Preparation device and method of eccentric pressurized carbon dioxide bead foaming material and application of eccentric pressurized carbon dioxide bead foaming material
Through the process of combining multi-stage high-pressure eccentric melt pump with variable diameter pipeline, the prior art trimming difficulties and consistency and uniformity challenges in preparing small-particle polymer bead foaming materials are solved, and efficient preparation of polymer bead foaming materials with excellent performance is achieved.
Patent Information
- Application Number
- CN202510097089.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-04-15
AI Technical Summary
Existing extrusion methods and batch kettle foaming techniques have difficulties in pelletizing and product consistency and uniformity challenges in preparing small-particle-sized polymer bead foaming materials.
The process of combining a multi-stage high-pressure eccentric melt pump with a variable diameter pipe is adopted to disperse the polymer fibers evenly in water through a fiber dispersion device, and the fibers are stretched into small melt droplets in the multi-stage high-pressure eccentric melt pump and variable diameter pipe using a tensile flow field, and the fibers are stretched into small melt droplets in combination with foaming gas diffusion to form polymer beads.
The preparation of polymer bead foaming materials with small product particle size, high closed cell ratio, good resilience, consistency and uniformity are achieved. They can replace hollow glass microbeads for the polymer filling market, and their mechanical properties can be improved by 10% or more.
Smart Images
Figure CN119820772A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of preparing polymer bead foaming materials, in particular to the preparation of continuous bead foaming materials, and specifically relates to a preparation device and method of eccentrically pressurized carbon dioxide bead foaming materials, and also relates to the application of the device and method. Background Art
[0002] Polymer bead foaming technology has made significant research progress in recent years, mainly focusing on the optimization and application of two major foaming processes: extrusion and kettle methods. Extrusion is widely used in the manufacture of polymer foam materials due to its efficient production capacity, but its high open porosity leads to poor product resilience, which limits its use in certain high-performance applications. Therefore, although the extrusion method can quickly produce foamed particles, its limitations in application areas have caused researchers to pay more attention to kettle foaming technology.
[0003] Kettle foaming has been more widely recognized in the market because it can produce foamed particles with a higher closed-cell rate. The advantage of this foaming method is that the foamed material produced has good resilience and strength, and is suitable for a wider range of industrial needs. Kettle foaming can be divided into aqueous method and anhydrous method. For crystalline materials, the aqueous method can effectively prevent adhesion between particles, thereby improving the quality and consistency of the product. However, as an intermittent production process, kettle foaming still faces challenges in product consistency and uniformity, especially in large-scale production. How to ensure that the performance of each batch of products is relatively consistent has become an important research direction.
[0004] In addition, the products produced by the extrusion method and the kettle method usually have a large particle size, and there is a problem of difficulty in pelletizing in the preparation of small-particle polymer bead foam materials, especially polymer microbeads (particle size is usually 0.2-0.5mm). However, due to its small particle size, the polymer foam microbead material is used for filling rubber, cement, etc., with the characteristics of light weight, vibration reduction and sound insulation, which can better meet the application needs of the polymer filling market and is unmatched by ordinary fillers.
[0005] Based on this, in view of the defects of extrusion method and intermittent kettle foaming, an improved preparation device and method of polymer bead foaming material is provided, which has both the continuity of extruded bead foaming and the high closed-cell rate characteristics of water kettle bead foaming, and the preparation of polymer bead foaming material with small particle size has important practical significance and is also a technical problem that needs to be solved urgently. Summary of the invention
[0006] One of the purposes of the present invention is to provide a device for preparing an eccentrically pressurized carbon dioxide bead foaming material with small product particle size, high closed cell rate, good resilience, good consistency and uniformity.
[0007] The second object of the present invention is to provide a method for preparing an eccentrically pressurized carbon dioxide bead foam material with small product particle size, high closed cell rate, good resilience, good consistency and uniformity.
[0008] The third object of the present invention is to provide an eccentrically pressurized carbon dioxide bead foaming material with small particle size, high closed cell rate, good resilience, good consistency and uniformity.
