An ultra-thin composite polyurethane tape with excellent waterproof property and its preparation method

Abstract

The present application discloses an ultra-thin composite polyurethane tape with excellent waterproof property and its preparation method, which relates to the technical field of polyurethane. In this application, a prepolymer is obtained by reacting a diisocyanate and a polyether polyol, and then a perfluoropolyether diol is used as a chain extender to react with the isocyanate groups in the prepolymer, introducing a fluorine-containing segment, thereby reducing the surface free energy of the prepared hydrophobic polyurethane; then the hydrophobic polyurethane is blended and compounded with modified nanocellulose to obtain a composite polyurethane; further, the composite polyurethane is used as an adhesive layer and adhered to a substrate to obtain an ultra-thin composite polyurethane tape with a thickness range of 0.1 to 0.5 mm. The ultra-thin composite polyurethane tape has excellent waterproof property and has broad application value in aspects such as medical tapes and sports tapes.

Description

Technical Field

[0001] This application relates to the technical field of polyurethanes, and specifically relates to an ultra-thin composite polyurethane tape with excellent waterproof properties and a preparation method thereof. Background Art

[0002] In modern industry and daily life, as an important bonding tool, tapes are widely used in various fields. The adhesive layer materials of traditional tapes mainly include rubber-based adhesives, acrylic-based adhesives, silicone adhesives, and polyurethane adhesives. Among them, polyurethane adhesives have the advantages of excellent bonding performance, good flexibility and elasticity, and wide temperature adaptability, etc. Therefore, they have gradually replaced some traditional materials in some high-end applications.

[0003] Currently, common polyurethane tapes mostly use polyacrylate, epoxy resin, etc. for compounding or modification. The waterproof treatment is relatively simple, and there are few polyurethane tapes that introduce perfluoropolyether chain segments with a high fluorine content into the polyurethane molecular chain and carry out blending and compounding.

[0004] Chinese Patent with Publication No. CN 105368338A discloses a preparation method of a polyurethane protective tape. The polyurethane protective tape is successively composed of a hydroxyl-terminated polyurethane elastic film with a thickness of 0.3 - 0.5 mm, a 3 - μm 5168 primer, a polyacrylate pressure-sensitive adhesive with a thickness of 0.07 - 0.09 mm, and a release paper. The 5168 primer is coated on the polyurethane elastic film, the polyacrylate pressure-sensitive adhesive is coated on the release paper, and then the two adhesive surfaces are laminated together to make the polyurethane protective tape.

[0005] However, this polyurethane protective tape only simply laminates components such as polyurethane and polyacrylate pressure-sensitive adhesive, and does not carry out modification treatment or further blending and compounding on the polyurethane. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, this application provides an ultra-thin composite polyurethane tape with excellent waterproof properties and a preparation method thereof. Hydrophobic polyurethane with perfluoropolyether chain segments with a high fluorine content introduced into the polyurethane molecular chain is prepared, and it is blended and compounded with modified nanocellulose to obtain composite polyurethane. Further, the composite polyurethane is used as the adhesive layer and adhered to a substrate to obtain an ultra-thin composite polyurethane tape with a thickness range of 0.1 - 0.5 mm. This ultra-thin composite polyurethane tape has excellent waterproof properties and has broad application value in medical tapes, sports tapes, etc.

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

[0008] In a first aspect, the present application provides an ultra-thin composite polyurethane tape with excellent waterproof properties. The ultra-thin composite polyurethane tape includes a substrate and an adhesive layer bonded to one side of the substrate; the substrate includes any one of non-woven fabric and elastic fabric; the adhesive layer includes composite polyurethane; the composite polyurethane is formed by blending and compounding hydrophobic polyurethane and modified nano-cellulose; the hydrophobic polyurethane is formed by reacting polyether polyol with diisocyanate and further reacting with perfluoropolyether diol as a chain extender;

[0009] The structural general formula of the diisocyanate is represented as:

[0010] ,

[0011] The structural general formula of the polyether polyol is represented as:

[0012] ,

[0013] The structural general formula of the prepolymer is represented as:

[0014] ,

[0015] In the structural general formula of the polyether polyol and the prepolymer, x is an integer in the range of 6 to 100;

[0016] R includes one or more of the following structures:

[0017] , , , , ;

[0018] R' includes one or more of the following structures:

[0019] , , ;

[0020] The structure of the perfluoropolyether diol is represented as:

[0021] ,

[0022] wherein, m is an integer in the range of 3 to 10; n is an integer in the range of 3 to 10;

[0023] The structure of the hydrophobic polyurethane is represented as:

[0024]

[0025] 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;

[0026] R comprises one or more of the following structures:

[0027] , , , , ;

[0028] R' comprises one or more of the following structures: , , .

