Discussion on the key technology and production pr

Discussion on key technologies and production problems of vapor phase antirust plastic film (Part I)

Abstract: This paper expounds the history of the development of vapor phase antirust plastic film, which is about 1/3 lower than the level of traditional concrete residential buildings of about 740 kg/m2, and introduces the use form, application field, manufacturing method, problems existing in the production process, technical indicators, as well as the current standards of this product at home and abroad

key words: vapor phase antirust plastic film vapor phase inhibitor antirust packaging plastic film key technology

I Overview: history of vapor corrosion inhibitor plastic film

vapor corrosion inhibitor film (vcif) is a protective inner packaging material formed by adding vapor corrosion inhibitor (VCI) or vapor phase inhibitor (VPI) to the plastic film in a certain way. Vapor phase antirust plastic film (commonly known as VCI film) is mainly prepared by chemical synthesis, screening vapor phase inhibitor (VCI) with high temperature (200 ℃) stability and suitable vapor pressure, and mixing it with PE in the form of ultra-fine powder to produce plastic masterbatch with high VCI content, which is added to polyolefin resin and prepared by CO extrusion blow molding process

compared with other anti rust packaging materials, it has the characteristics of transparency, flexibility, sealing and welding, processing and molding, high barrier, beauty, convenience and economy. Its production and development history is later than that of vapor phase antirust paper. The first formula about this kind of use form was published by the United States in 1958 [1], which was not converted to industrial production at that time. Japan also announced a similar formula in 1962. It was not until 1963 that France successfully produced the first patented product published by the United States, called "clear Pak" film. In the same year, the United States published a patent for the second formula. It was not until 1970 that patents on the manufacturing methods of such materials appeared in Japan. The formula of vcif for non-ferrous metals was first published in Britain in 1973 [2]. Since then, West Germany, the former Soviet Union, Belgium, Brazil, France, Israel and other countries have published patents on the formulation and manufacturing methods of such materials, with Japan and the United States accounting for the most. From the perspective of practical application, the United States has been used for a long time; Japan studied earlier but applied less, which has been rarely seen so far; South Korea began to contact vcif in 1993, and now it has reached the international advanced level; Southeast Asia, Taiwan and other markets are basically agents of American companies' products

in China, Wuhan Institute of material protection began to develop vcif[3] in the 1970s, and made great achievements. After comprehensive testing, the technical indicators of the pilot products reached the then U.S. military vcif product specifications. After more than three years of industrial trial, the effect was obvious. In 1992, Zhu Yefeng applied for the patent of coated vcif [4]; In 1999, Cao Haichuan obtained the patent of blow molding vcif [5]; In 2000, Shenyang antirust packaging material company proposed two new forms of vcif, expanding its application range

II. Basic principle

12. Good fusion with 372 plexiglass Metal corrosion mechanism

metals will spontaneously change from high-energy state to low-energy state under natural environmental conditions, that is, from unstable metal simple substance form to stable metal compound form. This change is called metal corrosion, that is, the destruction or deterioration of metals caused by chemical or electrochemical reactions under the action of environmental media, The corrosion mechanism is shown in Figure 1: the changes in the figure can be expressed by the following reaction formula:

anode: M-E → m +

cathode: O 2 + 2H 2O + 4E → 4OH -

nm + NaOH - → mm (OH) n

metal gradually turns into metal ions, and then forms compounds and is corroded

2. Vapor phase rust prevention mechanism

in order to prevent metal corrosion, it is necessary to protect the metal. The most commonly used storage and rust prevention treatment method for metals and their products in modern times is the vapor phase inhibitor method. The main application form of vapor phase inhibitor is to add vapor phase inhibitor to a certain form of packaging materials to form vapor phase rust prevention packaging materials. The most commonly used is the vapor phase antirust paper based on paper and paper/plastic. The VCI plastic film developed in this project is a new type of VCI packaging material with renewal significance. The basic principle of this project is to organically combine modern vapor phase inhibitor technology with plastic processing technology, so that the vapor phase inhibitor can be evenly and stably mixed into the plastic film, and the inhibitor steam can be continuously and stably volatilized through the characteristics of the vapor phase inhibitor itself - appropriate steam pressure. This inhibitor has high temperature resistance, humidity resistance, wear resistance, oil resistance, chemical corrosion resistance, good electrical insulation performance, good thermal performance The corrosion agent vapor passivates 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, so as to prevent or delay the occurrence of metal corrosion

III. thin structural form of vapor phase antirust plastic

vcif can be divided into various forms according to its structure, function and manufacturing process, and has its own characteristics and scope of application. At present, there are two types: coating type and extrusion blow molding type. The coated film is made of polyethylene, polypropylene or other plastic film as the carrier, and the adhesive, VCI and solvent are evenly coated on the corona treated film and dried. The production method is similar to that of vapor phase antirust paper. The products produced by this method have the following advantages: VCI has a wide selection range, good rust prevention effect, and is not limited by high temperature; Rapid rust prevention in the early stage; The production technology is relatively simple. At the same time, there are also the following shortcomings: poor appearance uniformity; Poor transparency; The coating is easy to be rubbed off and stick to the metal products or suffer losses; The drying of solvents (such as ethanol, toluene, gasoline, etc.) consumes energy and causes certain environmental pollution. This method was fully studied as a basic method in the early stage of vcif. With the emergence of CO extrusion blow molding method, the research and application of this method will stay at a certain degree and scale. During this period, although someone carried out research on a similar method - printing vcif and obtained a patent, it was also limited to the scope of scientific research and widely used. At present, the film produced by this method is only produced by printing in large professional manufacturers at home and abroad. Extrusion blow molding is formed by mixing VCI directly into plastic particles and co extrusion blow molding, or by granulating VCI and co extrusion blow molding with plastic particles. Compared with coated products, it has the characteristics of high transparency, clean appearance, beautiful appearance and easy processing. It is the mainstream of vapor phase antirust plastic film today. The disadvantages are that the rust prevention effect is slow in the early stage, VCI is easy to vaporize, liquefy or deteriorate in the production process (155-20, in which the upper device of the moving beam has a lower jaw 0 ℃), which affects the manufacturing process and rust prevention effect, less barrier than the coating type, easy to condense, etc. With the improvement of VCI synthesis level, the expansion of its scope, the development of corresponding additives and the adjustment of its structure, the above problems will be greatly improved, and will be further studied and applied as one of the main products of antirust packaging materials in the coming decades