Printing scratch-resistant composition as well as preparation method and application thereof

Abstract

The invention discloses a printing scratch-resistant composition as well as a preparation method and application thereof, and the printing scratch-resistant composition is prepared from the following components: polycaprolactone glycol modified polyester polyol resin, a compound solvent, organic treatment matting powder, an organic silicon hand feeling aid, polyurethane elastic powder, a compound drier and the like. According to the formula, caprolactone glycol modified polyester polyol resin is used as a basis, and is matched with a compound drier compounded by a modified polyurethane polymer and organic bismuth to replace a traditional harmful organic tin drier, so that the harm of a tin element to a human body and the environment is eliminated, and the drying efficiency and the construction life of a coating are effectively balanced; the construction life is prolonged to 4 h or above, the window period of the spraying process is remarkably prolonged, the problem that the construction life is short under a traditional high-viscosity system is solved, and the method is suitable for batch silk-screen production.

Description

Technical Field

[0001] This invention relates to the field of matte oil technology, specifically to a printing scratch-resistant composition, its preparation method, and its application. Background Technology

[0002] In the surface treatment of high-end electronic products (such as laptops, mobile phone casings, and speaker panels), matte coatings are highly favored for their elegant appearance and comfortable feel. These coatings, due to the resin systems they use, almost always require a thick layer of 20-30 μm applied via spraying to achieve the desired scratch and abrasion resistance. Thick coatings require longer baking times and higher temperatures, and incomplete drying can easily lead to film sticking. Therefore, driers are generally added to the formulation to accelerate the reaction. Currently, the driers used in the market are generally organotin driers. These driers have good drying effects but short application life (solidifying in 1-2 hours), especially in high-viscosity systems, where the application life generally does not exceed 1 hour. It is difficult to balance drying effect and application life. Furthermore, these driers often rely on a single isoflurane solvent system (VOC content approximately 240 g / L), and solvent evaporation during spraying can easily lead to high VOC emissions. In addition, organotin driers contain tin, an element harmful to human health and the environment. Therefore, there is an urgent need to provide a new printable scratch-resistant composition and preparation method to solve the above-mentioned technical bottlenecks. Summary of the Invention

[0003] To address the aforementioned problems, one objective of this invention is to provide a printable scratch-resistant composition, comprising, by weight, 30-58 parts of polycaprolactone diol-modified polyester polyol resin, 15-25 parts of compounded solvent, 5-9 parts of organic matting agent, 1-3 parts of silicone hand-feel additive, 1-3 parts of polyurethane elastic powder, 0.2-3 parts of compounded drying agent, 0.1-0.5 parts of organophosphate ester delay agent, 1-3 parts of polymeric dispersant, 0.3-0.7 parts of silicone leveling agent, 0.4-0.8 parts of polyether defoamer, and 18-22 parts of colorant; wherein, Polycaprolactone diol modified polyester polyol resin has a hydroxyl value of 50~80mgKOH / g, an acid value ≤2mgKOH / g, and a grafting rate of 15~25%. The compound solvent is a mixture of divalent ester and isoflurone in a mass ratio of 2-4:1. The compound drying agent is composed of modified polyurethane polymer and organic bismuth in a mass ratio of 1~2:1.

[0004] Preferably, the organically treated matting agent is polyamide wax-coated fumed silica with a particle size of 2-3 μm. This matting agent has good compatibility with polycaprolactone diol-modified polyester polyol resin, avoiding the rough feel caused by matting agent agglomeration. The particle size of 2-3 μm ensures uniform distribution on the coating surface, forming a micro-rough structure to achieve a fully matte effect.

[0005] Preferably, the organic bismuth is bismuth isooctanoate.

[0006] Preferably, the polyurethane elastic powder is a cross-linked polyurethane color bead with a particle size of 5~8μm, selected from Daihatsu Seika 5070D. This polyurethane elastic powder can complement organically treated matte powder, rebounds after being compressed, can repair minor scratches (self-healing time ≤30s), and fills the gaps in the matte powder to avoid a dry feel.

[0007] Preferably, the organosilicon feel aid is polyether-modified polydimethylsiloxane.

[0008] Preferably, the organophosphate delay agent is triphenyl phosphate or triphenyl phosphite.

[0009] Preferably, the polymeric dispersant is selected from at least one of Lubrizol Solsperse 32000 and Solsperse 35000.

[0010] Preferably, the silicone leveling agent is hydroxyl-terminated polydimethylsiloxane, and the polyether defoamer is polyoxyethylene polyoxypropylene propylene glycol ether.

