Paint substitute film, laminate, molded product, vehicle exterior part, and method for manufacturing laminate.

Abstract

A paint substitute film comprising, in order, a colored layer, a first adhesive layer, a base film, and a second adhesive layer, wherein: the base film includes an A layer and a B layer; the plane orientation coefficient of the B layer is 0.165-0.180, inclusive; the difference between the melting point TmB of the B layer and the melting point TmA of the A layer is 20-35°C, inclusive; and in both the machine direction and the width direction of the base film, the residual ratio of internal stress (specifically, the residual ratio of internal stress found using │1-(Ub / Ua)│×100) in tensile testing carried out at 100°C is at most 25%.

Description

Technical Field

[0001] The present invention relates to a coating substitute film that covers a resin used for interior and exterior parts of a vehicle such as an automobile with a film instead of coating, and exhibits good adhesion to the resin and excellent appearance design.

Background Art

[0002] Conventionally, in order to improve the design of exterior parts of a vehicle (for example, resin molded products such as fenders, bumpers, bonnets, wheel caps, etc.), spray coating is generally used. However, in recent years, in the coating process including such spray coating, a large amount of equipment and space are required because coating and drying are repeated, and productivity is reduced. Therefore, for the purpose of rationalizing the coating process, etc., a method of improving the appearance of a product by laminating a decorative film (hereinafter referred to as a coating substitute film) on the exterior part has been studied.

[0003] In Patent Document 1, a heat-sealable film has been proposed as a film that is physically adhered to a metal foil or a metal plate. Specifically, by using a polyester B layer with a low surface orientation in the thickness direction, having a surface orientation coefficient of "1.500 or more", and a heat-sealing layer with a thickness of 4 to 40 μm made of a polymer having a number average molecular weight of 15,000 or more and contacting this, delamination within the B layer is suppressed and a decrease in adhesive force is reduced.

[0004] In Patent Document 2, among the two-layer polyester films composed of a B layer and an adhesive layer, the refractive index in the thickness direction of the B layer is less than 1.500, and the melting point difference between the B layer and the adhesive layer is 20 °C or more, so that it has an excellent appearance design required for an outer panel of an automobile or the like and can exhibit good adhesion to a metal.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] When molding resin parts for vehicles, if the adhesion between the resin part and the paint substitute film is insufficient, warping that may occur after molding the resin part may result in defects such as tearing or peeling of the film. The object of the present invention is to provide a paint substitute film that exhibits excellent adhesion to molded resin parts (i.e., resin molded products) and shows excellent appearance and design. [Means for solving the problem]

[0007] As a result of diligent research conducted by the present inventors to achieve the above objectives, they discovered that in a paint substitute film including a base film (specifically, a base film including layers A and B), if the base film exhibits stress-strain curve characteristics similar to those of a resin part, and the surface orientation coefficient of layer B in the base film is above a certain level, the paint substitute film exhibits excellent adhesion to resin parts while also exhibiting excellent moldability. The inventors continued their research and improvements, and have now completed the inventions represented below.

[0008] [1] A paint substitute film comprising a protective film, a surface protective layer, a coloring layer, a first adhesive layer, a base film, and a second adhesive layer in this order, The aforementioned base film is a laminated film comprising at least two layers, an A layer and a B layer. The aforementioned layer A is a layer that mainly contains crystalline polyester as its constituent component, The aforementioned layer B is a layer that mainly contains crystalline polyester as its constituent component. The surface orientation coefficient of the B layer is 0.165 or more and 0.180 or less, the melting point TmB of the B layer is higher than the melting point TmA of the A layer, and the melting point difference TmB-TmA is 25°C or more and 35°C or less. In both the flow direction and the width direction of the aforementioned base film, the 20% elongation stress: F20 value in the tensile test under 100°C conditions is 60 MPa or more and 110 MPa or less. A coating substitute film wherein, in both the flow direction and the width direction of the base film, the residual rate of the internal stress shown in the following formula 1 in a tensile test under 100°C conditions is 25% or less. Equation 1: Percentage of remaining internal stress (%) = |1 - (Ub / Ua)| × 100 Here, the tensile test described above was performed using a sample with a width of 15 mm, with a chuck distance of 50 mm, pulling at a tensile speed of 1000 mm / min until 20% elongation was achieved, and then returning to a chuck distance of 50 mm at a speed of 2000 mm / min after 20% elongation. The above Ua refers to the elastic strain energy from the starting point 0 to the yield point in the stress-strain curve obtained from the above tensile test, and the above Ub refers to the elastic strain energy when the stress-strain curve obtained from the above tensile test is returned to the distance between the chucks from 20% elongation. [2] The paint substitute film according to [1], wherein the surface orientation coefficient of layer A is 0.03 or less than the surface orientation coefficient of layer B. [3] The coating substitute film according to [1] or [2], wherein the sum of the shrinkage rate in the flow direction and the thermal shrinkage rate in the width direction after heat treatment of the laminated film at 150°C for 15 minutes is 1.0% or more and 5.0% or less. [4] The coating substitute film according to any one of [1] to [3], wherein the first adhesive layer comprises a resin having at least one functional group selected from the group consisting of epoxy groups, oxazoline groups, silanol groups, and isocyanate groups. [5] A paint substitute film according to any of [1] to [4], wherein the thickness of the first adhesive layer is 10 nm to 200 nm. [6] The paint substitute film according to any one of [1] to [5], wherein the colored layer contains 0.5% by mass or more and less than 40% by mass of a coloring agent based on 100% by mass of the resin composition constituting the colored layer. [7] The surface protective layer comprises at least one selected from the group consisting of thermosetting resins and photocurable resins as its main component, the paint substitute film according to any one of [1] to [6]. [8] A film-coated resin laminate in which a resin plate is laminated on the second adhesive layer side surface of a paint substitute film described in any of [1] to [7]. [9] A resin component obtained by hot pressing, heat bending, or vacuum forming the film-coated resin laminate described in [8].

[10] A vehicle exterior part using the film-coated resin laminate described in [8].

[0009] The present invention can also be described as having the configuration shown in

[11] below.

[11] A paint substitute film comprising a colored layer, a first adhesive layer, a laminated film, and a second adhesive layer in this order, The laminated film includes layer A and layer B, The aforementioned layer A contains a first crystalline polyester as its main component, The aforementioned layer B contains a second crystalline polyester as its main component, The surface orientation coefficient of the aforementioned B layer is 0.165 or more and 0.180 or less. The melting point of layer B is higher than the melting point of layer A, and the difference between the melting point of layer B and the melting point of layer A is 20°C or more and 35°C or less. When the laminated film was subjected to a tensile test, the residual internal stress index was 25% or less in both the flow direction and the width direction of the laminated film. The aforementioned remaining index rate is expressed by |1-(Ub / Ua)|×100, The aforementioned tensile test was performed by gripping a 15 mm wide test specimen with a pair of chucks at a distance of 50 mm between the chucks, widening the distance between the chucks at a tensile speed of 1000 mm / min at 100°C until a 20% strain occurred, and then returning the distance between the chucks to 50 mm at a speed of 2000 mm / min at 100°C. The aforementioned Ua is a value obtained by integrating the stress-strain curve obtained from the tensile test from 0% strain to yield strain. The aforementioned Ub is a value obtained by integrating the stress-strain curve from 20% strain to the strain at which the stress is 0 MPa. Paint substitute film.

[0010] The present invention preferably further comprises the configurations described in

[12] and later below.

[12] Further comprising a protective film and a surface protective layer, The protective film, the surface protective layer, the coloring layer, the first adhesive layer, the laminated film, and the second adhesive layer are arranged in this order. The paint substitute film described in

[11] .

[13] The laminated film is a coating substitute film according to

[11] or

[12] , wherein the 20% strain tensile stress of the tensile test in both the flow direction and the width direction is 60 MPa or more and 110 MPa or less.

[14] A paint substitute film according to any one of

[11] to

[13] , wherein the surface orientation coefficient of the B layer is greater than the surface orientation coefficient of the A layer, and the difference between the surface orientation coefficient of the B layer and the surface orientation coefficient of the A layer is 0.03 or more.

[15] The laminated film is a coating substitute film according to any one of

[11] to

[14] , wherein when heat-treated at 150°C for 15 minutes, the sum of the thermal shrinkage rate in the flow direction and the thermal shrinkage rate in the width direction is 1.0% or more and 5.0% or less.

[16] The coating substitute film according to any one of

[11] to

[15] , wherein the first adhesive layer comprises a resin having at least one functional group selected from the group consisting of epoxy groups, oxazoline groups, silanol groups, and isocyanate groups.

[17] A paint substitute film according to any of

[11] to

[16] , wherein the thickness of the first adhesive layer is 10 nm to 200 nm.

