Bearing wood for ship fuel cabin and preparation method of bearing wood

Abstract

The invention discloses bearing wood for a ship fuel cabin and a preparation method of the bearing wood, and belongs to the technical field of laminated wood plate manufacturing. The preparation method comprises the following steps: S1, vacuum pressurized impregnation: vacuumizing a veneer under negative pressure, injecting an adhesive, and carrying out pressurized impregnation treatment and glue draining to obtain a modified veneer; s2, drying and pre-pressing are conducted, specifically, the modified veneer is laid and pre-pressed after being dried at low temperature, and an assembly plate is obtained; s3, pressing and curing: carrying out gradient pressure-rising and temperature-rising pressing and curing on the assembly plate to obtain the laminated wood; and S4, waste heat cold pressing and curing are conducted, specifically, after the pressed and cured laminated wood is subjected to pressure relief, a single plate with the double faces coated with glue is laid between the two pieces of obtained laminated wood, and cold pressing treatment is conducted to obtain the bearing wood. According to the scheme, the bearing wood prepared through the method is excellent in mechanical property, flame retardance and insulativity, the preparation efficiency of the bearing wood is greatly improved, energy waste is reduced, and the application range of the bearing wood is wider.

Description

Technical Field

[0001] The present application relates to a load-bearing wood for a ship fuel tank and a preparation method thereof, belonging to the technical field of laminated wood manufacturing. Background Art

[0002] The load-bearing wood for ships is applied to large ship fuel tanks such as steamships and is used to support independent liquid cargo tanks. Due to being in a severe working environment for a long time, it has to bear relatively complex liquid cargo tank loads; in order to protect the safety of the fuel tank, the material must meet relatively high compressive and shear strengths, a low linear expansion coefficient, low density, moisture absorption, friction coefficient, heat conduction coefficient, a large allowable working temperature range, and the insulation performance of the support material.

[0003] Traditional laminated wood is made from natural wood as raw material. The selected beech wood is cut into thin slices, impregnated with phenolic resin under vacuum, and cured after being pressed by a hot press. This processing technology of high-temperature and high-pressure compaction and curing plasticizes the wood; however, during use, it has problems such as being prone to mildew and deterioration, poor mechanical properties of the product, and the inability to ensure the overall uniformity of bonding and forming; even when using imported laminated wood from abroad, there are still problems such as a long supply cycle of laminated wood and a shortage of material sources; and the maximum thickness of laminated wood that can be pressed in the world currently is 320 mm, and in most use scenarios, the standard use size must be achieved through bonding. Therefore, it is of great significance to study how to improve the preparation method of laminated wood and the optimal glue holding amount of veneer during impregnation, reduce the preparation cost of laminated wood, and shorten the supply cycle of laminated wood. Summary of the Invention

[0004] In order to solve the above problems, a load-bearing wood for a ship fuel tank and a preparation method thereof are provided. This method can improve the warping characteristics of laminated wood, improve mechanical properties, simplify the preparation method, shorten the preparation cycle of laminated wood, improve production efficiency, and solve the problem of the long supply cycle faced by the current load-bearing wood for ships.

[0005] According to one aspect of the present application, a preparation method of a load-bearing wood for a ship fuel tank is provided, including the following steps:

[0006] S1. Vacuum pressure impregnation: The veneer is evacuated under negative pressure and then injected with an adhesive, and subjected to pressure impregnation treatment and draining of glue to obtain a modified veneer;

[0007] S2. Drying and pre-pressing: The modified veneer is dried at a low temperature and then paved and pre-pressed to obtain a billet board;

[0008] S3. Pressing and curing: The billet board is subjected to gradient pressure increase and temperature increase for pressing and curing to obtain laminated wood;

[0009] S4. Residual heat cold pressing and curing: After releasing the pressure of the pressed and cured laminated wood, veneers with double-sided glue are laid between the two obtained laminated woods, and the load-bearing wood is obtained through cold pressing treatment.

