Flame-retardant anti-corrosion viscoelastic body as well as preparation method and application thereof

Abstract

The invention provides a flame-retardant anticorrosive viscoelastic body as well as a preparation method and application thereof. The anticorrosive viscoelastic body comprises the following components in percentage by mass: 45-55% of flame-retardant polyisobutene, 30-40% of organic modified montmorillonite, 5-15% of vaseline, 3-7% of a compound flame retardant, 1-3% of a reinforcing agent, 0.5-1.0% of an antioxidant and 0-1.0% of a pigment, the flame-retardant polyisobutene is obtained by reacting a mixture of maleic anhydride grafted low-molecular-weight polyisobutene and medium-molecular-weight polyisobutene with a diethyl phosphate flame retardant, wherein the grafting rate of maleic anhydride is 1.5%-2.5%; the organic modified montmorillonite is obtained by mixing and modifying an organic cationic modifier and montmorillonite. According to the technical scheme, synergistic improvement of flame retardance, bonding strength and stability is achieved, and a safe and reliable novel protection scheme is provided for gas engineering.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion materials, and in particular to a flame-retardant anti-corrosion viscoelastic body and a preparation method and application thereof. Background Art

[0002] Before the gas wall-penetrating pipe is passed through the wall, the wall is first drilled, and then the anti-corrosion and protective treatment is carried out at the part where the gas pipe passes through the wall. The current implementation methods are mainly as follows:

[0003] (1) Wrap with polyethylene cold wrap or polyethylene heat shrink tubing. However, polyethylene cold wrap has poor adhesion, especially in low temperature environments. If the adhesive is not well adhered to the gas pipe for a long time, it will cause the tape to fall off. In addition, polyethylene heat shrink tubing requires hot heating to shrink. The construction quality is greatly affected by the quality of the anti-corrosion tape and the construction skills level, and the flame retardant effect is not good.

[0004] (2) Use an inner and outer casing, with the inner layer protecting the gas pipe and the outer layer fitting against the wall, forming a buffer layer between the inner and outer layers. Annular baffles are provided at both ends of the casing to prevent the intrusion of corrosive media. This type of casing has a complex structure, cumbersome on-site installation procedures, high construction requirements, and is prone to corrosion failure during subsequent use.

[0005] (3) Anti-corrosion fiberglass galvanized steel pipes are used at the location of gas wall-penetrating pipes. This type of pipe has excellent anti-corrosion performance, high mechanical strength, and simple construction. It only needs to be fastened with screws at both ends. However, this form requires prefabricated anti-corrosion in the factory and cannot be processed on site for secondary processing, and has poor on-site adaptability.

[0006] In response to the shortcomings of the existing technology, the inventors have tried to use an anti-corrosion pipe cover, which is placed on the wall-penetrating portion of the gas pipe. Sealing rings are used at both ends of the anti-corrosion pipe cover, and viscoelastic glue is used inside to isolate water vapor and prevent corrosion. However, it is difficult to balance the flame retardancy and adhesion of existing viscoelastic materials. Specifically, the flame retardancy of conventional viscoelastic glue is insufficient, and the addition of flame-retardant fillers will significantly reduce the bonding strength with the gas pipe (such as PE, steel pipe) and the inner wall of the pipe cover. Moreover, conventional viscoelastic glue is prone to slippage or composition analysis due to temperature fluctuations (-30°C to 60°C) during long-term service, resulting in thinning of the anti-corrosion layer or even voids, thereby losing the sealing effect.

[0007] In summary, it can be seen that the existing technology cannot simultaneously meet the multiple requirements of gas wall-penetrating pipes for flame retardancy and safety, long-term corrosion resistance, on-site adaptability and construction convenience. Summary of the Invention

[0008] In response to the above technical problems, the present invention discloses a flame-retardant and anti-corrosion viscoelastic body, a preparation method and application thereof. By specially designing the formula of the viscoelastic body, the flame retardancy, bonding strength and stability are synergistically improved, providing a safe and reliable new protection solution for gas engineering.

