Preparation method of all-bamboo-fiber basic color paper cup body paper and product of all-bamboo-fiber basic color paper cup body paper

Abstract

The invention discloses a preparation method of all-bamboo fiber basic color paper cup body paper and a product thereof, and the preparation method comprises the following steps: mechanically grinding bamboo chemical pulp fibers and bamboo chemical thermo-mechanical pulp fibers as raw materials, carrying out biological treatment on the bamboo chemical thermo-mechanical pulp fibers by using laccase / mediator, and preparing the paper cup body paper by adopting a three-layer composite papermaking process. The paper cup body paper is composed of a surface layer (bamboo chemical pulp), a core layer (bamboo chemical thermo-mechanical pulp treated by laccase / ABTS) and a bottom layer (bamboo chemical pulp), and aluminum sulfate, rosin size and CPAM are added in the papermaking process. The technical problems that the production cost is high due to the fact that traditional unbleached paper cup body paper depends on wood pulp, and bamboo pulp fibers are difficult to give consideration to high bulkness and high strength are solved, the raw material cost is low, the production process is environmentally friendly, the product has excellent physical strength, bulkness and water resistance, wood resource consumption can be reduced, and sustainable development of the papermaking industry is promoted.

Description

Technical Field

[0001] This invention relates to the field of papermaking technology, specifically to a method for preparing a base paper for all-bamboo fiber colored paper cups and its product. Background Technology

[0002] With the rapid development of my country's economy and society, the domestic paper industry has grown rapidly, and the demand for disposable paper cups has increased year by year. Paper cup base paper typically consists of three layers, with the core layer having a significant impact on the stiffness and bulk of the base paper. Currently, the core layer of the base paper is usually made from wood chemimechanical pulp. However, my country's wood resources are limited, and wood pulp mainly relies on imports, which are expensive. In contrast, my country has abundant bamboo resources, and with the introduction of the "bamboo-for-plastic" policy, the application of bamboo in the papermaking field is receiving increasing attention.

[0003] Chemimechanical pulp fibers, due to their high lignin content, exhibit good stiffness and high paper bulk. However, their poor inter-fiber bonding and insufficient flexibility result in lower folding strength in the finished paper. Therefore, it is necessary to rationally modify chemimechanical pulp while preserving its advantages to improve the quality of the pulp fibers and the overall performance of the finished paper.

[0004] Currently, pulp fiber modification methods typically include physical modification, chemical modification, and biological modification. With increasingly stringent environmental protection requirements, the traditional pulp and paper industry faces severe pollution pressure, and the promotion and application of bio-enzyme technology is gradually becoming a new focus of attention. Among the many new technologies in the paper industry, enzyme-modified pulp treatment demonstrates significant potential and advantages due to its environmental friendliness, low energy consumption, and minimal fiber damage.

[0005] Laccase, a copper-containing polyphenol oxidase, catalyzes the degradation of various aromatic compounds, especially phenols (such as aminophenol, polyphenols, and polyamines). In the presence of oxygen, laccase promotes the oxidation of phenolic structural units in lignin, generating phenolic oxygen radicals, while molecular oxygen is reduced to water. Notably, laccase has a relatively low redox potential, meaning that when used alone, it can only oxidize phenolic lignin structures. However, when oxygen and specific electron transport mediators are present in the system, the oxidative capacity of laccase is extended, allowing it to act on non-phenolic lignin structures.

[0006] Based on the above situation, there is an urgent need to develop a technology for preparing unbleached paper cup base paper that uses bamboo pulp fiber as raw material and combines low cost with high comprehensive performance, so as to reduce dependence on wood resources and promote the sustainable development of the paper industry. Summary of the Invention

[0007] The technical problem to be solved by this invention is to provide a method for preparing all-bamboo fiber basic colored paper cup base paper and its product. The method uses bamboo chemithermomechanical pulp to partially or completely replace traditional wood chemithermomechanical pulp as the core layer, and combines optimized retention aids and sizing agents to obtain all-bamboo fiber basic colored paper cup base paper with high bulk and high strength. This solves the technical problems of high cost due to reliance on wood pulp in traditional uncolored paper cup base paper and the difficulty in achieving high bulk and high strength simultaneously with bamboo pulp fiber, while reducing environmental pollution in the production process.

