Bio-based chain extender and application thereof

Abstract

The invention provides a bio-based chain extender and application thereof, the bio-based chain extender comprises a bio-based compound 2, 5-bark dimethyl casein and / or 5-shin methyl-2-bark methyl casein, and the bio-based compound 2, 5-bark dimethyl casein and / or 5-shin methyl-2-bark methyl casein is used as the bio-based chain extender to synthesize modified polyurethane with antibacterial and mildew-proof performance. The polyurethane glycoside material can be endowed with lasting, stable and broad-spectrum antibacterial performance and mildew-proof performance, an antibacterial agent does not need to be additionally added, and the problems of environmental pollution, short antibacterial time, unstable antibacterial performance and the like caused by migrating of the antibacterial agent in the use process of the polyurethane glycoside material are solved; particularly, the bio-based chain extender is a bio-based source, is safe and environment-friendly, has a remarkable antibacterial and anti-withering modification effect on a polyurethane material, and has a wide application prospect in the fields of medical materials, public facilities, health protection and the like.

Description

Technical Field

[0001] The present application belongs to the field of polymer materials and relates to a bio-based chain extender and its application, specifically, to the application of the bio-based chain extender in the synthesis of modified polyurethane with antibacterial and mildew-proof properties. Background Art

[0002] Polyurethane (PU) is the abbreviation of polyurethane, which is a polymer containing many repeated carbamate groups (-NHCOO-) on the main chain of the polymer, usually obtained by stepwise polymerization of polyisocyanate or polyisocyanate and polyol. Polyurethane has excellent comprehensive properties, such as excellent wear resistance, oil resistance, water resistance, good radiation resistance and air permeability resistance, excellent mechanical properties, and easy molding and processing, so it has good applications in many fields. In particular, it contains amide groups and ester groups similar to human proteins, has good biocompatibility and is widely used in medical materials such as medical catheters, adhesives, cardiovascular stents, etc. However, ordinary polyurethane products do not have antibacterial function, so the development of polyurethane materials with excellent antibacterial properties will help its application in the fields of medical materials, personal protective products, sterile packaging, etc.

[0003] At present, the commonly used antibacterial modification methods include adding antibacterial agents, such as mixing small molecule antibacterial agents into PU substrates by physical blending or surface coating, and then achieving antibacterial function by releasing bactericides or directly contacting bacteria. This type of antibacterial PU is easy to prepare, but the antibacterial agents added therein may migrate or lose their antibacterial properties due to physical wear, so the antibacterial properties will decrease over time, and the antibacterial agents that migrate to the environment may also pollute the environment. For example, Hong Fenghong (Preparation and Structure and Properties of Polyurethane / Nanosilver Composite Films, 2007, Beijing University of Chemical Technology, Master's Thesis) dissolved polyurethane monomer particles in DMAC, added silver nitrate or silver acetate solution, and then synthesized PU with antibacterial properties by heat treatment. Its main antibacterial mechanism is to kill bacteria by using the released silver particles.

[0004] Alternatively, a chemical modification method is used to obtain PU with relatively stable antibacterial properties by grafting or block copolymerizing antibacterial groups with antibacterial properties. The antibacterial groups are mainly quaternary ammonium salts, guanidine salts, imidazole heterocyclic quaternary ammonium salts, etc., and the mildew-proof agents include 8-hydroxyquinolinone, tetrachloro-4-(methylsulfonyl)pyridine, salicylanilide or bis(tri-n-butyltin) oxide, etc., which can achieve antibacterial and mildew-proof modification of polyurethane. Among them, quaternary ammonium salt antibacterial agents are the most studied and applied antibacterial agents at present, with fast bactericidal action and good bactericidal effect. However, traditional quaternary ammonium salt small molecule antibacterial agents also have disadvantages such as high toxicity, short effectiveness, volatility, and poor chemical stability. Although the method of connecting organic molecules containing quaternary ammonium salts to the main chain of polyurethane can prolong its antibacterial effectiveness, the introduction of ionic organic molecules will also change the hydrophilicity and other properties of polyurethane, and there is still a risk of environmental harm. Even if the group modification is carried out, the preparation procedure is complicated. Therefore, it is necessary to seek healthier and greener methods to modify polyurethane for antibacterial properties. In particular, there are few reports on polyurethanes that have both antibacterial and mildew-proof effects and modification methods, and there is a large market demand.

[0005] Based on this, the present application adopts the bio-based compounds 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime as chain extenders, which have the dual functions of chain extension and antibacterial and mildew resistance, and have the characteristics of small introduced molecules, no many branches, and little effect on the mechanical properties of polyurethane. The modified polyurethane formed contains furan oxime amino ester bonds and has a stable structure; the furan oxime-based chain extender itself is a bio-based compound, which is safe and environmentally friendly and is an ideal polyurethane modified chain extender. Summary of the invention

[0006] The purpose of the present invention is to provide a bio-based chain extender and an application thereof, and to use the bio-based chain extender to synthesize modified polyurethane to solve the problem of poor antibacterial and mildew-proof effects of polyurethane materials in the prior art. In particular, the present invention avoids the problems of unstable antibacterial effects, short antibacterial time, environmental pollution caused by migration of antibacterial agents, etc., which are caused by improving the antibacterial properties of polyurethane by adding external antibacterial agents in the prior art, and the problems of high toxicity, short effectiveness, high volatility, poor chemical stability, etc. of traditional quaternary ammonium salt small molecule antibacterial agents.

[0007] To achieve the above purpose, this application adopts the following technical solutions:

[0008] A bio-based chain extender, comprising 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime, having a structure shown in formula (I) and / or formula (II):

[0009]

[0010] -C=NOH in formula (I) and formula (II) is an oxime group.

