CN-121991313-A - Preparation method of polyurethane modified epoxy resin

CN121991313ACN 121991313 ACN121991313 ACN 121991313ACN-121991313-A

Abstract

The invention relates to the technical field of polymerization products, in particular to a preparation method of polyurethane modified epoxy resin, which comprises the steps of preparing polyurethane modified epoxy resin by adopting a chemical grafting method, extracting prepolymer characteristic parameters of prepared polyurethane prepolymer, predicting whether the feeding flow rate ratio of the polyurethane prepolymer to the epoxy resin needs to be regulated, judging whether the mass ratio of the polyurethane prepolymer to the epoxy resin after regulation falls within the range of the raw material ratio according to the predicted pump speed, introducing the polyurethane prepolymer and the epoxy resin into a mixer according to the predicted pump speed and the initial pump speed, extracting and calculating the compatibility index of a premix formed by the polyurethane prepolymer and the epoxy resin, and increasing the initial rotating speed of a mixing unit body according to the compatibility index or regulating the initial use amount of a catalyst by combining the prepolymer characteristic parameters. The invention avoids PU/EP phase separation by preferentially guiding the-OH reaction of the-NCO and the EP rather than side reaction to realize molecular dispersion.

Inventors

WANG LEI
FENG JING

Assignees

天津乐创新材料科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (10)

