Bi-component modified polysulfide sealant for binding surface as well as preparation method and application of bi-component modified polysulfide sealant

Abstract

The invention belongs to the technical field of polysulfide sealants, and relates to a bi-component modified polysulfide sealant for a binding surface as well as a preparation method and application of the bi-component modified polysulfide sealant. The bi-component modified polysulfide sealant for the binding surface is prepared from a component A and a component B according to the mass ratio of 100: (8-12), the component A comprises modified polysulfide rubber, a functional filler, a coupling agent, an adhesive and a regulator; the modified polysulfide rubber is prepared from polysulfide rubber and a modifier; the modifying agent is one of bis (2-chloroethyl) ether, 1, 2-dichloroethane and bis (chloromethyl) dimethylsilane; and the component B comprises a metal oxide, a plasticizer, an accelerant and a regulator. According to the modified polysulfide sealant formed by two components, the elongation at break of the polysulfide sealant is improved in an extreme environment, the sealant has excellent deformation resistance, cracking, shrinkage and bonding failure of a sealant layer are avoided, and the sealing performance of a binding surface is improved.

Description

Technical Field

[0001] This invention belongs to the field of polysulfide sealant technology, and relates to a two-component modified polysulfide sealant for bonding surfaces, its preparation method, and its application. Background Technology

[0002] Aircraft mating surface sealing has always been a critical aspect of ensuring the structural integrity, leak prevention, and protection of aircraft. The sealing performance of aircraft mating surfaces directly affects flight safety, reliability, and service life. Mating surface seals not only effectively isolate corrosive media such as moisture, salt, and dust, preventing electrochemical corrosion or oxidation of the mating surface metal components, but also must withstand the complex mechanical forces and environmental stresses during flight. Therefore, stringent requirements are placed on the comprehensive performance of sealing materials.

[0003] Currently, polysulfide sealant has become one of the mainstream materials for sealing aircraft mating surfaces due to its excellent fuel resistance, weather resistance, airtightness and good adhesion. It is widely used in key parts such as fuselage skin mating, engine compartment component mating and avionics equipment sealing. Its technological maturity and application popularity are in a core position in the aviation sealing field, and it is a key material support for ensuring the basic sealing function of aircraft.

[0004] However, the sealing environment of the bonding surface during the entire life cycle of an aircraft exhibits significant extremes and complexities: on the one hand, the temperature cycle impact during flight, from low ground temperatures to low high-altitude temperatures and the local high temperatures during engine operation, creates a range of temperatures from -55°C to 120°C or even wider, requiring the sealant to repeatedly undergo thermal expansion and contraction; on the other hand, continuous mechanical vibrations caused by engine vibration, airflow disturbances, and takeoff and landing impacts keep the sealant under dynamic stress for a long time; at the same time, the long-term corrosion from media such as aviation fuel, hydraulic oil, high-altitude ozone, and humidity changes further exacerbates the performance degradation of the sealant.

[0005] Under the long-term effects of extreme environments involving multiple factors such as temperature cycling, vibration, and erosion, the deformation resistance of existing single-component polysulfide sealants gradually decreases under these extreme conditions. They cannot continuously match the deformation requirements of the bonding surface, leading to phenomena such as cracking, shrinkage, and adhesion failure in the polysulfide sealant layer, resulting in sealing failure. This severely affects the sealing reliability of the aircraft bonding surface and may even lead to safety hazards.

[0006] Therefore, developing a two-component modified polysulfide sealant for bonding surfaces is of great significance for sealing aircraft bonding surfaces. Summary of the Invention

[0007] To address the technical problem that the deformation resistance of existing polysulfide sealants gradually decreases under long-term extreme environments, making it unable to continuously match the deformation requirements of the bonding surface, resulting in phenomena such as cracking, shrinkage, and peeling of the sealant layer from the bonding surface substrate, leading to sealing failure, this invention provides a two-component modified polysulfide sealant for bonding surfaces, its preparation method, and its application.

[0008] This invention uses a two-component modified polysulfide sealant to improve the elongation at break of the polysulfide sealant under extreme environments, resulting in excellent resistance to deformation and preventing cracking, shrinkage, and adhesion failure of the sealant layer, thereby improving the sealing performance of the bonding surface.

