Modified polyurethane as well as preparation method and application thereof, self-repairing antibacterial photocuring coating composition as well as preparation method and application thereof and product of self-repairing antibacterial photocuring coating composition

Abstract

The invention relates to the technical field of organic photocuring, in particular to modified polyurethane, a preparation method and application of the modified polyurethane, a self-repairing antibacterial photocuring coating composition, a preparation method and application of the self-repairing antibacterial photocuring coating composition, and a product of the self-repairing antibacterial photocuring coating composition. A macromolecular chain of the modified polyurethane provided by the invention comprises a polyurethane chain segment, a functional structure unit and an acrylate end-capping group. The modified polyurethane provided by the invention contains the quaternary ammonium salt and has relatively good bactericidal performance, the quaternary ammonium salt is high in stability, the antibacterial ability of a coating film is improved to a certain extent under the synergistic effect of an imidazole ring and the quaternary ammonium salt, and the hardness of the coating film prepared from the modified polyurethane is remarkably improved due to the existence of the imidazole ring; the disulfide bond can partially or completely recover the mechanical property and integrity of the modified polyurethane under the stimulation of external conditions such as light, heat or acid-base, so that the modified polyurethane has good self-repairing property, and the fracture self-repairing rate can reach 90% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of organic photocuring, and in particular to a modified polyurethane and a preparation method and application thereof, a self-repairing antibacterial photocuring coating composition and a preparation method and application thereof and a product thereof. Background Art

[0002] UV-curable coatings are widely used in the coating field due to their advantages of environmental protection, energy saving, high efficiency, and fast film formation rate. However, UV-curable coatings themselves do not have the ability to resist microbial or bacterial erosion. On the other hand, during actual use, coatings usually have microcracks, scratches, or even damage due to friction, collision, etc. This weakens the dimensional stability and mechanical strength of the coating to varying degrees, and even causes bacteria to adhere and multiply at the damaged site.

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

[0004] Therefore, in order to extend the service life of the coating, the development of long-lasting, low-toxic and self-repairing antibacterial coatings is of great significance to production and life. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of environmental pollution, slow film forming speed, short service life and poor antibacterial effect in the prior art photocuring coating preparation process, and to provide a modified polyurethane and its preparation method and application, a self-repairing antibacterial photocuring coating composition and preparation method and application and product. The self-repairing antibacterial photocuring coating prepared by the method has the advantages of environmentally friendly preparation process, fast film forming speed, long service life, good antibacterial effect and self-repairing.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a modified polyurethane, wherein the macromolecular chain of the modified polyurethane comprises a polyurethane segment, a functional structural unit and an acrylate end-capping group; the functional structural unit comprises a structural unit A having a -SS- group and a 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 a structure represented by the general formula -O-Z1* or -NH-Z2*, and Z1 and Z2 are each independently a C1-C6 straight chain or branched alkylene group,

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

[0009]

[0010] R 1 , R 3 Each is independently selected from a C1-C6 straight or branched alkylene group, R 2 is selected from a straight chain or branched alkenyl group, R 4 A straight or branched chain alkyl group selected from -H or C1-C6; * is the position 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 a 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) copolymerizing solution A, an embedded copolymer and a disulfide bond extender to obtain a polymer precursor; the embedded copolymer contains a structural unit C represented by formula (2), a structural unit K represented by formula (6), a structural unit E represented by formula (4) and a structural unit F derived from a monoolefin,

[0014]

[0015] (3) subjecting the polymer precursor and the end-capping agent to an end-capping reaction to obtain a modified polyurethane;

[0016] R1, R2, R3, R 1 , R 2 , R 3 , R 4 The definition of is the same as that of the modified polyurethane described in the present invention.

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

[0018] A fourth aspect of the present invention provides a self-repairing antibacterial photocurable coating composition, which contains the modified polyurethane described in the present invention.

[0019] The fifth aspect of the present invention provides an application of the modified polyurethane described in the present invention in a self-repairing antibacterial cured coating.

[0020] A sixth aspect of the present invention provides a method for preparing a self-repairing antibacterial photocurable coating film, the preparation method comprising the following steps:

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

[0022] (2) curing the mixture A to obtain a self-repairing antibacterial light-cured coating;

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

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

[0025] An eighth aspect of the present invention provides an application of the self-repairing antibacterial photocuring coating film described in the present invention in surface finishing of public goods.

[0026] A ninth aspect of the present invention provides a product having the self-repairing antibacterial photocured coating film of the present invention on its surface.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The modified polyurethane provided by the present invention contains a quaternary ammonium salt, has good bactericidal performance and high stability, and the synergistic effect of the imidazole ring and the quaternary ammonium salt improves the antibacterial ability of the coating to a certain extent. The presence of the imidazole ring, on the one hand, enhances the wear resistance of the coating, and on the other hand, reduces the amount of the polymer containing the antibacterial component under the premise of achieving an ideal antibacterial effect, reduces the influence of the quaternary ammonium salt antibacterial unit on the water absorption of the coating, and increases the hydrolysis stability of the material; the disulfide bond can partially or completely restore the mechanical properties and integrity of the modified polyurethane itself under the stimulation of external conditions such as light, heat or acid and alkali, so that the modified polyurethane of the present invention has good self-repairing property, and the fracture self-repair rate can reach more than 90%.

