Intrinsic antibacterial polyurethane pressure-sensitive adhesive and its preparation method

Abstract

This invention belongs to the field of polyurethane adhesive technology, specifically relating to an intrinsically antibacterial polyurethane pressure-sensitive adhesive and its preparation method. The preparation method includes: S1: reacting an antibacterial modified polyether polyol mixture, a first-stage isocyanate, and an antioxidant to obtain a hydroxyl-terminated polyether polyol; S2: then adding a chain extender, a metal-organic catalyst, and a second-stage isocyanate, and continuing the reaction until the NCO content is 0, thus obtaining the intrinsically antibacterial polyurethane pressure-sensitive adhesive; the antibacterial modified polyether polyol mixture is prepared by reacting a base polyether polyol with acrylic acid to obtain an unsaturated polyether polyol, followed by the addition of a solvent and an antibacterial agent, and then reacting under ultraviolet light. This invention aims to improve the antibacterial properties and adhesive strength of the material by introducing antibacterial groups, ester bonds, and other special functional groups into the molecular structure of the pressure-sensitive adhesive; simultaneously, through polymerization process design, the molecular weight of the pressure-sensitive adhesive is optimized, thereby enhancing its initial tack and cohesive force.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane adhesives, and in particular relates to an intrinsic antibacterial polyurethane pressure-sensitive adhesive and a preparation method thereof. Background Art

[0002] Polyurethane pressure-sensitive adhesives contain highly polar urethane groups (NHCOO), which easily form hydrogen bonds with each other, so they have excellent cohesion and adhesion. They can easily peel off the protected film, and no residual adhesive will be produced during the peeling process, nor will they cause pollution. By adjusting the molecular structure of polyols, polyurethane pressure-sensitive adhesives can be further given a variety of properties, such as moisture permeability, low allergenicity and easy cleaning. In recent years, polyurethane pressure-sensitive adhesives have received more and more attention from the industry and researchers.

[0003] Chinese patent CN116041635A discloses an antibacterial epoxy ester modified acrylic resin dispersion and preparation method, using the sulphur-ene "click" reaction to introduce quaternary ammonium salt groups into unsaturated fatty acids, and react with epoxy resin to prepare epoxy esters, and then use free radical polymerization to graft copolymerize acrylic monomers with epoxy esters to prepare antibacterial epoxy ester modified acrylic resin dispersions, but it is mainly used in the field of water-based anticorrosive coatings, and the preparation method is relatively cumbersome. Chinese patent CN114736619A discloses an easy-to-clean antibacterial tape and its preparation method, by adding nano antibacterial metal ion particles, such as nano silver, nano copper, nano aluminum, nano titanium particles, etc. to improve the antibacterial properties of pressure-sensitive adhesive materials. Chinese patent CN113122166A discloses a composite antibacterial pressure-sensitive adhesive composition, by adding nano antibacterial particles and traditional Chinese medicine antibacterial microspheres to improve the antibacterial properties of pressure-sensitive adhesive materials. However, both of the above patents achieve antibacterial effects by adding antibacterial ingredients, which may lead to problems such as uneven dispersion of antibacterial ingredients and poor long-term antibacterial stability of pressure-sensitive adhesives. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an intrinsically antibacterial polyurethane pressure-sensitive adhesive, which aims to improve the antibacterial properties and bonding strength of the material by introducing antibacterial groups, ester bonds and other special functional groups into the molecular structure of the pressure-sensitive adhesive; at the same time, through the design of the polymerization process, the control of the molecular weight of the pressure-sensitive adhesive is optimized, thereby enhancing its initial adhesion and cohesion.

[0005] Another object of the present invention is to provide a method for preparing an intrinsic antibacterial polyurethane pressure-sensitive adhesive, which has a simple process and is easy to mass produce.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive comprises the following steps:

[0008] S1: mixing the antibacterial modified polyether polyol mixture, the first stage isocyanate and the antioxidant for reaction for 2 hours to obtain a hydroxyl-terminated polyether polyol;

[0009] S2: Add a chain extender, a metal organic catalyst and a second isocyanate to the hydroxyl-terminated polyether polyol, and continue the reaction for 2 to 5 hours until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive;

[0010] In the step S1, the temperature of the mixed reaction is 90-100°C; in the step S2, the temperature of the continued reaction is 75-85°C.

