A method for preparing high water absorption and low air permeability environment-friendly decorative base paper by using bamboo pulp fibers

Abstract

The application belongs to the technical field of papermaking, and particularly relates to a method for preparing environment-friendly decorative base paper with high water absorption and low air permeability by using bamboo pulp fibers, which comprises the following steps: S1, preparing wet pulp; S2, mixing pulp; S3, preparing base paper; S4, preparing coating; and S5, paper surface coating treatment. The decorative base paper prepared by the method for preparing environment-friendly decorative base paper with high water absorption and low air permeability by using bamboo pulp fibers has the advantages of low filler content, high physical strength, good water absorption and low air permeability.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, and in particular relates to a method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber. Background Technology

[0002] Decorative base paper is made from high-quality wood pulp and titanium dioxide through a wet papermaking process, and then processed through printing, resin impregnation, high-pressure lamination, and other processes. It is used as a surface decoration material for the bottom layer, surface layer, and protective layer of artificial boards.

[0003] Besides its aesthetic and decorative function, decorative base paper is primarily used to cover the particleboard underneath, preventing the substrate from showing through. Therefore, it typically requires the addition of a large amount of titanium dioxide, a filler with high refractive index and good opacity. However, this large amount of filler remains between the wood pulp fibers, increasing the gaps between them. This affects the fibers' ability to come together, hindering hydrogen bond formation and thus reducing the inter-fiber bonding strength, ultimately leading to a decrease in the physical strength of the decorative base paper. Furthermore, since decorative base paper is an impregnated paper, it needs to be processed in an impregnation machine with amino resins, such as melamine-formaldehyde resin and phenolic resin, to rapidly absorb several times its own weight in resin. Currently, the speed of domestic horizontal sizing machines is 30-40 m / min. Therefore, the paper's sizing time in the sizing tank is only a few seconds. To achieve the specified sizing amount and uniform absorption within this short time, the paper to be sizing must have good and stable water or liquid absorption properties. Otherwise, it will affect the sizing speed and output, and in severe cases, quality problems such as dried flowers, white spots, hazy defects, pitting on the board surface, and blurred patterns will occur after pressing. Therefore, the water absorption performance of decorative base paper is an important indicator that should be strictly controlled during the production process. However, the addition of a large amount of filler can significantly affect the water absorption performance of the paper. When the filler content is too high, the paper's water absorption capacity will decrease significantly.

[0004] Furthermore, low air permeability reduces the penetration of ink or paint into the paper, preventing blurring and smudging of printed patterns and maintaining the clarity of printed details. Simultaneously, low air permeability reduces the entry of outside air and moisture into the packaging, effectively protecting the quality and lifespan of the internal materials. Therefore, decorative base paper must also possess low air permeability. However, the addition of large amounts of fillers increases the air permeability of the paper, affecting subsequent printing quality and the product's lifespan. At the same time, highly permeable decorative base paper absorbs excessive melamine resin during impregnation, resulting in higher methanol release during use and impacting its environmental friendliness.

[0005] In addition, the addition of a large amount of expensive titanium dioxide filler will result in a lot of loss due to the low retention rate during wet papermaking, which will significantly increase the production cost. However, if retention aids are added, flocculation is likely to occur, affecting the uniformity of the decorative base paper and thus bringing about a series of quality problems.

[0006] In view of this, providing a decorative base paper with low filler content, high physical strength, good water absorption and low air permeability is one of the technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned technical problems by providing a method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber.

[0008] In view of this, the present invention provides a method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber, comprising the following steps:

[0009] S1, Preparation of wet pulp: Weigh 200-400 parts by weight of oven-dry softwood pulp board and 150-250 parts by weight of oven-dry hardwood pulp board, respectively, and mix and soak them in an appropriate amount of warm water; then pour the soaked mixed pulp into a pulper, add water and pulp, the pulping degree of the mixed pulp is 27-50°SR; after pulping, filter, wring dry, then place in a plastic bag, seal and let stand to balance the moisture, and the wet pulp is obtained after standing.

