Flame-retardant cold patch adhesive as well as preparation method and application thereof

Abstract

The invention discloses a flame-retardant cold patch adhesive as well as a preparation method and application thereof. The flame-retardant cold patch adhesive comprises a base material and a curing agent, the base material comprises the following preparation raw materials: first polyol, a flame retardant, a chain extender and a tackifier, and the first polyol is selected from one or two of polycaprolactone diol and polycaprolactone triol; the curing agent is a prepolymer of modified MDI and second polyol, and the second polyol is selected from one or two of polytetrahydrofuran ether polyol and hydroxyl-terminated polybutadiene. The flame-retardant cold patch adhesive is low in hygroscopicity, good in tensile strength, elongation, flame retardance and insulativity and excellent in comprehensive performance, and is particularly suitable for repairing an outer sheath or an insulating layer of a cable. The invention also provides a preparation method and application of the flame-retardant cold patch adhesive.

Description

Technical Field

[0001] The invention relates to the technical field of insulating materials, and in particular to a flame retardant cold patch adhesive and a preparation method and application thereof. Background Art

[0002] Cables are an indispensable and important equipment in modern life, and the insulation of cables is also the key to their normal operation. However, due to various reasons, the insulation layer of cables is sometimes damaged or aged, which requires the cables to be repaired. The use of cold patch glue for repair is not only simple in process, low in cost, and easy to ensure the quality of the project, but also conducive to the safe and reliable operation of the cable line. It can also be quickly formed without affecting the normal power supply of the cable. Compared with hot patch glue, cold patch glue can be operated on site, which is easy to ensure the quality of the project and does not require the cable to be recovered to the ground, thereby greatly reducing the amount of work and reducing the impact of cable replacement on production safety.

[0003] Cable cold patch glue needs to meet the requirements of flame retardancy and insulation. Considering the actual use conditions, it also needs to have low moisture absorption and certain mechanical properties, such as higher requirements for strength and toughness, specifically tensile strength ≥ 7MPa, elongation at break ≥ 300%. Existing cold patch glues are difficult to take into account the above-mentioned multiple performances. For example, they have high moisture absorption and are easy to absorb water in underwater environments, resulting in a significant decrease in insulation performance, which in turn causes failure problems; or poor mechanical properties affect long-term safety. In practical applications, in order to obtain better insulation effects, a layer of waterproof insulation tape is usually added, but this will also increase the cost of use accordingly.

[0004] Therefore, it is necessary to develop a flame-retardant cold repair adhesive with low hygroscopicity and high mechanical properties. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a flame retardant cold patch adhesive with low hygroscopicity, good tensile strength, elongation, flame retardancy and insulation, and excellent comprehensive performance.

[0006] The invention also provides a method for preparing the flame retardant cold patch adhesive.

[0007] The present invention also proposes the application of the flame retardant cold repair adhesive.

[0008] The first aspect of the present invention relates to a flame retardant cold patch adhesive, including a base material and a curing agent, wherein the base material includes the following preparation raw materials: a first polyol, a flame retardant, a chain extender, and a tackifier, wherein the first polyol is selected from one or two of polycaprolactone diol and polycaprolactone triol; the curing agent is a prepolymer of modified MDI and a second polyol, wherein the modified MDI includes carbodiimide modified MDI; the second polyol is selected from one or two of polytetramethyleneimine ether polyol and terminal hydroxyl polybutadiene.

[0009] The flame retardant cold patch adhesive according to the first embodiment of the present invention has at least the following beneficial effects:

[0010] Polycaprolactone diol and polycaprolactone triol have low hygroscopicity and good moisture and heat stability, giving the material good mechanical properties such as tensile strength and elongation.

