Injection molding machine and production process for EPP molding product production line

Abstract

The present application provides an injection molding machine and a production process for an EPP molding product production line, including a reaction tank, a screw extruder, a post-treatment system, and a molding system connected in sequence; a pre-expansion mixing system is arranged on the screw extruder; a gas foaming agent inlet is arranged on the pre-expansion mixing system, and the pre-expansion mixing system is connected to a gas generator through the gas foaming agent inlet. By adding a pre-expansion mixing system to the screw extruder and connecting a gas generator at the gas foaming agent inlet of the pre-expansion mixing system, the number of bubbles is further increased, so that the bubbles are more evenly distributed throughout the polypropylene material, thereby improving the product quality and making it more suitable for applications in some occasions with higher appearance requirements or larger load-bearing requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of injection molding, and in particular relates to an injection molding machine and a production process for an EPP molding product production line. Background Art

[0002] High-performance polypropylene, referred to as EPP, is mainly used for mold molding into various shapes and sizes, making it widely used in various fields such as packaging cushioning materials, agricultural and fishery containers, food tableware, building insulation materials and handicrafts.

[0003] The existing EPP molding technology generally adds a mechanical stirrer before the injection machine feed port, uses mechanical stirring to inject air into the liquid material, and finally solidifies into EPP. However, the use of mechanical stirring foaming has the disadvantages of cumbersome operation, low mixing efficiency, and uneven mixing.

[0004] Therefore, an EPP molding product production line was developed. EPP beads were produced by chemical methods. First, foaming pretreatment was carried out, and then the mixture was conveyed to a screw extruder for extrusion and granulation. The obtained material was then added to the reactor of the post-treatment system and kept warm at 175°C for 6 hours to obtain EPP porous particles.

[0005] Finally, the staff transported the obtained EPP porous particles to the molding system (injection machine).

[0006] The injection machine injects the preheated EPP particles into the molding mold through heating and pressure, and obtains the EPP molded product through mold molding, cooling and solidification, and demolding.

[0007] However, before the EPP porous particles are transported to the injection molding machine, the particles are prone to stratification or aggregation during transportation, resulting in insufficient bubbles in the injection molding machine, causing uneven density of the molded product, and thus affecting the quality stability of the product.

[0008] Patent application No.: 202410495798.5 discloses an injection molding machine and production process for an EPP molding product production line. The production steps are:

[0009] 1. Put the pre-foamed polypropylene particles into a reaction tank, add a foaming agent, raise the temperature to 145-156°C and the pressure to 3.0-5.0MPa in a carbon dioxide atmosphere, and conduct a preliminary reaction to form a polypropylene foam mixture with a certain expansion property;

[0010] 2. Carbon dioxide is transported into the gas generator through its air inlet, and the carbon dioxide is dispersed by the gas generator to decompose it into multiple groups of tiny bubbles, which are then sprayed into the pre-mixing system through the nozzle;

[0011] 3. Transport the obtained mixture into the pre-expansion mixing system and mix it with multiple groups of microbubbles. After uniform mixing, a mixed material is obtained.

[0012] 4. Then transport the mixed material into a screw extruder for extrusion granulation.

[0013] 5. After that, add the obtained material into the reaction kettle of the post-treatment system and keep it warm at a temperature of 175 °C for 6 hours to obtain EPP porous particles.

[0014] 6. Transport the obtained EPP porous particles into the forming system. The forming system can use common equipment on the market to obtain EPP formed products.

[0015] In the patent publication number: CN 101585924 B, an EPP polypropylene foamed bead production line is disclosed, which is characterized in that: each device or system is connected in sequence as follows: low-temperature mixing system → sealed leak-proof feeder → twin-screw extruder → underwater pelletizing system → first deep drying system → plasma fluidized bed reactor → water-soluble reaction system → second deep drying system → surface treatment mixing system → finished product bin and packaging system. A gas foaming agent injection port is provided on the twin-screw extruder; a plasma reaction device and an inert gas injection device are configured on the plasma fluidized bed of the plasma fluidized bed reactor; the water-soluble reaction system includes a water-soluble reaction kettle, and the water-soluble reaction kettle has an auxiliary low-temperature liquid medium injection port and a liquid foaming agent inlet. The EPP pre-expanded beads produced by the production line of the above technical solution have a uniform carbon dioxide content and stable product quality. However, adopting the above technical solution requires the introduction of more equipment (such as: fluidized bed reactor, etc.), resulting in a significant increase in production costs and maintenance costs, making it difficult to promote and use on a large scale in some small and medium-sized enterprises.