[0009] The technical solution adopted by the present invention to achieve one of the purposes is: to provide a preparation device of an eccentric pressurized carbon dioxide bead foaming material, comprising: a fiber dispersion device, a multi-stage high-pressure eccentric melt pump, a variable diameter pipeline, a control valve, a gas storage tank and a booster pump; The multi-stage high-pressure eccentric melt pump comprises a plurality of high-pressure eccentric melt pumps connected in series; adjacent high-pressure eccentric melt pumps are connected through a reducing pipe; the reducing pipe is trumpet-shaped, the large-mouth end of the reducing pipe is connected to the material outlet of the previous stage high-pressure eccentric melt pump, and the small-mouth end is connected to the material inlet of the next stage high-pressure eccentric melt pump; The material outlet of the fiber dispersion equipment is connected to the material inlet of the first-stage high-pressure eccentric melt pump; the gas storage tank is provided with foaming gas, and the foaming gas is pressurized by the booster pump and then passed into the second-stage high-pressure eccentric melt pump; the material outlet of the final-stage high-pressure eccentric melt pump is connected to the control valve through a reducing pipe; the mixed material is sprayed out at the outlet of the control valve, the pressure is released and foamed.
[0010] The overall idea and inventive principle of the present invention are as follows: The invention provides a preparation device for a polymer continuous bead foaming material. The preparation device continuously prepares polymer foaming beads by combining a multi-stage eccentric melt pump with a variable diameter pipeline, using polymer fibers as a matrix, foamable gas as a foaming agent, and water as a dispersion medium.
[0011] In the preparation device provided by the present invention, the polymer fiber is firstly dispersed uniformly in water by using a fiber dispersing device, and then the water and fiber mixture is pushed forward in a variable diameter pipe by a multi-stage eccentric melt pump connected in series. Under the action of temperature and the eccentric melt pump, each fiber is stretched into a plurality of spherical droplets under the action of the stretching field, and the foamable gas of a certain pressure introduced into the multi-stage eccentric melt pump and the variable diameter pipe will diffuse into the small droplets in the process of mixing and conveying with the material. A control valve is set at the end of the final variable diameter pipe, and the material is continuously ejected by opening the control valve to obtain a polymer bead foam material. In addition, due to the use of a continuous foaming process, the polymer bead foam material obtained by the present invention not only has a higher closed-cell rate, better uniformity and consistency, but also has a smaller particle size. In some preferred embodiments, the particle size of the product polymer microbeads is controlled within the range of 0.2-0.5 mm.
[0012] Furthermore, the fiber dispersing device is a pulp beater, which is used to disperse the fibrous material in water.
[0013] Furthermore, the control valve is a needle valve or a ball valve.
[0014] Furthermore, the foaming gas in the gas storage tank includes one or a combination of carbon dioxide and nitrogen; the foaming gas is pressurized to 2-8 MPa by a booster pump and then enters a secondary high-pressure eccentric melt pump.
[0015] Furthermore, it has been found through research that the diameter size and total length of the variable diameter pipe can affect the particle size of the polymer foam beads. In the present invention, the diameter of the large end of the variable diameter pipe is controlled to be 10-20 cm, the diameter of the small end is 3-6 cm, and the total length of the variable diameter pipe is 20-40 meters, which is conducive to obtaining products with a particle size in the range of 0.2-0.5 mm.
[0016] Furthermore, the variable diameter pipe is a pressure-resistant stainless steel seamless pipe, and the pressure resistance level is 5MPa higher than the normal foaming pressure. Preferably, using a pipe with a pressure resistance level of 25MPa as a variable diameter pipe can meet the foaming requirements of all polymers.
[0017] Furthermore, the number of the high-pressure eccentric melt pumps in the multi-stage high-pressure eccentric melt pump is 3-6; and the reaction temperature of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe is 130-180°C.
[0018] Preferably, the gap on the small gap side of the multi-stage high-pressure eccentric melt pump used in the multi-stage high-pressure eccentric melt pump is 0.1-0.15mm, the gap on the large gap side is 0.5-1.0mm, the melt pump speed is steplessly adjustable from 0 to 500 rpm, and the number of multi-stage high-pressure eccentric melt pumps is not less than 2, preferably 5.
