Matsui Kombat Blocker | Enhanced Water-Based Dye Migration Blocker for Sublimation-Printed Polyester — Part of the Kombat Performance Fabric System with Kombat White & Kombat Black

Benefits at a Glance

• Enhanced formula specifically for sublimation-printed polyester — the most aggressive dye migration challenge in screen printing
• Blocks sublimation dyes that re-activate at cure temperatures and migrate into overprint layers
• Part of the Kombat system with Kombat White and Kombat Black — complete performance fabric system
• Escalation beyond Blocker Gray and Blocker Black LG when standard blockers cannot contain sublimation dyes
• Also effective on standard dyed polyester — not limited to sublimation substrates
• Thick stencil recommended for maximum dye containment
• ⚠️ Pre-test on actual production fabric — 48-hour evaluation recommended
• Production-optimized with Matsui additives
• Zero viscosity modifications — prints from the container
• PVC-free and environmentally safe
• Essential for screen printing names, numbers, and logos over sublimation-printed team jerseys

Matsui WS0554 Kombat Blocker

What makes Kombat Blocker different from Blocker Gray and Blocker Black LG?

It has an enhanced formulation specifically improved for sublimation-printed fabrics. Blocker Gray handles standard dyed polyester. Blocker Black LG handles aggressively dyed polyester. Kombat Blocker is built for sublimation-printed polyester, which is the most aggressive dye migration scenario because sublimation dyes re-activate at cure temperatures and generate more migration pressure than standard garment dyes.

Why do sublimation-printed fabrics cause worse dye migration than standard dyed polyester?

Sublimation printing works by heat-activating dyes, meaning the dyes become gaseous at elevated temperatures. When you cure your screen print at 320°F, the sublimation dyes in the fabric begin re-activating at the bottom of their transition range and generate significant gaseous migration upward into your overprint layers. Standard garment dyes are heat-set and relatively stable at 320°F. Sublimation dyes are designed to mobilize at that temperature.

What is the Kombat system?

It is a three-product system for performance fabric printing: Kombat Blocker as the dye migration barrier, Kombat White as the bright elastic white with anti-foil properties, and Kombat Black as the deep black with excellent elasticity. The blocker goes first. The white and black print on top.

Can I use Kombat Blocker on standard dyed polyester, or only sublimation-printed?

Kombat Blocker is effective on both. It is enhanced for sublimation substrates, but it will also block standard polyester dye migration. If you are printing exclusively on standard dyed polyester, Blocker Gray or Blocker Black LG may be sufficient and more cost-effective.

Do I need to pre-test?

Yes — always. Dye migration varies across polyester types, dye lots, sublimation print densities, garment brands, and production batches. Print Kombat Blocker on a sample from the actual production fabric, flash it, overprint it, and cure it. Then wait 48 hours and check for migration. If the blocker holds, proceed to production.

Why wait 48 hours before evaluating the test?

Some dye migration is not immediately visible. Residual thermal energy continues driving dye movement after the garment exits the dryer. What looks clean at one hour may show visible migration at 24 to 48 hours. The 48-hour check helps catch delayed migration.

What mesh count should I use?

Up to 120/inch (47/cm). For the most aggressive sublimation prints, use 80–110 mesh for maximum blocker deposit. Lower mesh gives more deposit, and more deposit gives better dye containment. A thick stencil using capillary film or multiple emulsion coats will further increase deposit thickness.

What print sequence should I use on a sublimation-printed jersey?

Kombat Blocker → flash → Kombat White for white elements → flash → Kombat Black for black elements → flash → colors as needed → final cure at 320°F (160°C). The blocker always goes down first.

Can I print standard 301 Series inks over Kombat Blocker, or only Kombat White and Kombat Black?

You can print any Matsui water-based ink over the cured or flashed Kombat Blocker layer. The Kombat system using Kombat White and Kombat Black is optimized for performance fabrics, but standard 301 Series inks and whites also work over the blocker.

What additives should I use?

Use Retarder MG at 1–5% for open time, Fixer WF-N at 1–5% for wash fastness, Thickener B at 0.25–1% for deposit thickness, and RV Additive at 1–3% for viscosity reduction. Browse all Matsui additives here.

Why is this product drop-shipped from Matsui?

Kombat Blocker ships directly from Matsui in Gardena, California. Allow an additional 2–3 days for processing before your order ships.

Is Kombat Blocker safe?

Yes. It is PVC-free and environmentally safe.