Method for efficiently increasing the water retention value of chemi-mechanical pulp waste paper fibers

Abstract

The application belongs to the field of increasing the water retention value of chemical pulp waste paper fibers, and discloses a method for efficiently increasing the water retention value of chemical pulp waste paper fibers, which comprises the following preparation steps: firstly, mixing chemical pulp waste paper fibers with pentaerythritol; then, adding a certain amount of acetylcholine and acetic acid in sequence; after being mixed uniformly, heating treatment is performed, the pretreatment temperature and time are controlled, and after the treatment is completed, an ethanol solution is added to terminate the reaction, so that modified waste paper pulp fibers are obtained. The application has the advantages of short time, simple process, mild conditions, simple steps, easy operation and suitability for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of waste paper pulp performance improvement, and specifically relates to a method for efficiently increasing the water retention value of waste paper pulp fibers. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In recent years, due to the shortage of fiber raw materials and rising environmental awareness, the recycling of waste paper fibers has received increasing attention. Globally, the consumption and proportion of waste paper fibers have shown a year-on-year increasing trend. Realizing the recycling and utilization of waste paper fibers can effectively solve problems such as raw material shortages and environmental pollution. Furthermore, as a pillar industry of the national economy, the recycling and utilization of waste paper fibers is an essential path to achieving sustainable development in the paper industry and an important measure for building a green and ecological civilization. However, with the increase in the number of times waste paper is recycled, the cell walls of waste paper fibers undergo irreversible changes, resulting in a decrease in fiber swelling; this change is called keratinization. The degree of fiber swelling can be expressed by the fiber's water retention value, reflecting the degree of fibrillation and the strength of the bonds between fibers. Studies have confirmed that the cell cavities of keratinized fibers are compacted or crushed, causing the fibers to become harder, reducing the water retention value, and decreasing the physical strength properties of the finished paper.

[0004] On the other hand, chemimechanical pulping has many advantages such as high yield, low pollution, and low energy consumption, which can meet the needs of the rapidly developing paper industry. This pulping method has developed rapidly in recent decades. The proportion of chemimechanical pulp in waste paper fibers is also increasing. Therefore, it is crucial to explore an efficient method to increase the water retention value of chemimechanical pulp waste paper fibers.

[0005] Existing methods for improving the water retention value of waste paper fibers mainly include bio-enzyme treatment, mechanical pulping, and chemical modification. Among these methods, bio-enzyme treatment has drawbacks such as strict process requirements, long processing cycles, and difficulty in large-scale application; mechanical pulping has drawbacks such as high energy consumption and severe fiber damage; and the use of chemical reagents in chemical modification processes generates a large amount of wastewater, increasing the pressure on water pollution treatment and making it not a green and environmentally friendly method. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A first aspect of the present invention provides a method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers, comprising:

[0009] The chemimechanical pulp waste paper fiber was mixed evenly with pentaerythritol, and then acetylcholine and acetic acid were added. After mixing evenly, the mixture was heated. After the treatment was completed, the reaction was terminated to obtain the modified waste paper pulp fiber.

[0010] In some embodiments, the source of the chemimechanical pulp waste paper fiber is pulp obtained from coniferous wood, broadleaf wood and non-wood raw materials through various chemimechanical pulping processes;

[0011] In some embodiments, the lignin content in the chemimechanical pulp waste paper fiber is 15-20%;

[0012] In some embodiments, the moisture content of the chemimechanical pulp waste paper fibers is 1-5%;

[0013] In some embodiments, the whiteness of the chemimechanical pulp waste paper fibers is 45-55% ISO;

[0014] In some embodiments, the molecular weight of lignin in the chemimechanical pulp waste paper fibers is between 3000 and 4500. In some embodiments, the mass ratio of the chemimechanical pulp waste paper fibers to pentaerythritol is 1:0.01 to 0.015.

[0015] In some embodiments, the mass ratio of acetylcholine to chemimechanical pulp waste paper fiber is 1:20 to 30.

