A TPU material and preparation process

Abstract

The present invention discloses a TPU material and preparation process. The TPU material is prepared from the following raw materials in parts by weight: 80-120 parts TPU, 20-35 parts multifunctional additive, 0.2-2.5 parts antioxidant, and 0.2-2 parts thermal stabilizer. The preparation process provided by the present invention is relatively simple, comprising the following steps: weighing the raw material components in proportion, mixing them uniformly, and then feeding them into a twin-screw granulator for granulation. The present invention, through the preferred use of silica, attapulgite, and carbon nanotubes, and through modification, imparts excellent comprehensive properties to the TPU material.

Description

Technical Field

[0001] The present invention belongs to the technical field of new material preparation, and in particular relates to a TPU material and a preparation process. Background Art

[0002] TPU is a thermoplastic polyurethane material composed of two groups, soft and hard. This unique two-phase structure gives TPU excellent mechanical properties and chemical resistance. Due to its excellent elasticity, tensile strength, wear resistance, tear resistance and chemical resistance, TPU is widely used in the fields of automobiles, machinery, medical treatment, footwear, electronic appliances, etc., and is used to manufacture various wear-resistant and impact-resistant components and products. For example, in the production process of lithium batteries, when the robotic arm grabs the lithium battery materials, in order to avoid friction and collisions between the materials, TPU materials are often needed for isolation. Therefore, TPU materials are required to have certain antistatic and wear-resistant properties. In fact, in the use of other fields such as automobiles and footwear, flame retardancy is a performance indicator that cannot be ignored. Therefore, it is very necessary to prepare TPU materials with antistatic and flame retardancy.

[0003] In the prior art, patent document CN106751716A, for example, provides a transparent antistatic TPU film and its preparation method and application. The film is composed of TPU particles, epoxy resin, polycarbonate particles, K glue, carbon nanotubes, glass fiber, and antioxidant. By using the above substances, the various raw material components of the TPU film cooperate with each other and work synergistically, resulting in a transparency of 6-8mm, a tensile strength of 72-77MPa, and an elongation at break of 365-390%, achieving high transparency, good antistatic properties, and good mechanical properties. However, the above patents do not focus on the flame retardancy of the material. Similarly, CN106003948A and CN103834051A only focus on antistatic properties.

[0004] For example, patent document CN104861637A provides a mixing method for flame-retardant TPU cable materials, which consists of 100 parts of TPU raw material A, 6-12 parts of TCEP flame retardant B, 8-12 parts of DMMP flame retardant C, 5-10 parts of APP flame retardant D, and 5-10 parts of zinc borate flame retardant E. The cable material prepared based on the above raw materials has good flame retardant properties, but no attention is paid to antistatic properties.

[0005] For example, patent document CN114836023A provides a flame-retardant and antistatic TPU composite material. The raw materials used, by weight, are: 1-3 parts expandable graphene oxide, 3-6 parts ammonium polyphosphate, 5-8 parts triphenylboroxine, 85-90 parts TPU particles, and 90 parts DMF. Boron-based flame retardants and carbon materials are used as flame retardants, resulting in excellent flame retardancy. The triphenylboroxine has good dispersibility in the TPU material and synergistically acts with the expandable graphene oxide, resulting in excellent antistatic properties. However, it is noted that a large amount of DMF solvent is used, and the antistatic and flame retardant properties need to be further improved.

[0006] Therefore, the present invention has conducted relevant research around the improvement of the antistatic property and flame retardancy of TPU materials. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a TPU material and a preparation process. The prepared TPU material has good flame retardancy, good antistatic properties, good mechanical properties and excellent comprehensive performance.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a TPU material prepared from the following raw materials in parts by weight: 80 to 120 parts of TPU, 20 to 35 parts of a multifunctional additive, 0.2 to 2.5 parts of an antioxidant, and 0.2 to 2 parts of a heat stabilizer;

[0010] The preparation of the multi-functional additive comprises the following steps:

[0011] S11, pre-modification of attapulgite: the attapulgite is mixed evenly with sodium hydroxide and then subjected to high temperature treatment. After the treatment is completed, the mixture is crushed to obtain pre-modified attapulgite;

