Decorative sheet and decorative resin molded article

Abstract

To provide a novel decorative sheet having an uneven shape on an outer surface, in which the uneven shape is suitably maintained even by molding and warpage after molding is suppressed.SOLUTION: A decorative sheet including at least a resin layer and a base material layer in order from an outer side, in which an outer surface of the decorative sheet has an uneven shape, the base material layer contains a thermoplastic resin, the resin layer contains polypropylene having a melting peak temperature of 150 °C or higher and a filler, and a content of the filler in the resin layer is 20% by mass or more and 65% by mass or less, A ratio of a thickness (μm) of the resin layer to an average particle diameter (μm) of the filler (thickness (μm) of resin layer / average particle diameter (μm) of filler) is more than 5.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a decorative sheet and a decorated resin molded product. [Background technology]

[0002] Decorative resin molded products in which a decorative sheet is laminated onto the surface of a resin molded product are used for vehicle interior parts, building interior materials, home appliance housings, etc. A known method for molding such decorative resin molded products is the insert molding method (see, for example, Patent Document 1), in which the decorative sheet is first molded into a three-dimensional shape using a vacuum forming mold, the molded decorative sheet is inserted into an injection molding mold, and a resin in a fluid state is injected into the mold to integrate the resin and the decorative sheet.

[0003] In recent years, with the diversification of consumer needs, there has been a demand for decorative resin moldings with various designs. In order to meet these diversifying consumer needs, there is a need to develop decorative resin moldings that have a design feel and a texture based on the uneven surface shape.

[0004] In the manufacture of a decorated resin molded product having a textured surface, for example, a decorative sheet with a textured surface formed in advance is used. However, when a decorated resin molded product is manufactured using a decorative sheet with a textured surface, there is a problem in that it is difficult to maintain the textured surface, as the textured surface is deformed or lost due to heat or pressure when the decorative sheet is subjected to injection molding or the preforming (vacuum forming) that precedes the injection molding. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-322501 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, in recent years, there has been a demand for the development of decorated resin molded products that have a design feel and a tactile sensation based on the uneven surface shape. However, when manufacturing decorated resin molded products using a decorative sheet with an uneven shape, there is a problem in that it is difficult to maintain the uneven shape, as the uneven shape can be deformed or lost due to heat and pressure when the decorative sheet is subjected to injection molding or the preliminary molding (vacuum molding) that precedes it.

[0007] In order to ensure the formability of the decorative sheet while suppressing deformation or disappearance of the uneven shape of the decorative sheet during molding, the inventors of the present disclosure considered laminating a base layer containing a thermoplastic resin and a resin layer containing polypropylene with a high melting peak temperature onto the decorative sheet.

[0008] However, after further investigation, the inventors of the present disclosure found that although the use of a base layer containing a thermoplastic resin and a resin layer containing polypropylene with a high melting peak temperature prevents deformation and disappearance of the uneven shape during molding of the decorative sheet, they faced a new problem in that warping occurs after molding of the decorative sheet due to the difference in thermal shrinkage between the base layer and the resin layer.

[0009] In light of these circumstances, the present disclosure has as its main object to provide a novel decorative sheet having an uneven outer surface, which maintains the uneven shape even after molding and suppresses warping after molding. Another object of the present disclosure is to provide a decorated resin molded product using the decorative sheet. [Means for solving the problem]

[0010] The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. As a result, they found that in a decorative sheet having, in order from the outside, a resin layer and a base layer, at least the outer surface of the resin layer has an uneven shape, the outer surface of the resin layer has an uneven shape, the base layer is made of a thermoplastic resin, the resin layer is made of polypropylene having a peak melting temperature of 150°C or higher and a filler, the filler content in the resin layer is set within a predetermined range, and further, the ratio of the thickness (μm) of the resin layer to the average particle size (μm) of the filler (thickness (μm) of the resin layer (μm) / average particle size (μm) of the filler) is set to a predetermined ratio or higher, the uneven shape of the decorative sheet is favorably maintained even after molding, and warping after molding is suppressed. The present disclosure was completed based on this finding and through further research.

[0011] That is, the present disclosure provides the inventions of the following aspects. Item 1. A decorative sheet having, in order from the outside, at least a resin layer and a base layer, The outer surface of the decorative sheet has an uneven shape, The outer surface of the resin layer has an uneven shape, the substrate layer contains a thermoplastic resin, the resin layer contains polypropylene having a melting peak temperature of 150°C or higher and a filler, the content of the filler in the resin layer is 20% by mass or more and 65% by mass or less, A decorative sheet in which the ratio of the thickness (μm) of the resin layer to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer / average particle diameter (μm) of the filler) is greater than 5. Item 2. The decorative sheet according to Item 1, wherein the filler has an average particle size of 5 μm or more and 15 μm or less. Item 3. The decorative sheet according to Item 1, wherein the resin film constituting the resin layer has a dimensional change rate of 1.5% or less when the temperature changes from 130°C to 25°C. Item 4. The decorative sheet according to any one of Items 1 to 3, further comprising a design layer on the outside of the resin layer. Item 5. The decorative sheet according to any one of Items 1 to 4, further comprising a surface protection layer on the outside of the resin layer. Item 6. The decorative sheet according to any one of Items 1 to 5, further comprising a primer layer. Item 7. The decorative sheet according to any one of Items 1 to 6, further comprising an adhesive layer. Item 8. A decorated resin molded product comprising, in order from the outside, at least a resin layer, a base layer, and a molded resin layer, The outer surface of the decorated resin molded product has an uneven shape, The outer surface of the resin layer has an uneven shape, the substrate layer contains a thermoplastic resin, the resin layer contains polypropylene having a melting peak temperature of 150°C or higher and a filler, the content of the filler in the resin layer is 20% by mass or more and 65% by mass or less, A decorated resin molded product, wherein the ratio of the thickness (μm) of the resin layer to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer / average particle diameter (μm) of the filler) is greater than 5. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a novel decorative sheet having an uneven shape on its outer surface, in which the uneven shape is favorably maintained even after molding and warping after molding is suppressed. Furthermore, according to the present disclosure, it is also possible to provide a decorated resin molded product using the decorative sheet. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a decorative sheet according to the present disclosure. [Figure 2] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a decorative sheet according to the present disclosure. [Figure 3] 1 is a schematic diagram of a cross-sectional structure of one embodiment of a decorated resin molded product according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1.Decorative sheet The decorative sheet of the present disclosure is a decorative sheet comprising, from the outside in order, at least a resin layer and a base layer, the outer surface of the decorative sheet (the surface opposite the base layer) having an uneven shape, the outer surface of the resin layer also having an uneven shape, the base layer containing a thermoplastic resin, the resin layer containing polypropylene having a peak melting temperature of 150°C or higher and a filler, the content of the filler in the resin layer being 20% ​​by mass or more and 65% by mass or less, and the ratio of the thickness (μm) of the resin layer to the average particle size (μm) of the filler (thickness (μm) of the resin layer / average particle size (μm) of the filler) being greater than 5. By having these configurations, the decorative sheet of the present disclosure is able to favorably maintain the uneven shape of the outer surface even during molding, and can be favorably vacuum molded under low-temperature conditions that suppress warping after molding.

[0015] The decorative sheet of the present disclosure will be described in detail below with reference to FIGS. 1 to 3. In this specification, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, 2 to 15 mm means 2 mm or greater and 15 mm or less. In the numerical ranges described in this disclosure in stages, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Separately described upper and lower limits, upper and lower limits, or lower and upper and lower limits may be combined to form a numerical range. In the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. In this specification, "(meth)acrylate" means "acrylate or methacrylate," and similar terms have similar meanings.

