Coating that allows laser removal of exterior livery on composites

Abstract

To provide a method and coating for protecting a surface of a non-metallic composite component.SOLUTION: A method comprises applying a protective coating layer to an exposed surface of a non-metallic composite component, the protective coating layer comprising: (a) a multilayer having at least one co-cured layer applied to a surface of the non-metallic composite component and at least one laser-sensitive layer applied to a surface of the co-cured layer, where the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties; or (b) a co-cured coating which comprises a laser-sensitive material incorporated therein to form a laser-sensitive co-cured layer applied to the surface of the non-metallic composite component, where the laser-sensitive material is selected from a reflective material, an optical sensor material, and a combination thereof, such that the non-metallic composite component will be protected from damage during subsequent laser ablation to remove an outer coating.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to methods and coatings for protecting the surfaces of non-metallic composite parts and also to enabling the removal of coatings from composite substrates. [Background technology]

[0002] Composite materials are used to construct numerous articles, such as aircraft fuselages. These articles are often adorned with outer livery, which is often decorative and indicates the branding of the article or aircraft. Over time, wear and branding changes can necessitate removing the outer livery on a composite part and adding new outer livery. Typically, chemical paint strippers (e.g., benzyl alcohol-based) or mechanical abrasion (e.g., sanding) are used to remove the outer livery. These methods can have undesirable effects on the underlying composite part. Sanding away the paint layer of the outer livery is time-consuming. The use of chemical paint strippers requires the application of an intermediate coat, which can swell when exposed to benzyl alcohol-based paint strippers, leading to increased paint flow, weight, and / or thickness. Furthermore, the application of chemical paint strippers requires multiple applications of the chemical agent during the stripping process and special containment of the chemical agent. A structure and process that overcomes these limitations is needed. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] SAE Standard MA4872A (2012) Summary of the Invention [Problem to be solved by the invention]

[0004] Structures and methods provided in accordance with one or more examples enable exterior coatings, such as decorative livery, to be removed from composite articles in a manner that reduces undesirable effects on the composite article compared to methods that use chemical paint strippers or mechanical abrasion. [Means for solving the problem]

[0005] Disclosed herein is a method for protecting the surface of a non-metallic composite part during laser ablation removal of an exterior coating by applying a protective coating layer to the surface of the non-metallic composite part to form a coated non-metallic composite part, and curing the coated non-metallic composite part. The protective coating layer comprises either (a) a multilayer having at least one co-cure layer applied to the surface of the non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cure layer (the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating comprising a laser-sensitive material (the laser-sensitive material is selected from a reflective material, an optical sensor material, and combinations thereof) contained therein to form a laser-sensitive co-cure layer applied to the surface of the non-metallic composite part.

[0006] Also disclosed is a method for removing an exterior coating from a non-metallic composite part by applying a protective coating layer to the surface of the non-metallic composite part, applying an exterior coating to the protective coating layer, and exposing the coated non-metallic composite part to a laser to remove the exterior coating. The protective coating layer comprises either (a) a multilayer having at least one co-cure layer applied to the surface of the non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cure layer (the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating comprising a laser-sensitive material (the laser-sensitive material is selected from a reflective material, an optical sensor material, and combinations thereof) contained therein to form a laser-sensitive co-cure layer applied to the surface of the non-metallic composite part.

[0007] According to one or more examples, a coated non-metallic composite part includes a protective coating layer applied to the non-metallic composite part and an exterior coating applied to the protective coating layer. The protective coating layer includes either (a) a multilayer structure including at least one co-cure layer applied to the surface of the non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cure layer (the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating including a laser-sensitive material (the laser-sensitive material is selected from a reflective material, an optical sensor material, and combinations thereof) incorporated therein to form a laser-sensitive co-cure layer applied to the surface of the non-metallic composite part. In one or more examples, the protective coating layer of the non-metallic composite part includes multiple layers, and the laser-sensitive layer applied to the surface of the co-cure layer is a reflective layer. In other examples, the protective coating layer includes multiple layers, and the laser-sensitive layer applied to the surface of the co-cure layer is an optical sensor layer. In one or more examples, the protective coating layer of the non-metallic composite part comprises a curable coating and the laser sensitive material contained therein is a reflective material. In other examples, the protective coating layer comprises a curable coating and the laser sensitive material contained therein is an optical sensor material.

[0008] The above-described features, functions, and advantages may be achieved independently in various instances and may be combined in other instances, and further details thereof may be understood with reference to the following description and drawings.

[0009] Various advantages of examples of the present disclosure will become apparent to those skilled in the art upon reading the following specification and the appended claims, taken in conjunction with the drawings described below. [Brief explanation of the drawings]

[0010] [Figure 1] 1A to 1E are diagrams showing examples of cross sections of coated non-metallic composite parts. [Figure 2]1 is an illustration of an example method of applying an exterior coating to a coated non-metallic composite part, ablating the exterior coating, and then applying a new exterior coating. [Figure 3] FIG. 1 is an illustration of an example of applying an exterior coating as the outer layer of a coated non-metallic composite part and then ablating the exterior coating to prepare the surface for subsequent coating application. [Figure 4] FIG. 1 is an illustration of an example of laser ablation of an exterior coating from a coated non-metallic composite part using a feedback loop to monitor the ablation. [Figure 5] FIG. 10 is an illustration of an example of laser ablating at least a portion of an exterior coating from a coated non-metallic composite part and then applying a new exterior coating using a feedback loop to monitor the ablation. [Figure 6] FIG. 1 is a schematic diagram of an example of protecting the surface of a non-metallic composite part during laser ablation of an exterior surface coating. [Figure 7] 1 is a schematic diagram of an example of removing an exterior coating from a coated non-metallic composite part. DETAILED DESCRIPTION OF THE INVENTION

[0011] It is to be understood that the examples described herein are merely illustrative of the application of the principles of the present disclosure, and reference to details of the illustrated examples does not limit the scope of the claims which recite essential features of the present disclosure.

[0012] Disclosed are methods and coatings for protecting the surface of a nonmetallic composite part during laser ablation removal of an exterior coating, such as decorative or non-decorative livery, comprising applying a protective coating layer to the surface of the nonmetallic composite part. The protective layer can have a multi-layer structure, with at least one laser-sensitive layer applied to a co-cured layer applied to the surface of the nonmetallic composite part before curing, the laser-sensitive layer being selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties. Alternatively, a laser-sensitive material can be combined with the co-cured layer by including the laser-sensitive material in the co-cured coating composition or formulation before application to the nonmetallic composite part and curing the composite. The laser-sensitive material can be selected from a reflective material, an optical sensor material, or a combination thereof. These configurations protect the nonmetallic composite part from damage during subsequent laser ablation to remove an exterior coating (such as a decorative or non-decorative coating) located as the outermost layer of the coated nonmetallic composite part.

