dcf.cymru stimulus sheet · Design Technology · Year 10

Packaging material datasheet

Six materials, with their real drawbacks. None of them is the right answer to everything.

The six materials

Material	Weight or thickness	Cost per m²	Kerbside recycling in Wales	Honest drawbacks
A. Recycled cartonboard	350 gsm	£0.42	Yes — card is collected almost everywhere	Grey-brown base, so printed colours look dull. No grease resistance: butter marks show through within a day. Recycled fibre is shorter, so it needs to be thicker than virgin board for the same stiffness.
B. Virgin FSC cartonboard	300 gsm	£0.58	Yes	Uses new fibre, even if from a certified forest. Best print quality of the six. Still no grease resistance.
C. Corrugated board, E-flute	2 mm, about 500 gsm	£0.65	Yes	Much the strongest, so it protects fragile contents, but it is bulky: you fit far fewer empty boxes on a delivery pallet, which pushes transport emissions up. Print is coarse.
D. rPET window film	0.25 mm	£1.90	In theory yes, in practice usually no	Made from recycled bottles, and it shows the product, which sells it. But a card box with a plastic window is a mixed-material pack: sorting lines commonly reject it, so the whole box ends up as residual waste rather than just the film.
E. PLA bioplastic film	0.20 mm	£2.30	No	Made from plant starch and marketed as compostable, but it only breaks down in industrial composting at high temperature. It is not accepted in Welsh kerbside food-waste or recycling collections, and if it goes in with the plastics it contaminates them. "Compostable" is not the same as "compostable here".
F. Greaseproof glassine paper	40 gsm	£0.30	Yes, and home compostable	Solves the grease problem cheaply as an inner liner, and paper inside a paper pack keeps the whole thing single-material. It is not fully greaseproof for more than about three days, and it has no structural strength at all.

Finishes — the part people forget

Water-based inks: no effect on recyclability. Colours slightly less punchy.
Plastic laminate or gloss film: looks premium and wipes clean, but it makes card unrecyclable in most kerbside collections. One decorative choice can cancel out the whole material choice.
Spot varnish: water-based versions are fine; solvent-based are a problem.
Glue: a small amount of ordinary PVA-type adhesive is tolerated in card recycling. Double-sided tape and self-adhesive plastic labels are not.

Numbers you will need

gsm means grams per square metre. Mass of a blank = area in m² × gsm.
1 m² = 1,000,000 mm². 1 cm² = 100 mm².
Each Welsh cake is about 60 mm across and 15 mm thick. The pack must hold six.
The school will sell 120 boxes at the enterprise fair.
Board is bought in A3 sheets, 420 mm × 297 mm. Your net must fit on one sheet.

How to draw a net that actually closes

For a box of length L, width W and height H, the four side faces form a strip. The strip must be exactly the perimeter long: 2 × (L + W).
The top and bottom panels each have to be L × W, or the opening will not be covered.
Add a glue tab of 12 to 15 mm on the last face, and tuck flaps of about 25 mm on the lid.
Check before you draw anything else: does the strip length equal the perimeter? If not, the box will not close.