A silicone mold for texturing mobile phone back covers and its manufacturing method

Abstract

This application relates to the technical field of texture imprinting on mobile phone back covers, and particularly to a silicone mold for texture imprinting on mobile phone back covers and its manufacturing method. The manufacturing method includes step 1: making a template by using a UV transfer machine to transfer the texture onto a PC board to form a template with an outwardly raised texture; step 2: injection molding by fixing the template into the cavity of an injection mold and injecting liquid silicone rubber into the cavity of the injection mold, heating and pressurizing the cavity of the injection mold, and curing the liquid silicone rubber in the cavity of the injection mold to obtain a silicone mold; step 3: demolding by removing the silicone mold from the injection mold. This application forms a silicone mold by injection molding with liquid silicone rubber. The method is simple to operate, and the silicone mold replaces the composite board mold. It is less prone to texture deformation when heated and has a longer service life.

Description

Technical Field

[0001] This application relates to the technical field of texture imprinting on mobile phone back covers, and more specifically, it relates to a silicone mold for texture imprinting on mobile phone back covers and a method for manufacturing the same. Background Technology

[0002] Textured designs on phone back covers enhance their aesthetics and align with market demands. Creating textures requires molds. Specifically, UV adhesive is evenly pressed onto a mold using a substrate, a template is attached to the mold, and then UV light is applied to harden the adhesive. Finally, the template is peeled off, transferring the texture from the UV adhesive onto the template. In related technologies, texture molds are created by laser engraving the texture onto composite materials. However, these technologies have the following drawbacks: using composite materials as texture molds results in a short lifespan, and the texture is prone to deformation under prolonged heat, leading to a low overall lifespan. Summary of the Invention

[0003] To address the issues of short lifespan and textural distortion caused by using composite boards as texture molds, this application provides a silicone mold for texturing mobile phone back covers and its manufacturing method.

[0004] In its first aspect, this application provides a method for manufacturing a silicone mold for texturing the back cover of a mobile phone.

[0005] A method for manufacturing a silicone mold for texturing on a mobile phone back cover includes the following steps:

[0006] Step 1: Create a template by using a UV transfer machine to transfer the texture onto a PC board to form a template with raised texture.

[0007] Step 2: Injection molding. Fix the template into the cavity of the injection mold. Inject liquid silicone rubber into the cavity of the injection mold. Heat and pressurize the cavity of the injection mold. The liquid silicone rubber solidifies and forms a silicone mold in the cavity of the injection mold.

[0008] Step 3: Demolding. Remove the silicone mold from the injection mold.

[0009] Preferably, the injection mold includes a lower mold and an upper mold. The top surface of the lower mold is recessed with a cavity. A plurality of positioning posts are vertically arranged on the top surface of the lower mold, surrounding the periphery of the cavity. The upper mold is provided with positioning grooves that slide with the positioning posts. The number of positioning grooves matches the number of positioning posts. The mold plate is provided with positioning holes through which the positioning posts pass. The number of positioning holes matches the number of positioning posts.

[0010] Preferably, the liquid silicone rubber is made from the following raw materials in parts by weight: 30-50 parts of high-viscosity vinyl silicone oil, 30-50 parts of low-viscosity vinyl silicone oil, 10-20 parts of hydrophilic fumed silica, 10-20 parts of hydrophobic fumed silica, 0.5-1 parts of platinum catalyst, 5-10 parts of hydrogen-containing silicone oil, and 0.5-1 parts of inhibitor.

[0011] Preferably, the liquid silicone rubber is prepared by the following steps:

[0012] Step S1: Add 30-50 parts by weight of high-viscosity vinyl silicone oil to a vacuum kneader, start stirring, then add 10-20 parts of hydrophilic fumed silica and 10-20 parts of hydrophobic fumed silica, mix well, then add 10-20 parts of low-viscosity vinyl silicone oil, heat to 150-160℃ and then vacuum, maintain the vacuum degree at -0.095MPa, and remove the vacuum for 1-2 hours to obtain the base adhesive;

[0013] Step S2: Divide the base adhesive obtained in step S1 into two equal parts by weight. Add 0.5-1 part of platinum catalyst to one part, mix well to obtain component A, and add 5-10 parts of hydrogen-containing silicone oil and 0.5-1 part of inhibitor to the other part, mix well to obtain component B.

