Moisture-curable resin sheet, vehicle component, and vehicle

Abstract

This moisture-curable resin sheet of the present invention is provided with a transfer layer and a resin layer formed from a moisture-curable resin composition. The peel force (max. Fbf) when the transfer layer is peeled from the resin layer before being cured as measured with a prescribed measurement method is 2N / 25 mm or larger. A peeling force (ave. Faf) when the transfer layer is peeled from the resin layer after being cured as measured with the prescribed measurement method is 0.5 N / 25 mm or smaller. The vehicle component and the vehicle of the present invention each have a coating formed by using the moisture-curable resin sheet of the present invention. According to the present invention, it is possible to provide a moisture-curable resin sheet in which the occurrence of lifting between the transfer layer and the resin layer which arises when the resin layer before curing is applied to an adherend can be suppressed, and in which the transfer layer can be easily peeled off from the resin layer after curing, as well as the vehicle component and the vehicle each having a coating formed by using the moisture-curable resin sheet.

Description

Moisture-curable resin sheet, vehicle parts, and vehicle

[0001] The present invention relates to a moisture-curable resin sheet, a vehicle part having a coating formed of the moisture-curable resin sheet, and a vehicle.

[0002] Conventionally, coatings have been applied to various products such as furniture, steel plates, and vehicle bodies to impart functions such as design, durability, weather resistance, and scratch resistance. As the coating, it is generally performed by spraying with air or electrostatic force. In the coating by spraying, losses generated during coating, CO discharged from the factory

[0004] , and from the perspective of large-scale equipment investment, in recent years, replacement with a decoration technology using a resin film has been considered.

[0003] Decoration technology is a technology that expresses high functionality and design by attaching a resin film (decoration film) printed with characters or patterns with white, black, color ink, etc. to an adherend. As the decoration film, for example, a thermosetting resin and a thermosetting resin sheet containing a curing agent are known to be used. After the thermosetting resin sheet is bonded to the adherend, heating is performed to cure the thermosetting resin sheet, so that it can be coated on the adherend with high adhesive strength.

[0004] However, since the thermosetting resin sheet requires heating after bonding, it may not be applicable depending on the type of the adherend. Therefore, the use of a moisture-curable resin sheet as a decoration film has been considered. Generally, as the moisture-curable resin, for example, as disclosed in Patent Document 1, a moisture-curable urethane resin is widely used. Also, for example, as shown in Patent Document 2, it is also known that an acrylic skeleton is introduced into the urethane prepolymer used for the moisture-curable urethane resin.

[0005] Japanese Patent No. 7363124 Japanese Patent No. 6584382

[0006] Incidentally, decorative resin sheets (resin layers) are sometimes laminated on top of a transfer layer and then bonded to the substrate in order to facilitate adhesion. In this case, if the resin sheet bonded to the substrate is peeled off the transfer layer before curing and cured in an exposed state, foreign matter may adhere to it or it may get scratched. Therefore, in order to keep the surface of the resin layer smooth, it is desirable to cure the resin layer with the transfer layer still attached, and then peel off the transfer layer after the resin layer has cured.

[0007] However, when the resin sheet was bonded to the substrate with the transfer layer attached, lifting sometimes occurred between the transfer layer and the resin layer.

[0008] Therefore, the object of the present invention is to provide a moisture-curable resin sheet that can suppress the occurrence of lifting between the transfer layer and the resin layer when it is attached to an adherend before the resin layer hardens, and that allows for easy peeling of the transfer layer after the resin layer hardens, as well as vehicle parts and vehicles having a coating formed from the moisture-curable resin sheet.

[0009] As a result of diligent research, the inventors have found that the above problems can be solved by using a moisture-curable resin sheet in which the peeling force when peeling the transfer layer from the resin layer before curing and the peeling force when peeling the transfer layer from the resin layer after curing are within a predetermined range, and have completed the present invention as follows. That is, the present invention provides the following [1] to

[12] . [1] A moisture-curable resin sheet comprising a transfer layer and a resin layer made of a moisture-curable resin composition, wherein the peeling force (max. Fbf) when peeling the transfer layer from the resin layer before curing, measured by the measurement method below, is 2 N / 25 mm or more, and the peeling force (ave. Faf) when peeling the transfer layer from the resin layer after curing, measured by the measurement method below, is 0.5 N / 25 mm or less. [Peeling force when peeling the transfer layer from the resin layer before curing (max. Fbf)] (1) Expose the moisture-curable resin sheet at room temperature to an environment with room temperature and humidity of 5% RH or more and 50% RH or less. (2) Cut the moisture-curing resin sheet to a width of 25 mm and attach the resin layer side of the moisture-curing resin sheet to the SPCC-SD urethane coating test piece, which is a coated board, using a squeegee. (3) Within 3 hours of starting to expose the moisture-curing resin sheet to an environment of room temperature and humidity between 5% RH and 50% RH, and within 1 hour of attaching the moisture-curing resin sheet to the coated board, peel off the transfer layer from the moisture-curing resin sheet attached to the coated board at a measurement temperature of 25°C and a tensile speed of 300 mm / min, and perform a 180° peel test to measure the peel strength. (4) The maximum value of the peel strength at a sweep distance of 25 mm to 75 mm shall be defined as the peel force (max. Fbf). [Peel force (ave. Faf) when peeling the transfer layer from the cured resin layer] (1) Expose the moisture-curing resin sheet to an environment of room temperature and humidity of 50% RH for one month. (2) Cut the moisture-curing resin sheet to a width of 25 mm and attach the resin layer side of the moisture-curing resin sheet to the SPCC-SD urethane coating test piece, which is a coated plate, using double-sided tape. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, peel off the transfer layer from the moisture-curing resin sheet attached to the coated plate and perform a 180° peel test to measure the peel strength. (4) The average value of the peel strength over a sweep distance of 25 mm to 75 mm is defined as the peel force (ave. Faf).[2] The moisture-curable resin sheet according to [1], wherein the peel force (max. Fbf) when peeling the transfer layer from the resin layer before curing is 5 N / 25 mm or more. [3] The moisture-curable resin sheet according to [1] or [2], wherein the peel force (ave. Faf) when peeling the transfer layer from the resin layer after curing is 0.25 N / 25 mm or less. [4] The moisture-curable resin sheet according to any one of [1] to [3], wherein the moisture-curable resin composition comprises a (meth)acrylic resin (A) having isocyanate groups. [5] The moisture-curable resin sheet according to [4], wherein the weight-average molecular weight of the (meth)acrylic resin (A) is 10,000 or more and 200,000 or less. [6] The moisture-curable resin sheet according to [4] or [5], further comprising a compound (B) having a plurality of isocyanate groups other than the (meth)acrylic resin (A). [7] The moisture-curing resin sheet according to [6], wherein the compound (B) has a molecular weight of 2000 or less. [8] The moisture-curing resin sheet according to any one of [4] to [7], wherein the content of the (meth)acrylic resin (A) in the moisture-curing resin composition is 30% by mass or more. [9] The moisture-curing resin sheet according to [8], wherein the content of the (meth)acrylic resin (A) in the moisture-curing resin composition is 65% by mass or more and 92% by mass or less.

[10] The moisture-curing resin sheet according to any one of [4] to [9], wherein the (meth)acrylic resin (A) has an isocyanate group in its side chain.

[11] A vehicle part having a coating formed from the moisture-curing resin sheet according to any one of [1] to

[10] .

[12] A vehicle having a coating formed from the moisture-curing resin sheet according to any one of [1] to

[10] .

[0010] According to the present invention, it is possible to provide a moisture-curable resin sheet that can suppress the occurrence of lifting between the transfer layer and the resin layer when it is attached to an adherend before the resin layer hardens, and that allows for easy peeling of the transfer layer after the resin layer hardens, as well as vehicle parts and vehicles having a coating formed from the moisture-curable resin sheet.

[0011] This is a schematic cross-sectional view showing one embodiment of a moisture-curing resin sheet.

