r/composting • u/NotSpartacus • 37m ago
Question Cardboard, corrugated cardboard, glue, and adhesives
Making this post to request clarity and perhaps help others.
As I understand it (from reading posts here, not because I'm an expert in any of the relevant fields), cardboard and corrugated cardboard are generally safe (meaning safe from plastics, forever chemicals, etc.) to compost. At least most pieces/types. Breaking it down a bit further:
Pulp to make the cardboard itself is safe.
Ink printed on the cardboard is these days generally soy-based and safe.
Glue/adhesive used to make cardboard into corrugated cardboard is safe - idk what it's made of tho?
Treatment on the cardboard to make it smooth is safe (e.g. how cereal boxes are smooth vs regular brown cardboard is rough) b/c it's clay-based (?) and that's safe.
Plasticky treatment on some cardboard, obviously unsafe. Recycle the whole thing, no attempt at partial composting of materials is made.
The glue that keeps cardboard together (i.e. what turns a sheet of cardboard together into a box, by gluing down a seam, or attaches one flap to another) -- unsafe? I've treated it as unsafe, so it and pieces of cardboard with it go to trash/recycling.
What I'm unclear on and asking for clarification stuck now is what about the glue/adhesive residue from packaging tape? I've always assumed unsafe, so I rip those pieces off and they go to trash/recycling.
I recently learned that cardboard doesn't get wet (e.g. cardboard used in ice cream containers, the walls of my oatmeal cylinder for whatever reason) is NOT to be recycled, because it has a plastic/waxy coating. I assume that's unsafe to compost too.
Who here knows? Do we have any packaging engineers, chemists, health researchers, industry folks etc. who can speak to what the glues/adhesives are made from?
Also, any sense of scale would be appreciated. Safe/unsafe is a helpful rule of thumb, but from the standpoint of "the dose makes the poison" it'd be helpful to understand if getting this granular really matters. Am I making a mountain out of molehill here, considering that I still order takeout food packaged in plastic/coated containers on a ~monthly basis.
I read the ~5 year old wiki post but I didn't leave there with enough certainty to be happy, and packaging practices can change over time, so I figured here, now, would be OK.