Dendritic cross-linked structure fluoride-free oil-proofing agent and preparation method thereof

Abstract

The preparation method comprises the following steps: carrying out copolymerization on a vinyl siloxane monomer, a hydrogen-containing siloxane monomer and an unsaturated double-bond organic monomer to obtain tree-shaped silicon resin, and mixing the tree-shaped silicon resin with a solvent to obtain the tree-shaped cross-linked structure fluorine-free oil-proof agent, the molecular weight of the vinyl siloxane monomer is 1000 to 3000; the molecular weight of the hydrogen-containing siloxane monomer is 1000 to 3000; the unsaturated double-bond organic monomer is any one or combination of a vinyl aromatic monomer or an olefin monomer. The dendritic structure silicon resin disclosed by the invention combines the advantages of a dendritic polymer and silicon resin through a unique molecular structure design, and has excellent comprehensive performance. And due to high heat resistance, the cable can be stably used in a high-temperature environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional materials, and particularly relates to a fluorine-free oil-proof agent with a tree-shaped cross-linked structure and a preparation method thereof. BACKGROUND

[0002] At present, intelligent devices have become indispensable tools in life, such as mobile phones, watches, earphones, intelligent sound boxes and other intelligent household electrical products. The acoustic and electrical components inside the above devices are very fragile and are easily invaded by water, oil and solid particles (dust, waste, dangerous fragments), resulting in damage to the devices. The main solution is to add a protective layer at the position of the external through hole, and the protective layer is usually made of gauze, steel mesh and film material to ensure air permeability, and at the same time, a barrier is formed at the position of the through hole to effectively isolate dirt and dust. However, the above materials have weak oil stain resistance, so it is necessary to perform oil-repellent modification treatment on them. In fact, so far, the developed super-oil-repellent coating all uses fluorinated compounds with a large number of CF 2- and CF 3- groups, such as PTFE, perfluorosilane and perfluoropolymer. Considering the limitation of the inherent surface tension of the material, basically, the previous high-oil-repellent coating is based on fluorinated materials with surface energy.

[0003] CN118930763A discloses a fluorine-free water-proof agent, and the preparation method thereof is an acrylate type, in which long-chain alkyl and epoxy active groups are added to facilitate the reaction with the surface active groups of the fabric to enhance the water washing resistance and provide better hand feeling. The formula mainly uses acrylate as the main body, and the surface tension is relatively high, and the water-proof is mainly considered, so the oil-proof level cannot be reached.

[0004] CN116854888A discloses a resin with a tree-shaped structure formed by cross-linking trimethylolpropane with IPDI and diethanolamine to achieve water-proof effect, but the polymer contains a large number of hydrophilic bonds such as formate ester bonds, ether bonds, hydroxyl groups and ionic bonds, and the surface tension is relatively high, the compatibility with the PTFE film is poor, the PTFE film surface is repelled, the hydrophilic bonds are arranged outward, the overall tension of the film surface is improved, and the water-proof and oil-proof properties are affected. SUMMARY

[0005] In view of this, the present application aims to provide a fluorine-free oil-proof agent with a tree-shaped cross-linked structure and a preparation method thereof to solve at least one technical problem in the background art.

[0006] To achieve the above-mentioned purposes, the technical scheme of the present application is as follows: A preparation method of a fluorine-free oil-proof agent with a tree-shaped cross-linked structure, comprising the following steps: copolymerizing a vinyl siloxane monomer, a hydrogen-containing siloxane monomer and an unsaturated double bond organic monomer to obtain a tree-shaped structure silicon resin, and mixing the tree-shaped structure silicon resin and a solvent to obtain the fluorine-free oil-proof agent with a tree-shaped cross-linked structure. The molecular weight of the vinyl siloxane monomer is 1000-3000; The molecular weight of the hydrogen-containing siloxane monomer is 1000-3000; The unsaturated double bond organic monomer is any one or a combination of a vinyl aromatic monomer or an olefin monomer.

