High-light-transmittance anti-melting hydrogel coating for ice and snow structure and preparation method of high-light-transmittance anti-melting hydrogel coating

Abstract

The invention discloses a high-light-transmittance anti-melting hydrogel coating for an ice and snow structure and a preparation method thereof. The coating is based on an environment-degradable polyvinyl alcohol hydrogel system, a continuous protective layer is formed on the surface of an ice and snow matrix through physical-chemical double crosslinking, and the buffer and delay effects on interface moisture migration and energy exchange are achieved, so that sublimation and ablation of ice and snow are effectively slowed down under the environment conditions of temperature rise, wind erosion, heat radiation and the like. The hydrogel system has good wetting spreadability, transparency and film-forming uniformity, can be quickly constructed in a spraying manner, and has the characteristics of humidity regulation, moisture buffering and passive temperature regulation. Compared with the existing protection means depending on refrigeration or frequent manual maintenance, the invention provides a passive anti-melting scheme which is environment-friendly, low in energy consumption and suitable for protecting ice sculptures, snow sculptures and related ice and snow products.

Description

Technical Field

[0001] This invention relates to the field of ice and snow material protection technology, specifically to a high-transmittance, melt-resistant hydrogel coating for ice and snow structures and its preparation method. Background Technology

[0002] Ice and snow, as a unique natural material, possess distinctive visual effects and cultural value in artistic creation and landscape display. However, limited by their inherent physical properties, ice and snow materials exhibit poor stability, a short lifespan, and high sensitivity to the external environment. This has become a critical issue commonly faced by ice sculptures, snow sculptures, and other ice and snow art pieces in practical applications. Ice and snow works are typically extremely sensitive to environmental factors; fluctuations in ambient temperature are the primary cause of ice and snow melting. In spring or during day-night cycles, short-term warming can significantly accelerate the melting rate of ice and snow surfaces. Simultaneously, wind, changes in air humidity, and solar radiation further accelerate the heat exchange process of ice and snow materials, leading to surface structural deterioration and a decrease in overall stability. Furthermore, during long-term service, the surface of ice and snow products also faces a high risk of physical damage. Ice and snow materials are inherently brittle, with a fine surface structure; external forces such as dust adhesion can cause surface wear and detail collapse, affecting artistic expression and aesthetic value.

[0003] With the continuous development of the ice and snow culture industry, ice sculptures, snow sculptures, and related ice and snow landscapes are increasingly widely used in cultural and tourism activities. Extending their display period and improving operational stability are extremely important for boosting the ice and snow economy. However, existing protective measures for ice and snow products still have significant limitations. Currently, common protective methods mainly include active maintenance measures such as regularly spraying water and manually repairing damaged areas, typically used to compensate for surface damage caused during the display of ice and snow products. However, these methods heavily rely on frequent manual operation, resulting in high maintenance costs and difficulty in providing effective protection in situations of rapid temperature increases or large-scale damage. Another common type of passive maintenance method is the installation of refrigeration systems in ice and snow display areas. While these passive defense measures can slow down the melting of ice and snow, they are energy-intensive, require significant equipment investment, and are limited by site power supply conditions and spatial layout, making widespread application difficult.

[0004] Based on the aforementioned problems, it is necessary to propose a new technology for protecting snow and ice products. This technology requires no frequent manual operation or continuous energy supply and can be applied to the surface of snow and ice products as a passive protection method. The coating has heat insulation and moisture retention properties, effectively delaying snow and ice melting when ambient temperatures rise, and reducing damage to the surface from wind erosion and sublimation during long-term service. Simultaneously, this protection method is economical, easy to deploy, bio-friendly, and has high light transmittance, making it more suitable for outdoor snow and ice products. Summary of the Invention

