Sealing material and preparation method and application thereof

Abstract

The invention provides a sealing material and a preparation method and application thereof, and belongs to the technical field of binders, the sealing material comprises an isocyanate prepolymer and a chain extender, the mass ratio of the isocyanate prepolymer to the chain extender is (130-268): 100; the isocyanate prepolymer is prepared from the following raw materials: an isocyanate monomer, hydroxyl-terminated fluorosilicone oil and castor oil modified polyol; the chain extender is prepared from the following raw materials: bio-based polyether polyol, a surface modifier, an anticorrosive filler, an anti-sagging thixotropic agent, a dewatering agent, a dispersing agent and a corrosion inhibitor. Hydroxyl fluorosilicone oil with excellent hydrophobicity and efficient lubricity is introduced to a molecular main chain, meanwhile, bio-based polyol with high hydrophobicity is adopted as a chain extender, the isocyanate index R value is regulated and controlled to be 0.70-0.90, and the prepared sealing material can meet the repeated debugging process requirement after thread installation; and meanwhile, the sealing and anti-corrosion requirements of the connecting threads under the seawater environment and the alternating stress load are met.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and particularly relates to a sealing material, a preparation method thereof and an application thereof. Background Art

[0002] In the ship field, in order to meet the requirements of installation, commissioning, maintenance and disassembly, etc., threaded connections are widely used in the transmission parts of transmission devices. The threaded joints are long-term in the corrosive environment of seawater immersion or wet-dry alternation, and bear large alternating loads for a long time during navigation. There are relatively serious crevice corrosion problems in the connecting threads of the transmission device. Therefore, sealing the threads to isolate the penetration of the medium is an important technical means to prevent thread corrosion.

[0003] The main methods of thread sealing are polytetrafluoroethylene tape sealing and coating sealants. Patent CN117050684A discloses a semi-dry viscoelastic sealant, a preparation method thereof and an application thereof. The sealant prepared by this method encapsulates isocyanate microcapsules. During the process of thread disassembly and installation, the rupture of isocyanate is uncontrollable, and the curing of the organic coating is irregular, and the debugging process of the thread cannot be effectively realized. CN112961550A discloses an anti-corrosion sealing synthetic material for oil pipe threads. By introducing graphene, the performance is significantly improved, and the anti-corrosion and wear resistance of the film layer are improved. However, the dosage of graphene is large and the price is expensive, which is limited in practical applications. In addition, the commonly used thread locking glue is easy to be damaged during the installation, commissioning and use of the device, and does not meet the protection requirements of the connecting threads of the transmission device.

[0004] Therefore, it is urgent to develop a new type of sealing material to meet the requirements of the repeated debugging process after thread installation, and to meet the sealing and anti-corrosion requirements of the connecting threads under the seawater environment and alternating stress loads. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a sealing material, a preparation method thereof and an application thereof, aiming to solve the technical problems that the existing sealing materials are easy to be stuck and damaged during the thread installation and debugging process, resulting in seal failure and poor anti-corrosion performance.

[0006] In a first aspect, an embodiment of the present invention provides a sealing material, which includes an isocyanate prepolymer and a chain extender, and the mass ratio of the isocyanate prepolymer to the chain extender is 130-268:100; The preparation raw materials of the isocyanate prepolymer, calculated by mass parts, include the following components: 17-34 parts of isocyanate monomer, 41-66 parts of hydroxyl-terminated fluorosilicone oil, 16-28 parts of castor oil-modified polyol; The raw materials for preparing the chain extender include the following components by mass: 80-95 parts of bio-based polyether polyol, 0.5-2.0 parts of surface modifier, 2-10 parts of anti-corrosion filler, 0.5-2.0 parts of anti-sagging thixotropic agent, 0.5-2.5 parts of water remover, 0.5-1.5 parts of dispersant, and 0.5-2 parts of corrosion inhibitor.

[0007] Preferably, the isocyanate index R value (isocyanate mole number: hydroxyl mole number) of the sealing material is 0.70-0.90.

[0008] Preferably, the mass percentage content of isocyanate groups in the isocyanate prepolymer is 4.0%-8.0%.

