CN110815693A - Wood-plastic physical micro-foaming extrusion injection molding machine and molding process - Google Patents
Wood-plastic physical micro-foaming extrusion injection molding machine and molding process Download PDFInfo
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- CN110815693A CN110815693A CN201911227870.1A CN201911227870A CN110815693A CN 110815693 A CN110815693 A CN 110815693A CN 201911227870 A CN201911227870 A CN 201911227870A CN 110815693 A CN110815693 A CN 110815693A
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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
- B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
- B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
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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
- B29C44/3442—Mixing, kneading or conveying the foamable material
- B29C44/3446—Feeding the blowing agent
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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
- B29C44/36—Feeding the material to be shaped
- B29C44/38—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length
- B29C44/42—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum
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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
- B29C44/36—Feeding the material to be shaped
- B29C44/38—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length
- B29C44/42—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum
- B29C44/421—Feeding the material to be shaped into a closed space, i.e. to make articles of definite length using pressure difference, e.g. by injection or by vacuum by plastizising the material into a shot cavity and injecting using a plunger
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- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
The invention relates to a wood-plastic physical micro-foaming extrusion injection molding machine and a molding process, belonging to the field of wood-plastic production equipment, and comprising a double-screw extruder and an injection machine, wherein the double-screw extruder comprises a charging barrel, two screws are arranged in the charging barrel, a hopper is arranged at the input end of the charging barrel, a charging barrel precursor is arranged at the output end of the charging barrel, a connecting body is arranged below the charging barrel precursor, a supercritical fluid injector is arranged at the side end of the connecting body, a first cavity is arranged in the connecting body, the upper end of the connecting body is communicated with the charging barrel precursor through the first cavity, the side end of the connecting body is communicated with the supercritical fluid injector through the first cavity, a gear pump is arranged below the connecting body, the injection machine comprises an injection cylinder, an injection cylinder; the method aims to solve the problems of uneven size of pores of the wood-plastic product, large molding brittleness, poor compactness, easy cracking and high density of the product, and the whole equipment has a simple structure and is convenient to process.
Description
Technical Field
The invention relates to the technical field of wood-plastic material production equipment, in particular to a wood-plastic physical micro-foaming extrusion injection molding machine and a molding process under the trend of replacing wood with plastic and reducing the weight of materials.
Background
The wood-plastic composite material is a novel composite material obtained by adding plant fibers such as wood, sisal, bagasse, rice chaff, bamboo powder and the like into thermoplastic plastics in the form of powder, fibers and the like as fillers and carrying out melt processing and compounding. Compared with the traditional wood material, the wood material has the advantages of beautiful appearance, water resistance, moth prevention, corrosion resistance, difficult cracking and the like, and is widely used for manufacturing wood substitute products, such as various wrappages, trays and warehouse liner plates or outdoor building materials, public facilities and the like. In addition, most of the wood-plastic composite materials are prepared by adopting recycled resources, thereby being beneficial to saving resources and protecting the environment. Most of the wood-plastic composite materials used in the market at present are cut or processed after extrusion molding.
The wood-plastic composite foaming material is prepared by adopting a chemical foaming method in the prior art: the raw materials such as plastic, wood powder, mineral filler, auxiliary agent, modifier, foaming agent and the like are mixed according to the mass ratio and are heated and melted by plastic molding equipment to form the composite material with the continuously and uniformly distributed foaming pores. The density of the product is close to that of wood, the mechanical strength is far higher than that of the wood, and the resin consumption is reduced by half, so that the product cost is lower. Compared with the common wood-plastic composite material, the wood-plastic foaming material has the advantages of light material and stronger wood texture, meets the requirement of light weight development of the material, and has wide attention in development and application in recent years.
At present, two foaming technologies of physical foaming and chemical foaming are commonly adopted as foaming modes of common plastic products: the chemical foaming method is a method of foaming plastic by generating gas by a chemical method, and foaming is performed by heating a chemical foaming agent added to the plastic to decompose and release gas, or foaming is performed by using gas released by chemical reaction between plastic components. The injection molding process of foamed plastic by using chemical foaming agent is basically the same as general injection molding process, and the heating, mixing, plasticizing and most of foaming expansion of plastic are completed in an injection molding machine. The physical foaming agent used in the physical foaming method has relatively low cost, no residue after foaming and little influence on the performance of the foamed plastic. In the prior art, chinese patent application No. 201610606340.8 discloses a carbon dioxide foamed plastic extrusion granulation and molding device, wherein a supercritical carbon dioxide filling valve is additionally arranged on a cylinder of a twin-screw extruder, so that a melt and carbon dioxide are mixed in the cylinder of the screw extruder for foaming plastic raw material particles.
