A room temperature curing water resistant polyurethane adhesive and a method for preparing the same

Abstract

The application discloses a room temperature curing water-resistant polyurethane adhesive and a preparation method thereof. The room temperature curing water-resistant polyurethane adhesive is composed of component A and component B, and the mass ratio of the component A to the component B is 100:8-30. The component A comprises hydroxyl-terminated polybutadiene, polyether polyol and isocyanate; the component B comprises aliphatic triol, polyether polyol, hydrophobic chain extender and catalyst. The water-resistant polyurethane adhesive provided by the application can be cured at room temperature, has good water-resistant sealing property, very low water vapor transmission rate and water absorption rate, good mechanical property, has excellent adhesion to various metal or non-metal substrates, and can be used for water-resistant sealing and adhesion or repair of strategic and tactical weapon models.

Description

Technical Field

[0001] This invention belongs to the field of materials and process technology, and relates to a room temperature curing water-resistant polyurethane adhesive and its preparation method. Background Technology

[0002] During the assembly of various strategic and tactical weapon models, many connection parts have high requirements for water-resistant sealing. For example, the bonding of the breathable membrane of the water-cooling system to the metal shell, the connection of the air inlet opening device, and the sealing of the electrical connector port. These parts must be protected by water-resistant sealing to prevent the effects of rain (ice) water, water vapor, and salt spray corrosion, so as to ensure the stable performance and reliable operation of the equipment and facilities.

[0003] Currently, commonly used water-resistant sealant adhesives mainly include silicone rubber adhesives, polyether polyurethane adhesives, polyester polyurethane adhesives, and polysulfide rubber sealants. However, with the continuous development of weapon models, the service environment of water-resistant sealant adhesives has become increasingly demanding. The water resistance, water vapor permeability, sealing performance, and bonding performance of traditional water-resistant sealants are no longer sufficient to meet the technical requirements of current models.

[0004] Therefore, in response to the water-resistant sealing requirements of various equipment and facilities, it is proposed to develop a room-temperature curing water-resistant polyurethane adhesive to meet the requirements of good water resistance, low water permeability, good sealing performance, fast room-temperature curing, low curing stress, excellent adhesion performance, and convenient construction, so as to ensure the normal operation of equipment and facilities. Summary of the Invention

[0005] The technical problem to be solved by this invention is that, given the current situation where the water resistance, water vapor permeability, sealing performance, and adhesive performance of traditional water-resistant sealants are insufficient to meet the water-resistant sealing requirements of various equipment and facilities in the current models, a room-temperature curing water-resistant sealant with superior water resistance, lower water permeability, better sealing performance, and higher adhesive strength can be obtained through the design and preparation of the material structure.

[0006] This invention provides a room-temperature curing, water-resistant polyurethane adhesive and its preparation method. The room-temperature curing, water-resistant polyurethane adhesive provided by this invention can be used on different substrates in conjunction with different surface treatment methods.

[0007] The room temperature curing water-resistant polyurethane adhesive provided by the present invention is composed of component A and component B;

[0008] The mass ratio of component A to component B is 100:8 to 30; specifically, it can be 100:21 to 23.

[0009] Component A comprises the following raw materials in parts by weight: 170-380 parts of hydroxyl-terminated polybutadiene, 10-30 parts of polyether polyol, and 100 parts of isocyanate.

[0010] Specifically, the weight percentage of the hydroxyl-terminated polybutadiene can be 240, 270, or 300 parts; the weight percentage of the polyether polyol can be 15 or 25 parts.

[0011] Component B comprises the following raw materials in parts by weight: 30-100 parts aliphatic triol, 30-200 parts polyether polyol, 20-100 parts hydrophobic chain extender, and 0.01-0.2 parts catalyst.

[0012] Specifically, the aliphatic triol can be 50 or 60 parts by weight; the polyether polyol can be 50, 100 or 160 parts by weight; the hydrophobic chain extender can be 40 parts by weight; and the catalyst can be 0.05 parts by weight.

[0013] The hydroxyl-terminated polybutadiene is a low-functionality specialty hydroxyl-terminated polybutadiene.

