Unit 4 Part B - Corks

Question 1

What are the types of crown (RTD)

Answer 1

Stainless steel
electrolytic tin plate
Tin Free Steel

Question 2

Which out of the three main crowns (RTD’s) is most common?

Answer 2

Tin Free Steel

Question 3

What are the benefits of the use of Tin Plate?

Answer 3

TP gives for corrosion protection and may be favoured when packs are shrink wrapped.

It has a shiner appearance so is more susceptible to scratching.

Question 4

What is stainless steel best used for?

Answer 4

Corrosion protection but is very expensive.

Question 5

How can corrosion be avoided on crowns? (RTG)

Answer 5

Bottles must be effectively dried under the crown skirt. This should be carried out with air jets before the labeller, at the correct angle, carrying high volume air, at a low pressure.

Stand alone air compressor is most satisfactory solution.

Question 6

What is known as a “Aluspot Crown”?

Answer 6

An aluminium spot was used to cover the cork & act as a liner and a seal.

Question 7

Describe a PVC plastisol.
.

Answer 7

These crowns have foamed liners which is forgiving when applied to returnable bottles which could have a slightly damaged sealing area.

Question 8

What is more commonly used crowns today? (RTG)

Answer 8

PVC & PVC dry blends.

Which are suitable for good pressure retention before and after pasteurisation, stacking, oxygen barrier, and scavenging with soft & hard polymers, a double lip design is used.

Question 9

What does corks consist of?

Answer 9

The thick outer bark of the cork oak (quercus suber)

Question 10

Why is cork harvested during spring/summer?

Answer 10

Breaks away easier with no damage.

Question 11

Describe the manufacturing of corks (wine stoppers)

Answer 11

seasoned cork plants are stacked flat and boiled for at least one hour.

boiling allows individual cork cells to fully expand into a tight “honeycomb” cell structure.

This makes the cork plant flatter smoother more pliable & causes plank volume to expand about 20%.

After a 3 week resting period, the trimmed planks are sliced into strips along the length of the plank.

Corks are punched from the cork strips with a sharp cylindrical knife, which determines the width.

There is no wasteage.

Corks stoppers are graded and sorted by a number of criteria.

Corks which are selected are washed and disinfected in a variety of methods.

Corks are then printed to meet customer specifications using ink, roller or traditional branding.

Question 12

What is the most common way to disinfect corks (wine)

Answer 12

a watery solution of hydrogen peroxide.

Question 13

What is the difference of manufacturing wine corks in comparison to spirits?

Answer 13

Once the cork shanks are punched they are then finished & shaped on a lath to add the bevelled or chamfered edge.

Cork shanks are then tumble waxed using a good grade wax.

Shank is then bonded to the stopper using a food grade hot self adhesive.

Question 14

What are the different materials that stopper heads can be made out of?

Answer 14

Plastic, wood and metals such as Zamac.

Question 15

What are the advantages of corks?

Answer 15

100% natural, biodegradable & recyclable.

Lowest carbon closure solution.

Easy to handle & manufacture

easy insertion & removal of cork - allows for a degree of rough handling without breakage.

Question 16

Where do debris come from?

Answer 16

comes from seed holes in the surface of the cork which can open up further once the cork is under compression in neck of the bottle.

Question 17

Describe the issue of Taint.

Answer 17

taint is much more serious.

Taint is caused by the presence of 2,4,6 triloroamisole.

This compound gives a musty odour which is detectable at a very low concentration.

Question 18

What are the two most common metal closures?

Answer 18

STEL and ROPP

& aluminium is the most common material used in manufacture.

Question 19

Describe metal closure manufacture.

Answer 19

The flat aluminium alloy sheet is first coated & decorated using an off-set litho printing process, using inks and varnishes which are normally baked or ultra violet cured.

The design will determine whether the entire decoration is applied at this point or the top print only. As the metal will be stretched and can distort any imagery.

Once ink & varnish is dried, circular blanks, are cut from pre - printed aluminium alloy sheets & drawn into a shallow wide cup with flange, which is then redrawn into the required diameter & trimmed in a separate operation.

The decorated shells then pass through the tooling process where the features such as knurling, bridges, embossing or side shaving are applied.

Final stage - lines/fitments (wads) are added.

Question 20

What is knurling?

Answer 20

Is usually added to a closure for aesthetic reasons, or to provide better grip for the consumer when opening the closure.

Question 21

Why is the wad/liner added?

Answer 21

to provide a seal between the glass and aluminium shell of a closure.

Question 22

What are wads made from?

Answer 22

cardboard lined with PET, or from expanded polyethylene which can also be faced with PET.

Question 23

Explain the manufacturing of Plastic closures.

Answer 23

Plastic material (pellets) are loaded onto a hopper on top of injection unit.

Pellets are fed into the injection cylinder where they are heated until they reach molten form.

Molten pellets is mixed and is forced to the end of the cylinder.

Once there is enough material at the front of the screw, the injection process begins.

Question 24

What is torque?

Answer 24

Is the resistance to application or removal of the closure.

Question 25

What are the two main functions of packaging?

Answer 25

Technical functions
Marketing functions