Fluorine-free water and oil repellent, and preparation method and application thereof

Abstract

The present application relates to a kind of fluorine-free water and oil repellent and its preparation method and application, the water and oil repellent of the present application has very strong water and oil repellent effect, and can meet its water and oil repellent demand for paper pulp molded product surface coating.The raw materials required by the method are simple and easy to obtain, the preparation method is simple and easy to operate, low in cost and environmentally friendly, and non-toxic to human body, while the water and oil repellent effect is excellent, suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of functional materials, and particularly relates to a fluorine-free water and oil repellent and a preparation method and application thereof. BACKGROUND

[0002] Paper pulp molding is a three-dimensional papermaking technology. It is a certain shape of paper product molded by a special mold on a molding machine with waste paper as raw material. It has four advantages: the raw material is waste paper, including board paper, waste carton paper, waste white edge paper, etc., the source is wide; the production process is completed by pulp making, adsorption forming, drying and setting, etc., which is harmless to the environment; it can be recycled and reused; the volume is smaller than foamed plastic, which can be overlapped, and the transportation is convenient, which is a typical green and environmentally friendly packaging product. Because there are a large number of pores in the paper pulp molding, there are disadvantages such as easy water absorption, easy oil absorption, high air permeability, etc., which greatly affect the use field of paper pulp molding products. Although certain chemicals such as rosin are added during the paper pulp molding process, but the improvement of water and oil repellency and air barrier performance of paper pulp molding is still very limited. It is an effective method to make the paper pulp molding product have good water and oil repellency by coating a continuous and dense plastic film such as polyethylene, polypropylene, polyvinyl alcohol, etc. on the surface of the paper by a flow coater, but the plastic layer and the substrate layer are difficult to separate and the coated plastic film cannot be degraded in nature, so the problem of plastic pollution cannot be completely solved. At present, C8 fluorine-containing water and oil repellent is mainly used to solve the problem of paper pulp molding product not resisting water and oil. Because C8 fluorine-containing long-chain water and oil repellent can produce perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS) in the production and use process, these two substances have biological accumulation and are difficult to degrade, and only a small amount can cause various serious diseases of organisms, so the use of C8 water and oil repellent has been restricted in the European Union, the United States, Canada and other countries. In recent years, 3M, Japan Daikin, Asahi Glass and other companies have shifted from C8 water and oil repellent to C6 or even C4 water and oil repellent, but this only reduces the harm, and it is still essentially a fluorine-containing water and oil repellent. At present, there is almost no fluorine-free water and oil repellent on the market, especially fluorine-free water and oil repellent at high temperature, which is difficult to achieve, greatly limiting industrial application. A large number of leading enterprises around the world are committed to the research and development of completely fluorine-free water and oil repellent products, and the first to master the key technology of fluorine-free water and oil repellent, which is conducive to leading the global paper and plastic industry in the future. The plastic layer and the fluorine-containing water and oil repellent are difficult to degrade and have harmful effects on the environment and human body. SUMMARY

[0003] The technical problem solved by the present application is to provide a fluorine-free water and oil repellent agent, a preparation method and application thereof.

[0004] The water and oil repellent agent comprises, by mass percentage, 3-4% of chitosan, 2-3% of acetic acid and 94-95% of water.

[0005] The degree of deacetylation of the chitosan is greater than 80%.

[0006] Further preferably, the degree of deacetylation of the chitosan is greater than 95%.

[0007] The water is deionized water.

[0008] The water and oil repellent agent comprises, by mass percentage, 3-4% of chitosan, 2-3% of acetic acid and 94-95% of water.

[0009] The water and oil repellent agent comprises, by mass percentage, 3-4% of chitosan, 2-3% of acetic acid and 94-95% of water.

[0010] (1) mixing acetic acid and water to obtain an acetic acid solution, and then dissolving chitosan in the acetic acid solution to obtain a water and oil repellent agent;

[0011] (2) coating the water and oil repellent agent on a substrate and drying to obtain a water and oil repellent material.

[0012] The preferred mode of the preparation method is as follows:

[0013] In the water and oil repellent agent in step (1), by mass percentage, chitosan is 3-4%, acetic acid is 2-3%, and water is 94-95%.

[0014] The mass percentage concentration of acetic acid in step (1) is greater than or equal to 99.5%.

