Function integrated three-dimensional honeycomb paperboard based on plant fibers and basalt fibers and preparation method

Abstract

According to the function-integrated three-dimensional honeycomb paperboard based on the plant fiber and the basalt fiber and the preparation method, the basalt fiber is modified through the cationic polymer, and the modified basalt fiber with positive charges on the surface is prepared; the modified basalt fibers can be combined with plant fiber slurry more easily, the strength of the function-integrated three-dimensional honeycomb paperboard is improved, and a composite panel is not prone to layering. The function-integrated three-dimensional honeycomb paperboard has the characteristics of light weight, high strength, flame retardance and heat resistance, and is suitable for the fields of buildings, traffic, high-end packaging and the like.

Description

Technical Field

[0001] This invention belongs to the field of paperboard processing technology, and relates to a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber and its preparation method. Background Technology

[0002] Three-dimensional honeycomb paperboard is a sandwich environmentally friendly material made based on the honeycomb structure principle. It has the characteristics of being lightweight, strong in compression, cushioning and shock-absorbing, and recyclable and degradable. It is widely used in packaging and transportation, building decoration, automobile manufacturing, aerospace and other fields.

[0003] Three-dimensional honeycomb paperboard typically consists of a paper core and face sheets located on both sides of the paper core. The base material for preparing the paper core and face sheets is plant fiber paper. However, existing plant fiber paper has the following problems: pure plant fibers have low strength and modulus, resulting in limited mechanical properties and restricting the application of honeycomb paperboard in load-bearing structures; plant fibers are flammable, and although the combustion performance can be improved by adding flame retardants, their mechanical and environmental performance will decrease, and costs will increase; in addition, at higher temperatures above 80°C, plant fibers will become brittle due to water loss, leading to a sharp decline in mechanical properties.

[0004] Basalt fiber is an inorganic fiber made from natural basalt rock through melting and drawing. It possesses excellent properties such as high strength, high modulus, high temperature resistance, corrosion resistance, and inherent flame retardancy, and is also environmentally friendly and non-toxic. However, directly using basalt fiber in papermaking presents several problems: the smooth surface and strong chemical inertness of basalt fiber make it difficult to disperse evenly in water, easily leading to flocculation; the lack of effective chemical bonding or physical interweaving between the basalt fiber surface and plant fibers results in weak adhesion, leading to low paper strength and severe delamination. Therefore, overcoming interfacial compatibility issues and efficiently synergizing the superior properties of basalt fiber with the lightweight and easily formable advantages of plant fibers is key to developing next-generation high-performance honeycomb paperboard. Summary of the Invention

[0005] The purpose of this invention is to provide a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber and its preparation method, so as to solve the problem that basalt fiber is difficult to combine with plant fiber when it is used in papermaking.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This application provides a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber, the preparation method of which includes: S01: Basalt fibers are modified with cationic polymers to obtain modified basalt fibers with positive charges on the surface; S02: Plant fiber pulp and the modified basalt fiber are blended, dispersed, formed, and dried to obtain composite core paper; S03: At least one layer of the composite core paper is laminated between two layers of plant fiber to form a composite panel with at least three layers; S04: After the composite core paper is made into a honeycomb core, the composite panels are hot-pressed and cured on both sides to form a functionally integrated three-dimensional honeycomb paperboard.

[0007] The present invention has the following beneficial effects: (1) In this application, basalt fibers are modified by cationic polymers to prepare modified basalt fibers with positive charges on the surface. The modified basalt fibers are more likely to combine with plant fiber pulp, improve the strength of functional integrated three-dimensional honeycomb paperboard, and the composite panel is less likely to delaminate.

[0008] (2) The functional integrated three-dimensional honeycomb paperboard in this application has a flat crush strength of 450 kPa, a peel strength of 820 N / m, a thermal conductivity as low as 0.045 W / (m·K), and a fire rating of Class A. It has the characteristics of being lightweight, high-strength, flame-retardant, and heat-resistant, and is suitable for fields such as construction, transportation, and high-end packaging. Detailed Implementation

[0009] This application provides a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber, the preparation method of which includes: S01: Basalt fibers are modified with cationic polymers to obtain modified basalt fibers with positive charges on the surface.

[0010] A cationic polymer, polyacrylamide, and silane coupling agent are added to water, and the pH is adjusted to 4.0-5.0 to form a composite modified solution. The amounts of the cationic polymer, polyacrylamide, and silane coupling agent added are 1.0-2.5%, 0.1-0.2%, and 0.3-1.0% of the water mass, respectively. In this application, the cationic polymer is cationic starch, and the silane coupling agent is KH-550 or KH-560.