[0029] In a second aspect, the present application provides a method for preparing an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising:

[0030] First, dehydrate the polyether polyol, then add the polyether polyol dissolved in an organic solvent to a reaction kettle, heat it to 60-80 °C under nitrogen protection, and then add the diisocyanate and start stirring;

[0031] Subsequently, add a catalyst to the reaction kettle, and then stir and react at this temperature for 2-4 h to obtain a prepolymer;

[0032] Then add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 60-80 °C under nitrogen protection for 6-8 h to prepare a hydrophobic polyurethane;

[0033] Next, add the modified nanocellulose to the hydrophobic polyurethane, and carry out blending and compounding at 60-80 °C under nitrogen protection for 1-2 hours, and then cool and discharge to obtain the composite polyurethane;

[0034] Finally, use the composite polyurethane as an adhesive layer, bond it to a substrate, and dry it at 50-60 °C to obtain the ultra-thin composite polyurethane tape.

[0035] Beneficial technical effects:

[0036] In the present application, perfluoropolyether diol is used as a chain extender to react with the isocyanate groups in the prepolymer, introducing perfluoropolyether chain segments with a high fluorine content into the polyurethane molecular chain. Since fluorine is the element with the strongest electronegativity, the carbon-fluorine bond energy in the perfluoropolyether chain segments is very high and very stable, and the fluorine atoms have a shielding and protective effect on the carbon chain. Therefore, 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.

[0037] Furthermore, the hydrophobic polyurethane is blended and compounded with the modified nanocellulose to obtain the composite polyurethane; the nanocellulose has better hydrophobicity after modification and can be better dispersed in the hydrophobic polyurethane. Therefore, the waterproof performance of the prepared composite polyurethane is further enhanced.

[0038] The composite polyurethane is used as an adhesive layer and adhered to a substrate, and then dried to obtain an ultra-thin composite polyurethane tape with a thickness range of 0.1-0.5 mm. This tape has excellent waterproof performance and has broad application value in medical tapes, sports tapes, etc. Brief Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of an ultra-thin composite polyurethane tape with excellent waterproof performance.

[0040] Figure 2 It is a schematic process diagram for preparing an ultra-thin composite polyurethane tape with excellent waterproof performance.

[0041] Figure 3 It is a schematic diagram of the chemical reaction process for preparing hydrophobic polyurethane.

[0042] Figure 4 It is the chemical structural formula of the hydrophobic polyurethane prepared in Example 1.

[0043] Figure 5 It is a photo of the water contact angle of the ultra-thin composite polyurethane tape with excellent waterproof performance prepared in Example 1 of this application.

[0044] Reference Signs: 1. Adhesive layer; 2. Substrate. Detailed Description of the Embodiments

[0045] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer, the present application will be further described in detail below in conjunction with the embodiments. However, it should not be understood that the scope of this application is limited to the following examples. Without departing from the above-mentioned method concept of this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0046] In this application, the terms used are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0047] The singular forms of "is", "or", "a", "any one", "any kind" and "the" used in this application and the appended claims are intended to include the plural forms unless the context clearly indicates otherwise.

[0048] When terms such as "first" and "second" appear, they are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0049] In a first aspect, this application provides an ultra-thin composite polyurethane tape with excellent waterproof performance. The ultra-thin composite polyurethane tape includes a substrate 2 and an adhesive layer 1 adhered to one side of the substrate 2. The specific structure is asFigure 1 As shown; the substrate 2 includes any one of non-woven fabric and elastic fabric; the adhesive layer 1 includes composite polyurethane; the composite polyurethane is formed by blending and compounding hydrophobic polyurethane and modified nano-cellulose; the hydrophobic polyurethane is formed by reacting polyether polyol with diisocyanate and further reacting with perfluoropolyether diol as a chain extender;

[0050] The structural general formula of the diisocyanate is represented as:

[0051] ,

[0052] The structural general formula of the polyether polyol is represented as:

