Wear-resistant coating for MS resin as well as preparation method and application of wear-resistant coating

Abstract

The invention discloses a wear-resistant coating for MS resin as well as a preparation method and application of the wear-resistant coating, and belongs to the technical field of preparation of organic wear-resistant coatings. The preparation method comprises the following steps: mixing a double-bond silane compound with an epoxy silane compound, and acidifying to obtain a silicon hydroxyl mixture; mixing and condensing the silicon hydroxyl mixture and weak base to obtain polysiloxane; the preparation method comprises the following steps: mixing polysiloxane and sulfydryl carboxylic acid, and catalyzing by an initiator to obtain carboxylated polysiloxane; carboxylated polysiloxane and copper sulfate are mixed and stirred to form a coating solution; mS resin is rapidly immersed in the coating liquid after being subjected to oxygen plasma pretreatment and then is lifted and pulled, and then the wear-resistant coating for the MS resin is obtained through curing. According to the preparation method disclosed by the invention, the adhesion between the wear-resistant coating and the MS resin is increased and the wear resistance and the light transmittance of the MS resin are improved on the basis of not completely destroying the deep structure of the MS resin through the synergistic cooperation of the metal coordination, the covalent cross-linking and the hydrogen bonds formed by the plasma pretreatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic wear-resistant coating preparation, and particularly relates to a wear-resistant coating for MS resin, a preparation method thereof, and an application thereof. Background Art

[0002] The Chinese name of MS resin is styrene-methyl methacrylate copolymer resin, which is mainly a resin material prepared by the polymerization reaction of monomer methyl methacrylate (MMA) and monomer styrene (St). In addition to having the advantages of good processing fluidity and low hygroscopicity of styrene, it also has the weather resistance and excellent optical properties of methyl methacrylate. Therefore, it has important applications in fields such as building decoration materials, advertising display boards, transparent casings of electronic appliances, and transparent lamp shades in the automotive industry. However, due to the relatively low hardness of MS resin itself, it is easy to produce scratches and wear due to scratches and friction during use, resulting in poor wear resistance, which affects the application fields of MS resin.

[0003] In the prior art, the improvement of the wear resistance of MS resin is mainly focused on the modification of raw materials during the preparation process of MS resin itself and the additional addition of auxiliary materials to improve wear resistance during the preparation process. Patent CN103044833B discloses a glass fiber reinforced MS composite material and a preparation method thereof. The invention uses MS resin, glass fiber, compatibilizer, liquid water, antioxidant, and lubricant as formulation components, and then during the melt extrusion process, uses glass fiber for synergistic modification. By adjusting the content of glass fiber, the strength and toughness of the glass fiber reinforced MS composite material can be adjusted and controlled, thereby improving the mechanical strength and toughness of MS resin.

[0004] Patent CN114479297B discloses a high impact resistance and wear-resistant transparent polystyrene composition, a preparation method thereof, and an application thereof. Polystyrene, styrene-butadiene block copolymer, styrene-methyl methacrylate copolymer, and styrene-maleic anhydride copolymer are mixed and extruded into pellets to obtain a high impact resistance and wear-resistant transparent polystyrene composition. The invention selects and matches the raw material components at the initial stage of preparation to improve the performance of the prepared composition.

[0005] Modifying the raw materials for preparing MS resin materials to improve the wear resistance of MS resin materials is also a treatment method. However, since the raw material formula of MS resin is improved, the chemical properties of different components of raw materials are different. Although mixing and polymerizing these components can improve the wear resistance, since the composition structure of MS resin itself has been changed, it may cause changes in the deep structure inside the MS resin material, which may cause adverse changes such as a decrease in the light transmittance and hardness of the MS resin material itself, making the MS resin unable to be better applied.