[0005] Based on the above background, the purpose of this invention is to provide a high-transmittance, melt-resistant hydrogel coating for ice and snow structures and its preparation method. This hydrogel system possesses excellent sprayability, enabling it to rapidly form a highly transparent film at low temperatures and adhere tightly to the surface of the ice and snow substrate. In heated environments, through thermal regulation, it can effectively reduce the melting rate of the ice and snow substrate, achieving a melt-resistant effect. During long-term service, through structural action, it can effectively reduce sublimation and minimize wind erosion damage to the ice and snow substrate, thus providing protection. Simultaneously, this protective method also possesses the advantages of being economical, easy to deploy, bio-friendly, and highly transparent.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-transmittance, melt-resistant hydrogel coating for ice and snow structures is prepared by mixing water, polyvinyl alcohol, crosslinking agent, surfactant, defoamer, transmittance regulator, solidification temperature and viscosity regulator in a mass ratio of 100:5~10:0.5~1:1~1.5:0.05~0.5:10~25:5.

[0008] Furthermore, the polyvinyl alcohol is a type with high degree of polymerization and high degree of alcoholysis, such as PVA 1799 or PVA2499; the crosslinking agent is boric acid or borate crosslinking agent, such as boric acid or borax (Na2B4O7).

[0009] Furthermore, the surfactant is a nonionic surfactant, preferably a polyether-type nonionic surfactant such as Pluronic F68 or Pluronic F127; a polyol ester or sorbitol ester surfactant such as Span 20, Span 40, PEG-200, PEG-400, or Tween 80; or a glycosyl surfactant such as APG 0810 or APG 1214.

[0010] Furthermore, the defoamer is a polyether-modified silicone defoamer, such as Silfoam SC-113 or Foamex 805; a non-silicone polyether defoamer, such as Pluronic L61 or Pluronic L64; or an organophosphate defoamer, such as TBP.

[0011] Furthermore, the transmittance modifier is an organic alcohol, specifically glycerol.

[0012] Furthermore, the solidification temperature and viscosity modifier is a low molecular weight alcohol, preferably ethanol or ethylene glycol.

[0013] A method for preparing the above-mentioned high-transmittance, melt-resistant hydrogel coating for ice and snow structures, wherein the method comprises:

[0014] Step 1: Under high temperature conditions, thoroughly stir water, polyvinyl alcohol, surfactant, defoamer, and light transmittance regulator until completely dissolved to obtain a mixture;

[0015] Step 2: Cool the mixture to room temperature, then add the solidification temperature and viscosity modifiers and stir thoroughly.

[0016] Step 3: The above solution is subjected to vacuum degassing treatment to obtain a hydrogel storage solution. The hydrogel storage solution is a stable aqueous phase system that has not undergone cross-linking reaction and is suitable for long-term storage at room temperature and in the dark.

[0017] Step 4: Add a cross-linking agent to the hydrogel storage solution to obtain the hydrogel precursor solution;

[0018] Step 5: Using an airless spraying device, the hydrogel precursor liquid is sprayed onto the ice substrate in a low-temperature environment to obtain a coating.

[0019] Furthermore, in step one, the water used is deionized water, the high temperature is 75~95℃, and the stirring time is 0.5~3h, preferably 1h.

[0020] Furthermore, in step five, the airless spraying equipment uses a spraying pressure of 0.3~0.7MPa, the spraying process uses a distance of 10~30cm between the spray gun and the substrate, a spraying speed of 0.5~5cm / s, and an ambient temperature suitable for operation of -5℃~-20℃.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) This invention proposes and constructs a special anti-melt and life-extending coating system for ice and snow structures for the first time. By forming a dense hydrogel film on the surface of the ice and snow substrate, the interfacial heat conduction and moisture migration processes are precisely controlled. Under the premise of no external energy supply, the melting rate of ice and snow products can be significantly suppressed. It belongs to a passive high-performance heat insulation and protection coating. Compared with traditional ice and snow protection methods, this invention has the core advantages of extremely low energy consumption, flexible deployment, and low preparation and application costs, and its practicality and economy are outstanding.