[0011] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0012] (1) subjecting a base polyether polyol and acrylic acid to an esterification reaction under the action of an esterification catalyst to obtain an unsaturated polyether polyol;

[0013] (2) The unsaturated polyether polyol, solvent and antibacterial agent prepared in step (1) are put into a reaction kettle, and an antibacterial modified polyether polyol mixture is prepared by ultraviolet light irradiation reaction under the action of a modified catalyst.

[0014] In the step (1), the functionality of the basic polyether polyol is 3-6, and the number average molecular weight is 5000-12000 g / mol; the polymerization monomer of the basic polyether polyol is one or more of propylene oxide, ethylene oxide, epichlorohydrin or butylene oxide; and the molar ratio of the basic polyether polyol to acrylic acid is 1:(1-4).

[0015] In the step (2), the solvent is butyl acetate, and the amount of the solvent used is 8-13wt.% of the total amount of the antibacterial modified polyether polyol mixture; the antibacterial agent is N,N,N-trimethyl-(11-mercaptoundecyl)ammonium chloride or (3-mercaptopropyl)ammonium chloride, and the molar ratio of the antibacterial agent to the unsaturated polyether polyol is 1:(1-4).

[0016] In the step (1), the esterification catalyst is tetrabutyl titanate, and the temperature of the esterification reaction is 180-230°C; in the step (2), the modified catalyst is benzoin dimethyl ether or dimethyl azobisisobutyrate, the ultraviolet light wavelength is 360-400nm, and the ultraviolet light irradiance is 25mW / cm 2 .

[0017] The method for preparing the antibacterial modified polyether polyol mixture comprises introducing antibacterial groups into the molecular structure of the polyether polyol through a click reaction between the terminal hydroxyl polyether polyol prepared in step (1) and an antibacterial agent, and controlling the functionality of the obtained antibacterial modified polyether polyol mixture to be 2 by adjusting the molar ratio of the basic polyether polyol, acrylic acid and the antibacterial agent.

[0018] The isocyanate is IPDI or HDI with difunctionality; the molar ratio of the total amount of isocyanate in the isocyanate to the total amount of hydroxyl in the antibacterial modified polyether polyol mixture and the chain extender is (0.9-1.1):1;

[0019] In the step S1, the molar ratio of the hydroxyl group in the antibacterial modified polyether polyol mixture to the isocyanate group in the isocyanate is (1.9-2):1.

[0020] The antioxidant is Chic318A or Chic316A, purchased from Shanghai Chic Fluoro Silicone Material Co., Ltd.; the amount of the antioxidant is 0.1-0.2% of the total amount of the materials in steps S1 and S2.

[0021] The chain extender is one of INOVOL C202, INOVOL C204 or dodecyl bis(hydroxyethyl)methyl ammonium chloride, wherein INOVOL C202 and INOVOL C204 are purchased from Shandong Yinuowei New Materials Co., Ltd.; the mass ratio of the amount of the chain extender to the amount of the antibacterial modified polyether polyol mixture is 1:(39~57).

[0022] The metal organic catalyst is an organic bismuth catalyst, and the amount of the metal organic catalyst used is 0.05-0.1‰ of the total amount of materials in steps S1 and S2.

