A solvent-based matte transparent coating with high resistance to nail scratches, its preparation method and application

Abstract

This invention relates to the field of chemical coatings technology, specifically to a solvent-based, highly scratch-resistant, matte transparent coating, its preparation method, and its application. The invention provides a coating comprising the following components by weight: Component A includes 32-42 parts of a specific adipic acid-type polyester diol resin; 32-42 parts of a specific hydroxyl acrylic resin; 10-15 parts of matting agent; and 8-12 parts of diisobutyl ketone; Component B includes a curing agent; and Component C includes a diluent. The mass ratio of components A, B, and C is 1:(0.2-0.4):(0.6-1.8). This coating exhibits excellent self-healing properties and a certain degree of fingerprint resistance after nail scratches, significantly overcoming the shortcomings of existing coatings.

Description

Technical Field

[0001] This application relates to the field of chemical coatings technology, and in particular to a solvent-based matte transparent coating with high resistance to nail scratches, its preparation method, and its application. Background Technology

[0002] In daily life, the surfaces of electronic product casings, automotive interior and exterior parts, household appliances, and furniture are often scratched by sharp objects such as fingernails or have fingerprints adhering to them, affecting their appearance and lifespan. Currently available paint products often struggle to balance self-healing properties after scratches with fingerprint resistance. While traditional matte paints offer some self-healing capabilities, they generally neglect fingerprint resistance, making it difficult to meet consumers' comprehensive requirements for lasting aesthetics and durability in actual use.

[0003] To address the aforementioned issues, existing technology CN116622279A discloses a scratch-self-healing polyurethane matte clear topcoat. This coating utilizes elastic resin for rapid self-drying and automatically repairs scratches after the stress is relieved through coating rebound, representing some progress in self-healing functionality. However, this solution requires 7 days to restore 90% of the repair effect, which is insufficient for rapid repair in practical applications, and the self-healing speed still needs improvement. Furthermore, this technology does not address the surface's anti-fingerprint properties; fingerprint residue remains easily left when exposed to everyday fingerprints, limiting its application in high-end consumer products, automotive interiors, and other fields with high fingerprint resistance requirements.

[0004] Therefore, there is an urgent need to develop a coating that has a rapid self-healing function for nail scratches and anti-fingerprint properties, so as to fully meet users' actual needs for surface durability and ease of cleaning. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects and deficiencies of existing coatings that cannot simultaneously achieve rapid self-healing against scratches and fingerprint resistance, and to provide a coating.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned coating.

[0007] Another object of the present invention is to provide the application of the above-mentioned coatings in the manufacture of electronic products, household appliances or automotive parts.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution: This invention protects a coating, which, by weight, comprises the following components: Component A: 32-42 parts of adipic acid type polyester diol resin; 32-42 parts of hydroxyl acrylic resin; 10-15 parts of matte powder; 8-12 parts of diisobutyl ketone; Component B: Curing agent; Component C: Diluent; The mass ratio of component A, component B, and component C is 1:(0.2~0.4):(0.6~1.8). The adipic acid-type polyester diol resin has a number average molecular weight of 900-1100 and a viscosity of 2800-3600 cps. The hydroxyl value of the hydroxyl acrylic resin is 75~100 mgKOH / g.

