Photocatalytic formaldehyde removal fabric and preparation method thereof

Abstract

This application discloses a photocatalytic formaldehyde-removing fabric and a preparation method thereof. The formaldehyde-removing fabric comprises a fabric and a photocatalytic coating supported on the fabric. The raw materials of the photocatalytic coating include, by weight, 10 to 15 parts of an aqueous polyurethane emulsion; 5 to 10 parts of an adhesion promoter; and 10 to 20 parts of a modified photocatalyst. The modified photocatalyst is prepared by reacting raw materials including silver-doped titanium dioxide and amino-polyethylene glycol-thiol groups, with the mass ratio of the silver-doped titanium dioxide to amino-polyethylene glycol-thiol groups being 1:(3 to 6). The photocatalytic formaldehyde-removing fabric of this application can improve the adhesion of the photocatalyst while maintaining its softness, thereby ensuring the durability of the fabric's formaldehyde-removing effect.

Description

Technical Field

[0001] The present application relates to the field of functional fabrics, and in particular to a photocatalytic formaldehyde-removing fabric and a preparation method thereof. Background Art

[0002] Formaldehyde produced by home renovations poses a serious health hazard to human health. Long-term exposure to excessive formaldehyde levels can easily lead to headaches, respiratory problems, and even cancer. Currently, the most commonly used formaldehyde removal methods are still physical methods like ventilation and activated carbon adsorption. However, these methods are inefficient and fail to meet public demand for efficient formaldehyde removal.

[0003] Photocatalysts are a class of semiconductor materials with photocatalytic properties, typified by nano-titanium dioxide. Under illumination, when photon energy exceeds the semiconductor's absorption threshold, valence band electrons undergo inter-band transitions, generating photogenerated electrons and holes. Dissolved oxygen adsorbed on the photocatalyst surface then captures electrons to form superoxide anions, while holes oxidize hydroxide ions and water adsorbed on the catalyst surface into hydroxyl radicals. Superoxide anions and hydroxyl radicals possess strong oxidizing properties, decomposing formaldehyde into CO2 and H2O. Their efficient and thorough treatment of formaldehyde, along with their non-toxic and harmless nature, has led to their widespread application.

[0004] Applying a photocatalyst coating to the surface of curtain fabric can effectively degrade indoor formaldehyde using light, improving formaldehyde removal efficiency. However, the photocatalyst in the coating is prone to falling off during use, affecting the coating's durability. Summary of the Invention

[0005] In a first aspect, the present application provides a photocatalytic formaldehyde removal fabric, comprising a fabric and a photocatalytic coating supported on the fabric; the raw materials of the photocatalytic coating include, by weight:

[0006] 10-15 parts of water-based polyurethane emulsion;

[0007] 5-10 parts of adhesion promoter;

[0008] 10-20 parts of modified photocatalyst;

[0009] The modified photocatalyst is prepared by reacting raw materials including silver-doped titanium dioxide and amino-polyethylene glycol-mercapto group, and the mass ratio of the silver-doped titanium dioxide to the amino-polyethylene glycol-mercapto group is 1:(3-6).

[0010] The silver-doped titanium dioxide used in this application has a composite semiconductor structure. Doping with silver ions can improve the band gap and light absorption range of titanium dioxide, thereby improving photocatalytic efficiency. At the same time, silver ions can synergize with nano-titanium dioxide to effectively improve the antibacterial and antimicrobial properties of the fabric. Amino-polyethylene glycol-thiol is a polyethylene glycol molecule terminated with amino groups and thiol groups. Its thiol end coordinates and complexes with the silver ions in the silver-doped titanium dioxide. Its amino end can have good compatibility with aqueous polyurethane emulsions, promoting the dispersion of silver-doped titanium dioxide particles. In addition, the active groups in the aqueous polyurethane emulsion can form hydrogen bonds with the amino end, improving the adhesion of the photocatalyst and reducing the probability of shedding.

[0011] Preferably, the aqueous polyurethane emulsion is a self-crosslinking aqueous polyurethane.

[0012] Preferably, the adhesion promoter is a carboxyl-terminated hyperbranched polyester.

