Modified polyurethane and its preparation methods and applications, self-healing antibacterial photocurable coating compositions and their preparation methods and applications and products

Abstract

This invention relates to the field of organic photocuring technology, specifically to a modified polyurethane, its preparation method and application, a self-healing antibacterial photocurable coating composition, its preparation method, application, and products. The modified polyurethane of this invention has a macromolecular chain containing polyurethane segments, functional structural units, and acrylate end groups. The modified polyurethane provided by this invention contains a quaternary ammonium salt, which has good bactericidal properties and high stability. The synergistic effect of the imidazole ring and the quaternary ammonium salt enhances the antibacterial ability of the coating film, and the presence of the imidazole ring significantly improves the hardness of the coating film prepared from the modified polyurethane. Under external stimuli such as light, heat, or acid / alkali, the disulfide bonds can partially or completely restore the mechanical properties and integrity of the modified polyurethane itself, giving the modified polyurethane of this invention excellent self-healing properties, with a fracture self-healing rate of over 90%.

Description

Technical Field

[0001] This invention relates to the field of organic photocuring technology, specifically to a modified polyurethane and its preparation method and application, a self-healing antibacterial photocurable coating composition and its preparation method and application, and products. Background Technology

[0002] UV-cured coatings are widely used in the coating industry due to their advantages such as environmental friendliness, energy saving, high efficiency, and fast film formation rate. However, UV-cured coatings themselves do not have the ability to resist microbial or bacterial erosion. On the other hand, in actual use, coatings often develop microcracks, scratches, or even damage due to friction, collisions, etc. This weakens the dimensional stability and mechanical strength of the coating to varying degrees, and may even cause bacterial adhesion and proliferation at the damaged sites.

[0003] Antibacterial coatings can effectively inhibit the growth and spread of harmful bacteria or viruses, and their applications in daily life are becoming increasingly widespread, including wastewater purification systems, food and drug packaging and storage, daily necessities, household appliances and furniture, clothing and footwear, medical devices, and building materials. Compared with inorganic antibacterial agents and small-molecule organic antibacterial units, polymeric antibacterial units have advantages such as high functional group density, long-lasting antibacterial effect, low toxicity, low irritation to the human body, high chemical stability, no loss of antibacterial components, and no penetration into the skin of humans or animals.

[0004] Therefore, in order to extend the service life of coatings, the development of long-lasting, low-toxicity antibacterial coatings with self-healing functions is of great significance to production and daily life. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of environmental pollution, slow film formation speed, short service life, and poor antibacterial effect in the existing photocurable coating preparation process. This invention provides a modified polyurethane and its preparation method and application, a self-healing antibacterial photocurable coating composition and its preparation method and application, and products. The self-healing antibacterial photocurable coating prepared by this method has the advantages of environmentally friendly preparation process, fast film formation speed, long service life, good antibacterial effect, and self-healing.

[0006] To achieve the above objectives, the first aspect of the present invention provides a modified polyurethane, wherein the modified polyurethane has a macromolecular chain comprising polyurethane segments, functional structural units and acrylate end-capped groups; wherein the functional structural units comprise structural unit A having -SS- groups and structural unit B represented by formula (1).

[0007] R1 is a C1-C6 straight-chain or branched alkyl group, R2 and R3 are each independently structures represented by the general formula -O-Z1* or -NH-Z2*, and Z1 and Z2 are each independently C1-C6 straight-chain or branched alkylene groups.

[0008] R is a copolymer chain containing structural unit C shown in formula (2), structural unit D shown in formula (3), structural unit E shown in formula (4), and structural unit F from a monoolefin.

[0009]

[0010] R 1 R 3 Each is independently selected from C1-C6 straight-chain or branched alkylene groups, R 2 Selected from straight-chain or branched alkenyl groups, R 4 Selected from straight-chain or branched alkyl groups of -H or C1-C6, * indicates the position where it is connected to the N element in formula (1); X and Y are each independently selected from F, Cl, Br or I.

[0011] A second aspect of the present invention provides a method for preparing modified polyurethane, the method comprising:

[0012] (1) In the presence of a catalyst, polyisocyanate and oligomeric polyol are subjected to polycondensation reaction to generate a solution A containing polyurethane.

[0013] (2) The solution A, the intercalating copolymer, and the disulfide chain extender are copolymerized to obtain a polymer precursor; the intercalating copolymer contains structural unit C shown in formula (2), structural unit K shown in formula (6), structural unit E shown in formula (4), and structural unit F from a monoolefin.

[0014]

[0015] (3) The polymer precursor and the capping agent are subjected to a capping reaction to obtain modified polyurethane;

[0016] R1, R2, R3, R 1 R 2 R 3 R 4 The definition corresponds to the definition of modified polyurethane described in this invention.

[0017] A third aspect of the present invention provides a modified polyurethane prepared by the preparation method described in the present invention.

[0018] A fourth aspect of the present invention provides a self-healing antibacterial photocurable coating composition comprising the modified polyurethane described herein.

[0019] The fifth aspect of this invention provides the application of the modified polyurethane described herein in a self-healing antibacterial curing coating.

[0020] The sixth aspect of this invention provides a method for preparing a self-healing antibacterial photocurable coating, the method comprising the following steps:

[0021] (1) Mix the modified polyurethane, reactive diluent, and photoinitiator to obtain mixture A;

[0022] (2) Curing mixture A yields a self-healing antibacterial photocurable coating;

[0023] Wherein, the modified polyurethane is any one of the modified polyurethanes described in this invention.

[0024] The seventh aspect of the present invention provides a self-healing antibacterial photocurable coating film prepared by the preparation method described in the present invention.

[0025] The eighth aspect of the present invention provides an application of the self-healing antibacterial photocurable coating of the present invention in the surface coating of public goods.

[0026] The ninth aspect of the present invention provides an article having a self-healing antibacterial photocurable coating as described in the present invention on its surface.

[0027] Compared with the prior art, the advantages of the present invention are as follows:

[0028] The modified polyurethane provided by this invention contains quaternary ammonium salts, which have good bactericidal properties and high stability. The synergistic effect of the imidazole ring and the quaternary ammonium salt enhances the antibacterial ability of the coating film. The presence of the imidazole rings also enhances the wear resistance of the coating film and reduces the amount of polymer containing antibacterial components while achieving the desired antibacterial effect. This reduces the impact of the quaternary ammonium salt antibacterial unit on the water absorption of the coating film and increases the hydrolytic stability of the material. Under external stimuli such as light, heat, or acid and alkali, the disulfide bonds can partially or completely restore the mechanical properties and integrity of the modified polyurethane itself, giving the modified polyurethane of this invention good self-healing properties, with a fracture self-healing rate of over 90%.

[0029] Furthermore, the photocuring technology provided by this invention has outstanding advantages in preparing antibacterial polymer film coatings. This method has mild reaction conditions, fast reaction speed, and high efficiency, which helps to maintain the activity of antibacterial groups and avoids the disadvantages of loss of antibacterial activity caused by traditional thermal polymerization and its processing. It is green, environmentally friendly, and highly practical. Detailed Implementation

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] The first aspect of the present invention provides a modified polyurethane, wherein the modified polyurethane has a macromolecular chain comprising polyurethane segments, functional structural units and acrylate end-capped groups; wherein the functional structural units comprise structural unit A having -SS- groups and structural unit B represented by formula (1);

[0032] R1 is a C1-C6 straight-chain or branched alkyl group, R2 and R3 are each independently structures represented by the general formula -O-Z1* or -NH-Z2*, and Z1 and Z2 are each independently C1-C6 straight-chain or branched alkylene groups.

