An anti-yellowing backing cloth with hot melt coating and a preparation method thereof

Abstract

This invention relates to the field of anti-yellowing technology, specifically to an anti-yellowing lining with a hot-melt coating and its preparation method. A finishing solution is prepared using composite carbon dots, an anti-yellowing agent, and a composite chitosan solution to finish the lining. Furfural and urea are selected as carbon and nitrogen sources, respectively, and nitrogen-doped furfural-based carbon dots are synthesized in a one-step hydrothermal process. An amino-terminated polyimidazolium salt antibacterial compound is then grafted onto the carbon dots to obtain the composite carbon dots. The amino-terminated polyimidazolium salt antibacterial compound is prepared from ethylenediamine, butyric acid, glyoxal, and formaldehyde using amine-aldehyde condensation as raw materials, resulting in a biocompatible amino-terminated halogen-free polyimidazolium salt antibacterial compound. A water-based polyurethane hot-melt adhesive is obtained by emulsifying with water using polybutylene adipate, toluene diisocyanate, and isophorone diisocyanate as the main monomers, polypropylene ether triol as the crosslinking monomer, 2,2-dimethylolpropionic acid and 4,4'-diaminodiphenyl disulfide as chain extenders, and the composite carbon dots as the capping agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anti-yellowing, and particularly relates to an anti-yellowing lining cloth with a hot melt coating and a preparation method thereof. BACKGROUND

[0002] With the development of people's living standards, the demand for functional lining cloth is increasing, especially in the fields of clothing and shoe materials. The lining cloth with a hot melt coating is generally compounded with the fabric through hot pressing adhesion. The traditional lining cloth with a hot melt coating is prone to yellowing when exposed to ultraviolet and humid heat for a long time, which affects the aesthetic appearance and service life. In addition, poor antibacterial properties also limit the application range of functional lining cloth.

[0003] At present, the improvement of the anti-yellowing performance of the lining cloth mainly depends on the finishing of organic ultraviolet absorbers such as benzotriazole or inorganic ultraviolet absorbers such as metal oxides. Most of the organic ultraviolet absorbers on the market are lipophilic compounds, which can be easily absorbed, penetrated through the skin and entered the human body through the food chain. Some studies have shown that some organic ultraviolet absorbers have potential harm to human health. Common inorganic ultraviolet absorbers such as titanium dioxide and zinc oxide nanoparticles have poor compatibility with textiles, and have problems such as insufficient durability and easy migration. In addition, conventional antibacterial agents, such as silver-based and quaternary ammonium salt-based antibacterial agents, have problems such as poor washability and biological toxicity. At the same time, the introduction of the hot melt coating in the functional lining cloth can improve the adhesion of the lining cloth, but the traditional solvent-based polyurethane hot melt adhesive also has the problem of easy environmental pollution. SUMMARY

[0004] The present application aims to provide an anti-yellowing lining cloth with a hot melt coating and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme:

[0006] A preparation method of an anti-yellowing lining cloth with a hot melt coating, comprising the following steps:

[0007] S1: mixing composite carbon dots, an anti-yellowing agent solution and a composite chitosan solution, and ultrasonic stirring to obtain an anti-yellowing finishing solution;

[0008] S2: performing two-dip-two-nip treatment on the lining cloth using the anti-yellowing finishing solution, and pre-drying to obtain a finished lining cloth;

[0009] S3: coating the surface of the finished lining cloth with a water-based polyurethane hot melt adhesive, and drying to obtain an anti-yellowing lining cloth with a hot melt coating.

[0010] Further, the working conditions of the two-dip-two-nip treatment are as follows: the dipping time is 50 s, and the rolling rate is 82%.

[0011] Further, the pre-baking working condition is: temperature is 100℃, and time is 100s.

[0012] Further, the use amount ratio of the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution is 1g:0.2g:(40-45)mL.

[0013] Further, the composition of the composite chitosan solution in mass fraction is: 100 parts of deionized water, 2.1-2.3 parts of citric acid, 0.4-0.6 parts of chitosan, 0.3-0.5 parts of triethanolamine, 0.5-1 parts of sodium hypophosphite, and 0.1 part of a penetrant.

[0014] Further, the mass ratio of the polybutylene adipate, the polypropylene ether triol, the toluene diisocyanate, the isophorone diisocyanate, the 2,2-dimethylol propionic acid, the 4,4'-diamino diphenyl disulfide and the composite carbon dots is 32:1:16:4:4:2:1.

