A highly flame-retardant foamed modified styrene thermoplastic elastomer and preparation method thereof

Abstract

The invention discloses a highly flame-retardant foaming modified styrene thermoplastic elastomer and a preparation method thereof, which belongs to the field of materials, and the raw materials for preparation include thermoplastic elastomer, polyolefin, solvent oil, macromolecular flame retardant, foaming agent, foaming promoter and crosslinking agent; the macromolecular flame retardant is polyphosphinosilazane; the solvent oil includes cycloalkane oil and epoxy soybean oil; the epoxy soybean oil modifies the foaming agent to obtain the epoxy soybean oil modified foaming agent; the epoxy soybean oil modified foaming agent is then mixed with thermoplastic elastomer, polyolefin, cycloalkane oil, polyphosphinosilazane, foaming promoter and crosslinking agent to obtain the highly flame-retardant foaming modified styrene thermoplastic elastomer. The macromolecular flame retardant in the invention is halogen-free and non-toxic and can form an interpenetrating network structure with the molecular chain of the matrix material, improve the compatibility with the matrix, significantly improve its flame retardant properties, and can also improve its impact strength and resilience.

Description

Technical Field

[0001] The invention belongs to the field of materials, and relates to a material for decorative purposes, in particular to a highly flame-retardant foamed modified styrene thermoplastic elastomer and a preparation method thereof. Background Art

[0002] Traditional styrene thermoplastic elastomers (SBS, SIS) contain a certain amount of unsaturated double bonds, which makes their heat resistance, weather resistance and anti-aging performance poor. In order to improve the above properties, they are usually hydrogenated to reduce the double bond content. For example, SEBS is obtained by hydrogenation of poly (styrene-butadiene-styrene), and the degree of hydrogenation can reach 80-90%. Its molecular structure contains both hard segments (PS) and soft segments (PEB). The hard segments play the role of "physical crosslinking points" to improve the rigidity of the molecular chain, while the soft segments make it easier to adjust the conformation of the molecular chain and give the polymer good flexibility. At the same time, the hard segment PS is distributed in the flexible PEB block to form a network crosslinking structure, which improves the thermal stability of the polymer. The polymer can be plasticized and molded like a thermoplastic resin at high temperature, and has the elasticity of cross-linked rubber at room temperature, thus becoming a new type of thermoplastic elastomer (TPE), showing a series of good properties such as high elasticity, good toughness, low density, non-toxicity, anti-aging, electrical insulation and thermoplastic molding. This elastomer has been widely used in the fields of culture and sports, interior decoration, automobile interior, sealing and shockproof, and medical treatment because it has excellent properties such as the plasticity of thermoplastics and the high elasticity of rubber. However, the existing SEBS material is a linear polymer, which is easy to produce plastic deformation under external loads, has the problems of low impact absorption performance, large compression permanent deformation, and poor resilience, and organic materials are generally flammable.

[0003] In order to further give SEBS more performance, it is necessary to add relevant additives to modify it. For example, in view of the problem of low mechanical properties and insufficient resilience of SEBS, patent application CN102585427A discloses a method for preparing a SEBS cross-linked elastomer composite material, by adding an appropriate amount of initiator dicumyl peroxide (DCP) during processing, initiating SEBS and PP free radical polymerization, and performing micro-crosslinking modification on it, so that the molecular chain forms a cross-linked network structure, reducing the slip ability of the molecular chain. After chemical crosslinking, SEBS can improve the ability to withstand tension, pressure and shear force, enhance the tensile strength of the material, reduce the permanent deformation of the material, and broaden the application range of SEBS. Patent application CN107880472A discloses a method for preparing a high-strength modified SEBS nanocomposite material, using a coupling agent to surface modify nano-silicon dioxide, which can effectively improve the dispersibility of nano-silicon dioxide in the SEBS matrix and reduce its agglomeration phenomenon. Modifying SEBS in combination with polypropylene can achieve the purpose of high transparency, high strength and low shrinkage of SEBS material. The modified SEBS nanocomposite material samples have a soft texture and good touch, and can be used as automotive interior surface materials.

