Nail-free recyclable fumigation-free wooden tray and preparation method thereof

Abstract

The invention provides a nail-free recyclable fumigation-free wooden tray and a preparation method thereof, and belongs to the technical field of tray production and processing. The nail-free recyclable fumigation-free wooden tray comprises the longitudinal beams, the cushion blocks and the bed boards, the longitudinal beams and the cushion blocks are bonded through high-strength woodworking glue, the cushion blocks and the bed boards are bonded through high-strength woodworking glue, nails are completely avoided, and therefore recycling and reprocessing are facilitated. The high-strength and high-water-resistance OSB board prepared by a 190-240 DEG C four-stage hot press molding process is used as a wood material of the tray, and is further matched with high-strength woodworking glue of a specific formula, so that the prepared wood tray meets the general technical requirements of GB / T 31148-2022-wood flat trays on the premise of meeting the IPPC fumigation-free standard of European Union.

Description

Technical Field

[0001] This invention relates to the field of pallet manufacturing and processing technology, specifically to a nail-free, recyclable, fumigation-free wooden pallet and its preparation method. Background Technology

[0002] Wooden pallets are made from natural wood, engineered wood, and other wood-based materials. Currently, the main materials used for natural wood pallets in China include pine, mixed hardwoods, and other hardwoods. Natural wood pallets require heat treatment or methyl bromide fumigation to meet EU IPPC standards. Engineered wood pallets are fumigation-free and are primarily made from plywood, high-density fiberboard (HDF), and OSB (Oriented Strand Board). HDF is susceptible to moisture damage and swelling, has poor nail-holding power, and lacks structural strength. Plywood offers balanced performance but is more expensive. OSB offers higher performance than HDF and is cheaper than plywood; therefore, using OSB for pallets ensures both performance and cost-effectiveness. However, existing OSB technology also suffers from low internal bond strength and poor water resistance in conventional products.

[0003] Currently, there are various types of nail-free pallets on the market, as well as numerous patents for nail-free wooden pallets. For example, CN202022558544.3 and CN202422402223.2 both disclose "a nail-free assembled wooden pallet," whose main feature is the ability to assemble the wooden pallet without nails through connecting clips. However, pallets connected mechanically have low structural stability and limited service life.

[0004] To address the aforementioned problems, this invention provides a nail-free, recyclable, and fumigation-free wooden pallet. Its base is made of high-strength, highly water-resistant OSB board, and the connections between various components are made of high-strength wood glue. The resulting wooden pallet is both nail-free and fumigation-free, and meets the requirements of GB / T 31148-2022 - General Technology for Wooden Flat Pallets. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a nail-free, recyclable, fumigation-free wooden pallet and its preparation method. The invention first uses a specific wood glue formula and a four-stage hot-pressing process to prepare a high-strength, high-water-resistant OSB board. Then, using the high-strength, high-water-resistant OSB board as the wood substrate, high-strength wood glue formulated with a specific ratio of EVCL emulsion and VAE emulsion is used to bond the various components, resulting in a completely nail-free, recyclable, fumigation-free wooden pallet with higher strength and better handling.

[0006] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0007] This invention provides a nail-free, recyclable, and fumigation-free wooden pallet, comprising longitudinal beams, pad blocks, and flooring. The longitudinal beams and pad blocks, and the pad blocks and flooring are bonded together with high-strength wood adhesive. The high-strength wood adhesive is a two-component formulation system, with component A being a water-based adhesive and component B being a curing agent. The formulation of component A is as follows:

[0008] Ethylene-vinyl chloride copolymer emulsion (EVCL emulsion): 25-35 parts;

[0009] Ethylene-vinyl acetate copolymer emulsion (VAE emulsion): 10-20 parts;

[0010] Plasticizer: 1.0-3.0 parts;

[0011] Wetting agent: 0.1-0.5 parts;

[0012] Calcium carbonate: 20-30 parts;

[0013] Defoamer: 0.1-0.3 parts;

[0014] Fungicide: 0.1-0.3 parts.

