Compound fog-dissipating stream droplet agent with high infrared barrier function and application thereof in fog-dissipating stream droplet shed film

Abstract

This invention belongs to the field of greenhouse film production and application technology, and relates to a composite anti-fogging and anti-dripping agent with high infrared blocking function and its application in anti-fogging and anti-dripping greenhouse films. It comprises the following components by weight: 8-12 parts polycarbonate; 10-15 parts modified nano-titanium dioxide; 65-75 parts anti-fogging and anti-dripping agent stock solution; 1-5 parts dispersant; and 3-7 parts anti-aging agent. The polycarbonate is C4-C8 aliphatic polycarbonate, and the modified nano-titanium dioxide is anatase-type nano-titanium dioxide modified with a silane coupling agent. This invention utilizes the flexible alkyl chain (-C4H8-) of C4-C8 aliphatic polycarbonate to allow the carbonyl group (C=O) of modified nano-titanium dioxide to rotate freely, thereby bonding Ti4+ on the TiO2 surface. While retaining or even optimizing the core properties of nano-titanium dioxide such as ultraviolet shielding and photocatalysis, it significantly improves dispersion stability, avoids particle agglomeration, ensures the light transmittance of the entire membrane, and enhances the interfacial bonding force with the substrate, ensuring the stability of the coating.

Description

Technical Field

[0001] This invention belongs to the field of greenhouse film production and application technology, and particularly relates to a composite anti-fogging and anti-dripping agent with high infrared blocking function and its application in anti-fogging and anti-dripping greenhouse film. Background Technology

[0002] Anti-fogging and anti-drip agricultural greenhouse film is a functional film specially designed for agricultural greenhouses. Through special technology, it achieves the dual function of eliminating fog inside the greenhouse and guiding water droplets to flow down the film surface, thereby improving the crop growth environment and increasing yield and quality.

[0003] While existing anti-fogging and anti-drip agricultural greenhouse films achieve the dual functions of eliminating fog inside the greenhouse and guiding water droplets to flow down the film surface, they cannot effectively block infrared radiation (wavelength 7-14μm) at night, resulting in severe temperature loss in the greenhouse at night.

[0004] Currently, the main solution to this problem is to add infrared blocking agents (such as titanium dioxide) to the anti-fogging and anti-dripping agent. However, the use of infrared blocking agents has problems such as uneven dispersion, decreased light transmittance, and soaring costs. Moreover, the blocking rate is difficult to precisely control to the range of 70-90%. Summary of the Invention

[0005] This invention addresses the technical problems of the aforementioned anti-fogging and anti-dripping agricultural greenhouse film in blocking infrared radiation. It proposes a composite anti-fogging and anti-dripping agent with high infrared blocking function that is reasonably designed, has a simple formula, is low in cost, and can effectively block infrared radiation, as well as its application in the anti-fogging and anti-dripping greenhouse film.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a composite anti-fogging and anti-dripping agent with high infrared blocking function, comprising the following components in parts by weight:

[0007] 8 to 12 parts polycarbonate;

[0008] 10-15 parts of modified nano-titanium dioxide;

[0009] 65-75 parts of anti-fogging and anti-dripping agent stock solution;

[0010] 1 to 5 parts dispersant;

[0011] Anti-aging agent 3 to 7 parts;

[0012] The polycarbonate is a C4-C8 aliphatic polycarbonate, and the modified nano-titanium dioxide is anatase-type nano-titanium dioxide modified with a silane coupling agent.

[0013] Preferably, the silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0014] Preferably, the dispersant is polyvinylpyrrolidone.

[0015] Preferably, the anti-aging agent is a hindered amine anti-aging agent.

[0016] Preferably, the modified nano-titanium dioxide has a particle size range of 50-200 nm.

[0017] Preferably, the polycarbonate is prepared by melt transesterification polycondensation of 1,6-hexanediol and diphenyl carbonate.