[0015] Further, the preparation of the water-based polyurethane hot melt adhesive comprises the following steps:

[0016] The polybutylene adipate, the polypropylene ether triol, the toluene diisocyanate and the isophorone diisocyanate are mixed, dibutyltin dilaurate is added at 58-62℃, the temperature is raised to 73-75℃ and maintained for 50-60min, the 2,2-dimethylol propionic acid is added and maintained for 1-2h, the 4,4'-diamino diphenyl disulfide is added and maintained for 1-2h, the composite carbon dots and the acetone are added and maintained for 1-2h, the temperature is lowered, the ethylenediamine is added, rotary evaporation is performed, deionized water is added for emulsification, and the water-based polyurethane hot melt adhesive is obtained.

[0017] Further, the preparation of the composite carbon dots comprises the following steps:

[0018] 1) The furfural, the urea and the deionized water are mixed and transferred into a reaction kettle, the temperature is raised to 198-200℃ and maintained for 9-10h, the temperature is cooled to 18-25℃, centrifugation is performed, a water phase filter membrane with a pore size of 0.22μm is used for filtration, and dialysis is performed for 7d, so as to obtain nitrogen-doped furfuryl carbon dots;

[0019] 2) The ethylenediamine and the deionized water are mixed, butyric acid is added under ice bath at 0℃, the glyoxal and the formaldehyde are added, a sodium hydroxide solution is added to make the pH be 6.9-7.1, the oil bath is heated to 98-100℃ and maintained for 34-36h, the dialysis bag with a molecular weight cut-off of 1000Da is transferred into a dialysis bag for dialysis for 22-24h, and freeze-drying is performed, so as to obtain an amino-terminated polyimidazole salt antibacterial compound;

[0020] 3) The amino-terminated polyimidazole salt antibacterial compound and the toluene are mixed, the nitrogen-doped furfuryl carbon dots are added, water bath heating is performed to 85-95℃, glacial acetic acid is added, and the temperature is maintained for 3-4h, cooling, standing, and reduced-pressure filtration are performed, so as to obtain the composite carbon dots.

[0021] Further, the mass ratio of the amino-terminated polyimidazole salt antibacterial compound and the nitrogen-doped furfural carbon dots is 1.2:3.2.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The present application provides an anti-yellowing lining cloth with a hot melt coating and a preparation method thereof. Through process and component design, an anti-yellowing lining cloth with a green, environmentally friendly, antibacterial, and ultraviolet resistant self-repairing hot melt coating is prepared.

[0024] The lining cloth is finished with a finishing liquid prepared by using composite carbon dots as ultraviolet absorbers, combining environmentally friendly antioxidants as anti-yellowing agents, and composite chitosan solution. In the composite chitosan solution, triethanolamine is selected as a pH buffer, chitosan is selected as a biological antibacterial agent, citric acid and sodium hypophosphite are selected as acidifying agents and catalysts, and a penetrating agent is added. By controlling the ratio of each raw material, the lining cloth, composite carbon dots, chitosan, and polyphenolic environmentally friendly antioxidants form a complex crosslinked network when the lining cloth is finished with the finishing liquid, a multiple protection system is constructed, and the yellowing of the lining cloth under ultraviolet light, heat, and other environments is effectively inhibited, so that the lining cloth can maintain excellent antibacterial and ultraviolet resistance for a long time.

[0025] Low-toxicity, biocompatible, and environmentally friendly carbon dots are selected as ultraviolet-resistant agents, and furfural and urea are selected as carbon and nitrogen sources to synthesize nitrogen-doped furfural-based carbon dots in one step. To improve the uniformity of the dispersion of the nitrogen-doped furfural-based carbon dots in the finishing liquid, the aldehyde groups on the nitrogen-doped furfural-based carbon dots are grafted with amino-terminated polyimidazole salt antibacterial compounds to obtain composite carbon dots containing Schiff base structures, thereby greatly improving the ultraviolet resistance and antibacterial properties of the carbon dots. The introduction of multiple active sites on the surface of the carbon dots improves the bonding strength between the composite carbon dots and the lining cloth. The amino-terminated polyimidazole salt antibacterial compound is prepared from ethylenediamine, butyric acid, glyoxal, and formaldehyde based on amine-aldehyde polycondensation, and has good biocompatibility. The ultraviolet absorption and antibacterial properties of the Schiff base structure are further synergistically improved, achieving the effects of broad-spectrum antibacterial and ultraviolet resistance.

