Improved halogen-free flame-retardant polypropylene extrusion granulation die and double screw extruder
By designing an improved halogen-free flame-retardant polypropylene extrusion granulation die, the problem of uneven melt pressure in the twin-screw extrusion process of halogen-free flame-retardant polypropylene was solved, enabling stable extrusion and continuous production of high-viscosity materials, and improving product quality and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JINYOUNG XIAMEN ADVANCED MATERIALS TECH CO LTD
- Filing Date
- 2025-08-06
- Publication Date
- 2026-07-21
AI Technical Summary
During the twin-screw extrusion granulation process, the high viscosity of halogen-free flame-retardant polypropylene leads to poor melt flowability, uneven melt pressure distribution at the die head, excessively thin or broken strips, and melt stagnation forming dead corners, affecting production efficiency and product quality.
An improved halogen-free flame-retardant polypropylene extrusion granulation die was designed, including a front end face and a rear end face. The connecting part is provided with uniformly distributed extrusion holes and a symmetrical plugging structure. The connecting part forms a specific angle with the first planar part. The extrusion holes adopt a segmented structure and inclined design to optimize the material flow path and pressure distribution.
It significantly improves the stability and continuity of the extrusion process, reduces strip breakage and material accumulation, and enhances product quality and production efficiency. It is suitable for high-viscosity halogen-free flame-retardant polypropylene systems.
Smart Images
Figure CN224527956U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of twin-screw extrusion granulation technology, and in particular to an improved halogen-free flame-retardant polypropylene extrusion granulation die and twin-screw extruder. Background Technology
[0002] Halogen-free flame-retardant reinforced polypropylene contains no halogens (such as bromine and chlorine) and does not release toxic gases (such as hydrogen halides) when burning, complying with environmental regulations such as RoHS and REACH, and is considered an environmentally friendly polymer material. It forms a dense char layer through a condensed phase charring mechanism, effectively isolating oxygen and heat sources, achieving a flame retardant rating of UL94 V0 (1.6mm), and is widely used in electronics, automotive parts, and other fields.
[0003] In existing technologies, the high dosage of halogen-free flame retardants and their poor temperature resistance, coupled with the need for glass fiber reinforcement, significantly increase system viscosity and deteriorate melt flowability. During twin-screw extrusion granulation, uneven melt pressure distribution at the die head results in excessively low extrusion pressure on both sides, leading to excessively thin strips or even breakage during extrusion. Frequent strip breakage necessitates shutdown for cleaning, reducing production efficiency and increasing scrap rate. Melt stagnation creates dead zones, causing high-temperature decomposition and carbonization of the material. Traditional improvements focus on adjusting the formulation or process parameters, but cannot fundamentally address the problem of uneven flow field distribution at the die head.
[0004] Therefore, those skilled in the art urgently need a dedicated die structure design for high-viscosity halogen-free flame retardant systems. Utility Model Content
[0005] To overcome the shortcomings of the prior art, this utility model provides an improved halogen-free flame-retardant polypropylene extrusion granulation die, including a die body, the die body including a front end face and a rear end face, the front end face including a first planar portion, a connecting portion and a second planar portion arranged sequentially from top to bottom, the extension directions of the first planar portion and the second planar portion are parallel to each other, and the connecting portion connects the first planar portion and the second planar portion.
[0006] The connecting part is provided with a plurality of uniformly distributed extrusion holes, and at least two pairs of symmetrically arranged secondary edge holes are configured as a plugging structure.
[0007] Based on the above scheme, further, the extension direction of the connecting part forms an angle α with the first planar part, and the range of the angle α is 15°-45°.
[0008] Based on the above scheme, the extrusion hole is further defined as a through hole connecting the front end face and the rear end face, comprising a first section, a transition section and a second section connected sequentially from the front end face to the rear end face; the cross-sectional area of the first section is greater than the cross-sectional area of the second section; the cross-sectional area of the transition section decreases continuously from the first section to the second section.
