Ultrathin composite polyurethane adhesive tape with excellent waterproofness and preparation method thereof

Abstract

The invention discloses an ultrathin composite polyurethane adhesive tape with excellent waterproofness and a preparation method thereof, and relates to the technical field of polyurethane. According to the preparation method, diisocyanate and polyether polyol react to obtain a prepolymer, perfluoropolyether glycol is taken as a chain extender to react with an isocyanate group in the prepolymer, and a fluorine-containing chain segment is introduced, so that the surface free energy of the prepared hydrophobic polyurethane is reduced; then blending and compounding the hydrophobic polyurethane and the modified nano cellulose, so as to prepare composite polyurethane; and further taking the composite polyurethane as an adhesive layer, and adhering the composite polyurethane to a base material to prepare the ultrathin composite polyurethane adhesive tape with the thickness range of 0.1-0.5 mm. The ultrathin composite polyurethane adhesive tape has excellent waterproofness, and has wide application value in the aspects of medical adhesive tapes, sports adhesive tapes and the like.

Description

Technical Field

[0001] The present application relates to the technical field of polyurethane, and in particular to an ultra-thin composite polyurethane tape with excellent waterproofness and a preparation method thereof. Background Art

[0002] In modern industry and daily life, adhesive tape is an important bonding tool and is widely used in various fields. Traditional adhesive tape adhesive materials mainly include rubber-based adhesives, acrylic-based adhesives, silicone adhesives and polyurethane adhesives. Among them, polyurethane adhesives have excellent bonding properties, good flexibility and elasticity, and wide temperature adaptability. Therefore, they have gradually replaced some traditional materials in some high-end applications.

[0003] Currently, most common polyurethane tapes are compounded or modified with polyacrylates, epoxy resins, etc., and the waterproofing treatment is relatively simple. There are very few polyurethane tapes that introduce perfluoropolyether segments with high fluorine content into the polyurethane molecular chain and perform blending and compounding.

[0004] A Chinese patent with publication number CN 105368338A discloses a method for preparing a polyurethane protective tape, which is composed of a hydroxyl-terminated polyurethane elastic film with a thickness of 0.3 to 0.5 mm, a 5168 primer with a thickness of 3 μm, a polyacrylate pressure-sensitive adhesive with a thickness of 0.07 to 0.09 mm, and an anti-adhesive release paper in sequence; the 5168 primer is coated on the polyurethane elastic film, the polyacrylate pressure-sensitive adhesive is coated on the anti-adhesive release paper, and then the two adhesive surfaces are laminated together to form the polyurethane protective tape.

[0005] However, the polyurethane protective tape is simply formed by laminating components such as polyurethane and polyacrylate pressure-sensitive adhesive, without modifying the polyurethane or further blending and compounding it. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present application provides an ultra-thin composite polyurethane tape with excellent waterproofness and a preparation method thereof, wherein a hydrophobic polyurethane is prepared by introducing a perfluoropolyether segment with a high fluorine content into a polyurethane molecular chain, and the hydrophobic polyurethane is blended and compounded with modified nanocellulose to obtain a composite polyurethane; the composite polyurethane is further used as an adhesive layer and bonded to a substrate to obtain an ultra-thin composite polyurethane tape with a thickness ranging from 0.1 to 0.5 mm. The ultra-thin composite polyurethane tape has excellent waterproofness and has broad application value in medical tapes, sports tapes, and the like.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions: In the first aspect, the present application provides an ultra-thin composite polyurethane tape with excellent waterproof properties, the composite polyurethane tape comprising a substrate and an adhesive layer bonded to one side of the substrate; the substrate comprises any one of a non-woven fabric and a stretch fabric; the adhesive layer comprises a composite polyurethane; the composite polyurethane is formed by blending and compounding a hydrophobic polyurethane and modified nanocellulose; the hydrophobic polyurethane is formed by reacting a polyether polyol with a diisocyanate, and then further reacting with a perfluoropolyether diol as a chain extender.