[0026] In order to solve the problem of environmental pollution of traditional solvent-based polyurethane hot melt adhesive, the water-based polyurethane hot melt adhesive is used to replace the traditional solvent-based hot melt adhesive, so that the VOC emission is reduced, and the green production requirement is met. The water-based polyurethane hot melt adhesive is obtained by using polybutylene glycol adipate, toluene diisocyanate and isophorone diisocyanate as main monomers, using polypropylene glycol ether triol as a crosslinking monomer, using 2,2-dimethylol propionic acid and 4,4'-diamino diphenyl disulfide as a chain extender, using composite carbon dots as a capping agent, and adding water to emulsify. The addition of the composite carbon dots not only enhances the antibacterial property and the ultraviolet resistance, but also converts the absorbed ultraviolet light into heat energy through the synergistic effect of the disulfide bond, so that the influence of ultraviolet radiation on the structure of the polyurethane is reduced. Meanwhile, the Schiff base structure on the composite carbon dots and the disulfide bond form a dynamic network, so that the coating has excellent self-repairing property, the durability of the yellowing resistance is improved, the effects of persistent antibacterial property and ultraviolet resistance are achieved, and the service life of the lining cloth is prolonged. DETAILED DESCRIPTION

[0027] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0028] In addition, the technical solutions of the various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it. When the combination of technical solutions appears to be contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

[0029] The technical solutions of the present application will be described in further detail below in combination with specific embodiments. It should be understood that the following embodiments are only used to explain the present application, and are not used to limit the present application.

[0030] Embodiment 1: A preparation method of an anti-yellowing lining cloth with a hot melt coating, comprising the following steps:

[0031] S1: mixing the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution, and ultrasonic stirring to obtain an anti-yellowing bacteria finishing liquid;

[0032] The dosage ratio of the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution is 1g:0.2g:45mL;

[0033] The composite chitosan solution comprises 100 parts of deionized water, 2.1 parts of citric acid, 0.4 parts of chitosan, 0.3 parts of triethanolamine, 0.5 parts of sodium hypophosphite and 0.1 part of a penetrant, in terms of mass fraction;

[0034] Preparation of the composite carbon dots includes the following steps:

[0035] 1) Mix 1 mL of furfural, 60 mg of urea, and 10 mL of deionized water, transfer into a reaction kettle, heat to 198℃ for 10 h, cool to 18℃, centrifuge, filter with a 0.22 μm water phase filter membrane, dialyze for 7 d, and obtain nitrogen-doped furfural carbon dots;

[0036] 2) Mix 1.4 g of ethylenediamine and 2 mL of deionized water, add 4 g of butyric acid under ice bath at 0℃, add 3.3 g of glyoxal, 1.7 g of formaldehyde, and sodium hydroxide solution to make the pH at 6.9, heat to 98℃ in an oil bath for 36 h, transfer into a dialysis bag with a molecular weight cut-off of 1000 Da for dialysis for 22 h, and freeze-dry to obtain an amino-terminated polyimidazole salt antibacterial compound;

[0037] 3) Mix 1.2 g of the amino-terminated polyimidazole salt antibacterial compound and 30 mL of toluene, add 3.2 g of the nitrogen-doped furfural carbon dots, heat to 85℃ in a water bath, add 0.3 mL of glacial acetic acid, and heat for 4 h, cool, stand, and filter under reduced pressure to obtain the composite carbon dots;

[0038] Preparation of the waterborne polyurethane hot melt adhesive includes the following steps:

[0039] Mix 32 g of polybutylene adipate glycol, 1 g of polypropylene ether triol, 16 g of toluene diisocyanate, and 4 g of isophorone diisocyanate, add 4 drops of dibutyltin dilaurate at 58℃, heat to 73℃ for 60 min, add 4 g of 2,2-dimethylol propionic acid and heat for 1 h, add 2 g of 4,4'-diamino diphenyl disulfide and heat for 1 h, add 1 g of the composite carbon dots and 5 mL of acetone, heat for 1 h, cool to 35℃, add 3 g of ethylenediamine, rotary evaporate, and emulsify with deionized water to obtain a waterborne polyurethane hot melt adhesive with a solid content of 40%;

[0040] S2: Perform two-dip-two-nip treatment on the backing cloth with the anti-yellowing and antibacterial finishing liquid, pre-dry, and obtain the finished backing cloth;

[0041] The working conditions for the two-dip-two-nip treatment are: dip time of 50 s and nip rate of 80%; and the working conditions for the pre-drying are: temperature of 100℃ and time of 100 s;

[0042] S3: Coat the waterborne polyurethane hot melt adhesive on the surface of the finished backing cloth, dry, and obtain an anti-yellowing backing cloth with a hot melt coating.

