Fluorine-free leather water-repellent finishing agent and preparation process thereof

Abstract

The invention relates to the technical field of finishing agents, and discloses a fluoride-free leather water-repellent finishing agent and a preparation process thereof. The preparation method comprises the following steps: reacting hydrogen-containing silicone oil, N-methylallylamino hydroxypropyl alkane and a bromoalkane monomer to obtain hydroxyl quaternary ammonium salt silicone oil; the fluorine-free leather water-repellent finishing agent contains hydrophobic silicone oil and a plurality of alkyl long carbon chains, and the hydrophobic silicone oil and the alkyl long carbon chains are introduced into a polyurethane molecular chain through a polymerization chain extension reaction, so that the hydrophobic and water-repellent properties of the polyurethane finishing agent and the leather are remarkably improved, and the water-repellent property of the leather is improved. And the hydroxyl quaternary ammonium salt silicone oil contains an organosilane quaternary ammonium salt antibacterial group which is introduced into a polyurethane molecular chain, so that the finishing agent and the leather are endowed with excellent antibacterial performance.

Description

Technical Field

[0001] This invention relates to the field of finishing agents, specifically to a fluorine-free water-repellent finishing agent for leather and its preparation process. Background Technology

[0002] Leather possesses excellent strength, toughness, abrasion resistance, and breathability, making it widely used in shoes, clothing, bags, and car seat cushions. To impart good water- and oil-repellent properties and stain resistance to leather, water-repellent finishing processes are necessary. Developing novel leather finishing agents and coatings has become a research hotspot. Fluorine-containing water-repellent agents offer advantages such as low surface energy and surface tension, and strong hydrophobic properties; however, fluorine is highly toxic, difficult to degrade, and poses significant harm to human health and the environment.

[0003] Organosilicon finishing agents and coatings possess strong hydrophobic properties, high softness, and excellent antibacterial properties, making them important in leather and textile applications. Patent CN113527595B discloses a functionalized organosilicon resin, its preparation method, and its applications. The organosilicon resin prepared from polyorganosiloxanes, organosilicon quaternary ammonium salts, coumarins, and acrylates can impart antibacterial and abrasion-resistant properties to leather; however, this organosilicon resin cannot impart water-repellent properties to leather. Summary of the Invention

[0004] (I) Technical problem to be solved: In view of the shortcomings of the prior art, the present invention provides a fluorine-free water-repellent finishing agent for leather and its preparation process, which solves the problem that the existing water-repellent finishing agents contain fluorine elements, which are highly polluting and harmful, and do not have antibacterial properties.

[0005] (II) Technical Solution: Preparation Process of Fluorine-Free Leather Water-Repellent Finishing Agent:

[0006] Step S1: Add hydrogen-containing silicone oil and N-methylallylaminohydroxypropyl alkane to toluene. Add chloroplatinic acid-isopropanol catalyst dropwise under a nitrogen atmosphere, heat to 80-90℃, and stir for 4-6 hours. Then add N,N-dimethylformamide solvent and bromoalkane monomer, heat to 90-110℃, and stir for 36-48 hours. Distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl quaternary ammonium silicone oil. The reaction formula is:

[0007]

[0008] Step S2: Mix the dried polyester polyol with the diisocyanate monomer and heat it to 70-80℃ in a nitrogen atmosphere for 2-3 hours. Then add 1,4-butanediol, hydroxyquaternary ammonium salt silicone oil, dibutyltin dilaurate, and ethyl acetate. React at 50-55℃ for 1-1.5 hours. Add water to dilute, stir, and remove ethyl acetate by vacuum distillation. Add emulsifier and nano silica, stir and disperse to obtain a fluorine-free water-repellent finishing agent for leather.

[0009] Furthermore, in step S1, the ratio of hydrogen-containing silicone oil, N-methylallylaminohydroxypropyl alkane, and bromoalkane monomer is 100g:(3-8.4)g:(2.2-6.2)g.

[0010] Furthermore, the molecular formula of the bromoalkane monomer is Br-C. a H 2a+1 , where a is 10-18.

