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CN-121975475-A - Polyurethane adhesive and preparation method and application thereof

CN121975475ACN 121975475 ACN121975475 ACN 121975475ACN-121975475-A

Abstract

The invention discloses a polyurethane adhesive and a preparation method and application thereof. The polyurethane adhesive comprises a prepolymer, toluene triisocyanate TTI, a compound regulator and a carboxyl modifier, wherein the preparation method of the prepolymer comprises the step of preparing the prepolymer by reacting dimethylolpropionic acid, isocyanate and polyalcohol, the compound regulator comprises bismuth isooctanoate and caprolactam, and the carboxyl modifier is one or a mixture of more than two of succinic acid, adipic acid and citric acid. The polyurethane adhesive has the advantages of remarkably shortening the opening time to 10-25min, adapting to the rapid construction requirement, improving the tensile shear strength by more than 15% compared with the traditional polyurethane adhesive, improving the interfacial peel strength by more than 20% and improving the breaking elongation by more than 450% when the metal substrate is bonded by 15-22N/mm.

Inventors

  • LIN ZHIHUI
  • JIN PEIYAO
  • LI LIQUAN
  • SHEN YONGJUN
  • LI JING
  • WANG MAOYU
  • XI PENG
  • CHEN FEI

Assignees

  • 融通资源安徽有限公司

Dates

Publication Date
20260505
Application Date
20251226

Claims (10)

  1. 1. The polyurethane adhesive is characterized by comprising a prepolymer, toluene triisocyanate TTI, a composite regulator and a carboxyl modifier; The preparation method of the prepolymer comprises the steps of preparing the prepolymer by reacting dimethylolpropionic acid, isocyanate and polyalcohol, wherein the isocyanate is toluene diisocyanate TDI or diphenylmethane diisocyanate MDI; The composite regulator comprises bismuth isooctanoate and caprolactam; the carboxyl modifier is selected from one or more than two of succinic acid, adipic acid and citric acid; wherein the formula of each component comprises 100 parts by mass of polyol, 85-200 parts by mass of isocyanate, 0.5-5 parts by mass of dimethylolpropionic acid DMPA, 1-10 parts by mass of TTI, 0.1-1 part by mass of composite modifier and 0.5-5 parts by mass of carboxyl modifier.
  2. 2. The polyurethane adhesive according to claim 1, wherein the composite regulator comprises 20-60% of bismuth isooctanoate by mass and 40-80% of caprolactam by mass.
  3. 3. The polyurethane adhesive according to claim 1, wherein the preparation of the prepolymer comprises the preparation of the prepolymer by the mixed reaction of isocyanate, polyol and dimethylolpropionic acid under the protection of inert gas at 70-95 ℃.
  4. 4. The polyurethane adhesive of claim 1, wherein the polyol is selected from polyester polyols having a number average molecular weight of 1000 to 3000 or polyether polyols having a number average molecular weight of 1000 to 2000.
  5. 5. The polyurethane adhesive of claim 1, wherein the polyurethane adhesive has an open time of 10 to 25 minutes.
  6. 6. The polyurethane adhesive of claim 1, wherein the polyurethane adhesive has a tensile shear strength of 6-14 MPa and an interfacial peel strength of 15-22N/mm when adhered to a metal substrate, the metal substrate being aluminum or steel.
  7. 7. The preparation method of the polyurethane adhesive according to claim 1, which is characterized by comprising the steps of uniformly mixing a prepolymer, a TTI, a composite regulator and a carboxyl modifier, and heating to 60-85 ℃ for reaction for 0.8-2.5h.
  8. 8. Use of the polyurethane adhesive prepared by the method of claim 7 for bonding metal substrates, which are aluminum or steel, characterized in that the use comprises curing after coating the surface of the metal substrate to be bonded with the polyurethane adhesive prepared by the method of claim 7.
  9. 9. Use according to claim 7, characterized in that the coating thickness is 0.1-0.5mm.
  10. 10. The use according to claim 7, wherein the curing is at 90-130 ℃ for 0.8-2.5h, or at 30-55 ℃ for 10-20h.

