Processing method of novel hidden light-transmitting plastic automobile airbag cover ornament

Abstract

The invention discloses a processing method of a novel hidden light-transmitting plastic automobile airbag cover ornament, and particularly relates to the field of automobile interior ornament processing, the processing method comprises the following steps: S1, selecting a semi-cured transparent PC film, the thickness of the semi-cured transparent PC film is 0.1 mm-0. 25mm, a coating is preset on the surface of the semi-cured transparent PC film, and the coating is an acrylate wear-resistant coating; s2, a semi-transparent layer is printed on the non-coating surface of the semi-cured transparent PC film through a silk-screen printing technology, the mesh number of a printing screen is 200-300 meshes, the printing speed is 1-3 m / min, and pre-curing is conducted for 10-15 min in the environment with the temperature ranging from 60 DEG C to 80 DEG C after printing; and S3, printing a hollowed-out shielding layer on the surface of the printed semi-transparent layer by adopting a silk-screen printing process. The technical bottleneck that hidden light transmission cannot be achieved through a traditional technology is solved, the requirements for individuation and science and technology of automotive trim are met, 3-4 independent procedures are reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of automotive interior parts processing, and more specifically, to a processing method for a novel concealed translucent plastic automotive airbag cover trim. Background Technology

[0002] As a key component of automotive interiors, airbag cover trim not only needs to meet basic safety requirements, but its aesthetic appeal and technological feel have also become core indicators for improving the overall quality of the vehicle interior. With consumers' ever-increasing demands for personalized and intelligent automotive interiors, airbag cover trim with a concealed light-transmitting effect, due to its ability to blend discreetly in the absence of light and precisely reflect light when illuminated, is gradually becoming a hot research topic in the industry.

[0003] In existing technologies, the appearance molding of automotive airbag cover trim parts mainly relies on two traditional processes: one is the "spraying + inlaying" process, which involves first spraying the surface of the injection-molded plastic airbag cover, and then inlaying the solid trim parts with patterns, text, or logos onto the surface of the cover; the other is the "covering + inlaying" process, which involves covering the airbag cover base with materials such as leather or fabric, and then inlaying the solid trim parts. However, both processes have significant drawbacks: on the one hand, the inlaid solid trim parts cannot achieve the function of lighting, making it difficult to meet consumers' demand for a technological interior, and the inlay structure is prone to problems such as gaps and falling off, affecting the integrity and service life of the trim parts; on the other hand, the process flow is cumbersome, requiring multiple independent processes such as injection molding, spraying / covering, and inlaying, which not only results in low production efficiency, but also the positioning errors between processes can easily lead to a decrease in decorative precision, significantly increasing manufacturing costs.

[0004] To address the aforementioned problems, a technical solution is provided. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention provide a new method for processing a hidden translucent plastic automotive airbag cover trim, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A processing method for a novel concealed, translucent plastic automotive airbag cover trim includes the following steps: Step S1: Select a semi-cured transparent PC film with a thickness of 0.1mm-0.25mm. The surface of the semi-cured transparent PC film is pre-coated with a coating, which is an acrylic wear-resistant coating. Step S2: A semi-transparent layer is printed on the uncoated surface of the semi-cured transparent PC film using screen printing technology. The screen mesh count is 200-300 mesh, the printing speed is 1-3 m / min, and the film is pre-cured at 60-80℃ for 10-15 min after printing. Step S3: A perforated masking layer is printed on the surface of the printed semi-transparent layer using screen printing technology. The pattern of the perforated masking layer is consistent with the text, logo or pattern to be presented. The screen mesh count is 300-400 mesh. After printing, it is cured at 80-100℃ for 20-25 minutes. Step S4: Using screen printing, an adhesive layer is printed on the surface of the printed cutout masking layer. The screen mesh number is 250-350. After printing, the film is cured at 70-90℃ for 15-20 minutes to obtain a composite film. Step S5: Place the composite film into the cavity of the injection mold, with the coating of the semi-cured transparent PC film facing the outside of the mold cavity. Use an injection molding machine to inject the molten injection material into the mold. The injection temperature is 180-220℃, the injection pressure is 80-120MPa, and the holding time is 10-15s. After cooling and molding, open the mold and remove the injection molded part. After the injection molded part cools to room temperature, assemble the light-emitting module on the back of the injection molded part at the position corresponding to the hollowed-out shielding layer, and finally obtain the hidden light-transmitting plastic car airbag cover trim.

