Self-repairing protective film and preparation method thereof
By combining modified nano-silica with PU matrix through covalent bonding and metal coordination, and with PI micro powder filling, the hardness and wear resistance of the self-healing protective film are improved, thus resolving the contradiction between hardness and self-healing ability, making it suitable for high-risk damage scenarios.
Patent Information
- Application Number
- CN202512009945.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-02-06
AI Technical Summary
Existing self-healing protective films present a contradiction in balancing hardness and self-healing ability. Insufficient hardness easily leads to scratches that cannot be repaired, while high-hardness materials have weak repair capabilities and are difficult to apply effectively in high-risk damage scenarios.
By covalently bonding modified nano-silica to the PU matrix, a rigid support network is formed. Through the synergistic effect of metal coordination bonds and hydrogen bonds of PU soft segments, combined with PI micropowder filling the gaps in the PU skeleton, the film hardness and wear resistance are improved, while self-repair is achieved.
The self-healing protective film maintains high hardness and wear resistance while possessing excellent self-repair capabilities, making it suitable for high-risk damage scenarios.
Abstract
Description
Technical Field
[0001] This invention belongs to the field of protective film technology, and particularly relates to a self-healing protective film and its preparation method. Background Technology
[0002] Self-healing protective films are a type of functional coating / film material that can autonomously or assistedly restore its structural integrity and functional characteristics after damage. Through a pre-set repair mechanism within the material, it can heal defects and restore surface continuity after being damaged by scratches, abrasions, microcracks, etc., thereby maintaining its original protective, functional, or aesthetic performance.
[0003] From the perspective of repair trigger conditions, they can be divided into:
[0004] Self-repairing: No external stimuli (such as temperature, pressure, or light) are required; repair can be completed solely through molecular diffusion and interfacial interactions within the material itself (such as materials based on dynamic covalent bonds and supramolecular interactions).
[0005] Assisted self-healing: requires external stimuli (such as heating, ultraviolet light irradiation, solvent wetting) to initiate the repair process (such as thermally reversible cross-linked polymers, photocurable self-healing materials).
[0006] Self-healing protective films are widely used in scenarios requiring long-term protection and with a high risk of damage, such as electronic and consumer electronics products, automotive paint protection films, and anti-scratch coatings for car windows.
[0007] Although self-healing protective films have achieved some commercial applications, there are still many technical bottlenecks that limit their large-scale adoption and application in high-performance scenarios:
[0008] The contradiction between mechanical properties and self-healing: To achieve self-healing, materials usually need a certain degree of flexibility (such as a low glass transition temperature Tg), resulting in insufficient hardness, wear resistance, and impact resistance. For example, the hardness of existing transparent self-healing screen protectors is mostly between 2-4H, which is much lower than that of traditional tempered glass screen protectors, making them prone to deep scratches that cannot be repaired. On the other hand, high-hardness self-healing materials (such as ceramic-based self-healing coatings) have weak repair capabilities and cannot achieve both "scratch resistance" and "self-healing". Summary of the Invention
[0009] The purpose of this invention is to provide a self-healing protective film, which aims to solve the problems mentioned in the background art.
[0010] The present invention is implemented as follows: a self-healing protective film comprises the following raw materials in parts by weight: polycaprolactone diol: 35-40 parts, isophorone diisocyanate (IPDI): 15-18 parts, 1,4-butanediol: 4-5 parts, dimethylolpropionic acid: 3-4 parts, zinc acetate: 0.8-1.2 parts, polyethylene glycol monomethyl ether: 5-6 parts, surface-modified nano-silica: 18-22 parts, polyimide micro powder: 7-8 parts, dibutyltin dilaurate: 0.3-0.5 parts, antioxidant 1010: 0.5-0.8 parts, ultraviolet absorber UV-327: 0.4-0.6 parts, and ethyl acetate / acetone mixed solvent: to make up to a solid content of 40-45% in the system.
[0011] Another objective of this invention is to provide a method for preparing a self-healing protective film, comprising the following steps:
[0012] Add polycaprolactone diol and polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours;
[0013] Cool to 60℃, add isophorone diisocyanate and dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 1,4-butanediol and dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0014] Cool to 40℃, add surface-modified nano-silica and polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and simultaneously mechanically stir at 500r / min.
[0015] Slowly add an ethanol solution of zinc acetate with a mass concentration of 10%, and stir the reaction for 1 hour;
[0016] Finally, add antioxidant 1010 and ultraviolet absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain self-healing composite coating liquid.
