Thermochromatic temperature marking for outdoor surfaces

Abstract

The present invention relates to a system, method, and composition for a thermochromatic, color indicative sheet or device that is bonded to an article such as a concrete or asphalt surface, a traffic sign, a plate of a guidepost and on which is indicated a surface temperature near or below the freezing point of water. The invention can also utilize an adhesive system including a pressure sensitive adhesive (PSA) and/or thermal sensitive adhesive sheet for adhering sheets of preformed thermoplastic with the thermochromatic color indicative sheet to concrete, asphalt, wood or composite material surfaces. The invention includes methods of applying the product allowing for immediate use in a traffic area upon completion of the application to any appropriate outdoor surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a pre-formed thermochromatic thermoplastic sheet with a surface layer marking that is adhered directly to the substrate with or without the use of a sealer.

FIG. 2 is a cross-sectional view of a pre-formed thermochromatic thermoplastic sheet with an adhesive composition integrally attached to the thermochromatic thermoplastic sheet with or without the use of sealer.

FIG. 3 is a cross-sectional view of a pre-formed thermochromatic thermoplastic sheet with a protective sheet and pressure sensitive adhesive composition integrally attached to the thermochromatic thermoplastic sheet with or without the use of sealer.

FIG. 4A and FIG. 4 B are photographs of an actual thermochromatic surface in a working example of the inventive article illustrating the difference between sub-freezing (FIG. 4B) and above freezing (FIG. 4A) ambient temperature conditions.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of a preformed thermochromatic thermoplastic sheet [5] which includes a bottom side [10] and a top side [12] that preferably has an aggregate [15] embedded in the top side [12] along with a patterned display or marker. The preformed thermochromatic thermoplastic sheet [5] is comprised of various thermoplastic formulations in specific patterns which can both change colors and hue intensity in response to temperature changes. The preformed thermochromatic thermoplastic sheet [5] may be comprised of multiple segments such as segment A [19] and segment B [18] that may be abutted or adjacent to additional segments. The preformed thermochromatic thermoplastic sheet [5] contacts the application surface [50], such as a bituminous or Portland concrete/cement surface, to provide permanent pedestrian and traffic control markings directly and is adhered to the application surface [50] without the use of a sealer. Heat, preferably from about 400 degrees F. to about 425 degrees F., may be used to aid in adhesion by melting the preformed thermochromatic thermoplastic sheet [5] directly to the application surface [50].

In another embodiment, adhesion to the application surface of the preformed thermochromatic thermoplastic sheet [5] is accomplished with a polyurea epoxy primer in a one or two-step operation such as adding a primer to the application surface [50], applying the preformed thermochromatic thermoplastic sheet [5] and heating or adding a primer to the application surface [50], applying the preformed thermochromatic thermoplastic sheet [5] and reheating both the preformed thermochromatic thermoplastic sheet [5] and the application surface [50].

FIG. 2 is a cross section view of a preformed thermochromatic thermoplastic sheet [5] adhered to an adhesive [30] of a high content binder formulation with a surface adhesive side [33] readily attachable to the application surface [50]. The surface adhesive side [33] contacts the application surface [50] forming an adhesive bond. Alternatively the application surface side adhesive side [33] may be an epoxy sealer which contacts the application surface [50] forming an adhesive bond and sealant where heat may be applied.

FIG. 3 is a cross sectional view of a preformed thermochromatic thermoplastic sheet [5] which includes a bottom side [10] and a top side [12] that preferably has an aggregate [15] embedded in the top side [12] along with a patterned display or marker. The preformed thermochromatic thermoplastic sheet [5] may be comprised of multiple segments such as segment A [19] and segment B [18] that may be abutted or adjacent to additional segments. The pressure sensitive adhesive [40] is in intimate contact with the preformed thermochromatic thermoplastic sheet [5] and a protective sheet [45] is removably adhered to the pressure sensitive adhesive [40] surface adhesive side [43]. The preformed thermochromatic thermoplastic sheet [5] is then moved to the application surface [50] at the desired location and the protective sheet [45] is peeled away to expose the surface adhesive side [43] to the application surface [50]. The surface adhesive side [43] thus contacts the application surface [50] forming an adhesive bond which is strengthened by application of pressure to the top surface [15].

