Two-component condensation type rapid matte coating and preparation method thereof

Abstract

The invention belongs to the technical field of coatings, and particularly relates to a two-component condensed type rapid matte coating and a preparation method thereof, and the two-component condensed type rapid matte coating comprises a component A and a component B, the component A is prepared from the following preparation raw materials in parts by weight: 50 to 70 parts of alpha, omega-dihydroxy polydimethylsiloxane, 10 to 20 parts of modified nano silicon dioxide, 5 to 15 parts of a plasticizer, 0.1 to 1 part of a catalyst and 0.1 to 2 parts of an auxiliary agent; the component B is prepared from the following raw materials in parts by weight: 40 to 60 parts of alkoxy-terminated polydimethylsiloxane, 5 to 15 parts of a mixed cross-linking agent, 1 to 5 parts of a coupling agent, 2 to 10 parts of a delustering agent and 0.2 to 2 parts of a stabilizer. By adjusting the formula, the formula has the advantages of high curing speed, strong adhesive force, uniform and stable glossiness and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of coatings, and in particular relates to a two-component condensation-type fast matte coating and a preparation method thereof. Background Art

[0002] As people's expectations for product appearance continue to rise, matte coatings are gaining increasing attention and application due to their unique visual effects and texture. Traditional matte coatings often suffer from slow curing, poor adhesion, and unstable gloss. For example, a method for preparing fluorescent matte silicone is currently available. The method involves placing 50-70 parts of α,ω-dihydroxypolydimethylsiloxane, 10-30 parts of filler, 5-20 parts of plasticizer, 1-10 parts of pigment, and 0.1-1.5 parts of fluorescent brightener in a planetary stirred tank and heating and dehydrating at 110-120°C for 2 hours. After cooling, 5-10 parts of a mixed crosslinker are added and stirred for 15 minutes. 0.5-1.5 parts of a coupling agent and 0.05-0.2 parts of a catalyst are then added and stirred for 20 minutes before discharging. The matte coating in this technical solution uses tung oil. Due to its volatility and instability, tung oil loses its effectiveness after storage due to volatilization and oxidation, resulting in unstable product performance. This method struggles to meet the high efficiency and high quality requirements of modern industrial production. Summary of the Invention

[0003] The purpose of the present invention is to provide a two-component condensation-type fast matte coating and a preparation method thereof, aiming to solve the technical problems of slow curing speed, poor adhesion and unstable gloss in the prior art.

[0004] To achieve the above objectives, the present invention provides a two-component condensation-type fast matte coating and a preparation method thereof, comprising a component A and a component B; the component A comprises the following raw materials in parts by weight: 50-70 parts of α,ω-dihydroxypolydimethylsiloxane, 10-20 parts of modified nano-silica, 5-15 parts of a plasticizer, 0.1-1 part of a catalyst, and 0.1-2 parts of an auxiliary agent, wherein the modified nano-silica is surface-treated with an organic silane coupling agent;

[0005] The B component comprises the following raw materials in parts by weight: 40-60 parts of alkoxy-terminated polydimethylsiloxane, 5-15 parts of a mixed crosslinking agent, 1-5 parts of a coupling agent, 2-10 parts of a matting agent, and 0.2-2 parts of a stabilizer; the mixed crosslinking agent is a mixture of methyltrimethoxysilane, ethyl orthosilicate, and octyltrimethoxysilane.

[0006] The modified nano-silica is surface treated with an organic silane coupling agent as follows: the first step is to dry the nano-silica, dry it at a high temperature to remove physically adsorbed water, and avoid the subsequent hydrolysis failure of the organic silane coupling agent; the second step is to dissolve the organic silane coupling agent in an anhydrous ethanol solution, and the ratio of the organic silane coupling agent to the anhydrous ethanol solution is 1:7-9; the nano-silica is added to the mixed solution, and the mixture is stirred in a planetary mixer at a stirring speed of 200 to 500 rpm for 1 to 2 hours, and then baked until the anhydrous ethanol solution is completely volatilized, and the remaining solid matter is collected to obtain modified nano-silica treated with an organic silane coupling agent. The organic silane coupling agent is preferably silazane. The surface of the nano-silica is treated with an organic silane coupling agent, which can effectively improve the compatibility with polydimethylsiloxane, better disperse together, and will not agglomerate, which plays a key role in the matte effect of the coating.

