Analysis of Gravure Lamination Process
Date: Apr 27 2025 From: Star Color Views:
The gravure lamination process, with its high precision, high speed, and excellent printing quality, has become one of the core technologies in the production of product packaging for industries such as food, daily chemicals, and electronics.
With the continuous improvement of market requirements for packaging quality and the increasing strictness of environmental protection policies, the gravure lamination process is also continuously evolving and upgrading. This article will focus on analyzing the core aspects of the gravure lamination process, including equipment selection, material adaptation, and process flow.
I. Process Principle and Core Equipment Parameters
The gravure lamination process involves transferring ink or adhesive onto the surface of the base material through a gravure cylinder, and then laminating it with another layer of base material to form a multi-layer composite material with specific properties. The core of this process lies in the precise control of parameters in each link to ensure the quality of the laminated product and production efficiency.
| Component |
Technical Index |
Industry Benchmark Equipment Model |
| Gravure Cylinder |
Line count 200 - 400LPI, cell depth 25 - 50μm |
Shaanxi Beiren YTA - 2500 |
| Coating Unit |
Precision ±0.2g/㎡, speed 80 - 450m/min |
Sund SmartCoat 8.0 |
| Drying System |
Three-stage temperature zones (60℃/80℃/100℃) |
W&H Ecostar 3000 |
| Lamination Pressure Roller |
Linear pressure 20 - 50N/mm² |
Fuji Machinery (Japan) FX - 8C |
The line count and cell depth of the gravure cylinder directly affect the transfer amount of ink or adhesive and the clarity of the printed pattern. The Shaanxi Beiren YTA - 2500 gravure cylinder, through advanced engraving technology, can achieve precise control of the line count and cell depth to meet the printing requirements of different products.
The precision and speed of the coating unit determine the uniformity of the adhesive or ink on the base material and the coating efficiency. The Sund SmartCoat 8.0 coating unit, with its high-precision metering system and high-speed and stable coating performance, has become a preferred device in the industry.
The three-stage temperature zone design of the drying system can dry the coated base material in segments according to the volatility characteristics of different solvents. The W&H Ecostar 3000 drying system, through intelligent temperature control technology, ensures the drying effect while reducing energy consumption.
The pressure control of the lamination pressure roller affects the lamination strength of the two layers of base materials. The Fuji Machinery (Japan) FX - 8C lamination pressure roller can provide stable and adjustable linear pressure to ensure the lamination quality.
The gravure lamination equipment shows significant upgrading trends. The widespread application of the full-servo drive system has reduced energy consumption by 35% compared with traditional mechanical transmission. The servo drive system can precisely control the operation of each component of the equipment according to production needs, reducing energy waste. The introduction of the intelligent visual inspection module has achieved a registration accuracy of ±0.1mm, effectively improving the accuracy of the printed pattern and the qualification rate of products, and reducing material waste and production losses caused by registration errors.
II. Material Adaptation Matrix
Different product packaging has diverse performance requirements for composite materials, and the reasonable selection of substrate combinations is the key to achieving packaging functions. The following are five common substrate combination schemes, their applicable scenarios, and performance indicators:
| Structure |
Applicable Scenarios |
Peel Strength (N/15mm) |
Oxygen Permeability (cc/m²·day) |
| PET/AL/CPP |
High-temperature retort pouches |
≥8.5 |
<0.05 |
| OPP/VMPET/PE |
Puffed food packaging |
≥4.2 |
<2.0 |
| NY/EVOH/PE |
Vacuum packaging for meat |
≥6.0 |
<0.8 |
| BOPP/Paper/CPP |
Vertical packaging for daily chemical products |
≥3.5 |
<15 |
| PLA/PBAT/PLA |
Degradable environmental protection bags |
≥2.8 |
<25 |
The PET/AL/CPP combination is often used for high-temperature retort pouches. PET provides good mechanical strength and transparency, aluminum foil (AL) has excellent barrier properties, effectively blocking oxygen, water vapor, and light, and CPP has good heat-sealing performance and chemical resistance. The peel strength of this combination is ≥8.5N/15mm, and the oxygen permeability is <0.05cc/m²·day, which can meet the long-term preservation requirements of food under high-temperature retort conditions.
The OPP/VMPET/PE structure is suitable for puffed food packaging. OPP has high gloss and stiffness, VMPET (vacuum metallized polyester film) provides good barrier properties and aesthetic appearance, and PE serves as the heat-sealing layer, facilitating the sealing of the packaging. Its peel strength is ≥4.2N/15mm, and the oxygen permeability is <2.0cc/m²·day, which can prevent puffed food from getting damp and oxidizing.
For vacuum packaging of meat, the NY/EVOH/PE combination is an ideal choice. NY (nylon) has high strength and good puncture resistance, EVOH is a high-performance barrier material with strong resistance to oxygen and water vapor, and PE is used for heat sealing. The peel strength of this combination is ≥6.0N/15mm, and the oxygen permeability is <0.8cc/m²·day, which can effectively maintain the freshness and quality of the meat.
