2021-10-21 Pageview:717
The reference dosage is 0.05-0.35%, adding 0.5-3.5KG per ton of product, the dosage depends on different seasons, different kinds of emulsions, different product protection and the degree of microbial contamination.
If the alkyd enamel is formulated with rutile titanium dioxide, the order of adding the tenth agent has a different effect on the dryness. The effect of adding lead, cobalt and calcium to the paint after mixing in advance is poor, while adding cobalt-lead to the paint and adding calcium drying liquid has a better effect.
Effect of drier on coating performance
The drier can not only accelerate the drying of the oil-based paint, but also affect other properties. If used improperly, it will cause storage problems such as increased viscosity, jelly, skinning and muddy, and can also cause the coating film to appear wrinkled, Defects such as air lines, dew, blooming, loss of gloss, poor water resistance and weather resistance.
Crust
Oil-based paint is conjunctival due to oxidative polymerization, so the skinning during storage is generally considered to be a normal phenomenon. A large amount of tung oil in the binder, a large degree of polymerization, and an excessive amount of cobalt drier can cause serious skinning of the coating.
Quick-drying enamel paint is easier to crust than oil paint. Generally, it can reach an immiscible gel state after overnight, and the resulting skin is harder.
Muddy
Lead driers used in alkyd varnishes will become muddy after a few weeks of storage due to the formation of insoluble lead phthalate. The degree of turbidity varies with the amount of lead drier and the type of resin. eaa emulsion paint Alkyd resins with high acid value are prone to muddy. When turpentine is used as a solvent, it is easy to become muddy, because the water contained in it accelerates the hydrolysis of alkyd resin and releases phthalic anhydride.
The storage temperature is high and it is easy to become muddy. Long oil linoleum pentaerythritol alkyd resin (0.5% lead, 0.05% cobalt) becomes muddy at room temperature for 24 weeks, and at 40°C for 8 weeks.
Adding calcium naphthoate can effectively prevent the precipitation of lead salt, and the dosage is half of the lead drier. Dilute the alkyd varnish to 0.3Pa·s and conduct an accelerated test in a 40℃ oven. Adding calcium naphthalate can effectively prevent the precipitation of lead salts and become muddy.
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