Non-woven fabric-based composite sealing film tape with low winding layer number and adaptive to coarse threads and preparation method of non-woven fabric-based composite sealing film tape

Abstract

The invention provides a low-winding-layer-number non-woven-fabric-based composite sealing film belt matched with coarse threads and a preparation method of the low-winding-layer-number non-woven-fabric-based composite sealing film belt, and belongs to the technical field of sealing materials. The sealing film tape is prepared from the following raw materials in parts by mass: 5-65 parts of a matrix, 5-65 parts of a plasticizer, 0.1-5 parts of a modifier, 1-30 parts of composite fibers and 5-70 parts of filler. Through composite fiber reinforcement, modifier interface optimization and precise coating processes, low-layer sealing (three layers), high bite-off resistance (less than or equal to 3%) and remarkable cost saving (40%) of coarse threads are realized. The sealing film belt is suitable for coarse threads (2.0 mm) and super-coarse threads (3.0 mm), and the leakage rate is lt; the content is far lower than that of a single-fiber (3%) system and a fiber-free (8%) system.

Description

Technical Field

[0001] The present invention relates to the technical field of sealing materials, and in particular to a non-woven fabric-based composite sealing film tape with a low number of winding layers and adapted to coarse thread, and a preparation method thereof. Background Art

[0002] In pipeline engineering, the sealing performance of threaded connections directly impacts the leak-proofness, pressure resistance, and long-term stability of fluid delivery systems. While inexpensive, early sealing materials (such as hemp and lead oil) suffered from aging, poor chemical resistance, and complex construction. With the increasing diversification of pipeline materials (such as plastics and stainless steel) and fluid media (such as corrosive chemicals and high-temperature steam), traditional sealing materials are no longer able to meet the high sealing, weatherability, and environmental requirements.

[0003] Although PTFE raw tape is chemically inert and heat-resistant, it still suffers from drawbacks such as insufficient mechanical strength and a lack of adhesion. The industry has attempted improvements through fiber reinforcement, adhesive coatings, and non-woven fabric substrates, but each has its limitations.

[0004] In recent years, silicone-nonwoven fabric substrates have shown advantages: resistance to high and low temperatures (-60°C to 300°C), good chemical inertness, and three-dimensional structure that enhances fit. However, this material performs poorly in coarse thread applications. For example, in the prior art (such as CN118755445A), silicone sealing film tape is coated on non-woven fabric to form a composite film tape with excellent high and low temperature resistance and corrosion resistance. However, this technology still has the following limitations when dealing with different thread specifications:

[0005] 1. Fine thread (such as DN32~DN40, pitch 1.5mm, 16 threads per inch):

[0006] Only 3 layers of film tape are needed to achieve effective sealing, which performs well.

[0007] 2. Coarse thread (e.g. DN32-DN40, pitch 2.0mm, 11 threads per inch):

[0008] It takes 5 to 6 layers of winding to achieve the same sealing effect, and the material consumption increases significantly.

[0009] 3. Extra coarse thread (e.g. made by a threading machine, pitch 3.0mm, 6-8 threads per inch):

[0010] The silicone sealing film tape in CN118755445A needs to be wrapped 7 layers on the super coarse thread (3.0mm). Laboratory tests show that:

[0011] Construction defects: Laboratory tests show that the membrane tape bite-off rate is as high as 30% when multi-layer winding is used, and the probability of leakage channel formation increases by 5 times;

[0012] Bite-off rate: 30% (torque ≥ 30 N·m);

[0013] Leakage rate: 8% (10MPa / 72h);

[0014] Cost waste: The material consumption of a single joint increases by 140% and the construction time is extended by 80%.

[0015] Existing sealing film tapes lack adaptability to coarse threads, requiring increased wrapping to compensate for tightness. However, excessive wrapping can lead to installation difficulties and material waste. Therefore, there is an urgent need to develop a highly effective sealing material that can adapt to a wide range of thread specifications (especially coarse threads) with a low wrapping count to address these issues. Summary of the Invention

[0016] The object of the present invention is to provide a non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse threads, and a preparation method thereof, in order to solve the above-mentioned technical problems.

[0017] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0018] The present invention provides a non-woven fabric-based composite sealing film tape with a low number of winding layers and adapted to coarse thread, which is prepared from raw materials containing the following parts by mass:

[0019]

[0020] The modifier comprises γ-aminopropyltriethoxysilane and / or vinyltrimethoxysilane.

