Glass wool belongs to a category of glass fiber, is a man-made inorganic fiber. The use of quartz sand, limestone, dolomite and other natural ores as the main raw material, with some soda ash, borax and other chemical raw materials melted into glass. In the melted state, with the help of external force blowing type flocculent fine fibers, fibers and fibers for the three-dimensional intersection, intertwined with each other, showing many small gaps. This gap can be regarded as pore space. Therefore, the glass wool can be regarded as porous materials, with good thermal insulation, acoustic performance.
Glass wool is the molten glass fibrillation, the formation of cotton-like material, the chemical composition of the glass class, is an inorganic fiber . With good molding, low bulk density, thermal conductivity and go, thermal insulation, sound-absorbing properties, corrosion-resistant decorative, stable chemical properties.
The main components of mineral wool stone is blast furnace slag, phosphate slag, fly ash and so on.
Centrifugal glass wool
Centrifugal glass wool internal fiber fluffy interlaced, there are a large number of tiny pores, is a typical porous acoustic materials, has good sound absorption characteristics. Centrifugal glass wool can be made into wall panels, ceilings, space acoustic body, etc., can absorb a large amount of sound energy in the room, reduce reverberation time, reduce indoor noise.
Centrifugal glass wool sound-absorbing properties are not only related to the thickness and weight, but also with the cover material, structure and other factors. In the building application also need to take into account the cost, beauty, fire, moisture, dust, aging resistance and other aspects of the problem.
Centrifugal glass wool belongs to the porous acoustic material, has good acoustic performance. Centrifugal glass wool can absorb sound not because of the surface roughness, but because there are a large number of internal and external connectivity of the tiny pores and holes. When the sound wave incident to the centrifugal glass wool, the sound wave can follow the pore into the material inside, caused by the air molecules in the gap vibration. Due to the viscous resistance of the air and air molecules and the friction of the pore wall, the sound energy is converted into heat energy and loss.
Centrifugal glass wool has good sound absorption performance for sound in high frequency. The main factors affecting the acoustic performance of centrifugal glass wool are thickness, density and air flow resistance. Density is the weight of the material per cubic meter. Air flow resistance is the unit thickness of the material on both sides of the air pressure and air flow rate ratio. Air flow resistance is the most important factor affecting the acoustic performance of centrifugal glass wool. Flow resistance is too small, indicating that the material is sparse, air vibration is easy to pass through, acoustic performance decline; flow resistance is too large, indicating that the material is dense, air vibration is difficult to penetrate, acoustic performance also declined. For centrifugal glass wool, acoustic performance, there is an optimal flow resistance. In practical engineering, the determination of air flow resistance is more difficult, but can be roughly estimated and controlled by the thickness and weight. 1, with the thickness increases, the low-frequency sound absorption coefficient increased significantly, but not much change in high-frequency (high-frequency absorption is always larger). 2, the thickness of the same, the weight increases, low-frequency absorption coefficient also increased;
However, when the weight increases to a certain extent, the material becomes dense, the flow resistance is greater than the optimal flow resistance, the sound absorption coefficient instead of decreasing. For the thickness of more than 5cm weight of 16Kg/m3 centrifugal glass wool, low-frequency 125Hz is about 0.2, in the high-frequency (> 500Hz) sound absorption coefficient has been close to 1. When the thickness of 5cm continue to increase, the low-frequency absorption coefficient gradually increased, when the thickness is greater than 1m above, low-frequency 125Hz absorption coefficient will be close to 1. When the thickness is unchanged, the capacity to increase the low-frequency absorption coefficient of centrifugal glass wool will continue to improve, when the capacity to close to 110kg/m3 acoustic performance to reach its maximum value, 50mm thick, the frequency of 125Hz at close to 0.6-0.7. 0.7. When the weight capacity exceeds 120kg/m3, the acoustic performance decreases, because the material becomes dense, the medium and high frequency acoustic performance is greatly affected, when the weight capacity exceeds 300kg/m3, the acoustic performance decreases a lot. Building acoustics commonly used in the acoustic glass wool thickness of 2.5cm, 5cm, 10cm, capacity of 16, 24, 32, 48, 80, 96, 112kg/m3. 5cm thick, 12-48kg/m3 centrifugal glass wool is usually used.
