A composite mold for automotive interior trim flanging machine and its manufacturing method

Abstract

This invention discloses a composite mold for an automotive interior trim flanging machine and its manufacturing method, belonging to the technical field of automotive interior product molds. The composite mold mainly includes an upper mold part and a lower mold part. The lower mold part mainly includes three parts: the mold body, a polyurethane buffer layer, and a silicone buffer layer. By forming a double-layer elastic buffer structure on the surface of the lower mold, stress buffering can be provided for the pressure generated during the mold closing process of the integral pressing mold. This solves the problem of damage to areas with excessive curvature of the surface skin caused by uneven overall pressure when the surface skin thickness is less than 1mm in existing flanging machine molds, greatly reducing the product scrap rate. In addition, in the manufacturing method of this invention, the polyurethane material is not fully cured when the silicone material is sprayed, and it has a certain degree of adhesion. This property ensures good adhesion performance with the subsequently sprayed silicone material, which can guarantee the stability of the composite structure.

Description

Technical Field

[0001] This invention relates to the field of automotive interior product flanging machine mold technology, and in particular to a composite mold for automotive interior product flanging machine and its manufacturing method. Background Technology

[0002] As my country's automotive industry moves towards high-end and intelligent development, consumers are placing higher demands on the aesthetic quality, tactile experience, and environmental performance of interior trim. As components that come into direct contact with drivers and passengers, the selection of materials, molding processes, and defect control for interior trim have become key areas of technological breakthroughs for the industry.

[0003] During the molding process of automotive interior panels, when the thickness of the panels is less than 1mm (ultra-thin panels), uneven overall pressure can cause defects such as breakage in areas with excessive curvature (e.g., the strain concentration coefficient in double-curvature areas like door panel armrest grooves can reach 3.2), reducing the yield rate of ultra-thin panels.

[0004] With advancements in materials science and intelligent manufacturing, the yield rate of ultra-thin skin molding needs to be further improved. Summary of the Invention

[0005] This invention addresses the problem that existing flanging machine molds, when the surface thickness is less than 1mm, suffer damage in areas with excessive surface curvature due to uneven overall pressure. It proposes a composite mold for automotive interior flanging machines and its manufacturing method.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, this invention proposes a method for manufacturing a composite mold for an automotive interior trim flanging machine. The method involves spraying or brushing a layer of rigid polyurethane onto the surface of a lower mold and curing it at 60-80°C for 1-3 hours. Then, a layer of silicone is sprayed onto the surface of the partially cured rigid polyurethane buffer layer and cured at 100-120°C for 4-6 hours, resulting in a lower mold with a double-layer elastic buffer structure. The rigid polyurethane is obtained by mixing polyurethane prepolymer and 4,4'-methylenebis(2-chloroaniline) at a mass ratio of 100:(12.5-13.5). The cured rigid polyurethane buffer layer has a thickness of 120-160 micrometers and a Shore A hardness of 80-90. The silicone buffer layer has a thickness of 150-180 micrometers and a Shore A hardness of 60-70.

[0008] Preferably, the manufacturing method of the above-mentioned composite mold for automotive interior trim flanging machine includes the following steps:

[0009] S1: Sandblast the surface of the lower mold.

[0010] S2: Clean the surface of the mold after sandblasting with a high-pressure water gun, and then dry it;

[0011] S3: Spray or brush a layer of rigid polyurethane onto the dried mold surface, and then cure it at 60-80℃ for 1-3 hours to obtain a rigid polyurethane buffer layer.

[0012] S4: Spray a layer of silicone onto the surface of the cured rigid polyurethane buffer layer, and then cure at 100-120℃ for 4-6 hours to obtain the silicone buffer layer.

[0013] Preferably, the mass ratio of the polyurethane prepolymer to 4,4'-methylenebis(2-chloroaniline) is 100:13.

[0014] Preferably, the thickness of the rigid polyurethane buffer layer after curing is 140 micrometers, and the Shore A hardness is 85.

[0015] Preferably, the rigid polyurethane buffer layer is cured at a temperature of 70°C for 2 hours.

[0016] Preferably, the thickness of the silicone buffer layer is 160 micrometers and the Shore A hardness is 65.

[0017] Preferably, the curing temperature of the silicone is 110°C and the curing time is 5 hours.

