Waterborne polyurethane dispersion as well as preparation method and application thereof
Aqueous polyurethane dispersions were prepared by reacting isocyanate with hydrophobic polyols, which solved the problem that coatings in the prior art could not simultaneously achieve water and oxygen barrier properties, and achieved high-performance barrier properties and adhesion, making them suitable for food packaging and electronic components.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-10
AI Technical Summary
Coatings prepared from polyurethane dispersions in existing technologies are difficult to achieve in a way that simultaneously provides high-performance water and oxygen barrier properties.
Aqueous polyurethane dispersions were prepared by reacting isocyanate with hydrophobic polyols. The dispersions were formed through prepolymerization, chain extension, neutralization, and grafting reactions. Chain extenders and silane coupling agents were added to improve the barrier properties.
While reducing air permeability, it significantly improves oxygen barrier properties and enhances adhesion to non-polar materials, making it suitable for food packaging and electronic components.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of water and oxygen barrier coating, and particularly relates to a water-based polyurethane dispersion, a preparation method and application thereof. BACKGROUND
[0002] With the promotion of global environmental awareness and the promotion of circular economy policy, the recyclable technology of food packaging has become the key direction of industry development. Traditional food packaging mostly uses multi-layer composite materials (such as plastic-aluminum foil-paper base composite structure), which has excellent barrier property and preservation performance, but is difficult to separate and recycle efficiently, resulting in resource waste and environmental pollution. The design scheme of single material can help packaging recycling, which uses polypropylene (PP), polyethylene (PE) or polyethylene terephthalate (PET) and other single polymers, but its barrier property is poor, such as oxygen and moisture resistance, which may lead to shortening of food shelf life.
[0003] The polyurethane dispersion is used as a coating material, however, the coating prepared by the polyurethane dispersion in the prior art is difficult to have high-performance water and oxygen barrier properties. SUMMARY
[0004] The present application aims to overcome the problem that the coating prepared by the polyurethane dispersion in the prior art is difficult to have high-performance water and oxygen barrier properties, and further provides a water-based polyurethane dispersion, a preparation method and application thereof.
[0005] In a first aspect, the present application provides a water-based polyurethane dispersion, which comprises a polyurethane resin, and the polyurethane resin is a reaction product of isocyanate and polyol. The isocyanate comprises a first type of isocyanate, and the first type of isocyanate comprises xylene diisocyanate and pentamethylene diisocyanate. The polyol comprises a hydrophobic polyol.
[0006] In an optional embodiment, the isocyanate further comprises a second type of isocyanate, and the second type of isocyanate comprises at least one of hydrogenated xylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, tetramethyl m-xylylene diisocyanate, and hexamethylene diisocyanate. In an optional embodiment, the hydrophobic polyol comprises a polyolefin polyol.
[0007] In an optional embodiment, the hydrophobic polyol comprises at least one of polybutadiene diol and polyisoprene diol.
[0008] In an alternative embodiment, the hydrophobic polyol has a weight average molecular weight of 650-4000 g / mol.
[0009] In an alternative embodiment, the mass ratio of isocyanate to polyol is (40-45):(70-170). In an alternative embodiment, the mass ratio of the xylene diisocyanate and the pentamethylene diisocyanate is (10-20):(2-8). In an alternative embodiment, the mass ratio of the first type of isocyanate to the second type of isocyanate is (15-30):(15-30). In an alternative embodiment, the mass ratio of the first type of isocyanate to the hydrophobic polyol is (15-30):(70-180).
[0010] In a second aspect, the present application further provides a method for preparing the aqueous polyurethane dispersion, comprising the following steps: In an alternative embodiment, the mass ratio of isocyanate to polyol is (40-45):(70-170). The isocyanate includes a first type of isocyanate, and the first type of isocyanate includes xylene diisocyanate and pentamethylene diisocyanate. The polyol includes a hydrophobic polyol.