[0017] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0018] The present invention provides a self-healing protective film that utilizes modified nano-silica to achieve interfacial compatibility with a PU matrix through covalent bonding (reaction of -NH2 and -NCO), avoiding uneven mechanical properties caused by agglomeration; PI micropowder fills the gaps in the PU skeleton to form a "rigid support network", improving the film's hardness and wear resistance;
[0019] Metallic coordinate bonds (Zn) 2+ The synergistic effect of hydrogen bonds between the -carboxyl group and the PU soft segment ensures self-repair at room temperature and avoids mechanical relaxation caused by excessive flow of the soft segment through the cross-linking effect of the coordination bond. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0021] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.
[0022] Example 1: A self-healing protective film, the preparation method of which includes the following steps:
[0023] Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension.
[0024] Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups.
[0025] After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
[0026] Add 35 parts of polycaprolactone diol and 5 parts of polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours.
[0027] Cool to 60℃, add 15 parts of isophorone diisocyanate and 0.3 parts of dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 4 parts of 1,4-butanediol and 3 parts of dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0028] Cool to 40℃, add 18 parts of surface-modified nano silica and 7 parts of polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and mechanically stir at 500r / min.
[0029] Slowly add 0.8 parts of an ethanol solution of zinc acetate (10% by mass) and stir the reaction for 1 hour.
[0030] Finally, add 0.5 parts of antioxidant 1010 and 0.4 parts of UV absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain the self-healing composite coating liquid.
[0031] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0032] Example 2: A self-healing protective film, the preparation method of which includes the following steps:
[0033] Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension.
[0034] Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups.
[0035] After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
[0036] Add 36 parts of polycaprolactone diol and 5 parts of polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours.
[0037] Cool to 60℃, add 16 parts of isophorone diisocyanate and 0.3 parts of dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 4 parts of 1,4-butanediol and 3 parts of dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0038] Cool to 40℃, add 19 parts of surface-modified nano silica and 7 parts of polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and mechanically stir at 500r / min.
[0039] Slowly add 0.9 parts of an ethanol solution of zinc acetate (10% by mass) and stir the reaction for 1 hour.
[0040] Finally, add 0.5 parts of antioxidant 1010 and 0.4 parts of UV absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain the self-healing composite coating liquid.
[0041] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0042] Example 3: A self-healing protective film, the preparation method of which includes the following steps:
[0043] Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension.
[0044] Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups.
[0045] After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
[0046] Add 37 parts of polycaprolactone diol and 5.5 parts of polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours.
[0047] Cool to 60℃, add 17 parts of isophorone diisocyanate and 0.4 parts of dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 4 parts of 1,4-butanediol and 3.5 parts of dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0048] Cool to 40℃, add 20 parts of surface-modified nano silica and 7.5 parts of polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and simultaneously mechanically stir at 500r / min.
[0049] Slowly add 1 part of zinc acetate ethanol solution (10% by mass) and stir the reaction for 1 hour;
[0050] Finally, add 0.6 parts of antioxidant 1010 and 0.5 parts of UV absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain the self-healing composite coating liquid.
[0051] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0052] Example 4: A self-healing protective film, the preparation method of which includes the following steps:
[0053] Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension.
[0054] Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups.
[0055] After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
[0056] Add 38 parts of polycaprolactone diol and 5.8 parts of polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours;
[0057] Cool to 60℃, add 18 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 5 parts of 1,4-butanediol and 3.8 parts of dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0058] Cool to 40℃, add 21 parts of surface-modified nano silica and 8 parts of polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and mechanically stir at 500r / min.
[0059] Slowly add 1.1 parts of an ethanol solution of zinc acetate (10% by mass) and stir the reaction for 1 hour.
[0060] Finally, add 0.7 parts of antioxidant 1010 and 0.6 parts of UV absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain the self-healing composite coating liquid.
[0061] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0062] Example 5: A self-healing protective film, the preparation method of which includes the following steps:
[0063] Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension.
[0064] Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups.
[0065] After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
[0066] Add 40 parts of polycaprolactone diol and 6 parts of polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours.
[0067] Cool to 60℃, add 18 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 5 parts of 1,4-butanediol and 4 parts of dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups.
[0068] Cool to 40℃, add 22 parts of surface-modified nano silica and 8 parts of polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and mechanically stir at 500r / min.
[0069] Slowly add 1.2 parts of an ethanol solution of zinc acetate (10% by mass) and stir the reaction for 1 hour.
[0070] Finally, add 0.8 parts of antioxidant 1010 and 0.6 parts of UV absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain the self-healing composite coating liquid.
[0071] The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.
