阅读说明：本技术 柔性逆反射片材 (Flexible retroreflective sheeting ) 是由 C-W·陈 于 2020-02-04 设计创作，主要内容包括：本文提供了一种柔性逆反射片材,其包括具有逆反射元件的压花层、与逆反射元件接触的背衬层和/或金属化层,以及夹在两个粘合剂层之间的中间层。具有所述结构的所述层的拉伸性质和颜色性质使得所述片材特别可用作用于经受压裂或弯曲的制品例如交通安全装置的标签。还提供了包括所提供的片材的方法和制品。(Provided herein is a flexible retroreflective sheeting that includes an embossed layer having retroreflective elements, a backing layer and/or a metallized layer in contact with the retroreflective elements, and an intermediate layer sandwiched between two adhesive layers. The tensile and color properties of the layers having the structure make the sheet particularly useful as a label for articles subject to fracturing or bending, such as traffic safety devices. Methods and articles comprising the provided sheet are also provided.)

1. A flexible retroreflective sheeting comprising:

an embossing layer having a front surface and an opposing back surface, the opposing back surface comprising a plurality of retroreflective elements;

a flexible backing layer in contact with the rear surface of the embossing layer;

a first adhesive layer connected to the flexible backing layer opposite the embossed layer;

a middle layer having an opacity greater than 40% and connected to the first adhesive layer opposite the flexible backing layer; and

a second adhesive layer connected to the intermediate layer opposite the first adhesive layer.

2. The flexible retroreflective sheet of claim 1, wherein the embossed layer has an embossed color and the intermediate layer has an intermediate layer color having a CIEDE2000 color difference from the embossed color of less than 20.

3. The flexible retroreflective sheeting of claim 1, wherein the embossed layer is transparent, wherein the flexible backing layer has a backing color and the intermediate layer has an intermediate layer color having a CIEDE2000 color difference from the embossed color of less than 20.

4. The flexible retroreflective sheeting of any of claims 1-3, wherein the intermediate layer comprises a colored film.

5. The flexible retroreflective sheeting of any of claims 1-4, having a tensile strain in the range of 30% to 200%.

6. The flexible retroreflective sheeting of any of claims 1-5, having a breaking force in the range of 20lbf to 60 lbf.

7. The flexible retroreflective sheet of any of claims 1-6 having a Young's modulus ranging from 45ksi to 275 ksi.

8. The flexible retroreflective sheeting of any of claims 1-7, wherein the intermediate layer has a thickness ranging from 0.2 mils to 4 mils.

9. The flexible retroreflective sheeting of any of claims 1-8, wherein the embossed layer has a thickness ranging from 0.5 mils to 10 mils.

10. The flexible retroreflective sheeting of any of claims 1-9, wherein the ratio of the embossed layer thickness to the intermediate layer thickness ranges from 0.1 to 20.

11. The flexible retroreflective sheeting of any of claims 1-10, wherein the intermediate layer comprises one or more polymers selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefin, and polyurethane.

12. The flexible retroreflective sheeting of any of claims 1-11, wherein the flexible backing layer comprises one or more polymers selected from the group consisting of polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefin, and polyurethane.

13. The flexible retroreflective sheeting of any of claims 1-12, wherein the embossed layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, and polyurethanes.

14. The flexible retroreflective sheeting of any of claims 1-13, wherein the flexible backing layer is directly attached to a portion of the rear surface of the embossing layer, and wherein the flexible backing layer and the retroreflective elements define a plurality of air gaps.

15. The flexible retroreflective sheeting of any of claims 1-14, wherein the first adhesive layer and the second adhesive layer each independently comprise a pressure sensitive adhesive.

16. The flexible retroreflective sheeting of any of claims 1-15, further comprising:

a flexible facing attached to the front surface of the embossing layer.

17. The flexible retroreflective sheeting of claim 16, wherein the flexible face layer has a thickness ranging from 1 mil to 35 mils.

18. The flexible retroreflective sheeting of claims 16 or 17, wherein the ratio of the thickness of the flexible face layer to the thickness of the embossing layer is in the range of 0.1 to 70.

19. The flexible retroreflective sheeting of any of claims 16-18, wherein a ratio of the thickness of the flexible face layer to the thickness of the intermediate layer ranges from 0.2 to 175.

20. The flexible retroreflective sheeting of any of claims 16-19, wherein the flexible face layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, polyolefins, and polyurethanes.

21. The flexible retroreflective sheeting of any of claims 1-20, further comprising:

a release liner adhered to the second adhesive layer opposite the intermediate layer.

22. The flexible retroreflective sheeting of any of claims 1-21, wherein the flexible backing layer has a backing color, and wherein the intermediate layer has an opacity of greater than 58% and an intermediate layer color having a CIEDE2000 color difference from the backing color of less than 10.

23. The flexible retroreflective sheeting of any of claims 1-22, wherein the intermediate layer has an opacity of greater than 58%, and wherein the flexible retroreflective sheeting has a tensile strength in a range of 30% to 150%.

24. The flexible retroreflective sheeting of any of claims 1-23, wherein the flexible backing layer has a backing color, wherein the interlayer has an interlayer color having a CIEDE2000 color difference from the backing color of less than 10, and wherein the flexible retroreflective sheeting has a tensile strength ranging from 30% to 150%.

25. A method for producing a flexible retroreflective sheeting, the method comprising:

thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer;

attaching a flexible backing layer to a rear surface of the embossing layer;

coating a first side of an intermediate layer with a first adhesive layer and an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape; and

laminating the transfer tape to the flexible backing layer opposite the embossing layer.

26. The method of claim 25, wherein the connecting comprises sealing the flexible backing layer to a portion of the rear surface of the embossed layer such that a plurality of air gaps are defined by the flexible backing layer and the retroreflective elements.

27. The method according to claim 25 or 26, wherein the thermal embossing further attaches a flexible facing layer to a front surface of the embossed layer opposite a rear surface of the embossed layer.

28. The method of any one of claims 25-27, further comprising:

attaching the backing layer to the second adhesive layer opposite the intermediate layer.

29. A flexible retroreflective sheeting comprising:

an embossing layer having a front surface and an opposing back surface, the opposing back surface comprising a plurality of retroreflective elements; wherein the embossed layer has an embossed color;

a metallized layer directly on a rear surface of the embossed layer;

a first adhesive layer connected to the metallized layer opposite the embossed layer;

an interlayer connected to the first adhesive layer opposite the metallized layer, wherein the interlayer has an opacity of greater than 40% and an interlayer color having a CIEDE2000 color difference from the embossed color of less than 20; and

a second adhesive layer connected to the intermediate layer opposite the first adhesive layer.