[0010] The process of gradient pressure increase and temperature increase for pressing and curing in step S3 is as follows:

[0011] (1) Under the initial conditions of 5 MPa and 100 °C, perform 4 - 6 continuous pressure increases, with each pressure increase ranging from 1 - 2 MPa, and keep the pressure for 10 - 20 min after each pressure increase;

[0012] (2) Maintain the pressure and increase the temperature to 130 - 140 °C, and keep the temperature for 10 - 30 min;

[0013] (3) Maintain the pressure, increase the temperature to 160 - 170 °C, keep the temperature for 10 - 30 min, and stop heating.

[0014] Specifically, the pressure-holding time after each pressure increase in step (1) of S3 is related to the thickness of the assembled board, and the required pressure-holding time after each pressure increase is 3.4 min / mm; the heat-insulating time in steps (2) and (3) is related to the thickness of the assembled board, and the required heat-insulating time is 6 min / mm, and the total time does not exceed 30 min.

[0015] Specifically, in step (2) of step S3, when the core layer temperature > 130 °C, start heat preservation; in step (3) of step S3, when the core layer temperature > 160 °C, start heat preservation, and keep the core layer temperature not exceeding 165 °C to prevent the wood from carbonizing.

[0016] In this solution, during the pressing and curing process, it is divided into three stages for gradient pressure increase and temperature increase for pressing and curing: In the first stage, the assembled board is pressed, and 4 - 6 staged pressure increase operations are required until the assembled board is pressed to the specified thickness. The main function of this stage is to enable the escape of moisture and air in the assembled board, so that the adhesive can flow evenly along with the evaporation trajectory of moisture and other substances before curing, and be evenly dispersed to all parts of the material, improving the uniformity and overall adhesive holding capacity of the material during pressing and forming; in the second stage, when the temperature is increased to 130 - 140 °C under the maintained pressure, the assembled board can be softened and the adhesive can be preliminarily cured, and while maintaining the pressed thickness of the assembled board, the laminated wood can be preliminarily shaped to ensure that the material will not be misaligned during the pressure-holding process; in the third stage, continue to maintain the pressure, further increase the temperature while maintaining the pressed thickness of the assembled board to make the adhesive fully cured, eliminate the internal stress and self-elastic ability of the wood in the assembled board, and obtain a laminated wood with stable thickness and not easily deformed.

[0017] During the three-stage pressing and curing process, by gradually increasing the temperature and pressure, the thickness uniformity of each veneer in the pressed blank board can be ensured, thus guaranteeing the overall uniformity of the laminated board. This makes the finally obtained laminated wood have good mechanical properties and is not prone to phenomena such as delamination, collapse, or splitting of the laminated wood. At the same time, due to the filling and sealing of the board by the adhesive, the sealing, waterproof, and insulation properties of the laminated wood are also improved.

[0018] The vacuum-pressure impregnation process adopted in this solution enables the adhesive to fully penetrate into the micropores of the wood veneer by controlling the vacuum degree and pressure conditions. Under vacuum conditions, part of the air, free water, and adsorbed water inside the veneer are extracted, making the overall pressure inside the cells lower than the atmospheric pressure. After injecting the glue, by applying pressure, it is easier for the liquid molecules of the adhesive to overcome the capillary resistance, creating good conditions for the penetration of the adhesive and reducing the interfacial defects caused by water and air. At the same time, the pore structure inside the veneer becomes more open, and the adhesive is more likely to enter the tiny pores, making the adhesive more evenly distributed in the veneer. In addition, under vacuum conditions, the morphology of the cells will become uniform, and the two phospholipid membranes on the inner side of the cell wall will also be in a semi-open and uniform state. Since the substances inside the cells cannot move in a vacuum, the repulsion reaction of phospholipids cannot play a role, enabling the liquid molecules in the adhesive to overcome the capillary resistance and enter the micropores of the veneer. During the pressure impregnation process, the pressure makes the adhesive evenly diffuse inside the board, avoiding too much or too little adhesive locally, and further compressing the possibly remaining bubbles, ensuring that the adhesive fills all the pores and making the adhesive tightly combine with the inner wall of the veneer pores to form a uniform and dense sealing layer. As a result, the product will not have abnormal conditions due to excessive water absorption during use, avoiding the water absorption and swelling of marine bearers and improving the stability and safety of the fuel tank.

