Polyurea thermal insulation coating and preparation method thereof

Abstract

The invention discloses a polyurea heat insulation coating which comprises a component A and a component B, the component A is prepared from the following components in parts by mass: 40 to 60 parts of modified polyurea resin, 6 to 14 parts of heat insulation filler, 1 to 12 parts of fluxing agent, 7 to 23 parts of reflective functional filler and 6 to 20 parts of mica powder; the modified polyurea resin is obtained by modifying polyurea resin through graphene; the component B comprises the following components in parts by mass: 40-60 parts of a modified polyurea resin curing agent, 4-14 parts of a heat insulation filler, 2-12 parts of a fluxing agent, 6-21 parts of a reflective functional filler and 6-25 parts of mica powder; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor through hydroxyl silicone oil. The invention further discloses a preparation method of the polyurea heat insulation coating. The polyurea heat insulation coating is a non-expansive coating, has high temperature resistance and heat insulation performance, and can be used in the field of batteries.

Description

Technical Field

[0001] The invention relates to the field of coatings applied to batteries, and in particular to a polyurea thermal insulation coating and a preparation method thereof. Background Art

[0002] Paint refers to a material that is applied to the surface of an object to be protected or decorated and can form a continuous film that is firmly attached to the object. In other words, paint is a material that can be applied to the surface of an object using different construction processes to form a solid film that is firmly adhered, has a certain strength, and is continuous.

[0003] There are many types of coatings currently. In the field of thermal insulation coatings, there are intumescent thermal insulation coatings and non-intumescent thermal insulation coatings. Among them, intumescent thermal insulation coatings are the main ones. Their thermal insulation mechanism is as follows: under high temperature environment, the base material, carbon source and flame retardant in the coating are dehydrated under the action of acid source (phosphate esters are more common), and the gas source (melamine, etc.) decomposes to produce gas to make the carbon layer foam. The expanded carbon layer is loose and porous, with a low thermal conductivity coefficient, and the thicker carbon layer can effectively isolate external combustible gases and effectively flame retardant, so it can better insulate heat. Intumescent thermal insulation coatings are currently mainly used in fields such as fire protection of industrial building steel structures. From its fireproof and heat-insulating mechanism, it can be seen that intumescent thermal insulation coatings must rely on the expansion of the carbon layer after heating to form a loose and porous structure in order to play a role in fireproofing and heat insulation. Therefore, its effect is poor in some application scenarios with limited space, and it cannot effectively protect products or structures at high temperatures.

[0004] Other types of non-expanding thermal insulation coatings achieve thermal insulation by adding a large amount of low thermal conductivity fillers to the film-forming base material, but their temperature resistance is limited. At high temperatures, the structure collapses and cracks are generated, and a large amount of heat penetrates from the cracks to the protected object, resulting in failure. Or the optimized thermal insulation filler is aerogel powder, but because the viscosity of aerogel powder is very strong, the amount added is limited, and aerogel powder cannot shield thermal radiation at high temperatures (above 500°C), so a large amount of heat penetrates the aerogel in the form of thermal radiation and is transferred to the protected object, resulting in poor thermal insulation effect.

[0005] In the field of automotive batteries, power batteries are the core components of electric vehicles. The cells in power batteries have the risk of thermal runaway during long-term use. However, because they are arranged closely together, the gap between each two cells is only 1 to 3 mm, leaving no room for the intumescent thermal insulation coating to expand. In addition, the cells are bound by end plates after being assembled into modules, which means that the cells are always under stress. Therefore, intumescent thermal insulation coatings cannot be used between cells. The thermal insulation performance of current non-intumescent thermal insulation coatings cannot meet the use requirements of power batteries with high-efficiency thermal insulation performance at high temperatures.

[0006] In particular, polyurea coatings are a typical intumescent thermal insulation coating with low thermal conductivity, which can effectively reduce heat transfer. They also have good adhesion, which is conducive to the integrated molding of multiple cells in power batteries, and are highly tolerant to preparation process conditions. Therefore, it is necessary to conduct in-depth research on polyurea coatings and develop a new type of non-intumescent polyurea thermal insulation coating for automotive batteries that still has high thermal insulation performance at high temperatures. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a polyurea thermal insulation coating and a preparation method thereof.

[0008] In a first aspect, an embodiment of the present invention discloses a polyurea thermal insulation coating, including a component A and a component B;

[0009] The component A comprises, by weight: 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 1 to 12 parts of flux, 7 to 23 parts of reflective functional filler, and 6 to 20 parts of mica powder; the modified polyurea resin is obtained by modifying polyurea resin with graphene;

[0010] In parts by mass, the B component includes: 40 to 60 parts of modified polyurea resin curing agent, 4 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 6 to 21 parts of reflective functional filler, and 6 to 25 parts of mica powder; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor with hydroxy silicone oil.

[0011] By adopting the above technical scheme, the modified polyurea resin can be ceramicized at high temperature, realizing non-expansive modification, and the dense layer formed by ceramicization isolates heat convection, and the thermal insulation filler further reduces heat conduction. Combined with the reflective functional filler, the polyurea thermal insulation coating of the present invention has high heat reflection and external heat radiation capabilities, and performs all-round insulation from the three paths of "heat convection, heat conduction, and heat radiation", thereby achieving a better thermal insulation effect.

[0012] Optionally, in the component A, the modified polyurea resin includes, by mass, 80 to 120 parts of polyurea resin, 1 to 5 parts of graphene solution and 0.1 to 1.2 parts of silane coupling agent; wherein the mass fraction of graphene in the graphene solution is 0.1 to 1 wt %, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, glycerol, PEG500 polyether and PEG1000 polyether.

[0013] Optionally, in the B component, the modified polyurea resin curing agent includes, by mass, 40 to 60 parts of a polyurea resin precursor, 1 to 8 parts of acetone, 40 to 60 parts of hydroxy silicone oil, 1 to 3 parts of toluene, and 1 to 3 parts of butyl ester; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%.

[0014] Optionally, the component A and the component B satisfy at least one of the following conditions:

[0015] The thermal insulation filler comprises a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm;

[0016] The flux comprises flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1 to 1:1, the particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400° C., and the melting point of flux 2 is 400 to 600° C.;

[0017] The reflective functional filler comprises a reflective functional filler 1 and a reflective functional filler 2, wherein the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1:1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm;

[0018] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of the mica powder 1 to the mica powder 2 is 1:1 to 3:1, the particle size D50 of the mica powder 1 is 10 to 35 μm, and the particle size D50 of the mica powder 2 is 5 to 15 μm.

[0019] Optionally, in parts by mass, the component A further comprises: 5 to 10 parts of an anti-cracking functional additive, 0 to 1.5 parts of a coupling agent and 1 to 10 parts of a compound solvent; the component B further comprises: 5 to 15 parts of an anti-cracking functional additive and 0 to 1.5 parts of a coupling agent; the mass content of the coupling agent in the component A and the component B is not 0 at the same time.

[0020] Optionally, the density of the polyurea thermal insulation coating is less than 1.0 g / cm 3 .