[0016] Laminated structure and physical properties of decorative sheets 1 and 2, the decorative sheet 10 of the present disclosure has an uneven outer surface and includes, from the outside, at least a resin layer 1 and a base layer 2. The base layer 2 contains a thermoplastic resin. The resin layer 1 contains polypropylene having a peak melting temperature of 150°C or higher and a filler.

[0017] As shown in Figures 1 and 2, the decorative sheet 10 of the present disclosure may have, in addition to the resin layer 1 and the base layer 2, one or more other layers, such as a design layer 3, a surface protection layer 4, a primer layer 5, and an adhesive layer 6, at any position depending on the function to be imparted to the decorative sheet or the decorated resin molded product.

[0018] The laminate structure of the decorative sheet of the present disclosure may be: Laminated structure consisting of a substrate layer and a resin layer; A laminated structure consisting of a base layer, a resin layer, and a design layer stacked in this order; A laminated structure consisting of a base layer, a resin layer, a design layer, and a surface protection layer in this order; A laminated structure consisting of a base layer, a resin layer, a design layer, a primer layer, and a surface protection layer in this order; A laminated structure consisting of a base layer, adhesive layer, resin layer, design layer, and surface protection layer in this order; A laminated structure consisting of a base layer, adhesive layer, resin layer, design layer, primer layer, and surface protection layer in this order; A laminated structure in which a base layer / adhesive layer / resin layer / primer layer / design layer / primer layer / surface protection layer are laminated in this order; A laminated structure in which a base layer / adhesive layer / primer layer / resin layer / primer layer / design layer / primer layer / surface protection layer are laminated in this order; A laminated structure in which adhesive layer / base layer / adhesive layer / primer layer / resin layer / primer layer / design layer / primer layer / surface protection layer are laminated in this order; Examples include:

[0019] Fig. 1 shows a schematic cross-sectional view of an example of a decorative sheet having a laminated structure of a base material layer, a resin layer, a design layer, and a surface protective layer in this order, as one embodiment of the laminated structure of the decorative sheet of the present disclosure. Fig. 2 shows a schematic cross-sectional view of an example of a decorative sheet having a laminated structure of a base material layer, an adhesive layer, a primer layer, a resin layer, a primer layer, a design layer, a primer layer, and a surface protective layer in this order, as one embodiment of the laminated structure of the decorative sheet of the present disclosure.

[0020] In the decorative sheet 10, the ratio of the total thickness of the base layer 2, resin layer 1, optional design layer 3, optional surface protection layer 4, optional primer layer 5, and optional adhesive layer 6 to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0021] As a specific example, when the decorative sheet 10 of the present disclosure includes a resin layer 1, a base layer 2, a design layer 3, a surface protective layer 4, and a primer layer 5, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the decorative sheet 10 is, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, when the decorative sheet 10 of the present disclosure is a laminate including a resin layer 1, a base layer 2, a design layer 3, a surface protective layer 4, a primer layer 5, and an adhesive layer 6, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the decorative sheet 10 can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0022] From the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the decorative sheet of the present disclosure has a retention rate of the uneven shape of the outer surface after molding, measured by the following method, of preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more, with the upper limit being, for example, 100%.

[0023] (Retention rate of uneven shape after molding of decorative sheet) The depth of the concave portions of the textured outer surface of the decorative sheet was measured. Both sides of the decorative sheet were then heated to 160°C using a non-contact radiant heater to soften it. Next, a male vacuum forming mold measuring 150 mm in length, 100 mm in width, and 3 mm in height was prepared. The base layer side of the decorative sheet was placed in contact with the mold, and the decorative sheet was vacuum-formed (3 mm in depth). After trimming the molded portion, it was injection-molded (temperature 260°C, pressure 130 MPa, injection resin polycarbonate-ABS) into a 3 mm thick plate. The depth of the concave portions was then measured again. The depth of the concave portions was defined as the difference between the apex of the concave portion and the base of the concave portion immediately adjacent to it. The depth of the concave portions was measured using a scanning white light interference microscope. The change in the depth of the concave portions before and after insert molding was used to calculate the retention rate of the concave portions. Measurements were performed at three locations, and the average value was used.

[0024] Furthermore, from the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the decorative sheet of the present disclosure preferably has a warpage after molding of 6 mm or less, more preferably 3 mm or less, as measured by the following method.

[0025] (Warping of decorative sheet after molding) Both sides of the decorative sheet are heated to 160°C using a non-contact radiant heater to soften it. Next, a male mold for vacuum forming, measuring 150mm in length, 100mm in width, and 3mm in height, is prepared, and the base layer side of the decorative sheet is placed in contact with the mold, and the decorative sheet is vacuum formed. When the formed part is trimmed to a 10cm square, warping occurs toward the resin layer side. The sheet is placed on a level desk, and the height of the four corners from the desk surface is measured, and the average warping value is calculated.

[0026] Decorative sheet uneven shape The decorative sheet of the present disclosure has an uneven shape formed on its outer surface. The uneven shape may be formed only on the layer (surface layer) constituting the outer surface of the decorative sheet of the present disclosure, but it is preferable that a corresponding uneven shape is also formed on layers (inner layers) inside the surface layer. That is, the recesses of the uneven shape on the outer surface of the decorative sheet may reach the inner layers (e.g., the design layer 3, the resin layer 1, the primer layer 5, the adhesive layer 6, the base layer 2) located below the surface layer (e.g., the surface protective layer 4, etc.). From the viewpoint of effectively suppressing the loss, deformation, etc. of the uneven shape during injection molding of the decorative sheet, it is preferable that the recesses of the uneven shape on the outer surface reach the inner layers. When a corresponding uneven shape is also formed on layers inside the surface layer, it is preferable that the uneven shape is formed on the surface of the resin layer 1 opposite the base layer 2 side. That is, it is preferable that the uneven shape on the outer surface of the resin layer 1 has a shape corresponding to the uneven shape on the outer surface of the decorative sheet. On the other hand, it is preferable that the surface of the resin layer 1 facing the base material layer 2 does not have such an uneven shape and is flat. It is preferable that the surface of the base material layer 2 does not have such an uneven shape and is flat.

[0027] The decorative sheet of the present disclosure may have a design expressed by a concave-convex shape on the outer surface. Examples of designs expressed by the concave-convex shape include a hairline pattern, a wood grain pattern, and a geometric pattern (dots, stripes, carbon, etc.). The height of the convex portions, the width of the convex portions, the pitch between adjacent convex portions, the width of the concave portions, etc., of the concave-convex shape may be appropriately set depending on the design impression to be imparted to the decorated resin molded product.

[0028] In the decorative sheet of the present invention, the uneven shape may be formed in at least a partial region. That is, in the decorative sheet of the present invention, the uneven shape of the outer surface may be formed in a partial region or may be formed in the entire region. The uneven shape can be formed, for example, by embossing the outer surface of the laminate (laminate sheet) that constitutes the decorative sheet.

[0029] Each layer that makes up the decorative sheet [Resin layer 1] The resin layer 1 is a layer provided together with the base layer 2 containing a thermoplastic resin in order to suppress warping of the decorative sheet after molding while maintaining the uneven shape of the outer surface of the decorative sheet after molding.

[0030] In the decorative sheet of the present disclosure, the outer surface of the resin layer 1 has an uneven shape. The uneven shape of the outer surface of the resin layer 1 can be a shape corresponding to the uneven shape of the outer surface of the decorative sheet, and such a shape is preferred.

[0031] The resin layer 1 contains polypropylene having a melting peak temperature of 150°C or higher and a filler. The filler content in the resin layer 1 is in the range of 20% by mass or higher and 65% by mass or lower. Furthermore, the ratio of the thickness (μm) of the resin layer 1 to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer 1 / average particle diameter (μm) of the filler) is greater than 5.