[0004] In view of the problem of poor impact resistance, a patent application discloses the use of foaming technology to modify it so that it can absorb part of the energy when it is impacted by an external load. For example, patent application CN109251464B discloses a SEBS composite foam material, that is, SEBS, softening oil, EPDM and diisopropylbenzene peroxide, azodicarbonamide foaming agent, zinc oxide, zinc stearate, EVA, POE are put into a mixer for mixing, and then heat dissipation and granulation are carried out. The granulated material is put into an injection machine for foaming. The hardness of the SEBS composite foam material can reach 50, the rebound performance can reach 66%, and the compression resistance can reach 26%. This method effectively improves its impact absorption and rebound performance. However, the AC foaming agent itself is a solid particle with a large molecular polarity, and the matrix materials SEBS, PE, and PP are all non-polar molecules. Therefore, the AC foaming agent is not easy to be directly and evenly dispersed in SEBS, and the compatibility between the AC foaming agent and the matrix is ​​not ideal.

[0005] In order to improve the flame retardant properties of SEBS, patent application CN101974196B (a flame retardant composite material of a high oil-containing thermoplastic elastomer SEBS and its preparation method) discloses adding inorganic powder flame retardants aluminum hydroxide, magnesium hydroxide, silicon dioxide, ammonium polyphosphate, triisopropylphenyl phosphate, and decabromodiphenylethane to SEBS to prepare a composite material to achieve the purpose of flame retardancy. However, there is an interface incompatibility problem between the inorganic powder and the organic SEBS, and the surface of the inorganic powder is not modified, and the mechanical properties of the material will decrease as the amount of addition increases. Similarly, patent application CN102850752B discloses a method for preparing a flame retardant SEBS modified polycarbonate alloy material, using metal oxide molybdenum trioxide and halogen-containing flame retardant decabromodiphenylethane to achieve the purpose of synergistic flame retardancy. However, halogen-containing decabromodiphenylethane has the problem of environmental pollution. Patent application CN102146193B (Halogen-free flame-retardant thermoplastic elastomer composite based on SEBS) achieves the purpose of flame retardancy by adding ingredients such as melamine cyanurate, zinc borate, melamine polyphosphate, and organic hypophosphite. The compatibility between the flame retardant and the polymer matrix is ​​improved by adding flame retardant plasticizers and compatibilizers. However, this type of flame retardant is easy to decompose into toxic cyanide at high temperature, polluting the environment and endangering human health.

[0006] Patent application CN102702663B discloses a halogen-free flame retardant SEBS thermoplastic elastomer composition and its preparation method. By adding two flame retardants, magnesium hydroxide and boron-containing phenylphosphonate, and other additives to SEBS, a twin-screw machine is used for melting, mixing, extrusion, cooling, pelletizing, and drying to obtain the product, the purpose of synergistic flame retardancy and plasticization is achieved, and the mechanical properties and processing properties of the halogen-free flame retardant SEBS thermoplastic elastomer composition are significantly improved. Patent application CN106280200A adds magnesium hydroxide and phosphorus flame retardant to thermoplastic elastomer SEBS to prepare a composite material with good elasticity, high temperature resistance, and aging resistance. When flame retardant, it has the advantages of low smoke production, halogen-free, non-toxic, odor-free, environmentally friendly and pollution-free. On this basis, patent application CN106398084A further added thermoplastic polyphenylene ether PPO, and the thermoplastic low-smoke halogen-free flame retardant material prepared with PPO and SEBS as the base material has significantly improved low-temperature resistance, thermoplasticity, high-temperature resistance and corrosion resistance, which not only reduces production costs and pollution, but also has good environmental adaptability.

[0007] When SEBS is used for interior and vehicle decoration, it needs to meet the requirements of high resilience, high impact resistance and good flame retardancy. However, the existing SEBS can only meet part of the requirements, and there is room for further synergy and efficiency. Summary of the invention

[0008] The purpose of the present invention is to provide a highly flame-retardant foamed modified styrene thermoplastic elastomer and a preparation method thereof in view of the problems existing in the prior art, and to modify SEBS by combining micro-crosslinking, micro-foaming technology and macromolecular flame retardant polyphosphinosilazane to achieve high resilience, high impact resistance, high flame retardancy, and improve the comfort and safety of use. The highly flame-retardant foamed modified styrene thermoplastic elastomer can be used for indoor plastic floors, floor mats, car interior decorations, etc.

