阅读说明：本技术 一种建筑物用复合纳米防水隔热涂料及其制备方法 (Composite nano waterproof heat-insulating coating for buildings and preparation method thereof ) 是由 李桂丽 于 2020-12-15 设计创作，主要内容包括：本发发明公开一种建筑物用复合纳米防水隔热涂料及其制备方法,属于涂料技术领域。本发明涂料包括以下重量份的原料：乳液150-200份、水性聚氨酯60-80份、填料60-80份、隔热复合纳米材料60-80份、有机硅疏水剂30-50份、成膜助剂5-10份、消泡剂3-6份、增效剂3-6份。本发明加入大量的隔热复合纳米材料,经过酸蚀和疏水两步改性,大大改善了材料的疏水隔热性能,同时添加的增效剂,其具备很强的粘附能力,可牢牢的吸附在纳米材料以及填料颗粒表面,使其在涂料中稳定的分散,大大减少后续涂料的起皮和开裂现象,延长涂料的使用寿命。本发明涂料隔热效果好,防水性能佳,使用寿命长,具有广阔的市场应用潜力。(The invention discloses a composite nano waterproof heat-insulating coating for buildings and a preparation method thereof, belonging to the technical field of coatings. The coating comprises the following raw materials in parts by weight: 200 parts of emulsion 150, 60-80 parts of waterborne polyurethane, 60-80 parts of filler, 60-80 parts of heat-insulating composite nano material, 30-50 parts of organic silicon hydrophobic agent, 5-10 parts of film-forming assistant, 3-6 parts of defoaming agent and 3-6 parts of synergist. According to the invention, a large amount of heat-insulating composite nano material is added, and the acid etching and hydrophobic modification are carried out, so that the hydrophobic heat-insulating property of the material is greatly improved, and meanwhile, the added synergist has strong adhesion capability, can be firmly adsorbed on the surfaces of the nano material and filler particles, so that the nano material and the filler particles are stably dispersed in the coating, the peeling and cracking phenomena of the subsequent coating are greatly reduced, and the service life of the coating is prolonged. The coating disclosed by the invention is good in heat insulation effect, good in waterproof performance, long in service life and wide in market application potential.)

1. The composite nano waterproof heat insulation coating for the building is characterized by comprising the following raw materials in parts by weight: 200 parts of emulsion 150, 60-80 parts of waterborne polyurethane, 60-80 parts of filler, 60-80 parts of heat-insulating composite nano material, 30-50 parts of organic silicon hydrophobic agent, 5-10 parts of film-forming assistant, 3-6 parts of defoaming agent and 3-6 parts of synergist.

2. The composite nano waterproof and heat insulation coating for the building as claimed in claim 1, wherein the heat insulation composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2-3 times, then soaking in a methyl triethoxysilane solution with the concentration of 50% for 6-12 hours, then placing in a muffle furnace to calcine at 450 ℃ for 3-5 hours, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

3. The composite nanometer waterproof and heat-insulating coating for the building as claimed in claim 1, wherein the filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to a mass ratio of 1:1: 5.

4. The composite nano waterproof heat insulation coating for the building as claimed in claim 1, wherein the film forming auxiliary agent is ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

5. The composite nano waterproof and heat insulating coating for buildings according to claim 1, wherein the defoaming agent is a silicone defoaming agent.

6. The composite nano waterproof and heat insulation coating for the building as claimed in claim 1, wherein the synergist is prepared by the following method: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80-90 deg.C for dissolving, cooling to 28-32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30-50min to obtain synergist.

7. The composite nano waterproof and heat insulating coating for buildings according to claim 6, wherein the weight ratio of the polyglutamic acid, the hyaluronic acid, the chitosan oligosaccharide and the water is 1-3:1-3:0.5-1:100, and the weight ratio of the N-N-hydroxysuccinimide to the water is 4-5: 100.

8. A preparation method of the composite nano waterproof and heat insulation coating for the building as claimed in any one of claims 1 to 7 is characterized by comprising the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2-3 times, then soaking in a methyl triethoxysilane solution with the concentration of 50% for 6-12 hours, then placing in a muffle furnace to calcine at 450 ℃ for 3-5 hours, and cooling to room temperature to obtain a heat-insulating composite nanomaterial;

(2) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80-90 deg.C for dissolving, cooling to 28-32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30-50min to obtain synergist;

(3) adding the emulsion into a stirring dispersion machine according to the weight part, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the weight part, and stirring for 30-40min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding a film-forming assistant and a defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the coating.

