阅读说明：本技术 用疏水剂处理的棉表面和由其制成的隔音板 (Cotton surface treated with hydrophobic agent and acoustical panel made therefrom ) 是由 W·栾 M·布朗 俞清 S·A·博根 C·菲济 于 2018-05-23 设计创作，主要内容包括：一种制备纤维板的方法,所述方法包括用拒水剂对矿棉进行表面处理,得到拒水表面处理的矿棉,将拒水表面处理的矿棉与水掺合,得到浆液,以及使所述浆液脱水和干燥,得到纤维板。还提供一种制备具有用拒水剂处理的表面的矿棉的方法,所述方法包括使拒水剂乳液与矿棉接触和使所述矿棉干燥,以及一种制备拒水表面处理的纤维板的方法,所述纤维板包括具有用拒水剂预处理的表面的矿棉。(A method for producing a fiberboard, the method comprising subjecting mineral wool to surface treatment with a water repellent agent to obtain water-repellent surface-treated mineral wool, blending the water-repellent surface-treated mineral wool with water to obtain a slurry, and dehydrating and drying the slurry to obtain the fiberboard. Also provided are a method of making mineral wool having a surface treated with a water repellent comprising contacting a water repellent emulsion with mineral wool and drying the mineral wool, and a method of making a water repellent surface treated fiberboard comprising mineral wool having a surface pretreated with a water repellent.)

1. A method of making a fiberboard, comprising:

carrying out surface treatment on mineral wool by using a water repellent agent to obtain water-repellent surface-treated mineral wool;

blending the mineral wool subjected to the water repellent surface treatment with water to obtain slurry; and

and dehydrating and drying the slurry to obtain the fiber board.

2. A method of preparing mineral wool having a surface treated with a water repellent agent comprising:

contacting the water repellant emulsion with mineral wool; and

the mineral wool is dried.

3. A fibreboard comprising water repellent surface treated mineral wool having a surface pre-treated with a water repellent agent.

4. The method of claim 1 or 2 or the fiberboard of claim 3, wherein surface treating the mineral wool comprises providing the water repellent in an amount ranging from about 0.01 wt% to about 0.20 wt% by weight of the surface treated mineral wool.

5. The method of claim 1 or 2 or the fiberboard of claim 3, wherein the water repellant comprises at least one of polydimethylsiloxane, polymethylhydrosiloxane, and combinations thereof.

6. The method of claim 2, wherein the contacting comprises spraying a water repellant emulsion solution into a cupola collection chamber.

7. The fiber board of claim 3, wherein the board further comprises starch.

8. The fiberboard of claim 3, wherein the board is characterized by a water holding capacity reduction of about 50lbs/MSF relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent agent, and/or the board is characterized by a water holding capacity reduction of about 100lbs/MSF relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent agent.

9. The fiber board of claim 3, wherein the eNRC value of the board is increased by at least about 0.05 relative to an equivalent fiber board wherein the mineral wool is not surface treated with a water repellant.

10. The fiberboard of claim 3, wherein the board is characterized by an increase in water swelling of about 40% to 50% relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent.

Technical Field

The present disclosure generally relates to cotton surfaces treated with hydrophobic agents. More particularly, the present disclosure relates to a method of surface treating cotton with a water repellent agent, a method of forming an acoustic panel comprising surface treated cotton, and an acoustic panel comprising surface treated cotton.

Background

Acoustical panels (or panels) are specially designed systems that are intended to improve the acoustic effect by absorbing sound and/or reducing sound transmission in indoor spaces (e.g., rooms, corridors, conference halls, etc.). While there are many types of acoustical panels, the various acoustical panels that are commonly found are generally constructed of mineral wool fibers, fillers, colorants, and binders, as disclosed, for example, in U.S. patent No. 1,769,519. These materials, as well as various other materials, can be used to provide acoustical panels having desirable acoustical properties and other properties (e.g., color and appearance).

Fiberboard, such as the basemat and acoustical panels of conventional ceiling tiles, is typically made using a wet forming process. The components that make up the fiberboard (e.g., mineral wool, fillers, colorants, and binders) are mixed in water to form a dispersion and then flowed onto a moving support wire screen (e.g., a support wire screen of a Fourdrinier machine) to form a green board. The green sheet is then dewatered and dried in a heated convection oven to form a lightweight mat of acoustical panel. Drying in a heated convection drying oven is generally the production limiting step and is also the most expensive production step.

