Coating material for frost-retarding coating layer, preparation method therefor and use thereof

Abstract

The present invention provides a coating material for a frost-retarding coating layer, a preparation method therefor, and a use thereof. On the basis of the total mass of the coating material being 100%, the coating material comprises the following components in percentages by mass: 30-50% of a graft-modified polymer, 1-15% of a functional additive, and the balance of a first solvent, wherein the graft-modified polymer is a polymer prepared by mixing reactants, and the reactants include a hydrophilic polymer, a hydrophobic polymer, a graft modification aid, and a second solvent. The frost-retarding coating layer of the present invention has the advantages of both hydrophilic and hydrophobic coating layers. After being applied to fins of a heat exchanger, the frost-retarding coating layer can make water drops rapidly slide off without obvious water trace left, thus avoiding the formation of dense frosts on the surfaces of the fins of the heat exchanger during working under frosting working conditions.

Description

A coating for delaying frost formation, and its preparation method and application Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a coating for delaying frost formation, a preparation method and an application thereof. Background Art

[0002] The fins in air conditioner heat exchangers are mostly made of aluminum foil coated with a hydrophilic coating. With the advancement of technology and the industry trend towards environmental protection and energy conservation, air conditioner manufacturers have placed increasingly higher demands on the functionality of hydrophilic coated aluminum foil. When the outdoor temperature is low (close to 0°C) and the air humidity is high in the air conditioner outdoor unit of residential / commercial buildings, the outdoor unit heat exchanger is prone to frost and freezing, affecting the heat exchange effect. In response to this, almost all air conditioner outdoor units use reverse cycle defrosting. This operation consumes an additional 10% to 15% of electricity, increasing energy consumption. Improving this phenomenon has become the key to the development of air conditioner outdoor unit coatings.

[0003] In principle, the frosting process in a heat exchanger is essentially the process of the heat exchanger absorbing the latent heat of water vapor in the air. After the water vapor transfers the latent heat of liquefaction to the heat exchanger surface, it immediately loses the latent heat of vaporization and becomes solid frost particles that adhere to the heat exchanger surface. During this process, some frost particles are blown away from the frost layer by the wind, while more continue to accumulate and thicken the frost layer. Water vapor in the air first undergoes heterogeneous nucleation on the cold surface. The condensation nuclei continue to grow and merge to form macroscopic condensation droplets. As the droplet temperature drops and freezes, frost crystals form on the surface of the frozen droplets. The frost crystals continue to grow, gradually forming a frost layer. When the supercooling of the frost layer surface approaches zero, the frost layer no longer grows in height. Water vapor diffuses into the frost layer gaps to form frost crystals, increasing the density of the frost layer.

[0004] Based on this, reducing the probability of water vapor in the air forming droplets on the surface of the heat exchanger or preventing droplets from remaining on the surface of the heat exchanger becomes the key to solving the problem. The former is limited by the external climate, and there is little room for human improvement, and research has not yet made a breakthrough. The latter, on the other hand, puts forward new requirements for the coating of the heat exchanger. Studies have shown that hydrophilic treatment of the heat exchanger fins has excellent drainage performance, and water vapor is not easy to form droplets. However, obvious traces of water droplets sliding off will remain, resulting in the formation of dense frost. On the contrary, if the heat exchanger fins are hydrophobic treatment, water droplets are not easy to slide off. After condensation, water vapor will become sparse droplets and remain on the fins. Over time, sparse frost will form. However, since the droplets are not easy to slide off, as the air conditioner continues to run, they will block the drainage channel, which has a great impact on the normal operation of the air conditioner.

[0005] Patent application number CN 112322164 A describes a surface treatment agent that delays frosting on radiator aluminum fins. This agent is applied to the surface of the radiator aluminum fins to form a coating, thereby delaying frosting. However, the invention limits the material used to polyurethane resin, which is expensive, and the frosting-delaying effect is not clearly stated, making it difficult to achieve reasonable industrial production.