[0009] To achieve the above-mentioned purpose, the present invention provides a highly flame-retardant foaming modified styrene thermoplastic elastomer, which has the following characteristics: the raw materials for preparation include thermoplastic elastomer, polyolefin, solvent oil, macromolecular flame retardant, foaming agent, foaming promoter and crosslinking agent; the macromolecular flame retardant is polyphosphinosilazane; the solvent oil includes cyclopentane oil and epoxy soybean oil; the foaming agent is modified by epoxy soybean oil to obtain epoxy soybean oil modified foaming agent; the epoxy soybean oil modified foaming agent is then reacted with thermoplastic elastomer, polyolefin, cyclopentane oil, polyphosphinosilazane, foaming promoter and crosslinking agent to obtain the highly flame-retardant foaming modified styrene thermoplastic elastomer.

[0010] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein the mass proportion of the preparation raw materials is: 50-80 parts of thermoplastic elastomer, 10-30 parts of polyolefin, 30-50 parts of solvent oil, 0.5-10 parts of macromolecular flame retardant, 1-5 parts of foaming agent, 1-5 parts of foaming promoter and 0.1-3 parts of cross-linking agent.

[0011] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene-based thermoplastic elastomer, which may also have the following characteristics: wherein the mass ratio of the naphthenic oil to the epoxidized soybean oil is 7-9:3-1.

[0012] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene-based thermoplastic elastomer, which may also have the following characteristics: wherein the thermoplastic elastomer is poly(styrene-ethylene-butadiene-styrene) (SEBS), selected from one or a combination of the grades YH-688, YH-612, YH-610, YH-604, YH-602, YH-601, YH-561, YH-506, YH-504, YH-503T, YH-502T, YH-501T, and YH-501.

[0013] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein the polyolefin is selected from one or a combination of two of polyethylene (PE) and polypropylene (PP); the polyethylene is selected from one or a combination of several of the grades 1C7A, 1F7B, 1I2A, LD605, LD163, LD104, LD150, LD165, LD100, 2420H, 2426H, 1810D, and BF410; the polypropylene is selected from one or a combination of several of the grades M1600, J801R, J340, J801, R200P, and HJ801R.

[0014] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein the polyphosphinosilazane is selected from one or a combination of the grades TP-901a, TP-901d, TP-9128, and TP-9017.

[0015] Furthermore, the present invention provides a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein the foaming agent is azodicarbonamide (AC); the foaming promoter is selected from one or a combination of zinc oxide, zinc octoate, zinc nitrate, and zinc stearate; and the cross-linking agent is selected from one or a combination of two of di-tert-butyl peroxyisopropylbenzene (BIPB) and triallyl isocyanurate (TAIC).

[0016] The present invention also provides a preparation method of the highly flame-retardant foaming modified styrene thermoplastic elastomer, which has the following characteristics: comprising the following steps: step 1, uniformly mixing epoxy soybean oil and a foaming agent, and reacting them at 45-85°C for 0.5-3h to obtain an epoxy soybean oil-modified foaming agent; step 2, adding a thermoplastic elastomer, polyolefin, cycloalkane oil, polyphosphinosilazane, a foaming promoter and a cross-linking agent to the epoxy soybean oil-modified foaming agent obtained in step 1, and continuing to mix uniformly; step 3, extruding the mixture obtained in step 2 to form, the extrusion temperature is 170-190°C, and then performing compression foaming, the compression foaming temperature is 180°C, and the compression foaming time is 15-45min, to obtain a highly flame-retardant foaming modified styrene thermoplastic elastomer.

[0017] Furthermore, the present invention provides a method for preparing a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein, in step one, the epoxy soybean oil and the foaming agent are mixed by mechanical stirring at a stirring speed of 80-120 r / min.

[0018] Furthermore, the present invention provides a method for preparing a highly flame-retardant foamed modified styrene thermoplastic elastomer, which may also have the following characteristics: wherein, in step 2, the materials are mixed by using a high-speed mixer; in step 3, the mixture is extruded and formed by using a twin-screw extruder, and the compression foaming is performed by using a flat vulcanizer.