[0009] To this end, the technical solution adopted in the present invention is:

[0010] A flame-retardant and anti-corrosion viscoelastic body, comprising the following components by mass percentage: 45% to 55% flame-retardant polyisobutylene, 30% to 40% organic modified montmorillonite, 5% to 15% vaseline, 3% to 7% compound flame retardant, 1% to 3% reinforcing agent, 0.5% to 1.0% antioxidant, and 0% to 1.0% pigment;

[0011] The flame retardant polyisobutylene is obtained by reacting a mixture of low molecular weight polyisobutylene and medium molecular weight polyisobutylene grafted with maleic anhydride with a diethyl phosphate flame retardant, wherein the molecular weight of the low molecular weight polyisobutylene is 1000-5000 g / mol, the molecular weight of the medium molecular weight polyisobutylene is 50000-100000 g / mol, the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 1:0.9-1.1, and the maleic anhydride grafting rate is 1.5% to 2.5%;

[0012] The organic modified montmorillonite is obtained by mixing an organic cationic modifier with montmorillonite to insert the organic cations into the interlayers of the montmorillonite for modification.

[0013] The composite flame retardant is prepared by mixing microencapsulated red phosphorus and aluminum hydroxide in a mass ratio of 1:09-1.1. The microencapsulated red phosphorus and montmorillonite have a synergistic flame retardant effect, and the aluminum hydroxide absorbs heat and decomposes to release water vapor.

[0014] Among them, diethyl phosphate is also diethyl phosphate, chemical formula: C4H 11 O4P, Cas: 598-02-7. Organically modified montmorillonite (OMMT) is a typical layered silicate mineral and a 2:1 clay mineral (i.e., each structural unit consists of two layers of silicon-oxygen tetrahedrons sandwiched between one layer of aluminum-oxygen octahedrons). Its layered structure is key to flame retardancy and enhanced polymer performance. Organic cations (such as quaternary ammonium salts) are inserted between the layers through ion exchange to improve compatibility with polymers. After modification, the interlayer spacing is expanded to 2–3 nm, and the surface hydrophobicity is enhanced, making it suitable for non-polar polymers such as PIB. The compound flame retardant is made by mixing microencapsulated red phosphorus and aluminum hydroxide. The red phosphorus can generate phosphoric acid-coated nanosheets, which enhance the barrier properties of the carbon layer. Aluminum hydroxide decomposes upon endothermic absorption, releasing water vapor.

[0015] This technical solution adopts the grafting modification of low molecular weight polyisobutylene and medium molecular weight polyisobutylene materials, and reacts them with diethyl phosphate flame retardant to obtain flame retardant polyisobutylene, which is then used as the main raw material of flame retardant viscoelastic material. By adding organic modified montmorillonite, vaseline, compound flame retardant, reinforcing agent, antioxidant, etc., the obtained material has good flame retardant effect and can reach V0 level. More importantly, it has good bonding strength with polar and non-polar materials, isolates water vapor and has permanent curing properties, and does not precipitate or slip, with good long-term stability. It can provide excellent corrosion resistance and long-term flame retardancy for gas pipes, and has good bonding to plastic pipe covers and gas pipes, without quality abnormalities such as falling off and precipitation, and can maintain the long-term stability of gas pipelines in harsh corrosive environments.

[0016] As a further improvement of the present invention, the flame retardant polyisobutylene is prepared by the following steps:

[0017] Step S1, vacuum drying the low molecular weight polyisobutylene and the medium molecular weight polyisobutylene to obtain dried PIB;

[0018] Step S2, dissolving the dried PIB in a solvent, introducing a protective gas, adding maleic anhydride and a crosslinking agent, stirring and dissolving, and reacting at 90-110° C. under a protective gas atmosphere for 3-5 hours; cooling to room temperature, adding a polymerization inhibitor to adjust the maleic anhydride grafting rate to 1.5%-2.5%, and obtaining a mixture of low molecular weight polyisobutylene and medium molecular weight polyisobutylene grafted with maleic anhydride; wherein the amount of maleic anhydride added is 5%-8% of the mass of the dried PIB;

[0019] Step S3, adding diethyl phosphate flame retardant to the mixture of the low molecular weight polyisobutylene and the medium molecular weight polyisobutylene grafted with maleic anhydride, reacting at 80-100°C for 2-4 hours under a protective gas atmosphere, pouring the reaction solution into cold methanol at 0-5°C, stirring to precipitate the product, vacuum filtering, washing with methanol, and vacuum drying to obtain flame-retardant polyisobutylene; wherein the amount of the diethyl phosphate flame retardant added is 0.9-1.1 times the amount of maleic anhydride.

