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CN-122012005-A - Bi-component polyurethane adhesive and preparation method and application thereof

CN122012005ACN 122012005 ACN122012005 ACN 122012005ACN-122012005-A

Abstract

The invention discloses a bi-component polyurethane adhesive and a preparation method and application thereof, wherein the adhesive comprises, by weight, 15-30 parts of hydroxyl-terminated polybutadiene, 20-40 parts of polyester polyol, 5-15 parts of epoxy modified polyether polyol, 1-5 parts of phosphate, 1-5 parts of small-molecule diol chain extender, 2-10 parts of silane coupling agent, 1-5 parts of thixotropic agent, 20-50 parts of filler, 5-15 parts of flame retardant and 0.1-0.5 part of catalyst, and the B component comprises 60-80 parts of polyisocyanate and 20-40 parts of polyurethane prepolymer. The bi-component polyurethane adhesive is used for bonding between SMCs or metal, has high strength and high elasticity, balances the difference of the thermal expansion coefficients of the SMCs and the metal, and can realize the reliable bonding of the SMCs without complex surface treatment.

Inventors

  • DING YU
  • WANG TINGTING

Assignees

  • 江苏长能节能新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (10)

  1. 1. The bi-component polyurethane adhesive is characterized by comprising, by weight, 15-30 parts of hydroxyl-terminated polybutadiene, 20-40 parts of polyester polyol, 5-15 parts of epoxy modified polyether polyol, 1-5 parts of phosphate, 1-5 parts of small-molecule diol chain extender, 2-10 parts of silane coupling agent, 1-5 parts of thixotropic agent, 20-50 parts of filler, 5-15 parts of flame retardant and 0.1-0.5 part of catalyst, wherein the B component comprises 60-80 parts of polyisocyanate and 20-40 parts of polyurethane prepolymer.
  2. 2. The two-component polyurethane adhesive according to claim 1, wherein the phosphate ester is one or more of trimethyl phosphate, triethyl phosphate and tributyl phosphate.
  3. 3. The two-component polyurethane adhesive of claim 1, wherein the hydroxyl-terminated polybutadiene has a hydroxyl number of 35 to 115 mg KOH/g.
  4. 4. The two-component polyurethane adhesive of claim 1, wherein the polyester polyol is a dimer acid modified polyester polyol having a molecular weight of 2000-2500.
  5. 5. The two-component polyurethane adhesive of claim 1, wherein the epoxy modified polyether polyol has an epoxy value of 0.08 to 0.12 mol/100g.
  6. 6. The two-component polyurethane adhesive of claim 1, wherein the silane coupling agent is one or more of gamma-aminopropyl triethoxysilane, gamma-glycidoxypropyl trimethoxysilane.
  7. 7. The two-component polyurethane adhesive of claim 1, wherein the polyisocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, or hexamethylene diisocyanate.
  8. 8. The two-component polyurethane adhesive of claim 1, wherein the polyurethane prepolymer is an MDI-type prepolymer having an NCO content of 10% to 11%.
  9. 9. A method for preparing the two-component polyurethane adhesive according to any one of claims 1 to 8, which is characterized by comprising the following steps: (1) The component A is prepared by adding hydroxyl-terminated polybutadiene, polyester polyol, epoxy modified polyether polyol, phosphate and micromolecular dihydric alcohol chain extender into a reaction kettle, dehydrating under vacuum, cooling to below 50 ℃, adding a silane coupling agent, a thixotropic agent, a filler, a flame retardant and a catalyst, uniformly stirring, discharging and packaging to obtain the component A; (2) The preparation of the component B, namely adding polyisocyanate and polyurethane prepolymer into a reaction kettle, stirring and reacting at 60-70 ℃, cooling and packaging to obtain the component B; (3) The adhesive is prepared by uniformly mixing the component A and the component B when in use, and the double-component polyurethane adhesive is obtained.
  10. 10. Use of a two-component polyurethane adhesive according to any one of claims 1 to 8 in the adhesion of SMC to SMC or metal.