[0011] Carbodiimide-modified MDI is formed by introducing some carbodiimide (–N=C=N–) groups into MDI prepolymer (using -NCO to partially condense into carbodiimide groups under high temperature and catalyst, and this molecular structure is liquid at room temperature), and using carbodiimide groups to improve heat aging resistance and hydrolysis resistance. In addition, the use of carbodiimide-modified MDI can obtain higher tensile strength and elongation. Under the same conditions, if only conventional isocyanate curing agents such as PAPI are used, the cold patch glue produced has high hardness and low elongation at break. Further modification with a second polyol has the following advantages: polytetrahydrofuran ether polyol has a flexible polyether chain structure, which can significantly improve the elongation of the material, and has good hydrolysis resistance and aging resistance, which is beneficial to materials exposed to humid environments for a long time; terminal hydroxyl polybutadiene provides excellent impact resistance and strength, and its low polarity and hydrophobicity help improve the insulation of the material and reduce hygroscopicity. Therefore, after modification with the second polyol, the hydrolysis resistance is further improved, and at least the flexibility of the material can be ensured, thereby increasing the service life.

[0012] The addition of flame retardants improves the flame retardant properties of cold patch adhesive. Through the combination of base material and MDI prepolymer, it can better guarantee the mechanical properties and hydrolysis resistance, and is more conducive to giving full play to the advantages of flame retardants. For example, while flame retardant, it effectively guarantees the overall performance of the material, so as not to cause excessive loss of other properties due to the addition of flame retardants.

[0013] Chain extenders can increase molecular weight and cross-link density, thereby increasing tensile strength. Tackifiers can improve adhesion properties, ensuring that the cold patch adhesive has good adhesion during use and is suitable for long-term use.

[0014] By combining the above components, a flame-retardant cold patch adhesive with low moisture absorption, high mechanical properties (tensile strength and elongation), high flame retardancy and high insulation is obtained. When used for repairing the outer sheath or insulation layer of the cable, it can ensure insulation while reducing the risk of cable failure when working underwater, and the cold patch adhesive repair reduces the cable repair cost.

[0015] According to some embodiments of the present invention, the molecular weight of the first polyol is 1500 to 4500. When the first polyol is a diol, the corresponding hydroxyl value is about 25 to 75 mgKOH / g; when it is a triol, the corresponding hydroxyl value is about 37 to 112 mgKOH / g. Specifically, the molecular weight of the first polyol can be 1500, 2000, 2500, 3000, 3500, 4000, 4500 or any value therebetween.

[0016] According to some embodiments of the present invention, the modified MDI includes MDI and carbodiimide-modified MDI.

[0017] According to some embodiments of the present invention, the mass fraction of the carbodiimide-modified MDI in the modified MDI is ≥5%.

[0018] According to some embodiments of the present invention, the mass fraction of the carbodiimide-modified MDI in the modified MDI is ≥ 10%, for example, specifically 10% to 50%, or 10% to 30%.

[0019] According to some embodiments of the present invention, the mass percentage of isocyanate in the modified MDI is 20% to 30%. The isocyanate content can be adjusted by controlling the modification degree of carbodiimide to better balance the reaction activity and material performance.

[0020] According to some embodiments of the present invention, the second polyol includes polytetramethylene ether polyol, specifically polytetramethylene ether diol.

[0021] According to some embodiments of the present invention, the hydroxyl value of the second polyol is 40 to 70 mgKOH / g.

[0022] According to some embodiments of the present invention, in the curing agent, the mass ratio of the second polyol to the modified MDI is 1:1 to 4:1. For example, it can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1 or any value therebetween.

[0023] According to some embodiments of the present invention, in the curing agent, the mass ratio of the second polyol to the modified MDI is 1:1 to 2.5:1.

[0024] Controlling the hydroxyl value and dosage of the second polyol in the curing agent and adjusting the degree of modification (expressed as different isocyanate contents in the modified MDI) are more conducive to bringing into play the performance advantages of the second polyol, while ensuring the curing rate and improving the construction performance.

[0025] According to some embodiments of the present invention, the mass of the curing agent is 100% to 500% of the mass of the first polyol, and can be 100%, 150%, 200%, 250%, 300%, 350%, 400%, 450%, 500% or any value therebetween.

[0026] According to some embodiments of the present invention, the mass of the curing agent is 200% to 450% of the mass of the first polyol.

[0027] According to some embodiments of the present invention, the flame retardant is selected from one or more of antimony trioxide, decabromodiphenylethane, 2,3-dichloropropyl phosphate, and aluminum hydroxide.

