A stretch-reinforced mixing element

Abstract

This invention relates to the field of injection molding technology, specifically disclosing a stretch-reinforced mixing element, including at least one stretching component and at least one shearing component. It can function as a single screw in an injection molding machine, with the material conveying direction set from the stretching component to the shearing component. Various plastic masterbatches are fed into the injection molding machine's feed inlet, forming a molten flow under high temperature. The flow is then diverted by the stretching component, which stretches the flow before it enters the shearing component. The shearing component shears and disperses the flow, ensuring thorough mixing. This combination of dispersion, stretching, and shearing improves the mixing effect and prevents degradation of shear-sensitive material molecular chains due to the lack of significant shear force, thus avoiding any impact on the material's properties during the mixing process.

Description

Technical Field

[0001] This invention relates to the field of injection molding technology, and in particular to a stretch-reinforced compounding element. Background Technology

[0002] Extruders are the most widely used equipment in the plastic molding and processing industry. The mixing element is an important component of the extruder. Generally, single-screw or twin-screw mixing elements are used. Common single-screw mixing elements include pin type, barrier type, and pineapple type, but their shearing effect is weak and their dispersion and mixing effect is not good, which leads to certain limitations in their industrial application.

[0003] To improve the dispersion and mixing effect of materials, structural improvements are often made to single-screw extruders. One example of such a single-screw extruder is disclosed in Chinese Patent Publication No. CN102303402B, which includes a housing and a screw. The screw is rotatably disposed in a rotating cavity within the housing. A main pusher is provided on the outer circumferential surface of the screw, extending spirally. The housing has a feed inlet and a discharge outlet. The screw has a feed section and a discharge section. The feed section of the screw is located at the feed inlet of the housing, and the discharge section is located inside the discharge outlet of the housing. A spirally extending helical structure is provided on the outer circumferential surface of the feed section. The pitch of the helical structure differs from the pitch of the main pusher on the feed section. The helical structure and the main pusher intersect at least once, forming a sharp-angled shear structure at the intersection.

[0004] Most existing single-screw extruders achieve mixing by enhancing shearing and diversion intensity. While high-intensity shearing can achieve dispersion and mixing, it can easily degrade the molecular chains of shear-sensitive materials, reducing the material's performance.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a stretch-reinforced compounding element to solve the problem that conventional single-screw extruders can achieve dispersion and mixing effects through high-intensity shearing, but the molecular chains of shear-sensitive materials are easily degraded, resulting in a reduction in the performance of the material itself.

[0007] A stretch-reinforced compound element, comprising:

[0008] At least one stretching component, the stretching component comprising a first rotating body capable of rotating about a rotational central axis and a plurality of baffles circumferentially distributed around the first rotating body, wherein a fine groove for material to pass through is formed between two adjacent baffles;

[0009] At least one shearing component, the shearing component includes a second rotating body capable of rotating around a rotation center axis, the outer surface of the second rotating body has a plurality of spiral ridges and spiral grooves formed between adjacent two of the ridges, and the depth of the spiral grooves gradually changes along the spiral direction;

[0010] The stretching component is in transmission connection with the shearing component.

[0011] Specifically, the baffle of at least one of the stretching components is a "Shen" shaped baffle.

[0012] Specifically, the baffle of at least one of the stretching components is an S-shaped baffle.

[0013] Specifically, the included angle between the center line along the length direction of the S-shaped baffle and the tangent line of the first rotating body is α, satisfying the following condition: 0° ≤ α < 90°.

[0014] Specifically, α is 0° or 30°.

[0015] Specifically, a plurality of trapezoidal curved surfaces with opposite directions and complementary arrangements are provided on the outer side surface of the first rotating body in the circumferential direction, and the S-shaped baffle straddles adjacent two of the trapezoidal curved surfaces.

[0016] Specifically, the depth of at least one of the spiral grooves decreases from large to small along the spiral direction; the depth of at least one of the spiral grooves increases from small to large along the spiral direction.

[0017] Specifically, a baffle for blocking the flow is provided at the place where the depth of the spiral groove is the smallest.

[0018] Specifically, there are a plurality of the stretching components and a plurality of the shearing components, the stretching components and the shearing components are in transmission connection and are arranged alternately along the axial direction.

