A cryogenic resistant laminated wood for cryogenic liquid storage tanks and a method of making the same

Abstract

The present application relates to liquefied natural gas ship material technical field, specifically for a kind of low temperature resistant laminated wood for cryogenic liquid storage cabin and its preparation method;In order to reduce the demand for high-quality timber and the environmental problems caused by felling, the modified polyurethane insulation layer is used to prepare the laminated wood with the wood board, which greatly reduces the demand for tree material, effectively reduces the environmental damage caused by felling;And in order to improve the low temperature mechanical properties and thermal insulation performance of the prepared laminated wood, the raw material is modified when preparing the modified polyurethane insulation layer, the siloxane bond and long carbon chain structure are added in the polyurethane structure, the performance of polyurethane foam layer is effectively improved, the bubble structure stability in polyurethane foam layer is improved, so that the foam layer has better thermal insulation performance.

Description

Technical Field

[0001] This invention relates to the field of materials technology for liquefied natural gas (LNG) ships, specifically to a cryogenic laminated wood for cryogenic liquid storage tanks and its preparation method. Background Technology

[0002] In recent years, my country's demand for liquefied natural gas (LNG) has experienced rapid growth, with a growth rate of 50%, bringing tremendous development opportunities to the LNG transportation and storage industry. Because LNG has an extremely low boiling point of -196℃, the temperature needs to be controlled below this low level during transportation and storage to minimize LNG evaporation losses. To achieve this, insulation of LNG tanks and pipelines on transport vessels and storage facilities is essential.

[0003] Currently, LNG transport and storage tanks mainly consist of a cargo tank, a supporting steel structure, and laminated wood placed between the two to provide support and thermal insulation. Among them, this type of laminated wood is mostly made of red beech trees. However, red beech trees grow slowly and the molding process is complex, resulting in long supply cycles and high costs, which seriously limits the cost of LNG transportation. Therefore, it is necessary to overcome this problem in order to meet market demand. Summary of the Invention

[0004] The purpose of this invention is to provide a cryogenic laminated wood for cryogenic liquid storage chambers and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-temperature resistant laminated wood for cryogenic liquid storage tank, which has the following technical features: the low-temperature resistant laminated wood is composed of surface wood boards on both sides and a modified polyurethane insulation layer in the middle.

[0006] The modified polyurethane insulation layer has a thickness of 10-200 mm, and the surface wood panel has a thickness of 10-30% of the modified polyurethane insulation layer thickness.

[0007] Furthermore, the method for preparing the surface wood panel is as follows:

[0008] The wood board is shaped and then impregnated in a mixture of E44 epoxy resin and dicyandiamide. After being pressurized to 1.5-2 MPa and impregnated for 10-15 minutes, excess adhesive is scraped off the surface and then the board is cured and dried in an environment of 90-100℃ for 1-2 hours to obtain the surface wood board.

[0009] The wood board is any one of beech, oak, or birch; the mass ratio of E44 epoxy resin to dicyandiamide in the mixed adhesive is 5:(1-1.5).

[0010] Furthermore, the modified polyurethane insulation layer is composed of 120-135 parts of polyether polyol, 90-120 parts of modified isocyanate, 25-50 parts of glass microspheres, 50-80 parts of glass fiber reinforcement material, 0.5-0.8 parts of silane coupling agent, 12-18 parts of foaming agent, and 0.1-0.8 parts of catalyst.

[0011] Furthermore, the polyether polyol is polytetrahydrofuran ether diol with a weight-average molecular weight of 2000-3000; the silane coupling agent is at least one of KH550 and KH570; and the catalyst is dibutyltin dilaurate.

[0012] Furthermore, the glass microspheres have a diameter of 10-60 micrometers; the glass fiber reinforcement material is a biaxially oriented glass fiber cloth with an areal density of 600-1200 g / m². 2 The foaming agent is either n-butane or n-pentane.

[0013] Furthermore, by weight, the modified isocyanate consists of 50-65% polymethylene polyphenyl isocyanate and 35-50% long-chain isocyanate.

