Transfer sheet, decorative molded article, and method for producing decorative molded article

Abstract

Provided is a transfer sheet capable of imparting, to the surface of a decorative molded article, a concave-convex shape that is easily visible from all angles. The transfer sheet has a transfer layer on a release sheet, the release sheet has a release layer and a base material in this order from the transfer layer side, and the release layer has a concavo-convex portion containing a binder resin and a matting agent and having a plurality of convex portions on the transfer layer side. And a flat portion which is relatively flat on the surface on the transfer layer side than the uneven portion. The plurality of protrusions of the uneven portion of the release layer are in contact with the transfer layer.

Description

Technical Field

[0001] This invention relates to transfer printing sheets, decorative molded articles, and methods for manufacturing decorative molded articles. Background Art

[0002] For resin molded products used in automotive interior and exterior trim, building materials, interior finishes, and home appliances, as well as for resin molded products made of organic glass, a substitute for inorganic glass, lamination technology using decorative sheets is employed to enhance surface protection and design. The decorative sheets used in this technology can be broadly categorized into laminated decorative sheets and transfer-type decorative sheets (i.e., transfer sheets).

[0003] Laminated decorative sheets are laminated onto a supporting substrate with a protective layer positioned on the outermost surface, and then a resin is laminated onto the supporting substrate, allowing the supporting substrate to be integrated into the resin molded article. Transfer-type decorative sheets, on the other hand, are laminated onto a supporting substrate with a protective layer, either directly or through a flat portion provided as needed, and then a resin is laminated on the opposite side of the supporting substrate. The supporting substrate is then peeled off, preventing any residue from remaining on the resin molded article. These two types of decorative sheets are used differently depending on the shape of the resin molded article, the desired function, and other factors.

[0004] In the case of transfer-type decorative sheets, the design of the resin composition for forming the protective layer is more difficult than with laminated types because other layers such as a design layer or a bonding layer are sometimes laminated on the protective layer, and when there is a flat portion, the protective layer is laminated on the flat portion. During the molding process, the transfer substrate must be peeled off from the protective layer, and the surface exposed by peeling off the transfer substrate must exhibit excellent physical properties.

[0005] Furthermore, the injection molding simultaneous decoration method is used to decorate resin molded articles with complex surface shapes, such as three-dimensional curves. This method involves integrating a decorative sheet inserted into an in-mold mold with the molten injection resin injected into the mold cavity during injection molding, thereby decorating the surface of the resin molded article. Depending on the composition of the decorative sheet integrated with the resin molded article (the aforementioned laminated and transfer-type decorative sheets), the method is generally categorized into injection molding simultaneous lamination and injection molding simultaneous transfer methods.

[0006] In the simultaneous transfer decoration method for injection molding, a transfer sheet is placed with its transfer layer facing the inside of the mold. A heating plate is used to heat the transfer layer, shaping the sheet to the mold's internal shape. Next, molten injection resin is injected into the mold cavity, integrating the transfer sheet and the injected resin. The resin molded article is then cooled and removed from the mold. The transfer substrate of the transfer sheet is then peeled off, resulting in a decorated molded article with a decorative layer to which the transfer layer has been transferred.

[0007] Prior art literature Patent Literature Patent Document 1: Japanese Patent No. 4885281 Patent Document 2: Japanese Patent No. 6866963 Summary of the Invention

[0008] Problems to be solved by the invention Products requiring a matte finish are decorated using transfer sheets with a matte layer having fine irregularities. Patent Documents 1 and 2 disclose methods for producing molded products with varying matte finishes on their surfaces using transfer sheets with a matte layer partially applied to a substrate.

[0009] In these transfer sheets, a matte layer is disposed between the flat portion and the substrate. Furthermore, on the side of the flat portion opposite to the matte layer side, a transfer layer including a protective layer is provided. When the transfer sheet is applied to injection molding, the flat portion is significantly compressed due to the heat and pressure during molding. The matte layer, being harder than the flat portion, deforms less. As a result, when the transfer sheet is applied to injection molding, the uneven shape of the matte layer is transferred to the transfer layer, giving the surface of the resulting decorative molded article a textured design.

[0010] However, when using conventional transfer sheets, the concave and convex shapes on the surface of the decorative molded article are sometimes easily visually recognized when viewed from a direction perpendicular to the surface of the decorative molded article, but are difficult to visually recognize when viewed from a direction nearly horizontal to the surface of the decorative molded article.

[0011] Under such circumstances, the main object of the present invention is to provide a transfer sheet capable of imparting a concave-convex shape that is easily visually recognized from all angles to the surface of a decorative molded article. Furthermore, the present invention also aims to provide a method for manufacturing the transfer sheet and a method for manufacturing a decorative molded article using the transfer sheet.

[0012] Technical solutions to problems The present invention provides an invention in the manner shown below.

[0013] Item 1: A transfer sheet having a transfer layer on a release sheet, wherein the release sheet has a release layer and a substrate sequentially from the transfer layer side, the release layer having an uneven portion containing an adhesive resin and a matting agent and having a plurality of protrusions on the transfer layer side, and a flat portion having a surface relatively flat on the transfer layer side compared to the uneven portion, the plurality of protrusions of the uneven portion of the release layer contacting the transfer layer.

[0014] Item 2: The transfer sheet as described in Item 1, wherein the surface of the transfer layer that contacts the uneven portion has an uneven shape by contacting the uneven portion, and the tops of the plurality of protrusions included in the uneven shape of the transfer layer are located closer to the substrate side than the surface of the transfer layer that contacts the flat portion.

[0015] Item 3: The transfer sheet according to Item 1 or 2, wherein the oil absorption of the matting agent contained in the concave-convex portion is 150 ml / 100 g or more.

[0016] Item 4: The transfer sheet as described in any one of items 1 to 3, wherein the average peak height of the plurality of protrusions in the above-mentioned uneven portion is 3.3 μm or more.

[0017] Item 5: The transfer sheet according to any one of Items 1 to 4, wherein the thickness of the flat portion is 5% or more and 650% or less of the average height of the concave-convex portion.

[0018] Item 6: The transfer sheet as described in any one of items 1 to 5, wherein the flat portion contains the matting agent described above.

[0019] Item 7: A decorative molded article, which is formed by laminating the aforementioned transfer layer of the transfer sheet described in any one of items 1 to 6 onto an attached body.

[0020] Item 8: A method for manufacturing a decorative molded article, comprising the steps of bonding the transfer layer of the transfer sheet as described in any one of items 1 to 6 to an attachment body, and stacking the transfer sheet on the attachment body; and the steps of peeling off the release sheet of the transfer sheet and transferring the transfer layer onto the attachment body.

[0021] Effects of the Invention According to the present invention, a transfer sheet can be provided that imparts a raised or recessed shape to the surface of a decorative molded article, which is easily visually recognizable from all angles. Furthermore, the present invention also provides a method for manufacturing the transfer sheet and a method for manufacturing a decorative molded article using the transfer sheet. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the cross-sectional structure of one type of transfer sheet of the present invention.

[0023] Figure 2 This is a schematic diagram of the cross-sectional structure of one type of transfer sheet of the present invention.

[0024] Figure 3 This is a schematic diagram of a cross-sectional structure of a decorative molded article of a transfer substrate with the present invention.

[0025] Figure 4 This is a schematic diagram of a cross-sectional structure of a decorative molded article of a transfer substrate with the present invention.

[0026] Figure 5 This is a schematic diagram of the cross-sectional structure of one embodiment of the decorative molded article of the present invention. Detailed Implementation

[0027] The transfer sheet of the present invention is a transfer sheet having a transfer layer on a release sheet. The release sheet is characterized by comprising a release layer and a substrate in this order from the transfer layer side. The release layer has a concave-convex portion containing an adhesive resin and a matting agent and having multiple convex portions on the transfer layer side, and a flat portion whose surface on the transfer layer side is relatively flat compared to the concave-convex portion. The multiple convex portions of the concave-convex portion of the release layer are in contact with the transfer layer. The transfer sheet of the present invention, having this feature, can impart a concave-convex shape to the surface of a decorative molded article that is easily visually recognized from all angles. The transfer sheet of the present invention, the decorative molded article with a transfer substrate, and the decorative molded article are described in detail below.