[0007] The chemical formula of the vinyl siloxane monomer is Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, and the vinyl content is 3%; The structural formula of the hydrogen-containing silicone oil monomer is Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, and the hydrogen content is 0.5%.

[0008] Further, the olefin monomer is selected from one or more of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl acrylate, vinyl acetate, propylene, butadiene.

[0009] Further, the vinyl aromatic monomer is selected from one or more of styrene, 1-methylvinylbenzene, divinylbenzene.

[0010] Further, the mass of the hydrogen-containing siloxane monomer is 3%-10% of the total mass of the dendritic structure silicone resin prepared.

[0011] Further, the mass ratio of the vinyl siloxane monomer to the unsaturated double bond organic monomer is 9-11:1.

[0012] A preparation method of a dendritic cross-linked structure fluorine-free oil repellent, comprising the following steps: S1: under inert gas protection, mix the vinyl siloxane monomer, the unsaturated double bond organic monomer, and the initiator, and perform a polymerization reaction to obtain a mixed liquid; by unsaturated bond addition reaction, branched organic groups are introduced on the siloxane backbone to form a preliminary branched structure.

[0013] S2: hydrogen-containing siloxane monomers and catalysts are added to the mixed liquid in step S1, and the reaction is carried out after heating, and after the reaction is completed, post-treatment is performed to obtain a dendritic structure silicone resin, which is configured into a dendritic cross-linked structure fluorine-free oil repellent using a solvent. Through the reaction, more methyl groups are introduced at the end of the dendritic structure, the cross-linked molecular weight is controlled, and a dendritic structure silicone resin with a certain viscosity is formed.

[0014] Further, the inert gas in step S1 is selected from one or more of nitrogen and argon; The initiator in step S1 is selected from one or both of azobisisobutyronitrile and benzoyl peroxide; The mass of the initiator is 0.1%-0.5% of the total mass of the vinyl siloxane monomer, the hydrogen-containing siloxane monomer and the unsaturated double bond organic monomer; The temperature for the polymerization reaction in the temperature rising in step S1 is 50-100℃; The time for the polymerization reaction in the temperature rising in step S1 is 1-5h.

[0015] Further, the catalyst in step S2 is chloroplatinic acid; The reaction temperature for the reaction of the hydrogen-containing siloxane monomer and the catalyst in step S2 is 30-50℃, and the reaction time is 3-6h; The mass of the catalyst is 0.03%-0.1% of the total mass of the vinyl siloxane monomer, the hydrogen-containing siloxane monomer and the unsaturated double bond organic monomer.

[0016] Further, the post-treatment in step S2 includes performing vacuum distillation on the reaction product; The mass fraction of the dendritic structure silicon resin in the dendritic cross-linking structure fluorine-free oil-proof agent prepared in step S2 is 4-10%.

[0017] The dendritic cross-linking structure fluorine-free oil-proof agent prepared by the preparation method of the dendritic cross-linking structure fluorine-free oil-proof agent comprises a solvent and a dendritic structure silicon resin.

[0018] Further, the solvent comprises one or more of toluene, xylene, acetone and trichloropropane.

[0019] The vinyl siloxane monomer is vinyl silicone oil; The hydrogen-containing siloxane monomer is hydrogen-containing silicone oil.

[0020] Compared with the prior art, the dendritic structure oil-repellent agent has a highly branched dendritic macromolecular structure with silicon atoms as the core and connected by silicon-oxygen bonds. In the molecular structure, a small amount of side group hydrogen-containing silicone oil is added, which increases the cross-linking degree of the oil-repellent agent and a large number of methyl groups. The vinyl silicone oil serves as the reaction main body, so that the oil-repellent agent contains a small amount of cross-linkable groups. The addition of the unsaturated double bond organic monomer endows the silicon resin with certain affinity to different substrates, promotes the directional arrangement of the CH3 groups outward, and enhances the oil-repellent property of the silicon resin. At the same time, the unsaturated double bond organic monomer can further participate in the chemical reaction, and is secondarily cross-linked by heating in the post-treatment process, thereby improving the oil-repellent property of the material.

