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Water friendly modification of polyurethane coating crosslinking agent
2017-6-7 11:46:25
Water friendly modification of polyurethane coating crosslinking agent
The common methods of hydrophilic modification are external emulsification and internal emulsification. Externalizing the emulsion is a direct addition of emulsifiers to the 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, the externalization method can only be applied to the materials that are not high in water resistance. 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 dispersed 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 introduction of the type of hydrophilic graph, the modification of hydrophilic modification can be divided into non-ionic modification, ion modification, non-ion and ion mixture modification.
Non-ionic modification typically involves the introduction of hydrophilic groups, such as epoxy ethane or epoxy propane, into polyisocyanates. The modified polyurethane crosslinking agent not only has a certain amount of hydrophilic, but the remaining NCO group is encased in a stable presence in the water.
Using polyethylene glycol monodimethyl ether (MPEG) and HDI trimer, wu shenghua prepared hydrophilic polyurethane crosslinking agent for the main raw materials. The results showed that the average relative molecular weight of the MPEG was 500, and the NCO group and the hydroxyl group were better than 6:1.
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 two methods: cationic and anionic modification.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
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 and others, such as cyclohexaniline propylene sulfonic acid and cyclohexaminoethyl sulfonic acid, were modified to make water-loving polyurethane crosslinking agent. The results show that the modified polyurethane crosslinking agent does not need the high shear force to be distributed evenly in the water and has good storage stability. The new type of amino sulfonic acid and HDI tripolymerization were used to modify polyurethane crosslinking agent.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
The common methods of hydrophilic modification are external emulsification and internal emulsification. Externalizing the emulsion is a direct addition of emulsifiers to the 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, the externalization method can only be applied to the materials that are not high in water resistance. 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 dispersed 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 introduction of the type of hydrophilic graph, the modification of hydrophilic modification can be divided into non-ionic modification, ion modification, non-ion and ion mixture modification.
Non-ionic modification typically involves the introduction of hydrophilic groups, such as epoxy ethane or epoxy propane, into polyisocyanates. The modified polyurethane crosslinking agent not only has a certain amount of hydrophilic, but the remaining NCO group is encased in a stable presence in the water.
Using polyethylene glycol monodimethyl ether (MPEG) and HDI trimer, wu shenghua prepared hydrophilic polyurethane crosslinking agent for the main raw materials. The results showed that the average relative molecular weight of the MPEG was 500, and the NCO group and the hydroxyl group were better than 6:1.
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 two methods: cationic and anionic modification.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
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 and others, such as cyclohexaniline propylene sulfonic acid and cyclohexaminoethyl sulfonic acid, were modified to make water-loving polyurethane crosslinking agent. The results show that the modified polyurethane crosslinking agent does not need the high shear force to be distributed evenly in the water and has good storage stability. The new type of amino sulfonic acid and HDI tripolymerization were used to modify polyurethane crosslinking agent.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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