Technical Field

The invention belongs to the technical field of coatings, and particularly relates to a composite nano hydrophobic heat-insulating coating for buildings and a preparation method thereof.

Background

Waterproof coatings are one of the important components of building functional materials. In building construction, the waterproof coating mainly forms a waterproof layer on the surface of a building so as to achieve the purposes of waterproofing and leakage resistance, and therefore, the performance and the selection of the waterproof coating are directly related to the using effect and the service life of the building. At present, the waterproof coating on the market is mainly a polyurethane waterproof coating, an acrylic waterproof coating and other products. The polyurethane waterproof coating has excellent mechanical property and good waterproof property, but has poor weather resistance, is easy to foam in construction in high-temperature and high-humidity environments, has high requirement on the drying degree of a base material, and may contain free isocyanate harmful to human bodies; the acrylic waterproof paint has good weather resistance and environmental protection, but the water resistance of the paint film is poor, and the construction is difficult under the conditions of low temperature and high humidity.

With the consumption of available energy, energy-saving materials attract a great deal of attention from human beings. The heat insulation coating is a novel energy-saving material developed in recent years, and can effectively reflect the energy of sunlight and reduce the absorption of the surface of an object to the solar radiation energy, thereby achieving the effects of heat insulation and heat preservation. The heat insulation coating is used as a functional coating, and can reduce the surface temperature of an object, prevent heat conduction, improve the working environment and improve the safety. With the intensive research, the method also plays a certain role in the aspect of photocatalytic degradation of formaldehyde.

The quality of life of people is continuously improved, and the requirement on environmental protection is higher and higher, so that the market needs high-performance heat-insulating waterproof coatings with low odor, environmental protection and multiple functions.

Disclosure of Invention

In order to solve the problems of single coating function and poor environmental protection property in the market at present, the invention provides a novel waterproof heat-insulating coating for buildings, which has the advantages of good heat-insulating effect, good waterproof property, long service life, economy, safety and environmental protection and wide market application potential.

The technical scheme adopted by the invention is as follows:

a composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 200 parts of emulsion 150, 60-80 parts of waterborne polyurethane, 60-80 parts of filler, 60-80 parts of heat-insulating composite nano material, 30-50 parts of organic silicon hydrophobic agent, 5-10 parts of film-forming assistant, 3-6 parts of defoaming agent and 3-6 parts of synergist.

The emulsion used in the invention is polyacrylate emulsion, and the solid content is 50-60%.

The heat-insulating composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2-3 times, then soaking in a methyl triethoxysilane solution with the concentration of 50% for 6-12 hours, then placing in a muffle furnace to calcine at 450 ℃ for 3-5 hours, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

The synergist is prepared by the following steps: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80-90 deg.C for dissolving, cooling to 28-32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30-50min to obtain synergist.

The weight ratio of the polyglutamic acid to the hyaluronic acid to the chitosan oligosaccharide to the water is 1-3:1-3:0.5-1: 100.

The weight ratio of the N-N-hydroxysuccinimide to the water is 4-5: 100.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2-3 times, then soaking in a methyl triethoxysilane solution with the concentration of 50% for 6-12 hours, then placing in a muffle furnace to calcine at 450 ℃ for 3-5 hours, and cooling to room temperature to obtain a heat-insulating composite nanomaterial;

(2) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80-90 deg.C for dissolving, cooling to 28-32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30-50min to obtain synergist;

(3) adding the emulsion into a stirring dispersion machine according to the weight part, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the weight part, and stirring for 30-40min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding a film-forming assistant and a defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the coating.

The nano titanium dioxide and nano silicon dioxide powder used in the invention are obtained commercially, and the preferred particle size is 30-100 nm.

The components of the coating composition can produce synergistic effect while playing a role respectively, so that the heat insulation and waterproof effects of the coating are optimal. According to the invention, a large amount of heat-insulating composite nano material is added, the hydrophobic property of the material is greatly improved through two-step modification of acid etching and hydrophobic property, and the integral waterproof property of the coating is further enhanced by matching with the added hydrophobic agent. The filler such as diatomite with low heat conductivity coefficient is added, the light and porous performance of the filler can enhance the adhesive force of the coating, and the heat insulation performance of the coating is further enhanced by matching with the talcum powder and the light calcium carbonate. Meanwhile, the diatomite and the like can adsorb the gas emitted by the coating, so that the emission of the smell of the coating is greatly reduced. The synergist added in the invention is a gel substance, has strong adhesive capacity, can be firmly adsorbed on the surfaces of the nano material and the filler particles, enables the nano material and the filler particles to be stably dispersed in the coating, can assist the inorganic particles to be tightly attached to the surface of a building, greatly reduces the peeling and cracking phenomena of the subsequent coating, and prolongs the service life of the coating. The coating disclosed by the invention is good in heat insulation effect, good in waterproof performance, long in service life, economic, safe and environment-friendly, and has wide market application potential.