[0021] Compared with the prior art, the dendritic cross-linking structure fluorine-free oil-proof agent and the preparation method thereof have the following advantages: 1. The dendritic structure silicone resin of the present application has excellent comprehensive performance by virtue of unique molecular structure design and combination of the advantages of dendritic polymers and silicone resins. High heat resistance enables it to be used stably at high temperature; good flexibility and high mechanical strength enable it to have better adaptability in different application scenarios; and low surface tension and good adhesion to various substrates enable it to be widely applied to surface treatment of various materials.

[0022] 2. The preparation method of the present application is simple, easy to operate, and has mild reaction conditions, without the need for special equipment and complex process steps, and is suitable for industrial large-scale production. Meanwhile, by precisely controlling the reaction conditions, the molecular structure and performance of the dendritic structure silicone resin can be accurately controlled, thereby ensuring the stability and consistency of product quality. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The present application is not limited by the accompanying drawings. Figure 1 The schematic diagram of contact angle change of the coating angle of the dendritic cross-linked structure fluorine-free oil repellent prepared in Example 1 (a is the contact angle of water on the material without coating the dendritic cross-linked structure fluorine-free oil repellent, the contact angle is 64.1°, b is the contact angle of water on the material coated with the dendritic cross-linked structure fluorine-free oil repellent prepared in the example, the contact angle is 124.6°, c is the contact angle of olive oil on the material without coating the dendritic cross-linked structure fluorine-free oil repellent, the contact angle is 0°, d is the contact angle of olive oil on the material coated with the dendritic cross-linked structure fluorine-free oil repellent prepared in the example, the contact angle is 90.2°); Figure 2 The schematic diagram of propylene glycol effect of blank PP film, propylene glycol effect of Example 1 treated PP film, glycerol effect of blank PP film, glycerol effect of Example 1 treated PP film, soap water effect of blank PP film, soap water effect of Example 1 treated PP film (A is the propylene glycol effect of blank PP film, the contact angle is 45.42°, B is the propylene glycol effect of Example 1 treated PP film, the contact angle is 48.375°, C is the glycerol effect of blank PP film, the contact angle is 64.474°, D is the glycerol effect of Example 1 treated PP film, the contact angle is 100.675°, E is the soap water effect of blank PP film, the contact angle is 102.764°, F is the soap water effect of Example 1 treated PP film, the contact angle is 118.542°); Figure 3 The spectral analysis diagram of the dendritic cross-linked structure fluorine-free oil repellent of Example 1 of the present application. DETAILED DESCRIPTION

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] The hydrogen-containing silicone oil was purchased from Dow Corning (Zhangjiagang) Organosilicon Co., Ltd.

[0027] The vinyl silicone oil was purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd.

[0028] Example 1: Step 1: Under nitrogen protection, add 150g of vinyl silicone oil (vinyl siloxane monomer, structural formula Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, vinyl content 3%), molecular weight 1000, 15g of styrene, and 0.5g of azobisisobutyronitrile to a reactor equipped with a stirrer, thermometer, and reflux condenser. Heat to 70℃ and react for 5 hours.

[0029] Step 2: Add 8g of hydrogen-containing silicone oil (the structural formula of the hydrogen-containing silicone oil monomer is Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, with a hydrogen content of 0.5%), a molecular weight of 1000, a Si-H content of 1.5mmol / g, and 0.1g of chloroplatinic acid catalyst to the above reaction system, control the temperature at 40℃ and react for 4 hours.

[0030] Step 3: After the reaction is complete, the reaction product is subjected to vacuum distillation to remove solvent and unreacted monomers and other small molecule impurities to obtain dendritic silicone resin. Then, 5 grams of the obtained dendritic silicone resin is taken and 95 grams of trichloropropane are added to prepare a 5% (w / w) solution of dendritic silicone resin to obtain a dendritic cross-linked fluorine-free oil repellent.