[0021] In a second aspect, an embodiment of the present invention discloses a method for preparing a polyurea thermal insulation coating, which is used to prepare a polyurea thermal insulation coating as in any embodiment of the first aspect, comprising the following steps:

[0022] Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 7 to 23 parts of reflective functional filler and 6 to 20 parts of mica powder are mixed to obtain component A; the modified polyurea resin is obtained by modifying polyurea resin with graphene;

[0023] Preparation of component B: by weight, 40 to 60 parts of a modified polyurea resin curing agent, 4 to 14 parts of a heat insulating filler, 2 to 12 parts of a flux, 6 to 21 parts of a reflective functional filler and 6 to 25 parts of mica powder are mixed to obtain component B; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor with hydroxy silicone oil;

[0024] Preparation of polyurea thermal insulation coating: Component A and component B are mixed and cured to obtain polyurea thermal insulation coating.

[0025] By adopting the above technical scheme, the polyurea thermal insulation coating of the present invention includes component A and component B, which is convenient for regulating the viscosity of component A and component B during the preparation process, is beneficial to improving the curing film-forming performance of the polyurea thermal insulation coating of the present invention and is convenient for storage, has better processability, and is convenient for preparing a polyurea thermal insulation coating with good thermal insulation performance and non-expansive.

[0026] Optionally, at least one of the following conditions is met in the steps of preparing component A and preparing component B:

[0027] The thermal insulation filler comprises a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm;

[0028] The flux comprises flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1 to 1:1, the particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400° C., and the melting point of flux 2 is 400 to 600° C.;

[0029] The reflective functional filler comprises a reflective functional filler 1 and a reflective functional filler 2, wherein the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1:1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm;

[0030] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of the mica powder 1 to the mica powder 2 is 1:1 to 3:1, the particle size D50 of the mica powder 1 is 10 to 35 μm, and the particle size D50 of the mica powder 2 is 5 to 15 μm.

[0031] Optionally, the method for preparing the polyurea thermal insulation coating comprises the following steps:

[0032] Preparation of modified polyurea resin: After mixing 80-120 parts of polyurea resin and 1-5 parts of graphene solution by weight, 0.1-1.2 parts of silane coupling agent are added and mixed to obtain modified polyurea resin; wherein the mass fraction of graphene in the graphene solution is 0.1-1wt%, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, glycerol, PEG500 polyether and PEG1000 polyether;

[0033] Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin and 5 to 10 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 2 to 8 parts of reflective functional filler 1 and 5 to 15 parts of reflective functional filler 2 are added in sequence and mixed, and then 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 10 parts of mica powder 2 are added and mixed, and after cooling to room temperature, 1 to 10 parts of compounding solvent are mixed to obtain component A;

[0034] Preparation of modified polyurea resin curing agent: by weight, at a temperature of 60 to 90° C., 40 to 60 parts of polyurea resin precursor, 17 to 29 parts of acetone and 40 to 60 parts of hydroxy silicone oil are mixed, and after heat preservation for 3 to 5 hours, 16 to 21 parts of acetone are evaporated, and 1 to 3 parts of toluene and 1 to 3 parts of butyl ester are added and mixed to obtain a modified polyurea resin curing agent; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%;

[0035] Preparation of component B: by weight, 40 to 60 parts of modified polyurea resin curing agent and 5 to 15 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 1 to 6 parts of reflective functional filler 1, 5 to 15 parts of reflective functional filler 2, 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 15 parts of mica powder 2 are added in sequence and mixed, and after cooling to room temperature, component B is obtained;

[0036] Preparation of polyurea thermal insulation coating: Component A and component B are mixed and then cured on the surface of a template to obtain a polyurea thermal insulation coating.

[0037] Optionally, in the modified polyurea resin preparation step, the 80-120 parts of polyurea resin and 1-5 parts of graphene solution are mixed at a temperature of 60-90° C., at a rotation speed of 1000-2000 rpm, and for a mixing time of 1-3 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The temperature rise curves of the embodiments of the present invention and the comparative examples are shown. DETAILED DESCRIPTION

[0039] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0040] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0041] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] Although there are many non-expanding thermal insulation coatings in the prior art, the inventors have found through research that the thermal insulation performance of the current non-expanding thermal insulation coatings in the prior art cannot meet the use requirements of power batteries with high efficiency thermal insulation performance at high temperatures. In particular, polyurea coatings have low thermal conductivity, which can effectively reduce heat transfer, and also have good adhesion, which is conducive to the integrated molding of multiple battery cells in power batteries, and has high tolerance to preparation process conditions. However, the current polyurea coating is a typical expandable thermal insulation coating. Therefore, the inventors hope to provide a new type of non-expanding polyurea thermal insulation coating for use in the field of automotive batteries, which still has high efficiency thermal insulation performance at high temperatures.

[0044] In a first aspect, an embodiment of the present invention discloses a polyurea thermal insulation coating, including a component A and a component B;

[0045] Component A includes, by weight: 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 1 to 12 parts of flux, 7 to 23 parts of reflective functional filler, and 6 to 20 parts of mica powder; the modified polyurea resin is obtained by modifying polyurea resin with graphene;

[0046] Calculated by mass, component B includes: 40 to 60 parts of modified polyurea resin curing agent, 4 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 6 to 21 parts of reflective functional filler, and 6 to 25 parts of mica powder; the modified polyurea resin curing agent is obtained by modifying the polyurea resin precursor with hydroxy silicone oil.

[0047] The present invention controls the raw material composition of component A and component B in the polyurea thermal insulation coating formula, so that the polyurea resin is modified from an intumescent coating to a non-intumescent coating. However, it is not certain whether it can meet the demand for good thermal insulation performance at high temperatures in the battery field. After various attempts and experiments, the inventors determined the above technical solution.

[0048] Specifically, the ceramic filler mica powder is used to make the polyurea thermal insulation coating undergo a ceramic reaction at high temperature, thereby realizing the modification from expansion type to non-expansion type. The mica powder is one or more of phlogopite, muscovite, and synthetic mica. Preferably, the mica powder is synthetic mica, which improves the ceramic effect of the coating. The ceramic filler is formed into porcelain at high temperature, and the dense layer formed on the surface of the thermal insulation coating isolates the heat convection. The introduction of thermal insulation fillers in the A component and the B component further reduces the heat conduction. For example, the thermal insulation filler of the present invention can be a mixture of a small amount of aerogel powder and hollow glass microspheres. However, the inventor found in the experimental research process that at present, in the field of high-temperature thermal insulation coatings, although the thermal insulation route is completed by adding a large amount of thermal insulation fillers with low thermal conductivity, a typical case is achieved by adding thermal insulation fillers aerogel powder and hollow glass microspheres. The aerogel powder has a small thermal conductivity and a light specific gravity, but there is a situation where the amount added is not high. According to literature and other research, when the mass percentage of aerogel powder is added to 3%, the thickening is very serious, so the only way is to increase the amount of solvent, but the increase in the amount of solvent will lead to problems such as solidification cracking and easy cracking at high temperatures; although the thermal conductivity of hollow glass microspheres is low, they are generally spherical, and the viscosity is much lower than that of aerogel powder, but at high temperatures, their infrared heat radiation can easily penetrate the glass microspheres, causing the protected substrate to heat up rapidly and be damaged. The inventor has determined through a large number of experiments that by introducing high-reflection, high-emissivity reflective functional fillers into the formula, the coating can have a high heat reflection and external heat radiation capacity. When the coating heats up, its high emissivity can maximize the heat emission in the form of radiation, thereby delaying the rise in the coating temperature.