30. The flexible retroreflective sheeting of claim 29, wherein the intermediate layer comprises a cavitated film.

31. The flexible retroreflective sheeting of claims 29 or 30, having a tensile strain ranging from 30% to 200%.

32. The flexible retroreflective sheeting of any of claims 29-31, having a breaking force ranging from 20lbf to 60 lbf.

33. The flexible retroreflective sheet of any of claims 29-32 having a young's modulus ranging from 45ksi to 275 ksi.

34. The flexible retroreflective sheeting of any of claims 29-33, wherein the intermediate layer has a thickness ranging from 0.2 mils to 4 mils.

35. The flexible retroreflective sheeting of any of claims 29-34, wherein the embossed layer has a thickness ranging from 0.5 mils to 10 mils.

36. The flexible retroreflective sheeting of any of claims 29-35, wherein the ratio of the thickness of the embossed layer to the thickness of the intermediate layer ranges from 0.1 to 20.

37. The flexible retroreflective sheeting of any of claims 29-36, wherein the intermediate layer comprises one or more polymers selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefin, and polyurethane.

38. The flexible retroreflective sheeting of any of claims 29-37, wherein the embossed layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, and polyurethanes.

39. The flexible retroreflective sheeting of any of claims 29-38, wherein the retroreflective elements are metallized.

40. The flexible retroreflective sheeting of any of claims 29-39, wherein the first adhesive layer and the second adhesive layer each independently comprise a pressure sensitive adhesive.

41. The flexible retroreflective sheeting of any of claims 29-40, further comprising:

a flexible facing attached to a front surface of the embossed layer.

42. The flexible retroreflective sheeting of claim 41, wherein the flexible face layer has a thickness ranging from 1 mil to 35 mils.

43. The flexible retroreflective sheeting of claims 41 or 42, wherein the ratio of the thickness of the flexible face layer to the thickness of the embossing layer is in the range of 0.1 to 70.

44. The flexible retroreflective sheeting of any of claims 41-43, wherein the ratio of the thickness of the flexible face layer to the thickness of the intermediate layer ranges from 0.25 to 175.

45. The flexible retroreflective sheeting of any of claims 41-44, wherein the flexible facing layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, polyolefins, and polyurethanes.

46. The flexible retroreflective sheeting of any of claims 29-45, further comprising:

a release liner adhered to the second adhesive layer opposite the intermediate layer.

47. The flexible retroreflective sheeting of any of claims 29-46, wherein the interlayer has an opacity of greater than 58% and an interlayer color having a CIEDE2000 color difference from the embossed color of less than 10.

48. The flexible retroreflective sheeting of any of claims 29-47, wherein the intermediate layer has an opacity of greater than 58%, and wherein the flexible retroreflective sheeting has a tensile strength in a range of 30% to 150%.

49. A method for producing a flexible retroreflective sheeting, the method comprising:

thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer;

attaching a metallization layer directly to a back surface of the embossing layer;

coating a first side of an intermediate layer with a first adhesive layer and an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape; and

laminating the transfer tape to the metallized layer opposite the embossed layer.

50. The method according to claim 49, wherein the thermal embossing further attaches a flexible facing layer to a front surface of the embossed layer opposite a back surface of the embossed layer.

51. The method of claim 49 or 50, further comprising:

a release liner is attached to the second adhesive layer opposite the intermediate layer.

52. A method of applying a flexible retroreflective sheeting to a surface, the method comprising:

providing a surface having an exterior face;

providing a flexible retroreflective sheeting of any of claims 1-24 and 29-48; and

bonding the second layer of the flexible retroreflective sheeting to the outer face of the surface.

53. The method of claim 52, wherein the surface comprises one or more polymers selected from the group consisting of polyvinyl chloride, linear low density polyethylene, high density polyethylene, and polycarbonate.

54. An article of manufacture, comprising:

a surface having an exterior face; and

the flexible retroreflective sheeting of any of claims 1-24 and 29-48 adhered to the outer face of the surface.

55. The article of claim 54, wherein the surface comprises one or more polymers selected from the group consisting of polyvinyl chloride, linear low density polyethylene, high density polyethylene, and polycarbonate.

Technical Field

The present invention relates generally to flexible retroreflective sheeting particularly useful for traffic safety device labels.

Background

Traffic cones (towers) are cone-shaped markers that are often placed on roads or sidewalks to temporarily redirect traffic in a safe manner. For example, marker cones are often used to create separate or merged lanes during road construction projects or automobile accidents. In the united states, the Federal Highway Administration (Federal Highway Administration) handbook of unified Traffic Control Devices (MUTCD) requires that cones be fitted with reflective white bands to increase night visibility. A reflective ring, such as a white strip made of white reflective plastic, may be snugly slipped over the top of the cone and permanently or semi-permanently affixed to the traffic cone with tape or adhesive. Similar reflective strips, tapes or labels are also commonly attached to other traffic safety devices, such as traffic barrels (traffic barrels) and obstacles, to increase their visibility.

Since traffic cones are typically located on and near roads, they are very susceptible to impacts from, for example, vehicle and pedestrian collisions, causing the cone surface to crack or buckle. When a traffic cone is deformed in this manner, a label (e.g., a reflective ring) attached to the cone may experience stresses that may damage the integrity of the label. Such damage can cause cracks in the label structure, reveal the cone surface beneath the cracked label, and disrupt the consistency of the appearance of the label. The visual effect of the crack is particularly pronounced due to the significant contrast between the typical fluorescent orange color of traffic cones and other road safety devices and the typical white color of reflective labels. In view of these undesirable effects, there is a need for improved flexible adhesive retroreflective sheeting.

Disclosure of Invention

In one embodiment, the present disclosure is directed to a flexible retroreflective sheeting that includes an embossed layer, a flexible backing layer, a first adhesive layer, an intermediate layer, and a second adhesive layer. Preferably, the sheet has a tensile strain in the range of 30% to 200%. The embossed layer has a back surface comprising a plurality of retroreflective elements. The flexible backing layer is in contact with the rear surface of the embossing layer. The first adhesive layer is connected to the flexible backing layer opposite the embossed layer. The intermediate layer has an opacity of greater than 40% and is connected to the first adhesive layer opposite the flexible backing layer. Preferably, the intermediate layer has a CIEDE2000 color difference from the embossed layer color of less than 20. Preferably, the intermediate layer comprises a cavitated film or a pigmented film. The second adhesive layer is connected to the intermediate layer opposite the first adhesive layer.

In another embodiment, the present disclosure is directed to a method for producing a flexible retroreflective sheeting having a flexible backing layer. The method includes thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer. The method further includes attaching a flexible backing layer to the rear surface of the embossing layer. The method further includes coating a first side of the intermediate layer with a first adhesive layer and coating an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape. The method further includes laminating the transfer tape to the flexible backing layer opposite the embossing layer.

