CN112356373A - Continuous foaming method and continuous foaming device for polymer particles - Google Patents
Continuous foaming method and continuous foaming device for polymer particles Download PDFInfo
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- CN112356373A CN112356373A CN202011295566.3A CN202011295566A CN112356373A CN 112356373 A CN112356373 A CN 112356373A CN 202011295566 A CN202011295566 A CN 202011295566A CN 112356373 A CN112356373 A CN 112356373A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/3461—Making or treating expandable particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/3469—Cell or pore nucleation
- B29C44/348—Cell or pore nucleation by regulating the temperature and/or the pressure, e.g. suppression of foaming until the pressure is rapidly decreased
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
- B29C44/34—Auxiliary operations
- B29C44/60—Measuring, controlling or regulating
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- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
The invention discloses a continuous foaming method of polymer particles, which comprises the following steps: s1, conveying the suspension and the separant into a high-pressure and ultrahigh-pressure vessel for foaming and heating the polymer beads; s2, heating the mixed liquid of the suspension and the separant; s3, conveying the polymer particles, carbon dioxide and nitrogen mixed gas into a polymer bead foaming heating high-pressure-ultrahigh-pressure container successively or simultaneously; s4, swelling polymer particles and permeating mixed gas in a high-pressure and ultrahigh-pressure container for foaming and heating the polymer beads, and finally spraying the polymer particles from an upper foaming nozzle, wherein the polymer particles are expanded and foamed due to rapid pressure relief to form polymer foaming beads; s5, collecting polymer expanded beads; the invention also discloses a continuous foaming device for the polymer particles, and solves the technical problems of unstable production quality, poor uniformity and small foaming ratio of polymer foaming beads.
Description
Technical Field
The invention relates to the field of polymer particle foaming, in particular to a continuous foaming method and a continuous foaming device for polymer particles.
Background
The polymer foaming foam bead is a bead-shaped material which is prepared by foaming a polymer serving as a matrix and has a porous structure, then the polymer foaming bead is subjected to steam molding or bonding molding by using a molding device, so that the polymer foaming bead is mutually welded and processed into a foam product with a certain geometric structure, has the characteristics of firmness, light weight, energy absorption, shock resistance, heat insulation, heat preservation and the like, and is widely applied to the fields of packaging, buildings, transportation, sports equipment and the like.
Currently, polymer foam beads are mainly prepared by a kettle-pressure foaming method and an extrusion foaming method. The production process for preparing the polymer expanded beads by the kettle pressure foaming method is carried out in an intermittent mode, the control is relatively simple, but the production efficiency is low. The polymer foam beads prepared by the existing extrusion foaming method have the advantages of continuous forming, high production efficiency and good automation degree, but the preparation process is unstable, the pressure regulation range is small, the temperature control system is complex, the pressure relief rate in the extrusion foaming process is small and cannot be regulated and controlled, the uniformity of the foam holes of the foam beads is poor, the foaming ratio is small, and the opening ratio of the foam beads is large.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a continuous foaming method and a continuous foaming device for polymer particles, so as to solve the technical problems of unstable production quality of polymer foaming beads, poor uniformity of cells of the foaming beads, small foaming multiplying power and large opening rate of the foaming beads.