[0008] In a second aspect, the present application provides a method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness, comprising: First, remove water from the polyether polyol, then add the polyether polyol dissolved in an organic solvent into the reactor, heat it to 60-80°C under nitrogen protection, then add diisocyanate and start stirring; Then, a catalyst is added to the reactor, and the reaction is stirred at this temperature for 2 to 4 hours to obtain a prepolymer; Then, perfluoropolyether diol was added into the prepolymer as a chain extender, and the reaction was continued at 60-80°C for 6-8h under nitrogen protection to obtain a hydrophobic polyurethane. Then, the modified nanocellulose is added to the hydrophobic polyurethane, and the mixture is blended and compounded at 60-80° C. under nitrogen protection for 1-2 hours, and the composite polyurethane is obtained by cooling and discharging the mixture; Finally, the composite polyurethane is used as an adhesive layer, adhered to the substrate, and dried at 50-60°C to obtain an ultra-thin composite polyurethane tape.

[0009] Beneficial technical effects: The present invention introduces a perfluoropolyether segment with a high fluorine content into a polyurethane molecular chain by using perfluoropolyether diol as a chain extender to react with an isocyanate group in a prepolymer. Since fluorine is the element with the strongest electronegativity, the carbon-fluorine bond energy in the perfluoropolyether segment is very high and very stable, and the fluorine atom has a shielding and protective effect on the carbon chain, so the surface free energy of the prepared hydrophobic polyurethane can be reduced, and the wettability of the surface of the hydrophobic polyurethane can be reduced, thereby achieving a waterproof effect.

[0010] Furthermore, the hydrophobic polyurethane is blended and compounded with modified nanocellulose to obtain a composite polyurethane; the modified nanocellulose has better hydrophobicity and can be better dispersed in the hydrophobic polyurethane, so the waterproofness of the obtained composite polyurethane is further enhanced.

[0011] The composite polyurethane is used as an adhesive layer, bonded to a substrate, and dried to obtain an ultra-thin composite polyurethane tape with a thickness ranging from 0.1 to 0.5 mm. The tape has excellent waterproof properties and has broad application value in medical tapes, sports tapes, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of an ultra-thin composite polyurethane tape with excellent waterproofness.

[0013] Figure 2 It is a schematic diagram of the process of preparing an ultra-thin composite polyurethane tape with excellent waterproofness.

[0014] Figure 3 It is a schematic diagram of the chemical reaction process for preparing hydrophobic polyurethane.

[0015] Figure 4 It is the general chemical structure formula of hydrophobic polyurethane.

[0016] Figure 5 is the chemical structural formula of the hydrophobic polyurethane prepared in Example 1.

[0017] Figure 6 This is a photograph of the water contact angle of the ultra-thin composite polyurethane tape with excellent waterproofness prepared in Example 1 of the present application.

[0018] Reference numerals: 1, adhesive layer; 2, substrate. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the embodiments. However, this should not be understood as the scope of the present application being limited to the following examples. Without departing from the above-mentioned method ideas of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0020] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the application.

[0021] As used in this application and the appended claims, the singular forms "for," "or," "a," "any," "any one," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] The terms “first” and “second”, if used, are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0023] In the first aspect, the present application provides an ultra-thin composite polyurethane tape with excellent waterproofness, the composite polyurethane tape comprising a substrate 2 and an adhesive layer 1 bonded to one side of the substrate 2, the specific structure of which is as follows Figure 1As shown; the substrate 2 includes any one of non-woven fabric and stretch fabric; the adhesive layer 1 includes composite polyurethane; the composite polyurethane is formed by blending and compounding hydrophobic polyurethane and modified nanocellulose; the hydrophobic polyurethane is formed by reacting polyether polyol with diisocyanate, and further reacting with perfluoropolyether diol as a chain extender.

