Bamboo longitudinal and wood transverse composite whole container bottom plate

Abstract

The invention discloses a bamboo longitudinal and wood transverse composite whole container bottom plate and a preparation method thereof, and belongs to the field of bamboo-wood composite materials. The bottom plate is of a seven-layer alternate paving structure and is formed by compositing transverse wood veneer layers and longitudinal radial bamboo curtain layers, wood veneers are made of lignin modified polyurethane adhesive (reinforced by nano-silicon dioxide), and bamboo curtains are made of bamboo fiber nano-crystal reinforced soybean protein adhesive (cross-linked by genipin). Through continuous paving, fixed-length saw cutting and a'cold-in-cold-out 'hot pressing process (the pressure is 1.5-8.0 MPa, and the temperature is 140-220 DEG C), whole-piece production of any length is achieved. According to the technology, the bamboo-wood interface bonding problem is solved, the bending strength reaches 120 MPa, the interlayer shear strength is 7.8 MPa, the strength retention rate after damp-heat aging resistance is 90%, the formaldehyde emission is smaller than or equal to 0.05 mg / m < 3 >, the bio-based carbon content is 85%, high strength, weather resistance and environment friendliness are achieved, a traditional spliced container bottom plate can be replaced, the material utilization rate is increased by 20% or above, and the manufacturing cost is remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the field of preparation of bamboo-wood composite materials, and particularly discloses a bamboo longitudinal and wood transverse composite integral container bottom plate. Background Art

[0002] Plant fiber composite materials (such as particleboard, medium / high density fiberboard, plywood, etc.) have been widely used in furniture manufacturing and architectural decoration due to their wide range of raw material sources and convenient processing. However, such materials generally have insufficient mechanical properties, especially low bending strength and load-bearing capacity, which makes it difficult to meet the use requirements of heavy-load scenarios (such as container floors). In container manufacturing, traditional processes require the base material to be cut into specific sizes before splicing, which not only leads to low material utilization and high processing costs, but also easily generates stress concentration at the joints, affecting the overall structural stability of the floor. Therefore, the development of integrated, high-performance container floors has become an urgent need in the industry.

[0003] As a fast-growing, renewable resource, bamboo has attracted much attention due to its unique biological properties. For example, the growth cycle of moso bamboo is only 3 to 5 years, and my country's bamboo forest area grows by an average of 3% annually, with resource reserves ranking first in the world. Bamboo's unique microstructure (such as its hollow structure and green-yellow gradient distribution) gives it excellent tensile strength and toughness, making it an ideal raw material for replacing wood. Research has shown that the directional arrangement of bamboo's longitudinal fibers can significantly improve the mechanical properties of composite materials, providing a new direction for the development of high-strength container floors.

[0004] However, optimizing the performance of bamboo-wood composites faces two major challenges: First, the interfacial bonding strength between bamboo and wood is insufficient. Traditional adhesives (such as phenolic resins and urea-formaldehyde resins) have poor permeability into bamboo and limited resistance to moisture and heat aging, which can easily lead to interlaminar delamination. Second, existing adhesives mostly rely on petrochemical raw materials, are not environmentally friendly, and cannot meet the trend of green manufacturing. In addition, the surface of bamboo is rich in silica and wax layers, which further hinder the effective infiltration of adhesives. Therefore, there is an urgent need to develop a special adhesive system tailored to the interfacial characteristics of bamboo and wood, and to improve bonding strength and environmental adaptability through molecular design while taking into account sustainability. Summary of the Invention

[0005] To address the aforementioned existing technical issues, this invention discloses a composite, integrated container floor made of bamboo and wood. For the wood veneer, a lignin-modified polyurethane adhesive is used, leveraging lignin's natural polar groups to enhance wood permeability, while nanosilica improves shear resistance. For the bamboo curtain, a bamboo fiber-reinforced soy protein adhesive is designed, leveraging the synergistic effect of bamboo fiber nanocrystals and soy protein to enhance the interfacial bonding strength and moisture and heat stability of the bamboo material. This technology not only solves the interfacial bonding challenges of bamboo-wood composite materials but also significantly reduces the adhesive's carbon footprint, providing technical support for the industrialized production of integrated container floors.

[0006] The present invention includes the following technical solutions:

[0007] A bamboo longitudinal and wood transverse composite integral container bottom plate is prepared by the following steps:

[0008] (1) Material preparation process

[0009] Prepare radial bamboo curtains, and carry out glue dipping and drying to make longitudinal layer raw materials; prepare wood veneer, and carry out glue dipping and drying to make transverse layer raw materials;

[0010] (2) Slab paving

[0011] The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure;

[0012] Each layer of the horizontal layer of raw materials (wood veneer) is a single wood veneer, and each layer of the longitudinal layer of raw materials (radial bamboo curtains) is laid with a plurality of radial bamboo curtains, each bamboo curtain is horizontally butted, and no overlapping seams should appear on any vertical section of the slab; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is 30 to 50 meters;

[0013] (3) Slab fixed length sawing

[0014] According to the width of the container bottom plate, the slab is cut into slabs of full length by band saw;

[0015] (4) Pre-compression exhaust

[0016] The integrated slab is sent to a cold press for pre-pressing to remove gas from the slab and compact it to reduce the thickness of the slab;

[0017] (5) Hot pressing

[0018] The pre-pressed slab is sent to a hot press for hot pressing to produce a bamboo longitudinal and wood transverse composite whole container floor rough board;

[0019] The thickness of the bamboo longitudinal and wood transverse composite container bottom plate is 20 to 50 mm.

[0020] (6) Vertical and horizontal trimming

[0021] The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

[0022] Furthermore, in the above-mentioned bamboo longitudinal and wood transverse composite integrated container bottom plate, in step (1), the radial bamboo curtain and wood veneer are subjected to glue dipping treatment; the mass ratio of the glue dipping amount: the adhesive solid amount and the absolute dry wood veneer amount / the absolute dry bamboo curtain amount is (3-12):100.

