Ultralow-temperature high-bonding-strength single-component polyurethane composition and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane adhesives, and discloses an ultralow-temperature high-bonding-strength single-component polyurethane composition and a preparation method thereof.The ultralow-temperature high-bonding-strength single-component polyurethane composition is prepared from, by mass, 50%-60% of first isocyanate, 10%-20% of prepolymer, 10%-20% of inorganic filler, 0.5%-1% of catalyst, 1%-2% of defoaming agent, 5%-10% of solvent oil and 0.11%-0.2% of pigment; the first isocyanate is formed by mixing toluene diisocynate and isophorone diisocyanate, and the mass ratio of the toluene diisocynate to the isophorone diisocyanate is 1: (0.5-1.5). The ultralow-temperature high-bonding-strength single-component polyurethane composition disclosed by the invention is excellent in bonding strength under normal-temperature and low-temperature conditions and excellent in bonding performance under an ultralow-temperature environment (-150 DEG C), and can meet industrial standards.

Description

Technical Field

[0001] The present application relates to the technical field of polyurethane adhesives, and mainly to an ultra-low temperature high bonding strength single-component polyurethane composition and a preparation method thereof. Background Art

[0002] Liquefied natural gas (LNG) is called "flexible natural gas". As a clean energy source, the world's demand for it is increasing year by year. According to the Natural Gas 2023 Annual Report, the net import volume of LNG will reach 389 million tons in 2022, an increase of 4.5% compared with the import volume of 372 million tons in 2021. The growth in demand for LNG has driven the growth in the number of LNG transport ships and LNG storage tanks worldwide. In the transportation and storage of LNG, the temperature of LNG can be as low as -161.5℃, so there are higher requirements for the materials of its carrier, requiring the use of ultra-low temperature resistant component materials. Polyurethane compositions have excellent properties such as low temperature resistance and high bonding strength, and are widely used in the field of LNG transportation and storage technology.

[0003] Among them, the comparative document CN111234766B discloses a two-component polyurethane composition resistant to ultra-low temperature and thermal shock and its preparation method, which discloses that "the main agent of the polyurethane composition is prepared from raw materials including the following components in parts by weight: 30-50 parts of hydroxyl-terminated polyurethane prepolymer; 1-5 parts of polyether polyol B; 30-60 parts of filler; 0.5-4 parts of desiccant; 0.05-0.5 parts of adhesion promoter; the curing agent is prepared from raw materials including the following components in parts by weight: 30-50 parts of isocyanate; 20-40 parts of polyether polyol C; 10-20 parts of filler. The two-component polyurethane composition has excellent ultra-low temperature resistance and thermal shock performance. The present invention also discloses the preparation method and application of the two-component polyurethane composition." However, the bonding effect of this two-component polyurethane composition is not outstanding when used in normal temperature and ultra-low temperature environments.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of this application is to provide a one-component polyurethane composition with ultra-low temperature and high bonding strength and a preparation method thereof, aiming to provide a new polyurethane adhesive with excellent bonding strength under normal temperature and low temperature conditions, which can be used in the transportation or storage of liquefied natural gas, etc.

[0006] The technical solution of this application is as follows: An ultra-low temperature high bonding strength one-component polyurethane composition, wherein, by mass percentage, comprises the following components: The first isocyanate is 50%-60%, the prepolymer is 10%-20%, the inorganic filler is 10%-20%, the catalyst is 0.5%-1%, the defoaming agent is 1%-2%, the solvent oil is 5%~10%, and the pigment is 0.11%-0.2%; The prepolymer is prepared by prepolymerization of 1,4-butanediol and a second isocyanate.

[0007] The ultra-low temperature high bonding strength one-component polyurethane composition of the present application has excellent bonding strength under normal temperature and low temperature conditions, and has excellent bonding performance in an ultra-low temperature environment (-150°C), and can meet industry standards.

