The polyurethane coating USES crosslinking agent

The polyurethane coating USES crosslinking agent

Influence factors of the properties of water based polyurethane. The relationship between acid price and resin performance. Left of water-soluble rely mainly on resin molecules in resin carboxyl (-cooh) group - functional group by amine and salt formation, resin acid value shows that the molecular structure of resin containing carboxylic acid groups, sensuality in the design of waterborne polyurethane resin synthesis of monomer mass fraction (DMPA), the size of the acid value directly affect the stability of the resin system of water soluble and water soluble. High acid value, good water soluble resin, low viscosity, but poor water resistance. Acid value control in 30 ~ 50 mg KOH/g is suitable.

The relationship between acid price and performance. The effect of 2nOH/nNCO on performance. In the synthesis of polyurethane resin, synthetic system of total different cyano (NCO) to the total ratio of hydroxyl (OH) - design is an important parameter. The molar ratio of different total hydroxy and total different cyano will affect the performance of the resin, such as viscosity, molecular weight, and affect the performance of the resin film coating. The different of nNCO/nOH, the fixed resin acid value and the contrast experiment under the condition of high solids, the results are shown in table 5, comprehensive comparison of nNCO/nOH ideal ratio should be controlled in 1. 1 ~ 1. 2.

The relationship between different cyanate monomer and resin properties. In the synthesis of waterborne polyurethane resin, in order to adjust the flexibility of the coating, with aromatic diisocyanate in formula design of DI (T) and aliphatic diisocyanate (HDI) to adjust the two isocyanate monomer.

Resin with TDI preparation, due to the structure introduced in the polymer chain is of benzene ring rigidity, reduce the polyurethane polymer chain flexibility, coating high hardness, brittle, flexibility is poor; Preparation with HDI resin with low fat link rotating free energy, the polyurethane molecular chain rigidity reduce resin has good flexibility, low hardness, coating limp. Using aromatic diisocyanate (TDI) and aliphatic diisocyanate (HDI) two kinds of isocyanate monomer for copolymerization, which can realize sofe, complementary advantages.




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


Polyurethane resin is difficult to dissolve or disperse in water directly compound solvent to form uniform and stable colloidal system, but its side chain containing reactive carboxyl (-cooh) group, the functional group to add resin neutralizing amine salt and water soluble. The reaction of water soluble () in the formation of aqueous binders.

Amount and types of amine resin hydration and hydration of beads has greater effect on the performance of the coating after. Choice of ammonia, a ethanolamine and triethylamine, ammonia neutralization coating dry quickly, smells great, triethylamine is a cheap ethanol amine, waterborne polyurethane resin is suitable for the amination agent, dosage of system to final finishing of pH = 8. 5 ~ 9. 5.

Water composite low carbon alcohol ether solvent. Water-based paint solvent is given priority to with water, but the polarity of the water is too large, the solubility of the resin and wetting ability is small, if it is difficult to form with water as the only solvents meet the performance requirements of water-based coating preparation uniform and stable water-based binders, therefore, water-based paint using solvent other than water, should also be distribution can improve water-based resin salt soluble cosolvent.

The cosolvent can dissolve the selected resin and its salts, and can in any proportion of immiscible with water, and non-toxic, no smell, burning, the boiling point of latent heat and dry coating requirements. This kind of cosolvent commonly used with alcohols: such as ethanol, isopropanol, etc; Alcohol ether: such as ethylene glycol ether, propylene glycol ether, etc.). Water-based paint solvents used for lower alcohol is given priority to with water or alcohol ether is complementary composite solvent system, the following basic components: n ethanol: n isopropyl alcohol: n glycol ether: n water = 3:3:1:3.

Water-based decorative paint color is depend on the paint to express, to adapt to the coating of ability in the preparation of paint must be alkali resistance and good dispersibility. Using high solids is the most suitable pigment filter cake, the tinting strength can be increased by 5% ~ 15%, bright color, low viscosity, stability and the high cost. In order to reduce costs, choose bright color of organic pigments, such as lithol scarlet, everbright red toner, pretty, phthalein wellknown blue, phthalein wellknown green and benzidine yellow, solid yellow and so on, choose white, white black choose high carbon black pigment, filling colloid calcium carbonate. The construction technology of water-based coatings eligibility most through proper additives for adjustment, such as wetting dispersing agent, defoamer, etc.

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Diethyl toluene diamine(DETDA)  http://www.yaruichem.com