High-toughness two-component epoxy adhesive and preparation method thereof

Through flexible segment modification technology, a dense loose structure is formed in epoxy adhesives, which solves the problem of insufficient toughness and heat resistance of traditional epoxy adhesives, and achieves high toughness and excellent tensile strength and hardness, which is suitable for a wide range of Industrial application and solvent-free addition, meeting environmental protection requirements.

CN119193072APending Publication Date: 2024-12-27SHENZHEN UNION TENDA TECH CO LTD
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Patent Information

Application Number
CN202411568918.6
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2024-11-05
Publication Date
2024-12-27

AI Technical Summary

Technical Problem

Traditional epoxy adhesives reduce toughness and flexibility when improving strength and heat resistance, resulting in a decrease in elongation of break and impact strength, limiting their application in high-end fields.

Method used

Flexible segment modification technology is used to form a dense but loose two-phase structure, embedded in the cross-linking network of epoxy to improve toughness without affecting heat resistance and strength, and control cross-linking by adjusting the content of isocyanate and polyether polyols. Spend.

Benefits of technology

It significantly improves the toughness and tensile strength of the adhesive, improves the elongation of break, and is suitable for a wider range of industrial application scenarios, and is solvent-free and meets environmental protection requirements.

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Abstract

The invention discloses a high-toughness double-component epoxy adhesive and a preparation method thereof, the epoxy adhesive is composed of a component A and a component B, and the volume ratio of the component A to the component B is 2: 1; the component A is prepared from the following raw materials in parts by weight: 12-30 parts of epoxy resin E51, 3-15 parts of tetrafunctional epoxy resin AG80, 5-18 parts of a flexible chain segment product A1 and 50-70 parts of heavy calcium carbonate filler; wherein the flexible chain segment product A1 is prepared from the following raw materials in parts by weight: 30 to 60 parts of polyether polyol, 35 to 55 parts of isocyanate, 0.2 to 1.0 part of a catalyst and 165 to 250 parts of hydroxyl-terminated epoxidized polybutadiene resin. Flexible chain segments are introduced into the epoxy adhesive for modification, so that the toughness of the adhesive is improved, the curing agent can be embedded into an epoxy cross-linked network, a compact and loose two-phase structure is formed, and the influence on the heat resistance and strength of epoxy is small while the toughness is improved.
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Description

Technical Field

[0001] The invention relates to the technical field of epoxy adhesives, and in particular to a high-toughness two-component epoxy adhesive and a preparation method thereof. Background Art

[0002] Epoxy adhesives are widely used in industry due to their excellent adhesion, heat resistance, chemical resistance, good mechanical properties, outstanding dielectric properties and low curing shrinkage. Traditional epoxy adhesives form a multi-crosslinked network structure through a ring-opening reaction between epoxy resin and curing agent, which can improve the strength and heat resistance of the adhesive. However, this increase in strength is often accompanied by increased brittleness, decreased flexibility and excessive crosslinking, resulting in reduced elongation at break and impact strength, limiting the application of epoxy adhesives in high-end fields.

[0003] In order to solve the above problems, the current toughening modification methods mainly include adding rubber, thermoplastic elastomers, nanomaterials, etc. to epoxy adhesives. Although these methods can improve the toughness of adhesives, they may also weaken the performance of adhesives. For example, rubber can significantly improve the toughness after curing, but it will greatly reduce the strength; thermoplastic elastomers have little effect on strength, but require high molecular weight to have high toughness, which will lead to increased viscosity and bring difficulties to production and processing; nanomaterials have a large specific surface area, and some active groups can also react with epoxy, with good compatibility, but nanomaterials are prone to agglomeration problems.

[0004] In the prior art, Chinese patent CN102925091B discloses a high-strength and high-toughness epoxy resin adhesive and a preparation method thereof, in which a high-strength epoxy resin adhesive is prepared by using polyetheramine and IPDA curing agent for toughening, and its tensile strength is as high as 64Mpa, but the bulk elongation is only 2.6%, and the toughness is relatively low; Chinese patent CN 114672271A discloses an epoxy structural adhesive film for aviation organic glass bonding and a preparation method thereof, which uses polyurethane modified epoxy resin and vinyl ester resin to enhance the wettability with organic glass and polyester steel, and then adds liquid rubber and core-shell particles to toughen the epoxy resin, which is applied to the epoxy structural adhesive film. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a high-toughness two-component epoxy adhesive and a preparation method thereof. Firstly, solvent-free addition is achieved from the perspective of environmental protection, and flexible chain segment modification is adopted. The curing agent will be embedded in the cross-linked network of the epoxy to form a dense but loose two-phase structure, which has little effect on the heat resistance or strength of the epoxy, and at the same time can improve its toughness.

