PP stands for polypropylene, a type of plastic marked with the number 5 inside the recycling triangle on packaging. It’s one of the most widely used plastics in consumer products, especially food containers, and is generally considered one of the safer options for everyday use.
What Polypropylene Is
Every plastic product carries a small number inside a triangle of arrows, known as a Resin Identification Code. PP is code 5. This system helps consumers and recycling facilities identify what kind of plastic they’re dealing with. Polypropylene is a white, mechanically sturdy material that resists chemicals well, holds up under moderate heat, and costs relatively little to produce. Those qualities make it one of the most common plastics you’ll encounter at home.
Where You’ll Find PP Plastic
Polypropylene shows up in a huge range of products. Yogurt containers, deli takeout containers, ketchup bottles, beverage cups, and reusable food storage containers are some of the most familiar examples. Beyond the kitchen, it’s used in plastic furniture, luggage, toys, and household appliances.
It also plays a significant role in cars and medicine. Automakers use it for bumpers, battery cases, and interior trim panels because it’s lightweight and durable. In healthcare settings, polypropylene’s resistance to chemicals and bacteria makes it a go-to material for syringes, pill containers, bed pans, and lab equipment like Petri dishes.
Heat Resistance and Kitchen Use
One of the biggest practical reasons PP is popular for food containers is its heat tolerance. It has a melting point around 320°F (160°C), which is well above the temperatures your microwave or dishwasher will reach. Food containers made from PP won’t melt or warp in a standard dishwasher cycle, and they can handle microwave reheating at normal settings.
That said, there are limits. Polypropylene’s safe range for continuous use sits between about 32°F and 180°F (0°C to 82°C). It starts to soften around 230°F (110°C), and below 0°C it becomes brittle and prone to cracking. So PP containers work well for reheating leftovers or running through the dishwasher, but they’re not designed for oven use or prolonged exposure to very high heat.
Is PP Plastic Safe for Food?
Polypropylene is widely considered one of the safer plastics for food contact. It does not contain BPA, the endocrine-disrupting compound that raised concerns about other plastics like polycarbonate (code 7). Phthalates, another class of chemicals people worry about, are primarily used as plasticizers in PVC (code 3) to make it soft and flexible. PP doesn’t require phthalates in its manufacturing.
The FDA approves polypropylene for food contact applications. While no plastic is completely inert under all conditions, PP is resistant to fats and most organic solvents at room temperature, meaning it’s unlikely to leach chemicals into your food under normal use. Keeping PP containers out of sustained high heat (above about 212°F or 100°C) further reduces any risk of chemical migration.
How PP Compares to Other Common Plastics
The plastic you’ll see compared to PP most often is polyethylene (PE), which appears as code 2 (high-density) and code 4 (low-density). Both are considered safer plastics, but they have different strengths. Polypropylene is lighter, harder, and more heat resistant. It holds its shape better and tolerates chemical solvents and acids that would damage other materials. Polyethylene, on the other hand, is more flexible and performs better in cold temperatures.
This is why you’ll see PP used for rigid containers that need to survive a microwave, while PE tends to show up in squeezable bottles, plastic bags, and cling wrap. If you’re choosing food storage containers and heat tolerance matters to you, PP (code 5) is typically the better pick.
Can You Recycle PP Plastic?
Polypropylene is technically recyclable, but acceptance varies widely by location. Many curbside programs now accept code 5 plastics, though not all do. The recycling rate for PP has historically been low compared to plastics like PET (code 1, used for water bottles) and HDPE (code 2, used for milk jugs). Check your local recycling program’s guidelines, since what’s accepted in one city may go straight to landfill in another.
When PP is successfully recycled, it gets turned into products like broom bristles, bike racks, battery cables, and plastic lumber. Some specialty recycling programs, including mail-in options, specifically target code 5 plastics that local programs reject.
How to Identify PP on a Product
Look for a small triangle made of three chasing arrows, usually stamped on the bottom of the container. Inside the triangle, the number 5 identifies it as polypropylene. You may also see the letters “PP” printed directly below the triangle. The plastic itself tends to have a slightly waxy feel and a natural white or semi-translucent appearance, though manufacturers often add color during production.