CN113123158B - Water-resistant transparent paper and preparation method and application thereof - Google Patents

Abstract

The invention relates to the field of special paper manufacturing, in particular to a water-resistant transparent paper and a preparation method and application thereof. The invention provides a cellulose water-resistant transparent paper with a fiber diameter of 5nm to 999nm, the fibers are entangled with each other, and the maintenance of hydrogen bonds is independent, and still has high wet strength in water. In addition, the molecular structure of cellulose is not modified, and no refractory hydrophobic additives are introduced, which minimizes the impact on the cellulose crystal structure and maintains the performance of the cellulose-based material itself, so as to achieve a diameter as low as 5nm. The control of cellulose fibers will not cause too much influence on the transparency of the paper, and the transparency can be as high as 92%, which well achieves the balance between water resistance and transparency of cellulose paper. The water-resistant paper prepared by the invention is easily degradable, environmentally friendly, has superior performance and broad usage scenarios, and has good commercial prospects.

Description

Water-resistant transparent paper and preparation method and application thereof

technical field

The invention relates to the field of special paper manufacturing, in particular to a water-resistant transparent paper and a preparation method and application thereof.

Background technique

Paper has bright application prospects due to its abundant sources, low price, biodegradability, light weight, excellent flexibility, controllable properties, and roll-to-roll production. In recent years, with the rapid development of various manufacturing technologies and the frequent intersection of multiple disciplines, many advanced paper-based materials have been continuously developed, making paper also begin to shine in the field of electronic devices that are in great demand. Devices such as circuit boards, field emission transistors, organic solar cells, and chemical and biological sensors have been fabricated.

Transparent paper is a kind of special paper, which is widely used in labels, decoration, food packaging, construction, insulation and other fields. In the past few years, because of its excellent optical properties, mechanical properties, surface properties, extremely low thermal expansion coefficient and other advantages, transparent paper is considered to be expected to replace plastic films. Scientists have tried different methods to build various electronic devices on transparent paper. On top of that, such as displays, transistors, organic light-emitting diodes (OLEDs), lithium batteries, solar cells, and antennas, a new generation of "green" electronic devices is produced. However, because ordinary paper itself does not have water-resistant properties, and transparent paper is mostly made of nanofibers, compared with paper made of larger-scale fibers, it cannot withstand high-humidity environments. If immersed in water, it will quickly dissolve and disappear. , does not have any strength at all, which greatly limits the application scenarios of transparent paper.

The traditional water-resistant paper manufacturing methods can be mainly divided into two categories. One is to avoid direct contact between cellulose fibers and water. This type of method mainly coats or fills cellulose into fibers by introducing other hydrophobic and water-resistant additives. In between, the cellulose paper itself is not really water-resistant; the second is to modify the cellulose through regeneration, cross-linking, grafting, etc., for example, hydrophobic groups can be Alkylation, esterification and graft copolymerization are introduced to the surface of the fiber to endow the cellulose with water resistance. However, these reaction processes require the use of some organic solvents that are flammable, harmful to human health and not environmentally friendly, and additional processes will be added. Increase production costs. For another example, cellulose can also be dissolved to prepare a dispersion liquid, and a strong acid or heavy metal salt can be added after forming a gel for processing and preparation. However, the strong acid hydrolysis method is easy to cause equipment corrosion, and a large amount of waste acid is difficult to handle, which will cause various environmental problems, heavy metal salts. It will also cause serious pollution to the environment. Moreover, the reaction conditions in the above preparation methods are relatively harsh, which will have a certain impact on the crystal structure of cellulose itself, thereby causing the performance of the nanocellulose-based material to decline. Therefore, these methods are difficult to prepare very thin transparent water-resistant paper.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a water-resistant transparent paper that does not require chemical structure modification of cellulose, and does not need to introduce additional hydrophobic additives, strong acids or heavy metal salts during the preparation process, and a preparation method and application thereof.