[0023] The intrinsic antibacterial polyurethane pressure-sensitive adhesive is prepared by adopting the above-mentioned preparation method of the intrinsic antibacterial polyurethane pressure-sensitive adhesive.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention modifies some hydroxyl groups of high-functional base polyether polyols through esterification and click reaction, and successfully introduces the quaternary ammonium salt antibacterial structure into the molecular skeleton of the polyol, thereby giving the pressure-sensitive adhesive material an intrinsic antibacterial ability. Compared with traditional additive antibacterial agents, the present invention fundamentally improves the antibacterial efficacy of the material, reduces the migration and failure risks of the antibacterial agent, and ensures the long-term and stable antibacterial effect of the pressure-sensitive adhesive product during use;

[0026] (2) The present invention introduces ester bonds into the molecular structure of the pressure-sensitive adhesive and achieves precise control of the molecular weight of the pressure-sensitive adhesive through a step-by-step polymerization process, thereby significantly improving the initial adhesion and cohesion of the pressure-sensitive adhesive material, ensuring that the pressure-sensitive adhesive can withstand greater shear force and peeling force during use and is less likely to break or fall off, thereby significantly extending the service life of the pressure-sensitive adhesive and enhancing the reliability and durability of the product. DETAILED DESCRIPTION

[0027] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0028] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0029] Some of the raw materials used in the examples and comparative examples are described as follows:

[0030] Polyether polyol INOVOL C350 (functionality 5, number average molecular weight 5000 g / mol) was purchased from Shandong INOVOL New Materials Co., Ltd.;

[0031] Polyether polyol INOVOL F628 (functionality 6, number average molecular weight 12000 g / mol) was purchased from Shandong INOVOL New Materials Co., Ltd.;

[0032] Polyether polyol INOVOL C202 (functionality 2, number average molecular weight 200 g / mol) was purchased from Shandong INOVOL New Materials Co., Ltd.;

[0033] Polyether polyol INOVOL C204 (functionality 2, number average molecular weight 400 g / mol) was purchased from Shandong INOVOL New Materials Co., Ltd.;

[0034] Tetrafunctional polyether A: 136g of pentaerythritol and 21g of potassium hydroxide catalyst were added to a high-pressure reactor, and the temperature was raised to 110°C after nitrogen replacement three times, and dehydrated for 6h. 8764g of propylene oxide was continuously added to the reactor, and the reaction temperature was controlled to be 110°C, and the pressure in the reactor was ≤0.3MPa. After the reaction was completed, it was aged for 4h, and the monomer was removed for 1h. After neutralization with acid water, drying, and adsorption refining treatment, the number average molecular weight was 8000g·mol -1 ;

[0035] Pentafunctional polyether B: 152 g of xylitol and 12.5 g of potassium hydroxide catalyst were added to a high-pressure reactor, and the temperature was raised to 110°C after nitrogen replacement three times, and dehydrated for 6 hours. 5282 g of propylene oxide was continuously added to the reactor, and the reaction temperature was controlled to be 110°C, and the pressure in the reactor was ≤0.3 MPa. After the reaction was completed, it was aged for 4 hours, and the monomer was removed for 1 hour. After neutralization with acid water, drying, and adsorption refining treatment, the number average molecular weight was 5000 g·mol -1 ;

[0036] Polyether polyol INOVOL C260 (functionality 2, number average molecular weight 6000 g / mol) was purchased from Shandong INOVOL New Materials Co., Ltd.;

[0037] Pentafunctional polyether D: 152 g xylitol and 10.9 g potassium hydroxide catalyst were added to a high-pressure reactor, and the temperature was raised to 110°C after nitrogen replacement three times, and dehydrated for 6 h. 4150 g propylene oxide was continuously added to the reactor, and the reaction temperature was controlled to be 110°C, and the pressure in the reactor was ≤0.3 MPa. After the reaction was completed, the polyether was aged for 4 h, and the monomer was removed for 1 h. The polyether was neutralized with acid water, dried, and purified by adsorption to obtain a polyether with a number average molecular weight of 4000 g·mol -1 .

