Oxidation-aging-resistant anti-cracking leather and preparation method thereof

Abstract

The invention relates to the field of leather, in particular to oxidation-aging-resistant anti-cracking leather and a preparation method thereof. The method is used for solving the problems that existing leather is extremely prone to oxidation aging and cracks are generated. According to the leather, the phenolic hydroxyl isoquinoline, the benzophenone p-phenylenediamine and the modified polyurethane emulsion are used as coatings, and phenolic hydroxyl groups in phenolic hydroxyl isoquinoline molecules have good hydrogen atom transfer capacity and are combined with reactive oxygen free radicals generated in the leather oxidation process; benzophenone-based p-phenylenediamine has good ultraviolet absorption capacity and anti-aging capacity, a cross-linked network exists in the modified polyurethane emulsion, so that the anti-cracking performance of leather is improved, and the surface of the leather is coated with the modified polyurethane emulsion, so that the finally prepared leather material has excellent oxidation aging resistance and anti-cracking characteristics; and the durability and the use comfort of the product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of leather, in particular to a kind of oxidation aging resistant and anti-cracking leather and preparation method thereof. BACKGROUND

[0002] In the field of leather products, oxidation aging resistance and anti-cracking problem is always a challenge faced by the industry. Ordinary leather material is prone to oxidation aging phenomenon when exposed to air for a long time or subjected to ultraviolet radiation, causing the leather to become hard, lose luster, and even crack, which seriously affects the quality and service life of leather products. The present application provides a kind of oxidation aging resistant and anti-cracking leather prepared by coating phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion, which is of great significance to improve the performance of leather products and prolong their service life. SUMMARY

[0003] In order to overcome the above technical problems, the purpose of the present application is to provide a kind of oxidation aging resistant and anti-cracking leather and preparation method thereof, which solves the problem of existing leather prone to oxidation aging phenomenon and crack.

[0004] The purpose of the present application can be achieved by the following technical solutions: In a first aspect, the present application provides a kind of oxidation aging resistant and anti-cracking leather, comprising the following weight parts: Phenolic hydroxyl isoquinoline 3-5 parts, benzophenone-based p-phenylenediamine 5-10 parts and modified polyurethane emulsion 50-100 parts.

[0005] The phenolic hydroxyl isoquinoline is prepared by the following steps: 2,6-dihydroxybenzaldehyde and anhydrous ethanol are added to a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, stirred at 50-100 r / min for 6-10 min, 2-methoxyphenethylamine is added dropwise, the dropwise time is controlled for 3 min, 3A molecular sieves are added, stirred at 25 DEG C for 30 min, the molecular sieves are removed by filtration, the ethanol is removed by vacuum filtration, phosphoric acid solution is added, the temperature is raised to 70 DEG C, refluxed for 3 h, deionized water is added, the pH is adjusted to 8-9 with saturated sodium bicarbonate solution, stirred for 30 min, the organic phase is collected by extraction with ethyl acetate, anhydrous sodium sulfate is added for drying, oxalic acid is dissolved in ethyl acetate and added to the organic phase, dichloromethane is added to precipitate the solid, distilled water is added after filtration, stirred for 20 min, the pH is adjusted to 8-9 with saturated sodium bicarbonate solution, stirred for 30 min, the organic phase is collected by extraction with ethyl acetate, anhydrous sodium sulfate is added for drying, activated carbon is added, filtered and rotary evaporated to obtain phenolic hydroxyl isoquinoline;

[0006] As a further scheme of the present application: the amount ratio of the 2,6-dihydroxybenzaldehyde, anhydrous ethanol, 2-methoxyphenethylamine, 3A molecular sieve, phosphoric acid solution, deionized water, oxalic acid and ethyl acetate is 0.022-0.044 mol: 20-40 mL: 0.02-0.04 mol: 0.4-0.8 g: 20-40 mL: 50-100 mL: 1.8-3.6 g: 200-400 mL.

[0007] As a further scheme of the present application: the mass fraction of the phosphoric acid solution is 85%.