[0012] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid, heating and stirring, centrifuging and filtering, washing to neutrality, and drying to obtain secondary modified attapulgite, which is set aside;

[0013] S13, adding the carbon nanotubes to concentrated nitric acid for acidification, washing after the treatment, then adding to water, then adding KH550, treating under heating conditions, filtering, washing, and drying after the treatment to obtain modified carbon nanotubes;

[0014] S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a buffer solution containing dopamine, soaking them, and then centrifuging and filtering them to obtain a composite material;

[0015] S15, placing the silicon dioxide in the mixed solution for treatment, and washing it after the treatment is completed to obtain modified silicon dioxide for standby use;

[0016] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 into water and treat them under heating conditions. After the treatment, wash, dry and crush them to obtain a multi-functional additive.

[0017] Preferably, the antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168;

[0018] The heat stabilizer is selected from one or both of calcium stearate and zinc stearate.

[0019] Preferably, in step S11, the mass ratio of attapulgite to sodium hydroxide is 1:0.35-0.65; the high temperature treatment temperature is 780-805° C., and the treatment time is 0.5-4 h.

[0020] Preferably, in step S12, the concentration of boric acid in the ethanol solution is 0.04-0.08 g / mL; the mass ratio of boric acid to pre-modified attapulgite is 1:1.5-2.8; the heating and stirring treatment temperature is 60-75° C., and the treatment time is 5-10 min;

[0021] Preferably, in step S13, the ratio of carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g: 4-8 g: 0.5-0.8 mL: 12-20 mL; the concentration of concentrated nitric acid is 4-6.5 mol / L;

[0022] The acidification treatment temperature is 55-75°C and the treatment time is 0.5-4h;

[0023] The heating temperature is 65 to 85° C., and the processing time under the heating condition is 1 to 4 hours.

[0024] Preferably, in step S14, the dopamine-containing buffer solution is obtained by mixing Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1; the pH value of the dopamine-containing buffer solution is 7.8 to 8.5;

[0025] The ratio of secondary modified attapulgite, dopamine-containing buffer solution and modified carbon nanotubes is 1 g: 5-10 mL: 0.25-0.5;

[0026] The soaking treatment temperature is room temperature and the treatment time is 8 to 16 hours.

[0027] Preferably, in step S15, the mixed solution is obtained by mixing concentrated sulfuric acid and hydrogen peroxide solution in a volume ratio of 7:3; the amount ratio of silicon dioxide to the mixed solution is 1 g: 4-12 mL; the treatment temperature is room temperature, and the treatment time is 0.5-4 h.

[0028] Preferably, in step S16, the mass ratio of the composite material, modified silicon dioxide and water is 1:0.25-0.45:8-15; the heating temperature is 30-40° C., and the treatment time is 2-6 hours.

[0029] In a second aspect, the present invention provides a process for preparing the above-mentioned TPU material, comprising the following steps:

[0030] Weigh each raw material component in proportion and mix them evenly, then send them into a twin-screw granulator for granulation.

[0031] Preferably, the processing temperature of the twin-screw granulator is 160-175°C, and the screw speed is 120-200 rpm. It is understood that the above processing temperatures meet the actual requirements of TPU processing. The present invention does not impose strict restrictions on the temperature of each zone of the twin-screw granulator, and it can be adjusted by those skilled in the art.

[0032] It should be noted that after extrusion, the obtained masterbatch can be processed accordingly according to the needs of the application scenario to produce the desired TPU product. The present invention does not limit its application form and scenario.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The TPU material provided by the present invention has good antistatic and flame retardant effects and has good application value in the preparation of related materials in the electronics industry.