[0010] S2, Pulp Preparation: Weigh a certain amount of the wet pulp obtained in step S1, add water, and place it in a descaling machine for descaling; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to make it evenly mixed; wherein, the amount of bamboo pulp nanocellulose added is 0.5-2% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 0.5-2% of the total amount of oven-dried pulp board in step S1;

[0011] S3, Preparation of base paper: Add 3 to 5 times the total volume of oven-dry pulp board water to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add 8 to 15 times the total volume of oven-dry pulp board water for a second dilution, then introduce compressed air and stir for 3 to 6 minutes, then form wet paper, and after pressing and drying the wet paper sheet, obtain the carrier base paper for use;

[0012] S4, Preparation of coating: A certain amount of bamboo pulp microfibrillated cellulose is added to water and stirred evenly to prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 0.5-5%; then it is placed in an ultrasonic device for ultrasonic dispersion once. After the first ultrasonic dispersion, a certain amount of PVA particles and titanium dioxide particles are added to the solution; then the mixture is heated and fully swollen, and then placed in an ultrasonic device for a second ultrasonic dispersion; after the second ultrasonic dispersion, the mixture is heated to 90-95℃ and stirred until the PVA particles are completely dissolved; then the mixture is placed in an ultrasonic device for a third ultrasonic dispersion. After the third ultrasonic dispersion, it is allowed to stand to degas, and the coating is obtained.

[0013] S5, Paper surface coating treatment: The coating prepared in step S4 is applied to the surface of the carrier paper prepared in step S3 by a rod coating method. The coated paper is first dried in an oven at 40-60℃ for 15-30 minutes, and then placed in a constant temperature and humidity test chamber for 20-30 hours to obtain highly absorbent, low-permeability, environmentally friendly decorative base paper.

[0014] Furthermore, in step S1, the weight ratio of the softwood pulp oven-dried board to the hardwood pulp oven-dried board is 3:2.

[0015] Furthermore, in step S1, the temperature of the soaking water is 30–50°C, and the soaking time is 2–5 hours.

[0016] Furthermore, in step S1, the beating degree of the mixed slurry is 30°SR.

[0017] Furthermore, in step S1, after pulping is completed, the pulp is filtered and wrung out until the moisture content is 60-90%, then placed in a plastic bag, sealed, and left to stand at room temperature for 3-5 hours to balance the moisture.

[0018] Furthermore, in step S2, the amount of bamboo pulp nanocellulose added is 1% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 1% of the total amount of oven-dried pulp board in step S1.

[0019] Furthermore, in step S4, the parameters for the first ultrasonic dispersion are: dispersion at 80-100 Hz for 10-20 min; the parameters for the second ultrasonic dispersion are: dispersion at 90-120 Hz for 10-20 min; and the parameters for the third ultrasonic dispersion are: dispersion at 100-150 Hz for 10-20 min.

[0020] Furthermore, in step S4, the amount of PVA particles added is 1 to 3 times the weight of bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added is 3 to 8 times the weight of bamboo pulp microfibrillated cellulose in the coating.

[0021] Furthermore, in step S5, the relative humidity of the constant temperature and humidity test chamber is 40-60% and the temperature is 20-30℃.

[0022] The decorative base paper is prepared according to the above method.

[0023] The decorative base paper prepared according to the method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber as described in this invention has the advantages of low filler content, high physical strength, good water absorption and low permeability. Attached Figure Description

[0024] Figure 1 The results are the contact angle test results of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose added in Experiment Example 2;

[0025] Figure 2 The results are the air permeability test results of decorative base paper under different bamboo pulp microfibrillated cellulose addition amounts in Experiment Example 3;

[0026] Figure 3 The results are the test results of the wet strength of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose added in Experiment Example 4;

[0027] Figure 4 The results show the folding endurance of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose added in Experiment Example 5.

[0028] Figure 5 The results are the tear strength test results of decorative base paper under different bamboo pulp microfibrillated cellulose addition amounts in Experiment Example 6. Detailed Implementation

[0029] The technical solutions in the embodiments of this application will be clearly described below with reference to specific examples. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0030] It should be noted that, in this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0031] Bamboo pulp microfibrillated cellulose:

[0032] Bamboo pulp microfibrillated cellulose is a highly swollen colloidal cellulose product obtained through microfibrillation treatment. It features high strength, good water absorption, and a large specific surface area. Microfibrillation is a processing technique that refines cellulose particles through mechanical or chemical methods, resulting in smaller particle size and finer fibers. Bamboo pulp microfibrillated cellulose is a cellulose product produced by microfibrillating bamboo pulp. Due to its flexible texture and extremely strong hydrogen bonding ability, bamboo pulp microfibrillated cellulose exhibits excellent reinforcing effects in paper, plastic adhesives, and composite materials. In the papermaking industry, bamboo pulp microfibrillated cellulose is generally used as an additive within the pulp, which enhances the overall performance of the paper to a certain extent. Furthermore, bamboo pulp microfibrillated cellulose also has significant applications in the coatings industry. Its high viscosity and excellent bonding properties allow it to be used as an auxiliary adhesive in coatings, reducing the total amount of adhesive used and increasing the solids content of the coating.

