Matsui Fixer WF-N | Eco-Friendly Wash Fastness Additive for Water-Based Screen Printing Ink

Matsui Fixer WF-N – The Wash Fastness Additive That Makes Your Water-Based Prints Last.

Every screen printer who has switched to water-based ink has asked the same question: will it hold up in the wash? The answer, when you add Matsui Fixer WF-N to your ink, is yes.

Fixer WF-N is a cross-linking agent. Its job is to strengthen the chemical bond between the ink and the garment fibers at a molecular level. When mixed into any Matsui water-based ink at 1-4% by weight, Fixer WF-N creates additional cross-links within the ink film during the curing process. These cross-links lock the ink into the fabric’s fiber structure, dramatically improving resistance to washing, rubbing, and color fading over time.

The result: prints that survive repeated machine wash cycles without cracking, peeling, fading, or losing vibrancy. This is not just about passing a wash test – it is about delivering production-grade durability that meets the same expectations your customers have for plastisol prints, using an environmentally safe, PVC-free water-based system.

How Cross-Linking Works – Why Fixer WF-N Improves Wash Fastness

Understanding the chemistry behind Fixer WF-N helps you use it effectively:

Water-based inks cure through evaporation and film formation. When the ink is heated, the water evaporates and the remaining resin forms a film that sits on and within the fabric fibers. Without a cross-linker, this film relies solely on mechanical adhesion – the dried ink physically grips the fibers, but the bond is not chemically reinforced.

When you add Fixer WF-N, the cross-linking agent reacts during the heat curing process to create chemical bonds between the resin molecules and between the ink and the fiber. These chemical bonds are significantly stronger than mechanical adhesion alone. The ink does not just sit on the fiber – it becomes chemically anchored to it.

This is why Fixer WF-N improves wash fastness, crock fastness (rub resistance), and overall print durability. The cross-linked ink film is tougher, more flexible, and more resistant to the mechanical agitation and detergent exposure that occurs during machine washing.

Matsui Fixer WF-N Key Features:

• Improves Wash Fastness: The primary function of Fixer WF-N. Cross-links the ink to garment fibers at the molecular level, ensuring prints survive repeated machine wash cycles without cracking, peeling, or fading.
• Lowers Cure Temperature by 20°F: Reduces the required cure temperature from 320°F (160°C) to 300°F (150°C). This gives printers more flexibility with heat-sensitive fabrics, reduces energy costs, and provides a wider margin of error on conveyor dryer settings.
• No Limited Pot Life: Unlike other fixers (Fixer WF-F and Fixer L, which both have a 24-hour pot life once mixed), Fixer WF-N does not expire once blended into your ink. Your mixed ink stays usable indefinitely – you can mix it in advance, store it, and use it across multiple print runs without waste.
• Eco-Friendly and Formaldehyde-Free: Clean, safe chemistry with no formaldehyde, no APEO, and no restricted substances. Fixer WF-N meets all RSLs (Restricted Substance Lists) of all major brands – a critical requirement for printers producing for retail, corporate, and branded merchandise.
• Low Dosage / High Impact: Only 1-4% by weight is needed to achieve a meaningful improvement in wash and crock fastness. A small amount goes a long way, keeping per-print additive costs extremely low.
• Universal Matsui Compatibility: Works with the entire Matsui water-based ink lineup – 301 RC Series, 301C Clear, Alpha Series, Infinity Series, Stretch, Simple, EasyPrint, Dye Blocker, Specialty Inks, and Discharge Inks. One additive covers your entire ink shelf.
• Improves Crock Fastness: In addition to wash durability, the cross-linking action improves resistance to rubbing and abrasion (crocking), which is especially important for printed athletic wear, workwear, and garments subject to friction.
• Does Not Affect Print Quality: At the recommended 1-4% dosage, Fixer WF-N does not alter ink color, opacity, hand feel, or printability. Your prints look and feel exactly the same – they just last longer.
• Easy Integration: Simply weigh and mix into your ink before printing. No special equipment, no additional steps in your workflow. Clean up with water and mild soap.

Why Screen Printers Use Matsui Fixer WF-N

Wash fastness is the number one concern screen printers hear from customers ordering water-based prints. Whether it is a gym owner ordering 500 branded tees, a streetwear brand launching a limited drop, or a corporate buyer sourcing employee apparel, the question is always the same: will this print last?

Fixer WF-N exists to give you a confident “yes” answer, backed by chemistry rather than hope.

