Stretchable multilayer film, its manufacturing method, its use, and articles using the same

Abstract

To provide a multi-layer film useful for covering a surface, methods of producing and using the same, and an article comprising the same.SOLUTION: A multi-layer film of the invention comprises sequential layers as follows: a topcoat layer; a boundary layer; a carrier layer; and an adhesive layer. Inclusion of the boundary layer is, surprisingly, found to provide a highly durable multi-layer film that is unlikely to form defects that would disrupt an integrity of the film even if a strong stretching force is applied when the film is applied to a surface. Advantageously, the boundary layer generally promotes a stretching property of the multi-layer film. Articles comprising the same and methods for forming and using the same are also described herein.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention generally relates to multilayer films useful for covering surfaces, methods for making and using the same. The present invention relates to a method for producing a film, and to an article comprising the film to which the present invention is applied. [Background technology]

[0002] Various paint protection films, various paint film appliques, and other various multi-layer Many of them are based on one or more polyurethane layers. Generally, polyurethane has the following chemical properties: environmental resistance, chemical resistance, having one or more of the following properties: abrasion resistance, scratch resistance, and optical clarity; and They often have other desirable properties.

[0003] To improve the properties of the individual layers (e.g. gloss retention, environmental resistance, etc.), polyurethane Attempts have been made to combine polymer layers with other material layers in the form of multilayer films. In order to impart such enhanced properties, the outer (i.e., topcoat) layer applied to the polyurethane carrier layer. However, additional material layers within the multilayer film For example, in general, multilayer film structures contain The more materials included and the thicker it is, the less flexible the multilayer film becomes. The reduced flexibility makes it difficult for the multilayer film to conform well to contoured surfaces. Not only is it increasingly difficult to adhere the film properly, but the effect of the multilayer film on the film during use is also significant. There is also a risk of premature edge lift. Poor adhesion can potentially lead to delamination of interlayers within such multilayer films. There is a risk of causing this.

[0004] For paint protection applications, several multilayer films are readily available on the market today. For example, Minnesota Mining & Manufacturing Company in St. Paul, Minnesota o. (“3M”) is a polyurethane-based company with its SCOTCHGARD and VENTURESHIELD product lines. The company sells a sheet called "Paint Protection Film" that uses this technology. No. 8636 describes a sheet material having a first major surface, a second major surface, and a small portion of the first major surface. a pressure-sensitive adhesive layer covering at least a portion of the flexible polymer sheet material. The finishing film is manufactured by 3M under the trade name SCOTCHCAL PA It is described as being commercially available as INT PROTECTION FILM PUL 0612 and is also an aliphatic poly 6 mil (mil) containing caprolactone-based thermoplastic urethane elastomer Here, it is described as including a polymer film (1 mil = 25.4 μm). Examples of methods for forming polymer films described include extrusion, calendaring, wet coating, and the like. After the polymer film is formed, water is applied to one side of the polymer film. The other side of the polymer film is coated with an acrylic It is laminated with a pressure sensitive adhesive.

[0005] International Publication No. WO03 / 002680 describes a flexible base material and a backing for the base material. an adhesive layer disposed on a surface of the base material; and a protective layer disposed on the front surface of the base material. The protective layer described in International Publication No. WO03 / 002680 is a hard The base material is a hydrophilic film containing a hydrophilic resin and an inorganic oxide hydrophilic agent. The first polyol is a reaction product of a polyester polyol and a multifunctional isocyanate compound. Preferably, the base material comprises a first polyurethane resin layer. a lower layer and an upper layer disposed between the lower layer and the protective layer, the upper layer adhering to the protective layer; The second polycarbonate polyol is a reaction product of a polycarbonate polyol and a polyfunctional isocyanate compound. The upper layer contains a polyurethane resin that is harder than the first polyurethane resin of the lower layer. It is preferable that the protective layer contains a polyurethane resin, and the film is relatively hard and has good elongation at low temperatures. Even if the upper layer is significantly different from the lower layer of the base material, The adhesiveness between the first polyurethane resin and the protective layer can be effectively increased. The polyester polyol is formed from a diol having caprolactone diol in the main chain. It is possible.

[0006] U.S. Patent No. 8,765,263 discloses a method for manufacturing a film comprising a first layer, a second layer, and a pressure sensitive adhesive (PSA). The first layer is at least a polyester film. Polyurethane based on polyethylene, polyurethane based on polycarbonate, or The second layer may comprise at least one polycaprolactone-based polymer, a combination of both of these polymers, or a mixture of both of these polymers. One major surface of the first layer is coated with a second layer of thermoplastic polyurethane. a PSA layer attached to the opposite major surface of the second layer; Thus, the second layer is sandwiched between the first layer and the PSA layer. Although other methods for forming the second layer have been described, the main method is to use polycaprolactone. The base thermoplastic polyurethane is extruded through a die at high temperature.

[0007] A typical problem in implementing such films is finding a suitable fit for non-planar substrates. For example, if you attach a film to the hood of a car, When attaching, the film should be stretched approximately 10% to reach approximately 110% of its length. To aid in the extensibility of such films, the films are often heated. However, in practice, the amount of stretch in the film is often not consistent throughout the film. For example, a portion of the film may be stretched over an adjacent portion of the substrate. If the film is attached (e.g., glued to a substrate) too close to the In other words, the entire area of ​​the film that is stretched is often stretched. When the material is heated unevenly, the area that is stretched at a lower temperature will be significantly As a result, a portion of the film is stretched by at least about 20% or more. In other areas, the stretching may be much smaller. However, the stretching may be as much as 50% locally. It is not uncommon for this to happen, which is becoming a problem. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 02 / 28636 [Patent Document 2] International Publication No. 03 / 002680 [Patent Document 3] U.S. Patent No. 8,765,263 Summary of the Invention [Problem to be solved by the invention]

[0009] If the film is stretched during application, it will be stretched very much, especially locally. The film's properties are often impaired when the film is partially Defects such as cracks that extend through the film or, more severely, tears that extend through the entire thickness of the film Defects are often found in such films, which can lead to impaired film properties. Workers who introduce such films should always follow the instructions for use. It is not always possible to rely on a strong stretching force over the entire area of ​​the film being introduced. It is not always possible to take precautions to minimize the risk of Therefore, a film that does not lose its properties even when stretched strongly is desired. [Means for solving the problem]

[0010] The multilayer film of the present invention comprises a topcoat layer, a boundary layer, a carrier layer, and an adhesive layer. Surprisingly, the inclusion of the boundary layer allows for a reduction in the amount of heat generated during manufacturing using the film. It has excellent durability and does not form defects even when strong stretching forces are applied to the surface when the film is applied. It has been found that a multilayer film is provided that is less susceptible to cracking. and (c) a method for forming and using a film containing the same. Methods for doing so are also described herein. [Brief explanation of the drawings]

[0011] [Figure 1A]FIG. 1A is a black and white SEM image of a multilayer film according to Example 1 after being stretched 30%. [Figure 1B] FIG. 1B is a black and white SEM image of the multilayer film according to Example 1 after being stretched 60%. [Figure 2A] FIG. 2A is a black and white SEM image of a multilayer film according to Comparative Example C1, prior art, after being stretched 30%. [Figure 2B] FIG. 2B is a black and white SEM image of a multilayer film according to Comparative Example C1, prior art, after being stretched 60%. [Figure 3A] FIG. 3A is a black and white SEM image of a prior art multilayer film according to Comparative Example C2 after being stretched 30%. [Figure 3B] FIG. 3B is a black and white SEM image of a prior art multilayer film according to Comparative Example C2 after being stretched 60%. [Figure 4A] FIG. 4A is a black and white SEM image of a prior art multilayer film according to Comparative Example C3 after being stretched 30%. [Figure 4B] FIG. 4B is a black and white SEM image of a prior art multilayer film according to Comparative Example C3 after being stretched 60%. DETAILED DESCRIPTION OF THE INVENTION

[0012] The multilayer film of the present invention has an outwardly exposed topcoat layer and The adhesive layer is disposed between the carrier layer and the outer exposed adhesive layer. The multilayer film also includes an internal boundary layer. Preferably, the boundary layer is an outer exposed adjacent to, i.e., disposed between, the topcoat layer and the inner carrier layer; .