[0013] Typically, increasing the amount of adhesive is necessary to improve adhesion, but this inevitably affects the degradation of the photocatalyst. Furthermore, increasing the coating thickness reduces the fabric's softness, affecting fabric processing and use, and can easily cause the coating to crack. To address this issue, the present invention employs a carboxyl-terminated hyperbranched polyester, which significantly improves the adhesion of silver-doped titanium dioxide while also enhancing the toughness of the finished fabric.

[0014] Specifically, the carboxyl-terminated hyperbranched polyester has a spherical structure and is rich in carboxyl groups on its surface. These groups can undergo amidation reactions with the amino groups in the waterborne polyurethane and the amino groups introduced on the surface of the silver-doped titanium dioxide, forming a strong chemical bond between the two and significantly improving the adhesion of the silver-doped titanium dioxide. More importantly, the molecular chains of the carboxyl-terminated hyperbranched polyester are not easily entangled, and the spherical structure has a cavity structure. After cross-linking with the waterborne polyurethane emulsion and silver-doped titanium dioxide, free volume exists near the cross-linking points, which can improve the flexibility of the coating, thereby improving the softness of the fabric and reducing the probability of cracking and peeling of the coating.

[0015] Preferably, the raw materials of the photocatalytic coating further include 2 to 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

[0016] 1-Ethyl-(3-dimethylaminopropyl)carbodiimide can activate the carboxyl groups of the carboxyl-terminated hyperbranched polyester, promote the occurrence of chemical cross-linking reaction, and help improve the adhesion of silver-doped titanium dioxide.

[0017] Preferably, the D50 particle size of the silver-doped titanium dioxide is 1 to 100 nm.

[0018] Preferably, the molecular weight of the polyethylene glycol in the amino-polyethylene glycol-thiol group is 800-2000.

[0019] Preferably, the silver-doped titanium dioxide is prepared by a sol-gel method, and its raw materials include, by mass: 10 parts of butyl titanate

[0020] 1-3 parts silver nitrate solution

[0021] 30-40 parts of ethanol

[0022] Water 2-4

[0023] Anhydrous acetic acid 5-10.

[0024] Preferably, the raw materials of silver-doped titanium dioxide further include a modifier, and the modifier includes 2 to 3 parts of epoxy silane coupling agent and 0.5 to 1 part of sodium sulfamate.

[0025] Preferably, the preparation method of silver-doped titanium dioxide comprises the following steps:

[0026] Preparation of raw materials: Take an appropriate amount of ethanol in a preparation tank, add butyl titanate dropwise under stirring, add silver nitrate solution after the addition is complete, and mix well to obtain a precursor solution; mix anhydrous acetic acid, water and the remaining ethanol to obtain a coagulation solution;

[0027] Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react to obtain a gel;

[0028] Calcination: The gel is dried and then ground into powder, and the powder is calcined at 400-500° C. for 2-4 hours to obtain an intermediate powder; a crude silver-doped titanium dioxide product is obtained;

[0029] Surface modification: The crude silver-doped titanium dioxide product was dispersed in ethanol, an epoxy silane coupling agent was added, and sodium aminosulfonate was added after stirring for reaction, and the reaction was continued to obtain silver-doped titanium dioxide.

[0030] The present application uses epoxy silane coupling agent and sodium aminosulfonate to modify the surface of silver-doped titanium dioxide, which is beneficial to promote the dispersion of doped titanium dioxide nanoparticles, fully inhibit the agglomeration between silver-doped titanium dioxide ions, and obtain a coating with uniform distribution of photocatalysts, which is beneficial to improve the methanol removal rate and reduce the shedding rate. Specifically, the epoxy silane coupling agent reacts with silver-doped titanium dioxide to introduce epoxy groups into the surface of the nanoparticles, and then reacts with sodium aminosulfonate to introduce negatively charged sulfonic acid groups on its surface. The steric hindrance of the epoxy silane chain and the electrostatic effect of the sulfonic acid group cooperate to effectively inhibit the agglomeration between silver-doped titanium dioxide particles.

[0031] Preferably, the raw materials of the photocatalytic coating further include 5 to 10 parts of chitosan, and the deacetylation degree of the chitosan is not less than 85%.

