Manufacturing method of vacuum pouring polyurethane product

Abstract

The invention discloses a manufacturing method of a vacuum pouring polyurethane product. The manufacturing method comprises the following steps: S1, heating a mold; s2, cleaning the mold, and closing the mold; s3, the glue injection gun head is moved to the position above the mold, the material A and the material B are added into the glue injection gun head to be stirred, the material A and the material B are mixed, and emptying and waste discharging are conducted on the glue injection gun head; s4, the mixture is poured into a mold cavity of a mold through a glue injection gun head, and the mold cavity of the mold is vacuumized while the mixture is poured; s5, after the mixture is poured, vacuumizing is stopped, and the mixture is cured; and S6, after the mixture is cured, opening the mold, taking out the workpiece, and trimming to obtain a finished product. And S7, when the glue injection gun head needs to wait for not less than 1 minute to pour the mixture again subsequently, the interior of the glue injection gun head is cleaned through a cleaning agent, and dirt is discharged after cleaning. According to the invention, the mixture can be poured and vacuumized at the same time, so that the mixture can be fully filled in the mold cavity of the mold.

Description

Technical Field

[0001] The invention relates to the technical field of methods for producing polyurethane products, and in particular to a method for producing vacuum cast polyurethane products. Background Art

[0002] Polyurethane products are polymer materials made from polyurethane through chemical reactions. They exhibit excellent properties such as wear resistance, hydrolysis resistance, high temperature resistance, low thermal conductivity, low water absorption, and high closed-cell ratio. Some of these properties have reached or exceeded the technical standards of similar products from abroad. Polyurethane has a wide range of applications, including shoe soles, mobile phone cases, and seals.

[0003] Authorization announcement number CN109810236B discloses a method for making a polyurethane sole and a polyurethane raw material used in the method, wherein the method comprises the following steps: A: cleaning a closable mold and preheating the mold to 50-80°C; B: placing the sole accessory to be coated in the mold cavity, which must have been preheated to 50-80°C in advance, and closing the mold; C: evacuating the mold cavity to -0.1Mpa and maintaining the mold cavity in a set vacuum state; D: pouring a mixture of a degassed CPU-type polyurethane prepolymer and a curing agent into the mold cavity and curing it, while the mold is kept at 50-80°C; E: after curing, opening the mold, removing the formed polyurethane-coated sole accessory, and placing it at room temperature for 6-8 hours until the physical properties meet the requirements, trimming the edges, and obtaining the final polyurethane-coated sole accessory product. The CPU type polyurethane prepolymer and the curing agent are mixed in a mass ratio of 100:(40-120) and are evenly mixed at a temperature of 50-60°C. Under the condition that the mold temperature is maintained at 50-80°C, the mixture of the CPU type polyurethane prepolymer and the curing agent reacts in the mold cavity for 10-30 minutes to be cured and formed. The formed polyurethane sole is placed at room temperature for 6-8 hours until the physical properties meet the requirements, and the final polyurethane sole product is obtained.

[0004] However, for the preparation method of the above-mentioned polyurethane soles, it also has some shortcomings, for example: with reference to a vacuum casting polyurethane sole automatic production equipment disclosed in authorization publication number CN222135720U, when casting the polyurethane soles, generally a glue injection gun head is utilized to inject the mixed mixture into the die cavity of the mold. And in the preparation method of the above-mentioned polyurethane soles, it is necessary to vacuumize the mold cavity before pouring the mixture of CPU type polyurethane prepolymer and curing agent into the mold cavity, that is, it adopts a method of vacuumizing first and then pouring. Under this method, when pouring the mixture, the situation that the mixture cannot fully fill the mold cavity may occur, so that the product may have problems such as material spots, bubbles, shrinkage and material shortage, that is, it will eventually affect the yield rate of the product. In addition, in the above method, the glue gun head is not emptied and discharged before pouring into the mold, so that some air and foreign matter may still exist at the nozzle position at the bottom of the glue gun head, and then these air and foreign matter may be poured into the mold cavity during the pouring process, which may cause the product to have problems such as material spots, bubbles, shrinkage and material shortages, ultimately affecting the product yield. Moreover, in the above method, the glue gun head is not cleaned after pouring. If the time interval for waiting for the next pouring is too long, the residual mixture in the glue gun head may solidify, which will affect the normal use of the glue gun head and the production quality of the product. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for manufacturing a vacuum-cast polyurethane product, which adopts a method of pouring the mixture while evacuating the mixture, thereby ensuring that the mixture can be fully filled in the mold cavity of the mold, making the product less likely to have problems such as material flowers, bubbles, shrinkage and material shortages, thereby ensuring the yield rate of the product; in addition, when pouring the mold cavity of the first mold, it will also perform emptying and waste discharge operations and when the pouring is completed and temporarily no longer needed, the glue injection gun head will be cleaned, thereby also avoiding problems such as material flowers, bubbles, shrinkage and material shortages in the product, thereby ensuring the yield rate of the product.

