Antibacterial easy-to-clean composite leather with multi-level micro-nano structure and preparation method and application thereof

Abstract

The present application belongs to the technical field of composite leather, and discloses a multi-level micro-nano structure antibacterial easy-to-clean composite leather as well as a preparation method and application thereof. The present application uses fluorine-containing monomers, quaternary ammonium salt polymers and low-Tg polymers as mixed monomers, uses isocyanate as a condensing agent to perform a polymerization reaction, then adds glycerol and / or trimethylamine, further adds triethylenediamine, injects into a flat plate mold to self-assemble a micro-phase separation structure, and then performs solidification by increasing temperature to obtain the multi-level micro-nano structure antibacterial easy-to-clean composite leather. The present application uses the micro-phase separation effect of block polymers to construct functional domains with certain periodic continuity, i.e. micro separation and macro continuity, realizes the integration of multiple functions such as easy-to-clean and antibacterial of the composite leather, and effectively solves the problem of difficulty in mutual fusion of different functional molecules.

Description

Technical Field

[0001] This invention relates to the field of composite leather technology, and in particular to a multi-layered micro-nano structured antibacterial and easy-to-clean composite leather, its preparation method, and its application. Background Technology

[0002] Leather materials are widely used in automotive interiors and instrument decorations due to their excellent flexibility, skin-friendliness and aesthetics. Composite leather with multifunctional properties can be applied in many scenarios. Properties such as antibacterial properties, easy cleaning, flame retardancy, skin-friendliness, high stability and green non-toxicity are gradually becoming characteristics of new materials.

[0003] However, the functional properties of synthetic polymer materials are limited by their simple composition and physical structure, making it difficult to achieve multifunctionality. Current multi-material stacking techniques have achieved functional complexity, but the adhesion and continuity between different materials limit the stability of use and the service life of leather. For example, current automotive interior leather materials are still susceptible to bacterial contamination and difficult to clean; water is difficult to clean, and organic solvents (such as alcohol) damage the appearance. Therefore, developing materials to meet different application scenarios and expanding the multifunctionality of leather is of significant practical importance.

[0004] Superhydrophobicity and low surface energy are key properties of easy-to-clean materials, significantly reducing adhesion to contaminants. The antibacterial properties of materials are often related to their electrical charge; positively charged polymers can interfere with bacterial membranes, thus killing bacteria. A low glass transition temperature is essential for leather materials to maintain good flexibility. However, achieving the organic integration of materials with different properties is a major scientific challenge in the preparation of multifunctional composite leather. Existing technologies struggle to improve the effective compatibility between different materials, and macroscopic phase separation easily occurs, leading to non-uniformity in material properties and functions. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-layered micro-nano structured antibacterial and easy-to-clean composite leather, its preparation method, and its application, thereby solving the aforementioned problems existing in the prior art.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather, comprising the following steps: Using fluorine-containing monomers, quaternary ammonium salt polymers, and low Tg polymers as mixed monomers, and isocyanate as a condensing agent, the mixed monomers, condensing agent, and organic solvent are mixed, and triethylenediamine is added to carry out a polymerization reaction to obtain a prepolymer solution. Glycerol and / or glycerolamine are added to the prepolymer solution, followed by triethylenediamine, and then injected into a flat mold. The organic solvent is evaporated by heating to obtain a microphase separation structure. The microphase separation structure is then heated and cured to obtain the multi-layered micro-nano structured antibacterial and easy-to-clean composite leather. The fluorinated monomers, quaternary ammonium salts, and low-Tg polymers all have hydroxyl groups at both ends of their molecular chains.

[0007] Preferably, the fluorinated monomer is octafluoro-1,6-hexanediol and / or 1H,1H,12H,12H-perfluoro-1,12-dodecanediol.

[0008] Preferably, the quaternary ammonium salt polymer is one or more of the following: polyacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, and polyacrylamide ethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain; the number average molecular weight of the quaternary ammonium salt polymer is 500~5000g / mol.

[0009] Preferably, the low Tg polymer is one or more of polydimethylsiloxane with hydroxyl groups at both ends of the molecular chain, polybutadiene with hydroxyl groups at both ends of the molecular chain, and n-butyl polyacrylate with hydroxyl groups at both ends of the molecular chain; the number average molecular weight of the low Tg polymer is 500~5000 g / mol.