[0031] The contact angle change of the dendritic cross-linked non-fluorinated oil repellent prepared in Example 1 (e.g., the coating angle of the oil repellent). Figure 1 As shown, a represents the contact angle of water on the material without the dendritic cross-linked fluorine-free oil repellent coating, which is 64.1°; b represents the contact angle of water on the material coated with the dendritic cross-linked fluorine-free oil repellent prepared in the example, which is 124.6°; c represents the contact angle of olive oil on the material without the dendritic cross-linked fluorine-free oil repellent coating, which is 0°; and d represents the contact angle of olive oil on the material coated with the dendritic cross-linked fluorine-free oil repellent prepared in the example, which is 90.2°. Figure 2Blank PP film propylene glycol effect, Example 1 treated PP film propylene glycol effect, blank PP film glycerol effect, Example 1 treated PP film glycerol effect, blank PP film soapy water effect, Example 1 treated PP film soapy water effect, wherein A is blank PP film propylene glycol effect, the contact angle is 45.42°, B is Example 1 treated PP film propylene glycol effect, the contact angle is 48.375°, C is blank PP film glycerol effect, the contact angle is 64.474°, D is Example 1 treated PP film glycerol effect, the contact angle is 100.675°, E is blank PP film soapy water effect, the contact angle is 102.764°, F is Example 1 treated PP film soapy water effect, the contact angle is 118.542°.

[0032] As shown in Figure 3 3081cm -1 , 2949cm -1 , 2923cm -1 is the stretching vibration absorption peak of benzene ring, 2173cm -1 is the stretching vibration absorption peak of hydrogen (-Si-H) bond, 1131cm -1 and 1093cm -1 are the bending vibration absorption peaks of -Si-O-C. The infrared analysis results prove that the dendritic structure is generated after the reaction of vinyl siloxane with hydrogen-containing siloxane and styrene, 2173cm -1 the stretching vibration absorption peak of hydrogen (-Si-H) bond disappears, and there are strong absorption peaks at 3081cm -1 , 2949cm -1 , 2923cm -1 , the reaction of vinyl siloxane with hydrogen-containing siloxane occurs, and styrene is successfully connected to the dendritic molecular chain.

[0033] Example 2: First step: under the protection of argon, 150g of vinyl silicone oil (vinyl siloxane monomer, the structural formula is Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, the vinyl content is 3%, the molecular weight is 1000), 50g of styrene, 0.5g of azobisisobutyronitrile are added into a reaction kettle equipped with a stirrer, a thermometer and a reflux condenser, and the temperature is raised to 70℃, and the reaction is carried out for 5 hours.

[0034] Second step: 5g of hydrogen-containing silicone oil (the structural formula of hydrogen-containing silicone oil monomer is Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, the hydrogen content is 0.5%, the molecular weight is 1000, the Si-H content is 1.5mmol / g), 0.1g of chloroplatinic acid catalyst are added into the above reaction system, the temperature is controlled at 40℃, and the reaction is carried out for 3-6 hours.

[0035] After the reaction is completed, the reaction product is subjected to reduced pressure distillation to remove the solvent and unreacted monomers and the like to obtain a dendritic structure silicone resin. Then, 5 g of the obtained dendritic structure silicone resin is added to 95 g of trichloropropane to prepare a solution of the dendritic structure silicone resin having a mass fraction of 5%, thereby obtaining a dendritic crosslinked structure fluorine-free oil repellent.

[0036] Example 3: First step: 150 g of vinyl silicone oil (vinyl siloxane monomer, structural formula: Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, vinyl content: 3%), molecular weight: 1000, 15 g of butyl acrylate, and 0.5 g of azobisisobutyronitrile are added to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser under nitrogen protection, and the temperature is raised to 70°C, and the reaction is performed for 5 hours.

[0037] Second step: 16 g of hydrogen-containing silicone oil (hydrogen-containing silicone oil monomer, structural formula: Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, hydrogen content: 0.5%), molecular weight: 1000, Si-H content: 1.5 mmol / g, and 0.1 g of chloroplatinic acid catalyst are added to the above reaction system, and the temperature is controlled at 40°C, and the reaction is performed for 3-6 hours.

