Post-industrial plastic waste: classification by resin and value as raw material

What is usually thrown away has another name: secondary raw material

Every manufacturing plant generates leftovers: sheet trimmings, parts rejected during quality control, injection sprues, molding flash, defective film rolls. For many production managers, this is simply garbage, and they treat it as such: they pay for its disposal or let it pile up until it becomes a space problem. What is not always known is that this material has a technical name—post-industrial plastic waste—and, depending on its type and condition, it has a concrete commercial value as a secondary raw material.

Understanding the difference between the various types of plastic waste, learning to identify the resin they are made of, and knowing what makes one batch worth more or less than another is the starting point for turning a cost into revenue.

Post-industrial waste versus post-consumer waste: they are not the same thing

The distinction matters because it defines the quality of the material and the process it requires to be reincorporated into the production chain.

Post-industrial plastic waste is generated within the manufacturing process, before the product reaches the consumer. Typical examples: extrusion trimmings, thermoforming scraps, out-of-spec parts, machine purges. This material has generally not been in contact with the end user, its composition is known—the plant knows exactly which resin it used—it is relatively clean, and it is usually a single resin with no blending. That is why it is the highest-value waste in the secondary market: it requires less processing to become raw material again.

Post-consumer plastic waste is what arrives after a product has completed its use cycle: bottles, containers, bags, toys, discarded appliance parts. Here the challenge is greater: the material may be contaminated, mixed with other resins, labeled with adhesives, or combined with other materials. Its value is real, but the recovery process requires more sorting, washing, and processing steps.

A company that generates scraps in its plant is producing post-industrial waste, which is precisely the type of material most in demand by recycling companies.

How plastics are classified by resin type

The factor that most determines the value and recyclability of a plastic waste is the resin it is made from. Plastics are not a single material: they are families of polymers with very different physical and chemical properties. Mixing them without sorting is the equivalent of mixing aluminum with iron: the result is useless.

The most widely used identification system is the resin code, which appears on many products as a number inside a triangle. These are the resins most commonly found in Dominican industry:

PET — Polyethylene terephthalate (code 1)

This is the resin used for water and soda bottles, but it also appears in food containers, trays, and textile fibers. In post-industrial form—sheet trimmings, blow-molding rejects—it is a highly valued material because it can be reprocessed into fiber, strapping, or preforms. Its high melting point and transparency make it easy to identify.

HDPE — High-density polyethylene (code 2)

Found in buckets, detergent containers, pipes, caps, and heavy-duty bags. It is one of the most recycled materials on the market because it is rigid, relatively easy to clean, and retains good mechanical properties after reprocessing. Post-industrial HDPE scrap—pipe trimmings, injection-molded parts—is in high demand.

PVC — Polyvinyl chloride (code 3)

Present in pipes, window profiles, vinyl flooring, hoses, and cables. It is recyclable, but requires special care because improper reprocessing can release chlorine, making it less accepted than other resins. Its recovery is possible but depends on the condition and purity of the batch.

LDPE — Low-density polyethylene (code 4)

This is the resin used for flexible plastic bags, packaging films, stretch film, and coatings. In industry it is generated as scrap in defective rolls, sealing trimmings, or film remnants. Its recycling produces pellets that are reused in bags or lower-demand sheeting.

PP — Polypropylene (code 5)

Very versatile: found in food containers, caps, automotive parts, raffia, chairs, and technical fabrics. PP scrap—injection flash, rejected parts, broken strapping—is one of the most valued because reprocessed polypropylene retains good properties and has a broad market in regional manufacturing.

PS — Polystyrene (code 6)

Includes expanded polystyrene (styrofoam) and standard polystyrene. Found in packaging boxes, disposable cups, and supermarket trays. Recycling exists but is more complex, especially in expanded form due to the material's low density.

Other (code 7)

Encompasses less common resins such as ABS, polycarbonate, nylon, or blends. They have specific secondary markets, but require precise identification for recovery.

What factors determine the value of plastic waste

Not all batches of the same resin are worth the same. There are variables that raise or lower the price a recycler can pay:

• Resin purity: a batch of PP with no admixture of other plastics is worth considerably more than one contaminated with PE or PVC. Each additional resin in the mix complicates reprocessing and degrades the properties of the final product.
• Cleanliness level: clean post-industrial scrap—free of oils, dirt, and labels—requires less processing. Dirty material may not even be accepted if the cost of washing it exceeds its value.
• Form of the material: large or irregular pieces must be ground before processing, which has a cost. Already ground or granulated material facilitates the process and may have higher value.
• Volume and consistency: a generator that can offer regular, consistent volumes of the same material is in a better position to negotiate favorable terms than one that generates small, irregular batches.
• Color: transparent or natural material is worth more than pigmented material because it allows greater flexibility in reprocessing. Black material has the lowest value because it cannot be lightened.

Why it makes sense to sort at the source

The most common mistake in plants is accumulating all plastic waste in a single container. When a recycler receives that mixed material, the price it can pay is that of the lowest-quality material, because the cost of separating it falls on them. In contrast, a company that sorts at the source—HDPE in one container, PP in another, film in another—delivers a higher-value product and simplifies collection logistics.

Implementing that separation does not require a major investment: in many cases it is enough to define color-coded or labeled containers and briefly train operational staff on what goes in each one. The return comes in the form of a better price for the material or, depending on the volume, free collection arrangements.

Sorting also facilitates compliance with environmental regulations, which in the Dominican Republic—as in the rest of the region—increasingly require documentation on the handling of industrial waste.

The current state of the secondary plastics market

Regulatory pressure on the use of virgin plastic has increased in recent years in markets such as Europe and the United States, which raises demand for recycled material from manufacturers that need to meet minimum recycled content requirements in their products. This has a direct effect on the price of secondary resins: recycled raw material no longer competes on price alone—in some sectors it is the only way to access certain export markets.

For Dominican companies that generate plastic scrap, this means there are active buyers for this material and that the market is not purely local.

How Scrapmen Recycling Group works with industrial generators

At Scrapmen Recycling Group we buy, process, and recover post-industrial and post-consumer plastic waste in the Dominican Republic. If your company generates plastic scraps, trimmings, rejects, or out-of-spec parts and is currently discarding them as costly waste, we can evaluate that material, identify its resin, and offer you a purchase or collection solution. The goal is for what is today a disposal cost to become revenue or at least zero cost for your operation.

If you are not sure what type of resin your plant generates or how to sort it, we can also guide you through that process.

Frequently asked questions

How can I identify which resin the plastic my plant generates is made of if I am not certain?

The starting point is the resin code that appears on products or on the technical data sheets of the material you purchase from your supplier. If your plant uses pellets or sheeting from a single supplier, they should be able to tell you exactly which resin you are using. If in doubt, an experienced recycler can help you identify the material with basic tests—such as heat behavior or density—before deciding how to sort it.

Is it worth sorting if the volume I generate is small?

It depends on the type of resin and how frequently it is generated. Some resins have enough value to justify sorting even in moderate volumes. The most useful step is to speak with the recycler before discarding it: in many cases material that seems of little relevance can find a buyer if it is properly sorted and clean. Accumulating material over a period of time can also be an option to reach volumes that make collection more efficient.

Does mixed or dirty material have no value at all?

Not necessarily, but its value is lower and in some cases it may not be accepted if the cost of processing it exceeds what can be recovered. Cleanliness and resin purity are the factors that most affect the price. That is why sorting at the source—even into just two or three basic categories—always improves the economic outcome for the generator.