An antibacterial thermoplastic polyurethane elastomer and a method for preparing the same

Abstract

This invention relates to an antibacterial thermoplastic polyurethane elastomer, comprising the following components: 93.5-98.7 parts of thermoplastic polyurethane elastomer, 0.1-2 parts of ketone-aldehyde-amine condensate, 0.1-1 parts of silver ion antibacterial agent, 0.1-0.5 parts of antioxidant, and 1-3 parts of dispersant. The thermoplastic polyurethane elastomer of this invention exhibits long-lasting antibacterial properties and excellent colorfastness.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to an antibacterial thermoplastic polyurethane elastomer and its preparation method. Background Technology

[0002] As a high-performance material, thermoplastic polyurethane elastomer has been widely used in the field of polymer materials due to its good elasticity, wear resistance, low temperature resistance, oil resistance and tensile strength. The products made from it cover the categories of industrial applications and civilian necessities.

[0003] With the upgrading and iteration of smart wearable products, the demand for antibacterial thermoplastic polyurethane elastomers has surged. Due to the biocompatibility requirements for cytotoxicity and skin irritation in smart wearable products, silver-based antibacterial agents are currently the main component in antibacterial thermoplastic polyurethane elastomers. However, the high chemical reactivity of silver ions makes them prone to chemical reactions that produce colored substances such as silver oxide. Therefore, thermoplastic polyurethane elastomers are prone to discoloration when exposed to high temperature, high humidity, acid, or alkali environments, which cannot meet the requirements for colored products.

[0004] Patent CN115286766A discloses an antibacterial thermoplastic polyurethane elastomer material and its preparation method. It introduces thiol groups into the molecular chain through thiol end-capping. However, a drawback is that the thiol groups have a foul odor, making this antibacterial thermoplastic polyurethane elastomer unsuitable for use in smart wearable products. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing an antibacterial thermoplastic polyurethane elastomer. The present invention controls the dissolution state of silver ions in the matrix by coordinating the ketone-aldehyde-amine condensate with silver ions, thereby slowing down the reaction rate of silver ions being oxidized or reduced, and providing excellent colorfastness while prolonging the antibacterial effect of the material.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight:

[0008] 93.5-98.7 parts of thermoplastic polyurethane elastomer, preferably 95-98 parts;

[0009] 0.1-2 parts of ketone-aldehyde-amine condensate,

[0010] 0.1-1 part silver ion antibacterial agent

[0011] 0.1-0.5 parts antioxidant,

[0012] 1-3 parts dispersant.

[0013] In this invention, preferably, the thermoplastic polyurethane elastomer includes any one or more of polyester-based thermoplastic polyurethane elastomers and polyether-based thermoplastic polyurethane elastomers;

[0014] Preferably, the number average molecular weight of the thermoplastic polyurethane elastomer is 20,000-200,000 g / mol, for example, it can be 30,000 g / mol, 50,000 g / mol, 70,000 g / mol, 90,000 g / mol, 110,000 g / mol, 130,000 g / mol, 150,000 g / mol, 170,000 g / mol or 190,000 g / mol, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific values ​​included in the range, but further preferably 60,000-150,000 g / mol.

[0015] Preferably, the Shore hardness of the thermoplastic polyurethane elastomer is 50A-82D, for example, it can be 55A, 60A, 70A, 75A, 80A, 85A, 90A, 95A, 60D, 65D, 70D, 75D or 80D, and more preferably 60A-72D.

[0016] Preferably, the ketaldehyde-amine condensate contains the following general structural formula:

[0017]

[0018] Wherein, R1 is aryl or alkyl, preferably -CH3 or phenyl, R2 and R3 are hydrogen atoms or alkyl groups having 1 to 8 carbon atoms, more preferably hydrogen atoms, methyl, ethyl, propyl, butyl, pentyl, isobutyl, hexyl, heptyl, octyl, and even more preferably hydrogen atoms or octyl, and R2 and R3 are different.

[0019] More preferably, the aldehyde-ketone-amine condensate is:

[0020]

[0021] Preferably, the silver ion antibacterial agent is one or more of the following: glass-loaded silver antibacterial agent, zirconium phosphate-loaded silver antibacterial agent, titanium phosphate-loaded silver antibacterial agent, zeolite-loaded silver antibacterial agent, montmorillonite-loaded silver antibacterial agent, sodium zirconium phosphate-loaded silver antibacterial agent, hydroxyapatite-loaded silver antibacterial agent, titanium dioxide-loaded silver antibacterial agent, silica-loaded silver antibacterial agent, zirconium oxide-loaded silver antibacterial agent, magnesium pyrophosphate-loaded silver antibacterial agent, boron nitride-loaded silver antibacterial agent, and ferrite oxide complex-loaded silver antibacterial agent.