[0028] In the present invention, the numerical range indicated by “~” means “above” or “below”. For example, the expression 2 to 15 mm means “above 2 mm and below 15 mm”. In the numerical ranges recorded progressively in this specification, the upper limit value or lower limit value recorded in a certain numerical range can be replaced by the upper limit value or lower limit value of other numerical ranges recorded progressively. In addition, the upper limit value and the upper limit value, the upper limit value and the lower limit value, or the lower limit value and the lower limit value recorded separately can also be combined to serve as numerical ranges. In addition, in the numerical ranges recorded in this specification, the upper limit value or the lower limit value recorded in a certain numerical range can also be replaced by the value shown in the examples.

[0029] [Transfer sheet 10] like Figure 1 and Figure 2 As shown in the schematic diagram of , the transfer sheet 10 of the present invention has a transfer layer 30 on a release sheet 20. The release sheet 20 has a peeling layer 23 and a base material 22 in order from the transfer layer 30 side. The peeling layer 23 has a concave-convex portion 24 and a flat portion 25. The concave-convex portion 24 has a plurality of convex portions on the transfer layer 30 side. In addition, the surface of the flat portion 25 on the transfer layer 30 side is relatively flat compared to the concave-convex portion 24. When the transfer sheet 10 of the present invention is viewed from the release sheet 20 side, it is preferred that the concave-convex portions 24 and the flat portion 25 are alternately formed, and it is preferred that the concave-convex portions 24 and the flat portion 25 are alternately formed to form a pattern. The shape of the pattern formed by the concave-convex portions 24 and the flat portion 25 will be described later (for example, a wood grain duct pattern, etc.).

[0030] In the transfer sheet 10 of the present invention, a plurality of protrusions of the uneven portion 24 of the release layer 23 contact the transfer layer 30. Figure 1 and Figure 2In the schematic diagram, multiple protrusions of the uneven portion 24 of the release layer 23 contact the protective layer 32 of the transfer layer 30. The surface of the release sheet 20 side of the transfer layer 30 contacts the uneven portion 24 and the flat portion 25 of the release layer 23. The gaps (recesses) in the uneven shape of the uneven portion 24 are formed by the outermost layer (in the mold release sheet 20 side) of the transfer layer 30. Figure 1 and Figure 2 The middle layer is filled with protective layer 32).

[0031] exist Figure 1 In this process, the recesses of the uneven portion 24 do not contain the resin composition forming the flat portion 25. That is, when forming the uneven portion 24 and the flat portion 25, the resin composition forming the flat portion 25 is applied to a location different from the location where the uneven portion 24 is formed. However... Figure 2 In this process, a portion of the recess of the uneven portion 24 contains the resin composition that forms the flat portion 25. That is, when the flat portion 25 is formed, the resin composition that forms the flat portion 25 is applied from the uneven portion 24 and partially impregnated in the recess of the uneven portion 24.

[0032] exist Figure 1 and Figure 2 In this process, the surface of the transfer layer 30 that contacts the raised portion 24 has a raised-low shape due to contact with the raised portion 24. Furthermore, the tips of the multiple protrusions included in the raised-low shape of the transfer layer 30 are located further towards the substrate 22 than the surface of the transfer layer 30 that contacts the flat portion 25. Therefore, after the release sheet 20 is peeled off from the transfer layer 30, the protrusions of the raised-low shape on the surface of the transfer layer 30 protrude more than the portion containing the flat portion (see reference). Figure 5 This makes it easier to visually identify the concave and convex shapes when viewed from various angles, and is therefore a preferred choice.

[0033] exist Figure 1 and Figure 2 In the transfer layer 30, from the side of the release sheet 20, there are a protective layer 32, a base layer 34, a printing layer 36, and a bonding layer 38 in sequence. In the transfer sheet 10 of the present invention, the transfer layer 30 preferably has a protective layer 32, while the base layer 34, the printing layer 36, and the bonding layer 38 are layers provided as needed.

[0034] <Substrate 22> In this invention, the substrate serves as a transfer substrate for transferring the transfer layer onto the substrate. This is achieved by using the transfer sheet of this invention (for example, referencing...). Figure 1 、 Figure 2 By transferring the transfer onto the substrate, a decorative molded product with an attached transfer substrate can be obtained (e.g., see reference). Figure 3 、 Figure 4 Furthermore, decorative molded articles can be obtained by peeling a release sheet containing the substrate and a release layer from a decorative molded article with an attached transfer substrate.

[0035] The substrate can be in the form of a sheet or a film. Examples of substrates include plastic films made from resins such as polyethylene, polypropylene, and other polyolefin resins; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer, and other ethylene resins; polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, and other polyester resins; poly(methyl methacrylate), poly(ethyl methacrylate), and other acrylic resins; styrene resins such as polystyrene; and polyamide resins represented by nylon 6 or nylon 66. Among these plastic films, biaxially stretched polyester films with excellent heat resistance and dimensional stability are preferred.

[0036] The thickness of the substrate is preferably 12 to 150 μm, more preferably 25 to 100 μm. In addition, in order to improve the adhesion with the release layer, the substrate surface may be pretreated with physical treatments such as corona discharge treatment or oxidation treatment, or coated with a coating known as an anchoring agent or primer.

[0037] Furthermore, an antistatic layer can be provided on the side of the substrate opposite to the release layer side. By providing an antistatic layer, static electricity on the transfer sheet can be suppressed, thereby preventing foreign matter adhesion. Therefore, the transfer operability can be improved. The antistatic layer can be in contact with the substrate, or an anti-adhesion layer, primer, etc., can be provided between the antistatic layer and the substrate.

[0038] <Peeling Layer 23> The release layer has an uneven portion and a flat portion. The uneven portion has multiple protrusions on the transfer layer side. The substrate-side surface of the uneven portion is flat. Furthermore, the transfer layer-side surface of the flat portion is relatively flat compared to the uneven portion. Additionally, the substrate-side surface of the flat portion is flat. The uneven portion and the flat portion of the release layer will be described separately below.

[0039] (Concave and convex parts 24) The raised and recessed portions are only provided on a portion of one side surface of the substrate. By partially forming the raised and recessed portions, the surface of the transfer layer (the interface between the transfer layer and the release layer) can be given a raised and recessed shape corresponding to the raised and recessed shape of the portions. By using the transfer sheet of the present invention, for example, it is possible to manufacture decorative molded articles with designs that give rise to patterns with a gloss difference within the protective layer.

[0040] The uneven portion 24 of the release layer 23 may contact the surface of the substrate, or other layers such as a primer coating or an easy-bonding layer (e.g., layers that increase the adhesion between the substrate and the release layer 23) may be provided between the substrate and the uneven portion 24, and the uneven portion 24 may contact the surface of these other layers. Similarly, the flat portion 25 of the release layer 23 (described later) may contact the surface of the substrate, or other layers such as a primer coating or an easy-bonding layer (e.g., layers that increase the adhesion between the substrate and the release layer 23) may be provided between the substrate and the flat portion 25, and the flat portion 25 may contact the surface of these other layers. The uneven portion 24 of the release layer 23 preferably contacts the surface of the substrate. Furthermore, the flat portion 25 of the release layer 23 preferably contacts the surface of the substrate.

[0041] Furthermore, the substrate-side surfaces of the uneven portion 24 and the flat portion 25 of the release layer 23 are preferably formed to contact the surface of the same layer. Specifically, the uneven portion 24 and the flat portion 25 are preferably formed to contact the surface of the substrate or the surface of the other layers (the layer between the substrate and the release layer 23), and more preferably to contact the surface of the substrate.

