Preparation method of an antibacterial modified thermoplastic polyurethane elastomer

Abstract

The present invention relates to the technical field of polyurethanes, and discloses a preparation method of an antibacterial modified thermoplastic polyurethane elastomer. In the present invention, 1-hydroxymethyl-5,5-dimethylhydantoin and N-(2-hydroxyethyl)ethylenediamine are used as raw materials, and through reaction, intermediate 1 is prepared. Then, it is reacted with monocyanamide to obtain intermediate 2. The hydroxyl group contained in intermediate 2 is used for substitution reaction with phenylphosphonic dichloride to obtain intermediate 3. Intermediate 3 is chlorinated by sodium hypochlorite to obtain a guanidine-containing haloamine phenyl phosphate. Montmorillonite and the guanidine-containing haloamine phenyl phosphate are added to the thermoplastic polyurethane elastomer, mixed evenly, extruded and granulated, and compression molded to obtain the antibacterial modified thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer prepared by the present invention has excellent antibacterial performance and flame retardant performance.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane, in particular to a method for preparing an antibacterial modified thermoplastic polyurethane elastomer. Background Art

[0002] Polyurethane refers to a type of polymer containing a large number of repeated carbamate groups in the molecular chain structure. Thermoplastic polyurethane elastomer, referred to as TPU, is a new type of synthetic material between rubber and plastic. It is mainly made of isocyanate, polyol and chain extender through polymerization reaction. It has excellent mechanical properties and wear resistance, and is widely used in transportation, agricultural production, construction and building materials. However, its antibacterial properties are poor, which limits its application in some fields.

[0003] Montmorillonite is a natural silicate mineral with excellent thermal stability, adsorption, impact resistance and other properties, and is widely used in adsorbents, catalysts and other fields. For example, the patent application publication number is CN109134821A, which discloses a flame retardant thermoplastic polyurethane elastomer and a preparation method thereof. The invention uses polytetramethylene ether glycol, organic montmorillonite, mixed flame retardant and the like as raw materials, and the prepared thermoplastic polyurethane elastomer has excellent flame retardant properties, but does not improve the antibacterial properties of the polyurethane elastomer. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies of the prior art, the present invention provides a method for preparing an antibacterial modified thermoplastic polyurethane elastomer. The prepared thermoplastic polyurethane elastomer has excellent antibacterial and flame retardant properties.

[0006] (II) Technical solution

[0007] A method for preparing an antibacterial modified thermoplastic polyurethane elastomer, the preparation method is as follows:

[0008] Thermoplastic polyurethane elastomer, montmorillonite, and guanidine-containing halogenamine phenyl phosphate are added to a high-speed mixer and mixed evenly. The mixture is added to a twin-screw extruder, extruded into granules, and finally placed in a flat vulcanizer at 180° C. and 10 MPa for pressing to obtain an antibacterial modified thermoplastic polyurethane elastomer.

[0009] Preferably, the temperatures of the three zones of the twin-screw extruder are 170°C, 180°C and 175°C.

[0010] Preferably, the mass ratio of the thermoplastic polyurethane elastomer, montmorillonite and guanidine-containing halogenamine phenyl phosphate is 100:(15-30):(1-8).

[0011] Preferably, the preparation method of the guanidine-based haloamine phenyl phosphate is as follows:

[0012] (1) Add 1-hydroxymethyl-5,5-dimethylhydantoin to isopropanol solvent, stir and disperse, then add N-(2-hydroxyethyl)ethylenediamine thereto, and react at 20-35 °C for 3-6 h. After the reaction is completed, carry out vacuum distillation to obtain intermediate 1.

[0013] (2) Add monocyanamide to isopropanol solvent, stir and disperse, adjust the pH to 4-5 with 2-5 mol / L hydrochloric acid, then add intermediate 1 thereto, and react at 10-25 °C for 8-16 h. After the reaction is completed, carry out vacuum distillation to obtain intermediate 2.

[0014] (3) Under nitrogen atmosphere, add intermediate 2 to tetrahydrofuran solvent, stir and disperse, then add phenylphosphonic dichloride and triethylamine thereto, heat up to 60-70 °C, and react for 20-36 h. After the reaction is completed, filter, rotary evaporate, wash with deionized water, and dry to obtain intermediate 3.

