A waterborne two-component solid color topcoat resistant to lead marks and a preparation method thereof

Abstract

The application discloses an anti-lead mark water-based two-component solid color topcoat and a preparation method thereof. The topcoat comprises an A component and a B component. The A component comprises the following raw materials in mass fractions: 55-65 parts of water-based acrylic emulsion, 0.4-0.6 parts of defoaming agent, 3-5 parts of film-forming aid, 0.1-0.2 parts of wetting agent, 1-1.2 parts of thickening agent, 0.8-1.2 parts of matt powder, 0.8-1.2 parts of hand feel aid, 18-22 parts of white paste, 10-15 parts of deionized water, 2-3 parts of wear-resistant agent and 4-6 parts of modified POSS composite material. The B component comprises the following raw materials in mass fractions: 75-85 parts of water-based isocyanate curing agent, 18-22 parts of environment-friendly solvent and 0.1-0.3 parts of water absorption agent. The modified POSS composite material contains amino groups and hydroxyl groups, can participate in and strengthen the establishment of a crosslinking structure of a system and is helpful to the enhancement of the wear resistance and the anti-lead mark resistance of the topcoat.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water-based topcoat, in particular to a water-based two-component solid-color topcoat resistant to lead marks and a preparation method thereof. BACKGROUND

[0002] With the continuous enhancement of environmental awareness, water-based topcoat gradually occupies the market. Among them, water-based solid-color topcoat is applied in different occasions such as furniture coating due to its good hiding power, which plays a role in decoration and protection of objects from being damaged. At the same time, the comprehensive performance of two-component water-based topcoat is also improved to a certain extent compared with that of single-component water-based topcoat because it is chemically formed.

[0003] However, some metal tools or metal parts used in the furniture assembly process often leave a black mark on the paint film surface when they contact the paint film surface, which is called lead mark, which seriously affects the appearance of the finished product and causes the finished product to be of poor quality. There are few records about solid-color topcoat resistant to lead marks on the market. SUMMARY

[0004] To solve the problem that metal objects often leave lead marks on the surface of the paint film, thereby affecting the appearance of the finished product, the present application provides a water-based two-component solid-color topcoat resistant to lead marks and a preparation method thereof.

[0005] In a first aspect, the present application provides a water-based two-component solid-color topcoat resistant to lead marks, comprising component A and component B, wherein the component A and the component B respectively comprise the following raw materials in mass fraction:

[0006] Component A:

[0007] Water-based acrylic emulsion 55-65 parts;

[0008] Defoaming agent 0.4-0.6 parts;

[0009] Film-forming aid 3-5 parts;

[0010] Wetting agent 0.1-0.2 parts;

[0011] Thickening agent 1-1.2 parts;

[0012] Mat powder 0.8-1.2 parts;

[0013] Touch aid 0.8-1.2 parts;

[0014] White paste 18-22 parts;

[0015] Deionized water 10-15 parts;

[0016] Wear-resistant agent 2-3 parts;

[0017] Modified POSS composite material 4-6 parts;

[0018] B component:

[0019] Waterborne isocyanate curing agent 75-85 parts;

[0020] Environment-friendly solvent 18-22 parts;

[0021] Water absorption agent 0.1-0.3 parts;

[0022] The modified POSS composite material contains amino and hydroxyl groups.

[0023] Preferably, the defoaming agent includes one or a combination of several of gas phase silica-containing polyether siloxane, gas phase silica-containing polysiloxane.

[0024] Preferably, the film-forming aid includes one or several of dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether.

[0025] Preferably, the wetting agent is a silicone gemini surfactant.

[0026] Preferably, the thickening agent is a non-ionic associated polyurethane thickening agent.

[0027] Preferably, the hand feel aid is a modified polysiloxane compound.

[0028] Preferably, the environment-friendly solvent is ethylene glycol diacetate.

[0029] Preferably, the water absorption agent is an ester-modified water absorption agent.

[0030] By using the above technical solution, POSS, i.e. cage-type polyhedral oligomeric silsesquioxane, is a nanomaterial containing organic-inorganic hybrid core-shell structure, and the R group contained on its surface is amino and hydroxyl, which has good compatibility with waterborne acrylic emulsion and can be uniformly dispersed in the waterborne acrylic emulsion. The cage structure also makes the structure of the POSS material stable, and can keep the properties of the waterborne acrylic emulsion from being destroyed.

