Study 2 Peeling Labels

Adhesive labels are used on many products and need to remain on the product for many reasons including safety, identity and proper use of the product. In this case the adhesion failed and prevented the further use of the equipment in which the product was used. 

Batteries are typically produced with deep drawn metal cans on which a pressure sensitive adhesive label is applied for product identification, branding and safety information. Customers began complaining of batteries becoming jammed in various types of equipment. Devices returned to the manufacturer showed that the pressure sensitive labels had peeled back, resulting in adhesion between the overturned label and the device. Further examination of batteries on store shelves for more than a year also indicated peeling labels in a low frequency of batteries. These labels consisted of laminates of paper and polyester. The labels are normally flat and stiff and when applied over a battery, the labels will return to the flat condition if the adhesive fails. This results in peel-back at the edges of the label. 

Investigation into the battery processing was initiated. Comparative GC/MS analysis of peeling and non-peeling areas of the labels indicated that the peeling areas contained phthalates and palmitic acid. Both act as plasticizers in the pressure sensitive adhesive used for these labels. Since the labels are printed in a continuous process, it was unlikely that only specific areas would be affected. This was consistent with the observed low frequency of label peeling, and eliminated the deposition of adhesive as a potential root cause. 

Handbook for the Chemical Analysis of Plastic and Polymer Additives 

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Electron microscopy was used to provide more details on the nature of the coke deposits as well as their location. HRSEM reveals the HS-FER crystallites to be platelets, typically 250 nm in size, with a mean thickness of only 20 nm. For a spent HS-FER containing 9.1 %w of coke TEM photographs are displayed in Fig. 7. Careful inspection of the FER platelets reveals that they are bordered by a layer of amorphous material (labelled) which is probably coke. Also at the edge of the platelets there are layers of similar width (picture corresponds to a view down the (100) surfaces as determined by a selected area diffraction study). This suggests that all the external surfaces, both porous and non-porous, contain a layer of coke. To confirm that the amorphous layers indeed consist of carbonaceous material, PEELS spectra were collected which closely resemble that of the amorphous carbon film supporting the sample crystallites. With samples containing less carbon (below 7 %w), TEM does not reveal a coke layer at the surface of the crystallites, but rather reveals discrete coke clusters of 1.0-1.5 run. 

The extraction of natural nootkatone from citrus oil and peel is too expensive, because the process is characterized by low yields and high biomass production, and it suffers from annual harvest fluctuations. The chemical oxidation of the sesquiterpene valencene extracted from orange peels often results in off-notes, and it has the disadvantage of employing heavy-metal salts as strong oxidants thus the final product cannot be labeled as natural. Therefore, biotechnological routes have been extensively studied in the last decade to find an economical and sustainable synthetic procedure to natural nootkatone. Most of them make use... 

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