[0011] Furthermore, in step S2, the ratio of polyester polyol, diisocyanate monomer, 1,4-butanediol, hydroxy quaternary ammonium salt silicone oil, dibutyltin dilaurate, emulsifier, and nano silica is 100g:(23-29)g:(3-7)g:(8-20)g:(0.13-0.18)g:(3.6-5.2)g:(1.5-10)g.

[0012] Furthermore, the diisocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

[0013] Furthermore, the preparation process of N-methylallylaminohydroxypropyl alkane is as follows: Alkyl glycidyl ether and N-methylallylamine are added to the reaction solvent in a ratio of (220-340) g: 100 g. The mixture is heated to 40-50 °C, stirred for 4-7 h, and then distilled under reduced pressure. The product is separated by silica gel column chromatography and eluted with ethyl acetate in petroleum ether solution to obtain N-methylallylaminohydroxypropyl alkane. The reaction formula is:

[0014]

[0015] Furthermore, the reaction solvent is ethanol or isopropanol.

[0016] Furthermore, the structural formula of alkyl glycidyl ether is as follows: n is 10-18.

[0017] (III) Beneficial technical effects: This invention involves an addition reaction between N-methylallylaminohydroxypropyl alkane containing alkyl long carbon chains, hydroxyl groups, and tertiary amine groups and hydrogen-containing silicone oil. Then, the tertiary amine groups undergo a quaternization reaction with bromoalkane monomers to obtain hydroxyl quaternary ammonium salt silicone oil. Finally, it undergoes a polymerization and chain extension reaction with polyester polyols, diisocyanate monomers, etc., and is compounded with emulsifiers, nano silica, etc. to obtain a fluorine-free leather water-repellent finishing agent, which does not contain fluorine elements, which are highly polluting and harmful, and is green and environmentally friendly.

[0018] The fluorine-free water-repellent leather finishing agent of the present invention contains hydrophobic silicone oil and multiple alkyl long carbon chains, which are introduced into the polyurethane molecular chain through a polymerization chain extension reaction, significantly improving the water contact angle and hydrophobic and water-repellent properties of the polyurethane finishing agent and leather. Furthermore, the hydroxyl quaternary ammonium salt silicone oil contains organosilicon alkyl quaternary ammonium salt antibacterial groups, which are introduced into the polyurethane molecular chain, endowing the finishing agent and leather with excellent antibacterial rate and antibacterial properties. Detailed Implementation

[0019] The present application will be further described in detail below with reference to the embodiments. Unless otherwise specified, the raw materials used in the embodiments of this application are all commercially available.

[0020] The following are the product names: Polyether-modified silicone (BSM1194, Baisenmao brand); Hydrogen-containing silicone oil (JSY-484, Jishengya brand, with a hydrogen content of approximately 1.6%); Polyester polyol (TY-5132, Greenlink (Jining brand), with an average molecular weight of 2000); and Nano-silica (average particle size of 30nm).

[0021] Example 1:

[0022] (1) Add 4.7 g of dodecyl glycidyl ether (CAS Registry No. 2461-18-9) and 1.5 g of N-methylallylamine to 15 mL of isopropanol, heat to 40 °C, stir for 7 h, distill under reduced pressure, separate the product by silica gel column chromatography, and elute with ethyl acetate in petroleum ether solution to obtain N-methylallylamine hydroxypropyl alkane. The structural formula is:

[0023] (2) Add 50g of hydrogen-containing silicone oil and 1.5g of N-methylallylaminohydroxypropyl alkane to 100mL of toluene. Add 150μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 2.5mg) dropwise under a nitrogen atmosphere. Heat to 80℃ and stir for 5h. Then add 300mL of N,N-dimethylformamide solvent and 1.1g of 1-bromooctadecane. Heat to 110℃ and stir for 36h. Distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl quaternary ammonium salt silicone oil.

[0024] (3) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 70 g of 1,4-butanediol, 80 g of hydroxy quaternary ammonium salt silicone oil, 1.4 g of dibutyltin dilaurate and 400 mL of ethyl acetate, react at 50 °C for 1.5 h, add 6 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 43 g of emulsifier polyether modified organosilicon and 60 g of nano silica, stir and disperse to obtain a fluorine-free leather water-repellent finishing agent.