[0016] In view of this, how to solve the defects existing in the above technical solution has become one of the problems to be solved urgently in the field of injection molding technology. Summary of the Invention

[0017] Aiming at the deficiencies of the existing technology, the purpose of the embodiments of the present invention is to provide an injection molding machine and a production process for an EPP formed product production line to solve the problems in the above background technology.

[0018] To achieve the above purpose, the present invention provides the following technical solutions, including:

[0019] The injection molding machine body of the forming system;

[0020] A nozzle for injecting a liquid mixture into the forming mold system, which is arranged on the injection molding machine body.

[0021] The injection molding machine body is provided with a housing, and

[0022] a feed bin is arranged on the injection molding machine body,

[0023] a screw is arranged in the housing,

[0024] a third spiral blade and the first spiral blade are sequentially arranged along the radial extension direction of the screw near one end of the drive system of the injection molding machine body, and

[0025] the diameters gradually decrease;

[0026] an injection foamer is arranged on the housing at a position adjacent to the third spiral blade and the first spiral blade, and

[0027] the injection foamer is provided with a protective housing, and

[0028] an air inlet connection end is arranged on the protective housing,

[0029] the other end of the injection foamer is provided with an air jet opening, and

[0030] extends into the injection molding machine body.

[0031] Optionally, the diameter of the third spiral blade is 5 mm - 16 mm;

[0032] the depth of the spiral groove of the third spiral blade is 2.5 mm - 12.3 mm;

[0033] the diameter of the first spiral blade is 1.5 mm - 7.5 mm;

[0034] the depth of the spiral groove of the first spiral blade is 0.5 mm - 7.3 mm.

[0035] Optionally, the injection foamer is provided with a hydraulic cylinder, and

[0036] the hydraulic cylinder is installed on the housing, and

[0037] the extending end of the hydraulic cylinder extends into the protective housing, and

[0038] a connecting rod is installed at the extending end of the hydraulic cylinder located in the protective housing, and

[0039] a sealing end is arranged at the bottom end of the connecting rod, and

[0040] the side wall of the sealing end abuts against the inner wall of the injection foamer.

[0041] Optionally, it includes a reaction tank, a screw extruder, a post-treatment system and a forming system that are sequentially connected, and

[0042] The molding system includes an injection molding machine body as described in any one of claims 1 to 3,

[0043] The molding system further includes a molding die system 15,

[0044] Characterized in that it further includes:

[0045] A pre-expansion mixing system provided on the screw extruder;

[0046] A gas blowing agent inlet provided on the pre-expansion mixing system, and the pre-expansion mixing system is connected to a gas generator through the gas blowing agent inlet;

[0047] A liquid blowing agent inlet provided on the pre-expansion mixing system.

[0048] Optionally, the discharge port of the post-treatment system is connected to a conveying pipeline, and

[0049] is connected to the feed bin of the injection molding machine body through the conveying pipeline;

[0050] The gas generator is provided with a mixing zone,

[0051] An air inlet is provided on the mixing zone,

[0052] A connecting piece is provided at the outlet end of the mixing zone, and

[0053] is connected to a spray head through the connecting piece,

[0054] The spray head extends into the pre-expansion mixing system.

[0055] Optionally, the spray head is provided with two sets of separable first and second shells up and down,

[0056] A sealing ring and a sealing gasket are provided between the second shell and the first shell,

[0057] At least one set of through holes are provided on the sealing gasket;

[0058] One end of the second shell far from the mixing zone is provided with a disc, and

[0059] The disc is integrally provided with the second shell,

[0060] At least one set of through holes are provided on the disc.

[0061] Optionally, a second vaporizer is provided inside the first shell;

[0062] A shaft is provided on the second vaporizer, and

[0063] A connector is installed on the shaft, and

[0064] the first housing is connected through the connector;

[0065] A seal is fixedly installed on the second vaporizer near the shaft position, and

[0066] it is installed on the first housing,

[0067] A first vaporizer is arranged on one side of the second vaporizer, and

[0068] the first vaporizer and the first vaporizer are arranged side by side vertically;

[0069] A second air hole is formed in the second vaporizer, and

[0070] a first air hole is formed in the first vaporizer,

[0071] the first air hole and the second air hole are arranged corresponding to each other.

[0072] Optionally, the connector is provided with a positioning rod, and

[0073] the positioning rod is divided into a smooth end and a threaded end,

[0074] wherein the smooth end is the connecting end, and

[0075] the connecting end is connected to the shaft through a pin shaft;

[0076] the threaded end of the positioning rod is threadedly installed in the first housing, and

[0077] its position is fixed through a fastener.