[0049] Among them, the modified polyurea resin is obtained by modifying the polyurea resin with graphene, so that a graphene layer is coated on the internal structure of the coating. Under combustion conditions, the graphene coating layer can be carbonized to form heat insulation, and the matched ceramic filler forms a dense ceramic layer to isolate external combustible gases, thereby having good flame retardant properties. The modified polyurea resin curing agent is obtained by modifying the polyurea resin precursor with hydroxyl silicone oil. The prior art generally modifies the polyurea resin curing agent by introducing polyols. The present invention uses hydroxyl silicone oil for modification, thereby inserting organic silicon segments, so that after the B component in the formula reacts with the A component, the Si-O bonds in the segments will be enriched on the surface. By utilizing this feature, the polyurea thermal insulation coating will first generate a layer of silicon dioxide on the surface layer at high temperature. Further, the flux in the formula will melt and solidify together with the silicon dioxide to form a dense ceramic layer, isolating external oxygen, isolating heat convection and heat conduction, and can effectively further improve the flame retardant and thermal insulation properties of the polyurea thermal insulation coating.

[0050] The present invention obtains a non-expandable polyurea thermal insulation coating suitable for the battery field and having good thermal insulation and flame retardant properties at high temperatures by combining component A and component B in the above formula and setting the content of each raw material in the specific range as described above.

[0051] In addition, the formula of the polyurea thermal insulation coating of the present invention includes component A and component B, which is convenient for separately regulating the viscosity of component A and component B during the preparation process, is beneficial to improving the curing and film-forming properties of the polyurea thermal insulation coating of the present invention, is convenient for storage, and has better processability.

[0052] Furthermore, in component A, the modified polyurea resin includes, by weight, 80 to 120 parts of polyurea resin, 1 to 5 parts of graphene solution and 0.1 to 1.2 parts of silane coupling agent; wherein the mass fraction of graphene in the graphene solution is 0.1 to 1wt%, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, propylene glycol, PEG500 polyether, and PEG1000 polyether. When graphene agglomerates, it will not be able to be evenly dispersed or coated on the structural interface during the later curing process of the coating. The silane coupling agent is used to form a small amount of chemical bonding between the dispersed graphene and the resin, reduce the agglomeration of graphene, and enhance the bonding force between the resin and graphene, so that the internal structure of the coating is coated with a tighter graphene layer, thereby improving the stability of the coating structure during use.

[0053] Furthermore, in component B, the modified polyurea resin curing agent includes, by mass, 40 to 60 parts of polyurea resin precursor, 1 to 8 parts of acetone, 40 to 60 parts of hydroxy silicone oil, 1 to 3 parts of toluene, and 1 to 3 parts of butyl ester; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%, and the hydroxyl content refers to the mass content. The present invention utilizes hydroxy silicone oil to access the organosilicon chain segment in the precursor structure, and the obtained modified polyurea resin curing agent has good stability and forms a dense ceramic layer, which can realize the ceramicization of the outer coating while the inner layer maintains the coating body state, better protects the inner coating from being decomposed and destroyed, and can play a good fireproof effect, and does not fall off or crack at high temperatures.

[0054] During the experimental research, the inventors also considered that when the inorganic filler accounts for a large proportion in the coating formula and the polyurea resin content is low, it is easy to have problems such as poor coating adhesion and surface cracking during curing. To solve the above problems, the components A and B in the polyurea thermal insulation coating formula of the present invention meet at least one of the following conditions:

[0055] The thermal insulation filler includes a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm; specifically, the thermal insulation filler is one or more of aerogel powder, sepiolite, expanded vermiculite, hollow glass microbeads, and floating beads.

[0056] The flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1 to 1:1, the particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400°C, and the melting point of flux 2 is 400 to 600°C; the above-mentioned flux is an inorganic substance with a low melting point, such as glass powder.

[0057] The reflective functional filler includes a reflective functional filler 1 and a reflective functional filler 2, the mass ratio of the reflective functional filler 1 and the reflective functional filler 2 is 0.1:1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm; specifically, the reflective functional filler is one or more of titanium dioxide, silicon carbide, boron nitride and titanium dioxide, preferably, the crystal structure of the reflective functional filler is rutile, which is beneficial to improving its reflective ability.

[0058] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size D50 of mica powder 1 is 10 to 35 μm, and the particle size D50 of mica powder 2 is 5 to 15 μm.

[0059] Specifically, when component A and component B of the present invention only meet one condition, for example, component A and component B meet the following conditions: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of thermal insulation filler 2 is 1 to 10 μm. As a result, the thermal insulation filler 2 with a small particle size is filled into the gap between the thermal insulation filler 1 with a large particle size, forming a denser thermal insulation layer. This filling action reduces air convection inside the coating, thereby reducing heat conduction. In addition, the combination of large and small particle sizes can also improve the overall uniformity of the coating, making the heat transfer path more tortuous, and effectively improving the thermal insulation effect of the coating.

[0060] When component A and component B of the present invention meet only two conditions, for example, component A and component B meet: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1-1:1, the particle size D50 of flux 1 is 15-35 μm, the particle size D50 of flux 2 is 1-8 μm, the melting point of flux 1 is 300-400°C, and the melting point of flux 2 is 400-600°C. Further addition of co-solvent 1 and co-solvent 2 helps the polyurea thermal insulation coating to form a more uniform and dense microstructure, and co-solvent 1 and co-solvent 2 have different melting points, which also ensures the stability of the coating at higher temperatures.

[0061] When component A and component B of the present invention only meet three conditions, for example, component A and component B meet: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1-1:1, flux 1 The particle size D50 of the flux 2 is 15-35 μm, the particle size D50 of the flux 2 is 1-8 μm, the melting point of the flux 1 is 300-400°C, and the melting point of the flux 2 is 400-600°C; the reflective functional filler includes a reflective functional filler 1 and a reflective functional filler 2, the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1:1-1:1, the particle size D50 of the reflective functional filler 1 is 5-25 μm, and the particle size D50 of the reflective functional filler 2 is 1-5 μm. In combination with the above, the addition of the reflective functional filler can effectively reflect thermal radiation and reduce the absorption and transfer of heat. The small-particle reflective functional filler 2 can be filled into the gaps between the large-particle reflective functional fillers 1 to form a more uniform reflective layer, further enhancing the reflection effect. Furthermore, the present invention enables shielding of heat from three paths of heat transfer, namely "heat convection, heat conduction, and heat radiation", thereby achieving a better thermal insulation effect and obtaining a polyurea thermal insulation coating with good thermal insulation performance.