[0006] Therefore, designing a wear-resistant coating, by attaching the wear-resistant coating to the surface of MS resin, avoiding affecting the deep structure inside the MS resin and causing a decrease in light transmittance and hardness, and thus improving the wear resistance of MS resin, is of great significance. Summary of the Invention

[0007] According to the deficiencies of the prior art, the present invention synthesizes a polysiloxane with carbon-carbon double bonds from a double-bond silane compound and an epoxy-group silane compound, and then introduces carboxylic acid groups into the side chain of the polysiloxane through a free-radical addition reaction between the carbon-carbon double bonds and mercapto carboxylic acid. The obtained carboxylated polysiloxane is combined with MS resin through the coordination of copper ions. During the synthesis of the polysiloxane, due to the catalytic action of the alkaline environment, the epoxy group is ring-opened to generate hydroxyl groups, and the hydroxyl groups and carboxyl groups on the surface of the MS resin treated by plasma are condensed and esterified to form covalent bonds, finally obtaining a wear-resistant coating for MS resin, which solves the problems in the background technology. Specifically, the technical solution of the present invention includes the following content:

[0008] A preparation method of a wear-resistant coating for MS resin, the preparation method comprising the following steps:

[0009] Mix and dissolve a double-bond silane compound and an epoxy-group silane compound in an aqueous solution of tetrahydrofuran, and then add hydrochloric acid for acidification to obtain a silicon hydroxyl mixture;

[0010] The silicon hydroxyl mixture and a weak base are mixed and condensed in a mass ratio of 1:0.1 - 0.2 to obtain a polysiloxane;

[0011] The polysiloxane and mercapto carboxylic acid are mixed in a mass ratio of 1:3, and are catalyzed by an initiator at 70°C - 80°C for 3h - 5h to obtain a carboxylated polysiloxane;

[0012] The carboxylated polysiloxane and a copper sulfate solution are mixed and stirred in a mass ratio of 1:1 to form a coating solution;

[0013] The MS resin is quickly immersed in the coating solution after being pretreated by oxygen plasma and then pulled up, and then cured to obtain the wear-resistant coating for MS resin.

[0014] Further, the double-bond silane compound includes γ-methacryloxypropyltrimethoxysilane or tetramethyldivinyldisiloxane.

[0015] Further, the epoxy-group silane compound includes γ-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane or 3-glycidoxypropyltriethoxysilane.

[0016] Further, the mass ratio of the double-bond silane compound: epoxy-group silane compound: aqueous tetrahydrofuran solution is 1:1:2 - 4.

[0017] Further, the conditions for hydrochloric acid acidification include an acidification pH of 3 - 4, an acidification temperature of 20°C - 30°C, and an acidification time of 40 min - 70 min.

[0018] Further, the weak base includes sodium carbonate or sodium bicarbonate.

[0019] Further, the conditions for the mixed condensation include a condensation temperature of 50°C - 80°C and a condensation time of 1 h - 2 h.

[0020] Further, the mercapto carboxylic acid includes mercaptoacetic acid or 3-mercaptopropionic acid.

[0021] Further, the initiator includes azobisisobutyronitrile or methyl ethyl ketone peroxide.

[0022] Further, the mass percentage concentration of the copper sulfate solution is 0.5% - 1%. Although copper chloride can provide copper ions, due to the Lewis acid catalytic effect of copper chloride, it is likely to cause hydrolysis of the polysiloxane structure and affect the stability of the wear-resistant coating structure.

[0023] Further, the plasma pretreatment includes an O2 plasma gas, a treatment power of 800 W - 1000 W, a treatment distance of 20 mm - 30 mm, and a treatment time of 60 s - 150 s.

[0024] Further, the curing includes thermal curing or ultraviolet curing.

[0025] Further, the conditions for thermal curing include a curing temperature of 70°C - 80°C and a curing time of 2 h - 3 h. The conditions for ultraviolet curing include an ultraviolet lamp power of 500 W - 600 W, a treatment of 10 min - 20 min, and a treatment distance of 5 cm - 10 cm.

[0026] A wear-resistant coating prepared by a preparation method for a wear-resistant coating of MS resin.

