High-polarity thermoplastic elastomer for lining of fire hose as well as preparation method and application of high-polarity thermoplastic elastomer

Abstract

The invention discloses a high-polarity thermoplastic elastomer for a lining of a fire hose as well as a preparation method and application of the high-polarity thermoplastic elastomer. The elastomer raw material comprises 10-40 parts of a styrene block copolymer; 15 to 30 parts of polypropylene resin; 20 to 60 parts of a glycidyl methacrylate grafted polyolefin elastomer; 10 to 50 parts of processing oil; and 0.1-2 parts of an auxiliary agent. By introducing the high-activity epoxy group graft, a'physical interpenetration-chemical bonding 'dual-interface enhancement mechanism is constructed, the surface energy and polarity of a base material are remarkably improved, and the problems that traditional TPE is low in bonding strength with polar hot melt adhesive and a fiber layer and prone to layering under high pressure are thoroughly solved. After the material is subjected to hot-pressing compounding, the surface water contact angle is lower than 70 degrees, the peel strength with TPU hot melt adhesive reaches 42 N / 25 mm or above, the elongation at break is larger than 600%, and brittle rupture at the temperature of 48 DEG C below zero is avoided. The preparation method disclosed by the invention can ensure uniform distribution and high retention of polar functional groups, and is suitable for industrial manufacturing of high-performance and light-weight fire hose liners.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high polymer material science and engineering, in particular to a high-polarity thermoplastic elastomer (TPE) for fire hose lining, its preparation method and application. More specifically, the present application relates to a styrene-based thermoplastic elastomer endowed with high surface activity and polarity by reactive grafting modification technology, which can form a firm chemical bond with polyurethane (TPU) hot melt adhesive and polyester fabric. BACKGROUND

[0002] Fire hose is an indispensable key equipment in urban public fire fighting, forest fire fighting and industrial fire fighting system, mainly used for conveying high-pressure water flow or foam extinguishing agent. With the improvement of modern fire fighting demand, fire hose is developing towards high pressure, light weight, strong weather resistance and long service life. Fire hose is usually composed of an inner lining and an outer woven layer: the outer woven layer (usually woven by high-strength polyester filament and polypropylene filament) provides pressure strength and wear protection; the inner lining is responsible for leakage prevention, fluid transportation and chemical corrosion resistance. The performance of the inner lining directly determines the flexibility, low temperature resistance and reliability of the hose in extreme environments.

[0003] At present, the main fire hose lining materials on the market mainly include polyvinyl chloride (PVC), thermoplastic polyurethane (TPU) and rubber (such as EPDM) and the like.

[0004] Polyvinyl chloride (PVC): PVC molecular chain contains strong polar chlorine atoms (C-Cl bond), has high surface energy, is easy to bond with polar adhesives (such as polyurethane adhesive), and has low raw material cost and mature processing technology. However, PVC material has obvious defects: poor low temperature resistance, high glass transition temperature (Tg), easy to harden and brittle fracture in northern winter or high cold area (-20℃ or below), resulting in difficulty in unfolding or folding of the hose. In addition, a large amount of phthalate plasticizer (such as DOP, DINP) is often added in PVC formula, which not only may have reproductive toxicity, but also is easy to migrate to the surface over time, resulting in material aging and hardening. In the high temperature environment of fire scene, PVC combustion will release corrosive gases such as hydrogen chloride (HCl) and toxic dioxins, causing secondary harm to firefighters and the environment.

[0005] Thermoplastic polyurethane (TPU): TPU lining has excellent wear resistance, oil resistance, high strength and good low temperature resistance (up to -50℃), and is non-toxic and environmentally friendly. However, TPU raw material is expensive, the processing window is narrow, and the precision of the extrusion equipment is high, resulting in high cost of finished hose, which is difficult to popularize in grassroots fire stations and large-scale agricultural irrigation fields.

[0006] Traditional thermoplastic elastomers (TPEs): TPE materials based on styrene-ethylene / butene-styrene block copolymers (SEBS) combine the high elasticity of rubber with the processing convenience of plastics. Their molecular structure is saturated, exhibiting excellent weather resistance and aging resistance, and they have a low density (approximately 0.9 g / cm³, 30% lighter than PVC), and are non-toxic and environmentally friendly. However, SEBS is a typical non-polar polyolefin material with low surface energy and strong chemical inertness. In fire hose manufacturing, the inner lining layer needs to be firmly bonded to the outer braided layer using hot melt adhesive (usually polar TPU hot melt adhesive). According to the principle of "like dissolves like," the interfacial compatibility between non-polar TPE and highly polar TPU hot melt adhesive is poor, making it difficult to form effective intermolecular forces, resulting in low peel strength. In actual use, the impact of high-pressure water flow and repeated bending and folding of the hose can easily cause delamination (peeling) between the inner and outer layers, leading to bulging and bursting of the hose, posing serious safety hazards.

