Moisture-adjustable anti-condensation coating and preparation method thereof

Abstract

The invention relates to a humidity-adjustable anti-condensation coating which comprises the following components in parts by weight: 10-25 parts of expanded microspheres, 15-40 parts of an emulsion, 0-5 parts of rutile titanium dioxide, 1.7-5.9 parts of an auxiliary agent and the balance of water, wherein the total amount is 100 parts; the expanded microspheres are prepared by heating and expanding unexpanded microspheres at 60-80 DEG C; the emulsion is elastic acrylic emulsion and / or polyvinyl acetate emulsion. The expanded microspheres and the polymer emulsion are compounded, other porous or heat insulation materials are not needed, the formed coating can absorb a large amount of water vapor under high humidity and release the water vapor under low humidity, wall surface dew formation and mildew caused by too high environment humidity are avoided, the coating has an ultra-low heat conductivity coefficient, and the coating can be widely applied to wall surface decoration. The moisture condensation condition caused by the fact that the wall surface temperature is lower than the water vapor dew point is effectively avoided, and the excellent moisture adjusting, heat preservation and moisture condensation preventing capacities are achieved. Besides, gas is sealed in the expanded microspheres, and when external force acts on the coating, the shell of the expanded microspheres is made of the flexible polymer, so that structural damage can be reduced and the anti-condensation effect of the coating can be maintained when the expanded microspheres are subjected to the external force.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a humidity-adjustable and condensation-resistant coating and a preparation method thereof. Background Art

[0002] Damp walls or condensation on coatings often occur during the return of the south wind or in places with high humidity, such as basements. Damp walls can easily cause mold, alkali backflow, and coating peeling. Traditional moisture-proof or anti-condensation coatings are usually made from highly hygroscopic powders (such as diatomaceous earth, attapulgite, etc.) and fillers with thermal insulation properties (such as glass microspheres, expanded perlite, aerogel, etc.). They use their porosity to absorb air vapor to reduce humidity, and use the low thermal conductivity brought by the hollow structure to increase the wall temperature to above the condensation temperature of moisture in the air. For example, Chinese patent CN 112745729A discloses an anti-condensation thermal insulation latex paint, which utilizes the thermal insulation properties of microspheres, nano-silica, and aerogel to achieve thermal insulation and prevent condensation by reducing the temperature difference between the surface temperature of the object and the air temperature through the coating.

[0003] Therefore, traditional anti-condensation coatings have the following disadvantages: 1. Hollow glass microspheres and aerogels, which are more effective, have poor mechanical strength and are easily damaged during production, resulting in performance loss; 2. The formula components are complex, requiring the coordinated use of multiple powders to achieve the anti-condensation function, which is not easy to produce. In addition, hollow glass microspheres and aerogels are easy to fly and difficult to operate; 3. The resulting paint film is too brittle and easily damaged by foreign objects, and does not have the function of protecting the decorated surface.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a humidity-adjustable anti-condensation coating and a preparation method thereof.

[0006] The technical solution adopted in the present invention is:

[0007] In one aspect, the present invention provides a humidity-adjustable anti-condensation coating, comprising, by weight:

[0008] 10-25 parts of expanded microspheres, 15-40 parts of emulsion, 0-5 parts of rutile titanium dioxide, 1.7-5.9 parts of additives, and water to 100 parts;

[0009] The expanded microspheres are obtained by heating and expanding unexpanded microspheres at 60-80°C.

[0010] The emulsion is elastic acrylic emulsion and / or polyvinyl acetate emulsion.

[0011] The present invention proposes a humidity-adjustable, anti-condensation coating that utilizes a composite of expanded microspheres and a polymer emulsion. This coating, without the need for other porous or thermally insulating materials, absorbs large amounts of water vapor at high humidity and releases it at low humidity, preventing condensation and mold on walls caused by excessive humidity. The coating also exhibits an ultra-low thermal conductivity, effectively preventing condensation caused by wall temperatures below the dew point, resulting in excellent humidity-adjusting, heat-insulating, and anti-condensation capabilities. Furthermore, because the expanded microspheres contain enclosed gas, when an external force acts on the coating, the flexible polymer shell of the expanded microspheres deforms under the force. This compression of the internal gas also compresses the coating, which then rebounds when the external force is removed. Consequently, mechanical stress can be minimized, thereby maintaining the coating's anti-condensation properties. In particular, when the emulsion is preferably an elastic emulsion, the resilience of the expanded microspheres can be further enhanced, making their structure more stable and complete, thereby improving the coating's anti-condensation performance.