1. The preparation method of the polyurethane modified epoxy resin is characterized by comprising the following steps: Extracting prepolymer characteristic parameters of the prepared polyurethane prepolymer by adopting a chemical grafting method to prepare polyurethane modified epoxy resin, and predicting whether the feeding flow rate ratio of the polyurethane prepolymer to the epoxy resin needs to be adjusted; Judging whether the mass ratio of the polyurethane prepolymer to the epoxy resin after adjustment falls within the raw material proportioning range according to the predicted adjustment pump speed, and introducing the polyurethane prepolymer and the epoxy resin into a mixer according to the predicted adjustment pump speed and the initial pump speed; Extracting and calculating a compatibility index of a pre-mixture formed by the polyurethane prepolymer and the epoxy resin, and increasing the initial rotating speed of the mixing unit body according to the compatibility index or adjusting the initial dosage of the catalyst by combining the characteristic parameters of the prepolymer; injecting the catalyst into the outlet of the mixer for two times according to the adjusted initial dosage, and judging whether to trigger catalyst replenishing according to the temperature rising amplitude of the reaction mixture formed by adding the catalyst into the premix for the first time; In response to triggering catalyst replenishment, determining to stop replenishing catalyst and reduce reaction temperature according to the rate of viscosity rise of the reaction mixture; calculating the actual rate ratio of the split injection to the one-time injection, and quantifying the actual influence degree of the two-time catalyst addition on the reaction rate of the reaction mixture according to the actual rate ratio; Determining whether the influence degree of the catalyst batch injection on the reaction rate of the reaction mixture is within the volume adjustment range of the pipeline according to the actual rate ratio, opening a fixed switch of a movable valve in the pipeline of the reaction section or reducing the initial flow rate of the reaction mixture in the pipeline of the reaction section according to the actual rate ratio.
2. The method for preparing the polyurethane modified epoxy resin according to claim 1, wherein the process for extracting the prepolymer characteristic parameters of the prepared polyurethane prepolymer comprises the steps of: Detecting the actual dielectric constant of the polyurethane prepolymer before preliminary mixing the prepolymer and the epoxy resin by a mixer, and taking the actual dielectric constant as the characteristic parameter of the prepolymer of the polyurethane prepolymer in the current batch; And establishing a linear regression model of the content of isocyanate groups and the actual dielectric constant, and judging whether the feeding flow rate ratio of the polyurethane prepolymer to the epoxy resin needs to be adjusted according to whether the characteristic parameters of the prepolymer are in a target range.
3. The method for preparing the polyurethane modified epoxy resin according to claim 2, wherein the process of predicting and adjusting the feed flow rate ratio of the polyurethane prepolymer to the epoxy resin comprises: and when the characteristic parameters of the prepolymer are beyond or below the target range, reducing or increasing the initial pump speed of the polyurethane prepolymer into the mixer, and adjusting the feeding flow rate ratio by reducing or increasing the flow rate of the prepolymer.
4. The method for producing a polyurethane-modified epoxy resin according to claim 3, wherein the predicted initial pump speed of the adjusted polyurethane prepolymer is used as the predicted adjustment pump speed; multiplying the ratio of the predicted regulating pump speed to the initial pump speed by the initial mass ratio of the polyurethane prepolymer to the epoxy resin to obtain an actual mass ratio; And predicting whether the mass ratio of the polyurethane prepolymer to the epoxy resin after adjustment falls within the range of the raw material ratio according to the actual mass ratio.
5. The method for producing a polyurethane-modified epoxy resin according to claim 4, wherein, When the mass ratio of the polyurethane prepolymer to the epoxy resin after the prediction and adjustment exceeds or is lower than the raw material proportioning range, judging that the polyurethane prepolymer in the current batch does not meet the requirement, and stopping the preparation flow; When the mass ratio of the polyurethane prepolymer to the epoxy resin after the prediction and adjustment is in the raw material proportioning range, judging that the polyurethane prepolymer in the current batch meets the requirement, and introducing the polyurethane prepolymer and the epoxy resin into a mixer according to the prediction and adjustment pump speed and the initial pump speed.
6. The method for preparing the polyurethane modified epoxy resin according to claim 5, wherein the polyurethane prepolymer and the epoxy resin are initially mixed by a mixer and then introduced into a reaction pipeline to add a catalyst; extracting a compatibility index of a premix formed by the polyurethane prepolymer and the epoxy resin, and increasing the initial rotating speed of the mixing unit body according to a ratio of the compatibility index to the compatibility index when the compatibility index is smaller than a standard index; and when the compatibility index is greater than or equal to a standard index, adjusting the initial dosage of the catalyst according to the compatibility index and combining the characteristic parameters of the prepolymer.
7. The method for preparing a polyurethane modified epoxy resin according to claim 6, wherein after the initial amount of the catalyst is adjusted, the catalyst is injected at the outlet of the mixer in two times according to the adjusted initial amount; The pre-mixture of the polyurethane prepolymer and the epoxy resin is added with a catalyst to form a reaction mixture, the actual temperature value and the actual viscosity of the reaction mixture are detected in real time in a detection section pipeline, and the temperature rise amplitude and the viscosity rise rate are calculated; If the temperature rise amplitude is smaller than the first critical proportion of the expected value, judging that insufficient conversion needs to trigger catalyst replenishment, and verifying the result through the viscosity rise rate.
8. The method for preparing a polyurethane-modified epoxy resin according to claim 7, wherein the process of verifying the result by the viscosity increase rate comprises: if the actual viscosity rising rate is smaller than the second critical proportion of the theoretical value, determining that the conversion is insufficient and adding the catalyst; And if the viscosity rising rate is greater than a third critical proportion of the theoretical value, judging that the viscosity of the reaction mixture rises suddenly, immediately stopping adding the catalyst, and cooling to prevent gel, wherein the second critical proportion and the third critical proportion are percentages.
9. The method for producing a polyurethane-modified epoxy resin according to claim 8, wherein the actual rate ratio of the split and the one-time injection is calculated, and whether or not the degree of influence is within the pipe volume adjustment range is judged based on the actual degree of influence of the split and the one-time injection reflected on the reaction rate of the reaction mixture.
10. The method for preparing a polyurethane-modified epoxy resin according to claim 9, wherein the process of judging whether the degree of influence is within the pipe volume adjustment range comprises: When the actual rate ratio of the split injection to the one-time injection is greater than or equal to the standard rate ratio, judging that the influence degree of the batch injection of the catalyst on the reaction rate of the reaction mixture is in the volume adjusting range of the pipeline, and opening a fixed switch of a movable valve in the pipeline of the reaction section; And when the actual rate ratio of the split injection to the one-time injection is smaller than the standard rate ratio, judging that the influence degree of the batch injection of the catalyst on the reaction rate of the reaction mixture exceeds the volume adjustment range of the pipeline, and reducing the initial flow rate of the reaction mixture in the pipeline of the reaction section according to the actual rate ratio.