[0032] To more effectively achieve the effects of the present invention, the melting peak temperature of the polypropylene contained in the resin layer 1 is preferably about 150°C or higher, more preferably about 160°C or higher, and preferably about 180°C or lower, more preferably about 170°C or lower. Preferred ranges include about 150 to 180°C, about 150 to 170°C, about 160 to 180°C, and about 160 to 170°C. The melting peak temperature of the polypropylene is a value measured by differential scanning calorimetry (DSC), and specific measurements are described in the Examples. By satisfying this melting peak temperature, the decorative sheet of the present disclosure can be imparted with the flexibility required during molding. Furthermore, collapse of the uneven shape due to the heat of molding is suppressed, allowing a good shape to be maintained.

[0033] From the viewpoint of more suitably exerting the effects of the invention of the present disclosure, the filler content in the resin layer 1 is preferably about 25% by mass or more, more preferably about 30% by mass or more, and is preferably about 65% by mass or less, more preferably about 60% by mass or less, with preferred ranges including about 20 to 60% by mass, about 25 to 65% by mass, about 25 to 60% by mass, about 30 to 65% by mass, and about 30 to 60% by mass. By satisfying these contents, the decorative sheet of the present disclosure has a low coefficient of linear expansion, and the difference in dimensional change from the base layer due to molding heat is reduced, thereby suppressing warpage.

[0034] Furthermore, from the viewpoint of more suitably exerting the effects of the present invention, the ratio of the thickness (μm) of the resin layer 1 to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer / average particle diameter (μm) of the filler) is greater than 5, preferably 10 or more, and preferably about 30 or less, more preferably about 20 or less. Preferred ranges include greater than 5 and about 30 or less, greater than 5 and about 20 or less, 10 or more and about 30 or less, and 10 or more and about 20 or less.

[0035] To more effectively achieve the effects of the present invention, the average particle size (μm) of the filler is preferably at least about 2 μm, more preferably at least about 5 μm, and preferably no more than about 15 μm, more preferably no more than about 10 μm, with preferred ranges being about 2 to 15 μm, about 2 to 10 μm, about 5 to 15 μm, and about 5 to 10 μm. By satisfying these average particle sizes, the decorative sheet of the present disclosure can prevent deterioration of design due to filler exposure during molding and suppress dimensional change during molding. In the present invention, the average particle size of the filler is the average value of the particle sizes of 30 random filler particles measured by observing the cross section of the resin layer 1 with a scanning electron microscope (SEM). Specific measurements are described in the Examples.

[0036] Furthermore, from the viewpoint of more suitably exerting the effects of the presently disclosed invention, the thickness (μm) of the resin layer 1 is preferably about 50 μm or more, more preferably about 100 μm or more, and is preferably about 400 μm or less, more preferably about 200 μm or less, with preferred ranges including about 50 to 400 μm, about 50 to 200 μm, about 100 to 400 μm, and about 100 to 200 μm.

[0037] From the viewpoint of more suitably exerting the effects of the present invention, the polypropylene contained in resin layer 1 and having a melting peak temperature of 150°C or higher is preferably homopolypropylene (h-pp), polypropylene block copolymer (b-pp, for example, a block copolymer of propylene and ethylene), etc., and among these, homopolypropylene and polypropylene block copolymer are preferred, with homopolypropylene being more preferred. The polypropylene contained in resin layer 1 and having a melting peak temperature of 150°C or higher may be of only one type or of two or more types.

[0038] From the viewpoint of more suitably exerting the effects of the present invention, the proportion of polypropylene having a melting peak temperature of 150°C or higher in the resin contained in resin layer 1 is preferably about 50% by mass or higher, more preferably about 60% by mass or higher, even more preferably about 70% by mass or higher, even more preferably about 80% by mass or higher, even more preferably about 90% by mass or higher, even more preferably about 95% by mass or higher, and is also preferably about 100% by mass.

[0039] The resin layer 1 may further contain, as another resin, at least one of polypropylene having a melting peak temperature of less than 150°C (for example, a random copolymer of polypropylene (r-pp) or a random copolymer of propylene and ethylene), and a resin other than polypropylene. Examples of resins other than polypropylene include poly-α-olefins such as ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, and 4-methyl-1-pentene; ethylene-α-olefin copolymer elastomers such as ethylene-butene copolymer elastomer (EBR) and ethylene-hexene copolymer elastomer (EHR); styrene-butadiene-styrene triblock copolymer elastomer (SBS); styrene-isoprene-styrene triblock copolymer elastomer (SIS); and styrene-ethylene copolymer elastomers. Examples of suitable resins include styrene-based elastomers such as ethylene-butylene copolymer elastomer (SEB), styrene-ethylene-propylene copolymer elastomer (SEP), and styrene-ethylene-butylene-styrene copolymer elastomer (SEBS). Resins other than those listed above may also be included within a range that does not impair the effects of the present embodiment. The proportion of these other resins in the resin contained in resin layer 1 is preferably about 50% by mass or less, more preferably about 40% by mass or less, even more preferably about 30% by mass or less, even more preferably about 20% by mass or less, even more preferably about 10% by mass or less, even more preferably about 5% by mass or less, and even preferably about 0% by mass.

[0040] The filler contained in the resin layer 1 is preferably at least one of inorganic particles and inorganic fibers. The inorganic particles are not particularly limited as long as they are particles formed from an inorganic compound, and examples thereof include clay mineral particles typified by talc and feldspar, silica particles, calcium carbonate particles, barium sulfate particles, alumina particles, and glass balloon particles. Examples of inorganic fibers include glass fibers. One type of filler may be used alone, or two or more types may be used in combination.

[0041] The resin layer 1 may further contain additives such as common antioxidants, ultraviolet absorbers, radical trapping agents (HALS), dispersants, flame retardants, antistatic agents, etc. The content of additives in the resin layer 1 is, for example, about 5% by mass or less, preferably about 3% by mass or less, more preferably about 1% by mass or less, and may be about 0% by mass.

[0042] The resin layer 1 is made of a resin film containing polypropylene and a filler, and is preferably made of a polypropylene film containing a filler.

[0043] To more effectively achieve the effects of the present invention, the absolute value of the dimensional change rate of the resin film constituting the resin layer 1 when the temperature changes from 130°C to 25°C is preferably about 1.5% or less, more preferably about 1.2% or less, and even more preferably about 0.9% or less. The lower limit is about 0%, about 0.2%, or about 0.4%, and preferred ranges include about 0-1.5%, about 0-1.2%, about 0.2-1.5%, about 0.2-1.2%, about 0.2-0.9%, about 0.4-1.5%, about 0.4-1.2%, and about 0.4-0.9%. By satisfying this dimensional change rate, the decorative sheet of the present disclosure can suppress warping due to the heat of forming during vacuum forming. The dimensional change rate of the resin film constituting the resin layer 1 is a value measured by the following method. Note that the dimensional change rate will be a negative value if the resin film shrinks and becomes shorter due to a temperature change from 130° C. to 25° C. For example, if the absolute value of the dimensional change rate of the resin film constituting the resin layer 1 when the temperature changes from 130° C. to 25° C. is 0 to 1.5%, this means that the dimensional change rate is 0 to ±1.5%.

[0044] [Dimensional change rate of resin film constituting resin layer] The dimensional change rate of the resin layer was measured using a thermomechanical analyzer under environmental conditions compliant with JIS-K7100 using the following method. The resin layer was cut into 5mm x 20mm pieces, fixed to a jig with a 10mm chuck distance, and placed in the analyzer. Under a nitrogen atmosphere and a load of 30mN, the temperature was raised from -10°C to 135°C at a rate of 10°C / min., held at 135°C for 5 minutes, and then lowered from 135°C to 25°C at a rate of 10°C / min. During the temperature drop, the dimensions were measured at 135°C and 25°C, and the dimensional change rate was calculated from the change. Measurements were performed on three samples, and the average of the three measurements (N=3) was used.

