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CN-121991614-A - High-flexibility tear-resistant epoxy structural adhesive and preparation method and application thereof

CN121991614ACN 121991614 ACN121991614 ACN 121991614ACN-121991614-A

Abstract

The invention provides a high-flexibility tear-resistant epoxy structural adhesive, a preparation method and application thereof, wherein the epoxy structural adhesive is formed by mixing a component A and a component B, the component A comprises, by weight, 34-70% of modified epoxy resin, 5-30% of bisphenol A epoxy resin, 2-6% of benzyl alcohol, 8-15% of epoxy reactive diluent, 0.2-1.5% of defoaming agent, 1-5% of thixotropic agent, 5-40% of filler and 1-4% of epoxy color paste, and the component B comprises, by weight, 55-75% of polyetheramine, 5-15% of bisphenol A epoxy resin, 5-10% of benzyl alcohol and 10-20% of dodecylphenol, by weight, based on the total weight of the component B. The mixing mass ratio of the component A to the component B is (3.7-7) 1. The invention combines the modified epoxy resin and the bisphenol A epoxy resin and an optimized curing system, so that the structural adhesive can remarkably improve the flexibility and tear resistance while maintaining the high strength of the epoxy resin, and is suitable for structural bonding in the fields of construction, automobiles, electronics and the like.

Inventors

  • FAN ZHIKANG

Assignees

  • 福建沧晟化工有限公司

Dates

Publication Date
20260508
Application Date
20260129
Priority Date
20251119

Claims (10)

  1. 1. The high-flexibility tear-resistant epoxy structural adhesive is characterized by being formed by mixing a component A and a component B; the component A takes the total weight of the component A as a reference, and comprises the following components in percentage by weight: 34-70% of modified epoxy resin, 5-30% of bisphenol A type epoxy resin, 2-6% of benzyl alcohol, 8-15% of epoxy reactive diluent, 0.2-1.5% of defoamer, 1-5% of thixotropic agent, 5-40% of filler and 1-4% of epoxy color paste; the component B comprises the following components in percentage by weight based on the total weight of the component B: 55-75% of polyether amine, 5-15% of bisphenol A epoxy resin, 5-10% of benzyl alcohol and 10-20% of dodecylphenol.
  2. 2. The high-flexibility tear-resistant epoxy structural adhesive according to claim 1, wherein the mixing mass ratio of the A component and the B component is (3.7-7): 1.
  3. 3. The high flexibility tear resistant epoxy structural adhesive of claim 1, wherein the defoamer is comprised of a silicone defoamer and a polymer defoamer, wherein the silicone defoamer is present in an amount of 0.1 to 1%, the polymer defoamer is present in an amount of 0.1 to 0.5%, and the defoamer is present in an amount of 0.2 to 1.5% based on the total weight of the a component.
  4. 4. The high-flexibility tear-resistant epoxy structural adhesive according to claim 1, wherein the epoxy reactive diluent is any one or more of benzyl glycidyl ether, butyl glycidyl ether and C12-14 alkyl glycidyl ether, and the filler is any one or more of silicon micropowder, heavy calcium powder, talcum powder and barium sulfate.
  5. 5. The highly flexible tear resistant epoxy structural adhesive of claim 1, wherein the thixotropic agent is fumed silica or bentonite.
  6. 6. The high flexibility tear resistant epoxy structural adhesive of claim 1, wherein the modified epoxy resin is a polyurethane modified epoxy resin or a polyether modified epoxy resin.
  7. 7. The high-flexibility tear-resistant epoxy structural adhesive according to claim 6, wherein the epoxy equivalent of the polyurethane modified epoxy resin is 410-470g/eq, the viscosity is 20000-60000 mPa.s, the epoxy equivalent of the polyether modified epoxy resin is 360-390g/eq, and the viscosity is 6000-15000 mPa.s.
  8. 8. The high-flexibility tear-resistant epoxy structural adhesive according to claim 1, wherein the epoxy color paste comprises the following components in percentage by weight based on the total weight of the epoxy color paste: 30-50% of bisphenol A type epoxy resin, 5-10% of epoxy reactive diluent, 2-3% of dispersing agent, 39.5-61% of titanium pigment and 0.5-2% of carbon black.
  9. 9. A method of preparing the highly flexible tear resistant epoxy structural adhesive of any one of claims 1-8, comprising the steps of: (1) The preparation of the component A comprises the steps of adding modified epoxy resin, bisphenol A epoxy resin, benzyl alcohol and epoxy reactive diluent into a reaction kettle according to the proportion, stirring and mixing uniformly at 40-60 ℃, then adding defoamer, thixotropic agent, filler and epoxy color paste, continuing to disperse until the fineness is less than 30 microns, and filtering and discharging the 120-mesh cloth; (2) The preparation of the component B comprises the steps of adding polyether amine into a reaction kettle according to the proportion for dispersing, then uniformly mixing benzyl alcohol and bisphenol A epoxy resin, slowly adding the mixture into the reaction kettle, stirring and dispersing at 50-60 ℃ and carrying out heat preservation reaction for 2-4 hours, finally adding dodecylphenol, and continuously stirring until the mixture is uniform; (3) Mixing and curing, namely mixing the component A obtained in the step (1) and the component B obtained in the step (2) according to the mass ratio of (3.7-7): 1, uniformly stirring, and curing at room temperature to obtain the epoxy structural adhesive.
  10. 10. Use of a highly flexible tear resistant epoxy structural adhesive as defined in any one of claims 1 to 8 as a structural adhesive material.

