Grey cardboard (also known as grey cardboard or industrial cardboard) is a high-density, high-strength cardboard material widely used in high-end packaging (such as gift boxes, hardcover book covers), furniture lining, advertising displays, and other fields.

Technical characteristics of Greyboard production line

1. Raw material processing and pulping technology

Raw material selection: Using 100% recycled waste paper (OCC), wood pulp, or mixed pulp, efficiently de ink and remove impurities through a high concentration pulper (12-15% concentration).

Fiber optimization: multi-stage refining machine (conical/disc grinding) treatment, controlling fiber length (0.8-1.2mm), balancing strength and surface smoothness.

Environmental additives: Adding wet strength agents (PAE) and sizing agents (AKD) to enhance water resistance and reduce formaldehyde emissions.

2. Forming and dehydration process

Multi layer composite copying: Multiple circular mesh forming machines (4-8 layers) are used, and the quantity of each layer can be independently adjusted (such as using fine fibers for the surface layer and coarse fibers for the bottom layer).

High pressure dehydration: Combined pressing (shoe pressing+vacuum suction tank), the dryness is increased to 45-50%, reducing drying energy consumption.

Surface treatment: Online coating technology (such as scraper coating) improves smoothness and meets subsequent printing requirements.

3. Drying and calendering technology

Energy saving drying: Multiple sets of steam dryers (1.2-1.5MPa) combined with hot air hoods can increase thermal efficiency by 30%.

High precision calendering: The soft calender (temperature 120-180 ℃) controls the thickness tolerance (± 0.02mm), and the glossiness can reach 60-80GU.

4. Intelligent control system for industrial cardboard production line

DCS/PLC integration: Real time monitoring of quantitative, moisture (accuracy ± 0.5%), thickness, automatic adjustment of slurry flow rate and drying temperature.

Predictive maintenance: Vibration sensor+AI algorithm alerts for abnormal roller bearings, reducing unplanned downtime.

Core advantages

1. High strength and durability: The fiber structure is compact, with excellent compression and bending resistance. The ring compression strength (RCT) can reach over 400N/m, far exceeding ordinary cardboard. Strong stability under humidity changes, not easily warped (≤ 3mm/m ²), suitable for precision packaging (such as electronic products). Crafted through 4-8 layers of circular mesh, the surface layer is delicate and the bottom layer is rough, balancing surface smoothness and overall strength.

2. Excellent printability and processability: The surface is suitable for high-definition printing (UV, hot stamping, embossing, etc.), enhancing the packaging grade. The sizing process (AKD/rosin size) controls the ink absorption rate to avoid smudging. Moderate hardness, easy to process into complex structures such as gift boxes and book cases in the later stage.

3. Environmental Protection and Sustainability: The main raw material is waste paper pulp (OCC), reducing dependence on native wood. Wastewater closed-loop treatment (COD<50mg/L); Formaldehyde free adhesives (such as PAE wet strength agents) meet food contact standards. Replace plastic foam and metal lining plate to reduce white pollution.

4. Efficient production and energy conservation: with a width of 2.8-5.6m, a vehicle speed of 300-600m/min, and a daily production capacity of 100-300 tons per line. Steam consumption per ton of paper ≤ 1.8 tons (waste heat recovery system); Electricity consumption ≤ 500kWh (intelligent frequency conversion control). The automated cutting scrap rate is less than 1.5%, and the raw material utilization rate exceeds 98%.

The grey paper hardboard production line achieves a balance between high performance and sustainability through high-strength structural design, intelligent control, and green manufacturing processes. Its advantage lies in meeting the aesthetic and protective needs of high-end packaging, while also conforming to the global trend of plastic reduction and low-carbon environmental protection. It is the preferred upgrade for traditional packaging materials.

If you are also interested in this machine,please don’t hesitate to contact us:

Overseas manager: Tom Wang

Email:cartonmachine.tomwang@aliyun.com

Phone/Wechat/Whatsapp:+86 13303078975