[0012] Preferably, the weight ratio of the emulsion to the expanded microspheres is 0.6-2:1.

[0013] Preferably, the expanded microspheres are spherical polymers with a diameter of less than 100 μm.

[0014] Preferably, the auxiliary agents include, by weight: 0.2-0.5 parts of cellulose ether, 0.1-0.2 parts of pH regulator, 0.5-1 parts of dispersant, 0.2-1 parts of wetting agent, 0.1-0.5 parts of defoaming agent, 0.5-1 parts of antifreeze agent, 0.1-0.5 parts of preservative, and 0-1.2 parts of film-forming aid.

[0015] More preferably, the pH regulator is AMP-95;

[0016] The dispersant is a sodium salt of polycarboxylate;

[0017] The wetting agent is an alkyl polyoxyethylene ether;

[0018] The defoaming agent is polysiloxane;

[0019] The antifreeze agent is ethylene glycol or propylene glycol;

[0020] The preservative is an isothiazolinone derivative;

[0021] The film-forming aid is alcohol ester dodecahydrate.

[0022] Another aspect of the present invention provides a method for preparing a humidity-adjustable anti-condensation coating as described in any of the above technical solutions, comprising the following steps:

[0023] At a speed of less than 500 rpm, add part of the additives to the water and stir for 1-2 minutes. Then add rutile titanium dioxide, adjust the speed to 1500 rpm, stir for 10-15 minutes, then add the emulsion, adjust the speed to 500 rpm and stir for 2-5 minutes. Finally, add the expanded microspheres and the remaining additives and disperse them evenly. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are further described in detail below through specific examples.

[0025] In one aspect, the present invention provides a humidity-adjustable anti-condensation coating, comprising, by weight:

[0026] 10-25 parts of expanded microspheres, 15-40 parts of emulsion, 0-5 parts of rutile titanium dioxide, 1.7-5.9 parts of additives, and water to 100 parts;

[0027] Expanded microspheres are obtained by heating unexpanded microspheres at 60-80°C and expanding them.

[0028] The emulsion is an elastic acrylic emulsion and / or a polyvinyl acetate emulsion.

[0029] In the present invention, the heating expansion temperature of the expanded microspheres is selected to be 60-80°C, which is close to or slightly higher than the initial expansion temperature of the expanded microspheres. At this time, the shell of the expanded microspheres begins to soften, the low-boiling point liquid hydrocarbons inside partially vaporize, and closed pores are mainly formed on the surface, so that the expanded microspheres have a certain elastic deformation recovery ability, which is conducive to achieving a long-term anti-condensation effect. If the heating expansion temperature is too high (especially >100°C), the shell is fully softened, and the internal gas pressure causes the expanded microspheres to over-expand or even rupture, forming an open pore structure and losing the elastic recovery ability, which is not conducive to the thermal insulation and anti-condensation effects of the coating.

[0030] In some preferred embodiments of the present invention, the weight ratio of the emulsion to the expanded microspheres is 0.6-2:1.

[0031] In the present invention, the weight ratio of the emulsion to the expanded microspheres is controlled to 0.6-2:1 so that the compounding of the two can achieve a better elastic effect and improve the anti-condensation performance of the coating. If the proportion of the emulsion is too high, it will be detrimental to the humidity control performance and anti-condensation performance of the coating, and the elasticity of the coating will also decrease.

[0032] In some preferred embodiments of the present invention, the expanded microspheres are spherical polymers having a diameter of less than 100 μm.

[0033] In the present invention, for example, the expanded microspheres may be EC-WE81501L produced by Shanghai Zhuojie.

[0034] In some preferred embodiments of the present invention, the additives include, by weight: 0.2-0.5 parts of cellulose ether, 0.1-0.2 parts of pH regulator, 0.5-1 parts of dispersant, 0.2-1 parts of wetting agent, 0.1-0.5 parts of defoaming agent, 0.5-1 parts of antifreeze agent, 0.1-0.5 parts of preservative, and 0-1.2 parts of film-forming aid.

