Scratch self-repairing type epoxy coiled material as well as preparation method and repairing method thereof

Abstract

The invention relates to the technical field of functional epoxy coiled materials, in particular to a scratch self-repairing type epoxy coiled material as well as a preparation method and a repairing method thereof. The invention provides a scratch self-repairing type epoxy coiled material. The scratch self-repairing type epoxy coiled material comprises a surface layer, a middle layer and a bottom layer from bottom to top, each of the surface layer, the middle layer and the bottom layer comprises at least one layer of epoxy resin coating; the middle layer and / or the bottom layer further comprises at least one fiber reinforced layer; the epoxy resin coating comprises an epoxy resin matrix, a flexibilizer, a curing agent containing disulfide bonds and amino groups, and a curing accelerator. According to the scratch self-repairing type epoxy coiled material provided by the invention, disulfide bond dynamic crosslinking points are introduced into an epoxy resin system, and a low-Tg micro-area structure formed by polyethylene glycol is combined, so that the material can simultaneously trigger free radical exchange reaction and flexible chain segment migration of disulfide bonds under local slight temperature rise. Through the synergistic effect of the two components, molecular rearrangement and interface healing can be realized in a short time, scratches are rapidly closed, the original performance of the scratches is recovered, and an additional repairing agent is not needed.

Description

Technical Field

[0001] This invention relates to the field of functional epoxy roll material technology, specifically to a scratch-repairing self-healing epoxy roll material and its preparation and repair methods. Background Technology

[0002] Epoxy resins are widely used in floor coatings, electronic packaging, composite materials, and high-end structural components due to their excellent mechanical properties, chemical resistance, and electrical insulation. However, in practical applications, epoxy rolls are prone to surface damage during installation and transportation due to improper handling, and are also easily scratched by mechanical friction during installation or use. These scratches not only affect the appearance of the epoxy rolls but may also weaken their anti-corrosion and sealing properties, thereby shortening their service life.

[0003] Existing methods for repairing scratches on epoxy roofing membranes mainly include thermally activated repair, photo-induced repair, and external chemical repair. While these methods can restore surface defects to some extent, they generally suffer from slow response times, high energy consumption, complex operation, or unsatisfactory repair efficiency. Furthermore, these methods often struggle to achieve efficient repair in complex environments or field applications, limiting their widespread adoption and application.

[0004] Therefore, how to construct a functional structure in epoxy membranes that can respond quickly and achieve self-healing after scratches, and reduce dependence on external repair conditions, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] This invention provides a scratch-resistant self-healing epoxy roofing membrane, its preparation method, and its repair method. The self-healing epoxy roofing membrane introduces dynamic cross-linking points of disulfide bonds through curing, combined with a low-Tg flexible micro-region structure formed by polyethylene glycol. This allows the material to simultaneously trigger free radical exchange reactions of disulfide bonds and flexible chain segment migration under slight localized heating, giving the epoxy roofing membrane self-healing capabilities.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a scratch-resistant self-healing epoxy roll material, comprising a top layer, a middle layer, and a bottom layer from bottom to top; each of the top layer, middle layer, and bottom layer comprises at least one layer of epoxy resin coating; the middle layer and / or the bottom layer further comprises at least one layer of fiber reinforcement. The epoxy resin coating includes: an epoxy resin matrix, a toughening agent, a curing agent containing disulfide bonds and amino groups, and a curing accelerator.

[0007] Epoxy resin coatings for self-healing scratch-resistant epoxy roofing membranes use epoxy resin as the matrix material and introduce toughening agents to construct flexible, migratable segments, maintaining the strength and toughness of the entire epoxy resin system at a level suitable for roofing membranes. Secondly, during the curing process, the amino groups in the curing agent molecules undergo a cross-linking reaction with the epoxy groups in the epoxy resin matrix, allowing disulfide bond-containing structural units to be embedded into the epoxy resin network through curing. Because curing agents containing disulfide bonds and amino groups have a slow curing rate, an appropriate amount of curing accelerator needs to be added to the system to accelerate the reaction process, ensuring sufficient cross-linking and a stable network structure. Finally, the disulfide bonds are effectively fixed in the cured cross-linked network.