[0042] As described above, in the transfer sheet of the present invention, a plurality of protrusions of the uneven portion of the release layer contact the transfer layer. Figure 1 and Figure 2 In the schematic diagram, multiple protrusions of the uneven portion 24 of the release layer 23 contact the protective layer 32 of the transfer layer 30. The surface of the release sheet 20 side of the transfer layer 30 contacts the uneven portion 24 and the flat portion 25 of the release layer 23. The gaps (recesses) in the uneven shape of the uneven portion 24 are formed by the surface layer of the release sheet 20 side of the transfer layer 30 (in... Figure 1 and Figure 2 The middle is filled with a protective layer 32).

[0043] In this invention, the raised / uneven portion comprises an adhesive resin and a matting agent. The adhesive resin preferably contains a thermoplastic resin. When using a thermosetting resin to form the raised / uneven portion, a flat portion (described later) is typically formed after the raised / uneven portion has cured, resulting in poor adhesion between the raised / uneven portion and the flat portion. Therefore, when the transfer sheet of this invention is transferred to the substrate, peeling easily occurs between the raised / uneven portion and the flat portion, and a peeling layer remains on the decorative molded article. Furthermore, due to curing shrinkage, the shape of the raised / uneven portion deforms, leading to a tendency for the design of the matte portion to deteriorate when the decorative molded article is manufactured. Moreover, if a flat portion is formed on the raised / uneven portion while the thermosetting resin is not fully cured during the formation of the raised / uneven portion, depending on the degree of curing, the raised / uneven portion may swell due to the solvent contained in the coating liquid used to form the flat portion. This raises concerns about a deterioration in the design of the matte portion when the decorative molded article is manufactured. In this invention, by using a thermoplastic resin as the main component of the adhesive resin to form the raised / uneven portion, good adhesion between the flat portion and the raised / uneven portion can be achieved. As a result, when using the transfer sheet of the present invention for transfer printing, it is less likely to produce a difference in peel strength between the flat portion and the transfer layer (protective layer), resulting in good peelability. Furthermore, by using a thermoplastic resin, there is no effect from curing shrinkage or swelling caused by solvents, thus the uneven shape becomes smooth, resulting in a good appearance when the finished decorative molded article is made. In the present invention, the adhesive resin is preferably composed substantially of a thermoplastic resin.

[0044] Furthermore, in this invention, when the main component of the adhesive resin is thermoplastic resin, "main component" means that the proportion of thermoplastic resin in the adhesive resin is 50% or more, preferably 60% or more, more preferably 80% or more, further preferably 90% or more, and even more preferably 95% or more. In addition, "substantially" means that the proportion of thermoplastic resin in the adhesive resin is 95% or more, preferably 98% or more, and more preferably 100%.

[0045] Furthermore, in this invention, the uneven portion is preferably formed with adhesive resin and matting agent as the main components, and more preferably substantially composed of adhesive resin and matting agent. In this case, "main components" means that the proportion of adhesive resin and matting agent in the uneven portion is 50% or more, preferably 60% or more, more preferably 80% or more, further preferably 90% or more, and even more preferably 95% or more, and "substantially" means that the proportion of adhesive resin and matting agent in the uneven portion is 95% or more, preferably 98% or more, and more preferably 100%.

[0046] From the viewpoint of better realizing the effects of the present invention, the average height of the uneven portion is preferably about 0.1 μm or more, more preferably about 0.5 μm or more, and even more preferably about 1.0 μm or more, and preferably about 8 μm or less, more preferably about 6 μm or less, and even more preferably about 4 μm or less. Examples of preferred ranges include 0.1 to 8 μm and 0.5 to 6 μm. The method for measuring this average height is as described in the section on "Structural Analysis of the Peel Layer" below, specifically according to the method described in the examples.

[0047] Furthermore, from the viewpoint of better realizing the effects of the present invention, the average peak height of the uneven portion is preferably about 1.5 μm or more, more preferably about 2.0 μm or more, further preferably about 2.5 μm or more, and preferably about 10 μm or less, more preferably about 8 μm or less, further preferably about 6 μm or less. Examples of preferred ranges include 1.5 to 10 μm and 2 to 8 μm. The average peak height of the uneven portion refers to the average height of the top 10% of the tallest protrusions among the heights of the protrusions included in the uneven portion (based on the position of the transfer layer side surface of the substrate). For example, in the case where the uneven portion includes 50 protrusions, it is the average height of the top 5 tallest protrusions. The method for measuring this average peak height is as described in the section on "Structural Analysis of the Release Layer" below, specifically according to the method described in the examples.

[0048] Furthermore, to maximize the effects of the present invention, the degree of peak height dispersion (%) (coefficient of variation = standard deviation / average value) is preferably between 32% and 80%, more preferably between 35% and 75%, and even more preferably between 40% and 65%. The method for measuring this peak height dispersion (%) is described below in the "Analysis of the Structure of the Release Layer," specifically in accordance with the method described in the Examples.

[0049] <Structural Analysis of the Peeling Layer> Regarding the structural analysis of the uneven portions of the release layer, when a sheet with uneven portions printed on the substrate and no flat portions printed is available, this sheet is used as the analysis object. A commercially available shape analysis laser microscope (e.g., Keyence VK-X1000) is used. Measurements are taken at three locations, with an arbitrary 100μm width of the uneven portion as the measurement area. The substrate surface with the release layer is then set as the zero point for height. Alternatively, when the aforementioned sheet is not available, as another structural analysis method, a commercially available scanning electron microscope (e.g., Hitachi High Technology Co., Ltd. FlexSEM1000II) is used to observe the cross-section of a sample of the transfer sheet after cross-sectional grinding, and the height of the uneven portion in a 50μm wide area is measured six times. It should be noted that the structural analysis method using cross-sectional observation requires more time.

[0050] The area ratio of the uneven portion within the substrate surface is selected based on the pattern shape formed by the uneven portion and the flat portion, and is preferably 1% or more, more preferably 5% or more, further preferably 10% or more, further preferably 12% or more, and further preferably 15% or more. Furthermore, this area ratio is preferably 99% or less, more preferably 95% or less, further preferably 90% or less, further preferably 88% or less, and further preferably 85% or less.

[0051] As thermoplastic resins, examples include polyolefin resins such as polypropylene and polyethylene, polyester resins, polycarbonate resins, acrylonitrile / butadiene / styrene resins (hereinafter also referred to as "ABS resins"), acrylic resins, vinyl chloride resins, and cellulose-based resins. In this invention, the resins listed above can be used alone or in combination. From the viewpoint of the dispersibility of the matting agent and the adhesion to the flat portion, acrylic resins or cellulose-based resins are preferred. Furthermore, since acrylic resins and cellulose-based resins have stability against ionizing radiation, they are suitable for use when ionizing radiation is used to form the protective layer described later. There are no particular limitations on the acrylic resin; examples include homopolymers of (meth)acrylates, copolymers of two or more different (meth)acrylate monomers, or copolymers of (meth)acrylates with other monomers. More specifically, examples of (meth)acrylic resins include poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, methyl methacrylate / butyl methacrylate copolymer, ethyl methacrylate / butyl methacrylate copolymer, ethylene / methyl methacrylate copolymer, styrene / methyl methacrylate copolymer, and other (meth)acrylates. Examples of cellulose resins include nitrocellulose resins.

[0052] The thermoplastic resin preferably has a weight-average molecular weight of 10,000 to 200,000, more preferably 30,000 to 150,000. This molecular weight range facilitates adjustment of the uneven portion-forming coating liquid and improves the shape stability of the uneven portion. The "weight-average molecular weight" herein refers to the polystyrene-equivalent weight-average molecular weight measured by gel permeation chromatography (GPC).

[0053] The average particle size of the matting agent contained in the uneven portions is preferably 0.5 μm or more. By ensuring that the average particle size of the matting agent is 0.5 μm or more, it is easy to form the uneven shape caused by the uneven portions on the protective layer. In order to impart a sufficiently large uneven shape to the protective layer, the average particle size of the matting agent is preferably 1.0 μm or more, more preferably 2.0 μm or more, and even more preferably 3.0 μm or more. Furthermore, considering the visual recognizability of the printed layer of the area with the uneven shape from the uneven portions after the decorative molded article is manufactured, as well as the ease of forming the uneven portions, the average particle size of the matting agent is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less.

