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Polyurethane curing agent based on toluene diisocyanate dimer and preparation method thereof

A technology of toluene diisocyanate and toluene diisocyanate, applied in the field of curing agents, can solve the problems of high separation difficulty, waste of TDI and high separation cost, and achieve the effects of reducing the content of free monomers, saving production costs and simplifying the operation process

Inactive Publication Date: 2015-11-18
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the actual application process, it is found that in the supercritical extraction method, the extraction conditions are harsh, the separation equipment is high, and the separation is difficult.
In the solvent extraction method, the operation process is long, the energy consumption is high, the solvent is difficult to recycle, the cost is high, and the cost performance is low
It is difficult to desorb the adsorbed TDI in the molecular sieve absorption method, which leads to the inability of the molecular sieve to be recycled and the waste of a large amount of TDI, resulting in high separation costs
Thin film evaporation is currently a more commonly used separation method, which is mainly used for the separation of free monomers in TDI adduct curing agents. During the separation experiment of TDI trimers, it was found that crystallization often occurs, resulting in poor fluidity of the product or even If the pipeline is blocked, the separation of free monomers cannot be achieved effectively

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] A preparation method based on the polyurethane curing agent of toluene diisocyanate dimer, comprises the following steps:

[0044] (1) Under the protection of nitrogen, add 50g of TDI-80 into a 100ml four-neck flask equipped with a stirring paddle, the stirring speed is 80r / min, drop 3 drops (about 0.05g) of tributylphosphine with a dropper, Stop stirring after 10min, leave standstill for 1 hour, filter with 400 mesh gauze, obtain 48g of tolylene diisocyanate dimer white powder;

[0045] (2) Under nitrogen protection, add 10 g of butanol and 261 g of TDI-80 to a 1000 ml four-necked bottle equipped with a stirring paddle and a thermometer, heat up to 50° C. and keep warm for 1 hour to obtain a polyurethane prepolymer; Add the butyl acetate of 300g and the DMP-30 of 0.6g to continue to insulate for 4 hours; The toluene diisocyanate dimer powder of 29g step (1) is joined in the above-mentioned four-necked bottle, keep insulated for 2 hours again, add 0.6g benzene Formyl c...

Embodiment 2

[0049] A preparation method based on the polyurethane curing agent of toluene diisocyanate dimer, comprises the following steps:

[0050] (1) Under the protection of nitrogen, add 50g of TDI-80 into a 100ml four-neck flask equipped with a stirring paddle, the stirring speed is 90r / min, drop 5 drops (about 0.1g) of tributylphosphine with a dropper, Stop stirring after 10min, leave standstill for 1 hour, filter with 400 mesh gauze, obtain 47g of tolylene diisocyanate dimer white powder;

[0051] (2) Under the protection of nitrogen, add 12g of n-amyl alcohol and 256g of TDI-80 to a 1000ml four-necked bottle equipped with a stirring paddle (stirring speed is 100r / min) and a thermometer, heat up to 50°C and keep it warm for 1 hour, then Add 300g butyl acetate and 3gDMP-30 to the four-necked bottle and continue to insulate for 2 hours, add 32g of the toluene diisocyanate dimer powder in step (1) to the above-mentioned four-necked bottle, keep warm for another 2 hours, add 2g of ben...

Embodiment 3

[0055] A preparation method based on the polyurethane curing agent of toluene diisocyanate dimer, comprises the following steps:

[0056] (1) Under the protection of nitrogen, add 50g of TDI-80 into a 100ml four-necked bottle equipped with a stirring paddle, the stirring speed is 100r / min, drop 0.5g of triethylamine with a dropper, stop stirring after 10min, and let it stand for 1 Hour, filter with 400 order gauze, obtain the tolylene diisocyanate dimer white powder of 43g;

[0057] (2) Preparation of hydroxy-containing Mannich base: add 10g bisphenol A, 14g mass fraction of 40% formaldehyde solution and 24g Dimethylamine solution with a mass fraction of 33%, reacted at 80°C for 4 hours, allowed to stand and cool to room temperature, then separated the liquids, and distilled the oil phase under reduced pressure at 90°C and -0.95MPa to obtain Mannich base M -01;

[0058] (3) Under nitrogen protection, add 20 g of n-decyl alcohol and 245 g of TDI-80 into a 1000 ml four-necked ...

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Abstract

The invention belongs to the technical field of curing agents, and discloses a polyurethane curing agent based on a toluene diisocyanate dimer and a preparation method thereof. The preparation method comprises the steps that 1, a dimerization catalyst is added into a toluene diisocyanate monomer under the protection of nitrogen, and the mixture is stood for reaction for 1-2 h at room temperature and then filtered to obtain the toluene diisocyanate dimer; 2, hydroxyl-containing small molecular alcohol and the toluene diisocyanate monomer mixture are mixed under the protection of nitrogen and react with each other for 1-2 h at 40-60 DEG C, and a polyurethane prepolymer is obtained; polar solvent and a hydroxyl-containing trimerization catalyst are added into the polyurethane prepolymer, and heat preservation is performed at 50-60 DEG C for 2-4 h; then the toluene diisocyanate dimer is added, and heat preservation is performed at 50-60 DEG C for 2-4 h; finally, a polymerization inhibitor is added, then heat preservation is performed for 1-2 h, the temperature is lowered, materials are discharged, and the polyurethane curing agent is obtained. The preparation method is simple, and the prepared curing agent is light in color and low in viscosity and free monomer content.

Description

technical field [0001] The invention belongs to the technical field of curing agents, relates to a polyurethane curing agent with low content of free monomers, in particular to a polyurethane curing agent based on toluene diisocyanate dimer and a preparation method thereof. Background technique [0002] Toluene diisocyanate (TDI) trimer curing agent has attracted much attention because of its quick-drying properties, so the methods for preparing toluene diisocyanate trimer at home and abroad are also widely used and disclosed. Toluene diisocyanate will self-polymerize under conditions such as catalyst and heating, and form dimers, trimers, and polymers with larger molecular weights depending on the degree of reaction. [0003] There are mainly four molecular structures in toluene diisocyanate trimer, one trimer is prepared from three molecules of 2,4-toluene diisocyanate (1), and one trimer is prepared from two molecules of 2,4- 4-toluene diisocyanate and one molecule of 2,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/10C08G18/76C08G18/28
CPCC08G18/10C08G18/282C08G18/2825C08G18/7614C08G18/7657
Inventor 黄洪曹树坤司徒粤
Owner SOUTH CHINA UNIV OF TECH