The Role of Bonded Warehousing and Logistics in the Supply Chain

In plastic raw material trading, price gets discussed and logistics does not. Yet a converter's real cost is not set by the price per tonne. It is set by when the material reaches the line and in what condition. A container stuck at the port, a big bag that has picked up moisture, a lot that can no longer be traced: each erases the few dollars per tonne you negotiated. This article covers what a bonded warehouse does, how it changes the customs and tax position, and what disciplined polymer storage looks like.

What a bonded warehouse does

A bonded warehouse is a customs-supervised facility where goods are stored before import duties are paid. The cargo is physically in the country but has not yet entered free circulation. Customs duty, VAT and any additional levies fall due only when the goods are withdrawn, and only on the quantity withdrawn.

The cash flow consequence of that single rule is significant. Instead of paying the full duty on a 500-tonne shipment at once, a converter can draw 80 to 100 tonnes a month and align the fiscal burden with production and collections. Working capital is not locked into inventory. Goods held under bond can also be re-exported: material redirected to a third country never triggers import duty at all. Where demand visibility is poor, that option value alone justifies the arrangement.

Warehouse types in brief

Turkish customs legislation splits bonded warehouses into general and private categories, with sub-types defined by who bears responsibility:

• Type A: General warehouse. The operator serves all parties and is liable for the goods. This is the standard commercial model.
• Type B: General warehouse. Liability rests largely with the owner of the goods; the operator provides the space.
• Type C: Private warehouse, used only for the operator's own goods. It suits manufacturers with steady, predictable volume.

For a distributing raw material supplier, a Type A general warehouse is usually the right structure. It allows many customers to draw from different lots at different times. Tacirler Antrepo performs exactly that function at Hastane Mah. 29 Mayıs Cad. No:40, Hadımköy (+90 212 771 07 90). The Topkapı warehouse at Maltepe Cad. No:10 provides a second layer for fast intra-city dispatch of goods already in free circulation.

Port to warehouse to plant, and where demurrage starts

A bill of lading is issued at the load port, the vessel arrives at Ambarlı, Gemlik or Mersin, containers are discharged, a warehouse declaration is lodged and the cargo enters the bonded area. From that point the clock is running.

Two cost lines get conflated but are not the same. Demurrage accrues daily when a container stays beyond the free time granted by the carrier. Storage is the charge for occupying warehouse space. Free time is typically seven to fourteen days, and a missing document or a pending laboratory analysis will consume it quickly. On a twenty-container parcel, a few days of delay moves the landed cost per tonne by a visible margin.

What prevents it is unglamorous: the bill of lading, certificate of origin, certificate of analysis and invoice complete before the vessel berths. Assembling paperwork after arrival is a decision to pay demurrage.

Consignment stock and just-in-time supply

Bonded stock creates a buffer between supplier and manufacturer. Under a consignment model the material is physically in Türkiye, but ownership and the tax burden transfer only at the moment of withdrawal. That produces three concrete effects on production planning:

• Lead time drops from a 45 to 60 day ocean transit to a few days, which widens the order acceptance horizon.
• Safety stock sits with the supplier, so the manufacturer's inventory turnover is not distorted.
• There is no need to commit to large volumes in a single decision during price volatility.

The model demands discipline in return. Consignment stock that is not fed by realistic drawdown forecasts becomes dead inventory. Sharing a monthly withdrawal plan with the supplier is a precondition, not a courtesy.

Handling: big bags, octabins and 25 kg sacks

Packaging format dictates warehouse operation. A 25 kg sack is stretch-wrapped on a pallet and stacked manually or by palletiser; it splits easily into small parcels but is labour-intensive. Big bags of 1,000 to 1,250 kg need forklifts and lifting frames and suit line-side feeding stations. Octabins are preferred for engineering plastics and low bulk density grades, but stacking height is limited and they are more moisture-sensitive than sacks.

The critical point for stock integrity is verifying packaging condition at every handling step. A torn big bag is not only lost material, it is a contamination risk. Where several polymer families share a floor, cross-contamination shows up later on the converter's line as gels and black specks.

Moisture, UV and temperature in polymer storage

Polyolefins tolerate moisture. PET, PA6 and PC do not. These hygroscopic resins absorb ambient moisture once packaging is opened, and processing without drying causes hydrolytic degradation: haze in PET preforms, loss of mechanical strength in PA6.

• Avoid prolonged outdoor storage. UV embrittles the packaging itself before it affects the resin.
• Keep warehouse temperature stable. Day-night swings drive condensation inside the packaging.
• For hygroscopic grades, open packaging only on the day of use and reseal any remainder.
• Always store on pallets. Never stack directly on concrete.

FIFO is not negotiable. Antioxidant and UV additive packages lose effectiveness over time. A lot that has sat for eighteen months will not behave like a fresh one even though it meets the same specification. The layout has to make FIFO physically possible; aisle design should be built around it rather than retrofitted.

Lot traceability

Every shipment should map one to one between the producer's lot number and the warehouse stock record. When a quality issue surfaces at a customer, the first question is always the same: which lot, which date, which vessel, which container. If that chain is broken, the recall covers the entire stock. With traceability in place, exposure narrows to a few pallets. The difference in a single incident can exceed a full year of logistics budget.

Lead time and production planning

What matters to a planner is not average lead time but its variance. A chain averaging 20 days with a 12-day deviation demands far more safety stock than one averaging 30 days with a 2-day deviation. That is the real contribution of local bonded stock: less about shortening lead time than about making it predictable. Teriş has imported, distributed and financed plastic raw materials since 1961, and the storage infrastructure at Hadımköy and Topkapı exists to build exactly that predictability.