[0006] In order to achieve the above object, the present invention provides a high-toughness two-component epoxy adhesive, the epoxy adhesive is composed of two components A and B, and the volume ratio of component A to component B is 2:1;

[0007] The A component is prepared from the following raw materials in parts by weight:

[0008] 12-30 parts by weight of epoxy resin E51, 3-15 parts by weight of tetrafunctional epoxy resin AG80, 5-18 parts by weight of flexible segment product A1, and 50-70 parts by weight of heavy calcium carbonate filler; wherein the raw materials for preparing the flexible segment product A1 are: 30-60 parts by weight of polyether polyol, 35-55 parts by weight of isocyanate, 0.2-1 parts by weight of catalyst, and 165-250 parts by weight of a single dehydrated terminal hydroxyl epoxidized polybutadiene resin;

[0009] The B component is prepared from the following raw materials in parts by weight:

[0010] 2-3 parts by weight of KH-550, 1-8 parts by weight of 3,5-dimethylthiotoluenediamine, 8-18 parts by weight of 651 polyamide curing agent, 1-8 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, and 25-40 parts by weight of heavy calcium carbonate filler.

[0011] Preferably, the polyether polyol is selected from one or more of polyoxypropylene glycol with a molecular weight of 2000 or 3000, polytetramethylene glycol with a molecular weight of 1000 or 2000, glycerol, MN-1000 or MN-500.

[0012] Preferably, the isocyanate is selected from one or more of toluene diisocyanate TDI-100 or TDI-80, diphenylmethane diisocyanate MDI-50 or liquefied MDI, isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

[0013] Preferably, the hydroxy-terminated epoxidized polybutadiene resin is selected from one or more of Poly bd 600E and Poly bd 605E.

[0014] Preferably, the catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate.

[0015] The present invention also provides a method for preparing a high-toughness two-component epoxy adhesive, comprising the following steps:

[0016] Step S1: preparing a soft segment product A1;

[0017] Step S101: 30-60 parts by weight of polyether polyol is placed in a reaction kettle, and dehydrated at 100-130° C. for 2-4 hours, and 35-55 parts by weight of isocyanate and 0.2-1.0 parts by weight of catalyst are added, and reacted at 80-100° C. for 4-8 hours.

[0018] Step S102: adding 165-250 parts by weight of a dehydrated hydroxyl-terminated epoxidized polybutadiene resin, and reacting at 80-100° C. for 4-8 hours, and the obtained product is a light yellow viscous liquid A1;

[0019] Step S2: adding 12-30 parts by weight of epoxy resin E51, 3-15 parts by weight of tetrafunctional epoxy resin AG80, 5-18 parts by weight of flexible segment product A1, and 50-70 parts by weight of heavy calcium carbonate filler into a high-speed planetary stirrer, and maintaining vacuum stirring for 2 hours to obtain component A;

[0020] Step S3: Add 2-3 parts by weight of KH-550, 1-8 parts by weight of 3,5-dimethylthiotoluenediamine, 8-18 parts by weight of 651 polyamide curing agent, 1-8 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, and 25-40 parts by weight of heavy calcium carbonate filler into a high-speed planetary stirrer, maintain vacuum stirring for 2 hours, and obtain component B.

[0021] Step S4: Mix the prepared component A and component B in a volume ratio of 2:1 to obtain a high-toughness two-component epoxy adhesive.

[0022] Preferably, in the preparation of the flexible segment product A1, after the reaction of the terminal hydroxyl epoxidized polybutadiene resin, a slightly excessive amount of isocyanate can be added, the content of which is controlled at 0.02-0.1%, and then polyether polyol or castor oil is added to consume the remaining isocyanate to increase the degree of crosslinking, thereby reducing the effect of the long-chain synthetic compound on the strength.

[0023] The technical solution of the present invention has the following beneficial effects:

[0024] The present invention successfully improves the toughness of the epoxy adhesive by introducing a flexible segment modification into the epoxy adhesive. This modification method enables the curing agent to be embedded in the cross-linked network of the epoxy to form a dense and loose two-phase structure, thereby improving the toughness while having little effect on the heat resistance and strength of the epoxy.

