SACHTOLITH – White pigment for a wide range of coating applications

SACHTOLITH –White pigment fora wide range ofcoating applicationsGreat Solutions with Small Particles

Great Solutions with Small Particles1SACHTOLITH – the white pigmentbased on pure Zinksulfide. Designedto offer solutions for a wide range ofapplications.Because of its special properties likeMoh’s hardness, UV-absorption edgeand low specific surface area. Theseparticles provide benefits to many applications.

SACHTOLITHThe productSACHTOLITH (CAS Registration No. 1314-98-3)is a white pigment consisting of extremely purezinc sulfide. Highly purified zinc salt and sodiumsulfide solutions, from which all discolorant andtoxic heavy metals have been removed down toppm trace levels, are used for its production.The extremely finely precipitated zinc sulfide isadjusted to the narrow particle-size distributionof approx. 0.3 μm which is optimum for scatter-ing of light by means of calcining at around700° C. Three SACHTOLITH grades are produced:L, HD and HD-S.The SACHTOLITH gradesSACHTOLITH L is the standard grade, with noorganic treatment. SACHTOLITH HD and HD-Scontain small amounts of organic wetting agentsto improve wettability and dispersibility in aqueousand organic media. Thanks to its high-energygrinding process (micronization) and a specialscreening process, SACHTOLITH HD-S is free ofcoarse particles and is easily dispersed. Its opticalperformance is some 10 to 15 % superior to thatof the L and HD grades.2

Properties of SACHTOLITHChemicalIn the >4 pH range, SACHTOLITH is resistant topractically all chemicals. Its solubility in 0.1 mhydrochloric acid is approx. 0.3 %.SACHTOLITH can be oxidized to ZnSO 4by powerfuloxidizing agents or by UV radiation in thepresence of water and oxygen. ZnS is capable ofreacting superficially with additives which containheavy metals, particularly at high processing temperaturesand under exposure to UV radiation.The property of fixing undesirable heavy-metalions can, on the other hand, prevent catalyticcracking of polymers. Unlike TiO 2, ZnS does notgenerate any colored complexes with phenolicanti-oxidants, and reduces the catalytic oxidationof polymers. SACHTOLITH also remains stable upto at least 350° C under exposure to air oxygen.PhysicalSACHTOLITH consists primarily of polycrystallinewurtzite and is an n-type photo semiconductor,like the TiO 2pigments. Under normal conditions,SACHTOLITH is a good isolator (e relapprox. 8). Atapprox. 27 W m -1 K -1 , its thermal conductivity isunusually high for a mineral product, its specificheat, on the other hand, extremely low, at some500 J kg -1 K -1 .Specific surface area and binder requirement arelow and permit good rheological properties evenat high pigmentation levels. In combination withthe pigment‘s low UV absorption, its good lightreflectance in the visible range produces a neutralwhite tone and results in optimum effectivenessof optical brighteners, Day-Glow paints andphotoinitiators.Due to the product‘s lower refractive index (2.37)compared to TiO 2, its scattering power is lowerthan that of rutile by 35 % and than that of anataseby 25 %. Its spherical particle geometry andlow Mohs hardness of 3 mean that SACHTOLITHcauses no abrasion or wear on metallic materials.ToxicologicalSACHTOLITH is a practically insoluble inorganicsubstance containing no harmful or notifiableconstituents. Under correct use, it is non-toxicand is suitable, inter alia, for the pigmentationof toys and foodstuffs packaging materials.SACHTOLITH is registered and approved foruse in a large range of countries; the followingare intended only as examples:Germany:BfR: Meets limitsVwVwS:Not a water pollutantEU:AP 89 (1) and AP 96 (5) Ref. No. 96320EN 71/3Hazardous Substances Ordinance:Not a hazardous in EEC 67/548 ff.Japan:MITI 1-572USA:FDA § 178.3297TSCA 1314-98-3Clean Air Act Amendments: Not listedHazardous Air Pollutants: Not an air pollutant3

