A pur in-mold spray-free apparatus

Abstract

The application discloses a kind of PUR in-mold free spraying equipment, it is related to the field of plastic forming, including A material raw material bucket, B material raw material bucket, for pumping raw material from A material raw material bucket and B material raw material bucket workstation, with the mixing head being connected with workstation, A material raw material bucket and workstation are sequentially connected first storage tank, first working tank, B material raw material bucket and workstation are sequentially connected second storage tank, second working tank;First storage tank, first working tank, second storage tank and second working tank are all provided with defoaming mechanism;Workstation includes two groups of pumping mechanism, is respectively used for A material from first working tank to the pumping of mixing head, B material from second working tank to the pumping of mixing head;Pumping mechanism includes sequentially connected booster pump, first filter, metering pump, second filter and flowmeter.The application is used to solve the problem of high product reject rate and low good product rate in the prior art of PUR material in-mold free spraying process, to achieve the purpose of improving product good product rate and reducing production cost.

Description

Technical Field

[0001] This invention relates to the field of plastic molding, and more specifically to an in-mold coating-free equipment for PUR. Background Technology

[0002] PUR (Polyurethane) is a class of polymer materials with diverse properties and wide applications. The conventional production process is to use a high-pressure mixing head to directly mix component A (white component, such as polyether) and component B (black component, such as polyisocyanate) under high pressure inside the mixing head.

[0003] In-mold coating (IMC) is an advanced manufacturing technology that integrates product molding and surface decoration. Its core idea is to simultaneously apply color or pattern decoration during injection molding or compression molding, eliminating the need for traditional secondary processing such as painting or electroplating. IMC has been increasingly applied to decorative plastics, such as automotive interior and exterior trim (e.g., A / B pillars, bumpers, grilles), consumer electronics (phone cases, phone back panels, laptop casings), and appliance panels.

[0004] However, in the existing technology, the in-mold coating-free process based on PUR material is still in the theoretical stage for domestic manufacturers. After extensive research, the applicant found that the main reasons restricting its promotion and application are: depending on the specific processing object, the forming thickness of the material inside the mold varies from micrometers to millimeters. Impurities, micro bubbles and visible bubbles in the raw materials can easily lead to low product yield and high scrap rate, which in turn leads to high production costs.

[0005] The aforementioned problems have all resulted in a low product yield, severely restricting the widespread application of in-mold coating-free technology in the decorative plastics industry. Summary of the Invention

[0006] This invention provides an in-mold coating-free equipment for PUR materials to solve the problems of high scrap rate and low yield in the in-mold coating-free process of PUR materials in the prior art, thereby achieving the goal of improving product yield and reducing production costs.

[0007] This invention is achieved through the following technical solution: A PUR in-mold coating-free equipment includes an A material tank, a B material tank, a workstation for pumping raw materials from the A material tank and the B material tank, and a mixing head connected to the workstation. The A material tank and the workstation are connected in sequence to a first storage tank and a first working tank, and the B material tank and the workstation are connected in sequence to a second storage tank and a second working tank. A degassing mechanism is installed in the first storage tank, the first working tank, the second storage tank, and the second working tank. The workstation includes two sets of pumping mechanisms, which are used for pumping material A from the first working tank to the mixing head and for pumping material B from the second working tank to the mixing head, respectively. The pumping mechanism includes a booster pump, a first filter, a metering pump, a second filter, and a flow meter connected in sequence.

[0008] To address the high scrap rate and low yield of PUR material in-mold coating-free processes in existing technologies, this application proposes an in-mold coating-free PUR equipment. The A-material raw material tank, B-material raw material tank, workstation, and mixing head can all utilize existing technologies. The first and second storage tanks in this application are used to temporarily store the two raw materials, and undergo a first degassing process via corresponding degassing mechanisms. The first and second working tanks directly supply the mixing head and participate in the raw material self-circulation, undergoing a second degassing process via corresponding degassing mechanisms. The two raw materials are pumped from the first and second working tanks to the mixing head via their respective pumping mechanisms. Those skilled in the art will understand that when casting is required, the two raw materials are mixed in the mixing head and output to the mold; during self-circulation, the two raw materials flow back from the mixing head to their respective working tanks. The movement of the two raw materials from their respective raw material tanks to their corresponding storage tanks, and from the storage tanks to their corresponding working tanks, can be achieved using any existing conveying method, without specific limitations.

[0009] This application employs a two-stage degassing process by incorporating degassing mechanisms in the first storage tank, the first working tank, the second storage tank, and the second working tank. This significantly reduces residual gas in the raw materials, overcoming problems such as rough product surfaces, poor smoothness, and unpleasant feel in existing technologies, thereby improving the yield rate. Furthermore, the working tank and its corresponding storage tank are used in pairs, with one in operation and the other on standby, ensuring sufficient time and space for degassing the raw materials. This facilitates continuous production and avoids downtime due to material shortages.

[0010] This application utilizes a booster pump in the pumping mechanism to pressurize and pump out materials A and B under negative pressure, and uses a metering pump as a secondary pumping device to pressurize the raw materials a second time while stabilizing the metering pump's stroke rate, ensuring that the raw materials after negative pressure degassing can be normally transported to the mixing head.

