High abrasion resistant oil based fillerless adhesive coating and method of making same

Abstract

The application belongs to the technical field of oil paint, and particularly relates to a high-wear-resistance oil paint without filler and adhesive coating and a preparation method thereof. The oil paint is composed of component A and component B. The component A comprises bisphenol A type epoxy resin E-51, bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester type polyurethane resin, bisphenol A type phenolic resin, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl ether oxypropyl trimethoxysilane, propylene glycol methyl ether acetate, n-butyl acetate, cyclohexanone, a leveling agent and a defoaming agent. The component B comprises a polyamide curing agent, isophorone diamine, polyether amine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl) phenol. The application constructs a continuous and dense cross-linked coating film through an epoxy resin, a polyurethane flexible chain segment, a phenolic resin, a reactive glycidyl ether, a silane coupling component and a composite amine curing system.

Description

Technical Field

[0001] This invention belongs to the field of oil-based coatings technology, specifically relating to a high-abrasion-resistant oil-based filler-free adhesive coating and its preparation method. Background Technology

[0002] High abrasion-resistant adhesive coatings are widely used for bonding, protection, and abrasion resistance on the surfaces of metals, wood, plastics, composite materials, and building substrates. Existing oil-based adhesive coatings typically use epoxy resins, polyurethane resins, and acrylic resins as the main film-forming substances. Among them, epoxy resins have good adhesion, chemical resistance, and mechanical strength, but after curing, the coating film has a high crosslinking density, which easily leads to problems such as high brittleness, insufficient impact resistance, and easy cracking or peeling after long-term abrasion. Polyurethane resins have good flexibility, abrasion resistance, and elastic recovery ability, but when directly compounded with high epoxy value epoxy resins, they are prone to insufficient compatibility, microphase separation, or decreased film continuity due to differences in polarity, molecular structure, and curing behavior, thus affecting the overall abrasion resistance and adhesive performance of the coating.

[0003] To improve the wear resistance of coatings, existing technologies often employ the addition of inorganic fillers or wear-resistant powders such as heavy calcium carbonate, talc, and barium sulfate to enhance coating hardness and abrasion resistance. However, while the addition of fillers can improve coating surface hardness or reduce costs to some extent, it can also easily lead to problems such as increased system viscosity, difficulty in dispersion, storage sedimentation, decreased leveling properties during application, and increased surface defects in the coating film. For adhesive coatings, a high content of inert mineral fillers may also reduce the effective contact area between the resin and the substrate, weakening interfacial wetting and adhesion, causing the coating to experience decreased adhesion, cohesive failure, or interfacial peeling during bending, impact, friction, or long-term service.

[0004] Therefore, without relying on traditional inert mineral fillers or conventional incremental fillers, how to make oil-based adhesive coatings simultaneously possess high abrasion resistance, adhesion, flexibility, and application stability through resin compatibility design, reactive crosslinking component regulation, and synergistic composite curing system remains an important problem to be solved in the formulation development of this type of coating. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-abrasion-resistant oil-based filler-free adhesive coating and its preparation method. This invention solves the problems of existing high-abrasion-resistant oil-based adhesive coatings relying on traditional inert mineral fillers for reinforcement, which easily leads to dispersion and sedimentation, decreased leveling, increased interface defects, and impaired adhesive properties. Simultaneously, it improves upon the issues of epoxy resin becoming brittle when cured alone and the insufficient compatibility between polyurethane resin and epoxy systems when directly compounded, enabling the coating to maintain good abrasion resistance, adhesion, and film continuity even without traditional fillers.

[0006] The technical effects described in this invention are achieved through the following technical solution: a high-wear-resistant oil-based filler-free adhesive coating, which is composed of component A and component B; Component A, by weight, comprises the following raw materials: 70-85 parts of bisphenol A type epoxy resin E-51, 8-18 parts of bisphenol A type epoxy resin E-44, 12-25 parts of hydroxyl-terminated polyester polyurethane resin, 3-8 parts of bisphenol A type phenolic resin, 4-8 parts of 1,6-hexanediol diglycidyl ether, 2-5 parts of trimethylolpropane triglycidyl ether, 1-2.5 parts of 3-glycidyl etheroxypropyltrimethoxysilane, 8-15 parts of propylene glycol methyl ether acetate, 8-16 parts of n-butyl acetate, 3-8 parts of cyclohexanone, 0.2-0.5 parts of leveling agent, and 0.1-0.3 parts of defoamer; Component B, by mass, comprises the following raw materials: 32-45 parts polyamide curing agent, 5-9 parts isophorone diamine, 2-6 parts polyetheramine D-230, 4-8 parts benzyl alcohol, 4-10 parts propylene glycol methyl ether acetate and 0.2-0.6 parts 2,4,6-tris(dimethylaminomethyl)phenol; Furthermore, component A and component B are mixed at a mass ratio of 100:40-45 to form an oil-based filler-free adhesive coating. Preferably, in one specific embodiment, the hydroxyl-terminated polyester polyurethane resin is prepared by conventional polyurethane prepolymerization reaction, comprising: adding adipic acid-1,4-butanediol polyester diol to a reaction vessel, dehydrating it at 100-110°C under vacuum for 1-2 hours, cooling it to 70-80°C, adding isophorone diisocyanate and propylene glycol methyl ether acetate, stirring evenly, adding dibutyltin dilaurate as a catalyst, and reacting at 75-85°C for 2-4 hours; during the reaction, controlling the molar ratio of isocyanate groups to hydroxyl groups to be 0.7-0.9:1 to ensure that hydroxyl groups are in excess in the system, thereby obtaining the hydroxyl-terminated polyester polyurethane resin; The adipic acid-1,4-butanediol polyester diol has a number average molecular weight of 1000-2000 and a hydroxyl value of 56-112 mgKOH / g; the amount of isophorone diisocyanate added is calculated according to the molar ratio of isocyanate groups to hydroxyl groups of 0.7-0.9:1; the amount of dibutyltin dilaurate is 0.04-0.06% of the total mass of adipic acid-1,4-butanediol polyester diol and isophorone diisocyanate; propylene glycol methyl ether acetate is used to adjust the viscosity and final solid content of the reaction system, and after the reaction, the solid content is adjusted to 60-75% with propylene glycol methyl ether acetate; a hydroxyl-terminated polyester polyurethane resin with a hydroxyl value of 50-80 mgKOH / g is obtained; It should be understood that the hydroxyl-terminated polyester polyurethane resin can also be a commercially available product that meets the above requirements for hydroxyl value, solid content and solvent compatibility.

