View Count：30
Date：2026-09-22How do you stop felt mould on export bags and pet beds? Wool needle-felt is a porous protein fibre, so one damp season leaves it mouldy and beetle-ridden, and the batch is downgraded or reworked. Run the finish line with iHeir-BJ textile anti-mould agent at 2-3% o.w.f., then pack with iHeir-D paper at 0.1-0.2 g of active per sheet. This article covers the bath recipe, the drying moisture bar and the packing step with the dosing to copy.
1. Why felt both moulds and attracts insects
Felt is a nonwoven needled from wool or synthetic fibre; without warp and weft to bind it, it holds far more air gaps than woven cloth. Wool is a keratin protein with a moisture regain around 15%, so it takes up water as soon as the air turns humid. Inside a felt layer there is little air movement, the moisture cannot leave, and spores landing on protein-rich fibre show grey-white spots within two or three days. Insects are the second front: carpet beetle and clothes moth larvae feed on keratin and breed fastest at 20-30°C and above 60% humidity, so beetle holes usually appear alongside the mould.
Felt shipments from a plant like Nangong are mostly bags, pet beds and storage baskets. They share two traits: they are bulky with thick interiors that trap damp heat, and they ship in pale natural shades where mould and beetle damage stand out at first inspection. Mould and insect control have to run together. Every time the felt passes through cutting and sewing hands it picks up skin oils as well, which is food for both spores and eggs; for the workshop-and-warehouse side on nonwoven rolls, our nonwoven mould piece goes deeper.
2. The finish line: mixing the pad-batch bath
The process we recommend is pad-dry with iHeir-BJ textile anti-mould agent. It is a non-leaching bound antimicrobial: the molecules bond chemically to the fibre surface, so they do not bleed or migrate, and the protection lasts as long as the article itself, which suits felt still to be sewn and pressed after treatment.
Copy the bath card: dose 2-3% o.w.f. on dry fabric weight, so 2-3 kg of stock for 100 kg of felt; bath temperature 21-50°C, ideally under 48°C; pH 4.5-8.5, ideally about 6, in soft water. Pre-mix the iHeir-BJ with 9-13 times its weight of water before it enters the bath, so the neat stock never hits the fabric at full strength, and squeeze to a 70% pick-up before the dryer.
Two rules are absolute. First, iHeir-BJ is cationic and must never share a bath with an anionic auxiliary, or the liquor flocculates and the whole tank is lost; if you need an anionic softener or a repellent finish, run two passes, iHeir-BJ first, dry, then the anionic. Second, iHeir-BJ contains silicone, which can pull moisture regain down; for felt used next to skin as a wicking layer, add 0.1% cationic hydrophilic agent to bring absorption back. Storage baskets and pet beds are not sensitive to that, so they can skip it.
Dose and life run together: at 2% o.w.f. protection holds over one year, at 3% it stretches to two or three. Run 3% for humid destinations or long shelf-life orders. Verification needs no laboratory: a drop of bromophenol blue (BPB) on a finished piece shows in two minutes whether the layer is present.
3. Drying and warehousing: moisture is the hidden spec
After the pad-dry bath comes drying, and the acceptance number is moisture content, not minutes. Felt is thick and releases water slowly; crate it under-dried and the damp core turns the carton into an incubator. We check moisture regain after drying and move goods to the finished store only when they balance with workshop air; in a rainy season the workshop is humid, so drying times stretch.
The warehouse needs rules as well. Keep felt off the floor on pallets, leave a fan gap between stack and wall, and never store along the damp floor line. A dehumidifier beats propping the doors open in the wet months; sample two pieces from the top, middle and bottom of each stack, rest a hand on the weave for ten seconds, and a cold damp feel means the unit goes on. Clumsy as it looks, this routine saves a full-batch rework.
4. The packing step: gas-phase paper and tablets together
Once felt is packed, the carton is a closed microclimate, and day-night temperature swings in transit condense moisture on the inner walls. Add iHeir-D gas-phase anti-mould paper at the packing step: a printed ink layer carrying particles under 5 microns releases its active slowly into the air and catches spores no sheet touches, at 0.1-0.2 g of active per sheet. Poor dyes can bleed and cheap metal fittings can corrode under damp, so a dyed felt order runs a compatibility trial first: three times the normal quantity in a closed box, with the paper separated from the sample, checked after several days for colour change and corrosion.
Where insects are the bigger worry, on pet beds and high-wool bags, add Power Pak anti-mould and deodorizing tablets. The active is allyl isothiocyanate drawn from wasabi and mustard, released by sublimation to kill penicillium and aspergillus, and the black grade adds a natural insect repellent for the beetle side. Drop the tablet in as the product enters the box and seal at once: sterilisation completes within 72 hours. The green grade holds six months, blue and black twelve, so match the grade to the transit cycle. The vapour is pungent, so ventilate the packing area and wear rubber gloves; any box opened more than 15 days after sealing must take a fresh tablet, because the gas has dispersed. Pet-product mould logic on this line echoes our pet supplies anti-mould piece.
5. Dosing at a glance
Three steps, three products, one sheet to run the line by:
| Product | Step on the line | Recommended dose | Key points |
|---|---|---|---|
| iHeir-BJ textile anti-mould agent | Finish, pad-dry | 2-3% o.w.f., 70% pick-up | Bath 21-50°C, pH 4.5-8.5; cationic, never with anionic auxiliaries |
| iHeir-D gas-phase paper | Packing | 0.1-0.2 g of active per sheet | Dyed goods run a 3x dosage compatibility trial first |
| Power Pak tablets | Packing (insect control) | In the box as goods are packed, sealed at once | Kills within 72 h; green 6 months, blue/black 12; re-tablet after a 15-day opening |
The order never changes: finish first to bind the agent into the fibre, then paper to protect the air in the box, then tablets to close the insect gap. For a new style, a new felt supplier or an off-season reorder, re-mix a lab sample against these ranges before running the line.
6. FAQ
Q: The felt is already mouldy. Can it be saved?
It depends how deep the mould sits. Surface bloom wipes off with an iHeir-Clean type spot cleaner and dries back to saleable; where mould has penetrated the layer with a musty smell and brittle fibre, rework costs more than downgrading, so move the batch to liners or hidden parts.
Q: How do I choose between 2% and 3%?
By shelf life and transit cycle. Domestic orders that clear within six months run at 2%; exports to Europe or the US with a year or more of sea freight and channel time run at 3%, which stretches protection to two or three years.
Q: Will the finish change the hand or colour of the felt?
iHeir-BJ bonds at the fibre surface and leaves the hand and shade unchanged, with no yellowing on pale goods. The silicone-related drop in moisture regain only matters for next-to-skin pieces, which take 0.1% cationic hydrophilic agent to correct.
Q: Can one process cover orders to different countries?
The process holds; the files and doses differ. iHeir-BJ is registered with the US EPA and carries an oral LD50 of 12.65 g/kg; send us the destination and transit cycle and we configure the order. Contact us for a sample and drum pricing.