In another embodiment, the present disclosure is directed to a flexible retroreflective sheeting that includes an embossed layer, a metallized layer, a first adhesive layer, an intermediate layer, and a second adhesive layer. Preferably, the sheet has a tensile strain in the range of 30% to 200%. The rear surface of the embossing layer includes a plurality of retroreflective elements. The metallized layer is located directly on the rear surface of the embossed layer. The first adhesive layer is connected to the metallized layer opposite the embossed layer. The intermediate layer is connected to the first adhesive layer opposite the metallized layer, has an opacity of greater than 40%, and has a CIEDE2000 color difference from the embossed layer color of less than 20. Preferably, the intermediate layer comprises a cavitated film or a pigmented film. The second adhesive layer is connected to the intermediate layer opposite the first adhesive layer.

In another embodiment, the present disclosure is directed to a method for producing a flexible retroreflective sheeting having a metallized layer. The method includes thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer. The method further includes attaching a metallization layer directly to the embossed layer back surface. The method further includes coating a first side of the intermediate layer with a first adhesive layer and coating an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape. The method further includes laminating the transfer tape to the metallized layer opposite the embossed layer.

In another embodiment, the present disclosure is directed to a method of applying a flexible retroreflective sheeting to a surface. The method includes providing a surface having an exterior face. The method further includes providing a flexible retroreflective sheeting as disclosed herein. The method further includes bonding the second layer of the flexible retroreflective sheeting to the outer face of the surface.

In another embodiment, the present disclosure is directed to an article marked with a flexible retroreflective sheeting as described herein. The article includes a surface having an exterior face, and the flexible retroreflective sheeting bonded to the exterior face of the surface.

Drawings

The present disclosure makes reference to the accompanying drawings, wherein like reference numerals refer to like parts.

Fig. 1 illustrates a flexible retroreflective sheeting structure according to an embodiment.

Detailed Description

The present invention relates generally to retroreflective sheeting that, when used, for example, as retroreflective labels for articles subject to fracturing and bending, provides advantageous improvements in label integrity and hiding power. For example, for a sheet material (e.g., a cone ring) applied to a traffic safety device (e.g., a traffic cone), if the device is handled, stepped on, or driven over roughly, it is beneficial that the sheet material be strong and flexible enough so as not to undergo delamination or cracking. It is beneficial for retroreflective sheeting to continue to conceal the underlying marking surface even in the event that the label develops cracks in one or more of the component layers. The ability of the sheeting to prevent the marking surface from being visible can advantageously improve the consistency of the appearance of the label.

However, conventional retroreflective sheeting, labels, or tape have difficulty meeting these requirements. One reason for this is that if the sheet is to form a tight bond to the traffic safety device, the sheet intended to be applied to the traffic safety device must be able to conform to the highly curved surfaces of the cone, cylinder and obstacle. However, the properties of such sheets that promote such conformability are contrary to the properties that promote rigidity and toughness, such that conventional sheets are susceptible to cracking under force. Retroreflective sheeting can include, inter alia, structural features known to be particularly likely to fracture upon impact. For example, air-backed retroreflective sheeting includes layers that do not completely contact each other because these partially connected layers form air gaps that impart retroreflectivity to the sheeting. These locations of incomplete contact between layers may be weak points that may break under stress.

The inventors have now found that particular combinations of layers having the compositions and geometries disclosed herein surprisingly provide improved performance characteristics for retroreflective sheeting. In particular, it has been found that the use of certain intermediate layers, along with structures having certain adhesive layers and embossed layers, can result in multilayer retroreflective sheeting having advantageous tensile properties. Advantageously, these improved properties may impart greater crack resistance to the provided sheet. In addition, the present disclosure also provides certain combinations of colors between different layers of the sheet. Other advantages are thus realized in that the durable and opaque inner layer (e.g., middle layer) of the sheet can have a color that is significantly similar to the upper layer, allowing the middle layer to continue to hide the underlying surface and visually blend with the upper layer (e.g., embossed layer) when the upper layer has developed cracks or fissures.

Retroreflective sheeting

In one aspect, a flexible retroreflective sheeting is disclosed. The sheeting comprises a multilayer structure having an embossed layer with retroreflective elements on its back surface, a flexible backing layer and/or a metallized layer at least partially in contact with the retroreflective elements, and a transfer tape connected to the backing layer or the metallized layer. The transfer tape includes an at least partially opaque intermediate layer sandwiched between a pair of adhesive layers. The first adhesive layer connects the transfer tape to the backing layer or metallized layer, and the second adhesive layer can be the exterior face of the sheet to be adhered to the article.

Fig. 1 illustrates an exemplary embodiment of the provided sheet. Retroreflective sheeting structure 100 is shown. The sheeting includes an embossed layer 101, the embossed layer 101 having a pattern of retroreflective elements 102 embossed into the rear surface of the embossed layer. In some embodiments, and as shown in fig. 1, the retroreflective elements are prisms or cube corner retro-reflectors. The front surface of the embossed layer is attached to a facing layer 103, and the facing layer 103 may provide a durable and/or printable exterior to the sheet, for example. A flexible backing layer 104 is in contact with a portion of the rear surface of the embossing layer such that the backing layer and retroreflective elements together define a plurality of air gaps 105. The first adhesive layer 106 is attached to the flexible backing layer and the intermediate layer 107 is disposed between the first adhesive layer and the second adhesive layer 108. The sheet also includes a release liner 109 attached to the second adhesive layer.

The composition and structure of the sheet may be configured to provide a tensile strain to the film sufficient to allow the sheet to deform with minimal or no fracture (e.g., cracking) when subjected to a tensile force. In this way, when the sheet is applied to an object such as a traffic cone that is susceptible to being impacted or fractured by vehicular or pedestrian traffic, the likelihood that the integrity and consistency of the sheet is affected may be reduced.

The tensile strain of the sheet may for example be in the following ranges: 30% to 200%, e.g., 30% to 132%, 47% to 149%, 64% to 166%, 81% to 183%, or 98% to 200%. The tensile strain of the sheet may be in the following ranges: 30% to 150%, e.g., 30% to 102%, 42% to 114%, 54% to 126%, 66% to 138%, or 78% to 150%. With respect to the upper limit, the sheet tensile strain may be less than 200%, e.g., less than 183%, less than 166%, less than 149%, less than 138%, less than 126%, less than 114%, less than 102%, less than 90%, less than 78%, less than 66%, less than 54%, or less than 42%. With respect to the lower limit, the sheet tensile strain may be greater than 30%, e.g., greater than 42%, greater than 54%, greater than 66%, greater than 78%, greater than 90%, greater than 102%, greater than 114%, greater than 126%, greater than 138%, greater than 149%, greater than 166%, or greater than 183%. Higher tensile strains, e.g., greater than 200%, and lower tensile strains, e.g., less than 30%, are also contemplated. Tensile strain may be measured using, for example, the standard protocol ASTM D828-16e1 (2016).