[0054] The ratio of the average particle size of the matting agent to the average height of the uneven portion is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.4 or more. By satisfying this ratio, sufficient matting effect can be imparted to the decorative molded article. On the other hand, when the uneven portion is thinner than the average particle size of the matting agent, the matting agent may detach from the uneven portion. Therefore, considering the retention of the matting agent, this ratio is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. In this specification, the average particle size is the arithmetic mean of the particle size obtained by observing a cross-section in the thickness direction of the layer using a scanning electron microscope (SEM) under accelerating voltage of 3.0 kV and magnification of 50,000x, and measuring the non-agglomerated aggregate of 100 randomly selected particles.

[0055] The matting agent can be either inorganic or organic particles. Examples of inorganic particles include silica, alumina, clay, talc, diatomaceous earth, zeolite, calcium carbonate, barium sulfate, zinc oxide, titanium dioxide, and glass beads. Examples of organic particles include various synthetic resin particles, such as melamine resin, benzoguanamine resin, benzoguanamine / melamine / formaldehyde condensate, acrylic resin, polyurethane resin, and styrene resin; one or a mixture of these can also be used. The particle shape can be spherical or amorphous. Silica particles are particularly preferred because they provide a good matte finish on the surface of decorative molded products and have low production costs.

[0056] From the viewpoint of better maximizing the effects of the present invention, the oil absorption capacity of the matting agent is preferably 150 ml / 100g or more, more preferably 200 ml / 100g or more, and even more preferably 250 ml / 100g or more. Regarding the upper limit, examples include 450 ml / 100g or less, and preferred ranges include 150–450 ml / 100g and 200–350 ml / 100g. When the oil absorption capacity of the matting agent contained in the uneven portion is 150 ml / 100g or more, for example, when the resin composition forming the flat portion is formed from above the uneven portion (see reference...). Figure 2 The resin composition is readily absorbed by uneven portions (especially fine recesses), and can appropriately suppress the flattening of the uneven shape of the uneven portions.

[0057] The oil absorption of the matting agent was measured according to the provisions of JIS K 5101-13-2 Part 13: Oil Absorption - Section 2: Boiling Linseed Oil Method.

[0058] The matting agent preferably contains 50 to 180 parts by weight (solid component) of the adhesive resin per 100 parts by weight (solid component). By setting it to 50 parts by weight or more, a suitable micro-uneven shape can be formed on the surface of the uneven portion and on the surface of the flat portion on the uneven portion. As a result, the desired matte design can be given to the decorative molded article. When forming uneven portions containing thermosetting resin and matting agent, due to the low flexibility of the layer, cracks may occur in the uneven portion during the manufacturing process of the decorative molded article, destroying the shape and deteriorating the design of the matte portion after the decorative molded article is manufactured. Based on this situation, it is not possible to increase the amount of matting agent added when using thermosetting resin. The inventors believe that in the present invention, by forming the uneven portion with thermoplastic resin, even if the matting agent is set to the above-mentioned amount, the uneven portion has flexibility, thereby maintaining the shape of the uneven portion during the manufacturing process of the decorative molded article. When considering the formation of uneven shapes, the content of the matting agent is more preferably 75 parts by mass or more, and more preferably 90 parts by mass or more, relative to 100 parts by mass of the adhesive resin (solid component). By setting it to 180 parts by mass or less, the reduction in film strength of the uneven portions can be suppressed, thereby maintaining the uneven shape during the manufacturing process of the transfer sheet and the decorative molded article. Moreover, the peel strength can be made approximately uniform when the release sheet is peeled off, suppressing poor transfer. In addition, the visual recognizability of the printed layer after the decorative molded article is made is improved. The content of the matting agent is more preferably 160 parts by mass or less, and more preferably 140 parts by mass or less.

[0059] From the viewpoint of reducing the adhesion between the uneven portion and the transfer layer surface and improving peelability, the uneven portion preferably contains additives that improve peelability, such as silicone or fluorine. The content of this additive is preferably 0.3 parts by weight or more, more preferably 0.5 parts by weight or more, and more preferably 5 parts by weight or less, more preferably 3 parts by weight or less, relative to 100 parts by weight of the adhesive resin (solid component). Examples of preferred ranges include 0.3 to 5 parts by weight and 0.5 to 3 parts by weight. Furthermore, as described above, when the resin composition forming the flat portion is formed from the uneven portion, since the resin composition forming the flat portion exists in the recess of the uneven portion, it has the advantage of reduced adhesion between the uneven portion and the transfer layer and improved peelability. Therefore, in this case, the advantage of the uneven portion containing additives that improve peelability is reduced.

[0060] The pattern forming the raised and recessed portions is preferably selected appropriately based on the pattern of the printed layer described later. Examples of patterns include wood grain (wood grain conduits), stone grain, fabric grain, sand grain, circles, quadrilaterals, polygons, geometric patterns, and text.

[0061] In forming the raised and recessed areas, additives are first added to a thermoplastic resin and a matting agent as needed to prepare a coating liquid for forming the raised and recessed areas with an appropriate solvent. This coating liquid is then applied to a substrate using known methods such as gravure printing or screen printing, and allowed to dry, thus partially forming the raised and recessed areas.

[0062] (Flat part 25) The flat portion is partially formed on the substrate. That is, there are areas on the substrate with flat portions and areas with uneven portions. Moreover, the recesses of the uneven portions can be impregnated with a resin composition that forms the flat portion. For example, the uneven portion is partially formed on one side surface of the substrate, and then the resin composition that forms the flat portion is applied to the entire surface of the substrate (including the uneven portion), dried, and cured. As a result, a flat portion is formed on the portion of the substrate where the uneven portion is not formed. Then, the resin composition penetrates into the recesses of the uneven portion, and a portion of the recess is filled by the resin composition that forms the flat portion.

[0063] The surface of the transfer layer side of the flat portion is relatively flat compared to the uneven portion. For example, the average peak height of the flat portion is preferably about 4 μm or less, more preferably about 3 μm or less, and even more preferably about 2 μm or less. The method for measuring this average height can be confirmed by the method described in the <Structural Analysis of the Release Layer> section above, specifically by the method described in the examples.

[0064] By arranging flat portions between the patterned concave and convex portions, the pattern of the concave and convex portions can be maintained.

[0065] As described above, in the transfer sheet of the present invention, although the convex portion of the uneven portion contacts the surface of the transfer layer, the flat portion also contacts the surface of the transfer layer.

[0066] The resin component for the flat portion is not particularly limited, as long as it has low adhesion to the surface of the transfer layer (e.g., a protective layer) and is easily peeled off from the substrate. The composition of the resin component forming the flat portion is preferably different from the composition of the resin component forming the uneven portion. Examples of resin components forming the flat portion include cured thermosetting resin compositions and cured ionizing radiation-curable resin compositions. Specific examples include fluorinated resins, silicone resins, acrylic resins, polyester resins, polycarbonate resins, polyolefin resins, polystyrene resins, polyurethane resins, and vinyl chloride / vinyl acetate copolymer resins. Among these resin components, cured ionizing radiation-curable resin compositions with excellent strength and the ability to impart accurate and precise shapes through instantaneous curing are preferred, and cured electron beam-curable resin compositions are more preferred.

[0067] Ionizing radiation-curable resins refer to resins that undergo cross-linking and curing upon irradiation with ionizing radiation, and are resins possessing ionizing radiation-curable functional groups. These ionizing radiation-curable functional groups are groups that undergo cross-linking and curing upon irradiation with ionizing radiation; preferably, functional groups containing olefinic double bonds, such as (meth)acryloyl, vinyl, and allyl groups, are examples. Ionizing radiation refers to rays containing energy quanta capable of polymerizing or cross-linking molecules, found in electromagnetic waves or charged particle beams. Ultraviolet (UV) or electron (EB) beams are commonly used, but also include electromagnetic waves such as X-rays and gamma rays, alpha rays, and charged particle beams such as ion beams. Cured products of electron beam-curable resin compositions are particularly preferred. Specifically, polymerizable monomers and polymerizable oligomers conventionally used as ionizing radiation-curable resins can be appropriately selected as ionizing radiation-curable resins.

