Preparation process of photo-oxygen synergistic triggered HFO self-curing self-sealing adhesive

Abstract

The application provides a preparation process of a light-oxygen synergistically triggered HFO self-curing self-sealing adhesive. The process comprises the following steps: first, preparing polyvinylidene fluoride coated sodium chlorite microcapsules; then, mixing the microcapsules with a light-oxygen initiator BP-4, a crosslinking agent and a polyether polyol to prepare a composite additive; finally, adding the composite additive into an HFO body and mixing uniformly at high speed to obtain the self-sealing adhesive. The application encapsulates the oxidizing agent by using the microcapsules, combines with the BP-4 light initiator, and triggers the HFO double bond free radical polymerization by the synergistic action of the ambient light and oxygen when the leakage occurs, so that the thixotropic gel is rapidly formed within 5-8 seconds, and the leakage reduction rate is more than 95%. The self-sealing adhesive has good mutual solubility with the HFO body, the refrigeration efficiency reduction rate is only 1.0-1.8%, and the homogeneous phase is stable when the self-sealing adhesive is stored in the dark at room temperature for 60 days. The application solves the problems of the single triggering of the existing leak stopper, the easy failure, the response lag and the poor compatibility with the HFO working medium, and is suitable for the intelligent leakage plugging of the refrigeration and thermal management system.

Description

Technical Field

[0001] This invention relates to the field of refrigerant additive technology, specifically to a preparation process for a photo-oxidation synergistic triggered HFO self-condensing and self-sealing adhesive. Background Technology

[0002] With increasingly stringent global regulations on greenhouse gases, low-GWP (Global Warming Potential) HFO refrigerants have become key alternatives to traditional Freon refrigerants, widely used in residential refrigeration, industrial cold chain, and new energy thermal management systems. However, the long-standing industry pain point of refrigerant leakage has not disappeared with the iteration of refrigerants. Leaks not only lead to a sharp drop in system energy efficiency and equipment damage, but also increase maintenance costs and environmental burden due to refrigerant replenishment. Therefore, developing intelligent refrigerants with self-sealing capabilities in case of leakage has become an urgent industry need.

[0003] To address leakage issues, various leak-sealing solutions have been developed in the prior art. For example, CN109796934A discloses a leak-sealing agent for refrigeration systems that achieves physical sealing through components such as rigid polybutylene and epoxy resin. However, this solution is a remedial sealing method after a leak is manually discovered; the leak-sealing agent itself lacks the intelligent triggering capability to autonomously sense and respond to leaks, and cannot achieve in-situ self-solidification.

[0004] Publication number CN101260287A proposes a vehicle air conditioning leak sealant composed of alkyl silicone oil, organic amine curing agent, etc., which can solidify at the leak point to form a repair layer. However, this solution has a significant drawback: its sealant components are only physically mixed with the refrigerant, resulting in poor compatibility, and actual tests have shown that this leads to a significant decrease in cooling efficiency.

[0005] Further analysis of existing technologies reveals that self-sealing solutions based on pressure, oxygen, or light triggering are all limited by the inherent bottleneck of a single trigger signal: plugging agents relying solely on pressure or oxygen changes exhibit a delayed response in the event of minute leaks or inert environments, typically requiring more than 30 seconds; while materials relying solely on light triggering will completely fail if the leak point is located in a dark corner of the pipeline or is obscured by insulation, leading to sealing failure. Furthermore, most existing solutions require modifications to the equipment and pipeline structure for pre-installation, or the added nanomaterials and solid particles are prone to sedimentation and stratification in the working fluid, affecting long-term stability and making it difficult to meet the distillation and recovery requirements of HFO systems.