[0019] Specifically, the first rotating body and the second rotating body are integrally connected.

[0020] Advantages of the present invention:

[0021] For a stretching enhanced mixing element of the present invention, at least one stretching component and at least one shearing component are provided, which can be used as a single screw in an injection molding machine, and the direction from the stretching component to the shearing component is set as the material conveying direction. A variety of plastic masterbatches are fed from the feed port of the injection molding machine, and after being affected by high temperature, a molten flowing material is formed. The flowing material is branched by the stretching component, and during the branching process, the flowing material is stretched, and then enters the shearing component. The shearing component is used for shearing and dispersing, so that the flowing material is fully mixed. Mixing is carried out by combining dispersion, stretching and shearing, which can not only improve the mixing effect, but also for the molecular chains of shear-sensitive materials, since there is no large shearing force, their degradation will not be caused, and the influence on the performance of the material itself during the mixing process can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 Is a perspective view of the kneading element of Example 1;

[0024] Figure 2 Is a front view of the kneading element of Example 1;

[0025] Figure 3 Is a left view of the first stretching member of Example 1;

[0026] Figure 4 Is a front view of the first stretching member of Example 1;

[0027] Figure 5 Is a left view of the second stretching member of Example 2;

[0028] Figure 6 Is a front view of the second stretching member of Example 2;

[0029] Figure 7 Is a left view of the second stretching member of Example 3;

[0030] Figure 8 Is a front view of the second stretching member of Example 3;

[0031] Figure 9 Is a left view of the second stretching member of Example 1;

[0032] Figure 10 Is a front view of the second stretching member of Example 1;

[0033] Figure 11 Is a perspective view of the second stretching member of Example 1;

[0034] Figure 12 Is a front view of the shearing member of Example 1;

[0035] Figure 13 Is a front view before the complete screw is cut.

[0036] The reference numerals are: stretching members 10a, 10d; first rotating bodies 11a, 11b, 11c, 11d; fine grooves 13a, 13b, 13c, 13d; shearing member 20; second rotating body 21; thread edges 22; thread grooves 23a, 23b; "Shen"-shaped baffle 12a; S-shaped baffles 12b, 12c, 12d; trapezoidal curved surface 14; baffles 24a, 24b; complete screw 30. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention provides a stretching-enhanced mixing element. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the following further describes the present invention in detail with reference to the attached drawings and by way of examples. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0039] Embodiment 1

[0040] This embodiment discloses a stretching-enhanced mixing element. Please refer to Figures 1-2 As shown, the mixing element includes stretching components 10a, a shearing component 20, stretching components 10b, and a shearing component 20 arranged in sequence along the axis. It should be noted that the mixing element of this embodiment can be applied to the injection molding process as a single screw in an injection molding machine, and it is set that the direction from the stretching component 10a to the shearing component 20 is the material conveying direction. Multiple plastic masterbatches are fed from the feed port of the injection molding machine, and after being subjected to high temperature, they form a molten flow material. The flow material undergoes primary splitting through the stretching component 10a, and the flow material is stretched during the splitting process, and then enters the first shearing component 20. The shearing component 20 is used for shearing and dispersing to mix the flow material. Then, it passes through the stretching component 10b for secondary splitting, stretching and crushing the flow material. Finally, it passes through the second shearing component 20, and the shearing component 20 is used for shearing and dispersing to fully mix the flow material, and finally a good mixing effect of the product is obtained.

[0041] The above-mentioned stretching component 10a is as Figures 3-4 As shown, the stretching component 10a includes a first rotating body 11a that can rotate around the rotation center axis and a number of "Shen" - shaped baffle plates 12a circumferentially distributed around the first rotating body 11a. A fine groove 13a for the flow material to pass through is formed between two adjacent "Shen" - shaped baffle plates 12a. Before the flow material passes through the fine groove 13a, it changes from a wide channel to a narrow channel, and a strong contraction and stretching effect is formed at the position of the fine groove 13a, thereby generating a strong stretching stress on the flow material and achieving a better dispersion and mixing effect;

[0042] It should be noted that the structure of the "Shen"-shaped baffle 12a is not limited to a regular "Shen" character structure. Its edges should be designed to be smooth according to the flow direction of the flowing material. Moreover, the channel between two "Shen"-shaped baffles 12a should be divided by the narrow groove 13a. The channel towards the material inlet end is a channel that changes from wide to narrow, and the channel towards the material outlet end is a channel that changes from narrow to wide. The narrow groove 13a is the narrowest position of the entire channel. When the material passes through the narrow groove 13a from the wide channel, the first stage of flow splitting, contraction, and stretching is achieved.

