CN116925613B - A self-cleaning anti-crack thermal insulation spray material and its preparation method and application - Google Patents

Abstract

The invention discloses a self-cleaning anti-cracking heat-insulating spraying material, a preparation method and application thereof. The first component comprises 45-85 parts by weight of hydrophobic polymer emulsion and 35-85 parts by weight of water. The second component comprises 16-38 parts by weight of cement, 38-68 parts by weight of filler and modified inert heat absorbing material, the mixing amount of the modified inert heat absorbing material is 3-15% of the mass of the spraying material, the modified inert heat absorbing material is a core-shell structure formed by inert heat absorbing material particles and a surface coating layer thereof, the coating layer comprises an inorganic powder layer on the surfaces of the inert heat absorbing material particles and a flexible film layer formed by partially distributing the outer surface layer of the inorganic powder layer in a water-based polymer film, and therefore double coating layers are formed on the surfaces of the inert heat absorbing material particles. The invention effectively solves the problem that the traditional inert heat absorbing material is not easy to be uniformly dispersed in the cement base material by carrying out the sexual modification on the inert heat absorbing material.

Description

A self-cleaning anti-crack thermal insulation spray material and its preparation method and application

Technical Field

The invention relates to the technical field of building thermal insulation spray materials, and in particular to a self-cleaning anti-cracking thermal insulation spray material and a preparation method and application thereof.

Background Art

The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

With the development of society, the scale of urbanization in my country has been continuously expanding, and the number of commercial housing in cities has been increasing year by year. At present, the following problems still exist in the use of commercial housing in cities: (1) Due to factors such as uneven foundation settlement, thermal expansion and contraction, and seasonal construction, cracks in the roof can easily occur. Once cracks occur, it is easy to cause water seepage and leakage in the building; (2) Since the roof is directly exposed to the sun for a long time, the temperature of the top floor is relatively high, so the insulation of the top floor is an urgent problem to be solved.

The traditional method of leakproofing and heat insulation for the top floor is mainly to lay a leakproof insulation layer, but this type of material layer is mainly made of organic materials, which has poor durability and will generally peel and crack after 3-5 years, losing its protective function. In addition, this type of material has poor fire resistance and low safety. In response to the above problems, the market has also adopted the method of using insulation bricks and steel frame awnings to prevent leaks and heat insulation on the roof, but this method is not only costly, but also affects roof activities and is not beautiful enough, and is gradually being eliminated by the market.

At present, some researchers have developed cement-based organic-inorganic composite leakproof heat-insulating spray material layers based on existing organic leakproof heat-insulating spray material layers. This technology mainly adds inert heat-absorbing materials such as carbon black or iron oxide black to the spray material layer, so as to store the heat generated by sunlight in the spray material layer while ensuring the durability of the inorganic material, thereby reducing the heat of the concrete layer and thus reducing the temperature in the house. However, the present invention finds that the important problem with this method is that carbon black has strong surface affinity and adsorption, and is extremely difficult to disperse evenly in cement-based materials. Once it is unevenly dispersed, the heat-absorbing materials will be concentrated and agglomerated, which will lead to heat concentration in some areas of the spray material layer. In this case, it is easy to cause cracks in these areas, and eventually the spray material layer will lose its function.

Summary of the invention

In view of this, the present invention provides a self-cleaning anti-crack thermal insulation spray material and its preparation method and application. The present invention effectively overcomes the problem that traditional inert heat-absorbing materials are not easy to be evenly dispersed in cement substrates by modifying the properties of inert heat-absorbing materials. To achieve the above purpose, the present invention discloses the technical solution as shown below.

In the first aspect, the present invention discloses a self-cleaning anti-crack thermal insulation spray material, comprising a first component and a second component that are separated. The first component comprises: 45 to 85 parts by weight of a hydrophobic polymer emulsion, and 35 to 85 parts by weight of water. The second component comprises: 16 to 38 parts by weight of cement, 38 to 68 parts by weight of filler, and a modified inert heat-absorbing material. The amount of the modified inert heat-absorbing material is 3 to 15% of the total mass of the first component and the second component. The modified inert heat-absorbing material is a core-shell structure formed by inert heat-absorbing material particles and their surface coating layer, and the coating layer comprises an inorganic powder layer on the surface of the inert heat-absorbing material particles and a flexible film layer formed by the outer surface layer of the inorganic powder layer being distributed in an aqueous polymer film, thereby forming a double coating layer on the surface of the inert heat-absorbing material particles.