[0006] Patent application number CN 102549079 A describes a resin material with excellent frost-suppressing properties, fabricated into a laminated metal plate capable of suppressing frost formation. However, the actual structure of the invention is a three-layer structure consisting of a frost-suppressing resin, an inorganic oxide (organic-inorganic composite oxide), and a metal plate. The introduction of an inorganic oxide layer increases processing difficulty and production costs. Furthermore, the document does not provide information on the specific composition of the intermediate layer, odor, compatibility, and other factors.

[0007] Summary of the Invention

[0008] In view of the technical problems that the fins of existing heat exchangers are prone to frost and liquid droplets are difficult to slide off, the present invention provides a coating for a frost-retarding coating and its preparation method and application.

[0009] On the one hand, the present invention provides a coating for a frost-retarding coating, which includes the following components in mass percentage based on the mass of the coating for the frost-retarding coating as 100%: 30% to 50% of a grafted modified polymer, 1% to 15% of a functional additive, and the remainder being a first solvent; the grafted modified polymer is a polymer prepared by mixing reactants, and the reactants include a hydrophilic polymer, a hydrophobic polymer, a grafted modified additive and a second solvent, and the grafted modified polymer has a structure of alternating hydrophilic microregions and hydrophobic microregions, and exhibits a macroscopic performance of retarding frost.

[0010] Optionally, the hydrophilic polymer is obtained by copolymerizing at least one monomer selected from the group consisting of an amide monomer and a sulfonic acid monomer with an acrylic acid monomer, wherein the mass of the acrylic acid monomer is 50% to 80% of the mass of the hydrophilic polymer; the structural formula of the hydrophilic polymer is as shown in Formula 1.

[0011] In formula I, a, b, c, d, and e are not all 0, and f is an integer greater than 0.

[0012] Optionally, the hydrophobic polymer is obtained by copolymerizing at least one monomer selected from vinyl monomers and silicone monomers with a fluorine-containing monomer, the mass of the fluorine-containing monomer is 10% to 40% of the mass of the hydrophobic polymer, and the fluorine content of the fluorine-containing monomer is 20% to 70%.

[0013] Optionally, the grafting modification auxiliary agent includes at least one of a silane coupling agent and a titanate coupling agent, the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane and vinyltriethoxysilane; the titanate coupling agent includes an oxyacetoxy chelate titanate coupling agent.

[0014] Optionally, the mass of the hydrophilic polymer is 20% to 50% of the mass of the grafted modified polymer, the hydrophobic polymer is 10% to 30% of the mass of the grafted modified polymer, the grafted modification auxiliary agent is 0.1% to 5% of the mass of the grafted modified polymer, and the second solvent includes water.

[0015] Optionally, the first solvent includes an organic solvent and water, and the mass of the organic solvent is 0.1% to 5% of the mass of the frost-retarding coating.

[0016] Optionally, the organic solvent includes an alcohol solvent and / or an ether solvent, the alcohol solvent includes one or more of ethanol, isopropanol, and butanol, and the ether solvent includes one or more of ethylene glycol ethyl ether and ethylene glycol tert-butyl ether.

[0017] Optionally, the functional additive includes one or more of a curing agent, a defoaming agent, a wetting agent and a rheological additive;

[0018] The curing agent includes at least one of a polyisocyanate compound and a cyanamide compound;

[0019] The defoaming agent includes at least one of an organosilicon compound and mineral oil;

[0020] The wetting agent includes at least one of a silicone compound and a fluorocarbon compound;

[0021] The rheology modifier includes a polyurethane associative compound.

[0022] On the other hand, the present invention also provides a method for preparing a coating for the frost-retarding coating as described in any one of the above items, comprising the following steps:

[0023] The hydrophilic polymer is dissolved in the second solvent, and then the hydrophobic polymer and the graft modification auxiliary agent are sequentially added to the hydrophilic polymer to react to obtain the graft modified polymer; 1% to 15% of the functional auxiliary agent is dissolved in the first solvent, and then 30% to 50% of the graft modified polymer is added to the functional auxiliary agent, and stirred to obtain the frost-retarding coating.

