The Influence of Lubrication on the Dyne Value in Aluminum Foil Production
2016/12/27 14:37:48
Aluminum foil is widely used in food, beverages, cigarettes, pharmaceuticals, photographic plates, household goods and so on. It is usually used as insulation material for packaging materials, electrolytic capacitor materials, buildings, vehicles, ships, houses and so on; Of the gold and silver lines, wallpaper, and various types of stationery printed matter and light industrial products, such as decorating trademarks. In these applications, the general requirements of the aluminum foil surface to be printed or composite, so the surface wetting tension value is the aluminum foil, especially the H18 state of aluminum foil (such as foil, battery foil) is a very important technical indicators.
Wetting performance and dyne value
Wetting properties
Wetting performance mainly depends on the liquid contact angle. The liquid contact angle is the angle between the horizontal line of the solid-liquid interface and the tangent of the gas-liquid interface when the droplet is not fully developed on the solid surface. angle.
The contact angle to determine the liquid on the wetting of the solid: When θ <90 ° is called wetting; θ> 90 ° is called non-wetting; θ = 0 ° or absent is called complete wetting; θ = 180 ° is referred to as completely non-wetting. θ = 90 ° is the dividing line of wetting or not.
As the surface of aluminum foil with oil generally can not be completely removed, and the surface wrinkles are not flat when its surface tension will have a great impact on the direct measurement of contact angle is not realistic, so the production practice are used to detect the dyne value to the reaction Wetting ability, the higher the value, the better the wetting performance, and vice versa, the worse the lubrication performance.
The measurement of dyne values
The dynein is a popular name, and it should be the surface tension coefficient. It is mainly to express the surface tension, that is, the force between the adjacent two parts of the liquid surface, the unit traction within the length of each other. The unit of surface tension is Newton / m (N / m) in the SI system, but dynes / cm (dyn / cm), 1 dyn / cm = 1 mN / m are still used. General requirements of finished aluminum foil wettability (dyne) ≥ 32mN / m.
The preparation method of the dyne solution
Formamide and ethylene glycol ether in accordance with YS / T455.1-2003 "aluminum foil surface wetting tension test method" to prepare, and in accordance with this method to test the value of the dyne.
In conclusion
(1) the lower the viscosity of aluminum foil rolling base oil, molecular van der Waals force is smaller, the stronger the wetting capacity, production and processing of aluminum foil surface due to the higher value.
(2) The additive content in the process lubrication has a positive effect on the dyne value. (R31) content increased with the increase of the content of Al2O3, but the increase of the content of alcohol (R 21) also increased slightly, but the effect of 6% was not significant. Acid value of aluminum foil has improved, but 1 ‰ to 10 ‰ content of the same value obtained by the same.
(3) equipment, oil leakage is less, the value will decline. However, as the amount of leakage increases, the dyne value increases. This is because, although the base oil of the long chain in the lubricating oil of the equipment is weakened by the value of the dyne, the effect of the additive in the lubricating oil on the value of the dyne is more pronounced, and when the leakage is greater than 1% Due to increased value.
(4) In general, the presence of polar molecules has a positive effect on dyne- rial (eg, leakage of additives or equipment lubricants), and the influence of base oil viscosity on dyne- eral values is relatively greater. So choose a lower viscosity base oil can be a higher dyne value. In addition, the production of aluminum foil surface there is still a certain base oil film, the use of enhanced purge, etc. This part of the base oil film away, the foil surface of the dyne value will be greatly improved.