Microfiber-filled nonwoven facing

Abstract

A method of forming spun fibers (e.g., glass fibers) having a more uniform or constrained fiber diameter and / or length distribution is disclosed. Spun fibers having improved property distributions across the fiber volume facilitate the formation of improved nonwoven fiber mats and products (e.g., coated glass facings) formed from the mats. The coated glass facings are suitable for use as facing materials, such as for gypsum or polyisocyanurate boards. Because the nonwoven mats are formed from a blend of smaller and larger fibers, and because the coating applied to the mats includes filler components having smaller and larger particle sizes, the faced wallboard can have improved air permeability properties, which allows for better prevention of leaks, blotching, and other visual defects.

Description

Cross-references to related applications

[0001] This application claims priority and any rights to International Application No. PCT / US2023 / 084225, filed December 15, 2023, and International Application No. PCT / US2023 / 084228, filed December 15, 2023, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The general concept of the present invention relates to apparatus and methods for fiberizing mineral fibers (such as glass fibers) from molten mineral materials using a rotary process, as well as articles relating to the fibers themselves and the fibers bonded together. Background Technology

[0003] The production of mineral fibers, such as glass fibers, via a rotary process is well known. See, for example, U.S. Patents 5,582,841; 7,856,853; 8,087,265; and 8,250,884, the entire disclosures of which are incorporated herein by reference. In such processes, molten glass is fed at high temperature into a metal rotator rotating at high speed. The rotator has a peripheral wall containing multiple orifices. The molten glass flows through the orifices by centrifugal force, forming a small-diameter stream of molten glass. The stream is directed downward toward a collection surface by an annular blower surrounding the rotator. The airflow generated by the blower fines the molten glass stream to an even finer diameter and cools the stream to form glass fibers. An annular burner is also positioned around the rotator, and combustion gases and heat from the burner are directed downward to provide a fiber-refining environment suitable for allowing the initial glass stream to be fined to the desired final diameter. The downward annular flow of hot gas facilitates the refining of the molten mineral material flow into mineral fibers by the blower, and also keeps the rotator at a temperature suitable for fiberization.

[0004] As an example, such as Figure 1 As shown, the fiber manufacturing apparatus or fiber generator 10 includes a centrifuge or rotator 12 fixed to a rotatable hollow shaft or mandrel 14. Specifically, the rotator 12 is fixed to a hub 54 of a sleeve 64 at the lower end of the rotatable shaft or mandrel 14. Rotating the rotator 12 by rotating the mandrel 14 is known in the art. The rotator 12 includes a base 16 extending from the hub 54 to a peripheral wall 18. A plurality of holes 20 are provided around the outer periphery of the peripheral wall 18 for centrifuging fibers 22 of a molten material (e.g., glass).

[0005] Molten glass stream 78 is supplied to the rotator 12. Conventional supply equipment 82 can be used to supply molten glass stream 78. Such molten glass supply equipment is well known in industry and will not be discussed in detail herein. The glass in stream 78 falls into chamber 42 of rotator 12 and is guided by centripetal force against the peripheral wall 18 and flows outward to form a glass deposit or head 90. The glass then flows through orifice 20 to form primary fibers 22, which are heated and stretched by burner 24 and annular blower 28.

[0006] Rotation of rotator 12 (e.g.) Figure 1 (As depicted by the circular arrow (a)) the molten glass is centrifuged through holes 20 in the rotator's peripheral wall 18 to form primary fibers 22. The primary fibers 22 are kept in a soft, available state by the heat from the annular burner 24. An annular blower 28 uses guided air through channels 30 to draw the primary fibers 22 and further refine them into secondary fibers 32 suitable for products such as wool insulation. The secondary fibers 32 are then collected on a conveyor (not shown) to form products such as glass wool bundles.

[0007] The hollow sleeve 64 is pressure-fitted into a drilled hole formed through the center of the hub 54 and locked in place by three circumferentially spaced locking pins 66. The upper end of the sleeve 64 is threaded into the lower end of the hollow tie rod 68. Preferably, the sleeve 64 is further cooled by water, which circulates through an annular cooling jacket 70 disposed around the mandrel 14 and the sleeve 64 and located above the hub 54. The sleeve 64 and the hub 54 are preferably made of a low thermal expansion alloy to minimize the difference in thermal expansion between them.

[0008] The radiation shield 52 may include multiple individual plates 52a, 52b, 52c. The plates may be connected to the hub 54 of the sleeve 64. The plates suppress convection from the base of the rotator and suppress the escape of infrared energy from the base of the rotator 12, and reduce the thermal gradient along the height of the peripheral sidewall 18, thereby suppressing devitrification within the glass head 90 and controlling the temperature of the glass as it passes through the aperture 20 at the lower edge of the peripheral sidewall 18. The uppermost shield 52a is preferably frustoconical to conform to the bottom wall 16 of the rotator 12. The lower shields 52b, 52c may be frustoconical or planar to allow space between the shields. The shield 52 may be formed of stainless steel or a refractory metal, such as Hastelloy alloy, a high-temperature alloy based on the transition metal nickel. A particularly suitable material for the shield is Hastelloy X alloy, which is available from Haines International (Kokomo, Indiana (USA)). HASTELLOY X alloy contains 47 wt% Ni, 22 wt% Cr, 18 wt% Fe, 9 wt% Mo, 1.5 wt% W, 0.1 wt% C, 1 wt% Mn (max), 1 wt% Si (max) and 0.008 wt% B (max).

[0009] The rotator 12 is clamped to the hub 54 (at the lower end of the mandrel 14) on the sleeve 64 by clamping ring 55. The sleeve disc 67 can be located below the radiant shield 52 to provide a stable flow pattern for the airflow containing the refined fibers. In this way, a more stable "veil" (i.e., annular flow of fibers and air downwards away from the rotator 12) is maintained. The sleeve disc 67 can have any shape sufficient to cover the bottom of the rotator 12 and a considerable portion of the radiant shield 52. Similar to the rotator 12, the sleeve disc 67 can be mounted on the hub 54.

[0010] Despite these (and other) advances in rotator technology, reliably and consistently forming glass fibers with desired fiber diameters and / or lengths via rotational forming processes remains a challenge. By way of example, the fiber diameter distributions of various conventional rotationally formed glass fibers are shown in... Figures 2A to 2D middle.

[0011] exist Figure 2A Figure 210 shows a graph illustrating the fiber diameter distribution of commercially available unbonded loosely filled (ULF) glass fiber materials. ULF fibers are rotationally shaped fibers that are not typically held together by adhesives. ULF fibers are commonly used in building insulation applications.

[0012] Referring to Figure 210, Table 1 shows various properties of this first ULF material. .

[0013]

[0014] Table 1

[0015] In Table 1, “Peak Index” refers to the peak identifier from left to right, where peaks are shown with dashed lines; “Peak Type” refers to the type of model used to fit the data; “Area Intg” refers to the integral area of ​​the fitted peak; “Area IntgP” refers to the percentage of the total integral area of ​​each fitted peak; “Center Grvty” refers to the center of the fitted peak; “Maximum Height” refers to the maximum value of the fitted peak; and “FWHM” refers to the width of the peak at half its maximum height.

[0016] exist Figure 2A In graph 210, rotating fibers with a target diameter of approximately 3.1 μm are produced, as measured using a known airflow method. Graph 210 represents the fiber diameter distribution measured and plotted as a percentage of fiber volume using a method conforming to ISO 13322-2. The data measured according to the ISO 13322-2 method (Camsizer) was analyzed using Peak Deconvolution App (v2.00) and OriginPro 2023 (constant baseline; fitting until convergence to obtain displayed results). OriginPro 2023 is data analysis software sold by OriginLab Corp. (Northampton, Massachusetts).

[0017] Ideally, 100% of the produced fibers would have a fiber diameter of approximately 3.1 μm. However, rotary fiber production is a complex process with many variables, only a few of which can be controlled. Therefore, the fiber diameter distribution (i.e., the area under the graph) shows that a large number of fibers have a diameter greater than 3.1 μm, with some fibers measured to have diameters approaching 25 μm. This wide variation in fiber diameter (e.g., from approximately 1 μm to approximately 25 μm) (where most fibers have a diameter greater than 6 μm) is less than ideal for a target fiber diameter of 3.1 μm. In other words, for many applications, reducing the variation in fiber diameter relative to the target fiber diameter and / or increasing the volume of fibers with diameters closer to the target fiber diameter can result in improved products / applications using the fiber.

[0018] exist Figure 2B Figure 220 shows a graph illustrating the fiber diameter distribution of another commercially available unbonded loosely filled (ULF) glass fiber material. ULF fibers are rotationally shaped fibers that are not typically held together by adhesives. ULF fibers are commonly used in building insulation applications.

[0019] Referring to Figure 220, Table 2 shows various properties of this second ULF material. .

[0020]

[0021] Table 2

[0022] In Table 2, “Peak Index” refers to the peak identifier from left to right, where peaks are shown with dashed lines; “Peak Type” refers to the type of model used to fit the data; “Area Intg” refers to the integral area of ​​the fitted peak; “Area IntgP” refers to the percentage of the total integral area of ​​each fitted peak; “Center Grvty” refers to the center of the fitted peak; “Maximum Height” refers to the maximum value of the fitted peak; and “FWHM” refers to the width of the peak at half its maximum height.

[0023] exist Figure 2B In plot 220, as measured using a known airflow method, the rotating fibers were measured to have an effective fiber diameter between 2.8 μm and 3 μm. Plot 220 represents the fiber diameter distribution when measured using a method conforming to ISO 13322-2 and plotted as a percentage of fiber volume. The data measured according to the ISO 13322-2 method (Camsizer) was analyzed using Peak Deconvolution App (v2.00) and OriginPro 2023 (constant baseline; fit until convergence to obtain displayed results). OriginPro 2023 is data analysis software sold by OriginLab Corp. (Northampton, Massachusetts).

[0024] Ideally, 100% of the produced fibers would have a fiber diameter within this effective range. However, rotary fiber production is a complex process with many variables, some of which can be controlled. Therefore, the fiber diameter distribution (i.e., the area under the graph) shows that a large number of fibers have diameters greater than this range (i.e., much greater than 3µm), with some fibers measured to have diameters close to 24µm. This wide variation in fiber diameter (e.g., from about 1µm to about 24µm) (where most fibers have a diameter greater than 6µm) is less than ideal for a target fiber diameter of 2.9µm (i.e., between 2.8µm and 3µm). In other words, for many applications, reducing the variation in fiber diameter relative to the target fiber diameter and / or increasing the volume of fibers with diameters closer to the target fiber diameter can result in improved products / applications using the fiber.

[0025] exist Figure 2C Figure 230 shows the fiber diameter distribution of another commercially available unbonded loosely filled (ULF) glass fiber material. ULF fibers are rotationally shaped fibers that are not typically held together by adhesives. ULF fibers are commonly used in building insulation applications.

[0026] Referring to Figure 230, Table 3 shows the various properties of this third ULF material. .

[0027]

[0028] Table 3

[0029] In Table 3, “Peak Index” refers to the peak identifier from left to right, where peaks are shown with dashed lines; “Peak Type” refers to the type of model used to fit the data; “Area Intg” refers to the integral area of ​​the fitted peak; “Area IntgP” refers to the percentage of the total integral area of ​​each fitted peak; “Center Grvty” refers to the center of the fitted peak; “Maximum Height” refers to the maximum value of the fitted peak; and “FWHM” refers to the width of the peak at half its maximum height.

[0030] exist Figure 2C In plot 230, as measured using a known airflow method, the rotating fibers were measured to have an effective fiber diameter between 2.8 μm and 3 μm. Plot 230 represents the fiber diameter distribution when measured using a method conforming to ISO 13322-2 and plotted as a percentage of fiber volume. The data measured according to the ISO 13322-2 method (Camsizer) was analyzed using Peak Deconvolution App (v2.00) and OriginPro 2023 (constant baseline; fit until convergence to obtain displayed results). OriginPro 2023 is data analysis software sold by OriginLab Corp. (Northampton, Massachusetts).

[0031] Ideally, 100% of the produced fibers would have a fiber diameter within this effective range. However, rotary fiber production is a complex process with many variables, some of which can be controlled. Therefore, the fiber diameter distribution (i.e., the area under the graph) shows that a large number of fibers have diameters greater than this range (i.e., much greater than 3µm), with some fibers measured to have diameters of 25µm or greater. This wide variation in fiber diameter (e.g., from about 1µm to about 25µm) (where most fibers have a diameter greater than 6µm) is less than ideal for a target fiber diameter of 2.9µm (i.e., between 2.8µm and 3µm). In other words, for many applications, reducing the variation in fiber diameter relative to the target fiber diameter and / or increasing the volume of fibers with diameters closer to the target fiber diameter can result in improved products / applications using the fiber.

[0032] exist Figure 2DFigure 240 shows a graph 240 illustrating the fiber diameter distribution of a commercially available specialty material in the form of chopped glass microfibers. These specialty glass fibers are rotationally shaped fibers that are chopped to shorten their length. The specialty glass fibers are not held together by adhesives. These specialty glass fibers can be used as reinforcing agents or filler materials.

[0033] Referring to Figure 240, Table 4 shows the various properties of this special glass fiber material. .

[0034]

[0035] Table 4

[0036] In Table 4, “Peak Index” refers to the peak identifier from left to right, where peaks are shown with dashed lines; “Peak Type” refers to the type of model used to fit the data; “Area Intg” refers to the integral area of ​​the fitted peak; “Area IntgP” refers to the percentage of the total integral area of ​​each fitted peak; “Center Grvty” refers to the center of the fitted peak; “Maximum Height” refers to the maximum value of the fitted peak; and “FWHM” refers to the width of the peak at half its maximum height.

[0037] exist Figure 2D In plot 240, the swirled fibers were marketed as having an effective fiber diameter of approximately 3.2 μm. Plot 240 represents the fiber diameter distribution measured using a method conforming to ISO 13322-2 and plotted as a percentage of fiber volume. The data measured according to the ISO 13322-2 method (Camsizer) was analyzed using Peak Deconvolution App (v2.00) and OriginPro 2023 (constant baseline; fit until convergence to obtain displayed results). OriginPro 2023 is data analysis software sold by OriginLab Corp. (Northampton, Massachusetts).

[0038] Ideally, 100% of the produced fibers would have a fiber diameter of approximately 3.2 μm. However, rotary fiber production is a complex process with many variables, only a few of which can be controlled. Therefore, the fiber diameter distribution (i.e., the area under the graph) shows that a large number of fibers have a diameter greater than 3.2 μm, with some fibers measured to have diameters approaching 24 μm. This wide variation in fiber diameter (e.g., from approximately 1 μm to approximately 24 μm) (where most fibers have a diameter greater than 5 μm) is less than ideal for a target fiber diameter of 3.2 μm. In other words, for many applications, reducing the variation in fiber diameter relative to the target fiber diameter and / or increasing the volume of fibers with diameters closer to the target fiber diameter can result in improved products / applications using the fiber.

[0039] In view of the above, there is an unmet need for a rotary fiber production method capable of producing glass fibers with improved fiber diameter and / or length distribution, a collection of fibers with improved distribution, and products / applications using said fibers. Summary of the Invention

[0040] In view of the above, modifications to the rotatable fiber forming process allow for the production of fibers with a more uniform fiber diameter and / or length distribution. The general concept of the present invention includes this new method for producing rotatable fibers, the new rotatable fibers themselves, adhesive formulations suitable for the new rotatable fibers, packaging of the rotatable fibers (e.g., with improved fiber distribution), nonwoven mats made from the new rotatable fibers, and downstream applications of the mats (e.g., wall panel finishes).

[0041] In one exemplary embodiment, a method for manufacturing mineral fibers (microfibers) is disclosed. The method includes: rotating a rotator having a peripheral wall comprising a plurality of holes; supplying molten mineral material to the rotating rotator to centrifuge the molten mineral material stream through the holes; mixing combustion air and combustion gas, and supplying the mixture to an annular burner positioned around the rotator; generating an annular guide airflow in a channel positioned between the annular burner and an annular blower; directing the hot gas and the annular guide airflow from the annular burner toward the rotator and the molten mineral material stream to heat the rotator and refine the molten mineral material stream into multiple mineral fibers; and directing a source of cooling air through a hollow sleeve extending through the rotator to a sleeve disk positioned below the rotator, wherein the cooling air is delivered to the sleeve disk at a rate of about 30 cubic feet per minute to about 60 cubic feet per minute.

[0042] In some exemplary embodiments, the sleeve plate is cooled to a temperature below 750 °F.

[0043] In some exemplary embodiments, the method further includes controlling the rotator to rotate at a rate of about 900 rpm to about 2,400 rpm. In some exemplary embodiments, the method further includes controlling the rotator to rotate at a rate of about 1,800 rpm to about 2,400 rpm.

[0044] In some exemplary embodiments, hot gas from the annular burner is directed toward the rotator and the flow of molten mineral material at a rate of about 240 cubic feet per minute to about 300 cubic feet per minute.

[0045] In some exemplary embodiments, the annular blower outputs approximately 410 cubic feet per minute of air to generate an annular guide airflow.

[0046] In some exemplary embodiments, the mineral fiber is glass fiber.

[0047] In some exemplary embodiments, the mineral fibers have an average diameter of less than 9 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 8 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 7 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 6 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 5 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 4 µm. In some exemplary embodiments, the mineral fibers have an average diameter of less than 3 µm.

[0048] In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has an average fiber diameter x; and wherein x is less than the median fiber diameter of the mineral fiber.

[0049] In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter y; wherein the mineral fiber has an average fiber diameter x; and wherein y < 2x. In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter y; wherein the mineral fiber has an average fiber diameter x; and wherein y < 3x.

[0050] In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter of less than 6.5 µm; wherein the mineral fiber has an average fiber diameter x; and wherein the standard deviation from x is less than 2.5 µm. In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter of less than 6.5 µm; wherein the mineral fiber has an average fiber diameter x; and wherein the standard deviation from x is less than 3.0 µm. In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter of less than 6.5 µm; wherein the mineral fiber has an average fiber diameter x; and wherein the standard deviation from x is less than 3.5 µm. In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter of less than 6.5 µm; wherein the mineral fiber has an average fiber diameter x; and wherein the standard deviation from x is less than 4.5 µm. In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a target production fiber diameter of less than 6.5 µm; wherein the mineral fiber has an average fiber diameter x; and wherein the standard deviation from x is less than 5.5 µm.