[0045] In order to improve adhesion to the layer disposed thereon, the base layer 2 may be subjected to a physical or chemical surface treatment such as an oxidation method or a roughening method on one or both sides, as in the case of the resin layer 1 described above.

[0046] The base layer 2 may be colored with a colorant, or may not be colored. The base layer 2 may be colorless and transparent, colored and transparent, or translucent. The colorant used in the base layer 2 is not particularly limited and is the same as that used in the resin layer 1.

[0047] As described above, when a concave-convex shape corresponding to the concave-convex shape of the outer surface is also formed in a layer that is more inward than the surface layer that constitutes the surface of the decorative sheet, it is preferable that the concave-convex shape is formed on the surface of the resin layer 1 opposite to the base layer 2. On the other hand, it is preferable that the concave-convex shape is not formed on the surface of the resin layer 1 facing the base layer 2, and that the surface of the resin layer 1 facing the base layer 2 is flat.

[0048] [Base material layer 2] The base layer 2 is a resin sheet (resin film) that serves as a support in the decorative sheet of the present disclosure.

[0049] The base layer 2 contains a thermoplastic resin. From the viewpoint of more suitably exerting the effects of the present disclosure, specific examples of the thermoplastic resin contained in the base layer 2 include acrylonitrile-butadiene-styrene resin (hereinafter sometimes referred to as "ABS resin"), acrylonitrile-styrene-acrylic acid ester resin (hereinafter sometimes referred to as "ASA resin"), acrylic resin, polyolefins such as polypropylene and polyethylene, polycarbonate, polyvinyl chloride, and polyethylene terephthalate (PET). Among these, ABS resin, polycarbonate, and polypropylene are preferred. The base layer 2 may be formed of a single-layer sheet of these resins, or may be formed of a multi-layer sheet of the same or different resins.

[0050] The Vicat softening temperature of the thermoplastic resin is preferably about 80 to 155°C, more preferably about 90 to 140°C, and even more preferably about 105 to 125°C.

[0051] The flexural modulus of the base layer 2 is not particularly limited. For example, when the decorative sheet of the present disclosure is integrated with a molding resin by insert molding, the flexural modulus of the base layer 2 of the decorative sheet of the present disclosure at 25°C is 500 to 4,000 MPa, preferably 750 to 3,000 MPa. Here, the flexural modulus at 25°C is a value measured in accordance with JIS K7171. When the flexural modulus at 25°C is 500 MPa or more, the decorative sheet has sufficient rigidity, and even when subjected to insert molding, the surface properties and moldability are further improved. Furthermore, when the flexural modulus at 25°C is 3,000 MPa or less, sufficient tension can be applied during roll-to-roll production, making sagging less likely to occur, allowing overlapping printing of patterns without misalignment, resulting in good pattern registration.

[0052] In order to improve adhesion to the layer disposed thereon, the base layer 2 may be subjected to a physical or chemical surface treatment such as an oxidation method or a roughening method on one or both sides, as in the case of the resin layer 1 described above.

[0053] The base layer 2 may be subjected to a known treatment such as forming an adhesive layer.

[0054] Furthermore, the base layer 2 may be colored with a colorant, or may not be colored, as long as the surface resistance value is satisfied. The base layer 2 may be colorless and transparent, colored and transparent, or translucent. The colorant used in the base layer 2 is not particularly limited and may be the same as that used in the resin layer 1.

[0055] The thickness of the base layer 2 is set appropriately depending on the application of the decorative sheet, the molding method for integrating it with a molding resin, etc., but is typically about 25 to 1000 μm, or about 50 to 700 μm. More specifically, when the decorative sheet of the present disclosure is subjected to insert molding, the thickness of the base layer 2 is typically about 50 to 1000 μm, preferably about 100 to 700 μm, and more preferably about 100 to 500 μm.

[0056] [Design layer 3] The design layer 3 is a layer provided for the purpose of imparting design to the decorative sheet. In the decorative sheet 10 of the present disclosure, the design layer 3 is a layer that is observed from the side opposite the base layer 2 (the side opposite the molded resin layer 7 side of the decorated resin molded product 20, from which the design of the decorated resin molded product 20 can be observed). The design layer 3 is provided outside the base layer 2. It is preferable that the design layer 3 be provided outside the resin layer 1.

[0057] Examples of the design layer 3 include a pattern layer having a pattern, and a concealing layer (undercoat layer) having no pattern and intended to suppress color changes and variations in the base layer 2.

[0058] The design layer 3 can be, for example, a layer (ink layer) on which a desired design is formed using an ink composition. The ink composition used to form the design layer 3 is a mixture of a binder, a colorant such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a hardener, etc., as appropriate.

[0059] The binder used in the ink composition is not particularly limited, but examples thereof include polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, polyester resin, polyamide resin, butyral resin, polystyrene resin, nitrocellulose resin, cellulose acetate resin, etc. These binders may be used alone or in combination of two or more.

[0060] The colorant used in the ink composition is not particularly limited as long as the design layer 3 satisfies the above-mentioned surface resistance value, but examples include inorganic pigments such as carbon black (ink), iron black, titanium white, antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; organic pigments or dyes such as quinacridone red, isoindolinone yellow, and phthalocyanine blue; metal pigments consisting of scaly foil flakes such as aluminum and brass; and pearlescent pigments consisting of scaly foil flakes such as titanium dioxide-coated mica and basic lead carbonate. In the decorative sheet of the present disclosure, the design layer 3 preferably contains at least one of a carbon pigment and an aluminum pigment.

[0061] The pattern formed by the design layer 3 is not particularly limited, and examples include wood grain patterns, stone patterns that imitate the surface of rock such as marble patterns (e.g., travertine marble patterns), fabric patterns that imitate fabric or cloth-like patterns, tile patterns, brickwork patterns, etc., and may also be patterns that combine these, such as marquetry or patchwork, or may be a single solid color (so-called solid color). These patterns are formed by multicolor printing using the usual process colors of yellow, red, blue, and black, but can also be formed by multicolor printing using spot colors, which is performed by preparing plates for each color that makes up the pattern.

[0062] The thickness of the design layer 3 is not particularly limited, but is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more, and is preferably 20 μm or less, more preferably 15 μm or less, and even more preferably 10 μm or less, with a preferred range being approximately 1 to 20 μm.

[0063] [Hidden layer] In the design layer 3, the concealing layer (base layer) is a layer that is provided as needed between the resin layer 1 and the surface protection layer 4, between the resin layer 1 and the primer layer 5 if a primer layer 5 is provided, or between the resin layer 1 and the pattern layer if a pattern layer is provided in the design layer 3, for the purpose of suppressing color changes and variations in the resin layer 1.

[0064] The concealing layer is provided to prevent the resin layer from adversely affecting the color tone and pattern of the decorative sheet, and is therefore generally formed as an opaque layer.

[0065] The hiding layer is formed using an ink composition obtained by appropriately mixing a binder with a colorant such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a curing agent, etc. The ink composition for forming the hiding layer is appropriately selected from those used for the decorative layer described above.

[0066] The concealing layer is usually set to a thickness of about 1 to 20 μm, and is preferably formed as a so-called solid print layer.

[0067] The hiding layer is formed by a conventional printing method such as gravure printing, offset printing, silk screen printing, printing by transfer from a transfer sheet, or inkjet printing; or a conventional coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, or reverse roll coating.

[0068] [Surface protection layer 4] The surface protection layer 4 is a layer that is provided as needed to protect the surface of the decorated resin molded product.

