Assembling process and production method of bamboo chip tray

Abstract

The invention discloses an assembling process and a production method of a bamboo chip tray, and relates to the technical field of bamboo wood processing. The process comprises the steps of bamboo chip preparation (cutting, green and yellow removal and chamfering and polishing), bamboo chip treatment (drying or nitrogen protection carbonization), connection and fixation (code nail, straight nail and screw synergistic reinforcement) and structure optimization (double-layer cross lamination and metal reinforcing plate pre-embedding). According to the production method, the quality is ensured through X-ray flaw detection and dynamic load testing. The bamboo chip tray has the high-strength characteristic that the static bearing capacity is larger than or equal to 2000 kg, and the dynamic bearing capacity is larger than or equal to 800 kg, and due to the 0.1-0.3 mm compact layer formed through nitrogen carbonization, the mildew-proof grade of the bamboo chip tray reaches the GB / T 18261-2013 II grade. By adopting the bamboo-plastic composite material, the plastic consumption can be reduced by 30%, the production period is shortened by 50%, and the yield is greater than or equal to 95%. The modular design is suitable for multi-scene application of industrial logistics, cold-chain transportation and the like, and the maintenance cost is reduced by 40%. The problems that a traditional bamboo tray is low in strength, prone to mildew and the like are solved, and the bamboo tray is environmentally friendly and economical.

Description

Technical Field

[0001] The present invention relates to the technical field of bamboo processing, and specifically to an assembly process and production method of a bamboo sheet pallet. Background Art

[0002] With the improvement of global environmental awareness and the promotion of the "bamboo replacing plastic" policy, bamboo, as a renewable and degradable green material, has seen a significant increase in application demand in fields such as packaging and logistics. However, traditional bamboo pallets still have technical bottlenecks in production processes, structural strength, and mildew prevention performance, which limit their large-scale industrial application. The following are the main limitations of the existing technology and industry requirements:

[0003] 1. Insufficient bamboo processing technology

[0004] In traditional bamboo processing techniques, bamboo slices are prone to deformation and cracking due to uneven drying (large moisture content fluctuations), and there is a lack of standardized control in the processes of removing the green layer and yellow layer, which affects the mechanical properties of the middle dense layer of bamboo. For example, ordinary drying processes (60 - 80°C) are difficult to completely remove sugars and starches in bamboo, resulting in a mildew prevention level only reaching the basic standard (such as the primary requirements of ASTM D2017), and unable to meet the long-term use requirements in high-humidity environments.

[0005] 2. Defects in structural stability

[0006] Existing bamboo pallets mostly use single-layer bamboo slice splicing or simple bonding processes, with problems such as low load-bearing capacity (static load usually ≤ 1500 kg) and easy loosening of joints. Some enterprises have tried to introduce metal reinforcement parts, but there is a lack of systematic structural optimization (such as large deviations in lamination angles and insufficient thickness of reinforcement plates), resulting in excessive deformation during dynamic load testing (the ISO8611 standard requires the deformation amount ≤ 3 mm).

[0007] 3. Limitations in mildew and insect prevention technology

[0008] Conventional carbonization processes mostly use high-temperature steam treatment, but do not introduce protective gases (such as nitrogen), resulting in uneven carbonized layers on the surface of bamboo (thickness < 0.1 mm), and the mildew prevention level only meets the requirements of Grade I in the GB / T 18261 - 2013 standard. In addition, the end faces of bamboo slices are not treated with epoxy resin penetration, which is prone to microcracks and accelerates the growth of mildew.

[0009] 4. Shortcomings in production efficiency and quality control

[0010] Traditional assembly processes rely on manual fixation (such as ordinary nailing), without combining the collaborative application of multiple types of fasteners (staple nails, straight nails, screws), resulting in a long production cycle and poor consistency. At the same time, the quality inspection methods are single (such as visual inspection), making it difficult to detect internal connection defects (such as offset screw holes or gluing bubbles), which affects the qualified rate of finished products.