[0051] In some exemplary embodiments, the mineral fiber comprises at least 10,000 different fibers; wherein the mineral fiber has a fiber diameter distribution with two Gaussian peaks; wherein the two Gaussian peaks represent ≥85% of the mineral fiber volume; and wherein ≥40% of the mineral fiber volume is represented by a Gaussian peak corresponding to the smallest diameter of the mineral fiber.

[0052] In some exemplary embodiments, the mineral fibers do not contain any fibers with a diameter greater than 22 μm. In some exemplary embodiments, the mineral fibers do not contain any fibers with a diameter greater than 20 μm. In some exemplary embodiments, the mineral fibers do not contain any fibers with a diameter greater than 16 μm. In some exemplary embodiments, the mineral fibers do not contain any fibers with a diameter greater than 15 μm. In some exemplary embodiments, the mineral fibers do not contain any fibers with a diameter greater than 14 μm.

[0053] In some exemplary embodiments, the mineral fibers have an average formed (i.e., non-shrink) length greater than 50.8 mm (2 inches). In some exemplary embodiments, the mineral fibers have an average formed length ranging from about 76.2 mm (3 inches) to about 304.8 mm (12 inches). In some exemplary embodiments, the mineral fibers have an average formed length ranging from greater than 50.8 mm (2 inches) to less than or equal to 152.4 mm (6 inches).

[0054] In one exemplary embodiment, a package of microfibers is disclosed. The package includes at least 10,000 distinct fibers having an average fiber diameter x; and wherein the fiber diameter distribution has a standard deviation from x of less than 2.5 μm. In some exemplary embodiments, x < 3.0. In some exemplary embodiments, x < 3.5. In some exemplary embodiments, x < 4.5. In some exemplary embodiments, x < 5.5.

[0055] In some exemplary embodiments, the microfibers are rotationally molded fibers.

[0056] In some exemplary embodiments, the microfibers have an average diameter of less than 9 μm. In some exemplary embodiments, the microfibers have an average diameter of less than 8 μm. In some exemplary embodiments, the microfibers have an average diameter of less than 7 μm. In some exemplary embodiments, the microfibers have an average diameter of less than 6 μm. In some exemplary embodiments, the microfibers have an average diameter of less than 5 μm. In some exemplary embodiments, the fiber has an average diameter of less than 4 μm. In some exemplary embodiments, the fiber has an average diameter of less than 3 μm.

[0057] In some exemplary embodiments, the mineral fibers have an average formed (i.e., non-reduced) length greater than 50.8 mm (2 inches). In some exemplary embodiments, the mineral fibers have an average formed length ranging from about 76.2 mm (3 inches) to about 304.8 mm (12 inches). In some exemplary embodiments, the mineral fibers have an average formed length ranging from greater than 50.8 mm (2 inches) to less than or equal to 152.4 mm (6 inches).

[0058] In some exemplary embodiments, x is less than the median fiber diameter of the microfiber.

[0059] In some exemplary embodiments, 90% of the microfibers have a diameter of ≤ 1.525x.

[0060] In some exemplary embodiments, the microfibers have a curvature greater than 0.043.

[0061] In some exemplary embodiments, the microfibers have a curvature of at least 0.055.

[0062] In some exemplary embodiments, the microfibers have a curvature in the range of 0.050 to 0.060.

[0063] In some exemplary embodiments, the microfibers are glass fibers.

[0064] In some exemplary embodiments, the microfiber comprises at least 10,000 different fibers; wherein the mineral fibers have a fiber diameter distribution having a first Gaussian peak and a second Gaussian peak; and wherein the first Gaussian peak and the second Gaussian peak represent ≥85% of the microfiber volume.

[0065] In some exemplary embodiments, ≥40% of the microfiber volume is represented by the first Gaussian peak corresponding to the minimum diameter of the microfiber.

[0066] In some exemplary embodiments, the microfibers include an adhesive composition applied to the surface of the fibers; and the adhesive composition is an aqueous composition comprising water, a silane coupling agent, at least one organic acid and a cationic surfactant.

[0067] In some exemplary embodiments, the microfibers include an adhesive composition applied to the surface of the fibers; and the adhesive composition is an aqueous composition consisting essentially of water, a silane coupling agent, at least one organic acid and a cationic surfactant, or the like.

[0068] In some exemplary embodiments, the adhesive composition does not contain a film-forming agent.

[0069] In some exemplary embodiments, the adhesive composition has an active solids content of less than 5%.

[0070] In some exemplary embodiments, the adhesive composition (applied to mineral fibers) is substantially colorless, wherein ΔL The value ranges from -5 to +5.

[0071] In some exemplary embodiments, at least one organic acid is selected from acetic acid, succinic acid, citric acid, and combinations thereof.

[0072] In some exemplary embodiments, the amount of adhesive composition applied to the microfibers is from about 0.05% by weight to about 2% by weight, based on the total weight of the sizing microfibers.

[0073] In one exemplary embodiment, a package of rotationally molded fibers is disclosed. The package includes: at least 10,000 different fibers, wherein the fibers have an average fiber diameter x; wherein the fiber diameter distribution of the fibers has a standard deviation from x of less than 3.5 μm; wherein the mineral fibers have a fiber diameter distribution having a first Gaussian peak and a second Gaussian peak; and wherein the first Gaussian peak and the second Gaussian peak represent ≥85% of the mineral fiber volume.

[0074] In an exemplary embodiment, a package of rotomolded fibers is disclosed. The package includes: at least 10,000 different fibers, where the fibers have an average fiber diameter x; where the fiber diameter distribution of the fibers has a standard deviation from x of less than 3.5 μm; where the mineral fibers have a fiber diameter distribution that has a first Gaussian peak and a second Gaussian peak; where the first Gaussian peak and the second Gaussian peak represent ≥85% of the volume of the mineral fibers; and where ≥40% of the volume of the mineral fibers is represented by the first Gaussian peak corresponding to the minimum diameter of the mineral fibers.

[0075] In some exemplary embodiments, a viscose composition for application to microfibers is disclosed. The viscose composition comprises water, a silane coupling agent, at least one organic acid, and a cationic surfactant, consisting essentially of or consisting of the foregoing.

[0076] In some exemplary embodiments, at least one organic acid is selected from acetic acid, succinic acid, citric acid, and combinations thereof.

[0077] In some exemplary embodiments, the viscose composition has a pH in the range of about 3.0 to about 7.5. In some exemplary embodiments, the viscose composition has a pH in the range of about 4.5 to about 5.5.

[0078] In some exemplary embodiments, the viscose composition has an active solids content of less than 5%.

[0079] In some exemplary embodiments, the cationic surfactant comprises about 25 wt% to about 90 wt% of the dry solids of the viscose composition.

[0080] In some exemplary embodiments, the silane coupling agent comprises about 15 wt% to about 45 wt% of the solids of the viscose composition; where the organic acid comprises about 1 wt% to about 20 wt% of the solids of the viscose composition; and where the cationic surfactant comprises about 35 wt% to about 75 wt% of the solids of the viscose composition.

[0081] In some exemplary embodiments, water comprises about 80 wt% to about 99.9 wt% of the viscose composition.

[0082] In an exemplary embodiment, a nonwoven mat is disclosed. The nonwoven mat includes: multiple first fibers; multiple second fibers (microfibers); and a binder that holds the first fibers and the second fibers together in an alternating arrangement; where the first fibers have an effective fiber diameter a; where the second fibers have an effective fiber diameter b; where b < a; where the second fibers have an average fiber diameter x of less than about 9 μm; and where the fiber diameter distribution of the second fibers has a standard deviation from x of less than 5.5 μm.

[0083] In some exemplary embodiments, x < 8. In some exemplary embodiments, x < 7. In some exemplary embodiments, x < 6. In some exemplary embodiments, x < 5.

[0084] In some exemplary embodiments, the standard deviation from x is less than about 4.5 μm. In some exemplary embodiments, the standard deviation from x is less than about 3.5 μm. In some exemplary embodiments, the standard deviation from x is less than about 3.0 μm. In some exemplary embodiments, the standard deviation from x is less than about 2.5 μm.

[0085] In one exemplary embodiment, a wallboard is disclosed. The wallboard includes: a gypsum core and a coated glass facing on at least one side of the core, wherein the coated glass facing includes a nonwoven mat. The nonwoven mat includes: multiple first fibers; multiple second fibers (microfibers); and a binder that holds the first and second fibers together in an alternating arrangement; wherein the first fibers have an effective fiber diameter a; wherein the second fibers have an effective fiber diameter b; wherein b < a; wherein the second fibers have an average fiber diameter x less than about 9 μm; and wherein the fiber diameter distribution of the second fibers has a standard deviation from x less than 5.5 μm.

[0086] In one exemplary embodiment, a thermal insulation board is disclosed. The thermal insulation board includes: a core of thermal insulation material and a coated glass facing on at least one side of the core, wherein the coated glass facing includes a nonwoven mat. The nonwoven mat includes: multiple first fibers; multiple second fibers (microfibers); and a binder that holds the first and second fibers together in an alternating arrangement; wherein the first fibers have an effective fiber diameter a; wherein the second fibers have an effective fiber diameter b; wherein b < a; wherein the second fibers have an average fiber diameter x less than about 9 μm; and wherein the fiber diameter distribution of the second fibers has a standard deviation from x less than 5.5 μm.

[0087] In some exemplary embodiments, the thermal insulation material is polyisocyanurate foam.

[0088] In one exemplary embodiment, a nonwoven mat is disclosed. The nonwoven mat includes: multiple first fibers; multiple second fibers (microfibers); and a binder that holds the first and second fibers together in an alternating arrangement; wherein the first fibers have an average fiber diameter greater than about 7 μm; wherein the second fibers have an average fiber diameter x less than about 6 μm; and wherein the fiber diameter distribution of the second fibers has a standard deviation from x less than 3.5 μm.

[0089] In some exemplary embodiments, the standard deviation from x is less than 3.0 μm. In some exemplary embodiments, the standard deviation from x is less than 2.5 μm.

[0090] In some exemplary embodiments, the second fiber has an average diameter of less than 5 µm. In some exemplary embodiments, the second fiber has an average diameter of less than 4 µm. In some exemplary embodiments, the second fiber has an average diameter of less than 3 µm.

[0091] In some exemplary embodiments, the second fiber has an average forming length greater than 50.8 mm (2 inches).

[0092] In some exemplary embodiments, the second fiber has an average forming length ranging from about 76.2 mm (3 inches) to about 304.8 mm (12 inches).

[0093] In some exemplary embodiments, the second fiber has an average forming length in the range of greater than 50.8 mm (2 inches) to less than or equal to 152.4 mm (6 inches).

[0094] In some exemplary embodiments, x is less than the median fiber diameter of the second fiber.

[0095] In some exemplary embodiments, 90% of the second fibers have a diameter of ≤ 1.525x.

[0096] In some exemplary embodiments, the second fiber has a curvature greater than 0.043.

[0097] In some exemplary embodiments, the second fiber has a curvature of at least 0.055.

[0098] In some exemplary embodiments, the second fiber has a curvature in the range of 0.050 to 0.060.

[0099] In some exemplary embodiments, the first fiber is glass fiber.

[0100] In some exemplary embodiments, the second fiber is glass fiber.

[0101] In some exemplary embodiments, the second fiber is a rotationally molded fiber.

[0102] In some exemplary embodiments, based on the weight of the nonwoven mat, the nonwoven mat contains at least 1% by weight of the second fiber. In some exemplary embodiments, based on the weight of the nonwoven mat, the nonwoven mat contains at least 10% by weight of the second fiber. In some exemplary embodiments, based on the weight of the nonwoven mat, the nonwoven mat contains at least 20% by weight of the second fiber.

[0103] In some exemplary embodiments, the average aspect ratio of the fiber combination is less than 1,000. In some exemplary embodiments, the average aspect ratio of the fiber combination is in the range of 500 to 1,000.

[0104] In some exemplary embodiments, the second fiber includes an adhesive composition applied to the surface of the second fiber; wherein the adhesive composition is an aqueous composition comprising, substantially comprising, or comprises of, water, a silane coupling agent, at least one organic acid and a cationic surfactant.

[0105] In some exemplary embodiments, the amount of adhesive composition applied to the second fiber is from about 0.05% by weight to about 2% by weight, based on the total weight of the second fiber to which the adhesive is applied.

[0106] In some exemplary embodiments, the adhesive includes polyvinyl alcohol.

[0107] In some exemplary embodiments, the nonwoven mat also includes inorganic fillers.

[0108] In some exemplary embodiments, the average fiber diameter of the first fiber is in the range of about 10 µm to about 11 µm; and the average fiber diameter of the second fiber is in the range of about 3 µm to about 4 µm.

[0109] In some exemplary embodiments, the second fiber does not contain any fibers with a diameter greater than 22 μm. In some exemplary embodiments, the second fiber does not contain any fibers with a diameter greater than 20 μm. In some exemplary embodiments, the second fiber does not contain any fibers with a diameter greater than 16 μm. In some exemplary embodiments, the second fiber does not contain any fibers with a diameter greater than 15 μm. In some exemplary embodiments, the second fiber does not contain any fibers with a diameter greater than 14 μm.

[0110] In some exemplary embodiments, the nonwoven mat has a first surface and a second surface opposite to the first surface, and each surface contains less than about 100 fibrous particles per 1,000 m³. 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 50 fuzz particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 25 fibrous particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 15 flocs / 1,000 m². 2 Nonwoven mat.

[0111] In some exemplary embodiments, the average fiber diameter of the first fiber is in the range of about 8µm to about 13µm.

[0112] In some exemplary embodiments, the average fiber diameter of the second fiber is in the range of about 3µm to about 3.5µm.

[0113] In some exemplary embodiments, the first fiber accounts for about 10% to about 50% of the total weight of the first and second fibers; and the second fiber accounts for about 50% to about 90% of the total weight of the first and second fibers.

[0114] In some exemplary embodiments, the nonwoven mat contains more first fibers than second fibers by weight, based on the total weight of the first and second fibers.

[0115] In one exemplary embodiment, a wall panel is disclosed. The wall panel includes: a plaster core and a coated glass finish on at least one side of the core, wherein the coated glass finish includes a nonwoven mat. The nonwoven mat includes: a plurality of first fibers; a plurality of second fibers (microfibers); and an adhesive that holds the first and second fibers together in an alternating arrangement; wherein the first fibers have an average fiber diameter greater than about 7 μm; wherein the second fibers have an average fiber diameter x less than about 6 μm; and wherein the fiber diameter distribution of the second fibers has a standard deviation of less than 3.5 μm from x.

[0116] In one exemplary embodiment, a heat insulation panel is disclosed. The heat insulation panel includes: a core of insulating material and a coated glass finish on at least one side of the core, wherein the coated glass finish comprises a nonwoven pad. The nonwoven pad comprises: a plurality of first fibers; a plurality of second fibers (microfibers); and an adhesive that holds the first and second fibers together in an alternating arrangement; wherein the first fibers have an average fiber diameter greater than about 7 μm; wherein the second fibers have an average fiber diameter x less than about 6 μm; and wherein the fiber diameter distribution of the second fibers has a standard deviation from x of less than 3.5 μm.

[0117] In some exemplary embodiments, the insulation material is polyisocyanurate foam.

[0118] In one exemplary embodiment, a method for manufacturing a nonwoven fiber mat is disclosed. The method includes: (i) dispersing a plurality of first fibers in a first aqueous solution to form a first slurry; (ii) dispersing a plurality of second fibers (microfibers) in a second aqueous solution to form a second slurry; (iii) mixing the first slurry, the second slurry, and a water-soluble or water-dispersible binder to form a third slurry; (iv) depositing the third slurry to form a wet-laid fiber web composed of the first fibers, the second fibers, and the binder; and (v) drying the wet-laid fiber web to form a nonwoven fiber mat, wherein the first fibers have an average fiber diameter in the range of about 6.5 μm to about 15 μm; wherein the second fibers have an average fiber diameter x of less than 6.0 μm; wherein the fiber diameter distribution of the second fibers has a standard deviation of less than 3.5 μm from x; and wherein the nonwoven mat has a first surface and a second surface opposite the first surface, wherein each surface has less than 100 flocs / 1,000 m². 2 Nonwoven mat.

[0119] In some exemplary embodiments, an adhesive is added to the first slurry.

[0120] In some exemplary embodiments, an adhesive is added to the second slurry.

[0121] In one exemplary embodiment, a coated glass finish is disclosed. The coated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers (microfibers), and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size of less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0122] In some exemplary embodiments, the second fiber has an average fiber diameter x µm of less than about 4 μm; and the second fiber constitutes y% of the weight of the pad, where y / x < 10.

[0123] In some exemplary embodiments, the primary adhesive includes a urea-formaldehyde adhesive. In some exemplary embodiments, the primary adhesive includes an acrylic adhesive.

[0124] In some exemplary embodiments, the first mineral filler is calcium carbonate, magnesium carbonate, talc, aluminum trihydrate, vermiculite, antimony oxide, titanium dioxide, aluminum trihydrate (Al2O3), clay, or a combination of any two or more of these substances. In some exemplary embodiments, the second mineral filler is calcium carbonate, magnesium carbonate, talc, aluminum trihydrate, vermiculite, antimony oxide, titanium dioxide, aluminum trihydrate (Al2O3), clay, or a combination of any two or more of these substances.

[0125] In some exemplary embodiments, the ratio of the first median granularity to the second median granularity is at least 1:3. In some exemplary embodiments, the ratio of the first median granularity to the second median granularity is at least 1:4. In some exemplary embodiments, the ratio of the first median granularity to the second median granularity is at least 1:5. In some exemplary embodiments, the ratio of the first median granularity to the second median granularity is at least 1:6.

[0126] In some exemplary embodiments, the ratio of the first median granularity to the second median granularity is in the range of 1:2 to 1:20.

[0127] In some exemplary embodiments, the second adhesive includes an acrylic adhesive.

