Process for producing water-soluble closed isocyanic ester monomer

A technology of blocking isocyanate and isocyanate, which is applied in the field of isocyanate monomer, can solve the problems of moisture sensitivity and high reactivity, and achieve the effect of prolonging the service life, prolonging the storage period and improving the bonding effect

Inactive Publication Date: 2012-05-23
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems of high reactivity of free isocyanate groups in polyurethane adhesives and coatings and being very sensitive to moisture, the invention provides a method for preparing water-soluble blocked isocyanate monomers

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 18g sodium bisulfite is dissolved in 54g water and obtains the sodium bisulfite solution that mass fraction is 25%, and this sodium bisulfite aqueous solution mixes with 3g isopropanol to obtain blocking agent aqueous solution; 13.7g toluene diisocyanate (TDI) dissolves in A homogeneous solution with a mass fraction of TDI of 77.4% was obtained in 4 g of ethyl acetate. Under the condition of stirring at 5°C, this homogeneous solution was added dropwise to the mixture obtained by mixing sodium bisulfite aqueous solution and isopropanol according to the molar ratio of isocyanate group and blocking agent sodium bisulfite at a ratio of 1:1.1. React in the blocking agent aqueous solution for 2 hours to obtain the water-soluble blocked isocyanate monomer.

Embodiment 2

[0020] Dissolve 19g of sodium bisulfite in 50g of water to obtain a sodium bisulfite solution with a mass fraction of 27.5%. This aqueous solution of sodium bisulfite is mixed with 4g of ethanol to obtain an aqueous solution of capping agent; 19g of diphenylmethane-4,4'-bis Isocyanate (MDI) was dissolved in 4 g of butanone solvent to obtain a homogeneous solution with a mass fraction of MDI of 82.6%. Under the condition of stirring at 20°C, this homogeneous solution was added dropwise to the capping solution obtained by mixing the sodium bisulfite aqueous solution and ethanol according to the molar ratio of the isocyanate group and the capping agent sodium bisulfite as 1:1.2. Reaction in aqueous solution for 2 hours to obtain water-soluble blocked isocyanate monomer.

Embodiment 3

[0022] 20g sodium bisulfite was dissolved in 46.7g water to obtain a mass fraction of 30% sodium bisulfite solution, and this sodium bisulfite aqueous solution was mixed with 5g ethanol to obtain an aqueous blocking agent solution; 17.8g isophorone diisocyanate (IPDI) Dissolved in 5 g butanone solvent to obtain a homogeneous solution with a mass fraction of IPDI of 78.1%. Under the condition of stirring at 10°C, this homogeneous solution was added dropwise to the capping solution obtained by mixing the sodium bisulfite aqueous solution and ethanol according to the ratio of the molar ratio of the isocyanate group to the capping agent sodium bisulfite being 1:1.2. Reaction in aqueous solution for 2 hours to obtain water-soluble blocked isocyanate monomer.

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PUM

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Abstract

The invention relates to a method for preparing a water-soluble blocked isocyanate monomer, which solves the problems that free isocyanate groups in polyurethane adhesives and coatings are high in reaction activity, sensitive to moisture, and the like. The preparation method comprises the steps of blocking isocyanate groups (-NCO) by use of sodium bisulfite as an end-blocking agent under certain conditions so as to obtain a water-soluble isocyanate monomer and then preparing the water-soluble blocked isocyanate monomer by a one-step method according to that the molar ratio of NCO to HSO3<-> is between 1:1 and 1:1.3. The water-soluble blocked isocyanate monomer can be used for preparing various single-component adhesives and coatings, has the advantage of prolonging the service period and storage period of the adhesives and the coatings, and can be widely applied in the fields of coatings, adhesives, cladding materials, and so on for enameled wires, fabrics, leather, paper, wood, metal, plastics, and so on.

Description

technical field [0001] The invention relates to the fields of adhesives, coatings and the like, and more precisely relates to isocyanate monomers. Background technique [0002] Polyurethane is a synthetic material with excellent performance. It has attracted much attention for a long time. As an important raw material for the synthesis of polyurethane, the isocyanate group in the isocyanate monomer has a high reactivity with the nucleophile, making the system very active at room temperature. Cannot exist as a single component. And when used as a coating, the polyurethane coating is very sensitive to moisture in solvents, resins, pigments and other raw materials or moisture in the humid air at the construction site before curing, which adds a lot of difficulties to the application of polyurethane coatings. People desire to not only retain the excellent chemical properties of polyurethane but also improve its shortcomings in use. If the reaction of the isocyanate group to ac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C265/14C07C263/16C08G18/80C09J175/04C09D175/04
Inventor 任凤梅周正发徐卫兵王晓文
Owner HEFEI UNIV OF TECH
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