[0013] The boundary layer and the inner carrier layer can be distinguished based on their relative moduli and thicknesses. The relative modulus of elasticity in the present invention is the relative modulus of secant elasticity of the layers of material. The secant modulus is the value obtained by dividing the stress by the strain when the stress or strain is set to a specific value. For the purposes of this invention, it is understood to be the value obtained by dividing the stress by the strain. When determining the relative modulus, the secant modulus is evaluated for the layer at 10% elongation ( (Also referred to as M10 modulus of elasticity). Obtained from TA Instruments (New Castle, DE). Relative modulus can be determined using the handheld Dynamic Mechanical Analysis (DMA) Q800 In this case, the width is 4 to 8 mm, the thickness is 0.02 to 0.04 mm, and the length is 5 For a ~12mm sample, 18M / min until breakage (i.e., mechanical limit) The relative modulus is determined by evaluating the stress ramp rate in Pa. The modulus is measured according to ISO 52 Also determined by testing in accordance with test methods 7-2 or ASTM D-412. The M10 modulus of elasticity of a single layer can be calculated by dividing the stress at 10% elongation by 0.1. and is calculated by (strain = 10%).

[0014] Generally, the M10 modulus of the boundary layer in the present invention is higher than the M10 modulus of the inner carrier layer. In one embodiment, the M10 modulus of the boundary layer is greater than the M10 modulus of the carrier layer. In a further embodiment, the M10 modulus of the boundary layer is at least about 20% greater than the In yet another embodiment, the carrier layer has a modulus at least about 50% greater than the M10 modulus of the carrier layer. The M10 modulus of the boundary layer is at least about 75% greater than the M10 modulus of the carrier layer. In yet another embodiment, the M10 modulus of the boundary layer is greater than the M10 modulus of the carrier layer. is at least about 100% greater than

[0015] In another embodiment, the M10 modulus of the boundary layer is greater than the M10 modulus of the carrier layer. at least about 20% greater than the M10 modulus of the topcoat layer and at least about 20% greater than the M10 modulus of the topcoat layer 20% larger, and the carrier layer and the topcoat layer sandwich a boundary layer therebetween. In an embodiment, the M10 modulus of the boundary layer is the M10 modulus of the carrier layer and the top coat In yet another embodiment, the M10 modulus of the boundary layer is at least about 50% greater than the M10 modulus of the boundary layer. The M10 elastic modulus of the boundary layer is the M10 elastic modulus of the carrier layer and the M10 elastic modulus of the top coat layer. In yet another embodiment, the M10 elasticity of the boundary layer is at least about 75% greater than the elasticity of the boundary layer. The M10 modulus is less than the M10 modulus of the carrier layer and the M10 modulus of the top coat layer. At least about 100% larger.

[0016] The boundary layers generally improve the extensibility of the multilayer film. In one embodiment, the boundary layers , has a maximum elongation greater than that of the top coat layer. The maximum elongation of the layer is at least about 25% greater than the maximum elongation of the topcoat layer. In another embodiment, the maximum elongation of the boundary layer is less than the maximum elongation of the topcoat layer. In yet another embodiment, the maximum elongation of the boundary layer is about 50% greater than the maximum elongation of the topcoat layer. at least about 100% greater than the maximum elongation of

[0017] The inclusion of relatively high modulus boundary layers (compared to the modulus of the carrier layer) in the multilayer film To counteract the increase in overall stiffness of the multilayer film due to the addition of It is commonly used in many multilayer films consisting of a topcoat layer, a carrier layer, and an adhesive layer. It has been found to be beneficial to use a carrier layer with a lower modulus than would be possible with a conventional carrier layer. In one embodiment, the carrier layer has an M10 modulus of elasticity of less than about 20 MPa at 25°C. In one embodiment, the carrier layer has an M10 modulus of less than about 15 MPa at 25° C. .

[0018] The secant modulus of elasticity is the value for one layer when the elongation rate is 100% (also called the M100 modulus of elasticity). In this case, the M100 modulus of the layer is calculated as the elongation rate of 100%. In one embodiment, the M100 modulus of the carrier layer is In another embodiment, the M100 modulus of the carrier layer is less than about 5 MPa. °C and is less than about 4 MPa.

[0019] In one embodiment, the modulus of the boundary layer is measured when a similar test is performed on the carrier layer. The behavior of the carrier layer elastic modulus increases at a slower rate with increasing temperature compared to the behavior of the carrier layer elastic modulus at In another embodiment, the modulus of the boundary layer is reduced by a similar amount in the topcoat layer. The behavior of the topcoat layer modulus as the temperature increases compared to the behavior of the topcoat layer modulus when tested. In a further embodiment, the modulus of the boundary layer decreases at a slower rate than the modulus of the carrier layer. When similar tests were performed on both the carrier layer and the top coat layer, The modulus of the coating layer decreases at a slower rate with increasing temperature compared to the behavior For example, in one embodiment, the boundary layer M100 modulus at 60°C is 25 In another embodiment, the boundary layer has a modulus of elasticity of at least about 60% of the M100 modulus at 100°C. In this case, the M100 modulus of the boundary layer at 60°C is slightly lower than the M100 modulus of the boundary layer at 25°C. For the purposes of this analysis, TA Instruments (Newcastle, DE) The modulus values ​​were measured using a Dynamic Mechanical Analysis (DMA) Q800 available from (Denver, FL). The width can be determined as 4 to 8 mm and the thickness as 0.02 to 0.04 mm. The test was performed on samples with lengths of 5 to 12 mm, at a frequency of 1 Hz, strain of 0.3%, and temperature. Under tension mode with a temperature rise rate of 3°C / min, the specimen reached its breakage (i.e., mechanical limit). The elastic modulus is evaluated according to the ISO 527-2 or ASTM D-412 test. It can also be determined by testing according to the test method.

[0020] Compared to the inner carrier layer, the boundary layer has a thickness that is less than about 50% of the thickness of the carrier layer. In a preferred embodiment, the thickness of the boundary layer is less than about 20% of the thickness of the carrier layer. is.