[0128] In one exemplary embodiment, a wall panel is disclosed. The wall panel includes: a gypsum core and a coated glass finish on at least one side of the core. The coated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers (microfibers), and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size of less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0129] In one exemplary embodiment, a heat insulation panel is disclosed. The heat insulation panel includes: a core of heat-insulating material and a coated glass finish on at least one side of the core. The coated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers (microfibers), and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0130] In some exemplary embodiments, the thermal insulation material is polyisocyanurate foam.

[0131] In one exemplary embodiment, a coated glass veneer is disclosed. The coated glass veneer includes: a precursor mat that includes a plurality of first fibers, a plurality of second fibers (microfibers), and a primary binder that holds the first fibers and the second fibers together in an alternating arrangement; and a coating composition that includes a first mineral filler, a second mineral filler, and a second binder, where the first fibers have an effective fiber diameter a; where the second fibers have an effective fiber diameter b; where b < a; where the first mineral filler has a first median particle size less than about 4 μm; and where the second mineral filler has a second median particle size greater than about 8 μm.

[0132] In some exemplary embodiments, a > 9 µm.

[0133] In some exemplary embodiments, b < 9 µm.

[0134] In some exemplary embodiments, the second fibers have an average fiber diameter of x µm less than about 9 µm; the second fibers constitute y weight % of the mat; and y / x < 10. In some exemplary embodiments, the second fibers have an average fiber diameter of x µm less than about 9 µm; the second fibers constitute y weight % of the mat; and y / x < 8.

[0135] In some exemplary embodiments, the primary binder includes a urea formaldehyde binder. In some exemplary embodiments, the primary binder includes an acrylic binder.

[0136] In some exemplary embodiments, the first mineral filler is calcium carbonate. In some exemplary embodiments, the second mineral filler is calcium carbonate.

[0137] In some exemplary embodiments, the ratio of the first median particle size to the second median particle size is at least 1:3.

[0138] In some exemplary embodiments, the ratio of the first median particle size to the second median particle size is at least 1:4.

[0139] In some exemplary embodiments, the ratio of the first median particle size to the second median particle size is at least 1:5.

[0140] In some exemplary embodiments, the ratio of the first median particle size to the second median particle size is at least 1:6.

[0141] In some exemplary embodiments, the ratio of the first median particle size to the second median particle size is in the range of 1:2 to 1:20.

[0142] In some exemplary embodiments, the second adhesive includes an acrylic adhesive.

[0143] In one exemplary embodiment, a wall panel is disclosed. The wall panel includes: a gypsum core and a coated glass finish on at least one side of the core. The coated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers (microfibers), and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size of less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0144] In one exemplary embodiment, a heat insulation panel is disclosed. The heat insulation panel includes: a core of heat-insulating material and a coated glass finish on at least one side of the core. The coated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers (microfibers), and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0145] In some exemplary embodiments, the insulation material is polyisocyanurate foam.

[0146] In one exemplary embodiment (i.e., embodiment A), the coated or impregnated glass finish includes: a precursor pad comprising a plurality of first fibers, a plurality of second fibers, and a main binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an average fiber diameter greater than about 8 μm; wherein the second fibers have an average fiber diameter less than about 5 μm; wherein the first mineral filler has a first median particle size less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0147] In some embodiments of implementation scheme A, the second fiber has an average fiber diameter x µm of less than about 4 μm; the second fiber constitutes y% of the pad by weight; and y / x < 10.

[0148] In any of the aforementioned embodiments of implementation scheme A, the second fiber has an average fiber diameter x of less than about 4 μm; and the fiber diameter distribution of the second fiber has a standard deviation from x of less than 3.5 μm, preferably less than 3.0 μm, and even more preferably less than 2.5 μm.

[0149] In any of the aforementioned embodiments of Implementation Scheme A, the primary adhesive is selected from urea-formaldehyde adhesives, acrylic adhesives, and polyvinyl alcohol adhesives.

[0150] In any of the aforementioned embodiments of Implementation Scheme A, the first mineral filler is calcium carbonate, magnesium carbonate, talc, aluminum trihydrate, vermiculite, antimony oxide, titanium dioxide, aluminum trihydrate (Al2O3), clay, or a combination of any two or more of these substances.

[0151] In any of the aforementioned embodiments of Implementation Scheme A, the second mineral filler is calcium carbonate, magnesium carbonate, talc, aluminum trihydrate, vermiculite, antimony oxide, titanium dioxide, aluminum trihydrate (Al2O3), clay, or a combination of any two or more of these substances.

[0152] In any of the aforementioned embodiments of implementation scheme A, the ratio of the first median granularity to the second median granularity is at least 1:3, preferably at least 1:4, more preferably at least 1:5, even more preferably at least 1:6, and it should be noted that it is in the range of 1:2 to 1:20.

[0153] In any of the aforementioned embodiments of implementation scheme A, the second adhesive comprises an acrylic adhesive.

[0154] A board comprising a plaster core, wherein a coated or impregnated glass finish according to any of the foregoing embodiments of embodiment A is applied to at least one side of the plaster core.

[0155] A board comprising a core of insulating material, wherein a coated or impregnated glass finish according to any of the foregoing embodiments of embodiment A is applied to at least one side of the insulating core. In some exemplary embodiments, the insulating material forming the insulating core is selected from polyisocyanurate foam, mineral wool, polyurethane foam, polystyrene foam, and glass wool. In some exemplary embodiments, the polystyrene foam is extruded polystyrene (XPS) foam or expanded polystyrene (EPS) foam.

[0156] In one exemplary embodiment (i.e., Embodiment B), the coated or impregnated glass facing comprises: a precursor mat comprising a plurality of first fibers, a plurality of second fibers, and a primary binder holding the first and second fibers together in an alternating arrangement; and a coating composition comprising a first mineral filler, a second mineral filler, and a second binder, wherein the first fibers have an effective fiber diameter a; wherein the second fibers have an effective fiber diameter b; wherein b < a; wherein the first mineral filler has a first median particle size less than about 4 μm; and wherein the second mineral filler has a second median particle size greater than about 8 μm.

[0157] In some embodiments of Embodiment B, a > 9 μm.

[0158] In some embodiments of Embodiment B, b < 9 μm.

[0159] In some embodiments of Embodiment B, the second fibers have an average fiber diameter x µm less than about 9 μm; the second fibers constitute y weight % of the mat; and y / x < 10.

[0160] After reviewing the following description of various exemplary embodiments in conjunction with the accompanying drawings, other aspects and features of the general inventive concept will become more apparent to those of ordinary skill in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0161] The general inventive concept and its embodiments and advantages are described in more detail below by way of example with reference to the accompanying drawings, in which:

[0162] Figure 1 is a partial cross-sectional view of a rotary fiber forming apparatus to show aspects of a conventional rotary fiber production method.

[0163] Figure 2A is a graph showing the fiber diameter distribution of a certain volume of glass fibers produced by a conventional rotary fiber production method.

[0164] Figure 2B is a graph showing the fiber diameter distribution of a certain volume of glass fibers produced by another conventional rotary fiber production method.

[0165] Figure 2C is a graph showing the fiber diameter distribution of a certain volume of glass fibers produced by yet another conventional rotary fiber production method.

[0166] Figure 2D is a graph showing the fiber diameter distribution of a certain volume of glass fibers produced by yet another conventional rotary fiber production method.

[0167] Figure 3This is a partial cross-sectional view of a rotary fiber forming apparatus according to an exemplary embodiment, illustrating various aspects of a rotary fiber production method.

[0168] Figure 4 It shows through Figure 3 A curve showing the fiber diameter distribution of a certain volume of glass fiber produced by the rotary fiber manufacturing method.

[0169] Figures 5A to 5C This is a scanning electron microscope (SEM) image of an exemplary nonwoven mat made of fiber blends, in which fiber curvature was measured.

[0170] Figure 6 This is a graph showing the zeta potential (relative to pH) of several glass adhesive formulations.

[0171] Figure 7 This is an illustration showing exemplary nonwoven mat portions having and not having fibrous material.

[0172] Figure 8 This is a graph showing the “conversion value” between measuring the fiber diameter of various WUCS fibers with different fiber diameters using a SEM microscopy-based method and the method described herein in accordance with ISO 13322-2.

[0173] Figure 9 This is an illustration showing an exemplary treatment of the rotating fibers of the present invention before they are mixed with other fibers in a wet web forming process.

[0174] Figure 10 This is an illustration showing the thickness difference between a conventionally coated glass finish and a coated glass finish of the exemplary present invention as described herein.

[0175] Figure 11A This is a graph showing the various thickness measurement results of the nonwoven mat of the present invention and the control nonwoven mat. Figure 11B This is a graph showing the normalized tensile properties (obtained longitudinally) of the nonwoven mat of the present invention and the control nonwoven mat.

[0176] Figure 12 It is a graph showing the relationship between the amount of coating (coating added weight) applied to the first nonwoven pad of the present invention and the first control nonwoven pad and the resulting air permeability (Gurley value) of the respective pads.

[0177] Figure 13 It is a graph showing the relationship between the amount of coating (coating added weight) applied to the second nonwoven pad of the present invention and the second control nonwoven pad and the resulting air permeability (Gurley value) of the respective pads.

[0178] Figure 14This is another graph showing the relationship between the amount of coating (coating added weight) applied to the first nonwoven pad of the present invention and the first control nonwoven pad and the resulting air permeability (Gurley value) of the respective pads.

[0179] Figure 15 This is a diagram showing a first filler material (CaCO3-1) having a first particle size distribution, a second filler material (CaCO3-2) having a second particle size distribution, and a blend of the first and second filler materials (CaCO3-1+CaCO3-2) having a third particle size distribution.

[0180] Figure 16 This is a graph showing the various air permeability (Gurley value) measurements of the nonwoven mat of the present invention coated with a coating containing a single filler, the nonwoven mat of the present invention coated with a coating containing a blended filler, a control nonwoven mat coated with a coating containing a single filler, and a control nonwoven mat coated with a coating containing a blended filler. Detailed Implementation

[0181] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. As used herein, the term “about” to modify any numerical value covers the specific numerical value without any modification, and reasonable deviations from it, such as those attributable to the method of measurement or limitations.

[0182] Several exemplary embodiments will be described in detail. It should be understood that this disclosure is merely illustrative of the general inventive concept. Embodiments covering the general inventive concept may take various forms, and the general inventive concept is not intended to be limited to the specific embodiments described herein.

[0183] In view of the above, modifications to the spin fiber forming process allow for the production of fibers with a more uniform fiber diameter and / or length distribution. The overall inventive concept covers this new method for producing spin fibers, the new spin fibers themselves, adhesive formulations suitable for microfibers (including the new spin fibers), packaging of microfibers (e.g., new spin fibers with improved fiber distribution), nonwoven mats made from microfibers (including the new spin fibers), and downstream applications of the mats (e.g., wall panel finishes).

[0184] Rotational forming method / system

[0185] Nonwoven materials formed from glass fibers are known. For example, composite materials consisting of reinforced glass fiber mats (called, for example, veil, fiber web, finish) are used in a variety of applications.

[0186] One method of forming glass fibers involves passing molten glass through holes in the bottom of a fixed spinneret, where the molten glass flow thins into fibers as it cools. See, for example, US 3,653,860; US 3,972,702; and US 4,207,086. Another method of forming glass fibers involves passing molten glass through holes in the outer wall of a rotator (via centrifugal force), where the molten glass flow thins into fibers as it cools. See, for example, US 5,582,841. For rotationally formed fibers, heated air can be used to pull the fibers downward, which helps in the thinning and collection of the fibers.

[0187] The spinneret-formed glass fibers can then be chopped to form wet-cut chopped strands (WUCS) with relatively consistent average fiber diameter and average fiber length. However, due to health concerns associated with their non-biological solubility, spinneret-formed glass fibers are typically limited to fiber diameters of 6.5 μm or larger. Furthermore, the production of spinneret-formed glass fibers can be relatively more expensive than rotationally formed glass fibers due to factors such as raw material costs and production (melting) costs.

[0188] Therefore, for many applications, rotationally formed glass fibers are used instead of stencil-formed glass fibers, or rotationally formed glass fibers are used in addition to stencil-formed glass fibers. Due to their biosoluble formulation, rotationally formed glass fibers can have fiber diameters much smaller than 6.5 μm. Compared to WUCS fibers, these so-called “microfibers” can provide improved properties with a lower added weight. However, it has proven difficult to produce rotationally formed glass fibers with a consistent average fiber diameter and / or average fiber length.

[0189] As used herein (including in the claims), the term "microfiber" means a fiber having a target average fiber diameter of about 6.5 μm or less, and more preferably about 4 μm or less. Typically, but not exclusively, the microfiber will be rotationally formed fiber, such as the exemplary fibers shown in Table 6. Typically, but not exclusively, the microfiber will be glass fiber, and more preferably, biosoluble glass fiber. While the microfiber has a target average fiber diameter of 6.5 μm or less, due to production variability, specifically in the case of rotationally formed fibers, the distribution of a certain amount of fibers produced simultaneously may fall outside this range. For example, the average fiber diameter of the microfiber distribution can be as high as about 8.5 μm. Furthermore, the median (d) of the microfiber distribution... 50 The microfiber diameter can be as high as about 7.5 µm. As shown in Table 6, the standard deviation of the microfiber distribution from the actual average fiber diameter can be as high as about 5.5 µm, but more preferably less than about 3.5 µm.

[0190] One method for measuring the average fiber diameter (such as the average fiber diameter described herein) involves: (1) subjecting the sample to sufficient heat to burn off any surface chemicals without affecting the underlying fiber morphology; and (2) determining the average fiber diameter of that quantity of fibers by means of an airflow / pressure drop across the given quantity of fibers, as is commonly performed in the insulation and fiber industries (e.g., Micronaire). Instruments used to measure fiber diameter via airflow resistance are based on theories by Darcy, Les Fontaines Publiques de la Ville de Dijon (1856); Kozeny, Uber Kapillare Leitung des Wassers im Boden (1927); and Carman, Flow of Gases Through PorousMedia (1956), etc. The instrument works by measuring the airflow resistance through a known mass of material; as the fiber diameter decreases, the specific surface area increases, which increases the airflow resistance. The higher the airflow resistance, the smaller the effective fiber diameter, thus implying that if all fibers had the same diameter, the fiber diameter would be expected to produce the same resistance. Unless otherwise specified, this is the primary technique (referred to as the airflow resistance method) for obtaining the effective fiber diameter value (as an estimate of the average fiber diameter) presented herein (including in the claims).

[0191] However, the aforementioned airflow resistance method is not suitable for determining the distribution of individual fibers (e.g., fibers with different diameters) from a given amount of fiber or from values ​​calculated from the distribution (e.g., mean, median, standard deviation). Therefore, another method for measuring fiber diameter in the context of the overall fiber distribution (such as the fiber diameter distribution described herein) involves: (1) subjecting the sample to sufficient heat to burn off any surface chemicals without affecting the underlying fiber morphology; (2) dispersing the ordinary fibers in water using a high-speed blender; (3) diluting the dispersed fibers in water to an acceptable concentration suitable for image analysis; and (4) measuring the fiber diameter distribution using image analysis (e.g., conforming to ISO 13322-2). Image analysis can be performed using a device in which the particles (i.e., the dispersed fibers) pass through the focal plane of two cameras, having an image rate of 300 images / second and a resolution of 0.8 μm / pixel. The device used to obtain the data described herein is a Camsizer X2 with an X-Flow module, manufactured by Microtrac MRB (Osaka, Japan). The measured data can be filtered to remove non-fibrous particles (e.g., particles with an aspect ratio (L / D) of less than 5). Generally, at least 10,000 fibers are measured to ensure proper distribution assessment. The reported results are the Martin minimum diameter, binned in 0.1 micrometer increments, and plotted based on volume (not counted), where volume requires measurement of the average diameter and average length of each fiber. Unless otherwise noted, this image processing-based method (generally referred to herein as the method conforming to ISO 13322-2) is the primary technique for obtaining the average fiber diameter values ​​presented herein (including in the claims).

[0192] As is commonly used herein (including in the claims), unless the context otherwise requires, the term “average fiber diameter” encompasses both the effective fiber diameter and the average fiber diameter of the sample.

[0193] It should be noted that other methods exist for identifying the average fiber diameter and other distribution-related properties of fiber assemblies, such as counting-based methods for observing individual fibers identified using scanning electron microscopy (SEM). While these other methods are not directly related to the values ​​presented herein, it has been determined that measurements obtained by one method can be readily converted to the method disclosed herein by multiplying these values ​​by a constant transformation value. For example, as... Figure 8As shown in Graph 800, various samples made of non-rotating WUCS fibers with different fiber diameters were measured using both the SEM microscopy-based method and the ISO 13322-2 compliant method (referred to as Camsizer in Graph 800). The conversion between the SEM microscopy-based method value (α) and the ISO 13322-2 compliant method value (β) was determined by calculating the “fit line” between the various measurements, as follows: α = 0.76 × β.

[0194] In light of the above, modifications to the rotational fiber forming process allow for the production of fibers with a more uniform fiber diameter and / or length distribution. Therefore, the main disadvantages of rotationally formed fibers are mitigated, and the downstream processing of rotationally formed fibers is improved.

[0195] This will refer to conventional fiber manufacturing equipment or fiber forming equipment, such as Figure 1 The fiber-forming device 10 describes an improved rotary fiber forming method 300 (although the radiation shield 52 disclosed therein is an optional component). For example... Figure 3 As shown, the rotary fiber forming method 300 includes multiple aspects AE, which can be modified to produce fibers with a more uniform fiber diameter and / or length distribution. The general inventive concept covers an improved rotary fiber forming method 300 that uses any or more of these aspects AE to obtain a quantity of fibers (produced together) with a more uniform fiber diameter and / or length distribution. The general inventive concept covers any combination of these aspects (e.g., A, A+B, A+C, A+B+C, A+D, A+B+D, A+B+C+D, A+E, etc.). Furthermore, the general inventive concept is not necessarily limited to these aspects, and in some exemplary embodiments, other features of the invention, such as the adhesive formulations described herein, may also contribute to the improved fiber diameter and / or length distribution.