[0031] The water-based two-component solid color topcoat uses deionized water as the medium, and the amino groups in the modified POSS composite can gradually form hydrogen bonds with the hydroxyl groups in the water-based acrylic emulsion with the participation of deionized water, tightly combine with the molecular segments in the water-based acrylic emulsion, participate in and strengthen the establishment of the crosslinking structure of the system, help to improve the toughness of the system, increase the gloss of the surface, and enhance the wear resistance of the topcoat, while protecting the rigid particles such as silica in the system, so that they are not easy to fall off and leave lead marks when encountering metal tools. And the modified POSS composite also contains hydroxyl groups, which can chemically react with the isocyanate groups in component B during the construction process to form a crosslinking structure, enhance the stability of the modified POSS composite in the system, and increase the crosslinking density of the system, thereby enhancing the lead mark resistance of the obtained solid color topcoat.

[0032] Preferably, the water-based acrylic emulsion includes a water-based polyurethane acrylic emulsion and a water-based hydroxyl acrylic emulsion in a mass ratio of (0.1-0.3):1.

[0033] By adopting the above technical solution, the water-based polyurethane acrylic emulsion has high molecular weight and high glass transition temperature, has high weather resistance and solvent resistance, and can complete physical drying at room temperature before chemical crosslinking reaction occurs after mixing with the water-based isocyanate curing agent in component B, which can significantly improve the construction efficiency. However, the compatibility between the water-based polyurethane acrylic emulsion and the water-based isocyanate curing agent is poor, so that the paint film formed by the obtained solid color topcoat does not meet the corresponding appearance requirements, and the water-based polyurethane acrylic emulsion is also prone to water phase nucleation reaction. The distribution of the hydroxyl groups contained therein is uneven, the wrapping of the powder in the topcoat is poor, the pot life of the paint film is greatly shortened, and when the tool scratches the surface of the paint film, the uneven arrangement of the powder of the paint film leaves lead marks. Although the curing time of the water-based hydroxyl acrylic emulsion is slow, the addition of the water-based hydroxyl acrylic emulsion can well regulate the distribution of the hydroxyl groups in the water-based polyurethane acrylic emulsion, thereby enhancing the stability of the water-based acrylic emulsion, facilitating the reaction of the isocyanate groups in component B to form a urethane polymer, increasing the crosslinking density of the paint film, thereby increasing the wear resistance of the paint film, improving the lead mark resistance of the topcoat, and greatly enhancing the adhesion of the topcoat to the substrate.

[0034] The polar groups contained in the modified POSS composite can form hydrogen bonds with the waterborne polyurethane acrylic emulsion and the waterborne hydroxyl acrylic emulsion after the two waterborne acrylic emulsions are mixed, thereby enhancing the crosslinking network structure between the two, improving the cohesive strength and powder wrapping property of the waterborne acrylic emulsion, and further improving the wear resistance and hardness of the topcoat and greatly improving the lead mark resistance; meanwhile, the addition of the modified POSS composite is also conducive to enhancing the chain movement of the polymer chain segment at the molecular level, improving the glass transition temperature of the mixed waterborne acrylic emulsion, making up for the defect of slow curing of the waterborne hydroxyl acrylic emulsion, and meanwhile maintaining the excellent performance of the mixed waterborne polyurethane acrylic solution.

[0035] Preferably, the wear-resistant agent comprises one or a combination of several of nano-aluminum oxide and glass powder.

[0036] By adopting the technical scheme, one important reason for the metal tool leaving lead marks on the paint film surface is that the wear resistance and scratch resistance of the paint film are poor. The wear-resistant agent such as nano-aluminum oxide or glass powder can significantly improve the wear resistance of the topcoat and can improve the wear resistance of the paint film to a certain extent, but still cannot effectively prevent the metal tool from leaving lead marks, and the particles contained in the paint film will also fall off during the scratching process, thereby causing the wear resistance of the paint film to decrease. The arm of the cage structure of the added modified POSS composite contains modified amino or hydroxyl groups, which can further react with the hydroxyl groups on the surface of the wear-resistant agent, fix the wear-resistant agent particles, make the wear-resistant agent enter the crosslinking network structure of the waterborne acrylic emulsion, and improve the wear resistance without easily falling off. The uniform distribution of the particles also improves the gloss of the formed paint film.

