A kind of heat-insulating acrylic emulsion and its preparation method and application

Abstract

The present invention discloses a thermal insulation acrylic emulsion, its preparation method, and application. The thermal insulation acrylic emulsion comprises hollow microspheres and is prepared from the following raw materials: an emulsifier 1, an unsaturated acid 1, an olefin monomer 1, an initiator 1, a seed emulsion, and water; the seed emulsion is prepared from the following raw materials: an emulsifier 2, an unsaturated acid 2, an olefin monomer 2, an initiator 2, a siloxane compound with an active group, and water. The thermal insulation acrylic emulsion of the present invention has a high sphericity, is free of breakage, and has a good core-shell structure, thus exhibiting excellent thermal insulation properties. The raw materials used in preparing the thermal insulation acrylic emulsion include a siloxane compound with an active group, which can improve the stability of the hollow microspheres during the synthesis process, solve the problem of hollow microspheres rupturing during expansion, and improve the thermal insulation performance of the thermal insulation acrylic emulsion, thereby imparting high reflective insulation efficiency to the thermal insulation coating.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer functional materials, and in particular to a heat-insulating acrylic emulsion and a preparation method and application thereof. Background Art

[0002] In cities with highly concentrated functions and heavy reliance on electricity and fossil fuels, improper energy utilization generates various types of waste heat. Combined with the urban heat island effect, improving insulation systems is crucial for efficient energy utilization. Therefore, improving the insulation of living spaces is a key approach to improving energy efficiency and enhancing building comfort and functionality. The selection of insulation materials, the layout of the insulation system, and the design of the insulation system all play a key role in achieving thermal insulation. Among various insulation materials, insulation panels and coatings are gaining popularity among businesses and the public for their ease of application, high thermal insulation performance, affordability, and thermal stability. Currently, the thermal insulation coatings on the market primarily include barrier, reflective, and radiant coatings. Barrier coatings typically incorporate inorganic heat-shielding materials. These materials emit high-energy electromagnetic waves, forming a heat-shielding layer on the coating surface, blocking heat. Reflective coatings typically incorporate highly reflective materials to achieve a high degree of reflection of sunlight. Radiation-type thermal insulation coatings usually add high-radiation materials to the thermal insulation coatings to radiate the residual heat on the surface of the object into the atmosphere, thereby reducing the surface temperature of the object.

[0003] Traditional insulation materials include expanded perlite products, aerated concrete, foamed concrete, polystyrene foam, polyurethane foam, and nanoporous silica aerogel. However, these materials suffer from high prices, poor tensile strength, cracking when thickly applied, poor stain resistance, and poor flexibility, which compromise the insulation effectiveness of subsequent coatings. Therefore, developing an insulation material with superior thermal insulation performance is of paramount importance. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the purposes of the present invention is to provide a thermal insulation acrylic emulsion. A second purpose of the present invention is to provide a method for preparing the above-mentioned thermal insulation acrylic emulsion. A third purpose of the present invention is to provide the application of the above-mentioned thermal insulation acrylic emulsion in thermal insulation materials. A fourth purpose of the present invention is to provide a thermal insulation coating. A fifth purpose of the present invention is to provide the application of the above-mentioned thermal insulation coating in building walls.

[0005] During the preparation of hollow microspheres, a significant negative pressure is generated during their neutralization and expansion. If the latex particles are not stable enough, they can easily break, resulting in insufficient microsphere expansion or breakage, which in turn affects the thermal insulation performance of the hollow microspheres. In the present invention, a siloxane compound with an active group is added to the seed emulsion, primarily acting as a scaffold for the hollow microspheres and improving their stability during the synthesis process.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A first aspect of the present invention provides a thermal insulation acrylic emulsion, wherein the latex particles in the thermal insulation acrylic emulsion are hollow microspheres, and the thermal insulation acrylic emulsion comprises the following raw materials in parts by weight: 0.1 to 1 parts of an emulsifier, 0.05 to 0.3 parts of an unsaturated acid, 20 to 27 parts of an olefin monomer, 0.05 to 0.5 parts of an initiator, 7 to 25 parts of a seed emulsion, and 50 to 80 parts of water;

[0008] The seed emulsion comprises the following raw materials in parts by mass: 0.5-3 parts of emulsifier, 5-20 parts of unsaturated acid, 0.05-0.2 parts of olefin monomer, 0.05-1 part of initiator, 2.5-10 parts of silicone compound with active group, and 50-80 parts of water.