[0033] R is a copolymer chain containing structural unit C shown in formula (2), structural unit D shown in formula (3), structural unit E shown in formula (4), and structural unit F from a monoolefin.

[0034]

[0035] R 1 R 3 Each is independently selected from C1-C6 straight-chain or branched alkylene groups, R 2 Selected from C2-C6 straight-chain or branched alkenyl groups, R 4 Selected from straight-chain or branched alkyl groups of -H or C1-C6, * indicates the position where it is connected to the N element in formula (1); X and Y are each independently selected from F, Cl, Br or I.

[0036] The modified polyurethane provided by this invention contains quaternary ammonium salt, which has good bactericidal properties and high stability. The synergistic effect of the imidazole ring and the quaternary ammonium salt enhances the antibacterial ability of the coating film. Furthermore, the presence of the imidazole ring significantly improves the hardness of the coating film prepared by the modified polyurethane. Under external stimuli such as light, heat, or acid and alkali, the disulfide bonds can partially or completely restore the mechanical properties and integrity of the modified polyurethane itself, giving the modified polyurethane of this invention good self-healing properties, with a fracture self-healing rate of over 90%.

[0037] The modified polyurethane provided by this invention has a macromolecular chain structure in which structural unit A or structural unit B can be inserted between two adjacent polyurethane chain segments, and acrylate end capping groups are present at both ends of the entire modified polyurethane macromolecular chain. Wherein, as the functional structural unit, structural unit A can provide that the modified polyurethane macromolecular chain contains -SS- groups, and structural unit B can provide that the modified polyurethane macromolecular chain contains the structure shown in formula (1).

[0038] In this invention, the N element in structural unit B shown in formula (1) can connect the copolymer chain represented by R, thereby bringing good antibacterial properties and making the polymeric antibacterial units less prone to migration and loss to the macromolecular chain structure of the modified polyurethane.

[0039] In this invention, the two ends of the structural unit B can be respectively bonded to different polyurethane chain segments in the macromolecular chain structure of the modified polyurethane.

[0040] According to a particularly preferred embodiment of the present invention, R1 is -CH3 or -CH2CH3.

[0041] According to a particularly preferred embodiment of the present invention, Z1 and Z2 are each independently -CH2CH2- or -CH2CH2CH2-.

[0042] According to a particularly preferred embodiment of the present invention, R2 and R3 each independently have the structure shown in the general formula -O-Z1*.

[0043] According to a particularly preferred embodiment of the present invention, R2 and R3 are both -O-CH2CH2*.

[0044] According to a particularly preferred embodiment of the present invention, R 1 R 3 Each is independently selected from -CH2- or -CH2CH2-.

[0045] According to a particularly preferred embodiment of the present invention, R 2 For general formula R b -HC=CH-R a - The structure shown, R a Selected from -CH2- or -CH2CH2-, R b Selected from -H, -CH3 or -C2H5.

[0046] According to a particularly preferred embodiment of the present invention, R b Selected from -H.

[0047] According to a particularly preferred embodiment of the present invention, R 4 Selected from -CH3 or -C2H5.

[0048] According to a particularly preferred embodiment of the present invention, X and Y are each independently Cl or Br.

[0049] According to a particularly preferred embodiment of the present invention, the monoolefin is selected from isobutylene, isopentenene, isohexene, isoheptene, and isooctene.

[0050] According to a particularly preferred embodiment of the present invention, in the R of the structural unit B, the molar ratio of structural unit C to structural unit E is 1:(0.1-0.5).

[0051] According to a particularly preferred embodiment of the present invention, in the R of the structural unit B, the molar ratio of structural unit D to structural unit E is 1:(0.3-0.5).

[0052] According to a particularly preferred embodiment of the present invention, in the R of the structural unit B, the molar ratio of structural unit E to structural unit F is 1:(2-10).

[0053] According to a particularly preferred embodiment of the present invention, the weight-average molecular weight of the copolymer chain is 9000-15000 g / mol.

[0054] According to a particularly preferred embodiment of the present invention, the structural unit A has a general formula. The structures shown indicate that Z3, Z4, Z5, and Z6 are each independently a phenylene or a C1-C6 straight-chain or branched alkylene. Phenylidene compounds possess... The structure shown is such that 1 is connected to an SS bond and 2 is connected to an NH bond. The two ends of the above-described general formula of structural unit A can be bonded to different polyurethane chain segments within the macromolecular chain structure of the modified polyurethane.

[0055] According to a particularly preferred embodiment of the present invention, Z3 and Z4 are each independently -CH2CH2- or -C6H4-.

[0056] According to a particularly preferred embodiment of the present invention, the structural unit A has The structure shown. -NH- can be substituted at the para and meta positions of the benzene ring, preferably at the para position.

[0057] According to a particularly preferred embodiment of the present invention, in the functional structural unit, the molar ratio of structural unit A to structural unit B is (3-10):1.

[0058] According to a particularly preferred embodiment of the present invention, the acrylate end-capping group has the structure shown in formula (5).

[0059] R4 is selected from C1-C5 straight-chain or branched alkylene groups.

[0060] According to a particularly preferred embodiment of the present invention, R4 is selected from -CH2-, -CH2CH2-, and -CH2CH2CH2-.

[0061] According to a particularly preferred embodiment of the present invention, R5 is selected from -H or, C1-C3, straight-chain or branched alkyl groups.

[0062] According to a particularly preferred embodiment of the present invention, R5 is selected from -H or -CH3.

[0063] According to a particularly preferred embodiment of the present invention, the polyurethane segment contains structural units G derived from polyisocyanates and structural units H derived from oligomeric polyols.

[0064] According to a particularly preferred embodiment of the present invention, the polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. By employing the aforementioned preferred embodiment, the versatility and excellent adjustability of the modified polyurethane are improved.

[0065] According to a particularly preferred embodiment of the present invention, the oligomeric polyol is a polyether polyol, preferably selected from at least one of polypropylene glycol-2000, polypropylene glycol-3000, and polypropylene glycol-4000. By adopting the aforementioned preferred embodiment, the versatility and excellent adjustability of the modified polyurethane are improved.

[0066] According to a particularly preferred embodiment of the present invention, the weight-average molecular weight of the polyurethane segments is 3000-5000 g / mol.

[0067] According to a particularly preferred embodiment of the present invention, based on the total amount of the modified polyurethane, the molar ratio of the polyurethane segments, functional structural units and acrylate end-cap groups is 1:(1-1.2):(0.8-1).

[0068] According to a particularly preferred embodiment of the present invention, the modified polyurethane has a weight-average molecular weight of 9000-15000 g / mol and a viscosity of 200-400 mPa·s at 25°C.

[0069] According to a particularly preferred embodiment of the present invention, two adjacent polyurethane segments are connected by the functional structural unit, and the modified polyurethane has macromolecular chains with acrylate end-capping groups at the ends.

[0070] According to a particularly preferred embodiment of the present invention, the modified polyurethane has a macromolecular chain that further comprises a linking group of general formula -NHCO located between the polyurethane chain segment and the functional structural unit.