[0029] Furthermore, the photocuring technology provided by the present invention has outstanding advantages in the preparation of antibacterial polymer thin film coatings. This method has mild reaction conditions, fast reaction speed, and high efficiency, which is beneficial to maintaining the activity of antibacterial groups and avoiding the disadvantages of loss of antibacterial activity due to traditional thermal polymerization and its processing process. It is green, environmentally friendly, and highly practical. DETAILED DESCRIPTION

[0030] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0031] The first aspect of the present invention provides a modified polyurethane, wherein the macromolecular chain of the modified polyurethane comprises a polyurethane segment, a functional structural unit and an acrylate end-capping group; the functional structural unit comprises a structural unit A having a -SS- group and a 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 a structure represented by the general formula -O-Z1* or -NH-Z2*, and Z1 and Z2 are each independently a C1-C6 straight chain or branched alkylene group,

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

[0034]

[0035] R 1 , R 3 Each is independently selected from a C1-C6 straight or branched alkylene group, R 2 is selected from C2-C6 straight or branched alkenyl, R 4 A straight or branched chain alkyl group selected from -H or C1-C6; * is the position 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 the present invention contains a quaternary ammonium salt, has good bactericidal performance and high stability, the synergistic effect of the imidazole ring and the quaternary ammonium salt improves the antibacterial ability of the coating to a certain extent, and the presence of the imidazole ring significantly improves the hardness of the coating prepared from the modified polyurethane; the disulfide bond can partially or completely restore the mechanical properties and integrity of the modified polyurethane itself under the stimulation of external conditions such as light, heat or acid and alkali, so that the modified polyurethane of the present invention has good self-repairing performance, and the fracture self-repairing rate can reach more than 90%.

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

[0038] In the present invention, the copolymer chain represented by R can be connected through the N element in the structural unit B shown in formula (1), thereby bringing good antibacterial properties to the macromolecular chain structure of the modified polyurethane and preventing the high molecular antibacterial unit from migrating and losing easily.

[0039] In the present invention, both ends of the structural unit B can be respectively bonded to different polyurethane 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 are each independently a structure represented by 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 R b -HC=CH-R a -Structure shown, R a is 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 4Selected 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 one of isobutylene, isopentene, isohexene, isoheptene and isooctene.

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

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

[0052] According to a particularly preferred embodiment of the present invention, in R of the structural unit B, the molar ratio of structural unit E: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 the general formula In the structure shown in FIG. 1 , Z3, Z4, Z5, and Z6 are each independently a phenylene group or a C1-C6 straight-chain or branched alkylene group. In the structure shown, 1 is connected to SS, and 2 is connected to NH. The two ends of the above general formula of the structural unit A can be respectively connected to different polyurethane segments in 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-position or meta-position 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 the structural unit A to the structural unit B is (3-10):1.

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

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

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

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

[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 polyisocyanate 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 adopting the above preferred embodiment, the versatility and excellent performance 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 at least one selected from polypropylene glycol-2000, polypropylene glycol-3000 and polypropylene glycol-4000. By adopting the above-mentioned preferred embodiment, the versatility and excellent performance 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 segment 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, the functional structural units and the acrylate end-capping groups is 1:(1-1.2):(0.8-1).

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

[0069] According to a particularly preferred embodiment of the present invention, two adjacent polyurethane segments are connected via the functional structural unit, and the end of the macromolecular chain of the modified polyurethane is the acrylate end-capping group.

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

[0071] In the present invention, the connecting group may be generated by the reaction of the -NCO group originally present at the end of the polyurethane segment with the -OH or -NH group present at the end of the functional structural unit.

[0072] A second aspect of the present invention provides a method for preparing a 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) copolymerizing solution A, an embedded copolymer and a disulfide bond extender to obtain a polymer precursor; the embedded copolymer contains a structural unit C represented by formula (2), a structural unit K represented by formula (6), a structural unit E represented by formula (4) and a structural unit F derived from a monoolefin,

[0075]

[0076] (3) subjecting the polymer precursor and the end-capping agent to an end-capping reaction to obtain a modified polyurethane;

[0077] Among them, R1, R2, R3, R 1 , R 2 , R 3 , R 4 The definition of is the same as that described in the modified polyurethane of the present invention.

[0078] In the present invention, the disulfide bond extender and the hydroxyl group embedded in the copolymer react with the -NCO bond in the polyurethane precursor to achieve linkage with the polyurethane, and the formed polymer precursor is then capped at the end of the polyurethane chain segment by a capping agent, and the group of the capping agent is introduced to obtain the modified polyurethane.

[0079] The modified polyurethane prepared by the method of the present invention contains a quaternary ammonium salt and an imidazole salt copolymer as an antibacterial component, which is connected to the polyurethane main chain in a polymerization manner via terminal hydroxyl groups, thereby overcoming the problem of seepage or dissolution that is prone to occur when adding a blended antibacterial agent; in addition, the polymer antibacterial unit is not easy to migrate and lose, and is safer and less toxic than small molecule organic antibacterial agents, so the prepared modified polyurethane has low toxicity and good antibacterial properties.

[0080] According to a particularly preferred embodiment of the present invention, the isocyanate needs to be pretreated and tested for isocyanate group content, and both the pretreatment and the test are carried out 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 end point 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 modified polyurethane obtained needs to be cooled to room temperature before discharging.