[0009] Preferably, the thermal insulation acrylic emulsion is prepared from the following raw materials in parts by mass: 0.1-1 parts of emulsifier, 0.05-1 parts of unsaturated acid, 20-25 parts of olefin monomer, 1-3 parts of initiator, 12-23 parts of seed emulsion, and 60-75 parts of water.

[0010] Preferably, the seed emulsion is prepared from the following raw materials in parts by weight: 0.5-2 parts of an emulsifier, 10-15 parts of an unsaturated acid, 20-25 parts of an olefin monomer, 0.05-1 part of an initiator, 6-10 parts of a siloxane compound with an active group, and 50-70 parts of water. More preferably, the siloxane compound with an active group is in an amount of 6, 7, 8, 9, or 10 parts by weight.

[0011] Preferably, the emulsifier is selected from at least one of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, fatty alcohol polyoxyethylene ether, polyoxyethylene alkyl ester, and sodium cetyl betaine.

[0012] Preferably, the unsaturated acid is selected from at least one of acrylic acid, methacrylic acid, itaconic acid and fumaric acid.

[0013] Preferably, the olefin monomer is selected from at least one of styrene, methyl methacrylate, butyl acrylate, acrylonitrile and isooctyl acrylate.

[0014] Preferably, the initiator is selected from at least one of sodium persulfate, ammonium persulfate and potassium persulfate.

[0015] Preferably, the raw materials of the heat-insulating acrylic emulsion further include 0.0.1 to 0.2 parts of a post-treatment agent; the post-treatment agent includes tert-butyl hydroperoxide and ascorbic acid.

[0016] Preferably, the raw materials of the heat-insulating acrylic emulsion further include 0.5 to 2 parts of a pH regulator. More preferably, the pH regulator is aqueous ammonia.

[0017] Preferably, the siloxane compound with active groups is prepared by a preparation method comprising the following steps: methacryloxypropyl alkoxysilane reacts with alkyl silicate to prepare the siloxane compound with active groups.

[0018] More preferably, the methacryloxypropyl alkoxysilane is at least one selected from γ-methacryloxypropyl trimethoxysilane, γ-methacryloxypropyl triethoxysilane or γ-methacryloxypropyl methyldimethoxysilane.

[0019] More preferably, the alkyl silicate is selected from at least one of methyl orthosilicate and ethyl orthosilicate.

[0020] More preferably, the mass ratio of the methacryloyloxypropyl alkoxy silicon to the alkyl silicate is (5-20):100.

[0021] More preferably, in the preparation method, the reaction temperature is 40-50° C., and the reaction time is 20-40 min.

[0022] Preferably, the particle size of the latex particles is 450 to 2000 nm.

[0023] More preferably, the particle size of the latex particles is 900 to 2000 nm.

[0024] Preferably, the particle size of the seed emulsion is 140 to 700 nm.

[0025] More preferably, the particle size of the seed emulsion is 300 to 700 nm.

[0026] The second aspect of the present invention provides a method for preparing the heat-insulating acrylic emulsion according to the first aspect, comprising the following steps:

[0027] S1, an emulsifier, an unsaturated acid, an olefin monomer, an initiator, a siloxane compound with an active group and water are reacted to prepare the seed emulsion;

[0028] S2, an emulsifier, an unsaturated acid, an olefin monomer, an initiator, a seed emulsion and water are reacted to prepare the thermal insulation acrylic emulsion.

[0029] Preferably, step S1 specifically includes the following steps: mixing an emulsifier, an unsaturated acid, an olefin monomer and water, first adding part of the initiator to carry out reaction a, then adding the remaining initiator to carry out reaction b, and finally adding a siloxane compound with an active group to carry out reaction c to obtain the seed emulsion.

[0030] More preferably, the reaction a is carried out at 80-90° C. for 10-20 min. Further preferably, the reaction a is carried out at 83-85° C. for 10-20 min.