[0062] When component A and component B of the present invention meet four conditions, that is, component A and component B of the present invention meet all the above conditions, component A and component B meet: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1-1:1, the particle size D50 of flux 1 is 15-35 μm, and the particle size D50 of flux 2 is 1-8 μm, the melting point of flux 1 is 300-400°C, and the melting point of flux 2 is 400-600°C; the reflective functional filler includes reflective functional filler 1 and reflective functional filler 2, the mass ratio of reflective functional filler 1 and reflective functional filler 2 is 0.1:1-1:1, the particle size D50 of reflective functional filler 1 is 5-25 μm, and the particle size D50 of reflective functional filler 2 is 1-5 μm; the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 and mica powder 2 is 1:1-3:1, the particle size D50 of mica powder 1 is 10-35 μm, and the particle size D50 of mica powder 2 is 5-15 μm.

[0063] The present invention achieves a higher densest packing structure in terms of volume of the coating by controlling the combination of different particle sizes D50 of the above-mentioned different powders, so that the coating produces the minimum volume shrinkage, deformation and cracking at high temperature, better protects the inner coating, and also has a good thermal insulation effect. In addition, by coordinating and controlling the different melting points of flux 1 and flux 2 in the formula, it is possible to match the thermal decomposition of the polyurea thermal insulation coating at high temperature, that is, when the thermal insulation coating produces partial thermal decomposition, the flux also partially melts accordingly, and fuses with the products produced by the thermal decomposition to maintain the structure of the thermal insulation coating system. When the organic components of the thermal insulation coating rapidly decompose at a higher temperature, the flux with a higher melting point also rapidly and massively melts accordingly, and fuses with the products produced by the thermal decomposition to maintain the structure of the thermal insulation coating system, maintain a dense outer isolation layer, and further enhance the thermal insulation capacity of the polyurea thermal insulation coating of the present invention.

[0064] Furthermore, in parts by mass, component A further comprises: 5 to 10 parts of anti-cracking functional additives, 0 to 1.5 parts of coupling agents and 1 to 10 parts of compounding solvents; component B further comprises: 5 to 15 parts of anti-cracking functional additives and 0 to 1.5 parts of coupling agents; the mass content of coupling agents in components A and B is different and is 0. Among them, in components A and B, the anti-cracking functional additive is a high-temperature anti-shrinkage filler, and the main components include inorganic aluminosilicate, alumina and silicon oxide. The anti-cracking functional additive of the present invention is compounded by a variety of inorganic fillers such as inorganic aluminosilicate, alumina and silicon oxide through particle size, and the fillers involved in the compounding have different volume expansion ratios at different temperatures. The volume expansion ratio can be automatically adjusted according to the temperature of the polyurea thermal insulation coating in the later fireproof and heat insulation process, preventing the polyurea thermal insulation coating itself from cracking due to volume collapse caused by ablation of organic components or melting of flux, thereby retaining the dense structure of the coating, minimizing the damage of thermal convection and thermal radiation to the substrate protected by the coating, and further improving the problem of surface cracking of the coating at high temperature. In addition, a compound solvent is further added to component A, wherein the compound solvent includes toluene, acetone and butyl ester, and the mass ratio of toluene, acetone and butyl ester is (0-1): (1-3): (0-1), which can improve the dispersibility of the powder, and compound the solvent so that the coating volatilizes gradually during the film forming process, thereby making the entire curing process more moderate, and the film-forming surface is more delicate, smooth and flat, further improving the problem of surface film cracking during the curing process. By adding a coupling agent to component A and component B, the coupling agent can couple the powder and the polyurea resin in the formula, so that the organic-inorganic two phases form chemical bonds and cross-link, further improving the problem of surface film cracking during the curing process.

[0065] In the polyurea thermal insulation coatings of the above embodiments, it is precisely because of the mutual coordination of different powders in the above embodiments and the addition of a large amount of low-density thermal insulation fillers, for example, the density of the thermal insulation filler is 0.3g / cm 3 The density of the polyurea thermal insulation coating of the present invention is less than 1.0 g / cm 3 , which is beneficial to increase the porosity in the dense ceramic layer, which can effectively isolate heat transfer, thereby further improving the thermal insulation effect of the coating. In addition to the foaming type of thermal insulation coating on the market, the density is 1.0g / cm 3 above.

[0066] In a second aspect, the present invention provides a method for preparing a polyurea thermal insulation coating, which is used to prepare the polyurea thermal insulation coating of each of the above embodiments, comprising the following steps:

[0067] Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 7 to 23 parts of reflective functional filler and 6 to 20 parts of mica powder are mixed to obtain component A; the modified polyurea resin is obtained by modifying polyurea resin with graphene;

[0068] Preparation of component B: by weight, 40 to 60 parts of modified polyurea resin curing agent, 4 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 6 to 21 parts of reflective functional filler and 6 to 25 parts of mica powder are mixed to obtain component B; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor with hydroxy silicone oil;

[0069] Preparation of polyurea thermal insulation coating: Component A and component B are mixed and cured to obtain polyurea thermal insulation coating.

[0070] The present invention improves the simplicity of the process by separately controlling the preparation steps of component A and component B in the formula, thereby ensuring the adaptive combination of component A and component B. Through the above steps, the preparation process is simple and efficient, and it is convenient to prepare a polyurea thermal insulation coating that has both high temperature resistance and thermal insulation performance and good flame retardancy.

[0071] In the preparation method of the polyurea thermal insulation coating of the present invention, at least one of the following conditions is satisfied in the steps of preparing component A and component B:

[0072] The thermal insulation filler includes a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm;

[0073] The flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1-1:1, the particle size D50 of flux 1 is 15-35 μm, the particle size D50 of flux 2 is 1-8 μm, the melting point of flux 1 is 300-400° C., and the melting point of flux 2 is 400-600° C.;

[0074] The reflective functional filler comprises a reflective functional filler 1 and a reflective functional filler 2, wherein the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm;

[0075] The mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size D50 of mica powder 1 is 10 to 35 μm, and the particle size D50 of mica powder 2 is 5 to 15 μm.

[0076] Specifically, when the preparation steps of component A and component B meet only one condition, for example, the preparation steps of component A and component B meet: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 and thermal insulation filler 2 is 0.8:1~1.5:1, the particle size D50 of thermal insulation filler 1 is 20~50μm, and the particle size D50 of thermal insulation filler 2 is 1~10μm.

[0077] When the steps of preparing component A and component B of the present invention satisfy only two conditions, for example, the steps of preparing component A and component B satisfy: the thermal insulation filler comprises thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux comprises flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1-1:1, the particle size D50 of flux 1 is 15-35 μm, the particle size D50 of flux 2 is 1-8 μm, the melting point of flux 1 is 300-400°C, and the melting point of flux 2 is 400-600°C.

