Polypropylene (PP) three-layer co-extrusion foaming sheet middle foaming core layer extrusion charging barrel

Abstract

The utility model relates to an extrusion charging barrel for a middle foaming core layer of a PP three-layer co-extrusion foaming sheet, which comprises a barrel body and an extrusion screw positioned in the barrel body, and a compression section, a plasticizing section, a barrier section and a mixing section are sequentially arranged on the extrusion screw along the direction from a feed port to an extrusion port of the barrel body. According to the utility model, materials can be fully mixed in the barrel body, bubbles and cavities in the materials are reduced, the homogeneity of the materials is improved, and foaming pores of a middle foaming core layer are more uniform and fine, so that the stability of the quality of the middle foaming core layer is improved.

Description

Technical Field

[0001] This utility model relates to the technical field of PP foam sheet production equipment, specifically to an extrusion cylinder for the middle foam core layer of a PP three-layer co-extruded foam sheet. Background Technology

[0002] In the existing technology, the screw inside the extrusion cylinder for producing the middle foam core layer of PP three-layer co-extruded foamed sheets has only a single spiral blade structure. During the extrusion molding process, the foam core layer has large and uneven foam pores, resulting in unstable production quality. Summary of the Invention

[0003] The purpose of this utility model is to overcome the shortcomings of the prior art and provide an extrusion cylinder for the middle foam core layer of PP three-layer co-extruded foamed sheet.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A PP three-layer co-extruded foamed sheet intermediate foam core layer extrusion cylinder includes a cylinder body and an extrusion screw located inside the cylinder body. One end of the cylinder body has a feed port and the other end of the cylinder body has an extrusion port. The extrusion screw is provided with a compression section, a plasticizing section, a barrier section and a mixing section in sequence along the direction from the feed port to the extrusion port of the cylinder body.

[0006] The compression section is provided with a first spiral blade mounted on the extrusion screw;

[0007] The plasticizing section is equipped with a second spiral blade that follows two different trajectories on the extrusion screw;

[0008] The surface of the barrier section has multiple spaced spiral barrier grooves.

[0009] The mixing section is provided with multiple mixing blocks, which are spirally spaced and staggered in axial position.

[0010] The cylinder wall has independent heat exchange spiral channels corresponding to the compression section, plasticizing section, barrier section and mixing section, and heat transfer oil circulates in each heat exchange spiral channel.

[0011] Furthermore, the compound block is a rectangular or rhomboid protrusion.

[0012] Furthermore, the compression section and the plasticizing section are connected by a variable diameter section, which gradually increases in size along the material flow direction.

[0013] Furthermore, the barrier segment is a two-segment barrier structure.

[0014] Furthermore, the pitches of the two second helical blades on the plasticizing section are different.

[0015] Furthermore, the heat exchange spiral channel is a double spiral channel.

[0016] By adopting the above technical solution, the beneficial effects of this utility model are as follows:

[0017] 1. The plasticizing section on the extrusion screw adopts a two-stage spiral blade design, which can improve the cross-mixing effect of materials and improve the plasticizing uniformity. The barrier section at the rear end of the plasticizing section can effectively prevent incompletely plasticized materials from being fully plasticized, allowing them to continue to be heated inside the screw barrel until fully plasticized before being output, thereby improving the plasticizing effect. The mixing section, composed of multiple spiral-arranged mixing blocks with different trajectories, allows the materials to be sheared and mixed in the mixing section, ensuring that the components are mixed more evenly in the materials. This design also helps to reduce air bubbles and voids in the materials, making the foamed core layer more uniform and delicate, thereby improving the stability of the quality of the intermediate foamed core layer.

[0018] 2. The extrusion barrel is equipped with independent heat exchange channels corresponding to each section of the extrusion screw. The heat exchange channels are controlled by heat transfer oil, which effectively improves the stability of temperature control. In addition, the independent heat exchange spiral channels of each section can shorten the flow path of the heat transfer oil, improve the temperature difference of the heat transfer oil, and further maintain the stability of temperature control inside the barrel. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0020] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0021] like Figure 1 As shown, the present invention discloses an extrusion cylinder for the middle foam core layer of a PP three-layer co-extruded foamed sheet, comprising a cylinder body 1 and an extrusion screw 2 located inside the cylinder body 1. One end of the cylinder body 1 has a feed port, and the other end of the cylinder body 1 has an extrusion port. The extrusion screw 2 is provided with a compression section 21, a plasticizing section 22, a barrier section 23 and a mixing section 24 in sequence along the direction from the feed port to the extrusion port of the cylinder body 1.