[0011] 5. Dilemma of Balancing Environmental Friendliness and Cost

[0012] Although early bamboo-plastic composites could enhance strength, they relied on polyolefin substrates (accounting for 40%-60%), which was contrary to the "fully bamboo" environmental protection goal and had a relatively high raw material cost. In addition, traditional sealing treatments used non-environmental adhesives and were difficult to meet the low VOC emission requirements of UV-curable sealants.

[0013] In response to the above problems, the industry urgently needs to develop an assembly process and production method for bamboo sheet pallets. Summary of the Invention

[0014] The technical problems to be solved by the present invention are the deficiencies in bamboo processing technology, the defects in structural stability, the limitations in mold and insect prevention technology, the shortfalls in production efficiency and quality control, and the dilemma of balancing environmental friendliness and cost.

[0015] The technical solution adopted by the present invention is: an assembly process for bamboo sheet pallets, comprising the following steps:

[0016] S1. Bamboo Sheet Preparation:

[0017] Cut the raw bamboo into bamboo sheets with a length of 500 mm to 1200 mm, a width of 30 mm to 80 mm, and a thickness of 8 mm to 15 mm;

[0018] Debark and debamboo-yellow the bamboo sheets, retain the dense layer in the middle of the bamboo, and chamfer and polish the four sides, with a chamfer radius of 0.5 mm to 1 mm;

[0019] S2. Bamboo Sheet Treatment:

[0020] Drying Treatment: Place the bamboo sheets in a drying kiln and dry them at 60°C to 80°C for 24 to 48 hours to reduce the moisture content to 8% to 12%;

[0021] S3. Connection and Fixation:

[0022] Nail Fixation: Use 25 mm to 45 mm stainless steel nails to preliminarily fix the joints of the bamboo sheets, and the spacing of the stainless steel nails is 50 mm to 80 mm;

[0023] Straight Nail Reinforcement: Use 30 mm to 50 mm galvanized straight nails to enhance the structural stability. The galvanized straight nails and the nails are staggered, with an included angle of 45° to 90°;

[0024] Screw Locking: Use hardware screws and lock nuts to lock at the load-bearing nodes (such as pallet foot stools and frame connections). The length of the hardware screws is 45 mm to 110 mm, and bamboo anti-cracking glue is pre-coated in the screw holes, and its curing time ≥ 30 minutes.

[0025] As a further solution of the present invention: The drying treatment may be carbonization treatment: Put the bamboo slices into a steam carbonization furnace and carbonize them for 2.5 to 3.5 hours under the conditions of 130°C ± 5°C and 0.35 MPa to 0.45 MPa. After carbonization, dry them again until the moisture content ≤ 10%.

[0026] As a further solution of the present invention: In the carbonization treatment process, introduce nitrogen with a purity ≥ 99.5% into the carbonization furnace as a protective gas. After carbonization, a dense carbonized layer with a thickness of 0.1 mm to 0.3 mm is formed on the surface of the bamboo slices, and its mold-proof grade reaches the requirements of the ASTM D2017 standard.

[0027] As a further solution of the present invention: The bamboo slices need to be subjected to anti-cracking treatment before assembly: Coat the end faces of the bamboo slices with an epoxy resin penetrant with a viscosity of 200 to 300 cP and cure it at 40°C to 50°C for 1 to 2 hours.

[0028] A production method of a bamboo slice pallet includes the following steps:

[0029] S1. Structure optimization:

[0030] The bottom of the pallet is laminated with double-layer bamboo slices in a cross pattern, with an interlayer angle of 90° ± 5°, and the layers are bonded with a polyurethane adhesive with a coating amount of 80 to 120 g / m 2 ;

[0031] Embed metal reinforcement plates at the four corners and the load-bearing beam positions of the pallet. The reinforcement plates are galvanized steel plates with a thickness of 2 mm to 3 mm and are fixed through screws.

[0032] S2. Quality inspection:

[0033] Use an X-ray flaw detector to scan the internal defects of the screw connection nodes, with a detection accuracy of 0.1 mm;

[0034] Conduct a dynamic load test on the finished pallet. According to the ISO8611 standard, the deformation amount ≤ 3 mm after loading 1.5 times the rated weight.