FIG. 4A and FIG. 4B are photographs of an actual preformed thermochromatic thermoplastic sheet [5] top side [12] surface as a working example of an embodiment illustrating the surface [12] difference between above freezing (FIG. 4A) and sub-freezing (FIG. 4B) ambient temperatures. The surface temperature of the thermochromatic sheet is the temperature which is sensed and causes the indication.

As shown in FIG. 4A, the preformed thermochromatic thermoplastic sheet [5] retains an thermochromatic thermoplastic image [60] in a similar color, hue or tone as the surrounding non-thermochromatic thermoplastic area [55] when the temperature is above freezing (at or above 32 deg F. or 0 deg C.).

In FIG. 4B, an ambient temperature of 32 deg F. or 0 deg C. or below causes the thermochromatic thermoplastic image [60] to change color, hue or tone such that a detectable image [65] is easily seen in contrast to the surrounding non-thermochromatic thermoplastic area [55].

SUMMARY OF INVENTION

One embodiment of the present invention provides for a thermochromatic, color indicative sheet or device that can be directly bonded to an article such as a concrete or asphalt surface, a traffic sign, or a plate of a guidepost and on which can be indicated a surface temperature near or below the freezing point of water. This preformed thermochromatic road marking material includes the use of Thermochromatic Pigment Black Type-5 with 0 degrees Celsius color transition obtained from United Polymer Technology, LLC of Akron, Ohio. This product, with the special pigment produces a color change at a specified temperature (in this case at freezing—or 0 Celsius). The thermochromatic pigment can be used in concentrations of 1% to 20%, with the preferred formulation at or about 4%. A sealer may be used over the concrete or asphalt surface prior to adhesion of the thermochromatic sheet.

A second embodiment includes the use of an adhesive layer that may be heated with an appropriate heating system such that the adhesive layer enters a molten state on any appropriate surface (such as concrete or asphalt) prior to application of the thermochromatic marking surface directly over the molten adhesive layer. Again, the option to seal the surface prior to applying the adhesive layer exists.

A third embodiment of the present invention relates to a method for adhering the thermochromatic sheets that are hydrocarbon or alkyd thermoplastic in nature (generally known as thermoplastic signage) to an uncured concrete traffic surface to provide permanent pedestrian and traffic control markings. Traffic signage may be applied using this method preferably from about 24 hours to about 48 hours after pouring or shaping, although in many cases concrete may remain moist for longer periods due to the moisture content of the surrounding soil. For this embodiment there is no need for preheating of the pavement, or removal of laitance on portland cement concrete. The concrete or asphalt surface also may be sealed using this technique.

The third embodiment utilizes a low viscosity polyurea composition from about 100 centipoise to about 300 centipoise which allows rapid penetration into the pores of uncured concrete substrate surfaces. Without being bound by any particular theory, polyurea of the specified viscosity appears to penetrate through the moisture into the concrete substrate before curing.

The curative systems may also include amine-terminated chain extenders in the formulation. Suitable chain extenders include, but are not necessarily limited to aliphatic, aromatic and cycloaliphatic diamine chain extenders.

In addition to polyurea compositions, other curable systems of a sufficiently low viscosity to penetrate the concrete surface are selected from the group comprising one-and two-part epoxies, multi-component polyurethanes, silicone adhesives, UV/EB curable adhesives, UV/EB curable resins and combinations thereof.

All Portland cements are hydraulic cements that set and harden through a chemical reaction with water. During this reaction, called hydration, a node forms on the surface of each cement particle. The node grows and expands until it links up with nodes from other cement particles or adheres to adjacent aggregates.