[0006] In summary, the core deficiency of existing technologies lies in the lack of an intelligent triggering mechanism that is highly miscible with the HFO substrate, does not sacrifice cooling performance, and provides rapid, reliable, and dual-signal protection. How to reliably activate the sealing reaction within seconds of a leak occurring, regardless of ambient light intensity or concealed location, is a key challenge hindering technological breakthroughs in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a preparation process for a photo-oxidation synergistic triggering type HFO self-condensing and self-sealing adhesive, thereby solving the technical problem that "existing sealing agents are prone to failure due to a single triggering mechanism, have a slow response speed, and have poor compatibility with HFO working fluid, resulting in a significant decrease in refrigeration efficiency".

[0008] To achieve the above objectives, the present invention is implemented using the following technical solution: This invention provides a preparation process for a photo-oxidation synergistic triggered HFO self-curing and self-sealing adhesive, comprising the following preparation steps: (1) Polyvinylidene fluoride is dissolved in DMF to form an oil phase; dimethyl silicone oil, emulsifier and sodium chlorite aqueous solution are mixed and emulsified by high-speed shearing to form an emulsion; the oil phase is added to the emulsion, DMF is heated to volatilize and polyvinylidene fluoride is deposited, and microcapsules are obtained after washing and drying. (2) The photo-oxidation initiator, the microcapsules obtained in step (1), the crosslinking agent and the polyether polyol are mixed in proportion to obtain a composite additive; (3) Add the HFO body to the high-speed shearing and mixing equipment, add the composite additive prepared in step (2), stir and mix evenly to form HFO self-curing and self-sealing adhesive.

[0009] Specifically, the composite additive is 1-3% of the bulk HFO.

[0010] Specifically, the emulsifier is at least one of propylene glycol monostearate, soybean lecithin, and glyceryl monostearate.

[0011] Specifically, the photo-oxidation initiator is benzophenone derivative BP-4.

[0012] Specifically, the crosslinking agent is selected from at least one of KH-550, KH-540, and KH-792.

[0013] Specifically, the composite additive, by mass parts, includes: 1 to 1.8 parts of photo-oxidation initiator, 0.5 to 1 part of microcapsules, and 0.2 to 0.6 parts of polyether polyol.

[0014] Specifically, the HFO body is at least one of R1234yf and R1234ze(E).

[0015] Specifically, the microcapsules have a particle size of 1–5 μm and a wall thickness of 0.2–0.5 μm.

[0016] Specifically, the high-speed shear stirring speed is 3000-5000 rpm, the stirring time is 20-30 minutes, and the stirring temperature is 25-30℃.

[0017] This invention provides a process for preparing a photo-oxidation synergistically triggered HFO self-curing and self-sealing adhesive.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) The present invention adopts a photo-oxygen synergistic triggering mechanism, which does not rely on pressure drop triggering. In the case of no significant change in system pressure (such as micro-leakage, slow leakage of pressure holding system) and only ambient light and air, gel can still be formed within 5 to 8 seconds, which improves the triggering reliability and achieves a leakage reduction rate of 95.3 to 96.2% in 15 seconds. It effectively solves the problem of leakage plugging failure in dark corners or environments with no significant pressure change.

[0019] (2) This invention encapsulates sodium chlorite oxidant in polyvinylidene fluoride wall material using microencapsulation technology, which effectively prevents the oxidant from reacting prematurely with components such as photoinitiators and polyether polyols. After 60 days of storage at room temperature away from light, the system remains homogeneous and stable, without stratification, precipitation or discoloration. At the same time, it ensures that the oxidant is released rapidly when leakage is triggered, which significantly improves the reliability of the product.

[0020] (3) The sealing layer formed after 30 minutes of sealing in this invention has a Shore hardness of 35-45A and a pressure resistance of 0.52-0.62MPa. It has both good elasticity and mechanical strength, achieving both high efficiency self-sealing and low loss of refrigeration performance. The composite additive only needs to be mixed with the HFO body at high speed without modifying the existing refrigeration system pipeline structure. The self-curing and self-sealing adhesive can be directly applied to HFO working fluid systems in the fields of household refrigeration, industrial cold chain, and new energy thermal management, and has good prospects for industrial promotion. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the leakage self-sealing working principle of the photo-oxidation synergistic triggering type HFO self-curing and self-sealing adhesive of the present invention.