[0023] Furthermore, in the above-mentioned bamboo longitudinal and wood transverse composite integrated container bottom plate, in step (5), the hot press is an intermittent single-layer hot press or an intermittent multi-layer hot press;

[0024] The hot pressing method is a "cold in - cold out" hot pressing molding process, specifically "feeding - heating - heat preservation and hot pressing - cooling - discharging" process;

[0025] The hot pressing process is divided into three stages: pressure increase, pressure holding, and unloading. During the pressure holding stage, the unit pressure of the hot press is 1.5~8.0MPa, and the temperature of the hot pressing plate is 140~220℃.

[0026] Furthermore, in the above bamboo longitudinal and wood transverse composite integrated container bottom plate, in step (1), the preparation method of the wood veneer is:

[0027] Saw the logs into the length of the wood veneer, process them into veneer strips through a peeling machine, or splice them into longer veneer strips through a veneer shearing machine and a splicing machine; dip the veneer strips into glue; and place the dipped veneer strips in a dryer for drying;

[0028] Specific process parameters:

[0029] Veneer strip width: the length of the wood veneer; veneer strip length: 30~50m;

[0030] Glue impregnation amount: The mass ratio of adhesive solids to absolute dry wood veneer is (3-12):100;

[0031] The moisture content of wood veneer after drying is 2% to 8%.

[0032] Furthermore, the above-mentioned bamboo longitudinal and wood transverse composite integrated container bottom plate, wherein the adhesive of the wood veneer is a lignin-modified polyurethane adhesive, is prepared by the following steps:

[0033] (1) mixing sodium lignin sulfonate and epichlorohydrin in a mass ratio of 1:(0.3-0.8), reacting at 60-80° C. for 2-4 hours to generate a lignin-based epoxy prepolymer;

[0034] (2) mixing the prepolymer and polyisocyanate (MDI) in a mass ratio of 1:(1.5-2.5), adding 0.5%-2% of a nano-silicon dioxide dispersion, and stirring at 50-70° C. for 1-3 hours to prepare a lignin-modified polyurethane adhesive;

[0035] (3) The viscosity of the adhesive is 500 to 1500 mPa·s, the curing temperature is 100 to 140°C, and the curing time is 10 to 30 minutes.

[0036] Furthermore, in the above-mentioned bamboo longitudinal and wood transverse composite integrated container bottom plate, the particle size of the nano-silicon dioxide dispersion is 10 to 50 nm, and the silicon dioxide content in the dispersion is 10% to 20%.

[0037] Furthermore, in the above bamboo longitudinal and wood transverse composite integrated container bottom plate, in step (1), the preparation method of the radial bamboo curtain is:

[0038] The original bamboo segment is split into arc-shaped bamboo blanks, which are then split into radial strips by a radial strip splitting machine, and the radial strips are woven into a bamboo curtain of continuous length by a bamboo curtain weaving machine; the bamboo curtain is then placed in a glue dipping tank for dipping; and the glued bamboo curtain is placed in a dryer for drying;

[0039] Specific process parameters:

[0040] The width of the radial bamboo curtain is the natural length of the bamboo strips; the length of the radial bamboo curtain is 30 to 50 meters;

[0041] Glue impregnation amount: the mass ratio of adhesive solid amount to dry bamboo curtain amount is (3-12):100;

[0042] The moisture content of bamboo curtain after drying: 2%~8%.

[0043] Furthermore, the above-mentioned bamboo longitudinal and wood transverse composite integrated container floor, wherein the adhesive of the radial bamboo curtain is bamboo fiber reinforced soybean protein adhesive, is prepared by the following steps:

[0044] (1) Soy protein isolate and deionized water are mixed in a mass ratio of 1:(3-5), bamboo fiber nanocrystals accounting for 5%-15% of the weight of the soy protein are added, and the mixture is stirred at a pH of 9-11 and a temperature of 50-70° C. for 2-4 hours to form a homogeneous gel;

[0045] (2) adding genipin, a cross-linking agent, at a concentration of 0.1% to 0.5% by weight of the total glue solution, and continuing stirring for 30 to 60 minutes;

[0046] (3) The viscosity of the adhesive is 800 to 2000 mPa·s, the curing temperature is 120 to 160°C, and the curing time is 15 to 40 minutes.

[0047] Furthermore, the preparation method of the bamboo fiber nanocrystals in the above-mentioned bamboo longitudinal and wood transverse composite integrated container bottom plate is as follows:

[0048] (1) The bamboo fiber is hydrolyzed with sulfuric acid (concentration 60% to 70%, temperature 50 to 70°C) for 2 to 4 hours;

[0049] (2) After centrifugal washing to neutrality, the mixture was ultrasonically dispersed in deionized water to obtain a bamboo fiber nanocrystal suspension with a particle size of 20 to 100 nm.

[0050] The invention also discloses the use of the bamboo longitudinal and wood transverse composite integrated container bottom plate in preparing the container bottom plate.

[0051] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0052] 1. Mechanical properties are significantly improved to meet heavy load requirements

[0053] Through the composite structure design of bamboo curtain longitudinal fiber directional reinforcement and wood veneer transverse support, combined with a special adhesive system, a breakthrough in mechanical properties has been achieved:

[0054] Bending strength: Example 1 has a longitudinal bending strength of 120 MPa, which is 30% higher than that of Comparative Example 2 (commercially available MDI glue), and a transverse bending strength of 45 MPa, which is better than traditional plywood (usually less than 30 MPa) and fully meets the strength requirement of the container bottom plate with a dynamic load of 30 tons.

[0055] Interlaminar shear strength: Example 1 reaches 7.8 MPa, a 56% improvement over Comparative Example 2 (5.0 MPa), effectively preventing interlaminar delamination. This advantage stems from the nano-silica reinforcement of the lignin-modified polyurethane adhesive and the chemical crosslinking of bamboo fiber nanocrystals with soy protein, creating a dual "glue-nail-fiber" reinforcement effect.

[0056] 2. Outstanding environmental performance, in line with the trend of green manufacturing

[0057] Formaldehyde emission: Example 1 is only 0.05 mg / m 3 , which is much lower than the E0 standard of GB / T 17657-2013 (≤0.5mg / m 3 ), completely solving the formaldehyde pollution problem of traditional phenolic / urea-formaldehyde glue.