[0011] In an alternative embodiment, the mass ratio of isocyanate to polyol is (40-45):(70-170). The isocyanate further includes a second type of isocyanate, and the second type of isocyanate includes at least one of hydrogenated xylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, tetramethyl m-xylylene diisocyanate, and hexamethylene diisocyanate. In an alternative embodiment, the hydrophobic polyol includes a polyolefin polyol.
[0012] In an alternative embodiment, the hydrophobic polyol includes at least one of a polybutadiene diol and a polyisoprene diol.
[0013] In an alternative embodiment, the hydrophobic polyol has a weight average molecular weight of 650-4000 g / mol. In an alternative embodiment, the mass ratio of isocyanate to polyol is (40-45):(70-170). In one optional embodiment, the mass ratio of the phenylene diisocyanate to the pentamethyl diisocyanate is (10-20):(2-8). In one optional embodiment, the mass ratio of the first type of isocyanate to the second type of isocyanate is (15-30):(15-30). In one alternative embodiment, the mass ratio of the first type of isocyanate to the hydrophobic polyol is (15-30):(70-180).
[0014] In one alternative embodiment, the polyolefin polyol includes, but is not limited to, polybutadiene glycol and polyisoprene glycol.
[0015] In one optional embodiment, the prepolymerization reaction is carried out at a temperature of 45-80°C for 1-3 hours. In one alternative embodiment, a catalyst is also added to the prepolymerization reaction; In one optional embodiment, the catalyst is selected from organic bismuth catalysts; In one optional embodiment, the catalyst is added in an amount of 300-1000 ppm.
[0016] In one alternative embodiment, the organic bismuth catalyst is selected from, but not limited to, Bi 8210 or Bi 2010.
[0017] The catalyst addition amount is relative to the total amount of isocyanate and polyol.
[0018] In one optional embodiment, the chain extender in the chain extension reaction is selected from alcohol chain extenders.
[0019] In one optional embodiment, the chain extender in the chain extension reaction is selected from, but not limited to, 2,2-dimethylolpropionic acid (DMPA) and 2,2-dimethylolbutyric acid (DMBA).
[0020] In one optional embodiment, the chain extension reaction is carried out at a temperature of 40-70°C for 1-4 hours. In one optional embodiment, the mass ratio of the chain extender to the isocyanate is (1-5):(1-10). In an optional embodiment, the neutralizing agent for the neutralization reaction is selected from triethylamine (TEA), triethanolamine (TEOA), and dimethylethanolamine (DMEA).
[0021] In one optional embodiment, the neutralization reaction is carried out at a temperature of 30-60°C for a time of 0.3-1 h.
[0022] In an optional embodiment, the mass ratio of the neutralizing agent to the isocyanate is (4-5):(20-50).
[0023] In one alternative embodiment, the coupling agent in the grafting reaction is selected from silane coupling agents; In one alternative embodiment, the silane coupling agent contains at least one of an epoxy group, an amino group, a mercapto group, or a hydroxyl group. In one optional embodiment, the silane coupling agent is an amino-containing silane coupling agent; In one optional embodiment, the aminosilane-containing coupling agent comprises at least one of (3-aminopropyl)-trimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, (3-aminopropyl)-triethoxysilane, and γ-aminopropylmethyldiethoxysilane.
[0024] In one optional embodiment, the silane coupling agent is selected from KH-540, KH-550, KH-792, and KH-902.
[0025] In one optional embodiment, the grafting reaction is carried out at a temperature of 30-60°C for 0.5-2 hours. In one alternative embodiment, the mass ratio of the silane coupling agent to the isocyanate is (1-15):(3-40).
[0026] In one alternative embodiment, the mass ratio of water added during the process of dispersing water to obtain an emulsion is (100-200):(20-50).
[0027] In one optional embodiment, the chain extender added to the emulsion is selected from ethylenediamine, isophorone diamine, 1,4-cyclohexanedimethylamine, and m-phenylenediamine; In one alternative embodiment, the chain extender to isocyanate is added to the emulsion in a mass ratio of (1-3):(20-50).
