High temperature resistant thermal barrier inorganic coating, method of making and use in fire fighting equipment

Abstract

The application discloses a high-temperature-resistant heat-insulating inorganic coating and a preparation method and application in fire-fighting equipment thereof, and belongs to the field of thermal protection coating. The high-temperature-resistant heat-insulating inorganic coating comprises a bonding inner layer and a high-temperature-resistant heat-insulating outer layer, the bonding inner layer is prepared from bonding inner layer coating material, raw materials of which comprise water-based silicone resin emulsion and water glass, and the high-temperature-resistant heat-insulating outer layer is prepared from high-temperature-resistant heat-insulating outer layer coating material, raw materials of which comprise water glass, hollow glass microbeads, mullite whiskers, titanium oxide whiskers, tellurium oxide powder and boron oxide powder. The high-temperature-resistant heat-insulating inorganic coating is combined by the bonding inner layer and the high-temperature-resistant heat-insulating outer layer, can not only improve the adhesion of the coating to the base body, but also improve the thermal stability of the whole coating, reduces the cracking of the coating, and has the advantages of simple preparation method, low raw material cost and easy availability; the high-temperature-resistant heat-insulating inorganic coating can be applied to fire-fighting equipment as a heat-resistant heat-insulating protective layer, and can greatly improve the high-temperature-resistant performance and service life of the fire-fighting equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of thermal protection coating, in particular to a high-temperature-resistant heat-insulating inorganic coating, a preparation method thereof and application thereof in fire-fighting equipment. BACKGROUND

[0002] The service environment of fire-fighting equipment, boiler of thermal power plant and other equipment is usually high-temperature environment, which often faces high-temperature corrosion and oxidation, and is easy to cause great reduction of service life of the equipment. Therefore, the existing equipment usually forms a coating on the surface of the equipment by organic coating or inorganic coating to protect the equipment.

[0003] The organic coating usually has the shortcomings of poor temperature resistance, high volatile organic compounds, etc. Compared with the organic coating, the inorganic coating usually has the advantages of high upper limit of temperature resistance, small environmental pollution in production process, etc., but also has the shortcomings of low adhesion to the substrate, easy cracking, relatively poor water resistance, etc.

[0004] The commonly used high-temperature-resistant inorganic coating mainly includes silicate high-temperature-resistant coating, phosphate high-temperature-resistant coating and silica sol high-temperature-resistant coating. Compared with the phosphate high-temperature-resistant coating which solidifies too fast due to metal oxides and the silica sol coating which cracks due to too high cohesion in the process of dehydration polymerization, the silicate high-temperature-resistant coating exhibits excellent air permeability, acid and alkali resistance, fire resistance, mildew resistance, antibacterial property and environmental protection. However, the existing silicate coating still has the problems of large rigidity and easy cracking.

[0005] Therefore, it is necessary to further optimize the existing inorganic coating to develop a silicate high-temperature-resistant coating which is low in cost, not easy to crack, simple to prepare and long in service life. SUMMARY

[0006] The present application aims to provide a high-temperature-resistant heat-insulating inorganic coating which is not easy to crack, good in water resistance, low in cost and simple to prepare, and a preparation method of the high-temperature-resistant heat-insulating inorganic coating and application thereof in fire-fighting equipment.

[0007] The high-temperature-resistant heat-insulating inorganic coating comprises a bonding inner layer and a high-temperature-resistant heat-insulating outer layer. The bonding inner layer is prepared from a bonding inner layer coating, and the raw material of the bonding inner layer coating comprises water-based silicone resin emulsion and water glass. The high-temperature-resistant heat-insulating outer layer is prepared from a high-temperature-resistant heat-insulating outer layer coating, and the raw material of the high-temperature-resistant heat-insulating outer layer coating comprises water glass, hollow glass microspheres, mullite whiskers, titanium oxide whiskers, tellurium oxide powder and boron oxide powder.

[0008] Further, in the bonding inner layer, the mass ratio of the water-based silicone resin emulsion to the water glass is 70-85:15-30, preferably 80:20.

[0009] Further, the mass ratio of the water glass, the hollow glass microsphere, the mullite whisker, the titanium oxide whisker, the tellurium oxide powder and the boron oxide powder in the high-temperature-resistant and heat-insulating outer layer is 35-55:20-30:10-15:5-10:2-10:1-3, preferably 45:30:12:6:5:2.

[0010] Further, the modulus of the water glass is 3.10-3.40, preferably 3.3; the diameter of the hollow glass microsphere is 20-100 microns, preferably 70 microns; the length of the mullite whisker is 10-50 microns and the diameter is 0.03-1 micron, preferably, the length is 30 microns and the diameter is 0.5 micron; the length of the titanium oxide whisker is 2-10 microns and the diameter is 0.02-1 micron, preferably, the length is 5 microns and the diameter is 0.5 micron; the particle size of the tellurium oxide powder is 1000-4000 mesh, preferably 3000 mesh; the particle size of the boron oxide powder is 1000-4000 mesh, preferably 3000 mesh.