[0021] Unexpectedly, the use of such boundary layers in (and within) multilayer films This gives multilayer films excellent stretchability without compromising integrity. Compromising integrity means, for example, that the multilayer film is more easily applied when stretched. The compromised integrity is the acceptance of cracks and fissures. This is evidenced by cracking, tearing, etc. of the multilayer film upon stretching. The carrier layer in this embodiment may be extruded or laminated in situ, as described in more detail below. The polymer may be polymerized in situ, but is preferably polymerized in situ.

[0022] [Carrier layer] As used herein, the term "carrier layer" refers to the outer exposed topcoat layer and the outer The carrier layer is used to refer to a layer disposed between the adhesive layer exposed to the It may also be referred to as a substrate layer or similar design. Generally, the multilayer film of the present invention A carrier layer is referred to as an "intermediate layer" if it comprises multiple layers (i.e., "n" individual layers). However, the carrier layer of the multilayer film of the present invention may be any of the other embodiments of the present invention. As shown in the figure, the carrier layer may be a single film layer. In this case, each of the "n" layers may be of the same chemical nature or may be different from each other. In an exemplary embodiment, the "n" layers They have essentially the same chemical properties.

[0023] In an exemplary embodiment, the carrier layer used in the multilayer film of the present invention is a polyurethane. For simplicity, the term "polyurethane" as used herein refers to a layer that is based on polyurethane. The term refers to urethane (also known as carbamate) linkages, urea linkages, or other Polymers containing these combinations of bonds (i.e., in the case of poly(urethane-urea)) Therefore, the polyurethane-based carrier layer contains at least It contains urea bonds, urea bonds, or a combination thereof. The carrier layer is formed by polymerizing at least 80% of the polymer backbone. The basic structure is a polymer with repeating urethane and / or urea bonds.

[0024] The polyurethane-based carrier layer is made of at least one isocyanate-reactive ( For example, a component containing a hydroxyl functional group such as a polyol and at least one isocyanate. By reacting components containing isocyanate-functional (e.g., polyisocyanate) components For example, polyurethanes can be prepared according to the methods of the present invention. Exemplary polymerizable composition components useful for forming a preferred carrier layer include rice bran, National Patent Application Publication No. 2011-0241261 (“Methods for Polymerizing Films This is described in the paper entitled "In-Situ Using a Radiation Source" The publication is incorporated herein by reference in its entirety. PCT International Publication No. W As described in O2017 / 156507, improvements have been made to conventional protective sheets. Such an in-situ polymerized carrier layer is preferably used in the multilayer film of the present invention. It is used as a carrier layer for the film.

[0025] In an exemplary embodiment, polymerization of the polymerizable composition is achieved by ultraviolet radiation, thermal radiation, and electron beam. The method of the present invention begins with utilizing at least one radiation source selected from the group consisting of: Continuous or batch processing may be utilized. For example, in one embodiment of the present invention, In its form, it utilizes relatively low-energy ultraviolet radiation to create polyurethane-based coatings. Continuous processing, such as web-based polymerization of the carrier layer. As another example, in another embodiment of the present invention, individual groups The material is coated with an ultraviolet-curable composition, which is then irradiated with light to form polyurethane. Batch processing can be used, such as forming a carrier layer on a base. Cut.

[0026] According to a preferred embodiment of the method of the present invention, a polyurethane-based carrier layer is formed. The polymerizable composition used for the polymerization is essentially solvent-free. In addition to the environmental and safety concerns associated with solvent-based processes, In this process, the temperature is usually adjusted to effectively remove excess solvent from the polymerized composition. The polyurethane-based carrier layer is essentially It is preferable that the polyurethane-based composition does not contain unreacted solvent. Preferably, the polymerizable composition from which the carrier layer is formed is essentially solvent-free. I wish.

[0027] Given its recognized beneficial properties, the carrier layer is Any suitable polycaprolactone-based polyurethane may be used. A lactone-based polyurethane can be used for the carrier layer, and this polyurethane The polymers are not limited to those that are polymerized in situ. For example, Schweitzer-Mauduit International, Inc. (Greenfield, Massachusetts) is a registered trademark of ArgoGuard. ArgoGuard® 46510, ArgoGuard® 49510, ArgoGuard® 49510-60DV We supply other polycaprolactone-based polyurethane films under the trade name .

[0028] Any suitable additives may be present in the carrier layer. is selected depending on the intended use, as known to those skilled in the art. The amount of such additives used to achieve this effect can be readily determined.

[0029] According to one embodiment of the present invention, the carrier layer has a thickness of about 5 microns to about 1,250 microns. Each of the "n" film layers has a thickness of at least about 5 microns and at most It can be up to about 50 microns thick, and thicker film layers are more resistant to impacts. It is particularly useful in ballistic applications. To provide greater extensibility, in one embodiment of the present invention, the thickness is about 220 microns or less. In a further aspect of the invention, a carrier layer having a thickness of about 180 For example, the carrier layer may have a thickness of about 120 microns to about 150 microns. The carrier layer may have a thickness of about 180 microns. The overall extensibility of the multilayer film is also improved by using thinner carrier layers. This also reduces the overall cost.

[0030] [Top coat layer] Generally, it is located opposite the adhesive layer and is the major planar side of the multilayer film. The non-adhesive layer disposed on the top surface and exposed to the outside is referred to as the "top coat layer." As the name suggests, the adhesive layer is the outer layer of the multilayer film when the multilayer film is applied to an article. The top coat layer of the multilayer film of the present invention may be any suitable A variety of materials can be used.

[0031] The topcoat layer can be of any suitable chemical nature. The topcoat layer provides environmental resistance, chemical resistance, abrasion resistance, scratch resistance, optical transparency, and and other often desirable properties. According to embodiments, the topcoat layer is non-yellowing and exhibits gloss retention (e.g., about 8 (gloss retention on the order of 0 to about 90 gloss units). In an exemplary embodiment, the topcoat The layer comprises a polyurethane-based material. Many suitable topcoats are commercially available. These include, for example, PPG Aerospace PRC-DeSoto (Sylmar, California) ) under the trade name Desothane™ HS (e.g., Desothane™ HS CA8000) There is a polyurethane coating.

[0032] In one embodiment, if present, the topcoat layer is from about 1 micron to about 28 microns. In further embodiments, the topcoat layer has a thickness of from about 5 microns to about In yet another embodiment, the thickness of the topcoat layer is about 5 microns. In yet another embodiment, the thickness of the topcoat layer is from about 100 microns to about 15 microns. In yet another embodiment, the thickness of the topcoat layer is from 5 microns to about 12 microns. The thickness of the topcoat layer is about 5 microns to about 7 microns. may be substantially varied without departing from the spirit and scope of the present invention.

[0033] To protect the topcoat layer until the multilayer film is applied to the substrate, a polymer A liner (e.g., a transparent polyester liner) is disposed adjacent to the topcoat layer. The liner can be placed facing the topcoat layer. After the multilayer film is applied to the substrate, the liner is temporarily exposed to the outside. Such optional liners generally are used to allow for effective handling of the multilayer film. are removed for

[0034] [Boundary layer] Interposed between the topcoat layer and the carrier layer is the boundary layer of the present invention. Fortunately, the inclusion of boundary layers in multilayer films allows for a smoother application of the film to a surface. It is more resistant to compromising defects that can occur when stretched too hard. As explained in the background of this specification, it has been found that a multilayer film is provided in which the surface Cracks and tears often occur in the film after application, indicating that the integrity of the film has been lost. This is evidence that environmental resistance, chemical resistance, abrasion resistance, scratch resistance, Topcoats are shaped to provide desirable properties in many applications, such as optical clarity. The use of a backcoat layer increases the tendency for the above defects to occur in multilayer films. .