In order to achieve the above object, the present invention provides a continuous foaming method of polymer particles, comprising the steps of:
s1, conveying the suspension and the separant mixed solution at the temperature of 60-200 ℃ into a polymer bead foaming heating high-pressure-ultrahigh-pressure container, and filling the polymer bead foaming heating high-pressure-ultrahigh-pressure container with the suspension and the separant mixed solution; wherein the density of the selected suspension is greater than the density of the polymer particles, and the relative density of the suspension is 0.5-5.0;
s2, using a heating device to heat the suspension and the separant mixed liquid in the high-pressure and ultrahigh-pressure container for foaming of the polymer beads, and uniformly heating the whole to make the temperature in the high-pressure and ultrahigh-pressure container uniform and consistent, wherein the heating temperature is 60-350 ℃;
preferably, the temperature is controlled to be 5-150 ℃ below the melting point of the polymer;
s3, after the suspension and the separant are uniformly heated to a specified temperature, sequentially or simultaneously conveying polymer particles with the preheating temperature of 60-300 ℃ and carbon dioxide and nitrogen mixed gas with the temperature of 60-350 ℃ and the pressure of 0-50 MPa into a polymer bead foaming heating high-pressure-ultrahigh pressure container; the pressure of the high-pressure-ultrahigh-pressure container for foaming and heating the polymer beads can be freely adjusted along with the pressure of a gas conveying system, and the pressure adjusting range is 0-50 MPa;
s4, the polymer particles are swelled and permeated by the mixed gas in the high-pressure-ultrahigh pressure container for foaming and heating the polymer beads under the temperature of 60-350 ℃ and the pressure of 0-50 MPa, since the polymer particles have a lower relative density than the suspension, the polymer particles gradually move upward under the action of the suspension force for a period of 5 to 60 minutes and are finally continuously ejected from the upper foaming nozzle, the pressure relief rate of the foaming can be controlled by adjusting the width of the gap between the foaming nozzle and the pressure adjusting block arranged above the high-pressure and ultrahigh-pressure vessel heated by foaming the polymer beads, and the pressure in the high-pressure and ultrahigh-pressure vessel heated by foaming the polymer beads and the pressure of the foaming nozzle can be controlled by adjusting the pressure in the high-pressure and ultrahigh-pressure vessel, thereby controlling the pressure relief rate of the foaming nozzle, and the adjustment range of the gap width is 0.1-10.0 mm; the polymer particles expand and foam due to the rapid pressure relief, forming polymer foam beads;
s5, collecting the polymer expanded beads ejected from the expansion nozzle.
Preferably, the method further comprises the following steps:
s6, washing, drying and packaging the collected polymer expanded beads.
Preferably, the suspension is one or more of a talcum powder suspension, a calcium carbonate suspension or a barium sulfate suspension.
Preferably, the release agent is one or more of a mixture of an aqueous soap release agent, aqueous zinc stearate and aqueous calcium stearate, and a soap water release agent.
Preferably, the pressure of the polymer particles sprayed out of the foaming nozzle in the step S4 is controlled to be 0.5-15 MPa, and the pressure relief speed is 1-10000 MPa/S.
Compared with the prior art, the continuous foaming method of the polymer particles provided by the invention has the beneficial effects that:
(1) the method can realize the continuous sealed conveying of high polymer particle materials under high pressure, can ensure the continuous preparation of the foamed high polymer beads, and has the outstanding advantages of high production efficiency and low cost;
(2) because the pressure of the high-pressure-ultrahigh-pressure vessel for foaming and heating the polymer beads is derived from the pressure of the mixed gas of carbon dioxide and nitrogen in the technical scheme, the pressure of the high-pressure-ultrahigh-pressure vessel for foaming and heating the polymer beads can be freely adjusted along with the adjustment of the pressure of the mixed gas of carbon dioxide and nitrogen, and the pressure of the high-pressure-ultrahigh-pressure vessel for foaming and heating the polymer beads and the pressure of the foaming nozzle can be adjusted freely through the foaming nozzle with adjustable pressure relief rate arranged above the high-pressure-ultrahigh-pressure vessel for foaming and heating the polymer beads according to the; the technical scheme of the invention has wide pressure regulation range, the pressure can easily reach 50MPa, and the pressure of the high-pressure-ultrahigh-pressure container and the pressure of the foaming nozzle can be regulated according to the pressure requirement, so that the pressure relief rate of the foaming nozzle is controlled, and the defect that the pressure can not be regulated in the foaming process of an extruder is overcome; the pressure relief rate of a pressure system for continuously preparing the foamed high polymer foamed beads can be adjusted according to needs, the structure of the high polymer foamed particle product can be accurately regulated and controlled, the quality is better ensured, the defect that the process of the extrusion continuous foaming method is unstable is overcome, the pressure relief rate is low and cannot be regulated and controlled in the extrusion foaming process of an extruder, the uniformity of foam holes of the foamed beads is poor, the foaming multiplying power is low, and the opening rate of the foamed beads is high, so that the foaming process of the method has the advantages of being more stable, more reliable to control, more efficient to produce and low in cost;
(3) the technical scheme adopts a mode that a heating device uniformly heats the whole high-pressure-ultrahigh pressure container by foaming polymer beads, so that the temperature difference change of the whole temperature of the high-pressure-ultrahigh pressure container is less, the temperature of the whole temperature system is basically consistent, no temperature difference exists, the consistency of foaming quality is ensured, the unstable factor that the temperature difference is large when the foaming temperature of an extruder is changed from the melting temperature to the extrusion foaming temperature is overcome, the temperature change range of the extruder is generally reduced from the melting temperature (about 200 ℃) to the foaming temperature (about 100 ℃) in the extrusion foaming process of the extruder, and the temperature difference change is large;
(4) the high polymer expanded bead product prepared by the method has large expansion ratio, fine and uniform cell structure, and the closed cell rate is up to more than 90 percent, thereby overcoming the defect of low closed cell rate of an extrusion continuous foaming method.
