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What is a pencil?

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in 1564, a black mineral graphite was discovered in barodale, England. Because graphite can leave traces on paper like lead, which is much darker than lead, graphite is called “black lead”. At that time, shepherds in barodale used graphite to mark the sheep. Inspired by this, people cut graphite blocks into small strips for writing and painting. Soon, King George II simply took the barodale graphite mine into the possession of the royal family and made it a royal patent. Writing it with a graphite strip will not only dirty your hands, but also break easily. In 1761, the German chemist Faber first solved this problem. He washed the graphite with water to turn it into graphite powder, then mixed it with sulfur, antimony and rosin, and then formed the mixture into strips, which is much more tenacious than pure graphite strips and is not easy to dirty his hands. This is the earliest pencil. Until the end of the 18th century, only Britain and Germany could produce this kind of pencil in the world. Therefore, after Napoleon Bonaparte launched the war against neighboring countries, Britain and Germany cut off the supply of pencils to France. Therefore, Napoleon Bonaparte ordered French chemist Conde to find graphite ore in his own land and make pencils. However, the quality of graphite ore in France was poor and its reserves were small. Conde mixed clay into graphite and barbecued it in a kiln to make a good and durable pencil lead in the world at that time. The hardness and color depth of the pencil lead produced by adding different proportion of clay into graphite are also different. This is why we see H (hard pencil), B (soft pencil) and Hb (pencil with moderate hardness) marked on the pencil today. The task of putting a wooden coat on a pencil was done by American craftsman Monroe. He first built a machine that can cut out wooden strips, then carved a slot on the wooden strip, put the pencil lead into the slot, and then align and bond the two wooden strips. The pencil lead is tightly embedded in the middle. This is the pencil we use today. The refill made of graphite or clay with pigment is used as the writing medium. It is a writing or painting tool for learning, office, engineering drawing, art, painting, various marks, etc. In ancient Greece and Rome, lead rods similar to pencils were made of lead metal. This kind of pen is mostly made into a cone. It uses lead to rub with other objects to leave traces of lead, which can be used for marking. In the 14th century, similar modern pencils appeared in Europe. Dutch painters used them to paint on paper. Italians used a mixture of lead and tin to make lead rods for painting and writing. In 1565, there were diagrams drawn with pencils in the German C. gersner’s collection, and recorded the words “for drawing and notes, people made refills with lead and other mixtures, and then attached wooden handles to draw lines…”. In the same year, Britain began to make the most primitive wooden pencil by hand with graphite as the refill. In 1662, the world’s first pencil factory, shidelou pencil factory, was built in Nuremberg, Germany. In 1761, German F. Custer founded Faber Custer pencil factory in Nuremberg. Sulfur and antimony were used as binder and heated and mixed with graphite to make lead core, which made a big step forward in pencil manufacturing technology. From 1790 to 1793, French N.J. Kant first adopted the method of washing graphite with water to improve the purity of graphite, and bonded graphite with clay to make refill. This method is called Kant method. Kant pencil factory was established in 1793, which laid the foundation for modern pencil industry. In 1932, China established the first Dahua pencil factory in Kowloon, Hong Kong. Since then, Beiping China pencil company and Shanghai Huawen pencil factory have been built successively, both of which are semi-finished product processing plants. In 1934, a Chinese standard domestic pencil factory was established in Shanghai, began to make lead cores and began to study the use of domestic raw materials to make pencils. After the founding of the people’s Republic of China, large-scale pencil factories with an annual output of 150-250 million pieces have been built in more than 10 cities such as Harbin, Beijing, Tianjin, Jinan, Dalian, Fuzhou, Shenyang and Bengbu. Lead core manufacturing and painting, printing and decoration technology have also been continuously improved, and all plastic pencils, resin fine lead cores and fine core movable pencils have been developed. We have developed new equipment such as glue plate bundle clamp dryer, automatic painting machine, electric tunnel core burning furnace, lap board machine and various packaging machines
[edit this paragraph] classification
according to the nature and purpose, it can be divided into three categories: graphite pencil, color pencil and special pencil. Graphite pencil lead is a pencil with graphite as the main raw material. It can be used for drawing and general writing. The hardness mark of graphite lead is generally “H” for hard pencil, “B” for soft pencil, “HB” for pencil with moderate hardness and “F” for pencil with hardness between Hb and H. Graphite pencils are divided into 18 hardness grades such as 6B, 5b, 4b, 3b, 2b, B, Hb, F, h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h and 10h. The larger the number in front of the letter, the harder or softer it is respectively. In addition, there are 7b, 8b and 9b3 grades of soft pencils to meet special needs such as painting. A colored pencil with a lead. The lead core is composed of clay, pigment, talc powder, adhesive, grease and wax. Used for marking symbols, drawing, drawing charts and maps, etc. Color pencils are usually packaged in sets (6, 12, 24, 36, 64 colors). Special pencils include glass pencils, color changing pencils, carbon drawing pencils, drawing pencils, watercolor pencils, pastel pencils, etc., which have their own special uses. ① Glass pencil: the lead is composed of pigment, grease and wax. It is used for writing or marking on the surface of glass, metal, enamel, ceramics, leather, plastic, plexiglass, etc. for industrial, pharmaceutical, national defense, survey and other departments. There are red, white, orange, light yellow, purple, dark green, light blue, black and other colors. ② Color changing pencil: commonly known as copy pencil. The lead core contains dyes such as sun resistant green lotus lake, and the writing can not be erased with an eraser. It is suitable for writing important documents and recording accounts for a long time. There are green lotus, red, blue, green, yellow and other colors, mostly green lotus. ③ Carbon pencil: also known as carbon pencil. The lead core is made of clay, charcoal powder, carbon black, etc. Used for painting and oil painting. ④ Blueprint pencil: also known as tracing pencil. Graphite lead core is treated with red dyes such as oil soluble wax red to block out light. It is used for direct printing after drawing. ⑤ Watercolor pencil: the lead core is added with water-soluble acid red and other acid dyes. When the lead core is stained with water, it is like watercolor pigment. It is used for photo coloring, sketching, drawing maps, statistical charts and so on. ⑥ Pastel pencil: the lead core is made of pigment and porous and soft raw materials (such as calcium carbonate), free of grease and wax. Its hardness and writing feel are similar to chalk. For painting