[0007] Optionally, the modified nano-silica has a particle size of 10-50 nm; the organically modified nano-SiO2 with a particle size of 10-50 nm is treated with a surface organic silane (such as silazane) and can be uniformly dispersed in α, ω-dihydroxy polydimethylsiloxane. After curing, the nanoparticles form a submicron-scale concave-convex structure near the surface of the coating, scattering short-wave light (visible light band), directly contributing to the matte effect. At the same time, the nanoparticles enhance the hardness, wear resistance and tear resistance of the coating through physical filling and surface chemical bonding (Si-O-Si network).

[0008] Optionally, the matting agent is silica powder surface-treated with an organic silane coupling agent, and the processing steps of the silica powder are the same as those of the modified nano-silica.

[0009] Optionally, the particle size of the silicon dioxide powder is 1-5 μm. The SiO powder with a particle size of 1-5 μm quickly migrates to the surface during the coating curing, forming a macroscopic concave-convex structure, scattering long-wave light, and achieving an instant matte effect.

[0010] Optionally, the mixed crosslinking agent is prepared by mixing methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane. The mixed crosslinking agent can undergo a condensation reaction with the hydroxyl group in component A to form a stable three-dimensional network structure, thereby improving the curing speed, adhesion and wear resistance of the coating.

[0011] Specifically, the mixing mass ratio of methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane is 4-5:3-4:3-4, and the preferred ratio is 4:3:3.

[0012] Optionally, the catalyst is one or a mixture of an organotin catalyst, an organotitanium catalyst, and an amine catalyst. This can accelerate the condensation reaction, allowing the coating to cure rapidly at room temperature. Specifically, the organotin catalyst can be Fomrez UL-28; the organotitanium catalyst can be selected from Guangzhou Wanjun Chemical Technology Co., Ltd.; and the amine catalyst can be selected from allnex CYCAT296-10.

[0013] Optionally, the stabilizer is a metal carboxylate or an organosilazane. Zinc naphthenate can be selected as the metal carboxylate to inhibit the side reaction between the curing agent and the hydroxyl groups on the surface of silica through chelation, thereby preventing the matting agent from becoming ineffective or increasing the gloss of the coating. Hexamethyldisilazane can be selected as the organosilazane to improve the dispersion stability of the matting agent and prevent agglomeration during storage.

[0014] Optionally, the auxiliary agent is one or a mixture of a leveling agent, a defoaming agent, and an antioxidant. The leveling agent may be TEGO FloW 300; the defoaming agent may be KS-360 from Kasong Chemical; and the antioxidant may be Irganox 1010.

[0015] Optionally, the plasticizer is one of dimethyl silicone oil, hydroxy-terminated polydimethylsiloxane and dioctyl phthalate. The coupling agent is a silane coupling agent, and KH-550 can be selected.

[0016] Optionally, the two-component condensation-type fast matte coating and its preparation method include the following steps:

[0017] S1 Preparation of Component A:

[0018] According to the formula, α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, and additives in component A are weighed separately and added into a reaction kettle. The mixture is stirred and mixed at 60-80°C for 30-60 minutes to fully disperse the components. The temperature is then lowered to 40-50°C, a catalyst is added, and stirring is continued for 10-20 minutes. The mixture is discharged to obtain component A.

