Injection mold and injection molding method

Abstract

The invention relates to an injection mold and an injection molding method in the technical field of injection molding, the injection mold comprises: a first mold, one side of which is provided with a first mold core; the second mold is arranged on the side, provided with the first mold core, of the first mold, and a second mold core is arranged on the side, facing the first mold core, of the second mold; the ejection block is arranged around the second mold core and the first mold core, and a cavity is formed in the area defined by the second mold core, the first mold core and the ejection block; the ejector block can stretch out and draw back in the direction from the second mold to the first mold. According to the injection mold and the injection molding method, low-residual-stress and high-molding-precision molding of the optical-grade intermediate layer can be achieved, and one-time molding of the intermediate layer for large-curvature and variable-thickness laminated glass can be achieved.

Description

Technical Field

[0001] The present application relates to the technical field of injection molding, and in particular to an injection mold and an injection molding method. Background Art

[0002] The middle layer of laminated glass is often used in the form of film and laminated with glass for hot pressing. The middle layer film used in laminated glass can absorb impact energy, prevent glass fragments from splashing and prevent penetration, giving the sandwich structure transparent parts safety characteristics. At present, the middle layer is mostly prepared by extrusion molding, the product structure is single, mostly sheet, the thickness is generally difficult to exceed 2mm, and it is difficult to accurately fit with the glass when stacked in large curvature and special-shaped parts. The process of lamination and hot pressing is difficult, and the product is prone to optical defects that affect the performance of the parts. Summary of the invention

[0003] The main purpose of the present invention is to provide an injection mold and an injection molding method, aiming to solve at least one of the above technical problems.

[0004] To achieve the above-mentioned purpose, the present invention proposes an injection mold, comprising: a first mold, a first mold core is provided on one side of the first mold; a second mold, the second mold is provided on the side of the first mold with the first mold core, and the second mold is provided with a second mold core on the side facing the first mold core; a top block, the top block is arranged around the second mold core and the first mold core, and the second mold core, the first mold core and the top block enclose an area to form a cavity; the top block can be extended and retracted along the direction of the second mold toward the first mold.

[0005] In some embodiments of the present invention, the injection mold further comprises: an elastic component, wherein the elastic component is disposed between the top block and the second mold and / or between the top block and the first mold, and the top block is extended and retracted along the direction from the second mold to the first mold by the elastic component.

[0006] In some embodiments of the present invention, the injection mold further comprises: a first internal heat transfer medium pipeline system, which is formed in the first mold core; and a second internal heat transfer medium pipeline system, which is formed in the second mold core.

[0007] In some embodiments of the present invention, the injection mold further comprises: a third internal heat transfer medium pipeline system, wherein the third internal heat transfer medium pipeline system is formed in the top block.

[0008] In some embodiments of the present invention, the injection mold further comprises: a blowing mechanism, wherein the blowing mechanism is connected between the molding surface of the first mold core and the mold cavity and / or is connected between the molding surface of the second mold core and the mold cavity.

[0009] In some embodiments of the present invention, the molding surface of the first mold core and / or the molding surface of the second mold core is provided with a coating.

[0010] In some embodiments of the present invention, the injection mold further comprises: a heat insulation structure, wherein the heat insulation structure is provided on the back side of the first mold core and / or the back side of the second mold core and / or the side surface of the top block.

[0011] In some embodiments of the present invention, the top block includes more than two sub-top blocks, and the two or more sub-top blocks are connected end to end to form a ring-shaped top block.

[0012] To achieve the above object, the present invention also proposes an injection molding method, comprising the following steps:

[0013] Mold closing and preheating: according to the set cavity gap, the first mold and the second mold are brought close to each other, and the molds are closed to the set cavity gap position, which is the compression starting position; the internal heat transfer medium pipeline system arranged in the first mold core, the second mold core and the top block is used to heat the molding surface of the mold with a high-temperature heat transfer medium to reach the preset mold temperature;

[0014] Cavity drying: Dry air is sprayed out through the blowing mechanism to continuously purge the cavity, so that the moist air in the cavity is discharged;

