Solvent-resistant phase change microcapsule coated with organic-inorganic hybrid wall material and preparation method of solvent-resistant phase change microcapsule

Abstract

The invention provides a solvent-resistant phase change microcapsule coated with an organic-inorganic hybrid wall and a preparation method of the solvent-resistant phase change microcapsule. The method comprises the following steps: adding an interface grafting agent and a phase change material into a polar solvent for grafting reaction to prepare a core material dispersion liquid; adding an organic matter reaction monomer containing inorganic matter components, a pure organic matter reaction monomer, an initiator and a cross-linking agent into the core material dispersion liquid for in-situ polymerization reaction to prepare a reaction system containing phase change microcapsules; washing, separating and drying to obtain the solvent-resistant phase change microcapsule. According to the method, inorganic components are introduced into a phase change microcapsule wall material by adopting a grafting method and an in-situ polymerization method, so that the solvent resistance of the phase change microcapsule is improved, the particle size of the phase change microcapsule is continuously controllable in micron and nano scales, the distribution range is narrow, the coating rate is high, the preparation process is simple, the energy consumption is low, and industrial production is easy; the method can be widely applied to the fields of cooling liquid, electronic product thermal control, phase change temperature control assemblies and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of phase change energy storage materials, and particularly relates to a solvent-resistant phase change microcapsule coated with an organic-inorganic hybrid wall material and a preparation method thereof. BACKGROUND

[0002] In the process of traditional fuel to green energy conversion, most of the energy is wasted in the form of heat energy, leading to a mismatch between energy supply and demand. In order to achieve green and sustainable economic development, more and more researchers pay attention to the research of renewable and sustainable energy. At present, the research in this field mainly combines energy utilization with heat energy storage to achieve efficient energy utilization.

[0003] Among them, heat energy storage mainly collects and saves excess energy, and then effectively utilizes it at the most needed time and place, which can be achieved through various technologies.

[0004] Among them, phase change energy storage is an effective technical means in heat energy storage, which relies on phase change materials. Phase change materials are a kind of materials that can respond to the absorption or release of energy from the outside in the form of latent heat through phase change, and have good energy storage (including cold storage and heat storage) performance. In recent years, it has been widely used in building energy saving, industrial waste heat recovery and other fields.

[0005] Phase change materials can be divided into four types according to phase change form: liquid-solid phase change, solid-solid phase change, liquid-gas phase change and solid-gas phase change. Among them, solid-gas phase change materials and liquid-gas phase change materials will produce a large amount of gas in the phase change process, which is not easy to control, and solid-solid phase change materials are few in variety and high in price. Therefore, solid-liquid phase change materials become the most commonly used and researched phase change materials.

[0006] However, solid-liquid phase change materials are prone to flow, penetration leakage and other problems during phase change. In order to prevent such phenomena, phase change microcapsule technology becomes a feasible choice to solve the problems.

[0007] There are three major methods for preparing phase change microcapsules: physical method, chemical method and physical-chemical method. Among them, the physical method includes solvent evaporation method, spray drying method, point flow body dynamic spraying method, etc.; the chemical method includes emulsion polymerization method, miniemulsion polymerization method, interfacial polymerization method and in-situ polymerization method, etc.; the physical-chemical method includes coagulation method and sol-gel method, etc.

[0008] Among these methods, in-situ polymerization method is more widely used due to its low preparation cost, good chemical properties, high stability and other advantages.

[0009] The constituent materials of phase change microcapsules include wall material and core material. Among them, the wall material can be generally divided into organic wall material and inorganic wall material.

[0010] Organic-based phase change microcapsules are obtained by encapsulating phase change materials with organic polymers, typically exhibiting high encapsulation rates (or enthalpy retention) and good encapsulation effects. However, organic-based wall materials are generally flammable, have low thermal conductivity, poor resistance to swelling, and often contain unreacted monomers, limiting the large-scale application of organic-based phase change microcapsules.

[0011] Inorganic phase change microcapsules are obtained by encapsulating phase change materials on their surface using the hydrolysis-condensation reaction of inorganic precursors. They exhibit excellent stability and high thermal conductivity. However, due to the poor toughness of inorganic materials, the inorganic capsule walls of inorganic phase change microcapsules are prone to fracture during use, thus easily damaging the microcapsule structure.

