Fluorine-free oil-proof agent as well as preparation method and application thereof

Abstract

The invention provides a fluoride-free oil-proof agent as well as a preparation method and application thereof, and belongs to the technical field of textile assistants. The fluorine-free oil-proof agent is prepared by reacting a fluorine-free oleophobic monomer with hydrophobic silica aerogel particles, the fluorine-free oleophobic monomer has an umbrella-shaped liquid-like characteristic, and the hydrophobic silica aerogel particles have a three-dimensional porous network structure. The fluoride-free oil-proof agent can endow the fabric with a good oil-proof effect.

Description

Technical Field

[0001] The present application relates to a fluorine-free oil-proofing agent and a preparation method and application thereof, belonging to the technical field of textile auxiliaries. Background Art

[0002] For a long time, fluorinated finishing agents based on perfluoro / polyfluoroalkyl structures have been widely used in the fields of textiles, leather, papermaking, and medical treatment due to their excellent water and oil repellency. However, the processing and use of traditional fluorinated water and oil repellents often involve the emission of toxic and harmful compounds, posing a huge threat to human health and environmental ecology. The European Union and parts of North America are expected to completely ban the production and use of fluorinated water and oil repellents starting in 2025. In 2023, my country also clearly included perfluorooctanoic acid, perfluorooctane sulfonic acid, and perfluorohexane sulfonic acid compounds in the "List of New Pollutants under Key Control".

[0003] Since non-fluorine substances tend to have higher surface energy, most of the fluorine-free water repellents currently on the market do not have oil repellency. Research on fluorine-free oil repellents for textiles is still in its infancy. In the paper "Non-fluorine oil repellency: to what extent can it substitute perfluoroalkyl substances", Zhao Yan used chemical vapor deposition technology to covalently graft polydimethylsiloxane (PDMS) molecular brushes on the surface of nylon fibers, which can prevent the diffusion and penetration of low surface energy droplets such as edible oil and hexadecane in fabrics to a certain extent, but vapor deposition technology cannot be applied on a large scale and at low cost in the textile industry. In the paper "Fluorine-free low surface energy organic coating for anti-stain applications", Zhuang Qixin reported that depositing acrylate polymers on the fiber surface and introducing tris(trimethylsiloxane) silane groups can give textile materials a certain oleophobic effect.

[0004] In addition, the surface microscopic roughness has an important influence on the surface wettability. Doris Vollmer reported in the paper "Fluorine-free super-liquid-repellent surfaces: pushing the limits of PDMS" that a fluorine-free super-liquid-repellent surface was obtained by constructing a binary porous microscopic rough structure using nano-spherical particles modified with PDMS. Zhao Kai introduced cage-type polysilsesquioxane into the molecular design of fluorine-free oil repellent agents, and then constructed a nano-scale rough structure on the fiber surface. The finished fabric has a certain oil-proof effect.

[0005] However, the above products cannot achieve the ideal oil-proof effect, especially for the "complete defluorination" requirement of waterproof and oil-proof agents used in the textile industry. The current research results cannot meet the industry's needs for oil-proof effect and defluorination. It is imperative to research and develop fluorine-free oil-proof agents with better oil-proof effect. Summary of the invention

[0006] In view of this, the present application first provides a fluorine-free oil-proof agent, which not only achieves fluorine-free chemical composition, but also gives the finished fabric good oil-proof properties.

[0007] Specifically, the present application is implemented through the following scheme: A fluorine-free oil-proofing agent is prepared by reacting a fluorine-free oleophobic monomer with hydrophobic silica aerogel particles, wherein the fluorine-free oleophobic monomer has an umbrella-like liquid characteristic, and the hydrophobic silica aerogel particles have a three-dimensional porous network structure.

[0008] The above-mentioned fluorine-free oil-proof agent not only does not introduce fluorine components, but is endowed with fluorine-free monomers with umbrella-like liquid properties and silica aerogel particles with a three-dimensional network structure. Its umbrella-like liquid properties can effectively prevent common edible oils from penetrating into fabrics, while the three-dimensional network structure can construct a rough structure on the fiber surface, thereby further improving the oil-proof effect of the fluorine-free oil-proof agent.

[0009] Further, as a preference: The fluorine-free oleophobic monomer is methacryloxypropyl T-structure polysiloxane or methacryloxypropyl functionalized polydimethylsiloxane.