[0011] Another objective of this application is to provide a method for preparing a printable scratch-resistant composition as follows: Preparation of caprolactone diol modified polyester polyol resin: Under nitrogen protection, 80-90 parts of polyester polyol resin with a number average molecular weight of 1500-2000 g / mol were heated to 120-130℃, 10-20 parts of polycaprolactone diol with a number average molecular weight of 1000-2000 g / mol and 0.01-0.05 parts of organic bismuth catalyst were added, the temperature was slowly raised to 140-160℃, and the reaction was maintained for 2-4 hours. When the hydroxyl value was 50-80 mgKOH / g, the acid value was ≤2 mgKOH / g, and the grafting rate was 15-25%, the reaction was stopped, and the material was cooled and discharged. Preparation of compound drying agent: 45-55 parts by weight of polycaprolactone diol and 24-28 parts by weight of isophorone diisocyanate were added to a reaction vessel under nitrogen protection. The mixture was heated to 80-90℃ and stirred at 300-500 rpm for 2-3 hours to obtain the terminal isocyanate prepolymer. Then, 5-9 parts by weight of 1,4-butanediol were added, and the reaction was continued at 85-95℃ for 1-2 hours. After the reaction was completed, the temperature was lowered to 55-65℃, and 3-4 parts by weight of... The n-butanol end-capping reaction is carried out for 0.5-1.5 hours; then 11-15 parts of hydroxyethyl acrylate are added for end-capping modification, and the reaction is carried out at 70-80℃ for 1-2 hours to obtain a modified polyurethane polymer with a number average molecular weight of about 8000-12000 and a viscosity of 8000-12000 mPa·s at 25℃. The modified polyurethane polymer is then mixed with organic bismuth at a mass ratio of 1-2:1 under light-protected conditions at 20-30℃ to obtain a compound drying agent. Preparation of organic matting powder: Heat 40-60 parts by weight of polyamide wax to 110-130℃ until it is completely melted, then add 30-40 parts of fumed silica under high-speed stirring at 1000-2000 rpm to fully wet and uniformly coat the surface of the fumed silica with the liquid polyamide wax. Stop heating, cool and solidify, then crush and sieve the material to obtain the above organic matting powder. Premixing and grinding: Add 1-3 parts of polymeric dispersant and 18-22 parts of color powder to a container, pre-disperse at 2000-3000 r / min for 5-15 min, then add 30-58 parts of polycaprolactone diol modified polyester polyol resin, 15-25 parts of compound solvent, and 1-3 parts of organosilicon hand feel additive, stir at 800-1200 r / min for 10-20 min, and then grind to a fineness ≤5μm to obtain color paste; Secondary dispersion: While stirring the above color paste, add 5-9 parts of organic matting powder and 1-3 parts of polyurethane elastic powder, and grind and disperse again for 5-10 minutes to obtain a uniform mixture; Conditioning and Discharging: Add 0.2-3 parts of compound drier, 0.1-0.5 parts of organophosphate ester delay agent, 0.3-0.7 parts of organosilicon leveling agent, and 0.4-0.8 parts of polyether defoamer to the above homogeneous mixture. Stir at 500-800 r / min for 10-20 min, and grind again until the fineness is ≤5μm to obtain the finished product. This method for preparing a scratch-resistant printing composition adopts a staged grinding-mixing process. The core is to first disperse the resin and color powder, then mix the functional fillers, and finally adjust the application performance to avoid the functional additives from failing under high shear.

[0012] The third objective of this application is to provide a printable scratch-resistant composition that can be applied to the surface of printed materials, including substrates such as ABS, PC, and aluminum alloy.