[0021] Furthermore, the composite fibers include inorganic fibers and / or organic fibers;

[0022] The inorganic fibers include one or more of glass fibers, carbon fibers, basalt fibers, and ceramic fibers; the organic fibers include one or more of aramid fibers, polyphenylene sulfide fibers, polypropylene fibers, polyester fibers, polyethylene fibers, polyimide fibers, flax fibers, and bamboo fibers.

[0023] Furthermore, the matrix is ​​silicone oil, and the silicone oil comprises one or more of liquid polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane and methyl-terminated polydimethylsiloxane.

[0024] Furthermore, the plasticizer comprises one or more of castor oil, avocado oil, rapeseed oil, peanut oil, paraffin oil, liquid paraffin oil, naphthenic oil and white oil.

[0025] Furthermore, the filler comprises one or more of silicon dioxide, calcium carbonate, talc, kaolin and bentonite.

[0026] The present invention also provides a method for preparing a non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread, comprising the following steps:

[0027] 1) mixing a base, a plasticizer, and a modifier to obtain a first mixture;

[0028] 2) adding the filler to the first mixture and mixing, and then adding the composite fiber and continuing to mix to obtain a wet paste sealant;

[0029] 3) Apply the wet paste sealant to the non-woven fabric and cut it into wide rolls.

[0030] Furthermore, in step 1), the mixing is first performed at a low speed and then at a high speed, wherein the rotation speed of the low speed mixing is 20 to 50 rpm and the time is 2 to 8 minutes; the rotation speed of the high speed mixing is 500 to 700 rpm and the time is 5 to 15 minutes.

[0031] Furthermore, in the step 2), after adding the filler, the mixing speed is 500-700 rpm, and the mixing time is 10-20 min; after adding the composite fiber, the mixing speed is 30-50 rpm, and the mixing time is 10-20 min.

[0032] Furthermore, the coating amount is 20 to 200 g / m 2 The coating thickness is 80 to 350 μm.

[0033] Beneficial effects of the present invention:

[0034] Synergistic reinforcement effect; composite fibers (such as glass fiber + carbon fiber, basalt fiber + ceramic fiber) achieve complementary rigidity and toughness through binary mixing (30:70 to 50:50 ratio), with wet initial adhesion strength reaching 0.8MPa and anti-bite performance (bite rate <5%).

[0035] The synergistic effect of different fibers optimizes stress distribution, reduces uneven stress between layers, and allows coarse threads to be wound in only 3-4 layers (traditionally 5-7 layers are required), reducing material usage by 30-50%.

[0036] The interfacial bonding strength is improved; by adding a modifier (such as γ-aminopropyltriethoxysilane), the fiber, filler and matrix are bridged through chemical bonds to form a stable Si-O-Si-NH network, and the peel strength is increased from 0.1MPa to 0.8MPa.

[0037] Optimized processing and storage performance; uniform dispersion of composite fibers reduces system viscosity by 15-20% (measured by Brookfield viscometer), reducing the risk of thermal degradation during high-speed dispersion.

[0038] The storage stability was significantly improved (no delamination for 7 days), while the single fiber and fiber-free systems showed slight sedimentation and >30% sedimentation, respectively.

[0039] Wide adaptability; suitable for coarse (2.0mm) and super coarse threads (3.0mm), leakage rate <1%, much lower than single fiber (3%) and fiber-free (8%) systems. DETAILED DESCRIPTION

[0040] The present invention provides a non-woven fabric-based composite sealing film tape with a low number of winding layers and adapted to coarse thread, which is prepared from raw materials containing the following parts by mass:

[0041]

[0042] The modifier comprises γ-aminopropyltriethoxysilane and / or vinyltrimethoxysilane.

[0043] In the present invention, the content of the matrix is ​​preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass.

[0044] In the present invention, the content of the plasticizer is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass.

[0045] In the present invention, the content of the modifier is preferably 1 to 4 parts by mass, more preferably 2 to 3 parts by mass.

[0046] In the present invention, the content of the composite fiber is preferably 2 to 25 parts by mass, more preferably 5 to 20 parts by mass.

[0047] In the present invention, the content of the filler is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass.

[0048] In the present invention, the modifier is preferably γ-aminopropyltriethoxysilane, CAS registration number 919-30-2. The CAS registration number of the vinyltrimethoxysilane is 2768-02-7.

