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Special Report

The Sustainable Facts about Metalized Decorating Techniques

by Jeff Peterson, Executive Director, FSEA and David Hutchison, CEO/Managing Member, BrightMARKS, LLC

August-September, 2010
Recent presentations and editorials in the press on sustainable packaging have been very quick to assemble all metalized decorating techniques into one category. In addition, it seems that there are many who want to conclude that all metalized effects are non-sustainable and always an environmentally unfriendly choice for brand managers and packaging designers.

The interest in sustainability and global ecological impact has ignited a great deal of communication among brand owners and product manufacturers about the viability of metallic effects. With this, it also has created misconceptions and confusion over the different choices available within the family of metallic decorating options.

There are several different types of metalized decorating processes and several ways to apply a metalized surface to board or paper. Following is a short description of each of these options and information pertaining to the sustainability of each process.

Aluminum Foil Board Laminates
Foil board laminates were among the first type of processes for creating a metallic look on paperboard. This product is produced by physically laminating with an adhesive a sheet of aluminum to a sheet of paper. The aluminum and paper materials to produce the sheet could be sourced from renewable or recycled product. The manufacturing process is very efficient, however there are relatively few companies involved in the production of aluminum foil board globally. The finished product would not be considered recyclable or compostable, and is sustainably heavier per square inch than other metallic decorating alternatives.

Metalized Film Laminated Boards
Film laminated boards typically use oil-based films as a central raw material. The customary films used are Oriented Polypropylene (OPP) or Polyester (PET). There have been developments over the last several years using cellulose-based film laminated board. The product is produced by metalizing the film of choice and laminating the metalized film to the paperboard with an adhesive. The clarity of the film used to create the product is normally not from recycled grade materials. The aluminum used in the metalizing process is normally from recycled grade materials. The paper board can be from renewable or recycled grade sources. The laminating process is more involved than that of aluminum foil board but is very efficient. There are relatively few companies producing film laminated metalized boards. Oil-based film products are not considered recyclable or compostable by any published standards. However a cellulose film product is considered recyclable and compostable. Both options are lighter than an aluminum foil board but heavier than other metallic decorating options.

Transfer Metalized Boards and Papers
Transfer metalized film is produced to create a metalized surface on thinner caliper papers and when weight reduction in an application is desired. The manufacturing process has similarities to cold foil transfer processes, but on a larger high-volume scale. A film is coated and metalized to allow the layer of aluminum metalizing to be released away. This metalized film is placed in contact with a paper or paperboard that has an adhesive applied to it. The adhesive can be applied in a flood manner, covering all of the sheet, or a discrete manner, allowing selective elements to transfer. The paper and the film is then stripped away releasing the metallic aluminum, which remains on the sheet only where the adhesive has been applied. The film used in the process can be reused and can be produced from recycled sources. The aluminum used in the process is from recycled sources. The paper and paperboards can be from renewable and/or recycled sources as well. This type of metalized process is considered recyclable and compostable by many published standards. The finished product is among the lightest weight options for metallic finishes and therefore, is a more sustainable option as well.

Direct Metalized Boards and Papers
Direct metalized boards and papers are typically produced using vacuum metallization which deposits a very thin vapor of aluminum directly onto the substrate. The resulting aluminum layer will take on the attributes of the paper fibers or surface profile. Very smooth papers will provide higher reflectivity than less smooth papers. Direct metalized papers and boards are most commonly coated with a clear coating. The coating will provide attributes for printing, exposure resistance features and final finish to the paper. The coatings can be cellulose-based or acrylic-based. Application methods will cure using oxidation, ultraviolet light or electron beam. The paper and paperboard can be from renewable and/or recycled sources. The aluminum is from recycled sources. The coatings are typically not from sources considered renewable or recyclable. This metalized option is considered recyclable and compostable by many published sources. It also is a more sustainable choice from the standpoint of being one of the lightest weight options.

Metallic Inks and Coatings
Two types of technology are widely used to produce metallic inks and coatings. Of the two, the oldest technology dates back several decades and has traditionally been referred to as metallic powder technology. The finished results of products using metallic powder suffered from a number of shortcomings. Reflectivity and brilliance was dull at best and resistance levels to in-use exposures were often a risk. The latest technology for metallic inks and coatings is referred to as metal platelet technology. Metal platelet technology has significantly overcome the shortcomings of the metal powder technology.