[0012] To address the issues of flammability, poor solvent resistance, and monomer residue in organic wall materials, as well as the insufficient toughness of inorganic wall materials, some researchers have proposed preparing phase change microcapsules with inorganic-organic hybrid wall materials.

[0013] For example, CN111205830 provides an organic-inorganic hybrid shell bifunctional phase change capsule and its preparation method; CN113058512A provides an organic-inorganic composite wall material-coated phase change microcapsule and its preparation method and application; CN113563850A provides a multi-element hybrid inorganic single-shell multi-temperature zone phase change microcapsule and its preparation method; CN118126684A provides a thermally enhanced organic-inorganic hybrid shell phase change microcapsule and its preparation method. However, these phase change microcapsules are all prepared by emulsion polymerization and interfacial polymerization methods, which all require the preparation of aqueous and oil phases and complex and harsh process conditions such as high shear or ultrasound. These phase change microcapsules generally suffer from poor oil solvent resistance.

[0014] The inventors have proposed a method for preparing solvent-resistant phase change microcapsules using an organic-inorganic hybrid shell as the wall material through in-situ polymerization. The capsule wall of these phase change microcapsules not only combines the advantages of both organic and inorganic materials, but more importantly, it also improves the enthalpy and solvent resistance of the microcapsules. Furthermore, the reaction process is simple, reduces production costs, and is easy to industrialize. Summary of the Invention

[0015] To address the aforementioned technical problems of existing phase change microcapsules, the present invention provides, in a first aspect, a method for preparing phase change microcapsules coated with an organic-inorganic hybrid wall material, the method comprising the following steps:

[0016] (1) Add an interfacial grafting agent and a phase change material to a polar solvent and carry out a grafting reaction while stirring to obtain a core material dispersion;

[0017] (2) The first organic reactive monomer, the second organic reactive monomer, the initiator and the crosslinking agent are added to the core material dispersion to carry out in-situ polymerization reaction to obtain a reaction system containing phase change microcapsules, wherein the first organic reactive monomer is an organic reactive monomer containing inorganic components and the second organic reactive monomer is a pure organic reactive monomer.

[0018] (3) The reaction system is washed, separated and dried to obtain a solid product as the solvent-resistant phase change microcapsules.

[0019] In some preferred embodiments, the first organic reactive monomer is a silane coupling agent monomer, preferably, the silane coupling agent monomer is at least one selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane and 3-(trimethoxysilyl)propyl methacrylate.

[0020] In some other preferred embodiments, the second organic reactive monomer is at least one selected from styrene, methyl styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, tert-butyl acrylate, and isooctyl acrylate.

[0021] In some other preferred embodiments, the interface grafting agent is selected from at least one of maleic anhydride, acrylic acid, and methacrylic acid.

[0022] In other preferred embodiments, the crosslinking agent is selected from crosslinking agents containing unsaturated bonds, preferably from styrene derivatives and esters containing double bonds. More preferably, the styrene derivative is selected from at least one of divinylbenzene, styrene-ethyltrimethylsiloxane, and 1,3-diisopropenylbenzene. Further preferably, the ester containing double bonds is selected from at least one of ethylene glycol dimethacrylate, propylene glycol dimethacrylate, butylene glycol dimethacrylate, and ethylene glycol dimethacrylate.

[0023] In some other preferred embodiments, the polar solvent is selected from toluene, methanol, n-octane, n-butane, petroleum ether, cyclohexane, and n-pentane, preferably toluene or n-octane.

[0024] In some other preferred embodiments, the initiator is an oil-soluble initiator.

[0025] Preferably, the oil-soluble initiator is an azo initiator or a peroxide initiator.

[0026] More preferably, the azo initiator is selected from at least one of azobisisobutyronitrile, azobisisobutyronitrile, dimethyl azobisisobutyrate, and azoisobutylcyanoformamide.

[0027] Preferably, the peroxide initiator is selected from at least one of benzoyl peroxide, dodecyl peroxide, dicumyl peroxide, diisopropyl peroxide, diisopropyl percarbonate, benzoyl tert-butyl peroxide, and methyl ethyl ketone peroxide. More preferably, the azo initiator is azobisisobutyronitrile; and even more preferably, the peroxide initiator is benzoyl peroxide.