[0013] Coatings of the present disclosure can be incorporated into composite manufacturing processes to protect non-metallic composite parts from laser ablation during removal of exterior coatings such as decorative livery. A coated non-metallic composite part is disclosed that includes a non-metallic composite part, a protective coating layer applied to the non-metallic composite part, and an exterior coating applied to the protective coating layer. The protective coating layer includes: (a) a multilayer having at least one co-cured layer applied to a surface of a non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, the laser-sensitive layer being selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties; (b) a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to the surface of the non-metallic composite part, the laser-sensitive material being selected from a reflective material, an optical sensor material, or a combination thereof.

[0014] The coated non-metallic composite part may have an exterior coating, such as decorative livery, applied to either (i) a laser-sensitive layer (wherein the laser-sensitive layer is one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties) or (ii) a laser-sensitive co-cured layer (wherein the laser-sensitive material is selected from a reflective material, an optical sensor layer, or a combination thereof to form a laser-sensitive co-cured reflective layer or a laser-sensitive co-cured optical sensor layer). The exterior coating may be non-decorative.

[0015] The coated non-metallic composite part 100 can be formed by applying a protective coating layer 300 to the non-metallic composite part 200. Applying the protective coating layer 300 can comprise (i) applying a co-cured layer 312 to the surface of the non-metallic composite part 200 and (ii) applying a laser-sensitive layer 311 to the surface of the co-cured layer 312, where the laser-sensitive layer is one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties. In other coated non-metallic composite parts 100, the protective coating layer 300 comprises applying a co-cured coating with a laser-sensitive material 320a contained therein to form a laser-sensitive co-cured layer 320 applied to the surface of the non-metallic composite part 200, where the laser-sensitive material 320a is selected from a reflective material, an optical sensor material, and combinations thereof.

[0016] The non-metallic composite part 200 comprises a composite material. The term "composite material" refers to a material made of two or more constituent materials, such as carbon fiber or other reinforcing fibers embedded in a polymer resin matrix. Specific fiber-reinforced composites comprise carbon-reinforced polymers, glass-reinforced polymers, or mixtures thereof. Fiber-reinforced composites comprise a polymer matrix. Fiber-reinforced composites may comprise bismaleimide, epoxy, benzoxazine, polyurethane, polycarbonate, polyester, polyurea, fluorourethane, acrylic, polysiloxane, polymer matrix. A particular coated non-metallic composite part comprises a non-metallic composite part comprising a carbon-reinforced polymer, a glass-reinforced polymer, or a mixture thereof, and a co-cured layer comprising polyurea, fluorourethane, polyester, acrylic, polycarbonate, polysilazane, a sol-gel coating, or an epoxy.

[0017] The term "outer coating" refers to decorative and non-decorative outer coatings, such as decorative and non-decorative livery.

[0018] The term "decorative livery" refers to the distinctive ornamentation, graphics, and symbols associated with a particular company, brand, or product.

[0019] The term "co-curable" refers to a composition or formulation that is capable of being cured.

[0020] The term "co-curable coating" refers to a polymeric coating or coating composition or formulation that is capable of being co-cured with other polymeric coatings or layers to form all or part of a coated non-metallic part.

[0021] The term "co-cured" refers to two or more layers or coatings that are cured simultaneously. Curing includes any method suitable for hardening polymers. Curing may involve one or more of thermal energy and moisture. Autoclaves and microwave systems are examples of equipment that can be used for curing.

[0022] The term "co-cured layer" refers to a polymer layer that is curable and / or cured along with a non-metallic composite layer and / or other polymer layers (such as protective coating layers) to form all or part of a coated non-metallic composite part. When either the term "co-cured layer" or "co-curable layer" is used, it is understood that the other example is also contemplated. Similarly, when either the term "co-cured coating" or "co-curable coating" is used, it is understood that the other example is also contemplated.

[0023] The term "laser-sensitive" refers to the property or characteristic of a material, coating, layer, film, etc. that is reflective, responsive, or activated by laser radiation or irradiation.

[0024] The term "new" in conjunction with an exterior coating refers to an exterior coating that is applied to a coated non-metallic composite part after removing any existing exterior coating.

[0025] In this application, when one of the terms "film," "coating," or "layer" is used, it should be understood that analogous examples are contemplated for the other terms. When one of the terms "film," "coating," or "layer" is used, it should be understood that the term "film," "coating," or "layer" can comprise a single or multiple "film," single or multiple "coating," or single or multiple "layer" configuration. For example, each co-cured layer, each laser-sensitive layer, each co-cured coating (comprising a laser-sensitive material), each base film, and each outer surface coating can comprise a single or multiple layers or coatings.

[0026] It should be understood that where one of the terms "body," "part," "substrate," or "article" is used in this application, analogous examples are contemplated for each of the remaining terms.

[0027] The terms used herein are for the purpose of describing particular examples only and are not intended to be limiting. In this application, the singular forms "a," "an," and "the" include the plural unless expressly stated otherwise. Furthermore, when used herein, the terms "comprise," "include," and "have" specify the presence of stated features, integers, steps, operations, elements, or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, or components, or combinations thereof.

[0028] Similarly, items joined by the terms "and" or "and" should not be read as requiring all items to be present in the set, but should be read as "and / or" unless otherwise specified. Similarly, items joined by the term "or" should not be read as requiring mutual exclusion within the set, but should be read as "and / or" unless otherwise specified. Furthermore, although items, elements, and components of the present disclosure may be described in the singular, the plural is also contemplated within the scope of the present disclosure unless specifically limited to the singular. The presence of expanders such as "one or more," "at least," and "not limited to" in some embodiments should not be read as implying that a narrower embodiment is contemplated or required in the absence of such expander. The use of the term "about" when referring to numerical values ​​or ranges is intended to include values ​​that account for experimental error that may occur when measurements are performed.

[0029] The non-metallic composite part 200 may include a surfacing film 400 or underlayer that forms the outer layer of the non-metallic composite part prior to the addition of the protective coating layer 300. The underlayer may function to provide a modified surface for bonding of additional layers or to provide a sealing function. For example, the underlayer may make the surface of the non-metallic composite part 200 smoother. In one or more examples, the underlayer 400 or underlayer is present between the non-metallic composite part and the co-cured layer 312. The underlayer 400 or underlayer may have the same polymer composition as the resin of the non-metallic composite part, or may have a different polymer composition. The polymer composition may include one or more polymers selected from epoxy, bismaleimide, benzoxazine, polyurethane, polycarbonate, polyester, polyurea, fluorourethane, acrylic, polysiloxane, and the like. The underlayer may also include fillers, such as pigments or conductive mesh.

