Polylactic Acid (PLA) and Low Density Polyethylene (LDPE) are the two most quoted options for plastic films and flexible packaging in marine and offshore projects. Both are widely available, but they behave very differently once they are in service.
This guide is written for engineers, purchasers and project managers who need a practical answer, not a resin data sheet.
This category covers a family of products rather than a single item. In practice a buyer defines plastic films and flexible packaging by three things: the base resin, the format or dimension, and the performance or certification level it has to meet. Typical options in this category include corona treated surface; width up to 3000 mm; custom printed up to 8 colours. Materials most often specified are Polypropylene, Polylactic Acid, Low Density Polyethylene, High Density Polyethylene, and the choice between them changes stiffness, temperature resistance, chemical behaviour and price.
In the marine and offshore sector the decision is usually driven by UV and salt resistance and impact strength, with buoyancy as a secondary requirement. Typical end uses include deck fittings, dock fenders, buoyancy floats.
The table below summarises the values that usually decide the material choice.
| Material | Density | Tensile strength | Service temperature |
|---|---|---|---|
| High Density Polyethylene | 0.94-0.97 g/cm³ | 20-32 MPa | -50°C to 80°C |
| Polylactic Acid | 1.24 g/cm³ | 50-60 MPa | up to 55°C (HDT) |
| Low Density Polyethylene | 0.91-0.93 g/cm³ | 8-20 MPa | -50°C to 70°C |
Polylactic Acid is frequently the default selection here: PLA is compostable in industrial facilities, not in a backyard heap, so label it carefully.
Polylactic Acid grades offer bio-based and industrially compostable, while Low Density Polyethylene brings very flexible and soft. For marine and offshore service the difference shows up in creep and in the long term behaviour under load.
In short: choose the first option when stiffness, heat and dimensional stability dominate; choose the second when impact, cost and processing speed matter more.
Beyond the base resin, most suppliers offer UV stabilised, food contact, flame retardant, anti-static and recycled content versions of the same product. Ask which additive package is included, because it is often the difference between a part that lasts three years and one that lasts ten.
The route below is the one most factories use for this type of part.
Secondary operations such as printing, welding, machining and assembly are often cheaper to do in the same factory, and they reduce the risk of mismatch between components.
Use this checklist when comparing two or three supplier quotations.
Send this list to your supplier with the drawing and you will receive comparable quotations from every factory you contact.
Yes. Standard samples are normally free of charge and shipped within three working days; custom samples are charged at cost and credited against the first production order.
A new tool typically takes 25 to 45 days depending on cavity count and complexity, followed by T1 samples within one week. Existing tools can usually start production within 10 to 15 days of order confirmation.
For standard sizes and colours the minimum is usually one pallet or one production run; for custom tooling the economic minimum depends on the tooling cost amortised over the expected volume. Send us your annual volume and we will calculate the break even point.
Colour is controlled with a masterbatch reference approved by the customer, and every production lot is checked against the approved sample under standard lighting before shipment.
Standard production tolerance follows the relevant ISO or DIN tolerance class for the process; tighter tolerances are possible after machining or grinding, but they add cost. Define the tolerance only on the functional dimensions.
If you are planning a new marine and offshore project, send us your drawing, annual volume and target properties, and we will come back with a material proposal, a tooling plan and a budget quotation.
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