A method of compression molding and a molded part

Abstract

The application discloses a molding method and a molded part, and relates to the technical field of molding, and comprises the following steps: heating a mold to a preset temperature and keeping the temperature; placing a fiber reinforced material in a molding cavity of the mold, closing the mold and compacting the fiber reinforced material; injecting fireproof paint into the molding cavity; vacuumizing the molding cavity; keeping the temperature and pressure of the molding cavity constant, and solidifying the fireproof paint and the fiber reinforced material to form a molded part.

Description

Technical Field

[0001] This application relates to the field of compression molding technology, and in particular to a compression molding method and a molded part. Background Technology

[0002] Compression molding, as a forming process for relatively large flat products, is widely used in the processing of automotive interior parts such as spare tire covers, wardrobes, headliners, and foot pedals. It offers advantages such as low processing costs, low-cost molding equipment, simple mold structure, good product repeatability, ease of automation and high production efficiency, and the ability to mold complex products in a single step.

[0003] For heavy-duty car trunk covers, the current main material is PHC (Polyurethane Composites) wet-process paper honeycomb board, which requires subsequent glue spraying and edge wrapping. The process is complex and results in a long operation cycle. Summary of the Invention

[0004] This application aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the purpose of this application is to provide a molding method and a molded part that can mold fiber-reinforced materials and fire-retardant coatings in one step, simplifying the process and thus shortening the construction cycle.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: This application provides a compression molding method, including the following steps: Heat the mold to the preset temperature and keep it warm; The fiber-reinforced material is placed in the molding cavity of the mold, and the mold is closed and the fiber-reinforced material is pressed tightly. Fire-retardant coating is injected into the molding cavity; The molding cavity is evacuated; Maintain a constant temperature and pressure in the molding cavity to allow the fire-retardant coating and the fiber-reinforced material to cure and solidify.

[0006] The molding method provided in this application has at least the following beneficial effects: by placing the fiber-reinforced material in the molding cavity, and then injecting fire-retardant coating into the molding cavity, the fire-retardant coating is evenly coated on the surface of the fiber-reinforced material. Then, by closing the mold and continuously heating the molding cavity, the fire-retardant coating and the fiber-reinforced material are cured and formed. The fiber-reinforced material and the fire-retardant coating can be molded in one step, which is simple and shortens the construction cycle.

[0007] In some embodiments, placing the fiber-reinforced material in the molding cavity of the mold, closing the mold, and pressing the fiber-reinforced material includes: The mold closing pressure is set to 15MPa~20MPa.

[0008] In some embodiments, injecting the fire-retardant coating into the molding cavity includes: The base material and flame retardant are stirred and mixed in a vacuum environment according to a predetermined ratio to obtain the fireproof coating; Maintaining a constant temperature and pressure in the molding cavity, the fire-retardant coating is injected into the molding cavity.

[0009] In some embodiments, the step of mixing the base material and the flame retardant in a vacuum environment at a predetermined ratio to obtain the fire-retardant coating includes: The base material is set as a reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine; The flame retardant is set as any one of ammonium pentaborate hydrate, ethylene oxide, or ammonium polyphosphate. The ratio of the base material to the flame retardant is set to 3.6:1 to 4.4:1.

[0010] In some embodiments, the step of mixing the base material and the flame retardant in a vacuum environment at a predetermined ratio to obtain the fire-retardant coating includes: Set the stirring temperature to 45℃~55℃, the stirring time to 5min, and the vacuum degree to 1MPa~5MPa.

[0011] In some embodiments, evacuating the molding cavity includes: The vacuum level of the molding cavity is set to 1MPa~5MPa.

[0012] In some embodiments, maintaining a constant temperature and pressure in the molding cavity to allow the fire-retardant coating and the fiber-reinforced material to cure and solidify includes: The curing time for the fire-retardant coating and the fiber-reinforced material in the mold is set to 5 min to 10 min.

[0013] In some embodiments, heating the mold to the preset temperature and maintaining that temperature includes: Heat transfer oil is continuously supplied into the mold to heat the mold and the molding cavity; After the temperature of the molding cavity reaches the preset temperature, it is kept warm.

[0014] In some embodiments, the preset temperature is set to 95°C to 105°C.

[0015] This application also provides a molded part, which is manufactured by compression molding. Attached Figure Description

[0016] Figure 1 This is a flowchart of the compression molding method provided in this embodiment; Figure 2 This is a schematic diagram of the mold structure; Figure 3 The product is assembled from two semi-circular molded parts; Figure 4 This is a product assembled from two L-shaped molded parts; Figure 5 It is a roll-formed part.