[0007] In a preferred embodiment, in step S2, the semi-transparent layer is printed with modified polyurethane ink, which contains 5-8% by mass of titanium dioxide opacifier, the thickness of the semi-transparent layer is 8-12 μm, and the light transmittance of the semi-transparent layer is 10%-20%.

[0008] Modified polyurethane resin, as the main film-forming substance, accounts for 45%-60%, providing flexibility, weather resistance, and interfacial compatibility with PC film and TPO / PP injection molding materials for the ink layer; functional light-shielding filler rutile titanium dioxide accounts for 5%-8%, precisely controlling the light transmittance of the semi-transparent layer to 10%-20%, achieving a hidden light transmission effect; ester and ketone mixed solvents account for 15%-25%, ensuring printing leveling and rapid film formation in the pre-curing stage, with no residue after curing; the additive system (including dispersant, leveling agent, and adhesion promoter) accounts for 1%-5%, where the dispersant ensures uniform dispersion of titanium dioxide, the leveling agent ensures uniform coating thickness (8-12μm), and the adhesion promoter enhances the adhesion strength to the PC film; and polyisocyanate crosslinking curing agents account for 1%-3%.

[0009] In a preferred embodiment, in step S3, the perforated masking layer is printed with epoxy-modified acrylic ink, which contains 10-15% carbon black opacifier by mass, the thickness of the perforated masking layer is 10-15 μm, and the light transmittance of the perforated masking layer is ≤0.5%.

[0010] Epoxy-modified acrylic resin, comprising 40%-55% of the main film-forming substance, combines the rigidity and chemical resistance of epoxy resin with the flexibility and printability of acrylic resin. Under curing conditions of 80-100℃, it forms a dense coating and achieves good interfacial adhesion with the semi-transparent layer and subsequent adhesive layer. High-opacity functional filler carbon black accounts for 10%-15%, ester and alcohol ether mixed solvents account for 20%-30%, auxiliary agent system (including dispersant, defoamer, and adhesion promoter) accounts for 2%-6%, and amine or acid anhydride curing agent accounts for 3%-8%. It undergoes a cross-linking reaction with epoxy-modified acrylic resin to form a three-dimensional network structure.

[0011] In a preferred embodiment, in step S4, the adhesive layer is printed with polyolefin-grafted maleic anhydride ink, the grafting rate of the polyolefin-grafted maleic anhydride ink is 1.5-2.5%, and the thickness of the adhesive layer is 12-18 μm.

[0012] The maleic anhydride groups grafted onto the polyolefin molecular structure form strong chemical bonds and physical entanglements with the hydroxyl groups on the surface of the semi-cured PC film and the non-polar molecules of the TPO / PP material used in injection molding. This significantly improves the adhesion strength between the composite film and the injection molding substrate, preventing film delamination during the high temperature and high pressure process of in-mold injection molding, and ensuring the structural stability of the trim parts under harsh conditions such as high and low temperature cycling and humid heat aging. A grafting rate of 1.5-2.5% is the performance balance point. If the grafting rate is too low, there will be insufficient polar groups, and the adhesion strength will not meet the requirements. If the grafting rate is too high, the ink flexibility will decrease, and the coating will be prone to brittleness. The thickness design of 12-18μm ensures sufficient bonding contact area without causing problems such as poor printing leveling and incomplete curing due to excessive coating thickness. It is suitable for the high precision requirements of screen printing process, and finally achieves a firm bond between the composite film and the injection molded part, meeting the reliability requirements of long-term use of automotive interior parts.

[0013] In a preferred embodiment, in step S5, the injection molding material is TPO material or PP material. When TPO material is used, its melt index is 8-12 g / min, and when PP material is used, its melt index is 10-15 g / min.