[0009] Based on the above scheme, the extrusion hole is further inclined, with the opening near the front end face being lower than the opening near the rear end face.
[0010] Based on the above scheme, the number of plugging structures configured in the extrusion hole is further 4-8.
[0011] Based on the above scheme, the first and second planar portions are further provided with multiple openings, and the template body passes through the openings by means of fasteners, thereby connecting with the external extruder head.
[0012] Based on the above solution, a slot is further provided in the longitudinal center of the rear end face.
[0013] Based on the above scheme, the lower end face of the die body is provided with at least one semi-circular groove.
[0014] Based on the above scheme, the material of the die body is mold steel, 38CrMoAl, 34CrAlNi7, or 34CrAlMo5.
[0015] This utility model also provides a twin-screw extruder, wherein the die of the twin-screw extruder is the improved halogen-free flame-retardant polypropylene extrusion granulation die as described above.
[0016] Compared with existing technologies, the improved halogen-free flame-retardant polypropylene extrusion granulation die provided by this utility model features a first planar portion, a connecting portion, and a second planar portion arranged sequentially on the front end face, with at least two pairs of secondary edge plugging structures symmetrically configured in the connecting portion. This design forces the melt flow path inside the die head to shift towards the edge region, significantly increasing the pressure intensity of the outermost extrusion orifice and avoiding breakage and excessively thin edge strips due to insufficient edge pressure. Simultaneously, the plugging structure optimizes the flow field distribution in the connecting portion, eliminating melt stagnation dead zones, reducing material accumulation in the die head, and preventing high-temperature decomposition and carbonization of the material. Its symmetrical plugging design ensures balanced pressure distribution, and in conjunction with the connecting portion structure, this die is suitable for high-viscosity halogen-free flame-retardant polypropylene systems. While maintaining the original production efficiency, it reduces the breakage frequency and significantly improves granulation continuity and product yield. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 A three-dimensional structural diagram of the extrusion granulation die provided by this utility model;
[0019] Figure 2 This is a front view of the extrusion granulation die provided by this utility model;
[0020] Figure 3 This is a cross-sectional view along the AA direction of the extrusion granulation die provided by this utility model.
[0021] Figure label:
[0022] 10. Die body, 11. Front end face, 12. Rear end face, 13. First flat part, 14. Connecting part, 15. Second flat part, 16. Extrusion hole, 17. Hole plugging structure, 18. First section, 19. Transition section, 20. Second section, 21. Opening, 22. Slot, 23. Semicircular groove. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0024] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0025] To provide a dedicated die structure design for high-viscosity halogen-free flame-retardant systems, this utility model provides the following... Figure 1-3The improved halogen-free flame-retardant polypropylene extrusion granulation die shown is shown.
[0026] like Figure 1 As shown, the structure includes a die body 10, which includes a front end face 11 and a rear end face 12. The front end face 11 includes a first planar portion 13, a connecting portion 14 and a second planar portion 15 arranged sequentially from top to bottom. The extending directions of the first planar portion 13 and the second planar portion 15 are parallel to each other. The connecting portion 14 connects the first planar portion 13 and the second planar portion 15.
[0027] The connecting part 14 is provided with a plurality of uniformly distributed extrusion holes 16, and at least two pairs of symmetrically arranged secondary edge holes are configured as hole-blocking structures 17.
[0028] In the above solution, by configuring at least two pairs of symmetrically arranged secondary edge holes on the connecting part 14 as hole-blocking structures 17, the material pressure distribution of the die body 10 during the extrusion process can be effectively optimized. In particular, it can improve the extrusion pressure in the two edge areas, thereby improving the problems of excessively thin edge strips and easy breakage that are common in traditional dies, and ensuring the uniformity and stability of the extruded material strip. At the same time, this hole-blocking design reduces the diversion of material in non-critical areas, accelerates the overall material flow speed in the die, and reduces the accumulation of material caused by long-term retention. This is conducive to improving production efficiency and reducing material waste or product quality fluctuations caused by material accumulation.