[0019] In the present invention, through reasonable valve body control, pipeline structure design and reaction temperature setting, the material is continuously dispersed into particles with smaller particle size under the action of the stretching flow field during the transportation process of the multi-stage eccentric melt pump and the variable diameter pipeline, and foamed at the ideal pressure and temperature at the control valve at the end. The preparation device provided by the present invention is conducive to ensuring the quality of the foamed product, thereby obtaining an environmentally friendly and high-performance polymer bead foaming material.
[0020] The technical solution adopted by the present invention to achieve the second purpose is: to provide a method for preparing an eccentrically pressurized carbon dioxide bead foamed material according to the preparation device described in one of the purposes of the present invention, comprising the following steps: S1. Prepare polymer fibers by mixing polymer particles and a nucleating agent, mix the polymer fibers with water, add a surfactant and an inorganic isolating agent, and disperse the polymer fibers in a fiber dispersion device; S2, the dispersed polymer fibers are pumped out from the first-stage high-pressure eccentric melt pump and enter the second-stage high-pressure eccentric melt pump through the first reducing pipe; S3, injecting a foaming gas with a pressure of 2-8 MPa into the second-stage high-pressure eccentric melt pump through a booster pump, setting the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, and the mixed material containing the high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipe. Under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, the polymer fibers in the mixed material are continuously stretched and broken into smaller particles; S4, the mixed material enters the final high-pressure eccentric melt pump and reaches the control valve through the final reducer pipe; the control valve is opened, the mixed material is sprayed out to release the pressure, and the polymer foams immediately to obtain polymer foam beads.
[0021] Furthermore, in step S1, the polymer of the polymer particles includes one or more combinations of polypropylene, polyethylene, polylactic acid, polyphenylene ether, polystyrene, and thermoplastic polyurethane; the nucleating agent includes one or more combinations of kaolin, talc, zinc borate, polytetrafluoroethylene, nano-calcium carbonate, and clay.
[0022] Furthermore, the surfactant includes a combination of one or more of sodium dodecylbenzene sulfate, sodium dodecylbenzene sulfonate, and Tween 80; the inorganic isolation agent includes a combination of one or more of kaolin, talc, nano calcium carbonate, and clay.
[0023] Preferably, in step S1, the mass ratio of water, surfactant and inorganic isolation agent is 500:(3-5):(0.5-1.5).
[0024] Furthermore, in step S1, polymer fibers are prepared by extrusion drawing; the polymer fibers have a diameter of 0.08-0.5 mm and a length of 5-20 mm. Polymer fibers of this size are conducive to the breakage of the fiber filaments under the action of the stretching field; preferably, the polymer fibers have a diameter of 0.08-0.2 mm.
[0025] Furthermore, the mass ratio of the polymer fiber to water is 1:(10-20), and the dispersion temperature in the fiber dispersion device is 50-80°C.
[0026] Furthermore, in step S2, the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe is 130-180°C.
[0027] Furthermore, in step S4, the foamable gas in the polymer particles ejected at high pressure from the control valve outlet generates thermodynamic instability under normal pressure, and this instability causes the dissolved foamable gas to escape from the polymer matrix and form bubble nuclei, which continue to grow and merge to eventually produce polymer foam beads.
[0028] Furthermore, after step S4, the method further includes: screening and drying the polymer foam beads.
[0029] The technical solution adopted by the present invention to achieve the third purpose is: to provide an eccentrically pressurized carbon dioxide bead foaming material, which is prepared by the preparation device according to one of the purposes of the present invention or the preparation method according to the second purpose of the present invention.