[0049] In the present invention, the composite fibers include inorganic fibers and / or organic fibers;

[0050] The inorganic fibers include one or more of glass fibers, carbon fibers, basalt fibers and ceramic fibers, preferably one or more of glass fibers, carbon fibers and basalt fibers; the organic fibers include one or more of aramid fibers, polyphenylene sulfide fibers, polypropylene fibers, polyester fibers, polyethylene fibers, polyimide fibers, linen fibers and bamboo fibers, preferably one or more of aramid fibers, polyphenylene sulfide fibers, polypropylene fibers and polyester fibers.

[0051] In the present invention, the composite fiber is obtained by mixing two fibers, and the mass ratio of the mixed fibers is 30:70 to 50:50. The complementary rigidity and toughness are achieved through mixing, and the tensile strength and anti-bite performance are significantly improved.

[0052] In the present invention, the fibers are used after being pretreated, and commercially available fiber bundles are cut into pieces of 1-3 mm using a rotary blade cutter at a cutting speed of 200-500 rpm; the coarse thread is preferably 2-3 mm.

[0053] In the present invention, the matrix is ​​silicone oil, which comprises one or more of liquid polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane and methyl-terminated polydimethylsiloxane, preferably hydroxyl-terminated polydimethylsiloxane or methyl-terminated polydimethylsiloxane.

[0054] In the present invention, the CAS registration number of the liquid silicone oil is 63148-62-9, the viscosity at 25° C. is in the range of 1000 mPas to 100000 mPas, and the volatile matter content is ≤0.1%.

[0055] In the present invention, the molecular weight of the hydroxyl-terminated polydimethylsiloxane or the methyl-terminated polydimethylsiloxane is in the range of 10,000-500,000, and the degree of polymerization n is 135-6,750.

[0056] In the present invention, the plasticizer comprises one or more of castor oil, avocado oil, rapeseed oil, peanut oil, paraffin oil, liquid paraffin oil, naphthenic oil and white oil, preferably paraffin oil, liquid paraffin oil, naphthenic oil or white oil.

[0057] In the present invention, the filler comprises one or more of silicon dioxide, calcium carbonate, talc, kaolin and bentonite, preferably nano silicon dioxide, calcium carbonate or talc.

[0058] The present invention also provides a method for preparing a non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread, comprising the following steps:

[0059] 1) mixing a base, a plasticizer, and a modifier to obtain a first mixture;

[0060] 2) adding the filler to the first mixture and mixing, and then adding the composite fiber and continuing to mix to obtain a wet paste sealant;

[0061] 3) Apply the wet paste sealant to the non-woven fabric and cut it into wide rolls.

[0062] In the present invention, in the step 1), the mixing is first low-speed mixing and then high-speed mixing, the low-speed mixing speed is 20-50 rpm, preferably 30-40 rpm; the time is 2-8 min, preferably 5 min; the high-speed mixing speed is 500-700 rpm, preferably 600 rpm; the time is 5-15 min, preferably 10 min.

[0063] In the present invention, in step 2), the mixing speed after adding the filler is 500-700 rpm, preferably 600 rpm; the time is 10-20 min, preferably 15 min; the mixing speed after adding the composite fiber is 30-50 rpm, preferably 40 rpm; the time is 10-20 min, preferably 15 min.

[0064] In the present invention, the coating amount is 20 to 200 g / m 2 , preferably 50 to 150 g / m 2 , more preferably 30 to 60 g / m 2 ; The coating thickness is 80 to 350 μm, preferably 120 to 270 μm, and more preferably 140 to 252 μm.

[0065] In the present invention, a blade coater with a width of 600 mm, 900 mm, 1100 mm, 1300 mm, or 1500 mm is selected for coating.

[0066] In the present invention, the non-woven fabric comprises one or more of spunlace non-woven fabric, spunbond non-woven fabric, meltblown non-woven fabric, needle-punched non-woven fabric, wet-laid non-woven fabric and heat-bonded non-woven fabric, preferably spunlace non-woven fabric.

[0067] The present invention achieves a multi-level synergistic reinforcement effect by adding a modifier (γ-aminopropyltriethoxysilane) to the matrix-filler-fiber composite system. The mechanism of action and specific effects are described as follows:

[0068] First, in terms of enhancing interfacial bonding, the amino groups in the modifier react chemically with the hydroxyl-terminated PDMS in the siloxane matrix, forming stable Si-O-Si-NH- bonds. Simultaneously, the silanol groups produced upon hydrolysis can bind to the hydroxyl groups on the filler surface, thereby establishing a chemical bond bridging network between the matrix, filler, and fiber. This ternary coupling effect significantly increases the filler's peel strength from 0.1 MPa to 0.8 MPa.

