Quick Answer
Yes, most chewing gum contains plastic polymers. The main ingredient in gum base is polyisobutylene, a synthetic rubber polymer. Other plastic polymers like polyvinyl acetate (PVA) and polyethylene are also commonly used as gum base ingredients. While not literally made of plastic, gum base contains similar synthetic polymers.
What is Chewing Gum Made Of?
Chewing gum is made up of the following basic ingredients:
- Gum base – 20 to 40%
- Softeners – 0 to 20%
- Sweeteners – 5 to 60%
- Flavors – 1 to 5%
- Colorings – 0 to 0.1%
The gum base is the most important part of chewing gum. It gives gum its unique chewy texture and allows it to retain flavor. Early gums were made with natural gum bases like chicle, a tree sap harvested from the sapodilla tree. However, most modern gums use synthetic gum bases made of plastic polymers.
Gum Base Ingredients
Common plastic polymers used to create synthetic gum bases include:
- Polyisobutylene – Also called PIB, this is the main component of most gum bases, making up 10 to 40%. It provides elasticity and chewability.
- Polyvinyl acetate (PVA) – Used at 5 to 30% of gum base. Adds texture and softens the gum.
- Styrene-butadiene rubber (SBR) – Used at up to 15% to improve elasticity.
- Polyethylene – Adds texture and softness at up to 5%.
- Paraffin wax – Used up to 5% to soften the gum base.
Other natural ingredients like resins, fats, and emulsifiers are also used in smaller amounts in gum base. But synthetic plastic polymers form the majority.
Why is Plastic Used?
Synthetic plastic polymers are used to create gum bases because they have properties ideal for making chewing gum:
- Flexibility – Plastics like polyisobutylene are extremely flexible and elastic.
- Moldability – The polymers can be molded into sticks of gum.
- Consistency – They allow consistent texture and chewing performance.
- Shelf stability – Plastics resist changing texture or becoming hard over time.
- Water insolubility – Gum base won’t dissolve during chewing like natural gums.
- Flavor encapsulation – The polymers trap and gradually release flavors.
Natural gums like chicle have some of these desirable properties. But synthetic plastics can be produced more consistently and tailored to get the perfect gum texture and performance. This allows gum to be mass-produced with a long shelf life.
Health and Environmental Concerns
While plastic polymers are ideal functionally for chewing gum, some health and environmental concerns exist:
Digestion
The human body cannot break down synthetic plastic polymers. Most pass through the digestive system unchanged before being eliminated. Very small amounts may be absorbed. The health effects of this are uncertain but likely minimal.
Toxic Ingredients
Some older synthetic rubber polymers used in gum like polyvinyl acetate (PVA) and styrene-butadiene rubber (SBR) can contain trace amounts of toxic monomers like styrene and vinyl acetate. Levels today are very low due to improved manufacturing.
Plastic Waste
Being indigestible, discarded gum ends up as small microplastics polluting the environment. Gum waste is very hard to remove from pavements and costs millions per year. An estimated 375 million pounds of gum are chewed annually worldwide.
Making Gum Base Plastic-Free
There is increasing interest in making gum base from more natural and sustainable ingredients as an alternative to plastics:
Chicle
Chicle is a tree sap that was the original chewing gum base used by the Mayans. It is still harvested today in small amounts. Chicle gum is considered more natural but doesn’t have ideal elasticity.
Latex
Natural latex from rubber trees can be used as a gum base. It produces a good chewy texture but has less stability than synthetic polymers.
Gum Arabic
Gum arabic is an edible gum harvested from acacia trees. It is being studied as a possible natural gum base ingredient.
Other Natural Gums
Researchers are also testing other sources of natural gums, like jelutong, perillo, and lemongrass as gum bases. These show promise but can be difficult to extract.
Recycled Plastics
Some companies are developing gum bases using recycled synthetic plastics, like recycled rubber from tires. This reduces plastic waste.
Can You Buy Plastic-Free Gum?
While most gums today contain synthetic plastic polymers, there are some plastic-free, all-natural gum options:
- Simply Gum – Made with chicle, candelilla wax, and other natural gums.
- Chicza – Uses chicle harvested sustainably from rainforests.
- Pur Gum – Uses natural latex gum base.
- Boon Natural Gum – Made with chicle and candelilla wax.
However, these plastic-free gums only make up a very small share of the market currently. Major mainstream gum brands like Wrigley and Trident still use synthetic gum bases. As more research develops into alternative natural bases, plastic-free gums may become more widespread.
Types of Plastic Used in Different Gums
While most gums use similar plastic polymer ingredients, the specific amounts vary between gum brands and products. Here is an overview of some of the key gum products and plastic polymers they contain:
Bubble Gum
- Higher amounts of SBR rubber to make the gum extra elastic and bubble-blowing.
- Higher levels of PVA to increase softness and stickiness.
- Less polyisobutylene since less chew resistance is needed.
Breath-freshening Gum
- Moderate levels of polyisobutylene for chewability.
- Higher amounts of softeners like glycerin to release flavors.
- Extra polymers to encapsulate and gradually release flavor oils.
Chewing Gum
- Higher percentages of polyisobutylene to create firm, rubbery texture.
- Moderate amounts of resin to bind the gum together.
- Less softeners to maintain chew resistance.
Nicotine Gum
- Typically higher amounts of softeners like glycerin or lecithin to release nicotine.
- Extra polymers and emulsifiers to encapsulate the nicotine.
- Moderate gum base levels since it dissolves faster.
How Gum Base Plastic is Made
Producing the synthetic polymers for gum base involves advanced manufacturing processes:
1. Polymerization
The base polymers are created by combining and reacting various monomers, often using heat and catalysts in large chemical reactors. For example, polyisobutylene is made by polymerizing the monomer isobutylene.
2. Mixing
The different polymers, waxes, resins and other ingredients are measured out and mixed together in precise proportions by industrial blending machines. This creates the final gum base compound.
3. Extrusion
The uniform, dough-like gum base is fed into extruders which force it through openings that shape and cut it into long strips or pellets for packaging.
4. Conditioning
Before packaging, the gum base may be heated and conditioned to achieve the desired texture and moisture level.
5. Packaging
The gum base is sealed into moisture-proof packaging to prevent drying and sent to gum factories for use in chewing gum manufacturing.
Making Chewing Gum with Plastic Polymers
Here is an overview of how chewing gum is made using the synthetic gum base:
1. Mixing
The gum base is melted and blended with sweeteners, softeners, flavors and colors in large mixers to make the final gum.
2. Extruding
The warm, liquid gum mixture is extruded out into thin sheets onto long conveyor belts.
3. Cooling
The sheets of gum are cooled and conditioned, which causes the gum base to solidify into a firm, chewy texture.
4. Cutting
The sheets are fed through cutting machines which stamp out the individually wrapped stick shapes.
5. Wrapping
The sticks are wrapped in foil or paper packaging as they convey through the wrapping machines.
6. Packing
The wrapped gum sticks are inspected, packaged into larger boxes and palletized for distribution and sale.
Conclusion
While not literally made of plastic, most chewing gum contains a gum base made of synthetic rubber and plastic polymers like polyisobutylene, polyvinyl acetate, and styrene-butadiene rubber. These plastics provide the unique chewy, stretchy texture gum is known for. However, some natural gum base alternatives exist like chicle, latex, and other plant resins. As research on these continues, plastic-free gums may become more available. But for now, the majority of gum products contain plastic. So if you’re wondering “is there plastic in gum?” – the answer is yes.