Cryogenic heat-insulating flame-retardant polyurethane foam for LNG (liquefied natural gas) storage tank and preparation process thereof

Abstract

The invention relates to the technical field of polyurethane foam, and discloses cryogenic heat-insulating flame-retardant polyurethane foam for an LNG storage tank and a preparation process of the cryogenic heat-insulating flame-retardant polyurethane foam. Comprising the following operation steps: step 1, uniformly mixing polyether polyol, hydroxyl-terminated polybutadiene, a polysiloxane surfactant, a catalyst, flame-retardant phenylphosphine modified silicone oil and deionized water to obtain a component A; 4, 4 '-diphenylmethane diisocyanate and double-end epoxy group modified silicone oil are mixed according to a certain proportion, and a component B is obtained; and 2, adding the component B into the component A, uniformly mixing, and adding into a mold for foaming and forming to obtain the cryogenic heat-insulating flame-retardant polyurethane foam.

Description

Technical Field

[0001] This invention relates to the field of polyurethane foam technology, specifically to a cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks and its preparation process. Background Technology

[0002] Liquefied natural gas (LNG) is a clean and efficient energy source. Its storage requires a cryogenic environment of -162°C. The insulation performance of the storage tank directly determines the energy consumption and operational safety of storage and transportation. Due to its advantages such as low density and low thermal conductivity, polyurethane foam has become one of the core materials for the insulation layer of LNG storage tanks. However, conventional polyurethane foam is prone to embrittlement and cracking under cryogenic conditions, and its inherent flame retardancy is insufficient, making it difficult to meet the stringent safety requirements of storage tanks.

[0003] Existing cryogenic insulation polyurethane foams often improve low-temperature stability by adding inorganic fillers such as glass wool and perlite, but this leads to an increase in thermal conductivity. In terms of flame retardant modification, traditional halogenated flame retardants have high flame retardant efficiency, but they release toxic and corrosive gases when burning. On the other hand, halogen-free flame retardants such as phosphorus-based ones generally have the problem of high addition amounts, and excessive addition will further deteriorate the low-temperature resistance of polyurethane foams.

[0004] In summary, the preparation of a cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks and its preparation process, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A process for preparing cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks includes the following steps: Step 1: Mix polyether polyol, hydroxyl-terminated polybutadiene, polysiloxane surfactant, catalyst, flame-retardant phenylphosphine-modified silicone oil, and deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy-modified silicone oil in a certain proportion to obtain component B; Step 2: Add component B to component A, mix evenly, pour into a mold for foaming and molding, and obtain cryogenic heat-insulating flame-retardant polyurethane foam.

[0007] In a more optimized form, the raw materials of component A include the following components: by mass parts, 40-60 parts of polyether polyol, 10-15 parts of hydroxyl-terminated polybutadiene, 0.5-0.8 parts of polysiloxane surfactant, 0.8-1 parts of catalyst, 15-20 parts of flame-retardant phenylphosphine-modified silicone oil, and 0.15-0.2 parts of deionized water; in component B, the mass ratio of 4,4'-diphenylmethane diisocyanate to bi-epoxy-terminated modified silicone oil is (6-8):1.

[0008] More optimally, the mass ratio of component A to component B is 20:(15~17).

[0009] The solution uses a mixture of high molecular weight polyether polyols and low molecular weight polyether polyols; the high molecular weight polyether polyol improves low-temperature toughness and thermal insulation; the low molecular weight polyether polyol reacts faster with isocyanate, which can increase the crosslinking density of the foam and improve compressive strength and hardness.

[0010] Polyether polyol, as the continuous phase in the preparation of polyurethane foam, reacts with isocyanate to form a three-dimensional cross-linked network; hydroxyl-terminated polybutadiene has certain flexibility and good cold resistance, and its addition can prevent polyurethane foam from becoming brittle under cryogenic conditions, with its terminal hydroxyl groups participating in cross-linking; polysiloxane surfactants improve the dispersion of polyether polyol, hydroxyl-terminated polybutadiene, and flame retardant, thereby enhancing the stability of polyurethane foam.