[0008] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of the toluene diisocyanate to the isophorone diisocyanate is 1:0.5-1.5; The first isocyanate and the second isocyanate are made from the same raw material.

[0009] In the present application, the first isocyanate and the second isocyanate are actually the same component. The first isocyanate and the second isocyanate are divided mainly to divide the isocyanate into two steps for curing, so as to improve the performance of the polyurethane composition.

[0010] In the ultra-low temperature high bonding strength one-component polyurethane composition, the inorganic filler is one or a combination of two or more of heavy calcium carbonate, silicon dioxide, titanium dioxide, and graphene.

[0011] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the inorganic filler is a combination of heavy calcium carbonate and another inorganic filler, and the weight ratio of the heavy calcium carbonate to the other inorganic filler is 1:0.1-0.2.

[0012] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the catalyst is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, dibutyltin oxide, dimethyltin glycolate, and bismuth isooctanoate.

[0013] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the defoaming agent is one or a combination of two or more of mineral oil, polyvinyl chloride powder, calcium oxide and calcium hydroxide.

[0014] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the pigment is one or a combination of two or more of phthalocyanine blue, phthalocyanine green, lemon yellow and coal black.

[0015] The ultra-low temperature high bonding strength one-component polyurethane composition, wherein the solvent oil is one or a combination of two or more of ethyl acetate, methyl benzoate, dichloromethane and petroleum ether.

[0016] A method for preparing the ultra-low temperature high bonding strength one-component polyurethane composition as described above, comprising the following steps: (1) Drying the 1,4-butanediol at 80-120° C. in a vacuum environment for 1-3 hours to remove water, adding the second isocyanate and molecular sieve after cooling, stirring and reacting for 0.5-1.5 hours at room temperature in a nitrogen environment, then heating to 60-100° C. and stirring for 1-3 hours, keeping the speed at 150 rpm throughout the process, and after the reaction is completed, sieving to remove the molecular sieve, cooling and sealing to obtain a prepolymer; (2) The inorganic filler is mixed evenly, and the mixed inorganic filler is added to the first isocyanate, and then the solvent oil, the catalyst, the defoaming agent, the pigment and the first isocyanate containing the inorganic filler are added to the prepolymer, and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition.

[0017] The method for preparing the ultra-low temperature high bonding strength one-component polyurethane composition, wherein the pressure in the vacuum environment is -0.1 MPa.

[0018] Beneficial effects: The ultra-low temperature high bonding strength one-component polyurethane composition of the present application has excellent bonding strength under normal temperature and low temperature conditions, and has excellent bonding performance under ultra-low temperature environment (-150°C), which can meet industry standards. Moreover, the curing conditions of the ultra-low temperature high bonding strength one-component polyurethane composition of the present application are simple, and curing can be achieved at room temperature, and the time to achieve full curing is about 24 hours. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 1 of the present application.

[0020] Figure 2 This is a graph showing the ultra-low temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 1 of the present application.

[0021] Figure 3 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 2 of the present application.

[0022] Figure 4 This is a graph showing the ultra-low temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 2 of the present application.

[0023] Figure 5 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 3 of the present application.

[0024] Figure 6 This is a graph showing the ultra-low temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Example 3 of the present application.

[0025] Figure 7 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 1 of the present application.

[0026] Figure 8 This is a graph showing the ultra-low temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 1 of the present application.

[0027] Fig. 9 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 2 of the present application.

[0028] Fig.10 This is a graph showing the test results of the ultra-low temperature tensile shear strength of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 2 of the present application.

[0029] Fig.11 This is a graph showing the room temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 3 of the present application.

