A high-temperature resistant, low-thermal-conductivity thermal insulation coating and its preparation method

Abstract

The present application discloses a high-temperature resistant, low-thermal conductivity thermal insulation coating and its preparation method. The thermal insulation coating includes the following raw materials by weight: 10-20 parts of inorganic silicate solution; 10-15 parts of organosilicon-modified phenolic resin; 30-50 parts of hollow ceramic microspheres; 10-20 parts of aluminum silicate fiber; 20-25 parts of thickener; 10-15 parts of water; 3-5 parts of nano-α-alumina; 3-4 parts of nano-rutile titanium dioxide; 1-2 parts of dispersant and 1-2 parts of flame retardant. The present application improves the softness of the thermal insulation resin by organosilicon-modified phenolic resin, thereby improving the toughness of the thermal insulation coating; after cross-linking by hydroxyl groups in organosilicon and polyol, it is also beneficial to improve the adhesion of the thermal insulation coating, avoiding the influence of organosilicon on the bonding performance of the thermal insulation coating.

Description

Technical Field

[0001] The present application relates to the technical field of coating compositions, and in particular to a heat-insulating coating with high temperature resistance and low thermal conductivity and a preparation method thereof. Background Art

[0002] CN107201067A discloses a high-temperature resistant heat-insulating coating and its preparation method. The components and their weight proportions are as follows: 10-20 parts of sodium-lithium silicate composite liquid; 5-20 parts of water-based phenolic resin; 30-50 parts of ceramic hollow microspheres; 10-30 parts of short ceramic fibers; 1-6 parts of bentonite; 1-8 parts of aluminum flake powder; 0.5-3 parts of preservative; 0.5-3 parts of stabilizer; 0.5-3 parts of water-based dispersant; 0.5-5 parts of coupling agent; 0.2-0.8 parts of carboxymethyl cellulose; and 0.1-3 parts of pH regulator. The high-temperature resistant heat-insulating coating is able to have good adhesion due to the phenolic resin. The excellent adhesion of the phenolic resin is due to the large number of polar groups in its macromolecular structure. The strong polarity is a favorable factor that promotes its wetting and adhesion to materials.

[0003] However, the polar groups in the molecular chain of phenolic resin will lead to a large intermolecular force, which affects the flexibility of the coating and is prone to brittle cracking, peeling and so on. Therefore, it is necessary to provide a high temperature resistant thermal insulation coating with good adhesion and flexibility. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a heat-insulating coating with high temperature resistance and low thermal conductivity, and the technical solution adopted is as follows:

[0005] The high temperature resistant, low thermal conductivity thermal insulation coating comprises the following raw materials in parts by weight:

[0006]

[0007] As a preferred embodiment: the preparation method of the organosilicon-modified phenolic resin is: in the presence of a catalyst, formaldehyde, a phenolic compound, organosilicon, and a polyol react to obtain the organosilicon-modified phenolic resin.

[0008] As a preferred embodiment: the organic silicone is polyether silicone oil.

[0009] As a preferred embodiment, the polyol is a polyether polyol having a relative molecular mass of 1000-2000 and a hydroxyl value of 350-500 mgKOH / g. This ensures the toughness of the silicone-modified phenolic resin while also ensuring the degree of crosslinking between the polyether polyol and the silicone, thereby improving the mechanical properties of the coating.

[0010] As a preferred embodiment: the phenolic compound is one or more of phenol, bisphenol A, and hydroquinone.

[0011] As a preferred embodiment: the inorganic silicate solution is a sodium lithium silicate composite solution.

[0012] The thermal conductivity of the sodium-lithium silicate composite liquid is very low, and lithium silicate acts as a solvent. After film formation, the coating becomes denser, which is conducive to film formation and thermal insulation, and also improves the anti-permeability and waterproof functions of the coating.