[0027] An application of a wear-resistant coating in the field of surface protection of MS resin.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] In the present invention, a silane compound containing a carbon-carbon double bond is mixed with a silane compound containing an epoxy group, and then, in an acidic environment, the silyl group is hydrolyzed to form a mixture containing silanol groups. The silanol group mixture forms siloxyanions under the catalysis of an alkaline environment. The siloxyanions, as nucleophiles, attack the silicon atom in the silanol compound and then dehydrate and condense to form a cross-linked structure of siloxane bonds (Si-O-Si), and finally polysiloxane is obtained. The epoxy group in the polysiloxane is ring-opened in an alkaline environment to form a hydroxyl structure. At this time, the polysiloxane undergoes a radical addition reaction with mercapto carboxylic acid through the carbon-carbon double bond under the catalysis of an initiator, thereby introducing a carboxylic acid structure into the polysiloxane to obtain a carboxylated polysiloxane. After the MS resin is pretreated by plasma with oxygen as the gas source, oxygen-containing groups such as hydroxyl groups and carboxyl groups are obtained on the surface of the MS resin. The carboxylated polysiloxane forms a cross-linked structure with multiple oxygen-containing groups on the plasma-pretreated MS resin through the metal coordination of copper ions. The carboxylated polysiloxane condenses with the carboxylic acid groups on the plasma-pretreated MS resin through hydroxyl groups to form a covalent cross-linked structure. The synergistic cooperation among the metal coordination, the covalent cross-linking, and the hydrogen bonds formed by the plasma pretreatment increases the adhesion between the wear-resistant coating and the MS resin without completely destroying the deep structure of the MS resin, improves the wear resistance of the MS resin, and the good optical properties of the polysiloxane itself improve the light transmittance of the wear-resistant coating cured on the MS resin. Specific embodiments

[0030] The technical solutions of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Unless otherwise specified, the raw materials and reagents used in the present invention below are all commercially available products or can be prepared by known methods.

[0032] Example 1:

[0033] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0034] Weigh 300 g of γ-methacryloxypropyltrimethoxysilane and 300 g of γ-glycidoxypropyltrimethoxysilane and place them together in a three-necked flask. Then add 600 g of a tetrahydrofuran aqueous solution (composed of 240 g of tetrahydrofuran and 360 g of deionized water) and mix and stir them until evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 3. Place the acid-adjusted dispersion in a water bath environment at 20 °C and time the acidification treatment for 40 min. After removing tetrahydrofuran by vacuum evaporation, a hydrolyzed silanol mixture is obtained;

[0035] Take 200 g of the hydrolyzed silanol mixture and mix and stir it with 20 g of sodium carbonate and place it in a water bath environment at 50 °C for reaction for 1 h. After the reaction is completed, add water, stir and separate to obtain polysiloxane;

[0036] Weigh 100 g of polysiloxane and dissolve it in 300 mL of tetrahydrofuran. Mix and stir 300 g of mercaptoacetic acid and 6 g of azobisisobutyronitrile, and place it in a temperature environment of 70 °C and time the reaction for 3 h. After the reaction is completed, remove tetrahydrofuran by vacuum evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a copper sulfate solution with a mass percentage concentration of 0.5% to the carboxylated polysiloxane solution, mix and stir for 30 min, and then let it stand for 20 h to obtain a coating solution;

[0037] Clean the MS resin with an ultrasonic cleaner, remove the surface moisture, and put it into a plasma device. Control the distance between the MS resin and the nozzle to be 20 mm. Use oxygen as the plasma treatment gas, treat it at a power of 800 W for 60 s, and then completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 min. Pull it up at a speed of 20 cm / min until the MS resin is completely pulled out. After the MS resin is completely pulled out, cure it in an environment of 70 °C for 2 h and naturally cool it to room temperature to obtain a wear-resistant coating.

[0038] Example 2:

[0039] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0040] Weigh 300 g of γ-methacryloxypropyltrimethoxysilane and 300 g of 3-glycidoxypropylmethyldiethoxysilane and place them together in a three-necked flask. Then add 800 g of a tetrahydrofuran aqueous solution (composed of 350 g of tetrahydrofuran and 450 g of deionized water) and mix and stir them until evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 3. Place the acid-adjusted dispersion in a water bath environment at 20 °C and time the acidification treatment for 40 min. After removing tetrahydrofuran by vacuum evaporation, a hydrolyzed silanol mixture is obtained;

[0041] Take 200 g of the hydrolyzed silanol mixture and mix it with 20 g of sodium carbonate, stir well, and place it in a water bath at 50 °C for 1 h. After the reaction, add water, stir, and separate to obtain polysiloxane;