[0016] In some embodiments, the mass ratio of acetylcholine to acetic acid is 1:0.01 to 0.02.

[0017] In some embodiments, the concentration of pentaerythritol is 95-96%;

[0018] In some embodiments, the concentration of acetylcholine is 95-98%;

[0019] In some embodiments, the concentration of the acetic acid is 95-99%.

[0020] In some embodiments, the heat treatment temperature is 55–70°C and the treatment time is 20–50 min.

[0021] In some embodiments, an ethanol solution is added to terminate the reaction after the treatment is completed, and the volume-to-mass ratio of the ethanol solution to the chemimechanical waste paper pulp fiber is 1:0.5 to 1.0.

[0022] In some embodiments, the temperature of the ethanol solution is 4–10°C;

[0023] In some embodiments, the concentration of the ethanol solution is 10-20%.

[0024] More specifically, including:

[0025] First, chemimechanical pulp waste paper fibers are thoroughly mixed with pentaerythritol. Then, acetylcholine and acetic acid are added, and the mixture is thoroughly mixed again before undergoing water bath heating treatment. After a certain period of treatment, the reaction is terminated to obtain modified waste paper fibers. The specific process is as follows: First, chemimechanical pulp waste paper fibers are thoroughly mixed with pentaerythritol; then, a certain amount of acetylcholine and acetic acid are added sequentially; after thorough mixing again, the mixture is heated, and the pretreatment temperature and time are controlled. After the treatment is completed, an ethanol solution is added to terminate the reaction to obtain modified waste paper pulp fibers.

[0026] In a second aspect, the present invention also provides modified waste paper pulp fibers prepared by the above-described method.

[0027] A third aspect of the present invention also provides the application of the modified waste paper pulp fiber prepared by the above method in the fields of papermaking, synthetic fibers, plastics, and chemicals.

[0028] Beneficial effects of the present invention

[0029] (1) The method of the present invention has the advantages of short time and simple process, and is a green and environmentally friendly approach;

[0030] (2) The method of the present invention has mild conditions, simple steps, is easy to operate, and is suitable for industrial production;

[0031] (3) The method of the present invention is beneficial to improving the water absorption and swelling capacity of waste paper fibers and realizing the effective recovery of the performance of waste paper fibers. Detailed Implementation

[0032] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0034] In the following examples, poplar chemimechanical pulp waste paper fiber, wheat straw chemimechanical pulp waste paper fiber, and eucalyptus chemimechanical pulp waste paper fiber are all commercially available products, as are all other raw materials and reagents.

[0035] Example 1

[0036] Poplar chemimechanical pulp waste paper fiber (lignin content 15%; moisture content 2%; whiteness 55% ISO; lignin molecular weight 3200) was taken and thoroughly mixed with pentaerythritol. Then, a certain amount of acetylcholine and acetic acid were added in sequence. After thorough mixing again, the mixture was heated and the pretreatment temperature and time were controlled. After the treatment was completed, an ethanol solution was added to terminate the reaction, and the modified waste paper pulp fiber was obtained. The specific process and treatment conditions are as follows: the mass ratio of poplar chemimechanical pulp waste paper fiber to pentaerythritol is 1:0.01; the concentration of pentaerythritol is 96%; the mass ratio of acetylcholine to acetic acid is 1:0.01; the concentration of acetylcholine is 95%; the concentration of acetic acid is 99%; the mass ratio of acetylcholine to poplar chemimechanical pulp waste paper fiber is 1:25; after thorough mixing, the temperature for heating treatment is 65℃, and the treatment time is 40 minutes; the volume-to-mass ratio of ethanol solution to poplar chemimechanical pulp waste paper fiber is 1:0.5; the temperature of the ethanol solution is 4℃; and the concentration of the ethanol solution is 15%.

[0037] Table 1. Various indicators of poplar chemical pulp waste paper pulp fiber before and after treatment.