[0015] Furthermore, the solid content of the ethylene-vinyl chloride copolymer emulsion is 40%-60%, and the solid content of the ethylene-vinyl acetate copolymer emulsion is 40%-60%.

[0016] Furthermore, the mass ratio of component A to component B is 100:(15-20).

[0017] Furthermore, component B is MDI (diphenylmethane diisocyanate).

[0018] Furthermore, the bonding between the longitudinal beam and the pad, and between the pad and the slab, is achieved by applying adhesive using a brushing process, with an adhesive application rate of 150±50 g / m. 2 .

[0019] Furthermore, the wood material of the nail-free, recyclable, fumigation-free wooden pallet is OSB board, that is, the longitudinal beams, pads and flooring are made of OSB board.

[0020] Furthermore, the entire OSB board is pre-bonded to the required thickness, with an adhesive application rate of 150±50 g / m². 2 After the glue has cured, it is cut into pads.

[0021] Furthermore, the OSB board has the following formulation:

[0022] Surface layer: Wood shavings 192 kg / m² 3 MDI 6.5-10.0 kg / m³ 3 EVCL emulsion 2.0-7.0 kg / m³ 3Emulsified paraffin wax 3-8 kg / m 3 ;

[0023] Core layer: 375 kg / m³ wood shavings 3 MDI 8.5-15.0 kg / m³ 3 EVCL emulsion 3.0-8.0 kg / m 3 2-5 kg / m³ of molten paraffin 3 .

[0024] Furthermore, the solid content of the emulsified paraffin is 30%-50%.

[0025] Furthermore, the manufacturing process of the OSB board is as follows:

[0026] After mixing the adhesive and laying it, a four-stage hot pressing process is carried out.

[0027] The hot pressing factor during the four-stage hot pressing process is 8-12 s / mm;

[0028] The temperatures for the four-stage hot pressing process are as follows: 230-240℃ (stage 1), 225-235℃ (stage 2), 215-225℃ (stage 3), and 190-195℃ (stage 4).

[0029] The thickness of the prepared OSB board is 14-20 mm.

[0030] Furthermore, the plasticizer includes, but is not limited to, at least one of dioctyl phthalate (DOP / DEHP), dibutyl phthalate (DBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dioctyl adipate (DOA), dioctyl sebacate (DOS), dioctyl azelate (DOZ), tricresyl phosphate (TCP), triphenyl phosphate (TPP), and trioctyl phosphate (TOP).

[0031] Furthermore, the wetting agent includes, but is not limited to, at least one of alkylphenol polyoxyethylene ether (APEO), polyether ether ketone (PEEK), polyimide (PI), organically modified polysiloxane, phosphate ester, and methyl carboxylate.

[0032] Furthermore, the calcium carbonate has a particle size of 300-800 mesh.

[0033] Furthermore, the defoamer includes, but is not limited to, at least one of polydimethylsiloxane, polyether-modified polysiloxane, glycerol polyoxypropylene ether, polyoxyethylene polyoxypropylene glycerol ether, polyoxyethylene polyoxypropylene propylene glycol ether, vinyl bis-stearamide, and sorbitan monooleate.

[0034] Furthermore, the bactericide includes, but is not limited to, at least one of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 3-iodo-2-propynyl butylcarbamate, 2,2-dibromo-3-azolidinamide, and 2-mercaptobenzothiazole sodium salt.

[0035] This invention also provides a method for preparing the nail-free, recyclable, fumigation-free wooden pallet, comprising the following steps:

[0036] Formulate wood glue for nail-free bonding;

[0037] OSB boards are cut to size for use in fabricating flooring and longitudinal beams;

[0038] OSB boards are bonded to the required thickness using high-strength wood glue. The glue is applied by brushing, scraping, or rolling. Once dry, the boards are stacked and fixed by their own weight; no pressure is required. The glue application rate is 150±50 g / m². 2 After the glue has cured, cut it into pads;

[0039] The pallet boards, pads, and longitudinal beams are bonded together according to the required dimensions. Adhesive is applied by brushing, scraping, or rolling. Once the adhesive is dry, the boards are stacked and stored under their own weight; no pressure is required to secure the joints. The adhesive application rate is 150±50 g / m². 2 This results in nail-free, recyclable, and fumigation-free wooden pallets.