[0071] In this invention, the linking group can be generated by reacting the -NCO group at the original end of the polyurethane chain segment with the -OH or -NH group at the end of the functional structural unit.

[0072] A second aspect of the present invention provides a method for preparing modified polyurethane, the method comprising:

[0073] (1) In the presence of a catalyst, polyisocyanate and oligomeric polyol are subjected to polycondensation reaction to generate a solution A containing polyurethane.

[0074] (2) The solution A, the intercalating copolymer, and the disulfide chain extender are copolymerized to obtain a polymer precursor; the intercalating copolymer contains structural unit C shown in formula (2), structural unit K shown in formula (6), structural unit E shown in formula (4), and structural unit F from a monoolefin.

[0075]

[0076] (3) The polymer precursor and the capping agent are subjected to a capping reaction to obtain modified polyurethane;

[0077] Among them, R1, R2, R3, R 1 R 2 R 3 R 4 The definition corresponds to the definition described in the modified polyurethane of this invention.

[0078] In this invention, a disulfide chain extender and hydroxyl groups in the embedded copolymer react with -NCO bonds in the polyurethane precursor to achieve a link with the polyurethane. The resulting polymer precursor is then capped at the ends of the polyurethane chain segments by a capping agent, introducing the capping agent's groups to obtain the modified polyurethane.

[0079] The modified polyurethane prepared by the method of the present invention contains quaternary ammonium salt and imidazole salt copolymer as antibacterial components. These components are incorporated into the polyurethane main chain through polymerization via terminal hydroxyl groups, overcoming the problem of exudation or dissolution that easily occurs when adding blended antibacterial agents. In addition, the high molecular antibacterial units are not easily migrated or lost, and are safer and less toxic than small molecular organic antibacterial agents. Therefore, the modified polyurethane prepared has low toxicity and good antibacterial properties.

[0080] According to a particularly preferred embodiment of the present invention, the isocyanate requires pretreatment and isocyanate group content testing, both of which are performed using methods commonly used in the art.

[0081] According to a particularly preferred embodiment of the present invention, step (2) is started when the -NCO content in solution A decreases by 50 wt%.

[0082] According to a particularly preferred embodiment of the present invention, the endpoint of the end-capping reaction in step (3) is: when the -NCO content in the reaction system is less than or equal to 0.3%, the reaction is stopped and the resulting modified polyurethane needs to be cooled to room temperature before being discharged.

[0083] According to a particularly preferred embodiment of the present invention, the molar ratio of the polyisocyanate to the oligomeric polyol is (2-2.5):1.

[0084] According to a particularly preferred embodiment of the present invention, the amount of catalyst used is 0.05-0.1 wt% of the total weight of all raw materials.

[0085] According to a particularly preferred embodiment of the present invention, the disulfide bond extender is used in an amount of 1.5-2.5 wt% of the total weight of all raw materials.

[0086] According to a particularly preferred embodiment of the present invention, the amount of the embedded copolymer is 15-22 wt% of the total mass of all raw materials.

[0087] According to a particularly preferred embodiment of the present invention, the molar ratio of the capping agent to the polyisocyanate is 1:(2-2.5).

[0088] According to a particularly preferred embodiment of the present invention, the total amount of the feed is the sum of the feed amounts of the polyisocyanate, oligomeric polyol, intercalating copolymer, catalyst, disulfide chain extender and end capping agent.

[0089] In this invention, the range of types of polyisocyanates is relatively wide, and commonly used polyisocyanates can all be used in this invention. According to a particularly preferred embodiment of this invention, the polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

[0090] According to a particularly preferred embodiment of the present invention, the oligomeric polyol is selected from polyether polyols, preferably from at least one of polypropylene glycol-2000, polypropylene glycol-3000 and polypropylene glycol-4000, with a weight-average molecular weight of 2000-4000 g / mol.

[0091] In this invention, the range of disulfide bond chain extenders is relatively wide. According to one embodiment of this invention, the disulfide bond chain extender is selected from compounds having the general formula HO-Z3-SS-Z4-OH or H2N-Z5-SS-Z6-NH2, wherein Z3, Z4, Z5, and Z6 are each independently phenylene or C1-C6 straight-chain or branched alkylene, preferably Z3 and Z4 are each independently -CH2CH2- or -C6H4-.

[0092] According to a particularly preferred embodiment of the present invention, the disulfide chain extender is selected from at least one of bis(2-hydroxyethyl) disulfide, 4,4′-dithiodiphenylamine, and 2,2-dithiodiphenylamine. By employing the aforementioned preferred embodiment, the disulfide chain extender contains reversible covalent disulfide bonds, which, under external stimuli such as light, heat, or pH, can partially or completely restore the mechanical properties and integrity of the polymer itself, and theoretically can achieve an unlimited number of repair cycles.

[0093] In this invention, the range of types of capping agents is relatively wide, and commonly used capping agents can all be used in this invention, such as hydroxyl-functionalized acrylate capping agents. According to a preferred embodiment of this invention, the capping agent has the structure shown in formula (A5).

[0094] Wherein, R4 is selected from C1-C5 straight-chain or branched alkylene groups, preferably -CH2-, -CH2CH2-, or -CH2CH2CH2-; R5 is selected from -H or C1-C3 straight-chain or branched alkyl groups, preferably -H or -CH3.

[0095] According to a particularly preferred embodiment of the present invention, the capping agent is selected from at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate. The aforementioned preferred embodiment overcomes the problem of exudation or dissolution that easily occurs when adding blended antibacterial agents by polymerizing terminal hydroxyl groups to the end of the polyurethane macromolecular backbone.

[0096] In this invention, the range of catalysts that can be selected is relatively wide, and commonly used catalysts can all be used in this invention. In a particularly preferred embodiment of this invention, the catalyst is an organotin catalyst, preferably dibutyltin dilaurate and / or stannous octoate.

[0097] In this invention, the embedded copolymer can be a pre-prepared copolymer having the structural units C, K, E, and F. For example, it can be prepared by the following method:

[0098] (i) In the presence of an initiator system and a solvent, a monoolefin and monomer e, which provides structural unit E, are subjected to cationic polymerization to obtain a binary copolymer solution containing structural unit E and structural unit F.

[0099] (ii) The binary copolymer solution is washed with water and then subjected to a halogenation reaction to obtain a halogenated polymer;

[0100] (iii) The halogenated polymer is subjected to a salting reaction with an imidazole compound and a polyol amine to obtain the intercalated copolymer.

[0101] In (iii), imidazole compounds and polyol amines can be bonded to some of the halogenated groups in the halogenated polymer by their respective N elements through the salting reaction, thereby forming the structural unit C and structural unit K.

[0102] According to a particularly preferred embodiment of the present invention, the weight-average molecular weight of the embedded copolymer is 5000-8300 g / mol.

[0103] In this invention, the range of types of monoolefins is relatively wide, and commonly used monoolefins can be used in this invention. According to a particularly preferred embodiment of this invention, the monoolefin is selected from isobutylene, isopentenene, isohexene, isoheptene, and isooctene.

[0104] According to a particularly preferred embodiment of the present invention, the monoolefin is selected from isobutylene.

[0105] According to a particularly preferred embodiment of the invention, the amount of monomer e added satisfies the condition that, based on the total weight of the embedded copolymer, the mass fraction of structural unit E is 15-45%.