[0043] Example 2: A method for preparing an anti-yellowing backing cloth with a hot melt coating, including the following steps:

[0044] S1: Mix the composite carbon dots, the anti-yellowing agent solution, and the composite chitosan solution, and ultrasonically stir to obtain an anti-yellowing and antibacterial finishing liquid;

[0045] The use amount ratio of the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution is 1g:0.2g:43mL;

[0046] The composition of the composite chitosan solution is: 100 parts of deionized water, 2.2 parts of citric acid, 0.5 parts of chitosan, 0.4 parts of triethanolamine, 0.6 parts of sodium hypophosphite, and 0.1 parts of penetrant, in terms of mass fraction;

[0047] The preparation of the composite carbon dots comprises the following steps:

[0048] 1) 1mL of furfural, 60mg of urea and 10mL of deionized water are mixed and transferred into a reaction kettle, the temperature is raised to 199℃ and kept for 9.5h, and then cooled to 20℃, centrifuged, filtered with a water phase filter membrane with a pore size of 0.22μm, and dialyzed for 7d to obtain nitrogen-doped furfural carbon dots;

[0049] 2) 1.4g of ethylenediamine and 2mL of deionized water are mixed, 4g of butyric acid is added under ice bath at 0℃, 3.3g of glyoxal and 1.7g of formaldehyde are added, sodium hydroxide solution is added to make the pH at 7, the oil bath is heated to 99℃ and kept for 35h, and then transferred into a dialysis bag with a molecular weight cut-off of 1000Da for dialysis for 23h, and then freeze-dried to obtain an amino-terminated polyimidazole salt antibacterial compound;

[0050] 3) 1.2g of the amino-terminated polyimidazole salt antibacterial compound and 30mL of toluene are mixed, 3.2g of the nitrogen-doped furfural carbon dots are added, heated to 90℃ in a water bath, 0.3mL of glacial acetic acid is added, kept for 3.5h, cooled, left standing, and filtered under reduced pressure to obtain the composite carbon dots;

[0051] The preparation of the water-based polyurethane hot melt adhesive comprises the following steps:

[0052] 32g of polybutylene adipate, 1g of polypropylene ether triol, 16g of toluene diisocyanate and 4g of isophorone diisocyanate are mixed, 4 drops of dibutyltin dilaurate are added at 60℃, the temperature is raised to 74℃ and kept for 55min, 4g of 2,2-dimethylol propionic acid is added and kept for 1.5h, 2g of 4,4'-diamino diphenyl disulfide is added and kept for 1.5h, 1g of the composite carbon dots and 5mL of acetone are added, kept for 1.5h, the temperature is lowered to 35℃, 3g of ethylenediamine is added, rotary evaporated, and emulsified with deionized water to obtain a water-based polyurethane hot melt adhesive with a solid content of 40%;

[0053] S2: the backing cloth is treated by two-dip-two-roll with the anti-yellowing finishing liquid, and pre-dried to obtain the finished backing cloth;

[0054] The working conditions of the two-dip-two-roll treatment are: the dipping time is 50s and the roll-up rate is 80%; the working conditions of the pre-drying are: the temperature is 100℃ and the time is 100s;

[0055] S3: coating the surface of the prepared lining cloth with water-based polyurethane hot melt adhesive, drying to obtain an anti-yellowing lining cloth with a hot melt coating.

[0056] Embodiment 3: a preparation method of an anti-yellowing lining cloth with a hot melt coating, comprising the following steps:

[0057] S1: mixing the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution, and ultrasonic stirring to obtain an anti-yellowing bacteria finishing liquid;

[0058] The amount ratio of the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution is 1g:0.2g:40mL;

[0059] The composition of the composite chitosan solution in terms of mass fraction is: 100 parts of deionized water, 2.3 parts of citric acid, 0.6 parts of chitosan, 0.5 parts of triethanolamine, 1 part of sodium hypophosphite, and 0.1 part of a penetrant;

[0060] The preparation of the composite carbon dots comprises the following steps:

[0061] 1) mixing 1mL of furfural, 60mg of urea and 10mL of deionized water, transferring into a reaction kettle, heating to 200℃ for 9h, cooling to 25℃, centrifuging, filtering with a water phase filter membrane of 0.22μm, and dialyzing for 7d to obtain nitrogen-doped furfural carbon dots;

