Titanium sponge is the raw material for titanium processing materials. Generally, they are light gray particles with a clean surface and no visible inclusions. They also include defective titanium sponge blocks, such as over-burned titanium sponge blocks, oxidized titanium sponge blocks with obvious dark yellow and bright yellow, and Dark yellow and bright yellow traces of oxidized and nitrogen-rich titanium sponge blocks, titanium sponge blocks with obvious chloride residues, titanium sponge blocks with residues, etc.   Sponge metal titanium produced by metal thermal reduction method . Purity % (mass) is generally 99.1 ~ 99.7. The total impurity element % (mass) is 0.3 to 0.9, the impurity element oxygen % (mass) is 0.06 to 0.20, and the hardness (HB) is 100 to 157. It is divided into five grades from WHTiO to MHTi4 according to the purity. It is the main raw material for making industrial titanium alloys . Titanium sponge production is the basic link in the titanium industry. It is the raw material for titanium materials, titanium powder and other titanium components. Turn the ilmenite into titanium tetrachloride , put it into a sealed stainless steel tank , fill it with argon gas , and react it with the metal magnesium to get “sponge titanium”. This kind of porous “titanium sponge” cannot be used directly. They must be melted into liquid in an electric furnace before they can be cast into titanium ingots.   basic knowledge   Sponge metal titanium produced by metal thermal reduction method. Purity % (mass) is generally 99.1 ~ 99.7. The total impurity element % (mass) is 0.3 to 0.9, the impurity element oxygen % (mass) is 0.06 to 0.20, and the hardness (HB) is 100 to 157. It is divided into five grades from WHTiO to MHTi4 according to the purity. It is the main raw material for making industrial titanium alloys. Titanium sponge production is the basic link in the titanium industry. It is the raw material for titanium materials, titanium powder and other titanium components. Turn the ilmenite into titanium tetrachloride, put it into a sealed stainless steel tank, fill it with argon gas, and react it with the metal magnesium to get “sponge titanium”. This kind of porous “titanium sponge” cannot be used directly. They must be melted into liquid in an electric furnace before they can be cast into titanium ingots.   discover history   At the end of the 18th century, the British clergyman and amateur mineralogist William Gregor and the German chemist M.H. Klaproth came from the same place in 1791 and 1795 respectively. A new element was discovered in a black magnetite sand (later learned to be titanium magnetite ) and a non-magnetic oxide mineral (later learned to be natural rutile ore), which they called “Monaquin” respectively. ” (the name of the place where titanium magnetite was found) and “titanium clay”. A few years later, it was proven that the so-called “menacun” and “titanium” found in these two minerals were actually oxides of the same element, and this new species was named after the Titans (Titans), the Hercules in Greek mythology. The element is “Titanium”.   It took 120 years from the discovery of titanium to the first preparation of relatively pure titanium metal . It took nearly 40 years from the first time pure titanium was obtained in the laboratory to the first industrial production. Many researchers made a lot of explorations and suffered failures again and again. Finally, in 1948, DuPont succeeded and produced tonnage-level sponge titanium and porous titanium.   Process and equipment   Large-scale titanium metallurgical enterprises are all magnesium-titanium joint enterprises, and most manufacturers adopt the reduction-distillation integrated process. This process is called a combined method or a semi-combined method, which realizes a closed-circuit cycle of the raw material Mg-Cl2-MgCl2 .   The reduction-distillation integrated equipment is divided into two types: inverted “U” type and “I” type. The inverted “U” type equipment is formed by connecting the reduction tank ( distillation tank ) and the condensation tank with a pipe with a valve. It is equipped with a special heating device and the entire system equipment is assembled at one time before reduction. If the system equipment of the “I” type integrated process is assembled at one time before reduction, it is called combined method equipment; and the reduction equipment is assembled first, and after the reduction is completed, the condensation tank is assembled while it is hot for distillation operation. The equipment is called a series combination equipment and is connected by a “transition section” with a magnesium plug in the middle.   Industry status   During the past 10 years of rapid development, China’s titanium industry has seriously lost control. Many places have developed titanium projects amidst the “vigorous” rush of local protectionism , resulting in a serious oversupply in the titanium market. Although the use of titanium and titanium materials has increased year after year, But it cannot change the current situation that actual production capacity is far greater than demand. For example, in 2012, although the total amount of titanium materials was more than 60,000 tons, which was a significant increase compared with the previous year, the export of titanium ingots increased significantly. The total inventory of titanium ingots of many titanium material processing companies such as Baosteel and Bao Titanium was more than 5,000 tons. In addition, the country It also purchased and stored 4,000 tons of titanium ingots. It can be seen that the domestic titanium production has increased significantly, but the demand has not increased simultaneously. On the contrary, it can be seen that the development of the foreign titanium industry is relatively rational, unlike domestic development that is “progressing” out of control.   In 2012, the economy began to recover, but China’s titanium industry market is still sluggish. However, we must not blame it for the financial crisis and the European debt crisis . Instead, we must find reasons for our own out-of-control development. Otherwise, various economic crises will It’s over, but the development crisis of China’s titanium industry, which is desperately trying to launch projects, still exists. Looking at the development route of my country’s titanium industry over the past 10 years, we can see such a cycle accompanied by labor pains: the first expansion of production → the first reshuffle → the second expansion of production → the second reshuffle… my country’s titanium industry From the development of the 1960s to 2004, both titanium and titanium material processing capacity were very small. For example, at the end of 2000, my country’s titanium sponge production was 2,000 tons. However, as the demand for titanium gradually increased at the end of 2004, by 2005, sponge The price of titanium has risen from 50,000 to 60,000 yuan per ton to 200,000 to 300,000 yuan per ton, and huge profits have begun to appear. The titanium field has quietly experienced its first large-scale expansion. In just a few years, production capacity has increased. It quickly doubled more than 60 times. After expansion, adjustment, pain, and reshuffle, the actual production of titanium sponge in my country in 2012 increased by more than 40 times compared with 2000. 

