Renewable antibacterial waterborne polyurethane synthetic leather having high peel strength, and preparation method

Abstract

The present invention relates to the technical field of synthetic leathers. Disclosed are a renewable antibacterial waterborne polyurethane synthetic leather having high peel strength, and a preparation method. The present invention comprises: coating release paper with a renewable durable antibacterial waterborne polyurethane emulsion to obtain a polyurethane surface layer, and attaching the polyurethane surface layer to the surface of a surface-modified base cloth to obtain the base cloth containing a polyurethane layer; and carrying out chlorination to obtain the renewable antibacterial waterborne polyurethane synthetic leather having high peel strength. A halamine antibacterial monomer used by the present invention has antibacterial renewability, and an ultraviolet light absorber is introduced, so that the antibacterial durability of the polyurethane coating is improved. The peel strength between the polyurethane surface layer and the base cloth of the prepared synthetic leather is high, the bonding performance is improved by means of an epoxy resin, a micro rough structure is further constructed on the surface of the base cloth by means of surface modification, and by means of a mechanical engagement effect, the bonding strength between the polyurethane surface layer and the base cloth is increased.

Description

High peel strength renewable antibacterial waterborne polyurethane synthetic leather and preparation method thereof Technical Field

[0001] The invention relates to the technical field of synthetic leather, in particular to a high-peeling-strength renewable antibacterial waterborne polyurethane synthetic leather and a preparation method thereof. Background Art

[0002] Synthetic leather generally refers to simulated leather products made from non-woven fabrics, coated with polyurethane or polyvinyl chloride, and processed through film processing. Polyurethane synthetic leather, due to its excellent wear resistance, flexural strength, waterproof and breathable properties, and weather resistance, is widely used in footwear, furniture, clothing, luggage, and automotive interiors, becoming the best alternative to natural leather. However, these leather products come into close contact with the human body and easily absorb sweat and sebum containing metabolites from the skin, providing a nutrient source for bacterial growth. This bacterial growth not only produces unpleasant odors and reduces product performance (such as discoloration and reduced mechanical strength), but can also pose a threat to human health and life safety (such as causing skin diseases and inducing disease by entering the body).

[0003] Halamine antimicrobial agents refer to antimicrobial agents containing one or more NX structures (X is a halogen such as Cl, Br, etc.) in their molecular structure. They are a type of renewable antimicrobial agent prepared by reacting a compound containing an amine, amide or imide group with a hypohalite. The molecular structure of halamine compounds can introduce active groups such as double bonds (C=C) (such as ADMH, VBDMH, etc.), hydroxyl groups (-OH) (such as MDMH, etc.), and silanol groups (Si-OH) (such as DTH, etc.), which can improve the bonding strength between the antimicrobial agent and the matrix through valence bond bonding, thereby improving the antimicrobial durability of the grafted modified material. Halamine antimicrobial agents have become a research hotspot for antimicrobial materials due to their high efficiency, broad spectrum and non-mutagenicity. ZL202010796537.9 discloses a method for preparing antimicrobial polyurethane nanofibers. The specific method is to graft a hydrophilic polyacrylic acid polymer with a tetraalkylpiperidinol monomer and blend it with a hydrophobic polyurethane, and use electrospinning to make a nanofiber membrane with a certain interpenetrating network structure of affinity / disappointment polymers. Application No. 202310346920.8 and “Halamine Compound Modified Polyurethane Nanofiber Membrane Structure and Antibacterial Properties” (Printing and Dyeing, 2023, (7): 1-6) use 1-hydroxymethyl-5,5-dimethylhydantoin (MDMH) as a monomer, which is grafted into the structure during the polyurethane synthesis process and then made into a nanofiber membrane by electrospinning. Tetraalkylpiperidinol monomers and MDMH molecular structures contain only one hydroxyl group, which easily causes the linear polyurethane molecular chain to undergo end-capping and termination reactions, making the polyurethane molecular weight difficult to control and the molecular weight distribution relatively wide, thereby affecting the performance of the nanofiber membrane. Invention patent ZL202210809792.1 discloses a method for preparing polyurethane nanofiber materials for air purification. First, polycaprolactone and methylene diphenyl diisocyanate are prepolymerized, and then the two hydroxyl groups (-OH) in imidazolidinyl urea are used to participate in the polymerization reaction of polyurethane. Then, the imidazolidinyl urea modified polyurethane is mixed with ordinary polyurethane, and then antibacterial nanofibers are prepared by electrospinning. Although this method solves the effect of antibacterial monomers on the molecular weight of polyurethane, it is relatively expensive.

[0004] Data shows that although N-Cl halamines have excellent antimicrobial properties and are reproducible, the instability of the N-Cl bond under long-wave ultraviolet light (315-400nm) causes a rapid decrease in the active chlorine content in a short period of time, resulting in a rapid decrease in the antimicrobial properties of the material. While there have been numerous reports on the use of halamine-structured compounds to impart durable and reproducible antimicrobial properties to polyurethanes, there have been no reports on how to improve the light resistance of N-Cl halamine-modified waterborne polyurethanes.

