KR19990028420A - Retroreflective material - Google Patents

Abstract

The present invention relates to a retro-reflective road marking material (10) comprising a lens-exposed retroreflective sheet (12) on an upper surface, the sheet comprising a single layer of retroreflective elements, wherein the first portions of the single layer It is arranged with the profile 18 formed upwardly, and the second portions of the monolayer are arranged in a lower, substantially planar position 20.

Description

Retroreflective material

Road signs, such as the center line of the road and the outside lanes, are important for visually guiding motorists. Road marking materials are used as traffic control signs for many purposes, such as short lane lane stripes on roads, stop lines, pedestrian road signs at intersections, and long lane signs. A common form of road marking material is an adhesive-backed tape that is attached to the road surface at the desired location and length. The upper surface of the tape has the properties of selected color and usually retroreflective properties.

Currently, many flat road signs typically rely on exposed-lens optical systems, which are either titanium dioxide (TiO ₂ ) or lead chromate (PbCrO ₄ ) as retroreflector mechanisms. Permeable microspheres partially embedded in a binder layer containing reflective pigment particles such as In use, light from the headlamps of the vehicle enters the microspheres and is refracted to reach the reflective pigments. Some of the light is typically returned to the vehicle along the original entry path for the driver to see.

Low profile road signs currently available sometimes provide an effective retroreflective response only for a narrower range of entrance angles than desired. For example, a flat road sign that relies on microspheres partially embedded in a layer containing a diffusion pigment, as described above, is readily visible at distances of about 80 meters or less. At longer distances, the retroreflective luminous intensity decreases in part because of the relatively larger entrance angle of the incident light, and in part because of the inherently limited retroreflective luminous intensity.

U.S. Patent Nos. 4,388,359 to Ethen et al., 4,988,555, 4,988,541 and 5,227,221 to Hedblom include microspheres partially embedded in a binder layer containing pigment material and protruding from the binder layer. Disclosed is a road marking sheet having a protrusion. This structure provides improved retroreflective brightness at large entrance angles, but at high manufacturing costs.

In addition, a failure aspect of many road marking materials is that the adhesive binder with the road surface is weakened and lost, which removes a significant portion of the marking tape.

There is a need for a low profile, low profile retroreflective product that maintains effective retroreflective luminosity at high incidence angles, and is durable, even at high incidence angles even when the incidence angle is large. In addition, retroreflectivity exhibits an effective retroreflective response over a wide range of angles of entry for use on vertical surfaces such as guard rails, Jersey barriers, abutments of walls, and walls. Products are required.

The present invention relates to retroreflective marking material.

1 is a plan view of a portion of a road marking material in accordance with the present invention.

2 is a cross-sectional view of the material shown in FIG. 1.

3 is a cross-sectional view of a road marking material according to another embodiment of the present invention.

In accordance with the present invention, a novel material is provided which exhibits surprisingly effective retroreflective properties and which can be produced at a relatively low cost. The material according to the invention exhibits effective retroreflective performance at large entering angles (eg 85 ° or more) and is suitable for use on vertical and horizontal surfaces. In addition, the marking material according to the present invention is surprisingly excellent in adhesion to the road, which can be used for a long time.

Definitions of some terms used in the present application are described at the end of the present specification. Reference is now made in detail to certain embodiments of the invention used in retroreflective road marking materials. It should be understood that many aspects of this embodiment may relate to embodiments used as retroreflective labels on vertical surfaces.

In short, the retroreflective material according to the present invention comprises an upper layer comprising a transparent microsphere protruding from the layer and partially embedded in a binder layer containing a plurality of exposed lenticular retroreflective elements, such as pigment particles. top layer). The first portions of the top layer are arranged in a profile formed upwardly (ie, relatively perpendicular to the body of the layer), and the second portions of the top layer are arranged in a lower, often substantially planar position. Typically, the material according to the invention comprises such a plurality of first and second portions in a single continuous sheet.

The retroreflective labeling material according to the invention can be produced in a flexible form and in the desired color. In addition, the materials presented herein can be made highly adaptable to low profile and to adapt well to road surfaces. When made of suitable materials, they are resistant to damage by vehicles and are suitable for use on roads, even when exposed to water, salt, oil, ultraviolet radiation, abrasion by sand, high temperatures, and the like. The material can be made in a continuous process and can be made quite inexpensively. If the labeling material according to the invention is attached to a roadway to provide a traffic control signage, the delineation is better visible to the driver and thus increase the stability.