Pigments are substances that give colors to objects. Pigments are divided into soluble and insoluble, inorganic and organic. Inorganic pigments are generally mineral substances. Humans have long known the use of inorganic pigments, using colored earth and ores, to paint on rock walls and smear their bodies. Organic pigments are generally derived from plants and marine animals, such as mozambique, garcinia and purple extracted from shellfish in ancient Rome.   Introduction Pigment is a powdery substance used for coloring. It is insoluble in water, grease, resin, organic solvents and other media, but can be evenly dispersed in these media and can color the media, and has a certain hiding power. The basic requirements for pigments used in art are that the finer the particles, the better, the brighter the color, the better, and the longer it lasts without discoloration, the better (the stability is better). Watercolor paints Watercolor paints, except white, are almost all transparent. Only in this way can the needs of watercolor cover dyeing be met. Gouache paint was originally invented by adding white powder to watercolor paint to make the color opaque. Because watercolor paint is transparent, it is difficult to correct if you make a mistake. Gouache paint can be easily modified because it is opaque. Later, raw materials such as gum arabic were added to the gouache pigment to further improve its performance. Gum arabic can make the surface of gouache paint have a layer of luster after it dries. However, in special occasions where flat coating is required (such as rendering renderings and coloring animations), the glue will form irregular spots on the surface of the color, or make the color dull. It is uneven, so there are special degumming pigments. Oil paint is paint diluted with oil. Chinese painting pigments are very rich and come in various types, ranging from mineral powder to plant extraction to animal extraction, and the types are complex. Theoretically, as long as there are three primary colors of red, blue and yellow, all other colors can be mixed, but the purity of the mixed colors is always not high enough. Therefore, modern art paint manufacturers produce high-purity pigments for various hues and brightness colors. to meet various needs. From the most basic 12 colors to the usual 24 colors or even 48 colors to more than 60 colors. Special metallic colors are not included. use It is an indispensable raw material for the manufacture of paints, inks, oil painting pastes, cosmetic paints, colored papers, etc. It is also used for filling and coloring plastics, rubber products, and synthetic fiber solutions. Performance characteristics Pigments usually have the following properties: color. Color pigments are pigments that selectively absorb and scatter visible light energy and can present colors such as yellow, red, blue, and green under natural light conditions. Tinting power. The ability of a coloring pigment to absorb incident light. It can be expressed as a relative percentage equivalent to the tinting power of a standard pigment sample. Covering power. The ability of a film-forming substance to cover the surface color of a substrate. It is often expressed in grams of pigment contained in paint covering an area of ​​1 square meter. Lightfastness. The ability of pigments to maintain their original color under certain lighting conditions. Generally, an eight-level system is used, with level eight being the best. Weather resistance. The ability of pigments to maintain their original properties under certain natural or artificial climatic conditions. Generally, a five-level system is used, with level five being the best. Volatile. Mainly refers to moisture, which is generally not more than 1%. Oil absorption. Refers to the number of grams of refined linseed oil required to form a uniform mass of 100 grams of pigment. The one with the smallest oil absorption capacity is better. The oil absorption capacity is related to the specific surface area and structure of the pigment particles. water soluble matter. The water-soluble substances contained in the pigment are expressed as a mass percentage of the pigment. The water-soluble content of pigments used in paint making is often controlled below 1%. concept Pigment is a colored fine-grained powdery substance that is generally insoluble in water and can be dispersed in various media such as oils, solvents, and resins. It has hiding power, tinting power, and is relatively stable to light. It is often used in the preparation of coatings, inks, and colored plastics and rubber, so it can also be called a colorant. Pigments differ from dyes in that dyes are generally soluble in water (an old distinction), while pigments are generally insoluble in water. Dyes are mainly used for dyeing textiles and other materials. However, this distinction is not very clear, because some dyes may also be insoluble in water, and pigments are also used in pigment printing and pulp coloring of textiles. The chemical structure of organic pigments is similar to that of organic dyes, so they are usually regarded as a branch of dyes. Performance characteristics Pigments usually have the following properties: color . Color pigments are pigments that selectively absorb and scatter visible light energy and can present colors such as yellow, red, blue, and green under natural light conditions. Tinting power . The ability of a coloring pigment to absorb incident light. It can be expressed as a relative percentage equivalent to the tinting power of a standard pigment sample. Covering power . The ability of a film-forming substance to cover the surface color of a substrate. It is often expressed in grams of pigment contained in paint covering an area of ​​1 square meter. Lightfastness . The ability of pigments to maintain their original color under certain lighting conditions. Generally, an eight-level system is used, with level eight being the best. Weather resistance . The ability of pigments to maintain their original properties under certain natural or artificial climatic conditions. Generally, a five-level system is used, with level five being the best. Volatile . Mainly refers to moisture, which is generally not more than 1%. Oil absorption . Refers to the number of grams of refined linseed oil required to form a uniform mass of 100 grams of pigment. The one with the smallest oil absorption capacity is better. The oil absorption capacity is related to the specific surface area and structure of the pigment particles. water soluble matter . The water-soluble substances contained in the pigment are expressed as a mass percentage of the pigment. The water-soluble content of pigments used in paint making is often controlled below 1%. Basic classification Pigments can be divided into two categories based on their chemical composition: inorganic pigments and organic pigments. Based on their sources, they can be further divided into natural pigments and synthetic pigments. Natural pigments are derived from minerals, such as cinnabar, laterite, realgar, malachite green and heavy calcium carbonate, wollastonite, barite powder, talc powder, mica powder, kaolin, etc. Those from biological sources, such as those from animals: cochineal red, natural fish scale powder, etc.; those from plants include: garcinia, alizarin red, indigo, etc. Synthetic pigments are artificially synthesized, such as inorganic pigments such as titanium white, zinc barium white, lead chromium yellow, and iron blue, as well as organic pigments such as red pink, even light yellow, phthalocyanine blue, and quinacridone. Pigments are classified according to their function, such as anti-rust pigments, magnetic pigments, luminescent pigments, pearlescent pigments, conductive pigments, etc. Classification by color is a convenient and easy-to-use method. Thus pigments can be classified as white, yellow, red, blue, green, brown, purple, black, regardless of their origin or chemical composition. The famous “Dye Index” (ColorIndex) uses a color classification method: for example, pigments are divided into pigment yellow (PY), pigment orange (PO), pigment red (PR), pigment violet (PV), and pigment blue (PB). , Pigment green (PG), Pigment brown (PBr), Pigment black (PBk), Pigment white (PW), Metallic pigment (PM) and other ten categories. Pigments of the same color are arranged according to the sequence number. For example, titanium white is PW- 6. Zinc-barium white PW-5, lead chromium yellow PY-34, quinacridone PR-207, iron oxide red PR-101, phthalocyanine blue PB-15, etc. In order to find the chemical composition, there are other structural numbers, such as titanium white PW-6C.I.77891 and phthalocyanine blue PB-15C.I.74160, which allow manufacturers and users of pigments to identify the listed pigments. The composition and chemical structure of. Therefore, it