Technical Data of SACHTOLITHSACHTOLITH L HD HD-SZnS [%] approx. 98 98 98Volatile constituents (105° C) [%] DIN EN ISO 787-2 approx. 0.2 0.2 0.2pH DIN EN ISO 787-9 approx. 6 7 7Sieve residue [%] 1 DIN 53 195 < 0.02 < 0.02 < 0.004Hardness (Mohs) approx. 3 3 3Relative scattering power 3 DIN 53 165 > 50 > 50 > 52Lightness L* ISO 7724 approx. 98 98 98Refractive index 2.37 2.37 2.37Dispersibility satisfactory good very goodLight fastness good good goodWeathering resistance satisfactory* satisfactory* satisfactory*1) Mesh gauge 45 μm 2) Measured by means of sedimentation 3) Reference pigment: Standard TiO 2= 100* in combination with TiO 2good weathering resistance possibleNotes for processingSACHTOLITH HD-S can be dispersed in the Cow-les dissolver to grindometer finenesses of lessthan 20 µm at high speeds within 15 to20 minutes; additional dispersion on the roll millor in a pearl mill is recommendable in the case ofSACHTOLITH L and SACHTOLITH HD.Health and SafetySACHTOLITH is practically free of toxic heavymetals and therefore fulfills the recommendationsof the German BfR Recommendation IXfor pigments, as well as a large range of othernational purity specifications.4

Applications of SACHTOLITHGeneralIts low binder requirement combined with itsgood rheological and white-pigment propertiesenable SACHTOLITH to be used costeffectivelyand with technical benefits whereverorganic and inorganic binders need tobe highly pigmented for specific applications,such as in undercoat lacquers, jointing andsealing compounds, primers, etc. and also inputties, mastics and marking paints.Emulsion paints and dispersionplastersCombined with titanium dioxide-pigmentedemulsion paints and dispersion plasters,SACHTOLITH can improve rheological performanceand thus provide better conditions for application.Combination with UV-absorbing pigments,such as TiO 2or iron oxide pigments is the preconditionfor the use of SACHTOLITH in weatheringresistantpaint and coating systems.In many cases SACHTOLITH used in emulsionpaints and dispersion plasters shows a positivecontribution to keep surfaces white over a longperiod of time.SACHTOLITH has proven to be stable againstflocculation and to offer favorable flow performancein a large number of paint and coatingsystems. SACHTOLITH also exhibits a remarkablystabilizing effect when combined with coloredpigments, producing positive effects in the formof only slight flotation and flooding.5

Printing inksThe color neutrality achievable with SACHTOLITHis highly esteemed in printing inks. The pigment‘slow abrasiveness reduces wear on the dies andmatrices used for printing and increases life timeof the doctor blade.UV cured paint systemsThe photoinitiators used for the curing of pig-mented UV paint systems generally absorb lightin the wavelength range in which covering whitepigments, and titanium dioxide in particular, alsoabsorb light to such an extent that adequatecross-linking cannot occur. SACHTOLITH, a zincsulfide pigment, the absorption edge of which issignificantly shifted into the short-wave range,is an exception. Sufficient UV radiation for theachievement of photoinitiator action and forcomplete curing thus remains available:The curing of white UV-coatings pigmented withSACHTOLITH is easier, faster and complete – evenat higher film thickness.This leads to lower energy consumption duringUV-Curing and better results concerning mechan-ics and adhesion of the film. On the other handeconomics increase as SACHTOLITH replaces acertain resin share without increased resin de-mand and the content of photo initiator can bereduced by up to 20%.System:SACHTOLITH and TiO 2-Rutil: absorptionLaromer PE 44 FLaromer PO 83 F (PE Acrylates)SACHTOLITHTiO 2-RutilePowder coating systemsSACHTOLITH can also be used to advantage inSACHTOLITH can also be used to advantage inpowder-coating systems, since complete UVpowder-coatingsystems, since complete UVcuringis especially a problem when applying highcuring is especially a problem when applying highfilm thicknesses. Additionally SACHTOLITH canfilm thicknesses. Additionally SACHTOLITH canimprove rheological properties in powder coatingsand enhances flow and throughput. The pigment‘scolor neutrality permits its use in all tints.ZnSExample of ZnS inUV curing systemsTiO 2-Rutile6

04.009.03.09.e Sachtleben übernimmt keinerlei Gewähr für Genauigkeit, Aktualität, Korrektheit, Vollständigkeit, Qualität oder Brauchbarkeit der bereitgestellten Informationen.Jegliche Haftungsansprüche im Zusammenhang mit diesen Informationen sind ausgeschlossen.Great Solutions with Small ParticlesSachtleben Chemie GmbHA company ofHoldings, Inc.P.O. Box 17 04 54 • D-47184 Duisburg / GermanyPhone +49 2066 22-2615 • Fax +49 2066 22-3615E-Mail: coatings@sachtleben.com • www.sachtleben.com