[0028] In some other preferred embodiments, the phase change material is a solid-liquid phase change material. The solid-liquid phase change material can be an alkane alcohol-based solid-liquid phase change material, a sugar alcohol-based solid-liquid phase change material, a polyether-based solid-liquid phase change material, and / or a mixed solid-liquid phase change material.

[0029] Preferably, the n-alkane alcohol-based solid-liquid phase change material is 1-tetradecyl alcohol and / or 1-octadecyl alcohol; the sugar alcohol-based solid-liquid phase change material is mannitol, xylitol, erythritol, and / or sorbitol; the polyether-based solid-liquid phase change material is polyethylene glycol and / or polybutanediol; and the mixed solid-liquid phase change material is a mixture comprising organic and inorganic phase change materials. More preferably, the sugar alcohol-based solid-liquid phase change material is mannitol, xylitol, erythritol, and / or sorbitol.

[0030] In some preferred embodiments, the interface grafting agent accounts for 0.1-30% (e.g., 1, 2, 5, 10, 20, 25 or 30%) of the mass of the polar solvent, preferably 0.1-10%.

[0031] In other preferred embodiments, the phase change material accounts for 1-50% (e.g., 1, 2, 5, 10, 20, 30, 40 or 50%) of the mass of the polar solvent, preferably 1-30%.

[0032] In some other preferred embodiments, the mass ratio of the first organic reactive monomer to the second organic reactive monomer is 1:0.1-100 (e.g., 1:0.1, 1:0.2, 1:0.5, 1:1, 1:4, 1:10, 1:20, 1:50 or 1:100), preferably 1:0.1-50.

[0033] In some other preferred embodiments, the total mass ratio of the first organic reactive monomer and the second organic reactive monomer to the mass ratio of the phase change material can be 1:0.01-100 (e.g., 1:(0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50 or 100)), preferably 1:0.01-50.

[0034] In other preferred embodiments, the crosslinking agent accounts for 0.1-20% (e.g., 0.1, 0.2, 0.5, 1, 2, 5, 10, 15 or 20%) of the mass of the polar solvent, preferably 0.1-10%.

[0035] In other preferred embodiments, the initiator comprises 0.001-10% (e.g., 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5 or 10%) of the mass of the polar solvent, preferably 0.001-1%.

[0036] In other preferred embodiments, the total mass of the first organic reactive monomer and the second organic reactive monomer accounts for 0.001-10% (e.g., 0.001, 0.002, 0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5 or 10%) of the mass of the polar solvent, preferably 0.001-1%.

[0037] In some other preferred embodiments, the stirring speed in step (1) is 100-1000 rpm (e.g., 100, 200, 500 or 1000 rpm), and the stirring time for uniform mixing is 100-500 min (e.g., 100, 200, 300, 400 or 500 min).

[0038] In some other preferred embodiments, the reaction is carried out by stirring and heating after the addition of materials in step (2). Preferably, the stirring speed used for the heating reaction is 100-1000 rpm (e.g., 100, 200, 500 or 1000 rpm), and the stirring time used for the heating reaction is 10-70 h (e.g., 10, 20, 30, 40, 50, 60 or 70 h).

[0039] In some other preferred embodiments, steps (1) and (2) are performed independently in an inert atmosphere, preferably nitrogen.

[0040] In some other preferred embodiments, the temperature of the emulsification reaction in step (1) and the temperature of the in-situ polymerization reaction in step (2) are independently 30-100°C (e.g., 30, 40, 50, 60, 70, 80, 90 or 100°C), preferably 50-90°C.

[0041] In some other preferred embodiments, the separation method in step (3) is centrifugal separation and / or vacuum filtration separation, and the drying method is atmospheric pressure drying and / or vacuum drying.

[0042] In some other preferred embodiments, the washing solution used in step (3) accounts for 10%-95% of the total mass of the items being washed (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90 or 95%).

[0043] Preferably, the centrifugation speed in step (3) is 500-2000 r / min (e.g., 500, 800, 1000, 1200, 1400, 1600, 1800 or 2000 rpm), preferably 800-1800 rpm, and the filter paper used for vacuum filtration has a pore size of 30μm-500μm (e.g., 30, 50, 100, 200, 300, 400 or 500μm).

[0044] In some other preferred embodiments, the temperature of the vacuum drying chamber used for vacuum drying is 35-100℃, preferably 45-80℃; the vacuum degree is -0.05MPa to -0.08MPa.