[0007] To improve the adhesive properties of TPE, existing technologies mainly use maleic anhydride (MAH)-grafted polyolefins (POE-g-MAH) as compatibilizers. However, this method has the following limitations:

[0008] 1. Limited reactivity: The reaction rate between the anhydride groups and the urethane groups in TPU is relatively slow and requires a high activation energy.

[0009] 2. Prone to hydrolysis and failure: The anhydride group easily absorbs moisture from the air and undergoes hydrolysis to generate dicarboxylic acids, resulting in a decrease in polarity and poor material inventory stability.

[0010] 3. Odor and color issues: When the MAH grafting rate is too high, it can easily cause the material to turn yellow and produce an irritating odor.

[0011] Therefore, developing a novel lining material that retains the excellent physical properties of SEBS-based TPE while also possessing high surface polarity and the ability to form chemical bonds with TPU hot melt adhesive is a technological bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0012] The purpose of this invention is to provide a high polarity thermoplastic elastomer for fire hose linings, its preparation method, and its application.

[0013] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0014] A highly polar thermoplastic elastomer for use as a lining for fire hoses, comprising the following components in parts by weight:

[0015] 10-40 parts of styrene block copolymer (SEBS);

[0016] Polypropylene resin (PP) 15-30 parts;

[0017] 20-60 parts of glycidyl methacrylate (GMA) grafted polyolefin elastomer (POE-g-GMA);

[0018] 10-50 parts of processing oil;

[0019] Additives: 0.1-2 parts.

[0020] A further technical solution is that the styrene-butadiene-styrene block copolymer (SEBS) is a hydrogenated styrene-butadiene-styrene block copolymer with a narrow molecular weight distribution, a styrene block content of 20-35%, and a Shore A hardness of 60-75; the test conditions are 230℃ and 5kg, the melt mass flow rate is 2-10g / 10min, and its molecular structure is at least one of linear or star structure.

[0021] In a further technical solution, the polypropylene resin (PP) is selected from at least one of homopolymer polypropylene (PPH) or random copolymer polypropylene (PPR); the test conditions are 230℃ and 2.16kg, the melt flow rate is 2~15g / 10min, and the flexural modulus is 1000~1600MPa.

[0022] In a further technical solution, the glycidyl methacrylate (GMA) grafted polyolefin elastomer (POE-g-GMA) has a matrix resin of ethylene-octene copolymer (POE) or ethylene-butene copolymer, wherein the co-molar content of octene or butene is 20-40%, and the grafting rate of glycidyl methacrylate (GMA) is 0.5-5.0 wt% by weight.

[0023] In a further technical solution, the processing oil is selected from paraffin oil or naphthenic oil, and its kinematic viscosity at 40°C is 70~120 mmHg. 2 High viscosity oils have a flash point greater than 200℃ and an aromatic hydrocarbon content of less than 1%. High viscosity oils can reduce volatilization during high-temperature processing and reduce the risk of oil separation during long-term storage of finished products.

[0024] A further technical solution is provided, wherein the additives include antioxidants, light stabilizers, and lubricants; wherein the antioxidant is selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), or a mixture thereof, in a mixing ratio of 1:1 to 1:2; the lubricant is selected from at least one of calcium stearate and zinc stearate.

[0025] Furthermore, the present invention also discloses a method for preparing a high-polarity thermoplastic elastomer for fire hose linings, comprising:

[0026] Step 1: Polyolefin elastomer (POE), glycidyl methacrylate (GMA) monomer, and initiator dicumyl peroxide (DCP) are mixed in a ratio of 100:2.5:0.5 and subjected to a grafting reaction in a twin-screw reactive extruder. The extruder temperature is set within the range of 150~200℃, and the screw speed is 300~500rpm. After the reaction, the product is vacuum devolatilized and pelletized to obtain glycidyl methacrylate (GMA) grafted polyolefin elastomer (POE-g-GMA).

