Method of making coated mat online and coated mat products

Abstract

New coated nonwoven fibrous mats having properties particularly suited for a facer on gypsum wallboard and other substrates and in laminates of various types, and the method of making the coated mat is disclosed. The mat preferably contains a major portion of glass fibers and a minor portion of a resinous binder. The coating is preferably permeable and reduces fiber dust and abrasion experienced in the past with relatively coarse, relatively inexpensive glass fibers in the mat. Contrary to previous coating methods, the coated fibrous mat is made in-line on a wet mat forming production line by applying a wet foam binder onto a wet, fibrous web followed by drying and curing in-line.

We claim:  
     
         1 . In a method of making a coated fibrous mat on a wet process mat machine in which an aqueous slurry containing fibers is continuously deposited onto the top surface of a moving permeable forming belt, is partially dewatered and is dried to produce a dry nonwoven fibrous mat, the improvement comprising applying a foam onto the wet web after said web has been partially dewatered, the foam or froth having a high percentage of air and a density of below about 83.33 gms/liter, and applying said foam at a rate to produce a dry mat having a coating on one face.  
     
     
         2 . The method of  claim 1  wherein an aqueous binder is first applied to the wet, partially dewatered web before applying said foam.  
     
     
         3 . The method of  claim 1  wherein at least a majority of the fibers are glass fibers and said foam is selected and applied to produce a dry, coated mat having a permeability of at least about 0.37 CMM/square meter.  
     
     
         4 . The method of  claim 1  wherein said foam is selected and applied to produce a dry, coated mat having a permeability of at least about 0.9 CMM/sq. meter.  
     
     
         5 . The method of  claim 1  wherein said foam is selected and applied to produce a dry, coated mat having a permeability of at least about 1.5 CMM/sq. meter.  
     
     
         6 . The method of  claim 1  wherein the foam has a density in the range of about 33.3 and 66.7 grams/liter prior to being applied.  
     
     
         7 . The method of  claim 3  wherein the foam has a density in the range of about 33.3 and 66.7 grams/liter prior to being applied.  
     
     
         8 . The method of  claim 4  wherein the foam has a density in the range of about 33.3 and 66.7 grams/liter prior to being applied.  
     
     
         9 . The method of  claim 5  wherein the foam has a density in the range of about 33.3 and 66.7 grams/liter prior to being applied.  
     
     
         10 . The method of  claim 1  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 10 milliliters.  
     
     
         11 . The method of  claim 6  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 milliliters.  
     
     
         12 . The method of  claim 7  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 milliliters.  
     
     
         13 . The method of  claim 8  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 milliliters.  
     
     
         14 . The method of  claim 9  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 milliliters.  
     
     
         15 . The method of  claim 3  wherein the foam is such that when one liter of the foam is placed in an Imhoff cone and allowed to set for 10 minutes, the amount of liquid formed in the bottom of the Imhoff cone is less than about 10 milliliters.  
     
     
         16 . The method of  claim 1  wherein the foam is selected to have a good heat stability and does not completely collapse during drying and curing, leaving a foam coating on one surface of the mat.  
     
     
         17 . The method of  claim 2  wherein the foam is selected to have a good heat stability and does not completely collapse during drying and curing, leaving a foam coating on one surface of the mat.  
     
     
         18 . A permeable, coated, nonwoven fibrous mat made by the process described in  claim 1 .  
     
     
         19 . A permeable, coated, nonwoven fibrous mat made by the process described in  claim 2 .  
     
     
         20 . A permeable, coated, nonwoven fibrous mat made by the process described in  claim 3 .  
     
     
         21 . A permeable, foam coated, nonwoven fibrous mat made by the process described in  claim 5 .  
     
     
         22 . A permeable, foam coated, nonwoven fibrous mat made by the process described in  claim 6 .  
     
     
         23 . A permeable, foam coated, nonwoven fibrous mat made by the process described in  claim 10 .  
     
     
         24 . A permeable, foam coated, nonwoven  25 . A foam coated, nonwoven fibrous mat made by the process described in  claim 16 , fibrous mat made by the process described in  claim 15 .  
     
     
         25 . A foam coated, nonwoven fibrous mat made by the process described in  claim 16 ,  
     
     
         26 . A foam coated, nonwoven fibrous mat made by the process described in  claim 17 ,  
     
     
         27 . A laminate comprising a first material layer bonded to a second layer of a nonwoven fibrous mat, the mat having a coating on one surface and made by the process described in  claim 1 .  
     
     
         28 . A laminate comprising a first material layer bonded to a second layer of a nonwoven fibrous mat, the mat having a coating on one surface and made by the process described in  claim 2 .  
     
