Improvements Loom In Properties But Not Supplies

The polypropylene supply industry, which says it isn’t getting the pricing it expected, has been forced to reduce resin capacity in some mature geographical markets. Nevertheless, global demand for PP continues to grow. It rose 8.9%/yr from 1990 to 2002, according to Konrad Scheidl of Maack Business Services, Au, Switzerland. But growth is expected to slow to 7.2%/yr by 2005.

In the near term, resin availability may shrink in the coming months, according to Mustafa Al-Sahan, general manager of PP marketing for Sabic, Riyadh, Saudi Arabia. “We are already seeing a lack of propylene feedstock on the market, which is expected to push up prices.” He doesn’t believe that mothballed resin capacity will be reactivated. Instead, producers will concentrate on increasing output of commodity grades at large plants in low-cost feedstock areas. Scheidl forecasts severe PP shortages in Western Europe, North America, and Asia-Pacific by 2005, as well as price hikes.

Contending with higher prices is just one issue processors can expect to face in the next few years. Consultant Patrick Ellis, in Mercurey, France, says processors will be faced with fewer suppliers, greater self-service as resin makers adopt online tools, and fewer business opportunities as labor-intensive jobs go to low-wage countries in Eastern Europe as well as Mexico, China, Indonesia, and Thailand.

Despite a number of technical developments in the pipeline, Robert Genin, president of Basell Polyolefins NV, Brussels, believes high production costs are forcing PP makers to limit R&D to high-value areas such as automotive. Ellis believes many existing commodities R&D programs will run their course.

This will lead to a more limited variety of grades in the future. Jürgen Stebani, managing director of independent research firm polyMaterials AG, Kaufbeuren, Germany, says resin makers want to reduce R&D to cut costs, and will tweak catalyst systems to develop new commodity grades. Basell’s Spherizone technology (Aug 01 MP, 30; MPI, 32) is an example.

Mike Tilston, Danbury, CT-based R&D leader for Dow Chemical, admits a number of the company’s advanced catalyst systems were developed with the aid of external sources. Last year, Procter & Gamble, Cincinnati, OH, and Equistar Chemicals, Houston, TX, agreed to jointly develop a homopolymer PP elastomer for specific consumer packaging and disposable goods applications (Nov 02 MP, 22; MPI, 24).

What else can processors expect in the coming years? Markus Gahleitner, PP senior research specialist for Borealis, Linz, Austria, sees a trend toward optimizing several properties of existing grades. He cites, as an example, the company’s Borpact PP series for thinwalled frozen-food packaging. The company was able to improve the transparency of the high-flow grades, but also impact strength at very low temperatures, which conventional heterophasic block copolymers cannot provide.

Ellis says the next wave of PP developments will include easier-to-process metallocene grades, blends with improved properties, reactor thermoplastic olefins (elastomer-modified PP) as substitutes for plasticized vinyl, nanofilled PP compounds, and improved commodity grades that compete head-on with polyethylene.

A blown film processor in Morocco is finding uses for one such improved commodity grade. The company is using the PP grade to produce hot-fill cement sacks on PE film lines. It is attempting to encroach upon the paper bag market, according to Ellis.

PP has not been compatible with PE blown film equipment because of its longer cooling cycle. Normally, when a PP bubble reaches the collapsing cage, it still has enough heat to cause sticking with the rollers.

PP can be downgaged further than low-density PE while still maintaining its strength. More importantly, it can be used in hot-fill applications unlike PE, which has a lower melt temperature.