[0035] In some more preferred embodiments of the present invention, the pH adjuster is AMP-95;

[0036] The dispersant is sodium polycarboxylate;

[0037] The wetting agent is an alkyl polyoxyethylene ether;

[0038] The defoaming agent is polysiloxane;

[0039] Antifreeze is ethylene glycol or propylene glycol;

[0040] The preservative is an isothiazolinone derivative;

[0041] The film-forming aid is alcohol ester dodecahydrate.

[0042] Another aspect of the present invention provides a method for preparing a humidity-adjustable anti-condensation coating according to any one of the above technical solutions, comprising the following steps:

[0043] At a speed of less than 500 rpm, add part of the additives to the water and stir for 1-2 minutes. Then add rutile titanium dioxide, adjust the speed to 1500 rpm, stir for 10-15 minutes, then add the emulsion, adjust the speed to 500 rpm and stir for 2-5 minutes. Finally, add the expanded microspheres and the remaining additives and disperse them evenly.

[0044] Example 1

[0045] A humidity-adjustable anti-condensation coating comprising, by weight:

[0046] 20 parts of expanded microspheres, 20 parts of elastic acrylic emulsion, 2.9 parts of additives (0.4 parts of cellulose ether, 0.1 parts of pH regulator, 0.9 parts of dispersant, 0.6 parts of wetting agent, 0.3 parts of defoaming agent, 0.5 parts of antifreeze agent, 0.1 parts of preservative), and water to 100 parts.

[0047] The expanded microspheres are obtained by heating and expanding unexpanded microspheres at 70°C. They are spherical polymers with a diameter of less than 100 μm and a thermal conductivity of 0.025 W / m·K.

[0048] The pH regulator was AMP-95;

[0049] The dispersant is sodium polycarboxylate;

[0050] The wetting agent is an alkyl polyoxyethylene ether;

[0051] The defoaming agent is polysiloxane;

[0052] The antifreeze is ethylene glycol;

[0053] The preservative is an isothiazolinone derivative.

[0054] It is prepared by the following method, comprising the following steps:

[0055] At a speed of 300 rpm, add cellulose ether, pH regulator, dispersant, wetting agent, defoaming agent, and antifreeze into water and stir for 1 minute. Then add elastic acrylic emulsion, adjust the speed to 500 rpm and stir for 2 minutes. Finally, add expanded microspheres and preservatives and disperse them evenly to obtain the product.

[0056] Example 2

[0057] The main difference between this embodiment and embodiment 1 is that the type of emulsion and the amount of each component used are different.

[0058] A humidity-adjustable anti-condensation coating comprising, by weight:

[0059] 25 parts of expanded microspheres, 30 parts of polyvinyl acetate emulsion, 3.6 parts of additives (0.2 parts of cellulose ether, 0.1 parts of pH regulator, 1 part of dispersant, 1 part of wetting agent, 0.5 parts of defoaming agent, 0.5 parts of antifreeze agent, 0.3 parts of preservative), and water to make up to 100 parts.

[0060] The preparation method of the coating of this embodiment is the same as that of Example 1.

[0061] Example 3

[0062] The main difference between this embodiment and embodiment 1 is that the amounts of the components are different.

[0063] A humidity-adjustable anti-condensation coating comprising, by weight:

[0064] 20 parts of expanded microspheres, 15 parts of elastic acrylic emulsion, 3.3 parts of additives (0.5 parts of cellulose ether, 0.1 parts of pH regulator, 0.9 parts of dispersant, 0.5 parts of wetting agent, 0.5 parts of defoaming agent, 0.5 parts of antifreeze agent, 0.3 parts of preservative), and water to 100 parts.

[0065] The preparation method of the coating of this embodiment is the same as that of Example 1.

[0066] Example 4

[0067] The main difference between this embodiment and embodiment 1 is that rutile titanium dioxide is added.

[0068] A humidity-adjustable anti-condensation coating comprising, by weight:

[0069] 20 parts of expanded microspheres, 20 parts of elastic acrylic emulsion, 5 parts of rutile titanium dioxide, 2.9 parts of additives (0.4 parts of cellulose ether, 0.1 parts of pH adjuster, 0.9 parts of dispersant, 0.6 parts of wetting agent, 0.3 parts of defoamer, 0.5 parts of antifreeze, 0.1 parts of preservative), and water to 100 parts.