[0032] The chitosan, with a deacetylation degree of at least 85%, exhibits excellent water solubility and compatibility with aqueous polyurethane emulsions, providing excellent film-forming properties that enhance the coating's antibacterial and antimicrobial effects. Furthermore, chitosan exhibits positive charge in the system, enhancing the adhesion of the negatively charged silver-doped titanium dioxide and reducing its potential for shedding.

[0033] In a second aspect, the present application provides a method for preparing a photocatalytic formaldehyde-removing fabric, comprising the following steps:

[0034] Padding finishing: Add the raw materials of the photocatalytic coating into water to prepare a finishing agent, and immerse the fabric in the finishing agent for two-dipping and two-padding treatment;

[0035] Drying and shaping: the rolled fabric is dried and shaped to obtain photocatalytic formaldehyde-removing fabric.

[0036] Preferably, in the finishing agent, the ratio of the raw material of the photocatalytic coating to water is 1:2-5.

[0037] Preferably, the bath ratio during fabric immersion is 3 to 5:1, and the immersion time is 0.5 to 1.5 hours.

[0038] It should be noted that the two-dip and two-roll process refers to the dipping-rolling process being performed twice in succession to increase the loading rate of the photocatalyst on the fabric surface.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. This application uses water-based polyurethane emulsion as an adhesive, silver-doped titanium dioxide grafted with amino-polyethylene glycol-thiol as a photocatalyst, and terminal carboxyl hyperbranched polyester as an adhesion promoter. It can significantly improve the adhesion of silver-doped titanium dioxide on the coating, ensure the toughness of the coating and the softness of the fabric, and help reduce the probability of silver-doped titanium dioxide peeling off and improve the durability of the photocatalytic formaldehyde removal effect.

[0041] 2. The surface of silver-doped titanium dioxide is modified by epoxy silane coupling agent and sodium aminosulfonate, which can introduce silane chains and sulfonic acid groups on the silver-doped titanium dioxide particles, thereby generating steric hindrance and electrostatic effects, effectively inhibiting the agglomeration of particles, promoting the dispersion of photocatalysts and the performance of formaldehyde removal. DETAILED DESCRIPTION

[0042] Preparation example of photocatalyst

[0043] Preparation Example 1

[0044] A photocatalyst is prepared according to the following steps:

[0045] Raw material preparation: 2 kg of ethanol is placed in a preparation tank, and 1 kg of tetrabutyl titanate is added dropwise while stirring. After the addition is complete, 0.2 kg of 1 mol / L silver nitrate solution is added and mixed evenly to obtain a precursor solution; 0.6 kg of anhydrous acetic acid, 0.2 kg of water, and 1 kg of ethanol are mixed evenly to obtain a coagulation solution.

[0046] Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react for 30 minutes to obtain a gel.

[0047] Calcination: The gel was aged and air-dried for 5 hours, ground into powder, and the powder was calcined at 450° C. for 3 hours to obtain a crude silver-doped titanium dioxide product.

[0048] Surface modification: The crude silver-doped titanium dioxide obtained by calcination was dispersed in ethanol, 0.2 kg of KH-560 was added, and after stirring for 20 minutes, 0.06 kg of sodium aminosulfonate was added and the reaction was continued for 30 minutes. The product was filtered, washed with water, and dried at 50°C to obtain silver-doped titanium dioxide.

[0049] Amino grafting: Take 0.1 kg of surface-modified silver-doped titanium dioxide and disperse it in 0.5 L of water. Heat it to 50°C, then add 0.4 kg of amino-polyethylene glycol-thiol (polyethylene glycol molecular weight is 1000), stir and react for 30 minutes, filter and dry to obtain amino-grafted silver-doped titanium dioxide, which is the photocatalyst.

[0050] Preparation Example 2

[0051] A photocatalyst is prepared according to the following steps:

[0052] Raw material preparation: 2.5 kg of ethanol was placed in a preparation tank, and 1 kg of tetrabutyl titanate was added dropwise while stirring. After the addition was complete, 0.3 kg of 1 mol / L silver nitrate solution was added and mixed evenly to obtain a precursor solution; 0.9 kg of anhydrous acetic acid, 0.35 kg of water, and 1.2 kg of ethanol were mixed evenly to obtain a coagulation solution;

[0053] Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react for 30 minutes to obtain a gel.

[0054] Calcination: The gel was aged and air-dried for 5 hours, ground into powder, and the powder was calcined at 480° C. for 2 hours to obtain a crude silver-doped titanium dioxide product.

