CN-122011996-A - Bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive and preparation method and application thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive, a preparation method and application thereof, wherein a bio-based epoxy monomer is prepared by using a bio-based raw material containing phenolic hydroxyl groups and epoxy chloropropane through an epoxidation reaction, and then the bio-based epoxy monomer and dicarboxymethyl propionic acid are introduced into a crosslinking site through a ring-opening esterification reaction of carboxyl groups and epoxy groups to obtain a multi-functional group-containing bio-based crosslinking agent; the bio-based cross-linking agent participates in cross-linking reaction in a polyurethane system, so that the density of a network structure is improved, and an aromatic conjugated framework endows a material with intrinsic ultraviolet absorption capacity, so that the integration of ultraviolet resistance and cross-linking function is realized, and the traditional petroleum-based additive type auxiliary agent is effectively replaced; meanwhile, the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive obtained by utilizing the reaction of the bio-based crosslinking agent and the polyurethane prepolymer has excellent weather resistance, bonding stability and environmental friendliness, and is suitable for high-reliability bonding scenes such as aerospace and the like.

Inventors

• LIAO DONG
• RAO QIUSHI
• LI JIAN

Assignees

• 深圳市航信科技有限公司

Dates

Publication Date

20260512

Application Date

20260224

Claims (10)

1. 1. The preparation method of the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive is characterized by comprising the following steps: Mixing a bio-based raw material containing phenolic hydroxyl, epichlorohydrin and a first catalyst, and obtaining a bio-based epoxy monomer through a first reaction; Mixing the bio-based epoxy monomer, dimethylolpropionic acid and a second catalyst, and performing a second reaction to obtain a bio-based crosslinking agent; Mixing polyester polyol or polyether polyol with diisocyanate, and obtaining polyurethane prepolymer with terminal isocyanate groups through a third reaction; And mixing the bio-based crosslinking agent with the polyurethane prepolymer, and performing coating and curing treatment to obtain the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive.
2. 2. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the bio-based raw material containing phenolic hydroxyl groups is selected from one or more of eugenol, 4-vinylphenol, cardanol, vanillyl alcohol, demethylated lignin and monobutyric acid.
3. 3. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the mass ratio of the bio-based raw material containing phenolic hydroxyl groups, the epichlorohydrin and the first catalyst is 1 (0.2-1) (0.01-0.2).
4. 4. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the temperature of the first reaction is 50 ℃ to 80 ℃, and the time of the first reaction is 2h to 5h.
5. 5. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the temperature of the second reaction is 90 ℃ to 120 ℃, and the time of the second reaction is 3h to 6h.
6. 6. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the first catalyst is one or more selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and organic tertiary amine; and/or the second catalyst is selected from one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, triethylamine, dibutyltin dilaurate and tetrabutyl titanate.
7. 7. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the mass ratio of the bio-based epoxy monomer to the dimethylol propionic acid to the second catalyst is 1 (0.1-1): 0.01-0.1.
8. 8. The method for preparing the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive according to claim 1, wherein the mass fraction of the bio-based crosslinking agent in the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive is 0.5% -15%.
9. 9. A bio-based uv-resistant polyurethane pressure-sensitive adhesive, characterized in that it is prepared by the preparation method of the bio-based uv-resistant polyurethane pressure-sensitive adhesive as claimed in any one of claims 1 to 8.
10. 10. Use of the bio-based uv-resistant polyurethane pressure-sensitive adhesive according to claim 9 in aircraft skin sealants, floor and composite interlayer adhesives, wire harness cladding adhesives or sensor fixing adhesives.

Description

Bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive and preparation method and application thereof Technical Field The invention relates to the technical field of adhesives, in particular to a bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive and a preparation method and application thereof. Background In the aerospace field, the pressure-sensitive adhesive is used for key parts such as structural bonding, sealing and the like, and needs to withstand severe environments such as strong ultraviolet rays, high-low temperature changes and the like for a long time. However, the traditional polyurethane pressure-sensitive adhesive is easy to age by ultraviolet light, the tensile strength is reduced by up to 38.6 percent after the ultraviolet light aging, the tearing strength is reduced by about 7 percent, and simultaneously, the color is deepened, the surface is cracked, roughened and micro-cracked and holes appear, and the structure containing benzene rings is extremely easy to oxidize under ultraviolet light to generate quinone chromophores, so that serious yellowing is caused. Therefore, conventional polyurethane pressure-sensitive adhesives are susceptible to uv light aging, leading to yellowing, embrittlement and adhesive failure. However, the existing anti-ultraviolet method depends on additive type auxiliary agents such as ultraviolet absorbers or nano oxides, but has the problems of uneven migration, precipitation and dispersion, and the like, so that long-acting stable protection is difficult to realize. For example, a small-molecule ultraviolet absorber can migrate from the inside of a glue layer to the surface during storage or use to form white mist or powdery precipitates, which seriously affect transparency and appearance, and an auxiliary agent migrating to the glue layer can migrate to the surface of a glued substrate, so that the substrate is polluted or the optical surface is atomized, and the ultraviolet absorber cannot be applied to applications such as an electronic protective film, an optical adhesive tape and the like. At present, the anti-ultraviolet auxiliary agent used by the polyurethane pressure-sensitive adhesive is mainly from petroleum-based systems, such as organic ultraviolet absorbers of benzotriazoles, benzophenones and the like, is not renewable, and part of the auxiliary agent has toxicity or light instability and is easy to volatilize or degrade in long-term service, so that the protective effect is affected. Accordingly, the prior art is still in need of improvement and development. Disclosure of Invention In view of the defects of the prior art, the invention aims to provide a bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive and a preparation method and application thereof, and aims to solve the problems of yellowing, embrittlement and bonding failure caused by easy ultraviolet aging of the existing ultraviolet-resistant polyurethane pressure-sensitive adhesive. The technical scheme of the invention is as follows: In a first aspect, the invention provides a method for preparing a bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive, which comprises the following steps: Mixing a bio-based raw material containing phenolic hydroxyl, epichlorohydrin and a first catalyst, and obtaining a bio-based epoxy monomer through a first reaction; Mixing the bio-based epoxy monomer, dimethylolpropionic acid and a second catalyst, and performing a second reaction to obtain a bio-based crosslinking agent; Mixing polyester polyol or polyether polyol with diisocyanate, and obtaining polyurethane prepolymer with terminal isocyanate groups through a third reaction; And mixing the bio-based crosslinking agent with the polyurethane prepolymer, and performing coating and curing treatment to obtain the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive. Preferably, the preparation method of the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive comprises the step of preparing a bio-based raw material containing phenolic hydroxyl groups, wherein the bio-based raw material containing phenolic hydroxyl groups is selected from one or more of eugenol, 4-vinyl phenol, cardanol, vanillyl alcohol, demethylated lignin and monobutyric acid. Preferably, the preparation method of the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive comprises the steps of (1) (0.2-1) (0.01-0.2) of the bio-based raw material containing phenolic hydroxyl groups, the epichlorohydrin and the first catalyst. Preferably, the preparation method of the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive comprises the steps of enabling the temperature of the first reaction to be 50-80 ℃ and enabling the time of the first reaction to be 2-5 h. Preferably, the preparation method of the bio-based ultraviolet-resistant polyurethane pressure-sensitive adhesive comprise