[0015] Melt filling: When the mold preheating temperature reaches the set value and the moist air in the cavity is discharged, the melt is injected into the cavity;

[0016] Compression: During or after the melt filling process, the first mold and / or the second mold is driven in a specified direction at a set compression speed, so that the top block is compressed, the distance between the first mold core and the second mold core is reduced, the material in the cavity is compressed, and the mold is closed to the final position;

[0017] In-mold annealing: Set the mold heating temperature according to the time period to perform in-mold annealing;

[0018] Cooling: After the in-mold annealing is completed, the internal heat transfer medium pipeline system is switched to a low-temperature heat transfer medium to reduce the mold temperature to the required mold opening temperature;

[0019] Mold opening: At the moment of mold opening, dry gas is blown into the space between the part and the molding surface through the blowing mechanism, and then the mold is opened to take out the part.

[0020] In some embodiments of the present invention, the material of the melt is selected from one or more of thermoplastic polyurethane, polyvinyl butyral, and ethylene-polyvinyl acetate copolymer.

[0021] Compared with the prior art, the present invention achieves the following technical effects:

[0022] 1. The compression step of the present invention can solve the problem that when the elastomer is injected, the holding pressure decays rapidly along the flow direction of the melt due to the compressibility of the melt and the product itself, making it difficult to obtain a product with high dimensional accuracy by holding the pressure. Compression can ensure that the product is evenly subjected to pressure, thereby ensuring the density and high dimensional accuracy of the product.

[0023] 2. In the present invention, by changing the mold temperature of the product, high mold temperature can be used to achieve low-pressure injection at a lower melt temperature, thereby avoiding high temperature and high shear force from damaging the structure of the polyurethane and affecting product performance.

[0024] 3. In the present invention, by setting different mold temperatures, the molded product can be subjected to in-mold restricted annealing in the mold cavity, thereby reducing the molecular orientation and flow internal stress generated by the melt flow, improving the uniformity of the product structure, and ensuring its excellent optical quality and dimensional stability.

[0025] 4. In the present invention, after the in-mold annealing is completed, the temperature is lowered to a suitable mold opening temperature, so that smooth mold opening can be ensured.

[0026] 5. The design of the through-hole first core, the second core and the top block of the present invention can realize high-precision manufacturing of the middle layer sandwich according to a specific shape and thickness, improve the uniformity of the middle layer film structure, and ensure its excellent performance.

[0027] 6. The method for manufacturing an intermediate layer film for laminated glass proposed in the present invention can realize one-time molding of polyurethane intermediate layer films of different thicknesses and specific shapes, which solves the problem that the film is difficult to spread along the shape when laminating large-curvature and special-shaped laminated parts, is prone to wrinkles, and causes optical defects. It also solves the problem that the film must be stacked when the intermediate layer is required to be thicker, avoids the bonding interface between different layers of film, and greatly reduces the possibility of lamination defects. At the same time, it improves the dimensional accuracy of the product, effectively expands the application range of the intermediate layer film, and reduces the cost of products, molds and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0029] Figure 1 It is a structural schematic diagram of the first mold of the present invention;

[0030] Figure 2It is a schematic diagram of the distribution of the first internal heat transfer medium pipeline system of the present invention;

[0031] Figure 3 is a structural schematic diagram of the second mold of the present invention;

[0032] Figure 4 is a schematic diagram of the distribution of the second internal heat transfer medium pipeline system of the present invention;

[0033] Figure 5 It is a schematic diagram of the three-dimensional dimensional accuracy test of the workpiece of Example 1.

[0034] The reference numerals in the accompanying drawings represent as follows: 1. first mold core; 2. first air blowing mechanism; 3. glue inlet; 4. first internal heat transfer medium pipeline system; 5. second mold core; 6. top block; 61. sub-top block; 7. second air blowing mechanism; 8. elastic component; 9. third internal heat transfer medium pipeline system; 10. second internal heat transfer medium pipeline system. DETAILED DESCRIPTION

[0035] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0036] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0037] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0038] The present application embodiment discloses an injection mold. Figure 1 and Figure 3 As shown, the injection mold includes a first mold, a second mold and a top block 6 .