[18] The paint substitute film according to any one of

[11] to

[17] , wherein the colored layer contains 0.5% by mass or more and less than 40% by mass of a coloring agent based on 100% by mass of the resin composition constituting the colored layer. 〔19〕 The coating replacement film according to any one of 〔12〕 to 〔18〕, wherein the surface protection layer contains at least one of a thermosetting resin and a photocurable resin. 〔20〕 The coating replacement film according to any one of 〔11〕 to 〔19〕, wherein the colored layer, the first adhesive layer, the B layer, the A layer, and the second adhesive layer are arranged in this order. 〔21〕 A resin plate, and the coating replacement film according to any one of 〔11〕 to 〔20〕 laminated on the resin plate, wherein the second adhesive layer is arranged between the resin plate and the laminated film. A laminate. 〔22〕 A molded product obtained by molding the laminate according to 〔21〕. 〔23〕 A molded product obtained by hot press molding, thermoforming, or vacuum molding the laminate according to 〔21〕. 〔24〕 An exterior component of a vehicle including the laminate according to 〔21〕. 〔25〕 A method for manufacturing a laminate, including pressing a resin plate and the coating replacement film according to any one of 〔11〕 to 〔20〕 such that the second adhesive layer of the coating replacement film contacts the resin plate. A method for manufacturing a laminate. 〔26〕 The coating replacement film according to any one of 〔11〕 to 〔20〕, wherein the sum of the heat shrinkage rate in the flow direction and the heat shrinkage rate in the width direction is 4.8% or less. 〔27〕 The coating replacement film according to any one of 〔11〕 to 〔20〕, wherein the sum of the heat shrinkage rate in the flow direction and the heat shrinkage rate in the width direction is 4.5% or less. 〔28〕 The coating replacement film according to any one of 〔11〕 to 〔20〕, wherein the sum of the heat shrinkage rate in the flow direction and the heat shrinkage rate in the width direction is 4.2% or less. 〔29〕 The coating replacement film according to any one of 〔11〕 to 〔20〕, wherein the sum of the heat shrinkage rate in the flow direction and the heat shrinkage rate in the width direction is 4.0% or less.

Advantages of the Invention

[0011] The paint-alternative film of the present invention exhibits excellent adhesion and moldability to various resin parts, i.e., resin components, and can provide resin parts with excellent appearance and design, free from appearance defects due to tearing or peeling of the film after press molding. The paint-alternative film of the present invention can provide the value of eliminating the painting process in the manufacturing of resin parts. [Brief explanation of the drawing]

[0012] [Figure 1] This diagram illustrates the concept of the formula for calculating the residual rate of internal stress. [Modes for carrying out the invention]

[0013] (Paint replacement film) A paint-alternative film according to an embodiment of the present invention comprises, in this order, a colored layer, a first adhesive layer, a laminated film, and a second adhesive layer. The laminated film includes layer A and layer B, The aforementioned layer A contains a first crystalline polyester as its main component, The aforementioned layer B contains a second crystalline polyester as its main component, The surface orientation coefficient of the aforementioned B layer is 0.165 or more and 0.180 or less. The melting point of layer B is higher than the melting point of layer A, and the difference between the melting point of layer B and the melting point of layer A is 20°C or more and 35°C or less. When the laminated film was subjected to a tensile test, the residual internal stress index was 25% or less in both the flow direction and the width direction of the laminated film. The aforementioned remaining index rate is expressed by |1-(Ub / Ua)|×100, The aforementioned tensile test was performed by gripping a 15 mm wide test specimen with a pair of chucks at a distance of 50 mm between the chucks, widening the distance between the chucks at a tensile speed of 1000 mm / min at 100°C until a 20% strain occurred, and then returning the distance between the chucks to 50 mm at a speed of 2000 mm / min at 100°C. The aforementioned Ua is a value obtained by integrating the stress-strain curve obtained from the tensile test from 0% strain to yield strain. The aforementioned Ub is a value obtained by integrating the stress-strain curve from 20% strain to the strain at which the stress is 0 MPa.

[0014] Since the residual internal stress index is 25% or less (specifically, when a tensile test is performed on the laminated film, the residual internal stress index is 25% or less in both the flow direction and the width direction of the laminated film), it is possible to reduce or prevent the peeling of the paint substitute film from the resin parts (specifically, resin plates) that may occur during molding such as hot press molding, hot bending molding, and vacuum forming. Specifically, when the paint substitute film of this embodiment is laminated onto a resin plate, and then the laminated resin plate (hereinafter sometimes referred to as "film-coated resin laminate" or "laminated plate") including the resin plate and the paint substitute film laminated onto the resin plate is molded (for example, by hot press molding, hot bending molding, vacuum forming, etc.), it is possible to reduce or prevent the occurrence of peeling of the paint substitute film that may occur. This will be explained below. The residual index of internal stress is expressed by the following formula: The residual index of internal stress = |1 - (Ub / Ua)| × 100 =|(Ua-Ub) / Ua|×100 The Ua and Ub in this equation can be determined based on the stress-strain curve obtained from a tensile test (specifically, a tensile test in which a 15 mm wide specimen is gripped by a pair of chucks with a distance of 50 mm between the chucks, the distance between the chucks is increased at a tensile speed of 1000 mm / min and 100°C until a 20% strain occurs, and then the distance between the chucks is returned to 50 mm at a speed of 2000 mm / min and 100°C). Here, the stress-strain curve is a graph in which stress is plotted on the vertical axis and strain on the horizontal axis (see Figure 1). As shown in Figure 1, Ua is a value obtained by integrating the stress-strain curve from 0% strain to the yield strain, i.e., the strain indicating the yield point. If we consider the period from the start of tension to the occurrence of yield strain as elastic deformation, then Ua can be considered as the elastic strain energy stored in the laminated film due to tension. On the other hand, Ub is a value obtained by integrating from 20% strain down to the strain at which the stress is 0 MPa (hereinafter sometimes referred to as "rebound strain" or "rebound strain amount"). Ub is the energy released when the distance between the chucks returns from the distance at which 20% strain is applied back to the distance between the chucks at the start of tension (50 mm), that is, when the deformation of the laminated film (specifically, the deformation applied to the laminated film by tension) recovers, and therefore can be said to be elastic strain energy. If the balance between Ua and Ub is excessively poor, the warping that occurs when the laminate resin sheet is molded (i.e., the warping of the laminate resin sheet) will not effectively release the elastic strain energy of the laminated film (specifically, the elastic strain energy stored in the laminated film during molding). In other words, the elastic strain energy will not effectively decrease, resulting in excessive internal stress remaining in the laminated film. In contrast, according to this embodiment, the value calculated by |(Ua-Ub) / Ua| × 100 (i.e., the residual internal stress index rate) is 25% or less. Therefore, the warping that occurs when the laminate resin sheet is formed (i.e., the warping of the laminate resin sheet) can effectively release the elastic strain energy of the laminated film, and thus, excessive internal stress can be avoided in the laminated film. As a result, the occurrence of peeling of the coating substitute film that may occur when the laminate resin sheet is formed can be reduced or prevented. Furthermore, when a laminated resin sheet is obtained by laminating the paint substitute film of this embodiment onto a resin sheet for vehicles, and the laminated resin sheet is then molded into a vehicle exterior part, the occurrence of peeling of the paint substitute film can be further reduced or prevented. This is because, when the laminated resin sheet is molded, the paint substitute film stretches partially, and this stretch is generally considered to be at most about 20% in vehicle exterior parts. The vehicle used is preferably an automobile, and more preferably a four-wheeled vehicle. The residual internal stress index can be controlled by, for example, the surface orientation coefficient of layer B and the ratio of the thickness of layer B to the thickness of the laminated film. The higher the surface orientation coefficient of layer B, the lower the residual internal stress index tends to be. The larger the ratio (specifically, the ratio of the thickness of layer B to the thickness of the laminated film), the lower the residual internal stress index tends to be.

[0015] Furthermore, because the surface orientation coefficient of layer B is 0.165 or higher, it is possible to reduce the occurrence of tearing, cracks, and pinholes in the coating substitute film that may occur when the laminate resin sheet is molded (e.g., hot press molding, hot bending molding, vacuum forming, etc.). In addition, it is possible to prevent an excessive decrease in image clarity that may occur when the laminate resin sheet is molded (e.g., hot press molding, hot bending molding, vacuum forming, etc.). In other words, since the surface orientation coefficient of layer B is 0.165 or higher, the appearance of the laminate resin sheet can be improved.

[0016] Embodiments of the present invention will be described in more detail below. The flow direction may be referred to as the Machine Direction or MD direction. The width direction may be referred to as the Transverse Direction or TD direction. The stress at 20% elongation may be referred to as the F20 value or 20% strain tensile stress. Strain may be referred to as strain amount. The laminated film may be referred to as the base film.

[0017] The paint-alternative film of this embodiment includes a colored layer, a first adhesive layer, a laminated film, and a second adhesive layer. In the paint-alternative film of this embodiment, the colored layer, the first adhesive layer, the laminated film, and the second adhesive layer may be arranged in this order.

[0018] The paint-alternative film of this embodiment may further include a protective film and a surface protective layer. In this case, the paint-alternative film of this embodiment may have the protective film, surface protective layer, coloring layer, first adhesive layer, laminated film, and second adhesive layer arranged in this order. In other words, the paint substitute film of this embodiment may include at least a protective film, a surface protective layer, a coloring layer, a first adhesive layer, a base film, and a second adhesive layer in this order. The present invention may also include other layers between each layer, or another layer further outside the outermost layer.