[0014] TPO and PP materials within the melt flow index range possess excellent molding stability. They can smoothly fill the mold cavity at injection temperatures of 180-220℃ and injection pressures of 80-120MPa. The flexibility of TPO and the rigidity of PP materials are suitable for the performance and cost requirements of airbag cover trim parts in different vehicle models. Both have excellent material compatibility with polyolefin-grafted maleic anhydride adhesive layers. They can enhance the adhesion strength to the composite film through physical entanglement and chemical bonding between molecules, preventing film layer delamination during subsequent use.

[0015] In a preferred embodiment, in step S5, the surface roughness Ra of the injection mold cavity is ≤0.8μm, the injection mold temperature is controlled at 40-60℃, and before the composite film is placed into the cavity, its adhesive layer surface is subjected to plasma treatment with a plasma treatment power of 300-500W and a treatment time of 3-5s.

[0016] A cavity surface roughness Ra≤0.8μm can reduce the flow resistance of molten TPO / PP material, allowing the melt to fill the cavity uniformly. Controlling the mold temperature within the range of 40-60℃ can prevent premature softening and deformation of the film due to excessively high mold temperature, or internal stress defects caused by excessively low temperature leading to rapid cooling of the injection molded part. Furthermore, plasma treatment of the adhesive layer surface of the composite film with 300-500W power for 3-5s removes oil, impurities, and other contaminants from the adhesive layer surface through the etching and activation effects of plasma. At the same time, it increases the surface roughness and the number of active groups, significantly improving the interfacial bonding strength between the adhesive layer and the injection molding material, effectively preventing film delamination after in-mold injection molding.

[0017] In a preferred embodiment, in step S5, the light-emitting module includes a PCB substrate, LED beads, and a light guide plate. The LED beads are soldered onto the PCB substrate, and the light emission wavelength of the LED beads is 450-650nm, with a power of 0.5-1W. The light guide plate is made of PMMA material, with a thickness of 2-4mm. The light-incident surface of the light guide plate corresponds to the LED beads, and the light-emitting surface is attached to the hollowed-out shielding layer area on the back of the injection molded part.

[0018] LED beads with a light emission wavelength of 450-650nm cover the full visible light spectrum, matching the light transmission display requirements of different color patterns and logos. The structure of the light-incident surface corresponding to the LED beads and the light-emitting surface precisely fitting the hollowed-out shielding layer guides the light to focus on the preset pattern area, improving the clarity of the pattern display. It is fully adapted to the requirements of hidden light-transmitting plastic car airbag cover trim parts that are hidden when there is no light source and clearly visible when there is a light source, meeting the miniaturization requirements of automotive interior parts.

[0019] In a preferred embodiment, in step S5, the light-emitting module and the injection molded part are assembled by snap-fit ​​connection and fixed with hot melt adhesive, wherein the hot melt adhesive is EVA type hot melt adhesive with a melting temperature of 80-100℃.

[0020] The technical effects and advantages of the processing method of the novel concealed translucent plastic automotive airbag cover trim of the present invention are as follows: 1. Through the synergistic design of the semi-transparent layer and the hollowed-out shielding layer, combined with precise material parameter control, the 10%-20% light transmittance of the semi-transparent layer and the ≤0.5% light blocking rate of the hollowed-out shielding layer complement each other when the light source is not turned on, so the pattern on the back is completely hidden, only showing natural color and texture; when the light source is turned on, the light is precisely transmitted to the hollowed-out shielding layer area through the light guide plate. Combined with the uniform light transmission characteristics of the semi-transparent layer, the pattern clarity can reach level 5, which solves the technical bottleneck of traditional processes that cannot achieve hidden light transmission, and meets the needs of personalized and technological car interiors; 2. The semi-transparent layer, the perforated shielding layer, and the adhesive layer are integrated onto the PC film through continuous screen printing, and then molded together with the injection-molded substrate in one step. Compared with the traditional "injection molding + spraying / coating + inlay" process, this reduces 3-4 independent processes, improves production efficiency, and the use of screen printing technology for each coating ensures high pattern positioning accuracy, avoids assembly errors of the inlay process, reduces scrap rate, and significantly reduces manufacturing costs.