[0011] The above-mentioned bio-based chain extender can be used to synthesize modified polyurethane with antibacterial and antifungal properties. Diisocyanate and polyol are used as reaction raw materials. The isocyanate group and the oxime group are reacted by adding a chain extender to generate a polyoxime urethane bond (-NH-COO-N=C-), so that the prepolymer molecular chain formed by the diisocyanate and the polyol is connected to form a macromolecular polyoxime urethane, which is the modified polyurethane.

[0012] Preferably, the chain extender comprises a bio-based chain extender E.

[0013] More preferably, the biological chain extender E is 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime.

[0014] Specifically, the preparation method of the modified polyurethane comprises:

[0015] The modified polyurethane is synthesized from diisocyanate A, polyol B and the chain extender; the modified polyurethane is polyoxime urethane containing furan oxime urethane bonds.

[0016] Preferably, the preparation of the modified polyurethane includes two steps of prepolymerization and polymerization;

[0017] The prepolymerization comprises firstly performing a prepolymerization reaction on diisocyanate A and polyol B to obtain prepolymer C;

[0018] The polymerization includes adding a chain extender to the prepolymer C and then performing a polymerization reaction to prepare a modified polyurethane with antibacterial and antifungal properties.

[0019] The prepolymer C has one or both end groups of -N=C=O and contains a structural unit of formula (III):

[0020]

[0021] Wherein, R1 and two adjacent amide bonds are derived from dicyanate A, R2 and two adjacent -O- bonds are derived from polyol B, n is a positive integer depending on the average molecular weight of the polyol, and x is a positive integer of 1 to 20.

[0022] Optionally, x in the prepolymer C is a positive integer of 1 to 20; preferably, x in the prepolymer C is a positive integer of 1 to 16; more preferably, the lower limit of x in the prepolymer C is 1, 2, 3, 4, 5, 6 or 7; the upper limit of x in the prepolymer C is 14, 15, 16, 17, 18, 19 or 20.

[0023] After the bio-based chain extender E participates in the formation of modified polyurethane, a furanoxime aminoester bond is formed on the main chain of the molecule. The furanoxime amino ester bond has antibacterial and anti-mildew effects, and the chain extender E forms a stable covalent bond with the polyurethane main chain, with a stable structure. Its antibacterial effect is durable and there is no problem of antibacterial agent migration. It is essentially different from the method of physically adding antibacterial agents such as nanosilver to polyurethane.

[0024] As one of the preferred embodiments of the present invention, when the bio-based chain extender E is 2,5-furandicarboxaldehyde dioxime, the modified polyurethane contains a structural unit represented by formula (IV):

[0025]

[0026] As one of the preferred embodiments of the present invention, when the bio-based chain extender E is 5-hydroxymethyl-2-furancarbaldehyde oxime, the modified polyurethane, i.e., polyoxime urethane, contains a structural unit represented by formula (V):

[0027]

[0028] Among them, R1 and two adjacent amide bonds are derived from diisocyanate A, R2 and two adjacent -O- bonds are derived from polyol B, n is a positive integer depending on the average molecular weight of the polyol, x is a positive integer of 1 to 20, and m is a positive integer of 3 to 10.

[0029] Preferably, wherein x is a positive integer of 1 to 16, the lower limit of x in the modified polyurethane is 1, 2, 3, 4, 5, 6 or 7, and the upper limit of x in the modified polyurethane is 14, 15, 16, 17, 18, 19 or 20.

[0030] Optionally, m is a positive integer of 3 to 10, preferably, m in the modified polyurethane is a positive integer of 5 to 8; the lower limit of m in the modified polyurethane is 3, 4, 5 or 6, and the upper limit of m in the modified polyurethane is 7, 8, 9 or 10.

[0031] As one of the preferred embodiments of the present invention, the chain extender further includes a chain extender D.

[0032] The added chain extender D not only plays a chain extension role, but also can better control the amount of the bio-based chain extender E under the premise of ensuring the molecular weight of the modified polyurethane, leaving more room for regulation in terms of antibacterial properties, mechanical properties, permeability, color, etc.

[0033] Preferably, the chain extender D is C2 to C 12 of saturated polyols.

[0034] More preferably, the chain extender is ethylene glycol, butanediol, pentanediol, hexanediol, octanediol, decanediol, dodecanediol or a combination of several thereof.

[0035] Preferably, when the chain extender D is present, the synthetic modified polyurethane contains structural units represented by formula (VI) and / or formula (VII):

[0036]

[0037] Among them, R1 and two adjacent amide bonds are derived from diisocyanate A, R2 and two adjacent -O- bonds are derived from polyol B, R3 and adjacent -O- bonds are derived from the chain extender D, n is a positive integer depending on the average molecular weight of the polyol, x is a positive integer of 1 to 20, y is a positive integer of 1 to 20; m is a positive integer of 3 to 10; z is a positive integer of 0 to 10.

[0038] Preferably, wherein x is a positive integer of 1 to 16, the lower limit of x in the modified polyurethane is 1, 2, 3, 4, 5, 6 or 7, and the upper limit of x in the modified polyurethane is 14, 15, 16, 17, 18, 19 or 20.

[0039] Preferably, y is a positive integer of 1 to 16, the lower limit of y in the modified polyurethane is 1, 2, 3, 4, 5, 6 or 7, and the upper limit of x in the modified polyurethane is 14, 15, 16, 17, 18, 19 or 20.

[0040] Preferably, m is a positive integer of 3 to 10, preferably, m in the modified polyurethane is a positive integer of 5 to 8; the lower limit of m in the modified polyurethane is 3, 4, 5 or 6, and the upper limit of m in the modified polyurethane is 7, 8, 9 or 10.

