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Preparation method and application of low-activity MDI-50 product

A MDI-50, low-activity technology, applied in adhesive types, polyurea/polyurethane adhesives, organic chemistry, etc., can solve the problems affecting the production process of laminating adhesive, high activity, low impurity content, etc.

Pending Publication Date: 2020-12-29
WANHUA CHEMICAL (NINGBO) CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the purity of MDI-50 produced by this method is too high and the activity is too large, which affects the production process of the laminating adhesive.
[0004] Chinese patent CN109180531A provides a method to obtain MDI-50 products with extended shelf life, which reduces the overall activity of MDI-50 by utilizing the reactivity of the NCO at the 2-position is lower than that of the NCO at the 4-position
At present, the purity of the product under this process is high, the content of impurities is low, and the free chlorine is about 1-2ppm, and the activity is relatively high during the use in the field of laminating adhesives.

Method used

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  • Preparation method and application of low-activity MDI-50 product

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036]The crude MDI that will contain 60wt% bicyclic, 10wt% tricyclic, 10wt% tetracyclic, 20wt% pentacyclic and mixtures of five or more rings is introduced into the vacuum separation tower at a bottom temperature of 215°C and a tower top temperature of 90°C. Separation under the process condition of tower top pressure 0.4kpa, obtain diphenylmethane diisocyanate mixture A1 and polymeric MDI, the 2,2-MDI that will obtain from the separation tower, the 2,4-MDI of 10wt%, The diphenylmethane diisocyanate mixture A1 of 88wt% 4,4-MDI is introduced into the rectification tower, and various parameters are adjusted through the tower temperature, extraction ratio, etc., wherein the temperature of the rectification tower bottom is controlled at 210 ° C, and the online 4 , the temperature of the 4-MDI extraction section is 208°C, and the online 4,4-MDI extraction ratio is based on the weight of the isocyanate mixture fed to the rectification tower to control the mass ratio at 80%, to obtai...

Embodiment 2

[0038] The crude MDI that will contain 63wt% bicyclic, 12wt% tricyclic, 8wt% tetracyclic, 17wt% pentacyclic and more than five rings is introduced into the vacuum separation column at a bottom temperature of 215°C and a tower top temperature of 90°C. Separation under the process condition of tower top pressure 0.4kpa, obtain diphenylmethane diisocyanate mixture A2 and polymerized MDI, the 2,2-MDI that will obtain from separation tower, the 2,4-MDI of 11wt% The diphenylmethane diisocyanate mixture A2 of 86.7wt% 4,4-MDI is introduced into the rectification tower, and various parameters are adjusted by tower temperature, recovery ratio, etc., wherein the temperature of the rectification tower bottom is controlled at 209°C, The temperature of the online 4,4-MDI extraction section is 207.8°C, the online 4,4-MDI extraction ratio is based on the weight of the isocyanate mixture fed to the rectification tower to control the mass ratio at 78%, and 2,2-diphenylmethane is obtained The di...

Embodiment 3

[0040] The crude MDI that will contain 60wt% of two rings, 10wt% of three rings, 10wt% of four rings, 20wt% of five rings and mixtures above five rings is introduced into the vacuum separation tower at a temperature of 213°C at the bottom of the tower, and a temperature of 89°C at the top of the tower. Separation under the process condition of tower top pressure 0.4kpa, obtain diphenylmethane diisocyanate mixture A3 and polymerized MDI, the 2,2-MDI that will obtain from the separation tower, the 2,4-MDI that contains 10.3wt% MDI, the diphenylmethane diisocyanate mixture A3 of 87.2wt% 4,4-MDI is introduced into the rectification tower, and various parameters are adjusted by tower temperature, extraction ratio, etc., wherein the temperature of the rectification tower bottom is controlled at 208°C , the temperature of the online 4,4-MDI extraction section is 207°C, the mass ratio of the online 4,4-MDI extraction is 78%, and the weight of the isocyanate mixture fed to the rectifica...

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Abstract

The invention relates to a preparation method and application of a low-activity MDI-50 product; the preparation method comprises the steps: controlling the proportion of 2,4-diphenylmethane diisocyanate and 4,4-diphenylmethane diisocyanate isomers and the content of free chlorine in an online diphenylmethane diisocyanate mixture in a rectifying tower, and enriching the free chlorine through a crystallization process; and then adding a diphenyl methane diisocyanate mixture with low impurity content and high content of 2,4-diphenyl methane diisocyanate for blending to obtain the MDI-50 product with free chlorine content of 5-20 ppm. The MDI-50 product is applied to the field of laminating adhesives, thereby being beneficial to stable control of viscosity in the application process in the field of laminating adhesives.

Description

technical field [0001] The invention relates to a preparation method and application of a low activity MDI-50 product. Background technique [0002] Polyurethane laminating adhesive is mainly used in flexible packaging such as food, medicine, detergent, etc. It has the characteristics of softness, transparency, and strong adhesion. Through flexible formula design and raw material selection, special properties such as oil resistance, acid resistance, and high temperature resistance can be obtained. , has high research value and practical value. One of the main raw materials of polyurethane laminating adhesive is MDI-50. The activity of MDI-50 will affect the viscosity change rate during the production process of the laminating adhesive. For example, if the activity of MDI-50 is too high, it will lead to a large amount of trimer in the process, resulting in too high viscosity and making the laminating adhesive unqualified. Even lead to equipment blockage. [0003] Chinese p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C263/20C07C265/14C08G18/76C09J175/04
CPCC07C263/20C08G18/7671C09J175/04C07C265/14
Inventor 陆洋王会会王文博张宏科李翀
Owner WANHUA CHEMICAL (NINGBO) CO LTD
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