Recycled paper made in a pulp machine.
A pulp machine is a device that takes fibrous waste material, usually from recycled newsprint or cardboard, and dissolves it in water into a paste that can then be molded and dried into new shapes, such as egg cartons. Pulp molding machines can also process cotton and other textile fibers into useful products, although most of the pulp used for containers and packaging materials comes from wood waste as of 2011. There are generally two types of approaches of packing. dry manufacturing method and thermoforming method.
Egg cartons are made from pulp machine molds.
Traditionally, pulp molding machines have been used to make recycled egg cartons and food containers for large restaurant chains. However, an increasingly widespread use of the pulp machine is to create jams or internal packaging that is molded to the object being shipped to protect it during transport. This is commercially attractive as the source materials for creating mats are cheap, environmentally friendly, and the typical pulp machine is versatile enough to create a wide range of three-dimensional shapes of pulp products.
The basic process under which a pulp machine operates is quite simple. Post-consumer and recycled paper fiber is dissolved in water in a uniform suspension and a mold is immersed in water with a screen coating on the surface. A vacuum force pulls the pulp towards the screen, filtering out the large fibers and covering the mold with a thin layer of pulp. If the machine is of a drying oven design, the mold is removed from suspension and the newly formed pulp form is separated from the mold and stored on a drying rack under controlled conditions until ready for use. The kiln-drying method can produce pulp shapes 0.06 inches (1.5 millimeters) or more thick and has a faster production cycle than thermoforming, although the final product can often contain distortion.
The pulp thermoforming machine uses a hot pressing method that molds and dries the pulp simultaneously. This type of pulping machine is more automated, so labor costs are reduced, but it also requires more precise control. The thermoforming method is most often used to create finely molded shapes with smooth surfaces, such as packaging for cell phones and electronics. It can also produce pulp forms with a thickness range as fine as 0.02 to 0.06 inches (0.5 to 1.5 millimeters).
The molding paste industry is unique in that it is naturally environmentally friendly and energy efficient. Otherwise, the raw materials for the manufacture of the pulp molds would be disposed of in landfills, and no chemical additives are needed for their use. There is also no wastewater generated in the process, since all the water used in pulping is recycled back to the cycle or evaporated. If the molds are malformed or the manufactured products do not meet standards, the material can be re-liquefied and used for new pulp molds. The kiln drying method also relies on a heated room to dry the pulp products which are often fed with additional by-products from wood waste such as sawdust.
Egg cartons have been made from pulp machine molds since 1920. Among the new products a typical pulp machine produces as of 2011 are various types of fruit trays and biodegradable pots for planting flowers or vegetables in a garden, as well as permanent pots. indoor plant containers Many containers used in hospitals are also made from cellulose so that they can be disposed of after use rather than having to be cleaned, and industrial packaging is increasingly made from cellulose, such as containers for storing light bulbs during transport.