The composition of the UF toilet

(1) (UF toilet seat)The urea formaldehyde resin used as compression molding powder requires the condensation polymer with a relatively low degree of reaction. At this time, the resin viscosity is small, which is convenient for impregnating the filler, and can ensure that it still has appropriate fluidity after a long production cycle and drying. In industry, the condensation of urea and formaldehyde at low temperature (i.e. the mixture of dihydroxymethylurea) is mostly used. Usually, the ratio of urea to formaldehyde is 1:1.5 (molar ratio). After all dissolved at pH = 8 (and temperature) 30-35 ℃, add 0.3% - 0.54% oxalic acid and 0.33% - 0.88% oxalic acid ester with urea amount, and then exothermic reaction occurs. The temperature rises and remains at 55-60 ℃, and strictly control pH = 5.5-6.5. The required urea formaldehyde resin is obtained after 60-75 minutes. Due to the low degree of polycondensation, in fact, it has just passed the addition reaction stage, and the main polycondensation reaction is carried out in the curing process.

(2) (UF toilet seat)The curing agent used in the curing agent compression molding powder is required to have a certain latency. The commonly used curing agents are oxalic acid, phthalic acid, benzoic acid, monochloroacetic acid, etc.

(3) (UF toilet seat)The most commonly used filler is pulp, followed by wood powder or inorganic filler (asbestos, glass fiber, mica, etc.). The pulp used is pure cellulose obtained by using wood as raw material, sulfite treatment, dissolving non cellulose impurities in wood, and then bleaching. The amount of filler is 25% - 32% of the total material. If the amount is too small, the fluidity of compression molding powder is large and the strength of products is low; On the contrary, when the dosage is too much, the fluidity of compression molding powder decreases, the product surface is not smooth, and the water resistance decreases.