In order to achieve the above object, the present invention further provides a continuous polymer particle foaming device, which comprises a bead foaming system, and a polymer particle conveying system, a gas conveying system and a liquid conveying system which are respectively communicated with the bead foaming system; the bead foaming system comprises a polymer bead foaming heating high-pressure-ultrahigh-pressure container, a foaming nozzle arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure container, a nozzle gap pressure adjusting block arranged above the foaming nozzle, a foaming bead collecting box arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure container, a foaming bead discharging port arranged on one side of the foaming bead collecting box, and a heating device for uniformly heating the whole polymer bead foaming heating high-pressure-ultrahigh-pressure container; the polymer particle conveying system comprises a polymer particle storage tank for storing polymer particles and a pressure conveyer communicated with the polymer particle storage tank; the pressure conveyer is used for quantitatively conveying polymer particles into a high-pressure-ultrahigh pressure vessel for foaming and heating the polymer beads; the liquid conveying system is used for conveying the suspension liquid and the separant mixed liquid at the temperature of 60-200 ℃ into a polymer bead foaming heating high-pressure-ultrahigh-pressure container; the gas conveying system is used for conveying the mixed gas of carbon dioxide and nitrogen with the temperature of 60-350 ℃ and the pressure of 0-50 MPa into the polymer bead foaming heating high-pressure-ultrahigh-pressure container.
Preferably, the suspension is one or more mixed suspension of talcum powder suspension, calcium carbonate suspension or barium sulfate suspension; the separant is one or more of aqueous soap separant, aqueous zinc stearate, aqueous calcium stearate and soap water separant.
Preferably, the liquid conveying system comprises a liquid storage tank for storing the suspension and the isolating agent, a liquid high-pressure pump communicated with the liquid storage tank, a liquid heater communicated with the liquid high-pressure pump, and a one-way valve communicated with the liquid heater, wherein the one-way valve is communicated with the high-pressure-ultrahigh pressure container for foaming and heating the polymer beads; the gas conveying system comprises a carbon dioxide storage tank for storing carbon dioxide, a nitrogen storage tank for storing nitrogen, a first high-pressure pump communicated with the carbon dioxide storage tank, a second high-pressure pump communicated with the nitrogen storage tank, and a gas heater respectively communicated with the first high-pressure pump and the second high-pressure pump, wherein the gas heater is communicated with the polymer bead foaming heating high-pressure-ultrahigh pressure container or the pressure conveyor.
Preferably, the pressure conveyer is a venturi tube, and the gas heater is communicated with the pressure conveyer.
Preferably, the pressure conveyer comprises a cylinder body communicated with the high-pressure and ultrahigh-pressure container for foaming and heating the polymer beads, a piston rod arranged in the cylinder body in sliding connection, and a driving cylinder for driving the piston rod to telescopically slide in the cylinder body; the piston rod is provided with a polymer particle storage cavity, when the piston rod is in a contraction state, the polymer particle storage cavity is communicated with the polymer particle storage tank, and when the piston rod is in an extension state, the polymer particle storage cavity is communicated with the polymer bead foaming heating high-pressure-ultrahigh-pressure container.