[0023] (2) This invention uses water-soluble polyvinyl alcohol as the main coating material. The raw material has excellent environmental compatibility and can be degraded stepwise in the natural environment through physical, chemical or biological pathways. After the ice and snow structure is removed, no difficult-to-recycle solid waste residue will be generated. Compared with traditional polymer protective coatings, this invention has better environmental protection properties and is especially suitable for public display scenarios, which can significantly reduce the potential safety and pollution risks to on-site personnel and the surrounding environment.

[0024] (3) By adjusting the ratio of organic alcohols in the hydrogel system, this invention can effectively weaken the light scattering effect at the microscale, enabling the coating to maintain excellent light transmittance even in low-temperature service environments. Compared to conventional translucent hydrogel coatings, this invention is specifically optimized for low-temperature applications of ice and snow products. In low-temperature applications, it can completely preserve the original details and texture of the ice and snow substrate, and can be coordinated with colored lights without compromising the artistic effect of ice and snow works. Attached Figure Description

[0025] Figure 1 This is a flowchart illustrating the preparation method of the hydrogel anti-melt protective coating according to an embodiment of the present invention.

[0026] Figure 2 This is an actual effect diagram of the hydrogel anti-melt protective coating of the present invention on an ice substrate, corresponding to level 1 of the film transmittance test score.

[0027] Figure 3 These are comparative surface morphology images of the hydrogel anti-melt protective coatings of Example 3 and Comparative Example 2 of the present invention, wherein (a) is the hydrogel anti-melt protective coating of Example 3 and (b) is the hydrogel anti-melt protective coating of Comparative Example 2, which correspond to level 3 and level 5 of the film transmittance test score, respectively. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0029] The coating of this invention is based on an environmentally degradable polyvinyl alcohol hydrogel system. Through physical-chemical dual cross-linking, it forms a continuous protective layer on the surface of an ice and snow substrate, buffering and delaying interfacial moisture migration and energy exchange. This effectively slows down the sublimation and melting of ice and snow under environmental conditions such as warming, wind erosion, and thermal radiation. The hydrogel system exhibits good wetting and spreading properties, transparency, and film uniformity. It can be quickly applied by spraying and possesses humidity regulation, moisture buffering, and passive temperature regulation characteristics. Compared with existing protective methods that rely on refrigeration or frequent manual maintenance, this invention provides an environmentally friendly, low-energy-consumption, and passive melt-proof solution suitable for protecting ice sculptures, snow sculptures, and related ice and snow products.

[0030] Example 1

[0031] Take 100g water, 5g polyvinyl alcohol (PVA1799), 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 10g glycerol, and 5g anhydrous ethanol.

[0032] Step 1: Dissolve water, polyvinyl alcohol monomer, Tween 80, tributyl phosphate, and glycerol in a water bath at 75°C.

[0033] Step 2: Cool the polyvinyl alcohol aqueous solution to 20°C, then add anhydrous ethanol and stir thoroughly.

[0034] Step 3: The above solution is subjected to vacuum degassing treatment to obtain a hydrogel storage solution. The hydrogel storage solution is a stable aqueous phase system that has not undergone cross-linking reaction and can be stored at 20°C in the dark for more than one year.

[0035] Step 4: Before the spraying process, add a crosslinking agent to the hydrogel storage solution to obtain a sprayable hydrogel precursor solution.

[0036] Step 5: Use airless spraying equipment, spraying pressure 0.5MPa, spray gun distance 30cm from substrate, spraying speed 1cm / s, and spray onto ice substrate at -20℃.

[0037] Practical Example 2

[0038] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 7.5g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 10g glycerol, and 5g anhydrous ethanol.

[0039] Example 3

[0040] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 10g glycerol, and 5g anhydrous ethanol.

[0041] Actual Example 4

[0042] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 15g glycerol, and 5g anhydrous ethanol.

[0043] Example 5

[0044] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 20g glycerol, and 5g anhydrous ethanol.

[0045] Example 6

[0046] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 25g glycerol, and 5g anhydrous ethanol.

