FIELD AND BACKGROUND OF THE INVENTION The present invention relates to improved roughened metal surfaces and methods of production thereof and, more particularly, to a coating applied to a metal surface. The coating includes both a liquid bonding media and particles adhered thereto. Some embodiments of the invention relate to use of untreated glass particles to create a reflective surface. These embodiments may be used, for example, to visualize road features by reflectorizing surfaces of metal rails or posts ordinarily installed on roadways. Other embodiments of the invention relate to use of particles which serve to roughen a surface in order to simplify removal of papers affixed thereto. These embodiments may be used, for example, to protect metal doors, junction boxes, signs or walls from posting of unwanted notices or advertisements.

Use of glass particles to impart reflectivity to a surface has previously been described in conjunction with marking of pavement surfaces.

For example, US patents 4,713, 295 and 5,128, 203 issued to Laroche mention the use of glass beads in mixtures for creating a reflective marking on a road surface. Specifically, LaRoche teaches application of chemical coatings to glass beads in order to control the degree in which they sink into a paint layer. Specifically, Laroche teaches that 40-60% submersion of the glass beads in paint is optimal. Thus, the teachings of Roche would lead one of ordinary skill in the art to conclude that use of untreated glass beads is undesirable, inefficient, or counterproductive because the untreated beads would not sink into the paint to provide a sufficient degree of bonding.

US patent 6,350, 823 issued to Goeb et al. is another example of glass beads being incorporated into pavement markings for reflective purposes. Like LaRoche, Goeb teaches use of chemical treatments to"... aid in achieving substantially uniform hemispherical bead sinkage." US patent application 20020090505 filed by Stoffers et al. is an example of a coating for reflective road markings which teaches that inclusion of glass with a particle size distribution in the range of 1. 18 to 2.36 mm into the coating layer helps to retain the reflecting properties of the system, in the dry state only, over time.

These four references all share a common assumption that the logical place to deploy paint with a layer of glass beads on its surface is on the pavement of a roadway. As such, all teachings contained therein are motivated by a common desire to mitigate, to the greatest extent possible, the reduction in reflective capacity caused by the constant passage of tires over the glass beads in question.

Use of glass particles to impart reflectivity to surfaces in general has also been previously described.

US patent 6,447, 595 issued to Greco describes the addition of fine particles such as glass beads for enhancing the appearance of paint on consumer goods. Greco specifically teaches the use of coated glass chips with an essentially random geometrical shape and a size less than about 100 microns. Thus, like the LaRoche and Goeb references cited above, Greco teaches against the use of untreated (i. e. uncoated) glass particles.

US patent application 20020090515 filed by Pellerite et al. is another example of surface treatment for glass particles. Thus, like the LaRoche, Goeb and Greco references cited above, Pellerite teaches against the use of untreated (i. e. uncoated) glass particles.

US patent application 20020119302 filed by Fritz teaches a coating composition which"... broadly comprises glass material having an irregularly- shaped particle geometry (the particulate glass material also referred to herein

by the term"randomly shaped glass chips"or simply"randomly shaped chips") which is dispersed in a carrier. In accordance with an advantageous embodiment of the invention, particularly from an environmental standpoint, the glass material comprises finely divided fragments of recycled glass in the form of randomly shaped chips. "Thus Fritz teaches that use of spherical glass beads is undesirable as a means of imparting reflective properties to a surface.

See also US patent 5,593, 772 issued to Zamot, described hereinbelow, which briefly mentions that glass particles are reflective.

Reflectivity may also be imparted to a variety of surfaces by use of reflective adhesive labels, such as those produced by 3M Inc. and marketed under the trade name"Scotchlite". These reflective adhesive labels employ reflective particles sandwiched between a paper backing and a transparent plastic covering layer. As a result, their outer surface is smooth. These reflective adhesive labels have, as an inherent disadvantage, a tendency to lose their reflective power when installed outdoors due to adherence of airborne particles (e. g. dust or particulate vehicular exhaust) or of waterborne particles (e. g. dust in raindrops or mud splashed by passing wheels) to their transparent plastic covering layer.

Reflectivity may also be imparted to a variety of surfaces by use of plastic reflectors. These plastic reflectors have an inherent fragility which renders them ill suited to use in violent environments, such as along a roadway.

