Composite expansion sealing material as well as preparation method and application thereof

Abstract

The invention provides a composite expansion sealing material as well as a preparation method and application thereof, and belongs to the technical field of pipeline sealing. The composite expansion sealing material comprises a carrier layer and a composite sealing paste layer coated on the carrier layer, the composite sealing paste layer is prepared from the following raw materials in parts by mass: 30-65 parts of a continuous phase resin matrix; 1-40 parts of a modifier; 10 to 65 parts of an expansion component; 1-15 parts of reinforced fibers; 1-40 parts of a toughening agent; 1-30 parts of a conditioning agent; and the expansion component is organic polymer water-absorbent resin and hydratable layered silicate minerals. The sealing material is a preformed thread sealing material which has initial filling property, self-expands to enhance sealing after encountering a working medium, and has good construction flexibility and adhesive force.

Description

Technical Field

[0001] This invention relates to the field of pipeline sealing technology, and in particular to a composite expansion sealing material, its preparation method, and its application. Background Technology

[0002] Pipeline threaded connections are one of the most common detachable connection methods in the petroleum, chemical, and water supply and drainage industries. Their sealing performance directly affects the safety and reliability of the entire pipeline system. Currently, commonly used thread sealing materials mainly include PTFE raw material tape and various liquid sealants / pastes.

[0003] PTFE raw tape possesses excellent chemical stability and non-stick properties, but it lacks expansion properties, and its sealing relies on the filling effect of winding. This requires precise handling techniques and exhibits poor resistance to vibration and pressure pulsation, making it prone to loosening and leakage under long-term operating conditions. While liquid sealants or anaerobic adhesives can form a denser sealing layer, they have drawbacks such as curing time requirements, difficulty in disassembly, sensitivity to thread cleanliness, and potential chemical compatibility issues.

[0004] Hydrated layered silicate minerals and superabsorbent polymers, due to their significant volume expansion upon contact with water or oil, have been explored for use in sealing applications. However, using these powdered expandable materials alone or in simple mixtures presents problems such as weak adhesion to the matrix, easy detachment, poor initial sealing performance, and low mechanical strength, making them difficult to apply directly to pipe threaded joints where both initial sealing and durability are critical. Summary of the Invention

[0005] The purpose of this invention is to provide a composite expansion sealing material, its preparation method, and its application. The composite expansion sealing material is a thread sealing material that has initial filling properties, self-expanding and enhancing sealing upon contact with the working medium, and good construction flexibility and adhesion.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a composite expansion sealing material, comprising a carrier layer and a composite sealing paste layer coated on the carrier layer; The composite sealing paste layer is prepared from the following raw materials in parts by weight: Continuous phase resin matrix 30-65 parts; modifier 1-40 parts; swelling component 10-65 parts; reinforcing fiber 1-15 parts; toughening agent 1-40 parts; regulator 1-30 parts; The expanding component is an organic polymer water-absorbing resin and a hydrated layered silicate mineral.

[0007] Preferably, the continuous phase resin matrix comprises two or three of polyalkylene glycols, polyols, and polyalkylene polyol ethers.

[0008] Preferably, the modifier includes one or more of liquid polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and methyl-terminated polydimethylsiloxane.

[0009] Preferably, the hydrated layered silicate minerals include one or more of bentonite, montmorillonite, saponite, lithium saponite, sepiolite, and attapulgite; The organic superabsorbent polymer includes cross-linked sodium polyacrylate or linear sodium polyacrylate; The mass ratio of the organic superabsorbent polymer to the hydrated layered silicate mineral is 1:5~10.

[0010] Preferably, the reinforcing fiber includes one or more of aramid chopped fibers, polyphenylene sulfide chopped fibers, polypropylene chopped fibers, polyester chopped fibers, polyethylene chopped fibers, polyimide chopped fibers, flax fibers, and bamboo fibers.

[0011] Preferably, the toughening agent includes one or more of polyethylene powder, polytetrafluoroethylene powder, polyvinyl chloride powder, polypropylene powder, polyester powder, polystyrene powder, and polyimide powder.

[0012] Preferably, the modifier includes one or more of the following: polyether-modified polydimethylsiloxane leveling agent, hydrophobic fumed silica, hydrogenated castor oil, polyamide wax powder, and hydroxyethyl cellulose.