[0035] The present invention provides a TPU material, which, through the use of a multi-effect additive, gives the TPU material antistatic and flame retardancy. Specifically, the multi-effect flame retardant uses carbon nanotubes, which have a low surface charge density and excellent antistatic properties; attapulgite and silicon dioxide have good high-heat resistance, and can form a dense film structure when filled between TPU particles, effectively preventing the circulation of oxygen and achieving a flame retardant effect; however, the above particles still have some deficiencies when used. For example, although the carbon nanotubes have very good performance, they are very easy to agglomerate, thereby reducing the performance of use. Similarly, attapulgite and silicon dioxide have poor compatibility with TPU particles. Therefore, the present invention has some deficiencies when used. During the process, the above raw materials were modified to a certain extent. For example, the attapulgite was first subjected to a high-temperature alkali melting treatment, which, on the one hand, improved its activity and, on the other hand, enriched its pores, which was beneficial to the subsequent modification with boric acid and the deposition of dopamine. The attapulgite was then modified with boric acid, one purpose of which was to introduce boron elements to improve the flame retardant properties, and the other purpose was to improve the effect of subsequent dopamine deposition based on some hydroxyl groups introduced by the boric acid modification. Finally, the attapulgite was treated with dopamine. Dopamine has very rich hydroxyl and amino groups and has good compatibility with TPU particles. Its introduction on the surface of the attapulgite can greatly improve the dispersibility and compatibility of the attapulgite.

[0036] In this application, attapulgite and modified carbon nanotubes are treated together by optimizing the treatment conditions, thereby shortening the treatment process. The carbon nanotubes are first subjected to an acidification treatment, which is beneficial for introducing functional groups such as carboxyl and hydroxyl groups to improve their activity. KH550 is then introduced for treatment. The hydrolysis of KH550 forms hydroxyl groups that will form hydrogen bonds with the acidified carbon nanotubes on the one hand. On the other hand, the hydroxyl groups and amino groups contained in KH550 will also combine with the subsequent dopamine, which is beneficial for improving the deposition modification of dopamine.

[0037] In order to improve the dispersibility of silica in this application, a simple mixed acid treatment is performed on it to introduce hydroxyl groups, so as to form a large filling system based on hydrogen bonds and other forms of effects with dopamine-modified attapulgite and carbon nanotubes, densely filling, improving the film-forming effect, and maximizing the flame retardant and antistatic effects.

[0038] In summary, the present invention gives the TPU material excellent comprehensive properties (good mechanical properties) through the preferred use of silicon dioxide, attapulgite, and carbon nanotubes and modification. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below. All embodiments are exemplary and intended to be used to explain the present invention, but are not to be construed as limiting the present invention.

[0040] Unless otherwise specified, the chemical reagents and production equipment involved in the present invention were purchased from the market.

[0041] Among them, attapulgite was purchased from Changzhou Naou New Material Technology Co., Ltd.

[0042] Silica was nano-silica purchased from Shanghai Huijing Nano New Materials Co., Ltd.;

[0043] Carbon nanotubes were purchased from Jiaxing Naco New Materials Co., Ltd. with a length of 10 μm and a diameter of about 50 nm.

[0044] TPU was purchased from Yantai Wanhua with the brand name WHT-1565IC.

[0045] The concentration of concentrated sulfuric acid is 98 wt % and the concentration of hydrogen peroxide is 30 wt %.

[0046] Example 1

[0047] A TPU material is prepared from the following raw materials by weight: 100g TPU, 30g multi-functional additive, 1.5g antioxidant 1010, and 2g zinc stearate.

[0048] The preparation of the multi-functional additive comprises the following steps:

[0049] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.45 and then subjected to high temperature treatment (790°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0050] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid (0.05 g / mL) at a mass ratio of 2.5:1, heating and stirring (65°C, 8 min), centrifuging and filtering, washing to neutrality, and drying to obtain a secondary modified attapulgite, which is set aside;

[0051] S13, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (60°C, 0.5 h), washing the mixture after the treatment, then adding the mixture to water, and then adding KH550, treating the mixture under heating conditions (75°C, 1 h). After the treatment, filtering, washing, and drying the mixture to obtain modified carbon nanotubes; wherein the amount ratio of the carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g:5 g:0.55 mL:15 mL;

[0052] S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a dopamine-containing buffer solution (Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1, pH 8), soaking them (at room temperature for 12 hours), and then centrifuging and filtering them to obtain a composite material; wherein the amount ratio of the secondary modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g:8 mL:0.35;

[0053] S15. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a dosage ratio of 1:6 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0054] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, and treat them under heating conditions (35°C, 4h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.3:10.