[0009] To address the technical challenge of existing coatings failing to simultaneously achieve rapid self-healing of scratches and fingerprint resistance, this invention employs a composite formulation system for synergistic optimization design. This invention selects a specific adipic acid-type polyester diol resin and a specific hydroxyl acrylic resin as the film-forming matrix. These two resins exhibit excellent compatibility, and when combined with a curing agent, they form a homogeneous and stable cross-linked film network. The synergistic effect on self-healing performance is as follows: the adipic acid-type polyester diol, with its specific number-average molecular weight and viscosity, contains a certain degree of flexible aliphatic long chains in its main chain, while exhibiting high entanglement between molecular chains, forming the structural basis for the coating's self-healing and providing excellent deformation recovery capability for the paint film. The hydroxyl acrylic resin with a specific hydroxyl value possesses high hydroxyl functionality and main chain rigidity, increasing the cross-linking density and overall hardness of the paint film, preventing permanent deformation after external force. The combination of these two resins constructs a mutually compatible network structure of "rigid framework support + flexible segment filling," ensuring both the basic mechanical strength of the paint film and endowing it with excellent scratch self-healing performance. Building upon this foundation, the introduction of diisobutyl ketone into the system can simultaneously regulate the system's viscosity and wetting / leveling properties, improve the uniformity of resin molecule arrangement during film formation, enhance the density and uniformity of the paint film surface, further ensure the freedom of flexible segments, and strengthen the scratch self-healing effect. Simultaneously, the matting powder compounded in the system can produce a synergistic effect with the film-forming resin, constructing a uniform microscopic matting structure on the paint film surface, reducing the contact area and adhesion of fingerprint grease, and endowing the paint film with a stable anti-fingerprint effect.

[0010] In this invention, the amount of adipic acid-type polyester diol resin in component A can be 32, 35, 38, 39, 40, 41, or 42 parts by weight, or any two of the above values; the amount of hydroxyl acrylic resin can be 32, 34, 35, 36, 37, 38, 40, or 42 parts by weight, or any two of the above values; the amount of matting agent can be 10, 12, 12.5, 13, or 15 parts by weight, or any two of the above values; and the amount of diisobutyl ketone can be 8, 9, 10, or 12 parts by weight, or any two of the above values.

[0011] In this invention, the content of adipic acid type polyester diol resin accounts for more than 25 wt% of component A in the coating.

[0012] Furthermore, the hydroxyl value of the adipic acid-type polyester diol resin is 90~125 mgKOH / g.

[0013] In this invention, the hydroxyl value of the adipic acid type polyester diol resin can be measured by an automatic potentiometric titrator.

[0014] Furthermore, the comonomers of the adipic acid-type polyester diol resin include adipic acid and diol.

[0015] Furthermore, the diol includes one or more of methylpropanediol, 1,6-hexanediol, 1,4-butanediol, and neopentyl glycol.

[0016] Preferably, the diol includes one or more of methylpropanediol, 1,6-hexanediol, and 1,4-butanediol.

[0017] In this invention, the viscosity of the resin can be measured using a digital rotational viscometer.

[0018] In this invention, the number-average molecular weight of the adipic acid-type polyester diol resin can be determined by gel permeation chromatography.

[0019] Furthermore, the viscosity of the hydroxyl acrylic resin is 2300~2500 cps.

[0020] Furthermore, the mass ratio of the adipic acid-type polyester diol resin to the hydroxyl acrylic resin is 1:(0.7~1.4).

[0021] Furthermore, the matting agent is a hydrophobic silica-based matting agent.

[0022] Furthermore, the specific surface area of ​​the matting agent is 180~250 m². 2 / g.

[0023] Furthermore, component A also includes the following components in parts by weight: 5.6 to 15 parts of other additives.

[0024] Furthermore, the other additives include one or more of solvents, fillers, dispersants, leveling agents, light stabilizers, and antisettling agents.

[0025] Typically, in coatings, the amount of solvent is 2 to 8 parts, the amount of filler is 0.2 to 0.4 parts, the amount of dispersant is 0.8 to 1.2 parts, the amount of leveling agent is 0.8 to 1.2 parts, the amount of light stabilizer is 0.8 to 1.2 parts, and the amount of anti-settling agent is 1 to 3 parts.

[0026] Furthermore, the solvent includes one or both of ethyl acetate and butyl acetate.

[0027] Furthermore, the average particle size of the filler is ≤25 nm.

[0028] Preferably, the filler comprises one or more of nano-alumina, nano-zirconia, and nano-zinc oxide.

[0029] Furthermore, the dispersant includes one or more of anionic dispersants, cationic dispersants, and nonionic dispersants.

[0030] Furthermore, the leveling agent includes one or more of acrylic leveling agents, silicone leveling agents, and polyurethane leveling agents.