[0017] 100. Upper template; 110. Injection hole; 120. Overflow hole; 200, lower mold plate; 210, molding cavity; 220, vacuum hole; 300. Molded parts. Detailed Implementation

[0018] The embodiments of this application are described in detail below with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0019] In the description of this application, it should be understood that the terms "center", "middle", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and 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 a limitation of this application.

[0020] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0021] In the description of this application, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0022] In the description of this application, the use of terms such as "one embodiment," "some embodiments," "an example," "some instances," "some embodiments," "illustrative embodiment," "example," "specific example," and "some examples" indicates that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0023] Reference Figures 1 to 5 This embodiment provides a compression molding method, including the following steps: Step S1: Heat the mold to a preset temperature and maintain it at that temperature. In this embodiment, preheating the mold before compression molding reduces waiting time and helps shorten the processing cycle. The mold includes an upper mold plate 100 and a lower mold plate 200, both of which are equipped with heating chambers. By introducing high-temperature heat-conducting oil into the heating chambers, the upper mold plate 100 and the lower mold plate 200 can be heated. It is understood that the heating temperature of the upper mold plate 100 and the lower mold plate 200 depends on the temperature of the heat-conducting oil. By controlling the temperature of the heat-conducting oil, the heating temperature of the mold can be controlled. Once the mold is heated to the preset temperature, the temperature of the mold is maintained at the preset temperature.

[0024] Step S2: Place the fiber-reinforced material into the molding cavity 210 of the mold, close the mold, and press the fiber-reinforced material. In this embodiment, the molding cavity 210 is located on the top surface of the lower mold plate 200. During use, the fiber-reinforced material is laid flat on the inner bottom of the molding cavity 210. The fiber-reinforced material can be a composite reinforcing material such as chopped strand mat, basalt chopped strand mat, or warp and weft woven mat, which has a lower cost and better bonding performance with fire-retardant coatings. It is understood that when the upper mold plate 100 and the lower mold plate 200 are closed, the fiber-reinforced material in the molding cavity 210 can be squeezed, thereby applying a certain closing pressure to the fiber-reinforced material.

[0025] Step S3: Inject the fire-retardant coating into the molding cavity 210. In this embodiment, the upper mold plate 100 is provided with an injection hole 110 and an overflow hole 120. When liquid fire-retardant coating is continuously injected into the molding cavity 210 through the injection hole 110, the liquid fire-retardant coating will uniformly fill the gap between the fiber reinforcement material and the molding cavity 210, thereby ensuring that the fire-retardant coating can uniformly coat the surface of the fiber reinforcement material, ensuring that the processed molded part 300 has a uniform thickness and good consistency. When the fire-retardant coating in the molding cavity 210 overflows, the excess fire-retardant coating will be discharged from the overflow hole 120, thereby ensuring that the fire-retardant coating completely fills the internal gaps of the molding cavity 210, reducing the occurrence of uneven thickness and blistering of the fire-retardant coating. It can be understood that during the process of the mold extruding the fire-retardant coating and the fiber reinforcement material, the air escaping from its interior can also be discharged from the overflow hole 120.

[0026] Step S4: Vacuum the molding cavity 210. In this embodiment, the lower template 200 is provided with a plurality of vacuum holes 220. The vacuum holes 220 are used to connect to an external vacuum pump. The external vacuum pump can evacuate the inside of the molding cavity 210 through the vacuum holes 220 to form a vacuum processing environment, thereby enabling the fire-retardant coating to fill the molding cavity 210 faster and more evenly, which helps to reduce the processing cycle of a single molded part 300.

[0027] Step S5: Maintain a constant temperature and pressure in the molding cavity 210 to allow the fire-retardant coating and fiber-reinforced material to cure and solidify. In this embodiment, the fiber-reinforced material and fire-retardant coating are molded in one step using a mold, which is a simple process and produces a product with a dense internal structure and high strength.

[0028] Understandably, during the mold closing process of the upper mold 100 and the lower mold 200, on the one hand, the fiber-reinforced material in the molding cavity 210 can be compacted, reducing the porosity inside the fiber-reinforced material and making the internal structure of the fiber-reinforced material dense. On the other hand, the fire-retardant coating can be squeezed, making the fire-retardant coating and the fiber-reinforced material in close contact. It can also squeeze out the tiny air bubbles inside the fire-retardant coating, reducing the porosity inside the fire-retardant coating, thereby improving the water resistance and adhesion of the fire-retardant coating formed after the fire-retardant coating is cured.