[0008] As a further scheme of the present application: the benzophenone-based p-phenylenediamine is prepared by the following steps: Step A1: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and epichlorohydrin are added to a three-necked flask equipped with a thermometer, transferred to an oil bath, magnetically stirred for 10-20 min, heated to 150°C for 8 h, cooled to 24-26°C, dichloromethane is added, washed with deionized water for 5-7 times, and the dichloromethane is evaporated and dried to obtain an intermediate product;

[0009] Step A2: 2-hydroxybenzophenone and dichloromethane are added to a three-necked flask equipped with a stirrer, transferred to an ice water bath, protected by nitrogen, triethylamine is added dropwise and stirred for 5 min, the intermediate product is added and reacted for 1-2 h, quenched with ice water, the organic phase is collected by extraction, the dichloromethane is removed by evaporation and rotary evaporation, and the benzophenone-based p-phenylenediamine is separated by petroleum ether column chromatography;

[0010] As a further scheme of the present application: the amount ratio of the N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, epichlorohydrin and dichloromethane in step A1 is 0.01-0.02 mol: 0.012-0.024 mol: 50-100 mL.

[0011] As a further scheme of the present application: the amount ratio of the 2-hydroxybenzophenone, dichloromethane, triethylamine and intermediate product in step A2 is 0.11-0.22 mol: 100-200 mL: 0.11-0.22 mol: 0.1-0.2 mol.

[0012] As a further scheme of the present application: the modified polyurethane emulsion is prepared by the following steps: Polyethylene glycol is added to a three-necked flask equipped with a stirrer, a vacuum pump and a glass stopper, is transferred to a heating device, is heated to 120 DEG C, the vacuum pump is started at 100 r / min, the negative pressure is 2h, the vacuum pump is disconnected when the temperature is lowered to 80 DEG C, nitrogen is introduced, isophorone diisocyanate is added dropwise, the reaction is carried out for 1h, dibutyltin dilaurate is added, the reaction is carried out for 3h, the temperature is lowered to 70 DEG C, 2,2-dimethylol propionic acid is added, the reaction is carried out for 1.5h, the temperature is lowered to 50 DEG C, 3,3'-dimethylbenzidine is added, the reaction is carried out for 3h, triethylamine is added, the temperature is lowered to 24-26 DEG C, stirring is carried out for 30min, potassium chloride is added, stirring is carried out for 5-10min, deionized water is added, the solid content of the emulsion is controlled to be 30-40%, stirring is carried out at 1500 r / min for 30min, and a modified polyurethane emulsion is obtained.

[0013] As a further scheme of the application: the amount ratio of the polyethylene glycol, isophorone diisocyanate, dibutyltin dilaurate, 2,2-dimethylol propionic acid, 3,3'-dimethylbenzidine, triethylamine and potassium chloride is 25-50g: 50-100mmol: 0.5-1mmol: 15-30mmol: 10-20mmol: 15-30mmol: 5-10mmol.

[0014] As a further scheme of the application: the model of the polyethylene glycol is PEG-1000.

[0015] In a second aspect, the application provides a preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step one: phenolic hydroxyl isoquinoline 3-5 parts, benzophenone-based p-phenylenediamine 5-10 parts and modified polyurethane emulsion 50-100 parts are weighed according to weight parts, and are prepared for use; Step two: the phenolic hydroxyl isoquinoline, the benzophenone-based p-phenylenediamine and the modified polyurethane emulsion are mixed, are coated on the leather, and then are heated at 100-140 DEG C for 1-6h to obtain the oxidation aging resistant and anti-cracking leather.

[0016] The application has the following beneficial effects: The oxidation aging resistant and anti-cracking leather provided by the application takes the modified polyurethane emulsion as a basic framework, adds the phenolic hydroxyl isoquinoline and the benzophenone-based p-phenylenediamine as an antioxidant and an ultraviolet absorber to obtain a leather coating, and ensures that the leather can maintain long-lasting beauty and use performance under various environmental conditions after being coated on the surface of the leather, thereby prolonging the service life of the leather.

