Ancillary Equipment

Silicone Rubber Separator for Plastic Flake Purification

A silicone rubber separator removes soft silicone, rubber and elastomer particles from rigid plastic regrind so the cleaned flake can be sold or compounded as high-purity ABS, PS, PP or PC. Rumtoo uses a friction-and-elasticity spindle deck — rigid flakes slide forward and discharge clean, while elastic rubber grips the rollers and migrates to a separate outlet, typically leaving below 2% rubber residue.

  • Matched to your feedstock and output target
  • Stable throughput with controlled discharge size
  • Layout, controls, and service support customized
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Silicone Rubber Separator for plastic flake purification
  • Matched to your feedstock and output target
  • Stable throughput with controlled discharge size
  • Layout, controls, and service support customized

Backed by Documented Performance Targets

CE Certified Manufacturing
24/7 Global Technical Support
12-Month Comprehensive Warranty
Turnkey Installation & Training

How Friction-and-Elasticity Separation Works

The separator exploits one simple physical difference: rubber and silicone are elastic and high-friction, while rigid plastic is hard and low-friction. These four steps are what a stable, repeatable cut depends on.

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Step 1 — Spread the feed to a monolayer

Vibration discs distribute incoming flake across the full deck width as a single-particle layer. A piled or uneven feed is the most common cause of poor separation, so feed-rate control matters as much as the deck itself.

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Step 2 — Drive the friction spindles

Four 375 mm spindles rotate at a set speed. Rigid plastic flakes have low surface friction and slide forward along the spindle axis; elastic rubber and silicone particles grip the rotating surface and are carried transversely toward the rubber outlet.

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Step 3 — Tune the cut point

Spindle speed and deck inclination set where the rigid-vs-elastic boundary falls. Walk the settings while sampling both outputs until rubber residue in the clean fraction drops to target without losing too much good flake to the reject.

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Step 4 — Recirculate the reject

The rubber-rich fraction still carries some rigid flake. A second pass through the separator recovers that flake and tightens the rubber concentration in the final reject, improving overall yield.

Why a Dedicated Separator, Not Just Density Sorting

Silicone and many rubbers sit close to common plastics in density, so a sink-float tank cannot reliably split them. A friction-and-elasticity deck separates on a property that density sorting ignores.

Separates What Density Cannot

Silicone (~1.1–1.2 g/cm³) overlaps with ABS, PS and PET, so float-sink leaves it behind. Friction-and-elasticity sorting targets elasticity and surface friction instead, catching rubber a density tank misses.

Dry, Chemical-Free Process

No water, solvents or heat — just mechanical action. That means no wastewater to treat, no drying step afterward, and no risk of thermally degrading the plastic.

Turns Mixed Scrap Into Prime

Dropping rubber residue below ~2% is often the difference between selling regrind as low-value mixed scrap and selling it as prime single-resin flake at a far higher price.

Troubleshooting & Operating Reference

These are the issues that most often pull a silicone rubber separator off target. Each has a concrete first thing to check before anything else.

Problem

Rubber residue in the clean fraction is too high.

Rumtoo Solution

Check the feed layer first — a piled feed defeats the friction cut. Then reduce feed rate, lower the deck speed slightly so elastic particles have more time to grip, and confirm the flake is dry. Wet or dusty flake masks the friction difference.

Problem

Too much good plastic ends up in the rubber reject.

Rumtoo Solution

The cut is set too aggressively. Raise the deck angle or spindle speed in small steps, and run the reject through a second pass — most carried-over rigid flake is recoverable on a re-feed without loosening the main cut.

Problem

Separation drifts over a shift with no setting change.

Rumtoo Solution

Usually a feed-property change: a new batch with different flake size, moisture, or rubber type. Re-sample the feed and re-walk the cut point. Worn spindle surfaces also reduce grip over time — inspect and resurface on schedule.

Problem

Fine dust is clogging the deck and outlets.