[0055] Surface modification: The crude silver-doped titanium dioxide obtained by calcination was dispersed in ethanol, 0.2 kg of KH-560 was added, and after stirring for 20 minutes, 0.08 kg of sodium aminosulfonate was added and the reaction was continued for 30 minutes. The product was filtered, washed with water, and dried at 50°C to obtain silver-doped titanium dioxide.

[0056] Amino grafting: Take 0.1 kg of surface-modified silver-doped titanium dioxide and disperse it in 0.5 L of water. Heat it to 50°C, then add 0.6 kg of amino-polyethylene glycol-thiol (polyethylene glycol molecular weight is 800), stir and react for 30 minutes, filter and dry to obtain amino-grafted silver-doped titanium dioxide, which is the photocatalyst.

[0057] Preparation Example 3

[0058] A photocatalyst is prepared according to the following steps:

[0059] Raw material preparation: 2 kg of ethanol is placed in a preparation tank, and 1 kg of tetrabutyl titanate is added dropwise while stirring. After the addition is complete, 0.1 kg of 1 mol / L silver nitrate solution is added and mixed evenly to obtain a precursor solution; 0.75 kg of anhydrous acetic acid, 0.25 kg of water, and 1 kg of ethanol are mixed evenly to obtain a coagulation solution;

[0060] Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react for 30 minutes to obtain a gel.

[0061] Calcination: The gel was aged and air-dried for 4 hours, ground into powder, and the powder was calcined at 430° C. for 2 hours to obtain a crude silver-doped titanium dioxide product.

[0062] Surface modification: The crude silver-doped titanium dioxide obtained by calcination was dispersed in ethanol, 0.2 kg of KH560 was added, and after stirring for 20 minutes, 0.05 kg of sodium aminosulfonate was added and the reaction was continued for 30 minutes. The product was filtered, washed with water, and dried at 50°C to obtain silver-doped titanium dioxide.

[0063] Amino grafting: Take 0.1 kg of surface-modified silver-doped titanium dioxide and disperse it in 0.5 L of water. Heat it to 50°C, then add 0.5 kg of amino-polyethylene glycol-thiol (polyethylene glycol molecular weight is 1600), stir and react for 30 minutes, filter and dry to obtain amino-grafted silver-doped titanium dioxide, which is the photocatalyst.

[0064] Preparation Example 4

[0065] A photocatalyst, which differs from Preparation Example 1 in that sodium aminosulfate is not added in the surface modification step. The specific operation is: dispersing the crude silver-doped titanium dioxide product obtained by calcination in ethanol, adding 0.3 kg of KH-560, stirring and reacting for 30 minutes, filtering and washing with water after the reaction is completed, and drying at 50°C to obtain silver-doped titanium dioxide.

[0066] Preparation Example 5

[0067] A photocatalyst, which differs from Preparation Example 1 in that no epoxy silane coupling agent is added in the surface modification step. The specific operation is as follows: the crude silver-doped titanium dioxide product obtained by calcination is dispersed in ethanol, 0.1 kg of sodium aminosulfonate is added, and the reaction is stirred for 30 minutes. After the reaction is completed, the product is filtered, washed with water, and dried at 50°C to obtain silver-doped titanium dioxide.

[0068] Preparation Example 6

[0069] A photocatalyst differs from Preparation Example 1 in that no surface modification step is performed during the preparation process. The specific steps are as follows: raw material preparation: 2 kg of ethanol is placed in a preparation tank, 1 kg of tetrabutyl titanate is added dropwise while stirring, and after the addition is completed, 0.2 kg of 1 mol / L silver nitrate solution is added and mixed evenly to obtain a precursor solution; 0.6 kg of anhydrous acetic acid, 0.2 kg of water and 1 kg of ethanol are taken and mixed evenly to obtain a coagulation liquid.

[0070] Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react for 30 minutes to obtain a gel.

[0071] Calcination: The gel was aged and air-dried for 5 hours, ground into powder, and the powder was calcined at 450° C. for 3 hours to obtain a crude silver-doped titanium dioxide product.

