Лако-красочные материалы — производство

The properties described qualify benzimidazolone pigments for applications such as high quality industrial paints, including automotive finishes and special effect paints, plastics and high performance printing inks. The colorants are available in the form of powders, masterbatches, liquid dispersions, pastes and granules (see Table 10.4).

Whether or not a pigment fits the technical requirements of a certain target ap­plication is determined by its application properties, which in turn depend on the chemical constitution and the physical parameters of the pigment. Some impor­tant physical data, including hue angles, densities and median particle size distri­butions for some commercially available pigments are given in Table 10.1. Figures

10.3 and 10.7, respectively, show the reflectance and particle size distribution curve for a representative benzimidazolone pigment (Hostaperm™ Yellow H3G).

Detailed spectrometric data for five commercial benzimidazolone pigments are given in Table 10.2.

The particle size distribution curve of Hostaperm™ Yellow H3G (P. Y. 154, see Figure 10.7) was determined using a transmission electron microscope. The data are presented as differential and as cumulative distributions, respectively. The excellent fastness and flow properties of Hostaperm™ Yellow H3G are in good accordance with the small proportion of particles less than 0.1 pm in diameter and the general observation that extremely fine particles exert a detrimental effect on fastness and flow properties.

The reflectance curve of Hostaperm™ Yellow H3G between 400 nm to 700 nm (Figure 10.6) reveals that the pigment “absorbs” violet, blue and blue-green light while it reflects the green, the yellow and red range of the spectrum. Thus, the colorant appears greenish yellow.

As mentioned above, techniques to influence and control the application prop­erties of a given pigment have been developed enormously, in particular within the last two decades. While it is true to say that a pigment is “suitable” for a cer­tain application, it is also true to say that today’s pigments are tailor made (or modified) to satisfy the demands of a given application. Consequently, a pigment cannot be characterized like a classical chemical compound, which is described by fixed physical data and chemical composition. Instead, a pigment should be con­sidered as material that lends its individual profile to potential applications. Bear­ing this in mind, the following brief overview of commercially available benzimid­azolone pigments is given below (compare also Table 10.4). One should also recall that few azo pigments are suitable for the coloration of polyamide.

P. Y. 120 is a very bleed resistant medium yellow pigment that combines good thermal stability with high tinting strength and excellent fastness to light. It is pri­marily used in plastics.

P. Y. 151 has a clean greenish yellow shade. The pigment provides access to very lightfast and durable coatings and shows excellent fastness to migration in plasti­cized PVC. It is used in particular for high grade industrial paints but also plays a role in the coloration of plastics and lightfast prints.

P. Y. 154 is a somewhat greenish yellow pigment having outstanding fastness to light and weathering. In fact it is one of the most weatherfast organic yellow pig­ments available. P. Y. 154 is used throughout the coatings and paints industry, including automotive finishes. The pigment also exhibits excellent fastness prop­erties in printing ink and plastics. However, because of its unsatisfactory tinctorial strength it has not gained much importance for these applications.

P. Y 175 has a very greenish yellow shade. It combines very good fastness to light and weathering with good flow properties in paints. The pigment is used in high performance coatings, such as automotive finishes and refinishes. It is of interest for high grade inks and plastics, where excellent light — and weatherfast­ness properties are required.

P. Y. 180 is a very heat stable greenish to medium yellow disazo pigment that does not affect the shrinkage of plastics. Thus, it is primarily used in plastics, including polymers such as PVC, polycarbonate, polyester, and polystyrene. Additionally,

P. Y. 180 is ofinterest in polypropylene spin dyeing and in heat stable printing inks or paints.

P. Y. 181 represents a reddish yellow pigment with excellent heat stability and lightfastness. It is especially suitable for polymers that are processed at higher temperatures. P. Y. 181 plays a role in the coloration of such plastics as polyacetals, polystyrene or polyester, as well as in spin dyed viscose rayon and viscose cellu­lose.

P. Y. 194 is a yellow pigment of high tinctorial strength with good flow proper­ties in paint. It is mainly applied in industrial coatings and in the coloration of plastics. For such applications, P. Y. 194 is preferred due to its advantageous price/ performance ratio.

P. Y. 213 was released most recently onto the market. This greenish yellow qui — noxalinedione pigment combines outstanding weatherability and overspray resis­tance with an excellent fastness to solvents, acid and alkali. These properties ren­der P. Y. 213 particularly suitable for modern car finishes, especially water based coating systems [11].

P. O. 36 affords a reddish orange shade. Because of its very good light-, weather — and overcoating fastness it is used mostly in high grade plastics and in high qual­ity paints, including automotive finishes. It is also of interest throughout the printing ink industry, wherever stringent demands concerning light — and weather­fastness have to be satisfied.

P. O. 62 is a very opaque, extremely yellowish orange pigment that produces deep, clean, light — and weatherfast shades. It is used throughout the paint industry including automotive finishes as well as in refinishes and in general industrial paints.

P. O. 64, a very heat stable yellowish orange, is used mainly in plastics. It does not affect the shrinkage of partially crystalline polymers. For special applications it is also used in printing inks.

P. O. 72 is a yellowish orange of high heat stability and excellent light fastness.

It does not induce warping in partially crystalline plastics and can be used for spin dying as well.

P. R. 175 is a somewhat dull red pigment with good fastness properties. Its field of application includes paint as well as plastics. P. R. 175 plays a role in transpar­ent metallic automotive finishes and in the dyeing of PVC, for example.

P. R. 176 affords a bluish red shade. This pigment exhibits excellent fastness to migration and light. It is primarily used in plastics (e. g. PVC, polyolefins, poly­acrylonitrile) and in laminated papers.

P. R. 185 is a heat stable bluish red pigment of very high tinctorial strength that has excellent solvent fastness and migration resistance. Its main applications comprise graphics printing and mass coloration of plastics such as PVC and poly­olefins. P. R. 185 is also used in general industrial finishes.

P. R. 208, a bleed resistant medium red pigment with high tinctorial strength, is mainly applied in the mass coloration of plastics and in packaging gravure print­ing.

P. V. 32 is a somewhat dull, very bluish red heat stable pigment of very high tinc­torial strength which is resistant to overpainting. The pigment is used in paints, plastics and printing inks as well as in spin dyeing.

P. Br. 25 provides a reddish shade of brown. It has excellent fastness properties in paints as well as in plastics, and does not cause warpage in HDPE. Because of its high transparency it is especially suitable for metallic and pearlescent effect coatings, to which it lends a beautiful copper tone.

10.6