[0028] Secondly, the present invention also provides an aqueous barrier coating, which is prepared using the aqueous polyurethane dispersion described above or the aqueous polyurethane dispersion prepared by the preparation method described above.
[0029] Thirdly, the present invention also provides the application of the above-described water-based barrier coating in packaging materials or electronic components.
[0030] The beneficial effects of this invention are: This invention provides an aqueous polyurethane dispersion comprising a polyurethane resin, which is a reaction product of an isocyanate and a polypolyol; the isocyanate includes a first type of isocyanate, comprising dimethyl phthalate (DMP) diisocyanate and pentamethylene diisocyanate; the polypolyol includes a hydrophobic polypolyol. The polyurethane resin raw materials contain DPP and pentamethylene diisocyanate, which, when combined with the hydrophobic polypolyol, can significantly improve oxygen barrier properties with minimal reduction in water permeability and enhance adhesion to non-polar materials.
[0031] Furthermore, the aqueous polyurethane dispersion 1) provided by this invention, when used in food packaging, does not produce free aromatic amines and is friendly to human health. Detailed Implementation
[0032] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0033] Polybutadiene glycol, purchased from Zibo Qilu Ethylene Chemical Co., Ltd.; Polyisoprene diol was purchased from Zibo Qilu Ethylene Chemical Co., Ltd. Polytetrahydrofuran diol was purchased from Shandong Lanxing Dongda. Polycarbonate diol was purchased from Wanhua Chemical. XDI - phenyldimethyl diisocyanate; PDI - pentamethylene diisocyanate; CHDI - cyclohexane-1,4-diisocyanate; IPDI - isophorone diisocyanate; H6XDI - hydrogenated phenyldimethyl diisocyanate; HMDI - dicyclohexylmethane-4,4'-diisocyanate.
[0034] Example 1 This embodiment provides a method for preparing an aqueous polyurethane dispersion, including the following steps: (1) Mix 12g of XDI, 6g of PDI, 24g of HMDI, 80g of polybutadiene glycol (molecular weight of 1000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI, HMDI and polybutadiene glycol) and heat to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0035] Example 2 This embodiment provides a method for preparing an aqueous polyurethane dispersion, including the following steps: (1) Mix 18g of XDI, 6g of PDI, 18g of CHDI, 76g of polyisoprene diol (molecular weight of 1000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI and CHDI) and heat to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.2g of KH-550 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0036] Example 3 This embodiment provides a method for preparing an aqueous polyurethane dispersion, including the following steps: (1) Mix 14g of XDI, 4g of PDI, 24g of IPDI, 80g of polybutadiene glycol (molecular weight of 1000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI, IPDI and polybutadiene glycol) and heat to 80°C for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-792 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0037] Example 4 This embodiment provides a method for preparing an aqueous polyurethane dispersion, including the following steps: (1) Mix 15g of XDI, 3g of PDI, 24g of H6XDI, 160g of polyisoprene diol (molecular weight of 2000g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI, H6XDI and polyisoprene diol) and heat to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Finally, 1.8g of KH-902 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0038] Example 5 This embodiment provides a method for preparing an aqueous polyurethane dispersion, including the following steps: (1) Mix 15g of XDI, 3g of PDI, 24g of HMDI, 160g of polyisoprene diol (molecular weight of 2000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI, HMDI and polyisoprene diol) and heat to 80°C for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0039] Comparative Example 1 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) Mix 32g of XDI, 80g of polybutadiene glycol (molecular weight of 1000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI and polybutadiene glycol added) and heat to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0040] Comparative Example 2 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) 18g of PDI, 24g of HMDI, 80g of polyisoprene glycol (molecular weight of 1000 g / mol) and 500ppm of Bi 8210 catalyst (relative to the total amount of