Similarly, the composition and structure of the sheet may be configured to provide a breaking force to the film that is sufficient to prevent the sheet from breaking, e.g., cracking, when subjected to a force or load below a high threshold. The breaking force of the sheet may for example be in the following ranges: 20lbf to 60lbf, for example, 20lbf to 44lbf, 24lbf to 48lbf, 28lbf to 52lbf, 32lbf to 56lbf, or 36lbf to 60 lbf. With respect to the upper limit, the sheet can have a break force of less than 60lbf, e.g., less than 56lbf, less than 52lbf, less than 48lbf, less than 44lbf, less than 40lbf, less than 36lbf, less than 32lbf, less than 28lbf, or less than 24 lbf. With respect to the lower limit, the sheet can have a break force of greater than 20lbf, e.g., greater than 24lbf, greater than 28lbf, greater than 32lbf, greater than 36lbf, greater than 40lbf, greater than 44lbf, greater than 48lbf, greater than 52lbf, or greater than 56 lbf. Greater breaking forces, e.g., greater than 60lbf, and lesser breaking forces, e.g., less than 20lbf, are also contemplated. The breaking force can be measured using, for example, the standard protocol ASTM D828-16e1 (2016).

The sheet may also be configured to provide the film with a sufficient Young's modulus (Young's modulus) to allow the sheet to withstand stretching or compression when subjected to a longitudinal force. The young's modulus of the sheet may for example be in the following range: 45ksi to 275ksi, e.g., 45ksi to 183ksi, 68ksi to 206ksi, 91ksi to 229ksi, 114ksi to 252ksi, or 137ksi to 275 ksi. With respect to the upper limit, the sheet may have a Young's modulus of less than 275ksi, e.g., less than 252ksi, less than 229ksi, less than 206ksi, less than 183ksi, less than 160ksi, less than 137ksi, less than 114ksi, less than 91ksi, or less than 68 ksi. With respect to the lower limit, the sheet may have a Young's modulus of greater than 45ksi, e.g., greater than 68ksi, greater than 91ksi, greater than 114ksi, greater than 137ksi, greater than 160ksi, greater than 183ksi, greater than 206ksi, greater than 229ksi, or greater than 252 ksi. Greater Young's moduli, e.g., greater than 275ksi, and lesser Young's moduli, e.g., less than 45ksi, are also contemplated. Young's modulus can be measured using, for example, the standard protocol ASTM D828-16e1 (2016).

Embossed layer

The embossed layer may be colored or colorless. The embossed layer is typically substantially transparent, but may in some aspects be at least partially opaque. The material of the embossing layer may be selected from a wide variety of polymers including, but not limited to, polycarbonate, polyester, polystyrene, polyarylate, styrene-acrylonitrile copolymers, urethane, acrylates, cellulose esters, ethylenically unsaturated nitrites, hard epoxy acrylates, acrylics, and the like, with acrylic, polycarbonate, and polyurethane polymers being preferred. In some embodiments, the embossed layer comprises an acrylic. In some embodiments, the embossing layer comprises polycarbonate. In some embodiments, the embossed layer comprises both acrylic and polycarbonate.

The embossed layer can have a thickness in a range of, for example, 0.5 mil to 10 mil (e.g., 0.5 mil to 3 mil, 0.7 mil to 4.1 mil, 0.9 mil to 5.5 mil, 1.2 mil to 7.4 mil, or 1.7 mil to 10 mil). With respect to the upper limit, the thickness of the embossed layer can be less than 10 mils, e.g., less than 7.4 mils, less than 5.5 mils, less than 4.1 mils, less than 3 mils, less than 2.2 mils, less than 1.7 mils, less than 1.2 mils, less than 0.9 mils, or less than 0.7 mils. With respect to the lower limit, the thickness of the embossed layer may be greater than 0.5 mil, such as, for example, greater than 0.7 mil, greater than 0.9 mil, greater than 1.2 mil, greater than 1.7 mil, greater than 2.2 mil, greater than 3 mil, greater than 4.1 mil, greater than 5.5 mil, or greater than 7.4 mil. Greater thicknesses, such as greater than 10 mils, and lesser thicknesses, such as less than 0.5 mils, are also contemplated.

In certain aspects, the retroreflective elements of the embossed layer comprise an arrangement or pattern of prism elements embossed into or disposed into the rear surface of the embossed layer. The prism elements may be any three-dimensional shape of prism elements. In some embodiments, the prism elements comprise prism cube corners. In certain aspects, the retroreflective elements comprise an arrangement or pattern of beads (e.g., glass or ceramic microspheres).

Backing layer

In some embodiments, a flexible backing layer is attached directly to a portion of the rear surface of the embossing layer, and the flexible backing layer and retroreflective elements define a plurality of air gaps. These air gaps can contribute, at least in part, to the retroreflective properties of the sheeting by providing a material (e.g., air) having a refractive index that is substantially different from the refractive index of the embossed layer and in intimate contact with the retroreflective elements.

The backing layer may be colored or colorless. The backing layer may be substantially transparent or may be substantially opaque. The material and structure of the backing layer may be selected for properties such as flexibility. The flexible backing layer may comprise, for example, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefin, polyurethane, or combinations thereof. In some cases, the flexible backing layer comprises polycarbonate or polyvinyl chloride.

In some embodiments, the sheet includes a metallized layer instead of or in addition to a backing layer. The metallization layer or metal coating may comprise a metal such as aluminum, silver or chromium. The metallized layer can be disposed directly onto the retroreflective elements. In certain aspects in which the sheeting comprises a metallized layer, the sheeting further comprises a backing layer that at least partially serves as a protective layer for the metal coating that protects the retroreflective elements.

Intermediate layer

The composition and structure of the intermediate layer can be selected to provide a sufficiently high opacity to the layer to block the view of the materials and surfaces underlying the intermediate layer. In this manner, the intermediate layer may help prevent the marking surface underneath the sheeting from being visible, and may contribute to a consistent appearance of the sheeting. As used herein, the term "opacity" refers to the ratio of the reflectance of a film on a black substrate to the reflectance of the same film on a white substrate. The opacity of the intermediate layer may be, for example, in the following ranges: 40% to 100%, e.g., 40% to 76%, 46% to 82%, 52% to 88%, 58% to 94%, or 64% to 100%. As an upper limit, the opacity of the intermediate layer may be less than 100%, e.g., less than 94%, less than 88%, less than 82%, less than 76%, less than 70%, less than 64%, less than 58%, less than 52%, or less than 46%. With respect to the lower limit, the opacity of the intermediate layer may be greater than 40%, for example, greater than 46%, greater than 52%, greater than 58%, greater than 64%, greater than 70%, greater than 76%, greater than 82%, greater than 88%, or greater than 94%. Lower opacity is also contemplated, e.g., less than 40%. Opacity can be measured using, for example, the standard protocol ASTM D1003-13 (2013). The present inventors have found that the use of these durable and sufficiently opaque interlayers surprisingly provides the combined and synergistic benefits of crack resistance and the ability to conceal cracks that may occur, as disclosed herein.