[0019] The highly flame-retardant foamed modified styrene thermoplastic elastomer provided by the present invention can improve the deficiencies of existing SEBS materials in terms of impact strength, rebound deformation and flame-retardant performance. Specifically, on the one hand, the present invention uses cycloalkane oil and epoxy soybean oil as dispersants, and the epoxy soybean oil molecular chain has both polar groups and non-polar segments. The epoxy groups in the epoxy soybean oil react with -NH2 in the AC foaming agent molecules to form covalent bonds, thereby reducing the polarity of the AC molecules, so that the AC molecules are grafted into the epoxy soybean oil from the original solid particles in the form of molecules, thereby improving the dispersion uniformity, fluidity and processing performance of the AC, and facilitating the regulation of subsequent foaming reactions, pore size and impact energy absorption effects; on the other hand, SEBS is used as the main material, and a macromolecular flame retardant polyphosphinosilazane is added to form an interpenetrating network structure with the matrix, and the double bonds in the flame retardant molecular chain react chemically with the double bonds in the SEBS molecular chain, thereby improving the compatibility of the flame retardant with the matrix and increasing the crosslinking degree of the matrix, thereby ultimately achieving the improvement of the tensile strength, impact strength and resilience of SEBS while giving it higher flame retardant properties.

[0020] The beneficial effects of the present invention are:

[0021] 1. No solvent is used in the preparation process, no halogen, no antimony compound, and it has the advantages of being environmentally friendly, non-toxic, and free of solvent residue.

[0022] 2. The raw material is mainly SEBS, which has both the high-temperature plasticity of resin and the low-temperature high elasticity of rubber, and the preparation process is simple to operate.

[0023] Third, the functional groups (C=C) in the macromolecular flame retardant are fully utilized to chemically react with the matrix molecular chain to form covalent bonds, thereby improving the compatibility of the flame retardant with the matrix material while improving the mechanical properties and flame retardant properties of the material.

[0024] 4. The micro-cross-linking reaction in the material preparation process improves the problems of linear SEBS molecular chains that are prone to plastic deformation due to linear slip when subjected to external loads, as well as poor impact resistance and wear resistance. At the same time, it reduces the permanent compression deformation of the material and significantly improves its rebound performance.

[0025] 5. At high temperatures, the silicon in the flame retardant molecules reacts with oxygen to form silicon oxides, increasing thermal stability. Nitrogen provides a gas source to promote the expansion and foaming of the system. Phosphorus provides an acid source (dehydrating agent) to react with the matrix to promote the formation of a carbonized layer and significantly increase its residual carbon rate. The resulting material has good flame retardancy, heat resistance, and aging resistance.

[0026] 6. In the present invention, the use of thermoplastic polyethylene (PE) or polypropylene (PP) to modify SEBS can reduce the melt viscosity of SEBS, improve the processing performance of SEBS, and at the same time, can also effectively improve the mechanical properties of SEBS elastomer; in addition, PE and PP are inexpensive, which can reduce the cost of SEBS elastomer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the reaction mechanism between a macromolecular flame retardant (brand number TP-9128) and a SEBS matrix in the preparation of the highly flame-retardant foamed modified styrene thermoplastic elastomer of the present invention;

[0028] Figure 2 1 is a stress-strain curve diagram of the thermoplastic elastomer prepared in each embodiment and comparative example 1;

[0029] Figure 3 are SEM images of the thermoplastic elastomers prepared in Example 3(b) and Comparative Example 1(a). DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0031] Example 1

[0032] This embodiment provides a highly flame retardant foamed modified styrene-based thermoplastic elastomer, and the preparation method thereof comprises the following steps:

[0033] Step 1: Weigh 3 parts of epoxidized soybean oil and 1 part of AC foaming agent, mix them evenly under mechanical stirring conditions, control the stirring speed to 80r / min, the reaction temperature to 60°C, and the reaction time to 0.5h to obtain epoxidized soybean oil modified AC foaming agent.

[0034] Step 2: Weigh 50 parts of SEBS, 20 parts of PE, 27 parts of cyclohexane oil, 0.5 parts of macromolecular flame retardant polyphosphinosilazane TP-9128 (purchased from Kube Chemical (Shanghai) Co., Ltd.), 1 part of foaming promoter zinc oxide, 0.05 parts of crosslinking agent BIPB, add the epoxy soybean oil modified AC foaming agent obtained in step 1, and continue to mix the above materials evenly using a high-speed mixer.

[0035] Step 3, add the mixture obtained in step 2 into a twin-screw extruder, set the rotor speed of the twin-screw extruder to 80r / min, and set the temperature of each zone to 170-190°C. Extrude, tug, cool, and wind the strips through the twin-screw extruder to obtain a strip. Weigh 150g of the strips and put them into a flat plate vulcanizer mold, put the mold into an electric heating flat plate vulcanizer at 180°C, close the mold and preheat for 30s, exhaust 3 times, and mold for 15min at a pressure of 5MPa, then open the mold and take out the sheet to obtain the product.