It is during hydration that an applied low viscosity polyurea seeps into and is chemically reactively bonded to the concrete. An adhesive, thermoplastic, or preformed thermoplastic sheeting is placed over the polyurea/concrete substrate and heated to where the adhesive sheeting melts into the polyurea/concrete substrate becoming a semi-homogenius mixture. The thermochromatic signage can then be applied and smoothed or leveled over the semi-homogenious mixture and can then be heated to a temperature to melt the thermoplastic material into the semi-homogenious mixture, thereby creating a chemically reacted bonded layered product.

Heating of the surface of the thermochromatic signage and the adhesive layer may be accomplished by a heating means such as the FLINT 2000EX® heat gun, manufactured by Flint Trading, Inc., or can be accomplished with an open flame, a closed flame, by heated roller, electrically resistive heating or other means known to those skilled in the art.

The heat source is then removed from the thermoplastic signage and the mixture is allowed to cool thereby returning the mixture from a molten state to a semi-molten state and finally to a hardened state as one substance that includes the concrete substrate.

The re-application of heat, useful in particular, to bond the thermochromatic signage edges, will allow the edges to flow penetrating into the semi-homogeneous mixture and into the concrete providing stability toward mechanical damage (such as plows) and edge peeling.

The application of cool water after a heated state will hasten solidification, strengthening and curing of the mixture.

An additional embodiment of the present invention also relates to a system, method, and composition utilizing a pressure sensitive adhesive (PSA) and/or thermal sensitive adhesive sheet for adhering sheets of preformed decorative thermoplastic road markings combined with the thermochromatic color indicative sheet. The present invention includes achieving sufficient adhesion without requiring the use of specialized tools.

The preformed thermoplastic or thermoset may be alkyd or hydrocarbon based and includes a PSA (pressure sensitive adhesive) with one surface in contact with the thermoplastic sheet and the second side or surface correspondingly to be placed in contact with the concrete, asphalt, wooden or composite material surface.

In order to achieve semi-permanent or permanent adhesion of the pre-cut thermoplastic thermochromatic color indicating sheet, the typical user must purchase or rent a heating device of sufficient heat volume or contract with a business possessing specialized heating tools required.

It is therefore another object of the invention to provide a thermoplastic thermochromatic, color indicative sheet or device that may be applied without the requirement or use of specialized (heating or other) tools. The present invention describes a system, method and composition for creating, adhering and installing a preformed thermoplastic thermochromatic, color indicative sheet or device to a surface utilizing a pressure sensitive adhesive (PSA) without requiring the use of specialized tools.

Additionally, the present invention relates to a system, method and composition for utilizing an emulsion based, solid, single component, multiple component, or radiation curable pressure adhesive sheet composition that may require energy activation for adhering thermoplastic or preformed thermoplastic thermochromatic, color indicative sheet or device to various surfaces. One embodiment includes preferably, a PSA that is based on butyl moieties for the adhesion chemistry with a silicon sheet on one or both sides of the PSA composition.

The thermochromatic, color indicative sheet or device markings associated with the top surface of the preformed thermoplastic or thermoset sheets may be decorative or legend type markings or road indicia or the like.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the present invention relates to a system, method and a composition for adhering preformed thermoplastics that are hydrocarbon or alkyd based thermoplastics or thermosets with thermochromatic surfaces utilizing a pressure sensitive adhesive (PSA).

Such an embodiment of the present invention is described in terms of installation and implementation, with the following instructions for manufacturing and application using a pressure sensitive adhesive system;

Manufacturing Instructions:

a) Start with a preformed thermoplastic thermochromatic, color indicative sheet or device of the current invention.b) Cut the preformed sheet into decorative segments.c) Apply PSA silicon based sheets on one or both sides.d) Place segments adjacent to each other to form decorative/predetermined patterns.e) Join segments with PSA into one or several manageable pieces.f) Ship manageable pieces to the application site (and application surface where adhesion is required).