[0011] A more optimized method for preparing the dual-terminal epoxy-modified silicone oil is as follows: (1) 3-buten-1-ol and triethylamine are added to dichloromethane and mixed. Nitrogen gas is introduced, and under ice-water bath conditions, phenyl phosphorus dichloride-dichloromethane is added. The mixture is stirred at room temperature, filtered, concentrated, and purified to obtain di(but-3-en-1-yl)phenylphosphonite; (2) dual-terminal hydrogen-containing silicone oil PHMS and di(but-3-en-1-yl)phenylphosphonite are added to toluene and mixed. A catalyst is added, and under a nitrogen atmosphere, the temperature is raised to 100~110℃ and stirred for 25~35 minutes. Allyl glycidyl ether is added, and stirring is continued for 1~2 hours. The mixture is then distilled under reduced pressure to obtain the dual-terminal epoxy-modified silicone oil.

[0012] More optimized, the molar ratio of phenyl phosphorus dichloride to 3-buten-1-ol is (2~2.3):1; the raw materials of the dual-terminated epoxy modified silicone oil include the following components: by mass, 8~10 parts of dual-terminated hydrogen-containing silicone oil PHMS, 2~4 parts of di(but-3-en-1-yl)phenylphosphonite, 0.2~0.3 parts of catalyst, and 1~3 parts of allyl glycidyl ether.

[0013] In the scheme, under certain conditions, the hydroxyl group on 3-buten-1-ol reacts with the chlorine group on phenyl phosphorus dichloride to obtain di(but-3-en-1-yl)phenylphosphonite; the vinyl groups on di(but-3-en-1-yl)phenylphosphonite and allyl glycidyl ether react with Si-H on the bi-terminated hydrogen-containing silicone oil PHMS to obtain a bi-terminated epoxy-modified silicone oil.

[0014] The preparation method of the double-ended hydrogen-containing silicone oil PHMS in the scheme is as follows: Under a nitrogen atmosphere, 100-150 parts of octamethylcyclotetrasiloxane are mixed with concentrated sulfuric acid (concentration of 98%), heated to 55-60℃, and 22-25 parts of 1,1,3,3-tetramethyldisiloxane are added. The mixture is stirred and reacted for 10-12 hours, cooled to room temperature, allowed to stand and separated to obtain an oil phase. The oil phase is then treated sequentially with sodium 50-carbonate and anhydrous magnesium sulfate, filtered, and then subjected to vacuum distillation to remove low-boiling substances to obtain the double-ended hydrogen-containing silicone oil PHMS; parts are by weight.

[0015] A more optimized method for preparing the flame-retardant phenylphosphine-modified silicone oil is as follows: (1) Add the double-ended epoxy-modified silicone oil to DMF and mix, heat to 120~130℃, add DOPO and mix, heat to 140~150℃, stir for 2~4 hours, cool to room temperature, and obtain DOPO-modified epoxy-modified silicone oil; (2) Heat triglycidyl isocyanurate to 120~130℃, add DOPO and mix, heat to 140~150℃, stir for 2~4 hours, cool to 95~105℃, add DOPO modified epoxy-modified silicone oil and stir, add boric acid-DMF dropwise, continue stirring at 120~130℃ for 4~6 hours, cool to room temperature, wash and dry to obtain flame retardant phenylphosphine modified silicone oil.

[0016] In a more optimized manner, the mass ratio of the dual-terminated epoxy modified silicone oil to DOPO is 1:(0.1~0.25); in the flame-retardant phenylphosphine modified silicone oil, the molar ratio of triglycidyl isocyanurate, DOPO, DOPO-modified epoxy modified silicone oil, and boric acid is 1:1:2:2.

[0017] In this scheme, the epoxy groups on the double-ended epoxy modified silicone oil first undergo ring-opening addition with the pH on DOPO to generate DOPO-modified epoxy modified silicone oil; some of the epoxy groups of triglycidyl isocyanate react with DOPO, and then are mixed with DOPO-modified epoxy modified silicone oil, and boric acid is introduced. The boric acid and the epoxy groups in the system are cross-linked to obtain a flame-retardant phenylphosphine-modified silicone oil with a three-dimensional network.

[0018] The optimized foaming molding process conditions are as follows: pressure of 120~150 bar, temperature of 50~60℃, pressure holding time of 100~130 seconds, heat holding time of 1~2 hours, and room temperature for 20~24 hours.

[0019] Compared with the prior art, the beneficial effects of the present invention are: In this scheme, polyether polyol, hydroxyl-terminated polybutadiene, polysiloxane surfactant, catalyst, flame retardant, and deionized water are mixed as component A; 4,4'-diphenylmethane diisocyanate and double-terminated epoxy modified silicone oil are mixed in a certain proportion as component B; component B and component A are mixed and foamed to obtain cryogenic thermal insulation flame retardant polyurethane foam.

