A mobile phone case and its production process

Abstract

The present invention relates to a mobile phone case, which comprises a case back plate part and a case side surround part connected as a whole. Inside the case back plate part, there is a back plate main body having the same material, pattern and performance as the mobile phone back cover. The back plate main body includes a transparent substrate, and a surface hardening layer and an adhesiveness-enhancing functional resin coating are sequentially coated on the outer surface of the transparent substrate. On the inner surface of the transparent substrate, a printed ink layer, a laser holographic image texture layer, an optical coating layer and a heat-resistant and high-temperature-resistant functional resin bottom coating are sequentially attached. The mobile phone case of the present invention forms various functional layers by coating or attaching ink materials and various resin materials on both sides of the substrate surface, and adopts the laser holographic image texture manufacturing technology to form a laser holographic image texture layer, so that the mobile phone case product of the present invention has an anti-counterfeiting function; at the same time, it can meet the performance standards of the mobile phone back shell, and compared with the performance standards of ordinary mobile phone cases, the performance standards of the mobile phone case of the present invention are improved several times.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile phone peripheral products, and particularly to a mobile phone case and its production process. Background Art

[0002] Due to its many powerful functions and super portability, the mobile phone has become an essential electronic product in people's daily lives. There are a wide variety of mobile phones on the market, with prices ranging from hundreds or thousands to tens of thousands. Moreover, the distribution and structure of internal components of mobile phones are becoming more and more precise, so the anti-seismic protection of mobile phones is particularly important. Therefore, people usually equip mobile phone cases to protect their mobile phones.

[0003] Existing mobile phone cases are generally integrally formed using plastic or resin materials. Some mobile phone cases will attach special patterns on the outer surface to show individuality and meet different consumers. Such mobile phone cases have a simple structure but low standards, the market is chaotic, and the quality is uneven. Consumers are likely to buy mobile phone cases with poor performance, which provide limited protection for mobile phones and cause losses to themselves. Moreover, this kind of case obscures the original mobile phone back cover, making it difficult to display the original appearance design of the mobile phone, with poor decorative effects and no anti-counterfeiting function. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of existing products and provide a mobile phone case and its production process.

[0005] The technical solution adopted by the present invention is: a mobile phone case, which includes a protective case back plate part and a protective case side wall part connected as a whole. Among them: inside the protective case back plate part, there is a back plate main body, and the back plate main body includes a transparent substrate. On the outer surface of the transparent substrate, a surface hardening layer and an adhesion-enhancing functional resin coating are sequentially coated. On the inner surface of the transparent substrate, a printing ink layer, a laser holographic image texture layer, an optical coating layer, and a heat-resistant and high-temperature-resistant functional resin bottom coating are sequentially attached. And around the back plate main body, a hot-melt resin layer that completely covers the back plate main body is formed by in-mold injection molding, and the hot-melt resin layer extends along the edge of the back plate main body towards the inner surface direction to form the protective case side wall part.

[0006] In the above mobile phone case, the transparent substrate is a printable PMMA / PC composite board or other high molecular resin boards.

[0007] In the above mobile phone case, the surface hardening layer is a UV hardening resin with a thickness ≤ 8μm and a hardness ≤ 6H.

[0008] In the above mobile phone case, the adhesion-enhancing functional resin coating is one or more coating layers formed by one or more of acrylic acid, polyurethane, or water-based polyester resins, and its thickness ≤ 20μm.

[0009] In the above mobile phone case, the printed ink layer is an ink layer formed by screen printing, offset printing, digital printing or gravure printing, and the thickness of the ink layer is ≤ 100 μm. The ink type is one or more of functional ink, transparent ink, transparent and covering color ink, laser ink, and various types of anti-counterfeiting ink and functional decorative ink.

[0010] In the above mobile phone case, the material of the laser holographic image texture layer is UV resin. After being cured by ultraviolet light source irradiation, the resin material is transferred through a transfer process to form a laser holographic image texture layer. The thickness of the laser holographic image texture layer is ≤ 2.6 μm, and the depth of the laser holographic image texture (grating) is ≤ 1 μm.