[0021] 3. Through multiple structural and process optimizations, the stability of the trim is ensured. The adhesive layer uses polyolefin-grafted maleic anhydride ink with a grafting rate of 1.5-2.5%, forming a strong chemical bond with the PC film and TPO / PP matrix. Combined with plasma treatment, the interfacial adhesion strength is improved, and the peel strength retention rate reaches up to 95% after 500 hours of damp heat aging. The semi-transparent layer and the hollowed-out shielding layer use modified polyurethane and epoxy-modified acrylic resin systems, respectively. After cross-linking and curing, they form a dense coating. Combined with the acrylic wear-resistant coating on the surface of the PC film, the trim has excellent high and low temperature resistance and wear resistance. The light-emitting module is fixed with clips and EVA hot melt adhesive. The overall performance meets the stringent environmental testing requirements of automotive interior parts, and the service life is improved. Attached Figure Description

[0022] Figure 1 This is a schematic flowchart illustrating the processing method of a novel concealed translucent plastic automotive airbag cover trim for this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only 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.

[0024] Example 1 Figure 1 This invention discloses a processing method for a novel concealed, translucent plastic automotive airbag cover trim, specifically including the following steps: Step S1: Select a semi-cured transparent PC film with a thickness of 0.1 mm. The surface of the semi-cured transparent PC film has a pre-coated layer, which is an acrylic wear-resistant coating. Step S2: A semi-transparent layer is printed on the uncoated surface of the semi-cured transparent PC film using screen printing technology. The screen mesh count is 200 mesh, the printing speed is 1m / min, and the film is pre-cured at 60℃ for 10min after printing. Step S3: A cutout masking layer is printed on the surface of the printed semi-transparent layer using screen printing technology. The pattern of the cutout masking layer is consistent with the text, logo or pattern to be presented. The screen mesh count is 300 mesh. After printing, it is cured at 80℃ for 20 minutes. Step S4: Using screen printing, an adhesive layer is printed on the surface of the printed cutout masking layer. The screen mesh number is 250. After printing, the film is cured at 70°C for 15 minutes to obtain a composite film. Step S5: Place the composite film into the cavity of the injection mold, with the coating of the semi-cured transparent PC film facing the outside of the mold cavity. Use an injection molding machine to inject the molten injection material into the mold. The injection temperature is 180℃, the injection pressure is 80MPa, and the holding time is 10s. After cooling and molding, open the mold and remove the injection molded part. After the injection molded part cools to room temperature, assemble the light-emitting module on the back of the injection molded part at the position corresponding to the hollowed-out shielding layer, and finally obtain the hidden light-transmitting plastic car airbag cover trim.

[0025] In step S2, the semi-transparent layer is printed with modified polyurethane ink, which contains 5% by mass of titanium dioxide opacifier. The thickness of the semi-transparent layer is 8μm, and the light transmittance of the semi-transparent layer is 10%.

[0026] In step S3, the perforated masking layer is printed with epoxy-modified acrylic ink, which contains 10% carbon black opacifier by mass. The thickness of the perforated masking layer is 10μm, and the light transmittance of the perforated masking layer is ≤0.5%.

[0027] In step S4, the adhesive layer is printed using polyolefin-grafted maleic anhydride ink with a grafting rate of 1.5% and a thickness of 12 μm.

[0028] In step S5, the injection molding material is either TPO or PP. When using TPO, its melt index is 8 g / min, and when using PP, its melt index is 10 g / min.

[0029] In step S5, the surface roughness Ra of the injection mold cavity is ≤0.8μm, the injection mold temperature is controlled at 40℃, and before the composite film is placed into the cavity, its adhesive layer surface is subjected to plasma treatment with a plasma treatment power of 300W and a treatment time of 3s.

[0030] In step S5, the light-emitting module includes a PCB substrate, LED beads, and a light guide plate. The LED beads are soldered onto the PCB substrate, and the light emission wavelength of the LED beads is 450nm and the power is 0.5W. The light guide plate is made of PMMA material, and the thickness of the light guide plate is 2mm. The light-incident surface of the light guide plate corresponds to the LED beads, and the light-emitting surface is attached to the hollowed-out shielding layer area on the back of the injection molded part.

