Everyone probably knows that paper first appeared in China – its “trial version” was made from bamboo, hemp and even silk, which was considered fabulously expensive and was not available to everyone. The discoverer of this paper, which we still use today, was Cai Lun – he noticed that bamboo paper is very heavy and silk is simply unprofitable to produce, and it gets wet quickly. It was then that Cai Lun was appointed an advisor and tasked with coming up with a cheaper and more affordable method of production.
What a surprise, but the wasps gave him the right idea! He took a closer look at their nests, which they built from dead wood, plant fibres collected in the neighbourhood and their own saliva, which not only made the material strong, but also protected it from moisture. He decided to use mulberry bark, hemp bark, old fishing nets and mulberry fibres as well as rags and wood ashes. He ground all the ingredients, soaked them and set them in a frame with a bamboo sieve, then dried them in the sun and smoothed them out with stones. Thus the first sheet of paper was born and the process of perfecting and simplifying the technology was set in motion.
Over the years, manual labour was completely replaced by automation, and today machines are responsible for making paper, but the basic principles and method of selecting raw materials have not changed that much. The basis for all paper products is a vegetable long-staple pulp that is mixed with water to form a homogeneous, soft mass from which both a sheet and a long paper strip can be formed. Pulp pulp from natural wood is predominantly used; paper based on annual plants (rice, hemp) is less common – it has an increased whiteness.
Tree trunks are delivered whole to the mills, where they are stripped of bark, cut, and shredded. The type of paper you use depends a lot on what type of wood was used. For example, pine and cedar, as very soft woods, are used to make flexible wrapping paper. Oak and maple make very smooth paper, while Canadian spruce is strong and very flexible. For book paper, a mixture of oak and pine is more commonly used. Interesting fact: It takes 5.6 cubic meters of wood to make one ton of paper, but taking into account the average volume of a log (about 0.33 cubic meters) to produce a ton of paper you need as much as 17 trees. And one tonne of paper can already produce around 30,000 standard school exercise books.
stages of paper prodaction in a factory sitting
1. Raw material preparation and sorting
The wood is delivered to the mill and peeled of bark and then cut into chips, which are sorted by size on special sieves.
2. Processing and cooking
The sorted chips are then ground into fibres. Mechanical processing is the most economical method, but it is principally used in newsprint production because the pulp fibers are very short and the strength of the paper web is low. Chemical pulverization of the pulpwood produces longer fibers and stronger paper, by feeding the wood chips into a pulping machine with acid. The pulp is then filtered and washed to remove impurities.
3. Fibre forming, addition of additives and dyeing
The fibre pulp is sent to a special machine which reshapes the shape and structure of the fibre, and then blended with adhesives to make it resistant to moisture, or with resins to work with water inks.
The paper is then coloured using pigments or dyes. The addition of a coating agent (such as kaolin) is very popular – it makes for smooth, opaque paper for printers and plotters. The paper is then fed to a papermaking machine.
4 Processing in a papermaking machine
The pulp obtained after dyeing is placed on a fabric fixed on continuously rotating rolls – it is on this fabric that the virgin paper web begins to form during the process. This is achieved by removing water and compacting the fibers.
Raw cellulose sliver is rolled over a system of rollers which first squeeze out the water, then dry the sheet and then polish it.
In this section the paper is fully dewatered and compacted to its maximum and then sent for rewinding.
7. Winding and cutting
The finished ribbon is reeled up into huge rolls which are sent to the slitting unit where they are cut into individual sheets of a certain size, cheque tapes, or wadding, stacked and packed.