Abstract:
The invention relates to a composition for use in the production of an article of manufacture, and in particular, to the manufacture of wall and corner guards. The composition includes a biopolymer in combination with PETG as well as a modifier. The biopolymer and modifier are preferably produced from an annually renewable source such as corn or sugar as opposed to traditionally used petroleum based plastics. In this manner, the composition of the invention is relatively environmentally friendly as compared to known compositions while maintaining many of the desirable qualities thereof. In addition, the production of the articles of manufacture results in the consumption of fewer fossil fuels and less production of pollutants.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of provisional application No. 61/314,023 filed on Mar. 15, 2010 and entitled “Door and Wall Protection Structures and Material for Producing the Same.” 
    
    
     FIELD OF THE INVENTION 
     This invention relates to door and wall protection structures, and, more particularly, to a material for constructing door and wall protection structures from. 
     BACKGROUND OF THE INVENTION 
     It is often desirable to provide wall and door mounted structures for protecting the door and wall from general wear and tear often experienced by high traffic areas. For instance, such structures are commonly used in schools, hospitals, nursing homes, and other settings where there is a large amount of pedestrian traffic such that the walls and doors experience a relatively high amount of wear and tear as compared to less trafficked areas. Further, large equipment is typically moved in and out of hallways and doors of these locations, which may cause the doors and walls to experience additional wear and tear. For example, in hospitals, patient beds, gurneys, wheel chairs, mobile imaging equipment, and the like are often moved from one place to another and in doing so often unintentionally impact the walls and doors in the areas which they travel past. Accordingly, these locations often employ protection structures such as wall and door guards to protect against this wear and tear. 
     Wall and door guards used in such applications are typically constructed from vinyl or other plastic materials. The production of such materials is often associated with the production of a relatively large amount of pollutants. Moreover, such processes typically utilize a number of chemicals and other hazardous materials that may be harmful to the environment. For instance, known materials typically include halogens, sulfur, nitrogen, lead, mercury, cadmium, hexavalent chromium, or other known materials that may have an adverse impact on the environment. 
     Thus, a material for constructing wall and door guards that is capable of protecting walls and doors from wear and tear but which is more environmentally friendly is desired. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a composition and method for producing the composition is provided to form a composition having an improved environmental impact as compared to materials typically used to construct wall and door guards. 
     The composition of the present invention may include a biopolymeric component, a polyethylene terephthalate (PET) copolymer, and a modifier component. The PET copolymer may include polyethylene terephthalate glycol (PETG). The biopolymer may be PLA or some similar material. The modifier of the composition may comprise approximately 20% of the composition. The PETG component may comprise approximately 60% of the composition. The PLA component may be provided in approximately 20% of the composition. Of course, the composition may be modified to include more or less of any of the foregoing components or to add additional components. 
     The composition of the present invention may be utilized for the molding or otherwise constructing of an article of manufacturing such as, for example, a wall or corner guard. The wall or corner guard may include a base and a cover. The base may be constructed out of a relatively sturdy material such as a metal like aluminum or the like. The cover may be slidingly coupled to the base so as to selectively cover the base. The cover is constructed from the material of the present invention. In this manner, the cover is constructed so as to provide protection to the walls and surrounding areas of a given location during use thereof. At the same time, the composition of the material of the present invention is such that it is generally more environmentally friendly. Finally, a method of forming the article may include the steps of providing a biopolymer component, a PET copolymer component and a modifier component in combination with one another to form the material of the present invention. The method may further include the steps of providing an additive component for enhancing a characteristic of the material. For instance, the additive component may be one of a colorant, a flame retardant, a UV stabilizer, matting agent, and a slip agent. 