Application Instructions for the Present Invention:

Pressure Sensitive Preformed Thermochromatic Surfacing & Marking Material

General Information

ReadyMark™ is a durable horizontal and vertical surface overlay material suitable for horizontal signage, logos, slip proofing, and decorative surfacing of walkways, light traffic roadways, access routes, ramps, etc., located near on within residential and commercial buildings and facilities such as schools, hospitals, shopping malls, airports, bus terminals, train stations, etc. The material is equally suitable for concrete, asphalt, metal, glass, and plastic surfaces. ReadyMark™ consists of a solid sheet or a pattern of interconnected individual pieces of preformed thermoplastic material mounted on a sheet of pressure sensitive adhesive with a peel-off liner. The application procedure requires the use of a tamping roller, such as the use of the ReadyMark™ Roller. ReadyMark™ provides a wear-resistant, non-skid/non-slip, durable surface that can be used in traffic areas immediately after application is completed. The present invention utilizes a ReadyMark like backing, however, in this case, a thermochromatic, color indicative sheet is used as the top surface for indicating climate information.

Installation requirements are essentially identical to ReadyMark requirements as outlined below, but with the caveat that the top thermochromatic, color indicative sheet or device surface requires special attention and is used for bonding to an article such as a concrete or asphalt surface, a traffic sign, or a plate of a guidepost and on which is indicated a surface temperature near or below the freezing point of water. This preformed thermochromatic road marking material includes the use of Thermochromatic Pigment Black Type-5 with 0 C color transition obtained from United Polymer Technology, LLC of Akron, Ohio. This product, with the special pigment produces a color change at a specified temperature (in this case at freezing—or 0 Celsius). The thermochromatic pigment can be used in concentrations of 1% to 20%, with the preferred formulation at or about 4%.

General Requirements

The list of requirements below are provided to the user and are necessary to insure proper installation and longevity of the ReadyMark product with the addition of the thermochromatic top sheet.

• Moisture: It is important to ensure that no surface moisture is present prior to applying ReadyMark™ or ReadyMark™ Sealer to the application surface. The presence of moisture can be mitigated by taping a segment of dark plastic sheeting, approximately 18 in.×18 in., tightly to the surface, making sure that all edges are sealed with duct tape. A plastic sheet should be applied in an area where it is exposed to sunlight. After 20-30 minutes it is possible to get an early indication of the presence of moisture by lifting a corner of the plastic sheet and visually inspecting it for any moisture that may have accumulated on the underside of the sheet. FIG. 1 provides a visual rendition of this task. If no moisture is present, proceed to the second section entitled “Surface” below. If moisture is present the application should be completed at a later time when the surface is moisture free. It is not advisable to apply ReadyMark™ if a rainfall/spill has occurred within 24 hours or if the ambient humidity is greater than 80%.
• Surface: The application surface must be free of dirt, dust, chemicals and significantly oily substances. Concrete must be free of curing compounds and laitance. ReadyMark™ can be applied directly on very smooth clean surfaces (glazed ceramic tile, polished concrete, smooth metal, polished granite, etc.). On all other surfaces such as regular concrete, asphalt, granite, etc., ReadyMark™ Sealer must be applied before applying the ReadyMark™ material. It is not recommended to apply ReadyMark™ on top of top of paint, thermoplastic, cold plastic, or other types of floor surfacing materials and pavement coatings. The surface and ambient air temperature must be at least 50° F.
• Material: ReadyMark™ shall be kept dry at all times—in storage, in transit and on the project. Avoid extreme storage temperatures. ReadyMark™ should be stored in a building that is between 35° F. and 90° F. The packages should be stored flat and stacked a maximum of 25 packs high. The expected minimum shelf life for this product is 12 months.

Safety Precautions

ReadyMark™ Sealer is highly flammable. Skin and eye contact with the ReadyMark™ Sealer should be avoided by wearing protective equipment necessary including eye, and hand protection. Keep containers tightly sealed when not in use. The sealer should be kept out of the reach of children.