[0043] It should be noted that by reasonably setting the size, quantity, and arrangement interval of the "Shen"-shaped baffle 12a, etc., the quantity and width of the narrow groove 13a can be adjusted, thereby enhancing the flow splitting effect and the contraction and stretching effect. This is an adjustment that can be easily made based on the inventive concept of this application. For the conventional adjustments of the size, quantity, and arrangement interval of the "Shen"-shaped baffle 12a for the purpose of actual production requirements based on this invention, they are all within the protection scope of this invention.

[0044] Of course, the above-mentioned "Shen"-shaped baffle 12a is only the preferred embodiment of this application. In other embodiments, baffles such as those with a rhombus-shaped orthographic projection surface, a triangular orthographic projection surface, a frustum-shaped orthographic projection surface, etc. can also be used. Moreover, the above-mentioned baffles all meet the following conditions: a narrow groove is formed between two adjacent baffles, and the channel at the end of the narrow groove towards the material inlet is a channel that changes from wide to narrow. Just meeting the above conditions is sufficient. The structure of the baffle is not limited to the "Shen"-shaped baffle 所公开的12a in this embodiment. Other equivalent transformations are all extensions under the inventive concept of this invention and are all within the protection scope of this invention.

[0045] The above-mentioned shear component 20 is as Figure 2 and Figure 12 shown. The shear component 20 includes a second rotating body 21 that can rotate around the rotation center axis. The outer surface of the second rotating body 21 has a plurality of spiral ridges 22 and spiral grooves 23a and 23b formed between two adjacent ridges 22. The depths of the spiral grooves 23a and 23b both gradually change along the spiral direction, and it has a strong shearing effect. The flowing material flows through the spiral grooves 23a and 23b with depths that gradually change along the spiral direction, and the volume flow rate of the flowing material (the volume of fluid flowing through a certain section of the pipeline per unit time is called the volume flow rate of this cross-section) continuously changes, improving the shearing effect.

[0046] It should be noted that the shear component 20 is provided with four channels, including two inlet channels and two outlet channels, but it is not limited to four channels. In other embodiments, six channels, eight channels, etc. can be used. For other equivalent transformations of the number of channels, they are all extensions under the inventive concept of this invention and are all within the protection scope of this invention.

[0047] Among them, the depth of the spiral grooves 23a of the two inlet flow channels decreases from large to small along the spiral direction, from the bottom diameter of the second rotating body 21 to the outer diameter; the depth of the spiral grooves 23a of the inlet flow channels gradually changes, and the volume of the fluid gradually decreases as it passes through the spiral grooves 23a, which can increase shear, reduce pressure drop, ensure plasticizing effect, and improve transmission efficiency.

[0048] The spiral grooves 23b of the two outlet flow channels gradually deepen from the outer diameter of the second rotating body 21 to the bottom diameter; the gradual change in depth of the spiral grooves 23b of the outlet flow channels can promote backflow, increase the residence time of the flow, and further enhance the melting and plasticizing.

[0049] The shearing component 20 has two parts, which are made of, for example Figure 13 The complete screw 30 is cut and divided into two shearing parts 20. Each shearing part 20 has four flow channels. If the complete screw 30 before cutting only has one gradient and one shear, then cutting it in this embodiment to have two shearing parts 20 can be understood as changing from one gradient and one shear to two gradients and two shears, further improving the shearing effect.

[0050] Please refer to Figure 12 As shown, a baffle 24a is provided at the minimum depth of the screw groove 23a to prevent the material in the upper inlet channel from flowing directly into the lower outlet channel, and to reduce pressure drop, reduce back pressure, and ensure conveying efficiency.