[0031] Furthermore, the light stabilizer includes one or both of hindered amine light stabilizers and ultraviolet absorbers.

[0032] Furthermore, the anti-settling agent includes one or more of polyamide wax-based anti-settling agents and polyurea-based anti-settling agents.

[0033] Furthermore, the curing agent is an HDI-based curing agent.

[0034] Furthermore, the diluent includes one or more of ethyl acetate, butyl acetate, diisobutyl ketone, diacetone alcohol, and propylene glycol methyl ether acetate.

[0035] Furthermore, the diluent has the following mass ratio: ethyl acetate: propylene glycol methyl ether acetate: butyl acetate: diisobutyl ketone: diacetone alcohol = (40~60): (10~30): (5~15): (5~15): (5~15). This composite diluent can more effectively adjust the viscosity of the coating, improve the leveling properties during application, and reduce the amount of coating used, thus helping to reduce costs and improve application efficiency.

[0036] This invention protects the method for preparing the aforementioned coating, comprising the following steps: Mix components A through C thoroughly according to the formula to obtain the coating.

[0037] Furthermore, as a preferred method, component A is mixed by the following steps: According to the formula, mix adipic acid type polyester diol resin, hydroxy acrylic resin and diisobutyl ketone evenly, then add matting powder and mix thoroughly to obtain the mixed component A.

[0038] Furthermore, the mixing speed is 500~1000 r / min.

[0039] Furthermore, the mixing time is 10-50 min.

[0040] Furthermore, the rotational speed for thorough mixing is 100~400 r / min.

[0041] Furthermore, the time for thorough mixing is 1 to 10 minutes.

[0042] This invention protects the use of the aforementioned coatings in the manufacture of electronic products, household appliances, or automotive parts.

[0043] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a coating that exhibits excellent self-healing properties and a certain degree of anti-fingerprint properties after being scratched by a fingernail, greatly solving the performance defects and shortcomings of existing coatings in the manufacture of electronic products, household appliances, or automotive parts. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0045] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0046] Diol Resin 1#: Tetrameric adipic acid type polyester diol (comonomers are adipic acid, methyl propylene glycol, 1,6-hexanediol and 1,4-butanediol), M102, number average molecular weight 1000, hydroxyl value 112 mgKOH / g, viscosity 3340 cps, produced by Dongguan Zuorong Industrial Co., Ltd. Diol Resin 2#: Tetrameric adipic acid type polyester diol (comonomers are adipic acid, methyl propylene glycol, 1,6-hexanediol and 1,4-butanediol), M103, number average molecular weight 1000, hydroxyl value 105 mgKOH / g, viscosity 2980 cps, produced by Dongguan Zuorong Industrial Co., Ltd. Diol Resin 3#: A five-component copolymer of adipic acid-type polyester diol (comonomers are adipic acid, methyl propylene glycol, 1,6-hexanediol, 1,4-butanediol and neopentyl glycol), M101, number average molecular weight 1000, hydroxyl value 105 mgKOH / g, viscosity 3500cps, produced by Dongguan Zuorong Industrial Co., Ltd. Diol Resin 4#: Di-copolymer adipate-type polyester diol (comonomers are adipate and diethylene glycol), WHP-108, number average molecular weight 1000, hydroxyl value 112 mgKOH / g, viscosity 225 cps, produced by Shandong Wanhua Chemical Group Co., Ltd. Diol Resin 5#: Di-copolymer adipate-type polyester diol (comonomers are adipate and propylene glycol), WHP-308, number average molecular weight 3000, hydroxyl value 37 mgKOH / g, viscosity 3585 cps, produced by Shandong Wanhua Chemical Group Co., Ltd. Diol resin 6#: Polycaprolactone diol, 2102, number average molecular weight 1000, hydroxyl value 113 mgKOH / g, viscosity 3118 cps, produced by Hunan Juren New Material Co., Ltd. Hydroxy acrylic resin 1#: ADH905B, viscosity 2420 cps, hydroxyl value: 95 mgKOH / g, produced by Nanxiong Sanben Chemical Technology Co., Ltd.; Hydroxy acrylic resin 2#: KN5452P, viscosity 2450 cps, hydroxyl value: 80 mgKOH / g, produced by Guangdong Kelisen Resin Co., Ltd. Hydroxy acrylic resin 3#: KN1051F, viscosity 2415 cps, hydroxyl value: 40 mgKOH / g, produced by Guangdong Kelisen Resin Co., Ltd. Diisobutyl ketone: Commercially available; Wetting agent: Organosilicon wetting agent, Efka SL 3030, manufactured by BASF, Germany; Viscosity modifier: Butyl acetate, commercially available; Matting agent: Hydrophobic silica-based matting agent, SYLOPHOBIC-100, 220 μm 2 / g, produced in Fuji, Japan; Filler: Nano alumina, DK410-2, 20 nm, produced by Beijing Deco Island Gold Co., Ltd. Dispersant: Nonionic dispersant, BYK2009, manufactured by BYK in Germany; Leveling agent: Organosilicon leveling agent, BYK333, manufactured by BYK in Germany; Light stabilizer: Hindered amine light stabilizer, Tinuvin 292, manufactured by BASF, Germany; Anti-settling agent: Amide wax anti-settling agent, DISPARON NS-5503, produced by Kusumoto Chemical Co., Ltd.; Solvent: Ethyl acetate, commercially available; Curing agent: HDI type curing agent, N3390, manufactured by Bayer, Germany; Diluent: Composite diluent, mass ratio of ethyl acetate: propylene glycol methyl ether acetate: butyl acetate: diisobutyl ketone: diacetone alcohol = 50:20:10:10:10.

