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Paint and Printing Ink Driers
The Shepherd Chemical Company laid the groundwork and set
the standards for using metallic driers in Paints and Coatings
as well as Inks. No other drier company in the market today
can match our 85 years of knowledge and experience. Our ISO
Certification confirms that Shepherd Chemical conforms to
the highest industry standards.
Today Shepherd offers a wide variety of high-quality driers.
Metallic driers accelerate the drying of paints, coatings
and inks by catalyzing the oxidation of drying oils and synthetic
resin varnishes. Metal carboxylates (often referred to as
soaps) have long been used in the printing and paint industries
for their ability to dry through oxidation or polymerization
in solvent based coatings.
Cobalt (Co): Cobalt is “the Drier” metal. A strong
oxidative drier, it is the most widely used metal drier and
is often referred to as a “surface” or “top”
drier. Cobalt, when used alone, may cause wrinkling of some
coatings due to the fast surface cure. It is therefore regularly
used in conjunction with other metals to provide a more uniform
cure and a smooth finish.
Manganese (Mn); Used alone or as a co-drier with Cobalt,
Manganese is an active “through” drier that also
has oxidative drying properties. Through driers are so-named
due to their ability to catalyze cross-linking or polymerization
within a coating. Shepherd’s XL-Dri helps Manganese
work under poor drying conditions by chelating the Manganese
thereby increasing the available active metal. Manganese has
a dark color and is therefore a poor choice for light color
finishes.
Cerium (Ce): Cerium promotes cross-linking or polymerization
and can be used in place of other through driers. Cerium has
a low color and is a very active drier in most alkyd coating
formulations making it an ideal choice for baked finishes,
overprint varnishes and other applications where color is
critical.
Zirconium (Zr): Zirconium is a well established, efficient
supplemental drier generally used with Cobalt or Manganese
to promote drying of the undercoat. Zirconium came to the
forefront during the move to lead-free products and is still
used as a lead replacement
Calcium (Ca): Calcium has very little catalytic activity
when used alone and yet is the most widely used auxiliary
drier in the world. This is because when used in conjunction
with other metal driers Calcium has excellent drying properties.
Calcium promotes polymerization “through” drying
similar to lead when used in tandem with Cobalt. Like Zinc,
Calcium is a very good wetting and dispersing agent.
Starting Point Levels for Various Metal Driers
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Drier
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Loading Level Based on Vehicle Solids
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Cobalt
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0.01 – 0.1% Metal
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Manganese
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0.02 – 0.1% Metal
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Lead
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0.35 – 0.5% Metal
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Calcium
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0.1 – 0.3% Metal
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Zirconium
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0.1 – 0.3% Metal
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Cerium
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0.1 – 0.3% Metal
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Zinc
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0.1 – 0.15% Metal
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XL-Dri
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0.2 – 0.3 %
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Drier Calculations:
To calculate the quantity of various driers required for coatings
formulas you must know:
a.) Vehicle Solids
b.) Percentage of Metal Available in the Driers
c.) Required Percentage of Metal on Vehicle Solids
Required Drier Quantities can then be calculated using this
formula:
Drier Required (lbs) = Vehicle Solids (lbs) x [(% Metal Required)
_ (% Metal in Drier)]
Other metals offered by the Shepherd Chemical Company
which are used as driers:
Bismuth
Copper
Chromium
Lithium
Potassium
Nickel
Neodymium
Additives:
XL-Dri – Drier Accelerator (useful in high-solids coatings)
Skinno #2 – Anti-Skinning Agent
Cobalt 21
D-Spurse – Dispersing Agent
Water Reducible Driers:
XL-Dri
Shepherd’s “WR” & “WDX” Driers
Our Driers are labeled and sold in conjunction with Dura
Chemicals, Alameda, Calif.
Ink Driers:
Years ago driers formulated for the Ink Industry were designed
as Pastes to add viscosity and to reduce the content of volatile
solvents such as Mineral Spirits. Inkies have generally stayed
with Paste driers even though the need for driers to provide
rheological benefits has long since passed. Today many Ink
formulators, realizing there is an economic benefit (Liquid
driers are generally less expensive on a metal basis), are
switching to liquid driers,. Shepherd Chemical remains committed
to providing both Paste and Liquid Driers to the Ink Industry.
Shepherd Chemical introduced the Shepherd Draw-Down plate
nearly 50 years ago (before most of our competitors were even
in business!). We are pleased to offer a version of this plate
today, Ceramic Coated Steel with marked gradations on both
sides to measure flow/time. Please call our Customer Service
Department for cost and shipping details.
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