Pressure Sensitive Papers & Films
Pressure sensitive materials consist of a face stock and a liner stock. The face stock is literally the label material. The liner is a release material that the label is married to. The adhesive is applied to the back of the face stock and then the face stock is married to the liner. The liner has a release coating typically silicon that will allow the face stock to be removed cleanly. Face materials are typically paper or poly films depending on the labeling end-use requirements. The poly films are often clear or printed and can be metalized as well. Face materials can be over laminated or coated with UV coatings to protect the image.
Instant Redeemable Coupon Material
Instant Redeemable coupon materials, often referred to as IRC films, are most often used in conjunction with instant redeemable coupons in a retail environment. An IRC film has 4 levels of material. Paper (the coupon), a 2-ply clear Poly film, and a liner. When the label is applied to a product at the point of sale the entire structure is applied “intact”. When a consumer pulls the IRC label at the point of sale the 2-ply film separates and the consumer has a coupon with no adhesive, the adhesive and the 1st layer of the 2-ply film stay on the package.
Paper/Poly/Foil/Poly is a common structure used in conjunction with the creation of flexible packaging. The paper is printed on the surface and married to the other 3 materials. Once the structure is created it is supplied in a roll form to a filler or converter that will form a standup or layflat pouch from the materials. The reason this structure is used to prevent oxygen or moisture from reaching the product once it is enclosed in the packaging. The foil is the barrier that prevents oxygen and moisture from penetrating the product.
Poly/Poly/Foil/Poly structures are used for the same barrier applications as the Paper/Poly/Foil/Poly structures. The main reason for the poly face materials is to protect the image from degradation. Typically the first level of poly is printed on the underneath or the backside in reverse. After it is printed it is married to the other levels to complete the structure. Once the image is complete the image cannot be scratched or damaged because it is underneath the poly film.
Polypropylene film is used in flexible packaging as the sealant layer in a multi-layered structure. It can also be used as a single a layer film as well. Often it is surface printed or blank and provided in rolls to converters and fillers as a single layer substrate. The product is used on vertical or horizontal filling machines to create fin seal or lapp sealed packages.
Polyester & Polyethylene
Polyester and Polyethylene films are used in all kinds of flexible packaging, from barrier film components like Poly/Poly/ Foil/Poly constructions to shrink sleeve applications. Polyester comes in a number of formats clear, white, metalized, heat seal and NO seal. Polyethylene comes in Clear, White, HDPE, MDPE, LDPE, LLDPE, ULLDPE, and Co-Extruded Blends
Nylon films are available as Clear, Bi-Axially Oriented, Machine Oriented, and Cast. The Bi-Axially and oriented terminology refers to the materials “grain” direction. Films can be designed to alter their behavior under manufacturing conditions. How much will a film stretch or shrink or what direction a film will tend to shrink? Nylon can be used in conjunction will other films to help control their reaction to stretch and shrink as a combined structure.