[0013] Preferably, the carrier layer is a nonwoven fabric, and the raw materials for preparing the nonwoven fabric include polyester, polypropylene, or alkali-free glass fiber, and the basis weight of the nonwoven fabric is 20~50 g / m². 2 .

[0014] This invention provides a method for preparing the composite expansion sealing material described in the above technical solution, comprising the following steps: A paste is obtained by mixing a continuous phase resin matrix, a modifier, a regulator, and a toughening agent. The paste is mixed with an expanding component and reinforcing fibers to obtain a composite sealant. The composite sealant is coated onto the surface of the carrier layer to obtain a composite expansion sealant material.

[0015] This invention provides the application of the composite expansion sealing material described in the above technical solution or the composite expansion sealing material prepared by the preparation method described in the above technical solution in pipe threaded connections.

[0016] This invention provides a composite expansion sealing material with liquid absorption expansion and toughness enhancement properties. The sealing material is easy to construct. Initially, it relies on the viscoplasticity of the resin matrix to fill the thread gap. When it comes into contact with working media such as water and oil, the expansion component can undergo controllable expansion, further compressing the sealing surface, thereby achieving a dynamic and durable sealing effect. Moreover, it can be pre-formed into a strip.

[0017] Compared with the prior art, the present invention has the following significant advantages: 1. Dual-effect sealing mechanism: Initially, the resin matrix relies on viscoplastic deformation to fill the thread gap and achieve initial sealing; when it encounters the working medium (water, oil, etc.), the two expansion components expand together to generate continuous radial pressure, which compensates for the gap changes caused by vibration, thermal expansion and contraction, etc., and achieves dynamic and durable sealing.

[0018] 2. Excellent construction performance: The composite sealant gives the sealing material good flexibility and self-adhesion, making it easy to wrap and not easy to loosen; the non-woven fabric carrier layer provides good mechanical strength and dimensional stability, facilitating construction operations.

[0019] 3. Synergistic effect of components: The continuous phase resin matrix serves as both a carrier and possesses certain hygroscopic and lubricating properties; the reinforcing effect of the reinforcing fibers avoids the fragility of traditional expanded materials. The toughening agent improves the product's cohesion and surface smoothness.

[0020] 4. Wide range of applications: By adjusting the ratio of resin matrix and expansion component, it can be adapted to pipe thread seals in various media environments such as water, oil, weak acid and weak alkali.

[0021] 5. Environmentally friendly and easy to disassemble: Compared with anaerobic adhesives, the product of this invention does not cure and can usually be removed manually during disassembly, causing minimal damage to the threads. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the composite expansion sealing tape prepared according to the present invention; wherein, 1 is the carrier layer and 2 is the composite sealing paste layer; Figure 2 This is a schematic diagram of the composite expansion sealing strip prepared according to the present invention applied to a pipe thread interface; wherein, 3 is the external thread of the pipe; 4 is the internal thread of the pipe fitting. Detailed Implementation

[0023] In this invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well known to those skilled in the art.

[0024] This invention provides a composite expansion sealing material, comprising a carrier layer and a composite sealing paste layer coated on the carrier layer; The composite sealing paste layer is prepared from the following raw materials in parts by weight: Continuous phase resin matrix 30-65 parts; modifier 1-40 parts; swelling component 10-65 parts; reinforcing fiber 1-15 parts; toughening agent 1-40 parts; regulator 1-30 parts; The expanding component is an organic polymer water-absorbing resin and a hydrated layered silicate mineral.

[0025] The composite expansion sealing material provided by the present invention includes a composite sealing paste layer. By mass, the raw materials of the composite sealing paste layer contain 30 to 65 parts of continuous phase resin matrix, preferably 31.5 to 38 parts, and more preferably 33.5 to 35 parts.

[0026] In this invention, the continuous phase resin matrix preferably comprises two or three of polyalkylene glycols, polyols, and polyalkylene polyol ethers. This invention does not impose specific limitations on the proportions of different types of continuous phase resin matrices; adjustments can be made as needed.

[0027] In this invention, the polyalkylene glycol is preferably at least one of polyethylene glycol, polypropylene glycol, and ethylene oxide-propylene oxide copolymer (EO-PO block copolymer); The polyol is preferably at least one of glycerol, ethylene glycol, propylene glycol, and sorbitol; The polyalkylene polyol ether is preferably at least one of polyethylene glycol monomethyl ether and polyethylene glycol dimethyl ether.