[0018] This invention also provides a method for preparing a composite anti-fogging and anti-dripping agricultural greenhouse film with high infrared blocking function, comprising the following steps:

[0019] a. First, weigh the required raw materials according to the above-described composite anti-fogging and anti-dripping agent with high infrared blocking function;

[0020] b. Then, dissolve the polycarbonate in a mixed solvent of methyl ethyl ketone (MEK) and acetone to form a homogeneous colloid;

[0021] c. Add modified nano-titanium dioxide to the homogeneous colloid obtained in step b, and disperse it by ultrasonication to obtain a composite slurry;

[0022] d. The composite slurry is mixed at low speed with the anti-fogging and anti-dripping liquid, dispersant and anti-aging agent in a reactor to obtain a composite anti-fogging and anti-dripping agent with high infrared blocking function;

[0023] e. The composite anti-fogging and anti-dripping agent with high infrared blocking function obtained in step d is coated onto a PE base film using a micro-gravure roller and then cured in stages to obtain the desired composite anti-fogging and anti-dripping agricultural greenhouse film with high infrared blocking function, wherein the crystallinity of the polycarbonate in the coating layer is ≤15%.

[0024] Preferably, in step c, the ultrasonic dispersion frequency is 40 kHz and the dispersion time is 30 min.

[0025] Preferably, in step d, the reactor rotates at 300 rpm and the temperature is controlled at 40°C.

[0026] Preferably, step e is only required to ensure that the coating thickness of the composite anti-fogging and anti-dripping agent with high infrared blocking function is 8-12 μm.

[0027] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0028] 1. This invention provides a composite anti-fogging and anti-dripping agent with high infrared blocking function and its application in anti-fogging and anti-dripping greenhouse film. It utilizes the flexible alkyl chain (-C4H8-) of C4-C8 aliphatic polycarbonate to allow the carbonyl group (C=O) of modified nano-titanium dioxide to rotate freely, thereby bonding Ti4+ on the TiO2 surface. While retaining or even optimizing the core properties of nano-titanium dioxide such as ultraviolet shielding and photocatalysis, it significantly improves dispersion stability, avoids particle agglomeration, ensures the light transmittance of the entire greenhouse film, and enhances the interfacial bonding force with the substrate to ensure the stability of the coating.

[0029] 2. The combination ratio of C4-C8 aliphatic polycarbonate and modified nano-titanium dioxide carbonyl is linearly related to the infrared blocking rate (R²=0.98), thereby achieving directional control of the blocking rate of 70-90% and ensuring the quality of the greenhouse film.

[0030] 3. The composite anti-fogging and anti-dripping agent with high infrared blocking function provided by the present invention can be directly applied to existing coating production lines. Compared with the traditional preparation method of anti-fogging and anti-dripping agents, only a dispersion and mixing process is added, which makes it convenient to implement. Detailed Implementation

[0031] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0032] Numerous specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways than those described herein, and therefore the invention is not limited to the specific embodiments disclosed in the following specification.

[0033] Example 1 provides a composite anti-fogging and anti-dripping agent with high infrared blocking function.

[0034] First, weigh out the required amounts of aliphatic polycarbonate (8 parts by weight), modified nano-titanium dioxide (10 parts by weight), anti-fogging and anti-dripping agent stock solution (65 parts by weight), dispersant (1 part by weight), and anti-aging agent (3 parts by weight). Among these materials, the aliphatic polycarbonate is C4 aliphatic polycarbonate (with butanediol as the core monomer). The modified nano-titanium dioxide is anatase nano-titanium dioxide modified with KH-570 (γ-methacryloyloxypropyltrimethoxysilane). The modified nano-titanium dioxide exhibits good dispersion, excellent compatibility, and superior infrared blocking ability. The anti-fogging and anti-dripping agent stock solution is a commonly used anti-fogging and anti-dripping agent in existing greenhouse film production, namely an organosilicon / polyether copolymer. The dispersant used is polyvinylpyrrolidone (PVP), a water-soluble polymer formed by free radical polymerization of N-vinylpyrrolidone monomer, belonging to non-ionic polymer materials. Its molecular structure contains a pyrrolidone ring (with a polar amide group) and a nonpolar methylene chain. This "polar-nonpolar" coexistence structure effectively prevents titanium dioxide from agglomerating. Hindered amine anti-aging agents, such as Chimassorb 944, Tinuvin 622, and Tinuvin 123, all meet the requirements.