Furthermore, the hydrophobic polymer emulsion is polyacrylate emulsion (PA), and the solid content of the polymer emulsion is 48-65%. After film formation, the hydrophobic polymer emulsion not only makes the spraying material layer have good toughness, but also has hydrophobicity, which helps to achieve self-cleaning.

Furthermore, the filler includes any one of fly ash, silica ash, silicon dioxide powder, talcum powder, mica powder, calcium carbonate powder, etc. Optionally, the 150 mesh sieve residue of the filler is between 0.5 and 2.0%. The filler is filled in the gaps in the coating, which can effectively prevent the volume shrinkage problem caused by the spraying material after curing and avoid cracking of the spraying material layer.

Furthermore, the particle size of the modified inert heat-absorbing material is between 1 and 5 mm. It should be understood that this is only an exemplary description, and the modified inert heat-absorbing material with a suitable particle size can also be selected according to specific needs.

Furthermore, the ratio of the inert endothermic material, the inorganic powder, and the aqueous polymer is 5 to 17.5 parts by weight: 10 to 25 parts by weight: 5 to 30 parts by weight. Preferably, the content of the inorganic powder is greater than the content of the inert endothermic material, so as to more completely coat the surface of the inert endothermic material particles.

Furthermore, the inert heat-absorbing material includes any one of carbon black, black iron oxide, graphite, etc. These materials are not only very stable to light and heat, not easy to age and fail, but also have good heat absorption and heat storage characteristics. In addition, the present invention also utilizes the high adsorption capacity of these inert heat-absorbing materials to adsorb the inorganic powder, which helps the inorganic powder to be more firmly coated on the surface of the inert heat-absorbing material particles.

Furthermore, the inorganic powder includes any one of metakaolin, bentonite, clay and the like.

Furthermore, the water-based polymer includes any one of polyvinyl alcohol rubber powder (PVA), polyvinyl pyrrolidone rubber powder (PVP), etc.

Furthermore, the first component also includes a liquid additive, which mainly includes at least one of 0.25 to 0.75 parts by weight of a water reducer, 0.75 to 2.25 parts by weight of an interface enhancer, etc. Optionally, the water reducer includes any one of a polycarboxylic acid water reducer, a naphthalene water reducer, etc. The interface enhancer includes any one of a silane coupling agent KH-570, polyvinyl acetate, etc.

Furthermore, the second component also includes a solid auxiliary agent, which mainly includes at least one of 0.58 to 1.62 parts by weight of a defoamer, 0.42 to 1.18 parts by weight of an early strength agent, etc. Optionally, the defoamer includes any one of acetylene glycol, polyether, tributyl phosphate, etc. The early strength agent includes any one of calcium formate, lithium carbonate, etc.

Furthermore, the preparation method of the modified inert endothermic material comprises the following steps:

(1) Wetting the inert endothermic material particles and mixing with inorganic powder for coating, so that the inorganic powder is coated on the surface of the inert endothermic material to obtain core-shell precursor particles for later use.

(2) coating the aqueous polymer powder on the surface of the core-shell precursor particles, and then drying the aqueous polymer powder to form a film, thereby obtaining a modified inert endothermic material.

Furthermore, in step (1), the particle size of the inert endothermic material particles is larger than that of the inorganic powder, so that the inorganic powder can be adsorbed and coated on the surface of the inert endothermic material particles. Optionally, the particle size of the inorganic powder is between 1500 and 2000 mesh, and the particle size of the inert endothermic material is between 30 and 100 mesh.

Furthermore, in step (1), the inert endothermic material is placed in an environment with a humidity of 53 to 58% and allowed to stand for 1.8 to 2.1 hours, so that water vapor is adsorbed on the surface of the inert endothermic material to moisten it, or the inert endothermic material can be moistened by spraying water into the inert endothermic material so that the inorganic powder adheres to the surface of the inert endothermic material.

Furthermore, in step (1), the inert endothermic material particles are evenly sprinkled on the flat inorganic powder layer, and then vibration granulation is performed to coat the inorganic powder on the surface of the inert endothermic material particles. After completion, the product is allowed to stand for 1 to 2 hours to stabilize its structure, thereby obtaining the core-shell precursor particles.

Furthermore, in step (2), the core-shell precursor particles are evenly sprinkled on the flat aqueous polymer powder layer, and then vibrated to granulate, so that the inorganic powder is coated on the surface of the inert endothermic material particles. Preferably, the ambient humidity of this step is not greater than 35%, so as to prevent the aqueous polymer from excessively absorbing water and emulsifying.

Furthermore, in step (2), the drying temperature is 50-55° C. and the drying time is 23-25 hours.