[0041] Preferably, z is a positive integer of 0 to 10, preferably, z in the modified polyurethane is a positive integer of 0 to 8; the lower limit of z in the modified polyurethane is 0, 1, 2, 3, 4, 5 or 6, and the upper limit of z in the modified polyurethane is 7, 8, 9 or 10.

[0042] Furthermore, the diisocyanate A is selected from one or a combination of hexamethylene diisocyanate, L-lysine diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate (IPDI), trans-1,4-cyclohexane diisocyanate, and dicyclohexylmethane 4,4′-diisocyanate (HMDI).

[0043] Preferably, the structures of the above diisocyanates do not contain a benzene ring.

[0044] Optionally, the diisocyanate is any one or a combination of the following structures:

[0045]

[0046] The polyol B is selected from one or a combination of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone glycol, and polybutadiene glycol. The molecular weight range of the polyol is 400 to 10000 g / mol. Optionally, the lower limit of the molecular weight of the polyol is 400 g / mol, 500 g / mol, 600 g / mol, 700 g / mol, and 800 g / mol. The upper limit of the molecular weight of the polyol is 4000 g / mol, 5000 g / mol, 6000 g / mol, 7000 g / mol, 8000 g / mol, 9000 g / mol, and 10000 g / mol.

[0047] When diisocyanate A and polyol B are prepolymerized, the molar ratio is 1-3:1, the amount of the catalyst is 0.005-0.3% of the total mass of diisocyanate A and polyol B, the reaction temperature is 50-80°C, the reaction time is 1-8 hours, preferably 2-5 hours, and the reaction gas atmosphere is an inert gas, such as nitrogen or argon.

[0048] Optionally, when the molar ratio of the diisocyanate A and the polyol B is 1:1 during prepolymerization, it is easy to form a prepolymer with terminal groups of -OH and -C=N=O respectively; when the molar ratio of the diisocyanate A and the polyol B is 2:1 during prepolymerization, it is easy to form a prepolymer with most of the molecular chains having terminal groups of -C=N=O; when the molar ratio of the diisocyanate A and the polyol B is greater than 2:1 during prepolymerization, it is easy to form a prepolymer molecular chain with terminal groups of -C=N=O.

[0049] Preferably, when the diisocyanate A and the polyol B are prepolymerized, the molar ratio is 1.025-2.5:1. Optionally, when the diisocyanate A and the polyol B are prepolymerized, the molar ratio is 1-1.025:1, 1.025-1.5:1, 1.5-2:1, 2-2.5:1 or 2.5-3:1.

[0050] Preferably, the amount of the catalyst is 0.01-0.1% of the total mass of AB. Optionally, the amount of the catalyst is 0.005-0.01%, 0.01-0.02%, 0.02-0.05%, 0.05-0.1%, 0.1-0.2% or 0.2%-0.3% of the total mass of AB.

[0051] As a preferred embodiment, the catalyst in the prepolymerization step is a tin-containing catalyst, including stannous octoate, octyltin maleate, dibutyltin diacetate, and monobutyltin triisooctoate.

[0052] As a preferred embodiment, the catalyst in the prepolymerization step includes a titanic acid catalyst, including tetrabutyl titanate.

[0053] As a preferred embodiment, the catalyst in the prepolymerization step includes an antimony-containing catalyst, including antimony glycol and antimony acetate.

[0054] Furthermore, the molar ratio of the bio-based chain extender E to the diisocyanate is 0.1 to 3:1, and the chain extender D is C2 to C 12 Saturated polyols such as ethylene glycol, butanediol, pentanediol, hexanediol, octanediol, decanediol, dodecanediol or a combination of the latter.

[0055] The molar ratio of the chain extender D to the diisocyanate A is 0-2:1. Preferably, the molar ratio of the chain extender D to the diisocyanate A is 0-1.5:1. Optionally, the molar ratio of the chain extender D to the diisocyanate A is 0-0.01:1, 0.01-0.03:1, 0.03-0.05:1, 0.05-0.07:1, 0.07-0.4:1, 0.4-0.5:1, 0.5-1:1, 1-1.5:1 or 1.5-2:1.

[0056] After adding the chain extender D and the bio-based chain extender E, the reaction temperature is 50-100° C., the reaction time is 2-10 hours, the reaction gas atmosphere is an inert gas, and after the reaction is completed, a polyamino oxime ester solution is obtained.

[0057] Optionally, the reaction temperature after adding the chain extender D and the bio-based chain extender E is 50-100°C, preferably, the reaction temperature after adding the chain extender D and the bio-based chain extender E is 70-95°C, the lower limit of the reaction temperature after adding the chain extender D and the bio-based chain extender E is 50°C, 55°C, 60°C, 65°C or 70°C, and the upper limit of the reaction temperature after adding the chain extender D and the bio-based chain extender E is 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C.

[0058] Optionally, the reaction time after adding the chain extender D and the bio-based chain extender E is 2 to 10 hours. Preferably, the reaction time after adding the chain extender D and the bio-based chain extender E is 2 to 3 hours, 3 to 4 hours, 4 to 5 hours, 5 to 6 hours, 7 to 8 hours, or 9 to 10 hours.

[0059] As a preferred embodiment, a dispersant F may be added during the polymerization process; the dispersant F includes any one of methanol, ethanol, toluene, tetrahydrofuran, dichloromethane, chloroform, etc., or a combination of several thereof.

[0060] Preferably, the amount of the dispersant used is 5-50% of the total mass of the reaction materials in the polymerization reaction system.

[0061] More preferably, the amount of the dispersant F is 5-10%, 10-20%, 20-30%, 30-40% or 40-50% of the total mass of the reaction material.