[0006] In order to achieve the above object, the technical solution of the present invention is: A method for manufacturing a vacuum cast polyurethane product comprises the following steps: S1, heating the mold; S2, opening and cleaning the mold, and then closing the mold; S3, moving the glue injection gun head to the top of the mold, adding material A and material B, which are polyurethane material and curing agent respectively, into the glue injection gun head and stirring them to uniformly mix material A and material B into a mixture, then extruding a certain amount of the mixture from the glue injection gun head to complete the emptying and waste operation of the glue injection gun head; S4, using the glue injection gun head to press the feed port of the mold and pour the mixture into the mold cavity of the mold, and in addition, vacuuming the mold cavity while pouring the mixture, forming an operation of pouring the mixture while vacuuming; S5. After the mixture is poured, the vacuum pumping stops and the mixture is allowed to solidify. S6. After the mixture is solidified, the mold is opened, the workpiece is removed and subsequent trimming is performed to finally obtain a finished polyurethane product; S7. When the glue injection gun head needs to wait for no more than 30 seconds before pouring the mixture again, the inside of the glue injection gun head is not cleaned; when the glue injection gun head needs to wait for no less than 1 minute before pouring the mixture again, the inside of the glue injection gun head is cleaned with a detergent, and the glue injection gun head discharges the dirt after cleaning is completed.

[0007] Furthermore, in step S4, the glue injection gun head sequentially pours the mixture into the plurality of molds within a certain period of time, and the plurality of molds form a group of mold assemblies; and the glue injection gun head only needs to perform an emptying and waste removal operation before pouring into the first mold of the group of mold assemblies; In step S6, after the workpiece is taken out of the mold, the mold needs to be cleaned; In step S7, after the glue injection gun head has poured one of the molds in a group of the mold assemblies, it waits for no more than 30 seconds and then moves to the next mold and pours it; when the glue injection gun head has poured the last mold in the group of the mold assemblies, it is necessary to pause the pouring in order to remove the workpieces in each mold and clean each mold. During the cleaning process, when the glue injection gun head has waited for no less than 1 minute, it is necessary to clean the inside of the glue injection gun head with a detergent; after ensuring that all molds in the group of mold assemblies have been cleaned, each mold is poured again in turn.

[0008] Furthermore, in step S4, before pouring the mixture into each mold, the injection gun head needs to add a certain amount of material A and material B into the injection gun head for stirring, so that the amount of the mixed mixture matches the space of the corresponding mold cavity of the mold.

[0009] Furthermore, in step S1, after heating the mold for 1-2 hours, the mold is heated to 60°C-100°C.

[0010] Furthermore, in step S2, after the mold is opened and cleaned, a textile fabric sprayed with ink is placed in the mold cavity of the mold, and then the mold is closed.

[0011] Furthermore, in step S3, during the emptying and waste discharge operation, the material receiving bucket is moved to the bottom of the glue injection gun head and loaded with the waste discharged by the glue injection gun head. After the emptying and waste discharge operation is completed, the material receiving bucket is removed.

[0012] Furthermore, in step S3, the action of the glue injection gun head extruding the mixture lasts for 4-8 seconds.

[0013] Furthermore, in step S5, the curing time of the mixture is 600 seconds to 1000 seconds.

[0014] Furthermore, in step S7, when the glue injection gun head is cleaned, it is rinsed by using a cleaning mechanism that can spray detergent; when the glue injection gun head discharges the dirt, the dirt is loaded through the material receiving bucket.

