WO1997031357A1 - Dew-resistant retroreflective traffic sign having a textured glass surface - Google Patents
Dew-resistant retroreflective traffic sign having a textured glass surface Download PDFInfo
- Publication number
- WO1997031357A1 WO1997031357A1 PCT/US1997/000628 US9700628W WO9731357A1 WO 1997031357 A1 WO1997031357 A1 WO 1997031357A1 US 9700628 W US9700628 W US 9700628W WO 9731357 A1 WO9731357 A1 WO 9731357A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- retroreflective
- dew
- sign
- graphic
- glass
- Prior art date
Links
- 239000011521 glass Substances 0.000 title claims abstract description 93
- 238000004519 manufacturing process Methods 0.000 claims abstract description 4
- 239000000758 substrate Substances 0.000 claims description 21
- 239000000853 adhesive Substances 0.000 claims description 18
- 230000001070 adhesive effect Effects 0.000 claims description 18
- 239000011229 interlayer Substances 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000003892 spreading Methods 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 4
- 239000012298 atmosphere Substances 0.000 claims description 3
- 239000008367 deionised water Substances 0.000 claims description 2
- 229910021641 deionized water Inorganic materials 0.000 claims description 2
- 238000007639 printing Methods 0.000 claims description 2
- 239000005361 soda-lime glass Substances 0.000 claims description 2
- 229920000620 organic polymer Polymers 0.000 claims 1
- 239000004590 silicone sealant Substances 0.000 claims 1
- 239000000463 material Substances 0.000 description 18
- 239000010410 layer Substances 0.000 description 17
- -1 alkoxy compound Chemical class 0.000 description 15
- 239000005357 flat glass Substances 0.000 description 12
- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- 239000012790 adhesive layer Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 6
- 229920000642 polymer Polymers 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 4
- 241000237503 Pectinidae Species 0.000 description 4
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 4
- 229910003460 diamond Inorganic materials 0.000 description 4
- 239000010432 diamond Substances 0.000 description 4
- 239000010408 film Substances 0.000 description 4
- 238000005338 heat storage Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 4
- 239000004926 polymethyl methacrylate Substances 0.000 description 4
- 235000020637 scallop Nutrition 0.000 description 4
- 238000005299 abrasion Methods 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 239000011120 plywood Substances 0.000 description 3
- 229920001296 polysiloxane Polymers 0.000 description 3
- 235000013175 Crataegus laevigata Nutrition 0.000 description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000006096 absorbing agent Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 125000001931 aliphatic group Chemical group 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 150000001565 benzotriazoles Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000008119 colloidal silica Substances 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 230000003292 diminished effect Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000005338 frosted glass Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000000976 ink Substances 0.000 description 2
- 239000003550 marker Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920000058 polyacrylate Polymers 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920006254 polymer film Polymers 0.000 description 2
- 239000013047 polymeric layer Substances 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004800 polyvinyl chloride Substances 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- KJYSXRBJOSZLEL-UHFFFAOYSA-N (2,4-ditert-butylphenyl) 3,5-ditert-butyl-4-hydroxybenzoate Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC=C1OC(=O)C1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 KJYSXRBJOSZLEL-UHFFFAOYSA-N 0.000 description 1
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 description 1
- 241000282994 Cervidae Species 0.000 description 1
- FBPFZTCFMRRESA-FSIIMWSLSA-N D-Glucitol Natural products OC[C@H](O)[C@H](O)[C@@H](O)[C@H](O)CO FBPFZTCFMRRESA-FSIIMWSLSA-N 0.000 description 1
- 229940123457 Free radical scavenger Drugs 0.000 description 1
- 239000004831 Hot glue Substances 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000012965 benzophenone Substances 0.000 description 1
- 150000008366 benzophenones Chemical class 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 229920001038 ethylene copolymer Polymers 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000004811 fluoropolymer Substances 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 230000005660 hydrophilic surface Effects 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920002959 polymer blend Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000002516 radical scavenger Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000000600 sorbitol Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F13/00—Illuminated signs; Luminous advertising
- G09F13/02—Signs, boards, or panels, illuminated by artificial light sources positioned in front of the insignia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