[0011] In the above mobile phone case, the optical coating layer has two types: transparent and reflective, and its thickness is in the order of hundreds of angstroms;

[0012] In the above mobile phone case, the heat-resistant and high-temperature-resistant functional resin bottom coating is one to multiple coating layers of acrylic, polyurethane or water-based polyester resin, with a thickness ≤ 30 μm and a coating dry weight of 0.05 - 3 g / m 2 。

[0013] In the above mobile phone case, the hot-melt resin layer is a hot-melt adhesive resin mainly composed of one or several mixtures of TPU, ABS, PP, and PE, and the injection temperature is 200°C - 280°C.

[0014] The present invention also provides a production method for the above mobile phone case, which includes the following steps:

[0015] Step (1), coat one or more printed inks on the inner surface of the transparent substrate to form a printed ink layer;

[0016] Step (2), transfer resin material on the outer surface of the printed ink layer through a transfer process to form a laser holographic image texture layer;

[0017] Step (3), attach a transparent brightening optical coating on the surface of the laser holographic image texture layer obtained in step (2) to form an optical coating layer;

[0018] Step (4), coat heat-resistant and high-temperature-resistant resin on the surface of the optical coating layer to form a heat-resistant and high-temperature-resistant resin bottom coating;

[0019] Step (5), coat UV resin on the outer surface of the transparent substrate to form a surface hardening layer;

[0020] Step (6), coat a tackifying functional resin on the outer surface of the surface hardening layer to form a tackifying functional resin layer;

[0021] After steps (i) - (vi), a backplane body is formed on the transparent substrate, with a printing ink layer, a laser holographic image texture layer, an optical coating layer, a heat-resistant and high-temperature-resistant functional resin primer layer successively attached to the inner surface, and a surface hardening layer and an adhesion-enhancing functional resin coating layer successively coated on the outer surface.

[0022] Step (vii): Perform the IMD process on the backplane body, that is, place the backplane body into a mold for in-mold injection molding of a protective sleeve. The backplane body is coated with a thermoplastic resin to form a protective sleeve backplane part, and the thermoplastic resin extends along the edge of the backplane body towards the inner surface direction to form a protective sleeve side surround part.

[0023] In the above production method, after completing step (iv) and before step (v), high-pressure molding is also carried out to slightly bend the edge of the composite board to fit the mobile phone back shell, and then a fine carving process is carried out for trimming and precise sizing.

[0024] The mobile phone protective case of the present invention uses a board such as an acrylic board or a similar material as the substrate, forms various functional layers by coating or attaching ink materials and various resin materials on both sides of the substrate, and adopts a laser holographic image texture production technology to form a laser holographic image texture layer, so that the mobile phone protective case product of the present invention has an anti-counterfeiting function, and its aesthetic decoration effect is incomparable to that of ordinary mobile phone protective cases; at the same time, the anti-drop and anti-seismic performance of the mobile phone protective case of the present invention is further improved, and it can reach the performance standard of the mobile phone back shell. Compared with the performance standard of ordinary mobile phone protective cases, the performance standard of the mobile phone protective case of the present invention is improved several times. Description of the Drawings

[0025] Figure 1 is an overall cross-sectional schematic diagram of the mobile phone protective case of the present invention;

[0026] Figure 2 is a partial hierarchical structure schematic diagram of the mobile phone protective case of the present invention. Detailed Embodiments

[0027] The present invention will be further described below in conjunction with specific embodiments and the drawings.

[0028] Such as Figure 1 、 Figure 2As shown in the figure, the present invention relates to a mobile phone case, which includes a case back plate portion 1 and a case side wall portion 2 connected as a whole. Among them: inside the case back plate portion 1, there is a back plate main body 3, and the back plate main body 3 includes a transparent substrate 31. On the outer surface of the transparent substrate 31, a surface hardening layer 32 and an adhesiveness-enhancing functional resin coating 33 are sequentially coated. On the inner surface of the transparent substrate 31, a printing ink layer 34, a laser holographic image texture layer 35, an optical coating layer 36, and a heat-resistant and high-temperature-resistant functional resin bottom coating 37 are sequentially attached. And around the back plate main body 3, a hot-melt resin layer 38 covering the back plate main body 3 is formed by in-mold injection molding, and the hot-melt resin layer 38 extends along the edge of the back plate main body 3 towards its inner surface to form the case side wall portion 2.