[0008] Epoxy rolls cured with epoxy resin coatings not only form micro-regions with low glass transition temperature (Tg) and abundant flexible segments, but also introduce dynamically reversible disulfide bonds into the crosslinking network. These dynamic bonds can undergo molecular rearrangement through free radical homolytic cleavage and exchange reactions under heating conditions, thus endowing the material with thermally triggered self-healing properties. When the surface of the epoxy roll is scratched, localized heating can simultaneously activate flexible segment migration and disulfide bond rearrangement. The synergistic effect of these two processes allows the damaged area to be filled and the interface to heal, achieving highly efficient self-healing functionality.

[0009] Here, the applicant would like to emphasize that epoxy roofing membranes and coatings differ fundamentally in structure and performance. Coatings generally exhibit high mobility, which is compatible with the dynamic movement of disulfide bonds, making self-healing easier to achieve. However, for products with high crystallinity or those with a certain degree of rigidity and hardness, such as epoxy roofing membranes, and considering the thermosetting and lamination processes involved in their preparation, the movement of disulfide bonds is restricted. Therefore, successfully achieving self-healing properties in epoxy roofing membranes by utilizing disulfide bonds presents challenges from the product's manufacturing perspective. The applicant has obtained the currently achievable self-healing epoxy resin coating formulation through the selection and combination of various raw materials.

[0010] The method of this invention does not require the introduction of external repair agents and can achieve multiple reversible scratch self-repairs under normal or low temperature conditions, effectively restoring the integrity and functional characteristics of epoxy rolls, and significantly improving the scratch resistance and service life of epoxy rolls.

[0011] Preferably, the molar ratio between the epoxy groups in the epoxy resin matrix and the amino groups in the curing agent containing disulfide bonds and amino groups is (2~1):1.

[0012] Preferably, the epoxy resin matrix comprises at least bisphenol A diglycidyl ether, and further comprises at least one of bisphenol A type epoxy resin or butyl glycidyl ether; and / or, the toughening agent is polyethylene glycol; and / or, the curing agent containing disulfide bonds and amino groups is 2,2'-diaminodiphenyl disulfide; and / or, the curing accelerator is zinc acetylacetonate; and / or, the epoxy resin coating further comprises at least one of filler, additive, or color paste; and / or, the fiber reinforcement layer is glass fiber and / or polyester fiber; and / or, the epoxy resin matrix comprises at least 40 wt% bisphenol A diglycidyl ether.

[0013] Preferably, the epoxy resin matrix comprises at least 45 wt% bisphenol A diglycidyl ether.

[0014] Preferably, in the top layer, the epoxy resin matrix comprises at least 45 wt% bisphenol A diglycidyl ether; in the middle layer, the epoxy resin matrix comprises at least 38 wt% bisphenol A diglycidyl ether; and in the bottom layer, the epoxy resin matrix comprises at least 42 wt% bisphenol A diglycidyl ether.

[0015] More preferably, in the top layer, the epoxy resin matrix includes at least 48 wt% bisphenol A diglycidyl ether; in the middle layer, the epoxy resin matrix includes at least 39 wt% bisphenol A diglycidyl ether; and in the bottom layer, the epoxy resin matrix includes at least 44 wt% bisphenol A diglycidyl ether.

[0016] Epoxy resin coatings can be modified with colorants, additives, and fillers to control the color, aesthetics, and mechanical properties of the roll material, depending on specific needs. Colorants provide color for scratch-resistant self-healing epoxy roll materials, satisfying their decorative and aesthetic requirements. RAL7035 is commonly used, but other colorants in various color families can also be used; the choice of colorant has no impact on the performance or structure of the epoxy roll material. Different additives and fillers can improve anti-aging, abrasion resistance, or anti-slip properties.