- B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
- B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
- B32B17/10009—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets
- B32B17/10036—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing characterized by the number, the constitution or treatment of glass sheets comprising two outer glass sheets
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
- E01F9/00—Arrangement of road signs or traffic signals; Arrangements for enforcing caution
- E01F9/60—Upright bodies, e.g. marker posts or bollards; Supports for road signs
- E01F9/604—Upright bodies, e.g. marker posts or bollards; Supports for road signs specially adapted for particular signalling purposes, e.g. for indicating curves, road works or pedestrian crossings
- E01F9/619—Upright bodies, e.g. marker posts or bollards; Supports for road signs specially adapted for particular signalling purposes, e.g. for indicating curves, road works or pedestrian crossings with reflectors; with means for keeping reflectors clean
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F13/00—Illuminated signs; Luminous advertising
- G09F13/04—Signs, boards or panels, illuminated from behind the insignia
- G09F13/0418—Constructional details
- G09F13/0472—Traffic signs
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
- G09F13/00—Illuminated signs; Luminous advertising
- G09F13/16—Signs formed of or incorporating reflecting elements or surfaces, e.g. warning signs having triangular or other geometrical shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/40—Properties of the layers or laminate having particular optical properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2315/00—Other materials containing non-metallic inorganic compounds not provided for in groups B32B2311/00 - B32B2313/04
- B32B2315/08—Glass
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2590/00—Signboards, advertising panels, road signs
Definitions
- roadway traffic signs In order to be effective, roadway traffic signs must be visible to motor vehicle drivers at night as well as during the day. Because it is impractical to illuminate all traffic signs with external lighting, a common approach to enhancing the visibility of roadway traffic signs is to use retroreflective graphics on the traffic sign.
- Retroreflective signs have the unique ability to return a substantial portion of incident light back toward the light source. At nighttime, light from motor vehicle headlights strikes the retroreflective graphics and is retroreflected to the motor vehicle driver. The bright image displayed by the retroreflective sign makes the sign easier to read and gives motorists more time to react.
- a significant problem that has been encountered with retroreflective traffic signs is the accumulation of water droplets on the surface of the signs.
- Dew is an especially common source of water droplets and can be particularly problematic because it occurs predominantly at nighttime when the retroreflective signs are operative.
- dew can seriously disrupt the path of incident and retroreflected light. This can make information on traffic signs much more difficult for passing motorists to read.
- This problem is very well known, and there have been a variety of attempts aimed at removing dew or preventing dew from forming on the surface of traffic signs.
- German Patent No. 4226266 to Gubela discloses an electrical heating element placed behind the retroreflector.
- Technonijuichi K K. discloses an anti-dew reflective road traffic sign that has a heat storage container tightly bonded to its back side.
- the heat storage container contains a heat storage agent, typically a gel containing a liquid glycol that collects heat and radiates that heat towards the sign's front surface.
- U.S. Patent No. 5,087,508 to Beck discloses a retroreflective traffic sign having a thermal reservoir layer located behind the retroreflective surface.
- the thermal reservoir contains a material that undergoes a phase change between - 20°C and 40°C. The energy barrier of the phase transition prevents the sign from cooling rapidly.
- Instrument Mfg. Co. discloses an anti-fog mirror in which a vibration generator is attached to the rear surface of a mirror.
- Japanese Patent Application 07259024A assigned to Matsushita Denki Sangyo KK discloses an anti-fog mirror for road safety in which solar energy is stored in a heater unit located behind the mirror's surface.
- Another method that has been used to impart anti-dew characteristics to retroreflective traffic signs is to apply a water-spreading, hydrophilic coating to the surface of the sign.
- the hydrophilic coating spreads the moisture over the sign's surface and thus makes the sign easier to read because the resulting thin water layer does not alter the path of incident and retroreflective light to as great an extent.
- U.S. Patent Nos. 5,073,404, 4,844,976 and 4,755,425 to T. Huang disclose a retroreflective sheeting that has a transparent coating comprising colloidal silica and a polymer selected from aliphatic polyurethanes, polyvinylchloride co-polymers and acrylic polymers.
- the colloidal silica is disposed in the polymer at about 10-80 weight % (10-70 weight % in the case of polyacrylates).
