High flame retardant thermoplastic elastomer

Abstract

This invention discloses a high flame-retardant thermoplastic elastomer, comprising the following raw materials in parts by weight: 50-75 parts of thermoplastic polyurethane elastomer, 10-18 parts of paraffin oil, 11.5-13.5 parts of polyester flame retardant, 10-15 parts of polyethylene resin, 7-13 parts of styrene resin, and 0.1-0.8 parts of antioxidant. The preparation method is as follows: the thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin, and antioxidant are dried in a drying oven at 50-55°C for 15-20 hours, then added to an RM-200C type mixing torque rheometer. After mixing, the high flame-retardant thermoplastic elastomer is obtained, with a UL94 rating of V-0, exhibiting excellent flame-retardant properties. Furthermore, the tensile strength and elongation at break are not affected, making it a good environmentally friendly flame-retardant material.

Description

Technical Field

[0001] This invention relates to the field of new materials technology, specifically to a highly flame-retardant thermoplastic elastomer. Background Technology

[0002] Thermoplastic elastomers (TPE / TPR), also known as synthetic rubber or artificial rubber, possess the excellent properties of traditional cross-linked vulcanized rubber, including high elasticity, aging resistance, and oil resistance, while also offering the ease of processing and wide range of processing methods available for ordinary plastics. They can be produced using injection molding, extrusion, blow molding, and other processing methods, and the sprue scraps can be 100% directly reused after being crushed. This simplifies the processing process and reduces costs, making TPE / TPR materials the latest material to replace traditional rubber. Their environmental friendliness, non-toxicity, comfortable feel, and attractive appearance allow for more creative product designs. Therefore, they are a more human-centered, high-quality new synthetic material and a globally standardized environmentally friendly material.

[0003] Thermoplastic polyurethane elastomers are block linear polymers whose main chain contains repeating urethane groups. They can be plasticized by heating and dissolved in solvents. They possess both the high strength and hardness of plastics and the elasticity of rubber. Thermoplastic polyurethane elastomers are characterized by excellent abrasion resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low-temperature resistance, and good resistance to oil, chemicals, and environmental factors. They are widely used in defense, medical, and food industries. However, thermoplastic polyurethane elastomers are highly flammable and have poor char-forming ability, producing little or no char residue after combustion. They cannot form a protective char layer, thus failing to effectively prevent further combustion of the matrix. As the application volume and fields of thermoplastic polyurethane elastomers expand, various industries are demanding higher fire safety levels. Therefore, it is essential to adopt scientific and effective methods to improve the fire safety of thermoplastic polyurethane elastomer materials.

[0004] To address the flammability of thermoplastic polyurethane elastics, flame retardants are often added to improve their flame retardancy. Currently, the amount of flame retardant added is around 20%. Among them, phosphorus-based flame retardants are widely used in thermoplastic polyurethane elastics due to their high flame retardancy efficiency and environmental friendliness. However, excessive addition of flame retardants can lead to a decrease in the physical and mechanical properties of thermoplastic polyurethane elastics. Furthermore, existing flame retardants also have the problem of easy precipitation. Therefore, this invention develops a polyester-type flame retardant to solve the problem of easy precipitation of small molecule flame retardants, thereby improving the flame retardancy of thermoplastic polyurethane elastics without affecting their physical and mechanical properties. Summary of the Invention

[0005] The purpose of this invention is to provide a highly flame-retardant thermoplastic elastomer.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 50-75 parts of thermoplastic polyurethane elastomer, 10-18 parts of paraffin oil, 11.5-13.5 parts of polyester flame retardant, 10-15 parts of polyethylene resin, 7-13 parts of styrene resin, and 0.1-0.8 parts of antioxidant.

[0008] Furthermore, the anti-aging agent is a phosphite antioxidant, specifically a cyclic pentapentaerythritol di(2,6-di-tert-butyl-4-methylphenyl phosphite) or pentaerythritol diisodecyl phosphite.