[0062] After the modified polyurethane solution is desolvated, the modified polyurethane of one of the invention purposes of the present application is obtained. The obtained modified polyurethane contains furanoxime urethane bonds, that is, it is a polyoxime urethane.

[0063] Preferably, the desolvation method comprises any one of rotary evaporation, vacuum drying, plate heating, water bath or oil bath nitrogen blowing, and the temperature is 60-120°C.

[0064] More preferably, the desolvation temperature is 70-100°C; the lower limit of the desolvation temperature is 60°C, 65°C, 70°C, 75°C or 80°C, and the upper limit of the desolvation temperature is 85°C, 90°C, 95°C, 100°C, 110°C or 120°C.

[0065] The modified polyurethane prepared based on the above technical solution has an inhibitory and / or bactericidal effect on bacteria and fungi.

[0066] Specifically, the bacteria include Escherichia coli and Staphylococcus aureus; and / or the fungi include Aspergillus niger, Chaetomium globosum, Penicillium funiculum, Paecilomyces variotii, and Trichoderma longibrachiatum.

[0067] The modified polyurethane prepared by the technical solution of the present invention and having an inhibitory and / or bactericidal effect on bacteria and fungi can be used in the fields of medical materials, personal protective equipment, and aseptic packaging.

[0068] The beneficial effects of this application include:

[0069] 1) The bio-based chain extender provided in the present application is used to synthesize polyurethane materials, which has a good chain extension effect and a significant effect of increasing the molecular weight.

[0070] 2) The present application uses bio-based compounds 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime as chain extenders, and the synthesized modified polyurethane has dual antibacterial and mildew-proof effects. The formed modified polyurethane contains furanoxime amino ester bonds, has a stable structure, low mobility, and has the characteristics of small introduced molecules, no large number of branches, and little effect on the mechanical properties of the polyurethane.

[0071] 3) The polyurethane connected by the furanoxime group chain extender synthesized by the technical solution of the present application can significantly improve the antibacterial and antifungal effects of the polyurethane, and achieve the technical effect of intrinsic antibacterial without the need to add additional antibacterial agents, thereby avoiding the problems of environmental pollution, short antibacterial time, unstable antibacterial performance, etc. caused by the migration of antibacterial agents during the use of the polyurethane material; in particular, there is no need to add additional small molecule antibacterial agents such as quaternary ammonium salts, which may cause the polyurethane material to have high toxicity, short antibacterial time, high volatility, poor chemical stability, and other problems.

[0072] 4) The bio-based chain extender provided in this application is a bio-based chemical with a wide range of raw material sources, low eco-toxicity, and safety and environmental protection.

[0073] 5) The polyurethane (polyoxime urethane) based on furan oxime urethane bond synthesized by using the chain extender provided by the technical solution of the present application not only has an amide bond similar to human protein, but also has antibacterial and antifungal functions, and has great application prospects in the fields of medical care and health.

[0074] 6) In the technical solution provided in the present application, two chain extenders are selected for coordinated use in synthesizing modified polyurethane. The dosage of the bio-based chain extender can be designed and effectively adjusted as needed to improve the antibacterial and anti-mildew properties of polyurethane in a more economical and efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 This is a Fourier infrared spectrum of the modified polyurethane obtained after polymerization in Example 1 of the present application. DETAILED DESCRIPTION

[0076] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0077] The endpoints and any values ​​of the range disclosed in this application are not limited to the precise range or value, and these ranges or values ​​should be understood to include close to these ranges or values. For numerical ranges, the endpoint values ​​and individual point values ​​of each range can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0078] Unless otherwise specified, the reaction reagents or raw materials of the present application are purchased through commercial channels, and the reagent grade is AR or >98%.

[0079] Among them, in the bio-based chain extender E, 5-hydroxymethyl-2-furancarbaldehyde oxime is a commercially available product (purchased from Jinjinle Chemical in the following examples).

[0080] The preparation method of 2,5-furandicarboxaldehyde dioxime in the bio-based chain extender E includes using 2,5-furandicarboxaldehyde from biomass as a raw material, using a hydroxylamine aqueous solution as an oximating agent, adding an acid to adjust the pH value of the reaction system, and the generated 2,5-furandicarboxaldehyde dioxime as a catalyst to self-catalyze and complete the reaction process. In this application, it is used as a chain extender, which is a bio-based chain extender E. Specifically, the preparation method of 2,5-furandicarboxaldehyde dioxime (DFFD) refers to CN112830911B.

[0081] In this application, the hydrochloric acid-di-n-butylamine titration method is used to determine the concentration of isocyanate, with specific reference to "GB / T12009.4-2016 Aromatic isocyanates for the production of plastic polyurethanes Part 4: Determination of isocyanate content" to judge the reaction progress.

[0082] The molecular weight of prepolymer and polymer was measured by Ubbelohde viscometer.

[0083] The technical solution of the present application is described in detail below through specific embodiments.

[0084] Example 1

[0085] This embodiment provides a modified polyurethane based on furan ring and oxime group, that is, a preparation method of the modified polyurethane, and the specific steps include:

[0086] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polytetrahydrofuran diol (PTMG, average molecular weight of 1000 g / mol) was charged into a flask, 2 times the chemical equivalent of PTMG (30 mmol) of isophorone diisocyanate (IPDI) was added into the flask, 0.02% of the total mass of PTMG and IPDI was added with stannous isooctanoate, the mixture was stirred and reacted at 65° C. for 3.5 hours, and nitrogen was continuously introduced to obtain a prepolymer, the average molecular weight of the prepolymer was about 2300 g / mol, and x was about 2.

