Decorative sheet

Abstract

A decorative sheet (20) comprises: a substrate layer (1), a pattern layer (2) provided on a surface (1a) side of the substrate layer (1), and a thermoplastic resin layer (3) provided on a surface (2a) side of the pattern layer (2). A test piece with a width of 8 mm is prepared from the decorative sheet (20), and when the storage modulus of the prepared test piece is measured under the conditions of an initial chuck distance of 10.77 mm, a starting temperature of 30° C., an end temperature of 150° C., a heating rate of 5° C. / min, and a measurement frequency of 1.0 Hz, the ratio of the difference between the second storage modulus when the decorative sheet (20) changes from a glassy region to a transition region and the third storage modulus when the decorative sheet (20) changes from the transition region to a rubbery flat region to the difference between the first storage modulus and the second storage modulus at an ambient temperature of 30° C. is set to be 3.5 times or less.

Description

Technical Field

[0001] The present invention relates to a decorative sheet. Background Art

[0002] Conventionally, for example, a decorative sheet having a base layer and a thermoplastic resin layer provided on the surface side of the base layer has been proposed (see, for example, Patent Document 1). When the decorative sheet described in Patent Document 1 is used, the decorative sheet is inserted into a mold cavity, the inserted decorative sheet is preformed, and at the same time, a flowing resin is filled into the mold cavity to solidify the resin, and the solidified resin and the preformed decorative sheet are integrated to produce a molded product.

[0003] However, in the decorative sheet described in Patent Document 1, if the decorative sheet is not sufficiently heated or softened during pre-molding, the decorative sheet cannot sufficiently follow the mold, or the decorative sheet is molded in a state of low fluidity, and the thickness of the sheet after pre-molding becomes uneven, which may cause whitening or cracks at the edge. On the other hand, if the decorative sheet is overheated during pre-molding, crystal melting or foaming may occur.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5055707 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a decorative sheet having a wide allowable temperature range during molding and excellent moldability.

[0009] Means for solving problems

[0010] In order to solve the above-mentioned problems, one aspect of the present invention is a decorative sheet comprising (a) a substrate layer, and (b) a thermoplastic resin layer provided on the surface side of a pattern layer, wherein (c) a test piece having a width of 8 mm is prepared from the decorative sheet, and when the storage modulus of the prepared test piece is measured at a starting temperature of 30°C, an ending temperature of 150°C, and a temperature increase rate of 5°C / min, and at an initial chuck distance of 10.77 mm and a measurement frequency of 1.0 Hz, the ratio of the difference between the second storage modulus when the decorative sheet changes from a glassy region to a transition region and the third storage modulus when the decorative sheet changes from the transition region to a rubbery flat region to the difference between the first storage modulus and the second storage modulus when the ambient temperature is 30°C is set to be less than 3.5 times.

[0011] Effects of the Invention

[0012] According to the present invention, a decorative sheet having a wide allowable temperature range during molding and excellent moldability can be provided.

[0013] BRIEF DESCRIPTION OF THE DRAWINGS

[0014] [ Figure 1 ] is a cross-sectional view showing a decorative sheet according to the first and second embodiments.

[0015] [ Figure 2 ] is a graph showing the relationship between ambient temperature and storage modulus.

[0016] [ Figure 3 ] is a perspective view showing a molded product formed by a decorative sheet.

[0017] [ Figure 4 ] is a cross-sectional view showing a decorative sheet for automobile interior according to a third embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, a decorative sheet according to an embodiment of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following embodiments, and modifications such as design changes may be added based on the knowledge of those skilled in the art, and the addition of such modifications is also within the scope of the present invention. In addition, in order to facilitate understanding, each of the drawings is appropriately exaggerated.

[0019] 1. First embodiment: Decorative sheet

[0020] 1-1. Composition

[0021] 1-2. Method for manufacturing molded product

[0022] 1-3. Examples

[0023] 2. Second Embodiment: Decorative Sheet

[0024] 2-1. Issues

[0025] 2-2. Composition

[0026] 2-3. Example

[0027] 3. Third embodiment: Decorative sheet for automobile interior

[0028] 3-1.Topic

[0029] 3-2. Composition

[0030] 3-3. Method for producing decorative sheet for automobile interior

[0031] 3-4. Example

[0032] <1. First Embodiment: Decorative Sheet>

[0033] [1-1. Structure]

[0034] like Figure 1 As shown, the decorative sheet 20 according to the first embodiment includes: a substrate layer 1, a pattern layer 2 provided on the surface 1a side of the substrate layer 1, and a thermoplastic resin layer 3 provided on the surface 2a side of the pattern layer 2. The total thickness of the decorative sheet 20 according to the first embodiment is not particularly limited, but from the viewpoint of the surface strength and handleability of the decorative sheet 20, it is preferably 255 μm or more and 550 μm or less, and more preferably 275 μm or more and 550 μm or less. In addition, from the viewpoint of the moldability and surface strength of the decorative sheet 20, the ratio of the thickness of the thermoplastic resin layer 3 to the substrate layer 1 is preferably 1:1.5 to 1:7, and more preferably 1:2.5 to 1:6. In particular, from the viewpoint of the stability of the sheet thickness of the flat portion and the corner portion and the appearance abnormality, it is more preferable to satisfy the following two: the total thickness of the decorative sheet 20 is 275 μm or more and 550 μm or less, and the ratio of the thickness of the thermoplastic resin layer 3 to the substrate layer 1 is 1:2.5 to 1:6. As a lamination method of the base material layer 1, the pattern layer 2, the thermoplastic resin layer 3, etc., for example, any of heat lamination, dry lamination, hot melt lamination, and extrusion lamination can be used.

[0035] It should be noted that, although the present embodiment shows an example in which the decorative sheet 20 is formed by sequentially stacking the base material layer 1, the pattern layer 2, and the thermoplastic resin layer 3, other structures may be adopted. For example, the base material layer 1, the thermoplastic resin layer 3, and the pattern layer 2 may be sequentially stacked.

[0036] (Base material layer)

[0037] The substrate layer 1 is a sheet-like layer that serves as the base of the decorative sheet 20. As the material of the substrate layer 1, for example, at least one selected from polyester and a copolymerized synthetic resin (ABS) of acrylonitrile, butadiene and styrene can be used. As the ABS resin, for example, a polymer blend type of styrene-chloronitrile copolymer and NBR (nitrile rubber) can be used; a graft type obtained by graft copolymerizing styrene and acrylonitrile in the coexistence of BR (polybutadiene rubber) or SBR (styrene / butadiene rubber) latex. From the viewpoint of easy elongation, the content ratio of butadiene is preferably 20% by weight or more and 50% by weight or less. As polyester, for example, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate can be used. The substrate layer 1 is set as a single layer.

[0038] Furthermore, the thickness of the base material layer 1 is preferably not less than 196 μm and not more than 413 μm.

[0039] (Pattern layer)

[0040] The pattern layer 2 is a layer for giving the decorative sheet 20 a design derived from a pattern. The pattern layer 2 is formed by using a printing ink or a coating agent. There are no particular restrictions on the printing ink, etc., and the same materials as the printing ink used for the pattern layer in the previous decorative sheet can be used. For example, acrylic ink can be used. As an acrylic ink, for example, a two-liquid curing type urethane resin ink formed by blending an isocyanate curing agent into an acrylic polyol medium can be used. In addition, as a printing method, for example, a gravure printing method or an offset printing method can be used. In addition, as a pattern, any pattern can be used, for example, a wood grain pattern, a stone grain pattern, a cloth grain pattern, a cork pattern, an abstract pattern, a geometric pattern, etc.; or a combination of two or more of these, etc.

[0041] (Thermoplastic resin layer)

[0042] As a material of the thermoplastic resin layer 3, at least one selected from acrylic resin, polyolefin resin, and vinyl chloride resin can be used. In addition, the thermoplastic resin layer 3 may be a single layer or a multi-layer.