[0035] After weighing the required raw materials, polycarbonate is first dissolved in a methyl ethyl ketone (MEK) / acetone mixed solvent to form a homogeneous colloid. Then, modified nano-titanium dioxide is added to the homogeneous colloid and ultrasonically dispersed to obtain a composite slurry. This step is crucial; mixing the two first ensures stable dispersion of the modified nano-titanium dioxide. In this step, the flexible alkyl chains (-C4H8-) of the aliphatic polycarbonate allow the carbonyl groups (C=O) of the modified nano-titanium dioxide to rotate freely, thereby bonding to Ti4+ on the TiO2 surface. This significantly improves dispersion stability, prevents particle agglomeration, and ensures the overall light transmittance of the greenhouse film while retaining or even optimizing the core properties of titanium dioxide, such as UV shielding and photocatalysis. Furthermore, the ratio of aliphatic polycarbonate to modified nano-titanium dioxide shows a linear relationship with the infrared blocking rate (R²=0.98), ensuring directional control of the blocking rate to 70-90%.

[0036] Finally, the composite slurry is mixed at low speed with the anti-fogging and anti-dripping liquid, dispersant and anti-aging agent in a reactor to obtain a composite anti-fogging and anti-dripping agent with high infrared blocking function. This step can effectively utilize another property of modified nano titanium dioxide to enhance the interfacial bonding force between the obtained composite anti-fogging and anti-dripping agent and the substrate, and ensure the stability of the coating.

[0037] Example 2: This example provides a composite anti-fogging and anti-dripping agent with high infrared blocking function.

[0038] Compared with Example 1, the only difference in this example is the weight percentage of the relevant raw materials and the fact that the aliphatic polycarbonate is C6 aliphatic polycarbonate (hexanediol type), which is prepared by melt transesterification polycondensation reaction of 1,6-hexanediol and diphenyl carbonate.

[0039] The specific weight proportions are: 10 parts aliphatic polycarbonate, 12 parts modified nano titanium dioxide, 70 parts anti-fogging and anti-dripping agent mother liquor, 3 parts dispersant, and 5 parts anti-aging agent.

[0040] Example 3: This example provides a composite anti-fogging and anti-dripping agent with high infrared blocking function.

[0041] Compared with Example 1, the only difference in this example is the weight percentage of the relevant raw materials and the fact that the aliphatic polycarbonate is C8 aliphatic polycarbonate. Specifically, the weight percentages are 12 parts aliphatic polycarbonate, 15 parts modified nano titanium dioxide, 75 parts anti-fogging and anti-dripping agent mother liquor, 5 parts dispersant, and 7 parts anti-aging agent.

[0042] Testing and inspection:

[0043] The composite anti-fogging and anti-dripping agent with high infrared blocking function prepared in the above three embodiments is coated onto a PE base film using a micro-gravure roller and then cured in stages to obtain the desired composite anti-fogging and anti-dripping agricultural greenhouse film with high infrared blocking function. The crystallinity of polycarbonate in the coating layer is ≤15%. A crystallinity of ≤15% for polycarbonate in the coating layer ensures the carbonyl rotational freedom.

[0044] This experiment mainly tested four aspects: infrared blocking rate, visible light transmittance, droplet persistence, and haze.

[0045] 1. Infrared blocking rate

[0046] 1.1 Test Standard: Reference Standard: Infrared transmittance test method in GB / T 31034-2014 "Insulating Backsheet for Crystalline Silicon Solar Cell Modules" (applicable to similar functional film materials).

[0047] ASTM E424-71 (General Method for Infrared Transmittance Testing).

[0048] Definition: Infrared blocking rate usually refers to the blocking rate in a specific infrared band (such as 7~14 μm, corresponding to the main thermal radiation band). The calculation formula is: Infrared blocking rate = (1-transmittance) ×100%.