[0033] Bamboo pulp nanocellulose:

[0034] Bamboo pulp nanocellulose is a cellulose product extracted from bamboo pulp and processed at the nanoscale to reduce its particle or fiber size to the nanometer level. The diameter of bamboo pulp nanocellulose is generally between a few nanometers and tens of nanometers, and the length is usually between hundreds of nanometers and several micrometers.

[0035] Because bamboo pulp nanocellulose has very small particle or fiber sizes, typically at the nanoscale, it possesses a larger surface area and more surface active sites, which is beneficial for its applications in adsorption, catalysis, and reinforcing materials. Furthermore, bamboo pulp nanocellulose exhibits excellent mechanical properties, such as high strength and high modulus, making it suitable for use in reinforcing materials and nanocomposite materials to improve material performance.

[0036] Environmentally friendly decorative base paper with high water absorption and low air permeability is prepared using bamboo pulp fiber:

[0037] A method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber includes the following steps:

[0038] S1, Preparation of wet pulp: Weigh 200-400 parts by weight of oven-dry softwood pulp board and 150-250 parts by weight of oven-dry hardwood pulp board, respectively, and mix and soak them in an appropriate amount of warm water; then pour the soaked mixed pulp into a pulper, add water and pulp, the pulping degree of the mixed pulp is 27-50°SR; after pulping, filter, wring dry, then place in a plastic bag, seal and let stand to balance the moisture, and the wet pulp is obtained after standing.

[0039] S2, Pulp Preparation: Weigh a certain amount of the wet pulp obtained in step S1, add water, and place it in a descaling machine for descaling; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to make it evenly mixed; wherein, the amount of bamboo pulp nanocellulose added is 0.5-2% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 0.5-2% of the total amount of oven-dried pulp board in step S1;

[0040] S3, Preparation of base paper: Add 3 to 5 times the total volume of oven-dry pulp board water to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add 8 to 15 times the total volume of oven-dry pulp board water for a second dilution, then introduce compressed air and stir for 3 to 6 minutes, then form wet paper, and after pressing and drying the wet paper sheet, obtain the carrier base paper for use;

[0041] S4, Preparation of coating: A certain amount of bamboo pulp microfibrillated cellulose is added to water and stirred evenly to prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 0.5-5%; then it is placed in an ultrasonic device for ultrasonic dispersion once. After the first ultrasonic dispersion, a certain amount of PVA particles and titanium dioxide particles are added to the solution; then the mixture is heated and fully swollen, and then placed in an ultrasonic device for a second ultrasonic dispersion; after the second ultrasonic dispersion, the mixture is heated to 90-95℃ and stirred until the PVA particles are completely dissolved; then the mixture is placed in an ultrasonic device for a third ultrasonic dispersion. After the third ultrasonic dispersion, it is allowed to stand to degas, and the coating is obtained.

[0042] S5, Paper surface coating treatment: The coating prepared in step S4 is applied to the surface of the carrier paper prepared in step S3 by a rod coating method. The coated paper is first dried in an oven at 40-60℃ for 15-30 minutes, and then placed in a constant temperature and humidity test chamber for 20-30 hours to obtain highly absorbent, low-permeability, environmentally friendly decorative base paper.

[0043] Preferably, in step S1, the weight ratio of softwood pulp oven-dried board to hardwood pulp oven-dried board is 3:2.

[0044] Preferably, in step S1, the weight ratio of the total amount of oven-dried softwood pulp and hardwood pulp to the soaking water is 1:(8-15).

[0045] Preferably, in step S1, the temperature of the soaking water is 30-50°C and the soaking time is 2-5 hours; more preferably, the temperature of the soaking water is 40°C and the soaking time is 3 hours.

[0046] As some examples of the present invention, in step S1, the soaked slurry can be poured into a trough pulper for mechanical pulping.

[0047] Preferably, in step S1, the amount of water added to the pulper is 30 to 80 times the total weight of the oven-dry pulp board of softwood pulp and hardwood pulp.

[0048] Preferably, in step S1, the beating degree of the mixed slurry is 30°SR.

[0049] Preferably, in step S1, after pulping, the pulp is filtered and wrung out until the moisture content is 60-90%, then placed in a plastic bag, sealed, and left to stand at room temperature for 3-5 hours to balance the moisture.

[0050] Preferably, in step S2, a certain amount of wet slurry is weighed, and water of 1.5 to 2.5 times the weight of the wet slurry is added to it before it is placed in a dewatering machine for dewatering.