     Numerous other aspects, features and advantages of the invention will be made apparent from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is an isometric view of a corner guard constructed in accordance with the present invention mounted to a corner of a wall; 
         FIG. 2  is an isometric view of another construction of a corner guard constructed in accordance with the present invention; 
         FIG. 3  is an isometric view of a wall and corner guard assembly constructed in accordance with the present invention; 
         FIG. 4  is an end elevation view of a wall guard constructed in accordance with the present invention; 
         FIG. 5  is a side elevation view of the wall guard of  FIG. 4 ; 
         FIG. 6  is a top plan view of the wall guard of  FIG. 4 ; 
         FIG. 7  is a bottom plan view of the wall guard of  FIG. 4 ; 
         FIG. 8  is a cross-sectional view of the wall guard of  FIG. 4 ; 
         FIG. 9  is a partial isometric view of the wall guard of  FIG. 4  illustrating a cover removed from a portion of a base thereof; 
         FIG. 10  is an isometric view of a corner guard constructed in accordance with the present invention; 
         FIG. 11  is an end elevation view of the corner guard of  FIG. 9 ; 
         FIG. 12  is a cross-sectional view of the corner guard of  FIG. 9  taken along line  9 - 9 ; and 
         FIG. 13  is a bottom plan view of the corner guard of  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is a material for extruding wall and door guards that comprises the same durability and other characteristics of traditional materials such as vinyl and other such known materials, but which is produced, at least in part, from a renewable source and, and wherein the production of the composition utilizes less fossil fuel and releases fewer amounts of greenhouse gasses than comparable petroleum-based plastics. 
     Referring to the drawings, and initially to  FIG. 1 , an exemplary corner guard assembly  20  constructed in accordance with the present invention is illustrated. Corner guard assembly  20  includes a protective element  22  coupled around a corner  24  joining two walls  26 ,  28  together. As shown, corner guard assembly  20  extends upwardly from the floor surrounding corner  24  and terminates in an upper cap  30  that is secured over an upper edge of the protective element  22 . Cap  30  may be generally sized and shaped to cover the upper edge of the corner guard element such that the rear side of the corner guard assembly  20  is generally concealed. Corner guard assembly  20  may have a height sufficient to accommodate the passage of various transport assemblies such as wheelchairs, gurneys, hospital beds, portable monitoring equipment carts, and other such assemblies configured for transporting people or equipment. In this manner, the corner guard assembly  20  may protect the walls  26 ,  28  from accidental damage caused by such equipment striking the walls  26 ,  28 . Of course, corner guard assembly  20  may extend along an entire height of the walls  26 ,  28  or just a portion. Further, corner guard  20 , as illustrated, extends a predetermined distance onto each of the walls  26 ,  28  around corner  24 . The distance about which corner guard assembly  20  extends onto each of the walls  26 ,  28  may be any distance desired and need not be disposed symmetrically across both of the walls  26 ,  28 . 
     Turning now to  FIG. 2  another construction of a corner guard assembly  20  according to the present invention is illustrated. In the present construction, protective element  22  is coupled to wall  26  and extends along wall  26  and over corner  24  but does not extend onto wall  28 . The corner guard assembly  20  of this construction includes a cap  30  and operates similarly to that of the previous construction. 
     Referring to  FIG. 3 , a wall and corner guard assembly  32  according to the invention is illustrated. The wall and corner guard assembly  32  includes a number of generally elongate wall protective elements  34  that extend along a width of the walls  36 ,  38 . The wall protective elements  34  are interconnected with a number of corner protective elements  40  that are configured to wrap around a corner  42  between walls  36 ,  38 . Wall and corner guard assembly  32  of the present construction may incorporate a handrail assembly  44  as is generally understood. Handrail assembly  44  may be constructed like that disclosed in U.S. patent application Ser. No. 12/418,303 filed on Apr. 3, 2009 and entitled “Handrail Assembly.” 
     Referring now to  FIGS. 4-8 , an exemplary illustration of a wall guard  46  according to the invention is illustrated. Wall guard  46  includes a base  48  slidably coupled to a cover  50 . Base  48  is generally flat in construction and may be constructed from a metal or similarly durable material configured to support the wall guard  46 . Base  48  may include a pair of laterally positioned flanges  52  disposed on opposing sides thereof. Flanges  52  may extend generally upwardly from a lower edge of base  48  and may be generally configured for engaging a portion of cover  50  to allow base  48  to slide with respect thereto. Flanges  52  may extend along an entire length of base  48  or a portion thereof. Base  48  may include a pair of centrally disposed support elements  54  that extend along a length thereof. Elements  54  may be integrally formed with an upper portion of base  48  and may have a generally L-shaped cross-section or any other similarly suitable shape. Elements  54  may be configured to receive a reinforcing element  56 . Reinforcing element  56  may have a generally C-shaped construction and include a pair of laterally disposed flanges  58  configured to engage elements  54 . Element  56  may be generally configured to provide the cover  48  with additional structural support as will be discussed further. Element  56  may be constructed out of metal, plastic, or any other suitable material as desired. 