[0053] ,

[0054] The structural general formula of the prepolymer is represented as:

[0055] ,

[0056] In the structural general formula of the polyether polyol and the structural general formula of the prepolymer, x is an integer in the range of 6 to 100;

[0057] R includes one or more of the following structures:

[0058] , , , , ;

[0059] R' includes one or more of the following structures:

[0060] , , ;

[0061] The structure of the perfluoropolyether diol is represented as:

[0062] ,

[0063] wherein, m is an integer in the range of 3 to 10; n is an integer in the range of 3 to 10;

[0064] The structure of the hydrophobic polyurethane is represented as:

[0065]

[0066] 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;

[0067] R includes one or more of the following structures:

[0068] 、 、 、 、 ;

[0069] R' includes one or more of the following structures: 、 、 。

[0070] Preferably, the thickness range of the ultra-thin composite polyurethane tape is 0.1 - 0.5 mm; in the composite polyurethane, the mass ratio of the hydrophobic polyurethane to the modified nanocellulose is (90 - 95):(5 - 10).

[0071] Preferably, the modified nanocellulose is nanocellulose modified by a silane coupling agent; the silane coupling agent includes any one of octyltriethoxysilane, dodecyltriethoxysilane, and hexadecyltrimethoxysilane; the average particle size of the nanocellulose is 50 - 200 nm.

[0072] Preferably, the preparation method of the modified nanocellulose includes:

[0073] First, add the nanocellulose to a flask and start stirring at room temperature;

[0074] Then, dropwise add the silane coupling agent to the nanocellulose while stirring, and the dropping time is 1 - 2 min;

[0075] Next, raise the temperature to 70 - 80 °C, continuously stir for 10 - 30 min, discharge and cool to obtain the modified nanocellulose, wherein the mass ratio of the silane coupling agent to the nanocellulose is controlled at (1 - 5):100.

[0076] In a second aspect, the present application provides a preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance, as Figure 2 shown, including:

[0077] First, dehydrate the polyether polyol, then add the polyether polyol dissolved in an organic solvent to a reaction kettle, raise the temperature to 60 - 80 °C under nitrogen protection, and then add diisocyanate and start stirring;

[0078] Subsequently, add a catalyst to the reaction kettle, and then stir and react at this temperature for 2 - 4 h to obtain a prepolymer;

[0079] Then, add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 60 - 80 °C for 6 - 8 h under nitrogen protection to obtain hydrophobic polyurethane;

[0080] Then, the modified nanocellulose is added to the hydrophobic polyurethane, and they are blended and compounded at 60-80°C under nitrogen protection for 1-2 hours. After cooling and discharging, the composite polyurethane is obtained.

[0081] Finally, the composite polyurethane is used as adhesive layer 1 and bonded to substrate 2, and then dried at 50-60°C to obtain the ultra-thin composite polyurethane tape.

[0082] Preferably, the organic solvent includes one or more of ethyl acetate and dichloromethane; the catalyst includes one or more of organotin catalysts, organobismuth catalysts, and tertiary amine catalysts.

[0083] Preferably, during the preparation of the hydrophobic polyurethane, the chemical reaction is as Figure 3 shown.

[0084] Preferably, during the preparation of the 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).

[0085] The following will specifically describe a kind of ultra-thin composite polyurethane tape with excellent waterproof property and its preparation method provided by the present application in combination with different embodiments.

[0086] Example 1:

[0087] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof property includes the following steps:

[0088] 1. First, dehydrate polytetrahydrofuran, then dissolve it in ethyl acetate, add it to a reaction kettle, heat it to 70°C under nitrogen protection, and then add hexamethylene diisocyanate and start stirring.

[0089] 2. Subsequently, add dimethyltin dilaurate to the reaction kettle, and then stir and react at 70°C for 3 h to obtain a prepolymer.

[0090] 3. Then, add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 70°C for 7 h under nitrogen protection to obtain the hydrophobic polyurethane. The chemical structural formula of the hydrophobic polyurethane is as Figure 4 shown;

[0091] In steps 1-3, the mass ratio of ethyl acetate, polytetrahydrofuran, hexamethylene diisocyanate, dimethyltin dilaurate, and perfluoropolyether diol is 30:25:25:5:15.