[0007] Preferably, the leveling agent is selected from one or more of the following: methyl methacrylate-butyl acrylate copolymer, methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, and butyl acrylate-isooctyl acrylate copolymer. Preferably, the defoamer is selected from one or more of polyether-modified polydimethylsiloxane, polyether-polysiloxane copolymer, and polyoxyethylene-polyoxypropylene-modified polydimethylsiloxane; Preferably, the polyamide curing agent is one of polyamide 650, polyamide 651, and polyamide 300; Wherein, the filler-free in this invention means that the coating does not contain any additional traditional inert mineral fillers or conventional incremental fillers such as heavy calcium carbonate, talc, or barium sulfate; the filler-free does not exclude functional components necessary for film formation, curing, leveling, or application performance, such as resins, reactive diluents, silane coupling agents, leveling agents, defoamers, curing agents, and oil-based solvents. Another aspect of the present invention provides a method for preparing a high-abrasion-resistant oil-based filler-free adhesive coating, specifically comprising the following steps: S1: Add bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin, bisphenol A type phenolic resin, propylene glycol methyl ether acetate and cyclohexanone to a mixing container, stir until the bisphenol A type phenolic resin is fully dissolved, and the bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin and bisphenol A type phenolic resin form a uniform compatible resin mother liquor; S2: Add bisphenol A type epoxy resin E-51, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl etheroxypropyltrimethoxysilane, n-butyl acetate, the remaining propylene glycol methyl ether acetate and the remaining cyclohexanone to the compatibility resin mother liquor obtained in step S1, stir evenly to obtain component A resin base; S3: Add leveling agent and defoamer to the resin base material A obtained in step S2, stir evenly and filter to obtain component A; S4: By weight, the polyamide curing agent, isophorone diamine, polyetheramine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl)phenol are mixed evenly to obtain component B; S5: Mix component A obtained in step S3 and component B obtained in step S4 according to the mass ratio, stir evenly, and let stand for 10-30 minutes to obtain an oil-based filler-free adhesive coating. Preferably, in step S1, the amount of propylene glycol methyl ether acetate is 60-65% of the total amount of propylene glycol methyl ether acetate; the amount of cyclohexanone is 60-65% of the total amount of cyclohexanone. Preferably, in step S1, the stirring temperature is 55–65°C; Preferably, in step S3, the filtration is performed using a 100-200 mesh filter. In step S4, the 2,4,6-tris(dimethylaminomethyl)phenol is used as an epoxy curing accelerator. In the above preparation process, no additional traditional inert mineral fillers or conventional additives such as heavy calcium carbonate, talc, or barium sulfate are added. The abrasion resistance of the high-abrasion-resistant oil-based filler-free adhesive coating is mainly provided by the continuous cross-linked coating film formed by the synergistic effect of bisphenol A type epoxy resin E-51, bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin, bisphenol A type phenolic resin, reactive glycidyl ether component, silane coupling component, and composite amine curing system.

[0008] The beneficial effects of this invention are as follows: This invention utilizes the synergistic effect of epoxy resin, polyurethane flexible segments, phenolic resin, reactive glycidyl ether component, silane coupling component and composite amine curing system to construct a continuous and dense cross-linked adhesive coating film, enabling the coating to maintain high wear resistance, adhesion, flexibility and construction stability even without traditional fillers.

[0009] Specifically, bisphenol A type epoxy resin E-51, as the main film-forming resin, can provide high coating hardness, cohesive strength, chemical resistance, and substrate adhesion. However, after curing alone, it is prone to brittleness and insufficient impact resistance due to its high crosslinking density. This invention further introduces bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin, and bisphenol A type phenolic oxy resin, preferentially forming a compatibility resin mother liquor. E-44 and E-51 have similar bisphenol A epoxy structures and can serve as compatibility bridging components in the epoxy continuous phase; the hydroxyl-terminated polyester polyurethane resin can introduce flexible polyurethane segments, improving the coating's toughness, elastic recovery, and wear resistance; the bisphenol A type phenolic oxy resin has a high molecular weight and strong polarity, which can improve the cohesive strength of the resin system and its wetting and adhesion to the substrate through molecular chain entanglement, hydrogen bonding, and polar wetting. After the above three components are pre-formed into a compatible resin masterbatch, it is beneficial to improve the dispersion state of the polyurethane flexible chain segments in the epoxy resin system, reduce the microphase separation that may occur from direct mixing, and make the coating film form a more continuous and uniform resin network after curing.

[0010] In this invention, 1,6-hexanediol diglycidyl ether and trimethylolpropane triglycidyl ether together constitute a reactive glycidyl ether conditioning system. 1,6-hexanediol diglycidyl ether possesses flexible aliphatic segments and biepoxide reactive groups, which on the one hand can reduce the system viscosity and improve the leveling properties during application; on the other hand, it can participate in the amine curing reaction and embed itself into the crosslinking network, thereby alleviating the internal stress concentration after the pure epoxy system has cured. Trimethylolpropane triglycidyl ether has high functionality, which can increase the crosslinking density and surface hardness of the cured network. The combined use of these two components ensures that the coating film has sufficient crosslinking strength and abrasion resistance without becoming significantly brittle due to simply increasing the crosslinking density, thus achieving a balance between hardness, toughness, and abrasion resistance.