[0011] Further, the water glass is one or more of sodium water glass, potassium water glass or lithium water glass, preferably, the water glass is composed of sodium water glass, potassium water glass and lithium water glass with a mass ratio of 1:1:2.

[0012] Further, the thickness ratio of the adhesive inner layer and the high-temperature-resistant and heat-insulating outer layer is 30-100 microns:0.5-1.5 mm.

[0013] Further, the water glass used in the adhesive inner layer and the water glass used in the high-temperature-resistant and heat-insulating outer layer are the same.

[0014] The preparation method of the above high-temperature-resistant and heat-insulating inorganic coating includes the following steps:

[0015] (1) preparing an adhesive inner layer coating;

[0016] (2) preparing a high-temperature-resistant and heat-insulating outer layer coating;

[0017] (3) first, the adhesive inner layer coating is sprayed on the outer surface of the substrate, dried to obtain a substrate with an adhesive inner layer; then, the high-temperature-resistant and heat-insulating outer layer coating is scraped or brushed on the outer surface of the adhesive inner layer, dried, and then solidified to obtain a substrate with a high-temperature-resistant and heat-insulating inorganic coating.

[0018] Further, in step (1), the preparation method of the adhesive inner layer coating is: mixing and stirring the water-based silicone resin emulsion and the water glass for 10-15 minutes, and then obtaining the adhesive inner layer coating after mixing.

[0019] Further, in step (2), the preparation method of the high-temperature-resistant heat-insulating outer coating is as follows: first, hollow glass microspheres, mullite whiskers, titanium oxide whiskers, tellurium oxide powder and boron oxide powder are mixed and stirred for 5-15 min, then sodium silicate is added and stirred for 10-15 min, and the mixture is uniformly mixed to obtain the heat-insulating outer coating.

[0020] Further, in step (3), the parameters of spraying are as follows: the spray gun caliber is 1.0-4.0 mm, the spraying distance is 15-30 cm, and the spraying time is 3-10 s; and the curing conditions are as follows: curing at 110-140 DEG C for 1.5-3 h.

[0021] The application provides application of the high-temperature-resistant heat-insulating inorganic coating as a heat-resistant heat-insulating protective layer in fire-fighting equipment.

[0022] The application principle is as follows: in the application, the adhesive inner layer coating mainly uses water-based silicone resin latex, has good adhesion and flexibility, a small amount of sodium silicate which is the same as that used in the heat-insulating outer coating is compounded to increase the matching of the adhesive inner layer and the heat-insulating outer coating, and then the heat-insulating outer coating is bonded to the adhesive inner layer with good flexibility, so that the overall coating is not easily damaged, and the overall service life of the coating is improved.

[0023] Further, the addition of titanium oxide whiskers in the heat-insulating outer coating can increase the toughness of the coating and reduce cracking of the coating in high-temperature application, and the addition of mullite whiskers can significantly reduce the cost of the coating while increasing the toughness and preventing cracking;

[0024] In addition, the melting point of tellurium oxide is 733 DEG C, and the melting point of boron oxide is 450 DEG C, so that a small amount of tellurium oxide and a small amount of boron oxide can fill the cracks on the surface of the coating in high-temperature application, and improve the high-temperature thermal stability and thermal shock resistance of the coating.

[0025] Advantages: compared with the prior art, the application has the following advantages:

[0026] (1) the high-temperature-resistant heat-insulating inorganic coating is combined by the adhesive inner layer and the high-temperature-resistant heat-insulating outer layer, which can not only improve the adhesion of the coating to the substrate, but also improve the thermal stability of the overall coating and reduce cracking of the coating;

[0027] (2) the preparation method is simple, the raw material cost is low, and the raw material is easy to obtain;

[0028] (3) the high-temperature-resistant heat-insulating inorganic coating is applied to fire-fighting equipment, which can provide heat-resistant heat-insulating protection for the near-fire service of the fire-fighting equipment. DETAILED DESCRIPTION

[0029] The application will be further described below in conjunction with specific embodiments.

[0030] The high-temperature-resistant and heat-insulating inorganic coating provided in this embodiment comprises a bonding inner layer and a high-temperature-resistant and heat-insulating outer layer,

[0031] The bonding inner layer is prepared from the bonding inner layer coating, and the raw materials include water-based silicone resin emulsion and water glass with a modulus of 3.3 at a mass ratio of 80:20, wherein the water glass is composed of sodium water glass, potassium water glass and lithium water glass at a mass ratio of 1:1:2.

[0032] The high-temperature-resistant and heat-insulating outer layer is prepared from the high-temperature-resistant and heat-insulating outer layer coating, and the raw materials include water glass with a modulus of 3.3, hollow glass microbeads with a diameter of 70 microns, mullite whiskers with a length of 30 microns and a diameter of 0.5 microns, titanium oxide whiskers with a length of 5 microns and a diameter of 0.5 microns, tellurium oxide powder with a particle size of 3000 mesh, and boron oxide powder with a particle size of 3000 mesh at a mass ratio of 45:30:12:6:5:2, wherein the water glass is composed of sodium water glass, potassium water glass and lithium water glass at a mass ratio of 1:1:2.