[0038] Example 1

[0039] The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive comprises the following steps:

[0040] S1: 936.4 g (containing 0.2 mol of hydroxyl group) of antibacterial modified polyether polyol mixture, 8.4 g of HDI and 1.1 g of Chic316A were put into a reactor, heated to 95°C, and reacted for 2 h to obtain hydroxyl-terminated polyether polyol;

[0041] S2: Cooling to 85°C, adding 20g of INOVOL C202, 0.1g of bismuth isooctanoate and 25.2g of HDI to the hydroxyl-terminated polyether polyol, and continuing the reaction for 3h until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive;

[0042] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0043] (1) 800 g of tetrafunctional polyether A and 14.5 g of acrylic acid were subjected to esterification reaction at 230 °C under the catalysis of 8.2 g of tetrabutyl titanate, and small molecular substances were evaporated to obtain a molecular weight of 8109 g·mol -1 Unsaturated polyether polyols;

[0044] (2) 819.1 g of the unsaturated polyether polyol prepared in step (1), 87.8 g of butyl acetate and 25.5 g of (3-mercaptopropyl)ammonium chloride were placed in a reaction kettle and irradiated with a wavelength of 400 nm and an irradiance of 25 mW / cm2 in the presence of 4 g of benzoin dimethyl ether as a catalyst. 2 The antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction.

[0045] Example 2

[0046] The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive comprises the following steps:

[0047] S1: 1472.6 g (containing 0.2 mol hydroxyl group) of antibacterial modified polyether polyol mixture, 8.4 g of HDI and 1.8 g of Chic316A were put into a reactor, heated to 95°C, and reacted for 2 h to obtain hydroxyl-terminated polyether polyol;

[0048] S2: Cooling to 80°C, adding 30g of INOVOL C204, 0.15g of bismuth isooctanoate and 21g of HDI to the hydroxyl-terminated polyether polyol, and continuing the reaction for 5h until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive;

[0049] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0050] (1) 1200 g of INOVOL F628 and 28.8 g of acrylic acid were subjected to esterification reaction at 200 °C under the catalysis of 12.5 g of tetrabutyl titanate, and small molecular substances were evaporated to obtain a molecular weight of 12216 g·mol -1 Unsaturated polyether polyols;

[0051] (2) 1234.1 g of the unsaturated polyether polyol prepared in step (1), 180.5 g of butyl acetate and 51 g of (3-mercaptopropyl)ammonium chloride were placed in a reaction kettle and heated to 360 nm under the action of 7 g of dimethyl azobisisobutyrate as a catalyst at an irradiance of 25 mW / cm 2 The antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction.

[0052] Example 3

[0053] The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive comprises the following steps:

[0054] S1: 593.6 g (containing 0.2 mol hydroxyl group) of antibacterial modified polyether polyol mixture, 11.4 g of IPDI and 1 g of Chic318A were put into a reactor, heated to 100 °C, and reacted for 2 h to obtain hydroxyl-terminated polyether polyol;

[0055] S2: Cooling to 75°C, adding 15g of INOVOL C204, 0.05g of bismuth isooctanoate and 19.2g of IPDI to the hydroxyl-terminated polyether polyol, and continuing the reaction for 2h until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive;

[0056] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0057] (1) 500 g of INOVOL C350 and 7.2 g of acrylic acid were subjected to esterification reaction at 180 °C under the catalysis of 5.1 g of tetrabutyl titanate, and small molecular substances were evaporated to obtain a molecular weight of 5057 g·mol -1 Unsaturated polyether polyols;

[0058] (2) 510.5 g of the unsaturated polyether polyol prepared in step (1), 51.9 g of butyl acetate and 28.2 g of N,N,N-trimethyl-(11-mercaptoundecyl)ammonium chloride were added to a reaction kettle and heated to 300 nm under the action of 3 g of dimethyl azobisisobutyrate as a catalyst at an irradiance of 25 mW / cm 2 The antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction.