[0030] Fig.12 This is a graph showing the ultra-low temperature tensile shear strength test results of the ultra-low temperature high bonding strength single-component polyurethane composition in Comparative Example 3 of the present application. DETAILED DESCRIPTION

[0031] The present application provides an ultra-low temperature high bonding strength one-component polyurethane composition and a preparation method thereof. To make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] The present application provides a one-component polyurethane composition with ultra-low temperature and high bonding strength, which comprises the following components by mass percentage: The first isocyanate is 50%-60%, the prepolymer is 10%-20%, the inorganic filler is 10%-20%, the catalyst is 0.5%-1%, the defoaming agent is 1%-2%, the solvent oil is 5%~10%, and the pigment is 0.11%-0.2%; The prepolymer is formed by prepolymerization of 1,4-butanediol and the second isocyanate; the mass ratio of 1,4-butanediol to the second isocyanate is 1:0.8-1.2; The first isocyanate is prepared by mixing toluene diisocyanate and isophorone diisocyanate, wherein the mass ratio of toluene diisocyanate to isophorone diisocyanate is 1:0.5-1.5; The first isocyanate and the second isocyanate are made from the same raw material.

[0033] In the present application, a specific isocyanate combination is used. The toluene group in toluene diisocyanate can improve the surface drying speed and strength of polyurethane. Isophorone diisocyanate IPDI is a cycloaliphatic isocyanate with excellent light resistance. Its two isocyanate groups have different reactivity that differs by about ten times, which is beneficial for the preparation of various prepolymers. 1,4-Butanediol acts as a chain extender, which essentially increases the molecular weight of the polymer and turns short-chain molecules into long-chain macromolecules. After the molecular weight increases, its mechanical properties, heat resistance, and wear resistance will all improve. Both of these isocyanates are aromatic isocyanates, containing aromatic ring structures, which can improve the strength of polyurethane itself. 1,4-Butanediol is a short straight chain structure, and the cross-linking structure density with the two isocyanates is higher, and the cross-linking network is tighter. In low temperature environments, it can improve the problems of polyurethane cracking and deformation, and synergistically improve the bonding performance of the polyurethane composition at low temperatures.

[0034] In the present application, the first isocyanate and the second isocyanate are actually the same component. The first isocyanate and the second isocyanate are divided mainly to divide the isocyanate into two steps of curing. The second isocyanate is first pre-cured with 1,4-butanediol to prepare a prepolymer, and the prepolymer is then mixed with the first isocyanate and other raw materials. This can improve the performance of the polyurethane composition, such as improving bonding strength, weather resistance, chemical resistance, heat resistance, and reducing brittleness, so that it can adapt to specific usage conditions.

[0035] The ultra-low temperature and high bonding strength one-component polyurethane composition of the present application is a one-component polyurethane composition. It does not need to adjust the proportion during use, which can avoid the influence of improper proportions on the effect of the polyurethane composition during construction, and at the same time, it can also save construction time. The ultra-low temperature and high bonding strength one-component polyurethane composition of the present application has excellent bonding strength under normal temperature and low temperature conditions, and has excellent bonding performance in ultra-low temperature environment (-150°C), which can meet industry standards. Moreover, the curing conditions of the ultra-low temperature and high bonding strength one-component polyurethane composition of the present application are simple, and curing can be achieved at room temperature, and the time to achieve full curing is about 24 hours.

[0036] Furthermore, the inorganic filler may be one or a combination of two or more of heavy calcium carbonate, silicon dioxide, titanium dioxide, and graphene.

[0037] Heavy calcium carbonate can reduce costs and improve the colloid cohesive strength. Therefore, preferably, the inorganic filler is a combination of heavy calcium carbonate and one other inorganic filler, and the weight ratio of heavy calcium carbonate to the other inorganic filler is preferably 1:0.1-0.2.

[0038] Furthermore, the catalyst is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, dibutyltin oxide, dimethyltin glycolate, and bismuth isooctanoate.

[0039] Furthermore, the defoaming agent is one or a combination of two or more of mineral oil, polyvinyl chloride powder, calcium oxide, calcium hydroxide, etc.

[0040] Furthermore, the pigment is one or a combination of two or more of phthalocyanine blue, phthalocyanine green, lemon yellow, coal black, etc.