[0022] Figure 2 This is a flowchart illustrating the preparation process of the microcapsules of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the component structure and mechanism of action of the HFO self-curing and self-sealing adhesive of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention addresses the problems of existing leak-sealing agents that rely on a single trigger signal (pressure, oxygen, or light alone), resulting in delayed response, easy failure in the absence of light or low light environments, and in leak scenarios with minor leaks and minimal pressure drop in pressure-holding systems. It also addresses the issues of poor compatibility between added solid particles and the HFO working fluid, affecting refrigeration efficiency. The invention proposes a technical solution for preparing a photo-oxygen synergistic trigger-type HFO self-condensing and self-sealing adhesive. Its core mechanism involves encapsulating sodium chlorite oxidant in polyvinylidene fluoride microcapsules, which are then co-dispersed with the benzophenone derivative BP-4 photoinitiator within the HFO bulk. Under normal operating conditions, the system operates in a high-pressure, low-oxygen, and light-protected environment. The microcapsules remain stable, the photoinitiator is in an inert state, and the system exhibits good miscibility with HFO, having minimal impact on refrigeration performance. In the event of a leak, oxygen from the air and ambient light simultaneously enter the leak point: on one hand, oxygen causes the microcapsule wall material to rupture and release sodium chlorite, generating reactive oxygen species; on the other hand, BP-4 absorbs light energy and generates free radicals. The synergistic effect of light and oxygen rapidly initiates free radical polymerization of the double bonds in HFO molecules with the cross-linking agent. Simultaneously, the polyether polyol participates in the formation of a three-dimensional cross-linked network, transforming into a thixotropic gel within seconds, achieving immediate sealing. This invention ensures storage stability through microencapsulation and guarantees reliable triggering in dark corners and shaded environments through dual light and oxygen signals, thus solving the problems of slow response, easy failure, and poor compatibility in existing technologies. The preparation process and effects of this invention are further illustrated below with specific embodiments.

[0026] (1) Dissolve polyvinylidene fluoride with a fluorine content of 55-65% in DMF to form an oil phase; add 1-5 parts of propylene glycol monostearate and 10-30 parts of sodium chlorite aqueous solution with a mass concentration of 5-20% based on 100 parts of dimethyl silicone oil. After mixing, emulsify at a high speed of 10000-15000 r / min to form an emulsion. Add the oil phase to the emulsion. The volume ratio of the oil phase to the emulsion is 1:(2-5). Then send the mixed emulsion to a separation tower and heat it to 60-70℃ at 5℃ / min to volatilize DMF and cause polyvinylidene fluoride to deposit. Then the material enters the product concentration tank through a cooler, is washed with deionized water, and vacuum dried at 40-60℃ to obtain microcapsules. (2) By mass fraction, 1-1.8 parts of benzophenone derivative BP-4, 0.5-1 parts of microcapsules, and 0.2-0.6 parts of polyether polyol PEG-400 are mixed for 10-20 minutes to obtain a composite additive for later use. (3) At 25~30℃, add HFO body to turbine high-speed shear mixing equipment, add 1~3% of composite additives by mass of HFO body, and stir at 3000~5000r / min for 20~30 minutes to obtain HFO self-curing self-sealing adhesive.

[0027] In this invention, the particle size of the prepared microcapsules is controlled at 1-5 μm and the wall thickness is 0.2-0.5 μm. This size range is beneficial for the stable dispersion of microcapsules in HFO without affecting the refrigerant flowability and heat exchange performance. At the same time, it can respond quickly to ambient oxygen when leakage occurs, realizing the rapid release of oxidant and photo-oxidation synergistic triggering polymerization.