In cases where they are employed in violent environments, high maintenance costs and/or reduced performance over time are to be anticipated. Further, these plastic reflectors have a smooth outer surface. Thus these plastic reflectors have, as an inherent disadvantage, a tendency to lose their reflective power when installed outdoors as described hereinabove for reflective adhesive labels.

Use of special paints/coatings to prevent adhesion to surfaces has also been previously described.

US patent application 20020086142 filed by Ewings et al describes an adhesive/sealant compound with glass"microballoons"on the outer surface in

order to reversibly detackify the outer surface of the sealant. Ewings specifically teaches that the future adhesive capabality of the adhesive/sealant is not adversely affected by the glass microballooons.

US patent 5,039, 745 issued to Riddle describes a paint composition for protecting surfaces from vandalism such as graffiti or self-stick labels. Riddle purports to achieve"... a non-stick surface that self-stick labels will not stay on, or can be easily removed and peeled therefrom. "By employing a paint formulation including a silicone resin, a polytetrafluoroethylene polymer, and a polyurethane polymer. Riddle teaches that previously attempted use of plastic particles to achieve a similar goal rendered the painted surface"... bumpy and easy to scratch." US patent 5,593, 772 issued to Zamot is a process of painting walls in order to reduce visualization of graffiti or other imperfections. Zamot mentions that glass beads could be added to the multicolor paint in order to make it reflective. Zamot fails to teach that inclusion of glass beads would make papers pasted or glued to treated walls easier to removing, teaching repainting instead.

There is thus a widely recognized need for, and it would be highly advantageous to have, improved roughened metal surfaces and methods of production thereof devoid of the above limitation (s).

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a reflective area of a metal workpiece. The reflective area includes: (a) a designated area of a surface of the metal workpiece; (b) a layer of liquid bonding media applied to the designated area and having an average thickness in the range of 58Fm to 72 Fm ; and (c) a plurality of untreated glass particles.

Each of the untreated glass particles has a size in the range of I60Fm~to 600ilm and the plurality of particles are applied to a surface of the liquid bonding media so that at least a portion of the plurality of the particles adheres to a surface of the liquid bonding media. The liquid bonding media is cured to

form a connective layer which adheres the at least a portion of the plurality of untreated glass particles to the designated area thereby rendering the designated area reflective to incident light.

According to another aspect of the present invention there is provided a method of imparting reflectivity to at least a portion of a metal workpiece. The method includes: (a) pretreating the metal workpiece (b) covering the pre- treated area with a layer of liquid bonding media characterized by an average thickness in the range of 581lm to 72 Fm ; and (c) contacting a plurality of untreated glass particles with a surface of the liquid bonding applied to the pre- treated surface. The particles have sizes in the range of 160} im to 6001lm and are applied to a surface of the liquid bonding media so that at least a portion of the plurality of the particles adheres to the surface of the liquid bonding media.

'Pretreating includes (i) choosing a designated area on a surface of the metal workpiece to which reflectivity is to be imparted; (ii) mechanically abrading the designated area; and (iii) applying an aqueous chromate solution to the designated area; (iv) evaporating water from the aqueous chromate solution. As a result, a pre-treated area is formed. The liquid bonding media solidifies to form a connective layer which adheres the at least a portion of the plurality of untreated glass particles to the designated area thereby rendering the designated area reflective to incident light.

According to yet another aspect of the present invention there is provided a method of reducing a degree of adherence of a handbill to at least a portion of a metal workpiece. The method includes: (a) pretreating the metal workpiece (b) covering the pre-treated area with a layer of liquid bonding media characterized by an average thickness in the range of 58Fm to 72 llm ; and (c) contacting a plurality of untreated glass particles with a surface of the liquid bonding applied to the pre-treated surface. The particles have sizes in the range of 160tm to 6001lm and are applied to a surface of the liquid bonding media so that at least a portion of the plurality of the particles adheres to the surface of the liquid bonding media.

Pretreating includes (i) choosing a designated area on a surface of the metal workpiece to which reflectivity is to be imparted; (ii) mechanically abrading the designated area; and (iii) applying an aqueous chromate solution to the designated area; (iv) evaporating water from the aqueous chromate solution; so that a pre-treated area is formed.

The liquid bonding media solidifies to form a connective layer which adheres the at least a portion of the plurality of untreated glass particles to the designated area thereby reducing a degree of adherence of a handbill applied to the designated area.