[0024] On the other hand, the present invention also provides a use of the coating material used for the frost-retarding coating as described in any one of the above items in the field of surface treatment of fins of air-conditioning heat exchangers.

[0025] Optionally, a coating with the ability to delay frost formation can be formed by coating the coating material used for the frost-retarding coating as described in any of the above items on the surface of the fin with the anti-corrosion primer.

[0026] In the present invention, a grafted modified polymer is prepared by mixing reactants including a hydrophilic polymer and a hydrophobic polymer. This results in a frost-retarding coating with the grafted modified polymer having a structure that alternates between hydrophilic and hydrophobic layers, combining the advantages of both hydrophilic and hydrophobic coatings. When applied to the fins of a heat exchanger, it allows water droplets to slide off quickly without leaving noticeable traces, significantly reducing residual water marks on the coating. This prevents the formation of dense frost on the heat exchanger surface and reduces the frequency of frost buildup on the outdoor unit. The coating used in the frost-retarding coating of the present invention is simple to prepare, requires minimal production equipment, generates no waste during production, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a simulation experimental device for the application of a coating for delaying frost formation;

[0028] FIG2 is a sample obtained by simulating the sample of Example 1 and Comparative Example 1 using the apparatus of FIG1 ;

[0029] FIG3 is a comparison of microscopic and macroscopic images of simulated freezing and thawing of the samples of Example 1 and Comparative Example 1;

[0030] FIG4 is a schematic diagram of a frost-retarding coating provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] In order to illustrate the technical solution of the present invention, specific embodiments are provided below.

[0033] In one embodiment of the present invention, a coating for a frost-retarding coating comprises the following components by weight, based on 100% of the coating: 30% to 50% of a graft-modified polymer, 1% to 15% of a functional additive, and the remainder being a first solvent. The graft-modified polymer is prepared by mixing reactants, including a hydrophilic polymer, a hydrophobic polymer, a graft-modified additive, and a second solvent.

[0034] In this embodiment, a grafted modified polymer is prepared by mixing reactants including a hydrophilic polymer and a hydrophobic polymer. This results in a frost-retarding coating with the grafted modified polymer having a structure that alternates between hydrophilic and hydrophobic layers, combining the advantages of both hydrophilic and hydrophobic coatings. When applied to the fins of a heat exchanger, water droplets slide off quickly without leaving noticeable traces, significantly reducing residual water marks on the coating. This prevents the formation of dense frost on the heat exchanger surface and reduces the frequency of frost buildup on the outdoor unit. The frost-retarding coating of the present invention has a simple preparation process, requires minimal production equipment, generates no waste, and is environmentally friendly.

[0035] In some embodiments of the present invention, the hydrophilic polymer is obtained by copolymerizing at least one of an amide monomer and a sulfonic acid monomer with an acrylic acid monomer. The mass of the acrylic acid monomer accounts for 50% to 80% of the mass of the hydrophilic polymer, thereby ensuring the hydrophilicity of the hydrophilic polymer. The hydrophilic polymer structural formula is shown in Formula 1.

[0036] In formula I, a, b, c, d, and e are not all 0, and f is an integer greater than 0.

[0037] In some embodiments of the present invention, the hydrophobic polymer is obtained by copolymerizing at least one monomer selected from vinyl monomers and silicone monomers with a fluorine-containing monomer, and the mass of the fluorine-containing monomer is 10% to 40% of the mass of the hydrophobic polymer, thereby ensuring the hydrophobicity of the hydrophobic polymer.

[0038] In some embodiments of the present invention, the organosilicon monomer includes but is not limited to polydimethylsiloxane. The fluorine-containing monomer includes but is not limited to at least one of polyvinylidene fluoride and polytetrafluoroethylene. The vinyl monomer includes but is not limited to at least one of polyethylene and polypropylene.