[0062] 2) mixing 1.4g of ethylenediamine and 2mL of deionized water, adding 4g of butyric acid under ice bath at 0℃, adding 3.3g of glyoxal and 1.7g of formaldehyde, adding sodium hydroxide solution to make the pH at 7.1, heating to 100℃ in an oil bath for 34h, transferring into a dialysis bag with a molecular weight cut-off of 1000Da for dialysis for 24h, and freeze-drying to obtain an amino-terminated polyimidazole salt antibacterial compound;

[0063] 3) mixing 1.2g of the amino-terminated polyimidazole salt antibacterial compound and 30mL of toluene, adding 3.2g of the nitrogen-doped furfural carbon dots, heating to 95℃ in a water bath, adding 0.3mL of glacial acetic acid, keeping for 3h, cooling, standing, and filtering under reduced pressure to obtain the composite carbon dots;

[0064] The preparation of the water-based polyurethane hot melt adhesive comprises the following steps:

[0065] 32 g polybutylene adipate, 1 g polypropylene ether triol, 16 g toluene diisocyanate, 4 g isophorone diisocyanate are mixed, 4 drops of dibutyltin dilaurate is added at 62℃, the temperature is raised to 75℃ for 50 min, 4 g of 2,2-dimethylol propionic acid is added for 2 h, 2 g of 4,4'-diamino diphenyl disulfide is added for 2 h, 1 g of composite carbon dots, 5 mL of acetone is added, and the temperature is kept for 2 h, the temperature is lowered to 35℃, 3 g of ethylenediamine is added, rotary evaporation, emulsified with deionized water, to obtain a water-based polyurethane hot melt adhesive with a solid content of 40%;

[0066] S2: The lining cloth is treated by two-dip-two-pad with the anti-yellowing finishing liquid, and pre-dried to obtain the finished lining cloth;

[0067] The working conditions of the two-dip-two-pad treatment are: the dipping time is 50 s, and the rolling rate is 80%; the working conditions of the pre-drying are: the temperature is 100℃, and the time is 100 s;

[0068] S3: The water-based polyurethane hot melt adhesive is coated on the surface of the finished lining cloth, and dried to obtain an anti-yellowing lining cloth with a hot melt coating.

[0069] Comparative Example 1: Using Example 3 as a control group, replace the composite carbon dots with nitrogen-doped furfural carbon dots, and other procedures are normal;

[0070] A preparation method of an anti-yellowing lining cloth with a hot melt coating, comprising the following steps:

[0071] S1: The composite carbon dots, the anti-yellowing agent solution, and the composite chitosan solution are mixed and ultrasonically stirred to obtain an anti-yellowing finishing liquid;

[0072] The amount ratio of the composite carbon dots, the anti-yellowing agent solution, and the composite chitosan solution is 1g:0.2g:40mL;

[0073] The composition of the composite chitosan solution is: 100 parts of deionized water, 2.3 parts of citric acid, 0.6 parts of chitosan, 0.5 parts of triethanolamine, 1 part of sodium hypophosphite, and 0.1 part of a penetrant, by mass fraction;

[0074] The preparation of the composite carbon dots comprises the following steps:

[0075] 1) 1 mL of furfural, 60 mg of urea, and 10 mL of deionized water are mixed and transferred into a reaction kettle, the temperature is raised to 200℃ for 9 h, the temperature is cooled to 25℃, centrifuged, filtered with a 0.22 μm water phase filter, and dialyzed for 7 days to obtain nitrogen-doped furfural carbon dots;

[0076] The preparation of the water-based polyurethane hot melt adhesive comprises the following steps:

[0077] 32 g of polybutylene adipate, 1 g of polypropylene ether triol, 16 g of toluene diisocyanate, 4 g of isophorone diisocyanate are mixed, 4 drops of dibutyl tin dilaurate are added at 62℃, the temperature is raised to 75℃ for 50 min, 4 g of 2,2-dimethylol propionic acid is added and kept for 2 h, 2 g of 4,4'-diamino diphenyl disulfide is added and kept for 2 h, 1 g of composite carbon dots, 5 mL of acetone are added, kept for 2 h, the temperature is lowered to 35℃, 3 g of ethylenediamine is added, rotary evaporation, emulsified with deionized water, to obtain a water-based polyurethane hot melt adhesive with a solid content of 40%;

[0078] S2: The lining cloth is treated by two-dip-two-roll with the anti-yellowing finishing liquid, pre-dried, to obtain the finished lining cloth;

[0079] The working conditions of the two-dip-two-roll treatment are: the dipping time is 50 s, and the roll-up rate is 80%; the working conditions of the pre-drying are: the temperature is 100℃, and the time is 100 s;

[0080] S3: The water-based polyurethane hot melt adhesive is coated on the surface of the finished lining cloth, dried, to obtain an anti-yellowing lining cloth with a hot melt coating.