[0069] The material constituting the surface protective layer 4 is not particularly limited as long as it functions to protect the surface of the decorated resin molded product, and examples thereof include thermoplastic resins, thermosetting resins, and ionizing radiation curable resins. Among these, from the viewpoint of suitably imparting the function of a surface protective layer to the decorated resin molded product, it is preferable that the surface protective layer 4 be composed of a cured product of an ionizing radiation curable resin composition. The ionizing radiation curable resin used to form the surface protective layer 4 will be described in detail below.

[0070] (ionizing radiation curable resin) The ionizing radiation-curable resin used to form the surface protective layer 4 is a resin that crosslinks and cures upon exposure to ionizing radiation. Specific examples include a mixture of at least one of prepolymers, oligomers, and monomers, each of which has a polymerizable unsaturated bond or epoxy group in its molecule. Here, ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Typically, ultraviolet (UV) or electron beams (EB) are used, but ionizing radiation also includes other types of electromagnetic waves, such as X-rays and gamma rays, as well as charged particle beams, such as alpha rays and ion beams. Among ionizing radiation-curable resins, electron beam-curable resins are suitable for use in forming the surface protective layer 4 because they can be made solvent-free, do not require a photopolymerization initiator, and exhibit stable curing properties.

[0071] The monomer used as the ionizing radiation curable resin is preferably a (meth)acrylate monomer having a radical polymerizable unsaturated group in the molecule, and among these, a polyfunctional (meth)acrylate monomer is preferred. The polyfunctional (meth)acrylate monomer may be a (meth)acrylate monomer having two or more (difunctional or more), preferably three or more (trifunctional or more) polymerizable unsaturated bonds in the molecule. Specific examples of the polyfunctional (meth)acrylate include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylol propionate, and the like. Examples of suitable monomers include propane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. These monomers may be used alone or in combination of two or more.

[0072] The oligomer used as the ionizing radiation-curable resin is preferably a (meth)acrylate oligomer having a radically polymerizable unsaturated group in the molecule, and particularly preferably a polyfunctional (meth)acrylate oligomer having two or more (bifunctional or more) polymerizable unsaturated bonds in the molecule. Examples of polyfunctional (meth)acrylate oligomers include polycarbonate (meth)acrylate, acrylic silicone (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polybutadiene (meth)acrylate, silicone (meth)acrylate, and oligomers having a cationically polymerizable functional group in the molecule (e.g., novolac epoxy resin, bisphenol epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc.). Here, the polycarbonate (meth)acrylate is not particularly limited as long as it has a carbonate bond in the polymer main chain and a (meth)acrylate group at the end or side chain. For example, it can be obtained by esterifying a polycarbonate polyol with (meth)acrylic acid. The polycarbonate (meth)acrylate may be, for example, a urethane (meth)acrylate having a polycarbonate skeleton. The urethane (meth)acrylate having a polycarbonate skeleton can be obtained, for example, by reacting a polycarbonate polyol with a polyvalent isocyanate compound and a hydroxy (meth)acrylate. The acrylic silicone (meth)acrylate can be obtained by radical copolymerization of a silicone macromonomer with a (meth)acrylate monomer. The urethane (meth)acrylate can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate compound with (meth)acrylic acid. Epoxy (meth)acrylate can be obtained, for example, by reacting (meth)acrylic acid with the oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolac type epoxy resin to esterify it.Carboxyl-modified epoxy (meth)acrylates obtained by partially modifying this epoxy (meth)acrylate with a dibasic carboxylic acid anhydride can also be used. Polyester (meth)acrylates can be obtained, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends, obtained by condensation of a polycarboxylic acid and a polyhydric alcohol, with (meth)acrylic acid, or by esterifying the terminal hydroxyl groups of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid with (meth)acrylic acid. Polyether (meth)acrylates can be obtained by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid. Polybutadiene (meth)acrylates can be obtained by adding (meth)acrylic acid to the side chain of a polybutadiene oligomer. Silicone (meth)acrylates can be obtained by adding (meth)acrylic acid to the end or side chain of a silicone having a polysiloxane bond in its main chain. These oligomers may be used alone or in combination of two or more.

[0073] Among the above-mentioned ionizing radiation curable resins, polycarbonate (meth)acrylate is preferably used from the viewpoint of obtaining superior three-dimensional moldability while further improving the appearance of the design, abrasion resistance, and moldability. It is also preferable to use a combination of polycarbonate (meth)acrylate and urethane (meth)acrylate.

[0074] The surface protective layer 4 may also contain at least one of inorganic particles and organic particles. In the surface protective layer 4, the inorganic particles and organic particles mainly have the function of reducing the gloss of the surface protective layer 4. When the surface protective layer 4 contains inorganic particles or organic particles, these particles are dispersed in the surface protective layer 4.

[0075] The inorganic particles are not particularly limited as long as they are particles formed from an inorganic compound, and examples thereof include silica particles, calcium carbonate particles, barium sulfate particles, alumina particles, and glass balloon particles. One type of inorganic particle may be used alone, or two or more types may be used in combination. The particle diameter of the inorganic particles is, for example, about 0.5 μm or more, preferably about 1 μm or more, and preferably about 20 μm or less, more preferably about 10 μm or less. Preferred particle diameter ranges for the inorganic particles include about 0.5 to 20 μm, about 0.5 to 10 μm, about 1 to 20 μm, and about 1 to 10 μm. In the present invention, the particle diameter of the inorganic particles is the average particle diameter of 30 random inorganic particles measured by observing the cross section of the surface protective layer 4 with a scanning electron microscope (SEM).

[0076] When the surface protective layer 4 contains inorganic particles, the content of the inorganic particles is not particularly limited, but is preferably at least about 1 part by mass, more preferably at least about 10 parts by mass, and preferably at most about 60 parts by mass, more preferably at most about 40 parts by mass, per 100 parts by mass of the ionizing radiation curable resin. Preferred ranges for the content of the inorganic particles include about 1 to 60 parts by mass, about 1 to 40 parts by mass, about 10 to 60 parts by mass, and about 10 to 40 parts by mass, per 100 parts by mass of the ionizing radiation curable resin. The inorganic particles may be used alone or in combination of two or more types.

[0077] The organic particles are not particularly limited as long as they are particles formed from a resin, and examples thereof include urethane beads, nylon beads, acrylic beads, silicone beads, styrene beads, melamine beads, urethane acrylic beads, polyester beads, and polyethylene beads. One type of organic particle may be used alone, or two or more types may be used in combination. The particle diameter of the organic particles is approximately 0.5 μm or more, preferably approximately 1 μm or more, and is preferably approximately 30 μm or less, and more preferably approximately 20 μm or less. Preferred particle diameter ranges for the organic particles include approximately 0.5 to 30 μm, approximately 0.5 to 20 μm, approximately 1 to 30 μm, and approximately 1 to 20 μm. The particle diameter of the organic particles is a value measured by the same method as for the inorganic particles described above.

[0078] When the surface protective layer 4 contains organic particles, the content of the organic particles is not particularly limited, but is preferably at least about 1 part by mass, more preferably at least about 10 parts by mass, and is preferably at most about 200 parts by mass, more preferably at most 150 parts by mass, relative to 100 parts by mass of the ionizing radiation curable resin. Preferred ranges for the content of the organic particles include about 1 to 200 parts by mass, about 1 to 150 parts by mass, about 10 to 200 parts by mass, and more preferably about 10 to 150 parts by mass, relative to 100 parts by mass of the ionizing radiation curable resin.

[0079] When the surface protective layer 4 contains at least one of inorganic particles and organic particles, some of these particles may protrude from the surface of the surface protective layer 4, or the particles may be buried inside the surface protective layer 4.