Rumtoo Solution

Add or restore upstream de-dusting. Fines bridge the friction gap between rigid and elastic particles and coat the spindles, flattening the separation. A clean, screened feed is part of the separation system, not an optional extra.

Where the Separator Sits in a Plastic Recycling Line

A silicone rubber separator is a polishing stage, not a primary process. It belongs after granulation and washing, on dry flake, and before pelletizing — the point where a small percentage of rubber contamination decides whether your regrind sells as prime or as mixed scrap.

Friction spindle deck of a silicone rubber separator

Equipment View: Friction-and-Elasticity Spindle Deck

Dry flake is spread into a thin, even layer by vibratory feeders, then carried across a deck of four rotating 375 mm spindles. Rigid plastic flakes slide and bounce forward to the clean discharge; elastic silicone and rubber particles grip the spindle surface and are carried off to a separate rubber-rich outlet. The separation is purely mechanical — no water, no chemicals, no heat.

  • Four 375 mm friction spindles driven by two 3 kW main motors
  • Vibration discs spread the feed to a monolayer for stable separation
  • Adjustable spindle speed and deck angle tune the rigid-vs-elastic cut point

Process View: After Washing, Before Pelletizing

In a typical Rumtoo line, material moves: shredder → granulator → washing/drying → silicone rubber separator → pelletizer. Placing the separator on clean, dry flake — not on wet or dusty material — is what makes the rubber-residue numbers achievable. A second pass on the rubber-rich fraction recovers any rigid flake carried over.

  • Runs on dry flake; surface moisture and fines degrade the friction cut
  • Rubber-rich reject can be re-fed for a second pass to recover good flake
  • Clean flake discharges straight into a pelletizing or bagging stage
Silicone rubber separator position in a plastic recycling line

Silicone Rubber Separator in Operation

See how rigid plastic flake discharges clean off the spindle deck while elastic silicone and rubber are carried to a separate outlet.

Silicone & Rubber Separation Applications

These are the streams where removing the last few percent of rubber unlocks the value of an otherwise clean plastic fraction.

  • WEEE & E-Waste Plastics

    Removes rubber feet, gaskets, silicone seals and elastomer keypads left in shredded electronics plastic, lifting ABS/HIPS regrind to prime purity.

  • ELV / Automotive Plastics

    Strips rubber trim, weatherstrip and silicone hose fragments from end-of-life-vehicle plastic so the PP and ABS fractions meet compounder specs.

  • Cable & Wire Regrind

    After copper recovery, the leftover jacket regrind often mixes rigid PVC/PE with rubber and silicone insulation — the separator splits them for clean resale.

  • Injection-Molding Regrind

    Cleans rubber over-mold and silicone gasket contamination out of reground ABS, PC and PP parts before they re-enter the molding feed.

  • Medical & IV Bottle Scrap

    Separates rubber stoppers and silicone components from PP/PE bottle regrind in pharmaceutical and IV-bottle recycling streams.

  • Mixed Crushed Sponge, Rubber & Plastic

    For post-crush streams where sponge, rubber and plastic arrive mixed together, the separator pulls the elastic fraction out to raise recycling value.

Silicone Rubber Separator Specifications

Three standard models from 1 to 3 t/h. Output purity depends on flake size, dryness, rubber type and feed rate — Rumtoo confirms targets in writing after testing your actual material.

ModelThroughput (t/h)Power (kW)Dimensions L×W×H (mm)ConstructionConfiguration
RTM1500S1–1.56.722150 × 2200 × 4300SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 4 × 90 W vibration discs · 4 × 90 W integrated units
RTM3000S1.5–27.082450 × 2200 × 4300SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 8 × 90 W vibration discs · 4 × 90 W integrated units
RTM4000S2–37.402950 × 2200 × 4950SS 201 + A3 steel4 × 375 mm spindles · 2 × 3 kW main motors · 8 × 90 W vibration discs · 4 × 90 W integrated units

Material-contact parts are stainless steel 201; the frame is A3 carbon steel. Throughput assumes dry, pre-screened single-resin flake. Heavily contaminated or mixed-size feed runs slower, and a second pass on the reject is recommended where rubber residue below 2% is required.