[0013] The beneficial effects are: Firstly, this application uses caprolactone diol-modified polyester polyol resin as a base, combined with a compound drying agent composed of modified polyurethane polymer and organic bismuth, to replace the traditional harmful organic tin drying agent. This not only eliminates the harm of tin to human health and the environment, but also effectively balances coating drying efficiency and application life, extending the application life to more than 4 hours, which is 2-3 times that of traditional products. This significantly improves the spraying process window, solves the pain point of short application life under traditional high viscosity systems, is suitable for mass screen printing production, and has an ink shelf life of ≥6 months with sealed storage, exhibiting excellent stability. Secondly, by abandoning the single isoflurone solvent system and adopting a compound solvent that has good compatibility with components such as caprolactone diol-modified polyester polyol resin and compound drying agent, VOC emissions can be significantly reduced, meeting the environmental protection requirements of GB 38507-2020. Thirdly, the organic matte powder made by coating fumed silica with polyamide wax, combined with the addition of polyurethane elastic powder and silicone feel additives, and with strict control of grinding fineness ≤5μm, not only gives the coating an elegant matte appearance and comfortable touch, but also significantly enhances its scratch resistance, abrasion resistance and alcohol resistance. The scratch resistance can reach 2H pencil without scratching, the abrasion resistance can be ≥5000 times, and the alcohol resistance can be ≥300 times, meeting the surface treatment requirements of high-end electronic products. Fourth, by adding organophosphate ester delay agents, the initial reaction rate is further slowed down and the construction window is optimized. Organosilicon leveling agents and polyether defoamers effectively avoid paint film sticking, poor leveling and bubble problems. At the same time, the thin coating can achieve good drying effect without excessive reliance on high temperature and long baking time, which can improve production efficiency and coating quality stability. Fifth, the introduced polycaprolactone diol modified polyester polyol resin gives the coating excellent flexibility and weather resistance. Combined with organically treated matte powder to form a micro-wrinkled structure, it achieves a stable and uniform full matte effect (60° gloss ≤ 5GU) under 4-5μm thin coating conditions while maintaining a silky feel. Furthermore, it works synergistically with polyurethane elastic powder to achieve self-healing of minor scratches within 30 seconds. In summary, this application, through synergistic innovation in formulation and process, solves the technical bottlenecks of existing coatings, such as high dosage, thick coating, significant pollution, and the presence of harmful tin elements. While ensuring high performance, it achieves synergistic optimization of environmental friendliness, workability, and coating quality, meeting the precision coating needs of high-end electronic products and demonstrating significant environmental, economic, and application benefits. Detailed Implementation

[0014] In this application, the grafting rate of caprolactone diol modified polyester polyol resin refers to the ratio of the number of molar terminal hydroxyl groups of polycaprolactone diol that have participated in the grafting reaction to the total number of molar terminal hydroxyl groups of the initially added polycaprolactone diol, expressed as a percentage, and calculated based on the molar conversion rate of polycaprolactone diol by ¹H-NMR determination.

[0015] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention.

[0016] The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the specific embodiments of the invention without inventive effort are within the protection scope of the invention.

[0017] In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the embodiments of the present invention, unless specifically specified, the technical means used are conventional means well known to those skilled in the art.

[0018] Raw material source: Divalent ester (DBE), purchased from Jinan Zhengkang Chemical Co., Ltd.; Isoflurone, also known as 3,5,5-trimethyl-2-cyclohexene-1-one, was purchased from Shandong Jinyueyuan New Materials Co., Ltd. Bismuth isooctanoate, also known as bismuth 2-ethylhexanoate, was purchased from Shandong Huian Chemical Co., Ltd. Cross-linked polyurethane color beads, brand: Dairi Seika, model: 5070D, purchased from Dongguan Hewanxing Plastics Technology Co., Ltd. Polyether-modified polydimethylsiloxane, brand Darli, model Darl-1, purchased from Hubei Darli Chemical Co., Ltd. Triphenyl phosphate, purchased from Dongguan Xingyuan Chemical Co., Ltd. Triphenyl phosphite, purchased from Shandong Xuchen Chemical Technology Co., Ltd.; The high molecular weight polyacrylate dispersants, made in the USA, brand Lubrizol, models Solsperse 32000 and Solsperse 35000, were purchased from Shenzhen Longdi Chemical Co., Ltd. Hydroxyl-terminated polydimethylsiloxane, CAS No. 15707-23-0, brand name Lanabai, purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. Polyoxyethylene polyoxypropylene glycol ether, CAS No. 9003-11-6, purchased from Jiangsu Haolong Chemical Co., Ltd. Polyester polyol resin, model HDPOL-3320P, was purchased from Shanghai Huide Technology Co., Ltd. Polycaprolactone diol (PCL, molecular weight 1000) was purchased from Jiangsu Haolong Chemical Co., Ltd. Isophorone diisocyanate (IPDI), CAS No. 4098-71-9, purchased from Shandong Xuchen Chemical Technology Co., Ltd. 1,4-Butanediol (BDO) was purchased from Shandong Xinjieao Chemical Co., Ltd. n-Butanol, purchased from Jinan Qichen Chemical Co., Ltd.; Hydroxyethyl acrylate (HEA) was purchased from Xinghengtai (Wuhan) Chemical Technology Co., Ltd. All other reagents were commercially available.