[0037] Preferably, the raw material of the modified POSS composite comprises cage-type octavinylsilsesquioxane, hydroxypropyl acrylate and acrylamide in a mass ratio of (0.02-0.04):(0.5-1):1.

[0038] Preferably, the preparation method of the modified POSS composite is as follows: after the POSS is added to the solvent and ultrasonically dispersed for 10-20 min, an initiator is added, the temperature is increased to 60-80℃, and stirring and mixing are performed for 5-10 min to obtain a mixed solution; the acrylamide and the hydroxypropyl acrylate are dissolved in deionized water, then are added dropwise to the obtained mixed solution, and the pH value of the solution is adjusted to 7-8, and stirring is performed for 3-4 h to obtain the modified POSS composite.

[0039] Preferably, the initiator comprises one or a combination of several of sodium persulfate and sodium bisulfite; and the addition amount of the initiator is 1.5%-2.5% of the mass of the acrylamide.

[0040] Preferably, the solvent is a 5% mass fraction of tetrahydrofuran aqueous solution; the mass ratio of the solvent to the cage octavinylsilsesquioxane is (4-4.5):0.01.

[0041] By adopting the technical scheme, the modified POSS composite material containing amino and hydroxyl groups with a multi-side chain structure is obtained by using cage octavinylsilsesquioxane, acrylamide and hydroxypropyl acrylate as raw materials and through a free radical polymerization method. The modified cage octavinylsilsesquioxane has good compatibility with the water-based acrylic emulsion, can be uniformly dispersed in the water-based acrylic emulsion as a nano filler, and increases the hardness and toughness of the finish. The amino and hydroxyl groups can form a crosslinked network structure with the hydroxyl groups contained in the water-based acrylic emulsion, thereby enhancing the cohesive strength and crosslinking density of the water-based acrylic emulsion. The addition of the hydroxyl groups also increases the hydroxyl content in the A component. When mixed with the B component, the hydroxyl groups can react with the isocyanate groups and form a crosslinked structure with the B component, thereby increasing the crosslinking density of the formed paint film, preventing the powder in the finish from falling off and being uniformly distributed, and preventing lead marks from being left on the paint film when the paint film is scratched by a tool.

[0042] Preferably, the A component, the B component and water in the finish are in a mass ratio of 100:(8-12):(8-12).

[0043] In a second aspect, the application further provides a preparation method of the water-based two-component solid-color finish resistant to lead marks, which is prepared according to the following method:

[0044] Preparation of the A component: add a defoaming agent and the modified POSS composite material to the water-based acrylic emulsion, stir and mix at a speed of 400-600 rpm for 10-20 min, and adjust the pH value of the solution to 7-9 to obtain a premix A; uniformly mix a film-forming aid, a wetting agent, part of deionized water and part of a thickening agent, and then add them to the premix A, and disperse at a speed of 800-1000 rpm for 20-30 min to obtain a premix B; add dead powder and wear-resistant agent to the premix B, and disperse at a speed of 1000-1200 rpm for 20-30 min to obtain a premix C; add a hand feel aid, the remaining amount of thickening agent, white paste and the remaining amount of deionized water to the obtained premix C, and stir and mix at a speed of 500-700 rpm for 10-20 min to obtain the A component.

[0045] Preparation of the B component: add the water-based isocyanate curing agent to the environmentally friendly solvent, stir and disperse at a speed of 600-800 rpm for 20-30 min, and then add a water absorption agent, adjust the speed to 400-600 rpm, and stir and disperse for 10-20 min to obtain the B component.

[0046] Preferably, the pH adjusting agent used to adjust the pH of the solution during preparation of the A component includes one or a combination of several of triethanolamine, isobutanolamine.

