Preparation method of low-basis-weight high-strength leather paper

Abstract

The invention discloses a preparation method of low-basis-weight high-strength paper, and belongs to the technical field of pulping and papermaking pretreatment, and the key point of the technical scheme of the preparation method comprises the following steps: 1) taking fresh paper mulberry skin, stripping the skin, cleaning and cutting into sections; 2) soaking the cleaned broussonetia papyrifera bark in a mixed enzyme solution for 48 hours, wherein the mixed enzyme solution comprises xylanase and pectinase; (3) draining the soaked broussonetia papyrifera bark, cleaning, and cooking in a 10% CaO solution at 100 DEG C for 24 hours; (4) bleaching the steamed broussonetia papyrifera bark with H2O2, and cleaning for later use; 5) inactivating the filtrate subjected to enzyme treatment, filtering, and further evaporating and concentrating the filtrate to obtain a thick liquid with certain viscosity; and 6) carrying out tile beating on the obtained bleached leather pulp, and then adding the obtained viscous solution to carry out leather paper making. According to the method, the high-strength leather paper is prepared by adopting an enzyme combined chemical treatment method, and sugar and bioactive substances obtained from enzymatic hydrolysate have good viscosity and can be used as a binder of subsequent paper.

Description

Technical Field

[0001] The present invention relates to a method for preparing leather paper, and more particularly to a method for preparing handmade leather paper from bast raw materials. Background Art

[0002] Bark fiber is an important natural resource with broad application prospects. Bark bast fiber offers significant advantages in pulping, including abundant resources, high fiber strength, unique chemical composition, and environmental friendliness. Advances in modern technology have opened up new possibilities for bark pulping. While traditional bark processing is indeed complex, recent advances in biotechnology and chemical processes have made fiber extraction from bark more efficient. For example, the use of bioenzymes can effectively degrade pectin and hemicellulose in bark, improving fiber separation efficiency. High-pressure steaming and microwave pretreatment technologies have also greatly simplified the bark processing process, reducing energy consumption and chemical usage. As a representative example of the traditional paper industry, bark paper has enormous potential for numerous applications. However, traditional bark processing is complex, and the use of large amounts of chemicals increases environmental pollution. Therefore, a rapid and environmentally friendly method for preparing bast fiber bark paper is urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing low-weight, high-strength leather paper with a simple process, low chemical consumption and reduced wastewater pollution in response to the above-mentioned shortcomings of the prior art.

[0004] The technical solution of the present invention is as follows:

[0005] A method for preparing low-weight, high-strength leather paper comprises the following steps:

[0006] 1) Take fresh paper mulberry bark, peel it, wash it and cut it into sections;

[0007] 2) Soak the washed paper mulberry peel in a mixed enzyme solution containing xylanase and pectinase for 48 hours;

[0008] 3) Drain the soaked paper mulberry peels, rinse them, and steam them in a 10% CaO solution at 100°C for 24 hours.

[0009] 4) After steaming, the paper mulberry bark is bleached with H2O2 and then washed and set aside.

[0010] 5) inactivating the enzyme-treated filtrate, filtering it, and further evaporating and concentrating the filtrate to obtain a thick liquid with a certain viscosity;

[0011] 6) The bleached leather pulp obtained above is subjected to wall-pulping and then the obtained viscous solution is added to make leather paper.

[0012] The above-mentioned method for preparing low-weight and high-strength leather paper is characterized in that the bark used in step (1) is one of paper mulberry, mulberry and Chinese celtis sinensis.

[0013] The above-mentioned method for preparing low-weight and high-strength leather paper is characterized in that the bark used in step (1) is one of paper mulberry, mulberry and Chinese celtis sinensis.

[0014] The above-mentioned method for preparing low-weight high-strength leather paper is characterized in that: in step (1), the size of the leather segment after cutting is 5 cm*1 cm.

[0015] The above-mentioned method for preparing low-quantity high-strength leather paper is characterized in that: in step (2), the mixed enzyme solution is xylanase and pectinase, with concentrations of 100u / ml and 150u / ml respectively, and the soaking is carried out at room temperature using neutral deionized water.

[0016] The above-mentioned method for preparing low-weight high-strength leather paper is characterized in that: in step (3), the leather material and the CaO solution react according to a solid-liquid ratio of 1:10.

[0017] The above-mentioned method for preparing low-weight high-strength leather paper is characterized in that: in step (4), the H2O2 bleaching is carried out according to a solid-liquid ratio of 1:10, first using 0.2% DTPA+3% NaOH+2% Na2SO3 for chelation at room temperature for 20 minutes, and then adding 5% H2O2 and reacting at 90°C for 90 minutes.

[0018] The above-mentioned method for preparing low-quantity high-strength leather paper is characterized in that: in step (5), the enzyme solution is inactivated by boiling and heating, and after inactivation, it is filtered through a 0.22um filter membrane and then concentrated by rotary evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The prepared parchment paper. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are any processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0021] Example 1

[0022] 1) Take fresh paper mulberry bark, peel it, wash it and cut it into sections;

[0023] 2) Soak the washed paper mulberry peels in a mixed enzyme solution for 48 hours. The mixed enzyme solution includes xylanase and pectinase at concentrations of 100u / ml and 150u / ml, respectively. The soaking is carried out at room temperature in neutral deionized water.