[0080] (Other added ingredients) Various additives can be blended into the surface protective layer 4 depending on the desired physical properties of the surface protective layer 4. Examples of such additives include weather resistance improvers such as ultraviolet absorbers and light stabilizers, abrasion resistance improvers, polymerization inhibitors, crosslinking agents, infrared absorbers, adhesion improvers, leveling agents, thixotropy-imparting agents, coupling agents, plasticizers, antifoaming agents, fillers, solvents, and colorants. These additives can be appropriately selected from commonly used additives. Furthermore, reactive ultraviolet absorbers and light stabilizers having a polymerizable group such as a (meth)acryloyl group in the molecule can also be used as the ultraviolet absorber and light stabilizer.

[0081] (Formation of surface protective layer 4) The surface protective layer 4 is formed, for example, by preparing an ionizing radiation curable resin composition containing an ionizing radiation curable resin (containing the aforementioned inorganic particles, organic particles, various additives, etc., as necessary), applying the composition, and curing it. The viscosity of the ionizing radiation curable resin composition may be any viscosity that allows the formation of an uncured resin layer by the application method described below.

[0082] In the present disclosure, the prepared resin composition is applied by a known method such as gravure coating, bar coating, roll coating, reverse roll coating, or comma coating, preferably gravure coating, to form an uncured resin layer.

[0083] The uncured resin layer thus formed is irradiated with ionizing radiation such as electron beams or ultraviolet rays to cure the uncured resin layer and form the surface protective layer 4. When electron beams are used as the ionizing radiation, the acceleration voltage can be appropriately selected depending on the resin used and the thickness of the layer, but is typically 70 kV or more and 300 kV or less. The preferred range of the acceleration voltage is 70 to 300 kV.

[0084] In electron beam irradiation, the higher the acceleration voltage, the greater the penetration ability, so when a resin that is easily deteriorated by electron beam irradiation is used below the surface protective layer 4, the acceleration voltage is selected so that the penetration depth of the electron beam is substantially equal to the thickness of the surface protective layer 4. This makes it possible to prevent excess electron beam irradiation of layers located below the surface protective layer 4, and minimize deterioration of each layer due to excess electron beams.

[0085] The irradiation dose is preferably an amount at which the crosslinking density of the surface protective layer 4 is saturated, and is usually 5 kGy or more (0.5 Mrad or more), preferably 10 kGy or more (1 Mrad or more), and usually 300 kGy or less (30 Mrad or less), preferably 50 kGy or less (5 Mrad or less). The preferred range of the irradiation dose is selected from the ranges of 5 to 300 kGy (0.5 to 30 Mrad), 5 to 50 kGy (0.5 to 5 Mrad), 10 to 300 kGy (1 to 30 Mrad), and 10 to 50 kGy (1 to 5 Mrad).

[0086] Furthermore, the electron beam source is not particularly limited, and various electron beam accelerators such as Cockcroft-Walton type, Van de Graaf type, resonant transformer type, insulating core transformer type, linear type, dynamitron type, and high frequency type can be used.

[0087] When ultraviolet rays are used as the ionizing radiation, light rays containing ultraviolet rays with a wavelength of 190 to 380 nm may be emitted. The ultraviolet source is not particularly limited, but examples thereof include high-pressure mercury lamps, low-pressure mercury lamps, metal halide lamps, and carbon arc lamps.

[0088] The surface protective layer 4 thus formed may be subjected to treatment to impart functions such as hard coating function, anti-fogging coating function, anti-fouling coating function, anti-glare coating function, anti-reflection coating function, ultraviolet shielding coating function, and infrared shielding coating function by adding various additives.

[0089] The thickness of the surface protective layer 4 is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more, and is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less, with a preferred range being approximately 1 to 50 μm.

[0090] [Primer layer 5] The primer layer 5 is a layer that is provided as needed for the purpose of increasing adhesion between layers, etc. The primer layer 5 is provided, for example, between the resin layer 1 and the base layer 2, between the resin layer 1 and the design layer 3, or between the surface protection layer 4 and the design layer 3.

[0091] The primer composition constituting the primer layer 5 preferably uses a binder resin such as polyurethane, (meth)acrylic resin, (meth)acrylic-urethane copolymer, vinyl chloride-vinyl acetate copolymer, polyester, butyral resin, chlorinated polypropylene, chlorinated polyethylene, etc., and these resins can be used alone or in combination. Among these, polyurethane, (meth)acrylic resin, and (meth)acrylic-urethane copolymer are preferred.

[0092] Polyurethanes that use a polyol (polyhydric alcohol) as the base and an isocyanate as the crosslinking agent (curing agent) can be used. Polyols that have two or more hydroxyl groups in the molecule, such as polyester polyols, polyethylene glycols, polypropylene glycols, acrylic polyols, and polyether polyols, can be used. Examples of the isocyanates that can be used include polyisocyanates that have two or more isocyanate groups in the molecule, aromatic isocyanates such as 4,4-diphenylmethane diisocyanate, and aliphatic (or alicyclic) isocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Polyurethanes can also be made by mixing polyurethane with butyral resin.

[0093] From the viewpoint of improving the formability of the decorative sheet 10, when forming the primer layer 5, it is preferable to use a combination of an acrylic polyol or a polyester polyol as the polyol and hexamethylene diisocyanate or 4,4-diphenylmethane diisocyanate as the crosslinking agent, and it is particularly preferable to use a combination of an acrylic polyol and hexamethylene diisocyanate.

[0094] Examples of the (meth)acrylic resin include a homopolymer of a (meth)acrylic acid ester, a copolymer of two or more different (meth)acrylic acid ester monomers, or a copolymer of a (meth)acrylic acid ester and another monomer. Specifically, (meth)acrylic resins made of a homopolymer or copolymer containing a (meth)acrylic acid ester, such as polymethyl(meth)acrylate, polyethyl(meth)acrylate, polypropyl(meth)acrylate, polybutyl(meth)acrylate, a methyl(meth)acrylate-butyl(meth)acrylate copolymer, an ethyl(meth)acrylate-butyl(meth)acrylate copolymer, an ethylene-methyl(meth)acrylate copolymer, or a styrene-methyl(meth)acrylate copolymer, are preferably used.

[0095] As the (meth)acrylic-urethane copolymer, for example, an acrylic-urethane (polyester urethane) block copolymer is preferred. As the curing agent, the various isocyanates mentioned above are used. If desired, the acrylic-urethane (polyester urethane) block copolymer preferably has an acrylic / urethane ratio (mass ratio) of 1 / 9 or more, more preferably 2 / 8 or more. Furthermore, the acrylic / urethane ratio (mass ratio) is preferably 9 / 1 or less, more preferably 8 / 2 or less.

[0096] The thickness of the primer layer 5 is not particularly limited, but is, for example, 0.5 μm or more, preferably 1 μm or more, and is preferably 20 μm or less, more preferably 5 μm or less, and preferred ranges include about 0.5 to 20 μm, and about 1 to 5 μm.

[0097] The primer layer 5 is formed using a primer composition by a common coating method such as gravure coating, gravure reverse coating, gravure offset coating, spinner coating, roll coating, reverse roll coating, kiss coating, wheel coating, dip coating, solid coating by silk screen, wire bar coating, flow coating, comma coating, flow coating, brush coating, spray coating, or transfer coating. Here, the transfer coating method is a method in which a coating film of the primer layer 5 is formed on a thin sheet (film substrate), and then the primer layer is coated on the surface of the target layer in the decorative sheet.

[0098] [Adhesive layer 6] The adhesive layer 6 is also a layer that is provided as needed for the purpose of increasing the adhesion between layers.

[0099] Like the primer layer 5, the adhesive layer 6 is provided, for example, between the resin layer 1 and the base layer 2. Although not shown, in the decorative sheet 10, the adhesive layer 6 can also be a layer that forms the surface of the base layer 2 opposite to the resin layer 1 side. This can improve the adhesion between the decorative sheet 10 and the molded resin layer 7.

[0100] The adhesive layer 6 is formed using, for example, a thermoplastic resin or a curable resin.