[0009] Furthermore, the preparation method of the polyester-type flame retardant is as follows:

[0010] Step 1: Add 2.0-2.5g phenylphosphonic dichloride, 5-7g base catalyst and 80-100ml toluene solvent to a flask, heat to 60-65℃ while stirring, then add 2.3-3.0g glycine, continue heating to 80-90℃, maintain the temperature for 40-60min, after the reaction is complete, cool naturally to room temperature, filter, remove solvent by vacuum distillation, then wash 2-3 times with 100ml purified water, and dry to obtain the intermediate compound;

[0011] Step 2: Add 2.8-3.2g of intermediate compound, 1.5-1.7g of 3,4-pyridine dibenzyl alcohol, and 20-25mg of polyester reaction catalyst to a high-pressure reactor. Purge with nitrogen for 2-3 minutes and carry out esterification reaction at a pressure of 0.1-0.3MPa and a temperature of 190-195℃. Remove water while reacting. After reacting for 1.5-2 hours, raise the temperature to 215-225℃ for polycondensation reaction for 35-45 minutes. After the reaction is completed, wash with 50ml of anhydrous ethanol 3-5 times to obtain polyester flame retardant.

[0012] Furthermore, in the first step, the alkaline catalyst is cesium carbonate.

[0013] Furthermore, in the second step, the polyester reaction catalyst is tetraisopropyl titanate.

[0014] Furthermore, the preparation method of the high flame retardant thermoplastic elastomer is as follows: after drying thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent in a drying oven at 50-55℃ for 15-20h, they are added to an RM-200C type mixing torque rheometer, and after mixing, the high flame retardant thermoplastic elastomer is obtained.

[0015] Furthermore, the RM-200C mixing torque rheometer is set to a speed of 65-75 rpm, a device temperature from the hopper to the mold of 190-195℃, and a mixing time of 10-15 min.

[0016] The beneficial effects of this invention are:

[0017] This invention provides a highly flame-retardant thermoplastic elastomer with a UL94 rating of V-0, exhibiting excellent flame-retardant properties. Furthermore, its tensile strength and elongation at break are not affected. The amount of flame retardant added is less than 15% of the total raw material. The prepared polyester flame retardant contains flame-retardant nitrogen (N) and phosphorus (P) elements. During combustion, the nitrogen element can generate nitric oxide or nitrogen dioxide gas, which can assist the phosphorus element in blocking oxygen, thus jointly exerting flame-retardant efficacy. In addition, the polyester flame retardant contains a large number of benzene rings and pyridine ring structures, giving the elastomer good thermal stability and delaying combustion.

[0018] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a reaction flow diagram of the polyester flame retardant of the present invention;

[0021] Figure 2 This is the NMR spectrum of the polyester flame retardant of the present invention;

[0022] Figure 3 The infrared spectrum of the polyester flame retardant of this invention is shown. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following embodiments, such as Figure 1 As shown, the preparation method of polyester flame retardant is as follows:

[0025] Step 1: Add 2.5g phenylphosphonic dichloride, 6.0g cesium carbonate as a base catalyst, and 100ml toluene as solvent to a flask. Heat to 60℃ while stirring, then add 2.5g glycine and continue heating to 80℃. Maintain the temperature for 50min. After the reaction, allow to cool naturally to room temperature, filter, remove the solvent by vacuum distillation, and then wash three times with 100ml purified water. After drying, the intermediate compound is obtained with a yield of 74.4%. Weigh 1mg and dissolve it in 1ml acetonitrile solution, dilute to 10ml, and inject 1µl into the mass spectrometer. Figure 2 The results obtained as shown are MS(C). 10 H 13 O5N2P): m / z = 272.0619;