[0019] Adopting the pre-pressing process with temperature before pressing can solve the problem of uneven stress in the veneer, and the warping performance of the veneer is significantly improved. At the same time, it reduces the brittleness of the veneer and prevents the veneer from cracking during the subsequent pressing and curing process. In addition, during the pre-pressing process, due to a small degree of temperature and pressure increase treatment on the blank board, although no curing effect will be produced, it can activate the impregnated adhesive, release the bubbles in the adhesive, and further promote the adhesive impregnated on the surface of the board to penetrate deeper into the board under the action of pressure, improving the glue holding capacity of the board.

[0020] After cold pressing and curing using the residual heat of pressing, the strength of the laminated wood obtained in the vertical direction is consistent with that in the bonding direction, and the mechanical properties have good uniformity, which broadens the scope of use of the laminated wood. At the same time, using the residual heat of pressing to cure the laminated wood not only makes full use of the thermal resources in the production process and reduces energy waste, but also eliminates the need for stacking and curing between the laminated woods spliced into load-bearing woods, effectively saving production time, improving production efficiency, and alleviating the problem of the long supply cycle of marine load-bearing woods in the market to a certain extent.

[0021] Optionally, by weight, the adhesive described in step S1 is prepared from the following components: 100-500 parts of alcohol-soluble phenolic resin, 10-25 parts of epoxy resin, 2-5 parts of curing agent, and 10-50 parts of aramid dispersion;

[0022] Among them, the mass ratio of the alcohol-soluble phenolic resin to the epoxy resin is (20-30):1.

[0023] As the main component of the adhesive, the molecular chain of the alcohol-soluble phenolic resin is linearly arranged, with good fluidity, and can spread more evenly on the surface of the veneer, which is more conducive to penetrating into the veneer ducts and fibers. At the same time, the alcohol-soluble phenolic resin has strong wettability and high molecular chain flexibility, and can bind to the surface of the veneer through physical adsorption or van der Waals force, disperse, flow and extend to form a continuous whole under pressure, reduce interface defects, and finally cure under heating conditions to form a dense and uniform impregnated body.

[0024] This solution defines the types and proportions of the components of the adhesive. The alcohol-soluble phenolic resin has good moisture and heat resistance, and the epoxy resin has good toughness and waterproof performance. At the same time, the two resins and aramid act together. With the participation of the curing agent, the alcohol-soluble phenolic resin and the epoxy resin can crosslink after pressure and temperature increase curing, further improving the weather resistance and mechanical properties of the composite of the adhesive and the board, and forming a high-performance adhesive with high strength, high toughness, moisture resistance, insulation and fire protection.

[0025] This solution achieves the best effect by adjusting the proportions of the above components, significantly improving the comprehensive performance of the material. When the ratio of the alcohol-soluble phenolic resin to the epoxy resin is too high, there are problems such as high strength but large brittleness and insufficient flexibility of the obtained board. When the ratio of the two is too low, on the one hand, the strength of the board will decrease due to the high addition amount of epoxy, and on the other hand, the dispersion of the resin will also be affected, thereby reducing the uniformity of the performance of the final impregnated product.

[0026] Specifically, the average molecular weight of the alcohol-soluble phenolic resin is 1000-1200 g / mol, the average molecular weight of the epoxy resin is 3700-5400 g / mol, and the mass fraction of aramid in the aramid dispersion is 2‰-5‰.

[0027] The phenolic resin under this molecular weight limit can overcome the capillary resistance under vacuum conditions, infiltrate into the microstructure of wood, and penetrate more efficiently into the cell cavities and cell walls of wood under high-pressure conditions, filling the pores and microcracks of wood, thereby improving the integrity of the microstructure of wood and ultimately improving the mechanical properties of laminated wood and load-bearing wood.

[0028] Epoxy resin and phenolic resin form crosslinks during the process of heating and pressurizing, improving the bonding strength and further enhancing the water resistance and durability of load-bearing wood.

[0029] Specifically, the curing agent is one or more of phenolic resin, dicyandiamide, hydrazide curing agents (such as adipic dihydrazide), and phthalic anhydride.

