Flexible phase change cold storage material and preparation method therefor, cold storage agent, and flexible cold storage bag

Abstract

A flexible phase change cold storage material and a preparation method therefor, a cold storage agent, and a flexible cold storage bag, relating to the technical field of heat energy storage. The flexible phase change cold storage material comprises an inorganic salt aqueous solution, a hydrophilic polymer, and a crosslinking degree enhancer, and optionally can also comprise other additives; the hydrophilic polymer is formed by copolymerizing a mixed monomer, a modified nucleating agent, and a crosslinking agent; and the crosslinking degree enhancer is nano silicon dioxide having a particle size of 10 nm to 80 nm. According to the flexible phase change cold storage material, a granular modified nucleating agent is dispersed and modified in a hydrophilic polymer structure, and a crosslinking degree enhancer and a hydrophilic polymer are used to form a double-network interpenetrating conformation, thereby overcoming the problems of low phase change latent heat, easy release of free water, high packaging design requirements and the like in existing inorganic salt flexible phase change cold storage materials, showing high phase change latent heat and high recycling stability, and guaranteeing that photoetching materials can obtain a specific and long-lasting low-temperature environment during storage and transportation.

Description

Flexible phase-change cold storage material and preparation method thereof, cold storage agent, and flexible cold storage bag Technical Field

[0001] The present application relates to the field of thermal energy storage technology, specifically to a flexible phase-change cold storage material and a preparation method thereof, a cold storage agent, and a flexible cold storage bag, and especially to a flexible phase-change cold storage material and a preparation method thereof, a refrigerated cold storage agent, a cold storage agent for storing photolithographic materials, and a flexible cold storage bag. The photolithographic materials include photoresists, anti-reflective coatings, spin-on hard masks, and spin-on glass hard masks used in the photolithographic process. Background Art

[0002] The basic storage methods of thermal energy can be divided into sensible heat storage, latent heat storage, and thermochemical energy storage. Among them, latent heat storage has the advantages of low cost, high energy storage density, stable output temperature and energy compared to the other two methods, and is the focus of research in the current field of energy storage technology. The realization of latent heat storage is based on the phase change process of matter (melting, evaporation, solidification, liquefaction, etc.), so it is also called phase change energy storage. Phase change energy storage can be divided into heat storage and cold storage from the perspective of storage and release energy utilization. Examples of cold storage applications include air conditioning cold storage, building cold storage, cold chain logistics, food preservation, etc. The development of phase change cold storage materials is also an indispensable part of the phase change cold storage field.

[0003] At present, the main energy storage agent of refrigerated phase change cold storage materials (phase change temperature below 0°C) is generally an inorganic salt solution. Its phase change cold storage density is high, the phase change temperature adjustment space is large, the preparation process is simple, and the cost is low. It is widely used in cold chain transportation of food, medicine, biological preparations, etc. However, the volume of the inorganic salt solution changes greatly during the phase change process. In order to avoid leakage, the requirements for the packaging material are relatively stringent.

[0004] Compared to solutions focused on packaging container design, the preparation of phase-change gels not only offers advantages such as simple process, ease of scalability, and high reliability, but more importantly, the use of hydrophilic polymers can increase the viscosity of the inorganic salt aqueous solution, thereby resolving the phase separation problem. Despite the numerous advantages of inorganic salt phase-change gels based on hydrophilic polymers, most currently available hydrophilic polymers are characterized by low internal cross-linking and limited rigidity. This results in a loose morphology and a tendency for irreversible free water precipitation after repeated temperature changes or under low external forces, resulting in poor cyclic stability of the cool storage gels. Furthermore, hydrophilic polymers primarily absorb and lock in water molecules by ionizing, stretching the polymer chains. However, this process disrupts some hydrogen bonds between water molecules, thereby reducing the latent heat of phase change in the inorganic salt aqueous solution. Furthermore, since hydrophilic polymers form gels when combined with inorganic salt aqueous solutions, when granular inorganic nucleating agents are used to reduce the supercooling of the inorganic salt aqueous solution phase change coolant, the nucleating agents with poor water solubility are difficult to disperse in the gel, resulting in the inability to exert the nucleating effect.

[0005] Based on this, it is necessary to develop a cold storage gel with better cold storage effect, longer service life and better risk resistance.

[0006] Summary of the Invention

[0007] To solve the above problems, this application fully studies the swelling behavior of the composite cold storage material in inorganic salt solution, the precipitation of free water after cyclic heating and cooling, and its flexibility changes, etc., aiming to provide a flexible phase change cold storage material with more stable cold storage performance, stronger cold storage capacity and lower leakage risk.

[0008] One of the purposes of the present application is to provide a flexible phase-change cold storage material, which has high phase-change latent heat, long-lasting stability, flexible shaping effect, low phase-change temperature, and is suitable for low-temperature storage and transportation of photolithography materials; another purpose of the present application is to provide a preparation method of a flexible phase-change cold storage material, which is simple to operate and can be used to prepare a flexible phase-change cold storage material with high phase-change latent heat, long-lasting stability, flexible shaping effect, and low phase-change temperature; another purpose of the present application is to provide a refrigerated cold storage agent, which has a relatively stable phase-change temperature; another purpose of the present application is to provide a cold storage agent for the storage of photolithography materials; it can avoid the chemically active groups of the photolithography material from reacting during storage and transportation; another purpose of the present application is to provide a flexible cold storage bag, which has high cold storage density, good cycle stability, and flexible deformation, and can be flexibly filled around the object to be stored and transported at low temperature according to specific needs.

[0009] In a first aspect of the present application, a flexible phase-change cold storage material is provided, which comprises, by weight percentage:

[0010] The inorganic salt aqueous solution comprises an inorganic salt and water, wherein the weight of the inorganic salt accounts for 3% to 40% of the total weight of the inorganic salt aqueous solution;

[0011] The hydrophilic polymer is copolymerized by a mixed monomer, a modified nucleating agent and a crosslinking agent; the mixed monomer includes an acrylic acid compound, an acrylate compound and an acrylamide compound in a molar ratio of 1:(3-8):(0.05-0.5); the modified nucleating agent is a product obtained by surface modification of the nucleating agent with functional groups using a silane coupling agent, wherein the modified groups account for 0.5% to 5% of the total weight of the modified nucleating agent;

[0012] The cross-linking enhancer is nano-silicon dioxide with a particle size of 10nm to 80nm;

[0013] The other additives include corrosion inhibitors.

[0014] In some embodiments, the modified nucleating agent is chemically bonded to the main chain or side chain of the hydrophilic polymer.

[0015] In some embodiments, the weight of the modified nucleating agent is 0.05% to 0.5% of the total weight of the mixed monomers;

[0016] The molar addition amount of the cross-linking agent relative to the acrylic compound is 0.05% to 0.5%.