[0049] 1.2. Test Equipment and Methods:

[0050] Equipment: Fourier transform infrared spectrometer (FTIR, such as Nicolet iS50), equipped with an integrating sphere accessory (to reduce scattering errors).

[0051] 1.3. Steps:

[0052] Scan the background spectrum (baseline) without a sample.

[0053] Place the greenhouse film sample and test its transmission spectrum in the target wavelength band.

[0054] Calculate the average transmittance of a specific band (e.g., 7~14 μm) and then convert it to the blocking rate.

[0055] Key parameters: The test wavelength range and resolution (usually 4 cm) must be specified. -1 ), number of scans (average of 32 or more scans).

[0056] 1.4 Test Results:

[0057]

[0058] 2. Visible light transmittance

[0059] 2.1. Test standard: National standard: GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics".

[0060] ISO 134681 "Determination of total light transmittance of transparent plastic materials".

[0061] Definition: Average transmittance in the visible light band (380~780 nm), weighted by the human visual function (must conform to CIE standard light source D65).

[0062] 2.2. Test Equipment and Methods:

[0063] Equipment: UV-Vis spectrophotometer (such as PerkinElmer Lambda 950), equipped with a transmission sample chamber.

[0064] 2.3. Steps:

[0065] After calibrating the instrument, the transmission spectrum of the sample in the range of 380–780 nm was measured.

[0066] The average transmittance is calculated using the CIE standard weighted average.

[0067] Notice:

[0068] The incident angle of the light source needs to be controlled (usually perpendicular).

[0069] If the sample has color, additional color difference testing is required (e.g., ASTM D2244).

[0070] 2.4 Experimental Results:

[0071]

[0072] 3. Dripping persistence

[0073] 3.1. Testing Standards: Agricultural Industry Standards:

[0074] NY / T 1226-2006 Test method for anti-fogging properties of agricultural plastic films.

[0075] ASTM E96 "Test for moisture resistance of materials" (accelerated aging conditions can be referenced).

[0076] Definition: The duration for which a continuous water film (anti-drip performance) can form after water droplets condense on the surface of a thin film.

[0077] 3.2. Test Equipment and Methods:

[0078] Lab accelerated testing:

[0079] Constant temperature and humidity chamber: simulates a greenhouse environment (such as temperature 40℃ and humidity 90%), and regularly observes the morphology of water droplets on the surface.

[0080] Contact angle measuring instrument: tests the contact angle of water droplets (initial value <15° is acceptable; the angle increases after aging, indicating failure).

[0081] Field verification: The actual greenhouse film was laid, and the time when the drip-proof function failed was recorded (the geographical location, season and other environmental factors must be noted).

[0082] 3.3 Test Results:

[0083]

[0084] 4. Haze

[0085] 4.1. Testing Standard: National Standard:

[0086] GB / T 2410-2008 (Same as transmittance standard, including haze test method).

[0087] ASTM D1003 Standard Test Method for Haze and Transmittance of Transparent Plastics.

[0088] Definition: The percentage of luminous flux that deviates from the incident direction by more than 2.5° due to scattering.

[0089] 4.2. Test Equipment:

[0090] Equipment: Haze meter (such as BYK Gardner HazeGard Plus) or spectrophotometer with integrating sphere.

[0091] 4.3 Steps:

[0092] Measure the total transmitted light flux (T2) and the scattered light flux (T1).

[0093] Calculate the fog level: Fog level = T1 / T2 × 100%.

[0094] Note: Sample surface cleanliness and thickness uniformity can affect the results; multiple measurements are required to take an average.

[0095] 4.4 Test Results:

[0096]

[0097] Other comparisons:

[0098] A comparative experiment was conducted using aliphatic polycarbonate, aromatic polycarbonate, and aliphatic-aromatic copolymer polycarbonate.

[0099] Key Comparative Experimental Design

[0100] (a) The experimental group was prepared using the formulation provided in Example 2, except that the aliphatic polycarbonate was replaced, and the coating thickness was 10 μm.

[0101]

[0102] (II) Test conditions:

[0103] 1. Infrared blocking rate: ASTM E424 (8-14μm band)

[0104] 2. Bonding stability: After accelerated aging at 85℃ / 85%RH for 500 hours, the Ti-O=C bond strength attenuation rate was detected by XPS.