[0017] The fiber reinforcement layer helps enhance the strength of the middle and bottom layers, improving the overall mechanical strength and scratch resistance of the epoxy roll. While achieving self-healing, it also reduces the possibility of damage; these two characteristics together determine the long service life of scratch-self-healing epoxy rolls.

[0018] Preferably, the mass ratio of bisphenol A diglycidyl ether to the toughening agent is (2.5~3.5):1. More preferably, the mass ratio of bisphenol A diglycidyl ether to the toughening agent is 3:1.

[0019] Preferably, the filler is at least one of nanoparticles, talc, or fumed silica; and the additive is at least one of polydimethylsiloxane, bentonite, or kaolin.

[0020] Preferably, by weight, each layer of the surface epoxy resin coating comprises: 65-75 parts epoxy resin matrix, 10-16 parts toughening agent, 10-15 parts curing agent containing disulfide bonds and amino groups, and 0.01-0.1 parts curing accelerator; and / or, by weight, each layer of the middle epoxy resin coating comprises: 40-50 parts epoxy resin matrix, 4-8 parts toughening agent, 5-10 parts curing agent containing disulfide bonds and amino groups, and 0.01-0.1 parts curing accelerator; and / or, by weight, each layer of the bottom epoxy resin coating comprises: 25-30 parts epoxy resin matrix, 3-6 parts toughening agent, 3-5 parts curing agent containing disulfide bonds and amino groups, and 0.01-0.1 parts curing accelerator.

[0021] Preferably, by weight, each layer of the surface epoxy resin coating comprises: 65-75 parts epoxy resin matrix, 10-16 parts toughening agent, 10-15 parts curing agent containing disulfide bonds and amino groups, 0.01-0.1 parts curing accelerator, 1-5 parts filler, and 6-7 parts additives; and / or, by weight, each layer of the intermediate epoxy resin coating comprises: 40-50 parts epoxy resin matrix, 4-8 parts toughening agent, 5-10 ... and 0.01-0.1 parts curing accelerator, 1-5 parts filler, and 6-7 parts additives. The coating comprises, by weight, a curing agent containing disulfide bonds and amino groups, 0.01 to 0.1 parts of curing accelerator, 30 to 40 parts of filler, 2 to 3 parts of additives, and 7 to 8 parts of color paste; and / or, each layer of the epoxy resin coating of the substrate comprises, by weight, 25 to 30 parts of epoxy resin matrix, 3 to 6 parts of toughening agent, 3 to 5 parts of curing agent containing disulfide bonds and amino groups, 0.01 to 0.1 parts of curing accelerator, 50 to 60 parts of filler, 3 to 5 parts of additives, and 3 to 4 parts of color paste.

[0022] This invention also provides a method for preparing a scratch-resistant self-healing epoxy roll material, comprising: S1. Epoxy resin coatings are thermosetting to form a surface layer; Epoxy resin coatings are applied to the surface of S2 and S1, and / or fiber reinforcement layers are superimposed. After thermosetting, an intermediate layer is formed on the surface. Epoxy resin coatings are applied to the middle layers of S3 and S2, and / or fiber reinforcement layers are superimposed. After heat curing, an underlayer is formed on the middle layer to obtain a scratch-resistant self-healing epoxy roll material.

[0023] Preferably, in S1 to S3, the heat curing temperature is 85 to 135°C, and the heat curing time is 30 to 50 minutes.

[0024] The present invention also provides a method for repairing scratch-resistant self-healing epoxy rolls, comprising: heating the scratch-resistant self-healing epoxy rolls with scratches at 75~85℃ for 20~40 min, so that the chain segments in the scratched area migrate, rearrange and achieve interface healing.

[0025] After repair, the width of the self-healing epoxy membrane is reduced by more than 95% compared to the initial scratch. Furthermore, under the same heating conditions, the self-healing epoxy membrane can maintain a high degree of structural integrity even after more than three repeated repairs. This demonstrates that the repair method provided in this application relies entirely on the self-movement of the self-healing epoxy membrane, providing only a thermal environment without applying any external forces, thus allowing the structure to be completely preserved.