[0013] The present application also proposes a method for preparing a high-temperature resistant, low-thermal conductivity thermal insulation coating, comprising: mixing 10-20 parts by weight of an inorganic silicate solution, 10-15 parts by weight of an organosilicon-modified phenolic resin, and 20-25 parts by weight of water, rapidly stirring at high temperature for 0.5-1h until the mixture is stirred and matured, adding 20-25 parts by weight of a thickener and 1-2 parts by weight of a dispersant and continuing to stir for 0.5-1h, then adding 30-50 parts by weight of hollow ceramic microbeads and 10-20 parts by weight of aluminum silicate fibers and continuing to stir for 0.5-1h to obtain a thermal insulation coating.

[0014] The beneficial effects of the present invention are:

[0015] The coating film obtained after the application of the thermal insulation coating of the present application has excellent toughness, and also has wear resistance, high temperature resistance and aging resistance, and has a long service life;

[0016] This application improves the softness of the thermal insulation resin by modifying the phenolic resin with organic silicon, thereby improving the toughness of the thermal insulation coating and preventing the thermal insulation coating from cracking after construction and curing;

[0017] The organosilicon-modified phenolic resin is prepared by reacting formaldehyde and phenolic compounds in the presence of a catalyst, and simultaneously modifying the phenolic resin with organosilicon and polyol. The organosilicon and polyol are cross-linked through hydroxyl groups to form a three-dimensional network structure. The hollow ceramic microspheres mixed with the organosilicon-modified phenolic resin are tightly arranged in the three-dimensional network structure, and a three-dimensional air layer is also present between the hollow ceramic microspheres to form a static air layer, reducing heat convection. Silicates with a relatively low thermal conductivity serve as an inorganic film-forming substance to support the coating. The film-forming substance and the three-dimensional air layer together form a heat-insulating shielding layer, so that the thermal conductivity of the coating formed after the thermal insulation coating is applied is close to the thermal conductivity of a vacuum, thereby playing an effective role in heat insulation and heat preservation.

[0018] Moreover, due to the three-dimensional network structure formed in the thermal insulation coating, it is beneficial to improve the physical properties of the coating film formed after curing, and has excellent wear resistance, chemical resistance and water resistance;

[0019] Nano-α-alumina has excellent thermal and chemical stability, which is beneficial to improving the high temperature resistance of thermal insulation coatings;

[0020] Rutile titanium dioxide has a high refractive index and can reflect ultraviolet rays. At the same time, rutile titanium dioxide has good weather resistance, which improves the anti-aging ability of the coating.

[0021] After cross-linking through hydroxyl groups in silicone and polyols, it is also beneficial to improve the adhesion of thermal insulation coatings and avoid the influence of silicone on the bonding performance of thermal insulation coatings. DETAILED DESCRIPTION

[0022] This section describes specific embodiments of the present invention in detail.

[0023] In this embodiment, the preparation method of the organosilicon-modified phenolic resin is as follows: 2 g of catalyst, 15 g of formaldehyde, 30 g of phenolic compound, 8 g of organosilicon, and 2 g of polyol are prepared for reaction; after adding 2 g of catalyst to 30 g of phenolic compound, the temperature is raised to 45° C., 8 g of organosilicon and 2 g of polyol are added, and the reaction is carried out at 40-50° C. for 1 hour; then 15 g of formaldehyde is added and the reaction is continued at a temperature of 60-65° C. for 2 hours, and the reaction is refluxed at a temperature of 80-90° C. for 1 hour and the temperature is reduced to obtain the organosilicon-modified phenolic resin.

[0024] Among them, the catalyst is sodium hydroxide; the phenolic compound is one or more of phenol, bisphenol A, and hydroquinone, and phenol is used in this embodiment; the organosilicon is polyether silicone oil, and polyether silicone oil with CAS number 9016-00-6 is used in this embodiment; the polyol is polyether polyol, the relative molecular mass of the polyether polyol is 1000-2000, and the hydroxyl value is 350-500 mgKOH / g, and polyether triol is used in this embodiment.