[0020] As a further improvement of the present invention, the solvent is toluene.

[0021] As a further improvement of the present invention, the crosslinking agent is DCP. Furthermore, the amount of DCP added is 1% to 3% by weight of the mixture of the maleic anhydride-grafted low molecular weight polyisobutylene and the medium molecular weight polyisobutylene, and further, is 2% by weight of the mixture of the maleic anhydride-grafted low molecular weight polyisobutylene and the medium molecular weight polyisobutylene.

[0022] As a further improvement of the present invention, the protective gas is nitrogen or an inert gas.

[0023] As a further improvement of the present invention, the polymerization inhibitor is hydroquinone; further, the amount of the polymerization inhibitor added is 0.1 wt % of the reaction system.

[0024] As a further improvement of the present invention, in step S3, the amount of DEP added is 1 times the amount of maleic anhydride.

[0025] As a further improvement of the present invention, the organic cationic modifier is at least one of cetyltrimethylammonium bromide (CTAB) and bis(hydroxyethyl)methyltallow ammonium. The organic modified montmorillonite can be a commercially available product.

[0026] As a further improvement of the present invention, the organic modified montmorillonite is montmorillonite modified with cetyltrimethylammonium bromide (CTAB) (CTAB-MMT).

[0027] As a further improvement of the present invention, the reinforcing agent is fumed silica. Furthermore, the fumed silica is spherical with a particle size of 1 to 100 nanometers. Fumed silica exhibits a flocculent and reticular quasi-granular structure. After the fumed silica is uniformly dispersed in the viscoelastic, a large number of particles form hydrogen bonds through surface silanol (Si-OH) groups, forming a silica aggregate network. This restricts the fluidity of the system and increases viscosity, thereby providing reinforcement and thickening.

[0028] As a further improvement of the present invention, the melting point of the white vaseline is 45-60°C and the needle penetration is 100-130 mm. Vaseline is a semi-liquid mixture of paraffinic hydrocarbons or saturated hydrocarbons obtained by petroleum fractionation, has good wettability, and has excellent rust-proof and waterproof effects.

[0029] As a further improvement of the present invention, the pigment is phthalocyanine green.

[0030] As a further improvement of the present invention, the antioxidant is at least one of antioxidant 1010, antioxidant 1076 or antioxidant SKY-1035.

[0031] As a further improvement of the present invention, the molecular weight of the low molecular weight polyisobutylene is 1900-2500 g / mol; the molecular weight of the medium molecular weight polyisobutylene is 80,000-90,000 g / mol.

[0032] As a further improvement of the present invention, the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 1:1.

[0033] As a further improvement of the present invention, the mass ratio of the microencapsulated red phosphorus to aluminum hydroxide is 1:1.

[0034] The present invention discloses a method for preparing the flame retardant and anti-corrosion viscoelastic body, comprising the following steps:

[0035] Step S10, adding the raw materials of each component into a kneader, and kneading at 140±15° C. for 1 to 1.5 hours to prepare a cement;

[0036] Step S20: transporting the mastic to a reactor through a single-screw extruder for secondary mixing at a mixing temperature of 130±10° C. for 0.5 to 1 hour to obtain a flame-retardant and anti-corrosion viscoelastic raw material.

[0037] As a further improvement of the present invention, the method for preparing the flame retardant and anti-corrosion viscoelastic body further comprises:

[0038] In step S30, the flame-retardant, anti-corrosion viscoelastic material mixed in the reactor is pumped to a coating machine via a gear pump. It is then extruded through a flat slit die onto a polyethylene release film. Simultaneously, a PET release film is applied to the other side of the viscoelastic adhesive layer. After lamination, the material is pressed to a desired thickness using a double roller, and then cooled by a cooling roller. This technical solution allows the flame-retardant, anti-corrosion viscoelastic material to be prefabricated into a sheet shape, making it easier to apply and process.

[0039] The present invention discloses the application of the flame-retardant and anti-corrosion viscoelastic body as described above. The flame-retardant and anti-corrosion viscoelastic body is used in a flame-retardant anti-corrosion pipe cover for a gas pipe passing through a wall.