[0019] (Base film) The base film, i.e., the laminated film, included in the paint-alternative film of the present invention includes layers A and B. The paint-alternative film of this embodiment may further include other layers in addition to layers A and B. The other layers are preferably mainly composed of polyester, and more preferably crystalline polyester. Crystalline polyester will be described later.

[0020] Layers A and B are mainly composed of polyester. Here, "mainly composed of" means that polyester makes up preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the film.

[0021] The polyester constituting layer A is preferably a crystalline polyester. Here, a crystalline polyester refers to a polyester in which, when 10 mg of the polyester composition scraped from layer A is heated to 290°C at a rate of 20°C / min using a DSC-60 differential scanning calorimeter, is kept isothermal for 3 minutes, rapidly cooled at a rate of 200°C / min, and then heated again to 290°C at a rate of 10°C / min, a baseline shift corresponding to the glass transition point and an endothermic peak of 0.05 J / g or more associated with crystal melting are observed at a temperature higher than the baseline shift. The polyester constituting layer A can be a homopolyester or a copolymer polyester. Preferably, it is a copolymer polyester with a eutectic point of 160°C to 250°C, and more preferably a copolymer polyester with a melting point of 180°C to 250°C. The copolymer polyester is preferably mainly composed of ethylene terephthalate units. Here, "main component" means that in the copolymerized polyester, the ethylene terephthalate unit is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more.

[0022] The copolymer components of such copolymerized polyester may be either acidic or alcoholic components. Examples of acidic components include aromatic dicarboxylic acids other than the main acidic components such as isophthalic acid, phthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid, as well as aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid. Examples of alcoholic components include ethylene glycol, trimethylene glycol, and tetramethylene glycol, as well as polyoxyalkylene glycols such as diethylene glycol. In addition, examples include aliphatic diols such as 1,6-hexanediol and alicyclic diols such as 1,4-cyclohexanedimethanol. These can be used individually or in combination of two or more. Among these, isophthalic acid and sebacic acid are preferred, and isophthalic acid is particularly preferred.

[0023] The crystalline polyester content in layer A is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of layer A.

[0024] The polyester constituting layer B is preferably a crystalline polyester. Here, a crystalline polyester refers to a polyester in which, when 10 mg of the polyester composition scraped from layer B is heated to 290°C at a rate of 20°C / min using a DSC-60 differential scanning calorimeter, is kept isothermal for 3 minutes, rapidly cooled at a rate of 200°C / min, and then heated again to 290°C at a rate of 10°C / min, a baseline shift corresponding to the glass transition point and an endothermic peak of 0.05 J / g or more associated with crystal melting are observed at a temperature higher than the baseline shift.

[0025] The polyester constituting layer B can be a homopolyester or a copolymerized polyester. Preferably, it is a polyester with a melting point between 250°C and 260°C, and particularly preferably homopolyethylene terephthalate. Note that the term homopolyethylene terephthalate here does not exclude the inclusion of diethylene glycol components, which are inevitably present.

[0026] The crystalline polyester content in layer B is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on 100% by mass of layer B.

[0027] In the present invention, it is preferable that the melting point TmB of layer B is higher than the melting point TmA of layer A. When the melting point TmB is higher than the melting point TmA, layer A can relieve the stress generated in the paint substitute film when the laminate resin sheet is formed, and therefore, the occurrence of delamination of the paint substitute film can be reduced or prevented. In addition, when the melting point TmB is higher than the melting point TmA, the moldability tends to improve. That is, it tends to reduce the occurrence of tears, cracks, and pinholes in the paint substitute film that may occur when the laminate resin sheet is formed. The melting point difference: TmB-TmA is preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 35°C or lower. When the above melting point difference is 20°C or higher, or 25°C or higher, layer A can further relieve the stress generated in the paint substitute film when the laminate resin sheet is formed, and therefore, the occurrence of delamination of the paint substitute film can be further reduced or prevented. On the other hand, by having a melting point difference of 35°C or less, the surface orientation coefficients of layers A and B can be controlled within a predetermined range, suppressing the effects of heating and shear heat during molding and enabling uniform molding, which contributes to improved adhesion to resin components and moldability.

[0028] The intrinsic viscosity (i.e., IV) of the polyester used in layers A and B is preferably 0.60 or higher and less than 0.95. When the intrinsic viscosity is above the lower limit, the film manufacturing operation is good and the generation of thermally degraded products derived from low molecular weight materials can be suppressed. Furthermore, it is preferable because it is possible to prevent excessive internal stress generated during the molding process of the resin component from remaining in the laminated film, and excellent adhesion to various resins and excellent moldability can be achieved. On the other hand, when the viscosity is below the upper limit, adhesion is good and the lamination processability with the resin component is improved.

[0029] In the present invention, the surface orientation coefficient of layer B is preferably 0.165 or higher, more preferably 0.166 or higher, even more preferably 0.167 or higher, even more preferably 0.168 or higher, and even more preferably 0.170 or higher. By having a surface orientation coefficient of 0.165 or higher for layer B, it is possible to prevent excessive internal stress generated during the molding process of the resin member from remaining in the laminated film. The surface orientation coefficient of layer B is preferably 0.180 or lower, and more preferably 0.178 or lower. It is preferable that the surface orientation coefficient of layer A is smaller than that of layer B, and it is preferable that the difference between the surface orientation coefficient of layer B and the surface orientation coefficient of layer A is 0.030 or higher.

[0030] When laminating a paint substitute film to complex shapes such as exterior parts of automobiles, the paint substitute film is partially stretched significantly in curved areas, and is fixed with an adhesive (i.e., a second adhesive layer) while under strain from this stretching. As a result, areas of localized strength and weakness occur in the bonding force between the resin member and the paint substitute film. Layer A in the above-mentioned base film has the function of relieving the stress generated by the physical bonding between the second adhesive (i.e., the second adhesive layer) and the resin member. On the other hand, layer B functions as a base material for multiple processes in creating the paint substitute film, and also uniformly distributes the stress generated by the physical bonding with the resin member, which has been relieved by layer A, in the planar direction through the orientation of the film surface of layer B, thereby preventing excessive internal stress generated during molding from remaining in the laminated film. With layers A and B having these functions, excellent adhesive strength and excellent moldability can be achieved for various resins.

[0031] In the present invention, the coating substitute film preferably has a 20% elongation stress (F20) of 60 MPa or higher in both the flow direction and the width direction of the laminated film including layers A and B, under tensile conditions at 100°C. More preferably, it is 65 MPa or higher, and even more preferably 70 MPa or higher. By having a stress of 60 MPa or higher, the stress of the coating substitute film can be maintained even during the molding process of the resin component, ensuring uniform moldability. The upper limit of the F20 value is not particularly limited, but it is preferably 110 MPa or lower, and more preferably 105 MPa or lower.

[0032] In the present invention, it is preferable that the coating substitute film has a residual rate of internal stress (i.e., residual index rate) of 25% or less in both the flow direction and the width direction of the base film (i.e., laminated film) including layers A and B, in a tensile test under 100°C conditions, as shown in the following formula 1. (Equation 1) Percentage of remaining internal stress (%) = |1 - (Ub / Ua)| × 100 Here, the above tensile test is performed using a sample with a specimen width of 15 mm, with a chuck distance of 50 mm, pulling at a tensile speed of 1000 mm / min until 20% elongation, and then returning to a chuck distance of 50 mm at a speed of 2000 mm / min after 20% elongation. Ua refers to the elastic strain energy from the starting point 0 to the yield point in the stress-strain curve obtained from the above tensile test, and Ub refers to the elastic strain energy when returning from 20% elongation to the chuck distance in the stress-strain curve obtained from the above tensile test.

[0033] In other words, when a tensile test is performed on a laminated film (specifically, a 15 mm wide test piece cut from the laminated film is gripped by a pair of chucks with a distance of 50 mm between the chucks, and the distance between the chucks is widened at a tensile speed of 1000 mm / min and 100°C until a 20% strain occurs, and then the distance between the chucks is returned to 50 mm at a speed of 2000 mm / min and 100°C), the residual index of internal stress shown in Equation 1 is 25% or less in both the flow direction and the width direction of the laminated film. Ua is a value obtained by integrating the stress-strain curve from a tensile test from 0% strain to the yield strain (i.e., the strain indicating the yield point). In other words, it is the area of ​​the region enclosed by the stress-strain curve and the portion of the horizontal axis from 0% strain to the yield strain. Ub is a value obtained by integrating the stress-strain curve from 20% strain to the strain where the stress is 0 MPa (i.e., "rebound strain"). In other words, it is the area of ​​the region between the stress-strain curve and the portion of the horizontal axis from 20% strain to rebound strain. Furthermore, considering that heat is generally applied to soften the resin when forming laminate resin sheets, the tensile test used to determine Ua and Ub is a 100°C tensile test.

[0034] In both the flow direction and the width direction of the laminated film, the residual index rate of internal stress, i.e., the residual rate, may be 23% or less, 20% or less, or 17% or less.

[0035] Furthermore, in the flow direction of the laminated film, Ub may be greater than or less than Ua. In the width direction of the laminated film, Ub may be greater than or less than Ua. In both the flow direction and the width direction of the laminated film, Ub may be greater than or less than Ua.

