Waterproof vehicle film composite structure based on modified thermoplastic polyolefin substrate and preparation process

Abstract

The application relates to the technical field of waterproof film preparation, in particular to a waterproof car film composite structure based on a modified thermoplastic polyolefin base material and a preparation process, which comprises a composite structure layer taking thermoplastic polyolefin as a base material, and the composite structure layer has a plasma-induced continuous functional gradient in the thickness direction; wherein the surface layer region accounts for 10%-30% of the thickness and contains 15%-40% of fluoropolymer modifier and 5%-20% of nano silicon dioxide in terms of mass fraction; the inner layer region accounts for 40%-60% of the thickness and contains 0.1%-5% of double-response microcapsules in terms of mass fraction, and the elastic modulus is less than 50% of that of the surface layer region; and the gradient is formed by the migration of the modifier with the polarization direction being consistent with the thickness direction. By applying a gradient electric field-plasma in the co-extrusion process, the directional migration and gradient enrichment of the modifier along the thickness direction are completed, the composition-property continuous transition from the surface layer to the inner layer is achieved, the mechanical bonding interface is eliminated, and the peeling strength is improved.

Description

Technical Field

[0001] This invention relates to the field of waterproof membrane preparation technology, specifically to a waterproof vehicle membrane composite structure and preparation process based on a modified thermoplastic polyolefin substrate. Background Technology

[0002] Thermoplastic polyolefins are composed of two components: rubber and polyolefin. Polyolefins, such as polyethylene (PE) and polypropylene (PP), are produced into polymer materials by optimizing their properties through chemical or physical methods. Their rigidity, temperature resistance, toughness, and other properties can be improved by adding elastomers, fillers, or blending with other polymers.

[0003] Application number CN201410500195.6 discloses a superhydrophobic film, its production method, and its application. The film comprises six layers, from bottom to top: a release layer, an adhesive layer, a first polyester film layer, a composite layer, a second polyester film layer, and an anti-fog coating. This patent's superhydrophobic film possesses excellent anti-fog functionality while overcoming the energy consumption drawbacks of traditional electrically heated anti-fog films. Furthermore, the invention incorporates advantages not found in traditional anti-fog films, such as heat insulation, UV protection, and oxidation resistance. Moreover, this patent employs a multi-layer coating composite technology, thereby giving the film excellent explosion-proof properties. Additionally, the hydrophobic coating used in this invention is easy to clean and does not readily absorb moisture.

[0004] Existing automotive films mostly employ multi-layer composite technology, layering functional coatings onto a substrate to achieve waterproofing and other functions. This approach has the following drawbacks:

[0005] Physical coating results in insufficient bonding between the modified layer and the substrate, and long-term use can easily lead to delamination and failure; uniform incorporation of repair microcapsules-epoxy resin type is prematurely activated when exposed to high temperatures, and cannot accurately respond to damage. Summary of the Invention

[0006] To overcome the deficiencies in the prior art, the present invention aims to provide a waterproof automotive film composite structure and preparation process based on modified thermoplastic polyolefin substrate. This is achieved by applying a gradient electric field / plasma during co-extrusion, by precisely implanting dual-response microcapsules in the inner layer region, and by using a nickel-based imprinting tape of a dynamic pressing unit and a closed-loop temperature control system to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, on one hand, the present invention provides a waterproof automotive film composite structure based on a modified thermoplastic polyolefin substrate, comprising a composite structural layer with a thermoplastic polyolefin substrate, wherein the composite structural layer has a plasma-induced continuous functional gradient in the thickness direction; wherein:

[0008] The surface area, accounting for 10%-30% of the thickness, contains 15%-40% by mass of fluoropolymer modifier and 5%-20% of nano-silica, with a static water contact angle >160° and a roll-off angle <5°.

[0009] The inner layer, accounting for 40%-60% of the thickness, contains dual-responsive microcapsules with a mass fraction of 0.1%-5%, and its elastic modulus is less than 50% of that of the surface layer.

