A temperature and humidity control material, a preparation method thereof and application thereof

Abstract

The application discloses a temperature and humidity adjusting material and a preparation method and application thereof. The preparation method of the temperature and humidity adjusting material comprises the following steps: (1) uniformly mixing inorganic hydrated salt phase change material, a nucleating agent and water, stirring under the condition of 40-55 DEG C for 10-20 min, then adding porous material, and continuously stirring for 60-120 min to obtain a composite phase change material; (2) cooling the composite phase change material to room temperature, and then pressing the composite phase change material into a phase change plate material; (3) using inorganic mineral material as a humidity adjusting material, and respectively pressing the humidity adjusting material into a first humidity adjusting plate material and a second humidity adjusting plate material; and (4) sequentially assembling the first humidity adjusting plate material, the phase change plate material and the second humidity adjusting plate material by using a building structure adhesive, and coating the first humidity adjusting plate material, the phase change plate material and the second humidity adjusting plate material with an aluminum foil to obtain a temperature and humidity adjusting plate material. The material prepared by the application has good temperature adjusting performance and humidity controlling performance, and the heat storage performance changes little under high humidity, and is suitable for being used in a greenhouse shed with high air relative humidity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of temperature and humidity control materials, in particular to a temperature and humidity control material and a preparation method and application thereof. BACKGROUND

[0002] Greenhouse is a production method of modern agricultural technology, and plays an important role in modern agricultural production. In the greenhouse, high temperature can increase the evaporation in the greenhouse, resulting in dry seedlings, and also can cause flower and fruit drop, and low temperature can cause crop frost damage. Therefore, unsuitable temperature can reduce the yield and quality of crops. Not only temperature is an important factor for crop growth in the greenhouse, but also humidity is an important factor for crop growth in the greenhouse. In the greenhouse, high humidity can cause insufficient light, affect the growth and development of crops, and also can cause a large number of harmful bacteria to breed, resulting in damage to crops; low humidity can hinder the photosynthesis of crops and affect the development of fruits.

[0003] In the greenhouse, the traditional temperature and humidity control measure is ventilation. For greenhouse production, this measure has the disadvantage of being greatly affected by seasons and weather. At the same time, if the area of the greenhouse is large, it will take a long time and the effect is not obvious, especially in the central area of the greenhouse. Once the ventilation and exhaust system fails, it is difficult to control the temperature and humidity, and the long-time ventilation and exhaust will have a huge impact on the temperature fluctuation of the greenhouse. Even if some active temperature and humidity control measures are used, the cost and labor will also increase. Therefore, it is urgent to seek green and economic temperature and humidity control measures for the greenhouse.

[0004] In the process of phase change, the phase change material can absorb or release heat energy at a constant temperature, so as to adjust the temperature fluctuation in the greenhouse and reduce the heat loss. However, at present, organic phase change materials such as paraffin and dodecanol are mainly used, but the organic phase change materials have high cost, are flammable, and some materials have toxic effect, which are not suitable for the greenhouse for crop growth. The moisture absorption material is a common functional material, which can rely on its own pore structure to absorb water in the greenhouse and release water at low humidity, so as to control the humidity in the greenhouse. The heat and humidity in the greenhouse environment are coupled in the natural state, and the single phase change material or moisture absorption material can only control the temperature or humidity respectively. In order to control the heat and humidity in the greenhouse simultaneously, it is urgent to develop a temperature and humidity control material. SUMMARY

[0005] The primary purpose of the present application is to overcome the shortcomings and deficiencies of the prior art, and to provide a preparation method of a temperature and humidity control material.

[0006] Another purpose of the present application is to provide a temperature and humidity control material prepared by the method.

[0007] Still another object of the present application is to provide the application of the temperature and humidity control material.