[0031] More preferably, the reaction b is carried out at 80-90° C. for 3-5 hours. Further preferably, the reaction b is carried out at 83-85° C. for 3.5-4.5 minutes.

[0032] More preferably, the reaction c is carried out at 80-90° C. for 1 to 3 hours. Further preferably, the reaction c is carried out at 83 to 85° C. for 1.5 to 2.5 minutes.

[0033] Preferably, step S2 specifically includes the following steps: mixing the seed emulsion and water, adding part of the initiator, slowly adding a mixture consisting of an emulsifier, an unsaturated acid, an olefin monomer, and an initiator, and reacting to obtain the thermal insulation acrylic emulsion.

[0034] More preferably, in step S2, a pH regulator is added during the reaction.

[0035] More preferably, in step S2, after completion of the reaction, post-treatment is performed using tert-butyl hydroperoxide and ascorbic acid.

[0036] Preferably, the reaction temperature of the reaction in step S2 is 80-93° C. More preferably, the reaction temperature of the reaction in step S2 is 85-88° C.

[0037] The third aspect of the present invention provides use of the thermal insulation acrylic emulsion described in the first aspect in thermal insulation materials.

[0038] The fourth aspect of the present invention provides a thermal insulation coating, comprising: the thermal insulation acrylic emulsion described in the first aspect, an additive, a filler and a pigment.

[0039] The fifth aspect of the present invention provides the use of the thermal insulation coating described in the fourth aspect in building walls.

[0040] The beneficial effects of the present invention are:

[0041] The present invention provides a thermal insulating acrylic emulsion comprising hollow microspheres, forming a well-developed core-shell structure. The emulsion is prepared using raw materials including a siloxane compound with an active group, which improves the stability of the hollow microspheres during synthesis, resolving the problem of rupture during expansion. This improves the thermal insulation performance of the emulsion, resulting in a thermal insulation coating with high reflective insulation efficiency.

[0042] Specifically, compared with the prior art, the present invention has the following advantages:

[0043] 1) The heat-insulating acrylic emulsion of the present invention has a high sphericity and is free of breakage. In addition, the heat-insulating acrylic emulsion has a suitable core-shell ratio and forms a good core-shell structure, thus having excellent heat-insulating properties.

[0044] 2) During the preparation of hollow microspheres, a large negative pressure is generated during the neutralization and expansion of the hollow microspheres. If the latex particles are not stable enough, they will easily break, resulting in insufficient expansion or damage of the microspheres, which in turn affects the thermal insulation performance of the hollow microspheres. In the present invention, a siloxane compound with an active group is added to the seed emulsion, which mainly acts as a scaffold for the hollow microspheres, allowing the large-particle microspheres to expand smoothly, which is beneficial to improving the stability of the hollow microspheres during the synthesis process.

[0045] 3) The thermal insulation acrylic emulsion of the present invention can be used as a thermal insulation material in thermal insulation coatings. The thermal insulation coating of the present invention has a solar reflectance of up to 0.83, a near-infrared reflectance of up to 0.82, and a hemispherical emissivity of up to 0.92, and has great application potential in the field of building walls. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is the SEM morphology of thermal insulation acrylic emulsion 5;

[0047] Figure 2 is the SEM morphology of thermal insulation acrylic emulsion 6;

[0048] Figure 3 is the SEM morphology of thermal insulation acrylic emulsion 3;

[0049] Figure 4 This is the SEM morphology of thermal insulation acrylic emulsion 7. DETAILED DESCRIPTION

[0050] The present invention is further described in detail below through specific examples. Unless otherwise specified, the raw materials used in the following examples can be obtained from conventional commercial sources or prepared and isolated by simple synthesis; unless otherwise specified, the processes used are conventional processes in the art.

[0051] Example 1

[0052] This embodiment provides a heat-insulating acrylic emulsion with latex particles of different particle sizes, and the specific preparation method is as follows:

[0053] 1. Preparation of siloxane compounds with active groups:

[0054] First, 100 g of ethyl silicate was added to 50 g of deionized water and stirred evenly. During the stirring process, 0.01-0.05 g of glacial acetic acid was added, the temperature was raised to 40-50° C., and stirring was continued for 5 minutes. Then, 10 g of γ-methacryloxypropyltriethoxysilane monomer was dropwise added to the water. After reacting for 30 minutes, the temperature was lowered, and 0.1% (w / v) of tetrahydroxypropylethylenediamine was added to the mixture as a stabilizer. Finally, the mixture was filtered to obtain a siloxane compound with an active group, which was labeled SI-1.