[0039] Among them, a first mold core 1 is provided on one side of the first mold; the second mold is provided on the side of the first mold with the first mold core 1, and a second mold core 5 is provided on the side of the second mold facing the first mold core 1; the top block 6 is arranged around the second mold core 5 and the first mold core 1, and the second mold core 5, the first mold core 1 and the top block 6 enclose an area to form a cavity; the top block 6 can be extended and retracted along the direction of the second mold toward the first mold.

[0040] In the present invention, according to the set cavity gap, the first mold and the second mold are closed to the set cavity gap position, and the position is used as the compression starting position, and the molten resin is injected into the cavity. In the middle of the melt filling process or after the filling, according to the retractability of the top block 6 between the first mold and the second mold, the first mold and / or the second mold are driven in a specified direction at a set compression speed to compress the resin in the cavity, so that the molds are closed to the final position, and then the molds can be opened to take out the parts.

[0041] The compression step of the present invention can ensure that the product is evenly subjected to pressure, ensure the density of the product and high dimensional accuracy, and effectively solve the problem that when the elastomer is injected, the holding pressure decays rapidly along the flow direction of the melt due to the compressibility of the melt and the product itself, and it is difficult to obtain a product with high dimensional accuracy by holding the pressure. The present invention can realize the one-time molding of the middle layer of laminated glass of different thicknesses and specific shapes, and can better complete the lamination of large-curvature and special-shaped laminated products. The film follows the shape and avoids wrinkles, and has excellent optical quality. When the middle layer is required to be thicker, the film does not need to be stacked, which avoids the bonding interface between different layers of film, greatly reduces the possibility of lamination defects, effectively expands the application range of the middle layer film, and reduces the cost of products, molds and equipment.

[0042] In some embodiments of the present invention, Figure 1 and Figure 3 As shown, the first mold is set as a fixed mold, the first mold core 1 is set as a fixed mold core, the second mold is set as a movable mold, the second mold core 5 is set as a movable mold core, and the second mold is movably installed along the direction of the second mold toward the first mold, so that as the second mold moves toward the direction of the first mold, the second mold can be combined with the first mold or can be separated from the first mold.

[0043] In other embodiments, the second mold can also be set as a fixed mold, and the first mold can be set as a movable mold. The first mold can be movably installed in the direction from the first mold to the second mold, so that as the first mold moves in the direction of the second mold, the first mold can be combined with the second mold or can be separated from the second mold.

[0044] In some embodiments of the present invention, the first mold core 1 and the second mold core 5 are configured to be detachably mounted on the first mold and the second mold.

[0045] In some embodiments of the present invention, Figure 1 and Figure 2 As shown, a glue inlet 3 is formed on the first mold, and the glue inlet 3 is connected with the mold cavity by the molding surface of the first mold core 1. After the initial mold closing, the glue injection device (not shown) can inject molten resin into the mold cavity through the glue inlet 3, and after the final mold closing, the resin is compressed in the mold cavity to finally form a product.

[0046] In other embodiments, the glue inlet 3 may also be opened on the second mold, and the glue inlet 3 is connected to the mold cavity through the molding surface of the second mold core 5 .

[0047] It should be noted that the number of injection channels of the mold of the present invention can be reasonably selected according to actual needs. In addition, the glue injection device can be an ordinary single-screw injection molding device.

[0048] In some embodiments of the present invention, Figure 4 As shown, the injection mold further includes an elastic component 8, which is disposed between the top block 6 and the second mold and / or between the top block 6 and the first mold. The elastic component 8 enables the top block 6 to extend and retract along the direction from the second mold to the first mold.

[0049] In this embodiment, the elastic component 8 is disposed between the top block 6 and the second mold, and the top block 6 is telescopically connected to the second mold via the elastic component 8 .

[0050] It should be understood that when the second mold and the first mold are closed, the second mold together with the elastic component 8 and the top block 6 thereon move toward the direction of the first mold until the first mold and the second mold are closed to the set cavity gap position. In the middle of the melt filling process or after filling, the second mold continues to move toward the direction of the first mold, and the elastic component 8 is compressed between the second mold and the first mold, thereby realizing the extension and retraction of the top block 6 along the direction of the second mold toward the first mold.