[0043] It should be noted that, in view of the increasing concern of society about environmental issues in recent years, it is not desirable to use thermoplastic resins containing chlorine (halogen) such as vinyl chloride resins, but it is desirable to use non-halogen thermoplastic resins. In particular, polyolefin resins are desirable as non-halogen thermoplastic resins from the viewpoints of various physical properties, processability, versatility, and economy.

[0044] In addition, as polyolefin resin, the most preferred for general use is polypropylene resin, i.e., homopolymer or copolymer with propylene as the main component. For example, homopolypropylene resin, random polypropylene resin, block polypropylene resin, etc. can be used alone or appropriately blended, or resins obtained by further appropriately blending random polypropylene to them can be used. In addition, copolymers containing olefin monomers other than propylene can also be used, for example, propylene-α-olefin copolymers having a polypropylene crystal part and containing 15 mol% or more of α-olefins (preferably ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, one or more comonomers) with a carbon number of 2 to 20 can be used. In addition, low-density polyethylene, ethylene-α-olefin copolymers, ethylene-propylene copolymer rubbers, ethylene-propylene-non-conjugated diene copolymer rubbers, styrene-butadiene copolymers or their hydrogenated products, which are usually used to soften polypropylene resins, can be appropriately added.

[0045] Furthermore, the thickness of the thermoplastic resin layer 3 is preferably not less than 50 μm and not more than 144 μm.

[0046] (Other layers)

[0047] Similar to conventional decorative sheets, the decorative sheet 20 may also include, for example, a surface protection layer 4 and an adhesive layer 5 in addition to the base material layer 1, the pattern layer 2, and the thermoplastic resin layer 3. The surface protection layer 4 is provided on the surface 3a side of the thermoplastic resin layer 3. In addition, the adhesive layer 5 is provided between the base material layer 1 and the pattern layer 2. Figure 1 In the embodiment, an adhesive layer 5, a pattern layer 2, a thermoplastic resin layer 3 and a surface protection layer 4 are sequentially laminated on a surface 1a of a base material layer 1.

[0048] In addition, the outermost surface of the decorative sheet 20 (i.e., the surface 4a of the surface protection layer 4) may be appropriately provided with a concave-convex pattern 6 formed by embossing. As the concave-convex pattern 6, for example, a pattern synchronized with the pattern of the patterned layer 2 or a pattern asynchronous with the pattern may be used.

[0049] (Surface protection layer)

[0050] The surface protection layer 4 is a layer provided as required to protect the surface of the decorative sheet 20. There are no particular restrictions on the material of the surface protection layer 4, and the same material as that used for the surface protection layer in the previous decorative sheet can be used. For example, acrylic urethane resins, ionizing radiation curing resins, and fluororesins can be used. As acrylic urethane resins, for example, a reaction product obtained by using an acrylic polyol compound as a main agent and an isocyanate compound as a curing agent can be used. In addition, as an ionizing radiation curing resin, for example, a composition having at least one of a prepolymer, an oligomer, and a monomer having a polymerizable unsaturated bond such as a (meth) acryloyl group as a main component can be used, wherein the polymerizable unsaturated bond such as the (meth) acryloyl group has the property of undergoing a cross-linking reaction through irradiation with ionizing radiation. As ionizing radiation, for example, electron beams and ultraviolet rays can be used. In addition, as a fluororesin, for example, PVDF (polyvinylidene fluoride) can be used.

[0051] (Adhesive layer)

[0052] The adhesive layer 5 is a layer provided as needed to bond the base material layer 1 and the thermoplastic resin layer 3 together. The material of the adhesive layer 5 is not particularly limited, and the same material (adhesive) as that used for the adhesive layer in the conventional decorative sheet can be used. For example, a heat sealant obtained by blending vinyl chloride acetate resin with acrylic resin at a ratio of 60:40 to 70:30 can be used.

[0053] (Concave and convex pattern)

[0054] The concavoconvex pattern 6 is provided as required to give a three-dimensional design sense to the surface of the decorative sheet 20. As the concavoconvex pattern 6, any concavoconvex shape can be used, for example, a wood grain duct shape, a stone grain shape, a cloth grain shape, an abstract pattern shape, a Japanese paper shape, a suede shape, a leather shape, a satin grain shape, a sand grain shape, a hairline shape, or a combination thereof, etc. In addition, as a method for forming the concavoconvex pattern 6, for example, a double embossing method performed before lamination of the thermoplastic resin layer 3, after lamination, or simultaneously with lamination, an extrusion lamination simultaneous embossing method, etc. can be used.

[0055] (Storage modulus)

[0056] In the decorative sheet 20 according to the first embodiment, various parameters of the decorative sheet 20 are adjusted so that the storage modulus satisfies the following conditions. The conditions to be satisfied are as follows: a test piece with a width of 8 mm is prepared from the decorative sheet 20, and when the ambient temperature is changed at a starting temperature of 30°C, an ending temperature of 150°C, and a heating rate of 5°C / min, and the storage modulus of the prepared test piece is measured in such a manner that the initial chuck distance is 10.77 mm and the measurement frequency is 1.0 Hz, as shown in FIG. Figure 2 As shown, the ratio R (= (G2-G3) / (G1-G2)) of the difference (G2-G3) between the second storage modulus G2 when the decorative sheet 20 changes from the glassy region to the transition region and the third storage modulus G3 when the decorative sheet 20 changes from the transition region to the rubbery flat region relative to the difference (G1-G2) between the first storage modulus G1 and the second storage modulus G2 when the ambient temperature is 30°C is less than a multiple of a specified value. The specified value (for example) is preferably 3.5, more preferably 2.5, and most preferably 2.0. In addition, the lower limit of the ratio R is preferably greater than 0.1, more preferably greater than 0.5, and most preferably greater than 1.0. When the ratio R is less than 0.1, the elastic modulus is low, and thus the scratch resistance may be reduced, or it may not be sufficiently softened even when heated, and poor molding may occur.

[0057] It should be noted that, as a method for calculating the second storage modulus G2, for example, a method can be used in which, based on the intersection 7 of the approximate straight line of the temperature and storage modulus in the glassy region and the approximate straight line of the temperature and storage modulus in the transition region, the storage modulus corresponding to the intersection 7 is calculated. In addition, as a method for calculating the third storage modulus G3, for example, a method can be used in which, based on the intersection 8 of the approximate straight line of the temperature and storage modulus in the transition region and the approximate straight line of the temperature and storage modulus in the rubbery flat region, the storage modulus corresponding to the intersection 8 is calculated.

[0058] [1-2. Method for producing molded product]

[0059] By laminating the decorative sheet 20 according to the first embodiment on an adherend made of resin, etc., a molded product decorated with the adherend can be produced. As a method for producing the molded product, for example, IML (Insert Molding Laminate) molding method, injection molding and lamination method, TOM (Three Dimension Overlay Method) molding method can be used.

[0060] For example, the IML molding method is a method in which, after vacuum molding or pressure vacuum molding is performed and the surface portion of the molded product is formed using the decorative sheet 20, the decorative sheet 20 forming the surface portion is assembled into an injection molding mold, and resin is injected to the back side of the decorative sheet 20 to make the resin (adherent) and the decorative sheet 20 become one, thereby producing a molded product. In addition, for example, the TOM molding method is a method in which vacuum molding or pressure vacuum molding is performed to laminate the decorative sheet 20 on the previously formed resin to make the resin (adherent) and the decorative sheet 20 become one, thereby producing a molded product.