[0051] Preferably, in step S2, the amount of bamboo pulp nanocellulose added is 1% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 1% of the total amount of oven-dried pulp board in step S1.

[0052] Preferably, in step S3, the total amount of compressed air introduced per unit volume, i.e. per liter of slurry, is 0.5 to 1 m³. 3 .

[0053] As some examples of the present invention, in step S3, after compressed air is introduced and stirred for a set time, the drain wrench can be opened to form wet paper; then, after pressing the wet paper sheet with an absorbent cloth, it is placed in a flat dryer to dry.

[0054] Preferably, in step S4, the parameters for the first ultrasonic dispersion are: dispersion at 80-100 Hz for 10-20 min; the parameters for the second ultrasonic dispersion are: dispersion at 90-120 Hz for 10-20 min; and the parameters for the third ultrasonic dispersion are: dispersion at 100-150 Hz for 10-20 min.

[0055] Preferably, in step S4, the amount of PVA particles added is 1 to 3 times the weight of bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added is 3 to 8 times the weight of bamboo pulp microfibrillated cellulose in the coating, wherein the titanium dioxide particles are nanoparticles.

[0056] Preferably, in step S4, after adding PVA particles and titanium dioxide particles, the mixture is heated to 50-70°C and swelled under stirring for 20-60 minutes.

[0057] As some examples of the present invention, in step S5, the specific process of the surface coating treatment is as follows: an appropriate amount of coating is added at the beginning of the roller, and the roller is pressed back and forth 5 times in one direction on one side to make the coating evenly coated on the surface of the base paper.

[0058] Preferably, in step S5, the coating amount is 10-18 g / m². 2 .

[0059] Preferably, in step S5, the relative humidity of the constant temperature and humidity test chamber is 40-60% and the temperature is 20-30℃.

[0060] The following specific examples illustrate the method for preparing highly absorbent, low-permeability, environmentally friendly decorative base paper using bamboo pulp fiber according to the present invention:

[0061] Example 1

[0062] A method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber includes the following steps:

[0063] S1, Preparation of wet pulp: Weigh 250g of oven-dry softwood pulp board and 250g of oven-dry hardwood pulp board, respectively, and mix and soak them in 4 liters of 50℃ warm water for 2 hours; then pour the soaked mixed pulp into a pulper, add 15L of water for pulping, and the pulping degree of the mixed pulp is 50°SR; after pulping, filter and wring dry until the pulp moisture content is 90%, then place it in a plastic bag, seal it, and let it stand at room temperature for 5 hours to balance the moisture, and the wet pulp is obtained after standing.

[0064] S2, Pulp Preparation: Weigh 500g of the wet pulp obtained in step S1, add 0.8L of water, and place it in a delamination machine for delamination; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to make it evenly mixed; wherein, the amount of bamboo pulp nanocellulose added is 0.5% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 2% of the total amount of oven-dried pulp board in step S1;

[0065] S3, Preparation of base paper: Add water three times the total volume of oven-dry pulp to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add water 15 times the total volume of oven-dry pulp for a second dilution, then pass compressed air through and stir for 6 minutes, then form wet paper, and after pressing and drying the wet paper sheets, obtain the carrier base paper for later use;

[0066] S4, Preparation of the coating: Add 5g of bamboo pulp microfibrillated cellulose to 1000ml of water, stir evenly to prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 0.5%; then place it in an ultrasonic device for ultrasonic dispersion once. After the first ultrasonic dispersion, add a certain amount of PVA particles and titanium dioxide particles to the solution; then heat the mixture and allow it to fully swell, and place it in an ultrasonic device again for a second ultrasonic dispersion; after the second ultrasonic dispersion, heat the mixture to 90℃ and stir until the PVA particles are completely dissolved; then place the mixture in an ultrasonic device for a third ultrasonic dispersion. After the third ultrasonic dispersion, allow it to stand to remove bubbles to obtain the coating; the parameters for the first ultrasonic dispersion are: dispersion at 80Hz for 20min; the parameters for the second ultrasonic dispersion are: dispersion at 90Hz for 20min; the parameters for the third ultrasonic dispersion are: dispersion at 150Hz for 20min; the amount of PVA particles added is 1 times the weight of bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added is 3 times the weight of bamboo pulp microfibrillated cellulose in the coating.