[0014] The hydrophobic chain extender is a diol or siloxane containing silicon or fluorine.

[0015] In the above-mentioned room temperature curing water-resistant polyurethane adhesive, the low-functionality special hydroxyl-terminated polybutadiene is a type II hydroxyl-terminated polybutadiene with a hydroxyl value of 0.54-0.64 mmol / g (specifically 0.59) and a number-average molecular weight of 2000-4300 (specifically 3180) or a type III hydroxyl-terminated polybutadiene with a hydroxyl value of 0.65-0.70 (specifically 0.67) mmol / g and a number-average molecular weight of 1800-3500 (specifically 2560).

[0016] The polyether polyols are selected from at least one of the following: polypropylene glycol with a number average molecular weight of 400-2000 (specifically 1000), polyethylene glycol with a number average molecular weight of 400-2000 (specifically 500-1000), and polytetramethylene glycol with a number average molecular weight of 400-1500 (specifically 650-1000).

[0017] The isocyanate is selected from at least one of 4,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0018] The aliphatic triol is selected from at least one of trimethylolpropane, glycerol, triethanolamine, and triisopropanolamine.

[0019] The hydrophobic chain extender is selected from at least one of hydroxypropyl-terminated polydimethylsiloxane, hydroxyl-terminated methyl-3,3,3-trifluoropropylsiloxane, 2,2,3,3-tetrafluoro-1,4-butanediol, and 2,3,5,6-tetrafluoro-1,4-benzyldiethanol.

[0020] The catalyst is selected from at least one of tertiary amine catalysts, organotin catalysts, and organozinc catalysts.

[0021] The method for preparing the room temperature curing water-resistant polyurethane adhesive provided by the present invention includes:

[0022] 1) Preparation of component A:

[0023] The hydroxyl-terminated polybutadiene and polyether polyol were added to a three-necked flask in a certain proportion, and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; then the temperature was lowered to 40℃~60℃, the isocyanate was added, and the reaction temperature was maintained at 70℃~85℃ for 2~3 hours until the isocyanate content of the component (the isocyanate content was determined according to GB / T12009.4-1989) was 3.5~7.5%; the mixture was then cooled to room temperature to obtain component A.

[0024] 2) Preparation of component B:

[0025] The aliphatic triol, polyether polyol, and hydrophobic chain extender were added to a three-necked flask in proportion, and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; the temperature was lowered to 40℃~60℃, the catalyst was added, and the mixture was stirred for 30 minutes~40 minutes; the mixture was then cooled to room temperature to obtain component B.

[0026] 3) The components A and B are packaged separately at a mass ratio of 100:8 to 30 to obtain the room temperature curing water-resistant polyurethane adhesive.

[0027] The application of the room temperature curing water-resistant polyurethane adhesive provided by the present invention in bonding or repair is also within the scope of protection of the present invention.

[0028] Specifically, the bonding includes:

[0029] After mixing components A and B evenly according to the ratio, the mixture is applied to the surface of material A and material B to be bonded. Then, the bonding surfaces of material A and material B are joined together and cured at room temperature for more than 24 hours under pressure to complete the bonding.

[0030] Materials A and B are both selected from at least one of aluminum, steel, copper, titanium alloy, chloroprene rubber, and cross-linked polyethylene.

[0031] The beneficial effects of this invention compared to the prior art are as follows:

[0032] 1) This invention uses hydroxyl-terminated polybutadiene as the main raw material to synthesize polyurethane prepolymer, which is beneficial to make the adhesive have a lower water absorption rate and water vapor permeability.

[0033] 2) By using a hydrophobic chain extender, the present invention makes it more difficult for water molecules to contact the polyurethane molecular chain, which is beneficial to further reduce the water absorption rate and water vapor transmission rate.

[0034] 3) The water-resistant polyurethane adhesive provided by this invention can be cured at room temperature, and the operating time can be adjusted according to the amount of catalyst.