[0009] Preferably, the isocyanate monomer includes at least one of MDI-50, MDI-100, and toluene diisocyanate (TDI).

[0010] Preferably, the hydroxyl value of the castor oil-modified polyol is 85-115 mg KOH / g; the molecular weight of the castor oil-modified polyol is 1000-2000. The hydroxyl value of the castor oil-modified polyol within this range meets the synthesis requirements, and at the same time, the viscosity is appropriate and the flexibility is good.

[0011] Preferably, the bio-based polyether polyol includes cashew shell oil polyether polyol.

[0012] Preferably, the anti-corrosion filler includes a mixture of zinc tripolyphosphate and aluminum tripolyphosphate, and the mass ratio of zinc tripolyphosphate to aluminum tripolyphosphate is 1:1.

[0013] Preferably, the surface modifier includes γ-glycidoxypropyltrimethoxysilane KH-560.

[0014] Preferably, the anti-sagging thixotropic agent includes at least one of organic bentonite and polyamide wax.

[0015] Preferably, the water remover includes at least one of calcium oxide and molecular sieve.

[0016] In a second aspect, the present invention provides a method for preparing a sealing material, including the following steps: Vacuum dehydrate the castor oil-modified polyol and the hydroxyl-terminated fluorosilicone oil; mix the isocyanate monomer with the dehydrated hydroxyl-terminated fluorosilicone oil, react at 75-85 °C for 1-2 h, then add the dehydrated castor oil-modified polyol, and continue to react at 75-85 °C for 1-2 h to obtain an isocyanate prepolymer; High-speed stir the cashew shell oil polyether polyol, surface modifier, anti-corrosion filler, water remover, anti-sagging thixotropic agent, and dispersant, and then add the corrosion inhibitor and mix well to obtain a chain extender; Mix the isocyanate prepolymer and the chain extender evenly to obtain a sealing material.

[0017] Preferably, the conditions for water removal by vacuum pumping are as follows: the temperature is 100-110 °C and the pressure is 0.6-0.8 MPa.

[0018] Preferably, the high-speed stirring speed is 2000-3000 r / min.

[0019] In a third aspect, the present invention provides the use of the above-mentioned sealing material in thread seal anti-corrosion.

[0020] The principle of the technical solution of the present invention is as follows: Hydroxyfluorosilicone oil has a low surface tension, good hydrophobic moisture-proof and high-efficiency lubricating properties. After introducing fluorine elements into the polyurethane molecule, fluorine atoms migrate and accumulate on the surface of the polyurethane, improving the hydrophobicity of the molecular chain; bio-based polyether polyol has excellent hydrolysis stability, low humidity sensitivity and high elongation, and the characteristic of not deforming after long-term immersion in water. Cross-linking reaction with hydrophobic isocyanate prepolymer can further improve the hydrophobic and anti-corrosion properties of the polyurethane molecular chain. In terms of the design of the isocyanate index R value, the isocyanate index R value (mole number of isocyanate: mole number of hydroxyl group) is an important index to measure the reaction degree of isocyanate and the molecular weight of the synthesized product. When the R value is greater than 1, the molecule is chain-extended and cross-linked, and the end group is an isocyanate group, forming a cross-linked rigid polyurethane coating; when the R value is between 0.9 and 1, the molecular weight is too large and the viscosity is too high; when the R value is between 0.7 and 0.9, the molecular weight of the polyurethane material is moderate, the gel content is high, and the mechanical strength is excellent; but when the R value is less than 0.7, the reaction is extremely insufficient, the cross-linking degree is low, the molecular weight is too small, and it is easy to cause the mechanical properties of the material to decline.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The sealing material provided by the present invention is a long-term difficult-to-hardened and viscous polyurethane sealing material prepared with an isocyanate index R (mole ratio of isocyanate to hydroxyl group) of 0.70-0.90, which can realize the repeated disassembly and assembly of threaded joints to adapt to the long-cycle installation and commissioning process. At the same time, it can meet the high tensile (compressive) loading requirements of the thread during service to prevent the sealant from being damaged during stress loading, resulting in seal failure.

