Packaging Styles - Bottle Caps


PET bottles, small Boston Rounds, glass jars, shampoo bottles and bottles of wine all have one thing in common.  Each requires a cap to create a reliable seal and protect the product within.  While you may be familiar with the standard screw cap - think bottled water or soft drinks - pay attention the next time you are in the grocery store and you may be surprised at the number of different closures available for your product. When choosing you cap, keep in mind that the type of capping equipment available for use will also depend on your choice of cap. 


Screw caps are generally threaded caps that require torque to be tightened onto various container types.  However, there are many variations of the screw cap, from simple flat caps to trigger sprayers.  Both spindle capping machines and chuck cappers will normally handle screw caps, with a few exceptions.  The choice of capping machines will depend on your cap, your container and your production requirements. 


A flat cap is a screw cap with a flat top. Flat caps are most commonly found on bottled water and soft drinks.  Spindle cappers and chuck cappers both work well with flat caps and the decision between the two capping machines may simply come down to speed. 


A sports cap is also a screw cap but without the flat top.  Instead, the sports cap will twist or pull up to allow a restricted flow of product from the bottle, often requiring a squeeze on the bottle.  Some bottled water is marketed in these types of containers, as are certain energy drinks such as Gatorade.  Sports caps will also work with either spindle or chuck capping machines, though special chucks or chuck inserts may be necessary for the extended tops of the sports caps. 


A flip-top cap is very similar to a flat cap, the main difference being that the cap will be "flipped" open, rather than unscrewed, to access the product.  Ketchup bottles and salad dressing containers often utilize flip top caps.  As the caps will be closed when they are introduced to the container and torque is applied, flip-top caps, like flat caps, will work with both spindle capping machines and chuck cappers. 


A press top cap is a screw cap that can be pressed on one side and will pop up on the other.  Body washes and shampoos are popular products for press top caps. These caps are more or less a variation on the flip top caps and also work well with spindle cappers and chuck capping machinery. 


A unique screw cap is the trigger sprayer, found on many glass cleaners and other household products.  This screw cap basically includes a straw and sprayer that allows a product mist to be shot from the closure.  The trigger sprayer can easily be tightened down using a spindle capping machine, but presents some problems for the chuck cappers.  The capping head on a chuck capper normally descends over the entire cap, and then applies torque to create the seal.  The large trigger and spray head make this impossible, making the spindle capper the logical choice for these types of closures. The spindle capper, rather than descending over the cap, uses spinning discs and contacts the edge of the cap to apply the torque.  

While there are other variations of the screw cap, those listed above currently reign as the most popular.  Similarly, though the screw cap seems to be the closure of choice in today's packaging world, other closures do exist. 


Wine bottles, vials, perfume and a number of other products may use a bottle stopper or a cork to seal the product.  Bottle stoppers may be plastic, glass, rubber or a number of other materials.  The capping machines used to create a seal with these caps will also depend on the cap, container and production requirements.  Many corks and bottle stoppers can be securely sealed with a snap capping machine.  The snap capper will normally use either a snap belt with a gradual decline to push the cap into place or a press on head that "stomps" the closure into place as the cap and container pass under it.  The cap and container material will help determine whether a belt or press on head should be used.  A snap capper can also be combined with a spindle capping machine for unique caps or for facilities that use a variety of cap types when sealing their containers. 


ROPP stands for roll-on pilfer proof, and ROPP caps are a unique cap in the packaging industry.  These caps are widely used on wine bottles as well. ROPP caps require a specific machine to create the seal.  A ROPP capping machine is manufactured with special knives for the bottle being run. These knives carve threads into aluminum blanks based on the threads on the bottle.  ROPP caps allow for tamper evidence and a consistent, secure seal. Normally, a capping head can be obtained for a ROPP capper that will allow plastic screw caps to be run on the machine as well, offering a versatile capping machine. 

While capping machinery exists for all of the above mentioned cap types, choosing the correct capping machine for your unique bottle, cap and product combination can increase efficiency and productivity.  If you would like to learn more about cap types or capping machinery, contact a Packaging Specialist at Liquid Packaging Solutions toll free today.