has been widely used in the international pigment import and export trade industry, and some domestic pigment manufacturers also use this international classification standard for pigments. China’s national standard for pigments, GB/T3182-1995, also uses color classification. Each pigment color has a symbol, such as white for BA, red for HO, yellow for HU… Then combined with the code and serial number of the chemical structure, the pigment model is formed, such as rutile titanium white BA-01-03, medium chrome yellow HU-02-02, iron oxide red HO-01-01, zinc barium white BA-11-01, toluidine red HO-02-01, BGS phthalocyanine blue LA-61-02, etc. Pigments can be classified according to the types of compounds they contain: Inorganic pigments can be subdivided into oxides, chromates, sulfates, silicates, borates, molybdates, phosphates, vanadates, ferricyanates , hydroxides, sulfides, metals, etc.; organic pigments can be divided into azo pigments, phthalocyanine pigments, anthraquinones, indigo, quinacridone, dioxazine and other polycyclic pigments, arylmethane according to the chemical structure of the compound Department of pigments, etc. From the perspective of production and manufacturing, they can be classified into titanium pigments, iron pigments, chromium pigments, lead pigments, zinc pigments, metallic pigments, and organic synthetic pigments. This classification method has practical significance, and often one system can Represents a professional pigment production industry. From the perspective of application, it can be divided into paint pigments, ink pigments, plastic pigments, rubber pigments, ceramic and enamel pigments, pharmaceutical and cosmetic pigments, art pigments, etc. Various specialty pigments have some unique properties to match the requirements of the application. Pigment manufacturers can also recommend a series of pigment products to professional users in a targeted manner. acrylic paint Acrylic paint is a synthetic polymer pigment invented in the 1950s. It is made of pigment powder mixed with acrylic latex. Acrylic latex is also called acrylic resin polymerized latex. There are many kinds of acrylic resins, such as methacrylic resins, etc. Therefore, there are also many kinds of acrylic paints. Foreign pigment manufacturers have produced a series of acrylic products, such as matte acrylic pigments, semi-matte acrylic pigments, glossy acrylic pigments, acrylic matte oils, glazing oils, plastic ointments, etc. Acrylic paints are very popular among painters. Compared with oil paints, it has the following characteristics: 1. It can be released with water to facilitate cleaning. 2. Quick drying. The paint dries within minutes after being put down, unlike oil paintings that have to wait several months to be polished. Painters who prefer slow-drying paints can use retarder to delay the drying time of the paint. 3. The coloring layer quickly loses solubility as it dries, forming a tough, elastic, water-impermeable film. This membrane is similar to rubber. 4. The color is full, thick, and fresh, and it never feels “dirty” or “grey” no matter how you blend it. The colored layer will never absorb oil and cause stains. 5. The longevity of the piece is longer. The oil film in oil paintings is prone to oxidation over time, turning yellow and hardening, which can easily lead to cracks in the painting. Theoretically speaking, acrylic film will never become brittle or yellow. 6. The biggest difference between acrylic paint and oil painting in the way it is used is that it has the operating characteristics of general water-based paints and can be used as both watercolor and gouache. 7. Acrylic modeling ointment contains granular types, and there are coarse particles and fine particles, which provides convenience for making textures. 8. Acrylic paint is not very harmful to the human body. Just be careful not to accidentally eat it. 9. Acrylic paint can be used to design your own cultural shirts, which can highlight your personal personality. But it’s best to use cotton clothes and be white. It should be noted that acrylic painting should be painted on a base made of acrylic primer (GESSO), not an oil base. Material experts also do not advocate the mixing of acrylic and oil paints, especially not to paint oil paintings on an acrylic base. This is mainly for the permanent preservation of the work. There is no adverse reaction between acrylic and oil paints. When used alternately, their adhesion needs to be tested over time. water based pigments Water-based pigment is a new type of environmentally friendly pigment. Compared with traditional pigments, it has the advantages of non-toxic and odorless. Compared with traditional pigments, it is more in line with the concept of health and environmental protection, and has become a trend in pigments. Oil paints Oil paint is a special paint for oil paintings, which is made by mixing and grinding pigment powder with oil and glue. Most of them are sold in the market in tubes, but you can also make your own. Oil paint is a material entity formed by mixing and grinding mineral, plant, animal, chemically synthesized toner and the blending agent linseed oil or walnut oil. Its characteristic is that it can be dyed to other materials or attached to certain materials to form a certain pigment layer. This pigment layer has a certain degree of plasticity. It can form various shapes and marks that the painter wants to achieve according to the use of tools. texture. The various hues of oil paints are determined by the hue of the toner. Oil can make the hue of the toner slightly darker and more saturated. Chinese painting pigments Chinese painting pigments, also called Chinese painting pigments, are special pigments used to paint Chinese paintings. They are generally sold in tubes and paint blocks, but also in pigment powder. Classification of Chinese Painting Pigments Traditional Chinese painting pigments are generally divided into two categories: mineral pigments and plant pigments. Historically speaking, minerals should be used first, followed by plants, just like when using ink, pine smoke comes first and oil smoke comes later. The bright colors left on the ancient rock paintings were found to be made from mineral pigments (such as cinnabar). The remarkable characteristics of mineral pigments are that they are not easy to fade and are brightly colored. Most people who have seen Zhang Daqian’s splash-color paintings in his later years have this impression. , large areas of azurite, azurite, and cinnabar can refresh people’s spirits! Plant pigments are mainly extracted from trees and flowers. gouache paint Gouache is the abbreviation of gouache pigment. It has many names in China, such as advertising color, promotional color, etc. It is a kind of watercolor, that is, opaque watercolor paint. Because it is cheap, easy to learn and use, it is often used as an introductory painting material for beginners to learn color painting, and its usage simulates oil painting techniques. Performance of gouache Limitations of Purity and Brightness of Gouache Color When gouache paint is wet, its color saturation is as high as that of oil paint. But after it dries, due to the effect of the powder and the color losing its luster, the saturation is greatly reduced. This is its color. Limitations of Purity. The brightness of gouache is improved by diluting, adding powder, or using lighter colors with more powdery pigments. Its dry and wet changes are very large. Often some colors only add a small amount of powder. When wet and dry, the brightness will show a darker or lighter difference. This is the dry-wet reaction of gouache paint. Because the color of gouache generally becomes lighter after it dries, using the gouache well is the most difficult problem to solve technically in gouache painting. The pink color just makes the color of the picture full of the unique “pink” quality of gouache painting, and appears particularly rich in the middle color, but the color fineness of gouache painting is still far lower than that of oil painting. Due to the limitations of gouache paint, few large-scale works with higher specifications are created with gouache paint. Personality differences of gouache pigments Most colors of gouache pigments are relatively stable, such as earthy yellow, earthy red, ocher, orange, medium yellow, light yellow, olive green, pink green, ultramarine, cobalt blue, lake blue, etc. However, colors such as deep red, rose red, green lotus, and violet in gouache paint are extremely unstable, prone to color flipping, and difficult to cover. There are few types of transparent gouache colors, only a few colors such as lemon yellow, rose red, and green lotus. To draw a good gouache painting, you must fully grasp the personality of each gouache pigment and understand its color-receiving ability and covering