Benzimidazolone Yellow Pigments: High-Performance Pigment for Paints, Plastics and Inks

In the February-March issue of Turkcoat magazine, we provided an introduction to Benzimidazolone Yellow Pigments. In this issue, we continue from where we left off.

Pigment Yellow: 120

Pigment Yellow: 120 is a medium yellow pigment with good thermal stability, very high tinting strength, excellent light fastness and resistance to bleeding. It is primarily used in plastics. Pigment Yellow: 120 provides a medium yellow colour. As a pigment, it shows good resistance to solvents similar to other yellow pigments in this class. Pigment Yellow: 120 finds its principal application in plastics, especially PVC. A pigment colour paste is available for this purpose. Pigment Yellow: 120 is quite resistant to bleeding in plasticised PVC and shows excellent light fastness in both plasticised and rigid PVC. Samples of 1/1 to 1/25 SD (5% TiO2), as well as transparent formulations, correspond to step 8 on the blue scale for daylight fastness. However, in lead/cadmium-stabilised rigid PVC, this pigment is less resistant to weathering than other pigments of its class, which prevents its use in outdoor applications. Pigment Yellow: 120 demonstrated adequate heat resistance by withstanding 1/3 SD samples (1% TiO2) in HDPE for 5 minutes at 270°C. It is not adversely affected by polymer shrinkage. Pigment Yellow: 120 withstands 220°C in LDPE and 240°C in polystyrene. Opaque samples (0.01% - 0.5% TiO2) have light fastness at steps 6-7 on the Blue Scale, while transparent HDPE colours (0.1%) correspond to step 8 on the Blue Scale. Pigment Yellow: 120 is primarily used in printing inks, especially in decorative printing inks on laminated melamine and polyester resin layers. In terms of light fastness, 8% gravure prints in 20 and 40 μm cells on such plates correspond to step 8 on the Blue Scale. No print shift is observed. Pigment Yellow: 120 is insoluble in monostyrene and acetone.

Pigment Yellow: 151

Pigment Yellow: 151 is in a clean yellowish-green colour tone. This pigment provides excellent light fastness and durable paints and demonstrates excellent migration resistance in plasticised PVC. It is used especially in high-quality industrial paints, as well as in plastics and light-fast printing inks. This pigment has been on the market since 1971 and provides a clean green-yellow tone. It is slightly more green than Pigment Yellow: 154 and distinctly more red than Pigment Yellow: 175. With a specific surface area of less than 20 m2/g, this pigment provides good hiding power. Pigment Yellow: 151 occupies an important place in the pigment industry. Its principal application in the paint industry is in high-quality industrial paints. Its good rheological properties allow pigment concentrations of approximately 30% to be added to the paint composition without affecting paint gloss. The percentage to be given is based on the amount of solid binder. For comparison, it should be noted that the pigment ratio of full-tone paints containing other pigments is generally limited to a pigment concentration of between 10% and 15%. Pigment Yellow: 151 is mostly used in combination with TiO2 and/or inorganic yellow pigments. Combinations of this pigment, which has very good light fastness and outdoor durability, with phthalocyanine green pigments are equally important. Sometimes they are used together with the inorganic pigments mentioned above. As a rule, Pigment Yellow: 151 is used to obtain deeper colour tones. This property makes it an interesting product for automobile manufacturers (O.E.M), automotive top coats, automotive repair paints and commercial vehicle paint manufacturers. Paints containing Pigment Yellow: 151 have very good light fastness and are durable. For example, acrylic melamine resin-based systems kept outdoors in Florida climate for one year and subsequently evaluated showed outdoor durability on the Grey Scale at step 5 when reduced 1:1 with TiO2, while 1:3 TiO2 reductions gave step 4, and 1:35 reduced samples corresponded to steps 3-4. Pigment Yellow: 151 is heat-resistant up to a maximum of 200°C and is acid-resistant; however, under certain test conditions it is affected by alkali. While the pigment shows tolerance to weak bases, in the presence of strong alkalis it will undergo a distinct colour change towards reddish-yellow tones. This pigment is also affected by lime. Its use in emulsion paints is almost completely prevented.

Pigment Yellow: 154

Pigment Yellow: 154 is a light yellowish-green pigment and shows superior resistance to light and weather. It is in fact one of the most weather-resistant organic yellow pigments among known and existing pigments. It is used in the paint and coatings industry, especially in automotive paints. It has excellent fastness properties in printing inks and plastics. However, due to unsatisfactory tinting strength, it has not gained much importance in these application areas. Introduced in the mid-1970s, this pigment is a slightly yellowish-green pigment with very high light fastness and outdoor durability. The colour tone is distinctly more red than Pigment Yellow: 175 and distinctly more red than P.Y. 151, both members of the benzimidazolone series. Pigment Yellow: 154 is almost completely resistant to all solvents or at least to the main organic solvents. The list includes alcohols, esters such as butyl acetate, aliphatic and aromatic hydrocarbons, such as mineral spirit or xylene and dibutyl phthalate. It is applied primarily in paints as one of the weather-resistant organic yellow pigments. When used in the same system and evaluated under the same conditions as Pigment Yellow: 151, for example after exposure outdoors in Florida for one year, TiO2 reductions up to 1:3 correspond to step 5 on the Grey Scale, while 1:30 TiO2 reduction corresponded to steps 4-5. For this reason, this pigment is also a suitable colouring component for other colours and can be used to produce reduced clean yellow and green colour tones.