[0087] 2. Polymerization: Add 15 mmol of 2,5-furandicarboxaldehyde dioxime (DFFD) and 20% of the total mass of the polymerization system, anhydrous tetrahydrofuran, into a flask, heat to 75°C and stir for 5 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0088] 3. Desolventization: The modified polyurethane solution obtained by the polymerization reaction in step 2 was placed on a heating table at 80° C. and heated for 48 hours for desolventization reaction to obtain a modified polyurethane with an average molecular weight of 22,000 g / mol and m of about 9.

[0089] See also Figure 1 The infrared spectrum of the modified polyurethane obtained after polymerization is shown in Figure 3324 cm -1It is the characteristic peak of NH on the amide bond, combined with 1708cm -1 C=O and 1101cm -1 The CO at 2850-2940 cm -1 Represents -CH2 on polyol, 770~960cm -1 and 1536cm -1 Represents the bending vibration on the furan ring and the C=O stretching vibration on the furan ring, indicating that the furan ring extender is connected to the polyurethane. 3170cm -1 is the OH group on DFFD oxime, Figure 1 The absence of this characteristic peak indicates that there is no free oxime group, 1435~1465cm -1 It is NO, indicating that the oxime group on the chain extender E is connected to the isocyanate group.

[0090] Example 2

[0091] This example adopts the method of Example 1 to prepare a modified polyurethane, except that the amount of 2,5-furandicarboxaldehyde dioxime (DFFD) is changed to 13.5 mmol, and 1.5 mmol of butanediol is added to obtain a prepolymer with an average molecular weight of about 2200 g / mol, x of about 2, and a modified polyurethane with an average molecular weight of 23000 g / mol and m of about 10.

[0092] Example 3

[0093] This example adopts the method of Example 2 to prepare modified polyurethane, except that the average molecular weight of polytetrahydrofuran diol is changed to 400 g / mol, the molar amounts of DFFD and butanediol are changed to 3 mmol and 12 mmol, the prepolymerization temperature is changed to 80° C., the prepolymerization time is changed to 2 hours, the polymerization temperature is changed to 75° C., and the polymerization time is changed to 5 hours. The average molecular weight of the prepolymer is about 3300 g / mol, x is about 5, and the modified polyurethane is obtained, with an average molecular weight of 24000 g / mol and m of about 7.

[0094] Example 4

[0095] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polycaprolactone diol (average molecular weight of 1000 g / mol) was charged into a flask, and hexamethylene diisocyanate (30 mmol) twice the chemical equivalent of polycaprolactone diol was added into the flask, and the above two reagents and 0.02% of octyltin maleate were added, and the mixture was stirred and reacted at 70° C. for 3.5 hours, and nitrogen was continuously introduced to obtain a prepolymer, the average molecular weight of the prepolymer was about 3600 g / mol, and x was about 3.

[0096] 2. Polymerization: 18 mmol of DFFD and 20% of the total mass of anhydrous tetrahydrofuran were added into a flask, heated to 75°C and stirred for 5 hours in a nitrogen atmosphere. The polymerization reaction was completed to obtain a modified polyurethane solution, which was a homogeneous viscous solution.

[0097] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 50°C for desolventization reaction until it was completely dry to obtain a modified polyurethane with an average molecular weight of about 29000 g / mol and m of about 8.

[0098] Example 5

[0099] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polypropylene glycol (average molecular weight of 2000 g / mol) was charged into a flask, 1.5 times the chemical equivalent of polypropylene glycol (22.5 mmol) of L-lysine diisocyanate was added into the flask, the above two reagents and 0.005% of octyltin maleate were added, the mixture was stirred and reacted at 70° C. for 5 hours, and nitrogen was continuously introduced to obtain a prepolymer, the average molecular weight of the prepolymer was about 9000 g / mol, and x was about 4.

[0100] 2. Polymerization: Add 9 mmol of DFFD, 1.5 mmol of ethylene glycol, and 5% of the total mass of anhydrous tetrahydrofuran into a flask, heat to 75°C and stir continuously for 4 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0101] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 50° C. to remove the reaction solvent until it was completely dry, thereby obtaining a modified polyurethane having an average molecular weight of about 27,000 g / mol and m of about 3.

[0102] Example 6

[0103] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polyethylene glycol (average molecular weight of 10000 g / mol) was charged into a flask, 1.5 times the chemical equivalent of polyethylene glycol (15.375 mmol) of trimethyl hexamethylene diisocyanate was added into the flask, the above two reagents and 0.005% of octyltin maleate were added, the mixture was stirred and reacted at 80° C. for 1 hour, and nitrogen was continuously introduced to obtain a prepolymer.

[0104] 2. Polymerization: Add 46.125 mmol of DFFD and 30.75 mmol of ethylene glycol and 5% of the total mass of anhydrous tetrahydrofuran into a flask, heat to 50°C and stir for 10 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0105] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 80° C. to remove the reaction solvent until it was completely dry, thereby obtaining a modified polyurethane having an average molecular weight of about 31200 g / mol and m of about 3.

[0106] Example 7

[0107] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polytetrahydrofuran diol (mean molecular weight is 1000 g / mol) is loaded into a flask, 2 times of polytetrahydrofuran diol chemical equivalent (30 mmol) of trans-1,4-cyclohexane diisocyanate is added into the flask, the above two reagent masses and 0.3% of tetrabutyl titanate are added, the mixture is stirred and reacted at 70 ℃ for 1 hour, and nitrogen is continuously introduced to obtain a prepolymer.

[0108] 2. Polymerization: Add 7.5 mmol of DFFD and 7.5 mmol of pentanediol and 50% of the total mass of anhydrous toluene into a flask, heat to 100°C and stir for 2 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0109] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 90° C. to remove the reaction solvent until it was completely dry, thereby obtaining a modified polyurethane having an average molecular weight of about 11000 g / mol and m of about 7.