ability. size, color and price. These issues require continuous practice so that practice makes perfect. Limitations of gouache There will be no unevenness when painting a large area. toxicology Regarding the toxicology of organic pigments it can be summarized that the pigments themselves are considered almost physiologically inert (safe), the health effects arise mainly from their dusty state (granular matter), due to their poor solubility. Organic pigments are actually not biodegradable. However, dispersants, binders, solvents, etc. may be used in the intermediate or final products of pigments. Under certain conditions, the toxicological effects of these substances should be considered. Toxicity sometimes results from degradation products. This degradation product of the pigment occurs when it is irradiated with laser light. For example, CI Pigment Red 22, 2-methyl-5-nitroaniline is produced by cleavage of the pigment by laser irradiation and the toxic krebseregende. Naming method Pigments are usually associated with a common name, a trade name or a color index of name (CI Common Name Nomenclature), as systematic nomenclature according to IUPAC (International Union of Pure and Applied Chemistry) or CAS (Chemical Abstracts Society) can result in unwieldy names. example: Common name: tender yellow Product name: Aureolin benzimidazolone yellow Protected Trade Name: Hostaperm Yellow H4G(TM) CI common name: CI Pigment Yellow 151 CAS Index: Benzoic acid, 2-[[1-[[(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)amino]carbonyl]-2-oxopropyl] Azo]

Polyvinyl chloride, referred to as PVC in English, is the third most produced synthetic polymer plastic in the world (after polyethylene and polypropylene ), with approximately 40 million tons of PVC produced annually. PVC is a polymer formed by polymerizing vinyl chloride monomer (VCM) with initiators such as peroxides and azo compounds or under the action of light and heat according to a free radical polymerization reaction mechanism. Vinyl chloride homopolymer and vinyl chloride copolymer are collectively called vinyl chloride resin .   PVC was once the most widely produced general-purpose plastic in the world and was widely used. There are two types of PVC: rigid (sometimes abbreviated as RPVC) and soft. Rigid polyvinyl chloride is used in construction pipes, doors and windows. It is also used to make plastic bottles, packaging, bank or loyalty cards. Adding plasticizers makes PVC softer and more elastic. It can be used in pipes, cable insulation, flooring, signage, phonograph records, inflatable products and rubber substitutes.   On October 27, 2017, the World Health Organization’s International Agency for Research on Cancer published a preliminary reference list of carcinogens. Polyvinyl chloride is included in the list of Class 3 carcinogens.     Main categories   According to different application scopes, PVC can be divided into : general-purpose PVC resin, high-polymerization PVC resin, and cross-linked PVC resin. General-purpose PVC resin is formed by the polymerization of vinyl chloride monomer under the action of an initiator; high degree of polymerization PVC resin refers to a resin polymerized by adding a chain extender to the vinyl chloride monomer polymerization system; cross-linked PVC resin is A resin polymerized by adding a cross-linking agent containing diene and polyene to the vinyl chloride monomer polymerization system.   According to the method of obtaining vinyl chloride monomer , it can be divided into calcium carbide method, ethylene method and imported (EDC, VCM) monomer method (it is customary to refer to the ethylene method and imported monomer method as the ethylene method).   According to the polymerization method , polyvinyl chloride can be divided into four categories: suspension polyvinyl chloride, emulsion polyvinyl chloride, bulk polyvinyl chloride, and solution polyvinyl chloride. Suspension polyvinyl chloride is the largest variety in production, accounting for about 80% of the total PVC production. Suspension polyvinyl chloride is divided into six models according to absolute viscosity: XS-1, XS-2…XS-6; XJ-1, XJ-2…, XJ-6. The meaning of each letter in the model: X-suspension method; S-loose type; J-compact type.   According to the plasticizer content , PVC plastics are often divided into: unplasticized PVC, the plasticizer content is 0; rigid PVC, the plasticizer content is less than 10%; semi-rigid PVC, the plasticizer content 10-30%; soft PVC, plasticizer content is 30-70%; PVC paste plastic, plasticizer content is more than 80%. The difference in properties between hard PVC and soft.   Physical and chemical properties   PVC is slightly yellow, translucent and shiny. The transparency is better than polyethylene and polypropylene, but worse than polystyrene. Depending on the amount of additives, it is divided into soft and hard polyvinyl chloride. Soft products are flexible and tough and have a sticky feel. Hard products have a higher hardness than low-density polyethylene. And lower than polypropylene, whitening will occur at the inflection point. Stable; not easily corroded by acid and alkali; relatively resistant to heat.   PVC has flame retardancy (flame retardant value is above 40), high chemical resistance (resistant to concentrated hydrochloric acid, 90% sulfuric acid, 60% nitric acid and 20% sodium hydroxide), mechanical strength And the advantage of good electrical insulation.   PVC has poor stability to light and heat. The softening point is 80°C and begins to decompose at 130°C. Without heating the stabilizer, PVC begins to decompose at 100°C and decomposes faster above 130°C. When heated, it decomposes and releases hydrogen chloride gas (hydrogen chloride gas is a poisonous gas), causing it to change color from white to light yellow to red to brown to black. Ultraviolet rays and oxygen in sunlight will cause photo-oxidative decomposition of PVC, thus reducing the flexibility of PVC and eventually becoming brittle. This is why some PVC plastics turn yellow and become brittle over time.   It has stable physical and chemical properties, is insoluble in water, alcohol, and gasoline, and has low gas and water vapor leakage; it can withstand any concentration of hydrochloric acid, sulfuric acid below 90%, nitric acid below 50-60%, and nitric acid below 20% at normal temperature. Caustic soda solution has certain resistance to chemical corrosion; it is quite stable to salts, but can be dissolved in organic solvents such as ethers, ketones, chlorinated aliphatic hydrocarbons and aromatic hydrocarbons.   Industrial polyvinyl chloride resin is mainly amorphous structure, but also contains some crystalline areas (about 5%), so polyvinyl chloride has no obvious melting point and starts to soften at about 80°C. The heat deformation temperature (under 1.82MPa load) is 70-71℃, it starts to flow at 150℃ under pressure and begins to slowly release hydrogen chloride, causing the polyvinyl chloride to change color (from yellow to red, brown, or even black).   The weight average relative molecular mass of industrial polyvinyl chloride is in the range of 48,000-48,000, and the corresponding number average relative molecular mass is 20,000-19,500. The weight average relative molecular mass of most industrial resins is between 100,000 and 200,000, and the number average relative molecular mass is between 45,500 and 64,000. Rigid polyvinyl chloride (without plasticizer) has good mechanical strength, weather resistance and flame resistance. It can be used alone as a structural material and used in the chemical industry to manufacture pipes, plates and injection molded products. Rigid polyvinyl chloride can be reinforced with materials.   Material processing   Polyvinyl chloride plastics come in various forms, which vary greatly, and their processing methods are also diverse, including pressing, extrusion, injection, coating, etc. The particle size, fish eyes, bulk density, purity, foreign impurities, and porosity of PVC resin all have an impact on processability; for paste resin, the viscosity and gelling properties of the paste should be considered.   PVC is an amorphous polymer with small shrinkage. The powder should be preheated before processing to eliminate moisture, enhance the plasticizing effect and prevent bubbles. Moreover, PVC is very easy to decompose, especially when it comes into contact with steel and copper at high temperatures (decomposition temperature is 200 degrees). The molding temperature range is small and the material temperature must be strictly controlled. When using a screw injection machine and a straight-through nozzle, the hole diameter should be large to prevent material stagnation in dead corners. The mold pouring system should be thick, the gate cross-section should be large, the mold should be cooled, the mold temperature is 30-60 ℃, and the material temperature is 160-190 ℃.   