[0055] In this embodiment, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0056] Example 2

[0057] A TPU material is prepared from the following raw materials by weight: 100g TPU, 28g multi-functional additive, 1.8g antioxidant 1010, and 1.8g zinc stearate.

[0058] The preparation of the multi-functional additive comprises the following steps:

[0059] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.5 and then subjected to high temperature treatment (795°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0060] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid (0.04 g / mL) at a mass ratio of 2.5:1, heating and stirring (60°C, 10 min), centrifuging and filtering, washing to neutrality, and drying to obtain a secondary modified attapulgite, which is set aside;

[0061] S13, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (65°C, 0.5 h), washing the mixture after the treatment, then adding the mixture to water, and then adding KH550, treating the mixture under heating conditions (75°C, 1 h). After the treatment, filtering, washing, and drying the mixture to obtain modified carbon nanotubes; wherein the amount ratio of the carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g:4.5 g:0.58 mL:12 mL;

[0062] S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a dopamine-containing buffer solution (Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1, pH 8), soaking them (at room temperature for 12 hours), and then centrifuging and filtering them to obtain a composite material; wherein the ratio of the secondary modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g:8 mL:0.38;

[0063] S15. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a ratio of 1:7 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0064] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, and treat them under heating conditions (35°C, 3.5h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.28:10.

[0065] In this embodiment, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0066] Example 3

[0067] A TPU material is prepared from the following raw materials by weight: 100g TPU, 28g multi-functional additive, 2.2g antioxidant 1010, and 1.9g zinc stearate.

[0068] The preparation of the multi-functional additive comprises the following steps:

[0069] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.5 and then subjected to high temperature treatment (795°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0070] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid (0.06 g / mL) at a mass ratio of 2.3:1, heating and stirring (60°C, 10 min), centrifuging and filtering, washing to neutrality, and drying to obtain a secondary modified attapulgite, which is set aside;

[0071] S13, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (65°C, 0.5 h), washing the mixture after the treatment, then adding the mixture to water, and then adding KH550, treating the mixture under heating conditions (75°C, 1 h). After the treatment, filtering, washing, and drying the mixture to obtain modified carbon nanotubes; wherein the ratio of carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g:4.6 g:0.62 mL:12 mL;

[0072] S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a dopamine-containing buffer solution (Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1, pH 8), soaking them (at room temperature for 12 hours), and then centrifuging and filtering them to obtain a composite material; wherein the ratio of the secondary modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g:8 mL:0.42;

[0073] S15. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a ratio of 1:7 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0074] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, and treat them under heating conditions (35°C, 4.5h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.32:10.

[0075] In this embodiment, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0076] Comparative Example 1

[0077] Compared with Example 1, the boric acid modification of the attapulgite was not performed in Comparative Example 1, that is, step S12 was omitted. Specifically, in Comparative Example 1, a TPU material was provided, which was prepared from the following raw materials by weight: 100g TPU, 30g multifunctional additive, 1.5g antioxidant 1010, and 2g zinc stearate.

[0078] The preparation of the multi-functional additive comprises the following steps:

[0079] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.45 and then subjected to high temperature treatment (790°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0080] S12, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (60°C, 0.5 h), washing the mixture after the treatment, then adding the mixture to water, and then adding KH550, treating the mixture under heating conditions (75°C, 1 h). After the treatment, filtering, washing, and drying the mixture to obtain modified carbon nanotubes; wherein the amount ratio of the carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g:5 g:0.55 mL:15 mL;

[0081] S13, adding the pre-modified attapulgite obtained in step S11 and the modified carbon nanotubes obtained in step S12 to a dopamine-containing buffer solution (Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1, pH value 8), soaking them (at room temperature for 12 hours), and then centrifuging and filtering them to obtain a composite material; wherein the amount ratio of the pre-modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g:8 mL:0.35;

[0082] S14. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a ratio of 1:6 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0083] S15. Add the composite material obtained in step S13 and the modified silicon dioxide obtained in step S14 to water, and treat them under heating conditions (35°C, 4h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.3:10.

