聚乙烯（Polyethylene）是五大合成树脂之一，是我国合成树脂中产能最大、进口量最多的品种。目前，我国已是世界上最大的聚乙烯进口国和第二大消费国。聚乙烯是由乙烯单体聚合而成，聚乙烯塑料是以聚乙烯树脂为基材，添加少量抗氧化剂、滑爽剂等助剂后制成的塑料产品。
虽然聚乙烯的品种繁多，但是聚乙烯主要的市场还是高密度聚乙烯和低密度聚乙烯。高密度聚乙烯，英文名称为“High Density Polyethylene”，简称为“HDPE”。HDPE是一种由乙烯共聚生成的热塑性聚烯烃。低密度聚乙烯，英文名称为“Low Density Polyethylene”，简称为“LDPE”。LDPE是用聚合级的乙烯用氧或过氧化物为引发剂，在高温高压下进行游离基聚合而制得的。因此低密度聚乙烯又称为高压聚乙烯。
本期我们就来看看这两种常用的聚乙烯在特性及使用上有什么区别吧。
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So all plasticsare the same. Plastic is plastic. Right? Wrong. That’s like saying skim milkand whipping cream are the same. Honestly. Of the seven different plastictypes, HDPE is marked with a 2. HDPE is short for high-density polyethylene. Ofthe seven different plastic types, LDPE is marked with a 4. Guess what LDPE andMDPE stand for? Yep. Low and medium. I am going to show you the differencebetween high, medium, and low density polyethylene with a basic squeeze-metest. See? HDPE, is not very squeezable. MDPE is medium squeezy. And LDPE isthe squeeziest of all. HDPE can be pigmented or unpigmented. That meansit comes in different colors. Uncolored HDPE is translucent, or “naturale” aswe call it in the biz, and is well suited for products with a short shelf life.Like milk. All natural milk in all-natural HDPE. Not only does it look good …taste good, but does a body good too. Inside and out. HDPE has an excellentresistance to most solvents, which makes it the go-to plastic type for detergents,cleaners, industrial chemicals, antifreeze and bleach. It’s also usedextensively for less harsh products like shampoo, conditioner, motor oil andsoaps. Container and Packaging Supply has a huge line of HDPE products. HDPE isused in a lot of different products. Your breakfast of champions comes in acereal box with an HDPE liner. You push your groceries around in an HDPEshopping cart. A lot of the items on the shelves come in HDPE. You may bringyour groceries home in an HDPE grocery bag. HDPE makes grocery shoppingpossible. Recycled HDPE is used to make pipe, buckets (hint,hint), flowerpots,plastic lumber for your deck, and recycling bins. Cool, huh? You can put yourrecyclable containers you want to recycle in a recycled recycling bin. That, myfriends, is the triangle of life. LDPE is squeezy, but also incredibly flexibleand tough almost to the point of being unbreakable. LDPE holds its own shape, that’s why it’s ideal forproducts that need a good squeeze. Container & Packaging Supply has a large selection ofLDPE containers. You can use LDPE containersfor sauces, lotions, creams, spreads, honey, eye drops, contact lens solution, shampoos and conditioners. It can also be translucent (or natural as we call it in thebiz), colored and opaque. LDPE is used in alot of different kinds of common household products. Bags for bread, dry cleaning, fresh produce, and trash cansare made of LDPE. It can also be used as acoating for paper milk cartons and some hot/cold beverage cups. Shipping envelopes and outdoor lumber are also made ofLDPE. LDPE, MDPE and HDPE are all polyethylenewhich is the most widely used plastic. Low,medium and high-density polyethylene are commonly recycled in most communities.