[0078] When the steps of preparing component A and component B of the present invention only meet three conditions, for example, the steps of preparing component A and component B meet the following conditions: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1-1: 1. The particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400°C, and the melting point of flux 2 is 400 to 600°C; the reflective functional filler includes reflective functional filler 1 and reflective functional filler 2, the mass ratio of reflective functional filler 1 to reflective functional filler 2 is 0.1 to 1:1, the particle size D50 of reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of reflective functional filler 2 is 1 to 5 μm.

[0079] When the preparation steps of component A and component B of the present invention meet four conditions, that is, the preparation steps of component A and component B of the present invention meet all the above conditions, the preparation steps of component A and component B meet: the thermal insulation filler includes thermal insulation filler 1 and thermal insulation filler 2, the mass ratio of thermal insulation filler 1 to thermal insulation filler 2 is 0.8:1-1.5:1, the particle size D50 of thermal insulation filler 1 is 20-50 μm, and the particle size D50 of thermal insulation filler 2 is 1-10 μm; the flux includes flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1-1:1, the particle size D50 of flux 1 is 15-35 μm, and the particle size D50 of flux 2 is 15-25 μm. The particle size D50 is 1 to 8 μm, the melting point of flux 1 is 300 to 400°C, and the melting point of flux 2 is 400 to 600°C; the reflective functional filler includes reflective functional filler 1 and reflective functional filler 2, the mass ratio of reflective functional filler 1 to reflective functional filler 2 is 0.1 to 1:1, the particle size D50 of reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of reflective functional filler 2 is 1 to 5 μm; the mica powder includes mica powder 1 and mica powder 2, the mass ratio of mica powder 1 to mica powder 2 is 1:1 to 3:1, the particle size D50 of mica powder 1 is 10 to 35 μm, and the particle size D50 of mica powder 2 is 5 to 15 μm.

[0080] The preparation method of the present invention obtains a polyurea thermal insulation coating with a dense stacking structure by controlling the different particle sizes of different powders and the different melting points of fluxes with different particle sizes in the preparation steps of component A and component B in the formula, and enables the polyurea thermal insulation coating to have good thermal insulation ability and improves the problem of surface cracking of the coating at high temperatures.

[0081] Furthermore, the preparation method of the polyurea thermal insulation coating of the present invention comprises the following steps:

[0082] Preparation of modified polyurea resin: 80-120 parts of polyurea resin and 1-5 parts of graphene solution are mixed by weight, and 0.1-1.2 parts of silane coupling agent are added to mix to obtain modified polyurea resin; wherein the mass fraction of graphene in the graphene solution is 0.1-1wt%, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, glycerol, PEG500 polyether, PEG1000 polyether. Thus, the graphene is well dispersed in the resin system.

[0083] Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin and 5 to 10 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 2 to 8 parts of reflective functional filler 1 and 5 to 15 parts of reflective functional filler 2 are added in sequence and mixed, and then 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 10 parts of mica powder 2 are added and mixed, and after cooling to room temperature, 1 to 10 parts of compounding solvent are mixed to obtain component A; wherein mixing the powder at a temperature of 90 to 100° C. is beneficial to reducing the viscosity of the powder and improving the dispersibility of the powder.

[0084] Preparation of modified polyurea resin curing agent: by weight, at a temperature of 60 to 90° C., 40 to 60 parts of polyurea resin precursor, 17 to 29 parts of acetone and 40 to 60 parts of hydroxy silicone oil are mixed, and after heat preservation for 3 to 5 hours, 16 to 21 parts of acetone are evaporated, and 1 to 3 parts of toluene and 1 to 3 parts of butyl ester are added and mixed to obtain a modified polyurea resin curing agent; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%.

[0085] Preparation of component B: by weight, 40 to 60 parts of modified polyurea resin curing agent and 5 to 15 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 1 to 6 parts of reflective functional filler 1, 5 to 15 parts of reflective functional filler 2, 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 15 parts of mica powder 2 are added in sequence, and the mixture is cooled to room temperature to obtain component B; wherein mixing the powder at a temperature of 90 to 100° C. is beneficial to reducing the viscosity of the powder and improving the dispersibility of the powder.

[0086] Preparation of polyurea thermal insulation coating: Component A and component B are mixed and then cured on the surface of a template to obtain a polyurea thermal insulation coating.

[0087] The preparation method of the present invention obtains a polyurea thermal insulation coating having both high temperature resistance and thermal insulation properties through the mutual cooperation of the above steps, and has good flame retardant properties, and can be used in the battery field.

[0088] The inventors also found that the introduction of graphene in the conventional formula is by directly adding graphene stock solution or graphene solution to the resin and simply stirring. The above-mentioned dispersion method will cause the graphene itself to agglomerate during the dispersion process, and it cannot be evenly dispersed or coated with the structural interface during the later curing process, so that the mechanical properties and flame retardant properties of the coating cannot reach the ideal state. The inventors have found through experimental research that the above problems can be solved by heating the polyurea resin, reducing the viscosity of the raw materials in the formula, and then high-speed shear dispersion. In this way, the graphene is evenly dispersed in components A and B, and the agglomeration of graphene is reduced. At the same time, by adding a silane coupling agent, a small amount of chemical bonding is formed between the dispersed graphene and the polyurea resin, which further reduces agglomeration and increases the bonding force of the two phases. Specifically, in the preparation step of the modified polyurea resin, the temperature of mixing 80 to 120 parts of polyurea resin and 1 to 5 parts of graphene solution is 60 to 90°C, and the mixing is carried out at a speed of 1000 to 2000 rpm, and the mixing time is 1 to 3 hours.

[0089] The preparation method of the polyurea thermal insulation coating of the present invention will be described in further detail below.

[0090] Example 1 is a polyurea thermal insulation coating, and its specific preparation method is as follows:

[0091] a. Preparation of modified polyurea resin

[0092] By weight, 100 parts of polyurea resin and 3 parts of graphene solution are mixed and dispersed at 80° C. and 1500 rpm for 2 hours, and then 0.8 parts of silane coupling agent are added and mixed. The mixture is kept warm for 30 minutes, vacuumed and cooled to room temperature to obtain a modified polyurea resin. The mass fraction of graphene in the graphene solution is 0.5wt%, and the solvent in the graphene solution is diethylene glycol.

[0093] bA component preparation

[0094] By mass, 42.7 parts of modified polyurea resin and 8.5 parts of anti-cracking functional additive were stirred and mixed at a speed of 800 rpm for 10 min, and then 5.1 parts of D50 = 35 μm thermal insulation filler 1 were added and stirred and mixed at a speed of 800 rpm for 10 min, and then 5.1 parts of D50 = 5 μm thermal insulation filler 2 were added and stirred and mixed at a water bath temperature of 90-100 ° C and a speed of 800 rpm for 10 min, and 1.7 parts of D50 = 25 μm flux 1 were added and stirred and mixed at a speed of 800 rpm for 10 min, 2.6 parts of D50 = 3 μm flux 2 were added and stirred and mixed at a speed of 800 rpm for 10 min, and 4.3 parts of D50 = 25 μm flux 1 were added and stirred and mixed at a speed of 800 rpm for 10 min. =15μm reflective functional filler 1 is stirred and mixed at a speed of 1200rmp / min for 10min and 8.5 parts of reflective functional filler 2 with D50=2μm is stirred and mixed at a speed of 1200rmp / min for 10min, then 8.5 parts of mica powder 1 with D50=25μm is stirred and mixed at a speed of 1200rmp / min for 10min and 4.3 parts of mica powder 2 with D50=12μm are stirred and mixed at a speed of 1200rmp / min for 10min, after cooling to room temperature, and 8.5 parts of compound solvent are stirred and mixed at a speed of 500rmp / min for 20min to obtain component A; wherein the compound solvent is toluene, acetone and butyl ester, and the mass ratio of toluene, acetone and butyl ester is 1:3:1.