[0058] Bio-based carbon content: The adhesive in Example 1 boasts 85% bio-based carbon, more than three times the 20% in Comparative Example 1, reducing reliance on petrochemical resources and lowering its carbon footprint by 60%. This achievement is attributed to the design of a fully bio-based adhesive system: the lignin-modified polyurethane adhesive replaces 50% of petroleum-based raw materials with renewable lignin, while the bamboo fiber-reinforced soy protein adhesive is derived entirely from plant resources.

[0059] 3. Optimization of interface bonding strength and moisture and heat resistance stability

[0060] Resistance to moist heat aging: After aging for 168 hours at 70°C / 85%RH, Example 1 has a flexural strength retention rate of 90% and an interlaminar shear strength retention rate of 85%, which is significantly improved compared to Comparative Example 2 (75% / 70%).

[0061] The core mechanism may be that the epoxy groups in the lignin-modified polyurethane adhesive form covalent bonds with the wood hydroxyl groups, nano-silica fills the pores and inhibits the penetration of water molecules; bamboo fiber nanocrystals strengthen the soybean protein adhesive network through hydrogen bonds and mechanical interlocking, and genipin cross-linking further stabilizes the protein molecular conformation and prevents the adhesive layer from degrading in a hot and humid environment.

[0062] 4. Improve both material utilization and production efficiency

[0063] Whole-sheet production: Through the 30-50m continuous slab strip laying and fixed-length sawing process, the traditional splicing process is reduced, the material utilization rate is increased from 70% to more than 90%, and the processing cost is reduced by 15% to 20%.

[0064] Process compatibility: The "cold in - cold out" hot pressing technology avoids pre-curing of the slab, increases the yield to 98%, and is suitable for single-layer / multi-layer hot pressing machines, with production efficiency twice that of traditional processes.

[0065] 5. Resource sustainability and economic advantages

[0066] Efficient use of bamboo materials: Radial bamboo curtains retain the natural orientation of bamboo fibers, with a bamboo utilization rate of 80% (traditional technology is only 50%). Combined with fast-growing bamboo resources (3 to 5 years to mature), the raw material cost is reduced by 30%.

[0067] Enhanced structural stability: The seven-layer orthogonal composite structure eliminates stress concentration, and the deformation rate of the whole plate is less than 0.5% (traditional spliced ​​plates are greater than 1.5%), extending the service life of the container bottom plate to more than 10 years.

[0068] In summary, the present invention overcomes the industry pain points of weak interface, poor weather resistance, and formaldehyde pollution of bamboo-wood composite materials through the three-in-one optimization of "structural design-adhesive innovation-process integration", provides a high-performance, low-cost, and environmentally friendly alternative for container bottom plates, and promotes the large-scale application of bamboo resources in high-value-added fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic diagram of the structure of a bamboo longitudinal and wood transverse composite container bottom plate of the present invention;

[0070] Figure 2 This is a process flow chart of a bamboo longitudinal and wood transverse composite integrated container bottom plate of the present invention;

[0071] Figure 3 This is a schematic cross-sectional view of a bamboo longitudinal and wood transverse composite integral container bottom plate of the present invention;

[0072] Figure 4 This is a schematic diagram of the continuous assembly of a bamboo longitudinal and wood transverse composite integral container bottom plate of the present invention. DETAILED DESCRIPTION

[0073] like Figure 1 As shown, the bamboo longitudinal and wood transverse composite integrated container bottom plate of the present invention is composed of a seven-layer structure of wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer, 1, 3, 5, and 7 are transverse wood veneers, and 2, 4, and 6 are longitudinal radial bamboo curtains.

[0074] Manufacturing method of bamboo longitudinal and wood transverse composite integrated container floor: 1. Material preparation process. Prepare radial bamboo curtains, and carry out glue dipping and drying treatments respectively to make transverse layer raw materials; prepare wood veneers, and carry out drying and gluing treatments to make longitudinal layer raw materials. 2. Slab paving. From bottom to top, the wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid to form a seven-layer structure of arbitrary length slab strips; each layer of the transverse layer raw materials (wood veneer) is a continuously laid wood veneer, such as Figure 4 As shown; the longitudinal layer material (radial bamboo curtain) is laid with several radial bamboo curtains on each layer, each bamboo curtain is horizontally butted and no overlapping seams shall appear on any vertical section of the slab. Figure 3 As shown; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is 30 to 50 meters. 3. Slab fixed-length sawing. According to the width of the container floor, the slab strip is sawed into whole slabs. 4. Pre-pressing and exhaust. The whole slab is sent to the cold press for pre-pressing to remove the gas inside the slab and compact it to reduce the thickness of the slab; 5. Hot pressing. The slab is sent to a single-layer or multi-layer hot press for hot pressing to make a bamboo longitudinal and wood transverse composite raw board. 6. Longitudinal and transverse trimming. The hot-pressed raw board is trimmed to form a bamboo longitudinal and wood transverse composite whole container floor.

[0075] In a preferred embodiment of the present invention, the longitudinal layer of raw material, the radial bamboo curtain, is dipped in glue at a weight ratio of 3-12:100 for the glue: adhesive solids: bone-dry bamboo curtain. The transverse layer of raw material, the wood veneer, is coated with glue at a weight ratio of 3-12:100 for the glue: adhesive solids: bone-dry veneer. The adhesives used are commonly used in the wood-based panel industry, such as monoisocyanate (MDI), phenolic resin (PF), urea-formaldehyde (UF), polyurethane, starch, lignin, tannin, and cellulose.

[0076] The hot press can be an intermittent single-layer or multi-layer hot press. The hot pressing method is a "cold in, cold out" hot pressing process, specifically "feeding - heating - holding hot pressing - cooling - discharge." The hot pressing process consists of three stages: pressurization, holding pressure, and unloading. During the holding pressure stage, the unit pressure of the hot press is 1.5-8.0 MPa, and the hot pressing plate temperature is 140-220°C.

[0077] When manufacturing the bamboo longitudinal and wood transverse composite integral container bottom plate, the radial bamboo curtain of the longitudinal layer raw material and the wood veneer of the transverse layer raw material can be purchased on the market, or can be made from original bamboo or log.