[0022] (2) The sealing material provided by the present invention introduces hydroxyfluorosilicone oil with a low surface energy. After introducing fluorine into the polyurethane, it migrates and accumulates on the surface of the polyurethane, improving the hydrophobicity of the polyurethane surface; at the same time, using bio-based polyether polyol with hydrolysis stability, low humidity sensitivity and high elongation as the chain extender to optimize the hydrophobicity of the hard segment of the polyurethane, thereby enhancing the hydrophobic and anti-corrosion properties of the sealing material in terms of molecular structure.

[0023] (3)In the preparation method of the sealing material provided by the present invention, hydroxyfluorosilicone oil and isocyanate monomer are first put in for cross-linking reaction, and then castor oil polyol is put in, so that the low-reactivity hydroxyfluorosilicone oil can be successfully introduced into the isocyanate prepolymer.

[0024] (4)The sealing material provided by the present invention is a two-component solvent-free system. An anti-sagging thixotropic agent is added to facilitate the brushing construction during screw installation in the initial mixing stage; a corrosion inhibitor and an anti-corrosion filler are added to increase the anti-corrosion reliability of the sealing material; a surface modifier is added to further enhance its bonding strength with the substrate and the anti-seawater penetration performance at the interface, and improve the comprehensive anti-corrosion property of the sealing material. Description of the Drawings

[0025] Figure 1 It is the infrared spectrum diagram of component A in Example 1 of the present invention; Figure 2 It is the test result diagram of the water contact angle of the specimen made by coating the sealing material prepared in Examples 1-5 of the present invention onto the thread; Figure 3 It is the test result diagram of the water contact angle of the specimen made by coating the sealing material prepared in Comparative Examples 1-6 of the present invention onto the thread; Figure 4 It is the corrosion situation of the specimen made by coating the sealing material prepared in Examples 1-5 of the present invention onto the thread; Figure 5 It is the corrosion situation of the specimen made by coating the sealing material prepared in Comparative Examples 1-6 of the present invention onto the thread. Detailed Embodiments

[0026] Hereinafter, embodiments of the technical solution of the present invention will be described in detail with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0027] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention and cannot be construed as a limitation of the present invention. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0028] In the following examples and comparative examples of the present invention, the castor oil-modified polyol was purchased from Anshan Chuangye Bio-New Material Technology Co., Ltd. The hydroxyl value of the castor oil-modified polyol was 100 mg KOH / g, the functionality was 3, and the average molecular weight was 1683 g / mol.

[0029] In the following examples and comparative examples of the present invention, the hydroxyl-terminated fluorosilicone oil was purchased from Shanghai Guishan High Polymer Materials Co., Ltd., the average molecular weight of the hydroxyl-terminated fluorosilicone oil was 2000 g / mol, and the functionality was 2.

[0030] In the following examples and comparative examples of the present invention, the cashew shell oil polyether polyol was purchased from Cardolite Corporation, the hydroxyl value was 175 mg KOH / g, and the functionality was 3.3.

[0031] In the following examples and comparative examples of the present invention, the anti-corrosion filler was a mixture of zinc tripolyphosphate and aluminum tripolyphosphate, and the mass ratio of zinc tripolyphosphate to aluminum tripolyphosphate was 1:1.

[0032] In the following examples and comparative examples of the present invention, the surface modifier was γ-glycidoxypropyltrimethoxysilane KH-560.

[0033] In the following examples and comparative examples of the present invention, the calculation method of the isocyanate index R value is as follows: (1) The content of isocyanate groups in component A was measured as W according to the method of standard HGT 2409-1992 (Determination of Isocyanate Group Content in Polyurethane Prepolymers). (NCO) 。

[0034] (2) The hydroxyl value OVH (mg KOH / g) in component B was measured by titration according to the standard GB / T 12008.3-2009 (Plastics - Polyether Polyols - Part 3: Determination of Hydroxyl Value).

