CN-121991623-A - High-strength ultraviolet/moisture dual-curing PUR hot melt adhesive and preparation method and use method thereof

Abstract

The invention discloses a high-strength ultraviolet/moisture dual-curing PUR hot melt adhesive and a preparation method and a use method thereof. The adhesive comprises, by weight, 60-75 parts of isocyanate-terminated polyurethane prepolymer, 10-20 parts of polyurethane acrylate, 10-30 parts of reactive diluent, 1-5 parts of photoinitiator, 0.1-0.5 part of filler, 0.5-2 parts of silane coupling agent and 5-20 parts of tackifying resin. The polyurethane acrylate is prepared by reacting the isocyanate-terminated polyurethane prepolymer with an acrylate monomer, and the adhesive has the dual advantages of quick ultraviolet curing, quick positioning, high-strength and durability of moisture curing, good process adaptability, ultrahigh bonding strength, excellent heat resistance and ageing resistance, and is particularly suitable for quick assembly line bonding and assembly of precision components such as electronic components, optical components and the like.

Inventors

• CHENG JIANGUANG
• SUI XUEBIN
• ZHANG XIAOYU
• CHEN DENGYU
• WANG ZIPING
• HE CHANGSHENG

Assignees

• 南通高盟新材料有限公司

Dates

Publication Date

20260508

Application Date

20260326

Claims (10)

1. 1. The high-strength ultraviolet/moisture dual-curing PUR hot melt adhesive is characterized by comprising the following components in parts by weight: 60-75 parts of isocyanate-terminated polyurethane prepolymer, 10-20 Parts of polyurethane acrylic ester, 10-30 Parts of a reactive diluent, 1-5 Parts of a photoinitiator, 0.1 To 0.5 part of filler, 0.5-2 Parts of silane coupling agent, 5-20 Parts of tackifying resin.
2. 2. The high-strength ultraviolet/moisture dual-curing PUR hot melt adhesive of claim 1, wherein the isocyanate-terminated polyurethane prepolymer is prepared by reacting dihydric alcohol with isocyanate in the presence of auxiliary polyphosphoric acid and a catalyst, wherein the molar ratio of isocyanate groups to hydroxyl groups is (1.5-2.5) to 1.
3. 3. The high strength uv/moisture dual cure PUR hot melt adhesive of claim 2, wherein the glycol is a mixture of one or more of polyether glycol, polyester glycol, polycarbonate glycol; The isocyanate is one or a mixture of more of hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, toluene diisocyanate and diphenyl methyl diisocyanate; The catalyst is one or a mixture of a plurality of organic bismuth catalysts.
4. 4. The high strength uv/moisture dual cure PUR hot melt adhesive of claim 3, wherein the polyether glycol includes, but is not limited to, one or more of polyethylene oxide glycol having an average molecular weight of 2000-4000, polypropylene glycol having an average molecular weight of 2000-6000, or polytetrahydrofuran having an average molecular weight of 2000-4000; The polyester diol comprises aromatic polyester polyol and aliphatic polyester polyol with average molecular weight of 1000-4000; The polycarbonate diol includes, but is not limited to, polycarbonate diol (PCDL) having an average molecular weight of 2000-4000.
5. 5. The high strength uv/moisture dual cure PUR hot melt adhesive of claim 1, wherein the urethane acrylate is prepared from a terminal isocyanate based urethane prepolymer reacted with an acrylate monomer.
6. 6. The high strength uv/moisture dual cure PUR hot melt adhesive of claim 5, wherein the acrylate monomer is a hydroxyl containing acrylate monomer or a combination of hydroxyl containing acrylate monomers and non-hydroxyl containing acrylates.
7. 7. The high-strength ultraviolet/moisture dual-cure PUR hot melt adhesive of claim 6, wherein the hydroxyl-containing acrylate monomer is one or two of hydroxypropyl acrylate and hydroxyethyl acrylate, and the hydroxyl-free acrylate monomer is one or more of trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and ethoxylated trimethylolpropane triacrylate.
8. 8. The high strength uv/moisture dual cure PUR hot melt adhesive of claim 6, wherein the photoinitiator is a free radical photoinitiator; The reactive diluent is a monofunctional (meth) acrylate; The filler is one or a mixture of more of hydrophobic fumed silica, calcium carbonate, silicon micropowder, hydrophobic precipitation method silica, quartz powder and bentonite; The tackifying resin comprises one or more of petroleum resin, hydrogenated petroleum resin, terpene resin, phenolic resin, rosin, hydrogenated rosin.
9. 9. The method for preparing a high-strength ultraviolet/moisture dual-curing PUR hot-melt adhesive according to any one of claims 1 to 8, comprising the steps of: S1, synthesizing an isocyanate-terminated polyurethane prepolymer, namely heating one or more of polyether glycol, polyester glycol and polycarbonate glycol to 100-120 ℃, stirring under vacuum condition, dewatering for 2-3 hours, removing trace moisture, cooling the dewatered glycol or glycol mixture to 50-80 ℃, adding auxiliary polyphosphoric acid, stirring for 10-30 minutes, adding metered isocyanate and catalyst, stirring under vacuum condition, reacting, and monitoring that the NCO group content reaches a theoretical value of 1.7-4.5%, thus obtaining the isocyanate-terminated polyurethane prepolymer; S2, synthesizing polyurethane acrylic ester, namely taking the measured isocyanate-terminated polyurethane prepolymer prepared in the step S1, adding an acrylic ester monomer, and reacting at 70-80 ℃ under the condition that the vacuum degree is lower than 100Pa to obtain the polyurethane acrylic ester; And S3, preparing a dual-curing system, namely taking the isocyanate-terminated polyurethane prepolymer in the step S1 and the polyurethane acrylic ester in the step S2 according to a formula under the light-shielding condition, sequentially adding tackifying resin, a photoinitiator, an active diluent, a silane coupling agent and a filler into the polyurethane prepolymer, and fully stirring and dispersing the mixture uniformly to obtain the ultraviolet/moisture dual-curing PUR hot melt adhesive.
10. 10. The method of using a high strength uv/moisture dual cure PUR hot melt adhesive of any one of claims 1 to 8, comprising the steps of: (I) Sizing, namely utilizing an automatic glue dispenser to be matched with a needle cylinder, and dispensing the adhesive on the surface of the first substrate along a preset path; (II) ultraviolet light primary curing, namely irradiating by using a UV-LED light source with the wavelength of 365nm or 395nm, controlling the energy to be 500-1000 mJ/cm < 2 >, and completing the primary photo-curing of the adhesive in 3-10 seconds; (III) aligning and pressing the second base material on the surface of the adhesive after finishing the primary photo-curing, precisely controlling the height difference and the laminating pressure between the two base materials by a laminating machine, finishing final assembly, and laminating the base materials to be bonded; (IV) placing the part attached in the step (III) at room temperature until the part is completely cured.