[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a preparation device for eccentric pressurized carbon dioxide bead foaming material, which continuously prepares polymer foaming beads by combining a multi-stage high-pressure eccentric melt pump with a variable diameter pipe, using polymer fibers as a matrix, foamable gas as a foaming agent, and water as a dispersion medium. The present invention first uses a fiber dispersion device to evenly disperse the polymer fibers in water, and then pushes the water and fiber mixture forward in the variable diameter pipe by connecting a multi-stage eccentric melt pump in series. Under the action of temperature and the eccentric melt pump, each fiber is stretched into a plurality of spherical droplets under the action of the stretching field. The foamable gas of a certain pressure introduced into the multi-stage eccentric melt pump and the variable diameter pipe will diffuse into the small droplets during the process of mixing and conveying with the material. A control valve is set at the end of the final variable diameter pipe. By opening the control valve, the material is continuously ejected and the polymer bead foaming material is obtained.
[0031] (2) The present invention provides a method for preparing an eccentrically pressurized carbon dioxide bead foam material. Through reasonable valve body control, pipeline design and temperature setting, the polymer is dispersed into small particles in the kettle. During foaming, the ideal pressure and temperature are used, which is beneficial to ensure the quality of the foamed product, thereby obtaining an environmentally friendly and high-performance polymer bead foam material.
[0032] (3) The polymer bead foam material prepared by the present invention not only has a higher closed-cell rate, better uniformity and consistency, but also has a smaller particle size, and the particle size of the product can be controlled within the range of 0.2-0.5 mm. The small-particle-size polymer bead foam material prepared by the present invention can replace hollow glass microspheres for use in the polymer filling market and meet the application needs of the polymer filling market. At the same time, compared with the foaming molding process of large-size polymer beads (particle size 2-4 mm) currently on the market, the mechanical properties of the product can be improved by 10% or more. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 A schematic structural diagram of a device for preparing an eccentrically pressurized carbon dioxide bead foaming material provided by the present invention; Figure 2 The schematic diagram of the principle of a method for preparing an eccentric pressurized carbon dioxide bead foam material provided by the present invention; wherein: Figure 2 (a) is a schematic diagram of material changes in a high-pressure eccentric melt pump; Figure 2 (b) is a schematic diagram of material changes in a variable diameter pipeline; Figure 2 (c) is a schematic diagram of the final stage reducer pipe and control valve; Among them, 1-fiber dispersion equipment; 2-first stage high-pressure eccentric melt pump; 3-first reducer pipe; 4-second stage high-pressure eccentric melt pump; 5-second reducer pipe; 6-final stage high-pressure eccentric melt pump; 7-final stage reducer pipe; 8-control valve; 9-gas storage tank; 10-boosting pump. DETAILED DESCRIPTION
[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0035] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention. The figures only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may be more complicated.
[0036] like Figure 1 As shown, an embodiment of the present invention provides a device for preparing an eccentrically pressurized carbon dioxide bead foam material, comprising: a fiber dispersion device 1, a multi-stage high-pressure eccentric melt pump, a variable diameter pipeline, a control valve 8, a gas storage tank 9 and a booster pump 10.
[0037] The multi-stage high-pressure eccentric melt pump comprises 6 high-pressure eccentric melt pumps connected in series ( Figure 1"..." between the middle label numbers 4-6 indicates multiple high-temperature eccentric melt pumps connected in series in the middle); the gap on the small gap side of the high-pressure eccentric melt pump adopted by the multi-stage high-pressure eccentric melt pump is 0.1-0.15mm, the gap on the large gap side is 0.5-1.0mm, and the melt pump speed is steplessly adjustable from 0 to 500 rpm; adjacent high-pressure eccentric melt pumps are connected through a reducing pipe; the reducing pipe is trumpet-shaped, the large end of the reducing pipe is connected to the material outlet of the upper-stage high-pressure eccentric melt pump, and the small end is connected to the material inlet of the next-stage high-pressure eccentric melt pump; in an embodiment of the present invention, the large end diameter of the reducing pipe is 15cm, and the small end diameter is 5cm; the total length of the reducing pipe is 30 meters.