[0036] When molding a resin component laminated with a paint substitute film, warping (i.e., warping of the laminated resin sheet) may occur if a load is applied until a certain amount of deformation is reached and then the load is removed. In this case, if the residual internal stress of the paint substitute film is high, the film may not be able to follow the warping (i.e., warping of the laminated resin sheet), which may result in tearing or delamination of the film. Since the residual internal stress of the paint substitute film is 25% or less, it is possible to prevent excessive internal stress generated when the laminated resin sheet is molded from remaining in the laminated film, and it is estimated that excellent adhesion and excellent moldability can be achieved for various resins. The residual internal stress can be kept within the above range by controlling the intrinsic viscosity and surface orientation coefficient of layers A and B to a predetermined range.

[0037] The coating substitute film of the present invention preferably has a sum of the thermal shrinkage rate in the flow direction and the thermal shrinkage rate in the width direction after heat treatment at 150°C for 15 minutes of the laminated film including layers A and B, which is 5.0% or less. If it exceeds 5.0%, the adhesion force during heat lamination is low, requiring a high lamination temperature near or above the melting point, which is undesirable in practice and also undesirable from the viewpoint of dimensional stability during thermoforming. The sum of the thermal shrinkage rates is preferably 4.8% or less. The sum of the thermal shrinkage rates may be, for example, 4.5% or less, 4.2% or less, or 4.0% or less. Methods for achieving the above thermal shrinkage rates include appropriately setting the stretching conditions and heat setting treatment conditions. The sum of the thermal shrinkage rate in the flow direction and the thermal shrinkage rate in the width direction after heat treatment at 150°C for 15 minutes may be 1.0% or more, 2.0% or more, or 3.0% or more. The thermal shrinkage rate can be calculated using the following formula. Thermal shrinkage rate (%) = {(L0 - L) / L0} × 100 Here, L is the gauge length after heat treatment (specifically, heat treatment at 150°C for 15 minutes), and L0 is the gauge length before heat treatment (specifically, heat treatment at 150°C for 15 minutes).

[0038] The thickness of the laminated film of the present invention can be changed as needed, but a range of 15 to 200 μm is preferable for the overall thickness, with a range of 20 to 150 μm being particularly preferable, and a range of 30 to 100 μm being especially preferable. A thickness of 15 μm or more provides good handling in the film formation, coating, and lamination processes. On the other hand, a thickness of 200 μm or less helps to prevent excessive load during molding.

[0039] The thickness of layer A is preferably 5 μm or more, and more preferably 8 μm or more. Having layer A at 5 μm or more allows for stress relaxation of the film during molding after lamination with the resin, such as during hot pressing, heat bending, or vacuum forming, thus facilitating adhesion between the film and the resin sheet. Furthermore, the thickness ratio of layer A to layer B (XB / XA: where XA is the total thickness of layer A and XB is the total thickness of layer B) is preferably 1.5 or more, and more preferably 2.0 or more, from the viewpoint of balancing improved adhesion between the film and the resin sheet with maintaining a good appearance. The ratio of the thickness of layer B to the thickness of the laminated film, i.e., the thickness of layer B / thickness of the laminated film, is preferably 0.50 or more, more preferably 0.60 or more, even more preferably 0.65 or more, and even more preferably 0.70 or more. On the other hand, this ratio is preferably 0.95 or less, and more preferably 0.90 or less.

[0040] Other additives, such as coloring pigments (i.e., colorants), fluorescent whitening agents, antioxidants, heat stabilizers, ultraviolet absorbers, and antistatic agents, may be added to layers A and B as needed, within a range that does not hinder the objectives of the present invention. When the laminated film is used as an opacity layer, the addition of coloring pigments is preferable, and they may be inorganic or organic, but inorganic is preferred. Examples of inorganic pigments include alumina, titanium dioxide, calcium carbonate, and barium sulfate, with titanium dioxide being more preferred. The content of the coloring pigment is preferably more than 2% by mass and 50% by mass or less based on the mass of layer B, a more preferable content is in the range of 5 to 40% by mass, and even more preferably in the range of 10 to 35% by mass. Fluorescent whitening agents may be used to particularly improve whiteness. In addition, inert particles may be added to improve handling in the film-forming and molding processes. The inert particles to be included are not particularly limited as long as they can exist stably in the polymer, and known particles can be used. For example, polymers or copolymers of monomers selected from polystyrene, methyl polyacrylate, ethyl polyacrylate, methyl polymethacrylate, ethyl polymethacrylate, and divinylbenzene, or organic materials such as polytetrafluoroethylene, polyacrylonitrile, benzoguanamine, and silicone, or inorganic materials such as silica, kaolin, talc, and graphite are preferred. The preferred particle size of these inert particles is 0.1 to 10 μm. Layer B may contain inert particles, layer A may contain inert particles, or both may contain inert particles. The content of inert particles in the laminated film is preferably in the range of 0.002 to 0.5% by mass of 100% by mass of the laminated film. If layer B contains inert particles, the content of inert particles is preferably in the range of 0.002 to 0.5% by mass of 100% by mass of layer B. On the other hand, if layer A contains inert particles, it is preferable that the amount of inert particles is in the range of 0.002 to 0.5 mass% of 100 mass% of layer A. Furthermore, if the laminated film contains a coloring pigment, i.e., a coloring agent, then layer A may contain the coloring agent, layer B may contain it, or both layers A and B may contain the coloring agent. Of course, the laminated film does not have to contain colorants. That is, neither layer A nor layer B can contain colorants.

[0041] The manufacturing method for layers A and B in this invention is not particularly limited, and conventionally known film-forming methods can be applied. For example, when manufacturing a biaxially oriented laminated film, an unstretched laminated sheet is first prepared, and then stretched in two directions. Typical examples are shown below.

[0042] For example, a polyester composition is prepared for layer A by adding inert particles to polyester, and after being thoroughly dried, it is melted in an extruder at a temperature of ~(melting point + 50)°C. Here, the melting point is the melting point of the polyester used. Simultaneously, a polyester composition is prepared for layer B by adding inert particles to crystalline polyester, and after being thoroughly dried, it is supplied to another extruder and melted at a temperature of ~(melting point + 50)°C. Subsequently, a laminated unstretched laminated sheet is produced by a method of laminating both molten resins inside a die, for example, a simultaneous lamination extrusion method using a multi-manifold die. In this simultaneous lamination extrusion method, the molten resin forming one layer and the molten resin forming the other layer are laminated inside the die and formed into a sheet from the die while maintaining the laminated structure.

[0043] The unstretched laminated sheet can then be manufactured by sequential or simultaneous biaxial stretching and heat-fixing. When forming a film by sequential biaxial stretching, the unstretched laminated sheet is heated by roll heating, infrared heating, etc., and first stretched in the flow direction, and then stretched transversely with a tenter. At this time, the lower limit of the stretching temperature in the flow direction is preferably 70°C, and more preferably 80°C. If the temperature is below 70°C, not only is breakage more likely to occur, but the orientation in the flow direction becomes stronger due to stretching at low temperatures, so the shrinkage stress during the heat-fixing treatment becomes larger, which increases the strain of the molecular orientation in the width direction, and as a result the processability during molding may decrease. The upper limit of the stretching temperature in the flow direction is preferably 110°C, and more preferably 100°C. If the temperature exceeds 110°C, the orientation decreases, which may reduce the processability during molding.

[0044] The lower limit of the stretching ratio in the flow direction is preferably 3 times, and particularly preferably 3.5 times. If it is less than the above, the orientation will decrease, which will reduce processability during molding, and uneven thickness may cause sagging in the film roll. The upper limit of the stretching ratio in the flow direction is preferably 5.0 times, more preferably 4.5 times, and particularly preferably 4.0 times. If it exceeds the above, the effects of improving mechanical strength and thickness uniformity may saturate. Stretching in the flow direction can be performed, for example, by heating the unstretched film with heated rolls or infrared radiant heat in a roll stretching machine and stretching it using the speed difference between the rolls.

[0045] The lower limit of the stretching temperature in the width direction is preferably 90°C; below this temperature, fracture may be more likely to occur. The upper limit of the TD stretching temperature is preferably 130°C; exceeding this temperature may reduce the orientation and thus the processability during molding.

[0046] The lower limit of the stretching ratio in the width direction is preferably 3.0 times, and more preferably 3.5 times. If it is less than the above, the degree of orientation in the width direction will be small, which will reduce processability during molding and may cause sagging in the film roll due to thickness unevenness. The upper limit of the stretching ratio in the width direction is preferably 5.0 times, and more preferably 4.5 times. If it exceeds the above, the effects of processability during molding and improvement of thickness unevenness may saturate.

[0047] After the biaxial stretching described above, it is preferable to perform a heat-setting treatment. The heat-setting temperature is preferably selected in the range of 150 to 230°C according to the melting point of the polyester in order to adjust the film quality. At this time, if the temperature is too low, the adhesion to the resin plate deteriorates, and if it is too high, the surface orientation coefficient decreases, preventing the function of suppressing elastic strain energy from being exhibited, leading to deterioration of adhesion to the resin member and moldability. Taking this into consideration, the heat-setting temperature is preferably 205°C or higher, more preferably 210°C or higher, and even more preferably 215°C or higher.

