News Details
Polyurethane (PU) coating crosslinking agent
2017-9-1 12:17:20
Polyurethane (PU) coating crosslinking agent
Water crosslinking polyurethane (PU) waterproof coating market, with its wide range of USES, excellent performance, simple construction, environmental non-toxic, broadly welcomed by the masses of workers with the owner, is better able to grasp its performance and use, the polyurethane (PU) coating crosslinker crosslinked principle and application are discussed.
It is generally considered that mocha is polyurethane (PU) paint crosslinking agent, PU coating is afraid of water, why can it be polyurethane (PU) paint crosslinking agent? So let's talk about the isocyanate and the water reaction mechanism. Isocyanates react with water to produce unstable amino acid, which is then decomposed into carbon dioxide and amine.
If in the presence of excessive isocyanate, the generated amine will continue their reaction with isocyanate, generated instead of urea, said their reaction process is as follows: R - NCO + H2O R - HNCOOH slow fast R - write NH2 + CO2 + R - R - NCO NH2 fast due to R - R - NHCONH - R NH2 with R - NCO's response is faster than water, so the above reaction can be written as: 2 R - NCO + H2OR - NHCONH - write R + CO2
By the above equation can be seen, a water molecule can react with two - NCO groups, the water can be regarded as a form of chain extension agent and crosslinking agent, can replace expensive card, make the molecular chain, forming polymer (polyurea).
According to the above principle, combining with the coating production of foreign latest technology, water crosslinking polyurethane waterproof coating based on polyether polyols and isocyanates addition reaction of the isocyanate group macromolecules (NCO) to polymers, plasticizers, fillers, gas removal agent such as ingredients, one-component packaging factory without solvent coatings.
During construction, the added material will be 20 to 30 % of water, which can be sprayed or sprayed evenly, and can be poured and poured into a series of waterproof, sealed, insulated and paving materials.
The performance and index water crosslinking PU waterproof coating film is compact high strength polyurethane elastomer, enterprise standard Q/sdks-23-2003 in guangdong province for record. The performance index is higher than the national standard of GB/t19250-2003 for polyurethane waterproof coating, and it is also in line with the national standards for products not to deal with the harmful effects of human life and environment.
Water crosslinking dry quickly current commercially available one-component moisture (humidity) pay zone water coating with good performance and convenient construction, won the users, but often because of the air humidity is insufficient, the crosslinking time longer, because can't thick coating, need many times brushing, thus delay the construction period.
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
Water crosslinking polyurethane (PU) waterproof coating market, with its wide range of USES, excellent performance, simple construction, environmental non-toxic, broadly welcomed by the masses of workers with the owner, is better able to grasp its performance and use, the polyurethane (PU) coating crosslinker crosslinked principle and application are discussed.
It is generally considered that mocha is polyurethane (PU) paint crosslinking agent, PU coating is afraid of water, why can it be polyurethane (PU) paint crosslinking agent? So let's talk about the isocyanate and the water reaction mechanism. Isocyanates react with water to produce unstable amino acid, which is then decomposed into carbon dioxide and amine.
If in the presence of excessive isocyanate, the generated amine will continue their reaction with isocyanate, generated instead of urea, said their reaction process is as follows: R - NCO + H2O R - HNCOOH slow fast R - write NH2 + CO2 + R - R - NCO NH2 fast due to R - R - NHCONH - R NH2 with R - NCO's response is faster than water, so the above reaction can be written as: 2 R - NCO + H2OR - NHCONH - write R + CO2
By the above equation can be seen, a water molecule can react with two - NCO groups, the water can be regarded as a form of chain extension agent and crosslinking agent, can replace expensive card, make the molecular chain, forming polymer (polyurea).
According to the above principle, combining with the coating production of foreign latest technology, water crosslinking polyurethane waterproof coating based on polyether polyols and isocyanates addition reaction of the isocyanate group macromolecules (NCO) to polymers, plasticizers, fillers, gas removal agent such as ingredients, one-component packaging factory without solvent coatings.