Pigment Yellow: 175

Pigment Yellow: 175 is a very yellowish-green colour tone. In addition to the good flow properties it imparts to paints, it provides very good resistance to light and weathering. It is used in high-performance paints such as automotive paints and automotive repair paints. It is of interest for high-quality inks and plastics where excellent light and weather fastness is required. This pigment, in a clean and very yellowish-green colour tone, is a relatively new product. It has achieved only limited commercial recognition. The colour tone available on the market is slightly more green than other benzimidazolone pigments and more green than other equivalent coloured pigments such as Pigment Yellow: 109, 128 or 138. It is used especially and primarily in the production of paints used in high-quality systems such as automobile (O.E.M.) and automotive repair paints. It is used to obtain bright yellow or bright green tones. Green colour tones can be achieved, for example, by combining with phthalocyanine pigments. Despite its proportionally low specific surface area (approximately 20 m2/g), the type available on the market exhibits good transparency. However, it is not sufficiently weather-resistant for use in metallic paints. On the other hand, in opaque solid tones it has excellent both light fastness and outdoor durability. In reductions with TiO2, it shows excellent weather resistance, but this resistance deteriorates rapidly when more white pigment is added. These properties are lower than those of P.Y. 154, which is also a member of the benzimidazolone pigment series and is slightly more red. Pigment Yellow: 175 does not bloom. It can safely withstand up to 140°C. At higher temperatures, slight bleeding may be observed in different paint systems. This pigment is heat-resistant up to 180°C. Commercially available types exhibit good rheological properties and can therefore be used at higher concentrations.

Pigment Yellow: 180

Pigment Yellow: 180 is a heat-resistant disazo pigment in a yellowish-green to medium yellow colour tone that is not affected by plastic shrinkage. It is therefore used primarily in polymers such as plastics, PVC, polycarbonate, polyester and polystyrene. In addition, P.Y: 180 is of interest in polypropylene solution dyeing and in heat-resistant inks or paints. This pigment, in a green-medium yellow colour tone, has recently come to market. It is a disazo yellow pigment and is of special importance for the plastic industry. It is heat-resistant up to 290°C in HDPE. It does not affect plastic shrinkage, so there are no restrictions on its use in injection-moulded articles. However, it has less light fastness than the more red P.Y. 181. It is also used for PP filament dyeing because it provides excellent heat stability and clean colour tones. A special pigment colour paste is available for this purpose. More reddish tones can be achieved by combining with the very reddish P.Y. 181. Full-tone colours have excellent light fastness. When white pigment is added, light fastness decreases rapidly. However, 1/25 SD samples correspond to step 5 on the Blue Scale. Pigment Yellow: 180 shows excellent performance in the textile industry in terms of durability properties. It is gaining increasing importance and is also used in printing inks for certain applications where diarylide yellow pigments cannot be used. Diarylide yellow pigments decompose at temperatures above 200°C; this prevents certain inks used in metal decoration printing from being baked at temperatures above 200°C.

Pigment Yellow: 181

Pigment Yellow: 181 is a reddish-yellow benzimidazolone class pigment with excellent heat resistance and light fastness. It is particularly suitable for polymers processed at high temperatures. It is used in the colouring of plastics such as polyacetals, polystyrene or polyester, as well as in solution dyeing of viscose artificial silk and viscose cellulose. Pigment Yellow: 181, a reddish-yellow pigment, has been introduced to the market in recent years. Its principal application is in plastics, especially polyolefins. In these binders, it is heat-resistant up to 300°C and has very good light fastness. It partially does not affect crystalline polymer shrinkage. However, its tinting strength is weak. It does not migrate in plasticised PVC. In addition, it shows excellent light fastness in this binder. Both its transparent samples and white-reduced samples correspond to step 8 on the Blue Scale.

Pigment Yellow: 194

Pigment Yellow: 194 is a yellow pigment with good flow properties in paint and high tinting strength. It is especially suitable for industrial paints and plastic colouring. For such applications, Pigment Yellow: 194 is preferred due to its advantageous price/performance ratio. It provides medium yellow tones. In terms of colour tones and performance, it competes with other pigments such as monoazo Pigment Yellow: 97 and bisacetoacetylarylide Pigment Yellow: 16. Pigment Yellow: 194 is gaining increasing importance in both industrial paints and powder coatings. In stoving paints, due to solvent fastness, it is resistant to spray at 120°C. After 30 minutes of baking at 140°C, it may show slight bleeding and is heat-resistant up to 200°C. High hiding power and the associated specific surface area of 20 m2/g support its use for lead-free paints. It is also used in the plastics field. A special type of it provides good tinting strength and particularly good dispersibility. Pigmentation in 1/3 SD (1% TiO2) of HDPE requires 0.17% pigment. The colourings produced are heat-resistant up to 240°C and light fastness corresponds to step 5 on the Blue Scale. The use of the pigment is particularly recommended in LDPE. It can cause bleeding in plasticised PVC. Light fastness in these binders corresponds to steps 5-6 on the Blue Scale depending on standard colour tone depth. In the cable industry, it is used in significant quantities in cable insulation as it only negligibly affects its specific electrical resistance.

Pigment Yellow: 213

Pigment Yellow: 213 is the most recently introduced of this type of pigment. This yellowish-green quinoxalinedione pigment demonstrates excellent resistance to weathering and excessive topcoat resistance, as well as excellent resistance to solvents, acids and alkalis. These properties make P.Y. 213 particularly suitable for modern automotive paints, especially water-based paint systems. M. Namık Kayaalp / Chemical Engineer / Ecelak Boya Kimya Ltd. Şti. References 1. R.P. Schunck and K. Hunger, in: Pigment Handbook, ed. by P.A. Lewis. 2. W. Herbst, K. Hunger, Industrial Organic Pigments 3. High Performance- Pigments. Edited by Hugh M. Smith. 4. Organic Pigments, Lewis.