[0011] This invention further employs 3-glycidyl etheroxypropyltrimethoxysilane as an interfacial coupling and network densification component. The epoxy groups in this component can participate in the epoxy-amine curing reaction, while the silane groups facilitate the formation of strong interfacial interactions with polar substrates such as metals, glass, ceramics, and concrete. Furthermore, it can introduce certain silicon-oxygen structures into the coating film, thereby improving the interfacial adhesion and film density between the coating and the substrate. This invention enhances interfacial stability through chemical coupling and resin network reinforcement, which helps reduce the risk of interfacial delamination and localized wear propagation under friction, impact, or bending conditions.

[0012] Regarding the curing system, this invention employs a combination of a dimer fatty acid-polyethylene polyamine condensation polyamide curing agent, isophorone diamine, polyetheramine D-230, and 2,4,6-tris(dimethylaminomethyl)phenol. The polyamide curing agent imparts good flexibility, adhesion, and impact resistance to the coating film; isophorone diamine helps improve the hardness, heat resistance, and abrasion resistance of the cured network; polyetheramine D-230 introduces moderately flexible segments to alleviate curing shrinkage and internal stress; and 2,4,6-tris(dimethylaminomethyl)phenol acts as a curing accelerator, which helps improve the curing integrity of the epoxy system. This composite amine curing system avoids the problems of insufficient hardness in single polyamide curing systems or excessive brittleness in single alicyclic amine curing systems, achieving a good balance between adhesive strength, abrasion resistance, and flexibility in the coating.

[0013] Furthermore, the "filler-free" aspect of this invention refers to the absence of additional traditional inert mineral fillers such as heavy calcium carbonate, talc, and barium sulfate, or conventional incremental fillers. Under conditions free of traditional inert mineral fillers or conventional incremental fillers, the wear resistance, adhesion, and film stability of the coating are primarily provided by a continuous resin network synergistically formed by bisphenol A type epoxy resin E-51, bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin, bisphenol A type phenolic resin, reactive glycidyl ether component, 3-glycidyl etheroxypropyltrimethoxysilane, and a complex amine curing system. The results of the examples and comparative examples demonstrate that, within the formulation system free of traditional inert mineral fillers or conventional incremental fillers, the aforementioned resin compatibility structure, interfacial coupling structure, and composite curing system have a significant impact on the coating's wear resistance, adhesion, and storage stability. Attached Figure Description

[0014] Figure 1 The figures show the results of coating wear mass loss after curing of the coatings in Examples 1-3 and Comparative Examples 1-6; Figure 2 The graph shows the adhesion retention rate of the coatings before and after wear after curing in Examples 1 and Comparative Examples 3, 4, and 6. Figure 3 The images shown are FTIR infrared spectra of the coating before and after curing in Example 1. Detailed Implementation

[0015] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the raw materials involved in the present invention are all purchased through conventional commercial channels. Experimental methods without specific conditions are conventional methods and conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

[0016] Example 1: This example provides a high abrasion resistance oil-based filler-free adhesive coating, which is composed of component A and component B mixed in a mass ratio of 100:43; Component A, by weight, consists of the following raw materials: 78 parts bisphenol A type epoxy resin E-51, 13 parts bisphenol A type epoxy resin E-44, 18 parts hydroxyl-terminated polyester polyurethane resin, 5.5 parts bisphenol A type phenolic resin, 6 parts 1,6-hexanediol diglycidyl ether, 3.5 parts trimethylolpropane triglycidyl ether, 1.8 parts 3-glycidyl etheroxypropyltrimethoxysilane, 12 parts propylene glycol methyl ether acetate, 12 parts n-butyl acetate, 5.5 parts cyclohexanone, 0.35 parts leveling agent, and 0.2 parts defoamer; Component B, by weight, consists of the following raw materials: 38 parts polyamide curing agent, 7 parts isophorone diamine, 4 parts polyetheramine D-230, 6 parts benzyl alcohol, 7 parts propylene glycol methyl ether acetate, and 0.4 parts 2,4,6-tris(dimethylaminomethyl)phenol. The preparation method of this embodiment includes the following steps: (1): Adipic acid-1,4-butanediol polyester diol with a number average molecular weight of 1500 and a hydroxyl value of 75 mgKOH / g was selected and added to a reaction vessel. It was dehydrated at 105°C under vacuum for 1.5 h. After cooling to 75°C, isophorone diisocyanate was added according to the molar ratio of isocyanate group to hydroxyl group of 0.8:1. Propylene glycol methyl ether acetate was added as a reaction diluent. After stirring evenly, dibutyltin dilaurate was added as a catalyst. The amount of dibutyltin dilaurate was 0.05% of the total mass of adipic acid-1,4-butanediol polyester diol and isophorone diisocyanate. Then, the reaction was carried out at 80°C for 3 h to make the hydroxyl group in the system in excess, and hydroxyl-terminated polyester polyurethane resin was obtained. After the reaction was completed, the resin solid content was adjusted to 68% with propylene glycol methyl ether acetate to obtain hydroxyl-terminated polyester polyurethane resin with a hydroxyl value of 65 mgKOH / g. (2): Add the above-mentioned amount of bisphenol A type epoxy resin E-44, the hydroxyl-terminated polyester polyurethane resin obtained in step (1), bisphenol A type phenolic resin, 7.2 parts of propylene glycol methyl ether acetate and 3.5 parts of cyclohexanone into a mixing container, and stir at 60°C until the bisphenol A type phenolic resin is fully dissolved to form a uniform compatibility resin mother liquor. (3): Add the formulated amounts of bisphenol A type epoxy resin E-51, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl etheroxypropyltrimethoxysilane, n-butyl acetate, the remaining propylene glycol methyl ether acetate and the remaining cyclohexanone to the compatible resin mother liquor obtained in step (2), stir evenly, and obtain component A resin base material; (4): Add the formulated amount of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer and polyether modified polydimethylsiloxane to the resin base of component A obtained in step (3), stir evenly, and then filter with a 150-mesh filter to obtain component A; (5): Based on the mass fraction of the formulation, polyamide 650, isophorone diamine, polyetheramine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl)phenol are mixed evenly to obtain component B; (6): Mix component A obtained in step (4) and component B obtained in step (5) at a mass ratio of 100:43, stir evenly, and let stand for 20 minutes to obtain a high wear-resistant oil-based filler-free adhesive coating.

