The second most popular functional film antirust f

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Functional film II - antirust film (I)

as for functional film, there is no strict definition up to now. It generally refers to the film that has a (or some) special function that general film does not have and can meet the special needs of application, such as antistatic film, antirust film, heat shrinkable film, easy to open film, etc. Because the functional film has one or another special functions, it can better meet the needs of protecting the packaged goods, or better meet the needs of the convenience of goods, so it has a better use effect; Functional films usually have high technical content, high economic benefits and strong market competitiveness, so they have attracted much attention. Functional film is an important variety of packaging materials. It is often an indispensable material in some specific packaging fields. It plays a very important role in plastic packaging materials. In order to facilitate readers to have a preliminary understanding of functional films, a special introduction to functional films will be made here. In the future, several functional films will be introduced in this column. One of the functional films introduces antistatic films. In the next issue, surface protective films will be introduced to you. Please pay attention

antirust film, also known as vapor phase antirust film, is a functional film developed for metal antirust. To better understand the antirust film, here we first introduce the basic knowledge of metal corrosion and vapor phase antirust technology

corrosion and rust prevention of metals

in daily production and life, we use a large number of metal and alloy products. During the storage, transportation and use of metal products, corrosion often occurs, which causes great losses to people. Therefore, the corrosion and anti-corrosion of metals have also become a focus of attention. In order to effectively prevent the corrosion of metals, it is necessary to have a preliminary understanding of the corrosion principle of metals. The corrosion mechanism of metals can be summarized as follows:

under natural environmental conditions, most metals will spontaneously change from high-energy state to low-energy state, that is, from unstable metal simple substance to stable metal compound, which leads to metal corrosion. Metals often become metal ions through electrochemical or chemical reactions, and then form compounds to be corroded. In the chemical reactions that lead to metal corrosion, the existence of oxygen and water often plays an important role. The changes in metal corrosion can be expressed by the following chemical reaction formula [1]:

anode: M-E → m+

cathode: o2+2h2o+4e → 4OH - m+n+naoh - → m (OH) n

it is very important to effectively inhibit metal corrosion and prevent metal from contacting directly with oxygen and steam. Except for a few metals, such as aluminum, which will form a dense protective layer on their surface during oxidation to prevent oxygen from further contacting with the interior of the metal parts, so as to effectively protect the metal parts from further corrosion, the products of metal corrosion are generally materials with loose structure, which can not cut off the contact between oxygen and water vapor in the atmosphere and the metal. Therefore, the corrosion process will lead to the corrosion of the whole metal parts from the outside to the inside, Finally, it loses its function. In order to slow down the speed of metal corrosion and reduce the losses caused by metal corrosion, people often paint some electronic tensile testing machines in the current market with coatings such as reducer or electroplating to separate the surface of metal products from oxygen, water vapor and other substances in the atmosphere during use, so as to effectively protect the metal; Before the storage and transportation of metal products and other metal parts, the method of coating grease is often used to protect the metal surface to avoid direct contact with oxygen, water vapor and other substances in the air during storage and transportation, so as to achieve the purpose of rust prevention, and then clean the grease with solvent before use. However, such a rust prevention method requires a lot of manpower and material resources, The solvent may also cause harm to the environment, which is very unfavorable to environmental protection. The development and application of vapor phase antirust agent and antirust film have opened up an ideal way for the packaging, storage and transportation of metal products, so they are highly valued and welcomed by the industry

vapor phase rust prevention technology

plays a variety of roles such as dragging, straightening and stabilizing tension; The vapor phase antirust technology such as roller type (divided into horizontal type and vertical type) is a new antirust technology based on the application of vapor phase antirust agent. VCI (vapor corrosion inhibitor) for short. Vapor phase inhibitor is also called vapor phase inhibitor (VPI). The solid vapor phase rust inhibitor is volatile at room temperature. Like camphor, naphthalene and other substances, the chemical composition of steel can change greatly at room temperature, and it can continuously volatilize and fill the whole packaging container. The vapor phase antirust material plays the role of rust prevention through the vapor phase inhibitor. The vapor phase inhibitor is continuously and slowly vaporized at room temperature, and finally can always be in a "saturated" state in the confined space. The volatilized inhibitor steam is adsorbed on the exposed metal surface, thus forming a stable protective film with a thickness of one to two molecules. The protective film can effectively prevent the corrosion of metals by oxygen, moisture and other environmental atmospheres, Thus, it plays an excellent anti rust role. Because the vapor phase inhibitor molecule is continuously volatilized, it can achieve long-term and stable rust prevention effect. At the same time, the vapor of the inverter of Jinan gold testing machine, a vapor phase rust inhibitor, can also passivate the metal surface by reacting with metal ions, forming a passive film complex, changing the acid-base environment of the metal surface and forming a hydrophobic film on the metal surface. Due to its attachment to the metal surface, it plays a role in protecting the metal, so as to prevent or delay the corrosion of the metal

the vapor phase rust inhibitor can be made into ingot or powder and placed in the packaging bag for direct application. It can also be made into antirust film or antirust paper and paper plastic composite materials with plastic or paper as the carrier for antirust packaging of metal parts

introduction to vapor phase corrosion inhibitor

vapor phase rust inhibitor is a compound with sublimation and rust prevention at room temperature and a mixture with this compound as the main component

according to different chemical compositions, vapor phase rust inhibitors can be divided into inorganic compounds and organic compounds. Inorganic compounds, such as ammonia, ammonium carbonate, ammonium bicarbonate, ammonium chromate, diammonium phosphate, etc; Organic compounds, such as amine salts and esters of organic acids, organic phenols and their derivatives, organic heterocyclic compounds, salts of organic amines and inorganic acids, etc; Vapor phase corrosion inhibitors can also be classified according to the size of vapor pressure. Those with low vapor pressure can be called L type, and those with high vapor pressure can be called H type; Vapor phase corrosion inhibitors can also be classified according to their uses, and those used for steel, non-ferrous metals and their assemblies are class L; Special for iron and steel is called class 2 (see jiszl519-1973 vapor phase rust inhibitor)

basic characteristics of gas phase inhibitor

the form of gas phase inhibitor is not limited to solid, but can also be liquid, but generally must meet the following conditions:

(1) it has appropriate volatility

(2) good chemical stability

(3) it has certain solubility in water

(4) good anti rust ability

(5) low toxicity and non toxicity

(6) no abnormal reaction to plastic, paper and other carriers

some common vapor phase rust inhibitors

⑴ diisopropylamine nitrite (vpi-220)

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