[0005] Waterborne polyurethane is a new type of polyurethane system that uses water instead of organic solvents as a dispersion medium. Compared with solvent-based polyurethane, although waterborne polyurethane has the advantage of being green and environmentally friendly, its bonding strength with the leather base fabric is lower, which leads to easy peeling between the surface layer and the base fabric in synthetic leather. At present, there are two main common methods to improve peel strength. One is to apply a layer of adhesive between the surface layer and the base fabric (application number: 202210204113.8), and the other is to introduce epoxy resin into the polyurethane structure. Although these two common methods are relatively effective, they only consider the effects of the surface resin and adhesive, and do not consider the fiber structure of the base fabric itself, resulting in limited improvement.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to provide a high peel strength renewable antibacterial water-based polyurethane synthetic leather and a preparation method, so as to solve the problems of low bonding strength between synthetic leather base fabric and polyurethane emulsion prepared by the prior art, easy peeling and poor antibacterial performance of polyurethane emulsion.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a method for preparing a high-peel strength renewable antibacterial waterborne polyurethane synthetic leather, comprising the following steps:

[0010] The base fabric is immersed in a surface modification liquid to form a surface modification layer on the surface of the base fabric to obtain a pretreated base fabric;

[0011] The renewable long-lasting antibacterial water-based polyurethane emulsion is coated on the release paper and dried to obtain a polyurethane surface layer; the pretreated base fabric is laminated on the polyurethane surface layer and dried, and then the release paper is peeled off to obtain a base fabric containing a polyurethane layer;

[0012] The base fabric containing the polyurethane layer is subjected to chlorination treatment to obtain a high peel strength renewable antibacterial waterborne polyurethane synthetic leather;

[0013] The preparation method of the renewable long-lasting antibacterial aqueous polyurethane emulsion comprises the following steps:

[0014] (1) mixing a polymer diol and a diisocyanate to react to obtain a mixture a;

[0015] (2) mixing mixture a, dibutyltin dilaurate, and N,N-dimethylformamide to react to obtain mixture b;

[0016] (3) mixing the mixture b, the chain extender, the epoxy resin, and N,N-dimethylformamide to react to obtain a mixture c;

[0017] (4) mixing the mixture c, the halamine antibacterial monomer, the ultraviolet absorber, and N,N-dimethylformamide to react to obtain a mixture d;

[0018] (5) Mixing mixture d, an antioxidant, triethylamine, and N,N-dimethylformamide for neutralization reaction to obtain mixture e;

[0019] (6) adjusting the viscosity of the mixture e with N,N-dimethylformamide, and then emulsifying the mixture with water and diethylenetriamine to obtain a renewable long-lasting antibacterial water-based polyurethane emulsion;

[0020] The halamine antibacterial monomer in step (4) is 3-(2,3-dihydroxypropyl)-5,5-dimethylhydantoin, and its structural formula is shown below:

[0021] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial water-based polyurethane synthetic leather, the base fabric is one of polyester filament knitted fabric, polyester filament woven fabric, polyester staple fiber knitted fabric, polyester staple fiber woven fabric, polyester staple fiber spunlace non-woven fabric, and polyester staple fiber needle-punched non-woven fabric.

[0022] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, the composition of the surface modification liquid includes: 10-15 mL / L of benzyl alcohol, 0.3-0.5 g / L of accelerator, and 15-20 g / L of sodium hydroxide;

[0023] The bath ratio of the immersion is 1:5-10; the immersion temperature is 100-120° C.; and the immersion time is 20-30 minutes.

[0024] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, the coating amount of the renewable long-lasting antibacterial waterborne polyurethane emulsion applied to the release paper is 150 to 200 g / m 2 .

[0025] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial water-based polyurethane synthetic leather, the chlorination treatment is immersion in a sodium hypochlorite solution; the effective chlorine content of the sodium hypochlorite solution is 3000 ppm; the bath ratio of the immersion is 1:5-10; and the immersion time is 20-30 min.

[0026] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, in the method for preparing the renewable long-lasting antibacterial waterborne polyurethane emulsion, the mass ratio of the polymer diol to the diisocyanate in step (1) is 30-40:15-20;

[0027] The reaction temperature of step (1) is 60-65° C.; the reaction time of step (1) is 60-90 min;

[0028] The mass volume ratio of the polymer diol in step (1) to the dibutyltin dilaurate and N,N-dimethylformamide in step (2) is 30-40 g:0.1-0.3 g:10-20 mL;

[0029] The reaction temperature of step (2) is 70-75° C.; the reaction time of step (2) is 90-120 min;

[0030] The mass volume ratio of the polymer diol in step (1) to the chain extender, epoxy resin, and N,N-dimethylformamide in step (3) is 30-40 g: 3-5 g: 5-8 g: 15-20 mL;

[0031] The reaction temperature of step (3) is 80-90° C.; the reaction time of step (3) is 30-45 min.

[0032] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial water-based polyurethane synthetic leather, in the method for preparing the renewable long-lasting antibacterial water-based polyurethane emulsion, the ultraviolet absorber in step (4) is 2,4-dihydroxybenzophenone;

[0033] The mass volume ratio of the polymer diol in step (1) to the halamine antibacterial monomer, ultraviolet absorber, and N,N-dimethylformamide in step (4) is 30-40 g: 1-3 g: 2-5 g: 15-25 mL;

[0034] The reaction temperature of step (4) is 80-90° C.; the reaction time of step (4) is 60-90 min.

[0035] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial water-based polyurethane synthetic leather, in the method for preparing the renewable long-lasting antibacterial water-based polyurethane emulsion, the mass volume ratio of the polymer diol in step (1) to the antioxidant, triethylamine, and N,N-dimethylformamide in step (5) is 30-40 g: 0.01-0.1 g: 3-5 g: 5-15 mL;

[0036] The temperature of the neutralization reaction in step (5) is 50 to 60° C.; the time of the neutralization reaction in step (5) is 30 to 60 minutes.