[0028] Example 1; (1) Polyvinylidene fluoride with a fluorine content of 55% was dissolved in DMF to form an oil phase; based on 100 parts of dimethyl silicone oil, 1 part of propylene glycol monostearate and 10 parts of sodium chlorite aqueous solution with a mass concentration of 5% were added. After mixing, the mixture was emulsified by high-speed shearing at 10000r / min to form an emulsion. The oil phase was added to the emulsion, and the volume ratio of the oil phase to the emulsion was 1:2. The mixed emulsion was then sent to a separation tower and heated to 60°C at 5°C / min to volatilize DMF and cause polyvinylidene fluoride to deposit. The material was then cooled and entered the product concentration tank, washed with deionized water, and vacuum dried at 40°C to obtain microcapsules. (2) By mass, 1 part of benzophenone derivative BP-4, 0.5 parts of microcapsules, and 0.2 parts of polyether polyol PEG-400 are mixed for 10 min to obtain a composite additive for later use. (3) At 25°C, R1234yf was added to a turbine-type high-speed shearing mixer, and 1% of the HFO bulk mass of composite additives were added. The mixture was stirred at 3000 r / min for 20 minutes to obtain HFO self-curing self-sealing adhesive.

[0029] Example 2; (1) Dissolve polyvinylidene fluoride with a fluorine content of 60% in DMF to form an oil phase; add 1 part of propylene glycol monostearate and 20 parts of sodium chlorite aqueous solution with a mass concentration of 100 parts based on the volume of dimethyl silicone oil. After mixing, emulsify at a high speed of 12000r / min to form an emulsion. Add the oil phase to the emulsion. The volume ratio of the oil phase to the emulsion is 1:3. Then send the mixed emulsion to the separation tower and heat it to 65℃ at 5℃ / min to volatilize DMF and cause polyvinylidene fluoride to deposit. Then the material enters the product concentration tank through the cooler, and is washed with deionized water and vacuum dried at 50℃ to obtain microcapsules. (2) By mass, 1.3 parts of benzophenone derivative BP-4, 0.8 parts of microcapsules, and 0.3 parts of polyether polyol PEG-400 are mixed for 15 min to obtain a composite additive for later use. (3) At 28℃, R1234yf was added to a turbine-type high-speed shearing mixer, and 2% of the HFO bulk mass of composite additives were added. The mixture was stirred at 4000r / min for 25 minutes to obtain HFO self-curing self-sealing adhesive.

[0030] Example 3; (1) Dissolve polyvinylidene fluoride with a fluorine content of 65% in DMF to form an oil phase; add 5 parts of propylene glycol monostearate and 30 parts of sodium chlorite aqueous solution with a mass concentration of 20% based on 100 parts of dimethyl silicone oil. After mixing, emulsify at a high speed of 15000r / min to form an emulsion. Add the oil phase to the emulsion. The volume ratio of oil phase to emulsion is 1:5. Then send the mixed emulsion to the separation tower and heat it to 70℃ at 5℃ / min to volatilize DMF and cause polyvinylidene fluoride to deposit. Then the material enters the product concentration tank through the cooler, and is washed with deionized water and vacuum dried at 60℃ to obtain microcapsules. (2) By mass, 1.8 parts of benzophenone derivative BP-4, 1 part of microcapsules, and 0.6 parts of polyether polyol PEG-400 were mixed for 20 min to obtain a composite additive. (3) At 30℃, R1234yf was added to a turbine high-speed shearing mixer, and 3% of the HFO bulk mass of composite additives were added. The mixture was stirred at 3000r / min for 20 minutes to obtain HFO self-curing self-sealing adhesive.