[0014] Step S3: Mix component A and component B obtained in step S2 at a weight ratio of 1:1 and place them in a vacuum mixer. Stir for 15-30 minutes under a vacuum of -0.095 MPa.

[0015] Preferably, the inhibitor is ethynylcyclohexanol.

[0016] Preferably, the high-viscosity vinyl silicone oil has a viscosity of 20,000 mPa·s, and the low-viscosity vinyl silicone oil has a viscosity of 10,000 mPa·s.

[0017] Preferably, the specific surface area of ​​the hydrophilic fumed silica is 200 m², and the specific surface area of ​​the hydrophobic fumed silica is 300 m².

[0018] Preferably, in step 2, the heating temperature is 60-180℃, the pressure inside the injection mold cavity is 380-480N, and the heating and pressurizing time is 380-600s.

[0019] On the other hand, this application provides a silicone mold for imprinting texture on the back cover of a mobile phone, which is prepared by the above-described manufacturing method.

[0020] In summary, this application includes at least one of the following beneficial technical effects:

[0021] 1. Using silicone material instead of composite board to make texture molds. Texture molds made of silicone material have excellent high temperature resistance, are not easily deformed by heat, and have good chemical corrosion resistance, low shrinkage, good tensile strength, high tear resistance, and long service life.

[0022] 2. Vinyl silicone oil is the main material for injection thermoforming liquid silicone rubber. It has excellent heat resistance, cold resistance, and chemical stability, enabling the manufactured silicone molds to have excellent high-temperature resistance. High-viscosity vinyl silicone oil has higher hardness, while low-viscosity vinyl silicone oil has better flow properties. Using a reasonable ratio of high-viscosity and low-viscosity vinyl silicone oils makes it easier to obtain silicone that meets the hardness requirements and has fewer molding defects. The addition of fumed silica has good activity and adsorption rate, and good reinforcing effect. As a filler, it can help improve the tensile strength and tear strength of silicone molds. It can also be used as a defoamer to improve the dispersion efficiency of silicone oil, thereby improving the defoaming effect. Furthermore, using a reasonable ratio of hydrophilic and hydrophobic fumed silica can effectively improve the waterproof ability of silicone molds and extend their service life while keeping costs low.

[0023] 3. Using a vacuum kneader and vacuum mixer to knead and stir the liquid silicone rubber raw material under vacuum conditions helps to reduce the generation of air bubbles, resulting in liquid silicone rubber with better performance. Vacuuming in the injection mold further reduces air bubble generation when the liquid silicone rubber is molded into a silicone mold, resulting in a high-performance silicone mold. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the steps of a method for manufacturing a silicone mold for texturing the back cover of a mobile phone, as described in this application.

[0025] Figure 2 This is a schematic diagram of the structure of the injection mold and template used in this application.

[0026] Figure 3 This is a structural diagram of the template for this application.

[0027] Reference numerals: 1. Template; 11. Positioning hole; 2. Lower mold; 21. Positioning post; 3. Upper mold. Detailed Implementation

[0028] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0029] Preparation example of liquid silicone rubber

[0030] Preparation Example 1

[0031] Step S1: Add 3 kg of 20000 mpa·s vinyl silicone oil to a vacuum kneader, start stirring, then add 1 kg of hydrophilic fumed silica and 1 kg of hydrophobic fumed silica. The hydrophilic fumed silica is hydrophilic fumed silica, and the hydrophobic fumed silica is preferably hydrophobic fumed silica with a surface area of ​​20 m². After mixing, add 1 kg of 10000 mpa·s vinyl silicone oil, heat to 160°C and then vacuum, maintaining the vacuum at -0.095 MPa, and then de-vacuum for 2 hours to obtain the base adhesive.

[0032] Step S2: Divide the base adhesive obtained in step S1 into two equal parts. Add 1 kg of platinum catalyst to one part, mix well to obtain component A. Add 0.5 kg of hydrogen-containing silicone oil and 0.05 kg of inhibitor to the other part. The inhibitor is ethynylcyclohexanol. Mix well to obtain component B.

