A room temperature curing ultra-low temperature resistant adhesive for sandwich bottom

Abstract

This invention provides a room-temperature curing, ultra-low temperature resistant adhesive for sandwich structures with a common bottom. The adhesive consists of two components, A and B. Component A comprises bisphenol A epoxy resin, core-shell particle modified epoxy resin, polyurethane modified epoxy resin, reactive diluent, silane coupling agent, and filler. Component B comprises aliphatic amines, cycloaliphatic amines, and polyamide. This adhesive exhibits excellent bonding properties. After 24 hours of full curing at room temperature, the aluminum-aluminum tensile shear strength is ≥20 MPa at -196°C and ≥25 MPa at room temperature. After curing, it demonstrates good adhesion to various substrate surfaces, and under normal conditions, the metal-to-metal 90° peel strength in sandwich structures exceeds 40 N / mm. Furthermore, it is simple to manufacture, low in cost, and can be applied to the sandwich structure of rocket kerosene-liquid oxygen storage tanks, withstanding the extreme environmental conditions of ultra-low temperatures and large temperature differences associated with kerosene-liquid oxygen.

Description

Technical Field

[0001] This invention relates to a room temperature curing, ultra-low temperature resistant adhesive, specifically to a room temperature curing epoxy adhesive for use in rocket propellant tank sandwich common bottom structures that can withstand large temperature differences. Background Technology

[0002] Cryogenic adhesives primarily refer to adhesives that can be used in environments at -150℃ and below, especially those with sufficient bonding strength for use in environments such as liquid nitrogen (-196℃) and liquid oxygen (-183℃). A sandwich-type common-bottom structure refers to the intermediate sandwich structure of a rocket kerosene-liquid oxygen storage tank, with a significant temperature difference between its two ends (room temperature to -183℃). Therefore, requirements are placed on the adhesives used in sandwich-type common-bottom structures: on the one hand, the adhesive must possess excellent bonding performance to ensure sufficient bonding strength under both room temperature and cryogenic conditions; on the other hand, the adhesive must have a simple application process and be able to cure at room temperature. Currently used adhesives are specialized room-temperature curing cryogenic adhesives, but their disadvantages include high cost and a short operating window.

[0003] Epoxy resins contain polar epoxy groups, exhibiting excellent adhesive properties and are currently the most widely used and high-performing type of adhesive. However, epoxy resins are relatively brittle, a drawback that becomes more pronounced in ultra-low temperature environments, severely limiting their application range. Generally, the main factors affecting the bonding strength of epoxy adhesives at low temperatures include the epoxy resin, curing agent, toughening agent, and accelerator. Currently, to address the challenges of applying epoxy adhesives at low temperatures, toughening methods are commonly used to improve their bonding performance.

[0004] Therefore, this invention addresses the problem of ultra-low temperature adhesives for sandwich-type common bottoms with excellent comprehensive performance through in-depth research and multiple improvements, resulting in this invention. Summary of the Invention

[0005] This invention addresses the shortcomings of existing low-temperature resistant adhesives for sandwich panels, such as short working time and high price. To extend the working time of adhesives and reduce material costs, this invention provides a room-temperature curing, ultra-low-temperature resistant adhesive for sandwich panels.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] This invention relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, comprising component A and component B. Component A is composed of bisphenol A epoxy resin, core-shell particle modified epoxy resin, polyurethane modified epoxy resin, reactive diluent, silane coupling agent, and filler; component B is composed of aliphatic amines, cycloaliphatic amines, and polyamides.

[0008] This adhesive exhibits excellent bonding properties. After 24 hours of full curing at room temperature, the aluminum-aluminum tensile shear strength is ≥20MPa at -196℃ and ≥25MPa at room temperature. It is also simple to manufacture and inexpensive, and can be applied to the sandwich common bottom structure of rocket kerosene-liquid oxygen storage tanks, and can withstand the extreme environmental test of ultra-low temperature and large temperature difference brought by kerosene-liquid oxygen.

[0009] As one implementation, the mass ratio of component A to component B is 2:1.