[0030] Specifically, the preparation process of the adhesive is as follows: Mix epoxy resin and phenolic resin together in proportion, stir well to avoid local concentration being too high or too low, and at the same time do not over-stir to avoid introducing too many bubbles. After mixing, add an appropriate amount of curing agent and mix evenly, and finally add aramid dispersion.

[0031] Preferably, the aramid is para-aramid, and para-aramid can make the strength and hardness of the board higher. At the same time, it brings good insulation performance to the board.

[0032] Optionally, the negative pressure condition for single veneer vacuuming in step S1 is 0.04 - 0.08 MPa, and the negative pressure holding time is 30 - 60 min;

[0033] The conditions for single veneer pressure impregnation treatment are 0.68 - 3 MPa, and the pressure holding time is 2 - 4 h.

[0034] The negative pressure conditions and pressure conditions defined in this solution can enable the adhesive to fully penetrate into the interior of the single veneer and have a more uniform distribution; if the negative pressure condition fails to reach 0.08 MPa, the adhesive's ability to overcome capillary resistance will not achieve an ideal effect, and there will be a problem of non-uniform distribution; if the pressure in the pressure condition is too high, it may damage the cell wall of the wood or cause it to break, which is not conducive to the subsequent pressure curing process, and may even lead to inconsistent deformation of the assembled board during pressing, resulting in instability or easy deformation of the laminated wood or load-bearing wood products.

[0035] Optionally, the single veneer draining time is 0.5 - 1 h.

[0036] Specifically, the single veneer draining process can be blowing and / or rotating draining.

[0037] Optionally, in step S3, the total time of the heating process in process (2) is determined by the thickness of the assembled board, and the required time for the heating process is 2.5 min / mm; the total time of the heating process in process (3) is determined by the thickness of the assembled board after pressing and shaping, and the required time for the heating process is 2.5 min / mm.

[0038] Specifically, the meaning of 2.5 min / mm is that for every 1 mm increase in the thickness of the laminated wood, the corresponding heating time increases by 2.5 min.

[0039] Optionally, in step S2, the low-temperature drying conditions are a temperature of 55 - 75 °C and an air relative humidity of 30 - 40%; the pre-pressing process is carried out under the conditions of 65 - 85 °C and 1 - 4 MPa for 4 - 12 h.

[0040] Pre-pressing the assembled board under these conditions can make the assembled board be uniformly stressed in all directions and maintain this stress for a period of time, enabling the internal conduits and cell arrangements in the wood to be more uniform and dense without damaging the cell walls inside each veneer, improving the uniformity of the veneer stress, and reducing brittleness, providing better internal conditions for subsequent pressure curing.

[0041] Optionally, the pressure for the cold pressing treatment in step S4 is 10 - 18 MPa. After standing for 1 - 2 h, it is stacked and stored for 7 d.

[0042] Optionally, the veneer is preferably a beech veneer with a moisture content of 6 - 8%; the modified veneer is dried at low temperature to a moisture content of ≤5% after modification.

[0043] Selecting beech veneer with high hardness as the raw material for the load-bearing wood, under the combined action with the cured adhesive, it has the characteristics of not being easily deformed and having high mechanical strength, meeting the requirements of the load-bearing wood for ship fuel tanks.

[0044] Optionally, the paving method in step S2 is that the fiber directions of the veneers in the same layer are the same, and the fiber directions between layers are perpendicular; this paving method can make the laminated wood have equivalent mechanical properties in two directions perpendicular to the thickness direction, improving the adaptability of the laminated wood to pressures in all directions during use.

[0045] In step S4, the paving method of the veneer is as follows: the fiber directions of the two veneers at the end faces of the laminated wood on the upper and lower sides are the same, and the fiber direction of the middle veneer is perpendicular to the two veneers at the end faces of the laminated wood.

[0046] This paving method can ensure the consistency of the stress in each part of the load-bearing wood in the thickness direction, preventing the load-bearing wood from deforming or breaking due to inconsistent stress when stressed.

[0047] According to another aspect of the present application, a load-bearing wood for a ship fuel tank is provided, which is prepared by the above method.