[0020] In this scheme, polyether polyol serves as the main backbone, and its hydroxyl groups react with isocyanate to form polyurethane foam with a three-dimensional network structure. Hydroxyl-terminated polybutadiene has good low-temperature resistance, and its hydroxyl groups can participate in the reaction to introduce flexible segments into the polyurethane network, thereby improving the polyurethane foam's ability to prevent brittle fracture at low temperatures. Meanwhile, polysiloxane surfactants can reduce the interfacial tension between components and improve the compatibility between raw materials.

[0021] In component B, 4,4'-diphenylmethane diisocyanate provides a rigid benzene ring structure, improving the stability of polyurethane foam; the introduction of bi-epoxy modified silicone oil can improve water absorption and low-temperature resistance, and also has certain flame retardancy; in the scheme, bis(but-3-en-1-yl)phenylphosphonite is prepared from phenylphosphine dichloride and 3-buten-1-ol, and then undergoes an addition reaction with bis(but-3-en-1-yl)phenylphosphonite and allyl glycidyl ether to prepare a bi-epoxy modified silicone oil with low-temperature resistance and certain flame retardancy.

[0022] To improve the flame retardancy of polyurethane foam, DOPO is introduced as a flame retardant. However, studies have found that direct addition reduces the low-temperature resistance and strength of polyurethane foam, affecting its application in LNG storage tanks. To address this issue, a dual-terminated epoxy-modified silicone oil with certain flame retardancy is used as a base. Under certain conditions, DOPO, triglycidyl isocyanate, and boric acid are introduced to obtain a flame-retardant phenylphosphine-modified silicone oil, which is beneficial for improving the flame retardancy and low-temperature resistance of polyurethane foam. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following specific embodiments, the parts are by weight. In this embodiment, it should be noted that there are no special restrictions on the purchase manufacturers of all the raw materials involved in this invention. Exemplary examples include: phenyl phosphorus dichloride CAS number 644-97-3; 3-buten-1-ol CAS number 627-27-0; triethylamine CAS number 121-44-8; DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) CAS number 35948-25-5; triglycidyl isocyanate CAS number 2451-62-9; boric acid CAS number 10043-35-3; 4,4'-diphenylmethane diisocyanate CAS number 101-68-8; hydroxyl-terminated polybutadiene CAS number ZS-11116; and polysiloxane surfactant AK8805.

[0025] Example 1: A process for preparing cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks, comprising the following steps: Pre-preparation: The preparation method of the double-terminated epoxy modified silicone oil is as follows: (1) Phenylene dichloride and 3-buten-1-ol are weighed in a molar ratio of 2.2:1; 3-buten-1-ol and triethylamine (the amount of triethylamine added is 2.0 times the molar amount of phenyl dichloride) are added to dichloromethane and mixed. Nitrogen gas is introduced, and under ice-water bath conditions, phenyl dichloride-dichloromethane is added. The mixture is stirred at room temperature, filtered and concentrated, and purified to obtain di(but-3-en-1-yl)phenylphosphine ester; (2) 9 parts of double-terminated hydrogen-containing silicone oil PHMS and 2 parts of di(but-3-en-1-yl)phenylphosphine ester are added to toluene and mixed. 0.25 parts of catalyst (Karstedt catalyst) are added. Under nitrogen atmosphere, the temperature is raised to 100℃ and stirred for 30 hours. 2 parts of allyl glycidyl ether are added and stirred for 1.5 hours. The mixture is then distilled under reduced pressure to obtain the double-terminated epoxy modified silicone oil; The preparation method of flame-retardant phenylphosphine-modified silicone oil is as follows: (1) Add the double-terminated epoxy-modified silicone oil to DMF and mix, heat to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to room temperature, and obtain DOPO-modified epoxy-modified silicone oil; wherein, the mass ratio of double-terminated epoxy-modified silicone oil to DOPO is 1:0.2; (2) Heat the triglycidyl isocyanurate to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to 100°C, add DOPO-modified epoxy-modified silicone oil and stir, add boric acid-DMF dropwise, continue stirring at 125°C for 5 hours, cool to room temperature, wash, and dry to obtain flame-retardant phenylphosphine-modified silicone oil; the molar ratio of triglycidyl isocyanurate, DOPO, DOPO-modified epoxy-modified silicone oil, and boric acid is 1:1:2:2; Step 1: Mix 40 parts of polyether polyol (30 parts of polyether polyol with a molecular weight of 6000 and 10 parts of polyether polyol with a molecular weight of 2000), 10 parts of hydroxyl-terminated polybutadiene, 0.5 parts of polysiloxane surfactant, 1 part of catalyst (the mass ratio of triethylenediamine to 1,8-diazabicyclo-5,4,0-undec-7-ene is 1:0.3), 15 parts of flame-retardant phenylphosphine-modified silicone oil, and 0.15 parts of deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy-modified silicone oil at a mass ratio of 7:1 to obtain component B; Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam. The foaming molding process conditions are as follows: pressure of 120 bar, temperature of 60℃, pressure holding time of 110 seconds, heat holding time of 1 hour, and room temperature for 22 hours.