Below the glass transition temperature (T g , 80 ℃), polyvinyl chloride is in a glassy state; at T g → viscous flow temperature (T f , about 160 ℃), it is highly elastic and rubbery, with plasticity; at T f → thermal decomposition Temperature (T d ) is a viscous flow state. The higher the temperature, the easier the flow. When the temperature exceeds T d , PVC decomposes a large amount of hydrogen chloride (HCl), and the material loses its chemical stability and physical properties. Therefore, T d is the upper limit temperature for processing and molding. Due to the large intermolecular forces of polyethylene, Tf is very high, even close to the decomposition temperature, so plasticizers need to be added to reduce Tf. On the other hand, stabilizers also need to be added to increase the T d of PVC before it can be processed and formed.   The glass transition temperature (T g ) is only related to the molecular chain segment structure and has little to do with the molecular weight, while the viscous flow temperature (T f ) is the temperature at which macromolecules begin to move and is related to the molecular weight. The larger the molecular weight, the higher the Tf . Therefore, for some processing molding (such as injection molding), it is necessary to appropriately reduce the molecular weight of the resin. According to different molecular weights, domestic suspended polyvinyl chloride resins are divided into grades 1-7. The larger the number, the smaller the molecular weight. XJ-4 (XS-4 ) to Plasticizers reduce T f , so they are often used in the manufacture of soft products. Polyvinyl chloride with an average degree of polymerization below 1,000 is called low-polymerization polyvinyl chloride, which has better processing properties. Less plasticizer can be added during the processing, so that the product will not be accelerated due to the migration of plasticizers. Ageing. Low-polymerization polyvinyl chloride products have good transparency and are widely used in building materials, food and drug packaging materials, and as replacements for organic glass products.   PVC melt is a non-Newtonian pseudo-fluid. The greater the shear speed, the smaller the apparent viscosity, and the change is quite sensitive. When the temperature is raised, the viscosity does not decrease much. Even if the plastic is below the decomposition temperature, it will generate heat and oxidative degradation due to being at a higher temperature for a long time, which will affect its performance. Therefore, improving the fluidity of PVC melt should mainly consider increasing the shear rate (increasing pressure). In fact, increasing the external force helps the movement of macromolecules, causing T f to decrease, and macromolecules can flow at a lower temperature.   The main purpose   Vinyl chloride profile Profiles and special-shaped profiles are the largest areas of PVC consumption in my country, accounting for about 25% of the total PVC consumption. They are mainly used to make doors, windows and energy-saving materials, and their application volume is still growing significantly across the country. In developed countries, the market share of plastic doors and windows also ranks first, such as 50% in Germany, 56% in France, and 45% in the United States.   PVC pipe Among the many PVC products, PVC pipes are the second largest consumer area, accounting for about 20% of its consumption. In our country, PVC pipes were developed earlier than PE pipes and PP pipes. They have many varieties, excellent performance, and wide range of uses, and occupy an important position in the market.   PVC film The consumption of PVC in the PVC film field ranks third, accounting for about 10%. After PVC is mixed with additives and plasticized, a three-roller or four-roller calender is used to form a transparent or colored film with a specified thickness. The film is processed in this way to become a calendered film. It can also be processed by cutting and heat sealing to process packaging bags, raincoats, tablecloths, curtains, inflatable toys, etc. The wide transparent film can be used in greenhouses, plastic greenhouses and mulch films. Biaxially stretched films can be used for shrink packaging due to their thermal shrinkage characteristics.   PVC hard materials and sheets Stabilizers, lubricants and fillers are added to PVC. After mixing, the extruder can be used to extrude hard pipes, special-shaped pipes and corrugated pipes of various diameters, which can be used as sewer pipes, drinking water pipes, wire casings or stair handrails. . By overlapping and hot-pressing the rolled sheets, hard plates of various thicknesses can be made. The plates can be cut into the required shapes, and then PVC welding rods and hot air are used to weld them into various chemically resistant storage tanks, air ducts and containers.   PVC general soft products The extruder can be used to extrude hoses, cables, wires, etc.; the injection molding machine can be used with various molds to make plastic sandals, soles, slippers, toys, auto parts, etc.   PVC packaging materials PVC products are mainly used for packaging various containers, films and hard sheets. PVC containers are mainly used to produce bottles for mineral water, beverages, and cosmetics, as well as for packaging refined oils. PVC films can be used to co-extrude with other polymers to produce low-cost laminates, as well as transparent products with good barrier properties. PVC film can also be used in stretch or shrink packaging for mattresses, cloth, toys and industrial goods.   PVC siding and flooring PVC siding is mainly used to replace aluminum siding. Except for part of the PVC resin, the remaining components of PVC floor tiles are recycled materials, adhesives, fillers and other components. They are mainly used on the hard floors of airport terminals and other places.   PVC daily necessities Luggage bags are traditional products made of polyvinyl chloride. PVC is used to make various imitation leathers for luggage bags and sports products such as basketballs, footballs and rugby balls. It can also be used to make belts for uniforms and special protective equipment. PVC fabrics for clothing are generally absorbent fabrics (no coating required), such as ponchos, baby pants, imitation leather jackets and various rain boots. Polyvinyl chloride is used in many sports and entertainment products, such as toys, records and sporting goods. PVC toys and sporting goods have grown rapidly and have advantages due to their low production cost and easy molding.   PVC coated products Artificial leather with a backing is made by applying PVC paste on cloth or paper and then plasticizing it at above 100°C. You can also calender PVC and additives into a film first, and then laminate it with the substrate. Artificial leather without a backing is directly rolled into a soft sheet of a certain thickness by a calender, and then patterns are embossed on it. Artificial leather can be used to make suitcases, bags, book covers, sofas and car seat cushions, as well as floor leather, which can be used as floor coverings in buildings.   PVC foam products When mixing soft PVC, add an appropriate amount of foaming agent to make a sheet, which is foamed and molded into foam plastic, which can be used as foam slippers, sandals, insoles, and shock-proof buffer packaging materials. It can also be made into low-foaming hard PVC sheets and special profiles using an extruder. It can be used as a substitute for wood and is a new type of building material.   PVC transparent sheet Impact modifiers and organic tin stabilizers are added to PVC, and then mixed, plasticized, and calendered to become transparent sheets. Thermoforming can be used to make thin-walled transparent containers or for vacuum blister packaging. It is an excellent packaging material and decorative material.   other Doors and windows are assembled from hard special-shaped materials. In some countries, it has occupied the door and window market together with wooden doors and windows, aluminum windows, etc.; imitation wood materials, steel-substitute building materials (in the north and seaside); and hollow containers. Virtual circuit is one of the services provided by the packet switching network (the other is datagram service). Simply put, it uses the internal control mechanism of the network to establish virtual logical connections between user hosts and ensure that information can be transmitted on them. The correctness and sequence of packets, virtual circuits must be established and dismantled before and after communication. A permanent virtual circuit is a virtual circuit that is established during network initialization and remains maintained. Both X.25 networks and B-ISDN provide PVC services. PVC plastic bags are generally prohibited.          

