2011年7月5日星期二

Which plastic bottle safe to use?

If you recycle you’ve probably turned over a plastic container to read the number on the bottom, the one surrounded by the little recycling symbol. Many recycling programs depend on these numbers to tell you which plastics you can and can’t recycle.
Do you know what these numbers mean? Did you know these numbers tell you which plastics are considered safe and not? You may recall there was a big scare recently over BPA plastic leaching chemicals into water bottles and baby feeding bottles, after studies showed that BPA mimics estrogen and interferes with hormone levels.
Plastic Identification Code Type of plastic polymer Properties Common Packaging Applications
Plastic-recyc-01.svg Polyethylene terephthalate (PET, PETE) Clarity, strength, toughness, barrier to gas and moisture. Soft drink, water and salad dressing bottles; peanut butter and jam jars
Plastic-recyc-02.svg High-density polyethylene (HDPE) Stiffness, strength, toughness, resistance to moisture, permeability to gas. Water pipes, hula hoop rings, five gallon buckets, milk, juice and water bottles; the occasional shampoo / toiletry bottle
Plastic-recyc-03.svg Polyvinyl chloride (PVC) Versatility, ease of blending, strength, toughness. Blister packaging for non-food items; cling films for non-food use. Not used for food packaging as the plasticisers needed to make natively rigid PVC flexible are usually toxic. Non-packaging uses are electrical cable insulation; rigid piping; vinyl records.
Plastic-recyc-04.svg Low-density polyethylene (LDPE) Ease of processing, strength, toughness, flexibility, ease of sealing, barrier to moisture. Frozen food bags; squeezable bottles, e.g. honey, mustard; cling films; flexible container lids.
Plastic-recyc-05.svg Polypropylene (PP) Strength, toughness, resistance to heat, chemicals, grease and oil, versatile, barrier to moisture. Reusable microwaveable ware; kitchenware; yogurt containers; margarine tubs; microwaveable disposable take-away containers; disposable cups; plates.
Plastic-recyc-06.svg Polystyrene (PS) Versatility, clarity, easily formed Egg cartons; packing peanuts; disposable cups, plates, trays and cutlery; disposable take-away containers;
Plastic-recyc-07.svg Other (often polycarbonate or ABS) Dependent on polymers or combination of polymers Beverage bottles; baby milk bottles. Non-packaging uses for polycarbonate: compact discs; “unbreakable” glazing; electronic apparatus housings; lenses including sunglasses, prescription glasses, automotive headlamps, riot shields, instrument panels;

1. Polyethylene terephthalate (PET or PETE)
Polyethylene terephthalate (PET or PETE) is one of the most common types of plastic and is commonly found in bottles of soda, juice, water and cough syrup and jars of peanut butter. The bottoms of these containers are usually stamped with the chasing arrows symbol and the number 1, the code for PET.


2. High-density polyethylene (HDPE)
High-density polyethylene, or No. 2 HDPE, is used in shampoo and detergent bottles, milk jugs, cosmetics, motor oil, toys and sturdy shopping bags, and is considered one of the safer plastics. HDPE is often opaque or cloudy. Some recycling centres can only handle clear No. 2 plastics, such as milk jugs, but not colored bottles. As rule of thumb, bottles, jars, and jugs are most likely to be collected for recycling, particularly those labelled 1 or 2. Tubs, lids, spray pumps, buckets, films, bags and items containing toxic chemicals such as drain cleaner, are less likely to be accepted by recyclers.

3. Polyvinyl chloride (PVC)
Polyvinyl chloride, or No. 3 PVC, is found in shower curtains, meat and cheese wrappers, ring binders, some bottles, plumbing pipes and building materials. Commonly called vinyl, PVC and closely related PVDC differ from other vinyls, which lack the toxic chloride. PVC continues to be used in many toys.

4. Low-density polyethylene (LDPE)
Low-density polyethylene, or No. 4 LDPE, is used in shopping bags, six-pack rings, hard drive casings, CD and DVD cases and some bottles. Unlike PVC, LDPE isn’t regarded as a ‘bad’ plastic by most eco watchdogs. Potentially toxic industrial chemicals involved in its manufacture, however, include butane, benzene and vinyl acetate.

5. Polypropylene (PP)
Polypropylene, or PP, is used in the products in this photograph as well as in nappies, pails, dishes, candy containers and lab equipment. The purple product pictured here is made from recycled polypropylene from Recycline. Makers of electronics packaging, including Microsoft, are increasingly using the recycled material instead of toxic PVC.

6. Polystyrene, or Styrofoam
Polystyrene, also known as Styrofoam, is used in disposable cups and take-out food containers, packing peanuts, trays and egg cartons. Most fast-food chains, including McDonald’s, phased out polystyrene for sandwich containers more than 20 years ago. Ozone layer-depleting CFCs haven’t been used to make Polystyrene since the late 1980s.

7. ‘Wild card’
The No. 7 SPI code is generally a wild card marking plastics that don’t fall within the other six categories. These include polycarbonate bottles, which are understood by scientists to wreak havoc on human hormones by leaching bisphenol-A into hot beverages. As a result, polycarbonate baby bottles are losing favour with the public, and retailers including Toys ‘R Us are starting to sell more BPA-free bottles.

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