[0035] 4) The water-resistant polyurethane adhesive provided by this invention has good water resistance and sealing properties and extremely low water vapor transmission rate, with a water vapor transmission rate ≤0.6g / m³. 2 24h;

[0036] 5) The water absorption rate of the water-resistant polyurethane adhesive provided by this invention is ≤0.5%;

[0037] 6) The ultra-low temperature resistant epoxy adhesive provided by this invention has good mechanical properties and excellent adhesion to a variety of metal or non-metal substrates. For example, it can be used for bonding metals such as aluminum, steel, copper, and titanium alloys, as well as non-metallic materials such as chloroprene rubber and cross-linked polyethylene. It can be used for water-resistant sealing bonding or repair of strategic and tactical weapon models. Detailed Implementation

[0038] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Unless otherwise specified, the methods described are conventional methods. Unless otherwise specified, the raw materials can be obtained from publicly available commercial sources. Obviously, the described embodiments are only a part of the embodiments of the invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0039] Example 1

[0040] (1) Preparation of component A: 300g of type III hydroxyl-terminated polybutadiene with a hydroxyl value of 0.67mmol / g and a number-average molecular weight of 2560 and 15g of polypropylene glycol with a number-average molecular weight of 1000 were added to a three-necked flask and dehydrated under vacuum at 90℃~110℃ until the moisture content was <0.03%; then the temperature was lowered to 40℃~60℃, and 100g of carbodiimide-modified diphenylmethane diisocyanate was added. The reaction temperature of the system was maintained at 70℃~85℃ and the reaction time was 2 hours until the isocyanate content of the component was 3.6%; then the temperature was lowered to room temperature to obtain component A;

[0041] (2) Preparation of component B: 30g of trimethylolpropane, 50g of polypropylene glycol with a number average molecular weight of 400 and 40g of 2,2,3,3-tetrafluoro-1,4-butanediol were added to a three-necked flask and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; the temperature was lowered to 40℃~60℃, 0.05g of tertiary amine catalyst was added, and the mixture was stirred for 30 minutes; the temperature was then lowered to room temperature to obtain component B.

[0042] (3) Obtaining room temperature curing water-resistant polyurethane adhesive: Mix component A and component B evenly at a mass ratio of 100:8, and it can be used for bonding the corresponding parts.

[0043] All raw materials used in the examples were commercially available: hydroxyl-terminated polybutadiene, Type III, Luoyang Liming Chemical Research Institute; polypropylene oxide glycol, JQN-210, Nanjing Jinqi Chemical Group; carbodiimide-modified diphenylmethane diisocyanate, CDMDI-100L, Yantai Wanhua Chemical; trimethylolpropane, 30188526, Sinopharm Chemical Reagent Co., Ltd.; polypropylene oxide glycol, JQN-204, Nanjing Jinqi Chemical Group; 2,2,3,3-tetrafluoro-1,4-butanediol, TT229625G, Sinopharm Chemical Reagent Co., Ltd.; tertiary amine catalyst, XW02805792, Sinopharm Chemical Reagent Co., Ltd.

[0044] Example 2

[0045] (1) Preparation of component A: 270g of type III hydroxyl-terminated polybutadiene with a hydroxyl value of 0.67 and a number-average molecular weight of 2560 and 25g of polytetramethylene glycol with a number-average molecular weight of 1000 were added to a three-necked flask and dehydrated under vacuum at 90℃~110℃ until the moisture content was <0.03%; then the temperature was lowered to 40℃~60℃ and 100g of 4,4'-diphenylmethane diisocyanate was added. The reaction temperature of the system was maintained at 70℃~85℃ and the reaction time was 2 hours until the isocyanate content of the component was 6.2%; then the temperature was lowered to room temperature to obtain component A;

[0046] (2) Preparation of component B: 50g of trimethylolpropane, 160g of polytetramethylene glycol with a number average molecular weight of 650 and 20g of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol were added to a three-necked flask and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; the temperature was lowered to 40℃~60℃, 0.05g of organotin catalyst was added, and the mixture was stirred for 30 minutes; the mixture was then cooled to room temperature to obtain component B.

[0047] (3) Obtaining room temperature curing water-resistant polyurethane adhesive: Mix component A and component B evenly at a mass ratio of 100:23, and it can be used for bonding the corresponding parts.