[0028] As a preferred embodiment of the present invention, the continuous phase resin matrix is ​​preferably a mixture of polyethylene glycol, glycerol and polypropylene glycol; wherein, the average molecular weight of the polyethylene glycol is preferably 200-1000, more preferably polyethylene glycol 400, and the average molecular weight of the polypropylene glycol is preferably 200-1000, more preferably polypropylene glycol 1000; the mass ratio of polyethylene glycol, glycerol and polypropylene glycol is preferably (15-20):(10-15):(2.5-5.5), more preferably (19-20):(10-12.5):(2.7-3.5).

[0029] The continuous phase resin matrix of this invention is a polymer or oligomer that is liquid, semi-solid, or waxy solid at room temperature, can be uniformly mixed with all solid raw materials such as the expanding component, reinforcing fibers, and toughening agents to form a stable paste system, and contains polar hydroxyl groups on its molecular chain to provide cohesion and interfacial wettability. This mixed resin matrix is ​​a viscous paste at room temperature, possessing good initial tack, plastic deformation ability, and filler encapsulation properties, effectively adhering to the carrier and filling thread gaps. The continuous phase resin matrix of this invention is used to support solid fillers, provide necessary thixotropy, and form a uniform sealing film during thread tightening.

[0030] Based on the mass fraction of the continuous phase resin matrix, the modifier in the raw materials of the composite sealing paste layer is 1 to 40 parts, preferably 5 to 20 parts, more preferably 8 to 15 parts, and even more preferably 10 to 12 parts.

[0031] In this invention, the modifier preferably includes one or more of liquid polydimethylsiloxane (PDMS), hydroxyl-terminated polydimethylsiloxane, and methyl-terminated polydimethylsiloxane, more preferably liquid polydimethylsiloxane (PDMS).

[0032] In this invention, the liquid polydimethylsiloxane has a CAS registration number of 63148-62-9, a viscosity in the range of 1000~100000 mPas at 25°C, and volatile substances ≤0.1%.

[0033] In this invention, the molecular weight range of the hydroxyl-terminated polydimethylsiloxane or the methyl-terminated polydimethylsiloxane is preferably 10,000-500,000, and the degree of polymerization n is preferably 135-6750.

[0034] The modifier described in this invention plays a multifunctional role in the system, including providing lubrication and dispersion during the production process, improving product stability during the storage stage, imparting slipperiness and ease of operation during construction, and exhibiting flexible and uniform sealing performance in the resulting composite expansion sealing material.

[0035] Based on the mass fraction of the continuous phase resin matrix, the expansion component in the raw material of the composite sealing paste layer is 10-65 parts, preferably 32.5-43 parts, and more preferably 39-41.8 parts; the expansion component is an organic polymer water-absorbing resin and a hydrated layered silicate mineral.

[0036] In this invention, the hydrated layered silicate mineral preferably includes one or more of bentonite, montmorillonite, saponite, lithium saponite, sepiolite, and attapulgite, with sodium-based bentonite being more preferred. When the hydrated layered silicate mineral comprises two or more of the above-mentioned types, this invention does not impose any particular limitation on the proportion of different types of hydrated layered silicate minerals, and any proportion is acceptable. The hydrated layered silicate minerals of this invention are minerals with a layered crystal structure and hydration expansion function, belonging to the silicate category with montmorillonite as the main mineral.

[0037] In this invention, the organic superabsorbent polymer preferably includes cross-linked sodium polyacrylate or linear sodium polyacrylate, with CAS registration number 9003-04-7.

[0038] In this invention, the mass ratio of the organic superabsorbent polymer to the hydrated layered silicate mineral is preferably 1:5~10, more preferably 1:6.3~8.8.

[0039] In the expansion component of this invention, the organic polymer water-absorbing resin is the main active ingredient, which ensures an immediate sealing effect through high expansion rate and rapid water absorption; the hydrated layered silicate mineral is the synergistic active ingredient, which provides long-lasting expansion pressure and synergistically optimizes the overall performance of the system in both dry and wet conditions.

[0040] Based on the mass fraction of the continuous phase resin matrix, the raw material of the composite sealing paste layer contains 1 to 15 parts of reinforcing fiber, preferably 2 to 10 parts, and more preferably 3 to 5 parts; In this invention, the reinforcing fiber preferably includes one or more of the following: aramid chopped fibers, polyphenylene sulfide chopped fibers, polypropylene chopped fibers, polyester chopped fibers, polyethylene chopped fibers, polyimide chopped fibers, flax fibers, and bamboo fibers. When the reinforcing fiber is two or more of the above, this invention does not have a special limitation on the ratio of different types of reinforcing fibers, and any ratio is acceptable.