[0038] In an embodiment of the present invention, the fiber dispersing device 1 is a pulp beater, which is used to disperse polymer fibers in water. The material outlet of the fiber dispersing device 1 is connected to the material inlet of the first-stage high-pressure eccentric melt pump 2; the gas storage tank 9 is provided with a foaming gas, and the foaming gas includes one or a combination of carbon dioxide and nitrogen; the foaming gas is pressurized to 2-8MPa by the booster pump 10 and enters the second-stage high-pressure eccentric melt pump 4; the material outlet of the final-stage high-pressure eccentric melt pump 6 is connected to the control valve 8 through a variable diameter pipe, and the control valve 8 is a needle valve or a ball valve; the mixed material is sprayed out at the outlet of the control valve 7, the pressure is released and foamed.
[0039] The present invention also provides a method for preparing an eccentric pressurized carbon dioxide bead foam material. Based on the above preparation device, the reaction principle is as follows: Figure 2 : like Figure 2 As shown in (a), the material is transported in the high-pressure eccentric melt pump along the path of AG. The polymer fiber enters the high-pressure eccentric melt pump from point A (material inlet) and is stretched when it reaches point B. It is stretched to the thinnest when it reaches point D. When it reaches point EF, the filaments relax, and a thin neck appears at the weak point of the filaments. At point G (material outlet), it breaks into multiple molten droplets.
[0040] like Figure 2 As shown in (b), the large end of the variable-diameter high-pressure pipe is connected to the material outlet (point G) of the previous high-pressure eccentric melt pump, and the small end is connected to the material inlet (point A) of the next high-pressure eccentric melt pump. In this trumpet-shaped pipe, the plastic material forms a stretching gradient field when flowing in it, which is beneficial to further break and homogenize the material formed at point G of the previous high-pressure eccentric melt pump.
[0041] like Figure 2 As shown in (c), a control valve is installed at the small end of the final reducer pipe. The opening size of the control valve is adjusted according to the inlet pressure and the amount of material to control the discharge speed of the foamed particles and achieve continuous foaming.
[0042] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.
[0043] Example 1 This embodiment provides a method for preparing a polypropylene bead foam material, comprising the following steps: Step 1: 100 parts of polypropylene and 0.5 parts of zinc borate are drawn into 0.1 mm diameter polypropylene staple fibers in a spinning extruder and cut into 10 mm long polypropylene staple fibers; 500 parts of a mixture of polypropylene fiber and water at a ratio of 1:10, 3 parts of kaolin, and 1 part of sodium dodecylbenzene sulfonate are added into a pulping machine, and pulped at 65 ° C for 10 minutes to ensure that the fibers are evenly dispersed.
[0044] Step 2: After being drawn out by the first-stage high-pressure eccentric melt pump 2 , the dispersed polypropylene staple fibers enter the second-stage high-pressure eccentric melt pump 4 through the first reducing pipe 3 .
[0045] Step 3: Inject CO2 gas with a pressure of 2.5 MPa into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10, set the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe to 145°C, and the mixed material containing high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipe. Under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, the polymer fibers in the mixed material are continuously stretched and broken into smaller particles.
[0046] Step 4: The mixed material enters the final high-pressure eccentric melt pump 6 and reaches the control valve 8 through the final reducing pipe 7; the control valve 8 is opened, and the mixed material is ejected due to the sudden pressure release, and the polymer foams immediately to obtain foamed beads with a diameter of 0.2 mm and a density of 0.065 g / cm 3 Polypropylene bead foam material.
[0047] Example 2 This embodiment provides a method for preparing a polylactic acid bead foam material, comprising the following steps: Step 1: 100 parts of polylactic acid and 0.5 parts of nano-calcium carbonate are drawn into polylactic acid short filaments with a diameter of 0.2 mm in a spinning extruder and cut into 10 mm long polylactic acid short filaments; 500 parts of a mixture of polylactic acid fiber and water, 3 parts of kaolin, and 1 part of sodium dodecylbenzene sulfonate are added to a pulper at a ratio of 1:10, and pulped at 55 ° C for 20 minutes to ensure that the fibers are evenly dispersed.
[0048] Step 2: After the dispersed polylactic acid short filaments are drawn out by the first-stage high-pressure eccentric melt pump 2 , they enter the second-stage high-pressure eccentric melt pump 4 through the first reducing pipe 3 .