According to further features in preferred embodiments of the invention described below, the designated area is a pre-treated area of the metal workpiece formed by choosing the designated area, mechanically abrading the designated area ; subsequently applying an aqueous chromate solution to the designated area and evaporating water from the aqueous chromate solution.

According to still further features in the described preferred embodiments the metal workpiece is selected from the group consisting of a galvanized metal workpiece, an aluminum workpiece and a stainless steel workpiece.

According to still further features in the described preferred embodiments the liquid bonding media is selected from the group consisting of a polyester powder coat, a polyester paint, PVDF and a polyurethane paint.

According to still further features in the described preferred embodiments the untreated glass particles are approximately spherical.

According to still further features in the described preferred embodiments the metal workpiece is a folded metal sheet designed and constructed for use as a functional portion of a guardrail in proximity to a border of an area traveled by motor vehicles.

According to still further features in the described preferred embodiments a plurality of the folded metal sheets are assembled to construct the guardrail.

According to still further features in the described preferred embodiments the metal workpiece is an essentially flat sheet.

According to still further features in the described preferred embodiments the flat sheet is mountable upon a concrete partition.

According to still further features in the described preferred embodiments the metal workpiece is a vertical post.

According to still further features in the described preferred the liquid bonding media includes a color so that a reflective portion of the incident light has an appearance of the color.

According to still further features in the described preferred embodiments the choosing the designated area on the surface of the metal workpiece to which reflectivity is to be imparted includes consideration of a set of environmental conditions in which the workpiece will eventually be deployed and how the choosing can serve to at least partially protect the designated area reflective to incident light from the set of environmental conditions.

According to still further features in the described preferred embodiments the liquid bonding media solidifies as a result of curing.

According to still further features in the described preferred embodiments the curing includes heating the applied bonding media to a temperature of at leastl75°C.

According to still further features in the described preferred embodiments the curing includes heating the applied bonding media to a temperature which does not exceed 220°C.

According to still further features in the described preferred embodiments, a robotic device is employed to accomplish at least a portion of the claimed method.

The present invention successfully addresses the shortcomings of the presently known configurations by providing a reflective area of a metal workpiece and method of producing same which employ untreated glass

particles. The invention further provides an improved surface with reduced adhesiveness for handbills.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings: FIGs. 1 a-d illustrate a sequences of processes associated with reflectorizing a portion of a galvanized metal workpiece according to the present invention.

FIGs. 2 a-e are cross sectional views of reflectorized portions of metal workpieces according to various preferred embodiments of the present invention.

FIG. 3 is a simplified flow diagram illustrating a sequence of events associated with performance of preferred methods according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is of improved roughened metal surfaces and methods of production thereof that can be used to impart reflectivity and/or to prevent vandalism.

Specifically, the present invention can be used to produce reflective guardrails and signposts. Further, the present invention may serve to prevent posting of unwanted handbills, or to make their removal easier.

The principles and operation of improved roughened metal surfaces and methods of production according to the present invention may be better understood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways.

Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Referring now to the drawings, Figures 1 a-d illustrate, in cross-section, essential components of a reflective area 38 of a galvanized metal workpiece 20. Reflective area 38 includes a designated area 22 of a surface 24 of metal workpiece 20, a layer of liquid bonding media 26 applied to designated area 22 and a plurality of untreated glass particles 28 adhered to a surface 30 of bonding media 26. Bonding media 26 is preferably applied as a layer with an average thickness in the range of 581lm to 72 Am. Preferably, each of the untreated glass particles 28 has a size in the range of 160um to 600Fm. The plurality of particles 28 are applied to surface 30 of liquid bonding media 26 so that at least a portion of plurality of particles 28 adheres to surface 30 of liquid bonding media 26. Bonding media 26 is cured to form a connective layer which adheres untreated glass particles 28 to designated area 22 thereby rendering it reflective to incident light. Particles 28 may be, for example, commercially available particles such as VIALUX 20 particles (Sovitec S. A.; Fleurus; Belgium) or similar.

Designated area 22 of galvanized metal workpiece 20 is preferably pre- treated area by choosing designated area 22, mechanically abrading 46 (see

Figure 3) designated area 22, subsequently applying 48 an aqueous chromate solution to designated area 22 and evaporating water from the aqueous chromate solution. Mechanical abrasion preferably remove a portion (e. g.