[0061] As described above, the decorative sheet 20 according to the first embodiment is a sheet including the base layer 1 , the pattern layer 2 provided on the surface 1 a of the base layer 1 , and the thermoplastic resin layer 3 provided on the surface 2 a of the pattern layer 2 . Then, a test piece with a width of 8 mm is prepared from the decorative sheet 20, and when the storage elastic modulus of the prepared test piece is measured at a starting temperature of 30°C, an end temperature of 150°C, a heating rate of 5°C / min, an initial chuck distance of 10.77 mm, and a measurement frequency of 1.0 Hz, the ratio R (=(G2-G3) / (G1-G2)) of the difference (G2-G3) between the second storage modulus G2 when the decorative sheet 20 changes from the glassy region to the transition region and the third storage modulus G3 when the decorative sheet 20 changes from the transition region to the rubbery flat region to the difference (G1-G2) between the first storage modulus G1 and the second storage modulus G2 at an ambient temperature of 30°C is set to 3.5 times or less. Thus, a decorative sheet 20 having a wide temperature range (molding temperature range) allowed during molding and excellent moldability can be provided. In addition, since the moldability is excellent, whitening and cracking of the edge, crystal melting, foaming, etc. are unlikely to occur, and the molded product can be appropriately designed.

[0062] Incidentally, if the ratio R (= (G2-G3) / (G1-G2)) is greater than 3.5 times, the elastic modulus will change dramatically when the temperature of the transition zone is reached, and the sheet may break due to overheating. In addition, if the decorative sheet 20 cannot be heated sufficiently due to concerns about the occurrence of sheet breakage caused by overheating, the decorative sheet 20 may not be able to follow the mold sufficiently or may whiten due to insufficient heating. That is, the temperature range allowed during molding (the range of molding temperatures) may become narrower. In addition, when the ambient temperature T2 at which the storage modulus is "G2" is reached, the heat resistance of the product may decrease. On the other hand, if the ratio R (= (G2-G3) / (G1-G2)) is less than 3.5 times, the transition zone is wider to a certain extent, and the ambient temperature T2 at which the storage modulus reaches "G2" will not be too low, so a decorative sheet 20 with heat resistance and excellent moldability can be obtained.

[0063] In addition, when the ratio R is 3.5 times or less but greater than 3.0 times, there is a concern that the sheet may break or the followability may be insufficient as in the case of greater than 3.5 times, so it is still necessary to perform molding in a somewhat narrow temperature range, and when the temperature condition fluctuates for some reason, disadvantages may also occur. On the contrary, when the ratio R is 3.0 times or less, the storage modulus in the transition region changes gradually, thereby achieving an effect of reducing the possibility of disadvantages.

[0064] In addition, when the ratio R is 3.0 times or less but greater than 2.0 times, the film thickness change after molding becomes large, and there may be disadvantages such as "substrate transparency" in which the substrate to which the molded product is attached becomes transparent. On the contrary, when the ratio R is 2.0 times or less, the film thickness change after molding can be reduced, and the effect of substrate transparency being difficult to occur can be obtained.

[0065] [1-3. Example]

[0066] Hereinafter, examples and comparative examples of the decorative sheet 20 according to the first embodiment will be described. It should be noted that the present invention is not limited to the following examples.

[0067] (Example 1)

[0068] First, a PMMA film (manufactured by Mitsubishi Chemical Co., Ltd.) was prepared as a thermoplastic resin layer 3. The thickness of the PMMA film was set to 125 μm. Next, a pattern layer 2 made of acrylic ink and an adhesive layer 5 made of acrylic acid-vinyl chloride acetate were sequentially laminated on one surface of the PMMA film by gravure printing to produce a printed sheet. Then, the produced printed sheet and a substrate layer 1 made of an ABS substrate were integrated into two layers by a thermal lamination method. The thickness of the ABS substrate was set to 375 μm. Thus, a decorative sheet 20 was produced.

[0069] Next, the decorative sheet 20 is subjected to TOM molding using a TOM molding machine ("NGF-0406-T" manufactured by "Fuse Vacuum Co., Ltd."). Specifically, first, the mold and the decorative sheet 20 are placed in a box, and after evacuation, the decorative sheet 20 is heated to a set temperature (100°C, 110°C, 120°C) using a heater, thereby performing pre-molding. Then, after the heating of the decorative sheet 20 is completed, a pressure of 0.3MPa is applied to form a molded product. Next, after air cooling, the molded product is removed from the mold. In TOM molding, as Figure 3 As shown, the decorative sheet 20 is formed into an L-shape in a side view, a rectangular shape in a top view, and has a 4R corner portion.

[0070] (Example 2)

[0071] In Example 2, a surface protection layer 4 made of acrylic urethane resin was provided on the other surface of the PMMA film (ie, the outermost layer of the decorative sheet 20). The decorative sheet 20 and the molded article were produced under the same conditions as in Example 1 except for the above.

[0072] (Example 3)

[0073] In Example 3, a PP (polypropylene) film was used as the thermoplastic resin layer 3. In addition, a pattern layer 2 was provided on the other surface of the thermoplastic resin layer 3 (i.e., the surface opposite to the surface on which the pattern layer 2 was provided in Example 1). In addition, PP was extruded on the surface of the pattern layer 2 to provide a transparent layer. In addition, a surface protective layer 4 made of an acrylic urethane resin was provided on the outermost layer of the decorative sheet 20. In addition, the thickness of the ABS substrate (substrate layer 1) was set to 300 μm. Except for this, the decorative sheet 20 and the molded product were produced under the same conditions as in Example 1.

[0074] (Example 4)

[0075] In Example 4, the thickness of the PMMA film (thermoplastic resin layer 3) was set to 75 μm. In addition, the thickness of the ABS substrate (substrate layer 1) was set to 430 μm. A decorative sheet 20 and a molded product were produced under the same conditions as in Example 1 except for the above.

[0076] (Example 5)

[0077] In Example 5, the thickness of the PMMA film (thermoplastic resin layer 3) was set to 50 μm. In addition, the thickness of the ABS substrate (substrate layer 1) was set to 430 μm. A decorative sheet 20 and a molded product were produced under the same conditions as in Example 1 except for the above.

[0078] (Example 6)

[0079] In Example 6, a coextruded multilayer film composed of a PVDF layer and a PMMA layer (manufactured by Mitsubishi Chemical Co., Ltd.) was used as the thermoplastic resin layer 3 having the surface protection layer 4. The thickness of the PMMA film was set to 50 μm. In addition, the thickness of the ABS substrate (substrate layer 1) was set to 430 μm. Except for this, the decorative sheet 20 and the molded product were produced under the same conditions as in Example 1.

[0080] (Comparative Example 1)

[0081] In Comparative Example 1, a PP film is used as the thermoplastic resin layer 3. The thickness of the PP film is set to 160 μm. In addition, a pattern layer 2 is provided on the other surface of the thermoplastic resin layer 3 (i.e., the surface opposite to the surface on which the pattern layer 2 is provided in Example 1). In addition, PP is extruded on the surface of the pattern layer 2 to provide a transparent layer. In addition, a surface protection layer 4 made of an acrylic urethane resin is provided on the outermost layer of the decorative sheet 20. In addition, a PETG (high-strength polyethylene terephthalate) film is used as the substrate layer 1. The thickness of the PETG film is set to 250 μm. Except for the above, the decorative sheet 20 and the molded product were produced under the same conditions as in Example 1.

[0082] (Performance Evaluation)

[0083] The following performance evaluations were performed on the decorative sheets 20 of Examples 1 to 6 and Comparative Example 1.

[0084] (Determination of tensile modulus (storage elastic coefficient))

[0085] First, a test piece with a width of 8 mm and a length of 15 mm was prepared from the decorative sheet 20. Next, the prepared test piece was mounted using a DMA machine ("Dynamic Viscoelasticity Tester" manufactured by Perkin Elmer) so that the initial inter-chuck distance was 10.77 mm. Then, when the ambient temperature was changed under the conditions of a starting temperature of 30°C, an end temperature of 150°C, and a heating rate of 5°C / min, and the storage modulus of the mounted test piece was measured at a measurement frequency of 1.0 Hz, as shown in FIG. Figure 2 As shown, the ratio R (=(G2-G3) / (G1-G2)) of the difference (G2-G3) between the second storage modulus G2 when the decorative sheet 20 changes from the glassy region to the transition region and the third storage modulus G3 when the decorative sheet 20 changes from the transition region to the rubbery flat region relative to the difference (G1-G2) between the first storage modulus G1 and the second storage modulus G2 when the ambient temperature is 30°C is calculated. In addition, at the same time, the temperature range (=T3-T2) of the difference between the ambient temperature T3 when the storage modulus of the decorative sheet 20 becomes the third storage modulus G3 and the ambient temperature T2 when the storage modulus of the decorative sheet 20 becomes the second storage modulus G2 is calculated.