[0048] All raw materials used in the examples were commercially available: hydroxyl-terminated polybutadiene, Type III, Luoyang Liming Chemical Research Institute; polytetramethylene glycol, 1000S, BASF Chemicals; 4,4'-diphenylmethane diisocyanate, MDI-100, Yantai Wanhua Chemicals; trimethylolpropane, 30188526, Sinopharm Chemical Reagent Co., Ltd.; polytetramethylene glycol, 650S, BASF Chemicals; 2,3,5,6-tetrafluoro-1,4-benzenedimethanol, XW923390763, Sinopharm Chemical Reagent Co., Ltd.; organotin catalyst, 80044627, Sinopharm Chemical Reagent Co., Ltd.

[0049] Example 3

[0050] (1) Preparation of component A: 240g of type II hydroxyl-terminated polybutadiene with a hydroxyl value of 0.59 and a number-average molecular weight of 3180 and 30g of polypropylene glycol with a number-average molecular weight of 1000 were added to a three-necked flask and dehydrated under vacuum at 90℃~110℃ until the moisture content was <0.03%; then the temperature was lowered to 40℃~60℃ and 100g of 4,4'-diphenylmethane diisocyanate was added. The reaction temperature of the system was maintained at 70℃~85℃ and the reaction time was 2 hours until the isocyanate content of the component was 6.9%; then the temperature was lowered to room temperature to obtain component A;

[0051] (2) Preparation of component B: 60g of glycerol, 100g of polypropylene glycol with a number average molecular weight of 500 and 40g of 2,2,3,3-tetrafluoro-1,4-butanediol were added to a three-necked flask and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; the temperature was lowered to 40℃~60℃, 0.05g of organotin catalyst was added, and the mixture was stirred for 30 minutes; the mixture was then cooled to room temperature to obtain component B.

[0052] (3) Obtaining room temperature curing water-resistant polyurethane adhesive: Mix component A and component B evenly at a mass ratio of 100:21, and it can be used for bonding the corresponding parts.

[0053] All raw materials used in the examples were commercially available: hydroxyl-terminated polybutadiene, Type II, Luoyang Liming Chemical Research Institute; polypropylene oxide glycol, JQN-210, Nanjing Jinqi Chemical Group; 4,4'-diphenylmethane diisocyanate, MDI-100, Yantai Wanhua Chemical; glycerol, 10010618, Sinopharm Chemical Reagent Co., Ltd.; polypropylene oxide glycol, JQN-204, Nanjing Jinqi Chemical Group; 2,2,3,3-tetrafluoro-1,4-butanediol, TT229625G, Sinopharm Chemical Reagent Co., Ltd.; organotin catalyst, 80044627, Sinopharm Chemical Reagent Co., Ltd.

[0054] Table 1. Test results of low-temperature resistant adhesives

[0055]

[0056] In Table 1, the detection methods for each test item are as follows:

[0057] Water vapor transmission rate: GB / T 1037-2021 Determination of water vapor transmission performance of plastic films and sheets by cup method with weight gain and weight loss;

[0058] Water absorption rate: GB / T 1034-2008 Determination of water absorption of plastics;

[0059] Hardness: GB / T 531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore Hardness);

[0060] Tensile strength and elongation at break: GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0061] Bond strength: GB / T 7124-2008 Determination of tensile shear strength of adhesives (rigid material to rigid material)

[0062] As shown in Table 1, the polyurethane adhesives obtained in the three examples all exhibit low water vapor transmission rate and water absorption rate. Comparatively, as the molecular weight of the terminal hydroxyl polybutadiene in the system increases, the water vapor transmission rate and water absorption rate of the material gradually decrease; similarly, as the proportion of fluorine in the system increases, the water vapor transmission rate and water absorption rate of the material gradually decrease. The polyurethane adhesives obtained in the three examples all exhibit good mechanical properties. Comparatively, as the crosslinking density or rigidity in the structure increases, the material hardness and tensile strength gradually increase, while the elongation gradually decreases. The polyurethane adhesives obtained in the three examples all show good bonding strength to aluminum.