[0035] (3) According to the relationship between the NCO content, hydroxyl value and R value, it can be converted into the following formula: R value = n （NCO） / n （OH） = (M （A） ×W (NCO) ×56.1) / (OVH×M （B） ×42×10 -3 )。

[0036] I. Preparation Method Example 1 A sealing material was prepared as follows: S1. Preparation of component A (isocyanate prepolymer): Castor oil-modified polyol and hydroxyl-terminated fluorosilicone oil (molecular weight 2000) were vacuum dehydrated at 110 °C and 0.6 MPa for 1 h and then stored sealed; by mass, 23 parts of diphenylmethane diisocyanate (MDI-50) were put into a reaction kettle, stirring was started, and then 61 parts of the dehydrated hydroxyl-terminated fluorosilicone oil were added. After reacting at 80 °C for 1.5 h, 16 parts of the dehydrated castor oil-modified polyol were added, and the reaction was continued at 80 °C for 1.5 h to obtain the isocyanate prepolymer A component; the A component W was measured. (NCO) was 4.02%; S2. Preparation of component B (chain extender): By mass, 90 parts of cashew shell oil polyether polyol, 1.0 part of KH-560, 6.0 parts of anti-corrosion filler, 0.5 part of calcium oxide (water remover), 1.5 parts of organic bentonite (anti-sagging thixotropic agent), and 0.5 part of dispersant (Elementis 904s) were dispersed in a disperser at 2000 r / min for 1.0 h, and then 0.5 part of corrosion inhibitor (phosphonate) was added and mixed for 10 min to obtain the chain extender B component. The OVH of the B component was measured to be 157.5 mg KOH / g; S3. According to the isocyanate index R value of 0.9, 268 parts of component A and 100 parts of component B were mixed evenly by mass to obtain a sealing material.

[0037] The infrared spectrum of component A in Example 1 is as Figure 1 shown. It can be seen that 1720 cm -1 is the stretching vibration peak of the ester group and urethane on the castor oil, and the N-H stretching vibration peak in the urethane is between 3300 - 3500 cm -1 . 1211 cm -1 is the stretching vibration of the C-F bond, 2258 cm -1 is the characteristic absorption peak of the NCO group in component A, 1521 cm -1 is the characteristic peak of the benzene ring skeleton, and 1016 cm -1 is the asymmetric stretching vibration of Si-O-Si. The above shows that the hydroxyl groups of the hydroxyl-terminated fluorosilicone oil and the castor oil-modified polyol react with the isocyanate, and the A component containing a terminal NCO group can be successfully synthesized.

[0038] Example 2 A sealing material, the preparation method is as follows: S1. Preparation of component A (isocyanate prepolymer): The castor oil-modified polyol and the hydroxyl-terminated fluorosilicone oil were vacuum dehydrated at 110 °C and 0.7 MPa for 1 h and then stored in a sealed manner. By mass, 25 parts of diphenylmethane diisocyanate (MDI-100) were put into a reaction kettle, stirring was started, and then 47 parts of the dehydrated hydroxyl-terminated fluorosilicone oil were added. After reacting at 75 °C for 1.5 h, 28 parts of the dehydrated castor oil-modified polyol were added, and the reaction was continued at 75 °C for 1.5 h to obtain the isocyanate prepolymer component A. The component A was measured to have a W (NCO) of 4.03%; S2. Preparation of component B (chain extender): By mass, 90 parts of cashew shell oil polyether polyol, 1.0 part of KH-560, 6 parts of anti-corrosion filler, 0.5 part of molecular sieve (water remover), 1.5 parts of organic bentonite (anti-sagging thixotropic agent), and 0.5 part of dispersant (Hydropalat 904s) were dispersed in a disperser at 2000 r / min for 1.0 h, and then 0.5 part of corrosion inhibitor (phosphonate) was added and mixed for 10 min to obtain the chain extender component B. The component B was measured to have an OVH of 157.5 mg KOH / g; S3. According to the isocyanate index R value of 0.7, 207 parts of component A and 100 parts of component B were mixed evenly by mass to obtain the sealing material.