[0010] As one implementation, based on the total mass of component A, component A comprises 30-50 wt% bisphenol A epoxy resin, 25-40 wt% core-shell modified epoxy resin, 5-20 wt% polyurethane modified epoxy resin, 5-20 wt% reactive diluent, 1-3 wt% silane coupling agent, and 5-10 wt% filler. In the system of this invention, bisphenol A epoxy resin provides the strength of the adhesive after curing; the core-shell modified epoxy resin can increase the viscosity of the adhesive, ensuring processability while improving the toughness of the adhesive; the polyurethane modified epoxy resin improves the low-temperature toughness of the adhesive by forming an interpenetrating network structure; the selection of 30-50 wt% bisphenol A epoxy resin, 25-40 wt% core-shell modified epoxy resin, and 5-20 wt% polyurethane modified epoxy resin allows the three to fully exert their synergistic effect, ensuring that the adhesive performs optimally.

[0011] As one implementation, based on the total mass of component B, component B consists of 10-30 wt% aliphatic amine, 55-80 wt% alicyclic amine, and 5-15 wt% polyamide. The adhesive of this invention is a room-temperature curing, low-temperature resistant adhesive. In the combined curing agent: the aliphatic amine ensures room-temperature curing and high curing strength, but also has a high reaction rate, short working time, and brittle cured product; the alicyclic amine, as a flexible curing agent, ensures the elasticity of the cured product while effectively extending the working time; the polyamide provides good interfacial adhesion properties. The range of the three components is a comprehensive selection to ensure the adhesive performs optimally; exceeding this range will lead to performance biased towards the components.

[0012] As one embodiment, the bisphenol A epoxy resin is one or more combinations of E42, E44, and E51.

[0013] As one implementation, the core-shell particle modified epoxy resin is one or more combinations of EPX-125, EPX-140, and EPX-152.

[0014] As one embodiment, the polyurethane-modified epoxy resin is one or more combinations of EPU-133, EPU-253, EPU-300, and EPU-307.

[0015] As one embodiment, the active diluent is one or more combinations of resorcinol diglycidyl ether, 1,4-butanediol diglycidyl ether, and ethylene glycol diglycidyl ether.

[0016] As one implementation, the silane coupling agent is at least one or a combination of KH550, KH560, and KH570.

[0017] As one embodiment, the filler is at least one or more combinations of fumed silica, glass microspheres, and nitrile rubber.

[0018] As one embodiment, the fatty amine is at least one or more of diethylenetriamine, triethylenetetramine, and 593#.

[0019] As one embodiment, the alicyclic amine is at least one or more of 1,3-BAC, 1010B, and AEP.

[0020] As one embodiment, the polyamide is one or more of 115#, 650#, and 651#.

[0021] Compared with existing technologies, the advantages of this invention are as follows:

[0022] 1) Compared with other low-temperature resistant adhesives, the room temperature curing and ultra-low temperature resistant adhesive for sandwich co-bottom of the present invention has a longer working time of 90 to 100 minutes at 25°C, and has good adhesion to the surface of various substrates after curing; under normal conditions, the metal-to-metal tensile shear strength at room temperature is ≥25MPa, and the metal-to-metal tensile shear strength at -196°C is ≥20MPa.

[0023] 2) The adhesive has a 90° peel strength greater than 40 N / mm and can withstand the extreme environment of ultra-low temperature and large temperature difference brought by kerosene-liquid oxygen.

[0024] 3) This adhesive has a relatively low overall cost compared to similar products, and has a high cost-performance ratio. Detailed Implementation

[0025] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0026] Example 1

[0027] This embodiment relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0028] (1) Preparation of component A:

[0029] ① Add 45 parts by weight of bisphenol A epoxy resin, 35 parts by weight of core-shell particle modified epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent to a high-speed stirring tank in sequence. Slowly accelerate the high-speed stirring to 1000 rpm and stir for 40 minutes before turning it off.

[0030] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it 5 times with a three-roll mill to obtain component A.

[0031] (2) Preparation of component B:

[0032] 25 parts by weight of fatty amine, 65 parts by weight of alicyclic amine and 10 parts by weight of polyamide were added to a mixing tank, the speed was slowly increased to 100 rpm, and the mixture was stirred for 5 minutes before being turned off to obtain component B.