[0040] The present invention discloses a flame-retardant, anti-corrosion pipe cover for gas pipes penetrating walls. The cover comprises a pipe cover housing, within which a flame-retardant, anti-corrosion fixing layer is disposed. The pipe cover housing is made of flame-retardant engineering plastic, and the flame-retardant, anti-corrosion fixing layer is made of the flame-retardant, anti-corrosion viscoelastic material described above. Furthermore, sealing rings are provided on the inner sides of both ends of the pipe cover housing.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] First, the technical solution of the present invention achieves a breakthrough in the formulation of flame-retardant polymer viscoelastic materials. Modified flame-retardant polyisobutylene is used as the main raw material, and is mixed with organically modified montmorillonite, phosphate ester and other materials in a certain ratio to achieve better flame retardancy and performance enhancement. During combustion, a "maze effect" is formed to delay the diffusion of pyrolysis gases. Moreover, due to the hydrophobic properties of the surface of the organically modified montmorillonite, it has good compatibility with the flame-retardant polyisobutylene. The resulting flame-retardant and corrosion-resistant viscoelastic has good water vapor isolation and non-solidification properties, good bonding strength with both polar and non-polar materials, and good bonding strength with gas pipes and pipe cover shells, and has better flame retardancy, better long-term durability, and is more stable.

[0043] Second, the flame-retardant anti-corrosion pipe cover for gas pipes passing through walls in the technical solution of the present invention adopts a composite structure, and the outer layer adopts flame-retardant engineering plastic as an armor layer, which has excellent mechanical strength and impact toughness, can withstand external stress impact, is not easily damaged, and has a good protective effect on the internal viscoelastic anti-corrosion material; combined with the internal flame-retardant viscoelastic anti-corrosion material, the middle flame-retardant viscoelastic fits tightly with the gas pipe, providing long-term anti-corrosion protection; the rubber sealing rings at both ends seal the two ends of the pipe cover, and at the same time, increase the friction between the pipe and the gas pipe to prevent the pipe cover from displacement; the engineering plastic shell outside the viscoelastic body has many advantages such as high mechanical strength, light weight, good toughness, and flame retardancy, which protects the internal viscoelastic material. A two-flap, edge-clip connection can be used on site, which is easy to operate and only needs to be cut according to the size and length of the site. On-site installation only requires alignment and tightening to complete the anti-corrosion protection of the wall pipe, reducing the impact of the construction environment, skill level, etc. on the site. There is no need to use fire, it is easy to operate, environmentally friendly and flame retardant, and has excellent anti-corrosion and protection effects on gas pipes, extending the maintenance and service life of gas wall pipes. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention are described in further detail below.

[0045] Example 1

[0046] Flame-retardant polyisobutylene a is prepared by the following method:

[0047] 2 parts by weight of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.5:0.5) was dried in a 60°C vacuum oven for 6 hours to remove moisture. The dried PIB was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.1 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0048] Temperature: 90–110°C (oil bath temperature control), time: 3–5 hours (continuous nitrogen protection). Subsequently, rapidly cool to room temperature and add a small amount of hydroquinone (0.1 wt% of the reaction system) to suppress free radicals and control the maleic anhydride (MAH) grafting rate to 1.5% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), time: 2–3 hours, protective gas: continuous nitrogen.

[0049] The reaction mixture was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. The product was vacuum filtered and washed three times with methanol to remove unreacted MAH, DEP, and homopolymer. Drying: Dry in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene a.

[0050] Example 2

[0051] The flame retardant polyisobutylene b is prepared by the following method:

[0052] 2 parts by weight of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.5:0.5) was dried in a vacuum oven at 60°C for 6 hours to remove moisture. The dried PIB was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.16 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0053] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 2.5% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketing with nitrogen.

[0054] The reaction mixture was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. The product was vacuum filtered and washed three times with methanol to remove unreacted MAH, DEP, and homopolymer. Drying: Dry in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene b.

[0055] Example 3

[0056] Preparation of flame retardant polyisobutylene C, prepared by the following method:

[0057] 2 parts by weight of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.5:0.5) was dried in a vacuum oven at 60°C for 6 hours to remove moisture. The dried PIB was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.14 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0058] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 2.0% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketing with nitrogen.

[0059] The reaction solution was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. Vacuum filtration was performed and washed with methanol three times to remove unreacted MAH, DEP and homopolymer. Drying: Dry in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene c

[0060] Comparative Example 1

[0061] The flame retardant polyisobutylene d was prepared by the following method:

[0062] 2 parts by weight of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.5:0.5) was dried in a 60°C vacuum oven for 6 hours to remove moisture. The dried PIB was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.1 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0063] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 1% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketed with nitrogen.