[0072] Amino grafting: Take 0.1 kg of the calcined silver-doped titanium dioxide crude product and disperse it in 0.5 L of water. Heat it to 50°C, then add 0.4 kg of amino-polyethylene glycol-thiol (polyethylene glycol molecular weight is 1000), stir and react for 30 minutes, filter and dry to obtain the amino-grafted silver-doped titanium dioxide, which is the photocatalyst.

[0073] Preparation Example 7

[0074] A photocatalyst is different from Preparation Example 6 in that no amino grafting step is performed during the preparation process, and the silver-doped titanium dioxide crude product obtained by calcination is the obtained photocatalyst.

[0075] Example

[0076] The raw material specifications used in the examples of this application are:

[0077] The water-based polyurethane emulsion is a self-crosslinking polyurethane emulsion with a solid content of 35% and a viscosity of 80 cps.

[0078] The carboxyl-terminated hyperbranched polyester is HyPer H102, which has a hydroxyl value of 519 mgKOH / g and a molecular weight of 1250.

[0079] The D50 particle size of the photocatalyst is 15 to 25 nm.

[0080] The fabric is 400g / ㎡ polyester-cotton blended fabric (the ratio of polyester fiber to cotton fiber is 88:12).

[0081] Example 1

[0082] A photocatalytic formaldehyde removal fabric is prepared according to the following method:

[0083] Padding Finish: 1.2 kg of aqueous polyurethane emulsion, 0.8 kg of carboxyl-terminated hyperbranched polyester, 1.5 kg of amino-grafted silver-doped titanium dioxide obtained in Preparation Example 1, 0.6 kg of chitosan (90% deacetylation), and 0.3 kg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide were added sequentially to 12.5 kg of water and stirred evenly to prepare a finishing agent. The fabric was immersed in the finishing agent at a bath ratio of 5:1 and subjected to a double-dip and double-pad treatment. The immersion time was 1 hour, and the padding pressure was 0.2 MPa.

[0084] Drying and shaping: The rolled fabric is dried at 105°C to reduce the moisture content of the fabric to less than 0.5%, and then the fabric is placed at 130°C for wet heat shaping for 3 minutes. After shaping is completed, the fabric is cooled to obtain the photocatalytic formaldehyde removal fabric.

[0085] Example 2

[0086] A photocatalytic formaldehyde removal fabric is prepared according to the following method:

[0087] Padding Finish: 1.0 kg of aqueous polyurethane emulsion, 1.0 kg of carboxyl-terminated hyperbranched polyester, 1.0 kg of amino-grafted silver-doped titanium dioxide obtained in Preparation Example 2, 0.6 kg of chitosan (85% deacetylation), and 0.2 kg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide were added sequentially to 10.5 kg of water and stirred evenly to prepare a finishing agent. The fabric was immersed in the finishing agent at a bath ratio of 5:1 and subjected to a double-dip and double-pad treatment. The immersion time was 1 hour, and the padding pressure was 0.2 MPa.

[0088] Drying and shaping: The rolled fabric is dried at 105°C to reduce the moisture content of the fabric to less than 0.5%, and then the fabric is placed at 130°C for wet heat shaping for 3 minutes. After shaping is completed, the fabric is cooled to obtain the photocatalytic formaldehyde removal fabric.

[0089] Example 3

[0090] A photocatalytic formaldehyde removal fabric is prepared according to the following method:

[0091] Padding Finish: 1.5 kg of aqueous polyurethane emulsion, 0.6 kg of carboxyl-terminated hyperbranched polyester, 1.8 kg of amino-grafted silver-doped titanium dioxide (prepared in Preparation Example 3), 1 kg of chitosan (90% deacetylation), and 0.4 kg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide were added sequentially to 13 kg of water and stirred evenly to prepare a finishing agent. The fabric was immersed in the finishing agent at a bath ratio of 5:1 and subjected to a double-dip and double-pad treatment. The immersion time was 1 hour, and the padding pressure was 0.2 MPa.

[0092] Drying and shaping: The rolled fabric is dried at 105°C to reduce the moisture content of the fabric to less than 0.5%, and then the fabric is placed at 130°C for wet heat shaping for 3 minutes. After shaping is completed, the fabric is cooled to obtain the photocatalytic formaldehyde removal fabric.

