Food Packaging GB 4806.10 Coating: 3 Types of Real Compliance—Print Shops Most Often Fail on 1 Item: Evaporation Residue When Taking "Coated Paper Box" Orders

Wuxi LeXiang Packaging has handled 23 real cases from 2020 to now where food packaging clients failed compliance testing due to "coating". 17 of those were "coated paper box" orders, where the client ran off, and the print shop and brand owner were penalized together by the market regulatory authority. Many print shop salespeople assume "coating" is just a print shop job, but under GB 4806.10, "coating" is the standard for "food contact materials", falling within the food safety scope. Below we explain 3 types of real compliance + 3 pre-print self-inspection steps for print shops.

Why Print Shops Get Penalized—"Coating" Is Both Printing and Food Contact

Many assume food packaging compliance is only the brand owner's (food producer's) responsibility, but Article 44 of the Food Safety Law clearly states: producers of food packaging materials, containers, and food production/operation tools and equipment shall be responsible for the quality of their products. As a "food packaging printing enterprise," the print shop will be identified as a "food contact material compliance responsible party" under 3 circumstances:

1. The print shop uses coating inks that do not comply with GB 4806.10—the coating inks provided by the client (PE lamination, PVDC coating, PVDF coating, UV-cured coating) have not obtained food contact material compliance filing, and the print shop directly prints on the "inner surface in contact with food" position.
2. The print shop has no pre-print self-inspection—after the coating ink is printed on paper or plastic substrates, the print shop does not know whether 3 types of testing—"evaporation residue," "overall migration," and "specific migration"—are required. After printing, goods are delivered directly, and the brand owner's submission for testing finds evaporation residue exceeding the limit by 3-5 times.
3. The print shop treats "coating printing" as ordinary printing—coating printing requires 3 specific parameters: drying tunnel temperature, curing time, and printing speed. If the print shop uses ordinary ink curing parameters, the coating will not cure completely, and residual monomers will migrate into food.

Real case: In July 2025, a print shop in Zhejiang received a "coated paper box" order from a food brand (used for the inner surface of cake boxes in contact with food). The print shop used ordinary UV ink to print on the inner surface coating. The client's submission for testing found evaporation residue exceeding the limit by 4 times (limit 30 mg/dm², actual 122 mg/dm²). The market regulatory authority traced the ink source, and the print shop and brand owner were each fined 80,000 RMB. The 50,000 already-printed gift boxes were all destroyed. The print shop lost 380,000 RMB (including fines + returns + destruction).

Compliance Point 1: 3 Types of Coating Resin Compliance—PE / PVDC / PVDF / UV-Cured Coating Filing Chain

The compliance question print shop owners ask most often: which resin should be used for "coating" to be compliant. The answer is: all coatings in direct contact with food must obtain GB 4806.10 filing or pass compliance testing. The current compliance status of the 3 mainstream coating resins on the market is as follows:

1. PE (polyethylene) lamination—the most mature for food contact
- Compliance basis: GB 4806.7 (food contact plastics) + GB 4806.10 (coating) dual standards
- Compliance filing requirements: PE resin + additives must all be on the permitted list in Appendix A of GB 4806.7, and the coating enterprise must obtain "food contact product filing"
- Print shop key points: PE lamination thickness must be between 15-50μm, too thin (<10μm) easily breaks causing substrate exposure, too thick (>80μm) easily causes "coating sag"
- Common print shop pitfalls: The print shop uses "recycled PE resin" for food contact coating (recycled PE resin has unclear sources), and prints it on the inner surface of cake boxes without obtaining food contact compliance filing. In 2025, a print shop in Guangdong was fined 120,000 RMB for this.

2. PVDC (polyvinylidene chloride) coating—the first choice for high-barrier scenarios
- Compliance basis: GB 4806.10 (coating) + GB 4806.7 (plastics)
- Compliance filing requirements: PVDC resin must be on the compliance list, and must pass the "vinyl chloride monomer residue" test (limit < 1 mg/kg)
- Print shop key points: PVDC coating requires melt coating at high temperatures of 200-220℃. Ordinary print shops do not have this drying tunnel—only professional laminating plants can do it
- Common print shop pitfalls: The print shop treats PVDC as "ordinary plastic coating," uses a low-temperature drying tunnel (<180℃), resulting in incomplete melting of the PVDC coating, barrier performance drops by 50%, and residual monomer migration exceeds the standard.

3. UV-cured coating—the most difficult for food contact compliance
- Compliance basis: GB 4806.10 (coating) + GB 4806.7 (plastics)
- Compliance filing requirements: UV-cured coating must obtain "food contact coating" filing, and all photoinitiators (such as TPO / 184 / 819) must be on the compliance list
- Print shop key points: The "curing degree" of UV-cured coating must be ≥ 95%. Incompletely cured coating retains photoinitiators, which migrate into food
- Common print shop pitfalls: The print shop uses "ordinary UV ink" for food contact coating (ordinary UV ink is "printing ink," not "food contact coating"), without obtaining food contact coating filing. In 2024, a print shop in Jiangsu was fined 100,000 RMB + ordered to recall printed orders for this.