[0041] Furthermore, the solvent oil is one or a combination of two or more of ethyl acetate, methyl benzoate, dichloromethane, petroleum ether, etc.

[0042] The present application also provides a method for preparing an ultra-low temperature high bonding strength one-component polyurethane composition, comprising the following steps: (1) 1,4-butanediol is placed in a three-necked flask, placed in a vacuum drying oven, dried at 80-120°C for 1-3 hours to remove water, and after cooling, the second isocyanate and molecular sieve are added, stirred and reacted for 0.5-1.5 hours at room temperature in a nitrogen environment, and then heated to 60-100°C and stirred for 1-3 hours, with the rotation speed maintained at 150 rpm throughout the process. After the reaction is completed, the molecular sieve is removed by sieving, and the prepolymer is cooled and sealed for storage to obtain a prepolymer; (2) The inorganic filler is mixed evenly, and the mixed inorganic filler is added to the first isocyanate, and then solvent oil, a catalyst, a defoaming agent, a pigment and the first isocyanate containing the inorganic filler are added to the prepolymer, and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0043] In step (1), the pressure in the vacuum environment is -0.1 MPa.

[0044] In step (1), after the 1,4-butanediol is cooled, the second isocyanate and the molecular sieve are added, stirred and mixed evenly at room temperature, and then heated to promote curing, so that the reaction is more uniform and mild.

[0045] The ultra-low temperature high bonding strength one-component polyurethane composition of the present application can be cured at room temperature, the operating period is about 10 minutes at 20°C, and it takes about 24 hours to reach full curing, and it can be used for bonding between steels. The ultra-low temperature high bonding strength one-component polyurethane composition of the present application has excellent bonding strength and ultra-low temperature resistance, can maintain good bonding performance in an environment of -150°C, and can be used in normal temperature and ultra-low temperature environments.

[0046] The present application is further described below through specific embodiments.

[0047] Embodiment 1 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 50%, the prepolymer is 20%, the inorganic filler is 20%, the catalyst is 0.6%, the defoaming agent is 1%, the pigment is 0.2% and the solvent oil is 8.2%.

[0048] The prepolymer is prepared by prepolymerization of 1,4-butanediol and the second isocyanate, and the mass ratio of 1,4-butanediol to the second isocyanate is specifically 1:1.1.

[0049] The first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of toluene diisocyanate to isophorone diisocyanate is 1: 1. The first isocyanate and the second isocyanate are made of the same raw material.

[0050] The inorganic filler is a mixture of heavy calcium carbonate and silicon dioxide, and the mass ratio of heavy calcium carbonate to silicon dioxide is 1:0.2.

[0051] The catalyst is dibutyltin dilaurate.

[0052] The defoamer is mineral oil.

[0053] The pigment is phthalocyanine blue.

[0054] The solvent oil is a mixture of ethyl acetate and methyl benzoate, and the mass ratio of ethyl acetate to methyl benzoate is 1:1.

[0055] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; Calcium carbonate and silica fillers are mixed evenly, the mixed inorganic filler is added to the first isocyanate, and then solvent oil, catalyst, defoaming agent, pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature and high bonding strength one-component polyurethane composition of the present application.

[0056] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to the smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. Four samples were selected to test the tensile shear strength of the polyurethane composition at room temperature according to GB / T 7124-2008. The test results are as follows: Figure 1 As shown in Figure 2, the average tensile shear strength at room temperature is 22.55 MPa. Four samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Figure 2. Figure 2 As shown, its average tensile shear strength is 20.89 MPa.

[0057] Embodiment 2 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 55%, the prepolymer is 15%, the inorganic filler is 20%, the catalyst is 0.5%, the defoaming agent is 2%, the pigment is 0.2% and the solvent oil is 7.3%.

[0058] The prepolymer is prepared by prepolymerization of 1,4-butanediol and the second isocyanate, and the mass ratio of 1,4-butanediol to the second isocyanate is specifically 1:1.1.