[0017] In some embodiments, the flexible phase-change cold storage material has at least one of the following technical features:

[0018] (1) The acrylic compound is selected from at least one of acrylic acid and methacrylic acid;

[0019] (2) the acrylate compound is at least one selected from the group consisting of sodium acrylate, potassium acrylate, sodium methacrylate, and potassium methacrylate;

[0020] (3) the acrylamide compound is selected from at least one of acrylamide and methacrylamide;

[0021] (4) the cross-linking agent is selected from at least one of ethylene glycol diglycidyl ether, N,N'-methylenebispropionamide, N-vinyl-2-pyrrolidone and ethylene glycol diacrylate;

[0022] (5) The nucleating agent is selected from at least one of nano zinc oxide, nano aluminum oxide, nano silicon carbide and carbon nanotubes;

[0023] (6) The corrosion inhibitor is selected from at least one of nitrite, chromate, phosphate, silicate and benzoate.

[0024] A second aspect of the present application provides a method for preparing a flexible phase-change cold storage material, comprising the following steps:

[0025] Prepare the raw materials according to the formula of the flexible phase change cold storage material provided in the first aspect of the present application;

[0026] Taking the inorganic salt aqueous solution, optionally adding the other additives and mixing to prepare a first solution;

[0027] Under first dispersion conditions, adding the hydrophilic polymer to the first solution and mixing to prepare a first gel;

[0028] Under the second dispersion condition, the cross-linking enhancer is added to the first gel.

[0029] In some embodiments, the hydrophilic polymer is prepared by emulsion polymerization;

[0030] The modified nucleating agent is added during the emulsion polymerization process to carry out copolymerization.

[0031] In some embodiments, the modified nucleating agent is prepared by the steps comprising the following preparation method:

[0032] The nucleating agent is dispersed in an organic solvent, a silane coupling agent is added and mixed, ultrasonicated, and heated to 80° C. to 90° C. for reaction.

[0033] In some embodiments, the preparation method has at least one of the following preparation conditions:

[0034] (1) The first dispersion condition includes: stirring at 30 rpm to 100 rpm;

[0035] (2) The second dispersion condition includes: stirring at 30 rpm to 100 rpm;

[0036] (3) The first dispersion time is 0.5 h to 2 h;

[0037] (4) The second dispersion time is 0.5h to 3.5h.

[0038] The third aspect of the present application provides a refrigeration-type cold storage agent containing the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application.

[0039] The fourth aspect of the present application provides a cold storage agent for storing photolithographic materials, which contains the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application.

[0040] In some embodiments, the photoresist material is stored in a coolant, and the photoresist material includes a photoresist, an anti-reflective coating, a spin-on carbon hard mask, and a spin-on glass hard mask.

[0041] In a fifth aspect of the present application, there is provided a flexible cold storage pack comprising a sealed package and a cold storage agent filled in the sealed package;

[0042] The cold storage agent contains the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application.

[0043] The flexible phase change cold storage material provided in the present application overcomes the problems of existing inorganic salt phase change cold storage gels, such as low phase change latent heat, easy release of free water, difficult dispersion of granular nucleating agents, and high packaging design requirements, by dispersing a granular modified nucleating agent in a hydrophilic polymer structure and using a cross-linking enhancer to form a double network interpenetrating conformation with the hydrophilic polymer. It exhibits high phase change latent heat and high cycle stability, and can ensure that the photolithography material can obtain a specific and long-lasting low-temperature environment during storage and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 is a comparison of the flexible shaping effects of the phase-change cool storage gels of Example 1 and Comparative Example 1 of the present application. A in Figure 1 is the phase-change cool storage gel prepared in Example 1, and B in Figure 1 is the phase-change cool storage gel prepared in Comparative Example 1. DETAILED DESCRIPTION

[0046] The present application will be further described below in conjunction with the embodiments, examples and accompanying drawings. It should be understood that these examples are intended only to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the content taught in this application, those skilled in the art may make various changes or modifications to the present application, and these equivalent forms also fall within the scope of protection of the claims appended hereto.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0048] the term

[0049] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0050] Herein, "preferred", "better", "better", etc. are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of this application.

[0051] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0052] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0053] In this application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is considered continuous and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every numerical value between the two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0054] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0055] In this application, weight may be μg, mg, g, kg or other weight units known in the chemical industry.

[0056] In this application, unless otherwise specified, the size, particle size, and diameter generally refer to the average value.

[0057] In this application, the terms "first", "second", "third", "fourth", "fifth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", "the fifth aspect", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor should they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", "fifth", etc. only serve the purpose of non-exhaustive enumeration and description, and should be understood not to constitute a closed limitation on quantity.

[0058] In the first aspect of the present application, a flexible phase-change cold storage material is provided, which comprises an appropriate amount of an inorganic salt aqueous solution, a hydrophilic polymer and a cross-linking enhancer, and may optionally further comprise other additives. The components interact with each other to give the material high phase change latent heat performance, long-lasting stability and flexible shaping effect.

[0059] In some embodiments, the flexible phase change cold storage material has at least one of the following characteristics:

[0060] (1) The latent heat of phase change is 230kJ / kg to 300kJ / kg;

[0061] (2) Phase transition temperature is -15℃~-5℃;

[0062] (3) The absolute value of supercooling is 0.5℃~1.5℃;

[0063] (4) The total content of the non-latent heat functional components may be 0.5% to 20%.

[0064] The flexible phase-change cold storage material of the present application may have a phase-change latent heat value greater than 230 kJ / kg, further 230 kJ / kg to 300 kJ / kg, and further 250 kJ / kg to 300 kJ / kg, and has a good cold storage effect. In one embodiment, the phase change latent heat value of the flexible phase change cold storage material is selected from 230kJ / kg to 300kJ / kg, 230kJ / kg to 240kJ / kg, 232kJ / kg to 252kJ / kg, 250kJ / kg to 260kJ / kg, 255kJ / kg to 275kJ / kg, 270kJ / kg to 290kJ / kg, 280kJ / kg to 300kJ / kg, etc., and examples of the phase change latent heat values ​​are 251.35kJ / kg, 251.28kJ / kg, 258.02kJ / kg, 270.19kJ / kg, 236.44kJ / kg, etc.

[0065] The flexible phase-change cold storage material of the present application has a phase-change temperature below 0°C, and can further be -15°C to -5°C. It can be used for the storage and transportation of substances with high chemical activity, such as photolithographic materials.

[0066] In one embodiment, the phase change temperature of the flexible phase change cold storage material is selected from -15°C to -5°C, -15°C to -10°C, -13°C to -10°C, -12°C to -8°C, -10°C to -5°C, etc., and examples of phase change temperatures include -11.81°C, -11.64°C, -10.81°C, -13.11°C, and -9.86°C.

[0067] The flexible phase-change cold storage material of the present application has a low degree of supercooling. The absolute value of the supercooling can be less than 1.5°C, and can further be 0.5°C to 1.5°C. Supercooling refers to the fact that a liquid substance does not crystallize when cooled to its theoretical freezing point, but needs to be cooled below the theoretical freezing point to begin crystallization. The existence of supercooling requires a lower cold source temperature and more energy consumption when the phase-change material is charged with cold. Supercooling is the difference between the theoretical freezing temperature and the actual freezing temperature.

