Global glass-fibre production: changes across the board

The continuous-glass-fibre segment (continuous-filament glass fibre/reinforcement glass fibre) accounts for a good part of business in the overall glass sector, in terms of tonnage and (especially) value. Other product categories include container glass (packaging), flat glass (automotive/building), domestic glass (tableware, etc.), and special glass (lighting/electronics, etc.).

Over the years, glass-fibre producers have been developing new products by optimizing their production processes, glass compositions, and sizings (interface with the matrix). As a consequence, a broad range of products is now available on the market, although they will not perform in the same way.

Glass composition is one of the key parameters leading to higher-strength fibre, but not the only one. Filament collection, alignment, sizing formulations and sizing application are a few of the many production parameters that also play a key role in final strand properties. Sizing is designed mainly as a function of the process used (e.g. pultrusion, filament winding, weaving or chopped strand) and of resin compatibility (thermoset or thermoplastic).

E / ECR / Advantex / highperformance glass fibre

Glass fibre is generally classified into four large families, which are E, ECR, Advantex and HP. Pioneer Owens Corning started producing E-glass in 1938, S2-glass in 1968, ECR-glass in 1980, Advantex in 1997, and high-performance (HP) glass fibres in 2007. E-glass, which is the reference, is composed of 53-60% SiO2, 20-24% earth alkali oxides, 5-10% B2O3, 5-10% Al203 plus other minor components. For environmental reasons, the trend is to reduce the B2O3 content as much as possible.

Corrosion-resistant ECR-glass is reserved for applications in which resistance to chemicals (either acid or base) is critical, e.g. all types of storage.

Advantex glass has been formulated as boron-free E-glass. In addition to its improved ecological profile (lower environmental footprint), Advantex also provides significantly improved mechanical and corrosion resistance properties over standard E-glass. According to ASTM D578 and ISO 2078, Advantex is both an E-CR glass and E-glass type.

High-performance glass reinforcements (HP) are made from a new patent-pending glass formulation that is not only a boronfree glass type just like Advantex glass reinforcements, but is specifically designed to offer superior static and dynamic mechanical properties (strength, stiffness, strain, fatigue), and significantly higher thermal and corrosion resistance properties than all traditional types of E-glass.

Glass fibre: yarn versus roving

The tex unit (or yield) expresses the roving or yarn fibre’s weight in grams per thousand metres, and is currently used to specify the glass-fibre type. Filament diameter (microns) is used to a lesser extent. We need to make a distinction between the two types of glass fibre, since the producers and applications differ:

Yarn refers to strands under 300 tex with filaments 5-9 microns in diameter. This is called “textile” yarn for weaving on fast airjet or rapier looms for Printed Circuit Board (PCB) electronic or flexible reinforcement (Teflon, PVC, silicon, or paper) applications mostly. To facilitate weaving them into fabrics, most of these yarns have textile sizing, which must be eliminated (heatcleaning) and replaced by a coupling agent that is compatible with the resin being used. Mainly E-glass is used, although new types of glass are emerging, such as AGY’s L-Glass and Nippon Electric Glass Co., Ltd.’s T/NE.

Roving refers to strands from 300-4000+ tex with filaments 10-24+ microns in diameter. The sizing must be chosen as a function of the type of processing and resin used. Roving is available in the form of direct roving, assembled roving, continuous filament mat and chopped strand. For “mechanical” applications like wind energy, aerospace, recreation and boat building, companies like 3B (HiPer-Tex), OC (Xstrand), Sinoma (HS2 and HS4), CPIC, and Jushi are going for high performance.

Global glass-fibre production capacity (yarn and roving)

It is difficult to have an exact idea of the global production capacity for glass fibre because producers are reluctant to disclose their capacity, as expressed in the number of furnaces and the furnace capacities. Over the past three years, these producers have had to shut down some of their furnaces temporarily to adapt to the volatile market demand. The 2008/2009 economic crisis also led to the postponement of a number of investment projects. We have listed main roving and yarn producers in the two tables below, by region of production. Only five of them show up in both tables, indicating a degree of specialization both in production and in the applications.

Conclusion

Yarn producers account for 900,000 metric tons of production. Yarn production is highest in Asia, with 65- 70%. North America comes next with 20-25%, then Europe, where yarn production is declining, with 5-10%. Production is lowest in Japan, with 3- 8%. Roving producers account for roughly 3,800,000 metric tons of production. Roving production is showing a sharp increase in Asia (including continental China) with 55-60%. Europe comes next with 20- 25%, then North America with 15- 20%. Japan, India, Korea, and Hong- Kong have very low levels of production, only 5% lumped together. Heavy demand from the Asian domestic markets is expected over the coming years, leading to a flurry of investment an-nouncements all over Asia (including continental China).

Considering the current product mix and market needs, it is estimated that 70-80% of this installed capacity will be used in 2010. The future for glassfibre- reinforced composites is looking rosy!