The composition and structure of the intermediate layer may also be selected to provide the layer with a color that closely matches the color of the overlying layer of the sheet. This may allow the intermediate layer to contribute to a consistent appearance of the sheet in the event that the intermediate layer becomes visible through the cover layer, for example if the cover layer cracks. In certain aspects, the intermediate layer has a white color. In some embodiments, the intermediate layer is colored. In certain aspects, the intermediate layer has a yellow color, such as a fluorescent yellow color. In certain aspects, the intermediate layer has a green color, such as a fluorescent green color. In certain aspects, the intermediate layer has a yellow-green color. The difference between the color of the intermediate layer and the color of the cover layer may be represented by a formula, such as CIEDE2000(2001) developed by the International Commission on Illumination (CIE). These equations define a distance metric (Δ E) having a value of 0 to 100^*) Wherein a value less than 1 indicates a color difference that is visually imperceptible to a human, and a value of 100 indicates a difference between colors that are completely opposite to each other.

In some embodiments, the middle layer has a color similar to the embossed layer of the sheet. The CIEDE2000 color difference between the middle layer color and the embossed layer color may be in the following ranges, for example: 0 to 20, e.g., 0 to 12, 2 to 14, 4 to 16, 6 to 18, or 8 to 20. As an upper limit, the difference between the interlayer color and the embossed color can be less than 20, e.g., less than 18, less than 16, less than 14, less than 12, less than 10, less than 8, less than 6, less than 4, or less than 2. With respect to the lower limit, the difference between the interlayer color and the embossed color may be greater than 0, e.g., greater than 2, greater than 4, greater than 6, greater than 8, greater than 10, greater than 12, greater than 14, greater than 16, or greater than 18. Greater chromatic aberration is also contemplated, e.g., greater than 20.

In some embodiments, the intermediate layer has a color similar to the backing layer of the sheet. The CIEDE2000 color difference between the middle layer color and the backing layer color may be in the following ranges, for example: 0 to 20, e.g., 0 to 12, 2 to 14, 4 to 16, 6 to 18, or 8 to 20. As an upper limit, the difference between the color of the middle layer and the color of the backing layer can be less than 20, e.g., less than 18, less than 16, less than 14, less than 12, less than 10, less than 8, less than 6, less than 4, or less than 2. With respect to the lower limit, the difference between the color of the middle layer and the color of the backing layer may be greater than 0, e.g., greater than 2, greater than 4, greater than 6, greater than 8, greater than 10, greater than 12, greater than 14, greater than 16, or greater than 18. Greater chromatic aberration is also contemplated, e.g., greater than 20.

In some embodiments, the intermediate layer is cavitated, e.g., the intermediate layer comprises a cavitated film. The cavitating agent of the cavitated film may comprise one or more inorganic and/or organic particulate solids. The cavitating agent may include an organic solid, such as calcium carbonate. In some embodiments, the cavitating agent includes one or more polymers, such as a polyester or polycarbonate. In certain aspects, the cavitating agent comprises a polar polymer. The cavitating agent may include, for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene 2, 6-naphthalate (PEN), Polycarbonate (PC), or combinations thereof. The cavitating agent may be added to the membrane in the form of a particulate solid concentrate or additive concentrate in a thermoplastic polymer carrier (such as a propylene polymer blend) in an amount of 10 wt% to 90 wt%.

In addition to color properties, the structural integrity of the interlayer should also be considered in selecting interlayer materials and structures. The intermediate layer may comprise, for example, polyethylene terephthalate, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefin, polyurethane, or combinations thereof. In some embodiments, the intermediate layer comprises polyethylene terephthalate. In some embodiments, the intermediate layer comprises a colored polyethylene terephthalate.

The middle layer may have a thickness in a range of, for example, 0.2 mil to 4 mil (e.g., 0.2 mil to 1.2 mil, 0.3 mil to 1.6 mil, 0.4 mil to 2.2 mil, 0.5 mil to 3 mil, or 0.7 mil to 4 mil). With respect to the upper limit, the thickness of the middle layer may be less than 4 mils, e.g., less than 3 mils, less than 2.2 mils, less than 1.6 mils, less than 1.2 mils, less than 0.9 mils, less than 0.7 mils, less than 0.5 mils, less than 0.4 mils, or less than 0.3 mils. With respect to the lower limit, the thickness of the middle layer may be greater than 0.2 mils, e.g., greater than 0.3 mils, greater than 0.4 mils, greater than 0.5 mils, greater than 0.7 mils, greater than 0.9 mils, greater than 1.2 mils, greater than 1.6 mils, greater than 2.2 mils, or greater than 3 mils. Greater thicknesses, such as greater than 4 mils, and lesser thicknesses, such as less than 0.2 mils, are also contemplated.

The ratio of the embossing layer thickness to the intermediate layer thickness may for example be in the following ranges: 0.1 to 20, e.g., 0.1 to 2.4, 0.2 to 4.1, 0.3 to 6.9, 0.5 to 11.8, or 0.8 to 20. With respect to the upper limit, the thickness ratio of the embossed layer to the intermediate layer may be less than 20, for example, less than 11.8, less than 6.9, less than 4.1, less than 2.4, less than 1.4, less than 0.8, less than 0.5, less than 0.3, or less than 0.2. With respect to the lower limit, the thickness ratio of the embossed layer to the intermediate layer may be greater than 0.1, e.g., greater than 0.2, greater than 0.3, greater than 0.5, greater than 0.8, greater than 1.4, greater than 2.4, greater than 4.1, greater than 6.9, or greater than 11.8. Higher ratios, e.g., greater than 20, and lower ratios, e.g., less than 0.1, are also contemplated. The inventors have found that maintaining the ratio of embossed layer thickness to interlayer thickness within these ranges and/or limits surprisingly provides an improvement in the ability to hide cracks that may occur. It is assumed that the intermediate layer must have a sufficient thickness (relative to the embossed layer) to conceal the cracks. Without sufficient thickness, cracks will occur in the intermediate layer or will not be hidden due to the lack of opaque delamination.