[0041] In this invention, the length of the reinforcing fiber is preferably 0.3~3 mm, more preferably 0.5~2 mm. This invention does not impose any special limitations on other specifications of the reinforcing fiber; commercially available products well-known in the art are acceptable. This invention utilizes the reinforcing fiber to form a three-dimensional network structure, significantly improving the tensile strength and tear resistance of the sealing tape and preventing breakage during construction.

[0042] Based on the mass fraction of the continuous phase resin matrix, the toughening agent in the raw materials of the composite sealing paste layer is 1 to 40 parts, preferably 5 to 20 parts, and more preferably 6.5 to 7.5 parts.

[0043] In this invention, the toughening agent preferably includes one or more of polyethylene (PE) powder, polytetrafluoroethylene (PTFE) powder, polyvinyl chloride (PVC) powder, polypropylene (PP) powder, polyester (PET) powder, polystyrene (PS) powder, and polyimide (PI) powder. When the toughening agent is two or more of the above, this invention does not have a special limitation on the ratio of different types of toughening agents, and any ratio is acceptable.

[0044] In this invention, the powder particle size of the toughening agent is preferably 50-5000 mesh, more preferably 300-3000 mesh, and even more preferably 1000-1500 mesh. The toughening agent of this invention functions to systematically improve and optimize the mechanical properties, tribological properties, workability, and long-term reliability of the sealing strip by introducing solid particles with specific properties.

[0045] Based on the mass fraction of the continuous phase resin matrix, the raw materials of the composite sealing paste layer contain 1 to 30 parts of regulator, preferably 5 to 15 parts, more preferably 7.8 to 12 parts, and even more preferably 8.2 to 10 parts.

[0046] In this invention, the regulator preferably includes one or more of the following: polyether-modified polydimethylsiloxane leveling agent, hydrophobic fumed silica, hydrogenated castor oil (e.g., Thixatrol ST), polyamide wax powder (e.g., DISPARLON 6900-20X, Crayvallac SLT), and hydroxyethyl cellulose (HEC); when the regulator is two or more of the above, this invention does not have a special limitation on the ratio of different types of regulators, and any ratio is acceptable.

[0047] This invention utilizes regulators to achieve the following synergistic effects: 1) Adjusting rheological and construction properties: Fumed silica, hydrogenated castor oil and polyamide wax powder are highly efficient thixotropic agents and thickeners, which can adjust the consistency of the system and significantly optimize the rheological properties of the composite sealant, giving it good anti-sagging and paste stability, making it easy to form during coating, easy to apply force during construction and wrapping and non-sticky.

[0048] 2) Improved interface and dispersion performance: Polyether-modified polydimethylsiloxane and other organosilicon surfactants can effectively reduce the surface tension of the system, promote the wetting and encapsulation of solid raw materials such as expansion components and reinforcing fibers by liquid base material, ensure uniform dispersion of each component, avoid agglomeration, and thus improve the consistency and stability of the paste.

[0049] 3) Enhanced system stability: The combined use of regulators can form a stable three-dimensional network structure or gel system, preventing solid particles from settling and stratifying during storage, and ensuring the long-term uniformity of product performance.

[0050] 4) Optimize the performance of the final product: The combined effect of the above-mentioned actions results in a sealing material with suitable flexibility, cohesive strength and surface properties, which not only facilitates construction operations, but also ensures the formation of a uniform, dense and firmly adhered sealing layer in the thread gap, providing a stable matrix environment for initial sealing and subsequent media-triggered expansion.

[0051] In this invention, the carrier layer is preferably a nonwoven fabric, and the raw materials for preparing the nonwoven fabric preferably include polyester, polypropylene, or alkali-free glass fiber. The basis weight of the nonwoven fabric is preferably 20~50 g / m². 2 More preferably 25~30 g / m 2This invention does not impose any special limitations on the weaving process (such as spunbond, meltblown, hydroentangling, etc.) and fabric structure or source of the nonwoven fabric. Those skilled in the art can conventionally select commercially available products based on the required strength, flexibility and cost.

