Extruder screw for processing PU (polyurethane) material

Abstract

The utility model discloses an extruder screw rod for processing PU (polyurethane) materials, which comprises a screw rod body, and the screw rod body is sequentially provided with a connecting section, a feeding section, a compression section and a homogenizing section along the axial conveying direction; wherein the connecting section is suitable for being installed on an extruder, screw flights are arranged on the peripheral wall of the feeding section and the peripheral wall of the homogenizing section, main threads and auxiliary threads are arranged on the peripheral wall of the compression section, the main threads form a spiral groove in the screw body, the auxiliary threads divide the spiral groove into a solid phase groove and a liquid phase groove, and the solid phase groove and the liquid phase groove are communicated with each other. The pitch of the auxiliary threads in the middle of the compression section in the conveying direction is larger than that of the auxiliary threads in the rear portion. The radial length of the auxiliary thread between the solid phase groove and the liquid phase groove on the screw body is larger than the radial diameter of the main thread. According to the utility model, the solid phase retention time is prolonged, good plasticization is realized under more suitable temperature and shearing conditions, the length-diameter ratio of the screw rod is shortened, the plasticization and mixing effects are improved, and the space is saved for an extruder.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of extruders screw for processing PU material, belong to extruder technical field. BACKGROUND

[0002] At present, with the continuous expansion and diversification of market demand, the processing equipment requirements for different materials are also increasingly refined. PU material is high in shear force and temperature requirement in processing process due to its complex chemical structure and formula, and only under suitable shear force and temperature conditions can stable plasticizing effect be realized.

[0003] After searching the prior art, it is found that the Chinese patent with publication number CN211763374U discloses a PU material extrusion screw, however, it is not suitable for processing PU material in actual use, the homogenization section adopts two-end inclined mixing design, which enhances the mixing effect of the material, but in actual operation, it is easy to cause excessive shear heat, leading to over-plasticization of PU material in the screw, and unable to realize ideal plasticizing quality, affecting the processing effect of the final product. SUMMARY

[0004] The technical problem to be solved by the utility model is to overcome the defects of the prior art, provide an extruder screw for processing PU material, which prolongs the solid-phase residence time, realizes good plasticization under more suitable temperature and shear conditions, shortens the screw length-diameter ratio, improves the plasticizing and mixing effect, and saves space for the extruder.

[0005] To solve the above technical problems, the technical scheme of the utility model is as follows: an extruder screw for processing PU material, comprising:

[0006] A screw body, the screw body is sequentially provided with a connecting section, a feeding section, a compression section and a homogenization section along the axial conveying direction;

[0007] The connecting section is adapted to be installed on the extruder, the outer peripheral wall of the feeding section and the homogenization section is provided with screw ribs, the outer peripheral wall of the compression section is provided with main threads and secondary threads, the main threads form helical grooves on the screw body, the secondary threads separate the helical grooves into solid-phase grooves and liquid-phase grooves, the radial diameter of the secondary threads is greater than that of the main threads, and a double-step barrier head is arranged at the end of the homogenization section.

[0008] Further, the radial depth of the solid-phase groove of the compression section is greater than that of the liquid-phase groove.

[0009] Further, in the compression section, the radial depth of the liquid-phase groove is the same as the helical groove depth of the homogenization section, and the radial depth of the solid-phase groove gradually decreases along the material conveying direction.

[0010] Further, on the compression section, the pitch of the main thread is equal to the outer diameter of the screw body, and the pitch of the secondary thread is 1.5 times the outer diameter of the screw body.

[0011] Further, a key groove is formed on the outer circumferential surface of the connecting section, and the length direction of the key groove extends along the axial direction of the screw body.

[0012] Further, the pitch of the screw flight of the feeding section is greater than the outer diameter of the screw body.

[0013] Further, a spiral exhaust groove is arranged on the connecting section near the connecting part of the feeding section.

[0014] Further, the double-step barrier head comprises a cylinder arranged at the end of the homogenizing section, the diameter of the cylinder is greater than the outer diameter of the screw body, and the cylinder sequentially comprises a first barrier section and a second barrier section along the axial direction, and an annular protrusion is arranged at the boundary between the first barrier section and the second barrier section and at the end of the second barrier section.

[0015] The outer circumferential surface of the first barrier section and the second barrier section is provided with a plurality of spiral grooves.

