Ask for furniture or upholstery, and say if a fogging test is required. Garment fluff is a different offer.
Heat is part of the specification
Upholstery sees car interiors, sunlit sofas, and closed containers. Fatliquors with poor heat resistance or high free volatiles fog glass and leave a smell the tannery did not notice on a cool crust.
Esteem’s furniture-oriented softener note is the place to start, not the highest-offer garment fish-oil blend. The fish-oil blend is excellent for run and fluff and is the wrong assumption for a fogging specification.
Offers written for upholstery
The phospholipid dispersion lists boot nappa, upholstery nappa, and clothing nappa at different shaved-weight levels. The specialty softener lists upholstery nappa and garment nappa separately from softy boot nappa. Those lines exist so the offer is not invented.
Even softness through the cross-section matters on a thick upholstery hide. A surface-only top oil feels pleasant and still cracks or boards when the furniture is upholstered.
What to send the lab
Spew on upholstery is a customer complaint, not a storage curiosity. If you already have spew, send a photograph and the storage temperature.
Finish solvents fog too. Approve the crust oil and the finish stack on separate panels.
| Requirement | Tell Esteem | Weak proxy |
|---|---|---|
| Fogging | The test name and limit | A smell check |
| Heat | Temperature and time | Shop-floor hand |
| Light | Upholstery lightfastness | A four-hour lamp only |
| Handle | Firm or silky nappa | Garment fluff |
Fogging is volatility
The fogging test heats the leather and collects what evaporates. Low-molecular-weight emulsifiers, residual solvents, some fungicides, and lighter fractions of natural or process oils are the usual contributors. A fatliquor can be non-fogging as a neat oil and still fog if it arrives with a volatile emulsifier, or if the tannery adds a solvent dye or a finish thinner that the test also sees.
Heavier triglycerides and well-chosen synthetic oils contribute less volatility and more risk of spew if they are not bound. The upholstery brief has to name the test method and the limit. A pass on a 100 °C screen is not a pass on the automotive method the seat maker uses.
Spew is migration
Solid fats and waxes move when the leather is warm and then crystallise on the surface as it cools. Natural fat that was never dispersed, and process oils with a melting range near room temperature, are typical. The bloom can be wiped off and then return, which is the storage complaint on furniture hides.
A dispersing fatliquor reduces spew by distributing natural fat. Adding more soft oil reduces the chance of a dry centre and increases the mobile fraction if that oil itself can travel. Heat-and-light grades used for furniture nappa are chosen because they are meant to stay and to resist discoloration, not because any soft oil is an upholstery oil.
What the trial has to include
Run fogging on the finished leather, not only on the crust, because finish solvents and lacquers fog. Run a heat-and-cool cycle for spew on the crust and on the finished hide. A leather that is clean on the day of fatliquoring can bloom after a week in a warm warehouse.
Write the current fatliquor, the fungicide, and the finish system on the request. Changing only the oil when the fungicide is the volatile fraction produces a new sample that fails the same test.
How to Specify with Esteem
- State furniture, auto, or contract upholstery.
- Name any fogging, VOC, or odor test.
- Prefer grades whose notes mention heat and furniture nappa.
- Do not use the highest garment fish-oil offer as the default.
- Age a panel in heat before you approve hand.
The synthetic specialty softener on fatliquors is described for furniture, garments, and shoe nappa with heat resistance. Phospholipid grades list upholstery nappa offers.