[0035] The boundary layer is made of polymers, and the base polymers are polycarbonate, polypropylene, and polyethylene terephthalate. vinyl difluoride, poly(meth)acrylate (e.g., polyacrylate or polymethacrylate) acrylate), polyurethane, modified (e.g., hybrid) polymers thereof, or It may include combinations thereof. In a preferred embodiment, the boundary layer is a polyurethane Polycarbonate-based polyurethanes useful in the boundary layers of the present invention are For examples of tongues, see U.S. Patent No. 4,476,293. Additives may be present in combination with the base polymer within the boundary layer. The materials will be selected according to the knowledge of one skilled in the art based on the specifics of the intended use.

[0036] The boundary layer is made of a relatively high molecular weight, as is evident from its melting point. can be formed by extrusion according to some embodiments of the present invention, The boundary layer preferably has a molecular weight in a range where extrusion is not practical (i.e., poly(ethylene glycol)). In the case of polyurethanes, the polyurethane is a grade of polyurethane that is suitable for extrusion molding in the art. (Not considered a tan).

[0037] The boundary layer may be any layer that does not prevent the desired properties related to its extensibility from being obtained. In one embodiment, the boundary layer has a thickness of about 1 micron to about 125 microns. and more specifically, having a thickness of from about 3 microns to about 95 microns. In some embodiments, the boundary layer is about 20 microns or less, more specifically about 5 microns. The thickness ranges from about 10 microns to about 15 microns.

[0038] According to one aspect of the present invention, a boundary layer of desired thickness is formed by applying a chemical reaction to the solution or dispersion. Solution and dispersion chemistry is well known to those skilled in the art. The percentage of solids may vary, but in one embodiment, the solution has a solids content of about 10-15%. Alternatively, the dispersion has been found to be useful in forming a boundary layer.

[0039] In one embodiment, the chemistry of the solution or dispersion and the method of the present invention are known to those skilled in the art. Using film coating technology, we prepare polyurethane films suitable for boundary layers. Such films can be prepared by reacting multiple components. Such reactive components may include at least one isocyanate-reactive component. , at least one isocyanate-functional component, and optionally at least one reactive These components are reacted to form an isocyanate-terminated polyurethane. Next, the polyurethane prepolymer is dispersed in a dispersing medium, Optionally, it can be chain extended to form a polyurethane-based dispersion, This can be cast to form a polyurethane film. This is preferred in preparing the boundary layer according to the present invention.

[0040] When polyurethane films are prepared from organic solvents or aqueous systems, the solution or dispersion Once formed, it is easily applied to a substrate and then dried to form a polyurethane film. As known to those skilled in the art, drying can be carried out at room temperature (i.e., about 20°C). The reaction may be carried out at room temperature or at an elevated temperature (e.g., from about 25°C to about 150°C). For example, drying may optionally include the use of forced air or a vacuum. This involves placing the statically coated substrate in a forced air or vacuum oven. Drying may be done in an oven or by heating with forced air or high intensity lamps. For example, when drying coated substrates that are continuously conveyed through a chamber Drying can also be performed under reduced pressure (i.e., under pressure less than ambient pressure). This also includes cases where

[0041] Any suitable isocyanate-reactive component may be used. The reactive component comprises at least one isocyanate-reactive material or mixtures thereof. As understood by those skilled in the art, an isocyanate-reactive material is a material that contains at least one activated water. Those skilled in the art of polyurethane chemistry will recognize that a wide variety of materials can be used with this component. For example, amines, thiols, and polyols are suitable as ion exchangers. It is a lactic acid reactive material.

[0042] However, it is preferred that the isocyanate-reactive material be a hydroxy-functional material. Polyols are the preferred hydroxy-functional materials used in the present invention. When reacted with an isocyanate-functional component such as a polyisocyanate, urethane bonds are formed. to provide.

[0043] Unlike mono-ols, polyols have at least two hydroxy functional groups. The ol was traditionally introduced by a polyol with three or more hydroxy functional groups. This contributes to the formation of relatively high molecular weight polymers without the need for such cross-linking. Examples of polyols useful in the present invention include polyester polyols (e.g., lactone polyols) and alkylene oxides (e.g., ethylene oxide; 1,2-epoxy Cyclopropane; 1,2-epoxybutane; 2,3-epoxybutane; isobutyleneoxy and epichlorohydrin) and their adducts, polyether polyols (e.g., Polyoxyalkylene polyols, for example, polypropylene oxide polyols, polyethylene Polyethylene oxide polyol, polypropylene oxide polyethylene oxide copolymer poly polyoxytetramethylene polyols; polyoxycycloalkylene polyols polythioethers; and their alkylene oxide adducts), polyalkylenes Polyols, polycarbonate polyols, mixtures thereof, and compounds derived therefrom Copolymers include, but are not limited to:

[0044] In one embodiment, polycarbonate-based polyurethanes are preferred. According to the polyurethane chemistry of the company, polyurethane-based films with desired properties can be produced. Therefore, in one preferred embodiment, The polycarbonate-based polymers according to the present invention can be produced using recarbonate diols. Polyols containing three or more hydroxy functional groups are generally called diols. Although less preferred than polyols, certain higher functionality polyols may also be used in the present invention. These high functionality polyols may be used alone as the isocyanate-reactive component. or in combination with other isocyanate-reactive materials. Good too.

[0045] To allow for a wider range of latitude in formation, at least two isocyanates are used. An isocyanate-reactive material (such as a polyol) can be used for the isocyanate-reactive component. However, any suitable isocyanate-reactive component may be used to form the polyurethane. The overall polyurethane chemistry offers a lot of flexibility since it can be

[0046] The isocyanate-reactive component reacts with the isocyanate-functional component during the formation of the polyurethane. The isocyanate-functional component may be one isocyanate-functional material or a combination of these. Polyisocyanates and their derivatives (e.g., urea, biurea, Allophanates, polyisocyanate dimers and trimers, and mixtures thereof Polyisocyanates containing the above-mentioned compounds (hereinafter collectively referred to as "polyisocyanates") are Polyisocyanate is a preferred isocyanate-functional material in the isocyanate-functional component. The cyanate has at least two isocyanate functional groups and preferably has hydroxy functionality. When reacted with a carboxylic acid-reactive component, the carboxylic acid provides a urethane bond. Polyisocyanates useful for preparing polyurethanes include those containing methylisocyanate, ... Any of the aliphatic or aromatic polyisocyanates or combinations thereof commonly used in It's a combination.

[0047] Generally, diisocyanates are the preferred polyisocyanates. The diisocyanates include aromatic diisocyanates, aromatic aliphatic diisocyanates, and aliphatic diisocyanates. esters, alicyclic diisocyanates, and diisocyanates with two isocyanate functional groups at both ends Other compounds (e.g., toluene-2,4-diisocyanate-terminated polypropylene oxide) Examples of suitable urethanes include, but are not limited to, hydroxypolyol diurethanes.

