Plastic foaming sheet extruder for supercritical carbon dioxide and / or nitrogen

Abstract

The utility model relates to a supercritical carbon dioxide and / or nitrogen plastic foaming sheet extruder which comprises a hopper, an electric control system, a gas injection device, a machine head mold and a machine barrel, a rotatable screw rod is arranged in the machine barrel, the screw rod is in transmission connection with a speed reducer, the speed reducer is arranged at one end of the machine barrel, the machine head mold is arranged at the other end of the machine barrel, and the machine head mold is arranged in the machine barrel. A feeding hole and a gas inlet are formed in the side wall of the machine barrel, the hopper is communicated with the feeding hole through a pipeline, the gas injection device is communicated with the gas inlet through a pipeline, the gas injection device injects supercritical carbon dioxide and / or nitrogen into the machine barrel, a spiral groove is formed in the inner wall of the machine barrel, and the electric control system is electrically connected with the gas injection device. The spiral grooves are formed in the inner wall of the machine barrel, so that friction force between raw materials and the inner wall of the machine barrel is increased, the raw materials are not prone to slipping in the conveying process, the conveying effect of the materials is improved, and the materials are stably and evenly conveyed.

Description

Technical Field

[0001] The utility model relates to the technical field of new materials, in particular to a plastic foaming sheet extruder of supercritical carbon dioxide and / or nitrogen. Background Art

[0002] At present, the equipment used in the market to produce plastic foam sheets is a conventional extruder. When producing plastic foam sheets, chemical foaming agents are generally used, which will leave chemical harmful substances, harm the environment, and cannot be recycled. If a fluorine series of physical foaming agents, such as Freon, is used, it will cause environmental pollution and damage the ozone layer; using foaming agents such as butane and liquefied gas will be flammable and explosive, and highly dangerous. In order to solve the above problems, carbon dioxide is often used as a foaming agent for foaming. When in use, the material enters the screw barrel, and the screw in the screw barrel rotates to achieve the function of conveying the material. Because the inner wall of the screw barrel is smooth, the material and the inner wall of the screw barrel are prone to relative sliding during the conveying process, affecting the material conveying efficiency. Utility Model Content

[0003] In order to solve the above technical problems, the utility model provides a plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen.

[0004] The utility model solves the above-mentioned technical problem through the following technical scheme: a supercritical carbon dioxide and / or nitrogen plastic foam sheet extruder, comprising a hopper, an electronic control system, a gas injection device, a die mold and a barrel, wherein a rotatable screw is arranged in the barrel, the screw is transmission-connected to a reducer, the reducer is mounted at one end of the barrel, the die mold is mounted at the other end of the barrel, a feed port and an air inlet are arranged on the side wall of the barrel, the hopper is connected to the feed port through a pipeline, the gas injection device is connected to the air inlet through a pipeline, the electronic control system is electrically connected to the gas injection device, and a spiral groove is arranged on the inner wall of the barrel.

[0005] On the basis of the above technical solution, the present invention can also make the following improvements to the above technical solution:

[0006] Preferably, the cross-section of the spiral groove is triangular or rectangular.

[0007] Preferably, the spiral groove extends along the length direction of the barrel.

[0008] Preferably, the depth of the spiral groove gradually becomes shallower from the feed inlet toward the die head mold.

[0009] Preferably, the length of the spiral groove is 600mm-700mm.

[0010] Preferably, the depth of the spiral groove below the feed port is 3.5 mm-4 mm.

[0011] Preferably, the screw rod is provided with a plurality of spirally arranged protrusions, and grooves are provided between adjacent protrusions in each circle.

[0012] Preferably, an air inlet groove is provided on the screw, the air inlet groove is located below the air inlet, the air inlet groove is arranged in the middle of two adjacent circles of protrusions, and the air inlet groove is arranged in a ring shape along the screw.

[0013] Preferably, the groove is arranged obliquely, and the inclination angle of the groove is the same as the inclination angle of the protrusion.

[0014] Preferably, it further comprises a mixer, the mixer is connected to the hopper through a pipeline, and the mixer is electrically connected to the electric control system.

