News Details
Different coating crosslinking agent effect
2017-6-3 15:41:56
Different coating crosslinking agent effect
The effect of the addition of epoxy resin on the performance of PUA emulsion. Increase as the adding amount of epoxy resin, modified waterborne polyurethane emulsion appearance changed from clear to micro, viscosity, emulsion storage stability, film hardness increases obviously, low temperature flexibility, adhesion, water resistance and alcohol resistance significantly better.
This is because the epoxy resin for the high degree of polyol, in the reaction with polyurethane can be branched points into the main chain of the PUA, to form a network structure, the formation water dispersion system, in the PU epoxy resin molecular chain will exist in the latex particle surface, when the water to evaporate and latex particles through mutual squeezing osmotic membrane formation, exists in the epoxy resin molecules decreases surface hydrophilic membrane hydrophilic, improve the water resistance of the waterborne polyurethane.
The addition of epoxy resin increases the amount of crosslinking structures in the molecule, and the better the water resistance. On the other hand, the amount of epoxy resin is increased, the stiffness is increased, the hardness is increased, the low temperature flexibility is poor. Epoxy resin has excellent adhesion on various substrate, so as the amount of epoxy resin increases, the adhesion increases.
But the adding amount of epoxy resin is not the more the better, the introduction of extra epoxy resin can improve the average reaction system functionality, from polymer system viscosity increases rapidly, reaction process stability, but also reduces the hydrophilic polyurethane resin, polyurethane emulsion appearance and storage stability. Therefore, suitable epoxy resin is added for 4.0% ~ 6.0%.
The effect of castor oil addition on PUA emulsion performance. As castor oil content increased, the appearance of the composite emulsion by clear change to micro, emulsion viscosity, storage stability, film of low temperature flexibility, water resistance and alcohol resistance and dirt resistance is good, hardness, adhesion declined slightly.
When alone with polyether, emulsion appearance clear, but the water resistance of the film and feel less film containing castor oil, castor oil is three fatty acid glyceride and its molecular polarity fatty acid chains make film has good hydrophobic, softness and bending resistance.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
Because of castor oil for small molecule crosslinking agent, containing long hydrophobic fatty acid side chain, with the increase of castor oil, film crosslinking degree increase, enhanced hydrophobic, thus coating enhanced resistance to water. When the castor oil is more than 9%, the membrane performance of the aqueous polyurethane emulsion is poor. Accordingly, the appropriate castor oil content should be controlled by 5% ~ 7%.
TMP content on the properties of PUA emulsion influence can be seen, with the increase of TMP additives, coating hardness, resistance to water, alcohol and fouling resistance are improved, especially the resistance to water and alcohol resistance, ink polluting has improved significantly. Compared with castor oil, TMP is more remarkable for the improvement of the coating water and the resistance of the medium.
This is because the TMP are of small molecular weight, faculties degrees of polyols, can provide for the amount of small high crosslinking density, at the same time as the TMP content increase, increasing average functionality of system, molecular entanglement between the close degree of increase, volume smaller, PU prepolymer gradually by the molecular structure of the linear development to have crosslinking structure.
This kind of crosslinking structure increases the density of the membrane, and obviously the hardness, water resistance, mellow and anti-fouling properties of the coating are also improved. As the amount of TMP increased to more than 5 per cent, the emulsion was made from transparent to more transparent and increased viscosity.
Visible TMP can make excessive emulsion appearance and storage stability, and after joining the TMP of excessive causes a pre polymer viscosity increases obviously, difficult to emulsion in water, lead to the PU dispersion particle coarsening, PUA condensation polymerization process, storage is not stable.