[0072] 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, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A self-healing protective film, characterized in that, The raw materials include the following parts by weight: polycaprolactone diol: 35-40 parts, isophorone diisocyanate (IPDI): 15-18 parts, 1,4-butanediol: 4-5 parts, dimethylolpropionic acid: 3-4 parts, zinc acetate: 0.8-1.2 parts, polyethylene glycol monomethyl ether: 5-6 parts, surface-modified nano silica: 18-22 parts, polyimide micro powder: 7-8 parts, dibutyltin dilaurate: 0.3-0.5 parts, antioxidant 1010: 0.5-0.8 parts, ultraviolet absorber UV-327: 0.4-0.6 parts, ethyl acetate / acetone mixed solvent: to make up to 40-45% of the system solid content.
2. The self-healing protective film according to claim 1, characterized in that, The raw materials include the following parts by weight: polycaprolactone diol: 36-38 parts, isophorone diisocyanate (IPDI): 16-18 parts, 1,4-butanediol: 4-5 parts, dimethylolpropionic acid (DMPA): 3-3.8 parts, zinc acetate: 0.9-1.1 parts, polyethylene glycol monomethyl ether: 5-5.8 parts, surface-modified nano silica: 19-21 parts, polyimide micro powder: 7-8 parts, dibutyltin dilaurate: 0.3-0.5 parts, antioxidant 1010: 0.5-0.7 parts, ultraviolet absorber UV-327: 0.4-0.6 parts, ethyl acetate / acetone mixed solvent: to make up to 40-45% of the system solid content.
3. The self-healing protective film according to claim 2, characterized in that, The raw materials include the following parts by weight: 37 parts polycaprolactone diol, 17 parts isophorone diisocyanate (IPDI), 4 parts 1,4-butanediol, 3.5 parts dimethylolpropionic acid (DMPA), 1 part zinc acetate, 5.5 parts polyethylene glycol monomethyl ether, 20 parts surface-modified nano silica, 7.5 parts polyimide micro powder, 0.4 parts dibutyltin dilaurate, 0.6 parts antioxidant 1010, 0.5 parts UV absorber UV-327, and ethyl acetate / acetone mixed solvent to bring the system solid content to 40-45%.
4. The self-healing protective film according to claim 1, characterized in that, The preparation method of the surface-modified nano-silica includes the following steps: Take 10 parts of unmodified nano-SiO2 and disperse it in 100 parts of anhydrous ethanol. Disperse it ultrasonically for 30 minutes at 300W to form a uniform suspension. Add 1.5 parts of KH-550, heat to 60℃, and mechanically stir for 4 hours to allow the alkoxy groups of KH-550 to hydrolyze and condense with the hydroxyl groups on the surface of SiO2, thereby grafting amino groups. After the reaction was completed, the mixture was centrifuged at 8000 r / min for 15 min, washed three times with anhydrous ethanol, and dried under vacuum at 80℃ for 6 h to obtain surface-modified nano-silica for later use.
5. The self-healing protective film according to claim 1, characterized in that, The polyimide micro powder has a particle size of 1-3 μm.
6. The self-healing protective film according to claim 1, characterized in that, The volume ratio of ethyl acetate to acetone in the ethyl acetate / acetone mixed solvent is 1:
1.
7. A method for preparing a self-healing protective film as described in any one of claims 1-5, characterized in that, Includes the following steps: Add polycaprolactone diol and polyethylene glycol monomethyl ether to a four-necked flask equipped with a condenser, stirrer and constant pressure dropping funnel, heat to 80°C and dehydrate under vacuum for 2 hours; Cool to 60℃, add isophorone diisocyanate and dibutyltin dilaurate, stir and react for 3 hours under nitrogen protection to form PU prepolymer, add 1,4-butanediol and dimethylolpropionic acid in sequence, heat to 75℃ and continue to react for 2 hours to extend the chain and form a PU polymer containing carboxyl groups. Cool to 40℃, add surface-modified nano-silica and polyimide micro powder, ultrasonically disperse for 40 min at 500W power, and simultaneously mechanically stir at 500r / min. Slowly add an ethanol solution of zinc acetate with a mass concentration of 10%, and stir the reaction for 1 hour; Finally, add antioxidant 1010 and ultraviolet absorber UV-327, stir for 30 minutes, adjust the solid content of the system to 40-45% with ethyl acetate / acetone mixed solvent, filter to remove impurities, and obtain self-healing composite coating liquid. The self-healing composite coating liquid was uniformly coated on the surface of the substrate, left at room temperature for 15 minutes, dried at 60°C for 2 hours, and then dried under vacuum at 80°C for 3 hours. After cooling to room temperature, it was peeled off to obtain a self-healing protective film.