Papermaking method using waste grape branches as raw materials

Abstract

The invention discloses a papermaking method taking waste grape branches as raw materials. The papermaking method comprises the following steps: (1) cutting back branches: cutting back all sections of annual grape branches; (2) peeling: soaking the cut-back branches in alkali liquor for 48 hours, then taking out the branches, cleaning the branches with clear water, and peeling off barks to obtain peeled branches; (3) cooking: cooking the peeled branches in a reaction kettle containing sodium sulfide and sodium hydroxide liquid, and taking out a softened material after cooking is completed. And (4) pulping and papermaking: washing the boiled softened material to be neutral, and then pulping and papermaking to prepare paper. According to the method, the cooking temperature is controlled through a sulfate cooking method, resource reutilization of waste in the vineyard is achieved, and the method has important significance in promoting healthy and sustainable development of the grape and wine industry.

Description

Technical Field

[0001] The invention relates to the technical field of papermaking, in particular to a papermaking method using discarded grape branches as raw materials. Background Art

[0002] Cultivated grapes belong to the genus Vitis (Vmis L.) of the Vitaceae family (Vitacene Juss.). They are perennial woody vines or climbing shrubs. Pruning new shoots is essential for maintaining a certain yield and quality. A global survey of vineyard waste biomass from the grape and wine industry indicates that at least 6.73-18.59 million tons of vineyard winter pruning waste is generated annually, with annual pruning waste accounting for over 90% of this waste. Many farmers and grape growers dispose of this waste by incineration to reduce costs, resulting in significant environmental pollution. Effectively treating this waste has become a pressing issue for the industry. Vineyard winter pruning waste, such as annual grape pruning waste, is a vast agricultural resource. It is composed of cellulose, hemicellulose, and lignin, as well as crude protein, crude fat, minerals, and other bioactive compounds.

[0003] Therefore, if vineyard waste can be effectively transformed and utilized, replacing traditional extensive processing, it will not only have positive economic benefits but also contribute to the green and sustainable development of the wine industry. Currently, some researchers are experimenting with using winter pruning waste as fertilizer or feed, but the overall effectiveness of this utilization remains to be explored. In grape and wine production, grape bagging, wine labeling, and other types of grape and wine packaging all require significant amounts of paper.

[0004] Therefore, establishing a method for making paper from discarded grape branches and using it for wine packaging to achieve resource recycling of vineyard waste is of great significance for promoting the healthy and sustainable development of the grape and wine industry. Summary of the Invention

[0005] In view of this, the present invention provides a papermaking method using discarded grape branches as raw materials.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A papermaking method using discarded grape branches as raw materials comprises the following steps:

[0008] (1) Pruning: Remove non-fibrous impurities (such as soil, leaves, etc.) from the winter-pruned grape branches and prune them at all nodes of the one-year-old grape branches;

[0009] (2) Peeling: After pruning according to the internodes, soaking in alkali solution to remove the epidermis, and washing to obtain peeled branches;

[0010] (3) Steaming and calculating the yield: the peeled branches are mixed with a liquid containing sodium sulfide and sodium hydroxide, and steamed in a microwave reactor at a set insulation temperature and alkali amount; after the steaming is completed, the softened material is taken out, dried in a constant temperature oven, and the yield is calculated.

[0011] (4) Pulping and papermaking: The softened material after cooking is washed, pulped, and made into paper.

[0012] Preferably, in step (1), the annual grape branches must be pruned at the nodes to facilitate subsequent peeling.

[0013] Preferably, in step (2), the bark of the pruning branches must be removed. The epidermis of grape branches plays a protective role. After maturation and drying, it becomes bark that is easily peeled off, which is one of the important characteristics that distinguishes grape branches from other fruit tree branches. Removing the bark can reduce the lignin content and reduce the consumption of chemical reagents in subsequent experiments.

[0014] Preferably, in step (2), the alkali solution is a 2% NaOH solution, the soaking time is 48 hours, and after rinsing to neutrality, the peeling process is simple.

[0015] Preferably, in step (3), cooking is carried out in a microwave reactor at a holding temperature of 150° C.-170° C., the degree of sulfidation is 25%, the amount of alkali used is 15%-20%, and the holding time is 120 minutes.