[0095] c. Preparation of modified polyurea resin curing agent

[0096] By weight, at a temperature of 80°C, 50 parts of a polyurea resin precursor and 25 parts of acetone are dropwise added with 50 parts of hydroxy silicone oil (with a hydroxyl content of 8.18%) within 2 hours, and the mixture is kept warm for 4 hours, condensed and refluxed, and then rotary evaporated until 19 parts of acetone are evaporated, and 2 parts of toluene and 2 parts of butyl ester are added and stirred for 15 minutes to obtain a modified polyurea resin curing agent; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate.

[0097] dB component preparation

[0098] By mass, 46.5 parts of modified polyurea resin curing agent and 9.3 parts of anti-cracking functional additive were stirred and mixed at a speed of 800 rpm for 10 minutes, and then 5.6 parts of D50 = 35 μm thermal insulation filler 1 were added and stirred and mixed at a speed of 800 rpm for 10 minutes, and then 5.6 parts of D50 = 5 μm thermal insulation filler 2 were added and stirred and mixed at a water bath temperature of 90-100 ° C and a speed of 800 rpm for 10 minutes, and 1.9 parts of D50 = 25 μm flux 1 were added in sequence and stirred and mixed at a speed of 800 rpm for 10 minutes. 4.6 parts of D50=15μm reflective functional filler 1 were stirred and mixed at a speed of 1200rmp / min for 10min, 9.3 parts of D50=2μm reflective functional filler 2 were stirred and mixed at a speed of 1200rmp / min for 10min, 0.6 parts of coupling agent KH780, 9.3 parts of D50=25μm mica powder 1 and 4.6 parts of D50=12μm mica powder 2 were stirred and mixed at a speed of 1200rmp / min for 10min, and then cooled to room temperature to obtain component B.

[0099] e. Preparation of polyurea thermal insulation coating:

[0100] Weigh 30-50g of component A and 30-50g of component B, and the mass ratio of component A to component B is 100:100, and stir and mix at a speed of 2000 rpm for 1 minute. Apply the mixed component A and component B on a 1mm thick aluminum plate by scraping or spraying, and dry at room temperature for 24 hours or at 60°C for 4 hours until it is completely cured to obtain the polyurea thermal insulation coating of Example 1.

[0101] The formula of the polyurea thermal insulation coating of Example 1 is shown in Table 1.

[0102] Table 1. Formulation of polyurea thermal insulation coating of Example 1

[0103] raw material Component A Component B Modified polyurea resin 42.7 0 Modified polyurea resin curing agent 0 46.5 Anti-cracking functional additives 8.5 9.3 Thermal insulation filler 1 (hollow glass beads-50um) 5.1 5.6 Thermal insulation filler 2 (hollow glass beads-10um) 5.1 5.6 Flux 1 (glass powder -380℃) 1.7 1.9 Flux 2 (glass powder -500℃) 2.6 2.8 Reflective functional filler 1 (rutile titanium dioxide 15um) 4.3 4.6 Reflective functional filler 2 (rutile titanium dioxide 2um) 8.5 9.3 Mica powder 1(25um) 8.5 9.3 Mica powder 2(12um) 4.3 4.6 Coupling agent (KH870) 0 0.6 Compound solvent 8.5 0

[0104] Example 2

[0105] The difference between Example 2 and Example 1 is that in the formula of Example 2, component A does not contain an anti-cracking functional additive, component B does not contain an anti-cracking functional additive, and the mass ratio of component A to component B is 91.3:90.8. The formula of Example 2 is shown in Table 2.

[0106] Table 2. Formulation of polyurea thermal insulation coating of Example 2

[0107] raw material Component A Component B Modified polyurea resin 42.7 0 Modified polyurea resin curing agent 0 46.5 Anti-cracking functional additives 0 0 Thermal insulation filler 1 (hollow glass beads-50um) 5.1 5.6 Thermal insulation filler 2 (hollow glass beads-10um) 5.1 5.6 Flux 1 (glass powder -380℃) 1.7 1.9 Flux 2 (glass powder -500℃) 2.6 2.8 Reflective functional filler 1 (rutile titanium dioxide 15um) 4.3 4.6 Reflective functional filler 2 (rutile titanium dioxide 2um) 8.5 9.3 Mica powder 1(25um) 8.5 9.3 Mica powder 2(12um) 4.3 4.6 Coupling agent (KH870) 0 0.6 Compound solvent 8.5 0

[0108] Example 3

[0109] The difference between Example 3 and Example 1 is that in the formula of Example 3, component A does not contain flux 2, and the amount of flux 1 added is the sum of the amounts of flux 1 and flux 2 added in component A in Example 1; component B does not contain flux 2, and the amount of flux 1 added is the sum of the amounts of flux 1 and flux 2 added in component B in Example 1. The formula of Example 3 is shown in Table 3.

[0110] Table 3. Formulation of polyurea thermal insulation coating of Example 3

[0111] raw material Component A Component B Modified polyurea resin 42.7 0 Modified polyurea resin curing agent 0 46.5 Anti-cracking functional additives 8.5 9.3 Thermal insulation filler 1 (hollow glass beads-50um) 5.1 5.6 Thermal insulation filler 2 (hollow glass beads-10um) 5.1 5.6 Flux 1 (glass powder -380℃) 4.3 4.7 Flux 2 (glass powder -500℃) 0 0 Reflective functional filler 1 (rutile titanium dioxide 15um) 4.3 4.6 Reflective functional filler 2 (rutile titanium dioxide 2um) 8.5 9.3 Mica powder 1(25um) 8.5 9.3 Mica powder 2(12um) 4.3 4.6 Coupling agent (KH870) 0 0.6 Compound solvent 8.5 0

[0112] Example 4

[0113] The difference between Example 4 and Example 1 is that in the formula of Example 4, component A does not contain thermal insulation filler 2, and the amount of thermal insulation filler 1 added is the sum of the amounts of thermal insulation filler 1 and thermal insulation filler 2 added in component A in Example 1; component B does not contain thermal insulation filler 2, and the amount of thermal insulation filler 1 added is the sum of the amounts of thermal insulation filler 1 and thermal insulation filler 2 added in component B in Example 1. The formula of Example 4 is shown in Table 4.