[0068] In one embodiment, the absolute value of the supercooling degree of the flexible phase change cold storage material is selected from 0.5℃~1.5℃, 0.5℃~0.8℃, 0.6℃~0.9℃, 0.8℃~1.2℃, 0.9℃~1.5℃, 1.2℃~1.5℃, etc., and the absolute value of the supercooling degree is exemplified by 0.53℃, 1.02℃, 0.83℃, 0.78℃, 0.69℃, etc.

[0069] The flexible phase-change cold storage material of the present application has a high cold storage density. It can contain a high content of inorganic salt aqueous solution (latent heat functional component) in terms of weight percentage, while the sum of the contents of the remaining non-latent heat functional components can be 0.5% to 20%, and further can be 2% to 10%. In addition, the water absorption effect will not be deteriorated due to the excessive content of the inorganic salt aqueous solution. The flexibility of the material is well maintained during freezing and thawing, and it has excellent cyclic stability.

[0070] The cyclic stability of the flexible phase-change cold storage material of the present application can be reflected according to the number of freezing and thawing cycles and the water retention state and phase change latent heat change value of the material after the freezing and thawing cycles.

[0071] In one embodiment, after 100 cycles of testing, the latent heat change rate of the flexible phase-change cold storage material is less than 3%, and may further be 1% to 3%.

[0072] In one embodiment, after 100 cycles of testing, the flexible phase-change cold storage material has no free water seepage and has good water retention.

[0073] In some preferred embodiments, the flexible phase-change cold storage material has a latent heat value of 250 kJ / kg to 300 kJ / kg, a phase change temperature of -15°C to -10°C, and an absolute value of supercooling of 0.5°C to 1.1°C. Furthermore, after 100 cooling / thawing cycle tests, the phase-change latent heat change rate of the phase-change cold storage gel is less than 3%, and there is no problem of cold storage failure or free water seepage, showing high phase-change latent heat and high cycle stability. The flexible phase-change cold storage material of the present application includes, by weight percentage:

[0074] Furthermore, the inorganic salt aqueous solution comprises an inorganic salt and water, and the weight of the inorganic salt accounts for 3% to 40% of the total weight of the inorganic salt aqueous solution;

[0075] The hydrophilic polymer is copolymerized by a mixed monomer, a modified nucleating agent, and a crosslinking agent; the mixed monomer comprises an acrylic acid compound, an acrylate compound, and an acrylamide monomer in a molar ratio of 1:(3-8):(0.05-0.5); the modified nucleating agent is a product obtained by surface-modifying the nucleating agent with functional groups using a silane coupling agent, wherein the modified groups account for 0.5% to 5% of the total weight of the modified nucleating agent;

[0076] The cross-linking enhancer is nano-silicon dioxide with a particle size of 10nm to 80nm;

[0077] Other additives include corrosion inhibitors.

[0078] Inorganic salt solution

[0079] In one embodiment, the inorganic salt in the inorganic salt aqueous solution can be selected from one or a combination of two or more chlorides; the inorganic salt aqueous solution formed by the chloride has a high phase change latent heat, and the phase change temperature is consistent with the low temperature storage and transportation temperature range (-15°C to -5°C) of the photoresist material containing highly chemically active groups.

[0080] Preferably, the inorganic salt can be selected from one or a combination of two or more of sodium chloride, potassium chloride, ammonium chloride, and barium chloride. In some embodiments, the weight of the inorganic salt accounts for 3% to 40% of the total weight of the inorganic salt aqueous solution; further, the weight of the inorganic salt accounts for 5% to 35% of the total weight of the inorganic salt aqueous solution; further, the weight of the inorganic salt accounts for 8% to 25% of the total weight of the inorganic salt aqueous solution.

[0081] In some embodiments, the weight of the inorganic salt aqueous solution is 80% to 99.5% of the total weight of the flexible phase change cold storage material; further, the weight of the inorganic salt aqueous solution is 82.7% to 99.2% of the total weight of the flexible phase change cold storage material; further, the weight of the inorganic salt aqueous solution is 86.6% to 98.5% of the total weight of the flexible phase change cold storage material.

[0082] In some embodiments, the weight of the inorganic salt aqueous solution is 90% to 95% of the total weight of the flexible phase change cold storage material, and can further be 92% to 94%. Preferably, the inorganic salt is potassium chloride.

[0083] hydrophilic polymers

[0084] Hydrophilic polymers play a crucial role in absorbing water in composite materials. Before absorbing an inorganic salt solution, the polymer chains are close together, forming a generally tight bond. Upon contact with the inorganic salt solution, the polymer chains stretch, allowing water molecules to enter the polymer network, causing the polymer to expand and form a hydrogel.

[0085] In this application, the hydrophilic polymer is copolymerized from a mixed monomer, a modified nucleating agent, and a crosslinking agent. Propionic acid compounds and acrylamide compounds provide active sites for the hydrophilic polymer to form hydrogen bonds with water; acrylate compounds provide active sites for the hydrophilic polymer to ionize in water; and the crosslinking agent provides crosslinking sites for linearly polymerized acrylic acid polymer segments, forming a three-dimensional crosslinked polymer network. The nucleating agent's function includes reducing the degree of supercooling of the inorganic salt solution during cooling. The modified nucleating agent in this application also has the combined effect of improving stability, flexible deformation, and latent heat of phase change.

[0086] In some embodiments, the molar ratio of the acrylic acid compound, the acrylate compound, and the acrylamide compound is 1:(3-8):(0.05-0.5).

[0087] In some embodiments, the molar amount of the cross-linking agent is 0.05% to 0.5% of the molar amount of the acrylic compound.

[0088] Optionally, the acrylic compound is selected from one or a combination of two or more of acrylic acid and methacrylic acid.

[0089] Optionally, the acrylate compound is selected from one or a combination of two or more of sodium acrylate, potassium acrylate, sodium methacrylate, and potassium methacrylate.

[0090] Optionally, the acrylamide compound is selected from one or a combination of two or more of acrylamide and methacrylamide.

[0091] Optionally, the cross-linking agent is selected from one or a combination of two or more of ethylene glycol diglycidyl ether, N,N'-methylenebispropionamide, N-vinyl-2-pyrrolidone, and ethylene glycol diacrylate.

[0092] Furthermore, the modified nucleating agent is chemically connected to the main chain or side chain of the hydrophilic polymer structure. The purpose of connecting the modified nucleating agent to the structure of the hydrophilic polymer is twofold: first, it realizes the pre-dispersion of the granular nucleating agent inside the hydrophilic polymer structure, so that the nucleating agent obtains a more uniform dispersion effect in the low-temperature cold storage gel; second, it realizes a close connection between the hydrophilic resin and the nucleating agent, avoiding the sedimentation of the nucleating agent in the gel system due to repeated melting and freezing of the gel and the agglomeration of the nucleating agent particles.