The sound insulation performance of the sound insulation sheet is characterized by Noise Reduction Coefficient (NRC) and Ceiling Attenuation Class (CAC) values. NRC is a measure of sound absorption and can be determined according to ASTM C423. The NRC value is the average of four sound absorption coefficients for a particular surface at frequencies of 250Hz, 500Hz, 1000Hz, and 2000Hz, which cover the frequency range of typical human speech. NRC is represented by a number between 0 and 1.00, which represents the fraction of sound reaching the panel that is absorbed. The baffle with an NRC value of 0.60 absorbs 60% of the sound generated by the impact and deflects 40% of the sound. Another test method is estimated NRC ("eNRC"), which uses an impedance tube as described in ASTM C384. The ability to reduce sound propagation is measured by the value of the ceiling attenuation class ("CAC") as described in ASTM E1414. The CAC value is measured in decibels ("dB") and represents the amount of sound reduction as sound propagates through a material. For example, acoustical panels with a CAC of 40 reduce the transmitted sound by 40 decibels. Similarly, the reduction in sound transmission can also be measured by its sound transmission class ("STC") as described in ASTM E413 and E90. For example, a panel with an STC value of 40 reduces the transmitted sound by 40 decibels.

Disclosure of Invention

One aspect of the present disclosure provides a method of making a fiberboard, the method comprising surface-treating mineral wool with a water repellent agent to obtain water-repellent surface-treated mineral wool, blending the water-repellent surface-treated mineral wool with water to obtain a slurry, and dehydrating and drying the slurry to obtain the fiberboard.

Another aspect of the present disclosure provides a method of making mineral wool having a surface treated with a water repellent comprising contacting a water repellent emulsion with mineral wool and drying the mineral wool.

Another aspect of the present disclosure provides a water repellent surface treated fiberboard comprising mineral wool having a surface pretreated with a water repellent agent.

Other aspects and advantages will be apparent to those of ordinary skill in the art from a reading of the following detailed description. While the methods and compositions are susceptible of embodiments in various forms, the following description includes specific embodiments, with the understanding that the present disclosure is illustrative, and is not intended to limit the disclosure to the specific embodiments described herein.

Detailed Description

The present disclosure provides a method for producing a fiberboard, the method comprising surface-treating mineral wool with a water repellent agent to obtain water-repellent surface-treated mineral wool, blending the water-repellent surface-treated mineral wool with water to obtain a slurry, and dehydrating and drying the slurry to obtain the fiberboard. In an embodiment, surface treating the mineral wool comprises providing a water repellent in an amount ranging from about 0.01 wt% to about 0.20 wt% by weight of the mineral wool. In an embodiment, surface treating the mineral wool comprises contacting the water repellent emulsion with the mineral wool and drying the mineral wool. In an embodiment, the water repellant comprises at least one of polydimethylsiloxane, polymethylhydrosiloxane, and a combination thereof.

As used herein, "water repellant" refers to an agent that provides a hydrophobic surface to mineral wool and inhibits wetting of the mineral wool by aqueous or polar solvents.

As used herein, "water repellent surface-treated mineral wool" refers to mineral wool that has been previously treated with a water repellent agent such that the mineral wool includes a water repellent coating adhered to the surface of the mineral wool. The mineral wool of the water repellent surface treated mineral wool may comprise a partially discontinuous coating of water repellent or a substantially continuous coating of water repellent.

The present disclosure further provides a method of making mineral wool having a surface treated with a water repellent comprising contacting a water repellent emulsion with mineral wool and drying the mineral wool. In embodiments, the water repellant is provided on the mineral wool surface in an amount ranging from about 0.01 wt% to about 0.20 wt%, based on the weight of the treated mineral wool. In some embodiments, the contacting comprises spraying the water repellant emulsion into the cupola collection chamber. In an embodiment, the contacting comprises cooling the mineral wool and coating the mineral wool with a water repellent. In some embodiments, the water repellant comprises at least one of polydimethylsiloxane, polymethylhydrosiloxane, and combinations thereof.