[0068] As polymerizable monomers, (meth)acrylate monomers having free radical polymerizable unsaturated groups in their molecules are preferred, among which multifunctional (meth)acrylate monomers are preferred. Examples of multifunctional (meth)acrylate monomers include those having two or more ionizing radiation-curable functional groups in their molecules, and having at least a (meth)acryloyl group in each functional group. From the viewpoint of heat resistance and moldability, the number of functional groups is preferably 2 or more and 8 or less, more preferably 2 or more and 6 or less, further preferably 2 or more and 4 or less, and particularly preferably 2 or more and 3 or less. These multifunctional (meth)acrylate monomers can be used alone or in combination. Furthermore, they can also be used in the form of compositions mixing one or more of these multifunctional (meth)acrylate monomers with one or more polymerizable oligomers described later. By forming a mixture of both, the crosslinking density, inter-crosslinking molecular weight, etc., of the cured product can be adjusted, thereby adjusting various physical properties of the cured product.

[0069] Examples of polymerizable oligomers include (meth)acrylate oligomers having two or more ionizing radiation-curable functional groups in their molecules, with at least one (meth)acryloyl group among these functional groups. Examples include urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyester (meth)acrylate oligomers, polyether (meth)acrylate oligomers, polycarbonate (meth)acrylate oligomers, and acrylic (meth)acrylate oligomers. From the viewpoint of heat resistance and moldability, the number of functional groups in these polymerizable oligomers is preferably 2 or more and 8 or less, more preferably 6 or less, further preferably 4 or less, and particularly preferably 3 or less.

[0070] Especially considering the adhesion to uneven surfaces, acrylic (meth)acrylate compounds and urethane (meth)acrylate compounds are preferred as resin components. Here, "(meth)acrylate" refers to "acrylate or methacrylate". The resin component can be any one of acrylic (meth)acrylate compounds and urethane (meth)acrylate compounds, or a mixture thereof. Acrylic (meth)acrylate compounds and urethane (meth)acrylate compounds can be monomers, oligomers, or a mixture of monomers and oligomers.

[0071] From the viewpoint of heat resistance and moldability, the weight-average molecular weight of the monomers and oligomers used in the flat portion is preferably 250 or more and 30,000 or less, more preferably 250 or more and 20,000 or less, and even more preferably 250 or more and 15,000 or less. The weight-average molecular weight is determined by GPC analysis and converted to the average molecular weight of standard polystyrene.

[0072] In this invention, the flat portion is preferably formed primarily of a cured thermosetting resin composition or a cured ionizing radiation-curable resin composition, and more preferably substantially formed of a cured thermosetting resin composition or a cured ionizing radiation-curable resin composition. In this case, "primary component" means that the proportion of the cured thermosetting resin composition or the cured ionizing radiation-curable resin composition in the flat portion is 50% or more, preferably 60% or more, more preferably 80% or more, further preferably 90% or more, and even more preferably 95% or more. Furthermore, "substantially" means that the proportion of the cured thermosetting resin composition or the cured ionizing radiation-curable resin composition in the flat portion is 95% or more, preferably 98% or more, and more preferably 100%.

[0073] In the resin composition that forms the flat portion, additives such as curing agents and polymerization initiators may also be added as needed.

[0074] Furthermore, to further enhance the effects of the present invention, the concave-convex portion and the flat portion may contain a common binder resin. However, as described above, the composition of the resin component forming the flat portion is preferably different from that of the resin component forming the concave-convex portion. The type of binder resin (thermoplastic resin) is as described in the description of the concave-convex portion.

[0075] To improve release properties from the protective layer, the flat portion may also contain a release agent. Besides silicone, other waxes such as synthetic waxes and natural waxes can be used as release agents. Examples of synthetic waxes include polyolefin waxes such as polyethylene wax and polypropylene wax. Furthermore, from the viewpoints of improving the hardness of the flat portion, suppressing the exudation of the release agent, and improving particle dispersibility, reactive silicone or other cross-linking and curing release agents are preferred. The mass ratio of the release agent to the total solid components of the flat portion is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass.

[0076] From the viewpoint of printability of the protective layer, it is preferable that the difference between the thickness of the flat portion and the average thickness of the adjacent uneven layer is not too large. Specifically, the difference between the thickness of the flat portion and the average thickness of the uneven layer is preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 5 μm or less. The thickness of the flat portion is preferably 5 to 650% of the average height of the uneven portion, more preferably 10 to 450%, and even more preferably 15 to 200%.

[0077] The flat portion may also contain a matting agent. This allows the finished decorative molded article to have a matte finish overall while also creating distinct gloss differences between individual regions. The same matting agent used for the concave and convex portions can be used. From a cost perspective, the inclusion of silica particles is particularly preferred.

[0078] When a matting agent is present in the flat portion, the amount of matting agent added is preferably less than that added in the uneven portion. Specifically, relative to 100 parts by weight of the resin component (solid component) in the flat portion, the amount of matting agent added is preferably 0.1 parts by weight or more and 10 parts by weight or less (solid component), more preferably 1.0 parts by weight or more and 5 parts by weight or less. By setting the amount added within the above range, the desired matte finish can be imparted to the decorative molded article.

[0079] The average particle size of the matting agent contained in the flat portion is preferably 0.5 μm or more, more preferably 0.7 μm or more. By making the average particle size of the matting agent 0.5 μm or more, it is easy to form an uneven shape formed by the flat portion in the protective layer. When considering the visual recognizability of the printed layer after the decorative molded article is manufactured, the average particle size of the matting agent contained in the flat portion is preferably 10 μm or less, more preferably 5 μm or less. In addition, when the gloss difference between the uneven portion and the flat portion is large, the visual recognizability of the uneven portion is better. Therefore, it is preferable that the average particle size of the matting agent contained in the flat portion is 0.2 μm or more smaller than the average particle size contained in the uneven portion, more preferably 0.5 μm or more smaller.

[0080] The ratio of the average particle size of the matting agent to the thickness of the flat portion is preferably 1 or more, more preferably 1.2 or more, and even more preferably 1.4 or more. By satisfying the above values, the decorative molded article can be given a sufficient matte effect. On the other hand, when the flat portion is thinner than the average particle size of the matting agent, the matting agent may detach from the uneven portion. Therefore, considering the retention of the matting agent, this ratio is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. In order to form a design in which there is a gloss difference between the part corresponding to the uneven portion and its surroundings (the part without uneven portion) when the decorative molded article is manufactured, it is preferable that the average particle size, the amount added, and the ratio of the average particle size of the matting agent contained in the uneven portion and the flat portion are different from each other, and it is more preferable that the uneven portion exhibits a more matte finish than the flat portion.

[0081] The flat portion can be formed by a known printing method such as gravure printing, offset printing, letterpress printing, or screen printing.

[0082] [Transfer layer] <Protective layer> The protective layer is provided on the release sheet side of the transfer layer. Regarding the surface shape of the protective layer on the release sheet side, the area formed on the concave-convex portion has a shape corresponding to the concave-convex shape of the concave-convex portion. If the protective layer contacts the flat portion, the area formed on the flat portion has a shape corresponding to the surface shape of the flat portion.

[0083] The protective layer preferably comprises a cured product of a curable resin composition. Examples of the cured product of the curable resin composition include cured products of thermosetting resin compositions, cured products of ionizing radiation-curable resin compositions, and cured products of mixtures thereof. From the perspective of the scratch resistance of the protective layer, a cured product of an ionizing radiation-curable resin composition is preferred. Furthermore, among cured products of ionizing radiation-curable resin compositions, a cured product of an electron beam-curable resin composition is preferred from the perspective of easily completing crosslinking and curing at the time of forming the protective layer.

[0084] A thermosetting resin composition is a composition containing at least a thermosetting resin that is cured by heating. Examples of thermosetting resins include acrylic resins, polyurethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. A curing agent may be added to these curable resins as needed in the thermosetting resin composition.