[0011] Basalt fibers with a length of 3-5 mm were immersed in a composite modification solution and stirred at 70-80℃ for 30-60 minutes. After modification, the basalt fibers were removed, centrifuged to dry, and then dried in an oven at 100-105℃ until constant weight. After slight opening, modified basalt fibers were obtained.

[0012] After basalt fibers are immersed in the composite modification solution, the hydroxyl groups on the surface of the basalt fibers ionize in the aqueous solution, giving the basalt fibers a negative charge. The positive charge on the surface of the cationic polymer can combine with the negative charge on the surface of the basalt fibers to form a stable adsorption layer. Furthermore, the long molecular chains of the cationic polymer become entangled on the surface of the basalt fibers, simultaneously giving the basalt fibers a positive charge. This improves the dispersibility of the basalt fibers and provides sites for the composite of basalt fibers and plant fibers.

[0013] Furthermore, the amide groups on the polyacrylamide molecular chain can form strong hydrogen bonds with the hydroxyl groups on the surface of basalt fibers, thus fixing the molecular chain on the basalt fiber surface. Simultaneously, the long molecular chains of polyacrylamide can form molecular bridges between adjacent basalt fibers, reducing fiber agglomeration. When the silane coupling agent dissolves in water, it hydrolyzes to generate silanol groups. These silanol groups can undergo dehydration condensation with the hydroxyl groups on the basalt fiber surface to form Si-O-Si covalent bonds, thereby modifying the basalt fibers.

[0014] S02: Plant fiber pulp and the modified basalt fiber are blended, dispersed, formed, and dried to obtain composite core paper.

[0015] Plant fiber pulp and modified basalt fiber were blended and dispersed at an oven-dry weight ratio of 95:5-80:20 to form a composite pulp. This composite pulp was then decomposed in a deflator for 10 minutes, formed on a cylinder paper machine, and dried to a basis weight of 120 g / m³. 2 Composite core paper. In this application, the plant fiber pulp includes one or more of softwood pulp, hardwood pulp, bamboo pulp, straw pulp, or recycled waste paper pulp.

[0016] The modified basalt fibers carry a positive charge on their surface, while the plant fiber pulp carries a negative charge. When mixed, they not only neutralize the charges through electrostatic adsorption, reducing electrostatic repulsion between the two fibers and preventing plant fiber flocculation, but also act as charge bridges connecting adjacent plant fibers, ensuring uniform dispersion of the modified basalt fibers and preventing agglomeration. Secondly, the residual hydroxyl groups on the surface of the modified basalt fibers can bond with the hydroxyl groups on the plant fibers, enhancing the interfacial bonding between the modified basalt fibers and plant fibers and preventing interfacial delamination in both dry and wet conditions. Furthermore, both the modified basalt fibers and plant fibers are fibrous; during stirring, the two fiber bundles intertwine and entangle, forming a three-dimensional network structure of a rigid basalt skeleton and flexible plant fiber filling. This improves the crack resistance of the composite panel and disperses stress concentration. Therefore, this application achieves a perfect fusion of basalt fibers and plant fibers at the microscopic level through charge neutralization, chemical bonding, and the construction of a three-dimensional network, thereby enabling the preparation of high-quality functional integrated honeycomb paperboard.

[0017] S03: Using multi-layer papermaking technology, at least one layer of composite core paper is laminated between two layers of plant fiber, thereby forming a composite panel with at least three layers, the outer layer being a pure plant fiber layer and the inner layer being a composite core paper. The basis weight of the composite core paper is 30-50% of the basis weight of the composite panel.

[0018] After the composite panel is formed, a fire-retardant coating can be applied to the outside of the composite panel to achieve fire resistance. In this application, a fire-retardant coating prepared by spraying ammonium polyphosphate, pentaerythritol and melamine in a mass ratio of (2-4):(1-2):(1-2) can be applied to the surface of the composite panel and used after curing; alternatively, the composite panel can be immersed in a 5% sodium silicate solution and cured at 110-120℃ before use.

[0019] S04: After the composite core paper is made into a honeycomb core, the composite panels are hot-pressed and cured on both sides to form a functionally integrated three-dimensional honeycomb paperboard.

[0020] The composite core paper is prepared into a honeycomb core with a pore size of 8-10 mm through processes such as coating, stacking, slitting, and stretching. Composite panels are then glued to both sides of the honeycomb core using an inorganic flame-retardant adhesive. The core is then hot-pressed and cured for 10-30 minutes at a curing temperature of 180-220℃ and a pressure of 1.0-2.0 MPa to form a functionally integrated three-dimensional honeycomb paperboard.

