Dual-mode phase change thermal management film and preparation method and application thereof

Abstract

The invention relates to the technical field of thermal management, in particular to a dual-mode phase change thermal management film and a preparation method and application thereof, and the dual-mode phase change thermal management film comprises a phase change film, a photo-thermal film and a metal film arranged between the phase change film and the photo-thermal film. According to the double-sided flexible dual-mode phase change thermal management film formed by pasting the phase change film, the metal film and the photo-thermal film together, when the weather is hot, the phase change film faces upwards, and the effects of sunlight reflection and phase change cooling are achieved; when the weather is cold, the photo-thermal film faces upwards to absorb sunlight radiation and convert the sunlight radiation into heat, and meanwhile, the phase change film on the bottom layer stores the heat, so that the dual-mode phase change thermal management film can still play a role in heat preservation to a certain extent after sunlight disappears; the metal film arranged between the phase change film and the photo-thermal film can reflect radiation, assist the phase change film in sunlight reflection and increase the optical path of solar radiation in the photo-thermal film, so that the efficiency of the photo-thermal film is improved.

Description

Technical Field

[0001] The present invention relates to the field of thermal management technology, and in particular to a dual-mode phase-change thermal management film and a preparation method and application thereof. Background Art

[0002] Human bodies, buildings, outdoor equipment, etc. often need to operate within a suitable temperature range to ensure their normal functions and comfort. However, in summer, strong sunlight can heat outdoor objects to over 50°C, which not only seriously affects the comfort of human bodies and buildings, but also has an adverse effect on the safety of various equipment. On the contrary, in winter, weak sunlight cannot provide enough heat for outdoor objects, resulting in low temperatures, which forms a sharp contrast with the lower temperature, thus affecting the use effect and performance.

[0003] At present, thermal management is mainly achieved through active heating / cooling. Active thermal management equipment is large in size, expensive, high in power consumption, and difficult to maintain. It can neither meet the needs of flexible thermal management nor increase carbon emissions. Passive cooling includes installing cooling fins and heat sinks, which can only meet the needs of single cooling, but it is difficult to achieve long-term heat preservation. There is currently no universal technical solution that can achieve dual-mode temperature control for heating and cooling.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a dual-mode phase change thermal management film and a preparation method and application thereof, aiming to solve the problem that the existing thermal management equipment cannot achieve dual-mode temperature regulation of heating and cooling.

[0006] The technical solution of the present invention is as follows:

[0007] A dual-mode phase-change heat management film comprises a phase-change film, a photothermal film and a metal film arranged between the phase-change film and the photothermal film.

[0008] The dual-mode phase-change heat management film, wherein the raw materials for preparing the phase-change film include, by mass, 4-8 parts of two-component heat-curing transparent silicone rubber and 3-5 parts of phase-change material.

[0009] The dual-mode phase-change heat management film, wherein the phase-change material is selected from one or more of n-octadecane, n-eicosane, n-docosane, and polyethylene glycol.

[0010] The dual-mode phase-change thermal management film, wherein the raw materials for preparing the photothermal film include, by weight: 90-110 parts of two-component heat-curing transparent silicone rubber and 1-3 parts of photothermal material.

[0011] The dual-mode phase-change thermal management film, wherein the photothermal material is selected from one or more of carbon nanotubes, graphene, and carbon black.

[0012] The dual-mode phase-change thermal management film, wherein the thickness of the phase-change film is 2-4 mm; and / or the thickness of the photothermal film is 2-4 mm; and / or the thickness of the metal film is 10-20 μm.

[0013] The dual-mode phase-change thermal management film, wherein the metal film comprises one of aluminum foil, tin foil and copper foil.

[0014] A method for preparing a dual-mode phase change thermal management film comprises the following steps:

[0015] The two-component heat-curing transparent silicone rubber is mixed with the phase change material, and after curing, a phase change film is obtained;

[0016] The two-component heat-curing transparent silicone rubber is mixed with the photothermal material, and after curing, a photothermal film is obtained;

[0017] The phase change film, the metal film and the photothermal film are bonded and fixed from top to bottom to obtain a dual-mode phase change thermal management film.

[0018] The method for preparing the dual-mode phase-change thermal management film, wherein the temperature of the curing treatment is 60-120° C., and the time of the curing treatment is 2-4 hours.

[0019] Application of a dual-mode phase change thermal management film in a thermal management system.