[0093] In some embodiments, the weight of the modified nucleating agent is 0.05% to 0.5% of the total weight of the mixed monomers.

[0094] In some embodiments, the modified nucleating agent is a product obtained by performing functional group surface modification treatment on the nucleating agent using a silane coupling agent.

[0095] In some embodiments, the weight of the grafted groups in the modified nucleating agent is 0.5% to 5% by weight of the modified nucleating agent.

[0096] In some embodiments, the silane coupling agent is selected from one of KH560 and KH570.

[0097] In some embodiments, the nucleating agent is selected from one or a combination of two or more of nano zinc oxide, nano aluminum oxide, nano silicon carbide, and carbon nanotubes.

[0098] In some embodiments, the weight of the hydrophilic polymer is 0.5% to 10% of the total weight of the flexible phase change cold storage material; further, the weight of the hydrophilic polymer is 1% to 9% of the total weight of the flexible phase change cold storage material; further, the weight of the hydrophilic polymer is 2% to 8% of the total weight of the flexible phase change cold storage material.

[0099] Crosslinking enhancer

[0100] This application uses nano-silica of appropriate particle size as a cross-linking enhancer. The silanol structure on the surface of nano-silica can form a large number of hydrogen bonds with water molecules in the inorganic salt solution, and can also combine with some group structures (such as carboxyl groups) in the hydrophilic polymer in the form of hydrogen bonds, thereby constructing a hydrogen bond network with a certain structural rigidity, which is interspersed with the hydrophilic polymer cross-linking network, further fixing the water molecules in the gel system, thereby reducing the possibility of water molecules in the phase change gel seeping out. The phase change cold storage gel can maintain stable phase change thermal performance during long-term cyclic use, and increase the number of cycles of the phase change cold storage gel.

[0101] The three-dimensional network conformation based on hydrogen bonds formed by nano-silica and water molecules can enhance the binding force between water molecules, thereby repairing the damage to the binding ability between some water molecules in the inorganic salt aqueous solution caused by the addition of hydrophilic polymers, and increasing the phase change latent heat of the phase change gel.

[0102] Nano-silica can form a hydrogen-bonded, structurally rigid silicon hydroxyl-water molecule network interspersed with a hydrophilic polymer network, thereby increasing the binding force between phase-change cool storage gel particles, avoiding the loose binding state between phase-change cool storage gels, and enhancing the flexible solid-phase shaping effect of phase-change cool storage gels.

[0103] When the particle size of nano-silica is less than 10nm, it is more difficult from the perspective of preparation technology and has higher economic costs; when the particle size of nano-silica is greater than 80nm, the nano-silica particle size is larger and the specific surface area is relatively small, making it difficult to achieve an ideal uniform dispersion effect.

[0104] In some embodiments, the particle size of the nano-silica is 10 nm to 80 nm; further, the particle size of the nano-silica is 20 nm to 50 nm.

[0105] In some embodiments, the weight of nano-silica is 0.1% to 5% of the flexible phase-change cold storage material; further, the weight of nano-silica is 0.3% to 3% of the flexible phase-change cold storage material; further, the weight of nano-silica is 0.5% to 3% of the flexible phase-change cold storage material.

[0106] Other additives

[0107] The flexible phase-change cold storage material of the present application may optionally contain a corrosion inhibitor or may not contain a corrosion inhibitor.

[0108] Optionally, the corrosion inhibitor can be selected from any one of nitrites, chromates, phosphates, silicates, and benzoates, or a combination of two or more. When the flexible phase-change cool storage material comes into contact with common metals (e.g., copper, aluminum, steel), the corrosion inhibitor contained therein can slow down the corrosion process of the inorganic salt medium on the metal. For example, if sodium benzoate is selected as a corrosion inhibitor, the corrosion process of the phase-change cool storage gel on metals such as brass and copper can be slowed down; if sodium chromate is selected as a corrosion inhibitor, the corrosion process of the phase-change cool storage gel on steel can be slowed down.

[0109] In some embodiments, the weight of the corrosion inhibitor is 0.1% to 1% of the weight of the inorganic salt aqueous solution in the flexible phase-change cold storage material.

[0110] In some embodiments, the flexible phase-change cold storage material is composed of the following components in the following weight percentages: 80% to 99.5% of an inorganic salt aqueous solution, 0.5% to 10% of a hydrophilic polymer, 0.1% to 5% of a cross-linking enhancer, and 0% to 1% of other additives;

[0111] Furthermore, as long as the total weight percentage of each component is 100%, the weight percentage of the inorganic salt aqueous solution in the flexible cold storage material can be independently selected from 80% to 99.5%, further selected from 92% to 94%, with examples of percentages such as 80%, 92%, 92.54%, 93%, 93.53%, 94%, 99.5%, etc.; the weight percentage of the hydrophilic polymer in the flexible cold storage material can be independently selected from 0.5% to 10%, further selected from 2% to 8%, with examples of percentages such as 0.5%, 2 %, 3%, 4%, 5%, 6%, 7%, 8%, 10%, etc.; the weight percentage of the cross-linking enhancer in the flexible cold storage material can be independently selected from 0.1% to 5%, further selected from 0.5% to 3%, and exemplified by 0.1%, 0.5%, 1%, 2%, 3%, 5%, etc.; the weight percentage of other additives in the flexible cold storage material can be independently selected from 0 to 1%, further selected from 0.4% to 0.5%, and exemplified by 0, 0.4%, 0.46%, 0.47%, 0.5%, 1%, etc.;

[0112] Furthermore, the inorganic salt aqueous solution is selected from at least one of potassium chloride and barium chloride solution; the crosslinking enhancer is selected from at least one of nano-silica with a particle size of 30 nm, nano-silica with a particle size of 80 nm, and carboxymethyl cellulose; in the technical solution in which a sustained-release agent is present, the sustained-release agent is selected from sodium benzoate; and the hydrophilic polymer is selected from the hydrophilic polymers described in any of the above technical solutions.

[0113] In one embodiment, the flexible phase-change cold storage material is composed of the following components in the following weight percentages:

[0114] 18.7% of the inorganic salt, 74.83% of the water, 5% of the hydrophilic polymer, 1% of the crosslinking enhancer and 0.47% of the corrosion inhibitor; or,

[0115] 18.51% of the inorganic salt, 74.03% of the water, 5% of the hydrophilic polymer, 2% of the crosslinking enhancer and 0.46% of the corrosion inhibitor; or,

[0116] 18.7% of the inorganic salt, 74.83% of the water, 4% of the hydrophilic polymer, 2% of the crosslinking enhancer and 0.47% of the corrosion inhibitor; or,

[0117] 9.35% of the inorganic salt, 84.18% of the water, 5% of the hydrophilic polymer, 1% of the cross-linking enhancer and 0.47% of the corrosion inhibitor; or,

[0118] 20.58% of the inorganic salt, 72.95% of the water, 5% of the hydrophilic polymer, 1% of the cross-linking enhancer and 0.47% of the corrosion inhibitor.