[0048] Examples of preferred diisocyanates include: 2,6-toluene diisocyanate 2,5-toluene diisocyanate; 2,4-toluene diisocyanate; phenyl Diisocyanate; 5-chloro-2,4-toluene diisocyanate; 1-chloromethyl Xylylene diisocyanate;Tetramethyl-2,4-diisocyanatobenzene;Xylylene diisocyanate;Tetramethyl- Silylene diisocyanate; 1,4-diisocyanatobutane; 1,6-diisocyanate Hexane; 1,12-diisocyanatododecane; 2-methyl-1,5-diisocyanatopentane Methylenedicyclohexylene-4,4'-diisocyanate; 3-isocyanato Methyl-3,5,5'-trimethylcyclohexyl isocyanate (isophorone diisocyanate) 2,2,4-trimethylhexyl diisocyanate; cyclohexylene-1 ,4-diisocyanate;Hexamethylene-1,6-diisocyanate;;Tetramethylene Cyclohexane-1,4-diisocyanate; Cyclohexane-1,4-diisocyanate; Naphthalene Diphenylmethane-1,5-diisocyanate; Diphenylmethane-4,4'-diisocyanate; Hexyl 1,4-Benzenediisocyanate;3,3′- Dimethoxy-4,4'-diphenyl diisocyanate; Phenylene diisocyanate; Isopropyl Sophorone diisocyanate; Polymethylene polyphenyl isocyanate; 4,4'-biphenyl Phenylene diisocyanate; 4-Isocyanatocyclohexyl-4'-isocyanatophenyl phenylmethane; and p-isocyanatomethylphenyl isocyanate.

[0049] When preparing a polyurethane dispersion for casting into a polyurethane layer, According to one embodiment, the isocyanate-reactive component and the isocyanate-functional component are optionally Optionally, the emulsion may be reacted with at least one reactive emulsifying compound. The compound has at least one anionic functional group, a cationic functional group, an anionic functional group or contains a group capable of forming a cationic functional group, or a mixture thereof. The substance functions as an internal emulsifier because it contains at least one ionizable group. These compounds are therefore called "reactive emulsifying compounds."

[0050] The reactive emulsifying compound contains an isocyanate-reactive component and a small amount of an isocyanate-functional component. can react with at least one of the hydroxy groups and be incorporated into the polyurethane. The reactive emulsifying compound may contain isocyanate-reactive groups or active hydrogen-reactive groups (e.g., hydroxyl-reactive groups). The isocyanate reactant contains at least one, preferably at least two, of the following groups: Reactive groups and hydroxy-reactive groups include, for example, isocyanate groups, hydroxyl groups, methyl groups, The aryl groups include aryl, arylcapto groups, and amine groups.

[0051] Preferably, the reactive emulsifying compound has at least one anionic functional group, or Contains groups capable of forming ionic functional groups (i.e., anion-forming groups). The groups capable of forming functional groups include isocyanate-reactive components (e.g., polyols) and When reacted with an isocyanate-functional component (e.g., a polyisocyanate), such The reactive emulsifying compound is a group capable of forming a group (i.e., an anion-forming group). Anionic functional groups or anion-forming groups are any groups that contribute to the ionization of the reactive emulsifying compound. Suitable groups include, for example, carboxylate, sulfate, sulfone, Examples include dimethylolpropionic acid, ... (DMPA) is a useful reactive emulsifying compound. In addition, 2,2-dimethylbutyric acid, Dihydroxymaleic acid and sulfopolyester diols are other useful reactive emulsifiers. Those skilled in the art will appreciate that a wide variety of reactive emulsifying compounds can be used to prepare polyurethanes according to the present invention. It will be appreciated that this will be useful in preparing

[0052] One or more chain extenders may also be used in preparing the polyurethanes of the present invention. For example, such chain extenders are conventionally used to prepare polyurethanes. aliphatic polyols, aliphatic polyamines, or aromatic polyamines listed in A combination of these may also be used.

[0053] Illustrative examples of aliphatic polyols useful as chain extenders include: 1,4-butane Diol; Ethylene glycol; 1,6-hexanediol; Glycerin; Trimethylol pentaerythritol; 1,4-cyclohexanedimethanol and phenyl Also, hydroquinone bis(β-hydroxyethyl) ether, tetrahydroquinone tetrachlorohydroquinone-1,4-bis(β-hydroxyethyl) ether, and tetrachlorohydroquinone Diols such as chlorohydroquinone-1,4-bis(β-hydroxyethyl) sulfide Although they contain aromatic rings, for the purposes of this invention, aliphatic polyols are not considered to be aliphatic polyols. It should also be noted that aliphatic diols having 2 to 10 carbon atoms are preferred. In particular, 1,4-butanediol is preferable.

[0054] Illustrative examples of useful polyamines are one or more combinations of the following: p,p'-methyl ethylenedianiline and its alkali metal chlorides, bromides, iodides, nitrites and Complex with nitrate; 4,4'-methylenebis(2-chloroaniline); Dichlorobenzidine ;Piperazine;2-Methylpiperazine;Oxydianiline;Hydrazine;Ethylenediamine Hexamethylenediamine;Xylylenediamine;Bis(p-aminocyclohexyl) Methane; dimethyl ester of 4,4'-methylenedianthranilic acid; p-phenylenedia amine;m-phenylenediamine;4,4'-methylenebis(2-methoxyaniline);4 ,4'-Methylenebis(N-methylaniline);2,4-toluenediamine;2,6- Benzidine; 3,4'-dimethylbenzidine; 3,3'-dimethoxybenzidine Dianisidine; 1,3-propanediol bis(p-aminobenzoic acid); Iso 1,2-Bis(2'-aminophenylthio)ethane;3,5-Diethyl Toluene-2,4-diamine; and 3,5-diethyltoluene-2,6-diamine. Preferred amines for use are: 4,4'-methylenebis(2-chloroaniline); 1,3-propanediol bis(p-aminobenzoate); and p,p′-methylene Dianilines and their alkali metal chlorides, bromides, iodides, nitrites and nitrates Complex with salt.

[0055] Regardless of the chemical nature, it is preferred that the boundary layer be essentially uncrosslinked. Although it is possible to form an appropriate boundary layer using a cross-linking agent, However, the amount of crosslinking agent is generally about 100 parts by weight of the crosslinkable polymer before the crosslinking reaction. The amount of the crosslinking agent is less than about 4 parts by weight, preferably less than about 2 parts by weight. If not used in combination with a polymer capable of forming crosslinks, or If used in a way that minimizes the resulting crosslink density (e.g., base In cases where there are minimal reactive sites on the polymer that serve as the base, the crosslinker In a preferred embodiment, the boundary layer is It is essentially free of crosslinkers and their reaction products, so that chemical analysis , the crosslinker and the reaction product are indistinguishable.