[0114] Table 4. Formulation of polyurea thermal insulation coating of Example 4

[0115] raw material Component A Component B Modified polyurea resin 42.7 0 Modified polyurea resin curing agent 0 46.5 Anti-cracking functional additives 8.5 9.3 Thermal insulation filler 1 (hollow glass beads-50um) 10.2 11.2 Thermal insulation filler 2 (hollow glass beads-10um) 0 0 Flux 1 (glass powder -380℃) 1.7 1.9 Flux 2 (glass powder -500℃) 2.6 2.8 Reflective functional filler 1 (rutile titanium dioxide 15um) 4.3 4.6 Reflective functional filler 2 (rutile titanium dioxide 2um) 8.5 9.3 Mica powder 1(25um) 8.5 9.3 Mica powder 2(12um) 4.3 4.6 Coupling agent (KH870) 0 0.6 Compound solvent 8.5 0

[0116] Comparative Example 1

[0117] The difference between Comparative Example 1 and Example 1 is that the polyurea resin in component A of the formula of Comparative Example 1 is not modified by the graphene solution, and the other parts are consistent with Example 1. The formula of Comparative Example 1 is shown in Table 5.

[0118] Table 5. Formula of polyurea thermal insulation coating of comparative example 1

[0119] raw material Component A Component B Unmodified polyurea resin 42.7 0 Modified polyurea resin curing agent 0 46.5 Anti-cracking functional additives 8.5 9.3 Thermal insulation filler 1 (hollow glass beads-50um) 5.1 5.6 Thermal insulation filler 2 (hollow glass beads-10um) 5.1 5.6 Flux 1 (glass powder -380℃) 1.7 1.9 Flux 2 (glass powder -500℃) 2.6 2.8 Reflective functional filler 1 (rutile titanium dioxide 15um) 4.3 4.6 Reflective functional filler 2 (rutile titanium dioxide 2um) 8.5 9.3 Mica powder 1(25um) 8.5 9.3 Mica powder 2(12um) 4.3 4.6 Coupling agent (KH870) 0 0.6 Compound solvent 8.5 0

[0120] Comparative Example 2

[0121] Purchase commercially available water-based epoxy steel structure fire retardant coating.

[0122] Comparative Example 3

[0123] Purchase commercially available water-based acrylic steel structure fire retardant coating.

[0124] The shear strength, density, thermal conductivity, volume shrinkage, porcelain formation, temperature difference between the cold surface and the hot surface, and temperature rise curve of different embodiments and comparative examples were tested. The specific test methods and test standards of different test items are shown in Table 6. The test results are shown in Table 7.

[0125] Table 6. Test methods and test standards for different test items

[0126]

[0127] Table 7. Measurement results of examples and comparative examples

[0128]

[0129] From Table 7, we can see that the specific results are as follows:

[0130] The density of the polyurea thermal insulation coating of Examples 1-4 of the present invention is less than 1.0 g / cm 3 Compared with Example 2, Example 3, and Example 4, Example 1 has the lowest density and thermal conductivity. This is because the proportion of hollow glass beads in Example 1 is relatively large, and the density of hollow glass beads is very small, and the thermal conductivity is very low, so Example 1 has the lowest density of 0.73g / cm 3 , the thermal conductivity is also very low, only 0.073W / m·K.

[0131] Compared with Example 2, Example 3, and Example 4, Example 1 has a relatively high shear strength of 2.45 MPa on the aluminum plate, while Example 2 does not have an anti-cracking functional additive in the formula, so the amount of powder added is less than that of Example 1, so the shear strength is slightly greater than that of Example 1; the shear strengths of Example 3 and Example 4 are relatively close to that of Example 1, because Example 1 further meets more conditions for the size of the particle size, and is closer to dense packing in space, so that the coating and the aluminum plate are in full contact, so it is slightly higher than that of Example 3 and Example 4. Example 1 has the lowest dimensional shrinkage at 600°C, followed by Example 4 and Example 3. This is because compared with Example 2, Example 1, Example 3, and Example 4 have an anti-cracking functional additive in the formula, and the anti-cracking functional additive will undergo a slight volume expansion at high temperature and combine with other components to form a continuous dense layer, that is, it plays an anti-cracking role, and also helps to maintain the structural strength of the product.

[0132] In addition, because Example 1 also has an anti-cracking functional additive in the formula and a particle size that meets more conditions, compared with Examples 2-4, Example 1 has a larger temperature difference between the cold surface and the hot surface, and at the same time, no cracking occurs, and the thermal insulation performance is better.

[0133] The difference between Comparative Example 1 and Example 1 is that the polyurea resin of component A in Comparative Example 1 is not modified with graphene, and the coupling agent in the graphene modification forms a chemical bond crosslink between the graphene and the resin, thereby enhancing the overall mechanical strength. On the other hand, graphene improves the flame retardant effect of the resin, thereby increasing the difficulty of thermal decomposition of the coating at high temperature, reducing the amount of ablation, and reducing the thermal decomposition rate. The release of combustion heat is more gradual, and the temperature rise caused by the heat release of the system due to its own combustion is lower. Therefore, the thermal insulation effect of Example 1 in the temperature rise test on a 600°C hot stage is slightly better than that of Comparative Example 1.

[0134] Although Comparative Examples 2 and 3 also have certain heat insulation and fire prevention effects, because they are intumescent fire retardant coatings, when heated at high temperatures, the system undergoes carbonization expansion. Example 1 expands from a 1mm thickness to a carbon layer of about 35mm, and the expansion ratio of Example 2 is lower than that of Example 1, expanding to about 10mm. Both can well isolate the transfer of heat. In many cases, there is no volume expansion space. For example, between the cells of new energy lithium-ion power batteries, the gap between the cells is generally only 1-3mm. The intumescent fire retardant coating has no expansion space at high temperatures, so it cannot play a role in heat insulation and fire prevention. Another very fatal problem is that the carbon layer formed at high temperatures can easily cause the arcing effect of the cell, which will break through the metal shell of the cell, and even directly break through the upper cover of the Pack, thereby causing more intense thermal runaway. Therefore, the application of intumescent fire retardant coatings in power batteries is very limited in heat insulation and fire prevention, and it cannot be used between cells.

[0135] like Figure 1 As shown, the blank aluminum plate is used as the blank control group. The polyurea thermal insulation coatings of Examples 1-4 of the present invention all have thermal insulation and fireproofing effects, among which Example 1 has the highest effect. At a temperature of 600°C, a coating with a thickness of 1 mm can isolate most of the heat and reduce the temperature of the cold surface to about 218°C. Example 4 is second, reducing the temperature of the cold surface to about 278.5°C.

[0136] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A polyurea thermal insulation coating, characterized in that: It includes component A and component B; The component A comprises, by weight: 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 1 to 12 parts of flux, 7 to 23 parts of reflective functional filler, and 6 to 20 parts of mica powder; the modified polyurea resin is obtained by modifying polyurea resin with graphene; In parts by mass, the B component includes: 40 to 60 parts of modified polyurea resin curing agent, 4 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 6 to 21 parts of reflective functional filler, and 6 to 25 parts of mica powder; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor with hydroxy silicone oil.