[0055] 2. Preparation of different acrylic emulsion seeds The raw materials (parts by mass) are shown in Table 1, and the preparation steps are as follows:

[0056] a. Disperse the emulsifier sodium dodecylbenzenesulfonate (DS-4) in deionized water, slowly add the olefin monomer methyl methacrylate (MMA) and the unsaturated acid methacrylic acid (MAA) to the water under stirring, and disperse at a speed of 600 rpm / min for 10 minutes to prepare the pre-emulsion for dropwise addition reaction; mix the sodium persulfate and water evenly and use it as a titration initiator for later use;

[0057] b. Prepare a reaction flask, add a certain amount of water and heat it to 83-89°C, add about 2% of the pre-emulsion, add a portion of the sodium persulfate aqueous solution, maintain the reaction at 83-85°C for 15 minutes, and show a blue fluorescent state; continue to add the remaining pre-emulsion and the remaining sodium persulfate aqueous solution dropwise at 83-85°C at a uniform rate, and stir at a uniform speed for 4 hours until the reaction forms an emulsion; put the previously treated silane SI-1 into the reactor at one time, rinse with water, control the temperature to 83-85°C and keep the reaction for 2 hours, and finally cool it down and filter the emulsion to obtain acrylic seed emulsions, recorded as Seed-1 to Seed-7.

[0058] Table 1

[0059]

[0060] 3. The raw materials (parts by mass) for the preparation of different thermal insulation acrylic emulsions are shown in Table 2. The preparation steps are as follows:

[0061] The seed emulsions Seed-1 to Seed-7 were added to water, heated to 90-93°C, and sodium persulfate was added. An emulsion consisting of sodium dodecylbenzenesulfonate (DS-4), styrene (ST), methyl methacrylate (MMA), allyl methacrylate (AMA), methacrylic acid (MAA) and water, as well as sodium persulfate, was added dropwise over 150 minutes. When 45% of the emulsion was added, aqueous ammonia was added, reacted for 5 minutes, and the addition was continued. After the dropwise reaction, the temperature was lowered to 80-83°C, and a post-treatment reaction was carried out with tert-butyl hydroperoxide and ascorbic acid. The temperature was maintained for 20 minutes. The temperature was lowered to below 50°C and the product was discharged, which was recorded as thermal insulation acrylic emulsions 1-7.

[0062] Table 2

[0063]

[0064] Example 2

[0065] This example provides thermal insulation acrylic emulsions 8-9 with different core-shell ratios (different weight parts of seed emulsion). The preparation method is the same as that of Example 1. The raw materials (weight parts) are shown in Table 3:

[0066] Table 3

[0067]

[0068] Example 3

[0069] This embodiment provides thermal insulating acrylic emulsions 8-9 with different core-shell ratios. The preparation method thereof is different from that of Example 1 in that, in step 3, seed emulsion Seed-3 is added to water and the temperature is raised to 80-83°C or 85-88°C to prepare thermal insulating acrylic emulsions 10-11, respectively.

[0070] Comparative Example 1

[0071] This comparative example provides a thermal acrylic emulsion, and its preparation method is different from that of Example 1 in that the silicone compound SI-1 is not added in the preparation of the acrylic emulsion seed in step 2.

[0072] Experimental testing

[0073] 1. Test method

[0074] (1) After dispersing the heat-insulating acrylic emulsion 1-11 in anhydrous ethanol, the emulsion was dropped onto a copper mesh using a capillary tube and dried. The microscopic morphology of the emulsion was observed using a JEM-1230 transmission electron microscope.

[0075] (2) The sample particle size and particle size distribution of thermal insulation acrylic emulsion 1-11 were tested and analyzed using the NANOPHOX CS dynamic light scattering particle size analyzer from the German SYMPATEC company.

[0076] (3) According to the test criteria of JG / T 235-2014 “Architectural Reflective Thermal Insulation Coatings”, the thermal insulation acrylic emulsions 1-11 were analyzed using a portable solar spectroscopic reflectometer model AvaSR-96 and a hemispherical emissivity meter model AE1 / RD1.