[0031] In step S5, the light-emitting module and the injection molded part are assembled by snap-fit ​​connection and hot melt adhesive. The hot melt adhesive is EVA type hot melt adhesive with a melting temperature of 80℃.

[0032] Example 2 Figure 1 This invention discloses a processing method for a novel concealed, translucent plastic automotive airbag cover trim, specifically including the following steps: Step S1: Select a semi-cured transparent PC film with a thickness of 0.2 mm. The surface of the semi-cured transparent PC film has a pre-coated layer, which is an acrylic wear-resistant coating. Step S2: A semi-transparent layer is printed on the uncoated surface of the semi-cured transparent PC film using screen printing technology. The screen mesh count is 250 mesh, the printing speed is 2m / min, and the film is pre-cured at 70℃ for 13min after printing. Step S3: A perforated masking layer is printed on the surface of the printed semi-transparent layer using screen printing technology. The pattern of the perforated masking layer is consistent with the text, logo or pattern to be presented. The screen mesh count is 350 mesh. After printing, it is cured at 90℃ for 23 minutes. Step S4: Using screen printing, an adhesive layer is printed on the surface of the printed cutout masking layer. The screen mesh number is 300. After printing, the film is cured at 80°C for 18 minutes to obtain a composite film. Step S5: Place the composite film into the cavity of the injection mold, with the coating of the semi-cured transparent PC film facing the outside of the mold cavity. Use an injection molding machine to inject the molten injection material into the mold. The injection temperature is 200℃, the injection pressure is 100MPa, and the holding time is 13s. After cooling and molding, open the mold and remove the injection molded part. After the injection molded part cools to room temperature, assemble the light-emitting module on the back of the injection molded part at the position corresponding to the hollowed-out shielding layer, and finally obtain the hidden light-transmitting plastic car airbag cover trim.

[0033] In step S2, the semi-transparent layer is printed with modified polyurethane ink, which contains 7% by mass of titanium dioxide opacifier. The thickness of the semi-transparent layer is 10 μm, and the light transmittance of the semi-transparent layer is 15%.

[0034] In step S3, the perforated masking layer is printed with epoxy-modified acrylic ink, which contains 12% carbon black opacifier by mass. The thickness of the perforated masking layer is 13μm, and the light transmittance of the perforated masking layer is ≤0.5%.

[0035] In step S4, the adhesive layer is printed using polyolefin-grafted maleic anhydride ink with a grafting rate of 2.0% and a thickness of 15 μm.

[0036] In step S5, the injection molding material is either TPO or PP. When using TPO, its melt index is 10 g / min, and when using PP, its melt index is 13 g / min.

[0037] In step S5, the surface roughness Ra of the injection mold cavity is ≤0.8μm, the injection mold temperature is controlled at 50℃, and before the composite film is placed into the cavity, its adhesive layer surface is subjected to plasma treatment with a plasma treatment power of 400W and a treatment time of 4s.

[0038] In step S5, the light-emitting module includes a PCB substrate, LED beads, and a light guide plate. The LED beads are soldered onto the PCB substrate, and the light emission wavelength of the LED beads is 550nm and the power is 0.8W. The light guide plate is made of PMMA material, and the thickness of the light guide plate is 3mm. The light-incident surface of the light guide plate corresponds to the LED beads, and the light-emitting surface is attached to the hollowed-out shielding layer area on the back of the injection molded part.

[0039] In step S5, the light-emitting module and the injection molded part are assembled by snap-fit ​​connection and fixed with hot melt adhesive. The hot melt adhesive is EVA type hot melt adhesive with a melting temperature of 90℃.