[0040] Compared with the prior art, the advantages of the present invention are:

[0041] (1) The nail-free, recyclable, fumigation-free wooden pallet provided by this invention uses high-strength wood glue formulated with a specific ratio of EVCL emulsion and VAE emulsion for all connecting structures, making it completely nail-free; the wood material is high-water-resistant, high-strength OSB board, which is formed by four-stage high-temperature heating and pressing, and the pallet can be made without fumigation. The nail-free, recyclable, fumigation-free wooden pallet of this invention has uniform stress distribution at the joints, avoiding damage caused by local stress concentration, and also avoiding loosening or cracking caused by the difference in thermal expansion and contraction coefficients between metal parts and wood. It has good strength and long-term stability, and meets the general technical requirements of GB / T 31148-2022-wooden flat pallets.

[0042] (2) The preparation method of the nail-free recyclable fumigation-free wooden pallet provided by the present invention is simple and does not require drilling, nailing or other processes; and the nail-free recyclable fumigation-free wooden pallet is easy to recycle and use after being scrapped. The scrapped pallet can be crushed into wood shavings, screened and then processed and used again. Attached Figure Description

[0043] Figure 1This is a schematic diagram of a nail-free, recyclable, fumigation-free wooden pallet according to Embodiment 1 of the present invention. Detailed Implementation

[0044] To enable those skilled in the art to clearly and completely understand the technical solution of the present invention, the present invention will be further described in detail below with reference to embodiments. Obviously, the embodiments described herein are only for explaining the present invention and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0045] This invention provides a nail-free, recyclable, and fumigation-free wooden pallet, comprising longitudinal beams, pad blocks, and flooring. The longitudinal beams and pad blocks, and the pad blocks and flooring are bonded together with high-strength wood adhesive. The high-strength wood adhesive is a two-component formulation system, with component A being a water-based adhesive and component B being a curing agent. The formulation of component A is as follows:

[0046] Ethylene-vinyl chloride copolymer emulsion (EVCL emulsion): 25-35 parts;

[0047] Ethylene-vinyl acetate copolymer emulsion (VAE emulsion): 10-20 parts;

[0048] Plasticizer: 1.0-3.0 parts;

[0049] Wetting agent: 0.1-0.5 parts;

[0050] Calcium carbonate: 20-30 parts;

[0051] Defoamer: 0.1-0.3 parts;

[0052] Fungicide: 0.1-0.3 parts.

[0053] In some examples, the bonding between the longitudinal beam and the pad, and between the pad and the slab, is achieved by applying adhesive using a brushing process, with an adhesive application rate of 150±50 g / m. 2 .

[0054] In some examples, the nail-free, recyclable, fumigation-free wooden pallet is made of OSB board, meaning the longitudinal beams, spacers, and decking are constructed from OSB board; the entire OSB board is pre-bonded to the required thickness with an adhesive application rate of 150±50 g / m². 2 After the glue cures, it is cut into pads; the formula of the OSB board is as follows:

[0055] Surface layer: Wood shavings 192 kg / m² 3 MDI 6.5-10.0 kg / m³ 3 EVCL emulsion 2.0-7.0 kg / m³ 3 Emulsified paraffin wax 3-8 kg / m3 ;

[0056] Core layer: 375 kg / m³ wood shavings 3 MDI 8.5-15.0 kg / m³ 3 EVCL emulsion 3.0-8.0 kg / m 3 2-5 kg / m³ of molten paraffin 3 .

[0057] The OSB board is manufactured using the following process:

[0058] After mixing and laying the adhesive, a four-stage hot pressing process is carried out. The hot pressing factor during the four-stage hot pressing process is 8-12 s / mm.

[0059] The temperatures for the four-stage hot pressing process are as follows: 230-240℃ (stage 1), 225-235℃ (stage 2), 215-225℃ (stage 3), and 190-195℃ (stage 4).

[0060] The thickness of the prepared OSB board is 14-20 mm.