     
         29 . The laminate of  claim 27  wherein the first layer is gypsum board.  
     
     
         30 . The laminate of  claim 27  wherein the first layer is a light-weight insulating material.  
     
     
         31 . In a method of making a permeable fibrous mat on a wet process mat machine in which an aqueous slurry containing fibers is continuously deposited onto the top surface of a moving permeable forming belt, partially dewatered, followed by applying an excess of aqueous binder, removing excess aqueous binder to form a wet, bindered web and drying the wet, bindered web to produce a dry non-woven fibrous mat, the improvement comprising applying a foam onto the wet, bindered web before said web is dried, the foam having a high percentage of air having a density of below 83.3 gms/liter, the foam forming less than 10 milliliters of liquid in the bottom of an Imhoff cone after setting 10 minutes, and applying said foam at a rate to produce a dry mat having a coating on one face, heating the foam coated mat to at least partially collapse the foam to produce a dry mat having a permeability of at least about 0.37 CMM/sq. meter.  
     
     
         32 . The method of  claim 31  wherein at least the majority of the fibers are glass fibers and said foam is applied at a rate to produce a dry mat having a permeability of at least about 0.9 CMM/sq. meter.  
     
     
         33 . The method of  claim 32  wherein said foam is applied at a rate to produce a dry mat having a permeability of at least about 1.29 CMM/sq. meter.  
     
     
         34 . The method of  claim 31  wherein the foam has a density just prior to the applicator of less than 40 gms/liter.  
     
     
         35 . The method of  claim 32  wherein the foam has a density just prior to the applicator of less than 40 gms/liter.  
     
     
         36 . The method of  claim 33  wherein the foam has a density just prior to the applicator of less than 40 gms/liter.  
     
     
         37 . The method of  claim 31  wherein the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 millimeters.  
     
     
         38 . The method of  claim 35  wherein the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 millimeters.  
     
     
         39 . The method of  claim 32  wherein the amount of liquid formed in the bottom of the Imhoff is less than about 2 millimeters.  
     
     
         40 . The method of  claim 33  wherein the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 millimeters.  
     
     
         41 . The method of  claim 34  wherein the amount of liquid formed in the bottom of the Imhoff cone is less than about 2 millimeters.  
     
     
         42 . A permeable, coated, fibrous, nonwoven mat made by the process described in  claim 31 .  
     
     
         43 . A permeable, coated, fibrous, nonwoven mat made by the process described in  claim 32 .  
     
     
         44 . A permeable, coated, fibrous, nonwoven mat made by the process described in  claim 33 .  
     
     
         45 . A permeable, foam coated, fibrous, nonwoven mat made by the process described in  claim 34 .  
     
     
         46 . A permeable, foam coated, fibrous, nonwoven mat made by the process described in  claim 35 .  
     
     
         47 . A permeable, foam coated, fibrous, nonwoven mat made by the process described in  claim 36 .  
     
     
         48 . A permeable, foam coated, fibrous, nonwoven mat made by the process described in  claim 37 .  
     
     
         49 . A laminate comprising a first material layer bonded to a second layer of a nonwoven fibrous mat, the mat having a coating on one surface and made by the process described in  claim 31 .  
     
     
         50 . A laminate comprising a first material layer bonded to a second layer of a nonwoven fibrous mat, the mat having a coating on one surface and made by the process described in  claim 32 .  
     
     
         51 . The laminate of  claim 49  wherein the first layer is gypsum board.  
     
     
         52 . The laminate of  claim 49  wherein the first layer is a light-weight insulating material.  
     
     
         53 . The method of  claim 1  wherein the foam also contains insoluble particles to provide additional functionality to the coating.  
     
     
         54 . The method of  claim 2  wherein the foam also contains insoluble particles to provide additional functionality to the coating.  
     
     
         55 . The method of  claim 3  wherein the foam also contains insoluble particles to provide additional functionality to the coating.  
     
     
         56 . The method of  claim 31  wherein the foam also contains insoluble particles to provide additional functionality to the coating.  
     
     
         57 . The method of  claim 1  in wherein the foam is applied with a foam applicator as shown in FIG. 3.  
     
     
         58 . The method of  claim 7  in which the foam is applied with a foam applicator as shown in FIG. 3.  
     
     
         59 . The method of  claim 31  in which the foam is applied with a foam applicator as shown in FIG. 3.  
     
     
         60 . The method of  claim 33  in which the foam is applied with a foam applicator as shown in FIG. 3.  
     
     
         61 . The method of  claim 36  in which the foam is applied with a foam applicator as shown in FIG. 3.