[0038]

[0039]

[0040] As shown in Table 1, after treatment using this method, the water retention value of poplar chemimechanical pulp fiber increased from 120% to 260%, the tensile index of the paper increased from 15.22 N·m / g to 20.33 N·m / g, and the tear index of the paper increased from 3.26 mN·m / g. 2 / g increased to 4.83mN·m 2 / g. The above results confirm that this method can effectively increase the water retention value of poplar chemimechanical pulp waste paper fibers and the physical strength of the finished paper.

[0041] Example 2

[0042] Take wheat straw chemimechanical pulp waste paper fiber (lignin content 20%; moisture content 5%; whiteness 45% ISO; lignin molecular weight 4500), mix it thoroughly with pentaerythritol; then, add a certain amount of acetylcholine and acetic acid in sequence; mix thoroughly again and heat it, adjust the pretreatment temperature and time, and add ethanol solution to terminate the reaction after treatment to obtain modified waste paper pulp fiber. The specific process and treatment conditions are as follows: the mass ratio of straw-based mechanical pulp waste paper fiber to pentaerythritol is 1:0.015; the concentration of pentaerythritol is 95%; the mass ratio of acetylcholine to acetic acid is 1:0.02; the concentration of acetylcholine is 98%; the concentration of acetic acid is 99%; the mass ratio of acetylcholine to straw-based mechanical pulp waste paper fiber is 1:25; after thorough mixing, the temperature for heating treatment is 60℃, and the treatment time is 30 min; the volume-to-mass ratio of ethanol solution to straw-based mechanical pulp waste paper fiber is 1:1.0; the temperature of the ethanol solution is 10℃; and the concentration of the ethanol solution is 10%.

[0043] Table 2. Various indicators of straw pulp waste paper pulp fiber before and after treatment.

[0044]

[0045] Table 2 shows that, after treatment using this method, the water retention value of the wheat straw chemimechanical pulp fiber increased from 80% to 130%, the tensile index of the paper increased from 12.35 N·m / g to 16.62 N·m / g, and the tear index of the paper decreased from...

[0046] 1.68 mN·m 2 / g increased to 2.85mN·m 2 / g. The above results confirm that this method can effectively increase the water retention value of straw chemimechanical pulp waste paper fibers and the physical strength of the finished paper.

[0047] Example 3

[0048] Eucalyptus chemimechanical pulp waste paper fiber (lignin content 20%; moisture content 5%; whiteness 45% ISO; lignin molecular weight 4500) was taken and thoroughly mixed with pentaerythritol; then, a certain amount of acetylcholine and acetic acid were added in sequence; after being thoroughly mixed again, it was heated and the pretreatment temperature and time were controlled. After the treatment was completed, an ethanol solution was added to terminate the reaction, and the modified waste paper pulp fiber was obtained. The specific process and treatment conditions are as follows: the mass ratio of eucalyptus chemimetallic pulp waste paper fiber to pentaerythritol is 1:0.015; the concentration of pentaerythritol is 96%; the mass ratio of acetylcholine to acetic acid is 1:0.02; the concentration of acetylcholine is 98%; the concentration of acetic acid is 95%; the mass ratio of acetylcholine to eucalyptus chemimetallic pulp waste paper fiber is 1:30; after thorough mixing, the temperature for heating treatment is 60℃, and the treatment time is 50 min; the volume-to-mass ratio of ethanol solution to eucalyptus chemimetallic pulp waste paper fiber is 1:0.5; the temperature of the ethanol solution is 4℃; and the concentration of the ethanol solution is 10%.

[0049] Table 3. Various indicators of eucalyptus chemical pulp waste paper pulp fiber before and after treatment.

[0050]

[0051] As shown in Table 3, after treatment using this method, the water retention value of eucalyptus chemimechanical pulp fiber increased from 80% to 130%, the tensile index of the paper increased from 12.35 N·m / g to 18.62 N·m / g, and the tear index of the paper increased from 1.68 mN·m 2 / g increased to 2.85mN·m 2 / g. The above results confirm that this method can effectively increase the water retention value of eucalyptus chemimechanical pulp waste paper fibers and the physical strength of the finished paper.