In a second aspect, the present invention discloses a method for preparing the self-cleaning anti-crack thermal insulation spray material, comprising:

(i) The raw materials of the first component are mixed evenly to form component A, and the raw materials of the second component are mixed evenly to form component B, and the mixture is set aside.

(ii) Before use, the component A and the component B are mixed evenly to obtain a self-cleaning anti-cracking thermal insulation spray material.

It should be understood that the preparation order of the components A and B is not particularly limited, and the component A can be prepared first and then the component B, or the component B can be prepared first and then the component A, or the components A and B can be prepared simultaneously.

In a third aspect, the present invention discloses the application of the self-cleaning anti-crack thermal insulation spray material in the fields of construction, bridges, etc.

Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

As mentioned above, since inert heat-absorbing materials such as carbon black or iron oxide black are not easy to be evenly dispersed in cement-based materials, the existing organic-inorganic composite leak-proof heat-insulating spray material layer is prone to cracking due to local excessive temperature caused by the concentrated distribution of inert heat-absorbing materials, which eventually causes the leakage-proof function of the coating to fail, and the service life of the spray material is significantly shortened due to the appearance of such abnormal factors. For this reason, the present invention modifies the inert heat-absorbing material and effectively overcomes the above problems. In order to achieve the above purpose, the present invention first uses inorganic powder to coat the inert heat-absorbing material particles to form a modified inert heat-absorbing material with a core-shell structure. After the present invention uses it as a component of the spray material, it is found that there is still a serious problem of agglomeration. After analysis, it is found that this is mainly because the inorganic powder coated on the surface of the inert heat-absorbing material particles after mixing and stirring with the cement substrate is easy to fall off, resulting in the rapid exposure of the inert heat-absorbing material.

To this end, the present invention uses an aqueous polymer to further modify the above-mentioned modified inert heat-absorbing material, and uses the water adsorbed by the modified inert heat-absorbing material in the early coating process to emulsify the aqueous polymer after coating, and after drying and film formation, a flexible polymer film layer is formed again on the surface of the inorganic powder coating layer of the modified inert heat-absorbing material, that is, a double-coated layer modified inert heat-absorbing material, which can effectively prevent the inorganic powder coating layer from falling off. The surface of this double-coated layer modified inert heat-absorbing material shows good inertness to cement particles, effectively avoiding the problem that traditional inert heat-absorbing materials are not easy to disperse evenly in cement substrates. In addition, since the polymer film layer is doped with inorganic powder particles, it also has good wear resistance and strength, so that the double-coated layer modified inert heat-absorbing material is not easy to break during the stirring and mixing process after being added to the cement substrate, and maintains a good coating state, avoiding the problem of inert failure of cement particles caused by mechanical damage.

Furthermore, in order to make the double-coated modified inert heat-absorbing material release the inert heat-absorbing material after mixing with other materials, the spraying material of the present invention adopts a first component including a hydrophobic polymer emulsion and water. Since the water-based polymer has good compatibility with the first component, after the first component and the second component are evenly mixed, the water-based polymer gradually dissolves under the action of the first component and enters the spraying material to absorb moisture, thereby promoting the formation of a film on the surface of the hydrophobic polymer emulsion. After the water-based polymer is dissolved, the inorganic powder is exposed and then gradually disintegrates and falls off into the spraying material as a filler to increase the volume stability of the spraying material during the hardening process, and expose the inert heat-absorbing material, which is evenly distributed in the spraying material layer, and has the ability to uniformly absorb heat and keep warm after the spraying material layer is hardened. At the same time, after the hydrophobic polymer emulsion in the spraying material forms a film, the spraying material has good hydrophobic properties, which helps the self-cleaning of the surface of the spraying material. In addition, the hydrophobic polymer emulsion in the spray material of the present invention can effectively enhance the fracture toughness of the cement substrate after film formation, so that the spray material of the present invention has good crack resistance. In addition, the spray material of the present invention also has the advantages of good flame retardancy, high bonding strength, fast construction speed, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of the specification of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute an improper limitation of the present invention. The embodiments of the present invention are described in detail below in conjunction with the drawings, wherein:

FIG. 1 is a SEM image of the sprayed material prepared in Example 5 below.

FIG. 2 is a SEM image of the sprayed material prepared in Example 6 below.

FIG. 3 is a SEM image of the sprayed material prepared in Example 8 below.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.