The physical foaming is directed to the foaming of plastic raw material particles, that is, raw material particles such as PE and PVC are used as objects of foaming and plasticizing. Firstly, the injection molding plastic-wood product cannot be produced, secondly, when the injection molding plastic-wood product is used for processing a plastic-wood product taking wood powder and plastics as main raw materials, if the plasticizing equipment is adopted, after a physical foaming agent is injected into a melt in a screw extruder, due to the existence of the raw material wood powder in the melt, supercritical gas of the foaming agent can be diffused along fibers of the plastic-wood product, so that the release of the gas is easily caused, and the foaming effect of the plastic-wood product is poor. The problem of excessive gas release can be solved by adopting chemical foaming, but the chemical foaming not only uses a large amount of foaming agent and produces large foam holes, the uniformity is greatly influenced by the uniform distribution degree of the foaming agent, the maximum degree of a foamed product can reach 0.6-0.7g/cm for thin film planting, and the weather resistance is greatly influenced by the instability of a chemical preparation; most importantly, for the chemical foaming of the wood plastic, a foaming regulator must be added to reduce the large bubbles in the melt and prevent excessive gas from being released.
In addition, due to the fact that wood powder and plastic have different flowability, molecular structures cannot be adhered to each other, continuous extrusion molding is easy, and the purpose of light weight of replacing wood with plastic cannot be achieved even if the traditional injection molding cannot be realized or even if the product is formed, the brittleness and the compactness are poor and the product is easy to crack. Therefore, special equipment is needed for processing the wood-plastic injection molding micro-foaming product taking wood powder and plastics as main raw materials, and the invention provides production equipment and process special for the wood-plastic physical micro-foaming product in order to make up the blank.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art, provides a wood-plastic physical micro-foaming extrusion injection molding machine and a molding process thereof, solves the problems that gas is easy to release in the physical foaming process of a wood-plastic injection molding product, and the prepared product has uneven pore size, large molding brittleness, poor compactness, easy cracking and high density, and has simple integral equipment structure and convenient processing.
The technical scheme for solving the technical problems is as follows: a wood-plastic physical micro-foaming extrusion injection molding machine comprises a double-screw extruder and an injection mechanism, and is characterized in that the double-screw extruder comprises a charging barrel, two screws are arranged in the charging barrel, the two screws are arranged in parallel and are mutually meshed, the input end of the charging barrel is provided with a hopper, the output end of the charging barrel is provided with a charging barrel precursor, a connecting body is arranged below the charging barrel precursor, a supercritical fluid injector is arranged at the side end of the connecting body and is used for conveying supercritical gas, a first cavity is arranged in the connecting body, the upper end of the connecting body is communicated with the charging barrel precursor through the first cavity, the side end of the connecting body is communicated with the supercritical fluid injector through the first cavity, a gear pump is arranged below the connecting body, the injection mechanism comprises an injection cylinder, an injection cylinder precursor and a nozzle, the front end of, the lower part of the gear pump is connected with the top end of the injection cylinder precursor through a check valve, so that the reverse flow impact during injection is prevented.
Furthermore, the wood-plastic physical micro-foaming extrusion injection type injection molding machine comprises an upper layer and a lower layer, wherein the upper layer is a double-screw extruder, the injection mechanism is arranged right below the double-screw extruder, and the upper layer double-screw extruder and the injection mechanism are arranged in parallel.
Furthermore, the first cavity is arranged to be hollow in the vertical direction, a flow divider is arranged in the first cavity and arranged at the middle lower part of the first cavity, a preset distance is reserved between the top end of the flow divider and the upper wall of the first cavity, a connecting port of the supercritical fluid injector and the first cavity is arranged above the flow divider in the first cavity, and the lower end of the flow divider protrudes out of the connecting body and is inserted into the gear pump.