[0026] Example 2: A preparation process for cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks, comprising the following steps: Pre-preparation: The preparation method of the double-terminated epoxy modified silicone oil is as follows: (1) Phenylene dichloride and 3-buten-1-ol are weighed in a molar ratio of 2.2:1; 3-buten-1-ol and triethylamine (the amount of triethylamine added is 2.0 times the molar amount of phenyl dichloride) are added to dichloromethane and mixed. Nitrogen gas is introduced, and under ice-water bath conditions, phenyl dichloride-dichloromethane is added. The mixture is stirred at room temperature, filtered and concentrated, and purified to obtain di(but-3-en-1-yl)phenylphosphine ester; (2) 9 parts of double-terminated hydrogen-containing silicone oil PHMS and 2 parts of di(but-3-en-1-yl)phenylphosphine ester are added to toluene and mixed. 0.25 parts of catalyst (Karstedt catalyst) are added. Under nitrogen atmosphere, the temperature is raised to 100℃ and stirred for 30 hours. 2 parts of allyl glycidyl ether are added and stirred for 1.5 hours. The mixture is then distilled under reduced pressure to obtain the double-terminated epoxy modified silicone oil; The preparation method of flame-retardant phenylphosphine-modified silicone oil is as follows: (1) Add the double-terminated epoxy-modified silicone oil to DMF and mix, heat to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to room temperature, and obtain DOPO-modified epoxy-modified silicone oil; wherein, the mass ratio of double-terminated epoxy-modified silicone oil to DOPO is 1:0.2; (2) Heat the triglycidyl isocyanurate to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to 100°C, add DOPO-modified epoxy-modified silicone oil and stir, add boric acid-DMF dropwise, continue stirring at 125°C for 5 hours, cool to room temperature, wash, and dry to obtain flame-retardant phenylphosphine-modified silicone oil; the molar ratio of triglycidyl isocyanurate, DOPO, DOPO-modified epoxy-modified silicone oil, and boric acid is 1:1:2:2; Step 1: Mix 50 parts of polyether polyol (40 parts of polyether polyol with a molecular weight of 6000 and 10 parts of polyether polyol with a molecular weight of 2000), 15 parts of hydroxyl-terminated polybutadiene, 0.7 parts of polysiloxane surfactant, 1 part of catalyst (the mass ratio of triethylenediamine to 1,8-diazabicyclo-5,4,0-undec-7-ene is 1:0.3), 17 parts of flame-retardant phenylphosphine-modified silicone oil, and 0.17 parts of deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy-modified silicone oil at a mass ratio of 7:1 to obtain component B; Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam. The foaming molding process conditions are as follows: pressure of 120 bar, temperature of 60℃, pressure holding time of 110 seconds, heat holding time of 1 hour, and room temperature for 22 hours.

