Cotton fabric modified silicon dioxide super-hydrophobic finishing agent and preparation method thereof

Abstract

The invention discloses a cotton fabric modified silicon dioxide super-hydrophobic finishing agent and a preparation method thereof in the field of fabric finishing agents, and the hydrophobic finishing agent is a mixture of waterborne polyurethane, carboxymethyl chitin, modified silicon dioxide and water, the modified silicon dioxide is prepared from the following raw materials: nano silicon dioxide powder, castor oil, sunflower bud extract, a silane coupling agent and deionized water. The super-hydrophobic finishing agent is prepared from nano silicon dioxide powder modified by castor oil and sunflower bud extract, and the surface hydrophobic layer formed after the fabric is treated by the super-hydrophobic finishing agent can effectively improve the hydrophobic performance and anti-permeation performance of the fabric; and the hydrophobic layer has good water resistance and light aging resistance, and can provide long-acting and stable hydrophobic protection for the fabric.

Description

Technical Field

[0001] This invention relates to the field of fabric finishing agents, specifically to a modified silica superhydrophobic finishing agent for cotton fabrics and its preparation method. Background Technology

[0002] Cotton fabric is one of the most commonly used fabric materials in daily life. However, cotton fabric has defects such as being prone to wrinkling, mildew, flammability, poor stain resistance, and water absorption. Therefore, in the existing processing flow, cotton fabric is often subjected to corresponding functional treatments according to its intended use.

[0003] Modified silica is one of the basic materials for hydrophobic surface treatment of materials. The hydrophobicity of modified silica comes from two aspects: first, the grafting of hydrophobic groups onto the surface of modified silica; and second, the microscopic rough structure formed by modified silica on the material surface. When using modified silica to treat fabrics for hydrophobicity, it is only necessary to prepare a hydrophobic finishing agent with modified silica as its core, and then attach it to the surface of the fabric fibers through processes such as coating and padding. Based on the hydrophobic principle of modified silica, when preparing a hydrophobic finishing agent with modified silica as its core, it is necessary not only to enhance the hydrophobicity of the modified silica itself, but also to enhance the resistance of the hydrophobic layer formed by the finishing agent on the fabric surface to water washing damage and light damage. Only in this way can long-term hydrophobic protection be provided to the fabric. Therefore, this invention proposes a modified silica superhydrophobic finishing agent for cotton fabrics and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a modified silica superhydrophobic finishing agent for cotton fabrics and its preparation method in order to solve the above-mentioned problems.

[0005] The present invention achieves the above objectives through the following technical solutions: This invention provides a modified silica superhydrophobic finishing agent for cotton fabrics, wherein the hydrophobic finishing agent is a mixture of waterborne polyurethane, carboxymethyl chitosan, modified silica and water; The raw materials for preparing modified silica include nano silica powder, castor oil, sunflower bud extract, silane coupling agent, and deionized water.

[0006] As a further optimization of the present invention, the hydrophobic finishing agent comprises, by weight, 20-30 parts of waterborne polyurethane, 12-17 parts of carboxymethyl chitosan, 10-15 parts of modified silica and 20-30 parts of water.

[0007] As a further optimization of the present invention, the raw materials for preparing modified silica, by weight, include 8-15 parts of nano silica powder, 5-8 parts of castor oil, 10-15 parts of sunflower bud extract, 10-20 parts of anhydrous ethanol, and 2-5 parts of silane coupling agent.

[0008] As a further optimization of the present invention, the preparation method of sunflower bud extract is as follows: sunflower buds are ground and then soaked in rice vinegar, filtered, and the filtrate is extracted with ethyl acetate. The extracted liquid is then subjected to rotary evaporation to obtain sunflower bud extract.

[0009] This invention also provides a method for preparing a modified silica superhydrophobic finishing agent for cotton fabrics, specifically including the following steps: (1) Disperse nano-silica in anhydrous ethanol, then add silane coupling agent dropwise, and stir thoroughly to obtain a mixture. (2) Add castor oil and sunflower bud extract to the mixture, heat the mixture to react, and filter, dry and grind the reaction product to obtain modified silica. (3) Disperse the modified silica in water to obtain a dispersion, and dissolve the carboxymethyl chitin in another part of water to obtain an aqueous solution; (4) Under heating conditions, waterborne polyurethane, dispersion and aqueous solution are mixed to obtain finishing agent.