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0010] A two-component modified polysulfide sealant for bonding surfaces is made of component A and component B in a mass ratio of 100:(8-12);

[0011] The first component comprises the following raw materials in parts by weight: 95-105 parts modified polysulfide rubber, 10-20 parts functional filler, 0.5-1 part coupling agent, 0.5-1 part binder, and 0.5-1 part modifier;

[0012] The modified polysulfide rubber is made of polysulfide rubber and a modifier; the modifier is one of bis(2-chloroethyl) ether, 1,2-dichloroethane and bis(chloromethyl)dimethylsilane;

[0013] The B component comprises the following raw materials in parts by weight: 55-65 parts of metal oxide, 25-35 parts of plasticizer, 0.5-1 part of accelerator, and 0.5-1 part of regulator.

[0014] Further specifying, the functional filler is prepared by mixing precipitated SiO2 and nano SiO2 in a mass ratio of (35-45):(10-20); the particle size of the nano SiO2 is 50nm to 150nm.

[0015] Further specified, the coupling agent is one or both of silane coupling agents and phthalate coupling agents;

[0016] When the coupling agent is a silane coupling agent and a phthalate coupling agent, the mass ratio of the silane coupling agent to the phthalate coupling agent is (30-40):(5-10).

[0017] Further specified, the silane coupling agent is any one of vinyltriethylsilane, γ-glycidoxypropyltrimethylsilane, γ-mercaptopropyltriethoxysilane, and γ-aminopropyltriethoxysilane;

[0018] The phthalate coupling agent is any one of isopropyltris(isostearoyl) phthalate, isopropyltris(dodecylbenzenesulfonyl) phthalate, and isopropyltris(methacryloyloxy) phthalate.

[0019] Further specifying, the adhesive is epoxy resin; and the modifier in both component A and component B is stearic acid.

[0020] Further specifying, the metal oxide is any one of lead dioxide, manganese dioxide, and zinc oxide.

[0021] Further specifying, the plasticizer is any one of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and tributyl acetylacetonate.

[0022] Further specified, the accelerator is one or two of tetramethylthiuram disulfide, diphenylguanidine, 2-mercaptobenzothiazole, and dibenzothiazole disulfide;

[0023] When the accelerator is tetramethylthiuram disulfide and 2-mercaptobenzothiazole, the mass ratio of tetramethylthiuram disulfide to 2-mercaptobenzothiazole is (10-15):(3-5);

[0024] When the accelerator is tetramethylthiuram disulfide and dibenzothiazole disulfide, the mass ratio of tetramethylthiuram disulfide to dibenzothiazole disulfide is (10-15):(3-5).

[0025] A method for preparing a two-component modified polysulfide sealant for bonding surfaces, the method comprising the following steps:

[0026] S1. Preparation of modified polysulfide rubber

[0027] After adding a modifier to polysulfide rubber, the mixture is heated to 70-90℃ and stirred for 72-96 hours to obtain modified polysulfide rubber.

[0028] S2, Preparation of component A

[0029] Take the modified polysulfide rubber from step S1 according to the mass fraction, and then add the functional filler, coupling agent, adhesive and regulator in sequence; stir for 10 minutes after each addition of raw material to obtain component A;

[0030] S3. Preparation of component B

[0031] The metal oxide, plasticizer, accelerator and regulator are coarsely mixed according to the mass ratio, and then kneaded 3 to 6 times using a three-roll mill to obtain component B;

[0032] S4. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0033] After coarsely mixing components A and B according to their mass ratio, the mixture is then kneaded 3 to 6 times using a three-roll mill to obtain the final product.

[0034] Application of a two-component modified polysulfide sealant for bonding surfaces in improving elongation at break and resistance to deformation.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] 1. The present invention provides a two-component modified polysulfide sealant for bonding surfaces, wherein component A and component B are mixed in a mass ratio of 100:(8-12). This sealant improves the elongation at break of the polysulfide sealant under extreme conditions, exhibits excellent resistance to deformation, avoids cracking, shrinkage and adhesion failure of the sealant layer, and improves the sealing performance of the bonding surface.

[0037] 2. Through performance testing, the two-component modified polysulfide sealant used in this invention remains smooth on the metal surface after complete vulcanization on the metal surface and is placed in an environment of -55℃, without cracks or loss of adhesion, thus avoiding cracking, shrinkage and adhesion failure of the sealant layer.