[0008] The object of the present application is achieved by the following technical solutions:

[0009] A preparation method of a temperature and humidity control material, comprising the following steps:

[0010] (1) uniformly mixing inorganic hydrated salt phase change material, nucleating agent and water, stirring at 40-55℃ for 10-20min, then adding porous material, continuing to stir at 40-55℃ for 60-120min to obtain composite phase change material; wherein the composite phase change material comprises the following raw materials in percentage by weight: inorganic hydrated salt phase change material 50-80%, deionized water 0-20%, nucleating agent 0-6%, porous material 20-50%;

[0011] (2) cooling the composite phase change material obtained in step (1) to room temperature, then pressing it into phase change plate material;

[0012] (3) using inorganic mineral material as humidity control material, pressing it into first humidity control plate material and second humidity control plate material;

[0013] (4) sequentially layering and combining the first humidity control plate material, phase change plate material and second humidity control plate material to form a sandwich structure, and using building structure adhesive and aluminum foil to coat the bottom surface and side surface thereof to obtain temperature and humidity control plate material, i.e. the temperature and humidity control material.

[0014] Preferably, the inorganic hydrated salt phase change material in step (1) is inorganic hydrated salt phase change material with phase change temperature of 15-40℃ and phase change latent heat of 80-250J / g.

[0015] Preferably, the inorganic hydrated salt phase change material in step (1) is hydrated salt compound or inorganic hydrated salt phase change material composed of hydrated salt compound and other compounds; wherein the other compounds are at least one of sodium chloride, potassium chloride, urea and formamide, etc., which can be used to adjust the phase change temperature of inorganic hydrated salt, such as sodium acetate trihydrate-urea which can be used to compose the required inorganic hydrated salt phase change material.

[0016] Preferably, the hydrated salt compound is at least one of dodecahydrate disodium hydrogen phosphate, trihydrate disodium hydrogen phosphate, tenhydrate sodium carbonate, hexahydrate magnesium chloride, sodium acetate trihydrate, tenhydrate sodium sulfate, hexahydrate zinc nitrate, hexahydrate magnesium nitrate, pentahydrate sodium thiosulfate, octahydrate barium hydroxide, dodecahydrate aluminum ammonium sulfate, dodecahydrate aluminum potassium sulfate, etc.

[0017] Further preferably, the inorganic hydrated salt phase change material is at least one of dodecahydrate disodium hydrogen phosphate and trihydrate disodium hydrogen phosphate.

[0018] Preferably, the nucleating agent in step (1) is at least one of sodium silicate nonahydrate, strontium chloride hexahydrate, aluminum oxide, sodium pyrophosphate decahydrate, fumed silica, borax, strontium carbonate, disodium hydrogen phosphate dodecahydrate, expanded graphite, etc.

[0019] More preferably, the nucleating agent in step (1) is at least one of sodium silicate nonahydrate and strontium chloride hexahydrate.

[0020] Preferably, the porous material in step (1) is one of micro-powder silica gel, sepiolite, silicon dioxide, expanded perlite, activated carbon, expanded vermiculite, expanded graphite, water-absorbing resin, carbon nitride, diatomite, montmorillonite, foamed aluminum, foamed copper, silicon nitride, aerogel, and boron nitride foam, etc.

[0021] Preferably, the silicon dioxide includes fumed silica, which is commercially available from Shandong Yousuo Chemical Technology Co., Ltd.

[0022] Preferably, the aerogel includes at least one of silicon aerogel, boron nitride aerogel, metal aerogel, polymer aerogel, biomass aerogel, graphene aerogel, and cellulose aerogel, etc.

[0023] More preferably, the porous material in step (1) is micro-powder silica gel.

[0024] Preferably, the composite phase change material in step (1) includes the following raw materials in terms of weight percentage: hydrated salt phase change material 62-70%, deionized water 0-10%, nucleating agent 2-5%, and porous material 20-30%.

[0025] Preferably, the temperature of the stirring in step (1) is 48-50°C.

[0026] Preferably, the time of the stirring in step (1) is 15-20 min.

[0027] Preferably, the time of the continued stirring in step (1) is 60-90 min.

[0028] Preferably, the pressure value of the pressing in step (2) is no more than 2 MPa.

[0029] Preferably, the density of the phase change plate material in step (2) is 750-900 kg / m 3 .

[0030] Further preferably, the density of the phase change plate material in step (2) is 800-900 kg / m 3 .

