Water Conditioning & Purification Magazine

The Case for Blowing Your Own PLA Bottles

By Bruce Kucera

The recent introduction of polylactide acid (PLA) into the packaging industry has grabbed the attention of consumers and bottlers alike—and for good reason. PLA is a corn-derived plastic polymer invented by NatureWorksLLC®, a wholly-owned subsidiary of Cargill Inc. (see WC&P September 2005). The food and beverage industry, of which bottled water is a significant part, creates enormous amounts of waste material with its disposable packaging. Simply put, petroleum-based plastics are the backbone of the packaging industry. And PET (polyethylene terephthalate, the most popular petroleum-derived plastic) packaging takes several millennia to decompose. In contrast, PLA bottles, properly processed in a managed, compostable landfill, biodegrade in about 100 days. As an added benefit to the environment, the residue can be recycled as fertilizer for another year’s crop.

As bottled water sales climb dramatically worldwide, the amount of discarded PET bottles dumped into the environment is staggering. According to industry sources, per capita bottled water consumption in the U.S. in 2004 was 25.7 gallons. That amounts to a staggering 165 (20-ounce) bottles per person disposed in 2004. Add to the environmental issues the current economical and political aspects involved with petroleum-based products and you have a host of good reasons why packagers are looking for alternative materials.

No wonder the bottled water industry is looking at PLA! It’s a natural solution in an industry committed to its consumers’ health and well-being.

This article looks at two emerging trends in the bottled water industry: the emergence of PLA bottles as an intelligent alternative to PET bottles; and the growing desire of bottling businesses to cut costs by manufacturing their own bottles on location. How these two trends can come together with PLA-capable blow molders for the bottled water industry will follow.

On-site bottle manufacturing
On-site manufacturing of bottles has advantages. Whether you’re using PET or PLA bottles, the benefits are the same. Why take a do-it-yourself approach? Because it pays!
Manufacturing your own bottles on site can yield a dramatic cost-per-bottle savings, primarily by cutting out the shipping costs. Current petroleum pricing negatively impacts the price of transportation, of course. In some cases, bottlers can save up to 50 percent on their bottles by making their own. Actual savings varies business by business, based on distance from suppliers and other considerations.

On-site manufacturing also helps alleviate inventory problems. When bottlers make their own, they minimize required warehouse space. Additionally, they eliminate concerns about the timing of vendor deliveries. Preform purchase and shipping issues, of course, remain the same.

Blow molders specifically designed for use by small- to medium-sized bottling companies are now available. No longer are the bigger operations the only ones who can benefit from making their own bottles.

PLA bottle making
The technology of PLA, its origins and its general benefits were discussed in detail in WC&P’s coverage last September; you can re-read that article on their website. Here we address the issues involved in designing a blow molder capable of manufacturing bottles from PLA preforms. We also look at the added benefits to the bottlers who use PLA bottles in their businesses.

There is little difference between PLA and PET bottles in terms of appearance and performance. In most cases, what you can do with PET, you can do with PLA, including shape, size, color and other design features. Customers will not know the bottle is made of PLA unless you tell them. The difference is found in material characteristics. Hence, the requirement for PLA-specific blow molders, which must address special issues. Traditional PET blow molders cannot handle PLA successfully.

The primary issue is one of material temperature, which includes both preheating of the preforms before entering the stretch-molding process and subsequent cooling down of blown bottles.

PLA preforms must be heated to 75°C (167°F) before entering the stretch-molding process, as opposed to 100°C for PET. At the higher temperature, PLA starts to shrink, so the typical PET blow molder is problematic with PLA.

While PLA preforms heat up easily, the material is difficult to cool down; bottle deformation results when they are not adequately cooled before they exit the molds. Therefore, the freshly blown bottles must be cooled down quickly before they leave their molds. Consequently, special cooling techniques must be designed and built into each mold.

Additionally, precision process controls over all heating lamps and blowing sequences is a must. Fluctuation of a degree or two either way leads to finished bottle quality issues. PLA’s temperature sensitivity also requires enhanced airflow to ensure even heating in the heat tunnels. When multiple heat tunnels are involved, as is generally the case in blow molders, it is critical to precisely compensate for potentially different heat lamps and airflow so that bottles from each tunnel are consistently heated for optimal performance in the molds. This ensures a consistently high-quality finished bottle.

Precision controls over air pressure and flows are equally critical. This technology helps move PLA material down from the preform’s neck area to the bottom to make sure desired thickness is achieved in the bottle from bottom to top.

Marketing benefits
From a marketing perspective, there are several key advantages for bottlers to convert to PLA bottles.

The first is product differentiation. Let’s face it: there’s not much difference between one bottle of water and another. Brand name, methods of water purification and price are points of differentiation. PLA becomes another point to help bottlers distinguish their product from their competition, particularly from those still using PET bottles.

The bottled water market often targets a demographic that prides itself in healthy lifestyles. Typically, this also includes environmental concern and a proclivity for eco-friendly products. PLA offers a tangible environmentally friendly argument for its use. There’s publicity to be gained and media attention to be earned by announcing a switch to PLA and by promoting the product as using eco-friendly materials.

Following are points about PLA that capture attention of the market, and result in legitimate environmental benefits:

  1. The production process of NatureWorks PLA uses 68 percent less fossil fuel resources than traditional PET plastics. NatureWorks has found that producing 1,000 bottles from PLA resin requires 33 percent less fossil fuel resources and emits 42 percent less greenhouse gases than making 1,000 bottles from PET. (LCA Consultants Report).
  2. PLA is the world’s first greenhouse-gas-neutral polymer.
    Bottlers considering switching from PET preforms to PLA must be aware that preform selection and bottle design are critical to producing high-quality bottles. Make sure your blow molder supplier approves your preform supplier and bottle design for optimal performance.

Final thoughts
Remember, most standard blow molders are not capable of working with PLA. Such blow molders must have special modifications and specialized heating/cooling techniques built in to successfully blow bottles from PLA preforms.

Summary
PLA offers the bottled water industry a tremendous opportunity to make a positive statement about its concern for the health of the environment above and beyond the personal health considerations enjoyed by bottled water consumers. But consumers won’t know they’re using PLA bottles unless they’re told. That provides a strong opportunity to differentiate product from the competition. Combined, growing PLA popularity and the trend toward blowing bottles on site provide strong bottom-line incentives to eliminate the middleman. The combination of the two marketing trends can mean a stronger bottom line for many bottled water operations.

About the author
Bruce Kucera is Vice President of Norland International Inc. of Lincoln, Neb., a company that supplies complete bottled water operations to companies around the world. The company’s products range from turnkey bottling plants to a variety of components for the bottled water industry including distillers, bottle washers, fillers and cappers, blow molders and packaging equipment. Kucera can be reached at (402) 441-3737, (402) 441-3736 (fax) or email: bk@norlandintl.com

About the company
Norland International Inc. is the leading equipment manufacturer for small- to mid-sized bottlers in the United States. The firm is the complete source for bottled water equipment: complete bottled water production lines, water distillation systems and all related equipment such as commercial water distillers, carbon filters, ozone generating systems, bottle washers, fillers and cappers, case-packers and shrink-wrappers and blow molding equipment. In addition, Norland is known worldwide for its industry-leading customer support, including pre-sale consultation and plant design and after-sale service, including installation and maintenance. Contact the company at P.O. Box 67189, Lincoln Neb. 68506 or visit their website, www.norlandintl.com

 

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