Fiberglass is a much older composite than it is thought to be. It was known before the modern production methods. The first known reinforcement which forms the origin of all modern composites is glass fiber.
The Phoenicians, the Egyptians and the Greeks knew how to dissolve the glass into thin fibers. However, it took centuries to turn glass fiber into a commercial product. Until 1930s it was not possible to produce on a large scale. The process that began in the 1930s turned into a large-scale production of continuous fibers that would later be used commercially as structural reinforcements.
Patent applications filed between the years 1933-1937 by the employees of Owens-Illinois Glass Co. (Toledo, Ohio) by Games Slayter, John Thomas and Dale Kleist record important developments that have led to the gradual change in the industry from discontinuous fibrous glass wool production.
4 microns (4 millionth of a meter) of small diameter and thousands of meters in the production of continuous glass filaments in industry and of course in the industry has launched a breakthrough.
These breakthroughs have made the process commercially viable and cost-effective.
The last two patents entitled ğ Textile Material takv and cam Glass Fabric son in the patent series have announced that glass fibers will come as textile reinforcement.The patents were issued in 1938, the same year that Owens-Illinois and Corning Glass Works (Corning, N.Y.) joined Owens-Corning Fiberglass Corp. (OCF). The new company marketed its glass fiber under the Fiberglass brand. It didn't take long for many other manufacturers to enter the market. With numerous processes and product innovations, these manufacturers have contributed to the structural composite reinforcement market of around 4 to 5 million tons per year in the world.
Glass Fiber Production Process
Textile grade glass fibers are made from silica (SiO2) sand melted at 1720 ° C (3128 ° F). SiO2 is also a basic element in quartz, a naturally occurring rock.
However, the structure of quartz is crystalline. So it has a very hard and very regular atomic structure.
And more than 99 percent is SiO2. SiO2 is heated above 1200 ° C (2192 ° F). The medium is then cooled. Thus, SiO2 crystallizes. It becomes quartz.
The glass can be produced by changing the temperature and cooling rates. This changes the quality of the produced glass according to the desired properties.
If pure SiO2 is rapidly cooled when heated to 1720 ° C (3128 ° F), crystallization can be prevented. The production process gives an amorphous or random sequence atomic structure known as glass.
Although continuously refined and improved, today's glass fiber manufacturers follow this high temperature / fast cooling strategy, albeit on a larger scale, in a process almost identical to that developed in the 1930s.
The production process can be divided into five basic stages:
Drying / Packing
Step 1: Batching
An active commercial glass fiber can only be made from silica. However, other components are added to give the operating temperature reduction methods and other features that are useful according to the areas to be used.
For example, E-glass for electrical applications, SiO2, Al2O3 (aluminum oxide or alumina), CaO (calcium oxide or slaked lime) and MgO (magnesium oxide or magnesia) which was developed as a more alkaline resistant alternative to the original soda lime glass with a composition .
Then, E-increasing the difference between the temperatures at which melting of the glass batch and to increase the difference between the temperature at which form a crystalline structure in order to prevent clogging of the nozzle used in this fiberizing, B2O3 (boron oxide) boron was added via
Boron was then added to the E-glass fiber batch via B2O3 (boron oxide). This provided two benefits. This E-glass fiber increases the temperature differences in which the fiberization dissolves and forms a crystalline structure, thereby preventing the blockage of the nozzles.
S-glass fibers developed for higher mechanical strength are based on SiO2, Al2O3, MgO formulation. In applications where tensile strength is the most important feature desired, it contains higher rates of SiO2.
In the first stage of glass production, these materials are carefully weighed and mixed in exact quantities due to their application areas.
In modern manufacturing enterprises, the blending is automated by using computerized weighing units and closed material handling systems.
For example, in a modern production facility, each material is transported to a designated multi-storey storage box (silo) through pneumatic conveyors, capable of holding material from 1.98 to 7.36m³. Just below each compartment there is an automatic weighing and feeding system that transfers the exact amount of each component to a pneumatic mixer.
Step 2: Melting
A further pneumatic conveyor sends the fiber from the batch set to a natural gas-fired furnace at high temperature (ta1400ºC / 2552ºF) to melt the mixture.
These ovens are generally divided into three sections by auxiliary channels to the glass stream. The first part receives the first glass batch, where the melting takes place and the homogeneity of the air bubbles is increased, including the removal of homogeneity.
The molten glass is then transferred to the refinery where the temperature is reduced to 1370 ° C (2500 ° F). The final section of the furnace comprises four to seven shells used for extruding the molten glass to the fibers.
These bakery companies in the world continue in several areas.