[0040] Example 3 Figure 1 This invention discloses a processing method for a novel concealed, translucent plastic automotive airbag cover trim, specifically including the following steps: Step S1: Select a semi-cured transparent PC film with a thickness of 0.25 mm. The surface of the semi-cured transparent PC film has a pre-coated layer, which is an acrylic wear-resistant coating. Step S2: A semi-transparent layer is printed on the uncoated surface of the semi-cured transparent PC film using screen printing technology. The screen mesh count is 300 mesh, the printing speed is 3m / min, and the film is pre-cured at 80℃ for 15min after printing. Step S3: A perforated masking layer is printed on the surface of the printed semi-transparent layer using screen printing technology. The pattern of the perforated masking layer is consistent with the text, logo or pattern to be presented. The screen mesh count is 400 mesh. After printing, it is cured at 100℃ for 25 minutes. Step S4: Using screen printing, an adhesive layer is printed on the surface of the printed cutout masking layer. The screen mesh number is 350. After printing, the film is cured at 90°C for 20 minutes to obtain a composite film. Step S5: Place the composite film into the cavity of the injection mold, with the coating of the semi-cured transparent PC film facing the outside of the mold cavity. Use an injection molding machine to inject the molten injection material into the mold. The injection temperature is 220℃, the injection pressure is 120MPa, and the holding time is 15s. After cooling and molding, open the mold and remove the injection molded part. After the injection molded part cools to room temperature, assemble the light-emitting module on the back of the injection molded part at the position corresponding to the hollowed-out shielding layer, and finally obtain the hidden light-transmitting plastic car airbag cover trim.

[0041] In step S2, the semi-transparent layer is printed with modified polyurethane ink, which contains 8% by mass of titanium dioxide opacifier. The thickness of the semi-transparent layer is 12μm, and the light transmittance of the semi-transparent layer is 20%.

[0042] In step S3, the perforated masking layer is printed with epoxy-modified acrylic ink, which contains 15% carbon black opacifier by mass. The thickness of the perforated masking layer is 15μm, and the light transmittance of the perforated masking layer is ≤0.5%.

[0043] In step S4, the adhesive layer is printed using polyolefin-grafted maleic anhydride ink with a grafting rate of 2.5% and a thickness of 18 μm.

[0044] In step S5, the injection molding material is either TPO or PP. When using TPO, its melt index is 12 g / min, and when using PP, its melt index is 15 g / min.

[0045] In step S5, the surface roughness Ra of the injection mold cavity is ≤0.8μm, the injection mold temperature is controlled at 60℃, and before the composite film is placed into the cavity, its adhesive layer surface is subjected to plasma treatment with a plasma treatment power of 500W and a treatment time of 5s.

[0046] In step S5, the light-emitting module includes a PCB substrate, LED beads and a light guide plate. The LED beads are soldered onto the PCB substrate, and the light emission wavelength of the LED beads is 650nm and the power is 1W. The light guide plate is made of PMMA material and has a thickness of 4mm. The light-incident surface of the light guide plate corresponds to the LED beads, and the light-emitting surface is attached to the hollowed-out shielding layer area on the back of the injection molded part.

[0047] In step S5, the light-emitting module and the injection molded part are assembled by snap-fit ​​connection and hot melt adhesive. The hot melt adhesive is EVA type hot melt adhesive with a melting temperature of 100℃.

[0048] The concealed translucent plastic car airbag cover trim parts prepared according to the methods of Examples 1-3 were first tested for their concealment and light transmission effects. The test method was to visually observe whether the back pattern was visible from the front when the light source was off; and then visually observe the pattern clarity (level 1-5, level 5 being the best) after the light source was turned on. The concealed translucent plastic car airbag cover trim parts obtained in Example 1 had no pattern visible, with a clarity level of 4; the concealed translucent plastic car airbag cover trim parts obtained in Example 2 had no pattern visible, with a clarity level of 5; and the concealed translucent plastic car airbag cover trim parts obtained in Example 3 had no pattern visible, with a clarity level of 4. Example 2 had the best parameter matching and the clearest pattern display.

[0049] The transmittance of the semi-transparent layer was tested using a transmittance tester. The transmittance of the semi-transparent layer in Example 1 was 10%; in Example 2, it was 15%; and in Example 3, it was 20%. The transmittance showed an increasing trend as the amount of titanium dioxide opacifier added decreased and the thickness of the semi-transparent layer increased.