[0033] The thickness ratio of the bonding inner layer to the high-temperature-resistant and heat-insulating outer layer is 50 microns:1 millimeter.

[0034] The preparation method of the high-temperature-resistant and heat-insulating inorganic coating comprises the following steps:

[0035] (1) Preparing the bonding inner layer coating: mixing and stirring the water-based silicone resin emulsion and the water glass for 10-15 minutes to obtain the bonding inner layer coating.

[0036] (2) Preparing the high-temperature-resistant and heat-insulating outer layer coating: first mixing and stirring the hollow glass microbeads, the mullite whiskers, the titanium oxide whiskers, the tellurium oxide powder and the boron oxide powder for 5-15 minutes, then adding the water glass and continuing to stir for 10-15 minutes to obtain the high-temperature-resistant and heat-insulating outer layer coating.

[0037] (3) First, the bonding inner layer coating is filled into a gravity type coating pot and sprayed on the outer surface of the substrate, and the spraying parameters are as follows: the spraying gun caliber is 1.5 mm, the spraying distance is 20 cm, and the spraying time is 5 seconds. After drying in the room for 2-4 hours, the substrate with the bonding inner layer is obtained. Then, the high-temperature-resistant and heat-insulating outer layer coating is applied by scraping or brushing on the outer surface of the bonding inner layer, and after drying for at least 24 hours in a windless environment, the substrate with the high-temperature-resistant and heat-insulating inorganic coating is obtained after curing at 120℃ for 2 hours.

[0038] It can withstand 800℃ and can work at 750℃ for a long time. (The fire surface can withstand 800℃, and the backfire surface can be heat-insulated to 300℃)

[0039] Example 2: Other same as example 1, only change the weight ratio of silicone resin emulsion and water glass in the total amount of the inner layer adhesive coating, the higher water glass content (70:30) of the inner layer adhesive coating significantly reduces the adhesion and toughness after curing, and the coating shows easy cracking in macroscopic. While the higher content of silicone resin emulsion even without water glass component (90:10 and 100:0) shows strong adhesion with workpiece and equipment, but the compatibility with the outer layer of heat resistance is not good, the adhesion decreases at room temperature, not easy to move, and shows large piece of shedding failure at high temperature.

[0040] Example 3: Only change the total amount of mullite whisker and titanium oxide whisker in the outer layer of heat resistance coating, no addition, 25 (15:10). The outer layer of heat resistance coating without adding whisker material is easy to crack during use, and is difficult to use in actual application. The coating with 25 (15:10) of whisker shows poor heat insulation performance compared with example 1, the fire surface is 800℃, and the backfire surface is insulated to 350℃.

[0041] Comparative example 1: Other same as example 1, no tellurium oxide powder is added in the outer layer of heat resistance coating, which leads to the decrease of heat resistance of the coating, and easy cracking at high temperature, which is difficult to use above 600℃.

Claims

1. A high temperature resistant thermal insulating inorganic coating applied in fire fighting equipment as a heat resistant thermal barrier, characterized in that, The inorganic coating comprises a bonding inner layer and a high-temperature-resistant and heat-insulating outer layer, the bonding inner layer is prepared from a bonding inner layer coating material, raw materials of the bonding inner layer coating material comprise a water-based silicone resin emulsion and water glass in a mass ratio of 70-85:15-30, the high-temperature-resistant and heat-insulating outer layer is prepared from a high-temperature-resistant and heat-insulating outer layer coating material, raw materials of the high-temperature-resistant and heat-insulating outer layer coating material comprise water glass, hollow glass microbeads, mullite whiskers, titanium oxide whiskers, tellurium oxide powder and boron oxide powder in a mass ratio of 35-55:20-30:10-15:5-10:2-10:1-3, a thickness ratio of the bonding inner layer to the high-temperature-resistant and heat-insulating outer layer is 30-100 μm:0.5-1.5 mm, the water glass used in the bonding inner layer and the water glass used in the high-temperature-resistant and heat-insulating outer layer have the same composition, and the water glass is composed of sodium water glass, potassium water glass and lithium water glass in a mass ratio of 1:1:

2.

2. A method for preparing the high temperature resistant, thermally insulating inorganic coating according to claim 1, characterized in that, The method comprises the following steps: (1) preparing a bonding inner layer coating material; (2) preparing a high-temperature-resistant and heat-insulating outer layer coating material; (3) first spraying the bonding inner layer coating material on the outer surface of a substrate, drying to obtain a substrate with a bonding inner layer; then scraping or brushing the high-temperature-resistant and heat-insulating outer layer coating material on the outer surface of the bonding inner layer, drying, and then performing a curing treatment to obtain a substrate with a high-temperature-resistant and heat-insulating inorganic coating.

3. The method for preparing a high temperature resistant, thermally barrier inorganic coating according to claim 2, characterized in that, In step (3), the spraying parameters are as follows: a spray gun caliber of 1.0-4.0 mm, a spraying distance of 15-30 cm, and a spraying time of 3-10 s.

4. The method of claim 2, wherein the method further comprises the step of: In step (3), the curing conditions are as follows: curing at 110-140 ℃ for 1.5-3 h.