[0059] The first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of toluene diisocyanate to isophorone diisocyanate is 1:0.5. The first isocyanate and the second isocyanate are made of the same raw material.

[0060] The inorganic filler is a mixture of heavy calcium carbonate and titanium dioxide, and the mass ratio of heavy calcium carbonate to titanium dioxide is 1:0.1.

[0061] The catalyst is stannous octoate.

[0062] The defoaming agent is polyvinyl chloride powder.

[0063] The pigment is phthalocyanine green.

[0064] The solvent oil is a mixture of methyl benzoate and dichloromethane, and the mass ratio of methyl benzoate to dichloromethane is 1:0.2.

[0065] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; The heavy calcium carbonate and titanium dioxide filler are mixed evenly, the first isocyanate is added to the mixed inorganic filler, and then solvent oil, catalyst, defoaming agent, pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0066] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to the smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. Three samples were selected to test the tensile shear strength of the polyurethane composition at room temperature according to GB / T 7124-2008. The test results are as follows: Figure 3 As shown in Figure 2, the average tensile shear strength at room temperature is 20.27 MPa. Two samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Figure 2. Figure 4 As shown, its average tensile shear strength is 27.42MPa.

[0067] Embodiment 3 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 53%, the prepolymer is 17%, the inorganic filler is 20%, the catalyst is 0.8%, the defoaming agent is 1%, the pigment is 0.2% and the solvent oil is 8%.

[0068] The prepolymer is prepared by prepolymerization of 1,4-butanediol and the second isocyanate, and the mass ratio of 1,4-butanediol to the second isocyanate is specifically 1:1.1.

[0069] The first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of toluene diisocyanate to isophorone diisocyanate is 1:1.5. The first isocyanate and the second isocyanate are made of the same raw material.

[0070] The inorganic filler is a mixture of heavy calcium carbonate and graphene, and the mass ratio of heavy calcium carbonate to graphene is 1:0.15.

[0071] The catalyst is dibutyltin oxide.

[0072] The defoaming agent is a mixture of mineral oil and calcium oxide, and the mass ratio of mineral oil to calcium oxide is 1:0.01.

[0073] The pigment is a mixture of phthalocyanine green and lemon yellow, and the mass ratio of phthalocyanine green to lemon yellow is 1:1.

[0074] The solvent oil is a mixture of ethyl acetate and petroleum ether, and the mass ratio of ethyl acetate to petroleum ether is 1:0.5.

[0075] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; The heavy calcium carbonate and graphene filler are mixed evenly, the first isocyanate is added to the mixed inorganic filler, and then solvent oil, catalyst, defoaming agent, pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0076] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to the smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. Three samples were selected to test the tensile shear strength of the polyurethane composition at room temperature according to GB / T 7124-2008. The test results are as follows: Figure 5 As shown in Figure 2, the average tensile shear strength at room temperature is 26.97 MPa. Three samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Figure 2. Figure 6 As shown, its average tensile shear strength is 24.15MPa.

[0077] Comparative Example 1 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 50%, the prepolymer is 20%, the inorganic filler is 20%, the catalyst is 0.6%, the defoaming agent is 1%, the pigment is 0.2% and the solvent oil is 8.2%.

[0078] The prepolymer is prepared by prepolymerization of 1,4-butanediol and the second isocyanate; the usage ratio of 1,4-butanediol and the second isocyanate is 1:1.1.

[0079] The first isocyanate is toluene diisocyanate. The first isocyanate and the second isocyanate are made of the same raw material.

[0080] The inorganic filler is a mixture of heavy calcium carbonate and silicon dioxide, and the mass ratio of heavy calcium carbonate to silicon dioxide is 1:0.2.

[0081] The catalyst is dibutyltin diosilicate.

[0082] The defoamer is mineral oil.

[0083] The pigment is phthalocyanine blue.