[0010] As a further optimization of the present invention, in steps (2) and (4), the heating reaction is carried out under nitrogen protection.

[0011] As a further optimization of the present invention, in step (4), the stirring speed is 200-300 r / min, the reaction temperature is 40-60℃, and the reaction time is 2-4 h.

[0012] The beneficial effects of this invention are as follows: This invention combines castor oil and sunflower bud extract to modify nano-silica powder, and uses the obtained modified silica to prepare a superhydrophobic finishing agent. After the fabric is impregnated with this superhydrophobic finishing agent and then dried and cured, the hydrophobic layer formed on its surface has excellent hydrophobic and anti-permeability properties, as well as good wash resistance and anti-photoaging properties, providing long-lasting and stable hydrophobic protection for the fabric. Detailed Implementation

[0013] The present application will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0014] I. Materials Unless otherwise specified, all methods used in this invention are conventional methods known to those skilled in the art, and all reagents and materials used are commercially available products.

[0015] method 1. Preparation of superhydrophobic finishing agents Example 1 A modified silica superhydrophobic finishing agent for cotton fabrics, the preparation method includes the following steps: (1) Preparation of sunflower bud extract: After cleaning and grinding fresh sunflower buds, soak them in rice vinegar at a mass ratio of 1:3 for 5 hours. After filtration, collect the filtrate. Mix the filtrate with ethyl acetate at a volume ratio of 1:2. Extract the filtrate. Then, rotary evaporate the obtained extract (45℃, 0.08MPa) to obtain sunflower bud extract. (2) By weight, take 25 parts of nano silica powder, 5 parts of castor oil, 10 parts of sunflower bud extract, 40 parts of anhydrous ethanol and 2 parts of silane coupling agent (KH550), disperse the nano silica in anhydrous ethanol, add the silane coupling agent dropwise, stir thoroughly to obtain a mixture; (3) Add castor oil and sunflower bud extract to the mixture and heat it under nitrogen protection at 45°C. Filter, dry and grind the reaction product to obtain modified silica. (4) By weight, take 20 parts of waterborne polyurethane, 12 parts of carboxymethyl chitosan, 15 parts of modified silica and 30 parts of water, divide the water into two equal parts, disperse the modified silica in one part of water to obtain a dispersion, and dissolve the carboxymethyl chitosan in the other part of water to obtain an aqueous solution. (5) Under nitrogen protection at 40°C, the waterborne polyurethane, dispersion and aqueous solution were stirred and mixed at 300 r / min for 2 h to obtain the superhydrophobic finishing agent.

[0016] Example 2 A modified silica superhydrophobic finishing agent for cotton fabrics, the preparation method includes the following steps: (1) Preparation of sunflower bud extract: Same as in Example 1; (2) By weight, take 22 parts of nano silica powder, 7 parts of castor oil, 13 parts of sunflower bud extract, 35 parts of anhydrous ethanol and 3 parts of silane coupling agent (KH550), disperse the nano silica in anhydrous ethanol, add the silane coupling agent dropwise, stir thoroughly to obtain a mixture; (3) Add castor oil and sunflower bud extract to the mixture and heat it under nitrogen protection at 45°C. Filter, dry and grind the reaction product to obtain modified silica. (4) By weight, take 25 parts of waterborne polyurethane, 15 parts of carboxymethyl chitosan, 13 parts of modified silica and 25 parts of water, divide the water into two equal parts, disperse the modified silica in one part of water to obtain a dispersion, and dissolve the carboxymethyl chitosan in the other part of water to obtain an aqueous solution. (5) Under nitrogen protection at 50°C, waterborne polyurethane, dispersion and aqueous solution are stirred and mixed at 250 r / min for 3 h to obtain superhydrophobic finishing agent.