[0036] Example 2

[0037] This embodiment provides a highly flame retardant foamed modified styrene-based thermoplastic elastomer, and the preparation method thereof comprises the following steps:

[0038] Step 1: Weigh 6 parts of epoxidized soybean oil and 1 part of AC foaming agent, mix them evenly under mechanical stirring conditions, control the stirring speed to 100 r / min, the reaction temperature to 70° C., and the reaction time to 1 h to obtain an epoxidized soybean oil-modified AC foaming agent.

[0039] Step 2: weigh 50 parts of SEBS, 20 parts of PP, 24 parts of cyclohexane oil, 1 part of macromolecular flame retardant polyphosphinosilazane TP-9128, 1 part of foaming promoter zinc octoate, and 1 part of crosslinking agent BIPB, add the epoxy soybean oil modified AC foaming agent obtained in step 1, and continue to mix the above materials evenly using a high-speed mixer.

[0040] Step 3: Add the mixture obtained in step 2 into a twin-screw extruder, and set the rotor speed of the twin-screw extruder to 100 r / min. -1 , the temperature of each zone is set to 170-190℃. Extrusion, traction, cooling, winding and collection by twin-screw extruder to obtain strips. Weigh 150g of the strips and put them into the mold of the flat plate vulcanizer. Put the mold into the electric heating flat plate vulcanizer at 180℃, close the mold and preheat for 30s, exhaust 3 times, and mold for 30min at a pressure of 5MPa. Then open the mold and take out the sheet to obtain the product.

[0041] Example 3

[0042] This embodiment provides a highly flame retardant foamed modified styrene-based thermoplastic elastomer, and the preparation method thereof comprises the following steps:

[0043] Step 1: Weigh 9 parts of epoxidized soybean oil and 1.5 parts of AC foaming agent, mix them evenly under mechanical stirring conditions, control the stirring speed to 100 r / min, the reaction temperature to 70° C., and the reaction time to 1.5 h to obtain an epoxidized soybean oil-modified AC foaming agent.

[0044] Step 2: weigh 60 parts of SEBS, 10 parts of PE, 21 parts of cyclohexane oil, 2 parts of macromolecular flame retardant polyphosphinosilazane TP-9128, 1.5 parts of foaming promoter zinc stearate, and 0.2 parts of crosslinking agent BIPB, add the epoxy soybean oil modified AC foaming agent obtained in step 1, and continue to mix the above materials evenly using a high-speed mixer.

[0045] Step 3, add the mixture obtained in step 2 into a twin-screw extruder, set the rotor speed of the twin-screw extruder to 120r / min, and set the temperature of each zone to 170-190°C. Extrude, tug, cool, and wind the strips through the twin-screw extruder to obtain a strip. Weigh 150g of the strips and put them into a flat plate vulcanizer mold, put the mold into an electric heating flat plate vulcanizer at 180°C, close the mold and preheat for 30s, exhaust 3 times, and mold for 20min at a pressure of 10MPa, then open the mold and take out the sheet to obtain the product.

[0046] Example 4

[0047] This embodiment provides a highly flame retardant foamed modified styrene-based thermoplastic elastomer, and the preparation method thereof comprises the following steps:

[0048] Step 1: Weigh 6 parts of epoxidized soybean oil and 3 parts of AC foaming agent, mix them evenly under mechanical stirring conditions, control the stirring speed to 110r / min, the reaction temperature to 70°C, and the reaction time to 2h to obtain epoxidized soybean oil modified AC foaming agent.

[0049] Step 2: weigh 60 parts of SEBS, 10 parts of PE, 24 parts of cyclohexane oil, 3 parts of macromolecular flame retardant polyphosphinosilazane TP-9128, 3 parts of foaming promoter zinc nitrate, and 0.1 parts of crosslinking agent TAIC, add the epoxy soybean oil modified AC foaming agent obtained in step 1, and continue to mix the above materials evenly using a high-speed mixer.

[0050] Step 3, add the mixture obtained in step 2 into a twin-screw extruder, set the rotor speed of the twin-screw extruder to 120r / min, and set the temperature of each zone to 170-190°C. Extrude, tug, cool, and wind the strips through the twin-screw extruder to obtain a strip. Weigh 150g of the strips and put them into a flat plate vulcanizer mold, put the mold into an electric heating flat plate vulcanizer at 180°C, close the mold and preheat for 30s, exhaust 3 times, and mold for 45min at a pressure of 10MPa, then open the mold and take out the sheet to obtain the product.