[0029] In the above-mentioned mobile phone case, the transparent substrate 31 is a printable PMMA / PC composite board or other high molecular resin boards.

[0030] In the above-mentioned mobile phone case, the surface hardening layer 32 is a UV hardening resin with a thickness ≤ 8μm and a hardness ≤ 6H.

[0031] In the above-mentioned mobile phone case, the adhesiveness-enhancing functional resin coating 33 is one or more coating layers formed by one or more of acrylic, polyurethane, or water-based polyester resins, and its thickness ≤ 20μm.

[0032] In the above-mentioned mobile phone case, the printing ink layer 34 is an ink layer formed by screen printing, offset printing, digital printing, or gravure printing, and the thickness of the ink layer ≤ 100μm. The ink type is one or more of functional ink, transparent ink, transparent and covering color ink, laser ink, and various types of anti-counterfeiting ink and functional decorative ink.

[0033] In the above-mentioned mobile phone case, the material of the laser holographic image texture layer 35 is UV resin. After being cured by ultraviolet light source irradiation, a laser holographic image texture layer is formed by transferring resin materials through a transfer process. The thickness of the laser holographic image texture layer 35 ≤ 2.6μm, and the depth of the laser holographic image texture (grating) ≤ 1μm. The transfer process can be a C² process, a water transfer process, or other known transfer processes.

[0034] In the above-mentioned mobile phone case, the optical coating layer 36 is of two types: transparent optical coating and reflection, and its thickness is in the order of angstroms;

[0035] In the above-mentioned mobile phone case, the heat-insulating and temperature-resistant functional resin coating 37 (bottom coating) is one to multiple coating layers of acrylic, polyurethane, or water-based polyester resins, with a thickness ≤ 30μm and a coating dry weight of 0.05 - 3g / m 2 。

[0036] In the above mobile phone case, the resin layer for IMD in-mold injection is a hot-melt adhesive resin mainly composed of one or several mixtures of TPU, ABS, PP, and PE, and the injection temperature is 200-280 °C.

[0037] The present invention also provides a production method for the above mobile phone case, and this method includes the following steps:

[0038] Step (1), coat one or more printing inks on the inner surface of the transparent substrate 31 to form a printing ink layer 34;

[0039] Step (2), transfer a resin material on the outer surface of the printing ink layer 34 through a transfer process to form a laser holographic image texture layer 35;

[0040] Step (3), attach a transparent brightening optical coating on the surface of the laser holographic image texture layer 36 obtained in step (2) to form an optical coating layer 35;

[0041] Step (4), coat a heat-resistant and high-temperature-resistant resin on the surface of the optical coating layer to form a heat-resistant and high-temperature-resistant resin bottom layer 36;

[0042] Step (5), coat a UV resin on the outer surface of the transparent substrate 31 to form a surface hardening layer 32;

[0043] Step (6), coat a tackifying functional resin on the outer surface of the surface hardening layer 32 to form a tackifying functional resin layer 33;

[0044] After steps (1)-(6), the transparent substrate 31 forms a backplane main body 3 with a printing ink layer 34, a laser holographic image texture layer 35, an optical coating layer 36, a heat-resistant and high-temperature-resistant functional resin bottom layer 37 attached to the inner surface in sequence, and a surface hardening layer 31 and a tackifying functional resin coating layer 32 coated on the outer surface in sequence;

[0045] Step (7), perform the IMD process on the backplane main body 3, that is, place the backplane main body 3 into a mold for in-mold injection molding of the case. The backplane main body 3 is coated with a hot-melt resin to form a case backplane part 1, and the hot-melt resin extends along the edge of the backplane main body 3 towards the inner surface direction to form a case side surround part 2.