[0015] (4) Add intermediate 3 to deionized water, stir and disperse, then add sodium hypochlorite thereto, adjust the pH to 7-8 with 0.4 mol / L sulfuric acid, and stir and react at 20-35 °C for 3-6 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain the guanidine-based haloamine phenyl phosphate.

[0016] Preferably, in the step (1), the molar ratio of 1-hydroxymethyl-5,5-dimethylhydantoin to N-(2-hydroxyethyl)ethylenediamine is 1:(1-1.2).

[0017] Preferably, in the step (2), the molar ratio of monocyanamide to intermediate 1 is (1-1.5):1.

[0018] Preferably, in the step (3), the molar ratio of intermediate 2, phenylphosphonic dichloride, and triethylamine is (2-3):1:(2.2-2.6).

[0019] Preferably, in the step (4), the molar ratio of intermediate 3 to sodium hypochlorite is 1:(2.5-4).

[0020] (III) Beneficial technical effects

[0021] The present invention uses 1-hydroxymethyl-5,5-dimethylhydantoin, N-(2-hydroxyethyl)ethylenediamine, monocyanamide, phenylphosphonic dichloride, sodium hypochlorite, etc. as raw materials, and prepares the guanidine-based haloamine phenyl phosphate through reactions. Montmorillonite and the guanidine-based haloamine phenyl phosphate are added to thermoplastic polyurethane elastomer, mixed evenly, extruded and granulated, and compression molded to obtain the antibacterial modified thermoplastic polyurethane elastomer.

[0022] The guanidine-based haloamine phenyl phosphate prepared by the present invention through a series of reactions has a simple preparation method and a novel structure. Due to the presence of a biguanidine structure and a dihaloamine structure therein, when it is added to a thermoplastic polyurethane elastomer, its antibacterial effect is superior to that of a single guanidine group and a haloamine structure. And because the guanidine-based haloamine phenyl phosphate contains more phosphorus and nitrogen elements, both of which are flame-retardant elements, when it is added to a thermoplastic polyurethane elastomer, the phosphorus element generates strongly dehydrating substances such as phosphoric acid and metaphosphoric acid when heated, which can promote the dehydration and carbonization of the material and form a dense carbon layer on the surface of the material to isolate the transport of substances and the transfer of energy. The nitrogen element therein can generate non-flammable gases when heated, diluting the content of flammable gases in the air and further improving the flame-retardant performance of the material. The thermoplastic polyurethane elastomer prepared by the present invention has excellent antibacterial and flame-retardant properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the preparation route of the guanidine-based haloamine phenyl phosphate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] Example 1

[0026] (1) 0.1 mol of 1-hydroxymethyl-5,5-dimethylhydantoin was added to 200 mL of isopropanol solvent, stirred and dispersed, and then 0.12 mol of N-(2-hydroxyethyl)ethylenediamine was added thereto. The reaction was carried out at 25 °C for 4 h. After the reaction was completed, it was distilled under reduced pressure to obtain Intermediate 1.

[0027] (2) 0.25 mol of monocyanamide was added to 200 mL of isopropanol solvent, stirred and dispersed, the pH was adjusted to 5 with 5 mol / L hydrochloric acid, and then 0.2 mol of Intermediate 1 was added thereto. The reaction was carried out at 20 °C for 10 h. After the reaction was completed, it was distilled under reduced pressure to obtain Intermediate 2.

[0028] (3) Under nitrogen conditions, 0.35 mol of Intermediate 2 was added to 200 mL of tetrahydrofuran solvent, stirred and dispersed, and then 0.15 mol of phenylphosphonic dichloride and 0.35 mol of triethylamine were added thereto. The temperature was raised to 65 °C and the reaction was carried out for 26 h. After the reaction was completed, it was filtered, rotary evaporated, washed with deionized water, and dried to obtain Intermediate 3.

[0029] (4) Add 40 mmol of Intermediate 3 to 100 mL of deionized water, stir to disperse, then add 160 mmol of sodium hypochlorite thereto, adjust the pH to 7 with 0.4 mol / L sulfuric acid, and stir and react at 25 °C for 3 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain guanidyl halamine phenyl phosphate.

[0030] (5) Add 20 g of thermoplastic polyurethane elastomer, 4 g of montmorillonite, and 0.2 g of guanidyl halamine phenyl phosphate to a high-speed mixer, mix evenly, add the mixture to a twin-screw extruder, extrude and pelletize. The temperatures of the three zones of the twin-screw extruder are 170 °C, 180 °C, and 175 °C. Finally, place it in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain antibacterial modified thermoplastic polyurethane elastomer.