[0011] Furthermore, because the PUR in-mold coating-free process requires the mixed raw material to be injected into the mold at a low flow rate and with rapid propulsion, the needle valve at the mold inlet has an extremely small diameter (less than 1 mm). Particulate impurities in the raw material are prone to clogging it. Therefore, the pumping mechanism of this application incorporates a two-stage filtration system to gradually filter the raw material, significantly reducing interference from particulate impurities with downstream equipment and lowering the risk of clogging. In addition, the synergistic effect of the first and second filters further breaks down air bubbles within the raw material, thereby improving product quality. Moreover, the pressurization function of the metering pump compensates for the pressure drop caused by the two-stage filtration, ensuring that the raw material is stably delivered to the mixing head under high pressure.

[0012] Furthermore, the defoaming mechanism includes a negative pressure extraction device and several defoaming umbrella groups arranged vertically. The debubbling umbrella assembly includes an upper guide plate and a lower guide plate that are coaxially distributed vertically. The upper guide plate gradually slopes downward from the inside to the outside in the radial direction, and the lower guide plate gradually slopes downward from the outside to the inside in the radial direction. The outer diameter of the bottom end of the upper guide plate is smaller than the outer diameter of the top end of the corresponding lower guide plate. A flow channel is provided at the lower position of the lower guide plate.

[0013] This solution utilizes a negative pressure extraction device to maintain a negative pressure state within the first storage tank, first working tank, second storage tank, and second working tank, facilitating rapid removal of internal gases and improving the degassing effect on the raw materials. During operation, the raw materials enter from the top of the corresponding tank (storage tank or working tank) and flow sequentially from top to bottom through each degassing umbrella group. For any given degassing umbrella group, the upper guide plate is located above the corresponding lower guide plate. The raw materials first flow to the surface of the upper guide plate, then flow downwards and outwards along its surface. They then drip from the edge of the upper guide plate to the lower guide plate, flowing downwards and inwards along its surface, and finally dripping down from the lower guide plate's flow channel onto the next lower degassing umbrella group. The raw materials dripping from the bottommost degassing umbrella group enter the bottom area of ​​the corresponding tank.

[0014] The degassing mechanism of this solution, through the cooperation of a negative pressure extraction device and several degassing umbrella groups, can significantly increase the travel distance of the raw material as it enters the corresponding tank, allowing the raw material to flow a longer distance in a thin layer, which is more conducive to removing the gas inside the raw material.

[0015] The radial dimensions of the debubbling umbrella assembly can be adapted to specific needs; for example, the outer diameter of the lower guide plate can be made slightly smaller than the corresponding inner diameter of the tank.

[0016] Furthermore, a stirring device is provided in the first storage tank, the first working tank, the second storage tank, and the second working tank. The stirring device includes a stirring shaft, and the defoaming umbrella assembly is sleeved on the stirring shaft.

[0017] After passing through the degassing umbrella group, the raw material enters the bottom area of ​​the corresponding tank and is stirred by the stirring device. Under high-speed stirring, the air bubbles in the raw material can be quickly removed, which has a significant enhancing effect on the negative pressure degassing process of this application.

[0018] Furthermore, the A material barrel and the B material barrel are placed on the material platform, and the material platform is equipped with two lifting mechanisms; the two lifting mechanisms are respectively used to drive the pumping device of the A material barrel and the pumping device of the B material barrel to lift.

[0019] The two raw material barrels are used to supply materials to the first and second storage tanks, respectively. Under continuous operation, when the material in the A and B barrels is insufficient, they need to be replaced promptly. Since there are corresponding pumping devices and / or mixing equipment above the two storage tanks, replacing a tank requires disassembling the corresponding pumping devices, which is cumbersome, complex, and inefficient. To overcome this problem, this solution installs two lifting mechanisms on the raw material platform. When a raw material barrel needs to be replaced, the corresponding lifting device raises the pumping device above it, allowing for direct removal and installation of the new barrel. Afterward, the lifting device lowers the pumping device back to its original position. This solution significantly reduces the difficulty of replacing raw material barrels, improves replacement efficiency, and is beneficial for continuous production operations.

[0020] Furthermore, it also includes a color mixing station; the color mixing station includes a color paste tank and a pumping mechanism; the color paste tank is equipped with a defoaming mechanism; The workstation includes a switching valve group connected to the mixing head, which is used to switch between the pumping mechanism corresponding to the first working tank and the pumping mechanism corresponding to the pigment tank.

[0021] Furthermore, some products require PUR materials to be colorless and highly transparent; while others have color matching requirements for PUR materials, and these requirements vary from product to product. Therefore, it is necessary to add corresponding color pastes / pigments to the raw materials according to specific operating conditions, which can easily lead to contamination of the entire equipment by the color pastes / pigments, making cleaning difficult. To overcome this problem, this solution also includes a color mixing station, which includes a color paste tank and a pumping mechanism. The color paste tank also contains a degassing mechanism. The pumping mechanism in this solution is the same as the pumping mechanism in the aforementioned workstation, and the degassing mechanism is the same as the degassing mechanism in the aforementioned storage tank or working tank; therefore, it will not be described in detail here.

[0022] When a product requires a specific color, the color paste tank in this solution is used instead of the first working tank. Material A and the required color paste / pigment are added to the color paste tank, and the switching is performed by switching valve group so that material A is supplied through the color paste tank, while material B is still supplied through the material B raw material tank, the second storage tank and the second working tank.

