Method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles

Abstract

The present invention belongs to the technical field of pulping and papermaking, and in particular relates to a method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, specifically comprising: soaking the waste cotton textiles in an alkaline solution, filtering them to dry, boiling them in the alkaline solution, squeezing, crushing them, and sieving them; performing a bleaching treatment; oxidizing the bleached product fibers, separating the fibers, and further mechanically treating them until the fibers are completely dispersed to a nanometer size; adding a calcium ion solution under mechanical stirring conditions; adding polyethyleneimine to make the fiber mixture positively charged; dripping the resulting mixture onto the surface of paper, applying it evenly with an applicator, and drying it to obtain paper. The present invention shortens the process flow for preparing waste cotton textiles, saves the cost of processing waste cotton textiles, fully utilizes the heavy metal ions that may be present in the waste cotton textiles, and converts them into new materials that can be used for antibacterial purposes; solves the problem of metal ion processing and improves the utilization of metal ions.

Description

Technical Field

[0001] The invention belongs to the technical field of pulping and papermaking, and in particular relates to a method for preparing packaging paper with antibacterial and oil-resistant properties by utilizing waste cotton textiles. Background Art

[0002] With the improvement of living standards, the development of the textile industry, and the increasing material abundance, clothing consumption has increased rapidly, shortening the lifecycle of textiles and causing a continuous increase in the amount of textile waste. According to statistics, the annual global production of textile waste is approaching 100 million tons. Currently, the majority of textile waste is still incinerated or landfilled, resulting in not only a waste of resources but also significant environmental pollution. Therefore, the recycling and reuse of textile waste has become a major concern.

[0003] my country is a major cotton producer in the world. Cotton fiber is one of the most important textile raw materials and the most produced natural fiber. Cotton textiles are popular due to their excellent moisture absorption and breathability, superior feel, and strength. Consequently, pure cotton and cotton-containing textiles account for a significant proportion of textile waste. In recent years, with growing environmental awareness, the recycling of cotton fabrics and yarns has garnered significant attention both domestically and internationally.

[0004] Waste cotton textiles contain a large number of dyes, primarily acid dyes, basic dyes, and direct dyes. Acid and basic dyes are bound to textiles through non-covalent bonds, while direct dyes are covalently linked to reactive groups on textiles. This makes the decolorization and reuse of waste cotton textiles very difficult. Furthermore, textiles also contain various dyeing auxiliaries and metal ions. These issues pose certain challenges to the recycling and reuse of waste cotton textiles.

[0005] Therefore, it is necessary to design a recycling process based on the characteristics of waste cotton textile raw materials; it is urgent to develop a recycling method tailored to the characteristics of waste cotton textile raw materials. Summary of the Invention

[0006] The present invention addresses the problem of high residual dyes and metal ions in the raw materials during the recycling of waste cotton textiles. It proposes a solution that can achieve rapid bleaching of fibers in waste cotton textiles and utilize the residual metal ions therein to prepare high-performance antibacterial materials, thereby shortening the treatment process of waste cotton textiles, improving the regeneration efficiency of waste cotton textiles, and enhancing the economic benefits of the comprehensive utilization of waste cotton textiles.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, comprising the following process steps:

[0009] (1) Dismantle the waste cotton textiles and add them into 0.04%-1% alkali solution (preferably sodium hydroxide or potassium hydroxide) at room temperature for one night, filter and set aside, then cook the treated waste cotton fibers in 0.04%-1% alkali solution at 40-120°C for 1 hour, and finally press, crush and sieve the pulp obtained from the waste cotton textile treatment to obtain the required preliminary raw materials;

[0010] (2) adding copper ions as a catalyst and bleaching the pulp obtained in (1) with hydrogen peroxide at pH 3-6 to obtain a primary bleached product, adjusting the solution to alkaline and pressing for later use;

[0011] (3) Oxidation of the fibers by TEMPO oxidation: Mix the pressed pulp with TEMPO reagent and sodium bromide (fiber solid content not higher than 1%), stir thoroughly and mix well, then add sodium hypochlorite. During the process, keep the pH of the solution in the range of 10-11. React under mechanical stirring for at least 3 hours. Add ethanol to terminate the reaction and adjust the pH to 7-8. After separating the fibers, further mechanical treatment is performed until the fibers are completely dispersed and the transparency no longer increases.