[0016] Preferably, the optimal process parameters for the cooking are: holding temperature 160±2° C., alkali dosage 20±2%, sulfidation degree 25%, and holding time 120 minutes.

[0017] Preferably, in step (3), the mixture is dried in a constant temperature oven at 37° C. for 24 hours.

[0018] Preferably, in step (4), the pulping is performed using a trough-type Wally pulper, and the pulping time is 5000 times counted by the equipment.

[0019] Preferably, in step (4), papermaking includes the steps of pneumatic stirring, rapid drainage, vacuum dehydration and vacuum drying and shaping.

[0020] Preferably, the performance indicators of the paper are: average maximum tensile strength of 6.7965 N / m, average surface contact angle of 14.997°, average maximum folding endurance of 3.33 times, and uniform fiber structure distribution in microscopic morphology without obvious impurities.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] (1) Efficient resource utilization: The present invention utilizes discarded grape branches as papermaking raw materials, thereby solving the resource waste and environmental pollution problems caused by the large-scale discard or incineration of grape branches, and realizing the efficient conversion and resource utilization of agricultural waste;

[0023] Compared with traditional papermaking raw materials, grape branches are widely available, low-cost, and have good fiber properties, providing a new raw material option for the papermaking industry;

[0024] (2) Good application prospects: The paper produced has a unique yellow-brown appearance and good original texture, and is suitable for special purposes such as wine labels and wrapping paper;

[0025] (3) The maximum tensile strength of the paper of the present invention reaches 679.65 N / m, which can meet general writing and packaging needs;

[0026] (4) The paper of the present invention has strong hydrophilicity and a surface contact angle of only 14.997°, making it suitable for printing and writing, and can achieve anti-counterfeiting function by adding fluorescent reagents;

[0027] (5) The present invention can be used to produce wine labels, special packaging paper, etc. It has broad market prospects and can bring significant economic benefits to enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 and Figure 2 The actual picture of the paper produced by the method of the present invention and the picture observed under a microscope; it can be seen that the paper has a natural yellow-brown color and good texture; and under the microscope, it has uniform fiber distribution and no impurities;

[0029] Figure 3 This is a diagram showing the printing effect of the paper of the present invention on a commercially available printer; it can be seen that the text is clear, proving that the writing and printing properties of the paper are good.

[0030] Figure 4 This is a schematic diagram of the fluorescent anti-counterfeiting paper of the present invention; it demonstrates the fluorescent anti-counterfeiting effect achieved by adding 2% fluorescent reagent during the papermaking process. Under ultraviolet light, the paper surface clearly displays the fluorescent number "29," which can be used in anti-counterfeiting designs for products such as wine labels. See Example 2 for details. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] 1) Raw material pretreatment

[0033] Branch collection and sorting: Remove non-fibrous impurities (such as soil and leaves) from discarded grape branches, prune them at intervals of winter buds, and leave the internodes of the grape branches;

[0034] Peeling: Soak the grape branches in lye, then wash and remove the skin after 48 hours;

[0035] 2) Cooking experiment:

[0036] Cooking experiment: Weigh two equal portions of peeled branches each time, mix one portion evenly with the medicinal solution, and place them in a microwave reactor for cooking reaction. Each experiment is performed at a pre-set holding temperature. After heating to the corresponding temperature, a countdown of 2 hours is set. When the timer ends, remove the softened material, filter and wash it until it is neutral, and then dry it in a 37°C constant temperature oven for 24 hours. Weigh the net mass after drying, and record the data.

[0037] Calculate the yield: Weigh the same mass of peeled wood chips as the steamed wood chips in each test group and dry them under the same conditions; calculate the ratio of the steamed wood after drying to the same mass of the unsteamed wood after drying to calculate the yield under each pulping condition;

[0038] The yield experimental results are shown in Table 1;

[0039] Table 1: Cooking experiment results

[0040]

[0041] 3) Pulping and papermaking

[0042] The dried grape branch fibers were fed into an IMT-VL01A laboratory trough-type Valli pulper for refining, with the refining time being 5000 machine counts. The refined pulp was then subjected to pneumatic stirring, rapid drainage, vacuum dehydration, vacuum drying and shaping in an integrated papermaking machine to produce paper.

