As a chemical processing company in Melbourne, one of the many industries we service is paper manufacturing. Paper may seem like a mundane daily item until you realise the extraordinary process for it to get to your table. It is common knowledge that paper comes from trees, but how does it transform from wood into the object we use as a writing surface? Chemicals are an essential part of the process that allows paper to take on the properties we desire and require.
Step 1: From wood to mulch:
Paper begins its journey at the felling of a tree. Trees are cut down into logs and stripped of their leaves and branches. To obtain a uniform texture, the bark is removed as the logs are placed into a rotating drum machine which completes this process. From here, the logs are mulched into small woodchips. Compared to logs, these are smaller, and each has significantly more surface area, making the chemical breakdown process in the next step more efficient. Another benefit of the woodchip’s small size is that they are easy to transport in bulk and funnel through any equipment.
Step 2: The paper mill and chemical processing
The chips move on to the next ‘pulping’ stage. This stage usually occurs at a dedicated paper mill and processing plant rather than at the logging site. Here, they are combined with an acidic chemical processing solution at high temperatures to dissolve the lignin in the wood and extract cellulose fibres. The paper breaks down into a gooey, chunky paste, composed almost entirely of cellulose, rather than a series of individual wooden chips. The paste allows it to be more malleable, without it flowing everywhere like a liquid. This process is called the ‘kraft process’ and the acidic solution is a combination of water, sodium hydroxide and sodium sulphide.
Step 3: How does paper become white?
Following the Kraft Process, the fibres are washed and then bleached to give the paper the white colour we are familiar with. Bleaching can involve a process of chlorine bleaching (chlorine & hypochlorite). However, more environmentally friendly alternatives (chlorine dioxide & sodium chlorate) or chlorine-free bleaching (oxygen and hydrogen peroxide) are commonly used. The pulp’s physical appearance and texture have taken on more familiar Paper-Mache-like characteristics. From here, the paper fibres are dried, split into sheets and baled, making them suitable for transport if required. At this stage, pulp sheets can be used to make a variety of paper products such as tissues and cardboard, so the sheets are often transported to dedicated mills that create these specific products.
Step 4: Obtaining the structure of the paper
The pulp fibres are once again mixed with water and fillers such as clay and calcium carbonate. At this stage, the paper pulp has now taken on a liquid consistency, but the additives give the paper an opaque physical appearance. Other chemicals such as epichlorohydrin, melamine and urea-formaldehyde are used to give the paper extra strength. These chemical processing additions polymerize the paper, allowing it to maintain structural integrity after it is wet. Cationic starch is also applied to the wet pulp to help increase the interconnections between the paper fibres.
Step 5: Paper sheet formation:
The paper-chemical compound is once again dried and released through a paper-making conveyor belt machine. The filter on the machine releases a flat sheet of the paper compound through a conveyor belt operating at 80-90km an hour. This allows the fibres to spread thin into a sheet-like format. From here, the sheets are pressed and squeezed to release as much water as possible and flatten, before drying once again. At this stage, the pulp has undergone enough chemical processing and physical processing to be labelled as paper. The sheets are wound up into a giant roll and the dried paper is dry enough not to adhere to itself. Given the diverse needs of paper users, the giant rolls are divided to match client requirements. This process includes cutting the roll into individual sheets, colouring, and coating.
Does your paper company need chemical processing?
Paper has a complex manufacturing process and requires a variety of chemicals and formulas to achieve the quality of the product desired by consumers. Melbourne Chemical Packers are experienced with handling and chemical processing quotes for a variety of industries including paper manufacturing. If your business requires a custom chemical manufacturing company, then you have arrived at the right place.
Does your business require chemical processing? Send us a quote via our website contact form today or phone us on 03 8316 2019 for further information.