[0078] like Figure 2 As shown, a bamboo longitudinal and transverse composite container floor is manufactured using radial bamboo curtains and wood veneers through continuous layering, slab cutting to fixed length, pre-pressing and exhausting, hot pressing, and sawing and trimming. The method of the present invention for producing a bamboo longitudinal and transverse composite container floor includes the following steps:

[0079] S1. Material preparation process

[0080] S1.1 Preparation, impregnation and drying of radial bamboo curtains

[0081] The original bamboo segment is split into arc-shaped bamboo blanks, which are then split into radial strips by a radial strip splitting machine. The radial strips are then passed through a bamboo curtain weaving machine to form a continuous length of bamboo curtain. The bamboo curtain is then placed in a glue dipping tank for dipping in glue. The glued bamboo curtain is then placed in a dryer for drying.

[0082] Specific process parameters:

[0083] The width of the radial bamboo curtain is the natural length of the bamboo strips; the length of the radial bamboo curtain is 30 to 50 meters;

[0084] Glue impregnation amount: the weight ratio of adhesive solid amount to dry bamboo curtain amount is (3-12):100;

[0085] The adhesives are commonly used adhesives in the wood-based panel industry, such as isocyanate glue (MDI), phenolic resin glue (PF), urea-formaldehyde resin glue (UF), polyurethane glue, starch glue, lignin glue, tannin glue, and cellulose glue.

[0086] The moisture content of bamboo curtain after drying: 2%~8%.

[0087] S1.2 Preparation of wood veneer

[0088] Saw the logs into the length of the wood veneer, process them into veneer strips through a peeling machine, or splice them into longer veneer strips through a veneer shearing machine and a splicing machine; dip or coat the veneer strips with glue; and dry the dipped or coated veneer strips in a dryer;

[0089] Specific process parameters:

[0090] Veneer strip width: the length of the wood veneer; veneer strip length: 30~50m;

[0091] Glue impregnation amount: The weight ratio of adhesive solids to dry wood veneer is (3-12):100;

[0092] The adhesives are commonly used adhesives in the wood-based panel industry, such as isocyanate glue (MDI), phenolic resin glue (PF), urea-formaldehyde resin glue (UF), polyurethane glue, starch glue, lignin glue, tannin glue, and cellulose glue.

[0093] The moisture content of wood veneer after drying is 2% to 8%.

[0094] S2. Slab paving

[0095] The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure;

[0096] Each layer of the horizontal layer material (wood veneer) is a wood veneer, and each layer of the vertical layer material (radial bamboo curtain) is laid with a number of radial bamboo curtains. Each bamboo curtain is horizontally butted and no overlapping seams should appear on any vertical section of the slab. Figure 4 As shown; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is any length.

[0097] S3. Slab cut to length

[0098] According to the width of the container bottom plate, the slab is cut into whole slabs by band saw.

[0099] S4. Pre-compression exhaust

[0100] The integrated slab is sent to a cold press for pre-pressing to remove the gas inside the slab and compact it to reduce the thickness of the slab.

[0101] S5.Hot pressing

[0102] The paved slab is sent to a hot press for hot pressing to form a bamboo longitudinal and wood transverse composite integral container floor rough board; the bamboo longitudinal and wood transverse composite integral container floor rough board has a thickness of 20 to 50 mm;

[0103] According to the different requirements of the end product, different hot pressing processes are used for hot pressing forming.

[0104] There are two types of heat presses:

[0105] (1) Intermittent single-layer hot press

[0106] This type of hot press has only one opening layer, and the upper and lower hot pressing plates are rigid heat-conducting carriers. The slab is first fed into the hot press through a plate loader, and the upper and lower hot pressing plates are closed to complete the hot pressing forming process in one hot pressing cycle; then, the upper and lower hot pressing plates are opened, and the formed plate is taken out through a plate unloader.

[0107] (2) Intermittent multi-layer hot press

[0108] This type of hot press has multiple layers, generally 8 to 40 layers. Its hot pressing principle is the same as that of the intermittent single-layer hot press, but the production efficiency is increased several times, but the cost of the press, loader and unloader also increases accordingly.

[0109] (3) Hot pressing process and parameters

[0110] 1) Hot pressing method

[0111] The hot pressing method uses a "cold in-cold out" hot pressing process, specifically consisting of "feeding - heating - hot pressing with insulation - cooling - discharge." This "cold in-cold out" process allows the slab to shrink rapidly after high-temperature processing, expelling air between individual layers of the slab and preventing delamination and bubbling in the finished sheet. It also prevents sudden surface heating of the slab, which could create a "pre-cured surface layer" without complete compaction.

[0112] 2) Hot pressing process

[0113] The hot pressing process consists of three stages: pressure increase, pressure holding, and unloading. The pressure increase stage is to quickly compact the slab and increase its density. The pressure holding stage is to transfer the heat from the pressing plate to the slab, accelerating the curing of the adhesive and forming glue nails, while further softening the bamboo and wood materials at the glass temperature to bond. The unloading stage is to slowly release the internal stress and gas in the slab to prevent delamination of the rough board.

[0114] The unit pressure of the hot press during the holding stage is 1.5~8MPa.

[0115] The temperature of the hot pressing plate of the hot press is generally 140~220℃.

[0116] S6. Vertical and horizontal trimming

[0117] The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

[0118] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0119] Table 1 List of raw materials

[0120]

[0121] Table 2 Instrument and Equipment List

[0122]

[0123]

[0124] Process Example 1

[0125] A bamboo longitudinal and wood transverse composite integral container bottom plate is prepared by the following steps:

[0126] (1) Material preparation process

[0127] Prepare radial bamboo curtains, and carry out glue dipping and drying to make longitudinal layer raw materials; prepare wood veneer, and carry out glue dipping and drying to make transverse layer raw materials;

[0128] (2) Slab paving

[0129] The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure;

[0130] Each layer of the horizontal layer of raw materials (wood veneer) is a single wood veneer, and each layer of the longitudinal layer of raw materials (radial bamboo curtains) is laid with a plurality of radial bamboo curtains, each bamboo curtain is horizontally butted, and no overlapping seams should appear on any vertical section of the slab; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is 30m;

[0131] (3) Slab fixed length sawing

[0132] According to the width of the container bottom plate, the slab is cut into slabs of full length by band saw;

[0133] (4) Pre-compression exhaust

[0134] The integrated slab is sent to a cold press for pre-pressing to remove gas from the slab and compact it to reduce the thickness of the slab;

[0135] (5) Hot pressing

[0136] The pre-pressed slab is sent to a hot press for hot pressing to produce a bamboo longitudinal and wood transverse composite integral container floor rough plate; the hot press is an intermittent single-layer hot press or an intermittent multi-layer hot press;

[0137] The hot pressing method is a "cold in - cold out" hot pressing molding process, specifically "feeding - heating - heat preservation and hot pressing - cooling - discharging" process;

[0138] The hot pressing process is divided into three stages: pressure increase, pressure holding, and unloading. During the pressure holding stage, the unit pressure of the hot press is 1.5MPa and the temperature of the hot pressing plate is 140℃.