[0039] In some embodiments of the present invention, the graft modification agent includes at least one of a silane coupling agent and a titanate coupling agent, wherein the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane and vinyltriethoxysilane. The titanate coupling agent includes an oxoacetoxy chelate titanate coupling agent.

[0040] In some embodiments of the present invention, the mass of the hydrophilic polymer is 20% to 50% of the mass of the grafted modified polymer, the hydrophobic polymer is 10% to 30% of the mass of the grafted modified polymer, the grafted modification auxiliary agent is 0.1% to 5% of the mass of the grafted modified polymer, and the second solvent includes water.

[0041] In some embodiments of the present invention, the first solvent includes an organic solvent and water, and the mass of the organic solvent is 0.1% to 5% of the mass of the frost-retarding coating.

[0042] In some embodiments of the present invention, the organic solvent includes an alcohol solvent and / or an ether solvent, the alcohol solvent includes one or more of ethanol, isopropanol, and butanol, and the ether solvent includes one or more of ethylene glycol ethyl ether and ethylene glycol tert-butyl ether.

[0043] In some embodiments of the present invention, the functional additive includes one or more of a curing agent, a defoaming agent, a wetting agent, and a rheological additive.

[0044] The curing agent includes at least one of a polyisocyanate compound and a cyanamide compound.

[0045] The defoaming agent includes at least one of an organic silicon compound and mineral oil.

[0046] The wetting agent includes at least one of a silicone compound and a fluorocarbon compound.

[0047] The rheological modifier includes a polyurethane composite compound.

[0048] On the other hand, an embodiment of the present invention further provides a method for preparing a coating for the frost-retarding coating as described in any one of the above items, comprising the following steps:

[0049] The hydrophilic polymer is dissolved in the second solvent, and then the hydrophobic polymer and the graft modification auxiliary agent are sequentially added to the hydrophilic polymer to react to obtain the graft modified polymer.

[0050] 1% to 15% of the functional auxiliary agent is dissolved in the first solvent, and then 30% to 50% of the graft-modified polymer is added to the functional auxiliary agent, and the mixture is stirred to obtain the coating for the frost-retarding coating.

[0051] Specifically, in some embodiments of the present invention, 30 to 50 parts by mass of a hydrophilic polymer and 15 to 50 parts by mass of water are added to a container. Under a nitrogen atmosphere, the rotation speed is increased to 200 to 600 rpm at 50 to 150°C and stirred until uniform. Subsequently, 0.1 to 5 parts by mass of a grafting modification agent and 10 to 30 parts by mass of a hydrophobic polymer are added with stirring at 200 to 600 rpm. After stirring for 5 to 30 minutes, a grafted modified polymer is obtained. The total amount of the hydrophilic polymer, water, organic solvent, grafting modification agent, and hydrophobic polymer components is 100 parts by mass.

[0052] At 25-30°C, mix 30-70 parts by mass of water, 0.1-5 parts by mass of an organic solvent, and 1-15 parts of a functional additive in a container. Stir at 200-600 rpm and atmospheric pressure for 3-10 minutes. After uniform stirring, add 30-50 parts by mass of a graft-modified polymer and stir at 500-800 rpm for 5-20 minutes to obtain a uniform emulsion, which is the coating for the frost-retarding coating. The total amount of this coating is 100 parts by mass.

[0053] On the other hand, an embodiment of the present invention further provides a use of a coating for the frost-retarding coating as described in any one of the above items in the field of surface treatment of fins of an air-conditioning heat exchanger.

[0054] In some embodiments of the present invention, a coating having frost-retarding properties can be formed by applying the coating used for the frost-retarding coating described in any of the above items to a fin surface having an anti-corrosion primer. The present invention is further illustrated by the following examples. The reagents used in the following examples are all commercially available.