[0078] Optionally, a cutting system is arranged in the mixing area,

[0079] the cutting system is provided with a driving system,

[0080] a driving shaft of the driving system is connected to a rotating shaft, and

[0081] a first cutting member is obliquely installed on the rotating shaft in a fixed connection manner,

[0082] the inclination angle is 12°,

[0083] at least two groups of second cutting members are installed on the first cutting member, and

[0084] the distance between adjacent two groups of second cutting members is 16 - 33 μm.

[0085] Optionally, the production process, the specific steps are:

[0086] (1) Put the pre-expanded polypropylene particles into the reaction tank 1, add the foaming agent, and under a carbon dioxide atmosphere, raise the temperature to 145 - 156 °C and increase the pressure to 3.0 - 5.0 MPa to carry out a preliminary reaction to form a mixture with a certain degree of expansibility;

[0087] (2) Transport carbon dioxide into the gas generator through its air inlet, disperse the carbon dioxide by the gas generator to decompose it into multiple groups of tiny bubbles, and spray it into the pre-expansion mixing system through the nozzle;

[0088] (3) Transport the obtained mixture into the pre-expansion mixing system 3 and mix it with multiple groups of tiny bubbles. After mixing evenly, obtain the mixed material;

[0089] (4) Then transport the mixed material into the screw extruder 4 for extrusion granulation;

[0090] (5) Then add the obtained material into the reaction kettle of the post-treatment system 5 and keep it warm at 175 °C for 6 hours to obtain the EPP porous particles;

[0091] (6) Transport it into the interior of the injection molding machine body through the post-treatment system;

[0092] (7) Then input bubbles into the injection molding machine through the injection foamer;

[0093] (8) Finally, input the liquid containing bubbles into the molding die system through the injection molding machine, cure and cool, and demold to obtain the EPP molded product.

[0094] In summary, the beneficial effects of the present invention are:

[0095] (1) By the combined use of the pre-expansion mixing system and the injection foamer in the present invention, the bubbles can be evenly distributed in the molten liquid mixture, thereby greatly increasing the density of the product and improving the strength of the product.

[0096] (2) By adding an injection foamer, first input gas into the injection foamer through the air inlet connection end 1433. At this time, start the hydraulic cylinder, and use the extending end of the hydraulic cylinder to drive the sealing end 1437 of the connecting rod to move in the injection foamer. Then, use the downward movement of the sealing end to compress the volume of the gas in the injection foamer, thereby forming a stronger pressure, so that when the gas is ejected through the jet orifice, smaller bubbles can be formed, making the gas more evenly distributed in the EPP melt, increasing the density of the molded product, and thus improving the quality of the product.

[0097] (3) By adding a pre-expansion mixing system to the screw extruder and connecting a gas generator to the gas foaming agent inlet of the pre-expansion mixing system, the number of its bubbles is further increased, making the bubbles more evenly distributed throughout the polypropylene material, thereby improving product quality and making it more suitable for applications in some occasions with high appearance requirements or large load-bearing requirements.

[0098] (4) In actual application, when the gas in the mixing zone shoots into the cavity at high speed through the through holes, and at the same time, since the first housing and the second housing are hermetically connected, a sealing ring and a sealing gasket are provided between the second housing and the first housing, thereby greatly improving the sealing performance, and then increasing the air pressure in the cavity. At this time, the high-pressure air flow passes through the through holes on the sealing gasket for secondary pressurization and shoots into the first vaporizer and the second vaporizer at a high speed; numerous tiny bubbles are formed through the air holes of the two vaporizers, making the distribution more uniform in the material.

[0099] (5) When it is necessary to change the amount of carbon dioxide ejected, by loosening the fastening screw to release the restriction between the second vaporizer and the first housing, then by loosening the fastener and rotating the positioning rod to drive the shaft to rotate, and then driving the second vaporizer to rotate. Since the position of the first vaporizer is fixed, the overlapping area between the second air hole and the first air hole can be changed, thereby changing the amount of carbon dioxide ejected through the nozzle to meet the requirements in some occasions with high appearance requirements or large load-bearing requirements, and improving the strength and stiffness of the EPP structure. Description of the Drawings

[0100] Figure 1 Schematic diagram of the overall structure provided by an embodiment of the injection molding machine and production process for the EPP molding product production line of the present invention;

[0101] Figure 2 Schematic diagram of the gas generator structure provided by an embodiment of the injection molding machine and production process for the EPP molding product production line of the present invention;

[0102] Figure 3 For the present invention Figure 2 Schematic diagram of the structure of the nozzle shown in;

[0103] Figure 4 For the present invention Figure 2 Schematic diagram of a partial structure shown in;

[0104] Figure 5 For the present invention's Figure 3 Exploded view of the nozzle shown in;

[0105] Figure 6 For the present invention Figure 2Schematic diagram of the structure at the second housing position shown in