The present disclosure further provides a fiberboard comprising water repellent surface-treated mineral wool having a surface pretreated with a water repellent agent. In an embodiment, the fiberboard further comprises starch. In an embodiment, the mineral wool is surface coated with from about 0.01 wt% to about 0.20 wt% of a water repellent, based on the total weight of the treated mineral wool. In an embodiment, the board is characterized by a reduction in water holding capacity of about 50 pounds (lbs)/thousand square feet (MSF) relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent. Optionally, the board is characterized by a reduction in water holding capacity of about 100lbs/MSF relative to an equivalent fiberboard wherein the mineral wool is not surface treated with a water repellent.

As used herein, "equivalent fiberboard" includes modifiers, typically "wherein the mineral wool is not surface treated with a water repellent. "equivalent fiberboard" as used herein means that the composition of the fiberboard is the same as that of the second fiberboard with which the first fiberboard is compared, and/or the method of making the fiberboard is the same as that of the second fiberboard, except for the indicated modification conditions.

In an embodiment, the water repellant comprises at least one of polydimethylsiloxane, polymethylhydrosiloxane, and a combination thereof. In an embodiment, the eNRC value of the panel is increased by at least about 0.05 relative to an equivalent fiberboard wherein the mineral wool is not surface treated with a water repellent. In an embodiment, the board is characterized by comprising cotton fibers having an increase in water swell of about 40% to about 50% relative to the water swell of the cotton fibers of an equivalent fiber board wherein the mineral wool is not surface treated with a water repellent.

Water repellent surface treated mineral wool and fiber boards including the surface treated mineral wool disclosed herein have one or more advantages including providing reduced density and correspondingly improved acoustical properties to the fiber board, providing fiber boards with improved water swell properties, providing fiber boards with improved water retention properties and correspondingly improved drying times, and/or the water repellent can supplement a mineral fiber dusting agent, such as polyethylene glycol, which provides industrial hygiene, but no useful properties to the final fiber board.

Method for producing surface-treated mineral wool

A method of making the water repellent surface treated mineral wool (i.e., mineral wool having a surface treated with a water repellent) of the present disclosure generally includes contacting a water repellent emulsion with mineral wool and drying the mineral wool.

Mineral wool consists of fibres of inorganic raw materials. Mineral wool is a term that is widely used in connection with various related vitreous products. Generally, mineral wool is a glass fiber-like material that is composed of very fine interlaced mineral wool that is somewhat similar in appearance to loose wool. It is composed mainly of calcium and silicates of aluminium, chromium, titanium and zirconium. Typically, mineral wool is made from natural rock or slag. Slag is a term widely used to refer to the waste products of the major metals and foundry industry, including deposits from furnace lining charge impurities, ash from fuel, and fluxes used to clean the furnace and remove impurities. In general, the chemical composition of mineral fibers differs significantly from the chemical composition of glass fibers, although the appearance of mineral fibers is similar to that of glass fibers, due to the higher iron, calcium and magnesium content, and the relatively lower proportion of silica to aluminum.

Conventional techniques for preparing mineral wool are described in U.S. patent No. 2,020,403; 4,720,295 No; and 5,709,728, which are incorporated herein by reference in their entirety. Common cotton manufacturing involves: in a suitable furnace (e.g., a cupola furnace), raw materials (e.g., slag, basalt and/or granite) are melted with coke and in the presence of oxygen, and the composition is heated to a temperature in the range of 1,400 to 2,000 ℃. The process disclosed herein is not limited to a cupola furnace. Other furnaces, such as electric furnaces or submerged combustion melting furnaces, will also function. The materials used in cupola furnaces require specific product sizes to allow proper bed breathing and combustion gas flow. An electric furnace or submerged combustion melting furnace accommodates materials of any size, even down to the size of sand grains. Typical cupola sizes will be 7.5-10cm (3-4 inches)/10-15 cm (4-6 inches). The melt is then spun into cotton in a fiberizing spinner by a continuous gas stream.