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

[0084] According to a particularly preferred embodiment of the present invention, the amount of the catalyst 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 blocking 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 respective feed amounts of the polyisocyanate, the oligomeric polyol, the embedded copolymer, the catalyst, the disulfide bond chain extender and the end-capping agent.

[0089] In the present invention, the optional range of types of the polyisocyanate is relatively wide, and commonly used polyisocyanates can be used in the present invention. 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.

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

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

[0092] According to a particularly preferred embodiment of the present invention, the disulfide bond chain extender is selected from at least one of bis(2-hydroxyethyl) disulfide, 4,4′-disulfodiphenylamine, and 2,2-disulfodiphenylamine. By adopting the above-mentioned preferred embodiment, the disulfide bond chain extender contains a reversible covalent disulfide bond, which can partially or completely restore the mechanical properties and integrity of the polymer itself under the stimulation of external conditions such as light, heat or pH, and theoretically can achieve unlimited repairs.

[0093] In the present invention, the type of the capping agent can be selected from a wide range, and commonly used capping agents can be used in the present invention, such as hydroxyl functional acrylate capping agents. According to a preferred embodiment of the present invention, the capping agent has a structure shown in formula (A5),

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

[0095] According to a particularly preferred embodiment of the present invention, the end-capping agent is selected from at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate. The above-mentioned preferred embodiment overcomes the problem of seepage or dissolution that is prone to occur when adding a blended antibacterial agent by polymerizing the terminal hydroxyl group to the end of the polyurethane macromolecular main chain.

[0096] In the present invention, the catalyst has a wide range of optional types, and commonly used catalysts can be used in the present invention. According to a particularly preferred embodiment of the present invention, the catalyst is an organic tin catalyst, preferably dibutyltin dilaurate and / or stannous octoate.

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

[0098] (i) subjecting a monoolefin and a monomer e providing a structural unit E to a cationic polymerization reaction in the presence of an initiator system and a solvent to obtain a binary copolymer solution containing structural units E and structural units F;

[0099] (ii) washing the binary copolymer solution with water and then subjecting it to a halogenation reaction to obtain a halogenated polymer;

[0100] (iii) subjecting the halogenated polymer to a salification reaction with an imidazole compound and a polyol amine to obtain the embedded copolymer.

[0101] Among them, in (iii), the imidazole compound and the polyol amine can be bonded to part of the halogenated groups in the halogenated polymer through the N element contained in each of them through the salification reaction, thereby forming the structural unit C and the structural unit K respectively.

[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 the present invention, the type of the monoolefin can be selected from a wide range, and commonly used monoolefins can be used in the present invention. According to a particularly preferred embodiment of the present invention, the monoolefin is selected from one of isobutylene, isopentene, 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 present invention, the amount of monomer e added is based on the total weight of the embedded copolymer, wherein the mass fraction of the structural unit E is 15-45%.

[0106] According to a particularly preferred embodiment of the present invention, the added amounts of the imidazole compound and the monomer e satisfy that in the embedded copolymer, the molar ratio of the structural unit C: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 in the range consisting of any two of the above values.

[0107] According to a particularly preferred embodiment of the present invention, the added amounts of polyol amine and monomer e satisfy that in the embedded copolymer, the molar ratio of the structural unit K:structural unit E is 1:(0.3-0.5), for example, 1:0.3, 1:0.4, 1:0.5, or any value in the range consisting 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 that in the embedded copolymer, the molar ratio of the structural unit F:structural unit E is 1:(2-5), for example, 1:2, 1:3, 1:4, 1:5, or any value in the range consisting of any two of the above values.

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

[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 the monomer e. For example, the initiator system contains a compound that can provide protons (such as HCl), at least one Lewis acid (ethylaluminum dichloride, diethylaluminum chloride) and at least one activator (such as tetrahydrobenzoquinone, tetrachlorobenzoquinone, tetracyanobenzoquinone and dichlorodicyanobenzoquinone). In the present invention, hydrogen chloride / ethylaluminum dichloride / tetrachlorobenzoquinone is used as the initiator system (the molar concentration ratio is 1:10:1) to illustrate the advantages of the present invention, but the present invention is not limited to this. ; The solvent can be an alkane or a halogenated alkane. In the present invention, hexane / dichloromethane (60 / 40, V / V) is used as a solvent to exemplify the advantages of the present invention, but the present invention is not limited thereto; There is no special restriction on the amount of the solvent and the initiator in the initiator system, and those skilled in the art can select them according to their needs, and no further details are given here; Wherein, the conditions for the cationic polymerization reaction include: the temperature is -60°C to -20°C, and a medium-low molecular weight fully saturated binary copolymer containing structural unit D and structural unit E is prepared, and the monomer e and the olefin carbon-carbon double bond in the monoolefin are subjected to the polymerization reaction. Wherein, the monomer e provides the structural unit E.

[0114] (ii) The binary copolymer undergoes the halogenation reaction with halogen, and the conditions of the halogenation reaction include: washing the binary copolymer solution with water, and then performing a pulse (10s) photobromination reaction at room temperature by slowly dropping liquid bromine with a 595nm light source, the bromination reaction time is 60-150min, and then washing the brominated gel solution with water and centrifuging to obtain a halogenated polymer. 4The halogen is substituted to form a halogenated side group in the macromolecular chain of the binary copolymer.