[0110] Example 8

[0111] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polybutadiene glycol (average molecular weight of 5000 g / mol) was charged into a flask, 3 times the chemical equivalent of polybutadiene glycol (45 mmol) of dicyclohexyl methane 4,4′-diisocyanate was added into the flask, the above two reagents and 0.1% antimony acetate were added, the mixture was stirred and reacted at 50° C. for 8 hours, and nitrogen was continuously introduced to obtain a prepolymer, the average molecular weight of the prepolymer was 10700 g / mol, and x was about 2.

[0112] 2. Polymerization: Add 30 mmol of DFFD and 3 mmol of dodecanediol and 20% of the total mass of dichloromethane into a flask, heat to 80°C and stir continuously for 6 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0113] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 120° C. to remove the reaction solvent until it was completely dry, thereby obtaining a modified polyurethane having an average molecular weight of about 31600 g / mol and m of about 3.

[0114] Example 9

[0115] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polypropylene glycol (average molecular weight of 400 g / mol) is charged into a flask, 2.2 times the chemical equivalent of polypropylene glycol (33 mmol) of dicyclohexylmethane 4,4′-diisocyanate is added into the flask, the above two reagents and 0.02% of monobutyl tin triisooctanoate are added, the mixture is stirred and reacted at 50° C. for 5 hours, and nitrogen is continuously introduced to obtain a prepolymer, the average molecular weight of the prepolymer is 3800 g / mol, and x is about 6.

[0116] 2. Polymerization: Add 15 mmol of 5-hydroxymethyl-2-furancarbaldehyde oxime (HMFO), 3 mmol of ethylene glycol, and 20% of the total mass of trinitroform into a flask, heat to 75°C and stir continuously for 6 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0117] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed in a vacuum drying oven at 80° C. to remove the reaction solvent until it was completely dry, thereby obtaining a modified polyurethane having an average molecular weight of about 31,000 g / mol and m of about 8.

[0118] Example 10

[0119] In this example, a similar method to that of Example 9 was used to prepare a modified polyurethane, except that the isocyanate was replaced with 1.05 times the chemical equivalent of polypropylene glycol (15.75 mmol) of L-lysine diisocyanate, the chain extender was changed to 47.25 mmol of HMFO and 31.5 mmol of ethylene glycol, the prepolymerization temperature was changed to 60°C, the gas was changed to argon, and the dispersant was changed to tetrahydrofuran to obtain a modified polyurethane with an average molecular weight of about 24,000 g / mol.

[0120] Embodiment 11

[0121] This example adopts a similar method to that of Example 9 to prepare a modified polyurethane, except that the average molecular weight of the polypropylene glycol reagent is increased to 3000 g / mol, the isocyanate is replaced by trimethylhexamethylene diisocyanate with 2 times the chemical equivalent of polypropylene glycol (30 mmol), the chain extender is changed to 13.5 mmol of HMFO and 1.5 mmol of hexamethylene glycol, the dispersant is changed to tetrahydrofuran, the addition amount is 50% of the total mass, the prepolymerization temperature is changed to 70°C, the prepolymerization time is changed to 4 hours, the polymerization temperature is changed to 50°C, and the polymerization time is changed to 10 hours. The average molecular weight of the prepolymer obtained is about 8000 g / mol, x is about 3, and the modified polyurethane obtained has an average molecular weight of about 58000 g / mol and m is about 6.

[0122] Example 12

[0123] This embodiment adopts a similar method to that of embodiment 9 to prepare a modified polyurethane, except that polypropylene glycol is replaced with polytetrahydrofuran diol having an average molecular weight of 1000 g / mol, isocyanate is replaced with isophorone diisocyanate having a chemical equivalent of 1.5 times (22.5 mmol) of polytetrahydrofuran diol, catalyst is replaced with stannous isooctanoate, the addition amount is 0.005% of the total mass of polytetrahydrofuran diol and isophorone diisocyanate, chain extender is replaced with 2.25 mmol of HMFO and 5.25 mmol of decanediol, dispersant is replaced with methanol, prepolymerization temperature is replaced with 60° C., and prepolymerization time is replaced with 4 hours. A modified polyurethane is obtained, and the average molecular weight is about 27000 g / mol.

[0124] Embodiment 13

[0125] In this example, a modified polyurethane is prepared by a method similar to that of Example 12, except that the amount of catalyst added is 0.02% of the total mass of polytetrahydrofuran diol and isophorone diisocyanate, and the chain extender is changed to 3 mmol of HMFO and 4.5 mmol of DFFD to obtain a modified polyurethane with an average molecular weight of about 24,000 g / mol and m of about 5.

[0126] Embodiment 14

[0127] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polyethylene glycol (average molecular weight of 10000 g / mol) was charged into a flask, 3 times the chemical equivalent of polyethylene glycol (45 mmol) of trans-1,4-cyclohexane diisocyanate was added into the flask, the above two reagents and 0.02% of ethylene glycol antimony were added, the mixture was stirred and reacted at 80° C. for 2 hours, and nitrogen was continuously introduced to obtain a prepolymer.

[0128] 2. Polymerization: Add 28.5 mmol of HMFO and 1.5 mmol of octanediol and 5% of the total weight of toluene into a flask, heat to 90°C and continue stirring for 4 hours in a nitrogen atmosphere. The polymerization reaction is completed to obtain a modified polyurethane solution, which is a homogeneous viscous solution.

[0129] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed on a heating plate at 120° C. and heated until dry to obtain a modified polyurethane having an average molecular weight of about 61000 g / mol and m of about 6.