[0038] 3. Performance testing of this invention shows that the two-component modified polysulfide sealant for bonding surfaces, after complete vulcanization, exhibits an elongation at break exceeding 500% in Type I tensile specimens prepared according to GB / T528-2009 at room temperature; after six standard thermal cycles (127℃×4h→160℃×40min→180℃×1h), the elongation at break still reaches 228%. This invention improves the elongation at break of the sealant for bonding surfaces under different environmental conditions while meeting the tensile strength requirements of the application scenario, thereby enhancing its resistance to deformation. Detailed Implementation

[0039] The present invention will now be described in detail with reference to specific embodiments. However, the embodiments of the present invention include, but are not limited to, the scope represented by the following embodiments. Any equivalent modifications made by those skilled in the art to the technical solutions of the present invention by reading the present invention shall be covered by the claims of the present invention.

[0040] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0041] This invention provides a two-component modified polysulfide sealant for bonding surfaces, which is made of component A and component B in a mass ratio of 100:(8-12).

[0042] For example, the mass ratio of component A to component B is 100:8, 100:9, 100:10, 100:11 or 100:12; preferably, the mass ratio of component A to component B is 100:10.

[0043] In this invention, component A comprises the following raw materials in parts by weight: 95-105 parts modified polysulfide rubber, 10-20 parts functional filler, 0.5-1 part coupling agent, 0.5-1 part binder, and 0.5-1 part regulator.

[0044] Preferably, the modified polysulfide rubber is made of polysulfide rubber and a modifier; the modifier is one of bis(2-chloroethyl) ether, 1,2-dichloroethane and bis(chloromethyl)dimethylsilane.

[0045] The polysulfide rubber is liquid polysulfide rubber, preferably one of the following models: JLY-155, JLY-215, and JLY-124. All polysulfide rubbers are purchased from Jinxi Chemical Research Institute.

[0046] In this invention, the functional filler is prepared by mixing precipitated SiO2 and nano SiO2 in a mass ratio of (35-45):(10-20); the particle size of the nano SiO2 is 50nm to 150nm.

[0047] For example, the mass ratio of precipitated SiO2 to nano-SiO2 is 35:10, 35:15, 35:20, 40:10, 40:15, 40:20, 45:10, 45:15, or 45:20. The particle size of nano-SiO2 is 50 nm, 100 nm, or 150 nm.

[0048] In this invention, the coupling agent is one or both of silane coupling agents and phthalate coupling agents.

[0049] In this invention, when the coupling agent is a silane coupling agent and a phthalate coupling agent, the mass ratio of the silane coupling agent to the phthalate coupling agent is (30-40):(5-10).

[0050] For example, the mass ratio of silane coupling agent to phthalate coupling agent is 30:5, 30:10, 35:5, 35:10, 40:5, or 40:10.

[0051] In this invention, the silane coupling agent is any one of vinyltriethylsilane, γ-glycidoxypropyltrimethylsilane, γ-mercaptopropyltriethoxysilane, and γ-aminopropyltriethoxysilane.

[0052] In this invention, the phthalate coupling agent is any one of isopropyltris(isostearoyl)phthalate, isopropyltris(dodecylbenzenesulfonyl)phthalate, and isopropyltris(methacryloyloxy)phthalate.

[0053] In this invention, the adhesive is epoxy resin; specifically, the epoxy resin is bisphenol A type epoxy resin, such as E44 epoxy resin, E51 epoxy resin, or E35 epoxy resin; all are conventional commercially available products purchased from the market. The modifier in component B is stearic acid.

[0054] In this invention, component B comprises the following raw materials in parts by weight: 55-65 parts of metal oxide, 25-35 parts of plasticizer, 0.5-1 part of accelerator, and 0.5-1 part of regulator.

[0055] The regulator in component B of this invention is also stearic acid.

[0056] In this invention, the metal oxide is any one of lead dioxide, manganese dioxide, and zinc oxide.

[0057] In this invention, the plasticizer is any one of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and tributyl acetylacetate.

[0058] In this invention, the accelerator is one or two of tetramethylthiuram disulfide, diphenylguanidine, 2-mercaptobenzothiazole, and dibenzothiazole disulfide.

[0059] Preferably, when the accelerator is tetramethylthiuram disulfide and 2-mercaptophenthiazole, the mass ratio of tetramethylthiuram disulfide to 2-mercaptophenthiazole is (10-15):(3-5).

[0060] Preferably, when the accelerator is tetramethylthiuram disulfide and dibenzothiazole disulfide, the mass ratio of tetramethylthiuram disulfide to dibenzothiazole disulfide is (10-15):(3-5).