[0196] During conventional processing, the surface of the sleeve disk 67 of the fiber-forming unit 10 can become hot enough to melt the fibers in contact with the sleeve disk 67. In one aspect A of the improved rotary fiber forming method 300, the amount of cooling air introduced through the hollow sleeve 64 is increased, which lowers the temperature of the sleeve disk 67. By way of example, the conventional rotary fiber forming method would use an airflow of approximately 5 cubic feet per minute (CFM) to 15 cubic feet per minute (CFM) to cool the sleeve disk 67 to a temperature temp. 常规 The rotary fiber forming method of the present invention (e.g., method 300) uses an airflow of approximately 30 CFM to 60 CFM to cool the sleeve disk 67 to a temperature temp. 本发明 Therefore, although temp 常规 Typically much higher than 1,100℉ (e.g., ≥1200℉), but temp本发明 Keep below 1,100℉. Therefore, the forming fibers in contact with the sleeve disk 67 are unlikely to fuse with the sleeve disk (or with other fibers fused to the sleeve disk) in a way that could damage the fibers or cause fiber agglomeration (e.g., flocculent material), both of which could deform the intended fiber diameter and / or length distribution.

[0197] In another aspect B of the improved rotary fiber forming method 300, the rotational speed of the rotator 12 (via the rotating mandrel 14) is reduced, which decreases the likelihood of fibers contacting the surface of the blower 28. For example, a conventional rotary fiber forming method would operate the rotator 12 at 2,500 to 3,000 rpm, while the rotary fiber forming method of the present invention (e.g., method 300) would operate the same rotator 12 at 1,800 to 2,400 rpm. These ranges may vary for rotators with different sizes / geometries, but the reduction in rotational speed in the improved rotary fiber forming method will be maintained relative to the conventional rotary fiber forming method. Therefore, the formed fibers are less likely to fuse with (or with other fibers fused to them) in a manner that could damage the fibers or cause fiber agglomeration (e.g., flocculent material), both of which could distort the intended fiber diameter and / or length distribution.

[0198] In another aspect C of the improved rotary fiber forming method 300, the amount of heated air generated by the burner 24 is reduced. For example, a conventional rotary fiber forming method would use a mixed gas flow of approximately 360 cubic feet per minute (CFM), while the rotary fiber forming method of the present invention (e.g., method 300) would use a mixed gas flow of approximately 240-300 CFM. While reducing the gas flow at C helps lower the temperature within method 300, this must be balanced against the tendency for lower temperatures to result in larger diameter fibers due to reduced thinning. Therefore, in some exemplary embodiments, the improved rotary fiber forming method 300 may have a lower limit in its ability to produce fibers of smaller diameter and / or length. For example, the lower limit of the effective fiber diameter (using the airflow method) would be in the range of 2.5 μm to 3.0 μm, where this lower limit is limited by the ability to maintain sufficient temperature to thin the molten glass into fibers.

[0199] In another aspect D of the improved rotary fiber forming method 300, the amount of air introduced by the blower 28 through the channel 30 is controlled to promote improved thinning of the primary fiber 22 into the secondary fiber 32. In some exemplary embodiments of the rotary fiber forming method of the present invention (e.g., method 300), the blower 28 outputs approximately 410 cubic feet per minute (CFM), which in turn causes “guide air” to flow through the channel 30. Here, “improved thinning” can be considered as achieving a reduction in the occurrence of fused fibers and other defects (e.g., slag balls, flocculent material), as described herein. Similarly, this improved thinning (and the resulting reduction in fused fibers) is demonstrated by an improved fiber diameter and / or length distribution, such as… Figure 4 The curve is shown in graph 400.

[0200] The aforementioned aspect AD is particularly important relative to aspect E of the improved rotary fiber forming method 300, which represents the "refinement region" of the secondary fiber 32. The refinement region E is the area around the fiber generator 10 where the temperature is sufficiently high to fuse the fiber 32. The improved rotary fiber forming method 300 attempts to minimize collisions between the two individual fibers 32 and / or between the fiber 32 and components of the fiber forming device until the fiber 32 has cooled below its glass transition temperature T. g And therefore unlikely to fuse afterward. For example, for glass fibers with a Tg in the range of 1,000℉ to 1,250℉, the improved rotary fiber forming method 300 will attempt to minimize fiber collisions until the fibers have cooled to a temperature below 1,100℉.

[0201] In addition to producing a certain amount of fibers with a fiber diameter and / or length distribution that is closer to the target fiber diameter and / or length, the improved rotary fiber forming method 300 produces a certain amount of fibers with improved overall quality (e.g., longer length) compared to conventional rotary fibers by reducing the number of fibers that fuse and / or are damaged during the production process.

[0202] Furthermore, the fibers produced by the improved rotary fiber forming process 300 can be further processed downstream of method 300, such as by grinding / cutting / shredding the fibers to lengths that are easier to process. For example, the fibers can be ground to have a reduced length ranging from 1 / 8 inch (3.25 mm) to 1 inch (25.4 mm), which is beneficial for the use of the fibers in wet web forming methods. Similarly, other applications / methods can benefit from fibers with longer lengths. Therefore, because the fibers produced by the improved rotary fiber forming method 300 have a longer initial (forming) length than conventional rotary-formed fibers, the fibers are more likely to start at a length greater than the target length, which in turn provides greater flexibility in reducing the fibers to the target (processing) length and provides greater uniformity in products made from such fibers.

[0203] In this way, a wider range of aspect ratios can be obtained from the processed fibers, wherein the processed fibers have a more uniform distribution relative to the target aspect ratio. For example, the rotating fibers of the present invention can be processed to have an average aspect ratio in the range of 850 to 5,000 or in the range of 850 to 2,000. When blended with non-rotating fibers (e.g., WUCS fibers) having an aspect ratio of less than 2,000, the combined average aspect ratio of the fiber blend is less than about 1,000. This is advantageous because it has been found that controlling the average aspect ratio of the fiber blend helps to avoid or otherwise reduce the presence of fibrous material, bundles, fine threads, etc., all of which are considered undesirable forms of fibers within the blend.

[0204] The average aspect ratio of a given amount of similar fibers (e.g., fiber 1 or fiber 2) can be calculated by dividing the average fiber diameter d (μm) by the average fiber length L (μm), therefore, average aspect ratio = L / d. For a blend of two different fibers (e.g., fiber 1 and fiber 2), the combined average aspect ratio = (weight percentage of fiber 1) (Average aspect ratio of fiber 1) + (Weight % of fiber 2) The average aspect ratio of fiber 2). In addition, as described herein, when used to form nonwoven mats, the combined average aspect ratio of the fibers will typically be low (e.g., in the range of 150 to 500) due to breakage during the nonwoven fabric forming process.

[0205] In some exemplary embodiments, the combined average aspect ratio of the fiber blends is less than about 1,100. In some exemplary embodiments, the combined average aspect ratio of the fiber blends is less than about 1,000. In some exemplary embodiments, the combined average aspect ratio of the fiber blends is less than about 900. In some exemplary embodiments, the combined average aspect ratio of the fiber blends is in the range of about 500 to about 1,000.

[0206] Improved rotational molding fibers

[0207] exist Figure 4 The diagram 400 shows a graph of the fiber diameter distribution of a glass fiber material according to an exemplary embodiment. The glass fiber material comprises rotationally formed fibers not held together by an adhesive. The glass fiber material is formed by an improved rotational fiber forming method (e.g., method 300).

[0208] Referring to graph 400 and table 5, various properties of the glass fiber material of the present invention are shown. .

[0209]

[0210] Table 5

[0211] In Table 5, “Peak Index” refers to the peak identifier from left to right, where peaks are shown with dashed lines; “Peak Type” refers to the type of model used to fit the data; “Area Intg” refers to the integral area of ​​the fitted peak; “Area IntgP” refers to the percentage of the total integral area of ​​each fitted peak; “Center Grvty” refers to the center of the fitted peak; “Maximum Height” refers to the maximum value of the fitted peak; and “FWHM” refers to the width of the peak at half its maximum height.

[0212] exist Figure 4 In plot 400, the rotating fibers were produced with a target diameter of approximately 3.5 μm, as measured using a known airflow method. Plot 400 represents the fiber diameter distribution measured and plotted as a percentage of fiber volume using a method conforming to ISO 13322-2. The data measured according to the ISO 13322-2 method (Camsizer) was analyzed using Peak Deconvolution App (v2.00) and OriginPro 2023 (constant baseline; fitting until convergence to obtain displayed results). OriginPro 2023 is data analysis software sold by OriginLab Corp. (Northampton, Massachusetts).

[0213] Ideally, 100% of the produced fibers would have a fiber diameter of approximately 3.5 μm. However, rotary fiber production is a complex process with many variables, only some of which can be controlled. As described herein, improved rotary fiber forming methods (e.g., method 300) identify and control one or more production variables to obtain fibers with improved properties compared to conventional rotary fibers.

[0214] and Figures 2A to 2D Compared to conventional spun fibers shown in the curve graph, the spun fibers shown in curve 400 exhibit a more pronounced bimodal distribution. Specifically, curve 400 shows two distinct peaks, each with a apex exceeding 15% / μm within the distribution. Furthermore, the fiber diameter distribution (i.e., the area below the curve) shows that larger-volume fibers are closer to the target fiber diameter (i.e., 3.5 μm), with almost no fibers measuring diameters greater than 14 μm. This narrower variation in fiber diameter (e.g., from about 1.5 μm to about 13.5 μm) for the target fiber diameter of 3.5 μm is closer to ideal than that achieved by conventional spun fibers, where most fibers have a diameter less than 6 μm. In other words, the spun fibers of the present invention result in improved products / applications due to the reduced variation in fiber diameter relative to the target fiber diameter and / or the increased volume of fibers with diameters closer to the target fiber diameter.

[0215] In Table 6, the additional properties of the glass fiber material of the present invention (shown in graph 400) are compared with those of various conventional fiber materials (shown in graphs 210, 220, 230, and 240).

[0216]

[0217] Table 6

[0218] Wherein: d10 means that 10% of all particles in the sample are less than or equal to the d10 value; d50 means that 50% of all particles in the sample are less than or equal to the d50 value (also known as the median particle size); d90 means that 90% of all particles in the sample are less than or equal to the d90 value; the sample mean refers to the average particle size of the sample; and the standard deviation refers to the standard deviation from the mean.

[0219] Compared to the values ​​shown in Table 6, although the microfibers of the present invention do not have a lower median fiber diameter (d50) than all sampled conventional microfibers, they do have a lower average value than all sampled conventional microfibers. This indicates that the microfibers of the present invention contain less material with larger diameters (i.e., larger than the target fiber diameter), which can... Figure 2A , Figure 2B , Figure 2C , Figure 2D and Figure 4 As seen in the graph, a smaller standard deviation value also indicates that the microfibers of the present invention have a more uniform fiber diameter distribution, as described herein.

[0220] In addition, the present invention produces microfibers with increased fiber length compared to conventional microfibers.

[0221] By way of example, conventional rotary fiber forming methods produce rotary fibers (from fiber former 10) with lengths ranging from approximately 12.7 mm (0.5 inches) to 50.8 mm (2 inches), while the rotary fiber forming method of the present invention (e.g., method 300) produces rotary fibers (from fiber former 10) with lengths ranging from approximately 76.2 mm (3 inches) to 304.8 mm (12 inches). In some exemplary embodiments, the rotary fiber forming method of the present invention produces rotary fibers with an average forming length ranging from greater than 50.8 mm (2 inches) to less than or equal to 152.4 mm (6 inches). The ability to produce longer fibers provides increased flexibility in downstream fiber processing and greater control over the properties of the final product.

[0222] Furthermore, the microfibers of the present invention contain fewer fused fibers, clumps (e.g., flocs), or threads, thus enabling more uniform fiber dispersion when producing nonwoven products, as described herein. As used herein, the term "flocs" refers to loosely aggregated clumps of fibers visible to the naked eye. Figure 7 As shown in Figure 700, a sample portion of the nonwoven mat 710 is substantially free of any flocculent material 702 on one side 712 and / or on the side opposite to side 712 (not shown), however, a sample portion of another nonwoven mat 720 includes a number of flocculent materials 702 on one side 722 and / or on the side opposite to side 722 (not shown).

[0223] In some exemplary embodiments, the microfibers have an average fiber diameter of less than 6.5 µm. In some exemplary embodiments, the microfibers have an average fiber diameter of less than 5.5 µm. In some exemplary embodiments, the microfibers have an average fiber diameter of less than 4.5 µm.

[0224] In some exemplary embodiments, the microfibers have a fiber diameter distribution with one or two Gaussian peaks, the Gaussian peaks representing ≥85% of the fiber volume / mass, wherein ≥40% of the volume / mass is located at the peak representing the smallest diameter fiber.

[0225] In some exemplary embodiments, the microfibers are substantially free of any fibers with a diameter greater than 15 μm.

[0226] In some exemplary embodiments, as they are formed (e.g., leaving the fiber generator 10), the microfibers are substantially free of or significantly reduced in any unfibered or poorly fiberized material (often referred to as “slag balls”), fused fibers, agglomerated fibers (e.g., flocculents), and / or other forms of defective fibers, which can contribute to the improved fiber diameter distribution described herein.

[0227] In some exemplary embodiments, the microfibers are made from a biosoluble composition.

[0228] While non-rotating fibers (e.g., WUCS fibers) are inherently straight when formed, rotating fibers, in general, have curvature due to the glass fibers being cooled in a less controlled environment. This curvature can also impart beneficial effects to products made from microfibers (e.g., the rotating fibers of the present invention), such as reducing visual defects (e.g., cloudiness / spots; directionality) in ceiling tiles due to more random scattering of light and the fibers not aligning with each other.

[0229] like Figures 5A to 5CAs shown, several nonwoven mat samples were prepared using a wet web-forming process, which combined fiber blends comprising: (i) 11 μm diameter, 6 mm long WUCS fibers as the first fiber (fiber 1) and (i) 6.5 μm diameter, 6 mm long WUCS fibers as the second fiber. Figure 5A The second fiber (fiber 2) in the middle; (ii) Figure 2C The conventional ULF fiber shown is as Figure 5B The second fiber (fiber 2) in; and (iii) described herein and Figure 4 The rotating fiber of the present invention shown is as Figure 5C The second fiber (fiber 2) in the middle.

[0230] Figure 5A The image includes a SEM image of a nonwoven mat 500 made by a wet web forming process from a combination of 85% first WUCS fiber (fiber 1) and 15% second WUCS fiber (fiber 2) by weight of the glass fiber. The first WUCS fiber has an average fiber diameter of 11 μm and a processing length of 6 mm, and the second WUCS fiber has an average fiber diameter of 6.5 μm and a processing length of 6 mm. Figure 5B The image includes a SEM image of a nonwoven mat 502 made by a wet web forming process from a combination of 85% first WUCS fibers (fiber 1) and 15% second ULF fibers (fiber 2) by weight of the glass fiber. The first WUCS fibers have an average fiber diameter of 11 μm and a processing length of 6 mm, and the second ULF fibers have an average fiber diameter in the range of 2.8 μm to 3 μm and a processing length in the range of 1 mm to 6 mm. Figure 5C The image includes a SEM image of a nonwoven mat 504 made by a wet web forming process from a combination of 85% first WUCS fiber (fiber 1) and 15% second inventive rotating fiber (fiber 2) by weight of the glass fiber. The first WUCS fiber has an average fiber diameter of 11 μm and a processing length of 6 mm, and the second inventive rotating fiber has an average fiber diameter of 3.5 μm and a processing length in the range of 1 mm to 6 mm.

[0231] Pads 500, 502, and 504 were imaged using a scanning electron microscope to produce, respectively Figures 5A to 5CThe SEM images shown are illustrated. These SEM images were analyzed using the open-source software ImageJ version 1.54f, where the Kappa CurvatureAnalysis plugin (Gary Brouhard, 2016) approximates the curvature of the second fiber (fiber 2) in each of pads 500, 502, and 504. The WUCS fiber (fiber 2) in pad 500 was found to have a curvature of 0.004. The ULF fiber (fiber 2) in pad 502 was found to have a curvature of approximately 0.043. The inventive rotating fiber (fiber 2) in pad 504 was found to have a curvature of approximately 0.055.

[0232] In some exemplary embodiments, microfibers produced entirely by one or more fiber generators having substantially the same operating parameters (and possibly substantially simultaneously) are packaged together. In some exemplary embodiments, the microfibers may undergo processing (e.g., milling to reduce their length to “processed length”) prior to packaging. As described herein, the microfibers in the package may include an adhesive composition applied thereto. As described herein, the package of microfibers may have an improved fiber diameter and / or length distribution.

[0233] adhesive preparations

[0234] When microfibers (e.g., the rotating fibers of the present invention) are formed, or shortly thereafter, an aqueous adhesive composition can be applied thereto. For example, the adhesive composition can be sprayed onto the fibers using an annular ring with a nozzle surrounding a downward-pointing fiber curtain. The surface chemical properties imparted to the microfibers by the adhesive composition can protect the fibers and facilitate their downstream processing.

[0235] In one exemplary embodiment, an adhesive composition is provided. This adhesive composition comprises water, a silane coupling agent, at least one organic acid, and a cationic surfactant, wherein the adhesive composition has an active solids content of less than 5% and is substantially "colorless". Surprisingly, the subject adhesive composition comprising a reduced number of components has been found particularly suitable for the rotating fibers of the present invention compared to conventional adhesive compositions (e.g., conventional adhesive compositions used with WUCS fibers). Specifically, various exemplary aspects of the adhesive compositions disclosed herein do not contain film-forming agents. In some aspects, the reduced number of components results in an adhesive composition that is more cationic than conventional adhesive compositions, which provides improved dispersion of the sizing fibers in aqueous white water during the formation of a pad made of microfibers (e.g., the rotating fibers of the present invention).

[0236] The exemplary adhesive composition includes at least a silane coupling agent, at least one organic acid, and a cationic surfactant. In any of the embodiments, the adhesive composition may consist substantially of, or consist of, a silane coupling agent, at least one organic acid, and a cationic surfactant.

[0237] Silane coupling agents

[0238] Silane coupling agents can be in a partially or completely hydrolyzed state, or in a non-hydrolyzed state. Silane coupling agents can also exist in monomeric, oligomeric, or polymeric form before, during, or after their use.

