Synthetic resin skin material, method for producing synthetic resin skin material and molded product

Abstract

To provide a synthetic resin skin material which enables formation of a molding that has good workability when being heated and molded using a die, satisfactorily maintains an uneven form formed on the outermost surface when being layered on an intermediate layer containing various thermoplastic resins, and is excellent in appearance, a method for manufacturing the same, and a molding.SOLUTION: There are provided a synthetic resin skin material which includes a base material layer containing a thermoplastic resin, an intermediate layer that is provided on one surface of the base material layer and contains a thermoplastic resin, and a skin layer that is provided opposite to the base material layer of the intermediate layer, has an uneven pattern on the surface opposite to the intermediate layer side, and contains a polypropylene resin, a method for manufacturing the same, and a molding.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a synthetic resin skin material, a method for producing a synthetic resin skin material, and a molded article. [Background technology]

[0002] In recent years, synthetic resin skin materials, which are highly durable, have been widely used in place of natural leather and fibrous sheets for automobile interior and exterior parts (instrument panels, door trim, seats, ceilings, etc.), railway vehicle and aircraft interior parts (trim, seats, ceilings, etc.), furniture, shoes, footwear, bags, building and exterior components, clothing coverings and linings, wall coverings, etc. Such synthetic resin skin materials have an uneven pattern, i.e., a grain pattern, similar to that of natural leather on their outermost surface, and this grain pattern characterizes their appearance. For example, with regard to automobile interior parts, as vehicles become more luxurious, it has become important to impart a luxurious feel to interior skin materials.

[0003] Methods for producing automotive interior parts using such skin materials include insert molding, i.e., placing a skin material on the surface of a molding resin material and then heat-molding the material in a molding die, and vacuum-molding the heated skin material followed by injection molding, in which a fluid resin is poured into the backside of the skin material. However, with both methods, the textured surface pattern formed by the heat disappears when the heated and softened skin material is molded, and the shape of the molding die is transferred to the surface of the skin material, i.e., the surface that exhibits the exterior appearance, during heat molding. Therefore, the design of the skin layer is generally expressed by printing or mirror finishing. However, forming a molded product with a textured surface requires a mold with a textured pattern corresponding to the design.

[0004] As a resin film whose design does not deteriorate even when heat-molded, a matte acrylic resin film for thermoforming has been proposed, which comprises an acrylic resin film substrate and a matte layer, which is provided as the outermost layer on one side of the acrylic resin film substrate and contains a matting agent, a silicone-containing compound and / or a fluorine-containing compound, and a curable binder resin (see, for example, Patent Document 1). In addition, a synthetic resin skin material has been proposed that includes a base layer containing a thermoplastic resin, an intermediate layer containing a polyvinyl chloride resin, and a skin layer having a textured surface and containing a fluororesin, and that has good processability even when hot-molded, and that maintains the textured pattern formed on the outermost surface, allowing for the formation of a molded product with excellent appearance (see, for example, Patent Document 2).

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-283665 [Patent Document 2] Japanese Patent Application Publication No. 2019-177499 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology described in Patent Document 1, when a molding resin material having a skin material disposed on the surface is heated and molded, the shape of a fine uneven pattern useful for matting is maintained, but when the uneven pattern is complex and deep, the uneven pattern formed on the outermost surface of the skin material may be deformed or lost due to the effects of heating, pressure, etc. The synthetic resin skin material described in Patent Document 2 has a skin layer containing a fluororesin and is excellent in stain resistance, but the problem is that fluororesin is expensive. Furthermore, according to the inventors' studies, when an intermediate layer containing a thermoplastic resin other than polyvinyl chloride is laminated with a skin layer containing a fluororesin, the shape retention effect of the textured pattern of the skin layer may be reduced, and there is still room for improvement from the viewpoint of versatility in selecting the resin to be used in combination.

[0007] An object of one embodiment of the present invention is to provide a synthetic resin skin material that has good processability when hot-molded using a mold, and that maintains the textured pattern formed on the outermost surface even when laminated with an intermediate layer containing various thermoplastic resins, thereby enabling the formation of a molded product with excellent appearance, and a method for producing the same. Another object of the present invention is to provide a molded article with a good appearance in which the uneven pattern on the skin layer of the synthetic resin skin material is maintained even after hot molding. [Means for solving the problem]

[0008] The means for solving the problem include the following embodiments. <1> A synthetic resin skin material comprising: a base layer containing a thermoplastic resin; an intermediate layer containing a thermoplastic resin and provided on one surface of the base layer; and a skin layer containing a polypropylene resin and provided on the opposite side of the intermediate layer from the base layer, the intermediate layer having an uneven pattern on the surface opposite to the intermediate layer.

[0009] <2> The thermoplastic resin contained in the intermediate layer includes at least one selected from the group consisting of an acrylonitrile-butadiene-styrene copolymer, an acrylic resin, a urethane resin, and a vinyl chloride resin. <1> The synthetic resin skin material according to claim 1. <3> The substrate layer contains at least one selected from the group consisting of an acrylonitrile-butadiene-styrene copolymer, a polycarbonate resin, and a vinyl chloride resin. <1> or <2> The synthetic resin skin material according to claim 1.

[0010] <4> A design layer is further provided between the intermediate layer and the surface layer. <1> ~ <3> 10. The synthetic resin skin material according to claim 9, <5> The design layer is a printing ink layer containing at least one selected from the group consisting of acrylic resin, urethane resin, polyolefin resin, polyamide resin, and vinyl chloride-vinyl acetate copolymer. <4> The synthetic resin skin material according to claim 1.

[0011] <6> A surface treatment layer is further provided on the surface of the surface layer having the uneven pattern. <1> ~ <5> 10. The synthetic resin skin material according to claim 9, <7> The surface treatment layer contains at least one resin selected from the group consisting of acrylic resin, urethane resin, polyolefin resin, polyamide resin, silicone resin, and vinyl chloride-vinyl acetate copolymer. <6> The synthetic resin skin material according to claim 1.

[0012] <8> It is a surface material for heat-molded products. <1> ~ <7> 10. The synthetic resin skin material according to claim 9,

[0013] <9> A method for producing a synthetic resin skin material, comprising the steps of: preparing a skin layer containing a polypropylene resin; forming an intermediate layer using a resin composition containing a thermoplastic resin; forming a base layer using a thermoplastic resin composition containing a thermoplastic resin; laminating the skin layer, the intermediate layer, and the base layer in this order to obtain a laminate; and applying a laminate embossing process to the skin layer side of the obtained laminate using a squeezing roll to form a textured pattern on the surface of the skin layer opposite to the intermediate layer side. <10> The method further includes a step of forming a design layer between the surface layer and the intermediate layer. <9> 1. A method for producing the synthetic resin skin material according to claim 1. <11> The method further includes a step of forming a surface treatment layer on the surface of the surface layer having the uneven pattern. <9> or <10> 1. A method for producing the synthetic resin skin material according to claim 1.

[0014] <12> a molding substrate and a molding material disposed on the surface of the molding substrate; <1> ~ <8> and a molded article having the synthetic resin skin material according to any one of the above. [Effects of the Invention]

[0015] According to an embodiment of the present invention, it is possible to provide a synthetic resin skin material that has good processability when hot-molded using a mold, and that maintains the textured pattern formed on the outermost surface even when laminated with an intermediate layer containing various thermoplastic resins, thereby enabling the formation of a molded product with excellent appearance, and a method for producing the same. According to another embodiment of the present invention, a molded article with a good appearance can be provided in which the uneven pattern on the skin layer of the synthetic resin skin material is maintained even after hot molding. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of a synthetic resin skin material according to the present disclosure. [Figure 2] FIG. 10 is a schematic cross-sectional view showing one embodiment of a synthetic resin skin material further having a design layer. DETAILED DESCRIPTION OF THE INVENTION

[0017] The synthetic resin skin material, the method for producing the synthetic resin skin material, and the molded article according to the present disclosure will be described in detail below. The following description of the components may be based on representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments. In the present disclosure, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower limit and upper limit. In the present disclosure, in the numerical ranges described in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, combinations of preferred aspects are more preferred aspects. In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified. In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0018] In the present disclosure, the term "layer containing a resin" refers to a "layer formed containing a resin that is the main component of the layer." That is, in the present disclosure, the term "layer containing a resin" is used to encompass both a resin layer containing only a resin, and a layer formed from a resin composition that contains, in addition to the resin that is the main component, optional components such as a plasticizer, a colorant, and an ultraviolet absorber. In the present disclosure, the term "resin that is the main component" refers to a resin that is contained in an amount of 60 mass % or more relative to the total amount of the resin composition containing that component. Hereinafter, in this disclosure, polypropylene resin may be abbreviated as PP resin, acrylonitrile-butadiene-styrene copolymer as ABS resin, and polyvinyl chloride resin as PVC resin.

