A room-temperature curing solvent-free silicone coating material and its application method

Abstract

The present invention relates to the technical field of silicone coatings, and discloses a room-temperature curing solvent-free silicone coating material and an application method thereof. The raw materials include a silicone prepolymer A, a polysiloxane B, a curing agent C, and a pigment and filler D. The silicone prepolymer A is prepared by subjecting a silane compound as a raw material to hydrolysis and polycondensation reactions under acid catalysis, is neutral, has a low viscosity, is solvent-free, and forms a continuous and smooth silicone coating material upon curing at room temperature after reacting with the curing agent C. The polysiloxane B is a silicone oil, a silicone resin, a modified silicone material, etc., and together with the pigment and filler D, endows the silicone coating material with better flexibility, water repellency, oil repellency, scratch resistance and other functions. The silicone coating material of the present invention is green and environmentally friendly, convenient to construct, and stable in storage, and can be used in the fields of surface protection of materials such as concrete, metal, and PCB circuit boards.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone coatings, and particularly to a room-temperature curing solvent-free silicone coating material and an application method thereof. Background Art

[0002] Silicone has basic properties such as low surface tension, small viscosity-temperature coefficient, good compressibility, and high gas permeability, and has excellent properties such as resistance to high and low temperatures, electrical insulation, oxidation stability, weather resistance, flame retardancy, water repellency, corrosion resistance, non-toxic and odorless, and physiological inertness, and is applied in many fields. Silicone coating materials are an application product of silicone in the coating field. After the silicone material system is made into a solution state and coated on the surface of a substrate and then cured, a thin film structure is formed, which has excellent properties such as high hardness, hydrophobicity, corrosion resistance, flame retardancy, and resistance to high and low temperatures.

[0003] Silanol compounds are one of the commonly used raw materials for preparing silicone coating materials at present. They are prepolymers formed by acid-catalyzed hydrolysis and polycondensation of silane compounds in an alcohol aqueous solution. Since the prepolymers contain a large number of groups such as hydroxyl groups and alkoxy groups, condensation reactions can occur between the hydroxyl groups and between the hydroxyl groups and alkoxy groups by heating to form a cured cross-linked structure. Therefore, they play an important role in the fields of coating adhesives and the like. Although silanol compounds have many advantages, the silicone coatings prepared from silanol compounds in the prior art have problems that acid catalysts and alcohol solvents remain in the prepolymers, and they volatilize into the environment during the heating and curing process, which will cause a large amount of VOC emissions and corrosion risks. Therefore, in order to solve this problem, a preparation method of an organosilicon adhesive disclosed in CN109628062A solves the problems caused by alcohols and residual acids by using calcium carbonate to neutralize the acid and removing water and alcohol by distillation, but the application field of this technical solution is adhesives, so this technical solution does not explore the problems that occur when it is applied in the coating field.

[0004] On the basis of the above content, the present invention further studies the problems existing when silanol compounds are applied in the coating field. It is found through research that the viscosity of the prepolymer increases after the alcohol solvent is removed from the silanol compound, resulting in an increase in the coating application processing difficulty and poor coating flatness. In addition, the traditional curing of silanol compounds uses a heating curing method, and the heating temperature exceeds 100 °C. Therefore, it cannot be applied to the surface of substrates with low heat resistance, and there are problems of small application range and high energy consumption. Therefore, in view of the above problems, a room-temperature curing solvent-free silicone coating material is provided. Summary of the Invention

[0005] In order to overcome the problems of high viscosity, high curing temperature and great processing difficulty in the coating field of the silanol compounds for removing alcohol and acid in the prior art, the present invention provides a room-temperature curing solvent-free silicone coating material and an application method thereof. The raw materials of the room-temperature curing solvent-free silicone coating material contain a low-viscosity silicone prepolymer and a curing agent. By adding the curing agent, the silicone prepolymer can be cured at room temperature. At the same time, the low-viscosity silicone prepolymer can reduce the processing difficulty, and the coating is continuous, smooth and has high flatness after room-temperature curing.

[0006] The specific technical solution of the present invention is as follows:

[0007] A room-temperature curing solvent-free silicone coating material, the raw materials include a silicone prepolymer A, a polysiloxane B, a curing agent C and a pigment filler D, and the viscosity of the silicone prepolymer A is 5-100 cst.