[0239] Suitable silane coupling agents for the viscose compositions disclosed herein are organosilanes having silanol functional groups that are well bonded to glass (e.g., after hydrolysis of alkoxy groups). Silane coupling agents also contribute to processability, such as by reducing the level of broken fiber filaments during subsequent processing.

[0240] The silane coupling agent that can be used in the adhesive compositions of the present invention is characterized by functional groups of amino, methacrylate, epoxy, azide, vinyl, methacryloxy, urea, and isocyanate. Preferably, the organosilane has functional groups that are linked to silicon atoms by non-hydrolyzable bonds.

[0241] Organosilanes used in adhesive compositions include silanes containing the structure Si(OR)3, wherein R is an organic group, such as an alkyl group. Lower alkyl groups, such as methyl, ethyl, and isopropyl, are preferred. Examples of specific silane coupling agents suitable for adhesive compositions include, but are not limited to, γ-aminopropyltriethoxysilane (A-1100), γ-ureidopropyltrimethoxysilane (A-1524), 3-aminopropyltriethoxysilane (KBE-903), γ-glycidoxypropyltrimethoxysilane (A-187), γ-methacryloyloxypropyltrimethoxysilane (A-174), n-β-aminoethyl-γ-aminopropyltrimethoxysilane (A-1120), and methyl-trichlorosilane (A-...). 154), methyltrimethoxysilane (A-163), γ-mercaptopropyltrimethoxysilane (A-189), γ-chloropropyltrimethoxysilane (A-143), vinyltriethoxysilane (A-151), vinyltri-(2-methoxyethoxy)silane (A-2171), vinyltriacetoxysilane (A-188), octyltriethoxysilane (A-137), methyltriethoxysilane (A-162), and methyltrimethoxysilane (A-1630). All silane coupling agents listed herein are available as Silquest. ™The product is commercially available from Momentive Performance Materials, Inc. (Waterford, New York). In some exemplary embodiments, the silane coupling agent is selected from γ-aminopropyltriethoxysilane, γ-ureopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and combinations thereof.

[0242] In one exemplary embodiment, the adhesive composition comprises Silquest ® Y-9669, purchased from Momentive, is N-phenyl-γ-aminopropyltriethoxysilane with a solids content of 82%, and is similar to Silquest. ® A-1120 is N(β-aminoethyl)γ-aminopropyltrimethoxysilane with a solids content of 81%. An exemplary methacrylate-functionalized silane for use in the adhesive compositions disclosed herein is γ-methacryloyloxypropylmethoxysilane (A-174), commercially available from Momentive Performance Materials, Inc. (Waterford, New York). In another exemplary embodiment, the silane coupling agent component of the adhesive compositions disclosed herein comprises Silquest. ® Y-9669 and A-174.

[0243] In some exemplary embodiments, the adhesive composition includes a silane coupling agent in an amount such that the silane coupling agent accounts for 1% to 60% by weight of the solids content of the adhesive composition. In some exemplary embodiments, based on the total solids content of the adhesive composition, the silane coupling agent comprises 5% to 50% by weight of solids, including, for example, 15% to 45% by weight, and further comprises 25% to 35% by weight of solids. In some exemplary embodiments, the silane coupling agent has an active solids content of 25%-80%, including 40%-70% and 60%-65%.

[0244] organic acids

[0245] As described above, the exemplary adhesive compositions disclosed herein include at least one organic acid. The organic acid is used to adjust the pH to enable the hydrolysis of the silane coupling agent. The organic acids disclosed herein comprise at least one weak acid. Examples of suitable weak acids that can be used in the adhesive compositions disclosed herein include, but are not limited to, acetic acid, succinic acid, citric acid, and combinations thereof. In some exemplary embodiments, the weak acid component comprises or is composed of acetic acid. The adhesive compositions disclosed herein have a pH of about 3.0 to about 7.5, preferably about 4.5 to about 5.5.

[0246] In some exemplary embodiments, the adhesive composition includes an organic acid in an amount such that the organic acid accounts for 0.01% to 50% by weight of the solids content of the adhesive composition. For example, based on the total solids of the adhesive composition, the organic acid accounts for 0.05% to 40% by weight of the solids content of the adhesive composition, including 0.1% to 30% by weight, 0.5% to 25% by weight, 0.75% to 22% by weight, 1.0% to 20% by weight, 1.5% to 18% by weight, and 2.0% to 15% by weight. In some exemplary embodiments, the organic acid has 25% to 99%, including 40% to 90% and 70% to 85% of active solids content. In some exemplary embodiments, the organic acid has about 80% + / - 3% of active solids content.

[0247] cationic surfactants

[0248] The exemplary adhesive compositions disclosed herein also include cationic surfactants. The cationic surfactants act as “wet lubricants” and are used to increase the dispersibility of glass fibers in aqueous white water during the formation of a pad made of microfibers (e.g., the rotating fibers of the present invention).

[0249] Suitable examples of cationic surfactants include, but are not limited to, imidazoline and alkyl imidazoline derivatives, aminoethyl imidazoline, stearic acid alcohol amides such as Lubesize K-12 (Alpha / Owens Corning (Ontario, Canada)), polyamides of acetic acid, C5-C9 carboxylic acids, and diethylenetriamine-ethyleneimine, which can be used as Katax ® 6760L (Pulcra Chemicals) is commercially available. A preferred cationic softener is the acetate of the reaction product of tetraethylenepentamine and stearic acid, which is converted to approximately 91% imidazoline groups and is commercially available as LUBESIZE K-12.

[0250] Imidazolines are thermally stable organic nitrogenous bases. Unneutralized imidazolines are lipophilic and generally soluble in nonpolar solvents and mineral oils, but tend to be dispersible only in aqueous systems. The ability of imidazolines to form cations allows them to strongly adsorb onto negatively charged surfaces of metals, fibers, plastics, glass, and minerals, thereby converting these hydrophilic surfaces into hydrophobic ones. Imidazoline salts tend to be more hydrophilic than their bases and are used as acid-stable detergents with good wetting properties. The compatibility of imidazolines in aqueous systems can be improved by using suitable solubilizers.

[0251] In some exemplary embodiments, the adhesive composition includes a cationic surfactant in an amount such that the cationic surfactant accounts for 25% to 90% by weight of the total solids content of the adhesive composition. In some exemplary embodiments, based on the total solids content of the adhesive composition, the cationic surfactant comprises 30% to 80% by weight of solids, including, for example, 35% to 75% by weight, 37% to 72% by weight, and 40% to 70% by weight of solids, including all endpoints and subranges between the two. In some exemplary embodiments, the cationic surfactant has an active solids content of 0.5% to 20%, including 1% to 15% and 5% to 10%. In some exemplary embodiments, the cationic surfactant has an active solids content of about 9% + / - 3%.

[0252] As described above, the adhesive compositions disclosed herein can be formed in the absence of a film-forming agent material, which may comprise polymeric materials such as, for example, amide-based polymers, acrylic-based polymers, polyester-based polymers, epoxide-based polymers, etc. Traditionally, film-forming agents are included to aggregate and form a film on fibers during the drying of the adhesive composition. Film-forming agents serve to protect the fibers from damage during processing and to impart compatibility with other end-use materials. However, the adhesive compositions disclosed herein are formed using reduced amounts of chemicals and provide sufficient fiber protection without the use of a film-forming agent. However, various aspects of the exemplary adhesive compositions disclosed herein may optionally include a film-forming agent.

[0253] The exemplary adhesive compositions disclosed herein also include water. The adhesive composition contains an amount of water sufficient to dilute the solids of the adhesive composition to a viscosity suitable for application onto rotating fibers. According to some exemplary embodiments, the adhesive composition contains 80% to 99.9% by weight, including, for example, 85% to 98% by weight, or 90% to 99.5% by weight, of water based on the total weight of the adhesive composition. The total solids content of the adhesive composition can be from 0.5% to about 20% by weight, including 2% to 10% by weight. Preferably, the adhesive composition has a total solids content of 3% to 6% by weight, and more preferably about 5% by weight.

[0254] In some exemplary embodiments, the adhesive composition comprises, substantially comprises, or comprises the following: 25% to 35% by weight of a silane coupling agent, about 2% to 20% by weight of an organic acid, and 50% to 70% by weight of a cationic surfactant, based on the total solids content of the adhesive composition. In any of the exemplary embodiments, the adhesive composition may comprise or comprises: 25% to 35% by weight of a γ-aminopropyltriethoxysilane coupling agent, 2% to 20% by weight of acetic acid, and 50% to 70% by weight of an imidazoline derivative coupling agent, based on the total solids content of the adhesive composition.

[0255] The exemplary adhesive compositions disclosed herein may also include other components conventionally used in adhesive compositions. For example, the adhesive composition may optionally include wetting agents, surfactants, lubricants, antioxidants, dyes, oils, fillers, heat stabilizers, defoamers, dust suppressants, antimicrobial agents, antistatic agents, fungicides, biocides, film-forming agents, shredding aids, thickeners, and / or other conventional additives. Based on the dry solids content of the adhesive composition, the amount of the aforementioned optional components in the adhesive composition may range from 0% by weight to 90% by weight, including, for example, 0% by weight to 50% by weight, or 0% by weight to 30% by weight.

[0256] The exemplary adhesive compositions disclosed herein can be prepared by combining their components according to any method known to those skilled in the art. In some exemplary embodiments, the viscosity of the white water at room temperature is preferably greater than 2.0 cps, more preferably between 2.0 cps and 5 cps, and even more preferably about 3.0 cps to 3.5 cps.

[0257] Exemplary adhesive composition ranges are provided in Table 7 below. It should be understood that any of the disclosed ranges of adhesive compositions AC in Table 7 may be used in combination with any other disclosed composition ranges herein, and is not limited to the specific combinations of the ranges provided herein.

[0258]

[0259] Table 7

[0260] In some exemplary embodiments, the adhesive composition is essentially cationic. The charge of the adhesive composition can be described by its zeta potential over a pH range. Zeta potential is the charge generated at the interface between a solid surface (such as particulate material) and its liquid medium. The adhesive composition of the present invention has a zeta potential with an absolute value at least 20 greater than the pH. Specifically, the adhesive composition has a zeta potential with an absolute value greater than 30 in a pH range between 2 and 4. The adhesive composition has a zeta potential with an absolute value greater than 20 in a pH range between 2 and 6.

[0261] For illustrative purposes, the adhesive formulation (IF) of the present invention, which is formed according to the concept of the invention and has a cationic surfactant comprising about 70% by weight of solids, is compared with a first conventional reference adhesive formulation (RF-1) applied to an equivalent fiber and a second conventional reference adhesive formulation (RF-2) applied to another equivalent fiber. Both RF-1 and RF-2 contain about 20% to 40% by weight of cationic lubricant. In each case, the specific adhesive formulation is applied to conventional WUCS fibers at the same or lower weight percentage using a roll coating technique. Figure 6 In the figure, a graph of the zeta potential relative to pH was plotted for each formulation. Generally speaking, the larger the magnitude of the zeta potential, the more cations in the formulation.

[0262] As shown in graph 600, the larger zeta potential of IF at both high and low pH indicates that the sizing fiber exhibits amphipathic behavior, implying that it can act as either an acid or a base. This characteristic indicates that fibers sizing with IF disperse well in both acidic and alkaline environments. To achieve a suitable dispersion, a zeta potential with an absolute value greater than 20 is generally desired at pH between 2 and 6.

[0263] In addition, the total composition of adhesive chemicals (such as IF) contains more cationic lubricants, approximately 70% by weight solids, than that of conventional adhesive chemicals (such as RF-1, RF-2), which typically range from 0% to 40% by weight solids.

[0264] Compared to conventional adhesive compositions, the exemplary adhesive compositions disclosed herein can be substantially "colorless". In exemplary embodiments, the adhesive compositions disclosed herein exhibit a ΔL of -5 to +5 on fibers. Value. In some exemplary embodiments, the viscose compositions disclosed herein exhibit a ΔL value of 0 to +2.5 on fibers. Values, including +2 ΔL Value. In an exemplary embodiment, the adhesive composition disclosed herein exhibits a Δa value of -10 to +10 on fibers. Value. In some exemplary embodiments, the viscose compositions disclosed herein exhibit a Δa value of -8 to +2 on fibers. Values, including approximately -6 Δa Value. In an exemplary embodiment, the adhesive composition disclosed herein exhibits a Δb value of -10 to +10 on fibers. Value. In some exemplary embodiments, the adhesive compositions disclosed herein exhibit a Δb value of -5 to +5 on fibers. Values, including approximately 0 for Δb value.

[0265] The viscose composition can be applied to the fiber such that it is present on the fiber in an amount of 0.05 wt% to 2 wt% based on the total weight of the sizing fiber. The amount of viscose composition present on the fiber is also referred to as the "twist solids content". In some exemplary embodiments, the viscose composition is present on the fiber in an amount of 0.08 wt% to 1.0 wt% based on the total weight of the sizing fiber, including 0.1 wt% to 0.8 wt%, 0.2 wt% to 0.6 wt%, and further including an amount of 0.35 wt% to 0.55 wt% based on the total weight of the sizing fiber. This can be determined by the loss on ignition (LOI) of the sizing fiber, which is the weight reduction experienced by the sizing fiber after heating it to a temperature sufficient to cause the viscose composition to burn or pyrolyze from the fiber.

[0266] When evaluated based on the surface area of ​​the fibers, the adhesive compositions of the present invention can also be applied at lower levels. For example, microfibers (e.g., the rotary fibers of the present invention described herein) may have a surface area of ​​less than about 4 mg / cm² when applied thereon. 2 Including, for example, 0.5 mg / cm³ 2 -3.8mg / cm 2 0.75 mg / cm 2 -3.4mg / cm 2 1mg / cm 2 -3mg / cm 2 Or 1.15 mg / cm 2 -2.5mg / cm 2 The strand solid, however, conventional WUCS fibers can have a 4 mg / cm² applied to them. 2 -24mg / cm 2 The solid strand.

[0267] In an exemplary embodiment, the moisture content of the sizing fiber is less than 10%, including a final moisture content of less than 7%, less than 6%, and less than or equal to 5%. A reduction in the final moisture content (i.e., an increase in fiber dryness) can provide beneficial effects such as reduced transportation costs, while reducing / avoiding the need for antimicrobial agents in the viscose composition.

[0268] nonwoven mat

[0269] Microfibers, such as the rotating fibers of the present invention described herein, can be used to form other materials, such as nonwoven mats. Fiber mats can be formed by known methods, such as wet web forming processes. In a wet web forming process, discrete fibers are dispersed in an aqueous slurry containing surfactants, thickeners, defoamers, and / or other chemical reagents. The water and chemical components are commonly referred to as a “white water” solution. The slurry containing the fibers is then stirred in a mixing tank, causing the fibers to disperse throughout the slurry. The slurry containing the dispersed fibers is deposited onto a moving screen, where a significant portion of the water is removed to form a fiber web of randomly oriented fibers. A binder is applied to the fiber assembly, which is then passed through an oven to dry the fibers (i.e., remove any residual water from the fibers) and cure the binder to form a mat. In addition to being applied in an aqueous form, the binder can also be applied in a dry (powdered) form. For example, swellable polyvinyl alcohol (PVA) powder can be added to the fiber mixture, where the PVA binder effectively binds the fibers as they pass through the oven / dryer.

[0270] Generally, any adhesive suitable for forming conventional nonwoven fiber mats can be used. Exemplary adhesive compositions that can be used to produce nonwoven mats include formaldehyde-free (or formaldehyde-free (“NAF”)) adhesives, such as carboxyl-based adhesive compositions, polyvinyl alcohol-based adhesive compositions, carbohydrate-based adhesive compositions, etc. Such formaldehyde-free adhesives are environmentally friendly, i.e., “green.” In some embodiments, the adhesive may comprise one or more bio-based materials. However, in some exemplary embodiments, the adhesive composition may comprise a formaldehyde system, such as a urea-formaldehyde system.

[0271] The adhesive may include thermosetting or thermoplastic adhesives. For example, the adhesive may comprise a thermosetting adhesive, wherein at least one polycarboxylic acid polymer is used as the thermosetting adhesive resin. Polycarboxylic acid polymers include organic polymers or oligomers containing more than one side carboxyl group. The polycarboxylic acid adhesive may be a homopolymer or copolymer prepared from one or more unsaturated carboxylic acids, including, but not limited to, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaconic acid, α,β-methyleneglutaric acid, etc. Alternatively, the polycarboxylic acid adhesive may be prepared from unsaturated acid anhydrides, including but not limited to maleic anhydride, itaconic anhydride, acrylic anhydride, methacrylic anhydride, etc., and mixtures thereof. The polymerization of these acids and anhydrides is considered to be within the capabilities of those skilled in the art.

[0272] In some exemplary embodiments, the adhesive composition comprises a thermosetting acrylic package comprising a blend of a thermosetting hydrophilic acrylic adhesive material and a thermosetting hydrophobic acrylic adhesive material. The thermosetting acrylic package may include, but is not limited to, acrylic emulsions, acrylic solutions, or mixtures thereof. The thermosetting nature of the acrylic package reduces the tackiness of the adhesive and thus reduces adhesion of the adhesive to processing equipment during manufacturing. In some embodiments, the thermosetting acrylic package comprises a mixture of an acrylic homopolymer and a styrene-acrylic latex. Based on the total weight of the precursor adhesive solids, the acrylic homopolymer may be present in an amount of about 50% to about 80% by weight, or about 60% to about 75% by weight. Based on the total weight of the adhesive solids, the styrene-acrylic latex may be present in an amount of about 20% to about 45% by weight, or about 25% to about 40% by weight.

[0273] The adhesive composition may optionally include a defoamer. In some exemplary embodiments, the defoamer includes one or more of siloxanes, mineral oils, and polyoxyethylenes, but any defoamer may alternatively be used. Exemplary defoamers include polyether siloxanes, such as Tego. ® Foamex 1488 (available commercially from Evonik). In some exemplary embodiments, the defoamer is present in the binder composition in an amount from about 0.001% to about 1.0% by weight, including from about 0.01% to about 0.25% by weight, based on the total solids weight in the precursor binder composition.

