Paint replacement film, composites therefrom, and related methods

Abstract

Paint replacement films of the invention comprise at least one adhesive layer; at least one pigmented layer; and at least one polymer layer that is essentially free of low surface energy materials. In addition, paint replacement composite articles and related methods of the invention comprise a paint replacement film and a topcoat on a surface of the paint replacement film opposite the adhesive layer. Paint replacement films and composite articles of the invention are useful when applied to a variety of articles (e.g., a motorized vehicle such as an aircraft).

Claims

1. An article comprising at least three distinct layers in sequence as follows: at least one adhesive layer; a pigmented layer; and a polymer layer, wherein material comprising the polymer layer is selected to be chemically compatible with layers of the article adjacent to the polymer layer, wherein the article excluding the at least one adhesive layer has a thickness of about 25 microns to about 50 microns and is essentially free of fluoropolymer materials, wherein surface tension of each layer within the article is within about 5 dynes per centimeter of surface tension of layers of the article adjacent thereto, and wherein each of the at least one adhesive layer, the pigmented layer, and the polymer layer is covalently bonded to at least one other layer within the article to form a paint replacement film therefrom.

2. The article of claim 1, wherein the pigmented layer is discontinuous.

3. The article of claim 1, wherein the pigmented layer has a maximum thickness of about 25 microns.

4. The article of claim 1, wherein the pigmented layer has a thickness of about 5 microns to about 8 microns.

5. The article of claim 1, wherein the polymer layer is polyurethane-based.

6. The article of claim 1, wherein the polymer layer has a thickness of about 10 microns to about 50 microns.

7. The article of claim 1, wherein the polymer layer has a thickness of about 25 microns or less.

8. The article of claim 1, wherein the at least one adhesive layer comprises a pressure-sensitive adhesive.

9. The article of claim 1, wherein the at least one adhesive layer comprises a (meth)acrylate.

10. The article of claim 1, wherein the at least one adhesive layer has a thickness of about 5 microns to about 150 microns.

11. The article of claim 1, wherein the at least one adhesive layer has a thickness of about 30 microns to about 100 microns.

12. The article of claim 1, wherein the at least one adhesive layer has a thickness of about 25 microns or less.

13. The article of claim 1, wherein the pigmented layer has a maximum thickness of about 25 microns, wherein the polymer layer has a thickness of about 10 microns to about 50 microns, and wherein the polymer layer has a greater thickness than the pigmented layer.

14. An at least partially painted article comprising at least one surface having on at least a portion thereof the article of claim 1.

15. The at least partially painted article of claim 14, wherein the at least partially painted article comprises a motorized vehicle.

16. The at least partially painted article of claim 14, wherein the at least partially painted article comprises an aircraft.

17. A paint replacement composite article comprising: the article of claim 1, and a topcoat on a surface of the paint replacement film opposite the at least one adhesive layer.

18. The paint replacement composite article of claim 17, wherein the topcoat comprises a polyurethane-based material.

19. The paint replacement composite article of claim 17, wherein the topcoat comprises a clearcoat.

20. The paint replacement composite article of claim 17, wherein the topcoat is about 20 microns to about 40 microns thick.

21. A method of protecting a surface, the method comprising: adhering the article film of claim 1 to at least a portion of at least one exterior surface of an article to be protected, and applying a topcoat to essentially the entire exposed exterior surface of the article to be protected, except for those surfaces where the topcoat would detract from function of the underlying surface or article to be protected.

22. The method of claim 21, wherein the article to be protected comprises an aircraft.

23. An article comprising at least three distinct layers in sequence as follows: at least one adhesive layer; a pigmented layer, wherein the pigmented layer comprises ink; and a polymer layer, wherein the article excluding the at least one adhesive layer has a thickness of about 25 microns to about 50 microns and is essentially free of fluoropolymer materials, wherein surface tension of each layer within the article is within about 5 dynes per centimeter of surface tension of layers of the article adjacent thereto, and wherein each of the at least one adhesive layer, the pigmented layer, and the polymer layer is covalently bonded to at least one other layer within the article to form a paint replacement film therefrom.