[0030] Coatings can be reflective or designed to be optical sensors by selecting the absorptive / reflective properties of the material. Reflective materials reflect the laser light, preventing interaction between the laser and non-metallic composite parts. Optical sensor materials can be combined with a feedback loop that measures the surface in situ to determine when laser paint removal is complete and prevent interaction between the laser and the coating material.

[0031] The co-cured coating, with the laser-sensitive material 320a contained therein, provides a layer located between the non-metallic composite part 200 and the exterior coating 500. If the laser-sensitive material 320a is not contained in the co-cured layer, the co-cured layer 312 is located between the non-metallic composite part 200 and the laser-sensitive layer 311, which is one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties. The co-cured layer 312 may comprise polyurea, fluorourethane, polyester, acrylic, polycarbonate, polysilazane, a sol-gel coating, or epoxy. Sol-gel coatings include, but are not limited to, silicon-based sol-gels, such as alkoxysilanes, chlorosilanes, and Si—Zr glycidyl sol-gel (such as AC®-130 from Advanced Chemistry and Technology, Garden Grove, California), which is a combination of 3-glycidyloxypropyltrimethoxysilane (GTMS) and Zr(IV) n-propoxide reacted in the presence of an acid such as acetic acid. Alkoxysilanes include, but are not limited to, allyltrimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, isobutyl(trimethoxy)silane, n-propyltriethoxysilane, tetramethylorthosilicate, tetrapropylorthosilicate, triethoxy(octyl)silane, triethoxyphenylsilane, triethoxyvinylsilane, trimethoxymethylsilane, trimethoxyphenylsilane, and mixtures thereof. Chlorosilanes include, but are not limited to, butyltrichlorosilane, ethyltrichlorosilane, methyltrichlorosilane, pentyltrichlorosilane, and mixtures thereof.

[0032] The co-cure layer 312 may be applied to the non-metallic composite part 200 as a spray, powder, or film and then cured either simultaneously or separately from the curing of the non-metallic composite part 200. Having a separate layer minimizes and controls the impact on the co-cure layer 312 during laser ablation removal of the exterior coating 500.

[0033] When the laser-sensitive material 320a is selected from a reflective material, an optical sensor material, or a combination thereof and is contained in a layer separate from the cured layer 312, the reflective material or optical sensor material is contained in a suitable matrix material to disperse the reflective material, optical sensor material, or combination thereof, preventing degradation of film-forming properties and maintaining layer adhesion, corrosion protection, and other performance characteristics. In at least one example, a polymer matrix resin may be utilized. The polymer matrix resin may comprise polyurea, fluorourethane, polyester, acrylic, polycarbonate, polysilazane, a sol-gel coating, or an epoxy. Sol-gel coatings include, but are not limited to, silicon-based sol-gels, such as alkoxysilanes, chlorosilanes, and Si—Zr glycidyl sol-gel (e.g., AC®-130, manufactured by Advanced Chemistry and Technology, Inc., Garden Grove, California). The Si—Zr glycidyl sol-gel is a combination of 3-glycidyloxypropyltrimethoxysilane (GTMS) and Zr(IV) n-propoxide reacted in the presence of an acid, such as acetic acid. Alkoxysilanes include, but are not limited to, allyltrimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, isobutyl(trimethoxy)silane, n-propyltriethoxysilane, tetramethylorthosilicate, tetrapropylorthosilicate, triethoxy(octyl)silane, triethoxyphenylsilane, triethoxyvinylsilane, trimethoxymethylsilane, trimethoxyphenylsilane, and mixtures thereof. Chlorosilanes include, but are not limited to, butyltrichlorosilane, ethyltrichlorosilane, methyltrichlorosilane, pentyltrichlorosilane, and mixtures thereof. Similar to the co-cure layer 312, the co-cure coating has laser-sensitive material 320a contained therein, selected from reflective materials, optical sensor materials, and combinations thereof, and can be applied to the non-metallic composite part 200 as a spray, powder, or film, and then cured either simultaneously with or separately from the curing of the non-metallic composite part 200.

[0034] In certain coated non-metallic composite parts 100, the co-curable coating includes a laser-sensitive material 320a contained therein and has a surface adjacent to the non-metallic composite part 200 and a surface opposite the non-metallic composite part 200, with the laser-sensitive material 320a concentrated near the opposite surface of the non-metallic composite part 200. Concentrating the laser-sensitive material 320a near the surface of the co-cure layer minimizes damage to the laser-sensitive co-cure layer 320 during removal of the exterior coating 500. This is achieved by ensuring that the exterior coating 500 is removed at an earlier time than if the laser-sensitive material 320a were concentrated deep within the laser-sensitive co-cure layer 320 formed after curing the co-cure coating containing at least one laser-sensitive material 320a. In coated non-metallic composite parts 100, the protective coating layer 300 can include a reflective material. Alternatively, the protective coating layer 300 can include an optical sensor material. Alternatively, protective coating layer 300 may comprise a combination of both reflective and optical sensor materials, which may be a single material having both reflective and optical sensor properties, or at least two different materials, at least one of which is reflective and at least one of which is optical sensor material. In one or more examples, at least 90%, at least 80%, or at least 70% of laser-sensitive material 320a is located adjacent to the surface opposite the non-metallic surface of non-metallic composite part 200. Laser-sensitive material 320a may be positioned within a predetermined distance from the surface opposite the non-metallic surface of non-metallic composite part 200 to maintain an appropriate thickness of laser-sensitive coating layer 320 during the first laser ablation or paint removal cycle, preventing excessive loss of thickness due to laser ablation of laser-sensitive material 320a. For example, if the laser-sensitive material is metallic, the predetermined distance can be determined based on the original thickness of the laser-sensitive co-cured layer 320 before ablation and the thickness on the reflective material, optical sensor material, or a combination thereof, using known methods for measuring paints and / or polymers on metal surfaces. Alternatively, the laser-sensitive material 320a can be uniformly dispersed.

[0035] The laser-sensitive material 320a is at least one of a reflective material and an optical sensor material, including, but not limited to, metal flakes and ceramic flakes, such as, but not limited to, alumina flakes, stainless steel flakes, nickel flakes, and rare earth pigment flakes.