[0012] <Moisture-curing resin sheet> The moisture-curing resin sheet of the present invention will be described below with reference to embodiments. As shown in Figures 1 and 2, the moisture-curing resin sheet 10 comprises a resin layer 11 made of a moisture-curing resin composition and a transfer layer 12, with the transfer layer 12 laminated on one side of the resin layer 11. The moisture-curing resin sheet 10 may consist of a resin layer 11 and a transfer layer 12 as shown in Figure 1, but it may also further include a protective layer 13 as shown in Figure 2, and the protective layer 13 is preferably laminated on the side of the resin layer 11 opposite to the side on which the transfer layer 12 is provided. The moisture-curing resin sheet will be described in detail below.

[0013] [Peeling Force] The moisture-curable resin sheet of the present invention has a peeling force (max. Fbf) of 2 N / 25 mm or more when peeling the transfer layer from the uncured resin layer, as measured by the following measurement method, and a peeling force (ave. Faf) of 0.5 N / 25 mm or less when peeling the transfer layer from the cured resin layer, as measured by the following measurement method. [Peeling force (max. Fbf) when peeling the transfer layer from the uncured resin layer] (1) Expose the moisture-curable resin sheet at room temperature to an environment of room temperature (23°C ± 2°C) and humidity of 5% RH or more and 50% RH or less. Here, "expose the moisture-curable resin sheet at room temperature to an environment of room temperature and humidity of 5% RH or more and 50% RH or less" means that the moisture-curable resin sheet itself is at room temperature and placed in an environment of room temperature and humidity of 5% RH or more and 50% RH or less. (2) Cut the moisture-curing resin sheet to a width of 25 mm and attach the resin layer side of the moisture-curing resin sheet to the SPCC-SD urethane coating test piece, which is a coated board, using a squeegee. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, peel off the transfer layer from the moisture-curing resin sheet attached to the coated board and perform a 180° peel test to measure the peel strength. Note that the above peel strength measurement should be performed within 3 hours from the start of exposure of the moisture-curing resin sheet to a room temperature and humidity of 5% RH to 50% RH, and within 1 hour from the time the moisture-curing resin sheet is attached to the coated board. (4) The maximum value of the peel strength at a sweep distance of 25 mm to 75 mm shall be defined as the peel force (max. Fbf). [Peel force (ave. Faf) when peeling the transfer layer from the cured resin layer] (1) Expose the moisture-curing resin sheet to a room temperature and humidity of 50% RH for one month. (2) Cut the moisture-curing resin sheet to a width of 25 mm and attach the resin layer side of the moisture-curing resin sheet to the SPCC-SD urethane coating test piece, which is a coated plate, using double-sided tape. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, peel off the transfer layer from the moisture-curing resin sheet attached to the coated plate at a sweep distance of 25 mm to 75 mm and perform a 180° peel test to measure the peel strength. (4) The average value of the peel strength at a sweep distance of 25 mm to 75 mm is defined as the peel force (ave. Faf).Note that a moisture-curing resin sheet at room temperature refers to a moisture-curing resin sheet at room temperature (23°C ± 2°C). If the moisture-curing resin sheet is not at room temperature, it must be brought to room temperature before being exposed to an environment with room temperature and humidity between 5% RH and 50% RH. For example, in the case of a moisture-curing resin sheet stored in an aluminum pouch in a frozen state (e.g., -20°C), the frozen moisture-curing resin sheet is removed from the freezing state, and after it has reached room temperature, the aluminum pouch is opened and the moisture-curing resin sheet is removed from the aluminum pouch. Then, the moisture-curing resin sheet at room temperature is exposed to an environment with room temperature and humidity between 5% RH and 50% RH. Furthermore, in the case of moisture-curing resin sheets stored in an aluminum pouch at room temperature, the aluminum pouch is opened and the moisture-curing resin sheet is removed from the pouch and exposed to an environment at room temperature with a humidity of 5% RH to 50% RH. Examples of aluminum pouches include the product name "Lamizip Stand Type Aluminum" (manufactured by Seisan Nippon Co., Ltd.). In the case of moisture-curing resin sheets in a frozen state (e.g., -20°C), the moisture-curing resin sheet is removed from the frozen state, and after the moisture-curing resin sheet has reached room temperature, that is, after the moisture-curing resin sheet has reached room temperature, it is exposed to an environment at room temperature with a humidity of 5% RH to 50% RH. For the painted board, for example, an SPCC-SD urethane painted test piece manufactured by Standard Test Piece Co., Ltd. can be used. Furthermore, the length of the moisture-curing resin sheet to be attached to the painted board is not particularly limited as long as it is 100 mm or more.

[0014] As described above, the peel force (max. Fbf) when peeling the transfer layer from the uncured resin layer is 2 N / 25 mm or more. If the peel force (max. Fbf) when peeling the transfer layer from the uncured resin layer is less than 2 N / 25 mm, when a moisture-curable resin sheet is attached to an adherend before the resin layer has cured, lifting or peeling may occur between the transfer layer and the resin layer. From this viewpoint, the peel force (max. Fbf) is preferably 5 N / 25 mm or more, more preferably 10 N / 25 mm or more, and even more preferably 12 N / 25 mm or more. The upper limit of the range of the peel force (max. Fbf) is not particularly limited, but is usually 50 N / 25 mm, preferably 40 N / 25 mm, and more preferably 30 N / 25 mm. From this viewpoint, the peel force (max. Fbf) is preferably 2 N / 25 mm to 50 N / 25 mm, more preferably 2 N / 25 mm to 40 N / 25 mm, even more preferably 5 N / 25 mm to 40 N / 25 mm, even more preferably 10 N / 25 mm to 40 N / 25 mm, and even more preferably 12 N / 25 mm to 30 N / 25 mm. The peel force (max. Fbf) can be adjusted by the type of resin contained in the moisture-curable resin composition, the glass transition temperature, molecular weight and isocyanate group content, the resin constituting the transfer layer, the thickness of the transfer layer, the type of release layer formed on the surface of the transfer layer, etc.

[0015] As described above, the peel force (ave. Faf) when peeling the transfer layer from the cured resin layer is 0.5 N / 25 mm or less. If the peel force (ave. Faf) when peeling the transfer layer from the cured resin layer is greater than 0.5 N / 25 mm, peeling the transfer layer after the resin layer has cured may be difficult, or the resin layer may be damaged when peeling the transfer layer. From this viewpoint, the peel force (ave. Faf) is preferably 0.25 N / 25 mm or less, more preferably 0.15 N / 25 mm or less, and even more preferably 0.10 N / 25 mm or less. The lower limit of the range of the peel force (ave. Faf) is not particularly limited, but is usually 0.001 N / 25 mm. From this viewpoint, the peel force (ave. Faf) is preferably 0.001 N / 25 mm or more and 0.5 N / 25 mm or less, more preferably 0.001 N / 25 mm or more and 0.25 N / 25 mm or less, even more preferably 0.001 N / 25 mm or more and 0.15 N / 25 mm or less, and even more preferably 0.001 N / 25 mm or more and 0.10 N / 25 mm or less. The peel force (ave. Faf) can be adjusted by the type of resin contained in the moisture-curable resin composition, molecular weight and isocyanate group content, the resin constituting the transfer layer, the thickness of the transfer layer, the type of release layer formed on the surface of the transfer layer, etc.

[0016] [Resin Layer] The resin layer in the moisture-curable resin sheet of the present invention is made of a moisture-curable resin composition. The moisture-curable resin composition preferably contains (meth)acrylic resin (A) having isocyanate groups. By containing (meth)acrylic resin (A) having isocyanate groups, the moisture-curable resin composition can form a hardened layer that is tough, hard, has good surface gloss, excellent weather resistance, and allows for vivid coloring, through reaction with moisture.

[0017] ((meth)acrylic resin (A)) (meth)acrylic resin (A) is a moisture-curable resin having isocyanate groups and curing in reaction with moisture. (meth)acrylic resin (A) preferably has isocyanate groups in its side chains. Furthermore, (meth)acrylic resin (A) may have two or more isocyanate groups in one molecule. (meth)acrylic resin (A) is not particularly limited as long as it has isocyanate groups, but it is preferable to use (meth)acrylate having isocyanate groups as a raw material. Therefore, it is preferable that (meth)acrylic resin (A) is a polymer containing constituent units derived from (meth)acrylate having isocyanate groups.