[0086] (Thickness difference test after the first molding)

[0087] In the first post-molding thickness difference test, the moldability of the molded product when the temperature of the decorative sheet 20 changes during molding was tested. Specifically, for each molded product with different molding temperatures (100°C, 110°C, 120°C), the thickness of the corner portion of 4R of the decorative sheet 20 was measured, and the difference between the maximum and minimum values ​​of the measured thicknesses was calculated. Then, the case where the difference is 20μm or less is set as "◎", the case where the difference is greater than 20μm and less than 60μm is set as "○", the case where the difference is greater than 60μm and less than 120μm is set as "△", and the case where the difference is greater than 120μm is set as "×". The reason for setting 120μm as the threshold between "◎", "○", "△" and "×" is that, although it depends on the total film thickness of the decorative sheet 20, when a thickness change of more than 120μm occurs, poor appearance and reduction of physical properties (such as scratch resistance) caused by the thinning of the decorative sheet 20 will occur.

[0088] (Thickness difference test after the second molding)

[0089] In the second post-molding thickness difference test, the moldability of the molded product was tested to confirm the thickness deviation generated in one molded product when the decorative sheet 20 was molded at a certain temperature. Figure 3The thickness at the position indicated by the circle in the figure, that is, the thickness of the upper surface of the molded product obtained by molding the decorative sheet 20 at a molding temperature of 100°C, the thickness of the corner portion of 4R, and the thickness of two points in parallel in the vertical direction on the side surface, calculate the difference between the maximum value and the minimum value of the thickness of the four points measured. Then, the case where the difference is less than 100μm is set as "◎", the case where the difference is greater than 100μm and less than 110μm is set as "○", the case where the difference is greater than 110μm and less than 120μm is set as "△", and the case where the difference is greater than 120μm is set as "×".

[0090] (Evaluation results)

[0091] These evaluation results are shown in Table 1 below.

[0092] [Table 1]

[0093]

[0094] As shown in Table 1, in the decorative sheets 20 of Examples 1 to 6, the ratio R (= (G2-G3) / (G1-G2)) is less than 3.5. In addition, the first post-molding thickness difference test and the second post-molding thickness difference test are qualified "◎", "○" or "△", and the comprehensive evaluation based on these test results is qualified "◎", "○" or "△". On the other hand, in the decorative sheet 20 of Comparative Example 1, the ratio R is greater than 3.5. In addition, the first post-molding thickness difference test and the second post-molding thickness difference test are unqualified "×", and the comprehensive evaluation based on these test results is unqualified "×".

[0095] This confirmed that the decorative sheets 20 of Examples 1 to 6 have a wider temperature range (molding temperature range) allowed during molding than the decorative sheet 20 of Comparative Example 1 and are excellent in moldability.

[0096] <2. Second Embodiment: Decorative Sheet>

[0097] Next, a decorative sheet according to a second embodiment of the present invention will be described.

[0098] [2-1.Topic]

[0099] In the past, a decorative sheet having, for example, an ABS substrate layer and a thermoplastic resin layer provided on the surface side of the ABS substrate layer has been proposed (see, for example, Japanese Patent No. 5055707). In the decorative sheet described in Japanese Patent No. 5055707, the decorative sheet is inserted into a mold cavity, a resin in a flowing state is filled into the mold cavity, the resin is solidified, and the solidified resin and the decorative sheet are integrated to produce a molded product. However, the present inventors have found that, in the decorative sheet described in Japanese Patent No. 5055707, when the sheet temperature during molding changes, the sheet thickness of the decorative sheet in the molded product changes.

[0100] An object of the decorative sheet according to the second embodiment is to provide a decorative sheet capable of stabilizing the sheet thickness in a molded product even if the sheet temperature changes during molding.

[0101] [2.2 Composition]

[0102] The overall structure of the decorative sheet 20 of the second embodiment is similar to Figure 1 The same. That is, Figure 1 As shown, the decorative sheet 20 according to the second embodiment is configured to include a substrate layer 1 and a thermoplastic resin layer 3 provided on the surface 1a side of the substrate layer 1. The total thickness of the decorative sheet 20 according to the second embodiment is preferably 255 μm to 550 μm, and more preferably 275 μm to 550 μm. In addition, from the viewpoint of moldability and surface strength of the decorative sheet 20, the ratio of the thickness of the thermoplastic resin layer 3 to the substrate layer 1 is preferably 1:1.5 to 1:7, and more preferably 1:2.5 to 1:6. In particular, from the viewpoint of stability of the sheet thickness of the flat part / corner part and abnormal appearance, it is more preferable to satisfy: the total thickness of the decorative sheet 20 is 275 μm to 550 μm, and the ratio of the thickness of the thermoplastic resin layer 3 to the substrate layer 1 is 1:2.5 to 1:6. In addition, as a lamination method of each layer such as the substrate layer 1, the pattern layer 2 and the thermoplastic resin layer 3, the same method as the lamination method of each layer of the decorative sheet 20 of the first embodiment can be used.

[0103] In addition, among the layers of the second embodiment, the following layers are used for the base material 1 and the thermoplastic resin layer 3 , and the same layers as those of the first embodiment are used for the other layers.

[0104] (Base material layer)

[0105] As the material of the substrate layer 1 of the second embodiment, ABS resin can be used (for example). As the ABS resin, for example, a polymer blend of styrene-chloronitrile copolymer and NBR can be used; a graft type obtained by graft copolymerizing styrene and acrylonitrile in the coexistence of BR or SBR latex. From the viewpoint of easy elongation, the content ratio of butadiene is preferably not less than 20% by weight and not more than 50% by weight. In addition, the substrate 1 of the second embodiment can be a single layer or a multilayer. In addition, similar to the substrate layer 1 of the first embodiment, the thickness of the substrate layer 1 of the second embodiment is preferably not less than 196μm and not more than 413μm.

[0106] (Thermoplastic resin layer)

[0107] As a material of the thermoplastic resin layer 3 of the second embodiment, for example, at least one selected from polymethyl methacrylate resin, polypropylene resin and polyvinyl chloride resin can be used. In addition, the thermoplastic resin layer 3 of the second embodiment may be a single layer or a multilayer. In addition, similarly to the thermoplastic resin layer 3 of the first embodiment, the thickness of the thermoplastic resin layer 3 of the second embodiment is preferably 50 μm or more and 144 μm or less.

[0108] As described above, the decorative sheet 20 according to the second embodiment includes the substrate layer 1 and the thermoplastic resin layer 3 provided on the surface 1a side of the substrate layer 1. In addition, the substrate layer 1 contains ABS resin. In addition, the total thickness of the decorative sheet 20 is 255 μm or more and 550 μm or less, and the ratio of the thickness of the thermoplastic resin layer 3 to the substrate layer 1 is 1:1.5 to 1:7. Therefore, since the thickness of the substrate layer 1 and the thermoplastic resin layer 3 and the ratio thereof are appropriate, even if the sheet temperature during molding changes, the decorative sheet 20 having a stable sheet thickness in the molded product can be provided.

[0109] In addition, for example, even if temperature changes occur in various parts of the decorative sheet 20, excessively stretched portions can be prevented from occurring, and uneven thickness of the decorative sheet 20 can be prevented. Therefore, a decorative sheet 20 having a wide moldable temperature range can be provided.

