Plastic regrind is one of the most useful — and most misunderstood — materials in a recycling operation. Get the quality right and it sells at a steady margin or feeds straight back into your own production. Get it wrong and it sits in a warehouse nobody will buy. This guide explains what plastic regrind is, how shredders and granulators actually produce it, how to judge its quality, and how HDPE, PP, PVC, and PET regrind differ in practice.
What Is Plastic Regrind?
Plastic regrind is clean plastic scrap that has been mechanically size-reduced into small, irregular flakes or granules so it can be remelted and reused. It comes from production scrap, rejected parts, purgings, trim, and post-consumer items that are ground down rather than melted into uniform pellets. The output keeps the original polymer’s properties, which is what makes regrind a direct, lower-cost substitute for virgin resin.
The key word is mecânico. Regrind is not chemically changed — it is the same polymer, just smaller. That keeps the cost and energy use low, but it also means contamination, moisture, and inconsistent particle size carry straight through to the next process. Quality control happens at the grinding stage, not after.
In short: Regrind is size-reduced plastic scrap ready for remelting. Its value depends almost entirely on how clean and how consistent it is.
Regrind vs. Virgin, Recycled Pellets, and PCR
Buyers often use these terms loosely, but they describe different things and command different prices. Regrind is the rawest recycled form: ground flake straight from the granulator. Recycled pellets are regrind that has been remelted and extruded into uniform pellets, which costs more to produce but feeds molding machines more reliably.
| Material | What It Is | Custo Relativo | Melhor para |
|---|---|---|---|
| Virgin resin | New polymer from petrochemicals | Highest | Tight-spec, food-contact, structural parts |
| Regrind (flake) | Ground scrap, not remelted | Mais baixo | Blending with virgin, non-critical parts |
| Recycled pellets | Regrind remelted and pelletized | Médio | Stable feeding on molding and extrusion lines |
| PCR | Post-consumer resin, often pelletized | Média–Alta | Brand sustainability targets, packaging |
Most processors blend regrind with virgin resin — often 10% to 30% — to cut material cost without changing part performance. If you want a drop-in feed instead of a blend, regrind usually needs one more step through a linha de peletização to become uniform pellets.
How Plastic Regrind Is Made
Plastic regrind is made by feeding scrap through a shredder and a granulator that cut the material down to a controlled flake size, then screening out fines and contamination. Bulky or thick scrap usually needs two stages of size reduction; clean, thin scrap can often go straight into a granulator. The three machines below each play a distinct role.
1. Shredding (Primary Size Reduction)
For lumps, pipes, drums, or baled scrap, a triturador de plástico tears the material into coarse pieces a few inches across. The low-speed, high-torque action handles bulky and contaminated feed that would jam a granulator. Shredding is the first stage, not the finished flake.
2. Granulating (Final Flake Sizing)
UM granulador de plástico turns shredded pieces — or clean thin scrap fed directly — into the uniform flake that buyers call regrind. A screen under the rotor sets the final particle size: material stays in the cutting chamber until it is small enough to pass through. Screen choice is the single biggest lever on regrind consistency, as covered in our guia de granulador de plástico.
3. Grinding and Pulverizing (Fine Output)
When an application needs powder rather than flake — rotomolding or some PVC compounding, for example — a plastic grinder or pulverizer takes regrind down to a fine particle. The difference between grinding and crushing matters here; our breakdown of PVC grinding vs. crushing explains when each fits.
What Determines Regrind Quality
Regrind quality comes down to four things: cleanliness, particle-size consistency, moisture, and polymer purity. A buyer pays for predictability — flake that melts the same way every batch. The table below shows what separates a premium grade from a discounted one.
| Quality Factor | High-Grade Regrind | Discounted Regrind |
|---|---|---|
| Contaminação | Single polymer, no metal, paper, or other resins | Mixed resins, fines, labels, dirt |
| Particle size | Uniform flake from a controlled screen | Wide spread, dust and oversize |
| Color | Sorted, consistent color | Mixed color, limits end use |
| Umidade | Dried, ready to feed | Wet, causes defects on remelt |
| Fonte | Known, traceable scrap stream | Unknown mixed loads |
Most of these are set at the grinding stage. A sharp granulator screen and good blade clearance produce even flake with few fines; worn knives produce dust and long strands that downgrade the whole lot. Upstream sorting and metal separation protect both the machine and the final purity.
Regrind by Material: HDPE, PP, PVC, and PET
Each polymer grinds and sells differently. The notes below cover the four most common regrind streams.
- HDPE reciclado — from bottles, drums, pipe, and crates. Tough and forgiving to grind; widely used in non-pressure pipe, lumber, and molded parts. Color sorting drives the price.
- PP reciclado — from caps, automotive trim, and woven bags. Grinds cleanly and blends well with virgin PP. Watch for mixed copolymer grades.
- PVC reciclado — from pipe, profile, and window scrap. Often ground or pulverized to powder for compounding. Heat-sensitive, so cutting must stay cool to avoid degradation.
- PET reciclado — usually called flake, from bottles and trays. The most spec-sensitive stream: moisture, IV value, and contamination decide whether it goes to fiber, strapping, or food-grade lines.
How Regrind Is Used and What It’s Worth
Regrind is worth the most when it goes straight back into the process that created the scrap — a closed loop with no transport or trading margin. Outside that, it sells into injection molding, extrusion, pipe, lumber, and compounding, either as flake or after pelletizing. Pricing tracks virgin resin but sits below it, and the gap widens or narrows with cleanliness, color, and how tightly the polymer is identified.
The practical takeaway for a recycler: the money is made at the grinder. Consistent flake from a well-specified shredding and granulating line sells at a premium and runs trouble-free in your own molding machines. For a full view of where regrind fits in a recycling plant, see our overview of máquinas de reciclagem de plástico.
Perguntas frequentes
Plastic regrind is clean plastic scrap that has been mechanically ground into small flakes or granules so it can be remelted and reused. It keeps the original polymer’s properties and serves as a lower-cost substitute for virgin resin, usually blended in at 10% to 30%.
Virgin plastic is new polymer made from petrochemicals and meets tight, consistent specs. Regrind is ground recycled scrap of the same polymer at a lower cost. Regrind can match virgin performance in many parts when it is clean and consistent, which is why most processors blend the two.
No. Regrind is ground flake straight from a granulator. Recycled pellets are regrind that has been remelted and extruded into uniform pellets. Pellets cost more to produce but feed molding and extrusion machines more reliably than loose flake.
Bulky scrap is first broken down in a shredder, then sized into uniform flake by a granulator with a screen that sets the particle size. Clean, thin scrap can feed a granulator directly. For powder output, a grinder or pulverizer takes the regrind down further.
Cleanliness, particle-size consistency, moisture, color, and polymer purity. Most of these are set at the grinding stage: a sharp granulator screen and correct blade clearance produce even flake with few fines, while worn knives create dust and oversize that downgrade the lot.
Yes, and most processors do. A blend of 10% to 30% clean regrind with virgin resin lowers material cost while holding part performance. The right ratio depends on the part’s spec, the polymer, and how clean and consistent the regrind is.
Producing consistent, sellable regrind starts with the right size-reduction line. Tell us your scrap type, volume, and target flake size, and our team will recommend the shredder, granulator, and screening setup that fits — explore our granulators or request a configuration.
