News Details
PU coating crosslinking agent
2017-5-11 17:54:35
PU coating crosslinking agent. PU synthetic temperature is too high, in the pre polymers not only color is darker, and may produce some branched and cross-linked, the branched and cross-linked PU produced in coarser particles dispersed in water, even the gel. The temperature is too low, and the prepolymer is long enough to make a predetermined amount of N C %.
For TDI system suitable reaction temperature (75 ~ 80 ℃), and with IPDI synthesis, IPDI some low activity, temperature should be controlled in (85 ~ 90 ℃). In the synthesis of PUA phase polymerization of acrylates optimum temperature (75 ~ 95 ℃), lower initial temperature, increasing temperature, the late for acrylate monomer reaction completely. The acrylate monomer reaction is not fully received by the PUA dispersion and there is a clear single body odor.
The effects of TMP. The addition of TMP led to the introduction of interconnection points in the PU prepolymer stage. Obviously, the excess of TMP will make polyurethane gel. After joining TMP also can make the PU dispersion in water even if you don't gel particle coarsening, after the water dispersion PUA coarse particles of the preparation of PU, viscosity, dispersion and a half has milk-white, lack of transparency, filter residue, storage is not stable.
The particles are too big, and it is possible to make PUA gel. Define gamma = TMP hydroxy/polyester glycol + TMP hydroxyl. The experiment found that only the PUA dispersion, which was stable at gamma < 0.25, was established. Gamma > 0.25, although it can be made into a well-formed PU dispersion, the particles become coarser and even gels when further polyacrylate nucleate structure PUA.
HEMA serves as a bridge between polyacrylate and polyurethane shells. PU prepolymer is a large molecular emulsifier, which is separated by water, and the acrylate monomer is surrounded by emulsification and solidified into a hard core. H E M A has A significant effect on the performance of the coating, with the increase of the HEMA, the hardness and brittleness of the coating.
Because H E M A is single hydroxyl compounds, and the reaction of polyurethane prepolymer sealing side effect, not excessive use, otherwise will make the macromolecule emulsifier was closed at both ends. This kind of large molecules more double bonds in the subsequent polymerization have the effect of crosslinking agent, excessive cross-linking led to the decrease of the PUA dispersion particle coarsening, transparency, and storage stability, may also be synthetic gel.
When HEMA is used, the bridge between pa-pu is poor and the film is water-resistant. HEMA amounts to 2.5% ~ 4.0% of the solid total.
DEGDA causes the formation of local crosslinks in polyacrylates, and excessive cross-linking makes the coating brittle. Because of the crosslinking reaction occurred in the process of polymerization of vinyl monomer, so DEGDA can't dosage is too large, according to the amount of acrylic ester, DEGDA dosage is 0.7% ~ 1.5%.
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
Methyl methacrylate (GMA) can improve the water resistance of the coating and increase the resistance to ethanol and acetone. The dosage of the coating is obviously decreased, so it is reasonable to control its dosage, which can be increased to 2% ~ 10% of acrylate.
DAAM and ADH are used in conjunction with a normal weight ratio of about 2:1 or so [4], and DAAM is 8 to 10 percent of acrylate. DAAM is added before the polyacrylate polymerization, because it is soluble in water, and it can be mixed with a small amount of water before it is mixed with the urethane water. ADH in PUA cooled to 50 ℃ below add after polymerization, ADH soluble in water, directly add stir more than 0.5 h can be dissolved completely.
Multiple cross-linked PUA performance. The construction performance and drying performance are the same as that of regular PUA dispersion. The coating was not whitened by 24h, and the anti-ethanol wiper was up to two times, and the resistance of acetone was three times higher.
Multiple cross-linking PUA dispersion base performance. Various crosslinking methods set at an organic whole, adjust the proportion of each component, to the reasonable coordination, and avoid excessive crosslinking, preparation of the PUA some multiple crosslinking, thus proving the feasibility of the method. The dispersion is stable, and the amount of hard and hard monomer can be coated with different hardness.