[0035] As a further solution of the present invention: The connection part of the screw needs to be sealed: Install a rubber washer on the screw head and cover it with a UV-curable sealant with a thickness of 0.5 mm to 1 mm.

[0036] A bamboo slice pallet, the structural composition:

[0037] The pallet panel is assembled by carbonized bamboo slices, with a splicing gap ≤ 1 mm, and the surface roughness Ra of the panel ≤ 3.2 μm;

[0038] The bottom support structure adopts a "well"-shaped reinforcing rib, with a height of the reinforcing rib of 30 mm to 50 mm and a width of 20 mm to 40 mm;

[0039] Performance indicators:

[0040] The mildew and moth-proof performance meets the requirements of GB / T18261-2013 standard level II;

[0041] Static load ≥ 2000kg, dynamic load ≥ 800kg, according to ISTA3E test standard.

[0042] Beneficial effects of the present invention:

[0043] 1. Significant improvement in structural performance

[0044] Through the process of removing green and yellow from bamboo pieces, chamfering and polishing the four sides, and multi-layer cross-lamination (90°±5°), combined with the pre-embedded metal reinforcement plate (galvanized steel plate thickness 2-3mm) and the coordinated fixation of various types of fasteners (stainless steel nails, galvanized straight nails, anti-loosening screws), the static load capacity of bamboo pallets is ≥2000kg, the dynamic load capacity is ≥800kg, and the deformation is ≤3mm (ISO8611 standard). The 0.1-0.3mm dense carbonized layer formed by carbonization treatment (130℃±5℃, nitrogen protection) further enhances the mildew and moth resistance performance, meeting the requirements of ASTMD2017 and GB / T18261-2013 standard level II.

[0045] 2. Outstanding environmental advantages

[0046] The use of all bamboo or bamboo-plastic composite materials (40% bamboo fiber addition) can reduce the use of plastic by more than 30%. The bamboo growth cycle is short (3-5 years to mature), and the carbon sequestration efficiency is three times that of wood. In the production process, bamboo scraps (cost only 200 yuan / ton) and recycled plastics (2,000 yuan / ton) are used to realize waste resource utilization. The molding process does not discharge wastewater, and VOC gases are centrally treated and discharged in compliance with the "dual carbon" goal. The pallet is completely biodegradable, avoiding traditional plastic pollution.

[0047] 3. Cost and production efficiency optimization

[0048] Standardized bamboo processing (dimensional tolerance ±0.5mm) combined with automated equipment (such as 1000-ton hydraulic molding press) shortens the production cycle by 50% and increases the yield rate to more than 95%. Anti-cracking treatment (curing with epoxy resin penetrant) reduces the bamboo chip loss rate by about 20%, while the nitrogen protection carbonization process extends the mildew-proof life of bamboo to more than 10 years, reducing maintenance costs. The unit cost of bamboo plastic pallets is 15%-20% lower than that of pure plastic, with significant cost-effectiveness advantages.

[0049] 4. Enhanced functionality and scene adaptability

[0050] The surface roughness Ra of the tray panel is ≤ 3.2 μm. With the cooperation of a rope knot protection net (flat hole bundling design) and a rubber gasket for sealing, it can adapt to high-humidity environments such as cold chain and fresh food, and the anti-slip performance is improved by 30%. The modular assembly design supports the quick replacement of damaged components (such as the screw connection of the foot pier), the maintenance cost is reduced by 40%, and the whole-life cycle quality monitoring can be achieved through X-ray flaw detection (accuracy 0.1 mm).

[0051] 5. Policy and Market Competitiveness Enhancement

[0052] Relying on the national "bamboo replacing plastic" policy (such as the "Implementation Guide for Green Manufacturing Projects") and FSC forest certification, the bamboo chip tray has obtained the qualification for access to the international supply chain, and the premium space for exporting to the European and American markets reaches 20% - 30%. Specific Implementation Modes

[0053] The present invention will be further described below.