[0037] Preferably, in the above-mentioned method for preparing a high peel strength renewable antibacterial water-based polyurethane synthetic leather, in the method for preparing the renewable long-lasting antibacterial water-based polyurethane emulsion, the viscosity in step (6) is 7000-8000 Pa / s;

[0038] The mass volume ratio of the polymer diol in step (1) to the water and diethylenetriamine in step (6) is 30-40 g: 200-300 mL: 0.5-1 mL;

[0039] The emulsification temperature in step (6) is 25 to 30° C.; the emulsification time in step (6) is 60 to 90 minutes.

[0040] The invention also provides a method for preparing a high-peeling-strength renewable antibacterial water-based polyurethane synthetic leather, which produces a high-peeling-strength renewable antibacterial water-based polyurethane synthetic leather.

[0041] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The preparation conditions of the renewable long-lasting antibacterial water-based polyurethane emulsion of the present invention are controllable. The polymer diol, diisocyanate, halogenamine antibacterial monomer and ultraviolet absorber are polymerized in one step. The reaction steps are simple and the reaction is basically carried out under medium and low temperature conditions below 100°C.

[0043] (2) The film formed by coating the aqueous polyurethane emulsion of the present invention has long-lasting antibacterial properties. The halamine antibacterial monomer structure used does not contain α-hydrogen, and a UV absorber is simultaneously incorporated into the polyurethane structure, thereby reducing the effect of ultraviolet rays in sunlight on the stability of the N-Cl bond, thereby increasing the stability of the N-Cl bond and improving the antibacterial durability of the polyurethane coating. Furthermore, the antibacterial properties are reproducible, and the halamine antibacterial monomer structure can achieve reproducible antibacterial properties through repeated dehalogenation and halogenation.

[0044] (3) The peel strength between the polyurethane surface layer and the base fabric in the synthetic leather of the present invention is high. First, the bonding performance of the polyurethane is improved by copolymerizing the epoxy resin. Second, a microscopic rough structure is constructed on the surface of the base fabric by alkali reduction surface modification of the base fabric. The mechanical meshing effect of the microscopic rough structure and the polyurethane is then utilized to further improve the bonding strength between the polyurethane surface layer and the base fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0046] FIG1 is a SEM image of the surface-modified base fabric fiber in step (1) of Example 1;

[0047] FIG2 is an SEM image of the base fabric fiber without surface modification in Comparative Example 1;

[0048] Figure 3 is a schematic diagram of the dehalogenation and halogenation process of halamine antibacterial monomers. DETAILED DESCRIPTION

[0049] The present invention provides a method for preparing a high-peel strength renewable antibacterial waterborne polyurethane synthetic leather, comprising the following steps:

[0050] The base fabric is immersed in a surface modification liquid to form a surface modification layer on the surface of the base fabric to obtain a pretreated base fabric;

[0051] The renewable long-lasting antibacterial water-based polyurethane emulsion is coated on the release paper and dried to obtain a polyurethane surface layer; the pretreated base fabric is laminated on the polyurethane surface layer and dried, and then the release paper is peeled off to obtain a base fabric containing a polyurethane layer;

[0052] The base fabric containing the polyurethane layer is subjected to chlorination treatment to obtain a high peel strength renewable antibacterial waterborne polyurethane synthetic leather.

[0053] In the present invention, the base fabric is preferably one of polyester filament knitted fabric, polyester filament woven fabric, polyester staple fiber knitted fabric, polyester staple fiber woven fabric, polyester staple fiber spunlace nonwoven fabric, and polyester staple fiber needle-punched nonwoven fabric, further preferably one of polyester filament woven fabric, polyester staple fiber woven fabric, and polyester staple fiber spunlace nonwoven fabric, and more preferably polyester staple fiber woven fabric.

[0054] In the present invention, the composition of the surface modification liquid includes: benzyl alcohol is preferably 10-15 mL / L, more preferably 11-14 mL / L, more preferably 12 mL / L; the accelerator is preferably 0.3-0.5 g / L, more preferably 0.35-0.45 g / L, more preferably 0.4 g / L; sodium hydroxide is preferably 15-20 g / L, more preferably 17-19 g / L, more preferably 18 g / L.

[0055] In the present invention, the accelerator is preferably one of dodecyldimethylbenzylammonium chloride, hexadecyltrimethylammonium bromide, and octadecyldimethylhydroxyethylammonium nitrate, more preferably dodecyldimethylbenzylammonium chloride or hexadecyltrimethylammonium bromide, and more preferably dodecyldimethylbenzylammonium chloride.

[0056] In the present invention, the bath ratio of the immersion is preferably 1:5-10, more preferably 1:6-10, and more preferably 1:10; the immersion temperature is preferably 100-120°C, more preferably 105-115°C, and more preferably 110°C; the immersion time is preferably 20-30 min, more preferably 25-30 min, and more preferably 30 min.

[0057] In the present invention, the coating amount of the renewable long-lasting antibacterial water-based polyurethane emulsion applied to the release paper is preferably 150 to 200 g / m2 , more preferably 160 to 180 g / m 2 , more preferably 170g / m 2 .

[0058] In the present invention, the renewable long-lasting antibacterial aqueous polyurethane emulsion is coated on the release paper and then dried, preferably at 110° C. for 5 minutes.

[0059] In the present invention, the lamination speed is preferably 7 m / min.

[0060] In the present invention, the pretreated base fabric is laminated onto the polyurethane surface layer and then dried, preferably at 130° C. for 3 minutes.

[0061] In the present invention, the chlorination treatment is preferably performed by immersing in a sodium hypochlorite solution; the available chlorine content of the sodium hypochlorite solution is preferably 3000 ppm; the bath ratio of the immersion is preferably 1:5-10, more preferably 1:5-7, and more preferably 1:5; the immersion time is preferably 20-30 min, more preferably 22-30 min, and more preferably 30 min.