[0130] Embodiment 15

[0131] 1. Prepolymerization: 15 g (15 mmol) of anhydrous polyethylene glycol (average molecular weight of 800 g / mol) was charged into a flask, 12 mmol of hexamethylene diisocyanate and 15 mmol of isophorone diisocyanate were added into the flask, 0.02% of the total mass of the above reagents of dibutyltin diacetate was added, the mixture was stirred and reacted at 80° C. for 2 hours, and nitrogen was continuously introduced to obtain a prepolymer.

[0132] 2. Polymerization: 15 mmol of HMFO and 20% of the total mass of toluene were added into a flask, heated to 100° C. and stirred for 2 hours in a nitrogen atmosphere. The polymerization reaction was completed to obtain a modified polyurethane solution, which was a homogeneous viscous solution.

[0133] 3. Desolventization: The modified polyurethane solution obtained by the reaction was placed on a heating plate at 120° C. and heated until dry to obtain a modified polyurethane having an average molecular weight of about 23,000 g / mol.

[0134] Comparative Example 1

[0135] This comparative example provides a polyurethane, and its preparation method is different from the method for preparing the modified polyurethane in Example 2 in that only the DFFD content is changed to 0, and the addition amount of butanediol is changed to 15 mmol, the average molecular weight of the obtained prepolymer is about 2200 mol / g, x is about 2, the molecular weight of the obtained polyurethane is about 17600 g / mol, m is about 7, and the obtained polyurethane structure does not include furan rings and oxime groups.

[0136] Comparative Example 2

[0137] This comparative example adopts the method of Example 2 to prepare modified polyurethane, except that DFFD is replaced with 2,4-pentanedione dioxime and the dispersant is changed to ethanol. The isocyanate content of the obtained polyoxime urethane is 0 after titration with hydrochloric acid-butanediamine solvent, and the molecular weight of the obtained polyurethane is 18800 g / mol, and m is about 8.

[0138] Antimicrobial testing

[0139] The antibacterial properties of the prepared polyurethane and modified polyurethane were measured with reference to "GB / T 31402-2015 Test method for antibacterial properties of plastic surfaces".

[0140] Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P were used for testing. The number of live bacteria obtained directly after inoculation of the unprocessed Escherichia coli specimen was 2.4×10 4 (cfu / cm 2 ), the number of viable bacteria obtained after the unprocessed specimen was inoculated and placed for 24 hours was 2.1×10 5 (cfu / cm 2), see Table 1 for specific test results.

[0141] Table 1 Antibacterial test results

[0142] Sample source Escherichia coli inhibition rate Staphylococcus aureus inhibition rate Comparative Example 1 3％ 0.05％ Comparative Example 2 2％ 1％ Example 1 100％ 100％ Example 2 99％ 98％ Example 3 96％ 95％ Example 5 99％ 97％ Example 6 100％ 100％ Example 9 100％ 100％ Example 13 99％ 99％ Embodiment 15 100％ 99％

[0143] Anti-mildew performance test:

[0144] The mildew resistance of the prepared polyurethane and modified polyurethane was measured with reference to "GB / T 24128-2018 Evaluation of the mildew resistance effect of plastic mildew inhibitors". The mildew resistance grade description is shown in Table 2. The lower the grade, the better the mildew resistance effect.

[0145] Table 2 Description of mildew resistance level

[0146] Fungal growth Mildew resistance level No obvious bacteria growth at 50 times magnification Level 0 The bacteria are not visible or difficult to see with the naked eye, but can be clearly seen under a magnifying glass Level 1 The bacteria are clearly visible to the naked eye, covering 10-30% of the sample surface. Level 2 The bacteria are clearly visible to the naked eye, covering 30-60% of the sample surface. Level 3 Bacteria are clearly visible to the naked eye, covering more than 60% of the sample surface Level 4

[0147] The fungi used in the mildew resistance test were: Aspergillus niger CGMCC 3.3928, Chaetomium globosum CGMCC 3.3601, Penicillium funiculosum CGMCC 3.3875, Paecilomyces variotii CGMCC 3.4253, and Trichoderma longibrachiatum ATCC 13631. The mildew resistance test results are shown in Table 3.

[0148] Table 3 Anti-mildew test results

[0149] Sample source Mildew resistance level Comparative Example 1 Level 4 Comparative Example 2 Level 4 Example 1 Level 0 Example 2 Level 0 Example 3 Level 0 Example 5 Level 0 Example 6 Level 0 Example 9 Level 0 Example 13 Level 0 Embodiment 15 Level 0

[0150] From the comparison of the antibacterial and mildew-proof test results in Tables 1-3, it can be seen that the modified polyurethane containing furanoxime aminoester bonds prepared by the technical solution of the present invention has a significant antibacterial and mildew-proof effect.

[0151] In particular, DFFD and HMFO as chain extenders can effectively modify the antibacterial and antifungal properties of polyurethane, and have stable structure, simple preparation method, safety and environmental protection, no need for additional antibacterial agents, avoiding the occurrence of polyurethane materials during use, and have broad application prospects.

[0152] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A bio-based chain extender, comprising 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime, having a structure shown in formula (I) and / or formula (II): -C=NOH in formula (I) and formula (II) is an oxime group.

2. Use of the bio-based chain extender as claimed in claim 1 in the synthesis of polyurethane with antibacterial and antifungal properties.