In one aspect of the present invention, there is provided a cellulose water-resistant transparent paper. The fiber diameter of the cellulose in the cellulose water-resistant transparent paper is 5 nm to 999 nm, the fibers are entangled with each other, and the cellulose is not connected to each other. Branched hydrophobic groups, the water-resistant transparent paper does not contain additional hydrophobic additives.

The water-resistant transparent paper prepared by the invention does not modify the molecular structure of cellulose, and does not introduce refractory hydrophobic additives, so as to reduce the influence on the crystal structure of cellulose as much as possible, and maintain the performance of the cellulose-based material itself, thereby realizing The control of cellulose fibers with a diameter as low as 5nm makes the fibers intertwined and hooked up with each other through physical force, independent of the maintenance of hydrogen bonds, so they will not be attacked by water molecules, and still have high humidity in water. Strength, and will not cause too much impact on the transparency of the paper, the transparency can be as high as 92%, a good balance of water resistance and transparency of cellulose paper. In addition, after soaking, it has better abrasion resistance, burst resistance, tear resistance, folding resistance and softness than ordinary transparent paper. The water-resistant paper prepared by the invention is easy to degrade, is environmentally friendly, has superior performance and broad usage scenarios, and has good commercial prospects.

In one embodiment, the thickness of the cellulose water-resistant transparent paper ranges from 5 μm to 250 μm.

In one embodiment, the cellulose is extracted from at least one of lianas, herbs, and woody plants.

The present invention also provides a method for preparing the aforementioned cellulose water-resistant transparent paper, which comprises the following steps: immersing the cellulose transparent paper in an alkaline solution for treatment, cleaning after the treatment is completed, and then drying.

In one embodiment, the mass percentage concentration of the lye solution is 8% to 40%, and the temperature of the lye solution is greater than or equal to 8°C.

In one embodiment, the treatment time of the immersion in the alkali solution is 10 seconds to 48 hours.

In one embodiment, the alkaline solution is at least one of sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, calcium hydroxide solution, and ammonia water.

In one embodiment, the sodium hydroxide solution is an aqueous sodium hydroxide solution with a concentration of 18% to 25% by mass.

In one embodiment, the sodium hydroxide solution is a sodium hydroxide alcohol solution with a mass percentage concentration of 8% to 16%, and in the sodium hydroxide alcohol solution, the mass ratio of water and alcohol is (0.5 to 1.2 ):1.

The present invention also provides an electronic device comprising the aforementioned cellulose water-resistant transparent paper.

Description of drawings

Fig. 1 is the photo of the water-resistant transparent paper bearing 200g lead block prepared by embodiment 1;

Fig. 2 is the water-holding photo of the water-resistant paper bag prepared by the water-resistant paper prepared in Example 3;

FIG. 3 is a comparison of the changes in the fiber morphology of the transparent paper in Example 14 before and after the water-resistant treatment.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the invention, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise. In the description of the present invention, "several" means at least one, such as one, two, etc., unless expressly and specifically defined otherwise.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention provides a cellulose water-resistant transparent paper. The fiber diameter of the cellulose in the cellulose water-resistant transparent paper is 5 nm to 999 nm, the fibers are entangled with each other, and the cellulose is not grafted with hydrophobic groups, and the water-resistant transparent paper is not Contains additional hydrophobic additives.

Alternatively, the diameter of the cellulose fibers may be, for example, 30 nm, 60 nm, 90 nm, 120 nm, 150 nm, 180 nm, 210 nm, 240 nm, 270 nm, 300 nm, 330 nm, 360 nm, 390 nm, 420 nm, 450 nm, 480 nm, 510 nm, 540 nm, 570 nm, 600nm, 630nm, 650nm, 680nm, 710nm, 740nm, 770nm, 800nm, 830nm, 870nm, 900nm, 930nm, 960nm. Preferably, the diameter of the cellulose fibers is 250 nm to 850 nm, and further preferably, the diameter of the cellulose fibers is 400 nm to 750 nm. The diameter of cellulose fibers will affect the thickness of the final water-resistant paper to a certain extent, and, in the case of ungrafted hydrophobic groups, the diameter of cellulose fibers will directly affect the mutual entanglement force between fibers The strength and density will affect the wet tensile strength and transparency of the water-resistant transparent paper. Within the preset range, the wet tensile strength and transparency are optimally balanced, so that the two properties of the paper are more in line with the requirements.