[0008] Preferably, the surface drying time of the room-temperature curing solvent-free silicone coating material is ≤60 min, the thickness is ≤20 μm, and the adhesion is ≤2 grades.

[0009] The present invention provides a room-temperature curing solvent-free silicone coating material. The raw materials of the coating material contain a low-viscosity silicone prepolymer and a curing agent. The curing agent can make the silicone prepolymer cure and crosslink at room temperature, significantly reducing the crosslinking temperature of the silicone prepolymer and significantly increasing the application range of the silicone coating material; the low-viscosity silicone prepolymer can reduce the processing difficulty, making the flatness of the silicone coating material formed after its room-temperature curing significantly increase; for the above technical effects, the present invention has found in practical applications that since the traditional silicone prepolymer needs to be cured by heating before it can crosslink and cure to form a silicone coating material, the silicone prepolymer with a relatively high viscosity during the application process can be processed by other processes to form a flat coating and then cured by heating. When the silicone prepolymer with a relatively high viscosity can be cured at room temperature, due to its poor flowability caused by high viscosity, it is difficult to form a silicone coating material with high flatness after room-temperature curing. Therefore, the present invention provides a low-viscosity silicone prepolymer for the above content. The silicone prepolymer has high flowability after coating and can form a continuous, smooth and high-flatness silicone coating material when used for room-temperature curing.

[0010] Preferably, the polysiloxane B includes one or more of silicone oil, silicone resin and modified silicone materials, and the mass ratio of the polysiloxane B to the silicone prepolymer A is 0-0.1:1.

[0011] Preferably, the pigment filler D includes one or several of titanium dioxide, iron oxide red, carbon black and cobalt blue, the particle size of the pigment filler D is ≤20 μm, and the mass ratio of the pigment filler D to the silicone prepolymer A is 0-0.6:1.

[0012] Preferably, the curing agent C includes one or more of organotitanium, organotin and organic bases, and the mass ratio of the curing agent C to the organosilicon prepolymer A is 0.01-0.05:1.

[0013] An application method of the above room-temperature curing solvent-free organosilicon coating material, characterized by comprising the following preparation steps:

[0014] Step 1: Mix a lower alcohol, a silane compound, an acid and water and react to obtain a silanol prepolymer;

[0015] Step 2: Add a carbonate to the product of Step 1, react with the acid and then filter to obtain a deacidified silanol prepolymer;

[0016] Step 3: Perform a desolventization treatment on the deacidified silanol prepolymer in Step 2 to prepare an organosilicon prepolymer A;

[0017] Step 4: Mix the curing agent C, the polysiloxane B, the pigment filler D and the organosilicon prepolymer A in Step 3, coat them on the surface of the substrate and cure at room temperature to prepare a room-temperature curing solvent-free organosilicon coating material.

[0018] Preferably, the reaction conditions in Step 1 include: temperature 50-80°C, time 1-5 h.

[0019] Preferably, the reaction conditions in Step 2 include: stirring, temperature 50-80°C, time 0.5-2 h.

[0020] Preferably, the desolventization treatment conditions in Step 3 include: vacuum pumping, the vacuum degree is less than -0.05 MPa, the vacuum pumping time is 0.5-3 h, and the vacuum pumping temperature is 50-80°C.

[0021] Preferably, the lower alcohol includes one or more of methanol, ethanol and isopropanol; the molar ratio of the lower alcohol to the silane compound is 0.5-5:1;

[0022] The silane compound includes one or more of methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, phenyltriethoxysilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, 3,3,3-trifluoropropylmethylcyclotrisiloxane;

[0023] The acid includes one of hydrochloric acid, sulfuric acid, acetic acid, and trifluoromethanesulfonic acid, and the molar ratio of the acid to the silane compound is 10 -5 ~10 -3 :1;

[0024] The water is deionized water, and the molar ratio of the water to the silane compound is 1-4:1;

[0025] The carbonate includes one or more of sodium bicarbonate, sodium carbonate, and calcium carbonate, and the molar ratio of the carbonate to the acid is 2-5:1.