Compared with the prior art, the polymer particle continuous foaming device provided by the invention has the beneficial effects that:
(1) the device can realize the continuous sealed conveying of high polymer particle materials under high pressure, can ensure the continuous preparation of the foamed high polymer beads, and has the outstanding advantages of high production efficiency and low cost;
(2) by adopting the device, the pressure of the high-pressure and ultrahigh-pressure vessel for foaming and heating the polymer beads is derived from the pressure of the mixed gas of carbon dioxide and nitrogen, so that the pressure of the high-pressure and ultrahigh-pressure vessel for foaming and heating the polymer beads can be freely adjusted along with the adjustment of the pressure of the mixed gas of carbon dioxide and nitrogen, and the pressure of the high-pressure and ultrahigh-pressure vessel for foaming and heating the polymer beads and the pressure of the foaming nozzle can be adjusted freely through the foaming nozzle with adjustable pressure relief rate arranged above the high-pressure and ultrahigh-pressure vessel for foaming and heating the polymer beads; the pressure adjusting range of the technical scheme of the invention is wide, the pressure can easily reach 50MPa, and the pressure can be changed by adjusting the pressure of a high-pressure-ultrahigh-pressure container and the pressure of a foaming nozzle according to the pressure requirement, so that the pressure relief rate of the foaming nozzle is controlled, the defect that the pressure cannot be adjusted in the foaming process of an extruder is overcome, the pressure relief rate of a pressure system for continuously preparing the foaming high polymer foaming beads by using the device can be adjusted according to the requirement, the accurate regulation and control of the structure of a high polymer foaming particle product can be realized, the quality is better ensured, and the defect that the process of an extrusion continuous foaming method is unstable is overcome; the pressure relief rate of the extruder in the extrusion foaming process is low and cannot be adjusted and controlled, the uniformity of the foam holes of the foaming beads is poor, the foaming multiplying power is low, the opening rate of the foaming beads is high, and the device has the advantages of being stable, reliable in control, efficient in production and low in cost;
(3) the technical scheme adopts a mode that a heating device uniformly heats the whole high-pressure-ultrahigh pressure container by foaming polymer beads, so that the temperature difference change of the whole temperature of the high-pressure-ultrahigh pressure container is less, the temperature of the whole temperature system is basically consistent, no temperature difference exists, the consistency of foaming quality is ensured, the unstable factor that the temperature difference is large when the foaming temperature of an extruder is changed from the melting temperature to the extrusion foaming temperature is overcome, the temperature change range of the extruder is generally reduced from the melting temperature (about 200 ℃) to the foaming temperature (about 100 ℃) in the extrusion foaming process of the extruder, and the temperature difference change is large;
(4) the high polymer expanded bead product prepared by the device has large expansion ratio, fine and uniform cell structure, and the closed cell rate is up to more than 90 percent, thereby overcoming the defect of low closed cell rate of the extrusion continuous foaming method.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic plan view of a continuous foaming apparatus for preparing low-density polymer particles by continuous foaming according to the present invention;
FIG. 2 is a schematic plan view of a polymer particle delivery system provided by the present invention when the pressure conveyor is a venturi;
FIG. 3 is a schematic plan view of a polymer particle conveying system provided by the present invention in a storage state when the pressure conveyor is a pneumatic cylinder pressure conveying device for conveying the particle material;
fig. 4 is a schematic plan view of the feeding state of the polymer particle conveying system provided by the present invention when the pressure conveyor is a cylinder particle material pressure conveying device.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a continuous foaming method and a continuous foaming device for preparing low-density polymer particles by continuous foaming, which comprise a bead foaming system 1, and a polymer particle conveying system 2, a gas conveying system 3 and a liquid conveying system 4 which are respectively communicated with the bead foaming system 1, as shown in figure 1.
The bead foaming system 1 comprises a polymer bead foaming heating high-pressure-ultrahigh-pressure vessel 11, a foaming nozzle 12 arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure vessel 11, a nozzle gap pressure adjusting block 13 arranged above the foaming nozzle 12, a foaming bead collecting box 14 arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure vessel 11, a foaming bead discharge port 15 arranged on one side of the foaming bead collecting box 14, and a heating device. The heating means herein is used to heat the contents of the polymer bead expansion heating high pressure-ultra high pressure vessel 11, and in this embodiment is preferably a heating jacket 16 disposed on the outer wall of the polymer bead expansion heating high pressure-ultra high pressure vessel 11. The pressure of the high-pressure-ultrahigh-pressure container 11 for foaming and heating the polymer beads can be freely adjusted along with the pressure of the gas conveying system 3, and the pressure adjusting range is 0-50 MPa.
Wherein the polymer particle conveying system 2 comprises a polymer particle storage tank 21 for storing polymer particles, and a pressure conveyor 22 communicated with the polymer particle storage tank 21; the pressure conveyor 22 is used to quantitatively convey the polymer particles into the high-pressure-ultrahigh-pressure vessel 11 for foaming and heating the polymer beads.