[0029] In some embodiments, placing the fiber-reinforced material in the molding cavity 210 of the mold, closing the mold and pressing the fiber-reinforced material includes: The mold closing pressure is set to 15MPa~20MPa. In this embodiment, this range is the optimal mold closing pressure range, ensuring the processing quality of the molded parts. Specifically, if the mold closing pressure is less than 15MPa, the fiber reinforcement material inside the mold will not be able to completely fill the molding cavity, resulting in problems such as rough surface and insufficient strength in the product. If the mold closing pressure is greater than 20MPa, the flow resistance of the fiber reinforcement material in the molding cavity will increase, making it easier for air bubbles to form inside the molded parts. It is understood that the mold closing pressure can also be adjusted according to different materials and product shapes. For example, when processing materials with simple shapes and small sizes, the mold closing pressure can be set to 15MPa~17MPa, while when processing materials with complex shapes and large sizes, the mold closing pressure can be set to 18MPa~20MPa.

[0030] In some embodiments, injecting fire-retardant coating into molding cavity 210 includes: The base material and flame retardant are stirred and mixed in a vacuum environment according to a predetermined ratio to obtain a fireproof coating; Maintaining a constant temperature and pressure in the molding cavity 210, the fire-retardant coating is injected into the molding cavity 210. In this embodiment, the base material and flame retardant are stirred and mixed in a vacuum environment, which can reduce the air mixed in the fire-retardant coating, thereby reducing uneven thickness and blistering of the cured fire-retardant coating and improving the molding quality of the fire-retardant coating.

[0031] In some embodiments, the base material and flame retardant are stirred and mixed in a vacuum environment at a predetermined ratio to obtain a fire-retardant coating, comprising: The base material is set as the reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine; The flame retardant is set as any one of ammonium pentaborate hydrate, ethylene dioxygenate, or ammonium polyphosphate. The ratio of base material to flame retardant is set to 3.6:1 to 4.4:1. In this embodiment, the CAS number corresponding to the reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine is 68410-23-1. The above-mentioned ratio range of base material to flame retardant is the optimal mixing ratio range for fire-retardant coatings. For example, when the ratio of base material to flame retardant is set to 4:1, the resulting fire-retardant coating has excellent hot-pressing molding performance and is not prone to cracking during hot-pressing deformation.

[0032] In some embodiments, the base material and flame retardant are stirred and mixed in a vacuum environment at a predetermined ratio to obtain a fire-retardant coating, comprising: The stirring temperature was set to 45℃~55℃, the stirring time to 5 minutes, and the vacuum degree to 1MPa~5MPa. In this embodiment, the above temperature range is the optimal temperature range for stirring the fire-retardant coating. Within this temperature range, the flow properties of the base material and flame retardant can be ensured, and the mixing can be more uniform.

[0033] In some embodiments, evacuating the molding cavity 210 includes: Set the vacuum level of the molding cavity 210 to 1MPa~5MPa.

[0034] In some embodiments, maintaining a constant temperature and pressure in the molding cavity 210 to allow the fire-retardant coating and fiber-reinforced material to cure and solidify includes: The curing time for the fire-retardant coating and fiber-reinforced material in the mold is set to 5 to 10 minutes. This range represents the optimal time for molding the fire-retardant coating and fiber-reinforced material. It is understood that users can adjust the curing time according to the product thickness. For example, if the part to be molded is thin, the curing time can be set to 5 to 7 minutes; if the part to be molded is thick, the curing time can be set to 8 to 10 minutes.

[0035] In some embodiments, heating the mold to a preset temperature and maintaining that temperature includes: High-temperature heat transfer oil is continuously introduced into the mold to heat the mold and the molding cavity 210; After the temperature of the molding cavity 210 reaches the preset temperature, it is kept at that temperature. In this embodiment, the high-temperature heat transfer oil can be provided by an external heat transfer oil storage tank, which is also equipped with components such as heating wires to heat the heat transfer oil to any temperature. When molding is required, the high-temperature heat transfer oil in the external heat transfer oil storage tank can be pumped from the inlet pipe to the heating cavity through the pump body to uniformly heat the upper mold plate 100 and the lower mold plate 200. After the molded part 300 is processed, the heat transfer oil in the heating cavity can be pumped back to the external heat transfer oil storage tank through the outlet pipe to achieve the recycling of the heat transfer oil. It can be understood that the operator can indirectly control the temperature of the molding cavity 210 by adjusting the temperature of the heat transfer oil to adapt to the processing of molded parts 300 of different specifications and models.

