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Formulation analysis preparation principle of waterborne polyurethane (modified MDI)

2020-07-16 11:37:31

The modified trimer crosslinking agent can be made isocyanates such as TDI, PDI, MDI XDI

(150-200℃。 It has the advantages of no yellowing, white transparent water. It is suitable for water-borne polyamines such as carboxylic acid

Crosslinking agent of ester at room temperature. In order to enhance the comprehensive performance. Formulation analysis preparation principle of diisobluoric acid waterborne polyurethane (modified MDI) with different NCO group activity

The end NCO produced in the reaction should be reacted with polyol carboxylic acid to facilitate neutralization of amine the product

Water solubility. Because of its high melting point, the reaction needs to be carried out in organic solvent by stages

Temperature. Isocyanates can be self polycondensated to form trimer compounds. The content of phosphine in the catalyst is 0

The reaction temperature is low the yield is up to 90%. Then the trimerization catalysis method is used to promote the complete reaction

The residue was sealed

Product formula: NCO: polyol carboxylic acid (mass ratio) is 6:1:1.43

Process steps: polyol carboxylic acid solution preparation, neopentyl glycol, trimellitic anhydride, DMPA, DMPA,

Xylene toluene were added into the reactor stirred to raise the temperature to 80

After dissolution, the temperature was raised to 148 ℃ refluxed

After dehydration to transparent, filter discharge for standby. Preparation of imine prepolymer: adding xylene toluene according to the formula

After refluxing dehydration, add 10% phosphoric acid (toluene) solution to reduce the temperature to 120 ℃

After adding nitrogen, TDI IPDI were added into the monomer dropping kettle. After dropping within 25 hours, the temperature was raised to

After reaction at 130 ℃ for H, 10% phosphine solution was added into the dropping kettle: start to add slowly observe continuously

The reaction condition of the material is to prevent explosive polymerization. The dropping is completed at 130 ℃ for 2h, 140 ℃ for 1H 145 ℃ for 30min

When the temperature is reduced to 70 ℃, the polyol is cooled to 70 ℃. The carboxylic acid solution was added into the dropping kettle reacted at 70 ℃ (2-3)

h. The conversion rate of NCO is 96%. Adding 10% lithium acetate solution: there are two processes: one is to reduce the conversion of NCO

Temperature to 25 ℃, standing for 7d: second, heating to (80-90) ℃ for (2-3) h, measuring free TDI at 03%

Then, 10% methyl p-toluenesulfonate solution 10% dimethylpyrazole solution are added heated to 85 ℃

After 20 minutes of vacuum extraction, 23 organic solvents were removed, then hydrophilic solvents were added to adjust the solid content to 50%

When the temperature is 50 ℃, add 50% triethylamine aqueous solution n-toluene diethanolamine to adjust the pH value to 8

The reaction temperature was 60 ℃ to transparent cooled to 40 ℃.



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