[0024] Preferably, the thickness of the ultra-thin composite polyurethane tape is in the range of 0.1 to 0.5 mm; in the composite polyurethane, the mass ratio of hydrophobic polyurethane to modified nanocellulose is (90 to 95): (5 to 10).

[0025] Preferably, the modified nanocellulose is nanocellulose modified by a silane coupling agent; the silane coupling agent includes any one of octyltriethoxysilane, dodecyltriethoxysilane, and hexadecyltrimethoxysilane; and the average particle size of the nanocellulose is 50-200 nm.

[0026] Preferably, the method for preparing the modified nanocellulose comprises: First, add nanocellulose into the flask and start stirring at room temperature; Then, the silane coupling agent is added dropwise to the nanocellulose while stirring for 1 to 2 minutes; Then, the temperature is raised to 70-80° C., stirring is continued for 10-30 minutes, and the material is cooled to obtain modified nanocellulose, wherein the mass ratio of the silane coupling agent to the nanocellulose is controlled at (1-5):100.

[0027] In a second aspect, the present application provides a method for preparing an ultra-thin composite polyurethane tape having excellent waterproof properties, such as Figure 2 As shown, including: First, remove water from the polyether polyol, then add the polyether polyol dissolved in an organic solvent into the reactor, heat it to 60-80°C under nitrogen protection, then add diisocyanate and start stirring; Then, a catalyst is added to the reactor, and the reaction is stirred at this temperature for 2 to 4 hours to obtain a prepolymer; Then, perfluoropolyether diol was added into the prepolymer as a chain extender, and the reaction was continued at 60-80°C for 6-8h under nitrogen protection to obtain a hydrophobic polyurethane. Then, the modified nanocellulose is added to the hydrophobic polyurethane, and the mixture is blended and compounded at 60-80° C. under nitrogen protection for 1-2 hours, and the composite polyurethane is obtained by cooling and discharging the mixture; Finally, the composite polyurethane is used as the adhesive layer 1, adhered to the substrate 2, and dried at 50-60° C. to obtain an ultra-thin composite polyurethane tape.

[0028] Preferably, the organic solvent includes one or more of ethyl acetate and dichloromethane; the catalyst includes one or more of an organic tin catalyst, an organic bismuth catalyst and a tertiary amine catalyst.

[0029] Preferably, the general structural formula of the diisocyanate is represented by: ; The general structural formula of the polyether polyol is expressed as: ; The general structural formula of the prepolymer is expressed as: ; In the general structural formula of the above diisocyanate, the general structural formula of the polyether polyol and the general structural formula of the prepolymer, x is an integer in the range of 6 to 100; R includes one or more of the following structures: ; R' includes one or more of the following structures: .

[0030] Preferably, the structure of the perfluoropolyether diol is represented by: , Wherein, m is an integer in the range of 3 to 10; and n is an integer in the range of 3 to 10.

[0031] Preferably, during the preparation of the hydrophobic polyurethane, the chemical reaction that occurs is as follows Figure 3 As shown, the structure of the hydrophobic polyurethane is represented as Figure 4 The structure shown is as follows: Wherein, x is an integer in the range of 6 to 100; m is an integer in the range of 3 to 10; n is an integer in the range of 3 to 10; R includes one or more of the following structures: ; R' includes one or more of the following structures: .

[0032] Preferably, in the process of preparing the hydrophobic polyurethane, the mass ratio of the organic solvent, the polyether polyol, the diisocyanate, the catalyst and the perfluoropolyether diol is (30-40): (20-30): (20-30): (3-5): (10-20).

[0033] The following will specifically describe an ultra-thin composite polyurethane tape with excellent waterproofness and a preparation method thereof provided by the present application in combination with different embodiments.

