A latest Article about BOPP

Demand for biaxially oriented polypropylene (BOPP) has grown 3.5% per annum over the last five years (to the end of 2019). The industry is worth around US$14 billion, supplying around 8.3 million tonnes last year. But what effect has a year of unprecedented change had on the outlook for BOPP?

This article draws on findings from our latest BOPP Film Global Supply Demand Report.

Slower demand in China had slowed global growth at the start of 2020

Chinese BOPP film demand has been unable to match the pace of new capacity added in China in recent years. Additional capacity has meant increased competition, excess product in the market and rising inventories.

Film demand growth slowed steeply in 2019, with some sources even reporting a slight decline in consumption. In the first half of last year, there was a noticeable reduction in operating rates – an apparent attempt to balance a well-oversupplied market.

As the world’s largest BOPP film market (accounting for almost half of global demand), China’s slowing demand growth has resulted in a slower global growth rate overall, in the last five years to the end of 2019.

About BOPP Films...

 

Biaxially Oriented Film -

Biaxially oriented polypropylene (BOPP) film is film stretched in both machine and transverse directions, producing molecular chain orientation in two directions. BOPP film is produced by a tubular process, in which a tubular bubble is inflated, or a tenter frame process, in which a thick extruded sheet is heated to its softening point (not to the melting point) and is mechanically stretched by 300–400%. Stretching in the tenter frame process is usually 4.5:1 in the machine direction and 8.0:1 in the transverse direction, although these ratios are fully adjustable. It is a widely used process, more common than the tubular process, and a glossy, transparent film is produced. Biaxial orientation results in increased toughness, increased stiffness, enhanced clarity, improved oil and grease resistance, and enhanced barrier properties to water vapor and oxygen. Impact resistance, low-temperature impact resistance, and flexcrack resistance are substantially modified. BOPP films are used in food packaging and are replacing cellophane in applications such as snack and tobacco packaging due to favorable properties and low cost (Fortilene Polypropylene Properties, Processing, and Design Manual, 1981; Goddard, 1993).

Oriented films can be used as heat-shrinkable films in shrink-wrap applications or can be heat set to provide dimensional stability. Heat sealing is difficult in BOPP films, but can be made easier by either coating the film after processing with a heat-sealable material (such as polyvinylidene chloride) or by coextrusion with one or more copolymers before processing to produce layers of film. Copolymers used in sealing layers must have high gloss and clarity and should have low sealing temperatures to prevent distortion of the oriented polymer during sealing. Random copolymers containing 3–7% ethylene are often used as sealing layers; the lower melting point (<132°C; <270°F) results in a 30% increase in line speeds, and they can be recycled with no significant loss of strength or clarity. Coating or coextrusion increases the barrier properties of BOPP film, decreasing its permeability to gases. Common barrier polymers are ethylene vinyl alcohol, polyvinylidene chloride, and polyamide; five or more layers may be coextruded or laminated, or the barrier polymer can be dispersed in the matrix polymer (Fortilene Polypropylene Properties, Processing, and Design Manual, 1981; Goddard, 1993; Polymers in Contact with Food, 1991).