[0115] The conditions of the salification reaction in (iii) include: a reaction temperature of 50-80°C, specifically, firstly adding a polyol amine compound dropwise, reacting for 10-24 hours, and then adding an imidazole compound to the reaction system to continue reacting for 10-24 hours; after the salification reaction is completed, adding a certain amount of anhydrous ether to the system, a large amount of solid precipitates, and filtering, washing, and drying to obtain the embedded copolymer. The imidazole compound and the polyol amine react with the halogenated side group through the N element contained in each of them, and the structural unit C and structural unit K in the embedded copolymer are formed accordingly.

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

[0117] In the present invention, the disulfide bond extender reacts with the isocyanate group contained in the polyurethane contained in the solution A to form a connection shown as -NHCO- through the hydroxyl group or amino group contained in the disulfide bond extender during the copolymerization reaction of step (2).

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

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

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

[0121] According to a particularly preferred embodiment of the present invention, the conditions of the end-capping reaction include: reaction time: 1-2h, reaction temperature: 80-85° C. The terminal hydroxyl group contained in the end-capping agent reacts with the isocyanate terminal group in the polymer precursor, and the isocyanate terminal group is converted into the terminal group provided by the end-capping agent by forming an -NHCO- group, thereby overcoming the problem of exudation or dissolution that is prone to occur when adding a blended antibacterial agent.

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

[0123] The modified polyurethane prepared by the invention uses quaternary ammonium salt and imidazole salt copolymer as antibacterial components, and the high-molecular antibacterial unit is not easy to migrate and lose. Compared with small-molecule 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-repairing antibacterial photocurable coating composition, which contains the modified polyurethane described in the present invention.

[0125] The present invention provides a self-repairing antibacterial cured coating film containing the polymer of the present invention, which can improve the antibacterial property, mechanical property and self-repairing property of the self-repairing antibacterial cured coating film.

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

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

[0128] A fifth aspect of the present invention provides an application of the modified polyurethane described in the present invention in a self-repairing antibacterial cured coating.

[0129] By applying the modified polyurethane prepared by the present invention to a self-repairing antibacterial cured coating, the antibacterial property, mechanical properties and self-repairing property of the coating can be improved.

[0130] A sixth aspect of the present invention provides a method for preparing a self-repairing antibacterial photocurable coating film, the preparation method comprising the following steps:

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

[0132] (2) curing the mixture A to obtain a self-repairing antibacterial light-cured coating;

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

[0134] In the present invention, the types of the reactive diluent can be selected from a wide range, and all commonly used types can be used in the present invention. According to a particularly preferred embodiment of the present 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 above-mentioned preferred embodiment, multiple active functional groups of the reactive diluent can participate in the reaction, which can not only improve the curing rate of the photocurable coating, but also enhance the comprehensive 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 above-mentioned preferred embodiment, since multiple active functional groups of the active diluent can participate in the reaction, the curing rate of the photocurable coating is further improved, and the comprehensive 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-hydroxycyclohexyl benzophenone, 2-hydroxy-2-methyl-1-phenylacetone, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide. By adopting the above-mentioned preferred embodiment, the absorption spectrum of the photoinitiator matches the emission spectrum of the radiation light source, which can efficiently induce the chemical reaction between the 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: temperature of 30-60° C. and time of 2-5 h.

[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 min-10 min.

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

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

[0143] According to a particularly preferred embodiment of the present invention, the mixture A is allowed to stand for degassing, and then evenly coated on a tin-plated tinplate sheet with a wire rod coater, the cured layer thickness is controlled to be 0.2-0.5 mm, and placed in a UV curing machine for photocuring to obtain a self-repairing antibacterial photocured coating.

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

[0145] The photocuring technology provided by the present 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 is conducive to maintaining the activity of antibacterial groups and avoids the disadvantages of loss of antibacterial activity caused by traditional thermal polymerization and its processing process. It is green, environmentally friendly, and highly practical.

[0146] An eighth aspect of the present invention provides an application of the self-repairing antibacterial photocuring coating film described in the present invention in surface finishing of public goods.

[0147] A ninth aspect of the present invention provides a product having the self-repairing antibacterial photocured coating film of the present invention on its surface.

[0148] Self-repair efficiency: The sample is divided into two parts, one part is cut from the middle with scissors, the two parts are tightly fitted and placed in a 50℃ oven for 2 hours, and the other part is the original sample without any treatment. The tensile strength of the repaired sample and the original sample after 2 hours is tested respectively and their self-repair efficiency is calculated. Among them, the self-repair 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 object was Gram-negative bacteria Escherichia coli. The plate count method was used to test the antibacterial rate of the coating against Escherichia coli at different times. The whole process was carried out under sterile operation.

[0150] Water absorption rate: Cut the membrane into 25mm×25mm slices, dry them in an oven at 60℃ for 24h, weigh them as W1, and then place the dried slices in 50mL deionized water for 24h, absorb the unabsorbed water on the surface, weigh them as W2, then the water absorption rate = (W2-W1 / W1)×100%.

[0151] The molecular weight of the polymer was determined by 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, a flow rate of 1.0 mL / min, and a calibration curve determined using PS as the standard.

[0152] Viscosity test method: Use a digital rotational viscometer and select a suitable rotor to measure the viscosity of the sample at various temperatures. The resin must flow over the rotor.