[0015] The substrate in step (2) is paperboard; the paperboard is paper pulp molding, such as paper pulp molding disposable food meal boxes.

[0016] The coating method in step (2) is spraying; the coating amount is 4.5-6.2 g / m 2 .

[0017] The drying in step (2) is 20-80℃ drying for 1-3h.

[0018] Further preferably, the drying is 40-80℃ drying for 1-3h.

[0019] The application of the water and oil repellent material in the disposable food packaging.

[0020] Beneficial effects

[0021] (1) The preparation method of the fluorine-free water and oil repellent provided by the application only uses one chitosan raw material to prepare the fluorine-free water and oil repellent.

[0022] (2) The existing chitosan coating preparation method can only improve the oil repellency, but has no improvement in water repellency. The chitosan prepared by the application is filled and coated in the inside and surface of the paper pulp molded product by spraying, which can better promote the combination of the water and oil repellent and the paper pulp molded product itself, so that the chitosan is not only used as a surface coating, but also fills the pores on the surface and inside of the paper pulp molded product to prevent the penetration of oil and water, thereby achieving the improvement of the water and oil repellency of the paper pulp molded product.

[0023] (3) The application can meet the water and oil repellency requirements in daily production and life of the paper pulp molded product. After the treatment of the water and oil repellent, the water repellency of the paper pulp molded product is greatly improved, and the oil repellency is also greatly improved. The untreated paper pulp molded product has an oil-proof grade less than 1, and the highest oil-proof grade after treatment can reach 12, which has a very superior oil repellency effect. The untreated paper pulp molded product has no water-proof ability, and the contact angle is 0°. The treated product can be waterproof, and the water contact angle can reach 114.9°.

[0024] (4) The fluorine-free water and oil repellent prepared by the application has simple and easily available raw materials, is green and pollution-free, and is degradable, which meets the requirements of the food industry and does not harm the human body and the environment, thereby ensuring the health of consumers and the sustainable development of the environment. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 SEM surface of the original paper pulp molded food box and the fluorine-free water and oil repellent food box prepared in Example 1; wherein (a) surface of the original food box (b) surface of Example 1 (c) cross section of the original food box (d) cross section of Example 1;

[0026] Figure 2 SEM surface of the fluorine-free water and oil repellent food boxes prepared in Example 1 and Example 2; wherein (a) surface of Example 1 (b) surface of Example 2 (c) cross section of Example 1 (d) cross section of Example 2;

[0027] Figure 3 SEM surface of fluorine-free water / oil repellent meal box prepared for Example 1, Example 4 and Example 6; wherein (a) Example 1 surface; (b) Example 4 surface; (c) Example 6 surface; (d) Example 1 cross-section; (e) Example 4 cross-section; (f) Example 6 cross-section;

[0028] Figure 4 Comparison chart of infrared spectra of original meal box and fluorine-free water / oil repellent meal box prepared for Example 1;

[0029] Figure 5 30s water contact angle (a) and 300s water contact angle (b) of fluorine-free water / oil repellent meal box prepared for Example 1. DETAILED DESCRIPTION

[0030] The application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that after reading the content taught by the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope of the appended claims of the application.

[0031] Acetic acid: mass percentage concentration ≥ 99.5%, purchased from China Pharmaceutical Group, batch number: 20200724;

[0032] Pulp molded product: pulp molded disposable food meal box, from Lusenxin Material (Yunnan) Co., Ltd.;

[0033] Chitosan-1: viscosity of chitosan is 100-200 mPa . s, degree of deacetylation is > 95%, purchased from Aladdin, cas: 9012-76-4;

[0034] Chitosan-2: viscosity of chitosan is 50-800 mPa . s, degree of deacetylation is 80-95%, purchased from China Pharmaceutical Group, cas: 9012-76-4.

[0035] Example 1

[0036] Weigh 2g of acetic acid into 94ml of deionized water, stir to dissolve completely to prepare an acetic acid solution, weigh 4g of chitosan-1 into the acetic acid solution, stir for 5h to obtain a water / oil repellent agent, spray the water / oil repellent agent onto the pulp molded product, the coating amount is 5g / m 2 , put into an 80℃ oven and dry for 3h.