[0092] 4. Then blend and compound hydrophobic polyurethane with modified nanocellulose. Under nitrogen protection, conduct the blending and compounding at 70°C for 1.5 hours, and then cool and discharge to obtain the composite polyurethane.

[0093] The mass ratio of hydrophobic polyurethane to modified nanocellulose is 95:5; the nanocellulose is modified with octyltriethoxysilane, and the mass ratio of octyltriethoxysilane to nanocellulose is 3:100.

[0094] 5. Finally, use the composite polyurethane as adhesive layer 1 and bond it to substrate 2, and dry it at 55°C to obtain the ultra-thin composite polyurethane tape.

[0095] The obtained ultra-thin composite polyurethane tape has excellent waterproof performance, and its water contact angle reaches 152°. The photo is as Figure 5 shown.

[0096] Example 2:

[0097] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising the following steps:

[0098] 1. First, dehydrate polypropylene glycol, then dissolve it in dichloromethane, add it to the reaction kettle, heat it to 60°C under nitrogen protection, and then add p-phenylene diisocyanate and start stirring.

[0099] 2. Subsequently, add bismuth neodecanoate to the reaction kettle, and then stir and react at 60°C for 4 h to obtain a prepolymer.

[0100] 3. Then add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 60°C for 8 h under nitrogen protection to obtain hydrophobic polyurethane.

[0101] In steps 1 - 3, the mass ratio of dichloromethane, polypropylene glycol, p-phenylene diisocyanate, bismuth neodecanoate, and perfluoropolyether diol is 35:20:30:3:12.

[0102] 4. Then blend and compound hydrophobic polyurethane with modified nanocellulose. Under nitrogen protection, conduct the blending and compounding at 60°C for 2 hours, and then cool and discharge to obtain the composite polyurethane.

[0103] The mass ratio of hydrophobic polyurethane to modified nanocellulose is 90:10; the nanocellulose is modified with dodecyltriethoxysilane, and the mass ratio of dodecyltriethoxysilane to nanocellulose is 5:100.

[0104] 5. Finally, use the composite polyurethane as adhesive layer 1 and bond it to substrate 2, and dry it at 60°C to obtain the ultra-thin composite polyurethane tape.

[0105] Example 3:

[0106] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof property, comprising the following steps:

[0107] 1. First, dehydrate polyethylene oxide, then dissolve it in ethyl acetate, add it to a reaction kettle, heat it to 80 °C under nitrogen protection, then add toluene diisocyanate, and start stirring;

[0108] 2. Subsequently, add N,N-dimethylcyclohexylamine to the reaction kettle, and then stir and react at 80 °C for 2 h to obtain a prepolymer;

[0109] 3. Then add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 80 °C for 6 h under nitrogen protection to prepare a hydrophobic polyurethane;

[0110] 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;

[0111] 4. Then blend and compound the hydrophobic polyurethane with modified nanocellulose, and perform blend compounding at 80 °C under nitrogen protection for 1 hour, and cool and discharge to obtain a composite polyurethane;

[0112] The mass ratio of the hydrophobic polyurethane to the modified nanocellulose is 92:8; the nanocellulose is modified with cetyltrimethoxysilane, and the mass ratio of cetyltrimethoxysilane to the nanocellulose is 2:100;

[0113] 5. Finally, use the composite polyurethane as Adhesive Layer 1, bond it to Substrate 2, and dry it at 50 °C to obtain the ultra-thin composite polyurethane tape.

[0114] Example 4:

[0115] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof property, comprising the following steps:

[0116] 1. First, dehydrate polytetrahydrofuran, then dissolve it in dichloromethane, add it to a reaction kettle, heat it to 75 °C under nitrogen protection, then add diphenylmethane diisocyanate, and start stirring;

[0117] 2. Subsequently, add dibutyltin dilaurate to the reaction kettle, and then stir and react at 75 °C for 3 h to obtain a prepolymer;

[0118] 3. Then add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 75 °C for 7 h under nitrogen protection to prepare a hydrophobic polyurethane;

[0119] In Steps 1 to 3, the mass ratio of dichloromethane, polytetrahydrofuran, diphenylmethane diisocyanate, dibutyltin dilaurate, and perfluoropolyether diol is 30:28:22:3:17;

[0120] 4. Then, blend and compound hydrophobic polyurethane and modified nanocellulose. Carry out the blend and compound at 75°C under nitrogen protection for 1.5 hours, and then cool and discharge to obtain the composite polyurethane;

[0121] The mass ratio of hydrophobic polyurethane to modified nanocellulose is 94:6; the nanocellulose is modified with octyltriethoxysilane, and the mass ratio of octyltriethoxysilane to nanocellulose is 1:100;

[0122] 5. Finally, use the composite polyurethane as Adhesive Layer 1 and bond it to Substrate 2, and dry it at 55°C to obtain the ultra-thin composite polyurethane tape.