24. An article consisting essentially of layers in sequence as follows: optionally, a release liner; at least one adhesive layer; a pigmented layer; a polymer layer, wherein material comprising the polymer layer is selected to be chemically compatible with layers of the article adjacent to the polymer layer; and optionally, a carrier, wherein the article excluding the at least one adhesive layer has a thickness of about 25 microns to about 50 microns and is essentially free of fluoropolymer materials, wherein surface tension of each layer within the article is within about 5 dynes per centimeter of surface tension of layers of the article adjacent thereto, and wherein each of the at least one adhesive layer, the pigmented layer, and the polymer layer is covalently bonded to at least one other layer within the article to form a paint replacement film therefrom.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(1) The phrase “paint replacement film” encompasses films including essentially one uniform color throughout as well as films which, by themselves or in combination with other paint replacement films, include graphics, patterns, and other non-uniformly dispersed color variations throughout. Paint replacement films of the invention generally include a polymer layer and an adhesive layer with a pigmented layer disposed therebetween and/or a pigmented layer disposed on the exterior surface of the polymer layer. The pigmented layer provides the uniform or non-uniform color throughout the film.

(2) In a preferred embodiment, the polymer layer, the pigmented layer, and the adhesive layer are selected to be chemically compatible with each other to improve interlayer adhesion of the paint replacement film. For example, material properties contributing to high chemical affinity of the various layers with each other are identified and selected according to this embodiment of the invention. According to one aspect of this embodiment, the surface tension of each layer within the paint replacement film is within about 5 dynes per centimeter of the surface tension of adjacent layers therein. According to another aspect of this embodiment, the chemistries of adjacent layers within the paint replacement film are selected such that covalent bonds form between the layers. Although primers may be used between adjacent layers, they are not required in paint replacement films according to the invention. Each of the layers is described in further detail below.

(3) Adhesive Layer

(4) While more than one adhesive layer can be used in paint replacement films of the invention or the adhesive layer can comprise more than one distinct adhesive, the following description is made with reference to one such layer and type of adhesive within that layer for simplicity only. Recognize that, if multiple adhesives or adhesive layers are used, each adhesive or adhesive layer can be the same or different.

(5) The adhesive layer comprises any suitable material. According to one embodiment, the adhesive layer generally comprises a base polymer with one or more additives. While any suitable chemistry can be used for the base polymer in the adhesive layer, (meth)acrylate (i.e., acrylate and methacrylate) chemistry is preferred. In particular, an adhesive based on 2-ethyl hexyl acrylate, vinyl acetate, and acrylic acid monomers polymerized as known to those skilled in the art can be used as the base polymer. However, other suitable chemistries are known to those skilled in the art and include, for example, those based on synthetic and natural rubbers, polybutadiene and copolymers thereof, polyisoprene and copolymers thereof, and silicones (e.g., polydimethylsiloxane and polymethylphenylsiloxane). In a preferred embodiment, the adhesive layer comprises a pressure-sensitive adhesive (PSA).

(6) Any suitable additives can optionally be used in conjunction with the base polymer in the adhesive layer. For example, stabilizers (e.g., antioxidants, heat stabilizers, and UV-stabilizers), crosslinkers (e.g., aluminum or melamine crosslinkers), corrosion inhibitors, tackifiers, plasticizers, photocrosslinkers, colorants, fillers, and other conventional adhesive additives as known to those of ordinary skill in the art can be incorporated into the adhesive layer. If desired, an adhesion promoter may be included in the adhesive layer. However, in preferred embodiments, the material comprising the adhesive layer is selected to be chemically compatible with adjacent layers of the paint replacement film. Thus, an adhesion promoter is not required according to preferred embodiments of the invention.

(7) Preferably, the adhesive layer is essentially free of components that may tend to migrate to the outer surface of the paint replacement film or to an interface therein, where such components may promote interlayer delamination or otherwise detrimentally affect the adherence of the paint replacement film to adjacent surfaces or layers. The adhesive layer is also preferably resistant to chemicals to which it may be exposed during use of the paint replacement film. For example, it is preferred that the adhesive layer is resistant to degradation by water and hydraulic fluids (e.g., those sold by TBM, Inc. of St. Louis, Mo. under Solutia, Inc.'s SKYDROL trade designation).