[0017] Example 2: This example provides a high abrasion resistance oil-based filler-free adhesive coating, which is composed of component A and component B mixed in a mass ratio of 100:40; Component A, by weight, consists of the following raw materials: 85 parts bisphenol A type epoxy resin E-51, 8 parts bisphenol A type epoxy resin E-44, 12 parts hydroxyl-terminated polyester polyurethane resin, 8 parts bisphenol A type phenolic resin, 4 parts 1,6-hexanediol diglycidyl ether, 5 parts trimethylolpropane triglycidyl ether, 1 part 3-glycidyl etheroxypropyltrimethoxysilane, 15 parts propylene glycol methyl ether acetate, 8 parts n-butyl acetate, 8 parts cyclohexanone, 0.5 parts leveling agent, and 0.1 parts defoamer; Component B, by weight, consists of the following raw materials: 45 parts polyamide curing agent, 5 parts isophorone diamine, 6 parts polyetheramine D-230, 4 parts benzyl alcohol, 10 parts propylene glycol methyl ether acetate, and 0.2 parts 2,4,6-tris(dimethylaminomethyl)phenol. The preparation method of this embodiment includes the following steps: (1): Adipic acid-1,4-butanediol polyester diol with a number average molecular weight of 1000 and a hydroxyl value of 112 mgKOH / g was selected and added to a reaction vessel. It was dehydrated at 110°C under vacuum for 1 h. After cooling to 70°C, isophorone diisocyanate was added according to the molar ratio of isocyanate group to hydroxyl group of 0.7:1. Propylene glycol methyl ether acetate was added as a reaction diluent. After stirring evenly, dibutyltin dilaurate was added as a catalyst. The amount of dibutyltin dilaurate was 0.04% of the total mass of adipic acid-1,4-butanediol polyester diol and isophorone diisocyanate. Then, the reaction was carried out at 85°C for 2 h to make the hydroxyl group in the system in excess, and hydroxyl-terminated polyester polyurethane resin was obtained. After the reaction was completed, the resin solid content was adjusted to 75% with propylene glycol methyl ether acetate to obtain hydroxyl-terminated polyester polyurethane resin with a hydroxyl value of 80 mgKOH / g. (2): Add the above-mentioned amount of bisphenol A type epoxy resin E-44, the hydroxyl-terminated polyester polyurethane resin obtained in step (1), bisphenol A type phenolic resin, 9 parts of propylene glycol methyl ether acetate and 5.2 parts of cyclohexanone into a mixing container, and stir at 65°C until the bisphenol A type phenolic resin is fully dissolved to form a uniform compatibility resin mother liquor. (3): Add the formulated amounts of bisphenol A type epoxy resin E-51, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl etheroxypropyltrimethoxysilane, n-butyl acetate, the remaining propylene glycol methyl ether acetate and the remaining cyclohexanone to the compatible resin mother liquor obtained in step (2), stir evenly, and obtain component A resin base material; (4): Add the formulated amount of butyl acrylate-isooctyl acrylate copolymer and polyoxyethylene polyoxypropylene modified polydimethylsiloxane to the resin base of component A obtained in step (3), stir evenly, and then filter with a 100-mesh filter to obtain component A. (5): Mix the formulated amounts of polyamide 300, isophorone diamine, polyetheramine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl)phenol evenly to obtain component B; (6): Mix component A obtained in step (4) and component B obtained in step (5) at a mass ratio of 100:40, stir evenly, and let stand for 10 minutes to obtain a high wear-resistant oil-based filler-free adhesive coating.

