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Most plastic housewares are either- thermoplastic or thermosetting plastic.


Kitchen storage items and food preparation utensils are examples of thermoplastics which include rigid or flexible polyethylene, nylon, vinyl and acrylics.

In the manufacturing process, heat and pressure are applied to dry materials in a mold. The finished product melts when re-subjected to heat, making thermoplastics unsuitable for cooking utensils. In fact, these items should never be left near an open flame of a hot stove where they may come in contact with direct heat. However, containers made of “boilable plastic” can be taken directly from the freezer and dropped into boiling water.

Some thermoplastics are rugged enough to withstand severe weather extremes and the constant battering that trash and garbage cans take. These are found in plastic cans that are lighter weight than good metal cans and won’t crack, dent, warp or rust.


During manufacturing, thermosetting plastics become hard and brittle with the application of heat and pressure. The product retains its rigid form regardless of subsequent applications of heat. Melamine, phenolic, urea, plastic-laminated and fiberglass-reinforced materials are made this way.

Thermosetting plastics are primarily used for appliance knobs and handles, bottle caps, radio and TV cabinets, laminated countertops and melamine dinnerware. Probably the most familiar use is for heat-resistant handles on metal cookware.

Although thermosetting plastics are not affected by moderate heat, you should not inadvertently leave a detachable pot handle or melamine dinner plate near intense or direct heat. While they will not melt like thermoplastic, they may warp.


Plastics-even the best-should be washed with a mild soap or nonabrasive cleaner. Abrasive cleaners and scouring pads may permanently mar the finish. Solvents and liquid cleaners may etch the finish of some plastics, notably polystyrenes.

Today, many plastics are “boil- proof” or safe for washing in an automatic dishwasher, but you should still read the manufacturer’s fact tag or label before washing the item.


Virgin plastic is one big quality difference. Less expensive products may be made from reclaimed plastic, which may dry out and crack-virgin plastic won’t. Better quality is apparent in weight of the item and thickness of walls, sides and bottoms. Also, look for a snug seal in lids.

Plastics Glossary
Acrylic-warm to touch. Available in translucent, transparent and opaque colors. Resists sharp blows, but scratches easily. Can be damaged by perfume, gasoline, cleaning fluid, etc. Has slow burning rate; will not flash ignite. Phenolic-thermosetting plastic with good resistance to heat. Used for handles on cooking pans, etc. Can be boiled.
Acrylonitrile-rigid material with high resistance to heat, breaking and shattering. Can be crystal, transparent or opaque. Polyethylene-lightweight, thermoplastic that feels waxy; is resistant to chemicals and moisture and flexible enough to squeeze. Won’t stiffen or become brittle from cold; resistant to chipping, crushing and peeling, but will not last with abrasive cleaning or sterilizing.
Copolymer-the process of combining two plastics-such as polyethylene or polypropylene-into a heavy duty plastic used in trash and garbage cans. Polypropylene-in some formulations is among the strongest plastics available. Rigid, lustrous, heat-resistant and boil-proof.
Expanded Styrene-lightweight foam material used for all-plastic picnic jugs, ice chest, etc. Good insulator. Can be punctured; when too light or thin is subject to fairly easy breakage. Polystyrene-rigid or semi-rigid thermoplastic with satiny smooth or textured finish. Shatterproof; resists most foods, drinks, household acids and oils. Burns if subjected to direct flame. Can be used for containers, molded products and sheet material. Occasional contact with boiling water won’t hurt it, but repeated immersions are not recommended. Unlimited range of transparent, translucent and opaque colors.
High-Density Polyethylene-high resistance to heat; is slightly translucent and more rigid than ordinary polyethylene. Resists sub-zero freezer temperatures without cracking or becoming brittle, Dishwasher safe. Thermoset Polyester-rigid plastic used mostly in higher-quality microwave cookware. Withstands heat up to 400 F. Boil-proof and stain-resistant.
High-Impact Polystyrene-much stronger than ordinary polystyrene. Also rigid with lustrous finish. Breakage under normal usage is rare. Urea-heat- and scratch-resistant thermosetting plastic. Not affected by detergents, cleaning fluids, alcohol. Comes in a wide range of colors.
Melamine-thermosetting plastic used mostly in dinnerware and for handles of some kitchen tools. Is mar-resistant and virtually unbreakable. Impervious to detergents, cleaning fluids, alcohol. Dishwasher safe. Vinyl-soft, pliable and resilient thermoplastic that resists stains; won’t peel or become “gummy” like rubber. Abrasive cleaners and direct heat are harmful. Can also be a rigid material.
Nylon-rigid thermoplastic material with glossy surface; almost unbreakable and resist heat and cold. Can be boiled but not scoured. Will ignite if it comes in contact with open flame.

Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.