[0048] It is preferable to perform a thermal relaxation treatment in conjunction with or separately from the thermal setting treatment. In the thermal relaxation treatment, it is preferable to relax in at least one of the flow direction (i.e., MD direction) and the width direction (i.e., TD direction). In particular, relaxation in the width direction is preferable. When relaxing in the width direction, the relaxation rate in the width direction is preferably 3% or more, and more preferably 4% or more. If it is 3% or more, the thermal shrinkage rate can be effectively reduced. On the other hand, the relaxation rate in the width direction is preferably 8% or less, and more preferably 7% or less.

[0049] (First adhesive layer) One preferred embodiment of the present invention is a paint substitute film in which a first adhesive layer is laminated on the B-layer side surface of a substrate film comprising at least two layers, A-layer and B-layer. The first adhesive layer has the function of improving the adhesion between the laminated film and the colored layer described later. In other words, the first adhesive layer can act as an easy-adhesion layer. Therefore, the first adhesive layer can be rephrased as an easy-adhesion layer. The first adhesive layer preferably contains a resin having at least one functional group selected from the group consisting of epoxy groups, oxazoline groups, silanol groups, and isocyanate groups. Among these, it is preferable to contain an epoxy group or an oxazoline group from the viewpoint of obtaining excellent adhesion and vividness with the B-layer. The thickness of the first adhesive layer is preferably 10 nm or more, more preferably 15 nm or more, even more preferably 20 nm, and particularly preferably 40 nm or more from the viewpoint of adhesion. On the other hand, the upper limit of the thickness is preferably 200 nm or less, more preferably 180 nm, even more preferably 150 nm, and particularly preferably 120 nm or less, from the viewpoint of reducing unevenness in coating thickness and adhesion.

[0050] As mentioned above, the first adhesive layer preferably contains at least one functional group selected from the group consisting of epoxy groups, oxazoline groups, silanol groups, and isocyanate groups. The resin forming the first adhesive layer can be any known resin that has excellent adhesion to the base film or colored layer. To adjust the adhesive strength, copolymerization of each resin or blending of different resins can be suitably used to improve the adhesive strength. For example, any of the following can be used, either alone or in combination of two or more: polyurethane resins, vinyl chloride / vinyl acetate copolymer resins, vinyl chloride / vinyl acetate / acrylic copolymer resins, chlorinated polypropylene resins, acrylic resins, polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, cellulose acetate resins, etc. Molding processes such as hot pressing, hot bending, or vacuum forming can reach a molding temperature of around 150°C, so it is preferable that the glass transition temperature is designed to be lower than this temperature, and acrylic resins and polyester resins can be preferably used.

[0051] The first adhesive layer described above may be applied by in-line coating, which is performed while the base film is being formed, or the base film may be wound into a roll after it has been formed, and then unwound again for off-line coating.

[0052] The resulting first adhesive layer contributes to improving the adhesion between the base film and the colored layer when laminating the colored layer onto the base film by forming bonds between functional groups, reducing interlayer interface energy, and promoting interlayer interface mixing.

[0053] (Second adhesive layer) One preferred embodiment of the present invention is a paint substitute film in which a second adhesive layer is laminated on the A-layer side surface of a substrate film comprising at least two layers, A-layer and B-layer. The second adhesive layer has the function of improving the adhesion between the paint substitute film and the resin substrate.

[0054] The second adhesive layer may contain an adhesive. The resin contained in the adhesive of the second adhesive layer, i.e., the resin forming the second adhesive layer, can be any known resin as long as it has excellent adhesion to the base film (i.e., laminated film) or resin base material. To adjust the adhesive strength, copolymerization of each resin or blending different resins to improve the adhesive strength can be suitably used. For example, any of the following can be used, either alone or in combination of two or more: polyolefin resins, polyurethane resins, vinyl chloride / vinyl acetate copolymer resins, vinyl chloride / vinyl acetate / acrylic copolymer resins, chlorinated polypropylene resins, acrylic resins, polyester resins, polyamide resins, butyral resins, polystyrene resins, nitrocellulose resins, cellulose acetate resins, etc. Since molding processes by hot pressing, hot bending, or vacuum forming may reach a molding temperature of around 150°C, it is preferable that the glass transition temperature be lower than this temperature, and polyolefin resins, acrylic resins, and polyester resins can be preferably used. Among these, polyolefin resins and acrylic resins are more preferable. Furthermore, in order for the adhesive function between the laminated film and the resin substrate to be fully exhibited, the second adhesive layer in the present invention is preferably 15 to 30 μm thick.

[0055] The second adhesive layer described above may be applied by in-line coating, which is performed while the base film is being formed, or the base film may be wound into a roll after film formation, and then unwound again for off-line coating.

[0056] (colored layer) One preferred embodiment of the present invention is a paint-alternative film in which a coloring layer and a surface protection layer are laminated in this order on the B-layer side surface of a base film comprising at least two layers, A and B, via a first adhesive layer. Laminating each layer in this order is preferable because it ensures good adhesion between the base film and the coloring layer, and furthermore, allows for the expression of an excellent appearance and design.

[0057] The above-mentioned colored layer preferably contains a binder resin and at least one coloring agent selected from the group consisting of pigments and dyes, and from the viewpoint of design, it is preferable that the coloring agent is contained in an amount of 0.5% by mass or more and less than 40% by mass, based on the mass of the composition used for the colored layer. A more preferable range is 2% by mass or more and less than 30% by mass, and a particularly preferable range is 5% by mass or more and less than 25% by mass. If a binder resin is not used, cracks may easily occur in the colored layer due to the elongation during molding, which may impair the aesthetic appearance. Furthermore, by using a pigment or dye, a beautiful and superior appearance can be formed. The pigment or dye used is preferably one or more selected from the group consisting of carbon black (ink), iron black, titanium white, antimony white, lead yellow, titanium yellow, iron oxide, cadmium red, ultramarine, cobalt blue, quinacridone red, isoindolinone yellow, phthalocyanine blue, aluminum, brass, titanium dioxide, and pearlescent pigments. The use of other pigments and additives for color matching is a preferred embodiment, as long as it does not impair the effects of the present invention.

[0058] The method for forming the above-mentioned colored layer is not particularly limited, but a method of lamination by coating is simple and preferred. The adhesion between the above-mentioned colored layer and the above-mentioned B layer can be appropriately adjusted depending on the type of resin used for the B layer and the first adhesive layer, and the binder resin used for the colored layer.

[0059] The thickness of the above-mentioned colored layer is preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the thickness is preferably 100 μm or less, more preferably 75 μm or less, even more preferably 50 μm or less, even more preferably 45 μm or less, and even more preferably 30 μm or less. When the above-mentioned colored layer is used on the exterior of a vehicle, it is also preferable to make it a multi-layered colored layer in order to produce a beautiful design. For example, it is preferable to make it a two-layered colored layer by providing a colored layer containing a glossy material pigment in a binder resin on top of a colored layer made of pigment. Furthermore, considering the reflective properties from the viewing side, it is also preferable to make it a three-layered colored layer with a colored reflective layer made of aluminum pigment, a colored pigment layer, and a glossy material pigment layer of a clear coating film on the side of the colored layer closest to the laminated film. Using the colored layer as a single layer or as a multi-layered layer in order to impart the desired design properties does not in any way negate the purpose of the present invention.

[0060] (Surface protective layer) The resin used for the surface protection layer described above preferably consists mainly of at least one type of resin selected from the group consisting of thermosetting resins or photocurable resins, due to its suitability for the manufacturing process from paint substitute film production to resin component molding. In other words, the surface protection layer preferably has thermosetting or photocuring properties. Thermosetting is preferred among these. The surface protection layer is required to have weather resistance, scratch resistance, and transparency, and as an example, an acrylic resin can be used.

[0061] The thickness of the surface protective layer described above is preferably 5 to 80 μm after drying. If the thickness of the surface protective layer is greater than the lower limit, less resin material is used, resulting in good cost performance, but it is not possible to maintain a high level of protection against scratches and chemicals in the inner colored layer, laminated film, and the components after they have been made. On the other hand, if the thickness is less than the upper limit, it is good in terms of gloss and protective performance as a hard coat coating, but it is not economically viable because more resin is used than necessary. The thickness of the surface protective layer described above is more preferably 10 to 60 μm, and even more preferably 15 to 50 μm.

[0062] The above surface protection layer may consist of a single layer or multiple layers. For example, when coating with multiple layers of the same resin twice, the degree of curing can be adjusted by varying the drying conditions, and adhesion can be improved when a functional layer such as an anti-fouling layer is added to the outside of the surface protection layer. Furthermore, a glossy surface can be produced by creating multiple layers within the above range.