[0019] Example 1 This embodiment provides a printable scratch-resistant composition, which is prepared according to the following method: Preparation of caprolactone diol modified polyester polyol resin: Under nitrogen protection, 80 parts of polyester polyol resin with a number average molecular weight of 1500~2000 g / mol were heated to 120℃, 20 parts of polycaprolactone diol with a number average molecular weight of 1000~2000 g / mol and 0.01 parts of organic bismuth catalyst were added, the temperature was slowly raised to 140℃, and the reaction was maintained for 2 hours. When the hydroxyl value was 50~80 mgKOH / g, the acid value was ≤2 mgKOH / g, and the grafting rate was 15~25%, the reaction was stopped, and the material was cooled and discharged. Preparation of compound drying agent: 45 parts by mass of polycaprolactone diol and 28 parts by mass of isophorone diisocyanate were added to a reaction vessel under nitrogen protection, heated to 80°C, and stirred at 300 rpm for 2 hours to obtain a terminal isocyanate prepolymer; then 5 parts by mass of 1,4-butanediol were added and the reaction was continued at 85°C for 1 hour; after the reaction was completed, the temperature was lowered to 55°C, and 3 parts by mass of n-butanol were added for end-capping reaction for 0.5 hours; then 11 parts by mass of hydroxyethyl acrylate were added for end-capping modification, and the reaction was carried out at 70°C for 1 hour to obtain a modified polyurethane polymer with a number average molecular weight of approximately 8000~12000 and a viscosity of 8000~12000 mPa·s at 25°C. The above modified polyurethane polymer and organic bismuth were stirred evenly at 20°C under light-protected conditions at a mass ratio of 1:1 to obtain the compound drying agent. Preparation of organic matting powder: Heat 40 parts by mass of polyamide wax to 110°C until it is completely melted, then add 40 parts of fumed silica under high-speed stirring at 1000 rpm to fully wet and uniformly coat the surface of the fumed silica with the liquid polyamide wax. Stop heating, cool and solidify, then crush and sieve the material to obtain the organic matting powder. Premixing and grinding: Add 1 part of polymeric dispersant and 18 parts of color powder to the container, pre-disperse at 2000 r / min for 5 min, then add 58 parts of polycaprolactone diol modified polyester polyol resin, 15 parts of compound solvent and 1 part of organosilicon hand feel additive, stir at 800 r / min for 10 min, and then grind to a fineness ≤5μm to obtain color paste; Secondary dispersion: While stirring the above color paste, add 5 parts of organic matting powder and 1 part of polyurethane elastic powder, and grind and disperse again for 5 minutes to obtain a uniform mixture; Conditioning and Discharge: Add 0.2 parts of compound drying agent, 0.1 parts of organophosphate ester delay agent, 0.3 parts of organosilicon leveling agent, and 0.4 parts of polyether defoamer to the above homogeneous mixture. Stir at 500 r / min for 10 min, and grind again until the fineness is ≤5μm to obtain the finished product. The compound solvent is a mixture of divalent ester and isoflurane in a mass ratio of 2:1. The organobismuth is bismuth isooctanoate. The polyurethane elastic powder is cross-linked polyurethane color beads with a particle size of 5~8μm, selected from Daihatsu Seika 5070D. The organosilicon feel additive is polyether modified polydimethylsiloxane. The polymer dispersant is Lubrizol Solsperse 32000. The organosilicon leveling agent is hydroxyl-terminated polydimethylsiloxane, and the polyether defoamer is polyoxyethylene polyoxypropylene propylene glycol ether. When using, screen print it onto the substrate, bake at 80℃ for 2 min, and then heat to 100℃ and bake for 4 min.