[0047] In summary, the present application has the following advantages:

[0048] 1. The aqueous acrylic emulsion used in the present application is a mixed emulsion of aqueous polyurethane acrylic and aqueous hydroxy acrylic, wherein the aqueous polyurethane acrylic can compensate for the slow curing speed of the aqueous hydroxy acrylic emulsion, and the aqueous hydroxy acrylic emulsion can compensate for the uneven arrangement of hydroxyl groups in the aqueous polyurethane acrylic emulsion, facilitating the reaction of the aqueous polyurethane acrylic emulsion with the isocyanate groups in the B component to form a urethane polymer, increasing the crosslinking density of the paint film, thereby increasing the wear resistance of the paint film and improving the lead mark resistance of the topcoat.

[0049] 2. The A component of the present application also adds a modified POSS composite material containing amino and hydroxyl groups. On the one hand, in the presence of deionized water as a medium, the modified POSS composite material can form a crosslinked network structure with the aqueous acrylic emulsion, increasing the cohesive strength and powder wrapping property of the aqueous acrylic emulsion, thereby improving the wear resistance and hardness of the topcoat and greatly improving the lead mark resistance, while also increasing the glass transition temperature of the aqueous acrylic emulsion and accelerating the curing process. On the other hand, the modified POSS composite material can further react with the hydroxyl groups on the surface of the wear-resistant agent, fixing the wear-resistant agent particles and allowing the wear-resistant agent to enter the crosslinked network structure of the aqueous acrylic emulsion, thereby improving wear resistance without easily falling off, with uniform particle distribution effectively preventing uneven powder arrangement of the paint film and leaving lead marks when the tool scratches the paint film surface. DETAILED DESCRIPTION

[0050] Preparation Example of Modified POSS Composite Material

[0051] Preparation Example 1: A modified POSS composite material was prepared according to the following method:

[0052] 3g of cage-type octavinylsilsesquioxane (purity 99%) was added to 12.6g of a 5% mass fraction tetrahydrofuran aqueous solution and ultrasonically dispersed for 10min, then 2g of sodium persulfate was added and the temperature was raised to 80℃, and the mixture was stirred for 10min to obtain a mixed solution;

[0053] 100g of acrylamide and 70g of hydroxypropyl acrylate were dissolved in 500ml of deionized water, then added dropwise to the obtained mixed solution, and the pH of the solution was adjusted to 7.5, and the reaction was stirred for 4h to obtain the modified POSS composite material.

[0054] Preparation Example 2, a modified POSS composite, differs from Preparation Example 1 only in that the amount of cage-type octavinylsilsesquioxane added is 2 g and the amount of 5% by mass tetrahydrofuran aqueous solution added is 8.4 g.

[0055] Preparation Example 3, a modified POSS composite, differs from Preparation Example 1 only in that the amount of cage-type octavinylsilsesquioxane added is 4 g and the amount of 5% by mass tetrahydrofuran aqueous solution added is 16.8 g.

[0056] Preparation Example 4, a modified POSS composite, differs from Preparation Example 1 only in that the amount of hydroxypropyl acrylate added is 50 g.

[0057] Preparation Example 5, a modified POSS composite, differs from Preparation Example 1 only in that the amount of hydroxypropyl acrylate added is 100 g.

[0058] Preparation Example 6, a modified POSS composite, differs from Preparation Example 1 only in that the amount of cage-type octavinylsilsesquioxane added is 1 g and the amount of 5% by mass tetrahydrofuran aqueous solution added is 4.2 g.

[0059] Preparation Example 7, a modified POSS composite, differs from Preparation Example 1 only in that the amount of cage-type octavinylsilsesquioxane added is 5 g and the amount of 5% by mass tetrahydrofuran aqueous solution added is 21 g.

[0060] Preparation Example 8, a modified POSS composite, differs from Preparation Example 1 only in that no hydroxypropyl acrylate is added.

[0061] Preparation Example 9, a modified POSS composite, differs from Preparation Example 1 only in that no acrylamide is added.

[0062] Example

[0063] Example 1, a lead mark resistant water-based two-component solid color topcoat, was prepared by separately preparing the A component and the B component according to the following methods.