[0051] It should be noted that, in other embodiments, the elastic component 8 can also be arranged between the top block 6 and the first mold according to actual needs, or the elastic component 8 can be divided into two groups, one group is installed on the first mold, and the other group is installed on the second mold, and the top block 6 is connected to the corresponding mold through one group of elastic components 8.

[0052] Furthermore, the elastic component 8 includes but is not limited to a spring, an elastic pad, etc., and the elastic component 8 is preferably a nitrogen spring.

[0053] In some embodiments of the present invention, Figure 2 and Figure 4 As shown, the injection mold further includes a first internal heat transfer medium pipeline system 4 and a second internal heat transfer medium pipeline system 10 .

[0054] The first internal heat transfer medium pipeline system 4 is formed in the first mold core 1 ; and the second internal heat transfer medium pipeline system 10 is formed in the second mold core 5 .

[0055] After the first mold and the second mold are initially closed, the mold molding surface can be heated by using a high-temperature heat transfer medium through the first internal heat transfer medium pipeline system 4 in the first mold core 1 and the second internal heat transfer medium pipeline system 10 in the second mold core 5 to reach a preset mold temperature, thereby making it possible to use a high mold temperature to achieve low-pressure injection at a lower melt temperature, thereby avoiding damage to the resin structure caused by high temperature and high shear force, thereby affecting product performance.

[0056] Furthermore, by setting different mold temperatures through the first internal heat transfer medium piping system 4 and the second internal heat transfer medium piping system 10, it is possible to achieve in-mold restricted annealing of the workpiece in the cavity, reduce the molecular orientation and flow internal stress generated by the melt flow, improve the uniformity of the workpiece structure, ensure its excellent optical quality and dimensional stability, and ensure its excellent performance.

[0057] Furthermore, after the in-mold annealing is completed, different mold temperatures are set through the first internal heat transfer medium pipeline system 4 and the second internal heat transfer medium pipeline system 10 to reduce the mold to a suitable mold opening temperature, thereby ensuring smooth mold opening.

[0058] In some embodiments of the present invention, Figure 4 As shown, the injection mold further includes a third internal heat transfer medium pipeline system 9 formed in the top block 6 .

[0059] The use of the third internal heat transfer medium pipeline system 9 in conjunction with the first internal heat transfer medium pipeline system 4 and the second internal heat transfer medium pipeline system 10 can further enhance the precise control of the mold temperature, thereby further enhancing the quality of the manufactured product.

[0060] In some embodiments of the present invention, the first internal heat transfer medium pipeline system 4, the second internal heat transfer medium pipeline system 10 and the third internal heat transfer medium pipeline system 9 can be formed by processing pipelines inside the first core mold 1, the second core mold 5 and the top block 6, respectively, and the first internal heat transfer medium pipeline system 4, the second internal heat transfer medium pipeline system 10 and the third internal heat transfer medium pipeline system 9 can supply heat transfer medium independently (in parallel) or in series.

[0061] Furthermore, the internal pipelines of the first mold core 1, the second mold core 5 and the top block 6 can be designed according to the shape and / or thickness of the workpiece to achieve temperature uniformity or temperature differentiation control of the temperature of each area in the cavity.

[0062] In some embodiments of the present invention, Figure 2 and Figure 4 As shown, the injection mold further includes a blowing mechanism, which is connected between the molding surface of the first mold core 1 and the mold cavity and / or between the molding surface of the second mold core 5 and the mold cavity.

[0063] In this embodiment, the injection mold is provided with a first blowing mechanism 2 on the first mold core 1 , and a second blowing mechanism 7 on the second mold core 5 .

[0064] On the one hand, after the mold is closed, for example, when the mold is preheated, dry gas can be sprayed through the blowing mechanism of the mold to continuously blow the cavity to discharge the humid air in the cavity. Through exploratory experiments, it is found that air humidity has a significant effect on the molding process stability and performance of the intermediate layer film. Therefore, by keeping the cavity dry during molding, the quality of the product can be significantly improved.