[0038] Third step: After the reaction is completed, the reaction product is subjected to reduced pressure distillation to remove the solvent and unreacted monomers and the like to obtain a dendritic structure silicone resin. Then, 5 g of the obtained dendritic structure silicone resin is added to 95 g of trichloropropane to prepare a solution of the dendritic structure silicone resin having a mass fraction of 5%, thereby obtaining a dendritic crosslinked structure fluorine-free oil repellent.

[0039] Example 4: First step: 150 g of vinyl silicone oil (vinyl siloxane monomer, structural formula: Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, vinyl content: 3%), molecular weight: 3000, 15 g of styrene, and 0.5 g of azobisisobutyronitrile are added to a reaction kettle equipped with a stirrer, a thermometer, and a reflux condenser under nitrogen protection, and the temperature is raised to 70°C, and the reaction is performed for 5 hours.

[0040] Second step: 8 g of hydrogen-containing silicone oil (hydrogen-containing silicone oil monomer, structural formula: Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, hydrogen content: 0.5%), molecular weight: 3000, Si-H content: 1.5 mmol / g, and 0.05 g of chloroplatinic acid catalyst are added to the above reaction system, and the temperature is controlled at 40°C, and the reaction is performed for 3-6 hours.

[0041] Third step: After the reaction, the reaction product was subjected to reduced pressure distillation to remove the solvent and unreacted monomers and other small molecular impurities to obtain the dendritic structure silicone resin. Then, 5 grams of the obtained dendritic structure silicone resin was added to 95 grams of trichloropropane to prepare a solution with a mass fraction of 5% of the dendritic structure silicone resin, thereby obtaining the dendritic cross-linked structure fluorine-free oil repellent.

[0042] Example 5 First step: Under nitrogen protection, 150 grams of vinyl silicone oil (vinyl siloxane monomer, structural formula: Vi-(Me2SiO)m(Vi-MeSiO)nSiMeVi, vinyl content 3%, molecular weight 1000), 15 grams of butyl acrylate, and 0.738 grams of benzoyl peroxide were added to a reaction kettle equipped with a stirrer, thermometer, and reflux condenser, and the temperature was raised to 70°C, and the reaction was carried out for 5 hours.

[0043] Second step: 8 grams of hydrogen-containing silicone oil (hydrogen-containing silicone oil monomer, structural formula: Me3SiO(Me2SiO)m(MeHSiO)nSiMe3, hydrogen content 0.5%, molecular weight 1000, Si-H content 1.5 mmol / g, and 0.1 grams of chloroplatinic acid catalyst were added to the above reaction system, and the temperature was controlled at 40°C, and the reaction was carried out for 4 hours.

[0044] Third step: After the reaction, the reaction product was subjected to reduced pressure distillation to remove the solvent and unreacted monomers and other small molecular impurities to obtain the dendritic structure silicone resin. Then, 5 grams of the obtained dendritic structure silicone resin was added to 95 grams of trichloropropane to prepare a solution with a mass fraction of 5% of the dendritic structure silicone resin, thereby obtaining the dendritic cross-linked structure fluorine-free oil repellent.

[0045] Comparative Example 1 A commercially available ordinary silicone resin was purchased, model RSN-0749.

[0046] Comparative Example 2 The difference from Example 1 is that the molecular weight of the vinyl silicone oil is changed to 10000, and the other reaction conditions remain unchanged to prepare the dendritic structure silicone resin, and the reaction appears to be agglomerated and cannot form a stable solution.

[0047] Comparative Example 3 The difference from Example 1 is that the molecular weight of the hydrogen-containing silicone oil is 5000, and the reaction conditions remain unchanged to prepare the dendritic structure silicone resin, and the reaction appears to be agglomerated and cannot form a stable solution.

[0048] Comparative Example 4 The difference from Example 1 is that the molecular weight of the vinyl silicone oil is 800; The molecular weight of the hydrogen-containing silicone oil is 1000; The cross-linking degree is lower than that of Example 1, and the reaction product has poor oil-repellent properties.