[0008] This invention is implemented as follows: A method for preparing a base paper for all-bamboo fiber colored paper cups, the method comprising the following steps: (1) Pulping treatment: The bamboo chemical pulp fiber and bamboo chemical mechanical pulp fiber are mechanically pulped to achieve a freeness of 30-60°SR. (2) Biomodification treatment: The pH of the bamboo chemimechanical pulp fiber obtained in step (1) was adjusted to 4.5-5.5, and laccase and mediator ABTS were added successively. The mixture was treated at 60±5℃ for 30-180 minutes. After treatment, the mixture was washed until neutral. The amount of laccase used was 0.05-0.35 U / g and the amount of mediator ABTS used was 0.2-1.0% based on the weight of oven-dry pulp fiber. (3) Papermaking and lamination: A three-layer paper structure is adopted, wherein the top and bottom layers are composed of bamboo chemical pulp fibers obtained in step (1), and the core layer is composed of bamboo chemical mechanical pulp fibers processed in step (2); the core layer accounts for 30-60% of the total mass of the three-layer paper, and the top and bottom layers are equal in mass; the three layers are made separately. During papermaking, aluminum sulfate is first added to the pulp and stirred to adjust the pH to 5.5-6.5, then anionic rosin gum is added to react, and finally cationic polyacrylamide is added and stirred before papermaking; the three wet paper webs are wet-laminated, pressed, and finally dried to obtain the all-bamboo fiber basic colored paper cup base paper.

[0009] Furthermore, in step 1, the bamboo chemical pulp and bamboo chemimechanical pulp are ground to a beating degree of 30-60ºSR using a pulping machine at a pulp concentration of 5-15%.

[0010] Furthermore, the bamboo chemimechanical pulp in step 1 is a bamboo chemithermomechanical pulp.

[0011] Furthermore, step 2 is detailed as follows: Biological modification treatment: Take refined bamboo chemimechanical pulp and adjust the pH to 4.5-5.55 with sodium acetate-glacial acetic acid buffer solution; then add laccase to treat the pulp, knead it evenly, and then add mediator solution to adjust the pulp fiber concentration to 5-15%; after mixing evenly, treat it in a constant temperature water bath at 60±5℃ for 30-180 minutes, kneading it once every 15 minutes during the process; after the treatment, wash it with a filter until neutral and refrigerate it for later use; Among them, based on the weight of oven-dry pulp fiber, the amount of laccase is 0.05-0.35 U / g pulp fiber, and the amount of mediator ABTS is 0.2-1.0%.

[0012] Furthermore, in step 3, based on the weight of oven-dry pulp fibers, the dosage of retention aid and filter aid cationic polyacrylamide is 0.02-0.1%, the dosage of aluminum sulfate is 0.5-2.5%, and the dosage of rosin gum is 1-6%.

[0013] Furthermore, a type of unbleached bamboo fiber paper cup base paper is provided, wherein the unbleached paper cup base paper is prepared by the aforementioned preparation method. The unbleached paper cup base paper has a three-layer composite structure, with the top and bottom layers being bamboo chemical pulp and the core layer being laccase / ABTS modified bamboo chemical thermomechanical pulp.

[0014] The present invention has the following advantages: This invention discloses a method for preparing all-bamboo fiber base paper for paper cups. The raw materials used are bamboo chemical pulp and bamboo thermomechanical pulp, which are cheaper than wood chemical pulp and wood thermomechanical pulp. The bamboo thermomechanical pulp is treated with laccase / ABTS. Mechanical refining breaks down the fibers, exposing more lignin, which is beneficial for subsequent laccase / mediator treatment. Laccase / mediator treatment of the bamboo thermomechanical pulp can effectively improve the bonding force between pulp fibers by degrading lignin on the fiber surface, without polluting the environment. Furthermore, fewer papermaking additives are used, reducing the pollution level of papermaking wastewater. The final paper cup base paper has high bulk, physical strength, and water resistance. Detailed Implementation

[0015] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially. Example 1

[0016] Pulping treatment: Take 30 grams of oven-dried bamboo chemical pulp and bamboo chemimechanical pulp. At a pulp concentration of 10%, use a PFI refiner to refine the bamboo chemical pulp to a freeness of 40ºSR and the bamboo chemimechanical pulp to a freeness of 40ºSR.