[0047] The coatings of the various embodiments and comparative examples of the present invention were prepared by the following process: According to the formula, the diol resin, hydroxyl acrylic resin, diisobutyl ketone, wetting agent (if any), and viscosity modifier (if any) are stirred and mixed at 600 r / min for 15 min. Then, the matting agent, nano alumina, dispersant, leveling agent, light stabilizer, ethyl acetate, and anti-settling agent are added, and the mixture is thoroughly mixed at 900 r / min for 25 min to obtain the mixed component A. Subsequently, component B (curing agent) and component C (diluent) are added to the mixed component A, and the mixture is stirred at 250 r / min for 5 minutes to obtain the coating.

[0048] Examples 1-8 Examples 1-8 provide a series of coatings, the weight parts of each component in their formulations are shown in Table 1.

[0049] Table 1 Formulations of Examples 1-8

[0050] Comparative Examples 1-7 Comparative Examples 1 to 7 provide a series of coatings, the weight parts of each component in their formulations are shown in Table 2.

[0051] Table 2 Formulations of Comparative Examples 1-7

[0052] Coating performance testing (1) Experimental methods The coatings of each embodiment and comparative example were sprayed onto PC black plastic sheets, dried at 75 ℃ for 4 h, and allowed to stand for 24 h to obtain a paint film with a thickness of 30 µm and a gloss of 1 gloss. For each embodiment and comparative example sample, three sets of parallel samples were set up for various performance tests, and the average value of the test results was taken.

[0053] Self-healing performance test: The surface of the paint film was intentionally scratched with a fingernail (without penetrating the coating). The sample was placed at room temperature and the degree of repair was visually observed. The time required for the scratch to heal to approximately 90% was recorded. Repair time was used as the evaluation index for self-healing performance—the shorter the repair time, the better the self-healing performance of the paint film.

[0054] Fingerprint resistance test: Press your finger on the paint film surface to leave a fingerprint, then wipe it with a dry, lint-free cloth and visually observe the fingerprint residue after wiping; evaluate according to the following levels: Grade 0: No visible fingerprints remain after wiping; the surface is clean and streak-free, demonstrating excellent fingerprint resistance. Level 1: After wiping, some fingerprint outline remains, the pattern is not easily distinguishable, and the fingerprint resistance is good; Level 2: The fingerprint structure remains intact after wiping, making it difficult to remove; its anti-fingerprint performance is poor.