[0018] Preferably, the manufacturing method of the above-mentioned composite mold for automotive interior trim flanging machine includes the following steps:

[0019] S1: Sandblast the surface of the lower mold.

[0020] S2: The surface of the mold after sandblasting is cleaned with a high-pressure water gun and then dried;

[0021] S3: Spray or brush a layer of rigid polyurethane onto the dried mold surface, and then cure it at 70°C for 2 hours to obtain a rigid polyurethane buffer layer; the thickness of the cured rigid polyurethane buffer layer is 140 micrometers and the Shore A hardness is 85; in the rigid polyurethane, the mass ratio of polyurethane prepolymer to 4,4'-methylenebis(2-chloroaniline) is 100:13.

[0022] S4: Spray a layer of silicone onto the surface of the cured rigid polyurethane buffer layer, and then cure it at 110℃ for 5 hours to obtain a silicone buffer layer. The thickness of the cured silicone buffer layer is 160 micrometers and the Shore A hardness is 65.

[0023] Secondly, the present invention provides a composite mold for an automotive interior trim flanging machine, wherein the lower mold is manufactured using any of the above-described manufacturing methods.

[0024] Compared with the prior art, the technical effects of the present invention are as follows:

[0025] The composite mold for automotive interior flanging machines and its manufacturing method proposed in this invention, through exploring the optimal ratio of polyurethane buffer layer materials (controlling crosslinking density) and the optimal combination of process parameters for the preparation of polyurethane and silicone buffer layers (ensuring leveling, maximizing interfacial bonding force, and achieving double crosslinking), forms a double-layer elastic buffer structure on the surface of the lower mold. This structure can buffer the stress generated during the molding process of the integral pressing mold, effectively dispersing local stress and thus avoiding defects such as skin breakage caused by stress concentration in individual areas, significantly reducing the product scrap rate. This invention has significant innovation in solving the stress concentration and breakage problems in the molding process of ultra-thin skins (thickness <1mm), and is particularly suitable for complex interior parts of high-end models (such as floating dashboards and three-dimensional wrapped door panels), adapting to more demanding styling designs.

[0026] Furthermore, in the method for manufacturing the composite mold of the automotive interior trim flanging machine proposed in this invention, when the silicone material is sprayed, the polyurethane material is not fully cured in the gel stage and has a certain surface activity. This property ensures that it has good adhesion to the subsequently sprayed silicone material, forming a molecular-level interpenetrating network (IPN structure) and ensuring the stability of the composite structure. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram of the method for manufacturing a composite mold for a flanging machine provided in an embodiment of the present invention.

[0029] Figure 2 The flowchart illustrates the manufacturing process of the composite mold for the flanging machine provided in this embodiment of the invention.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Upper mold part; 2. Lower mold part; 3. Rigid polyurethane buffer layer; 4. Silicone buffer layer. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0034] Unless otherwise specified, all experimental materials used in the following examples were purchased from conventional biochemical reagent stores.

[0035] like Figure 1 As shown, the composite mold mainly includes an upper mold part 1 and a lower mold part 2. The manufacturing method of the composite mold for the automotive interior trim flanging machine provided by the present invention includes the following steps:

[0036] S1: Sandblast the surface of the lower mold.

[0037] S2: Clean the surface of the mold after sandblasting with a high-pressure water gun, and then dry it;

[0038] S3: Spray or brush a layer of rigid polyurethane onto the dried mold surface, and then cure it at 60-80°C for 1-3 hours to obtain rigid polyurethane buffer layer 3. Preferably, the curing temperature of the rigid polyurethane buffer layer is 70°C and the curing time is 2 hours. The rigid polyurethane is obtained by mixing polyurethane prepolymer and 4,4'-methylenedi(2-chloroaniline) at a mass ratio of 100:(12.5-13.5); preferably, the mass ratio of the polyurethane prepolymer and 4,4'-methylenedi(2-chloroaniline) is 100:13. The thickness of the cured rigid polyurethane buffer layer is 120-160 micrometers, and the Shore A hardness is 80-90; preferably, the thickness of the cured rigid polyurethane buffer layer is 140 micrometers, and the Shore A hardness is 85.