[0051] Example 5

[0052] This embodiment provides a highly flame retardant foamed modified styrene-based thermoplastic elastomer, and the preparation method thereof comprises the following steps:

[0053] Step 1: Weigh 9 parts of epoxidized soybean oil and 5 parts of AC foaming agent, mix them evenly under mechanical stirring conditions, control the stirring speed to 120r / min, the reaction temperature to 80°C, and the reaction time to 2h to obtain epoxidized soybean oil modified AC foaming agent.

[0054] Step 2: weigh 60 parts of SEBS, 10 parts of PP, 21 parts of cyclohexane oil, 5 parts of macromolecular flame retardant polyphosphinosilazane TP-9128, 5 parts of foaming promoter zinc stearate, and 0.2 parts of crosslinking agent TAIC, add the epoxy soybean oil modified AC foaming agent obtained in step 1, and continue to mix the above materials evenly using a high-speed mixer.

[0055] Step 3, add the mixture obtained in step 2 into a twin-screw extruder, set the rotor speed of the twin-screw extruder to 120r / min, and set the temperature of each zone to 170-190°C. Extrude, tug, cool, and wind the strips through the twin-screw extruder to obtain a strip. Weigh 150g of the strips and put them into a flat plate vulcanizer mold, put the mold into an electric heating flat plate vulcanizer at 180°C, close the mold and preheat for 30s, exhaust 3 times, and mold for 30min at a pressure of 10MPa, then open the mold and take out the sheet to obtain the product.

[0056] Comparative Example 1

[0057] This comparative example provides a foam-modified styrene-based thermoplastic elastomer, and its preparation method comprises the following steps:

[0058] Step 1: Weigh 50 parts of SEBS, 20 parts of PP, 30 parts of cyclohexane oil, 1 part of AC foaming agent, 1 part of foaming promoter zinc oxide and 0.1 part of crosslinking agent BIPB, and mix the above materials evenly using a high-speed mixer.

[0059] Step 2: Add the mixture obtained in step 1 to a twin-screw extruder, set the rotor speed of the twin-screw extruder to 100r / min, and set the temperature of each zone to 170-190°C. Extrude, tug, cool, and wind the strips through the twin-screw extruder to obtain a strip. Weigh 150g of the strips and put them into a flat plate vulcanizer mold. Put the mold into an electric heating flat plate vulcanizer at 180°C, close the mold and preheat for 30s, exhaust 3 times, and mold for 30min at a pressure of 5MPa. Then, open the mold and take out the sheet to obtain the product.

[0060] The products prepared in each embodiment and comparative example 1 were subjected to performance tests, including (1) tensile strength test: measured with reference to GB / T 528-2009 Test method for tensile stress-strain properties of vulcanized rubber or thermoplastic rubber; (2) impact absorption and vertical deformation test: according to BS EN14808-2005 Determination of shock absorption of sports ground and BS EN14809-2005 Determination of vertical deformation of sports ground, this experiment was tested using an impact absorption and vertical deformation tester; (3) rebound performance test: according to GB / T 1681-2009 Determination of rebound elasticity of vulcanized rubber, this experiment used a KRT elastic machine to test the rebound performance of elastomeric materials; (4) flame retardant performance analysis: the sample was placed vertically, a 20 mm long flame was moved to the bottom of the sample, the contact length between the flame and the sample was 10 mm, the flame was removed after 10 seconds, and the time from the removal of the flame to the extinguishing of the flame on the sample was recorded, according to GB / T 2406.2-2009 tested the oxygen index of the sample and evaluated its flame retardant performance. The test results are shown in Table 1.

[0061] Table 1 Performance comparison of highly flame retardant foamed modified SEBS and foamed modified SEBS

[0062]

[0063] As can be seen from Table 1, the tensile strength, impact absorption, rebound rate, vertical deformation and oxygen index of the highly flame-retardant foamed modified SEBS prepared in Examples 1-5 are higher than those of the foamed modified SEBS in Comparative Example 1, while the self-extinguishing time after fire is lower than that of Comparative Example 1. This indicates that the mechanical properties and flame retardant properties of the highly flame-retardant foamed modified SEBS prepared by the method of the present invention are better than those of Comparative Example 1.