[0029] In one embodiment, the extending direction of the connecting portion 14 forms an angle α with the first planar portion 13, and the angle α ranges from 15° to 45°.
[0030] Preferably, the included angle α is in the range of 15°.
[0031] With the above solution, the extension direction of the connecting part 14 forms an angle α of 15°-45° with the first flat part 13. This angle design can better adapt to the flow characteristics of the material in the die, reduce the material flow resistance, and allow the material to enter the extrusion hole 16 more smoothly, further improving the stability of the extrusion process. At the same time, it also helps to reduce the pressure loss inside the die and ensure the consistency of the material output from each extrusion hole 16.
[0032] In one embodiment, such as Figure 3 As shown, the extrusion hole 16 is a through hole connecting the front end face 11 and the rear end face 12, including a first section 18, a transition section 19 and a second section 20 connected sequentially from the front end face 11 to the rear end face 12; the cross-sectional area of the first section 18 is greater than the cross-sectional area of the second section 20; the cross-sectional area of the transition section 19 decreases continuously from the first section 18 to the second section 20.
[0033] Using the above scheme, the extrusion orifice 16 adopts a segmented structure of a first section 18, a transition section 19, and a second section 20. The cross-sectional area of the first section 18 is larger than that of the second section 20, and the cross-sectional area of the transition section 19 decreases continuously. This design can play a good role in guiding and pressurizing the material, so that the material can achieve a smooth transition in the extrusion orifice 16 and avoid flow turbulence caused by abrupt changes in cross-section. It is especially suitable for high-viscosity halogen-free flame-retardant polypropylene materials and helps to improve the density and uniformity of the extruded strip.
[0034] In one embodiment, such as Figure 3 As shown, the extrusion hole 16 is inclined, and its opening near the front end face 11 is lower than the opening near the rear end face 12.
[0035] With the above solution, the extrusion hole 16 is inclined and the opening near the front end face 11 is lower than the opening near the rear end face 12. This can conform to the flow direction of the material in the die, reduce the impact and resistance when the material enters the extrusion hole 16, and make the material pass through the extrusion hole 16 more smoothly, reducing the energy loss inside the die. At the same time, it is also conducive to reducing the accumulation of material at the inlet of the extrusion hole 16, further alleviating the problem of material accumulation.
[0036] In one embodiment, such as Figure 2 As shown, the number of holes 16 configured as plugging structures 17 is 4-8.
[0037] By adopting the above scheme, the number of plugging structures 17 in the extrusion orifice 16 is set to 4-8, which can ensure the optimization of pressure in the edge area while avoiding the overall extrusion efficiency from being reduced due to excessive plugging. Through reasonable quantity configuration, a balance is achieved between material pressure distribution and extrusion output, meeting the actual needs under different production conditions.
[0038] It should be noted that those skilled in the art can adjust the number of plugging structures 17 according to actual needs during the actual production process, based on the number of extrusion holes 16 on the die.
[0039] Preferably, the plugging structure 17 can be formed by rivet sealing or by welding.
[0040] In one embodiment, such as Figure 1 or Figure 2 As shown, the first flat portion 13 and the second flat portion 15 are provided with a plurality of openings 21. The template body passes through the openings 21 by means of fasteners, and is then connected to the external extruder head.
[0041] In the above scheme, the design of multiple openings 21 on the first flat part 13 and the second flat part 15 enables the die body 10 to be securely connected to the external extruder head through fasteners, ensuring the installation stability of the die during high-speed extrusion and avoiding positional displacement caused by factors such as vibration.
[0042] In one embodiment, such as Figure 3 As shown, a slot 22 is provided in the longitudinal center of the rear end face 12.