[0062] The present invention also provides a method for preparing the renewable long-lasting antibacterial aqueous polyurethane emulsion, comprising the following steps:

[0063] (1) mixing a polymer diol and a diisocyanate to react to obtain a mixture a;

[0064] (2) Mixing mixture a, dibutyltin dilaurate, and N,N-dimethylformamide to react to obtain mixture b;

[0065] (3) mixing the mixture b, the chain extender, the epoxy resin, and N,N-dimethylformamide to react to obtain a mixture c;

[0066] (4) mixing the mixture c, the halamine antibacterial monomer, the ultraviolet absorber, and N,N-dimethylformamide to react to obtain a mixture d;

[0067] (5) Mixing mixture d, an antioxidant, triethylamine, and N,N-dimethylformamide for neutralization reaction to obtain mixture e;

[0068] (6) The viscosity of the mixture e was adjusted using N,N-dimethylformamide, and then the mixture was mixed with water and diethylenetriamine for emulsification to obtain a renewable long-lasting antibacterial water-based polyurethane emulsion.

[0069] In the present invention, the polymer diol in step (1) further includes a dehydration treatment before use; the temperature of the dehydration treatment is preferably 80° C.; and the time of the dehydration treatment is preferably 2 hours.

[0070] In the present invention, the polymer diol in step (1) is preferably a mixture of polycaprolactone polyol (PLG) and polyester diol (PBA2000) in a mass ratio of 1:2.

[0071] In the present invention, the diisocyanate in step (1) is preferably a mixture of isophorone diisocyanate (IPDI) and dicyclohexylmethane diisocyanate (HMDI) in a mass ratio of 3:1.

[0072] In the present invention, the mass ratio of the polymer diol to the diisocyanate in step (1) is preferably 30-40:15-20, more preferably 30-35:17-20, and even more preferably 30:20.

[0073] In the present invention, the reaction temperature of step (1) is preferably 60-65°C, more preferably 63-65°C, and more preferably 65°C; the reaction time of step (1) is preferably 60-90 min, more preferably 70-90 min, and more preferably 80 min.

[0074] In the present invention, the mass volume ratio of the polymer diol in step (1) to the dibutyltin dilaurate and N,N-dimethylformamide in step (2) is preferably 30-40 g:0.1-0.3 g:10-20 mL, more preferably 30-35 g:0.1-0.2 g:12-18 mL, and more preferably 30 g:0.1 g:15 mL.

[0075] In the present invention, the reaction temperature in step (2) is preferably 70-75°C, more preferably 70-73°C, and more preferably 70°C; the reaction time in step (2) is preferably 90-120 min, more preferably 100-115 min, and more preferably 110 min.

[0076] In the present invention, the mixing in step (2) is preferably as follows: at the reaction temperature of step (1), dibutyltin dilaurate and mixture a are preliminarily mixed, and then during the process of heating from the reaction temperature of step (1) to the reaction temperature of step (2), N,N-dimethylformamide is added to the mixed system consisting of mixture a and dibutyltin dilaurate in equal amounts in 2 to 5 times to complete the mixing.

[0077] In the present invention, the mass volume ratio of the polymer diol in step (1) to the chain extender, epoxy resin and N,N-dimethylformamide in step (3) is preferably 30-40 g:3-5 g:5-8 g:15-20 mL, more preferably 30-35 g:3.2-4.5 g:6-8 g:18-20 mL, and more preferably 30 g:4 g:8 g:20 mL.

[0078] In the present invention, the reaction temperature in step (3) is preferably 80-90°C, more preferably 80-86°C, and more preferably 85°C; the reaction time in step (3) is preferably 30-45 min, more preferably 40-45 min, and more preferably 45 min.

[0079] In the present invention, the chain extender in step (3) is preferably 1,4-butanediol (BDO).

[0080] In the present invention, the epoxy resin in step (3) is preferably epoxy resin E51.

[0081] In the present invention, the halamine antibacterial monomer in step (4) is preferably 3-(2,3-dihydroxypropyl)-5,5-dimethylhydantoin, and its structural formula is shown below:

[0082] In the present invention, a preparation method of 3-(2,3-dihydroxypropyl)-5,5-dimethylhydantoin comprises the following steps: dissolving 0.01 mol of 5,5-dimethylhydantoin in 50 mL of deionized water, stirring evenly, adding 0.02 mol of NaOH, and placing the mixture in a 250 mL flat-bottom flask for standby use after the mixture is completely dissolved; dissolving 0.01 mol of 3-chloroglycerol in 50 mL of deionized water, and slowly adding the mixture dropwise to the 5,5-dimethylhydantoin solution for the next step of reaction, and fully reacting at room temperature for 12 hours under magnetic stirring; after the reaction is completed, adjusting the pH of the reaction solution to 6.0 with dilute sulfuric acid; then removing moisture from the reaction solution with a rotary evaporator, and dissolving the obtained solid in DMF to filter out the reaction by-product NaCl; and then removing DMF from the filtrate by distillation under reduced pressure to obtain 3-(2,3-dihydroxypropyl)-5,5-dimethylhydantoin.

[0083] In the present invention, the ultraviolet absorber in step (4) is preferably 2,4-dihydroxybenzophenone.

[0084] In the present invention, the mass volume ratio of the polymer diol in step (1) to the halamine antibacterial monomer, ultraviolet absorber, and N,N-dimethylformamide in step (4) is preferably 30-40 g:1-3 g:2-5 g:15-25 mL, more preferably 30-35 g:1-2 g:3-5 g:18-23 mL, and more preferably 30 g:2 g:4 g:20 mL.