[0055] Example 1

[0056] S1: Synthesis of graft-modified polymers

[0057] 35 parts by mass of a hydrophilic polymer (copolymerized with acrylic acid and sulfonic acid in a 2:1 mass ratio) and 49.8 parts by mass of water were added to a container, filled with nitrogen, heated to 80°C, and stirred at 500 rpm until uniform. Subsequently, 0.2 parts by mass of γ-aminopropyltriethoxysilane and 15 parts by mass of a hydrophobic polymer (polymerized with polyvinylidene fluoride and organosilicon in a 1:4 mass ratio) were added with stirring, and stirred for 5 minutes to obtain a grafted modified polymer.

[0058] S2: Configuration of coatings used for frost-retarding coatings

[0059] At 25-30°C, 52 parts by mass of water, 1 part by mass of ethylene glycol ethyl ether solvent, 0.5 parts by mass of a polysiloxane wetting agent, 2 parts by mass of a polyurethane-based rheological modifier, and 4.5 parts by mass of a cyanamide curing agent were mixed in a container and stirred at 300 rpm for 5 minutes. After uniform stirring, 40 parts by mass of a graft-modified polymer was added, and the speed was increased to 600 rpm and stirred for 10 minutes to obtain a uniform emulsion, namely the anti-frost coating.

[0060] The total mass parts of the above-mentioned S1 graft modified polymer is 100 parts, and the total mass parts of S2 frost-retarding coating material is 100 parts. The mass parts of S1 and S2 are calculated separately.

[0061] When applying, this coating can be topcoated with the primer commonly used for the heat exchanger fins of conventional air conditioner outdoor units.

[0062] Example 2

[0063] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S1, 40 parts by mass of hydrophilic polymer, 49.5 parts by mass of water, 0.5 parts by mass of γ-aminopropyltriethoxysilane, and 10 parts by mass of hydrophobic polymer are included.

[0064] In S2, 51.8 parts by mass of water, 1 part by mass of ethylene glycol tert-butyl ether solvent, 0.2 parts by mass of fluorocarbon wetting agent, 2 parts by mass of polyurethane composite rheological additive, 5 parts by mass of polyisocyanate curing agent, and 40 parts by mass of graft modified polymer.

[0065] Example 3

[0066] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S1, the hydrophilic resin is obtained by copolymerizing acrylic acid monomer and amide monomer in a mass ratio of 2:1.

[0067] Example 4

[0068] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S1, the hydrophilic polymer is an acrylic acid monomer polymer.

[0069] Example 5

[0070] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S1, the hydrophilic polymer is obtained by copolymerizing acrylic acid monomer and sulfonic acid monomer in a mass ratio of 1:2.

[0071] Example 6

[0072] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S1, the hydrophobic polymer is obtained by polymerizing polyvinylidene fluoride and organosilicon monomer in a mass ratio of 1:19.

[0073] Example 7

[0074] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S2, the graft-modified polymer is 30 parts by mass and water is 62 parts by mass.

[0075] Example 8

[0076] In this embodiment, the specific implementation is similar to that of Example 1, except that: in S2, the graft-modified polymer is 50 parts by mass and the water is 42 parts by mass.

[0077] Comparative Example 1

[0078] In this comparative example, the specific implementation is similar to that of Example 1, except that: in S1, 50 parts by mass of hydrophilic polymer are used, the addition of hydrophobic polymer and graft modification auxiliary agent is omitted, and 50 parts by mass of water are added and stirred evenly to obtain a hydrophilic resin.

[0079] In S2, the graft-modified polymer is replaced with an equal amount of hydrophilic resin, and a comparative sample is obtained after the configuration is completed.

[0080] Comparative Example 2

[0081] In this comparative example, the specific implementation is similar to that of Example 1, except that: in S1, 50 parts by mass of hydrophobic polymer is used, the addition of hydrophilic polymer and graft modification auxiliary agent is omitted, and 50 parts by mass of water is added and stirred evenly to obtain a hydrophilic resin.

[0082] In S2, the grafted modified polymer is replaced with an equal amount of hydrophobic resin, and a comparative sample is obtained after the configuration is completed.

[0083] Comparative Example 3

[0084] In this comparative example, the specific implementation is similar to that of Example 1, except that: in S2, the graft-modified polymer is 20 parts by mass and water is 72 parts by mass.