[0019] <Synthetic resin skin material> The synthetic resin skin material of the present disclosure comprises a base layer containing a thermoplastic resin, an intermediate layer containing a thermoplastic resin and provided on one surface of the base layer, and a skin layer containing a polypropylene resin and provided on the surface of the intermediate layer opposite the base layer, the surface opposite the intermediate layer having a textured pattern.

[0020] The synthetic resin skin material of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing one embodiment of the layer structure of a synthetic resin skin material 10 of the present disclosure. The synthetic resin skin material (hereinafter, occasionally referred to as the skin material) 10 comprises, in this order, a base layer (hereinafter, occasionally referred to as the base layer) 12 containing a thermoplastic resin, an intermediate layer (hereinafter, occasionally referred to as the intermediate layer) 14 containing a thermoplastic resin provided on one side of the base layer, and a skin layer (hereinafter, occasionally referred to as the specific skin layer) 16 having an uneven pattern on the side opposite to the intermediate layer 14 and containing a PP resin. 1 has a laminated structure having, in order, a base layer 12, an intermediate layer 14, and a specific skin layer 16, and has an uneven pattern, also called a grain pattern, on the surface of the specific skin layer 16 opposite the side that contacts the intermediate layer 14. When the synthetic resin skin material 10 is placed on a molding substrate (described below) to form a molded article, the side of the specific skin layer 16 having the uneven pattern will be located on the outermost surface of the molded article, and therefore, hereinafter, the side of the specific skin layer 16 having the uneven pattern will sometimes be referred to as the "surface."

[0021] FIG. 2 is a schematic cross-sectional view showing another embodiment of the skin material of the present disclosure. The synthetic resin skin material 20 shown in Fig. 2 further has a design layer 18 that is provided as desired between the intermediate layer 14 and the specific skin layer 16 in Fig. 1. The specific skin layer 16 is located on the surface of the design layer 18 opposite to the surface that contacts the intermediate layer 14, and has an uneven pattern on the surface opposite to the design layer 18 side.

[0022] That is, in the synthetic resin skin material 10 and the synthetic resin skin material 20 shown in FIGS. 1 and 2, the surface of the specific skin layer 16 has an uneven pattern. The shape of the textured pattern is selected appropriately depending on the intended use of the skin material. Generally, various variations such as geometric patterns can be selected. The textured pattern on the surface of the specific skin layer 16 is a pattern that characterizes the appearance of the surface of the molded article made from the skin material.

[0023] The skin material of the present disclosure can be suitably used as a skin material for a molded body formed by hot molding such as insert molding, as will be described later.

[0024] The synthetic resin skin material of the present disclosure has a skin layer that has a textured pattern on one side and that contains a PP resin and has good heat resistance; the textured pattern formed on one side of the skin layer is resistant to deformation due to heat; and there is a high degree of freedom in the selection of thermoplastic resins that can be used for the intermediate layer that is provided on the side of the skin layer opposite the side that has the textured pattern. Furthermore, by laminating the skin layer with an intermediate layer containing a thermoplastic resin, when the synthetic resin skin material of the present disclosure is placed in a mold and molten resin is injected, or when the synthetic resin skin material of the present disclosure is laminated on the surface of a molding substrate and molded in a mold, the intermediate layer, which is easily deformed by heat, mitigates the effects of thermal stress on the skin layer during heat molding, and it is believed that deformation of the uneven pattern formed on the surface of the skin layer is effectively suppressed without impairing the heat moldability of the synthetic resin skin material. Therefore, by using the synthetic resin skin material of the present disclosure, the uneven pattern (grain pattern) formed on the surface of the skin layer can be maintained to a high extent even after heat molding such as insert molding, and therefore the uneven pattern can be imparted to the skin layer independently of the formation of the molded body by heat molding, which has the advantage that it is possible to produce molded bodies having a variety of uneven patterns on their surfaces without changing the molding die.

[0025] Furthermore, a design layer may be provided between the skin layer and the intermediate layer. There are no particular restrictions on the design layer that may be provided as desired, so any desired design can be formed, and the uneven pattern on the surface of the skin layer is maintained even after heat molding, so the resulting molded product has a high degree of freedom in design and good design properties.

[0026] The synthetic resin skin material of the present disclosure has good heat moldability for insert molding and the like, and the textured pattern of the synthetic resin skin material is well maintained on the surface of the molded article obtained after heat molding. Therefore, the synthetic resin skin material of the present disclosure has excellent design properties and good thermal processability, and is therefore suitable for various applications such as vehicle interior materials obtained by laminating it with a molding substrate and then heat molding it.

[0027] The skin material of the present disclosure will be described below in order along with the materials constituting it and the method for producing it.

[0028] (1. Epidermal layer) The skin layer of the skin material of the present disclosure contains a PP resin, which provides the skin layer with good durability and chemical resistance. Furthermore, since the resin has good heat resistance, it is believed that the uneven pattern can be well maintained even when a skin material is brought into contact with the resin molded product and molded under heat.

[0029] The PP resin that can be used for the skin layer is not particularly limited as long as it is a PP resin obtained by polymerizing a propylene monomer as a polymerization component. The PP resin in the present disclosure includes any of a homopolymer, a random copolymer, and a block copolymer. For the skin layer, for example, a general-purpose PP resin (a PP resin whose main component is crystalline isotactic PP) can be used. The skin layer may contain a PP resin, which is a homopolymer synthesized only from propylene monomer, or a copolymer containing propylene as well as other monomers such as ethylene and butene-1. When the skin layer contains two or more types of PP resins, a combination of the above PP resins (homopolymers) or a mixture of a PP resin and a PP copolymer resin containing a copolymer component other than propylene may be used. The skin layer may contain a resin other than PP resin, but the content of PP resin in the total resin components in the skin layer is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more. Examples of resins other than PP resin that can be contained in the skin layer include polyethylene resin and olefin resins other than PP resin.

[0030] The skin layer may contain only one type of PP resin, or two or more types in combination. Examples of two or more types of PP resins include a combination of PP resins with different crystallinity or different degrees of polymerization.

[0031] When the skin layer contains two or more resins, it may be a mixture of two or more PP resins as described above, or may have a laminate structure of two or more resins. For example, the outermost surface of the skin layer, i.e., the surface that faces outward when a synthetic resin skin material is placed on a molded body, can be a layer containing PP resin, and in order to further improve adhesion between the skin layer and an intermediate layer or an optional design layer, the skin layer can have a two-layer structure consisting of a layer containing PP resin and a layer containing, for example, an olefin-based resin other than PP resin (also referred to as other olefin-based resin), with the layer containing the other olefin-based resin positioned on the surface that contacts the intermediate layer or design layer.

[0032] The skin layer may be obtained by molding a PP resin, or a commercially available film may be applied. The method for forming the skin layer is not particularly limited, and any known sheet forming method can be used, such as extrusion, calendaring, or casting.

[0033] From the viewpoint of durability and retention of the textured pattern, the thickness of the skin layer is preferably in the range of 5 μm to 200 μm, and more preferably in the range of 30 μm to 150 μm. Here, the thickness of the skin layer refers to the thickness of the area of ​​the skin layer where the uneven pattern is not formed. The thickness of the skin layer and the thickness of each layer of the synthetic resin skin material described below can be measured by observing a cross section of the synthetic resin skin material cut perpendicular to the surface. Therefore, the thickness of each layer of the synthetic resin skin material in this disclosure refers to the thickness after drying.