[0017] Biological modification treatment: Bamboo chemimechanical pulp after refining was placed in a polyethylene bag. The pH was adjusted to 5 using a sodium acetate-glacial acetic acid buffer solution. First, 0.218 U / g of laccase was added to treat the pulp, and it was kneaded thoroughly. Then, 0.7% of the mediator ABTS solution was added to adjust the pulp concentration to 10%. After thorough mixing, the pulp was placed in a 60℃ constant temperature water bath for 90 minutes, kneading every 15 minutes during the process. After biological treatment, the pulp was washed using a filter until the pH was neutral and then refrigerated for later use.

[0018] Composite papermaking: The surface and bottom layers each account for 25% of the total weight, while the core layer is entirely composed of bamboo chemithermomechanical pulp, accounting for 50%. The three layers are papermade separately, with identical amounts of papermaking additives added: The pulp fibers are evenly dispersed, then 0.7% aluminum sulfate (based on oven-dry fiber weight, the same below) is added and stirred for 1 minute. The pH is then adjusted to approximately 6, followed by the addition of 2% anionic rosin gum and a reaction time of 4 minutes. Finally, 0.02% cationic polyacrylamide (CPMA) is added and stirred for 30 seconds before papermaking. After papermaking, the three layers are stacked sequentially, and the wet paper web is pressed for 15 minutes using a press, followed by drying.

[0019] The obtained paper cup base paper has a bulk thickness of 1.64 cm. 3 ·g -1 Flexural endurance 167 cycles, stiffness 12.74 mN·m, Cobb value 29.5 g·m -2 Permeability 0.96 kg·m -2 . Example 2:

[0020] Pulping treatment: Take 30 grams of oven-dried bamboo chemical pulp and bamboo chemimechanical pulp. At a pulp concentration of 10%, use a PFI refiner to refine the bamboo chemical pulp to a freeness of 40 ºSR and the bamboo chemimechanical pulp to a freeness of 40 ºSR.

[0021] Biological modification treatment: Bamboo chemimechanical pulp after refining was placed in a polyethylene bag. The pH was adjusted to 5 using a sodium acetate-glacial acetic acid buffer solution. First, 0.109 U / g of laccase was added to treat the pulp, and it was kneaded thoroughly. Then, 0.5% of the mediator ABTS solution was added to adjust the pulp concentration to 10%. After thorough mixing, the pulp was placed in a 60℃ constant temperature water bath for 120 minutes, kneading every 15 minutes during the process. After biological treatment, the pulp was washed using a filter until the pH was neutral and then refrigerated for later use.

[0022] Composite papermaking: The surface and bottom layers each account for 20% of the total weight, while the core layer is entirely composed of bamboo chemithermomechanical pulp, accounting for 60%. The three layers are papermade separately, with identical amounts of papermaking additives added. The pulp fibers are evenly dispersed. First, 1.1% aluminum sulfate is added and stirred for 1 minute. Then, the pH is adjusted to approximately 6, followed by 3% anionic rosin gum and a reaction time of 4 minutes. Finally, 0.06% cationic polyacrylamide is added and stirred for 30 seconds before papermaking. After papermaking, the three layers are stacked sequentially, and the wet paper web is pressed using a press for 15 minutes, followed by drying.

[0023] The obtained paper cup base paper has a bulk thickness of 1.75 cm. 3 ·g -1 Flexural endurance 112 cycles, stiffness 11.24 mN·m, Cobb value 17.2 g·m -2 Permeability 1.13 kg·m -2 .

[0024] In summary, this invention uses bamboo chemical pulp and bamboo thermomechanical pulp as raw materials. First, the bamboo chemical pulp fibers and bamboo thermomechanical pulp fibers are mechanically refined. Then, laccase / mediators are used to biologically treat the bamboo thermomechanical pulp fibers to obtain pulp fiber raw materials with good binding properties. Finally, using the treated bamboo chemical pulp fibers and bamboo thermomechanical pulp fibers as raw materials, sizing agents aluminum sulfate and rosin gum are added, along with retention and filtration aid cationic polyacrylamide, to produce all-bamboo fiber basic colored paper cup base paper. Therefore, it has the following advantages: Low raw material cost: Using bamboo chemical pulp and bamboo chemothermal mechanical pulp as raw materials, the price is lower than that of wood pulp. Moreover, bamboo resources are abundant, which can reduce the consumption of wood resources and alleviate the shortage of raw materials for papermaking.