The water-resistant transparent paper prepared by the invention does not modify the molecular structure of cellulose, and does not introduce refractory hydrophobic additives, so as to reduce the influence on the crystal structure of cellulose as much as possible, and maintain the performance of the cellulose-based material itself, thereby realizing The control of cellulose fibers with a diameter as low as 5nm makes the fibers intertwined and hooked up with each other through physical force, independent of the maintenance of hydrogen bonds, so they will not be attacked by water molecules, and still have high humidity in water. Strength, and will not cause too much impact on the transparency of the paper, the transparency can be as high as 92%, a good balance of water resistance and transparency of cellulose paper. In addition, after soaking, it has better abrasion resistance, burst resistance, tear resistance, folding resistance and softness than ordinary transparent paper. The water-resistant paper prepared by the invention is easy to degrade, is environmentally friendly, has superior performance and broad usage scenarios, and has good commercial prospects.

In a specific example, the thickness of the cellulose water-resistant transparent paper ranges from 5 μm to 250 μm. 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, 210μm, 220μm, 230μm, 240μm. Preferably, the thickness of the cellulose water-resistant transparent paper is 10 μm˜100 μm, and further preferably, the thickness of the cellulose water-resistant transparent paper is 15 μm˜25 μm. The thickness will affect the transparency and burst strength of the paper. Within the preset range, the cellulose water-resistant transparent paper can have a high burst strength under the premise of high transparency.

In a specific example, the cellulose is extracted from at least one of lianas, herbs, and woody plants.

The present invention also provides a method for preparing the aforementioned cellulose water-resistant transparent paper, which comprises the following steps: immersing the cellulose transparent paper in an alkaline solution for treatment, cleaning after the treatment is completed, and then drying.

The natural cellulose crystal form in nature is cellulose type I, and the molecular chains of cellulose type I are arranged in parallel. After the cellulose paper is immersed in an alkaline solution, it is converted into cellulose type II after being treated with an alkaline solution. The molecular chains of the cellulose type II are anti-parallel. From the appearance, the cellulose type II is helical. Specifically, when the cellulose paper is immersed in the lye solution, it first swells, so that the alkali penetrates into the crystal plane of the crystallization zone and forms a hydrated crystalline compound with the cellulose molecules. Part of it forms an amorphous structure; after cleaning and removing the lye, some areas form an anti-parallel chain structure to form cellulose type II; in the process of converting cellulose type I to cellulose type II, the fibers are twisted, and at the same time due to swelling, the fibers When the active space becomes larger, the fibers will be entangled to form a hooked structure, so that there is a strong physical interaction between the fibers. Water resistance of plain paper.

In one specific example, neutralization with acid may be performed prior to cleaning.

In a specific example, pressure maintenance may be performed after cleaning, the pressure maintaining pressure is 0.01 MPa to 20 MPa, and the pressure maintaining time is 0.1 h to 24 hours. Holding the water-resistant paper under pressure can make the paper smoother and easier to dry, which is convenient for subsequent processing.

In a specific example, the treatment in the lye solution is carried out in 2 to 5 times, that is, after a certain period of treatment, the solution is taken out, and then immersed in the lye solution for treatment, and the process is repeated; preferably, the treatment is repeated 3 times. Staged treatment can make the fiber shape twist and bend more fully, enhance the inter-fiber hooking effect, and make the cellulose paper have better water resistance without affecting the transparency.

In a specific example, the mass percentage concentration of the lye solution is 8% to 40%, and the temperature of the lye solution is greater than or equal to 8°C. Preferably, the mass percentage concentration of the lye solution is 15% to 30%, and the temperature of the lye solution is 15°C to 30°C. 25°C.