[0033] Step S3: Mix component A and component B obtained in step S2 at a weight ratio of 1:1 and place them in a vacuum mixer. Stir for 30 minutes while maintaining a vacuum of -0.095 MPa.

[0034] Preparation Examples 2-3

[0035] The differences between Preparation Examples 2-3 and Preparation Example 1 above are: differences in the types and amounts of materials used, as well as differences in process conditions, as detailed in Table 1 below.

[0036] Table 1. Material types, material quantities, and process conditions for preparation examples 1-5

[0037]

[0038]

[0039] Preparation of Comparative Example 1

[0040] The difference between Comparative Example 1 and Preparation Example 1 is that 1 kg of low-viscosity vinyl silicone oil in step S1 is replaced with 1 kg of high-viscosity vinyl silicone oil.

[0041] Preparation of Comparative Example 2

[0042] The difference between Comparative Example 2 and Comparative Example 1 is that 1 kg of hydrophobic silica in step S1 is replaced with 1 kg of hydrophilic silica.

[0043] Example

[0044] Example 1

[0045] A method for manufacturing a silicone mold for texturing on a mobile phone back cover includes the following steps:

[0046] Step 1: Create a template by using a UV transfer machine to transfer the texture onto a PC board to form a template with raised texture.

[0047] Step 2: Injection molding. The template 1 is fixed into the cavity of the injection mold. The liquid silicone rubber prepared by the method steps in Preparation Example 1 is injected into the cavity of the injection mold. The injection mold includes heating and pressurizing the cavity of the injection mold. The temperature inside the cavity is 180°C, the pressure inside the cavity is 480N, and the heating and pressurizing time is 600s. The liquid silicone rubber is cured and formed in the cavity of the injection mold to obtain a textured silicone mold.

[0048] Step 3: Demolding. Remove the silicone mold from the injection mold.

[0049] Furthermore, referring to Figure 2 and Figure 3 The injection mold includes a lower mold 2 and an upper mold 3. The top surface of the lower mold 2 is recessed with a cavity. Several positioning pins 21 are vertically arranged around the periphery of the cavity on the top surface of the lower mold 2. The upper mold 3 is provided with positioning grooves that slide with the positioning pins 21. The number of positioning grooves matches the number of positioning pins 21. The template 1 is provided with positioning holes 11 for the positioning pins to pass through. The number of positioning holes 11 matches the number of positioning pins 21. In use, the template 1 is fixed to the surface of the lower mold 2 with the raised texture facing down through the positioning pins 21. Then, the upper mold 3 is precisely covered to the lower mold 2 through the cooperation of the positioning pins and positioning grooves. The upper mold 3 tightly presses the template 1 onto the lower mold 2. The template 1 closes the cavity. Through the raised texture on the template 1, the liquid silicone rubber is molded into a silicone mold with the corresponding texture.

[0050] Example 2

[0051] The difference between Example 2 and Example 1 is that the liquid silicone rubber in Example 2 was prepared using the method steps of Example 2.

[0052] Example 3

[0053] The difference between Example 3 and Example 1 is that the liquid silicone rubber in Example 3 was prepared using the same method and steps as in Example 3.

[0054] Example 4

[0055] The difference between Example 4 and Example 1 is that the liquid silicone rubber in Example 4 was prepared using the same method and steps as in Comparative Example 1.

[0056] Example 5

[0057] The difference between Example 5 and Example 1 is that the liquid silicone rubber in Example 5 was prepared using the same method and steps as in Comparative Example 2.

[0058] Performance testing

[0059] Following the test method of GB / T531-1999 standard, the silicone mold was subjected to a hot air aging test at 100℃ for 7 hours. Then, the following test was conducted, and the test results are shown in Table 2.

[0060] 1. The hardness of the silicone mold was tested using the test method described in GB / T531-1999 test standard.

[0061] 2. The tensile strength of the silicone mold was tested using the test method described in GB / T528-1998 test standard.

[0062] 3. The elongation at break of the silicone mold was tested using the test method described in GB / T528-1998 test standard.

[0063] 4. The silicone mold shall be subjected to compression set test according to the test method described in GB / T7759-1996 test standard.

[0064] 5. The density of the silicone mold was tested using Method A of the GB / T533-2008 test standard with a silicone density meter.