[0106] Figure 7 For the present invention Figure 5 Two-dimensional assembly drawing of the first vaporizer and the second vaporizer shown in

[0107] Figure 8 Schematic diagram of the cutting system structure provided for an injection molding machine and a production process according to an embodiment of the injection molding machine for an EPP molding product production line of the present invention

[0108] Figure 9 Overall structure schematic diagram of the injection molding machine body provided for an injection molding machine and a production process according to an embodiment of the injection molding machine for an EPP molding product production line of the present invention

[0109] Figure 10 Partial structure schematic diagram of the injection molding machine body provided for an injection molding machine and a production process according to an embodiment of the injection molding machine for an EPP molding product production line of the present invention

[0110] Figure 11 Schematic diagram of the injection foamer provided for an injection molding machine and a production process according to an embodiment of the injection molding machine for an EPP molding product production line of the present invention

[0111] Reference numerals:

[0112] 1. Reaction tank

[0113] 2. Gas generator; 021. Drive system; 022. Air inlet

[0114] 023. Mixing zone; 0231. Connecting piece

[0115] 024. Nozzle; 0241. Fastening connecting piece; 0242. Cavity; 0243. First vaporizer; 0244. First air hole; 0245. Second vaporizer; 0246. Second air hole; 0247. First housing

[0116] 0248. Sealing gasket; 02481. Through hole

[0117] 0249. Sealing ring

[0118] 3. Pre-expanded mixing system

[0119] 4. Screw extruder

[0120] 5. Post-treatment system; 051. Conveying pipeline

[0121] 7. Second housing; 071. Limiter; 072. Positioning groove; 074. Disc; 075. Through hole

[0122] 081. Connecting end; 083. Positioning rod; 804. Fastener;

[0123] 9. Cutting system; 091. Driving system; 092. Rotating shaft; 093. First cutting piece; 094. Second cutting piece;

[0124] 10. Shaft;

[0125] 11. Seal;

[0126] 12. Fastening screw;

[0127] 13. Feed bin;

[0128] 14. Injection molding machine body;

[0129] 141. Nozzle;

[0130] 142. Housing;

[0131] 143. Injection foamer; 1431. Hydraulic cylinder; 1432. Protective housing; 1433. Air inlet connecting end; 1434. Screw rod; 1435. Jet port; 1436. Connecting rod; 1437. Sealed end;

[0132] 1444. Screw; 1441. First helical blade; 1442. Third helical blade; 1443. Third helical blade; 15. Molding die system. Detailed implementation mode

[0133] In the description of this specification, the description referring to terms such as "certain embodiments", "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0134] In the present invention, the terms "first", "second", and "third" are used only for descriptive purposes and should not be construed as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "joined" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0135] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Although exemplary embodiments are disclosed in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the concept of the present invention to those skilled in the art.

[0136] Please refer to Figures 1 to 11 As shown, an embodiment of the present invention provides an injection molding machine and a production process for an EPP molding product production line, including a reaction tank 1, a screw extruder 4, a post-treatment system 5, and a molding system connected in sequence; by putting polypropylene pre-expanded particles into the reaction tank 1, adding a foaming agent, and heating to 145-156 °C and pressurizing to 3.0-5.0 MPa in a carbon dioxide atmosphere, a preliminary reaction is carried out to form a mixture with a certain expansibility.

[0137] Further, a material inlet and a pre-expansion mixing system 3 are provided on the screw extruder 4. The material inlet is connected to the outlet of the reaction tank 1 through a pipeline, and the mixture is input through the material inlet.

[0138] A liquid foaming agent inlet and a gas foaming agent inlet are provided on the pre-expansion mixing system 3, and the gas foaming agent inlet is connected to a gas generator 2. The gas generator 2 is provided with a mixing zone 023. An air inlet 022 is opened on the mixing zone 023, and the air inlet 022 is connected to an external gas production device. The gas production device can be a gas compression and transportation system; a nozzle 024 is installed at the outlet end of the mixing zone 023, and the nozzle 024 extends into the pre-expansion mixing system 3. In this embodiment, the nozzle 024 is obliquely inserted into the gas foaming agent inlet and extends into the pre-expansion mixing system 3, and the connection position between the nozzle 024 and the gas foaming agent inlet of the pre-expansion mixing system 3 is hermetically connected.

[0139] A cutting system 9 is provided in the mixing zone 023 and is driven by a driving system 091.

[0140] In this embodiment, a pre-foaming mixing system 3 is added to the screw extruder 4, and a gas generator 2 is connected to the gas blowing agent inlet of the pre-foaming mixing system 3, thereby further increasing the number of its bubbles, making the bubbles more evenly distributed throughout the polypropylene material, improving the product quality, and making it more suitable for applications in some occasions with high appearance requirements or large load-bearing requirements.

