Copper phthalocyanine stability

Very unstable modifications, like the reddish, chlorine-free a-copper phthalocyanine, can be stabilized with amides or salts of copper phthalocyanine sulfonic acids (59—63). Mixture with other metal phthalocyanines, eg, tin, vanadium, aluminum, or magnesium, also inhibits crystallization change and poor performance in binders and prints (flocculation) due to the hydrophobic character of unsubstituted phthalocyanines. 

Knowledge of the most important types of copper phthalocyanine pigments is useful for the understanding of the processes concepts underlying pigment manufacture. Heading the list are the a- and [i-modil i cations of unsubstituted Copper Phthalocyanine Blue (Sec. 3.1.2.3). The a-modification exhibits an unstabilized and a stabilized form as to change of crystal modification. 

This simple one-step route leads to the starting material for the solvent-stabilized a-modification of Copper Phthalocyanine Blue. 

Reaction between phthalic anhydride and urea always affords chlorine-free Copper Phthalocyanine Blue. Chlorinated derivatives are obtained only in the absence of bases (ammonia) or urea. The phase stabilized a-modification is prepared by essentially the same but slightly modified route it is derived from mixed con-... 

Unsubstituted Copper Phthalocyanine Blue is polymorphous. X-ray diffraction diagrams point to five different crystal modifications (a, (3, y, 8, e) (Fig. 91). The relative thermodynamic stability of the individual cystal phases decreases in the following order (3>e>8>a = y [13-16],... 

Phase- and Flocculation-Stabilized Copper Phthalocyanine Blue Pigments... 

There are other metal complexes, such as tin, aluminum, magnesium, iron, cobalt, titanium, and vanadium complexes, which are similarly useful in stabilizing a particular phthalocyanine modification. Moreover, carboxy, carbonamido, sulfo, or phosphono-copper phthalocyanine may be admixed during fine dispersion of the pigment. 

Copper phthalocyanine pigments also demonstrate good overall stability to organic solvents. A number of solvents, however, especially aromatics, may cause a change of modification in unstable types or overcrystallization in stable varieties. This phenomenon is largely due to the tendency of the stable phase to nucleate. The particle size of the resulting cystals decreases as the number of nuclei rises. (3-Copper Phthalocyanine Blue is the thermodynamically stable modification. 

The a- and (i-types of Copper Phthalocyanine Blue reign supreme among commercially available phthalocyanine pigments. There is also an increasing amount of interest in the phase-stabilized form of the a-crystal modification. Both modifications are also supplied as flocculation resistant types. 

As a result of their reddish shade, P.B.15 types are used to a certain extent to color polyethylene, which is processed below 200°C, to produce items such as films. Another suitable medium is PVC, which is commonly treated at moderate temperature. There is a certain disadvantage to the fact that the tinctorial strength of such systems is frequently inferior to that of stabilized Copper Phthalocyanine Blue varieties. 

Incorporated in printing inks, phase-stabilized a-Copper Phthalocyanine Blue, like nonstabilized types, is too reddish to be employed as a process color for three and four color printing. It is used, however, to a considerable extent in all types of printing inks for special and packaging purposes. The prints are stable to common organic solvents and exhibit perfect fastness properties in special application (Sec. 1.6.2.3). Metal deco prints withstand up to 200°C for 10 minutes or 170 to 180°C for 30 minutes. They may safely be sterilized. 

The prints exhibit excellent application properties. They are, for instance, entirely fast to organic solvents, soap, alkali, and acids. They are also fast to sterilization. Metal deco prints demonstrate very good heat stability. The products withstand exposure to 200°C for 10 minutes or to 180°C for 30 minutes. Although not quite as fast to heat as halogenated types of Copper Phthalocyanine Green, P.B.15 3 is thus somewhat more heat stable than stabilized a-Copper Phthalocyanine Blue. 

P.B.15 3, like stabilized a-Copper Phthalocyanine Blue, markedly affects the hardening of unsaturated polyester cast resins. The list of applications also includes PUR foam materials, office articles, such as colored pencils, wax crayons, and water colors, as well as spin dyeing of polypropylene, polyacrylonitrile, secondary acetate, polyamide, polyester, and viscose. Used in polyester spin dyeing, P.B.15 3 satisfies the thermal requirements of the condensation process (Sec. 1.8.3.8). 1/3 and 1/25 SD samples equal step 7-8 on the Blue Scale for lightfastness. Textile fastnesses, such as stability to wet and dry crocking are perfect. 

Under the designation P.B.15 4, the Colour Index lists (3-Copper Phthalocyanine Blue types which are stabilized towards flocculation. These products show largely the same coloristic and fastness properties as P.B.15 3 types, but often exhibit much better rheology. As with stabilized a-Copper Phthalocyanine Blue types, stabilization through surface treatment has proven to decrease the solvent fastness of 3-Copper Phthalocyanine Blue, sometimes considerably so, making the pigment more sensitive to aromatics, alcohols, ethylene glycol, and ketones. 

Stabilized types of 3-Copper Phthalocyanine Blue are becoming increasingly important throughout the printing inks and paints field. Improved stability to flocculation and other rub-out phenomena [29] make P.B.15 4 an attractive choice,... 

Phthalocyanine Blue. P.B.16 also lends color to plastics, although to a more limited extent. It is not as heat stable as stabilized a- or (3-Copper Phthalocyanine Blue types. P.B.16 is also used for artists paints. 

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