[0064] The stress-strain curves of the samples obtained in each embodiment and comparative example 1 are as follows: Figure 2 As shown, from Figure 2 It can be seen that the mechanical properties of the highly flame retardant foamed modified SEBS prepared by the method of the present invention are better than those of Comparative Example 1. The SEM images of the samples prepared in Example 3 and Comparative Example 1 are as follows: Figure 3 shown.

[0065] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly flame-retardant foamed modified styrene thermoplastic elastomer, characterized in that: The preparation raw materials include thermoplastic elastomer, polyolefin, solvent oil, macromolecular flame retardant, foaming agent, foaming promoter and crosslinking agent; the mass proportion is: 50-80 parts of thermoplastic elastomer, 10-30 parts of polyolefin, 30-50 parts of solvent oil, 0.5-10 parts of macromolecular flame retardant, 1-5 parts of foaming agent, 1-5 parts of foaming promoter and 0.1-3 parts of crosslinking agent; The macromolecular flame retardant is polyphosphinosilazane; the polyphosphinosilazane is selected from one or a combination of the grades TP-901a, TP-901d, TP-9128, and TP-9017; The solvent oil includes naphthenic oil and epoxidized soybean oil; the mass ratio of naphthenic oil to epoxidized soybean oil is 7-9:3-1; The thermoplastic elastomer is poly(styrene-ethylene-butadiene-styrene); The polyolefin is selected from one or a combination of polyethylene and polypropylene; The foaming agent is azodicarbonamide; The cross-linking agent is selected from one or a combination of di-tert-butyl peroxyisopropylbenzene and triallyl isocyanurate; The epoxy soybean oil is used to modify the foaming agent to obtain the epoxy soybean oil modified foaming agent; the preparation method of the epoxy soybean oil modified foaming agent is as follows: the epoxy soybean oil and the foaming agent are mixed evenly, and reacted at 45-85°C for 0.5-3 h to obtain the epoxy soybean oil modified foaming agent; the epoxy soybean oil modified foaming agent is then reacted with a thermoplastic elastomer, a polyolefin, cycloalkane oil, polyphosphinosilazane, a foaming promoter and a crosslinking agent to obtain the highly flame-retardant foaming modified styrene thermoplastic elastomer.

2. The highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to claim 1, characterized in that: in, The poly(styrene-ethylene-butadiene-styrene) is selected from one or a combination of the grades YH-688, YH-612, YH-610, YH-604, YH-602, YH-601, YH-561, YH-506, YH-504, YH-503T, YH-502T, YH-501T, and YH-501.

3. The highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to claim 1, characterized in that: in, The polyethylene is selected from one or a combination of 1C7A, 1F7B, 1I2A, LD605, LD163, LD104, LD150, LD165, LD100, 2420H, 2426H, 1810D, and BF410; The polypropylene is selected from one or a combination of the grades M1600, J801R, J340, J801, R200P, and HJ801R.

4. The highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to claim 1, characterized in that: in, The foaming promoter is selected from zinc oxide, zinc octoate, zinc nitrate, zinc stearate or a combination thereof.

5. The method for preparing a highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, mixing the epoxy soybean oil and the foaming agent evenly, and reacting at 45-85° C. for 0.5-3 h to obtain the epoxy soybean oil modified foaming agent; Step 2: adding the thermoplastic elastomer, polyolefin, cyclohexane oil, polyphosphinosilazane, foaming promoter and crosslinking agent to the epoxy soybean oil modified foaming agent obtained in step 1, and continue to mix evenly; Step 3: Extruding the mixture obtained in step 2 to form a product at an extrusion temperature of 170-190°C, and then performing compression foaming at a compression foaming temperature of 180°C for a compression foaming time of 15-45 min to obtain a highly flame retardant foamed modified styrene thermoplastic elastomer.

6. The highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to claim 5, characterized in that: in, In step 1, the epoxy soybean oil and the foaming agent are mixed by mechanical stirring at a stirring speed of 80-120 r / min.

7. The highly flame-retardant foamed modified styrene-based thermoplastic elastomer according to claim 5, characterized in that: in, In step 2, the materials are mixed by using a high-speed mixer; In step three, the mixture is extruded and formed by using a twin-screw extruder, and the foaming is performed by using a flat vulcanizing machine.

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