[0034] One surface of the skin layer of the skin material of the present disclosure has a textured pattern. In the present disclosure, the textured pattern refers to the presence of regions of different thickness in at least a portion of the skin layer. There are no particular limitations on the textured pattern, and the position and depth of the textured pattern can be selected as desired. Examples of the textured pattern include a geometrically regularly arranged pattern and an irregular pattern similar to natural leather, known as shibori (graining), and are not particularly limited. The depth of the recesses of the uneven pattern formed on the surface of the skin layer can be selected appropriately depending on the intended design of the skin material. Generally, from the viewpoint of the design of the skin material, the depth of the recesses is preferably in the range of 5 μm to 150 μm. From the viewpoint of maintaining the textured pattern formed on the side opposite to the intermediate layer or the optional design layer (described later) in the skin material of the present disclosure, the thickness of the skin layer is preferably greater than the distance between the bottom of the deepest recess of the textured pattern and the top of the protrusion. For example, when forming a textured pattern in which the depth of the recesses is 1 μm or less, the thickness of the skin layer can be about 5 μm. When forming a natural leather-like pattern having shallow and deep recesses with the deep recesses being 2 μm to 5 μm, the thickness of the skin layer is preferably 10 μm or more.

[0035] There are no particular limitations on the method for forming the textured pattern on the surface of the skin layer opposite to the surface on the intermediate layer side, and any known method can be used. Known methods include a method of forming a skin layer on a release paper having a textured pattern, and a method of first forming a skin layer with a smooth surface, and then contacting the surface side of the skin layer with a squeezing roll having a textured pattern to perform laminate embossing to form the textured pattern on the skin layer.

[0036] The method for forming the skin layer on the surface of the intermediate layer or the optional design layer opposite to the surface facing the base layer is arbitrary. For example, a preformed skin layer and the intermediate layer or the optional design layer may be adhered to each other, or after the skin layer is formed, the intermediate layer or the optional design layer may be formed on one surface of the skin layer by the method described below.

[0037] (2. Middle Class) The skin material of the present disclosure has an intermediate layer on the surface of the skin layer that does not have a textured pattern. The intermediate layer contains a thermoplastic resin. The thermoplastic resin contained in the intermediate layer can be appropriately selected from known thermoplastic resins, taking into consideration the intended use of the skin material of the present disclosure, the shape, intended use, design, etc. of the molded article formed using the skin material of the present disclosure. Examples of thermoplastic resins that the intermediate layer may contain include ABS resin, AS resin, acrylic resin such as PMMA, urethane resin, polyvinyl acetate (PVAc), PC, PVC resin, etc. Among these, from the viewpoint of maintaining the textured pattern of the surface layer, it is preferable that the intermediate layer contains at least one resin selected from the group consisting of ABS resin, acrylic resin such as PMMA, urethane resin, and PVC resin. The intermediate layer may contain only one type of thermoplastic resin, or may contain two or more types of thermoplastic resin. The content of the thermoplastic resin in the intermediate layer can be set to 50% by mass to 100% by mass, and is preferably set to the range of 60% by mass to 95% by mass.

[0038] In addition to the thermoplastic resin, the intermediate layer may contain other components, such as known additives, if desired. Examples of other components that the intermediate layer may contain include colorants, processing aids, plasticizers, fillers, lubricants, etc. When the intermediate layer contains other components other than the thermoplastic resin, the content of the other components is preferably set within a range that does not reduce the thermal processability of the intermediate layer.

[0039] -Other ingredients: coloring agent- The intermediate layer may contain a colorant. When a molded article is produced using the skin material of the present disclosure, the inclusion of a colorant in the intermediate layer can suppress the influence of the molding substrate used on the appearance of the molded article, and can impart depth to the color of the synthetic resin skin material and, ultimately, the molded article in which the synthetic resin skin material is disposed.

[0040] When the intermediate layer contains a colorant, the colorant is not particularly limited, and dyes, pigments, etc. can be appropriately selected and used. Examples of colorants include inorganic pigments such as titanium white (titanium dioxide), zinc white, ultramarine, cobalt blue, red iron oxide, vermilion, yellow lead, titanium yellow, and carbon black; organic pigments or dyes such as quinacridone, permanent red 4R, isoindolinone, Hansa Yellow A, phthalocyanine blue, indanthrene blue RS, and aniline black; metal pigments selected from the group consisting of foil powders of metals such as aluminum and brass; and pearlescent (pearl) pigments selected from the group consisting of foil powders of titanium dioxide-coated mica and basic lead carbonate. Among these, pigments that are colorants with excellent weather resistance and durability are preferred.

[0041] When the intermediate layer contains a colorant, it may contain only one type of colorant, or may contain two or more types of colorants for the purpose of color matching or the like. There are no particular restrictions on the content of the colorant in the resin composition used to form the intermediate layer, and the type and content of the colorant to be used may be selected appropriately depending on the desired hue of the skin material, the hiding power of the molding substrate, and the like. From the viewpoint of uniformity of the layer, the content of the colorant is preferably 50 mass % or less of the total solid content of the resin composition used to form the intermediate layer, where the solid content refers to the total amount of all components of the resin composition constituting each layer, such as the intermediate layer, excluding the solvent.

[0042] The thickness of the intermediate layer is preferably in the range of 30 μm to 300 μm, and more preferably in the range of 50 μm to 200 μm. When the thickness is in this range, the thermal stress on the skin layer is alleviated when the synthetic resin skin material is heated to form a molded article, and the uneven pattern is better retained.

[0043] The method for forming the intermediate layer is not particularly limited, and any known sheet forming method can be used, such as an extrusion method using a T-die or the like, a calendar method, or a casting method. Among these, the calendering method is preferred because of the ease of production and the ease of maintenance of the equipment. In particular, when the intermediate layer contains a colorant, a softened resin and a solid colorant can be supplied to a calender roll and formed into a sheet or film, making it possible to easily produce intermediate layers containing various colorants. Furthermore, compared with molding methods such as extrusion, the application of the calendering method makes it easier to clean the interior of the equipment, which is necessary when changing the type or amount of colorant added. Therefore, by applying the calendering method when forming a product containing a colorant as an intermediate layer, it is possible to easily produce various base layers with desired hues, and the method is also suitable for small-lot production of synthetic resin skin materials.

[0044] (3. Base material layer) The skin material of the present disclosure has a substrate layer on the surface of the intermediate layer opposite to the skin layer side. The base layer contains a thermoplastic resin. There are no particular restrictions on the thermoplastic resin that can be used for the base layer, and the base layer can be appropriately selected from known thermoplastic resins in consideration of various conditions such as affinity with the resin constituting the molded article to be applied and stretchability when molded. Examples of thermoplastic resins that can be used for the base layer include polyethylene (PE), PP resin, PVC resin, polystyrene (PS), polyvinyl acetate (PVAc), polyurethane (urethane resin), ABS resin, acrylonitrile-styrene copolymer (AS resin), polycarbonate (PC), and polymethyl methacrylate (PMMA). Among these, from the viewpoint of processability, the base layer is preferably made of acrylic resins such as PE, PP resin, PVC resin, PS, PVAc, urethane resin, ABS resin, AS resin, PC, and PMMA, and from the viewpoint of effectively suppressing breakage due to melting during heat molding of the synthetic resin skin material placed on the surface of the base, the thermoplastic resin contained in the base layer is more preferably ABS resin, AS resin, PC, PVC resin, PC / ABS, etc. The substrate layer may contain only one type of thermoplastic resin, or may contain two or more types of thermoplastic resin. The content of the thermoplastic resin in the base layer can be set to 70% by mass to 100% by mass, and is preferably set to the range of 60% by mass to 95% by mass.

[0045] The substrate layer may contain, in addition to a thermoplastic resin, various components other than the thermoplastic resin, such as a colorant, a processing aid, a plasticizer, a filler, and a lubricant.

[0046] -Other ingredients: coloring agent- In particular, the substrate layer preferably contains a colorant, which can prevent the substrate from affecting the appearance of the molded body when the synthetic resin skin material is disposed on the surface of the resin that serves as the substrate for the molded body to produce the molded body. The colorants that can be used in the base layer are the same as those that can be used in the intermediate layer, and the desired color can be selected depending on the purpose. When a colorant is used in the base layer, the preferred content of the colorant can be appropriately selected depending on the purpose of the skin material.

[0047] When the base layer contains a colorant, the colorant is not particularly limited, and dyes, pigments, etc. can be appropriately selected and used. The colorants that can be used in the base layer are the same as those that can be used in the intermediate layer, and a desired colorant may be selected depending on the purpose.