[0085] In the present invention, the reaction temperature in step (4) is preferably 80-90°C, more preferably 80-85°C, and more preferably 80°C; the reaction time in step (4) is preferably 60-90 min, more preferably 70-90 min, and more preferably 90 min.

[0086] In the present invention, the mass volume ratio of the polymer diol in step (1) to the antioxidant, triethylamine, and N,N-dimethylformamide in step (5) is preferably 30-40 g:0.01-0.1 g:3-5 g:5-15 mL, more preferably 30-35 g:0.04-0.07 g:4-5 g:10-15 mL, and more preferably 30 g:0.06 g:4 g:10 mL.

[0087] In the present invention, the temperature of the neutralization reaction in step (5) is preferably 50-60°C, more preferably 52-56°C, and more preferably 55°C; the time of the neutralization reaction in step (5) is preferably 30-60 min, more preferably 40-60 min, and more preferably 50 min.

[0088] In the present invention, the antioxidant in step (5) is preferably antioxidant 1010.

[0089] In the present invention, the viscosity in step (6) is preferably 7000-8000 Pa / s, more preferably 7000-7500 Pa / s, and even more preferably 7000 Pa / s.

[0090] In the present invention, the mass volume ratio of the polymer diol in step (1) to the water and diethylenetriamine in step (6) is preferably 30-40 g:200-300 mL:0.5-1 mL, more preferably 30-35 g:200-250 mL:0.6-0.9 mL, and more preferably 30 g:200 mL:0.8 mL.

[0091] In the present invention, the emulsification temperature in step (6) is preferably 25-30°C, more preferably 25-28°C, and more preferably 27°C; the emulsification time in step (6) is preferably 60-90 min, more preferably 80-90 min, and more preferably 90 min.

[0092] In the present invention, the mixing in step (6) is preferably as follows: firstly, the first portion of water is added under stirring, and after the phase inversion is successful, the remaining water is quickly added, and then diethylenetriamine is added for emulsification.

[0093] In the present invention, the stirring speed is preferably 1500 rpm.

[0094] In the present invention, the temperature of the water in step (6) is preferably 5°C.

[0095] The invention also provides a method for preparing a high-peeling-strength renewable antibacterial water-based polyurethane synthetic leather, which produces a high-peeling-strength renewable antibacterial water-based polyurethane synthetic leather.

[0096] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0097] Example 1

[0098] This embodiment provides a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, the preparation method of which includes the following steps:

[0099] (1) Immersing a base fabric (polyester filament knitted fabric) in a surface modification solution at a bath ratio of 1:5 at 110°C for 30 minutes to form a surface modification layer on the surface of the base fabric, thereby obtaining a pretreated base fabric; wherein the surface modification solution comprises: 10 mL / L benzyl alcohol, 0.5 g / L hexadecyltrimethylammonium bromide, and 15 g / L sodium hydroxide;

[0100] (2) Apply the renewable long-lasting antibacterial water-based polyurethane emulsion on the release paper at a coating amount of 200 g / m 2 , drying in an oven at a temperature of 110°C for 5 minutes to obtain a polyurethane surface layer, laminating the polyurethane surface layer to the surface of the pretreated base fabric at a speed of 7 m / min, drying in an oven at a temperature of 130°C for 3 minutes, and then removing the release paper to obtain a base fabric containing a polyurethane layer;

[0101] (3) The base fabric containing the polyurethane layer was immersed in a sodium hypochlorite solution with an effective chlorine content of 3000 ppm at a bath ratio of 1:5 for 30 minutes to obtain a high peel strength renewable antibacterial water-based polyurethane synthetic leather.

[0102] The preparation method of the renewable long-lasting antibacterial aqueous polyurethane emulsion described in step (2) above comprises the following steps:

[0103] 30 g of polymer diol (a mixture of PLG and PBA2000 in a mass ratio of 1:2) was added to the reaction equipment, heated to 80°C under vacuum conditions, dehydrated for 2 hours, cooled to 50°C, and then 20 g of diisocyanate (a mixture of IPDI and HMDI in a mass ratio of 3:1) was added, heated to 60°C, and reacted at constant temperature for 60 minutes to obtain mixture a; 0.1 g of dibutyltin dilaurate was added to mixture a, and the temperature was raised to 70°C. During the heating process, a total of 15 mL of N,N-dimethylformamide (DMF) was added in three portions, and the reaction was continued for 90 minutes to obtain mixture b; 4 g of chain extender BDO, 5 g of epoxy resin E51 and 20 mL of DMF were added to mixture b, and the temperature was raised to 80°C and reacted at constant temperature for 40 minutes to obtain mixture c; 2 g of halamine antibacterial monomer, 3 g of ultraviolet absorber 2,4-dihydroxybenzophenone and 20 mL of DMF, continue the reaction for 60 minutes to obtain a mixture d; cool to 55°C, add 0.06g of antioxidant 1010, 3g of triethylamine and 10mL of DMF to the mixture d, and neutralize for 45 minutes to obtain a mixture e; adjust the viscosity of the mixture e to 7000Pa / s with DMF, slowly add 5°C deionized water under stirring at 1500rpm, and after the phase inversion is successful, quickly add the remaining deionized water, the total amount of deionized water added is 200mL, and then add 0.8mL of diethylenetriamine, continue emulsification at 25°C for 90 minutes, remove the organic solvent, and obtain a renewable long-lasting antibacterial water-based polyurethane emulsion.