3. A method for preparing a modified polyurethane having antibacterial and anti-mildew properties, characterized in that: Using diisocyanate and polyol as reaction raw materials, adding a chain extender to react isocyanate with oxime to generate polyoxime urethane bonds (-NH-COO-N=C-), so that the prepolymer molecular chains formed by diisocyanate and polyol are connected, and a macromolecular polyoxime urethane containing furan oxime urethane bonds is formed on the main chain of the molecule, which is the modified polyurethane; The chain extender includes a bio-based chain extender E; The biological chain extender E is 2,5-furandicarboxaldehyde dioxime and / or 5-hydroxymethyl-2-furancarboxaldehyde oxime.

4. The preparation method according to claim 3, characterized in that: It includes two steps: prepolymerization and polymerization; The prepolymerization comprises firstly performing a prepolymerization reaction on diisocyanate A and polyol B to obtain prepolymer C; The polymerization includes adding the chain extender to the prepolymer C and then performing a polymerization reaction to prepare a modified polyurethane with antibacterial and antifungal properties; The prepolymer C contains a structural unit as shown in formula (III), and the end group at one or both ends contains -N=C=O; Wherein, R1 and two adjacent amide bonds or isocyanate bonds are derived from diisocyanate A; R2 and two adjacent -O- bonds are derived from polyol B; n is a positive integer, which depends on the average molecular weight of the polyol B; x is a positive integer ranging from 1 to 20.

5. The preparation method according to claim 3, characterized in that: When the bio-based chain extender E is 2,5-furandicarboxaldehyde dioxime, the synthesized modified polyurethane contains a structural unit represented by formula (IV): When the bio-based chain extender E is 5-hydroxymethyl-2-furancarbaldehyde oxime, the synthesized polyurethane contains a structural unit represented by formula (V): Wherein, R1 and two adjacent amide bonds are derived from diisocyanate A; R2 and two adjacent -O- bonds are derived from polyol B; n is a positive integer, which depends on the average molecular weight of the polyol B; x is a positive integer from 1 to 20; m is a positive integer ranging from 3 to 10.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The chain extender also includes a chain extender D; The modified polyurethane is synthesized from diisocyanate A, polyol B, chain extender D, and bio-based chain extender E; The chain extender D is C2~C 12 Saturated polyols; The synthesized modified polyurethane contains structural units represented by formula (VI) and formula (VII): Among them, R1 and two adjacent amide bonds are derived from diisocyanate A; R2 and two adjacent -O- bonds are derived from polyol B; R3 and adjacent -O- bonds are derived from the chain extender D; n is a positive integer, which depends on the average molecular weight of polyol B; m is a positive integer of 3 to 10; x is a positive integer of 1 to 20; y is a positive integer of 1 to 20; and z is a positive integer of 0 to 10. Preferably, the chain extender D comprises one or a combination of ethylene glycol, butanediol, pentanediol, hexanediol, octanediol, decanediol and dodecanediol.

7. The preparation method according to claim 6, characterized in that: A catalyst is added to the diisocyanate A and the polyol B to perform a prepolymerization reaction, wherein the molar ratio of the diisocyanate A to the polyol B is 1 to 3:1; The reaction temperature in the prepolymerization step is 50-80°C, the reaction time is 1-8 hours, preferably 2-5 hours, and the reaction gas atmosphere is an inert gas; The catalyst in the prepolymerization step is a tin-containing catalyst, including stannous octoate, octyltin maleate, dibutyltin diacetate, and monobutyltin triisooctoate; and / or, the catalyst comprises a titanium-containing catalyst, including tetrabutyl titanate; and / or, the catalyst comprises an antimony-containing catalyst, including antimony glycol and antimony acetate; The amount of the catalyst is 0.005-0.3% of the total mass of the diisocyanate A and the polyol B; and / or, the molar ratio of the bio-based chain extender E to the diisocyanate A is 0.1 to 3:1, preferably, the molar ratio of the bio-based chain extender E to the diisocyanate A is 0.5 to 2:1; and / or, the molar ratio of the chain extender D to the diisocyanate A is 0 to 2:1, preferably, the molar ratio of the chain extender D to the diisocyanate A is 0 to 1.5:1; And / or, after adding the bio-based chain extender E in the polymerization, the reaction temperature is 50-100° C., the reaction time is 2-10 hours, the reaction gas atmosphere is an inert gas, and after the reaction is completed, a modified polyurethane solution is obtained; Preferably, the polymerization further comprises adding a dispersant F, wherein the dispersant F comprises any one of methanol, ethanol, toluene, tetrahydrofuran, dichloromethane, chloroform or a combination thereof; the amount of the dispersant is 5 to 50% of the total mass of the reactants in the polymerization reaction system; and / or, the modified polyurethane solution is desolvated to obtain the modified polyurethane; The desolvation method includes any one of rotary evaporation, vacuum drying, plate heating, and water bath nitrogen blowing; the desolvation temperature is 60-120°C.

8. The preparation method according to any one of claims 3 to 5, characterized in that: The diisocyanate A is selected from one or a combination of hexamethylene diisocyanate, L-lysine diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, trans-1,4-cyclohexane diisocyanate, and dicyclohexylmethane 4,4′-diisocyanate; And / or, the polyol B is selected from one or a combination of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone glycol, polybutadiene glycol; And / or, the molecular weight of the polyol is in the range of 400 to 10000 g / mol, preferably 800 to 4000 g / mol.

9. A modified polyurethane prepared by the preparation method according to any one of claims 3 to 8; the modified polyurethane can inhibit and / or kill bacteria and fungi; the bacteria include Escherichia coli and Staphylococcus aureus; the fungi include Aspergillus niger, Chaetomium globosum, Penicillium funiculum, Paecilomyces variotii, and Trichoderma longibrachiatum.

10. Use of the modified polyurethane as claimed in claim 9 as an antibacterial and anti-mildew material in the fields of medical materials, personal protective equipment and aseptic packaging.

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