[0018] The (meth)acrylate having isocyanate groups used as a raw material is preferably such that the (meth)acrylate portion of the compound constitutes the main chain in the polymer, and the isocyanate groups are positioned in the side chains of the polymer. In one molecule of (meth)acrylic resin (A), it is preferable that multiple isocyanate groups are contained in the side chains. Furthermore, (meth)acrylic resin (A) may or may not have isocyanate groups at its termini. In this specification, (meth)acrylate is used as a term meaning either acrylate or methacrylate, or both, and the same applies to other similar terms.

[0019] The (meth)acrylic resin (A) is a polymer obtained by polymerizing monomer (a) containing (meth)acrylate, and may have constituent units derived from (meth)acrylate in its main chain, but is preferably a polymer obtained by polymerizing monomer (a) containing (meth)acrylate having an isocyanate group, and is more preferably a polymer obtained by polymerizing monomer (a) containing (meth)acrylate having an isocyanate group and alkyl (meth)acrylate. Using alkyl (meth)acrylate can impart tackiness to the resin layer before curing. Furthermore, monomer (a) may also contain monomers other than (meth)acrylate and alkyl (meth)acrylate having an isocyanate group (other monomers).

[0020] Examples of (meth)acrylates having an isocyanate group include isocyanatoalkyl (meth)acrylates such as 2-isocyanatoethyl (meth)acrylate, 4-isocyanatobutyl (meth)acrylate, and 6-isocyanatohexyl (meth)acrylate, as well as 2-(2-isocyanatoethoxy)ethyl (meth)acrylate and 1,1-bis(acryloyloxymethyl)ethyl isocyanate, among which isocyanatoalkyl (meth)acrylate is preferred. The number of carbon atoms in the alkyl group in isocyanatoalkyl (meth)acrylate is not particularly limited, but is, for example, about 1 to 10, preferably 2 to 4.

[0021] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, isomiristyl (meth)acrylate, and stearyl (meth)acrylate, which have approximately 1 to 18 carbon atoms in the alkyl group. From the viewpoint of imparting tackiness to the resin layer before curing, the alkyl (meth)acrylate is preferably one in which the alkyl group has 1 to 12 carbon atoms. Furthermore, from the viewpoint of improving tackiness before curing, the alkyl (meth)acrylate is more preferably one in which the alkyl group has 3 to 10 carbon atoms.

[0022] Other monomers besides (meth)acrylates and alkyl (meth)acrylates having isocyanate groups include alicyclic (meth)acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, aromatic ring (meth)acrylates such as benzyl (meth)acrylate and phenoxydiethylene glycol (meth)acrylate, styrene monomers such as styrene, α-methylstyrene, α-ethylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-ethoxystyrene, p-chlorostyrene, m-chlorostyrene, and o-chlorostyrene, and vinyl monomers having vinyl ester groups such as vinyl acetate and vinyl propionate.

[0023] The amount of (meth)acrylate having an isocyanate group used in the monomer (a) constituting the (meth)acrylic resin (A) is preferably 2 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 25 mol% or less, preferably 2 mol% or more and 40 mol% or less, more preferably 5 mol% or more and 30 mol% or less, and even more preferably 8 mol% or more and 25 mol% or less. By setting the amount of (meth)acrylate having an isocyanate group used within the above range, it becomes even easier to increase the peeling force when peeling the transfer layer from the resin layer before curing and to decrease the peeling force when peeling the transfer layer from the resin layer after curing.

[0024] Furthermore, the amount of alkyl (meth)acrylate used in monomer (a) is preferably 50 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, preferably 98 mol% or less, more preferably 95 mol% or less, even more preferably 92 mol% or less, preferably 50 mol% or more and 98 mol% or less, more preferably 65 mol% or more and 95 mol% or less, and even more preferably 70 mol% or more and 92 mol% or less. By setting the amount of alkyl (meth)acrylate used to above the lower limit, flexibility is increased and it becomes easier to improve the adhesive strength before curing. Also, by setting it to below the upper limit, it becomes easier to include a certain amount or more of isocyanate groups, and it becomes easier to improve the adhesive strength and hardness after curing.

[0025] In monomer (a), the alkyl (meth)acrylate is particularly preferably an alkyl acrylate having 3 to 10 carbon atoms in the alkyl group, from the viewpoint of increasing flexibility and improving adhesion before curing. The amount of alkyl acrylate having 3 to 10 carbon atoms in the alkyl group in monomer (a) is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, preferably 98 mol% or less, more preferably 95 mol% or less, even more preferably 90 mol% or less, preferably 30 mol% or more and 98 mol% or less, more preferably 35 mol% or more and 95 mol% or less, and even more preferably 40 mol% or more and 90 mol% or less.

[0026] The weight-average molecular weight of (meth)acrylic resin (A) is preferably 10,000 or more and 200,000 or less. By setting the weight-average molecular weight of (meth)acrylic resin (A) within the above range, it becomes even easier to set the peel force (max. Fbf) to 2 N / 25 mm or more and the peel force (ave. Faf) to 0.5 N / 25 mm or less. Furthermore, by setting the weight-average molecular weight of (meth)acrylic resin (A) within the above range, it becomes easier to achieve a good balance of properties such as coatability, curability, tackiness, and extensibility of the moisture-curable resin composition. The weight-average molecular weight of (meth)acrylic resin (A) is more preferably 20,000 or more, even more preferably 40,000 or more, even more preferably 150,000 or less, even more preferably 100,000 or less, even more preferably 20,000 to 150,000, and even more preferably 40,000 to 100,000. In this specification, the weight-average molecular weight is measured by gel permeation chromatography (GPC) and is determined as a standard polystyrene equivalent value.

[0027] The content of (meth)acrylic resin (A) in the moisture-curable resin composition may be, for example, 20% by mass or more, but is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, even more preferably 60% by mass or more, and even more preferably 65% ​​by mass or more. By setting the content of (meth)acrylic resin (A) to a certain amount or more, it becomes even easier to set the peel force (max. Fbf) to 2 N / 25 mm or more and the peel force (ave. Faf) to 0.5 N / 25 mm or less. The content of (meth)acrylic resin (A) in the moisture-curable resin composition may be 100% by mass or less, but from the viewpoint of including a certain amount or more of other components such as compound (B), it is preferably 95% by mass or less, more preferably 92% by mass or less, even more preferably 90% by mass or less, even more preferably 85% by mass or less, and even more preferably 80% by mass or less. From this viewpoint, the content of (meth)acrylic resin (A) in the moisture-curing resin composition may be 20% by mass or more and 100% by mass or less, but is preferably 30% by mass or more and 95% by mass or less, more preferably 40% by mass or more and 92% by mass or less, even more preferably 50% by mass or more and 90% by mass or less, even more preferably 55% by mass or more and 85% by mass or less, even more preferably 60% by mass or more and 80% by mass or less, and even more preferably 65% ​​by mass or more and 80% by mass or less. By setting the content of (meth)acrylic resin (A) within the above range, it becomes even easier to set the peel force (max. Fbf) to 2 N / 25 mm or more and the peel force (ave. Faf) to 0.5 N / 25 mm or less. The content of (meth)acrylic resin (A) can be measured in accordance with JIS K7301:1995.

[0028] (Compound (B)) The moisture-curable resin sheet preferably further contains compound (B) (polyisocyanate compound) having isocyanate groups in addition to (meth)acrylic resin (A). By containing compound (B), the moisture-curable resin sheet can reduce the peeling force when peeling the transfer layer from the cured resin layer. Furthermore, by containing compound (B), the moisture-curable resin sheet can increase the hardness of the cured resin layer, thereby improving the mechanical strength and scratch resistance of the cured resin layer. Compound (B) preferably has two or more isocyanate groups. Also, compound (B) is preferably a compound other than the (meth)acrylic resin (A) described above and does not contain a polyacrylic skeleton.