[0033] Example 2

[0034] This embodiment relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0035] (1) Preparation of component A:

[0036] ① Add 35 parts by weight of bisphenol A epoxy resin, 45 parts by weight of core-shell particle modified epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent to a high-speed stirring tank in sequence. Slowly accelerate the high-speed stirring to 1500 rpm and stir for 35 minutes before turning it off.

[0037] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it 4 times with a three-roll mill to obtain component A.

[0038] (2) Preparation of component B:

[0039] 25 parts by weight of fatty amine, 65 parts by weight of alicyclic amine and 10 parts by weight of polyamide were added to a mixing tank, the speed was slowly increased to 90 rpm, and the mixture was stirred for 8 minutes before being turned off to obtain component B.

[0040] Example 3

[0041] This embodiment relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0042] (1) Preparation of component A:

[0043] ① Add 65 parts by weight of bisphenol A epoxy resin, 15 parts by weight of core-shell particle modified epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent into a high-speed stirring vessel in sequence. Slowly accelerate the high-speed stirring to 2000 rpm and stir for 30 minutes before turning it off.

[0044] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it three times with a three-roll mill to obtain component A.

[0045] (2) Preparation of component B:

[0046] 25 parts by weight of fatty amine, 65 parts by weight of alicyclic amine and 10 parts by weight of polyamide were added to a mixing tank, the speed was slowly increased to 80 rpm, and the mixture was stirred for 10 minutes before being turned off to obtain component B.

[0047] Example 4

[0048] This embodiment relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0049] (1) Preparation of component A:

[0050] ① Add 45 parts by weight of bisphenol A epoxy resin, 35 parts by weight of core-shell particle modified epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent to a high-speed stirring tank in sequence. Slowly accelerate the high-speed stirring to 1500 rpm and stir for 30 minutes before turning it off.

[0051] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it 4 times with a three-roll mill to obtain component A.

[0052] (2) Preparation of component B:

[0053] Add 30 parts by weight of fatty amine, 60 parts by weight of alicyclic amine and 10 parts by weight of polyamide to a mixing tank, slowly accelerate to 90 rpm, stir for 6 minutes and then stop to obtain component B.

[0054] Example 5

[0055] This embodiment relates to a room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0056] (1) Preparation of component A:

[0057] ① Add 45 parts by weight of bisphenol A epoxy resin, 35 parts by weight of core-shell particle modified epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent to a high-speed stirring tank in sequence. Slowly accelerate the high-speed stirring to 1500 rpm and stir for 40 minutes before turning it off.

[0058] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it 4 times with a three-roll mill to obtain component A.

[0059] (2) Preparation of component B:

[0060] 15 parts by weight of fatty amine, 75 parts by weight of alicyclic amine and 10 parts by weight of polyamide were added to a mixing tank, the speed was slowly increased to 85 rpm, and the mixture was stirred for 8 minutes before being turned off to obtain component B.

[0061] Comparative Example 1

[0062] This comparative example relates to an adhesive, the specific composition of which is shown in Table 1; the preparation steps are as follows:

[0063] (1) Preparation of component A:

[0064] ① Add 80 parts by weight of glycidyl ether type epoxy resin, 10 parts by weight of polyurethane modified epoxy resin, 10 parts by weight of reactive diluent, and 2 parts by weight of silane coupling agent sequentially into a high-speed stirred tank. Slowly increase the high-speed stirring to 1500 rpm and stir for 35 minutes, then turn off the stirring.

[0065] ② Add 5 parts by weight of filler to the homogeneous system in ①, and grind it 4 times with a three-roll mill to obtain component A.

[0066] (2) Preparation of component B:

[0067] Take 90 parts by weight of fatty amine and 10 parts by weight of polyamide, add them to a mixing tank, slowly accelerate to 90 rpm, stir for 8 minutes and then stop to obtain component B.

[0068] Table 1

[0069]

[0070]

[0071] Comparative Example 2

[0072] This comparative example is basically the same as Example 1, except that: the epoxy resin in component A is 40 parts by weight of E51 and 50 parts by weight of EPX-152, and there is no EPU-133.