[0274] In some embodiments, the adhesive composition may optionally contain at least one coupling agent. In some embodiments, the coupling agent is a silane coupling agent. The coupling agent may be present in the adhesive composition in amounts of 0.01% to 5% by weight (based on dry weight), 0.01% to 2.5% by weight (based on dry weight), 0.1% to 0.5% by weight (based on dry weight), or 0.15% to 0.25% by weight (based on dry weight).

[0275] Non-limiting examples of silane coupling agents that can be used in adhesive compositions may be characterized by functional groups, including but not limited to alkyl, aryl, amino, epoxy, vinyl, methacryloxy, urea, isocyanate, and mercapto groups. In some embodiments, the silane coupling agent comprises a silane containing one or more nitrogen atoms, the silane having one or more functional groups such as amines (primary, secondary, tertiary, and quaternary amines), amino, imino, amide, imide, urea, or isocyanate groups. Specific, non-limiting examples of suitable silane coupling agents include, but are not limited to, aminosilanes (e.g., γ-aminopropyltriethoxysilane and γ-aminopropyltrihydroxysilane), epoxytrialkoxysilanes (e.g., 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane), methacryloxytrialkoxysilanes (e.g., 3-methacryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltriethoxysilane), hydrocarbontrialkoxysilanes, aminotrihydroxysilanes, epoxytrihydroxysilanes, methacryloxytrihydroxysilanes, and / or hydrocarbontrihydroxysilanes.

[0276] The binder composition may also contain one or more additional additives, such as extenders, catalysts, processing aids, dust suppressants, viscosity modifiers, pH adjusters, crosslinking density enhancers, deodorizers, antioxidants, moisture-proofing agents, or combinations thereof. Optionally, the binder may contain, but is not limited to, dyes, pigments, additional fillers, colorants, UV stabilizers, heat stabilizers, emulsifiers, preservatives (e.g., sodium benzoate), corrosion inhibitors, and mixtures thereof. Other additives may be added to the binder composition to improve process and product performance. Such additives include lubricants, wetting agents, antistatic agents, and / or waterproofing agents. Additives may be present in trace amounts (such as about 0.1% or less by weight of the binder composition) up to about 10% by weight of the total solids in the binder composition in the precursor binder composition.

[0277] In some exemplary embodiments, the adhesive may constitute a filled adhesive that includes one or more primary fillers (e.g., mineral fillers). In this case, the primary filler may be present in the filled adhesive composition at a maximum of about 50% by weight of the total solids in the filled adhesive composition.

[0278] The binder composition includes water to dissolve or disperse active solids for application onto fibers. The amount of water added is sufficient to dilute the aqueous binder composition to a viscosity suitable for its application onto the fibers and to achieve the desired solids content on the fibers.

[0279] In some exemplary embodiments, the adhesive composition is included in the fiber mat in amounts ranging from about 10% to about 30% by weight, including between about 15% and about 27% by weight, and between about 16% and about 25% by weight.

[0280] Uniform fiber arrangement in nonwoven sheet-like fiber mats contributes to the mat's strength and the final product. Other beneficial effects, such as improved aesthetics, can also be achieved through increased fiber uniformity. One problem in preparing uniform fiber mats from aqueous dispersions is the difficulty in dispersing fibers (e.g., glass fibers) in the aqueous medium. This difficulty in dispersing fibers initially occurs when the fibers are added to water. Dispersibility is further complicated by the tendency of fibers that are slightly dispersed in the aqueous medium to re-agglomerate to some extent. Re-agglomerated fibers are very difficult to redisperse. The lack of good fiber dispersion in the aqueous medium hinders the formation of uniform mats and adversely affects the properties (e.g., strength, appearance) of the resulting sheet-like mat or the final product incorporating such a mat. This dispersion problem can be exacerbated when mixing smaller diameter fibers (e.g., microfibers) with larger diameter fibers (e.g., non-rotating fibers, such as WUCS).

[0281] A well-dispersed aqueous mixture can be obtained by any suitable means, provided that a uniform or substantially uniform distribution of two (or more) different sets of glass fibers is achieved in the aqueous medium. In some exemplary embodiments, a uniform distribution of two different sets of glass fibers is achieved. In some exemplary embodiments, a substantially uniform distribution of two sets of glass fibers is achieved. The dispersion can be obtained by high-shear mixing equipment, such as a rotor / stator mixer. Not wishing to be bound by theory, the inventors believe that highly dispersed and distributed mixing contributes to the production of fibrous nonwoven mats that have substantially no or only a small amount of undispersed or partially dispersed fibers (e.g., flocculent material) on each surface of the bonded nonwoven mat.

[0282] In some exemplary embodiments, the majority (e.g., at least 10% by weight) of, but not all, of the fibers used to form the nonwoven mat are microfibers, such as the rotationally formed fibers of the present invention described herein. In some exemplary embodiments, the nonwoven mat is formed from a blend of a first fiber and a second fiber (i.e., microfibers), wherein the first fiber has an average diameter >6.5 μm and the second fiber has an average diameter <6.5 μm. In some exemplary embodiments, the first fiber has an average diameter in the range of about 6.5 µm to about 15 µm. In some exemplary embodiments, the second fiber has an average diameter in the range of about 1 µm to about 6 µm. In some exemplary embodiments, both the first and second fibers are glass fibers. In some exemplary embodiments, the first fiber is not a rotationally formed fiber.

[0283] In one exemplary embodiment, the nonwoven mat comprises a blend of: a first fiber, wherein a first portion has an average diameter of about 11 μm and an average processing length of about 6 mm, and a second portion has an average diameter of about 13 μm and an average processing length of about 19 mm; a second fiber, having an average diameter of about 3.5 μm and an average processing length in the range of 1 mm to 6 mm; and a UF / acrylic adhesive. In this embodiment, based on the weight of the glass fibers in the mat, the mat comprises approximately 45 wt% of the first portion of the first fiber, approximately 45 wt% of the second portion of the first fiber, and approximately 10 wt% of the second fiber. Additionally, based on the weight of the mat, the mat contains approximately 25 wt% of the adhesive. The basis weight of the mat is approximately 88 g / m². 2 .

[0284] In another exemplary embodiment, the nonwoven mat comprises a first fiber having an average diameter in the range of about 10 μm and an average processing length of about 10 mm; a second fiber having an average diameter of about 3.5 μm and an average processing length in the range of 1 mm to 6 mm; and a UF / acrylic adhesive. In this embodiment, based on the weight of the glass fibers in the mat, the mat comprises about 90 wt% of the first fiber and about 10 wt% of the second fiber. Additionally, based on the weight of the mat, the mat comprises about 25 wt% of the adhesive. The basis weight of the mat is about 70 g / m². 2 .

[0285] In some exemplary embodiments, the microfibers undergo pretreatment before being introduced into the mixing tank (along with other fibers) of the wet web forming process. Pretreatment can be used to convert the fibers from a stored (e.g., compressed) form to a form more suitable for wet web forming, to adjust the fibers (e.g., to promote dispersibility) for wet web forming, to assess fiber defects (e.g., to remove fibrous material or potential fibrous material), etc.

[0286] To illustrate, the reference Figure 9 Figure 900 illustrates a pretreatment associated with the production of nonwoven yarns via a wet-laid process involving the blending of microfibers (e.g., the swirling fibers of the present invention) with wet-laid chopped strands (WUCS) of glass. In this example, the swirling fibers of the present invention are ultimately blended with WUCS in a slurry, wherein the percentage of microfibers in the total glass fiber blend can vary between 1 wt% and 99 wt%. Prior to using this blend of two glass-based fibers in the wet-laid process to produce the nonwoven yarn, the microfibers are wetted and dispersed in a separate process before being blended with the WUCS.

[0287] In the first step 902, a certain amount of microfibers is loaded onto the conveyor to feed into the mixing tank.

[0288] In the next step 904, the microfibers are fed into a mixing tank containing an aqueous solution of surfactants, viscosity modifiers, polymer binders, and other process chemical additives. The microfibers are added gradually to the mixing tank to ensure that each individual fiber is wetted by the aqueous solution. The shape of the agitator and tank is designed to provide sufficient shear energy input and volumetric displacement rate while also disrupting any continuous eddies that may form. The microfibers, with their large surface area to mass ratio, are thoroughly wetted by the aqueous solution. The dosage level of the microfibers in the mixing tank varies between 5 g / L and 50 g / L.

[0289] In the next step 906, after sufficient dispersion, the microfiber aqueous suspension is pumped through a screening unit to remove any potentially large impurities from the raw material. The screening device can be modified according to the required fineness of the microfiber suspension.

[0290] Microfibers may comprise agglomerates of fibers that are difficult to thoroughly wet and disperse using the initial mixing method (step 904). These agglomerates can manifest as defects in nonwoven mats (e.g., “flocs”). Therefore, in the next (optional) step 908, a device such as a high-shear mixer can be employed to break up these fiber flocs. In the high-shear mixer, the microfiber suspension passes through a slotted rotor / stator system that homogenizes the fiber suspension, thereby facilitating the breaking up of the fiber flocs.

[0291] Finally, in step 910, the pretreated microfibers are delivered to the mixing tank of the wet web forming process, where the microfibers can be more effectively dispersed together with other fibers in the white aqueous solution.

[0292] In view of the above, in one method of the present invention for producing nonwoven mats using a fiber blend comprising microfibers (wherein the percentage of microfibers in the total glass fiber blend can vary between 1 wt% and 99 wt%), the method includes dispersing the microfibers in a first white aqueous solution and then adding the dispersed microfibers to a second white aqueous solution containing non-rotating fibers. In some exemplary embodiments, the non-rotating fibers are WUCS fibers. In some exemplary embodiments, the non-rotating fibers have a larger average fiber diameter than the microfibers.

[0293] In some exemplary embodiments, separate aqueous mixtures of a first group of glass fibers and a second group of glass fibers are prepared and then combined under stirring (e.g., high-intensity mixing) to provide a homogeneous or nearly homogeneous dispersion of the fiber blend.

[0294] In some exemplary embodiments, a first group of glass fibers and a second group of glass fibers are combined to form a dry mixture of glass fibers. The dry mixture is then formed into an aqueous mixture under stirring (e.g., high-intensity mixing) to provide a homogeneous or substantially homogeneous dispersion of the fiber blend.

[0295] Because microfibers (e.g., made by method 300 or conventional methods) can be substantially free of or have significantly reduced amounts of any unfibered or poorly fiberized material (often referred to as “slag balls”), fused fibers, agglomerated fibers (e.g., flocculents), and / or other forms of defective fibers, as described above, nonwoven mats made of microfibers (e.g., the rotating fibers of the present invention) (e.g., nonwoven mats including portion 610) can also have fewer defects and thus have improved properties (e.g., surface smoothness, surface appearance).

[0296] For example, the nonwoven mat has a first surface 712 and a second surface (not shown) opposite to the first surface 712. In some exemplary embodiments, at least one surface of the nonwoven mat has less than about 100 fuzz particles per 1,000 m³. 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 100 fibrous particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, at least one surface of the nonwoven mat has less than about 50 fibrous particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 50 fuzz particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, at least one surface of the nonwoven mat has less than about 25 flocs / 1,000 m². 2Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 25 fibrous particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, at least one surface of the nonwoven mat has less than about 15 flocculent particles per 1,000 m². 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat has less than about 15 flocs / 1,000 m². 2 Nonwoven mat.

[0297] In some exemplary embodiments, at least one surface of the nonwoven mat is substantially free of any fibrous material / 1,000 m 2 Nonwoven mat. In some exemplary embodiments, each surface of the nonwoven mat is substantially free of any lint / 1,000 m². 2 Nonwoven mat.

[0298] One method for assessing or otherwise estimating the amount of fibrous material in a nonwoven mat is (1) unrolling a roll of the nonwoven mat, which represents approximately 500 m... 2 (1) the total surface area, (2) manually counting the mass of loosely aggregated fibers visible to the naked eye under standard or ambient lighting, and (3) converting (extrapolating) the counting results to a larger surface area (e.g., 1,000 m²). 2 The amount of flocculent material in a given surface area can be calculated. Other suitable methods for counting the amount of flocculent material in a given surface area are also conceivable. For example, image processing techniques can be used to generate the amount of flocculent material corresponding to relatively large portions of a nonwoven mat (e.g., ≥ 500 m²). 2 The image is then automatically evaluated to identify examples of fibrous material within it. Generally, smaller portions (e.g., < 500 m²) of the nonwoven mat material are identified for evaluation. 2 This produces less reliable estimates of flocculent counts, likely because the flocculent material is typically distributed over a larger portion of the resulting pad (roll).

[0299] Generally, nonwoven mats are designed to have sufficient strength to withstand the processing steps and speeds required to produce nonwoven mats for a variety of end uses. Furthermore, the strength of the nonwoven mat must be sufficient to allow it to be stored in any desired form and potentially for extended periods without loss of its cohesive properties. In some exemplary embodiments, the improved fiber diameter and / or fiber length distribution of the rotating fibers of the present invention is contemplated to enhance the structure and homogeneity or uniformity of the glass fiber arrangement in the nonwoven mat, which should result in more consistent and defined strength properties of the mat.

[0300] Exemplary Applications

[0301] Nonwoven fiber mats produced using the microfibers described herein (e.g., the rotating fibers of the present invention) have numerous applications. In general, the nonwoven mats of the present invention can prove suitable as a replacement for conventional nonwoven fiber mats, and as a replacement for other reinforcing materials (e.g., gun roving materials), fibers, or other reinforcing materials in a wide range of applications. For example, conventional nonwoven mats can be replaced by nonwoven mats of the present invention where improved properties (e.g., surface smoothness, mechanical strength) are required. Examples of potential uses include, but are not limited to, roofing materials (e.g., roof panels), surface yarns for composite materials, ceiling tiles, building panels, filter media, flooring applications, wall covering materials, and battery separators.

[0302] One such application is as a finish (“finishing”) for panels, such as wall panels. This finish is designed to be bonded to or otherwise joined to a core substrate (e.g., gypsum board, polyisocyanurate board, mineral wool insulation) to form the wall panel. Once formed, the wall panel can then undergo further processing (e.g., installation, painting).

[0303] Wall panels, such as gypsum or foam composite panel panels, are used in building structures to form partitions or walls for rooms, corridors, ceilings, etc. See, for example, US 2022 / 0380975, the entire disclosure of which is incorporated herein by reference. Similar panels are also used in exterior wall or roofing structures, such as cladding or roofing panels. Such composite panels may include front or back pads, such as fiberglass or other woven or nonwoven pads, on one or both sides to enhance the panel's performance properties, such as strength, rigidity, weather resistance, and moisture or mildew resistance. Such woven or nonwoven pads may be manufactured concurrently with the wall panel or separately from the wall panel.

[0304] Conventional nonwoven mats typically have a porous structure, causing materials applied to them, specifically liquid materials, to tend to leak from one surface to the opposite surface. This "leakage" problem is well known in the art. Various solutions have been attempted to combat undesirable penetration, including the use of coatings applied to the nonwoven mat.

[0305] Lightweight products that effectively seal the barrier between the environment and the underlying plate are desirable. Conventional coating compositions comprise a variety of formulations that typically include inorganic mineral pigments, organic binders, and fillers, including calcium carbonate, dixie clay, and so on. These minerals are usually combined with polymeric binders such as acrylics. Such coating compositions can be used to prevent leakage. Furthermore, when applied using conventional methods, including on-board and roller-on methods, a much higher coating weight is required to significantly improve the Gurley porosity of the barrier.

[0306] As described above, wallboards containing gypsum or polyisocyanurate (polyiso) in their cores typically face a nonwoven fiber mat. These facings require a relatively low air permeability (i.e., a relatively high Gurley value) to prevent leakage of the gypsum slurry or polyiso foam from the facing before it has fully cured. If gypsum / polyiso is allowed to leak from the facing, it can lead to various problems such as processing challenges (e.g., contamination of rollers), aesthetic challenges (e.g., leakage residues, spotting), etc.

[0307] Conventionally, to achieve a sufficiently low air permeability, an uncoated (precursor) nonwoven mat is coated with a thick coating. Generally speaking, the coating add-on weight can be used to describe coating differences. For conventional coatings, the coating add-on weight is in the range of about 200 g / m 2 to about 350 g / m 2 The thickness of the coated facing is typically in the range of about 0.8 mm to about 1.0 mm.

[0308] In many cases, due to the coating being pushed into the mat by a knife or coating process, the thickness of the coated mat is the same as or thinner than the original uncoated mat. Thus, a 10% reduction in mat thickness will result in a reduction of about 10% in the coating add-on amount required to fill the same 30% volume of the mat. For example, as Figure 10 illustrated in FIG. 1000, a conventional coated facing 1010 is formed from a precursor mat having a thickness of x1, where a typical coating thickness y1 is pushed into the mat (or otherwise impregnates the mat) to a depth of about 30% of x1 (thus y1 = 0.3x1). In contrast, as described herein, the coated facing 1020 of the present invention is formed from a precursor mat having a thickness of x2, where x2 < x1. For the facing 1020 of the present invention, the coating thickness y2 (where y2 < y1) is sufficient to fill about 30% of the same proportion of x2 (thus y2 < 0.3x1). This ability to reduce the necessary coating weight is advantageous because a higher coating weight requires more raw materials (and thus higher costs), longer drying times (and thus lower production volumes), and thicker coated facings (and thus less material in a fixed package - roll). Other unexpected results / beneficial effects are also described herein, such as the ability to reduce the coating weight (e.g., reduce by up to about 28%) and still achieve the same Gurley value.

[0309] The wall panel finish is formed from a nonwoven mat, which may be referred to as a "precursor mat" or "base mat." In some exemplary embodiments, the nonwoven mat is made by a wet web-forming process. Typically, the precursor mat is coated or impregnated with an inorganic filler (e.g., calcium carbonate (CaCO3) alumina trihydrate (ATH)) and a second binder (e.g., urea-formaldehyde, acrylic) to form a "coated mat" or "impregnated mat." The selection and application of the filler are controlled to achieve desired aesthetic properties (e.g., color, smoothness) and / or performance properties (e.g., porosity, tensile strength).