[0029] Examples of compound (B) include aliphatic diisocyanate compounds such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, isophorone diisocyanate (IPDI), xylylene diisocyanate, hydrogenated xylylene diisocyanate (H6XDI), hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanate-methyl)cyclohexane, and dicyclohexylmethane diisocyanate, as well as aromatic diisocyanate compounds such as 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, and naphthalene-1,5-diisocyanate, and urethane prepolymers.

[0030] Compound (B) may be a modified product of the above polyisocyanate with a large amount added, such as polymeric MDI, or a polyol modified product of polyisocyanate (adduct), such as a trimethylolpropane adduct of polyisocyanate, a biuret, an allophanate, an isocyanurate, or a condensate thereof. Preferred specific examples include HDI adduct, HDI biuret, HDI allophanate, HDI isocyanurate, H6XDI isocyanurate, IPDI isocyanurate, and IPDI adduct. As compound (B), it is preferable to select one that is flexible and highly adhesive in its uncured state. From this viewpoint, aliphatic polyisocyanates or modified thereof are preferred, and among these, adducts, biuretes, allophanates, and isocyanurates of aliphatic polyisocyanates are more preferred, and adducts, biuretes, allophanates, and isocyanurates of HDI and IPDI are even more preferred. Compound (B) may be used alone or in combination of two or more.

[0031] The molecular weight of compound (B) is not particularly limited, but is preferably 2000 or less. Lowering the molecular weight of compound (B) makes it even easier to achieve the above peeling force (max. Fbf) of 2 N / 25 mm or more. The molecular weight of compound (B) is preferably 1000 or less, and more preferably 800 or less. The lower limit of the molecular weight range of compound (B) is not particularly limited, but the molecular weight of compound (B) is preferably, for example, 200 or more, more preferably 300 or more, and even more preferably 400 or more. From this viewpoint, the molecular weight of compound (B) is preferably 200 to 2000, more preferably 300 to 1000, and even more preferably 400 to 800. Note that the molecular weight of compound (B) is calculated from the structural formula. Also, when two or more types of compound (B) are used in combination, it refers to the weight-average molecular weight.

[0032] When compound (B) is used, the content of compound (B) in the moisture-curable resin composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 13 parts by mass or more, when the total of (meth)acrylic resin (A) and compound (B) is 100 parts by mass. Setting the content of compound (B) to a certain amount or more makes it even easier to set the peel force (ave. Faf) to 0.5 N / 25 mm or less. Furthermore, the content of compound (B) may be, for example, 70 parts by mass or less, but is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less. From this viewpoint, the content of compound (B) is preferably 5 parts by mass or more and 70 parts by mass or less, more preferably 5 parts by mass or more and 50 parts by mass or less, even more preferably 10 parts by mass or more and 40 parts by mass or less, and even more preferably 13 parts by mass or more and 30 parts by mass or less, when the total of (meth)acrylic resin (A) and compound (B) is 100 parts by mass. By keeping the content of compound (B) below a certain value, it becomes even easier to achieve the above-mentioned peeling force (max. Fbf) of 2 N / 25 mm or more.

[0033] (Moisture-curing accelerating catalyst) A moisture-curing resin composition may contain a moisture-curing accelerating catalyst that accelerates the moisture-curing reaction. By using a moisture-curing accelerating catalyst, the moisture-curing properties of the moisture-curing resin composition can be improved, and the hardness of the resin layer and the adhesive strength after curing can be increased. In addition, even when the outside temperature is low, such as in winter, it can be properly cured by leaving it in the atmosphere.Specific examples of moisture-curing accelerating catalysts include amine compounds and metal catalysts.Examples of amine compounds include compounds having a morpholine skeleton such as di(methylmorpholino)diethyl ether, 4-morpholinopropylmorpholine, and 2,2'-dimorpholinodiethyl ether; dimethylamino group-containing amine compounds having two dimethylamino groups, such as bis(2-dimethylaminoethyl) ether and 1,2-bis(dimethylamino)ethane; triethylamine, 1,4-diazabicyclo[2.2.2]octane, and 2,6,7-trimethyl-1,4-diazabicyclo[2.2.2]octane. Examples of metal catalysts include tin compounds such as di-n-butyltin dilaurate, di-n-butyltin diacetate, and tin octoate; zinc compounds such as zinc octoate and zinc naphthenate; and other metal compounds such as zirconium tetraacetylacetonate, copper naphthenate, and cobalt naphthenate. The content of the moisture curing accelerating catalyst in the moisture curing resin composition is preferably 0.001 parts by mass or more and 4 parts by mass or less, more preferably 0.01 parts by mass or more and 2 parts by mass or less, and even more preferably 0.1 parts by mass or more and 1 part by mass or less, based on 100 parts by mass of the total amount of (meth)acrylic resin (A) and compound (B).

[0034] (Surface modifier) ​​The moisture-curable resin composition may contain a surface modifier. The surface modifier adjusts the surface tension to improve wettability. Examples of surface modifiers include silicone-acrylic copolymers, silicones, polyacrylates, and fluorines. By including a surface modifier in the moisture-curable resin composition, the wettability of the moisture-curable resin composition can be improved, thereby improving the peel strength to the adherend. Furthermore, the smoothness and slipperiness of the surface can be adjusted to improve scratch resistance. The content of the surface modifier in the moisture-curable resin composition is preferably 0.01 parts by mass or more and 3 parts by mass or less, more preferably 0.05 parts by mass or more and 2 parts by mass or less, and even more preferably 0.1 parts by mass or more and 1 part by mass or less, based on 100 parts by mass of the total amount of (meth)acrylic resin (A) and compound (B).

[0035] (Coloring agent) The resin layer may be used, for example, for the protection or beautification of the adherend. Therefore, the moisture-curing resin composition may contain a coloring agent to form a colored layer. The coloring agent may be a pigment, a dye, or a glossing agent. Examples of pigments used as coloring agents include, but are not limited to, metal oxide pigments such as titanium dioxide and iron oxide, inorganic pigments such as carbon black, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, talc, silica, and alumina white, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, perylene pigments, perinone pigments, benzimidazolone pigments, vat pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, and indigo pigments. As dyes, known dyes can be used, including azo dyes, anthraquinone dyes, indigoid dyes, and stilbene dyes. The glossing agent is a compound that can impart glossiness to the resin layer and can impart the property of showing luster when observed from multiple directions. The glossing agent is not particularly limited, but examples include compounds in which a titanium oxide layer is provided on the surface of natural mica, synthetic mica, alumina flakes, glass flakes, etc. The content of the colorant in the moisture-curable resin composition is not particularly limited, but is preferably about 0.05% by mass or more and 15% by mass or less, more preferably 0.1% by mass or more and 12% by mass or less, and even more preferably 0.3% by mass or more and 8% by mass or less.

[0036] Furthermore, the resin layer may be a clear layer that substantially does not contain a coloring agent. The clear layer is a transparent layer and only needs to have enough transparency to allow the color of the colored layer to be visible from the outside through the clear layer, but it is preferable that the transmittance of light with a wavelength of 450 nm be 80% or more. The clear layer is preferably a resin layer that does not contain a coloring agent, but it may contain a small amount of a coloring agent as long as it does not impair its function. The amount of coloring agent in the clear layer is not particularly limited, but is, for example, 0% by mass or more, for example 2% by mass or less, preferably 0.5% by mass or less, more preferably 0.1% by mass or less, for example 0% by mass or more and 2% by mass or less, preferably 0% by mass or more and 0.5% by mass or less, and more preferably 0% by mass or more and 0.1% by mass or less.

[0037] Furthermore, the resin layer may be used to impart functions other than protection or beautification of the adherend, for example, as a heat-shielding coating. In this case, it is desirable that the coating formed by the resin layer functions as a heat-shielding coating, and in that case, the resin layer should contain a heat-shielding agent to form a heat-shielding layer. Also, by creating surface irregularities in the resin layer, surface properties such as matte or textured finishes can be imparted. In addition, functions such as rust prevention, mold prevention, heat insulation, and antistatic properties can also be achieved by incorporating components appropriate to the purpose (e.g., rust inhibitors, mold inhibitors, antistatic agents, etc.) into the resin layer.

