Patent Document

RELATED APPLICATIONS 
     This application, U.S. patent application Ser. No. 13/114,954 filed May 24, 2011, is a continuation of U.S. patent application Ser. No. 11/982,134 filed Oct. 31, 2007, now U.S. Pat. No. 7,947,753 which issued May 24, 2011. 
     U.S. patent application Ser. No. 11/982,134 is a continuation of U.S. patent application Ser. No. 11/027,219 filed Dec. 29, 2004, now U.S. Pat. No. 7,374,068 which issued May 20, 2008. 
     U.S. patent application Ser. No. 11/027,219 claims benefit of U.S. Provisional Patent Application Ser. No. 60/617,236 filed Oct. 8, 2004. 
     All related applications cited in this Related Applications section, including the subject matter thereof, are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to particulate materials for use in acoustic texture material and, more particularly, to particulate materials that may be used in acoustic texture material formulated to be dispensed from aerosol dispensers. 
     BACKGROUND 
     Interior walls are formed by sheets of drywall material that are secured to the framing of a building. The seams between adjacent sheets of drywall material are taped, mudded, and sanded to obtain a substantially flat, smooth drywall surface. The drywall surface is coated with primer and paint to obtain a finished surface. 
     In some situations, a separate texture layer is applied to the drywall surface prior to painting. The texture layer is formed by spraying texture material onto the drywall surface. Texture material is a coating material that, when sprayed, does not form a smooth, thin coating. Instead, texture material is applied in discrete drops or globs that dry to form a bumpy, irregular textured surface. 
     Texture materials can be applied using any one of a number of application systems. During new construction, texture materials are commonly applied in a stream of compressed air using commercial hopper gun systems. For touch up or repair, texture material is commonly applied using hand operated pneumatic pumps or aerosol dispensing systems. Varying the parameters of the application system varies the size and spacing of the bumps to vary the look of the textured surface. 
     One specific form of texture material is commonly referred to as “acoustic” or “popcorn” texture material. In addition to a coating material, acoustic texture material further comprises an aggregate material. When the acoustic texture material is applied using commercial hopper guns, the aggregate material is conventionally formed by polystyrene chips. However, as will be described in detail below, chips made of polystyrene foam are dissolved by hydrocarbon aerosol propellant materials. 
     Accordingly, aerosol dispensing systems for dispensing small amounts of acoustic texture material for repair or touch-up purposes use one of two approaches. The first approach is to mix a liquid hydrocarbon aerosol propellant material with chips made from materials other than polystyrene. However, when chips made of materials other than polystyrene foam are used, the appearance and function of the texture surface may be different from that of the surrounding surface. 
     The second approach is to combine polystyrene chips with a propellant material formed by a pressurized inert gas such as nitrogen or air. This second approach allows the use of a conventional acoustic texture material including polystyrene chips. However, the use of a pressurized inert gas causes the acoustic texture material to be dispensed very quickly. The use of pressurized inert gas as a propellant can make it difficult for a non-professional to control the application of the acoustic texture material. 
     The need thus exists for improved systems and methods for dispensing small quantities of acoustic texture material for the purpose of touch-up or repair. 
     SUMMARY 
     The present invention may be embodied as a composition for forming a textured coating on drywall material, where the textured coating substantially matches a pre-existing acoustic texture material on the drywall material, comprising acoustic texture material and propellant material. The acoustic texture material comprises a base portion the base portion is capable of existing in a flowable state and a hardened state, and a particulate portion the particulate portion comprises discrete, visible particles of solidified urethane foam having irregular shapes. The propellant material comprises a hydrocarbon propellant. The particles of urethane foam are distributed throughout the acoustic texture material when the base portion is in the flowable state. The irregular shapes of the particulate portion are substantially the same when the base portion is in the flowable state and in the hardened state. The base portion is capable of securing the discrete, visible, particles of solidified urethane foam to the drywall material when the base portion is in the hardened state. 
     The present invention may also be embodied as a method of forming a textured coating on drywall material such that the textured coating substantially matches a pre-existing acoustic texture material on the drywall material comprising the following steps. Acoustic texture material comprising a base portion capable of existing in a flowable state and a hardened state and a particulate portion comprising discrete, visible particles of solidified urethane foam having irregular shapes is provided. The acoustic texture material is arranged within an aerosol assembly such that the particles of urethane foam are distributed throughout the base portion when the base portion is in the flowable state. Propellant material comprising a hydrocarbon propellant is arranged within the aerosol assembly. The aerosol assembly is operated such that the propellant material forces the acoustic texture material out of the aerosol assembly and onto the drywall material and the base portion changes to the hardened state such that the discrete, visible, particles of solidified urethane are secured to the drywall material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a section view of a first embodiment of an aerosol dispensing system containing acoustic texture material incorporating particulate material of the present invention; 
         FIG. 2  is a section view of a second embodiment of an aerosol dispensing system containing acoustic texture material incorporating particulate material of the present invention; 
         FIG. 3  is an elevation view depicting the use of one or both of the first and second aerosol dispensing systems of  FIGS. 1 and 2  being used to deposit acoustic texture material to a surface; 
         FIG. 4  is a section view of the acoustic texture material after it has been deposited on the surface; and 
         FIGS. 5 and 6  are bottom plan views of the surface before and after the acoustic texture material has been deposited thereon. 