[0048] When the base layer contains a colorant, it may contain only one type of colorant, or may contain two or more types of colorants for the purpose of color matching or the like. Of these, black pigments such as carbon black, aniline black, and perylene black are preferred as colorants contained in the substrate layer, from the viewpoint of being able to effectively conceal the molded substrate. There are no particular restrictions on the content of the colorant in the resin composition used to form the base layer, and the type and content of the colorant to be used may be selected appropriately depending on the desired hue of the synthetic resin skin material, the hiding power of the molded base material, and other factors. When the base layer contains a colorant, the content of the colorant is generally preferably 1% by mass to 50% by mass, and more preferably 2% by mass to 30% by mass, relative to the total solid content of the resin composition constituting the base layer, from the viewpoint of uniformity of the base layer to be formed.

[0049] The thickness of the substrate layer is preferably in the range of 50 μm to 500 μm, and more preferably in the range of 100 μm to 400 μm. When the thickness is in this range, breakage due to melting of the synthetic resin skin material is effectively suppressed when a molded article is formed by thermal processing using the synthetic resin skin material, and further, the hiding power of the molding substrate used in the molded article is improved.

[0050] The method for forming the substrate layer is not particularly limited, and any known sheet forming method can be applied. The substrate layer can be formed by the same method as that for the intermediate layer described above, such as extrusion, calendaring, casting, etc. Among these, the calendering method is also preferred for forming the base layer in terms of ease of production and ease of maintenance of the equipment. In particular, when the base layer contains a colorant, as explained in the method for forming the intermediate layer, base layers containing various colorants can be easily produced. As with the formation of the intermediate layer, the application of the calendering method to the formation of the base layer makes it possible to easily produce a variety of base layers with desired hues, and is also suitable for small-lot production of synthetic resin skin materials.

[0051] As described above, the thickness of each layer in the synthetic resin skin material of the present disclosure is preferably in the range of 5 μm to 200 μm for the skin layer, 30 μm to 300 μm for the intermediate layer, and 50 μm to 500 μm for the base layer. The preferred thickness of the design layer, which is an optional layer, will be described later.

[0052] (4. Other layers) The synthetic resin skin material may further have other layers in addition to the substrate layer, intermediate layer and skin layer described above, as long as the effects are not impaired. Examples of other layers include a design layer, a surface treatment layer, an adhesive layer, and a primer layer.

[0053] (4-1. Design layer) The synthetic resin skin material may further have a design layer on the surface of the intermediate layer opposite to the substrate layer side. The design layer is a layer that imparts a design to the synthetic resin skin material, and may be a printed layer formed by printing, a colored layer containing a colorant, or a layer that combines these. Among these, from the viewpoint of freedom of design, a layer formed by printing ink is preferred as the design layer. In the skin material of the present disclosure, there are no particular limitations on the design layer, and various design layers can be formed as desired depending on the intended use of the skin material, thereby imparting the desired, highly design-oriented appearance to the molded article.

[0054] The design layer can be formed, for example, by a printing method on the surface of the intermediate layer or the aforementioned surface layer. Examples of printing methods for forming the design layer include a method of forming the design layer by a known printing method using a printing ink containing a resin. From the viewpoint of being able to form a clear printed image, the resin-containing printing ink preferably contains at least one resin selected from acrylic resin, urethane resin, polyolefin resin, polyamide resin, and vinyl chloride-vinyl acetate copolymer, and more preferably contains at least one resin selected from acrylic resin, urethane resin, and vinyl chloride-vinyl acetate copolymer. There are no particular limitations on the printing method for the design layer, and any printing method can be applied, such as gravure printing (intaglio printing), letterpress printing, offset printing, inkjet printing, screen printing, etc., with gravure printing, screen printing, inkjet printing, etc. being preferred. The design layer formed by a printing method may be a discontinuous layer including areas where the printing ink is adhered, or may be a continuous, uniform layer made of the printing ink.

[0055] Another embodiment of the colored layer is a layer formed of a resin composition containing any colorant, such as a design layer formed by molding a resin composition containing an acrylic resin and a colorant selected from the colorants listed above as usable for the base layer into a film by a calendaring method, an extrusion method, a casting method, or the like.

[0056] Specific examples of acrylic resins that can be used to form the design layer include polymers or copolymers of methacrylic acid or methacrylic acid esters, such as PMMA, and copolymers of alkyl methacrylate, alkyl acrylate, and styrene. From the standpoint of formability, mixtures of copolymers of alkyl methacrylate, alkyl acrylate, and styrene and copolymers of methyl methacrylate and methyl acrylate are preferred.

[0057] When the skin material of the present disclosure has a design layer, the thickness of the design layer is preferably in the range of 1 μm to 10 μm, and more preferably in the range of 2 μm to 8 μm. Having a thickness within this range allows the desired design to be imparted to the synthetic resin skin material, and maintains good correlation between the skin layer and the intermediate layer when the synthetic resin skin material is used to form a molded product by thermal processing, thereby better retaining the textured pattern of the skin layer. When forming a design layer, the thickness ratio of the skin material layer is preferably in the range of 1 to 10 when the thickness of the intermediate layer is 100. As described above, the thickness of the skin layer is in the range of 15 to 55 when the thickness of the intermediate layer is 100, and it is therefore preferable that the design layer is thinner than the skin layer.

[0058] (4-2. Surface treatment layer) The skin material of the present disclosure may further include a surface treatment layer. In one embodiment, the surface treatment layer is provided on one side of the skin layer, opposite the intermediate layer side (the surface of the skin layer). By further providing the surface treatment layer to the skin material, it is possible to impart additional functions to the skin material, such as imparting any desired good feel to the skin material, further improving the appearance, and further improving the durability.

[0059] The surface treatment layer contains at least a resin, such as at least one resin selected from an acrylic resin, a urethane resin, a polyolefin resin, a polyamide resin, a silicone resin, and a vinyl chloride-vinyl acetate copolymer, and from the viewpoint of further improving abrasion resistance and tactile feel, it is more preferable that the surface treatment layer contains at least one resin selected from a urethane resin and an acrylic resin. The surface treatment layer may contain only one type of resin, or may contain two or more types of resin.

[0060] In addition to the resin, the surface treatment layer may contain a crosslinking agent, an organic filler, an inorganic filler (for example, silica particles), a lubricant, a flame retardant, an antioxidant, an antistatic agent, and the like. For example, when the surface treatment layer is provided for the purpose of improving the tactile feel of the skin material, it may contain organic particles as a filler, a colorant for improving design, or the like as a tactile feel improver, if desired. Furthermore, for the purpose of further improving abrasion resistance, a surface treatment layer containing a crosslinked structure can be formed by applying a composition for forming a surface treatment layer containing a resin or a resin precursor and a crosslinking agent to a skin layer, and then applying energy to crosslink the composition. The surface treatment layer can be formed by applying a resin composition for forming the surface treatment layer, which contains the resin described above and optional components used as desired, to the surface side of the skin layer by a printing method. The method for producing the surface treatment layer will be described in detail later.

[0061] From the viewpoint of further improving the strength of the surface of the skin material, the thickness of the surface treatment layer is preferably 1 μm to 30 μm, and more preferably 2 μm to 20 μm.

[0062] (4-3. Adhesive layer) The skin material of the present disclosure may have an adhesive layer on the surface of the substrate layer opposite the intermediate layer side, in order to improve adhesion to the molded substrate. The adhesive layer can be formed by applying at least one of a known adhesive and a known pressure-sensitive adhesive to the surface of the base layer opposite to the intermediate layer side. The adhesive used to form the adhesive layer that is optionally provided on the synthetic resin skin material is not particularly limited and may be selected appropriately depending on the type of molding substrate. Suitable adhesives include (1) two-component curing polyester adhesives, (2) two-component curing urethane adhesives, and (3) two-component curing acrylic adhesives. The thickness of the adhesive layer is preferably in the range of 5 μm to 50 μm.

[0063] When forming an adhesive layer on a base material layer, a primer layer, as described in detail below, can be formed between the base material layer and the adhesive layer in order to improve adhesion, and the adhesive layer can be formed by applying at least one of an adhesive and a pressure-sensitive adhesive to the surface of the formed primer layer. The adhesive layer can be applied to the substrate layer or the primer layer by any known method such as a transfer method or a coating method. From the viewpoint of easily forming an adhesive layer of uniform thickness, the transfer method is preferably used.