[0019] S2 prepares component B:

[0020] According to the formula, the alkoxy-terminated polydimethylsiloxane, mixed crosslinking agent, coupling agent, matting agent and stabilizer in component B are weighed separately and added into the reaction kettle. The mixture is stirred and mixed at 50-70° C. for 40-80 minutes to ensure that the components are fully dispersed and evenly distributed. The mixture is discharged to obtain component B.

[0021] Optionally, when used, component A and component B are mixed in a mass ratio of 1:1 and then can be used for application.

[0022] The present invention provides a two-component condensation-type fast matte coating and a preparation method thereof, which have at least the following technical effects: the modified nano-silica described in component A in the formula, whose surface is treated with an organic silane coupling agent, can effectively improve the compatibility with polydimethylsiloxane, and at the same time plays a key role in the matte effect of the coating. The matting agent can form a micro-rough structure on the surface of the coating to achieve a fast matte effect. The mixed cross-linking agent is prepared by mixing methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane. The above-mentioned mixed cross-linking agent can undergo a condensation reaction with the hydroxyl group in component A to form a stable three-dimensional network structure, thereby improving the curing speed, adhesion and wear resistance of the coating. By adjusting the formula, the prepared matte coating can meet the advantages of fast curing speed, strong adhesion, uniform and stable glossiness, etc. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the examples, but the embodiments of the present invention are not limited thereto.

[0024] Preparation Example 1 Preparation of modified nano-silica

[0025] The preparation of modified nano-silica includes the following steps:

[0026] S11, drying the nano-silica at a temperature of 100-120° C. to remove physically adsorbed water and prevent subsequent hydrolysis and failure of the organic silane coupling agent;

[0027] S12. Dissolve the silazane coupling agent in anhydrous ethanol solution, with the ratio of the silazane coupling agent to the anhydrous ethanol solution being 1:9; then add the dried nano-silica to the mixed solution, place it in a planetary mixer and stir at a speed of 200-500 rpm for 1-2 hours, then bake until the anhydrous ethanol solution is completely evaporated, collect the remaining solid matter, and the remaining solid matter is modified nano-silica treated with the silazane coupling agent.

[0028] Preparation Example 2 Preparation of mixed cross-linking agent

[0029] The preparation of the mixed cross-linking agent comprises the following steps:

[0030] S21, weigh methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane in a mass ratio of 4:3:3,

[0031] S22. Pour the weighed methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane into a stirring bucket respectively and stir them until evenly mixed to obtain the mixed cross-linking agent.

[0032] Preparation Example 3 Preparation of matting agent

[0033] The preparation of the matting agent comprises the following steps:

[0034] S31, drying the silica powder at a temperature of 100-120° C. to remove physically adsorbed water and prevent subsequent hydrolysis and ineffectiveness of the organosilane coupling agent;

[0035] S32. Dissolve the silazane coupling agent in anhydrous ethanol solution, with the ratio of the silazane coupling agent to the anhydrous ethanol solution being 1:9; then add silica powder to the mixture, place it in a planetary mixer for stirring, and then bake to evaporate the anhydrous ethanol solution and collect it. The remaining silica powder treated with the silazane coupling agent is obtained, that is, the matting agent.

[0036] Example 1

[0037] A two-component condensation-type fast matte coating, comprising component A and component B; component A comprises the following raw materials in parts by weight: 60 parts of α,ω-dihydroxypolydimethylsiloxane, 15 parts of modified nano-silica, 10 parts of plasticizer, 0.5 parts of catalyst, and 1 part of auxiliary agent;

[0038] Component B comprises the following raw materials in parts by weight: 50 parts of alkoxy-terminated polydimethylsiloxane, 10 parts of mixed cross-linking agent, 3 parts of coupling agent, 5 parts of matting agent, and 1 part of stabilizer.