[0056] In an exemplary preferred embodiment, U.S. Pat. No. 6,429,999, which is incorporated herein by reference in its entirety. A polyurethane-based toner described in Patent Publication No. 2008-0286576 A topcoat layer is used as a boundary layer. Such a layer provides improved gloss retention. As an outer (topcoat) layer applied to a carrier layer to provide Unexpectedly, in multilayer films (and The use of such materials as boundary layers (internal layers) can compromise the integrity of the multilayer film. It is easy to achieve excellent stretchability in multilayer films without the need for a top The degree of freedom in forming the coating layer is broadened, and the desired top coating layer can be obtained. The lack of integrity can be attributed to, for example, the failure of multi-layer fillers during stretching. If cracks, fissures, etc. are found in the material, this will be evidence.

[0057] [Adhesive layer] The adhesive layer is located on the major surface of the multilayer film opposite the side where the topcoat layer is located. The adhesive layer according to the present invention may be any suitable adhesive layer. An adhesive may be used, and in a preferred embodiment, the adhesive layer comprises a pressure sensitive adhesive.

[0058] The polymer base of the adhesive layer may be of any suitable chemistry. Although (meth)acrylate-acrylate and methacrylate- However, other suitable chemistries are known to those skilled in the art. For example, these chemicals include synthetic and natural rubber, polybutadiene, and copolymers thereof, polyisoprene or copolymers thereof, and silicone (e.g., polydimethylsiloxane and polymethylphenylsiloxane), respectively. Any suitable additives may be added to the polymer on which the adhesive layer is based. It can exist in combination with

[0059] In particular, in one embodiment of the present invention, 2-ethylhexyl acrylate, vinyl acetate and acrylic acid monomer-based adhesives, known by those skilled in the art. It has been found that adhesives polymerized in this manner are useful. Crosslinking may be achieved using aluminum or melanin crosslinkers.

[0060] In one embodiment, the adhesive layer has a thickness of from about 5 microns to about 150 microns. In a further embodiment, the adhesive layer has a thickness of from about 30 microns to about 100 microns. However, the thickness of the adhesive layer may vary without departing from the spirit and scope of the present invention. It can be substantially changed.

[0061] Similar to using a temporary liner for a topcoat layer, the adhesive layer The adhesive may be protected, for example, by a conventional release liner, until application to the adhesive. Thus, the multilayer film can be stored in a roll or other form until it is applied. It can be easily stored and shipped.

[0062] [Formation of multilayer film] In one embodiment, the multilayer film is made of a polyimide film prior to being consolidated into the final multilayer film. Each individual layer is prepared according to the knowledge known to those skilled in the art. Any suitable method can be used to prepare the polymer.

[0063] To prepare the carrier layer, for example, the film is coated with a separate carrier film (e.g., polyester film) to form a supported carrier layer. The adhesive layer can be formed on the opposite side of the boundary layer. At some point before application to the carrier layer side, the supporting carrier film is removed. do.

[0064] Any suitable method can be used to prepare the adhesive layer. For example, in one embodiment As known to those skilled in the art, a film of desired thickness is deposited on a release film. In one embodiment, the adhesive contained in the release film may be The film can be laminated to the carrier layer after the supporting carrier layer is removed from the carrier layer. do.

[0065] Any suitable method can be used to prepare the topcoat layer. In an embodiment, a topcoat film of desired thickness is applied to the surface of the substrate by a smooth coating, as known to those skilled in the art. It can be cast onto a thin film (e.g., polyester film). In one embodiment, a supported topcoat film is laminated to the boundary layer. Used to form a topcoat film for added protection during transport and storage of The smooth film is kept in the assembly until the sheet is applied to the surface. According to this embodiment, the topcoat layer may be applied to the boundary using any suitable method. According to another embodiment, the topcoat layer can be a conventional According to the method, it is formed by coating directly onto the boundary layer.

[0066] The above process involves first preparing the individual layers and then adhering the layers together to form a multi-layer film. According to another embodiment of the present invention, some layers are The individual layers may also be formed simultaneously by coextrusion. 8,303, U.S. Patent Application Publication No. 2011-0137006, and PCT Publication No. As described in International Patent Application Publication No. WO2017 / 156507, film format. Whatever method is used, the process It may be a continuous process or a batch process.

[0067] [Use of multi-layer film] The multilayer films of the present invention are useful in, for example, indoor applications in the transportation, construction and sporting goods industries. Multilayer films are useful in a range of interior and exterior applications. ) can be advantageously applied to at least a portion of the surface of any article for which protection or decoration is desired. Some such articles are, for example, motorized vehicles and and non-motorized vehicles (e.g., conventional bicycles). The surface to be coated may be, for example, painted or unpainted. If it is coated or not, it may be used as a coating material in film form. (also known as paint film appliqué). It exists primarily on the underlying surface. When a multilayer film is adhered to a surface to protect the existing paint, it is often It is called a material protection film.

[0068] The multilayer film of the present invention can be quickly and easily applied to a surface, according to the knowledge of those skilled in the art. The adhesive layer generally has a peelable layer thereon to expose the adhesive. After removing the liner, it is adhered to the surface to be protected. Before the multilayer film is firmly attached to the surface, it is easier to reposition the multilayer film. If a temporary liner is used, the top coat should be applied after the multilayer film is applied to the surface. The temporary liner adjacent to the topcoat layer is removed to allow the topcoat layer to be removed during use. is exposed to the outside. [Example]

[0069] Illustrative embodiments and applications of the present invention are described by the following non-limiting examples.

[0070] [Scanning electron microscope (SEM) test method] Samples were prepared to evaluate the extensibility-related properties of each exemplified multilayer film. The specimens were then stretched and analyzed under high vacuum using an SEM to detect the presence of cracks, fissures, etc. The presence of fluorescein was determined using a FEI Quanta™ 200 SEM (ThermoFisher Scientific The SEM images were acquired using a microscope (Hillsboro, OR) with HV 30.0 kV, spot 3.0, WD 11.8 mm, magnification 100x, and Det.SSD.

[0071] Four film samples of each exemplified multilayer film were stretched to the desired elongation. , and applied in a stretched state to stainless steel test panels (all performed at room temperature). One of the film samples was stretched by hand by 30% lengthwise, and one film size One film sample was stretched by hand 40% lengthwise, and one film sample was stretched by hand 40% lengthwise. One film sample was stretched by hand in the longitudinal direction by 50% and one film sample was stretched by hand by 60%. A film sample stretched 30% at 100°C will stretch to 130% of its initial length. It should be understood that the same principles apply to the multiple elongation rates shown. do.

[0072] Approximately one hour after applying each film sample to the test panel, the assembly was By placing it in a box oven for 2 hours or 24 hours as shown in The assembly was exposed to a high temperature of approximately 90°C. The assembly was removed from the oven and allowed to cool to room temperature. After cooling, the samples were analyzed using SEM.

[0073] Alternative methods for identifying defects in stretched multilayer films. Surfaces to which multilayer films have been applied for analysis using scanning electron microscope testing methods Instead of removing the multilayer film from the surface, the film was observed under an optical microscope after it had been applied to the surface. or use a magnifying glass to analyze and identify defects, including cracks within the film and tears in the film. Many of these defects may be detected by these alternative methods. This can be confirmed.

[0074] [Example 1] 5.7 mil thick web polymerized (i.e., substantially 11GSM Polycarbonate Polyurethane with a (chemically polymerized) polyurethane carrier layer The boundary layer is then coated with a 5GSM polyurethane top coat. The other side of the polyurethane carrier layer was topcoated with an acrylic pressure-sensitive adhesive. Coated at 1.5 mil thickness.