[0022] Preferably, the dispersant is one or a combination of alkane-based, ester-based, and amide-based dispersants. More preferably, the dispersant is one or a combination of polyethylene wax, EBS, and their derivatives. Even more preferably, the dispersant is one or two of polyethylene wax or EBS.

[0023] Preferably, the antioxidant is one or more of hindered phenolic antioxidants; more preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 264, antioxidant 168, and antioxidant 1076. Even more preferably, the antioxidant is antioxidant 1010.

[0024] This invention also provides a method for preparing the antibacterial thermoplastic polyurethane elastomer, comprising the following steps:

[0025] S1. Premix the thermoplastic polyurethane elastomer, ketone-aldehyde-amine condensate, silver ion antibacterial agent, antioxidant, and dispersant in a mixer or kneader to obtain a mixed raw material;

[0026] S2. The mixed raw materials are mixed evenly using one or more mixing devices, such as a single-screw extruder, twin-screw extruder, internal mixer, or open mill, to obtain the antibacterial thermoplastic polyurethane elastomer.

[0027] Preferably, in step S1, a mixer is used for mixing, with a mixer speed of 100-300 rpm and a mixing time of 10s-10min.

[0028] Preferably, a twin-screw extruder is used in step S2, and the screw speed of the twin-screw extruder is 100-300 rpm. More preferably, the screw speed of the twin-screw extruder in step S2 is 150-250 rpm;

[0029] Preferably, the twin-screw extruder in step S2 has 10-14 heating zones, and the temperature range from the feed port to the die of the twin-screw extruder is 100-240°C, more preferably 170-220°C.

[0030] The beneficial effects of this invention are:

[0031] The antibacterial thermoplastic polyurethane elastic material provided by this invention can control the dissolution state of silver ions in the matrix through the coordination reaction of the introduced ketone-aldehyde-amine condensate silver ions, slow down the reaction rate of silver ions being oxidized or reduced, and provide excellent colorfastness while prolonging the antibacterial effect of the material; at the same time, this product has no obvious odor and can be used in smart wearables, children's toys, footwear and clothing and other fields. Detailed Implementation

[0032] The present invention will be further described in detail below through specific embodiments.

[0033] Raw material source:

[0034]

[0035] Preparation method of ketone-aldehyde-amine condensate:

[0036] A ketone and aldehyde in a 1:1 molar ratio were poured into a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. After thorough mixing, 15% hydrochloric acid solution was added to maintain the pH of the medium at around 6. The mixture was heated to 90°C and held at this temperature for 5 hours. During this process, the reflux condenser was turned on. After the reaction was completed, the mixture was allowed to stand for 5 hours, and the lower layer of water was released to obtain a ketone-aldehyde condensate. Then, an amine of the same molar amount as the ketone or aldehyde was added, and the mixture was stirred thoroughly. The temperature was raised to 90°C and held at this temperature for 10 hours. After the reaction was completed, the prepared reagent was cooled to room temperature to obtain the ketone-aldehyde-amine condensate.

[0037] Preparation method:

[0038] Acetone and formaldehyde in a 1:1 molar ratio were poured into a three-necked flask equipped with a stirrer, thermometer, and reflux condenser. After thorough mixing, 15% hydrochloric acid solution was added to maintain the pH of the medium at around 6. The mixture was heated to 90°C and maintained at this temperature for 5 hours, with the reflux condenser turned on during the process. After the reaction was completed, the mixture was allowed to stand for 5 hours, and the lower layer of water was released to obtain the ketone-aldehyde condensate. Then, octylamine in the same molar amount as acetone and formaldehyde was added, and the mixture was stirred thoroughly until the temperature was raised to 90°C. The mixture was then maintained at this temperature for 10 hours. After the reaction was completed, the prepared reagent was cooled to room temperature to obtain the acetone-formaldehyde-octylamine condensate.

[0039] Preparation method:

[0040] By replacing the acetone in the above preparation process with an equimolar amount of acetophenone, the acetophenone-formaldehyde-octylamine condensate can be obtained.

[0041] Example 1

[0042] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight: 97.9 parts of thermoplastic polyurethane elastomer WHT-SW570, 0.1 parts of acetone-formaldehyde-octylamine condensate, 0.5 parts of silver ion antibacterial agent B130, 0.5 parts of antioxidant 1010, and 1 part of polyethylene wax.