[0069] Secondly, in terms of rheological properties, the addition of the modifier produces a significant lubricating effect. It effectively reduces the frictional resistance between the filler and the matrix, lowering the viscosity of the mixed system by 15-20%, an effect accurately measured using a Brookfield viscometer. This reduced viscosity brings two important benefits: first, it significantly reduces the temperature rise during high-speed dispersion, thereby preventing thermal degradation of the silicone matrix due to overheating; second, it improves processing performance, making subsequent processes such as coating easier.

[0070] Finally, regarding storage stability, the modified filler's surface properties are altered, significantly improving its compatibility with the matrix. Experimental data shows that the treated system remains uniform and stable even after seven days of standing, with no signs of delamination. In contrast, untreated samples exhibited a sedimentation rate exceeding 30% under the same conditions. This enhanced stability not only extends the product's shelf life but also ensures consistent performance.

[0071] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0072] In the present invention, the raw materials were purchased from manufacturers as shown in Table 1.

[0073] Table 1 Raw materials

[0074]

[0075]

[0076] Example 1

[0077] Formula composition (mass parts)

[0078] Hydroxyl terminated PDMS: 30 parts; Naphthenic oil: 7 parts;

[0079] γ-aminopropyltriethoxysilane: 1 part;

[0080] Talc: 20 parts;

[0081] Calcium carbonate: 20 parts;

[0082] Bentonite: 5 parts;

[0083] Fumed silica (specific surface area ≥ 200m 2 / g): 2 parts;

[0084] Composite fiber: 15 parts.

[0085] Preparation steps:

[0086] 1) Fiber pretreatment: 1 mm long glass fiber and 2 mm long carbon fiber were mixed in a 1:1 ratio to form composite fibers.

[0087] 2) Matrix Mixing: Mix 30 parts of hydroxyl-terminated PDMS, 7 parts of naphthenic oil, and 1 part of γ-aminopropyltriethoxysilane at low speed (20 rpm) for 5 minutes, then disperse at high speed (600 rpm / min) for 10 minutes. Then, add 20 parts of talc, 20 parts of calcium carbonate, 5 parts of bentonite, and 2 parts of silica and disperse at high speed (600 rpm / min) for 15 minutes. Finally, add 15 parts of composite fiber and stir at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0088] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0089] Example 2

[0090] Formula composition (mass parts)

[0091] Methyl terminated PDMS: 30.3 parts;

[0092] Castor oil: 10.4 parts;

[0093] Vinyltrimethoxysilane: 0.8 parts;

[0094] Bentonite: 45 parts;

[0095] Composite fiber: 10.5 parts.

[0096] Preparation steps:

[0097] 1) Fiber pretreatment: 2 mm long basalt fiber and 2 mm long ceramic fiber were mixed in a ratio of 1:1 to form composite fibers.

[0098] 2) Matrix Mixing: 30.3 parts of methyl-terminated PDMS, 10.4 parts of castor oil, and 0.8 parts of vinyltrimethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 45 parts of bentonite were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 10.5 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to produce a sealant paste.

[0099] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0100] Example 3

[0101] Formula composition (mass parts)

[0102] Hydroxyl terminated PDMS: 32.5 parts;

[0103] White oil: 12.3 parts;

[0104] γ-aminopropyltriethoxysilane: 1.2 parts;

[0105] Kaolin: 25 parts;

[0106] Titanium dioxide: 6 parts;

[0107] *Silicon dioxide: 5 parts;

[0108] Composite fiber: 18 parts;

[0109] *Precipitated silica (average particle size: 1–10 μm), free metal content ≤ 50 ppm.

[0110] Preparation steps:

[0111] 1) Fiber pretreatment: 2 mm long basalt fiber and 2 mm long ceramic fiber were mixed in a ratio of 6:4 to form a composite fiber.

[0112] 2) Matrix Mixing: 32.5 parts of hydroxyl-terminated PDMS, 12.3 parts of white oil, and 1.2 parts of γ-aminopropyltriethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 25 parts of kaolin, 6 parts of titanium dioxide, and 5 parts of silicon dioxide were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 18 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0113] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0114] Example 4

[0115] Formula composition (mass parts)

[0116] Methyl terminated PDMS: 10 parts;

[0117] Rapeseed oil: 37 parts;

[0118] Vinyltrimethoxysilane: 0.5 parts;

[0119] Calcium carbonate: 27 parts;

[0120] Talc: 12.5 parts;

[0121] *Silicon dioxide: 3 parts;

[0122] Composite fiber: 10 parts;

[0123] * Fumed silica (specific surface area ≥ 150m 2 / g)

[0124] Preparation steps:

[0125] 1) Fiber pretreatment: 2 mm long bamboo fiber and 1 mm long flax fiber were mixed in a ratio of 6:4 to form composite fibers.