[0023] When different colors of products need to be produced, this solution only requires changing the color paste tank, which reduces the area of ​​color paste / pigment contamination. After the production of the current color product is completed, only the pipelines related to the color mixing station need to be cleaned, which significantly reduces the cleaning difficulty.

[0024] Furthermore, the mixing head includes a first feed channel, a second feed channel, a first circuit channel, a second circuit channel, and a mixing chamber; it also includes a nozzle for insertion into the mold, the mixing chamber and the nozzle being connected via a discharge channel; and it also includes a first piston, a second piston, and a third piston. The first piston moves within the discharge channel; The second piston moves within the mixing chamber; It also includes an air extraction chamber connected to the discharge channel and / or mixing chamber, and an air extraction channel connected to the air extraction chamber. The third piston moves within the air extraction chamber and is used to open and close the air extraction channel.

[0025] To address the high scrap rate and low yield of products in existing in-mold spray-free processes, the applicant, through extensive research, discovered that the core reason lies in the excessively high gas content in the raw materials and inside the mold. Because polyurethane reactive injection molding is highly sensitive to gas, residual air in the raw materials and mold can lead to significant surface and internal defects after product molding, severely impacting product quality. To overcome this technical problem, this application creatively improves and optimizes the traditional mixing head structure in the polyurethane molding process. The first feed channel, second feed channel, first loop channel, second loop channel, and mixing chamber are all existing technologies for high-pressure mixing heads used in polyurethane reactive injection molding, and will not be elaborated upon here. The nozzle on the mixing head of this solution matches the mold to be processed and is inserted into the mold to achieve in-mold casting. Unlike existing mixing heads with only two pistons, the mixing head of this solution includes three pistons; the first piston moves within the discharge channel to open and close the discharge channel and clean it after operation; the second piston moves within the mixing chamber to open and close the mixing chamber and clean it after operation. The mixing head of this design includes a vacuum chamber and a vacuum channel. The vacuum channel is used to connect to an external vacuum generator. A third piston moves within the vacuum chamber to open and close the vacuum channel.

[0026] Before in-mold pouring, the mixing head first moves the third piston to open the evacuation chamber, connecting the evacuation chamber, evacuation channel, and discharge channel. The vacuum generator then evacuates the air until the internal pressure of the mold reaches the set vacuum level. This allows the mold to reach the required vacuum or negative pressure state before operation, significantly reducing the amount of residual air inside the mold, thereby improving product quality and reducing the scrap rate.

[0027] It should be noted that the traditional approach to in-mold vacuum injection molding technology involves installing vacuum equipment connected to the cavity on the mold, requiring modifications to the mold structure and demanding high sealing standards. Furthermore, as verified by the applicant's experiments, due to the unique properties of polyurethane reactive injection molding materials, adding vacuum equipment to the mold easily leads to material blockage of the corresponding vacuum valves and other components, causing the equipment to fail after only one or a few uses, making it unsuitable for industrial-scale, mass production. Therefore, this solution creatively improves and optimizes the mixing head structure, achieving vacuuming of the mold interior through the mixing head without affecting its inherent function. Compared to the traditional approach to vacuum injection molding, this solution requires no modifications to the mold structure, has no additional sealing requirements, and enables continuous, uninterrupted mass production, truly realizing the industrial-scale, mass production of PUR in-mold coating-free technology.

[0028] Furthermore, the suction chamber and the mixing chamber are distributed on opposite sides of the discharge channel, and the axes of the suction chamber and the mixing chamber are collinear and perpendicular to the axis of the discharge channel; the nozzle end face is provided with a pressure monitoring device for monitoring the air pressure inside the mold.

[0029] This solution avoids interference between vacuuming operations and normal circulating or mixing pouring operations. Furthermore, it allows direct monitoring of the mold's internal pressure via the mixing head, eliminating the need for additional pressure sensors or other equipment on the mold. This eliminates the need for mold modifications and avoids the risks of clogging and damage associated with adding equipment to the mold, further reducing production costs. The pressure monitoring device can monitor the vacuum state inside the mold in real time before pouring and also monitor dynamic pressure changes during pouring, ensuring the accuracy and reliability of the monitoring data. This helps maintain a high product yield and significantly reduces operating and equipment maintenance costs.

[0030] Furthermore, the inner wall of the mixing chamber is provided with two relatively distributed discharge ports, which are respectively used to communicate with the first feed channel and the second feed channel; the discharge direction of the two discharge ports is inclined away from the direction of the discharge channel; the end face of the second piston is arc-shaped, and the concave surface of the arc faces the direction of the discharge channel; the two discharge ports are respectively located at the two ends of the arc.

[0031] In this design, during the mixing process, the second piston is positioned on the side of the two discharge ports furthest from the discharge channel. Materials A and B are ejected obliquely from the two discharge ports towards the direction of the second piston. The two high-pressure materials first collide violently within the mixing chamber, undergoing the first mixing. Then, the mixed materials impact the end face of the second piston, undergoing a second mixing. Furthermore, the two materials are ejected from both ends of the arc towards the center, colliding and mixing before impacting the central region of the concave surface. They then move rapidly to both sides of the arc and turn towards the discharge channel. During this process, the materials form vortices within the mixing chamber, undergoing a third mixing. This design achieves three-stage mixing of the materials through a simple structure, significantly enhancing the mixing effect and ensuring the quality of reaction injection molding, thus improving product yield.