[0028] According to some embodiments of the present invention, the flame retardant is selected from at least two of antimony trioxide, decabromodiphenylethane, 2,3-dichloropropyl phosphate, and aluminum hydroxide. The use of multiple flame retardants in synergy is more conducive to exerting their respective advantages and achieving a more efficient flame retardant effect.

[0029] According to some embodiments of the present invention, the mass of the flame retardant is 100% to 200% of the mass of the first polyol, for example, may be 150% to 200%.

[0030] According to some embodiments of the present invention, the chain extender is selected from one or more of 4,4'-methylenebis(2-chloroaniline), 1,4-butanediol, 1,6-hexanediol, glycerol, and ethylenediamine.

[0031] According to some embodiments of the present invention, the mass of the chain extender is 20% to 60% of the mass of the first polyol, specifically 20%, 25%, 30%, 25%, 40%, 45%, 50%, 55%, 60% or any value therebetween.

[0032] According to some embodiments of the present invention, the tackifier is selected from one or more of aldehyde-ketone resins, terpene resins, epoxy-modified polysiloxanes, polyester resins, or resins containing acidic groups. The present invention does not restrict the type of tackifier, and any common type in the art can be selected. Specifically, epoxy-modified polysiloxane can be Shin-Etsu KBM-4803; resins containing acidic groups, such as acrylic resins, alkyd resins, etc., in some embodiments, TOUCH CHEM AP-1 (acid value 70-90 mgKOH / g) of Malaysia Dazhi Chemical Co., Ltd. can be selected.

[0033] According to some embodiments of the present invention, the mass of the tackifier is 50% to 100% of the mass of the first polyol, specifically 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 100% or any value therebetween.

[0034] According to some embodiments of the present invention, the base material further includes at least one of a wetting agent, a defoaming agent, and a colorant.

[0035] According to some embodiments of the present invention, the wetting agent is selected from one or more of fluorocarbon modified polyacrylate (such as AFCONA-3750), sodium dodecyl sulfate, glycerol, and propylene glycol. The wetting agent can reduce the surface tension of the system, better wet the surface of the substrate, and improve adhesion.

[0036] According to some embodiments of the present invention, the mass of the wetting agent is 1% to 10% of the mass of the first polyol, specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or any value therebetween.

[0037] According to some embodiments of the present invention, the mass of the wetting agent is 2% to 8% of the mass of the first polyol.

[0038] Defoamers can reduce the generation of bubbles, reduce defects introduced by bubbles, and improve material performance and surface quality. The present invention does not restrict the type of defoamer. In some embodiments, the defoamer can be an organosilicon defoamer, such as AFCONA-S2685, or a non-organosilicon type, such as AFCONA-2021, a mineral oil type NXZ defoamer, etc.

[0039] According to some embodiments of the present invention, the mass of the defoaming agent is 1% to 5% of the mass of the first polyol, specifically 1%, 2%, 3%, 4%, 5% or any value therebetween.

[0040] According to some embodiments of the present invention, the colorant is selected from one or more of carbon black, iron oxide melanin, and aniline black.

[0041] According to some embodiments of the present invention, the mass of the colorant is 5% to 15% of the mass of the first polyol, and specifically can be 5%, 10%, 15% or any value therebetween.

[0042] According to some embodiments of the present invention, the flame retardant cold patch adhesive comprises the following preparation raw materials in parts by mass:

[0043] Base material: 100 parts of the first polyol, 100-200 parts of flame retardant, 20-60 parts of chain extender, 50-100 parts of tackifier, 1-10 parts of wetting agent, 1-5 parts of defoamer, 5-15 parts of colorant;

[0044] Curing agent: 100-500 parts.

[0045] It should be understood that in the raw material system of the present invention, the type or amount of the first polyol, flame retardant, chain extender, tackifier, or the amount of curing agent can be reasonably adjusted according to the known technology, and is not limited to the scope of the above embodiment. At the same time, according to the actual application needs, wetting agents, defoaming agents, colorants and other auxiliary agents can be further added, and the present invention does not impose any restrictive provisions on the type or amount of these components. Furthermore, it can be understood that the above-mentioned embodiments can be applied alone or in combination, and all belong to the protection scope of the present invention.