[0153] Pencil hardness test: According to the national standard GB / T6739-2006, the pencil hardness grades used are 2B, B, HB, H, 2H to 6H. The test first uses a 6H pencil, and each pencil is tested 5 times on the coating, rotating pencils of different hardness until only one of the five traces tested is a scratch on the coating, leaving a mark on the substrate, that is, the hardness of the cured film is represented by the pencil hardness of the next level of this pencil.

[0154] In order to make the present invention easier to understand, the present invention will be described in detail below in conjunction with examples. These examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The raw materials involved in the examples are all commercially available unless otherwise specified. The composition structure of the obtained polymer is determined by feeding.

[0155] Preparation Example

[0156] For illustration of the preparation of embedded copolymers:

[0157] Using hydrogen chloride / ethylaluminum dichloride / tetrachlorobenzoquinone (the molar concentration ratio is 1:1:1) as the initiation system and hexane / dichloromethane (60 / 40, V / V) as the solvent, isobutylene and p-methylstyrene are subjected to cationic polymerization reaction in the range of -60°C to -20°C 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 is subjected to a photobromination reaction by slowly dropping liquid bromine at room temperature and under the condition of 595 nm light source pulse (10 s) irradiation. The bromination reaction time is 60-150 min. The obtained product is washed with water and centrifuged for dehydration to obtain a brominated polymer.

[0159] N-methyldiethanolamine and the brominated polymer are subjected to a salification reaction at a reaction temperature of 50-80°C for 10-24 hours, and then allyl imidazole is added to the reaction system to continue the reaction for 10-24 hours. After the reaction is completed, a certain amount of anhydrous ether is added to the system, and a large amount of solid is precipitated. After filtering, washing, and drying, the embedded copolymer is obtained, and its schematic structure is shown below:

[0160]

[0161] Adjust the conditions and the amount of raw materials added to obtain:

[0162] Embedded copolymer I: weight average molecular weight of 8000 g / mol, no 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 embedded 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%, molar ratio of structural unit C shown in formula (2) to structural unit E shown in formula (4) is 1:0.2, molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.4, 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%, molar ratio of structural unit C shown in formula (2) to structural unit E shown in formula (4) is 1:0.1, molar ratio of structural unit K shown in formula (6) to structural unit E shown in formula (4) is 1:0.4, molar ratio of structural unit F to structural unit E shown in formula (4) is 1:2;

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

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

[0167] Example 1

[0168] A thermometer and a constant pressure dropping funnel were placed in a three-necked flask and 4.44 g of pretreated isophorone diisocyanate was added, followed by 0.03 g of dibutyltin dilaurate (catalyst) and stirred evenly. 30.06 g of oligopropylene glycol PPG3000 was slowly added dropwise, and after the addition was completed, the temperature was raised to 60 ° C and reacted for 1 hour to generate a polyurethane solution A with a weight average molecular weight of 4000 g / mol. Samples were continuously taken during the reaction process and the isocyanate group content in the system was measured.

[0169] When the isocyanate group content was reduced to half of the original, 6.96 g of embedded copolymer II and 0.69 g of bis(2-hydroxyethyl) disulfide (disulfide bond extender) were added to the polyurethane solution A, the temperature was raised to 85°C and the reaction was continued for 1 hour, and 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 process, samples were continuously taken and the isocyanate group content in the system was measured. When the content was less than 0.3%, the reaction was terminated, and 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 placed in a three-necked flask and 4.44 g of pretreated isophorone diisocyanate was added, followed by 0.03 g of dibutyltin dilaurate (catalyst) and stirred evenly. 30.06 g of oligopropylene glycol PPG3000 was slowly added dropwise, and after the addition was complete, the temperature was raised to 60 °C and reacted for 1 h to generate a polyurethane solution A with a weight average molecular weight of 4000 g / mol. Samples were continuously taken during the reaction process and the isocyanate group content in the system was measured.

[0172] When the isocyanate group content was reduced to half of the original, 6.96 g of embedded copolymer III and 0.69 g of bis(2-hydroxyethyl) disulfide were added to the polyurethane solution A, the temperature was raised to 85°C and the reaction was continued for 1 hour, and finally 1.04 g of hydroxyethyl methacrylate 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. When the content was less than 0.3%, the reaction was terminated, the solution was cooled to room temperature, and the material was discharged. The obtained viscous liquid was the 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 placed in a three-necked flask and 4.01 g of pretreated toluene diisocyanate was added, followed by 0.02 g of dibutyltin dilaurate (catalyst) and stirred evenly. 20.01 g of oligopropylene glycol PPG2000 was slowly added dropwise, and after the addition was complete, the temperature was raised to 60°C and reacted for 1 h to generate a polyurethane solution A with a weight average molecular weight of 3600 g / mol. Samples were continuously taken during the reaction process and the isocyanate group content in the system was measured.

[0175] When the isocyanate group content was reduced to half of the original, 5.18 g of embedded copolymer IV and 0.77 g of bis(2-hydroxyethyl) disulfide were added to the polyurethane solution A, the temperature was raised to 80°C and the reaction was continued for 1 hour, and 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. When the content was less than 0.3%, the reaction was terminated, the solution was cooled to room temperature, and the material was discharged. The obtained viscous liquid was the 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 placed in a three-necked flask and 4.01 g of pretreated toluene diisocyanate was added, followed by 0.02 g of dibutyltin dilaurate (catalyst) and stirred evenly. 20.01 g of oligopropylene glycol PPG2000 was slowly added dropwise, and after the addition was complete, the temperature was raised to 60°C and reacted for 1 h to generate a polyurethane solution A with a weight average molecular weight of 3600 g / mol. Samples were continuously taken during the reaction process and the isocyanate group content in the system was measured.