[0043] In the above solution, the slot 22 opened in the longitudinal middle of the rear end face 12 can form a precise fit with the corresponding structure on the extruder head, which not only facilitates the quick positioning and installation of the die, but also enhances the connection and sealing between the die and the head, preventing material leakage at the connection.
[0044] In one embodiment, such as Figure 1 or Figure 2 As shown, the lower end face of the die body 10 is provided with at least one semi-circular groove 23.
[0045] By adopting the above solution, at least one semi-circular groove 23 provided on the lower end face of the die body 10 can serve as an auxiliary positioning or installation structure, which facilitates the fixing or adjustment of the die during the production process, improves the convenience of die installation and maintenance, and can also cooperate with other auxiliary components according to actual needs to enhance the stability of the overall structure.
[0046] In one embodiment, the die body 10 is made of mold steel, 38CrMoAl, 34CrAlNi7, or 34CrAlMo5.
[0047] Preferably, the die body 10 is made of 38CrMoAl.
[0048] This utility model also provides a twin-screw extruder, wherein the die of the twin-screw extruder is the improved halogen-free flame-retardant polypropylene extrusion granulation die as described above.
[0049] The twin-screw extruder using the improved halogen-free flame-retardant polypropylene extrusion granulation die described above can effectively solve the problems of uneven edge strips, easy strip breakage, and material accumulation that exist when traditional dies are used to process halogen-free flame-retardant polypropylene materials. This improves the product quality and production efficiency of extrusion granulation, and gives the twin-screw extruder superior performance and wider applicability in processing difficult-to-process materials such as halogen-free flame-retardant polypropylene.
[0050] Although this document frequently uses terms such as mold body, front end face, rear end face, first flat part, connecting part, and second flat part, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this utility model; interpreting them as any additional limitation would contradict the spirit of this utility model.
[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. An improved halogen-free flame-retardant polypropylene extrusion granulation die, characterized in that: The device includes a die body (10), which includes a front end face (11) and a rear end face (12). The front end face (11) includes a first planar portion (13), a connecting portion (14), and a second planar portion (15) arranged sequentially from top to bottom. The extension directions of the first planar portion (13) and the second planar portion (15) are parallel to each other. The connecting portion (14) connects the first planar portion (13) and the second planar portion (15). The connecting part (14) is provided with a plurality of uniformly distributed extrusion holes (16), and at least two pairs of symmetrically arranged secondary edge holes are configured as a plugging structure (17).
2. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The connecting part (14) extends in a direction that forms an angle α with the first planar part (13), and the angle α ranges from 15° to 45°.
3. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The extrusion hole (16) is a through hole connecting the front end face (11) and the rear end face (12), including a first section (18), a transition section (19) and a second section (20) connected sequentially from the front end face (11) to the rear end face (12); the cross-sectional area of the first section (18) is greater than the cross-sectional area of the second section (20); the cross-sectional area of the transition section (19) decreases continuously from the first section (18) to the second section (20).
4. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 3, characterized in that: The extrusion hole (16) is inclined, with its opening near the front end face (11) being lower than the opening near the rear end face (12).
5. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The number of plugging structures (17) configured in the extrusion hole (16) is 4-8.
6. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The first flat portion (13) and the second flat portion (15) are provided with a plurality of openings (21), and the mouth template body is connected to the external extruder head by means of fasteners passing through the openings (21).
7. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The rear end face (12) has a slot (22) in the longitudinal middle.
8. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The lower end face of the die body (10) is provided with at least one semi-circular groove (23).
9. The improved halogen-free flame-retardant polypropylene extrusion granulation die according to claim 1, characterized in that: The die body (10) is made of mold steel, 38CrMoAl, 34CrAlNi7, or 34CrAlMo5.
10. A twin-screw extruder, characterized in that: The die of the twin-screw extruder is the improved halogen-free flame-retardant polypropylene extrusion granulation die as described in any one of claims 1-9.