Retroreflective products according to the invention are particularly suitable when light is incident on, for example, road markings at large entrance angles of greater than 85 °. Retroreflective products according to the invention are also suitable for the case where incident light enters from different directions. Intersect lines and so-called horizontal markers are for example. Examples of horizontal signs typically include symbols and symbols placed on a parking lot road to indicate handicapped parking and include arrows and lane signs placed on the road at intersections.

In addition, retroreflective products according to the invention are used on vertical surfaces, especially guard rails, vertical surfaces observed at large incidences such as building walls along narrow paths, low barriers, bridge shifts, columns, traffic barrels, etc. Suitable for

The present invention is explained below with reference to the accompanying drawings. The accompanying drawings that are idealized are not to be to scale, and are intended to illustrate the invention, not to limit the invention.

Products according to the present invention typically comprise a retroreflective top layer sheet, a shape member, any backing material, and an adhesive layer. The shape member is used to provide a portion formed upwardly in the product. Upward herein is used in connection with the fact that the first portions are usually raised from the second portions, and in connection with the fact that the road sign is usually attached to a horizontal surface. It will also be understood that in the vertical mark it may mean that the first portions protrude beyond the second portions.

Labeling materials illustrating the invention are shown in FIGS. 1 and 2. The material 10 includes a top layer 12 having microspheres 16 and skid particles 17 protruding from the binder layer 14. The first portion 18 of the top layer 12 is arranged in an upwardly contoured profile and the second portion 20 of the top layer 12 is arranged in a lower, often substantially planar position. . The label material 10 also includes a backing composed of an optional conformation layer 22 and an adhesive layer 24 capable of securing the material to a desired substrate, such as a road (not shown). In the illustrated embodiment, the first portion 18 is raised above the second portion 20 by the shape member 19.

The various components of retroreflective sheeting are preferably held together under repeated impact and shear stresses by vehicles on the road passing over the sheet in all types of weather conditions and when used as road markings.

The top layer comprises microspheres protruding from the binder layer containing the pigment particles. The advantage of such a lens system is that it can be manufactured in various required colors, brightly shining or pure daytime colors. This is particularly useful in embodiments intended for use on concrete or relatively other bright road surfaces where bright colored markings are required to better identify and see better during the day. The color and retroreflective viewing conditions required during the day can be achieved by selecting suitable pigments and dyeing materials for the binder layer and by selecting colorless or colored microspheres.

Typically for road marking applications, the backing material of the product includes any adaptation layer and / or any scrim layer known in the art. Those skilled in the art will readily be able to select suitable adaptation layers and scrim materials.

The adhesive provides a mechanism for attaching the retroreflective product to a surface, such as a road. If desired, an adhesive layer or primer layer may be attached to the surface prior to laminating the retroreflective product. The selection of suitable adhesives, such as, for example, pressure sensitive adhesives, hot melt adhesives, active adhesives, etc., depends in part on the conditions of use, the environment of the substrate and the nature of the layer of the product to which the adhesive layer should adhere. Those skilled in the art will readily be able to select an appropriate adhesive layer.

Typically, the road marking material according to the invention can be wound in the form of a roll. In such cases, it may be desirable to use a release liner or to apply a release treatment such as silicon to the top surface of the label.

As noted above, the upper layer portion has a profile formed such that the first portions face upward relative to the second portions. The advantages of these upwardly formed portions having a vertical profile are as follows. (1) Light with a large entry angle is more effectively reflected back. (2) Rainwater is drained if it is present. (3) Increases the adhesion to the road when the tire repeatedly contacts the upwardly formed portions.

The desired profile, optionally formed upwardly, may be a single member, such as a single member, such as a mesh of connected fibers, or an array of separate members, such as, for example, an array of independent fibers or nodules. It is formed by a shape member. For example, meshes of point bonded nylon or polyester fibers are preferred, where the mesh is discontinuous with holes between the fibers. The aperture allows the peripheral elements such as, for example, the top layer and the adhesive layer, to be bonded directly to each other via the shape member. The shape member may be in any suitable form as long as it raises some portions of the retroreflective sheeting as described herein. The shape member should be flexible so that it can be easily adapted to the road.