[0139] The thickness of the bamboo longitudinal and wood transverse composite container bottom plate is 20mm;

[0140] (6) Vertical and horizontal trimming

[0141] The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

[0142] Process Example 2

[0143] A bamboo longitudinal and wood transverse composite integral container bottom plate is prepared by the following steps:

[0144] (1) Material preparation process

[0145] Prepare radial bamboo curtains, and carry out glue dipping and drying to make longitudinal layer raw materials; prepare wood veneer, and carry out glue dipping and drying to make transverse layer raw materials;

[0146] (2) Slab paving

[0147] The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure;

[0148] Each layer of the horizontal layer of raw materials (wood veneer) is a single wood veneer, and each layer of the longitudinal layer of raw materials (radial bamboo curtains) is laid with a plurality of radial bamboo curtains, each bamboo curtain is horizontally butted, and no overlapping seams should appear on any vertical section of the slab; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is 40m;

[0149] (3) Slab fixed length sawing

[0150] According to the width of the container bottom plate, the slab is cut into slabs of full length by band saw;

[0151] (4) Pre-compression exhaust

[0152] The integrated slab is sent to a cold press for pre-pressing to remove gas from the slab and compact it to reduce the thickness of the slab;

[0153] (5) Hot pressing

[0154] The pre-pressed slab is sent to a hot press for hot pressing to produce a bamboo longitudinal and wood transverse composite integral container floor rough plate; the hot press is an intermittent single-layer hot press or an intermittent multi-layer hot press;

[0155] The hot pressing method is a "cold in - cold out" hot pressing molding process, specifically "feeding - heating - heat preservation and hot pressing - cooling - discharging" process;

[0156] The hot pressing process is divided into three stages: pressure increase, pressure holding, and unloading. During the pressure holding stage, the unit pressure of the hot press is 5.0 MPa and the temperature of the hot pressing plate is 150°C.

[0157] The thickness of the bamboo longitudinal and wood transverse composite container bottom plate is 40mm;

[0158] (6) Vertical and horizontal trimming

[0159] The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

[0160] Process Example 3

[0161] A bamboo longitudinal and wood transverse composite integral container bottom plate is prepared by the following steps:

[0162] (1) Material preparation process

[0163] Prepare radial bamboo curtains, and carry out glue dipping and drying to make longitudinal layer raw materials; prepare wood veneer, and carry out glue dipping and drying to make transverse layer raw materials;

[0164] (2) Slab paving

[0165] The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure;

[0166] Each layer of the horizontal layer of raw materials (wood veneer) is a single wood veneer, and each layer of the longitudinal layer of raw materials (radial bamboo curtains) is laid with a plurality of radial bamboo curtains, each bamboo curtain is horizontally butted, and no overlapping seams should appear on any vertical section of the slab; the width of the slab strip is the length of the wood veneer, and the length of the slab strip is 50m;

[0167] (3) Slab fixed length sawing

[0168] According to the width of the container bottom plate, the slab is cut into slabs of full length by band saw;

[0169] (4) Pre-compression exhaust

[0170] The integrated slab is sent to a cold press for pre-pressing to remove gas from the slab and compact it to reduce the thickness of the slab;

[0171] (5) Hot pressing

[0172] The pre-pressed slab is sent to a hot press for hot pressing to produce a bamboo longitudinal and wood transverse composite integral container floor rough plate; the hot press is an intermittent single-layer hot press or an intermittent multi-layer hot press;

[0173] The hot pressing method is a "cold in - cold out" hot pressing molding process, specifically "feeding - heating - heat preservation and hot pressing - cooling - discharging" process;

[0174] The hot pressing process is divided into three stages: pressure increase, pressure holding, and unloading. During the pressure holding stage, the unit pressure of the hot press is 8.0 MPa and the temperature of the hot pressing plate is 220°C.

[0175] The thickness of the bamboo longitudinal and wood transverse composite container bottom plate is 50mm;

[0176] (6) Vertical and horizontal trimming

[0177] The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

[0178] The following specific examples and comparative examples are all based on process example 2 (slab strip length 40m, hot pressing pressure 5.0MPa, hot pressing temperature 180°C, finished product thickness 40mm), and comparative tests were performed by adjusting the adhesive formulation.

[0179] Adhesive Example 1

[0180] Wood veneer adhesive: Lignin modified polyurethane adhesive

[0181] Preparation method:

[0182] Sodium lignin sulfonate was reacted with epichlorohydrin (1:0.5) at 70 °C for 3 h;

[0183] The prepolymer was mixed with MDI (1:2), 1% nano-silica dispersion (15% solid content) was added, and stirred at 60°C for 2 hours;

[0184] Viscosity: 1000~1500mPa·s

[0185] Curing conditions: 120℃ / 20min

[0186] Bamboo curtain adhesive: bamboo fiber reinforced soy protein adhesive

[0187] Preparation method:

[0188] Soy protein was mixed with deionized water (1:4), and 10% bamboo fiber nanocrystals (particle size 50 nm) were added, pH 10, and stirred at 60°C for 3 h;

[0189] Add 0.3% of the cross-linking agent genipin and continue stirring for 45 minutes;

[0190] Viscosity: 1500~2000mPa·s.

[0191] Curing conditions: 140℃ / 25min.

[0192] Adhesive Example 2

[0193] Only wood veneer glue modification

[0194] Wood veneer adhesive: the same lignin-modified polyurethane adhesive as in Adhesive Example 1.

[0195] Bamboo curtain adhesive: the same commercially available PF glue as in Comparative Example 1.

