Wrapping Paper Manufacturer

brown wrapping paper is a paper produced by the process called kraft pulp. It is very strong and relatively coarse. Kraft paper is usually brown. It is used for brown paper bags , packaging, envelopes and other packaging. The kraft paper is widely available in both sheets and rolls, but rolls are the most commonly used.

Kraft paper is manufactured using a technique called kraft process, kraft or sulphate process and describes the technology of converting wood into pulp composed of almost pure cellulose fibers. The process involves treatment of wood chips with a mixture of sodium hydroxide and sodium sulfide that break the bonds between lignin and cellulose. The name derives from the Kraft process German word that means strength or power.

Kraft process was developed by Carl Dahl in 1879 and a paper mill using this technology began in Sweden in 1890. The invention of the recovery boiler by GH Tomlinson in the early 1930s, was an important step in advancing the kraft process. It allowed for the recovery and reuse of inorganic chemicals, such as pulp mill kraft pulp is almost closed with respect to inorganic chemicals, except those used in the bleaching process . For this reason, in the 1940s, the kraft pulping process has exceeded the sulfite as the dominant method for the production of wood pulp.

Wood chips are introduced into vessels called digesters, which are capable of withstanding high pressures. Some digesters operate in a batch and others in a continuous process, as the digester Kamyr. The digesters produce 1,000 tons of pulp per day and more common with the greater production of more than 3,500 tons of pulp per day. Wood chips are impregnated with cooking liquor. The cooking liquor consisting of black liquor and hot white liquor. The hot black liquor is the spent cooking liquor from the explosion. white liquor is a mixture of sodium hydroxide and sodium sulfide, produced in the recovery process. In a continuous digester the material is fed at a rate that allows the reaction pulping ends when the output of the reactor equipment. delignification It usually takes several hours at 130-180 ° C. Under these conditions, the lignin and hemicellulose degradation to give some fragments that are soluble in strongly alkaline liquid. The solid pulp (about 50% by weight based on dry wood chips) are collected and washed. At this stage, the pulp is brown and is known as a brown background. The combined liquid, known as black liquor, containing fragments of lignin, carbohydrate decomposition of hemicellulose, sodium carbonate, sodium sulfate and other minerals.

The kraft paper is used today not only in rolls and sheets, but also in paper bags.