RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 14/845,168, filed Sep. 3, 2015, which claims the benefit of U.S. Provisional Patent Application No. 62/045,489, filed Sep. 3, 2014, entitled “PARTITION DOOR HAVING SOUND ATTENUATING COATING” which are hereby incorporated by reference in their entireties, including, but not limited to, those portions that specifically appear hereinafter, this incorporation by reference being made with the following exception: In the event that any portion of the above referenced applications are inconsistent with this application, this application supercedes said above referenced applications. 
     
    
     BACKGROUND 
       [0002]    1. The Field of the Present Disclosure 
         [0003]    The present disclosure relates generally to partition doors and sliding doors used to divide areas of a room or space, or to seal off a particular area. The partition doors may also include sound attenuating characteristics. 
         [0004]    2. Description of Related Art 
         [0005]    A partition, accordion, or sliding door is generally used to divide areas of a room or space, or to seal off a particular area in case of needed security or possible danger. Partition doors are generally opaque, thus providing privacy between areas divided by the door. In addition to visual privacy, partition doors can provide a level of sound attenuation. 
         [0006]    Sound attenuation in partition doors is often facilitated by the use of fiberglass insulation attached to an interior of the door. However, fiberglass insulation can be difficult to secure or fasten to the door, resulting in displacement of the insulation during use, which can require additional maintenance and replacement of the fiberglass insulation. 
         [0007]    The features and advantages of the present disclosure will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by the practice of the present disclosure without undue experimentation. The features and advantages of the present disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The features and advantages of the disclosure will become apparent from a consideration of the subsequent detailed description presented in connection with the accompanying drawings in which: 
           [0009]      FIG. 1  is a perspective view of a partition door; 
           [0010]      FIG. 2 a    is a bottom view of an embodiment of the present disclosure, including a slat and sound attenuating coating; 
           [0011]      FIG. 2 b    is a bottom perspective view of the embodiment of  FIG. 2 a   , including a slat and sound attenuating coating; 
           [0012]      FIG. 2 c    is a bottom perspective view of the embodiment of  FIG. 2 a   , including multiple slats configured in a collapsed position; 
           [0013]      FIG. 2 d    is a bottom perspective view of the embodiment of  FIG. 2 a   , including multiple slats configured in a partially opened position; 
           [0014]      FIG. 3 a    is a perspective view of the embodiment of  FIG. 2 a   , including a plurality of adjoined slats having a sound attenuating coating; 
           [0015]      FIG. 3 b    is a perspective view of the embodiment of  FIG. 2 a   , including a plurality of adjoined slats having a sound attenuating coating in an opened position; 
           [0016]      FIG. 3 c    is a bottom view of the embodiment of  FIG. 2 a   , including a plurality of adjoined slats having a sound attenuating coating; 
           [0017]      FIG. 3 d    is a side view of the embodiment of  FIG. 2 a   , including a plurality of adjoined slats having a sound attenuating coating; 
           [0018]      FIG. 4 a    is a side view of the embodiment of  FIG. 2 a   , including a slat having a sound attenuating coating; 
           [0019]      FIG. 4 b    is a side view of a bottom portion the embodiment of  FIG. 2 a   , including a slat having a sound attenuating coating; 
           [0020]      FIG. 4 c    is a side view of the embodiment of  FIG. 2 a   , including a hinge coupled to a slat having a sound attenuating coating; 
           [0021]      FIG. 4 d    is a bottom view of the embodiment of  FIG. 2 a   , including a slat having a sound attenuating coating; 
           [0022]      FIG. 5  is a schematic view of a process for applying a sound attenuating coating to a partition door slat; 
           [0023]      FIG. 6  is a transmission loss chart for a sample door having fiberglass insulation; 
           [0024]      FIG. 7  is a transmission loss chart for a sample door having a single layer of sound attenuating coating; and 
           [0025]      FIG. 8  is a transmission loss chart for a sample door having a double layer of sound attenuating coating. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    For the purposes of promoting an understanding of the principles in accordance with the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Any alterations and further modifications of the inventive features illustrated herein, and any additional applications of the principles of the disclosure as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure claimed. 
