Packaging Materials & Processes Flashcards
7 cards from real CPT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Packaging Materials & Processes flashcards as text
Which biopolymer is derived from fermentation of corn starch and is commonly used in compostable packaging films?
Answer: Polylactic acid (PLA)
PLA is produced by fermenting corn starch to lactic acid, which is then polymerized into a compostable thermoplastic used in films and rigid containers.
In flexographic printing, the anilox roll serves what function?
Answer: Meters a controlled volume of ink to the printing plate
The anilox roll has an engraved cell pattern that picks up ink from the fountain and delivers a precise, metered amount to the printing plate.
What is the significance of the 'glass transition temperature' (Tg) in packaging material selection?
Answer: The temperature below which an amorphous polymer becomes brittle
Below Tg, amorphous polymers lose segmental mobility and become rigid and brittle, which is critical for cold-chain packaging applications.
Which end-use application would most benefit from using Surlyn (ionomer resin) as a packaging film layer?
Answer: Seal-through contamination at the heat seal
Ionomers like Surlyn can heat seal through grease, oil, and food contamination, making them ideal for fatty food packaging where seal contamination is a risk.
In the manufacture of paperboard, what is the purpose of the 'sizing' treatment applied to the furnish or paper surface?
Answer: To control water penetration and ink absorption
Sizing (using rosin, AKD, or ASA agents) controls the hydrophobicity of paper, limiting water penetration and managing ink spread during printing.
What does the term 'coefficient of friction' (COF) refer to in flexible packaging, and why does it matter?
Answer: The resistance to sliding between film surfaces, affecting machinability
COF measures how easily film slides against itself or metal surfaces; too high a COF causes jams on form-fill-seal equipment, while too low causes registration problems.
Which seaming defect in two-piece metal cans results from insufficient seaming chuck pressure during the first seaming operation?
Answer: Vee (V-shaped) seam
A V-shaped (Vee) seam defect results when the first seaming roll does not adequately curl the cover hook under insufficient chuck support, leaving an unfurled V-profile.