[0016] The above technical scheme has the following beneficial effects:

[0017] In the utility model, first, the connecting section is installed on the extruder, and the feeding section is connected through the feeding port of the extruder. After the material enters the feeding section from the feeding port, the extruder drives the screw body to rotate, and the material is transported through the screw flight on the feeding section. At the same time in the extruder, the material gradually begins to melt under the shearing heat, and enters the compression section. The solid phase groove of the compression section gradually changes from deep to shallow, and gradually pressurizes the material, so that the pressure gradually increases, and the depth of the liquid phase groove is constant. During the plasticizing process, the solid phase groove in each lead compresses and plasticizes the material, so that the solid phase gradually changes into the liquid phase. The radial height difference between the solid phase groove and the liquid phase groove is designed, so that the material releases part of the pressure after turning into the liquid phase groove, avoiding the generation of excessive shearing heat, so as to optimize the plasticizing effect. The compression section can separate the solid phase and the liquid phase of the plastic particles, so that the material gradually plasticizes.

[0018] The double-step barrier head at the tail of the screw is used for further plasticizing and mixing the material which is not completely plasticized in the compression section, so as to ensure uniform discharging and good plasticizing effect. In addition, the key groove on the outer circumferential surface of the connecting section and the exhaust groove near the feeding section facilitate the installation of the screw body and improve the exhaust effect, which is beneficial to improve the processing performance and efficiency of the extruder.

[0019] In summary, this invention can extend the residence time of solid materials, promoting complete melting of the solid phase, thereby achieving good plasticizing effect under suitable temperature and shear conditions. It significantly shortens the length-to-diameter ratio of the screw, improving both plasticizing and mixing effects while reducing screw length, thus saving space for the multi-layer co-extrusion main unit. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an extruder screw for processing PU materials according to the present invention. Figure 1 ;

[0021] Figure 2 This is a schematic diagram of the structure of an extruder screw for processing PU materials according to the present invention. Figure 2 ;

[0022] Figure 3 for Figure 1 A magnified view of part F in the middle section. Detailed Implementation

[0023] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0024] like Figures 1-3 As shown, an extruder screw for processing PU materials includes:

[0025] The screw body 1 is provided with a connecting section, a feeding section, a compression section and a homogenization section in sequence along the axial conveying direction;

[0026] The connecting section is suitable for installation on an extruder. The outer peripheral walls of the feeding section and the homogenizing section are provided with screw ribs. The outer peripheral wall of the compression section 13 is provided with a main thread 131 and a secondary thread 132. The main thread 131 forms a spiral groove on the screw body 1. The secondary thread 132 divides the spiral groove into a solid phase groove and a liquid phase groove. The radial diameter of the secondary thread 132 is larger than the radial diameter of the main thread 131. A double-stage barrier head 141 is provided at the end of the homogenizing section.

[0027] In this embodiment, as Figures 1-2As shown, first, the connecting section is installed on the extruder, and the feeding section is connected through the feeding port of the extruder. After the material enters the feeding section from the feeding port, the extruder drives the screw body 1 to rotate, and the material is transported through the screw flight on the feeding section. At the same time in the extruder, the material gradually begins to melt due to shear heat, and enters the compression section 13. The solid phase groove of the compression section 13 gradually increases in depth, and the liquid phase groove has a constant depth. During plasticizing, the solid phase groove in each lead compresses and plasticizes the material, so that the solid phase gradually changes into the liquid phase. The radial height difference between the solid phase groove and the liquid phase groove is designed to release part of the pressure after the material is turned into the liquid phase groove, so as to avoid the generation of excessive shear heat, thereby optimizing the plasticizing effect. The compression section 13 can separate the solid phase and the liquid phase of the plastic particles, so that the material is gradually plasticized. The A section is the connecting section, the B section is the feeding section, the C section is the compression section, the D section is the separation section in the compression section, and the E section is the homogenizing section.

[0028] The length of the feeding section is 7 times the outer diameter of the screw body 1, the compression section 3 is divided into a front compression section, a middle compression section and a rear compression section along the conveying direction, and the pitch of the secondary screw thread 12 of the middle compression section is greater than the pitch of the secondary screw thread of the rear compression section. The pitch of the primary screw thread of the rear compression section is equal to the pitch of the screw flight of the feeding section and the homogenizing section.

[0029] Specifically, the radial depth of the solid phase groove of the compression section is greater than the radial depth of the liquid phase groove.

[0030] Specifically, in the compression section, the radial depth of the liquid phase groove remains constant along the material conveying direction, and the constant depth is the same as the helical groove depth of the homogenizing section, and the radial depth of the solid phase groove gradually decreases along the material conveying direction until it is equal to the radial depth of the liquid phase groove.