[0025] Example 2:

[0026] (1) Add 5.1 g octadecyl glycidyl ether and 1.5 g N-methylallylamine to 15 mL isopropanol, heat to 50 °C, stir for 4 h, distill under reduced pressure, separate the product by silica gel column chromatography, and elute with petroleum ether solution of ethyl acetate to obtain N-methylallylamine hydroxypropyl alkane.

[0027] (2) Add 50g of hydrogen-containing silicone oil and 2.7g of N-methylallylaminohydroxypropyl alkane to 80mL of toluene. Add 150μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 2.5mg) dropwise under a nitrogen atmosphere. Heat to 90℃ and stir for 4h. Then add 300mL of N,N-dimethylformamide solvent and 2.4g of 1-bromodecane. Stir for 48h at 90℃. Distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl quaternary ammonium salt silicone oil.

[0028] (3) Mix 1 kg of dry polyester polyol with 230 g of toluene-2,4-diisocyanate, heat to 80 °C in a nitrogen atmosphere, react for 2 h, then add 52 g of 1,4-butanediol, 135 g of hydroxy quaternary ammonium salt silicone oil, 1.3 g of dibutyltin dilaurate and 500 mL of ethyl acetate, react at 55 °C for 1 h, add 7 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 36 g of emulsifier polyether modified organosilicon and 15 g of nano silica, stir and disperse to obtain a fluorine-free leather water-repellent finishing agent.

[0029] Example 3:

[0030] (1) Add 3.3g n-decyl glycidyl ether and 1.5g N-methylallylamine to 10mL ethanol, heat to 40℃, stir for 5h, distill under reduced pressure, separate the product by silica gel column chromatography, and elute with petroleum ether solution of ethyl acetate to obtain N-methylallylamine hydroxypropyl alkane.

[0031] (2) Add 50g of hydrogen-containing silicone oil and 4.2g of N-methylallylaminohydroxypropyl alkane to 100mL of toluene. Add 120μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 3mg) dropwise under a nitrogen atmosphere. Heat to 90℃ and stir for 5h. Then add 400mL of N,N-dimethylformamide solvent and 3.1g of 1-bromohexadecane. Heat to 100℃ and stir for 36h. Distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl quaternary ammonium salt silicone oil.

[0032] (3) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 30 g of 1,4-butanediol, 200 g of hydroxy quaternary ammonium salt silicone oil, 1.8 g of dibutyltin dilaurate and 500 mL of ethyl acetate, react at 50 °C for 1.5 h, add 7 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 52 g of emulsifier polyether modified organosilicon and 100 g of nano silica, stir and disperse to obtain a fluorine-free leather water-repellent finishing agent.

[0033] Comparative Example 1:

[0034] (1) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 70 g of 1,4-butanediol, 1.4 g of dibutyltin dilaurate and 400 mL of ethyl acetate, react at 50 °C for 1.5 h, add 6 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 43 g of emulsifier polyether modified organosilicon and 60 g of nano silica, stir and disperse to obtain leather finishing agent.

[0035] Comparative Example 2:

[0036] (1) Add 50g of hydrogen-containing silicone oil and 1.5g of N-methylallylaminohydroxypropyl alkane (prepared according to the method of Example 1) to 100mL of toluene, add 150μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 2.5mg) dropwise under nitrogen atmosphere, heat to 80℃, stir for 5h, distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl-containing silicone oil.

[0037] (2) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 70 g of 1,4-butanediol, 80 g of hydroxyl-containing silicone oil, 1.4 g of dibutyltin dilaurate and 400 mL of ethyl acetate, react at 50 °C for 1.5 h, add 6 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 43 g of emulsifier polyether modified organosilicon and 60 g of nano silica, stir and disperse to obtain leather finishing agent.