[0051] Please refer to Figure 12 As shown, a baffle 24b is provided at the minimum depth of the screw channel 23b to prevent the material from flowing directly into the inlet channel from the baffle 24b. This ensures that the material can flow back through the outlet channel, further enhancing the melting and plasticizing of the material.

[0052] As a further extension of the solution, the screw grooves 23b of the two outlet channels can be deepened to reduce the pressure drop caused by the baffle 24b, that is, to reduce the back pressure and ensure the material conveying efficiency.

[0053] The aforementioned tension member 10d, as shown Figures 9-11 As shown, the stretching component 10d includes a first rotating body 11d that can rotate around the rotation center axis and a plurality of S-shaped baffles 12d distributed circumferentially around the first rotating body 11d. A fine groove 13d is formed between two adjacent S-shaped baffles 12d for the material to pass through. When the material flows, it is interrupted by the S-shaped baffles 12d and can only flow along the end face of the S-shaped baffles 12d facing the material feeding direction. When it passes through the fine groove 13d, a strong contraction and stretching effect is formed at the fine groove 13d, thereby generating a strong tensile stress on the material and achieving a better dispersion and mixing effect.

[0054] It should be noted that the structure of the S-shaped baffle 12d is not limited to a regular "S" shape. It should be adapted to the flow direction of the material. Furthermore, a narrow channel 13d will be formed between the two S-shaped baffles 12d, and the end face facing the material feed has a long blocking path, so that the material can only pass through the narrow channel 13d and the S-shaped baffle 12d to achieve a second diversion, contraction and stretching.

[0055] It should be noted that by reasonably setting the size, quantity, and arrangement interval of the S-shaped baffles 12d, the number and width of the fine channels 13d can be adjusted, thereby improving the diversion effect and the contraction and stretching effect. This is an adjustment that can be easily made based on the inventive concept of this application. Conventional adjustments to the size, quantity, and arrangement interval of the S-shaped baffles 12d made based on this invention for actual production needs are all within the protection scope of this invention.

[0056] Of course, the S-shaped baffle 12d described above is only a preferred embodiment of this application. In other embodiments, baffles such as those in the shape of an "I" or those in the shape of a wave can also be used. Moreover, all of the above baffles meet the following condition: a narrow groove is formed between two adjacent baffles, and the obstruction of the baffles allows the flow to pass only along the narrow groove. As long as the above condition is met, the structure of the baffle is not limited to the S-shaped baffle 12d disclosed in this embodiment. Other equivalent modifications are extensions of the concept of this invention and are all within the protection scope of this invention.

[0057] It should be noted that the angle between the center line of the S-shaped baffle 12d along its length and the tangent of the first rotating body 11d is α, where α is 0°. Of course, in other embodiments, the S-shaped baffle 12c can be designed with a certain tilt angle. The tilt angle can be set according to the specific feeding situation. If the material obstruction phenomenon is serious, the tilt angle can be appropriately increased.

[0058] Please refer to Figures 9-11 As shown, the outer side of the first rotating body 11d is provided with several trapezoidal curved surfaces 14 arranged in opposite directions and complementary in the circumferential direction. The S-shaped baffle 12d spans two adjacent trapezoidal curved surfaces 14. The trapezoidal curved surfaces 14 have a certain curvature and are arranged in a complementary manner between each other. The whole is distributed in a circle on the outer side of the first rotating body 11d. Its function in this invention is to enhance turbulence, reduce pressure drop, reduce back pressure, and ensure stable material conveying.

[0059] Please refer to Figure 12As shown, the stretching component 10a, shearing component 20, stretching component 10b, and shearing component 20 are arranged sequentially along the axis. Moreover, the first rotating body 11a is integrally connected to the second rotating body 21 of the first shearing component 20, the second rotating body 21 of the first shearing component 20 is integrally connected to the first rotating body 11d, and the first rotating body 11d is integrally connected to the second rotating body 21 of the second shearing component 20. The entire mixing element is integrally formed, which can ensure the synchronous rotation between the various components.