[0063] The above surface protection layer is preferably laminated by coating onto a colored layer (specifically, a colored layer laminated on a base film). The method can be any known coating method, but it is preferable to roll it up in a state where the heat curing is not yet complete (hereinafter sometimes referred to as "semi-cured state"). When the hard coat paint is dried, the primary reaction proceeds due to heat, and the hard coat becomes a coating film in a semi-cured state, making it possible to roll it up. The semi-cured surface protection layer can then be designed so that the secondary reaction proceeds at a temperature higher than the aforementioned drying temperature, thereby allowing the degree of curing to progress from semi-cured to fully cured by the heat generated when laminating onto a resin plate or when molding a component.

[0064] (Protective film) One preferred embodiment of the present invention is a paint substitute film in which a colored layer and a surface protection layer are laminated in that order on the B-layer side surface of a base film comprising at least two layers, A and B, via a first adhesive layer, and further having a protective film on the surface protection layer. The protective film has functions such as an anti-fouling layer to prevent soiling during outdoor use and to improve handling in the manufacturing process. In particular, when the surface protection layer is laminated in a semi-cured state, it is preferable to laminate the protective film to improve handling in subsequent processes. The protective film may be peeled off at any time, but from the viewpoint of scratch resistance, it is preferable to peel it off after heat-press lamination with the resin plate and molding of the film-coated resin laminate (for example, hot pressing, heat bending, or vacuum forming). Examples of protective films include films made of polyethylene resin, polyester resin (for example, polyethylene terephthalate resin, polyethylene naphthalate resin, copolymerized polyester resin, etc.), copolymerized polyester resin, polypropylene resin, polyvinyl chloride resin, and mixtures thereof. Among these, polyethylene resin and copolymerized polyester resin are preferred. This is because these materials have a high ability to follow the deformation of the resin sheet when forming the laminate resin sheet. In other words, polyethylene resin and copolymerized polyester resin have excellent conformability. Furthermore, copolymerized polyester resin may be preferable when considering heat resistance and uniform moldability. Examples of copolymerized polyester resins include copolymerized polyethylene terephthalate resin and copolymerized polyethylene naphthalate resin. Among these, copolymerized polyethylene terephthalate resin is preferred. Examples of copolymerization components for obtaining copolymerized polyethylene terephthalate resin, especially dicarboxylic acids, include aromatic carboxylic acids such as isophthalic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid; and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Among these, isophthalic acid is preferred. One or more of these can be used.Examples of copolymer components for obtaining copolymerized polyethylene terephthalate resin, particularly diols, include aliphatic diols such as butanediol and hexanediol; and alicyclic diols such as cyclohexanedimethanol. One or more of these can be used. The thickness of the protective film is not particularly limited, but a thickness of 15 to 150 μm is preferred to ensure sufficient protective function.

[0065] The thickness of the protective film is preferably 10 μm or more, more preferably 25 μm or more, and even more preferably 38 μm or more. A thickness of 10 μm or more provides excellent rigidity. The thickness of the protective film is preferably 150 μm or less, more preferably 100 μm or less, even more preferably 75 μm or less, and even more preferably 50 μm or less. This is because a thinner protective film is more economical. The protective film may be a single-layer or multi-layer structure.

[0066] Of the two surfaces of the protective film described above, the surface roughness of at least the surface in contact with the surface protective layer is preferably 1 nm or more, more preferably 3 nm or more, and even more preferably 10 nm or more. If it is 10 nm or more, the protective film has good transportability and therefore good handling. The surface roughness is preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably 500 nm or less. Since the surface shape of the protective film can be transferred to the surface protective layer, if the surface roughness is 1000 nm or less, it is possible to prevent deterioration of the appearance of the surface protective layer as a result.

[0067] It is preferable that at least one of the two surfaces of the protective film described above, the surface in contact with the surface protective layer, is subjected to a delamination treatment. For the delamination treatment, for example, a silicone-based delaminator, a fluorine-based delaminator, or a long-chain aliphatic delaminator can be used. Among these, a silicone-based delaminator is preferred.

[0068] The protective film described above can be formed on the surface protective layer by any method. For example, the protective film can be formed by coating, melt extrusion, lamination, etc., but it is preferable to laminate individually manufactured protective films.

[0069] (Film-coated resin laminate) The present invention further provides a film-coated resin laminate in which a resin plate is laminated onto the above-mentioned paint-alternative film. The film-coated resin laminate in the present invention may be formed by laminating the resin plate and the above-mentioned base film with a second adhesive layer in between by thermal lamination. The resin plate is usually fed out in single sheets, and the paint-alternative film is laminated in roll form.

[0070] A preferred method for manufacturing a film-coated resin laminate is to heat a resin plate and then press the second adhesive side (i.e., the second adhesive layer) of the supplied coating substitute film against the resin plate using a nip roll (for example, by pressing at 130°C), thereby bonding the film to the resin plate. In other words, a heated resin plate and a coating substitute film can be pressed together to obtain a laminate.

[0071] The resin sheet used for heat-sealing can be appropriately selected from known types according to the intended use of the resin component. Examples include polyolefin resin, polyamide resin, polycarbonate resin, polyphenylene sulfide resin, and polyester resin. Among these, polyolefin resin and polyester resin are preferred. Polyolefin resin is more preferred. One or more of these can be used. The resin sheet may contain reinforcing fibers. That is, the resin composition of the resin sheet may contain reinforcing fibers. The resin composition may also contain additives. For vehicle exterior parts, resin sheets with good moldability and a thickness of about 1.0 to 6.0 mm are generally used, so it is preferable to use such grades.

[0072] (Resin component) The present invention further provides a resin member, i.e., a molded product, obtained by molding the above-mentioned film-coated resin laminate. Preferred molding methods include hot pressing, hot bending, or vacuum forming. When performing hot pressing with the above-mentioned film-coated resin laminate, whether it is stretch molding in which the edges of the resin plate are held under high pressure, or molding in which the resin plate is held under low pressure and sucked in during molding (steam molding), by pre-applying the film to the surface of the resin plate as described above, it becomes possible to coat the surface of the resin member with a paint substitute film.

[0073] The above-mentioned resin material is preferably used in vehicle exterior parts for automobiles, motorcycles, and other vehicles. Vehicle exterior parts require excellent appearance and design, and the present invention can be suitably used in such applications. Exterior panels are preferred as vehicle exterior parts. The present invention is not limited to these applications and may also be used in ships (motorboats, etc.), home appliances, audio products, and the like. [Examples]

[0074] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each characteristic value is measured by the following method. Furthermore, unless otherwise specified, parts and % in the examples refer to parts by mass and mass%, respectively. In this embodiment, "flow direction" refers to the flow direction of the base film. In this embodiment, the flow direction of the base film is also the flow direction of the coating substitute film. In this embodiment, "width direction" refers to the width direction of the base film. In this embodiment, the width direction of the base film is also the width direction of the coating substitute film.

[0075] (A) Method for measuring intrinsic viscosity 0.2 g of polyester resin was dissolved in 50 ml of a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (60 / 40 (mass ratio)) and measured using an Ostwald viscometer at 30°C. The unit is dl / g.

[0076] (B) Method for measuring the melting point (Tm) Measurements were taken using a DSC-60 differential scanning calorimeter (Shimadzu Corporation). Polyester resin was heated and melted at 300°C for 5 minutes, then rapidly cooled with liquid nitrogen. 10 mg of the rapidly cooled polyester resin was used as a sample, and the endothermic peak temperature (melting point) based on crystal melting that appeared when the temperature was increased at a rate of 20°C / min was measured. The melting points of layers A and B of the film were measured in the same manner as above, using samples scraped from the respective surfaces of layers A and B of the base film, i.e., the polyester film. Here, the melting point peak was defined as an endothermic peak of 0.05 J / g or more associated with crystal melting, located at a temperature higher than the baseline shift corresponding to the glass transition point.

[0077] (C) Thickness of each layer of the paint replacement film A paint substitute film was cut to a length of 2 mm in the flow direction and 2 cm in the width direction, fixed in an embedding capsule, and then embedded in epoxy resin. The embedded sample was then cut perpendicular to the width direction using a microtome (Reichert-Jung Supercut) to obtain 50 μm thick thin film sections. Using a scanning electron microscope (Hitachi 4300SE / N), the sections were observed and photographed at an accelerating voltage of 20 kV, and the thickness of each layer was measured from the photographs. The average thickness of five points was then calculated.

[0078] (D) Surface orientation coefficient According to JIS K 7142-1996 Method A, the refractive index in the flow direction (Nx), the refractive index in the width direction (Ny), and the refractive index in the thickness direction (Nz) of the substrate film were measured using an Abbe refractometer with sodium D line as the light source, and the surface orientation coefficient ΔP was calculated using the formula in Equation 2 below. Equation 2: Planar orientation coefficient ΔP = (Nx + Ny) / 2 - Nz

[0079] (E) Thermal shrinkage rate Test specimens were prepared by cutting five pieces each from the flow direction and width direction of the base film, with dimensions of 10 mm in width and 150 mm in length. Each test specimen was marked with gauge lines spaced 100 mm ± 2 mm apart, centered on the center of the specimen. The spacing of the gauge lines on the test specimens before heating was measured with an accuracy of 0.1 mm. The test specimens were suspended without load in a hot air dryer (ESPEC PHH-202) and heat-treated at 150°C for 15 minutes. After removing the test specimens from the constant temperature bath and cooling to room temperature, the length and width were measured at the same points as when they were first measured. The thermal shrinkage rate, i.e., the dimensional change rate, of each test specimen was calculated as a percentage of the initial dimensional change in the flow direction and width direction. The dimensional change rate in each direction was the average of the measured values ​​in that direction. In other words, the thermal contraction rate in each direction was calculated using the following formula. Thermal shrinkage rate (%) = {(L0 - L) / L0} × 100 Here, L is the gauge length after heat treatment (i.e., the distance between a pair of gauge marks), and L0 is the gauge length before heat treatment. As mentioned above, the average values ​​of the five test specimens were substituted for L and L0.