[0106] According to a particularly preferred embodiment of the present invention, the amount of imidazole compound and monomer e added satisfies the following condition: in the embedded copolymer, the molar ratio of structural unit C to structural unit E is 1:(0.1-0.5), for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, or any value within the range of any two of the above values.

[0107] According to a particularly preferred embodiment of the present invention, the amount of polyol amine and monomer e added satisfies the following condition: in the embedded copolymer, the molar ratio of structural unit K to structural unit E is 1:(0.3-0.5), for example, 1:0.3, 1:0.4, 1:0.5, or any value within the range of any two of the above values.

[0108] According to a particularly preferred embodiment of the present invention, the amount of monoolefin and monomer e added satisfies the following condition: in the embedded copolymer, the molar ratio of structural unit F to structural unit E is 1:(2-5), for example, 1:2, 1:3, 1:4, 1:5, or any value within the range of any two of the above values.

[0109] In a preferred embodiment of the present invention, the imidazole compound is selected from vinylimidazole and / or allylimidazole.

[0110] The polyol amine is selected from N-methyldiethanolamine and / or N-methyldipropanolamine.

[0111] The monomer e is selected from one of p-methylstyrene, p-ethylstyrene, and p-isobutylstyrene.

[0112] In a particularly preferred embodiment of the present invention, the imidazole compound is allyl imidazole, the polyol amine is N-methyldiethanolamine, the monomer e is p-methylstyrene, the monoolefin is isobutylene, and the halogenation reaction is a bromination reaction, but the present invention is not limited thereto.

[0113] The initiator system described in (i) is not particularly limited, as long as it can promote the cationic polymerization reaction of the monoolefin and monomer e. For example, the initiator system may contain a proton-donating compound (e.g., HCl), at least one Lewis acid (dichloroethylaluminum, diethylaluminum chloride), and at least one activator (e.g., tetrahydrobenzoquinone, tetrachlorobenzoquinone, tetracyanobenzoquinone, and dichlorodicyanobenzoquinone). In this invention, hydrogen chloride / dichloroethylaluminum / tetrachlorobenzoquinone is used as the initiator system (molar concentration ratio of 1:10:1) to illustrate the advantages of the invention, but the invention is not limited thereto. The solvent can be alkanes and haloalkanes. Hexane / dichloromethane (60 / 40, V / V) is used as an example to illustrate the advantages of this invention, but the invention is not limited thereto. There are no special restrictions on the amount of solvent and initiator in the initiator system; those skilled in the art can choose according to their needs, which will not be elaborated here. The cationic polymerization reaction conditions include: a temperature of -60℃ to -20℃, preparation of a low-molecular-weight, fully saturated binary copolymer containing structural units D and E, and the polymerization reaction being carried out between monomer e and the olefin carbon-carbon double bond in the monoolefin. Monomer e provides the structural unit E.

[0114] (ii) The binary copolymer undergoes a halogenation reaction with a halogen, wherein the halogenation reaction conditions include: washing the binary copolymer solution with water, then performing a pulsed (10s) photobromination reaction at room temperature using a 595nm light source with slow dropwise addition of liquid bromine, for a bromination reaction time of 60-150 min; subsequently, the brominated polymer solution is washed with water and centrifuged to obtain the halogenated polymer. This can allow some structural unit E to contain R... 4 Halogens are substituted to form halogenated side groups in the macromolecular chains of the binary copolymer.

[0115] The conditions for the salting reaction described in (iii) include: a reaction temperature of 50-80℃; specifically, first, a polyol amine compound is added dropwise, and after reacting for 10-24 hours, an imidazole compound is added to the reaction system and the reaction continues for another 10-24 hours; after the salting reaction is completed, a certain amount of anhydrous diethyl ether is added to the system, resulting in the precipitation of a large amount of solid. After filtration, washing, and drying, the intercalation copolymer is obtained. The imidazole compound and the polyol amine react with the halogenated side groups through their respective nitrogen elements to form the structural units C and K in the intercalation copolymer.

[0116] In this invention, the structural unit K, through the hydroxyl group introduced by the polyol amine, can react with the isocyanate group contained in the polyurethane contained in the solution A during the copolymerization reaction in step (2) to form a -NHCO- connection.

[0117] In this invention, the disulfide chain extender, through the presence of hydroxyl or amino groups, reacts with the isocyanate groups contained in the polyurethane in solution A during the copolymerization process in step (2) to form a -NHCO- linkage.

[0118] In this invention, through the copolymerization reaction in step (2), the embedded copolymer and the disulfide bond extender are respectively incorporated into the macromolecular chain of polyurethane.

[0119] According to a particularly preferred embodiment of the present invention, the conditions for the polycondensation reaction include: reaction time: 1-2 h, reaction temperature: 60-70 °C.

[0120] According to a particularly preferred embodiment of the present invention, the conditions for the copolymerization reaction include: reaction time: 2-4 h, reaction temperature: 70-80 °C.

[0121] According to a particularly preferred embodiment of the present invention, the conditions for the end-capping reaction include: reaction time: 1-2 h, reaction temperature: 80-85 °C. The terminal hydroxyl groups contained in the end-capping agent react with the isocyanate terminal groups in the polymer precursor to form -NHCO- groups, thereby converting the isocyanate terminal groups into end groups provided by the end-capping agent, overcoming the problem of exudation or dissolution that easily occurs when adding blended antibacterial agents.

[0122] A third aspect of the present invention provides a modified polyurethane prepared by the preparation method described in the present invention.

[0123] The modified polyurethane prepared by this invention uses quaternary ammonium salt and imidazole salt copolymer as antibacterial component. The high molecular antibacterial unit is not easy to migrate and lose. Compared with small molecular organic antibacterial agents, it is safer and less toxic. The prepared modified polyurethane has strong antibacterial properties, good mechanical properties and stability.

[0124] A fourth aspect of the present invention provides a self-healing antibacterial photocurable coating composition comprising the modified polyurethane described herein.

[0125] This invention provides a self-healing antibacterial curing coating containing the polymer described in this invention, which can improve the antibacterial properties, mechanical properties, and self-healing properties of the self-healing antibacterial curing coating.

[0126] According to a particularly preferred embodiment of the present invention, the composition further comprises an active diluent and a photoinitiator.

[0127] According to a particularly preferred embodiment of the present invention, the composition comprises, by weight, 35-45 parts of modified polyurethane, 52-60 parts of reactive diluent, and 3-5 parts of photoinitiator.

[0128] The fifth aspect of this invention provides the application of the modified polyurethane described herein in a self-healing antibacterial curing coating.

[0129] By applying the modified polyurethane prepared in this invention to a self-healing antibacterial curing coating, the antibacterial properties, mechanical properties, and self-healing properties of the coating can be improved.

[0130] The sixth aspect of this invention provides a method for preparing a self-healing antibacterial photocurable coating, the method comprising the following steps:

[0131] (1) Mix the modified polyurethane, reactive diluent, and photoinitiator to obtain mixture A;

[0132] (2) Curing mixture A yields a self-healing antibacterial photocurable coating;

[0133] The modified polyurethane is the modified polyurethane described in this invention.