[0017] The application discloses a kind of oxidation aging resistant anti-cracking leather, first, phenolic hydroxyl isoquinoline is prepared by using 2,6-dihydroxybenzaldehyde and 2-methoxyphenethylamine, phenolic hydroxyl in molecule is easy to release hydrogen atom, combine with active oxygen free radical generated in leather oxidation process, terminate free radical chain reaction, inhibit the further spread of oxidation, isoquinoline ring is nitrogen-containing heterocyclic aromatic structure, can enhance the electron cloud density of phenolic hydroxyl by conjugation effect, improve hydrogen supply capacity, indirectly inhibit oxidation reaction, benzophenone-based p-phenylenediamine is prepared by using N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, epichlorohydrin and 2-hydroxybenzophenone, the amino group of p-phenylenediamine in benzophenone-based p-phenylenediamine can provide active hydrogen atom, effectively inhibit the aging process, benzophenone can efficiently absorb UV-B and UV-A, release by intramolecular resonance effect converts ultraviolet energy into harmless heat energy, avoid that ultraviolet ray directly acts on leather, the synergistic effect of both improves the anti-oxidation performance and anti-aging performance of leather, isophorone diisocyanate contains 2 isocyanate groups, esterification reaction occurs with the hydroxyl group of polyethylene glycol, and a prepolymer containing urethane bond is generated, the hydroxyl group in 2,2-dimethylol propionic acid can occur esterification reaction with the remaining isocyanate in the prepolymer, 3,3'-dimethylbenzidine contains 2 amino groups, and the urea reaction occurs between the amino group and the remaining isocyanate in the prepolymer, and a urea bond is generated, triethylamine is used as a neutralizing agent, and acid-base neutralization reaction occurs with the carboxyl group introduced by 2,2-dimethylol propionic acid, potassium ions in potassium chloride form cation-π interaction with the biphenyl group, and a modified polyurethane emulsion with a non-covalent physical crosslinking network is constructed, polyethylene glycol is used as a soft segment to improve the toughness of the polyurethane, the cation-π interaction provides physical crosslinking points between polymer molecular chains, and the reversibility of the cation-π interaction, as well as the π-π stacking effect and hydrogen bond within the polymer, enable the coating to exhibit good tensile strength and toughness, thereby improving the anti-cracking performance of the leather, the crosslinking network in the modified polyurethane emulsion and the polyethylene glycol improve the tensile strength and toughness of the leather, and the phenolic hydroxyl isoquinoline and the benzophenone-based p-phenylenediamine provide good anti-oxidation performance and anti-aging performance, thereby effectively preventing the leather from cracking due to oxidation and aging during long-term use; the leather has good stability and service life, meets the market demand for higher quality leather products, and is suitable for application scenarios such as automotive interiors and outdoor equipment. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0019] Embodiment 1: The present embodiment is a preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step S1: 0.022 mol of 2,6-dihydroxybenzaldehyde and 20 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, stirred at 50 r / min for 6 min, 0.02 mol of 2-methoxyphenethylamine was added dropwise, the dropwise time was controlled for 3 min, 0.4 g of 3A molecular sieve was added, stirred at 25℃ for 30 min, the molecular sieve was removed by filtration, the ethanol was removed by vacuum filtration, 20 mL of phosphoric acid solution was added, the temperature was increased to 70℃, and the reaction was refluxed for 3 h, 50 mL of deionized water was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, anhydrous sodium sulfate was added for drying, 1.8 g of oxalic acid was dissolved in 200 mL of ethyl acetate and added to the organic phase, dichloromethane was added to precipitate the solid, after filtration, distilled water was added, stirred for 20 min, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, anhydrous sodium sulfate was added for drying, activated carbon was added, after filtration, rotary evaporation was performed, and a phenolic hydroxyl isoquinoline was obtained; Step S2: 0.01 mol of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.012 mol of epichlorohydrin were added to a three-necked flask equipped with a thermometer, transferred to an oil bath, magnetically stirred for 10 min, the temperature was increased to 150℃, and the reaction was carried out for 8 h, cooled to 24℃, 50 mL of dichloromethane was added, washed with deionized water for 5 times, the dichloromethane was evaporated, and the intermediate product was obtained after drying; Step S3: 0.11 mol of 2-hydroxybenzophenone and 100 mL of dichloromethane were added to a three-necked flask equipped with a stirrer, transferred to an ice water bath, protected by nitrogen, 0.11 mol of triethylamine was added dropwise and stirred for 5 min, 0.1 mol of the intermediate product was added and reacted for 1 h, quenched with ice water, the organic phase was collected by extraction, the dichloromethane was removed by evaporation and rotary evaporation, and the benzophenone-p-phenylenediamine was obtained by column chromatography with petroleum ether; Step S4: 25 g of polyethylene glycol was added to a three-necked flask equipped with a stirrer, vacuum pump and glass stopper, transferred to a heating device and warmed to 120°C, the vacuum pump was started at 100 r / min, and the vacuum was 2 h. The vacuum pump was disconnected at 80°C, nitrogen was introduced, 50 mmol of isophorone diisocyanate was added dropwise and reacted for 1 h, 0.5 mmol of dibutyltin dilaurate was added and reacted for 3 h, the temperature was lowered to 70°C, 15 mmol of 2,2-dihydroxymethylpropionic acid was added and reacted for 1.5 h, the temperature was lowered to 50°C, 10 mmol of 3,3'-dimethylbenzidine was added and reacted for 3 h, 15 mmol of triethylamine was added, the temperature was lowered to 24°C and stirred for 30 min, 5 mmol of potassium chloride was added and stirred for 5 min, deionized water was added to control the emulsion solid content to 30%, and stirred at 1500 r / min for 30 min to obtain a modified polyurethane emulsion; Step S5: phenolic hydroxyl isoquinoline 3 parts, benzophenone p-phenylenediamine 5 parts and modified polyurethane emulsion 50 parts were weighed according to weight parts and prepared for use; Step S6: phenolic hydroxyl isoquinoline, benzophenone p-phenylenediamine and modified polyurethane emulsion were mixed, coated on the leather and then heated at 100°C for 1 h to obtain an oxidation aging resistant and anti-cracking leather.