[0067] S5, Paper surface coating treatment: The coating obtained in step S4 is applied to the surface of the carrier paper prepared in step S3 using a rod coating method. The coating amount is 18 g / m². 2The coated paper is first dried in an oven at 60℃ for 15 minutes, and then placed in a constant temperature and humidity test chamber with a relative humidity of 60% and a temperature of 25℃ for 30 hours to obtain highly absorbent, low-permeability, environmentally friendly decorative base paper.

[0068] Example 2

[0069] A method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber includes the following steps:

[0070] S1, Preparation of wet pulp: Weigh 350g of oven-dry softwood pulp board and 150g of oven-dry hardwood pulp board, respectively, and mix and soak them in 7.5L of 30℃ warm water for 5 hours; then pour the soaked mixed pulp into a pulper, add 40L of water for pulping, and the pulping degree of the mixed pulp is 27°SR; after pulping, filter and wring dry until the pulp moisture content is 60%, then place it in a plastic bag, seal it, and let it stand at room temperature for 3 hours to balance the moisture. After standing, wet pulp is obtained.

[0071] S2, Pulp Preparation: Weigh 500g of the wet pulp obtained in step S1, add 1.25L of water, and place it in a delamination machine for delamination; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to make it evenly mixed; wherein, the amount of bamboo pulp nanocellulose added is 2% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 0.5% of the total amount of oven-dried pulp board in step S1;

[0072] S3, Preparation of base paper: Add 5 times the amount of water to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add 8 times the amount of water to the mixed pulp for a second dilution, then pass compressed air through and stir for 3 minutes, then form wet paper, and after pressing and drying the wet paper sheet, obtain the carrier base paper for later use;

[0073] S4, Preparation of the coating: 7.5g of bamboo pulp microfibrillated cellulose was added to 500ml of water and stirred evenly to prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 1.5%. The suspension was then subjected to ultrasonic dispersion once. After the first ultrasonic dispersion, a certain amount of PVA particles and titanium dioxide particles were added to the solution. The mixture was then heated and allowed to fully swell before being subjected to a second ultrasonic dispersion. After the second ultrasonic dispersion, the mixture was heated to 95℃ and stirred until the PVA particles were completely dissolved. The mixture was then subjected to ultrasonic dispersion three times. After the three ultrasonic dispersions, the mixture was allowed to stand to remove bubbles, yielding the coating. The parameters for the first ultrasonic dispersion were: 100Hz for 10min; the parameters for the second ultrasonic dispersion were: 120Hz for 10min; and the parameters for the third ultrasonic dispersion were: 100Hz for 10min. The amount of PVA particles added was 3 times the weight of the bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added was 8 times the weight of the bamboo pulp microfibrillated cellulose in the coating.

[0074] S5, Paper surface coating treatment: The coating obtained in step S4 is applied to the surface of the carrier paper prepared in step S3 using a rod coating method. The coating amount is 10 g / m². 2 The coated paper is first dried in an oven at 40℃ for 30 minutes, and then placed in a constant temperature and humidity test chamber with a relative humidity of 40% and a temperature of 30℃ for 20 hours to obtain highly absorbent, low-permeability, environmentally friendly decorative base paper.

[0075] Example 3

[0076] A method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber includes the following steps:

[0077] S1, Preparation of wet pulp: Weigh 300g of oven-dry softwood pulp board and 200g of oven-dry hardwood pulp board, respectively, and mix and soak them in 6 liters of 40℃ warm water for 3 hours; then pour the soaked mixed pulp into a pulper, add 25L of water for pulping, and the pulping degree of the mixed pulp is 30°SR; after pulping, filter and wring dry until the pulp moisture content is 70%, then place it in a plastic bag, seal it, and let it stand at room temperature for 4 hours to balance the moisture, and the wet pulp is obtained after standing.

[0078] S2, Pulp preparation: Weigh 500g of the wet pulp obtained in step S1, add 1L of water, and place it in a delamination machine for delamination; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to make it evenly mixed; wherein, the amount of bamboo pulp nanocellulose added is 1% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 1% of the total amount of oven-dried pulp board in step S1.