[0196] Adhesive Example 3

[0197] Wood veneer adhesive: the same commercially available MDI glue as in Comparative Example 2.

[0198] Bamboo curtain adhesive: the same as the bamboo fiber reinforced soybean protein adhesive in Adhesive Example 1.

[0199] Comparative Example 1 (Traditional Adhesive Combination)

[0200] Wood veneer adhesive: commercially available phenolic resin (PF) glue

[0201] Viscosity: 800~1500mPa·s

[0202] Curing conditions: 140℃ / 15min

[0203] Bamboo curtain adhesive: commercially available phenolic resin (PF) glue

[0204] Viscosity: 800~1500mPa·s

[0205] Curing conditions: 140℃ / 15min

[0206] Comparative Example 2

[0207] (Existing high performance adhesive combination)

[0208] Wood veneer adhesive: commercially available isocyanate glue (MDI)

[0209] Viscosity: 500-1000 mPa·s

[0210] Curing conditions: 120℃ / 20min

[0211] Bamboo curtain adhesive: commercially available isocyanate glue (MDI)

[0212] Viscosity: 500-1000 mPa·s

[0213] Curing conditions: 120℃ / 20min

[0214] Comparative Example 3

[0215] (Unmodified bio-based adhesive combination)

[0216] Wood veneer adhesive: Ordinary soy protein glue (without adding bamboo fiber nanocrystals)

[0217] Preparation method: Soy protein isolate and deionized water were mixed in a mass ratio of 1:4, pH 10, and stirred at 60°C for 2 hours.

[0218] Viscosity: 600-1200 mPa·s

[0219] Curing conditions: 150℃ / 30min

[0220] Bamboo curtain adhesive: ordinary soy protein glue (without adding bamboo fiber nanocrystals)

[0221] Same as wood veneer adhesive.

[0222] Test Example 1-1

[0223] Flexural strength (ASTM D3043)

[0224] Test Grouping

[0225] Adhesive Examples 1-3, Comparative Examples 1-3.

[0226] Test Method

[0227] Sample preparation: Take 5 finished bottom boards (size 250mm×50mm×40mm) for each group, and cut 3 specimens along the longitudinal direction (bamboo curtain direction) and the transverse direction (wood veneer direction).

[0228] Testing equipment: Universal material testing machine (accuracy ±1%).

[0229] Loading method: three-point bending method, span 200 mm, loading speed 5 mm / min, until the specimen breaks.

[0230] Data recorded: maximum load (N), mid-span deflection (mm), calculated bending strength (MPa).

[0231] Test standards

[0232] ASTM D3043: Test standard for flexural properties of unreinforced plastic lumber.

[0233] Bending strength formula:

[0234] F: maximum load, L: span, b: specimen width, h: specimen thickness.

[0235] Test data are shown in Table 3

[0236] Table 3 Bending strength test results

[0237] Group Longitudinal bending strength (MPa) Transverse bending strength (MPa) Comparative Example 1 85±3 30±2 Comparative Example 2 92±4 35±3 Comparative Example 3 78±2 25±1 Example 1 120±5 45±4 Example 2 105±4 38±3 Example 3 95±3 40±2

[0238] As can be seen in Table 3, Example 1 exhibits significantly better flexural strength than all comparative examples, with a 32% increase in longitudinal strength (vs. Comparative Example 2), demonstrating that the synergistic effect of lignin-modified polyurethane adhesive and bamboo fiber-reinforced soy protein adhesive effectively enhances interfacial bonding. Example 2 (modified only with the wood veneer adhesive) exhibits higher longitudinal strength than Comparative Example 2 (MDI adhesive), but lacks transverse strength, indicating that the unmodified bamboo curtain adhesive still presents weak points at the bamboo-wood interface. Comparative Example 3 (unmodified bio-based adhesive) exhibits the lowest strength, confirming that soy protein adhesive requires bamboo fiber nanocrystal reinforcement to meet performance requirements.

[0239] Test Example 1-2

[0240] Interlaminar shear strength (ISO 6238)

[0241] Test Grouping

[0242] Same as test example 1-1.

[0243] Test Method

[0244] 1. Sample preparation: Take 5 finished base plates from each group and cut them into 20mm×20mm×40mm specimens, ensuring that the interlayer interface is perpendicular to the loading direction.

[0245] 2. Testing equipment: universal material testing machine, loading speed 2mm / min.

[0246] 3. Data recording: maximum shear load (N), calculated interlaminar shear strength (MPa).

[0247] Test standards

[0248] ISO 6238: Test standard for shear strength of plywood.

[0249] The test data is shown in Table 4.

[0250] Table 4 Interlaminar shear strength test results

[0251] Group Interlaminar shear strength (MPa) Comparative Example 1 4.2±0.3 Comparative Example 2 5.0±0.4 Comparative Example 3 3.5±0.2 Example 1 7.8±0.5 Example 2 6.0±0.3 Example 3 5.5±0.4

[0252] As can be seen from Table 4, the interlaminar shear strength of Example 1 is increased by 56% compared with the commercially available MDI glue (Comparative Example 2), which is attributed to the shear resistance of the lignin polyurethane glue enhanced by nano-silica and the cross-linking effect of bamboo fiber nanocrystals and soy protein.

[0253] In Comparative Example 3, the adhesive was not modified, so the interfacial bonding force was insufficient and the strength was only 45% of that in Example 1.

[0254] Test Example 2

[0255] Strength retention rate after heat and humidity aging

[0256] Test Grouping

[0257] Same as test example 1-1.

[0258] Test Method

[0259] Aging conditions: 70°C, 85% relative humidity, for 168 hours.

[0260] Test content: Test the flexural strength and interlaminar shear strength after aging, and calculate the strength retention rate.

[0261] The test results are shown in Table 5.

[0262] Table 5 Strength retention rate after heat and humidity aging

[0263]

[0264]

[0265] As can be seen from the results in Table 5, Example 1 has the highest strength retention rate, indicating that the hydrolysis resistance of the lignin-modified polyurethane adhesive and the stability of the genipin-crosslinked soy protein adhesive are significantly superior to those of traditional adhesives. Comparative Example 1 (PF adhesive) has a strength retention rate of only 60-65% due to the insufficient moisture and heat resistance of the phenolic resin.