[0110] In addition, even if the molding machine or molding conditions are changed, the moldability can be stabilized.

[0111] Furthermore, by using the decorative sheet 20 whose thickness is less likely to be uneven, it is possible to prevent the strength of the molded product from varying depending on the position, and also to prevent the design from varying.

[0112] Incidentally, when the total thickness of the decorative sheet 20 is less than 255 μm, the surface strength of the decorative sheet 20 becomes weak. In addition, when the total thickness of the decorative sheet 20 is greater than 550 μm, the handleability of the decorative sheet 20 becomes poor. Further, when the ratio of the thickness of the base material layer 1 to the thickness of the thermoplastic resin layer 3 is less than 1.5, the moldability becomes poor. In addition, when the ratio of the thickness of the base material layer 1 to the thickness of the thermoplastic resin layer 3 is greater than 7, the surface strength of the decorative sheet 20 becomes weak.

[0113] [2-3. Example]

[0114] Hereinafter, examples and comparative examples of the decorative sheet 20 according to the second embodiment will be described. It should be noted that the present invention is not limited to the following examples.

[0115] (Example 1)

[0116] First, an acrylic film original sheet and an ABS substrate are prepared as the thermoplastic resin layer 3 and the substrate layer 1. The thickness of the acrylic film original sheet is set to 125 μm. In addition, the thickness of the ABS substrate is set to 380 μm. Then, the acrylic film original sheet and the ABS substrate are heat-laminated to produce a decorative sheet 20 with a total thickness of 505 μm. Next, the decorative sheet 20 is heated to a set temperature under a vacuum environment using a TOM molding machine ("NGF-0406-T" manufactured by "Fuse Vacuum Co., Ltd."), and then a single side of the decorative sheet 20 is pressurized and vacuum molded. The set temperature (molding temperature) is set to three types: 100°C, 110°C, and 120°C. In the pressurized vacuum molding, as Figure 3 As shown, it is formed into an L-shape in a side view and a rectangular shape in a top view, and has a 1R corner portion and a 4R corner portion.

[0117] In this way, the surface portion of a molded product used in the IML molding method was produced.

[0118] (Example 2)

[0119] In Example 2, the thickness of the thermoplastic resin layer 3 was 75 μm, the thickness of the base layer 1 was 200 μm, and the total thickness of the decorative sheet 20 was 275 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0120] (Example 3)

[0121] In Example 3, a polypropylene original sheet was used as the thermoplastic resin layer 3. In addition, the thickness of the thermoplastic resin layer 3 was set to 90 μm, the thickness of the base layer 1 was set to 380 μm, and the total thickness of the decorative sheet 20 was set to 470 μm. Except for the above, the decorative sheet 20 and the surface portion of the molded product were produced under the same conditions as in Example 1.

[0122] (Example 4)

[0123] In Example 4, a laminated body obtained by laminating an acrylic film original sheet having a thickness of 75 μm and a polyvinyl chloride resin having a thickness of 40 μm was used as the thermoplastic resin layer 3. In addition, the thickness of the base material layer 1 was set to 380 μm, and the total thickness of the decorative sheet 20 was set to 495 μm. Except for the above, the decorative sheet 20 and the surface portion of the molded product were produced under the same conditions as in Example 1.

[0124] (Example 5)

[0125] In Example 5, the thickness of the thermoplastic resin layer 3 was 125 μm, the thickness of the base layer 1 was 200 μm, and the total thickness of the decorative sheet 20 was 325 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0126] (Example 6)

[0127] In Example 6, the thickness of the thermoplastic resin layer 3 was 75 μm, the thickness of the base layer 1 was 430 μm, and the total thickness of the decorative sheet 20 was 505 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0128] (Example 7)

[0129] In Example 7, the thickness of the thermoplastic resin layer 3 was 75 μm, the thickness of the base layer 1 was 180 μm, and the total thickness of the decorative sheet 20 was 255 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0130] (Comparative Example 1)

[0131] In Comparative Example 1, a polypropylene original sheet was used as the thermoplastic resin layer 3. In addition, a PETG substrate was used as the substrate layer 1. In addition, the thickness of the thermoplastic resin layer 3 was set to 160 μm, the thickness of the substrate layer 1 was set to 350 μm, and the total thickness of the decorative sheet 20 was set to 510 μm. Except for the above, the decorative sheet 20 and the surface portion of the molded product were produced under the same conditions as in Example 1.

[0132] (Comparative Example 2)

[0133] In Comparative Example 2, a PETG substrate was used as the substrate layer 1. In addition, the thickness of the thermoplastic resin layer 3 was set to 125 μm, the thickness of the substrate layer 1 was set to 120 μm, and the total thickness of the decorative sheet 20 was set to 245 μm. Except for the above, the decorative sheet 20 and the surface portion of the molded product were produced under the same conditions as in Example 1.

[0134] (Comparative Example 3)

[0135] In Comparative Example 3, the thickness of the thermoplastic resin layer 3 was 50 μm, the thickness of the base layer 1 was 180 μm, and the total thickness of the decorative sheet 20 was 230 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0136] (Comparative Example 4)

[0137] In Comparative Example 4, the thickness of the thermoplastic resin layer 3 was 125 μm, the thickness of the base layer 1 was 400 μm, and the total thickness of the decorative sheet 20 was 525 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0138] (Comparative Example 5)

[0139] In Comparative Example 5, the thickness of the thermoplastic resin layer 3 was 125 μm, the thickness of the base layer 1 was 180 μm, and the total thickness of the decorative sheet 20 was 305 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0140] (Comparative Example 6)

[0141] In Comparative Example 6, the thickness of the thermoplastic resin layer 3 was 50 μm, the thickness of the base layer 1 was 380 μm, and the total thickness of the decorative sheet 20 was 430 μm. The decorative sheet 20 and the surface portion of the molded article were prepared under the same conditions as in Example 1 except for the above.

[0142] (Performance Evaluation)

[0143] The following performance evaluations were performed on the decorative sheets 20 of Examples 1 to 7 and Comparative Examples 1 to 6.

[0144] (First thickness test)

[0145] In the first thickness test, it was tested whether the thickness of the sheet in the molded product is stable even if the temperature of the decorative sheet 20 changes during molding. Specifically, the difference between the thickness of the decorative sheet 20 formed at a set temperature (molding temperature) of 100°C and the thickness of the decorative sheet 20 formed at a molding temperature of 110°C was calculated. In addition, the difference between the thickness of the decorative sheet 20 formed at a molding temperature of 120°C and the thickness of the decorative sheet 20 formed at a molding temperature of 110°C was calculated. Then, the case where the above difference is within the range of ±15% is set to "○" for passing, and the case where the above difference is outside the range of ±15% is set to "×" for failing.

[0146] It should be noted that in the thickness measurement of the decorative sheet 20, a digital micrometer (manufactured by "Mitsutoyo") was used for the upper surface (flat portion) of the molded product, and a point digital micrometer ("MCD232-25P" manufactured by "Niigata Seiki") was used for the corner portion (curved portion) of the molded product. Then, according to the thickness measurement method of JIS K 7130A, the thickness of the decorative sheet 20 molded at 110°C, that is, the upper surface (the part of the sheet least stretched) of the molded product was set as 100%, and the thickness from the upper surface of the molded product to the corner portion of the side was measured, and this value was set as the center value, and the thickness of the decorative sheet 20 (molded product) molded at ±10°C (100°C, 120°C) was measured.

[0147] (Appearance test)

[0148] In the appearance test, it is tested whether the appearance of the molded product is abnormal even if the temperature of the decorative sheet 20 changes during molding. Then, if there is no abnormality such as foaming, cracking, whitening, etc. in the appearance, it is rated as "pass", and if there is abnormality such as foaming, cracking, whitening, etc. in the appearance, it is rated as "failure".