[0104] Example 2

[0105] This embodiment provides a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, the preparation method of which includes the following steps:

[0106] (1) A base fabric (polyester filament knitted fabric) was immersed in a surface modification liquid at a bath ratio of 1:10 at 100°C for 20 minutes to form a surface modification layer on the surface of the base fabric, thereby obtaining a pretreated base fabric; wherein the surface modification liquid comprises: 12 mL / L benzyl alcohol, 0.3 g / L hexadecyltrimethylammonium bromide, and 16 g / L sodium hydroxide;

[0107] (2) Apply the renewable long-lasting antibacterial water-based polyurethane emulsion on the release paper at a coating amount of 180 g / m 2 , drying in an oven at 110°C for 5 minutes to obtain a polyurethane surface layer, laminating the polyurethane surface layer to the surface of the pretreated base fabric at a speed of 7 m / min, drying in an oven at 130°C for 3 minutes, and then removing the release paper to obtain a base fabric containing a polyurethane layer;

[0108] (3) The base fabric containing the polyurethane layer was immersed in a sodium hypochlorite solution with an effective chlorine content of 3000 ppm at a bath ratio of 1:8 for 25 minutes to obtain a high peel strength renewable antibacterial water-based polyurethane synthetic leather.

[0109] The preparation method of the renewable long-lasting antibacterial aqueous polyurethane emulsion described in step (2) above comprises the following steps:

[0110] 35 g of polymer diol (a mixture of PLG and PBA2000 in a mass ratio of 1:2) was added to the reaction equipment, heated to 80°C under vacuum conditions, dehydrated for 2 hours, cooled to 50°C, and then 16 g of diisocyanate (a mixture of IPDI and HMDI in a mass ratio of 3:1) was added, heated to 65°C, and reacted at a constant temperature for 70 minutes to obtain a mixture a; 0.3 g of dibutyltin dilaurate was added to the mixture a, and the temperature was raised to 73°C. During the heating process, a total of 18 mL of N,N-dimethylformamide (DMF) was added in three portions, and the reaction was continued for 100 minutes to obtain a mixture b; 3 g of chain extender BDO, 7 g of epoxy resin E51 and 20 mL of DMF were added to the mixture b, and the temperature was raised to 85°C and reacted at a constant temperature for 45 minutes to obtain a mixture c; 1 g of halamine antibacterial monomer, 4 g of ultraviolet absorber 2,4-dihydroxybenzophenone and 20 mL of DMF, continue the reaction for 80 minutes to obtain a mixture d; cool to 50°C, add 0.03g of antioxidant 1010, 4g of triethylamine and 15mL of DMF to the mixture d, and neutralize for 50 minutes to obtain a mixture e; adjust the viscosity of the mixture e to 7500Pa / s with DMF, slowly add 5°C deionized water under stirring at 1500rpm, and after the phase inversion is successful, quickly add the remaining deionized water, the total amount of deionized water added is 260mL, and then add 0.6mL of diethylenetriamine, continue emulsification at 25°C for 70 minutes, remove the organic solvent, and obtain a renewable long-lasting antibacterial water-based polyurethane emulsion.

[0111] Example 3

[0112] This embodiment provides a high peel strength renewable antibacterial waterborne polyurethane synthetic leather, the preparation method of which includes the following steps:

[0113] (1) Immersing a base fabric (polyester filament knitted fabric) in a surface modification solution at a bath ratio of 1:10 at 120°C for 25 minutes to form a surface modification layer on the surface of the base fabric, thereby obtaining a pretreated base fabric; wherein the surface modification solution comprises: 15 mL / L benzyl alcohol, 0.4 g / L hexadecyltrimethylammonium bromide, and 20 g / L sodium hydroxide;

[0114] (2) Apply the renewable long-lasting antibacterial water-based polyurethane emulsion on the release paper at a coating amount of 150 g / m 2, drying in an oven at a temperature of 110°C for 5 minutes to obtain a polyurethane surface layer, laminating the polyurethane surface layer to the surface of the pretreated base fabric at a speed of 7 m / min, drying in an oven at a temperature of 130°C for 3 minutes, and then removing the release paper to obtain a base fabric containing a polyurethane layer;

[0115] (3) The base fabric containing the polyurethane layer was immersed in a sodium hypochlorite solution with an effective chlorine content of 3000 ppm at a bath ratio of 1:10 for 30 minutes to obtain a high peel strength renewable antibacterial water-based polyurethane synthetic leather.

[0116] The preparation method of the renewable long-lasting antibacterial aqueous polyurethane emulsion described in step (2) above comprises the following steps:

[0117] 40 g of polymer diol (a mixture of PLG and PBA2000 in a mass ratio of 1:2) was added to the reaction equipment, heated to 80°C under vacuum conditions, dehydrated for 2 hours, cooled to 50°C, and then 15 g of diisocyanate (a mixture of IPDI and HMDI in a mass ratio of 3:1) was added, the temperature was raised to 60°C, and the reaction was carried out at a constant temperature for 90 minutes to obtain a mixture a; 0.3 g of dibutyltin dilaurate was added to the mixture a, the temperature was raised to 70°C, and a total of 15 mL of N,N-dimethylformamide (DMF) was added three times during the heating process, and the reaction was continued for 90 minutes to obtain a mixture b; 5 g of chain extender BDO, 8 g of epoxy resin E51 and 20 mL of DMF were added to the mixture b, the temperature was raised to 90°C, and the reaction was carried out at a constant temperature for 40 minutes to obtain a mixture c; 3 g of halamine antibacterial monomer, 5 g of ultraviolet absorber 2,4-dihydroxybenzophenone and 20 mL of DMF, continue the reaction for 60 minutes to obtain a mixture d; cool to 55°C, add 0.01g of antioxidant 1010, 3g of triethylamine and 15mL of DMF to the mixture d, and neutralize for 60 minutes to obtain a mixture e; adjust the viscosity of the mixture e to 8000Pa / s with DMF, slowly add 5°C deionized water under stirring at 1500rpm, and after the phase inversion is successful, quickly add the remaining deionized water, the total amount of deionized water added is 200mL, and then add 1mL of diethylenetriamine, continue emulsification at 25°C for 60 minutes, remove the organic solvent, and obtain a renewable long-lasting antibacterial water-based polyurethane emulsion.