The Real-World Problems Fixer WF-N Solves:

• Failing wash tests on retail orders. Major brands and retailers require prints to pass specific wash fastness standards before approving production. Adding Fixer WF-N to your ink is the fastest way to push your wash test results into the passing range without changing your ink system.
• Customer complaints about fading prints. If customers are coming back saying prints are fading or cracking after 10-20 washes, the ink-to-fiber bond is too weak. Fixer WF-N strengthens that bond to extend print life significantly.
• Printing on difficult fabrics. Blends, performance fabrics, and polyester-heavy garments can be challenging for water-based inks to grip. Cross-linking with Fixer WF-N improves adhesion on fabrics where mechanical bonding alone is insufficient.
• Electric dryer limitations. Electric conveyor dryers often struggle to reach or maintain the full 320°F cure temperature consistently, especially with multiple layers or heavy ink deposits. Fixer WF-N lowers your required cure temp to 300°F, giving your dryer a 20-degree cushion.
• Running discharge ink jobs. Discharge inks benefit significantly from Fixer WF-N because the discharged (bleached) fiber is more porous and the re-deposited color needs a strong cross-linked bond to maintain wash durability.
• High-volume production with pre-mixed ink. Because Fixer WF-N has no pot life limitation, you can pre-mix large batches with the fixer added and store them for future use. Other fixers with 24-hour pot lives force you to mix only what you will use that day, creating waste and disrupting workflow.

Fixer WF-N vs. Other Matsui Fixers – Which One Do You Need?

Matsui offers four different fixers, each designed for specific situations. Here is how they compare:

Bottom line: Fixer WF-N is the go-to fixer for most production environments. It gives you the best combination of wash fastness improvement, no pot life limitation, full RSL compliance, and formaldehyde-free safety. The only reasons to choose a different fixer are if you specifically need air-dry curing (Fixer L), the absolute lowest cure temperature at 250°F (Fixer WF-F, with trade-offs), or you are printing with polyurethane binder inks (Fixer V).

Compatible Matsui Ink Systems:

Fixer WF-N works across the full range of Matsui water-based ink products:

How to Use Matsui Fixer WF-N

Step 1 – Weigh Your Ink: Place your mixed Matsui ink on a scale and record the weight. You will need this to calculate the correct percentage of Fixer WF-N.

Step 2 – Calculate the Dosage: Add Fixer WF-N at 1-4% by weight. For most standard production jobs, 2-3% is the sweet spot. For discharge inks and high-wash-demand garments, go toward the upper end of the range.

Step 3 – Mix Thoroughly: Using clean mixing utensils, blend the Fixer WF-N into your ink until it is completely and evenly distributed. Ensure there are no pockets of unmixed fixer.

Step 4 – Print Normally: No changes to your print process are needed. Squeegee pressure, stroke count, mesh selection – everything stays the same. Fixer WF-N does not alter viscosity, opacity, or printability.

Step 5 – Cure at 300°F (150°C) or Higher: With Fixer WF-N mixed in, your minimum cure temperature drops from 320°F to 300°F. Maintain your standard dryer dwell time of 120 seconds (2 minutes). If your dryer is already running at 320°F, there is no need to lower it – the cross-linking will still activate.

Step 6 – Wash Test: Always perform a wash test before running a full production order. Wash and dry the test print 3-5 times and inspect for color loss, cracking, or peeling. Adjust the Fixer WF-N percentage within the 1-4% range if needed.

Pro Tips for Best Results

• 2-3% is the production standard. Most experienced Matsui printers settle on 2-3% Fixer WF-N as their go-to dosage. 1% provides a mild improvement. 4% is for maximum durability on high-demand garments.
• Mix it into every batch as standard practice. Because Fixer WF-N has no pot life limitation, many production shops add it to every batch of ink they mix. There is no downside – only improved durability – and no risk of wasting ink due to expiration.
• Combine with Quick Additive if you want an all-in-one solution. Matsui Quick Additive (WB1028) already contains Fixer WF-N along with Retarder MG, Softener MG, and Thickener B. If you are already using Quick Additive at 7-9%, you may not need additional Fixer WF-N unless you want extra wash fastness beyond what Quick Additive provides.
• Essential for discharge printing. Discharged fibers are more porous than regular cotton because the original dye has been removed. The re-deposited color needs every advantage to grip those fibers, and cross-linking with Fixer WF-N provides exactly that.
• Use with electric dryers for extra insurance. Electric conveyor dryers can be inconsistent at reaching peak temperature. The 20°F cure reduction from Fixer WF-N gives you a safety margin that prevents undercured prints from reaching customers.
• Always use clean mixing vessels. Contamination from other ink sources or non-approved additives can compromise the cross-linking chemistry. Use dedicated, clean utensils every time.
• Always wash test before production. Every garment, every ink color, every mesh count can produce different results. A quick wash test with Fixer WF-N added takes 10 minutes and prevents returns.