[0084] The solvent oil is a mixture of ethyl acetate and methyl benzoate, and the mass ratio of ethyl acetate to methyl benzoate is 1:1.

[0085] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; The heavy calcium carbonate and the silica filler are mixed evenly, the mixed inorganic filler is added to the first isocyanate, and then the solvent oil, the catalyst, the defoaming agent, the pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0086] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to a smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. Three samples were selected to test the tensile shear strength of the polyurethane composition at room temperature according to GB / T 7124-2008. The test results are as follows: Figure 7 As shown in Figure 2, the average tensile shear strength at room temperature is 9.21 MPa. Three samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Figure 2. Figure 8 As shown, its average tensile shear strength is 5.99 MPa.

[0087] Comparative Example 2 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 50%, the prepolymer is 20%, the inorganic filler is 20%, the catalyst is 0.6%, the defoaming agent is 1%, the pigment is 0.2% and the solvent oil is 8.2%.

[0088] The prepolymer is formed by prepolymerization of 1,4-butanediol and the second isocyanate, and the mass ratio of 1,4-butanediol to the second isocyanate is specifically 1:1.1.

[0089] The first isocyanate is isophorone diisocyanate.

[0090] The first isocyanate and the second isocyanate are made from the same raw material.

[0091] The inorganic filler is a mixture of heavy calcium carbonate and silicon dioxide, and the mass ratio of heavy calcium carbonate to silicon dioxide is 1:0.2.

[0092] The catalyst is dibutyltin dilaurate.

[0093] The defoamer is mineral oil.

[0094] The pigment is phthalocyanine blue.

[0095] The solvent oil is a mixture of ethyl acetate and methyl benzoate, and the mass ratio of ethyl acetate to methyl benzoate is 1:1.

[0096] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; The heavy calcium carbonate and the silica filler are mixed evenly, the mixed inorganic filler is added to the first isocyanate, and then the solvent oil, the catalyst, the defoaming agent, the pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0097] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to a smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. Three samples were selected to test the tensile shear strength of the polyurethane composition at room temperature according to GB / T 7124-2008. The test results are as follows: Fig. 9 As shown, the average tensile shear strength at room temperature is 6.06MPa. Three samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Fig.10 As shown, its average tensile shear strength is 5.17 MPa.

[0098] Comparative Example 3 The ultra-low temperature high bonding strength one-component polyurethane composition of the present application comprises the following components by mass percentage: The first isocyanate is 50%, the prepolymer is 20%, the inorganic filler is 20%, the catalyst is 0.6%, the defoaming agent is 1%, the pigment is 0.2% and the solvent oil is 8.2%.

[0099] The prepolymer is formed by prepolymerization of 1,4-butanediol and the second isocyanate, and the mass ratio of 1,4-butanediol to the second isocyanate is specifically 1:1.1.

[0100] The first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of toluene diisocyanate to isophorone diisocyanate is 0.5:1.

[0101] The second isocyanate is isophorone diisocyanate.

[0102] The inorganic filler is a mixture of heavy calcium carbonate and silicon dioxide, and the mass ratio of heavy calcium carbonate to silicon dioxide is 1:0.2.

[0103] The catalyst is dibutyltin dilaurate.

[0104] The defoamer is mineral oil.

[0105] The pigment is phthalocyanine blue.

[0106] The solvent oil is a mixture of ethyl acetate and methyl benzoate, and the mass ratio of ethyl acetate to methyl benzoate is 1:1.

[0107] 1,4-Butanediol was placed in a three-necked flask, placed in a vacuum drying oven, dried at 100°C for 2h under vacuum environment (-0.1MPa) to remove water, and after cooling, the second isocyanate and molecular sieve were added, stirred and reacted for 0.5h under nitrogen environment and room temperature, and then heated to 80°C and stirred for 2h, with the rotation speed kept at 150rpm throughout the process. After the reaction was completed, the molecular sieve was removed by sieving, and the mixture was cooled and sealed for storage to obtain a prepolymer; The heavy calcium carbonate and the silica filler are mixed evenly, the mixed inorganic filler is added to the first isocyanate, and then the solvent oil, the catalyst, the defoaming agent, the pigment and the first isocyanate containing the inorganic filler are added to the prepared prepolymer and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition of the present application.