[0043] 4) Paper performance test

[0044] Mechanical tensile strength test: The specimen is clamped between the upper and lower clamps of a universal tensile testing machine. The tensile speed is set to 10 mm / min. High-precision force sensors and displacement sensors are used to collect real-time tensile force-elongation data until the specimen breaks. The collected data is processed and a tensile force-deformation curve is plotted to obtain the maximum deformation percentage and maximum tensile strength.

[0045] Surface contact angle test: The sample is fixed on the sample stage of the SGC-B3 contact angle meter to ensure the surface is flat. Deionized water is dripped onto the paper surface using a microsyringe. When the droplet forms, a high-resolution camera is activated to capture the droplet's contour image. The left and right contact angles are calculated using a three-point fitting method for circular fitting. The average of three parallel measurements is taken as the final contact angle measurement result.

[0046] Maximum folding endurance test: Secure the specimen in the fixture of an IMT-205A paper folding tester. Using standard weights, precisely adjust the tension to 4.91N. Start the tester and set the folding angle to 135 degrees. When the specimen completely breaks, the tester automatically stops and records the number of folds. The average of three parallel measurements is the maximum folding endurance.

[0047] Microscopic observation: Place the finished paper sample on the stage of an optical microscope. Use the SEMS software to observe the microscopic image under the combination of a 10× eyepiece and a 40× objective lens, focusing on the paper fiber distribution and impurity removal.

[0048] Example 1:

[0049] A papermaking method using discarded grape branches as raw materials comprises the following steps:

[0050] (1) Raw material pretreatment: discarded grape winter pruning branches were removed of non-fiber impurities, pruned according to internodes, and then soaked in 2% NaOH solution for 48 hours to remove the epidermis, and then washed to obtain peeled branches;

[0051] (2) Steaming and calculating the yield: the peeled branches were mixed with a solution containing sodium sulfide and sodium hydroxide, and steamed in a microwave reactor at a temperature of 150°C–170°C and an alkali content of 15%–20%. The sulfidation degree was 25% and the heat preservation time was 120 minutes. After the steaming was completed, the softened material was taken out and dried in a constant temperature oven at 37°C for 24 hours and the yield was calculated.

[0052] (3) Pulping and papermaking: The softened material after cooking is washed and refined using a trough-type Wally pulper for 5,000 times. The paper is then made by pneumatic stirring, rapid drainage, vacuum dehydration, and vacuum drying.

[0053] The performance indicators of the paper are: average maximum tensile strength 6.7965N / m, average surface contact angle 14.997°, and average maximum folding endurance 3.33 times.

[0054] Example 1:

[0055] (1) Raw material pretreatment: discarded grape winter pruning branches were removed of non-fiber impurities, pruned according to internodes, and then soaked in 2% NaOH solution for 48 hours to remove the epidermis, and then washed to obtain peeled branches;

[0056] (2) Steaming and calculating the yield: 100 g of grape branches were pretreated and steamed under the conditions of 25% sulfidation, 20% alkali (NaOH), 120 min of holding time, 160°C of holding temperature, and 2 h of holding time; after steaming, the softened material was taken out and dried in a constant temperature oven at 37°C for 24 h, and the yield was calculated;

[0057] (3) Pulping and Papermaking: The softened material after cooking is washed and refined using a trough-type Wally beater for 5,000 counts. The paper is then pneumatically stirred, rapidly drained, vacuum dehydrated, and vacuum dried to form the paper. The average maximum deformation percentage of the paper obtained is 1.723%, the average maximum tensile strength is 679.65 N / m, the average surface contact angle is 14.997°, the average maximum folding endurance is 3.33 times, and the fiber structure is evenly distributed in the microscopic morphology without obvious impurities.

[0058] Example 2:

[0059] (1) Raw material pretreatment: discarded grape winter pruning branches were removed of non-fiber impurities, pruned according to internodes, and then soaked in 2% NaOH solution for 48 hours to remove the epidermis, and then washed to obtain peeled branches;

[0060] (2) Steaming and yield calculation: 100 g of grape branches were pretreated and steamed under the following conditions: a 25% sulfidation degree, 15% alkali (NaOH), a holding time of 120 min, a holding temperature of 160°C, and a holding time of 2 h. After steaming, the softened material was removed and dried in a constant temperature oven at 37°C for 24 h, and the yield was calculated.