The BOPP/Paper/CPP combination is often used for vertical packaging of daily chemical products. BOPP provides gloss and strength, paper increases the texture and printability of the packaging, and CPP realizes the heat-sealing function. Its peel strength is ≥3.5N/15mm, and the oxygen permeability is <15cc/m²·day, meeting the packaging requirements of daily chemical products.
With the increasing awareness of environmental protection, the PLA/PBAT/PLA degradable environmental protection bags have gradually attracted attention. Both PLA (polylactic acid) and PBAT (polybutylene adipate terephthalate) are biodegradable materials. The peel strength of this combination is ≥2.8N/15mm, and the oxygen permeability is <25cc/m²·day, reducing environmental pollution while ensuring certain packaging performance.
The testing of material performance follows strict standards. GB/T 8808 - 1988 is used for peel strength testing. Through the specified testing methods and equipment, the bonding force between the layers of the composite material can be accurately measured. ASTM D3985 is used for oxygen permeability testing to help evaluate the barrier performance of the material and ensure that the packaging material meets the preservation requirements of the product.
III. Six Key Points of Precise Control in the Process Flow
3.1 Substrate Pretreatment
Substrate pretreatment is the primary link to ensure the quality of gravure lamination. Corona treatment can increase the surface energy of the substrate surface to ≥42dyn/cm (tested with a dyne pen), enhancing the adhesion of the substrate to the ink or adhesive.
It is crucial to control the environmental humidity at 45±5% RH. Excessive or insufficient humidity may cause the film roll to deform, affecting the subsequent lamination process.
3.2 Adhesive Coating
The quality of adhesive coating is directly related to the lamination effect of the two layers of substrates. For solvent-based adhesives, the dry coating amount is usually controlled at 2.5 - 3.5g/㎡ to ensure sufficient adhesion, while avoiding problems such as increased costs and insufficient drying caused by excessive use of adhesive.
When using two-component polyurethane adhesives, it is necessary to mix them strictly according to the ratio of main agent: curing agent = 10:1 to ensure that the adhesive is fully cured and a firm bonding layer is formed. Precise ratio and uniform mixing are the keys to ensuring the performance of the adhesive. Any ratio error may lead to a decrease in lamination strength or incomplete curing, affecting the quality and service life of the product.
3.3 Precise Drying
The control of the drying process is an important link to ensure the quality and safety of the laminated product. According to the GB/T 10004 - 2008 standard, the solvent residue is required to be ≤5mg/㎡. Through the three-stage temperature zone drying system, the wind speed gradient (adjusted in three stages of 10/15/20m/s) is reasonably set to make the solvent volatilize gradually.
The temperature of the first-stage temperature zone is relatively low, mainly used for pre-drying to make the solvent volatilize slowly and avoid the surface of the adhesive from crusting due to excessive temperature, which affects the volatilization of the internal solvent. The temperature of the second-stage temperature zone is increased to accelerate the volatilization speed of the solvent. The third-stage temperature zone further removes the residual solvent to ensure thorough drying.
3.4 Hot Press Lamination
In the hot press lamination stage, the temperature of the steel roller is usually set at 60 - 90℃, the temperature of the pressure roller is controlled at 35 - 50℃, and the lamination line pressure is maintained at 30 - 45N/mm. An appropriate temperature can make the adhesive in a good molten state, enhancing its fluidity and wettability, and ensuring that the two layers of substrates can be fully bonded. A stable pressure ensures the close fit between the substrates, forming a uniform laminated layer.
Excessive temperature may cause the adhesive to decompose or the substrate to deform, while too low a temperature will prevent the adhesive from fully exerting its bonding effect. Excessive pressure may damage the substrate, and insufficient pressure will result in insufficient lamination strength.
3.5 Curing Control
The curing process is a necessary step to fully cure the adhesive and improve the lamination strength and stability. The curing time is generally 48 - 72 hours, the temperature is maintained at 40 - 50℃, and at the same time, the environmental cleanliness is ensured to reach Class 100,000.
During the curing process, the molecules in the adhesive further crosslink to form strong chemical bonds, making the performance of the laminated layer more stable. A clean environment can prevent dust, impurities, etc. from contaminating the laminated product and avoid quality problems caused by the mixing of foreign substances.
3.6 Slitting and Inspection
Slitting and inspection is the last process of the gravure lamination process and is directly related to the finished product quality. An online defect inspection system is adopted, which can detect the defects on the surface of the laminated film in real-time. It can detect defects as small as 0.1mm², and unqualified products can be promptly found and removed to prevent unqualified products from entering the market.
The slitting burrs are monitored by a laser diameter gauge, and the slitting burrs are required to be ≤20μm to ensure the flatness and smoothness of the slitting edge and improve the appearance quality and usability of the product. The precise control and strict inspection in the slitting process are important guarantees for ensuring the consistency of product quality and customer satisfaction.
The gravure lamination process involves several key links such as equipment selection, material adaptation, and process flow. The precise control and technological upgrading of each link have an important impact on product quality and production efficiency.
With the continuous progress of technology and the increasing strictness of environmental protection requirements, the gravure lamination process is continuously developing in the direction of high efficiency, energy conservation, and environmental protection.
RU
EN
CN