[0036] According to one or more examples, the laser-sensitive layer 311 of the protective coating layer 300 may include a reflective material and be referred to as a "reflective layer," or, if the reflective material is included in a curable coating to form the laser-sensitive cured layer 320 applied to the non-metallic composite part 200, a "reflective cured layer." The reflective layer or reflective cured layer functions to reflect laser light and prevent laser interaction with the underlying non-metallic composite part 200. In another example, the laser-sensitive layer 311 of the protective coating layer 300 may include an optical sensor material and be referred to as an "optical sensor layer," or, if the optical sensor material is included in a curable coating applied to the non-metallic composite part 200, a "optical sensor cured layer." The optical sensor material causes the optical sensor layer or optical sensor cured layer to provide a color change, a change in fluorescence, or light reflection to indicate that the exterior coating has been removed. A color change, fluorescence change, or reflection can alert the user that the outer layer has been removed and the protective layer has been reached, and the color change, fluorescence change, or reflection can be monitored by a sensing device coupled in a feedback loop.

[0037] The exterior coating 500 can be a decorative or non-decorative layer. In at least one example, the exterior coating 500 is a decorative coating. The exterior coating 500 can comprise a decal or a paint layer. Exterior coatings include, but are not limited to, applying multiple coatings to form a decorative coating. For decorative coatings, the coating can be applied by a process that uses a series of masking steps and then applying a colored paint or coating where desired. Other exterior coatings 500 are formed using inkjet methods to apply the decorative coating.

[0038] Disclosed herein is a method for protecting the surface of a non-metallic composite part 200 during removal of an exterior coating 500 by applying a protective coating layer 300 to the surface of a non-metallic composite part 200 to form a coated non-metallic composite part 100 and curing the coated non-metallic composite part 100, wherein the protective coating layer 300 comprises: (a) a multilayer 310 having at least one co-cured layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of the co-cured layer 312 (the laser-sensitive layer 311 is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties); or (b) a co-curable coating comprising a laser-sensitive material 320a (the laser-sensitive material 320a is selected from a reflective material, an optical sensor material, and combinations thereof) contained therein to form a laser-sensitive co-cured layer 320 applied to the surface of the non-metallic composite part 200. The method comprises: (a) (i) applying a co-curing layer 312 to the surface of the non-metallic composite part 200; and (ii) applying a laser-sensitive layer (the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties) to the surface of the co-curing layer 312; or (b) applying a co-curing coating comprising a laser-sensitive material 320a (the laser-sensitive material is selected from a reflective material, an optical sensor material, and a combination thereof) contained therein to form a laser-sensitive co-curing layer 320 applied to the surface of the non-metallic composite part 200; and (2) curing the coated non-metallic composite part 100.

[0039] The co-curing layer 312, or a co-curable coating containing the laser-sensitive material 320a, may be deposited on the non-metallic composite part 200 and cured.

[0040] If the reflective material, optical sensor material, or a combination thereof is present in a layer separate from the co-cured layer 312, the layers can be cured simultaneously or sequentially as the layers are applied.

[0041] The coated non-metallic composite part 100 may further comprise an exterior coating 500 applied to either (i) a laser-sensitive layer 311 (the laser-sensitive layer 311 is one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties) or (ii) a co-curable coating containing a laser-sensitive material 320a (the laser-sensitive material is selected from a reflective material, an optical sensor material, or a combination thereof). The method may further comprise removing at least a portion of the exterior coating 500 from the coated non-metallic composite part 100 using a laser ablation process.

[0042] Also disclosed herein is a method for removing an exterior coating 500 from a coated non-metallic composite part 100 without damaging the non-metallic composite part 200. The method comprises contacting a laser ablation device with the exterior coating 500, the coated non-metallic composite part 100 comprising the non-metallic composite part 200 and a protective coating layer 300, the protective coating layer 300 comprising either (a) a multilayer 310 having at least one co-cure layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of the co-cure layer 312 (the laser-sensitive layer 311 is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating comprising a laser-sensitive material 320a included to form a laser-sensitive co-cure layer 320 applied to the surface of the non-metallic composite part 200 (the laser-sensitive material 320a is selected from a reflective material, an optical sensor material, and combinations thereof). The protective coating layer 300 can comprise either (i) a co-cured layer 312 applied to the surface of the non-metallic composite part 200 and a laser-sensitive layer 311 applied to the surface of the co-cured layer 312 (the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (ii) a co-cured coating comprising a laser-sensitive material 320a (the laser-sensitive material 320a is selected from a reflective material, an optical sensor material, and combinations thereof) contained to form a laser-sensitive co-cured layer 320 applied to the surface of the non-metallic composite part 200. The exterior coating 500 can be present either (i) on the laser sensitive layer 311 (the laser sensitive layer 311 is one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties), or (ii) on a curable coating containing a laser sensitive material 320a (the laser sensitive material is selected from a reflective material, an optical sensor material, or a combination thereof). In some examples, the exterior coating 500 is a decorative coating. In other examples, the exterior coating 500 is a non-decorative coating.

[0043] The laser ablation device can be any device suitable for laser ablation. Types of laser 600 include, but are not limited to, carbon dioxide (CO2) lasers, helium-neon lasers, argon lasers, krypton lasers, xenon lasers, nitrogen lasers, carbon monoxide (CO2) lasers, and excimer lasers. The laser can operate at various pulse lengths (e.g., in the ns, ps, or fs ranges) or as a continuous laser. The wavelength of the laser can be selected depending on the reflective material or optical sensor material, or the reflective material or optical sensor material can be tuned to a predetermined wavelength. For example, the UV-Vis-IR absorption or reflectance of the sensor can be used to determine an appropriate laser-sensor combination. The laser can also be selected from near-infrared (1064 nm) lasers, CO2 (10600 nm) lasers, green (532 nm) lasers, ultraviolet (355 nm) lasers, and plasma lasers.

[0044] Examples of reflective or optical sensor materials include metal or ceramic flakes. Specific metal or ceramic flakes may include one or more of alumina flakes, stainless steel flakes, nickel flakes, and rare earth pigments. The amount of reflective or optical sensor material may depend on the size, weight, and geometry of the flakes, as well as the desired effectiveness and performance of the material.

[0045] In certain approaches, the protective coating layer 300 comprises a reflective material. In other approaches, the protective coating layer 300 comprises an optical sensor material. In certain approaches, the laser sensitive layer 311 (which may be one of a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties) exhibits (i) a color change, (ii) a change in fluorescence, or (iii) light reflection when exposed to the laser 600 or laser beam.