RFQ Checklist — What We Need to Size Your Separator

These inputs are enough to recommend a model, confirm an achievable rubber-residue target, and quote the right feed and discharge integration.

  1. Base Plastic & Rubber Type

    Tell us the rigid resin (ABS, PS, PP, PC, PVC, PE) and the contaminant — silicone, EPDM, NBR, natural rubber or sponge. Elasticity and friction differ by rubber type and change the cut.

  2. Current & Target Rubber Content

    Approximate rubber percentage in the feed now, and the maximum residue your buyer or compounder will accept (e.g. below 2%).

  3. Flake Size & Dryness

    Granulated flake size range and whether the material is washed and dried. Friction separation needs dry, screened flake to perform.

  4. Throughput & Operating Hours

    Average and peak t/h plus hours per day, so we size between the RTM1500S, RTM3000S and RTM4000S with margin.

  5. Upstream & Downstream Stages

    What feeds the separator (granulator, washing line, de-duster) and what follows (pelletizer, bagging, further sorting) — so feed and discharge heights match your line.

  6. A Representative Sample

    The single most useful input. A few kilograms of your real feed lets us run a trial, measure achievable residue, and commit to a number rather than estimate one.

Silicone Rubber Separator vs Other Sorting Methods

Why a friction-and-elasticity deck is the right tool for rubber-in-plastic contamination, compared with the alternatives a recycler might reach for.

MethodWhat It Sorts OnLimitation for Rubber-in-Plastic
Sink-float / density tankDensity difference in waterSilicone and many rubbers overlap common plastics in density, so they will not reliably float or sink apart
Electrostatic separatorSurface charge / conductivityWorks for some polymer pairs but is inconsistent on rubber-vs-plastic and needs very dry, fine, single-size feed
Manual / optical pickingColor and visual cuesRubber and plastic often share color; slow and labor-intensive at flake scale
Friction-and-elasticity separatorElasticity and surface frictionTargets the exact property that distinguishes rubber from rigid plastic — dry, chemical-free, and tunable to a residue target

Frequently Asked Questions

What does a silicone rubber separator actually remove?

It removes soft, elastic contaminants — silicone, vulcanized rubber, EPDM, NBR, natural rubber and sponge — from rigid plastic regrind. The goal is a clean single-resin flake (ABS, PS, PP, PC, etc.) with rubber residue typically below 2%.

How is it different from a sink-float tank?

A sink-float tank sorts by density in water. Silicone and many rubbers have densities close to common plastics, so they do not separate cleanly by flotation. The friction-and-elasticity separator sorts on elasticity and surface friction instead, which is a reliable property difference between rubber and rigid plastic.

What rubber residue level can it reach?

On dry, pre-screened, single-resin flake, below 2% rubber residue is a realistic target, and a second pass on the reject can push it lower. Actual results depend on flake size, rubber type and feed rate, which is why we test your material before committing to a number.

Does the material need to be washed and dried first?

Yes. Friction separation relies on the surface-friction difference between rubber and plastic, and surface moisture or dust masks it. The separator belongs after washing and drying, on clean dry flake, for stable results.

Which models are available and what is the throughput?

Three standard models: RTM1500S (1–1.5 t/h), RTM3000S (1.5–2 t/h) and RTM4000S (2–3 t/h). All use four 375 mm spindles and two 3 kW main motors, differing in vibration-disc count and frame size. We size the model to your throughput with margin for surge.

Can I send a sample to confirm it works on my material?

Yes, and we recommend it. A few kilograms of your real feed lets us run a separation trial, measure the achievable rubber residue, and quote against a tested result rather than an estimate.

Get a Silicone Rubber Separator Proposal

Share your base plastic, rubber type, current and target residue, and throughput. Rumtoo will recommend a model, run a trial on your sample, and return a proposal with a tested rubber-residue target.

Expert response within 24 hours. No obligation quote.