[0134] In this invention, the range of types of reactive diluents is relatively wide, and commonly used types can be used. According to a particularly preferred embodiment of this invention, the reactive diluent is selected from at least one of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate, and isobornyl acrylate. By adopting the aforementioned preferred method, the multiple active functional groups of the reactive diluent can participate in the reaction, which not only improves the curing rate of the photocurable coating but also enhances the overall performance of the material.

[0135] According to a particularly preferred embodiment of the present invention, the reactive diluent is selected from tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, and isobornyl acrylate.

[0136] According to a particularly preferred embodiment of the present invention, the mass ratio of tripropylene glycol diacrylate: 1,6-hexanediol diacrylate: isobornyl acrylate is (15-17):(10-15):(25-30). By adopting the aforementioned preferred embodiment, since the reactive diluent has multiple active functional groups that can participate in the reaction, the curing rate of the photocurable coating is further improved, and the overall performance of the material is enhanced.

[0137] According to a particularly preferred embodiment of the present invention, the photoinitiator is selected from at least one of 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide. By adopting the aforementioned preferred embodiment, the absorption spectrum of the photoinitiator matches the emission spectrum of the radiation source, which can efficiently induce chemical reactions between unsaturated double bonds in the system and improve the photoinitiation efficiency.

[0138] According to a particularly preferred embodiment of the present invention, the photoinitiator is selected from 2-hydroxy-2-methyl-1-phenylpropanone.

[0139] According to a particularly preferred embodiment of the present invention, the mixing conditions include: a temperature of 30-60°C and a time of 2-5 hours.

[0140] According to a particularly preferred embodiment of the present invention, the curing conditions include: a temperature of 20-30°C and a time of 1-10 minutes.

[0141] According to a particularly preferred embodiment of the present invention, the curing machine has a power of 1000-1500W, a main emission wavelength of 365nm and 385nm, and an irradiation distance of 20-25cm.

[0142] According to a particularly preferred embodiment of the present invention, the modified polyurethane comprises 35-45 parts, the reactive diluent 52-60 parts, and the photoinitiator 3-5 parts.

[0143] According to a particularly preferred embodiment of the present invention, mixture A is allowed to stand to degas, and then uniformly coated onto a tin-plated tinplate sheet using a wire bar coater. The thickness of the cured layer is controlled to be 0.2-0.5 mm. After being placed in an ultraviolet curing machine for light curing, a self-healing antibacterial light-cured coating film is obtained.

[0144] The seventh aspect of the present invention provides a self-healing antibacterial photocurable coating film prepared by the preparation method described in the present invention.

[0145] The photocuring technology provided by this invention has outstanding advantages in the preparation of antibacterial polymer film coatings. The method has mild reaction conditions, fast reaction speed, and high efficiency, which helps to maintain the activity of antibacterial groups and avoids the disadvantages of loss of antibacterial activity caused by traditional thermal polymerization and its processing. It is green, environmentally friendly, and highly practical.

[0146] The eighth aspect of the present invention provides an application of the self-healing antibacterial photocurable coating of the present invention in the surface coating of public goods.

[0147] The ninth aspect of the present invention provides an article having a self-healing antibacterial photocurable coating as described in the present invention on its surface.

[0148] Self-healing efficiency: The sample was divided into two parts. One part was cut in half with scissors, and the two pieces were tightly bonded together and placed in a 50℃ oven for 2 hours. The other part was the original sample without any treatment. The tensile strength of the repaired sample and the original sample were tested after 2 hours, and their self-healing efficiency was calculated. The self-healing efficiency H is the ratio of the tensile strength of the repaired sample to the tensile strength of the original sample.

[0149] Antibacterial performance test: The antibacterial effect of the antibacterial coating was tested according to ISO 22196 standard. The experimental subject was Gram-negative bacteria Escherichia coli. The plate count method was used to characterize the antibacterial rate of the coating against Escherichia coli at different times. The entire process was carried out under aseptic conditions.

[0150] Water absorption rate: Cut the membrane into 25mm×25mm thin sheets, dry them in an oven at 60℃ for 24 hours, and weigh them as W1. Then place the dried sheets in 50mL of deionized water for 24 hours, absorb the unabsorbed water on the surface, and weigh them as W2. The water absorption rate is calculated as (W2-W1 / W1)×100%.

[0151] Method for determining polymer molecular weight: The molecular weight was determined using an LC-20A gel permeation chromatograph with tetrahydrofuran as solvent, a sample concentration of 20 mg / 10 mL, an injection volume of 100 μl, and a flow rate of 1.0 mL / min. The calibration curve was determined using PS as a standard.

[0152] Viscosity testing method: Use a digital rotational viscometer, select a suitable rotor, and measure the viscosity of the sample at various temperatures. The resin must be able to completely cover the rotor.

[0153] Pencil hardness test: According to the national standard GB / T6739-2006, the pencil hardness grades used are 2B, B, HB, H, and 2H to 6H. The test begins with a 6H pencil. Each pencil is tested 5 times on the coating film, rotating between pencils of different hardnesses, until only one of the five marks found scratches the coating film and leaves a mark on the substrate. The next lower pencil hardness grade represents the hardness of the cured film.

[0154] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and should not be considered as limiting the scope of the present invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise stated, all raw materials involved in the embodiments are commercially available products. The composition and structure of the obtained polymer are determined by the amount of raw materials fed.

[0155] Preparation Example

[0156] Used to illustrate the preparation of embedded copolymers:

[0157] Using hydrogen chloride / dichloroethylaluminum / tetrachlorobenzoquinone (molar concentration ratio of 1:1:1) as the initiating system and hexane / dichloromethane (60 / 40, V / V) as the solvent, isobutylene and p-methylstyrene were subjected to cationic polymerization in the range of -60℃ to -20℃ to obtain an isobutylene-p-methylstyrene copolymer solution.

[0158] After washing the isobutylene-p-methylstyrene copolymer solution with water, the isobutylene-p-methylstyrene copolymer solution was subjected to photobromination reaction by slowly adding liquid bromine at room temperature and under irradiation conditions of 595nm light source pulse (10s). The bromination reaction time was 60-150min. The product was washed with water and centrifuged to obtain the brominated polymer.

[0159] N-methyldiethanolamine was reacted with a brominated polymer at 50-80°C for 10-24 hours. Then, allyl imidazole was added to the reaction system, and the reaction continued for another 10-24 hours. After the reaction was complete, a certain amount of anhydrous diethyl ether was added to the system, resulting in the precipitation of a large amount of solid. This solid was filtered, washed, and dried to obtain the intercalated copolymer, the schematic structure of which is shown below:

[0160]

[0161] By adjusting the conditions and the amount of raw materials added, we obtained the following results:

[0162] Intercalated copolymer I: weight average molecular weight is 8000 g / mol, without structural unit C shown in formula (2) (i.e., no allyl imidazole is added during preparation, and the preparation conditions are the same as those for preparing intercalated copolymer IV), the mass fraction of structural unit E is 30%, the molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.3, and the molar ratio of structural unit F to structural unit E shown in formula (4) is 1:5;

[0163] Embedded copolymer II: weight average molecular weight is 5000 g / mol, mass fraction of structural unit E is 30%, the molar ratio of structural unit C shown in formula (2) to structural unit E shown in formula (4) is 1:0.2, the molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.4, and the molar ratio of structural unit F to structural unit E shown in formula (4) is 1:2;

[0164] Embedded copolymer III: weight average molecular weight is 5200 g / mol, mass fraction of structural unit E is 30%, the molar ratio of structural unit C shown in formula (2) to structural unit E shown in formula (4) is 1:0.1, the molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.4, and the molar ratio of structural unit F to structural unit E shown in formula (4) is 1:2;

[0165] Intercalated copolymer IV: weight average molecular weight is 8200 g / mol, mass fraction of structural unit E is 30%, the molar ratio of structural unit C shown in formula (2) to structural unit E shown in formula (4) is 1:0.5, the molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.3, and the molar ratio of structural unit F to structural unit E shown in formula (4) is 1:5.