[0036] In some embodiments, the preset temperature is set to 95°C to 105°C. This temperature range is the curing temperature of the fire-retardant coating and the fiber-reinforced material. It is understood that the user can adjust the preset temperature according to the product thickness. For example, if the part to be processed is thin, the preset temperature can be set to 95°C to 100°C, and if the part to be processed is thick, the preset temperature can be set to 100°C to 105°C.

[0037] This embodiment also provides a molded part, which is obtained by compression molding.

[0038] Example 1 Taking a molded semi-circular part 300 as an example, its thickness is 3mm, length is 1000mm, inner diameter is 88.9mm, and weight is 1.26kg. Furthermore, by interlocking two semi-circular parts 300, an outer fireproof cover applicable to conventional oil and gas pipelines can be obtained, such as... Figure 3 As shown.

[0039] Step S1: Heat the upper mold plate 100 and lower mold plate 200 of the mold by passing high temperature heat transfer oil through them, and maintain the temperature of the mold and the molding cavity 210 at 100℃. Step S2: Lay the chopped fiberglass mat flat in the molding cavity 210, then close the mold and maintain the closing pressure at 18MPa. Step S3: Mix approximately 1.30 kg of the reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine with any one of ammonium pentaborate hydrate, ethylene oxide, or ammonium polyphosphate in a vacuum environment at a ratio of 4:1. The stirring temperature is 50°C, the stirring time is 5 min, and the vacuum pressure is preferably 3 MPa. Open the overflow hole 120 and inject the fire retardant coating into the molding cavity 210 through the injection hole 110 until some of the fire retardant coating overflows from the overflow hole 120, then stop the injection. Step S4: Close the injection hole 110 and the overflow hole 120. The external vacuum pump evacuates the molding cavity 210 through the vacuum hole 220 to 3MPa and then stops to remove the air in the molding cavity 210. Step S5: While maintaining the temperature of the molding cavity 210 at 100°C and the mold closing pressure at 18MPa, the fire retardant coating and fiber reinforcement material are hot-pressed in the mold for 8 minutes, thereby allowing the fire retardant coating and fiber reinforcement material to solidify and form. Step S6: Turn off the external vacuum pump, open the mold and remove the part to obtain a semi-circular molded part 300.

[0040] Example 2 Taking the L-shaped molded part 300 as an example, its thickness is 3mm, its length is 1000mm, and its inner width is 100mm. It measures 60mm in diameter and weighs 1.44kg. Furthermore, by interlocking two L-shaped molded parts at 300mm intervals, an outer fireproof cover applicable to conventional battery cells and cable trays can be obtained, such as... Figure 4 As shown.

[0041] Step S1: Heat the upper mold plate 100 and lower mold plate 200 of the mold by passing high temperature heat transfer oil through them, and maintain the temperature of the mold and the molding cavity 210 at 100℃. Step S2: Lay the chopped fiberglass mat flat in the molding cavity 210, then close the mold and maintain the closing pressure at 18MPa. Step S3: Mix approximately 1.50 kg of the reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine with any one of ammonium pentaborate hydrate, ethylene oxide, or ammonium polyphosphate in a vacuum environment at a ratio of 4:1. The stirring temperature is 50°C, the stirring time is 5 min, and the vacuum pressure is preferably 3 MPa. Open the overflow hole 120 and inject the fire retardant coating into the molding cavity 210 through the injection hole 110 until some of the fire retardant coating overflows from the overflow hole 120, then stop the injection. Step S4: Close the injection hole 110 and the overflow hole 120. The external vacuum pump evacuates the molding cavity 210 through the vacuum hole 220 to 3MPa and then stops to remove the air in the molding cavity 210. Step S5: While maintaining the temperature of the molding cavity 210 at 100°C and the mold closing pressure at 18MPa, the fire retardant coating and fiber reinforcement material are hot-pressed in the mold for 8 minutes, thereby allowing the fire retardant coating and fiber reinforcement material to solidify and form. Step S6: Turn off the external vacuum pump, open the mold and remove the part to obtain an L-shaped molded part 300.

[0042] Example 3 Taking the molded coil forming part 300 as an example, its product thickness is 1mm, length is 1200mm, width is 2400mm, weight is 4.47kg, and it can be rolled up. It is used for multi-layer winding of irregularly shaped components to form a fireproof layer, such as... Figure 5 As shown.