[0141] Furthermore, a connecting piece 0231 is provided at the outlet end of the mixing zone 023, and the spray head 024 is connected through the connecting piece 0231. The connecting piece 0231 and the mixing zone 023 are detachably connected. In this embodiment, the spray head 024 is facilitated to be replaced by adding the connecting piece 0231.

[0142] Please refer to Figure 5 As shown, the spray head 024 is provided with upper and lower groups of separable first shells 0247 and second shells 7, and the first shell 0247 and the second shell 7 are hermetically connected. A sealing ring 0249 and a sealing gasket 0248 are arranged between the second shell 7 and the first shell 0247 to improve the sealing performance. At least one group of through holes 02481 are provided on the sealing gasket 0248. By providing the through holes 02481 on the sealing gasket 0248, the speed of the gas injected into the second shell 7 is increased.

[0143] Furthermore, a disk 074 is provided at one end of the second shell 7 away from the mixing zone 023, and the disk 074 and the second shell 7 are integrally formed. At least one group of through holes 075 are provided on the disk 074.

[0144] In this embodiment, by providing at least one group of through holes 075 on the disk 074, the gas in the mixing zone 023 can penetrate through the through holes 075 at a high speed and be injected into the first shell 0247.

[0145] In actual application, when the gas in the mixing zone 023 penetrates through the through holes 075 at a high speed and is injected into the cavity, and at the same time, since the first shell 0247 and the second shell 7 are hermetically connected, and a sealing ring 0249 and a sealing gasket 0248 are arranged between the second shell 7 and the first shell 0247, the sealing performance is greatly improved, and the air pressure in the cavity is increased. At this time, the high-pressure air flow passes through the through holes 02481 on the sealing gasket 0248. Since the aperture of the through holes 02481 is small, it is pressurized again and injected into the first vaporizer and the second vaporizer at a high speed; numerous tiny bubbles are formed through the air holes of the two vaporizers.

[0146] In this embodiment, since most of the carbon dioxide in the existing EPP structure is introduced into the material by mechanical means, but there are a series of defects in the existing mechanical means. When EPP is applied in different occasions, such as in some occasions with high appearance requirements or large load-bearing requirements, such as; when applied in refrigerator products or automotive parts, if the number of bubbles in the EPP is small, the strength and stiffness of the produced EPP structure cannot meet the corresponding standards. In order to make the corresponding products meet the above requirements, manufacturers have added a series of equipment such as fluidized beds and drying systems. However, this greatly increases the input cost and energy consumption, and is not suitable for application in small and medium-sized enterprises. To solve the above defects, please refer to Figures 1 to 7 As shown, a limiter 071 is provided on the disc 074, and a positioning groove 072 is provided in the limiter 071, and the positioning groove can be used to place the shaft 10;

[0147] A second vaporizer 0245 is provided in the first housing 0247; and a shaft 10 is provided on the second vaporizer 0245. The other end of the shaft 10 can extend into the positioning groove 072, and a connector is installed on the shaft 10, and the first housing 0247 is connected through the connector. Further, in practical applications, two sets of the connectors can be used;

[0148] A seal 11 is fixedly installed on the second vaporizer 0245 near the position of the shaft 10, and is fixedly installed on the first housing 0247 through a fastening screw 12 to realize the fixed connection between the first housing 0247 and the second vaporizer 0245. A first vaporizer 0243 is provided on one side of the second vaporizer 0245, and the first vaporizer 0245 and the first vaporizer 0243 are arranged side by side vertically.

[0149] Further, a second air hole 0246 is provided on the second vaporizer 0245, and a first air hole 0244 is provided on the first vaporizer 0243, and the first air hole 0244 and the second air hole 0246 are arranged corresponding to each other.

[0150] Further, the connector is provided with the positioning rod 083, and the positioning rod 083 is divided into a smooth end and a spiral blade. The smooth end is the connecting end 081, and the connecting end 081 is connected to the shaft 10 through a pin shaft, so that by rotating the positioning rod 083, the shaft 10 can be driven to rotate, and then the second vaporizer 0245 can be driven to rotate.

[0151] Further, the spiral blade of the positioning rod 083 is installed in the first housing 0247 for thread fitting, and the position is fixed through a fastener 084. The fastener 084 is preferably a fastening nut.