[0064] (4-4. Primer layer) In the skin material of the present disclosure, when an adhesive layer is provided adjacent to the substrate layer, a resin layer acting as a primer layer may be provided between the adhesive layer and the substrate layer in order to improve adhesion between the substrate layer and the resin molded article. The primer layer can be formed by a coating method. More specifically, the resin for forming the primer layer is dissolved in an appropriate solvent, and the solution is applied to the surface of the substrate layer opposite to the surface of the skin layer, followed by drying to form the primer layer. The resin contained in the primer layer is preferably formed using a resin such as a polyester resin, from the viewpoint of having good affinity with the thermoplastic resin contained in the base material layer and the adhesive contained in the adhesive layer provided adjacent thereto. There is no particular limitation on the amount of resin layer to be applied, and it can be selected appropriately depending on the purpose. Generally, from the viewpoint of improving adhesiveness, it is 1 g / m 2 ~5g / m2 It is preferable that the range is 2 g / m 2 ~3g / m 2 It is more preferable that the range is:

[0065] The skin material of the present disclosure has, on its outermost surface, a skin layer that is excellent in transparency and durability and that retains its textured pattern well when heated, and also has an intermediate layer and a substrate layer that are excellent in thermal processability. Therefore, the skin material of the present disclosure retains the textured pattern well even after hot molding. Therefore, it is suitable for use as a skin material for molded articles that require hot molding. The resulting molded articles reflect the design characteristics of the synthetic resin skin material, have an excellent appearance, and are also excellent in durability, such as solvent resistance. The skin material of the present disclosure is preferably used as a skin material for heat-molded products. That is, the skin material of the present disclosure can be used in a variety of applications as a synthetic resin skin material that imparts design to the surface of a molded product that requires heat processing, i.e., as a skin material for heat-molded products.

[0066] <Method of manufacturing synthetic resin skin material> There are no particular limitations on the method for producing the synthetic resin skin material of the present disclosure, and any known production method can be used as appropriate. Among these, it is preferable to produce the synthetic resin skin material by the method for producing the synthetic resin skin material of the present disclosure, which will be described in detail below.

[0067] The method for producing a synthetic resin skin material of the present disclosure includes the steps of: preparing a skin layer containing a polypropylene resin (Step A); forming an intermediate layer using a resin composition containing a thermoplastic resin (Step B); forming a base layer using a thermoplastic resin composition containing a thermoplastic resin (Step C); laminating the skin layer, intermediate layer, and base layer in this order to obtain a laminate (Step D); and applying a laminate embossing process to the skin layer side of the obtained laminate using a squeezing roll to form a textured pattern on the surface of the skin layer opposite the intermediate layer side (Step E). The method for producing a synthetic resin skin material of the present disclosure may further include an optional step such as a step (step F) of forming a design layer between the skin layer and the intermediate layer.

[0068] (Process A) In step A, a skin layer containing a PP resin is prepared. Preparing the skin layer includes both forming a skin layer containing a PP resin using a resin composition for forming a skin layer containing a PP resin, and procuring a commercially available film containing a PP resin as the skin layer. In the step A, when the surface layer is formed using a resin composition for forming a surface layer containing a PP resin, the surface layer can be formed by a calendering method, an extrusion method, a casting method or the like. When forming a skin layer having a laminated structure, step A can be a step of forming the skin layer by forming two or more resins, at least one of which contains a PP resin, into a laminated film by a co-extrusion method or the like. Step A also includes preparing a commercially available PP resin-containing film as the skin layer, which contains a PP resin, as described above in the description of the skin material of the present disclosure. The PP resin used to form the skin layer can be any of the resins listed in the skin layer section of the skin material above. The thickness of the skin layer to be formed is preferably 5 μm to 200 μm, more preferably 30 μm to 150 μm.

[0069] (Process B) In step B, first, an intermediate layer containing a thermoplastic resin is formed using a resin composition for forming an intermediate layer containing a thermoplastic resin by a known method such as a calendaring method, an extrusion method, or a casting method. Among these, from the viewpoint of processability, it is preferable to form the intermediate layer by a calendaring method. By forming the intermediate layer by a calendaring method, it is possible to form an intermediate layer with a uniform thickness more easily than, for example, a melt extrusion method. In addition to the thermoplastic resin, the intermediate layer can contain other components such as a colorant and a processing aid depending on the purpose. When the intermediate layer contains a thermoplastic resin and other components used as desired, a resin composition for forming the intermediate layer containing the thermoplastic resin and the other components can be prepared and molded into a film. When the intermediate layer contains a colorant, applying a calendaring method to form the layer makes it easy to clean the inside of the device, which is necessary when changing the type or amount of colorant used in the intermediate layer. An example of a method for forming an intermediate layer using a thermoplastic resin and a pigment as a colorant includes adding a predetermined amount of pigment to a thermoplastic resin, heating and mixing the resulting mixture with a hot mixing roll to obtain a colored resin composition for forming an intermediate layer, and then forming an intermediate layer using the resulting colored resin composition by a calendaring method. When a colorant is not used, the same method as above can be used, except that the step of adding the pigment is not performed. The thermoplastic resin used to form the intermediate layer may be any of the thermoplastic resins exemplified as those that can be contained in the intermediate layer in the skin material of the present disclosure described above, and among these, ABS resin, acrylic resin, urethane resin, and PVC resin are preferred. The thickness of the intermediate layer to be formed is preferably 30 μm to 300 μm, more preferably 50 μm to 200 μm.

[0070] (Process C) In step C, a base layer is formed using a resin composition for forming a base layer containing a thermoplastic resin by a known method such as a calendar method, an extrusion method, a casting method, etc. Among these, from the viewpoint of processability, it is preferable to form the base layer by a calendar method. The method for forming the base layer by the calendering method can be carried out in the same manner as the method for forming the intermediate layer using a thermoplastic resin in step B. When a colorant is to be contained in the base layer, the base layer can be formed by a method including, as in step B, adding a predetermined amount of pigment to a thermoplastic resin for forming the base layer, heating and mixing the mixture with a hot mixing roll to obtain a colored resin composition for forming the base layer, and forming the base layer using the obtained colored resin composition by a calendaring method. The thermoplastic resin used to form the base layer can be any of the thermoplastic resins exemplified as those that can be contained in the base layer in the skin material of the present disclosure described above, and among these, ABS resin, PC resin, and PVC resin are preferred. The thickness of the substrate layer to be formed is preferably 50 μm to 500 μm, and more preferably 100 μm to 400 μm.

[0071] The steps A, B, and C may be carried out in any order, and each step may be carried out independently.

[0072] (Process D) In step D, the skin layer prepared in step A, the intermediate layer formed in step B, and the base layer formed in step C are laminated in this order to obtain a laminate. The laminate can be formed by laminating an intermediate layer and a base layer in this order on one side of a skin layer. Each layer is heated and pressurized by passing it between a pair of rolls, and a laminate in which the skin layer, intermediate layer, and base layer are in close contact with each other is formed. The process of forming a laminate in which the layers are in close contact with each other by passing it between a pair of rolls and applying heat and pressure is called lamination.

[0073] (Process E) In step E, the surface layer side of the laminate obtained in step D, in which adjacent layers are in close contact with each other, is subjected to laminate embossing using a squeeze roll, to form a textured pattern on the surface of the surface layer opposite the intermediate layer side. Steps D and E can be performed simultaneously. That is, the intermediate layer and the base layer are laminated in this order on one surface of the skin layer, and then the laminate is embossed using a squeeze roll, so that the layers are bonded under heat and pressure and the desired textured pattern is formed on the surface of the skin layer simultaneously. In the present disclosure, lamination refers to, as described above, passing a plurality of resin-containing layers between a pair of rolls that perform thermocompression bonding to bond them together to form a laminate. In this disclosure, the laminate embossing process using a squeeze roll in step E refers to using a squeeze roll as one of a pair of embossing rolls used for thermal compression bonding, and squeezing the surface of the laminate that comes into contact with the squeeze roll (the surface of the skin layer in the case of the skin material of this disclosure) with the squeeze roll to form a textured pattern on the surface. In step E, the laminate embossing process can be performed in an arrangement in which the squeeze roll is located on the skin layer side and the smooth roll is located on the base layer side. This method allows the lamination of each layer and the formation of the textured pattern in the skin layer to be carried out sequentially or simultaneously in a single process.