[0065] On the other hand, since the middle layer materials are mostly highly elastic at room temperature, after the injection compression process, the part is in close contact with the mold surface and vacuum adsorption occurs, making it difficult to open the mold smoothly. Therefore, at the moment of mold opening, dry gas can be blown into the space between the part and the molding surface through the blowing mechanism to overcome the vacuum adsorption between the part and the mold surface, making it easier to open the mold and remove the part, thereby improving the demolding efficiency of the part.

[0066] In some embodiments of the present invention, through holes penetrating the core wall thickness can be processed in the first core 1 and the second core 5, and air caps or air needles can be installed in the through holes to form a blowing mechanism to ensure that the end face of the blowing mechanism is flush with the molding surface.

[0067] Furthermore, the number, size and position of the through holes on the first mold core 1 and the second mold core 5 can be reasonably set according to the molded product, so as to better dry the cavity and demold the product.

[0068] In some embodiments of the present invention, the molding surface of the first mold core 1 and / or the molding surface of the second mold core 5 is provided with a coating (not shown).

[0069] In this embodiment, the core molding surface may be subjected to special hardening and anti-sticking treatment to form a coating. Specifically, a hardening and anti-sticking coating such as a chromium nitride coating may be used to ensure the life of the mold and facilitate demolding of the workpiece.

[0070] In some embodiments of the present invention, the injection mold further includes a heat insulation structure (not shown), which is disposed on the back side of the first mold core 1 and / or the back side of the second mold core 5 and / or the side of the top block 6 .

[0071] In this embodiment, air insulation or insulation material insulation can be used to form an insulation structure, thereby reducing the heat exchange between the mold core and the top block 6 and the mold frame, ensuring the mold heating and cooling speed and reducing the deviation between the actual temperature and the set temperature.

[0072] In some embodiments of the present invention, Figure 3 and Figure 4 As shown, the top block 6 includes more than two sub-top blocks 61 , and the two or more sub-top blocks 61 are connected end to end to form a ring-shaped top block 6 .

[0073] In this embodiment, a rectangular ring-shaped top block 6 is formed by four sub-top blocks 61 to surround the first mold core 1 and the second mold core 5 to form a cavity. The overall top block 6 is formed by splicing multiple sub-top blocks 61. The processing technology is simple and can reduce the processing difficulty and cost.

[0074] It should be noted that one third internal heat transfer medium pipeline system 9 may be provided in each sub-top block 61 .

[0075] In some embodiments of the present invention, the first core 1, the second core 5 and the top block 6 of the mold can be manufactured using high-strength, high-thermal conductivity materials, such as aviation 7 series aluminum alloy or high-performance beryllium copper. Aviation 7 series aluminum alloys such as 7050 aluminum alloy can be used. When the mold is heated and cooled by using a heat transfer medium, the material with high thermal conductivity can achieve rapid temperature changes on the mold surface and improve the uniformity of the molding surface temperature.

[0076] The present application also discloses an injection molding method, which uses the above-mentioned injection mold to prepare a product, and the injection molding method includes the following steps:

[0077] (1) Mold closing and preheating: According to the set cavity gap, the first mold and the second mold are moved closer to each other, and the molds are closed to the set cavity gap position, which is the compression starting position; the internal heat transfer medium pipeline system arranged in the first mold core 1, the second mold core 5 and the top block 6 is used to heat the molding surface of the mold using a high-temperature heat transfer medium to reach the preset mold temperature.

[0078] (2) Cavity drying: Dry gas is sprayed out through the blowing mechanism to continuously blow the cavity to discharge the moist air in the cavity.

[0079] (3) Melt filling: When the mold preheating temperature reaches the set value and the moist air in the cavity is discharged, the melt is injected into the cavity.

[0080] (4) Compression: During or after the melt filling process, the first mold and / or the second mold is driven in a specified direction at a set compression speed, so that the top block 6 is compressed, the distance between the first mold core 1 and the second mold core 5 is reduced, the material in the cavity is compressed, and the mold is closed to the final position.

[0081] (5) In-mold annealing: Set the mold heating temperature according to the time period and perform in-mold annealing.