- the transparent coatings provide superior dew repellency, allowing the retroreflective sheeting to retain a higher percentage of its original brightness after being exposed to moisture.
- traffic signs are not disposed on road surfaces, and, as a consequence, do not require the extreme abrasion resistance that is required of pavement markers.
- loss of intensity caused by precipitation, especially dew is of great concern.
- the present invention provides an anti-dew retroreflective sign comprising a glass plate having a textured outer surface disposed over a retroreflective graphic.
- the textured glass surface is exposed to air, and, in dew conditions, spreads precipitation in a thin film over the glass plate's surface.
- the present invention also provides a method for making an anti-dew retroreflective sign in which a glass plate having a textured outer surface is placed over the retroreflective graphic.
- the present invention provides an economical and elegantly simple method of making an anti-dew retroreflective traffic sign.
- the anti-dew characteristics of the inventive retroreflective traffic sign are achieved without the need for electrical inputs, heating elements, heat storage layers, infrared beam radiators, phase transition materials or vibration generators.
- Other advantages provided by the textured glass surface include: resistance to organic solvents, thus facilitating removal of graffiti from the sign; weathering resistance; and protection from ultraviolet (UV) light, thus extending the lifetime of underlying polymers and inks.
- FIG. 1 is a front view of a retroreflective sign of the present invention in which the retroreflective graphic is "St. Paul 10 km".
- FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.
- FIG. 3 is a plot of light intensity versus time of day from retroreflective sheeting having a flat glass surface.
- FIG. 4 is a plot of light intensity measured versus time of day from retroreflective sheeting having a textured glass surface.
- FIG. 5 is an SEM photomicrograph of the surface of a flat glass plate.
- FIG. 6 is an SEM photomicrograph of the surface of a textured glass plate.
- FIG. 7 is an SEM photomicrograph of the surface of a highly textured glass plate.
- a retroreflective sign 2 of the present invention contains information in the form of a retroreflective graphic 3.
- the retroreflective graphic is in the form of lettering that spells "St. Paul 10 km".
- the retroreflective graphic 3 is disposed on substrate 4.
- An interlayer 5 overlies the retroreflective graphic 3.
- outer layer lies a glass sheet 6 having one major glass surface 7 that faces the substrate and a second major textured glass surface 8 that is exposed to the atmosphere.
- Retroreflective graphics of the present invention are defined as retroreflective sheeting or retroreflective elements arranged in the form of characters, numbers or symbols. Retroreflective graphics do not include a uniform retroreflective sheeting or layer over the entire surface. Thus, graphics are not merely plain reflectors such as a pavement marker; however, the retroreflective graphics can be disposed over a uniform retroreflective background.
- the retroreflective graphics can also be an inverse design such as a retroreflective background for non-retroreflective characters, numbers or symbols such as a non-reflective profile of a cow or deer. In the latter case, the retroreflective graphic would include both the retroreflective background and the non-reflective profile.
- the retroreflective graphic 3 is typically bonded to the substrate 4 or to a background material by an adhesive or by mechanical means such as anodized aluminum rivets. Adhesives are preferred, and pressure sensitive adhesives are especially preferred.
- the retroreflective characters, numbers or symbols can be bonded to a retroreflective background. For example, the retroreflective characters, numbers or symbols can be cut from white retroreflective sheeting and bonded to a background of retroreflective sheeting that has been overlaid with a clear, colored polymer film such as an acrylic film. Common background colors are green, brown or blue.
- retroreflective graphic Another way of making the retroreflective graphic is to cut out letters, numerals or symbols from a transparent colored polymer film, and laminate the colored letters, numerals or symbols onto white retroreflective sheeting.
- a suitable, commercially available clear colored acrylic film is ScotchliteTM Electronic Cuttable Film Series 1170, available from 3M, St. Paul, MN.
- the retroreflective graphic can be produced by printing over portions of a retroreflective sheet.
- a stop sign graphic can be made by screen printing a red clear ink with a negative legend on a white retroreflective sheeting.
- the retroreflective graphics typically contain retroreflective sheeting.