[0034] Embodiment 1:

[0035] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polytetrahydrofuran, then dissolve it in ethyl acetate, add it to the reactor, heat it to 70°C under nitrogen protection, then add hexamethylene diisocyanate and start stirring; 2. Then, dimethyltin dilaurate was added into the reaction kettle, followed by stirring and reacting at 70° C. for 3 h to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 70°C for 7 hours under nitrogen protection to obtain a hydrophobic polyurethane. The chemical structure of the hydrophobic polyurethane is as follows: Figure 5 As shown; In steps 1 to 3, the mass ratio of ethyl acetate, polytetrahydrofuran, hexamethylene diisocyanate, dimethyltin dilaurate, and perfluoropolyether diol is 30:25:25:5:15; 4. The hydrophobic polyurethane and the modified nanocellulose are then blended and compounded at 70° C. under nitrogen protection for 1.5 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 95:5; the nanocellulose is modified with octyl triethoxy silane, and the mass ratio of octyl triethoxy silane to nanocellulose is 3:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0036] The ultra-thin composite polyurethane tape has excellent waterproofness, and its water contact angle reaches 152°. Figure 6 shown.

[0037] Embodiment 2:

[0038] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polypropylene glycol, then dissolve it in dichloromethane, add it to the reactor, heat it to 60°C under nitrogen protection, then add p-phenylene diisocyanate and start stirring; 2. Then, bismuth neodecanoate was added into the reaction kettle, and then stirred and reacted at 60° C. for 4 hours to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 60° C. for 8 h under nitrogen protection to obtain a hydrophobic polyurethane; In steps 1 to 3, the mass ratio of dichloromethane, polypropylene glycol, p-phenylene diisocyanate, bismuth neodecanoate, and perfluoropolyether diol is 35:20:30:3:12; 4. The hydrophobic polyurethane is then blended and compounded with the modified nanocellulose at 60° C. under nitrogen protection for 2 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 90:10; nanocellulose is modified with dodecyltriethoxysilane, and the mass ratio of dodecyltriethoxysilane to nanocellulose is 5:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 60° C. to obtain an ultra-thin composite polyurethane tape.

[0039] Embodiment 3:

[0040] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polyethylene oxide, then dissolve it in ethyl acetate, add it to the reactor, heat it to 80°C under nitrogen protection, then add toluene diisocyanate and start stirring; 2. Then, N,N-dimethylcyclohexylamine was added into the reaction kettle, followed by stirring and reacting at 80° C. for 2 h to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 80°C for 6 hours under nitrogen protection to obtain a hydrophobic polyurethane; In steps 1 to 3, the mass ratio of ethyl acetate, polyethylene oxide, toluene diisocyanate, N,N-dimethylcyclohexylamine, and perfluoropolyether diol is 30:30:20:3:17; 4. The hydrophobic polyurethane and the modified nanocellulose are then blended and compounded at 80° C. under nitrogen protection for 1 hour, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 92:8; the nanocellulose is modified with hexadecyltrimethoxysilane, and the mass ratio of hexadecyltrimethoxysilane to nanocellulose is 2:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 50° C. to obtain an ultra-thin composite polyurethane tape.

[0041] Embodiment 4:

[0042] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polytetrahydrofuran, then dissolve it in dichloromethane, add it to the reactor, heat it to 75°C under nitrogen protection, then add diphenylmethane diisocyanate, and start stirring; 2. Then, dibutyltin dilaurate was added into the reaction kettle, followed by stirring and reacting at 75° C. for 3 hours to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 75°C for 7 hours under nitrogen protection to obtain a hydrophobic polyurethane; In steps 1 to 3, the mass ratio of dichloromethane, polytetrahydrofuran, diphenylmethane diisocyanate, dibutyltin dilaurate, and perfluoropolyether diol is 30:28:22:3:17; 4. The hydrophobic polyurethane and the modified nanocellulose are then blended and compounded at 75° C. under nitrogen protection for 1.5 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 94:6; the nanocellulose is modified with octyl triethoxy silane, and the mass ratio of octyl triethoxy silane to nanocellulose is 1:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0043] Embodiment 5:

