached figure 2) of 8 central shunting runners which are equally and circumferentially and uniformly distributed is arranged on each cylindrical runner surface, a specially designed spiral shunting runner is arranged after the one-to-two structure of the shunting runners are uniformly distributed in the center, and the fusants of the ABCDE layers are converged in a regulating ring 12 after passing through the respective spiral shunting runners, And an annular flow channel consisting of the neck mold 13 and the neck mold plug-in 14 is formed into a functional five-layer film product through inflation, cooling and shaping after the annular flow channel is formed.

The overlapped conical central shunt core is tightly connected with the layer A spiral body 6 through the screw 16, and the conical surface sealing mode is adopted between the two, so that the sealing reliability is improved, the assembly and disassembly are convenient and easy, and the phenomenon that the assembly and disassembly are damaged by pulling on the matching surface is avoided.

The die plug-in 14 is positioned on the die 13 through the cylindrical surface and is tightly pressed and connected through the screw 15, the die plug-in 14 with different die gaps is configured for different functional films, time and labor are saved in replacement, convenience and rapidness are achieved, the problem that the downtime cannot be too long in barrier film production is solved, and the production of the barrier film and various functional films is facilitated.

It is noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A center-fed multilayer co-extrusion die head structure, comprising:

the central shunting core is formed by superposing at least a plurality of shunting blocks, a plurality of central shunting holes are formed in the shunting blocks, and the central shunting holes are communicated with the corresponding feed inlets of the shunting blocks;

the spiral body is provided with a plurality of groups of spiral runners, and each group of spiral runners comprises a main spiral runner communicated with the central diversion hole and a plurality of spiral branch runners connected with the main spiral runner;

and the mold outlet comprises an annular flow channel, and the spiral branch flow channels arranged on the spiral bodies are converged in the annular flow channel.

2. The structure of claim 1, wherein the material inlets corresponding to the shunting blocks of each layer are located on the same plane and are distributed at equal intervals along the circumference.

3. The structure of claim 2, wherein the number of the flow dividing blocks and the spiral bodies is 5.

4. The structure of claim 1, wherein the feed inlets of the diverter blocks are in communication with the central diverter hole at the center of the diverter block.

5. The structure of claim 1, wherein the cross section of the central shunt core is of an isosceles trapezoid structure.

6. The structure of claim 1, wherein the shunt core is in compression connection with the inner helical body through a screw, and the shunt core and the inner helical body are sealed by a conical surface.

7. The center-feed multilayer co-extrusion die structure as claimed in claim 1, wherein said exit orifice comprises: adjusting ring, neck mold plug-in;

the neck ring is positioned in the adjusting ring, an annular flow channel is formed between the neck ring and the adjusting ring, and the annular flow channel is communicated with the spiral branch flow channels arranged on the spiral bodies;

the die insert is positioned on the die through the cylindrical surface and is in compression connection through the screws.

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