[0042] Weigh 100 g of polysiloxane and dissolve it in 300 mL of tetrahydrofuran. Mix 300 g of mercaptoacetic acid and 6 g of azobisisobutyronitrile, stir well, and place it in a temperature environment of 70 °C for 3 h. After the reaction, remove tetrahydrofuran by vacuum evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a copper sulfate solution with a mass percentage concentration of 0.5% to the carboxylated polysiloxane solution, stir well for 30 min, and then let it stand for 20 h to obtain a coating solution;

[0043] Clean the MS resin with an ultrasonic cleaner, remove the surface moisture, and put it into a plasma device. Control the distance between the MS resin and the nozzle to be 20 mm. Use oxygen as the plasma treatment gas, treat it at a power of 800 W for 80 s, and then completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 min. Pull it up at a speed of 20 cm / min until the MS resin is completely pulled out. After the MS resin is completely pulled out, cure it in an environment of 70 °C for 3 h, and then naturally cool it to room temperature to obtain a wear-resistant coating.

[0044] Example 3:

[0045] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0046] Weigh 300 g of γ-methacryloxypropyltrimethoxysilane and 300 g of 3-glycidoxypropyltriethoxysilane and place them together in a three-necked flask. Then add 800 g of a tetrahydrofuran aqueous solution (composed of 350 g of tetrahydrofuran and 450 g of deionized water), mix and stir until evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 3.5. Place the acid-adjusted dispersion in a water bath at 25 °C and time the acidification treatment for 50 min. Remove tetrahydrofuran by vacuum evaporation to obtain a hydrolyzed silanol mixture;

[0047] Take 200 g of the hydrolyzed silanol mixture and mix it with 30 g of sodium carbonate, stir well, and place it in a water bath at 60 °C for 1 h. After the reaction, add water, stir, and separate to obtain polysiloxane;

[0048] Weigh 100 g of polysiloxane and dissolve it in 300 mL of tetrahydrofuran. Mix 300 g of mercaptoacetic acid and 6 g of azobisisobutyronitrile, stir well, and place it in a temperature environment of 70 °C for 4 h. After the reaction, remove tetrahydrofuran by vacuum evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a copper sulfate solution with a mass percentage concentration of 0.5% to the carboxylated polysiloxane solution, stir well for 30 min, and then let it stand for 20 h to obtain a coating solution;

[0049] After cleaning the MS resin with an ultrasonic cleaner, remove the surface moisture and place it in a plasma device. Control the distance between the MS resin and the nozzle to be 25 mm. Using oxygen as the plasma treatment gas, after treating for 100 s at a power of 900 W, completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 minute. Pull it up to the MS resin at a speed of 20 cm / min. After the MS resin is completely pulled out, cure it in an environment of 80 °C for 3 h, and then naturally cool it to room temperature to obtain a wear-resistant coating.

[0050] Example 4:

[0051] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0052] Weigh 300 g of tetramethyldivinyldisiloxane and 300 g of γ-glycidoxypropyltrimethoxysilane and place them together in a three-necked flask. Then add 1000 g of a tetrahydrofuran aqueous solution (composed of 400 g of tetrahydrofuran and 600 g of deionized water) and mix and stir them until evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 3.5. Place the acid-adjusted dispersion in a water bath environment at 25 °C and time the acidification treatment for 50 min. Remove tetrahydrofuran by vacuum evaporation to obtain a hydrolyzed silanol mixture.

[0053] Take 200 g of the hydrolyzed silanol mixture and mix and stir it with 30 g of sodium bicarbonate and place it in a water bath environment at 70 °C for reaction for 2 h. After the reaction, add water and stir to separate to obtain polysiloxane.

[0054] Weigh 100 g of polysiloxane and dissolve it in 300 mL of tetrahydrofuran. Mix and stir 300 g of 3-mercaptopropionic acid and 6 g of methyl ethyl ketone peroxide, place it in a temperature environment of 80 °C and time the reaction for 4 h. After the reaction, remove tetrahydrofuran by vacuum evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a 1% copper sulfate solution by mass percentage to the carboxylated polysiloxane solution, mix and stir for 30 min, and then let it stand for 20 h to obtain a coating solution.