This entry was edited and reviewed by the School of Chemical Sciences, University of Chinese Academy of Sciences , and certified by Popular Science China·Science Encyclopedia.   Ethylene glycol is also known as glycol and 1,2-ethylene glycol, referred to as EG. The chemical formula is (CH 2 OH) 2 and it is the simplest glycol . Ethylene glycol is a colorless, odorless, sweet liquid with low toxicity to animals. Ethylene glycol is miscible with water and acetone , but its solubility in ethers is small. Used as solvent, antifreeze and raw material for synthetic polyester. Polyethylene glycol (PEG), a polymer of ethylene glycol , is a phase transfer catalyst and is also used in cell fusion ; its nitrate ester is an explosive.   physical properties   Appearance: Colorless transparent viscous liquid   Melting point: -13 °C (lit.)   Molecular weight: 66.092   Boiling point: 195-198 °C   Glass transition temperature: -120 °C   Vapor pressure: 0.08 mmHg (20 ℃)   Density: 1.113 g/mL at 25 °C (lit.)   Refractive index: 1.4472 (λ: 589.3 nm; Temp: 20 °C)   Viscosity: 25.66 mPa.s (16℃)   Heat of combustion: 1180.26 kJ/mol   Autoignition point: 418 ℃   Critical temperature: 372 ℃   Critical pressure: 7699 kPa   Critical molar volume: 186 C3/mol   Eccentricity factor: 0.27   Surface tension: 46.49 mN/m (20℃)   CAS database: 107-21-1   NIST Chemical Substance Information: 1,2-Ethanediol(107-21-1)   EPA Chemical Substance Information: Ethylene glycol (107-21-1)   NIST Chemical Substance Information: 1,2-Ethanediol(107-21-1)   EPA Chemical Substance Information: Ethylene glycol (107-21-1)   Solubility: miscible with water/ethanol/acetone/glyceryl acetate pyridine, etc., slightly soluble in ether, insoluble in petroleum hydrocarbons and oils, able to dissolve calcium chloride/zinc chloride/sodium chloride/potassium carbonate/potassium chloride/ Inorganic substances such as  potassium iodide/potassium hydroxide.   At 25 degrees Celsius, the dielectric constant is 37.   t is easy to absorb moisture when the concentration is high.   Space between unit and number. Check the full text yourself later.、   chemical properties   Due to its low molecular weight and active nature , it can undergo esterification, etherification, alcoholization, oxidation, acetal, dehydration and other reactions.   Similar to ethanol, it can mainly react with inorganic or organic acids to form esters. Generally, only one hydroxyl group reacts first. By raising the temperature, increasing the amount of acid, etc., both hydroxyl groups can form esters. If it reacts with nitric acid mixed with sulfuric acid, dinitrate is formed. Acid chlorides or acid anhydrides easily form esters between two hydroxyl groups.   When ethylene glycol is heated under the action of a catalyst (manganese dioxide, aluminum oxide, zinc oxide or sulfuric acid), intramolecular or intermolecular water loss can occur.   Ethylene glycol can react with alkali metals or alkaline earth metals to form alkoxides. Usually, metals are dissolved in glycols to obtain only monoalkoxides; if this alkoxide (such as monosodium ethylene glycol) is heated to 180-200 °C in a hydrogen flow, disodium ethylene glycol and ethylene glycol can be formed.   In addition, ethylene glycol is heated with 2 mol of sodium methoxide to obtain disodium ethylene glycol. Disodium ethylene glycol reacts with alkyl halides to form ethylene glycol monoether or double ether. Disodium ethylene glycol reacts with 1,2-dibromoethane to form dioxane.   In addition, ethylene glycol is also easily oxidized. Depending on the oxidant used or the reaction conditions, various products can be generated, such as glycolaldehyde HOCH 2 CHO, glyoxal OHCCHO, glycolic acid HOCH 2 COOH, oxalic acid HOOCCOOH, carbon dioxide and water.   Ethylene glycol is different from other glycols in that the carbon chain can be broken when oxidized by periodic acid. Ethylene glycol can often be used instead of glycerin. In the tanning and pharmaceutical industries, it is used as a hydrating agent and solvent respectively.   Ethylene glycol derivatives dinitrates are explosives. Monomethyl ether or monoethyl ether of ethylene glycol is a good solvent, such as cellosolve HOCH2CH2OCH3, which can dissolve fiber, resin, paint and many other organic substances.   Ethylene glycol has strong solubility, but it is easily metabolized and oxidized to produce toxic oxalic acid, so it cannot be widely used as a solvent.   use   Mainly used to make polyester, polyester, polyester resin, hygroscopic agents, plasticizers, surfactants, synthetic fibers, cosmetics and explosives. It is also used as a solvent for dyes, inks, etc., to prepare antifreeze for engines, as a gas dehydrating agent, to manufacture resins, and as a wetting agent for cellophane, fiber, leather, and adhesives.   It can produce synthetic resin PET, fiber grade PET is polyester fiber, and bottle flake grade PET is used to make mineral water bottles, etc. It can also produce alkyd resin, glyoxal, etc., and is also used as antifreeze.   In addition to being used as antifreeze for automobiles, it is also used for the transportation of industrial cold energy. It is generally called a refrigerant. At the same time, it can also be used as a condensing agent like water. When using ethylene glycol as a refrigerant, you should pay attention to:   1. The freezing point changes with the concentration of ethylene glycol in the aqueous solution. When the concentration is below 60%, the freezing point decreases as the concentration of ethylene glycol in the aqueous solution increases. However, after the concentration exceeds 60%, as the concentration of ethylene glycol increases, the freezing point changes. As the concentration increases, its freezing point tends to rise, and the viscosity also increases as the concentration increases. When the concentration reaches 99.9%, its freezing point rises to -13.2°C. This is an important reason why concentrated antifreeze (antifreeze mother liquor) cannot be used directly and must attract the attention of users.   2. Ethylene glycol contains hydroxyl groups. When working at 80 degrees Celsius – 90 degrees Celsius for a long time, ethylene glycol will be oxidized first to glycolic acid and then to oxalic acid, that is, oxalic acid (oxalic acid), which contains 2 carboxyl groups. Oxalic acid and its by-products affect the central nervous system first, then the heart, and then the kidneys. Ethylene glycol and oxalic acid can corrode equipment and cause it to leak. Therefore, preservatives must also be included in the prepared antifreeze to prevent corrosion of steel and aluminum and the formation of scale.   Ethylene glycol methyl ether series products are high-grade organic solvents with excellent performance. They are used as solvents and diluents for printing inks, industrial cleaning agents, coatings (nitrocellulose paint, varnish, enamel), copper-clad laminates, printing and dyeing, etc. However, it is easily metabolized and oxidized to produce toxic oxalic acid, so it cannot be widely used as a solvent.   It can be used as an intermediate for the production of pesticides and pharmaceuticals, and is an intermediate for the fungicides pentoconazole and hymexazole. As well as raw materials for chemical products such as synthetic brake fluid; chemical fiber dyes for tanning, etc.   Adding ethylene glycol to hydraulic fluid can prevent oil-based hydraulic fluid from corroding the rubber in the system; water-based hydraulic fluid with ethylene glycol as the main component is an incombustible hydraulic fluid and is used in aircraft and automobiles. and molding machines that operate at high temperatures.   