[0052] This invention provides a method for preparing the composite expansion sealing material described in the above technical solution, comprising the following steps: A paste is obtained by mixing a continuous phase resin matrix, a modifier, a regulator, and a toughening agent. The paste is mixed with an expanding component and reinforcing fibers to obtain a composite sealant. The composite sealant is coated onto the surface of the carrier layer to obtain a composite expansion sealant material.

[0053] In this invention, the preferred method for preparing the composite sealant is as follows: The continuous phase resin matrix and the modifier were mixed at room temperature and stirred until a homogeneous and transparent liquid base was formed. Different addition methods are adopted depending on the physical form and function of the selected regulator: When the modifier is a liquid (such as a polyether-modified polydimethylsiloxane leveling agent), it is added together with the modifier to prepare a liquid base material, and then stirred until homogeneous.

[0054] When the regulator needs to be pre-dispersed (such as hydroxyethyl cellulose), the regulator is pre-dispersed in water to form a uniform solution. After dispersion is complete, it is added together with the modifier to prepare the liquid base material.

[0055] When the regulator is a solid powder (such as hydrophobic fumed silica, polyamide wax powder, hydrogenated castor oil): after the liquid base material is prepared, the regulator is added together with the toughening agent and the expansion component, or added at a specific stage (such as when adjusting the rheology) and dispersed at high speed.

[0056] As a preferred general embodiment, the method for preparing the composite sealant includes the following steps: A continuous phase resin matrix is ​​mixed with a modifier (and a liquid regulator) to obtain a liquid base material; The liquid base material is mixed with solid modifiers (such as hydrophobic fumed silica, polyamide wax powder, hydrogenated castor oil) and toughening agents, or added step by step according to the type of modifier, and dispersed by stirring to obtain a paste. The paste is mixed with an expanding component and reinforcing fibers to obtain a composite sealant with a uniform texture and no lumps.

[0057] As a specific embodiment of the present invention, taking the simultaneous inclusion of multiple types of regulators as an example, the preferred preparation method is: Disperse hydroxyethyl cellulose in deionized water and stir until completely dissolved to prepare a 5% (w / w) aqueous solution of hydroxyethyl cellulose. Add the continuous phase resin matrix to a planetary mixer and stir for 10 to 45 minutes at room temperature (25±5℃) and a speed of 100 to 300 rpm to form a homogeneous and transparent mixture. Then, under continuous low-speed stirring, add the modifier and regulator (polyether-modified polydimethylsiloxane leveling agent), and continue stirring for 15-30 minutes to form a uniform liquid base material; While stirring, add toughening agent and expansion component to the liquid base material in sequence, and gradually increase the stirring speed to 1000~1500 rpm and stir for 20~60 minutes to completely disperse the solid powder; Then add the pre-prepared aqueous solution of hydroxyethyl cellulose and continue stirring for 10-30 minutes; Adjust the rotation speed to 500~1000 rpm, add the regulator hydrophobic fumed silica and stir for 15~45 min; evenly sprinkle the reinforcing fiber into the resulting mixture and stir for 20~60 min until all solid components are fully wetted and evenly dispersed, forming a stable three-dimensional network structure without clumping, thus obtaining the composite sealant.

[0058] It should be noted that when the type or combination of regulators changes, those skilled in the art can reasonably adjust the order of addition and mixing method based on the above preparation method according to their physical form (liquid, solid or pre-dispersible) and function (leveling, thixotropy, thickening) to still obtain the composite sealing paste described in this invention.

[0059] After obtaining the composite sealant, the present invention preferably applies the composite sealant to the surface of a continuously moving carrier layer by means of doctor blade coating, roller coating, or slot extrusion coating, wherein the coating amount is preferably 150~400 g / m². 2 (Wet weight), more preferably 200~300 g / m 2 .

[0060] The present invention preferably adjusts the coating speed and coating thickness according to the production conditions. The coating speed is preferably 3~10 m / min, more preferably 5 m / min, and the coating thickness is preferably 0.2 mm.

[0061] In this invention, when the composite sealant contains volatile components (such as water or low-boiling-point solvents) (e.g., using solvent-containing raw materials such as HEC aqueous solution), drying is required after coating. The preferred drying temperature is 60-120°C, and the preferred drying time is 1-5 minutes to remove the volatile components. When it does not contain volatile components, drying is not required after coating, and subsequent applications can proceed directly. After coating and drying as needed, a dry or semi-dry composite expansion sealant is obtained. The composite expansion sealant can be wound into rolls and stored as an intermediate product. In use, it can be cut into sealing strips of a certain width as needed.

