Feature Markets - Rigid Packaging

Rigid Metal Packaging Coating “Can Coating”

Metal containers for food and non-food applications – or simply said cans – are usually coated on both sides, exterior and interior. Exterior can coatings stand for protection against environmental influences like mechanical wear during transport or chemical attack causing rust. On top, decorative aspects play an important role as the can shall attract end users' attention on the shelf.
The striking need for interior can coatings is to protect the filling goods from the metal substrate and vice versa. Given the vast variety of canned goods such interior coatings ideally possess extremely high and broad chemical resistance and durability. Especially when it comes to packs for food & beverage health and safety aspects are of utmost importance. This is manifested for example by the commencing main stream to replace bisphenol-A (BPA) – a technically proven main building block of epoxy-binders used in most interior can coatings since decades. The reason is that traces of BPA migrating from the coating into the canned food are suspected to cause adverse health effects upon food consumption.
Evonik offers a versatile range of high quality products feasible for the formulation of can coatings. Next to their technically outstanding properties these coating raw materials can be used to create new can interior surfaces without the need for BPA. The following table is a quick shot on exemplary products for this application field:
Raw material type
Evonik product range
Typical uses
Main binder
DYNAPOL® – Polyesters
Stoving enamels for can coatings
 
DYNAPOL® L 912*
Interior protection enamels for cans
 
 DYNAPOL® LH 818-05
Exterior decorative stamping enamels for
cans, caps and closures
 
DYNAPOL® LH 823-01*
Exterior decorative enamels for tubes and aerosol cans
 
DYNAPOL® LH 775-52*
Clear overprint varnishes
 
DYNAPOL® L 490*
Adhesion promoter for caps and closures
Crosslinker
VESTANAT® B – Blocked polyisocyanates
Stoving enamels for polyurethane can coatings
 
VESTANAT® EP-B 1186 A*
Exterior and interior food contact can
coatings
 
 VESTANAT® B 1358
Exterior can coatings
 Co-binder
TEGO® AddBond – Adhesion resins
Can coatings
 
TEGO® AddBond LTW
Metal adhesion promotor
 Additives
ACEMATT® – Silica
Can coatings
 
ACEMATT® 810 (precipitated untreated coarse grained silica)
Highly matted can coatings
 Monomers
VISIOMER® – Specialty methacrylates
Building blocks for poly(meth)acrylates 
 
VISIOMER® EHMA VISIOMER® HEMA
VISIOMER® HPMA
VISIOMER® GMAA
Specialty monomers for composition of waterborne binders, e.g. for food or beverage can coatings
* Active substance is compliant with food contact regulation FDA 21 CFR § 175.300.
 
For more details you're kindly invited to visit our product group homepages. Evonik Technical Service experts can support you to optimize your paint formula by recommendations, lab work or joint development projects.