Description

High-strength ultraviolet/moisture dual-curing PUR hot melt adhesive and preparation method and use method thereof Technical Field The invention relates to the technical field of high polymer adhesives, in particular to an ultraviolet/moisture dual-curing reaction type polyurethane hot melt adhesive, and especially relates to a multifunctional high-performance PUR hot melt adhesive with the characteristics of rapid positioning of hot melt sizing, rapid construction of ultraviolet curing and final curing enhancement of moisture curing. Background Along with continuous improvement of industrial automation level, higher requirements are put forward on process suitability, bonding strength and weather-proof stability of adhesives for assembly of high-speed production lines, complex special-shaped structures and precise parts, and the traditional single-curing adhesive is difficult to meet the bonding requirements of modern industry, and the specific technical bottlenecks are as follows: the traditional thermoplastic hot melt adhesive has the characteristics of high production efficiency and simple process by virtue of the advantages of quick positioning by melt sizing and cooling, but the adhesive has no cross-linking solidification structure, belongs to thermoplastic materials, has the defects of poor heat resistance, weak chemical medium corrosion resistance, easy creep failure at high temperature and the like, is only suitable for non-stressed common bonding scenes, and cannot meet the requirements of strength and durability of structural bonding. The single-component moisture-curable Polyurethane (PUR) hot melt adhesive is formed by introducing an isocyanate group moisture crosslinking system based on the traditional hot melt adhesive, and a three-dimensional thermosetting network structure is formed after curing, so that the adhesive strength, heat resistance, ageing resistance and dielectric resistance of the adhesive layer are greatly improved, and the single-component moisture-curable Polyurethane (PUR) hot melt adhesive becomes a main stream option in the field of structural bonding. The adhesive has two major technical bottlenecks, which restrict the application of the adhesive in high-speed production lines and complex structures, namely firstly, the opening time and the initial curing speed are difficult to be compatible, the initial strength is built slowly while the opening time is prolonged and can be matched with the complex structures, the production line beat and the assembly efficiency are directly affected, secondly, the adhesive is completely dependent on the moisture diffusion in the air to realize the curing, and the problems of incomplete curing, poor bonding strength and the like are extremely easy to occur in the shadow area, deep gaps, sealed cavities and other parts of the structures. To overcome the above problems, the development of ultraviolet/moisture dual cure adhesives is being advanced in the industry, trying to combine the dual advantages of ultraviolet cure rapid prototyping and moisture cure depth enhancement. However, the existing dual-curing adhesive is mostly a liquid system, lacks the special instant high initial viscosity of the hot melt adhesive, has poor filling suitability on the uneven surface of the substrate, has insufficient stability in a high-temperature melting state, cannot be compatible with a hot melt sizing process, and is difficult to meet the dual requirements of process convenience and high bonding performance. Therefore, the double-curing PUR hot-melt adhesive with the advantages of fusion hot-melt sizing manufacturability, ultraviolet rapid curing sizing property and moisture final curing high performance is developed to meet the requirements of high-speed assembly and structural bonding in the field of precision manufacturing, and has urgent industry requirements and important industrial values. Disclosure of Invention In order to overcome the technical defects and shortcomings of the existing dual-curing adhesive and the traditional PUR hot melt adhesive, the invention aims to provide the high-strength ultraviolet/moisture dual-curing PUR hot melt adhesive, which can quickly construct initial bonding strength through ultraviolet irradiation after melt sizing to realize instant positioning and fixing of workpieces, continuous irradiation is not needed later, residual isocyanate groups in an adhesive layer can finish deep crosslinking curing by depending on environmental moisture, and finally, an adhesive layer with ultrahigh bonding strength, excellent heat resistance and ageing resistance is formed. The invention is realized by the following technical scheme: In a first aspect, the invention provides a high-strength ultraviolet/moisture dual-curing PUR hot melt adhesive, which comprises the following components in parts by weight: 60-75 parts of isocyanate-terminated polyurethane prepolymer, 10-20 Parts of polyurethane acrylic ester, 10-30 Parts of