Further, the flow divider comprises a cylindrical portion and conical portions arranged at two ends of the cylindrical portion, at least one annular groove is formed in the surface of the cylindrical portion along the circumferential direction of the cylindrical portion, a preset number of strip-shaped grooves are formed in the surfaces of the cylindrical portion and the conical portions, each strip-shaped groove is communicated with the annular groove, the strip-shaped grooves in the surface of the conical portion are collected to the end portion of the conical portion, the annular grooves divide the flow divider into at least two parts, and the strip-shaped grooves in the surfaces of the flow dividers of the adjacent parts are arranged in a staggered mode in the vertical direction.
Further, the gear pump includes the gear pump casing, is provided with two gear shafts in the gear pump casing, and two gear shaft parallel arrangement horizontal form and intermeshing, second gear shaft setting are under first gear shaft, gear pump casing upper end is linked together with the connector as the input, and gear pump casing lower extreme is linked together as output and injection jar precursor, and the material gets into the gear pump casing and cuts and export to the injection jar precursor through the rotation of first gear shaft, second gear shaft in proper order.
Further, check valve includes valve case and spheroid, and the valve case top sets up to the input, and the valve case bottom sets up to the output, is provided with the spheroid with output port looks adaptation in the valve case.
And a molding process using the injection molding machine as described above, characterized by comprising the steps of:
1) the raw materials comprise mixed powder consisting of polyethylene, wood powder and additives and supercritical gas;
2) heating and uniformly mixing the mixed powder, cooling, feeding the mixed powder into a charging barrel through a hopper, and mixing, plasticizing and extruding in a double-screw extruder to obtain a melt;
3) the melt enters the connecting body through the barrel precursor and is preliminarily mixed with the supercritical gas from the supercritical fluid injector in the first cavity;
4) uniformly mixing the melt and the supercritical fluid under the action of a gear pump to obtain a stable melt polymer, scattering the molecular chain structure of the melt through the rotary shearing of an internal gear pump to fully mix the melt with supercritical gas molecules, and coupling and wrapping the melt polymer, wood powder and supercritical gas to form the stable melt polymer;
5) and injecting the melt polymer into a mold cavity, and completing product molding through low-pressure filling and gas bubble growing until the mold cavity is filled.
Further, the additive consists of toner, a coupling agent, an internal lubricant and an external lubricant.
Further, the raw materials comprise the following components in parts by weight:
polyethylene 50-60
29-44 parts of wood powder
Toner 1-2
Coupling agent 3-5
0.5-1 part of internal lubricant
External lubricant 0.5-1
Supercritical gas 1-2
Further, the coupling agent is maleic anhydride, the internal lubricant is stearic acid, the external lubricant is PE wax, and the supercritical gas is nitrogen or carbon dioxide.
The invention has the beneficial effects that: according to the invention, through the charging barrel precursor and the connector arranged at the front end of the double-screw extruder, the powdery material is extruded into the melt through the double-screw extruder and then is mixed with the supercritical gas from the supercritical fluid injector in the connector, and then the large bubbles are sheared into uniform small bubbles through the rotary shearing of the gear pump, so that the release of gas is prevented, the melt and the supercritical gas are uniformly mixed, and the uniformity of the bubbles and the quality of the melt after plasticization are improved; compared with the prior art that the mixing operation of the melt and the supercritical gas is completed in a double-screw extruder, the scheme can solve the problem that the supercritical gas is released along the diffusion of wood-plastic fibers, effectively realizes the full mixing and plasticizing of wood powder and plastic particles in the double-screw extruder, avoids the poor bonding force between the wood powder and the plastic particles, uneven foaming and easy release of bubbles caused by the mixing of the supercritical gas and the wood powder, and further solves the problems of large molding brittleness, poor compactness and easy cracking of a product; in addition, the structure of the scheme is simple, and the installation is convenient.
Drawings
FIG. 1 is a schematic perspective view of an embodiment of the present invention;
FIG. 2 is a schematic front view of an embodiment of the present invention;
FIG. 3 is a schematic top view of an embodiment of the present invention;
FIG. 4 is an enlarged view of the structure at A in FIG. 2;
FIG. 5 is a schematic view of a diverter according to an embodiment of the present invention.