PDI, HMDI and polyisoprene glycol added) were mixed and heated to 80℃ for 2h to obtain polyurethane prepolymer. (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h, followed by 4.2g of TEA and reacted at 35℃ for 1h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0041] Comparative Example 3 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) Mix 14g of XDI, 24g of HMDI, 80g of polytetrahydrofuran diol (molecular weight of 1000 g / mol) and 500ppm of Bi 8210 catalyst (relative to the total amount of XDI, HMDI and polytetrahydrofuran diol) and heat to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-792 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0042] Comparative Example 4 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) 42g of HMDI, 160g of polyisoprene glycol (molecular weight of 2000 g / mol) and 500ppm of Bi8210 catalyst (relative to the total amount of HMDI and polyisoprene glycol added) were mixed and heated to 80℃ for 2h to obtain polyurethane prepolymer. (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 1h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0043] Comparative Example 5 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) 40g of CHDI, 160g of polycarbonate diol (molecular weight of 2000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of CHDI and polycarbonate diol added) were mixed and heated to 80℃ for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0044] Comparative Example 6 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) Mix 18g of XDI, 24g of HMDI, 80g of polybutadiene glycol (molecular weight of 1000 g / mol) and 500ppm of Bi 8210 catalyst (relative to the total amount of XDI, HMDI and polybutadiene glycol) and heat to 80℃ for 2h to obtain polyurethane prepolymer. (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0045] Comparative Example 7 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) 18g of PDI, 24g of HMDI, 80g of polybutadiene glycol (molecular weight of 1000 g / mol) and 500ppm of Bi 8210 catalyst (relative to the total amount of PDI, HMDI and polybutadiene glycol added) were mixed and heated to 80℃ for 2h to obtain polyurethane prepolymer. (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0046] Comparative Example 8 This comparative example provides a method for preparing an aqueous polyurethane dispersion, comprising the following steps: (1) 12g of XDI, 6g of PDI, 24g of HMDI, 80g of polytetrahydrofuran diol (molecular weight of 1000 g / mol) and 500 ppm of Bi 8210 catalyst (relative to the total amount of XDI, PDI, HMDI and polytetrahydrofuran diol) were mixed and heated to 80°C for 2h to obtain polyurethane prepolymer; (2) 6.2g of DMPA was added to the polyurethane prepolymer and reacted at 65℃ for 4h. Then 4.2g of TEA was added and reacted at 35℃ for 0.5h. Then 1.5g of KH-540 was added and reacted at 35℃ for 0.5h to obtain the grafting product. (3) Add 200g of water to the grafting reaction product to disperse it and form a uniformly dispersed emulsion; then add 2.1g of ethylenediamine to the emulsion and continue the reaction for 30min to obtain an aqueous polyurethane dispersion.
[0047] Test example: The aqueous polyurethane dispersions prepared in the examples and comparative examples were coated onto films made on PP substrates, with a coating amount of 0.5 g / m³ (solid content). 2 The film thickness is 40 micrometers. It was dried at 120°C for 1 minute, then cured at 50°C for two days before testing. The main testing methods used in this invention are as follows: (1) Water vapor transmission rate: see GB / T 1037.
[0048] (2) Oxygen permeability: see GB / T 1038.
[0049] (3) Heat resistance: The ratio of the tensile strength of the sample to the strength before placement is measured after placing the sample in an oven at 150℃ for 1 hour.
[0050] (4) Water resistance: The ratio of the tensile strength of the sample to its strength before immersion after soaking for 24 hours.
[0051] (5) Adhesion: Cross-cut test. 5 is the worst and 0 is the best.
[0052] The experimental results are shown in Table 1 below: Table 1
[0053] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. An aqueous polyurethane dispersion, characterized in that, The waterborne polyurethane dispersion includes a polyurethane resin, which is a reaction product of isocyanate and polyol; The isocyanate includes a first type of isocyanate, which includes xylene diisocyanate and pentamethylene diisocyanate; The polyol includes a hydrophobic polyol.