[0310] In various exemplary embodiments, a precursor pad is formed using microfibers (such as the rotating fibers of the present invention described herein). In some exemplary embodiments, a blend of WUCS glass fibers (as the first fiber) and microfibers in the form of rotating glass fibers (as the second fiber) is used to form the precursor pad. In some exemplary embodiments, the precursor felt comprises 1% to 99% by weight of microfibers (based on the weight of glass fibers in the felt). In some exemplary embodiments, the precursor felt comprises 10% to 90% by weight of microfibers (based on the weight of glass fibers in the felt). In some exemplary embodiments, the precursor pad comprises 25% to 75% by weight of microfibers (based on the weight of glass fibers in the pad). In some exemplary embodiments, the precursor pad comprises at least 10% by weight of microfibers (based on the weight of glass fibers in the pad). In some exemplary embodiments, the precursor pad comprises at least about 2.0% to about 15% by weight of microfibers (based on the weight of glass fibers in the pad).

[0311] Generally, the average diameter of the second fiber is smaller than that of the first fiber, and the average (processed, e.g., ground) length of the second fiber is smaller than that of the first fiber (processed, e.g., chopped) length. Furthermore, as described herein, the average fiber diameter distribution and / or average fiber length distribution of the rotating fibers of the present invention are more compact (by volume) around the target fiber diameter and / or target fiber length than those of conventional rotating fibers.

[0312] Initial experiments investigated the impact of using smaller diameter fibers (in nonwoven mats) on leakage problems.

[0313] To support this experiment, as shown in Table 8, a first sample nonwoven mat was formed using 10% by weight (based on the weight of glass fiber) of the present invention's rotating fiber with an average fiber diameter of 3.5 μm and a target length between 2 mm and 6 mm, 45% by weight (based on the weight of glass fiber) of WUCS fiber with an average fiber diameter of 11 μm and an average length of 6 mm, and 45% by weight (based on the weight of glass fiber) of WUCS fiber with an average fiber diameter of 13 μm and an average length of 19 mm. The fibers were held together by an adhesive system with a 25% LOI, resulting in a basis weight of 88 g / m². 2 The mat, in which the adhesive system generally comprises 90% urea-formaldehyde (UF) adhesive and 10% acrylic adhesive, was used. Similarly, a first control nonwoven mat was formed using 50% by weight (based on the weight of glass fiber) of WUCS fibers with an average fiber diameter of 11 μm and an average length of 6 mm, and 50% by weight (based on the weight of glass fiber) of WUCS fibers with an average fiber diameter of 13 μm and an average length of 19 mm. The fibers were held together by the adhesive system with a 25% LOI, resulting in a basis weight of 88 g / m². 2 The pads, the adhesive system generally comprises 90% urea-formaldehyde (UF) adhesive and 10% acrylic adhesive. Therefore, the first sample pad and the first control pad differ only in their respective fiber dimensions. Both the first sample pad and the first control pad are coated with the same conventional coating (i.e., a scraping formulation), which typically comprises, in the order of addition: (1) a diluent (0.00%); (2) a dispersant (0.1000%); (3) filler 1 (94.00%); (4) an acrylic adhesive (5.70%); (5) a biocide (0.0600%); and (6) a rheology modifier (0.1400%), for a target dry weight percentage of 100% and a dilution solids target of 68%. In addition to this exemplary coating formulation, the general concept of the invention is intended to encompass other coating formulations and application methods.

[0314]

[0315] Table 8

[0316] Additionally, as shown in Table 8, a second sample nonwoven mat was formed using 10% by weight (based on the weight of glass fiber) of the present invention's rotating fibers with an average fiber diameter of 3.5 μm and a target length of 2 mm-6 mm, and 90% by weight (based on the weight of glass fiber) of WUCS fibers with an average fiber diameter of 10 μm and an average length of 10 mm. The fibers were held together by an adhesive system with a 25% LOI, resulting in a basis weight of 70 g / m². 2The mat, in this adhesive system, generally comprises 90% urea-formaldehyde (UF) adhesive and 10% acrylic adhesive. Similarly, a second control nonwoven mat was formed using 100% by weight (based on the weight of glass fiber) of WUCS fibers with an average fiber diameter of 10 μm and an average length of 10 mm, wherein the fibers are held together by the adhesive system with a 25% LOI, resulting in a basis weight of 70 g / m². 2 The pads, the adhesive system generally comprising 90% urea-formaldehyde (UF) binder and 10% acrylic binder. Therefore, the first sample pad and the first control pad differ only in their respective fiber dimensions. Both the second sample pad and the second control pad are coated with the same conventional coating (i.e., a scraping formulation), which typically comprises, in the order of addition: (1) a diluent (0.00%); (2) a dispersant (0.1000%); (3) filler 1 (94.00%); (4) an acrylic binder (5.70%); (5) a biocide (0.0600%); and (6) a rheology modifier (0.1400%), for a target dry weight percentage of 100% and a dilution solids target of 68%. In addition to this exemplary coating formulation, the general concept of the invention is intended to encompass other coating formulations and application methods.

[0317] It demonstrates that using the rotating fibers of this invention enables the production of thinner mats (at a given basis weight). For example, the thickness of a first control mat (Control 1) was measured at ten different locations on the mat according to the ASTM D1777 standard test method for determining the thickness of textile materials, in order to generate... Figure 11A The data points are shown in graph 1100. From this data, the average thickness of the first control pad was determined to be 0.905 mm. Similarly, the thickness of the first sample pad (sample 1) was measured at ten different locations on the pad according to the ASTM D1777 standard test method to generate the data points shown in graph 1100. Based on this data, the average thickness of the first sample pad was determined to be 0.824 mm, which is statistically significantly reduced compared to the first control pad.

[0318] It is also shown that using the rotating fibers of the present invention to produce thinner mats (at a given basis weight) does not result in a decrease in normalized tensile properties. For example, according to the TAPPI T 1009 om-10 standard test method, using a 5.0 cm × 25.4 cm sample for determining the tensile strength and elongation at break of glass fiber mats, the tensile properties of a first control mat (Control 1) were measured at ten different locations on the mat to produce… Figure 11B The data points are shown in graph 1150. Based on this data, the average normalized tensile properties (longitudinal) of the first control pad were determined to be 4.19 N / g / m. 2Similarly, according to the TAPPI T 1009 om-10 standard test method, using a 5.0cm × 25.4cm sample, the tensile properties of the first sample pad (sample 1) were measured at ten different locations on the pad to generate the data points shown in graph 1150. From this data, the average normalized tensile property (longitudinal) of the first sample pad was determined to be 4.19 N / g / m. 2 There was no statistically significant difference in the average normalized tensile properties between the pad and the first control pad.

[0319] Therefore, compared to similar wall panel finishes made without the rotating fibers of the present invention, incorporating a certain amount of the rotating fibers of the present invention into a nonwoven mat (precursor mat) and then coating / impregnating it to form a coated glass finish demonstrates the production of a wall panel finish with reduced thickness for a given basis weight. Furthermore, the thinner wall panel finish exhibits comparable tensile properties compared to a thicker wall panel finish made without the rotating fibers of the present invention.

[0320] In this way, more improved (i.e. thinner) coated glass cladding suitable for use as wall panel cladding can be stored on rollers of predetermined size, compared to conventional (i.e., thicker) coated glass cladding.

[0321] In the tests, the Gurley air resistance of the sample was analyzed by adding weight relative to the coating. This is particularly important for wall panels that include a gypsum core, as such wall panels require finishes that meet both a minimum and a maximum Gurley value (i.e., the target Gurley range) to be effective. In other words, if the air permeability is too high (i.e., too low a Gurley value), leakage may occur; conversely, if the air permeability is too low (i.e., too high a Gurley value), moisture cannot escape from the core as the gypsum solidifies / hardens, which may lead to blistering. For example, the target Gurley range may include a range of Gurley values ​​between 20s and 150s. Different users / customers may require finishes to meet different target Gurley ranges based on their manufacturing processes, gypsum compositions, etc.

[0322] It is known that Gurley permeability is significantly affected by coating weight. However, it has been found that coated glass finishes formed from precursor pads including the rotating fibers of the present invention exhibit a more robust Gurley response (for the same coating weight) compared to conventional coated glass finishes that do not include the rotating fibers of the present invention. This more robust Gurley response can also be considered as reduced Gurley variability.

[0323] For example, according to the TAPPI T460 standard test method used to determine the air permeability of paper, film, foil and other materials, the air permeability of a first control pad (control 1) is measured to produce... Figure 12The data points shown in graph 1200 represent a value between 110 g / m³. 2 and 150g / m 2 The coating weight was averaged from six Gurley readings on individually coated sheets. From this data, it was observed that the coating weight added to the first control pad (Control 1) was approximately 116 g / m². 2 Change to approximately 141 g / m 2 This caused the Gurley value of the pad to change from approximately 47 s to approximately 59 s. The Gurley response of Control 1 pad to the change in the weight added to its coating can be represented by the slope extending through the aforementioned data points, which in this case has a slope of approximately 0.49.

[0324] Similarly, the air permeability of the first sample pad (sample 1) was measured according to the TAPPI T460 standard test method used to determine the air permeability of paper, film, foil and other materials, in order to produce Figure 12 The data points shown in graph 1200 represent a value between 110 g / m³. 2 and 150g / m 2 The coating added weight was the average of six Gurley readings on individually coated sheets. From this data, it was observed that the coating added weight of the first sample pad (sample 1) was approximately 110 g / m². 2 Change to approximately 145g / m 2 This caused the Gurley value of the pad to change from approximately 71.2 s to approximately 72.6 s. The Gurley response of the sample 1 pad to the change in the weight added to its coating can be represented by the slope extending through the aforementioned data points, which in this case has a slope of approximately 0.04.

[0325] Therefore, compared to conventional coated glass finishes that do not include the rotating fibers of this invention, the coated glass finish including the rotating fibers of this invention (i.e., sample 1 pad) exhibits a statistically more robust Gurley response. In other words, the breathability of the coated glass finish of this invention is less sensitive to changes in coating weight compared to conventional coated glass finishes that do not include the rotating fibers of this invention.

[0326] As another example, the air permeability of a second control pad (Control 2) was measured according to the TAPPI T460 standard test method used to determine the air permeability of paper, film, foil, and other materials to produce... Figure 13 The data points shown in graph 1300 represent a value between 125 g / m³. 2 and 180g / m 2The coating weight was averaged from six Gurley readings on individually coated sheets. From this data, it was observed that the coating weight added to the second control pad (Control 2) was approximately 130 g / m². 2 Change to approximately 175g / m 2 This caused the Gurley value of the pad to change from approximately 57.5 s to approximately 185 s. The Gurley response of the control pad to the change in the weight added to its coating can be represented by the slope extending through the aforementioned data points, which in this case has a slope of approximately 2.82.

[0327] Similarly, the air permeability of the second sample pad (sample 2) was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil and other materials to produce... Figure 13 The data points shown in graph 1300 represent a value between 125 g / m³. 2 and 180g / m 2 The coating added weight was the average of six Gurley readings on the individually coated sheets. From this data, it was observed that the coating added weight of the second sample pad (sample 2) increased from approximately 130 g / m². 2 Change to approximately 175g / m 2 This caused the Gurley value of the pad to change from approximately 68 s to approximately 122 s. The Gurley response of the sample 2 pad to the change in the weight added to its coating can be represented by the slope extending through the aforementioned data points, which in this case has a slope of approximately 1.20.

[0328] Similarly, compared to conventional coated glass finishes that do not include the rotating fibers of this invention, the coated glass finish including the rotating fibers of this invention (i.e., sample 2 pad) exhibits a statistically more robust Gurley response. In other words, the breathability of the coated glass finish of this invention is less sensitive to changes in coating weight compared to conventional coated glass finishes that do not include the rotating fibers of this invention.

[0329] Therefore, compared to similar wall panel finishes made without the rotating fibers of this invention, incorporating a certain amount of the rotating fibers of this invention into a nonwoven pad (precursor pad) and then coating / impregnating to form a coated glass finish demonstrates a wall panel finish with a statistically more robust Gurley response. In other words, the permeability of the coated glass finish of this invention is less sensitive to variations in its coating weight compared to conventional coated glass finishes that do not include the rotating fibers of this invention. Due to its more robust Gurley response, the coated glass finish of this invention is able to achieve the target minimum or maximum Gurley value (and thus the target Gurley range) over a wider range of coating weights, which increases process and product flexibility and reduces the likelihood of missing the Gurley value required by the user or customer (i.e., reducing the likelihood of leakage).

[0330] This is particularly important for wall panels that include a gypsum core, as such panels require finishes that meet both a minimum and a maximum Gurley value (i.e., the target Gurley range) to be effective. In other words, if the permeability is too high (i.e., too low a Gurley value), leakage may occur; conversely, if the permeability is too low (i.e., too high a Gurley value), moisture cannot escape from the core as the gypsum solidifies / hardens, which may lead to blistering. For example, the target Gurley range may include a range of Gurley values ​​between 10s and 80s. Different users / customers may require finishes that meet different target Gurley ranges based on their manufacturing processes, gypsum compositions, etc.

[0331] also, Figure 12 Graph 1200 shows that the first sample pad (sample 1) achieved a significantly higher Gurley value compared to the first control pad (control 1) with the same added weight of coating. For example, when 130 g / m 2 When the coating was applied to the first sample pad (sample 1), a Gurley value of approximately 72 s was achieved. However, when a coating of 130 g / m was applied... 2 When the same coating was applied to the first control pad (Control 1), a lower Gurley value of approximately 54 s was achieved. Therefore, the coated glass finish of the present invention (represented by the data of Sample 1 in Graph 1200) can achieve a Gurley value comparable to that exhibited by the first control pad (represented by the data of Control 1) with significantly less coating (i.e., with a lower added weight).

[0332] same, Figure 13 The curve 1300 shows that, in some cases, the second sample pad (sample 2) achieved significantly higher Gurley values ​​compared to the second control pad (control 2) with the same added weight of coating. For example, when 130 g / m 2When the coating was applied to the second sample pad (sample 2), a Gurley value of approximately 68 s was achieved. However, when 130 g / m 2 When the same coating was applied to the second control pad (Control 2), a lower Gurley value of approximately 57.5 s was achieved. Therefore, the coated glass finish of the present invention (represented by the data for Sample 2 in Graph 1300) can achieve a comparable Gurley value to that shown by the second control pad (represented by the data for Control 2) with significantly less coating (i.e., with a lower added weight). However, as Figure 13 As shown in graph 1300, this trend occurs at approximately 137 g / m 2 The coating is reversed after the weight point is added. Similarly, this shows the more robust Gurley response values ​​exhibited by the pads of the present invention (e.g., Sample 1, Sample 2), since it is less likely that the target Gurley value will be missed when the pad is primed or topcoated.

[0333] Figure 14 Graph 1400 also illustrates the increased flexibility and potential beneficial effects of the coated glass finish of the present invention, specifically for use as a wall panel finish. Graph 1400 shows that the aforementioned robust Gurley response also allows for a reduction in the coating weight required to achieve sufficiently high Gurley values.

[0334] Here, the air permeability of a first control pad (Control 1) and a first sample pad (Sample 1) was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil and other materials to produce the data points shown in graph 1400, where each data point represents a coating added weight of between 140 g / m² for Control 1 pad. 2 and 180g / m 2 Between 10-12 individually coated sheets, one of which was coated with a coating of 110 g / m², and the other of the pads in sample 1 had a coating weight between 110 g / m². 2 and 140g / m 2 The average of six Gurley readings on one of 10-12 individually coated sheets. From this data, it was observed that approximately 160 g / m² was obtained. 2 The average coating weight, compared to pad 1, yielded an average Gurley value of approximately 56 s. Conversely, for approximately 123 g / m², the average coating weight was significantly lower. 2 With an average coating weight, Sample 1 pad obtained an average Gurley value of approximately 79 s. Therefore, compared to the first control pad (represented by Control 1 data), the coated glass finish of the present invention (represented by Sample 1 data) is able to achieve a higher Gurley value with a significantly less coating weight. More specifically, Sample 1 pad obtained a higher Gurley value (i.e., 79 s) than Control 1 pad (i.e., 56 s), although compared to Control 1 pad (i.e., 160 g / m²), it also achieved a higher Gurley value.2 Compared to the previous method, the coating weight was reduced by approximately 25% (i.e., 123 g / m²). 2 ).

[0335] When analyzed from the perspective of achieving the same target Gurley value (60s in this case), the data shown in graph 1400 indicates that the coated glass finish of the present invention (represented by the data of Sample 1) requires only 116 g / m² of coating weight to achieve the target Gurley value, while the first control pad (represented by the data of Control 1) requires 162 g / m² of coating weight to achieve the target Gurley value. By requiring approximately 28% less coating weight to achieve the target Gurley value, the coated glass finish of the present invention (Sample 1) represents a significant improvement in finish materials (e.g., wall panel finishes), providing potentially beneficial effects such as increased production volume and reduced costs.

[0336] In view of the above, the use of microfibers (e.g., the rotating fibers of the present invention) in the precursor pad can result in improved coated glass finishes, which are suitable for use as finishing materials for wall panels (e.g., gypsum board, polyisocyanurate board). By way of example, improved coated glass finishes can be thinner than conventional coated glass finishes (for the same coating weight); improved coated glass finishes can exhibit a more robust Gurley response to coating weight additions compared to conventional coated glass finishes; improved coated glass finishes can achieve higher Gurley values ​​at the same coating weight additions compared to conventional coated glass finishes; and / or improved coated glass finishes can achieve comparable Gurley values ​​at lower coating weight additions compared to conventional coated glass finishes.

[0337] In addition to the rotating fiber of the present invention, the precursor pad made from the fiber, and the coated glass finish made from the precursor pad, the role of the coating composition in influencing air permeability (Gurley properties) was also explored.

[0338] As described above, the precursor pad is coated or impregnated with an inorganic filler (e.g., calcium carbonate (CaCO3) or alumina trihydrate (ATH)) and a second binder (e.g., urea-formaldehyde, acrylic acid) to form a coated glass finish. Calcium carbonate is a common filler used in such coating compositions due to its white color, general availability, and relatively low cost. However, the effect of blended fillers on permeability was explored because different sources of calcium carbonate with varying particle sizes are available.

[0339] Here, blended fillers can refer to different materials with different particle size distributions or the same material with different particle size distributions.