[0039] Example 3 A sealing material is prepared as follows: S1. Preparation of component A (isocyanate prepolymer): The castor oil-modified polyol and the hydroxyl-terminated fluorosilicone oil were vacuum dehydrated at 100 °C and 0.8 MPa for 1 h and then stored in a sealed manner. By mass, 30 parts of diphenylmethane diisocyanate (MDI-50) were put into a reaction kettle, stirring was started, 50 parts of the dehydrated hydroxyl-terminated fluorosilicone oil were added. After reacting at 80 °C for 1.5 h, 20 parts of the dehydrated castor oil-modified polyol were added, and the reaction was continued at 80 °C for 1.5 h to obtain component A. The component A was measured to have a W (NCO) of 6.48%; S2. Preparation of component B (chain extender): By mass, 80 parts of cashew shell oil polyether polyol, 2.0 parts of KH-560, 10.0 parts of anti-corrosion filler, 2.5 parts of calcium oxide (water remover), 2.0 parts of organic bentonite (anti-sagging thixotropic agent), and 1.5 parts of dispersant (Hydropalat 904s) were dispersed in a disperser at 3000 r / min for 1.0 h, and then 2.0 parts of corrosion inhibitor (phosphonate) were added and mixed for 10 min to obtain the chain extender component B. The component B was measured to have an OVH of 140 mg KOH / g; S3. Mix 130 parts of Component A and 100 parts of Component B evenly by mass according to an isocyanate index R value of 0.8 to obtain a sealing material.

[0040] Example 4 A sealing material is prepared as follows: S1. Prepare Component A (isocyanate prepolymer): Mix castor oil-modified polyol and hydroxyl-terminated fluorosilicone oil, evacuate and remove water at 105°C and 0.8 MPa for 1 h, and then store it sealed; by mass, put 17 parts of toluene diisocyanate (TDI) into the reaction kettle, start stirring, and then put 66 parts of dehydrated hydroxyl-terminated fluorosilicone oil, react at 85°C for 1.5 h, then put 17 parts of dehydrated castor oil-modified polyol, and continue to react at 85°C for 1.5 h to obtain Component A; measure that the water content W of Component A (NCO) is 4.03%; S2. Prepare Component B (chain extender): By mass, put 92 parts of cashew shell oil polyether polyol, 1.5 parts of KH-560, 2.0 parts of anti-corrosion filler, 0.5 part of molecular sieve (water remover), 2.0 parts of organic bentonite (anti-sagging thixotropic agent), and 1.0 part of dispersant (Elementis 904s) into the disperser and disperse at 2500 r / min for 1.0 h, then add 1.0 part of corrosion inhibitor (phosphonate) and mix for 10 min to obtain the chain extender Component B; measure that the hydroxyl value OVH of Component B is 161 mg KOH / g; S3. Mix 212 parts of Component A and 100 parts of Component B evenly by mass according to an isocyanate index R value of 0.7 to obtain a sealing material.

[0041] Example 5 A sealing material is prepared as follows: S1. Prepare Component A (isocyanate prepolymer): Mix castor oil-modified polyol and hydroxyl-terminated fluorosilicone oil, evacuate and remove water at 105°C and 0.8 MPa for 1 h, and then store it sealed; by mass, put 34 parts of diphenylmethane diisocyanate (MDI-50) into the reaction kettle, start stirring, and then put 41 parts of dehydrated hydroxyl-terminated fluorosilicone oil, react at 80°C for 1.5 h, then put 25 parts of dehydrated castor oil-modified polyol, and continue to react at 80°C for 1.5 h to obtain Component A; measure that the water content W of Component A (NCO) is 7.98%; S2. Prepare Component B (chain extender): By mass, 95 parts of cashew shell oil polyether polyol, 0.5 part of KH-560, 2.0 parts of anti-corrosion filler, 1.0 part of calcium oxide, 0.5 part of polyamide wax, and 0.5 part of dispersant (Elementis 904s) were dispersed in a dispersing machine at 2000 r / min for 1.0 h. Then, 0.5 part of corrosion inhibitor (phosphonate) was added and mixed for 10 min to obtain chain extender component B. The OVH of component B was measured to be 166.3 mg KOH / g; S3. With an isocyanate index R value of 0.9, 141 parts of component A and 100 parts of component B were mixed evenly by mass ratio to obtain a sealing material.

