What is Direct Roving?
Direct roving is a cylindrical product which multiple glass strands combined (one glass strand contains 100 to 200 glass filaments with binders). Some surface treatment is treated depending on the application or molding method.
It is used mainly for FRP related products. Spec of the direct roving differs depending on the purpose of use such as Filament Winding, Pultrusion, BMC, SMC or weaving.
The example of final products are water tank, car and bath tub. It is also used in the building material industry such as building of the factory.
What is composition of the glass?
There are multiple compositions of general glass products. Main composition of fiberglass is generally E glass (“Electric Glass”). E glass contains around 53-56% SiO2. Its strength is heat and insulation resistance. The softening point of E-glass is around 850℃. The heat-resistance temperature of glass roving is said to be around 160℃.
| E glass | C glass | S glass | D glass | |
| SiO2 | 55 | 65 | 65 | 70 |
| Al2O3 | 10-15 | 5 | 25 | 1 |
| CaO | 20 | 15 | – | 1 |
| Mgo | ~2 | ~3 | 10 | – |
What kind of spec？
Roving spec is determined mainly by two elements; glass filament diameter (unit: µm) and gram per 1,000㎡ (“TEX”). Spec differs depending on the manufactures. General specs of diameter are for example 13-20 µm and of TEX are such as 1200, 2400, 4800. If you are looking for fiber glass for weaving, thinner such 4-9µm are recommended.
Compatibility with resin also controls the spec of the roving for example unsaturated polyester resin (UP), vinyl ester resin (VE), or epoxy resin (EP).
How do the different spec of the direct roving been manufactured?
Glass fibers are generally manufactured by passing the melted-liquid glass (at about 1600℃) through countless 1,000 to 4,000 holes in a bushing, and winding them up. More than 100 of those threads are bundled together, and about 10 or more of those bundled threads becomes roving.
The material of the bushing is special alloys (mainly 90% platinum and other rhodium based alloys) because the 1600℃ heated liquid glass passes. The unit price is said to be about 20 million baht/piece. More surprisingly, the life of the bushing is about 1 year (depending on production volume).
What countries manufacture the direct roving? Looking for made-in-Thailand?
China is the largest roving supplier in Asia. The largest manufacture is said to have capacity of 10 million tons per year. They have a huge kiln.
In recent years, however, because of this uncertain global situation, the movement of “China Plus One” is going forward all over the world. As a result, the roving made outside China are attracting more attention, mainly from Japanese and Taiwanese companies.
Maeda Enterprise Thailand sells rovings made in Thailand. Please feel free to contact for samples, quotation or more information.
