Epoxy-polyurethane hybrid two-component structural adhesive and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to an epoxy-polyurethane hybrid two-component structural adhesive and a preparation method thereof. The bi-component structural adhesive comprises a component A and a component B. The component A comprises the following raw materials in parts by weight: 20-40 parts of isocyanate-terminated modified polyurethane resin, 50-60 parts of epoxy resin, 0.5-1 part of a coupling agent, 10-20 parts of inorganic powder filler and 0.01-0.05 part of toner A; the component B is prepared from the following raw materials in parts by weight: 65 to 75 parts of hydroxyl-terminated modified polyurethane resin, 20 to 25 parts of amine curing agent, 0.5 to 1 part of coupling agent, 0.01 to 0.05 part of toner B and 0.05 to 0.1 part of catalyst. Compared with a traditional two-component epoxy structural adhesive, the epoxy structural adhesive has more excellent potting filling performance, more excellent bonding strength, better flexibility and more balanced body strength, and is suitable for the fields of new energy battery potting and high-end industrial potting adhesives.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesives, in particular to an epoxy-polyurethane hybrid two-component structural adhesive and a preparation method thereof. BACKGROUND

[0002] In recent years, new energy vehicles have made rapid progress. As one of the key materials in the manufacturing process of new energy vehicles, adhesives for new energy vehicles have also been continuously updated and iterated, continuously developing towards better performance and lower cost. It is evolving from single function to multi-dimensional coordination of "structure-thermal management-protection". This development trend is mainly driven by the popularization of CTP battery technology, the tightening of environmental regulations, and the demand for lightweight. It is expected that in the next five years, high-thermal-conductivity elastomers, bio-based adhesives, and intelligent gluing equipment will become the focus of technological breakthroughs in this field, driving the entire industry towards high performance, low cost, and green development.

[0003] In the field of new energy vehicles, traditional two-component epoxy structural adhesives have a certain range of applications, mainly used for vehicle body structure bonding, part sealing, and a small part of battery encapsulation. This type of adhesive has some notable advantages, such as high strength, wide temperature range adaptability, and good chemical stability. These characteristics make it play an important role in the manufacturing of new energy vehicles.

[0004] However, traditional two-component epoxy structural adhesives also have some obvious disadvantages. They have poor impact resistance and are prone to damage when subjected to impact, which is a significant risk for new energy vehicle components that need to withstand some impact. They also require high surface treatment of the substrate, which increases the difficulty and cost of construction in actual applications. The high process requirements make it face many challenges in large-scale production and application. These shortcomings limit the widespread application of traditional two-component epoxy structural adhesives in new energy vehicles and other related fields.

[0005] Therefore, in order to make two-component epoxy structural adhesives more widely applicable in new energy vehicles and other related fields, it is urgent to optimize and improve the formula of traditional two-component epoxy structural adhesives to overcome the shortcomings of existing technology and develop a two-component epoxy structural adhesive with better performance and stronger applicability. SUMMARY

[0006] To solve the above technical problems in the prior art, the present application provides an epoxy-polyurethane hybrid two-component structural adhesive and a preparation method thereof.

[0007] The technical solution of the present application to solve the above technical problems is as follows: The first aspect of the present invention is to provide an epoxy-polyurethane hybrid two-component structural adhesive, comprising component A and component B. Component A, by weight, comprises the following raw materials: 20-40 parts of isocyanate-terminated modified polyurethane resin, 50-60 parts of epoxy resin, 0.5-1 part of coupling agent, 10-20 parts of inorganic powder filler, and 0.01-0.05 parts of colorant A; component B comprises the following raw materials: 65-75 parts of hydroxyl-terminated modified polyurethane resin, 20-25 parts of amine curing agent, 0.5-1 part of coupling agent, 0.01-0.05 parts of colorant B, and 0.05-0.1 parts of catalyst.

[0008] Based on the above technical solution, the present invention can also be improved as follows: Furthermore, the isocyanate-terminated modified polyurethane resin is obtained by reacting isocyanate with polypropylene glycol, with a molar ratio of NCO groups to HO groups of (1~2):1.

[0009] Furthermore, the isocyanate-terminated modified polyurethane resin is prepared by the following method: Polypropylene glycol is first vacuum dehydrated in a high-speed planetary mixer at 120-130℃ until the water content is <0.02%; when the temperature is lowered to 80-100℃, a catalyst is added dropwise and stirred for 0.5h; excess isocyanate is added, and the temperature is controlled at 80-100℃ and stirred for 0.5h. Infrared spectroscopy is used to determine whether the hydroxyl groups have reacted completely. If the reaction is not complete, stirring is continued for 0.5h. This cycle is repeated until the hydroxyl groups have reacted completely; a dehydrating agent is added, and after stirring for 0.5h, the isocyanate-terminated modified polyurethane resin is obtained.