[0026] Here, the heating temperature for repair is limited to 75~85℃, which does not mean that self-repair cannot be achieved at lower temperatures. When the temperature is lower, the repair time is longer; when the temperature is higher, the repair time is shorter. The applicant has comprehensively considered energy consumption and time costs, and only believes that heating at 75~85℃ for 20~40 minutes to achieve self-repair is the best process condition. Temperature and time are not limitations on the repair scheme of this application.

[0027] Therefore, the present invention has the following beneficial effects: (1) The scratch-healing epoxy roll material provided by this invention introduces dynamic cross-linking points of disulfide bonds into the epoxy resin system, and combines them with the low Tg micro-region structure formed by polyethylene glycol, so that the material can simultaneously trigger the free radical exchange reaction of disulfide bonds and the migration of flexible chain segments under local slight heating (about 75~85℃). The synergistic effect of the two can achieve molecular rearrangement and interface healing in a short time, quickly close the scratch and restore its original properties, and no additional repair agent is required.

[0028] (2) The scratch-repairing epoxy roll provided by the present invention can be repeatedly repaired under normal temperature or low temperature conditions, with high repair efficiency, while maintaining the structural integrity and functionality of the roll, effectively solving the problems of slow response and low efficiency of traditional thermal activation or chemical repair.

[0029] (3) In this invention, 2,2'-diaminodiphenyl disulfide is selected as the common source of disulfide bond and amino group. It can not only introduce disulfide bond into epoxy resin system, but also introduce disulfide bond in the manner of curing and crosslinking of amino and epoxy groups. This results in a curing and crosslinking effect between disulfide bond and epoxy resin system that is higher than that of simple physical mixing. This effect helps to achieve the overall self-repair of scratch self-healing epoxy roll material.

[0030] (4) The scratch-resistant self-healing epoxy roll provided by the present invention has significantly better overall rigidity, wear resistance and scratch resistance than traditional single-layer epoxy coating rolls by superimposing fiber reinforcement layers in the middle and bottom layers and optimizing the epoxy resin ratio. Attached Figure Description

[0031] Figure 1 The diagram shows the state change of the scratch-resistant self-healing epoxy roll material provided by this invention as heating time increases. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0033] The raw materials used in this section are sourced as follows: Bisphenol A diglycidyl ether, Nanya NPSN901×75, and butyl glycidyl ether were purchased from Wanqing Chemical Technology Co., Ltd. 2,2'-Diaminodiphenyl disulfide, glycerol triglycidyl ether, N,N-dimethylbenzylamine, 4,4'-diaminodiphenyldimethylethane, and zinc acetylacetone were purchased from Shanghai Maclean Biochemical Technology Co., Ltd. ZM additive (polydimethylsiloxane), ZZ additive (bentonite), ZD additive (kaolin), polyethylene glycol (PEG-400), trimethylolpropane triglycidyl ether, and C... 12-14 Alkyl glycidyl ether was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Nanopowder, talc, and fumed silica were purchased from Shanggao County Huagui Mining Co., Ltd. RAL7035 light gray paste was purchased from Suzhou Aolaixin Building Materials Co., Ltd.

[0034]

Example

[0035] Prepare epoxy resin coating B for the middle layer of epoxy roll material according to the proportions in Table 2, wherein the molar ratio between the epoxy groups in the epoxy resin matrix and the amino groups in 2,2'-diaminodiphenyl disulfide is 2:1.

[0036] Prepare epoxy resin coating C for epoxy roll base layer according to the proportions in Table 3, wherein the molar ratio between the epoxy groups in the epoxy resin matrix and the amino groups in 2,2'-diaminodiphenyl disulfide is 1.5:1.

[0037] (2) Preparation of scratch-resistant self-healing epoxy roll material ① Set the coating thickness to 0.35mm±0.05mm on the coating machine and evenly coat the epoxy resin coating A onto the base film treated with the release agent; place it in a constant temperature oven and heat and cure at 120℃ for 30 minutes to obtain the scratch-resistant self-healing epoxy roll surface layer.