[0064] The reaction solution was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. Vacuum filtration was performed and washed with methanol three times to remove unreacted MAH, DEP and homopolymer. Drying: Drying in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene d

[0065] Comparative Example 2

[0066] The flame retardant polyisobutylene e was prepared by the following method:

[0067] 2 parts by weight of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.5:0.5) was dried in a 60°C vacuum oven for 6 hours to remove moisture. The dried PIB was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.2 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0068] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 3% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketing with nitrogen.

[0069] The reaction solution was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. Vacuum filtration was performed and washed with methanol three times to remove unreacted MAH, DEP and homopolymer. Drying: Dry in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene e

[0070] Comparative Example 3

[0071] The flame retardant polyisobutylene f is prepared by the following method:

[0072] Modified polyisobutylene was prepared by the following method: 2 parts of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.3:0.7) were dried in a vacuum oven at 60°C for 6 hours to remove moisture. The dried polyisobutylene bismuth acid (PIB) was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.14 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0073] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 2.0% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketing with nitrogen.

[0074] The reaction solution was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. Vacuum filtration was performed and washed with methanol three times to remove unreacted MAH, DEP and homopolymer. Drying: Drying in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene f

[0075] Comparative Example 4

[0076] Flame retardant polyisobutylene g was prepared by the following method:

[0077] Modified polyisobutylene was prepared by the following method: 2 parts of polyisobutylene (comprising low molecular weight polyisobutylene and medium molecular weight polyisobutylene in a weight ratio of 0.7:0.3) were dried in a 60°C vacuum oven for 6 hours to remove moisture. The dried polyisobutylene bismuth acid (PIB) was dissolved in 6 parts of toluene (10–20 wt%) and stirred until completely dissolved. Nitrogen was then passed through the reaction flask for 30 minutes to displace the oxygen. 0.14 parts of MAH and 0.04 parts of DCP were added and stirred to dissolve.

[0078] Temperature: 90–110°C (oil bath temperature control), reaction time: 3–5 hours (continuous nitrogen blanket). Subsequently, rapidly cool to room temperature, and add a small amount of hydroquinone (0.1 wt%) to suppress free radicals. The maleic anhydride (MAH) grafting rate is controlled to 2.0% during the reaction. DEP is added at a 1:1 molar ratio of MAH to DEP. Reaction conditions: temperature: 80–100°C (toluene solvent), reaction time: 2–3 hours, blanketing with nitrogen.

[0079] The reaction solution was slowly poured into cold methanol (0–5°C) and stirred to precipitate the product. Vacuum filtration was performed and washed with methanol three times to remove unreacted MAH, DEP and homopolymer. Drying: Dry in a vacuum oven at 40°C for 24 hours to obtain flame-retardant polyisobutylene g

[0080] Comparative Example 5

[0081] The flame retardant polyisobutylene b1 was prepared by the following method:

[0082] Compared with flame-retardant polyisobutylene b, flame-retardant diethyl phosphate (DEP) was replaced with melamine cyanurate (MCA), and the rest were the same as those in Preparation Example 2, to obtain flame-retardant polyisobutylene b1.

[0083] The specific information of each raw material in the above embodiment is as follows:

[0084] Low molecular weight polyisobutylene, molecular weight 1900 ~ 2500g / mol; Shandong Hongrui New Material Technology Co., Ltd. HRD-23H can be used.

[0085] Medium molecular weight polyisobutylene, molecular weight 80000 ~ 90000g / mol; Shandong Hongrui New Material Technology Co., Ltd. HRD-850 can be used.

[0086] Toluene, CAS number: 108-88-3;

[0087] Maleic anhydride, CAS number: 108-31-6;

[0088] Hydroquinone, CAS number: 123-31-9;

[0089] Diethyl phosphate, CAS number: 598-02-7;

[0090] Methanol, CAS number: 67-56-1;

[0091] Melamine cyanurate, CAS number: 37640-57-6;

[0092] The nitrogen is pure nitrogen (99.99%), the oxygen is industrial pure oxygen (99.5%), and other raw materials or reagents, unless otherwise specified, can be purchased from commercial sources.