[0015] The beneficial effects of the utility model are as follows: by arranging the spiral groove on the inner wall of the barrel, the friction between the raw material and the inner wall of the barrel is increased, so that the raw material is not easy to slip during the conveying process, the conveying effect of the material is improved, and the material is conveyed stably and evenly; under the condition of the same number of screw revolutions, the feed amount of the structure is increased by 3.5%-5% compared with the barrel with a smooth inner wall; by arranging the air inlet groove in the middle of two adjacent circles of protrusions, the carbon dioxide and / or nitrogen entering the air inlet groove quickly flows to the grooves on both sides, so that the carbon dioxide gas and / or nitrogen are mixed with the raw material more evenly, the plastic foaming is delicate and even, the surface is smooth, and the product quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen of the utility model;

[0017] Figure 2 It is a partial structural schematic diagram of the screw rod of the utility model;

[0018] Figure 3 It is a partial cross-sectional schematic diagram of the barrel of the utility model.

[0019] The accompanying drawings are marked as follows: 1. reducer; 2. mixer; 3. hopper; 4. screw; 4.1. protrusion; 4.2. groove; 4.3. air inlet groove; 5. electronic control system; 6. gas injection device; 7. head mold; 8. barrel; 8.1. spiral groove; 8.2. feed port; 8.3. air inlet. DETAILED DESCRIPTION

[0020] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0021] like Figures 1 to 3 As shown, the utility model discloses a supercritical carbon dioxide and / or nitrogen plastic foam sheet extruder, comprising a hopper 3, an electronic control system 5, a gas injection device 6, a die head mold 7 and a barrel 8, a rotatable screw 4 is arranged in the barrel 8, the screw 4 is connected to a reducer 1 in a transmission manner, the reducer 1 is connected to a transmission motor, the transmission motor is electrically connected to the electronic control system 5, so as to drive the screw 4 to rotate, the reducer 1 is installed at one end of the barrel 8, the die head mold 7 is installed at the other end of the barrel 8, and can be replaced according to the use requirements. Different die head molds 7 improve versatility and reduce processing costs. A feed port 8.2 and an air inlet 8.3 are provided on the side wall of the barrel 8. The hopper 3 is located at one end close to the reducer 1. The hopper 3 contains materials. The hopper 3 is connected to the feed port 8.2 through a pipeline. The gas injection device 6 is connected to the air inlet 8.3 through a pipeline. A spiral groove 8.1 is provided on the inner wall of the barrel 8. The electric control system 5 is electrically connected to the gas injection device 6. The electric control system 5 controls the gas injection device 6 to work as needed to ensure normal foaming. The gas injection device 6 can adopt existing technology, and the gas injection device 6 injects supercritical carbon dioxide and / or nitrogen into the barrel 8. The extruder uses carbon dioxide and / or nitrogen as a foaming agent to produce foamed sheets of materials such as PLA polylactic acid, polybutylene adipate / terephthalate PBAT, polyethylene PE, polystyrene PS, polypropylene PP, thermoplastic polyurethane elastomer TPU, ethylene-vinyl acetate copolymer EVA, polyethylene terephthalate PET, thermoplastic elastomer TPE, thermoplastic vulcanized rubber TPV, thermoplastic rubber TPR, etc.

[0022] In this embodiment, specifically, the cross section of the spiral groove 8.1 is triangular, and the triangle has strong structural stability, can withstand greater loads and pressures, and makes material transportation smoother.

[0023] Optionally, the cross section of the spiral groove 8.1 can be rectangular. A rectangular cross section can provide a larger effective space, thereby increasing the conveying capacity or accommodating more materials, further improving the conveying capacity of materials, and is simple to process and reduces processing costs.

[0024] The spiral groove 8.1 extends along the length direction of the barrel 8, so as to continuously convey the mixture of the material and the supercritical gas from the feed port 8.2 toward the die head mold 7, thereby ensuring the material conveying efficiency.

[0025] Furthermore, the depth of the spiral groove 8.1 gradually becomes shallower from the feed port 8.2 to the die head mold 7, and the depth of the spiral groove 8.1 below the feed port 8.2 is 3.5mm-4mm. The conveying amount of the material at the feed port 8.2 is increased to avoid the material from piling up and slipping at the feed port 8.2, ensuring that the material is evenly and smoothly conveyed to the die head mold 7, and ensuring fine and even foaming.