[0046] In the above production method, after completing step (4) and before step (5), high-pressure molding is also performed to make the edge of the composite board slightly bent to fit the mobile phone back shell, and then a fine carving process is carried out for trimming and precise sizing. Specific Example 1:

[0048] 1. Manufacturing process: PMMA / PC composite board → Printing metallic ink, color transparent ink, and color covering ink → Using C² process to transfer resin to generate a laser holographic image texture layer → Conducting optical coating with two different reflectivities → Performing printing and coating of various functions according to process requirements → Coating a heat-resistant and high-temperature-resistant functional base coat → High-pressure forming and precision engraving → Performing UV resin coating to form a surface hardening layer → Coating a tackifying functional coating on the surface (upper surface) of the UV-cured resin layer → Performing IMD processing. Specifically, it includes the following steps:

[0049] Step 1: Print transparent ink and covering color ink on the inner surface of the PMMA / PC composite board;

[0050] Step 2: Use C² process to transfer resin to generate a laser holographic image texture layer, with the resin thickness of the image being 2.5 - 3.0 μm and the depth of the laser holographic image texture (grating) being ≤ 1 μm;

[0051] Step 3: Conduct optical coating with two different reflectivities on the laser holographic image texture obtained in Step 2;

[0052] Step 4: Sequentially print functional ink or coat functional resin;

[0053] Step 5: High-pressure forming and precision engraving;

[0054] Step 6: Use UV resin coating to form a surface hardening layer;

[0055] Step 7: Coat a tackifying functional coating on the surface (upper surface) of the UV-cured resin layer;

[0056] Step 8: Perform IMD (8) processing.

[0057] IMD processing: In this embodiment, TPU hot melt adhesive pellets with a specific melt index are dried and then injected into an in-mold injection machine. At a melting temperature of 250 °C, after in-mold injection processing, it is compounded with the PMMA / PC composite board. A protective film is pasted to form a mobile phone sheath including all the processes of the present invention.

[0058] During the in-mold injection processing, the cavity thickness can be adjusted according to actual needs, thereby adjusting the overall thickness of the protective cover.

[0059] The function of the tackifying functional coating is to ensure the composite strength between the PMMA / PC composite board and the TPU resin injection molding;

[0060] The functions of the heat-insulating and high-temperature resistant coating are as follows: protecting the laser holographic texture and the appearance of the ink unchanged. The chemical components of the tackifying and heat-insulating and high-temperature resistant coatings are acrylic acid, polyurethane, waterborne polyester resin and their mixed coatings. The specific functions are as follows: Coating the tackifying functional coating ensures that during the IMD process, on the surface of the hardened resin with a common smooth surface wetting tension ≤ 0.28, after being compounded with ABS resin, the peel strength is qualified and the mobile phone sheath product does not crack; the heat-insulating and high-temperature resistant coating protects the ink and the laser holographic image texture from discoloring during the high-temperature process of IMD.

[0061] In this embodiment, the resin of the tackifying layer is a waterborne primer: made by drying an aqueous solution of polyethyleneimine. Generally, the dry coating weight is 0.04 - 0.14 g / m2, and the solid content is 0.7% - 5.5%; the dry weight of the primer is 0.14 g / m2, and the thickness is 0.05 microns. Specific embodiment

[0062] 1. Production process: PMMA / PC composite board → printing pearlescent ink, transparent color printing ink and covering ink → using water transfer printing process to transfer resin to generate a laser holographic image texture layer → transparent brightening optical coating → performing various printing and coating according to process requirements → coating a heat-insulating and high-temperature resistant functional primer → high-pressure forming and fine carving → performing UV resin coating to form a surface hardening layer → coating a tackifying functional coating on the surface (upper surface) of the UV hardened resin layer → performing IMD processing. Specifically, it includes the following steps:

[0063] Step 1: Print pearlescent ink, transparent color ink, and covering ink on the inner surface of the PMMA / PC composite board.