[0038] ② Set the coating thickness to 0.6mm±0.05mm, apply epoxy resin coating B evenly to the surface of the cured self-healing epoxy roll material, then attach glass fiber to epoxy resin coating B, naturally remove air bubbles, and heat and cure in a constant temperature drying oven at 120℃ for 30 minutes to obtain the semi-finished epoxy roll material.

[0039] ③ Set the coating thickness to 1.20mm±0.05mm. Use a coating machine to evenly coat the epoxy resin coating C onto the glass fiber layer of the semi-finished epoxy roll material. Then attach the polyester fiber onto the epoxy resin coating C, naturally remove the air bubbles, and heat and cure in a constant temperature drying oven at 120℃ for 30 minutes to obtain a double-fiber scratch-healing epoxy roll material.

[0040] (1) The raw material formulas for each layer are shown in the table below: Table 1 Formulation ratio of epoxy resin coating A / topcoat

[0041] Table 2 Formulation ratio of epoxy resin coatings B / intermediate layer

[0042] Table 3 Formulation ratio of epoxy resin coatings C / primer

[0043] Example 2 This embodiment is basically the same as embodiment 1, except that: "(2) Step ③ of preparing scratch self-healing epoxy roll material" does not add polyester fiber, and the obtained is a single fiber scratch self-healing epoxy roll material.

[0044] The single-fiber roll material has slightly lower scratch self-healing performance and mechanical properties compared to the dual-fiber roll material, but it still has reversible self-healing function and is suitable for use in light-load or non-high-strength scenarios.

[0045] Comparative Example 1: Different Epoxy Groups This comparative example is basically the same as Example 2, except that in each layer of epoxy resin coating, bisphenol A diglycidyl ether (DGEBA) is replaced with glycerol triglycidyl ether (TMPTE), and the total mass of DGEBA and TMPTE used is the same as the amount of DGEBA used in each layer of epoxy resin coating in Example 2. The epoxy resin coatings are divided into groups 1 to 4 according to the DGEBA:TMPTE mass ratio: group 1 has a mass ratio of 90:10, group 2 has a mass ratio of 70:30, group 3 has a mass ratio of 50:50, and group 4 has a mass ratio of 0:100.

[0046] The results show that: Group 1. When TMPTE replacement is ≤10% (DGEBA:TMPTE = 90:10), the sample shows no significant difference from Example 2 (100% DGEBA) in terms of self-healing ability and basic properties of the roll material, with only a slight increase detected in the crosslinking density measurement.

[0047] Group 2. When the replacement ratio increased to 30% (70:30), the samples showed a decrease in self-healing efficiency and a significant decrease in scratch closure rate under the same thermal activation conditions; at the same time, the elongation and impact toughness of the material decreased significantly, and the surface showed a tendency for fine cracks.

[0048] Group 3. When the replacement ratio reaches 50% (50:50) or above, the self-repair of the sample is basically lost or significantly hindered. Under the given heating conditions, disulfide bond rearrangement and chain segment migration cannot occur effectively. The roll material becomes harder and more brittle, the film / rolling properties deteriorate, cracking or pinholes are prone to occur, and the bonding / peeling performance is reduced.

[0049] When 4 groups were replaced with 100% (0:100), the crosslinking density of the resulting epoxy system increased significantly, the network rigidity increased significantly after curing, the material almost lost its heat-triggered self-healing ability and could hardly meet the flexibility and ductility requirements of the roll material.

[0050] Comparative Example 2: Different Curing Accelerators This comparative example is basically the same as Example 2, except that the curing accelerator zinc acetylacetonate is replaced with an equal amount of 2,4,6-tris(dimethylaminomethyl)phenol or N,N-dimethylbenzylamine.