[0031] Still further preferably, the density of the phase change plate material in step (2) is 815 kg / m 3 .

[0032] The shape and size of the phase change plate in step (2) can be pressed according to the actual size, including cylinder, cube, cuboid, etc.

[0033] Preferably, the size of the phase change plate in step (2) is: length 450mm-600mm, width 350mm-600mm, thickness (height) 8mm-15mm.

[0034] More preferably, the size of the phase change plate in step (2) is: length 450mm, width 350mm, thickness (height) 8mm (450mm x 350mm x 8mm).

[0035] Preferably, the inorganic mineral material in step (3) is at least one of diatomite, bentonite, sepiolite, zeolite, vermiculite, attapulgite, plant fiber and allophane, etc.

[0036] Preferably, the sepiolite can be purchased from Guangzhou Tobi New Materials Co., Ltd.

[0037] Preferably, the attapulgite can be purchased from Guangzhou Tobi New Materials Co., Ltd.

[0038] More preferably, the inorganic mineral material in step (3) is at least one of diatomite and bentonite.

[0039] Preferably, the pressure value of the pressing in step (3) is 6-12MPa.

[0040] The shape and size of the first and second humidity control plates in step (3) can be pressed according to the actual size, including cylinder, cube, cuboid, etc.

[0041] Preferably, the density of the first and second humidity control plates in step (3) is 1200-1400kg / m 3 .

[0042] Further preferably, the density of the first and second humidity control plates in step (3) is 1300-1400kg / m 3 .

[0043] Still further preferably, the density of the first and second humidity control plates in step (3) is 1361kg / m 3 .

[0044] Preferably, the first humidity regulating board and the second humidity regulating board in step (3) have a size of 450mm-600mm in length, 350mm-600mm in width and 2mm-15mm in thickness (height).

[0045] Further preferably, the first humidity regulating board and the second humidity regulating board in step (3) have a size of 450mm in length, 350mm in width and 2mm-8mm in thickness (height).

[0046] Still further preferably, the first humidity regulating board and the second humidity regulating board have different thicknesses (same density), and the thickness of the first humidity regulating board is twice that of the second humidity regulating board.

[0047] Preferably, the coating thickness of the building structural adhesive in step (4) is 0.1mm.

[0048] Preferably, the greater the thickness of the humidity regulating board in step (4), the better the moisture absorption amount, and the better the improvement on the phase change material.

[0049] A temperature and humidity regulating material prepared by the method of any one of the above.

[0050] Application of the temperature and humidity regulating material in a greenhouse.

[0051] Preferably, the greenhouse is a greenhouse with high relative humidity.

[0052] More preferably, the greenhouse is a greenhouse with relative humidity higher than 75%.

[0053] The present application has the following advantages and effects relative to the prior art:

[0054] 1. The present application uses inorganic hydrated salt phase change material and inorganic mineral material to develop a composite material with temperature and humidity regulating performance, which can passively regulate the temperature and humidity in a greenhouse, reduce the heat and humidity load in the greenhouse, and thus meet the growth of crops in suitable temperature and humidity.

[0055] 2. Since conventional inorganic phase change material has the advantages of wide source, low price and non-flammability, but has the problem of water loss and absorption in natural environment, the present application combines humidity regulating material and inorganic hydrated salt, and the water transfer of the two interacts, the humidity regulating material with certain moisture absorption amount can improve the water loss and absorption problem of inorganic hydrated salt (the thermal performance of inorganic hydrated salt will decrease after water loss), and thus a composite material with temperature and humidity regulating performance can be prepared.

[0056] 3、The temperature and humidity regulating material prepared by the application has good temperature regulating performance and humidity controlling performance, and the heat storage performance changes little under high humidity, and is suitable for use in a greenhouse (such as cucumber and celery planting) with high relative humidity, and can realize the effect of simultaneously regulating the temperature and humidity in the greenhouse.