[0049] Comparative Example 5 The difference from Example 1 is that the molecular weight of the vinyl silicone oil is 4000; The molecular weight of the hydrogen-containing silicone oil is 1000; The cross-linking degree of the reaction is too high, the viscosity of the product is large, it is not easy to dissolve, it cannot form a uniform solution, and the oil-repellent performance of the PTFE film is not uniform.

[0050] Comparative Example 6 The difference from Example 1 is that the molecular weight of the vinyl silicone oil is 1000; The molecular weight of the hydrogen-containing silicone oil is 4000; The cross-linking degree is increased, the reaction is not easy to control, and agglomeration is easy to occur, and the performance of the treated film is not uniform.

[0051] Comparative Example 7 The difference from Example 1 is that the molecular weight of the vinyl silicone oil is 1000; The molecular weight of the hydrogen-containing silicone oil is 800; The cross-linking degree is very small, and the product has no oil-repellent property.

[0052] Performance test 1. Water and oil repellency test: Sample preparation: A certain amount of samples of Examples 1-5 and Comparative Examples 1-7 were coated on PTFE film, and after coating, the samples were heated and cured at 100°C for 30 minutes.

[0053] Test method: 1) The sample piece (both sides of the inner hole film can contact the solution) was immersed in water, hand soap, shampoo, and vegetable oil; 2) After immersion for 10H, the sample was tested for appearance and function. The effect of Examples 1-5 and Comparative Examples 1-7 of different A, B, and C batches is shown in Table 1.

[0054] Table 1 Effect of Examples 1-5 and Comparative Examples 1-7 of different A, B, and C batches; ; Water drop angle and oil drop angle test: The sample for the liquid drop angle test is a PP film, the test condition is instantaneous liquid drop angle, and the contact angle test is performed using a JC2000D5 type contact angle tester. Before the experiment, the injection needle was completely immersed in deionized water or n-hexadecane, and the injection process was observed to observe whether there were air bubbles in the syringe; the water or oil droplets were dropped on the substrate surface using a syringe, and after the droplets were stable, the contact angle formed by the droplets was recorded by taking a picture using the instrument. In order to test the accuracy, 3-5 points were measured for each coating, and the average value was calculated, as shown in Table 2.

[0055] Table 2 Effectiveness table of water, propylene glycol, olive oil, n-hexadecane for Examples 1-5, Comparative Examples 1-7; ; The greater the contact angle, the closer the droplet is to a perfect sphere, indicating weaker interaction of the liquid with the surface, and better lyophobicity / liquid repellency of the surface.

[0056] The original PP breathable film (without treatment) has a contact angle of 70° for water (with some hydrophobicity), but 0° for all organic liquids (propylene glycol, olive oil, n-hexadecane) (completely wet), completely oleophilic, no oil repellency. This is a typical characteristic of low surface energy polyolefin materials, whose surface energy is higher than the surface tension of organic liquids.

[0057] Examples 1, 3, 4, 5 have water contact angles >125°, reaching superhydrophobic standards, Example 2 has excellent water repellency (114°) and propylene glycol repellency (100°), but is completely wetted by olive oil and n-hexadecane (0°), this treatment only improves the material's protection against medium surface tension liquids.

[0058] Comparative Examples 2, 3, 4, 7, all liquid contact angle data are completely consistent with the untreated PP film, these treatment processes have no effect at all, and fail to change the surface chemistry or topography of the PP film.

[0059] Comparative Examples 1, 5 only have moderate hydrophobicity (water contact angle 100°) performance, and are completely wetted by all organic liquids. The treatment process only slightly improves water repellency, but far from reaching superhydrophobic levels, and completely fails to impart oil repellency to the material. It may only introduce some roughness or weak hydrophobic groups, but not enough to resist organic liquids.

[0060] Comparative Example 6 has superhydrophobic (125°) performance, can resist olive oil (115°), but will be wetted by propylene glycol and n-hexadecane.

[0061] 3. Temperature resistance test; Test method: PI films treated with fluorine-free oil repellent prepared from Examples 1-5 and blank PI films are placed in an oven at the same time, heated at 300°C for 30 minutes.

