Application of the hottest rust proof packaging in

2022-08-24
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The application of antirust packaging in the field of auto parts

1. Classification

the vapor phase antirust plastic film (hereinafter referred to as vcif) used in the antirust packaging of auto parts is divided into steel film and polymetallic film according to the applicable part materials (in China). The so-called polymetallic refers to one or more combinations of steel, copper, aluminum and steel-based coating materials (galvanized, nickel plated, etc.)

vcif made in the United States, South Korea and other countries is not classified and belongs to polymetallic film. However, their anti rust ability to steel is not as good as that of steel film in China. From the perspective of sales and management, it is easy to do without classification. But in terms of the effect of use, the classification is better. Because steel and non-ferrous metals have different environmental conditions for corrosion due to different materials, such as pH value. Therefore, the functional requirements of anti-corrosion materials are also different. Steel "likes" alkaline environment with pH greater than 9, and the environment with pH is very safe. Nonferrous metals, on the contrary, "like" neutral environment with pH value, some of which are even acidic. Their "preferences" are contradictory. The anti-corrosion of VCI is achieved by releasing the inhibitor group from the water film dissolved in the metal surface and forming a protective film on the metal surface. The nature of VCI formula components determines the pH value of water film, which should meet the pH value requirements of anti-corrosion target metal materials. In other words, the VCI aqueous solution used for steel corrosion prevention should be alkaline. vice versa. Therefore, it is pointed out that 1 # paper with vpi-260 as the main component used for steel corrosion prevention cannot be used for connecting rods with copper sleeves, zinc coated parts and aluminum pistons. So far, there has been no report of VCI that is not affected by pH value and has good corrosion prevention effect on polymetals

2. Variety

up to now, vcif has developed from the basic form of membrane to a variety of product forms

2.1 VCI foaming layer/reinforcing layer ("/" means composite)

turn the basic form of vcif into a foaming layer with a thickness of 1 0mm to increase the buffer effect. However, the strength of the film has decreased. In order to overcome this defect, the composite reinforcement layer, such as PE woven cloth, has doubled the strength of the film to meet the need for high-strength film packaging

2.2pe foaming layer/vcif

this structure is developed to increase the buffer effect of vcif without reducing the performance of vcif

2.3vcif stretch film

stretch film is more and more widely used in outer packaging. VCI is added to the stretched film to increase its vapor phase rust prevention function and create conditions for expanding its use. The use of VCI stretch film outer packaging not only increases the rust prevention and shielding effect, but also reduces the packaging volume and saves packaging wooden cases

2.4vci high resistance diaphragm

the structure of this membrane is vcif/high resistance diaphragm. When vcif with high barrier is required as the packaging shielding layer, this antirust film should be used. Commonly used high barrier films are:

EVOH (ethylene/vinyl alcohol copolymer)

PVDC (vinylidene chloride copolymer)

Pan (acrylonitrile copolymer)

2.5vci vacuum packaging film

the basic characteristic of vacuum packaging film is that the moisture permeability and air permeability are close to zero. Therefore, the use of high resistance diaphragm still can not meet the requirements, and aluminum foil must be added to the composite film. When the thickness of aluminum foil reaches μ M, the moisture permeability can reach 0

2.6vci antistatic film

when vcif is used to package electronic and electrical products, antistatic film is usually used. Add antistatic additives to vcif, so that the electrical performance indicators such as surface resistivity (Ω) can reach the ideal range, and protect electronic products from electrostatic damage

2.7 VCI foam

the thickness of VCI foam is usually mm. Strictly speaking, it does not belong to membrane. It has very good cushioning and cushioning properties. When packaging fragile and fragile assemblies, VCI foam is very suitable

most of the above products have been widely used

3. The method of using

vcif is very simple. However, several points should be pointed out

a. the pre-treatment quality of packaged parts must do a good job in rust removal, cleaning, drying and other pre-treatment of parts before rust proof packaging, ensure surface cleanliness, and pay attention to gaps and blind holes

b. the package shall be sealed with vcif antirust packaging, which shall be well sealed to avoid the loss of VCI and ensure the antirust period. The sealing method can be heat welding or adhesive tape

c. using materials Martin Martinez said, "this is the place where polydopamine (PDA) enters the game to obtain the maximum anti-corrosion effect.

d. if the dosage is enough for VCI dosage, we must master the empirical data of g/m3 packaging dosage. It can be calculated according to the size of packaging box, the area of VCI used and the unit content of VCI. The manufacturer or supplier of vcif should be able to complete these calculations for users. When it is necessary to use "In oil-free antirust packaging, in order to ensure the antirust effect, vcif is often used together with VCI powder, tablets or VCI paper.

e. try to avoid direct contact between vcif and antirust oil layer or paint layer.

f." collaborative measures "successful and advanced antirust packaging methods and cases at home and abroad have proved that it is not a single material or method to make them produce" synergistic effect ", complement each other, and achieve foolproof