[0084] In this comparative example, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0085] Comparative Example 2

[0086] Compared with Example 1, KH550 was not used in the treatment process of step S13 in Comparative Example 2. Specifically, in Comparative Example 2, a TPU material was provided, which was prepared from the following raw materials by weight: 100g TPU, 30g multifunctional additive, 1.5g antioxidant 1010, and 2g zinc stearate.

[0087] The preparation of the multi-functional additive comprises the following steps:

[0088] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.45 and then subjected to high temperature treatment (790°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0089] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid (0.05 g / mL) at a mass ratio of 2.5:1, heating and stirring (65°C, 8 min), centrifuging and filtering, washing to neutrality, and drying to obtain a secondary modified attapulgite, which is set aside;

[0090] S13, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (60°C, 0.5 h), washing and drying after the treatment to obtain modified carbon nanotubes; wherein the amount ratio of carbon nanotubes, concentrated nitric acid, and water is 1 g:5 g:15 mL;

[0091] S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a dopamine-containing buffer solution (Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1, pH 8), soaking them (at room temperature for 12 hours), and then centrifuging and filtering them to obtain a composite material; wherein the amount ratio of the secondary modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g:8 mL:0.35;

[0092] S15. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a dosage ratio of 1:6 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0093] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, and treat them under heating conditions (35°C, 4h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.3:10.

[0094] In this comparative example, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0095] Comparative Example 3

[0096] Compared with Example 1, in Comparative Example 3, dopamine was not used during the treatment process in step S14, but was replaced with water. Specifically, in Comparative Example 3, a TPU material was provided, which was prepared from the following raw materials by weight: 100g TPU, 30g multifunctional additive, 1.5g antioxidant 1010, and 2g zinc stearate.

[0097] The preparation of the multi-functional additive comprises the following steps:

[0098] S11. Pre-modification of attapulgite: attapulgite and sodium hydroxide were mixed uniformly in a mass ratio of 1:0.45 and then subjected to high temperature treatment (790°C, 0.5h). After the treatment, the mixture was crushed to obtain pre-modified attapulgite.

[0099] S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid (0.05 g / mL) at a mass ratio of 2.5:1, heating and stirring (65°C, 8 min), centrifuging and filtering, washing to neutrality, and drying to obtain a secondary modified attapulgite, which is set aside;

[0100] S13, adding the carbon nanotubes to concentrated nitric acid (6 mol / L) for acidification (60°C, 0.5 h), washing the mixture after the treatment, then adding the mixture to water, and then adding KH550, treating the mixture under heating conditions (75°C, 1 h). After the treatment, filtering, washing, and drying the mixture to obtain modified carbon nanotubes; wherein the amount ratio of the carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g:5 g:0.55 mL:15 mL;

[0101] S14. Add the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to water, soak them (at room temperature for 12 hours), and then centrifuge to obtain a composite material; wherein the ratio of the secondary modified attapulgite, water, and modified carbon nanotubes is 1 g:8 mL:0.35;

[0102] S15. Place silica in a mixed solution (concentrated sulfuric acid and hydrogen peroxide solution mixed in a volume ratio of 7:3) at a dosage ratio of 1:6 mL and treat (room temperature, 0.5 h). After the treatment, wash the solution to obtain modified silica for later use.

[0103] S16. Add the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, and treat them under heating conditions (35°C, 4h). After the treatment, wash, dry, and crush to obtain a multi-functional additive; wherein the mass ratio of the composite material, the modified silicon dioxide, and water is 1:0.3:10.

[0104] In this embodiment, a preparation process of the above-mentioned TPU material is also provided, comprising the following steps: weighing the raw material components in proportion and mixing them evenly, and then feeding them into a twin-screw granulator for granulation (processing temperature is 170°C, speed is 120 rpm).

[0105] The performance test of the TPU materials prepared in Example 1 and Comparative Examples 1 to 3 was carried out as follows:

[0106] The antistatic performance is tested in accordance with GBT 1410-2006; the flame retardant performance is tested in accordance with UL-94 standard; the elongation at break is tested in accordance with GB / T1040.1-2018; and the tensile performance is tested in accordance with GB / T1040.1-2018.

[0107] The test results are shown in Table 1.

[0108] Table 1 Test results

[0109]

[0110] As can be seen from Table 1, the TPU material prepared by the present invention has good flame retardancy, good antistatic performance, and excellent mechanical properties.