[0021] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0022] Example 1 This application provides a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber. The preparation method of the three-dimensional honeycomb paperboard includes: S101: Add 2.0 kg of cationic starch with a degree of substitution of 0.04, 0.2 kg of polyacrylamide, and 1.0 kg of silane coupling agent KH-550 to 100 kg of water, and adjust the pH to 4.5 to form a composite modification solution. Immerse 10 kg of basalt fibers with a length of 3 mm in the composite modification solution and stir at 70℃ for 45 min. After modification, remove the basalt fibers, centrifuge to dry, and then dry them in an oven at 105℃ to constant weight. After slight opening, obtain modified basalt fibers.

[0023] S102: Softwood pulp and modified basalt fiber are blended and dispersed at an oven-dry weight ratio of 80:20, and diluted to a concentration of 1.5% to form a composite pulp. This composite pulp is then decomposed in a deflator for 10 minutes, formed on a cylinder paper machine, and dried to a basis weight of 120 g / m³. 2 Composite core paper.

[0024] S103: Employing multi-layer papermaking technology, a composite core paper is laminated between two layers of softwood pulp, thus forming a three-layer composite panel with an outer pure plant fiber layer and an inner composite core paper layer. The basis weight of the composite core paper is 50% of that of the composite panel, and the basis weight of the composite panel is 250 g / m³. 2 After drying, the composite panel is immersed in a 5% sodium silicate solution, then removed and cured at 120°C to form a composite panel with a dense inorganic fire-retardant coating on the surface.

[0025] S104: A honeycomb core with an 8mm pore size is prepared by coating, stacking, slitting, and stretching composite core paper. Composite panels are glued to both sides of the honeycomb core using inorganic flame-retardant adhesive. The core is then hot-pressed and cured for 20 minutes at a curing temperature of 180℃ and a pressure of 1.0MPa to form a functional integrated three-dimensional honeycomb paperboard.

[0026] Example 2 This application provides a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber. The preparation method of the three-dimensional honeycomb paperboard includes: S201: Add 2.5 kg of cationic starch with a degree of substitution of 0.04, 0.1 kg of polyacrylamide, and 0.8 kg of silane coupling agent KH-560 to 100 kg of water, and adjust the pH to 4.0 to form a composite modification solution. Immerse 10 kg of basalt fibers with a length of 5 mm in the composite modification solution and stir at 75°C for 60 min. After modification, remove the basalt fibers, centrifuge to dry, and then dry them in an oven at 105°C until constant weight. After slight opening, obtain modified basalt fibers.

[0027] S202: Recycled waste paper pulp and modified basalt fiber are blended and dispersed at an oven-dry mass ratio of 75:25, and diluted to a concentration of 1.8% to form a composite pulp. This composite pulp is then decomposed in a deflator for 10 minutes, formed on a cylinder paper machine, and dried to a basis weight of 125 g / m³. 2 Composite core paper.

[0028] S203: Employing multi-layer papermaking technology, a composite core paper is laminated between two layers of recycled waste paper pulp, thus forming a three-layer composite panel with an outer layer of pure plant fiber and an inner layer of composite core paper. The basis weight of the composite core paper is 30% of the basis weight of the composite panel, and the basis weight of the composite panel is 280 g / m³. 2 After drying, a fire-retardant coating is sprayed onto the surface of the composite panel, which is prepared by mixing ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 2:1:1. The coating is then cured before use.

[0029] S204: A honeycomb core with a pore size of 10mm is prepared by coating, stacking, slitting, and stretching composite core paper. Composite panels are glued to both sides of the honeycomb core using inorganic flame-retardant adhesive. The core is then hot-pressed and cured for 10 minutes at a curing temperature of 220℃ and a pressure of 2.0MPa to form a functional integrated three-dimensional honeycomb paperboard.

[0030] Example 3 This application provides a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber. The preparation method of the three-dimensional honeycomb paperboard includes: S301: Add 1.0 kg of cationic starch with a degree of substitution of 0.04, 0.2 kg of polyacrylamide, and 0.6 kg of silane coupling agent KH-550 to 100 kg of water, and adjust the pH to 5.0 to form a composite modification solution. Immerse 10 kg of basalt fibers with a length of 4 mm in the composite modification solution and stir at 80℃ for 30 min. After modification, remove the basalt fibers, centrifuge to dry, and then dry them in an oven at 100℃ until constant weight. After slight opening, obtain modified basalt fibers.

[0031] S302: Hardwood pulp and modified basalt fiber are blended and dispersed at an oven-dry mass ratio of 95:5, and diluted to a concentration of 1.5% to form a composite pulp. This composite pulp is then decomposed in a deflator for 10 minutes, formed on a cylinder paper machine, and dried to a basis weight of 125 g / m³. 2 Composite core paper.

