Fastness to bleeding

Bliite /. blossom, flower, bloom, blute t, a. (Dyeing) fast to bleeding. Blut eg , m. leech. eisenstein, m. hematite. 

Detailed methods are also specified in various countries for determining the fastness to bleeding [33], Plate-out frequently occurs in the coloring and processing of PVC particularly on calenders and roll mills. 

In most cases the pigments used are also required to be migration-resistant. The suitability test is also carried out with 5 different pigment concentrations. To test the fastness to bleeding, the unvulcanized colorations are brought into defined contact with a white milled sheet of specific composition and vulcanized wet for 20 minutes in open steam at 140°C. During this process, half the coloration is often covered with a wet cotton cloth to determine whether the cloth, the rubber or both are stained by bleeding. 

Although fast to bleeding in petrolether and dibutylphthalate, very little bleeding is found in ethanol and methoxypropanol and a slight bleeding occurs in toluene, ethylacetate, paraffin and the solvent mixture according to DIN 16 524. 

Their solvent stability is poor, it approaches that of the above-mentioned yellows (Sec. 2.3.3). Migration characteristics, i.e., fastness to bleeding and blooming, are consequently inferior, although the pigments are generally resistant to alkali and acid. 

P.R.53 1 is also very strong in PVC. It is not very lightfast, but a number of disposable articles are colored to advantage with P.R.53 1. However, it has a poor fastness to bleeding. For economical reasons, P.R.53 1 is also employed in polystyrene, in which it is heat stable up to 280°C and moderately lightfast (step 1-2 on the Blue Scale). 

P.R.48 4 does not bloom in plasticized PVC and is almost completely fast to bleeding. Its tinctorial strength in this medium is equally good. Desirable dielectric properties make P.R.48 4 a suitable candidate for use in PVC cable insulations. The pigment is also used for mass colored secondary acetate threads, fibers, and films wherever it meets the requirements for application. 

In plasticized PVC, P.R.242 shows good fastness to bleeding and provides average tinctorial strength. 1/3 SD colorations containing 5% TiOz require 1.1% pigment. Good heat stability makes P.R.242 a suitable candidate for use in polystyrene, ABS, PMMA, and polyester. 

In terms of fastness properties, P.B.15 6 performs like other modifications. In baking enamels, stabilized types are completely fast to overcoating, but they are not entirely fast to bleeding in plasticized PVC. 

P.V.5 1 is used to a certain extent in PVC. Plasticized PVC systems are fast to bleeding and reasonably lightfast in full shades. Addition of Ti02, however, markedly affects its lightfastness. The pigment is heat stable up to 170°C. 

Incorporated in plasticized PVC, P.Y.187 demonstrates moderate fastness to bleeding. At a processing temperature of 130°C, the pigment affords a greenish shade of yellow, while an orange shade is observed at 160°C. 

The fastness to bleeding was determined at 100 C / 15 h against the 5-step Ijleeding Grey Scale (DIN 54002). 

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