The temperature and concentration of the lye are directly related to the adjustment and control of the fiber shape. Unsuitable temperature and concentration will cause the fiber to swell too much, resulting in the less typical hooking between the fibers, and it cannot have sufficient strength. It is difficult to achieve water resistance; Within the preset range, the swelling and twisting of the fibers within the diameter range of the present invention reach an equilibrium state, which can greatly improve the water resistance and wet strength of the transparent water-resistant paper without causing a decrease in transparency.

In a specific example, the immersion treatment time in the lye solution is 10 seconds to 48 hours. Preferably, the treatment time in the alkali solution is 30 seconds to 24 hours, and further preferably, the treatment time in the alkali solution is 1 minute to 2 hours.

The treatment time of the lye is also related to the endowment of water resistance. Within the preset range, the reaction of cellulose can be carried out completely without affecting the transparency, burst strength, softness and other properties of the paper.

In a specific example, the alkaline solution is at least one of sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, calcium hydroxide solution, and ammonia water.

In a specific example, the sodium hydroxide solution is an aqueous sodium hydroxide solution with a concentration of 18% to 25% by mass.

In a specific example, the sodium hydroxide solution is a sodium hydroxide alcohol solution with a mass percentage concentration of 8% to 16%. In the sodium hydroxide alcohol solution, the mass ratio of water and alcohol is (0.5 to 1.2):1; preferably The sodium hydroxide solution is a sodium hydroxide alcohol solution with a mass percentage concentration of 12% to 16%, and in the sodium hydroxide alcohol solution, the mass ratio of water and alcohol is (0.8 to 1.2): 1; further preferably, hydrogen The sodium oxide solution is a sodium hydroxide alcohol solution with a mass percentage concentration of 14% to 16%. In the sodium hydroxide alcohol solution, the mass ratio of water and alcohol is 1:1.

In a specific example, the alcohol is isopropanol or ethanol, these two alcohols are almost harmless to the human body, and when combined in a certain mass ratio, can effectively reduce the hydration of sodium ions, so that the fibers within the diameter range of the present invention are relatively Better swelling and twisting can be achieved at low lye concentrations, higher water resistance can be achieved, the impact on paper transparency or other properties is minimized, and corrosion and loss of production equipment can be reduced.

The present invention also provides an electronic device comprising the aforementioned cellulose water-resistant transparent paper.

The present invention will be described in further detail below in conjunction with specific embodiments and comparative examples. It can be understood that the instruments and raw materials used in the following embodiments are more specific, and in other specific embodiments, they are not limited thereto.

The transparency of the following examples and comparative examples is measured according to the GB/T 2410-2008 national standard; the wet strength test steps in water are as follows: cut the cellulose water-resistant transparent paper material into a 10cm*1.5cm test strip, immerse it in water for 1 hour After taking it out, the wet tensile strength of the test strip was tested with a universal mechanical testing machine.

Example 1

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 20% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. In the water-resistant transparent paper, the fiber diameter is about 600 nm, the paper thickness is 20 μm, the transparency is 90%, and the strength of the paper in water is about 15.1 MPa.

Example 2

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 17% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 800 nm, the thickness of the paper is 20 μm, the transparency is 88%, and the strength of the paper in water is about 15.5 MPa.

Example 3

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 18% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 950 nm, the thickness of the paper is 20 μm, the transparency is 83%, and the strength of the paper in water is about 16 MPa.

Example 4

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 15% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. In the water-resistant transparent paper, the fiber diameter is about 300 nm, the paper thickness is 20 μm, the transparency is 92%, and the strength of the paper in water is about 13.8 MPa.

Example 5

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 10% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. In the water-resistant transparent paper, the fiber diameter is about 5 nm, the paper thickness is 20 μm, the transparency is 92%, and the strength of the paper in water is about 9.1 MPa.

Example 6

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 35% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter in the water-resistant transparent paper is about 900 nm, the thickness of the paper is 20 μm, the transparency is 78%, and the strength of the paper in water is about 14.8 MPa.

Example 7

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in a sodium hydroxide ethanol solution with a concentration of 15% by mass and a temperature of 25° C. (the mass ratio of ethanol and water was 1:1) for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 600 nm, the thickness of the paper is 20 μm, the transparency is 90%, and the strength of the paper in water is about 14.9 MPa.