[0015] The beneficial effects of the present invention are: (1) The glue injection gun head of the present invention performs a vacuum operation while pouring the mixture into the inner cavity of the mold, that is, a method of pouring the mixture while vacuuming is realized to ensure that the mixture can be fully filled in the mold cavity and the product is not prone to problems such as material spots, bubbles, shrinkage and material shortages, that is, the product yield is guaranteed.

[0016] (2) Because the present invention also empties and discharges waste from the glue injection gun tip before pouring into the mold cavity to ensure that there is no air and foreign matter at the nozzle position of the glue injection gun tip, it can prevent these air and foreign matter from being poured into the mold later and causing problems such as material flowers, bubbles, shrinkage and material shortages in the product.

[0017] (3) When the glue injection gun head is not needed temporarily, for example, when it is necessary to wait for not less than 1 minute, the present invention will automatically use a detergent to clean the glue injection gun head to ensure the cleanliness of the glue injection gun head and avoid the mixture from solidifying after being stored in the glue injection gun head for a long time, thereby affecting the normal use of the glue injection gun head and affecting the production quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a principle framework diagram of the present invention. DETAILED DESCRIPTION

[0019] The invention will be further described below with reference to the accompanying drawings and specific embodiments. The following description is merely illustrative and does not limit the scope of protection of the invention.

[0020] like Figure 1 As shown, a method for manufacturing a vacuum cast polyurethane product comprises the following steps: S1, heating the mold; S2, open and clean the mold, and then close the mold; S3. Move the glue injection gun head to the top of the mold, add material A and material B, which are polyurethane material and curing agent respectively, into the glue injection gun head and stir them to evenly mix material A and material B into a mixture. Then, the glue injection gun head extrude a certain amount of the mixture to complete the emptying and waste operation of the glue injection gun head. It should be noted that in the process of emptying and waste discharge of the glue injection gun head, it is not advisable to extrude too much mixture. The amount should be designed according to actual needs to ensure sufficient use effect. S4. Using the glue injection gun head to press the inlet of the mold and pour the mixture into the mold cavity of the mold. In addition, while pouring the mixture, the mold cavity is also vacuumed, so that the mixture is poured and the vacuum is simultaneously drawn. Specifically, the vacuuming operation can be performed using a vacuum pump. Of course, the position of the vacuuming hole can be set at the upper end of the side wall of the mold cavity to prevent the mixture from being sucked away during the pouring process. S5. After the mixture is poured, the vacuum pumping stops and the mixture is allowed to solidify. S6. After the mixture is solidified, the mold is opened, the workpiece is removed and subsequent trimming is performed to finally obtain a finished polyurethane product; S7. When the glue injection gun head needs to wait for no more than 30 seconds before pouring the mixture again, the inside of the glue injection gun head is not cleaned; when the glue injection gun head needs to wait for no less than 1 minute before pouring the mixture again (for example, when cleaning the mold), the inside of the glue injection gun head is cleaned with a detergent, and the glue injection gun head discharges the dirt after cleaning.

[0021] If there is only one mold, the process of cyclically producing polyurethane products can be achieved by simply repeating steps S2-S7.

[0022] This article takes the production of polyurethane soles as an example, and the equipment used for producing polyurethane products in the above steps can be the equipment disclosed in the patent document "A Vacuum Casting Polyurethane Sole Automated Production Equipment" disclosed with authorization announcement number CN222135720U.

[0023] In summary, the glue gun head of the present invention will simultaneously perform a vacuum operation when pouring the mixture into the mold cavity, that is, a method of pouring the mixture while vacuuming is implemented to ensure that the mixture can be fully filled in the mold cavity, and the product is not prone to problems such as material flowers, bubbles, shrinkage and lack of materials, that is, to ensure the product yield. In addition, because the present invention will also empty and discharge the glue gun head before pouring into the mold cavity to ensure that there is no air and foreign matter at the nozzle position of the glue gun head, it can be avoided that these air and foreign matter will be poured into the mold later and cause the product to have material flowers, bubbles, shrinkage and lack of materials. Moreover, when the glue gun head is temporarily not needed, for example, when it needs to wait for at least 1 minute, the present invention will automatically use a detergent to clean the glue gun head to ensure the cleanliness of the glue gun head and avoid the mixture from being easily solidified after being stored in the glue gun head for a long time, thereby affecting the normal use of the glue gun head and affecting the production quality of the product.