Application Procedure

The application area should be thoroughly cleaned. All loose particles, sand, dust, etc. must be removed. Utilize a power blower or compressed air if available, otherwise sweeping the surface completely clean should be adequate.

Ensure that no moisture is present. See “Moisture” under General Requirements (above).

All of the foregoing set of instructions and procedures should be used to provide a thermochromatic top sheet together with the ReadyMark adhesive system.

Claims

1. A roadway marker with a thermochromatic surface comprising; at least two preformed thermoplastic sections that include top sides and bottom sides wherein said thermochromatic surface is attached to said top sides and wherein said bottom side either includes an adhesive layer or no adhesive layer on a bottom side of said bottom sides thermoplastic sections, and wherein said sheeting is subsequently attached to a substrate.

2. The marker of claim 1, wherein said thermochromatic surface temperature is near or below the freezing point of water.

3. The marker of claim 1, wherein preformed thermochromatic road marking material is used for said thermochromatic sheet, wherein said sheet is color indicating and comprises a thermochromatic black pigment with a color transition at zero degrees Celsius, therein producing a color change near or below the freezing point of water.

4. The marker of claim 3, wherein said thermochromatic pigment is used in concentrations of 1% to 20%, and most preferably at 4%.

5. The marker of claim 1, wherein said marker comprises more than one preformed thermoplastic section which can be matched with at least one other preformed thermoplastic section such that said thermochromatic surface layer provides a desired pattern.

6. A method for providing a roadway marker with a thermochromatic surface comprising; at least two preformed thermoplastic sections that include top sides and bottom sides wherein said thermochromatic surface is attached to said top sides and wherein said bottom side either includes an adhesive layer or no adhesive layer on a bottom side of said bottom sides thermoplastic sections, and wherein attaching said sheeting to a substrate is accomplished by pressure, heat, or any useful form and combination of heat and or pressure.

7. The method of claim 6, wherein said thermochromatic surface temperature is near or below the freezing point of water.

8. The method of claim 6, wherein using preformed thermochromatic road marking material for said thermochromatic sheet is accomplished and wherein said sheet is color indicating and comprises a thermochromatic black pigment with a color transition at zero degrees Celsius, therein producing a color change near or below the freezing point of water.

9. The method of claim 6, wherein said thermochromatic pigment is used in concentrations of 1% to 20%, and most preferably at 4%.

10. The method of claim 6, wherein said marker comprises more than one preformed thermoplastic section matching with at least one other preformed thermoplastic section thereby providing thermochromatic surface layers with a desired pattern.

11. A system for coating or bonding or both coating and bonding a first underlying substrate, wherein a second substrate comprises a curable composition which is bonded to said first underlying substrate and wherein said curable composition includes a top surface with a thermochromatic thermoplastic sheet wherein said first and second substrate are further subjected to heating.

12. A system according to claim 11, wherein said first underlying substrate comprises uncured concrete.

13. A system according to claim 11, wherein said uncured concrete has been previously shaped and formed within about 24 hours to about 2 weeks.

14. A system according to claim 11, wherein said uncured concrete provides a moist, damp, or wet surface.

15. A system according to claim 11, wherein said first underlying substrate requires no laitance removal.

16. A system according to claim 11, wherein said first underlying substrate requires no preheating.

17. A system according to claim 11, wherein said first underlying substrate is any traffic surface.

18. A system according to claim 17, wherein said traffic surface is for pedestrian, motorized vehicles, aircraft, human powered conveyances, programmable robotics and the like.

19. A system according to claim 11, wherein said second substrate composition is comprised primarily of any curable epoxy including moisture curable epoxy.

20. A system according to claim 19, wherein said curable epoxy comprises a one part or multiple part composition or mixture and said mixture is optionally a isocyanate-functional prepolymer, an effective amount of terpene-phenolic resin, and an effective amount of a silane compound.

21. A system according to claim 19, wherein said curable epoxy comprises a one or two part epoxy, multi-component polyurethane, silicone adhesive, UV/EB curable adhesive, UV/EB curable resins, and combinations therereof.