[0060] Example 2

[0061] Please refer to Figure 5 and Figure 6 As shown, this embodiment discloses a stretch-reinforced mixing element. Compared with Embodiment 1, the difference lies in that the first stretching component includes a first rotating body 11b capable of rotating around a central axis of rotation and several S-shaped baffles 12b circumferentially distributed around the first rotating body 11b. A fine groove 13b is formed between two adjacent S-shaped baffles 12b for the material to pass through. When the material flows, it is interrupted by the S-shaped baffles 12b and can only flow along the end face of the S-shaped baffles 12b facing the material feeding direction. When passing through the fine groove 13b, a strong contraction and stretching effect is formed at the fine groove 13b, thereby generating a strong tensile stress on the material and achieving a better dispersion and mixing effect. The outer surface of the first rotating body 11b does not adopt a trapezoidal curved surface.

[0062] Example 3

[0063] Please refer to Figure 7 and Figure 8 As shown, this embodiment discloses a stretch-reinforced mixing element. Compared with Embodiment 1, the difference lies in that the first stretching component includes a first rotating body 11c capable of rotating around a central axis of rotation and several S-shaped baffles 12c circumferentially distributed around the first rotating body 11c. A fine groove 13c for material flow is formed between two adjacent S-shaped baffles 12c. When the material flows, it is interrupted by the S-shaped baffles 12c and can only flow along the end face of the S-shaped baffles 12c facing the material feeding direction. When passing through the fine groove 13c, a strong contraction and stretching effect is formed at the fine groove 13c, thereby generating a strong tensile stress on the material and achieving a better dispersion and mixing effect. The outer surface of the first rotating body 11c does not adopt a trapezoidal curved surface. The angle between the center line of the S-shaped baffle 12c along the length direction and the tangent of the first rotating body 11c is α, where α is 30°, to avoid material blockage.

[0064] Of course, it is not limited to 30°. In other embodiments, the S-shaped baffle 12c can be designed with other tilt angles, such as 10°, 15°, 45°, etc. The tilt angle can be set according to the specific feeding situation. If the material resistance phenomenon is serious, the tilt angle can be appropriately increased. The tilt angle is the same as the spiral direction of the shearing component.

[0065] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present invention.

Claims

1. A stretch-reinforced compounding element, characterized in that, Comprising: At least one stretching component, the stretching component includes a first rotating body capable of rotating around a rotation center axis and a plurality of baffle plates circumferentially distributed around the first rotating body, and fine grooves for the flow material to pass through are formed between adjacent two of the baffle plates; At least one shearing component, the shearing component includes a second rotating body capable of rotating around the rotation center axis, the outer surface of the second rotating body has a plurality of spiral ridges and spiral grooves formed between adjacent two of the ridges, and the depth of the spiral grooves gradually changes along the spiral direction; The stretching component is in transmission connection with the shearing component, there are a plurality of the stretching components and a plurality of the shearing components, the stretching components and the shearing components are in transmission connection and are arranged alternately along the axial direction; The depth of at least one of the spiral grooves decreases from large to small along the spiral direction; the depth of at least one of the spiral grooves increases from small to large along the spiral direction; The shearing component is provided with four channels, including two inlet flow channels and two outlet flow channels. Among them, the depth of the spiral grooves of the two inlet flow channels decreases from large to small along the spiral direction, from the bottom diameter to the outer diameter of the second rotating body; the spiral grooves of the two outlet flow channels change from shallow to deep, from the outer diameter to the bottom diameter of the second rotating body.

2. The stretch-reinforced compounding element according to claim 1, characterized in that, The baffle plate of at least one of the stretching components is a "Shen" - shaped baffle plate.

3. The stretch-reinforced compounding element according to claim 1, characterized in that, The baffle plate of at least one of the stretching components is an S - shaped baffle plate.

4. The stretch-reinforced compounding element according to claim 3, characterized in that, The included angle between the center line in the length direction of the S - shaped baffle plate and the tangent line of the first rotating body is α, satisfying the following condition: 0° ≤ α < 90°.

5. The stretch-reinforced compounding element according to claim 4, characterized in that, α is 6. The stretch-reinforced compounding element according to claim 3, characterized in that, ​ 7. The stretch-reinforced compounding element according to claim 1, characterized in that, ​ 8. The stretch-reinforced compounding element according to claim 1, characterized in that, ​

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