[0093] Table 1. Raw material ratios of photocatalytic coatings in Examples 1 to 3 (kg)

[0094]

[0095] Example 4

[0096] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of the photocatalyst obtained in Preparation Example 4 is used instead of the photocatalyst obtained in Preparation Example 1.

[0097] Example 5

[0098] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of the photocatalyst obtained in Preparation Example 5 is used instead of the photocatalyst obtained in Preparation Example 1.

[0099] Example 6

[0100] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of the photocatalyst obtained in Preparation Example 6 is used instead of the photocatalyst obtained in Preparation Example 1.

[0101] Example 7

[0102] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide is not added to the raw materials of the catalyst coating.

[0103] Example 8

[0104] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of aqueous polyurethane emulsion is used to replace chitosan in the raw materials of the catalyst coating.

[0105] Comparative Example

[0106] Comparative Example 1

[0107] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of the photocatalyst obtained in Preparation Example 7 is used instead of the photocatalyst obtained in Preparation Example 1.

[0108] Comparative Example 2

[0109] A photocatalytic formaldehyde-removing fabric is different from Example 1 in that an equal amount of aqueous polyurethane emulsion is used in the raw materials of the catalyst coating to replace the adhesion promoter.

[0110] Performance testing

[0111] 1. Loading capacity test: According to the following calculation formula, the loading capacity Q of the photocatalytic coating on the fabric surface is determined by weight gain method. T .

[0112] Where: W0—weight of fabric before photocatalytic finishing, g;

[0113] W1—weight of fabric after photocatalytic finishing, g.

[0114] 2. Fabric formaldehyde removal rate test: According to the method steps described in Experiment 3 of the patent application with publication number CN112342780A, the 24-hour formaldehyde removal rate of the fabric was tested.

[0115] 3. Photocatalyst Shedding Rate Test: 0.5 kg of the above-mentioned photocatalytic formaldehyde-removing fabric was placed on a stainless steel mesh screen and vibrated at a frequency of 20 Hz, an amplitude of 20 cm, and a vibration time of 4 hours to cause the photocatalyst particles to fall from the fabric. A continuous airflow collected the fallen particles in a dust bag. The total weight of the fallen particles was measured by weighing them, and the ratio of the weight of the fallen particles to the weight of the original photocatalytic formaldehyde-removing fabric was calculated to obtain the shedding rate. A higher value indicates poorer photocatalyst adhesion.

[0116] 4. Fabric Softness Test: Test the warp and weft bending lengths of the fabric in accordance with GB / T 18318.1-2009, "Determination of the Flexural Properties of Textiles - Part 1: Inclined Plane Method." The smaller the bending length, the softer the fabric.

[0117] Table 2. Test results

[0118]

[0119]

[0120] Analysis of test results:

[0121] (1) As can be seen from Examples 1 to 8 and Comparative Examples 1 to 2 in conjunction with Table 2, the present invention, by using amino-polyethylene glycol-mercapto-grafted silver-doped titanium dioxide as a photocatalyst, in combination with an aqueous polyurethane emulsion and a carboxyl-terminated hyperbranched polyester, can effectively improve the adhesion of the photocatalyst particles to the fabric surface, reduce the probability of peeling off, and thus improve the durability of the fabric's photocatalytic effect. This may be because the carboxyl-terminated hyperbranched polyester has excellent cross-linking properties and can cross-link with the aqueous polyurethane emulsion and the aforementioned amino-polyethylene glycol-mercapto-grafted silver-doped titanium dioxide to form a strong chemical connection.

[0122] Furthermore, in combination with Example 1 and Comparative Example 2, it can be seen that the addition of end-carboxyl hyperbranched polyester can not only improve the adhesion of silver-doped titanium dioxide on the fabric, but also improve the softness of the fabric after finishing, which is beneficial to prevent cracking due to low softness of the coating and ensure the durability of the photocatalytic formaldehyde removal fabric.

[0123] (2) Combining Example 1 with Examples 4 to 6 and Table 2, it can be seen that the surface modification of silver-doped titanium dioxide using an epoxy silane coupling agent and sodium aminosulfonate can effectively improve the formaldehyde removal effect after fabric finishing. The reason may be that the epoxy silane coupling agent reacts with the silver-doped titanium dioxide, thereby introducing epoxy groups onto its surface, and then the epoxy groups react with sodium aminosulfonate to obtain negatively charged silver-doped titanium dioxide. The steric hindrance of the silane chain and the electrostatic effect of the sulfonic acid group effectively promote the dispersion of the photocatalyst particles and inhibit agglomeration. This is conducive to improving the loading rate of the photocatalyst, ensuring that the particles can be firmly attached, and reducing the shedding rate.