[0178] When the isocyanate group content was reduced to half of the original, 5.18 g of embedded copolymer V and 0.77 g of bis(2-hydroxyethyl) disulfide were added to the polyurethane solution A, the temperature was raised to 80°C and the reaction was continued for 1 hour, and 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 process, samples were continuously taken and the isocyanate group content in the system was measured. When the content was less than 0.3%, the reaction was terminated, the solution was cooled to room temperature, and the material was discharged. The obtained viscous liquid was the 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] The same as Example 1, except that no embedded copolymer II was added and other conditions remained unchanged, and the viscous liquid obtained was 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] The same as Example 1, except that bis(2-hydroxyethyl) disulfide was not added and other conditions remained unchanged, and the viscous liquid obtained was 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] The same as Example 3, except that the embedded copolymer I was added to replace the embedded copolymer IV. The viscous liquid obtained was 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 Example 1-11

[0186] All raw materials were weighed in parts by weight according to the ratio in Table 1, and the synthesized modified polyurethane, active diluent, and photoinitiator were added to the container respectively, and magnetic stirring was performed under light-proof conditions until the mixture was uniform, the mixing temperature was 50°C, and the time was 3 hours to obtain a mixture A; then, the mixture was evenly coated on the tin-plated tinplate sheet with a wire rod coater, and the thickness of the cured layer was controlled to be 0.3 mm, and the mixture was placed in an ultraviolet light curing machine (the power of the light curing machine was 1200 W, the main emission wavelength was 365 nm and 385 nm, the irradiation distance was 22 cm, the temperature was 25°C, and the time was 4 minutes.) for light curing to obtain a light-cured coating film. The light-cured coating film was prepared according to the formula shown in Table 1 below.

[0187] Table 1

[0188]

[0189] Test Case

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

[0191] Table 2

[0192]

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

[0194] In addition, imidazole / quaternized isobutylene / p-methylstyrene copolymer is used as the antibacterial component, and the terminal hydroxyl group is polymerized into the main chain of the polyurethane resin to overcome the problem of exudation or dissolution that is easy to occur when adding a blended antibacterial agent, and the bactericidal unit can be well protected, and has good bactericidal performance. For example: the anti-Escherichia coli rate of the coating prepared by Preparation Examples 1-6, Preparation Example 8, Preparation Example 10, and Preparation Example 11 is greater than 92% when in contact for 3 hours. When the embedded copolymer (Preparation Example 7) is not added, the anti-Escherichia coli rate of the prepared coating is only 16.5% and 13.1% when in contact for 1 hour and 3 hours, and it does not have antibacterial properties. It can be seen from Preparation Examples 4 and Preparation Examples 11 that when the mass fraction of p-methylstyrene in the antibacterial copolymer and the molar ratio of the antibacterial components derived from the p-methylstyrene structural unit in the copolymer are the same, the coating containing imidazole units has a slightly stronger antibacterial property. Because quaternary ammonium salt is a broad-spectrum antibacterial agent, and the imidazole ring is a structural unit with antibacterial properties, they can play a synergistic role in antibacterial properties and improve the antibacterial properties of the coating.

[0195] By comparison of Preparation Example 2, Preparation Example 3 and Preparation Example 5 and Preparation Example 6, it can be seen that within the preferred range of raw material ratio, the more the content of antibacterial component, the stronger the antibacterial effect. However, as the antibacterial component continues to increase (Preparation Example 5 and Preparation Example 10), the antibacterial property does not change much, so from the perspective of saving raw materials, the addition of antibacterial agent can be controlled within a certain range. At the same time, the presence of imidazole rings significantly improves the hardness of the coating. For example: the hardness of the coating containing imidazole units (Preparation Example 3) is 2H, while the hardness of the coating in Preparation Example 11 is only HB, with poor hardness. By Preparation Example 1, Preparation Example 2 and Preparation Example 4 and Preparation Example 5, it can be seen that, under the same conditions, as the content of imidazole ring units increases, the pencil hardness of the coating gradually increases, which is conducive to increasing the wear resistance of the coating.

[0196] The film water absorption is measured to determine its water absorption and hydrolytic stability. Within the preferred range of raw material ratio, the film that does not contain the quaternary ammonium salt antibacterial unit possesses certain hydrophobicity and is difficult for water absorption and dissolution. Usually, as the quaternary ammonium salt component increases gradually, the water absorption increases accordingly, and this is the result that the quaternary ammonium salt cation is easy to combine with water. But because the antibacterial unit contains hydrophobic benzene ring structure and hydrophobic alkyl chain, the overall influence on the water absorption of the film is little, and the water absorption is all less than 2.3. If the antibacterial polyurethane component content is too high (preparation example 10), the water absorption rises to 3.5, affecting the hydrolytic stability of the film material.