[0022] The compression section 21 is provided with a first spiral blade mounted on the extrusion screw 2;

[0023] The plasticizing section 22 is equipped with a second spiral blade that follows two different trajectories on the extrusion screw 2;

[0024] Multiple spaced spiral barrier grooves are formed on the surface of barrier section 23;

[0025] The mixing section 24 is equipped with multiple mixing blocks, which are rectangular or rhomboid protrusions, etc. The multiple mixing blocks are spirally spaced and staggered in axial position.

[0026] In this invention, the compression section 21 is responsible for material conveying and compression; the plasticizing section 22 is responsible for material extrusion and plasticizing. The two second helical blades can improve the cross-mixing effect and enhance the uniformity of plasticizing. In addition, the two second helical blades on the plasticizing section 22 have different pitches. The advantage of this design is that it allows for sufficient cross-mixing between materials, reduces air and bubbles in the material, and improves the homogeneity of the material.

[0027] The barrier section 23 of this invention can effectively prevent materials that are not fully plasticized from being extruded, allowing them to continue to be heated inside the screw barrel until they are fully plasticized, resulting in a better plasticization effect.

[0028] The material undergoes shearing and thorough mixing in the mixing section 24, ensuring that the components are mixed more evenly. This design also helps to reduce air bubbles and voids in the material, making the foamed core layer more uniform and delicate, thereby improving the stability of the quality of the foamed core layer.

[0029] The cylinder wall of cylinder 1 is equipped with independent heat exchange spiral channels 25 corresponding to the compression section 21, plasticizing section 22, barrier section 23, and mixing section 24, respectively. Heat transfer oil circulates within each heat exchange spiral channel 25. The heat transfer oil temperature is controlled within the heat exchange spiral channels, effectively improving the stability of temperature control. Furthermore, the independent heat exchange spiral channels in each section can achieve different temperature controls. To further improve temperature control stability, each heat exchange spiral channel can be designed as a double spiral channel.

[0030] Barrier segment 23 is designed as a two-section barrier structure to improve the barrier's effectiveness.

[0031] The specific embodiments of this utility model have been described above. However, those skilled in the art should understand that this is only an example. Those skilled in the art can make various changes or modifications to this embodiment without departing from the principle and essence of this utility model, but all such changes and modifications fall within the protection scope of this utility model.

Claims

1. A PP three-layer co-extruded foamed sheet intermediate foam core layer extrusion cylinder, comprising a cylinder body and an extrusion screw located inside the cylinder body, wherein one end of the cylinder body has a feed port and the other end of the cylinder body has an extrusion port, characterized in that: The extrusion screw is provided with a compression section, a plasticizing section, a barrier section and a mixing section in sequence along the direction from the feed inlet to the extrusion outlet of the barrel; The compression section is provided with a first spiral blade mounted on the extrusion screw; The plasticizing section is equipped with a second spiral blade that follows two different trajectories on the extrusion screw; The surface of the barrier section has multiple spaced spiral barrier grooves. The mixing section is provided with multiple mixing blocks, which are spirally spaced and staggered in axial position. The cylinder wall has independent heat exchange spiral channels corresponding to the compression section, plasticizing section, barrier section and mixing section, and heat transfer oil circulates in each heat exchange spiral channel.

2. The extrusion cylinder for the intermediate foam core layer of a PP three-layer co-extruded foamed sheet according to claim 1, characterized in that: The mixing block is a rectangular or rhomboid protrusion.

3. The extrusion cylinder for the intermediate foam core layer of a PP three-layer co-extruded foamed sheet according to claim 1, characterized in that: The barrier segment is a two-section barrier structure.

4. The extrusion cylinder for the intermediate foam core layer of a PP three-layer co-extruded foamed sheet according to claim 1, characterized in that: The two second helical blades on the plasticizing section have different pitches.

5. The extrusion cylinder for the intermediate foam core layer of a PP three-layer co-extruded foamed sheet according to claim 1, characterized in that: The heat exchange spiral channel is a double spiral channel.

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