[0149] (Second thickness test)

[0150] In the second thickness test, for each molded product with different molding temperatures (100°C, 110°C, 120°C), the difference between the thickness of the corner portion of 1R and the thickness of the corner portion of 4R was calculated. Then, if the difference was within the range of ±50μm, it was rated as "○", and if it was outside the range of ±50μm, it was rated as "×".

[0151] (Coin scratch test)

[0152] In the coin scratch test, a coin with a load of 2 kg was applied to scratch the decorative sheet 20 on the upper surface (flat portion) of the molded product. Then, the case where there was no scratch on the decorative sheet 20 was rated as "good", the case where a thin linear scratch was formed on the decorative sheet 20 was rated as "good", the case where a scratch deeper than the linear scratch but still shallower was formed on the decorative sheet 20 was rated as "unqualified" ", and the case where a deep scratch was formed on the decorative sheet 20 was rated as "unqualified" ".

[0153] (Evaluation results)

[0154] These evaluation results are shown in Table 2 below.

[0155] [Table 2]

[0156]

[0157] As shown in Table 2, in the decorative sheets 20 of Examples 1 to 7, the comprehensive evaluation based on the test results of the first thickness test, the appearance test, the second thickness test, and the coin scratch test was qualified "○". On the other hand, in the decorative sheets 20 of Comparative Examples 1 to 6, the comprehensive evaluation based on the test results of the first thickness test, the appearance test, the second thickness test, and the coin scratch test was unqualified "×".

[0158] Therefore, it can be confirmed that the decorative sheets 20 of Examples 1 to 7 have a stable sheet thickness in the molded product even when the sheet temperature changes during molding, compared with the decorative sheets 20 of Comparative Examples 1 to 6. In addition, it can be confirmed that even when the temperature changes at various parts of the decorative sheet 20, the occurrence of excessively stretched portions can be prevented, and the thickness of the decorative sheet 20 can be prevented from being uneven.

[0159] Furthermore, it was confirmed that the decorative sheets 20 of Examples 1 to 4, i.e., the decorative sheets 20 having a total thickness of 275 μm or more and 550 μm or less and a thickness ratio of the thermoplastic resin layer 3 to the base material layer 1 of 1:2.5 to 1:6, all passed the first thickness test, the appearance test, the second thickness test, and the coin scratch test with "◎" or "○". In addition, it was confirmed that the decorative sheets 20 of Examples 1 to 7 had higher surface strength and better scratch resistance than the decorative sheets 20 of Comparative Examples 3 and 6.

[0160] <3. Third Embodiment: Decorative Sheet for Automobile Interior>

[0161] Next, a decorative sheet for automobile interior according to a third embodiment of the present invention will be described.

[0162] [3-1.Topic]

[0163] In the past, a decorative sheet for automobile interiors having a substrate, a heat seal layer, a pattern layer and a transparent film layer laminated in sequence has been proposed (see, for example, Japanese Patent Publication No. 2015-054558). In the decorative sheet for automobile interiors described in Japanese Patent Publication No. 2015-054558, a heat lamination process is performed by heating and merging a laminate composed of a heat seal layer, a pattern layer and a transparent film layer with a substrate. However, the inventors have found that, in the decorative sheet for automobile interiors described in Japanese Patent Publication No. 2015-054558, for example, when a heat lamination process is performed at a low temperature, due to the unevenness of the dots of the ink of the pattern layer, gas stagnation occurs at the interface between the pattern layer and the substrate, and poor appearance occurs due to the gas stagnation.

[0164] An object of the automobile interior decorative sheet according to the third embodiment is to provide an automobile interior decorative sheet capable of suppressing the above-mentioned poor appearance caused by gas stagnation.

[0165] [3-2. Structure]

[0166] like Figure 4 As shown in FIG. 1 , the overall structure of the automotive interior decorative sheet 30 according to the third embodiment is a structure including a heat seal layer 9 replacing the adhesive layer 5 of the second embodiment and a transparent film layer 10 replacing the thermoplastic resin layer 3 of the second embodiment. That is, the structure includes a substrate layer 1, a heat seal layer 9 provided on the surface 1a side of the substrate layer 1, a pattern layer 2 provided on the surface 9a side of the heat seal layer 9, a transparent film layer 10 provided on the surface 2a side of the pattern layer 2, and a surface protection layer 4 provided on the surface 10a side of the transparent film layer 10.

[0167] In addition, regarding the total thickness of the automotive interior decorative sheet 30 of the third embodiment, the ratio of the thickness of the thermoplastic resin layer 3 to the base material layer 1, and the lamination method of each layer, it can use the same total thickness, ratio, and lamination method as the decorative sheet 20 according to the first embodiment. Furthermore, among the layers of the third embodiment, the heat seal layer 9, the pattern layer 2, the transparent film layer 10, and the surface protection layer 4 use the layers described below, and the other layers use the same layers as the layers of the first embodiment.

[0168] (Heat seal layer)

[0169] The heat seal layer 9 is a layer for combining the laminate 11 composed of the heat seal layer 9, the pattern layer 2 and the transparent film layer 10 with the base layer 1 by heat lamination. As the material of the heat seal layer 9, for example, a heat sealant can be used. As the heat sealant, for example, a resin obtained by mixing an acrylic resin and a vinyl chloride acetate resin in a mass ratio of 60:40 to 70:30 can be used. By containing 60% to 70% of the acrylic resin, the adhesion to the pattern layer 2 can be improved when the pattern layer 2 is composed of acrylic ink. In addition, by containing 30% to 40% of the vinyl chloride acetate resin, the adhesion to the base layer 1 can be improved when the base layer 1 is composed of ABS resin. As the acrylic resin, for example, "Acryl LS#3002" manufactured by "Toei Chemicals" can be used. Moreover, as a vinyl chloride acetate type resin, "V424 PVC polymer" manufactured by "Toyo Ink Co., Ltd." can be used, for example.

[0170] In addition, the weight per unit area of ​​the heat seal layer 9 is 30% or more and less than 150% relative to the weight per unit area of ​​the pattern layer 2. When it is less than 30%, gas stagnation occurs at the interface between the laminate 11 and the substrate layer 1, and the appearance of the automotive interior decorative sheet 30 is poor. In addition, when it is greater than 150%, the solvent foams in the heat seal layer 9, and the appearance of the automotive interior decorative sheet 30 is poor. In particular, from the viewpoint of the adhesion between the laminate 11 and the substrate layer 1, the weight per unit area of ​​the heat seal layer 9 is most preferably 30% or more and less than 100% relative to the weight per unit area of ​​the pattern layer 2. When it is greater than 100%, although the appearance of the automotive interior decorative sheet 30 does not deteriorate, the solvent foams in the heat seal layer 9, and the adhesion between the laminate 11 and the substrate layer 1 is reduced.

[0171] (Pattern layer)

[0172] The pattern layer 2 is a layer for imparting design characteristics due to the pattern to the automotive interior decorative sheet 30. The pattern layer 2 is formed by using a printing ink obtained by dissolving or dispersing a colorant such as a dye or a pigment together with an appropriate binder resin in an appropriate diluent solvent. The printing ink is applied by various printing methods such as gravure printing and offset printing. In addition, as the binder resin, for example, urethane resins, acrylic resins, vinyl acetate resins, polyimide resins, nitrocellulose, etc., or mixtures thereof, etc. can be used.

[0173] In particular, when the transparent film layer 10 is an acrylic film, it is preferred to use acrylic ink using an acrylic resin as a binder. In addition, the pattern may be, for example, a wood grain pattern, a stone grain pattern, a cloth grain pattern, an abstract pattern, a geometric pattern, a character, a symbol, a solid color, or a combination thereof. In addition, in order to improve the concealment of the automotive interior decorative sheet 30, a concealing layer made of an opaque printing ink or coating containing a large amount of opaque pigments such as titanium dioxide or iron oxide may be provided between the pattern layer 2 and the heat sealing layer 9.