It is used as textile auxiliaries, synthetic liquid dyes, and raw materials for desulfurizers in fertilizer and oil refining production. Used as analytical reagents, chromatographic analysis reagents and capacitive media.   water antifreeze   Ethylene glycol is a colorless, slightly viscous liquid with a boiling point of 197.4°C and a freezing point of -11.5°C. It can be mixed with water in any proportion. After mixing, the freezing point is significantly reduced due to the change in vapor pressure of the cooling water.   The degree of decrease decreases with the increase of ethylene glycol content within a certain range. When the ethylene glycol content is 60%, the freezing point can be reduced to -48.3°C. When this limit is exceeded, the freezing point will rise instead.   Ethylene glycol antifreeze easily generates acidic substances during use , which has a corrosive effect on metals . Ethylene glycol is toxic, but due to its high boiling point, it does not produce vapor that can be inhaled into the body and cause poisoning.   Ethylene glycol has strong water absorption , and the storage container should be sealed to prevent it from overflowing after absorbing water.   Since the boiling point of water is lower than that of ethylene glycol, water is evaporated during use. When there is a lack ofcoolant , just add clean water.   This kind of antifreeze can be recycled after use (to prevent it from being mixed with petroleum products ). After sedimentation, filtration, adding water to adjust the concentration, and adding preservatives, it can continue to be used. Generally, it can be used for 3-5 years.   However, it must be filtered multiple times to prevent damage to the motor vehicle.   Many people think that the freezing point of ethylene glycol is very low. The freezing point of antifreeze is a neutral freezing point after mixing ethylene glycol and water in different proportions. In fact, this is not the case. The freezing point will be lower due to the change in the vapor pressure of the cooling water after mixing. significantly reduced.   The degree of decrease decreases with the increase of ethylene glycol content within a certain range, but once it exceeds a certain proportion, the freezing point will increase instead.   Antifreeze liquid mixed with 40% ethylene glycol and 60% soft water has an antifreeze temperature of -25°C; when the antifreeze liquid contains 50% ethylene glycol and 50% water, the antifreeze temperature is -35°C.   Freezing point measurement   Ethylene glycol is the main component of antifreeze, accounting for about 45% of the original antifreeze solution. The original antifreeze solution can be mixed with water in a certain proportion according to the temperature in various places to control the freezing point within an appropriate range. Effective antifreeze agents are various organic alcohols.   freezing point within an appropriate range. Effective antifreeze agents are various organic alcohols. Since the 1950s, almost all countries have used ethylene glycol as antifreeze. Ethylene glycol is a colorless, transparent, slightly sweet and hygroscopic viscous liquid that is misciblewith water in any proportion. When the concentration of ethylene glycol is different. The freezing point is also different. The freezing point of ethylene glycol-water antifreeze is not  linearly related to the mass fraction of ethylene glycol . The freezing point of its aqueous solution does not completely decrease with the increase of concentration. When the concentration exceeds 70%, the freezing point rises instead. During the preparation process , reasonable selection should be made based on reality to meet the requirements of antifreeze and economy . In Jiangnan , China , the ratio of ethylene glycol mass fraction is generally 40%, while in the cold north, the ratio of ethylene glycol mass fraction of about 50% is more suitable.   Packaging, storage and transportation   1. Store in a cool, ventilated warehouse. Keep away from fire and heat sources. They should be stored separately from oxidants and acids, and avoid mixed storage. Equipped with the appropriate variety and quantity of fire equipment. The storage area should be equipped with emergency release equipment and suitable containment materials. Due to its strong hygroscopicity, it should be stored sealed and sealed with nitrogen for long-term storage. Can be stored in iron, mild steel, copper or aluminum containers. However, coated steel, aluminum or stainless steel containers should be used for long-term storage.   2. The word “toxic” should be marked on the ethylene glycol container to prevent accidental ingestion and inhalation of ethylene glycol vapor. Operators should wear protective equipment and undergo regular physical examinations, especially routine urine examinations.   health hazards   Toxicity: Rat oral LD ​​50 =5.8mL/kg, mouse oral LD ​​50 =1.31~13.8mL/kg.   Routes of invasion : inhalation, ingestion, percutaneous absorption .   Health hazards : Inhalation poisoning manifests as recurrent syncope , nystagmus , and lymphocytosis. Acute poisoning after oral administration is divided into three stages: the first stage is mainly characterized by central nervous system symptoms , which in mild cases resemble ethanol poisoning , and in severe cases, rapid coma, convulsions, and death; in the second stage, cardiopulmonary symptoms are obvious, and severe cases may have pulmonary edema. , bronchopneumonia , heart failure ; the third stage mainly manifests as varying degrees of renal failure.   First aid measures Skin contact: Take off contaminated clothing and rinse with plenty of running water. Eye contact: Lift eyelids and rinse with running water or saline . Seek medical attention.   Inhalation: Move quickly to fresh air. Keep your airway open. If breathing is difficult , give oxygen. If breathing stops , perform artificial respiration immediately and seek medical attention.   Ingestion: Drink plenty of warm water and induce vomiting. Gastric lavage, diuresis. Seek medical attention. If breathing stops, perform artificial respiration immediately. Seek medical attention.   Toxicity to pets:   Ethylene glycol can be obtained from motorcycle antifreeze . The ethylene glycol in motorcycle antifreeze is not a threat to humans due to the addition of bittering agents and the small amount. However, if it is accidentally mixed with the food of pets (cats, dogs), Can cause poisoning in pets and cause kidney failure .   toxicological environment   Toxicity : It is of low toxicity.   Acute toxicity : LD 50 : 8.0~15.3g/kg (orally in mice); 5.9~13.4g/kg ( orally in rats );   Subacute and chronic toxicity : After eight days of inhalation of 12 mg/m 3 (several times in a row) in rats, 2/15 animals had corneal opacity and blindness; in humans, 9/28 inhaled a 40% ethylene glycol mixture and experienced temporary fainting ; in humans, inhalation Repeated inhalation of a 40% ethylene glycol mixture heated to 105°C caused nystagmus in 14/38 people and increased lymphocytes in 5/38 people .   Hazardous characteristics : There is a risk of combustion and explosion when exposed to open flame, high heat or contact with oxidants . If exposed to high heat, the internal pressure of the container will increase and there is a risk of cracking and explosion. Combustion (decomposition) products : carbon monoxide , carbon dioxide, water.

