Egg trays are a prime example of environmentally friendly packaging. Their production fundamentally relies on pulp preparation. The quality of the pulp directly determines the final egg tray's strength, shape, and appearance. As a professional manufacturer of egg tray machinery, AGICO provides an in-depth analysis of the raw materials, equipment, process, and key points of pulp preparation.
1. Selection and Preparation of Pulp Raw Materials
The core raw material for pulp preparation is various types of recycled fiber. This primarily includes:
Waste Paper: Common sources are office paper, books, and magazines. This type offers medium fiber length and is a high-quality raw material.
Waste Cardboard: Examples include old cartons and card stock. This provides coarser fibers, which contribute to better stiffness.
Other Recyclable Fiber Materials: Some agricultural waste, like bagasse, can be blended in specific proportions but requires pre-treatment.
Key Points on Raw Materials:
Materials require initial sorting to remove impurities like plastic, metal, and adhesive tape.
While ink, hot melt glue, etc., can be partially dispersed during pulping, excessive amounts will affect pulp cleanliness.
The raw material mix ratio needs adjustment based on the strength requirements of the target product (e.g., egg trays, fruit trays, industrial packaging). AGICO recommends clients establish stable raw material supply channels to ensure batch-to-batch consistency.
2. Key Equipment: Configuration of the Pulping System
The core equipment for pulp preparation is the Hydraulic Pulper. Its function is not only to break down waste paper but also to separate and individualize fibers through the combined action of mechanical and hydraulic forces. This creates a uniform pulp slurry.
Features of AGICO Pulpers:
They utilize a high-power rotor and bedplate design. This ensures high disintegration efficiency with reasonable energy consumption control.
The tank structure promotes fiber circulation and prevents settling.
Systems can be configured as batch or continuous types based on production capacity. They can also be paired with cleaning equipment like debris removers and screens.
Equipment selection must match daily output needs. Bigger is not always better. AGICO engineers recommend appropriate pulper volume and power configuration. These recommendations are based on the client's actual raw material situation and product plans.
3. Detailed Pulp Preparation Process Flow
Pulp preparation is more than just "shredding waste paper." It is a controlled multi-stage process.
Soaking and Pre-Softening
Sorted raw materials are fed into the pulper along with process water for thorough soaking. This step softens fibers and dissolves some water-soluble substances. It significantly reduces the energy consumption of the subsequent disintegration stage. Soaking time needs adjustment based on the type of raw material and water temperature.
Disintegration and Defibering
The pulper is started to disintegrate the raw materials into a fiber suspension. The goals of this stage are:
To completely separate fibers and avoid "paper bundles."
To preserve fiber length as much as possible. Excessive cutting reduces final product strength.
To detach ink and contaminants from the fibers.
Consistency Adjustment and Refining
The pulp after disintegration has a high consistency. It needs to be diluted with water to the consistency required for the forming process (typically 0.8% - 1.5%). Simultaneously, refining equipment (like a refiner) can be used to gently fibrillate the fibers. This increases the fiber surface area, improving the binding strength and surface smoothness of the final product.
Pulp Cleaning and Storage
The diluted pulp slurry must pass through cleaning stages like sand removal and screening. This removes fine grit and undissolved impurities. The cleaned pulp is stored in a holding tank. Continuous agitation keeps the fibers uniformly suspended. This ensures a stable supply to the forming machine.
Core Process Control Points:
Consistency Stability: Fluctuations in consistency directly affect the uniformity of fiber pickup at the forming stage. This leads to inconsistent product weight.
Fiber Uniformity: The slurry must not contain fiber bundles or undispersed material.
PH and Water Quality: A neutral or slightly alkaline environment aids fiber dispersion. Water hardness should not be too high.
The prepared pulp is pumped through pipelines to the AGICO Egg Tray Forming Machine. Under vacuum suction, fibers from the slurry deposit onto the mold surface and dewater. This forms a wet blank. Subsequent hot-press drying and other steps turn it into the finished product.
How Pulp Properties Affect Forming
Fiber Type and Blend
Determines the tray's toughness (drop resistance) and rigidity (stacking strength).
Freeness (Drainage Rate)
Affects water drainage speed and product density. Higher freeness gives a smoother surface but slower drainage. Lower freeness drains faster but yields a rougher surface.
Additives
Wet-strength agents (improve wet strength for easier demolding), water-resistant agents (for moisture-resistant products), or dyes can be added as needed.
AGICO forming machines are designed for excellent compatibility with pulp slurries. Through precise control of the vacuum system and mold heating temperature, they can produce structurally sound and well-formed products. These include egg trays, fruit trays, and industrial pads. This is achievable even when using 100% recycled fiber pulp.
5. AGICO Services and Support
Pulp preparation is the first step in egg tray production. It is also the foundation determining cost and quality. AGICO provides complete production line equipment. This covers pulping, forming, drying, and packing. More importantly, we focus on providing process support:
Assisting in designing rational raw material blend formulas.
Training operators to master key parameter testing and adjustment. These parameters include pulp consistency and freeness.
Sharing industry expertise to help clients optimize pulp formulas for different order requirements.
Choosing AGICO means investing in a proven, efficient egg tray production solution. We are committed to making the manufacturing of eco-friendly packaging more stable and more economical.
AGICO Egg Tray Machine Provider
For more information on how the AGICO egg tray production line can be adapted to your specific pulp process, or to obtain a customized equipment proposal, please feel free to contact us.