How Latex Balloons Are Made: General Overview
THE NATIONAL LATEX PRODUCTS COMPANYOVERVIEW OF HOW BALLOONS ARE MADE
Balloons are manufactured from a liquid rubber called latex. The balloon gets its color from the pigment that is added to the latex. Pigments are both organic and inorganic compounds that absorb certain wavelengths of visible light and reflect others. For example, a red balloon is red because the balloon absorbs all the visible light except red frequency light which is reflected back to the eye. The strength of balloons can be affected by the pigment if the pigment particle is large in size and interferes with the film continuity and if the pigment reacts with any of the other ingredients in the balloon. As far as which color has the most effect on the balloons strength, we have not done any in depth study. Since we use pigments that are water dispersions of very, very, small particle size, and they do not react with any other ingredients in the latex, we do not detect any difference.
The natural rubber latex that we use comes from the sap of the rubber tree , Heveabrasiliensis, that grows in Malaysia. This sap looks like milk and is shipped to America in large ocean tanker ships. Once removed from the tree, the sap is called latex. To make this suitable for balloon production, curing agents, accelerators, oil, color, and water must be added. After these are added, the completed latex is put in an open top tank, and the balloon form, which is in the shape of a balloon, is dipped. Before the form is dipped into latex, it is dipped into a coagulent that causes the rubber particles of the latex to collect on the form. This coagulent is calcium nitrate, water, and/or alcohol. After the coagulent coated form is dried, it is then dipped into the compounded latex. Then the latex coated form passed through a set of revolving brushes that rolls the balloon neck into the bead that is used to aid in the inflation of the balloon. The latex coated form is then washed in hot water to remove any unused nitrate. Following the leaching, the form is put in a 200-220 degrees Fahrenheit oven to cure for 20-25 minutes. When cured, the rubber balloon is removed from the form (stripped).
Photo copied from the Latex Engineering B.V., a company that has been producing balloon and other product dipping lines for over 50 years. The following information is taken from the Latex Engineering web site: A good balloon has the following conditions: regular peripheral wall thickness, good end gelation, pinhole free, good bead rolling, and a 'favourable' taste. The above are controlled by: surface tension control of coagulant and good antisettling of 'chalk', even speed immersion and withdrawal with still liquid surface, correct compound viscosity and correct chemical stability, clean formers and efficient filters good step back of film thickness, well-leached film, and dryness state chemically friendly formula.
An even latex film depends upon a consistent coagulant deposit. This, in turn, depends upon a fast drying time and an even speed of withdrawal from the coagulant (which implies a hot coagulant and former). With small time cycles leading up to the coagulant dip, it is important not to lose heat necessarily after the stripping.
For making a balloon, the formers pass the following stages:
- acid bath needed once every eight hours (or after every round )
- clean water bath of constantly refreshed water
- brushing, especially the former bottom
- warming the bath up to 70 to 80 degrees Celcius
- first coagulant bath, for beading the edge of the balloon
- second coagulant bath for the balloon (the temperature of both coagulant baths is 70 degrees Celcius)
- oven for drying coagulant
- latex dip (former is leaving the bath upright in a good sliding angle - system of batch dipping - to prevent drop forming on the end of the balloon
- oven for setting latex film
- beading
- leaching
- detack tank
- two ovens with a temperature 80 to 90 degrees Celcius, other (higher) temperatures possible
- cooling down by two fans
- stripping by air and rollers
The following questions apply to the manufacturing of latex balloons.
- Q: Is the balloon manufacturing process all automated?
- A: It is largely automated these days.
- Q: How much does a typical balloon cost to produce?
- A: Each balloon size and type will have a different cost. It's a combination of the amount of latex used, and how easy it is to automate the process. 260's are harder to make than 11 inch rounds.
- Q: After the molds are dipped into the latex, how does the balloon come off its mold? (manual removal or automated process?)
- A: It depends on the size and shape of balloon. Some are completely automated. Some are stripped manually (with the help of forced air/water on the form). I believe all current latex manufacturers can strip all of their round balloons automatically.
- Q: This question may sound weird, but can you bond/fuse two balloons together, or say, two dried strips of latex together?
- A: This is getting into an area I know less about. I can tell you from experience that balloons can stick together if heat is applied, but they dont' hold together very well and can be pulled apart. During manufacture, if you stick them together prior to curing them, they will fuse. This is what happens with the 6-inch hearts and 260's that are stuck together at the tips. the forms are too close together on the racks that get dipped, so after dipping, they sometimes touch each other and join. I believe inner tubes and tires are butyl rubber (because it is oil resistant), you can probably glue latex balloons together using tire patch cement. It comes in little tubes all the way up to gallon cans. Heat is used in some types of tire patching (hot patches).
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