[0119] In the second aspect of the present application, a method for preparing a flexible phase-change cold storage gel is provided. The preparation method can be used to prepare the flexible phase-change cold storage material provided in the first aspect of the present application. The flexible phase-change cold storage material has high phase change latent heat and has long-lasting stability and flexible shaping effect.

[0120] In some embodiments, the preparation method of the flexible phase change cold storage material comprises the following steps:

[0121] S100: preparing various raw materials according to the formula of the flexible phase change cold storage material provided in the first aspect of the present application;

[0122] S200: taking an inorganic salt aqueous solution, optionally adding other additives and mixing to prepare a first solution;

[0123] S300: adding a hydrophilic polymer to the first solution under a first dispersion condition and mixing to prepare a first gel;

[0124] S400: adding a cross-linking enhancer to the first gel under the second dispersion condition.

[0125] S100 raw material preparation:

[0126] The characteristics of each raw material are as stated in the first aspect of this application and will not be repeated here.

[0127] In some embodiments, the modified nucleating agent is prepared by the following steps: dispersing the nucleating agent in an organic solvent, adding a silane coupling agent, mixing, ultrasonicating, and heating to 80° C. to 90° C. for reaction.

[0128] In some embodiments, the hydrophilic polymer is prepared by emulsion polymerization; a modified nucleating agent is added during the emulsion polymerization process for copolymerization. The hydrophilic polymer prepared by this preparation method has the nucleating agent chemically bonded to the main chain or side chains of the structure, allowing the nucleating agent to be pre-dispersed within the hydrophilic polymer structure. Furthermore, the nucleating agent and the hydrophilic polymer are chemically bonded, thereby preventing sedimentation and aggregation of the nucleating agent in the gel due to repeated freeze-thaw cycles.

[0129] In some embodiments, the first dispersion conditions include: stirring at 30 r / min to 100 r / min, and further can be 30 r / min to 80 r / min. Example stirring speeds are 30 r / min, 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, etc.

[0130] In some embodiments, the first dispersion time is 0.5 h to 2 h, and examples of the first dispersion time include 0.5 h, 1 h, 1.5 h, and 2 h.

[0131] In some embodiments, the second dispersion conditions include: stirring at 30 r / min to 100 r / min, and further can be 30 r / min to 80 r / min. Example stirring speeds are 30 r / min, 40 r / min, 50 r / min, 60 r / min, 70 r / min, 80 r / min, etc.

[0132] In some embodiments, the second dispersion time is 0.5 h to 3.5 h, and examples of the second dispersion time are 0.5 h, 1.5 h, 2.5 h, 3.5 h, etc.

[0133] In some embodiments, the hydrophilic polymer is prepared by the following preparation steps:

[0134] An aqueous acrylic acid solution is placed in a reaction container, and an alkali solution is added dropwise to the reaction container under mechanical stirring while the reaction container is externally ice-cooled, thereby obtaining a mixed solution having a molar ratio of acrylic acid to acrylate of 1:(3-8), and then an aqueous acrylamide solution and an initiator are added to prepare a mixed monomer solution having a molar ratio of acrylic acid compound, acrylate monocompound, and acrylamide monomer of 1:(3-8):(0.05-0.5);

[0135] The modified nano-alumina is dispersed in n-heptane at high speed to form a modified nano-alumina suspension;

[0136] Take n-heptane and ethyl cellulose and mix them. Heat them to 70°C in a water bath under nitrogen protection and reflux conditions. Add the mixed monomer solution and modified nano-alumina suspension dropwise thereto at the same time and react for 1h to 2h. Then heat them to 120°C to 130°C, reflux the n-heptane through the azeotropic reaction of n-heptane and water while extracting water from the reaction system. Then cool them to 70°C to 80°C, add N,N'-methylenebispropionamide aqueous solution, and continue to keep warm for 1h to 3h.

[0137] In a third aspect of the present application, a refrigeration-type cold storage agent is provided, which contains the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application.

[0138] In one embodiment, the refrigeration type coolant is suitable for freezing requirements of -15°C to -5°C.

[0139] The fourth aspect of the present application provides a cold storage agent for storing photolithographic materials, which contains the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application.

[0140] Photolithography materials are key upstream materials in the printed circuit board, liquid crystal display, and semiconductor industry chains. Their components often contain a large number of reactive groups, which are prone to crosslinking or shedding, thus affecting the performance of the materials. Therefore, the storage and transportation conditions and use cycles of photolithography materials must be strictly controlled. For photolithography materials containing highly chemically active groups, the storage and transportation temperature must be controlled within the range of -15°C to 0°C or even lower. Examples of photolithography materials include photoresist (PR), anti-reflective coating (ARC), spin-on carbon (SOC) hard masks, and spin-on glass (SOG) hard masks used in the photolithography process.

[0141] The cold storage agent for storage of photolithographic materials of the present application contains the flexible phase-change cold storage material described in any of the above technical solutions, or the flexible phase-change cold storage material prepared by the preparation method described in any of the above technical solutions. The cold storage agent for storage of photolithographic materials has a stable phase change temperature of -15°C to -5°C, which can prevent the photolithographic materials from deteriorating during storage and transportation.

[0142] In a fifth aspect, the present application provides a flexible cold storage pack comprising a sealed package and a cold storage agent filled within the sealed package. The cold storage agent comprises the flexible phase-change cold storage material provided in the first aspect of the present application, or the flexible phase-change cold storage material prepared by the preparation method provided in the second aspect of the present application. The cold storage agent exhibits high cold storage density, high cyclic stability, and exhibits shape-shifting properties at room temperature. It can be flexibly placed in the space surrounding the packaging of active materials, such as photolithographic materials, as needed.

[0143] In one embodiment, the sealing packaging material can be selected from polyethylene, polyester, polycarbonate or polypropylene. These materials have certain flexibility and elasticity, which can enable the flexible phase change cold storage material to be in close contact with the sealed package, thereby facilitating heat exchange between the cold storage package and the object to be stored and transported.

[0144] The following are some specific examples.

[0145] The raw materials and reagents involved in the following specific examples can be obtained commercially, or can be prepared by those skilled in the art according to known methods.

[0146] For experimental parameters not specified in the following specific examples, reference is made to the guidance given in this application document, and reference may also be made to experimental manuals in the art or other experimental methods known in the art, or to the experimental conditions recommended by the manufacturer.