[0082] (6) Cooling: After the in-mold annealing is completed, the internal heat transfer medium pipeline system is switched to a low-temperature heat transfer medium to reduce the mold temperature to the required mold opening temperature.

[0083] (7) Mold opening: At the moment of mold opening, dry gas is blown into the space between the part and the molding surface through the blowing mechanism, and then the mold is opened to take out the part.

[0084] In some embodiments of the present invention, cavity drying and mold preheating can be performed simultaneously.

[0085] In some embodiments of the present invention, the melt material is selected from one or more of thermoplastic polyurethane, polyvinyl butyral, and ethylene-polyvinyl acetate copolymer.

[0086] The injection molding method for preparing a product using the above-mentioned injection mold in the present application will be further described below in conjunction with specific embodiments.

[0087] Example 1

[0088] The polyurethane used in this embodiment is produced by Lubrizol, USA, with a brand number of 58213. The molding equipment is a KM-CX-130 / 750 injection molding machine produced by Krauss Maffei, Germany. The target product size manufactured by the injection mold in this embodiment is 550mm*300mm*4mm.

[0089] The method for injection molding the intermediate layer of laminated glass proposed by the present invention comprises the following steps:

[0090] (1) Mold closing and preheating: The final thickness of the molded product in this embodiment is 4 mm, wherein the cavity gap is set to 2 mm. According to the set cavity gap, the movable mold is moved toward the fixed mold side to close the mold, and the mold is closed to the predetermined compression starting position, that is, the gap in the cavity is 6 mm. The mold molding surface is preheated by high-temperature and high-pressure hot water through the pipelines set in the movable mold core, the fixed mold core and the top block to reach the preset mold temperature of 110°C.

[0091] (2) Cavity drying: While preheating the mold, dry nitrogen is sprayed through the mold's blowing mechanism to continuously purge the cavity, thereby expelling the humid air in the cavity.

[0092] (3) Melt filling: When the mold preheating temperature reaches 110°C, stop nitrogen purging and inject molten polyurethane resin into the cavity at a speed of 5 mm / s. The polyurethane melt temperature is 160°C and the melt injection volume is 70 cm 3 .

[0093] (4) Compression: After the melt filling is completed, the injection molding machine clamping unit drives the movable mold to move 2 mm toward the fixed mold at a speed of 1 mm / s, so that the mold is clamped to the final position to compress the resin in the cavity.

[0094] (5) In-mold annealing: After the compression is completed, the variable mold temperature system is used to quickly switch the high-temperature water in the pipeline and introduce circulating water with a lower temperature to reduce the mold temperature to 80°C and keep it warm for 5 minutes, thereby achieving in-mold annealing.

[0095] (6) Cooling: After the in-mold annealing is completed, the high-temperature water in the mold pipeline is switched to low-temperature water using the variable mold temperature system, so that the mold temperature drops to 30°C, and the cooling process time is ensured to be no less than 3 minutes.

[0096] (7) Mold opening: At the moment of mold opening, dry nitrogen is blown into the space between the part and the molding surface through the blowing mechanism on the movable mold side (the first blowing mechanism), with a blowing pressure of 0.6 MPa and a blowing duration of 5 seconds, to ensure that the part is separated from the movable mold side and adsorbed on the fixed mold side. Then the mold is opened, and dry nitrogen is blown into the space between the part and the molding surface through the blowing mechanism on the fixed mold side (the second blowing mechanism), with a blowing pressure of 0.6 MPa and a blowing duration of 5 seconds, and then the part is taken out.

[0097] Test of the three-dimensional dimensional accuracy of the intermediate layer film:

[0098] like Figure 5 As shown, 10 measuring points are evenly selected at different positions of the film, and the thickness of each point is measured using a thickness gauge; the length of the workpiece is measured along the three straight lines of line 1, line 2 and line 3 using a vernier caliper; the width of the workpiece is measured along the three straight lines of line 4, line 5 and line 6 using a vernier caliper.