[0080] (F) Elastic strain energy In accordance with JIS K 7127, test samples of 15 mm width and 100 mm length were cut from the base film in both the flow direction and the width direction. Tensile tests were performed using a tensile testing machine (Shimadzu Corporation Autograph AG-I) under the following conditions: a chuck distance of 50 mm, a tensile speed of 1000 mm / min, and pulling until 20% elongation, followed by returning to a chuck distance of 50 mm at a speed of 2000 mm / min. The tensile tests were conducted in a constant temperature chamber at 100°C. From the obtained stress-strain curves, the stress at 20% elongation (F20 value) of the test sample, and the elastic strain energy Ua from the test start point (0) to the yield point, and the elastic strain energy Ub of the return strain from 20% elongation to a chuck distance of 50 mm were calculated using equations 3 and 4.

[0081] [Formula 3]

number

[0082] [Formula 4]

number

[0083] Here, as shown in Figure 1, a represents the strain (%) at the yield point, and P1 represents the stress (MPa) at the yield point. b represents the strain (%) at which the stress becomes 0 MPa after 20% elongation, i.e., the rebound strain (%). P2 represents the stress (MPa) at 20% elongation. P represents stress. λ represents strain (%). Furthermore, the yield point was determined by finding the first stress at which the stress increase per 0.3% increase in strain was 0.010 MPa or less in the stress-strain curve. Specifically, the stress was first read from the stress-strain curve at each 0.3% increase in strain, starting from 1.0%. That is, the stress was calculated at strains of 1.0%, 1.3%, 1.6%, 1.9%, 2.2%, 2.5%, 2.8%, 3.1%, and so on. Then, the yield point was determined by finding the first stress at which the stress increase per 0.3% increase in strain was 0.010 MPa or less.

[0084] (G) Evaluation of adhesion after hot press molding The second adhesive layer side of the paint substitute film was heat-pressed to a polypropylene (PP) resin sheet with a thickness of 2.0 mm heated to 130°C. The resulting film-coated resin laminate was cut to a size of 200 mm in width and 200 mm in length, and then hot-pressed. This hot-pressing was performed so that the partial elongation of the paint substitute film in the film-coated resin laminate (i.e., the laminate including the PP resin sheet and the paint substitute film laminated on the PP resin sheet) was approximately 20%. The adhesive strength of the bonded portion of the paint substitute film to this molded product was visually determined as follows. Judgment A: No peeling Assessment B: Partial peeling present (some air bubbles present) Assessment C: Complete detachment present

[0085] (H) Evaluation of moldability after hot press molding The moldability of the molded product after the hot-press molding process described above was visually assessed as follows. Condition A: No cracks or tears. Assessment B: No cracks or tears, but there are pinholes. Assessment C: At least one of the following is present: cracks and / or tears.

[0086] (I) Evaluation of image clarity after hot press molding The molded product after hot-press molding was placed 50 cm away from directly below a fluorescent light at a height of 2.5 m, with the surface protective layer of the molded product facing upwards. In other words, the molded product was placed 50 cm away from directly below the fluorescent light so that the surface protective layer of the molded product was facing upwards. Next, the image of the fluorescent light reflected onto the molded product was visually observed from a position where the image of the fluorescent light was visible, and judged according to the following criteria. Judgment A: The image of the fluorescent light shows almost no distortion. Judgment B: The image of the fluorescent light is partially distorted. Rating C: The image of the fluorescent light is distorted overall.

[0087] In the examples and comparative examples, the following resins were used as the resin constituting the B layer of the base film (i.e., laminated film).

[0088] (Resin composition A) A mixture of resins B and C was used as resin composition A. Resin B: PET resin, IV = 0.75 dl / g, melting point 255°C, 97.0 parts by mass Resin C: PET resin containing 0.036% by mass of silica particles (average particle size 1.7 μm) per 100% by mass of resin, IV = 0.75 dl / g, melting point 255°C, 3.0 parts by mass

[0089] (Resin composition D) A mixture of the following resins E and F was used as resin composition D. Resin E: PET resin, IV = 0.62 dl / g, melting point 255°C, 90.0 parts by mass Resin F: PET resin containing 0.72% by mass of silica particles (average particle size 2.7 μm) per 100% by mass of resin, IV = 0.62 dl / g, melting point 255°C, 10.0 parts by mass

[0090] (Resin composition G) PET resin, IV = 0.69 dl / g, melting point 225°C, 100.0 parts by mass

[0091] (Resin composition H) A mixture of the following resins I and J was used as the resin composition H. Resin I: Copolymer polyester resin containing 89.2 mol% ethylene terephthalate units and 10.8 mol% ethylene isophthalate units, IV = 0.71 dl / g, melting point 225°C, 55.0 parts by mass Resin J: PBT resin, IV = 0.67 dl / g, melting point 225°C, 45.0 parts by mass

[0092] In the examples and comparative examples, the following resins were used as the resin constituting layer A of the base film (i.e., laminated film). (Resin K) Copolymer polyester resin containing 89.2 mol% ethylene terephthalate units and 10.8 mol% ethylene isophthalate units, IV = 0.63 dl / g, melting point 225°C (Resin L) Copolymer polyester resin containing 86.0 mol% ethylene terephthalate units and 14.0 mol% ethylene isophthalate units, IV = 0.70 dl / g, melting point 217°C (Resin M) Copolymer polyester resin containing 80.0 mol% ethylene terephthalate units and 20.0 mol% ethylene isophthalate units, IV = 0.63 dl / g, melting point 198°C (Resin N) Copolymer polyester resin containing 92.1 mol% ethylene terephthalate units and 7.9 mol% ethylene isophthalate units, IV = 0.62 dl / g, melting point 233°C

[0093] (Hard coat paint) In the examples and comparative examples, the following hard coat coatings were prepared as resin compositions for forming the surface protective layer.

[0094] 150 parts by mass of methyl isobutyl ketone were placed in a four-necked flask equipped with a condenser, stirrer, thermometer, and nitrogen inlet tube, and the mixture was heated while stirring under a nitrogen atmosphere. When the temperature in the flask reached 74°C, this temperature was maintained as the synthesis temperature, and a monomer solution consisting of 3 parts by mass of methyl methacrylate, 82.54 parts by mass of n-butyl methacrylate, 12.85 parts by mass of 4-hydroxybutyl acrylate, 0.61 parts by mass of methacrylic acid, 1 part by mass of Funcryl FA-711MM (manufactured by Hitachi Chemical Co., Ltd., pentamethylpiperidinyl methacrylate), and 0.1 parts by mass of azobisisobutyronitrile was added dropwise to the flask over 2 hours. Starting 1 hour after the end of monomer addition, 0.02 parts by mass of azobisisobutyronitrile were added every hour to continue the reaction until the amount of unreacted monomer in the monomer solution was 1% or less. When the amount of unreacted monomer was reduced to 1% or less, the reaction was terminated by cooling, yielding an acrylic copolymer solution with a solid content of approximately 40% by mass. To this acrylic copolymer solution, 59.9 parts by mass (solid mass) of Duranate "P301-75E" (manufactured by Asahi Kasei Chemicals, a polyisocyanate variant of hexamethylene diisocyanate) was added as a polyisocyanate compound, and then methyl isobutyl ketone was added to bring the solid content to 30% by mass, and the mixture was stirred to obtain a hard coat coating.

[0095] [Example 1] Resin composition A for layer B and resin K for layer A were supplied to separate hoppers. Both layers A and B were melted at 280°C, then merged into two layers in a die, and extruded into a cooling drum to form an unstretched sheet. Subsequently, the unstretched sheet was stretched 3.2 times in the flow direction at 80°C, and then stretched 3.0 times in the width direction at 130°C. After heat setting at 215°C, a 5% relaxation process was performed in the width direction. In this way, a base film consisting of two layers, layer A and layer B, was produced with a thickness of 10 μm for layer A, a thickness of 40 μm for layer B, and a total thickness of 50 μm.

[0096] The first and second adhesive layers were formed during the film formation of the base film by in-line coating, applying a first adhesive having epoxy groups to the B-layer side surface and a second adhesive made of polyolefin resin to the A-layer side surface.

[0097] Next, the base film was unwound, and the colored layer was first coated using a comma coater. The colored layer used a solvent paint containing 10% by mass of acrylic urethane resin and aluminum pigment as binder components, and 35% by mass of non-volatile components. The coating was applied to a thickness of 20 μm, dried in a 90°C drying oven, and then wound up.