[0042] Comparative Example 1 The difference between this comparative example and Example 1 is that in step S3, the isocyanate index R value of component A and component B was set to 1.2, that is, 357 parts of component A and 100 parts of component B were mixed evenly by mass ratio to obtain a sealing material.

[0043] Comparative Example 2: The difference between this comparative example and Example 1 is that in step S3, the isocyanate index R of component A and component B was set to 0.95, that is, 283 parts of component A and 100 parts of component B were mixed evenly by mass ratio to obtain a sealing material.

[0044] Comparative Example 3: The difference between this comparative example and Example 1 is that in step S3, the isocyanate index R of component A and component B was set to 0.6, that is, 179 parts of component A and 100 parts of component B were mixed evenly by mass ratio to obtain a sealing material.

[0045] Comparative Example 4: The difference between this comparative example and Example 1 is that in step S1, hydroxyfluorosilicone oil and castor oil polyol were put into isocyanate monomer together, and the remaining steps were the same as those in Example 1. Step S1 is specifically: S1. Preparation of component A (isocyanate prepolymer): Castor oil-modified polyol and hydroxy-terminated fluorosilicone oil (molecular weight 2000) were vacuum dehydrated at 110 °C and 0.6 MPa for 1 h and then stored sealed. By mass, 23 parts of diphenylmethane diisocyanate (MDI-50) were put into a reaction kettle, stirring was started, and then 61 parts of hydroxy-terminated fluorosilicone oil and 16 parts of castor oil-modified polyol were added and reacted at 80 °C for 3 h to obtain component A; The W of component A was measured (NCO) to be 8.58%, and the W of component A in Example 1 (NCO)The deviation is relatively large, indicating that when hydroxyfluorosilicone oil and castor oil polyol are put into the reaction of isocyanate monomer together, a large amount of MDI does not participate in the reaction, which shows that the hydroxyfluorosilicone oil with fluorinated long carbon chain has low activity, and it is difficult for the hydroxyfluorosilicone oil to react completely, and the hydroxyfluorosilicone oil is not successfully introduced into the isocyanate prepolymer.

[0046] Comparative Example 5: The difference between this comparative example and Example 1 is that the hydroxyfluorosilicone oil is not contained in Component A.

[0047] A sealing material, the preparation method is as follows: S1. Prepare Component A (isocyanate prepolymer): The castor oil-modified polyol is vacuum dehydrated at 110 °C and 0.6 MPa for 1 h and then stored in a sealed manner; by mass, 28 parts of diphenylmethane diisocyanate (MDI-50) are put into the reaction kettle, stirring is started, and then 72 parts of castor oil-modified polyol are put in, and the reaction is carried out at 80 °C for 3 h to obtain Component A, and the measured Component A W (NCO) is 3.98%; S2. Prepare Component B (chain extender): By mass, 90 parts of cashew shell oil polyether polyol, 1.0 part of KH-560, 6.0 parts of anti-corrosion filler, 0.5 part of calcium oxide, 1.5 parts of organic bentonite, and 0.5 part of dispersant (Elementis 904s) are dispersed in a disperser at 2000 r / min for 1.0 h, and then 0.5 part of corrosion inhibitor (phosphonate) is added and mixed for 10 min to obtain the chain extender Component B, and the measured Component B OVH is 157.5 mg KOH / g; S3. According to the isocyanate index R value of 0.9, 264 parts of Component A and 100 parts of Component B are mixed evenly by mass ratio to obtain the sealing material.

[0048] Comparative Example 6: The difference between this comparative example and Example 1 is that the cashew shell oil polyether polyol in Component B is replaced by 1,4-butanediol.