[0038] Comparative Example 3:

[0039] (1) Add 50g of hydrogen-containing silicone oil and 1.5g of dodecene to 100mL of toluene, add 150μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 2.5mg) dropwise under nitrogen atmosphere, heat to 80℃, stir for 5h, then add 300mL of N,N-dimethylformamide solvent and 1.1g of 1-bromooctadecane, heat to 110℃, stir for 36h, distill under reduced pressure, wash the product with methanol, dry, and obtain alkyl silicone oil.

[0040] (2) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 70 g of 1,4-butanediol, 80 g of alkyl silicone oil, 1.4 g of dibutyltin dilaurate and 400 mL of ethyl acetate, react at 50 °C for 1.5 h, add 6 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 43 g of emulsifier polyether modified organosilicon and 60 g of nano silica, stir and disperse to obtain leather finishing agent.

[0041] Comparative Example 4

[0042] (1) Add 4.7 g of ethyl glycidyl ether (CAS No. 4016-11-9) and 1.5 g of N-methylallylamine to 15 mL of isopropanol, heat to 40 °C, stir for 7 h, distill under reduced pressure, separate the product by silica gel column chromatography, and elute with ethyl acetate in petroleum ether solution to obtain N-methylallylamine hydroxypropyl alkane. The structural formula is:

[0043] (2) Add 50g of hydrogen-containing silicone oil and 1.5g of N-methylallylaminohydroxypropyl alkane to 100mL of toluene. Add 150μL of chloroplatinic acid-isopropanol catalyst (chloroplatinic acid content 2.5mg) dropwise under a nitrogen atmosphere. Heat to 80℃ and stir for 5h. Then add 300mL of N,N-dimethylformamide solvent and 1.1g of 1-bromoethane (CAS No. 74-96-4). Heat to 110℃ and stir for 36h. During the reaction, reflux the solution, distill under reduced pressure, wash the product with methanol, and dry to obtain hydroxyl quaternary ammonium salt silicone oil.

[0044] (3) Mix 1 kg of dry polyester polyol with 290 g of isophorone diisocyanate, heat to 70 °C in a nitrogen atmosphere, react for 3 h, then add 70 g of 1,4-butanediol, 80 g of hydroxy quaternary ammonium salt silicone oil, 1.4 g of dibutyltin dilaurate and 400 mL of ethyl acetate, react at 50 °C for 1.5 h, add 6 L of water to dilute, stir and remove ethyl acetate by vacuum distillation, add 43 g of emulsifier polyether modified organosilicon and 60 g of nano silica, stir and disperse to obtain leather finishing agent.

[0045] Apply the leather finishing agent to the leather surface and dry and cure at 90°C for 4 hours.

[0046] Test the water contact angle of the coating according to the method specified in GB / T 30693-2014.

[0047] The leather finishing agent was poured into a mold and dried and cured at 90℃ for 4 hours to form a coating film. The antibacterial rate of the coating film was tested according to the method specified in GB / T21866-2008. Antibacterial rate = (BC) / B × 100%. B is the average number of recovered bacteria in the blank control sample over 24 hours (Comparative Example 1), and A is the average number of recovered bacteria in the antibacterial sample over 24 hours.

[0048] Table 1 Performance of Leather Finishing Agents

[0049]

[0050] As shown in the table above, compared with Comparative Example 1, the water contact angle of the fluorine-free leather water-repellent finishing agents prepared in each example reached 133.7-152.6°, and the antibacterial rate against Escherichia coli and Staphylococcus aureus was very high. They have excellent hydrophobic and antibacterial properties, mainly because the hydroxyl quaternary ammonium salt silicone oil contains hydroxyl groups, which can participate in the polyurethane polymerization chain extension reaction, thereby introducing hydrophobic silicone oil and multiple alkyl long carbon chains into the polyurethane molecular chain, which significantly improves the hydrophobic and water-repellent properties of the polyurethane finishing agent. In addition, the hydroxyl quaternary ammonium salt silicone oil contains organosilicon alkyl quaternary ammonium salt antibacterial groups, which are introduced into the polyurethane molecular chain, giving the finishing agent excellent antibacterial properties.