[0070] It is prepared by the following method, comprising the following steps:

[0071] At a speed of 300 rpm, add cellulose ether, pH regulator, dispersant, wetting agent, defoaming agent, and antifreeze into water and stir for 1 minute. Then add rutile titanium dioxide and adjust the speed to 1500 rpm and stir for 10 minutes. Then add elastic acrylic emulsion and adjust the speed to 500 rpm and stir for 2 minutes. Finally, add expanded microspheres and preservatives and disperse them evenly to obtain the product.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that diatomaceous earth (thermal conductivity greater than 0.1 W / m·K) is used in equal amounts to replace the expanded microspheres.

[0074] The preparation method of the coating of this comparative example is the same as that of Example 1.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 1 is that hollow glass microspheres (thermal conductivity 0.03 W / m·K) are used in equal amounts to replace the expanded microspheres.

[0077] The preparation method of the coating of this comparative example is the same as that of Example 1.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that an equal amount of silica aerogel (thermal conductivity: 0.018 W / m·K) is used to replace the expanded microspheres.

[0080] The preparation method of the coating of this comparative example is the same as that of Example 1.

[0081] Comparative Example 4

[0082] The difference between this comparative example and Example 1 is that 10 parts of diatomaceous earth (thermal conductivity greater than 0.1 W / m·K) and 20 parts of hollow glass microspheres (thermal conductivity 0.03 W / m·K) are used to replace the 20 parts of expanded microspheres in Example 1, and the amount of water used is reduced accordingly.

[0083] The preparation method of the coating of this comparative example is the same as that of Example 1.

[0084] Comparative Example 5

[0085] The main difference between this comparative example and Example 1 is that the 20 parts of expanded microspheres in Example 1 are adjusted to 10 parts, the 20 parts of elastic acrylic emulsion are adjusted to 40 parts, and the amount of water is reduced accordingly.

[0086] The preparation method of the coating of this comparative example is the same as that of Example 1.

[0087] Comparative Example 6

[0088] The main difference between this comparative example and Example 1 is that the emulsion type is different and a film-forming aid is added.

[0089] A coating comprising, by weight:

[0090] 20 parts of expanded microspheres, 20 parts of high Tg acrylic emulsion (Tg>20℃), 4.1 parts of additives (0.4 parts of cellulose ether, 0.1 parts of pH regulator, 0.9 parts of dispersant, 0.6 parts of wetting agent, 0.3 parts of defoaming agent, 0.5 parts of antifreeze agent, 0.1 parts of preservative, 1.2 parts of alcohol ester film-forming aid), and water to 100 parts.

[0091] It is prepared by the following method, comprising the following steps:

[0092] At a speed of 300 rpm, add cellulose ether, pH regulator, dispersant, wetting agent, defoaming agent, and antifreeze into water and stir for 1 minute. Then add elastic acrylic emulsion and film-forming aid, adjust the speed to 500 rpm and stir for 2 minutes. Finally, add expanded microspheres and preservatives and disperse them evenly to obtain the product.

[0093] Comparative Example 7

[0094] The main difference between this comparative example and Example 1 is that an equal amount of unfoamed expandable microspheres are used to replace the expanded microspheres, and then post-electric heating (70° C.) is used to expand the paint applied on the wall.

[0095] The coatings prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance tests, and the results are recorded in Table 1. The test method is as follows:

[0096] Moisture absorption and dehumidification: refer to the international standard ISO 24353-2008 and NORDTEST test, place the sample dried to constant weight in a constant temperature and humidity chamber, with the ambient temperature and relative humidity set at 23°C and 30% respectively. This process lasts for 24 hours to allow the sample to reach a constant weight. Then, the sample is allowed to absorb moisture at 70% relative humidity for 12 hours, and then dehumidify at 30% RH for 12 hours.

[0097] Initial dew point and condensation amount: Tested in accordance with standard HG / T 4560-2013 "Test method for anti-condensation performance of coatings";

[0098] Thermal conductivity: Tested in accordance with GB / T 10295-2008;

[0099] Paint film elasticity: score is determined by finger pressing comparison test method. The higher the score, the better the paint film resilience.

[0100] Paint film smoothness: Touch the paint film surface with your hand and score it based on the roughness or concave-convex feeling. The higher the score, the better the paint film smoothness.