[0085] Specifically, the ionizing radiation curable resin may be appropriately selected from polymerizable monomers and polymerizable oligomers conventionally used as ionizing radiation curable resins.

[0086] As polymerizable monomers, (meth)acrylate monomers having a free-radically polymerizable unsaturated group in the molecule are preferred, with multifunctional (meth)acrylate monomers being particularly preferred. Examples of multifunctional (meth)acrylate monomers include those having two or more ionizing radiation-curable functional groups in the molecule, with at least one (meth)acryloyl group being one of the functional groups, and preferably those having an acryloyl group. These polymerizable oligomers can be used alone or in combination. The number of functional groups in the polymerizable monomer is preferably 2 or more and 8 or less, more preferably 2 or more and 6 or less, even more preferably 2 or more and 4 or less, and particularly preferably 2 or more and 3 or less.

[0087] Examples of polymerizable oligomers include (meth)acrylate oligomers having two or more ionizing radiation-curable functional groups in the molecule and at least a (meth)acryloyl group as the functional group. Examples include urethane (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyester (meth)acrylate oligomers, polyether (meth)acrylate oligomers, polycarbonate (meth)acrylate oligomers, and acrylic (meth)acrylate oligomers.

[0088] These polymeric oligomers can be used alone or in combination. Polycarbonate (meth)acrylate oligomers are preferred. There are no particular limitations as long as the polycarbonate (meth)acrylate oligomer has carbonate bonds in the main chain and (meth)acrylate groups at the ends or side chains; it can also be a polycarbonate-based urethane (meth)acrylate oligomer having a polycarbonate backbone. From the viewpoint of heat resistance and moldability, the number of functional groups in these polymeric oligomers is preferably 2 or more and 8 or less, more preferably 6 or less, further preferably 4 or less, and particularly preferably 3 or less.

[0089] Regarding ionizing radiation-curable resins, in order to reduce their viscosity, monofunctional (meth)acrylates can be appropriately combined with the aforementioned polyfunctional (meth)acrylates. These monofunctional (meth)acrylates can be used alone or in combination.

[0090] From the viewpoint of heat resistance and formability, the weight average molecular weight of the monomers and oligomers used in the protective layer is preferably 250 or more and 30,000 or less, more preferably 250 or more and 20,000 or less, and even more preferably 250 or more and 15,000 or less.

[0091] The protective layer preferably contains no organic or inorganic particles. The absence of particles in the protective layer makes it easier to visually identify the pattern of the underlying printed layer. "Substantially free of particles" means that the total solid components of the protective layer comprise less than 1% by mass, preferably less than 0.1% by mass, more preferably less than 0.01% by mass, and even more preferably 0% by mass.

[0092] The protective layer may also contain a thermoplastic resin as a resin component other than the cured product of the curable resin composition. By containing a thermoplastic resin in the protective layer, cracking during molding can be suppressed, resulting in good moldability. The thermoplastic resin can be a general-purpose resin such as an acrylic resin, a polyester resin, or a urethane resin. The content of the thermoplastic resin is preferably 0.1 to 20% by mass of the total solid components of the protective layer, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass.

[0093] From the viewpoint of balancing surface hardness and formability, the thickness of the protective layer is preferably 0.5 to 30 μm, more preferably 1 to 20 μm, and even more preferably 1 to 10 μm.

[0094] The protective layer can be formed using well-known printing methods such as gravure printing, offset printing, letterpress printing, and screen printing.

[0095] In addition, although the thermosetting resin composition and / or ionizing radiation curable resin composition can be completely cured at the time of forming the protective layer, from the viewpoint of moldability, the thermosetting resin composition and / or ionizing radiation curable resin composition can also be in an uncured or semi-cured state at the time of forming the protective layer, and after transfer to the adherend, the curing of the thermosetting resin composition and / or ionizing radiation curable resin composition is carried out to make it completely cured.

[0096] <Printed Layer> The printed layer is used to impart the desired design to the decorative molded article. The printed layer can have any pattern, including wood grain, stone grain, cloth grain, sand grain, circular, quadrilateral, polygonal, geometric patterns, text, and full-face printing.

[0097] The printed layer preferably contains a binder resin such as a polyethylene resin, polyester resin, acrylic resin, polyvinyl acetal resin, or cellulose resin, as well as a pigment and / or dye. From a design perspective, the thickness of the printed layer is preferably 0.5 to 40 μm, more preferably 1 to 30 μm.

[0098] The printed layer can be formed by a known printing method such as gravure printing, offset printing, letterpress printing, or screen printing.

[0099] <Joint Layer> The bonding layer improves the adhesion between the substrate (such as a resin molded body) and the transfer layer. Alternatively, if the adhesion between the protective layer and the substrate is good, the bonding layer may not be necessary.

[0100] The bonding layer preferably uses a resin with bonding properties suitable for the material of the adherend. For example, when the material of the adherend is an acrylic resin, it is preferred to use an acrylic resin. In addition, when the material of the adherend is a polyphenylene ether / polystyrene resin, a polycarbonate resin, or a styrene resin, it is preferred to use an acrylic resin, a polystyrene resin, a polyamide resin, etc. that have an affinity with these resins. In addition, when the material of the adherend is a polypropylene resin, it is preferred to use a chlorinated polyolefin resin, a vinyl chloride / vinyl acetate copolymer resin, a cyclized rubber, or a coumarone-indene resin. The bonding layer may also contain additives such as ultraviolet absorbers and infrared absorbers. The thickness of the bonding layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm.

[0101] The bonding layer can be formed using known printing methods such as gravure printing, offset printing, letterpress printing, and screen printing.

[0102] <Undercoat> The primer layer is a layer provided as needed to improve the adhesion between the protective layer and the printed layer.

[0103] The primer layer preferably mainly comprises a resin component. In addition, in order to impart heat resistance when placed in a high temperature environment such as in-mold molding, the resin component of the primer layer preferably comprises a cured product of a curable resin composition. As the curable resin composition, a thermosetting resin composition and an ionizing radiation curable resin composition can be mentioned. The thermosetting resin composition and the ionizing radiation curable resin composition of the primer layer can use the same substances as those exemplified for the thermosetting resin composition and the ionizing radiation curable resin composition as the protective layer. The primer layer particularly preferably comprises a cured product of a thermosetting resin composition. As the thermosetting resin composition, for example, various polyol compounds such as polyether polyols, polyester polyols, acrylic polyols, and curing agents such as isocyanate compounds can be mentioned.

[0104] The thickness of the primer layer is preferably 0.1 to 6 μm, more preferably 0.5 to 5 μm. The primer layer may be a single-layer structure, but may also be a structure in which two or more layers are stacked in consideration of interlayer adhesion and the like.

[0105] The primer layer can be formed by a known printing method such as gravure printing, offset printing, letterpress printing, or screen printing.

[0106] [Decorative molded products] use Figures 1-5 This describes a decorative molded article manufactured using the transfer sheet of the present invention. Figure 3 It comes with Figure 1 The cross-sectional view of the decorative molded article 41 of the transfer substrate shown is shown. Figure 4 It comes with Figure 2 Schematic cross-sectional view of the decorative molded article 41 of the transfer substrate shown. Figure 5 It is from Figure 3 Schematic cross-sectional view of a decorative molded article 41 with a transfer substrate, obtained by peeling off the release sheet 20. The decorative molded article 40 includes an adherend 42 and a transfer layer 30 covering the adherend. Figure 5 In the figure, the transfer layer 30 includes an adhesive layer 38, a printing layer 36, a primer layer 34, and a protective layer 32 in this order from the adherend side. The protective layer 32 is located on the outermost surface of the decorative molded article 40.

[0107] <Attached organism> The adherend is a resin molded body made of resin. The shape of the adherend may be a flat plate or a three-dimensional shape having a curved surface. The adherend may also be colored.