     Base  48  is secured to and carries an end member  60  configured to be positioned flush with respect to cover  50  as will be discussed. End member  60  serves as a cover to keep the base  48  hidden from view from an exterior of wall guard  46 . End member  60  may include a generally rounded portion that is positioned flush with cover  50 . The rounded portion of end member  60  terminates in a ledge that is undercut with respect to the rounded portion and configured to be received under cover  50 . End member  60  further includes a mounting arrangement  62  that extends downwardly from the ledge thereof. Mounting arrangement  62  is secured to an upper face of base  48 . Mounting arrangement  62  includes a number of grooves  64  configured to engage a portion of base  48  to thereby couple end member  60  to the base  48 . In particular, mounting arrangement  62  includes a pair of laterally disposed grooves  64  that are configured to receive ends of support elements  54 . Support elements  54  are secured within grooves  64  by way of a friction fit, adhesive, or any other such means known in the art. A centrally disposed groove  64  is configured to receive a fastener  66  therethrough. In particular, groove  64  may receive, for instance, the shank of a screw or similar element therethrough and a nut or the like may be received over the end of the screw. The fastener  66  may be received through the base  48  and secured through the groove  64  to thereby secure the end member  60  to the base  48 . 
     Cover  50  of the wall guard  46  is constructed from a material according to the present invention as will be discussed herein. Cover  50  is generally C-shaped and includes a relatively flat surface  68  and a pair of rounded sides  70 . Rounded sides  70  terminate in inwardly flanged ends  72  that extend along the length of cover  50  and are configured to engage the flanges  52  of the base  48 . In particular, ends  72  are configured to slidably receive the respective flanges  52 . In this manner the base  48  is slidable with respect to the cover  50  for assembling the wall guard  46 . A number of alternative arrangements are considered to be within the scope of the present construction of wall guard  46 , and the foregoing description is meant to be merely exemplary. It is understood that any number of traditional wall guard constructions are within the scope of the present invention, and the present invention need not be limited to the foregoing described construction. 
     Referring now to  FIGS. 9-12 , a corner guard  74  constructed from a material according to the present invention as will be discussed further herein is illustrated. The corner guard  74  is similarly constructed as compared to wall guard  46 , and therefore, the foregoing description of the wall guard  46  is generally applicable to the corner guard  74 . Corner guard  74  includes a base  48  and a cover  50 . The base  48  and cover  50  are slidably engageable with one another. Base  48  includes an end member  60  secured by way of a fastener or other such arrangement. Base  48  is generally bent about a central axis extending along a length thereof. In this way, base  48  is configured to be received about a corner of a wall as is generally understood. Base  48  includes a pair of flanges  52  that are selectively engageable with cover  50  to enable base  48  to slide with respect the cover  50  for assembly of corner guard  74 . Base  48  may include a mounting arrangement. 
     Cover  50  of corner guard  74  is sized and shaped to accommodate base  48  and includes a pair of rounded sides  70  that terminate in ends  72  extending along the length of the sides thereof for engaging the flanges  52  of base  48 . Flanges  48  are thus slidably engageable with the ends  72  for sliding movement of the base  48  with respect to the cover  50 . Cover  50  may be generally V-shaped to thereby be received around a corner of a wall much like base  48 . In this manner, corner guard  74  may be coupled between a pair of adjacent walls around a corner thereof as shown, for example, in  FIG. 1 . 
     Base  48  may include an end  60  coupled thereto by a pair of fasteners, other mechanical or non-mechanical means. For instance, base  48  may include a pair of apertures  76  for receiving a pair of fasteners (not shown) to thereby couple the end  60  to the base  48  in much the same manner as illustrated in the previously discussed construction of the present invention. 
     The material of the invention includes Polyethylene Terephthalate Glycol (PETG) and a predetermined amount of recycled content in combination with a biopolymer, and in particular, polylactic acid (PLA) and a modifier. 