[0174] (Transparent film layer)

[0175] The transparent film layer 10 is a layer for covering and protecting the surface 3a of the pattern layer 2. In addition, the transparent film layer 10 is a film-like layer that becomes the base of the laminate 11 when manufacturing the automotive interior decorative sheet 30. As the material of the transparent film layer 10, for example, a thermoplastic resin can be used. As the thermoplastic resin, for example, polycarbonate, polymethyl methacrylate, polypropylene, etc., or a mixture, copolymer, composite, laminate, etc. thereof can be used.

[0176] It should be noted that the transparency of the transparent film layer 10 is preferably such that the pattern of the pattern layer 2 can be seen through. For example, the transparent film layer 10 may be colorless and transparent, colored and transparent, or semi-transparent.

[0177] (Surface protection layer)

[0178] The surface protection layer 4 is a layer provided as needed to protect the surface of the decorative sheet 30 for automobile interior. As the material of the surface protection layer 4, for example, acrylic resin, fluororesin, silicone resin can be used. As acrylic resin, for example, poly(meth)acrylonitrile, poly(methyl)acrylate, poly(ethyl)acrylate, poly(butyl)acrylate, polyacrylamide, etc. can be used. In addition, as fluororesin, for example, polyvinylidene fluoride, tetrafluoroethylene resin, tetrafluoroethylene perfluoroalkoxy vinyl ether copolymer, tetrafluoroethylene / hexafluoropropylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene / ethylene copolymer, chlorotrifluoroethylene-ethylene copolymer, polyvinyl fluoride (PVF) can be used.

[0179] [3-3. Method for producing decorative sheet for automobile interior]

[0180] Next, a method for producing the automotive interior decorative sheet 30 according to the third embodiment will be described.

[0181] First, a printing ink is applied on one surface of the transparent film layer 10 to form a pattern layer 2. The pattern of the pattern layer 2 is printed by back printing. Then, a heat sealant is applied on the back side 2b of the pattern layer 2, and the applied heat sealant is dried to form a heat seal layer 9. At this time, the unit area weight of the heat seal layer 9 is 30% or more and less than 150% relative to the unit area weight of the pattern layer 2. In particular, by adjusting the unit area weight of the heat seal layer 9 to 30%, the solvent contained in the heat seal layer 9 is reduced to the necessary minimum amount, and the volatile organic matter discharged from the heat seal layer 9 is reduced, which is preferred. Thus, a laminate 11 in which the heat seal layer 9, the pattern layer 2 and the transparent film layer 10 are sequentially laminated is formed.

[0182] Next, the base material layer 1 and the back surface 11b (ie, the surface on the heat sealant layer 9 side) of the laminate 11 are joined together by heat lamination. Thus, the decorative sheet 30 for automobile interior is manufactured.

[0183] As described above, in the automotive interior decorative sheet 30 according to the third embodiment, the weight per unit area of ​​the heat sealant layer 9 is set to 30% or more and less than 150% relative to the weight per unit area of ​​the pattern layer 2. Therefore, the adhesion between the pattern layer 2 and the base layer 1 can be improved, and when the thermal lamination process is performed at a low temperature, the occurrence of gas stagnation where air is stagnant at the interface between the pattern layer 2 and the base layer 1 can be suppressed. Therefore, the automotive interior decorative sheet 30 can be provided, which can suppress the poor appearance caused by gas stagnation. In addition, since gas stagnation can be suppressed, the thermal lamination process at a low temperature can be performed.

[0184] In addition, in recent years, due to the revision of the Air Pollution Control Act, emission restrictions on volatile organic compounds (VOC) have been implemented, and it is necessary to reduce the emitted volatile organic compounds. In contrast, in the automotive interior decorative sheet 30 according to the third embodiment, the coating containing a large amount of volatile organic compounds such as acrylic ink is sheeted, so that the solvent content can be reduced. In addition, by sheeting, the reproducibility of the design and rich patterns can be achieved.

[0185] In particular, in the automotive interior decorative sheet 30 according to the third embodiment, the weight per unit area of ​​the heat sealant layer 9 is preferably 30% or more and less than 100% relative to the weight per unit area of ​​the pattern layer 2. By setting the weight per unit area to be such, the adhesion between the pattern layer 2 and the base layer 1 can be further improved, and the gas stagnation at the interface between the pattern layer 2 and the base layer 1 can be more reliably suppressed.

[0186] In addition, in the automotive interior decorative sheet 30 according to the third embodiment, when the base material layer 1 contains ABS resin and the pattern layer 2 contains acrylic ink, it is preferable that the heat sealant constituting the heat seal layer 9 is a resin obtained by mixing an acrylic resin and a vinyl chloride acetate resin at a mass ratio of 60:40 to 70:30. In this way, both the adhesion between the base material layer 1 and the heat seal layer 9 and the adhesion between the pattern layer 2 and the heat seal layer 9 can be improved.

[0187] [3-4. Example]

[0188] Hereinafter, examples and comparative examples of the automotive interior decorative sheet 30 according to the third embodiment will be described. It should be noted that the present invention is not limited to the following examples.

[0189] (Example 1)

[0190] First, if Figure 4 As shown in FIG. 1 , a transparent film layer 10 is prepared. As the transparent film layer 10, a film original sheet of polymethyl methacrylate (acrylic film original sheet) is used. Next, a pattern layer 2 made of acrylic ink is formed on one surface of the transparent film layer 10 by gravure printing. The coating amount of the acrylic ink is set to 3 g / m 2 in a dry state. 2 .

[0191] Subsequently, a heat sealant was applied to the back side 2b of the pattern layer 2 using a bar coater. As the heat sealant, a resin obtained by mixing acrolein (LS#3002) and PVC primer (acrylic, vinyl chloride acetate, V424) at a mass ratio of 68:32 was used. The applied heat sealant was dried for 30 seconds at room temperature of 40°C to form a heat sealant layer 9. In the dry state, the coating amount of the sealant was set to 1 g / m 2 That is, the weight per unit area of ​​the heat sealant layer 9 was adjusted to 33% of the weight per unit area of ​​the pattern layer 2 .

[0192] Thus, a laminate 11 having the heat seal layer 9, the pattern layer 2 and the transparent film layer 10 laminated in this order was formed. Next, the base material layer 1 was attached to the back surface 11b of the laminate 11 by heat lamination using a 140°C bag processing machine. The processing speed was set to 2 m / min.

[0193] In this way, the automotive interior decorative sheet 30 of Example 1 was manufactured.

[0194] (Example 2)

[0195] In Example 2, the coating amount of the heat sealant of the heat seal layer 9 was set to 3 g / m 2That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to 100% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0196] (Example 3)

[0197] In Example 3, the coating amount of the heat sealant of the heat seal layer 9 was set to 2.8 g / m 2 That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to 98% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0198] (Example 4)

[0199] In Example 4, the coating amount of the heat sealant of the heat seal layer 9 was set to 4.4 g / m 2 That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to be 148% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0200] (Example 5)

[0201] In Example 5, a resin obtained by mixing acrolein and PVC primer at a mass ratio of 58:42 was used as the heat sealant of the heat seal layer 9. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0202] (Example 6)

[0203] In Example 6, a resin obtained by mixing acrolein and PVC primer at a mass ratio of 72:28 was used as the heat sealant of the heat seal layer 9. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0204] (Comparative Example 1)

[0205] In Comparative Example 1, the heat seal layer 9 was omitted. That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to 0% relative to the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was prepared under the same conditions as in Example 1 except for the above.