4. application example

a. an auto parts company in Qingdao. Produce starting gear ring. Export to Japan

antirust packaging process: the pretreatment is coated with antirust oil and put into VCI bags, 5 pieces/bag, each of which is padded with foamed PE film and put into cartons, the vcif bags are preset on the 45 bags/box pallet, and the cartons are put into the bags on the pallet, and the 8 boxes/tray vcif bags are sealed, and the cartons are wrapped with cardboard stretch film outside the bags

note: the company uses H-shaped (steel) vcif bags, which are processed and formed by the manufacturer. Film thickness 100 μ m。

b. an automobile brake pump factory in Beijing. Produce brake pump. Domestic sales

rainbow galvanizing passivation on the outer surface of parts. Use type D (polymetallic) vcif bag, Size 120 × 140mm。

process: put the pretreatment into vcif bags, into cartons and into large cartons

c. a parts company in Mengzhou, Henan Province produces automobile engine cylinder liners, which are sold to the United States and China

export to Cummins Corporation of the United States (material: as cast bainite grey cast iron)

process: cleaning machine thermal spraying washing ultrasonic hot water washing drying or wiping dry dipping antirust oil into vcif bag, rubber band binding bag mouth packing, the box is put into vcif bag in advance, placed in layers, each layer is padded with corrugated paper with double-sided film, and each set is also sealed with corrugated paper partition tape

export to Ford company of the United States (the outer surface is sesame particles)

process: dry after washing (in the cabinet, 100 ℃, H) cool to room temperature and load it. Do you understand? If you want to know more about the details of the experimental machine, the vcif bag (double-layer, lined with VCI cardboard in the bag) is loaded into the carton in which the PE film bag is placed in advance. Desiccant is placed in the vcif bag and between the vcif bag and the PE film bag. Each cylinder liner is separated by vcif in an S-shape. A layer of VCI cardboard tape is placed on the cylinder liner to stick the vcif bag on the pallet, and 7 cases/pallet are wrapped with tensile film

note: vcif thickness: 60 μ m。

d. a parts branch of Liaoning automobile group company. It produces differential casing, flange, fork, etc., and exports products

process: pretreatment, dipping, coating, anti rust oil, draining, loading into vcif bags, removing the air in the bags, sealing into cartons by thermal welding, putting 4 bags/box into trays, and wrapping with stretched film

note: vcif film thickness: 100 μ m。

e. a diesel engine factory in Dalian. Production of diesel engine) cylinder block, cylinder head, crankshaft)

process: pretreatment, coating antirust oil, putting it into vcif bag, tape sealing

(Crankshaft) carton

(cylinder block cover) wooden box

5. The quality of vcif and its standards

the quality of vcif includes antirust performance and physical properties. When we formulated the enterprise standard and drafted the national standard (gb/t19532 has been implemented now), we collected vcif samples from the United States, South Korea, Taiwan, India, Israel and so on, and made a lot of tests. As far as the steel film is concerned, their rust prevention performance is not as good as our products; As for the film for polymetallic, the effect is similar. Korean products are slightly better than American products

in terms of physical properties, the appearance quality of domestic products is inferior to that of foreign products in some aspects

vcif quality standard:

China has the national standard of vcif: gb/t packaging materials vapor phase rust proof plastic film. In addition to the military specification mil-prf-22019d "weldable flexible and transparent shielding material treated with gas phase inhibitor" of the United States, there are no national standards reports from other countries

the formulation of China's national standard is based on the specifications of the US military. Although it is not "equivalent adoption" but "modified adoption", its overall level is not lower than the U.S. military norms. The formulation of the national standard combines the actual situation of our country, making its scientificity, applicability and operability reach the international advanced level at the end of the 1990s. It is worth pointing out that:

A. technical indicators gb/t19532 not only adopts all 15 indicators of the U.S. military specification, but also adds "alternating damp heat test" and "gas phase rust prevention screening test". The former indicator is added because vcif has been shown in the rapidly developing protective packaging of electrical and electronic products. Therefore, we will strive to highlight its advantages in the whole testing process. It is widely used and its dosage has increased greatly. This item is added to meet the needs of "basic environmental test procedures for electrical and electronic products". The latter item is added because the screening test has been widely used and recognized in the tests of domestic antirust materials, and the feedback has been adopted

b. for via test after technical parameters consumption, in the American military specification, the consumption (exposure) time of the sample is longer, which is 12 days (288 hours). It is based on the long-term storage of weapons and equipment and the severity of the storage environment, as well as the low vapor pressure of vpi-260, the main component of the VCI they use. This standard is applicable to the actual requirements of medium and short-term corrosion prevention of civil products in China, so the consumption time of samples is increased by four levels of 120h, 72h, 48h and 24h in addition to 288 hours. In this way, the original technical indicators of the U.S. military specifications are maintained, and appropriate choices can be made according to actual needs to avoid excess functions

c. via test method of vapor phase corrosion inhibition ability

via test in gb/t19532 does not adopt gb/t16267 "test method of packaging materials vapor phase corrosion inhibition ability", but formulates a new method. Its main differences from gb/t16267 are: the time and method of adding glycerin aqueous solution, the final particle size of sandpaper for grinding test pieces, the sample specification and the evaluation standard of test results. The time of adding glycerin aqueous solution adopts dintl8135 standard. Other changes are based on sufficient experiments. (end)

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