[0043] The preparation method includes the following steps:

[0044] S1. Place the thermoplastic polyurethane elastomer, ketone-aldehyde-amine condensate, silver ion antibacterial agent, antioxidant, and dispersant into a mixer. The mixer speed is 200 rpm, and the mixing time is 3 minutes. After mixing, a mixed raw material is obtained.

[0045] S2. Place the mixed raw materials in a twin-screw extruder for melt blending. Set the screw speed to 200 rpm and set the temperature from the feed port to the die head to 175℃, 180℃, 185℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 185℃, and 180℃ respectively, to obtain the antibacterial thermoplastic polyurethane elastomer.

[0046] Example 2

[0047] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight: 96 parts thermoplastic polyurethane elastomer WHT-SW570, 2 parts acetone-formaldehyde-octylamine condensate, 0.5 parts silver ion antibacterial agent B130, 0.5 parts antioxidant 1010, and 2.5 parts polyethylene wax.

[0048] The preparation method is the same as in Example 1, but the extruder temperature is increased by 5°C per zone compared to Example 1.

[0049] Example 3

[0050] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight: 97 parts of thermoplastic polyurethane elastomer WHT-SW570, 1 part of acetone-formaldehyde-octylamine condensate, 0.7 parts of silver ion antibacterial agent RHA-1, 0.5 parts of antioxidant 1010, and 1 part of polyethylene wax.

[0051] The preparation method is the same as in Example 1.

[0052] Example 4

[0053] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight: 96.5 parts of thermoplastic polyurethane elastomer WHT-81080, 1 part of acetophenone-formaldehyde-octylamine condensate, 0.5 parts of silver ion antibacterial agent B130, 0.3 parts of antioxidant 1010, and 2 parts of EBS.

[0054] The preparation method is the same as in Example 1, but the extruder temperature is increased by 5°C per zone compared to Example 1.

[0055] Example 5

[0056] An antibacterial thermoplastic polyurethane elastomer, characterized in that it comprises the following components in parts by weight: 96.5 parts of thermoplastic polyurethane elastomer WHT-81080, 1 part of acetophenone-formaldehyde-octylamine condensate, 0.7 parts of silver ion antibacterial agent RHA-1, 0.5 parts of antioxidant 1010, and 1.5 parts of EBS.

[0057] The preparation method is the same as in Example 1, except that the extruder temperature is increased by 5°C per zone compared to Example 1.

[0058] Comparative Example 1

[0059] An antibacterial thermoplastic polyurethane elastomer comprises the following components in parts by weight: 98 parts thermoplastic polyurethane elastomer WHT-SW570, 0.5 parts silver ion antibacterial agent B130, 0.5 parts antioxidant 1010, and 1 part polyethylene wax.

[0060] The preparation method includes the following steps:

[0061] S1. Place the thermoplastic polyurethane elastomer, silver ion antibacterial agent, antioxidant, and dispersant into a mixer. The mixer speed is 200 rpm, and the mixing time is 3 minutes. After mixing, a mixed raw material is obtained.

[0062] S2. Place the mixed raw materials in a twin-screw extruder for melt blending. Set the screw speed to 200 rpm and set the temperature from the feed port to the die head to 175℃, 180℃, 185℃, 185℃, 190℃, 195℃, 195℃, 190℃, 185℃, 185℃, and 180℃ respectively, to obtain the antibacterial thermoplastic polyurethane elastomer.

[0063] The products prepared in Examples 1-5 and Comparative Example 1 were dried to a moisture content of ≤0.5%, and then injection molded into 50mm*50mm*2mm test pieces. The following test methods were then used for testing:

[0064] Antibacterial rate test: The test strains are Escherichia coli and Staphylococcus aureus, and the test standard is GB / T 31402;

[0065] QUV aging test: Tested according to GB / T16422.3: The entire test process consists of 8 cycles (96 hours), each cycle lasting 12 hours, including UV irradiation (UV-A, 340nm, 0.76W / m). 2 / nm, radiation exposure for 8 hours at black standard temperature 60±3℃, and moisture exposure (non-radiation condensation exposure for 4 hours at black standard temperature 50±3℃). After the test, the color difference was compared with the ΔE of the test piece before and after the test to indicate the magnitude of the color difference, and the presence of yellow spots on the test piece surface was visually checked.

[0066] High temperature and high humidity color change test: 70℃ / 95%RH / 5 days. After the test, use a colorimeter to compare the ΔE of the test piece before and after the test to indicate the magnitude of the color difference.

[0067] Tensile strength: Tested according to ASTM D412, tensile rate 500 mm / min.

[0068] The test results are shown in Table 1.