The contact of the water repellent emulsion with the mineral wool is not particularly limited. In some embodiments, the mineral wool fibers first prepared, for example, in a cupola furnace are then removed from the cupola furnace, cooled and contacted with a water repellent. The cooled fibers may be contacted with a water repellent by immersing the cotton in a dilute emulsion of the water repellent and then dried in an oven to promote adhesion of the water repellent to the fibers. The cotton may be soaked in the diluted water repellent for a period of time sufficient for the water repellent to adhere to the fibers. For example, the cotton may be soaked in the diluted water repellant emulsion for at least about 10 minutes. Typically, the cotton is dried at a temperature of about 100 ℃ or more, about 150 ℃ or more, about 200 ℃ or more, or about 250 ℃ or more, as long as the drying temperature is below the flash evaporation temperature of the water repellent to avoid burning out. In some embodiments, the contacting is performed after spinning the melt into fibers and before cooling the cotton fibers. For example, the water repellant emulsion may be pumped into the cupola collection chamber through a nozzle that atomizes the emulsion and coats the cotton fibers, thereby simultaneously coating and cooling the fibers. The water repellency concentration of the water repellent emulsion solution for spraying into the collection chamber of the cupola can be in the range of about 2.5 wt% to about 20 wt%, or about 5 wt% to 10 wt%, for example about 2.5 wt%, about 5 wt%, about 7.5 wt%, about 10 wt%, about 12.5 wt%, about 15 wt%, about 17.5 wt%, or about 20 wt%. Generally, if the concentration of the water repellent in the emulsion solution is less than about 2.5%, the swelling characteristics of the resulting cotton are not improved. Furthermore, if the concentration of the water repellent in the emulsion solution is above about 20%, the efficiency of the cotton surface treatment is unacceptably low and the Total Hydrocarbon (THC) emission value of the resulting fiberboard is unacceptably high. The flow rate of the water repellent emulsion through the nozzle may be in the range of from about 5gph to about 40gph, or from about 7.5gph to about 30gph, or from about 10gph to about 25 gph. Generally, the efficiency of cotton surface treatment is unacceptably low when the flow rate is outside the range of about 5 to about 40 gph.

The water repellant may be any water repellant to render the surface treated cotton less wettable by water, thereby providing a fiberboard having fibers that are more independent and better dispersed when contacted with water, such as in an aqueous slurry used to make the fiberboard. Suitable water repellents generally include hydrophobic materials having a flash temperature high enough to avoid burning out at drying temperatures (e.g., at about 150 ℃ or higher or 250 ℃ or higher) and having low emissions even when heated. Examples of water repellents include, but are not limited to, polydimethylsiloxane, polymethylhydrosiloxane, and combinations thereof.

Water-repelling agents in the range of about 0.01 wt% to about 1.00 wt%, for example about 0.01 wt% to about 0.25 wt%, or about 0.01 wt% to about 0.20 wt%, or about 0.02 wt% to about 0.1 wt%, or about 0.03 wt% to about 0.09 wt%, or about 0.04 wt% to about 0.09 wt%, or about 0.01 wt% to about 0.80 wt%, or about 0.01 wt% to about 0.60 wt%, or about 0.01 wt% to about 0.40 wt%, or about 0.10 wt% to about 0.50 wt%, or about 0.3 wt% to about 0.75 wt%, or about 0.40 wt% to about 0.60 wt%, or about 0.50 wt%, by weight of mineral wool fibers, may be added to the mineral wool fibers. As the amount of water repellant adhered to the fibers increases, the density of the resulting fiberboard decreases and the eNRC value of the fiberboard increases, which represents a more porous mat structure and the water retention value of the fiberboard decreases, resulting in significant energy savings during processing due to less water remaining driven in the convection dryer. At higher incorporation levels, for example, from about 0.10 wt% to 0.45 wt% or more by weight of the treated mineral wool, the physical properties of the fiberboard, such as hardness, MOR and MOE values, may be negatively impacted relative to an equivalent fiberboard comprising mineral wool that is not treated with a water repellent. The decrease in strength can be compensated by increasing the amount of starch in the fiberboard. Thus, in some embodiments, the fiberboard further comprises starch. As the amount of water repellent is reduced, Total Hydrocarbon (THC) emissions as a result of the water repellent are reduced. Thus, to balance the sound-deadening properties, strength properties, and environmental concerns, a water-repellent agent may be added in an amount of about 0.01 wt% to about 1.00 wt%, or about 0.01 wt% to about 0.20 wt%, based on the weight of the mineral wool. The amount of water repellant provided on the fibers can be determined by Loss On Ignition (LOI), which is the percent mass loss of the sample after exposure to an oven at 1000 ° f (about 538 ℃) for 1 hour.

