Injection Color or Spray Coating: Which Should You Choose?
The two routes to a colored pack look similar on a sample and behave very differently in cost, durability and minimum quantity.
There are two common ways to get a colored component: color the material before it is molded, or spray the surface after. On a finished sample they can look close. In a project they are not close at all.
Injection color
The colorant goes into the resin, so the color runs through the whole part. A scratch does not show a different color underneath, which matters on closures and anything handled daily.
The constraint is the machine changeover. Changing color means purging the machine, so the minimum quantity is set by the production run, not by your order. Small quantities in a custom injection color are usually the expensive route.
Spray coating
Color is applied to the surface after molding. This gives access to finishes that injection cannot produce — soft touch, gradient, metallic effects — and it allows smaller quantities, because coating is a separate operation from molding.
The trade-offs are durability and cost per unit. A coated surface can wear at contact points, and the coating step adds labour per piece. Adhesion depends on the substrate, so the same coating does not perform identically on PP and PET.
How to decide
If the part is handled constantly and the quantity supports a run, injection color is usually the better answer. If the finish itself is the point, or the quantity is modest, coating is. If the pack has both a body and a closure, they do not have to use the same route — matching a coated bottle to an injection-colored cap is common, and the color match between the two is where the approval standard needs to be agreed in advance.
Whichever route you take, agree the color standard on a physical reference before production. A screen value is not a color standard.
