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Low-temperature deblocking isocyanate curing agent and preparation method thereof

A technology of isocyanate and curing agent, which is applied in the field of isocyanate curing agent unblocked at low temperature and its preparation, can solve the problems of affecting the bonding strength of the adhesive to wood, side effects, and easy deformation, so as to achieve easy popularization, good stability, and convenience transport effect

Active Publication Date: 2021-07-16
WUXI HUHUANG PAINT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Common blocked isocyanates need to be heated to release active –NCO groups, so the use of blocked curing agents for materials that are sensitive to temperature is limited to a certain extent
For example, the unsealing temperature of some curing agents reaches above 150°C, and the polymer material products such as paper, leather and other protein fiber products that are easily deformed and deteriorated at high temperatures are restricted.
[0004] Bisulfite is often used as a blocking agent for isocyanates because it contains active hydrogen. However, the amount of bisulfite used is more than 3 times that of isocyanate groups. Improper handling after unblocking It will also remain in the product and cause side effects (for example, when applied to adhesives, the precipitation of inorganic salts may affect the bonding strength of the adhesive to wood)

Method used

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  • Low-temperature deblocking isocyanate curing agent and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A preparation method of a low-temperature unblocked isocyanate curing agent, comprising the steps of:

[0027] Heat 80g of HDI trimer to 50°C, add 4g of sodium bisulfite to it, and react for 2h under slow stirring; further add 3g of formamidine to it, keep the temperature at 50°C for 3h; raise the temperature of the reaction system to 60°C , add 7g of triazole, heat preservation reaction for 4h, to obtain isocyanate curing agent, recorded as sample 1.

Embodiment 2

[0029] A preparation method of a low-temperature unblocked isocyanate curing agent, comprising the steps of:

[0030] Heat 90g of HDI trimer to 60°C, add 6g of potassium bisulfite to it, and react for 3h under slow stirring; further add 7g of triazine to it, keep the temperature at 60°C for 4h; raise the temperature of the reaction system to 70 ℃, add 3g of 1,2,4-triazole-3-carboxylic acid, and keep the temperature for 5 hours to obtain the isocyanate curing agent, which is recorded as sample 2.

Embodiment 3

[0032] A preparation method of a low-temperature unblocked isocyanate curing agent, comprising the steps of:

[0033] Raise the temperature of 85g HDI trimer to 55°C, add 5g of sodium bisulfite to it, and react for 2.5h under slow stirring; further add 5g of triazine to it, keep the temperature at 55°C for 3.5h; raise the temperature of the reaction system To 65°C, add 5g of triazole, keep warm for 4.5h to obtain an isocyanate curing agent, which is recorded as sample 3.

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PUM

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Abstract

The invention relates to a low-temperature deblocking isocyanate curing agent and a preparation method thereof. The preparation method comprises the following steps: (1) adding hydrosulfite into an HDI (hexamethylene diisocyanate) tripolymer under stirring, controlling the reaction temperature to be lower than 60 DEG C, then keeping the temperature, and adding an amidine compound for continuous reaction; and (2) finally, adding a triazole compound, controlling the reaction temperature to be lower than 70 DEG C, and obtaining the low-temperature deblocking isocyanate curing agent after the reaction is completed. The hydrosulfite is sodium hydrogen sulfite and potassium hydrogen sulfite; the amidine compound is one of formamidine and trinitrogen amidine; and the triazole compound is one of triazole and 1, 2, 4-triazole-3-carboxylic acid. The organic sealing agent and the inorganic sealing agent are respectively reacted with HDI (hexamethylene diisocyanate) to form a sealed isocyanate curing agent, and the prepared isocyanate curing agent can be completely deblocked at a relatively low temperature of 70-85 DEG C.

Description

technical field [0001] The invention relates to the technical field of organic chemical synthesis, in particular to a low-temperature deblocking isocyanate curing agent and a preparation method thereof. Background technique [0002] Polyurethane resins synthesized from isocyanates are widely used in wood, textile, plastic processing, automobile, construction, paint industry and other fields. Due to the interaction of the accumulated double bond and the highly electronegative nitrogen and oxygen atoms on both sides of the carbon atom, the isocyanate group has a large reactivity and can react with many compounds containing active hydrogen such as water, alcohol, amine, carboxylic acid, etc. , storage, etc. bring great inconvenience. In order to facilitate the transportation and storage of isocyanates, the stability of isocyanate groups is improved by using blocking agents to protect isocyanate groups in industry. The obtained blocked isocyanate reacts with the blocking agent...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/80
CPCC08G18/8096C08G18/8058
Inventor 施中新
Owner WUXI HUHUANG PAINT
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