Low-viscosity waterborne polyurethane adhesive and application thereof
By using a core-shell structure of polyoxypropylene-polyoxyethylene block copolymer and polybutylene adipate, along with a chain extender, in waterborne polyurethane adhesives, the problems of insufficient thermal shock and high-temperature aging performance of waterborne polyurethane adhesives are solved, thereby improving high-temperature stability and bonding strength.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-03-31
AI Technical Summary
Existing waterborne polyurethane adhesives have shortcomings in terms of thermal shock and high-temperature aging performance, making it difficult to meet the requirements of automotive interior parts for bonding strength and durability.
A specific combination of active molecules, including polyoxypropylene and polyoxyethylene block copolymers and polybutylene adipate, is used to enhance water solubility by forming a core-shell structure. Hexamethylenediamine and modified amines are used as chain extenders to control viscosity and improve bond strength and high-temperature stability.
The peel strength of the low-viscosity waterborne polyurethane adhesive exceeded 40 N/mm after aging at 105℃ for 500 hours, improving the ease of application and high-temperature aging performance while maintaining good adhesion.
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Figure CN121759145A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of waterborne polyurethane technology, and more specifically, to a low-viscosity waterborne polyurethane adhesive and its application. Background Technology
[0002] With the rapid development of my country's automotive industry, the market demand for automotive adhesives is increasing daily. The extensive use of leather and plastics in automotive structures has led to a continuous growth in the demand for automotive adhesives and sealants. Automotive polyurethane adhesives offer superior toughness, room temperature curing properties, and better adhesion to plastic parts compared to epoxy resin adhesives. They boast high bond strength, good impact and chemical resistance, a wide range of bonding materials, and better adaptability in automobiles and other moving parts. Therefore, polyurethane adhesives have been widely used in automotive manufacturing in countries such as the United States and Japan, becoming one of the main types of automotive adhesives. Waterborne polyurethane adhesives are particularly widely used, applying to the bonding of components such as car headliners, carpets, floor mats, dashboards, door panels, and seats. These applications often involve bonding the edges and corners of different materials, placing higher demands on the adhesive's viscosity, aging performance, and mechanical properties.
[0003] CN100480349 discloses a method for preparing a modified waterborne polyurethane adhesive. The method involves modifying an epoxy resin with a modifier to obtain a modified epoxy resin; reacting a polyisocyanate with a polyester or polyether polyol, then adding a chain extender to obtain a polyurethane prepolymer; modifying the polyurethane prepolymer with the modified epoxy resin to obtain a modified polyurethane prepolymer; finally, dispersing the modified polyurethane prepolymer with water using a high-speed disperser, adding a neutralizing agent and a crosslinking agent to obtain the modified waterborne polyurethane adhesive. This method offers advantages such as high film weight, high strength, and good chemical resistance, but its performance under thermal shock and high-temperature aging is not investigated. Summary of the Invention
[0004] The first aspect of the present invention provides a low-viscosity waterborne polyurethane adhesive, comprising component A and component B, wherein component A comprises an active molecule, a capping agent and a chain extender, and component B comprises a curing agent.
[0005] The curing agent is a commercially available polyurethane curing agent.
[0006] Preferably, the curing agent includes at least one of TSE-100 (Asahi Kasei), Desmodur N3300 (Covestro), and XP-2655 (Covestro).
[0007] Preferably, the capping agent includes HDI (hexamethylene diisocyanate).
[0008] The active molecules include a first active molecule, a second active molecule, a third active molecule, a fourth active molecule, and a fifth active molecule.
[0009] The first active molecule is prepared from raw materials including hydroxyl-terminated rubber, isocyanate, and dimer polyester polyol.
[0010] Preferably, the dimer acid polyester polyol has a functionality of 2-3 and a hydroxyl value of 350-400 mgKOH / g.
[0011] More preferably, the dimer acid polyester polyol has a functionality of 2, a hydroxyl value of 374 mgKOH / g, and the brand name is Oleon 1990.
[0012] Preferably, the molecular weight of the hydroxyl-terminated rubber is 2000-3000.
[0013] More preferably, the hydroxyl-terminated rubber has a molecular weight of 2000 and is graded Krasol LBH2000.