Unless otherwise defined, all professional and scientific terms used in the present invention have the same meanings as those familiar to those skilled in the art. The reagents or raw materials used in the present invention can be purchased through conventional channels. If there are no special instructions, the reagents or raw materials used in the present invention are used in a conventional manner in the art or in accordance with the product instructions. In addition, any method and material similar to or equivalent to the described content can be applied to the method of the present invention. The preferred implementation methods and materials described in the present invention are for demonstration purposes only.

Example 1

1. A method for preparing a double-coated modified inert heat-absorbing material, comprising the following steps:

(1) Prepare the following raw materials in a weight ratio: carbon black particles with a particle size of 50 mesh: metakaolin powder with a particle size of 1800 mesh: polyvinyl alcohol rubber powder (PVA-1788) = 15:18:14. The fineness of the polyvinyl alcohol rubber powder is 250 mesh (sieve residue ≤ 4%).

(2) The carbon black particles are allowed to stand for 2 hours in a room temperature environment with a humidity of 55%, and the carbon black particles are allowed to absorb water and moisten by virtue of their good adsorption capacity. Then, the metakaolin is spread on a tray of a horizontal decolorizing shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the wetted carbon black particles are sprinkled on the metakaolin layer. The horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes. After completion, the product is removed and allowed to stand for 2 hours, and core-shell precursor particles are obtained for standby use.

(3) The polyvinyl alcohol rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the core-shell precursor particles are sprinkled on the polyvinyl alcohol rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 160 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 50°C for 24 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 1 to 2 mm are screened out for use.

2. A method for preparing a self-cleaning anti-crack thermal insulation spray material, comprising the following steps:

(i) Prepare the following raw materials as the first component: 51 parts by weight of polyacrylate emulsion (PA) with a solid content of 58% and 48 parts by weight of clean water. Mix the raw materials of the first component and disperse them by ultrasonic for 15 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 20 parts by weight of 42.5 ordinary Portland cement, 45 parts by weight of silica fume, and the double-coated modified inert heat-absorbing material prepared in this example. The amount of the double-coated modified inert heat-absorbing material is 10% of the total mass of the first component and the second component, and the 150-mesh residue of the silica fume is 2.0%. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested. Among them: elongation at break and tensile strength were measured according to the standard of ASTM D638. The bonding strength was measured according to the standard of GB/T23445-2009. The surface contact angle test used an optical contact angle meter (JC2000D3A) produced by Shanghai Zhongchen Digital Technology Equipment Co., Ltd. to measure the contact angle of the material of the present invention, and the five-point fitting method was used to analyze the picture. The water drop size used in the measurement process was 4uL, and five measurement results were averaged. The thermal conductivity was measured according to the standard of ISO 22007-2; the flame retardant grade was according to GB/T 8624-2012. The rebound rate was measured according to the standard of JGJ/T 372-2016.

The test results are shown in the following table.

Example 2

1. A method for preparing a double-coated modified inert heat-absorbing material, comprising the following steps:

(1) Prepare the following raw materials in a weight ratio: black iron oxide particles with a particle size of 100 mesh: bentonite powder with a particle size of 2000 mesh: polyvinyl alcohol rubber powder (PVA-2488) = 12:25:20. The polyvinyl alcohol rubber powder has a fineness of 250 mesh (sieve residue ≤ 4%).

(2) The black iron oxide particles were allowed to stand for 2.1 hours in a room temperature environment with a humidity of 53%, and the black iron oxide particles were used to absorb water and moisten by virtue of their good adsorption capacity. The bentonite was then spread on a tray of a horizontal decolorizing shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the wetted black iron oxide particles were sprinkled on the bentonite layer. The horizontal decolorizing shaker was started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes. After completion, the product was removed and allowed to stand for 1.5 hours, and core-shell precursor particles were obtained for standby use.

(3) The polyvinyl alcohol rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the core-shell precursor particles are sprinkled on the polyvinyl alcohol rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 160 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 50°C for 25 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 3 to 5 mm are screened out for use.

2. A method for preparing a self-cleaning anti-crack thermal insulation spray material, comprising the following steps:

(i) Prepare the following raw materials as the first component: 45 parts by weight of polyacrylate emulsion (PA) with a solid content of 65% and 50 parts by weight of clean water. Mix the raw materials of the first component and disperse them by ultrasonic for 15 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 25 parts by weight of 42.5 ordinary Portland cement, 53 parts by weight of mica powder and the double-coated modified inert heat-absorbing material prepared in this example. The double-coated modified inert heat-absorbing material is added in an amount of 8% of the total mass of the first component and the second component, and the 150-mesh residue of the silica fume is 1.8%. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 3

1. A method for preparing a double-coated modified inert heat-absorbing material, comprising the following steps:

(1) Prepare the following raw materials in a weight ratio: graphite particles with a particle size of 30 mesh: clay powder with a particle size of 1500 mesh: polyvinyl alcohol rubber powder (PVA-2488) = 17.5:25:30. The polyvinyl alcohol rubber powder has a fineness of 250 mesh (sieve residue ≤ 4%).