[0123] Example 5:

[0124] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof property, comprising the following steps:

[0125] 1. First, dehydrate polypropylene glycol, then dissolve it in ethyl acetate, add it to a reaction kettle, heat it to 60°C under nitrogen protection, and then add isophorone diisocyanate and start stirring;

[0126] 2. Subsequently, add bismuth 2-ethylhexanoate to the reaction kettle, and then stir and react at 60°C for 4 h to obtain a prepolymer;

[0127] 3. Then, add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 60°C for 8 h under nitrogen protection to obtain hydrophobic polyurethane;

[0128] 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;

[0129] 4. Then, blend and compound hydrophobic polyurethane and modified nanocellulose. Carry out the blend and compound at 60°C under nitrogen protection for 2 hours, and then cool and discharge to obtain the composite polyurethane;

[0130] The mass ratio of hydrophobic polyurethane to modified nanocellulose is 91:9; the nanocellulose is modified with dodecyltriethoxysilane, and the mass ratio of dodecyltriethoxysilane to nanocellulose is 4:100;

[0131] 5. Finally, use the composite polyurethane as Adhesive Layer 1 and bond it to Substrate 2, and dry it at 55°C to obtain the ultra-thin composite polyurethane tape.

[0132] Example 6:

[0133] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising the following steps:

[0134] 1. First, dehydrate polyethylene oxide, then dissolve it in dichloromethane, add it to a reaction kettle, heat it to 80 °C under nitrogen protection, then add toluene diisocyanate, and start stirring;

[0135] 2. Subsequently, add triethylenediamine to the reaction kettle, and then stir and react at 80 °C for 2 h to obtain a prepolymer;

[0136] 3. Then add perfluoropolyether diol as a chain extender to the prepolymer, and continue to stir and react at 80 °C for 6 h under nitrogen protection to obtain hydrophobic polyurethane;

[0137] In steps 1-3, the mass ratio of dichloromethane, polyethylene oxide, toluene diisocyanate, triethylenediamine, and perfluoropolyether diol is 30:25:27:3:15;

[0138] 4. Then blend and compound the hydrophobic polyurethane with modified nanocellulose, and carry out blend and compounding at 80 °C under nitrogen protection for 1 hour, and cool and discharge to obtain composite polyurethane;

[0139] The mass ratio of the hydrophobic polyurethane to the modified nanocellulose is 93:7; the nanocellulose is modified with cetyltrimethoxysilane, and the mass ratio of cetyltrimethoxysilane to the nanocellulose is 4:100;

[0140] 5. Finally, use the composite polyurethane as adhesive layer 1, bond it to substrate 2, and dry it at 50 °C to obtain the ultra-thin composite polyurethane tape.

[0141] Comparative example 1:

[0142] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising the following steps:

[0143] 1. First, dehydrate polytetrahydrofuran, then dissolve it in ethyl acetate, add it to a reaction kettle, heat it to 70 °C under nitrogen protection, then add hexamethylene diisocyanate, and start stirring;

[0144] 2. Subsequently, add dimethyltin dilaurate to the reaction kettle, and then stir and react at 70 °C for 3 h to obtain a prepolymer;

[0145] 3. Then add 1,4-butanediol to the prepolymer, and continue to stir and react at 70 °C for 7 h under nitrogen protection to obtain hydrophobic polyurethane, and the chemical structural formula of the hydrophobic polyurethane is as Figure 5 shown;

[0146] 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;

[0147] 4. Then, blend and compound hydrophobic polyurethane and modified nanocellulose. Under nitrogen protection, conduct the blend and compound at 70°C for 1.5 hours, and then cool and discharge to obtain the composite polyurethane;

[0148] The mass ratio of hydrophobic polyurethane to modified nanocellulose is 95:5; the nanocellulose is modified with octyltriethoxysilane, and the mass ratio of octyltriethoxysilane to nanocellulose is 3:100;

[0149] 5. Finally, use the composite polyurethane as Adhesive Layer 1, bond it to Substrate 2, and dry it at 55°C to obtain the ultra-thin composite polyurethane tape.