[0048] The beneficial effects of the present application include but are not limited to:

[0049] 1. According to the preparation method of the ship fuel tank bearing wood of the present application, the wood veneer is modified by the vacuum pressure impregnation method. By defining the pressure conditions of vacuum and pressure, it is possible to save 4 to 8 times the impregnation time compared with normal temperature and pressure impregnation under the premise of the same adhesive holding amount, effectively improving the production efficiency of the ship bearing wood.

[0050] 2. According to the preparation method of the ship fuel tank bearing wood of the present application, after the pressing is completed, the laminated wood is cured and spliced by using the residual temperature of pressing, saving the time for stacking and curing the laminated wood before splicing, without affecting the mechanical properties of the ship bearing wood. It not only improves the production speed but also reuses the heat energy required during pressing, reducing energy waste, fully improving the production efficiency of the ship bearing wood, and alleviating the problem of the long supply cycle of the ship bearing wood.

[0051] 3. According to the preparation method of the ship fuel tank bearing wood of the present application, by combining the warm pre-pressing process with the gradient temperature and pressure rising process, the problems of uneven stress and warping of the veneer are solved, avoiding the occurrence of delamination, collapse or splitting of the laminated wood during the pressing process, and improving the mechanical properties of the laminated wood. At the same time, it improves the uniform distribution of the adhesive attached to the board inside the board, improves the impregnation and sealing effect of the adhesive on the micro-pores in the board, and further reduces the water absorption rate and improves the insulation performance of the bearing wood product. At the same time, the paving method defined in this solution makes the mechanical properties of all directions of the finally obtained ship bearing wood equivalent, with good uniformity, and can be applied in various size situations, expanding the use range of the bearing wood.

[0052] 4. According to the preparation method of the ship fuel tank bearing wood of the present application, by combining the component limitation of the adhesive with the preparation process conditions, the uniform distribution of the adhesive inside and between the wood veneers is realized, not only improving the final mechanical properties, waterproof and flame retardant properties of the bearing wood, but also improving the service durability of the laminated wood, making the carbon sequestration effect of tree growth and wood use more lasting, promoting the sustainable use of forest resources, maximizing its carbon sequestration benefit, and reducing the carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0054] Figure 1 is the fluorescence photograph of the modified veneer in the experimental example of the present application;

[0055] Figure 2 is the schematic diagram of the paving method of the veneer and laminated wood involved in the embodiment of the present application. Specific embodiments

[0056] The present application will be described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0057] Unless otherwise specified, the raw materials in the embodiments and comparative examples of the present application are purchased through commercial channels.

[0058] Unless otherwise specified, the methods used in the embodiments and comparative examples of the present application are conventional methods in the prior art.

[0059] In the following embodiments, the average molecular weight of the alcohol-soluble phenolic resin used is 1100 g / mol, the average molecular weight of the epoxy resin is 4500 g / mol, and the mass fraction of aramid in the aramid dispersion is 3‰.

[0060] In the following embodiments and comparative examples, the laying method of the veneer in step S4 and the laminated wood is as Figure 2 shown.

[0061] Example 1

[0062] S1. Vacuum pressure impregnation: Place the veneer in a modification tank, evacuate to maintain a negative pressure of 0.08 MPa for 60 min, inject the adhesive to submerge the veneer by 10 cm, perform impregnation treatment under a pressure of 3 MPa for 4 h, and perform air blowing and rotary drain treatment for 1 h to obtain a modified veneer;

[0063] S2. Drying and pre-pressing: Dry the modified veneer in a balancing machine at a low temperature of 70 °C for 6 h. When the moisture content of the veneer ≤ 5%, perform laying. The laying method is that the fiber directions of the veneers in the same layer are the same, and the fiber directions between layers are perpendicular. Then transfer to a pre-press and pre-press at 80 °C for 12 h to obtain a billet board;

[0064] S3. Pressing and curing:

[0065] (1) Place the billet board in a hot press. The pressure of the hot press is 5 MPa, the temperature is 100 °C, and it is pressed 6 times to increase the pressure to 18 MPa to make the thickness of the billet board 50 mm, and keep the pressure for 20 min;

[0066] (2) On the premise of maintaining the pressure at 18 Mpa, raise the temperature to 140 °C and keep the temperature for 20 min;

[0067] (3) On the premise of maintaining the pressure at 18 Mpa, raise the temperature to 170 °C and keep the temperature for 20 min, then stop heating;

[0068] S4. Afterheat cold pressing and curing: After releasing the pressure of the pressed and cured laminated wood, veneers coated with adhesive on both sides are laid between the two obtained billet boards. The laying method of the veneers is that the fiber directions of the two veneers at the end faces of the laminated wood on the upper and lower sides are the same, and the fiber direction of the middle veneer is perpendicular to that of the two veneers at the end faces of the laminated wood. After standing for 2 h at 18 Mpa, it is cooled and stacked for 7 d to obtain the load-bearing wood.