[0038] The moisture-curing resin composition may contain components other than those described above, for example, other additives. Examples of additives include dehydrating agents, plasticizers, inorganic fillers other than colorants and heat shielding agents, dispersants, anti-aging agents, antioxidants, and ultraviolet absorbers. Furthermore, the moisture-curing resin composition may contain resin components other than components (A) and (B) above, as long as they do not impair the effects of the present invention.

[0039] The resin layer may consist of a single layer or have a multilayer structure of two or more layers, but a single layer structure is preferred. A single layer structure makes it easier to manufacture the resin layer. Furthermore, a multilayer structure allows various functions to be imparted to the coating formed from the resin layer. If the resin layer has a multilayer structure, at least the resin layer in contact with the transfer layer should contain each component as described above in the above-described amounts, but it is preferable that each layer be a resin layer as described above. In the case of a multilayer structure, the composition of each layer may be the same or different, but usually they are different.

[0040] In the case of a multilayer structure, the resin layer may include, for example, a colored layer containing a coloring agent and a clear layer substantially free of coloring agents, but it is preferable to include both a colored layer and a clear layer. When a colored layer and a clear layer are included, it is preferable that the clear layer and the colored layer be arranged in that order from the transfer layer side. With such a layer configuration, when the moisture-curable resin sheet is attached to the substrate, the colored layer and the clear layer will be arranged in that order from the substrate side. As described above, by having a colored layer, the substrate can be colored by the coating formed by the resin layer. In addition, by providing a clear layer in addition to the resin layer, the colored layer can be protected or a gloss can be given to the colored layer. In the multilayer structure, the colored layer only needs to have a coloring agent content within the above range, and similarly, the clear layer only needs to have a coloring agent content within the above range.

[0041] Of course, if the resin layer has a multilayer structure, it is not limited to a two-layer structure of a clear layer and a colored layer, but can have various laminated structures. It may have a structure of three or more layers by providing two or more colored layers and one or more clear layers, or it may consist of two colored layers by omitting the clear layer. It may also have two or more clear layers. Furthermore, a heat-shielding layer or the like may be provided between the clear layer and the colored layer to create a structure of three or more layers.

[0042] The thickness of the resin layer is not particularly limited, but is, for example, about 5 μm or more, preferably 15 μm or more, more preferably 20 μm or more, for example about 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less, for example about 5 μm to 1000 μm or less, preferably 15 μm to 500 μm or less, and more preferably 20 μm to 200 μm or less. Note that the thickness of the resin layer refers to the total thickness if the resin layer has a multilayer structure. Furthermore, if the resin layer is provided with a colored layer and a clear layer, the thickness of the colored layer is not particularly limited, but is, for example, 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, for example 500 μm or less, preferably 100 μm or less, more preferably 50 μm or less, for example 5 μm to 500 μm or less, preferably 10 μm to 100 μm or less, and more preferably 15 μm to 50 μm or less. Furthermore, the thickness of the clear layer is not particularly limited, but is, for example, 5 μm or more, preferably 10 μm or more, preferably 15 μm or more, for example 500 μm or less, preferably 100 μm or less, preferably 50 μm or less, for example 5 μm or more and 500 μm or less, preferably 10 μm or more and 100 μm or less, preferably 15 μm or more and 50 μm or less.

[0043] (Transfer Layer) The transfer layer is a component that protects the resin layer from scratches and the adhesion of foreign matter, and also serves as a support when the resin layer is attached to the substrate. The transfer layer is preferably formed from a resin film. The resin used in the resin film is preferably a thermoplastic resin, but other resins may also be used.Specific examples of resins used in the resin film include polyolefin resins such as cyclic polyolefin resins, polyethylene resins, and polypropylene resins, polyester resins such as ethylene vinyl acetate copolymer resins, polyethylene terephthalate, and polybutylene terephthalate, polyamide resins, acrylonitrile butadiene styrene resins, polycarbonate resins, acrylic resins, fluororesins, vinyl chloride resins, polymethylpentene resins, and tetrafluoroethylene resins. Among these resins, polyethylene resins, polypropylene resins, and polyethylene terephthalate are preferred, with polypropylene resin being preferred.

[0044] The resin film constituting the transfer layer may be a single-layer film consisting of one layer, or a multilayer film of two or more layers. Also, in the resin film constituting the transfer layer, the resin contained in the resin film may be used alone as one type, or two or more types may be used in combination. When two or more types of resins are used in combination, different types of resins may be used for each layer to form a multilayer film. Also, a single-layer film may be formed from a mixture of two or more resins, or one or more layers in a multilayer film may be formed. Also, the resin film used for the transfer layer may be a stretched resin film, or an unstretched resin film that has not been stretched.

[0045] The transfer layer may be a release film having a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent, and at least one surface thereof is subjected to a release treatment and provided with a release layer. Therefore, the transfer layer is preferably any one of a silicone-based release film, a long-chain alkyl-based release film, or a fluorine-based release film that has been subjected to a release treatment with a silicone-based release agent.

[0046] As described above, the transfer layer can adjust the releasability with respect to the resin layer by using a release film that has been subjected to a release treatment, and can appropriately adjust the release force before curing (max. Fbf) and the release force after curing (ave. Faf). Depending on the releasability, the release film is classified into a light release type, a medium release type, and a heavy release type, and it is advisable to appropriately select the type according to the composition of the resin layer. Also, the transfer layer may not be subjected to a release treatment as long as the release force before curing (max. Fbf) and the release force after curing (ave. Faf) can be within a desired range.

[0047] For the transfer layer, for example, by using a peelable film of the double-peel type, it is easier to increase the peel strength (max. Fbf). However, when using a peelable film of the double-peel type, the peel strength (ave. Faf) after curing also tends to be high. Therefore, it can be preferably used when the wettability to the resin layer is low and the peel strength after curing is not likely to increase, or when the adhesive strength of the resin layer is low. Also, for example, by using a peelable film of the light-peel type, the peel strength (max. Fbf) cannot be increased so much, but the peel strength (ave. Faf) after curing does not increase so much either. Therefore, it can be preferably used when the wettability to the resin layer is high or when the adhesive strength of the resin layer is relatively high. From the above viewpoints, for example, when using a (meth)acrylic resin (A) having an isocyanate group in a moisture-curable resin composition, it is preferable to use a silicone-based peelable film of the light-to-double-peel type, a long-chain alkyl-based or fluorine-based peelable film of the light-to-double-peel type, etc. Among them, it is more preferable to use a long-chain alkyl-based peelable film of the light-peel type and a fluorine-based peelable film of the light-peel type. Also, the transfer layer does not need to be subjected to a peeling treatment on the surface where the resin layer is laminated. The transfer layer may be laminated with the resin layer on a surface that has not been subjected to a peeling treatment, for example, a surface that has not been peeled.

[0048] The thickness of the transfer layer is not particularly limited. For example, it is 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, for example, 1000 μm or less, preferably 700 μm or less, more preferably 450 μm or less, even more preferably 200 μm or less, for example, 10 μm or more and 1000 μm or less, preferably 15 μm or more and 700 μm or less, more preferably 20 μm or more and 450 μm or less, even more preferably 30 μm or more and 200 μm or less. When the thickness of the transfer layer is within the above range, a certain strength and flexibility can be imparted to the transfer layer. Also, when the thickness of the transfer layer is within the above range, it becomes even easier to make the above peel strength (max. Fbf) 2 N / 25 mm or more and the above peel strength (ave. Faf) 0.5 N / 25 mm or less.

[0049] (Protective Layer) The protective layer is a component that protects the resin layer from scratches and the adhesion of foreign matter. The protective layer is preferably formed from a resin film. A thermoplastic resin is preferred as the resin used for the resin film of the protective layer, but other resins may also be used. Specific examples of the resin used for the resin film of the protective layer are the same as those listed for the resin used for the transfer layer. The resin used for the protective layer and the resin used for the transfer layer may be the same or different.