[0026] The present invention also provides a method for applying the above room-temperature curable solvent-free silicone coating material. In this method, first, a silanol prepolymer is synthesized by controlling the raw material ratio and synthesis process. Then, the residual acid catalyst is neutralized by adding carbonate to achieve the technical effect of acid removal. Next, the residual alcohol in the silanol prepolymer is removed by evaporation and vacuum pumping to achieve the technical effect of solvent removal. The prepared silicone prepolymer is a low-viscosity, solvent-free, acid-free silicone prepolymer. Then, a curing agent is added to the above silicone prepolymer to obtain a room-temperature curable silicone prepolymer. In the present invention, the viscosity range of the silicone prepolymer is limited to be between 5 and 100 cst. The silicone prepolymer within this viscosity range can form a film plane with high adhesion, high hardness, continuous smoothness, and high flatness when preparing the room-temperature curable solvent-free silicone coating material.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] (1) The raw materials in the room-temperature curable solvent-free silicone coating material provided by the present invention include silicone prepolymer A and curing agent C. Among them, silicone prepolymer A is prepared by using a silane compound as a raw material, through acid catalysis, hydrolysis, and polycondensation reactions. Through the adjustment of raw material ratio and process parameters, it is neutral, solvent-free, low-viscosity (5-100 cst), and has good leveling property. After reacting with curing agent C at room temperature, it can quickly (surface drying time ≤ 60 min) form a continuous smooth film layer (≤ 20 μm) with high adhesion (≤ 2 grades).

[0029] (2) The raw materials in the room-temperature curable solvent-free silicone coating material provided by the present invention also include polysiloxane B, which is silicone oil, silicone resin, modified silicone materials, etc. It can be filled in the silicone coating material only physically, or it can react with polysiloxane A under the action of curing agent C, thereby enhancing the toughness, hydrophobicity, oleophobicity, scratch resistance, etc. of the silicone coating. Specific Embodiments

[0030] The present invention will be further described below in conjunction with embodiments.

[0031] Example 1:

[0032] A room-temperature curing solvent-free silicone coating material, the raw materials of which include a silicone prepolymer and a curing agent. The surface drying time of the room-temperature curing solvent-free silicone coating material is 50 min, the thickness is 15 μm, and the adhesion is grade 2;

[0033] An application method of the above-mentioned room-temperature curing solvent-free silicone coating material, comprising the following steps:

[0034] Step 1: Inject lower alcohols (isopropanol), silane compounds (isobutyltrimethoxysilane), acids (acetic acid), and water (deionized water) with a molar ratio of 2:1:10 -5 :3 into a reaction flask, mix them evenly and react to obtain a silanol prepolymer. The reaction conditions include: temperature 75 °C, time 1 h;

[0035] Step 2: Inject sodium bicarbonate (molar ratio to acid is 3:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 75 °C, time 1 h;

[0036] Step 3: Perform a desolventization treatment on the deacidified silanol prepolymer to prepare a silicone prepolymer A (viscosity is 5 cst). The desolventization treatment conditions include: vacuum pumping (vacuum degree is -0.05 MPa), temperature 75 °C, time 2 h;

[0037] Step 4: Mix a curing agent C (tetrabutyl titanate) and the silicone prepolymer A with a mass ratio of 0.05:1, coat them on the surface of the substrate, and cure at room temperature to prepare a room-temperature curing solvent-free silicone coating material.

[0038] Example 2:

[0039] A room-temperature curing solvent-free silicone coating material, the raw materials of which include a silicone prepolymer and a curing agent. The surface drying time of the room-temperature curing solvent-free silicone coating material is 60 min, the thickness is 20 μm, and the adhesion is grade 1;

[0040] An application method of the above-mentioned room-temperature curing solvent-free silicone coating material, comprising the following steps:

[0041] Step 1: Inject lower alcohols (ethanol), silane compounds (methyltriethoxysilane), acids (sulfuric acid), and water (deionized water) with a molar ratio of 0.5:1:10 -3 :4 into a reaction flask, mix them evenly and react to obtain a silanol prepolymer. The reaction conditions include: temperature 80 °C, time 1 h;

[0042] Step 2: Inject calcium carbonate (molar ratio to acid is 4:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 80 °C, time 2 h;

[0043] Step 3: Subject the deacidified silanol prepolymer to solvent removal treatment to obtain organosilicon prepolymer A (viscosity: 10 cst). The solvent removal treatment conditions include: vacuum pumping (vacuum degree: -0.05 MPa), temperature: 80°C, time: 1 h;

[0044] Step 4: Mix a curing agent C (dibutyl dilaurate) and organosilicon prepolymer A at a mass ratio of 0.01:1, then coat the mixture on the surface of the substrate and cure it at room temperature to obtain a room-temperature-curing solvent-free organosilicon coating material.

