StarColor SC8000 Water-Based Flexo Ink: Safe Printing Solution for Baby Diapers

Date：2025-10-13 14:37:03  from：StarColor Ink  

As baby diapers are worn 24 hours a day in direct contact with infants’ delicate skin, the surface printing must not only deliver bright, durable colors but also meet the highest standards of safety — non-irritating, migration-free, and environmentally friendly. StarColor has developed the SC8000 series of water-based flexo inks specifically for diaper substrates, offering low-sensitivity, high-adhesion, and eco-safe performance. This series has been successfully adopted by leading diaper manufacturers across China, helping ensure product safety and compliance.

Industry Challenges: Safety and Quality Issues in Diaper Printing

Baby diaper printing involves complex substrates such as nonwoven fabrics (topsheet and waistband) and PE breathable films (backsheet). These materials are closely linked to infant skin, and conventional inks struggle to meet safety and adhesion requirements:

1. Safety Risks: Solvent-based inks often contain benzene and ester residues, releasing a strong odor after printing. Contact with these residues may cause skin irritation or diaper rash, violating the hygiene requirements of GB 15979-2021, which mandates “no odor, no irritation.”
2. Poor Adhesion and Durability: Nonwoven fabrics have loose fibers, while PE films have low surface energy (28–30 dyn/cm). Traditional water-based inks suffer from blurry prints, poor adhesion, and color fading during wear. Friction on waistband markings can cause peeling, and moisture from urine may lead to ink smearing or even flaking, posing ingestion risks for infants.
3. Environmental vs. Efficiency Dilemma: Solvent inks contain VOCs of 280–320 g/L and require costly exhaust treatment systems. They also dry slowly (5 seconds at 60°C), limiting compatibility with high-speed diaper lines (200–300 pcs/min).

StarColor’s Solution: Customized Water-Based Flexo Ink for Diaper Applications

To address these challenges, StarColor optimized both ink formulation and process parameters, launching the SC8000 series water-based flexo ink tailored for baby diaper printing.

1. Safer Ink Composition

• Hypoallergenic and Non-Irritating: Formulated with medical-grade acrylic–polyurethane resin (compliant with FDA 21 CFR 176.170) and deionized water as the primary solvent, VOCs ≤30 g/L. The printed diapers are completely odor-free. Third-party ISO 10993-10 skin irritation tests confirm a 0% sensitization rate, ensuring “zero irritation.”
• High Adhesion and Rub Resistance: A 1.8% diaper-specific adhesion promoter forms an “anchored bonding” structure on nonwovens, achieving 5B adhesion grade. On PE films, with low-temperature plasma pretreatment, rub resistance exceeds 600 cycles (500g load) with no color fading after 72 hours of wear.
• Moisture and Urine Resistance: Hydrophobic-modified monomers increase contact angle to 90°, preventing smudging or ink migration even under moisture, without affecting PE film breathability (WVTR ≥ 3000 g/(㎡·24h)).

2. No Equipment Modification Required

Most diaper production lines use high-speed flexographic presses (up to 250 pcs/min). StarColor provides optimized process parameters to ensure full compatibility:

• Substrate Pretreatment: PE films undergo low-temperature plasma treatment to raise surface energy to 36 dyn/cm, ensuring ink wettability. Nonwovens require no additional treatment.
• Printing Parameters: Use high-line anilox rollers for ink thickness control (6–8 μm). Squeegee hardness: 65 Shore A; printing pressure: 1.0–1.2 bar to prevent substrate deformation.
• Drying Optimization: Two-stage hot air drying (50°C, 2 m/s) completes within 1.5 seconds, supporting 300 pcs/min speed without wet stacking or sticking issues.

Case Study: Safety Upgrade for a Leading Diaper Manufacturer

Background: From Customer Complaints to Quality Improvement

A well-known baby care brand in Fujian, producing over 100 million diapers annually, faced frequent complaints about color fading and odor when using solvent-based inks. The VOC emissions exceeded environmental limits, and the local authority demanded rectification to avoid production suspension.

Results: Safety, Quality, and Efficiency Achieved

• Safety Compliance: Diapers printed with SC8000 showed no odor or irritation. Customer complaints about diaper rash dropped from 30 to 2 cases per month. The product passed EU CE certification (EN 14683-2019), and export share to Europe rose from 15% to 30%.
• Improved Quality: Waistband markings withstood 600 rubs without fading; PE backsheet graphics resisted urine contact with no smearing. Product return rate fell from 8% to 1.5%, and 96% of users praised the color clarity and durability (ΔE ≤ 0.6).
• Efficiency and Cost Optimization: Drying time shortened from 5s to 1.5s, line speed increased from 220 to 280 pcs/min, raising daily output by 1.44 million diapers. VOC treatment was no longer required, and ink utilization improved from 82% to 95%, saving RMB 450,000 annually.

Conclusion

As safety standards in baby care products become increasingly stringent, the StarColor SC8000 series water-based flexo inks offer a breakthrough solution — eliminating the health and environmental concerns of traditional solvent inks while delivering excellent adhesion and production efficiency. Whether for waistband logos or colorful backsheet patterns, StarColor ensures “non-irritating, rub-resistant, and eco-efficient” printing performance, protecting every baby’s delicate skin.

Today, StarColor partners with over 10 major diaper producers in China, with applications covering baby diapers, training pants, and wet wipe packaging. Choose StarColor SC8000 to enhance both safety and market competitiveness in baby care printing.