[0069] Among them, the adhesive is prepared from the following components: 500 parts of alcohol-soluble phenolic resin, 25 parts of epoxy resin, 5 parts of curing agent, and 50 parts of aramid dispersion liquid.

[0070] Example 2

[0071] S1. Vacuum pressure impregnation: Place the veneer in a modification tank, evacuate to maintain a negative pressure of 0.04 MPa for 45 min, inject the adhesive to submerge the veneer by 10 cm, perform impregnation treatment under a pressure of 2 MPa for 3 h, and perform air blowing and rotary glue draining treatment for 45 min to obtain the modified veneer.

[0072] S2. Drying and pre-pressing: Dry the modified veneer in a balancing machine at a low temperature of 65 °C for 5 h. When the moisture content of the veneer ≤ 5%, perform laying. The laying method is that the fiber directions of the veneers in the same layer are the same, and the fiber directions between layers are perpendicular. Then transfer it to a pre-press and pre-press at 70 °C for 8 h to obtain the billet board.

[0073] S3. Pressing and curing:

[0074] (1) Put the billet board into a hot press. The pressure of the hot press is 5 MPa, the temperature is 100 °C, press 5 times to increase the pressure to 14 MPa to make the thickness of the billet board 50 mm, and keep the pressure for 15 min.

[0075] (2) Maintain the pressure and heat up to 135 °C within 125 min, and keep the temperature for 20 min.

[0076] (3) Continue to maintain the pressure, heat up to 162 °C, keep the temperature for 20 min, and stop heating.

[0077] S4. Afterheat cold pressing and curing: After releasing the pressure of the pressed and cured laminated wood, veneers coated with adhesive on both sides are laid between the two obtained billet boards. The laying method of the veneers is that the fiber directions of the two veneers at the end faces of the laminated wood on the upper and lower sides are the same, and the fiber direction of the middle veneer is perpendicular to that of the two veneers at the end faces of the laminated wood. After standing for 1.5 h at a pressure of 15 Mpa, it is cooled and stacked for 7 d to obtain the load-bearing wood.

[0078] Among them, the adhesive is prepared from the following components: 200 parts of alcohol-soluble phenolic resin, 18 parts of epoxy resin, 3 parts of curing agent, and 35 parts of aramid dispersion liquid.

[0079] Example 3

[0080] S1. Vacuum pressure impregnation: Place the veneer in a modification tank, evacuate to a negative pressure of 0.04 MPa and maintain for 30 min, inject the adhesive so that the adhesive covers the veneer by 10 cm, perform impregnation treatment under a pressure of 0.68 MPa for 2 h, and perform air blowing and rotary glue draining treatment for 0.5 h to obtain a modified veneer;

[0081] S2. Drying and pre-pressing: Dry the modified veneer in a balancing machine at a low temperature of 60 °C for 3 h. When the moisture content of the veneer ≤ 5%, perform paving. The paving method is that the fiber directions of the veneers in the same layer are the same, and the fiber directions between layers are perpendicular. Then transfer to a pre-press and pre-press at 60 °C to obtain a pre-assembled board;

[0082] S3. Pressing and curing:

[0083] (1) Place the pre-assembled board in a hot press. The pressure of the hot press is 5 MPa, the temperature is 100 °C, press 4 times and increase the pressure to 10 MPa to make the thickness of the laminate 50 mm, and keep the pressure for 10 min;

[0084] (2) Maintain the pressure and raise the temperature to 130 °C within 125 min;

[0085] (3) Continue to maintain the pressure at 10 MPa, raise the temperature to 160 °C, keep warm for 30 min, and stop heating;