2. The aqueous polyurethane dispersion according to claim 1, characterized in that, The isocyanate also includes a second type of isocyanate; the second type of isocyanate includes at least one of hydrogenated xylylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, tetramethyl m-xylylene diisocyanate, and hexamethylene diisocyanate; Preferably, the hydrophobic polyol includes a polyolefin polyol; Preferably, the hydrophobic polyol includes at least one of polybutadiene diol and polyisoprene diol; Preferably, the hydrophobic polyol has a weight average molecular weight of 650-4000 g / mol.
3. The aqueous polyurethane dispersion according to claim 1 or 2, characterized in that, The mass ratio of isocyanate to polyol is (40-45):(70-170); Preferably, the mass ratio of xylene diisocyanate to pentamethylene diisocyanate is (10-20):(2-8); Preferably, the mass ratio of the first type of isocyanate to the second type of isocyanate is (15-30):(15-30); Preferably, the mass ratio of the first type of isocyanate to the hydrophobic polyol is (15-30):(70-180).
4. A process for the preparation of an aqueous polyurethane dispersion, characterized in that, The method includes the following steps: Prepolymerization of isocyanate and polyol, followed by chain extension, neutralization, grafting, and then water dispersion to obtain an emulsion, and then adding a chain extender to the emulsion to obtain the waterborne polyurethane dispersion; The isocyanate includes a first type of isocyanate, which includes xylene diisocyanate and pentamethylene diisocyanate; The polyol includes a hydrophobic polyol.
5. The production method according to claim 4, characterized by, The mass ratio of isocyanate to polyol in the prepolymerization is (40-45):(70-170); The isocyanate also includes a second type of isocyanate; the second type of isocyanate includes at least one of hydrogenated xylylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, tetramethyl m-xylylene diisocyanate, and hexamethylene diisocyanate; Preferably, the hydrophobic polyol includes a polyolefin polyol; Preferably, the hydrophobic polyol includes at least one of polybutadiene diol and polyisoprene diol; Preferably, the hydrophobic polyol has a weight average molecular weight of 650-4000 g / mol. Preferably, the mass ratio of xylene diisocyanate to pentamethylene diisocyanate is (10-20):(2-8); Preferably, the mass ratio of the first type of isocyanate to the second type of isocyanate is (15-30):(15-30); Preferably, the mass ratio of the first type of isocyanate to the hydrophobic polyol is (15-30):(70-180).
6. The production method according to claim 4 or 5, characterized by, The temperature of the prepolymerization is 45-80℃; the time is 1-3h; Preferably, a catalyst is added in the prepolymerization; Preferably, the catalyst is selected from organic bismuth catalysts; Preferably, the catalyst is added in an amount of 300-1000 ppm.
7. The method of any one of claims 4-6, wherein, The chain extender in the chain extension reaction is selected from alcohol chain extenders; Preferably, the chain extender includes at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid; Preferably, the temperature of the chain extension reaction is 40-70℃, and the time is 1-4h; Preferably, the mass ratio of the chain extender to isocyanate is (1-5):(1-10).
8. The method of any one of claims 4-7, wherein, The coupling agent in the grafting reaction is selected from silane coupling agents; Preferably, the silane coupling agent contains at least one of epoxy, amino, mercapto or hydroxyl groups; Preferably, the silane coupling agent is an amino-containing silane coupling agent; Preferably, the amino-containing silane coupling agent includes at least one of (3-aminopropyl)-trimethoxysilane, N-(n-butyl)-3-aminopropyltrimethoxysilane, (3-aminopropyl)-triethoxysilane, γ-aminopropylmethyldiethoxysilane; Preferably, the temperature of the grafting reaction is 30-60℃; the time is 0.5-2h; Preferably, the mass ratio of the silane coupling agent to isocyanate is (1-15):(3-40).
9. An aqueous barrier coating, characterized in that, The water-based polyurethane dispersion is prepared by using the water-based polyurethane dispersion of any one of claims 1-3 or the preparation method of any one of claims 4-8.
10. Use of the water-based barrier coating of claim 9 in packaging materials or electronic components.
10. Use of the water-based barrier coating of claim 9 in packaging materials or electronic components.