(2) The graphite particles were allowed to stand for 1.8 hours in a room temperature environment with a humidity of 58%, and the graphite particles were allowed to absorb water and moisten by virtue of their good adsorption capacity. The clay was then spread on a tray of a horizontal decolorization shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the wetted graphite particles were sprinkled on the clay layer. The horizontal decolorization shaker was started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes. After completion, the product was removed and allowed to stand for 1 hour, and core-shell precursor particles were obtained for standby use.

(3) The polyvinyl alcohol rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the core-shell precursor particles are sprinkled on the polyvinyl alcohol rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 55°C for 23 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 2 to 4 mm are screened out for use.

2. A method for preparing a self-cleaning anti-crack thermal insulation spray material, comprising the following steps:

(i) Prepare the following raw materials as the first component: 60 parts by weight of polyacrylate emulsion (PA) with a solid content of 48% and 85 parts by weight of clean water. Mix the raw materials of the first component and disperse them by ultrasonic for 15 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 30 parts by weight of 42.5 ordinary Portland cement, 55 parts by weight of fly ash and the double-coated modified inert heat-absorbing material prepared in this example. The double-coated modified inert heat-absorbing material is added in an amount of 12% of the total mass of the first component and the second component, and the fly ash has a 150-mesh sieve residue of 0.7%. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 4

1. A method for preparing a double-coated modified inert heat-absorbing material, comprising the following steps:

(1) Prepare the following raw materials in a weight ratio: carbon black particles with a particle size of 40 mesh: bentonite powder with a particle size of 2000 mesh: polyvinyl pyrrolidone rubber powder (PVP-K30) = 5:10:5. The polyvinyl pyrrolidone rubber powder has a fineness of 250 mesh (sieve residue ≤ 4%).

(2) The carbon black particles are allowed to stand for 2 hours in a room temperature environment with a humidity of 55%, and the carbon black particles are moistened by absorbing water using their good adsorption capacity. Then the bentonite is spread on a tray of a horizontal decolorization shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the moistened carbon black particles are sprinkled on the bentonite layer. The horizontal decolorization shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes. After completion, the product is removed to obtain core-shell precursor particles for standby use.

(3) The polyvinyl pyrrolidone rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the core-shell precursor particles are sprinkled on the polyvinyl pyrrolidone rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 50°C for 24 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 2 to 3 mm are screened out for use.

2. A method for preparing a self-cleaning anti-crack thermal insulation spray material, comprising the following steps:

(i) Prepare the following raw materials as the first component: 45 parts by weight of polyacrylate emulsion (PA) with a solid content of 58%, 35 parts by weight of clean water, 0.25 parts by weight of polycarboxylic acid water reducer (water reduction rate of 20%), and 0.75 parts by weight of silane coupling agent (KH-570). Mix the raw materials of the first component and then disperse them by ultrasonic for 15 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 16 parts by weight of 42.5 ordinary Portland cement, 38 parts by weight of silica powder, 0.58 parts by weight of defoamer, 0.42 parts by weight of early strength agent and the double-coated modified inert heat-absorbing material prepared in this embodiment. The amount of the double-coated modified inert heat-absorbing material is 3% of the total mass of the first component and the second component, the 150-mesh residue of the silica powder is 0.5%, the defoamer is polyether, and the early strength agent is calcium formate. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 5

1. A method for preparing a double-coated modified inert heat-absorbing material, comprising the following steps:

(1) Prepare the following raw materials in a weight ratio: carbon black particles with a particle size of 80 mesh: clay powder with a particle size of 1600 mesh: polyvinyl pyrrolidone rubber powder (PVP-K30) = 15:10:12. The fineness of the polyvinyl pyrrolidone rubber powder is 250 mesh (sieve residue ≤ 4%).

(2) The carbon black particles were placed in a room temperature environment with a humidity of 55% for 2 hours to absorb water and moisten the carbon black particles by using their good adsorption capacity. The clay was then spread on a tray of a horizontal decolorization shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the wetted carbon black particles were sprinkled on the clay layer. The horizontal decolorization shaker was started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 200 rpm for another 5 minutes. After completion, the product was removed to obtain core-shell precursor particles for standby use.

