Search

CN-121975477-A - Hot melt adhesive film with high bonding strength and preparation method thereof

CN121975477ACN 121975477 ACN121975477 ACN 121975477ACN-121975477-A

Abstract

The invention belongs to the technical field of hot melt adhesive films, and particularly relates to a hot melt adhesive film with high bonding strength and a preparation method thereof. The preparation method comprises the steps of (1) mixing o-vanillin-based bi-five-membered ring carbonic ester and phosphorus-containing diamine, carrying out polymerization reaction under a heating condition to obtain a prepolymer, and (2) carrying out vacuum defoaming treatment on the prepolymer, then coating the prepolymer into a film, solidifying, cooling and stripping the film to obtain the product. The invention utilizes the o-vanillin bio-based rigid framework and the Schiff base bond structure thereof to enhance cohesive energy and interface action, and simultaneously realizes essential flame retardance by introducing phosphorus elements into a polymer main chain in a covalent bond way. The obtained hot melt adhesive film has high tensile strength, high bonding strength, excellent flame retardance and good heat resistance and water resistance.

Inventors

  • Bin Jiachuo
  • WANG XUEMEI
  • WEN SHENG
  • HE JUXIANG
  • JIANG TING

Assignees

  • 张家界齐汇新材料有限公司

Dates

Publication Date
20260505
Application Date
20260409

Claims (10)

  1. 1. The preparation method of the hot melt adhesive film with high bonding strength is characterized by comprising the following steps of: (1) Mixing o-vanillin-based double five-membered ring carbonate and phosphorus-containing diamine, and carrying out polymerization reaction under the heating condition to obtain a prepolymer; (2) And (3) carrying out vacuum defoaming treatment on the prepolymer, then coating the prepolymer into a film, solidifying, cooling and stripping the film to obtain the hot melt adhesive film with high bonding strength.
  2. 2. The method for preparing a hot melt adhesive film with high adhesive strength according to claim 1, wherein the preparation process of the o-vanillin-based double five-membered ring carbonate in the step (1) is as follows: (a) Adding o-vanillin and 1, 8-octanediamine into ethanol, and carrying out reflux reaction under the action of glacial acetic acid to obtain o-vanillin bis-Schiff base diphenol; (b) Adding o-vanillin bis-Schiff base diphenol into epichlorohydrin, performing ring-opening reaction in the presence of a phase transfer catalyst, and then performing ring-closing reaction under the action of strong alkali to obtain o-vanillin bis-epoxy monomer; (c) Adding an o-vanillin-based double-oxygen monomer and a catalyst into N, N-dimethylformamide, and introducing carbon dioxide to perform cycloaddition reaction to obtain the o-vanillin-based double-five-membered cyclic carbonate.
  3. 3. The method of producing a hot melt adhesive film having a high adhesive strength according to claim 2, wherein the molar ratio of o-vanillin to 1, 8-octanediamine in the step (a) is (2-2.2): 1, and the time of the reflow reaction is 6-8 h.
  4. 4. The method for preparing a hot melt adhesive film with high adhesive strength according to claim 2, wherein the dosage ratio of the o-vanillin bis-schiff base diphenol, epichlorohydrin, phase transfer catalyst and strong base in the step (b) is 1 mmol (3-4) mL (0.05-0.06) mmol (2.5-3) and the phase transfer catalyst is tetrabutylammonium bromide, the strong base is sodium hydroxide or potassium hydroxide, the ring-opening reaction temperature is 70-80 ℃ and the time is 2-3 h, the ring-closing reaction temperature is 50-60 ℃ and the time is 4-6 h.
  5. 5. The method for preparing a hot melt adhesive film with high adhesive strength according to claim 2, wherein in the step (C), the molar ratio of the o-vanillin-based dioxygen monomer to the catalyst is 1 (0.05-0.06), the catalyst is tetrabutylammonium bromide, the pressure is kept at 1.0-2.0 MPa after carbon dioxide is introduced, and the cycloaddition reaction temperature is 100-110 ℃ and the time is 12-24 h.
  6. 6. The method for producing a hot melt adhesive film having high adhesive strength according to claim 1, wherein the process for producing the phosphorus-containing diamine in the step (1) is as follows: Adding methylphosphonic acid into dichloromethane, adding 3-amino-1-propanol and triethylamine under ice bath condition, and heating for reaction.
  7. 7. The method for preparing a hot melt adhesive film having high adhesive strength according to claim 6, wherein the molar ratio of methylphosphonic acid, 3-amino-1-propanol and triethylamine is 1 (2-2.2): 2-2.2, and the heating reaction is carried out at a temperature of 40-45 ℃ for a time of 4-6 h.
  8. 8. The method for preparing a hot melt adhesive film with high adhesive strength according to claim 1, wherein the molar ratio of the o-vanillin-based dicyclo carbonate to the phosphoric diamine in the step (1) is 1:1, the heating temperature is 90-100 ℃, and the polymerization time is 12-24 h.
  9. 9. The method for producing a hot-melt adhesive film having high adhesive strength according to claim 1, wherein the curing temperature in step (2) is 110 to 120 ℃ for 12 to 24 h.
  10. 10. A hot melt adhesive film having high adhesive strength, characterized by being produced by the production method as claimed in any one of claims 1 to 9.