- retroreflective sheeting examples include ScotchliteTM Reflective Sheeting High Intensity Grade Series 3870, ScotchliteTM Reflective Sheeting Diamond Grade VLP Series 3990, and ScotchliteTM Reflective Sheeting Diamond Grade LDP Series 3970, available from 3M, St. Paul, Minnesota.
- Retroreflective sheeting typically comprises a reflective surface and optical elements. The reflective surface serves to reflect incident light, and the optical elements serve to redirect the incident light toward the light source.
- the reflective material may comprise a specular metal reflector such as aluminum or silver (see, for example, U.S.
- Patent No. 5,283,101 or a diffuse reflector such as a heavy metal pigment or a polymeric material wherein reflectance is caused by a difference in refractive indices at an interface (frequently a plastic-air interface).
- Optical elements typically come in one of two forms: beaded lens elements and cube corner elements. Examples of retroreflective sheeting that employ beaded lens elements have been disclosed in U.S. Patent Nos. 2,407,680, 3,190,178, 4,025,159, 4,265,938, 4,664,966, 4,682,852, 4,767,659, 4,895,428, 4,896,943, 4,897,136, 4,983,436, 5,064,272 and 5,066,099.
- the substrate 4 is typically a metallic, wooden or polymeric material.
- the substrate is a rigid material, with aluminum being the most common.
- the substrate may also be a flexible polymeric material or a combination in which a flexible polymeric material is mounted onto a rigid material such as aluminum or plywood.
- the substrate is usually preferred to be opaque.
- Typical examples of commercially available substrates include: a 2 mm (millimeters) thick acid etched and degreased aluminum panel, a high density 2 cm (centimeters) thick plywood, or a 4 mm thick fiberglass- reinforced plastic panel; all these substrates are commonly used in traffic sign industries and are available from the Lyle Sign Company, Eden Prairie, MN.
- retroreflective signs of the present invention can be produced without a substrate.
- the retroreflective sign would be comprised of a textured glass sheet attached to the retroreflective graphic.
- the glass sheet is attached to the retroreflective graphic by a clear adhesive.
- a clear pressure sensitive adhesive with releasable liner is attached to the back of the retroreflective graphic.
- Release liners are typically sheets of a non-stick polymer such as a fluoropolymer or a silicone-treated polyethylene, polypropylene, poly(ethylene terephthalate), etc.
- the retroreflective sign can subsequently be mounted onto a rigid substrate.
- the retroreflective graphic and textured glass plate (with or without an adhesive layer) can be mounted in a frame.
- the retroreflective sign of the present invention further contains an interlayer 5 over the retroreflective graphics.
- the interlayer may be any light-transmissible layer.
- the interlayer comprises an adhesive that bonds the retroreflective graphic and the glass plate.
- the interlayer comprises an air gap.
- the interlayer may also comprise a polymeric material.
- One preferred polymeric material is poly(methyl methacrylate).
- polystyrene resin examples include: aliphatic polyurethane, (meth)acrylic acid and ethylene copolymers, or a flexible poly( vinyl chloride).
- the polymeric material may also be a copolymer, polymer blend, or a multilayer film.
- the polymeric material is preferably transparent and will transmit more than 80% of the incident visible light; more preferably more than 90%.
- the polymeric material may contain UV absorbers and free radical scavengers. Common examples of such additives include hindered amines, benzophenones, benzotriazoles, oxanilides and arylbenzoates.
- Examples of commercially available hindered amines include Chimassorb(TM) 944, Tinuvin(TM) 144, 622, and 770 available from Ciba- Geigy Corp., Hawthorne, New York.
- Common examples of UV absorbers are benzotriazoles, such as Tinuvin(TM) 327, 328, 1 130, or P, available from Ciba- Geigy Co ⁇ ., Hawthorne, New York; oxanilides, such as Sanduvor(TM) EPU or VSU, available from Sandoz Chemicals Co ⁇ ., Charlotte, North Carolina; and arylbenzoates, such as UV-Chek AM-340, available from Ferro Co ⁇ ., Cleveland, Ohio.
- the polymeric layer may also contain coloring agents or fluorescent compounds for manufacturing various colored such as yellow, orange, brown, green, blue, fluorescent orange or yellow-green retroreflective sheetings.