First adhesive layer and second adhesive layer

The composition of the first adhesive layer may be selected to provide a strong bond to the backing layer, the metallized layer, or the material of another layer to which the first adhesive layer will be attached. The composition of the second adhesive layer may be selected to provide strong adhesion to the surface material of the article (e.g., the transportation device to which the second adhesive layer will be attached). The composition of the first adhesive layer and the second adhesive layer may also be selected to provide strong adhesion to the interlayer material. In certain aspects, the second adhesive layer is not present in the sheet structure. In these cases, the intermediate layer may be an outer layer of the sheet, and the sheet may be configured to wrap tightly over the surface of the object (e.g., traffic cone) such that an adhesive bond between the sheet and the object is not required.

The first adhesive layer and the second adhesive layer may each independently comprise a pressure sensitive adhesive. In certain aspects, one or both of the first adhesive layer and the second adhesive layer comprises an emulsion. In certain aspects, one or both of the first adhesive layer and the second adhesive layer comprises a hot melt adhesive. In some embodiments, the adhesive may be formed from an acrylic-based polymer. The adhesive may also be rubber-based, or a radiation curable mixture of monomers with initiators and other ingredients. Tackifiers, plasticizers, and other additives may be included in the adhesive to impart desired properties. Additives may include cutting agents such as waxes and surfactants, light stabilizers, heat stabilizers, ultraviolet light absorbers, heat absorbers, and combinations thereof.

Surface layer

In certain aspects, the sheeting comprises a single facing. The sheet may also include two facing layers or more than two layers, arranged in a stacked configuration with different facing layers having different properties and imparting different benefits to the multilayer sheet. Each side of the sheet may be independently colored or may be colorless. Each side of the sheet may independently be substantially transparent or may be substantially opaque. The material and structure of the layers may be selected for properties such as flexibility and printability. The facing layer may comprise, for example, polyvinyl chloride, acrylics, polycarbonate, polyolefin, polyurethane, or combinations thereof. In some embodiments, the facing layer comprises polyvinyl chloride.

The facing layer may have a thickness in a range of, for example, 1 mil to 35 mils (e.g., 1 mil to 8.4 mils, 1.4 mil to 12 mils, 2 mils to 17.2 mils, 2.9 mils to 24.5 mils, or 4.1 mils to 35 mils). With respect to the upper limit, the thickness of the facing layer may be less than 35 mils, e.g., less than 24.5 mils, less than 17.2 mils, less than 12 mils, less than 8.4 mils, less than 5.9 mils, less than 4.1 mils, less than 2.9 mils, less than 2 mils, or less than 1.4 mils. With respect to the lower limit, the thickness of the facing layer may be greater than 1 mil, e.g., greater than 1.4 mils, greater than 2 mils, greater than 2.9 mils, greater than 4.1 mils, greater than 5.9 mils, greater than 8.4 mils, greater than 12 mils, greater than 17.2 mils, or greater than 24.5 mils. Greater thicknesses, such as greater than 35 mils, and lesser thicknesses, such as less than 1 mil, are also contemplated.

The ratio of the thickness of the top layer to the thickness of the embossed layer may for example be in the following range: 0.1 to 70, e.g., 0.1 to 5.1, 0.2 to 9.8, 0.4 to 18.9, 0.7 to 36.4, or 1.4 to 70. With respect to the upper limit, the thickness ratio of the facing layer to the embossed layer can be less than 70, e.g., less than 36.4, less than 18.9, less than 9.8, less than 5.1, less than 2.6, less than 1.4, less than 0.7, less than 0.4, or less than 0.2. With respect to the lower limit, the thickness ratio of the facing layer to the embossed layer can be greater than 0.1, e.g., greater than 0.2, greater than 0.4, greater than 0.7, greater than 1.4, greater than 2.6, greater than 5.1, greater than 9.8, greater than 18.9, or greater than 36.4. Higher ratios, e.g., greater than 70, and lower ratios, e.g., less than 0.1, are also contemplated.

The inventors have found that the relationship between the thickness of the facing layer and the thickness of the intermediate layer is critical to provide a sheet having advantageous properties that are particularly useful, for example, in outdoor traffic safety applications. It is important to protect the embossed layer and other underlying layers from environmental degradation associated with outdoor use by maintaining a sufficient facing layer thickness relative to the intermediate layer thickness. Additionally, if the intermediate layer thickness is not sufficiently large relative to the face layer thickness, the above-described benefits in visible crack mitigation are not significantly realized. The ratio of the thickness of the top layer to the thickness of the intermediate layer may for example be in the following range: 0.2 to 175, e.g., 0.2 to 11.6, 0.4 to 22.9, 0.8 to 45.1, 1.5 to 88.9, or 3 to 175. With respect to the upper limit, the thickness ratio of the facing layer to the intermediate layer can be less than 175, e.g., less than 88.9, less than 45.1, less than 22.9, less than 11.6, less than 5.9, less than 3, less than 1.5, less than 0.8, or less than 0.4. With respect to the lower limit, the thickness ratio of the facing layer to the intermediate layer may be greater than 0.2, e.g., greater than 0.4, greater than 0.8, greater than 1.5, greater than 3, greater than 5.9, greater than 11.6, greater than 22.9, greater than 45.1, or greater than 88.9.

Release liner

In some embodiments, a release liner is attached to the second adhesive layer. The release liner may function as a protective cover such that the release liner remains in place until the sheet is ready to be adhered to an object or surface. If a liner or release liner is included in the sheet, a variety of materials and configurations can be used for the liner. In many embodiments, the liner is paper or a paper-based material. In many other embodiments, the liner is a polymer film of one or more polymer materials. Typically, at least one face of the liner is coated with a release material, such as silicone or a silicone-based material. As will be appreciated in the art, the release-coated side of the liner is placed in contact with the otherwise exposed side of the second adhesive layer. Prior to applying the label to the target surface, the liner is removed, thereby exposing the adhesive side of the label. The liner may be in the form of a single piece. Alternatively, the pad may be in the form of a plurality of sections or panels.

Method

The present disclosure also relates to methods for producing the provided retroreflective sheeting. The method includes thermally embossing the embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer. Hot embossing may include feeding an embossing layer to an embossing tool, heating the layer to allow the pattern on the tool to be pressed into the embossing layer material, and then cooling the layer. In certain aspects, the thermal embossing forms retroreflective elements on a back side of the embossed layer and attaches a flexible face layer to an opposite front side of the embossed layer.

In some embodiments, the method comprises attaching a flexible backing layer to the back surface of the embossing layer. In certain aspects, connecting comprises sealing the flexible backing layer to a portion of the rear surface of the embossing layer to define a plurality of air gaps with the flexible backing layer and the retroreflective elements. In some embodiments, the method includes attaching a metallized layer to a back surface of the embossed layer. In certain aspects, the metallization layer is vacuum metallized. In certain aspects, the metallization layer is applied by sputtering or plasma coating.