[0081] Comparative Example 2: The preparation of the water-based polyurethane hot melt adhesive does not add 4,4'-diamino diphenyl disulfide, and other procedures are normal, taking Example 3 as the control group;

[0082] A preparation method of an anti-yellowing lining cloth with a hot melt coating, comprising the following steps:

[0083] S1: The composite carbon dots, the anti-yellowing agent solution, and the composite chitosan solution are mixed and ultrasonically stirred to obtain an anti-yellowing finishing liquid;

[0084] The dosage ratio of the composite carbon dots, the anti-yellowing agent solution, and the composite chitosan solution is 1 g:0.2 g:40 mL;

[0085] The composition of the composite chitosan solution is: 100 parts of deionized water, 2.3 parts of citric acid, 0.6 parts of chitosan, 0.5 parts of triethanolamine, 1 part of sodium hypophosphite, and 0.1 part of a penetrant, by mass fraction;

[0086] The preparation of the composite carbon dots comprises the following steps:

[0087] 1) 1 mL of furfural, 60 mg of urea, and 10 mL of deionized water are mixed and transferred into a reaction kettle, the temperature is raised to 200℃ and kept for 9 h, the temperature is cooled to 25℃, centrifuged, filtered with a 0.22 μm water phase filter, dialyzed for 7 d, to obtain nitrogen-doped furfuryl carbon dots;

[0088] 2) Mix 1.4 g ethylenediamine, 2 mL deionized water, add 4 g butyric acid under ice bath at 0℃, add 3.3 g glyoxal, 1.7 g formaldehyde, add sodium hydroxide solution to make pH at 7.1, heat to 100℃ in oil bath for 34 h, transfer to dialysis bag with molecular weight cut-off at 1000 Da, dialysis for 24 h, freeze-drying to obtain amino-terminated polyimidazole salt antibacterial compound;

[0089] 3) Mix 1.2 g amino-terminated polyimidazole salt antibacterial compound, 30 mL toluene, add 3.2 g nitrogen-doped furfuryl alcohol carbon dots, heat to 95℃ in water bath, add 0.3 mL glacial acetic acid, heat for 3 h, cool, stand, filter under reduced pressure to obtain composite carbon dots;

[0090] The preparation of the water-based polyurethane hot melt adhesive comprises the following steps:

[0091] Mix 32 g polybutylene adipate, 1 g polypropylene ether triol, 16 g toluene diisocyanate, 4 g isophorone diisocyanate, add 4 drops dibutyltin dilaurate at 62℃, heat to 75℃ for 50 min, add 4 g 2,2-dimethylol propionic acid and heat for 2 h, add 1 g composite carbon dots and 5 mL acetone, heat for 2 h, cool to 35℃, add 3 g ethylenediamine, rotary evaporation, emulsify with deionized water to obtain a water-based polyurethane hot melt adhesive with a solid content of 40%;

[0092] S2: Dip and pad the backing cloth with the anti-yellowing finishing liquid twice, pre-dry to obtain the finished backing cloth;

[0093] The working conditions for the dip and pad treatment are: dipping time of 50 s and pad rate of 80%; the working conditions for the pre-drying are: temperature of 100℃ and time of 100 s;

[0094] S3: Coat the water-based polyurethane hot melt adhesive on the surface of the finished backing cloth, dry to obtain an anti-yellowing backing cloth with a hot melt coating.

[0095] In the examples and comparative examples, 2 μm thick water-based polyurethane hot melt adhesive is coated on the surface of the finished backing cloth.

[0096] In the examples and comparative examples, the anti-yellowing agent solution is obtained by compounding the anti-yellowing agent with ethanol at a mass ratio of 1:1.

[0097] The sources of the raw materials used (only as an example) are as follows:

[0098] Anti-yellowing agent (environment-friendly antioxidant DTBHQ) 007: Parsch Medical Technology (Shanghai) Co., Ltd.; Penetrating agent SF: Linyi Guoli Chemical Co., Ltd.; Polypropylene oxide ether triol PPO (Mn is 500): Sinopec Tianjin Branch; Lining cloth (PP, AB303): Zhejiang Runjiang New Material Technology Co., Ltd.; Citric acid C434175, chitosan C299272, furfural F100546, urea U111897, ethylenediamine E112132, butyric acid B431361, glyoxal G661982, formaldehyde F111939, polybutylene adipate B302960, toluene diisocyanate T135411, isophorone diisocyanate I109582, dibutyltin dilaurate D100274, 2,2-dimethylol propionic acid B104539, 4,4'-diamino diphenyl disulfide A101817: Aladdin reagent; triethanolamine, sodium hypophosphite, toluene, ethanol, acetic acid, acetone, analytical pure, commercially available.