[0027] Step 2: In a mixer, at a speed of 800-1000 rpm, add 10-40 parts of styrene block copolymer (SEBS) and 10-50 parts of processing oil, mix for 3-5 minutes, and use frictional heat to allow the oil to fully penetrate and swell the styrene block copolymer (SEBS) molecular chains. After mixing, let stand for 12 hours.

[0028] Step 3: Adjust the mixer speed to 400-500 rpm, add 15-30 parts of the oil-soaked styrene block copolymer (SEBS) and polypropylene resin (PP), 20-60 parts of the glycidyl methacrylate (GMA) grafted polyolefin elastomer (POE-g-GMA) prepared in Step 1, and 0.1-2 parts of additives, mix for 3-5 minutes, and control the mixing temperature at 80-90℃;

[0029] Step 4: Add the mixture obtained in Step 3 to a co-rotating twin-screw extruder with a length-to-diameter ratio (L / D) of 40-48 for melt blending; the twin-screw extruder is set to the following temperature ranges: feeding section 140-160℃, compression section 170-185℃, metering section 190-200℃, and die head 195-185℃; the main extruder speed is 300-600 rpm.

[0030] Step 5: The extruded material is granulated underwater or in strips, then centrifuged, dehydrated, vibrated, sieved, and dried with hot air at 60-80°C to obtain the aforementioned high-polarity thermoplastic elastomer for fire hose lining.

[0031] In the above scheme, step one is reactive grafting. In a twin-screw extruder, a free radical initiator (DCP) initiates the grafting reaction of GMA monomers onto the POE backbone. The reaction temperature (150~200℃) and residence time are strictly controlled to avoid POE backbone breakage or excessive crosslinking.

[0032] Step two involves first mixing SEBS and white oil at high speed. High shear frictional heat (60-80℃) is used to allow oil molecules to penetrate more fully into the polybutadiene phase of SEBS. After mixing, the mixture is allowed to stand for 12 hours, then PP+POE-g-GMA is added and mixed at low speed. This avoids premature ring-opening or volatilization of GMA functional groups due to high temperatures.

[0033] Step 3 involves twin-screw reactive blending. A high aspect ratio (L / D 40~48) extruder is used to achieve fine dispersion of each component.

[0034] Step four involves underwater pelletizing, dehydration, and drying to obtain high-polarity TPE finished particles.

[0035] In a further technical solution, in step one, the amount of the initiator dicumyl peroxide (DCP) added is 0.1-0.3% of the mass of the polyolefin elastomer (POE), and the amount of glycidyl methacrylate (GMA) monomer added is 1.0-6.0% of the mass of the polyolefin elastomer (POE); the twin-screw extruder uses a special screw combination, and at least three sets of kneading block elements are set in the reaction section to enhance shear dispersion. Further technical solutions...

[0036] Furthermore, the present invention also discloses an application of a highly polar thermoplastic elastomer for the preparation of inner linings for fire hoses, industrial oil hoses, and agricultural irrigation hoses.

[0037] A further technical solution involves using a highly polar thermoplastic elastomer as an inner lining material for thermal bonding with highly polar hot melt adhesives (such as TPU hot melt adhesives and copolyester hot melt adhesives).

[0038] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0039] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this case.

[0040] The working principle and advantages of this invention are as follows:

[0041] This invention provides a high-polarity thermoplastic elastomer for fire hose linings, its preparation method, and its application. The elastomer composition comprises a styrene-based block copolymer (SEBS), polypropylene resin (PP), a glycidyl methacrylate (GMA) grafted polyolefin elastomer (POE-g-GMA), processing oils, and additives.

[0042] The elastomer of this invention solves the problems of poor adhesion and low peel strength between existing thermoplastic elastomer linings and polar hot melt adhesives, while maintaining excellent low-temperature resistance and mechanical properties. Testing shows that its T-peel strength with TPU hot melt adhesive can reach 42-53 N / 25 mm, meeting the requirements of high-pressure fire hoses for interlayer bonding strength.

[0043] In the elastomer of this invention, the polystyrene hard segment microdomains of SEBS provide physical crosslinking points, imparting strength and resilience to the material; its ethylene-butene soft segment contributes flexibility and low-temperature resistance. SEBS with a styrene content of 20-35% is preferred to balance modulus and elasticity. POE-g-GMA, as a key polarity modifier, significantly enhances the surface polarity of the material due to its highly active epoxy groups; due to its good compatibility with the SEBS soft segment, POE-g-GMA tends to distribute on the surface during blending, thereby enhancing interfacial affinity with polar hot melt adhesives. PP, as a hard phase modifier, is used to regulate overall strength, processing fluidity, and heat resistance, and is well compatible with the SEBS middle segment and POE component, contributing to the formation of an interpenetrating network structure and improving the burst pressure resistance of the lining.