Detailed Description

The technical solution of the present invention is further described below with reference to specific embodiments, but is not limited thereto.

Example 1

A composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 150 parts of emulsion, 60 parts of waterborne polyurethane, 60 parts of filler, 60 parts of heat-insulating composite nano material, 30 parts of organic silicon hydrophobic agent, 5 parts of film-forming assistant, 3 parts of defoaming agent and 3 parts of synergist.

The emulsion used in this example was a polyacrylate emulsion with a solids content of 50%.

The heat-insulating composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 6 hours, then placing in a muffle furnace, calcining at 450 ℃ for 3 hours, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

The synergist is prepared by the following steps: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80 deg.C for dissolving, cooling to 28 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30min to obtain synergist.

The weight ratio of the polyglutamic acid to the hyaluronic acid to the chitosan oligosaccharide to the water is 1:1:0.5: 100.

The weight ratio of the N-N-hydroxysuccinimide to the water is 4: 100.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 2 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 6-12 hours, then placing in a muffle furnace, calcining for 3 hours at 450 ℃, and cooling to room temperature to obtain a heat-insulating composite nano material;

(2) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 80-90 deg.C for dissolving, cooling to 28-32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 30-50min to obtain synergist;

(3) adding the emulsion into a stirring dispersion machine according to the parts by weight, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the parts by weight, and stirring for 30min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding a film-forming aid and a defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the coating of the embodiment.

Example 2

A composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 180 parts of emulsion, 70 parts of waterborne polyurethane, 70 parts of filler, 70 parts of heat-insulating composite nano material, 40 parts of organic silicon hydrophobic agent, 8 parts of film-forming assistant, 5 parts of defoaming agent and 4 parts of synergist.

The emulsion used in this example was a polyacrylate emulsion with a solids content of 55%.

The heat-insulating composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 10 hours, then placing in a muffle furnace, calcining for 4 hours at 450 ℃, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

The synergist is prepared by the following steps: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 85 deg.C for dissolving, cooling to 30 deg.C, adding N-N-hydroxysuccinimide, and crosslinking for 40min to obtain synergist.

The weight ratio of the polyglutamic acid to the hyaluronic acid to the chitosan oligosaccharide to the water is 2:2:0.8: 100.

The weight ratio of the N-N-hydroxysuccinimide to the water is 4.5: 100.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyl triethoxysilane solution with the concentration of 50% for 10 hours, then placing in a muffle furnace, calcining for 4 hours at 450 ℃, and cooling to room temperature to obtain a heat-insulating composite nano material;

(2) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 85 deg.C for dissolving, cooling to 30 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 40min to obtain synergist;

(3) adding the emulsion into a stirring dispersion machine according to the parts by weight, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the parts by weight, and stirring for 35min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding a film-forming aid and a defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the coating of the embodiment.

Example 3

A composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 200 parts of emulsion, 80 parts of waterborne polyurethane, 80 parts of filler, 80 parts of heat-insulating composite nano material, 50 parts of organic silicon hydrophobic agent, 10 parts of film-forming assistant, 6 parts of defoaming agent and 6 parts of synergist.

The emulsion used in this example was a polyacrylate emulsion with a solids content of 60%.

The heat-insulating composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 12 hours, then placing in a muffle furnace, calcining for 5 hours at 450 ℃, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

The synergist is prepared by the following steps: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 90 deg.C for dissolving, cooling to 32 deg.C, adding N-N-hydroxysuccinimide, and crosslinking for 50min to obtain synergist.

The weight ratio of the polyglutamic acid to the hyaluronic acid to the chitosan oligosaccharide to the water is 3:3:1: 100.

The weight ratio of the N-N-hydroxysuccinimide to the water is 5: 100.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 12 hours, then placing in a muffle furnace, calcining at 450 ℃ for 5 hours, and cooling to room temperature to obtain a heat-insulating composite nano material;

(2) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 90 deg.C for dissolving, cooling to 32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 50min to obtain synergist;

(3) adding the emulsion into a stirring dispersion machine according to the parts by weight, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the parts by weight, and stirring for 40min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding a film-forming aid and a defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the coating of the embodiment.