[0059] Example 4

[0060] The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive comprises the following steps:

[0061] S1: 680.8 g (containing 0.2 mol of hydroxyl group) of antibacterial modified polyether polyol mixture, 11.1 g of IPDI and 1.1 g of Chic316A were put into a reactor, heated to 90°C, and reacted for 2 h to obtain hydroxyl-terminated polyether polyol;

[0062] S2: Cooling to 80° C., adding 12 g of dodecyl bis(hydroxyethyl)methylammonium chloride, 0.05 g of bismuth isooctanoate and 19.32 g of IPDI to the hydroxy-terminated polyether polyol, and continuing the reaction for 2 h until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive;

[0063] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0064] (1) 500 g of pentafunctional polyether B and 21.6 g of acrylic acid were subjected to esterification reaction at 230 °C under the catalysis of 5.3 g of tetrabutyl titanate, and small molecular substances were evaporated to obtain a molecular weight of 5162 g·mol -1 Unsaturated polyether polyols;

[0065] (2) 521.5 g of the unsaturated polyether polyol prepared in step (1), 70.7 g of butyl acetate and 84.6 g of N,N,N-trimethyl-(11-mercaptoundecyl)ammonium chloride were added to a reaction kettle and heated at a wavelength of 380 nm and an irradiance of 25 mW / cm2 in the presence of 4 g of benzoin dimethyl ether as a catalyst. 2 The antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction.

[0066] Comparative Example 1

[0067] The difference from Example 4 is that a mixture of 600.8 g of INOVOL C260 and 70.7 g of butyl acetate is used to replace the antibacterial modified polyether polyol mixture, and the rest is the same as Example 1.

[0068] Comparative Example 2

[0069] The preparation method of the polyurethane pressure-sensitive adhesive comprises the following steps:

[0070] 680.8 g of antibacterial modified polyether polyol mixture, 30.42 g of IPDI, 1.1 g of Chic316A, 12 g of dodecyl bis(hydroxyethyl)methyl ammonium chloride and 0.05 g of bismuth isooctanoate were added into a reaction kettle, the temperature was raised to 90° C., and the reaction was carried out until the NCO content was 0, thereby obtaining a polyurethane pressure-sensitive adhesive;

[0071] Wherein, the preparation method of the antibacterial modified polyether polyol mixture has the same steps as Example 4.

[0072] Comparative Example 3

[0073] The preparation method of the polyurethane pressure-sensitive adhesive comprises the following steps:

[0074] S1: 568.69 g of antibacterial modified polyether polyol mixture, 11.1 g of IPDI and 1.1 g of Chic316A were put into a reactor, heated to 90° C., and reacted for 2 h to obtain hydroxyl-terminated polyether polyol;

[0075] S2: Cooling to 80° C., adding 12 g of dodecyl bis(hydroxyethyl)methylammonium chloride, 0.04 g of bismuth isooctanoate and 19.32 g of IPDI to the hydroxy-terminated polyether polyol, and continuing the reaction for 2 h until the NCO content is 0, thereby obtaining a polyurethane pressure-sensitive adhesive;

[0076] Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps:

[0077] (1) 400 g of pentafunctional polyether D and 21.6 g of acrylic acid were subjected to esterification reaction at 230° C. under the catalysis of 5 g of tetrabutyl titanate, and small molecular substances were evaporated to obtain unsaturated polyether polyol;

[0078] (2) The unsaturated polyether polyol prepared in step (1), 59.09 g of butyl acetate and 84.6 g of N,N,N-trimethyl-(11-mercaptoundecyl)ammonium chloride were placed in a reaction kettle, and the reaction mixture was heated to 380 nm under the action of 3.8 g of benzoin dimethyl ether as a catalyst at an irradiance of 25 mW / cm 2 The antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction.

[0079] The performance tests were performed on the pressure-sensitive adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 3, respectively, and the test methods were as follows:

[0080] Refer to GB / T 2792-2014 to test the peel force (N / cm);

[0081] Refer to GB / T 4852-2002 to test the initial adhesion and use the rolling ball method to test the maximum steel ball number that can be adhered;

[0082] Refer to GB / T 20944.1-2007 to test the inhibition zone of Staphylococcus aureus (mm) and the inhibition zone of Escherichia coli (mm);

[0083] The test results are shown in Table 1.