[0152] In this embodiment, those skilled in the art should be able to understand that when it is necessary to change the amount of carbon dioxide ejected, by loosening the fastening screw, the restriction between the second vaporizer 0245 and the first housing 0247 is released. Then, by loosening the fastener 084 and rotating the positioning rod 083, the shaft 10 is driven to rotate, and then the second vaporizer 0245 is driven to rotate. Since the position of the first vaporizer is fixed, the overlapping area between the second air hole 0246 and the first air hole 0244 can be changed, and thus the amount of carbon dioxide ejected through the nozzle can be changed to meet the requirements in some occasions with higher appearance requirements or larger load-bearing requirements, such as in refrigerator products or automotive parts, so as to improve the strength and stiffness of the EPP structure.

[0153] Please refer to Figure 1 and Figure 8 As shown, the cutting system 9 is provided with a driving system 091. The driving system 091 is preferably a rotary motor. The driving system 091 is fixedly installed on the outer wall of the mixing zone 023 through fastening bolts. The driving shaft of the driving system 091 is connected to the rotating shaft 092 through a bearing assembly, and a first cutting member 093 is obliquely installed on the rotating shaft 092 by a fixed connection method, and the inclination angle is 12°. At least two groups of second cutting members 094 are installed on the first cutting member 093 by a fixed connection method, and the distance between adjacent two groups of second cutting members 094 is 16 - 33 μm, preferably 23 μm.

[0154] In this embodiment, when the driving system is started, the driving system drives the first cutting member and the second cutting member on the shaft to rotate at a high speed to generate a shearing force, and the carbon dioxide is split into smaller carbon dioxide by the generated shearing force, further increasing the amount of carbon dioxide.

[0155] When the distance between adjacent two groups of second cutting members 094 is 23 μm, when the two cutting members (the first cutting member and the second cutting member) rotate, more carbon dioxide is formed and the size is more suitable.

[0156] Since most existing devices use mechanical stirring for foaming, which has the disadvantages of cumbersome operation, low mixing efficiency, and uneven mixing. To solve the above defects, first, uniformly mixed EPP porous particles with a relatively high content of bubbles are prepared. Then, the staff transports the obtained EPP porous particles into the molding system (injection machine). The injection machine injects the preheated EPP particles into the molding die through heating and pressure, and through die molding, cooling and solidification, and demolding, an EPP molded product with relatively high strength and stiffness is obtained. However, with the above technical solution, it is necessary to first prepare EPP porous particles and then transport the EPP porous particles into the molding system. Before being transported to the injection molding machine, the particles are prone to stratification or aggregation during transportation, resulting in insufficient bubbles in the injection molding machine, uneven density of the molded product, and thus affecting the quality stability of the product.

[0157] For the above technical solution, to reduce the probability of stratification or aggregation of EPP porous particles before being transported to the injection molding machine, the post-treatment system and the feed bin 13 of the injection molding machine body 14 are directly connected through the conveying pipeline 051. Thus, the EPP porous particles can be directly transported into the feed bin 13 of the injection molding machine body 14, greatly reducing the probability of stratification or aggregation of the EPP porous particles. However, in the actual application process, affected by various factors such as conveying speed, pressure, conveying pipeline design and layout, it is still impossible to completely solve the problem of stratification or aggregation of EPP porous particles during transportation, resulting in over-compression or insufficient bubbles in the injection molding machine, uneven density of the molded product, and thus affecting the quality stability of the product. To solve the above technical problems, please refer to Figures 1 to 11 The molding system includes an injection molding machine body 14 and a molding die system 15. The post-treatment system 5 is an existing technology and will not be described in detail here. The discharge port of the post-treatment system 5 is connected to the conveying pipeline 051 and is connected to the feed bin 13 of the injection molding machine body 14 through the conveying pipeline 051.

[0158] In this embodiment, to reduce the probability of stratification or aggregation of EPP porous particles before being transported to the injection molding machine, the post-treatment system and the feed bin 13 of the injection molding machine body 14 are directly connected through the conveying pipeline 051. Thus, the EPP porous particles can be directly transported into the feed bin 13 of the injection molding machine body 14, greatly reducing the probability of stratification or aggregation of the EPP porous particles.

[0159] In the above technical solution, in order to reduce the probability of stratification or aggregation of EPP porous particulate matter before it is transported to the injection molding machine, the post-treatment system and the feed bin 13 of the injection molding machine body 14 are directly connected through the transport pipeline 051. As a result, the EPP porous particulate matter can be directly transported into the feed bin 13 of the injection molding machine body 14, thereby greatly reducing the probability of stratification or aggregation of the EPP porous particulate matter. However, in the actual application process, affected by various factors such as the transport speed, pressure, design and layout of the transport pipeline, it is still impossible to completely solve the problem of stratification or aggregation of the EPP porous particulate matter during transportation. As a result, there are situations of over-compression or insufficient bubbles in the injection molding machine, leading to uneven density of the molded product and affecting the quality stability of the product. To solve the above problems, please refer to Figures 9 to 11 As shown, the injection molding machine body 14 is provided with a nozzle 141. The liquid mixture is injected into the molding die system 15 through the nozzle 141, and the EPP molded product is finally obtained through mold forming, cooling and solidification, and demolding by using the molding die system 15;

[0160] The injection molding machine body 14 adopts a screw-type injection molding machine. By the rotation and pushing of the screw, the EPP porous particulate matter is gradually pushed towards the heating area of the injection molding machine body 14, and the EPP porous particulate matter is heated to a molten state.

