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SACHTOLITH – White pigment for

a wide range of coating applications

1

SACHTOLITH – the white pigment

based on pure Zinksulfide. Designed

to offer solutions for a wide range of

applications.

Because of its special properties like

Moh’s hardness, UV-absorption edge

and low specific surface area. These

particles provide benefits to many ap-

plications.

Great Solutions with Small Particles

2

SACHTOLITH

The product

SACHTOLITH (CAS Registration No. 1314-98-3) SACHTOLITH (CAS Registration No. 1314-98-3)

is a white pigment consisting of extremely pure is a white pigment consisting of extremely pure

zinc sulfide. Highly purified zinc salt and sodium zinc sulfide. Highly purified zinc salt and sodium

sulfide solutions, from which all discolorant and sulfide solutions, from which all discolorant and

toxic heavy metals have been removed down to metals have been removed down to

ppm trace levels, are used for its production. are used for its production.

The extremely finely precipitated zinc sulfide is The extremely finely precipitated zinc sulfide is

adjusted to the narrow particle-size distribution adjusted to the narrow particle-size distribution

of approx. 0.3 μm which is optimum for scatterof approx. 0.3 μm which is optimum for scatter-

ing of light by means of calcining at arounding of light by means of calcining at around

700° C. Three SACHTOLITH grades are produced: 700° C. Three SACHTOLITH grades are produced:

L, HD and HD-S.

The SACHTOLITH grades

SACHTOLITH L is the standard grade, with no

organic treatment. SACHTOLITH HD and HD-S

contain small amounts of organic wetting agents

to improve wettability and dispersibility in aque-

ous and organic media. Thanks to its high-energy

grinding process (micronization) and a special

screening process, SACHTOLITH HD-S is free of

coarse particles and is easily dispersed. Its optical

performance is some 10 to 15 % superior to that

of the L and HD grades.

3

SACHTOLITH is registered and approved for use in a large range of countries; the fol-lowing are intended only as examples: Germany:

BfR: Meets limits

VwVwS:

Not a water pollutant

EU:

AP 89 (1) and AP 96 (5) Ref. No. 96320

EN 71/3

Hazardous Substances Ordinance:

Not a hazardous in EEC 67/548 ff.

Japan:

MITI 1-572

USA:

FDA § 178.3297

TSCA 1314-98-3

Clean Air Act Amendments: Not listed

Hazardous Air Pollutants: Not an air pollutant

Properties of SACHTOLITH

Chemical

In the >4 pH range, SACHTOLITH is resistant to

practically all chemicals. Its solubility in 0.1 m

hydrochloric acid is approx. 0.3 %.

SACHTOLITH can be oxidized to ZnSO4 by power-

ful oxidizing agents or by UV radiation in the

presence of water and oxygen. ZnS is capable of

reacting superficially with additives which contain

heavy metals, particularly at high processing tem-

peratures and under exposure to UV radiation.

The property of fixing undesirable heavy-metal

ions can, on the other hand, prevent catalytic

cracking of polymers. Unlike TiO2, ZnS does not

generate any colored complexes with phenolic

anti-oxidants, and reduces the catalytic oxidation

of polymers. SACHTOLITH also remains stable up

to at least 350° C under exposure to air oxygen.

Physical

SACHTOLITH consists primarily of polycrystalline

wurtzite and is an n-type photo semiconductor,

like the TiO2 pigments. Under normal conditions,

SACHTOLITH is a good isolator (erel

approx. 8). At

approx. 27 W m-1 K-1, its thermal conductivity is

unusually high for a mineral product, its specific

heat, on the other hand, extremely low, at some

500 J kg-1 K-1.

Specific surface area and binder requirement are

low and permit good rheological properties even

at high pigmentation levels. In combination with

the pigment‘s low UV absorption, its good light

reflectance in the visible range produces a neutral

white tone and results in optimum effective-

ness of optical brighteners, Day-Glow paints and

photoinitiators.

Due to the product‘s lower refractive index (2.37)

compared to TiO2, its scattering power is lower

than that of rutile by 35 % and than that of ana-

tase by 25 %. Its spherical particle geometry and

low Mohs hardness of 3 mean that SACHTOLITH

causes no abrasion or wear on metallic materials.

Toxicological

SACHTOLITH is a practically insoluble inorganic

substance containing no harmful or notifiable

constituents. Under correct use, it is non-toxic

and is suitable, inter alia, for the pigmentation

of toys and foodstuffs packaging materials.

4

Health and Safety

SACHTOLITH is practically free of toxic heavy

metals and therefore fulfills the recommenda-

tions of the German BfR Recommendation IX

for pigments, as well as a large range of other

national purity specifications.

Technical Data of SACHTOLITH

Notes for processingNotes for processing

SACHTOLITH HD-S can be dispersed in the CowSACHTOLITH HD-S can be dispersed in the Cow-

les dissolver to grindometer finenesses of less les dissolver to grindometer finenesses of less

than 20 µm at high speeds within 15 to than 20 µm at high speeds within 15 to

20 minutes; additional dispersion on the roll mill 20 minutes; additional dispersion on the roll mill

or in a pearl mill is recommendable in the case of or in a pearl mill is recommendable in the case of

SACHTOLITH L and SACHTOLITH HD.SACHTOLITH L and SACHTOLITH HD.