[0027] Example 3: A preparation process for cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks, comprising the following steps: Pre-preparation: The preparation method of the double-terminated epoxy modified silicone oil is as follows: (1) Phenylene dichloride and 3-buten-1-ol are weighed in a molar ratio of 2.2:1; 3-buten-1-ol and triethylamine (the amount of triethylamine added is 2.0 times the molar amount of phenyl dichloride) are added to dichloromethane and mixed. Nitrogen gas is introduced, and under ice-water bath conditions, phenyl dichloride-dichloromethane is added. The mixture is stirred at room temperature, filtered and concentrated, and purified to obtain di(but-3-en-1-yl)phenylphosphine ester; (2) 9 parts of double-terminated hydrogen-containing silicone oil PHMS and 2 parts of di(but-3-en-1-yl)phenylphosphine ester are added to toluene and mixed. 0.25 parts of catalyst (Karstedt catalyst) are added. Under nitrogen atmosphere, the temperature is raised to 100℃ and stirred for 30 hours. 2 parts of allyl glycidyl ether are added and stirred for 1.5 hours. The mixture is then distilled under reduced pressure to obtain the double-terminated epoxy modified silicone oil; The preparation method of flame-retardant phenylphosphine-modified silicone oil is as follows: (1) Add the double-terminated epoxy-modified silicone oil to DMF and mix, heat to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to room temperature, and obtain DOPO-modified epoxy-modified silicone oil; wherein, the mass ratio of double-terminated epoxy-modified silicone oil to DOPO is 1:0.2; (2) Heat the triglycidyl isocyanurate to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to 100°C, add DOPO-modified epoxy-modified silicone oil and stir, add boric acid-DMF dropwise, continue stirring at 125°C for 5 hours, cool to room temperature, wash, and dry to obtain flame-retardant phenylphosphine-modified silicone oil; the molar ratio of triglycidyl isocyanurate, DOPO, DOPO-modified epoxy-modified silicone oil, and boric acid is 1:1:2:2; Step 1: Mix 60 parts of polyether polyol (54 parts of polyether polyol with a molecular weight of 6000 and 6 parts of polyether polyol with a molecular weight of 2000), 15 parts of hydroxyl-terminated polybutadiene, 0.7 parts of polysiloxane surfactant, 1 part of catalyst (the mass ratio of triethylenediamine to 1,8-diazabicyclo-5,4,0-undec-7-ene is 1:0.3), 20 parts of flame-retardant phenylphosphine-modified silicone oil, and 0.2 parts of deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy-modified silicone oil at a mass ratio of 7:1 to obtain component B; Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam. The foaming molding process conditions are as follows: pressure of 120 bar, temperature of 60℃, pressure holding time of 110 seconds, heat holding time of 1 hour, and room temperature for 22 hours.

[0028] Comparative Example 1 is based on Example 3, but without the introduction of di(but-3-en-1-yl)phenylphosphonite, and the rest of the operation is the same; Pre-preparation: The preparation method of the double-epoxy modified silicone oil is as follows: 9 parts of double-hydrogen-containing silicone oil PHMS are added to toluene and mixed, 0.25 parts of catalyst are added, the temperature is raised to 100℃ under nitrogen atmosphere, and the mixture is stirred for 30 hours. 2 parts of allyl glycidyl ether are added, and the mixture is stirred for another 1.5 hours. The mixture is then distilled under reduced pressure to obtain the double-epoxy modified silicone oil. The preparation method of flame-retardant phenylphosphine-modified silicone oil is as follows: (1) Add the double-terminated epoxy-modified silicone oil to DMF and mix, heat to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to room temperature, and obtain DOPO-modified epoxy-modified silicone oil; wherein, the mass ratio of double-terminated epoxy-modified silicone oil to DOPO is 1:0.2; (2) Heat the triglycidyl isocyanurate to 125°C, add DOPO and mix, heat to 140°C, stir for 3 hours, cool to 100°C, add DOPO-modified epoxy-modified silicone oil and stir, add boric acid-DMF dropwise, continue stirring at 125°C for 5 hours, cool to room temperature, wash, and dry to obtain flame-retardant phenylphosphine-modified silicone oil; the molar ratio of triglycidyl isocyanurate, DOPO, DOPO-modified epoxy-modified silicone oil, and boric acid is 1:1:2:2; Step 1: Mix 60 parts of polyether polyol, 15 parts of hydroxyl-terminated polybutadiene, 0.7 parts of polysiloxane surfactant, 1 part of catalyst, 20 parts of flame-retardant phenylphosphine-modified silicone oil, and 0.2 parts of deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy-modified silicone oil at a mass ratio of 7:1 to obtain component B; Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam.