[0020] Beneficial effects: The present invention provides a dual-mode phase-change thermal management film and its preparation method and application. The dual-mode phase-change thermal management film includes: a phase-change film, a photothermal film, and a metal film disposed between the phase-change film and the photothermal film. The present invention utilizes the temperature regulating ability of the phase-change film. When the temperature is low, the phase-change material exists in the flexible phase-change film in the form of micron-sized particles. Its micron morphology can produce Rayleigh and Mie scattering, and the reflectivity of sunlight is as high as 73.53%. When exposed to sunlight, the phase-change material melts and absorbs heat within a period of time. When the temperature drops, the phase-change material solidifies and releases heat. The photothermal film has the ability to convert light into heat. When the weather is cold, it can fully utilize solar radiation to convert into heat, which plays a role in heating and keeping the covered object warm. The double-sided flexible dual-mode phase change thermal management film formed by pasting the phase change film, metal film and photothermal film together has the phase change film facing upward when the weather is hot, so as to reflect sunlight and cool down by phase change; when the weather is cold, the photothermal film is facing upward to absorb solar radiation and convert it into heat, while the underlying phase change film stores heat, so that the dual-mode phase change thermal management film can still play a heat-insulating role to a certain extent after the sunlight disappears; the metal film arranged between the phase change film and the photothermal film can reflect radiation, assist the phase change film in reflecting sunlight, and increase the optical path of solar radiation in the photothermal film, thereby improving the efficiency of the photothermal film. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a dual-mode phase change thermal management film of the present invention;

[0022] Figure 2 This is a temperature curve diagram of the outdoor thermal management experiment of the dual-mode phase change thermal management film in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a dual-mode phase change thermal management film and a preparation method and application thereof. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0025] like Figure 1As shown, the present invention provides a dual-mode phase-change heat management film, comprising: a phase-change film 10 , a photothermal film 20 , and a metal film 30 disposed between the phase-change film 10 and the photothermal film 20 .

[0026] In this embodiment, the phase change film has the ability to regulate temperature. When the temperature is low, the phase change material exists in the flexible phase change film in the form of micron-sized particles. Its micron morphology can produce Rayleigh and Mie scattering, and the reflectivity of sunlight is as high as 73.53%. When exposed to sunlight, the phase change material melts and absorbs heat within a period of time. When the temperature drops, the phase change material solidifies and releases heat. The photothermal film has the ability to convert light into heat. When the weather is cold, it can make full use of solar radiation to convert it into heat, thereby heating and insulating the covered object. The double-sided flexible dual-mode phase change thermal management film formed by pasting the phase change film, metal film and photothermal film together has the phase change film facing upward when the weather is hot, so as to reflect sunlight and cool down by phase change; when the weather is cold, the photothermal film is facing upward to absorb solar radiation and convert it into heat, while the underlying phase change film stores heat, so that the dual-mode phase change thermal management film can still play a heat-insulating role to a certain extent after the sunlight disappears; the metal film arranged between the phase change film and the photothermal film can reflect radiation, assist the phase change film in reflecting sunlight, and increase the optical path of solar radiation in the photothermal film, thereby improving the efficiency of the photothermal film.

[0027] Specifically, the phase change film is milky white at room temperature. When the phase change film is placed upward, it has good sunlight reflectivity and can effectively reduce the temperature increase of the covering caused by the photothermal effect; when the temperature rises to the phase change temperature point, the phase change material in the phase change film melts and absorbs heat, effectively reducing the temperature of the covering. When the phase change film is placed downward, it can accumulate the heat converted by the photothermal film and release it when the sunlight intensity decreases to achieve a heat preservation effect. The photothermal film has excellent photothermal conversion ability. When placed upward, it can convert sunlight into heat for heat preservation of the covering; and the metal film can reflect radiation, and assist the phase change film in reflecting sunlight, and increase the optical path of solar radiation in the photothermal film, thereby improving the efficiency of the photothermal film. The phase change film and the photothermal film are arranged on both sides of the metal film using a sandwich structure. When the weather is hot, the phase change film is upward to cover the building or equipment that needs thermal management, and when the weather is cold, the photothermal film is upward to cover.

[0028] In some embodiments, the raw materials for preparing the phase change film include, by mass, 4-8 parts of two-component heat-curing transparent silicone rubber and 3-5 parts of phase change material. The micro-nano properties of the phase change material and the transparent flexible silicone rubber that can be miscible with the phase change material above and below the phase change temperature are used to change the light and heat management and thermal management. Below the phase change temperature, the phase change material and the silicone rubber undergo phase separation to form micron-sized spheres, which have a strong reflective effect on sunlight, and the phase change material melts at a certain temperature to absorb heat, thereby playing a role in phase change cooling.