[0061] In some examples, the plasticizer includes, but is not limited to, at least one of dioctyl phthalate (DOP / DEHP), dibutyl phthalate (DBP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), dioctyl adipate (DOA), dioctyl sebacate (DOS), dioctyl azelate (DOZ), tricresyl phosphate (TCP), triphenyl phosphate (TPP), and trioctyl phosphate (TOP).

[0062] In some examples, the wetting agent includes, but is not limited to, at least one of alkylphenol polyoxyethylene ether (APEO), polyether ether ketone (PEEK), polyimide (PI), organically modified polysiloxane, phosphate ester, and methyl carboxylate.

[0063] In some examples, the calcium carbonate has a particle size of 300-800 mesh; the calcium carbonate in the wood glue can significantly reduce production costs while providing structural strength.

[0064] In some examples, the defoamer includes, but is not limited to, at least one of polydimethylsiloxane, polyether-modified polysiloxane, glycerol polyoxypropylene ether, polyoxyethylene polyoxypropylene glycerol ether, polyoxyethylene polyoxypropylene propylene glycol ether, vinyl bis-stearamide, and sorbitan monooleate.

[0065] In some examples, the bactericide includes, but is not limited to, at least one of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 3-iodo-2-propynyl butylcarbamate, 2,2-dibromo-3-azolidinamide, and 2-mercaptobenzothiazole sodium salt.

[0066] Example 1

[0067] A nail-free, recyclable, and fumigation-free wooden pallet is prepared according to the following steps:

[0068] S1. Prepare high-strength, high-water-resistant OSB boards that meet the requirements of GB / T 41715-2022 standard for heavy-duty oriented strand board (OSB / 4 type) under humid conditions. The formula is shown in Table 1.

[0069] Table 1: Formulation of High-Strength, High-Water-Resistant OSB Board

[0070]

[0071] The manufacturing process of high-strength, high-water-resistant OSB boards is as follows:

[0072] Hot pressing factor: 8.5 s / mm;

[0073] Hot pressing temperatures: 230℃ (stage 1), 225℃ (stage 2), 220℃ (stage 3), 190℃ (stage 4);

[0074] High-strength, high-water-resistant OSB board thickness: 15 mm.

[0075] S2. Test the performance of oriented OSB boards: Test the static bending strength, static bending modulus, internal bond strength, internal bond strength after boiling water test, and 24-h water absorption swelling rate of the boards prepared in S1 according to the requirements of GB / T 41715-2022 standard.

[0076] S3. Prepare high-strength wood glue, wherein component A of the high-strength wood glue has the following formula:

[0077] EVCL emulsion (Yunnan Zhengbang 503, 50% solids content): 30 parts;

[0078] VAE emulsion (Yunnan Zhengbang 521M, 50% solid content): 15 parts;

[0079] Plasticizer (DOP): 1.9 parts;

[0080] APEO (a wetting agent): 0.1 parts;

[0081] Calcium carbonate (600 mesh): 20 parts;

[0082] Defoamer (polyether-modified polysiloxane): 0.1 parts;

[0083] Fungicide (a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one in a mass ratio of 2:1): 0.5 parts;

[0084] The high-strength wood glue has component B as MDI (Wanhua Chemical PM-200), and the mass ratio of component A to component B is 100:15.

[0085] S4. Cut the high-strength, high-water-resistant OSB board prepared in S1 for use in fabricating flooring and longitudinal beams; use high-strength wood glue to bond the high-strength, high-water-resistant OSB board prepared in S1 to the required thickness, applying the glue by brushing. After brushing, stack the boards and store them to dry. The glue application rate is 150±50 g / m². 2 After the glue has cured, cut it into pads;

[0086] S5, such as Figure 1 As shown, the pallet lining, pads, and longitudinal beams are glued together to the required dimensions to obtain a nail-free, recyclable, fumigation-free wooden pallet. The adhesive is applied by brushing. After brushing, the pallet is stored separately to dry. The adhesive application rate is 150±50 g / m². 2 After the glue has cured, test the wood bonding performance according to DIN EN 204-2001 (by testing the splicing of blocks together).