[0039] The particle size of the modified nano-silica is 30 nm; the catalyst is Fomrez catalyst UL-28; the matting agent is silica micropowder surface-treated with an organic silane coupling agent; the particle size of the silica micropowder is 3 μm; the mixed cross-linking agent is prepared by mixing methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane in a mass ratio of 4:3:3; the stabilizer is zinc cyclohexane; the auxiliary agents include a leveling agent selected from TEGO FloW 300 and a defoaming agent selected from KS-360 of Kasong Chemical; the plasticizer is dimethyl silicone oil; and the coupling agent is a silane coupling agent KH-550.

[0040] A two-component condensation-type fast matte coating and a preparation method thereof, comprising the following steps:

[0041] S1 Preparation of Component A:

[0042] According to the formula, α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, catalyst, and additives in component A are weighed respectively; the weighed α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, and additives are added to the reaction kettle, stirred and mixed at 60°C for 60 minutes to fully and evenly disperse the components, then cooled to 40°C, added the catalyst, continued stirring for 20 minutes, and discharged to obtain component A.

[0043] S2 prepares component B:

[0044] According to the formula, the alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer in component B are weighed respectively; the weighed alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer are added to a reaction kettle, stirred and mixed at 50° C. for 80 minutes to ensure that the components are fully dispersed, and the material is discharged to obtain component B.

[0045] When in use, mix component A and component B in a mass ratio of 1:1 and then use them for application.

[0046] Example 2

[0047] A two-component condensation-type fast matte coating, comprising component A and component B; component A comprises the following raw materials in parts by weight: 70 parts of α,ω-dihydroxypolydimethylsiloxane, 10 parts of modified nano-silica, 15 parts of a plasticizer, 0.1 parts of a catalyst, and 0.1 parts of an additive;

[0048] Component B comprises the following raw materials in parts by weight: 40 parts of alkoxy-terminated polydimethylsiloxane, 5 parts of mixed cross-linking agent, 1 part of coupling agent, 2 parts of matting agent, and 0.2 parts of stabilizer.

[0049] The particle size of the modified nano-silica is 10 nm; the catalyst is an organic titanium catalyst selected from Guangzhou Wanjun Chemical Technology Co., Ltd.; the matting agent is silica micropowder surface-treated with an organic silane coupling agent; the particle size of the silica micropowder is 5 μm; the mixed cross-linking agent is prepared by mixing methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane in a mass ratio of 4:3:3; the stabilizer is hexamethyldisilazane; the auxiliary agents include a leveling agent selected from TEGO FloW300, a defoaming agent selected from Kasong Chemical KS-360 and an antioxidant selected from Irganox 1010; the plasticizer is terminal hydroxyl polydimethylsiloxane, and the coupling agent is a silane coupling agent KH-550.

[0050] A two-component condensation-type fast matte coating and a preparation method thereof, comprising the following steps:

[0051] S1 Preparation of Component A:

[0052] According to the formula, α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, catalyst, and additives in component A are weighed respectively; the weighed α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, and additives are added to the reaction kettle, stirred and mixed at 70°C for 50 minutes to ensure that the components are fully dispersed, then cooled to 45°C, the catalyst is added, stirring is continued for 15 minutes, and the material is discharged to obtain component A.

[0053] S2 prepares component B:

[0054] According to the formula, the alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer in component B were weighed respectively; the weighed alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer were added to the reaction kettle, stirred and mixed at 60° C. for 60 minutes to ensure that the components were fully dispersed, and the material was discharged to obtain component B.

[0055] When in use, mix component A and component B in a mass ratio of 1:1 and then use them for application.

[0056] Example 3

[0057] A two-component condensation-type fast matte coating, comprising component A and component B; component A comprises the following raw materials in parts by weight: 50 parts of α,ω-dihydroxypolydimethylsiloxane, 20 parts of modified nano-silica, 5 parts of plasticizer, 1 part of catalyst, and 2 parts of additive;

[0058] Component B comprises the following raw materials in parts by weight: 60 parts of alkoxy-terminated polydimethylsiloxane, 15 parts of a mixed cross-linking agent, 5 parts of a coupling agent, 10 parts of a matting agent, and 2 parts of a stabilizer.