[0010] The gradient is formed by the migration of a modifier whose polarization direction is aligned with the thickness direction.

[0011] The above settings clearly define the gradient formation mechanism – electric field / plasma induction, gradient directionality, key component content and performance indicators, thereby enhancing functionality.

[0012] As a further improvement to this technical solution, the nano-silica is surface-treated with a perfluorosilane coupling agent, with a particle size of 20-100nm, and is arranged in a vertical orientation in the surface region.

[0013] This setting limits the surface modification and orientation characteristics of nanoparticles, thereby enhancing their hydrophobicity.

[0014] As a further improvement to this technical solution, the dual-response microcapsule contains a repair agent and a response trigger. The repair agent is composed of norbornene derivative monomers and Grubbs second-generation catalyst; the response trigger is sodium polyacrylate hydrogel microparticles or lead zirconate titanate piezoelectric microparticles with a particle size of 1-10 μm.

[0015] This setting specifies the chemical composition, response threshold, and microcapsule structural parameters of the repair agent and trigger.

[0016] As a further improvement to this technical solution, the microcapsule wall material is polyurea with a wall thickness of 0.5-2 μm and an average particle size of 20±5 μm; the distribution density of microcapsules in the inner layer region is 10. 3 -10 4 pcs / mm 3 And at least 50 μm away from the surface area.

[0017] This setting limits the location and density of microcapsules to ensure precise positioning of the repair function.

[0018] As a further improvement to this technical solution, it is applied to glass films or housing films, and the inner layer of the film is bonded to the housing with a polyolefin adhesive with a thickness of 50-200μm.

[0019] On the other hand, the present invention provides a process for preparing a waterproof automotive film based on a modified thermoplastic polyolefin substrate, used to fabricate the aforementioned waterproof automotive film composite structure based on a modified thermoplastic polyolefin substrate, wherein a modular embossing device is used for embossing and molding, the device comprising:

[0020] Replaceable embossing tape unit: composed of a high-temperature resistant nickel-based alloy tape with a thickness of 0.5-1mm, and the surface is laser-engraved with a biomimetic micro-papill array, with a papillary diameter of 5-50μm, a height of 10-100μm, and a spacing of 1-20μm;

[0021] Closed-loop temperature-controlled pressure roller system: includes a pair of steel rollers with internal cooling fluid and heating oil, steel roller diameter 300-800mm, gap between steel rollers 0.1-2mm, roller surface temperature zone control, temperature difference ±1℃, pressure provided by hydraulic servo system;

[0022] Real-time deformation monitoring module: integrates laser displacement sensor and infrared thermal imager to provide online feedback of film thickness, temperature and surface morphology data to the control system;

[0023] The pressing step includes forming a gradient functional layer through a plasma-assisted co-extrusion system and an electric field gradient control system, introducing the molten film after gradient co-extrusion into the gap between steel rollers, and dynamically adjusting according to monitoring data; pressing temperature: 15-25℃ higher than the melting point of TPO; linear pressure: 1-8kN / m; roller speed: matched with the extrusion rate.

[0024] The above settings fully define the structure of the pressing equipment - replaceable imprinting belt, temperature-controlled pressure roller, monitoring module and dynamic control logic.

[0025] As a further improvement to this technical solution, the plasma-assisted co-extrusion system includes an atmospheric pressure plasma spray gun array set at the co-extrusion die outlet, the plasma gas being a helium / oxygen mixture with He:O2=95:5, and a processing time of 0.1-2s;

[0026] The electric field gradient control system includes multiple sets of electrode plates arranged on the extrusion path with a spacing of 10-50 mm, and a DC bias voltage of 10-100 kV / cm is applied, with the voltage increasing step by step along the extrusion direction.

[0027] This setting clarifies the two implementation methods of gradient polarization and the key process parameters.

[0028] As a further improvement to this technical solution, the microcapsule embedding step uses a cryogenic syringe to inject the microcapsule suspension into the inner melt flow at a temperature of 170-190℃.