[0079] S3, Preparation of base paper: Add 4 times the amount of water to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add 10 times the amount of water to the mixed pulp for a second dilution, then pass compressed air through and stir for 5 minutes, then form wet paper, and after pressing and drying the wet paper sheet, obtain the carrier base paper for later use;

[0080] S4, Preparation of the coating: Add 1g of bamboo pulp microfibrillated cellulose to 100ml of water, stir evenly to prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 1%; then place it in an ultrasonic device for ultrasonic dispersion once. After the first ultrasonic dispersion, add a certain amount of PVA particles and titanium dioxide particles to the solution; then heat the mixture and allow it to fully swell, and place it in an ultrasonic device again for a second ultrasonic dispersion; after the second ultrasonic dispersion, heat the mixture to 93℃ and stir until the PVA particles are completely dissolved; then place the mixture in an ultrasonic device for a third ultrasonic dispersion. After the third ultrasonic dispersion, allow it to stand to remove bubbles to obtain the coating; the parameters for the first ultrasonic dispersion are: dispersion at 90Hz for 15min; the parameters for the second ultrasonic dispersion are: dispersion at 100Hz for 15min; the parameters for the third ultrasonic dispersion are: dispersion at 120Hz for 15min; the amount of PVA particles added is twice the weight of bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added is five times the weight of bamboo pulp microfibrillated cellulose in the coating.

[0081] S5, Paper surface coating treatment: The coating obtained in step S4 is applied to the surface of the carrier paper prepared in step S3 using a rod coating method. The coating amount is 15 g / m². 2 The coated paper is first dried in an oven at 50°C for 20 minutes, and then placed in a constant temperature and humidity test chamber at 50% relative humidity and 20°C for 25 hours to obtain highly absorbent, low-permeability, environmentally friendly decorative base paper.

[0082] Experimental Example 1

[0083] The following single-factor experiments were conducted to study the changes in water absorption rate of decorative base paper under different beating degrees and the changes in water absorption rate of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0084] Following the operation process shown in Example 3 above, high water absorption and low air permeability environmentally friendly decorative base paper was prepared by using beating degrees of 15°SR, 30°SR, and 45°SR respectively when the bamboo pulp microfibrillated cellulose addition amount was 0, 1%, 2%, 3%, and 4% (i.e., the concentration of bamboo pulp microfibrillated cellulose suspension was 0, 1%, 2%, 3%, and 4%). The water absorption rate of the obtained decorative base paper was tested, and the test results are shown in Table 1 below.

[0085] Table 1. Water Absorption Rate of Decorative Base Paper

[0086] beating degree No additions Add 1% Add 2% Add 3% Add 4% 15°SR 3.5 4.1 4.5 4.7 4.9 30°SR 3.5 4.2 4.6 4.9 5.2 45°SR 3.5 4.2 5.0 5.4 5.6

[0087] As shown in Table 1, compared with the blank sample without added bamboo pulp microfibrillated cellulose, the addition of bamboo pulp microfibrillated cellulose increased the water absorption rate and improved the water absorption of the paper. Furthermore, the water absorption performance gradually improved with increasing amounts of bamboo pulp microfibrillated cellulose. This is mainly because, compared to the blank sample, the addition of bamboo pulp microfibrillated cellulose, after combining with the original pulp fibers, increases the number of water absorption sites in the paper, thus raising the water absorption rate.

[0088] In addition, the gradual increase in beating degree also helps to increase the water absorption rate of the decorative base paper.

[0089] Experimental Example 2

[0090] The following single-factor experiments were conducted to study the changes in the contact angle of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0091] Following the operation process shown in Example 3 above, bamboo pulp microfibrillated cellulose suspensions were prepared by adding 0g, 1g, 2g, 3g, and 4g of bamboo pulp microfibrillated cellulose in 100ml of water. Then, highly absorbent, low-permeability, environmentally friendly decorative base paper was prepared by coating and processing according to the method described in Example 3. The contact angle of the obtained decorative base paper was then measured to obtain the following results: Figure 1 The test results are shown.

[0092] Depend on Figure 1 It can be seen that when the amount of bamboo pulp microfibrillated cellulose added is 0g, the contact angle of the resulting decorative base paper is 89.6°. As the amount of bamboo pulp microfibrillated cellulose added increases, the contact angle of the decorative base paper continuously decreases. When the amount of bamboo pulp microfibrillated cellulose added is 1g, the contact angle decreases to 83.4°. With further increases in the amount of bamboo pulp microfibrillated cellulose added to 2g, 3g, and 4g, the contact angles of the decorative base paper are 78.9°, 76.8°, and 74.3°, respectively. Therefore, the effect of bamboo pulp microfibrillated cellulose on the contact angle of the decorative base paper is that the contact angle continuously decreases as the amount of nanofiber increases.

[0093] The above results indicate that the addition of bamboo pulp microfibrillated cellulose has a negative effect on the hydrophobicity of decorative base paper, but increases its water absorption.