[0045] Example 3:

[0046] A room-temperature-curing solvent-free organosilicon coating material, the raw materials of which include an organosilicon prepolymer and a curing agent. The surface drying time of the room-temperature-curing solvent-free organosilicon coating material is 50 min, the thickness is 15 μm, and the adhesion is grade 2;

[0047] An application method of the above-mentioned room-temperature-curing solvent-free organosilicon coating material, comprising the following steps:

[0048] Step 1: Inject a lower alcohol (isopropyl alcohol), a silane compound (isobutyltrimethoxysilane), an acid (hydrochloric acid), and water (deionized water) at a molar ratio of 2:1:10 -3 :3 into a reaction flask, mix them evenly, and then react to obtain a silanol prepolymer. The reaction conditions include:

[0049] Temperature: 75°C, time: 1 h;

[0050] Step 2: Inject sodium carbonate (molar ratio to the acid is 3:1) into the silanol prepolymer obtained in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature: 75°C, time: 1 h;

[0051] Step 3: Subject the deacidified silanol prepolymer to solvent removal treatment to obtain organosilicon prepolymer A (viscosity: 10 cst). The solvent removal treatment conditions include: vacuum pumping (vacuum degree: -0.05 MPa), temperature: 75°C, time: 2 h;

[0052] Step 4: Mix a curing agent C (tetrabutyl titanate) and organosilicon prepolymer A at a mass ratio of 0.02:1, then coat the mixture on the surface of the substrate and cure it at room temperature to obtain a room-temperature-curing solvent-free organosilicon coating material.

[0053] Example 4:

[0054] A room-temperature-curing solvent-free organosilicon coating material, the raw materials of which include an organosilicon prepolymer and a curing agent. The surface drying time of the room-temperature-curing solvent-free organosilicon coating material is 40 min, the thickness is 10 μm, and the adhesion is grade 1;

[0055] A method for applying the above room-temperature curable solvent-free silicone coating material, comprising the following steps:

[0056] Step 1: Inject lower alcohol (methanol) with a molar ratio of 5:1:10 -4 :4, silane compound (the mass ratio of methyltrimethoxysilane and dimethyldimethoxysilane is 3:1), acid (trifluoromethanesulfonic acid) and water (deionized water) into a reaction flask, mix well and react to obtain a silanol prepolymer. The reaction conditions include: temperature 60°C, time 4 h;

[0057] Step 2: Inject calcium carbonate (with a molar ratio of 4:1 to the acid) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 60°C, time 2 h;

[0058] Step 3: Perform a desolvation treatment on the deacidified silanol prepolymer to make an organosilicon prepolymer A (viscosity 100 cst). The desolvation treatment conditions include: vacuum pumping (vacuum degree -0.05 MPa), temperature 60°C, time 2 h;

[0059] Step 4: Mix a curing agent C (the mass ratio of tetrabutyl titanate and dibutyltin dilaurate is 1:1) with a mass ratio of 0.05:1 and the organosilicon prepolymer A, and coat it on the surface of the substrate and cure at room temperature to make a room-temperature curable solvent-free silicone coating material.

[0060] Example 5:

[0061] A room-temperature curable solvent-free silicone coating material, the raw materials of which include an organosilicon prepolymer and a curing agent. The surface drying time of the room-temperature curable solvent-free silicone coating material is 15 min, the thickness is 10 μm, and the adhesion is grade 1;

[0062] A method for applying the above room-temperature curable solvent-free silicone coating material, comprising the following steps:

[0063] Step 1: Inject lower alcohol (methanol) with a molar ratio of 2:1:10 -4 :2, silane compound (the mass ratio of methyltrimethoxysilane and vinyltrimethoxysilane is 5:1), acid (sulfuric acid) and water (deionized water) into a reaction flask, mix well and react to obtain a silanol prepolymer. The reaction conditions include: temperature 60°C, time 3 h;

[0064] Step 2: Inject calcium carbonate (with a molar ratio of 2.5:1 to the acid) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 60°C, time 1.5 h;

[0065] Step 3: Subject the deacidified silanol prepolymer to solvent removal treatment to produce organosilicon prepolymer A (viscosity of 70 cst). The solvent removal treatment conditions include: vacuum pumping (vacuum degree of -0.05 MPa), temperature of 60 °C, and time of 2 h;

[0066] Step 4: Mix curing agent C (isopropyl titanate) and organosilicon prepolymer A with a mass ratio of 0.022:1, and then coat the mixture on the surface of the substrate and cure it at room temperature to produce a room-temperature-curing solvent-free organosilicon coating material.