[0029] Comparative Example 2 is based on Example 3, but without the introduction of dual-terminal epoxy-modified silicone oil; the remaining operation steps are the same. Pre-preparation: The preparation method of boric acid-DOPO modified isocyanurate (flame retardant) is as follows: Triglycidyl isocyanurate is heated to 125℃, DOPO is added and mixed, the temperature is raised to 140℃ and stirred for 3 hours, then cooled to 100℃, boric acid-DMF is added dropwise, and stirring is continued at 125℃ for 5 hours. After cooling to room temperature, it is washed and dried to obtain boric acid-DOPO modified isocyanurate; the molar ratio of triglycidyl isocyanurate, DOPO and boric acid is 1:1:2. Step 1: Mix 60 parts of polyether polyol, 15 parts of hydroxyl-terminated polybutadiene, 0.7 parts of polysiloxane surfactant, 1 part of catalyst, 20 parts of boric acid-DOPO modified isocyanurate, and 0.2 parts of deionized water evenly to obtain component A; use 4,4'-diphenylmethane diisocyanate as component B. Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam.

[0030] Comparative Example 3 is based on Example 3, except that the flame-retardant phenylphosphine-modified silicone oil is replaced with DOPO, and the other operating steps are the same. Pre-preparation: The preparation method of the double-terminated epoxy modified silicone oil is as follows: (1) Phenylated phosphorus dichloride and 3-buten-1-ol are weighed in a molar ratio of 2.2:1; 3-buten-1-ol and triethylamine (the amount of triethylamine added is 2.0 times the molar amount of phenyl dichloride) are added to dichloromethane and mixed. Nitrogen gas is introduced, and under ice-water bath conditions, phenyl dichloride-dichloromethane is added. The mixture is stirred at room temperature, filtered and concentrated, and purified to obtain di(but-3-en-1-yl)phenylphosphine ester; (2) 9 parts of double-terminated hydrogen-containing silicone oil PHMS and 2 parts of di(but-3-en-1-yl)phenylphosphine ester are added to toluene and mixed. 0.25 parts of catalyst are added. Under nitrogen atmosphere, the temperature is raised to 100℃ and stirred for 30 hours. 2 parts of allyl glycidyl ether are added and stirred for 1.5 hours. The mixture is then distilled under reduced pressure to obtain the double-terminated epoxy modified silicone oil; Step 1: Mix 60 parts of polyether polyol, 15 parts of hydroxyl-terminated polybutadiene, 0.7 parts of polysiloxane surfactant, 1 part of catalyst, 20 parts of DOPO, and 0.2 parts of deionized water evenly to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-terminated epoxy modified silicone oil at a mass ratio of 7:1 to obtain component B; Step 2: Weigh component A and component B at a mass ratio of 20:15, add component B to component A, mix evenly, pour into a mold to foam and form, and obtain cryogenic heat-insulating flame-retardant polyurethane foam.

[0031] Test Experiment 1: Using a JF-3 oxygen index meter, the LOI values ​​of Examples 1-3 and Comparative Examples 1-3 were tested according to ASTM D2863 standard. The sample size of Examples 1-3 and Comparative Examples 1-3 was 100×6.5×3mm. 3 ; The cryogenic heat-insulating flame-retardant polyurethane foams prepared in Examples 1-3 and Comparative Examples 1-3 were immersed in liquid nitrogen (-163°C) for 12 hours, and the low-temperature dimensional stability (%) was tested. Table 1

[0032] Conclusions: Comparative Example 1, based on Example 3, did not introduce bis(but-3-en-1-yl)phenylphosphonite, resulting in a decrease in flame retardancy. However, the flame retardant and component B still contained silicone oil structures, so the impact on stability was relatively small. Comparative Example 2, based on Example 3, did not introduce bi-terminated epoxy-modified silicone oil, resulting in a decrease in the low-temperature resistance and flame retardancy of the polyurethane foam prepared in Comparative Example 2. Comparative Example 3, based on Example 3, replaced the flame-retardant phenylphosphine-modified silicone oil with DOPO, resulting in a decrease in flame retardancy and a deterioration in the dispersibility of DOPO, thus causing a decrease in the performance of Comparative Example 3.

[0033] Test Experiment 2: The compressive strength of Example 3 was tested according to GB / T8813-2008 standard; the thermal conductivity (mW / m·K) of Example 3 at 20℃ and -163℃ was tested according to ASTM C518 standard; the water absorption rate (%) of Example 3 was tested according to GB / T8810-2005 standard; and the density (kg / m³) of Example 3 was tested according to GB / T6343-2009 standard. 3 ).