     The composition of the invention is particularly useful in that it maintains many of the characteristics of commonly used plastics such as vinyl while also having improved environmental characteristics in that the composition does not include halogens, lead, mercury, cadmium, hexavalent chromium, or BPA. The resulting material is NFPA class 1 fire rated such that it may be used in any number of applications. 
     The material of the invention includes a biopolymer that is biodegradable thermoplastic, aliphatic polyester derived from a renewable resource such as corn starch or sugar cane, though other annually renewable resources are within the scope of the present invention. The biopolymer of the invention may be polylactic acid (polylactide or PLA). PLA is generally compostable thereby providing a relatively environmentally friendly product. PLA is made primarily of polylactic acid, a repeating chain of lactic acid, which undergoes a two-step degradation process. The conversion of Lactide to Polylactide under the presence of a catalyst and heat is illustrated below. 
     
       
                 
         
             
             
         
      
     
     As is known in the art, PLA can be processed like most thermoplastics into fiber using conventional melt spinning processes and the like or a film. The melting temperature of PLA may be changed with the addition of another compound. The PLA used in the present invention may be that produced by NatureWorks®, though other producers may be utilized. Preferably, the PLA utilized in the preferred embodiment is preferably PLA Polymer 2002D sold by NatureWorks®. 
     The material of the invention additionally includes a PET copolymer such as PETG. PETG is a clear amorphous thermoplastic that can be injection molded or sheet extruded. PETG may also be colored during processing. As is generally understood, copolymers such as PETG are useful in molding applications such as thermoforming to make products such as tray and blister packaging from PETG film and PETG sheet. The PETG may be that produced by Eastman Chemical Company sold under the name Eastman Spectar™ Copolyester 14471 although other producers may be used for supplying the PETG of the invention. 
     The material of the invention further includes a modifier such as a flexible plastic for film extrusion and extrusion coating. In particular, the modifier of the invention should be biodegradable and have processing properties substantially similar to LDPE and LLDPE. Further, the material should require no pre-drying prior to extrusion thereof. The modifier may be ECOFLEX® F BX 7011 produced by BASF, REPRO, or a similar such composition. 
     One embodiment of the invention comprises approximately 60% PETG, 20% PLA, and 20% modifier such as ECOFLEX®. It is understood that these percentages are merely approximations and a range of varying concentrations of each of the components of the invention are contemplated and within the scope of the present invention. The resulting material of the invention should be relatively durable as compared to acrylic and similar such materials as well as comprise an excellent chemical resistance. The material further comprises easy, repeatable thermoforming capabilities, is relatively inflammable, and is relatively flexible. 
     To prepare the material of the present invention, the PETG, PLA, and modifier are mixed, blended or compounded together and extruded into a sheet or profile shape. The resultant material has a melting point of approximately 221 degrees Celsius (430 degrees Fahrenheit). The individual components are provided in a pellet form. The individual components are then dry blended at various rations right into the extruder, or alternatively, the individual components can be provided in pellet form and compounded together to form a single homogenous pellet comprising the three individual components of the invention. One advantage of compounding the individual components together rather than dry blending them into the extruder is that the resultant mixture is more thoroughly mixed to thereby allow for more consistent, reproducible processing for varying extrusion shapes. As is readily understood, additional components may be provided in the material of the invention such as, for example, color pellets to provide a resultant material having a different coloring. Likewise, flame retardants, UV-stabilizers, matting agent, slip agents, and the like may be included in the material of the invention. 
     One notable characteristic of the invention is that the PETG has a much higher melting temperature than the PLA or PLA modifier. Thus, as the materials are melted together, the tensile elongation experienced by the material is increased so as to provide an improved impact resistance as compared to prior art materials. In this manner, the addition of PETG to the PLA and modifier eliminates the rough edges often associated with a combination of PLA and a modifier. That is, when PLA and a modifier are combined, the resulting extrusion material has a lower melting point as compared to that of the invention with the addition of PETG. One problem associated with a lower melting point in an extruding material like that contemplated herein is that the edges of the material are susceptible to melting when an extrusion saw is applied to the material. As the material hardens the melting of the edges leaves behind rough areas around the edges. As is readily understood, providing an extruded material with rough edges is undesirable and thus the extruded material is either unusable or requires a great deal of finishing to remove the rough edges. This results in longer processing time and more wasted materials and thus greater expense. 
     Various alternatives are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.