(3) The polyvinyl alcohol rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the core-shell precursor particles are sprinkled on the polyvinyl alcohol rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 160 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 50°C for 24 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 3 to 4 mm are screened out for use.

2. A method for preparing a self-cleaning anti-crack thermal insulation spray material, comprising the following steps:

(i) Prepare the following raw materials as the first component: 85 parts by weight of polyacrylate emulsion (PA) with a solid content of 58%, 75 parts by weight of clean water, 0.75 parts by weight of polycarboxylic acid water reducer (water reduction rate of 25%), and 2.25 parts by weight of polyvinyl acetate interface. Mix the raw materials of the first component and then disperse them by ultrasonic for 25 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 38 parts by weight of 42.5 ordinary Portland cement, 68 parts by weight of talcum powder, 1.62 parts by weight of defoamer, 1.18 parts by weight of early strength agent and the double-coated modified inert heat-absorbing material prepared in this embodiment. The amount of the double-coated modified inert heat-absorbing material is 15% of the total mass of the first component and the second component, the 150-mesh residue of the talcum powder is 1.2%, the defoamer is polyether, and the early strength agent is lithium carbonate. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 6

A method for preparing a self-cleaning anti-crack thermal insulation spray material is the same as that of Example 1, except that a single-coating modified inert heat-absorbing material prepared by the following method is used instead of the double-coating modified inert heat-absorbing material. Specifically, the method comprises the following steps:

(1) Prepare the following raw materials in a weight ratio: carbon black particles with a particle size of 50 mesh: kaolin powder with a particle size of 1800 mesh = 15:18.

(2) The carbon black particles are allowed to stand for 2 hours in a room temperature environment with a humidity of 55%, and the carbon black particles are wetted by absorbing water using their good adsorption capacity. Then, the metakaolin is spread on a tray of a horizontal decolorizing shaker of model NSP300 to form a plane with a thickness of about 1 mm, and the wetted carbon black particles are sprinkled on the metakaolin layer. The horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes. After completion, the product is removed to obtain single-coated layer modified inert endothermic material particles.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 7

A method for preparing a self-cleaning anti-crack thermal insulation spray material is the same as that of Example 2, except that a single-coating modified inert heat-absorbing material prepared by the following method is used to replace the double-coating modified inert heat-absorbing material. Specifically, the method comprises the following steps:

(1) Prepare the following raw materials in a weight ratio: black iron oxide particles with a particle size of 100 mesh: polyvinyl alcohol rubber powder (PVA-2488) = 12:20. The polyvinyl alcohol rubber powder has a fineness of 250 mesh (sieve residue ≤ 4%).

(2) The polyvinyl alcohol rubber powder is spread flat on the tray of the horizontal decolorizing shaker to form a plane with a thickness of about 1 mm, and then the black iron oxide particles are sprinkled on the polyvinyl alcohol rubber powder layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 160 rpm for another 5 minutes (the ambient humidity of the above steps is not more than 35%). After completion, the product is taken out and dried in an oven at 50°C for 24 hours to obtain a single-coated layer modified inert heat-absorbing material, and particles with a particle size of 3 to 5 mm are screened out for use.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 8

A method for preparing a self-cleaning anti-crack thermal insulation spray material comprises the following steps:

(i) Prepare the following raw materials as the first component: 60 parts by weight of polyacrylate emulsion (PA) with a solid content of 58% and 85 parts by weight of clean water. Mix the raw materials of the first component and disperse them by ultrasonic for 15 minutes to obtain component A, which is sealed and stored for later use.

(ii) Prepare the following raw materials as the second component: 30 parts by weight of 42.5 ordinary Portland cement, 55 parts by weight of fly ash and carbon black particles with a size of 2 to 4 mm. The amount of carbon black is 12% of the total mass of the first component and the second component, and the 150-mesh residue of the fly ash is 0.7%. Mix the raw materials of the second component and mechanically stir for 3 minutes to obtain component B, which is sealed and stored for later use.

(iii) The A component and the B component are placed in a stirrer and mixed at a rate of 1200 r/min for 10 min to obtain a self-cleaning anti-cracking thermal insulation spray material.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

Example 9

A method for preparing a self-cleaning anti-crack thermal insulation spray material is the same as that of Example 4, except that a single-coating modified inert heat-absorbing material prepared by the following method is used instead of the double-coating modified inert heat-absorbing material. Specifically, the method comprises the following steps:

(1) Prepare the following raw materials in a weight ratio: carbon black particles with a particle size of 40 mesh: bentonite powder with a particle size of 2000 mesh: polyvinyl pyrrolidone rubber powder (PVP-K30) = 5:10:5. The polyvinyl pyrrolidone rubber powder has a fineness of 250 mesh (sieve residue ≤ 4%).