[0126] 2) Matrix Mixing: 10 parts methyl-terminated PDMS, 37 parts rapeseed oil, and 0.5 parts vinyltrimethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, then dispersed at high speed (600 rpm / min) for 10 minutes. Subsequently, 27 parts calcium carbonate, 12.5 parts talc, and 3 parts silicon dioxide were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 10 parts composite fiber was added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0127] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0128] Example 5

[0129] Formula composition (mass parts)

[0130] Methyl terminated PDMS: 33 parts;

[0131] Liquid paraffin oil: 11.3 parts;

[0132] Vinyltrimethoxysilane: 0.7 parts;

[0133] *Silicon dioxide: 35 parts;

[0134] Composite fiber: 20 parts;

[0135] *Precipitated silica (average particle size: 3–5 μm), free metal content ≤ 50 ppm.

[0136] Preparation steps:

[0137] 1) Fiber pretreatment: Ceramic fibers with a length of 2 mm and PI fibers with a length of 1.5 mm were mixed in a ratio of 7:3 to form composite fibers.

[0138] 2) Matrix Mixing: 33 parts of methyl-terminated PDMS, 11.3 parts of liquid paraffin oil, and 0.7 parts of vinyltrimethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 35 parts of nanosilica were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 20 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0139] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0140] Example 6

[0141] Formula composition (mass parts)

[0142] Hydroxyl terminated PDMS: 15 parts;

[0143] Methyl terminated PDMS: 15 parts;

[0144] White oil: 10 parts;

[0145] γ-aminopropyltriethoxysilane: 0.5 parts;

[0146] Vinyltrimethoxysilane: 0.5 parts;

[0147] Talc: 15 parts;

[0148] Kaolin: 14.5 parts;

[0149] Calcium carbonate: 15 parts;

[0150] *Silicon dioxide: 2.5 parts;

[0151] Composite fiber: 12 parts;

[0152] * Fumed silica (specific surface area ≥ 250m 2 / g)

[0153] Preparation steps:

[0154] 1) Fiber pretreatment: PP fibers with a length of 2 mm and PET fibers with a length of 2 mm were mixed in a ratio of 1:1 to form composite fibers.

[0155] 2) Matrix Mixing: 15 parts of hydroxyl-terminated PDMS, 15 parts of methyl-terminated PDMS, 10 parts of white oil, 0.5 parts of γ-aminopropyltriethoxysilane, and 0.5 parts of vinyltrimethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, and then dispersed at high speed (600 rpm / min) for 10 minutes. Subsequently, 15 parts of talc, 14.5 parts of kaolin, 15 parts of calcium carbonate, and 2.5 parts of silica were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 12 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0156] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0157] Example 7

[0158] Formula composition (mass parts)

[0159] Hydroxyl terminated PDMS: 22 parts;

[0160] Silicone oil: 22.5;

[0161] 1 part of γ-aminopropyltriethoxysilane;

[0162] Bentonite: 12.5 parts;

[0163] Talc: 11 parts;

[0164] Calcium carbonate: 12.5 parts;

[0165] *Silicon dioxide: 2.5 parts;

[0166] Composite fiber: 16 parts;

[0167] * Fumed silica (specific surface area ≥ 100m 2 / g)

[0168] Preparation steps:

[0169] 1) Fiber pretreatment: 2 mm long flax fiber and 2 mm long aramid fiber were mixed in a ratio of 6:4 to form composite fibers.

[0170] 2) Matrix Mixing: Mix 22 parts of hydroxyl-terminated PDMS, 22.5 parts of silicone oil, and 1 part of γ-aminopropyltriethoxysilane at low speed (20 rpm) for 5 minutes, then disperse at high speed (600 rpm) for 10 minutes. Then, add 12.5 parts of bentonite, 11 parts of talc, 12.5 parts of calcium carbonate, and 2.5 parts of silica and disperse at high speed (600 rpm) for 15 minutes. Finally, add 16 parts of composite fiber and stir at low speed (40 rpm) for 15 minutes to obtain a paste sealant.