[0037] Example 2

[0038] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2 Put into 80℃ oven and dry for 3h.

[0039] Example 3

[0040] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2 Put into 60℃ oven and dry for 3h.

[0041] Example 4

[0042] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2， Put into 40℃ oven and dry for 3h.

[0043] Example 5

[0044] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2 Put into 20℃ oven and dry for 3h.

[0045] Example 6

[0046] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2 Put into 80℃ oven and dry for 3h.

[0047] Example 7

[0048] Take 2g acetic acid into 94ml deionized water, stir to make it fully dissolved to prepare acetic acid solution, take 4g chitosan-2 into the acetic acid solution, stir for 5h to obtain water and oil repellent agent, spray the water and oil repellent agent on the paper pulp molded product, the coating amount is 5g / m 2 Put into 80℃ oven and dry for 3h.

[0049] Performance test:

[0050] 1. Oil repellency test: The oil repellency grade determination method adopts the TAPPI T559 pm-96 standard, specifically: 12 solutions of different grades (Table 1) are prepared by mixing castor oil, toluene, and n-heptane in different proportions (1-12), representing the oil repellency grade from poor to excellent. In each test, a solution of a certain grade is added to the sample for 15 seconds, and then wiped off. If there is no oil stain left on the surface of the paper after 15 seconds, it is considered that the oil repellency test of the solution of this grade is passed, and then a solution of a higher oil repellency grade is tested until the surface test fails. The average value of three experimental data is taken for each sample. If the 1st grade test fails, the oil repellency grade is 0. The higher the oil repellency grade, the stronger the oil repellency of the sample, and the better the practicality.

[0051] Table 1 Determination of grease resistance of coated paper samples according to TAPPI T559 pm-96 standard

[0052]

[0053]

[0054] 2. Hot oil resistance test: The hot oil resistance test mainly adopts the GB / T 36787-2018 test standard, specifically: Place the paper lunch box on a dry glass plate, and inject edible oil and water at 95℃±5℃ to a distance of 6mm from the mouth of the paper lunch box. Cover and observe the sample for deformation, cracking, surface peeling, and wrinkling after 30 minutes of standing. Observe whether there is oil or water seepage or leakage at the bottom and side of the sample.

[0055] 3. Hot water resistance test: The hot water resistance test mainly adopts the GB / T 36787-2018 test standard, specifically: Place the sample on a dry glass plate or flat plate lined with filter paper, and fill it with water at 95℃±5℃. After 30 minutes of standing, observe the sample for deformation, bottom seepage, and leakage. Three samples are tested for each sample, and if none of the three samples shows seepage, leakage, or deformation, the sample is determined to have no seepage, no leakage, and no deformation. (Note: During the test, water vapor condensation occurs at the bottom due to the temperature difference between the inside and outside of the sample. This phenomenon is not considered as seepage or leakage.)

[0056] Wherein: √: no leakage; ○: only a little leakage; △: some leakage, but no seepage; X: most of the leakage; The performance of the prepared fluorine-free water and oil repellent agent was tested, and the test results are shown in Table 2.

[0057] Table 2 Performance test table of fluorine-free water and oil repellent agent

[0058] Examples Oil repellency rating Hot oil resistance performance 30 s water contact angle Hot water resistance performance Original meal box 0 X 0 X Example 1 12 √ 114.9° √ Example 2 8 ○ 103.7° ○ Example 3 11 √ 106.5° ○ Example 4 7 ○ 101.1° △ Example 5 4 △ 97.7° X Example 6 3 △ 92.5° X Example 7 0 X 82.6° X

[0059] Product characterization:

[0060] Specifically as Figure 1 , 2 , 3, 4.

[0061] The surface and cross-section of the original meal box and the fluorine-free water and oil repellent sample prepared in Example 1 above were scanned by scanning electron microscope (SEM), and the comparison results are shown in Figure 1 It can be seen that the fiber voids of the original meal box are relatively large, and the cross-section is relatively loose. After spraying the fluorine-free water and oil repellent agent, the fiber voids of the meal box are filled, the surface becomes smooth and flat, and the cross-section becomes more compact, indicating that the chitosan is successfully filled in the fiber inside and surface. The cross-section of the coated meal box becomes very compact from the original loose and dispersed, indicating that the chitosan filling of the meal box pores is not limited to the surface layer, but acts on the entire meal box.