[0044] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polypropylene glycol, then dissolve it in ethyl acetate, add it to the reactor, heat it to 60°C under nitrogen protection, then add isophorone diisocyanate, and start stirring; 2. Then, bismuth 2-ethylhexanoate was added to the reaction kettle, and then stirred at 60° C. for 4 hours to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 60° C. for 8 h under nitrogen protection to obtain a hydrophobic polyurethane; In steps 1 to 3, the mass ratio of ethyl acetate, polypropylene glycol, isophorone diisocyanate, bismuth 2-ethylhexanoate, and perfluoropolyether diol is 30:28:22:3:17; 4. The hydrophobic polyurethane is then blended and compounded with the modified nanocellulose at 60° C. under nitrogen protection for 2 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 91:9; nanocellulose is modified with dodecyltriethoxysilane, and the mass ratio of dodecyltriethoxysilane to nanocellulose is 4:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0045] Embodiment 6:

[0046] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polyethylene oxide, then dissolve it in dichloromethane, add it to the reactor, heat it to 80°C under nitrogen protection, then add toluene diisocyanate and start stirring; 2. Then, triethylenediamine was added into the reaction kettle, followed by stirring and reacting at 80° C. for 2 h to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 80°C for 6 hours under nitrogen protection to obtain a hydrophobic polyurethane; In steps 1 to 3, the mass ratio of dichloromethane, polyethylene oxide, toluene diisocyanate, triethylenediamine, and perfluoropolyether diol is 30:25:27:3:15; 4. The hydrophobic polyurethane and the modified nanocellulose are then blended and compounded at 80° C. under nitrogen protection for 1 hour, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 93:7; the nanocellulose is modified with hexadecyltrimethoxysilane, and the mass ratio of hexadecyltrimethoxysilane to nanocellulose is 4:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 50° C. to obtain an ultra-thin composite polyurethane tape.

[0047] Comparative Example 1: A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polytetrahydrofuran, then dissolve it in ethyl acetate, add it to the reactor, heat it to 70°C under nitrogen protection, then add hexamethylene diisocyanate and start stirring; 2. Then, dimethyltin dilaurate was added into the reaction kettle, followed by stirring and reacting at 70° C. for 3 h to obtain a prepolymer; 3. Then 1,4-butanediol was added to the prepolymer, and the reaction was continued at 70°C for 7 hours under nitrogen protection to obtain a hydrophobic polyurethane. The chemical structure of the hydrophobic polyurethane is as follows: Figure 5 As shown; In steps 1 to 3, the mass ratio of ethyl acetate, polytetrahydrofuran, hexamethylene diisocyanate, dimethyltin dilaurate, and 1,4-butanediol is 30:25:25:5:15; 4. The hydrophobic polyurethane and the modified nanocellulose are then blended and compounded at 70° C. under nitrogen protection for 1.5 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to modified nanocellulose is 95:5; the nanocellulose is modified with octyl triethoxy silane, and the mass ratio of octyl triethoxy silane to nanocellulose is 3:100; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0048] Comparative Example 2: A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polytetrahydrofuran, then dissolve it in ethyl acetate, add it to the reactor, heat it to 70°C under nitrogen protection, then add hexamethylene diisocyanate and start stirring; 2. Then, dimethyltin dilaurate was added into the reaction kettle, followed by stirring and reacting at 70° C. for 3 h to obtain a prepolymer; 3. Then, perfluoropolyether diol was added to the prepolymer as a chain extender, and the reaction was continued at 70°C for 7 hours under nitrogen protection to obtain a hydrophobic polyurethane. The chemical structure of the hydrophobic polyurethane is as follows: Figure 5 As shown; In steps 1 to 3, the mass ratio of ethyl acetate, polytetrahydrofuran, hexamethylene diisocyanate, dimethyltin dilaurate, and perfluoropolyether diol is 30:25:25:5:15; 4. The hydrophobic polyurethane and the nanocellulose are then blended and compounded at 70° C. under nitrogen protection for 1.5 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to nanocellulose is 95:5; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0049] Comparative Example 3: A method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness comprises the following steps: 1. First, remove water from polytetrahydrofuran, then dissolve it in ethyl acetate, add it to the reactor, heat it to 70°C under nitrogen protection, then add hexamethylene diisocyanate and start stirring; 2. Then, dimethyltin dilaurate was added into the reaction kettle, followed by stirring and reacting at 70° C. for 3 h to obtain a prepolymer; 3. Then 1,4-butanediol was added to the prepolymer, and the reaction was continued at 70°C for 7 hours under nitrogen protection to obtain a hydrophobic polyurethane. The chemical structure of the hydrophobic polyurethane is as follows: Figure 5 As shown; In steps 1 to 3, the mass ratio of ethyl acetate, polytetrahydrofuran, hexamethylene diisocyanate, dimethyltin dilaurate, and 1,4-butanediol is 30:25:25:5:15; 4. The hydrophobic polyurethane and the nanocellulose are then blended and compounded at 70° C. under nitrogen protection for 1.5 hours, and the composite polyurethane is obtained by cooling and discharging; The mass ratio of hydrophobic polyurethane to nanocellulose is 95:5; 5. Finally, the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried at 55°C to obtain an ultra-thin composite polyurethane tape.