[0118] Comparative Example 1

[0119] This comparative example provides a waterborne polyurethane synthetic leather. For details, refer to Example 1, except that the base fabric is not surface-modified, and no halamine antibacterial monomer or ultraviolet absorber is added to the waterborne polyurethane emulsion.

[0120] Comparative Example 2

[0121] This comparative example provides a waterborne polyurethane synthetic leather, which is specifically described in Example 1, except that no halogenamine antibacterial monomer or ultraviolet absorber is added to the waterborne polyurethane emulsion.

[0122] Comparative Example 3

[0123] This comparative example provides a waterborne polyurethane synthetic leather, which is specifically described in Example 1, except that the base fabric is not surface-modified, and epoxy resin E51, halamine antibacterial monomer, and ultraviolet absorber are not added to the waterborne polyurethane emulsion.

[0124] Comparative Example 4

[0125] This comparative example provides a waterborne polyurethane synthetic leather, which is specifically described in Example 1, except that no ultraviolet absorber is added to the waterborne polyurethane emulsion.

[0126] The high-peel-strength, renewable antibacterial waterborne polyurethane synthetic leather prepared in Example 1 and the waterborne polyurethane synthetic leather prepared in Comparative Examples 1-3 were subjected to peel strength testing according to the "GB / T 2791-1995 Adhesive T-peel Strength Test Method: Flexible Material to Flexible Material" standard. The test conditions were a tensile rate of 100 mm / min and a gauge distance of 100 mm. The test results are shown in Table 1.

[0127] SEM tests were performed on the surface-modified base fabric fibers in step (1) of Example 1 and the non-surface-modified base fabric fibers in Comparative Example 1. The results are shown in Figures 1 and 2.

[0128] Table 1 Peel strength test results

[0129] As can be seen from the data in Table 1, the peel strength between the aqueous polyurethane emulsion prepared by polymerization with epoxy resin E51 and the base fabric (Comparative Example 1) is significantly greater than that of the solution without epoxy resin E51 (Comparative Example 3), and the alkali reduction treatment can effectively improve the peel strength between the polyurethane resin and the base fabric. This is because alkali reduction can create a microscopic rough structure on the fiber surface (see Figures 1 and 2), and the rough surface can produce a mechanical meshing effect with the polyurethane surface layer, achieving the purpose of improving the peel strength. The peel strength of Example 1 and Comparative Example 2 shows that the addition of halamine antibacterial monomers and ultraviolet absorbers (Example 1) does not have a significant effect on the peel strength.

[0130] The high-peel-strength, renewable antibacterial water-based polyurethane synthetic leather prepared in Example 1, as well as the water-based polyurethane synthetic leathers prepared in Comparative Examples 2 and 4, were tested for antibacterial properties. Antibacterial rates were determined according to the standard "GB / T 20944.1-2007 Evaluation of Antibacterial Properties of Textiles - Part 1: Agar Plate Diffusion Method." Washability was tested by immersing the sample in a 2g / L detergent solution prepared with a phosphate-free ECE standard synthetic detergent in a 25°C waterbath for 10 minutes, then thoroughly rinsing with distilled water and air-drying (this was considered one wash). Lightfastness was tested by irradiating the sample under simulated sunlight using a Q-SUN-Xe-2-HS lightfastness tester. The antibacterial rates were then analyzed before and after irradiation. The results are shown in Table 2.

[0131] Table 2 Antibacterial performance test results

[0132] Note: “-” indicates no obvious antibacterial effect; “ / ” indicates not measured.

[0133] As can be seen from the data in Table 2, the synthetic leather without the addition of halamine antibacterial monomer (Comparative Example 2) has no obvious antibacterial effect, and the synthetic leather with the addition of halamine antibacterial monomer (Comparative Example 4 and Example 1) has a good antibacterial effect and good washability. By comparing Comparative Example 4 and Example 1, it can be seen that the ultraviolet absorber has no obvious effect on the washability of the synthetic leather, but can significantly improve the light resistance of the synthetic leather. The synthetic leather prepared in Example 1 was tested for antibacterial renewability. The data in Table 2 show that the aqueous polyurethane emulsion containing halamine antibacterial monomer has good antibacterial renewability. The halamine antibacterial monomer can obtain antibacterial renewability by repeated dehalogenation and halogenation. The schematic diagram of the dehalogenation and halogenation process is shown in Figure 3. NH generates N-Cl under the action of sodium hypochlorite (NaClO), and N-Cl is hydrolyzed and releases Cl under the action of water. + , and NH is generated at the same time. In addition, the ultraviolet absorber has no obvious effect on the regeneration of halamine antibacterial monomers.