[0020] Example 2: This example is a preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step S1: 0.033 mol of 2,6-dihydroxybenzaldehyde and 30 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, stirred at 75 r / min for 8 min, 0.03 mol of 2-methoxyphenethylamine was added dropwise, the dropwise time was controlled for 3 min, 0.6 g of 3A molecular sieve was added, stirred at 25°C for 30 min, the molecular sieve was removed by filtration, the ethanol was removed by vacuum filtration under reduced pressure, 30 mL of phosphoric acid solution was added, warmed to 70°C, refluxed for 3 h, 75 mL of deionized water was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, anhydrous sodium sulfate was added for drying, 2.7 g of oxalic acid was dissolved in 300 mL of ethyl acetate and added to the organic phase, dichloromethane was added to precipitate the solid, filtered, distilled water was added, stirred for 20 min, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, anhydrous sodium sulfate was added for drying, activated carbon was added, filtered and rotary evaporated to obtain phenolic hydroxyl isoquinoline; Step S2: 0.015 mol N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.018 mol epichlorohydrin were added into a three-necked flask equipped with a thermometer, which was transferred into an oil bath, magnetically stirred for 15 min, heated to 150℃ for 8 h, cooled to 25℃, 75 mL dichloromethane was added, washed with deionized water for 6 times, and dichloromethane was removed by evaporation to obtain an intermediate product; Step S3: 0.165 mol 2-hydroxybenzophenone and 150 mL dichloromethane were added into a three-necked flask equipped with a stirrer, which was transferred into an ice water bath, protected by nitrogen, 0.165 mol triethylamine was added dropwise and stirred for 5 min, 0.15 mol intermediate product was added and reacted for 1.5 h, quenched with ice water, the organic phase was collected by extraction, dichloromethane was removed by evaporation, and benzophenone-based p-phenylenediamine was obtained by column chromatography with petroleum ether; Step S4: 37.5 g polyethylene glycol was added into a three-necked flask equipped with a stirrer, a vacuum pump and a glass stopper, which was transferred into a heating device and heated to 120℃, the vacuum pump was started at 100 r / min, and the negative pressure was 2 h, the vacuum pump was disconnected after cooling to 80℃, nitrogen was introduced, 75 mmol isophorone diisocyanate was added and reacted for 1 h, 0.75 mmol dibutyltin dilaurate was added and reacted for 3 h, 22.5 mmol 2,2-dimethylol propionic acid was added and reacted for 1.5 h, 15 mmol 3,3'-dimethylphenylenediamine was added and reacted for 3 h, 22.5 mmol triethylamine was added, cooled to 25℃ and stirred for 30 min, 7.5 mmol potassium chloride was added and stirred for 7 min, deionized water was added to control the emulsion solid content to 35%, and stirred at 1500 r / min for 30 min to obtain a modified polyurethane emulsion; Step S5: phenolic hydroxyisoquinoline 4 parts, benzophenone-based p-phenylenediamine 7.5 parts and modified polyurethane emulsion 75 parts were weighed according to weight parts, and reserved; Step S6: phenolic hydroxyisoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion were mixed, coated on the leather, and then heated at 120℃ for 3 h to obtain an oxidation aging resistant and anti-cracking leather.