[0206] (Comparative Example 2)

[0207] In Comparative Example 2, the heat seal coating amount of the heat seal layer 9 was set to 6 g / m 2That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to 200% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0208] (Comparative Example 3)

[0209] In Comparative Example 3, the heat seal coating amount of the heat seal layer 9 was set to 10 g / m 2 That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to be 333% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0210] (Comparative Example 4)

[0211] In Comparative Example 4, the heat seal coating amount of the heat seal layer 9 was set to 0.8 g / m 2 That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to be 28% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0212] (Comparative Example 5)

[0213] In Comparative Example 5, the heat seal coating amount of the heat seal layer 9 was set to 4.6 g / m 2 That is, the weight per unit area of ​​the heat seal layer 9 was adjusted to be 152% of the weight per unit area of ​​the pattern layer 2. A decorative sheet 30 for automobile interior was produced under the same conditions as in Example 1 except for the above.

[0214] (Performance Evaluation)

[0215] The following performance evaluations were performed on the automotive interior decorative sheets 30 of Examples 1 to 6 and Comparative Examples 1 to 5.

[0216] (Evaluation of Solvent Amount)

[0217] In the evaluation of the solvent amount, a gas chromatograph ("GC-2010" manufactured by "Shimadzu Corporation") was used to analyze the solvent amount from 0.1 m 2 The amount of solvent volatilized from the automotive interior decorative sheet 30. Regarding the evaluation criteria, the case where the amount of solvent is less than 1.6 mg is rated as "◎", the case where the amount of solvent is 1.6 mg or more and less than 3.0 mg is rated as "○", and the case where the amount of solvent is 3.0 mg or more is rated as "×".

[0218] (Appearance evaluation)

[0219] In the appearance evaluation, a laser microscope ("J5664" manufactured by "Orionpass") was used to observe the interface between the laminate 11 and the base layer 1 and the heat seal layer 9. Regarding the evaluation criteria, the case where there was no gas entrapment at the interface and no solvent foaming in the heat seal layer 9 was rated as "good", and the case where there was gas entrapment or solvent foaming was rated as "bad".

[0220] (Lamination Strength Evaluation)

[0221] In the evaluation of lamination strength, the laminate 11 of the automotive interior decorative sheet 30 was stretched by hand to evaluate whether it peeled, that is, whether interface peeling or cohesive peeling occurred. Regarding the evaluation criteria, the case where there was no interface peeling or cohesive peeling was rated as "good", the case where there was no interface peeling or cohesive peeling but there was a sign of it was rated as "good", and the case where there was interface peeling or cohesive peeling was rated as "bad".

[0222] (Evaluation results)

[0223] These evaluation results are shown in Table 3 below.

[0224] [Table 3]

[0225]

[0226] As shown in Table 3, in the automotive interior decorative sheets 30 of Examples 1 to 6, since the weight per unit area of ​​the heat sealant is small, the evaluation result of the solvent amount evaluation is qualified "◎" or "○". In particular, the evaluation results in Examples 1, 3 and 6 are "◎". In addition, in the automotive interior decorative sheets 30 of Examples 1 to 3, the evaluation results of the appearance evaluation and the lamination strength evaluation are each qualified "○". In addition, in the automotive interior decorative sheets 30 of Examples 5 and 6, the appearance evaluation is qualified "○", but the lamination strength evaluation is qualified "△". Therefore, the comprehensive evaluation based on the solvent amount evaluation, appearance evaluation and lamination strength evaluation is qualified "◎", "○" or "△".

[0227] On the other hand, in the decorative sheet 30 for automobile interior of Comparative Example 1, since it does not have a heat seal layer 9, gas stagnation occurs at the interface between the pattern layer 2 and the substrate layer 1, and the appearance is evaluated as unqualified "×". In addition, the bonding strength between the pattern layer 2 and the substrate layer 1 is low, and the lamination strength is evaluated as unqualified "×". In addition, in the decorative sheets 30 for automobile interior of Comparative Examples 2, 3, and 5, since the unit area weight of the heat sealant is large, the evaluation result of the solvent amount is a large value. In addition, since the amount of solvent is large, the solvent foams in the heat seal layer 9, and the appearance is evaluated as unqualified "×". In addition, in the decorative sheet 30 for automobile interior of Comparative Example 4, gas stagnation occurs at the interface between the laminate 11 and the substrate layer 1, and the appearance is evaluated as unqualified "×". Therefore, in Comparative Examples 1 to 5, the comprehensive evaluation based on the solvent amount evaluation, appearance evaluation, and lamination strength evaluation is unqualified "×".

[0228] Therefore, it can be confirmed that the automotive interior decorative sheets 30 of Examples 1 to 6 have excellent solvent amounts, appearances, and peeling resistance compared to the automotive interior decorative sheets 30 of Comparative Examples 1 to 5.

[0229] Explanation of symbols

[0230] 1···Base material layer; 1a···Surface; 2···Pattern layer; 2a···Surface; 3···Thermoplastic resin layer; 3a···Surface; 4···Surface protection layer; 4a···Surface; 5···Adhesive layer; 6···Concave-convex pattern; 7, 8···Intersection; 9···Heat sealing layer; 9a···Surface; 10···Transparent film layer; 10a···Surface; 11···Laminate; 11b···Back; 20···Decorative sheet; 30···Decorative sheet for automotive interior.

Claims

1. A decorative sheet comprising: Base material layer, and The thermoplastic resin layer provided on the surface side of the substrate layer is characterized in that The substrate layer comprises ABS, and the thickness of the substrate layer is 375 μm. The thermoplastic resin layer includes PP, which is a propylene-α-olefin copolymer having a polypropylene crystal part and containing 15 mol % or more of an α-olefin having 2 to 20 carbon atoms other than propylene, The thickness of the thermoplastic resin layer is 125 μm. A test piece with a width of 8 mm is prepared from the decorative sheet. When the ambient temperature is changed under the conditions of a starting temperature of 30°C, an ending temperature of 150°C, and a heating rate of 5°C / min, and the storage modulus of the prepared test piece is measured in a manner such that the initial chuck distance is 10.77 mm and the measurement frequency is 1.0 Hz, the ratio of the difference between the second storage modulus when the decorative sheet changes from the glassy region to the transition region and the third storage modulus when the decorative sheet changes from the transition region to the rubbery flat region to the difference between the first storage modulus and the second storage modulus when the ambient temperature is 30°C is greater than 0.79 times and less than 1.48 times.

2. A decorative sheet comprising: Base material layer, and The thermoplastic resin layer provided on the surface side of the substrate layer is characterized in that The substrate layer comprises ABS resin, wherein the content ratio of butadiene is 20 wt % or more and 50 wt % or less, The substrate layer is the outermost layer of the decorative sheet. The thermoplastic resin layer is in direct contact with the substrate layer, The total thickness of the decorative sheet is 505 μm. The thermoplastic resin layer is an acrylic film, The thermoplastic resin layer is thermally laminated on the substrate layer, The thickness of the substrate layer is 380 μm, the thickness of the thermoplastic resin layer is 125 μm, The difference between the thickness of the decorative sheet formed at a forming temperature of 100°C and that of the decorative sheet formed at a forming temperature of 110°C, and the difference between the thickness of the decorative sheet formed at a forming temperature of 120°C and that of the decorative sheet formed at a forming temperature of 110°C are within the range of ±15%.

3. A decorative sheet comprising: Base material layer, and The thermoplastic resin layer provided on the surface side of the substrate layer is characterized in that The substrate layer comprises ABS resin, wherein the content ratio of butadiene is 20 wt % or more and 50 wt % or less, The substrate layer is the outermost layer of the decorative sheet. The thermoplastic resin layer is in direct contact with the substrate layer, The total thickness of the decorative sheet is 275 μm. The thermoplastic resin layer is an acrylic film, The thermoplastic resin layer is thermally laminated on the substrate layer, The thickness of the substrate layer is 200 μm, the thickness of the thermoplastic resin layer is 75 μm, The difference between the thickness of the decorative sheet formed at a forming temperature of 100°C and that of the decorative sheet formed at a forming temperature of 110°C, and the difference between the thickness of the decorative sheet formed at a forming temperature of 120°C and that of the decorative sheet formed at a forming temperature of 110°C are within the range of ±15%.

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