[0161] Further, the injection molding machine body 14 is provided with a housing 142, and a screw 144 is arranged inside the housing 142. The screw 144 is driven by the drive system (not annotated in the figure) of the injection molding machine body 14. Along the radial extension direction of the screw near one end of the drive system of the injection molding machine body, a third spiral blade 1443 and the first spiral blade 1441 are sequentially arranged on the screw 144, and their diameters gradually decrease;

[0162] The diameter of the third spiral blade 1443 is 5 mm - 16 mm; preferably 7 mm;

[0163] The depth of the spiral groove of the third spiral blade 1443 is 2.5 mm - 12.3 mm;

[0164] The diameter of the first spiral blade 1441 is 1.5 mm - 7.5 mm;

[0165] The depth of the spiral groove of the first spiral blade 1441 is 0.5 mm - 7 mm.

[0166] In this embodiment, the rotation of the screw drives the spiral blade to rotate, so that it can effectively push the EPP porous particulate matter during rotation, enabling it to be evenly mixed and heated.

[0167] Furthermore, an injection foamer 143 is provided on the housing 142 at a position adjacent to the third spiral blade 1443 and the first spiral blade 1441 , and an air outlet end of the injection foamer 143 extends into the body of the injection molding machine.

[0168] In this embodiment, an injection foamer 143 is provided on the shell 142 located at a position adjacent to the third spiral blade 1442 and the first spiral blade 1441, and then the present invention injects gas into the interior of the injection molding machine body 14 (located at a position adjacent to the third spiral blade 1442 and the first spiral blade 1441) through the injection foamer. Since the present invention sequentially provides the third spiral blade 1443, the third spiral blade 1442 and the first spiral blade 1441 with gradually decreasing diameters on the radially extending screw 144 of the screw at one end of the drive system 13 close to the injection molding machine body, the available space inside the injection molding machine body gradually increases. At this time, the pressure on the EPP porous particles in a molten state is relatively small, so it is convenient to inject gas, so that the gas is more effectively dissolved in the molten liquid.

[0169] Furthermore, the injection foamer 143 is provided with a protective shell 1432, and the protective shell 1432 is provided with an air inlet connection end 1433, and is connected to an external air supply device through the air inlet connection end 1433; and the other end of the injection foamer 143 is provided with a jet port 1435, through which gas is transported into the injection molding machine body.

[0170] The injection foamer 143 is provided with a hydraulic cylinder 1431, and the hydraulic cylinder 1431 is fixedly installed on the shell 142 by fastening screws. The hydraulic cylinder 1431 is preferably a telescopic hydraulic cylinder, and the protruding end of the hydraulic cylinder 1431 extends into the protective shell 1432, and the protruding end of the hydraulic cylinder 1431 located in the protective shell 1432 is fixedly installed with a connecting rod 1436 by fastening screws, and a sealing end 1437 is provided at the bottom end of the connecting rod 1436, and the side wall of the sealing end 1437 is in conflict with the inner wall of the injection foamer 143.

[0171] In this embodiment, an injection foamer is added, and gas is first input into the injection foamer through the air inlet connecting end 1433. At this time, the hydraulic cylinder is started and the sealing end 1437 of the connecting rod is driven to move in the injection foamer by the extended end of the hydraulic cylinder, and then the volume of the compressed gas in the injection foamer is compressed by the downward movement of the sealing end, thereby forming a stronger pressure, so that when the gas is ejected through the air jet, smaller bubbles can be formed, so that the gas is more evenly distributed in the EPP melt, thereby improving the density of the molded product and thus improving the quality of the product.