[0147] 1. Provide raw materials for flexible phase change cold storage materials

[0148] 1.1. Preparation of modified nucleating agent

[0149] Weigh 0.5g of nano-alumina, add 30mL of ethyl acetate, mechanically stir to mix, then place in an ultrasonic cleaner at room temperature for 30 minutes for ultrasonic dispersion to obtain a nano-alumina suspension. Add 10g of a 0.5% by mass aqueous solution of silane coupling agent KH570 to the nano-alumina suspension and continue ultrasonication for 5 minutes. Transfer the reaction solution to a flask equipped with a reflux condenser, react at 80°C for 5 hours, then cool to room temperature and filter to obtain a precipitate. Wash the precipitate with ethyl acetate to form a dispersion, transfer the dispersion to a centrifuge tube, centrifuge at 12,000 rpm at room temperature, wash the resulting precipitate with deionized water, and then centrifuge. Place the resulting product in a vacuum drying oven at 40°C for 24 hours to obtain the modified nano-alumina.

[0150] Thermogravimetric analysis was used to determine the weight percentage of the grafted groups in the modified nano-alumina at a heating rate of 10°C / min and a test temperature of 25-800°C. The result showed that the groups accounted for 1.562% of the weight of the modified nano-alumina.

[0151] 1.2. Preparation of hydrophilic polymers

[0152] 1.2.1. Preparation of hydrophilic polymer HP-01

[0153] 94 g (1.044 mol) of an 80% aqueous acrylic acid solution was placed in a 500 mL flask. While mechanically stirring and cooling the flask with ice, 127 g (0.794 mol) of a 25% aqueous sodium hydroxide solution was added dropwise to the flask, yielding a mixed solution with a molar ratio of acrylic acid to sodium acrylate of 1:3.17. Subsequently, 0.9 g (0.0025 mol) of a 20% aqueous acrylamide solution and 0.15 g of potassium persulfate were added to the flask to prepare a monomer aqueous solution. 0.1 g of modified nano-alumina was then dispersed at high speed in 50 g of n-heptane to form a suspension.

[0154] In a 1 L flask, add 448 g of n-heptane and 3.0 g of ethyl cellulose, stir and mix, and heat to 70° C. in a water bath under nitrogen protection and reflux.

[0155] The monomer solution was slowly added dropwise to the flask for 1 hour. During this process, the suspension of modified nano-alumina was also added dropwise to the flask for 10 minutes.

[0156] After all reactants were added dropwise, the reaction was continued for 1.5 hours. The reaction flask was placed in a 125°C oil bath. While the n-heptane was refluxed by azeotropic reaction of n-heptane and water, water was extracted from the reaction system. The reaction temperature was then lowered to 75°C and 5.775 g (0.75 × 10 -3 mol) weight content of 2% N, N'-methylenebispropionamide aqueous solution, continue to keep warm for 2h, and cool.

[0157] The obtained product was placed in a vacuum oven at 80° C. and dried, and the large particles were crushed. The obtained product was a hydrophilic polymer, which was recorded as HP-01.

[0158] 1.2.2. Preparation of hydrophilic polymer HP-02

[0159] The preparation steps refer to the preparation method of HP-01, except that modified nano-alumina is not synthesized. During the synthesis of the hydrophilic polymer, 0.1g of nano-alumina is added to the reaction system instead of 0.1g of modified nano-alumina. The obtained hydrophilic polymer is recorded as HP-02.

[0160] 1.2.3. Preparation of hydrophilic polymer HP-03

[0161] The preparation steps were similar to those for HP-01, except that nano-alumina and modified nano-alumina were not added during the synthesis of the hydrophilic polymer. The resulting hydrophilic polymer was designated HP-03. Gel permeation chromatography (GPC) analysis revealed a weight-average molecular weight of 15,000 for HP-03. (HP-01 and HP-02 contain inorganic nanoparticles in their polymer structures, making GPC analysis of molecular weight impossible.)

[0162] 1.2.4. Preparation of hydrophilic polymer HP-04

[0163] The preparation steps refer to the preparation method of HP-01, except that 0.05 g of modified nano-alumina is added to the reaction system instead of 0.1 g of nano-modified alumina during the synthesis of the hydrophilic polymer. The obtained hydrophilic polymer is recorded as HP-04.

[0164] 2. Preparation of flexible phase change cold storage materials

[0165] 2.1. Prepare the raw materials

[0166] Prepare the raw materials by weighing the components according to the ratios in Tables 1 and 2. The total weight of the raw materials is 1 kg, of which:

[0167] The inorganic salt is selected from potassium chloride and barium chloride.

[0168] The hydrophilic polymer is selected from hydrophilic resins HP-01, HP-02, HP-03 and HP-04. The hydrophilic resin HP-01 contains a modified nucleating agent, the hydrophilic resin HP-02 contains a nucleating agent, the hydrophilic resin HP-03 does not contain a modified nucleating agent and a nucleating agent, and HP-04 contains a small amount of a modified nucleating agent; the nucleating agent is nano-alumina; and the modified nucleating agent is nano-alumina grafted with a silane coupling agent KH570.

[0169] The cross-linking enhancer is selected from nano-silicon dioxide with an average particle size of 30 nm (CS-01), nano-silicon dioxide with an average particle size of 80 nm (CS-02), and carboxymethyl cellulose (CS-03).

[0170] The corrosion inhibitor is sodium benzoate.

[0171] The preparation process of phase change gel is carried out at room temperature.

[0172] The speed of mechanical stirring is controlled at 30r / min~100r / min.

[0173] The mechanical stirring time for forming the first solution was 1.5 h, the mechanical stirring time for forming the first gel was 1 h, and the mechanical stirring time for forming the second gel was 1.5 h.

[0174] Table 1. Raw material ratios for the preparation of flexible phase-change cold storage materials.

[0175] Table 2. Raw material ratios for the comparative example of preparing flexible phase change cold storage materials.

[0176] 2.2. Preparation of flexible phase change cold storage materials

[0177] The preparation process of the flexible phase change cold storage material is carried out at room temperature and specifically includes the following steps:

[0178] (1) dissolving an inorganic salt in deionized water, stirring at 80 r / min for 1.5 h to obtain an inorganic salt aqueous solution, adding a corrosion inhibitor, mixing, and stirring at 80 r / min for 1.5 h to obtain a first solution;

[0179] (2) mixing the first solution and the hydrophilic polymer, stirring at 40 rpm for 1 h to prepare a first gel;

[0180] (3) The first gel and the cross-linking enhancer were mixed and stirred at 40 r / min for 1.5 h.

[0181] 3. Performance Testing

[0182] The phase change thermal performance and cycle stability of the flexible phase change cold storage materials prepared in the examples and comparative examples were tested and evaluated by the following methods. The specific methods are:

[0183] 3.1. Phase change thermal performance test of flexible phase change cold storage material.

[0184] The phase change thermal properties of flexible phase change cold storage materials mainly include the phase change temperature, phase change latent heat and supercooling of the flexible phase change cold storage materials.