[0034] Table 2

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A process for the preparation of cryogenic adiabatic flame retarded polyurethane foam for LNG storage tanks, characterized in that: The method comprises the following steps: Step 1: uniformly mix polyether polyol, hydroxyl-terminated polybutadiene, polysiloxane surfactant, catalyst, flame-retardant phosphine-modified silicone oil, and deionized water to obtain component A; mix 4,4'-diphenylmethane diisocyanate and double-end epoxy-modified silicone oil at a certain ratio to obtain component B; Step 2: add component B to component A, uniformly mix, and add to a mold to be foamed and molded to obtain deep cold insulation flame-retardant polyurethane foam. The preparation method of the double-end epoxy-modified silicone oil is as follows: (1) mix 3-buten-1-ol and triethylamine in dichloromethane, introduce nitrogen, add phenylphosphonic dichloride-dichloromethane under ice water bath condition, stir at room temperature, filter and concentrate, and purify to obtain di(but-3-en-1-yl)phenyl phosphite; (2) mix double-end hydrogen-containing silicone oil PHMS and di(but-3-en-1-yl)phenyl phosphite in toluene, add a catalyst, heat to 100-110 DEG C under nitrogen atmosphere, stir for 25-35 hours, add allyl glycidyl ether, continue to stir for 1-2 hours, and distill under reduced pressure to obtain double-end epoxy-modified silicone oil. The preparation method of the flame-retardant phosphine-modified silicone oil is as follows: (1) mix double-end epoxy-modified silicone oil in DMF, heat to 120-130 DEG C, add DOPO, heat to 140-150 DEG C, stir for 2-4 hours, and cool to room temperature to obtain DOPO-modified epoxy-modified silicone oil; (2) heat triallyl isocyanurate to 120-130 DEG C, add DOPO, heat to 140-150 DEG C, stir for 2-4 hours, cool to 95-105 DEG C, add DOPO-modified epoxy-modified silicone oil and stir, drop boronic acid-DMF, continue to stir at 120-130 DEG C for 4-6 hours, cool to room temperature, wash, and dry to obtain flame-retardant phosphine-modified silicone oil.

2. A process for the preparation of cryogenic adiabatic flame retarded polyurethane foam for LNG storage tank as claimed in claim 1, wherein: The raw materials of the component A include the following components: 40-60 parts of polyether polyol, 10-15 parts of hydroxyl-terminated polybutadiene, 0.5-0.8 parts of polysiloxane surfactant, 0.8-1 part of catalyst, 15-20 parts of flame-retardant phosphine-modified silicone oil, and 0.15-0.2 parts of deionized water; in the component B, the mass ratio of 4,4'-diphenylmethane diisocyanate to double-end epoxy-modified silicone oil is (6-8):

1.

3. The preparation process of cryogenic insulation and flame-retardant polyurethane foam for LNG storage tanks according to claim 1, characterized in that: The mass ratio of the component A to the component B is 20:(15-17).

4. The process for the preparation of cryogenic insulation and fire resistant polyurethane foam for LNG storage tank as claimed in claim 1, wherein: The molar ratio of the phenylphosphonic dichloride to 3-buten-1-ol is (2-2.3):1; the raw materials of the double-end epoxy-modified silicone oil include the following components: 8-10 parts of double-end hydrogen-containing silicone oil PHMS, 2-4 parts of di(but-3-en-1-yl)phenyl phosphite, 0.2-0.3 parts of catalyst, and 1-3 parts of allyl glycidyl ether.

5. The process for the preparation of cryogenic insulation and fire resistant polyurethane foam for LNG storage tank as claimed in claim 1, wherein: The mass ratio of the double-end epoxy modified silicone oil to DOPO is 1:(0.1-0.25); in the flame-retardant phenylphosphine modified silicone oil, the molar ratio of isocyanuric acid triglycidyl ester, DOPO, DOPO modified epoxy modified silicone oil and boric acid is 1:1:2:

2.

6. The process for the preparation of cryogenic insulation and fire resistant polyurethane foam for LNG storage tank as claimed in claim 1, wherein: The process conditions of the foaming molding are as follows: the pressure is 120-150 bar, the temperature is 50-60 DEG C, the pressure maintaining time is 100-130 seconds, the heat preservation time is 1-2 hours, and the room temperature standing time is 20-24 hours.

7. The preparation process of the cryogenic adiabatic flame-retardant polyurethane foam for LNG storage tanks according to any one of claims 1-6, wherein the cryogenic adiabatic flame-retardant polyurethane foam is prepared by the preparation process.

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