[0026] Furthermore, the length of the spiral groove 8.1 is 600 mm-700 mm, which ensures that the spiral groove 8.1 has a sufficient length, thereby improving the conveying effect of the material.

[0027] In this embodiment, the screw 4 is provided with a plurality of spirally arranged protrusions 4.1 along the length direction, and a groove 4.2 is provided between each circle of adjacent protrusions 4.1. The groove 4.2 guides the raw material and carbon dioxide and / or nitrogen, improves the uniformity of mixing the gas and the material, improves the foaming effect, and ensures a smooth surface of the sheet.

[0028] In this embodiment, specifically, the screw 4 is provided with an air inlet groove 4.3, which is located below the air inlet port 8.3, and is arranged in the middle of two adjacent circles of protrusions 4.1, and the air inlet groove 4.3 is arranged in an annular shape along the screw 4. The supercritical carbon dioxide and / or nitrogen introduced through the air inlet groove 4.3 can quickly enter the grooves 4.2 on both sides, and move to both sides along the grooves 4.2, further improving the uniformity of mixing the supercritical gas and the material, ensuring fine and uniform foaming, and ensuring product quality.

[0029] Furthermore, the groove 4.2 is inclined, and the inclination angle of the groove 4.2 is the same as the inclination angle of the protrusion 4.1, so that the carbon dioxide and / or nitrogen flow in the barrel 8 in a spiral manner, further improving the foaming effect and achieving uniform foaming.

[0030] The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen also includes a stirrer 2, which is connected to the hopper 3 through a pipeline, and the stirrer 2 is electrically connected to the electronic control system 5. The stirrer 2 stirs the material to ensure that the material is evenly mixed, so that the material in the hopper 3 can be smoothly transported to the barrel 8 to ensure the foaming quality.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plastic foam sheet extruder for supercritical carbon dioxide and / or nitrogen, characterized in that: The invention comprises a hopper (3), an electric control system (5), a gas injection device (6), a die head mold (7) and a barrel (8), wherein a rotatable screw (4) is arranged in the barrel (8), the screw (4) is transmission-connected to a reducer (1), the reducer (1) is mounted at one end of the barrel (8), the die head mold (7) is mounted at the other end of the barrel (8), a feed port (8.2) and an air inlet (8.3) are arranged on the side wall of the barrel (8), the hopper (3) is connected to the feed port (8.2) through a pipeline, the gas injection device (6) is connected to the air inlet (8.3) through a pipeline, the gas injection device (6) injects supercritical carbon dioxide and / or nitrogen into the barrel (8), the electric control system (5) is electrically connected to the gas injection device (6), and a spiral groove (8.1) is arranged on the inner wall of the barrel (8).

2. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 1, characterized in that, The cross section of the spiral groove (8.1) is triangular or rectangular.

3. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 1, characterized in that, The spiral groove (8.1) extends along the length direction of the barrel (8).

4. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 1, 2 or 3, characterized in that: The depth of the spiral groove (8.1) gradually becomes shallower in the direction from the feed port (8.2) to the die head mold (7).

5. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 3, characterized in that, The length of the spiral groove (8.1) is 600mm-700mm.

6. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 4, characterized in that: The depth of the spiral groove (8.1) below the feed port (8.2) is 3.5 mm to 4 mm.

7. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 1, characterized in that: The screw rod (4) is provided with a plurality of spirally arranged protrusions (4.1), and grooves (4.2) are provided between adjacent protrusions (4.1) in each circle.

8. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 7, characterized in that: The screw rod (4) is provided with an air inlet groove (4.3), the air inlet groove (4.3) is located below the air inlet port (8.3), the air inlet groove (4.3) is arranged in the middle of two adjacent circles of protrusions (4.1), and the air inlet groove (4.3) is arranged in a ring shape along the screw rod (4).

9. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 7 or 8, characterized in that, The groove (4.2) is arranged obliquely, and the inclination angle of the groove (4.2) is the same as the inclination angle of the protrusion (4.1).

10. The plastic foam sheet extruder of supercritical carbon dioxide and / or nitrogen according to claim 1, characterized in that: It also comprises a mixer (2), wherein the mixer (2) is connected to the hopper (3) through a pipeline, and the mixer (2) is electrically connected to the electric control system (5).

Images