In modern packaging, pulp molded products, due to their environmentally friendly, biodegradable, and flexible design, are increasingly becoming an ideal choice for a variety of applications, including food trays, egg trays, and industrial liners. Producing high-quality paper trays requires not only the pulp raw material but also the appropriate use of various additives and precise control of the production process.
Additive Selection and Ratio Control
In actual production, pulp molded products often require the addition of chemical additives to enhance their physical properties and applicability. Sizing agents are a common type of additive, primarily used to enhance the product's liquid resistance, such as water and oil repellency. Common sizing agents include rosin sizing, paraffin emulsions, and their combination. When using recycled waste pulp as raw material, a generally recommended addition level of 1.5% to 2% is effective in improving interfiber bonding and enhancing the strength of the finished product.
The use of fillers is also crucial. Talc, with its fine particles and easy retention and application, is the most commonly used filler for increasing yield and surface smoothness. Typically, talc powder is prepared by suspending 20%-30% talc in water, stirring for approximately 6 minutes, and then diluting with water. Other additives are added, stirred for an additional 5 minutes, and finally mixed with the main pulp. Furthermore, functional additives such as oil repellents, wet strength agents, or retention aids can be added to the pulp to expand its application range, depending on the intended use.
Pulp concentration is another crucial factor in determining fiber dispersion and molding. White or clean water is typically added during the pulping process to precisely adjust the feed concentration to 1%-2%, as this concentration must be maintained stable during the subsequent molding process.
The Importance of Production Process and Mixing Technology
The quality of molded pulp products depends largely on the control of the pulping and mixing processes. For example, in the production of egg trays, the mixing process directly affects the fiber bonding and physical properties of the final molded pulp product.
AGICO has extensive expertise in the design and production of pulp mixing systems. Our mixing equipment can adjust the mixing intensity and ratio to meet customers' specific requirements for product weight, waterproofing, color, and even anti-slip properties, enabling diversified production.
After the equipment is installed and commissioned, the technical team will provide on-site guidance to operators on key papermaking preparation techniques, ensuring stable production within a short period of time.
Analysis of Product Thickness and Hot Press Dehydration Mechanisms
Hot pressing of pulp molded products is a dynamic process involving coupled mechanical compression, fluid migration, and heat and mass transfer. Therefore, dehydration is primarily achieved through direct extrusion and percolation within the porous medium, with some water evaporating during the hot pressing process. Research has shown that numerical simulations can accurately predict dehydration performance with a minimum error of 0.3% under conditions of a hot pressing time of no more than 15 seconds and a compression set of less than 60%.
However, because this process is highly dependent on material properties and process parameters, establishing a universal model remains challenging. Pulp types, additive compositions, and hot pressing conditions can vary significantly.
AGICO's Professional Equipment and Customized Solutions
As a leading domestic manufacturer of pulp molding equipment, AGICO is committed to providing customers with complete production line solutions, from raw material processing and molding to drying. Whether producing egg trays, egg cartons, or high-precision paper trays, we offer customized designs and technical support based on your raw material type and product requirements.
We believe that superior equipment must be closely integrated with scientific processes. Therefore, while AGICO provides high-performance pulp molding equipment, we also focus on training our customers' production technicians to ensure rapid production start-up and quality control.
If you are planning to build or renovate a pulp molding line, please contact AGICO for cost-effective solutions and professional support.