[0025] In the process of preparing the flexible segment of the present invention, the linear structure of the flexible segment product A1 can be changed by adding multifunctional polyether or bio-oil, thereby increasing the degree of crosslinking, thereby reducing the influence on the heat resistance and strength of epoxy, and achieving further optimization of performance.

[0026] The high-toughness two-component epoxy adhesive of the present invention not only maintains good toughness, but also exhibits excellent tensile strength and hardness. Compared with the prior art, the adhesive of the present invention has a significant improvement in elongation at break, which indicates that it has better performance when subjected to impact and deformation, and is suitable for a wider range of industrial application scenarios.

[0027] Molecular weight control: The present invention controls the molecular weight of the reaction product by adjusting the content of isocyanate, and can also adjust the content of polyether polyol and terminal hydroxyl epoxidized polybutadiene resin as needed, thereby optimizing the performance of the adhesive.

[0028] Performance improvement: The high-toughness two-component epoxy adhesive prepared by the present invention performs well in hardness, tensile strength and elongation at break. Compared with the prior art, the adhesive of the present invention has a significant improvement in elongation at break, which indicates that it has better performance when subjected to impact and deformation, and is suitable for a wider range of industrial application scenarios.

[0029] The adhesive of the present invention has no solvent added, is more environmentally friendly, and meets the requirements of modern industry for environmental protection and health. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the reaction between isocyanate and hydroxyl group of the present invention;

[0031] Figure 2 Schematic diagram of the ring-opening reaction of epoxy group and primary amine in the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] Reference Figure 1 to Figure 2 The present invention provides a method for preparing a high-toughness two-component epoxy adhesive, comprising the following steps:

[0035] Step 1: Preparation of flexible segments:

[0036] 50 g of 2000 molecular weight polytetrahydrofuran diol was placed in a reaction kettle, dehydrated at 110° C. for 3 h, 40 g of TDI-80 and 0.2 g of dibutyltin dilaurate were added, reacted at 90° C. for 4 h, and then 218.9 g of the separately dehydrated terminal hydroxyl epoxidized polybutadiene resin 600E was added, and the reaction was continued for another 4 h to obtain a light yellow viscous liquid A1;

[0037] Step 2: Preparation of epoxy adhesive:

[0038] 24g of epoxy resin E51, 8g of epoxy resin AG80, and 8 parts of flexible segment product A1 were stirred in vacuum for 30 minutes, and then 60 parts of heavy calcium carbonate were added to a high-speed planetary stirrer. After vacuum stirring for 2 hours, component A was obtained.

[0039] 3g KH-550, 2g 3,5-dimethylthiotoluenediamine, and 14g 651 polyamide curing agent were stirred in vacuum for 30 minutes, and then 1g 2,4,6-tris(dimethylaminomethyl)phenol was added, and finally 30 parts of heavy calcium carbonate were added, and the mixture was added into a high-speed planetary stirrer, and the mixture was stirred in vacuum for 2 hours to obtain component B;

[0040] Finally, the prepared component A and component B are mixed in a volume ratio of 2:1 to obtain a high-toughness two-component epoxy adhesive.

[0041] Example 2

[0042] The present invention provides a method for preparing a high-toughness two-component epoxy adhesive, comprising the following steps:

[0043] Step 1: Preparation of flexible segments:

[0044] 50 g of 2000 molecular weight polyoxypropylene glycol was placed in a reaction kettle, dehydrated at 110° C. for 3 h, 48 g of dicyclohexylmethane diisocyanate and 0.2 g of dibutyltin dilaurate were added, reacted at 90° C. for 4 h, 172.84 g of the separately dehydrated terminal hydroxyl epoxidized polybutadiene resin 605E was added, and the reaction was continued for 4 h, and finally 5 g of MN-1000 was added, and the reaction was continued for 3 h to obtain a light yellow viscous liquid A1;

[0045] Step 2: Preparation of epoxy adhesive:

[0046] 22g of epoxy resin E51, 8g of epoxy resin AG80, and 10 parts of flexible segment product A1 were stirred in vacuum for 30min, and then 60 parts of heavy calcium carbonate were added to a high-speed planetary stirrer. After vacuum stirring for 2h, component A was obtained.

[0047] To facilitate performance comparison, the preparation of component B is consistent with that of Example 1;

[0048] Finally, the prepared component A and component B are mixed in a volume ratio of 2:1 to obtain a high-toughness two-component epoxy adhesive.