[0266] Test Example 3-1

[0267] Formaldehyde emission (GB / T 17657-2013)

[0268] Test Grouping

[0269] Comparative Example 1, Comparative Example 2, Example 1, Example 2, Example 3.

[0270] Test Method

[0271] 1. Test standard: Dessicator method (GB / T 17657-2013, 9-11L climate chamber method).

[0272] 2. Sample size: 150mm×50mm×40mm, 3 pieces per group.

[0273] 3. Data record: 24-hour formaldehyde release (mg / m 3 ).

[0274] The test data is shown in Table 6.

[0275] Table 6 Formaldehyde emission test results

[0276] Group <![CDATA[Formaldehyde emission (mg / m 3 )]]> Comparative Example 1 0.8±0.1 Comparative Example 2 0.3±0.05 Example 1 0.05±0.01 Example 2 0.4±0.08 Example 3 0.2±0.03

[0277] From the results in Table 6, it can be seen that the formaldehyde emission of Example 1 is close to zero (0.05 mg / m 3 ), because the adhesive is all bio-based and modified, no formaldehyde is added. Comparative Example 2 (MDI glue) releases trace formaldehyde (0.3mg / m 3 ), possibly from adhesive by-products.

[0278] Test Example 3-2

[0279] Biobased carbon content of adhesives (ASTM D6866)

[0280] Test Grouping

[0281] Comparative Example 1, Comparative Example 2, Example 1.

[0282] Test Method

[0283] Test standard: ASTM D6866 (Determination of biobased carbon content by radiocarbon analysis).

[0284] Sample processing: Take 5g of adhesive solid sample from each group, crush it and then test it.

[0285] The test data is shown in Table 7.

[0286] Table 7 Bio-based carbon content of adhesives

[0287] Group Bio-based carbon content (%) Comparative Example 1 20±2 Comparative Example 2 5±1 Example 1 85±3

[0288] Data Analysis

[0289] The bio-based carbon content of Example 1 reaches 85%, which is significantly higher than that of the traditional adhesive (Comparative Example 1 / 2), meeting the requirements of green manufacturing.

[0290] Application Example 1

[0291] Adhesive Example 1 is applied to the bottom plate of a standard shipping container

[0292] Application Scenario

[0293] Used in 40-foot standard dry cargo containers (inner dimensions 12.03m×2.35m), carrying cargo weight ≤ 28 tons, and exposed to high salt spray, humid and hot environments in the ocean for a long time.

[0294] Conditions of Use

[0295] Cyclic load: loading and unloading 2 times a day, peak dynamic load 30 tons

[0296] Environment: Humidity 70% to 95%, temperature -25℃ to 50℃

[0297] Service life requirement: ≥8 years

[0298] Performance

[0299] Mechanical properties:

[0300] Dynamic bending strength test (simulating forklift impact): 120MPa (longitudinal) remains stable with no visible cracks.

[0301] Salt spray test (ASTM B117, 1000h): interlaminar shear strength retention rate is 82%, which is better than traditional tropical hardwood flooring (usually <60%).

[0302] Economical:

[0303] Cost of single box bottom board: traditional tropical hardwood splicing board is about ￥12,000, the whole bottom board of this invention

[0304] ￥9,500, a 21% cost reduction.

[0305] Maintenance cycle: Traditional baseboards require replacement of joint reinforcements every three years, while the present invention requires no maintenance, reducing the cost over the entire life cycle by 35%.

[0306] Advantage Analysis

[0307] The integrated structure avoids seam corrosion, and combined with bamboo's natural mildew resistance, it meets the harsh environmental requirements of maritime transport.

[0308] Bio-based adhesives are resistant to salt spray penetration and can reduce salt spray corrosion area by 90% compared to MDI adhesive substrates.

[0309] Application Example 2

[0310] Adhesive Example 1 is applied to the bottom plate of a recyclable environmentally friendly container house

[0311] Application Scenario

[0312] For modular container houses, the bottom plate must be removable and reassembled ≥5 times and biodegradable after being scrapped.

[0313] Conditions of Use

[0314] Assembly and disassembly cycle: hydraulic clamp fixation / release, cycle load 10 times

[0315] Recycling requirements: Material biodegradation rate ≥ 70% (180 days composting)

[0316] Performance

[0317] Reusability:

[0318] After 10 times of disassembly and assembly, the bending strength retention rate is 92% and the screw holding force decreases by ≤8%.

[0319] Compared with the traditional OSB board: the edge of the OSB board cracked after being disassembled and assembled three times, while the present invention had no structural damage.

[0320] Degradability:

[0321] 180-day soil burial experiment: The degradation rate of bamboo substrate is 75%, and the degradation rate of adhesive layer is 60% (the degradation rate of traditional PF adhesive is <5%).

[0322] Advantage Analysis

[0323] Bio-based adhesives (soy protein + lignin) can be decomposed by microorganisms, and the recycling rate of the entire board reaches 85%.

[0324] The natural fiber structure of bamboo can still maintain soil permeability after degradation, which meets the requirements of the circular economy.

[0325] In summary, it can be seen from the above embodiments and test examples that:

[0326] Example 1 (fully modified adhesive) has the best overall performance:

[0327] Flexural strength 120MPa (longitudinal), interlaminar shear strength 7.8MPa;

[0328] The strength retention rate after heat and humidity aging is 90%;

[0329] Formaldehyde emissions are close to zero and bio-based carbon accounts for 85%.

[0330] Comparative Example 2 (MDI glue) has suboptimal mechanical properties but poor environmental performance;

[0331] Examples 2-3 partially improved performance, but failed to achieve coordinated optimization of the entire system.

[0332] The above data fully verify the significant advantages of the adhesive system of the present invention in mechanical properties, environmental adaptability and environmental protection, and meet the needs of industrial production of container bottom plates.

[0333] The above are only a few preferred embodiments of the present invention, and their description is relatively specific and detailed, but it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and such modifications and improvements are within the scope of protection of the present invention.