[0086] S4. Cold pressing and curing with residual temperature: After releasing the pressure of the pressed and cured laminated wood, pave a veneer with double-sided adhesive in the middle of the two obtained pre-assembled boards. The paving method of the veneer is that the fiber directions of the two veneers at the end faces of the laminated wood on the upper and lower sides are the same, and the fiber direction of the middle veneer is perpendicular to the two veneers at the end faces of the laminated wood. After standing for 1 h under a pressure of 10 MPa, cool down and stack and store for 7 d to obtain the load-bearing wood;

[0087] Among them, the adhesive is prepared from the following components: 100 parts of alcohol-soluble phenolic resin, 10 parts of epoxy resin, 2 parts of curing agent, and 10 parts of aramid dispersion liquid.

[0088] Example 4

[0089] The difference from Example 3 is that in S1, the negative pressure condition is 0.09 MPa.

[0090] Example 5

[0091] The difference from Example 3 is that in S1, the pressing condition is 0.5 MPa.

[0092] Example 6

[0093] The difference from Example 3 is that the number of parts of alcohol-soluble phenolic resin is 300 parts.

[0094] Example 7

[0095] The difference from Example 3 is that the amount of epoxy resin is 50 parts.

[0096] Comparative Example 1

[0097] The difference from Example 3 is that the veneer modification process is impregnated under normal pressure.

[0098] Comparative Example 2

[0099] The difference from Example 3 is that the veneer is placed in a modification tank, without vacuum pumping, and only pressure impregnation treatment is carried out.

[0100] Comparative Example 3

[0101] The difference from Example 3 is that in S3, after the pressure increase in step (1) is completed, the pressure is maintained, step (2) is omitted, and the temperature is directly raised to 160 °C on the basis of step (1) for curing.

[0102] Comparative Example 4

[0103] The difference from Example 3 is that in S3, in step (1), the process of gradient pressure increase is not adopted, the pressure is directly increased to 10 MPa, and the temperature is raised to 160 °C in a gradient manner, and the pressure is maintained until the specified thickness is reached.

[0104] Comparative Example 5

[0105] The difference from Example 3 is that the laminated wood after pressing and curing is first subjected to cold stacking and curing for 7 days, and then the temperature and pressure are increased for bonding. The bonding conditions are 10 MPa, and the temperature is raised to 160 °C for pressing and curing for 30 min.

[0106] Experimental Example

[0107] The modified veneer obtained in step S1 is weighed, and the impregnation amount and adhesive holding amount of the veneer are calculated. The results are shown in Table 1;

[0108] The mechanical properties of the prepared bearing wood are tested. Among them, the flexural strength and flexural modulus of elasticity are detected according to "ISO 178-2010 Plastics - Determination of flexural properties". The test results are shown in Table 2;

[0109] The water absorption rate, electrical strength and combustion time of the prepared bearing wood are tested. Among them, the water absorption is detected according to the standard "ISO 62-2008 Plastics - Determination of water absorption", the electrical strength is detected according to "IEC 61061-2-1992 Test methods for unimpregnated compact laminated wood for electrical purposes", and the combustion time of the material is detected according to "EN ISO 9239-1 Fire performance of floor coverings". The results are shown in Table 3;

[0110] In addition, modified veneers with adhesive holding amounts of 25%, 35%, and 45% are prepared, and fluorescence photos are taken. The photos are shown in Figure 1。

[0111] Table 1

[0112]

[0113]

[0114] Table 2

[0115]

[0116] Table 3

[0117] Test number Water absorption rate Electrical strength Burning time Example 1 0.14 11.9 18′57″ Example 2 0.27 12.7 17′14″ Example 3 0.32 13.1 16′19″ Example 4 0.5 12.5 16′49″ Example 5 0.29 12 16′33″ Example 6 0.49 13.7 15′48″ Example 7 0.5 10.5 15′01″ Comparative example 1 0.5 11 8′ Comparative example 2 0.46 12.4 17′06″ Comparative example 3 0.41 11.5 13′13″ Comparative example 4 0.38 11.1 11′41″ Comparative example 5 0.44 10.6 10′15″