[0055] After cleaning the MS resin with an ultrasonic cleaner, remove the surface moisture and place it in a plasma device. Control the distance between the MS resin and the nozzle to be 25 mm. Using oxygen as the plasma treatment gas, after treating for 120 s at a power of 900 W, completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 minute. Pull it up to the MS resin at a speed of 20 cm / min. After the MS resin is completely pulled out, place it directly below 5 cm away from the ultraviolet lamp, and then treat it at a power of 500 W for 10 min to obtain a wear-resistant coating.

[0056] Example 5:

[0057] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0058] Weigh 300 g of tetramethyldivinyldisiloxane and 300 g of 3-glycidoxypropylmethyldiethoxysilane and place them together in a three-necked flask. Then add 1000 g of a tetrahydrofuran aqueous solution (composed of 400 g of tetrahydrofuran and 600 g of deionized water) and mix and stir them until evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 4. Place the acid-adjusted dispersion in a water bath environment at 30 °C and time the acidification treatment for 70 min. After removing tetrahydrofuran by vacuum evaporation, a hydrolyzed silanol mixture is obtained;

[0059] Take 200 g of the hydrolyzed silanol mixture and mix and stir it with 40 g of sodium bicarbonate and place it in a water bath environment at 80 °C for reaction for 2 h. After the reaction ends, add water and stir to separate to obtain polysiloxane;

[0060] Weigh 100 g of polysiloxane and dissolve it in 300 mL of tetrahydrofuran. Mix and stir 300 g of 3-mercaptopropionic acid and 6 g of methyl ethyl ketone peroxide, place it in a temperature environment of 80 °C and time the reaction for 5 h. After the reaction ends, remove tetrahydrofuran by vacuum evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a 1% copper sulfate solution by mass percentage to the carboxylated polysiloxane solution and mix and stir for 30 min, and then let it stand for 20 h to obtain a coating solution;

[0061] After cleaning the MS resin with an ultrasonic cleaner to remove surface moisture and putting it into a plasma device, control the distance between the MS resin and the nozzle to be 30 mm. Use oxygen as the plasma treatment gas, treat it at a power of 1000 W for 140 s, and then completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 min. Pull it up to the MS resin at a speed of 20 cm / min. After the MS resin is completely pulled out, place it directly below 7 cm away from the ultraviolet lamp, and then treat it at a power of 550 W for 15 min to obtain a wear-resistant coating.

[0062] Example 6:

[0063] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0064] Weigh 300 g of tetramethyldivinyldisiloxane and 300 g of 3-glycidoxypropyltriethoxysilane and place them together in a three-necked flask. Then add 1200 g of a tetrahydrofuran aqueous solution (composed of 500 g of tetrahydrofuran and 700 g of deionized water) and mix and stir them until they are evenly dispersed. Then add hydrochloric acid dropwise to adjust the pH value of the dispersion to 4. Place the acid-adjusted dispersion in a water bath environment at 30 °C and time the acidification treatment for 70 min. After removing tetrahydrofuran by reduced pressure evaporation, a hydrolyzed silanol mixture is obtained.

[0065] Take 200 g of the hydrolyzed silanol mixture and mix and stir it with 40 g of sodium bicarbonate, and place it in a water bath environment at 80 °C to react for 2 h. After the reaction is completed, add water and stir to separate to obtain polysiloxane.

[0066] Weigh 100 g of polysiloxane and dissolve it with 300 mL of tetrahydrofuran. Mix and stir 300 g of 3-mercaptopropionic acid and 6 g of methyl ethyl ketone peroxide, and place it in a temperature environment of 80 °C and time the reaction for 5 h. After the reaction is completed, remove tetrahydrofuran by reduced pressure evaporation to obtain a carboxylated polysiloxane solution. Add an equal mass of a 1% copper sulfate solution by mass percentage to the carboxylated polysiloxane solution and mix and stir for 30 min, and then let it stand for 20 h to obtain a coating solution.

[0067] Clean the MS resin with an ultrasonic cleaner, remove the surface moisture, and put it into a plasma device. Control the distance between the MS resin and the nozzle to be 30 mm. Use oxygen as the plasma treatment gas, and after treating for 150 s at a power of 1000 W, completely immerse the plasma-pretreated MS resin in the coating solution within no more than 1 min, and pull it up at a speed of 20 cm / min until the MS resin is completely pulled out. Then place it directly below a UV lamp at a distance of 10 cm, and then treat it at a power of 600 W for 20 min to obtain a wear-resistant coating.