Coating with good resistance to water, water is not white, ethanol and acetone cleaning resistance than ordinary PUA dispersion coatings have obviously improved and can be used in the manufacture of waterborne wood coatings.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
For TDI system suitable reaction temperature (75 ~ 80 ℃), and with IPDI synthesis, IPDI some low activity, temperature should be controlled in (85 ~ 90 ℃). In the synthesis of PUA phase polymerization of acrylates optimum temperature (75 ~ 95 ℃), lower initial temperature, increasing temperature, the late for acrylate monomer reaction completely. The acrylate monomer reaction is not fully received by the PUA dispersion and there is a clear single body odor.
The effects of TMP. The addition of TMP led to the introduction of interconnection points in the PU prepolymer stage. Obviously, the excess of TMP will make polyurethane gel. After joining TMP also can make the PU dispersion in water even if you don't gel particle coarsening, after the water dispersion PUA coarse particles of the preparation of PU, viscosity, dispersion and a half has milk-white, lack of transparency, filter residue, storage is not stable.
The particles are too big, and it is possible to make PUA gel. Define gamma = TMP hydroxy/polyester glycol + TMP hydroxyl. The experiment found that only the PUA dispersion, which was stable at gamma < 0.25, was established. Gamma > 0.25, although it can be made into a well-formed PU dispersion, the particles become coarser and even gels when further polyacrylate nucleate structure PUA.
HEMA serves as a bridge between polyacrylate and polyurethane shells. PU prepolymer is a large molecular emulsifier, which is separated by water, and the acrylate monomer is surrounded by emulsification and solidified into a hard core. H E M A has A significant effect on the performance of the coating, with the increase of the HEMA, the hardness and brittleness of the coating.
Because H E M A is single hydroxyl compounds, and the reaction of polyurethane prepolymer sealing side effect, not excessive use, otherwise will make the macromolecule emulsifier was closed at both ends. This kind of large molecules more double bonds in the subsequent polymerization have the effect of crosslinking agent, excessive cross-linking led to the decrease of the PUA dispersion particle coarsening, transparency, and storage stability, may also be synthetic gel.
When HEMA is used, the bridge between pa-pu is poor and the film is water-resistant. HEMA amounts to 2.5% ~ 4.0% of the solid total.
DEGDA causes the formation of local crosslinks in polyacrylates, and excessive cross-linking makes the coating brittle. Because of the crosslinking reaction occurred in the process of polymerization of vinyl monomer, so DEGDA can't dosage is too large, according to the amount of acrylic ester, DEGDA dosage is 0.7% ~ 1.5%.
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
Methyl methacrylate (GMA) can improve the water resistance of the coating and increase the resistance to ethanol and acetone. The dosage of the coating is obviously decreased, so it is reasonable to control its dosage, which can be increased to 2% ~ 10% of acrylate.
DAAM and ADH are used in conjunction with a normal weight ratio of about 2:1 or so [4], and DAAM is 8 to 10 percent of acrylate. DAAM is added before the polyacrylate polymerization, because it is soluble in water, and it can be mixed with a small amount of water before it is mixed with the urethane water. ADH in PUA cooled to 50 ℃ below add after polymerization, ADH soluble in water, directly add stir more than 0.5 h can be dissolved completely.
Multiple cross-linked PUA performance. The construction performance and drying performance are the same as that of regular PUA dispersion. The coating was not whitened by 24h, and the anti-ethanol wiper was up to two times, and the resistance of acetone was three times higher.
Multiple cross-linking PUA dispersion base performance. Various crosslinking methods set at an organic whole, adjust the proportion of each component, to the reasonable coordination, and avoid excessive crosslinking, preparation of the PUA some multiple crosslinking, thus proving the feasibility of the method. The dispersion is stable, and the amount of hard and hard monomer can be coated with different hardness.
Coating with good resistance to water, water is not white, ethanol and acetone cleaning resistance than ordinary PUA dispersion coatings have obviously improved and can be used in the manufacture of waterborne wood coatings.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Diethyl toluene diamine(DETDA) http://www.yaruichem.com
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