[0021] Example 3: A preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step S1: 0.044 mol of 2,6-dihydroxybenzaldehyde, 40 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, stirred at 100 r / min for 10 min, 0.04 mol of 2-methoxyphenethylamine was added dropwise, the dropwise time was controlled for 3 min, 0.8 g of 3A molecular sieve was added, stirred at 25°C for 30 min, the molecular sieve was removed by filtration, the ethanol was removed by vacuum filtration, 40 mL of phosphoric acid solution was added, the temperature was raised to 70°C, and the reaction was refluxed for 3 h, 100 mL of deionized water was added, the pH was adjusted to 9 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, 3.6 g of oxalic acid was dissolved in 400 mL of ethyl acetate and added to the organic phase, dichloromethane was added to precipitate the solid, after filtration, distilled water was added, stirred for 20 min, the pH was adjusted to 9 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, added activated carbon, filtered and rotary evaporated to obtain phenolic hydroxyisoquinoline; Step S2: 0.02 mol of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.024 mol of epichlorohydrin were added to a three-necked flask equipped with a thermometer, transferred to an oil bath, magnetically stirred for 20 min, the temperature was raised to 150°C and reacted for 8 h, cooled to 26°C, 100 mL of dichloromethane was added, washed with deionized water for 7 times, evaporated to remove dichloromethane, and dried to obtain an intermediate product; Step S3: 0.22 mol of 2-hydroxybenzophenone and 200 mL of dichloromethane were added to a three-necked flask equipped with a stirrer, transferred to an ice water bath, protected by nitrogen, 0.22 mol of triethylamine was added dropwise and stirred for 5 min, 0.2 mol of the intermediate product was added and reacted for 2 h, quenched with ice water, the organic phase was collected by extraction, evaporated to remove dichloromethane, and separated by petroleum ether column chromatography to obtain benzophenone-p-phenylenediamine; Step S4: 50 g of polyethylene glycol was added to a three-necked flask equipped with a stirrer, a vacuum pump and a glass stopper, transferred to a heating device and heated to 120°C, the vacuum pump was turned on at 100 r / min, and the negative pressure was 2 h, the temperature was lowered to 80°C, the vacuum pump was disconnected, nitrogen was introduced, 100 mmol of isophorone diisocyanate was added and reacted for 1 h, 1 mmol of dibutyltin dilaurate was added and reacted for 3 h, the temperature was lowered to 70°C, 30 mmol of 2,2-dimethylol propionic acid was added and reacted for 1.5 h, the temperature was lowered to 50°C, 20 mmol of 3,3'-dimethylphenylhydrazine was added and reacted for 3 h, 30 mmol of triethylamine was added, the temperature was lowered to 26°C and stirred for 30 min, 10 mmol of potassium chloride was added and stirred for 10 min, deionized water was added to control the solid content of the emulsion to 40%, and stirred at 1500 r / min for 30 min to obtain a modified polyurethane emulsion; Step S5: 5 parts of phenolic hydroxyisoquinoline, 10 parts of benzophenone-based p-phenylenediamine and 100 parts of modified polyurethane emulsion were weighed according to the weight parts, and were prepared for use; Step S6: phenolic hydroxyisoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion were mixed, coated on the leather, and then heated at 140°C for 6h to obtain the anti-oxidation and anti-cracking leather.

[0022] Comparative Example 1: The present comparative example is a preparation method of an anti-oxidation and anti-cracking leather, comprising the following steps: Step S1: 0.01 mol of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.012 mol of epichlorohydrin were added to a three-necked flask equipped with a thermometer, transferred to an oil bath, magnetically stirred for 10 min, heated to 150°C for 8h, cooled to 24°C, 50 mL of dichloromethane was added, washed with deionized water for 5 times, and the dichloromethane was evaporated to obtain an intermediate product; Step S2: 0.11 mol of 2-hydroxybenzophenone and 100 mL of dichloromethane were added to a three-necked flask equipped with a stirrer, transferred to an ice water bath, protected by nitrogen, 0.11 mol of triethylamine was added dropwise and stirred for 5 min, 0.1 mol of the intermediate product was added and reacted for 1h, quenched with ice water, the organic phase was collected by extraction, and the dichloromethane was removed by evaporation and rotary evaporation to obtain benzophenone-based p-phenylenediamine by column chromatography with petroleum ether; Step S3: 25 g of polyethylene glycol was added to a three-necked flask equipped with a stirrer, a vacuum pump and a glass stopper, transferred to a heating device, heated to 120°C, the vacuum pump was turned on at 100 r / min, and the negative pressure was 2h, the vacuum pump was turned off when the temperature was lowered to 80°C, nitrogen was introduced, 50 mmol of isophorone diisocyanate was added and reacted for 1h, 0.5 mmol of dibutyltin dilaurate was added and reacted for 3h, the temperature was lowered to 70°C, 15 mmol of 2,2-dimethylol propionic acid was added and reacted for 1.5h, the temperature was lowered to 50°C, 10 mmol of 3,3'-dimethylphenylenediamine was added and reacted for 3h, 15 mmol of triethylamine was added, the temperature was lowered to 24°C and stirred for 30 min, 5 mmol of potassium chloride was added and stirred for 5 min, deionized water was added to control the solid content of the emulsion to 30%, and stirred at 1500 r / min for 30 min to obtain a modified polyurethane emulsion; Step S4: 5 parts of benzophenone-based p-phenylenediamine and 50 parts of modified polyurethane emulsion were weighed according to the weight parts, and were prepared for use; Step S5: benzophenone-based p-phenylenediamine and modified polyurethane emulsion were mixed, coated on the leather, and then heated at 100°C for 1h to obtain the anti-oxidation and anti-cracking leather.