[0067] Example 6:

[0068] A room-temperature-curing solvent-free organosilicon coating material, the raw materials of which include an organosilicon prepolymer and a curing agent. The surface drying time of the room-temperature-curing solvent-free organosilicon coating material is 15 min, the thickness is 12 μm, and the adhesion is grade 0;

[0069] An application method of the above room-temperature-curing solvent-free organosilicon coating material, which includes the following steps:

[0070] Step 1: Inject a lower alcohol (ethanol), a silane compound (the mass ratio of methyltriethoxysilane to vinyltriethoxysilane is 6:1), an acid (hydrochloric acid), and water (deionized water) with a molar ratio of 2.5:1:10 -4 :1 into a reaction flask, mix them evenly, and then react to obtain a silanol prepolymer. The reaction conditions include: temperature of 78 °C and time of 4 h;

[0071] Step 2: Inject calcium carbonate (the molar ratio to the acid is 2.5:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature of 78 °C and time of 1 h;

[0072] Step 3: Subject the deacidified silanol prepolymer to solvent removal treatment to produce organosilicon prepolymer A (viscosity of 40 cst). The solvent removal treatment conditions include: vacuum pumping (vacuum degree of -0.05 MPa), temperature of 78 °C, and time of 2.5 h;

[0073] Step 4: Mix curing agent C (organic titanium chelate), polysiloxane B (methyl MQ silicone resin), and organosilicon prepolymer A with a mass ratio of 0.02:0.02:1, and then coat the mixture on the surface of the substrate and cure it at room temperature to produce a room-temperature-curing solvent-free organosilicon coating material.

[0074] Example 7:

[0075] A room-temperature-curing solvent-free organosilicon coating material, the raw materials of which include an organosilicon prepolymer, a curing agent, and a linear polysiloxane. The surface drying time of the room-temperature-curing solvent-free organosilicon coating material is 35 min, the thickness is 15 μm, and the adhesion is grade 1;

[0076] A method for applying the above room-temperature curing solvent-free silicone coating material, comprising the following steps:

[0077] Step 1: Inject lower alcohols (methanol) with a molar ratio of 2:1:10 -4 :2, silane compounds (the mass ratio of methyltrimethoxysilane to octyltriethoxysilane is 10:1), acid (hydrochloric acid), and water (deionized water) into a reaction flask, mix well and react to obtain a silanol prepolymer. The reaction conditions include: temperature 50°C, time 3 h;

[0078] Step 2: Inject calcium carbonate (with a molar ratio to acid of 2.5:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 50°C, time 1.5 h;

[0079] Step 3: Perform a desolvation treatment on the deacidified silanol prepolymer to make silicone prepolymer A (viscosity 50 cst). The desolvation treatment conditions include: vacuum pumping (vacuum degree -0.05 MPa), temperature 50°C, time 1 h;

[0080] Step 4: Mix a curing agent C (dibutyltin diacetate), linear polysiloxane B (hydroxyl silicone oil), and silicone prepolymer A with a mass ratio of 0.025:0.1:1, coat the mixture on the surface of the substrate, and cure at room temperature to make a room-temperature curing solvent-free silicone coating material.