[0064] Preparation of A component: 60 g of water-based acrylic emulsion was added with defoaming agent of BYK022 type and 5 g of modified POSS composite prepared in Preparation Example 1, and stirred at a speed of 500 rpm for 20 min, and then pH regulator of AMP-95 type was added to adjust the pH value of the solution to 8 to obtain a premix A; 4 g of dipropylene glycol monomethyl ether, 0.15 g of wetting agent of TEGO4100 type, 5 g of deionized water and 0.2 g of non-ionic associated polyurethane thickener of RM-2050D type were uniformly mixed and then added to the premix A, and dispersed at a speed of 1000 rpm for 20 min to obtain a premix B; 1 g of matt powder and 2.5 g of nano-alumina were added to the premix B, and dispersed at a speed of 1000 rpm for 30 min to obtain a premix C; 1 g of hand feel aid of DC51 type, 0.9 g of non-ionic associated polyurethane thickener of RM-2050D type, 20 g of white paste (the white paste contains 75% of R706 titanium white paste) and 7 g of deionized water were sequentially added to the obtained premix C, and stirred at a speed of 600 rpm for 15 min to obtain the A component;

[0065] Preparation of B component: 80 g of water-based isocyanate curing agent of Bayhydur305 type was added to 20 g of ethylene glycol diacetate, and stirred and dispersed at a speed of 800 rpm for 30 min, and then water absorption agent of BF-5 type was added, and the stirring speed was adjusted to 500 rpm, and stirred and dispersed for 20 min to obtain the B component.

[0066] The water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion (of Epoxy U9900 type) and water-based hydroxyl acrylic emulsion (of Epoxy AC8892 type) with a mass ratio of 0.2:1.

[0067] Examples 2-9, a water-based two-component solid color finish resistant to lead marks, which is different from Example 1 in that the raw materials and their proportions used in the A component and the B component are adjusted, and the specific adjustments can be shown in Table 1:

[0068] Table 1 Formulation table of A component and B component

[0069]

[0070]

[0071] The water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion (of Epoxy U9900 type) and water-based hydroxyl acrylic emulsion (of Epoxy AC8892 type) with a mass ratio of 0.2:1.

[0072] Example 2 and Example 3 use the modified POSS composite prepared in Preparation Example 2; Example 4 uses the modified POSS composite prepared in Preparation Example 3; Example 5 uses the modified POSS composite prepared in Preparation Example 4; Example 6 and Example 7 use the modified POSS composite prepared in Preparation Example 5; Example 8 and Example 9 use the modified POSS composite prepared in Preparation Example 1.

[0073] Example 10, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion and water-based hydroxyl acrylic emulsion at a mass ratio of 0.1:1.

[0074] Example 11, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion and water-based hydroxyl acrylic emulsion at a mass ratio of 0.3:1.

[0075] Example 12, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the modified POSS composite prepared in Preparation Example 1 is replaced with an equal amount of the modified POSS composite prepared in Preparation Example 6.

[0076] Example 13, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the modified POSS composite prepared in Preparation Example 1 is replaced with an equal amount of the modified POSS composite prepared in Preparation Example 7.

[0077] Example 14, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion and water-based hydroxyl acrylic emulsion at a mass ratio of 0.05:1.

[0078] Example 15, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a mixed emulsion of water-based polyurethane acrylic emulsion and water-based hydroxyl acrylic emulsion at a mass ratio of 0.4:1.

[0079] Example 16, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a water-based hydroxyl acrylic emulsion.

[0080] Example 17, a water-based two-component solid color topcoat resistant to lead marks, differs from Example 1 only in that the water-based acrylic emulsion used in the A component is a water-based polyurethane acrylic emulsion.

[0081] Comparative Example

[0082] Comparative Example 1, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that the amount of the modified POSS composite prepared in Preparation Example 1 added is 3 g.

[0083] Comparative Example 2, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that the amount of the modified POSS composite prepared in Preparation Example 1 added is 8 g.

[0084] Comparative Example 3, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that the modified POSS composite prepared in Preparation Example 8 is used instead of the modified POSS composite prepared in Preparation Example 1.

[0085] Comparative Example 4, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that the modified POSS composite prepared in Preparation 9 is used instead of the modified POSS composite prepared in Preparation Example 1.