[0124] (3) Combining Examples 1 and 8 with Table 2, it can be seen that the use of chitosan can help reduce the shedding rate of silver-doped titanium dioxide and improve the durability of the photocatalytic formaldehyde removal fabric. This may be because chitosan can act as a film-forming agent in the finishing agent, and its positive charge in the finishing agent can effectively adsorb the negatively charged silver-doped titanium dioxide, further improving its adhesion.

[0125] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A photocatalytic formaldehyde removal fabric, characterized in that: The invention comprises a fabric and a photocatalytic coating supported on the fabric; The raw materials of the photocatalytic coating include, by parts by mass: 10-15 parts of water-based polyurethane emulsion; 5-10 parts of adhesion promoter; 10-20 parts of modified photocatalyst; The modified photocatalyst is prepared by reacting raw materials including silver-doped titanium dioxide and amino-polyethylene glycol-thiol, wherein the mass ratio of the silver-doped titanium dioxide to the amino-polyethylene glycol-thiol is 1:(3-6); The adhesion promoter is a carboxyl-terminated hyperbranched polyester.

2. The photocatalytic formaldehyde removal fabric according to claim 1, characterized in that: The raw materials of the photocatalytic coating further include 2 to 4 parts of 1-ethyl-(3-dimethylaminopropyl)carbodiimide.

3. The photocatalytic formaldehyde removal fabric according to claim 1, characterized in that: The D50 particle size of the silver-doped titanium dioxide is 1 to 100 nm.

4. The photocatalytic formaldehyde removal fabric according to claim 1, characterized in that: The molecular weight of the polyethylene glycol in the amino-polyethylene glycol-thiol group is 800-2000.

5. The photocatalytic formaldehyde removal fabric according to claim 1, characterized in that: The silver-doped titanium dioxide is prepared by a sol-gel method, and its raw materials include, by weight: 10 parts of butyl titanate 1-3 parts silver nitrate solution 30-40 parts of ethanol Water 2-4 Anhydrous acetic acid 5-10.

6. The photocatalytic formaldehyde removal fabric according to claim 5, characterized in that: The raw material of the silver-doped titanium dioxide further includes a modifier, which includes 2 to 3 parts of an epoxy silane coupling agent and 0.5 to 1 part of sodium sulfamate.

7. The photocatalytic formaldehyde removal fabric according to claim 6, characterized in that: The preparation method of silver-doped titanium dioxide comprises the following steps: Preparation of raw materials: Take an appropriate amount of ethanol in a preparation tank, add butyl titanate dropwise under stirring, add silver nitrate solution after the addition is complete, and mix well to obtain a precursor solution; mix anhydrous acetic acid, water and the remaining ethanol to obtain a coagulation solution; Hydrolysis condensation: add the coagulation liquid dropwise to the precursor solution, stir and react to obtain a gel; Calcination: Grind the gel into powder after drying, and calcine the powder at 400-500° C. for 2-4 hours to obtain a crude silver-doped titanium dioxide product; Surface modification: The crude silver-doped titanium dioxide product was dispersed in ethanol, an epoxy silane coupling agent was added, and sodium aminosulfonate was added after stirring for reaction, and the reaction was continued to obtain silver-doped titanium dioxide.

8. The photocatalytic formaldehyde removal fabric according to claim 6, characterized in that: The raw materials of the photocatalytic coating further include 5 to 10 parts of chitosan, and the deacetylation degree of the chitosan is not less than 85%.

9. The method for preparing photocatalytic formaldehyde-removing fabric according to any one of claims 1 to 8, characterized in that: The steps include: Padding finishing: Add the raw materials of the photocatalytic coating into water to prepare a finishing agent, and immerse the fabric in the finishing agent for two-dipping and two-padding treatment; Drying and shaping: the rolled fabric is dried and shaped to obtain photocatalytic formaldehyde-removing fabric.

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