[0166] The embedded copolymer V has a weight-average molecular weight of 8300 g / mol, a mass fraction of 30% for structural unit E, a molar ratio of 1.5:0.5 for structural unit C shown in formula (2) and 1:0.3 for structural unit K shown in formula (6) and 1:5 for structural unit E shown in formula (4), and a molar ratio of 1:5 for structural unit F and 1:5 for structural unit E shown in formula (4).

[0167] Example 1

[0168] A thermometer and a constant-pressure dropping funnel were set up in a three-necked flask, and 4.44 g of pretreated isophorone diisocyanate was added. Then, 0.03 g of dibutyltin dilaurate (catalyst) was added and stirred until homogeneous. 30.06 g of oligopropylene glycol PPG3000 was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 1 hour, producing a polyurethane-containing solution A with a weight-average molecular weight of 4000 g / mol. Samples were continuously taken during the reaction, and the isocyanate group content in the system was determined.

[0169] When the isocyanate group content was reduced to half of its original value, 6.96 g of intercalation copolymer II and 0.69 g of bis(2-hydroxyethyl) disulfide (disulfide bond chain extender) were added sequentially to solution A containing polyurethane. The temperature was raised to 85°C and the reaction was continued for 1 hour. Finally, 1.04 g of hydroxyethyl methacrylate was added dropwise for end-capping, and the reaction was carried out at 80°C for 1 hour. During the reaction, samples were continuously taken and the isocyanate group content in the system was measured. The reaction was terminated when the content was lower than 0.3%. The solution was cooled to room temperature and discharged. The resulting viscous liquid was the modified polyurethane A1, with a weight-average molecular weight of 9200 g / mol and a viscosity of 260 mPa·s at 25°C.

[0170] Example 2

[0171] A thermometer and a constant-pressure dropping funnel were set up in a three-necked flask, and 4.44 g of pretreated isophorone diisocyanate was added. Then, 0.03 g of dibutyltin dilaurate (catalyst) was added and stirred until homogeneous. 30.06 g of oligopropylene glycol PPG3000 was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 1 hour, producing a polyurethane-containing solution A with a weight-average molecular weight of 4000 g / mol. Samples were continuously taken during the reaction, and the isocyanate group content in the system was measured.

[0172] When the isocyanate group content was reduced to half of its original value, 6.96 g of intercalation copolymer III and 0.69 g of bis(2-hydroxyethyl) disulfide were added sequentially to solution A containing polyurethane. The temperature was raised to 85 °C and the reaction was continued for 1 h. Finally, 1.04 g of hydroxyethyl methacrylate was added dropwise for end-capping, and the reaction was carried out at 80 °C for 1 h. During the reaction, samples were continuously taken and the isocyanate group content in the system was measured. The reaction was terminated when the content was lower than 0.3%. The solution was cooled to room temperature and discharged. The resulting viscous liquid was modified polyurethane A2, with a weight-average molecular weight of 9500 g / mol and a viscosity of 280 mPa·s at 25 °C.

[0173] Example 3

[0174] A thermometer and a constant-pressure dropping funnel were set up in a three-necked flask, and 4.01 g of pretreated toluene diisocyanate was added. Then, 0.02 g of dibutyltin dilaurate (catalyst) was added and stirred until homogeneous. 20.01 g of oligomeric propylene glycol (PPG2000) was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 1 hour, producing a polyurethane-containing solution A with a weight-average molecular weight of 3600 g / mol. Samples were continuously taken during the reaction, and the isocyanate group content in the system was determined.

[0175] When the isocyanate group content was reduced to half of its original value, 5.18 g of intercalation copolymer IV and 0.77 g of bis(2-hydroxyethyl) disulfide were added to solution A containing polyurethane. The temperature was raised to 80 °C and the reaction was continued for 1 hour. Finally, 1.04 g of hydroxyethyl acrylate was added dropwise for end-capping, and the reaction was continued at 80 °C for 1 hour. During the reaction, samples were continuously taken and the isocyanate group content in the system was measured. The reaction was terminated when the content was lower than 0.3%. The solution was cooled to room temperature and discharged. The resulting viscous liquid was modified polyurethane A3, with a weight-average molecular weight of 13700 g / mol and a viscosity of 360 mPa / s at 25 °C.

[0176] Example 4

[0177] A thermometer and a constant-pressure dropping funnel were set up in a three-necked flask, and 4.01 g of pretreated toluene diisocyanate was added. Then, 0.02 g of dibutyltin dilaurate (catalyst) was added and stirred until homogeneous. 20.01 g of oligomeric propylene glycol (PPG2000) was slowly added dropwise. After the addition was complete, the temperature was raised to 60 °C and the reaction was carried out for 1 hour, producing a polyurethane-containing solution A with a weight-average molecular weight of 3600 g / mol. Samples were continuously taken during the reaction, and the isocyanate group content in the system was determined.

[0178] When the isocyanate group content was reduced to half of its original value, 5.18 g of intercalation copolymer V and 0.77 g of bis(2-hydroxyethyl) disulfide were added to solution A containing polyurethane. The temperature was raised to 80 °C and the reaction was continued for 1 hour. Finally, 1.04 g of hydroxyethyl acrylate was added dropwise for end-capping, and the reaction was continued at 80 °C for 1 hour. During the reaction, samples were continuously taken and the isocyanate group content in the system was measured. The reaction was terminated when the content was lower than 0.3%. The solution was cooled to room temperature and discharged. The resulting viscous liquid was modified polyurethane A4, with a weight-average molecular weight of 14200 g / mol and a viscosity of 400 mPa·s at 25 °C.

[0179] Comparative Example 1

[0180] Similar to Example 1, except that the intercalating copolymer II was not added, and other conditions remained unchanged, resulting in a viscous liquid, which is the modified polyurethane D1, with a weight-average molecular weight of 4300 g / mol and a viscosity of 120 mPa·s at 25°C.

[0181] Comparative Example 2

[0182] Similar to Example 1, except that bis(2-hydroxyethyl) disulfide was not added, and other conditions remained unchanged, resulting in a viscous liquid, which is the modified polyurethane D2, with a weight-average molecular weight of 9000 g / mol and a viscosity of 260 mPa·s at 25°C.

[0183] Comparative Example 3

[0184] Similar to Example 3, except that intercalating copolymer I was added instead of intercalating copolymer IV. The resulting viscous liquid is the modified polyurethane D3, with a weight-average molecular weight of 8700 g / mol and a viscosity of 230 mPa·s at 25°C.