[0031] Specifically, as shown in the figure, Figures 1-2 Specifically, as shown in the figure,

[0032] In this embodiment, when the material is sufficiently compressed in the solid phase groove, it will naturally flow to the liquid phase groove due to the height difference, thereby realizing effective separation of the solid phase and the liquid phase. At the same time, the radial depth of the solid phase groove gradually decreases along the material conveying direction until it is equal to the depth of the liquid phase groove, and this gradual design makes the material gradually compressed and plasticized during the conveying process.

[0033] Specifically, as shown in the figure, Figures 1-2 Specifically, the outer peripheral surface of the connecting section is provided with a key groove 111, and the length direction of the key groove 111 extends along the axial direction of the screw body 1.

[0034] Specifically, the pitch of the screw flight of the feeding section is greater than the outer diameter of the screw body.

[0035] Specifically, a spiral exhaust groove is arranged at the joint of the connecting section and the feeding section.

[0036] In the embodiment, as shown in the figure, the pitch of the screw flight of the feeding section is larger than the outer diameter of the screw body 1, which can improve the conveying efficiency of the material. Figure 1

[0037] When the material enters the screw body 1, the spiral exhaust groove can effectively exhaust the air carried in the material, preventing the air from forming bubbles in the subsequent processing process and affecting the product quality.

[0038] Specifically, as shown in the figure, the double-stage barrier head 141 includes a cylinder arranged at the end of the homogenizing section, and the diameter of the cylinder is larger than the outer diameter of the screw body 1. Figures 1-3

[0039] A plurality of spiral grooves 142 are arranged on the outer circumferential surfaces of the first barrier section and the second barrier section.

[0040] In the embodiment, as shown in the figure, the double-stage barrier head 141 adopts a special cylinder design, and the diameter of the cylinder is larger than the outer diameter of the screw body 1, which forms a local barrier to the material. Figures 1-3 The double-stage barrier head 141 is divided into a first barrier section and a second barrier section, and a ring-shaped protrusion is arranged at the boundary between the two sections and at the end of the second barrier section, respectively.

[0041] The above-described specific embodiments further illustrate the technical problems solved by the utility model, technical solutions and beneficial effects, and it should be understood that the above-described specific embodiments are only for the utility model and do not limit the utility model.Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.​

Claims

1. An extruder screw for processing PU materials, characterized in that, include: The screw body (1) is provided with a connecting section, a feeding section, a compression section and a homogenization section in sequence along the axial conveying direction; The connecting section is suitable for installation on an extruder. The outer peripheral walls of the feeding section and the homogenizing section are provided with helical ridges. The outer peripheral wall of the compression section is provided with a main thread (131) and a secondary thread (132). The main thread (131) forms a helical groove on the screw body (1). The secondary thread (132) divides the helical groove into a solid phase groove and a liquid phase groove. The radial diameter of the secondary thread (132) is larger than the radial diameter of the main thread (131). A double-stage barrier head (141) is provided at the end of the homogenizing section.

2. The extruder screw for processing PU materials according to claim 1, characterized in that, The radial depth of the solid phase tank in the compression section is greater than the radial depth of the liquid phase tank.

3. The extruder screw for processing PU materials according to claim 1, characterized in that, In the compression section, the radial depth of the liquid phase tank is the same as the spiral groove depth of the homogenization section, and the radial depth of the solid phase tank gradually decreases along the material conveying direction.

4. The extruder screw for processing PU materials according to claim 1, characterized in that, On the compression section, the pitch of the main thread (131) is equal to the outer diameter of the screw body (1), and the pitch of the auxiliary thread (132) is 1.5 times the outer diameter of the screw body (1).

5. The extruder screw for processing PU materials according to claim 1, characterized in that, A keyway (111) is provided on the outer peripheral surface of the connecting section, and the length direction of the keyway (111) extends along the axial direction of the screw body (1).

6. The extruder screw for processing PU materials according to claim 1, characterized in that, The pitch of the screw thread in the feeding section is greater than the outer diameter of the screw body (1).

7. The extruder screw for processing PU materials according to claim 1, characterized in that, On the connecting section, a spiral exhaust groove (121) is provided near the connection of the feeding section.

8. The extruder screw for processing PU materials according to claim 1, characterized in that, The double-stage barrier head (141) includes a cylinder disposed at the end of the homogenization section. The diameter of the cylinder is larger than the outer diameter of the screw body (1). The cylinder is arranged in sequence along the axial direction as a first barrier section and a second barrier section. An annular protrusion is provided at the boundary between the first barrier section and the second barrier section and at the end of the second barrier section. Multiple spiral grooves (142) are provided on the outer peripheral surfaces of both the first barrier segment and the second barrier segment.

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