[0017] Example 3 A modified silica superhydrophobic finishing agent for cotton fabrics, the preparation method includes the following steps: (1) Preparation of sunflower bud extract: Same as in Example 1; (2) By weight, take 20 parts of nano silica powder, 8 parts of castor oil, 15 parts of sunflower bud extract, 30 parts of anhydrous ethanol and 5 parts of silane coupling agent (KH550), disperse the nano silica in anhydrous ethanol, add the silane coupling agent dropwise, stir thoroughly to obtain a mixture; (3) Add castor oil and sunflower bud extract to the mixture and heat it under nitrogen protection at 45°C. Filter, dry and grind the reaction product to obtain modified silica. (4) By weight, take 30 parts of waterborne polyurethane, 17 parts of carboxymethyl chitosan, 10 parts of modified silica and 20 parts of water, divide the water into two equal parts, disperse the modified silica in one part of water to obtain a dispersion, and dissolve the carboxymethyl chitosan in the other part of water to obtain an aqueous solution. (5) Under nitrogen protection at 60°C, the waterborne polyurethane, dispersion and aqueous solution were stirred and mixed at 200 r / min for 2 h to obtain the superhydrophobic finishing agent.

[0018] 2. Efficacy testing of superhydrophobic finishing agents The hydrophobic finishing agents obtained in Examples 1-3 were used to impregnate fabric samples (of the same material and size) (40℃, 1.5h), and the impregnated samples were dried (80℃, 45h) to obtain sample fabrics. Untreated fabric samples were used as blank controls. Performance tests were conducted on each group of sample fabrics and blank control fabrics. The test items and methods are as follows: (1) Water repellency test: Fix the fabric 30cm below the spray device and spray it with 250mL of clean water for 1min under the same conditions. Observe the degree of wetting of the fabric after treatment and compare it with the standard water repellency rating card (1-5 levels) for rating: Level 5: No water on the surface, Level 4: Small amount of water on the surface (≤5%), Level 3: Local wetting on the surface (≤20%), Level 2: Significant wetting on the surface (≤50%), Level 1: Most of the surface is wet (>50%). (2) Contact angle test: The contact angle of the water droplet on the sample surface was measured using an OCA 40 contact angle meter. A second test was conducted after the fabric was washed 30 times. The test sites and test conditions were the same for both tests. The water droplet was 10 μL. The reading was taken 1 minute after the water droplet came into contact with the fabric. During the test, 10 sites were selected for each sample to measure the contact angle in sequence. The average value of the 10 contact angle data obtained was taken as the test result of the sample contact angle. (3) Washing resistance test: ① Dry the fabric to constant weight, cool it and weigh it, record it as M0. Then immerse the fabric completely in clean water (25℃), let it stand for 30 minutes and take it out. Hang it for 1 minute to drain the surface water and weigh it again, record it as M1. Water absorption rate (%) = (M1-M0) / M0×100%; ② Wash the fabric 20 times according to the standard machine washing procedure set by AATCC, and dry it after washing; ③ Repeat step ① and test the water absorption rate of the washed fabric. The test results are shown in the table below. As can be seen from the table, compared with the blank control group, the fabric samples treated with the superhydrophobic finishing agent obtained in Examples 1-3 have a higher water repellency level, a larger surface contact angle, and a lower water absorption rate. This result shows that the superhydrophobic finishing agent proposed in this invention can significantly improve the surface hydrophobic properties of the fabric after being used to impregnate the fabric, thereby reducing the probability of water seepage and absorption.

[0019] 3. Detection of factors affecting the efficacy of superhydrophobic finishing agents (1) Comparative Examples 1 and 2: Based on Example 2, only the components of nano silica powder, castor oil and sunflower bud extract in the raw materials for preparing modified silica were adjusted (as shown in the table below). (2) Comparative Example 3: Based on Example 2, only the preparation method of sunflower bud extract was adjusted. The adjusted preparation method is as follows: after cleaning and grinding fresh sunflower buds, soak them in water at a mass ratio of 1:3 for 5 hours, collect the filtrate after filtration, mix the filtrate with ethyl acetate at a volume ratio of 1:2, extract the filtrate, and then perform rotary evaporation (45°C, 0.08 MPa) to obtain sunflower bud extract; (3) Set up Comparative Example 4: Based on Example 2, only remove the nitrogen protection conditions in steps (3) and (5).