[0074] By laminating and embossing using a squeezing roll on which an arbitrary uneven pattern has been formed in advance on the surface of the skin layer, the lamination of multiple resin-containing films and squeezing (forming the uneven pattern) onto one surface of the resin-containing film are carried out in one process, and an uneven pattern of any design, such as a natural leather-like uneven pattern, is transferred to the top surface of the skin layer in the formed synthetic resin skin material. By selecting the shape of the uneven pattern to be formed on the squeezing roll, an uneven pattern having any desired uneven shape can be formed on the surface of the synthetic resin skin material. The heating temperature in the laminate embossing process is preferably set to a temperature condition that brings the surface temperature of the laminate to 130°C to 200°C.

[0075] The method for forming the textured pattern on the surface layer is not limited to step E. As described above, a method may also be used in which a layer made of a resin composition for forming a surface layer is extruded onto release paper on which a textured pattern has already been formed, and the textured pattern formed on the release paper is transferred to the surface of the resin composition layer for forming a surface layer that comes into contact with the release paper.

[0076] The method for producing a surface according to the present disclosure may include any optional step in addition to the above steps A, B, C, D, and E, as necessary. Optional steps include, for example, a step of forming a design layer between the surface layer and the intermediate layer (step F), and a step of forming a surface treatment layer on the surface of the surface layer having the textured pattern (step G).

[0077] (Process F) The method for producing a skin material according to the present disclosure may further include an optional step of forming a decorative layer between the skin layer prepared in step A and the intermediate layer formed in step B. Step F is a step of forming a design layer on one side of the surface layer prepared in step A or the intermediate layer formed in step B above. Methods for forming a design layer include, for example, a method in which a pre-formed design layer containing a thermoplastic resin is adhered to one side of the surface layer or intermediate layer, and a method in which printing is performed on one side of the surface layer or intermediate layer using a printing ink containing a resin. In other words, for design layers containing patterns, it is preferable to apply a printing method using printing ink, and for design layers that are colored layers, a method can be applied in which a resin composition for forming a design layer containing a colorant is molded into a film using a known method to form the design layer. Resins contained in printing inks include acrylic resins, urethane resins, polyolefin resins, polyamide resins, vinyl chloride-vinyl acetate copolymers, etc. The printing inks can contain one or more of the above resins.

[0078] Among these, it is preferable to apply a printing method in which a design layer is formed by printing, since this method allows for a high degree of freedom in design. The printing method is a method of printing a known design using printing ink containing a resin, and examples of such a method include printing the resin-containing printing ink using a known printing method, such as gravure printing (intaglio printing), letterpress printing, offset printing, inkjet printing, and screen printing. Specifically, the printing method may involve printing one side of the skin layer by gravure printing using a printing ink containing an acrylic resin. By adjusting the size of the engraving on the print roll used for gravure printing, it is possible to adjust the amount of printing ink applied during printing, and to form a design layer with a variety of designs. The design layer, which is an optional layer, can be formed independently on one side of the skin layer or intermediate layer as desired, allowing the formation of a layer having a desired design with any hue and design. Thus, by providing a design layer, it is possible to impart various designs to the skin material of the present disclosure according to the purpose. The thickness of the design layer is preferably 1 μm to 10 μm, more preferably 2 μm to 8 μm, from the viewpoint of being able to impart a design with excellent appearance to the surface layer.

[0079] (Process G) The method for producing a skin material according to the present disclosure can further include an optional step (step G) of forming a surface treatment layer on the surface of the skin layer on the side having the textured pattern. Step G is a step of forming a surface treatment layer on the surface of the skin layer (the surface of the skin layer opposite to the intermediate layer side) for the purpose of improving the feel, durability, and the like. Step G is carried out by applying a composition for forming a surface treatment layer, which contains a resin and, if desired, further contains other optional components, to the surface of the skin layer. The composition for forming the surface treatment layer can be applied by appropriately applying a known method. The surface treatment layer may be formed by, for example, a method of applying a composition for forming a surface treatment layer by gravure printing, or a method of applying the composition by a coating device such as a reverse coater or a direct coater. Among these, the gravure printing method is preferred from the viewpoint of forming a more uniform layer. The details of the surface treatment layer are as described above. The thickness of the surface treatment layer is preferably 1 μm to 30 μm, more preferably 2 μm to 20 μm, from the viewpoint of further improving the strength, durability, etc. of the surface of the skin material.

[0080] <Molded body> The synthetic resin skin material of the present disclosure described above is suitably used for the purpose of imparting a design to the surface of a molded article when the article is produced by hot molding. The molded article of the present disclosure is a molded article having a molding substrate and the above-described synthetic resin skin material of the present disclosure disposed on the surface of the molding substrate.

[0081] The resin contained in the molding substrate used in the manufacturing process of the molded article is not particularly limited as long as it is a resin that is generally used for the purpose of obtaining a molded article by heat molding. Resins contained in the molded body substrate are preferably ABS resin, PC resin, polyethylene (PE) resin, PP resin, a mixture of PC resin and ABS resin (PC / ABS), etc., and more preferably ABS resin, PC resin, PE resin, PP resin, etc.

[0082] The molded article can be obtained by contacting the skin material of the present disclosure with a molding substrate and molding the resulting material under heat. There are no particular limitations on the method of thermoforming, and known methods such as injection molding, insert molding, extrusion, calendaring, and casting can be used as the thermoforming method. Examples of methods for producing a molded body include an insert molding method in which a skin material of the present disclosure is placed in a mold, and then a heated and melted resin that will become the molding substrate is injected into the mold to form the mold; a method in which a skin material of the present disclosure is placed on the surface of a molding substrate that may be preformed in advance, or a method in which a skin material is placed in a mold, a molding substrate is placed, and then the resulting material is heated and molded in the mold; In the case of insert molding, molding is performed by heating up to the melting temperature of the resin that is the molding substrate. When a skin material is placed on the surface of the molding substrate and heat molding is performed, the heating temperature condition is preferably in the range of 90°C to 200°C.

[0083] The skin material of the present disclosure has good heat moldability, and also retains well the textured pattern formed on the surface of the skin layer even after heat molding using a molten resin, such as insert molding. Therefore, the molded article of the present disclosure maintains the uneven pattern of the skin layer of the skin material, and has excellent design. Furthermore, the skin material of the present disclosure is remarkably effective when applied to obtain a molded article using an insert molding method, which is usually difficult to maintain the design layer or the textured surface pattern.

[0084] The synthetic resin skin material of the present disclosure can be produced by a simple method, has excellent appearance and durability, and is suitable for use as a skin material for hot molding. Therefore, it can be suitably used in a variety of fields, such as interior and exterior materials for automobiles, interior parts for railway cars and aircraft, furniture, shoes, footwear, bags, interior and exterior components for building decoration, and clothing coverings and linings. Furthermore, the molded article of the present disclosure, which is molded with the skin material of the present disclosure disposed thereon, has excellent design properties. [Example]

[0085] The synthetic resin skin material, its manufacturing method, and molded article of the present disclosure will be specifically described below using examples, but the present disclosure is not limited to the following specific examples, and various modifications are possible.

[0086] (Manufacturing synthetic resin skin materials) Example 1 First, a skin layer was prepared by using a polypropylene resin film (Pylen (registered trademark) P1111 (product name), Toyobo Co., Ltd., thickness 100 μm) (Step A).

[0087] Next, 2 kg of pigment (carbon black) was added to 100 kg of ABS resin (TM-30G6 (product name) Techno UMG Co., Ltd.), and while heating at 200°C, the mixture was formed into a sheet using a calendar method so that the thickness after drying would be 100 μm, thereby obtaining an intermediate layer (Step B).

[0088] In a separate step from step B, 2 kg of pigment (carbon black) was added to 100 kg of ABS resin (TM-30G6 (trade name), Techno UMG Co., Ltd.), and the mixture was heated to 200°C and formed into a sheet using a calendar method so that the thickness after drying would be 200 μm, thereby obtaining a substrate layer (step C).