[0024] 3) Drain the soaked paper mulberry peels, rinse them, and steam them in a 10% CaO solution at 100°C for 24 hours.

[0025] 4) The steamed paper mulberry peels were bleached with H2O2 and then washed for later use. The H2O2 bleaching was performed at a solid-to-liquid ratio of 1:10. First, chelation was performed using 0.2% DTPA + 3% NaOH + 2% Na2SO3 at room temperature for 20 minutes, followed by the addition of 5% H2O2 and reaction at 90°C for 90 minutes.

[0026] 5) The filtrate after enzyme treatment is inactivated at high temperature and then filtered, and the filtrate is further evaporated and concentrated to obtain a thick liquid with a certain viscosity;

[0027] 6) The bleached leather pulp obtained above is subjected to wall-pulping and then the obtained viscous solution is added to make leather paper.

[0028] Example 2

[0029] The process was carried out in accordance with Example 1, except that the enzyme solution soaking in step 2 was replaced with a 5% NaOH solution at 80° C. for 60 min, and the sugar viscosity solution obtained in Example 1 was added to make paper.

[0030] Example 3

[0031] The process was carried out in accordance with Example 1, except that the viscous sugar solution was not added during the papermaking process in step 6.

[0032] Comparative Example 1

[0033] 1) Take fresh paper mulberry bark, peel it, wash it and cut it into sections;

[0034] 2) Soak the washed paper mulberry peels in a mixed enzyme solution for 48 hours. The mixed enzyme solution includes xylanase and pectinase at concentrations of 100u / ml and 150u / ml, respectively. The soaking is carried out at room temperature in neutral deionized water.

[0035] 3) Drain the soaked paper mulberry peels, rinse them, and steam them in a 10% CaO solution at 100°C for 24 hours.

[0036] 4) The steamed paper mulberry peels were bleached with H2O2 and then washed for later use. The H2O2 bleaching was performed at a solid-to-liquid ratio of 1:10. First, chelation was performed using 0.2% DTPA + 3% NaOH + 2% Na2SO3 at room temperature for 20 minutes, followed by the addition of 5% H2O2 and reaction at 90°C for 90 minutes.

[0037] 5) The bleached leather pulp obtained above is beaten with a wall-pulper and then starch solution is added to make leather paper.

[0038] The tensile strength and tear resistance of the paper obtained above were measured, and the paper basis weight was measured in a national standard constant temperature and humidity laboratory, and physical index tests were also conducted. The pulp tensile index was measured according to GB / T453-2002, and the pulp tear index was measured according to GB / T455-2002:

[0039] Table 1: Paper strength analysis for different treatment cases

[0040] Example 1 Example 2 Example 3 Comparative Example 1 Dry tensile strength (KN / m) 1256 852 984 1082 Tear strength (mN) 675 328 465 508

[0041] As shown in Table 1, the dry tensile strength of the paper obtained in Example 1 was significantly higher than that of the other Examples and Comparative Examples. The sugar filtrate obtained from the surface enzyme treatment has high viscosity and can be used to strengthen the bond between sheets of paper. In contrast, Example 2 used a high-temperature alkali treatment for degumming, which, while removing pectin and hemicellulose, also caused some damage to the fibers, thereby reducing some of the paper's performance. Furthermore, Example 3 omitted the addition of a viscous liquid during the papermaking process, resulting in reduced paper performance. In Comparative Example 1, the addition of a starch solution as a paper binder improved paper performance to some extent, but still remained lower than the sugar solution obtained in Example 1.

[0042] The above embodiments are only preferred implementation modes of the present invention and are only used to explain the present invention rather than to limit the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for preparing low-weight high-strength leather paper, characterized in that The steps include: 1) Take fresh paper mulberry peel, peel it, wash it and cut it into sections; 2) Soak the washed paper mulberry peel in a mixed enzyme solution for 48 hours, the mixed enzyme including xylanase and pectinase; 3) After soaking, drain the water from the paper mulberry bark, wash it, and cook it in a 10% CaO solution at 100°C. 24h； 4) After steaming, the mulberry bark is bleached with H2O2 and then washed and set aside 5) inactivating the filtrate after the enzyme treatment, filtering it, and further evaporating and concentrating the filtrate to obtain a thick liquid with a certain viscosity; 6) The bleached leather pulp obtained above is subjected to wall-pulping and then the obtained viscous solution is added to make leather paper.

2. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: The bark used in step (1) is one of paper mulberry, mulberry and celtis sinensis.

3. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: After cutting in step (1), the size of the leather segment is 5cm*1cm.

4. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: In step (2), the mixed enzyme solution is xylanase and pectinase, with concentrations of 100u / ml and 150u / ml respectively. The immersion is carried out at room temperature using neutral deionized water.

5. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: In step (3), the leather material and the CaO solution react at a solid-liquid ratio of 1:

10.

6. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: In step (4), the H2O2 bleaching is carried out at a solid-liquid ratio of 1:10, first using 0.2% DTPA+3% NaOH+2% Na2SO3 for chelation at room temperature for 20 minutes, and then adding 5% H2O2 to react at 90°C for 90 minutes.

7. The method for preparing low-weight and high-strength leather paper according to claim 1, characterized in that: In step (5), the enzyme solution is inactivated by boiling and heating, and after inactivation, it is filtered using a 0.22 um filter membrane and then concentrated by rotary evaporation.

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