[0012] (4) After the fibers are dispersed, calcium ion solution is added under mechanical stirring. Since the strength of the chelation between calcium ions and carboxyl groups is greater than the hydrogen bond between fibers, the strength of the network structure between fiber molecules is enhanced by the chelation between carboxyl groups and calcium ions. The amount of calcium ions added is related to the fiber raw material and needs to be controlled before the fiber viscosity begins to increase. If the calcium ion concentration is too low, the enhancement effect on the network structure strength is not obvious. If the calcium ion concentration is too high, the network structure will be loose, which is not conducive to the control of oleophobicity.

[0013] (5) Continuously mechanically stirring and adding polyethyleneimine. On the one hand, polyethyleneimine is a positively charged polymer that can enhance the antibacterial properties of paper; on the other hand, the addition of polyethyleneimine can neutralize the positive charge carried by the fiber, which is conducive to the uniform coating of the prepared fiber dispersion on the paper surface;

[0014] (6) Add the above mixed liquid dropwise to the surface of the paper, apply it evenly with a coater, and dry it at room temperature and pressure;

[0015] (7) Wet the paper with water and then dry it to prevent the surface from becoming uneven.

[0016] In this invention, heavy metal ions are fixed in the paper coating raw material by complexing with carboxyl groups in cellulose and -N-, -NH-, and -NH2 in polyethyleneimine, ultimately coating the paper surface. When bacteria come into contact with the paper surface, the heavy metal ions can produce an antibacterial effect by disrupting the integrity of the bacterial cell membrane.

[0017] Calcium compounds that can provide the calcium ion solution include calcium chloride, calcium nitrate, and other compounds. Their aqueous solutions contain free calcium ions that can complex with the carboxyl groups in TEMPO-oxidized cellulose. The calcium ion concentration is 0.05-0.2M.

[0018] The amount of polyethyleneimine used is based on "making the fiber mixture positively charged", and the specific amount is approximately: 0.5-1g / mL.

[0019] During the bleaching process, copper ions are added as a catalyst, using Fenton reaction to catalyze hydrogen peroxide to produce hydroxyl radicals. Hydroxyl radicals have a much greater oxidative activity than hydrogen peroxide, resulting in a more effective bleaching effect. The specific copper ion dosage is 0.5–2 mg / L in the final reaction solution.

[0020] Beneficial effects

[0021] The present invention discloses a method for preparing packaging paper with antibacterial and oil-resistant properties by utilizing waste cotton textiles. The present invention shortens the process flow of preparing waste cotton textiles and saves the cost of treating waste cotton textiles. By using waste cotton textiles to prepare packaging paper with antibacterial and oil-resistant properties, the present invention fully utilizes heavy metal ions (such as iron ions, calcium ions, etc.) that may exist in waste cotton textiles and converts them into new materials that can be used for antibacterial purposes. The present invention solves the problem of metal ion treatment and improves the utilization of metal ions.

[0022] By converting the hydroxyl groups on the fiber surface into carboxyl groups, the hydrophilic and oleophobic properties of cellulose are increased. The oxidation and mechanical dispersion process of the fibers can enable the fibers to form a smaller nanocellulose structure. This structure can fill the pores on the surface of the paper, reduce the surface roughness of the paper, and improve the barrier properties of the paper. The addition of calcium ions further increases the density of the network structure between fiber molecules, thereby further improving the oleophobic properties of the paper surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Surface macroscopic morphology of the antibacterial and oil-resistant packaging paper of the present invention;

[0024] Figure 2 : SEM image of base paper;

[0025] Figure 3 : SEM image of the antibacterial and oil-resistant packaging paper of the present invention;

[0026] Figure 4 : Inhibition zone diagram of paper inhibiting the growth of Staphylococcus aureus. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below. Before describing, it should be understood that the terms used in this specification and the appended claims should not be interpreted as limited to the general meaning and dictionary meaning, but should be interpreted according to the meaning and concept corresponding to the technical aspects of the present invention on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the descriptions presented here are merely preferred examples for illustrative purposes and are not intended to limit the scope of the present invention. It should be understood that other equivalents or improvements can be obtained therefrom without departing from the spirit and scope of the present invention.

[0028] The following examples are merely examples of embodiments of the present invention and do not constitute any limitation thereto. Those skilled in the art will appreciate that modifications without departing from the spirit and scope of the present invention fall within the scope of protection of the present invention. Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products.

[0029] Example 1

[0030] A method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, comprising the following process steps:

[0031] (1) Dismantle the waste cotton textiles and add them to a 0.04% sodium hydroxide solution and soak them at room temperature overnight. Drain and set aside. Then, cook the treated waste cotton fibers in a 0.04% sodium hydroxide solution at 40°C for 1 hour. Finally, press, crush, and sieve the pulp obtained from the waste cotton textile treatment to obtain the required preliminary raw materials.