[0010] The hydrophobic silica aerogel particles have a three-dimensional porous network structure and have a methacryloxypropyl or acryloxypropyl group on the surface, and can be prepared by an acid-base two-step catalytic sol-gel method. As a specific method, the hydrophobic silica aerogel particles are prepared in the following manner: under stirring conditions, methyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are added to methanol, and then oxalic acid is slowly added to the above solution and the reaction is continued after stirring, and then ammonia water is added dropwise, and the reaction vessel is sealed and gelled. After the gelation is completed, a small amount of methanol is added to the reaction vessel as a mother liquor to continue the aging treatment, and finally the pulverization treatment is carried out. After the supercritical carbon dioxide fluid is dried, silica aerogel particles with a three-dimensional porous network structure are obtained.

[0011] The second object of the applicant is to provide a method for preparing a fluorine-free oil-proofing agent, which is prepared by a mini-emulsion polymerization method, and the steps are as follows: Step 1, weighing a cationic emulsifier and a nonionic emulsifier, stirring them evenly and dissolving them in deionized water, and adjusting the pH value of the solution to 3-6 to obtain an emulsifier aqueous solution; Step 2, weighing the fluorine-free oil-proof monomer with an umbrella-like liquid structure, the silica aerogel particles with a three-dimensional porous network structure, and the functional monomer respectively, dispersing the three in a co-solvent, and slowly adding the obtained dispersion into the emulsifier aqueous solution to obtain a mixed dispersion; Step 3, first disperse the mixed dispersion to obtain a coarse emulsion, then ultrasonically treat the coarse emulsion to obtain a fine emulsion, then add an initiator dissolved in deionized water in advance, heat to 70 ° C, stir and react for 5 to 20 hours, filter the liquid, and obtain a fluorine-free oil repellent; The added mass percentages of the above materials are: Fluorine-free oleophobic monomer: 20-50%, Hydrophobic silica aerogel particles: 2~5%, Functional monomer 0.5~4 %, Solvent 0~2 %, Cationic emulsifier and nonionic emulsifier: 2-5%, Initiator: 0.002~1 %, Deionized water: 40-70%.

[0012] In the above preparation process, the fluorine-free oleophobic monomer has an umbrella-like liquid characteristic, including methacryloxypropyl T-structured polysiloxane or methacryloxypropyl functionalized polydimethylsiloxane. The use of such monomers can form a large number of PDMS segments with umbrella-like liquid structures on the fiber surface, and at the same time, the monomer is rich in a large number of methyl groups to reduce the surface free energy of the fiber. The hydrophobic silica aerogel particles have a three-dimensional porous network structure and have a large number of methacryloxypropyl or acryloxypropyl groups on their surface. The purpose of adding hydrophobic silica aerogel particles is mainly to construct a rough structure on the fiber surface and enhance the oil-proof effect of the oil-proof agent.

[0013] Preferred: The functional monomer contains a copolymerizable methacrylate or acrylate group. More preferably, the functional monomer also contains at least one functional group selected from epoxy, hydroxyl, amino, carboxyl or ketocarbonyltrialkoxysilyl. The functional monomer is a functional monomer containing both a copolymerizable methacrylate or acrylate group and a reactive group such as epoxy, hydroxyl, amino, carboxyl or ketocarbonyltrialkoxysilyl. Such as: glycidyl methacrylate, hydroxyethyl methacrylate, methacrylic acid, methacrylamide, N-vinyl pyrrolidone, etc. The addition of the functional monomer increases the direct bonding strength between the fluorine-free oil-proofing agent and the textile material, and improves the durability of the fluorine-free oil-proofing of the fabric.

[0014] The cationic emulsifier is any one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and hexadecyltrimethylammonium chloride, or a mixture of more than one of the above.

[0015] The nonionic emulsifier is any one of fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether, Span-80, and polyethylene glycol monolaurate, or a mixture of more than one of them.

[0016] The pH value is adjusted by using a pH adjuster, the addition amount of which is 0-1.5%, and the pH adjuster is preferably glacial acetic acid.

[0017] The initiator is any one of azobisisobutylamidine hydrochloride (2,2'-azobisisobutylamidine hydrochloride), azobisisobutylimidazoline hydrochloride, dimethyl azobisisobutyrate, potassium persulfate, and azobisisobutyronitrile, or a mixture of more than one of the above.

