External cross-linking agent for waterborne polyurethane and preparation method and application of external cross-linking agent

A technology of water-based polyurethane and external linking agent, applied in the field of coatings, can solve the problems of reducing -NCO concentration, yellowing of polyurethane color, limited hydrophilicity, etc.

Active Publication Date: 2020-11-06
QILU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Non-ionic modified polyisocyanate is generally modified by polyether (such as polyethylene glycol monoether, etc.), although this cross-linking agent has been widely recognized by the market in most application fields, but there are many Disadvantages: Due to the limited hydrophilicity brought by polyether, it is necessary to use a large amount of polyether to give polyisocyanate good water dispersion performance, which greatly reduces the -NCO concentration in the polyisocyanate system, resulting in too much NCO content in the product If the degree of cross-linking is too low, and a large number of polyether segments are introduced into the polyurethane film, it will also have a certain negative impact on the water resistance of the film.
[0006] In order to overcome the above defects, researchers have introduced hydrophilic ionic groups to achieve hydrophilic modification of isocyanate, such as hydroxyl sulfonic acid or salt, sulfamate, etc. are also used to modify isocyanate, but sulfonate will cause The noticeable yellow color of polyurethane prevents the use of these products as crosslinking components in premium coating systems

Method used

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  • External cross-linking agent for waterborne polyurethane and preparation method and application of external cross-linking agent
  • External cross-linking agent for waterborne polyurethane and preparation method and application of external cross-linking agent
  • External cross-linking agent for waterborne polyurethane and preparation method and application of external cross-linking agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Add 0.25mol of N-methylimidazole, 0.22mol of monochlorodiethylene glycol, and 50ml of acetonitrile into the three-necked flask. The reaction was carried out at 80°C under nitrogen protection for 96 hours, and the system turned into a light yellow liquid after the reaction was stopped. Wash with acetone, ethyl acetate and ether, respectively. Vacuum dry after several washes. The product was obtained, sealed and preserved (the structure is shown below):

[0053]

[0054] According to the -NCO / -OH molar ratio of 50:1, weigh the imidazolium ionic liquid modified hydroxyl-terminated polyether and HDI trimer prepared above; add the modified polyether into a clean and dry three-necked bottle, and install the stirrer And thermometer, and nitrogen protection, add HDI trimer, stir evenly, add polyether and polyisocyanate total mass 0.02% stannous octoate, heat (heating rate ≤ 5 ℃ / min), heat up to 60 ℃, keep warm 2h, then keep warm for 0.5h, cool to below 40°C, add appropr...

Embodiment 2

[0057] Add 0.25 mol of N-methylimidazole, 0.21 mol of monobrominated polyethylene glycol (M=300), and 100 ml of acetonitrile into the three-necked flask. The reaction was carried out at 80° C. under nitrogen protection for 96 hours, and the system turned into a light yellow liquid after the reaction was stopped. Wash with acetone, ethyl acetate and ether, respectively. After washing several times, vacuum-dry to obtain the product, which is sealed and stored (the structure is shown below):

[0058] (n=5)

[0059] According to the -NCO / -OH molar ratio of 20:1, weigh the imidazolium ionic liquid modified hydroxyl-terminated polyether and HDI biuret prepared above, respectively, add the modified polyether into a clean and dry three-necked bottle, and install the stirrer And thermometer, and nitrogen protection, add HDI biuret, stir evenly, add polyether and polyisocyanate total mass 0.05% stannous octoate, heat (heating rate ≤ 5°C / min), raise the temperature to 80°C, keep war...

Embodiment 3

[0062] Add 0.25 mol of N-methylimidazole, 0.2 mol of monochlorinated polyethylene glycol (M=400), and 100 ml of acetonitrile into the three-necked flask. The reaction was carried out at 80° C. under nitrogen protection for 96 hours, and the system turned into a light yellow liquid after the reaction was stopped. Wash with acetone, ethyl acetate and ether, respectively. After washing several times, vacuum-dry to obtain the product, which is sealed and stored (the structure is shown below):

[0063] (n=8)

[0064] According to the -NCO / -OH molar ratio of 60:1, weigh the imidazole ionic liquid modified hydroxyl-terminated polyether and HDI trimer prepared above, respectively, add the modified polyether into a clean and dry three-necked bottle, and install the stirrer And thermometer, and nitrogen protection, add HDI trimer, stir evenly, add polyether and polyisocyanate total mass of 0.1% dibutyltin dilaurate, heat (heating rate ≤ 5 ℃ / min), the temperature rises to 70 ℃ , k...

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Abstract

The invention relates to a preparation method of an external cross-linking agent for waterborne polyurethane. The preparation method comprises the following steps: by using imidazole ionic liquid modified hydroxyl-terminated polyether and polyisocyanate as raw materials, carrying out addition polymerization reaction under the action of a catalyst to finally obtain the external cross-linking agentfor waterborne polyurethane. The external cross-linking agent for waterborne polyurethane has nonionic and ionic hydrophilic groups and good water solubility, the water resistance, solvent resistanceand mechanical strength of a PU adhesive film can be remarkably improved, and a cross-linked coating is not sticky.

Description

technical field [0001] The invention relates to the technical field of coatings, in particular to an external linking agent for water-based polyurethane and its preparation method and application. Background technique [0002] Polyurethane (PU) has both the elasticity of rubber and the excellent processing properties of plastics. It has incomparable advantages in heat insulation, sound insulation, wear resistance, oil resistance, elasticity and other aspects. It is following polyethylene, polyvinyl chloride, The sixth largest plastic after polypropylene, polystyrene and ABS. Although traditional solvent-based polyurethane coatings have high performance, they emit volatile organic compounds (VOC) into the air during use to pollute the air and most of them will cause harm to human health. With the improvement of people's awareness of environmental protection and the increasingly stringent national environmental protection regulations, water-based polyurethane has become more ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G18/79C08G18/50C08G18/38C09D7/65C09D175/04
CPCC08G18/3848C08G18/506C08G18/792C09D175/04C09D7/65
Inventor 刘洁张斐斐李梦茹李彦春
Owner QILU UNIV OF TECH
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