[0089] A laminate was obtained by laminating the surface layer prepared in step A and the intermediate layer formed in step B in this order. The substrate layer prepared in step C was attached to the intermediate layer side of the obtained laminate, and laminate embossing was performed. A pair of squeeze rolls was used, with the squeeze roll side in contact with the surface layer and the smooth roll with the substrate layer side, to bring the layers of the surface layer / intermediate layer / substrate layer laminate into close contact under conditions where the surface temperature of the laminate was 140°C. Furthermore, a textured pattern was formed on the surface of the surface layer opposite the intermediate layer side by the squeeze rolls. The depth of the recesses in the textured pattern was 100 μm (steps D and E).

[0090] A urethane resin (YL454UR Varnish (trade name), Toyo Ink Co., Ltd.) was applied to the surface of the skin layer of the laminate, and after application, the laminate was heated at 80°C for 1 minute using a dryer to form a surface treatment layer with a thickness of 10 μm (step G), thereby obtaining the skin material of Example 1.

[0091] Example 2 A polypropylene resin film (non-oriented polypropylene film RXC-22 (trade name), Mitsui Chemicals Tocello Co., Ltd., thickness 100 μm) was prepared as a surface layer (Step A). Next, 2 kg of pigment (carbon black) was added to 100 kg of PVC resin (Kanevinyl (registered trademark) S1008 (product name), Kaneka Corporation), and while heating at 200°C, the mixture was formed into a sheet by a calendaring method so that the thickness after drying would be 100 μm, thereby obtaining an intermediate layer (Step B). In a separate step from step B, 2 kg of pigment (carbon black) was added to 100 kg of polycarbonate resin (Panlite (registered trademark) L-1225Y (trade name), Teijin Limited), and the mixture was heated to 200°C and formed into a sheet by a calendaring method so that the thickness after drying would be 200 μm, thereby obtaining a substrate layer (step C).

[0092] A textured pattern with a recess depth of 100 μm was formed on the surface of the skin layer opposite to the intermediate layer side of the skin layer / intermediate layer / base layer laminate in the same manner as in Example 1, except that the skin layer prepared in step A, the intermediate layer formed in step B, and the base layer formed in step C were used. Thereafter, a surface treatment layer was formed on the surface of the skin layer in the same manner as in step G of Example 1, and a skin material of Example 2 was obtained.

[0093] Example 3 In Example 1, after step C, a printing ink containing an acrylic resin (VTP-NT (trade name), DIC Graphics Corporation) was applied to the surface of the intermediate layer side of the surface layer to form a design layer with a thickness of 5 μm after drying (step F). Next, a laminate having the design layer formed in step F and the intermediate layer formed in step B were laminated in this order on the surface of the skin layer and the intermediate layer side of the skin layer prepared in the same manner as in step A of Example 1, to obtain a laminate. The base layer prepared in step C in the same manner as in Example 1 was attached to the intermediate layer side of the obtained laminate, and the layers were adhered in the same manner as in Example 1. Furthermore, a textured pattern was formed on the surface of the skin layer opposite the design layer side using a squeezing roll, forming a textured pattern with recesses 100 μm deep on the surface of the skin layer opposite the design side of the skin layer of the skin layer / design layer / intermediate layer / base layer laminate. Then, a surface treatment layer was formed on the surface of the skin layer in the same manner as in step G of Example 1, to obtain the skin material of Example 3.

[0094] Example 4 In Example 2, after step C, a printing ink containing an acrylic resin (VTP-NT (trade name), DIC Graphics Corporation) was applied to the surface of the intermediate layer side of the surface layer to form a design layer with a thickness of 5 μm after drying (step F). Next, a laminate having the design layer formed in step F and the intermediate layer formed in step B were laminated in this order on the surface of the skin layer and the intermediate layer side of the skin layer prepared in the same manner as in step A of Example 2, to obtain a laminate. A base layer prepared in the same manner as in step C of Example 2 was attached to the intermediate layer side of the obtained laminate, and the layers were adhered together in the same manner as in Example 2. Furthermore, a textured pattern with a recess depth of 100 μm was formed on the surface of the skin layer / design layer / intermediate layer / base layer laminate opposite the design side of the skin layer. A surface treatment layer was then formed on the surface of the skin layer in the same manner as in step G of Example 1, to obtain the skin material of Example 4.

[0095] Example 5 The skin material of Example 5, which was a laminate of skin layer / design layer / intermediate layer / base layer and had a textured pattern with recesses 100 μm deep on the surface of the skin layer opposite the design side, was obtained in the same manner as Example 3, except that step G was not performed on the skin material of Example 3 and the surface treatment layer was not formed.

[0096] Example 6 The skin material of Example 6, which was a laminate of skin layer / design layer / intermediate layer / base layer and had a textured pattern with recesses 100 μm deep on the surface of the skin layer opposite the design side, was obtained in the same manner as Example 4, except that step G was not performed on the skin material of Example 4 and the surface treatment layer was not formed.

[0097] Comparative Example 1 The skin material of Comparative Example 1 was obtained in the same manner as in Example 3, except that the polypropylene resin film used as the skin layer in Example 3 (Pylen (registered trademark) P1111 (trade name), Toyobo Co., Ltd., thickness 100 μm) was replaced with a polymethyl methacrylate resin film (Acriplene (registered trademark) Film HBS010P (trade name), Mitsubishi Chemical Corporation).

[0098] Comparative Example 2 A skin material of Comparative Example 2 was obtained in the same manner as in Example 3, except that the polypropylene resin film used as the skin layer in Example 3 (Pylen (registered trademark) P1111 (trade name), Toyobo Co., Ltd., thickness 100 μm) was replaced with a fluororesin film (FT-50Y (trade name), Kureha Extron Co., Ltd.).

[0099] Comparative Example 3 In Example 3, instead of the ABS resin (TM-30G6 (trade name) Techno UMG Co., Ltd.) used in forming the intermediate layer (step B), a polypropylene resin (Pylen (registered trademark) P1111 (trade name) Toyobo Co., Ltd.) was used, and molded into a sheet to a thickness of 100 μm to obtain an intermediate layer. Furthermore, a skin material of Comparative Example 3 having a layer structure of surface treatment layer / skin layer / design layer / intermediate layer was obtained in the same manner as Example 3, except that the formation of the base layer, which is step C of Example 3, was not performed.

[0100] The resulting skin materials of the Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1 below. A skin material having a fluororesin-containing skin layer, as described in Patent Document 1, was prepared with the following configuration and evaluated in the same manner as a reference example. The results are shown in Table 1.

[0101] [Reference example] A reference skin material was obtained in the same manner as in Example 3, except that the polypropylene resin film (Pylen (registered trademark) P1111 (trade name), Toyobo Co., Ltd., thickness 100 μm) used in forming the skin layer (step A) in Example 3 was replaced with a fluororesin film (FT-50Y (trade name), Kureha Extron Co., Ltd.).

[0102] (Evaluation of synthetic resin skin materials) (1. Evaluation of synthetic resin skin materials: Retention of textured patterns) For the synthetic resin skin materials obtained in the Examples, Comparative Examples, and Reference Examples, the surface roughness of the skin layer on which the uneven pattern was formed was measured using a surface roughness meter (Surfcom 130A, manufactured by Tokyo Seimitsu Co., Ltd.). The synthetic resin skin material was then heated until the surface of the skin layer reached 130°C, maintained at that temperature for 1 minute, and then cooled to room temperature (25°C). The surface roughness of the skin layer surface after heating and cooling was measured under the same conditions as before heating, and the surface roughness before and after heating was compared to calculate the recess depth retention rate using the following formula. Retention rate of recess depth (%) = [depth of recess after heating / depth of recess before heating] x 100 In evaluating the retention of the textured pattern of a synthetic resin skin material after heating, if the recess depth retention rate is 70% or more, it is at a level that can be used practically for molded bodies to be heat-molded, and if the recess depth retention rate is less than 70%, it is at a level that is problematic for practical use. In particular, if the recess depth retention rate is 30% or less, it is at a level that is unsuitable for use as a synthetic resin skin material on the surface of a molded body to be heat-molded.

[0103] (2. Production of Molded Body) The synthetic resin skin material obtained in the Examples, Comparative Examples, and Reference Examples was placed in a mold, and the resin for the molding substrate (acrylonitrile-butadiene-styrene copolymer (ABS)) was heated and melted at a temperature of 200 to 300°C, fed into the mold, and injection molded to obtain a molded article in which the synthetic resin skin material was placed on the surface of the molding substrate. Note that the above temperature condition is the melting temperature of the resin before injection.