[0044] Compared to existing technologies, the material of this invention also has the following comprehensive advantages: it contains no unsaturated double bonds, exhibiting excellent resistance to ozone and ultraviolet radiation; its low-temperature brittleness temperature can be as low as -48°C, ensuring it remains flexible and crack-free even in extremely cold environments; it is free of halogens, phthalates, and heavy metals, complying with environmental regulations; and it produces low smoke and no corrosive gases during combustion. Furthermore, the material has high melt strength, making it suitable for efficient molding processes such as extrusion blow molding or cast extrusion to prepare water hose liners.

[0045] In summary, this invention introduces GMA grafts containing highly reactive epoxy groups to construct a dual interface reinforcement mechanism of "physical interpenetration-chemical bonding," significantly improving the surface energy and polarity of non-polar TPE substrates. This completely solves the problems of low adhesion strength and easy delamination under high pressure when traditional TPE is bonded to polar TPU hot melt adhesives and polyester fiber layers. Experiments show that after hot-pressing lamination, the surface water contact angle of this material can be reduced to below 70°, and the T-peel strength with TPU hot melt adhesive reaches over 42N / 25mm. It also possesses excellent flexibility (elongation at break > 600%) and low-temperature resistance (no brittleness at -48℃). This invention also discloses a "stepwise premixing-reactive extrusion" preparation process including specific rotation speed and temperature curves, which ensures uniform distribution and high retention of polar functional groups in the matrix, making it suitable for the industrial manufacturing of high-performance, lightweight fire hose liners. Detailed Implementation

[0046] The present invention will be further described below with reference to embodiments:

[0047] The present case will be clearly described in detail below. Any person skilled in the art who understands the embodiments of the present case can make changes and modifications based on the technology taught in the present case without departing from the spirit and scope of the present case.

[0048] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0049] The specifications of the raw materials used in this case are as follows:

[0050] SEBS: Kraton G1652 (USA), 30% styrene content, linear structure.

[0051] PP: Homopolymer polypropylene, Sinopec PPH-T03, MFR=3.0g / 10min.

[0052] POE: Dow Chemical Engage 8150, density 0.868 g / cm³ (for homemade grafting materials).

[0053] POE-g-GMA (self-made): The substrate is Engage8150, and the GMA grafting rate is 1.2%.

[0054] Processing oil: 100# white oil, flash point 225℃.

[0055] Additives: Antioxidant 1010 and 168 are compounded in a 1:1 ratio.

[0056] The preparation process of POE-g-GMA is as follows:

[0057] 100 kg of POE particles, 2.5 kg of GMA monomer, and 0.2 kg of DCP (dissolved in a small amount of acetone) were mixed evenly in a high-speed mixer and allowed to stand for 4 hours to allow the monomer to be absorbed. The mixture was then fed into a co-rotating twin-screw reactive extruder (L / D=48). Temperature settings: Zone 1: 140℃, Zone 2: 160℃, Reaction Zones (Zones 3 to 8): 180~200℃, Deviation Zones (Zones 9 to 10): 190℃, Die Head: 180℃. Screw speed: 400 rpm, Vacuum: -0.08 MPa. The mixture was pelletized underwater and centrifuged to obtain the POE-g-GMA graft. Titration determined the GMA grafting rate to be 1.2 wt%.

[0058] Examples 1-5: A highly polar thermoplastic elastomer for fire hose lining, composed of the following components in parts by weight, as shown in Table 1.

[0059] Table 1 Examples 1-5 (Unit: parts by weight)

[0060]

[0061] The preparation method is as follows:

[0062] Step 1: In a high-speed mixer, set the speed to 800 rpm. First, add the prescribed amounts of SEBS and processing oil, mix for 4 minutes, and let stand for 12 hours.

[0063] Step 2: Mixer speed 400 rpm. Add PP granules, POE-g-GMA granules and additives, continue mixing for 3 minutes, then discharge.

[0064] Step 3: Add the mixture to the co-rotating twin-screw extruder. Temperature settings: Zone 1 150℃, Zone 2 170℃, Zone 3 180℃, Zone 4 190℃, Zone 5 200℃, Zone 6 210℃, Zone 7 210℃, Die head 200℃. Rotation speed: Main extruder speed 450 rpm, feed speed 35 rpm. Turn on the vacuum pump, pressure -0.08 MPa, to remove residual small molecules and moisture.