(2) The carbon black particles are allowed to stand for 2 hours in a room temperature environment with a humidity of 55%, and the carbon black particles are moistened by absorbing water using their good adsorption capacity. Then, the bentonite and polyvinyl pyrrolidone rubber powder are mixed for 10 minutes to form a mixture, and the mixture is spread on the tray of a horizontal decolorizing shaker of model NSP300 to form a plane with a thickness of about 1 mm. The moistened carbon black particles are sprinkled on the bentonite layer, and the horizontal decolorizing shaker is started to work at a speed of 80 rpm for 5 minutes, and then at a speed of 210 rpm for another 5 minutes (the ambient humidity of the above steps is not greater than 35%). After completion, the product is removed and dried in an oven at 50°C for 24 hours to obtain a double-coated modified inert endothermic material, and particles with a particle size of 2 to 3 mm are screened out for use.

The various mechanical properties of the spraying material finally prepared in this embodiment were tested (the testing method was the same as that of the above-mentioned embodiment 1), and the test results are shown in the following table.

FIG1 is a SEM image of the spray material prepared in Example 5 above, from which it can be seen that the carbon black particles are evenly dispersed in the film structure after the emulsion is cured and are tightly embedded in the polymer film, ensuring that the material has good mechanical properties and uniform thermal conductivity.

FIG2 is a SEM image of the spray material prepared in Example 6, where it can be seen that the carbon black particles are slightly agglomerated and not embedded in the polymer film. This indicates that if the carbon black surface is not coated with PVA rubber powder, the core-shell structure of the prepared modified inert heat-absorbing material will be unstable, and the core-shell structure will be easily broken and lose the function of preventing carbon black particles from agglomerating. After agglomeration, it is easy to cause local overheating and cracking of the spray material when heated, and it will be separated from the polymer film, affecting the mechanical properties of the spray material.

FIG3 is an SEM image of the spray material prepared in Example 8 above. It can be seen that the carbon black particles are agglomerated over a large area. This indicates that if only ordinary unmodified carbon black particles are used to replace the double-coated modified inert heat-absorbing material, the carbon black particles will have a strong attraction between the particles and are easy to aggregate, resulting in serious agglomeration, which will lead to the deterioration of the mechanical properties and thermal conductivity of the spray material.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (24)

1. The self-cleaning anti-cracking heat-insulating spraying material is characterized by comprising a first component and a second component; wherein:

The first component comprises 45-85 parts by weight of hydrophobic polymer emulsion and 35-85 parts by weight of water; the aqueous polymer comprises: any one of polyvinyl alcohol rubber powder and polyvinylpyrrolidone rubber powder;

The second component comprises 16-38 parts by weight of cement, 38-68 parts by weight of filler and modified inert heat absorbing material; the mixing amount of the modified inert heat absorbing material is 3-15% of the total mass of the first component and the second component; the inert heat sink material comprises: any one of carbon black, iron oxide black and graphite;

The modified inert heat absorbing material is a core-shell structure formed by inert heat absorbing material particles and a surface coating layer thereof;

The coating layer comprises an inorganic powder layer on the surface of the inert heat absorbing material particles and a flexible film layer formed by partially distributing the outer surface layer of the inorganic powder layer in the water-based polymer film, so that a double coating layer is formed on the surface of the inert heat absorbing material particles.

2. The self-cleaning anti-cracking heat-insulating spraying material according to claim 1, wherein the hydrophobic polymer emulsion is polyacrylate emulsion, and the solid content of the polymer emulsion is 48-65%.

3. The self-cleaning anti-crack thermal insulation spray material of claim 1, wherein the filler comprises: fly ash, silica fume, silicon dioxide powder, talcum powder, mica powder and calcium carbonate powder.

4. The self-cleaning anti-cracking thermal insulation spraying material according to claim 1, wherein 150 mesh screen residue of the filler is 0.5-2.0%.

5. The self-cleaning anti-cracking heat-insulating spraying material according to claim 1, wherein the particle size of the modified inert heat-absorbing material is 1-5 mm.

6. The self-cleaning anti-cracking heat-insulating spraying material according to claim 1, wherein the proportion of the inert heat-absorbing material, the inorganic powder and the water-based polymer is 5-17.5 parts by weight: 10-25 parts by weight of: 5-30 parts by weight of a base material.