In the figure: 1. the device comprises a double-screw extruder, 11 parts of a cylinder, 12 parts of a screw, 13 parts of a hopper, 14 parts of a reduction gearbox, 15 parts of a driving motor, 2 parts of a cylinder precursor, 3 parts of a connecting body, 31 parts of a first cavity, 4 parts of a supercritical fluid injector, 5 parts of a gear pump, 51 parts of a gear pump shell, 52 parts of a gear shaft, 521 parts of a first gear shaft, 522 parts of a second gear shaft, 53 parts of a universal coupling, 54 parts of a gear pump driving component, 6 parts of an injection mechanism, 61 parts of an injection cylinder, 62 parts of an injection cylinder precursor, 63 parts of a nozzle, 7 parts of a check valve, 71 parts of a valve shell, 72 parts of a ball, 8 parts of a flow divider, 81 parts of a cylindrical part, 82 parts of a.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
As shown in the figures, the wood-plastic physical micro-foaming extrusion injection molding machine of the embodiment comprises a double-screw extruder 1 and an injection mechanism 6, the double-screw extruder 1 comprises a charging barrel 11, two screws 12 are arranged in the charging barrel 11, the two screws 12 are arranged in parallel and are meshed with each other, the two screws 12 are connected with a driving motor 15 through a reduction gearbox 14 at the front end of the two screws, a hopper 13 is arranged at the input end of the charging barrel 11, a charging barrel precursor 2 is arranged at the output end of the charging barrel 11, a connecting body 3 is arranged below the charging barrel precursor 2, a supercritical fluid injector 4 is arranged at the side end of the connecting body 3, a metering pump is connected outside the supercritical fluid injector 4 and is used for quantitatively delivering supercritical gas, a first cavity 31 is arranged in the connecting body 3, the upper end of the connecting body 3 is communicated with the charging barrel precursor 2 through the first cavity, a gear pump 5 is arranged below the connecting body 3, the injection mechanism 6 comprises an injection cylinder 61, an injection cylinder precursor 62 and a nozzle 63, the front end of the injection cylinder 61 is connected with the injection cylinder precursor 62, the front end of the injection cylinder precursor 62 is connected with the nozzle 63, and the lower part of the gear pump 5 is connected with the top end of the injection cylinder precursor 62 through a check valve 7. The wood-plastic physical micro-foaming extrusion injection type injection molding machine comprises an upper layer and a lower layer, wherein the upper layer is a double-screw extruder 1, an injection mechanism 6 is arranged under the double-screw extruder 1, and the double-screw extruder 1 and the injection mechanism 6 on the upper layer are arranged in parallel.
The molding process using the injection molding machine as described above includes the steps of:
1) the raw materials comprise mixed powder consisting of polyethylene, wood powder and additives and supercritical gas;
2) heating and uniformly mixing the mixed powder, cooling, feeding the mixed powder into a charging barrel through a hopper, and mixing, plasticizing and extruding in a double-screw extruder to obtain a melt;
3) the melt enters the connecting body through the barrel precursor and is preliminarily mixed with the supercritical gas from the supercritical fluid injector in the first cavity;
4) the melt and the supercritical fluid are uniformly mixed under the action of a gear pump to obtain a stable melt polymer;
5) and injecting the melt polymer into a mold cavity, and completing product molding through low-pressure filling and gas bubble growing until the mold cavity is filled.
The additive consists of toner, a coupling agent, an internal lubricant and an external lubricant;
the coupling agent adopts maleic anhydride, the internal lubricant adopts stearic acid, the external lubricant adopts PE wax, and the supercritical gas adopts nitrogen.