2. The polyurea thermal insulation coating according to claim 1, characterized in that: In the component A, the modified polyurea resin includes, by mass, 80 to 120 parts of polyurea resin, 1 to 5 parts of graphene solution and 0.1 to 1.2 parts of silane coupling agent; wherein the mass fraction of graphene in the graphene solution is 0.1 to 1 wt %, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, glycerol, PEG500 polyether and PEG1000 polyether.

3. The polyurea thermal insulation coating according to claim 1, characterized in that: In the B component, the modified polyurea resin curing agent includes, by mass, 40 to 60 parts of a polyurea resin precursor, 1 to 8 parts of acetone, 40 to 60 parts of hydroxy silicone oil, 1 to 3 parts of toluene, and 1 to 3 parts of butyl ester; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%.

4. The polyurea thermal insulation coating according to claim 1, characterized in that: The A component and the B component satisfy at least one of the following conditions: The thermal insulation filler comprises a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm; The flux comprises flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1 to 1:1, the particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400° C., and the melting point of flux 2 is 400 to 600° C.; The reflective functional filler comprises a reflective functional filler 1 and a reflective functional filler 2, wherein the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1:1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm; The mica powder includes mica powder 1 and mica powder 2, the mass ratio of the mica powder 1 to the mica powder 2 is 1:1 to 3:1, the particle size D50 of the mica powder 1 is 10 to 35 μm, and the particle size D50 of the mica powder 2 is 5 to 15 μm.

5. The polyurea thermal insulation coating according to claim 4, characterized in that: In parts by mass, the component A further comprises: 5 to 10 parts of an anti-cracking functional additive, 0 to 1.5 parts of a coupling agent and 1 to 10 parts of a compound solvent; the component B further comprises: 5 to 15 parts of an anti-cracking functional additive and 0 to 1.5 parts of a coupling agent; the coupling agent mass content of the component A and the component B is not 0 at the same time.

6. The polyurea thermal insulation coating according to any one of claims 1 to 5, characterized in that: The density of the polyurea thermal insulation coating is less than 1.0 g / cm 3 .

7. A method for preparing the polyurea thermal insulation coating according to any one of claims 1 to 5, comprising the following steps: Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin, 6 to 14 parts of thermal insulation filler, 2 to 12 parts of flux, 7 to 23 parts of reflective functional filler and 6 to 20 parts of mica powder are mixed to obtain component A; the modified polyurea resin is obtained by modifying polyurea resin with graphene; Preparation of component B: by weight, 40 to 60 parts of a modified polyurea resin curing agent, 4 to 14 parts of a heat insulating filler, 2 to 12 parts of a flux, 6 to 21 parts of a reflective functional filler and 6 to 25 parts of mica powder are mixed to obtain component B; the modified polyurea resin curing agent is obtained by modifying a polyurea resin precursor with hydroxy silicone oil; Preparation of polyurea thermal insulation coating: Component A and component B are mixed and cured to obtain polyurea thermal insulation coating.

8. The method for preparing the polyurea thermal insulation coating according to claim 7, wherein the steps of preparing component A and component B satisfy at least one of the following conditions: The thermal insulation filler comprises a thermal insulation filler 1 and a thermal insulation filler 2, the mass ratio of the thermal insulation filler 1 to the thermal insulation filler 2 is 0.8:1 to 1.5:1, the particle size D50 of the thermal insulation filler 1 is 20 to 50 μm, and the particle size D50 of the thermal insulation filler 2 is 1 to 10 μm; The flux comprises flux 1 and flux 2, the mass ratio of flux 1 to flux 2 is 0.1:1 to 1:1, the particle size D50 of flux 1 is 15 to 35 μm, the particle size D50 of flux 2 is 1 to 8 μm, the melting point of flux 1 is 300 to 400° C., and the melting point of flux 2 is 400 to 600° C.; The reflective functional filler comprises a reflective functional filler 1 and a reflective functional filler 2, wherein the mass ratio of the reflective functional filler 1 to the reflective functional filler 2 is 0.1:1 to 1:1, the particle size D50 of the reflective functional filler 1 is 5 to 25 μm, and the particle size D50 of the reflective functional filler 2 is 1 to 5 μm; The mica powder includes mica powder 1 and mica powder 2, the mass ratio of the mica powder 1 to the mica powder 2 is 1:1 to 3:1, the particle size D50 of the mica powder 1 is 10 to 35 μm, and the particle size D50 of the mica powder 2 is 5 to 15 μm.

9. The method for preparing the polyurea thermal insulation coating according to claim 8, comprising the following steps: Preparation of modified polyurea resin: After mixing 80-120 parts of polyurea resin and 1-5 parts of graphene solution by weight, 0.1-1.2 parts of silane coupling agent are added and mixed to obtain modified polyurea resin; wherein the mass fraction of graphene in the graphene solution is 0.1-1wt%, and the solvent in the graphene solution is one or more of water, acetone, xylene, butyl ester, diethylene glycol, glycerol, PEG500 polyether and PEG1000 polyether; Preparation of component A: by weight, 40 to 60 parts of modified polyurea resin and 5 to 10 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 2 to 8 parts of reflective functional filler 1 and 5 to 15 parts of reflective functional filler 2 are added in sequence and mixed, and then 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 10 parts of mica powder 2 are added and mixed, and after cooling to room temperature, 1 to 10 parts of compounding solvent are mixed to obtain component A; Preparation of modified polyurea resin curing agent: by weight, at a temperature of 60 to 90° C., 40 to 60 parts of polyurea resin precursor, 17 to 29 parts of acetone and 40 to 60 parts of hydroxy silicone oil are mixed, and after heat preservation for 3 to 5 hours, 16 to 21 parts of acetone are evaporated, and 1 to 3 parts of toluene and 1 to 3 parts of butyl ester are added and mixed to obtain a modified polyurea resin curing agent; the polyurea resin precursor is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene-1,6-diisocyanate; the hydroxyl content of the hydroxy silicone oil is 6 to 10%; Preparation of component B: by weight, 40 to 60 parts of modified polyurea resin curing agent and 5 to 15 parts of anti-cracking functional additive are mixed, 3 to 7 parts of thermal insulation filler 1 are added and mixed, and then 3 to 7 parts of thermal insulation filler 2 are added and mixed at a temperature of 90 to 100° C., 1 to 6 parts of flux 1, 1 to 6 parts of flux 2, 1 to 6 parts of reflective functional filler 1, 5 to 15 parts of reflective functional filler 2, 0 to 1.5 parts of coupling agent, 5 to 10 parts of mica powder 1 and 1 to 15 parts of mica powder 2 are added in sequence and mixed, and after cooling to room temperature, component B is obtained; Preparation of polyurea thermal insulation coating: Component A and component B are mixed and then cured on the surface of a template to obtain a polyurea thermal insulation coating.

10. The method for preparing a polyurea thermal insulation coating according to claim 9, wherein in the modified polyurea resin preparation step, the 80 to 120 parts of polyurea resin and 1 to 5 parts of graphene solution are mixed at a temperature of 60 to 90°C, at a rotation speed of 1000 to 2000 rpm, and for a mixing time of 1 to 3 hours.

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