The mineral wool may further be contacted with a dedusting agent to improve industrial hygiene. Dusting agents are generally hydrophilic agents that do not provide advantageous properties to the final fiber board. The dedusting agent may be partially supplemented or completely replaced by a water repellant. Further, in embodiments that include both a dedusting agent and a water repellant, the dedusting agent may be applied to the mineral wool before, simultaneously with, or after contacting the water repellant emulsion with the mineral wool. By supplementing or replacing the dedusting agent with a water repellant, industrial hygiene can be achieved with a reduced amount of agent that does not provide a benefit to the final board. Rather, the use of a water repellent in combination with or in place of a dusting agent allows for the production of a final fiberboard having advantageous density and/or water retention characteristics.

Methods of drying mineral wool are well known in the art and may include drying in a convection oven, for example.

Method for producing fiber board

A fiberboard comprising a mineral wool surface treated with a water repellent can generally be prepared by: surface-treating mineral wool with a water repellent agent to obtain water-repellent surface-treated mineral wool, blending the water-repellent surface-treated mineral wool with water to obtain a slurry, and dehydrating and drying the slurry to obtain a fiberboard.

The water repellent surface treated mineral wool may be prepared as described previously. Generally, the surface treatment of mineral wool with a water repellent is a separate step from the preparation of the slurry and is a step performed before the preparation of the slurry. Thus, in some embodiments, the slurry prepared by blending the surface treated mineral wool with water is substantially free of additional water repellent, i.e., substantially free of water repellent that is not introduced by the addition of the pretreated mineral wool. As used herein, "substantially free of water-repellent agents," when used to describe a slurry, means that the slurry does not contain a substantial amount of water-repellent agents. Thus, incidental or background amounts of water repellents (e.g., less than about 100ppb) may be present in the slurry (e.g., which leaches from the surface treated mineral wool) and are within the scope of the present disclosure.

The blending of mineral wool with water to make a slurry is well known in the art. The blending of the surface-treated mineral wool with water is not particularly limited as long as the components of the slurry are uniformly distributed. Other fiberboard components, including but not limited to fillers, colorants and binders, may be blended with the surface treated mineral wool and water. When other components are included, such components may be blended with the mineral wool at the same time, or may be mixed with water, either before or after the addition of the surface treated mineral wool.

Suitable fillers may include exfoliated or expanded glass-derived lightweight inorganic aggregates including, but not limited to, expanded perlite, vermiculite, expanded vermiculite, clay, exfoliated clay, and pumice, or the mineral aggregates may be higher density mineral aggregates including, but not limited to, stucco (calcium sulfate hemihydrate), gypsum, and limestone.

The binder may include one or more of starch, latex, and recycled paper products. The combination of starch and recycled paper products has been found to provide useful properties, but other binder components and/or combinations may of course be used. Organic binders (e.g., starch) are typically the primary component that provides structural adhesion to the resulting fiber board. Starch is a preferred organic binder because, among other reasons, it is relatively inexpensive. Typical starches include unmodified starches including, but not limited to, unmodified corn starch. Cellulosic fibers (an example of organic fibers) serve as the structural element of the final fiberboard. Cellulose fibers are typically provided in the form of recycled newsprint. In addition to or as an alternative to newsprint, "over-distributed newspapers" (OIN) and "old magazines" (OMG) may be used.

The slurry of the present disclosure can be used to prepare acoustical panels according to, for example, a wet mat production process. One version of this method is described in U.S. patent No. 5,911,818, which is incorporated herein by reference in its entirety. Generally, the aqueous slurry is delivered to a moving foraminous wire of a fourdrinier-type mat-forming machine. The slurry is first dewatered by gravity and then further dewatered by means of vacuum suction. The resulting dewatered slurry is then dried in a heated oven or kiln to remove residual moisture and form a dried basemat. The drying step is generally the most time consuming and expensive step in the production of the basemat. Since the dewatered slurry may take several hours to dry in an oven or kiln, the amount of fiberboard produced is limited by the amount that can be dried. Thus, the more water that can be removed during the gravity dewatering step and/or the less water that is initially incorporated into the slurry, the less time it takes for the dewatered slurry to dry in the oven, the lower the cost of the fiber board that will be produced, and the number of fiber boards that can be advantageously increased.

The dewatered slurry may be dried at any suitable temperature. In an embodiment, the dewatered slurry may be dried at a temperature of about 300 ℃ (about 150 ℃) to about 600 ° f (about 315 ℃), about 400 ° f (about 205 ℃) to about 600 ° f (about 315 ℃), or about 450 ° f (about 230 ℃) to about 550 ° f (about 290 ℃), such as about 300 ° f, about 250 ° f, about 400 ° f, about 450 ° f, about 500 ° f, about 550 ° f, or about 600 ° f.