[0050] Finally, the resistance to damp heat aging was tested. After testing at 40℃ and 90% relative humidity for 500 hours, the peel strength retention rate was as follows: 88% for the concealed translucent plastic car airbag cover trim obtained in Example 1, 95% for the concealed translucent plastic car airbag cover trim obtained in Example 2, and 90% for the concealed translucent plastic car airbag cover trim obtained in Example 3. The adhesive layer curing parameters of Example 2 were well matched, and the adhesion decay was minimal after damp heat aging.

[0051] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0052] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A processing method for a novel concealed, translucent plastic automotive airbag cover trim, characterized in that, Includes the following steps: Step S1: Select a semi-cured transparent PC film with a thickness of 0.1mm-0.25mm. The surface of the semi-cured transparent PC film is pre-coated with a coating, which is an acrylic wear-resistant coating. Step S2: A semi-transparent layer is printed on the uncoated surface of the semi-cured transparent PC film using screen printing technology. The screen mesh count is 200-300 mesh, the printing speed is 1-3 m / min, and the film is pre-cured at 60-80℃ for 10-15 min after printing. Step S3: Print a perforated masking layer on the surface of the printed semi-transparent layer using screen printing technology. The screen mesh count is 300-400 mesh. After printing, cure at 80-100℃ for 20-25 minutes. Step S4: Using screen printing, an adhesive layer is printed on the surface of the printed cutout masking layer. The screen mesh number is 250-350. After printing, the film is cured at 70-90℃ for 15-20 minutes to obtain a composite film. Step S5: Place the composite film into the cavity of the injection mold, with the coating of the semi-cured transparent PC film facing the outside of the mold cavity. Use an injection molding machine to inject the molten injection material into the mold. The injection temperature is 180-220℃, the injection pressure is 80-120MPa, and the holding time is 10-15s. After cooling and molding, open the mold and remove the injection molded part. After the injection molded part cools to room temperature, assemble the light-emitting module on the back of the injection molded part at the position corresponding to the hollowed-out shielding layer, and finally obtain the hidden light-transmitting plastic car airbag cover trim.

2. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 1, characterized in that: In step S2, the semi-transparent layer is printed with modified polyurethane ink, which contains 5-8% by mass of titanium dioxide opacifier. The thickness of the semi-transparent layer is 8-12 μm, and the light transmittance of the semi-transparent layer is 10%-20%.

3. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 2, characterized in that: In step S3, the perforated masking layer is printed with epoxy-modified acrylic ink, which contains 10-15% carbon black opacifier by mass. The thickness of the perforated masking layer is 10-15 μm, and the light transmittance of the perforated masking layer is ≤0.5%.

4. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 3, characterized in that: In step S4, the adhesive layer is printed using polyolefin-grafted maleic anhydride ink, the grafting rate of the polyolefin-grafted maleic anhydride ink is 1.5-2.5%, and the thickness of the adhesive layer is 12-18 μm.

5. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 4, characterized in that: In step S5, the injection molding material is either TPO or PP. When using TPO, its melt index is 8-12 g / min, and when using PP, its melt index is 10-15 g / min.

6. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 5, characterized in that: In step S5, the surface roughness Ra of the injection mold cavity is ≤0.8μm, the injection mold temperature is controlled at 40-60℃, and before the composite film is placed into the cavity, its adhesive layer surface is subjected to plasma treatment with a plasma treatment power of 300-500W and a treatment time of 3-5s.

7. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 6, characterized in that: In step S5, the light-emitting module includes a PCB substrate, LED beads, and a light guide plate. The LED beads are soldered onto the PCB substrate, and the light emission wavelength of the LED beads is 450-650nm, with a power of 0.5-1W. The light guide plate is made of PMMA material, with a thickness of 2-4mm. The light-incident surface of the light guide plate corresponds to the LED beads, and the light-emitting surface is attached to the hollowed-out shielding layer area on the back of the injection molded part.

8. The processing method of a novel concealed translucent plastic automotive airbag cover trim according to claim 7, characterized in that: In step S5, the light-emitting module and the injection molded part are assembled by snap-fit ​​connection and fixed with hot melt adhesive. The hot melt adhesive is EVA type hot melt adhesive with a melting temperature of 80-100℃.

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