[0032] Furthermore, both the first and second feed channels are equipped with filter components and temperature and pressure monitoring components, with the temperature and pressure monitoring components located downstream of the filter components. The filter assembly includes a connector connected to a first feed channel or a second feed channel, a cover detachably connected to the connector, and a hollow filter element located inside the cover, wherein there is an annular space between the hollow filter element and the cover; the connector includes an inlet channel and an outlet channel, wherein the inlet channel communicates with the annular space, and the outlet channel communicates with the hollow region inside the hollow filter element.

[0033] In existing polyurethane production processes, filtration devices are typically installed on pipelines between the material tank and the mixing head. These pipelines are generally 6-10 meters long and include some flexible tubing. Microcrystalline particles may adhere to the inner walls of these pipelines, severely interfering with product quality. In particular, the in-mold coating-free process for PUR materials involves low-flow, high-pressure mixing and casting, requiring relatively low flow rates. Tiny particles remaining in the raw materials can easily cause pressure fluctuations and blockage of the mixing needle valve, leading to a high equipment failure rate, reduced stability, and severely impacting the continuity of production. Therefore, as verified by the applicant, even with the inclusion of a two-stage filtration system consisting of a first and a second filter in the aforementioned pumping mechanism, it is difficult to guarantee the stability of the system pressure and the cleanliness of the final mixed raw materials.

[0034] To overcome the above problems, this solution is equipped with filter components in both the first and second feed channels inside the mixing head, so that the two raw materials are filtered again before mixing, thereby significantly improving the filtration accuracy of the raw materials, which is particularly suitable for the use of PUR in-mold spray-free process.

[0035] Furthermore, due to the extremely high gas sensitivity of the in-mold coating process for PUR materials, residual gases in the raw materials can cause obvious defects on the product surface, thus seriously affecting product quality. The filter component in this solution, due to its extremely high filtration precision, not only filters the material but also further disperses and refines residual bubbles in the raw materials before mixing. Because the filter component is located inside the mixing head and very close to the mixing chamber, the dispersed and refined microbubbles do not have sufficient travel time to recombine into larger bubbles. Therefore, this solution, through the installation of the filter component, can further reduce the interference of bubbles in the raw materials on product quality and further reduce the scrap rate.

[0036] Due to the small size of the high-pressure mixing head, the space available for installing the filter assembly is limited. Conventional high-pressure filters are too large to fit this application. To overcome this problem, a filter assembly specifically designed for this application has been developed. This filter assembly is connected to the first or second feed channel via a connector, and is connected to the pipelines at both ends via an inlet flow channel and an outlet flow channel. Fluid enters the connector from the inlet flow channel, then enters the annulus between the cover and the hollow filter element. Under pressure, it permeates from the outside to the inside of the hollow filter element until it passes through the hollow region inside the filter element, and then exits from the outlet flow channel.

[0037] As can be seen, this solution innovatively employs an outside-to-inside flow filtration component in the mixing head, allowing the fluid in the first or second feed channel to be filtered separately. This avoids affecting the overall length of the first or second feed channel, resulting in a compact structure and small footprint. Furthermore, the detachable cover facilitates the replacement or cleaning of the internal hollow filter element. Of course, a good seal must be maintained between the cover and the connector.

[0038] Furthermore, the temperature and pressure monitoring component in this solution is used to monitor the temperature and pressure of the two raw material components in real time before mixing. This overcomes the problem in existing technologies where temperature and pressure monitoring can only be performed upstream of the mixing head, resulting in unknown temperature and pressure during final mixing and difficulty in ensuring that the raw materials are mixed under optimal performance conditions. This solution is more suitable for in-mold spray-free coating processes of PUR materials, which have high requirements for the temperature and pressure of the raw materials. The temperature and pressure monitoring component can be implemented using any existing method for monitoring temperature and pressure, and no specific limitations are made here.

[0039] Furthermore, the mixing chamber and the discharge channel are both located inside the shell, and the shell also includes a temperature monitoring device for monitoring the temperature of the shell; it also includes a heating device for heating the shell.

[0040] PUR reactive injection molding is extremely sensitive to raw material temperature. Although insulation layers can be installed on relevant pipelines after the raw material is heated to a set temperature upstream, the temperature inside the mold may not meet the set requirements, thus affecting product quality. The reason for this is that the metal mixing head has excellent thermal conductivity. When the ambient temperature is low, the raw material loses some heat during flow and mixing within the mixing head, causing a drop in temperature, either overall or locally. This results in uneven temperature distribution of the raw material entering the mold, affecting product quality. To overcome this problem, this solution involves temperature monitoring and heating of the mixing head shell. At least the mixing chamber and discharge channel are located inside the shell. Therefore, by maintaining the stability of the shell temperature, heat exchange between the internal raw material and the external environment is reduced, ensuring that the raw material enters the mold at a stable and uniform temperature, thereby improving product quality and increasing yield.

[0041] Compared with the prior art, the present invention has at least the following advantages and beneficial effects: 1. The present invention provides an in-mold coating-free PUR equipment, which can effectively overcome the surface quality problems caused by tiny impurities and bubbles on the product surface in the prior art, and achieve higher appearance quality and yield.

