1. Technical standards
Appearance: Transparent liquid, no suspended matter. White turbidity is allowed at low temperature.
Technical requirements are as follows:
Formaldehyde water solution, commonly known as formalin, is a colorless transparent liquid with pungent odor. According to the national standard GB/T 9009-2011, the industrial grade is divided into 37%, 44%, 50% three specifications, each class has two grades of excellent products and qualified products. Mainly used as chemical raw materials and preservatives.
2. Physical properties
Formaldehyde, chemical formula HCHO or CH2O, formula 30.03, also known as formal. Colorless gas, pungent odor, irritating to the eyes, nose, etc. The relative density of gas is 1.067(air =1), and the density of liquid is 0.815g/cm³(-20℃). Melting point -92℃, boiling point -19.5℃. Soluble in water and ethanol. An aqueous solution with a concentration of up to 55%, usually 37%, is called formalin water, a colorless liquid with an irritating odor.
This product under normal temperature and pressure is colorless transparent, volatile, flammable liquid, toxic, irritating, its steam can form an explosive mixture with air, explosion limit 7% ~ 73%, at low temperature will precipitate flocculent precipitation. Chemically, it is easy to oxidize formic acid and polymerize into polyformaldehyde. Strong reduction, especially in alkaline solutions. Can burn, vapor and air form an explosive mixture, explosion limit 7%-73%(by volume). The ignition temperature is about 300℃.
Formaldehyde can be prepared by the dehydrogenation or oxidation of methanol under the catalysis of silver, copper and other metals, and can also be separated from the oxidation products of hydrocarbons. It is used as raw material for pesticide, disinfectant, phenolic resin, urea-formaldehyde resin, Vinylon, ulotropine, pentaerythritol and dyes. Industrial formaldehyde solution generally contains 37% formaldehyde and 15% methanol, as polymerization inhibitor, boiling point 101℃.
3. USage
It is mainly used as an important raw material of intermediate and finished medicine of pharmaceutical raw materials, adhesives, chemical raw materials and preservatives, widely used in the manufacture of pharmaceutical drugs, synthetic fibers, synthetic resins, preservatives, urotropine, pentathritol, polyformaldehyde, etc.
1. Wood industry: Used for the production of urea-formaldehyde resin and phenolic resin. Urea formaldehyde resin is formed by the reaction of formaldehyde mixed with urea according to a certain molar ratio. Phenolic resin was prepared by mixing formaldehyde with phenol at a certain molar ratio. Formaldehyde's irreplaceable place in the wood processing industry is being replaced by MDI glue.
2. Pharmaceutical industry: one of the important raw materials for the production of pharmaceutical raw materials intermediates and finished drugs;
3. Leather industry: formaldehyde, as a raw material, is cheap and convenient to use.
4. Adhesive industry: Formaldehyde has strong adhesion, but also has the function of strengthening the hardness of the plate and insect prevention and anti-corrosion, so it is used to synthesize a variety of adhesives.
5. Textile industry: The application of formaldehyde in the textile industry. The use of formaldehyde is involved in the process of tree ester finishing. In textile industry, hydroxymethyl compounds containing formaldehyde are used as finishing agents in the process of textile production and processing to increase the elasticity of fabric. In order to improve the crease of fabric, cationic resin containing formaldehyde is also used to improve the dyeing fastness. The production of clothing fabric, in order to achieve anti-wrinkle, anti-shrinkage, flame retardant, or in order to maintain the durability of printing and dyeing, or in order to improve the feel, it is necessary to add formaldehyde in the additives. Cotton textiles are more used with formaldehyde printing and dyeing auxilia, because cotton textiles are easy to wrinkle, the use of formaldehyde auxilia can improve the stiffness of cotton cloth. Textiles containing formaldehyde, in the process of wearing and using, will gradually release free formaldehyde, through human respiratory tract and skin contact cause respiratory tract inflammation and skin inflammation, but also produce irritation to the eyes. Formaldehyde can cause allergies and cancer. Manufacturers use formaldehyde dyeing auxiliaries, especially some manufacturers in order to reduce costs, the use of cheap auxiliaries with very high formaldehyde content is very harmful to human body.
6. anticorrosive solution: formaldehyde is a substance released by the decomposition of formaldehyde sodium bisulfite at more than 60℃, it is colorless, has a stimulating smell, easily soluble in water. 35% ~ 40% formaldehyde aqueous solution is commonly known as formalin, which has antiseptic and bactericidal properties. It can be used to dip biological specimens and sterilize seeds, but it is easy to make the specimens brittle due to the denaturation of proteins.
The main reason why formaldehyde has antiseptic properties is that the amino group on the protein of the organism (including bacteria) itself can react with formaldehyde.
Marking, packing, transportation and storage
In a well-ventilated and dry place, the appropriate temperature is 12-25℃, not less than 10℃ storage, to avoid polymerization. Packaging: Plastic drum, 200kg per barrel or tank truck transport. Packaging containers shall be painted with strong, durable, and clear markings, including the name of the product, the name of the manufacturer, the number of this standard, and "Corrodes" and "toxic substances" as specified in GB 190; The logo. Formaldehyde solution for industrial use should be packed in dry, clean and corrosion-resistant containers. Comply with the relevant regulations on the transportation of hazardous chemicals; Should avoid touching, prevent the sun and rain. 50% grade industrial formaldehyde needs to be insulated (53 ℃~60 ℃) for transportation. Storage temperature of 37% industrial formaldehyde solution is 8℃~40 ℃; 44% industrial formaldehyde solution storage temperature of 45℃~50 ℃,50% industrial formaldehyde solution storage temperature of 53 ℃~60 ℃; Necessary measures should be taken to reduce the polymerization and oxidation of formaldehyde solution.
Safety
Danger warning: Industrial formaldehyde solution should avoid exposure to high temperature and open flame. Formaldehyde solution for industrial use has a strong pungent smell. Direct skin contact with formaldehyde can cause dermatitis and chronic poisoning. Inhaling formaldehyde gas, there will be serious irritation of respiratory tract and edema, eye tingling, headache and other symptoms.
Safety measures: industrial formaldehyde solution toxic, should minimize exposure and contact, use special care to prevent contact with eyes, skin or inhalation of excessive formaldehyde gas. If it spills into your skin or eyes, rinse with plenty of water and seek medical attention quickly.