[0014] Preferably, the isocyanate comprises HDI.
[0015] Preferably, the weight ratio of the hydroxyl-terminated rubber, isocyanate, and dimer polyester polyol is 100:(15-20):(40-60).
[0016] More preferably, the weight ratio of the hydroxyl-terminated rubber, isocyanate, and dimer polyester polyol is 100:16.8:53.9.
[0017] The second active molecule includes a polyoxypropylene-polyoxyethylene block copolymer.
[0018] The polyoxypropylene-polyoxyethylene block copolymer has a molecular weight of 2000-5000 and a hydroxyl value of 10-50 mgKOH / g.
[0019] Preferably, the polyoxypropylene-polyoxyethylene block copolymer has a molecular weight of 2900, a hydroxyl value of 38.7 mgKOH / g, brand: BASF, grade: Pluronic-6400.
[0020] The third active molecule includes modified polyether polyol and HDI.
[0021] Preferably, the modified polyether polyol includes polytetrahydrofuran polyol.
[0022] Preferably, the polytetrahydrofuran polyol has a molecular weight of 1000-3000 and a hydroxyl value of 30-40 mgKOH / g.
[0023] Preferably, the modified polytetrahydrofuran polyol has a molecular weight of 1450, a hydroxyl value of 37 mgKOH / g, and the brand name is LYCRA 3MCPG 1450.
[0024] The fourth active molecule includes polybutylene adipate.
[0025] The molecular weight of the polybutylene adipate is 2000-5000.
[0026] Preferably, the molecular weight of the polybutylene adipate is 2000-3000.
[0027] More preferably, the polybutylene adipate has a molecular weight of 2000-3000, grade: PBA-2000, brand: Xuchuan.
[0028] The fifth active molecule includes dimethylolpropionic acid.
[0029] The weight ratio of the second active molecule to the fourth active molecule is 1:(2-5).
[0030] The applicant's research has found that the second active molecule includes a polyoxypropylene-polyoxyethylene block copolymer, and the fourth active molecule includes polybutylene adipate. The weight ratio of the second active molecule to the fourth active molecule is 1:(2-5), which can effectively control the viscosity between 4000-6000 cps, while improving the bonding strength and high-temperature aging resistance. In an aqueous environment, the hydrophilic and hydrophobic blocks of the polyoxypropylene-polyoxyethylene block copolymer associate with each other through intramolecular and intermolecular association. The hydrophilic segments extend outward toward the aqueous phase, while the hydrophobic segments aggregate inward to form a core-shell structure, which enhances water solubility and improves the dispersion performance between active molecules. At the same time, polybutylene adipate acts as a backbone structure during the crosslinking process, improving the bonding and high-temperature stability through intermolecular interactions.
[0031] Preferably, the weight ratio of the second active molecule to the fourth active molecule is 1:(4-5).
[0032] The weight ratio of the first active molecule to the second active molecule is 1:(0.8-1.2).
[0033] Preferably, the weight ratio of the first active molecule to the second active molecule is 1:(0.9-1.2).
[0034] The chain extender comprises hexamethylenediamine and modified amine, wherein the weight ratio of hexamethylenediamine to modified amine is 1:(10-20).
[0035] Preferably, the weight ratio of hexamethylenediamine to modified amine is 1:(12-18).
[0036] The modified amine is prepared from raw materials including a first compound, a second compound, melamine, triethylamine, and hexamethylenediamine. The raw material for preparing the first compound includes hydroxyl-terminated rubber, and the raw material for preparing the second compound includes polyethylene glycol.
[0037] Preferably, the hydroxyl-terminated rubber has a molecular weight of 2000 and a grade of Krasol_LBH2000.
[0038] Preferably, the molecular weight of the polyethylene glycol is 300-1000.
[0039] More preferably, the polyethylene glycol has a molecular weight of 300 and was purchased from Jinan Aoxing.
[0040] Acryloyl chloride is also included in the raw materials for the preparation of both the first and second compounds.