[0051] When using 2,4,6-tris(dimethylaminomethyl)phenol or N,N-dimethylbenzylamine as a curing accelerator to prepare scratch-self-healing epoxy roofing membranes, the curing temperature can be reduced from 120℃ to 80℃. However, because organic tertiary amine catalysts (such as 2,4,6-tris(dimethylaminomethyl)phenol and N,N-dimethylbenzylamine) activate epoxy groups and promote their strong nucleophilic ring-opening reaction with amino groups, the epoxy system rapidly forms a dense three-dimensional cross-linked network in a short time. This over-cross-linked structure significantly restricts the migration of chain segments and the dynamic rearrangement of disulfide bonds, thus causing the resulting roofing membrane to essentially lose its self-healing ability.

[0052] Comparative Example 3: Different Toughening Agents This comparative example is basically the same as Example 2, except that the toughening agent polyethylene glycol is replaced with an equal amount of trimethylolpropane triglycidyl ether or C 12-14 Alkyl glycidyl ether.

[0053] The results showed that when polyethylene glycol was replaced by trimethylolpropane triglycidyl ether, the latter, being a multifunctional epoxy monomer, significantly increased the crosslinking density of the system, leading to an excessively rigid and insufficiently tough material after curing, exhibiting a hard but brittle nature and prone to cracking. Conversely, when polyethylene glycol was replaced by C... 12-14 When alkyl glycidyl ethers are substituted, they can play a diluting and softening role in the system because they only have a monofunctional epoxy structure and contain long-chain alkyl groups. However, if the amount added is too high, it will reduce the crosslinking density and make molding difficult. If the amount added is too low, it will be difficult to form an effective flexible chain segment adjustment effect, and the material will still exhibit brittle and crack-prone characteristics.

[0054] Comparative Example 4: Curing Agents with Different Proportions This comparative example is basically the same as Example 2, except that the curing agent 2,2'-diaminodiphenyl disulfide is partially replaced with 4,4'-diaminodiphenyl dimethane. The total mass of the curing agent used is the same as the amount of 2,2'-diaminodiphenyl disulfide used in each layer of epoxy resin coating in Example 2. The molar ratios of 2,2'-diaminodiphenyl disulfide to 4,4'-diaminodiphenyl dimethane are divided into groups 1 to 3, with group 1 having a molar ratio of 1:1, group 2 having a molar ratio of 1.5:1, and group 3 having a molar ratio of 2:1.

[0055] The results showed that none of the epoxy roll materials obtained in groups 1-3 possessed self-healing properties. This is because 4,4'-diaminodiphenyldimethylethane is a highly reactive aromatic diamine curing agent, which significantly accelerates the ring-opening curing rate of epoxy groups, causing the system to form a dense and highly cross-linked three-dimensional network structure in a short time. This excessively cross-linked structure restricts the mobility of molecular chain segments and fixes the disulfide bonds, which could originally undergo dynamic exchange, within a rigid network, preventing effective bond exchange and chain rearrangement. Consequently, the material loses its thermally triggered self-healing ability.

[0056] [Performance Testing] The self-healing method involves heating the scratched self-healing epoxy roll at 80°C for 30 minutes, causing the chain segments in the scratched area to migrate, rearrange, and achieve interface healing. The scratches are created using a utility knife on the cleaned roll surface, with predetermined length, width, and depth. The degree of self-healing is assessed by comparing the length, width, and depth of the scratches before and after repair.

[0057] The indicator detection methods in this section are as follows: The pencil hardness of the sample was tested according to the test standard GB-T 6739-2022 "Determination of Hardness of Paint and Varnish Film by Pencil Method". The instrument used was an automatic pencil hardness tester (ST-5608, Xiamen, China).

[0058] The Shore D hardness of the samples was tested according to the standard GB / T 2411-2008 "Determination of indentation hardness of plastics and hard rubber using a hardness tester".

[0059] The bending properties of the samples were tested according to the standard GB / T 11982.1-2015 Polyvinyl Chloride Roll Flooring Part 1: Non-homogeneous Polyvinyl Chloride Roll Flooring. The instrument used was a bending tester (QTY-32, Shanghai, China).