[0018] Example 3: This example provides a high abrasion resistance oil-based filler-free adhesive coating, which is composed of component A and component B mixed in a mass ratio of 100:45; Component A, by weight, consists of the following raw materials: 70 parts bisphenol A type epoxy resin E-51, 18 parts bisphenol A type epoxy resin E-44, 25 parts hydroxyl-terminated polyester polyurethane resin, 3 parts bisphenol A type phenolic resin, 8 parts 1,6-hexanediol diglycidyl ether, 2 parts trimethylolpropane triglycidyl ether, 2.5 parts 3-glycidyl etheroxypropyltrimethoxysilane, 8 parts propylene glycol methyl ether acetate, 16 parts n-butyl acetate, 3 parts cyclohexanone, 0.2 parts leveling agent, and 0.3 parts defoamer; Component B, by weight, consists of the following raw materials: 32 parts polyamide curing agent, 9 parts isophorone diamine, 2 parts polyetheramine D-230, 8 parts benzyl alcohol, 4 parts propylene glycol methyl ether acetate, and 0.6 parts 2,4,6-tris(dimethylaminomethyl)phenol. The preparation method of this embodiment includes the following steps: (1): Adipic acid-1,4-butanediol polyester diol with a number average molecular weight of 2000 and a hydroxyl value of 56 mg KOH / g was selected. It was dehydrated at 100℃ under vacuum for 2 h. After cooling to 80℃, isophorone diisocyanate was added according to the molar ratio of isocyanate group to hydroxyl group of 0.9:1. Propylene glycol methyl ether acetate was added as a reaction diluent. After stirring evenly, dibutyltin dilaurate was added as a catalyst. The amount of dibutyltin dilaurate was 0.06% of the total mass of adipic acid-1,4-butanediol polyester diol and isophorone diisocyanate. Then, it was reacted at 75℃ for 4 h to make the hydroxyl group in the system in excess, and hydroxyl-terminated polyester polyurethane resin was obtained. After the reaction was completed, the resin solid content was adjusted to 60% with propylene glycol methyl ether acetate to obtain hydroxyl-terminated polyester polyurethane resin with a hydroxyl value of 50 mg KOH / g. (2): Add the above-mentioned amount of bisphenol A type epoxy resin E-44, the hydroxyl-terminated polyester polyurethane resin obtained in step (1), bisphenol A type phenolic resin, 5.2 parts of propylene glycol methyl ether acetate and 1.8 parts of cyclohexanone into a mixing container, and stir at 55°C until the bisphenol A type phenolic resin is fully dissolved to form a uniform compatibility resin mother liquor. (3): Add the formulated amounts of bisphenol A type epoxy resin E-51, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl etheroxypropyltrimethoxysilane, n-butyl acetate, the remaining propylene glycol methyl ether acetate and the remaining cyclohexanone to the compatible resin mother liquor obtained in step (2), stir evenly, and obtain component A resin base material; (4): Add the formulated amounts of methyl methacrylate-butyl acrylate copolymer and polyether-polysiloxane copolymer to the resin base of component A obtained in step (3), stir evenly, and then filter with a 200-mesh filter to obtain component A; (5): Mix the formulated amounts of polyamide 651, isophorone diamine, polyetheramine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl)phenol evenly to obtain component B; (6): Mix component A obtained in step (4) and component B obtained in step (5) at a mass ratio of 100:45, stir evenly, and let stand for 30 minutes to obtain a high wear-resistant oil-based filler-free adhesive coating.

[0019] Comparative Example 1: Compared with Example 1, the only difference is that hydroxyl-terminated polyester polyurethane resin is not added, and it is replaced by an equal amount of bisphenol A type epoxy resin E-51. The amounts of other raw materials and the preparation methods are the same as in Example 1. This is used to verify that the flexible polyurethane segments introduced by the hydroxyl-terminated polyester polyurethane resin play an important role in improving the toughness, impact resistance and wear resistance of the coating film.

[0020] Comparative Example 2: Compared with Example 1, the only difference is that bisphenol A type epoxy resin E-44 is not added, and it is replaced by an equal amount of bisphenol A type epoxy resin E-51. The amounts of other raw materials and the preparation methods are the same as in Example 1. It is used to verify that E-44, as a compatibility bridging component between the epoxy continuous phase and the polyurethane flexible segment, is beneficial to improving the compatibility and film continuity of the resin system.

[0021] Comparative Example 3: Compared with Example 1, the only difference is that bisphenol A type phenolic oxy resin is not added, and it is replaced by an equal amount of bisphenol A type epoxy resin E-51. The amounts of other raw materials and the preparation methods are the same as in Example 1. It is used to verify that phenolic oxy resin improves coating adhesion, peel resistance and structural retention during wear resistance through molecular chain entanglement, polar wetting and cohesive reinforcement.

[0022] Comparative Example 4: Compared with Example 1, the only difference is that 3-glycidyl etheroxypropyltrimethoxysilane is not added, and it is replaced by an equal amount of 1,6-hexanediol diglycidyl ether. The amounts of other raw materials and the preparation methods are the same as in Example 1. It is used to verify that the epoxy and silane groups in KH-560 have a promoting effect on improving the interfacial bonding between the coating and the substrate, the density of the coating film, and the adhesion retention ability after wear resistance.

[0023] Comparative Example 5: Compared with Example 1, the only difference is that all the raw materials in component A are added to the mixing container at one time and stirred at 60°C until the system is homogeneous to obtain component A. The amount of the remaining raw materials and the preparation method are the same as in Example 1. This is used to verify that the pre-formed compatibility resin mother liquor can improve the dispersion compatibility of polyurethane resin, E-44 and phenolic resin in the epoxy system, thereby reducing microphase separation and coating defects caused by simple one-time mixing.

[0024] Comparative Example 6: Compared with Example 1, the only difference is that 15 parts of heavy calcium carbonate were added to component A as a traditional inert mineral filler, that is, heavy calcium carbonate was added to the resin base of component A obtained in step (3). The amount of other raw materials and the preparation method are the same as in Example 1. This is used to verify that after adding traditional inert mineral fillers to the resin system of the present invention, the fillers tend to increase the viscosity and dispersion burden of the system, and may introduce resin-filler interface defects in the coating film, thereby affecting the storage stability, leveling properties, film continuity and adhesion retention ability of the coating after wear.

[0025] Performance Testing: To verify the abrasion resistance, adhesion, film continuity, flexibility, impact resistance, and construction and storage stability of the high abrasion resistance oil-based fillerless adhesive coating of the present invention under conditions without traditional inert mineral fillers, performance tests were conducted on the coatings obtained in Examples 1-3 and Comparative Examples 1-6. Unless otherwise specified, all treatments were applied to the surface of Q235 steel plates that had been sanded, degreased, and dried using the same scraping method, with the dry film thickness controlled at 70±5μm. The coated samples were cured for 7 days at a temperature of 23±2℃ and a relative humidity of 50±5% before testing; three parallel samples were set for each test, and numerical results were expressed as mean ± standard deviation, while graded and appearance results recorded typical performance. During the preparation of test samples, the surface of the Q235 steel plate was first sanded to remove the surface oxide layer and obvious dirt, then wiped with anhydrous ethanol to remove oil, and dried at room temperature before use. During the coating process, all treatments used the same scraping method, the same dry film thickness range, and the same curing conditions to ensure that the test results between different examples and comparative examples were comparable.