[0111] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A TPU material, characterized in that: The invention is prepared from the following raw materials in parts by weight: 80 to 120 parts of TPU, 20 to 35 parts of multifunctional additives, 0.2 to 2.5 parts of antioxidants, and 0.2 to 2 parts of heat stabilizers; The preparation of the multi-functional additive comprises the following steps: S11, pre-modification of attapulgite: the attapulgite is mixed evenly with sodium hydroxide and then subjected to high temperature treatment. After the treatment is completed, the mixture is crushed to obtain pre-modified attapulgite; S12, adding the pre-modified attapulgite obtained in step S11 to an ethanol solution containing boric acid, heating and stirring, centrifuging and filtering, washing to neutrality, and drying to obtain secondary modified attapulgite, which is set aside; S13, adding the carbon nanotubes to concentrated nitric acid for acidification, washing after the treatment, then adding to water, then adding KH550, treating under heating conditions, filtering, washing, and drying after the treatment to obtain modified carbon nanotubes; S14, adding the secondary modified attapulgite obtained in step S12 and the modified carbon nanotubes obtained in step S13 to a buffer solution containing dopamine, soaking them, and then centrifuging and filtering them to obtain a composite material; S15, placing the silicon dioxide in the mixed solution for treatment, and washing it after the treatment is completed to obtain modified silicon dioxide for standby use; S16, adding the composite material obtained in step S14 and the modified silicon dioxide obtained in step S15 to water, treating them under heating conditions, and after the treatment is completed, washing, drying, and crushing to obtain a multifunctional additive; In step S12, the concentration of boric acid in the ethanol solution is 0.04-0.08 g / mL; the mass ratio of boric acid to pre-modified attapulgite is 1:1.5-2.8; the heating and stirring treatment temperature is 60-75° C., and the treatment time is 5-10 min.

2. A TPU material according to claim 1, characterized in that, The antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168; and the heat stabilizer is selected from one or both of calcium stearate and zinc stearate.

3. A TPU material according to claim 1, characterized in that, In step S11, the mass ratio of attapulgite to sodium hydroxide is 1:0.35-0.65; the high temperature treatment temperature is 780-805° C., and the treatment time is 0.5-4 h.

4. A TPU material according to claim 1, characterized in that, In step S13, the usage ratio of carbon nanotubes, concentrated nitric acid, KH550, and water is 1 g: 4-8 g: 0.5-0.8 mL: 12-20 mL; the concentration of concentrated nitric acid is 4-6.5 mol / L; the acidification treatment temperature is 55-75° C., and the treatment time is 0.5-4 h; the heating temperature is 65-85° C., and the treatment time under heating conditions is 1-4 h.

5. A TPU material according to claim 1, characterized in that, In step S14, the dopamine-containing buffer solution is obtained by mixing Tris-HCl buffer solution and dopamine hydrochloride in a mass ratio of 1:1; the pH value of the dopamine-containing buffer solution is 7.8-8.5; the amount ratio of the secondary modified attapulgite, the dopamine-containing buffer solution, and the modified carbon nanotubes is 1 g: 5-10 mL: 0.25-0.5; the immersion treatment temperature is room temperature, and the treatment time is 8-16 h.

6. A TPU material according to claim 2, characterized in that, In step S15, the mixed solution is obtained by mixing concentrated sulfuric acid and hydrogen peroxide solution in a volume ratio of 7:3; the amount ratio of silicon dioxide to the mixed solution is 1 g: 4-12 mL; the treatment temperature is room temperature, and the treatment time is 0.5-4 h.

7. A TPU material according to claim 2, characterized in that, In step S16, the mass ratio of the composite material, modified silicon dioxide and water is 1:0.25-0.45:8-15; the heating temperature is 30-40° C., and the treatment time is 2-6 hours.

8. A process for preparing the TPU material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: weighing various raw material components in proportion, mixing them evenly, and then feeding them into a twin-screw granulator for granulation.

9. The preparation process according to claim 8, characterized in that: The processing temperature of the twin-screw granulator is 160-175°C, and the screw speed is 120-200 rpm.

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