[0077] 2. Test results

[0078] Figure 1-4 These are electron microscope images of thermal insulation acrylic emulsions 5, 6, 3, and 7, respectively. From the figure, we can see that before the addition amount reaches 8%, as the addition amount increases, the sphericity of the hollow microspheres increases. However, as the addition amount reaches 8%, the performance decreases. Because there is too much silane, the expansion of the hollow microspheres is affected.

[0079] Table 4 shows the particle size and thermal insulation properties of thermal insulation acrylic emulsions 1-4:

[0080] Table 4

[0081]

[0082] As shown in Table 4, different seed particle sizes have a significant impact on the particle size of the finished hollow spheres, and also significantly affect their particle size distribution. As the particle size changes, the reflectance of different light rays changes accordingly. In the particle size range of 450-1700nm, the particle size increases, and the cavity of the hollow microsphere also becomes larger, which increases the efficiency of reflective heat insulation. However, at a particle size of 2000nm, the reflective heat insulation performance decreases. The particle size is too large, and when the microspheres expand, they are not able to support them, causing the microspheres to rupture, thereby reducing the efficiency of reflective heat insulation. Therefore, when the finished particle size is 1700nm, the reflective performance is optimal.

[0083] Table 5 shows the particle size and thermal insulation performance of the acrylic emulsions of the comparative examples and thermal insulation acrylic emulsions 5-7:

[0084] Table 5

[0085]

[0086] As shown in Table 5, during the neutralization and expansion of the hollow microspheres, a significant negative pressure is generated. If the latex particles are not stable enough, they can easily break, resulting in insufficient microsphere expansion or damage, thus affecting the thermal insulation performance of the hollow microspheres. The siloxane compound SI-1 of the present invention, added to the seed emulsion, primarily acts as a scaffold for the hollow microspheres, improving the thermal insulation performance of the insulating acrylic emulsion. This, in turn, gives the thermal insulation coating prepared using it high reflective insulation efficiency.

[0087] Different silane addition levels have different effects on the efficiency of thermal insulation and reflection. At addition levels up to 8%, as the amount added increases, the sphericity of the hollow microspheres increases, and the thermal insulation and reflection efficiency improves. However, as the addition level reaches 8%, performance decreases. Excessive silane content impedes the expansion of the hollow microspheres, resulting in a decrease in thermal insulation and reflection efficiency.

[0088] Table 6 shows the particle size and thermal insulation properties of thermal insulation acrylic emulsions 8-9:

[0089] Table 6

[0090]

[0091] As can be seen from Table 6, hollow microspheres are achieved by relying on the core-shell technology in emulsion polymerization, among which the core-shell ratio is particularly critical. When the core-shell ratio is 1:9, the shell layer is too thick, which will lead to the wall thickness of the microspheres being too thick, affecting the hollowness and expansion efficiency of the microspheres; when the core-shell ratio is 3:7, the shell layer is too thin, which will result in the core layer not being able to be covered, and thus a good core-shell structure cannot be formed, affecting the reflective thermal insulation performance; it can be seen that when the core-shell ratio is 2:8, the synthesized hollow thermal insulation acrylic emulsion has the best reflective thermal insulation performance.

[0092] Table 7 shows the particle size and thermal insulation properties of thermal insulation acrylic emulsions 10-11:

[0093] Table 7

[0094]

[0095] The reaction rates of monomers vary at different temperatures. A complete core-shell structure must be formed, and starvation titration must occur during the reaction process. Only then can the shell layer more evenly cover the core layer. Furthermore, the hollow microspheres expand through acid-base neutralization. As shown in Table 7, the reflective and thermal insulation properties of the hollow microspheres increase with increasing reaction temperature. This is primarily because the core layer of the hollow microspheres is acidic, and the base needs to enter the latex particles in the later stages of synthesis to neutralize the acid. Therefore, a certain temperature is required to soften the shell layer, allowing the base to more smoothly enter the latex particles for acid-base neutralization. When the reaction temperature is 90-93°C, the resulting thermal insulation acrylic emulsion exhibits optimal thermal insulation properties.