(8) The adhesive layer comprises any suitable thickness. In one embodiment, the adhesive layer has a thickness of about 5 microns to about 150 microns. In a further embodiment, the adhesive layer has a thickness of about 30 microns to about 100 microns. In an exemplary embodiment, the adhesive layer is about 25 microns thick or less. However, the thickness of the adhesive layer can vary substantially without departing from the spirit and scope of the invention.

(9) Pigmented Layer

(10) While more than one pigmented layer can be used in paint replacement films of the invention, the following description is made with reference to one such layer for simplicity only. Recognize that, if multiple pigmented layers are used, each pigmented layer can be the same or different.

(11) The pigmented layer comprises any suitable material and provides desired aesthetics when the paint replacement film is adhered to a surface. The pigmented layer can be a continuous or discontinuous layer. Note that the pigmented layer may consist essentially of graphics, patterns, and the like, which results in the layer being a discontinuous layer and/or a non-planar layer.

(12) In an exemplary embodiment, the pigmented layer comprises ink. Any suitable commercially available ink can be used. Non-limiting examples of suitable inks include pigmented acrylic ink (including pigmented fast-dry acrylic ink), pigmented urethane ink, epoxy ink, and a urethane enamel coating such as that sold by PRC Desoto International, Inc. of Glendale, Calif. under the trade designation, DESOTHANE HS.

(13) The pigmented layer generally comprises at least one material imparting desired color to the layer or portion thereof. Any suitable additives can optionally be used in the pigmented layer. For example, stabilizers (e.g., antioxidants, heat stabilizers, and UV-stabilizers), crosslinkers (e.g., aluminum or melamine crosslinkers), corrosion inhibitors, plasticizers, photocrosslinkers, additional colorants, fillers, and other conventional additives as known to those of ordinary skill in the art can be incorporated into the pigmented layer. If desired, an adhesion promoter may be included in the pigmented layer. However, in preferred embodiments, the material comprising the pigmented layer is selected to be chemically compatible with adjacent layers of the paint replacement film. Thus, an adhesion promoter is not required according to preferred embodiments of the invention.

(14) Preferably, the pigmented layer is essentially free of components that may tend to migrate to the outer surface of the paint replacement film or to an interface therein, where such components may promote interlayer delamination or otherwise detrimentally affect the adherence of the paint replacement film to adjacent surfaces or layers. The pigmented layer is also preferably resistant to chemicals to which it may be exposed during use of the paint replacement film. For example, it is preferred that the pigmented layer is resistant to degradation by water and hydraulic fluids (e.g., those sold by TBM, Inc. of St. Louis, Mo. under Solutia, Inc.'s SKYDROL trade designation), particularly when the pigmented layer comprises an outer layer of the paint replacement film.

(15) The pigmented layer comprises any suitable thickness. In an exemplary embodiment, the pigmented layer has a maximum thickness of about 25 microns, preferably about 5 microns to about 8 microns.

(16) Polymer Layer

(17) While more than one polymer layer can be used in paint replacement films of the invention or the polymer layer can comprise more than one distinct polymer, the following description is made with reference to one such layer and type of polymer within that layer for simplicity only. Recognize that, if multiple polymers or polymer layers are used, each polymer or polymer layer can be the same or different.

(18) The polymer layer comprises any suitable material. For example, the polymer layer may comprise a urethane film, an acrylic film, an epoxy film, or a polyester film (e.g., that available from DuPont under the MYLAR trade designation). Although generally not preferred due to its lack of flexibility, the polymer layer can also be a vinyl, such as polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), or general polyvinyl fluoride (PVF) (e.g., that available from DuPont under the TEDLAR trade designation). Nevertheless, generally the polymer layer is essentially free of low surface energy materials (e.g., silicones and fluoropolymers), which tend to promote interlayer delamination.

