Water-based blocked isocyanate curing agent and preparation method thereof, water-based coating

A technology for blocking isocyanate and water-based coatings, applied in the field of coatings, can solve the problems of no obvious improvement in the thickness of the coating film, increase the production cost, and the thickness of the coating film. simple craftsmanship

Active Publication Date: 2021-11-30
湖南湘江关西涂料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, VOCs (Volatile Organic Compounds) emissions in solvent-based coatings are harmful to the human body and the environment. With the enhancement of environmental awareness and the establishment of environmental regulations, traditional solvent-based coatings have been gradually eliminated due to excessive VOCs content and thick coatings.
In recent years, most of the new coating systems are designed around how to reduce VOCs, but the thickness of the coating film has not been significantly improved
For example, water-based polyurethane intermediate paint, although it solves the problem that the automotive intermediate paint is mainly solvent-based, achieves the use of water as a solvent, and obviously reduces environmental pollution, but the water-based polyurethane intermediate paint must meet the corresponding requirements. Stone chip resistance, the thickness of the coating film must be increased, usually the thickness of the coating film needs to reach more than 80 μm, which greatly increases the production cost

Method used

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  • Water-based blocked isocyanate curing agent and preparation method thereof, water-based coating
  • Water-based blocked isocyanate curing agent and preparation method thereof, water-based coating
  • Water-based blocked isocyanate curing agent and preparation method thereof, water-based coating

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preparation example Construction

[0064] Another embodiment of the present invention is to provide a method for preparing the above-mentioned water-based blocked isocyanate curing agent, which includes the following steps S1-S4.

[0065] S1. Hydrophilic modification and chain extension of polyethylene glycol monomethyl ether, polyether diol and polyisocyanate to obtain a urethane prepolymer.

[0066] In one embodiment, before the steps of hydrophilic modification and chain extension, the step of dehydrating polyethylene glycol monomethyl ether and polyether diol is also included, and the polyethylene glycol monomethyl ether is controlled to And the water content of the polyether diol is less than 0.1 wt%.

[0067] Further, the dehydration conditions include: the degree of vacuum is less than or equal to -0.099MPa, the temperature is 80°C-105°C, and the time is 0.5h-4h.

[0068] Preferably, the degree of vacuum is -0.1MPa˜-0.099MPa.

[0069] In one embodiment, the temperature for hydrophilic modification and ...

Embodiment 1

[0098] (1) Polyethylene glycol monomethyl ether (MPEG1000) and polyethylene glycol (PEG1000) are placed in a four-necked round bottom flask, and toluene is added (the amount of toluene is 10% of the weight of polyethylene glycol monomethyl ether) , insert a thermometer, then turn on the oil pump, remove water under reduced pressure (vacuum degree is -0.099MPa, temperature is 80°C, time is 4h), the water content of the end point control mixture is 0.07%, and cooled to 40°C.

[0099] (2) Install a reflux condenser, a thermocouple, a thermometer, and a nitrogen tube on the above-mentioned four-necked round-bottomed flask, and in a stirring state, add ethyl acetate (the consumption of ethyl acetate is 10% to 20% of the total volume of the reaction system) ), HDI trimer polyisocyanate, blowing in nitrogen at the same time, dispersing for 15min, then raising the temperature to 90°C, stopping blowing in nitrogen, and reacting for 2h to obtain a urethane prepolymer.

[0100] (3) Alkal...

Embodiment 2

[0104] (1) Place polyethylene glycol monomethyl ether (MPEG300) and polyethylene glycol (PEG500) in a four-necked round-bottomed flask, add toluene (the amount is 10wt% of polyethylene glycol monomethyl ether), insert a thermometer , then turn on the oil pump, remove water under reduced pressure (vacuum degree is -0.099MPa, temperature is 99°C, time is 2h), the water content of the mixture is controlled at the end point to be 0.1%, and cooled to 40°C.

[0105] (2) Install a reflux condenser, a thermocouple, a thermometer, and a nitrogen pipe on the above-mentioned four-necked round-bottomed flask, add ethyl acetate and IPDI trimer polyisocyanate under stirring, blow into nitrogen simultaneously, disperse for 15min, and then Raise the temperature to 90°C, stop blowing nitrogen, and react for 2 hours to obtain a urethane prepolymer.

[0106] (3) Alkali metal salts of alcohols (potassium tert-butoxide) and malonate blocking agent (dimethyl malonate) were pre-dispersed at room tem...

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Abstract

The invention relates to a water-based blocked isocyanate curing agent, a preparation method thereof, and a water-based paint. The water-based blocked isocyanate curing agent includes the following raw materials: polyisocyanate trimer, polyethylene glycol monomethyl ether, polyether glycol, blocking agent, cosolvent, alkali metal alkoxide and neutralizing agent; wherein, the The polyisocyanate is selected from at least one of aliphatic polyisocyanate trimer and aromatic polyisocyanate trimer, and the polyethylene glycol monomethyl ether is selected from polyethylene glycol ether monohydric alcohols with a molecular weight of 300-2000 The molecular weight of the polyether diol is 120-1000. The water-based blocked isocyanate curing agent can react with resins with active groups such as amino resins and polyester resins in coating formulations, and introduce a large number of flexible segment structures into the coating film, which can delay the energy release of the coating film when it is hit by stones , and then improve the anti-stone chip performance of the coating film, so that the coating film has stone chip resistance under the condition of low film thickness.

Description

technical field [0001] The invention relates to the technical field of coatings, in particular to a water-based blocked isocyanate curing agent, a preparation method thereof, and a water-based coating. Background technique [0002] With the advancement of science and technology and the high speed of transportation, automobiles are becoming more and more popular, and the speed of automobiles is also greatly increased. This brings great convenience to people, but also puts forward higher requirements for the surface coating of automobiles. As an important outdoor means of transportation, the car body's surface coating may be hit by heavy objects such as falling materials and road gravel during actual driving, which will cause the coating to peel off. Therefore, it is necessary to improve the stone impact resistance of automobile coatings to reduce the damage to automobile coatings caused by heavy objects such as road gravel, so as to protect automobiles. [0003] At present, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G18/79C08G18/48C08G18/28C08G18/80C09D175/04
CPCC08G18/283C08G18/4825C08G18/792C08G18/794C08G18/80C09D175/04
Inventor 喻佳杨鹏飞张杰胡启明黄鹂
Owner 湖南湘江关西涂料有限公司
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