[0086] Comparative Example 5, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that the unmodified cage-type octavinylsilsesquioxane is used instead of the modified POSS composite prepared in Preparation Example 1.

[0087] Comparative Example 6, a waterborne two-component solid color topcoat resistant to lead mark, differs from Example 1 only in that no modified POSS composite prepared in Preparation Example 1 is added.

[0088] Performance test

[0089] 1. Hardness test: The test was performed according to GB / T 6739-2006 "Standard Test Methods for Paint Film Hardness by Pencil" as the standard. The test results are shown in Table 2.

[0090] 2. Abrasion resistance test: The test was performed according to GB / T 1768-2006 "Standard Test Methods for Paint Film Abrasion Resistance by Rotating Rubber Wheel" as the standard. The test results are shown in Table 2.

[0091] 3. Lead mark resistance test: The test sample was prepared according to GB / T 9271-2008 "Standard Test Panels for Paints and Varnishes". Then, a steel plate was used to simulate the phenomenon of being scratched by a metal tool in reality on the sample, and the lead mark formed on the paint film was recorded. The results were divided into five grades, in which 5 represents that the black mark left is very obvious, 4 represents that the black mark left is obvious, 3 represents that the black mark left, 2 represents that the black mark left is slightly, and 1 represents that no black mark is left. The test results are shown in Table 2.

[0092] In the test process, the A component: B component: water = 100: 10: 10.

[0093] Table 2: Results of each performance test

[0094]

[0095] According to Table 2, in combination with Example 1 and Examples 2-9, it can be seen that the hardness of Examples 2-9 is the same as that of Example 1, i.e., 2H, the mass of wear in the wear resistance test does not change significantly compared with Example 1, and the lead mark resistance grade is the same as that of Example 1, indicating that the hardness, wear resistance and lead mark resistance of Examples 2-9 do not change significantly compared with Example 1. The reason may be that the modified POSS composite and the ratio of each raw material of the two-component topcoat in Examples 2-9 are changed, indicating that changing the ratio of raw materials within the required range has no significant effect on the performance of the solid color topcoat obtained.

[0096] In combination with Example 1, Example 10 and Example 11, it can be seen that the hardness of Examples 10 and 11 is the same as that of Example 1, i.e., 2H, the mass of wear in the wear resistance test does not change significantly compared with Example 1, and the lead mark resistance grade is the same as that of Example 1, indicating that the hardness, wear resistance and lead mark resistance of Examples 10 and 11 do not change significantly compared with Example 1. The reason may be that the composition ratio of the water-based acrylic emulsion used in component A in Examples 10 and 11 is changed within the required range, indicating that changing the mass ratio of the water-based polyurethane acrylic emulsion and the water-based hydroxyl acrylic emulsion within the required range has no significant effect on the performance of the solid color topcoat obtained.

[0097] In combination with Example 1, Example 12 and Example 13, the hardness of Examples 12 and 13 is the same as that of Example 1, i.e., 2H, the mass of wear in the wear resistance test decreases slightly compared with Example 1, and the lead mark resistance grade decreases compared with Example 1, indicating that the wear resistance and lead mark resistance of Examples 12 and 13 decrease compared with Example 1. The reason may be that in the preparation process of the modified POSS composite, the amount of cage-type octavinylsilsesquioxane added in Example 12 is reduced, resulting in a decrease in the amount of effective modified POSS composite obtained, a decrease in the cross-linked structure in the solid color topcoat, a decrease in cross-linking density, and a decrease in wear resistance and lead mark resistance; in the preparation process of the modified POSS composite, the amount of cage-type octavinylsilsesquioxane added in Example 13 is increased, which easily causes agglomeration during preparation, resulting in a decrease in the amount of effective modified POSS composite obtained, and a decrease in the wear resistance and lead mark resistance of the topcoat obtained.