10Am) of galvanization layer 21 from underlying metal 23 as illustrated in figure lb. Optionally, but preferably, the applied aqueous chromate solution is a non-rinsing solution.

According to various preferred embodiments of the invention, liquid bonding media 26 may be, for example, a polyester powder coat, a polyester paint, PVDF or a polyurethane paint.

Commercially available polyester powder coats such as BECKRYPOL BF3 manufactured by Dupont Powder Coatings (Montbrison, France) or similar may be employed in the context of the present invention according to manufacturers instructions.

Commercially available polyester paint (e. g. polyester 653 RC; Univercol Hillel Hoffman and Sons, Netanya, Israel) PVDF and polyurethane paint (e. g. Unicryl polyurethane acrylic (e. g. polyester 653 RC; Univercol Hillel Hoffman and Sons, Netanya, Israel) or similar may be employed in the context of the present invention.

According to alternate preferred embodiments of the invention, liquid bonding media 26 may be a thermoplastic applied as a layer of 150 microns or more : The high density thermoplastics tends to prevent entry of the particles 28 so that particles 28 will protrude from bonding media 30 to a similar degree as with the thinner layers described hereinabove.

Regardless of the exact composition of bonding media layer 26, the combination of chromate solution pretreatment and application of bonding layer 26 insure surface 24 of workpiece 20 covered by reflective area 38 is significantly more resistant to oxidation, corrosion and UV damage than the remainder of workpiece 20.

According one preferred embodiment of the invention, untreated glass particles 28 are approximately spherical. For purposes of this specification and

the accompanying claims"approximately spherical"indicates particles resulting from an industrial process which is intended to produce rounded particles, spheres or microballoons. It will be appreciated that some variation from perfect spheres is inherent in such processes. However, deviations from spherical, which are inherent results of the relevant manufacturing processes are included within"approximately spherical"as used in this specification and the accompanying claims.

According to still further features in the described preferred embodiments metal workpiece 20 is a folded metal sheet designed and constructed for use as a functional portion of a guardrail in proximity to a border of an area traveled by motor vehicles (e. g. road, bridge, parking lot or freeway interchange).

Referring now to Figures 2a-e, the versatility of the present invention in marking roadways will be explained in greater detail. These figures show cross-sections of various embodiments of the invention.

Figure 2a illustrates reflective area 38 applied to surface 24 of workpiece 20. This embodiment of the invention is suited for use with concrete guardwalls (e. g. California walls) as well as use in conjunction with any non- metal surface.

Figures 2 b and 2 c illustrate"W"and"M"cross-section guardrails which are commonly use along highways in the United States-and Europe respectively. According to these embodiments of the invention, reflective area 38 is situated in a recessed area 25 of workpiece 20. Thus, choosing the designated area 22 on surface 24 of metal workpiece 20 to which reflectivity is to be imparted includes consideration of a set of environmental conditions in which the workpiece will eventually be deployed and how the choosing can serve to at least partially protect the designated area reflective to incident light from the set of environmental conditions. In this case, recessed areas 25 are partially protected from rain, splashed mud, and airborne particulate matter which might otherwise accumulate on reflective surface 38 to a greater degree.

Further, recessed areas 25 are serve to protect reflective surface 38 from damage which might be caused by vehicular impact to some dgree.

Figure 2d illustrates a cross section of a hexagonal pole including 6 concave faces. Recessed areas 25 of surface 24 are covered by reflective surfaces 38 as described hereinabove. Protection from environmental factors is as described hereinabove. This embodiment is suitable for imparting increased visibility to utility poles or light poles. While a hexagonal configuration is depicted, any polygonal cross-section may be similarly constructed. Further, while concave faces are pictured, flat or convex faces might bear reflective surface 38. Thus, according to additional embodiments of the invention, poles with round, oblong or polygonal cross sections and reflective surfaces 38 are provided.

Figure 2e illustrates a signpost which incorporates reflective surface 38 of the present invention. Holes 27 at regular intervals along the height of the post facilitate attachment of signs, for example using bolts or rivets.