(19) The polymer layer is preferably polyurethane-based in that it comprises any suitable polyurethane material. For simplicity, the term “polyurethane” is sometimes used herein to reference polymers containing urethane (also known as carbamate) linkages, urea linkages, or combinations thereof (i.e., in the case of poly(urethane-urea)s). Thus, polyurethanes of the invention contain at least urethane linkages and, optionally, urea linkages. Many commercially available polyurethanes are available and suitable for use as polyurethane-based polymer layers according to the invention. For example, polyurethanes are available from Thermedics (Noveon, Inc.) of Wilmington, Mass. under the TECOFLEX trade designation (e.g., CLA-93AV) and from Bayer MaterialScience LLC of Pittsburgh, Pa. under the TEXIN trade designation (e.g., an aliphatic, ester-based polyurethane available under the trade designation, TEXIN DP7-3008).

(20) Any suitable additives can optionally be included in the polymer layer. For example, stabilizers (e.g., antioxidants, heat stabilizers, and UV-stabilizers), crosslinkers (e.g., aluminum or melamine crosslinkers), binders, corrosion inhibitors, plasticizers, photocrosslinkers, colorants, fillers, and other conventional additives as known to those of ordinary skill in the art can be incorporated into the polymer layer. If desired, an adhesion promoter may be included in the polymer layer. However, in preferred embodiments, the material comprising the polymer layer is selected to be chemically compatible with adjacent layers of the paint replacement film. Thus, an adhesion promoter is not required according to preferred embodiments of the invention.

(21) The polymer layer may be clear or pigmented depending on the application. When the polymer layer is clear, the pigmented layer is typically provided between the polymer layer and the adhesive layer. Alternatively or in conjunction with another pigmented layer, when the polymer layer is clear, a pigmented layer can be provided on the outer surface of the polymer layer. When the polymer layer is pigmented, the pigmented layer is generally provided on the outer surface of the polymer layer. In this embodiment, the polymer layer can be impregnated with a material (e.g., titanium dioxide) that causes the polymer layer to function as a reflective background, bringing out the color of the overlying pigmented layer.

(22) Preferably, the polymer layer is essentially free of components that may tend to migrate to the outer surface of the paint replacement film or to an interface therein, where such components may promote interlayer delamination or otherwise detrimentally affect the adherence of the paint replacement film to adjacent surfaces or layers. The polymer layer is also preferably resistant to chemicals to which it may be exposed during use of the paint replacement film. For example, it is preferred that the polymer layer is resistant to degradation by water and hydraulic fluids (e.g., those sold by TBM, Inc. of St. Louis, Mo. under Solutia, Inc.'s SKYDROL trade designation). It is also preferred that the polymer layer is thermally resistant to temperatures to which it may be exposed during use of the paint replacement film. For example, exterior surfaces or coverings of an aircraft are often exposed to temperatures ranging from about −55° C. to about +75° C. Thus, it is preferred that the polymer layer is resistant to degradation when exposed to such temperature variations.

(23) The polymer layer comprises any suitable thickness. In one embodiment, the polymer layer has a thickness of about 10 microns to about 50 microns. In an exemplary embodiment, the polymer layer is about 25 microns thick or less. It has been found that use of a relatively thin polymer layer contributes to superior flexibility of the paint replacement film. Such flexibility allows paint replacement films of the invention to be effectively used in covering articles (e.g., aircraft) having curved or other non-planar surfaces.

(24) Optional Topcoat

(25) According to a preferred embodiment of the invention, a topcoat is applied to the exterior surface of the paint replacement film on a side opposite the adhesive. In this embodiment, the topcoat overlays the paint replacement film to form a paint replacement composite article.

(26) In one embodiment, a topcoat is applied (e.g., by spraying or painting it) on the paint replacement film after adherence of the paint replacement film to an underlying surface. Preferably, the topcoat is applied such that no paint replacement film is exposed to the environment when the composite article is adhered to a surface for use. Still further, when more than one paint replacement film is used in combination with others on a surface, the topcoat preferably covers and protects seams between adjacent paint replacement films from exposure to the environment.

(27) The topcoat can comprise any suitable chemistry. In general, the topcoat provides one or more properties including the following: environmental resistance, chemical resistance, abrasion resistance, scratch resistance, optical transparency, and other often desirable properties. According to an exemplary embodiment, the topcoat comprises a material with the following properties: non-yellowing, gloss retention (e.g., maintaining of gloss on the order of about 80 to about 90 gloss units), and extensibility.