[0062] This invention provides the application of the composite expansion sealing material described in the above-described technical solution or the composite expansion sealing material prepared by the preparation method described in the above-described technical solution in pipe threaded connections, such as... Figure 2 As shown.

[0063] In this invention, the composite expansion sealing material can be processed into different physical forms depending on the application scenario. For example, it can be pre-formed into continuous rolls and cut into sealing strips of a certain width according to usage requirements for use in sealing pipe threads; it can also be molded or cut into sheets, rings, or gaskets as needed for sealing flat flanges, threaded joints of specific specifications, or inspection holes. Among these, the pre-formed roll form, which can be cut on-site, is the preferred application form for pipe threaded connections.

[0064] When the composite expansion sealing material is in strip form, the present invention preferably cuts the composite expansion sealing material to the required width (preferably 15mm), winds it into a disc, and packages it to obtain the finished sealing strip, such as... Figure 1 As shown.

[0065] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0066] Unless otherwise specified, the experimental methods described in the various embodiments of this invention are conventional methods; unless otherwise specified, the reagents and raw materials described below are all commercially available.

[0067] Example 1

[0068] In the composite expansion sealing material provided in this embodiment, the carrier layer is a commercially available polyester PET spunbond nonwoven fabric (30 g / m²). 2 The raw material components for preparing the composite sealant layer are shown in Table 1. Table 1. Raw materials for preparing the composite sealant layer in Example 1

[0069] footnote: It is a 5wt% aqueous solution of hydroxyethyl cellulose (HEC).

[0070] Preparation method: 1. Preparing a hydroxyethyl cellulose aqueous solution: Disperse hydroxyethyl cellulose in deionized water and stir until completely dissolved to prepare a 5% (w / w) hydroxyethyl cellulose solution for later use.

[0071] 2. Preparation of liquid base material: In a planetary mixer, polyethylene glycol 400, glycerin and polypropylene glycol 1000 are added in sequence and stirred for 15 minutes at room temperature (25℃) and 300 rpm to form a uniform and transparent mixture; then, under continuous stirring, PDMS modifier and polyether modified polydimethylsiloxane leveling agent are added and stirred for another 15 minutes to form a uniform liquid base material.

[0072] 3. Preparation of composite sealant: Under continuous stirring, polyethylene powder, sodium bentonite, and cross-linked sodium polyacrylate are added sequentially to the liquid base material. After the addition is complete, the stirring speed is gradually increased to 1000 rpm and stirred continuously at this speed for 20 min. Then, a pre-prepared hydroxyethyl cellulose (HEC) aqueous solution is added to the system, and stirring continues for 10 min. Afterward, the stirring speed is reduced to 500 rpm, hydrophobic fumed silica is added as a regulator, and stirring continues for 15 min. Then, aramid chopped fibers are evenly sprinkled into the mixture in portions, and stirring continues for 20 min until the fibers are evenly dispersed in the sealant, forming a stable three-dimensional network structure without visible clumping, resulting in a homogeneous composite sealant.

[0073] 4. Sealing tape preparation: Polyester PET spunbond nonwoven fabric (30 g / m²) was used. 2 Using a comma-shaped doctor blade coater as the substrate, the above-mentioned composite sealant was uniformly coated at a coating speed of 5 m / min, a coating thickness of 0.2 mm, and a coating amount of 150 g / m. 2 After coating, dry at 100℃ for 5 minutes, cut into 15 mm wide rolls, and wind into coils to obtain the sealing tape.

[0074] Example 2

[0075] The only difference from Example 1 is that the raw material composition for preparing the composite sealing paste layer is shown in Table 2: Table 2. Raw materials for the preparation of the composite sealant layer in Example 2.

[0076] The preparation method is the same as in Example 1.

[0077] Example 3

[0078] The only difference from Example 1 is that the raw material composition for preparing the composite sealing paste layer is shown in Table 3: Table 3. Raw materials for the preparation of the composite sealant layer in Example 3.

[0079] The preparation method is the same as in Example 1.

[0080] Example 4

[0081] The only difference from Example 1 is that the raw material composition for preparing the composite sealing paste layer is shown in Table 4: Table 4. Raw materials for the preparation of the composite sealant layer in Example 4.