[0026] The wear resistance was tested according to the rotating rubber grinding wheel method in GB / T 1768. The cured coating samples (Examples 1-3 and Comparative Examples 1-6) were placed in a standard environment for 24 hours before testing. A CS-10 type grinding wheel was used, with a single wheel load of 1000g, a rotation speed of 60 r / min, and a formal wear cycle of 1000 r. Before testing, the grinding wheel was pre-ground according to the instrument requirements, with 50 pre-ground cycles to ensure a consistent surface condition. The sample mass was weighed using an electronic balance with an accuracy of not less than 0.1 mg before and after testing, and the wear mass loss was calculated based on the mass difference before and after wear.

[0027] The coating's resistance to peeling was tested using a cross-cut test according to GB / T 9286. An appropriate cross-cut spacing was selected based on the coating thickness; in this test, the spacing was 2 mm. After cross-cutting, the cut surfaces were cleaned with a soft brush, and then standard tape was applied and peeled off. The degree of detachment of the coating (Examples 1-3 and Comparative Examples 1-6) from the substrate was observed and evaluated according to the standard grade. Pull-off adhesion was tested according to GB / T 5210. A pull-off head was bonded to the coating surface with a two-component epoxy adhesive. After the adhesive had fully cured, it was pulled off in a direction perpendicular to the coating surface, and the pull-off adhesion was recorded in MPa. The failure mode was also recorded, including coating cohesive failure, coating / substrate interface failure, adhesive failure, or mixed failure. When the failure mainly occurred within the coating, or exhibited mixed failure with a low proportion of interface failure, it indicated that the coating and substrate had good interfacial bonding stability.

[0028] To further evaluate the interface retention ability of the coatings after abrasion, the coatings obtained in Examples 1, 3, 4, and 6 were subjected to pull-off adhesion tests after abrasion resistance tests, and the results were compared with the pull-off adhesion before abrasion. The pull-off adhesion retention rate was calculated using the following formula: Pull-off adhesion retention rate / % = Pull-off adhesion after abrasion / Pull-off adhesion before abrasion × 100%.

[0029] Pencil hardness was tested according to GB / T 6739 to evaluate the coating surface's resistance to scratches. Testing was conducted sequentially from low to high hardness, with the highest pencil hardness (Examples 1-3 and Comparative Examples 1-6) showing no significant scratches or damage being taken as the test result. Flexibility was tested according to GB / T 1731, with the minimum shaft diameter at which the coating does not crack, peel, or show significant failure after bending being used as the evaluation index. Impact resistance was tested according to GB / T 1732, with the maximum impact height at which the coating does not crack, peel, or show significant damage after impact being used as the evaluation index.

[0030] To evaluate the storage stability and resin system compatibility of component A, the components A obtained in Examples 1-3 and Comparative Examples 1-6 were respectively placed into clean, dry 0.4L covered metal coating containers, with a filling volume of 80% of the container volume. After sealing, they were placed at 50±2℃ for 7 days. After removal, the temperature was restored to 23±2℃, and the samples were observed to see if there was obvious stratification, sedimentation, flocculation, gelation, skinning, or non-redispersibility. After slight stirring, the system was observed to see if it could return to a homogeneous state. At the same time, the viscosity before and after storage was measured, and the viscosity change rate was calculated according to the following formula: Viscosity change rate / % = (Viscosity after storage - Viscosity before storage) / Viscosity before storage × 100%.

[0031] The pot life was tested according to GB / T 31416. Components A and B of Examples 1-3 and Comparative Examples 1-6 were mixed at the specified mass ratio, and the mixing time was immediately started. After thorough mixing, the mixture was placed at 25±2℃, and the viscosity of the mixture was measured using a rotational viscometer. The same type of viscometer, rotor, and rotational speed were used for all treatments in the test. Under one specific test condition, an NDJ-1 type rotational viscometer was used, with a rotor speed of 60 r / min. The viscosity measured 5 minutes after the mixture of components A and B was thoroughly mixed was taken as the initial viscosity. The time elapsed until the system viscosity increased to twice the initial viscosity was taken as the end of the pot life.

[0032] Fourier transform infrared spectroscopy was used to test the samples of Example 1 before and after curing. The sample before curing was a mixture of components A and B in Example 1 at a mass ratio of 100:43, and samples were taken within 5 minutes for ATR-FTIR testing. The sample after curing was a cured coating obtained by applying the same batch of mixed coatings to form a film and curing it for 7 days at 23±2℃ and 50±5% relative humidity.

[0033] The coatings obtained in Examples 1-3 and Comparative Examples 1-6 were applied to the surface of Q235 steel plates under the same conditions and allowed to level and cure naturally at 23±2℃ and 50±5% relative humidity. After curing, the surface of the coating was observed to see if it was smooth and uniform, and whether there were obvious scratches, pinholes, bubbles, orange peel, haze, or local loss of gloss.

[0034] The test results are shown in Tables 1-3 and 3 respectively. Figures 1-3 Table 1 shows the test results of pencil hardness, flexibility, and impact resistance of the coatings obtained in Examples 1-3 and Comparative Examples 1-6. Table 2 shows the test results of cross-cut adhesion rating, pull-off adhesion before abrasion, and pull-off failure mode of the coatings obtained in Examples 1-3 and Comparative Examples 1-6. Table 3 shows the test results of storage stability, viscosity change rate, pot life after mixing, and coating appearance of component A obtained in Examples 1-3 and Comparative Examples 1-6. Figure 1 A comparison chart showing the wear and mass loss of coatings with different treatments. Figure 2The chart shows the comparison of adhesion retention rates before and after wear for Examples 1, 3, 4, and 6. Figure 3 The images are FTIR infrared spectra before and after curing in Example 1.