As used herein, the shape member is typically a polymer. Examples of polymeric materials include polyolefinic copolymers, such as polyethylene acid copolymers consisting of ethylene methacrylic acid (EMAA), ethylene acrylic acid (EAA), ionically crosslinked EMAA or ionically crosslinked EAA, and poly There is urethane.

In some cases, the first portions may be in the form of separate protrusions. This can be achieved using a nodule array as a shape member. The nodule may be substantially free standing or connected by relatively thinner filaments. The latter embodiment is usually easier for handling purposes during shaping of the retroreflective labeling material.

In some embodiments, the first portions may be in the form of strips that do not substantially intersect or in the form of strips that intersect in the interconnected network. Each strip may be substantially straight, curved, placed in a nested array of curved shapes, or any other shape as desired. The shape and arrangement of the first parts form the shape of the second parts. Some examples of second part forms include rectangles, diamonds, hexagons, and the like. If the first portions intersect, the second portions can be separated from each other. If the first portions are detachable and not connected, the second portions are adjacent. If desired, these arrangements can be used in combination.

The other components of the product must be sufficiently adaptable to obtain the desired profile formed to face the top sheet. Preferably, the shape member will attach itself to the adaptation layer if it is present, which is believed to produce a more durable final product. In addition to providing the functionality disclosed herein, meshes provide improved mechanical properties to road marking materials in a manner similar to the scrims disclosed in US Pat. No. 4,146,645 to Eigenmann and US Pat. No. 4,299,874 to Johnson et al. It can be given.

In some embodiments, some portions of the upwardly formed portions may be higher than other portions of the first portions. For example, in the above-described rectangular embodiment, portions formed upwardly perpendicular to the travel direction may be raised higher than portions formed upwardly parallel to the travel direction. In this way, portions formed higher upwards provide effective retroreflective performance. Lower, upward-facing parts can drain if there is water.

Regardless of which form is to be formed, it is preferable to select the heights of the portions formed upwardly with the distance between these portions in mind. For example, the portions formed upwardly along the line of sight from the approaching vehicle should be kept far enough to minimize blurring. Preferably, the distance between the portions formed upwardly (ie, the width of the second portions) is 3 mm or more. Typically, the top of the first portions is raised to a height of at least 0.1 mm, preferably between 1 mm and 4 mm, above the second portions. Although the space between the upwardly formed portions can be closer together without significantly affecting the retroreflected light intensity, a larger number of shape members are required than are optimally required. Likewise, the space between the upwardly formed portions can be made larger but the brightness decreases in closer viewing. However, the luminous intensity at longer viewing is not affected. As used herein, "closer field of view" means that the distance between the vehicle and the material of the present invention is shorter. For example, a distance of about 30 m. By "distant clock" it is meant that the distance between the vehicle and the material of the invention is greater. For example, a distance of about 120 m. Those skilled in the art will be able to select and design patterns of appropriate shapes in accordance with the present invention.

The labeling material according to the invention can be easily produced by laminating the preformed top layer, the shape member, the adaptation layer, and the adhesive layer, if desired, simultaneously or separately in the desired order. Other components can be assembled and, if necessary, a top layer can be formed thereon.

An advantage of the present invention is that the binder layer material can be easily processed into a mesh or net used as a shape member and easily incorporated into the label material to selectively emboss the protrusions in the member and then have the projecting microspheres. It is possible to obtain the desired profile formed upwards more easily and at a lower cost than by applying or forming a.

In some instances, it is desirable to partially embed skid control particles, sometimes referred to as anti-skid particles, in the top layer to improve the traction of the passing vehicle. Anti-skid particles are well known in the art. Those skilled in the art will readily be able to select the appropriate embodiment.