[0061] This invention also provides a method for preparing a two-component modified polysulfide sealant for bonding surfaces, comprising the following steps:

[0062] S1. Preparation of modified polysulfide rubber

[0063] After adding a modifier to polysulfide rubber, the mixture is heated to 70-90℃ and stirred for 72-96 hours to obtain modified polysulfide rubber.

[0064] S2, Preparation of component A

[0065] Take the modified polysulfide rubber from step S1 according to the mass fraction, and then add the functional filler, coupling agent, adhesive and regulator in sequence; stir for 10 minutes after each addition of raw material to obtain component A;

[0066] For example, a planetary mixer is used to prepare component A. Specifically, for each raw material added, the stirring shaft speed is set to 80 r / min and the dispersion shaft speed is set to 1500 r / min. Alternatively, other mixing equipment can be used to ensure that all raw materials of component A are dispersed and mixed evenly.

[0067] S3. Preparation of component B

[0068] The metal oxide, plasticizer, accelerator and regulator are coarsely mixed according to the mass fraction, and then kneaded 3 to 6 times using a three-roll mill to obtain component B;

[0069] S4. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0070] After coarsely mixing components A and B according to their mass ratio, the mixture is then kneaded 3 to 6 times using a three-roll mill.

[0071] The present invention also provides an application of a two-component modified polysulfide sealant for bonding surfaces in improving elongation at break and resistance to deformation.

[0072] The above-mentioned technical solutions of the present invention are described below with several examples and performance tests.

[0073] It should be noted that, unless otherwise specified, the chemicals and reagents used in the following embodiments are all commercially available products commonly used in the field.

[0074] It should be noted that, unless otherwise specified, the operations used in the following embodiments are all conventional operations, and the test methods are all existing standard test methods in the art.

[0075] Example 1

[0076] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0077] S1. Preparation of component A

[0078] Modified polysulfide rubber was synthesized by adding 5 parts of bis(chloromethyl)dimethylsilane to 100 parts of polysulfide rubber JLY-155, heating to 80℃, and stirring for 72 hours with the dispersion shaft speed of a planetary mixer set to 80 r / min.

[0079] Add 80 parts of modified polysulfide rubber to a planetary mixer, then add 10 parts of precipitated SiO2, 5 parts of nano-SiO2 with a particle size of 50 nm, 0.7 parts of silane coupling agent (vinyltriethylsilane), 0.3 parts of phthalate coupling agent (isopropyltris(methacryloyloxy)phthalate), 3 parts of E44 epoxy resin, and 1 part of stearic acid in sequence. For each addition of raw material, set the stirring shaft speed to 80 r / min and the dispersion shaft speed to 1500 r / min, and stir for 10 min to obtain component A.

[0080] S2, Preparation of component B

[0081] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 35 parts of tributyl acetyl citrate, 1 part of tetramethylthiuram disulfide, 3 parts of 2-mercaptobenzothiazole, and 1 part of stearic acid, and then kneading them four times using a three-roll mill.

[0082] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0083] Component A and Component B are weighed and coarsely mixed at a mass ratio of 100:9, and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0084] Example 2

[0085] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0086] S1. Preparation of component A

[0087] 6 parts of 1,2-dichloroethane were added to 100 parts of polysulfide rubber JLY-155, the temperature was raised to 90℃, and the dispersion shaft speed of the planetary mixer was set to 80 r / min. After stirring for 96 h, the modified polysulfide rubber was synthesized.

[0088] Add 75 parts of modified polysulfide rubber to a planetary mixer, then add 15 parts of precipitated SiO2, 6 parts of nano-SiO2 with a particle size of 150 nm, 0.6 parts of silane coupling agent (γ-mercaptopropyltriethoxysilane), 0.4 parts of phthalate coupling agent (isopropyltris(dodecylbenzenesulfonyl)phthalate), 2 parts of E44 epoxy resin, and 1 part of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80 r / min and the dispersion shaft speed to 1500 r / min, and stir for 10 min to obtain component A.

[0089] S2, Preparation of component B

[0090] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 30 parts of dibutyl phthalate, 6 parts of diphenylguanidine, and 4 parts of stearic acid, and then kneading them three times using a three-roll mill.

[0091] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0092] After weighing and coarsely mixing components A and B at a mass ratio of 100:11, the mixture is then kneaded three times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0093] Example 3

[0094] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0095] S1. Preparation of component A

[0096] After adding 7 parts of bis(2-chloroethyl) ether to 100 parts of polysulfide rubber JLY-215, the temperature was raised to 90℃ and the dispersion shaft speed of the planetary mixer was set to 80 r / min. After stirring for 96 h, the modified polysulfide rubber was synthesized.