[0050] The resin film forming the protective layer may be a single-layer film consisting of one layer, or a multilayer film consisting of two or more layers. Furthermore, in the resin film constituting the protective layer, the resin contained in the resin film may be used alone, or two or more types may be used in combination. When two or more types of resin are used in combination, different types of resin may be used in each layer to form a multilayer film. Alternatively, a single-layer film may be formed by mixing two or more types of resin, or one or more layers in a multilayer film may be formed by mixing them. In addition, the resin film used for the protective layer may be a stretched resin film or an unstretched resin film.

[0051] The protective layer may have at least one surface that has been peeled off with a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent. When the protective layer is peeled off, it is preferable that the peeled surface constitutes the surface on the resin layer side. Peeling off the protective layer makes it easier to peel off from the resin layer. However, the protective layer does not need to be peeled off as long as it can be peeled off from the resin layer. The thickness of the protective layer is not particularly limited, but is, for example, 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, for example 1000 μm or less, preferably 700 μm or less, more preferably 500 μm or less, for example 10 μm or more and 1000 μm or less, preferably 15 μm or more and 700 μm or less, and more preferably 20 μm or more and 500 μm or less.

[0052] (Method for Manufacturing Moisture-Curing Resin Sheets) The method for manufacturing moisture-curing resin sheets is not particularly limited, but can be manufactured by known methods. For example, a moisture-curing resin composition may be prepared, the prepared moisture-curing resin composition may be applied to a transfer layer, and the resin layer may be formed by drying as necessary. The moisture-curing resin composition may contain (meth)acrylic resin (A), but may optionally contain compound (B), a surface modifier, a moisture-curing accelerating catalyst, a colorant, or other components. The details and content of each component in the moisture-curing resin composition are as described above for the resin layer. However, if the content standard was for the resin layer, the solid content of the moisture-curing resin composition excluding volatile matter may be used as the content standard instead.

[0053] Furthermore, if the moisture-curable resin sheet includes a protective layer, the moisture-curable resin composition may be applied to the protective layer and dried as necessary to form a resin layer, and a transfer layer may be further laminated onto the resin layer formed on the protective layer to obtain a moisture-curable resin sheet. When applying the moisture-curable resin composition to the transfer layer or protective layer, the moisture-curable resin composition may be appropriately diluted with a solvent or the like. Examples of solvents include ethyl acetate, butyl acetate, and toluene. The solvent may also be, for example, the solvent used in the production of (meth)acrylic resin (A).

[0054] Furthermore, if the resin layer is multilayered, it can be formed by sequentially forming and laminating each layer. For example, if it has a clear layer and a colored layer, the clear layer and the colored layer can be laminated on the transfer layer in that order. Also, if the moisture-curable resin sheet has a protective layer, a moisture-curable resin sheet can be obtained by laminating one or more resin layers formed on the protective layer with one or more resin layers formed on the transfer layer. In the case of multilayers, as described above, it is preferable that each layer consists of a moisture-curable resin composition containing the above-mentioned components in the above-mentioned amounts. The formulation of each layer may be the same or different, but usually they are different. It is preferable to form the resin layers in a low-humidity environment in order to prevent curing from progressing due to moisture absorption.

[0055] [Painting Method] The moisture-curing resin sheet of the present invention is suitable for use as a coating sheet. It is preferable to bond it to a substrate and then cure the resin layer to form a coating on the surface of the substrate consisting of a cured resin layer.

[0056] The following describes in detail one embodiment of a coating method for forming a coating on an adherend using the moisture-curing resin sheet of the present invention. The coating method according to one embodiment of the present invention comprises the following first, second, and third steps: First step: A step of attaching the moisture-curing resin sheet to the adherend. Second step: A step of curing the moisture-curing resin sheet. Third step: A step of peeling the transfer layer from the cured resin layer.

[0057] (First Step) The first step is to attach the moisture-curable resin sheet to the substrate. Before being attached to the substrate, the moisture-curable resin sheet may have a protective layer laminated on the side opposite to the side where the transfer layer of the resin layer is provided. If a protective layer is laminated, it is preferable to peel the protective layer from the resin layer before attaching the moisture-curable resin sheet to the substrate, exposing the resin layer, and then attaching it to the substrate. The method of peeling off the protective layer is not particularly limited and may be done by a peeling device or by hand. Of course, the protective layer may be omitted in the moisture-curable resin sheet.

[0058] In this process, a moisture-curable resin sheet with the resin layer exposed is preferably attached to the substrate so that the resin layer is in contact with it. The method of attaching the moisture-curable resin sheet to the substrate is not particularly limited; it may be done by hand or using a laminating device. Since the resin layer is made of a moisture-curable resin composition and is not yet cured at the time of attachment, it is easier to ensure a certain degree of flexibility. Therefore, the resin layer can adhere properly to the substrate and be temporarily fixed to it with appropriate adhesive force.

[0059] Alternatively, the moisture-curing resin sheet may be applied by a method known as wet application. Wet application is performed by first applying water to the substrate, then adhering the moisture-curing resin sheet to the water-coated surface, and finally using a squeegee or similar tool to push out the water between the moisture-curing resin sheet and the substrate. This pushes out any air bubbles or bubbles present between the moisture-curing resin sheet and the substrate along with the water, allowing the moisture-curing resin sheet to be neatly adhered to the substrate. The water applied to the substrate may be water alone, or additives such as surfactants or organic solvents may be added as appropriate.

[0060] The moisture-curing resin sheet may be pre-molded by vacuum forming, press forming, or compressed air forming, and shaped to correspond to the shape of the adherend. The shaped moisture-curing resin sheet is then attached to the adherend. Pre-molding may be performed before peeling off the protective layer from the resin layer, or after peeling off the protective layer, if the moisture-curing resin sheet has a protective layer. Pre-molding allows the moisture-curing resin sheet to be easily adhered to the adherend even if the adherend has a complex shape. Of the above methods, pre-molding is preferably performed by vacuum forming. Pre-molding is preferably performed by pressing the moisture-curing resin sheet against a jig or mold using vacuum forming, and then stretching the moisture-curing resin sheet using the jig or mold to shape it to correspond to the surface shape of the adherend. Here, vacuum forming is preferably TOM forming. TOM stands for "Three Dimension Overlay Method," and applying TOM molding allows for the creation of complex shapes.

[0061] (Second Step) The second step is performed after the first step and is a step to cure the resin layer of the moisture-curable resin sheet. In this step, it is preferable to cure the resin layer to a degree that it can be used as a coating. The curing of the resin layer is not particularly limited as long as it is cured by moisture, but it is usually preferable to leave it in the atmosphere or in a humid environment (for example, in an environment of 50% RH or higher) at room temperature or near thereto (for example, 0°C to 45°C, preferably 5°C to 30°C). The time for leaving it in the atmosphere or in a humid environment is not particularly limited, but for example, it is about 1 hour to 2 weeks, but it is preferable to leave it for about 1 day to 1 week. The moisture-curable resin sheet of the present invention can be cured simply by leaving it in the atmosphere, so the resin layer can be cured industrially without introducing large-scale equipment. Furthermore, even when the adherend is large and difficult to heat, or when the heat resistance of the adherend is low, the resin layer can be properly cured.

[0062] (Third Step) The third step is performed after the second step and involves peeling the transfer layer from the cured resin layer. The transfer layer may be peeled off using a peeling device or by hand. It is preferable to leave the material in the atmosphere for a certain period of time or longer (for example, 1 hour or more, preferably 1 day or more) before peeling off the transfer layer. Once the curing of the resin layer has progressed to a certain extent, it is possible to prevent the uncured or partially cured resin layer from being exposed to the outside, thereby preventing dust and scratches from adhering to the uncured resin layer. Furthermore, by peeling the transfer layer from a resin layer that has cured to a certain extent, it is possible to prevent scratches from being caused to the resin layer during peeling.