Example 8

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in a sodium hydroxide ethanol solution with a concentration of 8% by mass and a temperature of 25° C. (the mass ratio of ethanol and water was 1:1) for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 350 nm, the thickness of the paper is 20 μm, the transparency is 92%, and the strength of the paper in water is about 13.2 MPa.

Example 9

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the reaction was carried out at a temperature of 50 ° C for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 20% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter in the water-resistant transparent paper is about 600 nm, the paper thickness is 50 μm, the transparency is 89%, and the strength of the paper in water is about 15.2 MPa.

Example 10

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the reaction was carried out for 10 minutes at a temperature of 50 ° C. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 20% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 600 nm, the thickness of the paper is 5 μm, the transparency is 92%, and the strength of the paper in water is about 14.5 MPa.

Example 11

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous potassium hydroxide solution with a concentration of 20% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 800 nm, the thickness of the paper is 20 μm, the transparency is 86%, and the strength of the paper in water is about 12.5 MPa.

Example 12

The cotton was digested with a mixed aqueous solution of 2.5mol/L sodium hydroxide and 0.4mol/L sodium sulfite for 8 hours, and then treated with 30% hydrogen peroxide at 100 °C for 3 hours to remove de-mass. After washing, TEMPO and NaBr were dissolved respectively. A solution was formed in a certain amount of distilled water, and the dosages of TEMPO and NaBr were 1.6% and 10% by mass of the absolute dry fiber pulp, respectively; then the TEMPO solution and NaBr solution were respectively mixed with the dispersed slurry and stirred for ten minutes. , 35 mL of sodium hypochlorite solution with a mass percentage concentration of 12.5% was added dropwise, and the pH value was controlled at 10.5. After 3 hours of reaction, 30 mL of slurry was taken and filtered with a suction filtration device to remove a large amount of water, and then the product was placed under pressure In the machine, under the pressure of 0.1MPa, the pressure is maintained for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an ammonia solution with a concentration of 20% by mass and a temperature of 25 ° C for 2 hours, then washed, and then the sample was placed in a press, and the pressure was 4MPa, and the pressure was maintained for 0.5 hours, and then The sample was dried to obtain a water-resistant transparent paper material. The fiber diameter in the water-resistant transparent paper is about 600 nm, the thickness of the paper is 150 μm, the transparency is 88%, and the strength of the paper in water is about 12.2 MPa.

Example 13

The bamboo is mixed with the sodium hypochlorite solution with a concentration of 15%, the mass ratio of bamboo and sodium hypochlorite is 1:6, and the reaction is carried out for 3 hours at room temperature. The filter device is suction filtered to remove a large amount of water, and then the product is placed in a press, and the pressure is kept at 2MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in a potassium hydroxide aqueous solution with a concentration of 40% by mass and a temperature of 12 ° C for 48 hours, then taken out, neutralized with an appropriate amount of acid, and washed with water three times to remove the residual chemicals; The steps were repeated three times, and then the sample was placed in a press, and maintained under a pressure of 2 MPa for 24 hours, and then the sample was dried to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 400 nm, the thickness of the paper is 250 μm, the transparency is 81%, and the strength of the paper in water is about 11.8 MPa.

Example 14

The grass was first cooked in 2.5mol/L sodium hydroxide and 0.03mol/L sodium sulfite solution for 10 hours, then in 30% sodium hydroxide solution for 3 hours to remove lignin, and fully stirred by a mixer to obtain microfibrillated fibers 4mL, and suction filtration with a suction filtration device to remove a large amount of water, neutralize with 0.1mol/L hydrochloric acid, and dry to obtain transparent paper;

Put the transparent paper in a sodium hydroxide aqueous solution with a concentration of 25% by mass and a temperature of 18 ° C for 10 seconds, take it out, neutralize it with an appropriate amount of acid, and wash the sample with water three times to remove the residual chemicals; The steps were repeated three times, and then the sample was placed in a press, and maintained at a pressure of 4 MPa for 0.5 hours, and then the sample was dried to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 40 nm, the thickness of the paper is 15 μm, the transparency is 83%, and the strength of the paper in water is about 12.5 MPa.