Panels of acceptable size, appearance and sound damping characteristics are obtained by finishing the dried base mat. Finishing includes surface grinding, cutting, perforating, splitting, roll coating/spraying, edge cutting and/or laminating the board to a scrim, mesh or veil.

Fiber board

A fiberboard comprising the water repellent surface-treated mineral wool of the present disclosure (i.e., mineral wool having a surface pretreated with a water repellent) may be prepared using the methods disclosed herein. The fiberboard may be characterized using a number of characteristics including, but not limited to, density (porosity), acoustical properties (NRC and CAC values), physical properties (hardness, modulus of elongation (MOE) value, modulus of rupture (MOR) value), THC emissions, water swell value and water retention value of the cotton fibers, which are related to the time and energy required to dry the fiberboard.

Generally, the density of the fiberboard decreases as the water repellent agent provided on the mineral wool fibers increases. Without wishing to be bound by theory, it is believed that due to the repulsive forces between the surface treated mineral wool and the slurry water, the mineral wool fibers are dispersed in the slurry such that the spacing between each fiber and the other fibers is further relative to the performance of the non-surface treated fibers. It is believed that the increase in pitch continues into the dewatered slurry, and ultimately into the dried fiberboard, such that the pore size in the fiberboard according to the present disclosure is greater than that produced from untreated cotton, thereby making the density of the fiberboard according to the present disclosure less than that of an equivalent board made from untreated cotton. In some embodiments, the density of the fiberboard according to the present disclosure is maintained relative to an equivalent fiberboard in which the mineral wool is not surface treated. In some embodiments, the density of the fiberboard according to the present disclosure is reduced relative to an equivalent fiberboard in which the mineral wool is not surface treated. In an embodiment, the fiberboard of the present disclosure may be characterized by a density reduction in the range of about 0.4-0.6 pounds per cubic foot (pcf) relative to an equivalent fiberboard in which the mineral wool is not surface treated.

In general, the acoustical properties of fiberboard are affected by the porosity and density of the fiberboard. For example, the noise reduction coefficient ("NRC") represents the fraction of sound reaching the panel that is absorbed. The baffle with an NRC value of 0.60 absorbs 60% of the sound generated by the impact and deflects 40% of the sound. The NRC can be estimated by using an impedance tube as described in ASTM C384 to estimate NRC ("eNRC"). eNRC increases with increasing porosity and decreasing density of the fiberboard. Thus, if a high NRC is desired, a porous low density board may be provided. In embodiments, the fiber board of the present disclosure is characterized by an increase in eNRC value of at least 0.05, such as about 0.05, about 0.06, about 0.07, or about 0.08, relative to an equivalent fiber board wherein the fibers are not surface treated. In some embodiments, the fiber board of the present disclosure is characterized by an increase in eNRC value of about 10% to about 20% based on the eNRC value of an equivalent fiber board in which the mineral wool is not surface treated.

The physical properties of the fiberboard used to characterize the strength of the board include, for example, hardness values, MOE values and MOR values. The strength of a fiberboard is generally inversely proportional to density relative to an equivalent fiberboard of the same composition but of a different density. The loss of strength due to loss of density can be compensated for by including starch (or additional starch) in the fiber board composition.

The THC emission value of the fibreboard depends on the composition of the fibreboard. The THC emission value of a fiberboard comprising the surface treated mineral wool of the present disclosure is directly proportional to the amount of water repellent applied to the mineral wool. For example, for a fiberboard of the present disclosure including mineral wool having a surface pretreated with a water repellant in a range of about 0.25 wt% to about 1.0 wt% by weight of the mineral wool, the THC emissions may be about 5% to about 25% higher than the THC emissions of an equivalent fiberboard in which the mineral wool is not treated with a water repellant. In contrast, for a fiberboard of the present disclosure including mineral wool having a surface treated with a pre-water repellant in a range of about 0.01 wt% to about 0.09 wt% by weight of the mineral wool, the THC emissions may be about 1% to about 12% lower than the THC emissions of an equivalent fiberboard in which the mineral wool is not treated with a water repellant.