[0087] S6. Test the performance of the pallet according to GB / T 31148-2022 - General Technical Requirements for Wooden Flat Pallets.

[0088] Comparative Example 1

[0089] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet of Comparative Example 1 are basically the same as those of Example 1, except that the OSB board formulation in step S1 is shown in Table 2.

[0090] Table 2: Formulation of OSB board in Comparative Example 1

[0091]

[0092] The OSB board formulation in Comparative Example 1 does not contain EVCL emulsion, which is the mainstream formulation for OSB board production on the market.

[0093] Comparative Example 2

[0094] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet in Comparative Example 2 are basically the same as those in Example 1, except that the OSB board formulation in step S1 is shown in Table 3.

[0095] Table 3: Formulation of OSB board in Comparative Example 2

[0096]

[0097] In Comparative Example 2, during the preparation of OSB boards, the moisture content of the surface layer wood shavings after mixing the adhesive was 11.0%, and the moisture content of the core layer wood shavings was 5.6%. At this point, due to the high moisture content, blistering occurred in the boards. This problem could be solved by reducing the production rate, but this would severely impact the production speed. Therefore, in this invention, the maximum addition amount of EVCL emulsion is 15 kg / m³ for the surface layer EVCL emulsion. 3 Core layer EVCL emulsion: 8.0 kg / m 3 At this point, the hot-pressing factor is the highest, at 12 s / mm.

[0098] In Examples 1 and Comparative Examples 1-2, the performance data of the OSB board measured in step S2 are shown in Table 4.

[0099] Table 4: Performance test results of OSB boards prepared in Example 1 and Comparative Examples 1-2

[0100]

[0101] In Example 1 and Comparative Examples 1-2, the performance data of the pallet measured by S6 are shown in Table 5.

[0102] Table 5: Performance test results of the wooden pallets prepared in Example 1 and Comparative Examples 1-2

[0103]

[0104] As shown in Table 4, the mainstream OSB board production formula (Comparative Example 1) without EVCL emulsion produces OSB boards with poor mechanical properties, water resistance, and internal bond strength. The corresponding pallets, in bending tests, fail to meet the deflection requirements of GB / T 31148-2022 - General Technical Requirements for Wooden Flat Pallets. However, with the addition of EVCL emulsion (Example 1), the OSB board meets the requirements of GB / T 41715-2022 standard for heavy-duty oriented strand board (OSB / 4 type) under wet conditions, and the corresponding pallets meet the requirements of GB / T 31148-2022 - General Technical Requirements for Wooden Flat Pallets. Increasing the amount of EVCL emulsion can further improve the water resistance of the OSB board and the load-bearing capacity of the pallets, but the moisture content of the wood shavings needs to be monitored. Therefore, the maximum EVCL emulsion addition is 15 kg / m² for the surface EVCL emulsion. 3 Core layer EVCL emulsion: 8.0 kg / m 3 The corresponding hot-pressing factor does not exceed 12 s / mm.

[0105] Comparative Example 3

[0106] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet in Comparative Example 3 are basically the same as those in Example 1, except that in step S3, the formulation of component A of the wood glue is as follows:

[0107] EVCL emulsion (Yunnan Zhengbang 503, 50% solids content): 35 parts;

[0108] VAE emulsion (Yunnan Zhengbang 521M, 50% solid content): 10 parts;

[0109] Plasticizer (DOP): 1.9 parts;

[0110] APEO (a wetting agent): 0.1 parts;

[0111] Calcium carbonate (600 mesh): 20 parts;

[0112] Defoamer (polyether-modified polysiloxane): 0.1 parts;

[0113] Fungicide (a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one in a mass ratio of 2:1): 0.5 parts.

[0114] Comparative Example 4

[0115] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet in Comparative Example 4 are basically the same as those in Example 1, except that in step S3, the formulation of component A of the wood glue is as follows:

[0116] EVCL emulsion (Yunnan Zhengbang 503, 50% solids content): 25 parts;

[0117] VAE emulsion (Yunnan Zhengbang 521M, 50% solid content): 20 parts;

[0118] Plasticizer (DOP): 1.9 parts;

[0119] APEO (a wetting agent): 0.1 parts;

[0120] Calcium carbonate (600 mesh): 20 parts;

[0121] Defoamer (polyether-modified polysiloxane): 0.1 parts;

[0122] Fungicide (a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one in a mass ratio of 2:1): 0.5 parts.