[0099] Performance test: the lining cloth prepared in the examples and comparative examples is tested:

[0100] Antibacterial property: staphylococcus aureus is used as test strain, and a plate method is used for testing, and the water washing resistance of the sample is tested according to the accelerated method for color fastness to washing in household and commercial washing, 5 min each time, and the antibacterial rate is tested after 20 times of water washing and drying;

[0101] Anti-yellowing grade: the water washing resistance of the sample is tested according to the accelerated method for color fastness to washing in household and commercial washing, 5 min each time, and the anti-yellowing grade is tested after 20 times of water washing, and the test is carried out according to GB / T1766-2008, the sample is cut into a 50mm square, the working conditions of the anti-yellowing experiment box are as follows: the temperature is 60 DEG C, the ultraviolet lamp is 300W, the light source distance is 25cm, the illumination time is 12h, the general color difference meter is used for testing the color difference of the sample, the color difference value is calculated, 0 is the best, indicating no discoloration;

[0102] Self-repairing property: a scratch with a depth of 1um, a length of 0.5mm and a width of 1um is drawn on the surface of the coating of the sample, the scratch length is observed under an electron microscope after 24h of incubation at 70 DEG C, and the self-repairing rate is calculated as (L 初始划 The obtained results are shown in Table 1;

[0103] Table 1

[0104] Antibacterial property (%) Resistance to yellowing grade Self-healing rate (%) Example 1 99.8 0 grade 99.9 Example 2 99.9 0 grade 99.9 Example 3 99.9 0 grade 100 Comparative Example 1 91.1 1 grade 92.4 Comparative Example 2 98.4 1 grade 95.3

[0105] The application provides an anti-yellowing lining cloth with a hot melt coating and a preparation method thereof, and through process and component design, the anti-yellowing lining cloth with a green, environment-friendly, antibacterial, anti-ultraviolet and self-repairing hot melt coating is prepared.

[0106] Comparing Example 3 with Comparative Example 1, it can be seen that the carbon dots with easy synthesis, low toxicity, good biocompatibility and environmental friendliness are selected as the anti-ultraviolet agent, furfural and urea are selected as the carbon source and nitrogen source, and nitrogen-doped furfuryl carbon dots are synthesized by one-step hydrothermal synthesis, in order to improve the uniformity of the dispersion of the nitrogen-doped furfuryl carbon dots in the finishing liquid, the aldehyde group on the nitrogen-doped furfuryl carbon dots is grafted with the amino group on the amino-terminated polyimidazole salt antibacterial compound to obtain a composite carbon dot containing a Schiff base structure, thereby greatly improving the anti-ultraviolet property and antibacterial property of the carbon dots, and the introduction of the surface active sites improves the bonding strength of the composite carbon dots and the lining cloth; the amino-terminated polyimidazole salt antibacterial compound is prepared from ethylenediamine, butyric acid, glyoxal and formaldehyde based on amine-aldehyde polycondensation, and has good biocompatibility, the ultraviolet absorption property and antibacterial property of the Schiff base structure further synergistically improve the ultraviolet absorption property and antibacterial property of the composite carbon dots, and the effects of broad-spectrum antibacterial and anti-ultraviolet are achieved.

[0107] Comparing Example 3 with Comparative Example 2, it can be seen that, in order to solve the problem of environmental pollution caused by the traditional solvent-based polyurethane hot melt adhesive, the water-based polyurethane hot melt adhesive is used to replace the traditional solvent-based hot melt adhesive, the VOC emission is reduced, and the green production requirement is met, polybutylene adipate glycol, toluene diisocyanate and isophorone diisocyanate are used as main monomers, polypropylene ether triol is used as a crosslinking monomer, 2,2-dimethylol propionic acid and 4,4'-diamino diphenyl disulfide are used as chain extenders, and the composite carbon dots are used as a capping agent, and water is added and emulsified to obtain the water-based polyurethane hot melt adhesive, the addition of the composite carbon dots not only enhances the antibacterial property and anti-ultraviolet property, but also converts the absorbed ultraviolet light into heat energy through the synergistic effect of the composite carbon dots and the disulfide bond, thereby reducing the influence of ultraviolet radiation on the structure of the polyurethane, the Schiff base structure on the composite carbon dots and the disulfide bond form a dynamic network, excellent self-repairing property is obtained for the coating, the durability of the yellowing resistance of the coating is improved, the effects of long-lasting antibacterial and anti-ultraviolet are achieved, and the service life of the lining cloth is prolonged.