[0150] Comparative Example 2:

[0151] A method for preparing an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising the following steps:

[0152] 1. First, dehydrate polytetrahydrofuran, then dissolve it in ethyl acetate, add it to a reaction kettle, raise the temperature to 70°C under nitrogen protection, and then add hexamethylene diisocyanate and start stirring;

[0153] 2. Subsequently, add dimethyltin dilaurate to the reaction kettle, and then stir and react at 70°C for 3 h to obtain a prepolymer;

[0154] 3. Then, add perfluoropolyether diol as a chain extender to the prepolymer, continue to stir and react at 70°C for 7 h under nitrogen protection to obtain hydrophobic polyurethane, and the chemical structural formula of the hydrophobic polyurethane is as Figure 5 shown;

[0155] 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;

[0156] 4. Then, blend and compound hydrophobic polyurethane and nanocellulose. Under nitrogen protection, conduct the blend and compound at 70°C for 1.5 hours, and then cool and discharge to obtain the composite polyurethane;

[0157] The mass ratio of hydrophobic polyurethane to nanocellulose is 95:5;

[0158] 5. Finally, use the composite polyurethane as Adhesive Layer 1, bond it to Substrate 2, and dry it at 55°C to obtain the ultra-thin composite polyurethane tape.

[0159] Comparative Example 3:

[0160] A preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance, comprising the following steps:

[0161] 1. First, dehydrate polytetrahydrofuran, then dissolve it in ethyl acetate, add it to a reaction kettle, heat it to 70 °C under nitrogen protection, then add hexamethylene diisocyanate, and start stirring;

[0162] 2. Subsequently, add dimethyltin dilaurate to the reaction kettle, and then stir and react at 70 °C for 3 h to obtain a prepolymer;

[0163] 3. Then add 1,4-butanediol to the prepolymer, continue to stir and react at 70 °C for 7 h under nitrogen protection to prepare a hydrophobic polyurethane, and the chemical structural formula of the hydrophobic polyurethane is as Figure 5 shown;

[0164] 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;

[0165] 4. Then blend and compound the hydrophobic polyurethane with nanocellulose, and carry out blend compounding at 70 °C under nitrogen protection for 1.5 hours, and cool and discharge to obtain a composite polyurethane;

[0166] The mass ratio of the hydrophobic polyurethane to the nanocellulose is 95:5;

[0167] 5. Finally, use the composite polyurethane as adhesive layer 1, bond it to substrate 2, and dry it at 55 °C to obtain the ultra-thin composite polyurethane tape.

[0168] With reference to YY / T0471.3-2004, adopt a water resistance test method, and reflect the waterproof performance by testing the time for the ultra-thin composite polyurethane tape to withstand a static water pressure of 500 mm.

[0169] With reference to GB / T30693-2014, use a contact angle measuring instrument to test the water contact angle of the ultra-thin composite polyurethane tape to reflect its waterproof performance.

[0170] Table 1 Waterproof performance test results of the ultra-thin composite polyurethane tapes prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0171]

[0172] As can be seen from Table 1, Examples 1 to 6 can all withstand a hydrostatic pressure of 500 mm for more than 300 s, and the water contact angles are all greater than 150°. For Comparative Examples 1 to 3, the water contact angles are all much less than 150°, and the hydrostatic pressure they can withstand is also less than 300 s. This is because in Examples 1 to 6, perfluoropolyether diol is used as a chain extender to react with the isocyanate groups in the prepolymer, introducing perfluoropolyether segments with a high fluorine content into the polyurethane molecular chain. Since fluorine is the element with the highest electronegativity, the carbon-fluorine bond energy in the perfluoropolyether segments is very high and very stable. Moreover, fluorine atoms have 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.

[0173] Furthermore, in Examples 1 to 6, the hydrophobic polyurethane is blended and compounded with modified nanocellulose to prepare a composite polyurethane; the nanocellulose has good hydrophobicity after modification and can be better dispersed in the hydrophobic polyurethane, so the waterproof property of the prepared composite polyurethane is further enhanced; the composite polyurethane is used as Adhesive layer 1, adhered to the substrate 2, and dried to prepare an ultra-thin composite polyurethane tape, making the tape have excellent waterproof properties.