[0010] Preferably, the molar ratio of the fluorinated monomer, the quaternary ammonium salt polymer, and the low Tg polymer is 1:1:1; and the molar ratio of the isocyanate and the mixed monomer is 1~2:1.

[0011] Preferably, the isocyanate is one or more of isophorone diisocyanate, 4,4'-methylenebis(phenyl isocyanate), hexamethylene diisocyanate, and toluene diisocyanate.

[0012] Preferably, the polymerization reaction temperature is 50~150℃; the polymerization reaction time is 0.5~24h.

[0013] Preferably, the temperature for heating and evaporating the organic solvent is 50°C; the curing temperature is 50~150°C; and the curing time is 12~48h.

[0014] The present invention also provides a multi-level micro-nano structured antibacterial and easy-to-clean composite leather prepared by the above preparation method.

[0015] This invention also provides the application of multi-level micro-nano structured antibacterial and easy-to-clean composite leather in automotive interiors, medical devices, or furniture decorations.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: Fluorine-containing molecules possess superhydrophobicity and low surface energy, significantly reducing adhesion to contaminants. However, their outstanding stability makes processing and molding difficult, resulting in poor abrasion resistance, low flexibility, and difficulty in preparing usable leather materials. Furthermore, positively charged polymers can self-interfere with bacterial membranes to achieve antibacterial effects. However, simply mixing different functional polymers fails to achieve molecular-level fusion due to large intermolecular interactions, making it difficult to prepare homogeneous multifunctional composite leather. This invention uses monomers with different functions, first obtaining block polymer precursors through condensation polymerization, then utilizing the self-assembly behavior of each block molecule to form a microphase structure, achieving a multi-level micro / nano structure. Finally, the multi-level micro / nano structure is cross-linked and cured to prepare leather. The multi-level micro / nano structure composite leather material obtained by this invention utilizes the microphase separation effect of block polymers to construct functional domains with a certain periodic continuity—i.e., microscopic separation and macroscopic continuity—achieving the integration of multiple functions such as easy cleaning and antibacterial properties in composite leather, effectively solving the problem of the difficulty in fusing different functional molecules. The composite leather provided by this invention has multiple properties such as antibacterial, easy to clean, good biocompatibility, corrosion resistance, and flame retardancy, and has broad application prospects in the fields of automotive interiors, medical devices, and furniture decoration. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 This is a schematic diagram of the spherical microphase separation structure of the composite leather in Example 1; Figure 2 Example 1 describes the synthesis method of polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of its molecular chain; Figure 3 This is a transmission electron microscope image of the composite leather in Example 1; Figure 4 The mechanical property curves of the composite leather in Example 1 are shown. Figure 5 The image shows a test result of the antibacterial properties of the composite leather in Example 1. Figure 6 This is a cell compatibility test diagram of the composite leather in Example 1; Figure 7 This is the method for synthesizing polyacrylamide ethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, as described in Example 3. Detailed Implementation

[0019] This invention provides a method for preparing multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather, comprising the following steps: Using fluorine-containing monomers, quaternary ammonium salt polymers, and low Tg polymers as mixed monomers, and isocyanate as a condensing agent, the mixed monomers, condensing agent, and organic solvent are mixed, and triethylenediamine is added to carry out a polymerization reaction to obtain a prepolymer solution. Glycerol and / or glycerolamine are added to the prepolymer solution, followed by triethylenediamine, and then injected into a flat mold. The organic solvent is evaporated by heating to obtain a microphase separation structure. The microphase separation structure is then heated and cured to obtain the multi-layered micro-nano structured antibacterial and easy-to-clean composite leather. The fluorinated monomers, quaternary ammonium salts, and low-Tg polymers all have hydroxyl groups at both ends of their molecular chains.

[0020] In this invention, the fluorinated monomer is preferably octafluoro-1,6-hexanediol and / or 1H,1H,12H,12H-perfluoro-1,12-dodecanediol, more preferably octafluoro-1,6-hexanediol or 1H,1H,12H,12H-perfluoro-1,12-dodecanediol, and even more preferably octafluoro-1,6-hexanediol.

[0021] In this invention, the quaternary ammonium salt polymer is preferably one or more of the following: polyacryloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, polymethacryloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, and polyacrylamidoethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain. More preferably, it is polyacryloxyethyltrimethylammonium chloride or polymethacryloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain. More preferably, it is polymethacryloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain. The number average molecular weight of the quaternary ammonium salt polymer is preferably 500~5000 g / mol, more preferably 1000~3000 g / mol, and more preferably 1000 g / mol.