[0098] Compared with Example 1 and Examples 14-17, the hardness of Examples 14-17 is reduced, the mass of abrasion in the abrasion resistance test is reduced, and the lead mark resistance grade of Examples 16 and 17 is reduced, indicating that the hardness, abrasion resistance and lead mark resistance of Examples 14-17 are all reduced compared with Example 1. The reason may be that the amount of waterborne polyurethane acrylic emulsion in Examples 14 and 16 is reduced or not added, and the waterborne polyurethane acrylic emulsion can enhance the hardness of the topcoat and the crosslinking between the modified POSS composite material, and the reduction of the waterborne polyurethane acrylic emulsion will reduce the hardness of the obtained topcoat; the amount of waterborne hydroxyl acrylic emulsion in Examples 15 and 17 is reduced or not added, and the addition of waterborne hydroxyl acrylic emulsion is to adjust the hydroxyl content in the system and make up for the problem of uneven arrangement of hydroxyl groups in the waterborne polyurethane acrylic emulsion, and the lack of hydroxyl acrylic emulsion will reduce the hardness, abrasion resistance and corresponding lead mark resistance of the obtained topcoat.

[0099] Compared with Example 1, Comparative Example 1 and Comparative Example 2, the hardness of Comparative Example 1 is reduced, the mass of abrasion in the abrasion resistance test of Comparative Examples 1 and 2 is reduced, and the lead mark resistance grade of Comparative Examples 1 and 2 is reduced, indicating that the hardness, abrasion resistance and lead mark resistance of Comparative Examples 1 and 2 are all reduced compared with Example 1. The reason may be that the amount of modified POSS composite material in Comparative Example 1 is reduced, so the amount of POSS material crosslinked with waterborne acrylic emulsion and waterborne isocyanate curing agent in the system is reduced, the crosslinking density is reduced, and the abrasion resistance and lead mark resistance of the obtained topcoat are reduced; the amount of modified POSS composite material in Comparative Example 2 is increased, and the amount of small molecule substances is increased, which is easy to agglomerate, and the crosslinking effect is reduced, and the abrasion resistance and lead mark resistance of the obtained topcoat are reduced.

[0100] Compared with Example 1, Comparative Example 3 and Comparative Example 4, it can be seen that the hardness of Comparative Example 3 and Comparative Example 4 is decreased compared with Example 1, the mass of wear and tear in the wear resistance test of Comparative Example 3 and Comparative Example 4 is decreased compared with Example 1, and the lead mark resistance grade of Comparative Example 3 and Comparative Example 4 is decreased compared with Example 1, indicating that the hardness, wear resistance and lead mark resistance of Comparative Example 3 and Comparative Example 4 are all decreased compared with Example 1. The reason may be that the modified POSS composite material used in Comparative Example 3 does not contain hydroxyl groups because no hydroxypropyl acrylate is added during preparation. On the one hand, hydroxyl groups can form hydrogen bonds with components in the topcoat, increasing crosslinking density. On the other hand, the addition of hydroxyl groups increases crosslinking with waterborne isocyanate curing agents, increasing overall crosslinking density. Without the action of hydroxyl groups, the wear resistance and lead mark resistance of the topcoat are decreased. The modified POSS composite material used in Comparative Example 4 does not contain amino groups because no acrylamide is added during preparation. Amino groups can form hydrogen bonds with hydroxyl groups in the waterborne acrylic emulsion, increasing crosslinking density. Without the action of amino groups, the crosslinking structure is decreased, and the wear resistance and lead mark resistance of the obtained topcoat are decreased.

[0101] Compared with Example 1, Comparative Example 5 and Comparative Example 6, it can be seen that the hardness of Comparative Example 5 and Comparative Example 6 is decreased compared with Example 1, the mass of wear and tear in the wear resistance test of Comparative Example 5 and Comparative Example 6 is significantly decreased compared with Example 1, and the lead mark resistance grade of Comparative Example 5 and Comparative Example 6 is significantly decreased compared with Example 1, indicating that the hardness, wear resistance and lead mark resistance of Comparative Example 5 and Comparative Example 6 are all significantly decreased compared with Example 1. The reason may be that the modified POSS composite material used in Comparative Example 5 is not modified by hydroxypropyl acrylate and acrylamide, and the surface does not contain hydroxyl groups or amino groups. The crosslinking density between the waterborne acrylic emulsion and the modified POSS composite material is significantly decreased, the cohesive strength and powder encapsulation of the waterborne acrylic emulsion are decreased, and there is no further defect in the curing process. As a result, the wear resistance and hardness of the obtained topcoat and the lead mark resistance are significantly decreased. In Comparative Example 6, no modified POSS composite material is added, and there is no crosslinking effect of polar groups, and no filling effect of POSS itself, which can increase the performance of the topcoat to a certain extent. Therefore, the hardness, wear resistance and lead mark resistance of the topcoat in Comparative Example 6 are all significantly decreased.