Wherein the liquid conveying system 4 is used for conveying the mixed liquid of the suspension liquid and the separant at the temperature of 60-200 ℃ into the polymer bead foaming heating high-pressure-ultrahigh-pressure container 11. Specifically, in the present embodiment, the liquid delivery system 4 includes a liquid storage tank 41 for storing the suspension and the release agent, a high-pressure liquid pump 42 in communication with the liquid storage tank 41, a liquid heater 43 in communication with the high-pressure liquid pump 42, and a check valve 44 in communication with the liquid heater 43, the check valve 44 being in communication with the high-pressure-ultrahigh-pressure polymer bead foaming-heating vessel 11. In addition, the suspension is one or more mixed suspension of talcum powder suspension, calcium carbonate suspension or barium sulfate suspension; the separant is one or more of aqueous soap separant, aqueous zinc stearate and calcium stearate, and soap water separant. Wherein the relative density of the suspension is 0.5-5.0.
Wherein the gas conveying system 3 is used for conveying the mixed gas of carbon dioxide and nitrogen with the temperature of 60-350 ℃ and the pressure of 0-50 MPa into the polymer bead foaming heating high-pressure-ultrahigh pressure container 11. Specifically, in the present embodiment, the gas delivery system 3 includes a carbon dioxide storage tank 31 for storing carbon dioxide, a nitrogen storage tank 32 for storing nitrogen, a first high-pressure pump 33 communicated with the carbon dioxide storage tank 31, a second high-pressure pump 34 communicated with the nitrogen storage tank 32, and a gas heater 35 respectively communicated with the first high-pressure pump 33 and the second high-pressure pump 34, wherein the gas heater 35 is communicated with the polymer bead foaming heating high-pressure-ultrahigh-pressure vessel 11 or the pressure conveyor 22.
The working principle of the device for continuously preparing the expanded polymer beads is as follows: firstly, a liquid high-pressure pump 42 (the pressure is 0-50 MPa, and the pressure is selected according to the permeability of gas to polymer) is used for conveying suspension and a separant in a liquid storage tank 41 into a liquid heater 43 for heating, the heating temperature is 60-200 ℃, then the suspension and the separant are conveyed into a polymer bead foaming heating high-pressure-ultrahigh pressure container 11 through a one-way valve 44, the suspension and the separant are filled in the whole polymer bead foaming heating high-pressure-ultrahigh pressure container 11, simultaneously a heating sleeve 16 is used for heating the suspension and the separant in the polymer bead foaming heating high-pressure-ultrahigh pressure container 11, the heating temperature is 60-350 ℃ (the temperature is determined according to the melting temperature of the polymer, the general process temperature parameter is lower than the melting point of the polymer, preferably, the temperature is controlled to be 5-150 ℃ below the melting point of the polymer, different polymers have different melting points), when the required temperature is reached, the first high-pressure pump 33 (with the pressure of 0-50 MPa) quantitatively conveys the carbon dioxide in the carbon dioxide storage tank 31 into the gas heater 35 (with the heating temperature of 60-350 ℃) and the second high-pressure pump 34 (with the pressure of 0-50 MPa) quantitatively conveys the nitrogen in the nitrogen storage tank 32 into the gas heater 35 (with the heating temperature of 60-350 ℃) at the same time, then the polymer particles with the preheating temperature of 60-300 ℃ in the polymer particle storage tank 21 are conveyed into the polymer bead foaming heating high-pressure-ultrahigh-pressure container 11 through the pressure conveyor 22 and the heated high-pressure mixed gas (with the pressure of 0-50 MPa) in sequence or together, at the moment, the polymer beads are acted by the temperature of 60-350 ℃ and the pressure of 0-50 MPa in the polymer bead foaming heating high-ultrahigh-pressure container 11, the polymer particles are subjected to swelling and permeation of mixed gas, meanwhile, because the relative density of the polymer particles is smaller than that of a suspension, the polymer particles gradually drift upwards under the action of the suspension force, the polymer particles reach the foaming nozzle 12 after a period of time (5-60 minutes), then the polymer particles are rapidly and continuously sprayed out through a gap between the nozzle gap pressure adjusting block 13 and the foaming nozzle 12, the polymer particles expand and foam due to rapid pressure relief, polymer foaming beads are formed, the pressure at the foaming nozzle 12 is controlled to be 0.5-15 MPa, the pressure relief rate is 1-10000MPa/s, finally the polymer foaming beads are collected by a foaming bead collecting box 14 and then discharged from a foaming bead discharging port 15, and then the foaming beads are washed, dried and packaged, so that the complete manufacturing method for preparing the foaming beads through continuous foaming is realized.