[0108] Resin molded articles can be formed from thermoplastic resins or thermosetting resins. When manufacturing decorative molded articles by in-mold molding, thermoplastic resins are preferred as the resin molded article. Examples of such thermoplastic resins include polystyrene-based resins, polyolefin-based resins, ABS resins (including heat-resistant ABS resins), AS resins, PC / ABS-based resins, PC / AS-based resins, AN resins, polyphenylene ether-based resins, polycarbonate-based resins, polyacetal-based resins, acrylic resins, polyethylene terephthalate-based resins, polybutylene terephthalate-based resins, polysulfone-based resins, and polyphenylene sulfide-based resins.

[0109] Protective layer for decorative molded products The protective layer of the decorative molded article of the present invention has an uneven shape that is substantially complementary to the surface shape of the release layer of the release sheet. Furthermore, the flat portion of the protective layer preferably has an uneven shape that is substantially complementary to the flat portion of the release layer of the release sheet. In the decorative molded article of the present invention, for example, it is preferable that the convex portion of the uneven shape on the surface of the protective layer is more prominent than the flat portion. This surface structure of the decorative molded article results in an uneven shape that is easily visually recognizable from all angles.

[0110] [Method for manufacturing decorative molded products] The method for manufacturing a decorative molded article of the present invention comprises: (1) a step of bonding a transfer layer of a transfer sheet to an adherend to laminate the transfer sheet on the adherend; and (2) a step of peeling off a release sheet of the transfer sheet to transfer the transfer layer to the adherend.

[0111] The transfer sheet of the present invention is particularly suitable for the production of decorative molded products using in-mold molding (injection molding simultaneous transfer decoration). According to the present invention, a pattern with a gloss difference can be transferred onto the surface of a resin molded article with a complex surface shape, such as a three-dimensional curve.

[0112] One embodiment of the method for manufacturing decorative molded articles by in-mold forming includes the following steps: (S1) A process of arranging the transfer layer side of the transfer sheet toward the inside of the mold for in-mold forming; (S2) The process of injecting the body to be attached into the mold for in-mold molding using resin injection; (S3) a step of integrating the transfer sheet with the resin to form a laminated body in which the transfer sheet is laminated on the surface of the resin molded body (adhered body); and (S4) The process of peeling the release sheet of the transfer sheet after removing the laminate from the mold or at the same time as removing the resin molded body from the mold.

[0113] Example The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

[0114] [Examples and Comparative Examples] <Manufacturing of transfer sheets> (Example 1) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 1 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 1 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried. Next, the coating liquid for the flat portions was applied to the areas not coated with the coating liquid 1 for the raised and recessed portions, and the substrate was irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy) to form a release layer with alternating raised and recessed portions and flat portions, thus obtaining the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the raised and recessed portions are shown in Table 1. Next, a protective coating liquid was applied to the release layer of the release sheet, and the sheet was irradiated with an electron beam at 165 keV and 5 Mrad (50 kGy) to form a protective layer with a thickness of 3 μm. Then, a primer coating liquid 1 was applied to the protective layer and dried to form a primer layer with a thickness of 2 μm. Next, a brown ink (acrylic resin composition) was applied to the primer layer by gravure printing and dried to form a wood grain pattern printing layer with a thickness of 6 μm. Next, a bonding layer coating liquid diluted with a solvent was applied to the printing layer and dried to form a heat-sealable bonding layer with a thickness of 2 μm. The transfer sheet of Example 1 (see above) was obtained through the above steps. Figure 1 ).

[0115] (Examples 2-5) The same method as in Example 1 was used except that the thickness of the flat portion was set to the thickness described in Table 1, and transfer sheets of Examples 2 to 5 were obtained (see Figure 1 ).

[0116] (Example 6) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 2 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 2 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried. Next, the coating liquid for the flat portions was applied to the areas not coated with the coating liquid 2 for the raised and recessed portions, and the substrate was irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy) to form a release layer with alternating raised and recessed portions, resulting in the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the flat portions are shown in Table 1. On the release layer of the obtained release sheet, the same procedure as in Example 1 is followed to sequentially form a protective layer, a base layer, a printing layer, and a bonding layer, resulting in the transfer sheet of Example 6 (see Example 6). Figure 1 ).

[0117] (Example 7) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 3 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 3 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried, thereby forming the raised and recessed portions. Next, the coating liquid for the flat portions was applied to the entire surface of the substrate, including the raised and recessed portions, and irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy), thereby forming a release layer with alternating raised and recessed portions and flat portions, resulting in the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the raised and recessed portions are shown in Table 1. On the release layer of the obtained release sheet, the same procedure as in Example 1 is followed to sequentially form a protective layer, a base layer, a printing layer, and a bonding layer, resulting in the transfer sheet of Example 7 (see Example 7). Figure 2 ).

[0118] (Examples 8-9) Except that the thickness of the flat portion is set to the thickness described in Table 1, the same procedure as in Example 7 was followed to obtain the transfer sheets of Examples 8 to 9 (see Table 1). Figure 2 ).

[0119] (Examples 10-11 and Comparative Example 1) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 4 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 4 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried, thereby forming the raised and recessed portions. Next, the coating liquid for the flat portions was applied to the entire surface of the substrate, including the raised and recessed portions, and irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy), thereby forming a release layer with alternating raised and recessed portions and flat portions, resulting in the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the raised and recessed portions are described in Table 1. On the release layer of the obtained release sheet, the same procedure as in Example 7 was followed to sequentially form a protective layer, a base layer, a printing layer, and a bonding layer, respectively, to obtain transfer sheets of Examples 10-11 and Comparative Example 1 (refer to Example 10-11). Figure 2 ).

[0120] (Example 12) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 5 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 5 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried. Next, the coating liquid for the flat portions was applied to the entire surface of the substrate, including the raised and recessed portions, and irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy), thereby forming a release layer with alternating raised and recessed portions and flat portions, resulting in the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the flat portions are shown in Table 1. On the release layer of the obtained release sheet, the same procedure as in Example 7 was followed to sequentially form a protective layer, a base layer, a printing layer, and a bonding layer, respectively, to obtain the transfer sheets of Examples 10-11 (refer to Example 10-11). Figure 2 ).

[0121] (Comparative Example 2) As the substrate for the release sheet, a biaxially stretched polyethylene terephthalate film with a thickness of 75 μm was prepared. Furthermore, a coating liquid 6 for the raised and recessed portions forming the release layer and a coating liquid for the flat portions forming the release layer were prepared. The composition of each coating liquid is described below. Then, the coating liquid 6 for the raised and recessed portions was applied to one side of the substrate surface in a pattern (wood grain conduit pattern) using gravure printing and dried, thereby forming the raised and recessed portions. Next, the coating liquid for the flat portions was applied to the entire surface of the substrate, including the raised and recessed portions, and irradiated with an electron beam at 165 keV and 7 Mrad (70 kGy), thereby forming a release layer with alternating raised and recessed portions and flat portions, resulting in the release sheet. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / mean), and thickness (μm) of the raised and recessed portions are described in Table 1. On the release layer of the obtained release sheet, the same procedure as in Example 7 was followed to sequentially form a protective layer, a base layer, a printing layer, and a bonding layer, respectively, to obtain the transfer sheet of Comparative Example 2 (refer to Example 2). Figure 2 ).

[0122] (Coating liquid for concave and convex parts) Prepare coating solutions 1 to 6 for the uneven portions of the following formulations respectively.

[0123] Coating solution 1 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; matting agent (amorphous silica, average particle size 3μm, oil absorption 250ml / 100g): 130 parts by weight; organosilicon: 2 parts by weight; solvent (ethyl acetate): appropriate amount.

[0124] Coating solution 2 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; matting agent (spherical silica, average particle size 3μm, oil absorption 30ml / 100g): 130 parts by weight; organosilicon: 2 parts by weight; solvent (ethyl acetate): appropriate amount.

[0125] Coating solution 3 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; Matting agent (amorphous silica, average particle size 3μm, oil absorption 250ml / 100g): 130 parts by weight; Solvent (ethyl acetate): appropriate amount.