[0046] The second aspect of the present invention relates to a method for preparing the flame retardant cold patch adhesive, comprising: mixing the raw materials comprising the first polyol, flame retardant, chain extender, and tackifier to obtain the base material; mixing the modified MDI with the second polyol, reacting them, to obtain the curing agent.

[0047] The method has simple process, high production efficiency and is suitable for industrial application. In actual production, the prepared base material and curing agent are filled and sealed separately to make a two-component product. When used, the two components are mixed in a certain proportion and applied, which can achieve rapid curing. The cured material has low hygroscopicity and excellent comprehensive properties such as mechanical properties, flame retardancy and insulation. When used for repairing the outer sheath or insulation layer of the cable, it can improve the safety of the cable, especially the safety of the cable in a water environment and increase its service life.

[0048] According to some embodiments of the present invention, the raw materials for preparing the base material are mixed, wherein the mixing temperature is 105°C to 145°C.

[0049] According to some embodiments of the present invention, the raw materials for preparing the base material are mixed, wherein the mixing time is 2 to 5 hours, wherein a vacuum dehydration treatment may be performed during the mixing process.

[0050] According to some embodiments of the present invention, the reaction temperature is 80-100°C, specifically 80°C, 85°C, 90°C, 95°C, 100°C or any value therebetween.

[0051] According to some embodiments of the present invention, the reaction time is 2 to 4 hours, specifically 2 hours, 3 hours, 4 hours or any value therebetween.

[0052] The third embodiment of the present invention relates to the use of the flame retardant cold patch adhesive in repairing the outer sheath or insulation layer of a cable, wherein the insulation layer may be the insulation layer of a wire or cable of 10 kilovolts or less.

[0053] Using flame-retardant cold patch adhesive with low moisture absorption, high mechanical properties, high flame retardancy and high insulation for cable repair can significantly improve the insulation performance of the cable, reduce the risk of failure during underwater work, optimize mechanical properties and durability, while reducing repair costs, improving the long-term stability and safety of the cable, and meeting the cable maintenance and repair needs in different environments.

[0054] Herein, "plurality" includes two or more than two.

[0055] When it comes to numerical ranges, they include the end values ​​and any subset ranges within the range; the above include the number itself, for example, 2 and above include 2.

[0056] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 The sample strip of Example 1 is taken out after being immersed in water at 100° C. for 168 hours.

[0058] Figure 2 This is the state of the sample of Comparative Example 1 after being taken out from the water at 100°C for 168 hours. DETAILED DESCRIPTION

[0059] Embodiments of the present invention are described in detail below. The embodiments are exemplary and are only used to explain the present invention, but are not to be construed as limiting the present invention.

[0060] In the following examples, the relevant raw materials are described as follows:

[0061] Modified MDI: WANNATE CDMDI-1631, Wanhua Chemical, the mass percentage of isocyanate is 28%, and its composition information: MDI is 90wt%~70wt%, and carbodiimide modified MDI is 10wt%~30wt%.

[0062] Polycaprolactone diol: PCL-2200T from Polyren Chemical, molecular weight 2000, hydroxyl value 56±2mgKOH / g.

[0063] Aldehyde and ketone resin: BASF A81.

[0064] Epoxy modified polysiloxane: Shin-Etsu Chemical KBM4803.

[0065] Polytetramethylene glycol: PTEMG-2000, molecular weight 2000.

[0066] Defoaming agent: AFCONA-8265.

[0067] Wetting agent: AFCONA-3750.

[0068] Unless otherwise specified, the raw materials or equipment involved are conventional raw materials or equipment that can be purchased commercially.