[0085] Comparative Example 4

[0086] In this comparative example, the specific implementation is similar to that of Example 1, except that: in S2, the graft-modified polymer is 60 parts by mass and water is 32 parts by mass.

[0087] Performance Testing

[0088] The frost-retarding coatings of Examples 1-8 were applied to fins to form coatings, and the coatings were tested for adhesion, water drop slow-fall time, and water drop sliding time after water flushing. The test results are entered in Table 1. Test method:

[0089] Adhesion: tested by the 100-grid method;

[0090] Water droplet falling time: Place an aluminum plate coated with the anti-frost coating vertically. Use a 10μL dropper to take an 8μL water droplet and drop it onto the coating from the same height. Record the time it takes for the water droplet to slide 8cm. It is generally believed that if the sliding time exceeds 15s, the anti-frost performance does not meet the requirements.

[0091] Water drop sliding time after water flushing: Place the coating in running water and flush for 100 hours, then take it out and test its water drop sliding time.

[0092] In addition, a simulation experimental device was prepared. The refrigeration panel 1 simulated the outdoor low temperature environment. a was the frost-retarding coating sample of Example 1, and b was the hydrophilic sample of Comparative Example 1. The purpose was to observe the external manifestation of liquid drops sliding off the sample.

[0093] Table 1

[0094] As shown in Figure 2, under simulated outdoor low-temperature conditions, water droplets of equal mass were dropped onto plates A and B. After the water droplets slid down due to gravity, it was clearly observed that the frost-retarding coating sample (a) had almost no water marks left, while the hydrophilic sample (b) had obvious water marks. This indicates that the sample of Example 1 was less likely to form frost than the sample of Comparative Example 1.

[0095] As shown in Figure 3, during the simulated freezing and thawing process, sample a initially forms small water droplets, resulting in a distinct, uneven appearance under microscopic observation. Sample b quickly forms a water film, resulting in a uniform, smooth appearance when viewed from below. After thawing, sample a, lacking a water film, quickly forms droplets and slides off without leaving any residue on the substrate. Sample b, however, retains the water film for a long time after thawing due to the barrier effect of the water film. This phenomenon suggests that during continuous air conditioning operation, sample a, due to the rapid removal of droplets, can maintain normal operation without frost, while sample b, due to the barrier effect of the water film, will accumulate and eventually form a thick frost layer, impacting normal operation. This demonstrates that anti-frost coatings can help mitigate the frequency of frost at low temperatures (around 0°C).

[0096] The test results of Examples 1-3 and Example 6 in Table 1 show that when the mass of polyvinylidene fluoride in the hydrophobic polymer accounts for 10-40% of the mass of the hydrophobic polymer, the initial water droplet rolloff time and the time after water flushing are both less than 10 seconds, indicating excellent frosting delay performance. When the mass of polyvinylidene fluoride in the hydrophobic polymer accounts for less than 10-40%, the water droplet rolloff time after water flushing is greater than 20 seconds, indicating lower frosting delay performance than Examples 1 and 2.

[0097] The test results of Examples 1 and 4-5 show that when the mass of the acrylic acid monomer in the hydrophilic polymer is 50% to 80% of the mass of the hydrophilic polymer, the water droplet rolls off quickly, meeting the requirements. When the mass of the acrylic acid monomer in the hydrophilic polymer is not between 50% and 80%, the water droplet rolls off too long after flushing, and the frosting delay capability is lower than that of Example 1.

[0098] It can be seen from the test results of Examples 1-2 and Comparative Examples 1-2 that in the frost-retarding coating, if only hydrophilic polymers are used, the time for water droplets to slide off in the initial stage and after water flushing cannot meet the requirements; if only hydrophobic polymers are used, the time for water droplets to slide off in the initial stage and after water flushing cannot meet the requirements; only when the hydrophilic polymers are combined with the hydrophobic polymers, the time for water droplets to slide off in the initial stage and after water flushing can meet the requirements.