[0014] The average hydroxyl value of the polymethylene polyphenyl isocyanate is 250-600 mg KOH / g;

[0015] The preparation method of the long-chain isocyanate is as follows:

[0016] a. Under a nitrogen atmosphere, tetramethyldihydrodisiloxane was dispersed in chloroform. After stirring and mixing for 5-10 min at room temperature, chloroplatinic acid was added and mixing was continued for 1-2 min. The mixture was then cooled to 5-10°C and added dropwise to a DMF solution containing hexamethylene diisocyanate. During the dropwise addition, the mixture was stirred by ultrasonic vibration. After the dropwise addition was completed, the mixture was heated to 65-68°C and refluxed for 2-8 h. Excess solvent was removed by rotary evaporation. The reaction product was washed 2-3 times with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0017] b. Disperse triphenylmethane triisocyanate in dichloromethane under a nitrogen atmosphere and sonicate for 30-45 min. Then add tin acetate and continue sonication for 2-5 min. Then add 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane dropwise while continuously stirring the mixture. After the addition is complete, heat to 75-82℃ and stir for 2-16 h. Then remove excess solvent by rotary evaporation to obtain the terminal epoxy intermediate.

[0018] c. Disperse the terminal epoxy intermediate in N-methylpyrrolidone under a nitrogen atmosphere, heat to 35-40℃, and sonicate for 1-2 hours. Then, add it dropwise to DMAc containing silicon-modified diisocyanate for 1-4 hours. After the addition is complete, heat the mixture to 78-82℃ and continue stirring for 4-12 hours. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0019] Furthermore, in step a, the mass ratio of tetramethyldihydrodisiloxane, chloroplatinic acid, and hexamethylene diisocyanate is (0.75-0.8):(0.005-0.01):1.

[0020] Furthermore, in step b, the mass ratio of the triphenylmethane triisocyanate, tin acetate, and 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:(0.01-0.02):(2.4-3.0).

[0021] Furthermore, in step c, the mass ratio of the terminal epoxy intermediate to the silicon-modified diisocyanate is 1:(0.55-0.65).

[0022] Furthermore, a method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber includes the following steps:

[0023] S1. Add silane coupling agent to polyether polyol, stir and disperse for 1-2 min, add glass microspheres, stir and mix for 5-8 min, add foaming agent and catalyst, continue mixing for 2-3 min, add modified isocyanate, continue mixing for 1-3 min, and obtain modified polyurethane mixture;

[0024] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add glass fiber reinforcement material into the mold cavity, inject modified polyurethane mixture, heat up to foam and cure, and take it out to obtain low-temperature resistant laminated wood for cryogenic liquid storage chamber.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] In order to reduce the demand for high-quality timber and the environmental problems caused by logging, this invention uses a modified polyurethane insulation layer and wood boards to prepare laminated wood, which significantly reduces the demand for tree materials compared with traditional red beech wood laminate, and effectively reduces the environmental damage caused by logging.

[0027] Furthermore, to improve the low-temperature mechanical properties and thermal insulation performance of the prepared laminated wood, this invention modifies the raw materials during the preparation of the modified polyurethane insulation layer. This invention uses tetramethyldihydrodisiloxane as a raw material to react with hexamethylene diisocyanate, and by controlling the reaction conditions, prepares a silicon-modified diisocyanate containing silicon-oxygen bonds and a long carbon chain structure. Based on this, this invention also utilizes triphenylmethane triisocyanate and 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane containing silicon-oxygen bonds. The reaction yielded a three-armed terminal epoxy intermediate, which was further reacted with silicon-modified diisocyanate to prepare a three-armed long-chain isocyanate with both long carbon chains and silicon-oxygen bonds. The low-temperature resistance provided by the long carbon chains and silicon-oxygen bonds improved the mechanical properties of the foam layer in ultra-low temperature environments. Furthermore, the three-arm structure of the long-chain isocyanate may further enhance the crosslinking complexity of the polyurethane resin, effectively improving the performance of the polyurethane foam layer and enhancing the stability of the bubble structure in the polyurethane foam layer, thereby giving the foam layer better thermal insulation performance. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the embodiments and comparative examples of this invention, the polytetrahydrofuran ether diol used had a weight-average molecular weight of 2000; the glass microspheres used were S60HS type glass microspheres from 3M Company, USA; and the biaxial fabric weight of the glass fibers used was 650 g / m². 2 ;