[0082] The preparation method is the same as in Example 1.

[0083] Comparative Example 1

[0084] Commercially available high-quality polytetrafluoroethylene (PTFE) raw material tape is sourced from Daikin Polyflon™ PTFE sealing tape from Japan, with a width of 15mm and a length of 10m / roll.

[0085] Comparative Example 2

[0086] The raw material composition for preparing non-expanding conventional sealant is shown in Table 5: Table 5. Raw materials for preparing the sealant in Comparative Example 2.

[0087] Comparative Example 3

[0088] The only difference between this comparative example and Example 1 is that the expansion component did not contain cross-linked sodium polyacrylate and reinforcing fibers. The specific formulation is shown in Table 6.

[0089] Table 6. Raw materials for preparing the composite sealant layer in Comparative Example 3.

[0090] Performance testing

[0091] 1. Sealing performance test

[0092] To verify the sealing performance of the composite expansion sealing material of the present invention, the sealing tapes prepared in Examples 1 to 4, as well as Comparative Example 1 (commercially available PTFE raw material tape), Comparative Example 2 (non-expanding sealant) and Comparative Example 3 (without sodium polyacrylate and reinforcing fibers) were subjected to the following performance tests.

[0093] The testing methods are designed in accordance with relevant industry standards and in combination with actual operating conditions.

[0094] 1) Initial sealing performance test

[0095] Test method: Wrap the sealing material around the standard external thread (G1 / 2), install it onto the internal thread connector, and tighten it to the standard torque (15 N·m) using a torque wrench. Immediately after assembly, install it onto the air pressure test bench, gradually apply air pressure, and record the pressure value when leakage occurs as the initial sealing pressure.

[0096] Test medium: dry compressed air.

[0097] Results: As shown in Table 7 below, Examples 1-4 of the present invention contain a continuous phase resin matrix with initial tack and plasticity, and the organic polymer water-absorbing resin and reinforcing fibers can better fill the thread gaps. The initial sealing pressure is significantly higher than that of Comparative Example 1 (PTFE raw material tape), Comparative Example 2 (non-expanding putty), and Comparative Example 3 (lacking reinforcing fibers and some expanding components).

[0098] 2) Self-reinforcing sealing performance test after medium triggering

[0099] Test method: For samples that have completed the initial sealing test and have not leaked, apply the working medium (water or hydraulic oil) to the threaded connection and let stand for 24 hours to allow the expansion components to fully swell. Then, perform a pneumatic pressure test again and record the leakage pressure.

[0100] Test media: water (for water-based conditions) and hydraulic oil ISOVG32 (for oil-based conditions).

[0101] Results: As shown in Table 7 below, Examples 1-4 of the present invention contain a composite expanding component of organic superabsorbent polymer and layered silicate minerals, which expands in volume upon contact with the medium, generating continuous radial pressure and significantly increasing the sealing pressure. Comparative Example 1 has no expanding properties, and Comparative Example 2 has no active expanding component; its sealing pressure does not increase and may even decrease due to medium impregnation. Although Comparative Example 3 retains some expanding properties, its expanding effect and sealing enhancement are significantly lower than those of the Examples due to the lack of synergistic expanding components and reinforcing fibers.

[0102] 2. Vibration-pressure pulsation cycle durability test

[0103] Test method: Install the sealing joint on a vibration testing machine and connect it to a hydraulic pulse testing bench. Apply pressure pulsation at a frequency of 1 Hz within a pressure range of 0.5-2 MPa, while simultaneously applying axial vibration at a frequency of 10 Hz and an amplitude of ±0.5 mm, for 1000 cycles. After the test, check for leaks and measure the seal pressure retention rate.

[0104] Results: As shown in Table 7 below, Examples 1-4 of the present invention maintained good sealing integrity under vibration and pressure changes due to the three-dimensional network formed by reinforcing fibers and the increased cohesion by toughening agents. Comparative Example 1 was prone to loosening, and Comparative Example 2 lacked strength, both showing early leakage. Comparative Example 3, lacking reinforcing fibers and having insufficient cohesion, showed slight leakage after vibration.

[0105] 3. Construction performance evaluation

[0106] Flexibility: Hand feel assessment, whether it breaks easily during winding, and whether it easily conforms to the thread.

[0107] Adhesion: the peeling between the coating layer and the nonwoven carrier, and the initial adhesion to the threaded metal after wrapping.