[0172] A production process for EPP molded products, the specific steps are as follows:

[0173] (1) Put polypropylene pre-expanded particles into reaction tank 1, add a foaming agent, and in a carbon dioxide atmosphere, heat up to 145 - 156 °C and increase the pressure to 3.0 - 5.0 MPa to carry out a preliminary reaction to form a mixture with a certain expandability;

[0174] (2) Transport carbon dioxide into the gas generator through its air inlet, disperse the carbon dioxide through the gas generator to decompose it into multiple groups of tiny bubbles, and spray it into the pre-expansion mixing system 3 through a nozzle;

[0175] (3) Transport the obtained mixture into the pre-expansion mixing system 3 and mix it with multiple groups of tiny bubbles. After mixing evenly, a mixed material is obtained;

[0176] (4) Then transport the mixed material into the screw extruder 4 for extrusion granulation;

[0177] (5) Then add the obtained material into the reaction kettle of the post-treatment system 5 and keep it warm at a temperature of 175 °C for 6 h to obtain EPP porous particles;

[0178] (6) Transport the obtained EPP porous particles into the post-treatment system and transport them into the injection molding machine body through the post-treatment system;

[0179] (7) Then input bubbles into the injection molding machine through an injection foamer;

[0180] (8) Finally, input the liquid containing bubbles into the molding die system through the injection molding machine. The molding die system can use common equipment on the market to obtain EPP molded products.

[0181] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. The EPP molding product production line is characterized in that, Including: A reaction tank, a screw extruder, a post-treatment system, and a forming system connected in sequence, and The forming system includes an injection molding machine body, The forming system further includes a forming mold system, A pre-expansion mixing system provided on the screw extruder; A gas blowing agent inlet provided on the pre-expansion mixing system, The pre-expansion mixing system is connected to a gas generator through the gas blowing agent inlet; A liquid blowing agent inlet provided on the pre-expansion mixing system; The discharge port of the post-treatment system is connected to a conveying pipeline, and Connected to the feed bin of the injection molding machine body through the conveying pipeline; The gas generator is provided with a mixing zone, and a cutting system is provided in the mixing zone, The cutting system is provided with a driving system, The drive shaft of the driving system is connected to a rotating shaft, and A first cutting member is obliquely installed on the rotating shaft by a fixed connection method, and at least two groups of second cutting members are installed on the first cutting member, with an inclination angle of 12°, The distance between adjacent two groups of second cutting members is 23 μm; An air inlet is provided on the mixing zone, A connecting member is provided at the outlet end of the mixing zone, and Connected to a spray head through the connecting member, The spray head is obliquely inserted into the gas blowing agent inlet and extends into the pre-expansion mixing system; The spray head is provided with an upper and a lower group of separable first housing and second housing, A sealing ring and a sealing gasket are provided between the second housing and the first housing, At least one group of through holes are provided on the sealing gasket; One end of the second housing far from the mixing zone is provided with a disc, and The disc is integrally provided with the second housing, At least one group of through holes are provided on the disc; A second vaporizer is provided in the first housing; A first vaporizer is provided on one side of the second vaporizer.

2. The EPP forming product production line according to claim 1, characterized in that A shaft is provided on the second vaporizer, and A connector is installed on the shaft, and Connected to the first housing through the connector; A sealing member is fixedly installed on the second vaporizer near the shaft position and Installed on the first housing, The first vaporizer and the second vaporizer are arranged side by side vertically; A second air hole is provided on the second vaporizer, and A first air hole is provided on the first vaporizer, The first air hole and the second air hole are arranged correspondingly.

3. The EPP forming product production line according to claim 2, characterized in that The connector is provided with a positioning rod, and The positioning rod is divided into a smooth end and a threaded end, Wherein the smooth end is the connecting end, and The connecting end is connected to the shaft through a pin shaft; The threaded end of the positioning rod is threadedly installed in the first housing and Position-fixed through a fastener.

4. The EPP forming product production line according to claim 1, characterized in that A nozzle for injecting a liquid mixture into the forming mold system is provided on the injection molding machine body, The injection molding machine body is provided with a housing, and A feed bin is provided on the injection molding machine body, A screw is provided in the housing, A third spiral blade and a first spiral blade are sequentially arranged along the radial extension direction of the screw at one end of the driving system close to the injection molding machine body, and The diameter gradually decreases; The diameter of the third helical blade is 16 mm; The depth of the helical groove of the third helical blade is 12.3 mm; The diameter of the first helical blade is 7.5 mm; The depth of the helical groove of the first helical blade is 7.3 mm An injection foamer is provided on the housing at a position adjacent to the third helical blade and the first helical blade, and The injection foamer is provided with a hydraulic cylinder; The hydraulic cylinder is installed on the housing; and The extending end of the hydraulic cylinder extends into the protective housing; A connecting rod is installed at the extending end of the hydraulic cylinder located within the protective housing; A sealing end is provided at the bottom end of the connecting rod; The side wall of the sealing end abuts against the inner wall of the injection foamer.

5. The EPP forming product production line according to claim 4, wherein The injection foamer is provided with a protective housing, and An air inlet connection end is provided on the protective housing, The other end of the injection foamer is provided with a jet port, and extends into the injection molding machine body.

Images