[0026] Step 2: Add 3.0g of intermediate compound, 1.6g of 3,4-pyridine dibenzyl alcohol, and 25mg of tetraisopropyl titanate, a polyester reaction catalyst, to a high-pressure reactor. Purge with nitrogen for 3 minutes, and carry out an esterification reaction at 190℃ under a pressure of 0.25MPa, removing water simultaneously. After 2 hours of reaction, raise the temperature to 220℃ for a polycondensation reaction for 40 minutes. After the reaction, wash four times with 50ml of anhydrous ethanol to obtain the polyester-type flame retardant. Analyze the sample using the KBr tableting method and infrared spectroscopy. Figure 3 As shown, 1280cm -1 The point is the stretching vibration of the phosphorus-oxygen bond, 1734 cm⁻¹ -1 The point is the stretching vibration of the carbon-oxygen bond, 3483 cm⁻¹. -1 The vibration at this point is the stretching vibration of amino hydrogen.

[0027] Example 1

[0028] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 55g thermoplastic polyurethane elastomer, 13g paraffin oil, 12g polyester flame retardant, 13g polyethylene resin, 10g styrene resin, and 0.3g cyclic pentapentapentanetetramethyldi(2,6-di-tert-butyl-4-methylphenyl phosphite) anti-aging agent.

[0029] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 50℃ for 17h, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 65rpm, a device temperature of 190℃ from the hopper to the mold, and a mixing time of 12min. After mixing, the high flame retardant thermoplastic elastomer is obtained.

[0030] Example 2

[0031] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 64g of thermoplastic polyurethane elastomer, 10g of paraffin oil, 11.5g of polyester flame retardant, 11.5g of polyethylene resin, 13g of styrene resin, and 0.4g of anti-aging agent pentaerythritol diisodecyl phosphate.

[0032] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 55℃ for 20h, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 75rpm, a device temperature of 195℃ from the hopper to the mold, and a mixing time of 10min. After mixing, the high flame retardant thermoplastic elastomer is obtained.

[0033] Example 3

[0034] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 65g of thermoplastic polyurethane elastomer, 15g of paraffin oil, 13.5g of polyester flame retardant, 12g of polyethylene resin, 7g of styrene resin, and 0.5g of anti-aging agent pentaerythritol diisodecyl phosphate.

[0035] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 50℃ for 16 hours, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 70 rpm, a device temperature of 195℃ from the hopper to the mold, and a mixing time of 10 minutes. After mixing, high flame retardant thermoplastic elastomer is obtained.

[0036] Example 4

[0037] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 70g of thermoplastic polyurethane elastomer, 17g of paraffin oil, 13g of polyester flame retardant, 14g of polyethylene resin, 8g of styrene resin, and 0.2g of cyclic pentapentapentanetetramethyldi(2,6-di-tert-butyl-4-methylphenylphosphite) anti-aging agent.

[0038] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 55℃ for 15 hours, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 65 rpm, a temperature of 192℃ from the hopper to the mold, and a mixing time of 15 minutes. After mixing, the high flame retardant thermoplastic elastomer is obtained.

[0039] Comparative Example 1

[0040] The amount of polyester flame retardant added was increased to 27g (accounting for approximately 20% of the total weight of the elastomer), and the rest was the same as in Example 4;

[0041] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 70g thermoplastic polyurethane elastomer, 17g paraffin oil, 27g polyester flame retardant, 14g polyethylene resin, 8g styrene resin, and 0.2g cyclic pentapentapentanetetramethyldi(2,6-di-tert-butyl-4-methylphenyl phosphite) anti-aging agent.

[0042] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 55℃ for 15 hours, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 65 rpm, a temperature of 192℃ from the hopper to the mold, and a mixing time of 15 minutes. After mixing, the high flame retardant thermoplastic elastomer is obtained.

[0043] Comparative Example 2

[0044] Flame retardants are prepared using intermediate compounds. The rest is the same as in Example 4;

[0045] A highly flame-retardant thermoplastic elastomer comprises the following raw materials in parts by weight: 70g thermoplastic polyurethane elastomer, 17g paraffin oil, 13g intermediate compound, 14g polyethylene resin, 8g styrene resin, and 0.2g antioxidant cyclic pentapentapentanetetramethyldi(2,6-di-tert-butyl-4-methylphenylphosphite).