- the polymeric layer is preferably about 0.05 to 2.5 mm thick.
- the glass plate 6 is a silica-based glass, preferably soda-lime glass.
- the glass plate can not be an organic polymeric material. It has been discovered that organic polymeric materials (with or without textured surfaces), such as poly(methyl methacrylate), do not provide the full range of desirable characteristics including anti-dew properties, durability, weatherability (e.g., resistance to microbes), resistance to organic solvents, etc. that are provided by the textured glass plates of the present invention.
- the glass plate is light transmissible, and preferably capable of transmitting at least 80%, more preferably 90%, of the intensity of visible light pe ⁇ endicularly incident to the glass plate.
- the thickness of the glass plate is preferably 0.1 to 10 mm; more preferably 0.5 to 6 mm; and still more preferably 1 to 4 mm.
- the glass plate has two major surfaces.
- the outer major surface of the glass plate is exposed to the air.
- the outer surface is a textured glass surface having microscopic surface variations of at least about 3 nm (nanometer).
- the textured surfaces are preferably defined as containing micropores having diameters in the size range of between about 0.003 to 10 ⁇ m (micrometers), more preferably between about 0.005 to 1 ⁇ m, still more preferably between about 0.01 to 0.5 ⁇ m, and even more preferably between about 0.01 and 0.05 ⁇ m.
- Figs. 5-7 show scanning electron microscope (SEM) photomicrographs of three different glass surfaces.
- Fig. 5 shows an untextured, flat glass surface which appears featureless under SEM analysis.
- Fig. 6 shows a textured glass surface with micropores having diameters in the size range of about 10 to 60 nm (the size scale is shown in the lower right hand corner of each photomicrograph).
- Fig. 7 shows a more highly textured glass surface; the surface of this glass appears frosted when viewed by the unaided eye.
- the texturing can be either patterned or random, but is preferably random (i.e., is without a regular pattern).
- the textured glass has the characteristics of scallops, islands and micropores described in U.S. Patent No. 4,944,986, inco ⁇ orated herein by reference.
- the scallops are generally in the range of 100 to 2,000 ⁇ m.
- the islands are in the range of 10 to 120 ⁇ m. These scallops and islands tend to diffuse the incoming visible light.
- the etched glass should have fewer scallops and islands, but more of the microporous surface texture.
- the textured glass plate is AR glass purchased from Zuel Company, St. Paul, Minnesota.
- the textured glass surface may alternatively be defined by its water spreading properties.
- the static contact angle of deionized stationary water droplets on the textured glass surface at 25°C remains below 40°, more preferably less than 30°, and still more preferably less than 20°.
- Static contact angles can be measured on a deionized water droplet of 0.01 ml with a contact angle goniometer.
- At least the outer major surface 8 of the glass plate must be textured.
- the glass plate can be textured either before or after it is affixed to the sign.
- the surface of the glass can be textured by physical means such as grinding or sand blasting or by chemical means.
- the glass is etched with an acid, typically hydrofluoric acid.
- the glass is etched with an aqueous solution of hydrofluoric acid, ammonium bifluoride and a water-soluble organic compound such as sorbitol.
- the inner major surface of the glass 7 may be either smooth or textured. In a preferred embodiment, the inner surface is also textured in order to reduce cost or enhance transparency.
- the retroreflective signs of the invention may also include adhesive layers.
- the adhesive can serve to bond any of the layers in the sign.
- an adhesive layer may be disposed on the second major glass surface; thus, bonding the glass plate to the retroreflective graphic.
- the adhesive layer or layers can be continuous or noncontinuous.
- the noncontinuous layer or layers provide an air gap between layers.
- the major glass surface 7 is coated with a silane prior to contacting the adhesive (see U.S.
- An adhesive layer can also be disposed on the outer surface of the substrate (i.e., the major substrate surface facing away from the graphic).
- the substrate is preferably a flexible polymeric sheet.
- adhesive can be disposed on the rear of the retroreflective graphic or on the outer surface of the substrate and covered with a release liner made of a polymeric material such as silicone treated polyethylene.
- Types of adhesives usable in the retroreflective signs include, but are not limited to, hot melt and pressure sensitive adhesives.