[0031] Example 2

[0032] (1) Add 0.1 mol of 1-hydroxymethyl-5,5-dimethylhydantoin to 200 mL of isopropanol solvent, stir to disperse, then add 0.1 mol of N-(2-hydroxyethyl)ethylenediamine thereto, and react at 35 °C for 3 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 1.

[0033] (2) Add 0.25 mol of monocyanamide to 200 mL of isopropanol solvent, stir to disperse, adjust the pH to 5 with 3 mol / L hydrochloric acid, then add 0.2 mol of Intermediate 1 thereto, and react at 15 °C for 10 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 2.

[0034] (3) Under nitrogen atmosphere, add 0.35 mol of Intermediate 2 to 200 mL of tetrahydrofuran solvent, stir to disperse, then add 0.15 mol of phenylphosphonic dichloride and 0.35 mol of triethylamine thereto, heat up to 65 °C, and react for 25 h. After the reaction is completed, filter, rotary evaporate, wash with deionized water, and dry to obtain Intermediate 3.

[0035] (4) Add 40 mmol of Intermediate 3 to 100 mL of deionized water, stir to disperse, then add 150 mmol of sodium hypochlorite thereto, adjust the pH to 7 with 0.4 mol / L sulfuric acid, and stir and react at 35 °C for 6 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain guanidyl halamine phenyl phosphate.

[0036] (5) Add 20 g of thermoplastic polyurethane elastomer, 4 g of montmorillonite, and 0.5 g of guanidine-based haloamine phenyl phosphate into a high-speed mixer, mix evenly, add the mixture into a twin-screw extruder, extrude and pelletize. The temperatures of the three zones of the twin-screw extruder are 170 °C, 180 °C, and 175 °C. Finally, place it in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain the antibacterial modified thermoplastic polyurethane elastomer.

[0037] Example 3

[0038] (1) Add 0.1 mol of 1-hydroxymethyl-5,5-dimethylhydantoin into 200 mL of isopropanol solvent, stir and disperse, then add 0.11 mol of N-(2-hydroxyethyl)ethylenediamine thereto, react at 20 °C for 6 h. After the reaction is completed, perform vacuum distillation to obtain Intermediate 1.

[0039] (2) Add 0.2 mol of monocyanamide into 200 mL of isopropanol solvent, stir and disperse, adjust the pH to 5 with 4 mol / L hydrochloric acid, then add 0.2 mol of Intermediate 1 thereto, react at 10 °C for 16 h. After the reaction is completed, perform vacuum distillation to obtain Intermediate 2.

[0040] (3) Under nitrogen atmosphere, add 0.35 mol of Intermediate 2 into 200 mL of tetrahydrofuran solvent, stir and disperse, then add 0.15 mol of phenylphosphonic dichloride and 0.35 mol of triethylamine thereto, heat up to 60 °C, react for 20 h. After the reaction is completed, filter, perform rotary evaporation, wash with deionized water, and dry to obtain Intermediate 3.

[0041] (4) Add 40 mmol of Intermediate 3 into 100 mL of deionized water, stir and disperse, then add 100 mmol of sodium hypochlorite thereto, adjust the pH to 8 with 0.4 mol / L sulfuric acid, stir and react at 20 °C for 4 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain guanidine-based haloamine phenyl phosphate.

[0042] (5) Add 20 g of thermoplastic polyurethane elastomer, 5 g of montmorillonite, and 1 g of guanidine-based haloamine phenyl phosphate into a high-speed mixer, mix evenly, add the mixture into a twin-screw extruder, extrude and pelletize. The temperatures of the three zones of the twin-screw extruder are 170 °C, 180 °C, and 175 °C. Finally, place it in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain the antibacterial modified thermoplastic polyurethane elastomer.

[0043] Example 4

[0044] (1) Add 0.1 mol of 1-hydroxymethyl-5,5-dimethylhydantoin to 200 mL of isopropanol solvent, stir to disperse, then add 0.12 mol of N-(2-hydroxyethyl)ethylenediamine thereto, and react at 30 °C for 6 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 1.

[0045] (2) Add 0.3 mol of monocyanamide to 200 mL of isopropanol solvent, stir to disperse, adjust the pH to 4 with 2 mol / L hydrochloric acid, then add 0.2 mol of Intermediate 1 thereto, and react at 25 °C for 12 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 2.