[0032] S303: Employing multi-layer papermaking technology, a composite core paper is laminated between two layers of hardwood pulp, thus forming a three-layer composite panel with an outer pure plant fiber layer and an inner composite core paper layer. The basis weight of the composite core paper is 45% of the basis weight of the composite panel, and the basis weight of the composite panel is 260 g / m³. 2 The dried composite panel is immersed in a 5% sodium silicate solution and cured at 120°C before use.

[0033] S304: A honeycomb core with an 8mm pore size is prepared by coating, stacking, slitting, and stretching composite core paper. Composite panels are glued to both sides of the honeycomb core using inorganic flame-retardant adhesive. The core is then hot-pressed and cured for 20 minutes at a curing temperature of 200℃ and a pressure of 1.5MPa to form a functional integrated three-dimensional honeycomb paperboard.

[0034] Comparative Example 1 This application provides a comparative example of a common honeycomb paperboard, the face sheet and core paper of which are made entirely from 100% softwood pulp, without any added reinforcement or flame retardant treatment, and are prepared using ordinary starch adhesive.

[0035] Comparative Example 2 This application provides a honeycomb paperboard as a comparative example, which is the same as that in Comparative Example 1, except that 30% aluminum hydroxide powder is added to the softwood pulp as a flame retardant.

[0036] Comparative Example 3 This application provides a comparative example of a honeycomb paperboard, which is prepared by the same method as in Example 1, except that the basalt fibers are unmodified.

[0037] Comparative Example 4 This application provides a comparative example of a honeycomb paperboard, wherein the core paperboard is prepared from 100% softwood pulp, and the face panel is the composite face panel of Example 1.

[0038] The density, flat crush strength, peel strength, fire rating (GB-8624), and thermal conductivity of the honeycomb paperboard in Examples 1-3 and Comparative Examples 1-4 were tested respectively, and Table 1 was obtained. In this paper, Class A is non-combustible, Class B1 is flame-retardant, Class B2 is combustible, and Class B3 is flammable.

[0039] Table 1: Performance Test Data As shown in Table 1, compared with Comparative Examples 1-4, the honeycomb paperboards prepared in Examples 1-3 have significantly improved flat crush strength and peel strength, lower thermal conductivity, and can achieve a fire rating of Class A. This indicates that the pulp obtained by mixing modified basalt fiber and plant fiber in the embodiments of this application can prepare a lightweight, high structural strength, heat-insulating and fire-resistant Class A three-dimensional honeycomb paperboard.

[0040] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber, characterized in that, include: Cationic polymers were used to modify basalt fibers to obtain modified basalt fibers with positive charges on the surface. Plant fiber pulp and the modified basalt fiber are blended, dispersed, formed, and dried to obtain composite core paper; At least one layer of the composite core paper is laminated between two layers of plant fiber to form a composite panel with at least three layers. After the composite core paper is made into a honeycomb core, the composite panels are hot-pressed and cured on both sides to form a functionally integrated three-dimensional honeycomb paperboard.

2. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, The modification of basalt fibers using cationic polymers includes: Cationic polymer, polyacrylamide, and silane coupling agent are added to water, and the pH is adjusted to 4.0-5.0 to form a composite modified solution. The basalt fiber was immersed in the composite modification liquid and stirred at 70-80℃ for 30-60 minutes; after centrifugation and drying to constant weight, the modified basalt fiber was obtained.

3. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 2, characterized in that, The cationic polymer, the polyacrylamide, and the silane coupling agent are added at amounts of 1.0-2.5%, 0.1-0.2%, and 0.3-1.0% of the water mass, respectively.

4. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 2, characterized in that, The cationic polymer is cationic starch, and the silane coupling agent is KH-550 or KH-560.

5. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, The oven-dry mass ratio of the plant fiber pulp to the modified basalt fiber is 95:5-80:

20.

6. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, The basis weight of the composite core paper is 30-50% of the basis weight of the composite panel.

7. The method for preparing the functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, The composite panel is immersed in a sodium silicate solution, cured at 110-120°C, and then composited with the honeycomb core.

8. The method for preparing a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, Fire-retardant coating is sprayed onto the surface of the composite panel, and after curing, it is combined with the honeycomb core.

9. The method for preparing a functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber according to claim 1, characterized in that, The hot-press curing temperature is 180-220℃, the pressure is 1.0-2.0MPa, and the time is 10-30min.

10. The functional integrated three-dimensional honeycomb paperboard based on plant fiber and basalt fiber prepared by the preparation method according to any one of claims 1-9.

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