[0023] Comparative Example 2: The present comparative example is a preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step S1: 0.022 mol 2,6-dihydroxybenzaldehyde, 20 mL anhydrous ethanol were added into a three-necked flask equipped with a stirrer, a thermometer and a reflux condenser, stirred at 50 r / min for 6 min, 0.02 mol 2-methoxyphenethylamine was added dropwise, the dropwise time was controlled for 3 min, 0.4 g 3A molecular sieve was added, stirred at 25℃ for 30 min, the molecular sieve was removed by filtration, the ethanol was removed by vacuum filtration, 20 mL phosphoric acid solution was added, the temperature was increased to 70℃, and the reaction was refluxed for 3 h, 50 mL deionized water was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, 1.8 g oxalic acid was dissolved in 200 mL ethyl acetate and added to the organic phase, dichloromethane was added to precipitate the solid, distilled water was added after filtration, stirred for 20 min, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, activated carbon was added, filtered and rotary evaporated to obtain phenolic hydroxyisoquinoline; Step S2: 25 g polyethylene glycol was added to a three-necked flask equipped with a stirrer, a vacuum pump and a glass stopper, transferred to a heating device and heated to 120℃, the vacuum pump was started at 100 r / min, and the negative pressure was 2 h, the vacuum pump was disconnected after cooling to 80℃, nitrogen was introduced, 50 mmol isophorone diisocyanate was added dropwise and reacted for 1 h, 0.5 mmol dibutyltin dilaurate was added and reacted for 3 h, the temperature was lowered to 70℃, 15 mmol 2,2-dimethylol propionic acid was added and reacted for 1.5 h, the temperature was lowered to 50℃, 10 mmol 3,3'-dimethylbenzidine was added and reacted for 3 h, 15 mmol triethylamine was added, the temperature was lowered to 24℃ and stirred for 30 min, 5 mmol potassium chloride was added and stirred for 5 min, deionized water was added to control the emulsion solid content to 30%, and stirred at 1500 r / min for 30 min to obtain a modified polyurethane emulsion; Step S3: phenolic hydroxyisoquinoline 3 parts, modified polyurethane emulsion 50 parts were weighed according to weight parts, and reserved; Step S4: the phenolic hydroxyisoquinoline and the modified polyurethane emulsion were mixed, coated onto the leather, and then heated at 100℃ for 1 h to obtain an oxidation aging resistant and anti-cracking leather.