[0032] (2) adding copper ions and bleaching the pulp obtained in (1) with hydrogen peroxide at pH 3 to obtain a primary bleached product, adjusting the solution to alkaline and pressing for later use;

[0033] (3) Oxidation of the fibers by TEMPO oxidation, separation of the fibers, and further mechanical treatment until the fibers are completely dispersed and the transparency no longer increases;

[0034] (4) After the fibers are dispersed, calcium ion solution is added under mechanical stirring to enhance the strength of the fiber molecular network structure through the chelation of carboxyl groups and calcium ions. The amount of calcium ions added is related to the fiber raw material and needs to be controlled before the fiber viscosity begins to increase. The high or low calcium ion concentration will reduce the subsequent experimental results.

[0035] (5) Continuous mechanical stirring and adding polyethyleneimine to make the fiber mixture positively charged;

[0036] (6) Add the above mixed liquid dropwise to the surface of the paper, apply it evenly with a coater, and dry it at room temperature and pressure;

[0037] (7) Wetting the paper with water and then drying it to prevent the surface from becoming uneven, thereby obtaining the antibacterial and oil-resistant packaging paper.

[0038] The calcium ion solution is an aqueous solution of calcium chloride, containing free calcium ions, which can complex with the carboxyl groups in the TEMPO-oxidized cellulose. The concentration of the calcium ions is 0.05M.

[0039] The amount of polyethyleneimine used is based on "making the fiber mixture liquid positively charged", and the specific amount is approximately: 0.5g / mL.

[0040] During the bleaching process, copper ions are added as a catalyst, using Fenton catalysis to generate hydroxyl radicals from hydrogen peroxide. Hydroxyl radicals have a much greater oxidative activity than hydrogen peroxide, resulting in a better bleaching effect. The specific amount of copper ions used is 0.5 mg / L in the final reaction solution.

[0041] The prepared wrapping paper was subjected to performance tests. The specific test methods and test data are as follows:

[0042] (1) The KIT value method was used to test the oleophobic properties of paper. Non-polar solutions No. 1 to No. 12 were prepared in descending order. After the solution was added to the paper surface for 20 seconds, the droplet was wiped off and the reagent was observed to see whether it entered the paper. The KIT value increased from 1 for the original paper to 9−10.

[0043] (2) Using a scanning electron microscope to observe the morphological changes of the paper surface, determine the reasons for the changes in the barrier properties of the paper; the SEM images of the base paper and the antibacterial and oil-resistant packaging paper of the present invention are shown in Figure 2. Figure 2 、 Figure 3 shown.

[0044] (3) The antibacterial properties of paper can be determined by detecting the inhibition zone. The inhibition zone of paper that inhibits the growth of Staphylococcus aureus is as follows: Figure 4 As shown in the figure, A is the base paper, and B is the antibacterial and oil-resistant packaging paper of the present invention.

[0045] Example 2

[0046] A method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, comprising the following process steps:

[0047] (1) Dismantle the waste cotton textiles and add them to a 1% potassium hydroxide solution and soak them at room temperature overnight. Drain and set aside. Then, cook the treated waste cotton fibers in a 1% potassium hydroxide solution at 120°C for 1 hour. Finally, press, crush, and sieve the pulp obtained from the waste cotton textile treatment to obtain the required preliminary raw materials.

[0048] (2) adding copper ions and bleaching the pulp obtained in (1) with hydrogen peroxide at pH 6 to obtain a primary bleached product, adjusting the solution to alkaline and pressing for later use;

[0049] (3) Oxidation of the fibers by TEMPO oxidation, separation of the fibers, and further mechanical treatment until the fibers are completely dispersed and the transparency no longer increases;

[0050] (4) After the fibers are dispersed, calcium ion solution is added under mechanical stirring to enhance the strength of the fiber molecular network structure through the chelation of carboxyl groups and calcium ions. The amount of calcium ions added is related to the fiber raw material and needs to be controlled before the fiber viscosity begins to increase. The high or low calcium ion concentration will reduce the subsequent experimental results.

[0051] (5) Continuously mechanically stir and add polyethyleneimine to make the fiber mixture positively charged;

[0052] (6) Add the above mixed liquid dropwise to the surface of the paper, apply it evenly with a coater, and dry it at room temperature and pressure;

[0053] (7) Wet the paper with water and then dry it to prevent the surface from becoming uneven.

[0054] The calcium ion solution is an aqueous solution of calcium nitrate, containing free calcium ions, which can complex with the carboxyl groups in the cellulose after TEMPO oxidation. The concentration of the calcium ions is 0.2M.