[0042] 2. The present invention provides an in-mold spray-free PUR coating equipment. The degassing mechanism, through the cooperation of a negative pressure extraction device and several degassing umbrella groups, can significantly increase the stroke of the raw material in the corresponding tank. Since the raw material flows in a thin layer, the vacuum system can quickly extract the gas inside the raw material.

[0043] 3. The present invention provides an in-mold coating-free PUR equipment, which, through the design of the raw material platform and its corresponding lifting mechanism, realizes the functions of automatic feeding and continuous production without stopping the machine.

[0044] 4. The present invention provides an in-mold paint-free PUR equipment, which protects the main transparent raw material from cross-contamination by color raw materials by setting up an auxiliary color matching station; by increasing the number of color matching stations, production operations of multiple colors can be realized.

[0045] 5. This invention provides an in-mold coating-free PUR equipment that uses a mixing head to create a vacuum inside the mold and a pressure monitoring device to display the vacuum level in real time. When the vacuum level reaches the injection process requirements, vacuuming stops and injection begins. The dynamic changes in the mold pressure during injection are displayed, and injection ends when the required mold pressure is reached. This ensures the controllability of the injection process and avoids the drawbacks of traditional processes where vacuum valves are installed on the mold for vacuuming, which can easily become clogged. This ensures the continuity of production and the controllability of product quality.

[0046] 6. This invention provides an in-mold coating-free PUR equipment where the two-component raw materials undergo three high-pressure mixing processes within the mixing chamber, enhancing the mixing effect and further improving product yield. Furthermore, before mixing, the raw materials are filtered through a filter assembly within the mixing head, significantly improving filtration accuracy, making it particularly suitable for in-mold coating-free PUR processes. It also reduces the interference of air bubbles and microparticles in the raw materials on product quality, further increasing product yield. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a top view of a specific embodiment of the present invention; Figure 2 This is a side view of the workstation in a specific embodiment of the present invention; Figure 3 This is a cross-sectional view of the degassing mechanism in a specific embodiment of the present invention; Figure 4 This is a partial structural diagram of the raw material platform in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the mixing head in a specific embodiment of the present invention; Figure 6 This is a front view of the mixing head in a specific embodiment of the present invention; Figure 7 For Figure 6 A partial sectional view of the AA direction line; Figure 8 for Figure 7 A magnified view of a section at point C; Figure 9 A side view of the second piston in a specific embodiment of the present invention; Figure 10 For Figure 6 A cross-sectional view of the BB direction line.

[0048] The attached diagram shows the markings and corresponding component names: 1-Mixing head, 2-A material raw material tank, 3-B material raw material tank, 4-Working station, 5-First storage tank, 6-First working tank, 7-Second storage tank, 8-Second working tank, 9-Booster pump, 10-First filter, 11-Metering pump, 12-Second filter, 13-Flow meter, 14-Upper guide plate, 15-Lower guide plate, 16-Agitator, 17-Agitator shaft, 18-Raw material platform, 19-Lifting mechanism, 20-Color paste tank, 21-Negative pressure extraction device, 22-Switching valve group; 101-First feed channel, 102-Second feed channel, 103-First loop channel, 104-Second loop channel, 105-Mixing chamber, 106-Nozzle, 107-Discharge channel, 108-First piston, 109-Second piston, 110-Third piston, 111-Air extraction chamber, 112-Air extraction channel, 113-Pressure monitoring device, 114-Sealing ring, 115-Discharge port, 116-Filter assembly, 1161-Connector, 1162-Cover, 1163-Hollow filter element, 1164-Annular space, 1165-Inlet channel, 1166-Outlet channel, 117-Temperature and pressure monitoring assembly, 118-Housing shell, 119-Temperature monitoring device, 120-Heating device, 121-First piston cylinder, 122-Second piston cylinder, 123-Third piston cylinder. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explaining the invention only and are not intended to limit the invention. In the description of this application, it should be understood that terms such as "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "high," "low," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application.

[0050] Example 1

[0051] like Figures 1 to 3 The PUR in-mold coating-free equipment shown includes an A material tank 2, a B material tank 3, a workstation 4 for pumping raw materials from the A material tank 2 and the B material tank 3, and a mixing head 1 connected to the workstation 4. The A material tank 2 and the workstation 4 are connected in sequence to a first storage tank 5 and a first working tank 6. The B material tank 3 and the workstation 4 are connected in sequence to a second storage tank 7 and a second working tank 8. Degassing mechanisms are provided in the first storage tank 5, the first working tank 6, the second storage tank 7, and the second working tank 8. The workstation 4 includes two sets of pumping mechanisms, which are used for pumping material A from the first working tank 6 to the mixing head 1 and for pumping material B from the second working tank 8 to the mixing head 1, respectively. The pumping mechanism includes a booster pump 9, a first filter 10, a metering pump 11, a second filter 12, and a flow meter 13 connected in sequence. Preferably, the filtration level of the second filter 12 is higher than that of the first filter 10; that is, the pore size of the filter element of the second filter 12 is smaller than that of the filter element of the first filter 10.

[0052] In this embodiment, the defoaming mechanism includes a negative pressure extraction device 21 and several defoaming umbrella groups arranged vertically. It should be noted that... Figure 3 The structure of the degassing mechanism is shown using the second storage tank 7 as an example. Figure 3 The CCP displayed two debubbling umbrella assemblies, and below the lowest debubbling umbrella assembly was a bottom guide plate with an outer diameter slightly smaller than the inner diameter of the second storage tank 7.