[0054] Example 1: Traditional All-Bamboo Structure Tray (Comparative Example)

[0055] Process Characteristics: The whole bamboo is cut, de-inked and de-yellowed, and then directly assembled, fixed with bamboo nails or rattan, and there is no metal reinforcement.

[0056] Performance Indicators: Static load-bearing ≤ 800 kg, dynamic load-bearing ≤ 300 kg, deformation ≥ 8 mm (ISO8611 test); the mildew-proof grade only reaches Grade I of the GB / T18261 - 2013 standard.

[0057] Defects: The bamboo material is not carbonized, so it is easy to mildew and crack; the node fixation depends on manual work, and the stability is poor; the gap between bamboo chips ≥ 3 mm, and the surface roughness Ra ≥ 6.3 μm.

[0058] Example 2: Bamboo-Plastic Composite Tray (Main Example)

[0059] Process Innovations:

[0060] 1. Bamboo fiber (40%) and recycled plastic (60%) are kneaded and molded by compression molding, using a 90° cross-laminating process.

[0061] 2. Galvanized steel plates (2 - 3 mm) are pre-embedded in the tray foot pier, and reinforced with anti-loosening screws + UV sealant.

[0062] Performance Improvements:

[0063] 1. Strength: Static load-bearing ≥ 2000 kg (+150%), dynamic load-bearing ≥ 800 kg (+166%), deformation ≤ 2.5 mm.

[0064] 2. Environmental friendliness: The raw material cost of bamboo fiber is only 200 yuan per ton, and the recycling plastic utilization rate reaches 100%; there is no wastewater discharge in the molding process, and the VOC emission is reduced by 30%.

[0065] 3. Mildew resistance: A 0.2-mm dense layer is formed by carbonization under nitrogen protection, and the mildew resistance level reaches Grade II of the ASTM D2017 standard.

[0066] Example 3: Modular lightweight pallet (optimized example)

[0067] Structural design:

[0068] The panel is made of double-layer bamboo slices + polyurethane adhesive (coating amount 100 g / m 2 ) and cross-laminated with an interlayer angle of 85° to 95°.

[0069] The foot pier is a hollow bamboo-plastic structure with a honeycomb aluminum core embedded, and the self-weight is reduced by 40% (from 18 kg per single pallet to 10.8 kg).

[0070] Function expansion:

[0071] Flat hole bundling positions are set on the four sides of the panel, which are compatible with rope knot protection nets (hole diameter 0.2 - 0.5 cm) to meet the anti-slip requirements of the cold chain.

[0072] The foot pier can be quickly replaced, and the maintenance cost is reduced by 50%.

[0073] Example 4: Multifunctional home improvement pallet (expanded example)

[0074] Innovation points:

[0075] A card slot (length 10 - 15 cm × width 3 - 6 cm) is set in the left half area of the panel, and tea cups / dish drainers can be vertically inserted.

[0076] A water guide hopper (tilt angle 5°) + a bamboo strip solid-liquid separation net (hole diameter 0.3 cm) are integrated at the bottom to achieve oil-water separation.

[0077] Applicable scenarios: Catering back kitchens, home storage, but the industrial load-bearing performance is weak (static load ≤ 500 kg).

[0078] Example comparison and analysis table:

[0079]

[0080] Technical route selection suggestions

[0081] 1. In the field of industrial logistics: It is preferred to choose Example 2 (bamboo-plastic composite), which has significant comprehensive strength and cost advantages and is suitable for scenarios such as shipping containers and automated stereoscopic warehouses.

[0082] 2. Cold chain light load scenario: Example 3 (lightweight modular) has strong adaptability. The honeycomb aluminum core structure can resist low-temperature deformation at -20°C, and the anti-slip performance is improved by 30%.

[0083] 3. Environmentally friendly policy-oriented area: Example 4 (home decoration type) conforms to the policy subsidy direction of "replacing plastic with bamboo", but it needs to be supported by FSC certification of bamboo to expand the international market.

[0084] Through the comparison of multiple examples, it can be seen that the bamboo-plastic composite pallet achieves the optimal balance between strength and environmental protection, and the modular design represents the future lightweight trend. The two work together to cover 90% of the industrial scenario requirements.