[0123] Comparative Example 5

[0124] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet of Comparative Example 5 are basically the same as those of Example 1, except that in step S3, the ratio of component A to component B (mass ratio) of the wood glue is 100:12.5.

[0125] Comparative Example 6

[0126] The preparation steps of the nail-free, recyclable, fumigation-free wooden pallet in Comparative Example 6 are basically the same as those in Example 1, except that in step S3, the ratio of component A to component B (mass ratio) of the wood glue is 100:20.

[0127] In Examples 1 and Comparative Examples 3-6, the wood bonding performance tested in step S5 is shown in Table 6.

[0128] Table 6: Test results of wood bonding performance in Examples 1 and Comparative Examples 3-6

[0129]

[0130] During transportation, the wood-glued joints of the pallet are subjected to stress in various directions and exposed to different temperature and humidity conditions. Although the product performance specifications of the pallet do not include technical requirements for this aspect, the performance of each joint must meet the aforementioned transportation requirements. As can be seen from the data in Table 6, the performance specifications of each joint in the wood of this invention meet the requirements of DIN EN 204 grade D4 for wood-glued adhesives.

[0131] Comparing the data from Example 1 and Comparative Examples 3-4, it can be seen that increasing the EVCL ratio reduces the open time of the adhesive. Therefore, in formulating woodworking adhesives according to this invention, the maximum proportion of EVCL emulsion in component A is limited to 35 parts, and the minimum proportion of VAE emulsion is limited to 10 parts. Otherwise, the open time will be too short, affecting the application of adhesives during production. Increasing the VAE ratio increases the open time of the adhesive, but reduces the bonding strength. Therefore, in formulating woodworking adhesives according to this invention, the minimum proportion of EVCL emulsion in component A is limited to 25 parts, and the maximum proportion of VAE emulsion is limited to 20 parts. Otherwise, the strength will be insufficient and will not meet the design requirements.

[0132] Comparing the data from Example 1 and Comparative Examples 5-6, it can be seen that when the mass ratio of component A to component B is 100:12.5, the strength is insufficient and cannot meet the requirements of DIN EN 204 standard D4. Therefore, this invention limits the mass ratio of component A to component B to a minimum of 100:15. Increasing the mass ratio of component A to component B can improve the strength and water resistance of the adhesive, but increasing the mass ratio of component A to component B from 100:15 to 100:20 does not significantly improve the performance. Considering cost factors, this invention limits the mass ratio of component A to component B to a maximum of 100:20.

[0133] In summary, the nail-free, recyclable, fumigation-free wooden pallet of the present invention comprises longitudinal beams, spacers, and planks. The longitudinal beams and spacers, and the spacers and planks, are bonded together using a high-strength wood adhesive formulated with a specific ratio of EVCL and VAE emulsions, completely eliminating the need for nails and thus facilitating recycling and reprocessing. The present invention uses a four-stage hot-pressing process at 190-240℃ to prepare high-strength, highly water-resistant OSB board as the pallet's wood material. Further combined with a specific formulation of high-strength wood adhesive, the prepared wooden pallet meets both the EU IPPC fumigation-free standard and the general technical requirements of GB / T 31148-2022 - Wooden Flat Pallets.

[0134] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A nail-free, recyclable, fumigation-free wooden pallet, characterized in that, The system includes longitudinal beams, spacers, and planks, with the longitudinal beams and spacers, and the spacers and planks bonded together using high-strength wood adhesive. The high-strength wood adhesive is a two-component formulation system, with component A being a water-based adhesive and component B being a curing agent. The formulation of component A is as follows: Ethylene-vinyl chloride copolymer emulsion: 25-35 parts; Ethylene-vinyl acetate copolymer emulsion: 10-20 parts; Plasticizer: 1.0-3.0 parts; Wetting agent: 0.1-0.5 parts; Calcium carbonate: 20-30 parts; Defoamer: 0.1-0.3 parts; Fungicide: 0.1-0.3 parts.