[0060] Table 4 Comparison of Epoxy Roll Material Performance

[0061] The experimental results of Comparative Examples 1-4 clearly show that the self-healing performance of the system in this invention depends on the rearrangement of dynamic disulfide bonds and the migration of flexible segments, both of which are closely related to the crosslinking density, curing rate, and network flexibility of the system. Each comparative example verifies the necessity of the "synergistic effect of dynamic bonds and flexible segments" in the system design from different perspectives.

[0062] Comparative Example 1 (where DGEBA was partially or completely replaced by glycerol triglycidyl ether) showed that when the functionality of the epoxy monomer is too high, the crosslinking density of the system increases significantly, the migration space of the chain segments is restricted, and the disulfide bonds are difficult to undergo dynamic exchange, resulting in a sharp decline in self-healing efficiency.

[0063] Comparative Example 2 (organic tertiary amine catalyst replacing zinc acetylacetone) illustrates that excessively strong catalytic activity can cause the curing reaction rate to be too fast, leading to the rapid formation of an overly dense cross-linked network in the system, which disrupts the dynamic adjustment space of the flexible chain segments and ultimately results in the loss of self-healing function.

[0064] Comparative Example 3 (polyethylene glycol replaced by alkyl glycidyl ether) further verified the key role of flexible segments in the system. While multifunctional epoxy monomers (trimethylolpropane triglycidyl ether) improved the system's rigidity, they sacrificed flexibility and self-healing properties; monofunctional long-chain epoxy monomers (C... 12-14 While alkyl glycidyl ethers can soften the system, they are difficult to balance crosslinking uniformity and molding performance, resulting in unstable roll material performance.

[0065] Comparative Example 4 (2,2'-diaminodiphenyl disulfide was partially replaced with 4,4'-diaminodiphenyl dimethane) shows that excessively high activity of the curing agent can cause the system to form a rigid and dense network in a short time, making it impossible for disulfide bonds to undergo reversible exchange under thermal activation conditions, thus completely losing its self-healing ability.

[0066] In summary, the various pairs of proportions collectively reveal that: (1) There is a balance between self-healing performance and crosslinking density, curing rate and flexible segment ratio.

[0067] (2) When the system is over-crosslinked or cured too quickly, both chain segment migration and bond exchange are inhibited; when the flexible chain segments are insufficient or the proportion is inappropriate, the self-healing efficiency also decreases significantly.

[0068] This invention achieves efficient scratch self-repair under mild heating conditions by synergistically controlling the functionality of epoxy monomers, the proportion of flexible segments, and the catalytic curing rate in molecular structure design, thereby enabling the dynamic reaction of disulfide bonds and segment migration to be activated simultaneously.

[0069] Therefore, these comparative results fully demonstrate that the design concept of "dynamic cross-linking points of disulfide bonds + low Tg flexible segment micro-region structure" adopted in this invention is reasonable and necessary. This design, while ensuring the mechanical strength and film-forming properties of the roll material, achieves a heat-triggered self-healing function, demonstrating significant technological advancement and practical value.

Claims

1. A scratch self-repairing type epoxy roll material, characterized by, comprise from bottom to top a top layer, a middle layer and a bottom layer; each of the top layer, the middle layer and the bottom layer comprises at least one layer of epoxy coating; the middle layer and / or the bottom layer further comprises at least one layer of fiber reinforced layer; the epoxy coating comprises an epoxy resin matrix, a toughening agent, a curing agent containing disulfide bond and amino group and a curing accelerator.

2. The scratch self-repairing epoxy roll material according to claim 1, wherein, The molar ratio between the epoxy groups in the epoxy resin matrix and the amino groups in the curing agent containing disulfide bond and amino group is (2-1):

1.

