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CN-122011319-A - YB-B2000 polyurethane modified epoxy resin and preparation method thereof

CN122011319ACN 122011319 ACN122011319 ACN 122011319ACN-122011319-A

Abstract

The application relates to the technical field of polymer composite materials, in particular to YB-B2000 polyurethane modified epoxy resin and a preparation method thereof, wherein the YB-B2000 polyurethane modified epoxy resin comprises the steps of taking phenolic resin as a bridging unit, introducing high-density phenolic hydroxyl into bisphenol A epoxy resin under the catalysis of organic phosphine, and then reacting with-NCO end-capped polyurethane prepolymer to realize chemical grafting. The application can efficiently construct a nano-scale microphase structure, remarkably improves the toughness, heat resistance and processing stability of materials, has no heavy metal catalyst residue, and is suitable for the fields of electronic packaging, structural adhesives, composite materials and the like.

Inventors

  • LIU LI
  • ZHANG SHENGYIN
  • ZHANG SHENGJIN
  • YANG QUANQUAN

Assignees

  • 北京永邦盛达化工产品有限公司

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The preparation method of the polyurethane modified epoxy resin is characterized by comprising the following steps of: S10, reacting bisphenol A type epoxy resin with phenolic resin for 1-2 hours at 80-100 ℃ in the presence of an organic phosphine catalyst to prepare an activated epoxy intermediate; s20, reacting an oligomer polyol with excessive diisocyanate at 90-110 ℃ for 2-4 hours to prepare an-NCO end-capped polyurethane prepolymer; S30, dropwise adding the-NCO end-capped polyurethane prepolymer into the activated epoxy intermediate at the temperature of 60-70 ℃ for 2-3 hours, so that the-NCO group reacts with the phenolic hydroxyl group to form a urethane bond, and chemical grafting of a polyurethane chain is realized; s40, terminating the reaction until the viscosity of the system is 5000-8000 mPa.s, thereby obtaining the modified epoxy resin base material.
  2. 2. The method according to claim 1, wherein in the step S10, the bisphenol A type epoxy resin is selected from at least one of E-20, E-44, E-51 and Epon 828, and/or the phenolic resin has a hydroxymethyl content of 7.5 to 9.5% and a number average molecular weight of 300 to 600, and/or the mass ratio of bisphenol A type epoxy resin to phenolic resin is 100:1-20.
  3. 3. The preparation method according to claim 1 or 2, wherein in the step S20, the oligomer polyol is selected from one or more of polycaprolactone Polyol (PCL), polyethylene glycol adipate (PEA), polycarbonate diol (PCDL), hydroxyl Terminated Polybutadiene (HTPB), polytetrahydrofuran diol (PTMG), and polypropylene oxide diol (PPG), and the diisocyanate is selected from one or more of 1, 5-Naphthalene Diisocyanate (NDI), toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), p-phenylene diisocyanate (PPDI), hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (HMDI).
  4. 4. The preparation method according to claim 1, wherein in the step S10, the organic phosphine catalyst is at least one of triphenylphosphine, tributylphosphine or tri (4-methylphenyl) phosphine, and the amount of the organic phosphine catalyst is 0.1-0.5 wt% of the mass of the bisphenol a type epoxy resin.
  5. 5. The method according to claim 1 or 3, wherein in the step S20, the oligomer polyol is a polycaprolactone Polyol (PCL) having a number average molecular weight of 800 to 1200 and a hydroxyl value of 55 to 70mg KOH/g, the diisocyanate is 1, 5-Naphthalene Diisocyanate (NDI), and the molar ratio of isocyanate groups to hydroxyl groups of the 1, 5-naphthalene diisocyanate to the polycaprolactone polyol is 2:1 to 2.5:1.
  6. 6. The process according to claim 1, wherein in step S20, the resultant-NCO-terminated polyurethane prepolymer has a-NCO content of 4.0% to 5.5%.
  7. 7. The method according to claim 1, wherein in the step S30, the-NCO-terminated polyurethane prepolymer is added to the activated epoxy intermediate at a dropping rate of 0.5 to 1.5g/min, and the change in the intensity of the-NCO characteristic absorption peak at 2270cm-1 is monitored by infrared spectroscopy during the reaction, and the reaction is judged to be substantially completed when the peak intensity is reduced to 10% or less of the initial value.
  8. 8. The method according to claim 1, wherein in the step S30, a catalyst, a chain extender, a filler, a defoaming agent and/or a leveling agent is added, and/or the catalyst is at least one selected from an organotin catalyst and a tertiary amine catalyst, and/or the chain extender is at least one selected from a small molecular diol and a small molecular diamine.
  9. 9. The preparation method of claim 1, wherein the step S40 further comprises a curing step, wherein an aromatic amine curing agent is added for curing and forming, the aromatic amine curing agent is at least one of 4,4' -diaminodiphenyl sulfone, m-phenylenediamine or diaminodiphenyl methane, the dosage of the aromatic amine curing agent is 25-35% of the mass of the modified epoxy resin base material, the curing process is carried out for 2 hours before 120 ℃, and the temperature is raised to 180 ℃ for 4 hours.
  10. 10. A polyurethane modified epoxy resin characterized in that it is prepared by the preparation method of any one of claims 1 to 8, has a grafting ratio of more than 90%, and the polyurethane phase is uniformly dispersed in the epoxy matrix in nanometer scale.