[0029] An ultrasonic diffuser is used, with a power density of 0.3-0.8 W / cm³. 3 The frequency is 28kHz, the action time is 2-10s, and the capsule breakage rate is controlled to be <1%.

[0030] This setting limits the specific implementation method and ultrasonic critical parameters of cryogenic injection.

[0031] As a further improvement to this technical solution, the biomimetic micro-papillary structure of the imprinting tape unit is preheated to 180-200℃ by steel rollers and then pressed and transferred to the film surface, with a pressing contact time of 0.5-3s.

[0032] This setting adds temperature and time parameters for microstructure transfer.

[0033] As a further improvement to this technical solution, the data from the real-time deformation monitoring module is fed back to the PID adaptive controller to dynamically adjust the temperature, pressure, and rotation speed of the pressure roller.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. The waterproof car film composite structure and preparation process based on modified thermoplastic polyolefin substrate achieves the directional migration and gradient enrichment of modifiers along the thickness direction by applying a gradient electric field-plasma during co-extrusion, thereby achieving a continuous transition of composition and performance from the surface layer to the inner layer, eliminating the mechanical bonding interface, and improving peel strength.

[0036] 2. The waterproof car film composite structure and preparation process based on modified thermoplastic polyolefin substrate achieves precise spatial positioning and conditional triggering of the repair action by precisely implanting dual-response microcapsules in the inner layer region. This ensures that the repair agent is released only when the capsule ruptures and comes into contact with water pressure or impact pressure, thus achieving targeted repair, avoiding false activation, and improving the recovery rate of waterproofness after repair. Attached Figure Description

[0037] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, will select various possible shapes and proportions to implement the invention according to specific circumstances.

[0038] Figure 1 This is a diagram illustrating the composition of the waterproof vehicle membrane composite structure of the present invention;

[0039] Figure 2 This is the overall process flow diagram of the present invention;

[0040] Figure 3 This is a diagram of the gradient-forming co-extrusion system for the waterproof vehicle film composite structure of the present invention;

[0041] Figure 4 This is a flowchart of the microcapsule embedding process of the present invention;

[0042] Figure 5 This is a flow chart of the lamination process for the modular embossing equipment of the present invention;

[0043] Figure 6 This is a schematic diagram of the closed-loop control logic of the real-time deformation monitoring module of the present invention;

[0044] Figure 7 This is a schematic diagram showing the hierarchical relationship between the overall diagram and the sub-diagrams of the present invention; Detailed Implementation

[0045] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art will conceive of any possible variations of the invention, all of which should be considered within the scope of the invention. The terms "installation" and "connection" should be interpreted broadly, referring to direct connection as well as indirect connection through an intermediate medium.

[0046] The terms "central axis," "vertical," "horizontal," "front," "rear," "upper," "lower," "left," "right," "top," "bottom," "inner," and "outer" used herein to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of the invention, "a number" means two or more, unless otherwise explicitly specified.

[0047] Please see Figures 1-7 As shown, this invention provides a waterproof automotive film composite structure based on a modified thermoplastic polyolefin substrate, comprising a composite structural layer with a thermoplastic polyolefin substrate, the composite structural layer having a plasma-induced continuous functional gradient in the thickness direction; wherein:

[0048] The surface region, with a thickness of 10%-30%, contains 15%-40% by mass of fluorinated polymer modifier and 5%-20% nano-silica. The static water contact angle is >160° and the roll-off angle is <5°. Through the directional arrangement and gradient polarization of CF3 groups on the surface, an ultra-low surface energy is formed, thereby achieving chemical hydrophobic enhancement and supporting a contact angle of >160°, ensuring that the water droplet is approximately spherical and reducing solid-liquid contact. Through vertical orientation after plasma treatment, a micro-nano secondary rough structure is constructed, thereby achieving physical hydrophobic synergy and realizing a roll-off angle of <5°, allowing water droplets to roll off a 5° inclined surface.