[0059] The particle size of the modified nano-silica is 50 nm; the catalyst is an organic titanium catalyst which can be selected from Guangzhou Wanjun Chemical Technology Co., Ltd.; the matting agent is silica micropowder surface-treated with an organic silane coupling agent; the particle size of the silica micropowder is 1 μm; the mixed cross-linking agent is prepared by mixing methyltrimethoxysilane, ethyl orthosilicate and octyltrimethoxysilane in a mass ratio of 4:3:3; the stabilizer is hexamethyldisilazane; the auxiliary agents include a leveling agent selected from TEGO FloW300, a defoaming agent selected from Kasong Chemical's KS-360 and an antioxidant selected from Irganox 1010; the plasticizer is dioctyl phthalate; and the coupling agent is a silane coupling agent KH-550.

[0060] A two-component condensation-type fast matte coating and a preparation method thereof, comprising the following steps:

[0061] S1 Preparation of Component A:

[0062] According to the formula, α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, catalyst, and additives in component A are weighed respectively; the weighed α,ω-dihydroxypolydimethylsiloxane, modified nano-silica, plasticizer, and additives are added to the reaction kettle, stirred and mixed at 80°C for 30 minutes to fully and evenly disperse the components, then cooled to 50°C, added the catalyst, continued stirring for 10 minutes, and discharged to obtain component A.

[0063] S2 prepares component B:

[0064] According to the formula, the alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer in component B were weighed respectively; the weighed alkoxy-terminated polydimethylsiloxane, mixed cross-linking agent, coupling agent, matting agent, and stabilizer were added to the reaction kettle, stirred and mixed at 70° C. for 40 minutes to ensure that the components were fully dispersed, and the material was discharged to obtain component B.

[0065] When in use, mix component A and component B in a mass ratio of 1:1 and then use them for application.

[0066] Comparative Example 1

[0067] The same as Example 1, except that the modified nano-silica in Example 1 is replaced by ordinary nano-silica with the same particle size.

[0068] Comparative Example 2

[0069] The same as Example 1, except that the silica powder surface-treated with an organic silane coupling agent in Example 1 is replaced with ordinary silica powder of the same particle size that is not surface-treated with an organic silane coupling agent.

[0070] Comparative Example 3

[0071] The same as Example 1, except that the mass ratio of methyltrimethoxysilane, tetraethyl orthosilicate and octyltrimethoxysilane in the mixed crosslinking agent in Example 1 is replaced by the mass ratio of methyltrimethoxysilane, tetraethyl orthosilicate and octyltrimethoxysilane in the mixed crosslinking agent in Example 1 being 5:2:3.

[0072] Comparative Example 4

[0073] The same as Example 1, except that the mixed crosslinking agent in Example 1 is replaced by a mixture of methyltrimethoxysilane, ethyl orthosilicate, and octyltrimethoxysilane, with a mass ratio of 6:4.

[0074] Comparative Example 5

[0075] The same as Example 1, except that the mixed cross-linking agent in Example 1 is replaced with methyltrimethoxysilane.

[0076] The coatings prepared in Examples 1-3 and Comparative Examples 1-5 were tested by mixing component A and component B in a weight ratio of 1:1, applying the mixture to a metal plate, and then conducting the following tests:

[0077] Both conventional adhesion and boiling adhesion were tested according to GB / T9286-1998. The boiling adhesion requirement was 85°C for 2 hours (RS). The high-temperature and high-humidity test required 50 cycles of storage at 40°C, 90% RH for 5 hours, followed by 85°C, 80% RH for 5 hours. The curing time standard was in accordance with GB / T 1728-2020. Gloss was measured using a BYK glossmeter at a 60° angle. The following data is shown in Table 1.