[0022] In this invention, the low-Tg polymer is preferably one or more of polydimethylsiloxane with hydroxyl groups at both ends of its molecular chain, polybutadiene with hydroxyl groups at both ends of its molecular chain, and n-butyl polyacrylate with hydroxyl groups at both ends of its molecular chain. More preferably, it is polydimethylsiloxane or polybutadiene with hydroxyl groups at both ends of its molecular chain, and even more preferably, it is polydimethylsiloxane with hydroxyl groups at both ends of its molecular chain. The number-average molecular weight of the low-Tg polymer is preferably 500-5000 g / mol, more preferably 1000-3000 g / mol, and even more preferably 2000 g / mol. The polydimethylsiloxane with hydroxyl groups at both ends of its molecular chain used in this embodiment is derived from hydroxyl-terminated polydimethylsiloxane (HO-PDMS-OH, Mn=2000) from Wuhan Yuancheng Chemical Co., Ltd., and the polybutadiene with hydroxyl groups at both ends of its molecular chain is derived from POLYVEST. ® HT (POLYVEST) ® EP HT) Hydroxyl-terminated liquid polybutadiene.

[0023] In this invention, the molar ratio of the fluorinated monomer, the quaternary ammonium salt polymer, and the low Tg polymer is preferably 1:1:1; the molar ratio of the isocyanate and the mixed monomer is preferably 1~2:1, more preferably 1.2~1.8:1, and even more preferably 1.5:1.

[0024] In this invention, the isocyanate is preferably one or more of isophorone diisocyanate, 4,4'-methylenebis(phenyl isocyanate), hexamethylene diisocyanate, and toluene diisocyanate, more preferably one of isophorone diisocyanate, 4,4'-methylenebis(phenyl isocyanate), and hexamethylene diisocyanate, and even more preferably isophorone diisocyanate.

[0025] In this invention, the organic solvent is preferably tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, or dimethylacetamide, more preferably tetrahydrofuran or dimethyl sulfoxide, and even more preferably tetrahydrofuran.

[0026] In this invention, in the reaction system obtained by adding the mixed monomers, condensing agents, and organic solvents to triethylenediamine, the total mass fraction of the mixed monomers and condensing agents is preferably 1-20 wt%, more preferably 5-15 wt%, and even more preferably 10 wt%, and the mass fraction of triethylenediamine is preferably 0.01-1 wt%, more preferably 0.1-0.8 wt%, and even more preferably 0.5 wt%.

[0027] In this invention, the temperature of the polymerization reaction is preferably 50~150℃, more preferably 80~120℃, and even more preferably 90℃; the time of the polymerization reaction is preferably 0.5~24h, more preferably 6~20h, and even more preferably 12h.

[0028] In this invention, the molar ratio of glycerol and / or glycerin and isocyanate is preferably 1:0.1~1, more preferably 1:0.5~1, and even more preferably 1:1.

[0029] In this invention, in the reaction system obtained by adding glycerol and / or glycerol and triethylenediamine to the prepolymer solution, the mass fraction of triethylenediamine is preferably 0.01~1wt%, more preferably 0.1~0.8wt%, and more preferably 0.5wt%.

[0030] In this invention, the temperature for heating and evaporating the organic solvent is preferably 50°C; the curing temperature is preferably 50~150°C, more preferably 60~100°C, and even more preferably 90°C; the curing time is preferably 12~48h, more preferably 16~32h, and even more preferably 24h.

[0031] The present invention also provides a multi-level micro-nano structured antibacterial and easy-to-clean composite leather prepared by the above preparation method.

[0032] This invention also provides the application of multi-level micro-nano structured antibacterial and easy-to-clean composite leather in automotive interiors, medical devices, or furniture decorations.

