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Sustainability Questions for Bag Makers

Why the questions matter more than the answers

Almost every bag programme can produce a reassuring sentence. Far fewer can produce a file. The gap between the two is where greenwashing lives, and it is usually not deliberate: a sales team repeats what a material data sheet says, the data sheet repeats what a polymer brochure says, and nobody upstream ever measured anything. The only defence is to ask for the artefact rather than the assertion.

The second reason to ask questions rather than accept claims is that sustainability on a welded waterproof bag is genuinely complicated. The shell is a laminate of two or three polymers, the seams are fused rather than sewn, the hardware is metal or acetal, and the closure is a geometry rather than a material. Each of those has its own compliance story, and a claim that is true of one layer may be false of the bag.

Material traceability: prove where the polymer came from

Start at the polymer. For a recycled claim you want a transaction certificate that names the input lot, the recycled percentage by weight, and the date range it covers, issued under a recognised chain-of-custody scheme. Without the certificate, the percentage is arithmetic done on a spreadsheet, and spreadsheets do not survive an audit or a retailer review.

Ask the same question about the face fabric, the film, the webbing and the hardware, because they are usually four different supply chains. A bag described as recycled is often a recycled face fabric laminated to a virgin film, which can be legitimate and clearly stated, or quietly misleading. Request the split by component and by weight; a 20L bag at 480 g might be 62% recycled by mass with the film making up the other 38%.

Recycled content: the certificate and the arithmetic

Recycled percentages are weight-based and easy to overstate. A bag with a recycled polyester face and a virgin TPU film may be reported as a recycled bag when the face is only 40% of the mass. Work out the weighted figure yourself: face fabric share times face recycled share, plus film share times film recycled share, plus hardware and trim at zero. If the number you calculate and the number on the spec sheet disagree, ask why before you print anything.

Then check the certificate dates against your production window. Transaction certificates are issued per shipment and expire with the lot they cover; a certificate from last spring does not cover a production run this autumn. Ask for the certificate to be issued against your order, with your order number on it, and keep it in the same folder as the inspection report and the bill of lading.

Chemical management: restricted substances and declarations

Restricted substance compliance is the part of the conversation that carries legal risk rather than reputational risk. In the European Union, REACH restricts a long and regularly updated list of substances of very high concern, and the four listed phthalates are capped at 0.1% by weight of the article. A declaration is the starting point, but a test report from an accredited laboratory is what you need for anything sold into retail.

Scope the testing to the whole article rather than to the fabric. On a welded bag the ink, the seam area, the webbing dye and the buckle can each carry a different risk, and a fabric-only report leaves three of those four unexamined. Ask for article-level testing on the finished product in the colourway you are actually buying, because a pigment that passes in black may not pass in a bright orange.

PFAS and water repellency: what to ask

Fluorinated chemistry has been used for decades to make fabrics shed water and oil, and it persists in the environment for a very long time. On a TPU or PVC laminate the film itself does the waterproofing, so a durable water repellent finish on the face fabric is optional and often absent. That is a genuine advantage of laminated construction over a coated woven fabric, and it is worth saying out loud in a specification.

The question to ask is narrow and checkable: is any PFAS intentionally added at any stage, including the face finish, the ink and the thread. The evidence is a total fluorine screening result, usually reported with a detection limit, plus a signed statement covering the whole bill of materials. Guidance on persistent chemicals and their measurement is published by the EPA, and our own notes are in PFAS-free waterproof fabric.

PVC, phthalates and plasticiser-free claims

PVC is the cheapest way to make a soft, weldable, waterproof film and the hardest to defend on sustainability grounds. It carries chlorine, it needs plasticisers to stay flexible, and it contaminates most other polymer recycling streams. A bag programme that wants a credible end-of-life story almost always ends up specifying TPU, which carries no plasticiser and no chlorine.

If PVC stays in the specification for cost reasons, be precise about which claim you can make. Plasticiser-free is a different claim from phthalate-free: the first means no softening additive at all, the second means the restricted phthalates are below the legal limit. Both are testable, and conflating them is the most common source of a corrected product page after a retailer review.

Energy, carbon and what a footprint number includes

Carbon numbers are meaningless without a boundary. A figure quoted cradle-to-gate covers raw material, polymer production, fabric making and bag assembly, and stops at the dispatch door; it excludes shipping, retail and use. Ask which boundary was used, what the functional unit was, and whether the number was reviewed by anyone outside the organisation that produced it.

Then look at where the mass actually is. On a welded TPU roll-top, the polymer dominates, so the biggest lever by far is material choice and material yield, not site electricity. Better nesting on the cutting table routinely removes 4 to 7 percentage points of waste, which is worth more than most lighting and motor upgrades combined. The measurement conventions are set out in the ISO greenhouse gas standards.