[0046] The (i) color change, (ii) fluorescence, and (iii) light reflection of the optical sensor layer can be monitored by a sensor in a feedback loop to notify a user that the exterior coating is being removed. In a particular example, the method comprises applying a laser 600 to a portion of the exterior coating to remove that portion, and then applying the laser 600 to an additional portion of the exterior coating to remove that additional portion. The additional portion can be exposed to the laser 600 until the desired portion of the exterior coating is removed.

[0047] In one or more examples, ultrasonic waves or stress waves can be formed within the composite structure in response to the laser beam impinging on the surface. The ultrasonic waves can be detected using a detection system and a detection laser beam. In some examples, when the detection laser beam impinges on the ultrasonic waves, the detection laser beam can be altered. Such alterations can include, but are not limited to, changes in path, intensity, phase, frequency, or other characteristics of the detection laser beam, such as, but not limited to, changes in laser intensity, polarization state, bandwidth, and laser phase behavior. Such alterations can be detected by the detection system. The detection system can be configured to detect a signal from one or more detection points on the coated non-metallic composite part 100, the signal corresponding to the altered detection laser beam at a given location. In one illustrative example, the detection system takes the form of an interferometric detection system.

[0048] When the exterior coating 500 comes into contact with the laser beam, the exposure ablates the exterior coating 500. This is why this technique is referred to as laser ablation. Exterior coating materials and removal processes used in the aerospace industry are described in "Aerospace Engineering, vol. 1, pp. 111-114, 2003." For the purposes of this disclosure, laser ablation is defined as the process of removing the exterior coating 500 by irradiating it with a laser beam. Depending on the intensity of the laser 600, the exterior coating 500 may be heated by the absorbed laser energy, evaporating or sublimating, or even converting to plasma. The amount of energy required during laser ablation to remove the exterior coating is material-dependent. The amount of energy should be sufficient to exceed the ablation threshold for pulsed lasers, but can be significantly lower for continuous wave systems, which remove material through a thermal oxidation process. The amount of energy required may vary depending on factors such as the thickness of the exterior coating and the material used to form the exterior coating.

[0049] During exposure to the laser beam, the protective reflective material prevents the laser beam from reaching the non-metallic composite part 200. In some instances, the co-cured layer 312 or the laser-sensitive co-cured layer 320 remains intact. In other instances, depending on the thickness and materials used for the co-cured layer 312 or the laser-sensitive co-cured layer 320, at least a portion of the co-cured layer 312 or the laser-sensitive co-cured layer 320 is removed without reaching the non-metallic composite part 200.

[0050] The method may include placing a protective laser-sensitive layer 311 on top of the co-cured layer 312, which resides on top of the non-metallic composite part 200 prior to curing, such as in an autoclave. Alternatively, reflective or optical materials can be combined with the co-cured layer by including laser-reflective pigments or metal flakes in the co-cured coating formulation. The density and / or surface energy of the coating can be selected or adjusted to cause the pigments or metal flakes to migrate to the layer surface. For example, the density of the coating can be selected or adjusted to be higher than the pigments or metal flakes, causing the pigments or metal flakes to migrate to the surface. In another example, a surface treatment can be used to make the pigments or metal flakes incompatible with the coating matrix, resulting in stratification, causing the pigments or metal flakes to migrate to the surface of the layer.

[0051] As the laser 600 ablates the exterior coating 500, a protective reflective coating or film reflects the laser light to prevent interaction of the laser 600 with the underlying non-metallic composite part. In one or more examples, the reflective coating or film may be tuned to the laser wavelength to reflect that wavelength away from the composite part surface. The protective optical sensor coating is coupled with a feedback loop with the camera 700 to measure the surface in situ to determine when laser ablation of the exterior coating 500 is complete and to prevent interaction of the laser 600 with the underlying coating material. As the laser 600 completes ablation of the exterior coating 500, the underlying optical sensor coating changes color or fluorescence, and the change is captured by a sensor, such as the camera 700, or other sensor device. Other sensor devices include, but are not limited to, complementary metal-oxide semiconductor (CMOS), charge-coupled device (CCD), and infrared indium gallium arsenide (InGaAs) detectors.

[0052] The monitoring step can include determining when the exterior coating 500 has been removed from the composite device by monitoring a feedback loop that can be used to control the ablation system, for example, to direct the laser beam to a new location where the exterior coating 500 is still present.

[0053] In one or more examples, once the exterior coating 500 is removed, repairs can be made to either the laser-sensitive layer 311 or the laser-sensitive co-cure layer 320. Optionally, these layers can be removed and replaced before applying a new exterior coating.

[0054] 1A-1E show example cross-sectional views of coated non-metallic composite parts 100. FIG. 1A shows a coated non-metallic composite part 100 with a protective coating layer 300 applied to the non-metallic composite part 200. In the coated non-metallic composite part 100 shown in FIG. 1B, the protective coating layer 300 is a multi-layer 310 applied to the surface of the non-metallic composite part. In the coated non-metallic composite part 100 shown in FIG. 1C, the multi-layer 310 includes at least one co-cured layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of the co-cured layer 312. The laser-sensitive layer 311 can be a reflective layer, an optical sensor layer, or a layer having both reflective and optical sensor properties. In the coated non-metallic composite part 100 shown in FIG. 1D, the protective coating layer 300 is a co-cured coating with a laser-sensitive material 320a contained therein to form a laser-sensitive co-cured layer 320 applied to the surface of the non-metallic composite part 200. In the coated non-metallic composite part 100 shown in FIG. 1E, a base film 400 is applied to the surface of the non-metallic composite part 200 and a protective coating layer 300 is applied to the base film 400 .

[0055] 2 shows an example of application of an exterior coating 500 as the exterior layer of a coated non-metallic composite part 100 having a protective coating layer 300 comprising multiple layers 310 having at least one co-cured layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of the co-cured layer 312, where the laser-sensitive layer 311 is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties. The exterior coating 500 is then ablated using a laser beam. Once the exterior coating 500 is removed, a new exterior coating is applied.

[0056] 3 shows an example of the application of an exterior coating 500 as the outer layer of a coated non-metallic composite part 100 having a protective coating layer 300 comprising a co-curable coating containing a laser-sensitive material 320a applied to the surface of the non-metallic composite part 200. The exterior coating 500 is then ablated using a laser beam.

[0057] FIG. 4 illustrates an example of laser ablation of an exterior coating 500 using a feedback loop to monitor ablation. The coated non-metallic composite part 100 includes a protective coating layer 300 comprising multiple layers 310 having at least one co-cured layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of the co-cured layer 312. While the illustration uses a camera 700 to monitor ablation, other sensors may also detect the laser-sensitive layer 311. The laser-sensitive layer 311 may be one of a reflective layer, an optical sensor layer, or a layer that is both reflective and optically sensitive. Once the exterior coating 500 is removed, a new exterior coating may be applied.