[0020] Fabric samples were treated with the finishing agents obtained in Comparative Examples 1-4 respectively to obtain sample fabrics. The treatment method was the same as in Example 2. Performance tests were conducted on each group of sample fabrics. The test items and methods were the same as in Example 2. Since photoaging is also one of the key factors affecting fabric performance in daily life, especially fabrics with protective layers, a photoaging resistance test was added to evaluate the impact of different factors on the performance of the hydrophobic layer formed on the fabric. The specific testing method for light aging resistance test is as follows: ① Dry the fabric to constant weight, cool it and weigh it, record it as M0, then immerse the fabric completely in clean water (25℃), let it stand for 30 minutes and then take it out, hang it for 1 minute to drain the surface water, weigh it again and record it as M1, water absorption rate (%) = (M1-M0) / M0×100%; ② According to the standard specified by AATCC TM16, the fabric is subjected to 240 hours of outdoor simulated light treatment; ③ Repeat step ① and test the water absorption rate of the fabric after washing.

[0021] The test results are shown in the table below. From the table, we can see that: (1) Compared with Example 2, in Comparative Examples 1 and 2, the water repellency of the fabric is lower, the surface contact angle is smaller, and the water absorption rate is higher. This result indicates that when castor oil and sunflower bud extract are used together for silica modification, the modified silica obtained can effectively enhance the effect of superhydrophobic finishing agent, that is, enhance the hydrophobic effect and anti-permeability effect of the hydrophobic layer formed on the surface of the fabric treated with superhydrophobic finishing agent. (2) Compared with Example 2, in Examples 3 and 4, the difference in water absorption rate of the fabric before and after washing and before and after light exposure is increased. Among them, the difference between Comparative Example 4 and Comparative Example 3 is particularly significant. This result indicates that compared with sunflower bud extract obtained by water extraction (Comparative Example 3), the superhydrophobic finishing agent prepared by sunflower bud extract obtained by vinegar extraction (Example 2) has better durability of the hydrophobic layer formed on the fabric surface after being applied to the fabric. In addition, providing nitrogen protection conditions in the heat treatment process during the preparation of the superhydrophobic finishing agent can also effectively improve the performance of the superhydrophobic finishing agent, thereby improving the durability of the hydrophobic layer on the fabric surface.

[0022] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A modified silica superhydrophobic finishing agent for cotton fabrics, characterized in that: The hydrophobic finishing agent is a mixture of waterborne polyurethane, carboxymethyl chitosan, modified silica, and water. The raw materials for preparing the modified silica include nano silica powder, castor oil, sunflower bud extract, silane coupling agent, and deionized water.

2. The modified silica superhydrophobic finishing agent for cotton fabrics according to claim 1, characterized in that: The hydrophobic finishing agent comprises, by weight, 20-30 parts of waterborne polyurethane, 12-17 parts of carboxymethyl chitosan, 10-15 parts of modified silica, and 20-30 parts of water.

3. The modified silica superhydrophobic finishing agent for cotton fabrics according to claim 1, characterized in that: The raw materials for preparing the modified silica, by weight, include 8-15 parts of nano silica powder, 5-8 parts of castor oil, 10-15 parts of sunflower bud extract, 10-20 parts of anhydrous ethanol, and 2-5 parts of silane coupling agent.

4. The modified silica superhydrophobic finishing agent for cotton fabrics according to claim 2, characterized in that: The method for preparing the sunflower bud extract is as follows: sunflower buds are ground and then soaked in rice vinegar. After filtration, the filtrate is extracted with ethyl acetate, and the extracted liquid is subjected to rotary evaporation to obtain the sunflower bud extract.

5. A method for preparing a cotton fabric modified silica superhydrophobic finishing agent as described in any one of claims 1-4, characterized in that: Specifically, the following steps are included: (1) Disperse nano-silica in anhydrous ethanol, then add silane coupling agent dropwise, and stir thoroughly to obtain a mixture. (2) Add castor oil and sunflower bud extract to the mixture, heat the mixture to react, and filter, dry and grind the reaction product to obtain modified silica. (3) Disperse the modified silica in water to obtain a dispersion, and dissolve the carboxymethyl chitin in another part of water to obtain an aqueous solution; (4) Under heating conditions, waterborne polyurethane, dispersion and aqueous solution are mixed to obtain finishing agent.

6. The preparation method according to claim 5, characterized in that: In steps (2) and (4), the heating reaction is carried out under nitrogen protection.

7. The preparation method according to claim 5, characterized in that: In step (4), the stirring speed is 200-300 r / min, the reaction temperature is 40-60℃, and the reaction time is 2-4 h.

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