[0018] The third purpose of the applicant is to provide an application of the above-mentioned fluorine-free oil-proofing agent, which is used for textile finishing.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) At present, most of the fluorine-free water-repellents on the market do not have the oil-proof function. The present invention uses a fluorine-free oil-proof monomer with an umbrella-like liquid structure to prepare a fluorine-free oil-proof agent, which can give textiles a better oil-proof effect.

[0020] (2) The fluorine-free oil repellent in the present invention is added with silica aerogel particles having a three-dimensional porous network structure, which can construct a rough structure at the micro-nano level on the fiber surface, giving the textile a better oil repellent effect.

[0021] (3) The preparation method of the fluorine-free oil repellent provided by the present invention has a simple process, is easy to implement and control, and is conducive to popularization and application.

[0022] (4) With this fluorine-free oil-proof agent, textiles can obtain the ideal fluorine-free oil-proof effect through a simple dipping-rolling-baking process, which has broad application prospects in the field of waterproof and oil-proof textile processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The silica aerogel particles having a three-dimensional porous network structure in this application; Figure 2 This is a comparison chart of the oil-proof effect of the fabric before and after finishing in Example 2 of the present application. DETAILED DESCRIPTION

[0024] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0025] Those not specified are conventional commercial preparations.

[0026] Example 1

[0027] The present embodiment is a fluorine-free oil repellent, which is prepared by the following method: Step 1: Add 80 mL of methyltrimethoxysilane and 40 mL of γ-methacryloxypropyltrimethoxysilane to 685 mL of methanol under stirring conditions, then slowly add 50 mL of oxalic acid (0.01 M) to the above solution and continue stirring for 24 h, then add 50 mL of ammonia water (10 M) dropwise to the above solution under stirring conditions, seal the reaction vessel and place it at 50 °C for gelation. After the gelation is completed, add a small amount of methanol as the mother liquor to the reaction vessel for further 48 h of aging treatment, and finally use a homogenizer and an ultrasonic centrifuge to crush the silica gel. After supercritical carbon dioxide fluid drying, a three-dimensional porous network structure of silica aerogel particles is obtained, and its structure is as follows: Figure 1 shown.

[0028] Step 2: weigh 3 g of a cationic emulsifier, octadecyltrimethylammonium chloride, and 18 g of a nonionic emulsifier, fatty alcohol polyoxyethylene ether, and dissolve them in 460 g of deionized water after stirring evenly, and add glacial acetic acid to adjust the pH to about 4 to obtain an emulsifier solution.

[0029] Step 3: Weigh 220 g of methacryloxypropyl functionalized polydimethylsiloxane (MCS-M11, Gelest, USA), 25 g of silica aerogel particles prepared by the method of step 1, and 20 g of hydroxyethyl methacrylate and disperse them in 70 g of tripropylene glycol. Slowly add the obtained dispersion to the emulsifier solution prepared by the method of step 2 to obtain a mixed dispersion.

[0030] Step 4: Use a disperser to disperse the mixed dispersion to obtain a coarse emulsion, then ultrasonically treat the coarse emulsion in a cell crusher to obtain a fine emulsion, then add an aqueous solution containing 2.5 g of initiator 2,2'-azobisisobutylamidine hydrochloride, heat to 70°C, stir and react for 8 hours, and filter the liquid to obtain an emulsion-like fluorine-free oil repellent.

[0031] Comparative Example 1

[0032] The configuration of this comparative example is the same as that of Example 1, except that no silica aerogel particles having a three-dimensional porous network structure are added.

[0033] Comparative Example 2

[0034] This comparative example has the same configuration as Example 1, except that 220 g of methacryloxypropyl functionalized polydimethylsiloxane is replaced with 230 g of octadecyl methacrylate.

[0035] Comparative Example 3

[0036] The configuration of this comparative example is the same as that of Example 1, except that 20 g of hydroxyethyl methacrylate is not added.