[0046] (3) Under nitrogen atmosphere, add 0.45 mol of Intermediate 2 to 200 mL of tetrahydrofuran solvent, stir to disperse, then add 0.15 mol of phenylphosphonic dichloride and 0.33 mol of triethylamine thereto, heat up to 70 °C, and react for 36 h. After the reaction is completed, filter, rotary evaporate, wash with deionized water, and dry to obtain Intermediate 3.

[0047] (4) Add 40 mmol of Intermediate 3 to 100 mL of deionized water, stir to disperse, then add 140 mmol of sodium hypochlorite, adjust the pH to 8 with 0.4 mol / L sulfuric acid, and stir and react at 25 °C for 5 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain guanidine-based haloamine phenyl phosphate.

[0048] (5) Add 20 g of thermoplastic polyurethane elastomer, 3 g of montmorillonite, and 1.4 g of guanidine-based haloamine phenyl phosphate to a high-speed mixer, mix evenly, add the mixture to a twin-screw extruder, extrude and pelletize. The temperatures of the three zones of the twin-screw extruder are 170 °C, 180 °C, and 175 °C. Finally, place it in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain antibacterial modified thermoplastic polyurethane elastomer.

[0049] Example 5

[0050] (1) Add 0.1 mol of 1-hydroxymethyl-5,5-dimethylhydantoin to 200 mL of isopropanol solvent, stir to disperse, then add 0.1 mol of N-(2-hydroxyethyl)ethylenediamine thereto, and react at 35 °C for 6 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 1.

[0051] (2) Add 0.25 mol of monocyanamide to 200 mL of isopropanol solvent, stir to disperse, adjust the pH to 4 with 5 mol / L hydrochloric acid, then add 0.2 mol of Intermediate 1 thereto, and react at 15 °C for 8 h. After the reaction is completed, distill under reduced pressure to obtain Intermediate 2.

[0052] (3) Under nitrogen conditions, 0.3 mol of intermediate 2 was added to 200 mL of tetrahydrofuran solvent, stirred and dispersed, then 0.15 mol of phenylphosphonic dichloride and 0.39 mol of triethylamine were added thereto, the temperature was raised to 65 °C, and the reaction was carried out for 24 h. After the reaction was completed, filtration, rotary evaporation, washing with deionized water, and drying were carried out to obtain intermediate 3.

[0053] (4) 40 mmol of intermediate 3 was added to 100 mL of deionized water, stirred and dispersed, then 120 mmol of sodium hypochlorite was added thereto, and the pH was adjusted to 7 with 0.4 mol / L sulfuric acid. The reaction was carried out with stirring at 25 °C for 2 h. After the reaction was completed, centrifugation, washing with deionized water, and drying were carried out to obtain guanidine-based haloamine phenyl phosphate.

[0054] (5) 20 g of thermoplastic polyurethane elastomer, 6 g of montmorillonite, and 1.6 g of guanidine-based haloamine phenyl phosphate were added to a high-speed mixer and mixed evenly. The mixture was added to a twin-screw extruder for extrusion granulation. The temperatures of the three zones of the twin-screw extruder were 170 °C, 180 °C, and 175 °C. Finally, it was placed in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain an antibacterial modified thermoplastic polyurethane elastomer.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that in step (5), intermediate 2 was used instead of guanidine-based haloamine phenyl phosphate.

[0057] Referring to GB / T 2406, using a limiting oxygen index tester, the LOI of the material was tested, and the sample size was 75 mm × 6.5 mm × 3 mm.

[0058] Referring to GB / T 2408, using a vertical burning tester, the vertical burning grade of the material was tested, and the sample size was 125 mm × 13 mm × 3 mm.

[0059] Table 1: Flame retardancy test results of each example and comparative example

[0060]

[0061]

[0062] As can be seen from the table, the flame retardancy effect of Examples 1-5 is better than that of Comparative Example 1. This is because in Examples 1-5, guanidine-based haloamine phenyl phosphate is contained, and the phosphorus element contained in guanidine-based haloamine phenyl phosphate has a good flame retardancy effect. When it is added to the thermoplastic elastomer, it can increase the flame retardancy effect of the elastomer, while such a substance is not present in Comparative Example 1. Therefore, its flame retardancy effect is inferior to that of Examples 1-5.

