06 · Materials, Components & Compliance
Week 6 · 25 hours
Objective
Specify every material in your shoe by name, weight, thickness, finish, supplier and compliance status — and know which choices will cause problems at the bond line, in the die-cut, or at customs.
Why it matters commercially
Materials are typically 45–60% of FOB cost. They are also the primary lever on perceived quality: the same pattern in bad leather versus good leather is a $60 retail difference. And a material chosen without checking bondability, colourfastness or restricted-substance compliance can destroy an entire production run after you’ve paid for it.
Core concepts
Leather
| Type | What it is | Use |
|---|---|---|
| Full-grain | The intact outer grain surface | Premium; shows natural marks; ages well |
| Corrected grain | Grain sanded and re-embossed | Uniform, cheaper, less character; most “leather” sneakers |
| Nubuck | Grain lightly sanded to a nap | Soft matte surface; marks easily |
| Suede (split) | The inner split of the hide, napped | The sneaker workhorse. Cheap-to-mid, great colour range |
| Pig suede | From pigskin | Common in linings and light uppers; distinctive pin-hole pattern |
| Patent / coated | Polymer-coated surface | Bonding and creasing issues; specify carefully |
Specify leather by: type, thickness in mm (e.g. 1.4–1.6mm), tannage, finish, colour reference, tannery, and hide/split origin. Thickness is given as a range because hides vary.
Tannage matters: chrome-tanned is soft, colour-flexible, cheap, and dominant; vegetable-tanned is firmer, patinas, more expensive, and often chosen for sustainability narrative. Ask for LWG (Leather Working Group) audited tanneries — it is the recognised environmental standard and buyers and retailers increasingly ask.
Chrome VI (hexavalent chromium) is a regulated substance formed by improper chrome tanning. It is restricted under EU REACH for articles in skin contact. Require test certification from your tannery or factory. This is not optional; it’s a customs and liability issue.
Textiles
| Material | Spec by | Notes |
|---|---|---|
| Cotton canvas / duck | Weight in oz/yd² (8–14oz typical) | The vulcanized-shoe default |
| Ripstop / nylon | Denier (e.g. 210D, 420D) | Light, technical look |
| Cordura | Denier + branded | Durable, licensed name, costs more |
| Sandwich / spacer mesh | Thickness, open area | Two faces with a monofilament layer between; the athletic standard |
| Engineered mesh | Woven or warp-knit with zoned structure | Modern runner look; needs backers |
| Knit (flat / circular) | Gauge, yarn | Beautiful and modern, but knitting is a specialised factory capability — confirm before designing |
Textiles almost always need a backer (a bonded scrim or foam) to stop stretching and fraying at the die cut. Budget it as a BOM line.
Synthetics
- PU (polyurethane) synthetic leather — the mainstream leather alternative. Quality varies enormously; cheap PU cracks and delaminates within a year. Ask for hydrolysis-resistance data.
- Microfiber synthetics (Clarino, Amaretta and similar) — genuinely high-performance, used in premium athletic footwear, more expensive than mid-grade leather.
- PVC — avoid. Poor environmental profile, restricted phthalate risk, and reads cheap.
- Bio-based / next-gen (mycelium, cactus, apple, recycled-content composites) — real products exist, but check minimums, lead times and durability data. Most have MOQs and prices unsuited to a first run. Note them for V2.
Foams and boards (the invisible layers)
| Component | Common materials | Spec by |
|---|---|---|
| Collar / tongue foam | EVA sheet, PU foam, memory foam | Thickness (3–12mm), density |
| Sockliner | Moulded EVA, PU, latex, OrthoLite | Thickness, density, top cloth, treatment |
| Toe puff & counter | Thermoplastic sheet | Thickness (0.6–1.6mm), activation temperature |
| Strobel board | Non-woven | Weight (g/m²) |
| Lasting board | Cellulose board (Texon, Bontex and similar) | Thickness, flex |
Sockliner is a surprisingly high-leverage component: it is what the customer feels first, and an upgrade from a plain die-cut EVA to a moulded branded footbed is usually $0.80–$2.50 and reads as much more.
Threads, adhesives, hardware
- Thread: bonded nylon, specified by Tex size (Tex 70 / Tex 90 typical for uppers) and colour. Colour-match or deliberate contrast is a design decision — spec it.
- Adhesive: your factory’s choice, but ask whether they use water-based PU or solvent-based systems. Water-based is the modern, lower-VOC standard and increasingly required. Solvent systems are still common in cheaper factories; it’s a worker-safety and compliance signal.