[0068] Comparative Example 1:

[0069] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0070] Replace 3-mercaptopropionic acid in Example 6 with 2-mercaptobenzoic acid, and keep the other conditions the same as in Example 6.

[0071] Comparative Example 2:

[0072] A preparation method for a wear-resistant coating for MS resin specifically includes the following process:

[0073] Replace the copper sulfate solution in Example 6 with a copper chloride solution (the solvent for dissolving copper chloride is ammonia water), and keep the other conditions the same as in Example 6.

[0074] Comparative Example 3:

[0075] A preparation method for a wear-resistant coating for MS resin, specifically including the following process:

[0076] Replace the tetramethyldivinyldisiloxane in Example 6 with γ-aminopropyltriethoxysilane, and keep the other conditions the same as in Example 6.

[0077] Comparative Example 4:

[0078] A preparation method for a wear-resistant coating for MS resin, specifically including the following process:

[0079] Replace the 3-glycidoxypropyltriethoxysilane in Example 6 with 3-mercaptopropyltriethoxysilane, and keep the other conditions the same as in Example 6.

[0080] Comparative Example 5:

[0081] A preparation method for a wear-resistant coating for MS resin, specifically including the following process:

[0082] Remove the plasma pretreatment process step in Example 6, and keep the other conditions the same as in Example 6.

[0083] Comparative Example 6:

[0084] A preparation method for a wear-resistant coating for MS resin, specifically including the following process:

[0085] Increase the power of the plasma pretreatment of MS resin in Example 6 to 1200 W, shorten the treatment distance to 10 mm, and extend the treatment time to 300 s, and keep the other conditions the same as in Example 6.

[0086] Measure the hardness, adhesion, and light transmittance of the MS resin, the wear-resistant coatings obtained in Examples 1 to 6, and Comparative Examples 1 to 6 according to "GB / T 6739-2022 Paints and varnishes - Determination of film hardness by pencil test", "GB / T 9286-2021 Paints and varnishes - Cross-cut test", and "GB / T 2410 2008 Plastics - Determination of light transmittance and haze of transparent plastics", and the results are shown in Table 1 below.

[0087] Table 1 Performance of Wear-Resistant Coatings

[0088]

[0089]

[0090] The wear-resistant coatings obtained in Examples 1-6 and Comparative Examples 1-6 were uniformly rubbed 100 times at the same speed with 600# sandpaper loaded with a 100 g weight. Weighing was carried out at the 20th, 50th, and 100th times, and the total cumulative wear weight was calculated. The results are shown in Table 2 below.

[0091] Table 2 Wear Resistance Test of Wear-Resistant Coatings

[0092]

[0093]

[0094] It can be seen from the above results that:

[0095] (1) It can be seen from Examples 1-6 that in the present invention, through the free radical addition reaction of carbon-carbon double bonds and mercapto carboxylic acids, carboxylic acid groups are introduced into the side chains of polysiloxanes. The obtained carboxylated polysiloxanes are combined through the coordination of copper ions with MS resin. During the synthesis of polysiloxanes, due to the catalytic action of the alkaline environment, the epoxy groups are ring-opened to generate hydroxyl groups, and the hydroxyl groups and carboxyl groups on the surface of the MS resin after plasma treatment are condensed and esterified to form covalent bonds. Finally, the wear-resistant coatings for MS resin obtained have good light transmittance, hardness, adhesion, and wear resistance.

[0096] (2) It can be seen from Comparative Example 1 that perhaps due to the influence of the electron-withdrawing effect of the carboxyl group on the benzene ring on the mercapto group of 2-mercaptobenzoic acid, the reaction activity of the mercapto group is relatively low, and the steric hindrance effect of the benzene ring may further reduce the reaction activity of the mercapto group, increasing the difficulty of polysiloxane carboxylation. Therefore, the metal coordination effect generated by copper ions is greatly reduced, resulting in a relatively low adhesion of the wear-resistant coating finally cured on the MS resin, poor bonding, and low wear resistance, mechanical properties, and light transmittance.