[0047] Comparative Example 1

[0048] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 15g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 10g glycerol, and 5g anhydrous ethanol.

[0049] Comparative Example 2

[0050] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 5g glycerol, and 5g anhydrous ethanol.

[0051] Comparative Example 3

[0052] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 1g Tween 80, 0.5g tributyl phosphate, 30g glycerol, and 5g anhydrous ethanol.

[0053] Comparative Example 4

[0054] The difference between this embodiment and Embodiment 1 is that the raw materials are mixed evenly according to the following ratio (mass ratio): 100g water, 10g polyvinyl alcohol 1799, 1g boric acid, 0.5g tributyl phosphate, 10g glycerol, and 5g anhydrous ethanol.

[0055] Performance testing

[0056] 1. Viscosity tests were conducted on Examples 1-3 and Comparative Example 1 to obtain the influence of polyvinyl alcohol monomer content on the viscosity of the hydrogel precursor solution.

[0057] 2. The film transmittance of Examples 3-6 and Comparative Example 2 were tested to obtain the influence of the transmittance modifier on the transmittance of the hydrogel coating.

[0058] 3. Contact angle tests were conducted on Example 3 and Comparative Example 4 respectively to obtain the influence of surfactant on the contact angle of the hydrogel precursor liquid-ice interface.

[0059] 4. The relative mass loss rate of Example 3 was tested after 48 hours of heating to obtain the anti-melt and life extension effect of the hydrogel coating on the ice substrate under heating environment.

[0060] The specific experimental results and experimental procedures are detailed below.

[0061] 1. Viscosity tests were performed on Examples 1-3 and Comparative Example 1, and the results are shown in Table 1.

[0062] Viscosity testing was conducted using a Forte 4 viscometer according to GB / T 1723-93-T, the method for determining the viscosity of coatings. The coating to be tested was thoroughly stirred and allowed to stand to defoam. After blocking the outlet of the Forte 4 cup, the coating was filled to the top of the cup and the surface was leveled. The outlet was then quickly opened, and timing was started simultaneously. The time taken from the point where the coating flowed continuously until the first interruption occurred was recorded. This flow time is the Forte 4 cup viscosity value of the coating.

[0063] Table 1

[0064]

[0065] As can be seen from the results in Table 1, polyvinyl alcohol has a significant impact on the viscosity of the hydrogel solution. The viscosities of Examples 1-3 are all at the minimum required for spraying using a spray gun, thus meeting the most basic operational requirements.

[0066] 2. Film transmittance tests were conducted on Examples 3-6 and Comparative Example 2: Different forms of ice appearing on the coating surface were observed and recorded. The evaluation indicators are shown in Table 2, and the results are shown in Table 3.

[0067] Table 2

[0068]

[0069] Table 3

[0070]

[0071] Table 3 shows that the whitening degree of the hydrogel film can be effectively improved with the concentration of glycerol, but the improvement is limited and cannot completely prevent the whitening phenomenon. The multi-scale structural inhomogeneity caused by microcrystallization during film formation and freezing is a process determined by both thermodynamics and kinetics. Glycerol can only delay this process by increasing the system's flexibility, but it cannot fundamentally eliminate the formation of phase separation and optical scattering structures.

[0072] 3. Contact angle tests were conducted on Example 3 and Comparative Example 4, and the results are shown in Table 4:

[0073] The contact angle test involves preparing a flat and clean ice substrate, adding an equal volume of hydrogel precursor liquid droplets to the ice surface using a pipette, allowing the droplets to stand until their morphology stabilizes, and then taking a picture of the side of the droplets. The obtained droplet side view image is imported into analysis software, and the angle between the droplet and the tangent on the ice surface is calculated by fitting the contour near the droplet-ice interface to obtain the static contact angle value.

[0074] Table 4

[0075]

[0076] As shown in Table 4, adding an appropriate amount of nonionic surfactant can significantly reduce the contact angle of the hydrogel precursor liquid on the ice surface, improve the wetting and spreading ability and the interfacial contact area, which is beneficial to the uniform film formation and initial interfacial stability of the coating.