Centrifugal glass wool acoustic performance also has a close relationship with the installation conditions. When the glass wool board behind the air layer, and the same thickness of glass wool board without air layer of similar sound absorption. Especially in the low-frequency sound-absorbing performance than the material affixed to the hard substrate will have a greater increase in sound absorption coefficient will increase with the thickness of the air layer, but increased to a certain value after the effect is not obvious.
The use of different weight of glass wool and stacked together, the formation of the weight gradually increased in the form of sound absorption effect can be greater. For example, a layer of 2.5cm thick 24kg/m3 cotton board and a layer of 2.5cm thick 32kg/m3 cotton board stacked together the sound absorption effect is better than a layer of 5cm thick 32kg/m3 cotton board. The 24kg/m3 glass wool board made of 1m long section for the triangular tip of the split, the material surface density gradually increases, the average sound absorption coefficient can be close to 1.
Centrifugal glass wool in the building use, the surface is often attached to a certain role in sound transmission of the finish, such as less than 0.5mm of plastic film, metal mesh, window screen, fireproof cloth, glass cloth, etc., basically can maintain the original acoustic properties. Centrifugal glass wool has fireproof, heat preservation, easy to cut and other excellent characteristics, is one of the most commonly used materials for acoustic construction. However, due to the centrifugal glass wool surface non-decorative, and there will be fiber spills, so it must be made into a variety of sound-absorbing components hidden use. The most commonly used is also the most inexpensive structure is the perforated gypsum board ceiling or made of centrifugal glass wool filled with perforated panels wall, perforation rate of more than 20%, basically able to fully play out the centrifugal glass wool acoustic performance. In order to prevent the glass wool fiber spilling, need to be attached to the perforated board behind a layer of non-woven fabric, mulberry paper and other acoustic fabrics, or the use of glass cloth, plastic film, etc. wrapped glass wool. Similar panels with perforated paper-faced gypsum board also have perforated metal panels (such as aluminum), perforated wood panels, perforated fiber cement board, perforated mineral wool panels and so on.
Glass wool panels can be made into acoustic ceiling panels or acoustic wall panels after treatment. Generally common will be 80-120kg/m3 of glass wool board peripheral by glue curing treatment after the outer package of fireproof sound-permeable fabric to form both beautiful and easy to install acoustic wall panels, the common size of 1.2m × 1.2m, 1.2m × 0.6m, 0.6m × 0.6m, the thickness of 2.5cm or 5cm. there are also in the surface of the 110Kg / m3 of glass wool directly sprayed on the surface of acoustic decorative There are also acoustic ceiling panels formed by spraying sound-permeable decorative materials directly on the surface of 110Kg/m3 glass wool. Whether it is glass wool acoustic wall panels or acoustic ceiling panels, need to use a high capacity of glass wool, and after a certain degree of reinforcement to prevent the deformation of the plate or too flimsy. This category of building materials both good decorative and retain the centrifugal glass wool good acoustic properties, noise reduction coefficient NRC can generally reach more than 0.85.
In gymnasiums, workshops and other large spaces, in order to absorb noise, often using centrifugal glass wool as the main sound-absorbing materials of the acoustic body. Acoustic body can be made according to the requirements of the plate, column, cone or other shaped body. The interior of the acoustic absorber is filled with centrifugal glass wool, and the surface is wrapped with an acoustically transparent surface layer. Due to the multiple surfaces of the absorber, the sound absorption efficiency is very high.
In road noise barriers, acoustic measures are required on the side facing the vehicle in order to prevent noise reflection, and barrier panels with centrifugal glass wool as the filler material and a perforated metal plate as the surface layer are often used as well. In order to prevent the glass wool from absorbing water and moisture outdoors, it is sometimes wrapped in PVC or plastic film.