- Foam adhesives are especially advantageous in those embodiments in which an adhesive is used to bond the retroreflective graphic to the substrate, since foam adhesives are likely to be more durable.
- Adhesives disclosed in U.S. Patent Nos. 4,906,523 and 5,264,063 may be used, and are inco ⁇ orated herein by reference.
- the signs can use mechanical means to attach the glass plate to the signs.
- suitable mechanical means include: clamps on the edges of the sign; a frame, preferably a heavy duty aluminum frame; or screws through the glass plate.
- gaskets or silicone sealer may be used around the edges of the sign to prevent moisture or contaminants from entering between any of the sign's layers.
- the retroreflective sign should retroreflect light efficiently.
- the retroreflective signs of the present invention retroreflect preferably at least 50%, more preferably at least 70%, and most preferably at least 90% of incident light as compared with retroreflective sheeting without a glass cover plate.
- Intensity of retroreflected light having an entrance angle of about 5° from the main axis pe ⁇ endicular to the test panel was measured using a retro-luminometer (model 1980A Spectra Pritchard) at an angle about 0.2° off from the light source (i.e., a 0.2° observation angle).
- the light source was a 500 watt floodlamp.
- Each test sign retroreflection was measured in a 10 minute interval from 6 p.m. to 6 a.m. the following day.
- Fig. 3 shows the measurement of the intensity of light retroreflected from sheeting with a flat glass cover plate.
- the flat glass plate was 2.4 mm (95 mil) thick, obtained from AFG Industries, Kingsport, Tennessee (average visible light transmittance of 91%).
- the initial intensity of retroreflected light was about 430 candelas per lux square meter (cd/lux m 2 ).
- Fig. 4 shows the measurement of intensity of light retroreflected from sheeting with a textured glass cover plate.
- the textured glass was 2.4 mm (95 mil) thick, textured glass obtained from Zuel Company, St. Paul, Minnesota (identified as AR glass).
- the formation of dew began to diminish the intensity of light retroreflected from the sheeting and by 10:00 p.m. the intensity of retroreflected light diminished to about 200 cd/lux/m 2 .
- intensity of retroreflected light then increased, and by about 12:30 a.m., retroreflected light had recovered to its initial intensity.
- the frosted glass cover plate showed a general decrease in intensity (to about 330 cd/lux/m 2 ) due to the frosted character, but showed excellent anti-dew properties that were very similar to the textured glass described above and in Fig. 4.
- Retroreflective sheeting without a cover plate or with a textured poly(methyl methacrylate) cover plate both showed a loss of intensity to about 50 cd/lux/m 2 and remained at about 50 cd/lux/m 2 through
- ScotchliteTM Reflective Sheeting Diamond Grade LDP No. 3970 Glass cover plates were laid over the sheeting, and the sheeting with plate was held by a frame. No adhesive was used. The results of these measurements are shown in Table 1.
- both flat glass and textured glass cover plates are acceptable in terms of the intensity of retroreflected light.
- Flat glass cover plates do not perform as well as textured glass plates because retroreflectivity appreciably declines under dew conditions (see, for example, FIG. 3).
- the frosted glass plate (i.e., textured RR glass) is acceptable for use on retroreflective traffic signs because of its good anti-dew properties. It, however, is less desirable than a less coarsely textured glass because of its reduced retroreflective intensity (see Table 1).
