High-crosslinking-density water dispersible nonionic isocyanate curing agent and preparation method thereof

A technology of isocyanate and polyisocyanate, which is applied in the field of water-dispersed non-ionic isocyanate curing agent and its preparation, can solve the problems of difficult dispersion, decreased gloss of coating film, and decreased NCO functionality, and achieve excellent water resistance and chemical resistance. Preparation The effect of simple process and high cross-linking density

Inactive Publication Date: 2019-06-18
英德市国彩精细化工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Patents US3996154, US4433095, and US5563207 use polyethylene glycol monoether as a hydrophilic component to modify polyisocyanate. Although this polyether modified curing agent has been widely recognized by the market in most application fields, it also exists Some disadvantages: Since polyethylene glycol monoether is a non-ionic hydrophilic modifier containing only one hydroxyl group, the NCO functionality will decrease after reacting with isocyanate groups, and the crosslinking density of the paint film obtained when used as a curing agent is not high enough , affecting water resistance and chemical resistance
Moreover, when the molecular weight of polyethylene glycol monoether is small, a stable dispersion is often not obtained after water dispersion; when the molecular weight is large, the obtained modified polyisocyanate has strong crystallinity and poor water dispersibility
[0004] Zhang Dongyang et al. (Development and application of water-dispersible polyisocyanate, Coating Industry 2018, 38 (11), 37-40.) used polypropylene glycol with a molecular weight of 1000 and polyethylene glycol monomethyl ether with a molecular weight of 600 as the hydrophilic The water modifier is combined with the modified polyisocyanate, and it is found that when the ratio of polypropylene glycol to polyethylene glycol monomethyl ether is high, the modified polyisocyanate with high cross-linking density can be obtained, and it has good hand-stirring dispersibility. However, due to the poor hydrophilicity of the polypropylene glycol structure, the obtained aqueous dispersion has a large white particle size, and the coating film is prone to disadvantages such as gloss reduction.
[0005] Sun Xiaohong and others (Master's Thesis: Preparation and Performance Research of Waterborne Polyurethane Curing Agent) synthesized a series of high-functionality water-dispersed isocyanate curing agents using polyethylene glycol and trimer polyisocyanate as raw materials, but the use of polyisocyanate Ethylene glycol has a regular structure and strong crystallinity, and the obtained hydrophilic modified polyisocyanate has high viscosity and is not easy to disperse in water

Method used

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  • High-crosslinking-density water dispersible nonionic isocyanate curing agent and preparation method thereof
  • High-crosslinking-density water dispersible nonionic isocyanate curing agent and preparation method thereof
  • High-crosslinking-density water dispersible nonionic isocyanate curing agent and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0028] Put into the reactor Desmodur N 3300 (Covestro solvent-free HDI trimer, NCO content is 21.8 ± 0.3%) 830.0 parts by mass, Ymer N120 (a diol with a polyether segment in the side arm with a molecular weight of 1000, Perstorp) 170.0 parts by mass, and 0.5 parts by mass of dibutyltin dilaurate. After the addition, the temperature was raised to 65-75° C., kept under nitrogen atmosphere and continued to stir until the NCO value reached the theoretical value. After cooling to room temperature, the obtained 100% solid-containing hydrophilic modified polyisocyanate is a near colorless transparent viscous liquid with a measured NCO value of 16.7% and a viscosity (25° C.) of 6900 cps. The reaction schematic diagram of the preparation method of the present invention is shown in figure 1 .

Embodiment 2

[0030] 840.0 parts by mass of Desmodur Z 4470MPA / X (Covestro IPDI trimer, 70% solid content, NCO content of 11.9 ± 0.3%), Ymer N120 (the side wall with a molecular weight of 1000 has a polyether segment Dibasic alcohol, Perstorp) 160.0 parts by mass, 245.0 parts by mass of propylene glycol methyl ether acetate, 0.5 parts by mass of bismuth isooctanoate, after the addition, the temperature is raised to 65-75 ° C, and the temperature is kept under nitrogen atmosphere and the reaction is continued until NCO value reaches the theoretical value. After cooling to room temperature, the obtained 60% solid-containing hydrophilic modified polyisocyanate was a nearly colorless transparent viscous liquid with a measured NCO value of 7.0% and a viscosity (25° C.) of 1200 cps.

Embodiment 3

[0032] Synthesis of hydrophilic modifier X: 90.0 parts by mass of YmerN120 (a diol with a polyether segment in the side arm with a molecular weight of 1000, Perstorp) and 45.0 parts by mass of ε-caprolactone, 0.2 mass part of stannous octoate Put a portion into a reaction kettle, protect it with nitrogen, heat to 130°C, react for 24 hours, and cool to room temperature to obtain a waxy white solid X with a theoretical molecular weight of 1500.

[0033] Put 830.0 parts by mass of Desmodur N 3300 (Covestro solvent-free HDI trimer, NCO content is 21.8 ± 0.3%) in the reactor, 255.0 parts by mass of the above-mentioned synthesized hydrophilic modifier X (theoretical molecular weight is 1500), 0.5 parts by mass of dibutyltin dilaurate, after the addition, the temperature is raised to 65-75° C., kept under nitrogen atmosphere and kept stirring until the NCO value reaches the theoretical value. After cooling to room temperature, the obtained 100% solid-containing hydrophilic modified p...

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Abstract

The invention belongs to the technical field of flocculating agents, and discloses a high-crosslinking-density water dispersible nonionic isocyanate curing agent and a preparation method thereof. According to the method, by weight, 70-99 parts of aliphatic polyisocyanate A, 1-30 parts of glycol B with polyether side arms and 0.001-0.5 part of catalysts C are subjected to heating reaction to obtainthe water dispersible nonionic isocyanate curing agent. The molecular structure of the glycol B with the polyether side arms is as shown in the specification, R1 and R5 are same or different monovalent, unsubstituted or substituted alkyls, R2, R3 and R4 are same or different bivalent, unsubstituted or substituted alkyls, and / or the alkyls are spaced by O, S, N or P, and n>5. Hydrophilic polyetherchain segments of the water dispersible nonionic isocyanate curing agent are positioned on the side arms of molecules and easily dispersed in water, and can be cured with hydroxy waterborne resin toobtain a coating with high crosslinking density and excellent water and chemical resistance.

Description

technical field [0001] The invention belongs to the technical field of flocculants, in particular to a water-dispersed nonionic isocyanate curing agent with high crosslink density and a preparation method thereof. Background technique [0002] Due to the pressure of environmental protection, the use of solvent-based coatings is restricted due to serious environmental and health problems. The development of environmentally friendly water-based coatings is the current development trend of the coatings industry. Especially the water-based two-component polyurethane coating composed of hydroxyl-containing water-based resin and water-based isocyanate curing agent, because it can be cured at room temperature, has low VOC, high gloss, good water resistance, solvent resistance and weather resistance, and its comprehensive performance is close to or reached. Solvent-based two-component polyurethane coatings have received widespread attention at home and abroad, and research and devel...

Claims

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Application Information

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IPC IPC(8): C08G18/48C09D175/08
Inventor 龙志云
Owner 英德市国彩精细化工有限公司
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