The water holding value of a fiberboard relates to the amount of water remaining after dewatering the slurry. The higher the water holding value, the more water must be removed during drying to form the fiberboard. Without wishing to be bound by theory, it is believed that because the mineral wool treated with the water repellent has a reduced wettability relative to the mineral wool not treated with the water repellent, the adhesion between the fibers of the surface-treated mineral wool and water is reduced and the fibers retain less moisture during the dewetting process. A fiberboard comprising mineral wool having a surface pretreated with a water repellent agent may be characterized by a water retention value of at least about 25lbs/MSF, at least about 50lbs/MSF, at least about 75lbs/MSF, or at least about 100lbs/MSF relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent agent. In an embodiment, the board of the present disclosure is characterized by a reduction in water holding capacity of about 50lbs/MSF relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent. Optionally, the board of the present disclosure is characterized by a reduction in water holding capacity of about 100lbs/MSF relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent.

The fiber board of the present disclosure can also be characterized by the water swell value of the cotton fibers included in the board. Generally, the higher the swell value of the water, the more dispersed the mineral wool fibers are in the slurry and the lower the density of the resulting fiber board. The fiberboard of the present disclosure is characterized by at least a 30%, at least a 40%, at least a 45%, or at least a 50% increase in water swell of the cotton fiber relative to cotton fiber provided in an equivalent fiberboard wherein the mineral wool is not treated with a water repellent.

Determination of water expansion value

The water swell value is generally determined as follows. 50 grams of cotton was mixed with 950 grams of water and the mixture was agitated for 10 minutes. The resulting slurry was immediately poured into a 1000ml graduated cylinder and allowed to stand for 10 minutes. After a settling time of 10 minutes, the volume reading of the cotton pulp (in ml) represents the swelling value.

Determination of ENRC values

The eNRC value is an estimated noise reduction coefficient determined by the impedance tube test method. Briefly, the standard test method for acoustical insulation resistance and absorption detailed in astm e1050-98 uses one tube, two microphones and a digital frequency analysis system. The results included spectral results of 250Hz, 500Hz, 1000Hz, and 2000Hz, and the arithmetic mean of the four frequencies represented the eNRC of the sound insulating material.

Determination of Water holding Capacity

The water hold-up value is the total weight of water held in the wet board (i.e., dewatered slurry) per 1000 square feet of surface area of board product prior to oven drying. The water hold-up value was determined by subtracting the dry board weight/1000 square foot board surface area from the total wet board weight/1000 square foot board surface area.

Determination of MOR and hardness values

MOR and hardness values were determined according to ASTM C367 using an Instron machine or equivalent. In short, the samples were about 3 "wide and about 10" long. The bearing surface spans about 8 ". A load was applied to the center of the specimen at a crosshead speed of about 1.97 inches/minute until failure occurred. The modulus of rupture is calculated according to the following formula:

MOR＝3PL/(2bd²)

where P is the maximum load (in lbf), L is the length of the span (in inches), b is the width of the specimen (in inches), and d is the thickness of the specimen (in inches).

The panels and methods according to the present disclosure may be better understood in light of the following examples, which are intended as illustrations of the panels and methods of the present disclosure only, and are not intended to limit the scope thereof in any way.

Examples of the invention

Example 1

Mineral wool is surface treated with linear polydimethylsiloxane by immersing the wool in a dilute solution of polydimethylsiloxane emulsion. Specifically, 0.625 and 2.50 grams of linear polydimethylsiloxane emulsions were mixed with 2000 grams of water and 250 grams of cotton, respectively, to provide emulsion solutions having linear polydimethylsiloxane concentrations of about 0.031 wt% and about 0.125 wt%. The untreated mineral wool was completely immersed in the emulsion solution for 10 minutes. The treated mineral wool was dried in an oven at 240 ° f (about 116 ℃) for about 4 hours. The treated cotton was tested to determine Loss On Ignition (LOI) and to determine the amount of water repellent adhering to the surface of the cotton. The treated cotton adhered to the surface of the cotton in an amount of about 0.13 and 0.45 weight percent water repellent.

The treated mineral wool was used to prepare fibreboards. In particular, mineral wool is blended with perlite, starch, newspaper, and water to form a homogeneous slurry. The slurry was dewatered using a Tappi forming machine. The resulting dewatered slurry was dried in an oven at 500 ° f (260 ℃) for 1 hour, and then in an oven at 300 ℃ (149 ℃) for 3 hours to form a fiberboard (treated board No. 1). A control fiber board (control board No. 1) having the same composition as the treated board No. 1 was prepared under the same conditions as the treated board No. 1 except that the mineral wool was not surface-treated with linear polydimethylsiloxane. The fiberboard was tested for board density, eNRC, hardness, MOR and MOE, water holdup value and THC emissions.