[0055] Abrasion resistance test: The test was conducted using an RCA paper tape abrasion tester with Norman standard test paper tape from the United States under a load of 175 g. One rotation of the equipment was counted as one test. The number of tests when the paint film was worn through and the substrate was exposed was recorded. The higher the number of tests, the better the abrasion resistance.

[0056] (2) Experimental results Table 3 Performance results of each embodiment and comparative example

[0057] As shown in Table 3, the self-healing time of nail scratches of the coatings prepared in Examples 1 to 8 of the present invention is ≤24 h, the anti-fingerprint level is ≤1, and the wear resistance is >180 times. This indicates that the coatings of the present invention have excellent self-healing properties, anti-fingerprint properties and wear resistance.

[0058] In comparison, Comparative Example 1 suffered from poor scratch self-healing, fingerprint resistance, and abrasion resistance due to the low viscosity of diol resin 4#; Comparative Example 2 suffered from poor scratch self-healing, fingerprint resistance, and abrasion resistance due to the excessively high number-average molecular weight and insufficient hydroxyl value of diol resin 5#; Comparative Example 3 suffered from poor scratch self-healing, fingerprint resistance, and abrasion resistance due to the insufficient compatibility between diol resin 6# and hydroxyl acrylic resin, which failed to maintain the resin's flexibility; Comparative Example 4 suffered from poor abrasion resistance and fingerprint resistance due to insufficient hydroxyl acrylic resin, resulting in only half-gloss. Comparative Example 5 suffered from poor scratch self-healing and fingerprint resistance due to excessive hydroxyl acrylic resin; and Comparative Example 6 suffered from poor scratch self-healing, fingerprint resistance, and abrasion resistance due to insufficient film density caused by the use of hydroxyl acrylic resin 3# instead of hydroxyl acrylic resin 1#, which resulted in an insufficiently dense paint film due to the low hydroxyl value. Comparative Example 7 used wetting agents and viscosity modifiers instead of diisobutyl ketone. Due to the poor compatibility between the two, it failed to effectively improve the density and uniformity of the paint film surface in this invention, resulting in poor scratch self-healing properties.

[0059] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A coating, characterized in that, By weight, it includes the following components: Component A: 32-42 parts of adipic acid type polyester diol resin; 32-42 parts of hydroxyl acrylic resin; 10-15 parts of matte powder; 8-12 parts of diisobutyl ketone; Component B: Curing agent; Component C: Diluent; The mass ratio of component A, component B, and component C is 1:(0.2~0.4):(0.6~1.8). The adipic acid-type polyester diol resin has a number average molecular weight of 900-1100 and a viscosity of 2800-3600 cps. The hydroxyl value of the hydroxyl acrylic resin is 75~100 mgKOH / g.

2. The coating according to claim 1, characterized in that, The hydroxyl value of the adipic acid-type polyester diol resin is 90~125 mgKOH / g.

3. The coating according to claim 1, characterized in that, The viscosity of the hydroxyl acrylic resin is 2300~2500 cps.

4. The coating according to claim 1, characterized in that, The mass ratio of the adipic acid-type polyester diol resin to the hydroxyl acrylic resin is 1:(0.7~1.4).

5. The coating according to claim 1, characterized in that, The comonomers of the adipic acid-type polyester diol include adipic acid and diol. The diol includes one or more of methylpropanediol, 1,6-hexanediol, 1,4-butanediol, and neopentyl glycol.

6. The coating according to claim 1, characterized in that, Component A also includes the following components in parts by weight: 5.6 to 15 parts of other additives.

7. The coating according to claim 6, characterized in that, The other additives include one or more of the following: solvents, fillers, dispersants, leveling agents, light stabilizers, and antisettling agents.

8. The coating according to claim 7, characterized in that, The average particle size of the filler is ≤25 nm.

9. A method for preparing the coating according to any one of claims 1 to 8, characterized in that, Includes the following steps: Mix components A through C thoroughly according to the formula to obtain the coating.

10. The use of the coating according to any one of claims 1 to 8 in the manufacture of electronic products, household appliances or automotive parts.

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