[0049] Example 3

[0050] The present invention provides a method for preparing a high-toughness two-component epoxy adhesive, comprising the following steps:

[0051] Step 1: Preparation of flexible segments:

[0052] 32 g of 2000 molecular weight polytetrahydrofuran diol was placed in a reaction kettle, dehydrated at 110° C. for 3 h, 50 g of liquefied MDI and 0.2 g of dibutyltin dilaurate were added, reacted at 90° C. for 4 h, and then 171.61 g of the separately dehydrated terminal hydroxyl epoxidized polybutadiene resin 605E was added, and the reaction was continued for another 4 h to obtain a light yellow viscous liquid A1;

[0053] Step 2: Preparation of epoxy adhesive

[0054] 22g of epoxy resin E51, 8g of epoxy resin AG80, and 10 parts of flexible segment product A1 were stirred in vacuum for 30min, and then 60 parts of heavy calcium carbonate were added to a high-speed planetary stirrer. After vacuum stirring for 2h, component A was obtained.

[0055] To facilitate performance comparison, the formulation of component B is consistent with that of Example 1.

[0056] Finally, the prepared component A and component B are mixed in a volume ratio of 2:1 to obtain a high-toughness two-component epoxy adhesive.

[0057] Comparative Example 1

[0058] In the comparative example, the flexible segment was directly deleted to prepare an epoxy adhesive as a reference.

[0059] 32g of epoxy resin E51 and 8g of epoxy resin AG80 were stirred in vacuum for 30min, and then 60 parts of heavy calcium carbonate were added to a high-speed planetary stirrer. After vacuum stirring for 2h, component A was obtained.

[0060] 3g KH-550, 4g 3,5-dimethylthiotoluenediamine, and 12g 651 polyamide curing agent were stirred under vacuum for 30 minutes, and then 1g 2,4,6-tris(dimethylaminomethyl)phenol was added. Finally, 30 parts of heavy calcium carbonate were added, and the mixture was added to a high-speed planetary stirrer. After vacuum stirring for 2 hours, component B was obtained.

[0061] Performance Testing

[0062] The two-component epoxy adhesives of Examples 1-3 and Comparative Example 1 were respectively subjected to performance tests.

[0063] Shear strength test: Tested in accordance with ISO 4587 standard;

[0064] Tensile strength test: Tested in accordance with ASTM D412 standard;

[0065] Hardness test: Tested in accordance with ISO 7619-1 standard.

[0066] The test results of the examples are shown in Table 1 below:

[0067] Table 1

[0068] project Example 1 Example 2 Example 3 Comparative Example 1 Hardness (Shore D) 72D 70D 80D 85D Tensile strength(Mpa) 11.5 9.9 14.7 18.3 Elongation at break (%) 25.8 30.1 17.6 1.8

[0069] It can be seen from Table 1 that the high-toughness two-component epoxy adhesive prepared by the present invention has hardness and tensile strength similar to those of comparative example 1, and the elongation is also significantly improved. In the flexible segment of Example 2, the isocyanate raw material does not contain a benzene ring, so the flexibility is the highest, but a trifunctional polyether is added during the synthesis process, which has a certain tensile strength and hardness.

[0070] It can be seen from the above embodiments that the present invention successfully improves the toughness of the epoxy adhesive by introducing a flexible segment modification into the epoxy adhesive. This modification method enables the curing agent to be embedded in the cross-linked network of the epoxy to form a two-phase structure that is both dense and loose, thereby improving the toughness while having little effect on the heat resistance and strength of the epoxy.

[0071] In the process of preparing the flexible segment of the present invention, the linear structure of the flexible segment product A1 can be changed by adding multifunctional polyether or bio-oil, thereby increasing the degree of crosslinking, thereby reducing the influence on the heat resistance and strength of epoxy, and achieving further optimization of performance.

[0072] The high-toughness two-component epoxy adhesive of the present invention not only maintains good toughness, but also exhibits excellent tensile strength and hardness. Compared with the prior art, the adhesive of the present invention has a significant improvement in elongation at break, which indicates that it has better performance when subjected to impact and deformation, and is suitable for a wider range of industrial application scenarios.

[0073] Molecular weight control: The present invention controls the molecular weight of the reaction product by adjusting the content of isocyanate, and can also adjust the content of polyether polyol and terminal hydroxyl epoxidized polybutadiene resin as needed, thereby optimizing the performance of the adhesive.