[0010] Furthermore, the hydroxyl-terminated modified polyurethane resin is obtained by reacting polypropylene glycol with isocyanate, and the molar ratio of HO groups to NCO groups is (1~2):1.

[0011] Furthermore, the hydroxyl-terminated modified polyurethane resin is prepared by the following method: First, excess polypropylene glycol is vacuum dehydrated in a high-speed planetary mixer at 120-130℃ until the water content is <0.02%; when the temperature is lowered to 80-100℃, a catalyst is added dropwise and stirred for half an hour; a small amount of isocyanate is added, and the temperature is controlled at 80-100℃ and stirred for 0.5h. Infrared spectroscopy is used to determine whether the isocyanate groups have reacted completely. If the reaction is not complete, stirring is continued for 0.5h. This cycle is repeated until the isocyanate groups have reacted completely; a dehydrating agent is added, and after stirring for 0.5h, the hydroxyl-terminated modified polyurethane resin is obtained.

[0012] Further, the isocyanate comprises one or more combinations of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), terephthalic diisocyanate (PPDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), phenylenediamine diisocyanate (XDI), tetramethyl isophthalimide diisocyanate (TMXDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), and methylcyclohexane diisocyanate (HTDI). Preferably, isophorone diisocyanate (IPDI) is preferred.

[0013] Furthermore, the polypropylene glycol comprises one or more of PPG400, PPG800, PPG1000, PPG1500, PPG2000, PPG3000, PPG4000, and PPG8000. PPG4000 and PPG8000 are preferred.

[0014] Furthermore, the catalyst comprises trivinyldiamine (TEDA), dimethylcyclohexylamine (DMCHA), N-methylmorpholine (NMM), dibutyltin dilaurate (T-9), and stannous octoate (T-12). Bismuth neodecanoate and zinc octanoate are one or more of the following: the epoxy resin comprises one or more of the following: bisphenol F epoxy resin, bisphenol A epoxy resin, alicyclic epoxy resin, aminophenol trifunctional epoxy resin, and polyurethane modified epoxy resin, preferably bisphenol A epoxy resin, and the resin used is E-51 epoxy resin, commercially known as Npel-128 from Nan Ya Plastics, Taiwan; the amine curing agent comprises one or more of the following: aliphatic polyamine, alicyclic polyamine, aromatic polyamine, polyamide polyamine, tertiary amines, imidazoles, and boronamine complexes, preferably alicyclic amines, commercially known as D230 from Huntsman; the coupling agent comprises γ-aminopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane. The catalyst comprises one or more of the following: alkylene, γ-mercaptopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane, preferably γ-glycidoxypropyltrimethoxysilane, commercially known as KH560 from Shandong Silicon Science & Technology Co., Ltd.; the inorganic powder filler comprises one or more of the following: silica powder, nano-calcium carbonate, heavy calcium carbonate, calcium oxide, talc, kaolin, and diatomaceous earth, preferably nano-calcium carbonate, commercially known as CCS-18 from Guangxi Huana New Materials Co., Ltd.; the catalyst comprises one or more of the following: trivinyldiamine (TEDA), dimethylcyclohexylamine (DMCHA), N-methylmorpholine (NMM), dibutyltin dilaurate (T-9), stannous octoate (T-12), bismuth neodecanoate, and zinc octoate, preferably dibutyltin dilaurate (T-9).

[0015] Furthermore, the mass ratio of component A to component B is 2:1.

[0016] Another aspect of the present invention is to provide a method for preparing the epoxy-polyurethane hybrid two-component structural adhesive provided in the first aspect of the present invention, comprising the following steps: Preparation of Component A: Epoxy resin, isocyanate-terminated modified polyurethane resin, coupling agent, and color powder A are added to a high-speed planetary mixer and stirred under vacuum for 1 hour. Then, inorganic powder filler is added, and vacuum stirring is continued for another 1 hour to obtain Component A. During the preparation process, the vacuum degree is maintained at no less than -0.08 MPa. Preparation of component B: Add hydroxyl-terminated modified polyurethane resin, amine curing agent, coupling agent, color powder B, and catalyst to a high-speed planetary mixer and stir under vacuum for 1-2 hours to obtain component B; during the preparation process, maintain a vacuum degree of not less than -0.08 MPa.