TMP, moreover, a great influence on the emulsion of the minimum film-forming temperature and increase with the adding quantity TMP, emulsion of the minimum film-forming temperature is higher and higher, so that cannot under the interesting film. The flexibility of the coating at low temperature increases with the addition of TMP. Combined, the appropriate TMP addition is 2% ~ 3%.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
The effect of the addition of epoxy resin on the performance of PUA emulsion. Increase as the adding amount of epoxy resin, modified waterborne polyurethane emulsion appearance changed from clear to micro, viscosity, emulsion storage stability, film hardness increases obviously, low temperature flexibility, adhesion, water resistance and alcohol resistance significantly better.
This is because the epoxy resin for the high degree of polyol, in the reaction with polyurethane can be branched points into the main chain of the PUA, to form a network structure, the formation water dispersion system, in the PU epoxy resin molecular chain will exist in the latex particle surface, when the water to evaporate and latex particles through mutual squeezing osmotic membrane formation, exists in the epoxy resin molecules decreases surface hydrophilic membrane hydrophilic, improve the water resistance of the waterborne polyurethane.
The addition of epoxy resin increases the amount of crosslinking structures in the molecule, and the better the water resistance. On the other hand, the amount of epoxy resin is increased, the stiffness is increased, the hardness is increased, the low temperature flexibility is poor. Epoxy resin has excellent adhesion on various substrate, so as the amount of epoxy resin increases, the adhesion increases.
But the adding amount of epoxy resin is not the more the better, the introduction of extra epoxy resin can improve the average reaction system functionality, from polymer system viscosity increases rapidly, reaction process stability, but also reduces the hydrophilic polyurethane resin, polyurethane emulsion appearance and storage stability. Therefore, suitable epoxy resin is added for 4.0% ~ 6.0%.
The effect of castor oil addition on PUA emulsion performance. As castor oil content increased, the appearance of the composite emulsion by clear change to micro, emulsion viscosity, storage stability, film of low temperature flexibility, water resistance and alcohol resistance and dirt resistance is good, hardness, adhesion declined slightly.
When alone with polyether, emulsion appearance clear, but the water resistance of the film and feel less film containing castor oil, castor oil is three fatty acid glyceride and its molecular polarity fatty acid chains make film has good hydrophobic, softness and bending resistance.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
Because of castor oil for small molecule crosslinking agent, containing long hydrophobic fatty acid side chain, with the increase of castor oil, film crosslinking degree increase, enhanced hydrophobic, thus coating enhanced resistance to water. When the castor oil is more than 9%, the membrane performance of the aqueous polyurethane emulsion is poor. Accordingly, the appropriate castor oil content should be controlled by 5% ~ 7%.
TMP content on the properties of PUA emulsion influence can be seen, with the increase of TMP additives, coating hardness, resistance to water, alcohol and fouling resistance are improved, especially the resistance to water and alcohol resistance, ink polluting has improved significantly. Compared with castor oil, TMP is more remarkable for the improvement of the coating water and the resistance of the medium.
This is because the TMP are of small molecular weight, faculties degrees of polyols, can provide for the amount of small high crosslinking density, at the same time as the TMP content increase, increasing average functionality of system, molecular entanglement between the close degree of increase, volume smaller, PU prepolymer gradually by the molecular structure of the linear development to have crosslinking structure.
This kind of crosslinking structure increases the density of the membrane, and obviously the hardness, water resistance, mellow and anti-fouling properties of the coating are also improved. As the amount of TMP increased to more than 5 per cent, the emulsion was made from transparent to more transparent and increased viscosity.
Visible TMP can make excessive emulsion appearance and storage stability, and after joining the TMP of excessive causes a pre polymer viscosity increases obviously, difficult to emulsion in water, lead to the PU dispersion particle coarsening, PUA condensation polymerization process, storage is not stable.
TMP, moreover, a great influence on the emulsion of the minimum film-forming temperature and increase with the adding quantity TMP, emulsion of the minimum film-forming temperature is higher and higher, so that cannot under the interesting film. The flexibility of the coating at low temperature increases with the addition of TMP. Combined, the appropriate TMP addition is 2% ~ 3%.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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