[0077] 4. The relative mass loss rate of Example 3 was tested after 48 hours of heating, and the results are shown in Table 5:

[0078] In the experiment, a 100mm×100mm×20mm rectangular ice block was used as the ice substrate. Hydrogel was applied to the two larger sides of the ice substrate. The temperature was raised outdoors, with the temperature fluctuating from -5℃ to 7℃ on the first day and from -7℃ to 7℃ on the second day. The influence of sunlight was distinguished by whether or not the ice block was placed in a dark box. The mass of the test block was recorded after 48 hours. The relative mass loss rate was obtained by dividing the mass loss of Example 3 by the mass loss of the ice substrate without hydrogel film coverage.

[0079] Table 5

[0080]

[0081] As shown in Table 5, under conditions without sunlight, the hydrogel exhibits a higher rate of mass loss retardation. This is because the energy input to the ice and snow substrate mainly comes from conduction and convection heat transfer caused by the increase in ambient temperature. The hydrogel film, through its high water content and continuous coverage structure, buffers and delays interfacial heat transfer and moisture diffusion, thereby effectively reducing the melting and sublimation rate of the ice. In contrast, under sunlight conditions, solar radiation becomes the main energy input pathway. Radiant energy can directly act on the coating surface and rapidly convert into heat in localized areas. Since the hydrogel film itself has limited shielding and reflection capabilities against short-wave radiation, radiant heat leads to an increase in surface temperature, thus weakening the passive protection effect of the coating through humidity regulation and thermal buffering.

Claims

1. A high-transmittance, melt-resistant hydrogel coating for ice and snow structures, characterized in that: The hydrogel coating is prepared by mixing water, polyvinyl alcohol, crosslinking agent, surfactant, defoamer, light transmittance regulator, solidification temperature and viscosity regulator in a mass ratio of 100:5~10:0.5~1:1~1.5:0.05~0.5:10~25:

5.

2. The hydrogel coating according to claim 1, characterized in that: The polyvinyl alcohol is PVA 1799 or PVA 2499; the crosslinking agent is boric acid or a borate crosslinking agent.

3. The hydrogel coating according to claim 1, characterized in that: The surfactant is a nonionic surfactant.

4. The hydrogel coating according to claim 1, characterized in that: The defoamer is one of the following: polyether-modified silicone defoamer, non-silicone polyether defoamer, or organophosphate defoamer.

5. The hydrogel coating according to claim 1, characterized in that: The light transmittance modifier is an organic alcohol.

6. The hydrogel coating according to claim 1, characterized in that: The solidification temperature and viscosity modifier is a low molecular weight alcohol.

7. A method for preparing a high-transmittance, melt-resistant hydrogel coating for ice and snow structures according to any one of claims 1 to 6, characterized in that: The method is as follows: Step 1: Under high temperature conditions, thoroughly stir water, polyvinyl alcohol, surfactant, defoamer, and light transmittance regulator until completely dissolved to obtain a mixture; Step 2: Cool the mixture to room temperature, then add the solidification temperature and viscosity modifiers and stir thoroughly. Step 3: Perform vacuum degassing on the above solution to obtain the hydrogel storage solution; Step 4: Add a cross-linking agent to the hydrogel storage solution to obtain the hydrogel precursor solution; Step 5: Using an airless spraying device, the hydrogel precursor liquid is sprayed onto the ice substrate in a low-temperature environment to obtain a coating.

8. The preparation method according to claim 7, characterized in that: In step one, the high temperature is 75~95℃ and the stirring time is 0.5~3h.

9. The preparation method according to claim 7, characterized in that: In step five, the airless spraying equipment uses a spraying pressure of 0.3~0.7MPa, the spraying process uses a distance of 10~30cm between the spray gun and the substrate, a spraying speed of 0.5~5cm / s, and an ambient temperature suitable for operation of -5℃~-20℃.

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