[0101] Examples of thermoplastic resins used to form the adhesive layer 6 include rubber-based resins, acrylic-based resins, epoxy-based resins, and urethane-based resins. Of these, urethane-based resins are preferred. By using urethane-based resins, stronger adhesive strength can be obtained, and a decorative sheet with excellent flexibility can be provided.

[0102] Urethane resin is a polyurethane that uses polyol (polyhydric alcohol) as the main component and isocyanate as the crosslinking agent (curing agent).

[0103] The polyol has two or more hydroxyl groups in the molecule, and examples of the polyol include polyethylene glycol, polypropylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, acrylic polyol, polyester polyol, and polyether polyol.

[0104] The isocyanate used in the present invention is one that is commonly used in the production of polyurethane. Examples of the isocyanate include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, lysine ester triisocyanate, 1,4,8-triisocyanato octane, 1,3,6-triisocyanato hexane, and 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanato methyl octane; 1,3-cyclopentene diisocyanate; Alicyclic compounds such as isocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (common name: isophorone diisocyanate), 1,3,5-triisocyanatocyclohexane, 1,3,5-trimethylisocyanatocyclohexane, and 2-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2,2,1)heptane Examples of polyisocyanates that can be used include aralkyl polyisocyanates such as polyisocyanates, 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene and 1,3,5-triisocyanatomethylbenzene, and aromatic polyisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, triphenylmethane-4,4',4"-triisocyanate and 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate, as well as derivatives of these polyisocyanates. Two or more of these polyisocyanates may be used in combination. Of these polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, aralkyl polyisocyanates, and polyisocyanate derivatives thereof are preferably used. These polyisocyanates are excellent in safety, hygiene, and weather resistance.

[0105] The thickness of the adhesive layer 6 is not particularly limited, but is, for example, 0.5 μm or more, preferably 1 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, and preferred ranges include about 0.5 to 20 μm, and about 1 to 10 μm.

[0106] 2. Decorative resin molded products The decorated resin molded product of the present disclosure is formed by integrating the molded resin layer 7 with the decorative sheet 10 of the present disclosure.

[0107] 3, the decorated resin molded product 20 of the present disclosure is a decorated resin molded product obtained by laminating the decorative sheet 10 of the present disclosure on a molded resin layer 7. That is, the decorated resin molded product 20 of the present disclosure is a decorated resin molded product including, in order from the outside, at least a resin layer 1, a base layer 2, and a molded resin layer 7, the outer surface of the decorated resin molded product has an uneven shape, the outer surface of the resin layer 1 has an uneven shape, the base layer 2 contains a thermoplastic resin, the resin layer 1 contains polypropylene having a peak melting temperature of 150°C or higher and a filler, the content of the filler in the resin layer 1 is 20% by mass or more and 50% by mass or less, and the ratio of the thickness (μm) of the resin layer 1 to the average particle size (μm) of the filler (thickness (μm) of the resin layer 1 / average particle size (μm) of the filler) is greater than 5.

[0108] FIG. 3 shows a cross-sectional structure of one embodiment of the decorated resin molded product of the present disclosure.

[0109] The decorated resin molded product 20 of the present disclosure can be manufactured by a method including a step of forming a molded resin layer 7 by injecting a resin into the decorative sheet 10 of the present disclosure. Specifically, the method of manufacturing the decorated resin molded product of the present disclosure includes a step of statically charging the decorative sheet of the present disclosure and fixing the decorative sheet to a mold, and a step of injecting a resin into the mold to integrate the decorative sheet 10 and the molded resin layer 7.

[0110] As a molding method for integrating the decorative sheet of the present disclosure with the molded resin layer, various injection molding methods such as insert molding, blow molding, gas injection molding, etc. Among these, insert molding is particularly suitable for the present disclosure.

[0111] In the insert molding method, first, in the vacuum forming step, the decorative sheet of the present disclosure is vacuum-formed in advance into the surface shape of the molded article (offline preforming) using a vacuum forming mold, and then excess portions are trimmed as necessary to obtain a molded sheet. This molded sheet is inserted into an injection mold, the injection mold is closed, and a fluid resin is injected into the mold and solidified. The decorative sheet is integrated with the outer surface of the resin molded article at the same time as injection molding, thereby producing a decorated resin molded article.

[0112] More specifically, the decorated resin molded product of the present disclosure is produced by an insert molding method including the following steps.

[0113] a vacuum forming step of forming the decorative sheet of the present disclosure into a three-dimensional shape in advance using a vacuum forming mold; A step of trimming excess portions of the vacuum-formed decorative sheet to obtain a molded sheet; and This is the process in which the molded sheet obtained in the previous process is inserted into an injection mold (metal die), the injection mold is closed, and the resin in a fluid state is injected into the mold to integrate the resin and the molded sheet.

[0114] In the vacuum forming step of the insert molding method, the decorative sheet may be heated and formed. The heating temperature is not particularly limited and may be selected appropriately depending on the type of resin constituting the decorative sheet, the thickness of the decorative sheet, etc., but can be, for example, about 100 to 180°C, preferably about 120 to 160°C. In the integration step, the temperature of the resin in a fluid state is not particularly limited, but can usually be about 180 to 280°C, preferably about 200 to 260°C.

[0115] In the decorated resin molded product of the present disclosure, the molded resin layer may be formed from a molding resin selected according to the intended use. The molding resin may be a thermoplastic resin or a thermosetting resin.

[0116] Examples of thermoplastic resins used as molding resins include polyolefins such as polyethylene and polypropylene, ABS resins, styrene resins, polycarbonate resins, acrylic resins, and vinyl chloride resins, but in the present disclosure, polyolefins such as polyethylene and polypropylene are particularly preferred because the base layer 2 of the decorative sheet 10 is formed from polyolefins. These thermoplastic resins may be used alone or in combination of two or more.

[0117] Furthermore, examples of the thermosetting resin used as the molding resin include urethane resin, epoxy resin, etc. These thermosetting resins may be used alone or in combination of two or more.

[0118] The decorated resin molded product of the present disclosure can be used, for example, as interior or exterior materials for vehicles such as automobiles; fixtures such as baseboards and moldings; window frames, door frames and other fittings; interior materials for buildings such as walls, floors and ceilings; housings for home appliances such as television sets and air conditioners; containers, etc. [Example]

[0119] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0120] [Manufacturing decorative sheets] <Examples 1-7 and Comparative Examples 1-5> A primer layer (acrylic / urethane resin, 1 μm thick), a design layer (acrylic resin, 2 μm thick), and a primer layer (acrylic / urethane resin, 1 μm thick) were sequentially laminated on one side of a resin layer (each a 100 μm thick polypropylene film) having the melting peak temperature (°C), resin type, filler type, filler content (%), and filler particle size (μm) listed in Table 1. Next, a primer layer (urethane resin, 1 μm thick), an adhesive layer (urethane resin, 10 μm thick), and a substrate layer listed in Table 1 were laminated on the other side of the resin layer. Gravure printing was used to laminate the primer layer, design layer, and adhesive layer. The substrate layer was laminated to the adhesive layer surface of the resin layer.