[0039] S4: Spray a layer of silicone onto the surface of the cured rigid polyurethane buffer layer, and then cure it at 100-120℃ for 4-6 hours to obtain silicone buffer layer 4. The thickness of the silicone buffer layer is 150-180 micrometers, and the Shore A hardness is 60-70. Preferably, the curing temperature of the silicone is 110℃, and the curing time is 5 hours. Preferably, the thickness of the silicone buffer layer is 160 micrometers, and the Shore A hardness is 65.

[0040] The main materials used in the embodiments of the present invention are shown in Table 1.

[0041] Table 1. Information on the main materials used in the embodiments.

[0042]

[0043] The following is a detailed description using typical embodiments.

[0044] Example 1

[0045] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A 120-micron thick layer of rigid polyurethane material is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:12.5. This is cured at 60°C for 3 hours, achieving a Shore A hardness of 80. Next, a 150-micron thick layer of silicone material is sprayed onto the pre-cured surface and cured at 100°C for 6 hours, achieving a Shore A hardness of 60, thus obtaining the lower mold of the composite mold.

[0046] Example 2

[0047] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A layer of rigid polyurethane material, 130 micrometers thick, is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:13. It is cured at 70°C for 2.5 hours, achieving a Shore A hardness of 82. Next, a layer of silicone material, 160 micrometers thick, is sprayed onto the pre-cured surface and cured at 110°C for 6 hours, achieving a Shore A hardness of 62, thus obtaining the lower mold of the composite mold.

[0048] Example 3

[0049] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A layer of rigid polyurethane material, 140 micrometers thick, is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:13. It is cured at 70°C for 2 hours, achieving a Shore A hardness of 85. Next, a layer of silicone material, 160 micrometers thick, is sprayed onto the pre-cured surface and cured at 110°C for 5 hours, achieving a Shore A hardness of 65, thus obtaining the lower mold of the composite mold.

[0050] Example 4

[0051] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A 160-micron thick layer of rigid polyurethane material is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:13.5. This is cured at 80°C for 1 hour, achieving a Shore A hardness of 90. Next, a 180-micron thick layer of silicone material is sprayed onto the pre-cured surface and cured at 120°C for 4 hours, achieving a Shore A hardness of 70, thus obtaining the lower mold of the composite mold.

[0052] Comparative Example 1

[0053] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A layer of rigid polyurethane material, 170 micrometers thick, is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:13. It is cured at 80°C for 3.5 hours, achieving a Shore A hardness of 90. Next, a layer of silicone material, 160 micrometers thick, is sprayed onto the pre-cured surface and cured at 110°C for 5 hours, achieving a Shore A hardness of 65, thus obtaining the lower mold of the composite mold.

[0054] Comparative Example 2

[0055] First, the surface of the lower mold is sandblasted, then cleaned with a high-pressure water gun, and then dried (approximately 25 minutes). A layer of rigid polyurethane material, 140 micrometers thick, is then brushed onto the dried mold surface, with a polyurethane prepolymer to MOCA mass ratio of 100:13. It is cured at 70°C for 2 hours, achieving a Shore A hardness of 85. Next, a layer of silicone material, 190 micrometers thick, is sprayed onto the pre-cured surface and cured at 125°C for 6.5 hours, achieving a Shore A hardness of 75, thus obtaining the lower mold of the composite mold.

[0056] The Shore A hardness of the above materials was obtained by measuring separately prepared rigid polyurethane and silicone samples, with a thickness of 8 mm and a length and width of 20 mm.

[0057] Using a conventional upper mold and lower molds prepared in Examples 1-6, ultra-thin skins (thickness less than 1 mm) were pressed together, and the results are shown in Table 2. The results show that the lower molds prepared beyond the optimal parameter range of this application cannot effectively buffer the stress generated during the mold closing process of the integral pressing mold, and the skin will still break due to stress concentration in some areas.

[0058] Table 2 Experimental Results Information

[0059] Experimental protocol Surface condition of the skin after multiple pressings Example 1 Smooth and undamaged Example 2 Smooth and undamaged Example 3 Smooth and undamaged Example 4 Smooth and undamaged Comparative Example 1 Smooth, damaged Comparative Example 2 Smooth, damaged

[0060] In summary, by forming a double-layer elastic buffer structure on the surface of the lower mold, this invention can buffer the pressure generated during the mold closing process of the integral pressing mold, effectively disperse local stress, and solve the problem of damage to areas with excessive curvature of the skin caused by uneven overall pressure when the skin thickness of the existing flanging machine mold is less than 1mm, thus greatly reducing the product scrap rate.