[0045] The present invention provides, in a second aspect, phase change microcapsules prepared by the preparation method described in the first aspect of the present invention.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] (1) Good solvent resistance.

[0048] (2) The reaction conditions are mild, and there is no need for ultrasonic treatment or high-speed (e.g., above 1000 rpm) stirring. In-situ polymerization can even be achieved at as low as 100 rpm.

[0049] (3) The particle size of microcapsules is easy to control. Phase change microcapsules with a continuously adjustable particle size distribution between 10-150 μm can be prepared by selecting phase change materials with appropriate particle sizes;

[0050] (3) The reaction steps are simple. The preparation can be completed by grafting reaction and in-situ polymerization reaction after only one feeding.

[0051] (4) Lower cost. Due to the mild reaction conditions and simple reaction steps, the cost can be significantly reduced.

[0052] (5) Good cycle stability. The shell of the phase change microcapsule has good toughness and is not easily damaged. Attached Figure Description

[0053] Figure 1 This is a scanning electron microscope (SEM) image of the solvent-resistant phase change microcapsules coated with an organic-inorganic hybrid wall material prepared in Example 1 of the present invention.

[0054] Figure 2 Differential scanning calorimetry (DSC) curve of solvent-resistant phase change microcapsules coated with organic-inorganic hybrid wall material prepared in Example 1 of the present invention;

[0055] Figure 3 This is a microscopic image of the solvent-resistant phase change microcapsules coated with the organic-inorganic hybrid wall material described in Example 1 of the present invention after 10 cycles of hot and cold cycling in white oil. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Example

[0058] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0059] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0060] Example 1

[0061] This embodiment prepares a phase change microcapsule of organic-inorganic hybrid wall material. The preparation process includes the following steps:

[0062] (1) Raise the temperature of the 50L reactor to 70℃, weigh 12L of polar solvent toluene, 200g of interfacial grafting agent maleic anhydride and 2000g of phase change material mannitol, add them from the feed port of the reactor, and then heat in a nitrogen atmosphere and maintain the temperature range of 65 to 75℃ and stir continuously (stirrer speed is 200rpm) for 5h to obtain the core material dispersion.

[0063] (2) Weigh 48g of the second organic monomer styrene (a free radical monomer), 32g of the first organic monomer (a free radical monomer) γ-methacryloyloxypropyltrimethoxysilane (kh570), 80g of the crosslinking agent divinylbenzene, and 56g of the initiator azobisisobutyronitrile and add them to the reaction vessel. Heat to 70°C, stir at 200 rpm, and heat and stir for 24 hours.

[0064] (3) The reactants were removed into a container and allowed to stand for stratification. The upper layer of polar solvent, toluene, was removed into a waste container. 8 L of toluene was added to the container for washing and filtration. Then, 3 L of toluene was used for washing again and filtration. The filter paper used for filtration had a pore size of 60 μm. The filtration product was poured out and placed in a fume hood for ventilation and drying to obtain phase change microcapsules coated with an organic-inorganic hybrid wall material. A scanning electron microscope image of the phase change microcapsules coated with the organic-inorganic hybrid wall material prepared in this embodiment is shown below. Figure 1 As shown. From Figure 1 As can be seen from the above, the phase change microcapsules coated with the organic-inorganic hybrid wall material prepared in this embodiment have a size of 35-55 μm, the phase change material has a rough surface, and the coating effect is good.

[0065] Figure 2 This is a DSC image of the phase change microcapsules coated with an organic-inorganic hybrid wall material prepared in Example 1 of the present invention. From... Figure 2 As can be seen from the data, the latent heat of phase change of the phase change microcapsules coated with the organic-inorganic hybrid wall material prepared in this embodiment is 249.42 J / g.

[0066] Figure 3 The image shows a microscopic image of the phase change microcapsules coated with the organic-inorganic hybrid wall material described in Example 1 of this invention after 10 cycles of hot and cold cycling in white oil. One cycle consisted of heating from room temperature to 200°C at a rate of 4.5°C / min and then cooling back to room temperature at a rate of 4.5°C / min. The image shows that the phase change microcapsules maintained their independent core-shell structure without adhesion. The solvent resistance was tested according to GB / T 29170-2012, in which 3% (w / w) of the phase change microcapsules were placed in a 97% (w / w) oily solvent (No. 3 white oil) and rolled at 150°C for 16 hours. The rheological properties of the solution, including apparent viscosity, plastic viscosity, and dynamic shear force, were then measured using a six-speed rotational viscometer.