[0081] Example 8:

[0082] A room-temperature curing solvent-free silicone coating material, the raw materials of which include a silicone prepolymer, a curing agent, and a pigment filler. The surface drying time of the room-temperature curing solvent-free silicone coating material is 25 min, the thickness is 20 μm, and the adhesion is grade 1;

[0083] A method for applying the above room-temperature curing solvent-free silicone coating material, comprising the following steps:

[0084] Step 1: Inject lower alcohols (methanol) with a molar ratio of 2.5:1:10 -4 :2.5, silane compounds (the mass ratio of propyltrimethoxysilane to dodecyltrimethoxysilane is 20:1), acid (trifluoromethanesulfonic acid), and water (deionized water) into a reaction flask, mix well and react to obtain a silanol prepolymer. The reaction conditions include: temperature 60°C, time 4 h;

[0085] Step 2: Inject sodium bicarbonate (with a molar ratio to acid of 3:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 60°C, time 0.5 h;

[0086] Step 3: Subject the deacidified silanol prepolymer to desolvation treatment to obtain organosilicon prepolymer A (viscosity: 20 cst). The desolvation treatment conditions include: evacuating (vacuum degree: -0.05 MPa), temperature 60 °C, time 1.5 h;

[0087] Step 4: Mix a curing agent C (tetrabutyl titanate), a pigment and filler D (titanium dioxide, particle size 20 μm), and organosilicon prepolymer A with a mass ratio of 0.025:0.6:1, and then coat the mixture on the surface of the substrate and cure it at room temperature to obtain a room-temperature-curing solvent-free organosilicon coating material.

[0088] Example 9:

[0089] A room-temperature-curing solvent-free organosilicon coating material, the raw materials of which include an organosilicon prepolymer, a curing agent, and a pigment and filler. The surface drying time of the room-temperature-curing solvent-free organosilicon coating material is 45 min, the thickness is 12 μm, and the adhesion is grade 0;

[0090] An application method of the above room-temperature-curing solvent-free organosilicon coating material, comprising the following steps:

[0091] Step 1: Inject a lower alcohol (methanol), a silane compound (mass ratio of methyltrimethoxysilane to hexamethylcyclotrisiloxane is 15:1), an acid (trifluoromethanesulfonic acid), and water (deionized water) with a molar ratio of 3:1:10 -4 :1.5 into a reaction flask, mix them evenly, and then react to obtain a silanol prepolymer. The reaction conditions include: temperature 65 °C, time 3 h;

[0092] Step 2: Inject calcium carbonate (molar ratio to the acid is 3:1) into the silanol prepolymer obtained in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 65 °C, time 0.5 h;

[0093] Step 3: Subject the deacidified silanol prepolymer to desolvation treatment to obtain organosilicon prepolymer A (viscosity: 45 cst). The desolvation treatment conditions include: evacuating (vacuum degree: -0.05 MPa), temperature 65 °C, time 1.5 h;

[0094] Step 4: Mix a curing agent C (tetrabutyl titanate), a polysiloxane B (methoxy silicone oil), a pigment and filler D (iron oxide red, particle size 10 μm), and organosilicon prepolymer A with a mass ratio of 0.025:0.05:0.2:1, and then coat the mixture on the surface of the substrate and cure it at room temperature to obtain a room-temperature-curing solvent-free organosilicon coating material.

[0095] Example 10:

[0096] A room-temperature curing solvent-free silicone coating material, the raw materials of which include a silicone prepolymer, a curing agent, and a pigment and filler. The surface drying time of the room-temperature curing solvent-free silicone coating material is 25 min, the thickness is 18 μm, and the adhesion is grade 1;

[0097] An application method of the above-mentioned room-temperature curing solvent-free silicone coating material, comprising the following steps:

[0098] Step 1: Inject a lower alcohol (methanol) with a molar ratio of 2:1:10 -3 : 1.8, a silane compound (the mass ratio of methyltrimethoxysilane, octamethylcyclotetrasiloxane, and tridecafluorooctyltrimethoxysilane is 10:1:0.1), an acid (sulfuric acid), and water (deionized water) into a reaction flask, mix them evenly and then react to obtain a silanol prepolymer. The reaction conditions include: temperature 57 °C, time 3.5 h;

[0099] Step 2: Inject calcium carbonate (with a molar ratio to the acid of 5:1) into the silanol prepolymer in Step 1, stir and react, and then filter to obtain a deacidified silanol prepolymer. The reaction conditions include: temperature 57 °C, time 0.5 h;

[0100] Step 3: Perform a desolvation treatment on the deacidified silanol prepolymer to make a silicone prepolymer A (viscosity 45 cst). The desolvation treatment conditions include: evacuating (vacuum degree -0.05 MPa), temperature 57 °C, time 1.5 h;

[0101] Step 4: Mix a curing agent C (dialkyltin dimaleate), a pigment and filler D (cobalt blue, particle size 15 μm), and the silicone prepolymer A with a mass ratio of 0.025:0.2:1, and then coat them on the surface of the substrate and cure at room temperature to make a room-temperature curing solvent-free silicone coating material.