[0031] Example 4; (1) Dissolve polyvinylidene fluoride with a fluorine content of 60% in DMF to form an oil phase; add 1 part of propylene glycol monostearate and 20 parts of sodium chlorite aqueous solution with a mass concentration of 100 parts based on the volume of dimethyl silicone oil. After mixing, emulsify at a high speed of 12000r / min to form an emulsion. Add the oil phase to the emulsion. The volume ratio of the oil phase to the emulsion is 1:3. Then send the mixed emulsion to the separation tower and heat it to 65℃ at 5℃ / min to volatilize DMF and cause polyvinylidene fluoride to deposit. Then the material enters the product concentration tank through the cooler, and is washed with deionized water and vacuum dried at 50℃ to obtain microcapsules. (2) By mass, 1.3 parts of benzophenone derivative BP-4, 0.8 parts of microcapsules, and 0.3 parts of polyether polyol PEG-400 are mixed for 15 min to obtain a composite additive for later use. (3) At 28℃, R1234ze(E) was added to a turbine high-speed shear mixing device, and 2% of the HFO bulk mass of composite additives were added. The mixture was stirred at 4000r / min for 25 minutes to obtain HFO self-curing self-sealing adhesive.

[0032] Comparative Example 1; The difference between Comparative Example 1 and Example 2 is that step (1) is omitted, and step (2) is changed to: 1.3 parts of benzophenone derivative BP-4, 0.8 parts of sodium chlorite, and 0.3 parts of polyether polyol PEG-400 are mixed for 15 min by mass to obtain a composite additive for later use; the remaining steps are the same as in Example 2.

[0033] Comparative Example 2; The difference between Comparative Example 2 and Example 2 is the difference in step (2). Step (2) is changed to: 0.8 parts by mass of microcapsules and 0.3 parts by mass of polyether polyol PEG-400 are mixed for 15 min to obtain a composite additive for later use; the remaining steps are the same as in Example 2.

[0034] Comparative Example 3; The difference between Comparative Example 3 and Example 2 lies in the difference in step (1). Step (1) is changed to: dissolving polyvinylidene fluoride with a fluorine content of 60% in DMF to form an oil phase; adding 1 part of propylene glycol monostearate and 20 parts of water based on 100 parts of dimethyl silicone oil, mixing and emulsifying at a high speed of 12000 r / min to form an emulsion, adding the oil phase to the emulsion, with a volume ratio of oil phase to emulsion of 1:3, heating to 65°C at 5°C / min to volatilize DMF and deposit polyvinylidene fluoride, and then the material enters the product concentration tank through a cooler, and is washed with deionized water and vacuum dried at 50°C to obtain microcapsules; the remaining steps are the same as in Example 2.

[0035] Comparative Example 4; The difference between Comparative Example 4 and Example 2 is the difference in step (3). Step (3) is changed to: at 28°C, R1234yf is added to a turbine high-speed shear mixing device, and 5% of the HFO bulk mass of composite additive is added. The mixture is stirred at 4000r / min for 25 minutes to obtain HFO self-curing self-sealing adhesive; the remaining steps are the same as in Example 2.

[0036] Test and Results Analysis Gel time determination: Under normal temperature (25±2℃), normal pressure (0.1MPa), and natural light ≥500lx conditions, the test system was coated onto a 0.5mm pore size simulated leakage orifice, and the time required from the start of leakage to the formation of thixotropic gel was recorded.

[0037] Leakage plugging efficiency measurement: Referring to GB / T30579-2014 standard, at a 0.5mm diameter leak, the leakage amount before plugging and 15 seconds after plugging is measured, and the leakage reduction rate is calculated by the following formula: Leakage reduction rate (%) = (leakage amount before plugging - leakage amount 15 seconds after plugging) / leakage amount before plugging × 100%.

[0038] Shore hardness test of sealing layer: After 30 minutes of leak sealing, the Shore hardness of the cured sealing layer is measured in accordance with GB / T531.1-2008 (Type A hardness tester).

[0039] Refrigeration efficiency change measurement: Referring to GB / T21360-2008 standard, after adding the test system to the refrigeration equipment, the refrigeration efficiency after the equipment has been running stably is measured and compared with the pure HFO without additives, and the change rate is calculated.