[0020] Example 2 This embodiment provides a printable scratch-resistant composition, which is prepared according to the following method: Preparation of caprolactone diol modified polyester polyol resin: Under nitrogen protection, 85 parts of polyester polyol resin with a number average molecular weight of 1500~2000 g / mol were heated to 125℃, 15 parts of polycaprolactone diol with a number average molecular weight of 1000~2000 g / mol and 0.03 parts of organic bismuth catalyst were added, the temperature was slowly raised to 150℃, and the reaction was maintained for 3 hours. When the hydroxyl value was 50~80 mgKOH / g, the acid value was ≤2 mgKOH / g, and the grafting rate was 15~25%, the reaction was stopped, and the material was cooled and discharged. Preparation of compound drying agent: 50 parts by mass of polycaprolactone diol and 26 parts by mass of isophorone diisocyanate were added to a reaction vessel under nitrogen protection, heated to 85℃, and stirred at 400 rpm for 2.5 h to obtain a terminal isocyanate prepolymer; then 7 parts by mass of 1,4-butanediol were added and the reaction was continued at 90℃ for 1.5 h; after the reaction was completed, the temperature was lowered to 60℃, and 3.5 parts by mass of n-butanol were added for end-capping reaction for 1 h; then 13 parts by mass of hydroxyethyl acrylate were added for end-capping modification, and the reaction was carried out at 75℃ for 1.5 h to obtain a modified polyurethane polymer with a number average molecular weight of approximately 8000~12000 and a viscosity of 8000~12000 mPa·s at 25℃. The modified polyurethane polymer and organic bismuth were stirred evenly at 25℃ under light-protected conditions at a mass ratio of 1:1 to obtain the compound drying agent. Preparation of organic matting powder: Heat 50 parts of polyamide wax to 120°C to melt it completely, then add 35 parts of fumed silica under high-speed stirring at 1500 rpm to fully wet and evenly coat the surface of the fumed silica with the liquid polyamide wax. Stop heating, cool and solidify, then crush and sieve the material to obtain organic matting powder. Premixing and grinding: Add 2 parts of polymeric dispersant and 20 parts of color powder to a container, pre-disperse at 2500 r / min for 10 min, then add 44 parts of polycaprolactone diol modified polyester polyol resin, 20 parts of compound solvent, and 2 parts of organosilicon hand feel additive, stir at 1000 r / min for 15 min, and then grind to a fineness ≤5μm to obtain color paste; Secondary dispersion: While stirring the above color paste, add 7 parts of organic matting powder and 2 parts of polyurethane elastic powder, and grind and disperse again for 7 minutes to obtain a uniform mixture; Conditioning and Discharging: Add 1.6 parts of compound drying agent, 0.3 parts of organophosphate ester delay agent, 0.5 parts of organosilicon leveling agent, and 0.6 parts of polyether defoamer to the above homogeneous mixture. Stir at 700 r / min for 15 min, and grind again until the fineness is ≤5μm to obtain the finished product. The compound solvent is a mixture of divalent ester and isoflurane in a mass ratio of 3:1. The organobismuth is bismuth isooctanoate. The polyurethane elastic powder is cross-linked polyurethane color beads with a particle size of 5~8μm, selected from Daihatsu Seika 5070D. The organosilicon feel additive is polyether modified polydimethylsiloxane. The polymer dispersant is Lubrizol Solsperse 35000. The organosilicon leveling agent is hydroxyl-terminated polydimethylsiloxane, and the polyether defoamer is polyoxyethylene polyoxypropylene propylene glycol ether. When using, screen print it onto the substrate, bake at 80℃ for 3 min, and then heat to 100℃ and bake for 5 min.