[0032] The method for preparing the surface wood panels used is as follows:

[0033] Beechwood boards are processed into shapes and then impregnated in a mixture of 5 parts by weight of E44 epoxy resin and 1 part by weight of dicyandiamide. After impregnation at 1.5 MPa for 10 minutes, excess adhesive is scraped off the surface and the boards are cured and dried at 90°C for 1.5 hours to obtain the surface wood board.

[0034] Example 1. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0035] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, then add 30 parts of glass microspheres, stir and mix for 5 min, then add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, then add 90 parts of modified isocyanate, continue mixing for 1 min, and obtain the modified polyurethane mixture;

[0036] The modified isocyanate is composed of 65% polymethylene polyphenyl isocyanate and 35% long-chain isocyanate.

[0037] The preparation method of the long-chain isocyanate is as follows:

[0038] a. By weight, under a nitrogen atmosphere, 0.75 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0039] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 2.4 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0040] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.55 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0041] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0042] Example 2. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0043] Compared with Example 1, this example increases the amount of long-chain isocyanate added in step S1;

[0044] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, then add 30 parts of glass microspheres, stir and mix for 5 min, then add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, then add 90 parts of modified isocyanate, continue mixing for 1 min, and obtain the modified polyurethane mixture;

[0045] The modified isocyanate is composed of 50% polymethylene polyphenyl isocyanate and 50% long-chain isocyanate.

[0046] The preparation method of the long-chain isocyanate is as follows:

[0047] a. By weight, under a nitrogen atmosphere, 0.75 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0048] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 2.4 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0049] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.55 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0050] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0051] Example 3. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0052] Compared with Example 2, this example increases the amount of tetramethyldihydrodisiloxane added in step a;

[0053] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, then add 30 parts of glass microspheres, stir and mix for 5 min, then add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, then add 90 parts of modified isocyanate, continue mixing for 1 min, and obtain the modified polyurethane mixture;

[0054] The modified isocyanate is composed of 50% polymethylene polyphenyl isocyanate and 50% long-chain isocyanate.

[0055] The preparation method of the long-chain isocyanate is as follows:

[0056] a. By weight, under a nitrogen atmosphere, 0.8 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0057] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 2.4 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0058] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.55 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0059] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0060] Example 4. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0061] Compared with Example 2, this example increases the amount of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane added in step b;

[0062] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, then add 30 parts of glass microspheres, stir and mix for 5 min, then add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, then add 90 parts of modified isocyanate, continue mixing for 1 min, and obtain the modified polyurethane mixture;

[0063] The modified isocyanate is composed of 50% polymethylene polyphenyl isocyanate and 50% long-chain isocyanate.

[0064] The preparation method of the long-chain isocyanate is as follows:

[0065] a. By weight, under a nitrogen atmosphere, 0.75 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0066] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 3 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0067] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.55 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0068] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0069] Example 5. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0070] Compared with Example 2, this example increases the amount of silicon-modified diisocyanate added in step c;

[0071] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, then add 30 parts of glass microspheres, stir and mix for 5 min, then add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, then add 90 parts of modified isocyanate, continue mixing for 1 min, and obtain the modified polyurethane mixture;

[0072] The modified isocyanate is composed of 50% polymethylene polyphenyl isocyanate and 50% long-chain isocyanate.

[0073] The preparation method of the long-chain isocyanate is as follows:

[0074] a. By weight, under a nitrogen atmosphere, 0.75 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0075] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 2.4 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0076] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.65 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0077] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0078] Comparative Example 1. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0079] Compared to Example 2, this comparative example uses polymethylene polyphenyl isocyanate instead of modified isocyanate;

[0080] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, add 30 parts of glass microspheres, stir and mix for 5 min, add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, add 90 parts of polymethylene polyphenyl isocyanate and continue mixing for 1 min to obtain modified polyurethane mixture;

[0081] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0082] Comparative Example 2. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber, comprising the following steps:

[0083] Compared to Example 2, this comparative example uses a long-chain isocyanate instead of the modified isocyanate.