[0096] In summary, the present invention provides a thermal insulating acrylic emulsion comprising hollow microspheres, forming a well-defined core-shell structure. The siloxane compound with active groups in the raw materials used to prepare the thermal insulating acrylic emulsion improves the stability of the hollow microspheres during the synthesis process, resolving the problem of rupture during expansion. This improves the thermal insulation performance of the thermal insulating acrylic emulsion, thereby enabling the thermal insulating coating prepared using the emulsion to possess high reflective insulation efficiency.

[0097] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A heat-insulating acrylic emulsion, characterized in that: The latex particles in the heat-insulating acrylic emulsion are hollow microspheres, and the heat-insulating acrylic emulsion comprises the following raw materials in parts by weight: 0.1 to 1 parts of emulsifier, 0.05 to 0.3 parts of unsaturated acid, 20 to 27 parts of olefin monomer, 0.05 to 0.5 parts of initiator, 7 to 25 parts of seed emulsion, and 50 to 80 parts of water; The seed emulsion comprises the following raw materials in parts by weight: 0.5 to 3 parts of an emulsifier, 5 to 20 parts of an unsaturated acid, 15 to 30 parts of an olefin monomer, 0.05 to 1 part of an initiator, 2.5 to 10 parts of a silicone compound with an active group, and 50 to 80 parts of water; The olefin monomer is selected from at least one of styrene, methyl methacrylate, butyl acrylate, acrylonitrile, and isooctyl acrylate; the siloxane compound with active groups is prepared by a preparation method comprising the following steps: methacryloxypropyl alkoxysilane reacts with alkyl silicate to prepare the siloxane compound with active groups.

2. The heat-insulating acrylic emulsion according to claim 1, characterized in that The emulsifier is selected from at least one of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, fatty alcohol polyoxyethylene ether, polyoxyethylene alkyl ester, and sodium cetyl betaine; And / or, the unsaturated acid is at least one selected from acrylic acid, methacrylic acid, itaconic acid, and fumaric acid.

3. The heat-insulating acrylic emulsion according to claim 1, characterized in that The initiator is selected from at least one of sodium persulfate, ammonium persulfate, and potassium persulfate; And / or, the raw materials of the heat-insulating acrylic emulsion further include 0.05 to 0.3 parts of a post-treatment agent; the post-treatment agent includes tert-butyl hydroperoxide and ascorbic acid.

4. The heat-insulating acrylic emulsion according to claim 1, characterized in that The methacryloxypropyl alkoxysilane is selected from at least one of γ-methacryloxypropyl trimethoxysilane, γ-methacryloxypropyl triethoxysilane and γ-methacryloxypropyl methyldimethoxysilane; And / or, the alkyl silicate is selected from at least one of methyl orthosilicate and ethyl orthosilicate.

5. The heat-insulating acrylic emulsion according to claim 1, characterized in that The particle size of the latex particles is 450 to 2000 nm; And / or, the particle size of the seed emulsion is 140 to 700 nm.

6. The method for preparing the heat insulating acrylic emulsion according to any one of claims 1 to 5, characterized in that: The steps include: S1, an emulsifier, an unsaturated acid, an olefin monomer, an initiator, a siloxane compound with an active group and water are reacted to prepare the seed emulsion; S2, an emulsifier, an unsaturated acid, an olefin monomer, an initiator, a seed emulsion and water are reacted to prepare the thermal insulation acrylic emulsion.

7. The method for preparing the heat-insulating acrylic emulsion according to claim 6, wherein: Step S1 specifically includes the following steps: mixing an emulsifier, an unsaturated acid, an olefin monomer and water, first adding part of the initiator to carry out reaction a, then adding the remaining initiator to carry out reaction b, and finally adding a siloxane compound with an active group to carry out reaction c to obtain the seed emulsion.

8. The method for preparing the heat-insulating acrylic emulsion according to claim 7, wherein: The reaction a is carried out at 80-90° C. for 10-20 minutes; And / or, the reaction b is carried out at 80-90° C. for 3-5 hours; And / or, the reaction c is carried out at 80-90° C. for 1 to 3 hours.

9. Use of the thermal insulating acrylic emulsion according to any one of claims 1 to 5 in thermal insulating materials.

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