7. The self-cleaning anti-cracking thermal insulation spray material according to claim 1, wherein the inorganic powder content is greater than the inert heat absorbing material content.

8. The self-cleaning type crack-resistant thermal insulation spray material according to claim 1, wherein the inorganic powder comprises: any one of metakaolin, bentonite and clay.

9. The self-cleaning anti-cracking heat-insulating spraying material according to claim 1, wherein the first component further comprises a liquid auxiliary agent, and the liquid auxiliary agent mainly comprises at least one of 0.25-0.75 parts by weight of a water reducing agent and 0.75-2.25 parts by weight of an interface reinforcing agent.

10. The self-cleaning type anti-cracking heat-insulating spraying material according to claim 9, wherein the water reducing agent comprises any one of a polycarboxylic acid water reducing agent and a naphthalene water reducing agent.

11. The self-cleaning type anti-cracking thermal insulation spraying material according to claim 9, wherein the interface enhancer comprises any one of silane coupling agent KH-570 and polyvinyl acetate.

12. The self-cleaning anti-cracking heat-insulating spraying material according to claim 1, wherein the second component further comprises a solid auxiliary agent, and the solid auxiliary agent mainly comprises at least one of 0.58-1.62 parts by weight of an antifoaming agent and 0.42-1.18 parts by weight of an early strength agent.

13. The self-cleaning anti-cracking thermal insulation spray material of claim 12, wherein the defoamer comprises any of acetylenic diol, polyether, tributyl phosphate.

14. The self-cleaning type anti-cracking heat-insulating spraying material according to claim 12, wherein the early strength agent comprises any one of calcium formate and lithium carbonate.

15. The self-cleaning anti-cracking thermal insulation spray material according to any one of claims 1-14, wherein the preparation method of the modified inert heat absorbing material comprises the following steps:

(1) The inert heat absorbing material particles are mixed with inorganic powder for coating after being wetted, so that the inorganic powder is coated on the surface of the inert heat absorbing material to obtain core-shell type precursor particles for later use;

(2) Coating the water-based polymer powder on the surface of the core-shell precursor particles, and then drying to form a film of the water-based polymer powder, thus obtaining the modified inert heat absorbing material.

16. The self-cleaning type crack-resistant thermal insulation spray material according to claim 15, wherein in the step (1), the particle size of the inert heat absorbing material particles is larger than that of the inorganic powder.

17. The self-cleaning anti-cracking thermal insulation spraying material according to claim 15, wherein in the step (1), the particle size of the inorganic powder is 1500-2000 meshes, and the particle size of the inert heat absorbing material is 30-100 meshes.

18. The self-cleaning anti-cracking thermal insulation spraying material according to claim 15, wherein in the step (1), the inert heat absorbing material is placed in an environment with the humidity of 53% -58% for standing for 1.8-2.1 h, or the wetting of the inert heat absorbing material is carried out by spraying water into the inert heat absorbing material until the humidity reaches 53% -58%.

19. The self-cleaning anti-cracking heat-insulating spraying material according to claim 15, wherein in the step (1), the inert heat-absorbing material particles are uniformly scattered on a tiled inorganic powder layer, vibration granulation is carried out, so that the inorganic powder is coated on the surfaces of the inert heat-absorbing material particles, and the core-shell precursor particles are obtained after standing for 1-2 hours.

20. The self-cleaning anti-cracking thermal insulation spray coating material according to claim 15, wherein in step (2), the core-shell type precursor particles are uniformly scattered on a flat water-based polymer powder layer, and then vibration granulation is carried out, wherein the water-based polymer powder is coated on the surfaces of the core-shell type precursor particles.

21. The self-cleaning anti-crack thermal insulation spray material of claim 20, wherein the ambient humidity is no greater than 35%.

22. The self-cleaning anti-cracking thermal insulation spraying material according to claim 15, wherein in the step (2), the drying temperature is 50-55 ℃ and the time is 23-25 h.

23. The method for preparing the self-cleaning anti-cracking thermal insulation spraying material according to any one of claims 1 to 22, which is characterized by comprising the following steps:

(i) Uniformly mixing all the raw materials of the first component to form a component A;

Uniformly mixing the raw materials of the second component to form a component B;

(ii) And (3) before use, uniformly mixing the component A and the component B to obtain the self-cleaning anti-cracking heat-insulating spraying material.

24. The use of the self-cleaning anti-cracking thermal insulation spray material according to any one of claims 1 to 22 or the self-cleaning anti-cracking thermal insulation spray material obtained by the preparation method according to claim 23 in the field of buildings or bridges.