         [0027]    It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. 
         [0028]    In describing and claiming the present disclosure, the following terminology will be used in accordance with the definitions set out below. 
         [0029]    As used herein, the terms “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps. 
         [0030]    Applicant has discovered a novel partition door having a sound attenuating coating, eliminating a need for additional or alternative sound attenuating material, and a method or process for applying the sound attenuating coating to an interior surface of a partition door. 
         [0031]      FIG. 1  illustrates an exemplary embodiment of a partition door  100 . The partition door  100  includes a plurality of adjoined slats  102 . Each slat  102  is suspended from a track  104  such that each of the slats  102  hangs vertically from the track  102  toward a floor  106 , partitioning a room or other desired space. Each of the slats  102  are hinged or coupled to an immediately adjacent slat  102  via a hinge  108 . The hinges  108  can be made of a malleable or flexible material that enables the slats  102  to bend with respect to adjacent slats  102 , in an accordion-type fashion, while also maintaining a connection between the slats  102 . 
         [0032]    A set of adjoined and adjacent slats  102  form a wall. The partition door  100  includes two walls (only one wall is illustrated in  FIG. 1 ) substantially abutting one another along a vertical axis of each wall. Thus, each wall includes an exterior surface and an interior surface. The interior surface substantially abutting the opposing wall. 
         [0033]    Each of the slats  102  can be made of metal, such as aluminum, or wood, polymer or other desired rigid or semi-rigid material. The slats  102  can be substantially planar or can have a waved shape as shown in  FIGS. 2 a -4 d   . The slats  102  can be approximately  4  inches in width, for example, and have a height that corresponds to the height of a room or desired space to ensure substantially complete partitioning of the desired room or space. The slat  102  widths may also be approximately 4.5 inches, or any other desired width. 
         [0034]      FIGS. 2 a - d , 3 a - d , and 4 a - d    show a series of adjoined slats  102  that include a sound attenuating coating  110 . The sound attenuating coating  110  can be applied and fixed to an inner surface of the slats  102 . As shown in  FIGS. 2 a -4 d , 3 a - d , and 4 a - d   , the coating  110  can be applied and fixed to the center (or any other desired portion of the slat  102 , or over the entire inner surface of the slat  102 ) of the slat  102 , along a vertical axis of the slat  102 , such that the coating will cover approximately 4 inches of the width of the slat  102  and extend substantially the entire vertical height (or length) of the slat  102 . Alternatively, the coating  110  can cover the entire inner surface of the slat  102  or a smaller desired surface area of the slat  102 . 
         [0035]    The coating  110  acts as a sound barrier and reduces the sound transfer between areas that are partitioned by the door  100 . The coating  110  can replace more traditional insulators, like fiberglass, which can be more difficult to install and attach to the slats  102 , and usually requires insulation fastening elements to attach the insulation to the slats  102 . 
         [0036]    Additionally, traditional insulators often need frequent maintenance due to a tendency for the traditional insulators, particularly fiberglass, to be displaced from the corresponding slats  102  or otherwise become damaged during use of the door. The displacement of the fiberglass insulation can cause the fiberglass to break apart and release airborne particulate into the surrounding air. Airborne fiberglass particles can become a significant health concern to nearby people or animals, for example, causing respiratory problems. Traditional insulators also tend to have lower sound attenuating capabilities at lower frequencies, however, the coating  110  out performs traditional insulators, specifically fiberglass insulation, in attenuating low frequency sound. 
         [0037]    In contrast, the coating  110  adheres directly to the surface of the slats  102  and therefore remains fixed to the slat  102  for substantially the life of the door  100 , thereby eliminating any airborne fiberglass particles that can be problematic with the use of traditional insulation. The coating  110  is also more efficiently fixed to the slats  102 , when compared to fixing traditional insulators to the slats  102 , through a spray application process described in more below and illustrated in  FIG. 5 . The spray application process saves time and installation cost because the spray application process can be performed as part of the manufacturing process of the slats  102 . Therefore, there is no need to add insulation on site or during the door  100  installation process. 