[0037] Example 2

[0038] The present embodiment is a fluorine-free oil repellent, which is prepared by the following method: Step 1: 80 mL of methyltrimethoxysilane and 40 mL of γ-methacryloxypropyltrimethoxysilane were added to 685 mL of methanol under stirring, and then 50 mL of oxalic acid (0.01 M) was slowly added to the above solution and continued to stir for 24 h, and then 50 mL of ammonia water (10 M) was added dropwise to the above solution under stirring, and then the reaction container was sealed and placed at 50 ° C for gelation. After the gelation was completed, a small amount of methanol was added to the reaction container as the mother liquor and the aging treatment was continued for 48 h. Finally, the silica gel was crushed using a homogenizer and an ultrasonic centrifuge, and the silica aerogel particles with a three-dimensional porous network structure were finally obtained after supercritical carbon dioxide fluid drying.

[0039] Step 2: weigh 3 g of a cationic emulsifier, octadecyltrimethylammonium chloride, and 18 g of a nonionic emulsifier, fatty alcohol polyoxyethylene ether, and dissolve them in 460 g of deionized water after stirring evenly, and add glacial acetic acid to adjust the pH to about 4 to obtain an emulsifier solution.

[0040] Step 3: Weigh 250 g of methacryloxypropyl T-structured polysiloxane (RTT-1011, Gelest, USA), 25 g of silica aerogel particles prepared by the method in step 1, and 25 g of glycidyl methacrylate and disperse them in tripropylene glycol. Slowly add the obtained dispersion into the emulsifier solution to obtain a mixed dispersion.

[0041] Step 4: Use a disperser to disperse the mixed liquid to obtain a coarse emulsion, then ultrasonically treat the coarse emulsion in a cell crusher to obtain a fine emulsion, then add an aqueous solution containing 2.5 g of initiator 2,2'-azobisisobutylamidine hydrochloride, heat to 70°C, stir and react for 8 hours, and filter the liquid to obtain an emulsion-like fluorine-free oil repellent.

[0042] Comparative Example 4

[0043] The configuration of this comparative example is the same as that of Example 2, except that no silica aerogel particles having a three-dimensional porous network structure are added.

[0044] Comparative Example 5

[0045] This comparative example has the same configuration as Example 2, except that 25 g of glycidyl methacrylate is not added.

[0046] The oil-proofing agents prepared in Examples 1 and 2 and Comparative Examples 1, 2, 3, 4 and 5 were respectively used for fluorine-free oil-proofing of fabrics.

[0047] The oil-proof finishing process is as follows: The oil-proof agent with a solid content of 30% was prepared into a finishing working solution with a concentration of 50 g / L, and 20 g / L of a commercially available cross-linking agent (HYDROSIN C-20, Maflon SPA, Italy) was added. Cotton plain weave fabric was selected, and the finishing solution was dried at 180 °C for 2 min using a one-dip and one-roll method.

[0048] Oil droplet contact angle: Place a 5μL household olive oil droplet on the fabric surface, and use a contact angle tester to measure the oil droplet contact angle of the fabric before and after finishing. Select 5 different areas of the fabric to repeat the test, and take the average of the oil droplet contact angles of the 5 areas as the oil droplet contact angle of the fabric.

[0049] Oil-proof time: Place a 5 μl drop of household olive oil on the fabric surface and observe the time when the oil drop begins to penetrate the fabric as the oil-proof time.

[0050] Washing resistance: According to AATCC-135, the washing resistance of the fabric before and after finishing is tested. The specific standards are shown in Table 1, and the drying method is drying.

[0051] Table 1: AATCC-135 washing test standard .

[0052] The oil-proof effects of cotton plain fabrics treated with oil-proof agents obtained in each case are shown in Table 2.

[0053] Table 2: Comparison of oil-proofing effects of oil-proofing agents obtained from different schemes .

[0054] It can be seen from Table 2 that Example 1, Example 2, Comparative Example 1, and Comparative Example 4 all impart good oil-proof effects to plain cotton fabrics after oil-proof finishing, and the fluorine-free oil-proof effect of Example 2 is the best, followed by the oil-proof effect of Example 1. In Comparative Examples 1 and 4, no silica aerogel particles are added, and the rough structure of the fiber surface is not fully constructed, and the oil-proof performance is reduced.

[0055] The oil-proof effect of the fabric before and after finishing in Example 2 is as follows Figure 2 As shown: from the time the oil droplet just dropped on the fabric (t=0s) to t=1300s, and until t=2600s, the oil droplet always remained in a large granular form, and its shape did not change, which also confirms that the fluorine-free oil repellent provided in this application has a good oil repellent effect.