[0046] The preparation method of high flame retardant thermoplastic elastomer is as follows: thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent are dried in a drying oven at 55℃ for 15 hours, and then added to an RM-200C type mixing torque rheometer with a rotation speed of 65 rpm, a temperature of 192℃ from the hopper to the mold, and a mixing time of 15 minutes. After mixing, the high flame retardant thermoplastic elastomer is obtained.

[0047] The flame retardant and mechanical properties of the prepared high flame retardant thermoplastic elastomer were tested.

[0048]

[0049]

[0050] As shown in the table above, the UL94 rating of the high flame-retardant thermoplastic elastomers prepared in Examples 1-4 is V-0, indicating excellent flame-retardant properties. In addition, the tensile strength and elongation at break properties are not affected. This may be because the added polyester-type flame retardant has good compatibility with the components, while the intermediate compound in Comparative Example 2 is prone to precipitation and has poor compatibility with macromolecular thermoplastic polyurethane elastomers, polyethylene resins, and styrene resins, resulting in poor flame-retardant and mechanical properties.

[0051] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A highly flame-retardant thermoplastic elastomer, characterized in that, The raw materials include the following parts by weight: 50-75 parts thermoplastic polyurethane elastomer, 10-18 parts paraffin oil, 11.5-13.5 parts polyester flame retardant, 10-15 parts polyethylene resin, 7-13 parts styrene resin, and 0.1-0.8 parts anti-aging agent. The preparation method of the polyester-type flame retardant is as follows: Step 1: Add 2.0-2.5g phenylphosphonic dichloride, 5-7g base catalyst and 80-100ml toluene solvent to a flask, heat to 60-65℃ while stirring, then add 2.3-3.0g glycine, continue heating to 80-90℃, maintain the temperature for 40-60min, after the reaction is complete, cool naturally to room temperature, filter, remove solvent by vacuum distillation, then wash 2-3 times with 100ml purified water, and dry to obtain the intermediate compound; Step 2: Add 2.8-3.2g of intermediate compound, 1.5-1.7g of 3,4-pyridine dibenzyl alcohol, and 20-25mg of polyester reaction catalyst to a high-pressure reactor. Purge with nitrogen for 2-3 minutes and carry out esterification reaction at a pressure of 0.1-0.3MPa and a temperature of 190-195℃. Remove water while reacting. After reacting for 1.5-2 hours, raise the temperature to 215-225℃ for polycondensation reaction for 35-45 minutes. After the reaction is completed, wash with 50ml of anhydrous ethanol 3-5 times to obtain polyester flame retardant.

2. The high flame-retardant thermoplastic elastomer according to claim 1, characterized in that, The anti-aging agent is a phosphite antioxidant, specifically a cyclic pentapentaerythritol di(2,6-di-tert-butyl-4-methylphenyl phosphite) or pentaerythritol diisodecyl phosphate.

3. The high flame-retardant thermoplastic elastomer according to claim 1, characterized in that, In the first step, the alkaline catalyst is cesium carbonate.

4. The high flame-retardant thermoplastic elastomer according to claim 1, characterized in that, In the second step, the polyester reaction catalyst is tetraisopropyl titanate.

5. The high flame-retardant thermoplastic elastomer according to claim 1, characterized in that, The preparation method of high flame retardant thermoplastic elastomer is as follows: after drying thermoplastic polyurethane elastomer, paraffin oil, polyester flame retardant, polyethylene resin, styrene resin and anti-aging agent in a drying oven at 50-55℃ for 15-20h, they are added to an RM-200C type mixing torque rheometer, and after mixing, high flame retardant thermoplastic elastomer is obtained.

6. The highly flame-retardant thermoplastic elastomer according to claim 5, characterized in that, The RM-200C mixing torque rheometer is set to a speed of 65-75 rpm, a material temperature of 190-195℃ from the hopper to the mold, and a mixing time of 10-15 min.

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