[0075] The samples were exposed to high temperatures of approximately 90°C for 2 hours before testing. The results of the analysis are summarized in Table 1 and correspond to the amount of elongation. The SEM images of the sample after 60% elongation and after 60% elongation are shown in Figs. 1A and 1B, respectively. It is included in the detailed description.

[0076] [Comparative Example C1] A 6 mil thick web polymerized polyurethane carrier layer is attached to an 11 GSM polyurethane The other side of the polyurethane carrier layer was topcoated with 1. A 5 mil thick coating of acrylic pressure sensitive adhesive was applied.

[0077] The samples were then subjected to high temperatures of approximately 90°C for 2 hours before being examined. The analysis results are shown in Table 1, corresponding to the amount of elongation. SEM images of the layer film after stretching by 30% and 60%, respectively, are shown in Figure 2A. and FIG. 2B. After stretching by 60%, as shown in FIG. 2B, At least four substantially transverse cracks developed.

[0078] [Comparative Example C2] 6 mil thick extruded polyurethane carrier layer (Estane® ALRCL93 AV (extruded material obtained from Lubrizol) versus 11GSM polyester The other side of the polyurethane carrier layer was topcoated with a urethane topcoat. It was coated with a Kryl pressure sensitive adhesive to a thickness of 1.5 mils.

[0079] The samples were exposed to high temperatures of approximately 90°C for 2 hours before testing. The results are shown in Table 1 in correspondence with the amount of elongation. Photographs of the SEM images after 60% stretching and after 60% stretching are included in Figures 3A and 3B, respectively. As shown in Figure 3B, after 60% stretching, at least four specimens were Qualitatively, large cracks extending laterally were formed.

[0080] [Table 1]

[0081] As shown in Table 1, when the elongation amount was 30%, the However, upon further stretching, the film sample of Comparative Example C2 The film sample of Example 1 cracked when stretched by 60%. When stretched by 50% or 60%, the film of Comparative Example C1 The sample cracked.

[0082] [Comparative Example C3] Commercially available coatings from Eastman Chemical Company (Martinsville, VA) A protective film (trade name: SunTek® PPF ULTRA) was analyzed. The samples were tested after being exposed to high temperatures of about 90°C for 2 hours. The SEM images of the film after stretching it by 30% and 60% are shown in the same manner as in the present specification. 4A and 4B. As shown in FIG. 4B, after being stretched by 60%, At least four large cracks extending substantially laterally developed.

[0083] [Example 2] Multilayer films were prepared according to Example 1, except that the samples were heated to approximately 90°C prior to testing. The film was exposed to high temperatures for 24 hours. The results of SEM analysis of the film were compared to the amount of elongation. The correspondence is shown in Table 2.

[0084] [Comparative example C4] Multilayer films were prepared according to Comparative Example C1, except that the samples were allowed to stand for approximately 90 minutes before testing. The film was exposed to high temperatures of 100°C for 24 hours. The results of SEM analysis of the film were analyzed to determine the amount of elongation. The correspondence between these is shown in Table 2.

[0085] [Comparative example C5] Multilayer films were prepared according to Comparative Example C2, except that the samples were cooled to approximately 90°C prior to testing. The film was exposed to high temperatures of 100°C for 24 hours. The results of SEM analysis of the film were analyzed to determine the amount of elongation. The correspondence between these is shown in Table 2.

[0086] [Table 2]

[0087] table 2 As shown in Figure 1, when the stretch amount is 30%, Comparative example C5 The film sample also showed defects. This occurred. Upon further stretching, all of the film samples of Comparative Example C5 cracked. 2The film sample is 50 Even when stretched to 100%, no defects were observed. 40 % ~ When stretched 60%, the film of Comparative Example C4 tore.

[0088] Various modifications and variations to the present invention are contemplated as defined by the appended claims. It will become apparent to those skilled in the art without departing from the spirit and scope of the invention. The steps recited in any method claim are not necessarily recited unless expressly stated otherwise. Note that the steps do not have to be performed in the order listed. In carrying out the present invention, the reader will understand variations from the order in which they are listed. The absence of mention or discussion of a function, step, or component does not necessarily mean that it does not exist. Claims in which an unwanted feature or element is excluded by disclaimer or other claim language Provide evidence.

[0089] Furthermore, as used throughout the specification, numerical ranges refer to all values ​​within the range. It can be used as shorthand for specifying the terminus of a range. ) can be selected as a value. Similarly, any discrete value within the range can be selected as a value. It may be selected as a minimum or maximum value that will be mentioned in the description and claims.