[0097] (3) It can be seen from Comparative Example 2 that perhaps due to the relatively low coordination number of cuprous chloride, and cuprous chloride is prone to form a coordination structure with ammonia water after being dissolved in ammonia water, further weakening the metal coordination effect between cuprous ions and polysiloxanes and plasma-pretreated MS resin, resulting in a relatively low adhesion of the wear-resistant coating finally cured on the MS resin, poor bonding, and low wear resistance, mechanical properties, and light transmittance.

[0098] (4) It can be seen from Comparative Example 3 that since γ-aminopropyltriethoxysilane does not have a carbon-carbon double bond structure, it may lead to the inability to undergo an addition reaction with 3-mercaptopropionic acid, and finally the plasma-pretreated MS resin and the coating liquid cannot form a metal coordination effect, further reducing the adhesion of the wear-resistant coating, and the wear resistance, mechanical properties, and light transmittance are poor.

[0099] (5) It can be seen from Comparative Example 4 that since 3-mercaptopropyltriethoxysilane does not contain a reactive functional group hydroxyl, it may cause the carboxylated polysiloxane to be unable to form a covalent bond crosslink with the MS resin having a carboxylic acid group after plasma pretreatment. Depending only on hydrogen bonding and metal coordination, the adhesion of the wear-resistant coating on the MS resin is reduced, and the light transmittance, mechanical properties, and wear resistance are also reduced to a certain extent.

[0100] (6) It can be seen from Comparative Example 5 that since the surface of the MS resin is not treated by plasma, there are no reactive groups on the MS resin that can form covalent crosslinks with the carboxylated polysiloxane, and the hydrogen bond force between the MS resin and the wear-resistant coating is reduced, reducing the adhesion of the wear-resistant coating on the MS resin, and the light transmittance, mechanical properties, and wear resistance are also reduced to a certain extent.

[0101] (7) It can be seen from Comparative Example 6 that due to long-term high-intensity plasma pretreatment, the surface roughness of the MS resin may increase, and damages such as cracks may appear, weakening the mechanical properties of the MS resin, reducing the light transmittance of the MS resin, and affecting the optical properties.

[0102] The above-described embodiments have detailed the technical solutions and beneficial effects of the present invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method for an abrasion-resistant coating for MS resin, characterized in that, The preparation method comprises the following steps: Mix a double-bond silane compound and an epoxy-group silane compound and dissolve them in an aqueous solution of tetrahydrofuran, and then add hydrochloric acid for acidification to obtain a silanol mixture; Mix and condense the silanol mixture and a weak base in a mass ratio of 1:0.1-0.2 to obtain a polysiloxane; Mix the polysiloxane and a mercapto-carboxylic acid in a mass ratio of 1:3, and catalyze them with an initiator at 70°C - 80°C for 3h - 5h to obtain a carboxylated polysiloxane; Mix the carboxylated polysiloxane and a copper sulfate solution in a mass ratio of 1:1 and stir to form a coating solution; The MS resin is rapidly immersed in the coating solution after plasma pretreatment and then pulled up, and then cured to obtain the wear-resistant coating for the MS resin.

2. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, characterized in that, The double-bond silane compound includes γ-methacryloxypropyltrimethoxysilane or tetramethyldivinyldisiloxane.

3. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, wherein, The epoxy-group silane compound includes γ-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane or 3-glycidoxypropyltriethoxysilane.

4. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, characterized in that, The mass ratio of the double-bond silane compound: the epoxy-group silane compound: the aqueous solution of tetrahydrofuran is 1:1:2 - 4.

5. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, wherein, The conditions for the hydrochloric acid acidification include an acidification pH of 3 - 4, an acidification temperature of 20°C - 30°C, and an acidification time of 40min - 70min.

6. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, characterized in that, The conditions for the mixing and condensation include a condensation temperature of 50°C - 80°C and a condensation time of 1h - 2h.

7. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, characterized in that, The mercapto-carboxylic acid includes mercaptoacetic acid or 3-mercaptopropionic acid.

8. The preparation method of an abrasion-resistant coating for MS resin according to claim 1, characterized in that, The initiator includes azobisisobutyronitrile or methyl ethyl ketone peroxide.

9. A wear-resistant coating prepared by the preparation method of a wear-resistant coating for an MS resin according to any one of claims 1 - 8.

10. An application of the wear-resistant coating according to claim 9 in the field of surface protection of MS resins.

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