[0049] A sealing material, the preparation method is as follows: S1. Prepare Component A (isocyanate prepolymer): The castor oil-modified polyol and hydroxyfluorosilicone oil (molecular weight 2000) are vacuum dehydrated at 110 °C and 0.6 MPa for 1 h and then stored in a sealed manner; by mass, 23 parts of diphenylmethane diisocyanate (MDI-50) are put into the reaction kettle, stirring is started, and then 61 parts of hydroxyfluorosilicone oil are put in, and after reacting at 80 °C for 1.5 h, 16 parts of castor oil-modified polyol are put in, and the reaction is continued at 80 °C for 1.5 h to obtain Component A, and the measured Component A W (NCO) is 4.02%; S2. Preparation of Component B (chain extender): By mass, 90 parts of 1,4-butanediol, 1.0 part of KH-560, 6.0 parts of anti-corrosion filler, 0.5 part of calcium oxide, 1.5 parts of organic bentonite, and 0.5 part of dispersant (Elementis 904s) were dispersed in a disperser at 2000 r / min for 1.0 h. Then, 0.5 part of corrosion inhibitor (phosphonate) was added and mixed for 10 min to obtain the chain extender Component B. The OVH of Component B was measured to be 1120 mgKOH / g; S3. According to the isocyanate index R value of 0.9, 1903 parts of Component A and 100 parts of Component B were mixed evenly by mass ratio to obtain the sealing material.

[0050] II. Test methods The materials prepared in Examples 1-5 and Comparative Examples 1-6 above were respectively coated on a 27-mm diameter thread to make test specimens. After the coating was cured, the following performance tests were carried out, including: (1) Determination of coating torque: After the sealing material coated on each thread was completely cured, a torque wrench was used to measure the torque of the thread at 15 days, 1 month, 3 months, and 6 months respectively. Three thread samples were measured for each time period, and the results were averaged.

[0051] (2) Measurement of water contact angle: The water contact angle of the coating in the sample was measured on a water contact angle tester.

[0052] (3) Determination of anti-corrosion performance: The sealing material was brushed on the thread surface. After curing at room temperature for 7 days, it was subjected to 5000 cycles of stress alternating (0~60 KN, frequency 2 Hz, sinusoidal alternating), and at the same time, a 100-cycle test of seawater hydrostatic pressure alternating pressure (0 MPa~4.5 MPa~0 MPa) was carried out to observe the corrosion situation of the thread surface.

[0053] III. Analysis of test results of each example and comparative example The torque test, water contact angle, and anti-corrosion performance test results of the specimens prepared in Examples 1~5 and Comparative Examples 1~6 are shown in Tables 1~2. Figure 2 Among them, (a)~(e) are the water contact angle test result diagrams of the specimens made by coating the sealing materials prepared in Examples 1~5 of the present invention on the thread; Figure 3 Among them, (a)~(f) are the water contact angle test result diagrams of the specimens made by coating the sealing materials prepared in Comparative Examples 1~6 of the present invention on the thread; Figure 4 Among them, (a)~(e) are the corrosion situations of the specimens made by coating the sealing materials prepared in Examples 1~5 of the present invention on the thread; Figure 5 Among them, (a)~(f) are the corrosion situations of the specimens made by coating the sealing materials prepared in Comparative Examples 1~6 of the present invention on the thread.

[0054] Table 1: Torque test results of the sealing materials in Examples 1-5 and Comparative Examples 1-6

[0055] Table 2: Water contact angle and anti-corrosion test results of Examples 1-5 and Comparative Examples 1-6

[0056] In the coating torque test, a thread sealant with a torque less than 2 N·m is convenient for thread disassembly and installation after construction. In Examples 1-5 of the present invention, the torque is less than 2 N·m at 15 days, 1 month, 3 months, and 6 months. The two-component sealant is difficult to harden for a long time and can meet the disassembly and assembly of threads under long-term conditions. In Comparative Examples 1 and 2, the R value is greater than 0.9, and the torque of the sealant is greater than 2 N·m after 15 days, and the sealant is locked with the thread and cannot be disassembled. In Comparative Example 3, when the R value is 0.6, due to the too low crosslinking density of the sealing material, its corrosion resistance is poor during thread sealing. In the water contact angle test, the water contact angles of Examples 1-5 are 105°-120°, and the water contact angles of Comparative Examples 4-6 are less than 100°, indicating that the introduction of low-surface-energy fluorosilicone oil and hydrophobic bio-based polyols improves the hydrophobicity of the sealant. In the anti-corrosion performance test, the thread surfaces of Examples 1-5 have no corrosion, while the thread surfaces in Comparative Examples 3-6 all show corrosion.