[0069] Example 1

[0070] A flame retardant cold patch adhesive is prepared, comprising the following steps:

[0071] (1) Preparation of base material: At 115° C., 100 parts of polycaprolactone diol, 82 parts of antimony trioxide, 87 parts of decabromodiphenylethane, 56 parts of 4,4'-methylenebis(2-chloroaniline), 3 parts of defoamer, 5 parts of wetting agent, 72 parts of aldehyde-ketone resin, 16 parts of epoxy-modified polysiloxane, and 12 parts of N330 pigment carbon black powder were put into a reaction kettle, stirred and vacuumed for 4 hours, and then cooled to room temperature to obtain a base material.

[0072] (2) Preparation of prepolymer: 189 parts of polytetramethylene glycol and 89 parts of modified MDI were mixed, and then reacted at 90° C. for 3 h, and then cooled to room temperature to obtain a prepolymer.

[0073] (3) When in use, mix the base material and prepolymer in a weight ratio of 1:1 and prepare samples for testing.

[0074] Example 2

[0075] A flame retardant cold patch adhesive is prepared, comprising the following steps:

[0076] (1) Preparation of base material: 100 parts of polycaprolactone diol, 72 parts of antimony trioxide, 76 parts of decabromodiphenylethane, 24 parts of 2,3-dichloropropyl phosphate, 42 parts of 4,4'-methylenebis(2-chloroaniline), 3 parts of defoamer, 5 parts of wetting agent, 72 parts of aldehyde-ketone resin, 16 parts of epoxy-modified polysiloxane, and 9 parts of N330 pigment carbon black powder were put into a reaction kettle at 115°C, stirred and vacuumed for 4 hours, and cooled to room temperature to obtain a base material.

[0077] (2) Preparation of prepolymer: 189 parts of polytetramethylene glycol and 147 parts of modified MDI were mixed, and then reacted at 90° C. for 3 h, and then cooled to room temperature to obtain a prepolymer.

[0078] (3) When in use, mix the base material and prepolymer in a weight ratio of 10:7 and prepare samples for testing.

[0079] Example 3

[0080] A flame retardant cold patch adhesive is prepared, comprising the following steps:

[0081] (1) Preparation of base material: At 125° C., 100 parts of polycaprolactone diol, 84 parts of antimony trioxide, 86 parts of decabromodiphenylethane, 36 parts of 4,4'-methylenebis(2-chloroaniline), 4 parts of defoamer, 6 parts of wetting agent, 81 parts of aldehyde-ketone resin, 12 parts of epoxy-modified polysiloxane, and 12 parts of N330 pigment carbon black powder were added into a reaction kettle, stirred and vacuumed for 4 hours, and cooled to room temperature to obtain a base material.

[0082] (2) Preparation of prepolymer: 189 parts of polytetramethylene glycol and 89 parts of modified MDI were mixed, and then reacted at 90° C. for 3 h, and then cooled to room temperature to obtain a prepolymer.

[0083] (3) When in use, mix the base material and prepolymer in a weight ratio of 1:1 and prepare samples for testing.

[0084] Example 4

[0085] A flame retardant cold patch adhesive is prepared, comprising the following steps:

[0086] (1) Preparation of base material: 100 parts of polycaprolactone diol, 84 parts of antimony trioxide, 84 parts of decabromodiphenylethane, 38 parts of 4,4'-methylenebis(2-chloroaniline), 3 parts of defoamer, 7 parts of wetting agent, 76 parts of aldehyde-ketone resin, 16 parts of epoxy-modified polysiloxane, and 12 parts of N330 pigment carbon black powder were put into a reaction kettle at 135°C, stirred and vacuumed for 4 hours, and cooled to room temperature to obtain a base material.

[0087] (2) Preparation of prepolymer: 189 parts of polytetramethylene glycol and 89 parts of modified MDI were mixed, and then reacted at 90° C. for 3 h, and then cooled to room temperature to obtain a prepolymer.

[0088] (3) When in use, mix the base material and prepolymer in a weight ratio of 1:1 and prepare samples for testing.

[0089] Comparative Example 1

[0090] A flame retardant cold patch adhesive was prepared by referring to the method of Example 1, except that the polycaprolactone diol in step (1) was replaced by polyethylene adipate (Shandong Baihong New Materials Co., Ltd., HKP-2022 type, molecular weight 2000).