[0102] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A waterborne two-component solid color topcoat resistant to lead marks, characterized in that, Comprise A component and B component, the A component and B component respectively comprise the following mass fraction of raw materials: A component: Water-based acrylic emulsion 55~65 parts; Defoaming agent 0.4~0.6 parts; Film forming aid 3~5 parts; Wetting agent 0.1~0.2 parts; Thickening agent 1~1.2 parts; Mat powder 0.8~1.2 parts; Hand feel aid 0.8~1.2 parts; White paste 18~22 parts; Deionized water 10~15 parts; Wear-resistant agent 2~3 parts; Modified POSS composite 4~6 parts; B component: Water-based isocyanate curing agent 75~85 parts; Environment-friendly solvent 18~22 parts; Water absorption agent 0.1~0.3 parts; The water-based acrylic emulsion is a mixed emulsion of water-based polyurethane acrylic emulsion and water-based hydroxyl acrylic emulsion with a mass ratio of (0.1~0.3):1; The modified POSS composite contains amino and hydroxyl groups; the preparation method of the modified POSS composite is as follows: after adding cage-type octavinylsilsesquioxane to a solvent and ultrasonic dispersion for 10~20 min, an initiator is added, the temperature is raised to 60~80 DEG C, and stirring mixing is carried out for 5~10 min to obtain a mixed solution; acrylamide and hydroxypropyl acrylate are dissolved in deionized water, then are added dropwise into the obtained mixed solution, and the solution pH value is adjusted to 7~8, and stirring reaction is carried out for 3~4 h to obtain the modified POSS composite; wherein the mass ratio of the cage-type octavinylsilsesquioxane, hydroxypropyl acrylate and acrylamide is (0.02~0.04):(0.5~1):

1.

2. The lead-resistant waterborne two-component solid color topcoat according to claim 1, characterized in that The defoaming agent comprises one or a combination of several of polyether siloxane containing fumed silica, polysiloxane containing fumed silica.

3. The lead-resistant waterborne two-component solid color topcoat according to claim 1, characterized in that, The film forming aid comprises one or several of dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether.

4. The lead-resistant waterborne two-component solid color topcoat according to claim 1, characterized in that, The wear-resistant agent is nano alumina.

5. The lead-resistant waterborne two-component solid color topcoat according to claim 1, characterized in that, The initiator comprises one or a combination of several of sodium persulfate, sodium bisulfite; the addition amount of the initiator is 1.5%~2.5% of the mass of acrylamide.

6. The lead-resistant waterborne two-component solid color topcoat according to claim 1, characterized in that, The A component:B component:water in the finish =100:(8~12):(8~12).

7. The method for preparing a waterborne two-component solid color topcoat resistant to lead marks according to any one of claims 1 to 6, characterized in that, Preparation is obtained according to the following method: Preparation of A component: add defoaming agent and modified POSS composite into water-based acrylic emulsion, stirring mixing is carried out for 10~20 min under the speed of 400~600 rpm, and the solution pH value is adjusted to 7~9 to obtain premix A; mix film forming aid, wetting agent, part of deionized water and part of thickening agent uniformly, then add into premix A, and disperse for 20~30 min under the speed of 800~1000 rpm to obtain premix B; add mat powder and wear-resistant agent into premix B, and disperse for 20~30 min under the speed of 1000~1200 rpm to obtain premix C; add hand feel aid, thickening agent balance, white paste and deionized water balance into the obtained premix C in sequence, and stirring mixing is carried out for 10~20 min under the speed of 500~700 rpm to obtain A component; Preparation of B component: add the waterborne isocyanate curing agent into the environmentally friendly solvent, stir and disperse at 600-800 rpm for 20-30 min, then add the water absorbent, adjust the stirring speed to 400-600 rpm, stir and disperse for 10-20 min to obtain the B component.

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