[0055] The dosage of the polyethyleneimine is 1 g / mL.

[0056] During the bleaching process, copper ions are added as a catalyst. Using Fenton reaction, hydrogen peroxide generates hydroxyl radicals. The oxidative activity of hydroxyl radicals is much greater than that of hydrogen peroxide, resulting in a better bleaching effect. The specific copper ion dosage is 2 mg / L.

[0057] Example 3

[0058] A method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, comprising the following process steps:

[0059] (1) Dismantle the waste cotton textiles and add them to a 0.5% potassium hydroxide solution and soak them at room temperature overnight. Drain and set aside. Then, cook the treated waste cotton fibers in a 0.5% potassium hydroxide solution at 90°C for 1 hour. Finally, press, crush, and sieve the pulp obtained from the treatment of the waste cotton textiles to obtain the required preliminary raw materials.

[0060] (2) adding copper ions and bleaching the pulp obtained in (1) with hydrogen peroxide at pH 5 to obtain a primary bleached product, adjusting the solution to alkaline and pressing for later use;

[0061] (3) Oxidation of the fibers by TEMPO oxidation, separation of the fibers, and further mechanical treatment until the fibers are completely dispersed and the transparency no longer increases;

[0062] (4) After the fibers are dispersed, calcium ion solution is added under mechanical stirring to enhance the strength of the fiber molecular network structure through the chelation of carboxyl groups and calcium ions. The amount of calcium ions added is related to the fiber raw material and needs to be controlled before the fiber viscosity begins to increase. The high or low calcium ion concentration will reduce the subsequent experimental results.

[0063] (5) Continuously mechanically stir and add polyethyleneimine to make the fiber mixture positively charged;

[0064] (6) Add the above mixed liquid dropwise to the surface of the paper, apply it evenly with a coater, and dry it at room temperature and pressure;

[0065] (7) Wet the paper with water and then dry it to prevent the surface from becoming uneven.

[0066] The calcium ion solution is an aqueous solution of calcium chloride, containing free calcium ions, which can complex with the carboxyl groups in the TEMPO-oxidized cellulose. The concentration of the calcium ions is 0.1M.

[0067] The dosage of the polyethyleneimine is: 0.8 g / mL.

[0068] During the bleaching process, copper ions are added as a catalyst. Fenton catalyst reacts with hydrogen peroxide to produce hydroxyl radicals. The oxidative activity of hydroxyl radicals is much greater than that of hydrogen peroxide, resulting in a better bleaching effect. The specific dosage of copper ions is 1mg / L.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles, characterized in that: The process steps include: (1) Dismantling waste cotton textiles and soaking them in alkali solution for a certain period of time, filtering and drying, then steaming the treated waste cotton fibers in alkali solution to obtain pulp, and then squeezing, crushing, and sieving the obtained pulp to obtain preliminary raw materials; (2) adding copper ions and bleaching the preliminary raw material obtained in step (1) with hydrogen peroxide to obtain a primary bleached product, adjusting the solution to alkaline, and squeezing the primary bleached product to obtain a bleached product; (3) oxidizing the bleached product fibers obtained in step (2), separating the fibers, and further mechanically treating the fibers until the fibers are completely dispersed to nanometer size; (4) adding a calcium ion solution to the product obtained in step (3) under mechanical stirring; The fiber mixture was continuously stirred mechanically and polyethyleneimine was added to make it positively charged; (6) adding the mixed solution obtained in step (5) dropwise onto the surface of the paper, applying it evenly with a coater, and drying it to obtain paper; (7) Wetting the paper obtained in step (6) with water and then drying it to obtain the packaging paper with antibacterial and oil-resistant properties.

2. The method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles according to claim 1, characterized in that: In step (1), the alkali solution is a 0.04%-1% sodium hydroxide or potassium hydroxide solution.

3. The method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles according to claim 2, characterized in that: In step (1), the waste cotton textiles are soaked in an alkaline solution at room temperature overnight.

4. The method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles according to claim 3, characterized in that: In step (1), the treated waste cotton fibers are steamed in an alkaline solution at 40-120° C. for 1 hour.

5. The method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles according to claim 1, characterized in that: In step (2), the pulp is bleached using hydrogen peroxide at a pH of 3-6.

6. The method for preparing packaging paper with antibacterial and oil-resistant properties by using waste cotton textiles according to claim 1, characterized in that: In step (3), the fibers are oxidized using TEMPO oxidation.

7. The method for preparing packaging paper with antibacterial and oil-resistant properties using waste cotton textiles according to claim 1, characterized in that: In step (4), the concentration of calcium ions is 0.05-0.2M.

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