[0126] Coating solution 4 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; Matting agent (amorphous silica, average particle size 3μm, oil absorption 200ml / 100g): 130 parts by weight; Solvent (ethyl acetate): appropriate amount.

[0127] Coating solution 5 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; Matting agent (amorphous silica, average particle size 3μm, oil absorption 150ml / 100g): 130 parts by weight; Solvent (ethyl acetate): appropriate amount.

[0128] Coating solution 6 for uneven parts: Nitrocellulose resin (thermoplastic resin, weight average molecular weight: 50000): 100 parts by weight; Matting agent (mixture of spherical and amorphous silica, average particle size 3μm, oil absorption 100ml / 100g): 130 parts by weight; Solvent (ethyl acetate): appropriate amount.

[0129] (Apply the coating liquid to the flat areas) Prepare the coating solution for the flat portion of the following formulation.

[0130] Coating solution for flat areas: 84 parts by weight of difunctional polycarbonate acrylate (weight average molecular weight: 5000); 14 parts by weight of pentaerythritol triacrylate (PETA); 5 parts by weight of matting agent (amorphous silica, average particle size 3μm, oil absorption 350ml / 100g); 2 parts by weight of reactive organosilicon; appropriate amount of solvent (mixture of methyl ethyl ketone and isopropanol).

[0131] (Coating liquid for protective layer) Prepare the coating solution for the protective layer with the following formulation.

[0132] Tetrafunctional urethane acrylate (weight average molecular weight: 10000): 95 parts by mass; trifunctional acrylate monomer (weight average molecular weight: 300): 5 parts by mass; solvent (mixture of methyl ethyl ketone and isopropanol): appropriate amount.

[0133] (Coating liquid for primer layer) Prepare a base coat liquid with the following formulation.

[0134] <Coating liquid for primer> 100 parts by weight of acrylic polyol (hydroxyl value: 80 mg KOH / g, Tg: 90°C); 10 parts by weight of XDI (m-xylene diisocyanate); solvent (methyl ethyl ketone): appropriate amount.

[0135] <Structural Analysis of the Release Layer of the Transfer Film> The structure of the release layer of each transfer sheet obtained in the examples and comparative examples was analyzed by the following methods. The average peak height (μm), average height (μm), peak height dispersion (%) (coefficient of variation = standard deviation / average), and thickness (μm) of the flat portion of the release layer are shown in Table 1.

[0136] For cross-sectional structural analysis of the concave and convex portions of the release layer, the analysis was performed on a sheet with the concave and convex portions printed on the substrate, but before the flat portion was printed. A shape analysis laser microscope (Keyence VK-X1000) was used. Measurements were taken at a total of three locations, with an arbitrary 100μm width on the concave and convex portion as the measurement area. The surface of the substrate on which the release layer was formed was set as the height zero point. Alternatively, as another structural analysis method, a scanning electron microscope (FlexSEM1000II, Hitachi High-Technologies Corporation) was used to observe the cross section of a sample of the transfer sheet that had been cross-section-polished. The height of the concave and convex portion in a 50μm-wide area was measured six times, yielding similar measurement results. However, cross-sectional structural analysis using cross-sectional observation requires more time.

[0137] <Manufacturing of Resin Molded Products> Using the transfer sheets obtained in the examples and comparative examples, decorative molded articles were manufactured according to the following procedures. The transfer sheets of Examples 1 to 12 and Comparative Examples 1 to 2 were placed on one side of a set of upper and lower in-mold transfer molds, respectively. At this time, the transfer sheets were placed so that the bonding layer faced the inside of the mold (the side in contact with the injection resin). Next, the mold was tightened, and injection resin (PC / ABS resin) was injected into the mold to obtain a laminate (10 cm × 16 cm × 2 mm thick plate) in which the transfer sheet and the injection resin layer containing the injection resin were integrated. Next, after opening the mold, the release sheet (substrate to flat portion) of the transfer sheet was peeled off from the laminate to obtain the decorative molded articles of Examples 1 to 12 and Comparative Examples 1 to 2.

[0138] Surface Observation and Design Evaluation of Decorative Molded Products The surfaces of the decorative molded articles obtained in the examples and comparative examples were observed using the following methods to confirm whether the raised portions of the surface irregularities were located at a higher position than the flat portions (OK if located at a higher position, NG otherwise), and the visual recognizability (designability) of the surface irregularities was evaluated from various angles. The results are shown in Table 1.

[0139] The decorative molded articles produced in the examples and comparative examples were visually observed at an angle of 60 degrees ± 10 degrees. Visual discernibility was evaluated according to the following criteria based on whether there was a gloss difference between the areas with raised and recessed portions and the flat portions. Evaluations were conducted by 20 subjects, and the average score was calculated.

[0140] (Evaluation criteria for visual recognizability) 2 points: The gloss is obviously poor.

[0141] 1 point: Although there is a lack of gloss, the difference in gloss is less noticeable than the "2 points" rating.

[0142] 0 points: I can't feel any difference in gloss.

[0143] A: The average score of the evaluation benchmark is above 1.8.

[0144] B+: The average score of the evaluation benchmark is above 1.4 and below 1.8.

[0145] B: The average score of the evaluation benchmark is above 1.0 and below 1.4.

[0146] C: The average score of the evaluation benchmark is below 1.0.

[0147] [Table 1] The transfer sheets of Examples 1-12 are transfer sheets with a transfer layer on a release sheet. The release sheet has a release layer and a substrate sequentially arranged from the transfer layer side. The release layer has an uneven portion containing an adhesive resin and a matting agent and having multiple protrusions on the transfer layer side, and a flat portion whose surface is relatively flat compared to the uneven portion on the transfer layer side. The multiple protrusions of the uneven portion of the release layer are in contact with the transfer layer. The transfer sheets of Examples 1-12 can impart an uneven shape to the surface of a decorative molded article that is easily visually recognizable from all angles.

[0148] Explanation of symbols 10: Transfer sheet; 20: Release sheet; 22: Substrate; 23: Release layer; 24: Uneven portion; 25: Flat portion; 30: Transfer layer; 32: Protective layer; 34: Primer layer; 36: Printing layer; 38: Bonding layer; 40: Decorative molded article; 41: Decorative molded article with attached transfer substrate; 42: Attached body.

Claims

1. A transfer sheet, characterized in that: It is a transfer sheet having a transfer layer on a release sheet. The release sheet has a peeling layer and a substrate in this order from the transfer layer side. The peeling layer has: a concavo-convex portion comprising a binder resin and a matting agent and having a plurality of convex portions on the transfer layer side; and A flat portion where the surface on the transfer layer side is relatively flat compared to the concavoconvex portion, The plurality of convex portions of the concavo-convex portion of the release layer are in contact with the transfer layer.

2. The transfer sheet according to claim 1, wherein: The surface of the transfer layer in contact with the concavo-convex portion has a concavo-convex shape by being in contact with the concavo-convex portion. The top ends of the plurality of projections included in the concavo-convex shape of the transfer layer are located closer to the substrate than a surface of the transfer layer in contact with the flat portion.

3. The transfer sheet according to claim 1 or 2, characterized in that: The matting agent contained in the concavo-convex portion has an oil absorption of 150 ml / 100 g or more.

4. The transfer sheet according to claim 1 or 2, wherein: The average peak height of the plurality of convex portions of the concavo-convex portion is 3.3 μm or more.

5. The transfer sheet according to claim 1 or 2, wherein: The thickness of the flat portion is not less than 5% and not more than 650% of the average height of the concave-convex portion.

6. The transfer sheet according to claim 1 or 2, characterized in that: The flat portion contains the matting agent.

7. A decorative molded product, characterized in that: The invention is a decorative molded article in which the transfer layer of the transfer sheet according to claim 1 or 2 is laminated on an adherend.

8. A method for manufacturing a decorative molded product, characterized in that: include: The step of bonding the transfer layer of the transfer sheet according to claim 1 or 2 to an adherend and laminating the transfer sheet on the adherend; and A step of peeling off the release sheet of the transfer sheet to transfer the transfer layer to the adherend.

Images