[0041] The method for preparing the modified amine includes the following steps: Step 1: Dehydrate the hydroxyl-terminated rubber under vacuum, then add acryloyl chloride to the ice-salt bath for reaction, and wash with water to remove the acryloyl chloride to obtain the first compound; Step 2: Dehydrate polyethylene glycol under vacuum, then add acryloyl chloride in an ice-salt bath to react, and wash with water to remove acryloyl chloride, thus obtaining the second compound; Step 3: Mix the first compound, the second compound and melamine, add triethylamine to carry out Michael addition reaction, add hexamethylenediamine to cap the reaction, remove triethylamine under vacuum, and dry to obtain the final product.
[0042] The molar ratio of the first compound, the second compound, and melamine is 1:(0.4-0.6):(0.4-0.6).
[0043] Preferably, the molar ratio of the first compound, the second compound, and melamine is 1:0.5:0.5.
[0044] The viscosity of component A is 4000-6000 cps.
[0045] The preparation method of component A is as follows: adding active molecules, controlling the amount of capping agent, adjusting the NCO value to 6-8, neutralizing with triethylamine, adding chain extender, removing acetone, and the resulting product is component A.
[0046] The polyurethane adhesive has a peel strength >40 N / mm after aging at 105°C for 500 hours.
[0047] A second aspect of the present invention provides an application of a low-viscosity waterborne polyurethane adhesive for bonding leather and plastic edges in automotive interiors.
[0048] Beneficial effects 1. The viscosity of component A is moderate, which effectively improves the convenience of application.
[0049] 2. The A component prepared in this application can be used with a variety of commercially available curing agents and has stable high-temperature aging performance and bonding performance.
[0050] 3. The chain extender includes hexamethylenediamine and modified amine, and the weight ratio of hexamethylenediamine to modified amine is 1:(10-20), which effectively solves the technical problem of water solubility and improves the associative performance. The peel force of the polyurethane adhesive is >40N / mm after aging at 105℃ for 500h.
[0051] 4. The second active molecule includes a polyoxypropylene-polyoxyethylene block copolymer, and the fourth active molecule includes polybutylene adipate. The weight ratio of the second active molecule to the fourth active molecule is 1:(2-5), which can effectively control the viscosity between 4000-6000 cps, while improving the bonding strength and high-temperature aging resistance.
[0052] 5. The weight ratio of the first active molecule to the second active molecule is 1:(0.9-1.2), which effectively improves the low-temperature performance of the adhesive. Attached Figure Description
[0053] Figure 1 The synthetic routes for the first active molecule in Examples 1-6 are shown.
[0054] Figure 2 The synthetic route for the third active molecule in Examples 1-6 is shown.
[0055] Figure 3 The synthetic routes for the first compound in the modified amines of Examples 1-6 are shown.
[0056] Figure 4 The synthetic routes for the second compound in the modified amines of Examples 1-6 are shown.
[0057] Figure 5 The following are the synthetic routes for the modified amines in Examples 1-6. Detailed Implementation
[0058] Examples 1-6 A low-viscosity waterborne polyurethane adhesive comprises component A and component B, wherein component A is an active molecule, a capping agent, and a chain extender, and component B is a curing agent.
[0059] The weight ratios of the active molecules in component A and the capping agent are shown in Table 1.
[0060] The capping agent is HDI (hexamethylene diisocyanate).
[0061] The first active molecule is prepared from hydroxyl-terminated rubber, isocyanate and dimer polyester polyol, wherein the weight ratio of hydroxyl-terminated rubber, isocyanate and dimer polyester polyol is 100:16.8:53.9.
[0062] The dimer acid polyester polyol has a functionality of 2, a hydroxyl value of 374 mgKOH / g, and is brand name Oleon 1990.
[0063] The hydroxyl-terminated rubber has a molecular weight of 2000 and is graded Krasol_LBH2000.
[0064] The isocyanate is HDI.
[0065] like Figure 1 As shown, the synthesis method of the first active molecule is as follows: the hydroxyl-terminated rubber is dehydrated under vacuum at 120°C, then cooled to 60°C and isocyanate is added. The reaction is carried out for 4 hours to obtain HDI-terminated modified rubber. Dimeric acid polyester polyol is then added after vacuum dehydration to obtain the final product.