[0049] Step 3: Inject CO2 gas with a pressure of 3 MPa into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10, set the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe to 145°C, and the mixed material containing high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipe. Under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, the polymer fibers in the mixed material are continuously stretched and broken into smaller particles.
[0050] Step 4: The mixed material enters the final high-pressure eccentric melt pump 6 and reaches the control valve 8 through the final reducing pipe 7; the control valve 8 is opened, and the mixed material is ejected due to the sudden pressure release, and the polymer foams immediately to obtain foamed beads with a diameter of 0.4 mm and a density of 0.12 g / cm 3 Polylactic acid bead foam material.
[0051] Example 3 This embodiment provides a method for preparing a polyethylene bead foam material, comprising the following steps: Step 1: 100 parts of polyethylene and 0.5 parts of kaolin are drawn into polyethylene staples with a diameter of 0.5 mm in a spinning extruder and cut into 12 mm long polyethylene staples; 500 parts of a mixture of polyethylene staples and water at a ratio of 1:10, 3 parts of kaolin and 1 part of sodium dodecylbenzene sulfonate are added into a pulping machine and pulped at 50 °C for 15 minutes to ensure that the fibers are evenly dispersed.
[0052] Step 2: After the dispersed polyethylene short filaments are drawn out by the first-stage high-pressure eccentric melt pump 2 , they enter the second-stage high-pressure eccentric melt pump 4 through the first reducing pipe 3 .
[0053] Step 3: Inject CO2 gas with a pressure of 2.8 MPa into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10, set the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe to 135°C, and the mixed material containing high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipe. Under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, the polymer fibers in the mixed material are continuously stretched and broken into smaller particles.
[0054] Step 4: The mixed material enters the final high-pressure eccentric melt pump 6 and reaches the control valve 8 through the final reducing pipe 7; the control valve 8 is opened, and the mixed material is ejected due to the sudden pressure release, and the polymer foams immediately to obtain foamed beads with a diameter of 1.5 mm and a density of 0.08 g / cm 3 Polyethylene bead foam material.
[0055] Example 4 This embodiment provides a method for preparing a modified polyphenylene ether bead foam material, comprising the following steps: Step 1: 70 parts of polyphenylene ether, 30 parts of polystyrene and 0.5 parts of kaolin are drawn into 0.3 mm in diameter by a spinning extruder and cut into 12 mm long modified polyphenylene ether short filaments; 500 parts of a mixture of modified polyphenylene ether and water at a ratio of 1:10, 3 parts of kaolin and 1 part of sodium dodecylbenzene sulfonate are added into a pulper and pulped at 80 °C for 15 minutes to ensure that the fibers are evenly dispersed.
[0056] Step 2: After the dispersed modified polyphenylene ether short filaments are drawn out from the first-stage high-pressure eccentric melt pump 2, they enter the second-stage high-pressure eccentric melt pump 4 through the first reducing pipe 3; Step 3: CO2 gas with a pressure of 5 MPa is injected into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10, and the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline is set to 175° C. The mixed material containing high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline. The polymer fibers in the mixed material are continuously stretched and broken into smaller particles under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline; Step 4: The mixed material enters the final high-pressure eccentric melt pump 6 and reaches the control valve 8 through the final reducing pipe 7; the control valve 8 is opened, and the mixed material is ejected due to the sudden pressure release, and the polymer foams immediately to obtain foamed beads with a diameter of 1.0 mm and a density of 0.15 g / cm 3 Modified polyphenylene ether bead foam material.
[0057] Comparative Example 1 This comparative example provides a method for preparing a polypropylene bead foam material, comprising the following steps: Step 1: 100 parts of polypropylene and 0.5 parts of zinc borate are drawn into 0.08 mm in diameter through a spinning extruder and cut into 10 mm long polypropylene staple fibers; 500 parts of a mixture of polypropylene fibers and water at a ratio of 1:10, 3 parts of kaolin, and 1 part of sodium dodecylbenzene sulfonate are added into a pulping machine, and pulped at 65 °C for 10 minutes to ensure that the fibers are evenly dispersed.