[0021] Example 3 This embodiment provides a printable scratch-resistant composition, which is prepared according to the following method: Preparation of caprolactone diol modified polyester polyol resin: Under nitrogen protection, 90 parts of polyester polyol resin with a number average molecular weight of 1500~2000 g / mol were heated to 130℃, 10 parts of polycaprolactone diol with a number average molecular weight of 1000~2000 g / mol and 0.05 parts of organic bismuth catalyst were added, the temperature was slowly raised to 160℃, and the reaction was maintained at this temperature for 4 hours. When the hydroxyl value was 50~80 mgKOH / g, the acid value was ≤2 mgKOH / g, and the grafting rate was 15~25%, the reaction was stopped, and the material was cooled and discharged. Preparation of compound drying agent: 55 parts by mass of polycaprolactone diol and 24 parts by mass of isophorone diisocyanate were added to a reaction vessel under nitrogen protection, heated to 90℃, and stirred at 500 rpm for 3 hours to obtain a terminal isocyanate prepolymer; then 9 parts by mass of 1,4-butanediol were added and the reaction was continued at 95℃ for 2 hours; after the reaction was completed, the temperature was lowered to 65℃, and 4 parts by mass of n-butanol were added for end-capping reaction for 1.5 hours; then 15 parts by mass of hydroxyethyl acrylate were added for end-capping modification, and the reaction was carried out at 80℃ for 2 hours to obtain a modified polyurethane polymer with a number average molecular weight of approximately 8000~12000 and a viscosity of 8000~12000 mPa·s at 25℃. The modified polyurethane polymer and organic bismuth were stirred evenly at 30℃ under light-protected conditions at a mass ratio of 2:1 to obtain the compound drying agent. Preparation of organic matting powder: Heat 60 parts by weight of polyamide wax to 130°C until it is completely melted, then add 30 parts of fumed silica under high-speed stirring at 2000 rpm to fully wet and evenly coat the surface of the fumed silica with the liquid polyamide wax. Stop heating, cool and solidify, then crush and sieve the material to obtain organic matting powder. Premixing and grinding: Add 3 parts of polymeric dispersant and 22 parts of color powder to the container, pre-disperse at 3000 r / min for 15 min, then add 30 parts of polycaprolactone diol modified polyester polyol resin, 25 parts of compound solvent and 3 parts of organosilicon hand feel additive, stir at 1200 r / min for 20 min, and then grind to a fineness ≤5μm to obtain color paste; Secondary dispersion: While stirring the above color paste, add 9 parts of organic matting powder and 3 parts of polyurethane elastic powder, and grind and disperse again for 10 minutes to obtain a uniform mixture; Conditioning and Discharging: Add 3 parts of compound drying agent, 0.5 parts of organophosphate ester delay agent, 0.7 parts of organosilicon leveling agent and 0.8 parts of polyether defoamer to the above homogeneous mixture, stir at 800 r / min for 20 min, and grind again until the fineness is ≤5μm to obtain the finished product; wherein the compound solvent is a mixture of divalent acid ester and isoflurane in a mass ratio of 4:1; wherein the organobismuth is bismuth isooctanoate; the polyurethane elastic powder is cross-linked polyurethane color beads with a particle size of 5~8μm, selected from Daihatsu Seika 5070D; the organosilicon feel additive is polyether modified polydimethylsiloxane; the polymeric dispersant is composed of Lubrizol Solsperse 32000 and Solsperse 35000 in a mass ratio of 1:1; the organosilicon leveling agent is hydroxyl-terminated polydimethylsiloxane, and the polyether defoamer is polyoxyethylene polyoxypropylene propylene glycol ether. When using, the material is screen-printed onto the substrate, baked at 80℃ for 5 minutes, and then heated to 100℃ for 6 minutes.

[0022] Comparative Example 1 The difference between this application and Example 2 is that 44 parts of polyester polyol resin are replaced with 44 parts of caprolactone diol modified polyester polyol resin in Example 2, while the other components and experimental steps are the same as in Example 2.

[0023] Comparative Example 2 The difference between this application and Example 2 is that 1.6 parts of dibutyltin dilaurate (organotin) are used to replace 1.6 parts of the compound drying agent in Example 2, while the other components and experimental steps are the same as in Example 2.

[0024] Comparative Example 3 The difference between this application and Example 2 is that 44 parts of polyester polyol resin are used instead of 44 parts of caprolactone diol modified polyester polyol resin in Example 2, and 1.6 parts of dibutyltin dilaurate (organotin) are used instead of 1.6 parts of the compounded drying agent in Example 2. In use, a spray coating process is employed to form a film.

[0025] Comparative Example 4 The difference between this application and Example 2 is that 7 parts of fumed silica are used to replace 7 parts of organic matting powder in Example 2, while the other components and experimental steps are the same as in Example 2.

[0026] The printing compositions prepared in Examples 1-3 and Comparative Examples 1-3 were tested.

[0027] Test method: Gloss was tested according to GB / T 9754-2007 (60° incident angle) standard; Scratch resistance is in accordance with GB / T 6739-2021 (2H pencil, 500g force, cross-cut test). Self-healing time: After slight scratching by a hard object, observe the time it takes for the scratch to disappear at 25℃; Abrasion resistance is measured according to GB / T1768-2021 (500g force, suede cloth, number of reciprocating rubs until the base material is exposed). Alcohol resistance is tested by soaking cotton cloth in 95% ethanol and wiping with 500g force until the substrate is exposed. Application life: The time it takes for the ink viscosity to rise to 150% of its initial value at 25°C; VOCs content was tested according to GB / T 38608-2020 standard; Storage shelf life: Record the time when stratification or sedimentation first occurs.

[0028] The test results are shown in Table 1.

[0029] Table 1. Results of Performance Tests on Printing Compositions

[0030] (Note: The feel rating was determined by a blind test conducted by 10 people, with 5 points being the best skin feel and 1 point being rough.) Based on the experimental data above, the 4-5μm coatings obtained by screen printing in Examples 1-3 can maintain a stable and uniform matte finish, extend the application life to more than 4 hours, achieve a scratch resistance of 2H pencil without scratches, withstand ≥5000 abrasion cycles, withstand ≥300 alcohol cycles, can complete self-repair within 30 seconds, and have a shelf life of up to 12 months.