[0108] The prepared ultra-low temperature high bonding strength one-component polyurethane composition was evenly applied to the smooth tinplate sheet, and two tinplate sheets coated with adhesive were bonded together, with a bonding surface of about 15*20mm. A certain pressure was applied until it was completely cured at room temperature for 24 hours. The tensile shear strength of the polyurethane composition was tested at room temperature according to GB / T 7124-2008. The test results of 3 samples were selected as follows: Fig.11 As shown in Figure 2, the average tensile shear strength at room temperature is 10.34 MPa. Three samples were selected and placed in a liquid nitrogen environment (minus 150°C) for tensile shear tests. The test results are shown in Figure 2. Fig.12 As shown, its average tensile shear strength is 12.12 MPa.

[0109] It should be understood that the application of the present application is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description, and all these improvements and changes should fall within the scope of protection of the present application.

Claims

1. A one-component polyurethane composition with ultra-low temperature and high bonding strength, characterized in that: According to mass percentage, it includes the following components: The first isocyanate is 50%-60%, the prepolymer is 10%-20%, the inorganic filler is 10%-20%, the catalyst is 0.5%-1%, the defoaming agent is 1%-2%, the solvent oil is 5%~10%, and the pigment is 0.11%-0.2%; The prepolymer is prepared by prepolymerization of 1,4-butanediol and a second isocyanate.

2. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The first isocyanate is a mixture of toluene diisocyanate and isophorone diisocyanate, and the mass ratio of the toluene diisocyanate to the isophorone diisocyanate is 1:0.5-1.5; The first isocyanate and the second isocyanate are made from the same raw material.

3. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The inorganic filler is one or a combination of two or more of heavy calcium carbonate, silicon dioxide, titanium dioxide and graphene.

4. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 3, characterized in that: The inorganic filler is a combination of heavy calcium carbonate and another inorganic filler, and the weight ratio of the heavy calcium carbonate to the other inorganic filler is 1:0.1-0.

2.

5. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The catalyst is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, dibutyltin oxide, dimethyltin glycolate, and bismuth isooctanoate.

6. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The defoaming agent is one or a combination of two or more of mineral oil, polyvinyl chloride powder, calcium oxide and calcium hydroxide.

7. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The pigment is one or a combination of two or more of phthalocyanine blue, phthalocyanine green, lemon yellow and coal black.

8. The ultra-low temperature high bonding strength one-component polyurethane composition according to claim 1, characterized in that: The solvent oil is one or a combination of two or more of ethyl acetate, methyl benzoate, dichloromethane and petroleum ether.

9. A method for preparing the ultra-low temperature high bonding strength one-component polyurethane composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Drying the 1,4-butanediol at 80-120° C. in a vacuum environment for 1-3 hours to remove water, adding the second isocyanate and molecular sieve after cooling, stirring and reacting for 0.5-1.5 hours at room temperature in a nitrogen environment, then heating to 60-100° C. and stirring for 1-3 hours, keeping the speed at 150 rpm throughout the process, and after the reaction is completed, sieving to remove the molecular sieve, cooling and sealing to obtain a prepolymer; (2) The inorganic filler is mixed evenly, and the mixed inorganic filler is added to the first isocyanate, and then the solvent oil, the catalyst, the defoaming agent, the pigment and the first isocyanate containing the inorganic filler are added to the prepolymer, and mixed evenly to obtain the ultra-low temperature high bonding strength one-component polyurethane composition.

10. The method for preparing the ultra-low temperature high bonding strength one-component polyurethane composition according to claim 9, characterized in that: The pressure in the vacuum environment is -0.1 MPa.

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