The weight parts of the raw materials in the embodiment are as follows:
polyethylene 50
Wood flour 44
Stearic acid 0.5
PE wax 0.5
According to the scheme, the powder material is extruded into the melt to the connector through the charging barrel precursor and the connector arranged at the front end of the double-screw extruder, and is mixed with supercritical gas from a supercritical fluid injector in the connector, and then is sheared by the rotation of the gear pump to shear large bubbles into uniform small bubbles, so that the addition of a foaming regulator is not needed, the release of gas is prevented, the melt is uniformly mixed with the supercritical gas, the uniformity of bubbles and the quality of a plasticized substance are improved, the fully mixed melt-supercritical gas mixture is pushed and injected into a next-stage mold cavity through the injection oil cylinder by arranging the mold cavity at the front end of the injection mechanism, and the molding and cooling are completed. The process of the equipment is adopted, namely, the mixing of the wood powder and the plastic particles is firstly completed, then the wood powder and the plastic particles are blended with the supercritical gas, the two-step extrusion injection molding is adopted, the upper stage adopts a parallel double-screw structure, the wood powder and the plastic particles are mixed and plasticized efficiently, and the problems of uneven single-screw mixing and easy powder deposition are solved; a common storage tank is arranged at the next stage for storing the mixed melt; an internal gear pump mixing device is arranged between the upper-stage double screw and the injection cylinder barrel, and aims to fully mix the supercritical gas in the melt with the melt. Compared with the prior art that the mixing operation of the melt and the supercritical gas is completed in the double-screw extruder, the scheme can effectively realize the full mixing and plasticizing of the wood powder and the plastic particles in the double-screw extruder, and avoid poor bonding force and uneven foaming of the wood powder and the plastic particles caused by the mixing of the supercritical gas and the supercritical gas, thereby solving the problems of large product forming brittleness, poor compactness, easy cracking and large density; in addition, the required basic double screw extruder structure of this scheme's structure can, need not to carry out the measure of changing of valve member to double screw extruder, each part simple structure, the installation of being convenient for.
In another embodiment of the present invention, the first cavity 31 is vertically hollow, a flow divider 8 is disposed in the first cavity 31, the flow divider 8 is disposed at the middle lower part of the first cavity 31, a predetermined distance is left between the top end of the flow divider 8 and the upper wall of the first cavity 31, i.e. a space for blending the supercritical gas and the melt extruded by the twin-screw extruder is formed therein, a connection port of the supercritical fluid injector 4 and the first cavity 31 is disposed above the flow divider 8 in the first cavity 31, and the lower end of the flow divider 8 protrudes from the connecting body 3 and is inserted into the gear pump 5.
Adopt the connector of the built-in above-mentioned first cavity structures, can realize that supercritical gas and the fuse-element that comes from the twin-screw extruder blend smoothly, be equipped with the shunt that sets up, make the supercritical gas and the fuse-element primary mixing of liquid phase, not only mix more evenly, it is little to equipment influence simultaneously, do benefit to extension equipment life.
The weight parts of the raw materials in the embodiment are as follows:
polyethylene 55
Wood flour 35
In another embodiment of the present invention, the flow divider 8 includes a cylindrical portion 81 and conical portions 82 disposed at two ends of the cylindrical portion 81, as shown in fig. 5, the surface of the cylindrical portion 81 is provided with at least one annular groove 83 along the circumferential direction thereof, the surfaces of the cylindrical portion 81 and the conical portion 82 are further provided with a predetermined number of strip-shaped grooves 84, each strip-shaped groove 84 is communicated with the annular groove 83, the strip-shaped grooves 84 on the surface of the conical portion 82 are converged at the end of the conical portion 82, the annular groove 83 divides the flow divider 8 into at least two parts, and the strip-shaped grooves 84 on the surface of the flow divider 8 of adjacent parts are staggered in the vertical direction.
The structure of above-mentioned shunt can realize the intensive mixing of supercritical gas in the fuse-element through the cooperation of the annular groove that sets up and bar groove, makes gas distribution more even in the fuse-element.
The weight parts of the raw materials in the embodiment are as follows:
polyethylene 60
Wood flour 29
In another embodiment of the present invention, the gear pump 5 includes a gear pump housing 51, two gear shafts 52 are disposed in the gear pump housing 51, the two gear shafts 52 are disposed in parallel and engaged with each other, a second gear shaft 522 is disposed under a first gear shaft 521, an upper end of the gear pump housing 51 is used as an input end and is communicated with the connector 3, as shown in fig. 4, the gear pump housing 51 is provided with a vertical second cavity, an upper end thereof is connected with the flow divider, a gear shaft is disposed under the flow divider in the gear pump housing 51, the two gear shafts are arranged along a vertical direction, i.e. along an entering direction of the melt, the first gear shaft 521 is used as a driving wheel and is connected with the gear pump driving assembly 54 through a universal coupling 53, specifically, the asynchronous motor is driven through a frequency converter, a reduction box and a transmission mechanism, and the speed is adjustable, the first gear shaft 521 is driven by the first gear shaft to rotate in a meshed manner, large bubbles in the melt from the upper end of the first gear shaft are converted into small bubbles by the cooperation of the first gear shaft and the second gear shaft, the small bubbles are not easy to release, gas is favorably and uniformly mixed in the melt, the lower end of the gear pump shell 51 serves as an output end and is communicated with the injection cylinder precursor 62, and the mixed melt enters the injection cylinder precursor.
