Decorating, Printing, and Coloration
Molded or fabricated parts may require decorating, printing, or coloration to complete the finished product. Many molded parts often require decorative treatments or printing as part of the function of the article.
The use of decorating techniques allows for added functionality and enhanced appearance of parts. Polymers are responsive to a number of decorating techniques, including (but not limited to) painting, overmolding, printing, and the use of decals and labels. When designing parts for assembly and/or decoration, it is vital that informed decisions be made regarding joining or decorating techniques used to ensure that the final article maintains its inherent properties.
Printing is a commonly employed method for application of designs, characters, or other markings on parts using conventional printing equipment. Unlike materials which require a secondary process, such as flame or corona treatment to enhance ink adhesion, Eastman polymers have shown to print well in the as-molded state.
Numerous types of paints and inks are available; however, not all of them behave the same. Some solvents used in inks and paints can chemically attack the plastic. And some types of colorants and pigments used in paints and inks can form a brittle coating on the polymer material which can adversely affect the toughness and durability of the finished parts. Polyurethane-based inks and paints that exhibit flexibility after curing perform best in conjunction with Eastman polymers. It is important that the appropriate ink systems be used to produce parts with high quality graphics.
Polymers can be tinted with transparent and opaque colorants. It is suggested that you use a color masterbatch, if available, versus using a fully compounded color product as a color masterbatch can be mixed at a precise loading into a clear, base polymer. The color masterbatch will then distribute and homogenize into the base material during the plastication/extrusion process. If needed, an external mixing nozzle may be used to further mix the colorant into the melt. Mixing sections on the screw are typically not recommended as they can impart excessive shear heating of the melt and can have hang-up points where the polymer may stick on the screw and degrade.