[0197] It can be seen from the results of the embodiments and comparative examples that the presence of the imidazole-containing structural unit C in the modified polyurethane of the present invention, on the one hand, enhances the wear resistance of the coating film, and on the other hand, while achieving an ideal antibacterial effect, reduces the amount of polymer containing antibacterial components, reduces the influence of the quaternary ammonium salt antibacterial unit on the water absorption of the coating film, and increases the hydrolysis stability of the material.

[0198] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A modified polyurethane, characterized in that: The modified polyurethane has a macromolecular chain comprising a polyurethane segment, a functional structural unit and an acrylate end-capping group; wherein the functional structural unit comprises a structural unit A having a -SS- group and a structural unit B represented by formula (1); wherein R1 is a C1-C6 straight chain or branched alkyl group, R2 and R3 are each independently a structure represented by the general formula -O-Z1* or -NH-Z2*, wherein Z1 and Z2 are each independently a C1-C6 straight chain or branched alkylene group, and R is a copolymer chain comprising a structural unit C represented by formula (2), a structural unit D represented by formula (3), a structural unit E represented by formula (4), and a structural unit F derived from a monoolefin, Among them, R 1 , R 3 Each is independently selected from a C1-C6 straight or branched alkylene group, R 2 is selected from C2-C6 straight or branched alkenyl, R 4 -H or a C1-C6 straight or branched alkyl group, * is the position connected to the N element in formula (1); X and Y are each independently selected from F, Cl, Br or I.

2. The modified polyurethane according to claim 1, wherein R1 is -CH3 or -CH2CH3; and / or, Z1 and Z2 are each independently -CH2CH2- or -CH2CH2CH2-, preferably R2 and R3 are each independently a structure represented by the general formula -O-Z1*, more preferably R2 and R3 are both -O-CH2CH2*; and / or, R 1 , R 3 Each is independently selected from -CH2- or -CH2CH2-; and / or, R 2 R b -HC=CH-R a -The structure shown, where R a is blank or selected from -CH2- or -CH2CH2-, R b Selected from -H, -CH3 or -C2H5, preferably R b Selected from -H; and / or, R 4 Selected from -CH3 or -C2H5; and / or, X and Y are each independently Cl or Br; And / or, the monoolefin is selected from one of isobutylene, isopentene, isohexene, isoheptene and isooctene.

3. The modified polyurethane according to claim 1 or 2, wherein In the R of the structural unit B, The molar ratio of structural unit C: structural unit E is 1:(0.2-0.5); The molar ratio of structural unit D: structural unit E is 1:(0.3-0.5); The molar ratio of structural unit E: structural unit F is 1:(2-10); Preferably, the weight average molecular weight of the copolymer chain is 9000-15000 g / mol.

4. The modified polyurethane according to any one of claims 1 to 3, wherein The structural unit A has the general formula The structure shown, wherein Z3, Z4, Z5, and Z6 are each independently phenylene or a C1-C6 straight-chain or branched alkylene; Preferably, Z3 and Z4 are each independently -CH2CH2- or -C6H4-; Preferably, the structural unit A has The structure shown.

5. The modified polyurethane according to any one of claims 1 to 4, wherein In the functional structural unit, the molar ratio of the structural unit A to the structural unit B is (3-10):

1.

6. The modified polyurethane according to any one of claims 1 to 5, wherein The acrylate end-capping group has a structure shown in formula (5), Wherein, R4 is selected from a C1-C5 straight or branched alkylene group, preferably -CH2-, -CH2CH2-, -CH2CH2CH2-; And / or, R5 is selected from -H or C1-C3 straight chain or branched alkyl, preferably -H or -CH3.

7. The modified polyurethane according to any one of claims 1 to 6, wherein The polyurethane segment contains a structural unit G derived from a polyisocyanate and a structural unit H derived from an oligomeric polyol; Preferably, the polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate; Preferably, the oligomeric polyol is a polyether polyol, preferably at least one selected from polypropylene glycol-2000, polypropylene glycol-3000 and polypropylene glycol-4000; Preferably, the weight average molecular weight of the polyurethane segment is 3000-5000 g / mol.

8. The modified polyurethane according to any one of claims 1 to 7, wherein Based on the total amount of the modified polyurethane, the molar ratio of the polyurethane segment, the functional structural unit and the acrylate end-capping group is 1:(1-1.2):(0.8-1); Preferably, the weight average molecular weight of the modified polyurethane is 9000-15000 g / mol, and the viscosity at 25° C. is 200-400 mPa / s.

9. The modified polyurethane according to any one of claims 1 to 8, wherein Two adjacent polyurethane chain segments are connected via the functional structural unit; the end of the macromolecular chain of the modified polyurethane is the acrylate end-capping group.

10. The modified polyurethane according to any one of claims 1 to 9, wherein The macromolecular chain of the modified polyurethane further comprises a connecting group represented by the general formula -NHCO located between the polyurethane segment and the functional structural unit.

11. A method for preparing a modified polyurethane, characterized in that: The method includes: (1) in the presence of a catalyst, polyisocyanate and oligomeric polyol are subjected to polycondensation reaction to generate a solution A containing polyurethane; (2) copolymerizing solution A, an embedded copolymer and a disulfide bond extender to obtain a polymer precursor; wherein the embedded copolymer contains a structural unit C represented by formula (2), a structural unit K represented by formula (6), a structural unit E represented by formula (4) and a structural unit F derived from a monoolefin, (3) subjecting the polymer precursor and the end-capping agent to an end-capping reaction to obtain a modified polyurethane; Among them, R1, R2, R3, R 1 , R 2 , R 3 , R 4 The definition is the same as that in any one of claims 1 to 10.