[0025] After the above-mentioned organosilicon-modified phenolic resin is prepared, 10-20 parts by weight of an inorganic silicate solution, 10-15 parts by weight of an organosilicon-modified phenolic resin and 10-15 parts by weight of water are mixed, and the mixture is rapidly stirred at a high temperature for 0.5-1 hour until stirring and maturation. The stirring and maturation rotation speed needs to reach 3500 r / min or more. After adding 20-25 parts by weight of a thickener, 3-5 parts by weight of nano-α-alumina powder, 3-4 parts by weight of nano-rutile titanium dioxide, 1-2 parts by weight of a dispersant and 1-2 parts by weight of a flame retardant, stirring is continued at a speed of 200 r / min for 0.5-1 hour, and then 30-50 parts by weight of hollow ceramic microspheres and 10-20 parts by weight of aluminum silicate fibers are added and stirring is continued for 0.5-1 hour to obtain a thermal insulation coating.

[0026] In this embodiment, the diameter of the hollow ceramic microspheres is 100-110 μm;

[0027] The particle size of nano α-alumina powder is 50-80nm;

[0028] The particle size of nano-rutile titanium dioxide is 30-50nm.

[0029] Based on the above content, the embodiments and comparative examples of the present application are proposed. The composition of the thermal insulation coatings described in the embodiments and comparative examples of the present application is shown in Table 1.

[0030] Table 1

[0031]

[0032]

[0033] After cleaning and drying the surface of the steel plate, the surface of the steel plate is polished and roughened to ensure that the surface roughness is within the range of 25-40 μm. The thermal insulation coating prepared in the embodiment and the comparative example is applied to the clean steel plate surface with a coating thickness of 2 mm. After being left for 24 hours until the coating film is dry and solidified, the mechanical properties of the thermal insulation coating are tested. The test standards and test results are shown in Table 2.

[0034] Table 2

[0035]

[0036] According to the above test results, the thermal insulation coatings prepared in Examples 1-3 of the present application have better flexibility than the control examples, which is beneficial to preventing cracks from forming in the thermal insulation coatings after construction and curing.

[0037] Of course, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A heat-insulating coating with high temperature resistance and low thermal conductivity, characterized in that: The following raw materials are included in parts by weight: The organosilicon-modified phenolic resin is prepared by the following method: preparing a catalyst, formaldehyde, a phenolic compound, polyether silicone oil, and polyether polyol, adding a catalyst sodium hydroxide to the phenolic compound, raising the temperature to 45°C, adding polyether silicone oil and polyether polyol, and reacting at 40-50°C for 1 hour; then adding formaldehyde and continuing the reaction at a temperature of 60-65°C for 2 hours, refluxing at a temperature of 80-90°C for 1 hour, and cooling and discharging.

2. The high temperature resistant, low thermal conductivity thermal insulation coating according to claim 1, characterized in that: The relative molecular mass of the polyether polyol is 1000-2000, and the hydroxyl value is 350-500 mgKOH / g.

3. The high temperature resistant, low thermal conductivity thermal insulation coating according to claim 1, characterized in that: The phenolic compound is one or more of phenol, bisphenol A and hydroquinone.

4. The high temperature resistant, low thermal conductivity thermal insulation coating according to claim 1, characterized in that: The inorganic silicate solution is a sodium-lithium silicate composite solution.

5. A method for preparing the high temperature resistant, low thermal conductivity thermal insulation coating according to claim 1, characterized in that: include: After mixing 10-20 parts by weight of an inorganic silicate solution, 10-15 parts by weight of an organosilicon-modified phenolic resin and 10-15 parts by weight of water, the mixture is rapidly stirred at high temperature for 0.5-1 hour until the mixture is stirred and matured. After adding 20-25 parts by weight of a thickener, 3-5 parts by weight of nano-α-alumina powder, 3-4 parts by weight of nano-rutile titanium dioxide, 1-2 parts by weight of a dispersant and 1-2 parts by weight of a flame retardant, the mixture is stirred for 0.5-1 hour. Then, 30-50 parts by weight of hollow ceramic microspheres and 10-20 parts by weight of aluminum silicate fibers are added and the stirring is continued for 0.5-1 hour to obtain a thermal insulation coating.

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