Preferably, as shown in fig. 2, the pressure conveyer 22 can be a venturi tube, which works on the principle that the cylinder body is contracted and then gradually expanded, and the polymer particles in the polymer particle storage tank 21 are conveyed into the high-pressure-ultrahigh pressure vessel 11 for polymer bead foaming and heating by using the pressure difference between the inlet section and the smallest section to perform pressurization and heating and gas permeation, so as to achieve the purpose of continuously conveying the polymer particle material in a sealed manner under high pressure, so as to continuously prepare the expanded polymer beads. In this embodiment, the gas heater 35 is directly connected to the venturi.
In addition, as shown in fig. 3 and 4, the pressure conveyer 22 may be a pneumatic cylinder granular material pressure conveyer, which includes a cylinder body 221 connected to the high-pressure-ultrahigh pressure vessel 11 for foaming and heating the polymer beads, a piston rod 222 slidably disposed in the cylinder body 221, and a driving cylinder 223 for driving the piston rod 222 to telescopically slide in the cylinder body 221; the piston rod 222 is provided with a polymer particle storage cavity 2221, when the piston rod 222 is in a contracted state, the polymer particle storage cavity 2221 is communicated with the polymer particle storage tank 21, and when the piston rod 222 is in an extended state, the polymer particle storage cavity 2221 is communicated with the polymer bead foaming heating high-pressure-ultrahigh-pressure container 11. In the technical scheme, the gas heater 35 is directly communicated with the inside of the high-pressure-ultrahigh-pressure container 11 for foaming and heating polymer beads, and the working principle is as follows: the piston rod 222 is located below the polymer particle storage tank 21, the polymer particle storage chamber 2221 is communicated with the discharge opening of the polymer particle storage tank 21, and polymer particles freely fall into the polymer particle storage chamber 2221 under the action of gravity, as shown in fig. 3, the pressure conveyor 22 is in a storage state; then the driving cylinder 223 pushes the piston rod 222 to move forward, and at this time, the polymer particle storage chamber 2221 will communicate with the polymer bead foaming heating high-pressure-ultra-high-pressure vessel 11, and finally the polymer particles are released into the polymer bead foaming heating high-pressure-ultra-high-pressure vessel 11, as shown in fig. 4, the feeding state of the pressure conveyor 22 is shown. The piston rod 222 is driven by the driving cylinder 223 to reciprocate, so that the purpose of high-pressure continuous sealed conveying of polymer particle materials is achieved, and the expanded high polymer beads can be prepared continuously.
In conclusion, the technical scheme can realize high-pressure continuous sealed conveying of high polymer particle materials, can ensure continuous preparation of foamed high polymer foamed beads, and has the outstanding advantages of high production efficiency and low cost. In addition, in the technical scheme, the pressure of the high-pressure and ultrahigh-pressure vessel 11 for foaming and heating the polymer beads is derived from the pressure of the mixed gas of carbon dioxide and nitrogen in the gas conveying system 3, so that the pressure of the high-pressure and ultrahigh-pressure vessel 11 for foaming and heating the polymer beads can be freely adjusted along with the adjustment of the pressure of the mixed gas of carbon dioxide and nitrogen, the pressure of the high-pressure and ultrahigh-pressure vessel 11 for foaming and heating the polymer beads can be adjusted within the adjustment range of 0-50 MPa by adjusting the pressure of the high-pressure and ultrahigh-pressure vessel 11 for foaming and heating the polymer beads and the pressure of the foaming nozzle 12 through the foaming nozzle 12 with adjustable pressure relief rate arranged above the high-pressure and ultrahigh-pressure vessel 11 for foaming and heating the polymer beads according to the process pressure requirement, the pressure adjustment range of the technical scheme of the invention is wide, the pressure can easily reach 50MPa, the pressure relief rate of the pressure system for continuously preparing the foamed high polymer beads can be adjusted according to requirements, so that the structure of the high polymer foamed particle product can be accurately regulated and controlled, the quality is better ensured, and the defect of unstable process of an extrusion continuous foaming method is overcome; the extruder has small pressure relief rate in the extrusion foaming process and cannot be adjusted and controlled, the foam uniformity of the foaming beads is poor, the foaming multiplying power is small, the opening rate of the foaming beads is large, and the technical scheme has the advantages of being more stable, more reliable to control, more efficient to produce and low in cost.