[0066] The second active molecule is a polyoxypropylene-polyoxyethylene block copolymer.
[0067] The polyoxypropylene-polyoxyethylene block copolymer has a molecular weight of 2900, a hydroxyl value of 38.7 mgKOH / g, brand: BASF, grade: Pluronic-6400.
[0068] The third active molecule is a modified polyether polyol and HDI.
[0069] The modified polyether polyol is a polytetrahydrofuran polyol.
[0070] like Figure 2 As shown, the synthesis method of the third active molecule is as follows: the modified polyether polyol is dehydrated under vacuum, then HDI is added at 60°C, the reaction is carried out for 4 hours, and the R value is set to 0.55 to obtain the molecule.
[0071] The modified polytetrahydrofuran polyol has a molecular weight of 1450, a hydroxyl value of 37 mgKOH / g, and the brand name is LYCRA3MCPG 1450.
[0072] The fourth active molecule is polybutylene adipate.
[0073] The polybutylene adipate has a molecular weight of 2000-3000, grade: PBA-2000, brand: Xuchuan.
[0074] The fifth active molecule is dimethylolpropionic acid.
[0075] As shown in Table 2, the chain extender, by mass ratio, is hexamethylenediamine and modified amine. The modified amine is prepared from a first compound, a second compound, melamine, triethylamine, and hexamethylenediamine. The first compound is prepared from hydroxyl-terminated rubber and acryloyl chloride, and the second compound is prepared from polyethylene glycol and acryloyl chloride.
[0076] The hydroxyl-terminated rubber has a molecular weight of 2000 and is graded Krasol_LBH2000.
[0077] The polyethylene glycol has a molecular weight of 300 and was purchased from Jinan Aoxing.
[0078] The method for preparing the modified amine comprises the following steps: Step 1: As Figure 3 As shown, the hydroxyl-terminated rubber was dehydrated under vacuum, then acryloyl chloride was added to an ice-salt bath to react, and the acryloyl chloride was removed by washing with water to obtain the first compound. Step 2: As Figure 4 As shown, polyethylene glycol was dehydrated under vacuum, then acryloyl chloride was added to an ice-salt bath to react, and the acryloyl chloride was removed by washing with water to obtain the second compound. Step 3: As Figure 5 As shown, the first compound, the second compound and melamine were mixed, and triethylamine was added to carry out a Michael addition reaction (20°C, 3h). Hexamethylenediamine was added to cap the reaction (20°C, 2h), the triethylamine was removed under vacuum, and the mixture was dried to obtain the final product.
[0079] In step 1, the molar ratio of hydroxyl-terminated rubber to acryloyl chloride is 1:2.
[0080] In step 2, the molar ratio of polyethylene glycol to acryloyl chloride is 1:2.
[0081] The molar ratio of the first compound, the second compound, and melamine is 1:0.5:0.5.
[0082] In step 3, the amount of triethylamine used is 5 wt% of the amount of melamine used.
[0083] The preparation method of component A is as follows: adding active molecules, controlling the amount of capping agent (HDI), adjusting the NCO value, obtaining HDI-capped prepolymer, neutralizing with triethylamine, adding chain extender, removing acetone, and the resulting product is component A.
[0084] The NCO values in Examples 1-6 are 7.2, 7.2, 7.2, 7.0, 7.0 and 7.2, respectively.
[0085] The mass ratios of the HDI-terminated prepolymer, hexamethylenediamine, and modified amine are shown in Table 2.
[0086] The B component is shown in Table 3.
[0087] Table 1
[0088] Table 2
[0089] Table 3
[0090] Performance testing methods The components A and B prepared in Examples 1-6 were mixed in a ratio of 20:1, then placed in a spray bottle and sprayed at 0.1 MPa to a thickness of 10 micrometers onto the leather and seat back panel (substrates PP and ABS, respectively). Both components were then dried separately in an oven at 45°C for 30 minutes. Afterward, they were hot-pressed together on a machine at a pressure of 0.5 MPa and an activation temperature of 70°C. The mixture was then cooled to room temperature and allowed to stand at room temperature for 72 hours to complete curing. The resulting product underwent performance testing, and the test data are listed in Table 4 (where 50 N / mm is the material breaking value, i.e., the maximum strength that the leather used can withstand).