[0134] 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 principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A preparation method of a renewable antibacterial aqueous polyurethane synthetic leather with high peel strength, characterized in that, It includes the following steps: Immerse the base fabric in the surface modification liquid to form a surface modification layer on the surface of the base fabric, and obtain a pretreated base fabric; The composition of the surface modification liquid includes: benzyl alcohol 10 - 15 mL / L, accelerator 0.3 - 0.5 g / L, sodium hydroxide 15 - 20 g / L; the bath ratio of the immersion is 1:5 - 10; the temperature of the immersion is 100 - 120 °C; the time of the immersion is 20 - 30 min; Coat the renewable and durable antibacterial aqueous polyurethane emulsion on the release paper, dry it to obtain a polyurethane surface layer; bond the pretreated base fabric to the polyurethane surface layer, dry it, and then peel off the release paper to obtain a base fabric containing a polyurethane layer; Chlorinate the base fabric containing a polyurethane layer to obtain a high peel strength renewable antibacterial aqueous polyurethane synthetic leather; Among them, the preparation method of the renewable and durable antibacterial aqueous polyurethane emulsion includes the following steps: (1) Mix the polymer diol and the diisocyanate for reaction to obtain mixture a; (2) Mix mixture a, dibutyltin dilaurate and N,N-dimethylformamide for reaction to obtain mixture b; (3) Mix mixture b, chain extender, epoxy resin and N,N-dimethylformamide for reaction to obtain mixture c; (4) Mix mixture c, haloamine antibacterial monomer, ultraviolet absorber and N,N-dimethylformamide for reaction to obtain mixture d; (5) Mix mixture d, antioxidant, triethylamine and N,N-dimethylformamide for neutralization reaction to obtain mixture e; (6) Use N,N-dimethylformamide to adjust the viscosity of mixture e, and then mix it with water and diethylenetriamine for emulsification to obtain a renewable and durable antibacterial aqueous polyurethane emulsion; The mass-volume ratio of the polymer diol in step (1) to the chain extender, epoxy resin, and N,N-dimethylformamide in step (3) is 30 - 40 g: 3 - 5 g: 5 - 8 g: 15 - 20 mL; The ultraviolet absorber in step (4) is 2,4-dihydroxybenzophenone; The mass-volume ratio of the polymer diol in step (1) to the haloamine antibacterial monomer, ultraviolet absorber, and N,N-dimethylformamide in step (4) is 30 - 40 g: 1 - 3 g: 2 - 5 g: 15 - 25 mL; The haloamine antibacterial monomer described in step (4) is 3-(2,3-dihydroxypropyl)-5,5-dimethylhydantoin, and its structural formula is as follows:

2. The preparation method of a high peel strength renewable antibacterial aqueous polyurethane synthetic leather according to claim 1, characterized in that, The base fabric is one of polyester filament knitted fabric, polyester filament woven fabric, polyester staple fiber knitted fabric, polyester staple fiber woven fabric, polyester staple fiber spunlace non-woven fabric, and polyester staple fiber needle-punched non-woven fabric.

3. The preparation method of a high peel strength renewable antibacterial aqueous polyurethane synthetic leather according to claim 1, characterized in that, The coating amount of the renewable and persistent antibacterial aqueous polyurethane emulsion coated on the release paper is 150-200 g / m 2 .

4. The preparation method of a high peel strength renewable antibacterial aqueous polyurethane synthetic leather according to claim 3, characterized in that, The chlorination treatment is immersion in a sodium hypochlorite solution; the available chlorine content of the sodium hypochlorite solution is 3000 ppm; the bath ratio of the immersion is 1:5 - 10; the time of the immersion is 20 - 30 min.

5. The preparation method of a high peel strength renewable antibacterial waterborne polyurethane synthetic leather according to claim 1 or 2, characterized in that In the preparation method of the renewable and durable antibacterial aqueous polyurethane emulsion, the mass ratio of the polymer diol to the diisocyanate in step (1) is 30 - 40: 15 - 20; The temperature of the reaction in step (1) is The mass-volume ratio of the polymer diol described in step (1) to the dibutyltin dilaurate and N,N-dimethylformamide described in step (2) is 30-40 g: 0.1-0.3 g: 10-20 mL; The temperature of the reaction described in step (2) is 70-75 °C; the time of the reaction described in step (2) is 90-120 min; The temperature of the reaction described in step (3) is 80-90 °C; the time of the reaction described in step (3) is 30-45 min.

6. The preparation method of a high peel strength renewable antibacterial aqueous polyurethane synthetic leather according to claim 5, characterized in that, In the preparation method of the renewable and durable antibacterial aqueous polyurethane emulsion, the temperature of the reaction described in step (4) is 80-90 °C; the time of the reaction described in step (4) is 60-90 min.

7. The preparation method of a high peel strength renewable antibacterial waterborne polyurethane synthetic leather according to claim 6, characterized in that, In the preparation method of the renewable and durable antibacterial aqueous polyurethane emulsion, the mass-volume ratio of the polymer diol described in step (1) to the antioxidant, triethylamine, and N,N-dimethylformamide described in step (5) is 30-40 g: 0.01-0.1 g: 3-5 g: 5-15 mL; The temperature of the neutralization reaction described in step (5) is 50-60 °C; the time of the neutralization reaction described in step (5) is 30-60 min.

8. The preparation method of a renewable antibacterial aqueous polyurethane synthetic leather with high peel strength according to claim 1 or 7, characterized in that, In the preparation method of the renewable and durable antibacterial aqueous polyurethane emulsion, the viscosity described in step (6) is 7000-8000 Pa / s; The mass-volume ratio of the polymer diol described in step (1) to the water and diethylenetriamine described in step (6) is 30-40 g: 200-300 mL: 0.5-1 mL; The temperature of the emulsification described in step (6) is 25-30 °C; the time of the emulsification described in step (6) is 60-90 min.

9. A high peel strength renewable antibacterial aqueous polyurethane synthetic leather prepared by the preparation method of a high peel strength renewable antibacterial aqueous polyurethane synthetic leather according to any one of claims 1-8.

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