[0101] Table 1 Test results

[0102]

[0103] As shown in Table 1, comparing Examples 1-3 with Comparative Example 5 shows that, in the emulsion-expanded microsphere ratio, as the emulsion proportion increases, the coating's humidity-control ability and anti-condensation performance decrease, and the film's elasticity also decreases. Comparing Example 1 with Example 4 shows that adding some titanium dioxide to the coating system for color adjustment does not affect the system's overall performance. Comparing Example 1 with Comparative Examples 1-4 shows that using traditional porous or hollow hygroscopic anti-condensation fillers, due to their rigidity and higher density, results in inferior moisture absorption and anti-condensation performance compared to expanded microspheres for the same mass. Furthermore, the structure easily breaks when subjected to external forces, making it impossible to recover and lacking elasticity. Furthermore, the paint films obtained using diatomaceous earth and hollow glass microspheres as anti-condensation fillers are less smooth than those obtained with expanded microspheres. Comparing Example 1 with Comparative Example 6 shows that, due to the use of a high-Tg acrylic emulsion in Comparative Example 6, the film's elasticity decreases, and the coating's humidity-control and anti-condensation performance also slightly decreases. By comparing Example 1 and Comparative Example 7, it can be seen that since Comparative Example 7 uses unfoamed expanded microspheres and then uses electric heating to foam the coating, the foaming will be incomplete due to the limitation of the emulsion, and the anti-condensation performance and thermal insulation performance of the coating will be inferior to those of Example 1 using expanded microspheres; and the post-heating foaming method will cause the coating to not only lose its elasticity but also become rough and uneven, and can only be applied under the putty layer, and has no decorative effect of the topcoat coating.

[0104] In summary, the humidity-adjustable anti-condensation coating of the present invention has the following advantages:

[0105] 1. The coating prepared by combining the expanded microspheres with the elastic acrylic emulsion of the present invention has excellent humidity control, heat preservation and anti-condensation properties.

[0106] 2. The expanded microspheres used are organic polymers. The gas encapsulated inside will not leak. They have flexibility that traditional rigid porous or hollow materials do not have. The prepared coating can have good rebound recovery performance after being subjected to force and will not collapse directly like traditional hollow microspheres and aerogels.

[0107] 3. Since the expanded microspheres have good elasticity, they will not be destroyed during production due to excessive stirring speed, which will lead to performance degradation, unlike traditional hollow microspheres or aerogels. They are easier to produce and apply on a large scale.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A humidity-adjustable anti-condensation coating, characterized in that: Including by weight: 10-25 parts of expanded microspheres, 15-40 parts of emulsion, 0-5 parts of rutile titanium dioxide, 1.7-5.9 parts of additives, and water to 100 parts; The expanded microspheres are obtained by heating and expanding unexpanded microspheres at 60-80°C. The emulsion is elastic acrylic emulsion and / or polyvinyl acetate emulsion.

2. The humidity-adjustable anti-condensation coating according to claim 1, characterized in that: The weight ratio of the emulsion to the expanded microspheres is 0.6-2:

1.

3. The humidity-adjustable anti-condensation coating according to claim 1, characterized in that: The expanded microspheres are spherical polymers with a diameter of less than 100 μm.

4. The humidity-adjustable anti-condensation coating according to claim 1, characterized in that: The auxiliary agents include, by weight, 0.2-0.5 parts of cellulose ether, 0.1-0.2 parts of pH regulator, 0.5-1 parts of dispersant, 0.2-1 parts of wetting agent, 0.1-0.5 parts of defoaming agent, 0.5-1 parts of antifreeze agent, 0.1-0.5 parts of preservative, and 0-1.2 parts of film-forming auxiliary agent.

5. The humidity-adjustable anti-condensation coating according to claim 4, characterized in that: The pH regulator is AMP-95; The dispersant is a sodium salt of polycarboxylate; The wetting agent is an alkyl polyoxyethylene ether; The defoaming agent is polysiloxane; The antifreeze agent is ethylene glycol or propylene glycol; The preservative is an isothiazolinone derivative; The film-forming aid is alcohol ester dodecahydrate.

6. A method for preparing the humidity-adjustable anti-condensation coating according to any one of claims 1 to 5, comprising the following steps: At a speed of less than 500 rpm, add part of the additives to the water and stir for 1-2 minutes. Then add rutile titanium dioxide, adjust the speed to 1500 rpm, stir for 10-15 minutes, then add the emulsion, adjust the speed to 500 rpm and stir for 2-5 minutes. Finally, add the expanded microspheres and the remaining additives and disperse them evenly.

Images