[0097] Add 75 parts of modified polysulfide rubber to a planetary mixer, then add 15 parts of precipitated SiO2, 7 parts of nano-SiO2 with a particle size of 50nm, 1 part of silane coupling agent (vinyltriethylsilane), 1 part of E51 epoxy resin, and 1 part of stearic acid in sequence. For each addition of a raw material, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min, and stir for 10min to obtain component A.

[0098] S2, Preparation of component B

[0099] Component B is obtained by coarsely mixing 65 parts of manganese dioxide, 25 parts of dibutyl phthalate, 2 parts of tetramethylthiuram disulfide, 5 parts of diphenylguanidine, and 3 parts of stearic acid, and then kneading them four times using a three-roll mill.

[0100] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0101] Component A and Component B are weighed and coarsely mixed at a mass ratio of 100:9, and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0102] Example 4

[0103] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0104] S1. Preparation of component A

[0105] 5 parts of 1,2-dichloroethane were added to 100 parts of polysulfide rubber JLY-124, the temperature was raised to 90℃, and the dispersion shaft speed of the planetary mixer was set to 80 r / min. After stirring for 72 h, the modified polysulfide rubber was synthesized.

[0106] After adding 80 parts of modified polysulfide rubber to a planetary mixer, 10 parts of precipitated SiO2, 5 parts of nano-SiO2 with a particle size of 150 nm, 0.9 parts of silane coupling agent (γ-mercaptopropyltriethoxysilane), 0.6 parts of phthalate coupling agent (isopropyltris(methacryloyloxy)phthalate), 2.5 parts of E35 epoxy resin, and 1 part of stearic acid were added sequentially. For each raw material added, the stirring shaft speed was set to 80 r / min, the dispersion shaft speed was set to 1500 r / min, and the mixture was stirred for 10 min to obtain component A.

[0107] S2, Preparation of component B

[0108] After coarsely mixing 60 parts of manganese dioxide, 30 parts of dioctyl adipate, 4 parts of diphenylguanidine, 3-10 parts of dibenzothiazole disulfide and 3 parts of stearic acid, the mixture is then kneaded 5 times using a three-roll mill to obtain component B.

[0109] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0110] Component A and Component B are weighed and coarsely mixed at a mass ratio of 100:9, and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0111] Example 5

[0112] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0113] S1. Preparation of component A

[0114] Modified polysulfide rubber was synthesized by adding 6 parts of bis(2-chloroethyl) ether to 100 parts of polysulfide rubber JLY-155, heating to 85℃, and stirring for 70h with the dispersion shaft speed of a planetary mixer set to 80r / min.

[0115] 75 parts of modified polysulfide rubber were added to a planetary mixer, followed by 15 parts of precipitated SiO2, 4 parts of nano-SiO2 with a particle size of 50 nm, 0.8 parts of silane coupling agent (γ-aminopropyltriethoxysilane), 0.4 parts of phthalate coupling agent (isopropyltris(dodecylbenzenesulfonyl)phthalate), 2.5 parts of E51 epoxy resin, and 2.3 parts of stearic acid. For each addition of a raw material, the stirring shaft speed was set to 80 r / min, the dispersion shaft speed was set to 1500 r / min, and the mixture was stirred for 10 min to obtain component A.

[0116] S2, Preparation of component B

[0117] Component B is obtained by coarsely mixing 55 parts of lead dioxide, 30 parts of dibutyl phthalate, 3 parts of tetramethylthiuram disulfide, 5 parts of dibenzothiazole disulfide, and 7 parts of stearic acid, and then kneading them 6 times using a three-roll mill.

[0118] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0119] Component A and Component B are weighed and coarsely mixed at a mass ratio of 100:12, and then kneaded five times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0120] Example 6

[0121] This embodiment provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0122] S1. Preparation of component A

[0123] 7 parts of bis(chloromethyl)dimethylsilane were added to 100 parts of polysulfide rubber JLY-155, the temperature was raised to 90℃, and the dispersion shaft speed of the planetary mixer was set to 80 r / min. After stirring for 96 h, the modified polysulfide rubber was synthesized.