[0058] Step 2: After the dispersed polypropylene staple fibers are pumped out by the first-stage high-pressure eccentric melt pump 2, they enter the second-stage high-pressure eccentric melt pump 4 through the first variable diameter pipe 3; Step 3: injecting CO2 gas with a pressure of 2.5 MPa into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10. In this comparative example, the 3rd to 6th stage high-pressure eccentric melt pumps are no longer provided. The second-stage high-pressure eccentric melt pump is directly connected to the control valve 8 through a reducing pipe, and the temperature of the reducing pipe is 145°C; Step 4: The material reaches the control valve 8 through the variable diameter pipe 7; the control valve 8 is opened, and due to the sudden pressure release, the mixed material is ejected and the pressure is released, and the polymer foams immediately to obtain foamed microspheres with a diameter of 0.1 mm and a density of 0.73 g / cm3 Polypropylene bead foam material.
[0059] Comparative Example 2 This comparative example provides a method for preparing a polypropylene bead foam material, comprising the following steps: Step 1: 100 parts of polypropylene and 0.5 parts of zinc borate are drawn into 0.1 mm diameter polypropylene staple fibers in a spinning extruder and cut into 10 mm long polypropylene staple fibers; 500 parts of a mixture of polypropylene fiber and water at a ratio of 1:10, 3 parts of kaolin, and 1 part of sodium dodecylbenzene sulfonate are added into a pulping machine, and pulped at 65 ° C for 10 minutes to ensure that the fibers are evenly dispersed.
[0060] Step 2: After the dispersed polypropylene staple fibers are pumped out by the first-stage high-pressure eccentric melt pump 2, they enter the second-stage high-pressure eccentric melt pump 4 through the first variable diameter pipe 3; Step 3: Inject CO2 gas with a pressure of 2.5MPa into the second-stage high-pressure eccentric melt pump 4 through the booster pump 10, set the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline to 145℃, and the mixed material containing high-pressure foaming gas is transported forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline. The polymer fibers in the mixed material are continuously stretched and broken into smaller particles under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipeline; after the particles are ejected from the open control valve 6, close the first control valve 6, and then close the beater 1 and the first-stage high-pressure eccentric melt pump 2. Maintain the pressure of 2.5MPa of CO2 gas in the pipe, the temperature is 145℃, and the heat and pressure are maintained for 35 minutes. Open the control valve 8. Due to the sudden pressure release, the mixed material is ejected and the pressure is released, and the polymer foams immediately to obtain foamed beads with a diameter of 1.12mm and a density of 0.135g / cm 3 Polypropylene bead foam material.
[0061] The main parameters and reaction conditions of the embodiments and comparative examples of the present invention are shown in Table 1 below.
[0062] Table 1
[0063] In the above table, the mixed solution used to prepare the fiber dispersion is composed of 500 parts of water, 3 parts of kaolin and 1 part of sodium alkylbenzene sulfonate by weight.
[0064] The relevant performance test results of the product polymer foam beads obtained in each embodiment and comparative example are shown in Table 2 below: Table 2
[0065] It can be seen from Table 2 above that The preparation device and preparation method of the embodiments 1-4 of the present invention adopt a combination of "multi-stage high-pressure eccentric melt pump + variable diameter pipeline", and the obtained polymer foam beads have the advantages of continuous foaming and uniform particle size after foaming. Comparative Example 1 does not add a multi-stage high-pressure eccentric melt pump, the polymer filaments are not easy to break into small particles, and the density of the product after foaming is large. Comparative Example 2 stops adding particles when the material just flows out of the control valve, and the equipment becomes a simulated intermittent kettle method, and the uniformity and batch consistency of the obtained product are poor.
[0066] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.