[0049] The inner layer, accounting for 40%-60% of the thickness, contains dual-response microcapsules with a mass fraction of 0.1%-5%, and its elastic modulus is less than 50% of that of the surface layer; the modulus gradient design is: high modulus in the surface layer → low modulus in the inner layer.

[0050] The surface layer has a high modulus (1-3 GPa): resists external scratches / gravel impacts; the inner layer has a low modulus (<0.5-1.5 GPa): absorbs impact energy, prevents microcapsules from rupturing under pressure, and improves deformation compatibility with the vehicle body adhesive; it also buffers mechanical stress, prevents microcapsules from rupturing under pressure, reduces interfacial stress, and avoids debonding from the vehicle body. The 50% ratio is a safety threshold derived from finite element analysis; values ​​below this will result in insufficient support, while values ​​above it will lead to a loss of buffering function.

[0051] The gradient is formed by the migration of modifiers whose polarization direction aligns with the thickness direction. This clarifies the gradient formation mechanism—electric field / plasma induction, gradient directionality, key component content, and performance indicators—to enhance functionality.

[0052] Furthermore, the surface modification and orientation characteristics of the nanoparticles are defined to enhance hydrophobicity. Nano-silica, surface-treated with a perfluorosilane coupling agent, has a particle size of 20-100 nm and exhibits a vertically oriented arrangement in the surface region. Through the vertical orientation of the nanoparticles and the perfluorosilane treatment, the surface energy is further reduced, ensuring a stable superhydrophobic state with a contact angle >160° and a roll-off angle <5°.

[0053] Furthermore, the chemical composition, response threshold, and microcapsule structural parameters of the repair agent and trigger are specified. The dual-response microcapsules contain a repair agent and a response trigger. The repair agent consists of norbornene derivative monomers and a Grubbs second-generation catalyst; the response trigger is sodium polyacrylate hydrogel microparticles or lead zirconate titanate piezoelectric microparticles with a particle size of 1-10 μm. Through the synergistic encapsulation of the repair agent and the trigger—hydrogel / piezoelectric microparticles—repair is activated only when the microcapsule is damaged and exposed to water or pressure, avoiding accidental release at high temperatures.

[0054] Specifically, the location and density of the microcapsules are precisely defined to ensure accurate positioning of the repair function. The microcapsule wall material is polyurea, with a wall thickness of 0.5-2 μm and an average particle size of 20±5 μm; the distribution density of the microcapsules in the inner layer region is 10. 3 -10 4 pcs / mm 3 Furthermore, the distance between the microcapsules and the surface layer should be at least 50 μm. By limiting the distance between the microcapsules and the surface layer to ≥50 μm and the distribution density, the high temperature during compression can be used to prevent damage to the wall material and ensure the survival rate of the microcapsules.

[0055] In addition, it is used in window tinting or vehicle body tinting, with the inner layer of the film bonded to the body using a polyolefin adhesive, with a thickness of 50-200μm. The reactive adhesive bonding enhances the sealing and corrosion resistance of the film and body, meeting the IP67 waterproof rating.

[0056] This invention also provides a process for preparing a waterproof automotive film based on a modified thermoplastic polyolefin substrate, used to fabricate the aforementioned waterproof automotive film composite structure based on a modified thermoplastic polyolefin substrate. The process employs a modular embossing device for pressing and molding, the device comprising:

[0057] Replaceable embossing tape unit: composed of a high-temperature resistant nickel-based alloy tape with a thickness of 0.5-1mm, and the surface is laser-engraved with a biomimetic micro-papill array, with a papillary diameter of 5-50μm, a height of 10-100μm, and a spacing of 1-20μm;

[0058] Closed-loop temperature-controlled pressure roller system: includes a pair of steel rollers with internal cooling fluid and heating oil, steel roller diameter 300-800mm, gap between steel rollers 0.1-2mm, roller surface temperature zone control, temperature difference ±1℃, pressure provided by hydraulic servo system;

[0059] Real-time deformation monitoring module: integrates laser displacement sensor and infrared thermal imager to provide online feedback of film thickness, temperature and surface morphology data to the control system;

[0060] The pressing step includes forming a gradient functional layer through a plasma-assisted co-extrusion system and an electric field gradient control system, introducing the molten film after gradient co-extrusion into the gap between steel rollers, and dynamically adjusting according to monitoring data; pressing temperature: 15-25℃ higher than the melting point of TPO; linear pressure: 1-8kN / m; roller speed: matched with the extrusion rate.