[0078] Table 1

[0079]

[0080] By comparing Comparative Examples 1-5 with Example 1, it can be seen that the selection and proportion of the mixed cross-linking agent will affect the curing speed of the coating. The fastest curing speed of the existing matte coatings available on the market is about 3-4 hours, because once the curing speed is too fast, other stability and gloss will be affected. At the same time, it can undergo a condensation reaction with the hydroxyl group in component A to form a stable three-dimensional network structure, thereby improving the adhesion and wear resistance of the coating. Whether the nano-silica and silica powder in the formula are modified or not will affect its matte effect. The modification can effectively improve the compatibility with polydimethylsiloxane, better disperse together, prevent agglomeration, and prevent local uneven roughness and unstable matte effect.

[0081] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A two-component condensation type fast matte coating, characterized in that: The invention comprises component A and component B; component A comprises the following raw materials in parts by weight: 50-70 parts of α,ω-dihydroxypolydimethylsiloxane, 10-20 parts of modified nano-silica, 5-15 parts of plasticizer, 0.1-1 part of catalyst, and 0.1-2 parts of auxiliary agent, wherein the modified nano-silica is prepared by surface treatment with an organic silane coupling agent; The B component comprises the following raw materials in parts by weight: 40-60 parts of alkoxy-terminated polydimethylsiloxane, 5-15 parts of a mixed crosslinking agent, 1-5 parts of a coupling agent, 2-10 parts of a matting agent, and 0.2-2 parts of a stabilizer; the mixed crosslinking agent is a mixture of methyltrimethoxysilane, tetraethyl orthosilicate, and octyltrimethoxysilane, and the mixed mass ratio of the methyltrimethoxysilane, the tetraethyl orthosilicate, and the octyltrimethoxysilane is 4-5:3-4:3-4.

2. The two-component condensation type fast matte paint according to claim 1, characterized in that: The particle size of the modified nano-silica is 10-50 nm.

3. The two-component condensation type fast matte paint according to claim 1, characterized in that: The matting agent is silicon dioxide powder surface-treated with an organic silane coupling agent.

4. The two-component condensation type fast matte paint according to claim 3, characterized in that: The particle size of the silicon dioxide powder is 1-5 μm.

5. The two-component condensation type fast matte paint according to claim 1, characterized in that: The catalyst is one or a mixture of several of an organic tin catalyst, an organic titanium catalyst and an amine catalyst.

6. The two-component condensation type fast matte paint according to claim 1, characterized in that: The stabilizer is a carboxylic acid metal salt or an organosilazane.

7. The two-component condensation type fast matte paint according to claim 1, characterized in that: The auxiliary agent is one or a mixture of several of a leveling agent, a defoaming agent and an antioxidant.

8. The method for preparing a two-component condensation-type fast matte coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1 Preparation of Component A: Weighing α,ω-dihydroxy polydimethylsiloxane, modified nano-silica, plasticizer, catalyst, and additives in component A according to the formula; adding the weighed α,ω-dihydroxy polydimethylsiloxane, modified nano-silica, plasticizer, and additives into a reaction kettle, stirring and mixing at 60-80° C. for 30-60 minutes to fully and evenly disperse the components, then cooling to 40-50° C., adding the catalyst, continuing stirring for 10-20 minutes, and discharging to obtain component A; S2 prepares component B: According to the formula, the alkoxy-terminated polydimethylsiloxane, mixed crosslinking agent, coupling agent, matting agent, and stabilizer in component B are weighed respectively; the weighed alkoxy-terminated polydimethylsiloxane, mixed crosslinking agent, coupling agent, matting agent, and stabilizer are added to the reaction kettle, stirred and mixed at 50-70° C. for 40-80 minutes to ensure that the components are fully and evenly dispersed, and the material is discharged to obtain component B.

9. The method for preparing a two-component condensation-type fast matte coating according to claim 9, characterized in that: When in use, the component A and the component B are mixed in a mass ratio of 1:1 and then can be used for application.

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