[0124] Add 75 parts of modified polysulfide rubber to a planetary mixer, then add 15 parts of precipitated SiO2, 8 parts of nano-SiO2 with a particle size of 100nm, 0.5 parts of silane coupling agent (γ-aminopropyltriethoxysilane), 1 part of E44 epoxy resin, and 0.5 parts of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min, and stir for 10min to obtain component A.

[0125] S2, Preparation of component B

[0126] Component B is obtained by coarsely mixing 60 parts of zinc oxide, 30 parts of dioctyl phthalate, 1 part of tetramethylthiuram disulfide, 4 parts of diphenylguanidine, and 5 parts of stearic acid, and then kneading them 4 times using a three-roll mill.

[0127] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0128] Component A and Component B are weighed and coarsely mixed at a mass ratio of 100:10, and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0129] The performance of the two-component modified polysulfide sealant for bonding surfaces prepared in the above embodiments is tested below. In order to highlight the technical advantages of the present invention, the following comparative examples are designed.

[0130] Example 1 was not modified.

[0131] This comparative example provides a two-component polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0132] S1. Preparation of component A

[0133] Take 80 parts of polysulfide rubber JLY-155 and add it to a planetary mixer. Then, add 10 parts of precipitated SiO2, 5 parts of nano SiO2 with a particle size of 50nm, 0.7 parts of silane coupling agent (vinyltriethylsilane), 0.3 parts of phthalate coupling agent (isopropyltris(methacryloyloxy)phthalate), 3 parts of E44 epoxy resin and 1 part of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min, and stir for 10min to obtain component A.

[0134] S2, Preparation of component B

[0135] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 35 parts of tributyl acetyl citrate, 1 part of tetramethylthiuram disulfide, 3 parts of 2-mercaptobenzothiazole, and 1 part of stearic acid, and then kneading them four times using a three-roll mill.

[0136] S3. Preparation of two-component polysulfide sealant for bonding surfaces

[0137] Component A and Component B are coarsely mixed at a mass ratio of 100:9, and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0138] Example 2 was not modified.

[0139] This comparative example provides a two-component polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0140] S1. Preparation of component A

[0141] Take 80 parts of polysulfide rubber JLY-215 and add it to a planetary mixer. Then add 10 parts of precipitated SiO2, 5 parts of nano SiO2 with a particle size of 50nm, 0.7 parts of silane coupling agent (vinyltriethylsilane), 0.3 parts of phthalate coupling agent (isopropyltris(methacryloyloxy)phthalate), 3 parts of E44 epoxy resin and 1 part of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min, and stir for 10min to obtain component A.

[0142] S2, Preparation of component B

[0143] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 35 parts of tributyl acetyl citrate, 1 part of tetramethylthiuram disulfide, 3 parts of 2-mercaptobenzothiazole, and 1 part of stearic acid, and then kneading them four times using a three-roll mill.

[0144] S3. Preparation of two-component polysulfide sealant for bonding surfaces

[0145] Component A and Component B are coarsely mixed at a mass ratio of 100:9 and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0146] Example 3 was not modified.

[0147] This comparative example provides a two-component polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0148] S1. Preparation of component A

[0149] Take 80 parts of polysulfide rubber JLY-124 and add it to a planetary mixer. Then add 10 parts of precipitated SiO2, 5 parts of nano SiO2 with a particle size of 50nm, 0.7 parts of silane coupling agent (vinyltriethylsilane), 0.3 parts of phthalate coupling agent (isopropyltris(methacryloyloxy)phthalate), 3 parts of E44 epoxy resin and 1 part of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min, and stir for 10min to obtain component A.

[0150] S2, Preparation of component B

[0151] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 35 parts of tributyl acetyl citrate, 1 part of tetramethylthiuram disulfide, 3 parts of 2-mercaptobenzothiazole, and 1 part of stearic acid, and then kneading them four times using a three-roll mill.

[0152] S3. Preparation of two-component polysulfide sealant for bonding surfaces

[0153] Component A and Component B are coarsely mixed at a mass ratio of 100:9 and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0154] Control Example 4: No coupling agent added

[0155] This comparative example provides a two-component modified polysulfide sealant for bonding surfaces, the preparation method of which includes the following steps:

[0156] S1. Preparation of component A

[0157] 5 parts of bis(chloromethyl)dimethylsilane were added to 100 parts of polysulfide rubber JLY-155, the temperature was raised to 80℃, and the dispersion shaft of the planetary mixer was set to 80 r / min. The mixture was stirred for 72 h to synthesize the modified polysulfide rubber.