[0063] Moisture-curing resin sheets are preferably bonded to various substrates to form a coating. The substrates to which the moisture-curing resin sheets are bonded are not particularly limited, but include vehicle parts such as automotive interior materials and interior materials for non-automotive transport equipment; vehicle exterior materials such as automotive exterior materials and exterior materials for non-automotive transport equipment; exterior materials for electrical appliances, general merchandise, heavy machinery, ships, aircraft, etc.; exterior walls or roofing materials for houses and buildings; bridges, steel frames, plants, wind turbine blades, etc. Among these, use on vehicles and vehicle parts is preferred, and among these, use on automotive exterior materials and exterior materials for non-automotive transport equipment is particularly preferred. Vehicle exterior materials are preferably the exterior of the vehicle body, but may also be hoods, roofs, door panels, bumpers, fuel filler panels, trunk lids, rear gates, etc. When the moisture-curing resin sheet is bonded to vehicle exterior materials, it may be bonded to exterior materials already attached to the vehicle body, or to exterior materials before they are attached to the vehicle body. Furthermore, the material of the adherend is not particularly limited, but may be any of resin materials, inorganic materials such as ceramics, or metallic materials such as steel, although metallic materials such as steel are preferred among these. In addition, a base layer or the like may be appropriately formed on the surface of the adherend to which the moisture-curing resin sheet is attached.

[0064] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. The measurement method and evaluation method in these examples are as follows.

[0065] (Measurement of peel strength (max. Fbf @ 50% RH)) (1) A moisture-curing resin sheet stored in an aluminum pouch (product name "Lamizip Stand Type Aluminum" (manufactured by Seisan Nippon Co., Ltd.)) was removed from its frozen state (-20°C). After the moisture-curing resin sheet reached room temperature, the aluminum pouch was opened and the moisture-curing resin sheet was removed from the aluminum pouch and exposed to an environment of room temperature and 50% RH. (2) The moisture-curing resin sheet was cut to a width of 25 mm and the resin layer side of the moisture-curing resin sheet was attached to a painted board, which was an SPCC-SD urethane coating test piece, using a squeegee. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, the transfer layer was peeled off from the moisture-curing resin sheet attached to the painted board, and a 180° peel test was performed to measure the peel strength. The peel strength was measured within 3 hours of exposure to the moisture-curing resin sheet in an environment of room temperature and 50% RH, and within 1 hour of attaching the moisture-curing resin sheet to the painted board. (4) The maximum value of the peel strength at a sweep distance of 25 mm to 75 mm was defined as the peel force (max. Fbf @ 50% RH).

[0066] (Measurement of peel strength (max. Fbf @ 10% RH)) The environment was changed from room temperature and 50% humidity to room temperature and 10% humidity. The peel strength (max. Fbf @ 10% RH) was measured one hour after exposure of the moisture-curable resin sheet to the room temperature and 10% humidity environment. Otherwise, the peel strength (max. Fbf @ 10% RH) was measured using the same method as for the measurement of peel strength (max. Fbf @ 50% RH).

[0067] (Adhesion) With the transfer layer attached, the resin layer side of the moisture-curing resin sheet was attached to a coated board, which was an SPCC-SD urethane coating test piece, using a squeegee, and the adhesion of the moisture-curing resin sheet was evaluated according to the following criteria: A: No lifting or peeling occurred between the transfer layer and the resin layer. B: Some lifting occurred between the transfer layer and the resin layer, but this did not pose a practical problem. C: Significant lifting or peeling occurred between the transfer layer and the resin layer.

[0068] (Measurement of peel strength (ave. Faf)) (1) A moisture-curing resin sheet stored in an aluminum pouch (product name "Lamizip Stand Type Aluminum" (manufactured by Seisan Nippon Co., Ltd.)) was removed from its frozen state (-20°C). After the moisture-curing resin sheet reached room temperature, the aluminum pouch was opened and the moisture-curing resin sheet was removed from the aluminum pouch. The moisture-curing resin sheet, now at room temperature and 50% RH humidity, was exposed to the environment for one month. (2) The moisture-curing resin sheet was cut to a width of 25 mm, and the resin layer side of the moisture-curing resin sheet was attached to a painted board (Standard Test Piece Co., Ltd., SPCC-SD urethane painted test piece) using double-sided tape. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, the transfer layer was peeled off from the moisture-curing resin sheet attached to the painted board, and a 180° peel test was performed to measure the peel strength. (4) The average value of the peeling strength at sweep distances of 25 mm to 75 mm was defined as the peeling force (ave. Faf).

[0069] (Removability) The removableness of the transfer layer in the moisture-curing resin sheet was evaluated according to the following criteria: A: It could be easily removed without any trigger. B: It could be easily removed once a trigger was created. C: It was difficult to remove the transfer layer. D: It was not possible to remove the transfer layer.

[0070] The components used in the resin layer were as follows: (1) (meth)acrylic resin (A) having isocyanate groups (meth)acrylic resin 1: Acrylic resin having multiple isocyanate groups in the side chain, weight-average molecular weight 67000, glass transition temperature (Tg) 55°C, NCO equivalent 1030, solid content concentration (NV) 45.0 mass% (meth)acrylic resin 2: Acrylic resin having multiple isocyanate groups in the side chain, weight-average molecular weight 67000, glass transition temperature (Tg) 45°C, NCO equivalent 1030 (meth)acrylic resin 3: Acrylic resin having multiple isocyanate groups in the side chain, weight-average molecular weight 67000, glass transition temperature (Tg) 75°C, NCO equivalent 1030, solid content concentration (NV) 40.1 mass% (Meth)acrylic resin 4: Acrylic resin having multiple isocyanate groups in its side chains, weight-average molecular weight 150,000, glass transition temperature (Tg) 55°C, NCO equivalent 1030, solids content (NV) 40.3% by mass. (Meth)acrylic resin 5: Acrylic resin having multiple isocyanate groups in its side chains, weight-average molecular weight 67,000, glass transition temperature (Tg) 55°C, NCO equivalent 1030, solids content (NV) 39.1% by mass. (Meth)acrylic resin 6: Acrylic resin having multiple isocyanate groups in its side chains, weight-average molecular weight 88,000, glass transition temperature (Tg) 50°C, NCO equivalent 1200, solids content (NV) 45.3% by mass. (Meth)acrylic resin 7: Acrylic resin having multiple isocyanate groups in its side chain, weight-average molecular weight 72,000, glass transition temperature (Tg) 60°C, NCO equivalent 1030, solids content (NV) 47.2% by mass.

[0071] (2) Compounds (B) having multiple isocyanate groups other than (meth)acrylic resin (A) Isocyanate 1: Trade name "Takenate D-178NL", manufactured by Mitsui Chemicals, Inc., HDI allophanate, isocyanate group content 19% by mass, solid content (NV) 100% by mass Isocyanate 2: Trade name "Desmodule N100", manufactured by Covestro, HDI biuret, isocyanate group content 22% by mass, solid content (NV) 100% by mass Isocyanate 3: Trade name "Takenate D-170NH", manufactured by Mitsui Chemicals, Inc., HDI nurate, isocyanate group content 22.4% by mass, solid content (NV) 100% by mass Isocyanate 4: Product name "Desmodule UN3790BAN / CAO", manufactured by Covestro, HDI nurate, isocyanate group content 16.3% by mass, solids content (NV) 90.4% by mass Isocyanate 5: Product name "Takenate D-160N", manufactured by Mitsui Chemicals, Inc., HDI adduct, isocyanate group content 9.5% by mass, solids content (NV) 75.0% by mass Isocyanate 6: Product name "Takenate M-631N", manufactured by Mitsui Chemicals, Inc., urethane prepolymer, isocyanate group content 4.5% by mass, solids content (NV) 50% by mass

[0072] Catalyst: Product name "U-CAT660M", manufactured by Sunapro Co., Ltd., amine compound, solids content (NV) 100% by mass. Pigment: Product name "NSP-RF 001A WHITE", manufactured by Nikko Bigs Co., Ltd., white pigment, solids content (NV) 70.0% by mass. Surface modifier: Product name "BYK-326", manufactured by BYK, solids content (NV) 99% by mass.