[0067] Example 2

[0068] This embodiment prepares a phase change microcapsule with an organic-inorganic hybrid wall material. The preparation process includes the following steps:

[0069] (1) Heat a 50mL three-necked flask to 70℃, weigh 100mL of polar solvent n-octane, 1.67g of interfacial grafting agent maleic anhydride, and 16.7g of phase change material mannitol, add them from the feed port of the reactor, and then proceed according to the method described in Example 1 to obtain the core material dispersion.

[0070] (2) Weigh 0.4g of the second organic radical monomer styrene, 0.26g of the first radical monomer KH570, 0.67g of the crosslinking agent divinylbenzene, and 0.47g of the initiator azobisisobutyronitrile and add them to the reaction vessel, and then proceed according to the method described in Example 1.

[0071] (3) Take the reactants into a container and let them stand for the material to separate into layers. Take the upper layer of polar solvent n-octane into a waste liquid tank. Add 8L of n-octane to the container for cleaning and filtration. When there is no liquid dripping out, clean and filter again with 3L of n-octane. The filter paper used for filtration has a pore size of 60μm. Pour out the filtered product and place it in a fume hood for ventilation and drying to obtain phase change microcapsules coated with organic-inorganic hybrid wall material.

[0072] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: a phase change temperature of 167.5℃; a latent heat of phase change of 230.12 J / g; and a particle size of 35-60 μm.

[0073] Example 3

[0074] This embodiment prepares a phase change microcapsule of an organic-inorganic hybrid wall material. Specifically, following the steps of Example 1, 50g of maleic anhydride and 500g of galactitol were weighed and placed in 3L of toluene; 12g of styrene, 20g of divinylbenzene, 8g of KH570, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, the microcapsules were prepared by washing, filtration, and drying.

[0075] In the organic-inorganic hybrid wall material-coated phase change microcapsules prepared in this embodiment, the phase change temperature of the organic-inorganic hybrid wall material-coated phase change microcapsules is 187.13℃; the latent heat of phase change of the organic-inorganic hybrid wall material-coated phase change microcapsules is 300.21J / g; and the particle size of the organic-inorganic hybrid wall material-coated phase change microcapsules is 15-60μm.

[0076] Example 4

[0077] This embodiment prepares a phase change microcapsule of an organic-inorganic hybrid wall material. Specifically, following the steps of Example 1, 50g of maleic anhydride and 500g of erythritol were weighed and placed in 3L of toluene; for the first addition, 12g of styrene, 20g of divinylbenzene, 8g of KH570, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, the microcapsules were prepared by washing, filtration, and drying.

[0078] In the organic-inorganic hybrid wall material-coated phase change microcapsules prepared in this embodiment, the phase change temperature of the organic-inorganic hybrid wall material-coated phase change microcapsules is 117.5℃; the latent heat of phase change of the organic-inorganic hybrid wall material-coated phase change microcapsules is 300.42J / g; and the particle size of the organic-inorganic hybrid wall material-coated phase change microcapsules is 15-40µm.

[0079] Example 5: Preparation of phase change microcapsules of an organic-inorganic hybrid wall material

[0080] Following the steps of Example 1, 50g of maleic anhydride and 500g of mannitol were weighed and placed in 3L of toluene; 12g of styrene, 20g of divinylbenzene, 8g of KH560, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, microcapsules were prepared by washing, filtration, and drying.

[0081] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: a phase change temperature of 167.25℃; a latent heat of phase change of 220.12 J / g; and a particle size of 35-60 μm.

[0082] Example 6: Preparation of phase change microcapsules of an organic-inorganic hybrid wall material

[0083] Following the steps of Example 1, 50g of maleic anhydride and 500g of mannitol were weighed and placed in 3L of toluene; 12g of styrene, 20g of divinylbenzene, 8g of KH550, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, microcapsules were prepared by washing, filtration, and drying.

[0084] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: a phase change temperature of 166.97℃; a latent heat of phase change of 224.45 J / g; and a particle size of 25-50 μm.

[0085] Example 7: Preparation of phase change microcapsules of an organic-inorganic hybrid wall material

[0086] Following the steps of Example 1, 50g of acrylic acid and 500g of mannitol were weighed and placed in 3L of toluene; 12g of styrene, 20g of divinylbenzene, 8g of KH550, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, microcapsules were prepared by washing, filtration, and drying.