Comparative Example 1

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 7% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 500 nm, the thickness of the paper is 20 μm, the transparency is 90%, and the strength of the paper in water is about 0.5 MPa.

Comparative Example 2

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in a sodium hydroxide ethanol solution with a concentration of 5% by mass and a temperature of 25° C. (the mass ratio of ethanol and water was 1:1) for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 450 nm, the thickness of the paper is 20 μm, the transparency is 90%, and the strength of the paper in water is about 0.1 MPa.

Comparative Example 3

The basswood sawdust was mixed with a sodium hypochlorite solution with a concentration of 15%, the mass ratio of sawdust and sodium hypochlorite was 1:10, and the temperature was 50 ° C, and the reaction was carried out for 10 minutes. After the reaction, washed with water three times to remove the residual sodium hypochlorite. The slurry was filtered with a suction filtration device to remove a large amount of water, and then the product was placed in a press, and the pressure was maintained at 0.1 MPa for 0.1 hour to obtain transparent paper;

The transparent paper was placed in an aqueous sodium hydroxide solution with a concentration of 10% by mass and a temperature of 25° C. for 5 minutes, and then washed for 5 minutes to obtain a water-resistant transparent paper material. The fiber diameter of the water-resistant transparent paper is about 1 nm, the thickness of the paper is 20 μm, the transparency is 95%, and the strength of the paper in water is about 2.3 MPa.

The transparent paper prepared in each embodiment of the present invention not only achieves water resistance after water resistance treatment, but also has no negative impact on transparency, and has good wet strength, which makes the water-resistant transparent paper have the possibility to replace plastic films.

In Comparative Examples 1 and 2, the lye concentration was too low, the fibers could not be swelled and twisted well, so they could not be intertwined with each other, and water resistance could not be obtained; Alkaline treatment also cannot well balance the strength, transparency, water resistance and other properties of the fiber itself, and the wet strength of the treated paper is too low to be used.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are more specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims (9)

1. The preparation method of the cellulose waterproof transparent paper is characterized by comprising the following steps: immersing the cellulose transparent paper into alkali liquor for treatment, cleaning after the treatment is finished, and then drying;

wherein the mass percentage concentration of the alkali liquor is 15-30%, the temperature of the alkali liquor is 15-30 ℃, and the time for immersing the alkali liquor in the alkali liquor is 10 seconds-48 hours; the cellulose water-resistant transparent paper is characterized in that the diameter of cellulose fibers in the cellulose water-resistant transparent paper is 5-999 nm, the cellulose fibers are mutually entangled, hydrophobic groups are not grafted on the cellulose, and the cellulose water-resistant transparent paper does not contain additional hydrophobic additives.

2. The method according to claim 1, wherein the cellulose in the cellulose transparency is extracted from at least one of vines, herbaceous plants, woody plants.

3. The preparation method of claim 1, wherein the mass percentage concentration of the alkali liquor is 18-20%, and the temperature of the alkali liquor is 18-25 ℃.

4. The method according to claim 1, wherein the alkali solution is at least one of a sodium hydroxide solution, a potassium hydroxide solution, a lithium hydroxide solution, a calcium hydroxide solution, and ammonia.

5. The preparation method of claim 4, wherein the sodium hydroxide solution is 18-25% by mass.

6. The preparation method of the water-soluble sodium hydroxide solution, which is characterized in that the sodium hydroxide solution is 8-16% by mass of an alcoholic sodium hydroxide solution, and the mass ratio of water to alcohol in the alcoholic sodium hydroxide solution is (0.5-1.2): 1.

7. A water-resistant cellulose transparent paper, which is characterized by being prepared by the preparation method of any one of claims 1 to 6.

8. The cellulose water-resistant transparent paper as claimed in claim 7, wherein the thickness of the cellulose water-resistant transparent paper is 5 μm to 250 μm.

9. An electronic device comprising the cellulose water-resistant transparent paper according to any one of claims 7 to 8.

Images