[0050] With reference to YY / T0471.3-2004, the water barrier test method is adopted to reflect the waterproofness of the ultra-thin composite polyurethane tape by testing the time it withstands 500mm static water pressure.

[0051] Referring to GB / T30693-2014, the water contact angle of the ultra-thin composite polyurethane tape was tested using a contact angle meter to reflect its waterproofness.

[0052] Table 1 Waterproof test results of ultra-thin composite polyurethane tapes prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0053] As can be seen from Table 1, Examples 1 to 6 can withstand a 500 mm hydrostatic pressure for more than 300 seconds, and the water contact angles are all greater than 150°, while Examples 1 to 3 have water contact angles far less than 150°, and withstand a 500 mm hydrostatic pressure for less than 300 seconds. This is because Examples 1 to 6 all use perfluoropolyether diols as chain extenders to react with isocyanate groups in prepolymers, and introduce perfluoropolyether segments with high fluorine content into polyurethane molecular chains. Since fluorine is the element with the strongest electronegativity, the carbon-fluorine bond energy in the perfluoropolyether segment is very high and very stable, and the fluorine atom has a shielding and protective effect on the carbon chain, so the surface free energy of the obtained hydrophobic polyurethane can be reduced, and the wettability of the surface of the hydrophobic polyurethane can be reduced, thereby achieving a waterproof effect.

[0054] Furthermore, in Examples 1 to 6, hydrophobic polyurethane and modified nanocellulose are blended and compounded to obtain composite polyurethane; the modified nanocellulose has good hydrophobicity and can be better dispersed in the hydrophobic polyurethane, so the waterproofness of the obtained composite polyurethane is further enhanced; the composite polyurethane is used as the adhesive layer 1, bonded to the substrate 2, and dried to obtain an ultra-thin composite polyurethane tape, so that the tape has excellent waterproofness.

[0055] Comparative Examples 1 to 3 either do not introduce perfluoropolyether segments (Comparative Example 1), or do not blend with modified nanocellulose (Comparative Example 2), or do not have either (Comparative Example 3). Therefore, their water resistance is poor, and they cannot withstand a hydrostatic pressure of 500 mm for 300 seconds, and their water contact angles are also small.

[0056] The above results show and describe the basic principles and main features of the present application as well as the advantages of the present application.

[0057] Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection sought in the present application is defined by the equivalents of the attached claims.

Claims

1. An ultra-thin composite polyurethane tape with excellent waterproofness, characterized in that: The ultra-thin composite polyurethane tape comprises a substrate (2) and an adhesive layer (1) bonded to one side of the substrate (2); the substrate (2) comprises any one of a non-woven fabric and a stretch fabric; the adhesive layer (1) comprises a composite polyurethane; the composite polyurethane is formed by blending and compounding a hydrophobic polyurethane and modified nanocellulose; the hydrophobic polyurethane is formed by reacting a polyether polyol with a diisocyanate, and then further reacting with a perfluoropolyether diol as a chain extender.