- Eyelets: metal (brass, nickel, gunmetal) or blind. Metal eyelets need a nickel-release test for EU compliance in prolonged skin contact contexts — ask.
- Laces: flat/round/oval, width, length by size, tipping (aglet) material. Lace length changes with size — spec a table, or you will get one length for all sizes.
- Zips / hardware: YKK is the safe default and worth the premium.
Compliance, plainly
You are making a physical consumer product that crosses borders. The floor you must clear:
| Requirement | Where | What it means for you |
|---|---|---|
| REACH / SVHC | EU | Restricted substances in articles. Get a declaration from your factory |
| Chrome VI | EU (and best practice everywhere) | Test certificate for leather |
| CPSIA | US, children’s products | If you ever make kids’ sizes, this becomes a real burden. For adults, largely N/A |
| Prop 65 | California | Warning requirements for listed substances. Common in footwear via certain adhesives/coatings |
| RSL (Restricted Substances List) | Industry practice | Ask your factory for theirs; adopt AFIRM’s published RSL as your baseline |
| Country of origin marking | US import | Permanent, conspicuous, legible marking of country of manufacture — usually printed on the sockliner and/or a label in the quarter lining |
| EU footwear labelling | EU sales | Pictogram labelling of the material of the upper, lining/sock, and outsole |
| Material declarations | Customs | Your upper material composition determines your duty rate. See Module 16 — this is a big deal |
The duty trap, previewed. US import duty on footwear is unusually high and varies dramatically — from single digits to over 30% — depending on the upper material, the sole material, coverage of the foot, and sometimes value per pair. A textile upper and a leather upper on the same shoe can land in completely different tariff lines. Decide your material in Module 6 knowing that Module 16 will price its tariff consequence, and get a customs broker to classify your actual shoe before you commit to bulk. Rates change; never rely on a number you read once.
Sustainability without greenwashing
If you make environmental claims, you must be able to document them, and regulators in the EU and US are actively enforcing against unsubstantiated ones. Safe practice:
- Make specific, verifiable claims (“outsole contains 30% recycled rubber, verified by supplier declaration”) not vague ones (“eco,” “sustainable,” “green”).
- Keep supplier documentation for every claim in a folder before you publish it.
- Certifications worth knowing: LWG (leather), GRS/RCS (recycled content), bluesign (chemistry), OEKO-TEX (textile substances), FSC (packaging).
- The most defensible sustainability claim a small brand can make is honest: made in small runs, to order, from durable materials, repairable, with the factory named.
Do this
1 · Swatch library (6h). Request swatch books and sample cards from at least eight material suppliers — two leather tanneries, two textile mills, two synthetics suppliers, one foam/sockliner supplier, one thread/hardware supplier. Build a physical binder. Label every swatch with supplier, reference, price, MOQ and lead time as the information arrives.
2 · Hand feel calibration (3h). Blind-handle leathers at three price tiers and write down what specifically differs — hand, drape, grain uniformity, edge behaviour when cut, how it creases when folded.
3 · Bondability check (3h). For your top three upper material candidates, email the factory and ask directly: “Do you have any bonding issues with this material class? Do you need a special primer or pre-treatment, and does it add cost?” Log the answers.
4 · Draft BOM v1 (6h). Write your first Bill of Materials — every single component, including thread, laces, eyelets, backers, reinforcements, sockliner, boards, and packaging. You will get this wrong and incomplete. That is the point; Module 13 fixes it.
5 · Compliance file setup (3h). Create a compliance folder. Add: an RSL you’ll adopt, a blank supplier declaration template, and a written list of every certificate you will require before paying a production balance.
6 · Outreach block (4h).
Deliverable. A physical swatch binder with commercial data attached; BOM v1 as a spreadsheet; a compliance folder with your RSL and required-certificate list; bondability answers from your factory in writing.
Self-check
- How do you specify a leather completely? Give every field.
- Why do textiles need backers?
- What is chrome VI and why do you care?
- What determines a footwear duty rate, and why does that make material choice a financial decision?
- Name three defensible sustainability claims and three you should not make.
- What is Tex, and what’s typical for upper thread?
Traps
Specifying a material you can’t get at your volume. Beautiful mill materials often have 300–1,000m minimums. Always ask for MOQ at the same time as price.
Colour matching by screen. Never approve a colour from a photograph or a screen. Use physical lab dips and approve under specified lighting (D65 daylight is standard). Get a signed, dated physical swatch back from the factory and keep it.
Assuming the factory will flag compliance problems. Many won’t unless asked. Compliance is your obligation as the importer of record, not theirs.