[0065] Step 4: The extruded sample is cooled in a 30℃ cooling water bath, dried by an air knife, granulated by a pelletizer, and dried in a 70℃ hot air oven for 2 hours before packaging.

[0066] Comparative Examples 1-4:

[0067] To highlight the unique advantages of the POE-g-GMA and formulation system of this invention, the following comparative examples were set up (Table 2).

[0068] Table 2: Raw material formulas for Comparative Examples 1-4 (Unit: parts by weight)

[0069]

[0070] Comparative Example 1 replaced POE-g-GMA with an equal amount of POE-g-MAH (maleic anhydride grafting rate of 1.1%) to verify the effect of functional group type. Comparative Example 2 replaced it with ungrafted pure POE to simulate ordinary nonpolar TPE. Comparative Example 3 used a typical high-oil-extended SEBS soft rubber formulation, without PP and POE, to verify the basic TPE properties.

[0071] Performance tests are as follows:

[0072] Hardness: Tested according to GB / T531.1, and the average value of 5 points is taken.

[0073] Tensile strength and elongation at break: tested according to GB / T528, tensile speed 500 mm / min.

[0074] Water contact angle: The particles are pressed into a smooth thin sheet at 190℃, and the static contact angle is measured by adding 2μL of deionized water using a contact angle meter. The smaller the angle, the higher the polarity.

[0075] T-peel strength test: Commercially available TPU-based hot melt adhesive granules were hot-pressed into a 0.2 mm film at 180°C as the adhesive layer. A 25 mm wide strip of this TPU hot melt adhesive film was cut and sandwiched between the TPE sheet and polyester fabric to be tested. The TPE sheet, TPU hot melt adhesive film, and polyester fabric were bonded together at 120°C and 0.2 MPa for 300 seconds, and then cooled under standard conditions (23°C, 50% RH) for 24 hours. The peel strength was tested on a universal testing machine at a speed of 50 mm / min according to ASTM D1876 (T-peel test).

[0076] Low-temperature embrittlement temperature: Tested according to GB / T5470-2008.

[0077] Examples 1-5 and Comparative Examples 1-3 were tested, and the test data are shown in Table 3.

[0078] Table 3 Test Results

[0079]

[0080] The results are analyzed as follows:

[0081] Compared to unmodified POE (Comparative Example 2), the water contact angle of each embodiment decreased significantly, and the surface changed from hydrophobic to hydrophilic. The peel strength jumped from 10.5 N / 25 mm to over 42 N / 25 mm, reaching a maximum of 52.2 N / 25 mm (Example 4).

[0082] Under the same matrix formulation, the peel strength of the GMA-grafted system (Example 3) was significantly higher than that of the MAH-grafted system (Comparative Example 1). This is because the epoxy groups of GMA have a significantly higher reactivity (ring-opening addition) with the urethane groups in TPU than the anhydride groups of MAH (acylation reaction), and the resulting chemical bonds are more stable. In addition, the GMA-modified material has a lighter color and no pungent acidic odor.

[0083] The material of this invention has a low-temperature embrittlement temperature as low as -48°C. This means that in cold environments, the hose of this invention remains flexible and foldable, while PVC hoses face the risk of cracking. The elongation at break of this invention is greater than 600%, which can give the hose better flexural fatigue life.

[0084] In summary, this invention has successfully prepared an inner lining material with excellent comprehensive performance. While maintaining the high elasticity and low-temperature resistance of TPE, this material achieves super-strong adhesion to polar TPU hot melt adhesive through the "chemical anchoring" effect of GMA epoxy functional groups, with a peel strength consistently ranging from 42 to 53 N / 25 mm. This solves the long-standing TPE adhesion problem plaguing the industry and is an ideal upgrade product to replace PVC and TPU inner linings.

[0085] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-polarity thermoplastic elastomer for use as a lining for fire hoses, characterized in that: Its raw materials include the following components in parts by weight: 10-40 parts of styrene block copolymers; 15-30 parts of polypropylene resin; 20-60 parts of glycidyl methacrylate-grafted polyolefin elastomer; 10-50 parts of processing oil; Additives: 0.1-2 parts.

