Many items used in the kitchen are made of plastic, and this guide displays the different types and their suitability for certain uses.
Plastics are primarily made from petrochemicals, the main ingredient of
which is oil.
The term "plastics" encompasses organic materials, such as the elements carbon (C), hydrogen (H), nitrogen (N), chlorine (Cl) and sulfur (S), which have properties similar to those naturally grown in organic materials such as wood, horn and rosin.
Plastic can be classified into thermoplastics and thermoset plastics. Thermoset plastic is heat resistant and can be used for cooking. Thermoplastic plastic is vulnerable to heat, and can be recycled and reformed repeatedly.
There are about two dozen important types of plastic, with many variations. The plastics with which we are most familiar are listed in the chart below, together with their recycling symbol, their individual strengths, and their most common uses.
|PET or PETE
|Plastic soft drink and water bottles, beer
bottles, mouthwash bottles, cooking oil and salad dressing containers,
boil-in food pouches, processed meat packages
Clear and optically smooth surfaces. Excellent barrier to oxygen, water, and carbon dioxide. High impact capability and shatter resistance. Excellent resistance to most solvents. Capability for hot-filling.
No known hazards. Do not reuse, as surface is porous and hard to clean.
high density polyethylene
|Milk jugs, detergent bottles, oil bottles, toys, plastic bags
Excellent resistance to most solvents. Higher tensile strength compared to other forms of polyethylene. Relatively stiff material with useful temperature capabilities.
No known hazards.
(chlorine and ethylene)
|Food wrap, vegetable oil bottles, blister packaging, as well as plastic
pipes and outdoor furniture
High impact strength, brilliant clarity, excellent processing performance. Resistance to grease, oil, and chemicals.
Possible interaction when plasticizers (phthalates, DEHA) are added for greater flexibility. Possible dioxin pollution in manufacture and incineration.
low density polyethylene
|Bread and produce bags, frozen food bags, squeezable bottles, storage
containers, tote bags, bottles, clothing, furniture, carpet, shrink-wrap,
garment bags, trash can liners
Excellent resistance to acids, bases, and vegetable oils. Toughness, flexibility and relative transparency for packaging applications using heat sealing.
No known hazards.
|Margarine and yogurt containers, caps for containers, wrapping to replace
cellophane, drinking straws, cutting boards
Excellent optical clarity in biaxially oriented films and stretch blow molded containers. Low moisture vapor transmission. Inertness toward acids, alkalis and most solvents.
No known hazards.
(benzene and ethylene)
|Egg cartons, fast food trays, disposable plastic silverware, drinking
cups, packaging pellets (Styrofoam peanuts)
Excellent moisture barrier for short shelf life products. Excellent optical clarity in general purpose form. Significant stiffness in both foamed and rigid forms. Low density and high stiffness in foamed applications. Low thermal conductivity and excellent insulation properties in foamed form.
Styrene is a suspected carcinogen, and p-nonylphenyl, a suspected endocrine-disrupting chemical. Do not consumer fatty foods or alcoholic substances in Styrofoam containers.
Recyclability is based on individual plastics and the collection practices of each municipality.
(Some types are listed below)
|This code indicates that the item is made with a resin other than
the six listed above, or a combination of different resins.
Items classified in this category are dependent on resin or combination of resins.
|Cookware, plumbing tape, tubing
Excellent heat resistance. Excellent chemical resistance. Almost frictionless.
|Saran and other food wraps
Excellent impermeability from food odors. Excellent flexibility.
A type of PVC, potential for pollution during manufacture and incineration.
|Most clear plastic baby bottles, 5-gal water bottles
|Plastic baby bottles
|Resins based on corn, potatoes, sugar cane and other starch-based
No known hazards.
Durable against impact, high mechanical strength.
|Packaging, parts, electronics, ropes, brushes
High abrasion resistance, low friction, high tensile strength.
|Plexiglas, Lucite, Acrylite
Hard and extremely clear.
|Pan handles, toaster knobs
Hard, strong, inexpensive. Excellent electrical resistance.
|Dishware and utensils, electrical components, laminated veneers
Very good heat-, scratch-, and stain-resistance.
Plastics are controversial because of their environmental impact in both manufacturing and disposal, and some are also controversial in use. Although plastics are essential in our daily lives, we can limit their negative impact by using non-disposable alternatives, when available, and by recycling.
American Chemistry Council
- Plastic Packaging Resins (PDF 119KB)
- Facts on Plastics
- Plastics in Everyday Products
U.S. Environmental Protection Agency
- Profile of the Plastic Resin and Manmade Fiber Industries (PDF 2.06MB) Includes history of plastics, method of manufacture, and lots more.
Biodegradable Products Institute