[0185] Preparation Examples 1-11

[0186] Weigh all raw materials according to the proportions in Table 1 by weight. Add the synthesized modified polyurethane, reactive diluent, and photoinitiator to separate containers. Stir magnetically under light-protected conditions until uniformly mixed. The mixing temperature is 50℃ and the time is 3 hours to obtain mixture A. Then, use a wire rod coater to evenly coat the mixture onto a tin-plated tinplate sheet, controlling the cured layer thickness to 0.3 mm. Place the mixture in a UV curing machine (1200W power, main emission wavelengths of 365nm and 385nm, irradiation distance of 22cm, temperature of 25℃, and time of 4 minutes) for UV curing to obtain a UV-cured coating film. Prepare the UV-cured coating film according to the formula shown in Table 1.

[0187] Table 1

[0188]

[0189] Test case

[0190] The properties of the photocurable coatings prepared in Examples 1-11 were tested, and the results are shown in Table 2.

[0191] Table 2

[0192]

[0193] As can be seen from Table 2, the photocurable coatings provided in Preparation Examples 1-7 and 9-11 of the present invention contain reversible covalent disulfide bonds, and are repairable under external stimuli such as heating. The self-repair rate of fracture after 2 hours is greater than 85%, and can reach up to 98.8%. In contrast, Preparation Example 8 does not contain reversible covalent disulfide bonds, and the self-repair rate of fracture after 2 hours is only 26.8%.

[0194] Furthermore, using an imidazole / quaternized isobutylene / p-methylstyrene copolymer as the antibacterial component, which is polymerized into the polyurethane resin backbone via terminal hydroxyl groups, overcomes the problem of exudation or dissolution that easily occurs with blended antibacterial agents. This effectively protects the bactericidal units and provides better bactericidal performance. For example, the coatings prepared in Preparation Examples 1-6, 8, 10, and 11 all showed an anti-Escherichia coli rate greater than 92% after 3 hours of contact. In contrast, without the addition of the intercalating copolymer (Preparation Example 7), the anti-Escherichia coli rate of the prepared coating was only 16.5% and 13.1% after 1 and 3 hours of contact, respectively, indicating no antibacterial activity. As shown in Preparation Examples 4 and 11, when the mass fraction of p-methylstyrene in the antibacterial copolymer and the molar proportion of the antibacterial component derived from the p-methylstyrene structural units in the copolymer are the same, the coating containing the imidazole unit exhibits slightly stronger antibacterial properties. Because quaternary ammonium salts are broad-spectrum antibacterial agents, and imidazole rings are structural units with antibacterial properties, they can have a synergistic effect in antibacterial properties, thereby improving the antibacterial properties of the coating film.

[0195] A comparison of Preparation Examples 2, 3, 5, and 6 shows that within the optimal range of raw material proportions, a higher content of antibacterial components results in a stronger antibacterial effect. However, with further increases in the amount of antibacterial components (Preparation Examples 5 and 10), the antibacterial activity does not change significantly. Therefore, from the perspective of saving raw materials, the addition of antibacterial agents should be controlled within a certain range. Simultaneously, the presence of the imidazole ring significantly improves the hardness of the coating film. For example, the coating film containing imidazole units (Preparation Example 3) has a hardness of 2H, while the coating film in Preparation Example 11 has a hardness of only HB, indicating a difference in hardness. As shown in Preparation Examples 1, 2, 4, and 5, under the same conditions, with an increase in the content of imidazole ring units, the pencil hardness of the coating film gradually increases, which is beneficial for increasing the wear resistance of the coating film.

[0196] The water absorption rate of the coating film was determined to ascertain its water absorption and hydrolytic stability. Within the optimal range of raw material ratios, the coating film without quaternary ammonium salt antibacterial units exhibited a certain degree of hydrophobicity and was not easily dissolved by water absorption. Generally, the water absorption rate increased with the gradual increase of the quaternary ammonium salt component, which is a result of the easy binding of water by the quaternary ammonium salt cations. However, since the antibacterial units contain hydrophobic benzene ring structures and hydrophobic alkyl chains, their overall impact on the water absorption rate of the coating film was not significant, and the water absorption rate was less than 2.3%. If the content of the antibacterial polyurethane component was too high (Preparation Example 10), the water absorption rate increased to 3.5, affecting the hydrolytic stability of the coating material.

[0197] Furthermore, as can be seen from the results of the examples and comparative examples, the presence of the imidazole-containing structural unit C in the modified polyurethane of the present invention enhances the wear resistance of the coating film on the one hand, and reduces the amount of polymer containing antibacterial components while achieving the ideal antibacterial effect on the other hand, thereby reducing the impact of the quaternary ammonium salt antibacterial unit on the water absorption of the coating film and increasing the hydrolytic stability of the material.

[0198] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A modified polyurethane, characterized in that, The macromolecular chain of the modified polyurethane comprises a polyurethane segment, a functional structure unit and an acrylate end-capping group; wherein the functional structure unit comprises a structure unit A with a-S-S- group and a structure unit B shown in formula (1); Formula (1), wherein R1is a C1-C6linear or branched alkyl group, R2, R3are each independently a structure represented by general formula -O-Z1*or -NH-Z2*, wherein Z1, Z2are each independently a C1-C6linear or branched alkylene group, R is a copolymer chain comprising a structure unit C shown in formula (2), a structure unit D shown in formula (3), a structure unit E shown in formula (4) and a structure unit F from a mono-olefin, Formula (2), Formula (3), Formula (4), wherein R 1 , R 3 are each independently selected from a C1-C6 linear or branched alkylene group, R 2 is selected from a C2-C6 linear or branched alkenyl group, R 4 is selected from -H or a C1-C6 linear or branched alkyl group, and * is the position of attachment to the N element in formula (1); X, Y are each independently selected from F, Cl, Br, or I; In the R of the structure unit B, The molar ratio of the structure unit C to the structure unit E is 1:(0.1-0.5); The molar ratio of the structure unit D to the structure unit E is 1:(0.3-0.5); The molar ratio of the structure unit F to the structure unit E is 1:(2-5); The molar ratio of the polyurethane segment, the functional structure unit and the acrylate end-capping group is 1:(1-1.2):(0.8-1) based on the total amount of the modified polyurethane; The weight average molecular weight of the modified polyurethane is 9000-15000 g / mol; The weight average molecular weight of the polyurethane segment is 3000-5000 g / mol.

2. The modified polyurethane of claim 1, wherein, R1 is -CH3 or -CH2CH3; And / or, Z1, Z2 are each independently -CH2CH2- or -CH2CH2CH2-; and / or, R 1 , R 3 are each independently selected from -CH2- or -CH2CH2-; and / or, R 2 is of the structure shown in formula R b -HC=CH-R a -CH2-CH2-R a is blank or selected from -CH2- or -CH2CH2-, R b is selected from -H, -CH3, or -C2H5; and / or, R 4 is selected from -CH3or -C2H5; And / or, X, Y are each independently Cl or Br; And / or, the mono-olefin is selected from one of isobutylene, isoamylene, isohexene, isoheptene and isooctene.

3. The modified polyurethane of claim 2, wherein, R2, R3 are each independently a structure shown in general formula -O-Z1*; and / or, R b is -H.

4. The modified polyurethane of claim 3, wherein, R2, R3 are both -O-CH2CH2*.

5. The modified polyurethane of any of claims 1-3, wherein, The structural unit A has the general formula or as shown, wherein Z3, Z4, Z5, Z6 are each independently phenylene or a C1-C6 straight-chain or branched alkylene group.