[0087] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: a phase change temperature of 167.31℃; a latent heat of phase change of 227.34 J / g; and a particle size of 25-50 μm.

[0088] Example 8: Preparation of phase change microcapsules of an organic-inorganic hybrid wall material

[0089] Following the steps of Example 1, 50g of maleic anhydride and 500g of mannitol were weighed and placed in 3L of toluene; 12g of styrene, 20g of divinylbenzene, 8g of KH550, and 14g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, microcapsules were prepared by washing, filtration, and drying.

[0090] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: the phase change temperature is 169.76℃; the latent heat of phase change is 224.45 J / g; and the particle size is 25-50 μm.

[0091] Example 9: Preparation of phase change microcapsules of an organic-inorganic hybrid wall material

[0092] Following the steps of Example 1, 10g of maleic anhydride and 100g of xylitol were weighed and placed in 3L of toluene; 2.5g of styrene, 4g of divinylbenzene, 1.6g of KH550 and 3g of azobisisobutyronitrile were weighed and added to the reaction vessel; after reacting for 24 hours, microcapsules were prepared by washing, filtration and drying.

[0093] In this embodiment, the phase change microcapsules coated with organic-inorganic hybrid wall material have the following characteristics: a phase change temperature of 93.47℃; a latent heat of phase change of 200.84 J / g; and a particle size of 30-50 μm.

[0094] Example 10.

[0095] The same method as in Example 1 was used, and the operation steps of Example 1 were followed. The difference was that the amount of each raw material used was 10 times that in Example 1. In step (3), a centrifuge with a speed of 1500 rpm was used for separation (centrifugation time was 5 min), and vacuum drying at 65℃ was used (drying time was 24 h) to prepare phase change microcapsules coated with organic-inorganic wall material.

[0096] Comparative Example 1

[0097] The reaction steps were the same as in Example 1, except that the second organic monomer was used for all the reaction monomers. After 24 hours of reaction, the reaction was washed, filtered and dried to prepare phase change microcapsules.

[0098] Table 1. Raw materials used in each embodiment

[0099]

[0100] Table 2. Process conditions used in preparing phase change microcapsules in each embodiment

[0101]

[0102]

[0103] Table 3. Performance of the phase change microcapsules prepared in each example.

[0104] Example Phase transition temperature (°C) Latent heat of phase transition (J / g) Particle size (μm) 1 168.99 249.42 35-55 2 167.5 230.12 35-60 3 187.13 300.21 15-40 4 117.5 300.42 15-40 5 167.25 220.12 35-60 6 166.97 224.45 25-50 7 167.31 227.34 25-50 8 169.76 224.45 25-50 9 93.47 200.84 30-50 10 168.40 220 100-130

[0105] Table 4. Rheological properties of phase change microcapsules prepared in Example 1 and Comparative Example 1 in oily solvents.

[0106]

[0107] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing solvent-resistant phase change microcapsules coated with an organic-inorganic hybrid wall material, characterized in that, The method comprises the following steps: (1) adding an interfacial grafting agent and a phase change material to a polar solvent and performing a grafting reaction while stirring to prepare a core material dispersion liquid; (2) adding a first organic reaction monomer, a second organic reaction monomer, an initiator, and a crosslinking agent to the core material dispersion liquid to perform an in-situ polymerization reaction to prepare a reaction system containing phase change microcapsules, wherein the first organic reaction monomer is an inorganic component-containing organic reaction monomer, and the second organic reaction monomer is a pure organic reaction monomer; (3) washing, separating, and drying the reaction system to obtain a solid-phase product as the solvent-resistant phase change microcapsules.

2. The preparation method according to claim 1, characterized in that: the first organic reaction monomer is a silane coupling agent monomer, preferably the silane coupling agent monomer is at least one selected from vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, and 3-(trimethoxysilyl)propyl methacrylate; and / or the second organic reaction monomer is at least one selected from styrene, methylstyrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, tert-butyl acrylate, and isooctyl acrylate.