Claims

1. A room temperature curing, water-resistant polyurethane adhesive, comprising component A and component B; The mass ratio of component A to component B is 100:8~30; Component A comprises the following raw materials in parts by weight: 170-380 parts of hydroxyl-terminated polybutadiene, 10-30 parts of polyether polyol, and 100 parts of isocyanate. Component B comprises the following raw materials in parts by weight: 30-100 parts aliphatic triol, 30-200 parts polyether polyol, 20-100 parts hydrophobic chain extender, and 0.01-0.2 parts catalyst. The hydroxyl-terminated polybutadiene is a low-functionality specialty hydroxyl-terminated polybutadiene; the low-functionality specialty hydroxyl-terminated polybutadiene is a type II hydroxyl-terminated polybutadiene with a hydroxyl value of 0.54~0.64 mmol / g and a number-average molecular weight of 2000~4300 or a type III hydroxyl-terminated polybutadiene with a hydroxyl value of 0.65~0.70 mmol / g and a number-average molecular weight of 1800~3500. The hydrophobic chain extender is a diol or siloxane containing silicon or fluorine; specifically, the hydrophobic chain extender is selected from at least one of hydroxypropyl-terminated polydimethylsiloxane, hydroxyl-terminated methyl-3,3,3-trifluoropropylsiloxane, 2,2,3,3-tetrafluoro-1,4-butanediol, and 2,3,5,6-tetrafluoro-1,4-benzenedimethanol.

2. The room temperature curing water-resistant polyurethane adhesive according to claim 1, characterized in that: The polyether polyols are selected from at least one of polypropylene glycol with a number average molecular weight of 400-2000, polyethylene glycol with a number average molecular weight of 400-2000, and polytetramethylene glycol with a number average molecular weight of 400-1500.

3. The room temperature curing water-resistant polyurethane adhesive according to any one of claims 1-2, characterized in that: The isocyanate is selected from at least one of 4,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

4. The room temperature curing water-resistant polyurethane adhesive according to claim 1, characterized in that: The aliphatic triol is selected from at least one of trimethylolpropane, glycerol, triethanolamine, and triisopropanolamine.

5. The room temperature curing water-resistant polyurethane adhesive according to claim 1, characterized in that: The catalyst is selected from at least one of tertiary amine catalysts, organotin catalysts, and organozinc catalysts.

6. A method for preparing the room temperature curing water-resistant polyurethane adhesive according to any one of claims 1-5, comprising: 1) Preparation of component A: The hydroxyl-terminated polybutadiene and polyether polyol were added to a three-necked flask in a certain proportion, and the mixture was dehydrated under vacuum at 90℃~110℃ until the moisture content was <0.03%; then the temperature was lowered to 40℃~60℃, the isocyanate was added, and the reaction temperature was maintained at 70℃~85℃ for 2~3 hours until the isocyanate content of the component was 3.5~7.5%; the mixture was then cooled to room temperature to obtain component A. 2) Preparation of component B: The aliphatic triol, polyether polyol, and hydrophobic chain extender were added to a three-necked flask in proportion, and the mixture was vacuum dehydrated at 90℃~110℃ until the moisture content was <0.03%; the temperature was lowered to 40℃~60℃, the catalyst was added, and the mixture was stirred for 30 minutes~40 minutes; the mixture was then cooled to room temperature to obtain component B. 3) The components A and B are packaged separately at a mass ratio of 100:8~30 to obtain the room temperature curing water-resistant polyurethane adhesive.

7. The use of the room temperature curing water-resistant polyurethane adhesive according to any one of claims 1-6 in bonding or repair.

8. The application of the room-temperature curing, water-resistant polyurethane adhesive according to claim 7 in bonding or repair, characterized in that: The bonding includes: After mixing components A and B evenly according to the ratio, the mixture is applied to the surface of material A and material B to be bonded. Then, the bonding surfaces of material A and material B are joined together and cured at room temperature for more than 24 hours under pressure to complete the bonding. Materials A and B are both selected from at least one of aluminum, steel, copper, titanium alloy, chloroprene rubber, and cross-linked polyethylene.

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