[0073] Comparative Example 3

[0074] This comparative example is basically the same as Example 1, except that: in component B, the epoxy resin is 30 parts by weight of 593# and 70 parts by weight of 1010B, and there is no polyamide 115#.

[0075] The room temperature curing, ultra-low temperature resistant adhesives for sandwich co-bottoms obtained in Examples 1, 2, 3, 4, 5, and Comparative Example 1 of this invention were tested using the following methods:

[0076] Tensile shear strength test method: GB / T 7124-2012.

[0077] 90° peel strength test method: GJB 446-1998.

[0078] The test data is shown in Table 2 below:

[0079] Table 2

[0080] Test Project Room temperature tensile shear strength / MPa -196℃ tensile shear strength / MPa <![CDATA[90° peel strength / N·mm -1 > Experimental Example 1 30.78 26.52 47.58 Experiment Example 2 29.33 23.81 39.65 Experimental Example 3 35.46 21.67 30.56 Experiment Example 4 29.61 20.06 31.19 Experimental Example 5 28.67 28.93 32.08 Comparative Example 1 25.89 18.46 30.11 Comparative Example 2 27.79 18.05 32.36 Comparative Example 3 29.18 19.88 25.35

[0081] The results in the table above show that, with the synergistic effect of introducing core-shell particle modified epoxy resin, toughening agents such as fillers, and flexible curing agents, the room temperature / -196℃ tensile shear strength and 90° peel strength of the adhesive have been significantly improved.

[0082] In summary, the adhesive of this invention exhibits excellent adhesive properties. After full curing at room temperature for 24 hours, the aluminum-aluminum tensile shear strength is ≥20 MPa at -196°C and ≥25 MPa at room temperature. After curing, it demonstrates good adhesion to various substrate surfaces, and under normal circumstances, the metal-to-metal 90° peel strength in sandwich structures exceeds 40 N / mm. Furthermore, it is simple to manufacture and inexpensive, making it suitable for use in the sandwich common-bottom structure of rocket kerosene-liquid oxygen storage tanks, capable of withstanding the extreme environmental conditions of ultra-low temperatures and large temperature differences associated with kerosene-liquid oxygen.

[0083] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A room temperature curing, ultra-low temperature resistant adhesive for sandwich-type co-bottom applications, comprising component A and component B, characterized in that, Based on the mass percentage content of component A, component A consists of 30-50 wt% bisphenol A epoxy resin, 25-40 wt% core-shell particle modified epoxy resin, 5-20 wt% polyurethane modified epoxy resin, 5-20 wt% reactive diluent, 1-3 wt% silane coupling agent, and 5-10 wt% filler; wherein the polyurethane modified epoxy resin is one or more combinations of EPU-133, EPU-253, and EPU-307. Based on the mass percentage content of component B, component B consists of 10-30 wt% aliphatic amines, 55-80 wt% alicyclic amines, and 5-15 wt% polyamides; the aliphatic amines are at least one or more of diethylenetriamine, triethylenetetramine, and 593#. The mass ratio of component A to component B is 2:

1.

2. The room temperature curing, ultra-low temperature resistant adhesive for sandwich-type common bottom as described in claim 1, characterized in that, The bisphenol A epoxy resin is one or more combinations of E42, E44, and E51.

3. The room temperature curing, ultra-low temperature resistant adhesive for sandwich-type common bottoms according to claim 1, characterized in that, The core-shell particle modified epoxy resin is one or more combinations of EPX-125, EPX-140, and EPX-152.

4. The room temperature curing, ultra-low temperature resistant adhesive for sandwich-type common bottom as described in claim 1, characterized in that, The active diluent is one or more of resorcinol diglycidyl ether, 1,4-butanediol diglycidyl ether, and ethylene glycol diglycidyl ether; the silane coupling agent is at least one or more of KH550, KH560, and KH570; and the filler is at least one or more of fumed silica, 50# glass microspheres, and nitrile rubber.

5. The room temperature curing, ultra-low temperature resistant adhesive for sandwich-type common bottom as described in claim 1, characterized in that, The alicyclic amine is at least one or more of 1,3-BAC, 1010B, and AEP; the polyamide is one or more of 115#, 650#, and 651#.

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