[0061] Furthermore, in the manufacturing method of this invention, when the silicone material is sprayed, the polyurethane material is in the gel stage (curing degree 40-60%) and has not yet been fully cured, possessing a certain degree of viscosity (surface energy ≥35mN / m). This property ensures that it has good adhesion to the subsequently sprayed silicone material, forming a molecular-level interpenetrating network (IPN structure), with a peel strength of 8-12N / mm (compared to only 3-5N / mm in traditional bonding processes), thus ensuring the stability of the composite structure.

[0062] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a composite mold for an automotive interior trim flanging machine, characterized in that, A layer of rigid polyurethane is sprayed or brushed onto the surface of the lower mold and cured at 60-80℃ for 1-3 hours; then, a layer of silicone is sprayed onto the surface of the incompletely cured rigid polyurethane buffer layer and cured at 100-120℃ for 4-6 hours to obtain a lower mold with a double-layer elastic buffer structure; the rigid polyurethane is composed of polyurethane prepolymer and 4,4'-methylenebis(2-chloroaniline) in a mass ratio of 100: (12.5~13.5) The thickness of the rigid polyurethane buffer layer after curing is 120~160 micrometers, and the Shore A hardness is 80~90; the thickness of the silicone buffer layer is 150~180 micrometers, and the Shore A hardness is 60~70.

2. The method for manufacturing the composite mold for automotive interior trim flanging machine according to claim 1, characterized in that, Includes the following steps: S1: Sandblast the surface of the lower mold. S2: Clean the surface of the mold after sandblasting with a high-pressure water gun, and then dry it; S3: Spray or brush a layer of rigid polyurethane onto the dried mold surface, and then cure it at 60-80℃ for 1-3 hours to obtain a rigid polyurethane buffer layer. S4: Spray a layer of silicone onto the surface of the cured rigid polyurethane buffer layer, and then cure at 100-120℃ for 4-6 hours to obtain the silicone buffer layer.

3. The method for manufacturing the composite mold for the automotive interior trim flanging machine according to claim 1, characterized in that, The mass ratio of the polyurethane prepolymer to 4,4'-methylenebis(2-chloroaniline) is 100:

13.

4. The method for manufacturing the composite mold for the automotive interior trim flanging machine according to claim 1, characterized in that, The rigid polyurethane buffer layer has a thickness of 140 micrometers after curing and a Shore A hardness of 85.

5. The method for manufacturing the composite mold for the automotive interior trim flanging machine according to claim 1, characterized in that, The rigid polyurethane buffer layer is cured at 70°C for 2 hours.

6. The method for manufacturing the composite mold for an automotive interior trim flanging machine according to claim 1, characterized in that, The silicone buffer layer has a thickness of 160 micrometers and a Shore A hardness of 65.

7. The method for manufacturing the composite mold for an automotive interior trim flanging machine according to claim 1, characterized in that, The silicone is cured at 110°C for 5 hours.

8. The method for manufacturing the composite mold for automotive interior trim flanging machine according to claim 1, characterized in that, Includes the following steps: S1: Sandblast the surface of the lower mold. S2: The surface of the mold after sandblasting is cleaned with a high-pressure water gun and then dried; S3: Spray or brush a layer of rigid polyurethane onto the dried mold surface, and then cure it at 70°C for 2 hours to obtain a rigid polyurethane buffer layer; the thickness of the cured rigid polyurethane buffer layer is 140 micrometers and the Shore A hardness is 85; in the rigid polyurethane, the mass ratio of polyurethane prepolymer to 4,4'-methylenebis(2-chloroaniline) is 100:

13. S4: Spray a layer of silicone onto the surface of the cured rigid polyurethane buffer layer, and then cure it at 110℃ for 5 hours to obtain a silicone buffer layer. The thickness of the cured silicone buffer layer is 160 micrometers and the Shore A hardness is 65.

9. A composite mold for an automotive interior trim flanging machine, characterized in that, The lower mold is manufactured using the manufacturing method described in any one of claims 1-8.

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