[0108] Results: As shown in Table 7 below, Examples 1-4 of the present invention exhibit good bonding between the nonwoven fabric carrier and the paste layer, resulting in flexibility, resistance to breakage, moderate self-adhesion, and convenient construction. Comparative Example 1 lacks adhesiveness and relies entirely on winding tension; Comparative Example 2 has a loose paste that is prone to detachment during construction; the paste layer of Comparative Example 3, due to the absence of reinforcing fibers in its formulation, has relatively insufficient cohesive strength. Under stress, this layer is prone to cohesive failure, resulting in inferior overall performance after construction compared to the examples.

[0109] Table 7 Performance data of Examples 1-4 and Comparative Examples 1-3

[0110] Test results show that the composite expansion sealing material (Examples 1-4) provided by this invention possesses excellent initial filling and sealing capabilities, self-expanding and enhanced sealing capabilities upon contact with the working medium, and good vibration and pressure cycle durability. Its overall performance is significantly superior to traditional PTFE raw material tape (Comparative Example 1) and non-expanding sealing putty (Comparative Example 2). Furthermore, the test results of Comparative Example 3 verify the crucial role of the synergistic effect of the organic superabsorbent polymer and reinforcing fibers in improving sealing performance. This invention is particularly suitable for sealing pipe threads under various media conditions such as water, oil, and gas. It is also convenient to construct and easy to disassemble, demonstrating significant technical advantages and application prospects.

[0111] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite expansion sealing material, characterized in that, Includes a carrier layer and a composite sealant layer coated on the carrier layer; The composite sealing paste layer is prepared from the following raw materials in parts by weight: Continuous phase resin matrix 30-65 parts; modifier 1-40 parts; swelling component 10-65 parts; reinforcing fiber 1-15 parts; toughening agent 1-40 parts; regulator 1-30 parts; The expanding component is an organic polymer water-absorbing resin and a hydrated layered silicate mineral.

2. The composite expansion sealing material according to claim 1, characterized in that, The continuous phase resin matrix includes two or three of polyalkylene glycols, polyols, and polyalkylene polyol ethers.

3. The composite expansion sealing material according to claim 1, characterized in that, The modifier includes one or more of liquid polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and methyl-terminated polydimethylsiloxane.

4. The composite expansion sealing material according to claim 1, characterized in that, The hydrated layered silicate minerals include one or more of bentonite, montmorillonite, saponite, lithium saponite, sepiolite, and attapulgite. The organic superabsorbent polymer includes cross-linked sodium polyacrylate or linear sodium polyacrylate; The mass ratio of the organic superabsorbent polymer to the hydrated layered silicate mineral is 1:5~10.

5. The composite expansion sealing material according to claim 1, characterized in that, The reinforcing fibers include one or more of the following: aramid chopped fibers, polyphenylene sulfide chopped fibers, polypropylene chopped fibers, polyester chopped fibers, polyethylene chopped fibers, polyimide chopped fibers, flax fibers, and bamboo fibers.

6. The composite expansion sealing material according to claim 1, characterized in that, The toughening agent includes one or more of polyethylene powder, polytetrafluoroethylene powder, polyvinyl chloride powder, polypropylene powder, polyester powder, polystyrene powder, and polyimide powder.

7. The composite expansion sealing material according to claim 1, characterized in that, The modifier includes one or more of the following: polyether-modified polydimethylsiloxane leveling agents, hydrophobic fumed silica, hydrogenated castor oil, polyamide wax powder, and hydroxyethyl cellulose.

8. The composite expansion sealing material according to claim 1, characterized in that, The carrier layer is a nonwoven fabric, and the raw materials for preparing the nonwoven fabric include polyester, polypropylene, or alkali-free glass fiber. The basis weight of the nonwoven fabric is 20~50 g / m². 2 .

9. A method for preparing the composite expansion sealing material according to any one of claims 1 to 8, characterized in that, Includes the following steps: A paste is obtained by mixing a continuous phase resin matrix, a modifier, a regulator, and a toughening agent. The paste is mixed with an expanding component and reinforcing fibers to obtain a composite sealant. The composite sealant is coated onto the surface of the carrier layer to obtain a composite expansion sealant material.

10. The application of the composite expansion sealing material according to any one of claims 1 to 8 or the composite expansion sealing material prepared by the preparation method according to claim 9 in pipe threaded connections.

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