Method for Determination of Low Free Toluene Diisocyanate Content in Polyurethane Prepolymers

A technology of toluene diisocyanate and polyurethane prepolymer, which is applied in measurement devices, material separation, instruments, etc., can solve the problems of inaccurate low-concentration detection, low detection sensitivity, low resolution, etc., and can solve the problems of chromatographic peak tailing, High sensitivity and good repeatability

Active Publication Date: 2019-06-25
SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method needs to be derived, which is cumbersome, and the intermediate process will introduce errors; the other is to use (4.Von Uwe Lotz fared+lackHeft.Quantitative Bestimmung monomerer Isocyanate85:172-75) high performance liquid chromatography normal phase silica gel column for direct detection , but there are problems such as low resolution, low detection sensitivity, and inaccurate low concentration detection

Method used

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  • Method for Determination of Low Free Toluene Diisocyanate Content in Polyurethane Prepolymers
  • Method for Determination of Low Free Toluene Diisocyanate Content in Polyurethane Prepolymers
  • Method for Determination of Low Free Toluene Diisocyanate Content in Polyurethane Prepolymers

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Experimental program
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Effect test

Embodiment 1

[0039] (1) Instrument

[0040] High performance liquid chromatography (waters company) including breeze 1525 pump, 2487 dual-wavelength ultraviolet detector, Nova-Pak SiO 2 Chromatographic column (3.9x150mm, id 604μm, waters company), the analysis software is empower;

[0041] (2) Reagents

[0042] The standard sample TDI was purchased from Bayer, Germany; the mobile phase 2,2,4-trimethylpentane and 1,4-dioxane were high-performance liquid chromatography grade reagents, purchased from Merck, Germany;

[0043] (3) Determination of standard curve

[0044] Accurately weigh 0.0980g of TDI standard reagent into a 100ml volumetric flask, add the initial mobile phase to dissolve, and configure it as a standard solution stock solution. Then take 0.5ml, 1ml, 1.5ml, 2ml, 3ml, 5ml of the above-mentioned stock solution and dissolve them into a 50ml volumetric flask with the initial mobile phase to configure the standard series, and take 10 μl of each standard series solution and use a ...

Embodiment 2

[0048] Accurately weigh 4.7148g sample LF800A (Chemtura, free TDI≤0.1wt%) and dissolve it in mobile phase to a 50ml volumetric flask to obtain the test solution. Adopt high performance liquid chromatograph gradient elution, ultraviolet detection wavelength 237nm, obtain chromatogram see image 3 , it can be seen that the peaks of the TDI components can achieve baseline separation, quantified by the peak area external standard method, and the concentrations measured twice in a row are 28.32ug / ml and 28.26ug / ml, and the free TDI monomer is calculated in the prepolymerization The content in the body is 0.030%. All the other are with embodiment 1.

Embodiment 3

[0050] Accurately weigh 1.0215g sample LF950A (Chemtura, free TDI≤0.1wt%) and dissolve it in mobile phase to a 50ml volumetric flask to obtain the test solution. The liquid to be tested is injected into a liquid chromatograph for gradient elution, and the ultraviolet detection wavelength is 220nm. The peaks of the TDI components can be separated from the baseline, and quantified by the peak area external standard method, and the content of the free TDI monomer in the prepolymer is 0.043 %. All the other are with embodiment 1.

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Abstract

The invention discloses a method for measuring the content of low free toluene diisocynate (TDI) in polyurethane prepolymer. A high performance liquid chromatographic instrument is adopted; the detection wavelength is 220 nm to 237 nm; by the adoption of a gradient elution mode, direct dissolving measurement is realized, and a peak area external standard method is used for quantification. The method disclosed by the invention is easy to operate, high in sensitivity, high in separation degree and wide in detection range, and can accurately measure low-concentration free TDI.

Description

technical field [0001] The invention belongs to a method for determining the content of toluene diisocyanate, in particular to a method for determining the content of low free toluene diisocyanate (TDI) in polyurethane prepolymers by high performance liquid chromatography. technical background [0002] There is unreacted toluene diisocyanate (free TDI) in the polyurethane prepolymer of the TDI system, which has a strong pungent smell and is harmful to the human body after inhalation. In today's world with increasingly stringent requirements for environmental protection, the content of free monomers in prepolymers must be controlled below 0.5%, and some have reached below 0.1%, which makes it necessary to analyze and detect TDI content in trace amounts . [0003] At present, there are three methods for detecting the content of free TDI: chemical method, gas chromatography and high performance liquid chromatography, but each method has some problems. [0004] The chemical me...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N30/02G01N30/06
CPCG01N30/02G01N30/06G01N2030/027
Inventor 黄冬梅李源张园力乔岩樊卫斌
Owner SHANXI INST OF COAL CHEM CHINESE ACAD OF SCI
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