[0084] S1. By weight, add 0.5 parts of silane coupling agent to 125 parts of polytetrahydrofuran ether diol, stir and disperse for 1 min, add 30 parts of glass microspheres, stir and mix for 5 min, add 12 parts of n-butane foaming agent and 0.2 parts of dibutyltin dilaurate catalyst, continue mixing for 3 min, add 90 parts of long-chain isocyanate, continue mixing for 1 min, and obtain modified polyurethane mixture;

[0085] The preparation method of the long-chain isocyanate is as follows:

[0086] a. By weight, under a nitrogen atmosphere, 0.75 parts of tetramethyldihydrodisiloxane were dispersed in chloroform. After stirring and mixing for 5 min at room temperature, 0.08 parts of chloroplatinic acid were added and mixed for another 1 min. The mixture was then cooled to 5°C and added dropwise to a DMF solution containing 1 part of hexamethylene diisocyanate. During the addition, the mixture was stirred by ultrasonic vibration. After the addition was completed, the mixture was heated to 68°C and refluxed for 6 h. Excess solvent was removed by rotary evaporation. The reaction product was washed twice with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate.

[0087] b. By weight, 1 part of triphenylmethane triisocyanate was dispersed in dichloromethane under a nitrogen atmosphere and ultrasonically dispersed for 30 min. Then, tin acetate was added and ultrasonically dispersed for another 2 min. Then, 2.4 parts of 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane were added dropwise. The mixed solution was stirred continuously during the dropwise addition. After the dropwise addition was completed, the temperature was raised to 78°C and the reaction was stirred for 12 h. The excess solvent was removed by rotary evaporation to obtain the terminal epoxy intermediate.

[0088] c. Disperse 1 part of terminal epoxy intermediate in N-methylpyrrolidone under nitrogen atmosphere, heat to 40°C, and ultrasonically disperse for 1 h. Then, add it dropwise to DMAc containing 0.55 parts of silicon-modified diisocyanate for 1 h. After the addition is completed, heat the mixture to 80°C and continue stirring for 8 h. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

[0089] S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add 80 parts of glass fiber biaxial cloth into the mold cavity, inject modified polyurethane mixture, foam and cure, and take it out to obtain the low-temperature resistant laminated wood for the cryogenic liquid storage tank.

[0090] Testing: The modified polyurethane mixtures prepared in Examples 1-5 and Comparative Examples 1-2 were injection molded into test specimens, and the density of the test specimens prepared in Examples 1-5 and Comparative Examples 1-2 was tested according to GB / T 1463-2005; the compressive strength of the test specimens prepared in Examples 1-5 and Comparative Examples 1-2 at 20℃ and -196℃ was tested according to GB / T1448-2005; the thermal conductivity of the test specimens prepared in Examples 1-5 and Comparative Examples 1-2 at 20℃ and -196℃ was tested according to ISO 22007-4.

[0091] The test results are shown in the table below:

[0092]

[0093] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0094] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cryogenic laminated wood for use in cryogenic liquid storage chambers, characterized in that: The low-temperature resistant laminated wood consists of surface wood panels on both sides and a modified polyurethane insulation layer in the middle. The modified polyurethane insulation layer has a thickness of 10-200 mm, and the surface wood panel has a thickness of 10-30% of the modified polyurethane insulation layer thickness.

2. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 1, characterized in that: The method for preparing the surface wood panel is as follows: The wood board is shaped and then impregnated in a mixture of E44 epoxy resin and dicyandiamide. After being pressurized to 1.5-2 MPa and impregnated for 10-15 minutes, excess adhesive is scraped off the surface and then the board is cured and dried in an environment of 90-100℃ for 1-2 hours to obtain the surface wood board. The wood board is any one of beech, oak, or birch; the mass ratio of E44 epoxy resin to dicyandiamide in the mixed adhesive is 5:(1-1.5).

3. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 1, characterized in that: The modified polyurethane insulation layer is composed of 120-135 parts of polyether polyol, 90-120 parts of modified isocyanate, 25-50 parts of glass microspheres, 50-80 parts of glass fiber reinforcement, 0.5-0.8 parts of silane coupling agent, 12-18 parts of foaming agent, and 0.1-0.8 parts of catalyst.

4. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 3, characterized in that: The polyether polyol is polytetrahydrofuran ether diol with a weight-average molecular weight of 2000-3000; the silane coupling agent is at least one of KH550 and KH570; and the catalyst is dibutyltin dilaurate.

5. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 3, characterized in that: The glass microspheres have a diameter of 10-60 micrometers; the glass fiber reinforcement material is a biaxially oriented glass fiber cloth with an areal density of 600-1200 g / m². 2 The foaming agent is either n-butane or n-pentane.

6. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 3, characterized in that: By weight, the modified isocyanate consists of 50-65% polymethylene polyphenyl isocyanate and 35-50% long-chain isocyanate; The average hydroxyl value of the polymethylene polyphenyl isocyanate is 250-600 mg KOH / g; The preparation method of the long-chain isocyanate is as follows: a. Under a nitrogen atmosphere, tetramethyldihydrodisiloxane was dispersed in chloroform. After stirring and mixing for 5-10 min at room temperature, chloroplatinic acid was added and mixing was continued for 1-2 min. The mixture was then cooled to 5-10°C and added dropwise to a DMF solution containing hexamethylene diisocyanate. During the dropwise addition, the mixture was stirred by ultrasonic vibration. After the dropwise addition was completed, the mixture was heated to 65-68°C and refluxed for 2-8 h. Excess solvent was removed by rotary evaporation. The reaction product was washed 2-3 times with deionized water at 0-5°C and then vacuum evaporated to constant weight to obtain silicon-modified diisocyanate. b. Disperse triphenylmethane triisocyanate in dichloromethane under a nitrogen atmosphere and sonicate for 30-45 min. Then add tin acetate and continue sonication for 2-5 min. Then add 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane dropwise while continuously stirring the mixture. After the addition is complete, heat to 75-82℃ and stir for 2-16 h. Then remove excess solvent by rotary evaporation to obtain the terminal epoxy intermediate. c. Disperse the terminal epoxy intermediate in N-methylpyrrolidone under a nitrogen atmosphere, heat to 35-40℃, and sonicate for 1-2 hours. Then, add it dropwise to DMAc containing silicon-modified diisocyanate for 1-4 hours. After the addition is complete, heat the mixture to 78-82℃ and continue stirring for 4-12 hours. Then, remove excess solvent by rotary evaporation to obtain long-chain isocyanate.

7. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 6, characterized in that: In step a, the mass ratio of tetramethyldihydrodisiloxane, chloroplatinic acid, and hexamethylene diisocyanate is (0.75-0.8):(0.005-0.01):

1.

8. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 6, characterized in that: In step b, the mass ratio of the triphenylmethane triisocyanate, tin acetate, and 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:(0.01-0.02):(2.4-3.0).

9. The cryogenic laminated wood for a cryogenic liquid storage chamber according to claim 6, characterized in that: In step c, the mass ratio of the terminal epoxy intermediate to the silicon-modified diisocyanate is 1:(0.55-0.65).

10. A method for preparing cryogenic laminated wood for a cryogenic liquid storage chamber as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Add silane coupling agent to polyether polyol, stir and disperse for 1-2 min, add glass microspheres, stir and mix for 5-8 min, add foaming agent and catalyst, continue mixing for 2-3 min, add modified isocyanate, continue mixing for 1-3 min, and obtain modified polyurethane mixture; S2. After processing the surface wood board into shape and placing it on the upper and lower sides of the mold, add glass fiber reinforcement material into the mold cavity, inject modified polyurethane mixture, heat up to foam and cure, and take it out to obtain low-temperature resistant laminated wood for cryogenic liquid storage chamber.

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