(28) In an exemplary embodiment, the topcoat comprises a polyurethane-based material. Many suitable topcoats are commercially available, including for example, polyurethane coatings sold by PRC Desoto International, Inc. of Glendale, Calif. under the DESOTHANE HS trade designation (e.g., DESOTHANE HS BAC 900 (CA8000/B900A or CA8000/B900B)) or those sold by Akzo-Nobel Aerospace Coatings of Waukegan, Ill. under the ECLIPSE trade designation (e.g., ECLIPSE BAC 900).

(29) Preferably, chemistry of the topcoat is selected to facilitate its bonding to the underlying paint replacement film. According to one aspect of this embodiment, the surface tension of the outer layer of the paint replacement film is within about 5 dynes per centimeter of the surface tension of the overlying topcoat. According to another aspect of this embodiment, the topcoat comprises excess isocyanate-functional moieties reactive with excess isocyanate-reactive moieties in the exterior layer of the paint replacement film on which it is applied. According to this aspect of the invention, covalent bonds form between the topcoat and paint replacement film. Such covalent bonds are typically more robust than other types of bonds (e.g., those relying on Van Der Waals forces, such as those typically associated with use of pressure sensitive adhesives) and are, therefore, preferred.

(30) Any suitable additives can optionally be included in the topcoat. For example, stabilizers (e.g., antioxidants, heat stabilizers, and UV-stabilizers), crosslinkers (e.g., aluminum or melamine crosslinkers), binders, corrosion inhibitors, plasticizers, photocrosslinkers, colorants, fillers, and other conventional additives as known to those of ordinary skill in the art can be incorporated into the topcoat. The topcoat layer may be clear or pigmented depending on the application. When clear, which is preferred so that the pigmented layer is outwardly visible, the topcoat is referred to as a “clearcoat.”

(31) As applied, the topcoat is preferably resistant to chemicals to which it may be exposed during use of the paint replacement composite article. For example, it is preferred that the topcoat is resistant to degradation by water and hydraulic fluids (e.g., those sold by TBM, Inc. of St. Louis, Mo. under Solutia, Inc.'s SKYDROL trade designation). It is also preferred that the topcoat is thermally resistant to temperatures to which it may be exposed during use of the paint replacement composite article. For example, exterior surfaces or coverings on an aircraft are often exposed to temperatures ranging from about −55° C. to about +75° C. Thus, it is preferred that the topcoat is resistant to degradation when exposed to such temperature variations.

(32) The topcoat is applied on the exterior surface of the paint replacement film to a desired thickness according to coating methodology known to those skilled in the art. In an exemplary embodiment, the total dry thickness of the applied topcoat is about 10 microns to about 60 microns, preferably about 20 microns to about 40 microns. Depending on the desired thickness, the topcoat can be applied in one or more coating layers. For example, two individual coating layers comprise the topcoat according to one embodiment. In this embodiment, each coating layer is sprayed wet, but not so wet as to flow unevenly across the surface and create a significantly non-uniform topcoat.

(33) While this embodiment employing a topcoat is described with reference to the improved paint replacement films of the invention, recognize that this aspect of the invention is applicable to use with any conventional paint replacement film or similar underlying material.

(34) Applications

(35) Until the paint replacement film is adhered to a surface, it can be stored with an optional release liner adjacent the adhesive layer and with an optional carrier on the opposite side thereof. The selection and use of such carriers and liners is within the knowledge of one of ordinary skill in the art.

(36) When applied, paint replacement films can cover substantially all of or select portions of exterior surfaces on a variety of articles, such as transportation vehicles. The paint replacement film can be applied to a surface according to principles and methodologies understood by those of ordinary skill in the art. For example, the release liner, if present, is first removed. Then, the surface to which the paint replacement film is to be adhered can optionally be sprayed with a cleaning and/or anti-slip agent (e.g., a mixture of 3 parts water to 1 part isopropanol). The adhesive layer of the paint replacement film may also be sprayed with such an agent. Still further, once the paint replacement film is positioned over the surface to which it is to be applied, the film may also be sprayed with such an agent. Thereafter, the paint replacement film is firmly adhered to the underlying surface using, for example, a squeegee. Excess cleaning and/or anti-slip agent is then removed from the surface and the film is allowed to set for a time sufficient to prevent inadvertent removal of the film upon removal of any carrier used in conjunction therewith. The carrier, if present, is then removed.