[0340] For example, as shown in Table 9, commercially available first calcium carbonate filler (CaCo3-1) and commercially available second calcium carbonate filler (CaCo3-2) have different particle size distributions. Specifically, the CaCo3-1 material has a median diameter (D) of 2.9. 50 The particle size distribution is represented by ), and the CaCo3-1 material has a median diameter (D) of 16.3. 50 The particle size distribution is represented by ). Similarly, equal-part blends of CaCo3-1 and CaCo3-2 materials will have different particle size distributions. As shown in Table 9, a 50%:50% blend of CaCo3-1 and CaCo3-2 materials (dry weight percentage of total filler, excluding additives / binders) has a median diameter (D) of 5.1. 50 The particle size distribution is represented by ).

[0341]

[0342] Table 9

[0343] The designation D# y (or d# y) typically indicates that the percentage of particles in the material that are less than the provided diameter y, and the percentage of particles in the material that are greater than the provided diameter y. Therefore, D 50 This is often referred to as the median diameter of the particle size distribution, because half of the particles will be smaller than the given D. 50 The value, and half of the particles will be larger than the provided D. 50 value.

[0344] Without being bound by theory, it is believed that coatings containing filler blends can stack better by using blends of filler materials with different particle size distributions, because smaller filler particles will be able to occupy the voids between larger filler particles, such as... Figure 15 As shown. Therefore, improved coatings containing the selected filler blends can result in higher Gurley values, which in turn can reduce the required coating weight. Furthermore, improved coatings containing the selected filler blends can result in reduced coating penetration into the pad, thereby providing a more consistent / uniform coating. In addition, the use of filler blends can alter the rheological properties of the coating, allowing for better coating of smaller diameter fibers (e.g., the rotating fibers of the present invention). Furthermore, the use of filler blends can reduce the amount of binder required in the coating, for example, by about 10% to about 15%.

[0345] Furthermore, a bimodal filler diameter distribution can provide aesthetic improvements. For example, a larger filler component reduces light scattering, thus allowing for a reduction in the pigment load necessary to achieve the desired color (non-white) properties. In some exemplary embodiments, a coating composition containing a blend of fillers (e.g., a blend of CaCO3-1 and CaCO3-2) may require approximately 20% to approximately 55% less pigment than a similar coating composition containing only a single, smaller filler (e.g., CaCO3-1). Due to the lower pigment load, a corresponding reduction in spots is expected in the colored coated glass surface.

[0346] While blend fillers generally help increase Gurley values, it has been unexpectedly found that using blend fillers to coat nonwoven mats made from fiber blends containing microfibers (such as the rotating fibers of the present invention) can achieve a significantly increased Gurley value.

[0347] For example, adding 245 g / m² of weight to the same target coating. 2 and 220g / m 2 Up to 290g / m 2 The coating was added within a certain weight range, and both the first control pad and the first sample pad were coated with the same coating composition containing a single filler (i.e., CaCO3-1 calcium carbonate material) to produce a first control coated finish (Control 1) and a first sample coated finish (Sample 1), respectively. The air permeability of the Control 1 coated finish was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil, and other materials to produce… Figure 16 The first set (leftmost) of the data points shown in graph 1600, where each data point represents the average Gurley permeability (Tappi T460) divided by g / m 2 Add weight to the unit of coating. Control 1, with its coated finish, shows a normalized Gurley value of 0.21. Similarly, the air permeability of Sample 1 with its coated finish was measured according to the Tappi T460 standard test method for determining the air permeability of paper, film, foil, and other materials, to produce a second set of data points as shown in graph 1600, where each data point represents the average Gurley air permeability (Tappi T460) divided by g / m³. 2 Add weight to the unit coating. Sample 1, with the coated finish, shows a normalized Gurley value of 0.27. When compared, it has approximately 0.21 s / g / m 2 The first dataset has average normalized Gurley values ​​of approximately 0.27 s / 2 / m. 2In the second dataset of average normalized Gurley values, the Gurley values ​​obtained from the coated finish of Sample 1 (containing the rotating fibers of the present invention) did not show a significant increase compared to the coated finish of Control 1 (without the rotating fibers of the present invention). Typically, ≥0.08s / g / m 2 An increase in will be considered a significant increase.

[0348] Next, add 245 g / m² of the same target coating. 2 and 220g / m 2 Up to 290g / m 2 The coating weight range was increased by coating both the first control pad and the first sample pad with the same coating composition, which contained a filler blend made of smaller particles of calcium carbonate material (i.e., CaCO3-1 material) and larger particles of calcium carbonate material (i.e., CaCO3-2 material), to produce a first control coated finish (Control 1 - Filler Blend) and a first sample coated finish (Sample 1 - Filler Blend), respectively. The air permeability of the finish coated with Control 1 - Filler Blend was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil, and other materials to produce… Figure 16 The third set of data points shown in graph 1600, where each base data point represents the average Gurley permeability (Tappi T460) divided by g / m 2 Add weight to the unit coating. The normalized Gurley value for the finish coated with the filler blend of control 1 is 0.64. Similarly, the air permeability of the finish coated with the filler blend of sample 1 was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil and other materials to produce the fourth set (rightmost) of data points shown in graph 1600, where each data point represents the average Gurley air permeability (Tappi T460) divided by g / m 2 Add weight per unit coating. The finish coated with Sample 1 – filler blend – showed a normalized Gurley value of 1.68. When compared, it has approximately 0.64 S / g / m 2 The third dataset has average normalized Gurley values ​​of approximately 1.68 s / g / m 2 When averaging the normalized Gurley values ​​for the fourth dataset, statistically significant differences were observed in the resulting Gurley values. This increase in magnitude was unexpected, as the proportional difference between the third and fourth datasets was expected to be similar to the proportional difference seen between the first and second datasets.

[0349] Based on the data observed in graph 1600, it was found that the precursor pad, comprising a portion of the rotating fiber of the present invention, provides an unexpected and improved interaction with the coating containing the blended filler. Therefore, very high Gurley values ​​(e.g., greater than 400 s) can be achieved, which is advantageous for applications requiring higher Gurley values ​​(such as polyisocyanurate wall panels). Furthermore, the synergistic effect between the precursor pad and the blended filler of the present invention allows for reduced coating weight when a lower Gurley value would be sufficient.

[0350] As an additional evaluation, the air permeability (Gurley value) of the nonwoven mat of the present invention coated with four different filler compositions was measured. Specifically, the air permeability was measured at 245 g / m². 2 The target coating adds weight and 220g / m 2 Up to 290g / m 2 The coating was added within a certain weight range, and a first sample of the pad was coated with a coating composition containing a single filler (i.e., CaCO3-1 calcium carbonate material) to produce a finish coated with the first sample (Sample 1). The air permeability of the finish coated with Sample 1 was measured according to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil, and other materials, expressed as the average Gurley air permeability (Tappi T460) divided by g / m³. 2 The coating added weight was calculated. The finish coated with Sample 1 showed an average normalized Gurley value of approximately 0.27 s / g / m. 2 For comparison, three additional samples (i.e., samples 2, 3, and 4) with the coated finish were prepared in the same manner as Sample 1, but using different filler blends (i.e., blends of CaCO3-1 and CaCO3-2). Specifically, the filler used in Sample 2 consisted of 75% CaCO3-1 and 25% CaCO3-2; the filler used in Sample 3 consisted of 50% CaCO3-1 and 50% CaCO3-2; and the filler used in Sample 4 consisted of 25% CaCO3-1 and 75% CaCO3-2. The permeability of Samples 2, 3, and 4 was measured in the same manner as Sample 1, wherein the average normalized Gurley value of each of Samples 2, 3, and 4 was greater than the average normalized Gurley value exhibited by Sample 1.

[0351] In another evaluation, the air permeability (Gurley value) of four different nonwoven mats was measured, each coated with the same blended (i.e., 50% CaCO3-1 and 50% CaCO3-2) filler composition. Specifically, a first control nonwoven mat (control) was formed using 50% by weight (by weight of glass fiber) of WUCS fibers with an average fiber diameter of 11 μm and an average length of 6 mm and 50% by weight (by weight of glass fiber) of WUCS fibers with an average fiber diameter of 13 μm and an average length of 19 mm. The fibers were held together with a 25% LOI by an adhesive system generally comprising 90% urea-formaldehyde (UF) binder and 10% acrylic binder to produce a basis weight of 88 g / m³. 2 The mat was constructed using 10% by weight (by weight of glass fiber) of the present invention's rotating fibers with an average fiber diameter of 3.5 μm and a target length between 2 mm and 6 mm, 45% by weight (by weight of glass fiber) of WUCS fibers with an average fiber diameter of 11 μm and an average length of 6 mm, and 45% by weight (by weight of glass fiber) of WUCS fibers with an average fiber diameter of 13 μm and an average length of 19 mm, to form a first sample nonwoven mat (sample 1). The fibers were held together with a 25% LOI by an adhesive system generally comprising 90% urea-formaldehyde (UF) binder and 10% acrylic binder to produce a basis weight of 88 g / m³. 2 The control pad and sample 1 pad differ only in their respective fiber sizes. A second sample nonwoven pad (sample 2) was formed similarly to sample 1 pad, but with 10% by weight (by weight of glass fiber) of 3.5 μm non-rotating (i.e., WUCS) microfibers replacing 10% by weight (by weight of glass fiber) of the 3.5 μm rotating microfibers of the present invention. These non-rotating (composite) fibers were drawn through the perforated plate of the stencil and chopped to the desired length. Finally, a third sample nonwoven pad (sample 3) was formed similarly to sample 1 pad, but with 10% by weight (by weight of glass fiber) of 3.5 μm conventional rotating microfibers replacing 10% by weight (by weight of glass fiber) of the 3.5 μm rotating microfibers of the present invention (see [reference]). Figure 2C According to the TAPPI T460 standard test method for determining the air permeability of paper, film, foil and other materials, the air permeability of four samples (i.e., control, sample 1, sample 2 and sample 3) was measured, which is expressed as the average Gurley air permeability (Tappi T460) divided by g / m³. 2 The coating added weight was calculated. The mean normalized Gurley value of each of the microfiber-containing pads (i.e., Sample 1, Sample 2, and Sample 3) was significantly greater than that shown by the control pad.

[0352] In view of the above, the general concept of the present invention includes a coating composition that comprises a blended filler and a binder. The coating composition may include other components / additives, such as colored pigments, dispersants, defoamers, biocides, rheology modifiers, etc. The coating composition is suitable for coating or impregnating non-woven mats, such as precursor mats that include a portion of microfibers (e.g., the spun fibers of the present invention described herein). The coated mat (e.g., the coated glass finish) can be used as a finish material on wall panels.

[0353] In some exemplary embodiments, the binder is an acrylic binder. In other exemplary embodiments, the binder can be selected from emulsions, suspensions, and polymer dispersions, such as styrene acrylics, polyvinyl alcohol, polyolefins, polyolefin copolymers, polyvinyl acetate, butadiene styrene, and combinations thereof.

[0354] In some exemplary embodiments, the blended filler comprises a first calcium carbonate material (ccm-1) having a first median particle size (mps-1) and a second calcium carbonate material (ccm-2) having a second median particle size (mps-2), where mps-1 ≠ mps-2 (where mps-1 < mps-2). In some exemplary embodiments, the ratio of the smaller mps-1 to the larger mps-2 is at least 1:3. In some exemplary embodiments, the ratio of mps-1 to mps-2 is at least 1:4. In some exemplary embodiments, the ratio of mps-1 to mps-2 is at least 1:5. In some exemplary embodiments, the ratio of mps-1 to mps-2 is at least 1:6. In some exemplary embodiments, the ratio of mps-1 to mps-2 is in the range of 1:2 to 1:20.

[0355] In some exemplary embodiments, the blended filler includes a mineral filler component in addition to calcium carbonate.

[0356] As described above, a common application of the precursor mats of the present invention and the coated / impregnated mats formed therefrom is wall panel finishing. In view of the general inventive concept described herein, the wall panel finishes of the present invention can have a reduced thickness (without sacrificing tensile properties), can have a reduced coating weight, can have an increased Gurley value, and / or can have a reduced Gurley variability.

[0357] In some embodiments, various inventive concepts can be utilized in combination with each other. Furthermore, any specific ingredient described in a particular disclosed embodiment should be understood to be applicable to all disclosed embodiments unless the introduction of such a specific ingredient would contradict the terminology expressed in that embodiment. The scope of the general inventive concept presented herein is not intended to be limited to the specific exemplary embodiments shown and described herein. Based on the given disclosure, those skilled in the art will not only understand the general inventive concept and its accompanying advantages, but will also discover various obvious changes and modifications thereto. For example, although exemplary embodiments generally disclose the use of glass fibers, the general inventive concept may cover fibers made of materials other than glass, such as mineral wool or asbestos. Therefore, it is sought to cover all such changes and modifications and any equivalents that fall within the spirit and scope of the general inventive concept described and / or claimed herein.

Claims

1. A coated or impregnated glass finish, said coated or impregnated glass finish comprising: Precursor pad, the precursor pad comprising a plurality of first fibers, a plurality of second fibers, and a main adhesive holding the first fibers and second fibers together in an alternating arrangement; and A coating composition comprising a first mineral filler, a second mineral filler, and a second binder. The first fiber has an average fiber diameter greater than approximately 8 μm; The second fiber has an average fiber diameter of less than approximately 5 μm; The first mineral filler has a first median particle size of less than approximately 4 μm; and The second mineral filler has a second median particle size greater than about 8 μm.

2. The coated or impregnated glass finish according to claim 1, wherein the second fiber has an average fiber diameter of less than about 4 µm x µm; The second fiber constitutes y% of the weight of the pad. Where y / x < 10.

3. The coated or impregnated glass finish according to claim 1, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 3.5 μm.

4. The coated or impregnated glass finish according to claim 1, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 3.0 μm.

5. The coated or impregnated glass finish according to claim 1, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 2.5 μm.

6. The coated or impregnated glass finish according to claim 1, wherein the primary adhesive comprises a urea-formaldehyde adhesive.

7. The coated or impregnated glass finish of claim 1, wherein the primary adhesive comprises an acrylic adhesive.

8. The coated or impregnated glass finish according to claim 1, wherein the first mineral filler is calcium carbonate.

9. The coated or impregnated glass finish according to claim 1, wherein the second mineral filler is calcium carbonate.

10. The coated or impregnated glass finish according to claim 1, wherein the ratio of the first median particle size to the second median particle size is at least 1:

3.

11. The coated or impregnated glass finish according to claim 1, wherein the ratio of the first median particle size to the second median particle size is at least 1:

4.

12. The coated or impregnated glass finish according to claim 1, wherein the ratio of the first median particle size to the second median particle size is at least 1:

5.

13. The coated or impregnated glass finish according to claim 1, wherein the ratio of the first median particle size to the second median particle size is at least 1:

6.

14. The coated or impregnated glass finish according to claim 1, wherein the ratio of the first median particle size to the second median particle size is in the range of 1:2 to 1:

20.

15. The coated or impregnated glass finish of claim 1, wherein the second adhesive comprises an acrylic adhesive.

16. A panel comprising a plaster core and a coated or impregnated glass finish according to any one of claims 1 to 15 on at least one side of the core.

17. A panel comprising a core of insulating material and a coated or impregnated glass finish on at least one side of the core according to any one of claims 1 to 15.

18. The board according to claim 17, wherein the thermal insulation material is polyisocyanurate foam.

19. A coated or impregnated glass finish, said coated or impregnated glass finish comprising: Precursor pad, the precursor pad comprising a plurality of first fibers, a plurality of second fibers, and a main adhesive holding the first fibers and second fibers together in an alternating arrangement; and A coating composition comprising a first mineral filler, a second mineral filler, and a second binder. The above The first fiber has an effective fiber diameter a; The second fiber has an effective fiber diameter b; Where b <a; The first mineral filler has a first median particle size of less than approximately 4 μm; and The second mineral filler has a second median particle size greater than about 8 μm.

20. The coated or impregnated glass finish according to claim 19, wherein a > 9 μm.

21. The coated or impregnated glass finish according to claim 19, wherein b < 9 μm.

22. The coated or impregnated glass finish of claim 19, wherein the second fiber has an average fiber diameter of less than about 9 µm x µm; The second fiber constitutes y% of the weight of the pad. Where y / x < 10.

23. The coated or impregnated glass finish of claim 19, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 3.5 μm.

24. The coated or impregnated glass finish of claim 19, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 3.0 μm.

25. The coated or impregnated glass finish of claim 19, wherein the second fiber has an average fiber diameter x of less than about 4 µm; and The fiber diameter distribution of the second fiber has a standard deviation from x of less than 2.5 μm.

26. The coated or impregnated glass finish of claim 19, wherein the primary adhesive comprises a urea-formaldehyde adhesive.

27. The coated or impregnated glass finish of claim 19, wherein the primary adhesive comprises an acrylic adhesive.

28. The coated or impregnated glass finish according to claim 19, wherein the first mineral filler is calcium carbonate.

29. The coated or impregnated glass finish of claim 19, wherein the second mineral filler is calcium carbonate.

30. The coated or impregnated glass finish of claim 19, wherein the ratio of the first median particle size to the second median particle size is at least 1:

3.

31. The coated or impregnated glass finish of claim 19, wherein the ratio of the first median particle size to the second median particle size is at least 1:

4.

32. The coated or impregnated glass finish of claim 19, wherein the ratio of the first median particle size to the second median particle size is at least 1:

5.

33. The coated or impregnated glass finish of claim 19, wherein the ratio of the first median particle size to the second median particle size is at least 1:

6.

34. The coated or impregnated glass finish of claim 19, wherein the ratio of the first median particle size to the second median particle size is in the range of 1:2 to 1:

20.

35. The coated or impregnated glass finish of claim 19, wherein the second adhesive comprises an acrylic adhesive.

36. A wall panel comprising a plaster core and a coated or impregnated glass finish according to any one of claims 19 to 35 on at least one side of the core.

37. A heat insulation panel comprising a core of heat insulation material and a coated or impregnated glass finish on at least one side of the core according to any one of claims 19 to 35.

38. The insulation panel according to claim 37, wherein the insulation material is polyisocyanurate foam.

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