[0057] In summary, the present invention uses the regulation of the isocyanate index R value (isocyanate mole number: hydroxyl mole number) to be 0.70-0.90, and introduces low-surface-energy, highly hydrophobic hydroxyl fluorosilicone oil and low-hydrolysis-resistance, highly hydrophobic bio-based polyols into the molecular chain to prepare a thread sealing material that can meet the debugging process, high hydrophobicity, and high anti-corrosion requirements, completely making up for the problems such as jamming and breakage of the sealant during the thread installation and debugging process, and at the same time solving the breakage and seal failure of the sealant during the stress loading process, so that the thread anti-corrosion material can not only meet the debugging process after installation but also meet the requirements of high-efficiency anti-corrosion sealing.

[0058] It should be noted that the present invention is not limited to the above embodiments. The above embodiments are only examples, and embodiments with the same composition and the same effect as the technical idea within the technical solution scope of the present invention are included in the technical scope of the present invention. In addition, within the scope not departing from the gist of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. A sealing material, characterized in that, It includes an isocyanate prepolymer and a chain extender; the mass ratio of the isocyanate prepolymer to the chain extender is 130 - 268:100; The raw materials for preparing the isocyanate prepolymer, by mass parts, include the following components: 17 - 34 parts of isocyanate monomer, 41 - 66 parts of hydroxyl-terminated fluorosilicone oil, 16 - 28 parts of castor oil-modified polyol; The raw materials for preparing the chain extender, by mass parts, include the following components: 80 - 95 parts of bio-based polyether polyol, 0.5 - 2.0 parts of surface modifier, 2 - 10 parts of anti-corrosion filler, 0.5 - 2.0 parts of anti-sagging thixotropic agent, 0.5 - 2.5 parts of water remover, 0.5 - 1.5 parts of dispersant, 0.5 - 2 parts of corrosion inhibitor.

2. The sealing material according to claim 1, wherein The isocyanate index R value (isocyanate mole number: hydroxyl mole number) of the sealing material is 0.70 - 0.

90.

3. A sealing material according to claim 1, characterized in that, The mass percentage content of isocyanate groups in the isocyanate prepolymer is 4.0% - 8.0%.

4. A sealing material according to claim 1, characterized in that, The isocyanate monomer includes at least one of MDI-50, MDI-100, and toluene diisocyanate.

5. A sealing material according to claim 1, characterized in that, The bio-based polyether polyol includes cashew shell oil polyether polyol.

6. A sealing material according to claim 1, characterized in that, The anti-corrosion filler includes a mixture of zinc tripolyphosphate and aluminum tripolyphosphate; the surface modifier includes γ-glycidoxypropyltrimethoxysilane; the anti-sagging thixotropic agent includes at least one of organic bentonite and polyamide wax; the water remover includes at least one of calcium oxide and molecular sieve.

7. The preparation method of the sealing material according to any one of claims 1 to 6, characterized in that, It includes the following steps: Vacuum dehydrate the castor oil-modified polyol and hydroxyl-terminated fluorosilicone oil, mix the isocyanate monomer with the dehydrated hydroxyl-terminated fluorosilicone oil, react at 75 - 85 °C for 1 - 2 h, then add the dehydrated castor oil-modified polyol, and continue to react at 75 - 85 °C for 1 - 2 h to obtain the isocyanate prepolymer; High-speed stir the cashew shell oil polyether polyol, surface modifier, anti-corrosion filler, water remover, anti-sagging thixotropic agent, and dispersant, then add the corrosion inhibitor and mix well to obtain the chain extender; Mix the isocyanate prepolymer and the chain extender evenly to obtain the sealing material.

8. The preparation method of the sealing material according to claim 7, characterized in that, The vacuum dehydration conditions are as follows: temperature is 100 - 110 °C, pressure is 0.6 - 0.8 MPa.

9. The preparation method of the sealing material according to claim 7, characterized in that, The rotation speed of the high-speed stirring is 2000 - 3000 r / min.

10. Application of the sealing material according to any one of claims 1 - 6 in thread seal anti-corrosion.

Images