[0057] 4、The temperature and humidity regulating material prepared by the application has the performance of simultaneously regulating temperature and humidity under natural conditions, and solves the single performance of phase change materials or humidity regulating materials. The inorganic hydrated salt phase change material with high energy storage density is used, the supercooling defect of the inorganic hydrated salt phase change material is solved by adding a nucleating agent, and the liquid leakage defect of the inorganic hydrated salt phase change material in the phase change process is solved by being combined with the porous material. Compared with organic phase change materials, the inorganic hydrated salt phase change material selected by the application has the advantages of high latent heat, non-flammability, low price and easy availability, and is more popular in actual greenhouse environments.

[0058] 5、The temperature and humidity regulating plate with a sandwich structure is made by using the building structural adhesive to sandwich the composite phase change material between two humidity regulating material plates. The enthalpy change of the phase change material is small under high humidity. In addition, the interaction between the humidity regulating material and the phase change material helps to improve the heat storage performance of the phase change material. The material can be applied to a greenhouse to simultaneously passively regulate the heat and humidity in the greenhouse, so as to achieve the purpose of passively regulating the temperature and humidity and reduce the economic cost.

[0059] 6、The temperature and humidity regulating material prepared by the application can regulate the environment in the greenhouse, has low price, is non-toxic, does not corrode the greenhouse maintenance structure, and has a simple preparation method. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 is a cross-sectional schematic view of the temperature and humidity regulating material prepared by the embodiment 1 of the application (in the figure, 1: first humidity regulating plate; 2: phase change plate; 3: second humidity regulating plate).

[0061] Figure 2 is a DSC curve diagram of the single composite phase change plate and the temperature and humidity regulating plate prepared by the embodiment 1 of the application under different relative humidities and placed for different days; wherein, (a) is the DSC curve of the single composite phase change plate under 75% relative humidity and placed for different days; (b) is the DSC curve of the temperature and humidity regulating plate (sandwich structure composed of diatomite and composite phase change material) saturated with moisture under 75% relative humidity and placed for different days after being saturated with moisture under 97% relative humidity; (c) is the DSC curve of the temperature and humidity regulating plate (sandwich structure composed of diatomite and composite phase change material) placed for different days under 97% relative humidity after being saturated with moisture under 97% relative humidity. DETAILED DESCRIPTION

[0062] The application will be further described in connection with the following examples. These examples do not limit the scope of the application. Unless otherwise stated, the reagents, methods and apparatus used in the present application are those conventional in the art. The experimental procedures in the following examples were carried out under conventional experimental conditions unless otherwise stated. Unless otherwise stated, the reagents and starting materials used in the present application are commercially available.

[0063] The micropowder silica gel used in the examples of the present application was purchased from Shandong Yousuo Chemical Technology Co., Ltd. The diatomite was purchased from Hebei Huakai Environmental Protection Material Co., Ltd.

[0064] Example 1

[0065] A temperature and humidity control material and a preparation process thereof, and the specific steps are as follows:

[0066] a. Put deionized water, inorganic hydrated salt phase change material disodium hydrogen phosphate dodecahydrate, and nucleating agent sodium silicate nonahydrate into a glass bottle, then place the glass bottle in a 48℃ water bath for stirring, and the stirring time is 15 min to obtain a mixed solution; then directly add porous material (micropowder silica gel) into the mixed solution, and then intermittently stir at a temperature of 48℃ for 90 min to obtain a composite phase change material; wherein the composite phase change material comprises the following raw materials in terms of weight percentage: inorganic hydrated salt phase change material 62%, deionized water 5%, nucleating agent 3%, and porous material 30%;

[0067] b. Cool the prepared composite phase change material to room temperature, and then use a mold to press the composite phase change material into a phase change plate material with a certain size (the size of the phase change plate material: a column with a diameter of 20 mm and a thickness of 4 mm), wherein the phase change plate material is obtained by pressing at room temperature using a manual hydraulic tablet press (the mold used in the experiment is a cylinder with a diameter of 20 mm), and the density of the plate material is 815 kg / m 3 , and the pressure value is not more than 2 MPa, and the thickness of the phase change plate material is 4 mm;