The average densities of the fiber boards prepared using the surface treated mineral wool (treated board No. 1) were about 0.4 and 0.6pcf less than the density of control board No. 1, indicating that the mat structure was more porous. The eNRC of treated panel No. 1 was correspondingly increased by about 0.08 relative to the eNRC of control panel No. 1. However, the decrease in density negatively affected the physical properties (hardness, MOE and MOR) of the treated panel No. 1. It is desirable to adjust the starch content of the treated board to compensate for the negative effects of density reduction. The water retention value of treated panel No. 1 was advantageously reduced by about 3.9% and about 5.8% relative to control panel No. 1. Specifically, the water retention value for control plate No. 1 was about 1816lbs/MSF, while the water retention values for treated plate No. 1 were about 1717 and 1748 lbs/MSF. The THC emissions of the treated panel No. 1 were about 5% and 25% higher than the THC emissions of the control panel No. 1, respectively.

Thus, example 1 demonstrates the success of forming a fiberboard according to the present disclosure, including surface treated mineral wool made according to the present disclosure. The fiberboard according to the present disclosure has improved sound insulating properties (eNRC) and water retention properties relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent agent.

Example 2

Mineral wool having a surface pretreated with linear polydimethylsiloxane was prepared such that the mineral wool accounted for 0.04 wt.% or 0.09 wt.% after pretreatment, based on the total weight of the mineral wool. Specifically, the polydimethylsiloxane emulsion was diluted with water to 7.5 and 10 weight percent polydimethylsiloxane and pumped through a nozzle into the cupola collection chamber at a flow rate of 25 gallons per hour. The polydimethylsiloxane emulsion solution was atomized and evaporated to cool the fiberized cotton and coat its surface. The treated mineral wool was used to prepare fibreboards. In particular, mineral wool is blended with perlite, starch, newspaper, and water to form a homogeneous slurry. The slurry was dewatered using a fourdrinier machine. The resulting dewatered slurry was dried in an oven at 500 ° f (260 ℃) for 1 hour, and then in an oven at 300 ° f (149 ℃) for 3 hours to form a fiber board (treated board No. 2). A control fiber board (control board No. 2) having the same composition as the treated board No. 2 was prepared under the same conditions as the treated board No. 2 except that the mineral wool was not surface-treated with linear polydimethylsiloxane. The fiberboard was tested for board density, eNRC, hardness, MOR and MOE, water holdup value and THC emissions.

The average density of the fiberboard prepared using the surface-treated mineral wool (treated board No. 2) was equal to that of the control board No. 2. Due to similar densities, the eNRC of treated panel No. 2 was consistent with that of control panel No. 2, as expected. The physical properties (hardness, MOE and MOR) of the treated panel No. 2 were also consistent with the control panel No. 2, indicating that the physical properties of the treated panel No. 1 in example 1 were affected by the reduction in density, but not by the presence of the water repellent. The water retention value of treated panel No. 2 was advantageously reduced by about 10.5% and about 11.5% relative to control panel No. 2. In particular, the water retention value for control plate No. 2 was about 1944lbs/MSF, while the water retention values for treated plate No. 2 were about 1717 and 1745 lbs/MSF. The THC emissions of the treated panel No. 2 were about 1% and about 11% lower than the THC emissions of the control panel No. 2. The water swell of the treated cotton of treated panel No. 2 showed a significant improvement over the water swell of control panel No. 2. In particular, the treated fiber board had cotton fibers with water swell of about 920ml and 950ml compared to 650ml for the control board.

Thus, example 2 demonstrates the successful formation of a fiberboard according to the present disclosure, including surface treated mineral wool made according to the present disclosure. The fiberboard according to the present disclosure has improved water swell characteristics, water retention characteristics, and THC emissions relative to an equivalent fiberboard in which the mineral wool is not surface treated with a water repellent agent.

The foregoing description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications within the scope of the invention may be apparent to those having ordinary skill in the art.

All patents, publications, and references cited herein are incorporated by reference in their entirety. In the event of a conflict between the present disclosure and an incorporated patent, publication, or reference, the present disclosure should control.