Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, packaging, decorating, writing, cleaning, filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency and security paper and a number of industrial and construction processes. The papermaking process developed in east Asia, probably China, at least as early as 105 CE, by the Han court eunuch Cai Lun, although the earliest archaeological fragments of paper derive from the 2nd century BCE in China. The modern pulp and paper industry is global, with China leading its production and the United States following.
The paper bowl is a kind of paper container made by mechanical processing and bonding of the base paper (white cardboard) made of chemical wood pulp, and its appearance is bowl-shaped. Waxed paper cups for frozen food, can hold ice cream, jam and butter, etc. Paper cups for hot drinks are coated with plastic, resistant to temperatures above 90°C, and can even bloom with water. The characteristics of paper bowls are safe, hygienic, lightweight and convenient. It can be used in public places, restaurants, and restaurants, and is a one-time item. Since the advent of paper bowls, it has quickly become the most viable green tableware in the 21st century. Internationally renowned fast food chains such as McDonald's, KFC, Coca-Cola, Pepsi and various instant noodle products have adopted disposable paper bowls. The first hygienic feature is the composition of the inner wall of the paper bowl. The reason why the paper bowl can hold water is because the inner wall of the paper bowl is coated with a layer of polyethylene water barrier film, but if the selected material is not good or the craftsmanship is not good enough. This substance may be oxidized to its volatile carbonyl compound. This substance has a strange smell, and long-term intake of this substance is very harmful, especially some small factories are still using the prohibited recycled polyethylene water barrier film; The second hygienic property of paper bowls is its degradability. An industry insider said that paper bowls not only consume resources, but also impose a great burden on the environment. Moreover, due to the convenience of paper bowls, some people throw them away after use, which not only destroys the appearance of the city, but also brings great pressure to the sanitation work. Therefore, when choosing paper bowls, we must choose paper bowls made of degradable materials, and dispose of them properly after use.
A paper cup is a disposable cup made out of paper and often lined or coated with plastic or wax to prevent liquid from leaking out or soaking through the paper. It may be made of recycled paper and is widely used around the world. The base paper for paper cups is called "cup board", and is made on special multi-ply paper machines. It has a barrier coating for waterproofing. The paper needs high stiffness and strong wet sizing. The cup board grade has a special design for the cup manufacturing processes. The mouth roll forming process requires good elongation properties of the board and the plastic coating. A well formed mouth roll provides stiffness and handling properties in the cup. The basis weights of the cup boards are 170–350 g/m2. To meet hygiene requirements, paper cups are generally manufactured from virgin (non-recycled) materials. The one exception to this is when the paper cup features an extra insulating layer for heat retention, which never comes into contact with the beverage, such as a corrugated layer wrapped around a single-wall cup.
Most paper cups are designed for a single use and then disposal. Very little recycled paper is used to make paper cups because of contamination concerns and regulations. Since most paper cups are coated with plastic (polyethylene), then both composting and recycling of paper cups is uncommon because of the difficulty in separating the polyethylene in the recycling process of said cups. As of 2016, there are only two facilities in the UK able to properly recycle PE-coated cups; in the absence of such facilities, the cups are taken to landfill or incinerated. And paper cups may have various types of lids. The paper cups that are used as containers for yogurt, for example, generally have two types of lids: heat-seal foil lids used for small "single serving" containers, and 150–200 ml (5–7 US fl oz) plastic press-on, resealable lids used for large "family size" containers, 250–1,000 ml (8–30 US fl oz), where not all of the yogurt may be consumed at any one time and thus the ability to re-close the container is required. Hot drinks sold in paper cups may come with a plastic lid, to keep the drink hot and prevent spillage. These lids have a hole through which the drink can be sipped. The plastic lids can have many features including peel back tabs, raised walls to protect the foam of gourmet hot drinks and embossed text. In 2008, Starbucks introduced shaped plastic "splash sticks" to block the hole, in some of their stores, after customer complaints about hot coffee splashing through it.
The quality of disposable paper cups on the market is uneven, and the hidden dangers are relatively large. In order to make the cups look whiter, some paper cup manufacturers have added fluorescent whitening agents. This fluorescent substance can mutate cells and become a potential carcinogen once it enters the human body. In order to achieve the water-proof effect of paper cups, a layer of polyethylene water-proof film will be coated on the inner wall during production. Polyethylene is the safest chemical substance in food processing, but if the selected material is not good, or the processing technology is not good enough, in Polyethylene may be oxidized to carbonyl compounds in the process of hot melting or smearing on paper cups. Carbonyl compounds are not easily volatile at room temperature, but may volatilize when hot water is poured into the paper cup, so people will smell strange. Although no research has confirmed what harm the carbonyl compounds released from paper cups will bring to the human body, from a general theoretical analysis, long-term intake of this organic compound must be harmful to the human body. What is more worrying is that some inferior paper cups use recycled polyethylene, which will undergo cracking changes during the reprocessing process, resulting in many harmful compounds, which are more likely to migrate to water during use. The state clearly prohibits recycled polyethylene from being used for food packaging, but because recycled polyethylene is cheap, some small factories still use it illegally in order to save costs.
Sie sind vermutlich noch nicht im Forum angemeldet - Klicken Sie hier um sich kostenlos anzumelden