[0171] 3) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0172] Example 8

[0173] Formula composition (mass parts)

[0174] Hydroxyl terminated PDMS: 32 parts;

[0175] Naphthenic oil: 8 parts;

[0176] γ-aminopropyltriethoxysilane: 1.2 parts;

[0177] Talc: 18 parts;

[0178] Calcium carbonate: 18 parts;

[0179] *Silicon dioxide: 3 parts;

[0180] Composite fiber: 14 parts;

[0181] * Fumed silica (surface area ≥ 200m 2 / g).

[0182] Preparation steps:

[0183] 1) Fiber pretreatment: 1 mm long glass fiber and 2 mm long carbon fiber were mixed in a 1:1 ratio to form composite fibers.

[0184] 2) Matrix Mixing: 32 parts of hydroxyl-terminated PDMS, 8 parts of naphthenic oil, and 1.2 parts of γ-aminopropyltriethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 18 parts of talc, 18 parts of calcium carbonate, and 3 parts of silica were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 14 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to produce a paste sealant.

[0185] 3) Coating molding: PET spunbond nonwoven fabric (40g / m 2), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0186] Example 9

[0187] Formula composition (mass parts)

[0188] Methyl terminated PDMS: 31 parts;

[0189] White oil: 9 parts;

[0190] Vinyltrimethoxysilane: 1 part;

[0191] Silicon dioxide: 35 parts;

[0192] Bentonite: 12 parts;

[0193] Composite fiber: 12 parts;

[0194] *Precipitated silica (particle size 3–5 μm), free metal content ≤ 50 ppm.

[0195] Preparation steps:

[0196] 1) Fiber pretreatment: PP fibers with a length of 2 mm and PET fibers with a length of 2 mm were mixed in a ratio of 1:1 to form composite fibers.

[0197] 2) Matrix Mixing: Mix 31 parts of methyl-terminated PDMS, 9 parts of white oil, and 1 part of vinyltrimethoxysilane at low speed (20 rpm / min) for 5 minutes, then disperse at high speed (600 rpm / min) for 10 minutes. Then, add 35 parts of silica and 12 parts of bentonite and disperse at high speed (600 rpm / min) for 15 minutes. Finally, add 12 parts of composite fiber and stir at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0198] 3) Coating molding: PP spunbond non-woven fabric (40g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0199] Example 10

[0200] Formula composition (mass parts)

[0201] Methyl terminated PDMS: 29 parts;

[0202] Naphthenic oil: 10 parts;

[0203] Vinyltrimethoxysilane: 1 part;

[0204] Talc: 12.5 parts;

[0205] Calcium carbonate: 10 parts;

[0206] Kaolin: 9 parts;

[0207] Bentonite: 10 parts;

[0208] *Silicon dioxide: 3.5 parts;

[0209] Composite fiber: 15 parts;

[0210] * Fumed silica (specific surface area ≥ 200m 2 / g)

[0211] Preparation steps:

[0212] 1) Fiber pretreatment: PE fibers with a length of 2 mm and PET fibers with a length of 2 mm were mixed in a ratio of 1:1 to form composite fibers.

[0213] 2) Matrix Mixing: 29 parts of methyl-terminated PDMS, 10 parts of naphthenic oil, and 1 part of vinyltrimethoxysilane were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 12.5 parts of talc, 10 parts of calcium carbonate, 9 parts of kaolin, 10 parts of bentonite, and 3.5 parts of silica were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 15 parts of composite fiber were added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0214] 3) Coating molding: PP spunbond non-woven fabric (40g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0215] Example 11

[0216] Formula composition (mass parts)

[0217] Hydroxyl terminated PDMS: 32 parts;

[0218] Naphthenic oil: 10 parts;

[0219] γ-aminopropyltriethoxysilane: 1 part;

[0220] Talc: 20 parts;

[0221] Calcium carbonate: 15 parts;

[0222] Bentonite: 5 parts;

[0223] *Silicon dioxide: 2 parts;

[0224] Glass fiber (2mm): 15 parts;

[0225] * Fumed silica (specific surface area ≥ 200m 2 / g)

[0226] Preparation steps:

[0227] 1) 32 parts of hydroxyl-terminated PDMS, 10 parts of naphthenic oil, and 1 part of γ-aminopropyltriethoxysilane were mixed with low-speed stirring (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 20 parts of talc, 15 parts of calcium carbonate, 5 parts of bentonite, and 2 parts of silicon dioxide were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 15 parts of glass fiber was added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0228] 2) Coating molding: PP spunbond non-woven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0229] Example 12

