Blackplate for packaging

Blackplate is low carbon mild steel, not tincoated and normally not oil or otherwise treated. In other words, after the final cold rolling treatment – whether temper rolling or double reduction or no further treatment is given to it.

Blackplate can be used for container manufacture, using the techniques of welding or cementing for the production of the sod seam. Both its surface have to be protected by applying synthetic lacquer, otherwise rusting easily occurs.

Blackplate is no longer black. When new and clean, it is almost indistinguishable from tin plate to a passing observer.

It is called blackplate because in the days when it was rolled by hand, it acquiring a thin coating of black oxide which was left on the surface and not dissolved away in acid.

Blackplate is not used widely because of its tendency to rust rapidly, its spoor chemical resistance and its poor reflectivity, which creates decoration difficulties.
Blackplate for packaging

Innovation of cans

Appert canning technique was improved by the work of British scientists Bryan Donkin and John Hall. They created the first tinned canned food in 1812.

The first cans were handmade of steel coated with tin. Durand’s early process produced 10 cans per day; modern can-making machines can produce 1000 or more per minutes.

Other innovations include quick-opening cans with pull tabs, as are used for soft drinks, sardines and nuts; cans that are opened with a slotted key that comes with the can, as are used for sardines and cured hams; pasteurized cans that use a propellant to dispense whipped cream and cheese spreads; and extruded or drawn cans, as are used for soft drinks, tuna and sardines.

The extruded cans has several advantages over the conventional can, a major one being the elimination of the bottom and side seams, which reduces the probability of seam failures eliminates the use of lead, (used in side seam) and permits more stable stacking in shelves, requiring somewhat less vertical space.

Two basic types of allowed metals are used in food packaging: steel and aluminium. Steel is used primarily to make rigid cans, where aluminium is used to make cans as well as thin aluminium foils and coatings.

Until a few years ago nearly all steel used for cans was coated with a thin layer of tin to inhibit corrosion; hence, the name ‘tin can’.
Innovation of cans