[0073] The resin films used as the transfer layer and protective layer in the examples and comparative examples are as follows: (Transfer layer) Resin film 1: Product name "Convenience Store Film PP Type Transparent", manufactured by Okamoto Co., Ltd., thickness 100 μm Resin film 2: Surface of resin film 1 was peeled off with a fluorine-based release agent (6N / 25 mm; peeling force using Nitto Denko Corporation's No. 31B tape) Resin film 3: Surface of resin film 1 was peeled off with a long-chain alkyl-based release agent (6N / 25 mm; peeling force using Nitto Denko Corporation's No. 31B tape) Resin film 4: Product name "Convenience Store Film PP Type Transparent", manufactured by Okamoto Co., Ltd., thickness 300 μm Resin film 5: Long-chain alkyl-based release agent (0.4 Resin film 6: Surface of resin film 1 is peeled off with a fluorine-based release agent (4N / 25mm; peeling force using Nitto Denko Corporation's No. 31B tape). Resin film 7: Surface of unoriented polyethylene terephthalate film resin film (Nakamoto Pax Co., Ltd., A-PET, 100 μm thick) is peeled off with a Si-based release agent (0.2N / 25mm; peeling force using Nitto Denko Corporation's No. 31B tape). Resin film 8: Surface of resin film 1 is peeled off with a long-chain alkyl-based release agent (3N / 25mm; peeling force using Nitto Denko Corporation's No. 31B tape). Resin film 9: Surface of resin film 1 is peeled off with a long-chain alkyl-based release agent (0.2N / 25mm; peeling force using Nitto Denko Corporation's No. 31B tape). (Protective layer) Resin film A: Surface of PET film (manufactured by Nakamoto Pax Co., Ltd., product name NS-50MA, thickness 50 μm) has been peeled off with Si-based release agent "MA".

[0074] (Example 1) To a solution of (meth)acrylic resin 1 (78.63 parts by mass of (meth)acrylic resin 1 on a solids basis), 15.17 parts by mass of isocyanate 1 on a solids basis, 0.76 parts by mass of catalyst on a solids basis, 2.89 parts by mass of pigment on a solids basis, and 0.51 parts by mass of surface modifier on a solids basis were added to prepare a moisture-curable resin composition solution. The obtained moisture-curable resin composition solution was applied to a resin film A as a protective layer using an applicator so that the thickness of the coating film after drying was 60 μm. Then, the solvent was dried by heating in an oven at 80°C for 5 minutes to form a resin layer. A resin film 1 as a transfer layer was laminated onto the obtained resin layer to produce a moisture-curable resin sheet, and the prepared moisture-curable resin sheet was placed in an aluminum pouch (product name "Lamizip Stand Type Aluminum" (manufactured by Seisan Nippon Co., Ltd.)) and stored in a frozen state (-20°C).

[0075] (Examples 2-14, Comparative Examples 1-9) The process was carried out in the same manner as in Example 1, except that moisture-curable resin compositions were prepared by blending each component as shown in Tables 1-4, and moisture-curable resin sheets were produced using the transfer layer and protective layer shown in Tables 1-4. Note that the blending amounts of each component in the resin layers shown in Tables 1-4 are based on solid content.

[0076]

[0077]

[0078]

[0079] In the moisture-curing resin sheets of Examples 1 to 14, the peel force (max. Fbf) is 2 N / 25 mm or more, so when the moisture-curing resin sheet is attached to the substrate, the occurrence of lifting between the transfer layer and the resin layer can be suppressed, resulting in good adhesion of the moisture-curing resin sheets of Examples 1 to 14. Also, in the moisture-curing resin sheets of Examples 1 to 14, the peel force (ave. Faf) is 0.5 N / 25 mm or less, so after the resin layer has cured, it is easy to peel the transfer layer from the moisture-curing resin sheet, resulting in good peelability. On the other hand, in the moisture-curing resin sheet of Comparative Example 5, the peel force (max. Fbf) is less than 2 N / 25 mm, so when the moisture-curing resin sheet is attached to the substrate, lifting occurs between the transfer layer and the resin layer, resulting in poor adhesion of the moisture-curing resin sheets of Examples 1 to 13. Furthermore, in the moisture-curable resin sheets of Comparative Examples 1-4 and 6-9, the peel force (ave. Faf) is greater than 0.5 N / 25 mm, so after curing the resin layer, the transfer layer cannot be easily peeled off the moisture-curable resin sheet, resulting in poor peelability.

[0080] 10 Moisture-curing resin sheet 11 Resin layer 12 Transfer layer 13 Protective layer

Claims

1. A moisture-curable resin sheet comprising a transfer layer and a resin layer made of a moisture-curable resin composition, wherein the peel force (max. Fbf) when peeling the transfer layer from the resin layer before curing, as measured by the following measurement method, is 2 N / 25 mm or more, and the peel force (ave. Faf) when peeling the transfer layer from the resin layer after curing, as measured by the following measurement method, is 0.5 N / 25 mm or less. [Peel force (max. Fbf) when peeling the transfer layer from the resin layer before curing] (1) Expose the moisture-curable resin sheet at room temperature to an environment with room temperature and humidity of 5% RH or more and 50% RH or less. (2) Cut the moisture-curable resin sheet to a width of 25 mm, and attach the resin layer side of the moisture-curable resin sheet to a coated plate which is an SPCC-SD urethane coating test piece using a squeegee. (3) Within 3 hours of exposure to a moisture-curing resin sheet in an environment of room temperature and humidity between 5% RH and 50% RH, and within 1 hour of attaching the moisture-curing resin sheet to the painted board, the transfer layer is peeled off the moisture-curing resin sheet attached to the painted board at a measurement temperature of 25°C and a tensile speed of 300 mm / min, and a 180° peel test is performed to measure the peel strength. (4) The maximum value of the peel strength at a sweep distance of 25 mm to 75 mm is defined as the peel force (max. Fbf). [Peel force (ave. Faf) when peeling the transfer layer from the cured resin layer] (1) The moisture-curing resin sheet is exposed to an environment of room temperature and humidity of 50% RH for one month. (2) The moisture-curing resin sheet is cut to a width of 25 mm, and the resin layer side of the moisture-curing resin sheet is attached to the painted board, which is an SPCC-SD urethane coating test piece, using double-sided tape. (3) Under the conditions of a measurement temperature of 25°C and a tensile speed of 300 mm / min, the transfer layer is peeled off from the moisture-curing resin sheet attached to the painted board, and a 180° peel test is performed to measure the peel strength. (4) The average value of the peel strength over a sweep distance of 25 mm to 75 mm is defined as the peel force (ave. Faf).

2. The moisture-curable resin sheet according to claim 1, wherein the peeling force (max. Fbf) when peeling the transfer layer from the resin layer before curing is 5 N / 25 mm or more.

3. The moisture-curable resin sheet according to claim 1, wherein the peeling force (ave. Faf) when peeling the transfer layer from the cured resin layer is 0.25 N / 25 mm or less.

4. The moisture-curable resin sheet according to claim 1, wherein the moisture-curable resin composition comprises a (meth)acrylic resin (A) having an isocyanate group.

5. The moisture-curable resin sheet according to claim 4, wherein the weight-average molecular weight of the (meth)acrylic resin (A) is 10,000 or more and 200,000 or less.

6. The moisture-curable resin sheet according to claim 4, further comprising a compound (B) having a plurality of isocyanate groups other than the (meth)acrylic resin (A).

7. The moisture-curable resin sheet according to claim 6, wherein the compound (B) has a molecular weight of 2000 or less.

8. The moisture-curable resin sheet according to claim 4, wherein the content of the (meth)acrylic resin (A) in the moisture-curable resin composition is 30% by mass or more.

9. The moisture-curable resin sheet according to claim 8, wherein the content of the (meth)acrylic resin (A) in the moisture-curable resin composition is 65% by mass or more and 92% by mass or less.

10. The moisture-curable resin sheet according to claim 4, wherein the (meth)acrylic resin (A) has isocyanate groups in its side chains.

11. A vehicle part having a coating formed from a moisture-curing resin sheet according to claim 1 or 2.

12. A vehicle having a coating formed from a moisture-curing resin sheet as described in claim 1 or 2.

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