[0024] Comparative Example 3: The present comparative example is a preparation method of an oxidation aging resistant and anti-cracking leather, comprising the following steps: Step S1: 0.022 mol of 2,6-dihydroxybenzaldehyde, 20 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, stirred at 50 r / min for 6 min, 0.02 mol of 2-methoxyphenethylamine was added dropwise, the dropping time was controlled for 3 min, 0.4 g of 3A molecular sieve was added, stirred at 25℃ for 30 min, the molecular sieve was removed by filtration, the ethanol was removed by vacuum filtration, 20 mL of phosphoric acid solution was added, the temperature was raised to 70℃, and the reaction was refluxed for 3 h, 50 mL of deionized water was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, 1.8 g of oxalic acid was dissolved in 200 mL of ethyl acetate and added to the organic phase, dichloromethane was added to precipitate the solid, after filtration, distilled water was added, stirred for 20 min, the pH was adjusted to 8 with saturated sodium bicarbonate solution, stirred for 30 min, extracted with ethyl acetate, the organic phase was collected, dried with anhydrous sodium sulfate, activated carbon was added, filtered and rotary evaporated to obtain phenolic hydroxyisoquinoline; Step S2: 0.01 mol of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 0.012 mol of epichlorohydrin were added to a three-necked flask equipped with a thermometer, transferred to an oil bath, magnetically stirred for 10 min, heated to 150℃ and reacted for 8 h, cooled to 24℃, 50 mL of dichloromethane was added, washed with deionized water for 5 times, evaporated to remove dichloromethane, and dried to obtain an intermediate product; Step S3: 0.11 mol of 2-hydroxybenzophenone and 100 mL of dichloromethane were added to a three-necked flask equipped with a stirrer, transferred to an ice water bath, protected by nitrogen, 0.11 mol of triethylamine was added dropwise and stirred for 5 min, 0.1 mol of the intermediate product was added and reacted for 1 h, quenched with ice water, the organic phase was collected by extraction, evaporated to remove dichloromethane, and separated by petroleum ether column chromatography to obtain benzophenone-p-phenylenediamine; Step S4: phenolic hydroxyisoquinoline 3 parts, benzophenone-p-phenylenediamine 5 parts, and polyurethane emulsion 50 parts were weighed according to weight parts, and reserved; Step S5: phenolic hydroxyisoquinoline, benzophenone-p-phenylenediamine, and polyurethane emulsion were mixed, coated onto the leather, and then heated at 100℃ for 1 h to obtain an oxidation aging resistant and anti-cracking leather.

[0025] Performance test The leathers of Examples 1-3 and Comparative Examples 1-3 were tested for anti-cracking performance according to SATRA TM30-1995 standard, and pant-type tearing data was obtained; The leather of Example 1-3 and Comparative Example 1-3 was subjected to the determination of elongation at break according to QB-T 2710-2005 Leather Physical and Mechanical Tests Determination of Tensile Strength and Elongation, and the leather was placed in a hot oxygen aging oven, and after accelerated aging at 100℃ for 168h, the determination of elongation at break was carried out according to QB-T 2710-2005 Leather Physical and Mechanical Tests Determination of Tensile Strength and Elongation, to obtain the data of elongation at break before and after aging.

[0026] ; Referring to the above table, according to the comparison between Example 1-3 and Comparative Example 1-3, it can be seen that the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating has excellent anti-cracking performance and heat-oxygen aging resistance; According to the comparison between Example 1 and Comparative Example 1, it can be seen that the trousers tear of the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating is larger than that of the leather prepared by using benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating, indicating that the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating has excellent anti-cracking performance; According to the comparison between Example 1 and Comparative Example 2, it can be seen that the trousers tear of the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating is larger than that of the leather prepared by using phenolic hydroxyl isoquinoline and modified polyurethane emulsion as the coating, indicating that the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating has excellent anti-cracking performance; According to the comparison between Example 1 and Comparative Example 3, it can be seen that the trousers tear of the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating is larger than that of the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and polyurethane emulsion as the coating, indicating that the leather prepared by using phenolic hydroxyl isoquinoline, benzophenone-based p-phenylenediamine and modified polyurethane emulsion as the coating has excellent anti-cracking performance.

[0027] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0028] The above merely illustrates and describes the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace, as long as the modifications or supplements do not deviate from the present application or exceed the scope defined by the present application, and should belong to the protection scope of the present application.

Claims

1. An oxidation aging resistant, anti-cracking leather, characterized in that, The following components are included by weight parts: phenolic hydroxyl isoquinoline 3-5 parts, benzophenone-based p-phenylenediamine 5-10 parts and modified polyurethane emulsion 50-100 parts; The phenolic hydroxyl isoquinoline is prepared by the following steps: 2,6-dihydroxybenzaldehyde, anhydrous ethanol are added to a three-necked flask and stirred, 2-methoxyphenethylamine is added dropwise, the dropwise time is controlled, 3A molecular sieves are added and stirred, the molecular sieves are removed by filtration, ethanol is removed by vacuum filtration, a phosphoric acid solution is added, the reaction is carried out by heating and refluxing, deionized water is added, the pH is adjusted with a saturated sodium bicarbonate solution, stirring is carried out, organic phase is collected by extraction with ethyl acetate, anhydrous sodium sulfate is added for drying, oxalic acid is dissolved in ethyl acetate and added to the organic phase, dichloromethane is added to precipitate the solid, distilled water is added after filtration, stirring is carried out, the pH is adjusted with a saturated sodium bicarbonate solution, stirring is carried out, organic phase is collected by extraction with ethyl acetate, anhydrous sodium sulfate is added for drying, activated carbon is added, rotary evaporation is carried out after filtration, and the phenolic hydroxyl isoquinoline is obtained.