[0043] Step S1: Heat the upper mold plate 100 and lower mold plate 200 of the mold by passing high temperature heat transfer oil through them, and maintain the temperature of the mold and the molding cavity 210 at 100℃. Step S2: Lay the chopped fiberglass mat flat in the molding cavity 210, then close the mold and maintain the closing pressure at 18MPa. Step S3: Mix approximately 4.55 kg of the reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine with any one of ammonium pentaborate hydrate, ethylene oxide, or ammonium polyphosphate in a vacuum environment at a ratio of 4:1. The stirring temperature is 50°C, the stirring time is 5 min, and the vacuum pressure is preferably 3 MPa. Open the overflow hole 120 and inject the fire retardant coating into the molding cavity 210 through the injection hole 110 until some of the fire retardant coating overflows from the overflow hole 120, then stop the injection. Step S4: Close the injection hole 110 and the overflow hole 120. The external vacuum pump evacuates the molding cavity 210 through the vacuum hole 220 to 3MPa and then stops to remove the air in the molding cavity 210. Step S5: While maintaining the temperature of the molding cavity 210 at 100°C and the mold closing pressure at 18MPa, the fire retardant coating and fiber reinforcement material are hot-pressed in the mold for 8 minutes, thereby allowing the fire retardant coating and fiber reinforcement material to solidify and form. Step S6: Turn off the external vacuum pump, open the mold and remove the part to obtain the coil forming part 300.

[0044] The above embodiments are preferred embodiments of this application, but the implementation of this application is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of this application shall be considered equivalent substitutions and shall be included within the protection scope of this application.

Claims

1. A molding method, characterized in that, Includes the following steps: Heat the mold to the preset temperature and keep it warm; The fiber-reinforced material is placed in the molding cavity of the mold, and the mold is closed and the fiber-reinforced material is pressed tightly. Fire-retardant coating is injected into the molding cavity; The molding cavity is evacuated; Maintain a constant temperature and pressure in the molding cavity to allow the fire-retardant coating and the fiber-reinforced material to cure and solidify.

2. The molding method according to claim 1, characterized in that, The step of placing the fiber-reinforced material into the molding cavity of the mold, closing the mold and pressing the fiber-reinforced material includes: The mold closing pressure is set to 15MPa~20MPa.

3. The molding method according to claim 1, characterized in that, The step of injecting the fire-retardant coating into the molding cavity includes: The base material and flame retardant are stirred and mixed in a vacuum environment according to a predetermined ratio to obtain the fireproof coating; Maintaining a constant temperature and pressure in the molding cavity, the fire-retardant coating is injected into the molding cavity.

4. The molding method according to claim 3, characterized in that, The fire-retardant coating is obtained by stirring and mixing the base material and the flame retardant in a vacuum environment at a predetermined ratio, comprising: The base material is set as a reaction product of C18-unsaturated dimer fatty acid and polyethyleneamine; The flame retardant is set as any one of ammonium pentaborate hydrate, ethylene oxide, or ammonium polyphosphate. The ratio of the base material to the flame retardant is set to 3.6:1 to 4.4:

1.

5. The molding method according to claim 3, characterized in that, The fire-retardant coating is obtained by stirring and mixing the base material and the flame retardant in a vacuum environment at a predetermined ratio, comprising: Set the stirring temperature to 45℃~55℃, the stirring time to 5min, and the vacuum degree to 1MPa~5MPa.

6. The molding method according to claim 1, characterized in that, The process of evacuating the molding cavity includes: The vacuum level of the molding cavity is set to 1MPa~5MPa.

7. The molding method according to claim 1, characterized in that, Maintaining a constant temperature and pressure in the molding cavity to allow the fire-retardant coating and the fiber-reinforced material to cure and solidify includes: The curing time for the fire-retardant coating and the fiber-reinforced material in the mold is set to 5 min to 10 min.

8. The molding method according to claim 1, characterized in that, The step of heating the mold to the preset temperature and maintaining the temperature includes: Heat transfer oil is continuously supplied into the mold to heat the mold and the molding cavity; After the temperature of the molding cavity reaches the preset temperature, it is kept warm.

9. The molding method according to claim 8, characterized in that: The preset temperature is set to 95℃~105℃.

10. A molded part, characterized in that: It is prepared by the compression molding method according to any one of claims 1 to 9.

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