2. The ultra-thin composite polyurethane tape with excellent waterproofness according to claim 1, characterized in that: The thickness of the ultra-thin composite polyurethane tape ranges from 0.1 to 0.5 mm; in the composite polyurethane, the mass ratio of hydrophobic polyurethane to modified nanocellulose is (90 to 95): (5 to 10).

3. The ultra-thin composite polyurethane tape with excellent waterproofness according to claim 1, characterized in that: The modified nanocellulose is nanocellulose modified by a silane coupling agent; the silane coupling agent includes any one of octyltriethoxysilane, dodecyltriethoxysilane, and hexadecyltrimethoxysilane; and the average particle size of the nanocellulose is 50-200 nm.

4. The ultra-thin composite polyurethane tape with excellent waterproofness according to claim 3, characterized in that: The preparation method of the modified nanocellulose comprises: First, add nanocellulose into the flask and start stirring at room temperature; Then, the silane coupling agent is added dropwise to the nanocellulose while stirring for 1 to 2 minutes; Then, the temperature is raised to 70-80° C., stirring is continued for 10-30 minutes, and the material is cooled to obtain modified nanocellulose, wherein the mass ratio of the silane coupling agent to the nanocellulose is controlled at (1-5):

100.

5. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to any one of claims 1 to 4, characterized in that: The following steps are involved: First, remove water from the polyether polyol, then add the polyether polyol dissolved in an organic solvent into the reactor, heat it to 60-80°C under nitrogen protection, then add diisocyanate and start stirring; Then, a catalyst is added to the reactor, and the reaction is stirred at this temperature for 2 to 4 hours to obtain a prepolymer; Then, perfluoropolyether diol was added into the prepolymer as a chain extender, and the reaction was continued at 60-80°C for 6-8h under nitrogen protection to obtain a hydrophobic polyurethane. Then, the modified nanocellulose is added to the hydrophobic polyurethane, and the mixture is blended and compounded at 60-80° C. under nitrogen protection for 1-2 hours, and the composite polyurethane is obtained by cooling and discharging the mixture; Finally, the composite polyurethane is used as an adhesive layer (1), bonded to the substrate (2), and dried at 50-60° C. to obtain an ultra-thin composite polyurethane tape.

6. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to claim 5, characterized in that: The organic solvent includes one or both of ethyl acetate and dichloromethane; the catalyst includes one or more of an organic tin catalyst, an organic bismuth catalyst and a tertiary amine catalyst.

7. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to claim 5, characterized in that: The general structural formula of the diisocyanate is expressed as: ， The general structural formula of the polyether polyol is expressed as: ， The general structural formula of the prepolymer is expressed as: ， In the general structural formula of the diisocyanate, the general structural formula of the polyether polyol and the general structural formula of the prepolymer, x is an integer in the range of 6 to 100; R includes one or more of the following structures: ； R' includes one or more of the following structures: 。 8. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to claim 5, characterized in that: The structure of the perfluoropolyether diol is represented by: ， Wherein, m is an integer in the range of 3 to 10; and n is an integer in the range of 3 to 10.

9. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to claim 5, characterized in that: The structure of the hydrophobic polyurethane is represented as: Wherein, x is an integer in the range of 6 to 100; m is an integer in the range of 3 to 10; n is an integer in the range of 3 to 10; R includes one or more of the following structures: ； R' includes one or more of the following structures: 。 10. The method for preparing an ultra-thin composite polyurethane tape with excellent waterproofness according to claim 5, characterized in that: In the process of preparing hydrophobic polyurethane, the mass ratio of the organic solvent, polyether polyol, diisocyanate, catalyst and perfluoropolyether diol is (30-40): (20-30): (20-30): (3-5): (10-20).

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