[0098] The resulting raw material, having the first adhesive layer, the second adhesive layer, and the colored layer, was unrolled, and the aforementioned hard coat coating was applied to the colored layer using a comma coater to a hard coat layer thickness of 30 μm as a surface protective layer, and then thoroughly dried in a drying oven at 90°C. At this time, the hard coat layer constituting the paint substitute film was in a semi-cured state, that is, in an incomplete state of heat curing.

[0099] Next, a 47 μm thick, delaminated, biaxially oriented polyethylene terephthalate resin film copolymerized with isophthalic acid was used as a protective film and laminated onto the hard coat layer. This was then wound into a roll to obtain a paint substitute film.

[0100] [Example 2] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that it was stretched 3.9 times in the flow direction and 3.5 times in the width direction. A coating substitute film was then prepared in the same manner as in Example 1.

[0101] [Example 3] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin composition D was used as the resin for layer B, and it was stretched 3.5 times in the flow direction and 3.3 times in the width direction. A coating substitute film was then prepared in the same manner as in Example 1.

[0102] [Comparative Example 1] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin L was used as the resin for layer A, and it was stretched 3.0 times in the flow direction and 3.5 times in the width direction. A paint substitute film was then prepared in the same manner as in Example 1.

[0103] [Comparative Example 2] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin composition D was used as the resin for layer B, and it was stretched 3.5 times in the flow direction and 3.3 times in the width direction, with a heat setting temperature of 235°C. A coating substitute film was then prepared in the same manner as in Example 1.

[0104] [Comparative Example 3] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin composition D was used as the resin for layer B and resin L was used as the resin for layer A, and the film was stretched 3.8 times in the flow direction and 3.3 times in the width direction. A coating substitute film was then prepared in the same manner as in Example 1.

[0105] [Comparative Example 4] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin composition D was used as the resin for layer B and resin M was used as the resin for layer A, and the film was stretched 3.5 times in the flow direction and 3.3 times in the width direction. A coating substitute film was then prepared in the same manner as in Example 1.

[0106] [Example 4] A base film consisting of two layers, A and B, was prepared in the same manner as in Example 1, except that resin N was used as the resin for layer A, and it was stretched 3.0 times in the flow direction and 3.5 times in the width direction. A paint substitute film was then prepared in the same manner as in Example 1.

[0107] [Comparative Example 6] Resin composition H was used as the resin for layer B and layer A, and the film was stretched 3.0 times in the flow direction and 3.0 times in the width direction, with a heat-fixing temperature of 205°C. Except for these differences, a base film consisting of single layers of the same raw materials for both layer A and layer B was prepared in the same manner as in Example 1, and a coating substitute film was prepared in the same manner as in Example 1.

[0108] [Comparative Example 7] Resin composition G was used as the resin for layer B and layer A, and the film was stretched 3.1 times in the flow direction and 3.5 times in the width direction, with a heat-fixing temperature of 180°C. Except for these differences, a base film consisting of single layers of the same raw materials for both layer A and layer B was prepared in the same manner as in Example 1, and a coating substitute film was prepared in the same manner as in Example 1.

[0109] [Comparative Example 8] The coating substitute film was prepared in the same manner as in Example 1, except that the base film was prepared using the method described in Example 7 of Patent Document 2 (i.e., Japanese Patent Application Publication No. 2020-192787). The resin used for layer A and the manufacturing conditions such as the stretching ratio are as shown in Table 1C below.

[0110] Table 1 shows the composition of the coating substitute films prepared in Examples 1-4, Comparative Examples 1-4, and Comparative Examples 6-8.

[0111] [Table 1A]

[0112] [Table 1B]

[0113] [Table 1C]

[0114] The paint-alternative films prepared in Examples 1-4, Comparative Examples 1-4, and Comparative Examples 6-8 were used to evaluate the film properties, including the surface orientation coefficient, thermal shrinkage rate, and elastic strain energy. Adhesion, moldability, and image clarity after hot-press molding were also evaluated. The evaluation results are shown in Table 2.

[0115] [Table 2A]

[0116] [Table 2B]

[0117] [Table 2C]

[0118] As shown in Table 2, the paint substitute films prepared in the examples exhibited good adhesion, moldability, and image clarity. On the other hand, the paint substitute films prepared in the comparative examples showed inferiority in at least one of the following: adhesion, moldability, and image clarity, making them unsuitable as paint substitute films. In particular, the residual internal stress index rates in Comparative Examples 1-4, 6, and 7 were considerably higher than those in Examples 1-4, and the adhesion evaluation results in these comparative examples were inferior to those of Examples 1-4. Meanwhile, although the residual internal stress index rate in Comparative Example 8 was similar to that of Example 1, it exhibited significant thermal shrinkage (i.e., a high thermal shrinkage rate), and the paint substitute film of Comparative Example 8 partially peeled off the PP resin board. Incidentally, although the adhesion of both Comparative Example 8 and Comparative Example 3 was rated B, the adhesion of Comparative Example 8 was superior to that of Comparative Example 3. In other words, the adhesion of Comparative Example 8 was closer to A than that of Comparative Example 3. In the above examples (i.e., Examples 1-4 and Comparative Examples 1-4 and 6-8), a biaxially oriented polyethylene terephthalate resin film copolymerized with isophthalic acid was used as the protective film. When a coating substitute film identical to the above examples was prepared, except that a polyethylene film was used instead of the biaxially oriented polyethylene terephthalate resin film copolymerized with isophthalic acid, results similar to those of the molded product evaluation shown in Table 2 (specifically, Tables 2A, 2B, and 2C) were obtained.

Claims

1. A paint substitute film comprising, in this order, a surface protective layer, a coloring layer, a first adhesive layer, a laminated film, and a second adhesive layer, The laminated film includes layer A and layer B, The surface protective layer is laminated on the surface of the colored layer. The colored layer is laminated on the surface of the first adhesive layer. The first adhesive layer is laminated on the surface of the B layer, The second adhesive layer is laminated on the surface of the A layer, The aforementioned layer A contains 60% by mass or more of the first crystalline polyester in 100% by mass of the layer A, The aforementioned B layer contains 60% by mass or more of the second crystalline polyester in 100% by mass of the B layer. The surface orientation coefficient of the aforementioned B layer is 0.165 or more and 0.180 or less. The melting point of layer B is higher than the melting point of layer A, and the difference between the melting point of layer B and the melting point of layer A is 20°C or more and 35°C or less. When the laminated film was subjected to a tensile test, the residual internal stress index was 25% or less in both the flow direction and the width direction of the laminated film. The aforementioned remaining index rate is expressed by |1 - (Ub / Ua)| × 100, The tensile test described above was performed by gripping a 15 mm wide test specimen with a pair of chucks at a distance of 50 mm between the chucks, widening the distance between the chucks at a tensile speed of 1000 mm / min at 100°C until a 20% strain occurred, and then returning the distance between the chucks to 50 mm at a speed of 2000 mm / min at 100°C. The aforementioned Ua is a value obtained by integrating the stress-strain curve obtained from the tensile test from 0% strain to yield strain. The aforementioned Ub is a value obtained by integrating the stress-strain curve from 20% strain to the strain at which the stress is 0 MPa. Paint substitute film.

2. Includes a protective film, The protective film, the surface protective layer, the coloring layer, the first adhesive layer, the laminated film, and the second adhesive layer are arranged in this order. The paint substitute film according to claim 1.

3. The coating substitute film according to claim 1, wherein the laminated film has a 20% strain tensile stress of 60 MPa or more and 110 MPa or less in both the flow direction and the width direction of the tensile test.

4. The paint substitute film according to claim 1, wherein the surface orientation coefficient of layer B is greater than the surface orientation coefficient of layer A, and the difference between the surface orientation coefficient of layer B and the surface orientation coefficient of layer A is 0.03 or more.

5. The coating substitute film according to claim 1, wherein when the laminated film is heat-treated at 150°C for 15 minutes, the sum of the thermal shrinkage rate in the flow direction and the thermal shrinkage rate in the width direction is 1.0% or more and 5.0% or less.

6. The coating substitute film according to claim 1, wherein the first adhesive layer comprises a resin having at least one functional group selected from the group consisting of epoxy groups, oxazoline groups, silanol groups, and isocyanate groups.

7. The coating substitute film according to claim 1, wherein the thickness of the first adhesive layer is 10 nm to 200 nm.

8. The paint substitute film according to claim 1, wherein the colored layer contains 0.5% by mass or more and less than 40% by mass of a coloring agent based on 100% by mass of the resin composition constituting the colored layer.

9. The coating substitute film according to claim 1, wherein the surface protective layer comprises at least one of a thermosetting resin and a photocurable resin.

10. A resin plate and The resin plate is laminated with a coating substitute film according to any one of claims 1 to 9, The second adhesive layer is disposed between the resin plate and the laminated film. Laminated structure.

11. A molded article formed by molding the laminate according to claim 10.

12. A vehicle exterior component comprising the laminate described in claim 10.

13. The method includes pressing a resin plate and a paint substitute film according to any one of claims 1 to 9 together such that the second adhesive layer of the paint substitute film is in contact with the resin plate. A method for manufacturing laminates.

Images