How to choose the right valve for aerosol? (science)
According to the British Aerosol Manufacturers Association (BAMA), today there are more than 200 aerosol products used in the personal, home, industrial, agricultural, construction, fire, safety, medical and other fields.
Aerosol valve looks insignificant, but relative to the whole aerosol product is the most important thing, not only related to the sealing of the product, but also related to the ejection effect, of course, also related to the stability of the whole aerosol product. Therefore, how to choose the appropriate valve is worth attention in the development of aerosol products.
Ninety percent of valves used in North America are manufactured by Percision, Seaquist and Summit, with the rest manufactured by Newman-Green,Bespak, Beardg, Emson, Riker and Coster. Seaquist morphed into the Aptar Group, which acquired Emson in 1999. Well-known suppliers in the market also include Lindal,Mitani, etc. And the domestic valve mainly comes from the United States, precision, cimB and other manufacturers.
If from the valve category, aerosol is mainly divided into two categories: one and two. One yuan aerosol main structure includes: tank, valve, outer cover, push button, projectile agent, material body. The main results of binary aerosol include: tank, valve, multilayer aluminum bag, outer cover, push button, material body, compressed gas.
Valve usually includes: sealing cup, outer gasket, inner gasket, stem, spring, valve chamber, straw and other seven parts, taking into account different materials, size and structure and other factors, the theory of the valve can present tens of billions of different changes.
Therefore, how to choose the right valve needs to consider the following factors:
First: one dollar valve or binary valve?
In the mixture of the material and the projectile agent, the compatibility of the material formula should be considered. When the projectile agent and the content are sprayed at the same time, it is easy to produce that the projectile agent has been sprayed, and the material body still remains, which affects the consumer experience. Can not be used 360 degrees, can only be used in front or upside down. Volatile parabolic agent (propylene butane or dimethyl ether), the pressure will increase geometrically with the increase of temperature, belongs to dangerous goods, transportation and storage conditions have strict requirements.
Regardless of cost, binary valves have many advantages: for example:
The contents do not directly contact the aerosol tank, forming protection to the material body;
All-round ejection, adapt to the diversified consumption scene;
Vacuum valve bag before filling, can also be irradiated by cobalt 60 disinfection, the formula can reduce preservatives, reduce allergenic source;
Constant pressure in the tank, stable ejection, low material body residue;
With compressed air or nitrogen, the pressure is almost constant as the temperature increases, and the requirements for transportation and storage are relatively low
Second: the choice of sealing cup material?
Iron cups are usually 0.27mm thick and aluminum cups are 0.42mm thick. Personal care applications often use aluminum cups, which are more stable and less prone to corrosion. The size stability of iron cup is better, and it is not easy to be affected by the tank or cup sealing process;
Third: gasket material
Gaskets are usually divided into internal gaskets and external gaskets, materials are various, mainly: butyl, chloroprene, butyl, chloroprene, nitrile, chloroprene, polyurethane and so on. Gasket shrinkage will affect stem gasket fit, sometimes leading to leakage. If the gasket expands excessively, the valve stem hole of the gasket cannot be exposed when the nozzle is pressed, which will affect the injection efficiency. After repeated trials, gold was tested with a mixture of 75% ethanol and 25% isopentane, and the best choice was the relatively stable rubber of NEOPRENE and BUNA.
Fourth: stem aperture
Common sizes are 0.35, 0.4, 0.46, 0.51, 0.61mm, and the number of stem holes is one of the determinants of gushing rate. The number of stem holes is also available in different series, with 1,2,4,6 and even 8 holes.
Fifth: beside the valve hole
The gas phase side hole is located on the valve chamber body, and is located inside after the valve is sealed. It is mainly used to increase the atomization effect, increase the stability of the content ejection of some powder products, and increase the ejection of high viscosity products. Available in single and double hole designs.
Number six: Straw length
In the initial setting can be based on valve length = total height of the jar - set value. The final valve length should be at the bottom 1/3 of the semi-circle at the bottom of the tank after the bottom of the straw is stabilized by soaking.
Considering that straws have a 3-6% expansion, it is important to confirm the length after compatibility testing, and of course a bevel cut straws design can also help slightly.
With appropriate buttons, the selected valve can deliver the characteristics of the aerosol to the consumer. As a package scheme for a complex product, it needs compatibility and stability testing to design an amazing product!
Post time: Mar-23-2022