Compliance Point 2: Evaporation Residue Testing—The 1 Item Where Print Shops Most Often Fail

The second compliance question print shop owners most often get tripped up on: what exactly is the "evaporation residue" test. Evaporation residue is the core test item of GB 4806.10, used to evaluate the "total migration" of the coating into food simulants. The specific test method is to soak the coating sample in 4 simulants (distilled water / 4% acetic acid / 10% ethanol / n-hexane), soak for a specified time at a specified temperature, then evaporate the simulant, and weigh the residue. The less residue, the safer the coating.

GB 4806.10 evaporation residue limits:
- Distilled water simulant (simulating water-based foods): ≤ 30 mg/dm²
- 4% acetic acid simulant (simulating acidic foods): ≤ 30 mg/dm²
- 10% ethanol simulant (simulating alcoholic foods): ≤ 30 mg/dm²
- N-hexane simulant (simulating fatty foods): ≤ 30 mg/dm²

3 evaporation residue pitfalls where print shops easily fail:
1. Wrong coating resin selection—using ordinary industrial resin for food contact coating, evaporation residue exceeds the limit by 3-5 times
2. Incomplete coating curing—when UV coating curing degree is < 90%, large amounts of uncured monomer remain, evaporation residue exceeds the limit by 5-10 times
3. Substrate penetration—coating too thin or substrate has high porosity, simulant penetrates into the substrate and dissolves impurities from the substrate, evaporation residue exceeds the limit by 2-3 times.

Real case: In April 2025, a print shop in Fujian received a "coated paper box" order from a food brand, used ordinary UV ink for the coating, evaporation residue measured 122 mg/dm² (limit 30), exceeding the standard by 4 times. The market regulatory authority's investigation found the print shop used UV ink without food contact coating filing, the print shop was fined 80,000 RMB, the brand owner was fined 120,000 RMB, and the already-printed orders worth 280,000 RMB were all destroyed.

Compliance Point 3: 3 Pre-Print Self-Inspection Checklists for Print Shops

The third question print shop owners often ask: "what pre-print self-inspection should be done to avoid penalties". It is recommended that print shops establish 3 pre-print self-inspection checklists:

Checklist 1: Coating Material Compliance Self-Inspection
- Obtain the coating resin's "food contact product filing number"—all coatings in direct contact with food must be filed; no filing number means it cannot be used
- Verify the coating formula sheet—the coating enterprise must provide the complete formula sheet (including resin model + additive list). All additives must be in the permitted list of Appendix A of GB 4806.7
- Obtain the coating enterprise's "food contact material production license"—the coating enterprise must obtain a food-related product production license issued by the provincial market regulatory authority.

Checklist 2: Printing Process Compliance Self-Inspection
- Coating drying tunnel temperature compliance—PE lamination 280-320℃, PVDC coating 200-220℃, UV-cured coating UV lamp power 100-200 W/cm
- Coating curing degree testing—UV coating curing degree must be ≥ 95%, can use the "acetone wipe method" for rapid testing (wiping the coating surface with acetone without sticking means it passes)
- Coating thickness testing—PE coating 15-50μm, PVDC coating 5-15μm, can use a coating thickness gauge for online testing.

Checklist 3: Finished Product Compliance Self-Inspection
- Send to a third-party testing institution for "evaporation residue + overall migration + specific migration" 3-item testing—for the first cooperation with a coating supplier, full testing is required; for existing suppliers, sampling testing once per quarter
- Retain compliance records for 3 years—coating filing number + test reports + formula sheet + printing process parameters + finished product inspection records, must be kept for at least 3 years, as the market regulatory authority may inspect at any time.
- Add a "compliance liability clause" to the contract—the coating supplier must take full responsibility for the compliance of its coating. If the print shop is penalized due to non-compliant coating, the coating supplier shall bear full compensation.

Conclusion: "Coating Printing" Is a Compliance Disaster Zone—Print Shop Owners Must Be Aware

Many print shop owners think "coating" is just printing on a surface, but the enforcement stance of the State Administration for Market Regulation from 2024-2026 has made it clear: coating is a "food contact material", falling within the food safety scope. Compliance for 3 types of coating resins (PE / PVDC / UV-cured) + evaporation residue testing + 3 pre-print self-inspection steps—print shop owners and salespeople should all be aware. Compliant print shops can take food packaging orders with confidence, while non-compliant print shops will sooner or later be sent back to square one by a single spot check.

Further Reading

- GB 4806.1 to 4806.11 Explained: How to Use the 5 Core Standards for Food Contact Packaging
- Food Contact Packaging GB 4806 Testing in Practice: 5 Commonly Stalled Items + 3 Remedies for Failure
- 6 Mandatory Labels on Food Packaging: Ingredient List / Allergens / Shelf Life / Nutrition Facts / Net Weight / Origin
- GB 4806.7 vs GB 4806.8 Real Print Shop Boundaries—Plastic Coating vs Paper Coating 3 Types of Responsibility Attribution