[0040] Sealing layer pressure resistance test: After 30 minutes of leak sealing, gradually increase the pressure at the leak point and record the pressure value (MPa) when the sealing layer is broken down or significant leakage occurs.

[0041] Storage stability test: The test system is sealed in a transparent glass container and stored at room temperature in the dark for 60 days. Observe whether there is stratification, precipitation or color change.

[0042] The performance test results of each embodiment and comparative example are shown in Table 1.

[0043] Table 1

[0044] As shown in Table 1, Examples 1-4 all employed the photo-oxidation synergistic triggering system described in this invention. Under leakage conditions, all examples formed thixotropic gels within 5-8 seconds, achieving a leakage reduction rate of 95.3-96.2% after 15 seconds. After curing for 30 minutes, the Shore hardness was 35-45A, the pressure resistance was 0.52-0.62 MPa, and the cooling efficiency reduction rate was only 1.0-1.8%. The mixture remained homogeneous and stable after 30 days of storage. This indicates that the composite additive described in this invention has good miscibility with the HFO bulk, and can achieve rapid, reliable, and low-performance-loss self-condensation and self-sealing within a dosage range of 1-3%.

[0045] Comparative Example 1 directly added unmicroencapsulated sodium chlorite. Although the gelation time was shortened to 4.2 seconds, the refrigeration efficiency decreased by as much as 3.5%. After 60 days of storage, the sodium chlorite turned yellow and separated into layers. The pressure resistance was only 0.32 MPa. This indicates that without microencapsulation protection, sodium chlorite decomposed prematurely during storage or reacted with the system, resulting in poor stability and severely deteriorated refrigeration performance.

[0046] Comparative Example 2, without the addition of BP-4, had a gel time >60 seconds, a leakage reduction rate of <5% after 15 seconds, a hardness <5A, and a pressure resistance of <0.05MPa. It was almost impossible to form an effective sealing layer, indicating that without a photoinitiator, the sodium chlorite released from the microcapsules was difficult to be excited to generate chlorine free radicals, and the HFO double bonds could not undergo free radical polymerization, confirming that the light signal is a necessary condition for triggering crosslinking.

[0047] Comparative Example 3 prepared microcapsules without sodium chlorite. The gel time was as long as 35.6 seconds, the leakage reduction rate was only 61.2%, the hardness was 23A, and the pressure resistance was 0.23MPa. This shows that although there was BP-4 photoinitiation, the lack of oxidant meant that the polymerization efficiency was extremely low by relying solely on direct photoinitiation, and it was impossible to form an effective blockage within a second. This proves that oxygen signal is also an indispensable component of the triggering system.

[0048] Comparative Example 4 increased the total amount of composite additives to 5%, which slightly improved the gel time (5.8 seconds), leakage reduction rate (96.8%), and pressure resistance (0.68 MPa). However, the refrigeration efficiency reduction rate increased sharply to 3.9%, and slight thickening occurred after 30 days of storage. This indicates that although excessive composite additives can further improve the sealing speed and strength, they will affect the refrigeration performance and long-term storage stability.

[0049] Figure 1 This is a schematic diagram illustrating the leakage self-sealing working principle of the photo-oxidation synergistic triggering type HFO self-curing self-sealing adhesive of the present invention. In the diagram, label 1 represents the homogeneous self-curing system under normal operating conditions, label 2 represents the leak point, label 3 represents ambient light, label 4 represents air, label 5 represents the self-curing self-sealing adhesive, and label 6 represents the sealing layer formed after curing. Figure 1 As shown, the entire process of the refrigeration system is demonstrated, from the normal high-pressure, low-oxygen, and sealed operating condition, to the simultaneous entry of air and ambient light into the leak point after a leak occurs, forming a photo-oxygen dual-signal trigger condition, to the rapid formation of a thixotropic gel within 5-8 seconds to achieve immediate sealing, and finally to the curing of an elastic sealing layer with a Shore hardness of A35-A45 and a pressure resistance of up to 0.6MPa after 30 minutes. This intuitively demonstrates the core technical features of the present invention: photo-oxygen synergistic triggering, second-level response, and long-term sealing.