         [0038]    The coating  110  also increases the weight of the door  100 , when compared to traditional fiberglass insulation. The added weight aids in reducing swaying of the door  100  during use, thereby improving the sliding of the door  100  and reducing potential damage caused by frequent or excessive sway of door  100  during operation. The added weight and uniform distribution of the coating  110  also act to reinforce the slats  102 , providing additional strength and durability to withstand minor impacts during use and operation of the door  100 . 
         [0039]    It is estimated that use of the coating  110  may increase the lifetime and longevity of the door  100  by approximately 85% over the traditional use of fiberglass insulation with conventional attachment features. Additionally, the use of the coating  110  may even increase the lifetime and longevity of the door  100  by 20% over alternative fiberglass insulation configurations having improved mechanical attachment features. Furthermore, due to the added weight, strength, and stabilizing characteristics of the coating  110 , the door  100  may more effectively absorb and evenly distribute impact energy, which can significantly reduce damage to the door caused by impacts or other unintended manipulation of the door, which might otherwise cause damage. 
         [0040]    The uniform distribution and relatively small thickness of the coating  110 , when compared to fiberglass insulation, also enable the door  100  to more completely compress adjacent slats  102  when the door  100  is in an open position (like a closed accordion), increasing the space efficiency of the door  100 . 
         [0041]      FIG. 6  provides a transmission loss chart which includes the transmission loss of a sample door having fiberglass insulation. As shown in the chart, the fiberglass qualifies as a Sound Transmission Class (STC)  38  and an Outside Inside Transmission Class (OITC)  25 . ASTM publications E413-10 “Classification for Rating Sound Insulation” and E1332-10a “Standard Classification for Rating Outdoor-Indoor Sound Attenuation” are now incorporated herein in their entireties by this reference. 
         [0042]      FIG. 7  provides a transmission loss chart that includes the transmission loss of a sample door having a single layer of the coating  110 , having a total thickness of approximately 0.09 inches. As shown on the chart, the single layer of coating  110  qualifies as a STC  39  and an OITC  28 . 
         [0043]      FIG. 8  provides a transmission loss chart that includes the transmission loss of a sample door having two layers of the coating  110 , having a total thickness of approximately 0.18 inches. As shown on the chart, the double layer of the coating  110  qualifies as a STC  42  and an OITC  30 . 
         [0044]    Comparing the test results shown in the transmission loss charts in  FIGS. 6-8 , the coating  110  significantly improves the sound attenuating capabilities of the sample door. Some of the most significant sound attenuation improvements between the coating  110  and the fiberglass insulation occur at the lower frequency range (50-800 Hz), which can greatly improve the performance of the door  100 . For example, fiberglass has a transmission loss of 11 dB at 50 Hz, however, a single layer of coating offers a transmission loss of 13 dB at 50 Hz and a double layer of the coating  110  offers a transmission loss of 14 dB at 50 Hz. In another example, the fiberglass has a sound transmission loss of 20 dB at 160 Hz, however a single layer of the coating  110  offers a transmission loss of 23 dB at 160 Hz and a double layer of the coating  110  offers a transmission loss of 28 dB at 160 Hz. 
         [0045]    The coating  110  can be a polyurea material that is designed to be applied to and permanently fixed directly to the slats  102 . The coating has adhesive characteristics which enable it to adhere directly to the slat  102  without the need for additional adhesives or a mechanical fixation element. The coating  110  can be designed with an extended gel time for better leveling, forming a substantially planar interior surface, and high abrasion resistance for demanding industrial applications. The coating  110  can also provide less shrinkage and improved elongation, thus providing for efficient and reliable containment on the inner surface of the slats  102 . The coating  110  is also designed to provide a continuous, seamless membrane over the surface of the slats  102 . 
         [0046]    The coating  110  can include, for example, the following composition and ingredients: dialkylaminodiphenylmethane at 10-30% by weight, 2,4-diethyltoluenediamine at 7-13% by weight, triethanolamine at 5-10% by weight, poly(oxy(methyl-1,2-ethanediyl)), aplpha-(2-aminomethylethyl) omega-(2-aminomethylethoxy) at 5-10% by weight, and 2,6-diethyltoluenediamine at 1-5% by weight. Other polyurea and polymer materials having similar sound attenuating characteristics can also be used to compose the coating  110 . 