The structural design of the gear pump enables the melt to be mixed more fully under the rotating shearing action of the gear shaft.
In another embodiment of the present invention, the check valve 7 includes a valve housing 71 and a ball 72, a top end of the valve housing 71 is set as an input end, a bottom end of the valve housing 71 is set as an output end, and the ball 72 adapted to the output port is disposed in the valve housing 71; can effectively prevent the reverse flow impact during injection.
Supercritical gas is fed into an injector through an external metering pump, the injector is injected into a first cavity 31, the supercritical gas, a polymer melt and a wood powder polymer are preliminarily mixed through a shuttle valve to form a supercritical fluid wood-plastic melt polymer, the melt molecular chain structure is broken up through the rotary shearing of an internal gear pump to be fully mixed with supercritical gas molecules, large bubbles are changed into small bubbles under the action of the rotary shearing and are not easy to release, and the supercritical gas of the melt polymer, the wood powder and the small bubbles is coupled and wrapped to form a stable melt polymer; and (3) injecting the polymer into a mold cavity, and completing product molding through low-pressure filling and gas bubble growing until the mold cavity is filled. The gas injection port, namely a supercritical fluid injector, is positioned at the front end of the flow divider, and the rear end of the internal gear pump is provided with a one-way valve device to prevent reverse flow impact during injection.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined, without conflict, by one skilled in the art
And (4) merging and combining.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A wood-plastic physical micro-foaming extrusion injection molding machine comprises a double-screw extruder (1) and an injection mechanism (6), and is characterized in that the double-screw extruder (1) comprises a charging barrel (11), two screws (12) are arranged in the charging barrel (11), the two screws (12) are arranged in parallel and are mutually meshed, a hopper (13) is arranged at the input end of the charging barrel (11), a charging barrel precursor (2) is arranged at the output end of the charging barrel (11), a connecting body (3) is arranged below the charging barrel precursor (2), a supercritical fluid injector (4) is arranged at the side end of the connecting body (3), a first cavity (31) is arranged in the connecting body (3), the upper end of the connecting body (3) is communicated with the charging barrel precursor (2) through the first cavity (31), the side end of the connecting body (3) is communicated with the supercritical fluid injector (4) through the first, a gear pump (5) is arranged below the connecting body (3), the injection mechanism (6) comprises an injection oil cylinder (61), an injection cylinder precursor (62) and a nozzle (63), the front end of the injection oil cylinder (61) is connected with the injection cylinder precursor (62), the front end of the injection cylinder precursor (62) is connected with the nozzle (63), and the top end of the injection cylinder precursor (62) is connected below the gear pump (5) through a check valve (7).
2. The wood-plastic physical micro-foaming extrusion injection molding machine according to claim 1, wherein the twin-screw extruder (1) and the injection mechanism (6) are arranged in parallel, and the injection mechanism (6) is arranged right below the twin-screw extruder (1).
3. The wood-plastic physical micro-foaming extrusion injection molding machine according to claim 1, wherein the first cavity (31) is vertically hollow, a flow divider (8) is arranged in the first cavity (31), the flow divider (8) is arranged at the middle lower part of the first cavity (31), a preset distance is reserved between the top end of the flow divider (8) and the upper wall of the first cavity (31), a connecting port of the supercritical fluid injector (4) and the first cavity (31) is arranged above the flow divider (8) in the first cavity (31), and the lower end of the flow divider (8) protrudes out of the connecting body (3) and is inserted into the gear pump (5).