The use of larger furnaces increased the annual output from 30,000 to 40,000 mt (66.2 million lb to 88.2 million lb). One of the most important developments has been digital control technology.
The digital controls measure and manage the precise temperature of the glass as the glass moves through the gas and oxygen flow rates in the furnace.
They also provide a softer and more regular flow to the fiberization equipment by blocking other interruptions that may cause interruptions to the formation of bubbles or fibers.
Control of the flow rate of oxygen is very important. Because the furnaces using the latest technology use almost pure oxygen instead of natural air and burn it. This helps natural gas fuel to burn the glass more efficiently and warm.
This reduces the operating costs as less energy is used. A much more green oven technology is also used. Decreases nitrogen oxide (NOx) emissions by 75 percent and carbon dioxide (CO2) emissions by 40 percent.
The oven is difficult to operate. The melting and handling of the glass abrades the bricks covering the inside of the furnace. Glass fiber production is a continuous process that can never be cut. You can't stop after production starts. For this reason, the efforts to extend the service life of the brick is also one of the struggles for the development of kiln technology.
Industry has brought three main approaches to glass melting.
(1) Indirect melt (also called smelting again)
(2) Direct melt using larger-scale furnaces
(3) Direct melt using smaller-scale furnaces, also called paramelites.
For the indirect melt method, the molten glass is cut off. It is rounded, cooled and packed into marbles with a diameter of about 15 mm. They are then transported to a fiber production facility where they are melted for fibermaking. The marbles also facilitate visual inspection of glass for a purer production. This results in a more consistent product.
In the direct melting process, the molten glass in the furnace is directly transferred to the fiber forming mechanism.
Direct melting has become the most common method, as it eliminates the cost of intermediate steps and the cost of re-melting marble.
Step 3: Fibrillation
It includes a combination of glass fiber formation or fiberization, extrusion and attenuation. In extrusion, the molten glass passes through a bushing made of an erosion-resistant platinum / rhodium alloy with very fine holes of 200 to 8,000 in front. Bushing plates are electronically heated and their temperatures are precisely controlled to maintain a constant glass viscosity.
Water jets cool the filaments when they exit the bushing at about 1204 ° C (2200 ° F).
Slimming is the process of mechanically pulling the rolled streams of molten glass into the fibrous elements called filaments.
The diameter of these filaments is one tenth of the human hair. A high-speed winder captures the molten currents and collects by rotating at a peripheral speed of 2 km / 3 km / min. This speed is much faster than the molten glass coming out of the bushes.
Bushes are expensive and the nozzle design is critical for fiber.
The nozzle diameter determines the filament diameter. The amount of nozzle is equal to the number of ends. A 4,000 nozzle bushing can be used to produce a single roving product. The bushings also control the fiber yield or the amount of fiber meter per glass. Zodiac design is also one of the research areas. Specially designed filament diameters improve the performance and contribute to the total production and reduce the cost.
As industry, fiber diameter or micronage range and further specializes in composite reinforcements, production types continue to diversify. Developments in winding have allowed the producers to triple their productivity.
Step 4: Coating
In the final step, a chemical coating or size is applied. Although the terms binder, size and sizing are often used interchangeably in the industry, the size is the correct term for the applied coating and the sizing process is the process used to apply this process. Coatings are generally added at 0.5 to 2.0 percent by weight. Lubricants may include binders and / or coupling agents.
Lubricants help protect the filaments against wear and tear.
The coupling agents are used to improve the resin effluent for a given resin chemistry of the fiber and to strengthen the adhesive bond in the fiber-matrix interface.
Chemicals of some sizes are only polyester resin, and some are only compatible with epoxy. Others can be used with other resins.
Step 5: Drying / Packing
Finally, the drawn, sized filaments are collected in a bundle. These filaments 51 to 1.624 form a glass yarn-wire.
This wire is wound onto a forming drum which is similar to a reel.
After water cooling and sizing, the packages which are still wet are then dried in an oven.
It is then prepared to be palletized, shipped or processed into chopped fibers, rovings or yarns.
The wick is a collection of strands that are not twisted or twisted.
For example, in a multi-end roving package there are 10 to 15 wires wound together. The roving requires additional transport and processing steps.
One Process But One Multi Fiberglass Product
Basic glass fiber processing changed very little after 80 years of commercial production. But there are a lot of improvements on the process.
During the history of fiberglass production, two continuous demands have driven the industry.
First, the desire to increase production efficiency and reduce costs,
The second is the desire to improve the performance characteristics of the finished product.
Polser Inc. We continue to struggle on these two fronts as we continue to pursue new applications to develop our fiberglass reinforced composite products that guide the world.