Matsui Retarder SP-1 Flow Additive | Improve Flow of Thick Water-Based Inks for Smoother Screen Printing
Matsui
Matsui Retarder SP-1 Flow Additive — Retarder SP-1 / Flow Additive improves the flow and leveling characteristics of thick, high-viscosity water-based inks without substantially reducing their viscosity. It is the correct solution when a heavy-body ink has proper thickness for the job but does not flow or level well under the squeegee — creating uneven coverage or difficult printing.
🎯 Problem it solves: Thick, heavy-body inks with poor flow on press — uneven ink distribution, drag, and difficult squeegeeing — without significantly reducing viscosity.
💊 Dosage: Per manufacturer specification — start low and test
✓Per manufacturer specification — start low and test
✓Matsui Acrylic Inks Compatible
✓PVC-Free
✓OEKO-TEX® Certified
🚚 FREE Shipping on orders over $200|📦 In-Stock: Usually ships same or next business day|🏪 Free In-Store Pickup · San Antonio, TX
Price range: $129.99 through $499.99
Description
Matsui Retarder SP-1 Flow Additive
Retarder SP-1 / Flow Additive improves the flow and leveling characteristics of thick, high-viscosity water-based inks without substantially reducing their viscosity. It is the correct solution when a heavy-body ink has proper thickness for the job but does not flow or level well under the squeegee — creating uneven coverage or difficult printing.
What It Does
🌊
Improves Flow
Enhances the ink’s ability to flow and spread under squeegee pressure — reducing drag and creating more uniform ink distribution across the print area.
📐
Improves Leveling
Helps the deposited ink film level out more evenly after the squeegee pass — reducing track lines and producing smoother, more consistent surface appearance.
⚖️
Maintains Viscosity
Unlike RV Additive, Flow Additive improves flow characteristics without significantly thinning the ink. The ink body is preserved while printability is improved.
When to Use This Additive
For thick inks, heavy-body mixing bases, or high-pigment-load inks that print stiffly or with poor coverage uniformity despite correct viscosity. Particularly useful for thick specialty bases (puff, etc.) and high-opacity formulations.
💊 Dosage
Per manufacturer specification — start low and test
✅ Compatible Inks
All Matsui water-based inks. Particularly useful with high-viscosity specialty bases.
⚠️ Limits
Start low and test — dosage varies by application. Keep total additives under 15%.
The Complete Matsui Additive Lineup — All 13
Every water-based printing problem has an additive that fixes it. Here is the full lineup with dosages and what each solves:
| Additive | Dosage | What It Solves |
|---|---|---|
| Quick Additive | 6–9% | All-in-one: open time + wash fastness + soft hand. Best starting point for most jobs. |
| Retarder MG | 1–5% | Prevents ink drying in screen. Extends open time on press. |
| Fixer WF-N | 1–5% | Improves wash fastness. Lowers cure temp to 300°F (150°C). Most common fixer. |
| Softener MG | 1–4% | Improves fabric penetration. Softer hand feel and better adhesion. |
| RV Additive | 1–3% | Reduces viscosity without weakening resin. Better flow and fabric penetration. |
| Thickener B | 0.25–1% | Increases viscosity. Controls halftone dot spread. Fine-detail work. |
| Fixer L | 1–3% | Lowers cure temp to 250°F. For electric dryers or heat-sensitive fabrics. |
| Fixer V | 2–3% | ⚠️ For PU binder inks ONLY (Soft-Tex 350 series). NOT interchangeable with Fixer WF-N. |
| Retarder SP-1 / Flow ← This Product | Varies | Improves flow of thick inks without reducing viscosity. For high-viscosity bases. |
| Emacol R-600-E | Varies | Long-bodied thickener for halftone dot retention. Alternative to Thickener B. |
| Puff Foaming Base HT | Varies | Creates 3D puff effect when flash-heated. Mix with any water-based ink. |
| Phantom Clear | Standalone | Disappears when dry. Reappears when wet (sweat). For activewear specialty prints. |
| Discharge Activator | 3–8% | ⚠️ REQUIRED for discharge mode. Enables chemistry on dark 100% cotton. 12-hr pot life. |
💡 Rule: Do not exceed 15% total additives in any ink batch. Complete additive guide with dosage charts, stacking rules, and FAQ →
Questions about which additive to use?
Call us at (512) 454-0505 Mon–Fri 9am–5pm CT
Technical Specifications
| Specification | Detail |
|---|---|
| Product Name | Matsui Retarder SP-1 Flow Additive |
| SKU | Matsui Flow Additive |
| Type | Improve Flow of Thick Water-Based Inks for Smoother Screen Printing |
| Dosage | Per manufacturer specification — start low and test |
| Problem Solved | Thick, heavy-body inks with poor flow on press — uneven ink distribution, drag, and difficult squeegeeing — without significantly reducing viscosity. |
| Compatible Inks | All Matsui water-based inks. Particularly useful with high-viscosity specialty bases. |
| Limits | Start low and test — dosage varies by application. Keep total additives under 15%. |
| Available Sizes | Quart, Gallon |
| Formulation | PVC-free, OEKO-TEX® Standard 100 certified |
| Storage | 65°F to 95°F (18°C to 35°C). Avoid direct sunlight. |
| Cleanup | Water and mild soap/detergent |
Technical Sheets / Safety Data Sheets / Documents
FREQUENTLY ASKED QUESTIONS
What is the difference between Flow Additive and RV Additive?
RV Additive reduces viscosity (thins the ink). Flow Additive improves flow and leveling characteristics without significantly reducing viscosity. Use RV Additive when the ink is simply too thick. Use Flow Additive when the ink has correct viscosity but poor flow or uneven coverage.
Can I use Flow Additive with RV Additive?
Yes — for inks that are both too thick AND have poor flow, use both. Add RV Additive to bring viscosity down, then Flow Additive to optimize flow characteristics. Test the combination.
Questions about which additive to use?
Call us at (512) 454-0505 Mon–Fri 9am–5pm CT
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