[0068] c. Select inorganic mineral material (diatomite) with good moisture absorption performance as a humidity control material, and use a mold to press the humidity control material into two humidity control plate materials with a certain size (the size of the humidity control plate material: a column with a diameter of 20 mm and a thickness of 4 mm and 2 mm, respectively); wherein the humidity control plate material is obtained by pressing at room temperature using a manual hydraulic tablet press (the mold used in the experiment is a cylinder with a diameter of 20 mm), and the first humidity control plate material is pressed using a pressure of 12 MPa, with a thickness of 2 mm and a density of 1361 kg / m 3 ; and the second humidity control plate material is pressed using a pressure of 6 MPa, with a thickness of 4 mm and a density of 1361 kg / m 3 ;

[0069] d. Using construction adhesive (ergo 7821, purchased from Kisling Company in Switzerland, coating thickness is 0.1mm) and aluminum foil (polar bear AL-610, size 60mm x 0.1mm, purchased from Shanghai Polar Bear Stationery Adhesive Co., Ltd.) (the construction adhesive is coated on the aluminum foil, and the aluminum foil covers the bottom and side of the temperature and humidity control board column, so that only the top of the temperature and humidity control material is in contact with the surrounding environment), the phase change board and two humidity control boards (the phase change board is placed between the two humidity control boards, that is, the first humidity control board, the humidity control board and the second humidity control board are sequentially stacked into a cylinder (the bottom of the cylinder is connected)) are pressed into a sandwich structure of temperature and humidity control board. Figure 1

[0070] Example 2

[0071] A temperature and humidity control material and its preparation process, the specific steps are as follows:

[0072] a. Put deionized water, hydrated salt phase change material (dodecahydrate sodium phosphate dibasic and trihydrate sodium phosphate dibasic; the ratio of the two is 97wt%:3wt%), nucleating agent sodium silicate nonahydrate in a glass bottle, then put the glass bottle in a 50℃ water bath pot and stir, stirring time is 20min, get mixed solution; then add porous material (micropowder silica gel) directly to the above mixed solution, then intermittent stirring at 50℃, stirring time is 80min, get composite phase change material; wherein the composite phase change material includes the following raw materials by weight percentage: hydrated salt phase change material 65%, deionized water 10%, nucleating agent 5%, porous material 20%;

[0073] b. Cool the prepared composite phase change material to room temperature, then use the mold to press the composite phase change material into a phase change board with a certain size (the size of the phase change board: cylinder with a diameter of 20mm, thickness of 4mm), the specific pressing method is the same as example 1;

[0074] c. Select inorganic mineral material (bentonite) with good moisture absorption performance as humidity control material, use the mold to make two humidity control boards with a certain size (the size of the humidity control board: cylinder with a diameter of 20mm, thickness of 4mm and 2mm respectively), the specific pressing method is the same as example 1;

[0075] d. Using construction adhesive (ergo 7821, purchased from Kisling Company in Switzerland, coating thickness is 0.1mm) and aluminum foil (polar bear AL-610, size 60mm x 0.1mm, purchased from Shanghai Polar Bear Stationery Adhesive Co., Ltd.) (aluminum foil covers the bottom and side of the temperature and humidity control board column), the phase change board and two humidity control boards are pressed into a sandwich structure of temperature and humidity control board.​

[0076] Effect Examples

[0077] The temperature and humidity control board was prepared according to the method of Example 1 (In order to more accurately evaluate the influence of the moisture absorption and release of the humidity control material on the performance of the phase change material, the diatomite needs to be saturated with moisture before being combined with the composite phase change material to form the temperature and humidity control board. The other steps are the same as those of Example 1). Then the prepared temperature and humidity control board was placed in a humidity environment with a relative humidity (RH) of 75% and 97% (room temperature) for 1 day, 2 days and 3 days respectively. In order to compare the thermal performance of the single composite phase change material exposed to the humidity environment and the thermal performance of the composite phase change material with the humidity control material, the single composite phase change board (relative humidity: 75%) was used as a control (the composite phase change material was prepared according to the method of Reference Example 1, and the density of the board was 815 kg / m 3 (pressure value not more than 2 MPa, thickness of the phase change board 4 mm), and finally the bottom and side surfaces of the column were wrapped with aluminum foil. The thermal performance (phase change temperature, enthalpy) of the material was determined by differential scanning calorimetry (DSC, NETZSCH 214 Polyma, Germany). The experiment was set in triplicate.