[0051] In Comparative Example 2, 1-bromooctadecane was not added during the quaternization reaction when preparing the hydroxyl-containing silicone oil. As a result, the hydroxyl-containing silicone oil and the polyurethane finishing agent prepared there did not contain quaternary ammonium salt groups, and the antibacterial rate of the finishing agent coating film was very low.

[0052] Comparative Example 3 involved reacting hexadecene with silicone oil, which lacked tertiary amine groups and could not undergo quaternization with 1-bromooctadecane. This resulted in the hydroxyl-containing silicone oil lacking quaternary ammonium salt groups, and the prepared alkyl silicone oil lacking hydroxyl groups. Consequently, it could not participate in the polymerization and chain extension reaction of polyurethane, and the hydrophobic silicone oil and alkyl long carbon chains could not be introduced into the polyurethane molecular chain. This resulted in a low water contact angle of the finishing agent, poor hydrophobic and water-repellent properties, and a very low antibacterial rate.

[0053] The N-methylallylaminohydroxypropyl alkane and 1-bromoethane in Comparative Example 4 do not contain long alkyl carbon chains. The hydroxy quaternary ammonium salt silicone oil and leather finishing agent prepared do not contain long alkyl carbon chains, resulting in a lower water contact angle and poorer hydrophobic and water-repellent properties of the finishing agent, and the antibacterial rate is significantly lower than that in Example 1.

[0054] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, and such modifications are protected by patent law as long as they fall within the scope of protection claimed in this application.

Claims

1. A preparation process for a fluorine-free water-repellent finishing agent for leather, characterized in that, The preparation process includes the following steps: Step S1: Add hydrogen-containing silicone oil and N-methylallylaminohydroxypropyl alkane to toluene, add chloroplatinic acid-isopropanol catalyst dropwise under nitrogen atmosphere, heat to 80-90℃, stir and react for 4-6 h, then add N,N-dimethylformamide solvent and bromoalkane monomer, heat to 90-110℃, stir and react for 36-48 h, distill under reduced pressure, wash, and dry to obtain hydroxyl quaternary ammonium salt silicone oil; Step S2: Mix the dried polyester polyol with the diisocyanate monomer and heat it to 70-80℃ in a nitrogen atmosphere for 2-3 hours. Then add 1,4-butanediol, hydroxyquaternary ammonium salt silicone oil, dibutyltin dilaurate, and ethyl acetate. React at 50-55℃ for 1-1.5 hours. Add water to dilute, stir, and remove ethyl acetate by vacuum distillation. Add emulsifier and nano silica, stir and disperse to obtain a fluorine-free water-repellent finishing agent for leather.

2. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 1, characterized in that, In step S1, the ratio of hydrogen-containing silicone oil, N-methylallylaminohydroxypropyl alkane, and bromoalkane monomer is 100g:(3-8.4)g:(2.2-6.2)g.

3. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 2, characterized in that, The bromoalkane monomer has the molecular formula Br-C. a H 2a+1 , where a is 10-18.

4. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 1, characterized in that, In step S2, the ratio of polyester polyol, diisocyanate monomer, 1,4-butanediol, hydroxy quaternary ammonium salt silicone oil, dibutyltin dilaurate, emulsifier, and nano silica is 100g:(23-29)g:(3-7)g:(8-20)g:(0.13-0.18)g:(3.6-5.2)g:(1.5-10)g.

5. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 4, characterized in that, The diisocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

6. The preparation process of the fluorine-free water-repellent finishing agent for leather according to claim 4, characterized in that, The preparation process of the N-methylallylaminohydroxypropyl alkane is as follows: alkyl glycidyl ether and N-methylallylamine are added to the reaction solvent, heated to 40-50℃, stirred for 4-7 hours, distilled under reduced pressure, and the product is separated by silica gel column chromatography to obtain N-methylallylaminohydroxypropyl alkane.

7. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 6, characterized in that, The reaction solvent is ethanol or isopropanol.

8. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 6, characterized in that, The ratio of the alkyl glycidyl ether to N-methylallylamine is (220-340) g: 100 g.

9. The preparation process of the fluorine-free leather water-repellent finishing agent according to claim 6, characterized in that, The structural formula of the alkyl glycidyl ether is as follows: n is 10-18.

Images