[0091] Comparative Example 2

[0092] A flame retardant cold patch adhesive was prepared by referring to the method of Example 1, except that the polycaprolactone diol in step (1) was replaced by polyoxypropylene diol (molecular weight 1000).

[0093] Comparative Example 3

[0094] The flame retardant cold patch adhesive was prepared by referring to the method of Example 1, except that the prepolymer preparation process of step (2) was not included. Step (2) was: 189 parts of polytetramethylene ether glycol and 89 parts of modified MDI were mixed to obtain a curing agent. Step (3) was: when used, the base material and the curing agent were mixed in a weight ratio of 1:1, and a sample was prepared for testing.

[0095] The test method is as follows:

[0096] Hygroscopicity: Cut the specimens into the following dimensions: (30-40) mm*25 mm*1 mm. Immerse the specimens in 100°C water for 168 h. Calculate the increase (%) in mass of the specimens after immersion relative to the mass before immersion.

[0097] Tensile strength, elongation at break: Test standard number: GB / T 528-2009, specimen type: dumbbell-shaped type 1 specimen, tensile rate: 500mm / min. Test performance at room temperature (25℃, the specimen was placed at the test temperature of 25±0.5℃ for 24h before testing) and 100℃ oven aging for 168h. The performance change rate after aging at 100℃ for 168h is the performance change range (%) relative to room temperature.

[0098] Breakdown strength: The test instrument is LJC-50E voltage breakdown tester produced by Beijing AVIC Dingli Instrument Equipment Co., Ltd.

[0099] Dielectric constant and dielectric loss tangent: The testing instrument is the QS37a insulation paper dielectric constant dielectric loss tester produced by Shanghai Peicheng Electronic Technology Development Co., Ltd.

[0100] Flame retardant properties: tested according to GB / T 10707-2008.

[0101] The test results of various embodiments and comparative examples are shown in Table 1.

[0102] Table 1

[0103]

[0104] It can be seen from Table 1 that the hygroscopicity of the rubber material of the embodiment of the present invention after immersion in water at 100°C for 168h is ≤4%, which is much lower than that of each comparative example; the change rate of tensile strength after aging at 100°C for 168h is significantly lower, and it has excellent tensile strength, elongation at break, resistance to wet and hot aging, and electrical insulation performance. In addition, the flame retardant grade tested is ≤FV-1, which meets the basic use requirements of cables.

[0105] The base material of Comparative Example 1 is polyethylene adipate glycol, in which the ester bond is more easily hydrolyzed and has poor water resistance; the base material of Comparative Example 2 is polyoxypropylene glycol, in which the ether bond has poor heat resistance. Therefore, the water resistance and heat resistance of Comparative Examples 1 and 2 are much lower than those of the embodiments. Figure 1 and Figure 2 , respectively, are the states of Example 1 and Comparative Example 1 after being taken out after being immersed in water at 100°C for 168h. It can be seen that the strip of Example 1 remains flat after being immersed in water, and is basically unchanged compared with before the test, while the strip of Comparative Example 1 has obviously curled and deformed. In addition, the base polyol of Comparative Example 2 has a high hydroxyl value and a fast reaction rate, which may make it difficult to form a high molecular weight cross-linking system. At the same time, the strength of the polyether segment itself is limited, resulting in poor mechanical properties of the material. At high temperatures, the ether bond breaks and cannot effectively prevent water molecules from penetrating. The dielectric loss tangent and dielectric constant of Comparative Examples 1 and 2 are higher than those of the embodiments, which is presumably related to the fluctuation of the hydroxyl value on the surface of the substrate. The high hydroxyl value and large polarity result in low electrical properties. The curing agent of Comparative Example 3 is not pre-made into a prepolymer, and the polycaprolactone diol and polytetramethylene glycol directly react rapidly with the modified MDI. The formed polyurethane has low crosslinking density, low strength, low elongation at break, poor mechanical properties, and cannot effectively prevent water molecules from penetrating into the coating film. The moisture absorption performance after immersion in water at 100°C for 168 hours is as high as 19%, which is much higher than that of the embodiment.