[0105] (III) Cause Analysis:

[0106] The flexible alkyl chain (-C4H8-) of aliphatic polycarbonate allows the carbonyl group (C=O) to rotate freely, resulting in better bonding to the TiO2 surface. 4+ This allows titanium dioxide to be dispersed more stably, while the rigid benzene ring of aromatic polycarbonate hinders carbonyl orientation, allowing only a small number of carbonyl groups to contact Ti. 4+ (Bond length > 2.3 Å) results in an incomplete infrared reflective network. Furthermore, the aliphatic and aromatic segments of the aliphatic-aromatic copolymer polycarbonate are microphase-separated, leading to TiO2 enrichment in the aliphatic region and uneven dispersion, thus resulting in the lowest infrared blocking efficiency. Another reason is that other polycarbonates contain benzene rings, which form a rigid barrier, weakening the infrared blocking efficiency through electronic effects. 4+ The coordination activity of carbonyl groups leads to the continued aggregation of nano-titanium dioxide, affecting infrared blocking rate and light transmittance.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A composite anti-fogging and anti-dripping agent with high infrared blocking function, characterized in that, The ingredients are included in parts by weight as follows: 8 to 12 parts polycarbonate; 10-15 parts of modified nano-titanium dioxide; 65-75 parts of anti-fogging and anti-dripping agent stock solution; 1 to 5 parts dispersant; Anti-aging agent 3 to 7 parts; Wherein, the polycarbonate is C4-C8 aliphatic polycarbonate, the modified nano titanium dioxide is anatase nano titanium dioxide modified with silane coupling agent, and the anti-fogging and anti-dripping agent mother liquor is organosilicon / polyether copolymer; The preparation method of a composite anti-fogging and anti-dripping agent with high infrared blocking function includes the following steps: a. First, weigh the required raw materials according to the composite anti-fogging and anti-dripping agent with high infrared blocking function as described above; b. Then, dissolve the polycarbonate in a mixed solvent of methyl ethyl ketone (MEK) and acetone to form a homogeneous colloid; c. Add modified nano-titanium dioxide to the homogeneous colloid obtained in step b, and disperse it by ultrasonication to obtain a composite slurry; d. The composite slurry is mixed at low speed with the anti-fogging and anti-dripping agent mother liquor, dispersant and anti-aging agent in a reactor to obtain a composite anti-fogging and anti-dripping agent with high infrared blocking function.

2. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 1, characterized in that, The silane coupling agent is γ-methacryloxypropyltrimethoxysilane.

3. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 2, characterized in that, The dispersant is polyvinylpyrrolidone.

4. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 3, characterized in that, The anti-aging agent is a hindered amine anti-aging agent.

5. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 4, characterized in that, The modified nano-titanium dioxide has a particle size range of 50-200 nm.

6. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 5, characterized in that, The polycarbonate is prepared by melt transesterification polycondensation reaction of 1,6-hexanediol and diphenyl carbonate.

7. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 6, characterized in that, In step c, the ultrasonic dispersion frequency is 40 kHz and the dispersion time is 30 min.

8. The composite anti-fogging and anti-dripping agent with high infrared blocking function according to claim 7, characterized in that, In step d, the reactor rotates at 300 rpm and the temperature is controlled at 40°C.

9. A method for preparing a composite anti-fogging and anti-drip agricultural greenhouse film with high infrared blocking function, characterized in that, The composite anti-fogging and anti-dripping agent with high infrared blocking function obtained in claim 8 is coated onto a PE base film using a micro-gravure roller and then cured in stages to obtain the desired composite anti-fogging and anti-dripping agricultural greenhouse film with high infrared blocking function, wherein the crystallinity of the polycarbonate in the coating layer is ≤15%.

10. The method for preparing the composite anti-fogging and anti-dripping agricultural greenhouse film with high infrared blocking function according to claim 9, characterized in that, The coating thickness of the composite anti-fogging and anti-dripping agent with high infrared blocking function is 8-12μm.

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