[0085] The above examples are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An assembly process of a bamboo tray, characterized in that, It includes the following steps: S1. Bamboo slice preparation: Cut the raw bamboo into bamboo slices with a length of 500 mm to 1200 mm, a width of 30 mm to 80 mm, and a thickness of 8 mm to 15 mm; Debark and de-yellow the bamboo slices, retain the dense middle layer of the bamboo material, and chamfer and polish the four sides, with a chamfer radius of 0.5 mm to 1 mm; S2. Bamboo slice treatment: Drying treatment: Place the bamboo slices in a drying kiln and dry them at 60°C to 80°C for 24 to 48 hours to reduce the moisture content to 8% to 12%; S3. Connection and fixation: Nail fixation: Use 25 mm to 45 mm stainless steel nails to preliminarily fix the joints of the bamboo slices, and the spacing of the stainless steel nails is 50 mm to 80 mm; Straight nail reinforcement: Use 30 mm to 50 mm galvanized straight nails to enhance the structural stability. The galvanized straight nails and the nails are staggered, with an included angle of 45° to 90°; Screw locking: Use hardware screws with locknuts to lock at the load-bearing joints. The length of the hardware screws is 45 mm to 110 mm, and bamboo anti-cracking glue is pre-coated in the screw holes, and its curing time ≥ 30 minutes.

2. The assembly process of a bamboo tray according to claim 1, characterized in that: The optional carbonization treatment for the drying treatment: Put the bamboo slices into a steam carbonization furnace and carbonize them at 130°C ± 5°C and 0.35 MPa to 0.45 MPa for 2.5 to 3.5 hours. After carbonization, dry them again until the moisture content ≤ 10%.

3. The assembly process of a bamboo sheet tray according to claim 2, characterized in that: In the carbonization treatment process, introduce nitrogen with a purity ≥ 99.5% into the carbonization furnace as a protective gas. A dense carbonized layer of 0.1 mm to 0.3 mm is formed on the surface of the carbonized bamboo slices, and its mildew-proof grade meets the requirements of ASTM D2017 standard.

4. The assembly process of a bamboo sheet tray according to claim 1, characterized in that: The bamboo slices need to be treated against cracking before assembly: Coat the end faces of the bamboo slices with an epoxy resin penetrant with a viscosity of 200 to 300 cP and cure it at 40°C to 50°C for 1 to 2 hours.

5. A production method of a bamboo chip tray, characterized in that, It includes the following steps: S1. Structure optimization: The bottom of the tray is made of double-layer bamboo slices laminated crosswise, with an included angle of 90° ± 5° between layers, and the layers are bonded with polyurethane adhesive, with a coating amount of 80 - 120 g / m 2 ; Embed metal reinforcement plates at the four corners and the load-bearing beam positions of the tray. The reinforcement plates are galvanized steel plates with a thickness of 2 mm to 3 mm and are fixed through screws; S2. Quality inspection: Use an X-ray flaw detector to scan the internal defects of the screw connection joints, and the detection accuracy is 0.1 mm; Conduct a dynamic load test on the finished tray. According to the ISO 8611 standard, the deformation amount ≤ 3 mm after loading 1.5 times the rated weight.

6. The production method of a bamboo chip tray according to claim 5, characterized in that: The connection part of the screw needs to be sealed: Install a rubber washer on the screw head and cover it with a UV-curable sealant with a thickness of 0.5 mm to 1 mm.

7. A bamboo slice tray, characterized in that: Structural composition: The tray panel is assembled by carbonized bamboo slices, the splicing gap ≤ 1 mm, and the surface roughness Ra of the panel ≤ 3.2 μm; The bottom support structure adopts a "well"-shaped reinforcing rib, and the height of the reinforcing rib is 30 mm to 50 mm, and the width is 20 mm to 40 mm; Performance indicators: The mildew-proof and moth-proof performance meets the requirements of Grade II of the GB / T 18261-2013 standard; The static load-bearing ≥ 2000 kg, and the dynamic load-bearing ≥ 800 kg, according to the ISTA3E test standard.

Images