[0108] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made according to the inventive concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A process for the production of an anti-yellowing backing cloth having a hot melt coating, characterized in that, The method comprises the following steps: S1: mixing the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution, ultrasonic stirring to obtain an anti-yellowing bacteria finishing liquid; S2: using the anti-yellowing bacteria finishing liquid to perform two-dip-two-roll treatment on the lining cloth, pre-drying to obtain the finished lining cloth; S3: coating the water-based polyurethane hot melt adhesive on the surface of the finished lining cloth, drying to obtain an anti-yellowing lining cloth with a hot melt coating layer. The preparation of the composite carbon dots comprises the following steps: 1) mixing furfural, urea and deionized water, transferring into a reaction kettle, heating to 198-200 DEG C and keeping for 9-10 h, cooling to 18-25 DEG C, centrifuging, filtering and dialyzing to obtain nitrogen-doped furfural carbon dots; 2) mixing ethylenediamine and deionized water, adding butyric acid under 0 DEG C ice bath, adding glyoxal and formaldehyde, adding sodium hydroxide solution to make pH at 6.9-7.1, oil bath heating to 98-100 DEG C and keeping for 34-36 h, dialyzing for 22-24 h and freeze-drying to obtain an amino-terminated polyimidazole salt antibacterial compound; 3) mixing the amino-terminated polyimidazole salt antibacterial compound and toluene under nitrogen atmosphere, adding nitrogen-doped furfural carbon dots, water bath heating to 85-95 DEG C, adding glacial acetic acid, keeping for 3-4 h, cooling, standing and reducing pressure filtering to obtain the composite carbon dots; The preparation of the water-based polyurethane hot melt adhesive comprises the following steps: Mixing polybutylene adipate, polypropylene ether triol, toluene diisocyanate and isophorone diisocyanate, adding dibutyltin dilaurate at 58-62 DEG C, heating to 73-75 DEG C and keeping for 50-60 min, adding 2,2-dimethylol propionic acid and keeping for 1-2 h, adding 4,4'-diamino diphenyl disulfide and keeping for 1-2 h, adding the composite carbon dots and acetone and keeping for 1-2 h, cooling, adding ethylenediamine, rotary evaporation, adding deionized water for emulsification to obtain the water-based polyurethane hot melt adhesive.

2. The process for preparing an anti-yellowing release paper having a hot melt coating according to claim 1, wherein The working conditions of the two-dip-two-roll treatment are that the dipping time is 50 s and the rolling rate is 82%.

3. The process for preparing an anti-yellowing release paper having a hot melt coating according to claim 1, wherein The working conditions of the pre-drying are that the temperature is 100 DEG C and the time is 100 s.

4. The process for preparing an anti-yellowing release paper having a hot melt coating according to claim 1, wherein In the anti-yellowing bacteria finishing liquid, the mass ratio of the composite carbon dots, the anti-yellowing agent solution and the composite chitosan solution is 1g:0.2g:(40-45)mL.

5. The process for preparing the anti-yellowing release paper with hot melt coating according to claim 1, characterized in that, The composition of the composite chitosan solution is, in mass parts, 100 parts of deionized water, 2.1-2.3 parts of citric acid, 0.4-0.6 parts of chitosan, 0.3-0.5 parts of triethanolamine, 0.5-1 parts of sodium hypophosphite and 0.1 part of a penetrating agent.

6. The process for preparing an anti-yellowing release paper having a hot melt coating according to claim 1, wherein In the preparation of the water-based polyurethane hot melt adhesive, the mass ratio of the polybutylene adipate, the polypropylene ether triol, the toluene diisocyanate, the isophorone diisocyanate, the 2,2-dimethylol propionic acid, the 4,4'-diamino diphenyl disulfide and the composite carbon dots is 32:1:16:4:4:2:

1.

7. The process for preparing an anti-yellowing release paper having a hot melt coating according to claim 1, wherein In the preparation of the composite carbon dots, the mass ratio of the amino-terminated polyimidazole salt antibacterial compound and the nitrogen-doped furfural carbon dots is 1.2:3.

2.

8. An anti-yellowing backing cloth having a hot melt coating, characterized in that, Prepared by the preparation method in any one of claims 1-7.