Compound Ferric Green fade Cause Analysis
Compound Ferric Green is a phthalocyanine blue and yellow iron combined with fillers and additives composed of inorganic and organic pigments transversely across the longitudinal series pigments, fillers, additives and several major areas of material compatibility seemingly simple but actually very complex, a little not Shen is no green, yellow remaining. Now Compound Ferric Green fade reasons are listed below:
one. Phthalocyanine blue unsatisfactory weather resistance and light resistance are the main cause of fading Compound Ferric Green:
We have selected 15: 3 phthalocyanine blue BGS, although any technical articles have claimed that their weather resistance 5, lightfastness 7-8, however Zhule Yi's "silicon-acrylic latex from natural sun exposure observed weather "of the paper opened a phthalocyanine blue truth:
Four kinds of pigments prolonged sun exposure results in silicon-acrylic paint
(Ciba paste, color depth of 1/20 dilute color)
Seen from the data in a year or so after prolonged sun exposure phthalocyanine blue discoloration of the most obvious, obvious yellowish.
α type is unstable state, aromatic hydrocarbon solvents, or subjected to high temperatures will be transformed into crystalline coarse β-type. Form is the result of changes in pigment color light by a bright blue to blue-gray color strength dropped significantly. Although theoretically only at> 200 ℃ temperature phase transformation to take place, but I after nearly 12 hours of drying, there appears only a small amount of blue-gray at 103 ℃ in the experiment, so the long-term high temperatures and dry weather will insolation make this crystal transition sooner rather fade.
two. Add a wetting and dispersing additive unreasonable Compound Ferric Green fade times because
Hydrophilic wetting agent to enhance wetting of the pigment agglomerates, and dispersion aid stable dispersion and prevent flocculation does not control, can make a reasonable amount of pigments to achieve the desired dispersion effect, not only can improve the coloring power can also stable long color consistency throughout the system.
Acrylic emulsion as a film-forming binder, alter the hydrophilic dispersant 1, the amount of hydrophilic wetting agent 2, other materials remain unchanged, dubbed paint formula as follows:
Will make a good model for phthalocyanine blue paint soaked through 2h (3 cycles), 1 to start the recipe recipe 6 color shades, shades are basically the same, after three cycles significantly different color bubble. Gradually increase according to formula 1 to 6 Formulation added hydrophilic additives, enhanced by the film hydrophilic pores thicker, faded during the blister, white, that is hydrophilic, porous paint film colored pigment migration rate is greatly improved.
This is our current Compound Ferric Green in the rain under the impact more easily fade reasons. Our current product wetting and dispersing agent is about three times the phthalocyanine blue, a high proportion of wetting and dispersing agents there are two results in pigments:
1. Cement products in excess wetting and dispersing agent to the pigment migration rate greatly increased, resulting in discoloration.
2. Effective wetting and dispersing agents lack the pigment dispersion is not enough, coloring power and reduced hygroscopicity. Our current wet process using a high speed stirring dispersing machine, in order to meet the requirements of stirring, the water content is at least more than 60%, due to strong hydrophobic phthalocyanine blue, using a highly hydrophilic wetting agent (HLB value is large ), a low HLB value of the dispersant was not any use, it tends to cause a wetting agent in an aqueous medium, a considerable portion of the wetting agent and phthalocyanine blue separated color strength after air drying and reduced hygroscopicity.
I was in a planetary mixer cement paste, by product formula, using phthalocyanine blue 10% A and 5% B wetting agents and dispersants mixing with water, add the remaining material after full uniform mixing, using semi-dry, with a total water the amount of 40% or less, the pigment after 103 ℃ drying and grinding, dubbed cement blocks, coloring power than the standard high.
Summing up the above reasons fade, draw the following personal point of view:
1. Using less α-type phthalocyanine blue BGS.
2. Control wetting and dispersing agent in an amount of 20% or less of the amount of phthalocyanine blue, and phthalocyanine blue and wetting and dispersing agents alone to add water and stir.
3. Mixing equipment such as the use of a kneader, the total amount of water can be controlled semi-dry production at about 30%. Such as a planetary mixer, the total amount of water controlled at about 40% rate in two stages, slow 40 rev / min, rapid 100 r / min or more.
This article comes from oky61 edit released