[0230] Formula composition (mass parts)

[0231] Methyl terminated PDMS: 32 parts;

[0232] Castor oil: 10 parts;

[0233] Vinyltrimethoxysilane: 0.8 parts;

[0234] Talc: 18 parts;

[0235] Calcium carbonate: 18 parts;

[0236] Bentonite: 5 parts;

[0237] *Silicon dioxide: 3 parts;

[0238] Carbon fiber (length 2mm): 13.2 parts;

[0239] * Fumed silica (surface area ≥ 200m 2 / g).

[0240] Preparation steps:

[0241] 1) 32 parts of methyl-terminated PDMS, 10 parts of naphthenic oil, and 0.8 parts of vinyltrimethoxysilane were mixed with low-speed stirring (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 18 parts of talc, 18 parts of calcium carbonate, 5 parts of bentonite, and 3 parts of silicon dioxide were added and dispersed at high speed (600 rpm / min) for 15 minutes. Finally, 13.2 parts of carbon fiber was added and stirred at low speed (40 rpm / min) for 15 minutes to obtain a paste sealant.

[0242] 2) Coating molding: PET spunbond nonwoven fabric (50g / m2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0243] Comparative Example

[0244] Formula composition (mass parts)

[0245] Hydroxyl terminated PDMS: 33 parts;

[0246] White oil: 11 parts;

[0247] Talc: 23 parts;

[0248] Calcium carbonate: 23 parts;

[0249] Bentonite: 6 parts;

[0250] *Silicon dioxide: 4 parts;

[0251] *No fiber added

[0252] * Fumed silica (surface area ≥ 200m 2 / g).

[0253] Preparation steps:

[0254] 1) 33 parts of hydroxyl-terminated PDMS and 11 parts of white oil were mixed at low speed (20 rpm / min) for 5 minutes, followed by high-speed dispersion (600 rpm / min) for 10 minutes. Subsequently, 23 parts of talc, 23 parts of calcium carbonate, 6 parts of bentonite, and 4 parts of silicon dioxide were added and dispersed at high speed (600 rpm / min) for 15 minutes to obtain a sealant paste.

[0255] 2) Coating molding: PET spunbond nonwoven fabric (50g / m 2 ), blade coating thickness 200±10μm, slitting into 15mm wide coils.

[0256] Table 2 Experimental data comparison table

[0257]

[0258]

[0259] Table 3 Comparison of experimental data of various embodiments

[0260]

[0261]

[0262] The following conclusions can be drawn from the above table:

[0263] 1. Synergistic reinforcement effect; composite fibers (such as glass fiber + carbon fiber, basalt fiber + ceramic fiber) achieve complementary rigidity and toughness through binary mixing (30:70 to 50:50 ratio), significantly improving tensile strength (peel strength up to 0.8MPa) and bite resistance (bite rate <2%).

[0264] The synergistic effect of different fibers optimizes stress distribution, reduces uneven stress between layers, and allows coarse threads to be wound in only 3-4 layers (traditionally 5-7 layers are required), reducing material usage by 30-50%.

[0265] 2. Improved interfacial bonding strength: By adding a modifier (such as γ-aminopropyltriethoxysilane), the fiber, filler and matrix are bridged through chemical bonds to form a stable Si-O-Si-NH network, and the peel strength is increased from 0.1MPa to 0.8MPa.

[0266] 3. Optimize processing and storage performance; the uniform dispersion of composite fibers reduces the system viscosity by 15-20% (measured by Brookfield viscometer), reducing the risk of thermal degradation during high-speed dispersion.

[0267] 4. Storage stability was significantly improved (no delamination for 7 days), while the single fiber and fiber-free systems showed slight sedimentation and >30% sedimentation rate, respectively.

[0268] 5. Wide adaptability; suitable for coarse (2.0mm) and super coarse threads (3.0mm), with a leakage rate of <1%, which is much lower than that of single fiber (3%) and fiber-free (8%) systems.

[0269] 6. Mechanical performance limitations: Single fibers (such as glass fiber or carbon fiber alone) lack multi-scale reinforcement effects and have poor bite resistance (3% bite rate), significantly higher than composite fibers (<1%). Peel strength is only 0.2 MPa, lower than the composite fiber system (0.8 MPa).