3. The scratch self-repairing epoxy roll material according to claim 1, wherein, The epoxy resin matrix at least comprises bisphenol A diglycidyl ether, and further comprises at least one of bisphenol A epoxy resin or butyl glycidyl ether; and / or, the toughening agent is polyethylene glycol; and / or, the curing agent containing disulfide bond and amino group is 2,2'-diamino diphenyl disulfide; and / or, the curing accelerator is zinc acetylacetone; and / or, the epoxy coating further comprises at least one of filler, auxiliary agent or color paste; and / or, the fiber reinforced layer is glass fiber and / or polyester fiber; and / or, the epoxy resin matrix at least comprises 40 wt% of bisphenol A diglycidyl ether.

4. The scratch self-repairing epoxy roll material according to claim 3, wherein, The mass ratio of the bisphenol A diglycidyl ether to the toughening agent is (2.5-3.5):

1.

5. The scratch self-repairing epoxy roll material according to claim 3 or 4, wherein, The filler is at least one of nano powder, talc powder or gas silicon; the auxiliary agent is at least one of polydimethylsiloxane, bentonite or kaolin.

6. The scratch self-repairing epoxy roll material according to any one of claims 1-4, wherein, each layer of the epoxy coating of the top layer comprises, in parts by weight, 65-75 parts of epoxy resin matrix, 10-16 parts of toughening agent, 10-15 parts of curing agent containing disulfide bond and amino group and 0.01-0.1 parts of curing accelerator; and / or, each layer of the epoxy coating of the middle layer comprises, in parts by weight, 40-50 parts of epoxy resin matrix, 4-8 parts of toughening agent, 5-10 parts of curing agent containing disulfide bond and amino group and 0.01-0.1 parts of curing accelerator; and / or, each layer of the epoxy coating of the bottom layer comprises, in parts by weight, 25-30 parts of epoxy resin matrix, 3-6 parts of toughening agent, 3-5 parts of curing agent containing disulfide bond and amino group and 0.01-0.1 parts of curing accelerator.

7. The scratch self-repairing epoxy roll material according to claim 5, wherein, each layer of the epoxy coating of the top layer comprises, in parts by weight, 65-75 parts of epoxy resin matrix, 10-16 parts of toughening agent, 10-15 parts of curing agent containing disulfide bond and amino group, 0.01-0.1 parts of curing accelerator, 1-5 parts of filler and 6-7 parts of auxiliary agent; and / or, each layer of the epoxy coating of the middle layer comprises, in parts by weight, 40-50 parts of epoxy resin matrix, 4-8 parts of toughening agent, 5-10 parts of curing agent containing disulfide bond and amino group, 0.01-0.1 parts of curing accelerator, 30-40 parts of filler, 2-3 parts of auxiliary agent and 7-8 parts of color paste; And / or, the epoxy coating of each layer of the bottom layer comprises, in parts by weight: 25~30 parts of epoxy resin matrix, 3~6 parts of toughening agent, 3~5 parts of curing agent containing disulfide bond and amino group, 0.01~0.1 parts of curing accelerator, 50~60 parts of filler, 3~5 parts of auxiliary agent and 3~4 parts of color paste.

8. A method for preparing the scratch self-repairing epoxy roll material according to any one of claims 1 to 7, characterized by, Comprise: S1, the surface layer is formed by heat curing of the epoxy coating; S2, coating the epoxy coating on the surface layer of S1, and / or superimposing the fiber reinforced layer, forming the middle layer on the surface layer after heat curing; S3, coating the epoxy coating on the middle layer of S2, and / or superimposing the fiber reinforced layer, forming the bottom layer on the middle layer after heat curing, obtaining the scratch self-repairing type epoxy roll.

9. The production method according to claim 8, wherein In S1~S3, the temperature of heat curing is 85~135℃, and the time of heat curing is 30~50 min.

10. A method for repairing a scratch self-repairing epoxy sheeting as claimed in any one of claims 1 to 7, characterized by, Comprise: The scratch self-repairing type epoxy roll with scratches is heated at 75~85℃ for 20~40 min, so that the chain segment of the scratch area migrates, rearranges and realizes interface healing.

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