Comparative example 1

A composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 200 parts of emulsion, 80 parts of waterborne polyurethane, 80 parts of filler, 80 parts of nano material, 50 parts of organic silicon hydrophobic agent, 10 parts of film-forming assistant, 6 parts of defoaming agent and 6 parts of synergist.

The emulsion used in this comparative example was a polyacrylate emulsion with a solids content of 60%.

The nano material is obtained by mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1: 1.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

The synergist is prepared by the following steps: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 90 deg.C for dissolving, cooling to 32 deg.C, adding N-N-hydroxysuccinimide, and crosslinking for 50min to obtain synergist.

The weight ratio of the polyglutamic acid to the hyaluronic acid to the chitosan oligosaccharide to the water is 3:3:1: 100.

The weight ratio of the N-N-hydroxysuccinimide to the water is 5: 100.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a synergist: adding polyglutamic acid, hyaluronic acid and chitosan oligosaccharide into water, heating to 90 deg.C for dissolving, cooling to 32 deg.C, adding N-N-hydroxysuccinimide for crosslinking for 50min to obtain synergist;

(2) adding the emulsion into a stirring dispersion machine according to the parts by weight, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material, the organic silicon hydrophobic agent and the synergist according to the parts by weight, and stirring for 40min to uniformly disperse the mixture;

(3) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding the film-forming assistant and the defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the comparative paint.

The formulation and preparation method of this comparative example are the same as those of example 3, except that the common nano-silica and titanium dioxide powders are used.

Comparative example 2

A composite nano waterproof heat insulation coating for buildings comprises the following raw materials in parts by weight: 200 parts of emulsion, 80 parts of waterborne polyurethane, 80 parts of filler, 80 parts of heat-insulating composite nano material, 50 parts of organic silicon hydrophobic agent, 10 parts of film-forming assistant and 6 parts of defoaming agent.

The emulsion used in this comparative example was a polyacrylate emulsion with a solids content of 60%.

The heat-insulating composite nano material is prepared by the following method: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 12 hours, then placing in a muffle furnace, calcining for 5 hours at 450 ℃, and cooling to room temperature to obtain the heat-insulating composite nanomaterial.

The filler is prepared by mixing talcum powder, light calcium carbonate and diatomite according to the mass ratio of 1:1: 5.

The film-forming assistant is prepared from ethylene glycol and turpentine according to a mass ratio of 1: 3, and mixing the two components.

The defoaming agent is an organic silicon defoaming agent, and the solid content is more than 99.9%.

A preparation method of a composite nano waterproof heat insulation coating for buildings comprises the following steps:

(1) preparing a heat-insulating composite nano material: uniformly mixing nano silicon dioxide powder and nano titanium dioxide powder according to the mass ratio of 1:1, completely soaking in a nitric acid solution with the mass percentage of 50% for 24 hours, then washing with deionized water for 3 times, soaking in a methyltriethoxysilane solution with the concentration of 50% for 12 hours, then placing in a muffle furnace, calcining at 450 ℃ for 5 hours, and cooling to room temperature to obtain a heat-insulating composite nano material;

(3) adding the emulsion into a stirring dispersion machine according to the parts by weight, wherein the rotating speed is 200r/min, then sequentially adding the filler, the heat-insulating composite nano material and the organic silicon hydrophobic agent according to the parts by weight, and stirring for 40min to uniformly disperse the mixture;

(4) and increasing the rotating speed to 500r/min, adding waterborne polyurethane in the stirring process, adding the film-forming assistant and the defoaming agent, stirring at a high speed, and standing for 12 hours to obtain the comparative paint.

The formulation and preparation method of this comparative example were the same as example 3 except that no synergist was added and prepared.

Test experiments

The coatings obtained in examples 1 to 3 and comparative examples 1 to 2 were tested, and a control example (i.e., a commercial ordinary heat-insulating waterproof coating) was set, and the covering power (GB/T1726-79), water resistance (GB/T9274-1988), adhesion (GB/T1720-79), drying time (GB/T1728-79), impact resistance (GB/T1732-93) and the like were tested, respectively, heat-insulating performance was measured according to the heat-insulating effect test described in JG/T235-2008 standard, hardness was measured according to the GB/T6739 standard, reflectance of the coating was measured using an ultraviolet-visible-infrared spectrophotometer lambda950, contact angle after spraying was measured using a contact angle tester, and specific test results are shown in Table 1 below:

table 1 results of performance testing

It should be noted that the above-mentioned embodiments are only some of the preferred modes for implementing the invention, and not all of them. Obviously, all other embodiments obtained by persons of ordinary skill in the art based on the above-mentioned embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.