6. The modified polyurethane of claim 5, wherein, Z3, Z4 are each independently -CH2CH2- or -C6H4-.

7. The modified polyurethane of claim 5, wherein, The structural unit A has or the structure shown.

8. The modified polyurethane of any of claims 1-3, wherein, In the functional structure unit, the molar ratio of the structure unit A to the structure unit B is (3-10):

1.

9. The modified polyurethane of any of claims 1-3, wherein, The acrylate end-capping group has a structure shown in formula (5), Formula (5), wherein R4 is selected from C1-C5 straight or branched chain alkylene; And / or, R5 is selected from -H or C1-C3 linear or branched alkyl.

10. The modified polyurethane of claim 9, wherein, R4 is -CH2-, -CH2CH2-, -CH2CH2CH2-; And / or, R5 is -H or -CH3.

11. The modified polyurethane of any of claims 1-3, wherein, The polyurethane segment comprises a structure unit G from a polyisocyanate and a structure unit H from an oligomeric polyol.

12. The modified polyurethane of claim 11, wherein, The polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

13. The modified polyurethane of claim 11, wherein, The oligomeric polyol is a polyether polyol.

14. The modified polyurethane of claim 13, wherein, The oligomeric polyol is selected from at least one of polypropylene glycol-2000, polypropylene glycol-3000 and polypropylene glycol-4000.

15. The modified polyurethane of any of claims 1-3, wherein, The viscosity of the modified polyurethane at 25℃ is 200-400 mPa / s.

16. The modified polyurethane of any of claims 1-3, wherein, Two adjacent polyurethane segments are connected by the functional structure unit; and the end of the macromolecular chain of the modified polyurethane is the acrylate end-capping group.

17. The modified polyurethane of any of claims 1-3, wherein, The macromolecular chain of the modified polyurethane further comprises a linking group shown in general formula -NHCO between the polyurethane segment and the functional structure unit.

18. A process for the preparation of the modified polyurethane according to any one of claims 1 to 17, characterized in that, The method comprises: (1) under the presence of a catalyst, polycondensation reaction of a polyisocyanate and an oligomeric polyol to generate a solution A containing a polyurethane; (2) copolymerizing solution A, the interpolymer and the disulfide chain extender to obtain a polymer precursor; wherein the interpolymer contains structural unit C shown in formula (2), structural unit K shown in formula (6), structural unit E shown in formula (4) and structural unit F from a mono-olefin, Formula (2), Formula (6), Formula (4); (3) end-capping the polymer precursor with an end-capping agent to obtain the modified polyurethane; wherein the weight average molecular weight of the oligomeric polyol is 2000-4000 g / mol; the weight average molecular weight of the interpolymer is 5000-8300 g / mol.

19. The preparation method according to claim 18, wherein, the molar ratio of the polyisocyanate to the oligomeric polyol is (2-2.5):1; and / or the amount of the catalyst is 0.05-0.1 wt% relative to the total amount of the feed; and / or the amount of the disulfide chain extender is 1.5-2.5 wt%; and / or the amount of the interpolymer is 15-22 wt%; and / or the molar ratio of the end-capping agent to the polyisocyanate is 1:(2-2.5), wherein the total amount of the feed is the sum of the amounts of the polyisocyanate, the oligomeric polyol, the interpolymer, the catalyst, the disulfide chain extender and the end-capping agent.

20. The method of making according to claim 18, wherein, The disulfide chain extender is selected from the group consisting of compounds having the general formula or wherein Z3, Z4, Z5, Z6are each independently phenylene or a C1-C6straight chain or branched alkylene group; Alternatively, the end-capping agent has a structure shown in formula (A5), Formula (A5), wherein R4 is selected from C1-C5 straight or branched chain alkylene; R5 is selected from -H or C1-C3 straight or branched chain alkyl; Alternatively, the catalyst is an organotin catalyst.

21. The method of making according to claim 20, wherein, Z3, Z4 are each independently -CH2CH2- or -C6H4-, Alternatively, R4 is selected from -CH2-, -CH2CH2-, -CH2CH2CH2-; and R5 is -H or -CH3.

22. The method of making according to claim 18, wherein, the end-capping agent is selected from at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; Alternatively, the catalyst is dibutyltin dilaurate and / or stannous octoate; Alternatively, the disulfide chain extender is selected from at least one of bis(2-hydroxyethyl) disulfide, 4,4'-dithiodianiline and 2,2-dithiodianiline.

23. The method of making according to claim 18, wherein, The mass fraction of the structural unit E is 15-45% based on the total weight of the interpolymer.

24. The method of making according to any one of claims 18-23, wherein, The mono-olefin is isobutylene.

25. The preparation method according to any one of claims 18-23, wherein, the conditions of the polycondensation reaction include: reaction time: 1-2 h, reaction temperature: 60-70℃; Alternatively, the conditions of the copolymerization reaction include: reaction time: 2-4 h, reaction temperature: 70-80℃; Alternatively, the conditions of the end-capping reaction include: reaction time: 1-2 h, reaction temperature: 80-85℃.

26. A self-repairing antibacterial photocured coating film composition, which contains the modified polyurethane according to any one of claims 1-17.

27. The self-repairing antibacterial photocured coating film composition according to claim 26, wherein, The composition further contains an active diluent and a photoinitiator.

28. The self-repairing antibacterial photocured coating composition according to claim 27, wherein, The modified polyurethane is 35-45 parts, the active diluent is 52-60 parts and the photoinitiator is 3-5 parts based on the total amount of the composition.

29. Use of the modified polyurethane according to any one of claims 1-17 in a self-repairing antibacterial photocured coating film.

30. A method for preparing a self-repairing antibacterial photocured coating film, characterized by, The preparation method comprises the following steps: (1) mixing the modified polyurethane, the active diluent and the photoinitiator to obtain a mixture A; (2) curing the mixture A to obtain the self-repairing antibacterial photocured coating film; The modified polyurethane is the modified polyurethane according to any one of claims 1-17.

31. The preparation method according to claim 30, wherein, The active diluent is at least one selected from the group consisting of tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate and isobornyl acrylate.

32. The method of manufacturing according to claim 31, wherein, The active diluent is tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate and isobornyl acrylate.

33. The method of manufacturing according to claim 32, wherein, The mass ratio of tripropyleneglycol diacrylate: 1,6-hexanediol diacrylate: isobornyl acrylate is (15-17):(10-15):(25-30).

34. The method of manufacturing according to claim 30, wherein, The photoinitiator is at least one selected from the group consisting of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone and (2,4,6-trimethylbenzoyl) diphenyl phosphine oxide.

35. The method of manufacturing according to claim 34, wherein, The photoinitiator is 2-hydroxy-2-methyl-1-phenylpropanone.

36. The preparation method according to any one of claims 30-35, wherein, The mixing condition comprises a temperature of 30-60℃ and a time of 2-5h; and / or The curing condition comprises a temperature of 20-30℃ and a time of 1min-10min.

37. The method of making according to any one of claims 30-35, wherein, The modified polyurethane is 35-45 parts, the active diluent is 52-60 parts and the photoinitiator is 3-5 parts by weight.

38. A self-repairing antibacterial photocured coating film prepared by the preparation method according to any one of claims 30-37.

39. Use of the self-repairing antibacterial photocured coating film according to claim 38 for surface decoration of public articles.

40. An article having a surface with the self-repairing antibacterial photocured coating film according to claim 39.

Images