Expertise in Spray Starch Application for Paper and Paperboard

Spraying Systems Co. brings decades of practical spray application expertise to the design, implementation, and optimization of spray starch systems for paper and paperboard manufacturing.

Spray starch can provide significant benefits, including improved plybond strength, enhanced sheet properties, reduced fiber costs, and better use of alternative starches. However, these benefits depend on more than starch selection alone. Successful results require precise spray placement, controlled droplet size, uniform cross-direction distribution, and reliable system performance in demanding papermaking environments.

We help mills bridge the gap between starch chemistry and machine operation by engineering spray systems that deliver starch accurately, consistently, and efficiently.

Why Spray Starch Requires Application Expertise

Spray starch technology sits between wet-end starch addition and size-press application. Instead of adding cooked starch to the wet end or applying starch at the size press, spray starch is applied as an uncooked or partially swollen starch suspension directly onto the wet web. The starch is retained in the sheet through filtration and then gelatinizes during drying to help develop fiber-to-fiber bonding.

While the concept is well established, mill-scale success depends heavily on the application process. Poor spray geometry, uneven coverage, droplet coalescence, nozzle plugging, or incorrect spray bar placement can reduce or eliminate the expected benefits.

Spraying Systems Co. specializes in this critical interface between chemistry and production. Our systems are designed to deliver starch uniformly, repeatably, and reliably under the thermal, hydraulic, and contamination challenges commonly found in papermaking operations.

Key Factors That Influence Spray Starch Performance

Retention and Distribution

When starch is sprayed onto the wet web, granules are retained primarily through filtration rather than adsorption. This allows up to 10-20% higher starch addition rates than typical wet-end cationic starch applications.

Retention and performance are strongly influenced by:

• Droplet size distribution
• Spray impact velocity
• Spray pattern uniformity
• Cross-direction coverage
• Starch solids and suspension stability

Uneven application can lead to localized over-bonding, under-bonding, streaking, and wasted starch. For this reason, precision spray system design is essential to consistent performance.

Gelatinization During Drying

For spray starch to contribute to sheet strength, starch granules must encounter the right combination of moisture, temperature, and time during drying. Spray bar location, penetration depth, and dryer conditions all affect whether the starch properly swells and bonds fibers or remains underutilized in the sheet.

Proper system design helps ensure that starch is placed where it can deliver the greatest value.

Application Configurations

Spray starch systems can be adapted to several paper and paperboard machine configurations. In each case, success depends on accurate placement, controlled penetration, and dependable spray performance.

Fourdrinier Machines

On Fourdrinier machines, the spray bar is typically positioned between the headbox and the wet line. The goal is to achieve controlled starch penetration without excessive migration.

Spraying Systems Co. systems may include:

• Fan-pattern nozzles with controlled overlap
• Cross-direction zoning for application control
• Heated and agitated starch delivery loops
• System designs that support uniform coverage and reduced plugging

Vat and Cylinder Board Machines

For vat and cylinder board applications, starch is often sprayed into the nip between partial plies. This allows targeted plybond improvement without unnecessary starch use in outer layers.

Spraying Systems Co. supports these applications through:

• Accurate targeting of the nip zone
• Nozzle placement that minimizes fiber buildup
• Stable spray patterns in challenging machine environments
• Practical support for startup and troubleshooting

Twin-Wire Formers

On twin-wire machines, spray beams are typically positioned ahead of the nip to support controlled starch entrapment and z-direction distribution. Because migration risk can be higher in these applications, droplet size control and spray penetration management are especially important.

Supporting Mill Performance Goals

Spray starch can support a range of mill objectives, including strength improvement, fiber optimization, cost reduction, and sustainability initiatives.

Plybond and Strength Development

Research and mill experience show that spray starch can improve plybond and strength properties when application and drying conditions are properly managed. Too much starch, uneven distribution, or overly aggressive drying can limit performance.

Spraying Systems Co. helps reduce these risks by engineering systems for:

• Uniform cross-direction distribution
• Predictable application rates
• Consistent spray quality
• Compatibility with machine-specific drying strategies

Alternative Starches and Sustainability

Alternative starches, such as pea starch and other nontraditional sources, may offer performance or sustainability advantages. However, these materials can behave differently from conventional starches in terms of rheology, solids content, gelatinization temperature, and handling characteristics.

Our spray systems can be designed to accommodate these differences, helping mills evaluate and implement alternative starches with greater confidence.

Integration with Modern Filler Strategies

Starch-modified fillers and related technologies also depend on proper placement and distribution within the sheet. Whether the application involves starch, starch-coated fillers, or other functional additives, the same spray fundamentals apply: droplet control, uniformity, clean operation, and maintainability.

Why Spraying Systems Co.

Our value comes from combining spray technology, process knowledge, and hands-on papermaking experience. We provide:

• Decades of pulp and paper spray application expertise
• Proven nozzle designs for challenging operating environments
• Spray headers and control strategies for uniform application
• Heated, agitated, and recirculated delivery system options
• Application support for startup, optimization, and troubleshooting
• Practical engineering focused on mill-scale results

Beyond equipment, Spraying Systems Co. supports spray starch applications with local technical service, OEM and engineering collaboration, custom fabrication capabilities, and sustainability-focused solutions. Our spray experts help evaluate application conditions, specify systems for unique production requirements, design custom headers and manifolds, and improve efficiency to help reduce starch waste, energy use, water use, and fiber costs.

Spray starch success is not accidental. It is engineered.

Conclusion

Spray starch application is a powerful tool for improving paper and paperboard strength while supporting cost, productivity, and sustainability goals. The potential is well documented, but performance depends on reliable and precise application.

Spraying Systems Co. helps mills convert spray starch potential into measurable results through engineered spray technology, application expertise, and practical on-machine support.

Where starch chemistry meets machine reality, Spraying Systems Co. delivers the difference and helps customers Make Every Drop Count.