In addition, the technical scheme adopts a mode that the heating device uniformly heats the whole high-pressure-ultrahigh-pressure container 11 by foaming the polymer beads, and the heating device is provided with the heating sleeve 16, so that the temperature difference change of the whole temperature of the high-pressure-ultrahigh-pressure container 11 by foaming and heating the polymer beads is small, the temperature of the whole temperature system is basically consistent, no temperature difference exists, the consistency of foaming quality is ensured, the unstable factor that the temperature difference is large when the foaming temperature of the extruder changes from the melting temperature to the extrusion foaming temperature is overcome, and the temperature change range of the extrusion foaming process of the extruder is generally reduced from the melting temperature (about 200 ℃) to the foaming temperature (about 100 ℃) and the temperature difference change is large.
Finally, the high polymer expanded bead product prepared by the technical scheme has large expansion ratio, fine and uniform cell structure and closed cell rate of more than 90 percent, and overcomes the defect of low closed cell rate of an extrusion continuous foaming method.
The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.
Claims (10)
1. A method of continuously foaming polymer particles, comprising the steps of:
s1, conveying the suspension and the separant mixed solution at the temperature of 60-200 ℃ into a polymer bead foaming heating high-pressure-ultrahigh-pressure container, and filling the polymer bead foaming heating high-pressure-ultrahigh-pressure container with the suspension and the separant mixed solution; wherein the density of the selected suspension is greater than the density of the polymer particles, and the relative density of the suspension is 0.5-5.0;
s2, using a heating device to heat the suspension and the separant mixed liquid in the high-pressure and ultrahigh-pressure container for foaming of the polymer beads, and uniformly heating the whole to make the temperature in the high-pressure and ultrahigh-pressure container uniform and consistent, wherein the heating temperature is 60-350 ℃;
preferably, the temperature is controlled to be 5-150 ℃ below the melting point of the polymer;
s3, after the suspension and the separant are uniformly heated to a specified temperature, sequentially or simultaneously conveying polymer particles with the preheating temperature of 60-300 ℃ and carbon dioxide and nitrogen mixed gas with the temperature of 60-350 ℃ into a polymer bead foaming and heating high-pressure-ultrahigh-pressure container; the pressure of the high-pressure-ultrahigh-pressure container for foaming and heating the polymer beads can be freely adjusted along with the pressure of a gas conveying system, and the pressure adjusting range is 0-50 MPa;
s4, because the polymer particles are at the temperature of 60-350 ℃ and the pressure of 0-50 MPa in a polymer bead foaming heating high-pressure-ultrahigh pressure container, the polymer particles are swelled and permeated by mixed gas, because the polymer particles have smaller relative density than a suspension, the polymer particles gradually move upwards under the action of the suspension, and are continuously sprayed out from a foaming nozzle above the polymer bead foaming heating high-pressure-ultrahigh pressure container after 5-60 minutes, the pressure relief rate of foaming can be adjusted by adjusting the gap width between the foaming nozzle and a pressure adjusting block arranged above the polymer bead foaming heating high-pressure-ultrahigh pressure container, and the pressure of the polymer bead foaming heating high-ultrahigh pressure container and the pressure of the foaming nozzle are adjusted, so that the pressure relief rate of the foaming nozzle is controlled, and the adjustment range of the gap width is 0.1-10.0 mm; the polymer particles expand and foam due to the rapid pressure relief, forming polymer foam beads;
s5, collecting the polymer expanded beads ejected from the expansion nozzle.
2. The continuous foaming process of claim 1, further comprising the steps of:
s6, washing, drying and packaging the collected polymer expanded beads.
3. The continuous foaming process of claim 1, wherein the suspension is one or more of talc suspension, calcium carbonate suspension or barium sulfate suspension.
4. The continuous foaming process of claim 1, wherein the release agent is one or more of an aqueous soap release agent, aqueous zinc stearate and aqueous calcium stearate, and a soap-water release agent.
5. The continuous foaming method of polymer particles as claimed in claim 1, wherein the pressure of the polymer particles sprayed from the foaming nozzle in step S4 is controlled to be 0.5 to 15MPa, and the pressure-releasing speed is 1 to 10000 MPa/S.