The method further includes coating the intermediate layer with an adhesive. The first side of the intermediate layer is coated with a first adhesive layer and the second side of the intermediate layer is coated with a second adhesive layer. The intermediate layer and the adhesive layer together form a transfer tape that is then laminated to the backing layer or metallized layer of the sheet. In some embodiments, a release liner is also attached to the exposed face of the second adhesive layer.

Detailed description of the preferred embodiments

The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

Embodiment 1: a flexible retroreflective sheeting comprising: an embossing layer having a front surface and an opposing back surface, the opposing back surface comprising a plurality of retroreflective elements; a flexible backing layer in contact with the rear surface of the embossing layer; a first adhesive layer connected to the flexible backing layer opposite the embossed layer; a middle layer having an opacity greater than 40% and connected to the first adhesive layer opposite the flexible backing layer; and a second adhesive layer connected to the intermediate layer opposite the first adhesive layer.

Embodiment 2: the embodiment of embodiment 1 wherein the embossed layer has an embossed color and the interlayer has an interlayer color having a CIEDE2000 color difference from the embossed color of less than 20.

Embodiment 3: the embodiment of embodiment 1 wherein the embossed layer is transparent, wherein the flexible backing layer has a backing color and the interlayer has an interlayer color having a CIEDE2000 color difference from the embossed color of less than 20.

Embodiment 4: the embodiment according to any one of the embodiments of embodiments 1-3 wherein the intermediate layer comprises a cavitated film.

Embodiment 5: the embodiment of any of embodiments 1-4 wherein the flexible retroreflective sheeting has a tensile strain ranging from 30% to 200%.

Embodiment 6: the embodiment of any of embodiments 1-5, wherein the flexible retroreflective sheeting has a force-to-break in the range of 20lbf to 60 lbf.

Embodiment 7: the embodiment of any of the embodiments of embodiments 1-6, wherein the flexible retroreflective sheet has a Young's modulus ranging from 45ksi to 275 ksi.

Embodiment 8: the embodiment according to any one of the embodiments 1-7 wherein the intermediate layer has a thickness in the range of 0.2 mil to 4 mil.

Embodiment 9: the embodiment according to any one of the embodiments 1-8, wherein the embossed layer has a thickness in the range of 0.5 mils to 10 mils.

Embodiment 10: the embodiment according to any one of the embodiments 1-9, wherein the ratio of the embossed layer thickness to the intermediate layer thickness ranges from 0.1 to 20.

Embodiment 11: the embodiment according to any of the embodiments of embodiments 1-10 wherein the intermediate layer comprises one or more polymers selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefins, and polyurethanes.

Embodiment 12: the embodiment according to any one of the embodiments 1-11, wherein the flexible backing layer comprises one or more polymers selected from the group consisting of polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefins, and polyurethanes.

Embodiment 13: the embodiment according to any of the embodiments of embodiments 1-12 wherein the embossed layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, and polyurethanes.

Embodiment 14: the embodiment of any of embodiments 1-14 wherein the flexible backing layer is directly attached to a portion of the rear surface of the embossing layer, and wherein the flexible backing layer and the retroreflective elements define a plurality of air gaps.

Embodiment 15: the embodiment of any of embodiments 1-14 wherein the first adhesive layer and the second adhesive layer each independently comprise a pressure sensitive adhesive.

Embodiment 16: the embodiment according to any one of the embodiments of embodiments 1-15, further comprising: a flexible facing attached to the front surface of the embossing layer.

Embodiment 17: the embodiment of embodiment 16 wherein the flexible facing layer has a thickness in the range of 1 mil to 35 mils.

Embodiment 18: the embodiment of embodiment 16 or 17 wherein the ratio of the thickness of the flexible facing layer to the thickness of the embossing layer is in the range of 0.1 to 70.

Embodiment 19: the embodiment according to any one of the embodiments 16-18 wherein the ratio of the thickness of the flexible facing layer to the thickness of the intermediate layer ranges from 0.2 to 175.

Embodiment 20: the embodiment according to any one of the embodiments 16-19, wherein the flexible facing layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, polyolefins, and polyurethanes.

Embodiment 21: the embodiment according to any one of the embodiments of embodiments 1-20, further comprising: a release liner adhered to the second adhesive layer opposite the intermediate layer.

Embodiment 22: the embodiment according to any of the embodiments of embodiments 1-21, wherein the flexible backing layer has a backing color, and wherein the intermediate layer has an opacity of greater than 58% and an intermediate layer color having a CIEDE2000 color difference from the backing color of less than 10.

Embodiment 23: the embodiment of any of the embodiments of embodiments 1-22 wherein the intermediate layer has an opacity of greater than 58% and wherein the flexible retroreflective sheeting has a tensile strength ranging from 30% to 150%.

Embodiment 24: the embodiment of any of the embodiments of embodiments 1-23, wherein the flexible backing layer has a backing color, wherein the interlayer has an interlayer color having a CIEDE2000 color difference from the backing color of less than 10, and wherein the flexible retroreflective sheeting has a tensile strength ranging from 30% to 150%.

Embodiment 25: a method for producing a flexible retroreflective sheeting, the method comprising: thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer; attaching a flexible backing layer to a rear surface of the embossing layer; coating a first side of an intermediate layer with a first adhesive layer and an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape; and laminating the transfer tape to the flexible backing layer opposite the embossed layer.

Embodiment 26: the embodiment of embodiment 25 wherein the attaching comprises sealing the flexible backing layer to a portion of the rear surface of the embossed layer such that a plurality of air gaps are defined by the flexible backing layer and the retroreflective elements.

Embodiment 27: the embodiment of embodiment 25 or 26, wherein the thermal embossing further attaches a flexible facing layer to the front surface of the embossed layer opposite the back surface of the embossed layer.

Embodiment 28: the embodiment according to any one of the embodiments of embodiments 25-27, further comprising: attaching a backing layer to the second adhesive layer opposite the intermediate layer.

Embodiment 29: a flexible retroreflective sheeting comprising: an embossing layer having a front surface and an opposing back surface, the opposing back surface comprising a plurality of retroreflective elements, wherein the embossing layer has an embossed color; a metallized layer directly on a rear surface of the embossed layer; a first adhesive layer connected to the metallized layer opposite the embossed layer; an interlayer connected to the first adhesive layer opposite the metallized layer, wherein the interlayer has an opacity of greater than 40% and an interlayer color having a CIEDE2000 color difference from the embossed color of less than 20; and a second adhesive layer connected to the intermediate layer opposite the first adhesive layer.

Embodiment 30: the embodiment of embodiment 29 wherein the intermediate layer comprises a cavitated film.

Embodiment 31: the embodiment of embodiment 29 or 30 wherein the flexible retroreflective film has a tensile strain ranging from 30% to 200%.