[0031] Compared to Example 2, in Comparative Example 1, replacing the caprolactone diol-modified polyester polyol resin with polyester polyol resin resulted in increased coating gloss, decreased scratch resistance, prolonged self-healing time, reduced abrasion and alcohol resistance, and a rougher feel. This may be because the unmodified polyester polyol resin lacks the flexible segments and grafted structure of polycaprolactone diol, leading to poor compatibility with components such as matte powder and elastic powder. This results in an uneven microstructure and insufficient flexibility in the coating, thus affecting the matte finish, scratch resistance, and self-healing properties. Furthermore, the hydroxyl value and acid value of the unmodified resin may not have been optimized, resulting in insufficient crosslinking density and reduced mechanical strength and chemical resistance of the coating.

[0032] Compared to Example 2, Comparative Example 2, replacing the compound drier with dibutyltin dilaurate (organotin), resulted in a significantly shortened application life, decreased scratch resistance, and reduced abrasion and alcohol resistance. This may be because while the organotin drier has high catalytic efficiency, its reaction rate is too fast, leading to a rapid increase in system viscosity, a short application window, and potentially uneven curing of the coating, affecting film density and mechanical properties. Furthermore, the poor compatibility of organotin with the resin system may result in uneven drier distribution, further reducing coating uniformity and durability.

[0033] Compared to Example 2, Comparative Example 3 replaced the caprolactone diol-modified polyester polyol resin with the polyester polyol resin, and replaced the compound drier with dibutyltin dilaurate. This resulted in an increased coating thickness, but the expected performance was still not achieved. The coating exhibited increased gloss, poor scratch resistance, slow self-healing, and poor abrasion and alcohol resistance. This may be because the combination of the unmodified resin and the organotin drier lacks a synergistic effect. Both the resin's flexibility and the drier's application adaptability are insufficient, requiring a thicker coating to partially cover the substrate in spraying processes. However, the loose internal structure and low crosslinking density of the coating lead to a decline in overall performance. Furthermore, the toxicity of organotin may affect system stability and accelerate component degradation.

[0034] Compared to Example 2, Comparative Example 4, replacing the organic-treated matting powder with fumed silica resulted in increased coating gloss, decreased scratch resistance, prolonged self-healing time, reduced abrasion and alcohol resistance, and a worse feel. This is likely because the untreated matting powder has a high surface energy, making it prone to agglomeration and uneven dispersion in the coating, forming localized aggregation points that disrupt the surface smoothness. Furthermore, its weak adhesion to the resin matrix makes it easily scratched off, and it cannot effectively synergize with the polyurethane elastic powder to achieve microscopic self-healing. The lack of polyamide wax coating also reduces the compatibility between the matting powder and the resin, affecting the uniformity of matte finish and the smoothness of the feel.

[0035] In summary, this application, through synergistic innovation in formulation and process, solves the technical bottlenecks of existing coatings, such as high dosage, thick coating, significant pollution, and the presence of harmful tin elements. While ensuring high performance, it achieves synergistic optimization of environmental friendliness, workability, and coating quality, meeting the precision coating needs of high-end electronic products and demonstrating significant environmental, economic, and application benefits.

[0036] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A printable scratch-resistant composition, characterized in that, By weight, it consists of 30-58 parts polycaprolactone diol-modified polyester polyol resin, 15-25 parts compound solvent, 5-9 parts organic matting agent, 1-3 parts silicone hand feel additive, 1-3 parts polyurethane elastic powder, 0.2-3 parts compound drying agent, 0.1-0.5 parts organophosphate ester delay agent, 1-3 parts polymeric dispersant, 0.3-0.7 parts silicone leveling agent, 0.4-0.8 parts polyether defoamer, and 18-22 parts colorant; wherein, The polycaprolactone diol-modified polyester polyol resin has a hydroxyl value of 50-80 mgKOH / g, an acid value ≤2 mgKOH / g, and a grafting rate of 15-25%. The compound solvent is a mixture of divalent ester and isoflurone in a mass ratio of 2-4:

1. The compound drying agent is composed of modified polyurethane polymer and organic bismuth in a mass ratio of 1~2:

1.

2. The printable scratch-resistant composition according to claim 1, characterized in that, The organic matting powder is polyamide wax-coated fumed silica with a particle size of 2~3μm.