[0093] Example 11

[0094] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 45% flame-retardant polyisobutylene a; 40% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 7% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0095] The preparation steps are:

[0096] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0097] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0098] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0099] Example 12

[0100] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 55% flame-retardant polyisobutylene a; 30% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 5% industrial petrolatum; 6% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0101] The preparation steps are:

[0102] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0103] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0104] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0105] Example 13

[0106] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 47% flame-retardant polyisobutylene C; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 10% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0107] The preparation steps are:

[0108] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0109] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0110] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0111] Example 14

[0112] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 45% flame-retardant polyisobutylene b; 40% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 7% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0113] The preparation steps are:

[0114] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0115] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0116] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0117] Example 15

[0118] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 55% flame-retardant polyisobutylene b; 30% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 5% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0119] The preparation steps are:

[0120] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0121] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0122] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0123] Example 16

[0124] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 50% flame-retardant polyisobutylene C; 30% dihydroxyethyl methyl tallow ammonium (DODMAC)-modified montmorillonite (DODMAC-MMT); 5% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. The DODMAC-MMT was commercially available.

[0125] The preparation steps are:

[0126] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0127] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0128] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0129] Comparative Example 11

[0130] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 50% flame-retardant polyisobutylene d; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 7% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0131] The preparation steps are:

[0132] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0133] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0134] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0135] Comparative Example 12

[0136] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 50% flame-retardant polyisobutylene e; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 7% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0137] The preparation steps are:

[0138] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0139] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0140] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0141] Comparative Example 13

[0142] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 47% flame-retardant polyisobutylene f; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 10% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0143] The preparation steps are:

[0144] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0145] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0146] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0147] Comparative Example 14

[0148] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 47% flame-retardant polyisobutylene g; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 10% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0149] The preparation steps are:

[0150] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0151] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0152] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0153] Comparative Example 15

[0154] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 147% flame-retardant polyisobutylene b; 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 10% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0155] The preparation steps are:

[0156] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0157] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0158] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0159] Comparative Example 16

[0160] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 43% flame-retardant polyisobutylene C; 40% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 8% industrial petrolatum; 5% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0161] The preparation steps are:

[0162] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0163] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0164] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0165] Comparative Example 17

[0166] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 57% flame-retardant polyisobutylene C; 30% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 5% industrial petrolatum; 4% compounded flame retardant; 4% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0167] The preparation steps are:

[0168] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0169] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0170] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0171] Comparative Example 18

[0172] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 45% flame-retardant polyisobutylene C; 42% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 6% industrial petrolatum; 3% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0173] The preparation steps are:

[0174] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0175] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0176] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0177] Comparative Example 19

[0178] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 55% flame-retardant polyisobutylene C; 28% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 8% industrial petrolatum; 5% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0179] The preparation steps are:

[0180] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0181] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0182] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0183] Comparative Example 20

[0184] A flame-retardant viscoelastic adhesive was prepared using the following formula (% by mass): 47% unmodified polyisobutylene (low molecular weight: medium molecular weight polyisobutylene = 0.5:0.5); 35% cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CTAB-MMT); 10% industrial petrolatum; 4% compounded flame retardant; 2% fumed silica; 1% antioxidant; and 1% colorant. CTAB-MMT was commercially available.

[0185] The preparation steps are:

[0186] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0187] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0188] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0189] Comparative Example 21

[0190] A flame-retardant viscoelastic adhesive was prepared with the following formula (% is by mass): flame-retardant polyisobutylene C 47%; unmodified montmorillonite 35%; industrial vaseline 10%; compound flame retardant 4%; fumed silica 2%; antioxidant 1%; and color powder 1%.

[0191] The preparation steps are:

[0192] 1. Add the raw materials for preparing the viscoelastic glue into a kneader and knead at 140±15°C for 1 to 1.5 hours to form a cement paste;

[0193] 2. The viscoelastic glue is conveyed to a reactor through a single-screw extruder for secondary mixing at a temperature of 130±10°C for 0.5 to 1 hour;

[0194] 3. The viscoelastic glue mixed in the reactor is transported to the glue coater through a gear pump, extruded through a flat slit die and coated on the polyethylene release film. At the same time, the PET release film is attached to the other side of the viscoelastic glue layer. After attachment, it is pressed to the set thickness by double rollers and then cooled by cooling rollers.