     
    
    
     DETAILED DESCRIPTION 
     Referring initially to  FIG. 1  of the drawing, depicted at  20   a  therein is a first embodiment of an aerosol system for depositing on a surface  22  ( FIGS. 3-6 ) acoustic texture material  24  incorporating particulate material  26  of the present invention.  FIG. 5  illustrates a target portion  28  of the surface  22  on which acoustic texture material  24  is to be deposited. 
     The example aerosol system  20   a  comprises a container assembly  30 , a valve assembly  32 , a collection assembly  34 , and an outlet assembly  36 . The container  30  defines a product chamber  40  in which the acoustic texture material  24  comprising the particulate material  26  is contained. A first portion  42  of the chamber  40  is occupied by the acoustic texture material  24 , while a second portion  44  of the chamber  40  is occupied by a pressurized propellant material  46 . The example container assembly  30  comprises a can member  50  and a cup member  52 . 
     The valve assembly  32  is mounted in a cup opening  34  define by the cup member  52  and operates in a closed configuration (shown) and an open configuration. In the open configuration, the valve assembly  32  defines a dispensing passageway that allows fluid communication between the interior and the exterior of the container assembly  30 . 
     The outlet assembly  36  comprises an actuator member  60  that causes acoustic texture material  24  to be dispensed by the system  20  in a fan shaped spray as will be described in further detail below. The actuator member  60  is mounted on the valve assembly  32  such that displacing the outlet member  60  towards the valve assembly  32  places the valve assembly in the open configuration. 
     The example valve assembly  32  comprises a valve seat  70 , a valve stem  72 , a valve housing  74 , a dip tube  76 , and a valve spring  78 . The valve seat  70  defines a seat opening  70   a  and is supported by the cup member  52 . The valve stem  72  defines a valve stem opening  72   a  and a valve surface  72   b . The valve stem  72  is supported by the valve seat  70  such that the valve stem moves within the valve stem opening  72   a  between first and second positions, with the first position being shown in  FIG. 1 . 
     The valve housing  74  is supported by the valve seat  70  within the product chamber  40 . The valve housing  74  further supports the dip tube  76  such that the acoustic texture material  24  within can flow into the valve housing  74  when the can is upright. The valve spring  78  is supported by the valve housing  74  such that the spring  78  biases the valve stem  72  into the first position. The valve stem  72  supports the outlet assembly  36  such that depressing the actuator member  60  towards the cup member  52  forces the valve stem  72  into the second position (not shown) against the force of the valve spring  78 . 
     The valve assembly  32  thus operates in the closed configuration and the open configuration as follows. When no force is applied to the actuator member  60 , the valve spring  78  forces the valve surface  72   b  against the valve seat  70  to prevent fluid from flowing through the valve stem opening  72   a . When a force is applied to the actuator member  60 , the valve surface  72   b  is forced away from the valve seat  70  such that fluid can flow from the interior of the valve housing  74  through the valve stem opening  72   a  and thus out of the product chamber  40 . 
     Referring now to  FIG. 2  of the drawing, depicted at  20   b  therein is a first embodiment of an aerosol system that may also be used to deposit the acoustic texture material  24  incorporating particulate material  26  of the present invention on the target portion  28  of the surface  22 . 
     The example aerosol system  20   b  comprises a container assembly  130 , a valve assembly  132 , a collection assembly  134 , and an outlet assembly  136 . The container  130  defines a product chamber  140  in which the acoustic texture material  24  comprising the particulate material  26  is contained. A first portion  142  of the chamber  140  is occupied by the acoustic texture material  24 , while a second portion  144  of the chamber  140  is occupied by a pressurized propellant material  146 . The example container assembly  130  comprises a can member  150  and a cup member  152 . 
     The valve assembly  132  is mounted in a cup opening  134  define by the cup member  152  and operates in a closed configuration (shown) and an open configuration. In the open configuration, the valve assembly  132  defines a dispensing passageway that allows fluid communication between the interior and the exterior of the container assembly  130 . 
     The outlet assembly  136  comprises an actuator member  160  that causes acoustic texture material  24  to be dispensed by the system  20  in a fan shaped spray as will be described in further detail below. The actuator member  160  is mounted on the valve assembly  132  such that displacing the outlet member  160  towards the valve assembly  132  places the valve assembly in the open configuration. 
     The example valve assembly  132  comprises a valve seat  170 , a valve stem  172 , a valve housing  174 , a dip tube  176 , and a valve spring  178 . The valve seat  170  defines a seat opening  170   a  and is supported by the cup member  152 . The valve stem  172  defines a valve stem opening  172   a  and a valve surface  172   b . The valve stem  172  is supported by the valve seat  170  such that the valve stem moves within the valve stem opening  172   a  between first and second positions, with the first position being shown in  FIG. 1 . 
