StarColor SCVS Food-Grade Water-Based Varnish | Safe & Premium Cake Plate Finish
Date：2025-10-13 14:54:51 from：StarColor Ink
Cake paper plates, which come into direct contact with cream, chocolate, and hot cakes, require not only visually appealing glossy printing but also strict safety standards — migration-free, oil-resistant, and heat-tolerant. StarColor has developed the SCVS series food-grade water-based varnish, offering zero solvent residue, high oil and heat resistance, and low VOC emissions. This solution has been adopted by leading paper product manufacturers in China, providing both safety and premium appearance for cake paper plates.
Industry Challenges
The usage scenarios of cake paper plates (direct contact with high-fat, high-sugar foods and supporting cakes at 60–80°C) combined with the food safety standard GB 4806.8-2016 (National Food Safety Standard for Paper and Paperboard Materials in Contact with Food) create difficulties for traditional varnishes:
- Safety Risks: Solvent-based varnishes contain benzene and ketone solvents, with residuals often exceeding 5 mg/m². When the plates contact cream or cake, residual solvents may migrate into food, causing odor contamination or gastrointestinal irritation, violating GB 4806.8-2016 limits (no odor, specific migration ≤0.01 mg/kg).
- Poor Oil and Heat Resistance: Cream and chocolate contain high levels of oil; traditional water-based varnishes provide poor oil resistance, leading to pattern smearing. When supporting cakes above 60°C, the varnish layer may soften, wrinkle, or delaminate from the paper base, reducing protection and decorative effect.
- Gloss vs. Flexibility Trade-Off: Some manufacturers opt for low-gloss water-based varnish for safety, resulting in dull prints. Applying multiple layers to increase gloss can make plates stiff and brittle, causing cracks during folding and affecting hand feel.
StarColor Solution
StarColor optimized both varnish formulation and coating process to meet cake paper plate requirements, launching the SCVS series food-grade water-based varnish to precisely address these industry pain points:
1. Safer Varnish Formulation
- Zero-Residue Safety: Made with food-grade polyurethane-modified acrylic resin (compliant with FDA 21 CFR 175.300), using deionized water as the main solvent (80%). VOC content ≤20 g/L; residual solvent after drying <1 mg/m². Odor migration tests show no detectable odor; specific migration ≤0.005 mg/kg, fully meeting food contact requirements.
- High Oil & Heat Resistance: 3% nano-silica additive forms a dense crosslinked film on the plate surface. Oil resistance reaches Level 5 (GB/T 15171-2016). Cream and chocolate remain non-bleeding after 8 hours. Epoxy-modified monomers (10%) provide thermal tolerance from -5°C to 120°C; plates can support 80°C hot cakes for 30 minutes without softening or wrinkling.
- Gloss and Flexibility Balance: Resin blending and additive adjustments achieve 60° gloss of 75–85 GU (high gloss) or 40–50 GU (matte). Glass transition temperature (Tg) controlled at 35–40°C; plates can bend 180° without cracking, maintaining flexibility for manual folding.
2. Process Adaptation: Compatible with Existing Equipment
- Coating Parameters: Compatible with high-line-count anilox rollers. Coating weight controlled at 4–6 g/m² (dry) to avoid plate stiffening. Squeegee hardness: 70 Shore A; pressure: 1.2–1.5 bar to ensure even coating without missed spots.
- Drying Optimization: Two-stage drying: Stage 1 — 40°C for 1 second (surface set, avoid sticking); Stage 2 — 60°C for 2 seconds (full crosslinking). Total drying time: 3 seconds, compatible with 200–300 pcs/min high-speed production without wet-film adhesion.
- Ink Compatibility: Fully compatible with mainstream food-grade water-based inks (e.g., StarColor ZX-SW series). Post-coating adhesion exceeds 500 rub cycles (500g load), ensuring durability during transport and storage.
Case Study: Cake Paper Plate Upgrade at a Leading Paper Manufacturer
Zhejiang Paper Co., a major Chinese baking packaging supplier producing over 500 million cake plates annually for chain bakeries, faced rising complaints of “cake odor” from solvent-based varnish and European export blocks due to over-limit migration. After introducing StarColor SCVS food-grade water-based varnish in March 2024, the company achieved a full product upgrade.
Project Background: From Compliance Crisis to Quality Breakthrough
Previously, solvent-based varnished plates generated over 25 odor complaints per month. EU-bound plates were blocked due to specific migration exceeding 0.012 mg/kg, causing direct losses exceeding RMB 800,000. VOC emissions also exceeded limits, requiring corrective measures within 3 months.
Results: Safety, Quality, and Market Success
- Safety Compliance: Residual solvents undetectable; migration tests fully comply with GB 4806.8-2016 and EU 10/2011 standards. Blocked export goods were released; EU export share increased from 20% to 40%.
- Quality Enhancement: Cream 8h / 80°C hot cake 30min: no oil bleed, no deformation; printed patterns remain sharp. Gloss reached 80 GU, improving visual appeal. Repeat orders increased from 85% to 98%.
- Cost & Efficiency Optimization: Coating weight reduced from 8 g/m² (solvent varnish) to 5 g/m², saving 37.5% in raw material costs. No VOC treatment required; annual environmental cost saving: RMB 280,000. Drying time shortened by 40%, line speed increased from 220 to 280 pcs/min, daily output increased by 480,000 plates, meeting peak season demand.
Conclusion: Preferred Safe Varnish for Food-Contact Packaging
StarColor SCVS food-grade water-based varnish addresses safety and performance limitations of traditional varnishes while optimizing production efficiency. It provides cake plates with three advantages: safety, visual appeal, and flexibility. The product now covers cake plates, pizza boxes, sandwich wrappers, and other food-contact applications, serving over 30 paper product manufacturers. Choosing StarColor ensures compliance with global safety standards and strengthens market competitiveness, safeguarding consumers’ food-contact experience.
