How Kady's Roto-Stator Technology Can Be Used to Disperse Two Inch Chunks of Rubber Quickly

Large rubber pieces are hard to process. Natural rubber and synthetics such as SBR, NBR, and polybutadiene are elastic, tough, and slow to break down in ordinary mixers. When the feed is two-inch chunks, plants often shred first, then mix for hours, then mill again. That extra handling raises heat, solvent loss, labor, and batch variation.

Kady International's high-speed Roto-Stator mills are built for this job. The same precision rotor-stator head used across Kady lab and production mills can take two-inch rubber chunks, fracture them, wet them, and turn them into a uniform dispersion in one vessel. Tip speeds reach 9,000 feet per minute. Cycle times are often measured in minutes, not hours.

Why Two-Inch Rubber Chunks Are Difficult

Rubber does not behave like a pigment or a mineral slurry. Several problems show up at once:

• High toughness. Low-energy blades stretch the polymer instead of breaking it.
• Poor circulation. Dense chunks sink and sit outside the mixing zone.
• Tack after wetting. Once solvent touches the surface, pieces stick to each other, the shaft, and the tank wall.
• Heat and solvent loss. Long cycles raise temperature and drive off solvent.
• Extra equipment. Pre-choppers, premix tanks, and secondary mills add steps and cleanup.

The result is long batch times, higher cost, and uneven particle size. Kady's Roto-Stator design attacks those problems at the head, not with extra machinery.

How Kady Roto-Stator Technology Works on Large Rubber Solids

A Kady mill pumps material through radial slots in a high-speed rotor and drives it into the staggered slots of a stationary stator. The gap is tight. The energy is concentrated. The action is impact and attrition, not only laminar shear.

On a two-inch rubber charge, the sequence is straightforward:

1. Intake. The rotor acts as a centrifugal pump. Auxiliary propellers above and below the head pull chunks and liquid into the working zone from both directions.
2. Acceleration. Rubber is forced through the rotor slots and thrown at tip speeds up to 9,000 FPM.
3. Impact fracture. High-velocity pieces strike the stator slots. The collision breaks elastic chunks into smaller fragments.
4. Attrition. Reduced pieces pass again through the narrow rotor-stator clearance. Fresh surface is exposed to solvent or vehicle on every pass.
5. Wetting and stability. Turbulence, hydraulic pressure, and localized cavitation wet the new surfaces quickly and limit re-agglomeration.

Because energy is high and localized, large pieces keep circulating until the batch is uniform. Short residence time limits heat rise. Jacketed vessels and cooled shafts can be added when the solvent system is sensitive.

What Plants Typically See

Results depend on rubber type, solvent, solids level, and target fineness. Across adhesives, coatings, sealants, and specialty solutions, Kady applications commonly show:

• Direct charging of chunks up to about 2 inches (50 mm) without a separate shredder in many formulas.
• Size reduction and dispersion in roughly 10 to 30 minutes.
• Progressive cut-down from large pieces to fine, process-ready particles in one tank.
• Fewer stages: wet-out, chopping, and dispersion in a single step instead of chop, premix, dissolve, and remill.
• Workable circulation even as viscosity climbs.

Kady also reports that the same rotor-stator geometry scales from lab mills to production units, so a trial on a Model L, LB, or LT2000 can map to plant equipment with less guesswork.

How This Compares with Conventional Equipment

Shorter cycles and fewer machines mean higher throughput, less energy per batch, simpler layout, and more consistent product.

Which Kady Mills Fit Rubber Dispersion

The Roto-Stator head is the same idea from lab to plant. Configurations that suit rubber work include:

• Lab mills such as the LT2000 top-entry and Model LB bottom-entry units for formula work and scale-up. Small batches, interchangeable heads, and results that track production geometry.
• Top-entry and bottom-entry production mills for batch work from a few gallons to large tanks. Bottom-entry designs help when heavy rubber tends to settle.
• Continuous-flow mills when volume is high and a defined or random path through the head is preferred.
• Options such as jacketed tanks, vacuum or pressure, variable-speed drives, sweep arms for thick batches, and wear-resistant materials.

Kady has manufactured this class of mill since 1949 in Scarborough, Maine. Units run in more than 40 countries on coatings, inks, adhesives, chemicals, and other fluid/solid jobs. Rubber-chunk dispersion is a natural use of the same high-energy head that already handles high-solids clay, TiO2, pigments, and emulsions.

Where Fast Rubber Dispersion Matters

• Rubber solutions and contact cements for adhesives and sealants
• Elastomeric binders and modifiers in coatings
• Specialty polymer solutions
• Reprocessing of rubber scrap into fine dispersions
• Early size reduction before compounding or masterbatch work

In each case the practical gain is the same: charge larger solids, skip extra chopping equipment when the formula allows, and finish the dispersion faster with better control of heat and particle size.

Prove It on Your Formula

Kady offers free testing. Send the rubber, the solvent or vehicle, and the target spec. The lab can show whether two-inch chunks can go straight into the mill, how long the cycle runs, and how temperature behaves. Those results transfer to production because the rotor-stator geometry and tip-speed approach stay consistent across the line.

For application review, a quote, or a test, contact Kady International:

30 Parkway Drive Scarborough, ME 04074 Phone: 207.883.4141 Email: This email address is being protected from spambots. You need JavaScript enabled to view it. Hours: Monday–Friday, 8 AM–5 PM

Two-inch rubber chunks do not have to force a multi-stage plant. Kady Roto-Stator technology puts impact, attrition, and strong circulation in one head so large solids can be fractured, wetted, and dispersed quickly.