What is the main difference between reverse printing and traditional gravure surface printing?

Reverse printing forms a structure of 'substrate → ink → aluminum plating → lamination layer', sandwiching the ink layer between the substrate and aluminum plating/lamination layer. This contrasts with traditional gravure surface printing, where the ink layer is directly exposed. Key advantages of reverse printing include a ≥40% increase in reflectivity due to the aluminum plating layer, 3x higher abrasion resistance as the ink is protected, and optimized safety by blocking direct contact between ink and contents.

What are the key performance indicators that make reverse printing ink stand out from traditional gravure ink?

Reverse printing ink has stricter performance requirements: ≥4.5N/15mm adhesion on PET film (vs. ≥3.0N for traditional), ≤5mg/m² toluene residue (vs. ≤15mg/m²), ≥2.5N/15mm lamination strength (not required for traditional), and resistance to delamination at 121℃ for 30 minutes (vs. 80℃/10min for traditional). These ensure superior durability, safety, and process adaptability.

What are Gravure Reverse Inks?

Date: Apr 22 2025 From: Star Color Views:

In the packaging and printing industry, which continually pursues higher quality and safety, gravure reverse printing ink stands out for its unique performance advantages. This article provides a comprehensive and in-depth analysis of gravure reverse printing ink from the perspectives of its scientific definition, technical core, application scenarios, and compliance requirements.

I. Scientific Definition of Gravure Reverse Printing Ink

1.1 Principle of Reverse Printing Process

Unlike traditional gravure surface printing, where the ink layer is directly exposed on the print surface, reverse printing innovatively sandwiches the ink layer between the substrate and the aluminum plating/lamination layer, forming a structure of "substrate → ink → aluminum plating → lamination layer." This structural design offers significant advantages:

High Glossiness: The aluminum plating layer covering the ink acts as a smooth reflector, increasing reflectivity by ≥40%. This gives printed products a brilliant, eye-catching luster.
Enhanced Durability: The ink layer is protected by the aluminum plating and lamination layers, reducing direct exposure to external factors. Its abrasion resistance is three times higher than that of traditional processes, ensuring the integrity and longevity of printed patterns.
Optimized Safety: This structure effectively separates the ink from the packaged contents, preventing harmful substance migration and providing reliable safety for food and pharmaceutical packaging.

1.2 Key Performance Indicators of Reverse Printing Ink

Reverse printing ink has stricter requirements for several key performance indicators compared to traditional gravure ink, as shown in the table below:

Parameter	Reverse Printing Ink Requirement	Traditional Gravure Ink	Test Standard
Adhesion (PET Film)	≥4.5N/15mm	≥3.0N/15mm	ASTM D3359
Solvent Residue	≤5mg/m² (toluene residue)	≤15mg/m²	GB/T 10004
Lamination Strength	≥2.5N/15mm	Not required	ISO 11339
Cooking Resistance	No delamination at 121℃/30min	80℃/10min	JIS Z 0238

These strict indicators ensure the stability and reliability of reverse printing ink in complex application scenarios.

Gravure printing ink

II. Technical Core and Innovations of Reverse Printing Ink

2.1 Resin System Design

The high performance of reverse printing ink relies on a carefully designed resin system, including base resins and functional additives:

Base Resin Selection:
- Polyurethane-Modified Chlorinated Polypropylene (CPP): Modification treatment significantly enhances the bonding force with the aluminum plating layer, ensuring a tight connection between the ink and aluminum plating for structural stability.
- Nitrocellulose: Its unique chemical structure provides excellent solvent release properties, reducing toluene release by 28% and minimizing organic solvent residues to meet environmental and safety standards.
Functional Additives:
- Nano-Silica (Particle Size 30-50nm): Uniformly dispersed nano-silica forms a hard, abrasion-resistant protective layer on the ink surface, greatly improving wear resistance.
- Coupling Agent (KH-550): Acting as a "bridge" between the ink and aluminum plating layer, the coupling agent improves interfacial bonding and compatibility, ensuring high-quality printing.

2.2 Solvent Formula Optimization

Solvents play a critical role in dissolving resins and regulating drying speed. Reverse printing ink uses a unique ternary azeotropic system through precise solvent ratio adjustment:

Solvent Type	Volume Percentage	Boiling Point (℃)	Role
Ethyl Acetate	45-55%	77.1	True solvent, dissolves resins to ensure ink fluidity and uniformity
Isopropyl Alcohol	15-20%	82.3	Viscosity reducer, adjusts drying speed for easier ink transfer
Propylene Glycol Methyl Ether	10-15%	120.2	Slow-drying agent, prevents premature drying and plate blocking

This innovative solvent formula reduces drying time to 70% of traditional formulations, significantly improving production efficiency and reducing energy consumption.

III. Typical Application Scenarios and Performance Data

3.1 High-Temperature Cooking Packaging

In pet food bag applications, reverse printing ink demonstrates excellent resistance to high and low temperatures. After testing at 121℃ for 40 minutes followed by freezing at -18℃, the ink layer shows no cracking, and lamination strength remains at 2.8N/15mm, ensuring packaging integrity during high-temperature sterilization and low-temperature storage.

3.2 High-Barrier Pharmaceutical Packaging

For blister composite film printing, reverse printing ink excels in oxygen barrier and radiation resistance. Its oxygen permeability is ≤0.5cm³/m²·day (ASTM D3985), effectively preventing drug oxidation. Under a 50kGy γ-ray irradiation dose, color change ΔE≤1.5, ensuring clear patterns and stable colors during irradiation sterilization.

3.3 Daily Chemical Flexible Packaging

Take shampoo stand-up pouches as an example: reverse printing ink shows excellent chemical and compressive resistance. After immersion in 5% NaOH solution for 48 hours, the ink does not peel off. It can also withstand a load of ≥15kg without delamination (GB/T 4857.3), meeting the storage and transportation needs of daily chemical packaging.

zhongzhixing Gravure printing ink

IV. Global Compliance Requirements and Certification Paths

4.1 Major Market Access Standards

Different regions have strict safety and environmental standards for packaging inks, as outlined in the table below:

Region	Food Safety Standard	Environmental Requirement	Key Test Items
European Union	EU 10/2011	VOC≤30g/kg (Directive 2004/42/EC)	Specific migration (e.g., primary aromatic amines)
United States	FDA 21 CFR 175.300	TSCA Title VI	Solvent residue (toluene≤5ppm)
China	GB 9685	HJ 371-2018	Total heavy metals (Pb+Cd+Hg≤5mg/kg)

Enterprises must strictly adhere to these standards to ensure product compliance when entering different markets.

Recommendation for Zhongzhixing Gravure Reverse Printing Ink

Zhongzhixing Gravure Reverse Printing Ink, a water-based ink, stands out in the market for its outstanding performance:

High Adhesion: Specifically designed for reverse internal printing on common substrates like PET film, it ensures firm pattern adhesion and strong lamination fastness, passing strict FDA testing to meet food-grade safety requirements.
Environmental Friendliness: Compliant with international VOC emission standards, it minimizes environmental pollution during production and use.
High Efficiency: With a printing speed of 80-200 meters per minute, it meets the needs of high-speed industrial production, helping enterprises improve efficiency and reduce costs.

Zhongzhixing’s product embodies the technical advancements of reverse printing ink, providing a reliable solution for high-quality, safe, and efficient packaging applications.