[0053] The debubbling umbrella assembly includes an upper guide plate 14 and a lower guide plate 15 that are coaxially distributed vertically. The upper guide plate 14 gradually slopes downward from the inside to the outside in the radial direction, and the lower guide plate 15 gradually slopes downward from the outside to the inside in the radial direction. The bottom outer diameter of the upper guide plate 14 is smaller than the top outer diameter of the corresponding lower guide plate 15. A flow channel is provided at the lower position of the lower guide plate 15.

[0054] The upper guide plate 14 and the lower guide plate 15 can be conical or arc-shaped. For any one of the first storage tank 5, the first working tank 6, the second storage tank 7 and the second working tank 8, its fluid inlet end is located above the uppermost debubbling umbrella group.

[0055] Furthermore, each of the first storage tank 5, the first working tank 6, the second storage tank 7, and the second working tank 8 is equipped with a stirring device 16. The stirring device 16 includes a stirring shaft 17, and the debubbling umbrella assembly is sleeved on the stirring shaft 17. Specifically, both the upper guide plate 14 and the lower guide plate 15 can be fixedly or rotatably connected to the stirring shaft 17. The flow channel is the gap between the lower guide plate 15 and the stirring shaft 17.

[0056] In addition, in this embodiment: the raw materials are pumped from material A barrel 2 to the first storage tank 5 and from material B barrel 3 to the second storage tank 7 by a pressure pump; the raw materials are transported from the first storage tank 5 to the first working tank 6 and from the second storage tank 7 to the second working tank 8 by differential pressure.

[0057] In a more preferred embodiment, both the first working tank 6 and the second working tank 8 are equipped with a temperature control mechanism for regulating the temperature inside the tank.

[0058] Example 2

[0059] A PUR in-mold coating-free equipment, based on Example 1, such as... Figure 1As shown, it also includes a color mixing station; the color mixing station includes a color paste tank 20 and a pumping mechanism; a defoaming mechanism is provided inside the color paste tank 20; the workstation 4 includes a switching valve group 22 connected to the mixing head 1, the switching valve group 22 being used to switch between the pumping mechanism corresponding to the first work tank 6 and the pumping mechanism corresponding to the color paste tank 20.

[0060] When the first working tank 6 is needed to supply material A, the pumping mechanism of the first working tank 6 is connected to the mixing head 1 by switching valve group 22; when the color paste tank 20 is needed to supply material A, the pumping mechanism of the color mixing station is connected to the mixing head 1 by switching valve group 22.

[0061] In this embodiment, as Figure 1 and Figure 4 As shown, the A material raw material barrel 2 and the B material raw material barrel 3 are placed on the raw material platform 18, and the raw material platform 18 is equipped with two lifting mechanisms 19; the two lifting mechanisms 19 are respectively used to drive the pumping device of the A material raw material barrel 2 and the pumping device of the B material raw material barrel 3 to lift.

[0062] In a more preferred embodiment, a top cover matching the raw material tank 2 for material A is also included. The top cover not only has a pumping device for material A, but also a stirring device, which is mainly used to reduce viscosity.

[0063] Example 3

[0064] A PUR in-mold coating-free device, based on embodiment 1 or 2, this embodiment provides a hybrid head 1 structure specifically for this application, such as... Figures 5 to 9 It includes a first feeding channel 101, a second feeding channel 102, a first circuit channel 103, a second circuit channel 104, and a mixing chamber 105; it also includes a nozzle 106 for insertion into the mold, the mixing chamber 105 and the nozzle 106 being connected through a discharge channel 107; it also includes a first piston 108, a second piston 109, and a third piston 110; The first piston 108 moves within the discharge channel 107; The second piston 109 moves within the mixing chamber 105; It also includes an air extraction chamber 111 connected to the discharge channel 107 and / or the mixing chamber 105, and an air extraction channel 112 connected to the air extraction chamber 111. The third piston 110 moves within the air extraction chamber 111 and is used to open and close the air extraction channel 112.

[0065] In this embodiment, the suction chamber 111 and the mixing chamber 105 are distributed on opposite sides of the discharge channel 107, and the axes of the suction chamber 111 and the mixing chamber 105 are collinear and perpendicular to the axis of the discharge channel 107.

[0066] In this embodiment, a pressure monitoring device 113 for monitoring the internal air pressure of the mold is also provided on the end face of the nozzle 106, and an installation groove is provided on the outer wall of the nozzle 106, and a sealing ring 114 is provided in the installation groove.

[0067] The inner wall of the mixing chamber 105 is provided with two oppositely distributed discharge ports 115, which are respectively used to communicate with the first feed channel 101 and the second feed channel 102; the discharge direction of the two discharge ports 115 is inclined away from the discharge channel 107.

[0068] like Figure 9 As shown, the end face of the second piston 109 is arc-shaped, with the concave surface of the arc facing the direction of the discharge channel 107; the two discharge ports 115 are located at the two ends of the arc, i.e. Figure 9 The left and right sides of the middle.

[0069] In this embodiment, the first piston 108, the second piston 109 and the third piston 110 each have a corresponding piston cylinder, namely the first piston cylinder 121, the second piston cylinder 122 and the third piston cylinder 123; preferably, all of them are hydraulic cylinders.