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] (1) Using commercially available octafluoro-1,6-hexanediol, polymethacryloyloxyethyltrimethylammonium chloride (molecular weight 1000 g / mol) with hydroxyl groups at both ends of the molecular chain and polydimethylsiloxane (HO-PDMS-OH, molecular weight 2000 g / mol) with hydroxyl groups at both ends of the molecular chain as raw materials, the molar ratio is 1:1:1; the raw materials are dissolved in tetrahydrofuran, and the mass fraction of the raw materials in the system is 10wt%; then isophorone diisocyanate is added, and the molar ratio of isocyanate to the total raw materials is 1.5:1; then triethylenediamine is added, and the mass fraction of triethylenediamine in the system is 0.5wt%. The mixture is polymerized at 90℃ for 12h to obtain a prepolymer solution; (2) Add glycerol to the prepolymer solution, with a molar ratio of glycerol to isocyanate of 1:1; then add triethylenediamine, with a mass fraction of 0.5wt% in the system; inject the mixture into a flat mold, heat to 50°C to volatilize tetrahydrofuran, and the block polymer self-assembles to obtain a spherical phase microphase separation structure. (3) The system temperature is raised to 90℃ and cross-linked and cured for 24 hours to obtain composite leather.

[0036] A schematic diagram of the spherical microphase separation structure of the composite leather prepared in this embodiment is shown below. Figure 1 As shown.

[0037] The synthesis method of polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain used in this embodiment is as follows: The synthesis route is as follows... Figure 2 As shown, specifically, methacryloyloxyethyltrimethylammonium chloride monomer was polymerized using PMHD reagent containing hydroxyl groups at both ends. The reagents were: PMHD (10 mmol), methacryloyloxyethyltrimethylammonium chloride (20 mol), DMF as solvent, monomer concentration of 60% v / v, and AIBN as initiator at 20 mmol. Polymerization was carried out at 70°C for 5 h to obtain polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends. After permeation with 500 g / mol dialysis tape for 48 h, the polymer was obtained by freeze-drying. The PMHD molecule was obtained according to the reported method (Colloid. Polym. Sci. (2014) 292:2633-2645).

[0038] Performance testing: Transmission electron microscopy was used to reveal the microphase separation morphology of the composite leather, and the results are as follows: Figure 3 As shown, the composite leather prepared in this embodiment has a spherical multi-level micro-nano structure.

[0039] The mechanical properties of the composite leather were tested using a universal testing machine at room temperature and a tensile speed of 10 mm / min. The results are as follows: Figure 4 As shown.

[0040] The antibacterial performance test method is as follows: In a 6-well plate, the composite leather fragments of Example 1 are dispersed at the bottom of the plate, and then Escherichia coli bacterial suspension (500 μL, 1× 10⁻⁶) is added. 6 (CFU / mL), incubated at 37℃ for 12, 24, 36, and 48 hours. The antibacterial effect was assessed using the plate count method. Results are as follows: Figure 5 As shown in the figure. The results indicate that it has significant antibacterial effects (>99%) against Escherichia coli and Staphylococcus aureus.

[0041] The biocompatibility test method was as follows: Composite leather scraps were co-incubated with PBS for 24 hours to obtain an extract of the leather material. The extract was then diluted to 10%, 30%, 50%, 70%, and 100% concentrations. L929 cell line was used as the test cells. 10,000 cells were added to a 96-well plate and incubated for 12 hours. Then, 100 μL of different concentrations of extract were added and incubated for another 24 hours. Cell viability was then measured using a microplate reader. The results are as follows: Figure 6 As shown.

[0042] The composite leather prepared in this embodiment has an elongation at break >200%, a tensile strength >1MPa, and an elastic recovery rate >95%. It exhibits excellent antibacterial and easy-to-clean properties, with an antibacterial rate of >99.8% against Escherichia coli. It also demonstrates good biocompatibility, with a cell viability rate >98%.

[0043] Example 2

[0044] The preparation method of the composite leather is the same as that in Example 1, except that the octafluoro-1,6-hexanediol in Example 1 is replaced with 1H,1H,12H,12H-perfluoro-1,12-dodecanediol.

[0045] Example 3

[0046] The preparation method of the composite leather is the same as in Example 1, except that the polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain in Example 1 is replaced with polyacrylamide ethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain. The synthesis method of polyacrylamide ethyltrimethylammonium chloride is the same as that in Example 1, except that the monomer is replaced with acrylamide ethyltrimethylammonium chloride, and the synthesis route is as follows. Figure 7 As shown.

[0047] Example 4

[0048] The preparation method of the composite leather is the same as that in Example 1, except that the isophorone diisocyanate in Example 1 is replaced with hexamethylene diisocyanate.