[0029] In a preferred embodiment, the raw materials for preparing the phase change film include, by mass, 5 parts of two-component heat-curing transparent silicone rubber and 3-5 parts of phase change material. The two-component heat-curing transparent silicone rubber includes component A and component B, wherein component A is a silicone rubber prepolymer and component B is a curing agent. The phase change film prepared by using the two-component heat-curing transparent silicone rubber and the phase change material is milky white and flexible at room temperature, so that the phase change film has phase change temperature regulation capability. More preferably, the raw materials for preparing the phase change film include, by mass, 5 parts of two-component heat-curing transparent silicone rubber and 4 parts of phase change material.

[0030] In some embodiments, the phase change material is selected from but not limited to one or more of n-octadecane, n-eicosane, n-docosane, and polyethylene glycol. A specific oily phase change material or a mixed phase change material compounded from at least two oily phase change materials can be selected according to the actual required phase change temperature. The phase change point of n-octadecane is 25°C, the phase change point of n-eicosane is 36°C, and the phase change point of n-docosane is 45°C.

[0031] Specifically, the phase change material may be a combination of, but not limited to, one or more of n-octadecane, n-eicosane, n-docosane, polyethylene glycol, and a transparent flexible material.

[0032] In some embodiments, the raw materials for preparing the photothermal film include, by weight: 90-110 parts of two-component heat-curing transparent silicone rubber and 1-3 parts of photothermal material.

[0033] In a preferred embodiment, the raw materials for preparing the photothermal film include, by mass, 100 parts of two-component heat-curing transparent silicone rubber and 1-3 parts of photothermal material; more preferably, the raw materials for preparing the photothermal film include, by mass, 100 parts of two-component heat-curing transparent silicone rubber and 2 parts of photothermal material. The photothermal film prepared according to the above mass fractions has excellent photothermal conversion ability. When placed upward, it can convert sunlight into heat for the insulation of the covered object.

[0034] In some embodiments, the photothermal material is selected from but not limited to one or more black photothermal materials such as carbon nanotubes, graphene, and carbon black. The above photothermal materials can absorb solar radiation and convert it into heat, while allowing the phase change film on the other side to store heat, so that the double-sided flexible dual-mode phase change thermal management film can continue to release heat and play a role in heat preservation at night when there is no sunlight.

[0035] In some embodiments, the thickness of the phase change film is 2-4 mm; and / or the thickness of the photothermal film is 2-4 mm; and / or the thickness of the metal film is 10-20 μm. The dual-mode phase change thermal management film prepared within the above thickness range has thin thickness, good flexibility and good temperature regulation ability, realizing the dual-mode temperature regulation function of heating and cooling.

[0036] In a preferred embodiment, the thickness of the phase change film is 2.5 mm; and / or the thickness of the photothermal film is 2.5 mm; and / or the thickness of the metal film is 20 μm.

[0037] In some embodiments, the metal film includes but is not limited to one of aluminum foil and tin foil. The above metal film has low cost, good metal ductility, and is not easy to break; and this type of metal film can reflect solar radiation, assist the phase change film in reflecting sunlight, and increase the optical path of solar radiation in the photothermal film, thereby improving the efficiency of the photothermal film.

[0038] In addition, the present invention also provides a method for preparing a dual-mode phase change thermal management film, comprising the steps of:

[0039] Step S10: mixing the two-component heat-curing transparent silicone rubber with the phase change material, and obtaining a phase change film after curing;

[0040] Step S20: mixing the two-component heat-curing transparent silicone rubber with the photothermal material, and obtaining a photothermal film after curing;

[0041] Step S30: bonding and fixing the phase change film, the metal film and the photothermal film from top to bottom to obtain a dual-mode phase change thermal management film.

[0042] In this embodiment, the photothermal management and thermal management are realized by using the micro-nano optical property changes of the phase change material and the two-component heat-curing transparent silicone rubber that can be miscible with the phase change material above and below the phase change temperature; below the phase change temperature, the phase change material and the silicone rubber undergo phase separation to form micron-sized balls, which have a strong reflective effect on sunlight; and the phase change material melts at a certain temperature to absorb heat, thereby playing a role in phase change cooling. Then, the photothermal film obtained by mixing the two-component heat-curing transparent silicone rubber with the photothermal material and curing it has the ability to convert light into heat. When the weather is cold, it can make full use of the solar radiation to convert into heat, which plays a role in heating and keeping the covered object warm. Finally, the phase change film, the metal film and the photothermal film are sequentially bonded and fixed to obtain a dual-mode phase change thermal management film. By determining that one side of the phase change film and the photothermal film is facing up according to the sunshine conditions during use, the thermal management film can realize the dual-mode temperature control function of heating and cooling.