(37) After they are adhered to a surface as known to those of ordinary skill in the art, an exemplary method of which is described above, the optional topcoat is applied in one embodiment. If desired, the outer layer of the paint replacement film is primed with a cleaning agent (e.g., a mixture of 3 parts water to 1 part isopropanol) to remove any contamination before the optional topcoat is applied.

(38) Recognize that, when used, the topcoat may be applied over a discrete portion of the paint replacement film adhered to a surface. It is preferred, however, that the topcoat is applied to encapsulate essentially all of the paint replacement film. When applied to an aircraft, for example, it is particularly preferred to apply the topcoat to essentially the entire exposed surface of the aircraft, except for those surfaces where the topcoat would detract from the function of the underlying surface (e.g., as in the case of windows, which may be taped or otherwise covered during application of the topcoat to prevent coating thereof).

(39) Paint replacement films of the invention are useful for application to a wide variety of exterior surfaces. For example, such paint replacement films find particularly beneficial use when adhered to exterior surfaces of many transportation vehicles. In an exemplary embodiment, paint replacement films of the invention are effectively and durably adhered to the exterior surface of an airborne transportation vehicle, which vehicles are typically subject to extreme wind resistance and other challenging environmental conditions when in use. For example, the paint replacement films are capable of being effectively and durably adhered to the exterior surface of an aircraft. The paint replacement films are also capable of being efficiently removed from the surface of an aircraft when repair is needed due to the increased interlayer adhesion, which promotes removability of the paint replacement film in a unitary piece when desired.

(40) Not only do paint replacement films of the invention exhibit improved resistance to interlayer delamination or inadequate adhesion during use, but they also have improved flexibility as compared to conventional paint replacement films. This flexibility, which is created in part due to the overall thin dimensions of the paint replacement film (e.g., about 25 microns to about 50 microns thick, not including the adhesive layer), facilitates adequate and durable adherence of the film to curved or otherwise non-planar surfaces.

(41) Use of such paint replacement films and related articles facilitates obtainment of many benefits as compared to use of traditional paint. These benefits include, for example, a reduction in VOC emissions generated during manufacture of the article to which such composite articles are applied, improved water conservation during such manufacture, decreased weight of the manufactured articles, more consistent surface quality (e.g., including consistent weight distribution throughout the surface onto which the paint replacement film is applied) in such manufactured articles, and other benefits.

EXAMPLES

(42) Exemplary embodiments and applications of the invention are described in the following non-limiting examples and related testing methods.

Example 1

(43) A paint replacement film was prepared with the following order of construction and dimensions: a 20-micron thick, clear polyurethane film, a pigmented layer comprising images and characters, a 30-micron thick acrylic adhesive, and a 160 grams per square meter (gsm) poly-coated kraft paper release liner. The paint replacement film was prepared for use on an aircraft. Once applied to the exterior surface of an aircraft, a clearcoat can be applied as described herein. For example, a topcoat (e.g., clearcoat) having a thickness of about 20 to about 40 microns can be wet-applied over the paint replacement film.

Example 2

(44) A paint replacement film was prepared with the following order of construction and dimensions: a 10-micron thick, clear polyurethane film, a pigmented layer comprising images and characters, a 15-micron thick acrylic adhesive, and a 160 grams per square meter (gsm) poly-coated kraft paper release liner. The paint replacement film was prepared for use on an aircraft. This film is preferred for application to portions of an aircraft with highly curved surfaces (e.g., engine nacelle). Once applied to the exterior surface of an aircraft, a clearcoat can be applied as described herein. For example, a topcoat (e.g., clearcoat) having a thickness of about 20 to about 40 microns can be wet-applied over the paint replacement film.

(45) Various modifications and alterations of the invention will become apparent to those skilled in the art without departing from the spirit and scope of the invention, which is defined by the accompanying claims. It should be noted that steps recited in any method claims below do not necessarily need to be performed in the order that they are recited. Those of ordinary skill in the art will recognize variations in performing the steps from the order in which they are recited.