[0052] Comparative Example 1

[0053] The difference from Example 1 is that pentaerythritol was replaced with methanol. The fiber water retention value was 125%, the tensile index of the paper was 15.63 (N·m / g), and the tear index of the paper was 3.29 (mN·m). 2 / g).

[0054] Comparative Example 2

[0055] The difference from Example 1 is that acetic acid was replaced with formic acid. The fiber water retention value was 130%, the tensile index of the paper was 16.32 (N·m / g), and the tear index of the paper was 3.58 (mN·m). 2 / g).

[0056] Comparative Example 3

[0057] The difference from Example 1 is that acetic acid was replaced with tartaric acid. The fiber water retention value was 150%, the tensile index of the paper was 16.25 (N·m / g), and the tear index of the paper was 3.31 (mN·m). 2 / g).

[0058] Comparative Example 4

[0059] The difference from Example 1 is that acetylcholine was replaced with choline sulfate. The fiber water retention value was 135%, the tensile index of the paper was 15.95 (N·m / g), and the tear index of the paper was 3.37 (mN·m). 2 / g).

[0060] As can be seen from the descriptions of Example 1 and Comparative Example 1, compared with methanol, the use of pentaerythritol can better improve the water retention value of chemimechanical pulp waste paper fibers, and the tensile index and tear index of the finished paper are also significantly improved.

[0061] As can be seen from the descriptions of Example 1, Comparative Examples 2 and 3, compared with formic acid and tartaric acid, acetic acid can better improve the water retention value of chemimechanical pulp fibers, and the tensile index and tear index of the paper are also significantly improved.

[0062] As can be seen from the description of Comparative Example 4 in Example 1, compared with choline sulfate, acetylcholine is used to improve the water retention value of chemimechanical pulp fibers, and the tensile index and tear index of the paper are also significantly improved.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers, characterized in that, include: The chemimechanical pulp waste paper fiber was mixed evenly with pentaerythritol, then acetylcholine and acetic acid were added. After mixing evenly, the mixture was heated. After the treatment was completed, the reaction was terminated to obtain the modified waste paper pulp fiber. The mass ratio of the chemimechanical pulp waste paper fiber to pentaerythritol is 1:0.01~0.015; The mass ratio of acetylcholine to chemimechanical pulp waste paper fiber is 1:20~30; The mass ratio of acetylcholine to acetic acid is 1:0.01~0.

02.

2. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The source of the chemimechanical pulp waste paper fiber is pulp obtained from coniferous wood, broadleaf wood and non-wood raw materials through various chemimechanical pulping processes.

3. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The lignin content in the chemimechanical pulp waste paper fiber is 15-20%.

4. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The moisture content of the chemimechanical pulp waste paper fiber is 1-5%.

5. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The whiteness of the chemimechanical pulp waste paper fiber is 45~55% ISO.

6. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The molecular weight of lignin in the chemimechanical pulp waste paper fiber is between 3000 and 4500.

7. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The concentration of pentaerythritol is 95-96%; Alternatively, the concentration of acetylcholine may be 95-98%. Alternatively, the concentration of the acetic acid is 95-99%.

8. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, The heat treatment temperature is 55~70℃, and the treatment time is 20~50 min.

9. The method for efficiently increasing the water retention value of chemimechanical pulp waste paper fibers as described in claim 1, characterized in that, After the treatment is completed, an ethanol solution is added to terminate the reaction. The volume-to-mass ratio of the ethanol solution to the chemimechanical waste paper pulp fiber is 1:0.5~1.

0. Alternatively, the temperature of the ethanol solution is 4~10℃; Alternatively, the concentration of the ethanol solution may be 10-20%.

10. Modified waste paper pulp fiber prepared by a method for efficiently increasing the water retention value of chemimechanical pulp waste paper fiber according to any one of claims 1-9.

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