3. The printable scratch-resistant composition according to claim 1, characterized in that, The organic bismuth is bismuth isooctanoate.

4. The printable scratch-resistant composition according to claim 1, characterized in that, The polyurethane elastic powder is a cross-linked polyurethane color bead with a particle size of 5~8μm, selected from Daihatsu Seika 5070D.

5. The printable scratch-resistant composition according to claim 1, characterized in that, The organosilicon feel-enhancing agent is polyether-modified polydimethylsiloxane.

6. The printable scratch-resistant composition according to claim 1, characterized in that, The organophosphate delay agent is triphenyl phosphate or triphenyl phosphite.

7. The printable scratch-resistant composition according to claim 1, characterized in that, The polymeric dispersant is selected from at least one of Lubrizol Solsperse 32000 and Solsperse 35000.

8. The printable scratch-resistant composition according to claim 1, characterized in that, The organosilicon leveling agent is hydroxyl-terminated polydimethylsiloxane, and the polyether defoamer is polyoxyethylene polyoxypropylene propylene glycol ether.

9. The printable scratch-resistant composition according to claim 1, characterized in that, Its preparation method is as follows: Preparation of caprolactone diol modified polyester polyol resin: Under nitrogen protection, 80-90 parts of polyester polyol resin with a number average molecular weight of 1500-2000 g / mol were heated to 120-130℃, 10-20 parts of polycaprolactone diol with a number average molecular weight of 1000-2000 g / mol and 0.01-0.05 parts of organic bismuth catalyst were added, the temperature was slowly raised to 140-160℃, and the reaction was maintained for 2-4 hours. When the hydroxyl value was 50-80 mgKOH / g, the acid value was ≤2 mgKOH / g, and the grafting rate was 15-25%, the reaction was stopped, and the material was cooled and discharged. Preparation of compound drying agent: 45-55 parts by weight of polycaprolactone diol and 24-28 parts by weight of isophorone diisocyanate were added to a reaction vessel under nitrogen protection. The mixture was heated to 80-90℃ and stirred at 300-500 rpm for 2-3 hours to obtain an isocyanate-terminated prepolymer. Then, 5-9 parts by weight of 1,4-butanediol were added, and the reaction was continued at 85-95℃ for 1-2 hours. After the reaction was completed, the temperature was lowered to 55-65℃, and 3-4 parts by weight of the positively charged isocyanate prepolymer were added. Butanol end-capping reaction for 0.5-1.5 h; then 11-15 parts of hydroxyethyl acrylate are added for end-capping modification, and the reaction is carried out at 70-80℃ for 1-2 h to obtain a modified polyurethane polymer with a number average molecular weight of about 8000-12000 and a viscosity of 8000-12000 mPa·s at 25℃. The modified polyurethane polymer and organic bismuth are stirred evenly at 20-30℃ under light-protected conditions at a mass ratio of 1-2:1 to obtain the compound drying agent. Preparation of organic matting powder: Heat 40-60 parts by weight of polyamide wax to 110-130℃ until it is completely melted, and then add 30-40 parts of fumed silica under high-speed stirring at a stirring speed of 1000-2000 rpm to fully wet and uniformly coat the surface of the fumed silica with the liquid polyamide wax. Stop heating, cool and solidify, and then crush and sieve the material to obtain the organic matting powder with a particle size of 2-3 μm. Premixing and grinding: Add 1-3 parts of polymeric dispersant and 18-22 parts of color powder to a container, pre-disperse at 2000-3000 r / min for 5-15 min, then add 30-58 parts of polycaprolactone diol modified polyester polyol resin, 15-25 parts of compound solvent, and 1-3 parts of organosilicon hand feel additive, stir at 800-1200 r / min for 10-20 min, and then grind to a fineness ≤5μm to obtain color paste; Secondary dispersion: While stirring, add 5-9 parts of organic matting powder and 1-3 parts of polyurethane elastic powder to the color paste, and grind and disperse again for 5-10 minutes to obtain a uniform mixture; Conditioning and discharging: Add 0.2-3 parts of compound drying agent, 0.1-0.5 parts of organophosphate ester delay agent, 0.3-0.7 parts of organosilicon leveling agent and 0.4-0.8 parts of polyether defoamer to the homogeneous mixture, stir at 500-800 r / min for 10-20 min, and grind again until the fineness is ≤5μm to obtain the finished product.

10. The printable scratch-resistant composition according to claim 1, characterized in that, It is applied to the surface of printed materials.

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