[0185] The latent heat of phase change of flexible phase change cold storage material is determined by differential calorimetry. The steps are as follows: take the flexible phase change cold storage material prepared in the embodiment and comparative example as samples, the mass of the sample can be 3mg to 8mg, place each sample in a sealed aluminum crucible, and then use a differential calorimeter scanner (model T25, produced by TA) to test the samples separately. The temperature range of the test is -50℃ to 40℃, the heating rate of the test is 10℃ / min, nitrogen is used as the protective gas, and the flow rate of nitrogen is 50mL / min. This test can obtain the heat flux density vs. temperature curve and heat flux density vs. time curve of the sample. The area where the phase change endothermic peak in the heat flux density vs. time curve is located is integrated, and the peak area of ​​the phase change endothermic peak obtained is the phase change latent heat of the sample.

[0186] Considering that the phase transition peaks shown in the heat flux density vs. temperature curves obtained during differential scanning calorimetry testing of the flexible phase-change cold storage materials prepared in the Examples and Comparative Examples of this application are relatively wide, and the heating rate during the testing is too rapid, using the starting temperature of this phase transition peak as the phase transition temperature of the flexible phase-change cold storage materials using traditional testing methods is inaccurate. Therefore, the phase transition temperatures of the flexible phase-change cold storage materials in the Examples and Comparative Examples of this application were measured using the step-heating curves of the flexible phase-change cold storage materials. The supercooling of the flexible phase-change cold storage materials was measured using the step-cooling curves of the flexible phase-change cold storage materials.

[0187] The testing steps for the step heating and step cooling curves of the flexible phase-change cold storage material are as follows: at room temperature, place 40g of the flexible phase-change cold storage material prepared in the embodiments and comparative examples in a 100mL polyethylene test tube, seal it, and place it on a test tube rack. A T-type thermocouple probe with a diameter of 0.5mm is inserted into the test tube to measure the temperature of the gel in the flexible phase-change cold storage material within the test tube. The test tube rack containing the test sample is placed in a refrigerator with a refrigeration temperature of -30°C. In the test tube containing the flexible phase-change cold storage material, the other end of the T-type thermocouple probe for temperature measurement is connected to a thermocouple wire, which is passed through the refrigerator door and connected to a data acquisition instrument to record the temperature values ​​collected by the probe. The data recording interval is 10s. This method can be used to obtain the temperature-time curve of the flexible phase-change cold storage material during the process of cooling from room temperature to refrigerator refrigeration temperature (i.e., the step cooling curve of the flexible phase-change cold storage material). The test tube containing the flexible phase change cold storage material and connected to a thermocouple is taken out of the refrigerator and placed at room temperature, so that the flexible phase change cold storage material is naturally heated. The temperature-time curve of the flexible phase change cold storage material recorded in this process is the step thermal curve of the flexible phase change cold storage material. The step thermal curve of the obtained flexible phase change cold storage material sample is processed, and the temperature corresponding to the intersection of the tangent of the curve of the rapid temperature rise before reaching the phase change constant temperature (or near constant temperature) section and the tangent of the phase change constant temperature (or near constant temperature) section curve in the step thermal curve is recorded as T1, which is the phase change temperature of the flexible phase change cold storage material. The step cooling curve of the flexible phase change cold storage material sample is processed. The starting point temperature of the phase change platform in the step cooling curve is recorded as T2. The supercooling degree of the flexible phase change cold storage material sample can be calculated using Formula 1:

[0188] Formula 1:

[0189] Subcooling = T1-T2;

[0190] 3.2. Cyclic stability testing and evaluation of flexible phase change thermal storage materials

[0191] The cyclic stability performance of the flexible phase change cold storage material is mainly evaluated by testing whether the flexible phase change cold storage material has a change in the latent heat value of the phase change, whether cold storage failure occurs, and whether liquid water seepage occurs after multiple cooling / heating cycle tests.

[0192] The hot and cold cycle test method of the flexible phase change cold storage material sample is as follows: first, at room temperature, the flexible phase change cold storage material prepared in the embodiment and the comparative example is placed in a 100mL polyethylene test tube and a thermocouple probe is placed, and then sealed. The test tube is transferred to a refrigerator with a refrigeration temperature of -30°C and frozen for 7 hours until the flexible phase change cold storage material completely turns into a white solid. Then the test tube is taken out and thawed at room temperature for 6 hours until the flexible phase change cold storage material completely turns into a translucent gel. Repeat the freezing / thawing operation of the test tube to make the flexible phase change cold storage material undergo repeated cooling / heating cycles, and the number of repetitions is 100 times.

[0193] The flexible phase change cold storage material sample that has undergone 100 cycles was taken, and the phase change latent heat value of the sample was measured by differential scanning calorimetry, which was recorded as ΔH2. The phase change latent heat value of the flexible phase change cold storage material sample that had not undergone the phase change cycle test was measured, which was recorded as ΔH1. The change rate of the phase change latent heat value of the flexible phase change cold storage material before and after the cycle test can be calculated by formula 2:

[0194] Formula 2:

[0195] Phase change latent heat change rate = (△H2-△H1) / △H1×100%;

[0196] Evaluation of the latent heat change of flexible phase change cold storage materials during cyclic testing:

[0197] ○: The latent heat change rate of phase change is less than 3%;

[0198] △: The latent heat change rate of phase change is greater than 3% and less than 8%;

[0199] ×: The latent heat change rate of phase change is 8% or more.

[0200] The temperature-time curves of the cooling process of the flexible phase-change cool storage material in each test cycle are compared. If a constant temperature platform appears in the temperature-time curve of the cooling process of the flexible phase-change cool storage material in any cycle, it is determined that the flexible phase-change cool storage material successfully stores cool in this cycle; if no constant temperature platform appears in the temperature-time curve of the cooling process of the flexible phase-change cool storage material in any cycle, it is determined that the flexible phase-change cool storage material fails to store cool in this cycle.

[0201] Whether there is leakage of free water in the flexible phase change cold storage material after 100 cycle tests can be determined by visual observation.

[0202] The test results of the flexible phase-change cold storage materials prepared in the above examples and comparative examples are shown in Table 3.

[0203] Table 3. Performance test results of flexible phase change cold storage materials.

[0204] As shown in Table 3, the phase change latent heat value of the phase change cool storage gel obtained in each embodiment (Example 1 to Example 5) is greater than 230 kJ / kg, the phase change temperature is controlled in the range of -15°C to -5°C, and the supercooling is less than 1.1°C. After 100 cooling / thawing cycle tests, the phase change latent heat change rate of the phase change cool storage gel is less than 3%, and there is no problem of cool storage failure or free water seepage, showing high phase change latent heat and high cycle stability.

[0205] Compared with any of Examples 1 to 5, the phase change cold storage gel prepared in the comparative example, in the absence of a crosslinking enhancer (Comparative Example 1), using CS-02 as a crosslinking enhancer (Comparative Example 2), or only with the crosslinking enhancer CS-01 without adding a hydrophilic polymer (Comparative Example 3), all experienced free water leakage after thermal cycling.