[0078] The results are shown in Figure 2 and Table 1: It can be seen that the humidity control material in the temperature and humidity control board prepared by the present application has an improvement effect on the thermal performance of the composite phase change material. The heat storage performance changes little under high humidity, and it is suitable for use in a greenhouse with high air relative humidity, and can realize the effect of simultaneously controlling the temperature and humidity fluctuations in the greenhouse. Under 75% humidity, the phase change enthalpy of the composite phase change board gradually decreases with the increase of the number of days, which is related to the easy water loss of sodium phosphate dibasic dodecahydrate in the natural state. Under 75% humidity, the phase change enthalpy of the temperature and humidity control board also gradually decreases with the increase of the number of days, but the phase change enthalpy is higher than that of the single composite phase change board. This is because the moisture-saturated humidity control material inhibits the water loss of sodium phosphate dibasic dodecahydrate. Under 97% humidity, the phase change enthalpy of the temperature and humidity control board also gradually decreases with the increase of the number of days, but the phase change enthalpy is higher than that under 75% humidity.

[0079] Table 1 Thermal performance of the material

[0080]

[0081] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods and shall be included in the protection scope of the present application.

Claims

1. A method for producing a temperature and humidity control material, characterized by, The method comprises the following steps: (1) mixing inorganic hydrated salt phase change material, nucleating agent and water uniformly, stirring at 40-55℃ for 10-20 min, then adding porous material, continuing to stir at 40-55℃ for 60-120 min to obtain composite phase change material; wherein the composite phase change material comprises the following raw materials in percentage by weight: inorganic hydrated salt phase change material 62-70%, deionized water 0-10%, nucleating agent 2-5%, porous material 20-30%; (2) cooling the composite phase change material obtained in step (1) to room temperature, then pressing it into phase change plate material; (3) pressing inorganic mineral material as humidity adjusting material into first humidity adjusting plate material and second humidity adjusting plate material; (4) sequentially layering and combining the first humidity adjusting plate material, phase change plate material and second humidity adjusting plate material to form sandwich structure, and coating the bottom surface and side surface thereof with building structural adhesive and aluminum foil to obtain heat and humidity adjusting plate material, i.e. the temperature and humidity adjusting material; the inorganic hydrated salt phase change material in step (1) is dodecahydrate sodium hydrogen phosphate, or inorganic hydrated salt phase change material obtained by mixing dodecahydrate sodium hydrogen phosphate and trihydrate diphosphoric acid potassium in the ratio of 97wt%:3wt%; the nucleating agent in step (1) is at least one of sodium silicate nonahydrate and strontium chloride hexahydrate; the porous material in step (1) is micro-powder silica gel; the inorganic mineral material in step (3) is at least one of diatomite and bentonite.

2. The method according to claim 1, wherein: the stirring temperature in step (1) is 48-50℃; the stirring time in step (1) is 15-20 min; the continuing stirring time in step (1) is 60-90 min.

3. The method according to claim 1, wherein: The phase change panel described in step (2) has a density of 750 to 900 kg / m 3 ; The first and second humidity control boards described in step (3) each have a density of 1200 to 1400 kg / m 3 .

4. The method according to claim 1, wherein: the size of the phase change plate material in step (2) is: length 450-600 mm, width 350-600 mm, thickness 8-15 mm; the size of the first and second humidity adjusting plate materials in step (3) is: length 450-600 mm, width 350-600 mm, thickness 2-15 mm.

5. The method according to claim 1, wherein: the pressure value of the pressing in step (2) is not more than 2 MPa; the pressure value of the pressing in step (3) is 6-12 MPa; the coating thickness of the building structural adhesive in step (4) is 0.1 mm.

6. A temperature and humidity control material, characterized by: obtained by the method according to any one of claims 1-5.

7. The temperature and humidity adjusting material according to claim 6 for use in greenhouse.

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