[0270] 7. The number of winding layers and cost disadvantages: Coarse threads require 4-5 layers of winding, and the material consumption is 20-30% more than that of composite fibers, failing to achieve the cost optimization goal.

[0271] 8. Dispersion and stability issues: Single fibers tend to agglomerate, resulting in uneven dispersion of the filler. Slight sedimentation (<10%) occurs after 7 days of storage, affecting product consistency.

[0272] 9. Insufficient mechanical strength: The peel strength of the fiber-free system is only 0.1 MPa, and the anti-bite performance is extremely poor (bite-off rate 8%), which cannot meet the high stress requirements of coarse threads.

[0273] 10. Serious material waste: Coarse threads require 5-7 layers of winding, and the material consumption is 60-100% more than that of composite fibers, which violates the invention's purpose of cost optimization (reduction of 30-50%).

[0274] 11. Poor performance stability; the sedimentation rate after 7 days of storage is >30%, which is significantly higher than that of composite fiber (no stratification) and single fiber (<10% sedimentation), resulting in unstable product performance.

[0275] 12. High leakage risk; the leakage rate is as high as 8%, far exceeding that of composite fibers (<1%) and single fibers (3%), and cannot meet the leakage prevention requirements in the fields of petroleum, chemical industry, etc.

[0276] Table 4 Performance comparison of examples

[0277]

[0278] As can be seen from the above examples, the present invention provides a non-woven fabric-based composite sealing membrane tape with a low winding number and suitable for coarse threads, and its preparation method. Through composite fiber reinforcement, modifier interface optimization, and precise coating technology, the present invention achieves a low-winding number of layers (3 layers) for coarse threads, high bite resistance (≤3%), and significant cost savings (40%). Example 1 (high-strength and pressure-resistant) exhibits the best overall performance, suitable for high-pressure and demanding operating conditions, and its technical indicators comprehensively surpass those of the comparative example.

[0279] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A non-woven fabric-based composite sealing film tape with a low number of winding layers and suitable for coarse thread, characterized in that: Prepared from the following raw materials in parts by weight: The modifier comprises γ-aminopropyltriethoxysilane and / or vinyltrimethoxysilane.

2. The non-woven fabric-based composite sealing film tape with a low number of winding layers and suitable for coarse thread according to claim 1 is characterized in that: The composite fibers include inorganic fibers and / or organic fibers; The inorganic fibers include one or more of glass fibers, carbon fibers, basalt fibers, and ceramic fibers; the organic fibers include one or more of aramid fibers, polyphenylene sulfide fibers, polypropylene fibers, polyester fibers, polyethylene fibers, polyimide fibers, flax fibers, and bamboo fibers.

3. The non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread according to claim 1 or 2, characterized in that: The matrix is ​​silicone oil, which contains one or more of liquid polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane and methyl-terminated polydimethylsiloxane.

4. The non-woven fabric-based composite sealing film tape with a low number of winding layers and adapted to coarse threads according to claim 3 is characterized in that: The plasticizer comprises one or more of castor oil, avocado oil, rapeseed oil, peanut oil, paraffin oil, liquid paraffin oil, naphthenic oil and white oil.

5. The non-woven fabric-based composite sealing film tape with a low number of winding layers and suitable for coarse thread according to claim 1, characterized in that: The filler comprises one or more of silicon dioxide, calcium carbonate, talc, kaolin and bentonite.

6. The method for preparing the non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) mixing a base, a plasticizer, and a modifier to obtain a first mixture; 2) adding the filler to the first mixture and mixing, and then adding the composite fiber and continuing to mix to obtain a wet paste sealant; 3) Apply the wet paste sealant to the non-woven fabric and cut it into wide rolls.

7. The method for preparing the non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread according to claim 6, characterized in that: In the step 1), the mixing is first low-speed mixing and then high-speed mixing, the low-speed mixing speed is 20-50 rpm and the time is 2-8 minutes; the high-speed mixing speed is 500-700 rpm and the time is 5-15 minutes.

8. The method for preparing the non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread according to claim 6 or 7, characterized in that: In the step 2), after adding the filler, the mixing speed is 500-700 rpm, and the mixing time is 10-20 minutes; after adding the composite fiber, the mixing speed is 30-50 rpm, and the mixing time is 10-20 minutes.

9. The method for preparing a non-woven fabric-based composite sealing membrane tape with a low number of winding layers and adapted to coarse thread according to claim 8, characterized in that: The coating amount is 20 to 200 g / m 2 The coating thickness is 80 to 350 μm.

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