[0099] The dimensional deformation rate D of each measured value in three dimensions is calculated according to the following formula (1), where L1 is the actual measured value of the workpiece and L2 is the theoretical value of the workpiece. The dimensional deformation rate in the specified length direction is D L , the deformation rate in the width direction is D w , the deformation rate in the thickness direction is D h , and then calculate the average deformation rate in each direction and standard deviation S L , S w , S h , which further characterizes the dimensional accuracy of the workpiece.

[0100]

[0101] Table 1 shows the dimensional accuracy data of the injection-molded intermediate layer film. The film manufactured by this method has excellent three-dimensional dimensional accuracy and meets the use requirements.

[0102] Table 1 Three-dimensional dimensional accuracy of the polyurethane intermediate layer film obtained by injection molding

[0103]

[0104] The polyurethane intermediate layer film prepared by the above method and mold can not only achieve a thickness that is difficult to achieve by traditional extrusion molding, but also the molding accuracy of the film is guaranteed.

[0105] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An injection mold, characterized in that: include: A first mold, wherein a first mold core is provided on one side of the first mold; A second mold, wherein the second mold is arranged on a side of the first mold with the first mold core, and a second mold core is arranged on a side of the second mold facing the first mold core; A top block, wherein the top block is arranged around the second mold core and the first mold core, and the second mold core, the first mold core and the top block enclose an area to form a mold cavity; The top block can be extended and retracted along the direction of the second mold toward the first mold.

2. The injection mold according to claim 1, characterized in that Also includes: An elastic component is provided between the top block and the second mold and / or between the top block and the first mold, and the top block is extended and retracted along the direction from the second mold to the first mold by the elastic component.

3. The injection mold according to claim 1, characterized in that Also includes: a first internal heat transfer medium pipeline system, wherein the first internal heat transfer medium pipeline system is formed in the first mold core; A second internal heat transfer medium pipeline system is formed in the second mold core.

4. The injection mold according to claim 3, characterized in that Also includes: A third internal heat transfer medium pipeline system is formed in the top block.

5. The injection mold according to claim 1, characterized in that Also includes: An air blowing mechanism, wherein the air blowing mechanism is connected to the mold cavity through the molding surface of the first mold core and / or is connected to the mold cavity through the molding surface of the second mold core.

6. The injection mold according to claim 1, characterized in that The molding surface of the first mold core and / or the molding surface of the second mold core is provided with a coating.

7. The injection mold according to claim 1, characterized in that Also includes: A heat insulation structure is provided on the back side of the first mold core and / or the back side of the second mold core and / or the side surface of the top block.

8. The injection mold according to claim 1, characterized in that The top block includes more than two sub-top blocks, and the two or more sub-top blocks are connected end to end to form a ring-shaped top block.

9. An injection molding method, characterized in that: The steps include: Mold closing and preheating: according to the set cavity gap, the first mold and the second mold are brought close to each other, and the molds are closed to the set cavity gap position, which is the compression starting position; the internal heat transfer medium pipeline system arranged in the first mold core, the second mold core and the top block is used to heat the molding surface of the mold with a high-temperature heat transfer medium to reach the preset mold temperature; Cavity drying: Dry air is sprayed out through the blowing mechanism to continuously purge the cavity, so that the moist air in the cavity is discharged; Melt filling: When the mold preheating temperature reaches the set value and the moist air in the cavity is discharged, the melt is injected into the cavity; Compression: During or after the melt filling process, the first mold and / or the second mold is driven in a specified direction at a set compression speed, so that the top block is compressed, the distance between the first mold core and the second mold core is reduced, the material in the cavity is compressed, and the mold is closed to the final position; In-mold annealing: Set the mold heating temperature according to the time period to perform in-mold annealing; Cooling: After the in-mold annealing is completed, the internal heat transfer medium pipeline system is switched to a low-temperature heat transfer medium to reduce the mold temperature to the required mold opening temperature; Mold opening: At the moment of mold opening, dry gas is blown into the space between the part and the molding surface through the blowing mechanism, and then the mold is opened to take out the part.

10. The injection molding method according to claim 9, characterized in that: The material of the melt is selected from one or more of thermoplastic polyurethane, polyvinyl butyral, and ethylene-polyvinyl acetate copolymer.

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