[0017] Compared with the prior art, the present invention has the following technical effects: By introducing self-synthesized isocyanate-terminated modified polyurethane resin and hydroxyl-terminated polyether-terminated modified polyurethane resin into a two-component epoxy structural adhesive formulation, impact strength, elongation at break, and adhesion strength to difficult-to-bond substrates (such as PP and PET) can be effectively improved. Detailed Implementation

[0018] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0019] Synthesis example 1 Synthetic isocyanate-terminated modified polyurethane resin NO-4131: 500g of PPG4000 was vacuum-stirred and dehydrated in a high-speed planetary mixer at 125℃ until the moisture content was <0.02%. The material temperature was then lowered to 80℃, and 0.05g of catalyst Kat 21 was added and stirred for half an hour. 36.96g of isocyanate was added (controlling the millimolecular ratio of NCO group content to HO group content to be 1.33:1). The mixture was stirred at 90℃ for 0.5h, and infrared spectroscopy was used to determine whether the hydroxyl groups had reacted completely. If not, stirring was continued for another 0.5h, and this cycle was repeated until the hydroxyl groups had reacted completely. Finally, p-toluenesulfonyl isocyanate (PTSI) was added as a dehydrating agent, and after stirring for 0.5h, the isocyanate-terminated modified polyurethane resin was obtained, named NO-4131.

[0020] Synthesis example 2 Synthetic isocyanate-terminated modified polyurethane resin NO-8151: 500g of PPG8000 was vacuum-stirred and dehydrated in a high-speed planetary mixer at 125℃ until the moisture content was <0.02%. The material temperature was then lowered to 80℃, and 0.05g of catalyst Kat 21 was added and stirred for half an hour. 20.78g of isocyanate was added (controlling the millimolecular ratio of NCO group content to hydroxyl content to be 1.52:1). The mixture was stirred at 90℃ for 0.5h, and infrared spectroscopy was used to determine whether the hydroxyl groups had reacted completely. If not, stirring was continued for another 0.5h, and this cycle was repeated until the hydroxyl groups had reacted completely. Finally, p-toluenesulfonyl isocyanate (PTSI) was added as a dehydrating agent, and after stirring for 0.5h, the isocyanate-terminated modified polyurethane resin was obtained, named NO-8151.

[0021] Synthesis example 3 Synthetic hydroxyl-terminated modified polyurethane resin HO-4671: 500g of PPG4000 was vacuum-stirred and dehydrated in a high-speed planetary mixer at 125℃ until the moisture content was <0.02%. The material temperature was then lowered to 80℃, and 0.05g of catalyst Kat 21 was added and stirred for half an hour. 18.62g of isocyanate was added (controlling the millimolecular ratio of HO group content to NCO content to be 1:0.67). The mixture was stirred at 90℃ for 0.5h, and infrared spectroscopy was used to determine whether the hydroxyl groups had reacted completely. If not, stirring was continued for another 0.5h, and this cycle was repeated until the hydroxyl groups had reacted completely. Finally, p-toluenesulfonyl isocyanate (PTSI), a dehydrating agent, was added, and the mixture was stirred for 0.5h to obtain the hydroxyl-terminated modified polyurethane resin, named HO-4671.

[0022] Synthesis example 4 Synthetic hydroxyl-terminated modified polyurethane resin HO-8481: 500g of PPG8000 was vacuum-stirred and dehydrated in a high-speed planetary mixer at 125℃ until the moisture content was <0.02%. The material temperature was then lowered to 80℃, and 0.05g of catalyst Kat 21 was added and stirred for half an hour. 6.56g of isocyanate was added (controlling the millimolecular ratio of HO group content to NCO content to be 1:0.48). The mixture was stirred at 90℃ for 0.5h, and infrared spectroscopy was used to determine whether the hydroxyl groups had reacted completely. If not, stirring was continued for another 0.5h, and this cycle was repeated until the hydroxyl groups had reacted completely. Finally, p-toluenesulfonyl isocyanate (PTSI), a dehydrating agent, was added, and the mixture was stirred for 0.5h to obtain the hydroxyl-terminated modified polyurethane resin, named HO-8481.