[0158] Take 80 parts of modified polysulfide rubber and add it to a planetary mixer. Then add 10 parts of precipitated SiO2, 5 parts of nano SiO2 with a particle size of 50nm, 3 parts of E44 epoxy resin and 1 part of stearic acid in sequence. For each raw material added, set the stirring shaft speed to 80r / min and the dispersion shaft speed to 1500r / min. Stir for 10min to obtain component A.

[0159] S2, Preparation of component B

[0160] Component B is obtained by coarsely mixing 60 parts of manganese dioxide, 35 parts of tributyl acetyl citrate, 1 part of tetramethylthiuram disulfide, 3 parts of 2-mercaptobenzothiazole, and 1 part of stearic acid, and then kneading them four times using a three-roll mill.

[0161] S3. Preparation of two-component modified polysulfide sealant for bonding surfaces

[0162] Component A and Component B are coarsely mixed at a mass ratio of 100:9 and then kneaded four times using a three-roll mill to obtain a two-component modified polysulfide sealant for bonding surfaces that can be applied.

[0163] The following performance tests were conducted.

[0164] 1. Tensile properties test at room temperature

[0165] The prepared sealant was used to prepare Type I tensile specimens according to GB / T 528-2009. After complete vulcanization, the room temperature elongation at break was tested. The test results are shown in Table 1 and Table 2.

[0166] Table 1. Determination of room temperature elongation at break in examples of raw rubber with and without modification.

[0167] sample Compare with Example 1 Compare with Example 2 Compare with Example 3 Compare with Example 4 Example 1 Elongation at break / % 246 289 277 367 517

[0168] As can be seen from Table 1, with the other components of the formulation unchanged, the sealants of Control Examples 1, 2, and 3, which used the original rubber without modification, had an elongation at break of less than 300% at room temperature after complete curing. In contrast, the sealant prepared in Example 1, which used the modified original rubber, had an elongation at break of 517%. The tensile properties of the modified polysulfide sealant are significantly better than those of the conventional unmodified polysulfide sealant.

[0169] Meanwhile, the remaining components of the formulation remained unchanged. The sealant of Control Example 4, which did not contain a coupling agent, had a room temperature elongation at break of 367% after complete curing, while the sealant prepared in Example 1, which contained a coupling agent, had an elongation at break of 517%. The addition of the coupling agent enhanced the interfacial bonding force between the filler and the modified raw rubber matrix, improved the dispersion performance, and further enhanced the tensile properties.

[0170] Table 2. Measurement of room temperature elongation at break in different examples using modified virgin rubber.

[0171] Example Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Elongation at break / % 517 533 543 513 522 556

[0172] As shown in Table 2, the room temperature elongation at break of all sealants using the modified virgin rubber after complete curing was greater than 500%, indicating that the modified polysulfide sealant of this invention, formed by two components, has excellent resistance to deformation, avoiding cracking, shrinkage, and adhesion failure of the sealant layer, and exhibiting excellent sealing performance. Meanwhile, the modified polysulfide sealant prepared in Example 6 achieved the optimal elongation at break. The following performance tests are all based on Example 6.

[0173] 2. Low-temperature flexibility test

[0174] In Example 6, the prepared sealant was used to prepare standard samples according to the method in HB5274-93. After complete vulcanization, the surface state and adhesion were observed at different temperatures. The test results are shown in Table 3.

[0175] Table 3. Low-temperature softness test results at different temperatures.

[0176]

[0177] As can be seen from Table 3, as the temperature continues to decrease, the fully vulcanized sealant still has a smooth surface, no cracks or loss of adhesion, and excellent low-temperature resistance.

[0178] 3. Heat resistance air circulation performance test

[0179] The sealant prepared in Example 6 was used to prepare Type I tensile specimens according to GB / T 528-2009. After complete vulcanization, the specimens were placed under different hot air cycles (127℃×4h→160℃×40min→180℃×1h) to test their elongation at break. The test results are shown in Table 4.

[0180] Table 4. Determination of Elongation at Break under Different Thermal Cycles

[0181] Number of thermal cycles 1 time 2 times 3 times 4 times 5 times 6 times Elongation at break / % 479 443 398 336 257 228

[0182] As shown in Table 4, the elongation at break gradually decreases with the increase of the number of thermal cycles, but the elongation at break is still greater than 200% after six hot air cycles, indicating excellent high-temperature hot air cycle resistance.

