What looks like a paper container, is formed like a paper container but is not a paper container?
New, patented technology from Paper Machinery Corp. is trying to answer that question with plastic. The Milwaukee-based company, calling itself the world's largest source of forming machines for paperboard packaging, wants to become a world leader in the forming of plastic containers.
The company, working with sheet extruder Spartech Corp. and others, has developed a proprietary process called Barrier Plus to make moisture-resistant, two-piece plastic containers that have the look and feel of paper. The company launched two container forming machines at Pack Expo International, held Nov. 7-11 in Chicago, and plans a large rollout of the faux-paper packaging product.
The containers are made on what looks like a conventional paper-container forming machine, using a polypropylene blend on a flat sheet that is pre-printed.
Packaging companies now making injection molded or thermoformed cups might want to take note. The new process is gunning for some of that business, as well as that from paper cup manufacturers.
Under traditional methods, PP sheet cannot be printed easily in advance, said Cary Kalal, PMC international sales manager. It has to be printed in a secondary process after a container is made, or a label added to the product. In many cases, the paper container itself is coated with PP to form a sturdier barrier material, according to Kalal.
Spartech engineers worked on a new PP blend that allows graphics to be printed in advance on the flat sheet. PMC outfitted its forming machines with tools consisting of special alloys, and it modified its heating system to seal the material.
The end result: a machine that takes two sheets of printed PP, forms them into side walls and a base and then seals the parts together and tucks and rolls the rim. The process is similar to that used to form paper containers, Kalal said.
``It has the richness in graphics of a paper container that you previously could not get in plastic,'' he said. ``For shorter runs, it's a good, low-cost alternative to either injection molding or thermoforming.''
Tooling costs are lowered dramatically by using a forming machine, Kalal said. The containers mark a major improvement in graphics, he said. There is no worry of a label wrinkling or collapsing, he said.
The company has installed its first machine, used to make flower pots filled with seeds used in the garden and nursery market. The buyer, Productivity California Inc., or ProCal for short, is making PP containers at its South Gate, Calif., headquarters, Kalal said.
ProCal received the first PMC plastic forming machine in April, a test program for the new equipment. The pots are being distributed at Home Depot stores and other locations, he said.
Several other PMC machines are on order in North America, and the company is taking a look at the global market, he said. The larger of the two PMC machines can make 225 containers per minute, while the smaller version, which can make 115 containers per minute, will start shipping next summer.
The machines cost, on average, about $300,000, putting them in the price range for molding or thermoforming equipment. The steel tools for the forming presses cost about $80,000, he added.
The new process joins a cottage industry for plastic containers. Both thin-gauge thermoformers and injection molders have enlisted in a growing conversion to plastics from paper, both in cups and containers. But modifying the PP has enabled processing to become more like that for pre-printed paper, said Gerald Meier, PMC vice president of packaging.
``Modifying the PP material was necesssary for what has tradtionally been achievable on PMC machinery with PP-coated paperboard,'' Meier said in a news release. ``This is truly a technological breakthrough with clear advantages over paperboard as well as thermoforming or injection molding of plastics.''
The process is especially suited for those products that need moisture barriers, such as cookies, cereal, nuts, fruit snacks or even ice cream, added Spartech market manager Jonathan Cage. Spartech spent two years modifying its PP sheet to create the printed blanks that move through the forming machine, Cage said.
``These are for applications that have been far more challenging in the past for plastics,'' Cage said. ``There's a market for products that need moisture protection or extended shelf life from what paper can give.''
PMC also worked with several printers and converters, including paper maker Smurfit Stone Container Co., but is not wedded to one company, according to Kalal. And while Spartech provided the initial development in coming up with a formable PP sheet, other extruders may be added, especially if a customer requests a different company, he said.
``The sheet can be made by many companies,'' he said. ``The difference is in the forming technology.''
PMC officials did not reveal too much about how the machinery differs, except to say that the machines include a unique heating system to bond the two sheets of plastic.
The company, working from a 125,000-square-foot plant in Milwaukee, has installed more than 1,500 paper-forming machines in more than 45 countries.