[0094] Experimental Example 3

[0095] The following single-factor experiments were conducted to study the changes in air permeability of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0096] Following the operation process shown in Example 3 above, bamboo pulp microfibrillated cellulose suspensions were prepared by adding 0g, 1g, 2g, 3g, and 4g of bamboo pulp microfibrillated cellulose and 100ml of water, respectively. These suspensions were then coated and used to prepare highly absorbent, low-permeability, environmentally friendly decorative base paper. The air permeability of the resulting decorative base paper was then tested, and the results were as follows: Figure 2 The test results are shown.

[0097] Depend on Figure 2 It can be seen that when the amount of bamboo pulp microfibrillated cellulose added is 0g, the air permeability of the decorative base paper is 221.488L / (s·㎡); as the amount of bamboo pulp microfibrillated cellulose added increases, the air permeability of the decorative base paper decreases significantly. When the amount of bamboo pulp microfibrillated cellulose added is 1g, the air permeability of the decorative base paper is 51.816L / (s·㎡); as the amount of bamboo pulp microfibrillated cellulose added further increases, the downward trend of the air permeability of the decorative base paper tends to level off. When the amount of bamboo pulp microfibrillated cellulose added reaches 4g, the air permeability of the decorative base paper decreases to 38.1L / (s·㎡).

[0098] Therefore, it can be seen that the effect of bamboo pulp microfibrillated cellulose on the air permeability of decorative base paper is that the air permeability of decorative base paper decreases as the amount of bamboo pulp microfibrillated cellulose added increases; and there is a significant difference compared with the blank group without bamboo pulp microfibrillated cellulose added. This indicates that in this invention, the addition of bamboo pulp microfibrillated cellulose has a reducing effect on the air permeability of paper.

[0099] Test Example 4

[0100] The following single-factor experiments were conducted to study the changes in wet strength of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0101] Following the operation process shown in Example 3 above, bamboo pulp microfibrillated cellulose suspensions were prepared by adding 0g, 1g, 2g, 3g, and 4g of bamboo pulp microfibrillated cellulose and 100ml of water, respectively. These suspensions were then coated and used to prepare highly absorbent, low-permeability, environmentally friendly decorative base paper. The wet strength, i.e., tensile stress, of the obtained decorative base paper was then tested to obtain the following results: Figure 3 The test results are shown.

[0102] Depend on Figure 3It can be seen that when the amount of bamboo pulp microfibrillated cellulose added is 0, the tensile strength of the decorative base paper is the lowest, at 45.97 MPa. As the amount of bamboo pulp microfibrillated cellulose added increases, the tensile strength of the decorative base paper also increases. For example, the tensile strength of paper with 3g of bamboo pulp microfibrillated cellulose added is more than 45% higher than that with 0g. Therefore, it can be inferred that the addition of bamboo pulp microfibrillated cellulose is beneficial to improving the tensile strength of decorative base paper.

[0103] Experimental Example 5

[0104] The following single-factor experiments were conducted to study the changes in folding endurance of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0105] Following the operation process shown in Example 3 above, bamboo pulp microfibrillated cellulose suspensions were prepared by adding 0g, 1g, 2g, 3g, and 4g of bamboo pulp microfibrillated cellulose and 100ml of water, respectively. These suspensions were then coated and used to prepare highly absorbent, low-permeability, environmentally friendly decorative base paper. The folding endurance of the obtained decorative base paper was then tested, and the results were as follows: Figure 4 The test results are shown.

[0106] Depend on Figure 4 It can be seen that the folding endurance of the decorative base paper first decreases and then increases with the increase of the amount of bamboo pulp microfibrillated cellulose added. When the amount of bamboo pulp microfibrillated cellulose added is 0g, the folding endurance of the decorative base paper is 3.18. When the amount of bamboo pulp microfibrillated cellulose added is 1g, the folding endurance of the decorative base paper decreases to a minimum of 3.12. Subsequently, when the amount of bamboo pulp microfibrillated cellulose added is 2g, the folding endurance of the decorative base paper increases to 3.21. Therefore, it can be concluded that only when the amount of bamboo pulp microfibrillated cellulose added is within a reasonable range can the folding endurance of the decorative base paper reach a high level.

[0107] Experimental Example 6

[0108] The following single-factor experiments were conducted to study the changes in tear strength of decorative base paper under different amounts of bamboo pulp microfibrillated cellulose. Specifically:

[0109] Following the operation process shown in Example 3 above, bamboo pulp microfibrillated cellulose suspensions were prepared by adding 0g, 1g, 2g, 3g, and 4g of bamboo pulp microfibrillated cellulose and 100ml of water, respectively. These suspensions were then coated and used to prepare highly absorbent, low-permeability, environmentally friendly decorative base paper. The tear resistance of the resulting decorative base paper was then tested, and the results were as follows: Figure 5 The test results are shown.