[0121] Next, the primer layer side of the resulting laminate was embossed to form a textured pattern on the primer layer. An embossing plate with a stripe pattern and an embossing depth of 60 μm was used. Next, to form a surface protective layer, an ionizing radiation-curable resin composition (a mixture of 80 parts by mass of bifunctional polycarbonate acrylate (weight-average molecular weight 10,000) and 20 parts by mass of hexafunctional urethane acrylate oligomer (weight-average molecular weight 6,000)) was gravure-coated to a thickness of 10 μm after curing to form an uncured resin layer. This uncured resin layer was cured by irradiating it with an accelerating voltage of 165 kV and an exposure dose of 50 kGy (5 Mrad), forming a surface protective layer with a textured pattern. The textured pattern of the surface protective layer corresponded to the textured pattern of the adjacent primer layer. Furthermore, the recesses of the textured pattern of the decorative sheet reached the opposite side of the resin layer from the base layer side, and the surface of the resin layer opposite the base layer side had a textured pattern. On the other hand, the surface of the resin layer facing the base layer was flat, and both surfaces of the base layer were also flat. By the above procedure, a decorative sheet was produced in which, from the outside, a surface protective layer, a primer layer, a design layer, a primer layer, a resin layer, a primer layer, an adhesive layer, and a base layer were laminated in this order. As shown in Table 1, the resin layers of Examples 1 to 7 and Comparative Examples 1 to 3 and 5 were polypropylene films containing fillers, and the resin layer of Comparative Example 4 was a polypropylene film containing no fillers.

[0122] [Peak melting temperature of resin layer] The melting peak temperature of the resin layer is a value measured by the following method. Measurements were performed under environmental conditions conforming to JIS-K7100 using a differential scanning calorimeter (Shimadzu Corporation, DSC-60APlus) under conditions conforming to JIS-K7121. After placing a polypropylene film, which is the resin layer, in a sample pan, the temperature was increased from -20°C to 200°C at a rate of 20°C / min in a nitrogen atmosphere, and the endothermic peak temperature was measured. Three polypropylene films of each example and comparative example were prepared, and measurements were performed on each, and the average value of the three measurements was used (N=3).

[0123] [Average particle size of filler] The average particle size of the filler is a value measured by the following method. The cross section of the resin layer 1 was observed with a scanning electron microscope (SEM) and measured, and the particle diameter was calculated from the average value of the particle diameters of 30 randomly selected fillers (particles).

[0124] [Dimensional change rate of resin film constituting resin layer] The dimensional change rate of each polypropylene film used as the resin layer was measured using the following method. The results are shown in Table 1. Measurements were performed using a thermomechanical analyzer (TMA7100, manufactured by Hitachi High-Technologies Corporation) under environmental conditions conforming to JIS-K7100. The resin layer was cut into a size of 5 mm x 20 mm, fixed to a jig with a chuck distance of 10 mm, and placed in the analyzer. Under a nitrogen atmosphere and a load of 30 mN, the temperature was increased from -10°C to 135°C at a rate of 10°C / min., held at 135°C for 5 minutes, and then decreased from 135°C to 25°C at a rate of 10°C / min. During the temperature decrease process, the dimensions were measured at 135°C and 25°C, and the dimensional change rate was calculated from the change. Negative values ​​indicate shrinkage. Three polypropylene films were prepared for each example and comparative example, and measurements were performed on each. The average value of the three measurements was used (N=3).

[0125] [Evaluation of decorative sheets] The decorative sheets were evaluated as follows, and the results are shown in Table 1.

[0126] (Moldability of decorative sheets) Both sides of the decorative sheet were heated to 160°C using a non-contact radiant heater to soften it. Next, a vacuum forming mold was prepared, and the decorative sheet was placed so that the design layer side was in contact with the mold. The decorative sheet was vacuum formed so that it conformed to the internal shape of the mold. The vacuum forming mold was a female mold with an opening of 50mm x 50mm and a depth of 15mm, and all corners were rounded with a radius of R = 5mm. After forming, the decorative sheet was most stretched at the corners of the mold, with an elongation rate of 150%. This point is called the maximum stretched area. Note that an elongation rate of 100% means that the decorative sheet has been stretched to twice its length before forming. The formed decorative sheet was visually inspected and evaluated according to the following criteria.

[0127] <Evaluation criteria> A: The maximum extension of the decorative sheet can follow the shape of the vacuum forming mold, and no cracks or other abnormalities in appearance occur. B: The maximum extension part of the decorative sheet is unable to follow the shape of the vacuum forming mold, and abnormalities in appearance such as cracks have occurred.

[0128] (Retention rate of uneven shape after insert molding of decorative sheet) The depth of the concave portions of the textured outer surface of the decorative sheet was measured. Both sides of the decorative sheet were then heated to 160°C using a non-contact radiant heater to soften it. Next, a male vacuum forming mold measuring 150 mm in length, 100 mm in width, and 3 mm in height was prepared. The base layer side of the decorative sheet was placed in contact with the mold, and the decorative sheet was vacuum-formed (3 mm in depth). After trimming, the molded portion was injection-molded (temperature 260°C, pressure 130 MPa, injection resin polycarbonate-ABS) into a 3 mm-thick plate. The depth of the concave portions was then measured again. The depth of the concave portions was defined as the difference between the apex of the concave portion and the base of the concave portion immediately adjacent to it. The depth of the concave portions was measured using a scanning white light interference microscope (Hitachi High-Tech Corporation, VS1330). The maintenance rate of the concave portions was calculated from the change in the depth of the concave portions before and after insert molding. Measurements were taken at three locations, and the average value was used.

[0129] (Warping of decorative sheet after molding) Both sides of the decorative sheet were heated to 160°C using a non-contact radiant heater to soften it. Next, a male mold for vacuum forming measuring 150mm in length, 100mm in width, and 3mm in height was prepared, and the decorative sheet was placed so that the base layer side was in contact with the mold, and the decorative sheet was vacuum formed. When the molded part was trimmed to a 10cm square, warping occurred toward the resin layer side. The sheet was placed on a horizontal desk and the height of the four corners from the desk surface was measured, and the average warping value was calculated. <Evaluation criteria> A: The average height of the warp is 3 mm or less B: Average height of warpage is greater than 3 mm and less than 6 mm C: Average height of warpage is 6 mm or more

[0130] [Table 1] [Explanation of symbols]

[0131] 1 resin layer 2 Base material layer 3 Design layer 4 Surface protective layer 5 Primer layer 6 Adhesive layer 7 Molding resin layer 10 Decorative sheet 20 Decorative resin moldings

Claims

1. A decorative sheet including, in order from the outside, at least a resin layer and a base layer, The outer surface of the decorative sheet has an uneven shape, The outer surface of the resin layer has an uneven shape, the substrate layer contains a thermoplastic resin, the resin layer contains polypropylene having a melting peak temperature of 150°C or higher and a filler, the content of the filler in the resin layer is 20% by mass or more and 65% by mass or less, A decorative sheet, wherein the ratio of the thickness (μm) of the resin layer to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer / average particle diameter (μm) of the filler) is greater than 5.

2. The decorative sheet according to claim 1 , wherein the filler has an average particle size of 5 μm or more and 15 μm or less.

3. 2. The decorative sheet according to claim 1, wherein the resin film constituting the resin layer has a dimensional change rate of 1.5% or less when the temperature changes from 130°C to 25°C.

4. The decorative sheet according to any one of claims 1 to 3, further comprising a design layer on the outside of the resin layer.

5. The decorative sheet according to any one of claims 1 to 3, further comprising a surface protection layer on the outside of the resin layer.

6. The decorative sheet according to any one of claims 1 to 3, further comprising a primer layer.

7. The decorative sheet according to any one of claims 1 to 3, further comprising an adhesive layer.

8. A decorated resin molded product including, in order from the outside, at least a resin layer, a base layer, and a molded resin layer, The outer surface of the decorated resin molded product has an uneven shape, The outer surface of the resin layer has an uneven shape, the substrate layer contains a thermoplastic resin, the resin layer contains polypropylene having a melting peak temperature of 150°C or higher and a filler, the content of the filler in the resin layer is 20% by mass or more and 65% by mass or less, A decorated resin molded product, wherein the ratio of the thickness (μm) of the resin layer to the average particle diameter (μm) of the filler (thickness (μm) of the resin layer / average particle diameter (μm) of the filler) is greater than 5.

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