Embodiment 32: the embodiment of any of the embodiments 29-31, wherein the flexible retroreflective film has a breaking force ranging from 20lbf to 60 lbf.

Embodiment 33: the embodiment of any of the embodiments of embodiments 29-32, wherein the flexible retroreflective film has a young's modulus ranging from 45ksi to 275 ksi.

Embodiment 34: the embodiment according to any one of the embodiments 29-33, wherein the intermediate layer has a thickness in the range of 0.2 mil to 4 mil.

Embodiment 35: the embodiment of embodiments 29-34 wherein the embossed layer has a thickness in the range of 0.5 mils to 10 mils.

Embodiment 36: the embodiment according to any one of the embodiments 29-35, wherein the ratio of the thickness of the embossed layer to the thickness of the intermediate layer ranges from 0.1 to 20.

Embodiment 37: the embodiment according to any one of the embodiments of embodiments 29-36, wherein the intermediate layer comprises one or more polymers selected from the group consisting of polyethylene terephthalate, polyvinyl chloride, polycarbonate, ethylene vinyl acetate, polyolefins, and polyurethanes.

Embodiment 38: the embodiment according to any one of the embodiments of embodiments 29-37, wherein the embossed layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, and polyurethanes.

Embodiment 39: the embodiment of any of the embodiments 29-38 wherein the retroreflective elements are metallized.

Embodiment 40: the embodiment of any of the embodiments 29-39 wherein the first adhesive layer and the second adhesive layer each independently comprise a pressure sensitive adhesive.

Embodiment 41: the embodiment according to any one of the embodiments of embodiments 29-40, further comprising: a flexible facing attached to a front surface of the embossed layer.

Embodiment 42: the embodiment of embodiment 41 wherein the flexible facing has a thickness in the range of 1 mil to 35 mils.

Embodiment 43: the embodiment of embodiment 41 or 42 wherein the ratio of the flexible facing thickness to the embossing layer thickness is in the range of 0.1 to 70.

Embodiment 44: the embodiment according to any one of the embodiments 41-43, wherein the ratio of the thickness of the flexible facing layer to the thickness of the intermediate layer ranges from 0.25 to 175.

Embodiment 45: the embodiment according to any of the embodiments 41-44, wherein the flexible facing layer comprises one or more polymers selected from the group consisting of acrylics, polycarbonates, polyolefins, and polyurethanes.

Embodiment 46: the embodiment according to any one of the embodiments of embodiments 29-45, further comprising: a release liner adhered to the second adhesive layer opposite the intermediate layer.

Embodiment 47: the embodiment according to any one of the embodiments of embodiments 29-46, wherein the interlayer has an opacity of greater than 58% and an interlayer color having a CIEDE2000 color difference from the embossed color of less than 10.

Embodiment 48: the embodiment of any of the embodiments 29-47, wherein the intermediate layer has an opacity of greater than 58%, and wherein the flexible retroreflective sheeting has a tensile strength ranging from 30% to 150%.

Embodiment 49: a method for producing a flexible retroreflective sheeting, the method comprising: thermally embossing an embossing layer to form a plurality of retroreflective elements on a rear surface of the embossing layer; attaching a metallization layer directly to a back surface of the embossing layer; coating a first side of an intermediate layer with a first adhesive layer and an opposing second side of the intermediate layer with a second adhesive layer, thereby forming a transfer tape; and laminating the transfer tape to the metallized layer opposite the embossed layer.

Embodiment 50: the embodiment of embodiment 49, wherein the thermal embossing further attaches a flexible facing layer to a front surface of the embossed layer opposite the back surface of the embossed layer.

Embodiment 51: the embodiment according to embodiment 49 or 50, further comprising: a release liner is attached to the second adhesive layer opposite the intermediate layer.

Embodiment 52: a method of applying a flexible retroreflective sheeting to a surface, the method comprising: providing a surface having an exterior face; providing a retroreflective sheeting according to any of the embodiments of embodiments 1-24 and 29-48; and bonding a second layer of the retroreflective sheeting to the outer face of the surface.

Embodiment 53: the embodiment of embodiment 52 wherein the surface comprises one or more polymers selected from the group consisting of polyvinyl chloride, linear low density polyethylene, high density polyethylene, and polycarbonate.

Embodiment 54: an article of manufacture, comprising: a surface having an exterior face; and the retroreflective sheeting of any of the embodiments 1-24 and 29-48 adhered to the outer face of the surface.

Embodiment 55: the embodiment of embodiment 54 wherein the surface comprises one or more polymers selected from the group consisting of polyvinyl chloride, linear low density polyethylene, high density polyethylene, and polycarbonate.

Examples

The disclosure will be better understood in view of the following non-limiting examples.

A series of retroreflective sheeting structures were assembled as shown in table 1 below. Each sheet includes a polyvinyl chloride (PVC) facing layer, a white acrylic embossing layer, and a PVC backing layer. Examples 1 and 2 included a clear interlayer sandwiched between two layers of S-9700 adhesive commercially available from Avery Dennison (Glendale, Calif.). Examples 3, 4 and 5 included a white colored intermediate layer between two S-9700 adhesive layers. Two comparative retroreflective sheeting structures were also prepared. The samples of comparative example a and comparative example B included a face layer, an embossed layer, and a backing layer similar to examples 1-5, but did not include an intermediate layer.

Each sheet structure was applied to a polyvinyl chloride traffic cone in the form of a top cone ring and a bottom cone ring. These cones were then tested by stepping on the cone ring in an indoor environment and after storing the cone at a temperature of 38 ° F for 2 hours, driving the cone ring twice with the car in an outdoor environment. The results from these fracture tests as well as the different tensile property tests are also presented in table 1 below.

The results in table 1 demonstrate that the inclusion of an intermediate layer in a flexible retroreflective sheeting, as described herein, better subjects the sheeting to the stress of a tread fracturing test that simulates a pedestrian colliding with a traffic safety device, such as a traffic cone. The results further demonstrate that color matching of the middle layer of the sheet structure to the embossed layer allows the sheet to minimize or prevent the formation of visible cracks at the higher forces of an automotive fracture test simulating a vehicle impact.

Although the present disclosure has been described in detail, modifications within the spirit and scope of the disclosure will be apparent to those skilled in the art. In view of the foregoing discussion, the relevant knowledge in the art, and the references discussed above in connection with the background and the embodiments, the disclosures of which are incorporated herein by reference. Additionally, it should be understood that various aspects of the invention as well as portions and various features of the various embodiments described below and/or in the appended claims may be combined or interchanged either in whole or in part. In the above description of various embodiments, those embodiments relating to another embodiment may be combined with other embodiments as appropriate, as will be understood by those skilled in the art. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.