[0106] From the above results, it can be seen that the flame retardant cold repair adhesive of the embodiment of the present invention has better water resistance, heat resistance, mechanical properties, flame retardancy and electrical properties, and can better meet the maintenance and repair needs of cables in different environments (such as water-containing environments).

[0107] The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A flame retardant cold patch adhesive, characterized in that: The invention comprises a base material and a curing agent; wherein the base material comprises the following raw materials: a first polyol, a flame retardant, a chain extender, and a tackifier, wherein the first polyol is selected from one or two of polycaprolactone diol and polycaprolactone triol; The curing agent is a prepolymer of modified MDI and a second polyol; wherein the modified MDI includes carbodiimide-modified MDI; and the second polyol is selected from one or two of polytetramethylene ether polyol and terminal hydroxyl polybutadiene.

2. The flame retardant cold patch adhesive according to claim 1, characterized in that: In the curing agent, the mass percentage of isocyanate in the modified MDI is 20% to 30%; and / or, the modified MDI includes MDI and carbodiimide-modified MDI; and / or, the mass fraction of the carbodiimide-modified MDI in the modified MDI is ≥5%.

3. The flame retardant cold patch adhesive according to claim 1 or 2, characterized in that: In the curing agent, the second polyol includes polytetramethylene ether polyol; and / or the hydroxyl value of the second polyol is 40 to 70 mgKOH / g; and / or the mass ratio of the second polyol to modified MDI is 1:1 to 4:

1.

4. The flame retardant cold patch adhesive according to claim 1, characterized in that: The molecular weight of the first polyol is 1500 to 4500; and / or the mass of the curing agent is 100% to 500% of the mass of the first polyol.

5. The flame retardant cold patch adhesive according to claim 1, characterized in that: The flame retardant is selected from one or more of antimony trioxide, decabromodiphenylethane, 2,3-dichloropropyl phosphate, and aluminum hydroxide; and / or, the mass of the flame retardant is 100% to 200% of the mass of the first polyol; and / or, the chain extender is selected from one or more of 4,4'-methylenebis(2-chloroaniline), 1,4-butanediol, 1,6-hexanediol, glycerol, and ethylenediamine; and / or, the mass of the chain extender is 20% to 60% of the mass of the first polyol; and / or, the tackifier is selected from one or more of aldehyde-ketone resins, terpene resins, epoxy-modified polysiloxanes, polyester resins or resins containing acidic groups; And / or, the mass of the tackifier is 50% to 100% of the mass of the first polyol.

6. The flame retardant cold patch adhesive according to claim 1, characterized in that: The base material also includes at least one of a wetting agent, a defoaming agent and a coloring agent.

7. The flame retardant cold patch adhesive according to claim 6, characterized in that: The base material satisfies at least one of the following (1) to (6): (1) The wetting agent is selected from one or more of fluorocarbon modified polyacrylate, sodium dodecyl sulfate, glycerol, and propylene glycol; (2) The mass of the wetting agent is 1% to 10% of the mass of the first polyol; (3) The defoaming agent is silicone or non-silicone; (4) The mass of the defoaming agent is 1% to 5% of the mass of the first polyol; (5) The colorant is selected from one or more of carbon black, iron oxide melanin, and aniline black; (6) The mass of the colorant is 5% to 15% of the mass of the first polyol.

8. The flame retardant cold patch adhesive according to claim 1, characterized in that: The flame retardant cold patch adhesive comprises the following raw materials in parts by mass: Base material: 100 parts of the first polyol, 100-200 parts of flame retardant, 20-60 parts of chain extender, 50-100 parts of tackifier, 1-10 parts of wetting agent, 1-5 parts of defoamer, 5-15 parts of colorant; Curing agent: 100-500 parts.

9. The method for preparing the flame retardant cold patch adhesive according to any one of claims 1 to 8, characterized in that: include: Mixing the raw materials including the first polyol, a flame retardant, a chain extender, and a tackifier to obtain the base material; The modified MDI is mixed with a second polyol and reacted to obtain the curing agent.

10. Use of the flame retardant cold repair adhesive according to any one of claims 1 to 8 in repairing the outer sheath or insulation layer of a cable.

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