[0065] 6. The heat resistance of the silicone mold shall be tested using the test methods described in GB / T3512-2001 test standard.

[0066] 7. The resilience of the silicone mold shall be tested using the test method described in GBT1681-2009 test standard.

[0067] Table 2

[0068]

[0069]

[0070] As can be seen from the experimental results in Table 2, after the hot air aging test, the hardness, tensile strength, elongation, compression ratio, density, resilience and heat resistance of the silicone mold of this application are all within the standard range. The texture on the silicone mold is not easily deformed by heat and has a long service life. The hardness of Example 4 is too high. The reason for this is that a large amount of high viscosity vinyl silicone oil was used instead of low viscosity vinyl silicone oil.

[0071] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a silicone mold for texturing on a mobile phone back cover, characterized in that, Includes the following steps: Step 1: Create a template by using a UV transfer machine to transfer the texture onto a PC board to form a template with raised texture. Step 2: Injection molding. Fix the template into the cavity of the injection mold. Inject liquid silicone rubber into the cavity of the injection mold. Heat and pressurize the cavity of the injection mold. The liquid silicone rubber solidifies and forms a silicone mold in the cavity of the injection mold. The injection mold includes a lower mold and an upper mold. The top surface of the lower mold is recessed with a cavity. A plurality of positioning pins are vertically arranged on the top surface of the lower mold and surround the periphery of the cavity. The upper mold is provided with positioning grooves that slide with the positioning pins. The number of positioning grooves matches the number of positioning pins. The mold plate is provided with positioning holes for the positioning pins to pass through. The number of positioning holes matches the number of positioning pins. The liquid silicone rubber is made from the following raw materials in parts by weight: 30-50 parts of high-viscosity vinyl silicone oil, 10-20 parts of low-viscosity vinyl silicone oil, 10-20 parts of hydrophilic fumed silica, 10-20 parts of hydrophobic fumed silica, 0.5-1 parts of platinum catalyst, 5-10 parts of hydrogen-containing silicone oil, and 0.5-1 parts of inhibitor. The liquid silicone rubber is prepared by the following steps: Step S1: Add 30-50 parts by weight of high-viscosity vinyl silicone oil to a vacuum kneader, start stirring, then add 10-20 parts of hydrophilic fumed silica and 10-20 parts of hydrophobic fumed silica, mix well, then add 10-20 parts of low-viscosity vinyl silicone oil, heat to 150-160℃ and then vacuum, maintain the vacuum degree at -0.095 MPa, and remove the vacuum for 1-2 hours to obtain the base adhesive; Step S2: Divide the base adhesive obtained in step S1 into two equal parts by weight. Add 0.5-1 part of platinum catalyst to one part, mix well to obtain component A, and add 5-10 parts of hydrogen-containing silicone oil and 0.5-1 part of inhibitor to the other part, mix well to obtain component B. Step S3: Mix component A and component B obtained in step S2 at a weight ratio of 1:1 and place them in a vacuum mixer. Stir for 15-30 minutes under a vacuum of -0.095 MPa. Step 3: Demolding. Remove the silicone mold from the injection mold.

2. The method for manufacturing a silicone mold for texturing textures on a mobile phone back cover according to claim 1, characterized in that: The inhibitor is ethynylcyclohexanol.

3. The method for manufacturing a silicone mold for texturing on a mobile phone back cover according to claim 1, characterized in that: The high-viscosity vinyl silicone oil has a viscosity of 20,000 mPa·s, and the low-viscosity vinyl silicone oil has a viscosity of 10,000 mPa·s.

4. The method for manufacturing a silicone mold for texturing on a mobile phone back cover according to claim 1, characterized in that: The specific surface area of ​​the hydrophilic fumed silica is 200 m², and the specific surface area of ​​the hydrophobic fumed silica is 300 m².

5. A method for manufacturing a silicone mold for texturing on a mobile phone back cover according to claim 1, characterized in that: In step 2, the heating temperature is 80-180℃, the pressure inside the injection mold cavity is 380-480N, and the heating and pressurizing time is 380-600s.

6. A silicone mold for texturing on mobile phone back covers, characterized in that: It is prepared by the method of manufacturing a silicone mold for texturing the back cover of a mobile phone as described in any one of claims 1-5.

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