[0061] By using a nickel-based imprinting tape in a dynamic pressing unit and a closed-loop temperature control system, biomimetic micro-papillary arrays are simultaneously transferred while densifying the interlayer, achieving surface micro-nano structure forming precision, contact angle >160°, and improved process efficiency.

[0062] Furthermore, the two implementation methods and key process parameters of gradient polarization are clarified. The plasma-assisted co-extrusion system includes an atmospheric pressure plasma spray gun array at the co-extrusion die exit, with the plasma gas being a helium / oxygen mixture (He:O2=95:5) and a processing time of 0.1-2 seconds. The electric field gradient control system includes multiple sets of electrode plates arranged along the extrusion path, spaced 10-50 mm apart, applying a DC bias voltage of 10-100 kV / cm, with the voltage increasing progressively along the extrusion direction. Through precise control of plasma and electric field parameters, a gradient distribution of the modifier is achieved, resulting in the desired peel strength.

[0063] Furthermore, the specific implementation method and ultrasonic critical parameters for cryogenic injection are defined. Specifically, the microcapsule embedding step uses a cryogenic injector to inject the microcapsule suspension into the inner melt flow at a temperature of 170-190℃; an ultrasonic disperser is used with a power density of 0.3-0.8 W / cm³. 3The frequency was 28kHz, the action time was 2-10s, and the capsule breakage rate was controlled to be <1%. Low-temperature injection and critical ultrasound were used to ensure uniform microcapsule dispersion and a breakage rate of <1%, maintaining repair effectiveness.

[0064] Furthermore, the temperature and time parameters for microstructure transfer are increased. The biomimetic micro-papillary structure of the imprinting belt unit is preheated to 180-200℃ by steel rollers and then pressed and transferred to the film surface, with a pressing contact time of 0.5-3 seconds. By controlling the preheating of the imprinting belt and the contact time, high-fidelity transfer of the micro-papillary structure is achieved.

[0065] Furthermore, data from the real-time deformation monitoring module is fed back to the PID adaptive controller, which dynamically adjusts the temperature, pressure, and speed of the pressure roller. Through the linkage between the laser displacement sensor and the PID adaptive controller, real-time closed-loop control of multiple parameters such as pressing temperature, linear pressure, and roller speed is achieved, thereby realizing low microcapsule breakage rate and stable distribution of gradient polarization modifier.

[0066] It should be noted that the fixed connections and fixing methods of the present invention are achieved using conventional fixing means such as bolt connections or welding. The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A waterproof vehicle film composite structure based on a modified thermoplastic polyolefin elastomer substrate, characterized in that, It includes a composite structural layer based on a thermoplastic polyolefin elastomer, wherein the composite structural layer has a plasma-induced continuous functional gradient in the thickness direction; wherein: The surface area, accounting for 10%-30% of the thickness, contains 15%-40% by mass of fluoropolymer modifier and 5%-20% of nano-silica, with a static water contact angle >160° and a roll-off angle <5°. The inner layer, accounting for 40%-60% of the thickness, contains dual-responsive microcapsules with a mass fraction of 0.1%-5%, and the elastic modulus of the inner layer is less than 50% of that of the surface layer. The gradient is formed by the migration of a modifier whose polarization direction is consistent with the thickness direction; The dual-response microcapsules contain a repair agent and a response trigger. The repair agent is composed of norbornene derivative monomers and Grubbs second-generation catalysts. The response trigger consists of sodium polyacrylate hydrogel microparticles with a particle size of 1-10 μm and lead zirconate titanate piezoelectric microparticles.

