CPE Packaging Materials & Components 4 — Questions and Answers
Question 1: Which test method is commonly used to evaluate the seal strength of flexible packaging heat seals?
- Elmendorf tear test
- T-peel or lap shear test (Correct answer)
- Puncture resistance test
- Gelbo flex test
Correct answer: T-peel or lap shear test
T-peel and lap shear tests measure the force required to separate heat-sealed flexible film bonds under controlled conditions.
Question 2: What is the function of a desiccant in pharmaceutical packaging?
- To absorb oxygen from the headspace
- To absorb moisture to protect moisture-sensitive products (Correct answer)
- To release carbon dioxide as a preservative
- To maintain consistent internal pressure
Correct answer: To absorb moisture to protect moisture-sensitive products
Desiccants such as silica gel or molecular sieves absorb moisture within the package to protect products sensitive to humidity degradation.
Question 3: In blow molding of plastic containers, what is 'parison' programming used for?
- Controlling the mold temperature profile
- Varying parison wall thickness along its length to control bottle wall distribution (Correct answer)
- Programming the blow ratio
- Setting the cooling cycle duration
Correct answer: Varying parison wall thickness along its length to control bottle wall distribution
Parison programming adjusts the die gap during extrusion to create a variable-thickness parison, compensating for uneven stretch during blowing.
Question 4: Which packaging component is most often used to provide tamper evidence on a plastic bottle closure?
- Induction seal liner
- Break-away band (pilfer-proof band) (Correct answer)
- Cork insert
- Pressure-sensitive liner
Correct answer: Break-away band (pilfer-proof band)
A break-away band attached to the cap base fractures or separates when the cap is first opened, providing visual tamper evidence.
Question 5: What characteristic distinguishes biaxially oriented polypropylene (BOPP) from cast polypropylene (CPP) film?
- BOPP has lower clarity than CPP
- BOPP has higher stiffness and better barrier due to orientation in two directions (Correct answer)
- CPP has higher tensile strength than BOPP
- BOPP is heat sealable without coatings; CPP is not
Correct answer: BOPP has higher stiffness and better barrier due to orientation in two directions
Biaxial orientation of BOPP increases crystallinity, stiffness, optical clarity, and barrier properties compared to unoriented cast polypropylene.
Question 6: What does 'ECT' (Edge Crush Test) measure in corrugated board evaluation?
- Resistance to puncture through the board face
- The compressive strength of corrugated board loaded on its edge (Correct answer)
- The bursting strength of the combined board
- The adhesion between liner and medium
Correct answer: The compressive strength of corrugated board loaded on its edge
ECT measures the compressive strength when corrugated board is loaded on its edge, which correlates directly to box stacking strength.
Question 7: In flexible packaging, what is the primary role of a sealant layer in a laminate structure?
- To provide structural rigidity
- To enable heat sealing to form the package and protect the seal interface (Correct answer)
- To act as the primary oxygen barrier
- To provide printable surface for graphics
Correct answer: To enable heat sealing to form the package and protect the seal interface
The sealant layer, typically PE or CPP, is positioned innermost and melts at seal bars to bond the package shut and contact the food product.
CPE Packaging Materials & Components 4
Which test method is commonly used to evaluate the seal strength of flexible packaging heat seals?