[0099] The test results of Example 1, Examples 7-8, and Comparative Examples 3-4 show that when the content of the grafted modified polymer in the frost-retarding coating is between 30% and 50%, the water droplet roll-off time meets the requirements. When the content is less than 30% or greater than 50%, the water droplet roll-off time after water flushing is greater than 25 seconds, and the frost-retarding performance fails to meet the requirements.

[0100] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. However, such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention and are intended to be included within the scope of protection of the present invention.

Claims

1. A coating material for delaying frosting, characterized in that, Based on the mass of the coating for delaying frosting being 100%, it includes the following components in mass percentage: 30% - 50% of graft-modified polymer, 1% - 15% of functional additives, and the balance being the first solvent; the graft-modified polymer is a polymer prepared by mixing reactants, and the reactants include a hydrophilic polymer, a hydrophobic polymer, a graft-modifying additive, and a second solvent.

2. The coating material for delaying frosting according to claim 1, characterized in that, The hydrophilic polymer is obtained by copolymerizing at least one monomer selected from amide monomers and sulfonic acid monomers with an acrylic acid monomer, and the mass of the acrylic acid monomer is 50% to 80% of the mass of the hydrophilic polymer; the structural formula of the hydrophilic polymer is shown in Formula 1, In formula I, a, b, c, d, e are not all 0, and f is an integer greater than 0.

3. The coating material for delaying frosting according to claim 1, characterized in that, The hydrophobic polymer is obtained by copolymerizing at least one monomer selected from vinyl monomers and organosilicon monomers with a fluorinated monomer, the mass of the fluorinated monomer is 10% - 40% of the mass of the hydrophobic polymer, and the fluorine content of the fluorinated monomer is 20% - 70%.

4. The coating material for delaying frosting according to claim 1, characterized in that, The graft-modifying additive includes at least one of a silane coupling agent and a titanate coupling agent, the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane and vinyltriethoxysilane; the titanate coupling agent includes an oxoacetoxy chelating type titanate coupling agent.

5. The coating material for delaying frosting according to claim 1, characterized in that, The mass of the hydrophilic polymer is 20% - 50% of the mass of the graft-modified polymer, the hydrophobic polymer is 10% - 30% of the mass of the graft-modified polymer, the graft-modifying additive is 0.1% - 5% of the mass of the graft-modified polymer, and the second solvent includes water.

6. The coating material for the frost-delay coating according to claim 1, characterized in that, The first solvent includes an organic solvent and water, and the mass of the organic solvent is 0.1% - 5% of the mass of the coating for delaying frosting.

7. The coating material for the delayed frosting coating according to claim 6, characterized in that, The organic solvent includes an alcohol solvent and / or an ether solvent, the alcohol solvent includes one or more of ethanol, isopropanol, and butanol, and the ether solvent includes one or more of ethylene glycol monoethyl ether and ethylene glycol tert-butyl ether.

8. The coating material for the frosting delay coating according to claim 1, characterized in that, The functional additives include one or more of a curing agent, an antifoaming agent, a wetting agent, and a rheology aid; The curing agent includes at least one of a polyisocyanate compound and a cyanamide compound; The antifoaming agent includes at least one of an organosilicon compound and a mineral oil; The wetting agent includes at least one of a siloxane compound and a fluorocarbon compound; The rheology aid includes a polyurethane associative compound.

9. A method for preparing a coating material for a frosting-delay coating as described in any one of claims 1-8, characterized in that, It includes the following steps: Dissolve the hydrophilic polymer in the second solvent, and then sequentially add the hydrophobic polymer and the graft-modifying additive to the hydrophilic polymer, and react to obtain the graft-modified polymer; Dissolve 1% - 15% of the functional additives in the first solvent, and then add 30% - 50% of the graft-modified polymer to the functional additives, and stir to obtain the coating for delaying frosting.

10. Application of the coating for delaying frosting according to any one of claims 1 - 8 in the field of surface treatment of fins of an air-conditioning heat exchanger.

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