- flat glass and textured glass surfaces were analyzed by SEM. Samples of flat glass from AFC industries; textured AR glass from Zuel Company and textured RR glass from Zuel Company were vapor coated with a thin layer of platinum (less than 3.5 nm) by conventional techniques. The samples were then analyzed at 100,000X magnification using a Hitachi Model S-4500 Field Emission Scanning Electron Microscope. The resulting
- retroreflective signs of the present invention can be made with or without a polymeric interlayer or can include additional layers such as adhesive layers between the graphic and substrate or graphic and glass. It should therefore be understood that this invention is not unduly limited to the illustrative embodiments set forth above, but is to be controlled by the limitations set forth in the claims and equivalents thereof.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Geometry (AREA)
- Road Signs Or Road Markings (AREA)
- Optical Elements Other Than Lenses (AREA)
- Illuminated Signs And Luminous Advertising (AREA)
- Laminated Bodies (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9530147A JP2000505211A (en) | 1996-02-20 | 1997-01-16 | Dew-resistant retroreflective traffic signs with textured glass surfaces |
EP97902948A EP0882285A1 (en) | 1996-02-20 | 1997-01-16 | Dew-resistant retroreflective traffic sign having a textured glass surface |
AU17004/97A AU1700497A (en) | 1996-02-20 | 1997-01-16 | Dew-resistant retroreflective traffic sign having a textured glass surface |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60396796A | 1996-02-20 | 1996-02-20 | |
US08/603,967 | 1996-02-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997031357A1 true WO1997031357A1 (en) | 1997-08-28 |
Family
ID=24417631
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1997/000628 WO1997031357A1 (en) | 1996-02-20 | 1997-01-16 | Dew-resistant retroreflective traffic sign having a textured glass surface |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0882285A1 (en) |
JP (1) | JP2000505211A (en) |
KR (1) | KR19990087059A (en) |
CN (1) | CN1211332A (en) |
AU (1) | AU1700497A (en) |
CA (1) | CA2244922A1 (en) |
WO (1) | WO1997031357A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2782944A1 (en) * | 1998-09-09 | 2000-03-10 | Aerospatiale | DEVICE FOR LOCATING A BREAK IN A TRANSPARENT PANEL HAVING AT LEAST TWO PLIES AND A PANEL OBTAINED |
US6641767B2 (en) | 2000-03-10 | 2003-11-04 | 3M Innovative Properties Company | Methods for replication, replicated articles, and replication tools |
US8354160B2 (en) | 2006-06-23 | 2013-01-15 | 3M Innovative Properties Company | Articles having durable hydrophobic surfaces |
US9285584B2 (en) | 2010-10-06 | 2016-03-15 | 3M Innovative Properties Company | Anti-reflective articles with nanosilica-based coatings and barrier layer |
US9428654B2 (en) | 2004-04-15 | 2016-08-30 | Avery Dennison Corporation | Dew resistant coatings |
US9896557B2 (en) | 2010-04-28 | 2018-02-20 | 3M Innovative Properties Company | Silicone-based material |
US10066109B2 (en) | 2010-04-28 | 2018-09-04 | 3M Innovative Properties Company | Articles including nanosilica-based primers for polymer coatings and methods |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4596622A (en) * | 1979-10-05 | 1986-06-24 | Amerace Corporation | Method for making an abrasion-resistant reflective marker |
US4618518A (en) * | 1984-08-10 | 1986-10-21 | Amerace Corporation | Retroreflective sheeting and methods for making same |
US4944986A (en) * | 1988-09-23 | 1990-07-31 | Zuel Company | Anti-reflective glass surface |
US5213872A (en) * | 1991-04-19 | 1993-05-25 | Stimsonite Corporation | Preprinted retroreflective highway sign and method for making the sign |
-
1997
- 1997-01-16 KR KR1019980706445A patent/KR19990087059A/en not_active Application Discontinuation
- 1997-01-16 EP EP97902948A patent/EP0882285A1/en not_active Ceased
- 1997-01-16 AU AU17004/97A patent/AU1700497A/en not_active Abandoned
- 1997-01-16 CN CN97192323A patent/CN1211332A/en active Pending
- 1997-01-16 CA CA002244922A patent/CA2244922A1/en not_active Abandoned
- 1997-01-16 WO PCT/US1997/000628 patent/WO1997031357A1/en not_active Application Discontinuation
- 1997-01-16 JP JP9530147A patent/JP2000505211A/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4596622A (en) * | 1979-10-05 | 1986-06-24 | Amerace Corporation | Method for making an abrasion-resistant reflective marker |
US4618518A (en) * | 1984-08-10 | 1986-10-21 | Amerace Corporation | Retroreflective sheeting and methods for making same |
