The market for composites

Composites are one of the major applications for the glass and textile industry.
Breaking down the data available to generate a realistic picture of the current dimensions and possible developments for the future in the textile sector represented by composites is not an easy task.
If we refer to the market survey carried out a few years ago (1995) by D. Rigby & Associates, technical textiles used in composites accounted for 16.0% of the entire technical textile market in terms of weight and 10.3% in terms of value. The trend for the period 1985-2005, taken into consideration by the research project, is extremely positive (+ 9.5% per year) higher than the general trend for technical textiles (+ 6.3% per year) (Tables 1, 2).

Another item of global data regards the quality of the fibers used for reinforcement: in composites it is almost always glass.
In 1995 carbon fibers (Tables 7, 8) accounted for only 0.6% by weight, and aramidic fibers 0.3%. It is interesting to note that in the period 1985-2000 the amount of fiberglass used increased (+ 204%) and even though the other two fibers increased by a much greater percentage (carbon fibers + 385% and aramidic fibers + 353%) they remained marginal in terms of quantity.
It should also be noted that carbon fibers have an average cost of $55.00 per kg, as opposed to $1.80-$1.90 per kg for fiberglass, i.e. about 30 times as much as fiberglass. Aramidic fibers cost about $30.00, 16 times as much as fiberglass.
In terms of density, however, aramidic fibers are advantageous in this respect (1.4-1.45 g/cu.cm.), and even carbon fibers (1.7-1.9 g/cu.cm.) have a lower density than fiberglass (2.4-2.6 g/cu.cm.).
In 1995, a total of 2,300,000 tons of fiberglass were consumed, at a cost of $4.3 billion. 1,500,000 tons ($2.9 billion) were used for reinforcement in FRP. Only 9,000 tons of carbon fibers were used, for a total of $500,000,000.
In the U.S., reinforced plastic in 1998 amounted to 1,635,000 tons; the fiberglass employed in this field amounted to 453,000 tons, or 27.7%.

Fiberglass is used in one of two ways:

• for thermal and acoustic insulation (glass wool);
• for mechanical reinforcement

The latter of these two uses represents about 35% of the total but is growing faster with respect to the former (3% per year as against 2%).
Also in the U.S., in 1987 reinforced thermoplastics made up 26.4% of the total, while thermosetting materials accounted for 74.6%; in 1996 the percentages were 36.8% and 63.2% respectively; in 2001 they are expected to reach 38% and 62%.

The applications of composites in Europe, USA and Asia are shown in Tables 3, 4, 5.

Table 3. Distribution of the applications for composites in Europe

Applications	%
Trasportation	33
Construction and public works	31
Industry and agriculture	14
Shipbuilding and consumer goods	10
Electricity and electronics	8
Other applications	4

Table 4. Distribution of the applications for composites in the U.S.

Applications	%
Trasportation	32
Construction and public works	30
Industry and agriculture	18
Shipbuilding and consumer goods	9
Electricity and electronics	7
Other applications	4

Table 5. Distribution of the applications for composites in Asia

Applications	%
Trasportation	17
Construction and public works	30
Industry and agriculture	8
Shipbuilding and consumer goods	11
Electricity and electronics	32
Other applications	2

In Europe, the composites used in construction include the specific applications shown in Table 6 :

Table 6. Applications for composites used in construction in Europe

Applications	%
Electricity	23
Roofing	20
Industrial infrastructures	19
Sanitary systems	11
Floor covering	8
Insulation of facades	6
Decorationn, architecture	4
Other applications	9

Glass

The most important fiber at the present time for the production of textile reinforcement for composite materials is glass. It is relatively easy and inexpensive to produce in relation to its high performance features, resistance to heat, chemicals and mechanical stresses. The only drawback to this important fiber is its high density as compared with synthetic fibers that make products lighter. Fiberglass comes in the following forms:

• textile filament, plain or twisted, in various counts
• texturized (high bulk) filament
• rovings
• reinforced rovings
• pre-impregnated rovings
• cut thread (3-12 mm) for reinforcing thermoplastic or thermosetting resins
• chopped fibers (0.1-0.2 mm) for reinforcing thermoplastic resins and polyurethane
• pads of fibers (50 mm) held together by binders
• pads of continuous filaments held together by binders
• needled felts with 50 mm fibers

Glass is now used in 95% of cases to reinforce both thermoplastic and thermosetting composites; thermoplastics have good resistance to impact on their own account, and in combination with fiberglass it is possible to achieve good mechanical and heat resistance as well as good dimensional stability.

To some extent fiberglass is the leading fiber on the composite market; the production of fiberglass is concentrated in the hands of a few very large groups that lead innovation and thereby influence the development of technology in the field of composites as a whole: carbon, aramidic and other synthetic fibers are still only used to a limited extent because of their high cost, for highly specialized applications requiring particularly high performance.

Table 7. World sales of carbon fibers for composites

Year	tons	annual growth %	milions $	annual growth %	$/kg
1992	5890	-	374,1	-	63,5
1993	6613	12	384,9	3	58,2
1994	7894	19	461,4	20	58,5
1995	8931	13	464,8	0,7	52,0
1996	9365	5	489,2	5	52,2
1997	11762	26	621,4	27	52,8

Table 8. Characteristics of carbon fibers used in composites

Types of fibers	Modulus GPA	$/kg min.	$/kg max.
Standard (12K)	220 - 240	39,7	44,2
Intermed. modulus (12K)	275 - 345	68,4	72,8
High modulus (12K)	345 - 480	132,5	143,5
Ultra-high modulus (3K, 6K, 12K)	480 - 970	264,9	1986,8
Heavy tow (48-320K)	220 - 240	17,7	24,3

Table 9. Carbon fibers, glass fibers, aramid fibers

Parametro	Carbon PAN	Carbon pitch	Glass E	Glass Ar	Glass S	Aramid
Tensile strength (GPa)	1,8 - 7,0	1,4 - 3,0	3,5	3,5	4,6	2,6 - 3,4
Modulus ( GPa)	230 - 540	140 - 820	73,5	175	86,8	55 - 127
Elongation at break (%)	0,4 - 2,4	0,2 - 1,3	4,8	2,72	5,4	2 - 4,6
Density (g/cm3)	1,75 - 1,95	2,0 - 2,2	2,57	2,68	2,46	1,39 - 1,44