During construction, the added material will be 20 to 30 % of water, which can be sprayed or sprayed evenly, and can be poured and poured into a series of waterproof, sealed, insulated and paving materials.
The performance and index water crosslinking PU waterproof coating film is compact high strength polyurethane elastomer, enterprise standard Q/sdks-23-2003 in guangdong province for record. The performance index is higher than the national standard of GB/t19250-2003 for polyurethane waterproof coating, and it is also in line with the national standards for products not to deal with the harmful effects of human life and environment.
Water crosslinking dry quickly current commercially available one-component moisture (humidity) pay zone water coating with good performance and convenient construction, won the users, but often because of the air humidity is insufficient, the crosslinking time longer, because can't thick coating, need many times brushing, thus delay the construction period.
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
Water crosslinking PU waterproof coating can overcome the above shortcomings, under the condition of 23 + 2 ℃, table dry 4 h, or less work 12 h or less. Not affected by the size of the air humidity, low temperature and catalyst by heating water to guarantee the crosslinking time, generally - 5 ℃ above can be carried out under the temperature of the construction.
With advanced production technology, the content of free toluene diisocyanate is less than 0.5%, which is a waterproof coating which conforms to hbc12-2002 "environmental product technical requirements", which can be used in the ecological products of drinking water engineering.
Accord with GB/T19250-2003 polyurethane waterproof coating, the fourth chapter "products should not be included in this standard body harmful effects to the environment, involved in safety and environmental requirements related to the use, should comply with the relevant national standards and norms in our country."
The modified epoxy crosslinking agent can shorten the crosslinking time, and the effect is better than that of the catalyst before modification. At the same time, also found that the appearance of the epoxy modified before and after the coating has obvious changes, both at 180 ℃ and 200 ℃, its flow leveling effect is better than before modification coating effect.
This is due to the melting point of epoxy crosslinking agent is as high as above 200 ℃, the melting temperature of epoxy resin has been rapid crosslinking, crosslinking agent and epoxy hybrid implementation in the form of the former suspended. The relative density of epoxy crosslinking agent is greater than that of epoxy resin, and its particle size and crosslinking speed are closely related.
The modified epoxy crosslinking agent can effectively reduce the crosslinking system temperature, improve crosslinking rate and dispersity, shorten the time of crosslinking, and improve the fluidity of the coating.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Water crosslinking PU waterproof coating can overcome the above shortcomings, under the condition of 23 + 2 ℃, table dry 4 h, or less work 12 h or less. Not affected by the size of the air humidity, low temperature and catalyst by heating water to guarantee the crosslinking time, generally - 5 ℃ above can be carried out under the temperature of the construction.
With advanced production technology, the content of free toluene diisocyanate is less than 0.5%, which is a waterproof coating which conforms to hbc12-2002 "environmental product technical requirements", which can be used in the ecological products of drinking water engineering.
Accord with GB/T19250-2003 polyurethane waterproof coating, the fourth chapter "products should not be included in this standard body harmful effects to the environment, involved in safety and environmental requirements related to the use, should comply with the relevant national standards and norms in our country."
The modified epoxy crosslinking agent can shorten the crosslinking time, and the effect is better than that of the catalyst before modification. At the same time, also found that the appearance of the epoxy modified before and after the coating has obvious changes, both at 180 ℃ and 200 ℃, its flow leveling effect is better than before modification coating effect.
This is due to the melting point of epoxy crosslinking agent is as high as above 200 ℃, the melting temperature of epoxy resin has been rapid crosslinking, crosslinking agent and epoxy hybrid implementation in the form of the former suspended. The relative density of epoxy crosslinking agent is greater than that of epoxy resin, and its particle size and crosslinking speed are closely related.
The modified epoxy crosslinking agent can effectively reduce the crosslinking system temperature, improve crosslinking rate and dispersity, shorten the time of crosslinking, and improve the fluidity of the coating.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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