[0195] The formulations of Examples 11 to 16 are shown in Table 1, and the performance test results are shown in Table 2.

[0196] Table 1 Formulations of Examples 11 to 16

[0197]

[0198] Table 2 Performance test results of Examples 11 to 16

[0199]

[0200] The peel strength test requires a coverage of ≥95%. This coverage refers to the following: The viscoelastic material is circumferentially cut into a strip approximately 20 mm wide and 100 mm long. The cut should penetrate the adhesive layer to the interface to be measured. One end of the strip is pried up approximately 20 mm. The anti-corrosion layer at the raised end is fixed to the dynamometer's hook using a fixture. Within the peeled area, the adhesive layer covering the substrate accounts for 95% of the peeled area.

[0201] Anti-slip testing: A DN15 anti-corrosion pipe cover, 200mm long, was installed on a DN15 gas pipe held at a 90-degree angle. After 100 days in a 60°C environment, the cover was observed for slippage. The anti-slip test involved fixing the cover to be tested with a flame-retardant viscoelastic adhesive to the inner wall of the cover shell. The cover was then installed on the gas pipe surface without sealing rings at either end.

[0202] Precipitation testing: Select a DN15 anti-corrosion pipe cover, 200mm long, and install it on the surface of a horizontally suspended DN15 gas pipe. Place it outdoors in an open environment and expose it to sunlight. After 100 days, observe the ends of the pipe cover and the joints for viscoelastic adhesive precipitation. The anti-corrosion pipe cover used in the precipitation test is fixed with the flame-retardant viscoelastic adhesive to the inner wall of the pipe cover shell. The pipe cover is then installed on the gas pipe surface and sealed with sealing rings at both ends for testing.

[0203] The test methods for high-temperature drop sag (110°C, 48h), peel strength, chemical immersion resistance (room temperature, 90d), lap shear strength, peel strength after dry heat aging (115°C, 100d), and water absorption refer to ISO21809-3:2016. The flame retardancy test refers to UL94.

[0204] The formulations of Comparative Examples 11 to 16 are shown in Table 3, and the performance test results are shown in Table 4.

[0205] Table 3 Formulas of Comparative Examples 11 to 16

[0206]

[0207]

[0208] Table 4 Performance test results of Comparative Examples 11 to 16

[0209]

[0210] The detection methods in the above table are the same as those in Table 2, and the same is true for Table 6 below.

[0211] The formulations of Comparative Examples 17 to 21 are shown in Table 5, and the performance test results are shown in Table 6.

[0212] Table 5 Formulas of Comparative Examples 17 to 21

[0213]

[0214] Table 6 Performance test results of Comparative Examples 17 to 21

[0215]

[0216] From the comparison of Tables 1 to 6 above, it can be seen that the technical solution of the embodiment of the present invention has low water absorption rate of the viscoelastic glue, excellent anti-corrosion performance, and flame retardant effect reaching V0 level. It has good bonding strength with the gas pipe and the pipe cover shell, and there is no slippage or precipitation after long-term aging, and the long-term durability is better and more stable.

[0217] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A flame retardant and anti-corrosion viscoelastic body, characterized in that: The components and their mass percentages are as follows: flame retardant polyisobutylene 45% to 55%, organic modified montmorillonite 30% to 40%, vaseline 5% to 15%, compound flame retardant 3% to 7%, reinforcing agent 1% to 3%, antioxidant 0.5% to 1.0%, and pigment 0% to 1.0%. The flame retardant polyisobutylene is obtained by reacting a mixture of low molecular weight polyisobutylene and medium molecular weight polyisobutylene grafted with maleic anhydride with a diethyl phosphate flame retardant, wherein the molecular weight of the low molecular weight polyisobutylene is 1000-5000 g / mol, the molecular weight of the medium molecular weight polyisobutylene is 50000-100000 g / mol, the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 1:0.9-1.1, and the maleic anhydride grafting rate is 1.5% to 2.5%; The organic modified montmorillonite is obtained by mixing an organic cationic modifier with montmorillonite to insert the organic cations into the interlayers of the montmorillonite for modification. The compound flame retardant is prepared by mixing microencapsulated red phosphorus and aluminum hydroxide in a mass ratio of 1:09-1.

1.