3. The preparation method according to claim 1 or 2, characterized in that: the interfacial grafting agent is at least one selected from maleic anhydride, acrylic acid, and methacrylic acid; the crosslinking agent is selected from unsaturated bond-containing crosslinking agents, preferably the crosslinking agent is selected from styrene derivatives and double bond-containing esters; more preferably, the styrene derivative is at least one selected from divinylbenzene, styrene ethyl trimethyl siloxane, and 1,3-diisopropenyl benzene; further preferably, the double bond-containing ester is at least one selected from ethylene glycol dimethacrylate, propylene glycol dimethyl acrylate, butylene glycol dimethacrylate, and ethylene glycol dimethacrylate; and / or the polar solvent is one selected from toluene, methanol, n-octane, n-butane, petroleum ether, cyclohexane, and n-pentane, preferably the solvent is toluene or n-octane.

4. The preparation method according to any one of claims 1 to 3, characterized in that: the initiator is an oil-soluble initiator; preferably, the oil-soluble initiator is an azo initiator or a peroxide initiator; more preferably, the azo initiator is at least one selected from azobis isobutyronitrile, azobis isobutyronitrile, dimethyl azobis isobutyrate, and azobis isobutyryl cyanamide; further more preferably, the peroxide initiator is at least one selected from dibenzoyl peroxide, dodecanoyl peroxide, dicumyl peroxide, diisopropyl peroxydicarbonate, benzoyl tert-butyl peroxide, and methyl ethyl ketone peroxide; further preferably, the azo initiator is azobis isobutyronitrile; further more preferably, the peroxide initiator is dibenzoyl peroxide.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The phase change material is a solid-liquid phase change material; The solid-liquid phase change material is a normal alkyl alcohol solid-liquid phase change material, a sugar alcohol solid-liquid phase change material, a polyether solid-liquid phase change material, and / or a mixed solid-liquid phase change material; Preferably, the normal alkyl alcohol solid-liquid phase change material is 1-tetradecanol and / or 1-octadecanol; the sugar alcohol solid-liquid phase change material is mannitol, xylitol, erythritol, and / or sorbitol; the polyether solid-liquid phase change material is polyethylene glycol and / or polybutylene glycol; and the mixed solid-liquid phase change material is a mixture of organic and inorganic phase change materials. More preferably, the sugar alcohol solid-liquid phase change material is mannitol, xylitol, erythritol, and / or sorbitol.

6. The preparation method of any one of claims 1 to 5, wherein: The interfacial grafting agent accounts for 0.1-30%, preferably 0.1-10%, of the mass of the polar solvent; The phase change material accounts for 1-50%, preferably 1-30%, of the mass of the polar solvent; The mass ratio of the first organic reaction monomer to the second organic reaction monomer is 1:0.1-100, preferably 1:0.1-50; The crosslinking agent accounts for 0.1-20%, preferably 0.1-10%, of the mass of the polar solvent; and / or The initiator accounts for 0.001-10%, preferably 0.001-1%, of the mass of the polar solvent; The total mass of the first organic reaction monomer and the second organic reaction monomer accounts for 0.001-10%, preferably 0.001-1%, of the mass of the polar solvent.

7. The preparation method of any one of claims 1 to 6, wherein: In the step (1), the grafting reaction is achieved by stirring, preferably at a stirring speed of 100-1000 rpm, preferably 100-500 rpm, for 100-500 min; In the step (2), the heating reaction is achieved by stirring after feeding, preferably at a stirring speed of 100-1000 rpm, for 10-70 h.

8. The preparation method of any one of claims 1 to 7, wherein: The steps (1) and (2) are independently carried out in an inert atmosphere, preferably nitrogen; and / or The temperature of the grafting reaction in the step (1) and the temperature of the in-situ polymerization reaction in the step (2) are independently 30-100℃, preferably 50-90℃; The separation mode in the step (3) is centrifugal separation and / or suction filtration separation, and the drying mode is atmospheric drying and / or vacuum drying.

9. The production method according to any one of claims 1 to 8, characterized by, In the step (3): The washing solution used in the washing accounts for 10%-95% of the total mass of the washed material; and / or The filter paper used in the suction filtration has a pore size of 30-500 μm; and the centrifugal separator has a rotation speed of 500-2000 r / min, preferably 1200-1800 r / min. The temperature of the vacuum drying oven is 35-100℃, preferably 45-80℃; the vacuum degree is -0.05MPa to -0.08MPa.

10. Phase change microcapsules prepared according to the process of any one of claims 1 to 9.

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