High-solid and averaged-molecular weight non-toxic polyurethane curing agent for sub-gloss varnish and preparation method thereof

A polyurethane curing agent, the technology of average molecular weight, applied in the direction of coating, can solve problems such as poor fluidity, achieve the effect of good fluidity, reduce usage, and reduce product viscosity

Inactive Publication Date: 2015-10-28
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitations of technical conditions and other aspects, during the process of thin film evaporation and separation of free monomers of toluene diisocyanate trimer alone, the sample molecules will crystallize, agglomerate, etc., and the fluidity is poor, and the thin film evaporation separation cannot be completed well.

Method used

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  • High-solid and averaged-molecular weight non-toxic polyurethane curing agent for sub-gloss varnish and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] A preparation method for a non-toxic polyurethane curing agent with a high solid-containing average molecular weight for matt paint, comprising the following steps:

[0038](1) Under the protection of nitrogen, add 100kg of toluene diisocyanate (TDI-80) and 50kg of ethyl acetate into the reactor A, turn on the stirring (the stirring speed is 300r / min), raise the temperature to 55°C, and then Add 0.15kg of DMP-30 catalyst dropwise (the dropping rate is 50 drops / min) into reactor A, measure the NCO value every 1 hour until the NCO drops to 19%, cool down to 40°C, add 0.45kg of phosphoric acid to inhibit polymerization agent, stirred evenly to obtain toluene diisocyanate.

[0039] (2) Under the protection of nitrogen, mix 100kg of trimethylolpropane and 0.1kg of BF-5, and add it dropwise to reactor B containing 600kg of toluene diisocyanate (TDI-80) at 60°C. Stir rapidly (the rotating speed of stirring is 600r / min), keep warm and react for 4h after the dropwise addition i...

Embodiment 2

[0045] A preparation method for a non-toxic polyurethane curing agent with a high solid-containing average molecular weight for matt paint, comprising the following steps:

[0046] (1) Under the protection of nitrogen, add 100kg of toluene diisocyanate (TDI-80) and 80kg of ethyl acetate into the reactor A, turn on the stirring (the stirring speed is 300r / min), raise the temperature to 55°C, and then Add 0.36kg DMP-30 and 0.18kg tri-n-propylamine mixed catalyst dropwise (dropping speed is 50 drops / min) into reactor A, measure NCO value every 1 hour until NCO drops to 17%, and cool down to 40°C And add 0.5kg phosphoric acid polymerization inhibitor, stir and retain;

[0047] (2) Under the protection of nitrogen, after mixing 120kg trimethylolpropane and 0.12kg BF-5, add dropwise at 60°C (50 drops / min) to 700kg toluene diisocyanate (TDI-80 ) in the reaction kettle B, stir rapidly during the dropwise addition (stirring speed is 600r / min), after the dropwise addition is completed,...

Embodiment 3

[0053] A preparation method for a non-toxic polyurethane curing agent with a high solid-containing average molecular weight for matt paint, comprising the following steps:

[0054] (1) Under the protection of nitrogen, add 100kg of toluene diisocyanate (TDI-80) and 25kg of ethyl acetate into the reactor A, turn on the stirring (the stirring speed is 300r / min), raise the temperature to 55°C, and then Add 0.0416kg DMP-30 and 0.0208kg triethylamine mixed catalyst (dropping speed is 45 drops / min) in reactor A, measure the NCO value every 1 hour, until NCO drops to 23%, cool down to 40 ℃ and Add 0.4kg phosphoric acid polymerization inhibitor, stir and retain;

[0055] (2) Under the protection of nitrogen, after mixing 140kg trimethylolpropane and 0.14kg BF-5, add it dropwise at 60°C (50 drops / min) to the tank containing 650kg toluene diisocyanate (TDI) In reaction kettle B, stir rapidly during the dropwise addition (stirring speed is 600r / min), keep warm for 4 hours after the drop...

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Abstract

The invention belongs to the technical field of curing agents and discloses a high-solid and averaged-molecular weight non-toxic polyurethane curing agent for a sub-gloss varnish and a preparation method thereof. The method comprises the steps of (1) in the nitrogen protection environment, adding a catalyst drop by drop in a reaction vessel filled with a solvent and toluene diisocynate during the stirring process, reacting at the temperature of 40-55 DEG C, cooling on the condition that the content of NCO is lowered to be 13%-23%, and adding an acidic polymerization inhibitor to obtain a toluene diisocyanate trimer; (2) mixing a polyhydroxy compound with a dehydrating agent, adding the obtained mixture in the toluene diisocyanate drop by drop, reacting and cooling to obtain a polyurethane addition product; (3) stirring and mixing the toluene diisocyanate trimer with the polyurethane addition product, separating in a film evaporator, adding a dilution solvent and stirring evenly to obtain the high-solid and averaged-molecular weight non-toxic polyurethane curing agent. The curing agent is centralized in the distribution of molecular weight, low in viscosity, and high in content of effective isocyanate groups. After a varnish is prepared by the curing agent, a paint film is fast in drying speed, good in levelability and high in fullness.

Description

technical field [0001] The invention belongs to the technical field of curing agents, and relates to a polyurethane curing agent, in particular to a non-toxic polyurethane curing agent with high solid content and average molecular weight for matte paint and a preparation method thereof. Background technique [0002] Polyurethane coatings have excellent performance and have always been one of the most important varieties of coatings. Among them, two-component polyurethane coatings are the most widely used. One component of two-component coatings is a hydroxyl resin, and the other is a resin containing Isocyanate-based curing agent. Methods for preparing isocyanate group-containing polyurethane curing agents using aliphatic and aromatic diisocyanates have been widely disclosed and applied. [0003] Under the action of a catalyst, toluene diisocyanate (TDI) will self-polymerize into a self-polymer mixture (mostly called a trimer) with a six-membered ring structure of isocyanur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09D7/12C08G18/79C08G18/78C08G18/02C08G18/32
Inventor 黄洪曹树坤司徒粤殷代武谭卉文徐绍君
Owner SOUTH CHINA UNIV OF TECH
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