     The valve housing  174  is supported by the valve seat  170  within the product chamber  140 . The valve housing  174  further supports the dip tube  176  such that the acoustic texture material  124  within can flow into the valve housing  174  when the can is upright. The valve spring  178  is supported by the valve housing  174  such that the spring  178  biases the valve stem  172  into the first position. The valve stem  172  supports the outlet assembly  136  such that depressing the actuator member  160  towards the cup member  152  forces the valve stem  172  into the second position (not shown) against the force of the valve spring  178 . 
     The valve assembly  132  thus operates in the closed configuration and the open configuration as follows. When no force is applied to the actuator member  160 , the valve spring  178  forces the valve surface  172   b  against the valve seat  170  to prevent fluid from flowing through the valve stem opening  172   a . When a force is applied to the actuator member  160 , the valve surface  172   b  is forced away from the valve seat  170  such that fluid can flow from the interior of the valve housing  174  through the valve stem opening  172   a  and thus out of the product chamber  140 . 
     Turning now to  FIGS. 3-6 , the use of the aerosol dispensing systems  20   a  and  20   b  will now be described in further detail. These dispensing systems  20   a  and  20   b  are used in the same manner and are both identified by reference character  20  in  FIGS. 3-6 . 
     As shown in  FIG. 3 , the dispensing system  20  deposits a fan-shaped spray of acoustic texture material  24  on the target portion  28  of the wall  22 . As shown in  FIGS. 4 and 6 , the acoustic texture material  24  covers the target portion  28  to match the pre-existing acoustic texture material on the surface  22  surrounding the target portion  28 . 
     Referring for a moment back to  FIGS. 1 and 2 , it can be seen that, in addition to the particulate material  26 , the acoustic texture material comprises a base portion  220  in the form of a flowable liquid. The base portion  220  of the particulate material conventionally comprises a carrier, a filler, and a binder. 
     In some aerosol systems, the propellant material  46 , 146  is simply an inert pressurized gas such as air or nitrogen. In other aerosol systems, the propellant material  46 , 146  is a material, referred to herein as bi-phase propellant material, that exists in both gaseous and liquid phases within the container assembly  30 , 130 . The liquid phase of the propellant material  46 , 146  forms a part of the base portion  220 , while the gaseous phase propellant material  46 , 146  occupies the pressurized portion  44  of the container assembly  30 , 130 . 
     As the acoustic texture material  24  is dispensed, the pressure within the pressurized portion  44 , 144  of the container assemblies  30 , 130  drops. Under these conditions, a portion of the bi-phase propellant material  46 , 146  in the liquid phase gasifies to re-pressurize the pressurized portion  44 , 144  of the container assembly  30 , 130 . The pressure within the pressurized portion  44 , 144  is thus under most conditions sufficient to force the acoustic texture to material  24  out of the container assembly  30 , 130  along the dispensing passageway when the valve assembly  32 , 132  is in the open configuration. The propellant material  46 , 146  may thus be a pressurized inert gas such as air or nitrogen. 
     However, the present invention is of particular significance when the propellant material is a bi-phase propellant material such as di-methyl ethylene (DME) or any one of a number of hydrocarbon propellants such as those available in the industry as A-40 and A-70. The advantage of using bi-phase propellant materials is that the pressure within the pressurized portion  44 , 144  of the container assembly  30 , 130  is kept at a relatively constant, relatively low level as the level of acoustic texture material  24  drops. This constant, low level pressure allows the texture material  24  to be dispensed in many small bursts instead of in a few large bursts, as is the case when pressurized inert gases are used as the propellant material  46 , 146 . 
     Many particulate materials  26  suitable for use in acoustic texture materials are incompatible with bi-phase propellant materials. For example, as described above polystyrene chips are commonly used in acoustic texture materials dispensed using commercial hopper guns. However, polystyrene chips dissolve in the bi-phase propellant materials of which the Applicant is aware. 
     The Applicant has discovered that urethane foam materials and melamine foam materials may be used as the particulate material  26  with bi-phase propellant materials such as DME and hydrocarbon propellants such as A-40 and A-70. Melamine foam materials in particular are easily chopped up using conventional material processors (e.g., a food blender) into irregular shapes that match the appearance and function of polystyrene chips. Melamine foam materials are already commonly used in building applications and have desirable fire retardant, thermal, and acoustic properties. 
     To manufacture the acoustic texture material  24 , the base portion  220  may be the same as a conventional base used in commercially available acoustic texture materials. Instead of polystyrene chips, however, urethane and/or melamine foam is chopped up into particles of an appropriate size and use as the particulate. In addition, a bi-phase propellant material is used to form part of the carrier portion of the base portion  220 . 
     The Applicant has thus determined that a conventional base portion using melamine foam chips and DME as a propellant is commercially practical and obtains acceptable aesthetic and functional results. Appropriate adjustments in the liquids used as the carrier in a conventional acoustic texture material formulation may be required to obtain a desired consistency of the acoustic texture material  24  as it is deposited on the surface  22 .

Technology Category: 7