Water, effluent and finishing processes

Water use on a welded bag is small compared with a sewn textile product, because there is no dyeing and no washing in the assembly stage. The water story sits upstream in fabric dyeing and in printing. Screen printing uses more water in screen washing and generates ink waste; digital printing uses less water and more electricity, and produces almost no screen wash effluent.

Ask two questions here: what is the water consumption per printed panel, and how is the ink waste and wash water handled. A credible answer names an effluent permit, a treatment route and a testing frequency. A vague answer about responsible water use is worth exactly as much as it sounds. Printing choice is covered in more depth in water-based printing ink.

Waste, offcuts and the cutting room floor

Offcuts are the largest physical waste stream in bag assembly, and the rate is a design variable. A simple cylindrical roll-top body nests well and yields 8 to 11% waste; a shaped backpack panel set with radiused corners and a harness yields 14 to 18% before any nesting work. That difference is several tonnes of laminate a year on a mid-sized programme and it is entirely decided before production starts.

Ask what happens to the offcuts. On a single-polymer TPU line they can be reground and re-extruded into non-critical parts such as stiffeners or packaging inserts; on a mixed line they are usually sent for energy recovery. Then ask whether the programme will accept a regrind content limit in the spec, because that is the point where a sustainability goal turns into an actual engineering constraint.

Packaging, extended producer responsibility and freight

Packaging is governed by rules that change by market and by year. Extended producer responsibility schemes in Europe charge fees by material and mass and require registration in each country where the packaging ends up, so a single pan-European programme means several registrations and several reports. Ask who registers, who pays, and where the identifier appears on the packing documentation.

Freight is the other half of the packaging decision, and it usually dominates the environmental arithmetic. A pack that is 30% larger in volume ships fewer units per container, and one container of air is often worse than the difference between a polybag and a paper wrap. Right-sizing beats material substitution in almost every calculation, which is why the first question should be about dimensions rather than about film type.

Social compliance and the audit trail

Social compliance is the area where buyers most often accept a logo instead of a report. An audit is a snapshot with a validity window, typically twelve months for a four-pillar assessment, and it names a site and a date. Ask for the report itself, not the certificate: the report names the findings, the corrective actions and the closure dates, which is the part that tells you whether anything improved.

Check three things on every audit: the site address matches the site that will make your goods, the scope covers the processes you are buying, and the date is inside the validity window. A report covering cut-and-sew does not cover welding; a report for one building does not cover a second. Ask for the worker numbers and the line count so the scope has something concrete attached to it.

End of life: repair, second life and recyclability

A bag that lasts twice as long halves its footprint per year of use, which makes durability the most effective sustainability lever available and the least glamorous. Ask what the expected service life is, what the failure modes are, and whether spare buckles and straps are available as parts. A programme that can ship a replacement buckle is a programme that keeps bags in service.

Then ask about the polymer story at end of life. A single-polymer TPU shell with a TPU window and no adhesive-bonded trim is mechanically recyclable in principle and far easier to deal with than a mixed laminate. Mixed materials are not automatically bad, but they need an honest answer: if the bag cannot be recycled, say so, and put the effort into repair and service life instead. More on this trade-off is in how recyclable dry bags are.

A question set you can send today

• Send the full bill of materials with polymer, weight and origin for every component.
• Provide the transaction certificate for any recycled claim, issued against this order.
• Provide an accredited laboratory report for restricted substances on the finished article in this colourway.
• Confirm in writing that no PFAS is intentionally added, and give the total fluorine result.
• State the carbon boundary, functional unit and whether the figure was externally reviewed.
• Give the cutting yield for this pattern and the destination of the offcuts.
• Name the audit scheme, the site address, the scope and the report date.
• Confirm who registers packaging in each destination market and quote the identifier.

Send the set as a numbered list and expect numbered answers, because that format makes evasion visible. A partner who can answer eight of eight with documents is a partner worth a long relationship; one who answers five and offers assurances for the rest is telling you something accurate about how the programme will run when something goes wrong. Score the replies and keep them with the order file.

Our own answers to that set are documented and dated: production since 2014, an SGS-verified 4,950 m2 facility with 137 staff across seven lines, 149 machines and a 200,000-piece monthly capacity, material traceability held to transaction-certificate standard, and inspection to AQL 2.5 before shipment. Minimum order is 500 pieces, sampling takes 6 to 10 working days and bulk runs 35 to 50 days from Xiamen.

If you want the shorter version to work from, the buyer-facing checklist in sustainable dry bag buying checklist compresses all of this into a single page, and the legal detail sits in REACH compliance for dry bags. For the two claims that most often need correcting on a product page, read biodegradability claims explained and plastic-free packaging before you commit any wording to print.