[0058] 5 illustrates an example of laser ablation of an exterior surface coating 500 using a feedback loop to monitor ablation. A coated non-metallic composite part 100 includes a co-curable coating containing a laser-sensitive material 320a that is applied to the surface of the non-metallic composite part 200. While the illustration uses a camera 700 to monitor ablation, other sensors for detecting the laser-sensitive material 320a are also available. Once the exterior surface coating 500 is removed, a new exterior surface coating can be applied.

[0059] 6 is a schematic diagram of one example of a method 800 for protecting the surface of a non-metallic composite part 200 during laser ablation removal of an exterior coating 500. As shown, method 800 may begin at process block 810 with forming a coated non-metallic composite part 100 by applying a protective coating layer 300 to the surface of the non-metallic composite part 200. Protective coating layer 300 comprises either (a) a multilayer 310 having at least one co-cure layer 312 applied to the surface of the non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of co-cure layer 312 (laser-sensitive layer 311 selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating comprising a laser-sensitive material 320a (laser-sensitive material 320a selected from a reflective material, an optical sensor material, and combinations thereof) contained therein to form a laser-sensitive co-cure layer 320 applied to the surface of the non-metallic composite part 200. The method then proceeds to process block 820 with curing the coated non-metallic composite part 100. After curing of the coated non-metallic composite part 100 is complete, the method 800 may be complete or terminated.

[0060] 7 is a schematic diagram of one example method 900 for removing an exterior coating 500 from a coated non-metallic composite part 100. As shown, method 900 may begin at process block 910, forming a coated non-metallic composite part 100, by applying a protective coating layer 300 to the surface of a non-metallic composite part 200. Protective coating layer 300 comprises either (a) a multi-layer 310 having at least one co-cure layer 312 applied to the surface of non-metallic composite part 200 and at least one laser-sensitive layer 311 applied to the surface of co-cure layer 312 (laser-sensitive layer 311 selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties), or (b) a co-cure coating comprising a laser-sensitive material 320a (laser-sensitive material 320a selected from a reflective material, an optical sensor material, and combinations thereof) contained therein to form a laser-sensitive co-cure layer 320 applied to the surface of non-metallic composite part 200. The method then proceeds to process block 920 with applying an exterior coating to protective coating layer 300. The method then proceeds to process block 930, which includes exposing coated non-metallic composite part 100 to laser 600 to remove exterior coating 500. After removal of exterior coating 500, method 900 may be complete or terminated.

[0061] An exemplary method for forming a coated non-metallic composite part 100 for use on an aircraft or other surface may be described where protective coating layer 300 is a layer comprising a co-curable coating comprising a laser-sensitive material 320a (e.g., a reflective material) contained therein to form a reflective, laser-sensitive co-cured layer 320 applied to the surface of non-metallic composite part 200, and comprises applying exterior coating 500, removing the exterior coating by laser ablation, and then applying a new exterior coating. In one example, the method begins with a buildup of non-metallic composite part 200, applies protective coating layer 300 by applying a co-curable coating comprising a reflective material contained therein to form a reflective co-cured layer, and curing the coated non-metallic composite part 100.

[0062] The surface of the coated non-metallic composite part 100 is surface finished and an exterior coating 500 is applied to the finished surface of the coated non-metallic composite part 100 .

[0063] As the aircraft ages in service, the exterior coating 500 wears away from exposure during service. Using laser ablation, the surface of the coated non-metallic composite part 100 is exposed to a laser beam and emitted light to remove the exterior coating 500. A new exterior coating can then be applied.

[0064] Also disclosed is an exemplary method for forming a coated non-metallic composite part 100 for use on an aircraft or other surface, where the protective coating layer 300 is a multi-layer 310 having at least one co-cured layer 312 applied to the surface of a base film 400 that has been applied to the surface of the non-metallic composite part 200, and at least one laser-sensitive layer 311 that is a reflective layer applied to the surface of the co-cured layer 312, and the method comprises applying an exterior coating 500, removing the exterior coating by laser ablation, and then applying a new exterior coating. The method begins with the buildup of the non-metallic composite part 200, applying the base film 400, applying the protective coating layer 300, which comprises applying the co-cured layer 312 and the laser-sensitive layer 311 that is a reflective layer, and curing the coated non-metallic composite part 100.

[0065] The surface of the coated non-metallic composite part 100 is surface finished and an exterior coating 500 is applied to the finished surface of the coated non-metallic composite part 100 .

[0066] As the aircraft ages in service, the exterior coating 500 wears away from exposure during service. Using laser ablation, the surface of the coated non-metallic composite part 100 is exposed to a laser beam and emitted light to remove the exterior coating 500. A new exterior coating can then be applied.

[0067] Another exemplary method may be described for forming a coated non-metallic composite part 100 for use on an aircraft or other surface, where protective coating layer 300 is a layer comprising a co-curable coating comprising a laser-sensitive material 320a contained therein to form a laser-sensitive co-cure layer 320 applied to the surface of non-metallic composite part 200, where laser-sensitive material 320a is an optical sensor material, and comprises applying an exterior coating 500, removing the exterior coating by laser ablation, and then applying a new exterior coating. In one example, the method may begin with laying up of non-metallic composite part 200 and comprises applying protective coating layer 300 and curing the coated non-metallic composite part 100.

[0068] The surface of the coated non-metallic composite part 100 is surface finished and an exterior coating 500 is applied to the finished surface of the coated non-metallic composite part 100 .

[0069] As the aircraft ages in service, the exterior coating 500 wears away from exposure during service. Using laser ablation, the surface of the coated non-metallic composite part 100 is exposed to a laser beam and emitted light to remove the exterior coating 500. The method may proceed with monitoring to determine when the exterior coating has been removed and the wavelength of the emitted light. A new exterior coating may then be applied.

[0070] Also disclosed is a method for forming a coated non-metallic composite part 100 for use on an aircraft or other surface, where the protective coating layer 300 is a multi-layer 310 comprising at least one co-cure layer 312 applied to the surface of a base film 400 applied to the non-metallic composite part 200 and a laser-sensitive layer 311, which is an optical sensor layer, applied to the surface of the co-cure layer 312, and comprises applying an exterior coating 500, removing the exterior coating by laser ablation, and then applying a new exterior coating. In one example, the method may begin with the buildup of the non-metallic composite part 200 and comprises applying the base film 400, applying the protective coating layer 300, which comprises applying the co-cure layer 312 and applying the laser-sensitive layer, which is an optical sensor layer, and curing the coated non-metallic composite part 100.

