The hydrophilic modification of polyurethane coating crosslinking agent

The hydrophilic modification of polyurethane coating crosslinking agent, hydrophilic modification methods have external emulsification method and internal emulsification method. External emulsification method is directly adding emulsifier which, by physical mixing. External emulsification method exists particle size difference is big, poor compatibility, emulsifier film easy to drift into membrane surfaces, makes the film surface is hydrophilic, water resistance of coating is reduced.

Therefore, external emulsification method can only be applied to the preparation of materials of resistance to water demand is not high. Internal emulsification method is introduced in direct in polyurethane pre polymers containing hydrophilic group or hydrophilic group modification of chain extension agent, after the preparation of the crosslinking agent is mixed with water, hydrophilic group in the molecule toward the water, not only can protect the NCO group, and hydrophilic group repel each other can make more isocyanate stable dispersion in water; Cross stitch film, film forming matter does not exist in the free of hydrophilic small molecules, the external emulsification method in water resistance, solvent resistance and physical and mechanical properties are improved significantly.

According to the types of introducing hydrophilic group chart, hydrophilic modification can be mainly divided into non-ionic modification, ion concentration, non-ionic and ionic blending modification.

Non-ionic modification is generally will contain hydrophilic groups such as ethylene oxide or propylene oxide introduced the isocyanate. Of the modified polyurethane crosslinking agent not only has certain hydrophilicity, and the rest of the NCO group was wrapped, enable it to the existence of the stable in water.

Sheng-hua wu, polyethylene glycol monomethyl ether (MPEG) and HDI trimer as the main raw material was prepared by hydrophilic polyurethane crosslinking agent. The test results show that the hydrophilic monomer MPEG average relative molecular mass is 500, molar ratio of NCO group and hydroxyl 6:1, the preparation of waterborne polyurethane crosslinking agent performance is good.

Lai, IPDI and trimethylolpropane (TMP) reaction, MPEG as the hydrophilic chain, the preparation of waterborne polyurethane crosslinker, the crosslinking agent significantly improved the structure and properties of waterborne polyurethane.

Ion modification can be divided into cationic modification and anionic modified two methods.




Chinese name: Diethyl toluene diamine(DETDA)

Chinese alias: aryl, aryl diethyl - aryl - methyl-p-phenylenediamine

English name: Benzenediamine, ar, ar-diethyl-ar-methyl-English aliases:Diethyltoluenediamine; ar, ar-Diethyl-ar-methylbenzenediamine;Diethylmethylbenzenediamine;

CAS No. :68479-98-1

EINECS No. :270 -877-4

Molecular formula: C11H18N2

Molecular Weight: 178.28

Boiling point: 310 ℃

Refractive index: 1.581

Flash Point: > 140 ℃

Inchi: InChI = 1/C11H18N2/c1-4-8-6-7 (3) 10 (12) 11 (13) 9 (8) 5-2/h6H ,4-5,12-13H2 ,1-3H3 density : 1.022

Risk Codes: R10; R35

RIDADR: UN 3082

Safety instructions: S2; S26; S39; S61

Packing Group: III

Hazard Class: 6.1


Cationic modification is to contain cationic substance (such as pyridine, imidazole Weng salt Weng salt and quaternary ammonium salt, etc.) introduced the isocyanate, reacts with the acid and salt, can get a more hydrophilic isocyanate. ShenXiangHui with 2, 4 - such as TDI and polyethylene glycol (PEG) 1000 as the main raw material, N - methyl diethanolamine (MDEA) bind to hydrophilic chain extender, acetanilide as the blocking agent, with the synthesized by emulsion hydrophilic modification of polyurethane crosslinking agent.

Containing hydroxyl resin synthesis of cationic groups is more complex, you can use the product is less, and cationic modified synthetic steps required, the cost is high, the existence of cationic NCO group and lively hydrogen reaction, reduces the stability of the system, application of little value, so seldom use.

Anionic modified polyurethane crosslinker pH less than 7, can delay the response speed of NCO group and water, to extend the using time, so this method more commonly used than cationic modification. Carboxylic acid, sulfonic acid salt, phosphate salt is a common anionic modified material, by introducing containing carboxyl and sulfonic group anion groups, adding neutralizing agent (such as triethylamine, N - methyl piperidine or N - methyl pyrrole, etc.) for neutralization, was able to stable dispersion in water polyurethane crosslinking agent.

Laas to hexanaphthene amino propionic acid and cyclohexanol taurine as modifier, made of hydrophilic polyurethane crosslinking agent. Results show that the sulfonic acid modified polyurethane crosslinking agent does not require high shear force can be evenly dispersed in water and has good storage stability. JiXueShun adopts new type of amino sulfonic acid and HDI trimer reaction modified polyurethane crosslinking agent.

The results showed that in the N, N - dimethyl cyclohexylamine and molar ratio of amino sulfonic acid is 1.05, temperature is 100 ℃, reaction time was 4 h, amino sulfonic acid dosage was 2.5% ~ 3.0% under the condition of preparation of high performance, easy dispersion can be water-based polyurethane crosslinking agent.

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Diethyl toluene diamine(DETDA)  http://www.yaruichem.com