[0110] Depend on Figure 5It can be seen that the tear strength and folding endurance of decorative base paper show a consistent trend, first decreasing and then increasing with the increase of bamboo pulp microfibrillated cellulose. Appropriate addition of bamboo pulp microfibrillated cellulose can significantly improve various mechanical properties of the paper.

[0111] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber, characterized in that, Including the following steps: S1, Preparation of wet pulp: Weigh 200-400 parts by weight of oven-dry softwood pulp board and 150-250 parts by weight of oven-dry hardwood pulp board, respectively, and mix and soak them in an appropriate amount of warm water; then pour the soaked mixed pulp into a pulper, add water and pulp, the pulping degree of the mixed pulp is 27-50°SR; after pulping, filter, wring dry, then place in a plastic bag, seal and let stand to balance the moisture, and the wet pulp is obtained after standing. S2, Pulp Preparation: Weigh a certain amount of the wet pulp obtained in step S1, add water, and place it in a descaling machine for descaling; then, add bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose to the pulp and stir thoroughly to ensure uniform mixing; wherein, the amount of bamboo pulp nanocellulose added is 0.5~2% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 0.5~2% of the total amount of oven-dried pulp board in step S1; S3, Preparation of base paper: Add 3 to 5 times the total volume of oven-dry pulp board water to the mixed pulp of defragmented softwood pulp, hardwood pulp, bamboo pulp nanocellulose and bamboo pulp microfibrillated cellulose for a first dilution; after thorough mixing, pour into a circular sheeter, add 8 to 15 times the total volume of oven-dry pulp board water for a second dilution, then pass compressed air through and stir for 3 to 6 minutes, then form wet paper, and after pressing and drying the wet paper sheet, obtain the carrier base paper for later use; S4, Preparation of coating: Add a certain amount of bamboo pulp microfibrillated cellulose to water, stir evenly, and prepare a bamboo pulp microfibrillated cellulose suspension with a mass concentration of 0.5~5%; then place it in an ultrasonic device for ultrasonic dispersion once. After the first ultrasonic dispersion, add a certain amount of PVA particles and titanium dioxide particles to the solution; then heat the mixture and allow it to fully swell, and place it in an ultrasonic device again for a second ultrasonic dispersion; after the second ultrasonic dispersion, heat the mixture to 90~95℃ and stir until the PVA particles are completely dissolved; then place the mixture in an ultrasonic device for a third ultrasonic dispersion. After the third ultrasonic dispersion, let it stand to degas, and obtain the coating. S5, Paper surface coating treatment: The coating prepared in step S4 is applied to the surface of the carrier paper prepared in step S3 by a rod coating method. The coated paper is first dried in an oven at 40~60℃ for 15~30min, and then placed in a constant temperature and humidity test chamber for 20~30h to obtain highly absorbent, low-permeability environmentally friendly decorative paper. In step S4, the first ultrasonic dispersion parameters are: dispersion at 80~100Hz for 10~20min; the second ultrasonic dispersion parameters are: dispersion at 90~120Hz for 10~20min; the third ultrasonic dispersion parameters are: dispersion at 100~150Hz for 10~20min; the amount of PVA particles added is 1~3 times the weight of bamboo pulp microfibrillated cellulose in the coating, and the amount of titanium dioxide particles added is 3~8 times the weight of bamboo pulp microfibrillated cellulose in the coating.

2. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S1, the weight ratio of oven-dried softwood pulp board to oven-dried hardwood pulp board is 3:

2.

3. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S1, the temperature of the soaking water is 30~50℃, and the soaking time is 2~5h.

4. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S1, the beating degree of the mixed slurry is 30°SR.

5. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S1, after pulping, the pulp is filtered and wrung out until the moisture content is 60-90%. Then it is placed in a plastic bag, sealed, and left to stand at room temperature for 3-5 hours to balance the moisture.

6. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S2, the amount of bamboo pulp nanocellulose added is 1% of the total amount of oven-dried pulp board in step S1, and the amount of bamboo pulp microfibrillated cellulose added is 1% of the total amount of oven-dried pulp board in step S1.

7. The method for preparing highly absorbent and low-permeability environmentally friendly decorative base paper using bamboo pulp fiber according to claim 1, characterized in that, In step S5, the relative humidity of the constant temperature and humidity test chamber is 40~60% and the temperature is 20~30℃.

8. Decorative base paper prepared according to any one of claims 1 to 7.

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