Description

YB-B2000 polyurethane modified epoxy resin and preparation method thereof Technical Field The invention belongs to the technical field of polymer composite materials, and particularly relates to YB-B2000 polyurethane modified epoxy resin and a preparation method thereof. Background In the technical field of polyurethane modified epoxy resin, the prior art mostly adopts a mode of directly carrying out physical blending or chemical grafting on an-NCO-terminated polyurethane prepolymer and the epoxy resin so as to improve the toughness and the comprehensive performance of the epoxy resin. However, the conventional bisphenol a type epoxy resin has a molecular structure containing only a small amount of secondary hydroxyl groups generated by synthesis residues or hydrolysis, and has a low concentration and limited reactivity, resulting in low grafting efficiency with-NCO groups. In order to promote the grafting reaction, part of the technical proposal introduces an organotin catalyst, but the residue of the catalyst in the system can accelerate the subsequent epoxy-amine curing reaction, thereby affecting the pot life and the storage stability. In addition, if the grafting is insufficient, the polyurethane phase is easy to undergo macroscopic phase separation to form a stress concentration area, and the integral mechanical property of the material is weakened. Meanwhile, -NCO groups are sensitive to moisture in the environment, side reactions are easy to generate urea bonds and release CO 2, so that bubbles, local crosslinking and even gelation phenomena are caused, and the consistency of products and the process reproducibility are affected. The prior patent document CN115850629A (the chemical industry research institute of the academy of sciences of Guangdong) discloses a polyurethane modified epoxy resin and a preparation method thereof, wherein the epoxy resin is partially ring-opened by organic amine to improve the hydroxyl content in a system, so that the grafting efficiency with polyurethane prepolymer is improved. Although the method improves the compatibility and mechanical properties to a certain extent, the method relies on the ring-opening reaction of the organic amine on the epoxy group, the reaction condition is complex to control, the risk of byproduct generation exists, the obtained hydroxyl is still mainly secondary hydroxyl, the reactivity is relatively limited, and the upper limit exists for improving the grafting efficiency. The prior art patent document CN106414542B (japanese iron chemical) provides a polyurethane modified epoxy resin modified with a polyol (B), a polyisocyanate (c) and a low molecular weight chain extender (d) using a secondary hydroxyl group-containing bisphenol epoxy resin (a) having a specific hydroxyl group equivalent as a starting material. The scheme optimizes the selection of raw materials, but the core of the scheme is still based on the reaction of secondary hydroxyl and-NCO contained in the epoxy resin, so that the problem of insufficient hydroxyl activity is not fundamentally solved, the requirement on raw material specification is severe, and the universality and the cost control are limited. In summary, the above prior art still has room for improvement in terms of improving the chemical grafting efficiency between polyurethane and epoxy resin, inhibiting side reaction, ensuring nano-scale phase dispersion and combining high toughness and high heat resistance. Disclosure of Invention The invention provides YB-B2000 polyurethane modified epoxy resin and a preparation method thereof, and aims to construct high-density and high-reactivity phenolic hydroxyl sites on a bisphenol A epoxy resin main chain in situ by introducing phenolic resin as a bridging unit, so that an-NCO end-capped polyurethane prepolymer can be subjected to chemical grafting with the epoxy resin in a high-efficiency and directional manner, and a modified epoxy resin system with high toughness, high heat resistance, good processing stability and excellent mechanical property is obtained. Wherein YB-B2000 is the brand of polyurethane modified epoxy resin. In a first aspect, the invention provides a method for preparing polyurethane modified epoxy resin, comprising the following steps: S10, reacting bisphenol A type epoxy resin with phenolic resin for 1-2 hours at 80-100 ℃ in the presence of an organic phosphine catalyst to prepare an activated epoxy intermediate; s20, reacting an oligomer polyol with excessive diisocyanate at 90-110 ℃ for 2-4 hours to prepare an-NCO end-capped polyurethane prepolymer; S30, dropwise adding the-NCO end-capped polyurethane prepolymer into the activated epoxy intermediate at the temperature of 60-70 ℃ for 2-3 hours, so that the-NCO group reacts with the phenolic hydroxyl group to form a urethane bond, and chemical grafting of a polyurethane chain is realized; s40, terminating the reaction until the viscosity of the system is 5000-8000 mPa.s, thereby obtaining the mod