Claims

1. A bamboo longitudinal and wood transverse composite container floor, characterized by: Prepared by the following steps: (1) Material preparation process Prepare radial bamboo curtains, and carry out glue dipping and drying to make longitudinal layer raw materials; prepare wood veneer, and carry out glue dipping and drying to make transverse layer raw materials; (2) Slab paving The wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, wood veneer, radial bamboo curtain, and wood veneer are continuously laid from bottom to top to form a slab strip of any length with a seven-layer structure; Each layer of the horizontal layer of raw materials is a wooden veneer, and each layer of the longitudinal layer of raw materials is laid with a number of radial bamboo curtains, each bamboo curtain is horizontally butted and spliced, and no overlapping seams should appear on any vertical section of the slab; the width of the slab strip is the length of the wooden veneer, and the length of the slab strip is 30 to 50 meters; (3) Slab fixed length sawing According to the width of the container bottom plate, the slab is cut into slabs of full length by band saw; (4) Pre-compression exhaust The integrated slab is sent to a cold press for pre-pressing to remove gas from the slab and compact it to reduce the thickness of the slab; (5) Hot pressing The pre-pressed slab is sent to a hot press for hot pressing to produce a bamboo longitudinal and wood transverse composite whole container floor rough board; The thickness of the bamboo longitudinal and wood transverse composite container bottom plate is 20 to 50 mm. (6) Vertical and horizontal trimming The heat-pressed bamboo longitudinal and transverse composite integral container bottom plate is trimmed to form a standardized bamboo longitudinal and transverse composite integral container bottom plate.

2. The bamboo longitudinal and wood transverse composite container floor according to claim 1 is characterized by: In step (1), the radial bamboo curtain and the wood veneer are subjected to a dipping treatment; the mass ratio of the dipping amount: the adhesive solid amount to the absolute dry wood veneer amount / the absolute dry bamboo curtain amount is (3-12):

100.

3. The bamboo longitudinal and wood transverse composite container floor according to claim 2 is characterized in that: In step (5), the hot press is an intermittent single-layer hot press or an intermittent multi-layer hot press; The hot pressing method is a "cold in - cold out" hot pressing molding process, specifically the process of feeding - heating - heat preservation and hot pressing - cooling - discharging; The hot pressing process is divided into three stages: pressure increase, pressure holding, and unloading. During the pressure holding stage, the unit pressure of the hot press is 1.5~8.0MPa, and the temperature of the hot pressing plate is 140~220℃.

4. The bamboo longitudinal and wood transverse composite container floor according to claim 1 is characterized by: In step (1), the method for preparing the wood veneer is: Saw the logs into the length of the wood veneer, process them into veneer strips through a peeling machine, or splice them into longer veneer strips through a veneer shearing machine and a splicing machine; dip the veneer strips into glue; and place the dipped veneer strips in a dryer for drying; Specific process parameters: Veneer strip width: the length of the wood veneer; veneer strip length: 30~50m; Glue impregnation amount: The mass ratio of adhesive solids to absolute dry wood veneer is (3-12):100; The moisture content of wood veneer after drying is 2% to 8%.

5. The bamboo longitudinal and wood transverse composite container floor according to claim 4 is characterized in that: The adhesive of the wood veneer is a lignin-modified polyurethane adhesive, and its preparation method comprises the following steps: (1) mixing sodium lignin sulfonate and epichlorohydrin in a mass ratio of 1:(0.3-0.8), reacting at 60-80° C. for 2-4 hours to generate a lignin-based epoxy prepolymer; (2) mixing the prepolymer and polyisocyanate MDI in a mass ratio of 1:(1.5-2.5), adding 0.5%-2% of a nano-silicon dioxide dispersion, and stirring at 50-70° C. for 1-3 hours to prepare a lignin-modified polyurethane adhesive; The adhesive has a viscosity of 500 to 1500 mPa·s, a curing temperature of 100 to 140° C., and a curing time of 10 to 30 minutes.

6. The bamboo longitudinal and wood transverse composite container floor according to claim 5, characterized in that: The particle size of the nano silicon dioxide dispersion is 10-50 nm, and the silicon dioxide content in the dispersion is 10%-20%.

7. The bamboo longitudinal and wood transverse composite container floor according to claim 1 is characterized by: In step (1), the preparation method of the radial bamboo curtain is: The original bamboo segment is split into arc-shaped bamboo blanks, which are then split into radial strips by a radial strip splitting machine, and the radial strips are woven into a bamboo curtain of continuous length by a bamboo curtain weaving machine; the bamboo curtain is then placed in a glue dipping tank for dipping; and the glued bamboo curtain is placed in a dryer for drying; Specific process parameters: The width of the radial bamboo curtain is the natural length of the bamboo strips; the length of the radial bamboo curtain is 30 to 50 meters; Glue impregnation amount: the mass ratio of adhesive solid amount to dry bamboo curtain amount is (3-12):100; The moisture content of bamboo curtain after drying: 2%~8%.

8. The bamboo longitudinal and wood transverse composite container floor according to claim 7, characterized in that: The adhesive of the radial bamboo curtain is bamboo fiber reinforced soybean protein adhesive, and its preparation method comprises the following steps: (1) Soy protein isolate and deionized water are mixed in a mass ratio of 1:(3-5), bamboo fiber nanocrystals accounting for 5%-15% of the weight of the soy protein are added, and the mixture is stirred at a pH of 9-11 and a temperature of 50-70° C. for 2-4 hours to form a homogeneous gel; (2) adding genipin, a cross-linking agent, at a concentration of 0.1% to 0.5% by weight of the total glue solution, and continuing stirring for 30 to 60 minutes; The adhesive has a viscosity of 800 to 2000 mPa·s, a curing temperature of 120 to 160° C., and a curing time of 15 to 40 minutes.

9. The bamboo longitudinal and wood transverse composite container floor according to claim 8, characterized in that: The preparation method of the bamboo fiber nanocrystals is: (1) The bamboo fiber is hydrolyzed with sulfuric acid (concentration 60% to 70%, temperature 50 to 70°C) for 2 to 4 hours; (2) After centrifugal washing to neutrality, the mixture was ultrasonically dispersed in deionized water to obtain a bamboo fiber nanocrystal suspension with a particle size of 20 to 100 nm.

10. Use of the bamboo longitudinal and wood transverse composite integrated container bottom plate according to any one of claims 1 to 9 in preparing container bottom plates.

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