2. The waterproof vehicle film composite structure based on a modified thermoplastic polyolefin elastomer substrate according to claim 1, characterized in that: The nano-silica is surface-treated with a perfluorosilane coupling agent, has a particle size of 20-100 nm, and is arranged in a vertical orientation in the surface region.

3. The waterproof vehicle film composite structure based on a modified thermoplastic polyolefin elastomer substrate according to claim 2, characterized in that: The microcapsule wall material is polyurea, with a wall thickness of 0.5-2 μm and an average particle size of 20±5 μm; the distribution density of microcapsules in the inner layer region is 10³-10⁻¹⁰. 4 Each element per mm³, and at least 50 μm from the surface area.

4. The waterproof vehicle film composite structure based on a modified thermoplastic polyolefin elastomer substrate according to claim 3, characterized in that: It is used in glass film or housing film, and the inner layer of the film is bonded to the housing with polyolefin adhesive, with a thickness of 50-200μm.

5. A process for preparing a waterproof vehicle film based on a modified thermoplastic polyolefin elastomer substrate, used to manufacture the waterproof vehicle film composite structure based on a modified thermoplastic polyolefin elastomer substrate as described in any one of claims 1-4, characterized in that: Compression molding is performed using a modular embossing device, which includes: Replaceable embossing tape unit: composed of a high-temperature resistant nickel-based alloy tape with a thickness of 0.5-1mm, and the surface is laser-engraved with a biomimetic micro-papill array, with a papillary diameter of 5-50μm, a height of 10-100μm, and a spacing of 1-20μm; Closed-loop temperature-controlled pressure roller system: includes a pair of steel rollers with internal cooling fluid and heating oil, steel roller diameter 300-800mm, gap between steel rollers 0.1-2mm, roller surface temperature zone control, temperature difference ±1℃, pressure provided by hydraulic servo system; Real-time deformation monitoring module: integrates laser displacement sensor and infrared thermal imager to provide online feedback of film thickness, temperature and surface morphology data to the control system; The pressing step includes forming a gradient functional layer through a plasma-assisted co-extrusion system and an electric field gradient control system, introducing the molten film after gradient co-extrusion into the gap between steel rollers, and dynamically adjusting according to monitoring data; pressing temperature: 15-25℃ higher than the melting point of TPO; linear pressure: 1-8kN / m; roller speed: matched with the extrusion rate.

6. The process for preparing a waterproof vehicle film based on a modified thermoplastic polyolefin elastomer substrate according to claim 5, characterized in that: The plasma-assisted co-extrusion system includes an atmospheric pressure plasma spray gun array set at the co-extrusion die outlet, the plasma gas being a helium / oxygen mixture with He:O2=95:5, and a processing time of 0.1-2s; The electric field gradient control system includes multiple sets of electrode plates arranged on the extrusion path with a spacing of 10-50 mm, and a DC bias voltage of 10-100 kV / cm is applied, with the voltage increasing step by step along the extrusion direction.

7. The process for preparing a waterproof vehicle film based on a modified thermoplastic polyolefin elastomer substrate according to claim 6, characterized in that: The microcapsule embedding step involves injecting the microcapsule suspension into the inner melt flow using a cryogenic syringe at a temperature of 170-190℃. An ultrasonic disperser was used with a power density of 0.3-0.8 W / cm³, a frequency of 28 kHz, and an action time of 2-10 s to control the capsule breakage rate to <1%.

8. The process for preparing a waterproof vehicle film based on a modified thermoplastic polyolefin elastomer substrate according to claim 7, characterized in that: The biomimetic micro-papill array structure of the imprinting tape unit is preheated to 180-200℃ by steel rollers and then pressed and transferred to the film surface, with a pressing contact time of 0.5-3s.

9. The process for preparing a waterproof vehicle film based on a modified thermoplastic polyolefin elastomer substrate according to claim 8, characterized in that: The data from the real-time deformation monitoring module is fed back to the PID adaptive controller, which dynamically adjusts the temperature, pressure, and rotation speed of the pressure roller.

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