Inorganic Pigments Competence Center Paints

Bayferrox® 943

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BAyFERRoX® 943 is a reddish iron oxide yellow pigment which was launched more than 20 years ago and is proven in practical use. While most iron oxide yellow pigments crystallize to form a Goethite-like lattice (α-FeO(OH)), BAyFERRoX® 943 has the crystal structure of Lepidocrocite (γ-FeO(OH)). The differences are shown in figure 1.

Bayferrox® 943

Crystal structure of Goethite Crystal structure of Lepidocrocite

The differences in the crystal structure lead to a different shape of the pigment particles (figure 2). Compared to BAyFERRoX® 930, which has a pronounced needle shape like nearly all iron oxide yellow pigments, the BAyFERRoX® 943 particles have a significant lower aspect ratio. That means the relationship of length to thickness is significant smaller. Thus the BAyFERRoX® 943 shows a different viscosity behavior

electron micrograph of Bayferrox® 943

electron micrograph of Bayferrox® 930

figure 1:

in pigment preparations. Due the low aspect ratio this pigment produces also a much less silking effect than other iron oxide yellows.

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Coloristic Properties The difference in the crystal structure has an influence on the light absorption respective on the reflectance (figure 3) and with that on the coloristic properties.

Bayferrox® 943

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figure 3: Spectral reflectance of Bayferrox® 943 in comparison to Bayferrox® 930

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Bayferrox 930

Bayferrox 943

Caused by the difference in the light absorption, this product is characterized by its reddish, relative brilliant color shade and high tinting strength. The color shade of BAyFERRoX® 943 is special compared to other iron oxide pigments (figure 4). One can reach areas in the color space which are normally not ac-cessible for iron oxide pigments alone.

Shade as generated by printing technique used. 100 % color accuracy cannot be guaranteed due to printing techniques.

full Shade 1:5 reduction with Tronox® r-KB-2

Viscosity BehaviorAs mentioned before the pigment crystallizes in very short nee-dles. Beside that the shape of the crystals is the reason for an interesting low viscosity behavior in pigment preparations, even at high shear rates, which is of special importance if the pigment preparation is used in tinting machines (figure 6).

Bayferrox® 943

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Bayferrox 910 Bayferrox 920 Bayferrox 930 Bayferrox 943

figure 5: Coloristic properties of Bayferrox® 943 compared with regular Bayferrox® yellow types, reduced with Tronox® r-KB-2 in different ratio’s (1 : 0; 1 : 1; 1 : 5; 1 : 10; 1 : 25 with pvc 10 % in medium oil alkyd)

figure 6: Viscosity behavior in a universal colorant (52% solids) at different shear rates

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Cone-Plate Rheometer

Figure 5 shows the coloristic behavior of BAyFERRoX® 943 in comparison to regular iron oxide yellows in full shade and in various reductions with titanium dioxide. Although BAyFERRoX® 943 is an iron oxide pigment, its performance properties differ from those of the other BAyFERRoX® products.

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Heat stability of Bayferrox® 943 in SILIKoPHen® P80x (full shade) (45 mi-nutes at the mentioned temperature). Shade as generated by printing technique used. 100 % color accuracy cannot be guaranteed due to printing techniques.

figure 8: Color deviation of Bayferrox® 943 in SILIKoPHen® P80x (full shade), versus temperature (treated 45 minutes at the respective temperature)

Heat StabilityThe heat stability of the product is similar to that of the other iron oxide yellows. The pigment powder is unaffected by temperatures up to approx. 180 °C. In coating systems the binder has a certain stabilizing function regarding the heat

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stability. Depending on the system, the pigment could be used at temperatures up to slightly above 200 °C (figures 7 and 8). It is always recommended to check the limits of the heat stability in the original system under the intended conditions.

Weather and Chemical StabilityBAyFERRoX® 943 also exhibits the excellent weather stability found in other iron oxide pigments. A system based on a weather-stable binder and pigmented with BAyFERRoX® 943 will exhibit similar properties to systems colored with other BAyFERRoX® pigments. Color retention is slightly poorer in systems based on sensitive binders. It is always recom-mended that the user carries out trials.

Like all iron oxide pigments BAyFERRoX® 943 is resistant to alkalis and completely insoluble in organic media.

UsesBAyFERRoX® 943 can universally be used in all coatings systems. In powder and coil coatings the limited heat stability must be considered.

The clean reddish undertone makes the pigment perfect to reach a number of pastel tones which are normally not ac-cessible with iron oxide yellow alone. Due the relative clean color shade and high tinting strength and the low viscosity behavior the pigment has also a high performance in tinting systems.

Bayferrox® 943

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Beside the coatings application, BAyFERRoX® 943 is suit-able for use in plastics, as long as they do not require high heat stability. Another popular application for BAyFERRoX® 943 was found in laminated paper.

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LANXESS Deutschland GmbHBusiness Unit Inorganic PigmentsCompetence Center Paints47812 Krefeld, Germany

www.lanxess.comwww.bayferrox.de

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has been assembled which provides information con-

cerning the health and safety precautions that must be

observed when handling the LANXESS products menti-

oned in this publication. For materials mentioned which

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manufacturers should be followed. Before working with

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liar with the available information on their hazards, pro-

per use and handling. This cannot be overemphasized.

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safety data sheets, product information and product la-

bels. Consult your LANXESS representative in Germany

or contact the Regulatory Affairs and Product Safety

Department of LANXESS Germany or – for business in

the USA – the LANXESS Product Safety and Regulatory

Affairs Department in Pittsburgh, Pennsylvania.

Regulatory Compliance Information: Some of the end

uses of the products described in this publication must

comply with applicable regulations, such as the FDA,

BfR, NSF, USDA, and CPSC. If you have any questions

on the regulatory status of these products, please con-

sult your LANXESS representative in Germany or contact

the Regulatory Affairs and Product Safety Department of

LANXESS Germany or – for business in the USA – your

LANXESS Corporation representative, the LANXESS

Regulatory Affairs Manager in Pittsburgh, Pennsylvania.

The manner in which you use and the purpose to which

you put and utilize our products, technical assistance

and information (whether verbal, written or by way of

production evaluations), including any suggested for-

mulations and recommendations are beyond our con-

trol. Therefore, it is imperative that you test our products,

technical assistance and information to determine to

your own satisfaction whether they are suitable for your

intended uses and applications. This application-specifi

c analysis must at least include testing to determine

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sarily been done by us. Unless we otherwise agree in

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terms of our General Conditions of Sale and Delivery.

All information and technical assistance is given without

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expressly understood and agreed that you assume and

hereby expressly release us from all liability, in tort, con-

tract or otherwise, incurred in connection with the use

of our products, technical assistance, and information.

Any statement or recommendation not contained in this

brochure is unauthorized and shall not bind us. Nothing

herein shall be construed as a recommendation to use

any product in confl ict with industrial property rights such

as patents covering any material or its use. No license is

implied or in fact granted under the claims of industrial pro-

perty rights such as patents. Edition 02/2011

BAyFERRoX® is a registered trademark of Bayer AG, Leverkusen, Germany.