[0025] Excellent paper performance: Through the synergistic effect of mechanical pulping and laccase / ABTS biomodification, it retains the high bulk of chemothermal mechanical pulping while improving the interfiber bonding force, so that the finished product has both high bulk, high physical strength (folding endurance, stiffness) and excellent water resistance (low Cobb value, low edge penetration).

[0026] Environmentally friendly and pollution-free: The bio-modification process is green and environmentally friendly, with low energy consumption and minimal fiber damage; fewer types of papermaking additives are used, reducing the degree of wastewater pollution and conforming to the industry's environmental protection development trend.

[0027] In summary, this invention can further expand the application fields of bamboo, reduce the use of wood resources, alleviate the shortage of raw material resources in my country's papermaking industry, and is of great significance to the sustainable development of my country's papermaking industry.

[0028] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a base paper for all-bamboo fiber colored paper cups, characterized in that: The method includes the following steps: (1) Pulping treatment: The bamboo chemical pulp fiber and bamboo chemical mechanical pulp fiber are mechanically pulped to achieve a freeness of 30-60°SR. (2) Biomodification treatment: The pH of the bamboo chemimechanical pulp fiber obtained in step (1) was adjusted to 4.5-5.5, and laccase and mediator ABTS were added successively. The mixture was treated at 60±5℃ for 30-180 minutes. After treatment, the mixture was washed until neutral. The amount of laccase used was 0.05-0.35 U / g and the amount of mediator ABTS used was 0.2-1.0% based on the weight of oven-dry pulp fiber. (3) Papermaking and lamination: A three-layer paper structure is adopted, wherein the top and bottom layers are composed of bamboo chemical pulp fibers obtained in step (1), and the core layer is composed of bamboo chemical mechanical pulp fibers processed in step (2); the core layer accounts for 30-60% of the total mass of the three-layer paper, and the top and bottom layers are equal in mass; the three layers are made separately. During papermaking, aluminum sulfate is first added to the pulp and stirred to adjust the pH to 5.5-6.5, then anionic rosin gum is added to react, and finally cationic polyacrylamide is added and stirred before papermaking; the three wet paper webs are wet-laminated, pressed, and finally dried to obtain the all-bamboo fiber basic colored paper cup base paper.

2. The method for preparing a base paper for all-bamboo fiber colored paper cups according to claim 1, characterized in that: In step 1, the bamboo chemical pulp and bamboo chemimechanical pulp are ground to a beating degree of 30-60ºSR at a pulp concentration of 5-15% using a pulp refiner.

3. The method for preparing a base paper for all-bamboo fiber colored paper cups according to claim 1, characterized in that: The bamboo chemimechanical pulp in step 1 is a bamboo chemithermomechanical pulp.

4. The method for preparing a base paper for all-bamboo fiber colored paper cups according to claim 1, characterized in that: Step 2 is described in detail below: Biological modification treatment: Take refined bamboo chemimechanical pulp and adjust the pH to 4.5-5.55 with sodium acetate-glacial acetic acid buffer solution; then add laccase to treat the pulp, knead it evenly, and then add mediator solution to adjust the pulp fiber concentration to 5-15%; after mixing evenly, treat it in a constant temperature water bath at 60±5℃ for 30-180 minutes, kneading it once every 15 minutes during the process; after the treatment, wash it with a filter until neutral and refrigerate it for later use; Among them, based on the weight of oven-dry pulp fiber, the amount of laccase is 0.05-0.35 U / g pulp fiber, and the amount of mediator ABTS is 0.2-1.0%.

5. The method for preparing a base paper for all-bamboo fiber colored paper cups according to claim 1, characterized in that: In step 3, the amount of cationic polyacrylamide (a retention and filtration aid) is 0.02-0.1%, the amount of aluminum sulfate is 0.5-2.5%, and the amount of rosin gum is 1-6%, based on the weight of oven-dry pulp fibers.

6. A type of unbleached bamboo fiber paper cup base paper, characterized in that: The unbleached paper cup base paper is prepared by the preparation method according to any one of claims 1-5. The unbleached paper cup base paper has a three-layer composite structure, with the top and bottom layers being bamboo chemical pulp and the core layer being laccase / ABTS modified bamboo chemical thermomechanical pulp.