[0024] The following is a more detailed description of each step above, as follows: In step S4, the glue injection gun head pours the mixture into the multiple molds in sequence within a certain period of time. The specific time can be set according to the number of molds. For example, the pouring interval between two molds can be set to within 30 seconds. The multiple molds form a group of mold components. In this embodiment, the number of molds in the group of mold components is five. Moreover, the glue injection gun head only needs to be emptied and discharged before pouring the first mold of the group of mold components. After that, the glue injection gun head no longer needs to be emptied and discharged when pouring the other molds in the group of mold components in sequence, because the air and foreign matter in the glue injection gun head have been discharged after the emptying and discharge. In step S6, the glue is taken out of the mold. After pouring the workpiece, the mold needs to be cleaned; in step S7, after the glue gun head pours one of the molds in a group of mold assemblies, it waits for no more than 30 seconds and then moves to the next mold and pours, that is, in this process, the inside of the glue gun head does not need to be cleaned; when the glue gun head pours the last mold in the group of mold assemblies, it is necessary to pause the pouring in order to take out the workpieces in each mold and clean each mold. During the cleaning process, when the glue gun head waits for no less than 1 minute, the inside of the glue gun head needs to be cleaned with a detergent; after ensuring that each mold in the group of mold assemblies has been cleaned, each mold is poured again in turn. It can be seen that the above steps are for the case where multiple molds are set up. After setting the above steps, the glue injection gun head can be used with multiple molds. Moreover, during use, after the solidified workpiece is taken out, the staff needs to clean it up afterwards to facilitate reuse. In addition, since cleaning multiple molds takes a lot of time, for example, more than 1 minute, at this time, in order to avoid the residual mixture in the glue injection gun head from solidifying and affecting the subsequent use of the glue injection gun head, it is necessary to use a cleaning mechanism to clean out the residue inside the glue injection gun head to ensure that there will be no residual mixture in the glue injection gun head during subsequent use, and also to ensure the production quality of the product, so that the product is not prone to problems such as material flowers, bubbles, shrinkage and material shortages.

[0025] More specifically, in step S4, before pouring the mixture into each mold, the glue injection gun head needs to add a certain amount of material A and material B into the glue injection gun head and stir them so that the amount of the mixed mixture matches the space of the mold cavity of the corresponding mold. It can be seen that in step S4, the amount of the mixture mixed by material A and material B added to the glue injection gun head each time is only enough to pour the mold cavity of one mold. When pouring the next mold, it is necessary to re-inject a certain amount of material A and material B into the glue injection gun head. This design prevents the glue injection gun head from storing too much mixture for a long time, so as to avoid the mixture from easily solidifying after being stored for a long time, which affects the normal use of the glue injection gun head and the production quality of the product.

[0026] In step S1, after heating the mold for 1-2 hours, the mold is heated to 60°C-100°C. The specific temperature can be determined according to the actual needs of the material formula of the mixture, and no specific examples are given here.

[0027] In step S2, before adding material A and material B to the glue injection gun head, material A and material B are placed in barrel A and barrel B with stirring function respectively for degassing operation. Since the degassing operation belongs to the existing technology, it will not be described in detail here.

[0028] In step S2, after opening and cleaning the mold, textile fabric sprayed with ink is placed in the mold cavity of the mold, and then the mold is closed, so that polyurethane soles with textile fabrics can be produced subsequently to meet different market demands.

[0029] In step S3, during the emptying and waste removal process, a material receiving bucket is moved below the glue gun head and loaded with the waste material discharged by the glue gun head. After the emptying and waste removal process is completed, the material receiving bucket is removed. The movement of the material receiving bucket can be achieved by a linear module or a conventional structure, which will not be described further here. This step effectively removes the waste material generated during the emptying and waste removal process, preventing it from spilling onto the machine platform and affecting normal operation.

[0030] In step S3, the glue injection gun head extrude the mixture for 4-8 seconds, thereby ensuring the effect of emptying and discharging waste, that is, the air and foreign matter in the nozzle position of the glue injection gun head can be effectively discharged.

[0031] In step S5 , the curing time of the mixture is 600 seconds to 1000 seconds, so that the mixture has sufficient time to cure. The above time can be determined according to the actual needs of the material formula of the mixture.