22. A system according to claim 19, wherein said curable epoxy comprises a viscosity of about 10 centipoise to about 500 centipoise.

23. A system according to claim 19, wherein application of said curable epoxy is by brush, roller, sprayer or the like.

24. A system according to claim 19, wherein said curable epoxy remains uncured from about 1 minute to about 60 minutes.

25. A roadway marker with a thermochromatic adhesive backed sheeting comprising; at least two preformed thermoplastic sections of said sheeting that includes top sides and bottom sides with an adhesive layer on said bottom sides of said thermoplastic sections;and;a protective sheet covering said adhesive layer on said bottom sides;wherein said bottom sides and said protective sheets covering said adhesive layer of said bottom sides may be subsequently adhered to any suitable outdoor surface using at least pressure to provide adequate bond strength to ensure a proper permanent or semi-permanent or temporary surface covering said suitable outdoor surface and wherein the chemical composition of said adhesive is alkyl or butyl-based and wherein said top side is a thermochromatic, color indicative sheet or device that is bonded to a concrete or asphalt surface, a traffic sign, or a plate of a guidepost and upon which is indicated a surface temperature.and;a protective sheet for pressure sensitive adhesive only that covers said adhesive layer on said bottom sides.

26. The marker of claim 25, wherein said marker comprises a protective sheet and said protective sheet is preferably comprised of primarily a silicone elastomer or other silicone based thermoplastic.

27. The marker of claim 25, wherein said marker comprises more than one preformed thermoplastic section which can be matched with at least one other preformed thermoplastic section such that said a thermochromatic surface layer provides a desired pattern.

28. A method for providing a thermochromatic adhesive backed sheeting comprising; at least two preformed thermoplastic sections of said sheeting that includes top sides and bottom sides with an adhesive layer on said bottom sides of said thermoplastic sections;and;a protective sheet covering said adhesive layer on said bottom sides;wherein said bottom sides and said protective sheets covering said adhesive layer of said bottom sides may be subsequently adhered to any suitable outdoor surface using at least pressure to provide adequate bond strength to ensure a proper permanent or semi-permanent or temporary surface covering said suitable outdoor surface and wherein the chemical composition of said adhesive is alkyl or butyl-based and wherein said top side is a thermochromatic, color indicative sheet or device that is bonded to a concrete or asphalt surface, a traffic sign, or a plate of a guidepost and upon which is indicated a surface temperature.

29. The method of claim 28, wherein said marker comprises a protective sheet and said protective sheet is preferably comprised of primarily a silicone elastomer or other silicone based thermoplastic.

30. The method of claim 29, wherein said marker comprises more than one preformed thermoplastic section which can be matched with at least one other preformed thermoplastic section such that said a thermochromatic surface layer provides a desired pattern.

31. A system comprising providing an adhesive backed thermochromatic sheeting comprising; at least two preformed thermoplastic sections of said sheeting that includes top sides and bottom sides with an adhesive layer on said bottom sides of said thermoplastic sections;and;a protective sheet covering said adhesive layer on said bottom sides;wherein said bottom sides and said protective sheets covering said adhesive layer of said bottom sides may be subsequently adhered to any suitable outdoor surface using at least pressure to provide adequate bond strength to ensure a proper permanent or semi-permanent or temporary surface covering said suitable outdoor surface and wherein the chemical composition of said adhesive is alkyl or butyl-based and wherein said top side is a thermochromatic, color indicative sheet or device that is bonded to a concrete or asphalt surface, a traffic sign, or a plate of a guidepost and upon which is indicated a surface temperature.

32. The system of claim 31, wherein said sheeting comprises said protective sheet and said protective sheet is preferably comprised of primarily a silicone elastomer or other silicone based thermoplastic.

33. The system of claim 31, wherein said sheeting comprises more than one preformed thermoplastic section which can be matched with at least one other preformed thermoplastic section such that said a thermochromatic surface layer provides a desired pattern.