Claims
1. A device for preparing an eccentrically pressurized carbon dioxide bead foam material, characterized in that: include: Fiber dispersion equipment (1), a multi-stage high-pressure eccentric melt pump, a variable diameter pipeline, a control valve (8), a gas storage tank (9) and a booster pump (10); The multi-stage high-pressure eccentric melt pump comprises a plurality of high-pressure eccentric melt pumps connected in series; adjacent high-pressure eccentric melt pumps are connected through a reducing pipe; the reducing pipe is trumpet-shaped, the large-mouth end of the reducing pipe is connected to the material outlet of the previous stage high-pressure eccentric melt pump, and the small-mouth end is connected to the material inlet of the next stage high-pressure eccentric melt pump; The material outlet of the fiber dispersion device (1) is connected to the material inlet of the first-stage high-pressure eccentric melt pump (2); the gas storage tank (9) is provided with a foaming gas, and the foaming gas is pressurized by the booster pump (10) and then passed into the second-stage high-pressure eccentric melt pump (4); the material outlet of the final-stage high-pressure eccentric melt pump (6) is connected to the control valve (8) through a variable diameter pipe; the mixed material is sprayed out at the outlet of the control valve (7), the pressure is released and foamed.
2. The preparation device according to claim 1, characterized in that: The fiber dispersing device (1) is a pulp beater; the control valve (8) is a needle valve or a ball valve.
3. The preparation device according to claim 1, characterized in that: The foaming gas in the gas storage tank (9) includes one of carbon dioxide and nitrogen or a combination of the two; the foaming gas is pressurized to 2-8 MPa by a booster pump (10) and then enters the secondary high-pressure eccentric melt pump (4).
4. The preparation device according to claim 1, characterized in that: The diameter of the large end of the variable diameter pipe is 10-20 cm, and the diameter of the small end is 3-6 cm; the total length of the variable diameter pipe is 20-40 meters.
5. The preparation device according to claim 1, characterized in that: The number of the multi-stage high-pressure eccentric melt pumps is 3-6; the reaction temperature of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe is 130-180°C.
6. A method for preparing an eccentrically pressurized carbon dioxide bead foamed material according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, preparing polymer fibers by mixing polymer particles and a nucleating agent, mixing the polymer fibers with water, adding a surfactant and an inorganic isolating agent, and dispersing the polymer fibers in a fiber dispersing device (1); S2, the dispersed polymer fibers are pumped out by the first-stage high-pressure eccentric melt pump (2), and enter the second-stage high-pressure eccentric melt pump (4) through the first variable diameter pipe (3); S3, injecting a foaming gas with a pressure of 2-8 MPa into the second-stage high-pressure eccentric melt pump (4) through the booster pump (10), setting the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, and conveying the mixed material containing the high-pressure foaming gas forward along the multi-stage high-pressure eccentric melt pump and the variable diameter pipe. Under the action of the multi-stage high-pressure eccentric melt pump and the variable diameter pipe, the polymer fibers in the mixed material are continuously stretched and broken into smaller particles; S4, the mixed material enters the final high-pressure eccentric melt pump (6), and reaches the control valve (8) through the final reducing pipe (7); the control valve (8) is opened, the mixed material is sprayed out to release the pressure, and the polymer is foamed immediately to obtain polymer foam beads.
7. The preparation method according to claim 6, characterized in that: In step S1, the polymer of the polymer particles includes one or more combinations of polypropylene, polyethylene, polylactic acid, polyphenylene ether, polystyrene, and thermoplastic polyurethane; the nucleating agent includes one or more combinations of kaolin, talc, zinc borate, polytetrafluoroethylene, nano calcium carbonate, and clay.
8. The preparation method according to claim 6, characterized in that: In step S1, polymer fibers are prepared by extrusion drawing; the diameter of the polymer fibers is 0.08-0.5 mm and the length is 5-20 mm; the mass ratio of the polymer fibers to water is 1:(10-20), and the dispersion temperature in the fiber dispersion device (1) is 50-80°C.
9. The preparation method according to claim 6, characterized in that: In step S2, the reaction temperature in the multi-stage high-pressure eccentric melt pump and the variable diameter pipe is 130-180°C.
10. An eccentrically pressurized carbon dioxide bead foaming material, characterized in that: The method is prepared by the device according to any one of claims 1 to 5 or the preparation method according to any one of claims 6 to 9.