2. The flame-retardant and anti-corrosion viscoelastic body according to claim 1, characterized in that: The flame retardant polyisobutylene is prepared by the following steps: Step S1, vacuum drying the low molecular weight polyisobutylene and the medium molecular weight polyisobutylene to obtain dried PIB; Step S2, dissolving the dried PIB in a solvent, introducing a protective gas, adding maleic anhydride and a crosslinking agent, stirring and dissolving, and reacting at 90-110° C. under a protective gas atmosphere for 3-5 hours; cooling to room temperature, adding a polymerization inhibitor to adjust the maleic anhydride grafting rate to 1.5%-2.5%, and obtaining a mixture of low molecular weight polyisobutylene and medium molecular weight polyisobutylene grafted with maleic anhydride; wherein the amount of maleic anhydride added is 5%-8% of the mass of the dried PIB; Step S3, adding diethyl phosphate flame retardant to the mixture of the low molecular weight polyisobutylene and the medium molecular weight polyisobutylene grafted with maleic anhydride, reacting at 80-100°C for 2-4 hours under a protective gas atmosphere, pouring the reaction solution into cold methanol at 0-5°C, stirring to precipitate the product, vacuum filtering, washing with methanol, and vacuum drying to obtain flame-retardant polyisobutylene; wherein the amount of the diethyl phosphate flame retardant added is 0.9-1.1 times the amount of maleic anhydride.

3. The flame-retardant and anti-corrosion viscoelastic body according to claim 2, characterized in that: The solvent is toluene, the cross-linking agent is DCP, the protective gas is nitrogen or an inert gas, and the polymerization inhibitor is hydroquinone; In step S3, the amount of DEP added is 1 times the amount of maleic anhydride.

4. The flame-retardant and anti-corrosion viscoelastic body according to claim 1, characterized in that: The organic cationic modifier is at least one of cetyltrimethylammonium bromide and bis(hydroxyethyl)methyltallow ammonium.

5. The flame retardant and anti-corrosion viscoelastic body according to claim 1, characterized in that: The reinforcing agent is fumed silica, which is spherical and has a particle size of 1 to 100 nanometers; the antioxidant is at least one of antioxidant 1010, antioxidant 1076, or antioxidant SKY-1035; The molecular weight of the low molecular weight polyisobutylene is 1900 to 2500 g / mol; the molecular weight of the medium molecular weight polyisobutylene is 80,000 to 90,000 g / mol.

6. The flame-retardant and anti-corrosion viscoelastic body according to claim 5, characterized in that: The mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 1:1; the mass ratio of the microencapsulated red phosphorus to aluminum hydroxide is 1:

1.

7. The method for preparing a flame retardant and anticorrosive viscoelastic body according to any one of claims 1 to 6, characterized in that: The steps include: Step S10, adding the raw materials of each component into a kneader, kneading at 140±15°C for 1 to 1.5 hours to make a clay; Step S20, conveying the clay to a reactor through a single-screw extruder for secondary mixing, the mixing temperature of the reactor is 130±10°C, and the mixing time is 0.5 to 1 hour to obtain a flame retardant and anti-corrosion viscoelastic raw material.

8. The method for preparing a flame retardant and anti-corrosion viscoelastic body according to claim 7, characterized in that: Also includes: In step S30, the flame-retardant and anti-corrosion viscoelastic raw material mixed in the reactor is transported to a coating machine via a gear pump, extruded through a flat slit die and coated on a polyethylene release film. At the same time, a PET release film is adhered to the other side of the viscoelastic adhesive layer. After adhesion, it is pressed to a set thickness by a double roller and then cooled by a cooling roller.

9. Use of the flame retardant and anticorrosive viscoelastic body according to any one of claims 1 to 6, characterized in that: The flame-retardant and anti-corrosion viscoelastic body is used in a flame-retardant and anti-corrosion pipe cover for a gas pipe passing through a wall.

10. A flame-retardant anti-corrosion pipe cover for a gas pipe passing through a wall, characterized by: It includes a pipe cover shell, sealing rings are provided on the inner sides of both ends of the pipe cover shell, a flame retardant and anti-corrosion fixing layer is provided inside the shell, the material of the pipe cover shell is flame retardant engineering plastic, and the material of the flame retardant and anti-corrosion fixing layer is the flame retardant and anti-corrosion viscoelastic body described in any one of claims 1 to 6.

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