Description

Bi-component polyurethane adhesive and preparation method and application thereof Technical Field The invention relates to the technical field of adhesives, in particular to a bi-component polyurethane adhesive and a preparation method and application thereof. Background As a fiber reinforced thermosetting composite material, the Sheet Molding Compound (SMC) has the advantages of light weight, high strength, corrosion resistance, high design freedom and the like, and is widely applied to the fields of automobiles, aerospace, buildings and the like. In practical application, the SMC parts are often required to be connected and assembled with other SMC parts or metal parts, but the surface of the SMC has the problems of residual release agent, low surface energy and the like, so that the adhesion difficulty is high. Currently, common adhesives for SMC bonding include epoxy, acrylate, and polyurethane adhesives. The epoxy resin adhesive has high bonding strength but high brittleness after curing and poor impact resistance, the acrylic resin adhesive has high curing speed but high shrinkage and insufficient durability, and the polyurethane adhesive has excellent toughness, fatigue resistance and comprehensive mechanical properties, so that the epoxy resin adhesive becomes a preferable scheme for SMC bonding. However, the existing polyurethane adhesive has the defects of poor surface adaptability to SMC, complex surface treatment (such as polishing and bottom coating) to ensure the bonding effect, high thermal expansion coefficient difference when the SMC is bonded with different metal materials, easy internal stress generation under the thermal cycle condition to cause bonding failure, and difficulty in realizing high strength and high elasticity simultaneously. Chinese patent CN117106406A discloses a vegetable oil-based flame-retardant double-component polyurethane adhesive, wherein an adhesive substrate comprises SMC, metal and the like, the adhesive strength of aluminum sheets/aluminum sheets reaches more than 15MPa, the flame retardant performance is excellent, but the problem of stress caused by difference of thermal expansion coefficients of the SMC and the metal is not solved, and the delayed thermosensitive double-component polyurethane adhesive (CN 120209768A) disclosed by Beijing Gao Union New material Co., ltd is long in normal temperature operation time and is quickly cured after temperature rise, and the adhesive substrate comprises wood, SMC, metal and the like, and the problem of thermal stress adaptation of the SMC and the metal is not solved. Therefore, the development of the bi-component polyurethane adhesive which is suitable for the surface characteristics of the SMC, balances the thermal stress between the SMC and the metal and has high strength and high elasticity has important technical and application values. Disclosure of Invention The invention aims to provide a two-component polyurethane adhesive for bonding SMC and SMC or metal, which has high strength and high elasticity, balances the difference of the thermal expansion coefficients of the SMC and the metal, and realizes the reliable bonding of the SMC without complex surface treatment, and aims to provide a preparation method of the two-component polyurethane adhesive, and a third aim of the invention is to provide the application of the two-component polyurethane adhesive. The bi-component polyurethane adhesive comprises, by weight, 15-30 parts of hydroxyl-terminated polybutadiene, 20-40 parts of polyester polyol, 5-15 parts of epoxy modified polyether polyol, 1-5 parts of phosphate, 1-5 parts of small-molecule diol chain extender, 2-10 parts of silane coupling agent, 1-5 parts of thixotropic agent, 20-50 parts of filler, 5-15 parts of flame retardant and 0.1-0.5 part of catalyst, and the B component comprises 60-80 parts of polyisocyanate and 20-40 parts of polyurethane prepolymer. The component A and the component B in the double-component polyurethane adhesive are mixed according to the isocyanate index of 1-1.5. The mass ratio of the component A to the component B is 3:1-5:1. Preferably, the phosphate is one or more of trimethyl phosphate, triethyl phosphate and tributyl phosphate. The phosphate can reduce the system viscosity, improve the infiltration of the filler, effectively improve the dispersibility of the filler, simultaneously has strong infiltration capacity on common release agents, can effectively reduce the influence of the release agents on adhesion, and the groups of the phosphate can form stable bonds with the surface of the substrate, so that the chemical binding force with the substrate is effectively increased. Preferably, the hydroxyl-terminated polybutadiene has a hydroxyl value of 35-115 mg KOH/g and a molecular weight of 1000-3000. Too high a hydroxyl number or too low a molecular weight, the system becomes significantly brittle, and too low a hydroxyl number or too high a molecular weight, the bulk stren