Description

Hot melt adhesive film with high bonding strength and preparation method thereof Technical Field The invention belongs to the technical field of hot melt adhesive films, and particularly relates to a hot melt adhesive film with high bonding strength and a preparation method thereof. Background The hot melt adhesive film is used as a high-efficiency and environment-friendly solid adhesive, is coated after being heated and melted, can be quickly bonded after being cooled and solidified, and is widely applied to the fields of packaging, spinning, electronic assembly, automobile interior decoration, composite material lamination and the like. Conventional high performance hot melt adhesive films rely primarily on petroleum-based materials such as polyesters, polyamides, polyolefins and derivatives thereof and form polyurethane structures by reacting isocyanates with polyols to achieve excellent flexibility and bond strength. However, this technical route has the remarkable drawbacks of not being renewable on the one hand, not conforming to the concept of green sustainable development, and on the other hand, of being highly toxic and sensitive to moisture, of isocyanate monomers, the use and residues of which constitute a potential risk for safety in production operations and for the health and environmental protection of the end product. To address the above problems, non-isocyanate polyurethane (NIPU) technology has been developed. NIPU is generally prepared by ring-opening polymerization of cyclic carbonate and polyamine compound, isocyanate is not needed in the process, and the generated polymer main chain is rich in hydroxyl groups, so that the bonding performance and the material toughness are expected to be improved through hydrogen bonding. In recent years, researchers have attempted to replace petroleum-based raw materials with bio-based raw materials such as vegetable oils, lignin derivatives, vanillin, etc., in order to improve the environmental friendliness of the product. Meanwhile, in order to meet the severe requirements of the fields of electronics, transportation and the like on the flame retardance of materials, flame retardants (such as halogen-based, phosphorus-based, nitrogen-based or inorganic fillers) are often added into the adhesive. However, the physical blending addition mode is easy to cause migration and precipitation of the flame retardant, so that not only is the long-term flame retardant effect reduced, but also the transparency, mechanical property and interface bonding reliability of the adhesive film can be affected. Although research has been carried out on biobased NIPU or flame retardant adhesives, it is often difficult in the prior art to combine high bond strength, excellent environmental resistance (temperature and water resistance) with long-term stable intrinsic flame retardant properties. For example, some biobased NIPU adhesives have insufficient bond strength to match conventional high performance products, and the introduction of flame retardant components often comes at the expense of adhesion or material flexibility. Therefore, developing a hot melt adhesive film which is based on renewable resources, has green and safe synthesis process, and can integrate high bonding strength, long-acting flame retardance and good environmental resistance into a whole has become a technical problem to be solved in the art. Disclosure of Invention In order to overcome the defects in the prior art, the invention aims to provide a hot melt adhesive film with high bonding strength and a preparation method thereof. The aim of the invention is achieved by the following technical scheme: The first aspect of the present invention provides a method for preparing a hot melt adhesive film having high adhesive strength, comprising the steps of: (1) Mixing o-vanillin-based double five-membered ring carbonate and phosphorus-containing diamine, and carrying out polymerization reaction under the heating condition to obtain a prepolymer; (2) And (3) carrying out vacuum defoaming treatment on the prepolymer, then coating the prepolymer into a film, solidifying, cooling and stripping the film to obtain the hot melt adhesive film with high bonding strength. Further, the preparation process of the o-vanillin-based double five-membered ring carbonate in the step (1) is as follows: (a) Adding o-vanillin and 1, 8-octanediamine into ethanol, and carrying out reflux reaction under the action of glacial acetic acid to obtain o-vanillin bis-Schiff base diphenol; (b) Adding o-vanillin bis-Schiff base diphenol into epichlorohydrin, performing ring-opening reaction in the presence of a phase transfer catalyst, and then performing ring-closing reaction under the action of strong alkali to obtain o-vanillin bis-epoxy monomer; (c) Adding an o-vanillin-based double-oxygen monomer and a catalyst into N, N-dimethylformamide, and introducing carbon dioxide to perform cycloaddition reaction to obtain the o-vanillin-b