[0032] In step S7, when cleaning the glue gun head, it is rinsed by a cleaning mechanism that can spray a cleaning agent; when the glue gun head discharges the waste material, the waste material is loaded into the receiving bucket. Therefore, the above design uses a cleaning agent to clean the glue gun head, thereby ensuring the cleaning effect.

[0033] Furthermore, because the mold is closed, unlike open casting molds, which rely entirely on gravity to level the material, the product shape is not restricted and can be made into various shapes, including three-dimensional shapes. The entire production process does not exceed 100°C, and the product is cured in the closed mold, so no volatile substances are generated.

[0034] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications of the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims of the present invention and equivalent technologies, the present invention is also intended to include these changes and modifications.

Claims

1. A method for producing a vacuum cast polyurethane product, characterized in that: The following steps are involved: S1, heating the mold; S2, opening and cleaning the mold, and then closing the mold; S3, moving the glue injection gun head to the top of the mold, adding material A and material B, which are polyurethane material and curing agent respectively, into the glue injection gun head and stirring them to uniformly mix material A and material B into a mixture, then extruding a certain amount of the mixture from the glue injection gun head to complete the emptying and waste operation of the glue injection gun head; S4, using the glue injection gun head to press the feed port of the mold and pour the mixture into the mold cavity of the mold, and in addition, vacuuming the mold cavity while pouring the mixture, forming an operation of pouring the mixture while vacuuming; S5. After the mixture is poured, the vacuum pumping stops and the mixture is allowed to solidify. S6. After the mixture is solidified, the mold is opened, the workpiece is removed and subsequent trimming is performed to finally obtain a finished polyurethane product; S7. When the glue injection gun head needs to wait for no more than 30 seconds before pouring the mixture again, the inside of the glue injection gun head is not cleaned; when the glue injection gun head needs to wait for no less than 1 minute before pouring the mixture again, the inside of the glue injection gun head is cleaned with a detergent, and the glue injection gun head discharges the dirt after cleaning is completed.

2. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S4, the glue injection gun head sequentially pours the mixture into the plurality of molds over a period of time, and the plurality of molds form a set of mold assemblies; and the glue injection gun head only needs to perform an emptying and waste removal operation before pouring into the first mold of the set of mold assemblies; In step S6, after the workpiece is taken out of the mold, the mold needs to be cleaned; In step S7, after the glue injection gun head has poured one of the molds in a group of the mold assemblies, it waits for no more than 30 seconds and then moves to the next mold and pours it; when the glue injection gun head has poured the last mold in the group of the mold assemblies, it is necessary to pause the pouring in order to remove the workpieces in each mold and clean each mold. During the cleaning process, when the glue injection gun head has waited for no less than 1 minute, it is necessary to clean the inside of the glue injection gun head with a detergent; after ensuring that all molds in the group of mold assemblies have been cleaned, each mold is poured again in turn.

3. The method for producing a vacuum cast polyurethane product according to claim 2, wherein: In step S4, before pouring the mixture into each mold, the injection gun head needs to add a certain amount of material A and material B into the injection gun head and stir them so that the amount of the mixed mixture matches the space of the corresponding mold cavity of the mold.

4. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S1, after heating the mold for 1-2 hours, the mold is heated to 60°C-100°C.

5. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S2, after the mold is opened and cleaned, a textile fabric sprayed with ink is placed in the mold cavity of the mold, and then the mold is closed.

6. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S3, during the emptying and waste discharge operation, the material receiving bucket is moved to the bottom of the glue injection gun head and loaded with the waste discharged by the glue injection gun head. After the emptying and waste discharge operation is completed, the material receiving bucket is removed.

7. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S3, the glue injection gun head extrude the mixture for 4-8 seconds.

8. The method for producing a vacuum cast polyurethane product according to claim 7, wherein: In step S5 , the mixture is cured for 600 seconds to 1000 seconds.

9. The method for producing a vacuum cast polyurethane product according to claim 1, wherein: In step S7, when the glue injection gun head is cleaned, it is rinsed by using a cleaning mechanism that can spray detergent; when the glue injection gun head discharges the dirt, the dirt is loaded into the receiving bucket.

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