[0035] Table 1. Results of hardness, flexibility, and impact resistance of different treated coatings in the examples and comparative samples.

[0036] Table 2. Cross-cutting grade, pull-off adhesion before abrasion, and pull-off failure modes of different treated coatings in the examples and comparative samples.

[0037] Table 3. Storage stability, viscosity change rate, pot life, and coating appearance of component A under different treatments in the examples and comparative samples.

[0038] From Table 1 and Figure 1 As can be seen, the wear mass loss of the coatings obtained in Examples 1-3 is lower than that of the comparative examples, while maintaining good hardness, flexibility, and impact resistance. This indicates that the present invention can still achieve good wear resistance and mechanical balance through the resin network itself without the addition of traditional inert mineral fillers. Example 1 exhibits superior overall performance, indicating that the coordination between the rigid epoxy network, the flexible polyurethane segments, the cohesive reinforcement of phenolic resin, the reactive glycidyl ether crosslinking regulation, and the KH-560 interfacial coupling is relatively harmonious under the intermediate ratio. Example 2 leans towards higher hardness and higher crosslinking density, while Example 3 leans towards flexibility and interfacial coupling reinforcement. Although they each have their own emphasis on individual properties, their overall wear resistance and mechanical properties are still better than the comparative examples, indicating that the different ratios defined by the technical solution of the present invention can all obtain relatively stable overall performance.

[0039] In Comparative Example 1, the removal of the hydroxyl-terminated polyester polyurethane resin significantly reduced the coating's flexibility, impact resistance, and abrasion stability. This indicates that the flexible polyurethane segments not only improve coating toughness but also alleviate stress concentration in the rigid epoxy network during friction and impact, reducing the risk of brittle fracture and localized wear propagation. In Comparative Example 2, the removal of E-44 reduced the coating's abrasion resistance and film-forming stability, suggesting that E-44, as an epoxy bridging component with a structure similar to E-51, helps improve the compatibility between the flexible polyurethane segments and the continuous epoxy phase. In Comparative Example 5, although the raw material composition was basically the same as in Example 1, the preparation step of the compatibility resin mother liquor was omitted, resulting in significantly worse abrasion resistance and coating appearance. This indicates that the present invention is not a simple one-time mixing of raw materials but relies on pre-compatibility treatment to form a more uniform resin dispersion. Comparative Example 6, which added heavy calcium carbonate to the resin system of Example 1, showed that although the apparent hardness of the coating was improved, the wear mass loss, flexibility and impact resistance were inferior to those of Example 1. This indicates that the addition of traditional inert mineral fillers cannot replace the wear-resistant enhancement effect of the resin network itself in this invention, and the filler particles may cause local stress concentration and resin-filler interface defects, thereby affecting the structural integrity of the coating during bending, impact and friction.

[0040] From Table 2 and Figure 2 As can be seen, Examples 1-3 all exhibited good resistance to delamination and pull-off adhesion. The failure mode was mainly cohesive failure or a mixed failure mode dominated by cohesive failure, indicating that there is a strong interfacial bond between the coating and the substrate, and it is not easy to preferentially peel off from the substrate interface during the pull-off process. This further illustrates that different ratios defined by the technical solution of the present invention can achieve relatively stable adhesive performance. After removing the phenolic resin in Comparative Example 3, the pull-off adhesion and the pull-off adhesion retention rate after abrasion decreased, indicating that the phenolic resin helps to improve the internal structural strength of the coating and the structural retention ability after abrasion through molecular chain entanglement, polarity, and cohesive reinforcement. After removing KH-560 in Comparative Example 4, the failure mode was more inclined to interfacial failure, and the pull-off adhesion retention rate after abrasion decreased more significantly, indicating that the epoxy and silane groups in KH-560 play an important role in the interfacial coupling between the coating and the substrate and the interfacial stability after abrasion. After adding heavy calcium carbonate, Comparative Example 6 showed that the pull-off adhesion and the pull-off adhesion retention rate after wear were both lower than those in Example 1. The proportion of interface damage in the failure mode increased, indicating that traditional inert mineral fillers occupy part of the continuous resin phase and form a resin-filler interface, reducing the effective wetting and continuous bonding between the resin film-forming components and the metal substrate, thereby weakening the interface retention ability of the coating after wear.

[0041] As shown in Table 3, component A of Examples 1-3 maintained good homogeneity and minimal viscosity change after accelerated storage, with a smooth coating surface. This indicates that pre-forming a compatibility resin mother liquor using E-44, hydroxyl-terminated polyester polyurethane resin, and phenolic resin is beneficial for improving the storage stability and film quality of the oily resin system. Comparative Example 2, lacking the E-44 bridging compatibility component, exhibited slight turbidity and localized stratification after storage. Comparative Example 5, by omitting the compatibility mother liquor step, showed more pronounced turbidity, flocculation, fogging, orange peel, and pinholes, resulting in coating defects. Comparative Example 6, due to the addition of heavy calcium carbonate, showed filler sedimentation and slight agglomeration after storage, increased viscosity change rate, and visible slight orange peel, granular protrusions, and localized fogging on the coating surface. This indicates that the addition of traditional inert mineral fillers increases the difficulty of system dispersion and storage stability control, and can easily adversely affect the continuity of the coating appearance. The pot life results show that Examples 1-3 all have suitable application windows, indicating that the composite amine curing system and the amount of DMP-30 accelerator can achieve a balance between curing reactivity and application time. Example 2 has a relatively longer pot life, while Example 3 has a relatively shorter pot life, mainly due to differences in the proportion of component B and the amount of accelerator. Overall, the coating of this invention, while ensuring post-curing performance, still meets the requirements for application time and leveling film formation in conventional trowel coating.