[0074] Performance improvement: The high-toughness two-component epoxy adhesive prepared by the present invention performs well in hardness, tensile strength and elongation at break. Compared with the prior art, the adhesive of the present invention has a significant improvement in elongation at break, which indicates that it has better performance when subjected to impact and deformation, and is suitable for a wider range of industrial application scenarios.

[0075] The adhesive of the present invention has no solvent added, is more environmentally friendly, and meets the requirements of modern industry for environmental protection and health.

[0076] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A high-toughness two-component epoxy adhesive, characterized in that: The epoxy adhesive consists of two components, A and B, with the volume ratio of component A to component B being 2:1; The A component is prepared from the following raw materials in parts by weight: 12-30 parts by weight of epoxy resin E51, 3-15 parts by weight of tetrafunctional epoxy resin AG80, 5-18 parts by weight of soft segment product A1, 50-70 parts by weight of heavy calcium carbonate filler; wherein the raw materials for preparing the soft segment product A1 are: 30-60 parts by weight of polyether polyol, 35-55 parts by weight of isocyanate, 0.2-1 parts by weight of catalyst, 165-250 parts by weight of hydroxyl-terminated epoxidized polybutadiene resin; The B component is prepared from the following raw materials in parts by weight: 2-3 parts by weight of KH-550, 1-8 parts by weight of 3,5-dimethylthiotoluenediamine, 8-18 parts by weight of 651 polyamide curing agent, 1-8 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, and 25-40 parts by weight of heavy calcium carbonate filler.

2. The high-toughness two-component epoxy adhesive according to claim 1, characterized in that: The polyether polyol is selected from one or more of polyoxypropylene glycol with a molecular weight of 2000 or 3000, polytetrahydrofuran diol with a molecular weight of 1000 or 2000, glycerol, MN-1000 or MN-500.

3. The high-toughness two-component epoxy adhesive according to claim 1, characterized in that: The isocyanate is selected from one or more of toluene diisocyanate TDI-100 or TDI-80, diphenylmethane diisocyanate MDI-50 or liquefied MDI, isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate.

4. The high-toughness two-component epoxy adhesive according to claim 1, characterized in that: The hydroxyl-terminated epoxidized polybutadiene resin is selected from one or more of Poly bd 600E and Poly bd 605E.

5. The high-toughness two-component epoxy adhesive according to claim 1, characterized in that: The catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, and dibutyltin diacetate.

6. A method for preparing the high-toughness two-component epoxy adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: preparing a soft segment product A1; Step S101: 30-60 parts by weight of polyether polyol is placed in a reaction kettle, and dehydrated at 100-130° C. for 2-4 hours, and 35-55 parts by weight of isocyanate and 0.2-1.0 parts by weight of catalyst are added, and reacted at 80-100° C. for 4-8 hours. Step S102: adding 165-250 parts by weight of hydroxyl-terminated epoxidized polybutadiene resin, reacting at 80-100° C. for 4-8 hours, and obtaining a product of light yellow viscous liquid A1; Step S2: adding 12-30 parts by weight of epoxy resin E51, 3-15 parts by weight of tetrafunctional epoxy resin AG80, 5-18 parts by weight of flexible segment product A1, and 50-70 parts by weight of heavy calcium carbonate filler into a high-speed planetary stirrer, and maintaining vacuum stirring for 2 hours to obtain component A; Step S3: Add 2-3 parts by weight of KH-550, 1-8 parts by weight of 3,5-dimethylthiotoluenediamine, 8-18 parts by weight of 651 polyamide curing agent, 1-8 parts by weight of 2,4,6-tris(dimethylaminomethyl)phenol, and 25-40 parts by weight of heavy calcium carbonate filler into a high-speed planetary stirrer, maintain vacuum stirring for 2 hours, and obtain component B. Step S4: Mix the prepared component A and component B in a volume ratio of 2:1 to obtain a high-toughness two-component epoxy adhesive.

7. The method of making a high-toughness two-component epoxy adhesive according to claim 6, characterized in that: In the preparation of the flexible segment product A1, after the terminal hydroxyl epoxidized polybutadiene resin reacts, a slight excess of isocyanate can be added, with the content controlled at 0.02-0.1%, and then polyether polyol or castor oil is added to consume the remaining isocyanate to increase the degree of crosslinking, thereby reducing the influence of long-chain synthetics on strength.