The sourced materials for metal platelet products are very similar to the materials used in other metallic effects technologies. Most metal platelet products begin with a vacuum metalized film, typically polyester. This metalized film is coated with separation coatings and vacuum metalization several times. This builds up the amount of aluminum on the film necessary to achieve the reflectivity and brilliance of the finished product. The film is not generally from recycled sources but can be reused several times, the separation products can be from renewable organic sources or may be synthetic and the aluminum is from recycled sources. This metalized film is then put through a wash to remove the very thin coats of aluminum During the washing process, the aluminum layers break up, forming very fine platelets. These platelets are then introduced to a resin or wax to create the base that is used for an ink or coating. Colorants, slip agents, aligomers, oxidizers or photo initiators are added to complete the preparation of the material for the application method on press. To get to the final deliverable product using metallic inks or coatings is a three-stage process. Stage one is the manufacture of the metallic source film, stage two is the manufacture of the ink or coating mix and stage three is the application of the ink or coating mix to the paper or board. This type of product is marketed as recyclable and as a sustainable option over other metallic choices. However, the three-stage manufacturing process of metal platelet technology creates a carbon footprint that is thought to be larger than other metallic decorating options.

Cold Foils
Cold foil technology used to create metallic effects has grown dramatically both in brand owner use and in technical development. The process is similar to that of transfer metalizing described earlier, with the exception that the application of the metal effect is typically performed at the same time that the print graphic elements are applied to the sheet. A roll of polyester film that has been coated with a separation coating, a surface protection coating and a vacuum metalized coating provides the metallic effects that will be applied to the sheet. This film is placed in contact with the paper between printing stations following the application of an adhesive. The metallic coatings from the film will only transfer to the paper where the adhesive has been applied. The adhesive is cured to set the metallic effect with permanence to the sheet so that additional colors of ink can be applied directly to the metallic surface. Under proper conditions this method of creating a metallic effect can produce a broad range of reflective areas, from large solids to very fine details.

The film that carries the metallic coatings through the process is wound into a roll. This roll has a number of prospective uses: it can be used as an energy source, repurposed to make other metallic products (such as textiles) or recycled where technology is available to do so. Products produced with cold foil technology are considered both recyclable and compostable by several published standards, a fact that has independent third-party verification. It also is one of the lightest metallic finishing options.

Hot Stamping Foils
Hot stamping foil applications are among the oldest known methods of creating a metallic finish and among the most advanced in technical development. The metallic finish is created by transferring very thin coatings of color and aluminum to the paper or board using heat and pressure. The heat activates separation coatings and adhesive coatings that affect the permanence of the resulting finish on the paper or board. The process is typically performed after the print graphic elements are applied to the sheet, but can be performed prior to the printing if the application equipment has suitable precision. Under proper conditions this method of creating a metallic effect can produce a broad range of reflective areas, from large solids to very fine details.

A roll of polyester film that has been coated with a separation coating, a surface protection coating, a vacuum metalized coating and an adhesive coating provides the metallic effects that will be applied to the sheet. This film is placed in contact with the paper by a heated metal die. The die serves to define the amount of area that will transfer from the film to the paper or board. The adhesive is thermally activated and cured as it cools to set the metallic effect with permanence to the sheet so that additional processing can take place.

The film that carries the metallic coatings through the process is wound into a roll as with cold foil applications. As with cold foil film, this roll has a number of prospective uses or it can be recycled where technology is available to do so. Products produced with hot stamping foil are considered both recyclable and compostable by many published standards, which also has been verified by an independent third party. It also is one of the lightest weight options with metallic finishes.

See this table in pdf format summarizing the attributes and sustainability aspects of each type of metallic decorating technology.

As described above, not all metalized decorating processes should be categorized together. There are aspects of all types of metalized decorating technologies that should be considered carefully before a final choice is made on the best option, especially when the sustainability of the process is in question.

Providing brand managers and the graphic design community with the facts is the best way to eliminate the misconceptions in the marketplace.

The Foil & Specialty Effects Association (FSEA) has recently published a report that confirms the recyclability and repulpability of foil-decorated paper and paperboard. A well respected, third-party research firm, Pira International in Surrey, UK, performed the study. The study validates the recyclability of paper products decorated by both the hot stamp and cold foil processes. For more information or to receive a copy of the report, contact the FSEA at jeff@fsea.com or 785.271.5816.