6. A polymer particle continuous foaming device comprises a bead foaming system (1), and a polymer particle conveying system (2), a gas conveying system (3) and a liquid conveying system (4) which are respectively communicated with the bead foaming system (1), and is characterized in that:
the bead foaming system (1) comprises a polymer bead foaming heating high-pressure-ultrahigh-pressure container (11), a foaming nozzle (12) with adjustable pressure relief rate, which is arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11), a nozzle gap pressure adjusting block (13) which is arranged above the foaming nozzle (12), a foaming bead collecting box (14) which is arranged above the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11), a foaming bead discharging port (15) which is arranged on one side of the foaming bead collecting box (14), and a heating device which uniformly heats the whole polymer bead foaming heating high-pressure-ultrahigh-pressure container (11);
the polymer particle conveying system (2) comprises a polymer particle storage tank (21) for storing polymer particles, and a pressure conveyor (22) communicated with the polymer particle storage tank (21); the pressure conveyor (22) is used for quantitatively conveying polymer particles into the high-pressure-ultrahigh-pressure vessel (11) for foaming and heating the polymer beads;
the liquid conveying system (4) is used for conveying the mixed liquid of the suspension liquid and the separant at the temperature of 60-200 ℃ into the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11); the gas conveying system (3) is used for conveying the mixed gas of carbon dioxide and nitrogen with the temperature of 60-350 ℃ and the pressure of 0-50 MPa into the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11).
7. The continuous foaming apparatus of claim 6, wherein the suspension is one or more of talc suspension, calcium carbonate suspension or barium sulfate suspension; the separant is one or more of aqueous soap separant, aqueous zinc stearate, aqueous calcium stearate and soap water separant.
8. A device for the continuous foaming of polymer particles according to claim 6, wherein the liquid delivery system (4) comprises a liquid storage tank (41) for storing the suspension and the isolating agent, a high-pressure liquid pump (42) in communication with the liquid storage tank (41), a liquid heater (43) in communication with the high-pressure liquid pump (42), and a one-way valve (44) in communication with the liquid heater (43), the one-way valve (44) being in communication with the high-pressure-ultra-high pressure vessel (11) for the foaming heating of the polymer beads;
the gas conveying system (3) comprises a carbon dioxide storage tank (31) for storing carbon dioxide, a nitrogen storage tank (32) for storing nitrogen, a first high-pressure pump (33) communicated with the carbon dioxide storage tank (31), a second high-pressure pump (34) communicated with the nitrogen storage tank (32), and a gas heater (35) respectively communicated with the first high-pressure pump (33) and the second high-pressure pump (34), wherein the gas heater (35) is communicated with the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11) or the pressure conveyor (22).
9. A device for the continuous foaming of polymer particles according to claim 8, wherein the pressure conveyor (22) is a venturi tube and the gas heater (35) is in communication with the pressure conveyor (22).
10. The continuous foaming apparatus of polymer beads according to claim 6, wherein the pressure conveyor (22) comprises a cylinder (221) communicating with the high-pressure-ultrahigh-pressure vessel (11) for foaming and heating the polymer beads, a piston rod (222) slidably connected to the cylinder (221), and a driving cylinder (223) for driving the piston rod (222) to telescopically slide in the cylinder (221); the piston rod (222) is provided with a polymer particle storage cavity (2221), when the piston rod (222) is in a contraction state, the polymer particle storage cavity (2221) is communicated with the polymer particle storage tank (21), and when the piston rod (222) is in an extension state, the polymer particle storage cavity (2221) is communicated with the inside of the polymer bead foaming heating high-pressure-ultrahigh-pressure container (11).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011295566.3A CN112356373A (en) | 2020-11-18 | 2020-11-18 | Continuous foaming method and continuous foaming device for polymer particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011295566.3A CN112356373A (en) | 2020-11-18 | 2020-11-18 | Continuous foaming method and continuous foaming device for polymer particles |
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| Publication Number | Publication Date |
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| CN112356373A true CN112356373A (en) | 2021-02-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011295566.3A Pending CN112356373A (en) | 2020-11-18 | 2020-11-18 | Continuous foaming method and continuous foaming device for polymer particles |
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| Country | Link |
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| CN (1) | CN112356373A (en) |
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