[0062] The surface and cross-section of the fluorine-free water and oil repellent samples prepared in Example 1 and Example 2 above were scanned by scanning electron microscope (SEM), and the comparison results are shown in Figure 2 . Figure 2 It can be seen from (b) and (d) that after the meal box is coated with 80-95% deacetylation degree chitosan, the pores on the surface of the fiber are filled to a certain extent, and the surface is covered with a chitosan film. Therefore, compared with the original meal box, the water and oil repellency of the chitosan-coated meal box has been improved to a certain extent. Figure 2 It can be seen from (a) and (c) that compared with the coating of low deacetylation degree chitosan solution, the higher deacetylation degree chitosan solution fills the pores of the meal box better, and the entire surface is basically completely filled. Therefore, the chitosan-coated meal box with higher deacetylation degree has better water and oil repellency.

[0063] The surface (a) (b) (c) and cross-section (d) (e) (f) of the fluorine-free water and oil repellent samples prepared in Example 1, Example 4, and Example 6 above were scanned by scanning electron microscope (SEM), and the comparison results are shown in Figure 3 It can be seen from the figure that when the chitosan concentration is 4% and the temperature is 80°C, the surface and cross-section are more compact, and the water repellency is better. When the chitosan concentration is reduced to 3% at the same temperature, the fiber voids cannot be filled, and the water repellency will be reduced.

[0064] The original meal box and the fluorine-free water and oil repellent sample prepared in Example 1 above were tested by Fourier infrared spectrometer equipped with attenuated total reflection accessory (ATR), and the comparison results are shown in Figure 4 The -NH characteristic peak at 1540 cm -1 proves the successful introduction of chitosan. In addition, the characteristic peak of -OH at 3500 cm -1The -OH peak of the treated sample became weak, because the hydrogen bond was formed between the chitosan and the cellulose fiber in the lunch box, and the hydroxyl group was consumed, so the water repellency was greatly improved.

[0065] The water contact angle (a) for 30s and water contact angle (b) for 300s of the original lunch box and the fluorine-free water and oil repellent sample prepared in Example 1 above were measured by a contact angle measuring instrument, and the comparison results are shown in Table 1. Figure 5 Since the original lunch box was immediately penetrated by water and oil in 30s, the contact angle was 0°, so no figure was attached, and the water repellency of the lunch box coated with chitosan was greatly improved, and the contact angle for 30s was increased to 114.9°, and the water contact angle after 300s was still maintained at 111.9°.

Claims

1. A water- and oil-repellent material, characterized in that, The water- and oil-repellent material is a material coated with a water- and oil-repellent agent; The water- and oil-repellent agent comprises, by mass percentage: 4% chitosan, 2%-3% acetic acid, and 94%-95% water, with the sum of the mass percentages of all components being 100%; wherein the degree of deacetylation of chitosan is greater than 95%. The method for preparing the water- and oil-repellent material includes: (1) Mix acetic acid and water to obtain an acetic acid solution, and then dissolve chitosan in the acetic acid solution to obtain a water-repellent and oil-repellent agent; (2) Apply the water-repellent and oil-repellent agent to the substrate and dry it to obtain the water-repellent and oil-repellent material; wherein the substrate is paperboard; the drying is carried out at 60-80℃ for 1-3 hours.

2. A method for preparing the water- and oil-repellent material according to claim 1, comprising: (1) Mix acetic acid and water to obtain an acetic acid solution, and then dissolve chitosan in the acetic acid solution to obtain a water-repellent and oil-repellent agent; (2) Apply the water- and oil-repellent agent to the substrate and dry it to obtain the water- and oil-repellent material; The substrate is cardboard; the drying process involves drying at 60-80℃ for 1-3 hours.

3. The preparation method according to claim 2, characterized in that, In step (1), the mass percentage concentration of acetic acid is ≥99.5%.

4. The preparation method according to claim 2, characterized in that, The paperboard mentioned in step (2) is molded pulp.

5. The preparation method according to claim 2, characterized in that, In step (2), the coating is applied by spraying; the coating amount is 4.5-6.2 g / m³. 2 .

6. The application of the water- and oil-repellent material of claim 1 in disposable food packaging.

Images