[0070] Those skilled in the art should know that the second piston 109 has two flow channels. When it is necessary to mix raw materials, the second piston 109 retracts, and materials A and B enter the two discharge ports 115 from the two flow channels respectively. When self-circulation is required, the second piston 109 extends, and one flow channel on the second piston 109 connects the first feed channel 101 and the first loop channel 103, and the other flow channel connects the second feed channel 102 and the second loop channel 104.

[0071] Example 4

[0072] Based on Example 1, such as Figures 5 to 10 As shown, a filter assembly 116 and a temperature and pressure monitoring assembly 117 are provided on both the first feed channel 101 and the second feed channel 102, and the temperature and pressure monitoring assembly 117 is located downstream of the filter assembly 116.

[0073] The filter assembly 116 includes a connector 1161 connected to a first feed channel 101 or a second feed channel 102, a cover 1162 detachably connected to the connector 1161, and a hollow filter element 1163 located inside the cover 1162, wherein there is an annular space 1164 between the hollow filter element 1163 and the cover 1162; the connector 1161 includes an inlet flow channel 1165 and an outlet flow channel 1166, wherein the inlet flow channel 1165 communicates with the annular space 1164, and the outlet flow channel 1166 communicates with the hollow region inside the hollow filter element 1163.

[0074] The mixing chamber 105 and the discharge channel 107 are both located inside the housing 118, and a temperature monitoring device 119 for monitoring the temperature of the housing 118 is also included. A heating device 120 for heating the housing 118 is also included. In this embodiment, the heating device 120 is an electric heating rod.

[0075] Preferably, there are two heating devices 120, which are symmetrically distributed on both sides of the nozzle 106.

[0076] Preferably, the filtration levels of the first filter 10, the second filter 12, and the hollow filter element 1163 increase sequentially.

[0077] Preferably, the hollow filter element 1163 uses a filter material with a pore size of less than 1 mm to provide micron-level filtration accuracy.

[0078] Preferably, the axes of the inlet channel 1165 and the outlet channel 1166 are parallel to each other and are both perpendicular to the flow direction of the first feed channel 101 or the second feed channel 102 connected to the connector. The hollow filter element 1163 is cylindrical, and its axis is collinear with the axis of the outlet channel 1166; it has the advantages of compact structure, small space occupation, and easy replacement.

[0079] Example 5

[0080] The production method of the PUR in-mold paint-free equipment based on any of the above embodiments includes the following steps: Step 1: Prepare the mold for the operation; Prepare raw material tank 2 (material A) and raw material tank 3 (material B), and connect all pipeline valves; transfer material A from raw material tank 2 to the first storage tank 5, and at the same time, allow some material A to enter the first working tank 6 for later use; transfer material B from raw material tank 3 to the second storage tank 7, and at the same time, allow some material B to enter the second working tank 8 for later use; simultaneously, start each degassing mechanism to perform degassing.

[0081] Step 2: Connect the mixing head 1 to the mold; preferably, insert the nozzle 106 of the mixing head 1 into the mold to seal the mold and the contact area between the mold and the nozzle 106.

[0082] Step 3: Allow material A to circulate between the first working tank 6 and the mixing head 1, and allow material B to circulate between the second working tank 8 and the mixing head 1, until the temperature and pressure reach the set requirements.

[0083] Step 4: Pour the mixture into the mold through the mixing head.

[0084] Preferably, step four specifically includes: S401, retract the first piston 108, and connect the suction chamber 111 with the suction channel 112; extend the second piston 109 and close the mixing chamber 105; retract the third piston 110, and connect the suction chamber 111 with the suction channel 112.

[0085] S402. Vacuum is drawn from the evacuation channel 112 using a vacuum generator until the internal pressure of the mold reaches the set vacuum level, then the vacuum generator is turned off. During this period, material A is self-circulated through the first feed channel 101 and the first circuit channel 103, and material B is self-circulated through the second feed channel 102 and the second circuit channel 104. The vacuum generator can be a vacuum pump, a negative pressure pump, etc.

[0086] S403, extend the third piston 110 to close the suction chamber 111; retract the second piston 109 to open the mixing chamber 105.

[0087] S404. Material A and material B enter the mixing chamber 105 from the first feeding channel 101 and the second feeding channel 102 respectively. The mixed materials pass through the mixing chamber 105, the discharge channel 107 and the nozzle 106 in sequence and are injected into the mold.

[0088] More preferably, after material A and material B enter the mixing chamber 105 from the first feeding channel 101 and the second feeding channel 102 respectively, material A and material B are ejected obliquely from the two discharge ports 115 toward the direction of the second piston 109. The two high-pressure raw materials first collide violently in the mixing chamber 105 for the first mixing. The mixed raw materials then impact the end face of the second piston 109 for the second mixing. After that, the mixed material moves rapidly along the arc surface of the end face of the second piston 109 and turns toward the discharge channel, forming a vortex in the mixing chamber 105, and is mixed for the third time through the vortex.

[0089] More preferably, step S405 is also included: after the injection is completed, the second piston 109 is extended to close the mixing chamber 105, and the mixing chamber 105 is self-cleaned by the second piston 109. At this time, the two raw materials return to the self-circulation state; the first piston 108 is extended to self-clean the discharge channel 107.