Description

Polyurethane adhesive and preparation method and application thereof Technical Field The invention belongs to the technical field of chemical materials, and particularly relates to a polyurethane adhesive, a preparation method thereof and application of the adhesive in a rapid bonding scene of a metal substrate. Background Polyurethane adhesives are increasingly used in the fields of automobile manufacturing, mechanical assembly, metal processing and the like due to wide substrate applicability, excellent adhesive strength and flexibility. In particular, in structural bonding of metal members (aluminum, steel, etc.), it is necessary to satisfy requirements of high strength, high interface stability, and efficient construction at the same time. The polyurethane adhesive needs to meet the requirements of high strength, high interface stability and construction efficiency in metal structure adhesion. In the prior art, toluene Triisocyanate (TTI) is used as a cross-linking agent to improve the tensile shear strength, but the opening time (also called open time, which means the time interval from the completion of gluing to the loss of fluidity of a glue layer and the failure of effective bonding after the glue layer is coated on the surface of an adherend) is too long (30-60 min), so that the adhesive is difficult to adapt to the rapid construction scenes such as batch assembly of automobile parts, emergency maintenance of equipment and the like. In addition, conventional methods for shortening the open time (e.g., increasing the curing temperature or increasing the amount of catalyst) tend to cause problems such as excessive crosslinking, reduced flexibility, etc. Disclosure of Invention Aiming at the defects or shortcomings in the prior art, the invention provides a polyurethane adhesive. Therefore, the polyurethane adhesive provided by the invention comprises a prepolymer, toluene triisocyanate TTI, a composite regulator and a carboxyl modifier; The preparation method of the prepolymer comprises the steps of preparing the prepolymer by reacting dimethylolpropionic acid, isocyanate and polyalcohol, wherein the isocyanate is toluene diisocyanate TDI or diphenylmethane diisocyanate MDI; The composite regulator comprises bismuth isooctanoate and caprolactam; the carboxyl modifier is selected from one or more than two of succinic acid, adipic acid and citric acid; Wherein the components are 100 parts by mass of polyol, 85-200 parts by mass of isocyanate, 0.5-5 parts by mass of dimethylolpropionic acid DMPA, 1-10 parts by mass of TTI, 0.1-1 part by mass of composite modifier and 0.5-5 parts by mass of carboxyl modifier. In the alternative scheme, in the composite regulator, the content of bismuth isooctanoate is 20-60% by mass, and the content of caprolactam is 40-80% by mass. Alternatively, the preparation of the prepolymer comprises the steps of preparing the prepolymer by mixing and reacting isocyanate, polyol and dimethylolpropionic acid under the protection of inert gas at 70-95 ℃. Alternatively, the polyol is selected from polyester polyols having a number average molecular weight of 1000 to 3000 or polyether polyols having a number average molecular weight of 1000 to 2000. Alternatively, the polyurethane adhesive has an opening time of 10-25min. Alternatively, the tensile shear strength of the polyurethane adhesive is 6-14 MPa, the interfacial peel strength of the polyurethane adhesive is 15-22N/mm when the polyurethane adhesive is adhered to a metal substrate, and the metal substrate is aluminum or steel. The preparation method of the polyurethane adhesive comprises the steps of uniformly mixing a prepolymer, a TTI (transmission time interval), a composite regulator and a carboxyl modifier, and then heating to 60-85 ℃ for reaction for 0.8-2.5h. The polyurethane adhesive can be used for bonding metal substrates, wherein the metal substrates are aluminum or steel, and the specific application comprises the steps of coating the surface of the metal substrates to be bonded with the polyurethane adhesive prepared by the method of claim 7 and then curing. Alternatively, the coating thickness is 0.1-0.5mm. The curing is performed at 90-130 ℃ for 0.8-2.5h or at 30-55 ℃ for 10-20h. The polyurethane adhesive has the advantages of remarkably shortening the opening time to 10-25min, adapting to the rapid construction requirement, improving the tensile shear strength by more than 15% compared with the traditional polyurethane adhesive (such as pulida 8891, tianyang 5210 and Yi Likai Tafelix-998), improving the interfacial peel strength by more than 20% and improving the breaking elongation by more than 450% when being adhered to a metal substrate, along with obviously shortening the opening time to 10-25 min. Detailed Description Unless specifically stated otherwise, scientific and technical terms herein have been understood based on the knowledge of one of ordinary skill in the relevant art. The polyurethane adhesive