Typically, the anti-skid particles can be randomly sprayed onto the top layer and the binder layer is in a softened state. It has been found that the anti-skid particles may be preferentially placed adjacent to the apex of the upwardly formed portions. For example, a web of retroreflective sheet with upwardly formed portions can be kiss-coated on top of the first portion with the binder composition, and a large amount of anti-entry when the binder composition remains dry. Skid particles are sprayed onto the web. The remainder of the retroreflective sheet is dried, so that the particles adhere only to the dry areas. Excess anti-skid particles are vibrated to separate from the web. The web is then sent to a series of ovens to dry, cure or harden the dry binder composition. As a result, the anti-skid particles are fixed on top of the upwardly formed portions to provide anti-skid resistance. This approach can result in some loss of retroreflective performance.

The material according to the invention can itself be wound in the form of a roll. The overhangs created by the upwardly formed profile are not substantially sufficient to prevent winding.

In a typical embodiment of a road sign used for lane markings, the material according to the present invention is about 7.5 cm to 30 cm (3 inches to 12 inches) wide and at least 30 cm (12 inches) long. Usually, road signs are much longer. Labeling materials according to the present invention are typically formed in sizes consistent with standard materials. In the United States, road marking tapes are typically about 4 inches, about 6 inches or about 8 inches wide. In Europe, road marking tapes are typically about 15 cm or 30 cm in width.

Terms

The following definitions are used herein.

The "reference axis" is a line perpendicular to the retroreflective product at the point where light enters.

An "entrance axis" (sometimes referred to as an "incidence axis") is an axis formed by a light source, such as an incident light path from a headlight of a vehicle to an entry point on a product.

The "entrance angle (sometimes referred to as" incidence angle "or β)" is the angle between the reference axis and the incident axis.

An "observation axis" is an axis formed by a path of retroreflected light from a point of entry on a product to an observation point, such as the eyes of a vehicle driver.

The "observation angle (often called α)" is the angle between the entry axis and the observation axis.

An "entrance plane" is a plane formed by a reference axis and an incident axis.

"Observation plane" is a plane formed by the observation axis and the incident axis.

Many variations and modifications of the invention will be apparent to those skilled in the art without departing from the scope of the invention.

Claims (19)

(1) an upper layer partially embedded in the front face of the binder layer containing the pigment particles and comprising a plurality of microspheres projecting from the front face, wherein the first portions of the upper layer are arranged in a profile formed to face upwards, The second layer of the upper layer is disposed in a lower, substantially planar position; (2) a shape member for forming the first and second portions, (3) a retroreflective labeling material comprising an adhesive layer The retroreflective labeling material of claim 1, wherein the material further comprises a conformation layer. The retroreflective labeling material according to claim 2, wherein the adaptation layer is disposed between the upper layer and the shape member. The retroreflective labeling material according to claim 2, wherein the adaptation layer is disposed between the shape member and the adhesive layer. The retroreflective labeling material of claim 1, wherein an upper portion of the first portions is raised at least 0.1 mm higher than the second portions. The retroreflective labeling material of claim 1, wherein the tops of the first portions are raised about 1 mm to 4 mm higher than the second portions. The retroreflective labeling material of claim 1, wherein the width of the second portions is at least 3 mm. The retroreflective labeling material of claim 1, wherein the first portions are in the form of separate protrusions. The retroreflective labeling material of claim 1, wherein the first portions are in the form of strips. 10. The retroreflective labeling material of claim 9, wherein the strips do not substantially intersect. 10. The retroreflective labeling material of claim 9, wherein the strips intersect in an interconnected network. 10. The retroreflective labeling material of claim 9, wherein the strips are substantially straight. 10. The retroreflective labeling material of claim 9, wherein the strips are arranged in a nested array of curved shapes. The retroreflective labeling material of claim 1, wherein the first portions are connected such that the second portions are any one of a rectangular, diamond, and hexagonal shape. The retroreflective labeling material of claim 1, wherein the retroreflective brightness of the material at an entry angle of 85 ° or greater is greater than the retroreflective brightness of the product without the first portions. The retroreflective labeling material of claim 1, further comprising anti-skid particles protruding from the front face. 2. The retroreflective labeling material of claim 1, wherein the label has a width of between about 7.5 cm and 15 cm and a length of at least 30 cm. Road surface marked with the material of claim 1. The method of claim 1, wherein the application is applied to a vertical placement surface selected from the group consisting of guard rails, Jersey barriers, building walls, fences, utility poles, traffic cones, and vehicle sides. Retroreflective labeling material characterized by the above-mentioned.