4. The wood-plastic physical micro-foaming extrusion injection molding machine according to claim 3, wherein the flow divider (8) comprises a cylindrical part (81) and conical parts (82) arranged at two ends of the cylindrical part (81), at least one annular groove (83) is formed in the surface of the cylindrical part (81) along the circumferential direction of the cylindrical part, a preset number of strip-shaped grooves (84) are further formed in the surfaces of the cylindrical part (81) and the conical parts (82), each strip-shaped groove (84) is communicated with each annular groove (83), the strip-shaped grooves (84) in the surface of the conical parts (82) are converged at the end of the conical parts (82), the annular grooves (83) divide the flow divider (8) into at least two parts, and the strip-shaped grooves (84) in the surface of the flow divider (8) in the adjacent parts are staggered in the vertical direction.
5. The wood-plastic physical micro-foaming extrusion injection molding machine according to claim 1, wherein the gear pump (5) comprises a gear pump housing (51), two gear shafts (52) are arranged in the gear pump housing (51), the two gear shafts (52) are arranged in parallel in a horizontal manner and are meshed with each other, the second gear shaft (522) is arranged right below the first gear shaft (521), the upper end of the gear pump housing (51) is communicated with the connector (3) as an input end, and the lower end of the gear pump housing (51) is communicated with the injection cylinder precursor (62) as an output end.
6. The wood-plastic physical micro-foaming extrusion injection molding machine according to claim 1, wherein the check valve (7) comprises a valve housing (71) and a ball body (72), the top end of the valve housing (71) is provided as an input end, the bottom end of the valve housing (71) is provided as an output end, and the ball body (72) matched with the output end is arranged in the valve housing (71).
7. A molding process using the injection molding machine according to claim 1, characterized by comprising the steps of:
1) the raw materials comprise mixed powder consisting of polyethylene, wood powder and additives and supercritical gas;
2) heating and uniformly mixing the mixed powder, cooling, feeding the mixed powder into a charging barrel through a hopper, and mixing, plasticizing and extruding in a double-screw extruder to obtain a melt;
3) the melt enters the connecting body through the barrel precursor and is preliminarily mixed with the supercritical gas from the supercritical fluid injector in the first cavity;
4) the melt and the supercritical fluid are uniformly mixed under the action of a gear pump to obtain a stable melt polymer;
5) and injecting the melt polymer into a mold cavity, and completing product molding through low-pressure filling and gas bubble growing until the mold cavity is filled.
8. The molding process according to claim 7, wherein the additive is composed of a toner, a coupling agent, an internal lubricant, and an external lubricant.
9. The molding process according to claim 8, wherein the raw materials comprise, by weight:
polyethylene 50-60
29-44 parts of wood powder
Toner 1-2
Coupling agent 3-5
0.5-1 part of internal lubricant
External lubricant 0.5-1
1-2 parts of supercritical gas.
10. The molding process according to claim 8, wherein the coupling agent is maleic anhydride, the internal lubricant is stearic acid, the external lubricant is PE wax, and the supercritical gas is nitrogen or carbon dioxide.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111761774A (en) * | 2020-07-08 | 2020-10-13 | 合肥铂特精密工具有限公司 | Polyurethane plate foaming forming process |
| CN111761774B (en) * | 2020-07-08 | 2021-09-28 | 哈尔滨久安福新型保温材料有限公司 | Polyurethane plate foaming forming process |
| CN114773870A (en) * | 2022-04-07 | 2022-07-22 | 安徽森泰木塑集团股份有限公司 | Wood-plastic raw material with plasticizing capacity, preparation method thereof, wood-plastic master batch containing raw material and wood-plastic floor base material |
| CN114773870B (en) * | 2022-04-07 | 2023-02-28 | 安徽森泰木塑集团股份有限公司 | Wood-plastic raw material with plasticizing capacity, preparation method thereof, wood-plastic master batch containing raw material and wood-plastic floor base material |
| CN115782030A (en) * | 2023-01-30 | 2023-03-14 | 常州市第一橡塑设备有限公司 | Automatic feeding equipment of supercritical foaming forming machine |
| CN116176086A (en) * | 2023-04-24 | 2023-05-30 | 济南市阿波罗木塑复合材料有限公司 | Wood-plastic micro-foaming composite material for cold chain container board and preparation method thereof |
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