Introduce of Titanium dioxide weather fastness

Titanium dioxide weather fastness is one of the most important performance of its application performance,and normally weathering index is composed of light resistance,gloss retention,resistance to pulverization of several aspects.Please listen to the answer below.

We know,weather fastness is,when titanium dioxide exposure to sunlight, corrode by oxygen and moisture,can resist such erosion,and avoid yellowing immortality,loss of gloss and pulverization ability.Because pigment system will show the typical color change or structural changes once under intense radiation or under climate impact.The most obvious change is turning yellow,pulverization,and loss of light.These processes involve the photochemical reaction,the reaction have the effect of catalyst,paint or paint itself just has a chemical change.

Titanium dioxide has high activity of photochemical activity,in the condition of exposure under sunlight where there is water,its oxygen ion on crystal lattice will lose two electron turn into oxygen atom,the nascent state of oxygen has extreme activity,can oxidize organic substance,make polymer chain scission,degradation of organic matter,and ultimately make the coating chalking,losing gloss,yellowing,color changing,and lead to lower weatherability.Whether produced by sulphate process with Hydrolysis and calcination technology or chloride process gas phase oxidation process,the titanium dioxide still has some lattice defects,it is called schottky defect, there are many photoactivation on particles surface,will accelerate its photochemical reaction,causing key free radicals reaction and the destruction of organic media such as coating.

Pulverization is due to increased organic adhesive separating from coating surface,leaving the titanium dioxide and extender agent particles exposed to the air, these particles are white,then form the appearance of powder pulverizing.This change will lead to the change of color and luster fade,continuous damage to paint finishing can lead to loss of light,and in protecting light under the influence of the climate is very important.If the basic material was badly damaged,the paint will be loose,pulverization,occurs pulverization is the definition of when the base was damaged,and them the pigment or filler particles.

Light stability is a material property,is resistance of change of earch radiation, this change may be caused in the presence of humidity.Light and humidity will cause pulverization and make it loss of light and color,light and climate patience generally depends on the chemical composition,structure,defects,pigment particle size and shape,and concentration,etc.These properties associated with accompany pigments used by medium also,you can under the atmospheric weathering test,can also be accelerated aging test,chemical test method can be used.

By Nicole