[0056] In Comparative Example 2, octadecyl methacrylate, which is the most widely used monomer in the market, is used as the water- and oil-proof monomer, and its oil drop contact angle is 0°, indicating that octadecyl methacrylate alone has no oil-proof effect.

[0057] Table 3: Comparison of oil-proofing effects of oil-proofing agents obtained from different schemes .

[0058] From Table 3, it can be seen that Example 1, Comparative Example 3, Example 2, and Comparative Example 5 all give the fabric a good initial oil-proof effect after oil-proof finishing of plain cotton fabric. However, after three washes, the fluorine-free oil-proof effect of the fabric in Example 1 and Example 2 is slightly weakened. In Comparative Example 2 and Comparative Example 5, no functional monomer is added, and the binding force between the fluorine-free oil-proof agent molecules and the fiber is weak, resulting in a significant decrease in the oil-proof property of the fabric after washing. Explanation: The addition of functional monomers increases the binding strength between the oil-proof agent and the textile material, which is reflected in the oil-proof performance after multiple washes.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A fluorine-free oil repellent, characterized in that: The fluorine-free oil-proofing agent is prepared by reacting a fluorine-free oleophobic monomer with hydrophobic silica aerogel particles, and the fluorine-free oleophobic monomer has an umbrella-like liquid characteristic, and the hydrophobic silica aerogel particles have a three-dimensional porous network structure.

2. A fluorine-free oil repellent according to claim 1, characterized in that: The fluorine-free oleophobic monomer is methacryloxypropyl T-structure polysiloxane or methacryloxypropyl functionalized polydimethylsiloxane.

3. A fluorine-free oil repellent according to claim 1, characterized in that: The hydrophobic silica aerogel particles have methacryloxypropyl or acryloxypropyl groups on their surfaces.

4. A method for preparing a fluorine-free oil-proofing agent, characterized in that: Here are the steps: Step 1, weighing a cationic emulsifier and a nonionic emulsifier, stirring them evenly and dissolving them in deionized water, and adjusting the pH value of the solution to 3-6 to obtain an emulsifier aqueous solution; Step 2, weighing the fluorine-free oil-proof monomer with an umbrella-like liquid structure, the silica aerogel particles with a three-dimensional porous network structure, and the functional monomer respectively, dispersing the three in a co-solvent, and slowly adding the obtained dispersion into the emulsifier aqueous solution to obtain a mixed dispersion; Step 3, first disperse the mixed dispersion to obtain a coarse emulsion, then ultrasonically treat the coarse emulsion to obtain a fine emulsion, then add an initiator dissolved in deionized water in advance, heat to 70 ° C, stir and react for 5 to 20 hours, filter the liquid, and obtain a fluorine-free oil repellent; The added mass percentages of the above materials are: Fluorine-free oleophobic monomer: 20-50%, Hydrophobic silica aerogel particles: 2~5%, Functional monomer 0.5~4 %, Solvent 0~2 %, Cationic emulsifier and nonionic emulsifier: 2-5%, Initiator: 0.002~1 %, Deionized water: 40-70%.

5. The method for preparing a fluorine-free oil-proofing agent according to claim 4, characterized in that: The functional monomer contains a copolymerizable methacrylate or acrylate group.

6. The method for preparing a fluorine-free oil-proofing agent according to claim 5, characterized in that: The functional monomer further contains at least one functional group selected from the group consisting of epoxy, hydroxyl, amino, carboxyl or ketocarbonyltrialkoxysilyl.

7. The method for preparing a fluorine-free oil-proofing agent according to claim 4, characterized in that: The functional monomer is any one of glycidyl methacrylate, hydroxyethyl methacrylate, methacrylic acid, methacrylamide, and N-vinyl pyrrolidone, or a mixture of more than one of the above.

8. The method for preparing a fluorine-free oil-proofing agent according to claim 4, characterized in that: The initiator is any one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, dimethyl azobisisobutyrate, potassium persulfate, and azobisisobutyronitrile, or a mixture of more than one of the above.

9. The method for preparing a fluorine-free oil repellent according to claim 1, characterized in that: The cationic emulsifier is any one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride or a mixture of more than one thereof; the nonionic emulsifier is any one of fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether, Span-80, polyethylene glycol monolaurate or a mixture of more than one thereof.

10. An application of the fluorine-free oil repellent according to claim 1, characterized in that: Fluorine-free oil repellent for textile finishing.

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