[0061] (3) Pulping and papermaking: The softened material after cooking is washed and pulped using a trough-type Wally pulper for 5,000 times. The paper is then pneumatically stirred, rapidly drained, vacuum dehydrated, and vacuum dried to form the paper. The average maximum deformation percentage of the paper obtained is 0.854%, the average maximum tensile strength is 219 N / m, the average surface contact angle is 40.206°, and the average maximum folding endurance is 18 times. Microscopic observation shows that some lignin has not been completely removed.

[0062] Cooking experiment results:

[0063] By comparing the cooking yields under different holding temperatures and alkali dosages, it was found that when the holding temperature was 160°C and the alkali dosage was 20%, the pulp yield was the highest, reaching 38.13%.

[0064] Paper performance test results:

[0065] The properties of paper prepared under the optimal cooking conditions (160°C, 20% alkali dosage) are as follows:

[0066] Maximum tensile strength: 679.65N / m, significantly higher than traditional wheat straw paper (about 200N / m).

[0067] The maximum deformation percentage is 1.723%, showing good flexibility.

[0068] The surface contact angle is 14.997°, indicating strong hydrophilicity and suitable for printing and writing. The method according to claim 1 is characterized in that, in step (3), 2% fluorescent reagent is added during the papermaking process to produce paper with fluorescent anti-counterfeiting properties, thereby achieving fluorescent anti-counterfeiting for wine labels.

[0069] Maximum folding endurance: 3.33 times, which is lower than traditional paper (about 10 times or more), but can meet general packaging and writing needs.

[0070] Microscopic morphology observation: The fiber structure is evenly distributed in the microscopic morphology, without obvious impurities.

[0071] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A papermaking method using discarded grape branches as raw materials, characterized in that: The steps include: (1) Pruning: Remove non-fibrous impurities (such as soil, leaves, etc.) from the winter-pruned grape branches and prune them at all nodes of the one-year-old grape branches; (2) Peeling: After pruning according to the internodes, soaking in alkali solution to remove the epidermis, and washing to obtain peeled branches; (3) Steaming: The peeled branches are placed in a reactor containing sodium sulfide and sodium hydroxide solution for steaming, and the softened material is taken out after the steaming is completed; (4) Pulping and papermaking: The softened material after cooking is washed to neutrality, and then pulped and papered to make paper.

2. The method according to claim 1, characterized in that In the step (2), the alkali solution is a 2% NaOH solution, the soaking time is 48 hours, all the branches are immersed in the alkali solution, and the surface of the branches is rinsed with clean water until the alkali solution is neutral.

3. According to the method of claim 1, the bark of the pruned branches must be removed. The epidermis of grape branches plays a protective role. After maturation and drying, it turns into bark, which is easy to peel off. It is one of the important characteristics that significantly distinguishes grape branches from other fruit trees. Removing the bark can reduce the lignin content and reduce the consumption of chemical reagents in subsequent experiments.

4. The papermaking method using discarded grape branches as raw materials according to claim 1, characterized in that: In the step (3), cooking is carried out at a temperature of 150° C. to 170° C., the cooking liquid is (sulfurization degree is 25%, the amount of alkali is 15% to 20%), and the cooking time is 120 minutes.

5. The papermaking method using discarded grape branches as raw materials according to claim 4, characterized in that: The optimal process parameters of the cooking are: holding temperature 160±2° C., alkali dosage 20±2%, sulfidation degree 25%, and holding time 120 minutes.

6. The papermaking method using discarded grape branches as raw materials according to claim 1, characterized in that: In the step (4), the pulping is performed using a trough-type Wally pulper, and the pulping time is 5000 times counted by the equipment.

7. The papermaking method using discarded grape branches as raw materials according to claim 1, characterized in that: In the step (4), papermaking includes the steps of pneumatic stirring, rapid drainage, vacuum dehydration and vacuum drying and shaping.

8. The papermaking method using discarded grape branches as raw materials according to claim 1, characterized in that: The performance indicators of the paper are: average maximum tensile strength of 6.7965 N / m, average surface contact angle of 14.997°, average maximum folding endurance of 3.33 times, and under microscopic observation, the fiber structure is evenly distributed without obvious impurities.

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