[0063] Antibacterial test: Use a sterile cotton swab to scrape Staphylococcus aureus and Escherichia coli, place them in a sodium chloride - peptone buffer solution with pH = 7.0, dip a sterile cotton swab into a bacterial suspension with a content of 6×10 6 cfu / mL, evenly spread it on the surface of a tryptic soy agar medium plate, place a sample with a diameter of 5 mm on the contaminated plate, at the center of the petri dish, cover the petri dish, and culture it in an incubator at 32°C for 24 h. After the culture is completed, use a vernier caliper to measure the diameter of the inhibition zone.

[0064] Table 2: Antibacterial performance test results of each example and comparative example

[0065]

[0066]

[0067] Comparative example 2 is pure thermoplastic polyurethane elastomer.

[0068] As can be seen from the table, the antibacterial performance test results of Examples 1 - 5 and Comparative example 1 are better than those of Comparative example 2. This is because Examples 1 - 5 and Comparative example 1 contain guanidine groups and haloamine structures, which are antibacterial structures. Therefore, adding them to thermoplastic polyurethane can increase the antibacterial performance of thermoplastic polyurethane elastomer. Thus, the thermoplastic polyurethane elastomer prepared by the present invention has excellent antibacterial effects.

[0069] The above - described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A preparation method of an antibacterial modified thermoplastic polyurethane elastomer, characterized in that, The preparation method is as follows: Add thermoplastic polyurethane elastomer, montmorillonite, and guanidine-containing haloamine phenyl phosphate into a high-speed mixer, mix evenly, add the mixture into a twin-screw extruder, extrude and granulate, and finally place it in a flat vulcanizing machine at 180 °C and 10 MPa for pressing to obtain antibacterial modified thermoplastic polyurethane elastomer; The preparation method of the guanidine-containing haloamine phenyl phosphate is as follows: (1) Add 1-hydroxymethyl-5,5-dimethylhydantoin into an isopropanol solvent, stir and disperse, then add N-(2-hydroxyethyl)ethylenediamine thereto, and react at 20 - 35 °C for 3 - 6 h. After the reaction is completed, carry out vacuum distillation to obtain Intermediate 1, and its structural formula is: (2) Add monocyanamide into an isopropanol solvent, stir and disperse, adjust the pH to 4 - 5 with 2 - 5 mol / L hydrochloric acid, then add Intermediate 1 thereto, and react at 10 - 25 °C for 8 - 16 h. After the reaction is completed, carry out vacuum distillation to obtain Intermediate 2, and its structural formula is: (3) Under nitrogen atmosphere, add Intermediate 2 into a tetrahydrofuran solvent, stir and disperse, then add phenylphosphonic dichloride and triethylamine thereto, heat up to 60 - 70 °C, and react for 20 - 36 h. After the reaction is completed, filter, rotary evaporate, wash with deionized water, and dry to obtain Intermediate 3, and its structural formula is: (4) Add Intermediate 3 into deionized water, stir and disperse, then add sodium hypochlorite thereto, adjust the pH to 7 - 8 with 0.4 mol / L sulfuric acid, and stir and react at 20 - 35 °C for 3 - 6 h. After the reaction is completed, centrifuge, wash with deionized water, and dry to obtain guanidine-containing haloamine phenyl phosphate, and its structural formula is:

2. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, characterized in that, The temperatures of the three zones of the twin-screw extruder are 170 °C, 180 °C, and 175 °C.

3. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, characterized in that, The mass ratio of the thermoplastic polyurethane elastomer, montmorillonite, and guanidine-containing haloamine phenyl phosphate is 100:(15 - 30):(1 - 8).

4. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, wherein, In the step (1), the molar ratio of 1-hydroxymethyl-5,5-dimethylhydantoin to N-(2-hydroxyethyl)ethylenediamine is 1:(1 - 1.2).

5. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, characterized in that, In the step (2), the molar ratio of monocyanamide to Intermediate 1 is (1 - 1.5):

1.

6. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, characterized in that, In the step (3), the molar ratio of Intermediate 2, phenylphosphonic dichloride, and triethylamine is (2 - 3):1:(2.2 - 2.6).

7. The preparation method of the antibacterial modified thermoplastic polyurethane elastomer according to claim 1, wherein In the step (4), the molar ratio of Intermediate 3 to sodium hypochlorite is 1:(2.5 - 4).

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