[0050] Figure 2 This is a flow chart of the microcapsule preparation process of the present invention, which fully illustrates the entire process from raw material pretreatment to finished product: the raw materials are pretreated to prepare an oil phase, and then emulsified by high-speed shearing to form a stable emulsion; the emulsion is heated and enters a separation tower, where the evaporated phase is fully volatilized and the unreacted system is recycled to achieve the deposition and coating of the wall material; subsequently, the material enters a product concentration tank through a cooler, and after washing and drying, the finished microcapsule is obtained; the waste liquid generated in the process is treated and discharged, realizing continuous and low-loss microcapsule preparation, and clearly demonstrating the process steps and recycling design of the present invention.

[0051] Figure 3 This is a schematic diagram illustrating the component structure and mechanism of action of the HFO self-curing and self-sealing adhesive of the present invention. Figure 3 In the diagram, label 1 represents a fluorine-containing linear polymer chain, label 2 represents a CN bond, label 3 represents a Si-O-PEG-O-Si bond, and label 4 represents a three-dimensional cross-linked network; for example... Figure 3 As shown, firstly, the amino group of KH-550 undergoes a Michael addition reaction with the HFO double bond, introducing a hydrolyzable silane group into the system; subsequently, the hydroxyl group of PEG-400 undergoes a condensation reaction with the silanol generated by the hydrolysis of KH-550 to form crosslinking point 3, ultimately constructing a sealing layer with a three-dimensional network structure as the main body. The hardness of this sealing layer is Shore A35-A45, which has both good elasticity and mechanical strength, and can achieve long-term sealing of leaks in the refrigeration system.

[0052] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A preparation process for a photo-oxidation synergistic triggered HFO self-curing and self-sealing adhesive, characterized in that, Includes the following steps: (1) Polyvinylidene fluoride is dissolved in DMF to form an oil phase; dimethyl silicone oil, emulsifier and sodium chlorite aqueous solution are mixed and emulsified by high-speed shearing to form an emulsion; the oil phase is added to the emulsion, DMF is heated to volatilize and polyvinylidene fluoride is deposited, and microcapsules are obtained after washing and drying. (2) The photo-oxidation initiator, the microcapsules obtained in step (1), the crosslinking agent and the polyether polyol are mixed in proportion to obtain a composite additive; (3) Add the HFO body to the high-speed shearing and mixing equipment, add the composite additive prepared in step (2), stir and mix evenly to form HFO self-curing and self-sealing adhesive; The composite additive is 1-3% of the mass of HFO.

2. The process according to claim 1, characterized in that, In step (1), the emulsifier is at least one of propylene glycol monostearate, soybean lecithin, and glyceryl monostearate.

3. The process according to claim 1, characterized in that, In step (2), the photo-oxidation initiator is benzophenone derivative BP-4.

4. The process according to claim 1, characterized in that, In step (2), the crosslinking agent is selected from at least one of KH-550, KH-540, and KH-792.

5. The process according to claim 1, characterized in that, The composite additive, by mass parts, includes: 1 to 1.8 parts of photo-oxidation initiator, 0.5 to 1 part of microcapsules, and 0.2 to 0.6 parts of polyether polyol.

6. The process according to claim 1, characterized in that, The HFO body is at least one of R1234yf and R1234ze(E).

7. The process according to claim 1, characterized in that, The microcapsules have a particle size of 1–5 μm and a wall thickness of 0.2–0.5 μm.

8. The process according to claim 1, characterized in that, The high-speed shear stirring speed is 3000-5000 rpm, the stirring time is 20-30 minutes, and the stirring temperature is 25-30℃.

9. An HFO self-curing and self-sealing adhesive prepared by the method according to any one of claims 1 to 8.

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