[0084] Table 1 Performance test results

[0085]

[0086] It can be seen from the test data in Table 1 that the antibacterial and mechanical properties of the pressure-sensitive adhesive prepared by the present invention have obvious advantages over those of Comparative Example 1. By comparing the data of Example 4 with that of Comparative Example 2, it can be found that the adjustment of the preparation steps will have a significant impact on the mechanical properties of the material. By comparing the data of Example 4 with that of Comparative Example 3, it can be found that the use of a basic polyether polyol with a lower molecular weight in the preparation of the antibacterial modified polyether polyol mixture will result in a decrease in the peeling force and initial tack of the final pressure-sensitive adhesive product.

Claims

1. A method for preparing an intrinsic antibacterial polyurethane pressure-sensitive adhesive, characterized in that: The following steps are involved: S1: mixing and reacting the antibacterial modified polyether polyol mixture, the first stage isocyanate and the antioxidant to obtain a hydroxyl-terminated polyether polyol; S2: adding a chain extender, a metal organic catalyst and a second stage isocyanate to the hydroxyl-terminated polyether polyol, and continuing the reaction until the NCO content is 0, thereby obtaining an intrinsic antibacterial polyurethane pressure-sensitive adhesive; Wherein, the preparation method of the antibacterial modified polyether polyol mixture comprises the following steps: (1) conducting an esterification reaction of a base polyether polyol having a number average molecular weight of 5000 to 12000 g / mol and acrylic acid in the presence of an esterification catalyst to obtain an unsaturated polyether polyol; (2) the unsaturated polyether polyol, solvent and antibacterial agent prepared in step (1) are put into a reaction kettle, and under the action of a modified catalyst, an antibacterial modified polyether polyol mixture is prepared by ultraviolet irradiation reaction; In the step (1), the functionality of the base polyether polyol is 3 to 6; In the step (2), the antibacterial agent is N,N,N-trimethyl-(11-mercaptoundecyl)ammonium chloride or (3-mercaptopropyl)ammonium chloride; In the step (2), the modified catalyst is benzoin dimethyl ether or dimethyl azobisisobutyrate, and the ultraviolet light wavelength is 360-400 nm.

2. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: In the step (1), the molar ratio of the base polyether polyol to the acrylic acid is 1:(1-4).

3. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: In the step (2), the solvent is butyl acetate, and the amount of the solvent used is 8-13wt.% of the total amount of the antibacterial modified polyether polyol mixture; the molar ratio of the antibacterial agent to the unsaturated polyether polyol is 1:(1-4).

4. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: In the step (1), the esterification catalyst is tetrabutyl titanate, and the temperature of the esterification reaction is 180-230°C.

5. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: The isocyanate is IPDI or HDI; the molar ratio of the total amount of isocyanate in the isocyanate to the total amount of hydroxyl in the antibacterial modified polyether polyol mixture and the chain extender is (0.9-1.1):1; In the step S1, the molar ratio of the hydroxyl group in the antibacterial modified polyether polyol mixture to the isocyanate group in the isocyanate is (1.9-2):

1.

6. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: The antioxidant is Chic318A or Chic316A, and the amount of the antioxidant is 0.1-0.2% of the total amount of the materials in steps S1 and S2.

7. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: The chain extender is one of INOVOL C204 and dodecyl bis(hydroxyethyl)methyl ammonium chloride, and the mass ratio of the amount of the chain extender to the amount of the antibacterial modified polyether polyol mixture is 1:(39-57).

8. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: The metal organic catalyst is an organic bismuth catalyst, and the amount of the metal organic catalyst used is 0.05-0.1‰ of the total amount of materials in steps S1 and S2.

9. The method for preparing the intrinsic antibacterial polyurethane pressure-sensitive adhesive according to claim 1, characterized in that: In the step S1, the temperature of the mixed reaction is 90-100°C; in the step S2, the temperature of the continued reaction is 75-85°C.

10. An intrinsically antibacterial polyurethane pressure-sensitive adhesive, characterized in that: The intrinsic antibacterial polyurethane pressure-sensitive adhesive is prepared by the preparation method of any one of claims 1 to 9.

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