[0090] Furthermore, as discussed herein, it should again be noted that the compositions described herein may contain all components in one or more parts. Furthermore, while the present specification refers to the preparation of various intermediate components (e.g., prepolymers), some of such intermediate components may be commercially available, and therefore, commercially available products can be used in accordance with the present invention instead of preparing the same by other methods. Other variations will be apparent to those skilled in the art. It should also be noted that the molecular weights described herein are number average molecular weights unless otherwise specified. Furthermore, the properties described or measured herein are properties at room temperature and atmospheric pressure unless otherwise specified. The present invention includes the following embodiments. [Aspect 1] a top coat layer; The boundary layer and The carrier layer and an adhesive layer; A multilayer film comprising, as successive layers: [Aspect 2] 10. The multilayer film of embodiment 1, wherein the multilayer film is a polyurethane-based film. Aspect 3 10. The multilayer film of claim 1, wherein the adhesive layer comprises a pressure-sensitive adhesive. Aspect 4 10. The multilayer film of claim 1, further comprising a release film on an outer surface of the adhesive layer. Aspect 5 10. The multilayer film of claim 1, further comprising a carrier film on an outer surface of the topcoat layer. Aspect 6 10. The multilayer film of claim 1, wherein the carrier layer is an in situ polymerized layer. Aspect 7 2. The multilayer film of claim 1, wherein when the film is exposed to a temperature of about 90° C. for 2 hours and stretched 40% in the longitudinal direction of the film, and then observed using SEM testing, the heated and stretched film exhibits no cracks or tears. Aspect 8 10. The multilayer film of claim 1, wherein when the film is exposed to a temperature of about 90° C. for 2 hours and stretched 60% in the longitudinal direction of the film, and then observed using SEM testing, the heated and stretched film exhibits no cracks or tears. Aspect 9 10. The multilayer film of claim 1, wherein when the film is exposed to a temperature of about 90° C. for 24 hours and stretched 40% in the longitudinal direction of the film, the heated and stretched film exhibits no cracks or tears when observed using SEM testing. Aspect 10 10. The multilayer film of claim 1, wherein when the film is exposed to a temperature of about 90° C. for 24 hours and stretched 60% in the longitudinal direction of the film, the heated and stretched film exhibits no cracks or tears when observed using SEM testing. Aspect 11 10. The multilayer film of claim 1, wherein the boundary layer has an M10 modulus that is at least about 20% greater than the M10 modulus of the carrier layer. Aspect 12 12. The multilayer film of claim 11, wherein the boundary layers have an M10 modulus that is at least about 20% greater than the M10 modulus of the topcoat layers that sandwich the boundary layers. Aspect 13 10. The multilayer film of claim 1, wherein the boundary layer has an M10 modulus that is at least about 50% greater than the M10 modulus of the carrier layer. Aspect 14 14. The multilayer film of claim 13, wherein the boundary layers have an M10 modulus that is at least about 50% greater than the M10 modulus of the topcoat layers that sandwich the boundary layers. Aspect 15 10. The multilayer film of claim 1, wherein the boundary layer has an M10 modulus that is at least about 75% greater than the M10 modulus of the carrier layer. Aspect 16 16. The multilayer film of claim 15, wherein the boundary layers have an M10 modulus that is at least about 75% greater than the M10 modulus of the topcoat layers that sandwich the boundary layers. Aspect 17 10. The multilayer film of claim 1, wherein the boundary layer has an M10 modulus that is at least about 100% greater than the M10 modulus of the carrier layer. Aspect 18 18. The multilayer film of claim 17, wherein the M10 modulus of the boundary layers is at least about 100% greater than the M10 modulus of the topcoat layers that sandwich the boundary layers. Aspect 19 10. The multilayer film of claim 1, wherein the boundary layer has a maximum elongation greater than the maximum elongation of the topcoat layer. Aspect 20 10. The multilayer film of claim 1, wherein the maximum elongation of the boundary layer is at least about 25% greater than the maximum elongation of the topcoat layer. Aspect 21 10. The multilayer film of claim 1, wherein the maximum elongation of the boundary layer is at least about 50% greater than the maximum elongation of the topcoat layer. Aspect 22 10. The multilayer film of claim 1, wherein the maximum elongation of the boundary layer is at least about 100% greater than the maximum elongation of the topcoat layer. Aspect 23 10. The multilayer film of claim 1, wherein the carrier layer has an M10 modulus of less than about 20 MPa at 25° C. Aspect 24 10. The multilayer film of claim 1, wherein the carrier layer has an M10 modulus of less than about 15 MPa at 25° C. Aspect 25 10. The multilayer film of claim 1, wherein the carrier layer has an M100 modulus of less than about 5 MPa at 25° C. Aspect 26 10. The multilayer film of claim 1, wherein the carrier layer has an M100 modulus of less than about 4 MPa at 25° C. Aspect 27 2. The multilayer film of embodiment 1, wherein the boundary layer has an M100 modulus at 60°C that is at least about 60% of the boundary layer's M100 modulus at 25°C. Aspect 28 2. The multilayer film of embodiment 1, wherein the boundary layer has an M100 modulus at 60°C that is at least about 70% of the boundary layer's M100 modulus at 25°C. Aspect 29 10. The multilayer film of claim 1, wherein the boundary layer has a thickness that is less than about 50% of the thickness of the carrier layer. Aspect 30 10. The multilayer film of claim 1, wherein the boundary layer has a thickness that is less than about 20% of the thickness of the carrier layer. Aspect 31 An article comprising at least one surface, the article comprising the multilayer film of embodiment 1 over at least a portion of the surface. Aspect 32 32. The article of claim 31, wherein the article comprises a motorized vehicle. Aspect 33 32. The article of claim 31, wherein when the film of the article is observed using SEM examination, no cracks or tears are observed in the multilayer film. Aspect 34 10. A method of using the multilayer film of embodiment 1 to cover a surface of a motorized vehicle, comprising: providing a multilayer film according to aspect 1; applying the multilayer film to the surface of the motorized vehicle. Aspect 35 35. The method of claim 34, wherein the surface is at least partially painted. Aspect 36 35. The method of claim 34, wherein the multilayer film constitutes a coating in the form of a film. Aspect 37 35. The method of claim 34, wherein the multilayer film is heated and stretched to conform to the surface. Aspect 38 35. The method of embodiment 34, wherein the surface is non-planar. Aspect 39 A method according to claim 34, wherein when observed after application of the film to the surface of the motorized vehicle, no cracks are observed as a result of application and no tears occur in the multilayer film. Aspect 40 10. A method of forming the multilayer film of embodiment 1, the method comprising polymerizing the carrier layer in situ.

Claims

1. A topcoat layer comprising polyurethane; a boundary layer comprising polycarbonate, polyvinyl fluoride, poly(meth)acrylate, polyurethane, modified polymers thereof, or combinations thereof; a carrier layer comprising polyurethane; an adhesive layer; as successive layers, A multilayer film, wherein the M10 modulus (measured in accordance with ISO 527-2) of the boundary layers is at least 100% greater than the M10 modulus (measured in accordance with ISO 527-2) of the carrier layer.

2. 10. The multilayer film of claim 1, wherein the M10 modulus (measured in accordance with ISO 527-2) of the boundary layers is at least 20% greater than the M10 modulus (measured in accordance with ISO 527-2) of the topcoat layers sandwiching the boundary layers.

3. A multilayer film as described in claim 1 or claim 2, wherein the M10 modulus of elasticity of the carrier layer (measured in accordance with ISO 527-2) is less than 20 MPa at 25°C.

4. A multilayer film described in any one of claims 1 to 3, wherein the M100 modulus of elasticity of the boundary layer at 60°C (measured in accordance with ISO 527-2) is at least 60% of the M100 modulus of elasticity of the boundary layer at 25°C (measured in accordance with ISO 527-2).

5. A multilayer film as described in any one of claims 1 to 4, wherein the adhesive layer comprises a pressure-sensitive adhesive.

6. A multilayer film as described in any one of claims 1 to 5, further comprising a release film on the outer surface of the adhesive layer.

7. A multilayer film as described in any one of claims 1 to 6, further comprising a carrier film on the outer surface of the top coat layer.

8. A multilayer film as described in any one of claims 1 to 7, wherein the carrier layer is an in-situ polymerized layer.

9. A multilayer film as described in any one of claims 1 to 8, wherein the thickness of the boundary layer is less than 50% of the thickness of the carrier layer.

10. A multilayer film as described in any one of claims 1 to 9, wherein the thickness of the boundary layer is less than 20% of the thickness of the carrier layer.

11. An article comprising at least one surface, the article comprising the multilayer film of any one of claims 1 to 10 on at least a portion of said surface.

12. An article as described in claim 11, wherein the article is a motorized vehicle.

13. An article as described in claim 11 or 12, wherein when the film of the article is observed using an SEM test method, no cracks or tears are observed in the multilayer film.

14. 11. A method of using a multilayer film according to any one of claims 1 to 10 to cover the surface of a motor vehicle, comprising the steps of: A multilayer film according to any one of claims 1 to 10 is prepared, applying the multilayer film to the surface of the motorized vehicle.

15. The method of claim 14, wherein the surface is at least partially painted.

16. A method according to claim 14 or 15, wherein the multilayer film constitutes a coating in the form of a film.

17. A method according to any one of claims 14 to 16, wherein the multilayer film is heated and stretched to conform to the surface.

18. The method of claim 14, wherein the surface is non-planar.

19. A method according to any one of claims 14 to 18, wherein when observed after application of the film to the surface of the motorized vehicle, no cracks are observed as a result of application and no tears occur in the multilayer film.

20. A method for forming a multilayer film according to any one of claims 1 to 10, the method comprising polymerizing the carrier layer in situ.

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