[0043] In some embodiments, the curing temperature is 60-120° C., and the curing time is 2-4 hours. The phase change material and the two-component heat-curing transparent silicone rubber, and the photothermal material and the two-component heat-curing transparent silicone rubber are cured by the curing process to obtain a flexible phase change film and a photothermal film.

[0044] In a preferred embodiment, the curing temperature is 90° C. and the curing time is 3 hours.

[0045] In some embodiments, the phase change film, the metal film and the photothermal film are bonded together including but not limited to using glue or rivets for bonding and fixing.

[0046] In some embodiments, in step S10 and step S20, component A of the two-component heat-curing transparent silicone rubber is first mixed with the phase change material and the photothermal material, respectively, and then curing agents are added respectively. After stirring evenly and curing treatment, a phase change film and a photothermal film are obtained respectively.

[0047] In addition, the present invention also provides an application of a dual-mode phase-change heat management film in a heat management system.

[0048] In this embodiment, the dual-mode phase-change thermal management film is applied in a thermal management system, and the dual-mode phase-change thermal management film can be flipped to determine whether the phase-change film is facing upward or the photothermal film is facing upward according to the solar radiation conditions. When the weather is hot and the phase-change film is facing upward, when it is exposed to sunlight, the phase-change material melts and absorbs heat within a period of time, and when the temperature drops, the phase-change material solidifies and releases heat; the photothermal film has the ability to convert sunlight into heat, and when the weather is cold, it can fully utilize solar radiation to convert into heat, which plays a role in heating and keeping the covered object warm, while allowing the bottom phase-change film to store heat, so that the double-sided flexible thermal management film can continue to release heat and play a role in keeping warm at night when there is no sunlight.

[0049] The following examples are further given to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention.

[0050] Example 1

[0051] This embodiment provides a dual-mode phase change thermal management film, and the preparation steps specifically include:

[0052] 1) Preparation of phase change film

[0053] Take 5 parts of two-component heat-curing transparent silicone rubber and 4 parts of phase change material n-eicosane; heat component A (silicone rubber prepolymer) of the two-component heat-curing transparent silicone rubber and n-eicosane to 35-45°C and fully stir to dissolve until the mixture becomes clear, then add the curing agent (component B) and stir well, pour into a mold, and cure at 90°C for 3 hours to obtain a phase change film with a thickness of about 2.5 mm and a milky white color at room temperature.

[0054] 2) Preparation of photothermal film

[0055] Take 100 parts of two-component heat-curing transparent silicone rubber and 2 parts of carbon nanotubes; stir component A (silicone rubber prepolymer) of the two-component heat-curing transparent silicone rubber and the carbon nanotubes at high speed until there are no particles, add a curing agent (component B) and cure at 90°C for 3 hours to obtain a photothermal film with a thickness of about 2.5 mm.

[0056] 3) Assembly of dual-mode phase change thermal management film

[0057] The phase change film, aluminum foil, and photothermal film are bonded and fixed with glue in the order from top to bottom to obtain a dual-mode phase change thermal management film.

[0058] In this embodiment, when the dual-mode phase change thermal management film is in use, the phase change film or the photothermal film is selected to face upward according to the weather or solar radiation conditions; when the weather is hot, the phase change film is faced upward to cover the building or equipment that needs thermal management, and when the weather is cold, the photothermal film is faced upward to cover the building or equipment that needs thermal management.

[0059] In order to test the thermal management ability of the dual-mode phase change thermal management film prepared in this embodiment in real applications, the dual-mode phase change thermal management film was placed outdoors for testing. A thermocouple was set at the bottom of the film sample to monitor the temperature. The experiment started at about 11 o'clock in the morning and continued until the evening, covering the afternoon with strong sunlight and temperature and the evening without sunlight, in order to evaluate the dual-mode phase change thermal management film's ability to regulate temperature in hot and cold environments during the day. The ambient temperature and sunlight intensity near the test point were also measured as a reference.