[0174] For Comparative Examples 1 to 3, either the perfluoropolyether segments are not introduced (Comparative Example 1), or they are not blended and compounded with modified nanocellulose (Comparative Example 2), or neither of them is (Comparative Example 3). Therefore, their waterproof properties are poor and they cannot withstand a hydrostatic pressure of 500 mm for 300 s, and the water contact angles are also small.

[0175] The above results show and describe the basic principles, main features and advantages of the present application.

[0176] Those skilled in the art should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. An ultra-thin composite polyurethane tape with excellent waterproof property, characterized in that, The ultra-thin composite polyurethane tape includes a substrate (2) and an adhesive layer (1) adhered to one side of the substrate (2); the substrate (2) includes any one of non-woven fabric and elastic fabric; the adhesive layer (1) includes composite polyurethane; the composite polyurethane is formed by blending and compounding hydrophobic polyurethane and modified nano-cellulose; the hydrophobic polyurethane is formed by reacting polyether polyol with diisocyanate and further reacting with perfluoropolyether diol as a chain extender; The structural general formula of the diisocyanate is expressed as: ， The structural general formula of the polyether polyol is expressed as: ， R includes one or more of the following structures: 、 、 、 、 ； R' includes one or more of the following structures: 、 、 ； In the structural general formula of the polyether polyol, x is an integer in the range of 6 to 100; The structure of the perfluoropolyether diol is expressed as: ， Wherein, m is an integer in the range of 3 to 10; n is an integer in the range of 3 to 10; The thickness range of the ultra-thin composite polyurethane tape is 0.1 to 0.5 mm; in the composite polyurethane, the mass ratio of hydrophobic polyurethane to modified nano-cellulose is (90 to 95):(5 to 10); The modified nano-cellulose is nano-cellulose modified by a silane coupling agent; the silane coupling agent includes any one of octyltriethoxysilane, dodecyltriethoxysilane, and hexadecyltrimethoxysilane; the average particle size of the nano-cellulose is 50 to 200 nm.

2. An ultra-thin composite polyurethane tape with excellent waterproof performance according to claim 1, characterized in that, The preparation method of the modified nano-cellulose includes: First, add nano-cellulose into a flask and start stirring at room temperature; Then, drop the silane coupling agent into the nano-cellulose while stirring, and the dropping time is 1 to 2 minutes; Next, raise the temperature to 70 to 80 °C and continuously stir for 10 to 30 minutes, then discharge and cool to obtain the modified nano-cellulose, wherein the mass ratio of the silane coupling agent to the nano-cellulose is controlled at (1 to 5):

100.

3. A method for preparing an ultra-thin composite polyurethane tape with excellent waterproof performance according to any one of claims 1 to 2, characterized in that, It includes the following steps: First, dehydrate the polyether polyol, then add the polyether polyol dissolved in an organic solvent into a reaction kettle, raise the temperature to 60 to 80 °C under nitrogen protection, and then add diisocyanate and start stirring; Subsequently, add a catalyst into the reaction kettle, and then stir and react at this temperature for 2 to 4 hours to obtain a prepolymer; Then, add perfluoropolyether diol as a chain extender into the prepolymer, and continue to stir and react at 60 to 80 °C under nitrogen protection for 6 to 8 hours to prepare hydrophobic polyurethane; Then, add the modified nano-cellulose into the hydrophobic polyurethane, and carry out blending and compounding at 60 to 80 °C under nitrogen protection for 1 to 2 hours, and cool and discharge to obtain the composite polyurethane; Finally, use the composite polyurethane as the adhesive layer (1) and adhere it to the substrate (2), and dry it at 50 to 60 °C to obtain the ultra-thin composite polyurethane tape.

4. The preparation method of an ultra-thin composite polyurethane tape with excellent waterproof performance according to claim 3, characterized in that, The organic solvent includes one or two of ethyl acetate and dichloromethane; the catalyst includes one or more of organotin catalysts, organobismuth catalysts, and tertiary amine catalysts.

5. The preparation method of an ultra-thin composite polyurethane tape with excellent waterproof property according to claim 3, 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 to 40):(20 to 30):(20 to 30):(3 to 5):(10 to 20).

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