2. The nail-free, recyclable, fumigation-free wooden pallet according to claim 1, characterized in that, The mass ratio of component A to component B is 100:(15-20).

3. The nail-free, recyclable, fumigation-free wooden pallet according to claim 1, characterized in that, The bonding between the longitudinal beam and the pad, and between the pad and the paving board, is achieved by applying adhesive using a brushing process, with an adhesive application rate of 150±50 g / m². 2 .

4. The nail-free, recyclable, fumigation-free wooden pallet according to claim 1, characterized in that, The nail-free, recyclable, fumigation-free wooden pallet is made of OSB board.

5. A nail-free, recyclable, fumigation-free wooden pallet according to claim 4, characterized in that, The OSB board has the following formula: Surface layer: Wood shavings 192 kg / m² 3 MDI 6.5-10.0 kg / m³ 3 EVCL emulsion 2.0-7.0 kg / m³ 3 Emulsified paraffin wax 3-8kg / m 3 ; Core layer: 375 kg / m³ wood shavings 3 MDI 8.5-15.0 kg / m³ 3 EVCL emulsion 3.0-8.0 kg / m 3 2-5 kg / m³ of molten paraffin 3 .

6. A nail-free, recyclable, fumigation-free wooden pallet according to claim 5, characterized in that, The OSB board is manufactured using the following process: After mixing and laying the adhesive, a four-stage hot pressing process is carried out. The hot pressing factor of the four-stage hot pressing process is 8-12 s / mm, and the temperatures of the four-stage hot pressing process are 230-240℃, 225-235℃, 215-225℃, and 190-195℃ respectively. The thickness of the prepared OSB board is 14-20 mm.

7. A nail-free, recyclable, fumigation-free wooden pallet according to claim 4, characterized in that, High-strength wood glue is used to pre-bond the entire OSB board to the required thickness, with an glue application rate of 150±50 g / m². 2 After the glue has cured, it is cut into pads.

8. A nail-free, recyclable, fumigation-free wooden pallet according to claim 1, characterized in that, The calcium carbonate has a particle size of 300-800 mesh.

9. A nail-free, recyclable, fumigation-free wooden pallet according to claim 1, characterized in that, The plasticizer includes, but is not limited to, at least one of dioctyl phthalate, dibutyl phthalate, diisononyl phthalate, diisodecyl phthalate, dioctyl adipate, dioctyl sebacate, dioctyl azelate, tricresyl phosphate, triphenyl phosphate, and trioctyl phosphate; and / or, The wetting agent includes, but is not limited to, at least one of alkylphenol polyoxyethylene ether, polyether ether ketone, polyimide, organically modified polysiloxane, phosphate ester, and methyl carboxylate; and / or, The defoamer includes, but is not limited to, at least one of polydimethylsiloxane, polyether-modified polysiloxane, glycerol polyoxypropylene ether, polyoxyethylene polyoxypropylene glycerol ether, polyoxyethylene polyoxypropylene propylene glycol ether, vinyl bis-stearamide, and sorbitan monooleate; and / or, The bactericides include, but are not limited to, at least one of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 3-iodo-2-propynyl butylcarbamate, 2,2-dibromo-3-azolidinamide, and 2-mercaptobenzothiazole sodium salt.

10. The method for preparing the nail-free, recyclable, fumigation-free wooden pallet according to any one of claims 1-9, characterized in that, Includes the following steps: Formulate wood glue for nail-free bonding; OSB boards are cut to size for use in fabricating flooring and longitudinal beams; Use high-strength wood adhesive to bond the OSB boards to the required thickness, with an adhesive application rate of 150±50 g / m². 2 After the glue has cured, cut it into pads; Bond the pallet boards, pads, and longitudinal beams to the required dimensions, applying adhesive at a rate of 150±50 g / m². 2 This results in nail-free, recyclable, and fumigation-free wooden pallets.

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