Gloves are hand warmth or labor protection products , and they are also used for decoration. Gloves are a very special thing. They were not originally created for practicality. Only in modern times have they become essential for thermal insulation in cold areas , or as medical antibacterial and industrial protective equipment . Gloves are divided into sewing, knitting, dipping, etc. according to the production method. But in addition to gloves in the traditional sense, today’s gloves have a deeper meaning, which is completely different from traditional gloves. This is due to the rise of online games, which has led to the emergence of overwhelming names of game equipment . Due to the large number of game players, especially compared to traditional industries, more information on gloves on the Internet is related to online game equipment. Gloves were the earliest Originated in ancient Greece .     Classification   Classification by production method   Gloves are divided into sewing , knitting, dipping, etc. according to the production method . Gloves are cut and sewn from a variety of leather, rubber, knitted or woven fabrics . Knitted gloves are made of pure or blended yarns of various textile fibers . They are knitted on a glove machine and undergo sewing processing, such as clamping , ruffing, sewing fingertips and finger forks, etc., and then go through brushing or shrinking and heat setting. Finished products. The structures of knitted gloves include plain stitch , rib, tuck , leno , etc., and the styles include plain color and yarn-dyed jacquard . Labor protection gloves are required to be relatively thick, and some are surface-coated to improve wear resistance, anti-skid, and waterproof properties. Decorative gloves need to be beautiful, and most of them undergo artistic processing such as embroidery and beading. Classification by material Gloves are divided into cotton , plush, leather, microfiber , cloth, rubber, etc. according to their materials.   Classification by finger shape   According to the shape of the fingers, they are: Split-finger gloves : Each has 5 separate long pocketed fingers; Mittens: Mengzi from Northeast China, with the thumbs separated and the remaining four fingers connected together. Three-finger gloves: The thumb and index finger are separated, and the remaining three fingers are connected together. Straight gloves: 5 fingers connected together. Half-finger gloves: each finger part is not closed, only the first section is covered. Fingerless gloves: no finger part, opening at the heel. The fewer fingers that are separated, the better the insulation effect on the fingers, but at the same time it limits the movement of the hand. In addition to decoration on half-finger and fingerless gloves, fingerless gloves also offer increased finger flexibility.   Material   Glove materials for mechanical injuries   1.(1) Metal wire – common stainless steel wire, but also chromium alloy wire, mainly used to make cut-resistant gloves. This type of material has the strongest cut resistance and is easy to clean, but it is heavy and inconvenient to use. 2.(2) Kevlar, Spectra and other synthetic yarns – are also better cut-resistant synthetic fiber materials. Although the cut-resistant ability is not as good as that of metal wires, they are lightweight and comfortable to use. And after improvement and processing, some products can also achieve cut-resistant products. The highest level of standards. 3.(3) Nitrile (with fabric lining) – has anti-wear and puncture resistance, flexible and comfortable to use. 4.(4) Natural latex (with fabric lining) – has good elasticity, is particularly flexible, and has certain resistance to wear, tear and cut. 5.(5) PVC (with fabric lining) – can provide a certain degree of wear and puncture protection. If the material is thicker, it can also have a certain degree of cut resistance, but not tear resistance. 6.(6) Leather – a natural material that has unique properties through various tanning treatments. Leather can be divided into: cowhide, which has the advantages of being comfortable, durable, breathable and wear-resistant. After chrome treatment, it is more durable and can resist high temperatures; pigskin , which has large pores, has the best breathability and can still maintain good quality after being washed. The softness without becoming hard; sheepskin is the most comfortable, most durable and has the best wear resistance, but because it is too expensive, it is generally only used in industries with higher requirements for touch.   High temperature resistant material   (1) Novoloid – a new type of high-tech synthetic fiber that does not melt, resists flames, and is resistant to high temperatures. It can withstand high temperatures up to 1100°C. It is soft and comfortable, and can resist the erosion of many chemical substances . It will not be affected even after repeated washing. Its high temperature resistance. (2) Kevlar – is a widely used aromatic synthetic fiber that is not only resistant to cuts, but also resistant to high temperature damage. (3) Aluminum-plated material – can resist radiant heat at higher temperatures . (4) Leather – if kept dry, it has good low temperature resistance . At the same time, its non-melting and non-burning characteristics make it often used to make welding gloves . (5) Cotton – is also a natural material that can properly protect against high and low temperatures. However, due to the need to meet protective requirements , the gloves are made thicker and not flexible enough.   Anti-electrical damage material   Usually electrical insulating gloves are made of pure natural latex . Latex is divided into dry glue and wet glue. Insulating gloves made of wet glue have a long processing cycle and high production costs , but the product has particularly good elasticity and is very flexible to use. In addition, due to the particularity of live work and the characteristics of electrically insulating gloves themselves, when wearing this type of gloves, you must first put on pure cotton gloves (sweat-absorbent, anti-slip), then put on latex gloves , and finally put on leather protection Gloves to prevent insulating gloves from being punctured by sharp objects. Glove Materials Resistant to Electrical Injury Electrically insulating gloves are specially designed and rigorously tested to ensure safety.   Material of chemical resistant gloves   Chemical -resistant gloves are made of a wide variety of chemicals with different properties. Special attention should be paid to selecting chemical-resistant gloves.   Natural latex – Generally speaking, natural latex has a good protective effect against aqueous solutions, such as acid and alkali aqueous solutions. Its advantages are comfort, good elasticity and flexible use.   Chlorosulfonated polyethylene – has protective properties against most chemicals, can protect against alkalis, oils, fuels and many solvents, and has good resistance to high and low temperatures, wear resistance, bending resistance, etc.   Anti-vibration gloves are usually made of three-layer structure gloves. The inner and outer layers are made of leather or soft and comfortable synthetic fiber, and the middle layer is made of silicone or other polymers that can effectively absorb vibration . Precautions in Glove Selection and Use Whether the gloves are selected appropriately and used correctly are directly related to the health of the hands.   Glove function selection   The wire gloves imported from the United States are made of stainless steel rings. Each steel ring is welded. They are fine in workmanship, comfortable to wear, strong and durable, and have good protective performance. It is widely used in: clothing cutting , floor segmentation, meat processing, bone saw operation, leather cutting, etc. The main industries include: slaughtering, meat processing, clothing factories , furniture factories, steel factories, supermarkets, etc.   Generally speaking, protection during tool opening in locations where power tools are used for cutting.   Materials and performance of anti-static gloves   Made of special anti-static polyester cloth , the base material is composed of polyester and conductive fibers . The distance between conductive fibers is 4mm. The gloves have good elasticity and anti-static properties to avoid damage to products caused by static electricity generated by the human body. It is suitable for use in the electronics industry, semiconductor , dust-free workshops and widely used in daily life. It is used in anti-static, purified and dust-free workshop environments that require the use of gloves. Wearing anti-static gloves can prevent the operator’s fingers from directly contacting electrostatic- sensitive components , and can safely discharge the electrostatic charge on the human body carried by the operator . It is necessary for workers in the semiconductor industry, optoelectronics industry, semiconductor manufacturing industry, electronic picture tube manufacturing industry, computer motherboard manufacturing enterprises, mobile phone manufacturing factories, etc. to wear it when working. Mainly used in anti-static environments that require the use of gloves, such as electronics, instrumentation and other industries.