Optionally, but most preferably, a plurality of the folded metal sheets (e. g. those depicted in figures 2b or 2c) are assembled end to end to construct a guardrail. This creates an uninterrupted reflective surface 38 along the length of a roadway. Reflective surface 38 is inherently deployed at an optimum height to reflect incident light from headlights of vehicles. Alternately, but also preferably, folded metal sheets (e. g. those depicted in figures 2b or 2c) are assembled end to end to construct a guardrail in which reflective surfaces 38 occur periodically. This may be achieved, for example by alternating sheets with reflective surface 38 and sheets without reflective surface 38.

According some preferred embodiments of the invention, liquid bonding media 26 includes a color so that a reflected portion of the incident light has an appearance of the color. For example, guardrails along the shoulder of the road feature a white bonding layer 26, guardrails along the midline of the road feature a yellow bonding layer 26, guardrails traversing a road end (e. g. at a

"T"intersection or a dead end) feature a red bonding layer 26 and police barricades feature a blue bonding layer 26.

Alternately, or additionally, colored glass particles 28 may be employed to impart a color to reflected light.

The present invention is further embodied by a method 40 of imparting reflectivity to at least a portion of metal workpiece 20. Method 40 includes pretreating 42 workpiece 20, covering 50 pre-treated area 22 with a layer of liquid bonding media 26 characterized by an average thickness in the range of 58plm to 72 Am and contacting 52 a plurality of untreated glass particles 28 with surface 30 of bonding media 26 applied to pre-treated surface 22.

Particles 28 are preferably in the range of 160 u. m to 600 Am in size and are applied to surface 30 of liquid bonding media 26 so that at least a portion of particles 28 adheres to surface 30 of liquid bonding media 26.

Pretreating may includes, for example, choosing 44 designated area 22 on surface 24 of metal workpiece 20 to which reflectivity 38 is to be imparted, mechanically abrading 46 designated area 22, applying 48 an aqueous chromate solution to the designated area and evaporating water from the aqueous chromate solution so that a pre-treated area 22 is formed. Liquid bonding media 26 solidifies 54 to form a connective layer which adheres the at least a portion of the plurality of untreated glass particles 28 to designated area 22 thereby rendering designated area 22 reflective 28 to incident light.

Preferably, method 40 accomplished in a workshop or factory.

Alternately, method 40 may be practiced on, for example, assembled guardrails along a highway. One ordinarily skilled in the art of robotics will be able to design and built a robotic device capable of executing method 40.

The phrase"mechanically abrading"as used in this specification and the accompanying claims includes, but is not limited to, sand blasting, grit blasting, shot blasting, application of abrasive brushes, application of abrasive paper, application of abrasive cloth and application of an abrasive wheel.

Preferably, choosing 44 designated area 22 on surface 24 of metal workpiece 20 to which reflectivity 38 is to be imparted includes consideration of a set of environmental conditions in which workpiece 20 will eventually be deployed and how the choosing can serve to at least partially protect designated area 22 reflective 38 to incident light from the set of environmental conditions as detailed hereinabove.

Preferably, liquid bonding media 26 solidifies 54 as a result of curing 56. Exact curing conditions will be a function of a number of factors including, but not limited to, the specific bonding media 26 employed, the type of furnace used for heating, metal thickness of workpiece 20, metal type and the inverse relationship between time required and applied temperature.

Thus, curing may include, for example, heating applied bonding media 26 to a temperature of at least 175°C if bonding media 26 is a polyester paint.

Typically, a curing time of 10 minutes or more is optimal in this case Thus, curing may include, for example, heating applied bonding media 26 to a temperature of about 220°C if bonding media 26 is a powder coat Typically, a curing time of 12 minutes or more is optimal in this case.

Method 40 may also be advantageously employed to reduce a degree of adherence of a handbill to at least a portion of a metal workpiece. Practice of method 40 as described hereinabove produces a surface roughened by untreated glass 28 particles adhering to designated area 22 thereby reducing a degree of adherence of a handbill applied to designated area 22.

For purposes of this specification and the accompanying claims, the term"handbill"refers to any paper or cloth affixed to a surface without permission of an owner of the surface. Therefore, handbill includes, but is not limited to an advertisement, an announcement, an invitation and a picture.

Affixation of handbills may be by use of liquid glue or paste applied with a brush or squeegee, or by use of adhesive paper. The present invention reduces the adherence of a handbill irrespective of the method of affixation.

Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting.

Additionally, each of the various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below finds experimental support in the following examples.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference.

In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.