[0091] Viscosity test: The viscosity of the mixture was measured by mixing component A and component B at a mass ratio of 20:1 using a BROOKFIELF viscometer with a No. 27 rotor at 25°C. The unit is cps.
[0092] Peel strength test: The test conditions are a speed of 50 mm / min, 25 mm leather; the unit is N / mm; the test method refers to GB / T 2792-1998.
[0093] Thermal shock test reference: The sample (obtained according to the above sample preparation method) is placed in a thermal shock chamber and kept at -40℃ for 4 hours, then heated to 80℃ for 4 hours, then kept at 80℃ for 4 hours, then cooled to -40℃ for another 4 hours, and then kept at -40℃ for another 4 hours, which constitutes one loop. After the sample has been treated in the set loop, it is taken out and placed at room temperature (25℃) for one day before the peel strength is tested; the peel strength test method is as described above.
[0094] Performance test data Table 4
Claims
1. A low-viscosity waterborne polyurethane adhesive, characterized in that, The product comprises component A and component B. Component A includes an active molecule, a capping agent, and a chain extender. The active molecule includes a first active molecule, a second active molecule, a third active molecule, a fourth active molecule, and a fifth active molecule. The first active molecule is prepared from raw materials including hydroxyl-terminated rubber, isocyanate, and dimer polyester polyol. The second active molecule includes a polyoxypropylene-polyoxyethylene block copolymer. The third active molecule includes a modified polyether polyol. The fourth active molecule includes polybutylene adipate. The fifth active molecule includes dimethylolpropionic acid. The weight ratio of the second active molecule to the fourth active molecule is 1:(2-5). Component B includes a curing agent.
2. The low-viscosity waterborne polyurethane adhesive according to claim 1, characterized in that, The weight ratio of the first active molecule to the second active molecule is 1:(0.8-1.2).
3. The low-viscosity waterborne polyurethane adhesive according to claim 2, characterized in that, The chain extender comprises hexamethylenediamine and modified amine, wherein the weight ratio of hexamethylenediamine to modified amine is 1:(10-20).
4. The low-viscosity waterborne polyurethane adhesive according to claim 3, characterized in that, The modified amine is prepared from raw materials including a first compound, a second compound, melamine, triethylamine, and hexamethylenediamine. The raw material for preparing the first compound includes hydroxyl-terminated rubber, and the raw material for preparing the second compound includes polyethylene glycol.
5. The low-viscosity waterborne polyurethane adhesive according to claim 4, characterized in that, Acryloyl chloride is also included in the raw materials for the preparation of both the first and second compounds.
6. The low-viscosity waterborne polyurethane adhesive according to claim 5, characterized in that, The method for preparing the modified amine includes the following steps: Step 1: Dehydrate the hydroxyl-terminated rubber under vacuum, then add acryloyl chloride to the ice-salt bath for reaction, and wash with water to remove the acryloyl chloride to obtain the first compound; Step 2: Dehydrate polyethylene glycol under vacuum, then add acryloyl chloride in an ice-salt bath to react, and wash with water to remove acryloyl chloride, thus obtaining the second compound; Step 3: Mix the first compound, the second compound and melamine, add triethylamine to carry out Michael addition reaction, add hexamethylenediamine to cap the reaction, remove triethylamine under vacuum, and dry to obtain the final product.
7. The low-viscosity waterborne polyurethane adhesive according to claim 6, characterized in that, The molar ratio of the first compound, the second compound, and melamine is 1:(0.4-0.6):(0.4-0.6).
8. The low-viscosity waterborne polyurethane adhesive according to claim 1 or 7, characterized in that, The viscosity of component A is 4000-6000 cps.
9. The low-viscosity waterborne polyurethane adhesive according to claim 1, characterized in that, The polyurethane adhesive has a peel strength >40 N / mm after aging at 105°C for 500 hours.
10. An application of the low-viscosity waterborne polyurethane adhesive according to any one of claims 1-9, characterized in that, It is used for bonding leather and plastic edges in automotive interiors.