1. Which of the following materials is the outermost lamination layer in tetrapacks?
a) Polyester
b) Polypropylene
c) Polyethylene
d) Polystyrene
Discussion
Explanation: Polyester is the outermost lamination layer in tetrapacks. Polyester provides strength to the tetrapack. It also acts as an excellent printable surface. Polypropylene is the innermost layer, the food contact layer. Polyethylene and polystyrene is not used in tetrapacks.
2. Polymers used for packaging films must have a surface energy – _______
a) 5-25 mNm-1
b) 29-45 mNm-1
c) 45-55 mNm-1
d) 10-25 mNm-1
Discussion
Explanation: Polymers used for packaging films must have a surface energy- 29-45 mNm-1. The standard is set by ASTM. Also, the surface energy of the substrate should be 7-10 mNm-1 higher than the surface tension of coating being applied.
3. Smart blending works on the principle of ________
a) Chaotic addition
b) Chaotic advection
c) Chaotic adversion
d) Chaotic abstraction
Discussion
Explanation: Smart blending works on the principle of chaotic advection. It refers to the chaotic (non-periodic) motion of a particle in a fluid that can occur even where the flow field is simple and periodic, which causes successive shear deformations and reorientations.
4. A __________ is a highly concentrated blend of an additive and a carrier resin.
a) Masterpolymer
b) Mastermixture
c) Masterbatch
d) Masterblend
Discussion
Explanation: A masterbatch is a highly concentrated blend of an additive and a carrier resin. A masterbatch is a highly concentrated blend of an additive with a a carrier resin that should be compatible and miscible in the resin into which it is being blended. Film manufacturers commonly blend a masterbatch into the resin at the extruder feed hopper when making film or sheet.
5. Which of the following metal is not used in vacuum metallization?
a) Aluminium
b) Nickel
c) Chromium
d) Sodium
Discussion
Explanation: Sodium is not used in metallization. Vacuum metallization is a method in physical vapour deposition process and produces coatings by thermal evaporation of metals in a vacuum. Physical method includes vaporization of the metal, which is later deposited on the surface by condensation.
6. Which of the following is not a heating source in metallization?
a) Convection heating
b) Resistance heating
c) Induction heating
d) Electron beam heating
Discussion
Explanation: Convection heating is not a heating source in metallization. In resistance heating, aluminium wire is fed onto a block of metal that is heated by holding it in a carbon crucible or boat across which a high current is arched. A pool of melted metal forms in the boat cavity and evaporates into a cloud above the source. In induction heating, heating is done by passing a high current through heating coils, causing an induced magnetic field inside the coils. In electron beam heating, the source is heated by electron beam.
7. Energy of an electron is upto ______ in electron beam heating.
a) 15eV
b) 15keV
c) 30eV
d) 30keV
Discussion
Explanation: Energy of an electron is upto 15keV in electron beam heating. Electron beam heating allows tight control of the evaporation rate and although more expensive, it is notably simpler and much more versatile as it can be used to evaporate many different materials. It must be ensured that no secondary electrons impinge on the polymeric web.
8. Adding more metal during the metallization process increases barrier properties.
a) True
b) False
Discussion
Explanation: The given statement is true. Metallization process has a strong and complex effect on the development of adhesive and barrier properties of metallized films. Thicker films leads to adhesion problems and even flaking, if the metallized layer becomes too thick. The thinner coatings tend to be full of pinholes and may even be transmitted lights to some degree.
9. __________ is a PVD technique in which the bulk material is released into the vacuum by bombardment from an ion source.
a) Splattering
b) Sputtering
c) Splashing
d) Spreading
Discussion
Explanation: Sputtering is a PVD technique in which the bulk material is released into the vacuum by bombardment from an ion source. The material coalesces onto the substrate surface, thus forming a thin film.
10. _____________ involves depositing successive layers of different substances to produce layered, crystalline films.
a) Atomic layer chemical vapor deposition
b) Combustion chemical vapor deposition
c) Low pressure chemical vapor deposition
d) Plasma enhanced chemical vapor deposition
Discussion
Explanation: Atomic layer chemical vapor deposition (ALCVD) involves depositing successive layers of different substances to produce layered, crystalline films. In short, ALCVD is a method in chemical vapor deposition in which deposition occurs through chemisorption of pulsed chemical reactant.