[0069] Table 1. Performance test results of products from Examples 1-5 and Comparative Example 1

[0070] project Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Antibacterial rate - Escherichia coli 99.9％ 99.9％ 99.9％ 99.9％ 99.9％ 99.9％ Antibacterial rate - Staphylococcus aureus 99.9％ 99.9％ 99.9％ 99.9％ 99.9％ 99.9％ High temperature and high humidity cause color change and color difference 2.37 2.15 2.29 2.40 2.57 5.92 QUV color change and color difference 1.82 1.68 1.73 1.86 1.92 3.65 Surface spots (QUV 96H visual inspection) none none none none none have Tensile strength / MPa 23.6 22.8 22.1 26.9 26.4 23.4

[0071] As shown in Table 1, the antibacterial thermoplastic polyurethane elastomer of the present invention retains excellent antibacterial properties after the addition of the ketone-aldehyde-amine condensate. It also maintains a small color difference after high temperature and humidity and QUV aging, demonstrating good color stability. A comparison of Examples 1, 2, and Comparative Example 1 shows that the ketone-aldehyde-amine condensate has minimal impact on the tensile strength of the material, thus preserving its strength to a large extent.

[0072] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. An antibacterial thermoplastic polyurethane elastomer, characterized in that, The components include the following parts by weight: 93.5-98.7 parts, preferably 95-98 parts, of thermoplastic polyurethane elastomer; 0.1-2 parts of ketone-aldehyde-amine condensate; 0.1-1 part silver ion antibacterial agent; 0.1-0.5 parts antioxidant; 1-3 parts dispersant.

2. The antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The thermoplastic polyurethane elastomer includes any one or more of polyester-based thermoplastic polyurethane elastomers and polyether-based thermoplastic polyurethane elastomers.

3. An antibacterial thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that: The number-average molecular weight of the thermoplastic polyurethane elastomer is 20,000-200,000 g / mol, more preferably 60,000-150,000 g / mol.

4. An antibacterial thermoplastic polyurethane elastomer according to any one of claims 1-3, characterized in that: The thermoplastic polyurethane elastomer has a Shore hardness of 50A-82D, more preferably 60A-72D.

5. The antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The ketaldehyde-amine condensate contains the following general structural formula: Wherein, R1 is aryl or alkyl, preferably -CH3 or phenyl; R2 and R3 are hydrogen atoms or alkyl groups having 1 to 8 carbon atoms, more preferably hydrogen atoms, methyl, ethyl, propyl, butyl, pentyl, isobutyl, hexyl, heptyl, octyl, and even more preferably hydrogen atoms or octyl, and R2 and R3 are different.

6. The antibacterial thermoplastic polyurethane elastomer according to claim 5, characterized in that, The aldehyde-ketone-amine condensate is one or a combination of two of the following structures:

7. The antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The silver ion antibacterial agent is one or more of the following: glass-loaded silver antibacterial agent, zirconium phosphate-loaded silver antibacterial agent, titanium phosphate-loaded silver antibacterial agent, zeolite-loaded silver antibacterial agent, montmorillonite-loaded silver antibacterial agent, sodium zirconium hydroxyphosphate-loaded silver antibacterial agent, hydroxyapatite-loaded silver antibacterial agent, titanium dioxide-loaded silver antibacterial agent, silica-loaded silver antibacterial agent, zirconium oxide-loaded silver antibacterial agent, magnesium pyrophosphate-loaded silver antibacterial agent, boron nitride-loaded silver antibacterial agent, and ferrite oxide complex-loaded silver antibacterial agent.

8. The antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that: The dispersant is one or a combination of alkane, ester, and amide dispersants. More preferably, the dispersant is one or a combination of polyethylene wax, EBS and its derivatives. More preferably, the dispersant is one or two of polyethylene wax or EBS.

9. The antibacterial thermoplastic polyurethane elastomer according to claim 1, characterized in that, The antioxidant is one or more of hindered phenolic antioxidants, more preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 264, antioxidant 168 and antioxidant 1076, and even more preferably, the antioxidant is antioxidant 1010.

10. A method for preparing an antibacterial thermoplastic polyurethane elastomer according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Mix thermoplastic polyurethane elastomer, ketone-aldehyde-amine condensate, silver ion antibacterial agent, antioxidant, and dispersant to obtain a mixed raw material; preferably, a mixer or kneader is used for mixing, more preferably a mixer, the mixer speed is 100-300 rpm, and the mixing time is 10s-10min; S2. The mixed raw materials are mixed evenly using one or more mixing devices, such as a single-screw extruder, a twin-screw extruder, an internal mixer, or an open mill, to obtain the antibacterial thermoplastic polyurethane elastomer; preferably, a twin-screw extruder is used, and the screw speed of the twin-screw extruder is 100-300 rpm.

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