2. The oxidation aging resistant and cracking resistant leather according to claim 1, characterized in that, The amount ratio of the 2,6-dihydroxybenzaldehyde, anhydrous ethanol, 2-methoxyphenethylamine, 3A molecular sieves, phosphoric acid solution, deionized water, oxalic acid and ethyl acetate is 0.022-0.044 mol: 20-40 mL: 0.02-0.04 mol: 0.4-0.8 g: 20-40 mL: 50-100 mL: 1.8-3.6 g: 200-400 mL.

3. The oxidative aging resistant, anti-cracking leather according to claim 1, characterized in that, The mass fraction of the phosphoric acid solution is 85%.

4. The oxidation aging resistant and cracking resistant leather according to claim 1, characterized in that, The benzophenone-based p-phenylenediamine is prepared by the following steps: Step A1: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and epichlorohydrin are added to a three-necked flask, transferred to an oil bath, magnetically stirred, heated and reacted, cooled, washed with dichloromethane, evaporated to remove dichloromethane, and dried to obtain an intermediate product; Step A2: 2-hydroxybenzophenone and dichloromethane are added to a three-necked flask, transferred to an ice water bath, protected by nitrogen, triethylamine is added dropwise and stirred, the intermediate product is added and reacted, quenched with ice water, organic phase is collected by extraction, evaporated and rotary evaporated to remove dichloromethane, and separated by petroleum ether column chromatography to obtain the benzophenone-based p-phenylenediamine.

5. The oxidation aging resistant and cracking resistant leather according to claim 4, characterized in that, The amount ratio of the N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, epichlorohydrin and dichloromethane in step A1 is 0.01-0.02 mol: 0.012-0.024 mol: 50-100 mL.

6. The oxidative aging resistant, anti-cracking leather according to claim 4, characterized in that, The amount ratio of the 2-hydroxybenzophenone, dichloromethane, triethylamine and intermediate product in step A2 is 0.11-0.22 mol: 100-200 mL: 0.11-0.22 mol: 0.1-0.2 mol.

7. The oxidation aging resistant and cracking resistant leather according to claim 1, characterized in that, The modified polyurethane emulsion is prepared by the following steps: Polyethylene glycol is added to a three-mouth flask equipped with a stirrer, vacuum pump and glass plug, transferred to a heating device for warming, vacuum pump is opened, negative pressure, cooling is disconnected, nitrogen is introduced, isophorone diisocyanate is added dropwise, dibutyltin dilaurate is added, 2, 2-dihydroxymethyl propionic acid is added, 3, 3'-dimethyl benzidine is added, triethylamine is added, stirring is carried out under cooling, potassium chloride is added and stirring is carried out, deionized water is added to control the solid content of the emulsion, stirring is carried out, and a modified polyurethane emulsion is obtained.

8. The oxidation aging resistant and cracking resistant leather according to claim 7, characterized by, The amount ratio of the polyethylene glycol, isophorone diisocyanate, dibutyltin dilaurate, 2, 2-dihydroxymethyl propionic acid, 3, 3'-dimethyl benzidine, triethylamine and potassium chloride is 25-50g: 50-100mmol: 0.5-1mmol: 15-30mmol: 10-20mmol: 15-30mmol: 5-10mmol; and the type of the polyethylene glycol is PEG-1000.

9. A process for the production of an oxidation-ageing resistant, anti-cracking leather according to any one of claims 1 to 8, characterised in that, The method comprises the following steps: Step one: phenolic hydroxyl isoquinoline 3-5 parts, benzophenone p-phenylenediamine 5-10 parts and modified polyurethane emulsion 50-100 parts are weighed according to weight parts and prepared for use; Step two: phenolic hydroxyl isoquinoline, benzophenone p-phenylenediamine and modified polyurethane emulsion are mixed, coated on the leather, then heated at 100-140℃ for 1-6h, and an oxidation aging resistant and anti-cracking leather is obtained.

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