[0064] Step 2: Use the water transfer printing process to transfer resin to generate a laser holographic image texture layer, the thickness of the resin for the image is 2.6 μm, and the depth of the laser holographic image texture (grating) ≤ 1 μm.

[0065] Step 3: Perform a transparent brightening optical coating on the laser holographic image texture obtained in Step 2.

[0066] Step 4: Print functional ink or coat functional resin in sequence.

[0067] Step 5: High-pressure forming and fine carving. High-pressure forming hot-presses the edge of the composite board into a slightly curved shape to match the curved shape of the edge of the mobile phone back shell. Fine carving is to perform edge trimming to make the size of the product accurate.

[0068] Step 6: Use UV resin coating to form a surface hardening layer.

[0069] Step 7: Coat a tackifying functional coating on the surface (upper surface) of the UV hardened resin layer.

[0070] Step 8: Perform IMD processing.

[0071] Function of the tackifying functional coating:

[0072] Ensure that during the IMD process, the hardened resin surface with a smooth wetting tension ≤ 0.28 can be compounded with the ABS resin, and the peeling force is qualified, and the mobile phone sheath product does not crack.

[0073] Function of the high-temperature resistant functional coating:

[0074] Protect the ink layer, laser holographic texture layer, plating layer and coating, and can withstand the injection molding temperature of the molten state ABS resin at 260 °C during the IMD process without changes in appearance, physical and chemical properties.

[0075] IMD processing: In this example, ABS hot melt adhesive pellets with a specific melt index are dried and then injected into an in-mold injection molding machine. At a melting temperature of 200 - 260 °C, after the in-mold injection molding process, they are compounded with a PMMA / PC composite board, and a protective film is pasted to form a mobile phone sheath containing the process of the present invention.

[0076] During the in-mold injection molding process, the thickness of the protective cover can be controlled by adjusting the cavity thickness according to actual needs.

[0077] The tackifying functional coating and the heat-resistant and high-temperature resistant functional coating used in this embodiment are solvent-based resins, which is a process requirement because the IMD processing temperature of ABS is higher than that of TPU. The chemical components of both are polyurethane, polyester resin and their mixed coatings, and the general coating dry weight is 1.2 - 1.8 g / m2, and the thickness ≤ 2 microns.

[0078] The present invention utilizes the principles of optical refraction and reflection generated by functional inks and coatings to reflect color effects; utilizes UV curing, texture transfer, precision coating, and IMD processes to achieve the functional effects of mobile phone protective case products; generates laser holographic image effects based on the principles of optical interference and diffraction, and has a design with laser holographic anti-counterfeiting effects to identify product authenticity and protect brand patterns;

[0079] Generate a laser holographic image texture layer through the UV transfer resin of the C² process, and the optical coating layer increases the reflection effect and brightness. After high-pressure molding and precision carving, it has a surface hardening layer of UV-cured resin, a tackifying functional coating and a heat-resistant and temperature-resistant functional coating, and uses hot melt adhesive resins such as TPU for IMD process processing.

[0080] In summary, the mobile phone case of the present invention uses a board made of acrylic board or similar materials as the substrate, forms various functional layers by coating or attaching ink materials and various resin materials on both surfaces of the substrate, and adopts the laser holographic image texture manufacturing technology to form a laser holographic image texture layer, so that the mobile phone case product of the present invention has an anti-counterfeiting function, and its beautiful decorative effect is incomparable to that of ordinary mobile phone cases; at the same time, the anti-drop and anti-seismic performance of the mobile phone case of the present invention is further improved, and it can meet the performance standard of the mobile phone back shell. Compared with the performance standard of ordinary mobile phone cases, the performance standard of the mobile phone case of the present invention is improved several times.

Claims

1. A mobile phone case, which comprises a case back plate part and a case side surround part connected as a whole, and is characterized in that: Inside the back plate part of the protective case, there is a back plate main body. The back plate main body includes a transparent substrate. On the outer surface of the transparent substrate, a surface hardening layer and an adhesion-enhancing functional resin coating are successively coated. On the inner surface of the transparent substrate, a printed ink layer, a laser holographic image texture layer, an optical coating layer, and a heat-resistant and high-temperature-resistant functional resin bottom coating are successively attached. And around the back plate main body, a hot-melt resin layer that completely covers the back plate main body is formed by in-mold injection molding. The hot-melt resin layer extends along the edge of the back plate main body towards the inner surface direction to form the side surrounding part of the protective case.