[0104] (3. Evaluation of Molded Product) The obtained molded articles were evaluated according to the following criteria, and the evaluation results are shown in Table 1 below. Regarding the evaluation results other than the retention of the uneven pattern, those that showed no change or deterioration in appearance when visually observed were given an "A", and those that showed change or deterioration in appearance were given a "B". Also, "-" indicates that the evaluation was not performed.

[0105] 3-1. Retention of textured patterns The surface roughness of the surfaces of the molded articles obtained using the skin materials of the Examples, Comparative Examples, and Reference Examples was measured using a surface roughness meter (Surfcom 130A, manufactured by Tokyo Seimitsu Co., Ltd.). The results were compared with the surface roughness of the synthetic resin skin material before molding, and the recess depth retention rate was calculated. Furthermore, if the synthetic resin skin material on the surface of the molded body after the molded body has been heated and molded has a recess depth retention rate of 50% or more, it is considered to be at a level that does not pose a practical problem even when used to form a molded body that requires heating, and if it is less than 50%, it is considered to be at a level that poses a practical problem.

[0106] 3-2. Solvent resistance (gasoline, kerosene) The molded articles obtained using the skin materials of the Examples, Comparative Examples and Reference Examples were immersed in gasoline and kerosene (light oil) as solvents for 30 minutes, respectively, and then removed and left to stand for one week. After standing, the appearance of the molded articles immersed in gasoline and kerosene was evaluated visually according to the following criteria. In the following criteria, a rating of A is judged to be a level that poses no practical problems, and a rating of B is judged to be a level that poses practical problems. A: Visual observation revealed no deterioration of the molded body due to the solvent. B: Visual observation revealed deterioration in appearance due to deterioration of the molded body by the solvent.

[0107] 3-3. Chemical resistance (sulfuric acid, sodium hydroxide solution) The molded articles obtained using the skin materials of the Examples, Comparative Examples, and Reference Examples were immersed in chemicals such as sulfuric acid and a 0.4% by mass aqueous solution of sodium hydroxide for 30 minutes, and then the molded articles were removed and left to stand for one week. After standing, the molded articles immersed in sulfuric acid and the aqueous sodium hydroxide solution were visually evaluated for appearance. The evaluation was based on the following criteria. In the following criteria, a rating of A is judged to be a level that poses no practical problems, and a rating of B is judged to be a level that poses practical problems. A: Visual inspection revealed no chemical deterioration of the molded body. B: Visual observation revealed deterioration in appearance due to chemical degradation of the molded body.

[0108] 3-4.Moldability The appearance of the molded articles obtained using the skin materials of the Examples, Comparative Examples, and Reference Examples was evaluated visually according to the following criteria. A: Visual inspection revealed no wrinkles, resin leakage, gate damage, or whitening on the surface of the molded product. B: Visual inspection confirmed one or more of wrinkles, resin leakage, gate damage, and whitening on the surface of the molded product, and deterioration that is problematic for practical use was confirmed. In the following criteria, a rating of A is judged to be a level that poses no practical problems, and a rating of B is judged to be a level that poses practical problems.

[0109] In Table 1 below, "PP" represents polypropylene resin, "ABS" represents acrylonitrile-butadiene-styrene copolymer, "PVC" represents polyvinyl chloride resin, "PC" represents polycarbonate resin, and PMMA represents polymethyl methacrylate resin. "-" indicates that the skin material does not have the corresponding layer.

[0110] [Table 1]

[0111] The results in Table 1 show that the synthetic resin skin materials of the Examples are excellent in retaining the textured (grained) pattern on the surface even under heated conditions, and the molded articles obtained using them have good moldability and excellent durability in terms of solvent resistance, chemical resistance, etc. Even after heat molding, the textured (grained) pattern formed on the surface of the synthetic resin skin material is excellently retained, and the solvent resistance and chemical resistance are at acceptable levels, demonstrating excellent performance equivalent to that of the Reference Example skin material, which has a skin layer containing a more expensive fluororesin.

[0112] On the other hand, the synthetic resin skin material of Comparative Example 1, which used PMMA for the skin layer, had an extremely low retention rate of recess depth, and when the molded product was obtained after heat molding, the uneven pattern had almost completely disappeared, making it impossible to evaluate. Furthermore, the skin material of Comparative Example 2, which has a skin layer containing a fluororesin similar to that of the Reference Example but contains an ABS resin intermediate layer, is found to be at a level that is problematic for use in the Examples, both in terms of the retention rate of the recess depth as a skin material and in terms of the retention of the uneven pattern of the molded article obtained using the synthetic resin skin material. This shows that the skin materials of the examples, having a skin layer containing PP resin, are excellent in selectivity for the thermoplastic resin in the intermediate layer, and offer greater freedom in selecting the thermoplastic resin to be used in the intermediate layer than skin materials using a skin layer containing fluororesin. The skin material of Comparative Example 3, which contains a PP resin in the skin layer but does not have a base layer, retains the uneven pattern to a level acceptable for use in the examples, but is poor in heat moldability and is not practical for use in forming molded articles.

[0113] In the skin materials of Examples 1 to 6, the content of fluorine atoms was below the detection limit in the following evaluation, which shows that they have performance equal to or better than that of conventional technologies, even without containing expensive fluororesin. (Evaluation method) The fluorine content was analyzed by X-ray fluorescence analysis (XRF) in accordance with JIS K 0119 (2008). The analysis conditions were energy dispersive, room temperature and pressure measurement, and a spot size of 100 μm. [Explanation of symbols]

[0114] 10, 20 Synthetic resin skin material 12 Base material layer 14 Middle Class 16 Skin layer containing polypropylene resin (specific skin layer) 18 Design Layer

Claims

1. a base layer containing a thermoplastic resin; an intermediate layer provided on one surface of the base layer and containing a thermoplastic resin including at least one selected from the group consisting of an acrylonitrile-butadiene-styrene copolymer and a vinyl chloride resin; a skin layer provided on the opposite side of the intermediate layer from the base layer, the skin layer having an uneven pattern on the surface opposite to the intermediate layer side, and containing a polypropylene resin; Equipped with The thickness of the intermediate layer is 50 μm to 200 μm. Synthetic resin skin material.

2. 2. The synthetic resin skin material according to claim 1, wherein the substrate layer comprises at least one resin selected from the group consisting of an acrylonitrile-butadiene-styrene copolymer, a polycarbonate resin, and a vinyl chloride resin.

3. 3. The synthetic resin skin material according to claim 1, further comprising a design layer between the intermediate layer and the skin layer.

4. The synthetic resin skin material according to claim 3, wherein the design layer is a printing ink layer containing at least one resin selected from the group consisting of acrylic resin, urethane resin, polyolefin resin, polyamide resin, and vinyl chloride-vinyl acetate copolymer.

5. 5. The synthetic resin skin material according to claim 1, further comprising a surface treatment layer on the surface of the skin layer on the side having the textured pattern.

6. The surface treatment layer is at least one selected from the group consisting of acrylic resin, urethane resin, polyolefin resin, polyamide resin, silicone resin, and vinyl chloride-vinyl acetate copolymer.

6. The synthetic resin skin material according to claim 5, comprising at least one kind of synthetic resin.

7. The synthetic resin skin material according to any one of claims 1 to 6, which is a skin material for a hot-molded product.

8. providing a skin layer comprising a polypropylene resin; forming an intermediate layer having a thickness of 50 μm to 200 μm using a resin composition containing a thermoplastic resin including at least one selected from the group consisting of an acrylonitrile-butadiene-styrene copolymer and a vinyl chloride resin; forming a substrate layer using a thermoplastic resin composition containing a thermoplastic resin; a step of laminating the surface layer, the intermediate layer, and the base layer in this order to obtain a laminate; and A method for producing a synthetic resin skin material, comprising a step of laminating and embossing the skin layer side of the obtained laminate using a squeeze roll to form a textured pattern on the surface of the skin layer opposite to the intermediate layer side.

9. The method for producing a synthetic resin skin material according to claim 8, further comprising the step of forming a design layer between the skin layer and the intermediate layer.

10. 10. The method for producing a synthetic resin skin material according to claim 8, further comprising the step of forming a surface treatment layer on the surface of the skin layer on the side having the textured pattern.

11. A molded article comprising a molding substrate and the synthetic resin skin material according to any one of claims 1 to 7 disposed on the surface of the molding substrate.

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