News Details
Paint (paint) used crosslinking agent
2017-6-28 20:45:25
Paint (paint) used crosslinking agent
The ketone destroys the bonding of the hydrogen bonds between the polymer molecules, while the polymer can still form a hydrogen bonding effect through methanol. Three kinds of solvent toluene viscosity reducing the contribution of the lowest, this is because the toluene for strong polarity oligomer is a poor solvent, already know, for high concentration of polymer solution, good viscosity is lower than poor solvent in solvent.
Naturally, the viscosity of the solvent itself has important influence on the viscosity of the polymer solution, which can be expressed in the following formula:
Lg eta = lg eta s + W/(ka-kbw)
In the formula, W is the weight fraction in the solution, eta is the solution viscosity, eta s is the solvent viscosity, Ka and Kb are constant.
High solid color paint viscosity and related problems
The viscosity of the paint
Paint is a two-phase system, and its general expression with Mooney viscosity formula, high solid coatings with low solvent content and in the dry film of PVC under the same conditions, it will have a higher than ordinary paint in volume, such as dry film of PVC was 40%, the solid content (volume) is 70% of the coating containing the pigment volume is 70%, and the solid volume content is 35% of normal coating pigment volume is only 14%, obviously, the foreign minister (paint) with the same viscosity, high solid coatings viscosity is much larger.
The question of dispersion of pigment
In the dispersion of pigment, in order to improve the efficiency, it is hoped that the amount of resin in the dispersible medium can be smaller, as long as the amount of resin added can ensure that the dispersed pigment is not reassembled. But the amount of solvent in the high solids coatings is limited, it is not enough solvent to ensure that the dispersion medium to low resin concentration, thus dispersed in the resin solution is higher than the actual need only, so the dispersion medium viscosity is higher, the amount of each pigment dispersion will reduce, and low efficiency. On the other hand, because of the high viscosity of dispersible medium and slow wetting process, the speed of adding pigment also slows down.
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.
It is an important problem to avoid the reagglomeration flocculation in paint, which is more likely to be flocculating due to high solid content. Flocculation can cause coloring and gloss problems in general coatings, but high solids can cause a sharp increase in viscosity. The improvement of the solid content and the decrease of the molecular weight of the polymer will affect the dispersion and stability of the pigment, which must be considered in the process of painting.
Ordinary coating polymer molecular weight, in cross stitch membrane, just of the few groups to participate in the reaction, low molecular weight polymer and high solid coatings, and got behind in membrane need more groups to participate in the reaction, to achieve the desired molecular weight.
The influence of molecular weight distribution on solvent viscosity has been discussed. In fact, the molecular weight distribution not only affects the viscosity, but also is important to the distribution of functional groups.
Will cut a cut of a high molecular weight polymer, low molecular weight number in a molecule, if every small molecules on the number of functional groups on average for two, then due to the nonuniformity in points cut, will lead to the functional group distribution inhomogeneity, sometimes only a functional groups, some even can't get functional groups.
The low molecular weight polymer with functional groups or only with the greater the possibility of a functional group, and it is the need to avoid for thermosetting coating, because the molecules of plasticizer with no functional groups or "solvent", not only can affect the mechanical properties of paint film, and may cause the disadvantage of coating.
It is possible that the oligomers of "solvents" are vaporized under curing conditions and coagulated at the top of the oven. When accumulated to a certain amount, the droplet will drop, causing defects such as shrinkage of the paint film. The molecule of a single functional group is the termination agent of crosslinking reaction.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
The ketone destroys the bonding of the hydrogen bonds between the polymer molecules, while the polymer can still form a hydrogen bonding effect through methanol. Three kinds of solvent toluene viscosity reducing the contribution of the lowest, this is because the toluene for strong polarity oligomer is a poor solvent, already know, for high concentration of polymer solution, good viscosity is lower than poor solvent in solvent.
Naturally, the viscosity of the solvent itself has important influence on the viscosity of the polymer solution, which can be expressed in the following formula:
Lg eta = lg eta s + W/(ka-kbw)
In the formula, W is the weight fraction in the solution, eta is the solution viscosity, eta s is the solvent viscosity, Ka and Kb are constant.
High solid color paint viscosity and related problems
The viscosity of the paint
Paint is a two-phase system, and its general expression with Mooney viscosity formula, high solid coatings with low solvent content and in the dry film of PVC under the same conditions, it will have a higher than ordinary paint in volume, such as dry film of PVC was 40%, the solid content (volume) is 70% of the coating containing the pigment volume is 70%, and the solid volume content is 35% of normal coating pigment volume is only 14%, obviously, the foreign minister (paint) with the same viscosity, high solid coatings viscosity is much larger.
The question of dispersion of pigment
In the dispersion of pigment, in order to improve the efficiency, it is hoped that the amount of resin in the dispersible medium can be smaller, as long as the amount of resin added can ensure that the dispersed pigment is not reassembled. But the amount of solvent in the high solids coatings is limited, it is not enough solvent to ensure that the dispersion medium to low resin concentration, thus dispersed in the resin solution is higher than the actual need only, so the dispersion medium viscosity is higher, the amount of each pigment dispersion will reduce, and low efficiency. On the other hand, because of the high viscosity of dispersible medium and slow wetting process, the speed of adding pigment also slows down.
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.
It is an important problem to avoid the reagglomeration flocculation in paint, which is more likely to be flocculating due to high solid content. Flocculation can cause coloring and gloss problems in general coatings, but high solids can cause a sharp increase in viscosity. The improvement of the solid content and the decrease of the molecular weight of the polymer will affect the dispersion and stability of the pigment, which must be considered in the process of painting.
Ordinary coating polymer molecular weight, in cross stitch membrane, just of the few groups to participate in the reaction, low molecular weight polymer and high solid coatings, and got behind in membrane need more groups to participate in the reaction, to achieve the desired molecular weight.
The influence of molecular weight distribution on solvent viscosity has been discussed. In fact, the molecular weight distribution not only affects the viscosity, but also is important to the distribution of functional groups.
Will cut a cut of a high molecular weight polymer, low molecular weight number in a molecule, if every small molecules on the number of functional groups on average for two, then due to the nonuniformity in points cut, will lead to the functional group distribution inhomogeneity, sometimes only a functional groups, some even can't get functional groups.
The low molecular weight polymer with functional groups or only with the greater the possibility of a functional group, and it is the need to avoid for thermosetting coating, because the molecules of plasticizer with no functional groups or "solvent", not only can affect the mechanical properties of paint film, and may cause the disadvantage of coating.
It is possible that the oligomers of "solvents" are vaporized under curing conditions and coagulated at the top of the oven. When accumulated to a certain amount, the droplet will drop, causing defects such as shrinkage of the paint film. The molecule of a single functional group is the termination agent of crosslinking reaction.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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