[0049] Example 5

[0050] The preparation method of the composite leather is the same as that in Example 1, except that the tetrahydrofuran in Example 1 is replaced with dimethyl sulfoxide, and the mass fraction of the raw material in the system is 5 wt%.

[0051] Example 6

[0052] The preparation method of the composite leather is the same as in Example 1, except that the polydimethylsiloxane with hydroxyl groups at both ends of the molecular chain in Example 1 is replaced with polybutadiene (POLYVEST) with hydroxyl groups at both ends of the molecular chain. ® EP HT), with a molecular weight of 5000 g / mol.

[0053] Example 7

[0054] The preparation method of the composite leather is the same as in Example 1, except that the glycerol in Example 1 is replaced with glycerin.

[0055] Example 8

[0056] The preparation method of the composite leather is the same as that in Example 1, except that the molar ratio of isocyanate to total raw materials in Example 1 is 1.2:1.

[0057] Example 9

[0058] The preparation method of the composite leather is the same as that in Example 1, except that the molar ratio of glycerol to isocyanate in Example 1 is 1:0.5.

[0059] Example 10

[0060] The preparation method of the composite leather is the same as in Example 1, except that the polydimethylsiloxane with hydroxyl groups at both ends of the molecular chain in Example 1 is replaced with polybutyl acrylate with hydroxyl groups at both ends of the molecular chain, with a molecular weight of 3000 g / mol. The synthesis method of the polybutyl acrylate with hydroxyl groups at both ends of the molecular chain is the same as that of the polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain in Example 1, except that the monomer is replaced with polybutyl acrylate.

[0061] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather, characterized in that, Includes the following steps: Using fluorine-containing monomers, quaternary ammonium salt polymers, and low Tg polymers as mixed monomers, and isocyanate as a condensing agent, the mixed monomers, condensing agent, and organic solvent are mixed, and triethylenediamine is added to carry out a polymerization reaction to obtain a prepolymer solution. Glycerol and / or glycerolamine are added to the prepolymer solution, followed by triethylenediamine, and then injected into a flat mold. The organic solvent is evaporated by heating to obtain a microphase separation structure. The microphase separation structure is then heated and cured to obtain the multi-layered micro-nano structured antibacterial and easy-to-clean composite leather. The fluorinated monomers, quaternary ammonium salts, and low-Tg polymers all have hydroxyl groups at both ends of their molecular chains.

2. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 1, characterized in that, The fluorinated monomer is octafluoro-1,6-hexanediol and / or 1H,1H,12H,12H-perfluoro-1,12-dodecanediol.

3. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 2, characterized in that, The quaternary ammonium salt polymer is one or more of the following: polyacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, polymethacryloyloxyethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain, and polyacrylamide ethyltrimethylammonium chloride with hydroxyl groups at both ends of the molecular chain; the number average molecular weight of the quaternary ammonium salt polymer is 500~5000g / mol.

4. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 3, characterized in that, The low Tg polymer is one or more of the following: polydimethylsiloxane with hydroxyl groups at both ends of the molecular chain, polybutadiene with hydroxyl groups at both ends of the molecular chain, and n-butyl polyacrylate with hydroxyl groups at both ends of the molecular chain; the number average molecular weight of the low Tg polymer is 500~5000 g / mol.

5. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to any one of claims 1 to 4, characterized in that, The molar ratio of the fluorinated monomer, quaternary ammonium salt polymer, and low Tg polymer is 1:1:1; the molar ratio of the isocyanate and mixed monomer is 1~2:

1.

6. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 5, characterized in that, The isocyanate is one or more of isophorone diisocyanate, 4,4'-methylenebis(phenyl isocyanate), hexamethylene diisocyanate, and toluene diisocyanate.

7. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 6, characterized in that, The polymerization reaction is carried out at a temperature of 50~150℃ and for a duration of 0.5~24h.

8. The method for preparing a multi-layered micro / nano-structured antibacterial and easy-to-clean composite leather according to claim 7, characterized in that, The temperature for heating and evaporating the organic solvent is 50°C; the curing temperature is 50~150°C; and the curing time is 12~48h.

9. A multi-layered micro-nano structured antibacterial and easy-to-clean composite leather prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the multi-layered micro-nano structured antibacterial and easy-to-clean composite leather of claim 9 in automotive interiors, medical devices, or furniture decoration.

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