US4944986A (en) * | 1988-09-23 | 1990-07-31 | Zuel Company | Anti-reflective glass surface |
US5213872A (en) * | 1991-04-19 | 1993-05-25 | Stimsonite Corporation | Preprinted retroreflective highway sign and method for making the sign |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2782944A1 (en) * | 1998-09-09 | 2000-03-10 | Aerospatiale | DEVICE FOR LOCATING A BREAK IN A TRANSPARENT PANEL HAVING AT LEAST TWO PLIES AND A PANEL OBTAINED |
EP0985523A1 (en) * | 1998-09-09 | 2000-03-15 | AEROSPATIALE SOCIETE NATIONALE INDUSTRIELLE, Société Anonyme | Location device of a crash in a at least two layer transparent panel and obtained panel |
US6346314B1 (en) | 1998-09-09 | 2002-02-12 | Aerospatiale | Device for locating a rupture in a transparent panel with at least two panes and panel thus obtained |
US6641767B2 (en) | 2000-03-10 | 2003-11-04 | 3M Innovative Properties Company | Methods for replication, replicated articles, and replication tools |
US9428654B2 (en) | 2004-04-15 | 2016-08-30 | Avery Dennison Corporation | Dew resistant coatings |
US8354160B2 (en) | 2006-06-23 | 2013-01-15 | 3M Innovative Properties Company | Articles having durable hydrophobic surfaces |
US9896557B2 (en) | 2010-04-28 | 2018-02-20 | 3M Innovative Properties Company | Silicone-based material |
US10066109B2 (en) | 2010-04-28 | 2018-09-04 | 3M Innovative Properties Company | Articles including nanosilica-based primers for polymer coatings and methods |
US9285584B2 (en) | 2010-10-06 | 2016-03-15 | 3M Innovative Properties Company | Anti-reflective articles with nanosilica-based coatings and barrier layer |
Also Published As
Publication number | Publication date |
---|---|
KR19990087059A (en) | 1999-12-15 |
CA2244922A1 (en) | 1997-08-28 |
CN1211332A (en) | 1999-03-17 |
AU1700497A (en) | 1997-09-10 |
EP0882285A1 (en) | 1998-12-09 |
JP2000505211A (en) | 2000-04-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN100472245C (en) | Retroreflective sheeting with controlled CAP-Y | |
EP1659425B1 (en) | Retroreflective sheet and external illumination type illumination system | |
CA2222587C (en) | Wet retroreflective marking material | |
EP0747736B1 (en) | Retroreflecting sheet which emits light when irradiated with ultraviolet ray | |
US7048989B2 (en) | Retroreflective article comprising water-borne acrylic topcoats | |
MXPA97010351A (en) | Human retrorreflective marker material | |
CA2222565A1 (en) | High entrance angle retroreflective article with spherical refracting elements | |
US6703108B1 (en) | Wet retroreflective marking material | |
EP0882285A1 (en) | Dew-resistant retroreflective traffic sign having a textured glass surface | |
JP4113981B2 (en) | Bidirectional retroreflective sheet | |
MXPA98006620A (en) | Retrorreflexive traffic signal resistant to rocio, which has a texturized glass surface | |
JPH07218708A (en) | Night retroreflection sheet | |
GB2323711A (en) | Flexible magnetic articles | |
MXPA97010362A (en) | Retrorreflejante article of elevated inlet angle, with refracc spherical elements | |
Mohan et al. | Characteristics of retroreflective materials used in traffic control devices | |
MXPA97010371A (en) | A retrorreflejante article of angle of entradagrande and method of fabricac |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 97192323.X Country of ref document: CN |
|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG UZ VN AM AZ BY KG KZ MD RU TJ TM |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref document number: 2244922 Country of ref document: CA Ref document number: 2244922 Country of ref document: CA Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1997902948 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: PA/a/1998/006620 Country of ref document: MX |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1019980706445 Country of ref document: KR |
|
WWP | Wipo information: published in national office |
Ref document number: 1997902948 Country of ref document: EP |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
WWR | Wipo information: refused in national office |
Ref document number: 1997902948 Country of ref document: EP |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1997902948 Country of ref document: EP |
|
WWP | Wipo information: published in national office |
Ref document number: 1019980706445 Country of ref document: KR |
|
WWW | Wipo information: withdrawn in national office |
Ref document number: 1019980706445 Country of ref document: KR |