[0062] 1) Observe the infiltration with propylene glycol; 2) Test the weight loss; Table 3 Weight loss table of Examples 1-5; Sample No soak Soak with 30 min Weight loss after warming Example 1 No soak No soak 0 Example 2 Soak Soak 0 Example 3 No soak No soak 0 Example 4 No soak No soak 0 Example 5 No soak No soak 0 Blank PI film Soak Soak 0 The PI film did not lose its oleophobic properties after being heated at 300℃ for 30 minutes. The PI film treated with the fluorine-free oleophobic agent did not experience weight loss or wetting after being heated at 300℃ for 30 minutes, indicating that the fluorine-free oleophobic agent is stable at 300℃.

[0063] Through the comparison of the above embodiments and comparative examples, it can be clearly seen that the dendritic structure silicone resin of the present invention has significant advantages in performance. Its preparation method is simple and feasible, and its application effect is good, with broad application prospects and market value.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a dendritic cross-linked fluorine-free oil repellent, characterized in that: The process includes the following steps: copolymerizing vinylsiloxane monomers, hydrogen-containing siloxane monomers, and unsaturated double-bonded organic monomers to obtain a dendritic silicone resin; mixing the dendritic silicone resin with a solvent to obtain a dendritic cross-linked fluorine-free oil repellent. The molecular weight of vinylsiloxane monomers is 1000-3000; The molecular weight of hydrogen-containing siloxane monomers is 1000-3000; The unsaturated double bond organic monomer is any one or a combination of vinyl aromatic monomers or olefin monomers.

2. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 1, characterized in that: The olefin monomers are selected from one or more of methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl acrylate, vinyl acetate, propylene, and butadiene.

3. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 1, characterized in that: The vinyl aromatic monomers are selected from one or more of styrene, 1-methylvinylbenzene, and divinylbenzene.

4. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 1, characterized in that: The mass of the hydrogen-containing siloxane monomer is 3%–10% of the total mass of the prepared dendritic silicone resin.

5. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 1, characterized in that: The mass ratio of vinylsiloxane monomer to unsaturated double-bonded organic monomer is 9-11:

1.

6. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 1, characterized in that: Includes the following steps: S1: Under inert gas protection, vinylsiloxane monomer, unsaturated double bond organic monomer and initiator are mixed and heated to carry out polymerization reaction to obtain a mixture; S2: Add hydrogen-containing siloxane monomers and catalysts to the mixture in step S1 and heat to react. After the reaction is completed, perform post-treatment to obtain dendritic silicone resin, and use solvent to prepare a dendritic cross-linked structure fluorine-free oil repellent.

7. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 6, characterized in that: The inert gas in step S1 is selected from one or more of nitrogen and argon; The initiator in step S1 is selected from one or both of azobisisobutyronitrile and benzoyl peroxide; The mass of the initiator is 0.1%–0.5% of the total mass of the vinylsiloxane monomer, the hydrogen-containing siloxane monomer, and the unsaturated double-bonded organic monomer; The temperature for the polymerization reaction in step S1 is 50-100℃; The time for the polymerization reaction in step S1 is 1-5 hours.

8. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 6, characterized in that: The catalyst in step S2 is chloroplatinic acid; In step S2, the reaction temperature for the hydrogen-containing siloxane monomer and catalyst is 30-50℃, and the reaction time is 3-6h. The mass of the catalyst is 0.03%–0.1% of the total mass of vinylsiloxane monomers, hydrogen-containing siloxane monomers, and unsaturated double-bonded organic monomers.

9. The method for preparing a dendritic cross-linked fluorine-free oil repellent according to claim 6, characterized in that: The post-processing in step S2 includes distilling the reaction product under reduced pressure. The dendritic cross-linked fluorine-free oil repellent prepared in step S2 has a dendritic silicone resin mass fraction of 4-10%.

10. A dendritic cross-linked fluorine-free oil repellent prepared by the method according to any one of claims 6-9, characterized in that: Dendritic cross-linked fluorine-free oil repellents include solvents and dendritic silicone resins.

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