[0118] It can be seen from the data that the comprehensive performance of the laminated wood obtained in Example 2, including mechanical strength, hydrophobicity and fire resistance, is the best. However, considering various aspects such as comprehensive production cost, technical feasibility, adhesive holding amount of veneer, and various detection performances of the samples, Example 3 is the best. It can be seen that by adjusting the veneer impregnation conditions and pressing conditions of the laminated wood and combining with the specified proportion of adhesive components, the laminated wood material with excellent performances can be obtained. At the same time, for the pressed laminated wood, the residual heat is used for bonding, without the need for additional pressure heating treatment after stacking and cooling. This not only saves the time of stacking and cooling but also eliminates the need to reheat the laminated wood, thus saving energy consumption and improving production efficiency.

[0119] As described above, the above are only the embodiments of the present application. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A method for preparing a support wood for a ship fuel tank, characterized in that: The steps include: S1. Vacuum pressure impregnation: the veneer is vacuumed under negative pressure and then injected with adhesive, and then pressure impregnated and leached to obtain a modified veneer; S2, drying and pre-pressing: the modified veneer is dried at low temperature, then laid and pre-pressed to obtain an assembled board; S3, pressing and curing: pressing and curing the assembled board by gradient pressure and temperature to obtain laminated wood; S4, cold pressing and curing at residual temperature: after releasing the pressure of the pressed and cured laminated wood, a double-sided glue-coated veneer is laid between two laminated woods, and the supporting wood is obtained by cold pressing; The gradient pressure-raising and temperature-raising pressing and curing process in step S3 is as follows: (1) Under the initial conditions of 5 MPa and 100°C, the pressure is continuously increased for 4 to 6 times, with the pressure increase amplitude of each time being 1 to 2 MPa, and the pressure is maintained for 10 to 20 minutes after each pressure increase; (2) Maintaining the pressure, raising the temperature to 130-140°C and keeping it at that temperature for 10-30 minutes; (3) Maintaining the pressure, raise the temperature to 160-170°C, keep warm for 10-30 minutes, and stop heating.

2. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: The adhesive in step S1 is prepared from the following components by weight: 100 to 500 parts of alcohol-soluble phenolic resin, 10 to 25 parts of epoxy resin, 2 to 5 parts of curing agent and 10 to 50 parts of aramid dispersion; Preferably, the mass ratio of the alcohol-soluble phenolic resin to the epoxy resin is (20-30):

1.

3. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: In step S1, the negative pressure condition for vacuuming the single board is 0.04-0.08 MPa, and the negative pressure is maintained for 30-60 minutes; The conditions for the single board pressure impregnation treatment are 0.68-3MPa, and the pressure holding time is 2-4h.

4. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: In step S1, the single board leaching time is 0.5 to 1 hour.

5. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: In step S3, the total time of the heating process in process (2) is determined by the thickness of the assembled plate, and the time required for the heating process is 2.5 min / mm; the total time of the heating process in process (3) is determined by the thickness of the assembled plate, and the time required for the heating process is 2.5 min / mm.

6. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: In step S2, the low-temperature drying time is 3 to 6 hours, the temperature is 60 to 70° C., the relative humidity of the air is 30 to 40%, and the moisture content of the modified veneer after low-temperature drying is ≤5%; The pre-pressing process conditions are 4 to 12 hours at 60 to 80°C and 1 to 4 MPa.

7. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: The pressure of the cold pressing treatment in step S4 is 10-18 MPa, and the temperature is lowered after standing for 1-2 hours, and the mixture is piled and stored for 7 days.

8. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: The veneer is a beech veneer with a moisture content of 6-8%.

9. The method for preparing a support wood for a ship fuel tank according to claim 1, characterized in that: The laying method in step S2 is that the fiber directions of the same layer of veneer are consistent, and the fiber directions of the layers are perpendicular; The paving method of the veneer in step S4 is: the fiber directions of the two veneers on the upper and lower laminated wood end faces are consistent, and the fiber directions of the middle veneer are perpendicular to the two veneers on the laminated wood end faces.

10. A support wood for a ship fuel tank, characterized in that: Prepared according to the method of claims 1 to 9.

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