[0060] like Figure 2 As shown in the figure, due to the photothermal effect of the photothermal film, the temperature of the dual-mode phase-change thermal management film with the photothermal side facing upward (heating state) rose rapidly shortly after the experiment began, reaching a peak temperature about 40 minutes after the experiment began, which was significantly higher than the blank sample, indicating that the dual-mode phase-change thermal management film in the heating state has excellent photothermal capacity, which can effectively increase the temperature of the covered substrate and save heating costs; while the temperature of the dual-mode thermal management film with the phase-change film facing upward (cooling state) was significantly lower than that of the blank sample in the first 3000 seconds, indicating that the dual-mode thermal management film in the cooling state has the ability to slow down the temperature rise and can reduce the temperature of the covered object. 3 hours before the end of the experiment, due to the lack of sunlight, the temperature of the blank sample dropped rapidly, while the n-eicosane inside the dual-mode phase-change thermal management film in the heating and cooling states released heat due to phase change due to the proximity to the phase change temperature, making its temperature drop slower than that of the blank sample, providing a temperature buffer effect for the covering. Therefore, it is proved that the dual-mode phase change thermal management film can provide the covered object with light and heat insulation and phase change to slow down the temperature drop rate in the heating state, and can provide the covered object with the ability to suppress the rapid rise and fall of temperature in the cooling state. Based on the above conclusions, the dual-mode phase change thermal management film prepared in this embodiment has the ability to intelligently control the temperature of the covered object.

[0061] In summary, the present invention provides a dual-mode phase-change thermal management film and its preparation method and application. The dual-mode phase-change thermal management film includes: a phase-change film, a photothermal film, and a metal film disposed between the phase-change film and the photothermal film. The present invention utilizes the temperature regulating ability of the phase-change film. When the temperature is low, the phase-change material exists in the flexible phase-change film in the form of micron-sized particles. Its micron morphology can produce Rayleigh and Mie scattering, and the reflectivity of sunlight is as high as 63%. When exposed to sunlight, the phase-change material melts and absorbs heat within a period of time. When the temperature drops, the phase-change material solidifies and releases heat. The photothermal film has the ability to convert light into heat. When the weather is cold, it can fully utilize solar radiation to convert into heat, which plays a role in heating and keeping the covered object warm. The double-sided flexible dual-mode phase change thermal management film formed by pasting the phase change film, metal film and photothermal film together has the phase change film facing upward when the weather is hot, so as to reflect sunlight and cool down by phase change; when the weather is cold, the photothermal film is facing upward to absorb solar radiation and convert it into heat, while the underlying phase change film stores heat, so that the dual-mode phase change thermal management film can still play a heat-insulating role to a certain extent after the sunlight disappears; the metal film arranged between the phase change film and the photothermal film can reflect radiation, assist the phase change film in reflecting sunlight, and increase the optical path of solar radiation in the photothermal film, thereby improving the efficiency of the photothermal film.

[0062] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A dual-mode phase change thermal management film, characterized in that: include: A phase change film, a photothermal film and a metal film arranged between the phase change film and the photothermal film.

2. The dual-mode phase change thermal management film according to claim 1, characterized in that: The raw materials for preparing the phase change film include, by weight: 4-8 parts of two-component heat-curing transparent silicone rubber and 3-5 parts of phase change material.

3. The dual-mode phase change thermal management film according to claim 2, characterized in that: The phase change material is selected from one or more of n-octadecane, n-eicosane, n-docosane and polyethylene glycol.

4. The dual-mode phase change thermal management film according to claim 1, characterized in that: The raw materials for preparing the photothermal film include, by weight: 90-110 parts of two-component heat-curing transparent silicone rubber and 1-3 parts of photothermal material.

5. The dual-mode phase change thermal management film according to claim 4, characterized in that: The photothermal material is selected from one or more of carbon nanotubes, graphene, and carbon black.

6. The dual-mode phase change thermal management film according to claim 1, characterized in that: The thickness of the phase change film is 2-4 mm; and / or the thickness of the photothermal film is 2-4 mm; and / or the thickness of the metal film is 10-20 μm.

7. The dual-mode phase change thermal management film according to claim 1, characterized in that: The metal film includes one of aluminum foil, tin foil and copper foil.

8. A method for preparing a dual-mode phase change thermal management film according to any one of claims 1 to 7, characterized in that: Includes steps: The two-component heat-curing transparent silicone rubber is mixed with the phase change material, and after curing, a phase change film is obtained; The two-component heat-curing transparent silicone rubber is mixed with the photothermal material, and after curing, a photothermal film is obtained; The phase change film, the metal film and the photothermal film are bonded and fixed from top to bottom to obtain a dual-mode phase change thermal management film.

9. The method for preparing the dual-mode phase change thermal management film according to claim 8, characterized in that: The curing temperature is 60-120° C., and the curing time is 2-4 hours.

10. Use of the dual-mode phase change heat management film according to any one of claims 1 to 7 in a heat management system.

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