Description

High-flexibility tear-resistant epoxy structural adhesive and preparation method and application thereof Technical Field The invention belongs to the technical field of structural adhesives, and particularly relates to a high-flexibility anti-tearing epoxy structural adhesive, and a preparation method and application thereof. Background Epoxy resin structural adhesives have become an indispensable key bonding material in high-end industrial fields such as aerospace, automobile manufacturing, wind power generation, building structures and the like by virtue of excellent mechanical properties, outstanding durability, good chemical corrosion resistance and wide adaptability to various substrates (such as metal, concrete, composite materials and the like). The curing mechanism depends on the formation of a three-dimensional network structure by crosslinking of epoxy groups and a curing agent, so that the material is endowed with extremely high rigid bonding strength. However, due to the high crosslinking density and limited segment movement, the traditional epoxy resin system often has the characteristics of high hardness (about 80 Shore D hardness) and high brittleness after curing. This characteristic results in poor impact resistance, insufficient fatigue resistance and low elongation at break. In practical application, especially in the bonding occasion of heterogeneous materials which bear dynamic load, vibration impact or have thermal expansion coefficient difference, stress concentration is easy to generate in the material, microcrack is initiated and rapidly expands, and finally, the bonding joint is caused to generate sudden brittle fracture under the condition of being far lower than theoretical load, so that obvious potential safety hazard exists. In order to break through the brittle bottleneck of epoxy resin, the industry has developed various toughening techniques, mainly including liquid rubber toughening, thermoplastic polymer toughening, core-shell polymer (CSP) toughening, nanoparticle toughening and the like. Although these methods improve the toughness of the material to some extent, the contradiction of the mutual restriction of strength and toughness is generally faced, namely the toughness, the strength and the heat resistance are often reduced along with the toughening modification. More importantly, tear resistance is a key indicator for evaluating the ability of a material to resist crack propagation, requiring adhesives that have not only high elongation at break, but also high tear strength to efficiently absorb and disperse energy. The existing toughened epoxy adhesive still often has the defects of burst damage and insufficient energy dissipation capability under the action of continuous or repeated tearing stress. In view of the above, the invention provides a high-flexibility anti-tearing epoxy structural adhesive, a preparation method and application thereof, which can effectively solve the contradiction between strength and toughness, and can maintain the inherent high strength, high modulus and good heat resistance of epoxy resin while obviously improving the elongation at break and the anti-tearing strength. Disclosure of Invention Aiming at the problems that the traditional epoxy structural adhesive is large in brittleness and insufficient in tear resistance, and the strength and toughness are difficult to be considered in the existing toughening technology, the invention provides the high-flexibility tear-resistant epoxy structural adhesive, and the preparation method and the application thereof are used for solving the technical defects. The technical scheme adopted for solving the technical problems is as follows: in a first aspect, the invention provides a high-flexibility tear-resistant epoxy structural adhesive, which is formed by mixing a component A and a component B; the component A comprises the following components in percentage by weight based on the total weight of the component A: 34-70% of modified epoxy resin, 5-30% of bisphenol A type epoxy resin, 2-6% of benzyl alcohol, 8-15% of epoxy reactive diluent, 0.2-1.5% of defoamer, 1-5% of thixotropic agent, 5-40% of filler and 1-4% of epoxy color paste; The component B comprises the following components in percentage by weight based on the total weight of the component B: 55-75% of polyether amine, 5-15% of bisphenol A epoxy resin, 5-10% of benzyl alcohol and 10-20% of dodecylphenol. Preferably, the mixing mass ratio of the component A to the component B is (3.7-7): 1. Preferably, the defoaming agent consists of an organic silicon defoaming agent and a polymer defoaming agent, wherein the content of the organic silicon defoaming agent is 0.1-1% based on the total weight of the component A, the content of the polymer defoaming agent is 0.1-0.5%, and the total content of the defoaming agent is 0.2-1.5%. Preferably, the epoxy reactive diluent is any one or more of benzyl glycidyl ether, butyl glycidyl ether and C12-1