[0071] The surface of the coated non-metallic composite part 100 is surface finished and an exterior coating 500 is applied to the finished surface of the coated non-metallic composite part 100 .

[0072] As the aircraft ages in service, the exterior coating 500 wears away from exposure during service. Using laser ablation, the surface of the coated non-metallic composite part 100 is exposed to a laser beam and emitted light to remove the exterior coating 500. The method may proceed with monitoring to determine when the exterior coating 500 has been removed and monitoring the wavelength of the emitted light. A new exterior coating may then be applied.

[0073] The disclosed methods and coatings can be used to remove exterior coatings and to remove exterior coatings from the surfaces of airplanes and similar aircraft, and can also be used on other vehicles, such as, but not limited to, automobiles, land vehicles, and spacecraft.

[0074] Furthermore, the present disclosure includes additional examples detailed in the following sections.

[0075] Item 1 1. A method for protecting a surface of a non-metallic composite part during laser ablation removal of an exterior surface coating, comprising: applying a protective coating layer to a surface of the non-metallic composite part to form a coated non-metallic composite part; and curing the coated non-metallic composite part; The protective coating layer is (a) a multilayer structure having at least one co-cured layer applied to a surface of a non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, wherein the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties; or (b) A method comprising: a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to a surface of a non-metallic composite part; the laser-sensitive material being selected from a reflective material, an optical sensor material, and combinations thereof.

[0076] Section 2 Item 10. The method of claim 1, wherein applying the protective coating layer comprises applying at least one co-cured layer to a surface of the non-metallic composite part and applying a laser-sensitive layer to a surface of the co-cured layer.

[0077] Section 3 Item 10. The method of item 1, wherein applying the protective coating layer comprises applying a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-curable layer applied to the surface of the non-metallic composite part.

[0078] Section 4 Item 3. The method of item 3, wherein the laser-sensitive co-cured layer has a surface adjacent to the non-metallic composite part and an opposite surface of the non-metallic composite part, and the laser-sensitive material is concentrated near the opposite surface of the non-metallic composite part.

[0079] Section 5 5. The method of any one of paragraphs 1 to 4, further comprising using a laser to remove at least a portion of an exterior coating applied to a protective coating layer of the coated non-metallic composite part.

[0080] Section 6 Item 6. The method of any one of items 1 to 5, wherein the non-metallic composite part comprises a carbon reinforced polymer, a glass fiber reinforced polymer, or a mixture thereof, and the co-cured layer comprises a polyurea, a fluorourethane, a polyester, an acrylic, a polycarbonate, a polysilazane, a sol-gel coating, or an epoxy.

[0081] Section 7 7. The method of any one of paragraphs 1 to 6, further comprising applying a primer film to the surface of the non-metallic composite part before applying the protective coating layer.

[0082] Item 8 Item 1. The method according to item 1, wherein the protective coating layer comprises multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is a reflective layer.

[0083] Section 9 Item 10. The method of item 1, wherein the protective coating layer comprises a curable coating and the laser-sensitive material contained therein is a reflective material.

[0084] Section 10 Item 1. The method according to item 1, wherein the protective coating layer comprises multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is an optical sensor layer.

[0085] Section 11 Item 10. The method of item 1, wherein the protective coating layer comprises a curable coating and the laser-sensitive material contained therein is an optical sensor material.

[0086] Item 12 1. A method for removing an exterior coating from a coated non-metallic composite part, comprising: applying a protective coating layer to a surface of the non-metallic composite part; applying an outer coating to the protective coating layer; exposing the coated non-metallic composite part to a laser to remove the exterior coating; The protective coating layer is (a) a multilayer structure having at least one co-cured layer applied to a surface of a non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, wherein the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties; or (b) A method comprising: a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to a surface of a non-metallic composite part; the laser-sensitive material being selected from a reflective material, an optical sensor material, and combinations thereof.

[0087] Item 13 Item 13. The method of item 12, wherein exposing to a laser comprises applying a laser to a portion of the exterior coating to remove that portion, and then applying a laser to an additional portion of the exterior coating to remove the additional portion.

[0088] Section 14 Item 14. The method of item 12 or 13, wherein upon exposure to a laser, the laser-sensitive layer exhibits one or more of a color change, a fluorescence change, and light reflection.

[0089] Section 15 15. The method of any one of clauses 12 to 14, further comprising monitoring one or more of a change in color, a change in fluorescence, and a reflection of light in a feedback loop to indicate removal of the outer surface coating.

[0090] Item 16 Item 16. The method of any one of items 12 to 15, wherein the protective coating layer comprises at least one co-cured layer applied to the surface of the non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, and the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties.

[0091] Item 17 16. The method of any one of paragraphs 12 to 15, wherein the protective coating layer comprises a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to the surface of the non-metallic composite part, the laser-sensitive material being selected from a reflective material, an optical sensor material, and combinations thereof.

[0092] Section 18 Item 13. The method of item 12, wherein the laser-sensitive co-cured layer has a surface adjacent to the non-metallic composite part and an opposite surface of the non-metallic composite part, and the laser-sensitive material is concentrated near the opposite surface of the non-metallic composite part.

[0093] Section 19 Item 13. The method according to item 12, wherein the protective coating layer comprises multiple layers, and the laser-sensitive layer applied on the surface of the co-cured layer is a reflective layer.

[0094] Section 20 Item 13. The method of item 12, wherein the protective coating layer comprises a curable coating and the laser-sensitive material contained therein is a reflective material.

[0095] Section 21 Item 13. The method according to item 12, wherein the protective coating layer comprises multiple layers, and the laser-sensitive layer applied on the surface of the co-cured layer is an optical sensor layer.

[0096] Section 22 Item 13. The method of item 12, wherein the protective coating layer comprises a curable coating and the laser sensitive material contained therein is an optical sensor material.

[0097] Section 23 a protective coating layer applied to the non-metallic composite part; an exterior coating applied to the protective coating layer; The protective coating layer is (a) a multilayer structure having at least one co-cured layer applied to a surface of a non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, wherein the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties; or (b) A coated non-metallic composite part comprising a co-curable coating having a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to a surface of the non-metallic composite part, the laser-sensitive material being selected from a reflective material, an optical sensor material, and combinations thereof.

[0098] Section 24 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer comprises at least one co-cured layer applied to the surface of the non-metallic composite part and at least one laser-sensitive layer applied to the surface of the co-cured layer, and the laser-sensitive layer is selected from a reflective layer, an optical sensor layer, and a layer having both reflective and optical sensor properties.