2. The mobile phone case according to claim 1, characterized in that: The transparent substrate is a printable PMMA / PC composite board or other polymer resin boards.

3. The mobile phone case according to claim 1, wherein: The surface hardening layer is a UV-cured resin with a thickness ≤ 8μm and a hardness ≤ 6H.

4. The mobile phone case according to claim 1, characterized in that: The adhesion-enhancing functional resin coating is one or more coating layers formed by one or more of acrylic, polyurethane, or water-based polyester resins, and its thickness ≤ 20μm.

5. The mobile phone case according to claim 1, characterized in that: The printed ink layer is an ink layer formed by screen printing, offset printing, digital printing, or gravure printing. And the thickness of the ink layer ≤ 100μm. The ink type is one or more of functional ink, transparent ink, transparent and covering color ink, laser ink, and various types of anti-counterfeiting ink and functional decorative ink.

6. The mobile phone case according to claim 1, wherein: The material of the laser holographic image texture layer is UV resin. After being cured by ultraviolet light source irradiation, a laser holographic image texture layer is formed by transferring resin materials through a transfer process. The thickness of the laser holographic image texture layer is ≤ 2.6μm, and the depth of the laser holographic image texture (grating) is ≤ 1μm.

7. The mobile phone case according to claim 1, characterized in that: The optical coating layer has two types: transparent and reflective, and its thickness is in the order of angstroms.

8. The mobile phone case according to claim 1, wherein: The heat-resistant and high-temperature-resistant functional resin primer coat is one to multiple coating layers of acrylic, polyurethane or water-based polyester resin, with a thickness ≤ 30 μm and a coating dry weight of 0.05 - 3 g / m 2 .

9. The mobile phone case according to claim 1, characterized in that: The hot-melt resin layer is a hot-melt adhesive resin mainly composed of one or several mixtures of TPU, ABS, PP, and PE, and the injection temperature is 200°C - 280°C.

10. The production method of the mobile phone case according to any one of claims 1-9, characterized in that: This method includes the following steps: Step (1), coat one or more printed inks on the inner surface of the transparent substrate to form a printed ink layer; Step (2), transfer resin materials on the outer surface of the printed ink layer through a transfer process to form a laser holographic image texture layer; Step (3), attach a transparent brightening optical coating on the surface of the laser holographic image texture layer obtained in step (2) to form an optical coating layer; Step (4), coat a heat-resistant and high-temperature-resistant resin on the surface of the optical coating layer to form a heat-resistant and high-temperature-resistant resin bottom coating; Step (5), coat UV resin on the outer surface of the transparent substrate to form a surface hardening layer; Step (6), coat an adhesion-enhancing functional resin on the outer surface of the surface hardening layer to form an adhesion-enhancing functional resin layer; After steps (1) - (6), the transparent substrate forms a back plate main body with a printed ink layer, a laser holographic image texture layer, an optical coating layer, a heat-resistant and high-temperature-resistant functional resin bottom coating successively attached to the inner surface, and a surface hardening layer and an adhesion-enhancing functional resin coating successively coated on the outer surface; Step (7), perform IMD process on the back plate main body, that is, place the back plate main body into a mold for in-mold injection molding to form a protective case. The back plate main body is covered by a hot-melt resin to form the back plate part of the protective case, and the hot-melt resin extends along the edge of the back plate main body towards the inner surface direction to form the side surrounding part of the protective case.

11. The production method of the mobile phone case according to claim 10, characterized in that: After completing step (iv) and before step (v), high-pressure forming is also carried out to slightly bend the edges of the composite sheet to fit the mobile phone back cover, and then a fine carving process is carried out for edge trimming and precise sizing.

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