[0042] Depend on Figure 3 As can be seen from the FTIR spectrum, after curing in Example 1, the wavelength is approximately 900–930 cm⁻¹. -1 The characteristic absorption of epoxy groups in the region was significantly reduced compared to before curing, indicating that the epoxy groups in component A underwent a ring-opening curing reaction under the action of the amine curing agent in component B. (Approximately 3200–3600 cm⁻¹) -1 The hydroxyl-related broad absorption band in the region was enhanced and broadened after curing, which may be related to the increase in hydroxyl groups after epoxy ring opening and the enhanced interaction of polar groups in the system. The bands before and after curing were approximately 1715–1735 cm⁻¹. -1 Carbonyl-related absorption can still be observed in this region. This absorption is mainly related to the ester carbonyl groups contained in the polyester segments of the hydroxyl-terminated polyester polyurethane resin, which are derived from the adipic acid-1,4-butanediol polyester diol structure. This absorption region serves only as an auxiliary characterization of the polyester segment structure in the added hydroxyl-terminated polyester polyurethane resin and is not used to determine the specific absorption peak position of the urethane carbonyl group in the polyurethane structure, nor does it indicate the regeneration of the carbonyl structure during the epoxy-amine curing process. (Approximately 1000–1150 cm⁻¹) -1The region represents the superposition of COC, CO, and silicon-related absorptions. Absorption in this region remains observable before and after curing, accompanied by changes in peak shape or intensity. The presence of 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and 3-glycidyl etheroxypropyltrimethoxysilane in the system can serve as auxiliary characterization of the reactive glycidyl ether component and silane-related structures in the cured coating. The above FTIR results, combined with the results on coating mechanical properties, adhesion properties, and storage stability, indicate that this invention forms a continuously crosslinked, filler-free adhesive coating through an epoxy-amine curing reaction and the synergistic effect of a multi-component resin network.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-abrasion-resistant, oil-based, filler-free adhesive coating, characterized in that, It consists of component A and component B; Component A, by weight, comprises the following raw materials: 70-85 parts of bisphenol A type epoxy resin E-51, 8-18 parts of bisphenol A type epoxy resin E-44, 12-25 parts of hydroxyl-terminated polyester polyurethane resin, 3-8 parts of bisphenol A type phenolic resin, 4-8 parts of 1,6-hexanediol diglycidyl ether, 2-5 parts of trimethylolpropane triglycidyl ether, 1-2.5 parts of 3-glycidyl etheroxypropyltrimethoxysilane, 8-15 parts of propylene glycol methyl ether acetate, 8-16 parts of n-butyl acetate, 3-8 parts of cyclohexanone, 0.2-0.5 parts of leveling agent, and 0.1-0.3 parts of defoamer; Component B, by mass, comprises the following raw materials: 32-45 parts polyamide curing agent, 5-9 parts isophorone diamine, 2-6 parts polyetheramine D-230, 4-8 parts benzyl alcohol, 4-10 parts propylene glycol methyl ether acetate and 0.2-0.6 parts 2,4,6-tris(dimethylaminomethyl)phenol; The mixture of component A and component B at a mass ratio of 100:40-45 constitutes an oil-based filler-free adhesive coating. The hydroxyl-terminated polyester polyurethane resin has a hydroxyl value of 50-80 mgKOH / g and a solid content of 60-75%. The preparation of the high abrasion resistance oil-based filler-free adhesive coating includes the following steps: S1: Add bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin, bisphenol A type phenolic resin, propylene glycol methyl ether acetate and cyclohexanone to a mixing container, stir until the bisphenol A type phenolic resin is fully dissolved, and the bisphenol A type epoxy resin E-44, hydroxyl-terminated polyester polyurethane resin and bisphenol A type phenolic resin form a uniform compatible resin mother liquor; S2: Add bisphenol A type epoxy resin E-51, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 3-glycidyl etheroxypropyltrimethoxysilane, n-butyl acetate, the remaining propylene glycol methyl ether acetate and the remaining cyclohexanone to the compatibility resin mother liquor obtained in step S1, stir evenly to obtain component A resin base; S3: Add leveling agent and defoamer to the resin base material A obtained in step S2, stir evenly and filter to obtain component A; S4: By weight, the polyamide curing agent, isophorone diamine, polyetheramine D-230, benzyl alcohol, propylene glycol methyl ether acetate and 2,4,6-tris(dimethylaminomethyl)phenol are mixed evenly to obtain component B; S5: Mix component A obtained in step S3 and component B obtained in step S4 according to the mass ratio, stir evenly, and let stand to mature to obtain an oil-based filler-free adhesive coating. In step S1, the stirring temperature is 55-65°C.

2. The high abrasion resistance oil-based filler-free adhesive coating according to claim 1, characterized in that, The leveling agent is selected from one or more of the following: methyl methacrylate-butyl acrylate copolymer, methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, and butyl acrylate-isooctyl acrylate copolymer.

3. The high abrasion resistance oil-based filler-free adhesive coating according to claim 1, characterized in that, The defoamer is selected from one or more of polyether-modified polydimethylsiloxane, polyether-polysiloxane copolymer, and polyoxyethylene-polyoxypropylene-modified polydimethylsiloxane.

4. The high abrasion resistance oil-based filler-free adhesive coating according to claim 1, characterized in that, The polyamide curing agent is one of polyamide 650, polyamide 651 and polyamide 300.

5. The high abrasion resistance oil-based filler-free adhesive coating according to claim 1, characterized in that, In step S1, the amount of propylene glycol methyl ether acetate is 60-65% of the total amount of propylene glycol methyl ether acetate; the amount of cyclohexanone is 60-65% of the total amount of cyclohexanone.

6. The high abrasion resistance oil-based filler-free adhesive coating according to claim 1, characterized in that, In step S3, the filtration is performed using a 100-200 mesh filter.

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