[0099] Section 25 Item 24. The coated non-metallic composite part of item 23, wherein the protective coating layer comprises a co-curable coating comprising a laser-sensitive material contained therein to form a laser-sensitive co-cured layer applied to the surface of the non-metallic composite part, and the laser-sensitive material is selected from a reflective material, an optical sensor material, and combinations thereof.

[0100] Section 26 Item 26. A coated non-metallic composite part according to item 25, wherein the laser-sensitive co-cure layer has a surface adjacent to the non-metallic composite part and an opposite surface of the non-metallic composite part, and the laser-sensitive material is concentrated near the opposite surface of the non-metallic composite part.

[0101] Section 27 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer has multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is a reflective layer.

[0102] Section 28 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer comprises a curable coating and the laser-sensitive material contained therein is a reflective material.

[0103] Section 29 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer has multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is an optical sensor layer.

[0104] Item 30 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer comprises a curable coating and the laser sensitive material contained therein is an optical sensor material.

[0105] Item 31 Item 31. The coated nonmetallic composite part according to any one of items 23 to 30, wherein the undercoat film or undercoat layer is located between the nonmetallic composite part and either (i) the cured layer or (ii) the laser-sensitive cured layer (a reflective cured layer, an optical sensor cured layer, or a cured layer having both reflectivity and optical sensor properties).

[0106] Section 32 Item 32. The coated non-metallic composite part according to any one of items 23 to 31, wherein the outer surface coating is applied to either (i) at least one laser-sensitive layer or (ii) a laser-sensitive co-cured layer (a reflective co-cured layer, an optical sensor co-cured layer, or a co-cured layer having both reflective and optical sensor properties).

[0107] Item 33 Item 33. The coated non-metallic composite part of any one of items 23 to 32, wherein the protective coating layer comprises a reflective material.

[0108] Section 34 34. The coated non-metallic composite part of paragraph 33, wherein the reflective material comprises metal or ceramic flakes.

[0109] Item 35 Item 35. The coated non-metallic composite part according to item 34, wherein the metal or ceramic piece comprises one or more of an alumina piece, a stainless steel piece, and a nickel piece.

[0110] Section 36 33. The coated non-metallic composite part of any one of paragraphs 23 to 32, wherein the protective coating layer comprises an optical sensor material.

[0111] Section 37 Item 13. The method according to item 1 or 12, wherein the protective coating layer has multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is a layer having both reflective and optical sensor properties.

[0112] Section 38 Item 13. The method according to item 1 or 12, wherein the protective coating layer comprises a curable coating, and the laser-sensitive material contained therein is either a single material having both reflective and optical sensor properties, or at least two different materials, at least one of which is a reflective material and at least one of which is an optical sensor material.

[0113] Section 39 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer has multiple layers, and the laser-sensitive layer applied to the surface of the co-cured layer is a layer having both reflectivity and optical sensor properties.

[0114] Section 40 Item 24. The coated non-metallic composite part according to item 23, wherein the protective coating layer comprises a curable coating, and the laser-sensitive material contained therein is a single material having both reflectivity and optical sensor properties, or at least two different materials, at least one of which is a reflector material and at least one of which is an optical sensor material.

[0115] Section 41 Item 33. The coated non-metallic composite part according to any one of items 23 to 32, wherein the protective coating layer comprises a single material having both reflective and optical sensor properties, or at least two different materials, at least one of which is a reflective material and at least one of which is an optical sensor material.

[0116] Those skilled in the art will appreciate from the foregoing description that the broad techniques of the examples of the present disclosure can be embodied in a variety of forms. Accordingly, while examples of the present invention have been described with reference to specific examples, the true scope of the present invention is not limited to such examples, and other variations will become apparent to those skilled in the art upon review of the drawings, specification, and appended claims. [Explanation of symbols]

[0117] 100 Coated non-metallic composite parts 200 Non-metallic composite parts 300 protective coating layers 310 multilayer 311 Laser sensitive layer 312 Cocure Layer 320 Laser sensitive co-cured layer 400 Base film, base layer 500 outer coating

Claims

1. 1. A method for protecting a surface of a non-metallic composite part (200) during laser ablation removal of an exterior coating (500), comprising: applying a protective coating layer (300) to the surface of the non-metallic composite part (200) to form a coated non-metallic composite part (100); and curing the coated non-metallic composite part (100). the protective coating layer (300) comprises a co-curable coating comprising a laser-sensitive material (320a) contained therein to form a laser-sensitive co-cured layer (320) applied to the surface of the non-metallic composite part (200), the laser-sensitive material (320a) being selected from a reflective material, an optical sensor material, and combinations thereof; The method, wherein the laser-sensitive co-cured layer (320) has a surface adjacent to the non-metallic composite part (200) and an opposite surface of the non-metallic composite part (200), and the laser-sensitive material (320a) is concentrated near the opposite surface of the non-metallic composite part (200).

2. The method described in claim 1, wherein the laser-sensitive material (320a) contained in the co-curable coating is a reflective material.

3. A method according to claim 1 or 2, wherein the laser-sensitive material (320a) contained in the co-curable coating is an optical sensor material.

4. A method for removing an exterior coating (500) from a coated non-metallic composite part (100), comprising: applying a protective coating layer (300) to a surface of the non-metallic composite part (200); applying an outer coating (500) to said protective coating layer (300); exposing the coated non-metallic composite part (100) to a laser (600) to remove the exterior coating (500); the protective coating layer (300) comprises a co-curable coating comprising a laser-sensitive material (320a) contained therein to form a laser-sensitive co-cured layer (320) applied to the surface of the non-metallic composite part (200), the laser-sensitive material (320a) being selected from a reflective material, an optical sensor material, and combinations thereof; The method, wherein the laser-sensitive co-cured layer (320) has a surface adjacent to the non-metallic composite part (200) and an opposite surface of the non-metallic composite part (200), and the laser-sensitive material (320a) is concentrated near the opposite surface of the non-metallic composite part (200).

5. 5. The method of claim 4, wherein exposing to the laser comprises applying the laser to a portion of the exterior coating to remove the portion, and then applying the laser to an additional portion of the exterior coating to remove the additional portion.

6. A method as described in claim 4 or 5, wherein the laser sensitive material (320a) is selected from a reflective material, an optical sensor material, and a combination thereof.

7. A method described in any one of claims 1 to 6, wherein the laser-sensitive material (320a) is a material that has both reflective and optical sensor properties, or at least two different materials, at least one of which is a reflective material and at least one of which is an optical sensor material.

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