12. The preparation method according to claim 11, wherein The molar ratio of the polyisocyanate to the oligomeric polyol is (2-2.5):1; and / or The amount of the catalyst used is 0.05-0.1 wt% relative to the total amount of feed; and / or The disulfide bond extender is used in an amount of 1.5-2.5 wt %; and / or The embedded copolymer is used in an amount of 15-22 wt%; and / or The molar ratio of the blocking agent to the polyisocyanate is 1:(2-2.5), The total amount of the feed is the sum of the respective feed amounts of the polyisocyanate, the oligomeric polyol, the embedded copolymer, the catalyst, the disulfide bond extender and the end-capping agent.

13. The preparation method according to claim 11 or 12, wherein: The polyisocyanate is selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate; Preferably, the oligomer polyol is a polyether polyol, preferably at least one selected from polypropylene glycol-2000, polypropylene glycol-3000 and polypropylene glycol-4000, and has a weight average molecular weight of 2000-4000 g / mol; Preferably, the disulfide bond 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 a C1-C6 straight chain or branched alkylene, preferably Z3 and Z4 are each independently -CH2CH2- or -C6H4-, and more preferably, the disulfide bond extender is selected from at least one of bis(2-hydroxyethyl) disulfide, 4,4'-dithiodiphenylamine, and 2,2-dithiodiphenylamine; Preferably, the capping agent has a structure shown in formula (A5), Wherein, R4 is selected from C1-C5 straight chain or branched alkylene, preferably -CH2-, -CH2CH2-, -CH2CH2CH2-; R5 is selected from -H or, C1-C3 straight chain or branched alkyl, preferably -H or -CH3, and it is further preferred that the end-capping agent is selected from at least one of hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate; Preferably, the catalyst is an organic tin catalyst, preferably dibutyltin dilaurate and / or stannous octoate.

14. The preparation method according to any one of claims 11 to 13, wherein: The weight average molecular weight of the embedded copolymer is 5000-8300 g / mol; Preferably, the monoolefin is selected from one of isobutylene, isopentene, isohexene, isoheptene and isooctene, preferably isobutylene; Preferably, based on the total weight of the embedded copolymer, the mass fraction of the structural unit E is 15-45%; Preferably, the molar ratio of the structural unit C: structural unit E is 1:(0.1-0.5); Preferably, the molar ratio of the structural unit K: structural unit E is 1:(0.3-0.5); Preferably, the molar ratio of the structural unit F:structural unit E is 1:(2-5).

15. The preparation method according to any one of claims 11 to 14, wherein: The conditions of the polycondensation reaction include: reaction time: 1-2h, reaction temperature: 60-70°C; Preferably, the copolymerization reaction conditions include: reaction time: 2-4h, reaction temperature: 70-80°C; Preferably, the conditions for the end-capping reaction include: reaction time: 1-2h, reaction temperature: 80-85°C.

16. A modified polyurethane obtained by the preparation method according to any one of claims 11 to 15.

17. A self-repairing antibacterial photocurable coating composition, comprising the modified polyurethane according to any one of claims 1 to 10 and 16; Preferably, the composition further contains a reactive diluent and a photoinitiator; Preferably, based on the total amount of the composition, the modified polyurethane is 35-45 parts, the reactive diluent is 52-60 parts, and the photoinitiator is 3-5 parts.

18. Use of the modified polyurethane according to any one of claims 1 to 10 and 16 in a self-repairing antibacterial curing coating.

19. A method for preparing a self-repairing antibacterial light-cured coating, characterized in that: The preparation method comprises the following steps: (1) mixing modified polyurethane, reactive diluent and photoinitiator to obtain mixture A; (2) curing the mixture A to obtain a self-repairing antibacterial light-cured coating; Wherein, the modified polyurethane is the modified polyurethane described in any one of claims 1-10 and 16.

20. The preparation method according to claim 19, wherein: The reactive diluent is selected from at least one of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate and isobornyl acrylate, preferably tripropylene glycol diacrylate, 1,6-hexanediol diacrylate and isobornyl acrylate; Preferably, the mass ratio of tripropylene glycol diacrylate:1,6-hexanediol diacrylate:isobornyl acrylate is (15-17):(10-15):(25-30); Preferably, the photoinitiator is selected from at least one of 1-hydroxycyclohexyl benzophenone, 2-hydroxy-2-methyl-1-phenylpropanone and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, preferably 2-hydroxy-2-methyl-1-phenylpropanone.

21. The preparation method according to claim 19 or 20, wherein: The mixing conditions include: temperature of 30-60°C and time of 2-5h; and / or The curing conditions include: temperature of 20-30° C. and time of 1 min-10 min.

22. The preparation method according to any one of claims 19 to 21, wherein: In parts by weight, the modified polyurethane is 35-45 parts, the active diluent is 52-60 parts, and the photoinitiator is 3-5 parts.

23. A self-repairing antibacterial photocured coating film obtained by the preparation method according to any one of claims 19 to 22.

24. Use of the self-repairing antibacterial photocuring coating according to claim 23 in surface finishing of public goods.

25. A product having the self-repairing antibacterial photocured coating according to claim 23 on its surface.

Images