[0102] Comparative Example 1:

[0103] The difference between this comparative example and Example 9 is that the molar ratio of water to the silane compound is 5:1.

[0104] Comparative Example 2:

[0105] The difference between this comparative example and Example 9 is that the molar ratio of water to the silane compound is 0.6:1, and the rest is the same as in Example 9.

[0106] Comparative Example 3:

[0107] The difference between this comparative example and Example 9 is that the molar ratio of the lower alcohol (methanol) to the silane compound (the mass ratio of methyltrimethoxysilane to hexamethylcyclotrisiloxane is 15:1) is 0.4:1, and the rest is the same as in Example 9.

[0108] Comparative Example 4:

[0109] The difference between this comparative example and Example 9 is that the molar ratio of the lower alcohol (methanol) to the silane compound (the mass ratio of methyltrimethoxysilane to hexamethylcyclotrisiloxane is 15:1) is 6:1, and the rest is the same as in Example 9.

[0110] Comparative Example 5:

[0111] The difference between this comparative example and Example 9 is that the molar ratio of the calcium carbonate to the acid is 0:1, and the others are the same as in Example 9.

[0112] Comparative Example 6:

[0113] The difference between this comparative example and Example 9 is that the mass ratio of polysiloxane B (methoxy silicone oil) to organosilicon prepolymer A is 0.15:1, and the rest is the same as in Example 9.

[0114] Comparative Example 7:

[0115] The difference between this comparative example and Example 9 is that the mass ratio of curing agent C (tetrabutyl titanate) to the organosilicon prepolymer is 0.06:1, and the rest is the same as in Example 9.

[0116] Comparative Example 8:

[0117] The difference between this comparative example and Example 9 is that the mass ratio of curing agent C (tetrabutyl titanate) to organosilicon prepolymer A is 0.006:1, and the rest is the same as in Example 9.

[0118] Comparative Example 9:

[0119] The difference between this comparative example and Example 9 is that the mass ratio of pigment filler D (iron oxide red, particle size 10 μm) to organosilicon prepolymer A is 0.7:1, and the rest is the same as in Example 9.

[0120] Table 1 Application properties of room-temperature curing solvent-free organosilicon coating materials of Examples 1-10 and Comparative Examples 1-9

[0121] Surface drying time Thickness (μm) Adhesion Smoothness Appearance Example 1 50 min 15 Grade 2 Smooth The film layer is transparent Example 2 60 min 20 Grade 1 Smooth The film layer is transparent Example 3 50 min 15 Grade 2 Smooth The film layer is transparent Example 4 40 min 10 Grade 1 Smooth The film layer is transparent Example 5 15 min 10 Grade 1 Smooth The film layer is transparent Example 6 15 min 12 Grade 0 Smooth The film layer is transparent Example 7 35 min 15 Grade 1 Smooth The film layer is transparent Example 8 25 min 20 Grade 1 Smooth White film layer Example 9 45 min 12 Grade 0 Smooth Red film layer Example 10 25 min 18 Grade 1 Smooth Blue film layer Comparative Example 1 / / / Unable to form a smooth film layer / Comparative Example 2 48h 5 No adhesion / / Comparative Example 3 48h 5 No adhesion / / Comparative Example 4 / / / Unable to form a smooth film layer / Comparative Example 5 24h 5 No adhesion Smooth Red film layer Comparative Example 6 120 min 12 Grade 3 Smooth Red film layer Comparative Example 7 35 min 12 Grade 3 Smooth Red film layer Comparative Example 8 180 min 12 Grade 3 Smooth Red film layer Comparative Example 9 60 min 15 Grade 3 Smooth Red film layer