[0183] It should be noted that the above performance tests were conducted using the modified polysulfide sealing rubber prepared in Examples 1 to 6. When the raw materials, mass ratios, and preparation parameters in the examples are replaced, the resulting two-component modified polysulfide sealant for bonding surfaces also exhibits the same or similar performance. It improves the elongation at break of the polysulfide sealant under extreme environments, has excellent resistance to deformation, avoids cracking, shrinkage, and adhesion failure of the sealant layer, and can greatly enhance the sealing performance of the bonding surface.

[0184] The above are several preferred embodiments of the preparation method of the present invention, but they should not be regarded as limitations on the technical solutions protected by the present invention. Any simple modifications, changes and equivalent changes made based on the technical concept of the present invention, and all alternative solutions obtained by those skilled in the art without creative labor, should fall within the protection scope of the present invention.

Claims

1. A two-component modified polysulfide sealant for bonding surfaces, characterized in that, It is made from component A and component B in a mass ratio of 100:(8-12); The first component comprises the following raw materials in parts by weight: 95-105 parts modified polysulfide rubber, 10-20 parts functional filler, 0.5-1 part coupling agent, 0.5-1 part binder, and 0.5-1 part modifier; The modified polysulfide rubber is made of polysulfide rubber and a modifier; the modifier is one of bis(2-chloroethyl) ether, 1,2-dichloroethane and bis(chloromethyl)dimethylsilane; The B component comprises the following raw materials in parts by weight: 55-65 parts of metal oxide, 25-35 parts of plasticizer, 0.5-1 part of accelerator, and 0.5-1 part of regulator.

2. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The functional filler is prepared by mixing precipitated SiO2 and nano SiO2 in a mass ratio of (35-45):(10-20); the particle size of the nano SiO2 is 50nm to 150nm.

3. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The coupling agent is one or both of silane coupling agents and phthalate coupling agents; When the coupling agent is a silane coupling agent and a phthalate coupling agent, the mass ratio of the silane coupling agent to the phthalate coupling agent is (30-40):(5-10).

4. The two-component modified polysulfide sealant for bonding surfaces according to claim 3, characterized in that, The silane coupling agent is any one of vinyltriethylsilane, γ-glycidoxypropyltrimethylsilane, γ-mercaptopropyltriethoxysilane and γ-aminopropyltriethoxysilane; The phthalate coupling agent is any one of isopropyltris(isostearoyl) phthalate, isopropyltris(dodecylbenzenesulfonyl) phthalate, and isopropyltris(methacryloyloxy) phthalate.

5. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The adhesive is epoxy resin; the modifier in both component A and component B is stearic acid.

6. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The metal oxide is any one of lead dioxide, manganese dioxide, and zinc oxide.

7. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The plasticizer is any one of dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and tributyl acetylacetonate.

8. The two-component modified polysulfide sealant for bonding surfaces according to claim 1, characterized in that, The accelerator is one or two of tetramethylthiuram disulfide, diphenylguanidine, 2-mercaptobenzothiazole and dibenzothiazole disulfide; When the accelerator is tetramethylthiuram disulfide and 2-mercaptobenzothiazole, the mass ratio of tetramethylthiuram disulfide to 2-mercaptobenzothiazole is (10-15):(3-5); When the accelerator is tetramethylthiuram disulfide and dibenzothiazole disulfide, the mass ratio of tetramethylthiuram disulfide to dibenzothiazole disulfide is (10-15):(3-5).

9. A method for preparing a two-component modified polysulfide sealant for bonding surfaces as described in claim 1, characterized in that, The preparation method includes the following steps: S1. Preparation of modified polysulfide rubber After adding a modifier to polysulfide rubber, the mixture is heated to 70-90℃ and stirred for 72-96 hours to obtain modified polysulfide rubber. S2, Preparation of component A Take the modified polysulfide rubber from step S1 according to the mass fraction, and then add the functional filler, coupling agent, adhesive and regulator in sequence; stir for 10 minutes after each addition of raw material to obtain component A; S3. Preparation of component B The metal oxide, plasticizer, accelerator and regulator are coarsely mixed according to the mass ratio, and then kneaded 3 to 6 times using a three-roll mill to obtain component B; S4. Preparation of two-component modified polysulfide sealant for bonding surfaces After coarsely mixing components A and B according to their mass ratio, the mixture is then kneaded 3 to 6 times using a three-roll mill to obtain the final product.

10. The application of the two-component modified polysulfide sealant for bonding surfaces as described in claim 1 in improving elongation at break and resistance to deformation.

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