         [0047]    The coating  110  can also be characterized by its performance properties, namely, an ultimate elongation of approximately 370% and a tensile strength of approximately 2000 PSI, a tear strength of approximately 365 PLI, a hardness of approximately 45 Shore D and a dielectric strength of approximately 433 V/mil. The coating  110  can also be water resistant and provide protection against corrosion. 
         [0048]    As shown in  FIG. 5 , the coating  110  can be applied to a corresponding slat  102  as part of the manufacturing process, as opposed to on site as part of the door  100  installation process. The slat  102  is formed to the desired specification in a conventional process using a roll form mechanism  112 . Upon exiting the roll form mechanism  112 , the slat  102  can be forced along a conveyor ramp  114 . 
         [0049]    Before the coating  110  can be applied to the slat  102 , the slat  102  can pass through a cleaning station  116  where the surface of the slat  102  is cleaned of dirt, soluble salts, dust, oils, grease, chalking and contaminants. The cleaning station  116  can include a vacuum, blow-off, solvent cleaning, and/or water-wash containing salt solubilizing agents. 
         [0050]    After passing through the cleaning station  116 , the slat  102  then passes through a first spray application station  118  where a first layer of the coating  110  is sprayed onto the surface of the slat  102 . As described above, the coating  110  is applied along the entire length of the slat  102  and over a desired width, for example, 4 inches of a 4.5 inch slat  102 , although alternative widths and configurations can be used. The thickness of the coating  110  can usually be between 60-200 mils. 
         [0051]    To further improve the sound attenuation of the coating  110 , a second layer of the same sound attenuating coating can be applied over the top of the first layer of the coating  110 , with each layer having a thickness between 60-100 mils. Thus, after the slat  102  has passed through the first spray application station  118  the coating thickness may be increased by a second layer of the coating  110  which can be applied in the same or similar manner. 
         [0052]    After passing through the first spray application station  118 , the slat  102  will continue along the conveyor ramp  114  through a dryer  120 . The dryer  120  can be an air dryer, possibly blowing heated air, to speed the drying and curing of the first layer of the coating  110 . 
         [0053]    After passing through the dryer  120 , the slat  102  can then pass through a second spray application station  122  where a second layer of the coating  110  can be sprayed onto the surface of the slat  102 , if a second layer is desired. There may be circumstances where one, single layer of the coating  110  is sufficient and/or desirable. As with the first layer, the second layer of the coating  110  is applied along the entire length of the slat  102  and over a desired width, for example, 4 inches of a 4.5 inch slat  102 . The total thickness of the coating  110  after passing through the second spray application station  122  can usually be between about 60 and about 200 mils. 
         [0054]    After passing through the second spray application station  122  the slat  102  can be sheared, or otherwise cut, to the desired length and set aside to fully cure. Drying and curing times of the coating  110  include: 10-15 seconds to gel, 20-30 seconds until tack free, approximately 8 hours until a hard dry, and can be immersed in water, without detrimental effect, in approximately 24 hours. 
         [0055]    The process of coating the slats  102  can be continuously performed until the desired number of slats has been reached. After curing of the coating  110  is complete, the slats  102  can be transported to a desired site to be assembled as part of the partition door  100 . 
         [0056]    It is to be understood that the above-described arrangements are only illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present disclosure are intended to cover such modifications and arrangements. Thus, while the present disclosure has been shown in the drawings and described above with particularity and detail, it will be apparent to those of ordinary skill in the art that numerous modifications, including, but not limited to, variations in size, materials, shape, form, function and manner of operation, assembly and use may be made without departing from the principles and concepts set forth herein.
A partition door including, a plurality of door slats, wherein each of the door slats are suspended from a track and extend vertically toward a floor. Each of the door slats are moveable in a generally horizontal direction. The partition door also includes a plurality of hinges, each hinge coupling adjacent door slats. The partition door further including a sound attenuating coating fixed to a first surface of at least one of the plurality of door slats.