[0090] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0091] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Additionally, the term "connection" as used herein, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

Claims

1. A PUR in-mold coating-free equipment, comprising an A material tank (2), a B material tank (3), a workstation (4) for pumping raw materials from the A material tank (2) and the B material tank (3), and a mixing head (1) connected to the workstation (4), characterized in that, The A material raw material barrel (2) is connected to the work station (4) in sequence by a first storage tank (5) and a first working tank (6), and the B material raw material barrel (3) is connected to the work station (4) in sequence by a second storage tank (7) and a second working tank (8). A degassing mechanism is provided in the first storage tank (5), the first working tank (6), the second storage tank (7), and the second working tank (8); The workstation (4) includes two sets of pumping mechanisms, which are used for pumping material A from the first working tank (6) to the mixing head (1) and material B from the second working tank (8) to the mixing head (1), respectively. The pumping mechanism includes a booster pump (9), a first filter (10), a metering pump (11), a second filter (12), and a flow meter (13) connected in sequence. The mixing head (1) includes a first feed channel (101), a second feed channel (102), a first circuit channel (103), a second circuit channel (104), and a mixing chamber (105); it also includes a nozzle (106) for insertion into the mold, and the mixing chamber (105) and the nozzle (106) are connected through a discharge channel (107); it also includes a first piston (108), a second piston (109), and a third piston (110); The first piston (108) moves within the discharge channel (107); The second piston (109) moves within the mixing chamber (105); It also includes an air extraction chamber (111) communicating with the discharge channel (107) and / or the mixing chamber (105) and an air extraction channel (112) communicating with the air extraction chamber (111), wherein the third piston (110) moves within the air extraction chamber (111) and the third piston (110) is used to open and close the air extraction channel (112). A filter assembly (116) and a temperature and pressure monitoring assembly (117) are provided on both the first feed channel (101) and the second feed channel (102), and the temperature and pressure monitoring assembly (117) is located downstream of the filter assembly (116); The mixing chamber (105) has two oppositely distributed discharge ports (115) on its inner wall. The two discharge ports (115) are respectively used to communicate with the first feed channel (101) and the second feed channel (102). The discharge direction of the two discharge ports (115) is inclined away from the discharge channel (107). The end face of the second piston (109) is arc-shaped, and the concave surface of the arc faces the discharge channel (107). The two discharge ports (115) are located at the two ends of the arc. The filter assembly (116) includes a connector (1161) connected to a first feed channel (101) or a second feed channel (102), a cover (1162) detachably connected to the connector (1161), and a hollow filter element (1163) located inside the cover (1162), wherein there is an annular space (1164) between the hollow filter element (1163) and the cover (1162); the connector (1161) includes an inlet channel (1165) and an outlet channel (1166), wherein the inlet channel (1165) communicates with the annular space (1164), and the outlet channel (1166) communicates with the hollow region inside the hollow filter element (1163); The filtration levels of the first filter (10), the second filter (12), and the hollow filter element (1163) increase sequentially; the hollow filter element (1163) uses a filter material with a pore size of less than 1 mm.

2. The PUR in-mold coating-free equipment according to claim 1, characterized in that, The defoaming mechanism includes a negative pressure extraction device (21) and several defoaming umbrella groups arranged vertically. The debubbling umbrella assembly includes an upper guide plate (14) and a lower guide plate (15) that are coaxial and distributed vertically. The upper guide plate (14) is gradually inclined downward from the inside to the outside in the radial direction, and the lower guide plate (15) is gradually inclined downward from the outside to the inside in the radial direction. The bottom outer diameter of the upper guide plate (14) is smaller than the top outer diameter of the corresponding lower guide plate (15). The lower guide plate (15) is provided with a flow channel at its lower position.

3. The PUR in-mold coating-free equipment according to claim 2, characterized in that, A stirring device (16) is provided in the first storage tank (5), the first working tank (6), the second storage tank (7), and the second working tank (8). The stirring device (16) includes a stirring shaft (17), and the debubbling umbrella group is sleeved on the stirring shaft (17).

4. The PUR in-mold coating-free equipment according to claim 1, characterized in that, The A material barrel (2) and the B material barrel (3) are placed on the raw material platform (18), and two lifting mechanisms (19) are provided on the raw material platform (18); the two lifting mechanisms (19) are used to drive the pumping device of the A material barrel (2) and the pumping device of the B material barrel (3) to lift.

5. The PUR in-mold coating-free equipment according to claim 1, characterized in that, It also includes a color mixing station; the color mixing station includes a color paste tank (20) and a pumping mechanism; the color paste tank (20) is equipped with a defoaming mechanism; The workstation (4) includes a switching valve group (22) connected to the mixing head (1), which is used to switch between the pumping mechanism corresponding to the first working tank (6) and the pumping mechanism corresponding to the pigment tank (20).

6. The PUR in-mold coating-free equipment according to claim 1, characterized in that, The air extraction chamber (111) and the mixing chamber (105) are distributed on opposite sides of the discharge channel (107), and the axes of the air extraction chamber (111) and the mixing chamber (105) are collinear and perpendicular to the axis of the discharge channel (107); the nozzle (106) end face is provided with a pressure monitoring device (113) for monitoring the air pressure inside the mold.

7. The PUR in-mold coating-free equipment according to claim 1, characterized in that, The mixing chamber (105) and the discharge channel (107) are both located inside the shell (118), and the shell (118) is also included with a temperature monitoring device (119) for monitoring the temperature of the shell (118); the shell (118) is also included with a heating device (120) for heating the shell (118).

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