[0206] When the commonly used thickener CS-03 was used as a crosslinking enhancer (Comparative Example 4), a large amount of free water precipitated from the phase-change gel, resulting in severe phase separation. Phase change performance and cyclic stability testing could not be performed. This may be because, while the CS-03 structure contains numerous hydroxyl groups that can form a hydrogen-bonding network with water molecules, the network lacks solid particles to ensure structural rigidity, resulting in significant water precipitate due to its drastic shrinkage. Furthermore, the phase-change cool storage gel using only a hydrophilic polymer as a flexible, shape-setting medium (Comparative Example 1) exhibited a low latent heat of phase change, while the phase-change gel (Comparative Example 3) with the addition of the same dose of the crosslinking enhancer CS-01 achieved a higher latent heat of phase change. The phase-change cool storage gels of Comparative Examples 5, 6, and 8 exhibited relatively high supercooling. This is due to the partial aggregation of the nucleating agent within the phase-change gel of Comparative Example 5, the absence of a nucleating agent in the hydrophilic polymer used in Comparative Example 6, and the relatively low amount of modified nucleating agent copolymerized in the hydrophilic polymer of Comparative Example 8, resulting in a phase-change cool storage gel containing relatively low nucleating agent. The phase-change cool storage gel prepared in Comparative Example 7, which contained a relatively large amount of hydrophilic polymer, exhibited a relatively low latent heat of phase change.

[0207] Figure 1 compares the flexible shaping performance of the phase-change cool storage gels prepared in Examples and Comparative Examples of the present application. Figure 1A and Figure 1B represent the flexible shaping performance of the phase-change cool storage gels prepared in Example 1 and Comparative Example 1, respectively. As shown in Figure 1, the cool storage gel without the crosslinking enhancer CS-01 exhibits a loose state (Figure 1B), with the granular gel adhering to the container wall. However, with the addition of the crosslinking enhancer CS-01, the gel exhibits a reduced looseness (Figure 1A), significantly improving its flexible shaping performance.

[0208] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited in their entirety and for all purposes. When cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When cited documents are involved in this application, the examples and preferred embodiments of the cited relevant technical features may also be incorporated into this application as references, but are limited to the ability to implement this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be adaptively amended according to the description in this application.

[0209] The various technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. In order to make the description concise, not all possible combinations of the various technical features in the above-mentioned implementation modes and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the description in this specification.

[0210] The embodiments described above only express several implementation methods of the present application, but they should not be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the scope of protection of the present application. It should also be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims, and the description and drawings may be used to explain the contents of the claims.

Claims

1. A flexible phase change cold storage material, characterized in that: The content by weight percentage includes: The inorganic salt aqueous solution comprises an inorganic salt and water, wherein the weight of the inorganic salt accounts for 3% to 40% of the total weight of the inorganic salt aqueous solution; The hydrophilic polymer is copolymerized by a mixed monomer, a modified nucleating agent and a crosslinking agent; the mixed monomer includes an acrylic acid compound, an acrylate compound and an acrylamide monomer in a molar ratio of 1:(3-8):(0.05-0.5); the modified nucleating agent is a product obtained by surface modification of the functional group of the nucleating agent with a silane coupling agent, wherein the modified group accounts for 0.5% to 5% of the total weight of the modified nucleating agent; The cross-linking enhancer is nano silicon dioxide with a particle size of 10nm to 80nm; The other additives include corrosion inhibitors.

2. The flexible phase change cold storage material according to claim 1, characterized in that: The modified nucleating agent is connected to the main chain or side chain of the hydrophilic polymer in the form of a chemical bond.

3. The flexible phase change cold storage material according to claim 1, characterized in that: The weight of the modified nucleating agent is 0.05% to 0.5% of the total weight of the mixed monomers; The molar amount of the crosslinking agent added relative to the acrylic compound is 0.05% to 0.5%.

4. The flexible phase-change cold storage material according to any one of claims 1 to 3, characterized in that: It has at least one of the following technical features: (1) the acrylic compound is at least one selected from acrylic acid and methacrylic acid; (2) the acrylate compound is at least one selected from the group consisting of sodium acrylate, potassium acrylate, sodium methacrylate and potassium methacrylate; (3) the acrylamide compound is at least one selected from acrylamide and methacrylamide; (4) the cross-linking agent is at least one selected from ethylene glycol diglycidyl ether, N,N'-methylenebispropionamide, N-vinyl-2-pyrrolidone and ethylene glycol diacrylate; (5) The nucleating agent is at least one selected from nano zinc oxide, nano aluminum oxide, nano silicon carbide and carbon nanotubes; (6) The corrosion inhibitor is selected from at least one of nitrite, chromate, phosphate, silicate and benzoate.

5. A method for preparing a flexible phase-change cold storage material, characterized in that: The steps include: Prepare the raw materials according to the formula of the flexible phase change cold storage material according to any one of claims 1 to 4; Taking the inorganic salt aqueous solution, optionally adding the other additives and mixing, to prepare a first solution; Under a first dispersion condition, adding the hydrophilic polymer to the first solution and mixing to obtain a first gel; Under the second dispersing condition, the cross-linking enhancer is added to the first gel.

6. The method for preparing the flexible phase-change cold storage material according to claim 5, characterized in that: The hydrophilic polymer is prepared by emulsion polymerization; The modified nucleating agent is added during the emulsion polymerization process to carry out copolymerization.

7. The preparation method according to claim 5, characterized in that: The modified nucleating agent is prepared by the steps comprising the following preparation method: The nucleating agent is dispersed in an organic solvent, a silane coupling agent is added and mixed, ultrasonicated, and heated to 80° C. to 90° C. for reaction.

8. The preparation method according to any one of claims 5 to 7, characterized in that: At least one of the following preparation conditions is met: (1) The first dispersion condition includes: stirring at 30 r / min to 100 r / min for 0.5 h to 2 h; (2) The second dispersion condition includes: stirring at 30 r / min to 100 r / min for 0.5 h to 3.5 h.

9. A refrigeration type coolant, characterized in that: The invention comprises the flexible phase-change cold storage material according to any one of claims 1 to 4, or the flexible phase-change cold storage material prepared by the preparation method according to any one of claims 5 to 8.

10. A coolant for storing photolithographic materials, characterized in that: The invention comprises the flexible phase-change cold storage material according to any one of claims 1 to 4, or the flexible phase-change cold storage material prepared by the preparation method according to any one of claims 5 to 8.

11. The coolant for storing photolithographic materials according to claim 10, characterized in that: The photolithography materials include photoresist, anti-reflection coating, spin-on carbon hard mask and spin-on glass hard mask.

12. A flexible cold storage pack, characterized in that: It includes a sealed package and a coolant filled in the sealed package; The cold storage agent contains the flexible phase-change cold storage material according to any one of claims 1 to 4, or the flexible phase-change cold storage material produced by the production method according to any one of claims 5 to 8.

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