Description

Preparation method of polyurethane modified epoxy resin Technical Field The invention relates to the technical field of polymerization products, in particular to a preparation method of polyurethane modified epoxy resin. Background The polyurethane modified epoxy resin is a composite material combining high strength of epoxy resin and high toughness of polyurethane, and the high molecular material for modifying the epoxy resin by introducing polyurethane components aims to overcome the defects of high brittleness, poor impact resistance, insufficient wet heat resistance and the like of the epoxy resin, and simultaneously maintains excellent adhesiveness, mechanical strength and chemical stability, and obviously improves the brittleness, heat resistance and impact resistance of the epoxy resin by adjusting the PU (polyurethane)/EP ratio and the prepolymer molecular weight chemical modification performance, so that the toughness and strength can be optimized, and the thermal stability can be improved. CN117801209a discloses a polyurethane modified epoxy resin and a preparation method thereof, and the polyurethane modified epoxy resin comprises, by weight, polyether polyol, epoxy resin, isocyanate containing at least two NCO functional groups, and 0.06-0.1 part of catalyst. The preparation method comprises the steps of adding polyether polyol and isocyanate containing at least two NCO functional groups into a reaction kettle, introducing nitrogen, heating to 60-120 ℃, stirring for 2-3 hours, cooling to below 20 ℃ by cooling water, adding epoxy resin and a catalyst, stirring uniformly, heating to 100-140 ℃, and reacting for 3-6 hours to obtain the polyurethane modified epoxy resin. It can be seen that the polyurethane modified epoxy resin and the preparation method thereof have the following problems: Too high a ratio of-NCO/-OH in the control process of the grafting reaction may cause excessive crosslinking, unstable grafting rate and reduced toughness of the modified epoxy resin, and poor compatibility of polyether polyol and epoxy resin. Disclosure of Invention Therefore, the invention provides a preparation method of polyurethane modified epoxy resin, which is used for solving the problems of poor compatibility of reactants and unstable grafting rate in the control process of grafting reaction in the prior art. In order to achieve the above object, the present invention provides a method for preparing a polyurethane modified epoxy resin, comprising: Extracting prepolymer characteristic parameters of the prepared polyurethane prepolymer by adopting a chemical grafting method to prepare polyurethane modified epoxy resin, and predicting whether the feeding flow rate ratio of the polyurethane prepolymer to the epoxy resin needs to be adjusted; Judging whether the mass ratio of the polyurethane prepolymer to the epoxy resin after adjustment falls within the raw material proportioning range according to the predicted adjustment pump speed, and introducing the polyurethane prepolymer and the epoxy resin into a mixer according to the predicted adjustment pump speed and the initial pump speed; Extracting and calculating a compatibility index of a pre-mixture formed by the polyurethane prepolymer and the epoxy resin, and increasing the initial rotating speed of the mixing unit body according to the compatibility index or adjusting the initial dosage of the catalyst by combining the characteristic parameters of the prepolymer; injecting the catalyst into the outlet of the mixer for two times according to the adjusted initial dosage, and judging whether to trigger catalyst replenishing according to the temperature rising amplitude of the reaction mixture formed by adding the catalyst into the premix for the first time; Determining to trigger catalyst addition or stop catalyst addition and reduce the reaction temperature according to the viscosity rising rate of the reaction mixture; calculating the actual rate ratio of the split injection to the one-time injection, and quantifying the actual influence degree of the two-time catalyst addition on the reaction rate of the reaction mixture according to the actual rate ratio; Determining whether the influence degree of the catalyst batch injection on the reaction rate of the reaction mixture is within the volume adjustment range of the pipeline according to the actual rate ratio, opening a fixed switch of a movable valve in the pipeline of the reaction section or reducing the initial flow rate of the reaction mixture in the pipeline of the reaction section according to the actual rate ratio. Further, the process for extracting the prepolymer characteristic parameters of the prepared polyurethane prepolymer comprises the following steps: Detecting the actual dielectric constant of the polyurethane prepolymer before preliminary mixing the prepolymer and the epoxy resin by a mixer, and taking the actual dielectric constant as the characteristic parameter of the prepolymer of t