2. The high polarity thermoplastic elastomer for fire hose lining according to claim 1, characterized in that: The styrene-block copolymer is a hydrogenated styrene-butadiene-styrene block copolymer with a styrene block content of 20-35% and a Shore A hardness of 60-75. The test conditions are 230℃ and 5kg, with a melt mass flow rate of 2-10g / 10min. Its molecular structure is at least one of linear or star structure.

3. The high polarity thermoplastic elastomer for fire hose lining according to claim 1, characterized in that: The polypropylene resin is selected from at least one of homopolymer polypropylene or random copolymer polypropylene; the test conditions are 230℃, 2.16kg, melt flow rate of 2~15g / 10min, and flexural modulus of 1000~1600MPa.

4. A high-polarity thermoplastic elastomer for fire hose lining according to claim 1, characterized in that: In the glycidyl methacrylate-grafted polyolefin elastomer, the matrix resin is an ethylene-octene copolymer or an ethylene-butene copolymer, wherein the co-molar content of octene or butene is 20-40%, and the grafting rate of glycidyl methacrylate is 0.5-5.0 wt% by weight.

5. A high-polarity thermoplastic elastomer for fire hose lining according to claim 1, characterized in that: The processing oil is selected from paraffin oil or naphthenic oil, and its kinematic viscosity at 40°C is 70~120 mmHg. 2 / s, flash point greater than 200℃, aromatic hydrocarbon content less than 1%.

6. A high-polarity thermoplastic elastomer for fire hose lining according to claim 1, characterized in that: The additives include antioxidants, light stabilizers, and lubricants; wherein the antioxidant is selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl]phosphite, or a mixture thereof, in a mixing ratio of 1:1 to 1:2; the lubricant is selected from at least one of calcium stearate and zinc stearate.

7. A method for preparing a high-polarity thermoplastic elastomer for fire hose linings, characterized in that: The method for preparing a high-polarity thermoplastic elastomer for fire hose lining as described in any one of claims 1 to 6 comprises: Step 1: Mix polyolefin elastomer, glycidyl methacrylate monomer, and initiator dicumyl peroxide in a ratio of 100:2.5:0.5, and carry out the grafting reaction in a twin-screw reactive extruder. The extruder temperature is set within the range of 150~200℃, and the screw speed is 300~500rpm. After the reaction, the polyolefin elastomer grafted with glycidyl methacrylate is obtained by vacuum devolatilization and pelletizing. Step 2: In a mixer, at a speed of 800-1000 rpm, add 10-40 parts of styrene block copolymer and 10-50 parts of processing oil, mix for 3-5 minutes, and use frictional heat to allow the oil to fully penetrate and swell the molecular chains of styrene block copolymer. After mixing, let stand for 12 hours. Step 3: Adjust the mixer speed to 400-500 rpm, add 15-30 parts of the oil-soaked styrene block copolymer and polypropylene resin, 20-60 parts of the glycidyl methacrylate-grafted polyolefin elastomer prepared in Step 1, and 0.1-2 parts of additives, mix for 3-5 minutes, and control the mixing temperature at 80-90℃. Step 4: Add the mixture obtained in Step 3 to a co-rotating twin-screw extruder with a length-to-diameter ratio of 40-48 for melt blending; the twin-screw extruder is set to the following temperature ranges: feeding section 140-160℃, compression section 170-185℃, metering section 190-200℃, and die head 195-185℃; the main extruder speed is 300-600 rpm. Step 5: The extruded material is granulated underwater or in strips, then centrifuged, dehydrated, vibrated, sieved, and dried with hot air at 60-80°C to obtain the aforementioned high-polarity thermoplastic elastomer for fire hose lining.

8. The method for preparing a high-polarity thermoplastic elastomer for fire hose lining according to claim 7, characterized in that: In step one, the amount of the initiator dicumyl peroxide added is 0.1~0.3% of the mass of the polyolefin elastomer, and the amount of glycidyl methacrylate monomer added is 1.0~6.0% of the mass of the polyolefin elastomer; the twin-screw extruder is equipped with at least three sets of kneading block elements in the reaction section to enhance shear dispersion.

9. An application of a highly polar thermoplastic elastomer, characterized in that: The high polarity thermoplastic elastomer for fire hose lining described in any one of claims 1 to 6 is applied to the preparation of the inner lining layer of fire hoses, industrial oil hoses, and agricultural irrigation hoses.

10. The application of a high-polarity thermoplastic elastomer according to claim 9, characterized in that: High-polarity thermoplastic elastomers are used as lining materials for thermal bonding with high-polarity hot melt adhesives.

Images