[edit this paragraph] raw materials
pencil raw materials mainly include pencil rod materials, graphite lead core materials, color lead core materials and appearance decoration materials. The materials for pencil rod mainly include wood and adhesive. Wood is used to make pen holder. It requires upright texture, fine and uniform structure, soft or slightly soft, slightly brittle, less resin, low moisture absorption, small expansion and shrinkage and no deformation. There are mainly pencil cypress (red cypress), cedar, cedar, basswood, alder, etc. The adhesive shall have proper viscosity, fluidity and wettability. After hardening, the adhesive layer has to
ughness, little damage to the tool, certain water resistance, heat resistance and aging resistance, easy curing at room temperature, short hardening time, non-toxic, etc. There are mainly animal glue, polyester acid vinyl lotion, hot melt glue, etc. Graphite lead core raw materials and auxiliary materials include graphite and clay. Graphite is a colorant. Using its greasiness and plasticity, it is made into lead core, which can draw black marks, firmly adhere to the paper, and can be wiped off with an eraser. Graphite with high carbon content and fine particles shall be selected. Clay is used as binder to bond graphite particles by using its plasticity and cohesiveness. Clay with good plasticity, low iron content and wide sintering range is required. Auxiliary materials include molding materials and materials that change the properties of lead cores. Molding materials are used to improve plasticity and adhesion, and improve the molding performance of lead core. Commonly used maltose, Astragalus gum, etc. Change the performance of lead core materials for oil immersion treatment after lead core sintering, so as to improve the physical properties of lead core (such as wear, concentration, stress on core tip, smoothness, hardness, etc.). Commonly used are paraffin, tallow, Vaseline, etc., which are usually used in combination with two or more. Color lead core raw materials include pigment, physical raw materials, adhesive, grease and wax. Pigments (including pigments and dyes) play the role of coloring, which requires good coloring power, high hiding power, soft quality, high fineness, good heat resistance, non-toxic, etc. Commonly used are titanium dioxide, carbon black, phthalocyanine blue, etc. Physical raw materials play the role of bonding, skeleton and adjusting hardness. The appearance decoration materials mainly include nitrofiber pencil paint, printing ink, electrochemical aluminum foil, rubber head and aluminum hoop. The manufacturing process can be divided into pencil board, lead core, pencil rod, finished product decoration and other processes. In pencil board processing, the log is disintegrated and cut off, and sawed into wood blocks. After hydrothermal treatment, it is cut into pencil board by board cutting machine. The plate is 184mm long, 73mm wide and 4.8 ~ 5.2mm thick. After heating (60 ~ 120 ℃) drying and high temperature (130 ~ 200 ℃) denaturation treatment, the pencil board is softened and easy to curl. Lead core processing graphite lead core is prepared by mixing graphite and clay in a certain proportion, mixing by kneading machine and three roller machine, extruding lead core with a certain specification and size (such as HB ~ 3H lead core diameter of 1.80 ~ 2.10mm) through core pressing machine, heating (50 ~ 150 ℃) drying and high temperature (800 ~ 1100 ℃) roasting to make it have certain mechanical strength and hardness, and finally oil immersion treatment. The color of lead core is similar to that of graphite lead core, but sintering is not required. There are two processing methods: one is to mix clay, talc powder, adhesive, pigment, grease and wax evenly, and then form and dry them, which is called mixing method; The other is made by mixing porcelain clay, talc powder, pigment and adhesive evenly and extruding them into lead core, or putting the dried lead core in the oil core container to fully absorb grease at a certain temperature, which is called oil immersion method. For pencil rod processing, the pencil board is planed into a groove board with a thickness of 4.1 ~ 4.2mm and a core groove corresponding to the diameter of the lead core with a grooving machine, and then the lead core and the pencil board are glued together with adhesive. After heating (50 ~ 120 ℃) and drying for 1 ~ 8 hours in the clamped state, the white rod pencil with a length of 178 ~ 180mm is processed by the rod planer. Appearance decoration processing: the white pencil will be painted and printed for decoration, as well as polished, printed trademark, rubber head and other processing to make it a finished pencil with certain specifications, appearance colors and patterns
[edit this paragraph] types
these indicate the hardness of the pencil, which is determined according to the hardness of the center of the pen. From soft to hard, they are 6B, 5b, 4b, 3b, 2b, B, Hb, h, 2h, 3h, 4H and 5h respectively, 6h B — black blackness h — hard hardness the more the number of B, the darker and softer the pencil, the harder the number of H, and the lighter the color Hb is intermediate Pencil specifications are usually represented by H and B. “H” is the beginning letter of English “hard”, which indicates the hardness of the pencil lead. The larger the number in front of it, the harder the lead and the lighter the color. “B” is the first letter of English “black”, which represents the composition of graphite and indicates the soft condition of pencil lead and the obvious degree of writing. The larger the number in front of it, the thicker and darker the color. The following table lists the resistance of different types of pencil lead

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