[0122] As shown in Table 1, the application performance of the room-temperature curing solvent-free silicone coating materials in Examples 1 to 10 meets the usage requirements of the composite coating materials (time ≤ 60 min, thickness ≤ 20 μm, adhesion ≤ Grade 2); in addition, from the data results of Comparative Examples 1 to 6, it can be obtained that the ratios of water to silane compounds, lower alcohols to silane compounds, and calcium carbonate to acid in the process of preparing the silicone prepolymer have an important impact on the viscosity of the finally prepared silicone prepolymer. When the ratios are not within the range defined in this application, problems such as excessive or too low viscosity of the silicone prepolymer will occur. If the viscosity is too high, a smooth film layer will be formed; if the viscosity is too low, the formed material will have no adhesion and cannot form a film layer structure on the material surface; in addition, the results of Comparative Examples 7, 8, and 9 show that if the ratio of the curing agent to the silicone prepolymer is too large, problems such as excessive adhesion and a yellowish film layer will occur, and if the ratio of the curing agent to the silicone prepolymer is too small, the problem of excessive adhesion will occur. Also, too large a particle size of the pigment filler will also cause the problem of excessive adhesion.

[0123] The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A room-temperature curing solvent-free silicone coating material, characterized in that, The raw materials include organosilicon prepolymer A, polysiloxane B, curing agent C and pigment filler D. The viscosity of the organosilicon prepolymer A is 5-100 cst. The organosilicon prepolymer A is prepared by reacting lower alcohols, silane compounds, acids and water, followed by deacidification and desolventization. Carbonate is used for deacidification, and evaporation and vacuum pumping are used for desolventization. The molar ratio of water to silane compound is 1-4:1, and the molar ratio of acid to silane compound is 10 -5 ~10 -3 :

1. The molar ratio of lower alcohol to silane compound is 0.5-5:

1.

2. The room-temperature curing solvent-free silicone coating material according to claim 1, characterized in that, the surface drying time of the room-temperature curing solvent-free silicone coating material is ≤ 60 min, the thickness is ≤ 20 μm, and the adhesion is ≤ grade 2.

3. The room-temperature curing solvent-free silicone coating material according to claim 1, characterized in that, the polysiloxane B includes one or more of silicone oil, silicone resin and modified silicone materials, and the mass ratio of the polysiloxane B to the silicone prepolymer A is 0~0.1:

1.

4. The room-temperature curing solvent-free silicone coating material according to claim 1, characterized in that, the pigment filler D includes one or several of titanium dioxide, iron oxide red, carbon black and cobalt blue, the particle size of the pigment filler D is ≤ 20 μm, and the mass ratio of the pigment filler D to the silicone prepolymer A is 0~0.6:

1.

5. The room-temperature curing solvent-free silicone coating material according to claim 1, characterized in that, the curing agent C includes one or several of organic titaniums, organic tins and organic bases, and the mass ratio of the curing agent C to the silicone prepolymer A is 0.01~0.05:

1.

6. An application method of the room-temperature curing solvent-free silicone coating material according to any one of claims 1~5, characterized in that, it includes the following preparation steps: Step 1: Mix a lower alcohol, a silane compound, an acid and water and react to obtain a silanol prepolymer; Step 2: Add a carbonate to the product of Step 1, react with the acid and then filter to obtain a deacidified silanol prepolymer; Step 3: Perform a desolvation treatment on the deacidified silanol prepolymer in Step 2 to make a silicone prepolymer A; Step 4: Mix the curing agent C, the polysiloxane B, the pigment filler D and the silicone prepolymer A in Step 3, coat them on the surface of the substrate and cure at room temperature to make a room-temperature curing solvent-free silicone coating material.

7. The method according to claim 6, characterized in that, the reaction conditions in Step 1 include: temperature 50~80°C, time 1~5 h.

8. The method according to claim 6, characterized in that, the reaction conditions in Step 2 include: stirring, temperature 50~80°C, time 0.5~2 h.

9. The method according to claim 6, characterized in that, the desolvation treatment conditions in Step 3 include: vacuum pumping, the vacuum degree is less than -0.05 MPa, the vacuum pumping time is 0.5~3 h, and the vacuum pumping temperature is 50~80°C.

10. The method according to claim 6, characterized in that, the lower alcohol includes one or several of methanol, ethanol and isopropanol; The silane compounds include one or more of methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, phenyltriethoxysilane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, 3,3,3-trifluoropropylmethylcyclotrisiloxane; The acid includes one of hydrochloric acid, sulfuric acid, acetic acid, trifluoromethanesulfonic acid; The water is deionized water; The carbonate includes one or more of sodium bicarbonate, sodium carbonate and calcium carbonate.