SACHTOLITH L HD HD-S

ZnS [%] approx. 98 98 98

Volatile constituents (105° C) [%] DIN EN ISO 787-2 approx. 0.2 0.2 0.2

pH DIN EN ISO 787-9 approx. 6 7 7

Sieve residue [%]1 DIN 53 195 < 0.02 < 0.02 < 0.004

Hardness (Mohs) approx. 3 3 3

Relative scattering power3 DIN 53 165 > 50 > 50 > 52

Lightness L* ISO 7724 approx. 98 98 98

Refractive index 2.37 2.37 2.37

Dispersibility satisfactory good very good

Light fastness good good good

Weathering resistance satisfactory* satisfactory* satisfactory*

1) Mesh gauge 45 μm 2) Measured by means of sedimentation 3) Reference pigment: Standard TiO2 = 100

* in combination with TiO2 good weathering resistance possible

5

Emulsion paints and dispersion plasters

Combined with titanium dioxide-pigmen-

ted emulsion paints and dispersion plasters,

SACHTOLITH can improve rheological performance

and thus provide better conditions for applica-

tion. Combination with UV-absorbing pigments,

such as TiO2 or iron oxide pigments is the precon-

dition for the use of SACHTOLITH in weathering-

resistant paint and coating systems.

In many cases SACHTOLITH used in emulsion

paints and dispersion plasters shows a positive

contribution to keep surfaces white over a long

period of time.

SACHTOLITH has proven to be stable against

flocculation and to offer favorable flow perform-

ance in a large number of paint and coating

systems. SACHTOLITH also exhibits a remarkably

stabilizing effect when combined with colored

pigments, producing positive effects in the form

of only slight flotation and flooding.

Applications of SACHTOLITH

General

Its low binder requirement combined with its

good rheological and white-pigment proper-

ties enable SACHTOLITH to be used cost-

effectively and with technical benefits wher-

ever organic and inorganic binders need to

be highly pigmented for specific applications,

such as in undercoat lacquers, jointing and

sealing compounds, primers, etc. and also in

putties, mastics and marking paints.

6

SACHTOLITH and TiO2-Rutil: absorption

SACHTOLITH

TiO2-Rutile

Printing inks

The color neutrality achievable with SACHTOLITH The color neutrality achievable with SACHTOLITH

is highly esteemed in printing inks. The pigment‘s is highly esteemed in printing inks. The pigment‘s

low abrasiveness reduces wear on the dies and low abrasiveness reduces wear on the dies and

matrices used for printing and increases life time matrices used for printing and increases life time

of the doctor blade.

UV cured paint systemsUV cured paint systems

The photoinitiators used for the curing of pigThe photoinitiators used for the curing of pig-

mented UV paint systems generally absorb light mented UV paint systems generally absorb light

in the wavelength range in which covering white in the wavelength range in which covering white

pigments, and titanium dioxide in particular, also pigments, and titanium dioxide in particular, also

absorb light to such an extent that adequate absorb light to such an extent that adequate

cross-linking cannot occur. SACHTOLITH, a zinc cross-linking cannot occur. SACHTOLITH, a zinc

sulfide pigment, the absorption edge of which is sulfide pigment, the absorption edge of which is

significantly shifted into the short-wave range, significantly shifted into the short-wave range,

is an exception. Sufficient UV radiation for the is an exception. Sufficient UV radiation for the

achievement of photoinitiator action and for achievement of photoinitiator action and for

complete curing thus remains available:complete curing thus remains available:

The curing of white UV-coatings pigmented with The curing of white UV-coatings pigmented with

SACHTOLITH is easier, faster and complete – even SACHTOLITH is easier, faster and complete – even

at higher film thickness.

This leads to lower energy consumption during This leads to lower energy consumption during

UV-Curing and better results concerning mechanUV-Curing and better results concerning mechan-

ics and adhesion of the film. On the other hand ics and adhesion of the film. On the other hand

economics increase as SACHTOLITH replaces a economics increase as SACHTOLITH replaces a

certain resin share without increased resin decertain resin share without increased resin de-

mand and the content of photo initiator can be mand and the content of photo initiator can be

reduced by up to 20%.

System:

Laromer PE 44 F

Laromer PO 83 F (PE Acrylates)

Example of ZnS in

UV curing systems

ZnS TiO2-Rutile

Powder coating systemsPowder coating systems

SACHTOLITH can also be used to advantage in SACHTOLITH can also be used to advantage in

powder-coating systems, since complete UV-powder-coating systems, since complete UV-

curing is especially a problem when applying high curing is especially a problem when applying high

film thicknesses. Additionally SACHTOLITH can film thicknesses. Additionally SACHTOLITH can

improve rheological properties in powder coat-

ings and enhances flow and throughput. The pig-

ment‘s color neutrality permits its use in all tints.

Great Solutions with Small Particles

04

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.

Sachtleben Chemie GmbH A company of Holdings, Inc. P.O. Box 17 04 54 • D-47184 Duisburg / Germany Phone +49 2066 22-2615 • Fax +49 2066 22-3615 E-Mail: coatings@sachtleben.com • www.sachtleben.com