[0023] Example 1 The preparation of epoxy-polyurethane hybrid two-component structural adhesive includes the following steps: Preparation of Component A: Epoxy resin Npel-128, isocyanate-terminated modified polyurethane resin NO-4131, coupling agent KH560, and yellow powder were added to a high-speed planetary mixer and stirred under vacuum for 1 hour. Then, nano-calcium carbonate CCS-18 was added, and the mixture was stirred under vacuum for another 1 hour to obtain Component A. During the preparation process, the vacuum level was maintained at no less than -0.08 MPa. Preparation of component B: Add hydroxyl-terminated modified polyurethane resin HO-4671, alicyclic amine D230, coupling agent KH560, blue powder, and dibutyltin dilaurate (T-9) to a high-speed planetary mixer and stir under vacuum for 1 hour to obtain component B; during the preparation process, maintain a vacuum degree of not less than -0.08 MPa.

[0024] The mass fractions of each component added are shown in Table 1.

[0025] Example 2 The preparation method is the same as in Example 1, and the mass fractions of each component added are shown in Table 1.

[0026] Example 3 The preparation method is the same as in Example 1, and the mass fractions of each component added are shown in Table 1.

[0027] Example 4 The preparation method is the same as in Example 1, wherein the isocyanate-terminated modified polyurethane resin is NO-8151 and the hydroxyl-terminated modified polyurethane resin is HO-8481, and the mass fractions of each component added are shown in Table 1.

[0028] Example 5 The preparation method is the same as in Example 4, and the mass fractions of each component added are shown in Table 1.

[0029] Example 6 The preparation method is the same as in Example 4, and the mass fractions of each component added are shown in Table 1.

[0030] Comparative Example 1 The preparation method is the same as in Example 1, but without the addition of isocyanate-terminated modified polyurethane resin and hydroxyl-terminated modified polyurethane resin. The mass fractions of the remaining components are shown in Table 1.

[0031] Comparative Example 2 The preparation method is the same as in Example 1, but without the addition of isocyanate-terminated modified polyurethane resin. The mass fractions of the remaining components are shown in Table 1.

[0032] Comparative Example 3 The preparation method is the same as in Example 1, but without the addition of isocyanate-terminated modified polyurethane resin. The hydroxyl-terminated modified polyurethane resin used is HO-8481. The mass fractions of each component added are shown in Table 1.

[0033] Table 1. Preparation formulations for each example and comparative example.

[0034] The structural adhesives of Examples 1-6 and Comparative Examples 1-3 were subjected to the following performance tests: (1) Viscosity of A / B mixture; (2) Shear bond strength: PP / PP and PET / PET; (3) Impact resistance of the cantilever beam notch; (4) Elongation at break.

[0035] The test results are shown in Table 2.

[0036] Table 2 Comparison of typical data from Examples 1-6 and Comparative Examples 1-3

[0037] According to the performance test results in Table 2, compared with Comparative Examples 1-3, the epoxy-polyurethane hybrid two-component structural adhesives prepared in each embodiment of the present invention have excellent performance, especially the formulations of Example 3 and Example 6 have the best overall performance.

[0038] This invention introduces isocyanate-terminated polyurethane resin and hydroxyl-terminated polyurethane resin through self-synthesis, respectively, into components A and B of a traditional two-component epoxy adhesive. The self-synthesized modified resin is then combined with the epoxy resin to form an epoxy-polyurethane hybrid two-component structural adhesive. This hybrid two-component structural adhesive exhibits superior impact toughness, potting and filling performance, bond strength, flexibility, and more balanced bulk strength compared to traditional epoxy two-component structural adhesives. It is suitable for adhesive applications such as new energy battery potting and high-end industrial potting, and demonstrates higher bond strength to difficult-to-bond substrates.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An epoxy-polyurethane hybrid two-component structural adhesive, characterized in that, The product comprises component A and component B. By weight, component A comprises the following raw materials: 20-40 parts of isocyanate-terminated modified polyurethane resin, 50-60 parts of epoxy resin, 0.5-1 part of coupling agent, 10-20 parts of inorganic powder filler, and 0.01-0.05 parts of color powder A; component B comprises the following raw materials: 65-75 parts of hydroxyl-terminated modified polyurethane resin, 20-25 parts of amine curing agent, 0.5-1 part of coupling agent, 0.01-0.05 parts of color powder B, and 0.05-0.1 parts of catalyst.

2. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 1, characterized in that, The isocyanate-terminated modified polyurethane resin is obtained by reacting isocyanate with polypropylene glycol, with a molar ratio of NCO groups to HO groups of (1~2):

1.

3. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 2, characterized in that, The isocyanate-terminated modified polyurethane resin was prepared by the following method: Polypropylene glycol was first vacuum dehydrated in a high-speed planetary mixer at 120-130℃ until the water content was <0.02%; when the temperature was lowered to 80-100℃, a catalyst was added dropwise and stirred for 0.5h; excess isocyanate was added, and the temperature was controlled at 80-100℃ and stirred for 0.5h. Infrared spectroscopy was used to determine whether the hydroxyl groups had reacted completely. If the reaction was not complete, stirring was continued for 0.5h. This cycle was repeated until the hydroxyl groups reacted completely; a dehydrating agent was added, and after stirring for 0.5h, the isocyanate-terminated modified polyurethane resin was obtained.

4. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 1, characterized in that, The hydroxyl-terminated modified polyurethane resin is obtained by reacting polypropylene glycol with isocyanate, with a molar ratio of HO groups to NCO groups of (1~2):

1.

5. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 4, characterized in that, The hydroxyl-terminated modified polyurethane resin was prepared by the following method: First, excess polypropylene glycol was vacuum dehydrated in a high-speed planetary stirred tank at 120-130℃ until the water content was <0.02%; when the temperature was lowered to 80-100℃, a catalyst was added dropwise and stirred for half an hour; a small amount of isocyanate was added, and the temperature was controlled at 80-100℃ and stirred for 0.5h. Infrared spectroscopy was used to determine whether the isocyanate groups had reacted completely. If the reaction was not complete, stirring was continued for 0.5h. This cycle was repeated until the isocyanate groups had reacted completely; a dehydrating agent was added, and after stirring for 0.5h, the hydroxyl-terminated modified polyurethane resin was obtained.

6. The epoxy-polyurethane hybrid two-component structural adhesive according to any one of claims 2 to 5, characterized in that, The isocyanate comprises one or more combinations of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), terephthalic diisocyanate (PPDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), phenylmethylene diisocyanate (XDI), tetramethyl isophthalimethylene diisocyanate (TMXDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), and methylcyclohexane diisocyanate (HTDI).

7. The epoxy-polyurethane hybrid two-component structural adhesive according to any one of claims 2 to 5, characterized in that, The polypropylene glycol comprises one or more of PPG400, PPG800, PPG1000, PPG1500, PPG2000, PPG3000, PPG4000, and PPG8000.

8. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 1, characterized in that, The catalyst comprises one or more of the following: trivinyldiamine (TEDA), dimethylcyclohexylamine (DMCHA), N-methylmorpholine (NMM), dibutyltin dilaurate (T-9), stannous octoate (T-12), bismuth neodecanoate, and zinc octoate; the epoxy resin comprises one or more of the following: bisphenol F epoxy resin, bisphenol A epoxy resin, alicyclic epoxy resin, aminophenol trifunctional epoxy resin, and polyurethane modified epoxy resin; the amine curing agent comprises one or more of the following: aliphatic polyamine, alicyclic polyamine, aromatic polyamine, polyamide polyamine, tertiary amines, imidazoles, and boronamine complexes; the coupling agent comprises γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, ... The inorganic powder filler comprises one or more of the following: γ-mercaptopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane; the inorganic powder filler comprises one or more of the following: silica powder, nano-calcium carbonate, heavy calcium carbonate, calcium oxide, talc, kaolin, and diatomaceous earth; the catalyst comprises one or more of the following: trivinyldiamine (TEDA), dimethylcyclohexylamine (DMCHA), N-methylmorpholine (NMM), dibutyltin dilaurate (T-9), stannous octoate (T-12), bismuth neodecanoate, and zinc octoate.

9. The epoxy-polyurethane hybrid two-component structural adhesive according to claim 1, characterized in that, The mass ratio of component A to component B is 2:

1.

10. A method for preparing an epoxy-polyurethane hybrid two-component structural adhesive according to any one of claims 1 to 9, characterized in that, Includes the following steps: Preparation of Component A: Epoxy resin, isocyanate-terminated modified polyurethane resin, coupling agent, and color powder A are added to a high-speed planetary mixer and stirred under vacuum for 1 hour. Then, inorganic powder filler is added, and vacuum stirring is continued for another 1 hour to obtain Component A. During the preparation process, the vacuum degree is maintained at no less than -0.08 MPa. Preparation of component B: Add hydroxyl-terminated modified polyurethane resin, amine curing agent, coupling agent, color powder B, and catalyst to a high-speed planetary mixer and stir under vacuum for 1-2 hours to obtain component B; during the preparation process, maintain a vacuum degree of not less than -0.08 MPa.

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